FY 77-78
Research Report
The Impacts Of Ultra
Violet B Radiation On
Biological Systems:
A Study Related To
Stratospheric Ozone
Depletion
Submitted To:
The Stratospheric Impact Research
and Assessment Program (SIRA)
*ป
Tile f.S, Environmental Protection Agency
Washington. D.C. 2O6O4
Volume II
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DISCLAIMER
THIS REPORT HAS NOT BEEN REVIEWED FOR APPROVAL BY THE
AGENCY AND HENCE ITS CONTENTS DO NOT REPRESENT THE VIEWS AND
POLICIES OF THE U.S. ENVIRONMENTAL PROTECTION AGENCY, NOR DOES
MENTION OF TRADE NAMES OR COMMERCIAL PRODUCTS CONSTITUTE ENDORSEMENT
OR RECOMMENDATION FOR USE.
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CONTENTS
SIRA FILE //
VOLUME I
1.
Study Of Increase In Skin Cancer As A Function
Of Time And Age And Changing Stratospheric Ozone:
Need For Careful Measure Of The Ultraviolet Dose
t 132.11
The Influence Of Age, Year Of Birth, And Date On
Mortality From Malignant Melanoma In The Populations
Of England & Wales, Canada And The White Population
Of The United States
3.
Non Melanoma Skin Cancer Surveys In The United States
- An Environmental Epidemiologic Project
* 132.31
9 142.11
5. Biological Effects Of Ultraviolet Radiation On Plant
Growth And Function
6. Effects Of UV-B Radiation On Selected Leaf Pathogenic
Fungi And On Disease Severity
7. The Effect Of Ultraviolet (UV-B) Radiation On Englemann
Spruce And "Lodgepole Pine Seedlings
VOLUME II
8. UV-B Biological And Climate Effects Research
9. Ultraviolet Effects Of Physiological Activities Of
Blud-Green Algage
10. Impact Of Solar UV-B Radiation On Crops And Crop
Canopies ................... . ............... .
11. High Altitude Studies Of Natural, Supplemental
And Deletion Of UV-B On Vegetables And Wheat
VOLUME III
12. UV-B Radiation Effects On Photosynthesis And
Plant Growth
* 142.21
* 142.21g
9 142.22
# 142.23
9 142.24
9 142.25
9 142.26
13. Influence Of Broad Band UV-B On Physiology And
Behavior Of Beneficial And Harmful Insects
142.27
142.28
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: SIRA FILE #
14. A Study Of The Effects Of Increased UV-B
Irradiation On Environmental Dissipation Of
Agricultural Chemicals ............................. ... ..... . # 142.29
*V" "'- * - . '
15'. Biological Effects Of Ultraviolet Radiation
On Plant Growth And Development In Florist And
Nursery Crops ............................................... $ 142 . 210
16. Biological Effects Of Ultraviolet Radiation On Cattle:
Bovine Ocular Squamous Cell Carcinoma ...... ................. tf 142 . 211
. 17. Radiation Sources And Related Environmental Control
:' For Biological And Climatic Effects UV Research (BACER) ..... # 142.212
18. Instrumentation For Measuring Irradiance In The
UV-B Region ....... ......^.|./. ซ .XA...^.....^ .i%i^A.|.->^.-. ............. # 142.213
19. Annual Report To EPA, Bacer Program For I
Fiscal Year 1978 .................................. . ......... # 142.34
20. Penetration Of UV-B Into Natural Waters .... ............. .... # 142.36
21. Higher Plant Responses To Elevated Ultraviolet
Irradiance ... ............................................... 9 142.41
22. Assessment ~Qf The Impact Of Increased Solar
: Ultraviolet Radiation Upon Marine Ecosystems ........ ....... . # 142.42
23. UV-B Instrumentation Development ......... ......... ..... ..... #142.51
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iM BIOLOGICAL AND CLIil^E EFFECTS RESEARCH
TERRESTRIAL FY 77
IrPfiCT OF SOLAR UV-B N/^IATION ON CR3P PRODUCTIVITY
FEBRUARY 23, 1978 FINAL REPORT
BY
R,H, BIGGS, FRI^IPAL IWESTIGATOR ArlD
S,V, KOSSITH, PROJECT DIRECTOR
PREPARED FUR
UNITED SWES BEPT, AGRICULTURE/EiWIRO^ErilML ProTEHTIOr! AGBO
VIASHIf-IGTOf-l D,C, 2CKIGO
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bV-B BIOLOGICAL AND CLIFWE EFFECTS RESEARCH
TERRESTRIAL FY 77
IIWT OF SOLAR UY-B RADIATION ON CROP PRODUCTIVITY
FEBRUARY 28, 1978 FINAL REPORT
BY
R,H, BIGGS, PRINCIPAL INVESTIGATOR AND
S,V, KOSSUI}i, PROJECT DIRECTOR
R)R
UNITED STATES DEPT, AGRICUlJURE/ENVIROfteiT/L PROTECTION AGENCY
WASHINGTON D.C. 20/160
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Acknowledgements
Many hands, hearts and a lot of hard work were contributed by the follow-
ing researchers in Florida: Lawrence Halsey, Gene Albrigo, Chet Hall, Steve
Kostewicz, Bob Sutherland, Jon Bartholic, Barbara Cosper, Richard Bennett,
Beverly Banks, Dixie Biggs, Brian Milum, Jeff Yagoda, John Taylor, Bob Cook,
Paul Miller, Gene Hannah, David Gancarz, Mick Frank, Yvonne McCormick, Barbara
Hanson, Ferris Johnson, Dian Stamper, John Knettle, Kevin Milum, Esau Durant,
Bruce Mclntyre, Scott Privett, Malcolm Manners, Augie Cassiato, Cindy Beaston,
and Frank Narki.
The same dedicated effort was headed up by Alan Teramura at the Duke
University Phytotron who had conscientious help from Eric Bronner, Catherine
Johnson, Jonathan Weiner, Carol Hellmers, Eric Knoerr, Elizabeth Flint, Robert
Strain, Teresa Mills, Donna M. Dodson, Brett Clark, Mary Fluke, Elizabeth Grey,
Frederick Huber, Kathryn Jones, Pope Langstaff, Jeffrey Cooper-Smith, and Tim
Walker.
We especially acknowledge the collaborative efforts between our group and
that of Drs. H. Allen and Cu VanVu of the USDA/ARS, the group at Beltsville,
MD under the direction of Dr. Harry Carns and Drs. A. Forziati and Ed DeFabo
of the EPA. A special thanks to Dr. F.G, Martin for statistical analyses.
Appreciation is extended to Dr. Henry Hellmers, Director of the Duke
Phytotron for his cooperation and assistance in the experiments and to the
talented efforts of his staff headed by Newton McQuay with help from Jason
Yeager, Larry Giles, Jerome Smith, Karl Buckner, and others. Thanks also to
Phyllis Mills for handling secretarial and monetarial affairs. Work at the
Duke Phytotron was supported by National Science Foundation Grant #DEB76-041$0
to Dr. Hallmers.
Appreciation is also extended to Ginny Hardin and Elaine Summers for han-
dling internal affairs within the Fruit Crops Department.
Appreciation is also extended to the other professional staff at the
University of Florida who have been supportive of this research effort.
ii
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CONTENTS
I. UV-B Radiation Measurements, Instrumentation and Methodology.
II. Effects of Ultraviolet-B Radiation Enhancements on Eighty-two
Different Agricultural Species.
III. Effects of Ultraviolet-B Radiation Enhancements on Soybean
and Watermelon Varieties.
IV. Effects of Ultraviolet-B Radiation Enhancements Under Field
Conditions on Potatoes, Tomatoes, Corn, Rice, Southern Peas,
Peanuts, Squash, Mustard and Radish.
V. Effects of Ultraviolet-B Radiation Enhancements and PAR Flux
Densities on Several Growth Parameters as Related to NCE, Dark
Respiration, and Transpiration of Soybean and Several Growth
Parameters of Wheat.
VI. Effects of Ultraviolet-B Radiation Enhancements on Cuticle and
Epidermal Cell Development.
VII. Effects of Ultraviolet-B Radiation Enhancement on Inudction of
Phenylalanine Ammonia Lyase and Ethylene Production.
VIII. Effects of Ultraviolet-B Radiation Enhancement on Chlorophyll
a, b and Total of Avocado Leaves.
IX. Effect of Ultraviolet-B Radiation Enhancement on Abscission,
Ethylene Production, Abscisic Acid and Several Enzymes of Legumes.
iii
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UV-B RADIATION MEASUREMENTS, INSTRUMENTATION AND METHODOLOGY
Solar UV-B Irradiance
Detailed spectral analyses of the UV radiation reaching the ground are
of utmost importance to studies of the type covered by this report because
of the pronounced wavelength dependence of most biological and natural
photochemical reactions. Ultraviolet radiation shorter than 320nm to natural
cut-off levels was the area of experimentation under consideration. Changes
in spectral irradiance for this portion of the spectrum (280-320nm, comonly
denoted as UV-V*) are analytically expressed as a function of solar angle
and various atmospheric parameters, including atmospheric ozone concentration.
.Thus, analytical analyses of the factors contributing to variations in
spectral irradiance in this region accomodate solar angle, ozone layer thick-
ness, aerosol density, ground albedo, elevation above sea level and cloudi-
ness. Germane to this study is the ultraviolet radiation increases that
would accompany a change in the ozone layer thickness as it would influence
*Classically (Coblentz-Stair, cited in Meyer and Seitz, 1942), the UV-B
consisted of range of wavelengths, 280-315nm. By common usage, the UV-B
now ranges up to 320nm.
1-1
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crop productivity. Critical to the experimentation on the effects of UV-B
radiation on plants is a knowledge of the dose applied and the manner in
which it is applied as related to the stage of growth and development of the
organism. This section will deal x?ith measurements of irradiance and
methodology of exposing plants to UV-B radiation enhancement levels used in
this study.
Dosimetry and Units of Measurements
For this report on the biological effects of the solar UV-radiation on
plants, we have used International Standard (SI) radiometric units, and in those
areas not well delineated, we have used the suggestions of Rupert (197A that
have been adopted for use by the Society of Photochemistry and Photobiology.
A brief description of some aspects of terminology and dosimetry germane
to this report follows:
Terminology of Radiometry and Dosimetry
Force is the product of mass times acceleration (Newton's Second Law)
if mass is constant. The unit of force is the Newton (MKS units = kg ' m " s ).
Energy (kinetic) is the space integral of force, or commonly, the product of
force x distance. The unit of energy is the joule (MKS units = N m). Power is
the rate at x^hich energy is expended. The unit of power is the watt (1 watt =
1 joule s ). '.';
/
The terminology of radiometry applies to all electromagnetic radiation.
Terms relating to a beam of radiation passing through space (without regards to
origin or destination) are radiant energy and is the total amount of energy in
the beam (for as long as it persists); radiant energy flux, the power of the
beam, or the rate of flow of energy; and radiant energy flux density, the power
crossing a unit area normal to the beam. Terms relating to a source of radiation
1-2
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are radiant intensity, the power emitted per steradian into space by the en-
tire source; and radiance, the power emitted per steradian into space by a
unit projected area of the source surface. A term relating to the object
intercepting the radiation is the irradiance, the power striking the object
per unit of the object, or the energy per unit area per unit time. In biolog-
-2 -1 -2
ical applications, irradiance is expressed in J m s or W m (See Table 1).
The terminology of dosimetry as applied to biology is related to the
organism irradiated. The integral dose is the total radiant energy incident on
the object (e.g., ergs per bacterium). The dose is the amount of energy incident
2
on a unit area of the object (e.g., ergs per mm ). The dose rate (analogous to
irradiance) is the power incident on the object per unit area, or the energy per
2 1
unit area per unit time (e.g., erg mm sec ). Energy "incident upon" an object,
does not imply that the energy is "absorbed by. the object. Dosimetry quantities
related to that actually absorbed are energy x mass in physical dimensions
(see Table 2).
Instrumentation
Gamma Scientific Spectroradibmeter
A model 2900 spectroradiometer was purchased from Gamma Scientific,.Inc.,
3777 Ruffin Road, San Diego, CA 92123, in 1973 for use in Climatic Impact As-
sessment Program. The characteristic of the instrument has been described by
Green jilt auL. (1975). The only modification in the basic instrument has been
the installation of a solar-blind filter between the monochromator and phototube
and a helipot in the preamp circuit of the phototube to increase sensitivity.
Both of these changes were under the direction of Mr. Karl H. Norris, Instru-
mentation Res. Laboratory AMRI, ARS, USDA, Beltsville, Maryland. The instru-
ment was interfaced to a Hewlett-Packard model 2100 computer for monitoring solar
UV-B radiation, calibrating other instruments and establishing conditions for
1-3
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Table 1. Power and energy conversion factors.
Power
(irradiance, energy fluence rate,
dose rate)
Ergls"1.!"2 = 10"1 W.m"2'
-1 -2 -3 -2
Erg.s .cm =10 W.ra
Erg.s .m = 10 W.m
Energy (1 Joule = 1 watt-second)
(density of incident energy, energy
fluence, dose)
Erg.mm
J.m
~2
-2 -3 -2
Erg.cm = 10 J.m
-2 -7 -2
Erg.m = 10 J.m
7 f\ 9
W.mm = 10 W.m
-2 4 -2
W.cm = 10 W.m
W.m
1 W.m
-2
T< -2
J.mm . =
J.cm =
J.m =
106 J.m"2
J.m
1 J.m
-2
-2 3 -2
mW.mm = 10 W.m
O O
mW.cm = 10^ W.m
-2 -3 -2
mW.m = 10 W.m
-2 3 -2
mJ.mm = 10 J.m
-2
mJ.m = 10
mJ.cm
-2
1C-1 J.m"2
J.m
-2 -2
yW.mm = 1 W.m
2 2 2
yW.cm = 10 W.m
yW-m = 10 W.m
9
yJ.mm
-2
1 J .m
-2
_2 _2 _2
yj.cm = 10 J.m
T -2 in-6 _ -2
yJ.m = 10 J.m
Equivalent Power .Terms
on a X basis per nanometer
3 1 3
mW.m .nm x 10
IT
W.m
.nm
-2 -1 -3 -2 -1
W.m .um x 10 = W.m .nm
2 1 3 2 1
mW.m .nm x 10 = W.m .nm
2 -1 -3 -2 -1
yW.cm .(lOnm) x 10 = W.m .nm
1 2 1 3 2 " 1
Erg.sec .cm .nm x 10 = W.m .nm
-2 9 -2
W.h.mm = 3.6 x 10 J.m
W.h.cm"2 = 3.6 x 107 J.m"2
W.h.m"2 = 3.6 x 103 J.m"2
2 6 2
mW.h..mm = 3.6 x 10 J.m
-2 4 ' -2
mW.h.cm = 3.6 x 10 J.m
-2 -2
mW.h.m = 3.6 J.m
-2 3 -2
yW.h.mm = 3.6 x 10 J.ra
-2 1 -2
yW.h.cm = 3.6 x 10 J.m
-2 -3 -2
yW.h.m = 3.6 x 10 J.m
1-4
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Table 2. Summary of Dosimetric Quantities
Source: Adapted from Rupert, 1974
Physical
dimensions
energy x area
area
-1 .. . -1
energy x area x time
area x time
Units
_2
joule per square meter (J m )
-2
per square meter (m )
joule per square meter and
second (J m~2 s~^-~)
per square meter and second
Suggested
name
energy fluence -
photon fluence
energy fluence rate
photon fluence rate
Suggested
symbol
F ;
P .
dF/dt or F
dP/dt or P
-1
energy x mass
1 1
energy x mass x time
joule per kilogram (J kg )
joule per kilogram and second
(J kg'1 s-1)
absorbed dose
absorbed dose rate
D
dD /dt or D
a a
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the field irradiator. For use in environmental control chambers and the
greenhouse, the protocol outlined in Table 3 and 4 were used.
When the Gamma Scientific Spectroradiometer was interfaced to the com-
puter, the "UV" set of programs were designed to control the Gama Scientific
Spectroradiometer and to collect, convert and analyze the ultraviolet global
spectrum from 280 to 340 namometers. Options were available to record the
original data on paper tape for later analysis. Program UVRD was designed
for this later analysis. A real time analysis option (Program UVBT) was also
available to convert to milliwatts per square meter per nanometer through con-
version values (R values) stored on disc files. An update on the calibration
was obtained through Program CALIB which was used in conjunction with the
Spectroradiometer and the tungsten-halogen standard radiance source (See Cal-
ibration Standards p.7).
The measured data was quadratically interpolated to even wavelengths with
Hewlett-Packard software. The source signal was then converted to flux units
and an integration was performed from 295 nm to 340 nm using the Simpson Method
2
to give the total UV flux in W/m . The converted signal was then modified by
a weighting function (see Table 10):
DNA = exp - {tt.-265)/2l]2
and another integration was performed from 295-340nm.
Provide the instrument was turned on and set up properly as outlined
below, the programs could be activated from and the date returned to, any re-
mote terminal via a telephone.
The raw data (wavelength transducer and photomultiplier output) were
sampled by an H.P. Digital Voltmeter. An initial wavelength search was made
by triggering the monochrometer grating motor through the relay board until
the initial starting wavelength (289nm) is located. The scan was then initiated
and controlled through the relay board to step approximately 1 nanometer at a
time. A 500 millisecond delay was required before reading each signal to allow
1-6
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Table 3. Protocol for use of the Gamma Scientific Spectroradiometer at
locations other than in the solar scanning tower automated with
the Hewlett-Packard computer. .
The following procedure and attached data taking form (Table 4) should
aid in making the UV light measurements in the greenhouses and growth . '
chambers. Anyone using the instruments for the first time should be
instructed on proper use.
1) Do not turn unit on yet.
2) Set range switch to "auto".
3) Turn HV "course" extreme counterclockwise.
4) Close slits.
5) Set response to S(slow) M(medium) or F(fast).
6) Turn unit on.
7) With function switch on "HV" adjust for 350 volts with course and fine.
8) With function switch on "operate" depress zero button and adjust zero.
9) Turn function switch back to "HV" and maintain 350 throughout.
10) Set range switch to "-1" (Mixie bulb is out, count 2 turns counterclockwise),
11) Attach fluke meter and switch box to monochromator. Put fluke on
2 volt range.
12) Turn wavelength to 200nm, open slits and readjust zero knob until
fluke meter is zeroed.
13) Close slits and take another reading, (repeat steps 12 and 13
periodically).
14) Open slits and take data as required on attached forms.
15) Calculate DNA weighted flux from the following equation:
9
DNA = ฃ Cal( Xi)* SigCXi)
e=l
16) Calculate UV-B
, -,( m , , seu ,.
17) Take a sun burn meter reading
18) Repeat data taking for 5, 10, 20, 30, 40, 50 a.nd lOO.cm, also do one with.
light out. For 30cm distance take data every nanometer from 290-340nm.
19) Construct a graph of UV-B vs distance and extrapolate for deduction of
intermediate distances.
20) Return equipment to the horticultural unit solar scanning tower by 7:30AM.
1-7
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Table 4. Sample of the data recording -sheet to be used with the Gamma Scientific
Spectrora.diometer for determining UV-BS in greenhouses &growth chambers
ROBERTSON METER=
DISTANCE=
ROBERTSON METER=_
DISTANCE=
NM
290
295
300
305
310
315
320
325
330
200
SIG
CAL
3.000
1.545
0.751
0.302
0.114
0.038
0.012
0.004
0.001
SUM '
CALxSIG
NM
290
295
300
305
310
315
320
325
330
200
SIG
CAL
3.000
1.545 .
0.751
0.302
0.114
0.038
0.012
0.004
0.001
SUM
CALxSIG
ROBERTSON METER?
DISTANCE=
ROBERTSON METER-
DISTANCE=
NM
290
295
300
305
310
315
320
325
330
200
SIG
CAL
3.000
1.545
0.751
0.302
0.114
0.038
0.012
0.004
0.001
SUM
SIGxCAL
NM
290
295
300
305
310
315
320
325
330
200
SIG
CAL
3.000
1.545
0.751
0.302
0.114
0.038
0.012
0.004
0.001
SUM
CALxSIG
1-8
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for stablization of the electronics and to allow for "scan motor flyby."
This essentially limited the speed of the scan to approximately 2 nm/sec. Data
from 280nm to 285nm was assumed to be dark current and scattered light gener-
ated signals and was used for correction by subtration from the entire spectrum.
The sun-burn UV radiometer output was sampled immediately before and after each
scan. Also, it was sampled separately every 5 minutes and recorded by a potent-
iometric strip chart recorder. (This portion of the grant was under the direc-
tion of Dr. Jon Bartholic).
Every half hour from 9 am to 4 pm a scan was made of the natural solar
UV-B influx and a mean UV-B flux for the day computed. The mean natural UV-B
flux for each crop was arrived at by averaging the daily fluxes while the crop
was growing.
Optronics Model 741 Spectrorad-iometer
A model 741 of the specifications- outlined in Table 5 was purchased
from Optronics Laboratories, Inc., 7676 Fenton Street, Silver Springs, MD
20910. It was equipped with a Hewlett-Packard 9815A calculator. The inst-
rument was.originally calibrated against the secondary standard owned by Op-
tronics Laboratories, Inc. A comparison of this secondary source with the
secondary standard lamp we have used for calibration agreed within - 2%. An
inter-comparison between measurements made with the Optronics Model 741 spec-
troradiometer, the Gamma .Scientific spectroradiometer and a spectroradiometer
in Mr.'Karl Norris' laboratory, AMRI, ARS, USDA, Beltsville, MD all agreed with-
in - 4%.
Optronics Model 725 Radiometer
A model 725 radiometer of the specifications outlined in Table 6 was
supplied by Optronics Laboratories Incorporated. It was calibrated by Mr.
2
Karl Norris for a UV-B irradiance of 2.6 W/m to give a full scale deflection
using 5 mil Cellulose Acetate filtered UV-B irradiance from an FS-40 lamp
1-9 -
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Table 5. Specifications for Optronics Laboratories, Inc. Model 741
UV-B Spectroradiometer.
MODEL 741 UV-B SPECTRORADIOMETER
Preliminary Specifications
Wavelength Range .250 to 400 nm with option to extend
to 800 nm
Bandpass 2 nm i 0. 5 nm
Scanning Time 1 and 5nm/sec
Response Time 1 and 10 sec (0 to 99%)
Wavelength Accuracy (dial reading). t 0- 5nm
Wavelength Precision (cam pulse) . . _ O.Znm
Spectroradiometric Accuracy j" 3%
Repeatability t 1%
Stray Light lO"4 at 285 nm*
HV Power Regulation 0,1%
Angular Response Input optics with cosine response to
within + 5% at 45ฐ
Dynamic Range 10'
Irradiance Range 10-10 to 10"^ W/cm^nm
Noise Equivalent Irradiance 10-10 W/cm^nm at 280 nm
Readout 4 digit display of log amperes
Recorder Output 0 to 7 V with 1 volt per decade
Data Acquisition Interval 1 nm interval sync pulse
Digital Output 4 digit BCD, Hold and control signals
Size: Optics 4x7x8 inch
Electronics 4-1/2 x 8 x 11 inch
Weight: Optics Less than 10 Ibs.
Electronics Less than 10 Ibs.
Operating Environment:
Temperature 10 --37ฐ C
Humidity to 80%
Electrical Requirements 105 to 125V, 60 Hz
* measured with a xenon source and a 0. 5 mm cellulose acetate filter
1-10
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Emphasizing Precision and Accuracy
Preliminary Bulletin 51
MODEL 725 UV-B RADIOMETER
The Model 725 is a portable, battery operated radiometer specifically
designed for measuring the ultraviolet irradiance of artifical sunlight which
is used in many growth chambers, greenhouses, field plots, etc.
The design and selection of components are optimized for the UV-B spectral
region. A peak response at 300 nm is obtained using a filtered, solar-blind
diode. A dome-shaped teflon diffuser serves as an unusally effecient uv
cosine receptor. The electronics and the removeable optical sensor is housed
in an attractive wooden box suitable for laboratory or field use. The optical
sensor is small and light weight allowing placement of the sensor into growth
chambers with a minimum of disturbance to growing plants.
The electronics consists of a single-stage operational amplifier, a calibration
trim-pot, and a battery test pushbutton switch. The readout consists of a
single range analog display and a BNC recorder output which provides an
analog signal equivalent to the voltage displayed on the panel meter. The unit
is calibrated to read "UV-B" watt/cm^ using the BZ type lamp standard.
SPECIFICATIONS
Peak Wavelength Response . .' 300t5nm
Response at 280 and 320 nm Down less than 70%
Response at 500 nm . . Less than .01% of peak
Stability +3%/6 months
Accuracy ฑ2%
Readout. 0-1 Volt analog panel meter
external recorder output
Response Time. 1 sec.
Power Requirement ' Internal battery pack or 105-125 VAC
Continous Battery Operation. 200 hours
Recharge Time 14-16 hours
Size 9x3x4
Price $350.00
1-11
7676 FENTOIM ST. o SILVER SPRING. MD. 2O91O (3O1) 587-2255
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that would be equivalent to 5 UVBSE when "weighted" by A.Z 9 as described by
the equation of Cams et al. (1977) . Figure 1 demonstrates an intercompar-
ison between measurements using the model 725 radiometer meter/reading and
the Gamma Scientific spectroradiometer with FS-40 Westinghouse "sun lamps" and
2
a 5 mil Cellulose Acetate filter. The read-out on the latter is both W/m
_2
and "weighted"mW/m (see page 9 for description of latter). It should be
noted that the radiometer cannot be used to adequately describe a "weighted"
or total irradiance. Radiometers are very useful as monitoring devices once
calibrated conditions have been established but should not be used for char-
acterizing UV-B irradiance conditions.
Sun-Burn UV Meter . .
A sun-burn, UV radiometer supplied to investigators associated with the
Climatic Impact Assessment Program was available for monitoring solar radiat-
ion and experimental test systems. The instrument has been well described in
the CIAP monograph 5, Chapter 2. However, because of its built-in weighting
function, it was only used as a monitoring radiometer.
2145 Type RV meter
A small hand-held 2145 UV meter modified by installing a filter over
the radiation detector of a General Electric type 214 illumination meter, was
used to monitor the FS-40 Westinghouse "sun lamps." It was supplied by Drs.
Lowel E. Campbell and Richard W. Thimijan, Agricultural Equipment Laboratory,
PPHI, ARS, USDA as part of the overall program.
Calibration Standards
A standard lamp was purchased from Gamma Scientific, Inc. april '11, 1973.
It was rechecked for spectral irradiance by Optronic Laboratories in July 1977
1-12
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Figure 1
2.7
2.S
2.5
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
O.I
0
/
_ &-3I.3
;' '^
- /
/
/
/
ฉซ-2 UV-BsT
ฉ -
/
- ฉ _
/
ฉ
_ /
^ *-l UV-8seu ' -
/_
-
"/
22.7
21.6
17.9
14.5
1 .1
10.7
7.1
WEIGHTED
-m W-M2
- /
-1 METER READINGS
/ 1 .. 1 1 1 1 ! 1 | 1 1
12345 6 78 9 10
Fig. 1. Calibration of the Optronic 725 radiometer with the Gamma Scientific
spectroradiometer showing the relationship between Optronic 725 meter
readings and the total W/m2 and weighted mW/m2 as determined with the
spectroradiometer and computer. The source of irradiance was an FS-
40 lamp filtered with 5 mil C.A.
1-13
-------
and found to vary by less than 2% from the initial calibration report. The
standard vras a 1000-watt quartz-halogen, tungsten coiled-coil filament lamp,
designated by model 230, type SN-99. When operated at 8.3 amperes at a distance
of 50 cm, the irradiance per 5nm of wavelength was rated in calibration as
shown in Figure 2.
In reality, the calibration values traceable to the National Bureau of
Standards, were given only at 280, 290, 300, 320 and 350 nanometers.. For
other wavelengths, the calibration values were interpolated through an ap-
proximation to the Blackbody Function, i.e.,
c
I /i
Vj- ,
I =
c
X where 1=
I
o
X5
1
X
JC
(e*- 1)
A second standard was purchased from the National Bureau of Standards
for use in the 280-230 nm range. This was a 20-watt fluorescent lamp. The
operating condition and output are shown in Table 7.
A Solar Reference Day
On April 28, 1977 a number of measurements were made every 30 minutes
during the day with a Gamma Scientific Spectroradiometer. The day was chosen
because it was a clear one during approximately the mid-point of the spring
vegetable growing season. Data of Figure 3 demonstrates the irradiance per.
nanometer of wavelength from 290-340nm." Total irradiant flux for a 295 to
340 nm band width for 15 measured and 6 interpolated values are shown in Table
2
8. Total flux was calculated to be 126.557 W/m of total irradiance. This
was taken to be the solar reference day and is the solid line plotted on Figure
3 which is labelled "calculated value." A check for the calculated curve was
an actual measured solar spectrum out of the several that had a total irradiance
1-14
-------
Figure 2
'|,62
CM
Ul
o
z
Q
<
o:
i63=!
280 300 320 340 360
WAVELENGTH (nm)
380
400
Fig. 2. Calibration curve for the SN-99 1000 x^att quartz-halogen,
tungsten coiled-coil filament standard lamp.
1-15
-------
Figure 3
EX IO'4
CALCULATED VALUE
MEASURED AT
1236 hrs.
^2_MEASUREO AT
1432 hrป.
290
300
310
320
330
340 350
Fig. 3. Two measured solar UV-B irra.diance spectra and a calculated
reference solar spectrum (see text for method of calculation
of reference spectrum).
1-16
-------
Table 7. Spectral irradiance of Lamp No. BZ 11 when operated
at a voltage of 0.250 RMS.
Wavelength (nm) Spectral Irradiance (W/cm )
280 0.00508
282 0.01420
284 0.03490
286 0.08170
288 0.17400
290 0.333
292 0.591
294 0.974
300 2.930
304 4.520
306 5.190
308 5.660
318 5.170
320 4.700
322 4.210
324 3.740
326 3.290
328 2.890
330 2.530
338 1.500
340 1.320
342 1.160
344 1.010
346 0.891
348 0.778
350 0.684
1-17
-------
Table 8. Total irradiance and weighted irradiance
for April 28,; 1977 which was a clear day
at Gainesville, Florida.
Total Irradiance Weighted Irradiance
Time (EST) 295-340nm(W/m2) .295-340nm (mW/m2)
0705 0.8001 0.4001
0735 1.726 1.336
0805 2.565 2.288
0835 3.652 3.663
0905 4.808 5.618
0935 5.9001 7.8501
1005 7.003 10.070
1035 7.767 12.261
1105 8.560 14.070
1135 9.308 16.366
1205 9.665 17.212
1235 9.796 17.478
1305 9.658 17.044
1335 8.922 15.390
1405 8.500 13.450
1435 7.667 11.226
1505 6.660 9.288
1535 5.3301 .7.1201
1605 4.0001 5.1501
1635 2.8001 3.2501
1705 1.4701 1.20Q1
126.5572 191.7303
Interpolated values.
Equals 227,803 W-sec/m2.
3 2
Equals 345,114 mW-sec/m .
1-18
-------
value and a weighted value (see next section) close to the calculated one.
2
This was the scan at 1432 hours with a total flux of 7.667 W/m irradiance.
As a further point of reference for April 28, 1977, the 1236 hr. EST scan
was plotted. Ths UV-B portion of the spectrum was 7 m?_nutes after the sun
had passed the meridian and was at 17.4 from Zenith. Fig. 4 demonstrates
the calculated total flux of the solar reference day and weighted flux when the
curve is extrapolated to cover irradiance from dawn to dusk. Table 9 is the
accumulated irradiance by nm of wavelength from 0705 to 1402 hrs Est. for
April 28, 1977.
Rating 280 to 320nm for Biological Effectiveness
Because of the high reactivity of the 280-320 nm wavelength radiation
with biological materials, attention has been given to determining the proper
function to apply to have equal effectiveness in a dose-response analysis of
a biological reaction in this spectral region. We have found that the
"weighted function" described by the following formula as "curve fitted" to
a DNA absorption spectra, had good utility for our research.
- - ,~ ,2
y = e ; x= rH-) ;
Then: ? - -(* -ff5 )2 '
e
This was a "weighting function" suggested by Cams eฃ al. (1977) at an EPA/USDA
sponsored workshop at the USDA/ARS Laboratories, Beltsville, MD in Feb. 1977,
and will be referred to as A ฃ21. It was agreed that this would be a portion
of the protocol for this one-year, short-term study. As will be recognized by
biologists, this formula is based on a Poisson distribution.
In many biological phenomena, the responses noted can be described by a
mathematical expression known as the Poisson Distribution. With rare kinds of
events occurring and the 11 is large, the binomial distribution is noticeably
-------
I
ro
O
0700
(295 - 340 ;nm)
o 10
:
-------
Table 9. Total solar UV-B radiation for each Wavelength from 290 - 340 nm
on April 28, 1977.1
X
290
295
300
305
310
315
329
325
330
335
340
2
mW/m
.247
.615
3.448
22.352
67.507
134.470
200.596
248.732
326.219
397.109
339.665
X
291
296
301
306
311
316
321
326
331
336
2
mW/ra
4.
28.
81.
147.
209.
266.
333.
320.
281
784
965
954
623
559
987
296
356
450
X
292
297
302
307
312
317
322
327
332
337
2
mW/m
1.
7.
37.
97.
159.
214.
297.
334.
318.
357
123
245
177
936
609
346
419
585
272
X
293
298
303
308
313
318
323
328
333
338
2
mW/m
.450
1.179
11.179
46.986
111.457
171.37
220.434
304.282
331.361
325.757
X '
. 294
229
304
309
314
319
324
329
.334
339
mW/m
.533
2.267
16.135
56.087
122.067
186.611
230.912
315.030
329.629
328.020
v 2
'"Daily Means for Each 290 to 340 nm expressed inroW/m from 0805 - 1502 hrs EST.
1-21
-------
skewed and the normal approximation is unsatisfactory. Poisson's Distrib-
ution, a limited form of the binomial distribution, is a better approximation
when n tends to be infinite and _p_ tends to be zero at the same time in such
a way that ju = np is constant. This seems to describe the events occurring
with UV-B radiation and plant tissues, particularly if the targets are large
molecules and are repairable or replaced. The Poisson distribution can also
be developed by reasoning quite unrelated to the binomial. It is analagous
to the classical example where signals are being transmitted and the prob-
ability that a signal reaches a given point in a small time-interval t is
>it, irrespective of whether previous signals arrived recently or not. Then the
number of signals arriving in a finite time interval may be shown to follow
a Poisson Distribution.
This formula for comparing biological effectiveness and for matching
natural solar irradiance to experimental test conditions has had good utility
for the following reasons:
1. It is a functional analytical equation that has found much application
in analyzing environmental factors as related to plant responses.
2. To the present time, action spectra of specific biological responses
in this region of the spectrum have been shown to require some adjustments
with most weighting functions. Even the one specifically designed for ery-
thema has to be modified for specific cases of "redding". Figure 5 is a login
plot of the nummerical biological effectiveness factors vs wavelength of several
well described ones. Note the relationship of AS 21 to the others and its pos-
ition somewhat as an "average".
3. This mathematical treatment of biological effectiveness is based on
DNA absorbtion. DNA is the basic cellular molecule
that is the pivotal point for cellular damage by UV-B radiation. There are
1-22
-------
Figure 5
1.0
GREEN AND MILLER
O.I
o
K
O
O
.01
.001
CALDVYELL
(see Nachtwey)
290
295
300
305 310
X (nm)
315
320
Fig 5. Comparison of biological effectiveness "weighting" of UV-B
radiation by several investigators. The AZ21 was used in
this report (see references for otherq)
1-23
-------
other reactions but this component will more than likely play a role in most
plant systems. It is a point of reference and the mathematical interfacing
to biology is fairly straightforward with a seemingly sound logical basis when
compared to other biological events with statistical probabilities.
The data in Table 10 demonstrates the use made.of the A ฃ 21 for biological
weighting. The measured irradiance at each wavelength from 290 to 340 nm at
1432 hours on April 28, 1977 is multiplied by the e~X to yield a biological
2
"weighted" mW/m , illustrated by the last column. To give some utility to
use of the biological effectiveness weighting for establishing experimental
conditions to test the effect of UV-B radiation on plants, a standard refer-
ence condition had to be chosen. We chose to analyze one clear day during
the growing season at Gainesville FL and to use this in addition to other
factors in arriving at a solar reference condition. Figure 3 demonstrates
measured solar irradiance at 1236 and 1432 hours and an "average" calculated
spectral scan for 290 to 340nm. The "average" was based on solar irradiance
2
of approximately 7.08 W/m x
-------
Table 10. Solar radiation at ground level as measured
with a gamma spectroradiometer on April 28, 1977 at 1432
hr at Gainesville, Florida
X
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
0.242
0.217
0.192
0.170
0.150
0.130
0.113
0.098
0.085
0.073
0.062
0.053
0.045
0.038
0.032
0.026
0.022
0.018
0.015
0.012
0.010
0.008
0.007
0.0054
0.0043
0.0034
0.0027
0.0022
0.0016
0.0013
0.0010
0.00082
0.00063
0.00049
0.00037
0.00028
0.00022
0.00016
0.00012
0.00009
0.00009
0.00005
0.00004
0.00003
0.00002
1.5x10 *
1.1x10"^
0.8x10";?
0.6x10
0.4x10"^
0.3x10
mW/m
0.2
0.3
0.3
0.5
0.5
0.6
0.8
1.1
1.4
1.9
2.9
4.3
6.6
10.1
15.0
20.7
27.2
35.1
44.9
54.6
65.3
80.8
97.9
112.9
124.8
138.2
151.1
163.7
176.8
193.7
208.0
219.2
224.5
230.2
2.38.9
256.7
282.8
309.5
318.2
329.7
343.4
351.2
354.5
350.7
. 346.9
345.3
338.5
337.6
343.7
346.3
359.3
WtmW/m2
0.0484
0.0651
0.0576
0.0850
0.0750
0.0720
0.0904
0.1078
0.1190
0.1387
0.1798
0.2279
0.2970
0.3838
0.4800
0.5382
0.5984
0.6318
0.6735
0.6552
0.6530
0.6464
0.6853
0.6297
0.5366
0.4699
0.4080
0.3601
0.2829
0.2518
0.2080
0.1800
0.1414
0.1130
0.0883
0.0718
0.0622
0.0495
0.0382
0.0297
0.0309
0.0176
0.0114
0.0105
0.0069
0.0036
0.0034
0.0027
0.0002
0.0002
0.0002
1-25
-------
irradiance for the day but to modify the reference spectrum on the basis of
solar angles of approximately 50 for the AM and 45 for the PM from the
zenith. The rational was that a certain level of UV-B irradiance was bene-
ficial. There is no a priori basis for choice of this level. We chose to
-3
use the point where the irradiance level at 300nm was approximately 1 x 10
W/m2.'
When the solar reference conditions of the UV-B solar spectrum is
seu
compared to Bener's measurements to approximate a 0.32 atms ' cm ozone column
and Green et^ _al. (1975)mathematical model based on Bener's measurements, it
matches within + 5% the curve descriptive of a 0.32 atms cm ozone column
with a solar zenith angle of 30 . This is illustrated by Fig. 6 and Table
11. Applying the same rules to this curve as to the solar reference spectrum,
2
the total flux from 295 to 340 nm is 7.24 W/m with a weighted flux of 11.52
W/m2. ;
2
Based on these comparison's, the empirically arrived at 11.12 W/m was
used to adjust FS-40 Westinhouse"sum Lamps" and filters for enhancement level.
In studying the biological effectiveness curves (Fig. 5) and the attenuation
of UV-B radiation by ozone, the major atmospheric attenuator, (Fig.7 and8),
it becomes obvious that the critical factor in establishing conditions for UV-B
experimentation is the level of 290 to 300nm radiation. Notice the change in
slope of the 297.5 vs the 320 nm radiation. Adjusting distances to a rad-
iating source along with changing attentuation with filters is the method
used in this study with particular care to filter attenuate for this is a most
critical factor. The "biological effectiveness weighting" is a mathematical
adjustment between what can be accomplished .with lamps, pulleys, filters and
Timers and what is natural or what is expected. '
1-26
-------
0
10 F
16'
Figure 6
10"
I63
10'
'E
c
CJ
I -
id"6
10"
10"
1.0
id1
10"
I6
3
o
H
x-4
10
10"
10
r6
280 300 310 320 330
WAVELENGTH (nm)
340
Fig. 6. Downward global flux for an ozone thickness of 0.32 cm. All points ;r
except the XX are Bener's (1972) results for solar zenith angles
of 0, 30, 50, 70, 80, and 85ฐ in order of decreasing magnitude of
: , the fluxes. The solid lines are the corresponding theoretical
calculations of Shettle and Green. The X points and dotted line
are the reference solar spectrum (see text) and the solid line
referenced to the weighted function is the A Z 21 described in the text.
1-27
-------
Figure 7.
10ฐ
10
-I
CM
2
10'
I0~3200
320
305
300
240 260
OZONE CONC.
280
-3
(X 10
300
Atms cm )
320
340
360
Fig. 7. Solar UV fluxes as adapted from Bener's data, based on attenuation by
various ozone depths. The units are W/m^ at the designated nm.
1-28
-------
Figure 8
10'
,62
CM
I
io3
io4
310 nm
-300 nm
I
295 nm
16 20 24 28 32 36 40
OZONE THICKNESS (ATMS- CM)
4 4 /
Fig. 8. Solar UV fluxes based on Green evt al.'s (1975) analytical treatment
of Bener's data. The units are W/m^at the designated.nm of wavelength.
1-29
-------
TABLE 11.Global UV Radiation at a Solar Elevation Angle of 60ฐ as a
Function of Wavelength for Ozone Thicknesses of 0.32 cm.
(From Shettle and Green, 1974).
Wavelength
(nm)
340
330
325
320
315
310
305
300
295
290
285
280
0. 32-cm ozone thickness
Global radiation
W
m . nra
6. 40x10" 1
4.99X10"1
4. 15x10" 1
3.19X1Q-1
2. 13x10" !
l.lOxlO"1
3.63xlO~2
5. 20x10" 3
1. 63xlO~4
3.06xlO~7
3.16xlO~12
2.10xlO"21
1-30
-------
Establishing Conditions for UV-B Radiation Enhancement In
Controlled Environmental Chambers, Greenhouse and Field Experimentation
The basic arrangement for UV-B radiation enhancement was to use FS-40
Westinghouse fluorescent "sun lamps" with a filter of 0.005 mil (0.20 mm
Mylar, type S, for the control and different thicknesses of cellulose acetate
to simulate different solar equivalent conditions. The irradiative nature
of the FS-40 lamp has been well characterized and illustrations of spectral
output (Fig. 9) and aging (Fig. 10) are included for reference.
A very critical parameter for UV-B radiation enhancement is the use of proper
filters to attenuate the spectral distribution of UV-B radiation. Fig. 11 will
demonstrate the cut-off characteristics of different thicknesses of cellulose
acetate. The films were purchased from Transilwrap, 2616 McCall Place, At-
lanta, GA 30340 in thousand-foot rolls to lessen problems inherent with dif-
ferent lots of film. Using the absorption properties of the different thick-
nesses of cellulose acetate in conjunction with distance from one to several
lamps a given UV-B was established for the enhancement conditions. Table
seu
12 demonstrates typical UV-B conditions in "C" type environmental control
seu
chambers at the Duke University Phytotron with 4 FS-40 lamps at equal distance
but with different mil thicknesses of cellulose acetate. Figure 12 demon-
strates the relation between distance to a 5 mil cellulose acetate filtered
FS-40 lamp and irradiance when it is totalled on the basis of 290 to 320, 290
to 340, or 295 to 340nm
The most practical protocol to use at the present time with our present
level of technology of measuring spectra in the 290-320nm region and sources
of irradiance with filter combinations is to use a radiometer for monitoring
that is periodically calibrated against a well calibrated spectroradiometer.
1-31
-------
Figure 9
10
10
-cj
10
10
290
300
310
X
320
330 (nm) 340
10'
Fig. 9. UV-B irradiance from 2 FS-40 Westinghouse "sun lamps" filtered by 5
mil Cellulose Acetate. The distance to the lamp + filter combination
was adjusted to yield close to 1 UV-Bseu(7.08W/m2 with a weighted value
.of 11.12mW/m2) vs_ 0.747W/m2 with a weighted value of 11.10mW/m2.
-------
Figure 10
10.0
1.0
O.I
0.01
Fig. 10.
3 MIL
2 FS40 LAMPS + 3 MIL C.A. (6 HRS.)
(CM)
10 20 30 40
J 1_ I I
50
I
60
L_
Relation of UV-B irradiance 'to distance from 2 FS-40 "sun lamps"
filtered with 3 mil cellulose acetate as a result of solarization
of the film in 6 hrs. The top curve is C.A. non-exposed; the
bottom exposed 6 hrs. Each data point is total UV irradiance from
290-340nm .
-------
Figure 11
10
-I
10
-2
-3
10
Fig. 11.
B
H
ฉ""v
/ /
/P P
ฉ7 / 003 MIL
If I ,' ' 005 MIL
// D
9 I D D 10 MIL
D/ /
" B B MYLAR
10
a
B
B
a
B
a
290
300 X (nm)
3Iฐ
320
Relation of filters and thickness to UV irradiance at each A' from
285 to 320nra from 2 FS-40 "sun lamps" with all conditions the
same except changing the filters.
1-34
-------
Figure 12
2.0
1.8
1.6
1.4
1.2
1.0
0-9
0-8
0.7
0-6
0.5
0.4
0.3
0.2
O.I
290~320nm
290-340 nm
295-340 nm
o
I
10
20 30
2 (CM)
40
50
Fig. 12. Relation of total UV irradiance from either the 290-320nm, 295-340nm or
290-340nm band-width from 2 FS-40 "sun lamps" filtered with 5 mil
cellulose acetate. 1-35
-------
In addition to knowing the amount of error inherent with the measuring instru-
ments against standard irradiance sources, the comparative calibrations have to
be done under the system that is used to irradiate the organisms, i.e. in the
field in each controlled environmental chamber, and for each greenhouse lab-
oratory set-up. Ideally, monitoring with a spectroradiometer would be best
but availability, economics and convenience are all limiting factors. The
latter is very much related to time involved in obtaining measurements and
maintaining precision in measurements.
Controlled Environmental Chambers
Use was made of both the Gamma Scientific 2900 and Optronics 741 spectro-
radiometers and the Optronics 725 and the sun-burn radiometers in establishing
conditions in the "C" type, reach-in controlled environmental chambers at
the Duke University Phytotron. For the UV-B radiation enhancement portion
of irradiance, the best arrangement found was the mounting of 4 FS-40 West-
inghouse "sun lamps" directly in the chambers (Appendix 1-5). Because of the
high reflectivity of the side walls of the chambers which are constructed
of special-treated, highly polished aluminum, there was good distribution of
irradiance flux in the chambers. This can be ascertained from the data of Fig.
13 and 14. Table 12 contains the data for rating the chambers as to UV-B solar
equivalent values on the basis of measured .UV-B . For ease of keeping up
with the data, the treatment of UV-B levels were given a code of 0,1,2,3,
seu
4, and 5 for mylar, 0.5, 1.0, 1.5, and 2.0 UV-B level of irradiance. Actual
S6U
levels are shown in.the table for each chamber. The photosynthetically active
radiation portion of the spectrum was produced by a bank of 15 cool white
fluorescent lights in combination with 6 incandescent lamps.
In addition to the regular practices of fertilizing once daily with a
half-strength Hoagland's solution and watering with distilled water, normal
1-36
-------
Figure 13
>
E
70
60
50
40
30
20
10
J_
I
J_
. 50
Rsor
Left
40 30 20 IO
0
CN
10 20 3O
40 SO
Front
Right
60
Fig. 13. Relative UV-B irradiance in the "C" type controlled environment
chambers at the Duke Phytotron with 4 FS-40 sun lamps. Upper
curves were measured with 4 lamps ( ฎ "^left to right,centered
front to rear), lower curves are with' 2 lamps (Q;^6^ to r
centered front to rear). .
1-37
-------
Figure 14
75
70
65
E; 60
55
JL
JL
_L
25 30 35 40
Disfonca (cm! 3ulb to Di'fusor
50
Fig.'14. Relative UV-B irradiance with distance of 4 FS-40 sun lamps^
in the "C" type controlled environment chambers at the Duke
Phytotron. Note the change in slope at 40cm as distance to
lamp is increased due to wall reflectance.
1-38
-------
Table "12. Relationship between Gamma Scientific Spectroradiometer and
Optronics 725 radiometer readings and actual UV-B in the Duke
University Phytotron controlled environment "C" chambers.
Chamber
No.
4
9
15
17
7
8
6
10
13
16
1
2
12
18
3
5
11
14
UV-B
seu
Code
0.
0.
1.
1.
1.
1.
1.
1.
1.
1.
2.
2.
2.
2.
0
0
0
0
5
5
0
0
0
0
5
5
5
5
0
0
0
0
FS-40
Filter
Mylar
Mylar
Mylar
Mylar
10+102
10+10
10
10
10
10
3+5
3+5
3+5
3+5
5
5
5
5
Actual
WTJ
o
seu
0
0
0
0
0
0
1
1
1
0
1
1
1
1
2
2
2
2
.036
.007
.003
.005
.496
.536
.12
.01
.07
.99
.46
.57
.47
.59
.05
.08
.16
.09
Gamma Scientific
Wavelength mW/m Optronics
295
0.
0.
0.
0.
0.
0.
2.
3.
2.
2.
5.
5.
4.
8.
6.
10.
10.
10.
15
00
00
00
46
46
50
09
60
80
30
10
80
18
50
50
40
20
300
0.07
0.00
0.00
0.00
3.50
3.20
8.60
7.20
8.30
7.40
10.40
11.40
11.30
11.70
15.10
15.40
15.60
15.30
310 725 Value
0.
0.
0.
0.
2.
2.
3.
2.
3.
2.
3.
3.
3.
3.
4.
4.
4.
4.
00
00
00
00
02
00
20
70
10
80 .
70
90
80
30
20
40
60
30
0.6
0.6
0.6
0.6
2.4
2.8
4.6
6.4
6.8
5.8
4.9
7.0
7.7
5.5
6.2
7.6
Mylar, Type S, .005 mil.
Cellulose acetate, numbers designate mil thickness
1-39
-------
chamber maintenance and procedures were followed.
UV-B irradiance and PAR light during the photoperiod were continuously
monitored by a radiometer coupled to a strip chart recorder for each chamber.
Filters were changed after 18 hours of exposure to radiation from the FS-40
lamps to lessen the problems associated with solarization of the filters.
Conceptulization of the physical condition for plant treatment can be aided
by viewing photographs in Appendix 1-5, 23).
Greenhouse Irradiator
As with establishing the conditions for UV-B enhancements in controlled
environmental chambers, spectroradiometers were used to measure irradiance at
set-up and initiation of the experiment, at periodic check times and at the
time of termination of each experiment. Routine monitoring was accomplished
by use of the Optronic 725 radiometer. Filter changes and lamp checks were
made after each 18 hours of burn-time on the FS-40 lamps. Protocol was estab-
lished to keep total weighted UV-B radiation within + 10% in between the
filter changes and lamp checks by raising and lowering the bank of lamps. The
arrangement on the greenhouse irradiators at the Duke University Phytotron and
at Gainesville FL can be seen in photographs on pages 1, 35 and 37 of Appendix
I. In addition to movement of the bank of lamps up and down by pulley arrange-
ment, each lamp could be moved laterally independently of other lamps. This
allowed lateral adjustments in any direction to help establish an irradiance
flux within specified levels.
1-40
-------
The Field UV-B Irradiator
The irradiator for the field was basically a single aluminum reflector
20 meters in length with 6 x FS-40 Westinghouse "sun lamps" mounted end to
end. A special highly posished aluminum reflector was extruded as a single
crimped piece with cross-sectional dimensions as shown in the following
diagram:
The one-cm fold on the sices allowed a place for attachment of the cellulose
acetate films. Txvelve of these units were built and mounted over specially con-
structed beds in the field (see Section IV for description of the plant beds,
irrigation system, and control of the field area). The reflectors were rein-
forced on the side opposite the lamps by a single strip of 2.5 x 2.5 cm alum-
inum channel. The lamp base was chosen because of its small size and having
a self-contained transformer of the rapid start type. These lamp fixtures
were mounted on the underside of the reflector and the depth of base plus
lamp was 7.8cm. The design was to give a single line source of irradiance.
The reflector/lamp combinations were mounted on pulleys and chains (Appendix
1-1) at each end and the center so height adjustments could be made as the
plants grew. A UV-B irradiance gradient was established by maintaining a 12
angle on the irradiation unit. Filters were changed, lamps checked and ir-
radiances measured on the gradient twice a week, namely Monday and Thursday.
During the growing of the first 3 crops of tomatoes, potatoes and corn,' the
gradient was established using 5 mil cellulose acetate filters and lamp heights
to yield a 0.8 UV-B level at mid-lamp on the first meter to less than 0.02
SGV1
1-41
-------
UV-B at mid-lamp on the lowest enhancement meter. During the growing of the
seu
second three crops of Southern pea, 'Florunner" peanuts and upland rice, 'Star
Bonnet1, the irradiance gradient was from 1.5 UV-B at midpoint of the first
& seu v
lamp at the highest enhancement level to less than 0.02 UV-B at midpoint of
the meter under the lowest enhancement level. For crops of squash, mustard
and 'Red Globe' radish, the filter material was changed to 3 mil cellulose
acetate and the gradient from 3.1 UV-B to 0.02 UV-B . An example of the
seu seu
measured gradient for these three crops is shown in Fig. 15. The gradient for
the other crops had a similar shaped curve but at lower UV-B irradiance levels.
Literature Cited
1. Bener, P., Approximate values of intensity of natural ultraviolet radiation
for different amounts of atmospheric ozone, Final report, European Research
Office, U.S. Army, London, 1972.
2. Berger, D., D.F. Robertson, R.E. Davies. 1975. Field measurements of
biologically effective UV radiation. Climatic Impact Assessment Program
Monograph 5, Part 1 2:233-264.
3. Cams, H.R., R. Thimijan and J.M. Clark. 1977. Outline of Irradiance
distribution of UV fluorescent lamps and combinations. Symposium on
Ultraviolet Radiation Measurements for Enviornmental Protection and Public
Safety. June 8-9, 1977. National Bureau of Standards, Gaithersburg, MD. 3pp.
4. Green, A.E.S., T. Sawada and E.P. Shettle. 1974. The middle ultraviolet
reaching the ground. Photochem. Photobiol. 19: 251-259.
1-42
-------
3X 10'
10
,-2
CONTROL
METER
J 0.70
0.50
. 0.20
METERS ALONG BEDS
Fig. 15. An actual measured UV-B irradiance gradient in W/m (Z 295-340nm) at plant height down the
planting bed in the field irradiator. This was the gradient used for squash, mustards and radish,
-------
, IL, . , _ K. , , u., j.i.
5. Green, A.E.S., T. Sawada and E.P. Shettle. 1975. The middle ultraviolet
reaching the ground. Climatic Impact Assessment Program Monograph 5,
Part 1 2: 29-49.
6. Nachtwey, D.S. 1975. General aspects of dosimetry. Climatic Impact
Assessment Program Monograph 5, Part 1 2: 49-60.
7. Rupert, C.S. 1974. Dosimetry concepts in photobiology. Photochem.
Photobiol. 20: 203-212.
8. Setlow, R.B. 1974. The wavelengths in sunlight effective in producing
skin cancer: a theoretical analysis. Proc. Nat. Acad.Sci. U.S.
71: 3363-3366.
1-44
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EFFECTS OF ULTRAVIOLET-B RADIATION
ENHANCEMENTS ON EIGHTY-TWO
DIFFERENT AGRICULTURAL SPECIES
Abstract
Eighty-two different agricultural species were grown for 4 to 11 weeks in
growth chambers at the Duke University Phytotron under 4 to 5 different UV-B
irradiance regimes. Twelve replicates (plant/pot) for each species for each
chamber were repeated in 2 or 4 chambers (plots) and data taken for each repli-
cate included: 1) leaf fresh and 2) dry weight, 3) stem fresh and 4) dry
weight, 5) root fresh and 6) dry weight, 7) leaf area, 8) leaf density 9) root:
shoot ratio 10) total fresh and 11) dry weight biomass 12) % leaves, 13) %
steins and 14) % roots. Monocots were measured weekly for height and at harvest
the total number of leaves, number of chlorotic leaves and % chlorotic leaves
was determined.
The most universal response to UV-B irradiation was dwarfing, a stunting
of plant organs and shortening in stature. Other effects included marginal
and interveinal chlorosis, concave and convex leaf cupping, leaf wrinkling,
red pigment formation, darker green color of leaves, epinasty of leaves,
lessening of vine characteristics and loss of apical dominance.
Each species was treated for response to UV-B radiation as indicated by
the leaf, stem and root dry weight increases or 'decreases when compared to
the controls; Sixteen were favored, showing increase in biomass, 10 were
resistant, biomass being ฑ 5% of the controls, 24 were moderately susceptible,
showing 5-25% decrease in biomass, 15 were sensitive, showing 25-50% decrease
in biomass and 17 were highly sensitive showing greater than 50% reduction in
biomass. The Gramineae tended to be the most resistant or favored and the
Cruciferae were the most highly susceptible. Leaf density increased on favored
II-l
-------
and resistant species. Biomass partitioning shifted to a larger % in leaves
at the expense of stems and roots for dicots but the pattern was not strong in
the Gramineae where it was often the reverse of this. Conifers were moderately
susceptible but leaf density was altered by the UV-B enhancement levels used.
II-2
-------
Introduction
To evaluate young seedling response and vigor to enhanced levels of UV-B
radiation, 82 different agricultural species and varieties were grown for 4
to 11 weeks in growth chambers at the Duke University Phytotron (Table 1).
There included 42 vegetable, 30 agronomic and 7 forest crops.
Materials and Methods
The plants were grown and treated in 18 "C" chambers with highly reflective
polished aluminum walls (Appendix 1-5). In each of 4 chambers per UV-B light
regime the soil surface was set at the appropriate distance from cellulose
acetate or mylar filtered FS-40 Westinghouse sun lamps to obtain a UV-B irradiance
approximating 0, 0.5, 1.0, 1.5 and 2.0 UV-B as described in Section I of
S cU
this report (Table 2). With 4 FS-40 lamps in a "C" type chamber filtered with
5 mil cellulose acetate at a distance of 60 cm from plant height, the weighted
2 2
11.12 mW/m equalled 0.71 W/m of unweighted flux, A bank of 15 cool white and
4 incandescent lights in each chamber maintained a 16-hour photoperiod of
-2 -1
approximately 200 microeinsteins m sec . Photosynthetically active radiation
2 1
was measured in microeinsteins m sec with and without the FS-40 lamps (Table 2).
UV-B irradiance was measured with a Gamma Scientific spectroradiometer equipped
with a solar blind filter. Irradiance levels are expressed as UV-B x^here 1
seu
22
UV-B under FS-40 lamps equal a weighted flux of 11.1 mW/m . Daily UV-B
S GU
radiation from the filtered FS-40 lamps was for a 6-hour period in the center
of the 16-hour photoperiod. Mylar and cellulose acetate of 10+10 mil, 10 mil,
3+5 mil, and 5 mil filters (TransiLwrap Comp., 3616 McCall Place, Atlanta, GA
II-3
-------
30340) were used in combination-with height adjustments on the FS-40 lamps to ob-
tain the appropriate UV-B levels (Table 2). Filters were changed every 3 to 4
days. Only 2 chambers were available for 0. 5 UV-B but 4 chambers were used
3 J . seu
for the other treatments. '
In the first series of tests, the temperature in 10 of the chambers, 2 for
each of the 5 light regimes, was programmed for 19ฐ during the day and 15ฐ for the
8-hour dark period. Twenty-one species were grown in these chambers (Table 1).
In the remaining 8 chambers, 2 for each UV-B irraidance regime, omitting the 0.5
UV-B/ trt. The temperature was programmed for 21ฐC day and 17ฐC night. Twenty
seu
two species were grown in these 8 chambers. In the second series of tests all 18
chambers were used and 39 species grown under a 26ฐ/22ฐC day/night temperature re-
gime. For each species, 12 pot replications were made, 6 per chamber in the first
series of tests (chamber replicates for each UV-B irradiance regime) and 3 per cham-
ber in the second test series of 4 chamber replicates per irradiance regime.
Six to 12 seeds were planted in each pot which was 7 cm in diameter and
325 ml .in volume. The potting mix was a gravel/vermiculite standard medium.
This media was chosen because of past successes of getting good germination
and because it could be removed from the roots of the plant easier than most.
Plants were watered twice daily with a modified half-strength Hoaglands solution.
After germination, the dicots were thinned for uniformity to 2 plants per pot.
Nineteen different parameters were evaluated on the plants in the present
study. Height was measured on each monocot plant and a Duncan's Multiple Range
test made on the data taken after 2 (Table 3, 4). 3 (Table 5, 6) and 4 (Tables
Seed of various species were contributed by the Florida Seed Foundation, Tallahassee,
Weyerhauser Company, Centralia, Wash., Agricultural Seed Laboratory, Phoenix,
Arizona and other seed was purchases locally. We thank the various suppliers for
their immediate help on this one-year project.
II-4
-------
7, 8) weeks. At harvest, the monocots were evaluated for total number of
leaves (Tables 9, 10), number of chlorotic leaves (Tables 11, 12) and % of
leaves showing chlorosis or tip burn (Tables 13, 14) and a Duncan's Multiple
Range test run on the 12 pot means for each UV-B irradiance. Dicots were
evaluated for chlorosis and other visual symptoms. .
After the final height measurements and non-destructive evaluations were
made, all 82 species were harvested on a container (pot) basis and a Duncan's
Multiple Range test for significant changes and rankings was made on data for
each measured parameter. Data taken for each pot included: 1) leaf fresh
weight, 2) stem fresh weight, 3) root fresh weight (roots water washed and all
vermiculite removed), 4) leaf dry weight (Tables 15, 16), 5) stem dry weight
(Tables 17, 18), 6) root dry weight (Tables 19, 20) 7) total dry weight biomass
(Table 21, 22), 8) % leaves (Tables 23, 24), 9) % stems (Tables 25, 26), 10)
% roots (Tables 27, 28), 11) leaf area (Tables 29, 30), 12) leaf specific
thickness or density (Tables 31, 32), and 13) rootishoot ratio (Tables 33,
34). A photographic record was made of each species grown under each UV-B
irradiance regime (Appendix 1-6 to 22). Six sensitivity ratings were used
for evaluating each species. These were based on leaf, stem and root biomass
production in relation to control plants. Species with increases in biomass
were rated as "favored" (+) and those showing ฑ 5% biomass changes were classified
as "resistant" (0). Species with biomass reductions of 5 to 25%, 25 to 50%
and 50% or greater were classified as moderately susceptible (1); susceptible
(2) and highly susceptible (3), respectively.
Increases or decreases in leaf density from the Mylar control were grouped
as 0-5%, 5-10%, 10-15% and 15-20%. Changes in % leaf bioraass partitioning were
grouped as 3-10%, 10-15% etc., increasing by 5% increments. Percent root
increase or decreases from the control were highly variable and grouped 0-25%,
11-5
-------
25-50% and 50-75%, increasing by 25% increments.
Individual parameters for each species and the relevant statistical analyses
can be found in Tables 3 to 34 and should be referred to for detailed study.
Results
1- Cruciferae - Appendix 1-6,7,8,9,101
All but 2 of the crucifers (mustard and radish) were rated as highly suscep-
tible (Tables 35, 36). At 1 UV-B the mustard was moderately susceptible but
S>U
at 1.5 or 2.0 it was highly susceptible. The radish was favored at 0.5 and 1.0
UV-B , showing increases in biomass. It was moderately susceptible at the
S ฃ11
other enhancement levels. The crucifers showed pronounced concave leaf cupping,
leaf wrinkling, marginal chlorosis, stunting and reduction in leaf .area. Leaf
density was decreased in broccoli, kale and kohlrabi.
While the other crucifers, especially mustard and rutabega, increased in
leaf density (Tables 31, 32). Biomass partitioning was not altered in brussel
sprouts and slightly increased in leaves and stem for mustards. Radish showed
the most increase in partitioning into the vegetative portion (up to 25% more
than the controls), and broccoli was in the 10-15% increase groups. The other
crucifers partitioned 3-10% more biomass into the vegetative above ground portions
of the plant. The 3-10% increases for leaf and stem biomass were accompanied
by % decreases in root biomass of 25-50% or more, and even the radish and
mustard were lower (Tables 23-28).
II. Chenopodiaceae - Appendix 1-7.
Chard in this experiment was very susceptible (Tables 35, 36) in biomass
These Appendices referals are for the photographic records.
II-6
-------
.I.. ..-J....I,
reductions (Tables 21, 22) but the % leaf and stem dry weight was unaltered
(Tables 23-26). Visual symptoms were the. same as in the crucifers. Percent
root allocation was variable but increased under 1 and 2 UV-B and decreased
seu
under 1.5 (Tables 27, 28). Leaf density increased an average of 9% over that
of the control (Tables 31, 32).
III. Compositae - Appendix 1-1,8,22
Artichoke and sunflower were favored by UV-B radiation while lettuce was
moderately susceptible (Tables 35, 36). Sunflowers appeared fairly normal and
the artichoke, being slow to germinate, also appeared normal except for the
slightly smaller size. Leaf density was decreased 15-20% for artichoke and
lettuce and 10-15% on sunflower (Tables 31, 32). The biomass found in leaves
and stems was increase 3-10% in lettuce and sunflower but was down 10-15% for
artichoke (Tables 23-26). Correspondingly, root biomass was increased in arti-r
choke and sunflower but decreased 15-20% in lettuce (Tables 27, 28).
IV. Cucurbitaceae - Appendix 1-12,13
Only watermelon and early summer squash were rated highly susceptible in
this family (Tables 35, 36). Pumpkin was moderately susceptible and the other
cucurbits were susceptible. Stunting and interveinal chlorosis were found as
well as convex cupping of the leaves. In general leaf density decreased, up to
10% but early summer squash leaf densities decreased to 32% (Tables 31, 32).
Cucumber leaf density increased to 29% and watermelon to 46%. Biomass parti-
tioning into leaves was markedly increased in the cantelopes and squash Cup
to 51% for both) but somewhat less in pumpkin (up to 14%) and watermelon (up
to 28%) (Tables 23, 24). Percent biomass in stems was decreased 35-40% in the
squash, 44-53 in the melons, 40% in cucumber, 37% in watermelon and 10% in pumpkin
(Tables 25, 26). The decrease in root biomass was also high for honeydew
II-7
-------
cantelope (up to 43%) and cucumber (up to 50%) with the other species showing
less reductions (Tables 27, 28).
V. Gramineae - Appendix 1-17, 18
Pensacola, Bahia, Bermuda and Carpet grass were susceptible to moder-
ately susceptible (Tables 35, 36). Stunting and tip chlorosis were the most
obvious UV-B symptoms (Tables 3-8 and 11-14). Leaf-density increased with
exposure to UV-B radiation (Tables 31, 32) and there was little change in
biomass partitioning for % leaves (Tables 23, 24). Percent roots increased
on Pensacola grass (up to 67% and the others decreased (Tables 27, 28).
Chufas, Sudangrass and oats were favored by UV-B radiation and showed
increases in biomass (Tables 15-22). At least at the lower UV~Bseu regimes,
leaf density was increased for oat and Chufas but decreased on Sudangrass
(Tables 31, 32). No change in leaf biomass partitioning was found, or %
roots on Chufas, but oat and Sudangrass showed variable increases and
decreases in % roots at the different UV-B levels (Tables 23, 24, 27, 28).
Final height was increased to 1-14% in oats, 17% in Sudangrass and 19% in
Chufas (Tables 7, 8). Up to 45% and 55% increases in leaf chlorosis were
found in Sudangrass and oats, respectively, and 186% in Chufas (Tables
13, 14). However, the total number of leaves was decreased in oats, up to
26%, and increased in Sudangrass, and Chufas, up to 31% and 58%, respectively
(Tables 9, 10). .
Rye and sorghum were moderately susceptible (Tables 35, 36),
showing only small variations in biomass partitioning (Tables 23-28). The
total number of leaves was higher (Tables 9, 10) with a greater density than
the control in rye and the opposite in sorghum (Tables 31, 32).
The two millets were moderately susceptible (Tables 35, 36) with op-
posite responses in biomass partitioning (Tables 23-28) and leaf density
n-o
-------
(Tables 31, 32). Starr Pearl millet had decreased leaf density (Tables
31, 32) and % leaves (Tables 23, 24) but increased % roots (Tables 27, 28).
Both were reduced in height 10-20% (Tables 7, 8), both had increased numbers
of leaves (Tables 9, 10) and increased percentages of the leaves showing
chlorosis (Tables 13, 14). The three barley varieties responded similarly
to UV-B radiation although Hembar was altered more and was rated susceptible
and Belle and Arivat barleys were moderately susceptible (Tables 35, 36).
Leaf density was less for all three (Tables 31, 32). Height was reduced
25-50% below the controls for Belle and Arivat and 50-75% for. Hembar (Tables
7, 8). Increased chlorosis was observed in Belle barley but Arivat and
Hembar barley showed increased chlorosis only for 1 UV-Bseu and decreased
chlorosis at the higher UV-B levels (Tables 11-14). Biomass partitioning
was unaltered in Arivat barley and the % biomass in leaves and stems was
decreased with the % roots increased in Belle and Hembar barley (Tables
23-28).
Corn varieties were susceptible, except Coker 71 which was highly
susceptible, to UV-B radiation (Tables 35, 36). Silverqueen and Hybrid XL
380 corn were resistant to 1 UV-Bg^ but not the other levels. Leaf density
was increased 5-10% in all but the Coker variety which showed a pronounced
decrease in leaf density (Tables 31, 32).. Biomass partitioning did not
change in Silverqueen corn but the % leaves increased in Tobelle and the
Hybrid drastically decreased in the slightly susceptible Coker variety
(Tables 23-28). Percent roots was variable except in the Coker variety
where it increased (Tables 27, 28). Height was reduced 21-30% in Silverqueen
and Coker corn but only 11-20% in the other two (Tables 7, 8). All 4
varieties had over 25% more of the leaves chlorotic and some decrease in
the number of leaves, except for Silverqueen where the numbers were similar
to the control (Tables 13, 14).
II-9
-------
Brazos and LaBelle rice were resistant and Lebonnet ., Bluebett and
Star Bonnet rice varieties were moderately susceptible to UV-B radiation
tlables 35, 36). Biomass partitioning was essentially the same as in the
controls with slight decreases in the % roots of Lebonnet and Bleubet
(Tables 23, 28). Leaf density was highly reduced at all levels for Lebonnet
rice but less so for the others (Tables 31, 32). Height was reduced about
the same % in all varieties, reaching a maximum of 19% at 1.5 UV-Bseu in
Star Bonnet rice (Tables 7, 8). Lebonnet had a decrease in the amount of
leaf chlorosis while the other 4 had increases of 25-50% over than of the
control (Tables 13, 14). Total number of leaves was slightly increased
in Labelle rice, the same in Brazos and decreased up to 15% in the other
3 rice varieties (Tables 9, 10).
VI. Leguminosae - Appendix 1-14, 15, 16, 22.
Beans were all moderately susceptible (Tables 35, 36) with biomass
reductions up to 25% of the controls (Tables 21, 22). Stunting, leaf
wrinkling, release from apical dominance and a lessening of vine characters
were general legume symptoms. Leaf density was increased 11-12% on garden
bean, pinto bean and Tennessee Flat bean, but 78% on Lima bean (Tables 31,
32). Biomass partitioning was the same as the controls for leaves, and stems
except a 17% decrease in stems for the garden bean (Tables 23-26). A slight
increase in root biomass detected in garden and pinto bean at 0.5 and 1.0
UV-Bseu while the rest of the levels had up to 25% decreases in root biomass
(Tables 27, 28). Only Lima beans showed an increase in roots, up to 20%
at 1 UV-Bseu.
*
Butterpea was moderately sensitive (Tables 35, 36) with a large in-
crease (up to 174%) in leaf density (Tables 31, 32). No difference was
11-10
-------
found in biomass partitioning for leaves and stems (Tables 23-26), although
roots showed a decrease of up to 28% (Tables 27, 28). Blackeye peas were
highly sensitive (Tables 35, 36) and also showed an increase in leaf density
up to 27% (Tables 31, 32). Similar amounts of biomass were partitioned into
the leaves as in the controls (Tables 23, 24) but apparently more into steins
with reduction in root biomass (Tables 25-28). English peas were favored by
UV-B radiation at the lower UV-Bgeu, (Tables 35, 36). Leaf density increased
up to 376% above that of the control (Tables 31, 32) and more biomass was
partitioned into leaves (Tables 23, 24) with reductions in roots (Tables
27, 28).
Clover was highly sensitive (Tables 35, 36), with increases in leaf
density (Tables 31, 32) and biomass proportions in leaves (Tables 23, 24).
Partitioning into stems and roots was highly variable but did increase for
roots at the 1.5 and 2.0 UV-Bseu levels (Tables 26-28).
Soybean was susceptible (Tables 35, 36) with up to a 114% increase in
leaf density (Tables 31, 32). Biomass partitioning was not strongly altered
by UV-B radiation and there was some increase in the % roots (Tables 23-28).
Leaf bronzing, chlorosis wrinkling and development of a deeper green leaf
color occurred under higher UV-B ,
6 seu's.
Peanuts were favored by UV-B radiation (Tables 35, 36). There was up
to 6% increase in dry weight (Tables 21, 22) that was apparently due to
increased leaf and stem dry weights (Tables 15-18) because root dry weight
was lower than corresponding controls (Tables 19, 20). Leaf density was
only slightly increased (8%) (Tables 31, 32).
VII. Liliaceae - Appendix 1-21.
- - " - i
Both asparagus and onion were resistant to UV-B radiation (Tables 35,
36). Leaf density tended to decrease for asparagus (Tables 31, 32) and
11-11
-------
there was some increases in percent roots (Tables 27, 28). Onion responses
for most parameters were highly variable UV-B enhancement treatments.
VIII. Malvaceae - Appendix 1-22.
Cotton was resistant to UV-B radiation (Tables 35, 36) and showed
increases in weight of leaves stems and roots at the 0.5 UV-Bseu (Tables
15-18). The plants appeared normal except for red pigmentation along
the petioles. At higher levels biomass was slightly decreased (Tables 21,
22). Leaf density remained similar to the controls (Tables 31, 32) and
there was a slight increase in biomass partitioning into leaves with re-
duction in stems and roots (Tables 23-28). Okra was susceptible (Tables
35, 36), but with no change in leaf density (Tables 31, 32) or biomass
partitioning into leaves (Tables 23, 24). Percent stems (Tables 25, 26)
was increased and the roots (Tables 27, 28) correspondingly decreased under
the higher UV-B irradiance levels.
IX. Pinaceae - Appendix 1-19, 20.
The conifers were moderately susceptible (Tables 35, 36) to UV-B,
with the exceptions of white fir which was favored and Douglas-fir which
was resistant. Leaf dry weights were reduced 8 to 22% and roots 9 to 25%
below the controls (Tables 15, 16). The .effects were less pronounced at
0.5 UV-Bseu. White fir had well over twice as much leaf and root biomass
(Tables 15, 16, 19, 20) as the controls and leaf density was increased 44%
at 1 UV-Bseu (Tables 31, 32). The % leaves was unaltearedby UV-B (Tables
23, 24) and the % roots was increased in slash and loblolly pine and white
fir but decreased 3 to 9% in lodgepole and ponderosa pine and noble fir
(Tables 27, 28). Leaf dry weight increased in Douglas-fir by 7% (Tables
15,16 ) but root dry weights, were variable depending on the UV-B level
11-12
-------
.. -' '*'- I- ''
(Tables 19, 20). Leaf density in Douglas-fir increased by 10% over the
controls (Tables 31, 32). Around 16% less biomass was partitioned into
roots (Tables 27, 28).
X. Polygonaceae - Appendix 1-9.
/~
Rubarb was highly susceptible to UV-B radiation (Tables 35, 36) and
showed increased leaf densities up to 226% greater than the controls (Tables
31, 32). Visual symptoms were similar to the Cruciferae. About 5% more
biomass was in leaves (Tables 23, 24) with corresponding decreases in stem
and root dry weights (Tables 25-28).
XI. Solanaceae - Appendix 1-21.
Bell pepper plants were resistant to 0.5 UV-Bseu (Tables 35, 36), with
a 47% increase in total dry weight (Tables 21, 22). At the higher UV-B level
it had decreases in biomass (Tables 21, 22). Leaf density (Tables 31, 32)
was unaltered and biomass was increased 6% in leaves (Tables 23, 24), 10% in
stems (Tables 25, 26) and decreased in roots (Tables 27, 28).
Eggplant was favored by UV-B at the lower levels (Table 35, 36) and
biomass was not decreased until the 2.0 UV-B treatment (Tables 21, 22).
seu ' '
Leaf density was not altered (Tables 31, 32) and biomass partitioning showed
around 18% increase in leaves (Tables 23, .24) and 5% increase in roots
(Tables 27, 28), but a 28% decrease in stem dry weights (Tables 25, 26).
Tomatoes were highly susceptible (Tables 35, 36). Leaf density was
decreased 10% below the controls (Tables 31, 32). The percent biomass in
leaves was increased 18% over controls (Tables 23, 24) and the stems and
roots decreased 15% and 29%, respectively (Tables 25-28).
11-13
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XII. Umbelliferae
Carrots and celery were favored by UV-B radiation (Tables 35, 36),
showing increases in total dry weight biotnass, especially at 0.5 and 1.0
UV-B for celery (Tables 21, 22). Leaf-stem dry weights (Tables 15-18)
S6U.
as well as root dry weights (Tables 19, 20) were increased. Leaf density
was increased up to 26% for carrots and averaged 22% for celery above the
respective controls (Tables 31, 32). However, an average of 2 to 4% less
biomass was partitioned into leaves in these two species (Tables 23, 24)
with the main increase in the % roots (averaging 14% for carrot and 23%
for celery) (Tables 27, 28).
Parsnip was a resistant species (Tables 35, 36) which did not change
in leaf density (Tables 31, 32). Slightly more (6%) biomass was in leaves
than in roots (Tables 23, 24, 27, 28).
Discussion
Taxonomic groups with some measured component increasing, i.e., dry
weight, as a result of UV-B radiation included 6 different families and 16
species or varieties. An additional 2 families and 10 species were classified
as resistant to UV radiation (Tables 35, 36). For the Gramineae, favored
and resistant species included wheat, oats, rice, chufas and sudangrass.
Within the dicots, favored and resistant species included sunflower, radish,
peanuts, English peas, onion and cotton. Douglas-fir and white fir of the
Pinaceae were also included here. There are 7 species included in these 2
categories which were slow to gernimate and thus, were not exposed to en-
hanced UV-B levels for very long before they were harvested. The seven
were: artichoke, eggplant, carrots and celery of the favored category, and
asparagus, bell pepper and parsnip of the resistant category. Since detri-
11-14
-------
mental UV-B effects at the irradiance levels used are probably cumulative
and were not pronounced after only 1 or 2 weeks of growth, one should be
cautious in interpreting the data for these 7 species.
Except for radish and mustard, the Cruciferae were the most, sensitive
group, followed by Solanaceae, Cucurbitaceae, Chenopodiaceae, Polygonaceae
and some Leguminosae and Gramineae. Tomato was the most sensitive of the
82 species. Biomass reductions on plants for which the leaf or stem are
the marketable product represent direct effects.on yield. Changes in leaf
density may also alter quality of the leafy product. .
Although monocot plants have usually performed better than dicots under
UV-B radiation, the Coker 71 corn was a highly sensitive variety and the
other 3 corn varieties were classified as sensitive. Hence, corn did not
follow the usual pattern for grasses.
In rating the species for sensitivity to UV-B radiation certain family
or generic groups tended to fall within the same rating (Tables 35, 36).
For example, all except 2 of the Cruciferae were highly sensitive and 5 of
the 6 Pinaceae were moderately sensitive. However, in families where
several genera were represented, the genera sorted out into different ratings
and this was sometimes evident for species within genera, although in the
latter case the ratings were not widely diverse.
Leaf density, with few exceptions, increased or stayed the same for
favored and resistant species (Table 36). Species within any given
susceptible category did not follow a pattern for increasing or decreasing
leaf density according to the sensitivity rating. However, within a genus
or family there was often some uniformity in leaf density response. All
11 Leguminosae species and 6 of 7 wheat varieties showed increases in leaf.
density and 7 of 9 Cucurbitaceae showed decreases in leaf density. Each
11-15
-------
genus or species with varieties within the Gramineae also tended to follow
a general pattern of increased leaf density. The leaf density response
then, was consist for plants resistant or favored by UV-B radiation, and
variety, species, genus or family related for those classified in a suscepti-
ble category; i.d. showing decreases in biomass below the control with
exposure to treatment. .
As a general rule, when biomass was reduced, there was a higher %
biomass found in leaves and a lower % in stems and roots, particularly
for the dicots. This shift was not as pronounced in the Gramineae and in
5 of the 7 wheat varieties, the opposite was true, % roots increasing with
% biomass decreasing in leaves and stems. Rice was very stable in relation
to biomass partitioning.
Symptoms of UV-B treated plants grown in controlled environment chambers
under controlled, but low photosynthetically active radiation levels, are
exaggerated examples of what might be observed under field conditions. Star
Bonnet rice, Silverqueen corn, Walter tomato, Florunner peanuts, Red Globe
radish and mustard grown in the field in 1977 were of the same seed lot as
those grown in the phytotron study. Increases and decreases in biomass and
changes in yield, quantity and quality of products were observed under field
conditions. Vegetative changes that would logically affect yields as found
under field conditions were also observed in the phytotron. Leaf chlorosis
and wrinkling symptoms observed in the phytotron were also evident in the
field but to a much lesser extent. Thus, knowledge of symptoms produced
under controlled environment conditions may allow growers of individual
crops to recognize UV-B effects in the field when crops are being grown under
ซ
optimal cultural conditions. Investigators developing vesetrdie\arietLe5 especially
for areas of high natural UV-B flux, may be able to recognize these symptoms
11-16
-------
in various lines they are propagating since vegetables tended to show leaf
effects. However, agronomists and foresters working with Graraineae and
Pinaceae species will have less opportunity to identify sensitive plants
under field conditions since stunting was the major visual symptom in
these families.
However, caution must be taken in extrapolating effects on crop yield
from controlled environment chamber observations as related to UV-B
radiation, especially since photorepair at high PAR levels may show as
much variation as UV-B effects at low PAR intensities. Thus, actual com-
parative analyses, such as underway with some crops, should be done to
verify the effects of UV-B radiation under field conditions. The controlled
environmental chamber testing is invaluable in demonstrating the crops
that are sensitive to increased UV-B irradiance and the type of responses
expected.
11-17
-------
Table l. Species and length of time grown in the "C" chamber at the Duke
Univ. Phytotron under 16 hr photoperiod.and the designated day/night
. temperatures.
19ฐ/15ฐC
Common Name
1. asparagus, 'Mary Washington1
2. carrots, 'gold king1
3. celery, 'golden self-blanching'
4. radish, 'red globe'
5. lettuce, 'iceberg1
6. onion, 'white Bermuda1
7. parsnip, 'long smooth'
8. peas, 'little marvel English'
9. wheat, 'wake!and1
10. wheat, 'Cocorit'
11. wheat, 'Cajeme'
12. wheat, 'Crane'
13. wheat, ' Inia..56R'
14. wheat, 'Jori'
15. wheat, 'Super X1
16. pine, slash
17. pine, Inblolly
18. pine, lodeepole
19. pine, ponderosa
20. fir, noble
21. fir, white
Scientific Name
# Weeks
Asparagus officinal is L 5
Dacus carota. L 5
Apium graveolens L ...5
Raphanus sativus L 4
Lactuca sativa L 4
AVMum cepa I ..4
ฃa_stinaca_ sativa L 5
Pi sum sativurn L 4
Tri ti cum aestivum.. 4.
Triticum spp 4
Tri ti cum spp 4
Triticum spp 4
Triticum spp 4
Triticum spp 4-
Triticum spp 4
Pinus elliottii Enqelm 11
Pinus taeda L 11
Pinus contorta Doug! ..11
Pinus ponderosa Laws 11
Abies procera Rehd. [Abies nobi!
-------
Table 1 Con't.
21ฐ/17ฐC
Common Name
22. barley, 'Belle1
23. barley, 'Arivat1
24. barley, 'Hembar1
25. broccoli
26. brussel sprouts, 'Long
Island Improved1
27. cabbage
28. cauliflower, 'snowball1
29. chard
30. collards
31. kale 'Dwarf blue Scotch'
32. Kohlrabi
33. mustard
34. rutabega
35. corn 'silverqueen1
36. corn 'Tiobelle1
37. corn, hybrid XL 380
38. corn, 'coker 71'
39. grass, 'Pensacola1
40. grass, 'Arg.. Bahia1
41. grass, 'Bermuda1
42. grass, 'carpet1
43. soybean, 'Hardee'
Scientific Name
# Weeks
Hordium vulgare L 4
Hordium vulqare L 4
-Hordium vulgare L 4
Brassica oleracea L. var. botrytis 4
Brassica oleracea L. var. geriirnifera 4
Brassica oleracea L.
Brassica Oleracea L.
Beta vulqaris L. var
Brassica oleracea L.
Brassica oleracera L
Brassica oleracera L
var.
var.
cicia
capitata 4
italica 4
4
Brassica
juncea
var. acephala 4
var. acephala 4
var. gongylodes.,.4
var. crispifolia 4
Brassica napobrassica (L.) Mill. 4
Zea_ may_s_ L. var. saccharate 4
Zea Mays L 4
Zea Mays L 4
Zea Mays L 4
Paspalum sp 4
Pas pal urn notatum 4
Cynodon dactyl on 4
Axonopus affinis 4
Glycine max L 4
H-19
-------
Table 1 Con't.
26ฐ/22ฐC
Common Name
Scientific Name
# Weeks
44. artichoke, 'green globe1 Cynara scolymus L 4
45. bean, lima, 'Jackson wonder1 Phaseolus lunatus L 3
46. bean, garden . Phaseolus vulgaris L 3
47. bean, pinto Pnaseoliis vulgaris 3
48. bean, 'Tennessee flat' Phaseolus vulgaris L 3
49. bell pepper Capsicum annum L ....5
50. butterpea, 'white Dixie1 Phaseolus lunatus L 3
51. cantelope, 'Hales best jumbo1 Cucumis melo var. reticulatis I 4
52. cantelope, 'honeydew' Cucumis melo var. inodorous L 4
53. chufas Cyperus esculentus L 4
54. clover, 'alyceclover1 Alysicargus vaginal is L 5
55. cotton Gossipium hirsutum L 4
56. cucumber, 'pointsett' Cucumis sativus L 4
57. cowpeas, 'blackeye No. 5' Vigna unguiculata L 3
58. eggplant Solanum melongena L 4
59. millet, 'starr pearl1 Pennisetum glaucum L 4
60. millet, 'brown top1
61. oats, Fl. 501 Avena sativa L 4
62. okra, 'clemson spineless1 Hibiscus esculenta L 4
63. peanuts, 'florunner' Arachis hypogaea L 4
64. peas, 'blackeye' Vigna unguiculata I 3
65. pumpkin, 'king of mammoth1 Cucurbita moschata L 4
66. rice, 'lebonett' Oryza sativa L 4
67. rice, 'brazos' Oryza sativa L ....4
68. rice, 'bluebett1 Oryza sativa L 4
69. rice, 'labelle' Oryza sativa L 4
70. rice, 'star bonnet1 Oryza sativa L 4
71. rubarb, 'Myatt Victoria' Rheum rhaponticum L 4
72. rye, 'wress abruzzi' Secale cerale L 4
73. sorghum, hybrid grain Sorghum bicolor Moench 4
74. squash, 'early summer' Cucurbita maxima L 4
75. squash, 'prolific straight' Cucurbita pepo L 3
76. squash, 'define' zucchini Cucurbita pepo L 3
77. squash, 'acorn' Cucurbita pepo L 3
78. sudangrass, hybrid sorghum SX17 Sorghum sudaness L 4
79. tomato, 'Walter' Lycospersicum esculentum Mill 4
80. watermelon, 'congo' Citrull us vulgaris L 4
81. Douglas-fir Pseudotsuga mensiesii(Mirb.)Franco.6
82. sunflower, 'African1 Hellianthus annuus L 4
11-20
-------
Table 2. Light quality in the "C" chambers
. at the Duke University Phytotron.
3
Photosynthetically Active Radiation0
UV-B 1
seu
0.036
0.007
0.003
0.005
0.540
0.500
1.120
1.010
1.070
0.990
1.460
1.570
1.480
1.590
2.050
2.080
2.160
2.090
!/ uv-Bse
mil CA
Filter2
M
M
M
. M
10+10
10+10
10
10
10
10
3+5
3+5
3+5
5
5
5
5
5
as defined
Cool White
Lights Only
200
240
195
210
235
240
225
235
230
195
180
230
215
170
235
210 '
250
250
in section I.
Cool White
+ FS-40
200 .
245 . .
235
215
240
245
230
240
235
200
185
235
220
175
240
215
255
255
UV-B
weighted by DNA-21.
2/ C.A. = cellulose cecetate filter; M = 5
mil myler type 5.
J3/ Microeinsteins m sec"-'-.
11-21 >
-------
Table 3.
Comparison of the 5 UV-B radiation treatments for height (mm) after 2 weeks as to means,
mean % difference from control for each and average mean percent difference of all
treatments vs. the mylar control.
r
1-0
r-o'
1 2
UV-B Treatments , Means, and % Differences
9.
10.
11.
12.
13.
14.
15.
22.
23.
24.
35.
36.
37.
38.
53.
59.
60.
61.
66.
67.
68.
69.
70.
72.
73.
78.
Species
wheat , ' Wakeland '
wheat, 'CoCorit'
wheat, 'Cajeme'
wheat, 'Crane'
wheat, 'Inia 66R'
wheat, 'Jori'
wheat, 'Super.--X'
barley, 'Belle'
barley, 'Arivat'
barley, 'Hembar'
corn, ' Silverqueen'
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn, 'Coker 71'
chufas
millet, 'Starr Pearl'
millet, 'Brown Top'
oats
rice, 'Lebonett'
rice, 'Brazos'
rice, 'Bluebett'
rice, 'Labelle'
rice, 'Star Bonnet'
rye
sorghum
sudangrass
1
165
129
114
122
152
157
127
184
157
163
142
163
164
150
114
165
78
204
122
132
91
122.33
113
237
193
160
2
146
119
108
112
145
149
124
-
-
-
-
-
-
-
157
-
69
92
102
73
109
94
207
58
119
%
-12
8
- 5
- 8
- 5
- 5
- 2
-
-
-
-
-
-
-
-
- 5
-
-66
-25
-23
-20
-11
-17
-13
-70
-26
3
133
112
104
105
130
162
118
157
131
140
139
136
155
146
96
302
75
219
133
148
101
121
108
211
156
190
%
-19
-13
- 9
-14
-15
3
- 7
-14
-16
. -14
- 1
-17
- 6
- 3
84
83
- 4
7
9
12
11
- 1
- 4
-11
-19
19
4
122
107
103
. 101
124
152
110
133
115
126
110
112
118
90
87
120
60
231
108
121
72
99
84
198
156
152
%
-26
-17
-10
-17
-18
- 3
-13
-28
-27
-23
-23
-31
-28
-40
77
-27
-23
13
-12
- 8
-21
-19
-26
-17
-19
_ c
5
121
110
94
104
127
150
113
141
140
133
125
134
154
130
98
150
71
205
126
144
99 '
123
119
218
141
192
%
-27
-15
-18
-15
-16
- 5
-11
-23
-11
-18
-12
-18
- 6
-14
86
- 9
- 9
1
3
9
9
1
5
- 8
-27
20
ฃ %
-84
-53
-41
-54
-54
:-10
-34
. -66
-54
-55
-36
-66
-40
-56
248
42
-36
-45
-24
-10
-21
-30
-42
-48
135
8
x%
-20.9
-13.2
-10.3
-13.5
-13.5
- 2.4
- 8.5
-21.8
-18.0
-18.4
-12.0
-21.9
-13.3
-18.7
82.5
10.5
-12.0
-11.3
- 5.9
- 2.5
- 5.2
- 7.4
-10.4
-12.0
-33.8
2.0
Means of plant replicates explained in methods section.
"UV-B enhancement levels 1 to 5 defined in Section I.
-------
Table 4. Duncan's Multiple Range Test on Monocots for 2 week height
differences among UV-B irradiation enhancement levels at
the Duke University Phytotron.
Light Level
9.
10.
11.
12.
13.
14.
15.
22.
23.
24.
35.
36.
37.
38.
54.
60.
61.
62.
67.
68.
69.
70.
71.
73.
75.
80.
Species
wheat, 'Wakeland'
wheat, 'CoC or it'
wheat, 'Cajeme1
wheat, 'Crane'
wheat, 'Inia .66R'
wheat, ' Jori'
wheat, 'SuperX'
barley, 'Belle'
barley, 'Arivat'
barley , ' Hembar '
corn, 'Silverqueen'
corn, 'Tobelle'
corn, Hybrid XL
corn, 'Coker 71'
clover
millet, 'Browntop'
oats
okra
rice, 'Brazos'
rice, 'Bluebett'
rice.'Labelle'
rice, 'Star Bonnet'
rhubarb
sorghum
squash, 'Prolific'
watermelon
1
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B
A
B
B,A
B,A
B,A
A
B,A
A
A
B,C
2
B
B
B,A
B
A
A
A
-
-
-
-
-
-
B
-
C
C
C
B
B,A
B,C
B
C
D
3
C,B
C,B
B,A
C,B
B
A
B,A
B
B,C
B
A
B
A
B,A
-- A--5*
A
B,A
B,A
A
A
A
A
B,A
B
B,A
B,A
4
C
C
B,A
C
B
A
B
C
C
C
B
B
B
C
A
B
B
A
B,C
B,C
B
B
C
B
B,A
C
5
C
C,B
B
C,B
B
A
B
C
B,A
C,B
B,A
B
A
B
A
B
B,A
B
B,A
A
A
A
A
B,A
B
A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-23
-------
Table 5. Comparison of the 5 UV-B radiation treatments for height (mm) after 3 weeks as to means,
mean % difference from control for each and average mean percent difference of all
treatments vs. the mylar control.
UV-B Treatments1, Means, and % Differences2
9.
10.
11.
12.
13.
14.
15.
22.
23.
24.
H 35.
10 36.
37.
38.
53.
59.
60.
61.
66.
67.
68.
69.
70.
71.
72.
78.
Species
wheat, 'Wakeland1
wheat, 'Co Cor it1
wheat, 'Cajeme1
wheat, 'Crane1
wheat, 'Inia 66R'
wheat, 'Jori1
wheat, 'Super-X'
barley, 'Belle'
barley, 'Arivat'
barley, 'Hembar1
corn, ' Silverqueen1
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn, 'Coker 71'
chufas
millet, 'Starr Pearl1
millet, 'Brown Top'
oats
rice, 'Lebonett'
rice, 'Brazos'
rice, 'Bluebett'
rice, 'Labelle'
rice, 'Star Bonnet'
rubarb
rye
sudangrass
1
241
210
186
204
226
232
192
282
232
316
327
325
313
295
242
300
182
353
278
276
222
273
233
333
335
304
2
-32
-17
-20
-23
-26
-13
-15
-
-
-
-
_
-
-
311
-
258
237
256
187
241
201
292
193
212
%
202
182
172
169
198
206
188 .
-
-
-
-
_
-
4
-
-27
-15
- 7
-16
-12
-14
-12
-42
-30
3
189
179
168
173
182
261
180
226
207
239
287
269
271
271
226
350
153
340
277
283
218
238
218
300
297
340
%
-22
-15
-10
-15
-20
13
- 6
-20
-11
-24
-12
-17
-13
-'8
- 7
17
-16
- 4
0
3
- 2
-13
- 6
^15
-11
12
4
174
165
203
162
186
212
166.2
207
171
252
229
224
212
166
202
228
123
338
236
246
171
222
183
283
246
284
%
-28
-21
9
-21
-18
- 9
-14
-27
-26
-20
-30
-31
-32
-44
-17
-24
-32
- 4
-15
-11
-23
-19
-22
- 8
-27
- 7
5
165
174
148
158
168
203
163.2
211
192
249
245
250
259
222
204
280
151
329
252
284
206
243
227
306
247
332
%
-16
-13
- 8
-17
-12
-11
- 2
-25
-17
-21
-25
-23
-17
-25
-16
_ ->
-17
- 7
- 9
3
- 7
-11
- 3
-12
-26
9
Z %
-97
-67
-29
-76
-75
-20
-37
-72
-54
-66
-67
-71
-63
-77
-39
-10
-65
-42
-40
-13
-48
-54
-44
-48
-107
-16
x%
-24.3
-16.7
- 7.1
-18.9
-18.8
- 5.0
- 9.2
-23.9
-18.1
-21.9
-22.4
-23.8
-21.0
-25.5
-12.9
- 7.6
-21.8
-10.4
'- 9.9
- 3.2
-11.9
-13.6
-11.1
-11.9
-22.6
- 3.9
1
Means of plant replicates explained in methods section.
"UV-B enhancement levels 1 to 5 defined in Section I.
-------
Table 6. Duncan's Multiple Range Test on Monocots for 3 week height
differences among UV-B irradiation enhancement levels at
the Duke University Phytotron.
Light Level
9.
10.
11.
12.
13.
14.
15.
22.
23.
24.
35.
36.
37.
38.
54.
60.
61.
62.
67.
68.
69.
70.
71.
73.
75.
80.
Species
wheat, ' Wakeland1
wheat, 'CoCorit'
wheat, 'Cajeme'
wheat, 'Crane1
wheat, ' In La .66R'
wheat, 'Jori'
wheat, 'SuperX'
barley, 'Belle'
barley, 'Arivat'
barley, 'Hembar'
corn, 'Silverqueen'
corn, 'Tobelle1
corn, 'Hybrid XL' .
corn, 'Coker 71'
clover
millet, 'Browntop'
oats
okra
rice, 'Brazos'
rice,'Bluebett'
rice,'Labelle'
rice, ' Star Bonnet'
rhubarb
sorghum
squash, 'Prolific'
watermelon
1
A
A
A
A
' A
A
A
A
A
A
A
A
A
A
A
B,A
A
A
A
B,A
A
A
A
A
A
B,C
2
B
B
A
B
B
B
A
-
-
-
_.
-
-
-
-
B,A
-
B
B
B,A
B,A
B
B,A
B
C
D
3
C,B
B
A
B
C
B,A
B,A
B
B,A
B
B,A
B
B
A
A
A
B,A
A
A
A
A
B
B,A
B
B,A
A
4
C,B
B
A
B
C
B
B,C
B
C
B
C
C
C
C
A
B
B
A
B
B
B
B
B
B
B,C
C
5
D
B
A
B
D
B
C
B
B,C
B
B,C
C,B
B
B
A
B
B,A
A
B,A
A
B,A
B
A
B
B,C
B,A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid,
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-25
-------
Table 7. Comparison of the 5 UV-B radiation treatments for final height (mm) of monoco-ts) as to
means, mean % difference from control for each and average mean percent difference of
all treatments vs. the mylar control. .
UV-B Treatments , Mean Weights and % Differences^
9.
10.
11.
12.
13.
14.
15.
22.
23.
24.
35.
36.
37.
38.
53.
59.
60.
61.
66.
67.
68.
69.
70.
71.
72.
73.
Species
wheat 'Wakeland1
wheat, 'CoGorit'
wheat, 'Cajeme'
wheat, 'Crane1
wheat, 'Inia 66R1
wheat, 'Jori'
wheat, 'Super-X
barley, 'Belle'
barley, 'Arivat'
barley, 'Hembar1
corn, ' Silverqucen'
corn, 'Tobelle'
corn, ' Hybrid XL' '
corn, ' Coker 71'
chufas
millet, ' Starr Pearl
millet, 'Brown
oats
rice, 'LebonettV
rice, 'Brazos'
rice, 'Bluebett1
rice, 'Labelle1
rice, 'Star Bonnet1
rhubarb
rye
sudangrass
1
'282
240
229
258
253
251
253
325
286
316
561
518
462
494
392
'409
281
408
378
368
316
362
330
389
457 .
397
2
'234
220
211
219
223
234
246
329
-
350
333
351
265
319
290
341
316
. 463
% '
-17
- 8
- 8
-15
-12
- 7
*-i
'
-20
-
-14
-12
- 5
-16
-12
-12
-12
-31
17
3
226
216
215
224
232
244
241
273
252
239
462
423
394
384
361
385
223
383
397
381
299
346
317
352
431
439
%
-20
-10
- 6 -
-13
- 8
- 3
- 5
-16
-12
-24
-18
-18
-15
-22
-8
-6
-21
-6
5
4
-5
-4
-4
-10
-6
11
fy
219
214
226
216
227
238
215
277
232
252
417
388
327
304
334
319
207
384
340
327
261
316
278
323
351 .
371
%
-22
-11
- 1
-16
-10
- 5
-15
-15
-19
-20
-26
-16
. -29 '.
-38
-15
-22 ,
-26
-6
-10
-11
-17
-13
-19
-17
-23
-7
>
200
208
191
204
201
238
214
270
256
249
439
423
392
378
319
386
248
373
344
363
280
321
3k6
351
345
437
%
r29
-13
-17
-21
-21
- 5
-15
-17
-10
-21
'22
- 8
-15
-23
-19
- 6
-12
- 9
-9
- 1
-11
-11
-4
-10
-25 .
10
ฃ%
~88~
42
32
66
51
20
38
48
41
65
66
42
59
83
-41
-53
-59
-35
-26
-14
-50
-40
-39
-49
' -84
31
27.
-22.1
-10.6
- 8.0
-16.4
-12.7
- 5.0
- 9.5
-16.0
-13.7
-21.7
-22.0
-14.0
-19.7
-27.7
-13.8
-13.3
-19.5
- 8.7
- 6.5
- 3.4
-12.6
-10.1
- 9.8
-12.1
-21.1
7,7
Cleans of plant replicates explained in methods section,
2UV-B enhancement levels 1 to 5 defined in Section I.
-------
Table 8. Duncan's Multiple Range Test on Monocots for 4 week height
differences among UV-B irradiation enhancement levels at
the Duke University Phytotron.
Light Level
Species
9. wheat, ' VJakeland'
10. wheat,'Co Corit'
11. wheat,'Caj erne'
12. x^heat,'Crane'
13. wheat,'Inia .65R'
14. wheat,'Jori'
15. wheat,' SuperX'
22. barley,'Belle'
23. barley,'Arivat'
24. barley,'Hembar'
35. corn,' SLlverqueen'
36. corn, 'Tobelle'
37. corn, 'Ifybrid XL
38. corn,' Qjker 71'
54. clover
60. millet,'Srown top'
61. oats
62. okra
67. rice,' Brazos'
68. rice,'Bluebett'
69. rice.'Labelle'
70. rice,'Star Bonnet'
71. rhubarb
73. sorghum
75. squash,'Prolific'
80. watermelon
1
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B,A
A
A
A
; A
A
A
B,C
2
B
B
B,A
B
B
A
A
-
-
-
-
-
-
'.-
-
A
-
C
C
B,A
A
B
B,A
C,B
B
A
3
B
B
A
B
3, A.
A
A
B
B
B
B
B
B
B
B,A
B,A
B,C
B
A
A
A
B,A
A
B
A
B,A
4
C,B
B
A
B
B
A
B
B
B
B
B
B
C
C
B,A
B
C
B
C
B
A
B
B
C
B
C
5
C
B
B
B
C
A
B
B
B,A
B
B
B
B
B
B
B,A
B,A
B
B,C
B,A
A
B
A
B
B
B,A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.*
UV-B enhancement irradiances are defined in section I.
11-27
-------
Table 9. Comparison of the 5 UV-B radiation treatments for total # of leaves per plant of monocots
as to niaans, mean % difference from control for each and average rac-an percent difference
of all treatments vs. the mylar control.
1 2
UV-B Treatments , Mean Weights and % Differences
9.
10.
.11.
. 12.
13.
14.
15.
22.
23.
24.
35.
M 36.
1 37
N3 J / *
OT 33.
53.
59.
60.
61.
66.
67.
68.
69.
70.
72.
73.
78.
Species
wheat 'Wake land1
wheat, "CoCorit1
wheat, 'Cajeme1
wheat, 'Crane'
wheat, 'Inia- 66R*
wheat, 'Jori'
wheat, 'Super-X1
barley, 'Bella'
barley, 'Arivat1
barley, 'Hembar1
corn, ' Silverqueen1
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn, 'Coker 71'
chufas
millet, Starr Pearl'
millet, 'Brown Top'
oats
rice, ' Labonett'
rice, 'Brazos'
rice, 'Bluebett'
rice, 'Labelle'
rice, 'Star Bonnet'
rye
sorghum
sudangrass
1
29
26
26
27
29
26
23
26
22
27
11
12
12
12
24
28
40
27
24
24
20
21
23
55
27
26
_2
36
27
29
26
29
27
25
30
20
21
24
17
21 .
22
59
23
34
7,
24
4
12
-4
0
4
9
7
-26
-13
0
-15
0
-4
7
-15
31
%_
38
. 31
35
30
30
31
27
25
23
26
11
11
11
11
32
33
47
25
23
25
20
22
22
56
26
30
%
31
19
35
11
3
19
17
- -4
5
-4
0
-8
-8
. -8
33
18
18
-7
. -4
4 .
0
5
-4
2
-4
15
4
30
25
29
25
28
26
23
26
22
26
11
12
11
11
38
31
44
26
22
23
17
23
21
61
25
31
%
3
-4
12
-7
-3
0
0
0
0
-4
0
0
-8
-8
58
11
10
-4
-8
-4
-15
10
-9
11
-7
. 19
c;
* 32
28
23
25
30
30
24
25
23
26
10
12
12
12
33
33
45
26
21
24
20
22
22
54
26
29
%
10
8
8
-7
3
15
4
-4
5
. -4
-9
0
0
0
38
18
13
-4
-13
' 0
0
5
-4
-2
-4
12
1%
69
27
65
.- 7
3
38
30
- 8
10
-12
- 9
- 8
-16
-16
129
54
40
-41
-38
0 '
-30
19
-22
18
-30
77
x%
17.2
6.7
16.3
- 1.9
0.9
9.6
7.6
- 2.7
3.3
- 4.0
- 5.3
- 2.7
- 5.3
- 5.3
43.1
13.4
13.3
-10.2
. - 9.4
0
- 7.5
. 4.8
- 5.4
4.5
- 7.4
19.2
Cleans of plant replicates explained in methods section.
2UV-B enhancement levels 1 to 5 defined in Section I.
-------
Table 10. Duncan's Multiple Range Test on Monocots for Total Number
of Leaves differences among UV-B irradiation enhancement
levels at the Duke University Phytotron.
Light Level
9.
10.
11.
12.
13.
14.
15.
22.
23.
24.
35.
36.
37.
38.
54.
60.
61.
62.
67.
68.
69.
70.
71.
73.
75.
80.
Species
wheat, ' Wakeland1
wheat, 'Co Cbrit'
: wheat, 'Cajeme'
wheat, 'Crane'
wheat, ' Inia 66R'
wheat, ' Jori'
wheat, ' SuperX1
barley, 'Belle'
barley, 'Arivat'
barley, 'Hembar'
corn, ' Silverqueen1
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn, 'Coker 71'
clover
millet , ' Browntop '
oats
okra
rice, 'Brazos'
rice, 'Bluebett'
rice.'Labelle'
rice, 'Star Bonnet'
rhubarb
sorghum
squash, 'prolific'
watermelon
1
C
B
B
B,A
A
B
B
A
A
A
A
A
B,A
A
B
A
A
A
A
A
A
A
A
A
A
C
2
B,A
B,A
B
B
A
B
B,A
-
-
-
-
-
-
-
-
A .
-
B
B
A
A
A
. A
A
A
A
3
A
A
A
A
A
A
A
A
A
A
A
A
B,A
B,C
B,A
A
A
A
B,A
A
A
A
A
A
A
B
4
C
B
B
B
A
B
B
A
: A
A
A
A
B
C
A
A
A
A
B,A
A
A
A
A
A
A
B
5
B,C
B,A
B
B
A
B,A
B
A
A
A
A
A
A
B,A
B,A
A
A
A
B
A
A
.A
A
A
A
B
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-29
-------
fable 11 . Comparison of the 5 UV-B radiation treatments for number of chlorotic leaves as to means, mean
% difference from control for each and average mean percent difference of all treatments vs.
the mylar control.
UV-B Treatments , Means, and % Differences'
M
II
I
O
Species 1
9. wheat, 'Walceland' 8.3
10. wheat, 'CoCorit' 15.3
11. wheat, 'Cajeme' 6.9
12. wheat, 'Crane' 11.9
13. wheat, 'Inia 66R' 9.A
14. wheat, Jori' 13.8
15. wheat. 'Super-X' 10.3
22. barley, 'Belle' 16.2
23. barley, 'Arivat' 14.0
24. barley, 'Hembar' 15.3
35. corn, 'Silverqueen' 4.4
36. corn, ''Tobelle' ' 4.6
37. corn, 'Hybrid XL380' 2.8
38. corn, 'Coker 71' 5.3
53. chufas 7.7
59. millet, 'Starr Pearl* 17.1
60. millet, 'Browntop' 18.8
61. oats 13.3
66. rice, 'Lebonett' 9.2
67. rice, 'Brazos' 4.5
68. rice, 'Bluebett1 5.4
69. rice, 'Labelle' 6.1
70. rice, 'Star Bonnet' 7.3
71. rhubarb . 29.3
72. rye . 10.0
78. sudangrass . 15.4
2
10.6
11.9
12.6
8.3
11.2
12.0
12.0
19.9
18.7
12.5
18.1
7.1
8.7
6.6
8.6
10.2
30.2
16.8
20.0
%
28
-22
83
-30
19
-13
17
158
9
-34
36
-23
93
22
41
40
3
68
30
3
11.3
12.9
11.3
10.5
12.1
15.4
14.3
20.0
17.4
19.8
7.2
8.6
7.3
8.1
16.6
17.2
7.5
18.5
3.0
4.5
5.5
4.7
5.0
24.3
17.4
15.4
%
36
-16
64
-12
29
12
39
24
24
29
64
87
161
53
116
1
-60
39
-67
0
2
-23
-32
-17
74
0
4
12.8
13.2
18.2
13.6
16.7
17.2
16.1
14.7
12.0
13.5
5.3
5.2
4.8
4.7
17.0
17.3
13.4
19.7
7.5
7.5
8.8
15.6
9,1
28.7
19.7
12.8
V
/o
54
-14
.164
14
78
25
26
9
-14
-12
21
13
71
-11
121
1
-29
. 49
-19
67
63
156
25
_2
97
-17
22.8
22.2
20.5
17.9
23.3
23.7
17.3
16.1
12.5
12.3
5.0
4.2
4.4
5.8
15.7
15.7
3.5
4.5
3.0
4.3
3.8
33.3
9.8
29.2
175
45
197
30
148
72
68
1
-11
-20
14
-9
57
9
-8
18
-62
0
-44
-30
-48
14
_2
90
E %
293
507
23
273
95
180
14
. -1
-2
98
91
289
51
395
3
-122
141
-171
160
43
144
-15
-2
237
103
Means of plant replicates explained in methods section.
"UV-B enhancement levels 1 to 5 defined in Sectionl.
-------
Table 12. Duncan's Multiple Range Test on Monocots for Number of Chlor-
otic Leaf differences among UV-B irradiation enhancement
levels at the Duke University Phytotron.
Light Level
9.
10.
11.
12.
13.
14.
15.
22.
23.
24.
35.
36.
37.
38.
54.
60.
61.
62.
67.
68.
69.
70.
71.
73.
75.
80.
Species
wheat , ' Wakeland '
wheat, 'CoCorit'
wheat, 'Cajeme'
wheat, 'Crane'
wheat, 'Inia 66R1
wheat, 'Jori'
Xtfheat, 'S'uperX'
barley, 'Belle'
barley, 'Arivat'
. barley, 'Hembar'
corn, 'Silverqueen'
corn, 'To.belle'
corn, 'Hybrid XL380'
corn,'Coker 71'
clover
millet, 'Browntop'
oats
okra
rice, 'Brazos' nj
rice.'Bluebett^.,^ .
rice,'Labelle'
rice, 'Star Bonnet'
rhubarb
sorghum
squash, 'Prolific'
watermelon
1
B
B
C
B
C
C,B
C
B
B,A
B
B
B
C
B
B
A
A
B
A
B"
~B,A
A
A
A
B,C
C,B
2
B
B
B
B
C
C
B,C
-
-
-
-
- .
-
' -
-
A
-
B,A
BปA
B
B
A
A
A
C
A
3
B
B
C,B
B
C,B
C,B
B,A
A
A
A
A
A
A
A
A
A
A
B,A
B>4,
A
B,A
A
A
A
B,A,C
B
4
B
B
A
B,A
B
B
A
B
B
B
B
B
B
B
A
A
A
B,A
B
B
B,A
A
A
A
B,A
C,B
5
A
A
A
A
A
A
A
B
B
' B
B
B
B
B
A
A
A
. A
B,A
B^A
A
A
A
A
A
C
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-31
-------
Table 13. Comparison of the 5 UV-B radiation treatments for % chlorotic leaves as to means, mean %
difference from control for each and average mean percent difference of all treatments vs.
the mylar control.
UV-B Treatments1, Mean Weights and % Differences2
9.
10.
. 11.
12.
13.
14.
15.
22.
23.
G 24.
w 35'
^ 36.
37.
38.
53.
59.
60.
61.
66.
67.
68.
69.
70.
72.
.. 73.
78,
Species
wheat 'Wakeland1
wheat, 'CoCorit'
wheat, 'Cajeme1
wheat, 'Crane'
wheat, 'Inia 65R!
wheat, 'Jori'
wheat, 'Super-X'
barley, 'Belle1
barley, 'Arivat'
.barley, 'Hembar'
corn, ' Silverqueen'
corn, .'Tobelle'
corvi, HybridXL380
corn, 'Coker 71'
chufas
millet 'StarrPearl1
millet, 'Browntop'
oats
rice, 'Lebonett'
rice, 'Brazos'
rice, 'Bluebett'
rice, 'Labelle1
rice, 'star Bonnet'
rye
sorghum
sudangrass
1
28
60
29
44
34
53
44
63
65
58
41
38
25
43
22
62
47
51
38
20
27
31
35
52
37
60
2
31
44
43
33
38
45
49
53
79
17
19
17
21
19
56
42
87
% '
11
-27
48
-25
12
-15
11
-15
55
-55
- 5
-37
-32
-46
8
14
45
3
30
43
33
36
41
50
54
80
77
77
67
76
65
74
63
57
32
75
31
35
34
38
45
53
66
69
7,
7
28
14
-18
21
-6
23
27
18
33
63
100
150,
72
186
-8
-32
47
-18
75
26
23
29
2
78 -
15
4 .
47
55
64
55
59
66
70
58
54
51
49
43
44
42
43
56
17
72
14
22
31
20.
28
43
62
50
%
68
-8
121
25
74
25
59
-8
-17
-12
20
13
76
-2
.95
-10
-64
41
-63
10
15
-35
-20
-17
69
-17
5
69
78
75
71
76
81
75
64
56
47
48
36
38
. 48
53
51
25
76
37
32
42
107
42
52
74 '
45
7ป
.146
30
159
61
124
53
70
2
-14
-19
17
. -5
52
12
. 141
-18
-47
49
- 3
60
56
245
20
0
100
-25
1%
232
- 33
341
43
229
57
164
21
. .- 13
- 2
100
108
288
81
423
- 50
.-143
192 .
-139
140
59
200
- 17
- 8
259
18
x%
58.0
- 8.3
85.3
10.8
57.4
14.2
40.9
7.0
- 4.3
- 0.7
33.3
36.0
96.0
27.1
140.9
-12.5
-47.5
48.0
-34.9
35.0
14.8
50.0
- 4.3
- 1.9
64.9
. 4.6
Means of plant replicates explained in methods section.
2UV-B enhancement levels 1 to 5 defined in Section I.
-------
Table 14. Duncan's Multiple Range Test on Monocots for %Chlorotic Leaf
differences among UV-B irradiation enhancement levels at
the Duke University Phytotron.
Species
9. wheat,'wakeland'
10. wheat,'CoCorit'
11. wheat,'Caj erne'
12. wheat,'Crane'
13. wheat, ' Inia .66R'
14. wheat,'Jori'
15. wheat,'SuperX'
22. barley,'Belle'
23. barley,'Arivat'
24. barley,'Hembar'
35. corn,'Silverqueen'
36. corn, 'Tdbelle'
37. corn,'Hybrid XL380'
38. corn,'Coker 71'
54. clover
60. millet,'Browntop'
61. oats
62. okra
67. rice,'Brazos'
68. rice,'Bluebett'
69. rice,'Labelle'
70. rice,'Star Bonnet'
71. rhubarb
73. sorghum
75. squash,'prolific'
80. watermelon
Light Level
1
B
B
B
B,C
B
C,B
C
B
B,A
B
B
B
C
B
B
A
A
B
A
A
B,A
A
A
A
B
B,A
2
B
B
B
C
B
C
C
-
-
-
-
-
-
-
-
A
-
A
B,A
A
B
A
A
A
B
A
3
B
B
B
B,C
B
C
B,C
A
A
A
A
A
A
A
A
A
B,A
A
B,A
A
B,A
A
A
A
A
B,A
4
B
B
A
B,A
A
B
B,A
B
B
B
B
B
B
B
A
A
B
A
B
A
B,A
A
A
A
A
B
5
A
A
A
A
A
A .
A
B
B
B
B
B
B
B
A
A
B,A
A
A
A
A
A
A
A
A
B
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-33
-------
Table 15. Comparison of the 5 UV-B radiation treatments for leaf dry weight(g) as to means, mean %
difference from control for each and average mean percent difference of all treatments vs
the mylar control.
1 2
UV-B Treatments , Mean Weights and % Differences
M
M
I
Species "'
1. asparagus
2. carrots
3. celery
4. radish
5. lettuce
6. onion
7. parsnip
8. English peas
9. wheat,'Wakeland' '
10. wheat,'CoCorit'
11. wheat,'Cajerne'
12. wheat,'Crane'
13. wheat,'Inia 66R'
14. wheat,'Jori'
15. wheat,'Super-X1
16. pine, slash
17. pine, loblolly
18. pine, lodgepole
19. pine, ponderosa
20. fir, noble
21. fir, white
22. barley,'Belle'
23. barley,'Arivat'
1
0.07
0.55
0.39
0.25
0.21
0.10
0.45
0.36
0.46
0.47
0.42
0.51
0.53
0.63
0.42
0.84
1.22
0.75
1.17
0.85
0.25
0.69
0.61
2
0.06
0.58
0.65
0.31
0.15
0.10
0.42
0.66
0.50
0.45
0.41
0.42
0.55
0.63
0.46
0.77
1.18
0.78
1.24
0:80
0.54
_
-
.%
-14
5
67
24
-29
0
- 7
83
9
- 4
- 2
-18
4
0
. 10
- 8
- 3
4
6
- 6"
116
-
-
r
0.07
0.71
0.46
0.50
0.17
0.11
0.42
0.49
0.52
0.49
0.48
0.50
0.59
0.74
0.53
0.68
1.05
0.75
0.96
0.82
0.59
0.52
0.45
%
0
29
18
100
-19
10
- 7
36 .
13
4
14
- 2
11
17
26
-19
-14
0
-18
- 4.''
136
-25
-26
4
0.07
0;56
0:35
0.23
0.12
0.08
0.46
0.77
0.44
0.44
0.42
0.41
0.49
0.63
0.46
0.53
0.87
0.54
0.82
0.53
0.44
0.57
0.48
%
0 '
2
-10
- 8
-43
-20
2
114
- 4
- 6
0
-20
- 8 .
0
10
-37
-29
-28
-30
-38
76
-17
-21
5
0:07
0.58
0.41
0.28
0.08
0.09
0.48
0.38
0.43
0.42
0.33
0.35
0.53
0.70
0.39
0.65
1.04
0.68
0.96
0.68
0.36
0.55
0.46
"L
0
5
5
12
-62
-10
7
6
- 7
-11
-21
-31
0
11
- 7
-23
-15
- 9
-18
-20
44
-20
-25
1%
-14
42
79
128
-152
- 20
- 4
239
11
- 17
10
- -71
8
29
38
- 87
-61
-33
-60
-67
372
-62
-42
x%
-3.6
10.5
19.9
32.0
-38;1
- 5.0
- 1.1
59.7
2.7.
-43
2.4
-.17.6
1.9
7.1
9.5
-21.7
-15.2
- 8.3
-15.0
-16.8
93.0
-20.7
-24.0
-------
Table 15 Cont'd
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
V 39.
S 40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
barley, 'Hembar'
broccoli
brussels sprouts
cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabaga
corn, ' Silverqueen'
corn, 'To belle'
corn, Hybrid XL
corn, ' Coker 71 '
grass, 'Perisacola'
grass, 'Arg. Bahia'
grass, 'Bermuda'
grass, carpet
soybean, 'Hardee'
artichoke
bean, lima
bean, garden
bean, pinto
bean,'Tenn. Flat'
bell pepper
butterpea
cantelope, 'Hales'
cantelope, 'Honeydew'
chufas
clover
cotton
cucumber
cowpeas
eggplant
1
0.81
0.54
0.41
0.62
0.35
0.28
0.47
0.48
0.45
0.28
0.43
0.97
1.20
1.18
2.02
0.20
0.16
0.11-
0.11
0.89
0.38
0.96
0.84
0.97
0.88
0.47
0.77
0.74
0.78
0.98
0.14
0.83
1.00
0.71
0.19
2 %
-
-
- -
-
-
-
-
-
-
-
-
" ' -
-
-
-
'
-
- -
- .
- .
-
0.7-2 -14
. - .
. -
0.69 47
. ' -
0.29 -61
0.'26 -6?
-
. ' - - -
0.92 11
0.79 -21
-
- -
3
0.47
0.23
0.22
0.27
0.18
0.11
0.21
0.26
0.23
0.33
0.23
0.92
0.87
1.06
0.89
0.19
0.13
0.06
0.04
0.63
0.41
0.89
0.80
0.87
0.85
0.49
0.70
0.35
0.35
1.40
0.09
0.84
0.81
0.61
0.29
%
-42
-57
-46
-56
-49
-61
-55
-46
-49
18
-47
- 5
-28
-10
-56
.- 5
-19
-45
.-64
-29
8
- 7
- 5
-10
- 3
4
- 9
-53
-55
43
-36
1
-19
-14
53
4
0.56
0.17
0.10
0.23
0.13
. 0.09
0.26
0.21
0.16
0.11
0.18
0.73
0.84
0.77
0.51
0.07
0.08
0.18
0.08
0.58
0.48
0.82
0.58
0.84
0.84
0.50
0.69
0.24
0.31
1.37
0.02
0.91
0.68
0.60
0.27
%
-31
-69
-76
-63
-63
-68
-45
-56
-64
-61
-58
-25
-30
-35
-75
-65
-50
64
-27
-35
26
-15
-31
-13
- 5
6
-10
-68
-60
40
-86
10
-32
-15
42
5
0.54
0.17
0.15
0.20
0.12
0.07
0.15 .
0.18
0.14
0.09
0 . 14
0.70
0.81
0.92
0.77
0.11
0.10
0.14
0.08
0.54
0.33
0.70
0.56
0.90
0.77
0.51
0.64
0.28
. 0.26 '
1.24
0.05
0.81
0.63
0.60
0.21
%
-33
-69
-63
.-68
-66
-75
-68
-63
-69
-68
-67
-28
^33
-22
-62
-45
-38
27
-27
-61
-13
-27
-33
- 7
-13
9
-17
-62
-67
-27
-64
- 2
-37
-15
11
ฃ%
106
-194
-185
-187
-178
-204
-168
-165
-182
-111
-172
-58
-90
-67
-193
-115
-107
-46
-118
-125
21
-49
-83 .
; -31
-20
' 66
-36
-243
-249
109
-186
19
-109
-43
105
x%
-35.4
-64.8
-61.7
-62.3
-59.3
-68.0
-56.0
-55.0
-60.7
-37,0
-57.3
-19.3
-30.0
-22.3
-64.2
-38.3
-35.7
-15.3
-29.0
-41.7
7.0
-16.3
-20,8
-10.3
. - 6.8
16.5
-12.1
-60.8
. -62.2
. 36.4
-61.9
4.8
-27.3
-14.3
35.1
-------
Table 15 Cont'd
M
t-H
I
59. millet,'Starr Pearl'
60. millet,'Browritop'
61. oats
62.. okra
63. peanuts
64. peas, blackeye
65. pumpkin
66. rice,'Lebonett'
67. rice,'Brazos'
68. rice,'Bluebett'
69. rice,'Labelle'
70. rice,'Star Bonnet1
71. rhubarb
72. rye
73. sorghum
74. squash, Early Summer
75. squash,'Prolific'
76. squash,'Zucchini'
77. squash, Acorn
78. sudangrass
79. tomato
80. watermelon
81. Douglas-fir
82. sunflower
1
TTsT
0.75
0.91
0.66
0.95
1.21
1.44
0.65
0.59
0.41
0.50
0.46
0.66
1.31
2.20
1.61
0.85
1.03
0.59
1.55
0.52
0.69
0.33
0.73
_2
2.04
-
0.54
-
1.11
0.56
-
0.56
0.53
0.33
0.50
0.42
-
1.28
0.65
0.95
0.57
-
-
2.51
0.05
0.32
-
-
%
31
. -
-41
-
17
-54
-
-14
-10
-20
0
- 9
-
- 2
-70
-41
-33
- . .
-
62
-90
-54
-
3-
1.40
0.90
1.05
0.54
1.02
0.66
1.46
0.69
0.71
0.37
0.51
0.47
0.35
1.23
1.94
1.02
0.72
0.96
0.59
2.09
0.08
0.45
0.34
0.76
%
-10
20
15
-18
7
-45
1
6
20
-10
2
2
-47
- 6
-12
-37
-15
- 7
0
35
-85
-35
3
4
4 :
1.11
0.66
1.13
0.44
1.02
. 0.47
1.37
0.53
0.53
0.31
0.45
0.38
0.27
1.31
1.90
0.88
0.67
0.83
0.57
1.46
0.07
0.28
0.36
0.76
%
-29
-12
24
-33
7
-61
- 5
-18
-10
-24
-10
-17
-59
0
-14
-45
-21
-20
- 3
- 6
-87
-59
9
4 .
i_
1.52
0.75
1.09
0.41
1.09
0.47
1.30
0.51
0.55
0.36
0.50
0.41
0.17
1.21
1.37
0.70
0.68
0.74
0.42
1.99.
0.05
0.27 .
0.36
0.82
%
-3
0
20
-38
15
-61
-10
-22
- 7
-12
0
-11
-74
- 8
-38
-57
-20
-28
-29
28
-90
-61
- 9
12
E%
~ 11
8
19
- 89
46
-221
- 13
- 48
- 7
- 66
- 8
- 35
-180
- 16
-134
-180
- 89
- 55
- 32
119
-352
-209
- 21
21
x%
- 2.7
2.7
4.7
-29.8
11.6
-55.4
- 4.4
-11.9
- 1.7
-16.5
- 2.0
- 8.7
-60.1
- 4.0
-33.4
-44.9
-22.4
-18.4
-10.7
29.8
-88.0
-52.2
- 7.1
6.8
Cleans of plant replicates explained in methods section.
^UV-B enhancement levels 1 to 5 defined in S.ection I.
-------
Table 16.Duncan's Multiple Range Test for Leaf Dry Weight
differences among UV-B irradiation enhancement
levels at the Duke University Phytotron.
Light Level
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
wheat , *W akeland1
wheat,1 Co Gor it'
wheat , ' Caj erne '
wheat, 'Crane'
wheat,' Inia 66R1
wheat, 'Jori'
wheat, 'SuperX'
pine, slash
pine, loblolly
pine, lodgepole
pine, ponderosa
fir, noble
fir, white
barley, 'Belle'
barley, 'Arivat'
barley , ' Hembar '
broccoli
brussel sprouts
cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabega
corn, 'Silverqueen1
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn, "Coker 71'
grass, 'Pensacola1
grass, 'Arg. Bahia1
grass , ' Bermuda '
grass, carpet
soybean, 'Hardee'
artichoke
1
A
B
B
A
A
A
A
B
A
A
B,A
A
A
A
B
A
A
A
A
A
C
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B,A
2
A
B
A
A
A
A
A
A
A
A
B,A
B,A,C
A
A
B,A
B,A
A
A
A
A
A
-
-
-
-
-
-
-
-
-
-
-
-
.-
.-
-
-
-
-
-
-
. -
-
-
3
A
A
B
A
A
A
A
B
A
A
A
B,A
A
A
A
B,A
B,A
A
B
A
A
B
A
B
B
B
B
B
B
,B
'B
B
A
B
A
B
B,A
B,A
A
A
A
A
A
B,A
4
A
B
B
A
A
A
A
B,A
A
A
B,A
B,C
A
A
B,A
B
B
B
B
C
B,A
B,A
A
B
B
C
B
B
B
B
B
C,B
B
B
A
B
C
B
A
A
A
A
A
A
5
A
B
B
A
A
A
A
B
A
A
B
C
I
A
B
B,A
B,A
A
B
B
B,C
B,A
A
B
B
C
B
B
B
B
B
C
B
B
A
B
B,C
B,A
A
A
A
-
A
B
11-37
-------
Table 16 Con't.
Light Level
Species 1 2 3 4 5
45. bean, lima A - B,A B C
46. bean, garden A B,A ABB
47. bean, pinto A - B B B,A
48. bean,'Tenn. Flat1 A - A A A
49. bell pepper B A B B B
50. butterpea . A - A A A
51. cantelope,1Hales' A B B B B
52. cantelope, 'Honeydew' A B B B B
53. chufas A - A A " A
54. clover A - B,A B B
55. cotton A A A A A
56. cucumber A C,B B C,B C
57. cowpeas A - B C C
58. eggplant A - A A A
59. millet,'Starr Pearl' B,A A B,A B B,A
60. millet,'Brown top' A - A A A
6.1. oats B C A A A
62. okra A - B,A B B
63. peanuts A A A A A
64. peas, blackeye A C,B B C C
65. pumpkin A - A A A
66. rice,'Lebonette' B,A B,A,C A B,C C
67. rice,'Brazos' B,A B A B B
68. rice,'Bluebett' A A A A A
69. rice, 1 abelle' A A A A A
70. rice,'s tar Bonnet' A A A A A
71. rhubarb A - B B B
72. rye A A A A A
73. sorghum A C B,A B,A B
74. squash, early summer A B B C,B C
75. squash,'prolific1 A B B B B
76. squash,'Zjuccini' A - B,A B,C C
77. squash, acorn A - A A A
78. sudangrass B A B,A B B,A
79. tomato A B B B B
80. watermelon A C,B B C C
81. Douglas-fir A - A A A
82. sunflower A ' A A A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations..
UV-B enhancement irradiances are defined, in section I.
11-38
-------
Table 17.
H
Comparison of the 5 UV-B radiation treatments for stem dry weight (g) of dicots as to means,
mean % difference from control for each and average mean percent difference of all treatments
vs. the mylar control,
-I"'' -)
UV-B Treatments., Mean Weights and % Differences"
Species
45. bean, lima
46. bean, garden
47. bean, pinto
48. bean, 'Tenn.Flat.'
49. bell pepper
50. butter pea
51. cantelope, "Hales1
52. cantelope,'^oneydew'
54. clover
55. cotton
56. cucumber
58. eggplant
62. okra
63. peanuts
64. peas
65. pumpkin
71. rhubarb
74. squash Early Sum.
-75-*-squash 'Prolific1
76. squash 'Zucchini'
77. squash, Acorn
79. tomato
80. watermelon
82, sunflower
0.68
0.44
0.59
0.49
0.17
. 0.67
0.43
ป' 0.54
0.04
0.72
0.66
0.19
0.50
0.95
0.64
1.53
0.30
1.69
0.61
0.87
0.33
0.36
0.40
0.71
0.40
0.31
0.09
0.05
0.82
0.25
1.21
0.28
0.51
0.15
0.03
0.11
- 9
82
-79
"91
14
-62
27
-56
-70
~75
-92
-73
0.60
0.40
0.54
0.47
0.17
0.43
0.10
0.10
0.02
0.69
0.27
0.15
0.44
1.05
0.35
1.41
0.13
0.66
0.35
0.42
0.20
0.05
0.15
0.68
-12
_ g
- 8
- 4
0
-36
-77
-81
-50
- 4
-59
-21
-12
11
-45
- 8
-57
-61
43
-52
-39
-86
-63
-4
0.64
0.33
0.51
0.45
0.20
0.42
0.05
0.06
0.01
0.65
0.18
0.11
0.36
1.09
0.40
1.09
0.09
0.39
0,27
0.28
0.17
0.03
0.08
0.63
- 6
-25
-14
- 8
18
-37
-88
-89
-75
-10
-73
-42
-28
15
-38
-29 .
-70
-77
-56
-68
-48
-92
-80
. -11
0.51
0.27
0.50
0.42
0.15
0.40
0.06
0.05
0.01
0,58
0.14
0 . 08
0.30
1.01
0.28
1.06
0.06
0.29
0.22
0.25
0,11
0.02
0.08
0.70
-25
-39
-15
-14
-12
-40
-86
-91
~75
-19
-79
-58
-40
6
-56
-31
-80
-83
-64
-71
-67
-94
-80
. - 1
- 43
~ 82
- 37
- 27
88
-113
~330
~352
~200
".19
"273
~121
~ 80
59
-195
- 67
-207
-291
-238
-191.
-155
"364
-295
- 17
-14.2
-20.5
-12.4
- 8.8
22.1
-37.8
-82.6
-88.0
-66.7
- 4.9
-68.2
-40.4
-26.7
14.7
-48.8
-22.4
.-68.9
-72.5
-59.4
-63.6
-51.5
-91.0.
-73.8
-5,6
Means of plant replicates explained in methods section
"UV-B enhancement levels 1 to 5 defined in Section I,
-------
Table 18.Duncan's Multiple Range Test for Stem Dry Weight
differences among UV-B irradiation enhancement
levels at the .Duke University Phytotron.
Light Level
Species
45. bean, lima A - A A B
46. bean, garden A A B,A B,C C
47. bean, pinto A - B,A B B
48. bean.'Tenn. Flat' A - A A A
49. bell pepper B A B B B
50. butterpea A - B B B
51. cantelope, 'Hales' A B B B B
52. cantelope, 'Honeydew' A B B B B
54. clover A - B,A B B
55. cotton B,A A B,A B,A B
56. cucumber ABB C,B C
58. eggplant A - A A A
62. okra A - B,A B B
63. peanuts B A B,A B,A B,A
64. peas, blackeye A B B B B
65. pumpkin A - A B B
71. rhubarb A - B B B
74. squash, early summer A C,B B C,D D
75. squash,'Prolific' A C B C,B C
76. squash,'Zuccini' A - B C,B C
77. squash, acorn A - B C,B C
79. tomato A B B B B
80. watermelon A C,B B C C
82. sunflower A - A A A
I ~
Light levels not followed by the same letter are significantly o
f)
different (.05 level). Only horizontal comparisons are valid.
V
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-40
-------
Table 19. Comparison of the 5 UV-B radiation treatments for root dry weight(g) as to means, Mean %
difference from control for each and average mean percent difference of all treatments vs.
the mylar control*
1 2
UV-B Treatments , Mean Weights and % Differences . '
i
.e-
Species
1. asparagus
2. carrots
3. celery . .
4. radish
5. lettuce
6. onion
7. parsnip
8. English peas
9. wheat,'Wakeland'
10. wheat,'CoGorit'
11. wheat,'Cajerne'
12. wheat,'Crane'
~13.'"wheat,'Inia 66R'
14. wheat,'Jori1
15. wheat,'Super-X'
16. pine, slash
17. pine, loblolly
18. pine, lodgepole
19. pine; ponderosa
20. fir, noble
21." . fir, white
22. barley,'Belle'
23. barley,'Arivat'.
1
0.03
0.07
0.07
0.23
0.04
0.03
0.09
0.42
0.28
0.45
0.36
0.38
0.43
0.51
0.35
0.15
0.28 .
0.22
0.42
0.20
0.16
0.46
0.65
2
0.02
0.10
0.15
0.24
0.02
0.03
0.08
0.32
0.44
0.47
0.41
0,37
0.55
0.58
0.36
0.15
0.28
0.24
0.38
0.17
0.15
-
7.
-33
43
114
4
-50
0
-11
-24 :
57
4
14
. - 3
28
14
3
0
0
9
-10
-15
-6
.
-
3
0.02
0.11
0.10
0.18
0.02
0.03
0.07
0.30
0.49
0.45
0.55
0.44
0.44
0.67
0.47
0.12 -
0.25
0.22
0.31
0.20
0.27
0.38
.0.46
7o
-33
57
43
-22
-50
0
-22
-29
75
0
53
16
2
31 .
34
-20
-11
0
-26
0
69
-17
-29
; 4
0.02
0.10
0.08
0.13
0.02
0.02
0.09
0.29
0.43
0.44
0.44
0.40
0.42
0.60
0.44
0.12
0.22
0.15
0.27
0.14
.0.12
0.44
0.53
7=
-33
43
14
r43
-50
-33
0
-31
54
- 2
22
5 .
- 2
18
26
-20
-21
-32
-36
-30
-25
- 4
-18
5
0.03
0.09
0.09
0.20
0.03
0.05
0.08
0.31
0.47
0.49
0.38
0.37
0.49
0.65
0.38
0.12
0.23
0.19
0.29 .
0.13
0.07
0.42
0.41
%
0
29
29
-13
-25 %
67
-11
-26
68
9
6
- 3
14
27
9
-20
-18
-14
-31
-35
-56
- 9
-37
T.7,
-100
171
200
- 74
-175
33
- 44
-110
254
11
94
16
42
90
71
-60
-50
-36
-102
- 80
-.18
- 30
- 84
x7o
-25.0
42.9
50.0
-18.5
-43.8
8.3
-11.1
-27.4
63.4
2.8
23.6
3.9
10.5
22.5
17.9
-15.0
-12.5
- 9.1
-25.6
-20.0
-4.5
-10.0
-28.0
-------
Table 19 Cont'd
24.
25.
26.
27..
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48."
49.
50.
51.
52.
53.
54.
55.
56.
57.
barley, 'Hembar'
broccoli
brussels sprouts
cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabega
corn, ' Silverqueen'
corn, 'To .belle'
corn, .Hybrid XL
corn, ' Cbker 71'
grass, 'Pensacola'
grass, 'Arg. Bahia'
grass, 'Bermuda'
grass, carpet
soybean, 'Hardee'
artichoke
bean, lima
bean, garden
bean, pinto
"bean, 'Tenn. Flat'
bell pepper
butterpea
cantelope, 'Hales'
cantelope, ' Ebneydew'
chufas
clover
cotton
cucumber
cowpeas
1 2
0.59
0.13
0.06
0.12
0.05
0.02
0.14
0.09
0.10
0.03
0.07
0.55
1.03 . -
1.05
0.87
0.03
0.04
0.02
0.03
0.30
0.29
0.30
0.34 0.33
0.48
0.37
0.19 0.23
0.28
0.15 0.03
0.21 0.03 .
0.84
0.02
0.21 0.24
0.31 0.11
%
_
-
-
-
_
-
-
-
-
-
-
-
-
-
-
-
-
-
-
'
-
-3
- '
-
21
-
80
86
-
-
14
65
" 3
0.41
0.03
0.02
0.04
0.01
0.01
0.03
0.04
0.03
0.03
0.03
0.59
0.64
1.12
0.83
0.05
0.02
0.01
0.01
0.23
0.41
0.32
0.26
0.44
0.34
0.13
0.20
0.05
0.04
0.99
0.01
0.25
0.16
%
-31
-77
-67
-67
-80
-50
-79
-56
-70
0
-57
9
. -38
7
- 5
67
-50
-50
-67
-23
41 '
7
-24
- 8
" 8
-32
-29
-67
-81
18
-50
19
-48
4
0.47
0.02
0.02
0.05
0.01
0.01
0.02
0.03
0.02
0.01
0.02
0.43
0.50
0.62
0.48
0.01
0.02
0.03
0.02
0.24
0.36
0.27
0.19
0.34
0.31
0.13
0.21
0.03
. 0.03
1.03
0.004
0.20
0.09
%
-20
-85
-67
-58
-80
-50 -
-86
-67
-80
-67
-71
-22
-51
-41
-45
-67
-50
50
-33
-20
24
10
-44
-29
-16
-32
-25
-80
-86
23
-80
- 5
-71
5
0.39
0.02
0.03
0.02
0.01
0.01
0.02
0.03
0.02
0.01
O.OL
0.39
0.53
0.73
. 0.60
0.02
0.03
0.01
0.02
0.20
0.38
. 0.25
0.18 .
0.32
0.27
0.14
0.19
0.04
0.03
0.84
0.01 -
0.17
0.07
<-\ ni.
%
-34
-85
-50
-83
-80
-50
-86
-67
-80
' -67
-86
-29
-49
-30
-31
-33
-25
-50
-33
-33
31
-17
-47
-33
-27
-26
-32
-73
-86
0
-50
-19
-77
r\
E%
- 85
-247
-184
-208
-240
-150
-251
-190
-230
-134
-214
- 44
-138
- 65
- 80
- 33
-125
- 50
-133
- 76
. 96
- 20
-118
- 71
- 51
- 68
- 86
-300
-338
40
-180
10
-261
i <;n
x%
-28.3
-82.3
-01.3
- -69.3
-80.0
-50.0
-83.7
-63.3
-76.7
-44.7
-71.3
-14.5
t46.0
-21.6
-26.8
-11.0
-42.0
-17.0
-44'. 0
-25.3
32.0
- 6.7
-29.4
-23.6
-17.1
-17.1
-28.6
-75.0
-84.5
13.5
-60.0
2.4
-65.3
srv n
58. eggplant
0.04
0,07
75
0.07
-------
Table 19 Cont'd
U)
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
millet, 'Starr Pearl'
millet, ' Brown
oats
okra
peanuts
peas, blackeye
pumpkin
rice, 'Lebonett'
rice, 'Brazos'
rice, 'Bluebett'
rice, 'Labelle'
rice, 'Star Bonnet'
rhubarb
rye
sorghum
squash, Early Summer
squash, ' Prolific '
squash, ' Zucchini'
squash, Acorn
sudangrass
tomato
watermelon
Douglas-fir
sunflower
1
T375T
0.33
0.37
0.19
0.62
0.40
0.26
0.26
0.22
0.17
0.20
0.18
0.12
0.55
1.18
0.32
0.16
0.20
0.14
0.75
0.11
0.06
0.07 .
0.24
2
0.57
-
0.20
- .
0.45
0.15
'
0.19
.0.20
0.10
0.19
0.17
-
0.57
0.31
0.13
0.06
-
. -
1.67
0.01
0.02
-
-
% '
8
-
-46
'
-27
-63
. -
-27
- 9
-41
- 5
- 6
4
-74
-59
-63
-
123
-91
-67
-
-
3
0.55
0.35
0.49
0.11
0.54
0.18
0.34
0.26
0.27
0.14
0.22 .
0.20
0.03
0.50
1.00
0.18
0.10}
0.17
0.11
1.00
0.01
0.03
0.07
0.30
%
4
6
32
-42
-13
-55
31
0
23
18
10
11
-75
.0
-15
-44
-38
-15
-21
33
-91
. -50
0
25
4
0.53
0.21
0.40
0.07
0.52
0.12
0.23
0.19 '
0.19
0,16
0.18
0.13
0.02
0.55
0.95
0.10
0.08
0.13
0.08
0.60
0.01
0.02
0.05
0.31
%
0
-36
8
-63
-16
-70
-12
-27
-14
6
-10
-28
-83
.0
-19
-69
-50
-35
-43
-20
-91
-67
. -29
. -29
5
0.50
0.26
0.81
0.07
0.50
0.14
0.27
0.22
0.22
0.14
0.22
0.16
0 . 04
0.55
0.68
0,0;
0.10
0.16
0.07
1.16
0.01
0.02
0.10
0.29
%
. - 6
-21
119
-63
" 3
-65
4
-15
0
-18
10
-11
-67
0
-42
-72 '
-38
-20
-50
55
-91
-67
43
21
E%
6
- 52
114
-168
- 60
-253
23
- 69
0
- 82
5
- 33
-225
-: 5
-151
-244
-188
- 70
-114
191
-364.
-250
14
75
x%
1.4
- 17 . 2
28.4
-56.1
-14.9
-63.1
7.7
-17.3
0
-20.6
1.3
- 8.3
-75.0
-' 1.4
-37.7
-60.9
-46 -.9
-23.3
38.1
47.7
-90.9
-62.5
4.8
25.0
Means of plant replicates explained in methods section.
o
UV-S enhancement levels 1 to 5 defined in Section I.
-------
Table20.Duncan's Multiple Range Test for. Root Dry Weight
differences among UV-B irradiation enhancement
levels at the Duke University Phytotron.
Light Level
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
wheat , ' Wakeland '
wheat, 'Co Cor it1
wheat , ' Ca j erne '
wheat , ' Crane '
wheat, 'Inia .66R'
wheat, 'Jori'
wheat, 'SuperX'
pine, slash
pine, loblolly
pine, lodgepole
pine, ponderosa
fir, noble
fir, white
barley, 'Belle'
barley, 'Arivat'
barley, 'Hembar'
broccoli
brussel sprouts
cabbage
caulif lower
chard
collards
kale
kohlrabi
mustard
rutabega
corn, !silverqueen'
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn, 'Coker 71'
grass, 'Pensacola'
grass, 'Arg. Bahia'
grass, 'Bermuda'
grass, carpet
soybean, 'Hardee'
artichoke
1
A
A
B
B,A
A
B,A
A
A
A
A
B
A
B
B
C
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B,A
A
A
A
B,A
A
A
A
A
B,A
2
A
A
A
A
A
B,A
A
B
A
A
B
A
A
B,A
C
A
A
A
B,A
B,A
A
-
, -
- '
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
3
A
A
B
B,A
A
B,A
A
B
A
A
A
A
B
A '
A
A
A
A
B,C
A
A
A
B
B
B
B
B
B
B
B
B
'B
A
B
A
B
A
B,A
A
A
A
B
B
B,A
4
A
A
B
B
A
B
A
B
A
A
B
A
B
B,A
B,A
A
A
B
C
B
A
A
B,A
B
B
B
B
B
B
B
B
B
B
B
B,C
B
B
C
B
A
A
B,A
B,A
A
5
A
A
B
B,A
A
A
A
B
A
A
B
A
B,A
A
B,C
A
A
B,A
B,C
B
A
A
B
B
B
B
B
B
B
' B
B
B
B
B
C
B
B
B,C
B,A
A
A :
- '
B ;
B
11-44
-------
Table 20 Con't. _. , T
Light Level
Species 1 2 3 4 5
45. bean, lima B,A - A B,A B
46. bean, garden A A B,A B B
47. bean, pinto A - A B B
48. bean.'Tenn. Flat1 A - B,A B,A B
49. bell pepper B,A ABB B,A
50. butterpea A - B B B
51. cantelope,1Hales' A B B B B
52. cantelope, 'lloneydew1 A B B B B
53. chufas ' .A - A A A
54. clover A - B,A B B
55. cotton B,A A A B,A B
56. cucumber A C,B B C C
57. cowpeas . A - A A A
58. eggplant A - A A A
59. millet,'Starr Pearl1 A A A A A
60. millet,'Browntop1 A - A A A
61. oats B,A B B,A B,A A
62. okra A - B B B
63. peanuts A A A A A
64. peas, blackeye A C,B B C C,B
65. pumpkin B - A B B
66. rice,'Lebonnet A A A A A
67. rice,'Brazos' B,A B,A A B B,A
68. rice,'Bluebett' A A A A A
69. rice,'Labelle' A A A A A
70. rice,'Star Bonnet' A A A A A
71. rhubarb A - B B B
72. rye A A A A A
73. sorghum A C B,A B,A B,C
74. squash, early summer A C,B B C C
75. squash,'Prolific' A B B B B
76. squash,'Zuccini' A - B,A B B,A
77. squash, acorn A - B,A B,C C
78. sudangrass C,B A C,B C B
79. tomato A B B B B
80. watermelon A C,B B C C
81. Douglas-fir A - A A A
82. sunflower A - . A A A
Light levels not followed by the same letter are significantly V
different (.05 level). Only horizontal comparisons are valid.
*
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-45
-------
Table 21. ' Comparison of the 5 UV-B radiation treatments for biomass or total dry weight (g) as to
means, mean % difference from control for each and average mean percent difference of all
treatments vs. the mylar control.
1 ' o '
UV-B Treatments > Mean Weights and % Differences'-
o
Species
1. asparagus
2. carrots
3. celery
4. radish
5. lettuce
6. onion
7. parsnip
8. English peas
9. wheat,'Wakeland'
10. wheat,'CoCorit'
11. wheat,'Cajerne'
12. wheat,'Crane1
"13." wheat,'Inia 66R'
14. wheat",'Jori1
15. wheat,'Super-X'
16. pine, slash
17. pine, loblolly
18. pine, lodgepole
19. pine, ponderosa
20. fir, noble
21. fir, white
22. barley,'Belle'
23. barley,'Arivat'
1
0.09
0.62
0.46
0.48
0.25
0.13
0.53
0.78
0.74
0.92
0.78
0.89
0.95
1.14
0.77
0.99
1.50
0.97
1.59
1.05
0.31
1.15
1.26 :
2
0.08
0.67
0.80
0.56
0.17
0.13
0.49
1.98
0.94
0.92
0.82
0.79
1.10
1.21
0.82
0.92
1.46-
1.01
1.62
0.97
0.69
-
:
%
-11
8
74
17
-32
0
- 8
154
27
0
5
-11
16
6
6
- 7
- 3
4
2
- 8
123
-
-
3
0.09
0.82
0.56
0.68
0.19
0.14
0.49
0.79
1.00
0.94
1.04
. 0.94
1.02
1.41
1.00
0.80
1.30
0.97
1.27
1.02
3.32
0.90
0.91
%
0
32
22
42
-24
8
- 8
1
35
2
33 '
6
7
24
30
-19
-13 .
0
-20
- 3
971
-22
-28
4
0.09
0.65
0.43
0.36
0.14
0.10
0.54
1.06
0.86
0.87
0.86
0.80
0.91
1.23
0.90
0.65
1.09
0.69
1.08
0.67
0.55
1.01
1.01
%
0
5
- 7
-25
44
-23
2
36
16
- 5
10
-10
- 4
8
17
-34
-27
-29
-32
-36
77
n!2
-20
it
,J
0.10
0.67
0.50
0.48
0.12
0 . 14
0.56
0.69
0.90
0.91
0.72
0.72
1.01
1.34
0.77
0.77 .
1.27
0.88
1.25
0.81
0.43
0.97.
0.87
%
11
8
9
0
-52
8
5
-12
22
- 1
- 8
-19
6
18
0
-22
-15
- 9 '
-21
-23
39
- -16
-31
E%
0
..53
98
33
-152
8
- 8
175
100
- 4
41
- 35
25
55
53
- 83
- 59
- 34
72
- 70
1210
- 50
- 79
x%
0
13.3
24.5
8.3
-38.0
- 1.9
- 1.9
44.9
25.0
- 1.1
10.3
- 8.7
6.3
13,8
13.3
-20.7
-14.7
- 8.5
-17.9
-17.4
302.4
-16.5
-26.2
-------
Table 21. Cont'd
M
M
59. millet,'Starr Pearl1
60. millet,'Browntop'
61. oats
62. okra
63. peanuts
64. peas, blackeye
65. pumpkin
66. rice,'Lebonett'
67. rice,'Brazos'
68. rice, 'Bluebett1'
69. rice,'Labelle'
70. rice,'star Bonnet'
71. rhubarb
72. rye
73. sorghum
74. squash, Early Summer
75. squash,'Prolific'
76. squash,'Zucchini'
77. squash, Acorn
78. sudangrass
79. tomato
80. watermelon
81. Douglas-fir
82, sunflower
1
rrnr
1.08
1.28
1.35
2.52
2.25
323
0.91
0.80
0.58
0.70
0.63
1.07
1.86
3.39
3.62
1..62
2.10
1.07
2.30
0.99
1.14
0.40
1.67
2.60
_
0.74
-
2.77
1.00
-
0.74
0.73
0.42
0.69
0.59
-
1.84
0.96
1.59
0.78
-
-
4.19
0.08
0.45
_
-
%
24
-
-42
-
10
-56
-
-19
- 9
-28
- 1
- 6
-
- 1
-72
-56 .
-52
-
-
82
-92
-61 .
-
-
1.95
1.25
1.54
1.09
2.61
1.19
3.20
0.95
0.98
0.51
0.73
0.66
0.51
1.72
2.94
1.86
1.17
1.55
0.90
3.09
0.13
0.62
0.41
1.74
%
16
20
-19
4
-47
- 1
4
23
-12
4
5
-52
- 8
-13
-49
-28
-26
--16
. 34
-87
-46
3
4
1.64
0.87
1.53
0.86
2.64
0.89
2.70
0.72
0.71
0,47
0.64
0.50
0.38
1.86
2.86
1.37
1.01
1.23
0.81
2.06
0.11
. 0.37
0.40
1.70
%
-22
-19
20
-36
5
-60
-16
-21
-11
-19
- 9
-21
-64
0
-16
-62
-38
-41
-24
-10
-89
-68
0
2
2.02"
1.00 .
1.90
0.78
2.70
0.89
2.63
0.73 .
0.77
0.50
0.72
0.57
0.28
1.76
2.04
1.08
1.00 .
1.14
0.60
3.15
0.07
0.36
0.46
1.81
%
- 4
- 7
48
-42
7
-60
-19
-20
- 4
-14
3
-10
-74
- 5
-40
-70
-38
-46
-44
37
-93
-68
15
8
E%
- 9
- 11
46
- 98
25
-224
-36
- 55
- 1
- 72
- 3
- 32
-191
- 14
-140
-237
-156
-113
- 84
143
-361
-242
18
14
f/
X/o
- 2.3
- 3.7
11.5
-32.6
6.3
-55.9
-12.0
-13.7
- 0.3
-18.1
- 0.7
- 7.9
-63.6
- 3.5
-35.1
-59.3
-38.9
-37.8
-28.0
35.8
-90.2
-60.5
5.8
4.8
^Means of plant replicates explained in methods section.
2UV-B enhancement levels 1 to 5 defined in Section I.
-------
Table 21 Con't.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
M 38.
V 39.
ป 40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55;
56.
57.
barley, 'Hembar'
broccoli
brussei sprouts
. cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabega
corn, ' Silverqueen'
corn, 'Tcbelle'
corn, Hybrid XL
corn, ' Coker 71'
grass, 'Pensacola'
grass, 'Arg. Bahia'
grass, 'Bermuda*
grass, e-arpet
soybean j 'Hardee1
artichoke
bean, lima
bean, garden
bean, pinto
bean,'Tenri. Flat'
bell pepper
butterpea
cantelope, 'Hales'
cantelope, '.Honeydew
chuf as
clover
cotton
cucumber
cowpeas
1
1.41
0.67
0.47
0.74
0.40
0.30
0.61
0.57
0.55
0.31
0.50
1.53
2.23
2.22
2.89
0.23
0.20
0.13
0.14
1.19
0.67
1.94
1.62
2.04
1.74
0.83
1.72
1.32
'1.53
1.81
0.20
1.76
1.97
2 %
'
-
_
-
- -
- -
-
_ _
-
-
-
-
-
_ _
_ ' _
-
-
- .
-
-
-
1.45 -10
-
-
1.22 47
:
0.41 -69
0.34 -78
-
-
1.98 13
1.15 042
2_
0.88
0.26
0.24
0.31
0.19
0.12
0.24
0.30
0.26
0.36
0.26
1.51
1.51
2.18
1.72
0.23
0.15
0.07
0.05
0.86
0.82
1.81
1.46
1.85
1.65
0.79
1.33
0.50
0.49
2.38
0.12
1.79
1.24
S\ t~ 4
%
-38
. -61
-49
-58
-53
-60
-61
-47
-53
16
-48
- 1
-32
- 2
-40
0
-25
-46
-65
-28
22
-7
-10
- 9
- 5. -
- 5
-23
-62
-68
31
-40
2
-37
& .
1.03
0.19
0.12
0.27
0.14
0.10
0.28
0.24
0.18
0.11
0.20
1.16
1.34
1.39
0.99
0.08
0.10
0.21
0.10
0.82
0.84
1.73
1.09
1.69
1.60
0.83
1.33
0.32
0.40
2.41
0.03
1.77
0.95
rt
%
-34
-72
-64
-70
-65
-77
-.72
-63
-71
-68
-70
-29
-40
-26
-52
-43
-45
15
-29
-38
6
-25
-38
-15.
-16
- 4
-28
-71
-78
. 15
-70
-11
-57
r* i
Z%
- 99
-204
-187
-192
-183
-203
-187
-168
-191
.-116
-178
- 54
-112
-65
-158
-109
-120
-123
-123
- 97
53
- 43
- 91
- 42
- 29
39
-74
-278
-297
80
. -195
4
-187
p*
x%
-32.9
-68.2
-62.4
-64.0
-60.8
-67.8
-62.3
-56.1
-63.6
-38.7
-59.3
-18.1
-37.4
-21.6
-52.8
-36.2
-40.0
-41.0
-41.0
-32.0
17.7
-14.3
-22.8
-13.9'
- 9.8
9.6
-24.6
-69.5
-74.3
26.5
-65.0
1.0
-46.8
i f
-------
Table 22Duncan's Multiple Range Test for Total Dry Weight
differences among UV-B irradiation enhancement
levels at the fluke University Phytotron.
Light Level
1.
2.
3.
4 .
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
wheat, 'Wakeland'
wheat, 'Cof'orit'
wheat, 'Cajeme'
wheat, 'Crane'
wheat, 'Inia .66R*
wheat, ' Jori1
wheat, 'SuperX'
pine, slash
pine, loblolly
pine, lodgepole
pine, ponderosa
fir, noble
fir, white
barley, 'Belle'
barley, 'Arivat'
barley, 'Hembar'
broccoli
brussel sprouts
cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabega
corn, "Silver queen'
corn, 'To belle'
corn, 'Hybrid XL380'
corn,'Coker 71'
grass, 'Pensacola'
grass, 'Arg. Bahia'
grass, 'Bermuda'
grass, carpet
soybean, 'Hardee'
artichoke
1
A
B
B
A
. A .
A
A
B
B
A
B
A
B,A
B
B
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B,A
2
A
B
A
A
A
A
A
A
. B,A
A
B
B,A
A
B,A
B
B,A
A
. A
A
A
A
-
- ,
-
-
-
-
-
-
-
-.
-
-
-
-
-
-
-
-
-
-
-
-
3
A
A
B
A'
A
A
A
B
A
A
A
A
B,A
A
A
B,A
B,A
A
B
A
A
B
B
B
B
B
B
B
B
B
B
'B
A
B
A
B
A
B,A
A
A
A
A
A
B,A
4
A
B
B
A
A
A
A
B,A
B,A
A
B
B,A
B
B,A
B,A
B
B
B
B
B
A
B,A
B,A
B
B
C
B
B
B
B
B
C,B
B
B
A
B
B
B
A
A
A
A
A
A
5
A
B
B .
A
A
A
A
B
B,A
A
B
B
B,A
B,A
B
B,A
B,A
A
B
B
A
B,A
B
B
B
C,B
B
B
B
B
B
C
B
B
A
B
B
B
A
A
A
- :
A
B
11-49
-------
Table 22 Con't.
Light Level
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
Species
bean, lima
bean, garden
bean, pinto
bean,'Tenn. Flat'
bell pepper
butterpea
cantelope, 'Hales'
cantelope, 'Honsydew'
chufas
clover
cotton
cucumber
cowpeas
eggplant
millet, 'Starr Pearl1
millet, 'Browntop'
oats
okra
peanuts
peas, blackeye
pumpkin
rice, 'L.ebonette'
rice, 'Brazos'
rice,'Bluebett'
rice, 'Labelle'
rice, 'Star Bonnet"
rhubarb
rye
sorghum
squash, early summer
squash, 'Prolific'
squash, 'Zuccini'
squash, acorn
sudangrass
tomato
watermelon
Douglas-fir
sunflower
1
A
A
A
A
B
A
A
A
A
A
B,A
A
A
A
A
A
B,A
A
A
A
A
A
B,A
A
A
A
A
A
A
A
A
A
A
C,B
A
A
A
A
2
.-
A
-
-
A
-
B
B
-
-
A
B
-
-
A
-
B
-
A
B
-
B
B,A
A
A
A
-
A
C
C,B
B
-
-
A
B
C,B
-
-
3
B,A
A
B
B,A
B
B
B
B
A
B,A
B,A
B
A
A
A
A
B,A
B,A
A
B
A
A
A
A
A
A
B
A
B,A
B
B
B
B
B
B
B
. A
A
4
B
B
B
B,A
B
B
B
B
A
B
B,A
C,B
A
A
A
A
B,A
B
A
B
B
B
B
A
A
A
B
A
B.A
C,D
B
C
C,B
C
B
C
A
A
5
C
B
B
B
B
B
B
B
A
B
B
C
A
A
A
A
A
B
A
B
B
B,A
B,A
A
A
A
B
A
B,C
D
B
C
C
B
B
C
A
A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
*
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-50
-------
Table 23. Comparison of the 5 UV-B radiation treatments for biomass partitioning into % leaves as to
means, mean % difference from control for each and average mean percent difference of all
treatments vs. the mylar control.
1 2
UV-B Treatments , Mean Weights and % Differences
M
I
Species
1. asparagus
2. carrots
3. celery
4. radish
5. lettuce
6. onion
7. parsnip
8. English peas
9. wheat,'Wakeland'
10. wheat,'CoCorit1
11. wheat,'Caj erne'
12. wheat,'Crane'
13. wheat,'Inia 66R'
14. wheat,'Jori'
15. wheat,'Super-X1
16. pine, slash
17. pine, loblolly
18. pine, lodgepole
19. pine, ponderosa
20.. fir, noble
21. fir, white
22. barley,'Belle'
23. b.arley,'Arivat'
1
76
88
85
55
84
75
.80
46
41
51
53
57
54
55
54
87
82
77
74
81
80
60
49 .
2
73
86
81
59
87
94
85
65
52
49
49
52
50
52
56
84
81
77
76
83
78
- .
-
%
- 4
- 2
- 5
7
4
- 1
6
41
27
- 4
- 8
- 9
- 7
- 5
4
- 3
- 1
0
3
2
- 3
-
-
3
76
87
80
63
89
77
86
60
51
52
47
52
57
53
53
85
81
77
76
81
71 .
57
49
7,
0
- 1
- 6
15
6
3
8
30
24
2
-11
- 9
6
- 4
- 2
- 2
- 1
0
3
0
-11
- 5
0
4
74
85
83
67
84
80
84
60
50
50
49
51
54
51
51
78
80
79
76
79
79
57
46
%
- 3
- 3
- 2
22
0
7
5
30
22
- 2
- 8
-11
0
- I
- 6
-10
- 1
3
3
- 2
- 1
- 5
- 6
5
72
87
82
60
87
71
85
55
47
47
46
49
51
51
50
86
82
78
77
85
86
56
52
%
:~T
- i
- 4
9
4
- 5
6
20
15
- 8
-13
-14
- 6
- 7
- I
- 1
0
1
4
5
4
- 7
6
ฃ%
- 12
- 8
- 16
53
13
3
25
122
88
12
- 40
- 42
- 7
- 24
- 11
- 17
- 5
4
12
5
- 8
- 17
0
x7ป
- 3.0
- 2.0
- 4.1
13.2
3.3
0.7
6.3
30.4
22.0
- 2.9
- 9.9
-10.5
- 1.9
- 5.9
- 2.8
- 4.3
- 1.2
1.0
3.0
1.2
- 1.9
- 5.6
0
-------
Table 23
Corit'cl
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55;
56.
57.
58.
barley, 'Hembar '
broccoli
brussels sprouts
cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabega
corn, ' Silverqueen'
corn, .'Tobelle'
corn, 'Hybrid XL380'
corn, ' Coker 71'
grass, 'Pensacola'
grass, 'Arg. Bahia*
grass, 'Bermuda1
grass, carpet
soybean, 'Hardee'
artichoke
bean, lima
bean, garden
bean, pinto
bean.'Tenn. Flat1
bell pepper
butterpea
cantelope, -'Hales'
cantelope, ' Koneydew'
chuf as
clover
cotton
cucumber
covTpeas
eggplant
3S
80
88
82
88
93
83
84
82
91
84
63
54
53
70
88
80
85
79
75
57
50
52
48
51
57
45
56
51
56
70
47
51
93
51
50
56
71
76
47
69
- 4
- 2
27
49
0
35
3
33
90
90
88
93
92
87
86
89
91
90
61
58
49
52
83
82
86
80
73
50
49
55
47
51
62
53
70 ,
72
57
75
47
65 .
92
57
%
- 9
13
2
7
6
- 1
5
2
9
0
7
- 3
7
- 8
-26
- 6
9
1
1
- 3
-12
- 2
6
- 2
0
9
18
25
41
2
7
0
27
- 1
12
4
55"
91
88
87
95
94
92
87
89
93
88
63
63.
55
52
. 80
80
86
80
71
57
47
53
50
53
60
52
75
77
55
59
52
72
92
62
%
- 7
14
0
6
8
1
11
4
9
2
5
0
17
4
-26
- 9
0
1
1
- 5
0
- 6
2
4
4
5
16
34
51
- 2
-16
11
41
- 1
22
5
58
89
86
90
90
91
88
87
87
96 .
92
64
60
56
56
81
77
93
80
73
46
48
56
52
53
C4
52
74
76
58 -.
72
52
75
92
62
%
0
11
- 2
10
2
- 2
6
4
5
5
10
2
11
6
-20
- 8
- 4
9
1
- 3
-19
- 4
8
8
4
12
16
32
49
4
29
11
47
- 1
22
ZZ-
-~T6~
38
0
23
16
2
22
10
23
8
21
- 2
35
2
- 71
- 23
' 5
12
4
- 11
- 31
- 12
12
10
8
24
50
118
190
4
36
22
150
- 3
55
x%
- 5.2
12.5
0
7.7
5.3
- 0.7
7.2
3.2
7.7
2.6
7.1
- 0.5-
11.7
0.6
-23.8
- 7.6
1.7
3.9
1.3
- 3.6
-10.3
- 4.0
3.0
3.3
2.7
6.0
16.7
29.5
47.5
1.2
12.0
5.5
37.5
- 1.0
18.3
-------
Table 23 Cont'd
Ul
to
59.
60.
61.
62.
63.
64.
65.
66.
67.
63.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
8.1.
82.
1
millet, 'Starr Pearl '~7F
millet, 'Browntop'
oats
okra
peanuts
peas, blackeye
pumpkin
rice, 'Lebonett'
rice, 'Brazos'
rice, 'Bluebett '
rice, 'Labelle'
rice, 'Star Bonnet'
rhubarb
rye
sorghum
squash, Early Summer
squash, 'Prolific'
squash, ' Zucchini '
squash, Acorn
sudangrass
tomato
watermelon
Douglas-fir
sunflower
73
71
50
38
54
44
72
73
72
71
73
66
71
66
"45
53
50
56
68
52
61
82
44
2
78
-
74
-
40
57
-
75
73
77
73
71
-
70
69
61
73
-
-
60
59
72
-
%
3
.
4
-
5
6
-
4
0
7
3
- 3
-
- 1
5
36
38
-
-12
13
18
'
-
3
^rz
76
69
51
39
55
46
73.
73
71
70
73
68
71
67
57
62
62
66
67
56
69
84
45
%
^T
4
- 3
2
3
2
5
1
0
- 1
- 1
0
3
0
2
27
17
. 24
18
- 1 .
8
13 .
2
2
4
~M
74
74
49
39
53
50
74
73
70
72
77
75
71
69
66
66
68
71
71
. 69 .
76
89
48
%
TT
1
' 4
- 2
3
- 2
14
3
0
- 3
1
5
14
0
5
47
25
36
27
4
33
25
9 .
9
5
76"
78
66
. 52
41
53
48
70
72
73
70
71 -
66 '
70
67
68
68
63
70
65
63.
75~
82
46 -
%
0
7
- 7
4
8
- 2
9
- 3
- 1
1
- 1
- 3
0
- 1
2
51
28
26
25
- 4
21
23
0
5
E%
- 13
12
- 1
4
18
4
27
6
-' 1
4
1
0
17
- 3
1-2
160
108
86
70
- 13
75
'79
11
16
x%
- 3.3
4.1
- 0.4
1.3
4.6
0.9
9.1
1.4
- 0.3
1.0
0.4
0
5.6
- 0.7
3.0
40.0
26.9
28.7
23.2
- 3,3
. 18.8
19.7
3.7
5.3
""Means of plant replicates explained in -.methods section,
UV-B enhancement levels 1 to 5 defined in Section I.
-------
Table24.Duncan's Multiple Range Test for Percent Leaf
differences among UV-B irradiation enhancement
levels at the Duke University Phytotron.
Light Level
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
wheat,1 akeland1
wheat, 'Co Cor it'
wheat , ' Ca j erne '
wheat, 'Crane'
wheat ,'Inia 66R'
wheat, ' Jori'
wheat, 'SuperX'
pine, slash
pine, loblolly
pine, lodgepole
pine, ponderosa
fir, noble
fir, white
barley, 'Belle1
barley , ' Arivat '
barley , ' Hembar '
broccoli
brussel sprouts
cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabega
corn, 'S-.ilverqueen'
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn,' Coker 71'
grass, 'Pensacola'
grass, 'Arg. Bahia1
grass, 'Bermuda'
grass, carpet
soybean, 'Hardee'
artichoke
1
A
B
B
A
A
A
A
B
A
A
A
A
B,A
A
A
A
A
A
B,A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
2
A
B
A
A
A
A
A
A
A
B,A
B,A.
B,A
B
A
A
A
A
A
A
B,A
A
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
3
A
A
B
A
A
A
A
B
A
A
B
B,A
A
A
A
B,A
A
A
B,C
B,A
A
A
A
B
B
B
B
B
B
B
B
B
A
B
A
A
A
A
B,A
A
A
A
A
A
4
A
B
B
A
A
A
A
B,A
A
B,A
B,A
B
B,A
A
A
B
B
B
C
C
A
A
A
B,A
B
C
B
B
B
B,A
B
C,B
B
B
A
A
A
A
B
A
A
A
A
A
5
A
B
B
A
A
A
A
B
A
B
B
B
B,A
A
A
B,A
A
A
B,C
B
A
A
A
B,A
B
C
B
B
B
B
B
C
B
B
A
A
A
A
B,A
A
A
-
A
A
-------
Table 24 Con't. . ,_
Light Level
Species 1234
45. bean, lima A - A A A
46. bean, garden A A A A A
47. bean, pinto C,B - C B A
48. bean,'Tenn. Flat' A - A A A
49. bell pepper B B B,A B,A A
50. butterpea B - A A A
51. cantelope,'Hales1 B A A A A
52. cantelope, 'Honeydew' C B,A B A A
53. ch'ufas A - A A A
54. clover . B - B,A B,A A
55. cotton B B B A B,A
56. cucumber C B,A B A A
57. cox^peas A - A A A
58. eggplant A - A A A
59. millet,'Starr Pearl' A A A A A
60. millet, ' A - A . A A
61. oats . A A A A A
62. okra A - A A A
63. peanuts B A B,A B,A A
64. peas, blackeye B A B,A B B
65. pumpkin A - A A A
66. rice,'Lebonette' A A A A A
67. rice,'Brazos' A A A A A
68. rice/Btuebett' A A A A A
69. rice,'Labelle' A A A A A
70. rice,'Star Bonnet' A A A A A
71. rhubarb A - A A A
72. rye A A A A A
73. sorghum A A A A A
74. squash,, early summer D B,C C B,A A
75. squash, "Prolific' C A B A A
76. squash,'Zuccini1 B - A A A
77. squash, acorn C - B A A
78. sudangrass B,A C B A B
79. tomato B B B A B
80. watermelon B A A A A
81. Douglas-fir B - B A B
82. sunflower A - ' A A A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-55
-------
Table 25. Comparison of the' 5 tlV-B radiation treatments' for biomass partitioning Into "L stems as tb
means, mean % difference from control for each and average mean percent difference of all
treatments vs. the mylar control.
45.
46.
47.
48.
49.
50.
51.
52.
54.
55.
56.
58.
62.
63.
64.
65.
71.
74.
75.
76.
77.
79..
80.
82.
Species 1
bean, lima " 35
bean, garden 27
bean, pinto 29
bean, Tenn.flat 28
bell pepper 20
butter pea 39
cantelope 'Hales' 33
cantelope,'Honeydew1 35
clover 20
cotton 41
cucumber 33
eggplant 36
okra 37
peanuts 30
peas 29
pumpkin 47
rhubarb 25
squash Early Summer 47
squash 'Prolific'
squash ' Zucchini1
squash /';corn
tomato
watermelon
sunflower
37
40
31
36
34
43
UV-B Treatments , Mean Weights and % Differences'
2 %
27 0
25
22
15
41
22
44
29
31
19
36
23
25
-33
-57
0
33
47
0
34
-49
0
-32
3
33
27
29
28
22
32
20
20
17
39
22
29
39
40
30
44
25
33
29
27
22
35
25
38
%_
- 6
0
0
'
10 :
-18
-39
-43
-15
- 5
-33
-19
5
33
3
- 6
0
-30
-22
-33
-29
- 3
-26
-12
A.
37
30
30
28
24
32
16
15
29
37
19
24
43
42
34
41
18
27
26
22
20
24
18
36
%
6
11
3
0
20
-18
-52
-57
45
-10
-42
-33
16
40
17
-13
-28
-43
-30
-45
-35
-33
-47
-16
_5_
35
27
29
29
19
33
16
15
14
37
16
25
40
38
32
42
24
25
21
22
19
27
20
38
%
0
0
0
4
- 5
-15
-52
-57
-30
-10
-52
-31
8
27
10
-11
- 4
-48
-43
-45
-39
-25
-41
-12
zy.
! 0
11
3
: 4
; 50
- 51
-176
: -214
0
- 25
-160
- 83
30
147
31
- 30
- 32
-153
-143
-123
-103
- 61
-147
- 40
x%
0
2.8
1.0
1.3
12.5
-17.0
-44.0
-53.5
.0
- 6.3
-40.0
-27.8
9.9
36.7
7.8
- 9.9
-10.7
-38.3
-35.8
-40.8
-34.4
-15.3
-36.8
-13.2
Means of plant replicates explained in methods section.
n
"nJV-B enhancement levels 1 to 5 defined in section I.
-------
Table26. Duncan's Multiple Range Test for % Stem differences
among UV-B irradiation enhancement levels at the Phytotron-v-
Light Level
Species 1 2 3 4 5
45. bean, lima B,A - B A B,A
46. bean, garden A .A A A A
47. bean, pinto A - A A A
48. bean,'Tenn. Flat' A - A A A
49. bell pepper B,C A B,C B,A C . .
50. butterpea A - B B B
51. cantelope,'Hales' A B B B B
52. cantelope, 'Honeydew' A C,B .B C C '
53. chufas A - B C D
54. clover A - B,A B,A B
55. cotton A A B,A B B,A
56. cucumber A C,B B C,B C
57. cowpeas A - B C D
58. eggplant A - B,A B B,A
59. millet,'Starr Pearl1 A E B C D
60. millet,'Browntop' A - B C D
61. oats A E B C D
62. okra B - B,A A A
63. peanuts B A B,A B,A B
64. peas, blackeye C B,C B,C A B,A
65. pumpkin A - B,A B,A B
66. rice,'Lebonette' A E B C D
67. rice,'Brazos' A E B C D
68. rice.'Bluebett' A E B C D
69. rice,'Labelle' A E B C D
70. rice,'Star Bonnet1 A E B C D
71. rhubarb A - A A A
72. rye A E B C D
73. sorghum A E B C D
.74. squash, early summer A B C,BC,B C
75. squash,'Prolific' A B,C B,A B C
76. squash,'Zuccini' A - B C,B C
77. squash, acorn A - B B B
78. sudangrass A E B C D
79. tomato B,A,C A B,A C B,C
80. watermelon A B B B B
81. Douglas-fir A - B C D
82. sunflower A - . B B B
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-57
-------
Table 27. Comparison of the 5 UV-B radiation treatments for biomass partitionir.^ into % roots as to
means, mean % difference from control for each and average mean percent difference of all
treatments vs. the mylar control.
1 2
. UV-B Treatments , Mean Weights and % Differences
CO
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
wheat, 'Wakeland'
wheat, 'CoCorit'
wheat, ' Cajeme'
wheat, 'Crane'
wheat, 'Inia,66R'
whaat, ' Jori1
wheat, 'Super-X'
pine, slash
i y
pine, loblolly
pine, lodgepole
pine, ponderosa
. fir, noble
fir, white
barley, 'Belle'
barley, ' Arivat'
1
24
12
' 15
45
16
25
20
54
59
49
47
43
46
45
46
13
18
23
26
19
20
40
. 51
2
ป.
TT
14
19
41
13
26
15
35
48
51
51
48
50
48
44
16
19
23
24
17
22
-
%
13
17
27
- 9
-19
4
-25
-35
-19
4
9
12
9
7
- 4
23
6
0
- 8
-11
10
-
"
3
"2T
13
20
37
11
23
14
40
49
48
53
48
43
47
47
15
19
23
24
19
29
43
51
7,
0~
8
33
-18
-31
- 8
-30
-26
-17
- 2
13
12
- 7
4
2
15
- 6
0
- 8
0
45
8
. 0
4
"2T
15
17
33
16
20
16
40
50
50
51
. 49
46
49
49
22
20
21
24
21
21
43
54 .
%
8
25
13
-27
0
-20
-20
-26
-15
2
9
14
0
9
.7
69
11
- 9
.- 8
11
5
8
6
5
"28"
13
13
40
13
29
15
45
53
53
54
51
49
49
' 50
14
18
22
23
15
14
44
48
%
"TT
8
20
-11
-19
16
-25
-17
-10
8
15
19
7
9
9
8
0
- 4
-12
-21
-30
10
- 6
Z%
38
58
93
- 64
- 69
- 8
-100
-104
- 61
12
45
56
9
29
13
115
22
- 13
- 35
- 21
30
25
0
x%.
~974~
14.6
23.3
-16.1
-17.2
- 2.0
-25.0
-25.9
-15.3
3.1
11.2
.14.0
2.2
7.2
3.3
28.8
5.6
- 3.3
- 8.7
- 5.3
7.5
8.3
0
-------
Table 27, Cont'd
1
59. millet,'Starr Pearl' 24
60. millet,'Browntiop' - 27
61. oats 29
62. okra 13
63. peanuts 24
64. peas, blackeye 18
65. pumpkin 9
66. rice,'Lebonett' . 28
67. rice,'Brazos' 27
68. rice,'Bluebett'' 28
69. rice,'Labelle' 29
70. rice,'Star Bonnet' 27
71. rhubarb 9
72. rye 29
73. sorghum . 34
74. squash, Early Summer 9
75. squash,'Prolific' '10
76. squash,'Zucchini' 10
77. squash, Acorn 13
78. sudangrass . . 32
79. tomato 11
SO. watermelon 5
81. Douglas-fir 18
82. sunflower 13
22
26
16
15
25
27
23
27
29
30
31
8
7
- 8
-10
-33
-17
-11
0
-18
. - 7
7
3
- 9
-11
-30
40
5
5
25
55
0
3
28
24
31
10
21
15
10
27
27
29
30
27
7
29
33
9
9
11
12 .
33
9
6
16
16
%
17
-11
7
-23
-13
-17
11
- 4
0
4 .
3
0
-22
0
- 3
0
-10
10
- 8
. 3
-18
20
-11
23
-4
32
26
. 26
7
19
13.
9
26
27
30
28
23
7
29
31
7
8
10
9
29
7
6
11
16
%
33
- 4
-10
. -46
-21
-28
0
- 7
-
7
- 3
-15
-22
0
- 9
-22
-20
0
-31
- 9
-36
. 20
-39
23
5
24
22
34
8
22
15
10
30
28 .
27
30
29
o
39
33
7
10
15
11
35
10
5
18
15
%
0
-19
17
-38
- 8
-17
11
7
4
- 4
3
7
0 .
3
- 3
-22
0
50
-15
9
- 9
0
0
15 .
E%
42
- 33
3
-108
- 75
-.78
22
- 14
4
- 11
- 3
0
- 44
7
- 24
- 56
- 60
60
- 54
. 28
-118
40
- 50
62
x%
10.4
-11.1
0.9
-35.9
-18.8
-19.4
7.4
- 3.6
0.9
- 2.7
- 0.9
0
-14.8
1.7
- 5.9
-13.9
-15.0
20.0
-17.9
7.0
-29.5
10.0
-16.7
20.5
Means of plant replicates explained in methods section.
UV-B.enhancement levels 1 to 5 defined in Section I.'
-------
Table28.Duncan's Multiple Range Test for Percent Root
differences among UV-B irradiation enhancement
levels at the Duke University Phytotron.
Light Level
Species
1. asparagus
2. carrots
3. celery
4. radish
5. lettuce
6. onion
7. parsnip
8. English peas
9. wheat,'Wakeland1
10. wheat,'CoCorit'
11. wheat,'Caj erne'
12. wheat,'Crane1
13. wheat,'Jnia 56R'
14. wheat,'Jori'
15. wheat,'SuperX'
16. pine, slash
17. pine, loblolly
18. pine, lodgepole
19. pine, ponderosa
20. fir, noble
21. fir, white
22. barley,'Belle'
23. barley,'Arivat'
24. barley,'Hembar'
25. broccoli
26. brussel sprouts
27. cabbage
28. cauliflower
29. chard
30. collards
31. kale
32. kohlrabi
33. mustard
34. rutabega
35. corn,;Silverqueen'
36. corn, 'Tobelle'
37. corn,'Hybrid XL3801
38. corn,'Coker 71'
39. grass,'Pensacola'
40. grass,'Arg. Bahia'
41. grass,'Bermuda'
42. grass, carpet
43. soybean,'Hardee1
44. artichoke
1
A A A A A
B,A B,A B A B,A
A B A A A
A A A A A
A A A A A
A A A A A
A A A A A
ABA B,A A
A A A A A
B B,A B B,A A
B B,A A B,A A
B B,A B,A A A
B,A A B B,A B,A
A A A A A
A A A A A
B B B,A A B,A
B B B A B
B B B A B
B,C C B,A A B,A
C C,B C,B A B
A A A A . A
A - A A A
A - A A A
B - A B,A B,A
B - A A A
C - B A A
B - A A A
B - A A A
B - A A A
B - A B,A A
B - . A A A
C - B B,A A
B - B A A
A - A A A
A - A A A .
A - A A A
A - A A A
A - A A A
B - B,A A B,A
A - A A A
A - A A A
A - A A -
A - A A A
A - A A A
11-60
-------
Table 28 Con't.
Light Level
Species 1 2 3 4 5
45. bean, lima A - A A A
46. bean, garden B,A A B B B
47. bean, pinto A - A B B
48. bean,'Tenn. Flat' A - A A A
49. bell pepper A A A A . A
50. butterpea A - A A A
51. cantelope,'Hales' A B B,A B,A B,A
52. cantelope, 'Honeydew1 A B B B B
53. chufas A - A A A
54. clover A - A A A
55. cotton B,A B,A ABB
56. cucumber A C B C C
57. cowpeas A A A A
58. eggplant B - B,A A B,A
59. millet,'S tarr Pearl1 A A A A A
60. millet,'Browntop' A - A A A
61. oats A A A A A
62. okra A - B B B
63. peanuts A B B,A B,A A
64. peas, blackeye A B,A B,A B B
65. pumpkin A - A A A
66. rice,'Lebonette' A A A A A
67. rice,'Brazos' A A A A A
68. rice,' ELuebett' A A A A A
69. rice,L.abelle' A A A A A
70. rice, Star Bonnet' A A A A A
71. rtefesvfb A - A A A
72. rye A A A A A
73. sorghum A A A A A
74. squash,'early summer B B,A A B,A B,A
75. squash,'Prolific' B B,A B B A
76. squash,'Zuccini' C - B B A
77. squash, acorn B,A -ABA
78. sudangrass C,B A B C B
79. tomato B,A B B,A A A
80. watermelon B B,A B,A A B,A
81. Douglas-fir A - . A . B A
82. sunflower B - A A B,A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.*
UV-B enhancement irradiances are defined in section I.
IT-61
-------
. ... .'.... 2
Table 29. Comparison of the 5 UV-B radiation treatments for leaf area (en ) as to means, means %
difference from control for each and average mean percent difference of all treatments
vs. the mylar control.
3 -2
UV-B TreatEsnts , and % Differences
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
wheat , 'Uakeland' "
wheat, 'CoCorit'
wheat, 'Cajame1
wheat, 'Crane'
wheat, 'Inia 66R'
wheat, 'Jori'
wheat, 'Super-X'
pine, slash
pine, loblolly
pine, lodgepole
pine, ponderosa
fir, noble
fir, white
barley, 'Belle'
barley, 'Arivat'
1
9
117
101
77
124
16
117
94
107
98
96
108
118
113
95
56
64
51
61
53
14
156
124
2
9
99
124
91
102
17 .
116
93
107
88
95
81
114
106
105
48
72
53
67
56
30
%
0
-15
23
18
-18
6
-1
-1
0
-10
-1
-25
-3
-6
11
-14
13
4
10
6
114
3
11
127
100
73
97
17
126
83
113
91
112
94
120
141 -
109
43
60
50
48
47
25
125
113
%
22
9
-1
-1
-22
6
8
-12
. 6
-7
17
-13
2
25
15
-23
-6
-2
-21
-11
79
-20
-9
4
8
98
83
67
79
15
114
68
88
78
98
84
112
111
96
38
53
36
.44
34
23
169
126
%
-11
-16
-18
-13
-36
-6
-3
-28
-18
-20
2
-22 '
-5
-2
1
-32
-17
-29
-28
. -36
64
8
, 2
5
11
106
85
HI
86
13 .
133
75
79
72
. 72
71
96 .
106
73
44
58
47
52
42
'21
122
112
ฐ/
A3
22
-9
-16
5
-31
-19
14
-20.
-26
-27
-25
-34
-19
-6
-23
-21
-9
-8
-15
-21
50
-22
-10
ฃ %
33
-31
-12
11
107
-13
18
-61
-38
-64
-7
-94
-25
11
4
-90
-19
-35
-54
-62
307
-34
-17
x,%
8.3
-7.8
-3.0
2.S
26.8
-3.3
4.5
-15.3
-9.5
-16.0
-1.8
-23.5
-6.3
-2.8
1.0
-22.5
-4.8
-8.8
-13.5
-15.5
76.8
-11.3
-5.7
-------
Ta!?Te29. Con't.
29.
30.
31.
24. barley, 'Henbar'
25. broccoli
26. brussel sprouts
27. cabbage
28. cauliflower
chard
collards
kale
32. kohlrabi
33. nustard
34. rutabega
35. corn, 'Silverqueen'
36. corn, 'Tobelle'
37. corn,'Hybrid XL3801
38. corn, 'Coker 71'
39. grass, 'Pensacola1
40. grass, 'Arg. Bahia'
grass, 'Bermuda'
grass, carpet
43. soybean, 'Hardee1
44. artichoke
45. bean, lima
46. bean, garden
47. bean, pinto
48. bean, 'Tenn. Flat1
49. bell pepper
50. butterpea
51. cantelope, 'Hales'
52. cantelope, 'Honeydew'
53. 'chufas
54. clover
cotton
cucumber
cowpeas
41.
42.
55.
56.
57.
53. eggplant
1
161
148
131
189
92
95
120
133
136
123
174
306
401
332
366
30
34
20
23
210
80
367
337
374
381
161
356
269
270
190
49
248
428
465
30
2
.
. .
221
.
246
.
110
S3
287 -
315
%
.
.
'
-34
:
53
-59
-69
16
-26
_3_
96
69
60
75
45
38
64
33 .
72
131
33
245
254
305
285
29
24
11
9
121
96
227
281
297
323
163
171
137
147
214
26
272
331
256
123
ซ/
/a
-40
-53
-54
-60
-51
-60
-47
-38
-47
2
-52
-20
-37
-20
-22
_Q
-29
-45
-61
-42
20
-33
-17
-21
-15
4
-52
-49
-46
13
-47
9
-23
-45.
54
4
141
50
29
66
35
29
53
65
59
33
55
233
262
223
177
11
13
29
13
66
101
172
. 194
275
293
184
133
90
104
232
8
275
225
-144
121
_%_
-12
-66
-78
-65
-62
-69
-56
-51
-57
-74
-63
-24
-35
-42
-52
-63
-62
45
-43
-69
26
. -53
-42
-26
-23 '
14
-63
-67
-61
22
-84
11
-47
-69
51
5
112
. 54
44
63
35
25
. 45
60
44
35
45
216
250
301
267
18
20
11
13
69
85
174
189
326
285
181
130
113
91
206
15
270
236
. 139
39
-30
-64
-66
-67
-62
-74
-63
-55
-68
-73
-74
-29
-38
-21
-27
-40
-41
-45
-43
-67
6
-53
-44
-13
-25
12
-63
-58
-66
8
. -69
9
-45
-70
11
Z %
-82
-183
-198
-192
-175
-203
-166
-144
-172
-145
-194
-73.
-110
-83
-101
-106
-132
-45
-147
-178
52
-144
-137
-60
-63
83
-173
-233
-242
43
-200
45
141
.184
116
x %
-27.3
-61.0
-66.0
-64.0
-58.3
-67.7
-55.3
-43.0
-57.3
-43.3
-64.7
-24.3
-36.7
-27.7
-33.7
-35.3
-44 . 0
-15.0
-49.0
-59.3
17.3
-48.0
-34.3
-20.0
-21.0
20.8
-59.3
-58.3
-60.5
14.3
-66.7
11.3
35.3
61.3
38.7
-------
.CdH't.
59. millet, 'Starr Pearl'
60. millet, 'Browntop'
61. oats
62. okra
63. peanuts
64. peas, blackeye
65. pumpkin
66. rice, 'Lebonett '
67. rice, 'Brazos'
68. rice, 'Bluebett1
69. rice, 'Labelle'
70. rice, 'Star Bonnet1
71. rhubarb
72. rye
73. sorghum
74. squash, Early Summer
M 75. squash, 'Prolific'
76. squash, 'Zucciui'
77. squash, Acorn
78. sudangrass
79. tomato
30. watermelon
81. Douglas-fir
82. sunflower
'r-t
1
313
209
204
224
245
415
519
100
117
77
83
81
201
261
398
485
318
346
245
241
186
202
28
218
2
429
140
.
276
197
107
126
62
100
86
236
164
342
219
524
18
81
or
/.
37
-31
__
13
-53
7
8
-19
20
6
-10
-59
-29
-31
117
-90
-60
3
293
214
214
189
258
244
493
129
137
73
79
81
98
233
323
360
300
344
263
340
39
104
26
229
%
-6
2
5
-16
5
-41
-5
29
17
-5
-:5
0
-51
-11
-19
-26
-6
-1
7
41
-79
-49
-7
5
4
311
189
234
134
285
141
495
98
105
55
92
75
43
293
340
345
294
302
263
335 .
28
63
25
231
-------
Table 30.Duncan's Multiple Range Test for Leaf Area
differences among UV-B irradiation enhancement
levels at the Duke University Phytotron.
Light Level
1.
2,
'3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
xtfheat, 'Wakeland'
wheat, 'CoCorit'
wheat , ' Ca j erne '
wheat , ' Crane '
wheat, 'Inia66R'
wheat, ' Jori1
wheat, 'SuperX'
pine, slash
pine, loblolly
pine, lodgepole
pine, ponderosa
fir, noble
fir, white
barley, 'Belle'
barley, 'Arivat'
barley , ' Hembar '
broccoli
brussel sprouts
cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabega
corn, ' Silverqueen'
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn, 'Co leer 71'
grass, 'Pensacola1
grass , ' Arg . Bahia '
grass, 'Bermuda'
grass, carpet
soybean, 'Hardee1
artichoke
1
A
B,A
B,A
B,A
A
A
A
A
B,A
A
A
A
A
B,A
B,A
A
B,A
A
B,A
B,A
C
B,A
A
A
A
. A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B,A
A
A
A
2
A
B
A
A
B,A
A
A
A
B,A
B,A
A
B
A
B
A
B,A
A
A
A
A
A
-
-
-
-
-
-
- .
-
-
-
-
-
-
-
-
-
-
-
-
-
-
3
A
A
B,A
B,A
B,A
A
A
B,A
A
B,A
A
B,A
A
A
A
B,A
B,C
A
C
B,C
B,A
B
A
C
B
B
B
B
B
B
B
B
A
B
A
B
B
B
A
A
B
B
B
A
4
A
B
B
B
B
A
A
B
B,A
B,A
A
B
A
B
B,A
B
C
B
C
D
B,A
A
A
B,A
B
C
B
B
B
B
B
C,B
B
C,B
A
B
C
C
A
A
A
B,A
C
A
5
A
B
B
.B,A
B
A
A
B,A
B
B
B
B
A
B
B
B,A
B,C
A
B,C
C
B,C
B
A
B,C
B
C
B
B
B
B
B
C
B
C
A
B
B
B
A
A
B
-
C
A
11-Co
-------
Table 30 Con't.
Light Level
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
Species
bean, lima
bean, garden
bean, pinto
bean,'Tenn. Flat1
bell pepper
butterpea
cantelope , ' Hales '
cantelope, 'Honeydew'
chufas
clover
cotton
cucumber
cowpeas
eggplant
millet, ' Starr 'Pearl'
millet , ' Browntop '
oats
okra
peanuts
peas, blackeye
pumpkin
rice, ' Lebonette1
rice, ' Brazos'
rice, 'Bluebett'
rice.'Labelle'
rice, ' Star Bonnet '
rhubarb
rye
sorghum
squash, early summer
squash , ' Prolific '
squash, ' Zuccini'
squash, ' acorn
sudangrass
tomato
watermelon
Douglas-fir
sunflower
1
A
A
A
A
B
A
A
A
A
A
A
A
A
B
A
A
A
A
A
A
A
B,A
B,A
A
B,A
A
A
B,A
A
A
A
A
A
C
A
A
A
A
.2
-
B,C
-
-
A
-
B
C
-
-
A
B
-
-
A
-
B
-
A
C,B
-
B,A
B,A
A
A
A
-
B
C
B
A
-
-
A
B
C,B
-
-
3
B
B,A
B,A
B,A
B
B
B
B
A
B
A
B
B
A
A
A
A
A
A
B
A
A
A
A
B,A
A
B
B
B,A
B
A
A
A
B
B
. B
A
A
4
C
C
B
B
B
B
B
C,B
A
B
A
C
C
A
A
A
A
B
A
C,D
A
B
B
A
B,A
A
C
A
B,A
B
A
A
A
B
B
C
A
A
5
C
C
B,A
B
B
B
B
C,B
A
B
A
C
C
B,A
A
A
A
B
A
D
A
B
B,A
A
B
A
C
B
B
B
A
A
A
B
B
C
A
A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
-------
Table 31, Comparison of the 5 UV-B radiation treatments for leaf density (E/S'I.::-) as to means,
mean ",'<, difference from control for each and average mean percent difference of all
treatments vs. the mylar control
1 2
UV-B Treatments , Mean Weights and % Differences
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
wheat, 'Wakeland1
wheat, 'CoCorit'
wheat , ' Ca j erne '
wheat, 'Crane'
wheat,'Inia 66R'
wheat, 'Jori'
wheat, ' Super-X1
pine, slash
pine, loblolly
pine, lodgepole
pine, ponderosa
fir, noble
fir, white
barley, 'Belle'
barley, ' Arivat'
1
0.77
0.46
0.38
0.33
0.17
0.61
0.37
0.38
0.44
0.49
0.45
0.48
0.44
0.57
0.45
1.50 .
1.93
1.46
1.92
1.62
1.90
0.45
0.50
2-
0.66
0.58
0.52
0.35
0.15
0.59
0.39
1.81
0.47
0.51
0.44
0.53
0.49
0.88
0.44
1.60
1.64
1.46
1.85
1.44
1.88
-
-
%
-14
26
37
6
-12
- 3
5
376
7
4
- 2
10
11
54
- 2
7
-15
0
- 4
-11
- 1
-
-
3
0.64
0.56
0.45
0.65
0.18
0.63
0.33
0.57
0.46
0.56
0.43
0.53
0.50
0.53
0.50
1.60
1.75
1.51
2.08
1.74
2.73
0.42
0.40
%
-17
22
18
97
6
3
-11
50
5
14
- 4
10
14
- 7
11
7
- 9 .
3
8
7
44
- 7
-20
4
0.80
0.57
0.42
0.35
0.15
0.55
0.39
1.01
0.53
0.63
-.44
0.49
0.44
0.60
0.51
1.47
1.66
1.49
1.85
1.58
1.93
0.35
0.39
%
-90
24
11
6
-12
-10
5
166
20
29
- 2
2
0
5
13
- 2
-14
2
- 4
- 2
2
-22
-22
r
6" 67
0.54
0.46
0.36
0.08
0.79
0.36
0.51
0.56
0.59
0.47
0.51
0.56
U.69
0.55
1.49
1-.79
1.45
1.84
1.62
1.63
0.45
0.44
%
-13
17
21
9
-59
30
- 3
34
27
20
4
6
27
21
22
- 1
- 7
- 1
- 4
0
:14
0
12
Z%
-134
89
87
118
- 76
20
- 3
626
59
67
- 4
29
52
74
44
11
- 46
5
- 3
- 6
31
- 29
- 54
x%
-33.4
22.3
21.7
29.5
-19.1
4.9
- 0.7
156.6
14.8
16.8
- 1.1
7.3
13.1
18.4
11.1
2.7
-11.4
1.2
- 0.8
- 1.5
7.8
- 9.6
- 18.0
-------
Table 31 Con'ti
24. barley,'Hembar'
25. broccoli
26. brussels sprouts
27. cabbage
28. cauliflower
29. chard
30. collards
31.' kale
32. kohlrabi
33. mustard
34. rutabega
35. corn, ' Silverqueen.'
36. corn, 'To.belle'
37. corn, Hybrid XL
38. corn,'Coker 71'
39. grass,'Pensac'ola'
40. . grass,'Arg. Bahia'
41. grass,'Bermuda'
42. grass, carpet
43. soybean,'Hardee1
44. artichoke
45. bean, lima
46. bean, garden
47. bean, pinto
48. bean,'Tenn. Flat'
49. bell pepper
50.' butterpea
51. cantelope, 'Hales' ' .
52. cantelope, 'Honeydew1
53. chufas
54. clover
55. cotton
56. cucumber
57. cov;peas
53. eggplant
1
0.51
0.37
0.30
0.33
0.39
0.29
0.41
0.37
0.34
0.22
0.25
0.32
0.30
0.31
0.55
0.62
0.43
0.57
0.45
0.43
0.48
0.27
0.27
0.28
0.25
0.29
0.23
0.28
0.34
0.51
0.28
0.33
0.24
2
-
-
-
-
- .
-
-
-
-
-
-
;
-
-
-
-
-
-
-
-
.-
0.33
-
-
0.28
-
0.26'
0.32
-
. -
0.33 -
0 .25
%
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- .
22
-
-
-3
-
-7
-6
-
-
0
4
3
0.49
0.34
0.36
0.37
0.41
0.30
0.33
0.31
0.32
0.25
0.28
0.37
0.34
0.35
0.31
0.59
0.47
0.54
0.51
0.54
0.44
0.42
0.30
0.30
0.27
0.29
0.43
0.29
0.26
0.63
0.35
0.32
0.25
%
- 4
- 8
20
12
5
3
-2.0
-16
- 6
14
12
16
13
13
-44
- 5
9
- 5
13
26
-13
56
11
7
8
0
87
4
-24
24
25
- 3
4
4
0.40
-.35
0.35
0.34
0.41
0.33
0,83
0.35
0.30
0.50
0.34
0.31
0.32
0.34
0.29
0.63
0.88
0.61
0.56
0.92
0.48
0.48
0.30
0.31
0.30
0..28
0.54
0.28
0.36
0.58
0.34.
0.34
0.3.1
%
-22
- 5
17
3
5
14
102
- 5
-12
127
20
0 3
7
10
-47
2
105
7
24
114
0
78
11
11
20
0 3
135
0
6
14
21 ;.
3
29
5
(X51
0.32
0.33
0.31
0.37
0.32
0.34
0,30
0.31
0.28
0.32
0.32
0.32
0.31
0.29
0.66
-0.48
0.95
0.56
0.92
0.42
0.41
". 0.30
0.28
0.27
0.23
0.63
0.25
0.30
0,58
0.44
. 0.31
0.27
%
0
-14
10
- 6
- 5
10
-17
-19
- 9
27
28
0
7
0
-'47
. 6
12
67
24
114
-13
52
11
o
8
- 3
174
-11
-12
14
57
- 6
13
ฃ%
-25
-27
47
9
5
28
66
-41
-26
168
76
13
27
23
-138
3
126
68
62
253
-25
185
56
18 '
36
- 10 '
396
- 14
- 35
51
104
- 6
50
x%
- 8.5
- 9.0
"15.6
3.0
1.7
9.2
22.0
-13.5.
- 8.8
56.1
25,3
4.2
3.9
7.5
-46.1
1.1
41.9
22.8
20.7
84.5
- 8.3
61.7
13.9
6.0
12.0
- 2.6
131.9
- 3.6
- 8,8
17.0
34.5
- 1.5
12.5
0.23
0.23
0 0.23
0.22 .-4
- 4
- 1.4
-------
Table 31 Cont'd
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76. .
77.
78.
79.
SO.
81.
82.
millet, 'Starr Pearl'
millet, 'Browntop'
oats
okra
peanuts
peas, blackeye
pumpkin
rice, 'Lebonett'
rice, 'Brazos'
rice, 'Bluebett'
rice, 'Labelle'
rice, 'Star Bonnet'
rh ub arb
rye
sorghum
squash, Early Summer
squash, 'Prolific'
squash, 'Zucchini'
squash, Acorn
sudangrass
tomato
watermelon
Douglas-fir
sunflower
1
0.45
0.32
0.45
0.30
0.39
0.30
0.29
0.68
0.51
0.62
0.62
0.60
0.31
0.52
0.55
0.34
0.28
0.31
0.24
0.57
0.27
0.35
1.30
0. 1&
1
0.45
0.32
0.45
0.30
0.39
0.30
0.29
0.68
0.51
0.62
0.62
0.60
0.31
0.52
0.55
0.34
0.28
0.31
0.24
0.57
0.27
0.35
1.30
0.34
2
0.47
-
0.38
-
0.42
0.29
-
0.53
0.42
0.52
0.50
0.48
-
0.54
0.39
0.28
0.26
-
0.48
0.27
0.40
-
- "
%
4
-
-16
. -
8
- 3
-
-22
-18
-16
-19
-20
-
4
-29
-18
- 7
-
-
-16
0
14
f
3
0.46
0.37
0.49
0.29
0.42
0.29
0.30
0.54
0.52
0.59
0.64
0.58
0.48
0.54
0.59
0.44
0.24
0.29
0.22
0.64
0.22
0.49
1.39
0.33
%
~2~~
16
9
- 3
8
- 3
3
f:21
2
- 5
3
- 3
55
4
7
29
-14
- 6
- 8
12
-19
40
7
- 3
4
0734"
0.34
0.51
0.33
0.36
0.35
0.28
0.56
0.54
0.61
0.51
0.52
1.01
0.45
0.54
0.26
0.24
0.27
0.32
0.43
0.24
0.51
1.55
0.32
-------
Table32.Duncan's Multiple Range Test for Leaf
Density differences among UV-B irradiation
I/
enhancement levels at the Duke University Phytotron.'
Species
1. asparagus
2. carrots
3. celery
4. radish
5. lettuce
6. onion
7. parsnip
8. English peas
9. wheat, Vakeland'
10. wheat,'CoC ori t'
11. wheat,'Caj erne'
12. wheat,'Crane1
13. wheat, ' Inia66R'
14. wheat,'Jori'
15. wheat,'SuperX'
16. pine, slash
17. pine, loblolly
18. pine, lodgepole
19. pine, ponderosa
20. fir, noble
21. fir, white
22. barley,'Belle1
23. barley,'Arivat'
24. barley,'Hembar'
25. broccoli
26. brussel sprouts
27. cabbage
28. cauliflower
29. chard
30. collards
31. kale
32. kohlrabi
33. mustard
34. rutabega
35. corn,'Silverqueen'
36. corn, 'Tobelle'
37. corn,'Hybrid XL380'
38. corn,'Coker 71'
39. grass,'Pensacola'
40. grass,'Arg. Bahia"
41. grass,'Bermuda'
42. grass, carpet
43. soybean,'Hardee'
44. artichoke
Light Level
1
A B,A B B,A B
B,A ABA A
A A A A A
B,A B B,A A B,A
A A A A A
B B B B,A A
A A A A A
B B,A B A B,A
B,A B,A B A A
B B,A B,A A A
B B B B A
B A B B,A A
B B,A B B,A A
A A A A A
B,A B B B,A A
A A . A A A
B,A B A A A
B B B A B
B,C C B,A A B,A
C C C,B A B
A B B B B
B - B,A B A
A - A A A
C - A B,C B,A
C - B A B,A
C - B A B
B - A A A
B - A A A
C - B B A
B - B,A A A
B - B,A A A
C - B B A
B - B A A
B - B A A
A - A A A
B - A A A
B - B A B
B - B A B
B - B A B
B - B,A A B,A
A - A A A
B - A B,A
B - B,A B,A A
A A A A
-------
Table 32 Con't.
Light Level
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
Species
bean, lima
bean, garden
bean, pinto
bean,'Tenn. Flat1
bell pepper
butterpea
cantelope , ' Hales '
caataloue, 'Roaeydew'
chufas
clover
cotton
cucumber
cowpeas
eggplant
millet, 'Starr Pearl1
millet, 'Brown top1
oats
okra
peanuts
peas, blackeye
pumpkin
rice, 'L.ebonette'
rice, 'Brazos'
rice, 'Bluebett'
rice, 'Labelle'
rice, 'Star Bonnet'
rwfSiarb ' .
rye
sorghum
squash, early summer
squash, 'Prolific'
squash, 'Zuccini'
squash, acorn
sudangrass
tomato
watermelon
Douglas-fir
sunflower
1
C
A
A
B
A
B
A
B,A
B
A
A
B
B
A
A
A
B,A
A
A
B
A
A
A
A
B
A
B
A
A
A
A
A
A
B,A
A
A
A
A
2
-
A
-
-
A
-
A
B,A
-
-
A
B
-
-
A
-
B
-
A
B
-
B
A
A
C
A
-
A
B
A
B,A
-
-
B,A
A
A
-
-
3
B
A
A
B,A
A
B,A
A
. B
A
A
A
B
B
A
A
'A
A
A
A
B
A
B
A
A
B,A
A
B
A
A
A
B
A
A
A
A
A
' A
A
4
A
A
A
A
A
A
A
A
B,A
A
A
A
A
A
A
A
A
A
A
A
A
B
A
A
C
A
A
A
A
A
B
B,A
A
B
A
A
A
A
5
B
A
A
B,A
A
A
A
B,A
3, A
A
A
B,A
A
A
A
A
A
A
A
A
A
B
A
A
A
A
B
A
B
A
B
B
A
B,A
A
A
A
A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
rr.-7.i
-------
Table 33 . Comparison of the 5 UV-B radiation treatments for root:shoot ratio as to means, mean %
difference from control for each and average mean percent difference of all treatment vs.
mylar control.
1 2
UV-B Treatments and % Differences
Species
1. asparagus
2. carrots
3. celery
4. radish
5. lettuce
6. onion
7. parsnip
8. English peas
9. wheat, 'Wakeland'
10. wheat, 'CoCorit'
11. wheat, 'Cajeme'
12. wheat, 'Crane'
13. wheat, 'Inia 66R1
14. wheat, 'Jori'
15. wheat, 'Super-X'
16. pine, slash
17. pine, loblolly
18. pine, lodgepole
19. pine, ponderosa
fir, noble
fir, white
barley., 'Belle'
20.
21.
22.
23. barley, 'Arivat'
1
.342
.137
.179
.893
.192
.360
.334
1.368
.732
.948
.825
.870
.948
.825
.870
.159
.226
.295
.351
.232
.258
.678
1.059
2
.456
.167
.237
.765
.157
.369
.183
.666
.960
1.034
.940
.809
1.034
.940
.809
.199
.236
.304
.310
.212
.284
V
/o
33
22
32
-14
-18
3
-45
-51
31
9
14
-7
9
14
-7
25
4
3
-12
-9
10
3
.323
.153
.298
.646
.126
.306
.172
.721
.983
.769
.922
.915
.769
.922
.915
.172
.242
.295
.321
.242
.547
.781
1.085
%
-6
12
67
-28
-34
-15
-49
-47
34
-19
12
5
-19
12
5
8
7
0
-9
4
112
15
3
4
.370
.171
.206
.533
.194
.369
.192
.723
1.032
.872
.988
1.021
.872
.988
1.021
.499
.271
.271
.327
..266
.263
.791
1.183
%
8
25
15
-40
1
3
-43
-47
41
-8
20
17
-8
20
17
214
20
-8
-7
15
2
17
12
5
.405
.147
.214
.702
.164
.466
.172
.847
1.170
.980
.967
.046
.980
.967
1.046
.171
.217
.281
.297
.181
.172
.799
.754
18
7
20
-31
-15
29
-49
-38
60
3
17
-95
3
17
20
8
-4
-5
-15
-22
-33
18
-11
-------
Table 33 Con't.
Species
24. barley, 'Ilembar'
25. broccoli
26. brussel sprouts
27. cabbage
28. cauliflower
29. chard
30. collards
31. kale
32. kohlrabi
33. mustard
34. rutabega
35. corn, 'Silberqueen'
36. corn, 'To.belle'
37. corn,'Hybrid XL380'
38. corn, 'Coker 71'
39. grass, 'Pennsacola'
40. grass, 'Arg. Bahia'
41. grass, 'Bermuda'
42. grass, carpet
43. soybean, 'Hardee1
44. artichoke
45. bean, lima
46. bean, garden
47. bean, pinto
48. bean, 'Tenn. Flat'
49. bell pepper
50. butterpea
51. cahtelope, 'Hales1
52. cantelope, 'Honeydew' .160
53. chufas
54. clover
55. cotton
56. cucumber
57. cowpeas
x %
.747
.250
.139
.221
.142
.082
.254
.188
.224
.104
.194
.935
.977
.980
.903
.139
.227
.142
.253
.337
.147
.184
.273
.312
.269
.297
.214
.133
.160
.902
.124
.134
.189
ซ~
~
.311
.218
. __
.093
.082
.136
.099
__
14
-27
-30
-49
2
-48
.911
.113
.107
.136
.074
.089
.163
.167
.128
.103
.112
.946
.961
1.01
.991
.223
.167
.119
.384
.108
.220
.217
.316
.260
.194
.176
.124
.091
.934
.153 .
.166 .
.143
22
-55
-23
-39
-48
9
-36
-11
-43
-2
-42
1
-2
3
10
60
18
-53
14
-27
20
-21
1
-3
-35
-18
_-j
. -43
4
23
24
-24
.896
.101
.143
.198
.057
.069
.089
.147
.129
.079
.171
.949
.944
.974
.994
.336
.222
.204
.263
.448
.143
.186
.218
.255
.243
.189
.193
.096
.090
.877
.135
.125
.093
20
-60
3
-10
-60
-16
-65
-22
-42
-24
-12
2
-3
1
10
142
-2
44
4
33
-3
1
-20
-18
-10
-36
-10
-28 .
-44
-3
9
-7
-51
.754
.130 .
.225
.108
.108
.114
.145
.151
.157
.046
.086
.947
.952
.968
.971
.278
.419
.271
.119
.503
.147
.214
.223
.228
.233
..200
.180
.118
.093
.825
.117
..121
.087
1
-48
62
-51
-24
39
-43
-20
-30
-56
-56
1
-3
-1
8
100
85
91
-53
49
0
16
-18
-27
-13
-33
-16
-11
-42
-9
-6
-10
-54
43
-162
42
-100
-132
32
-144
-53
-115
-82
-110
4
-8
1.2
27
302
82
152
49
96
-29
37
-45
-44
-26
-130
-44
-76
-178
-8
27
9
-177
** /o
14.3
-54.1
13.9
-33.3
-43.9
10. 6
-47.9
-17.6
-38.4
-27.2
-36.6
1.3
-2.5
.4
9.1
100.7
41.2
50.7
24.5
32.0
-9.8
12 3
JU. A- /
-11.3
-14.6
-8.8
-32.6
-14.5
-19.0
-44.4
-3
8 9
v V
2 2
* ฃ-
-44.2
58. eggplant
.148
.157
.169
14
.161
29
9.7
-------
Table 33 Con't.
jpecies
59. millet, 'Starr Pearl'
60. millet, 'Browntop'
61. oats
62. okra
63. peanuts
64. peas, blackeye
65. pumpkin
66. rice, 'Lebonett'
67. rice, 'Brazos'
68. rice, 'Bluebett'
69. rice, 'Labelle'
70. rice, 'Star Bonnet1
71. rhubarb
72. rye
73. sorghum
74. squash, early summer
75. squash, 'Prolific'
76. squash, 'Zuccini'
77. squash, acorn
78. sudangrass
79. tomato
80. watermelon
81. Douglas-fir
82. sunflower
1
.325
.436
.410
.154
.348
.216
.096
.398
.366
.408
.418
.393
.099
.417
.520
.094
.112
.108
..153
.468
.129
.053
.216
.151
2
.278
.367
.192
.173
.332
.369
.296
.373
.407
.440
.471
.082
.078
.674
.056
.052
%
-15
-11
-45
-20
-17
1
-28
-11
4
6
-9
-13
-30
44
-57
-2
.
3
.389
.332
.465
.113
.267
.180
.117
.379
.380
.426
.430
.389
.073
.403
.505
.105
.099
.124
.139
.485
.107
.065
.202
.195
%
20
-24
13
-27
-23
-17
22
-5
4
4
3
-1
-26
-3
-3
12
-12
15
-9
4
-17
23
-7
29
4
.563
.434
.350
.079
.242
.153
.098
.346
.367
.537
.389-
.314
.075
.416
.467
.076
.088
.116
.098
.419
.076
.062
.127
.200
%
73
-1
-15
-49
-31
-29
1
-13
0
44
_7
-20
-24
0
-10
-19
-21
7
-36
-11
-41
17
-41
33
5
.329
.291
.724
.090
.287
.187
.119
.451
.395
.376
.433
.414
.164
.443
.508
.080
.118
.180
.126
.564
.124
.054
.240
.182
%
1
-33
77
-42
-18
-13
24
13
8
-8
4
5
66
6
-2
-15
5
67
-18
21
-4
2
11
21
E %
80
58
65
-117
-116
179
48
-21
13
13
-11
-12
15
8
-25
-35
-58
89
-63
58
-119
40
37
82
x %
19.9
-19.2
16.2
-39.0
-29.0
-19.8
16.0
-5.3
3.2
3.2
-2.8
-3.1
5.1
2.0
-6.2
-8.8
-14.5
29.6
-20.9
14.4
-29.7
9.9
-12.2
27.4
Means of plant replicates explained in methods section.
"UV-B enhancement levels 1 to 5 defined in Section I,
-------
Table 34Duncan's Multiple Range Test for Root:Shoot Ratio
differences among UV-B irradiation enhancement
levels at the Duke University Phytotron.
Light Level
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
Species
asparagus
carrots
celery
radish
lettuce
onion
parsnip
English peas
wheat, 'Wakeland1
wheat, 'CoCorit'
wheat, 'Cajerae'
wheat, 'Crane1
wheat, 'Inia 66R'
wheat, ' Jori'
wheat, ' SuperX'
pine, slash
pine, loblolly
pine, lodgepole
pine, ponderosa
fir, noble
fir, white
barley, 'Belle'
barley, 'Arivat'
barley ,' Hembar '
broccoli
brussel sprouts
cabbage
cauliflower
chard
collards
kale
kohlrabi
mustard
rutabaga
corn, 'Silverqueen'
corn, 'Tobelle'
corn, 'Hybrid XL380'
corn,'Coker 71'
grass, 'Pensacola'
grass, 'Arg. Bahia'
grass, 'Bermuda'
grass, carpet
soybean, -'Hardee'
artichoke
1
A
B,A
A
A
A
A
A
A
A
B
B
B
B,A
A
A
B
B
B
B,C
C
A
A
A
B
B
C
B
B
B
B
B
C
B
B
A
A
A
B
B
A
A
A
A
A
2
A
B,A
B
A
A
A
A
B
A
B,A
B,A
B,A
A
A
A
B
B
B
C
C,B
A
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
3
A
B
' A
A
A
A
A
B,A
A
B
A
B,A
B
A
A
B,A
B
B
B,A
C,B
A
A
A
A
A
B
A
A
A
A
A
'B
B
A
A
A
A
A
B,A
A
A
A
A
A
4
A
A
A
A
A
A
A
B,A
A
B,A
B,A
A
B,A
A
A
A
A
A
A
A
A
A
A
B,A
A
A
A
A
A
B,A
A
B,A
A
A
A
A
A
A
A
A
A
A
A
A
5
A
B,A
A
A
A
A
A
A
A
A
A
A
B,A
A
A
B,A
B
B
B,A
B
A
A
A
B,A
A
A
A
A
A
A
A
A
A
A
A
A
A
B,A
B,A
A
A
-
A
A
11-75
-------
Table 34 Con't.
Light Level
45.
46.
47.
48.
49.
50.
51.
52.
53.
.54,
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
Species
bean, lima
bean, garden
bean, pinto
bean,'Tenn. Flat''
bell pepper
butterpea
cantelope , ' Hales '
cantelope, .'Honeydew'
chufas
clover
cotton
cucumber
cowpeas
eggplant
millet, 'Starr Pearl'
millet, 'Browntop'
oats
okra
peanuts
peas, blackeye
pumpkin
rice, 'L.ebonette'
rice, 'Brazos'
rice,'Bluebett'
rice, 'Labelle'
rice, 'S tar Bonnet'
rhubarb
rye
sorghum
squash, early summer
squash, 'Prolific'
squash, 'Zuccini'
squash, acorn
sudangrass
tomato
watermelon
Douglas-fir
sunflower
1
A
A
A
A
A
A
A
A
A
A
B
A
A
B
B
A
A
A
A
A
A
B,A
A
A
A
A
A
A
A
B
B
B
B,A
C,B
B,A
B
B,A
B
2
-
A
-
-
A
-
A
B
-
-
B
C
-
-
B
-
A
B
B
-
B
A
A
A
A
-
A
A
B,A
B,A
-
-
A
B
B,A
-
-
3
A
A
A
A
A
A
A
B
A
A
A
B
A
B,A
B,A
A
A
B
B,A
B
A
B,A
A
A
A
A
A
A
A
A
B
B
A
C,B
B,A
B,A
B,A
A
4
A
A
B
A
A
A
A
B
A
A''
B
C
A
A
A
A
A
B
B,A
C
.A
B
A
A
A
A
A
A
A
B,A
B
B
B
C
B,A
A
B
A
. 5
A
A
B
A
A
A
A
B
A
A
B
C
A
B,A
. B
A
A
B
B,A
B
A
A
A
A
A
A
A
A
A
B,A
A
A
A
B
A
B,A
A
B,A
Light levels not followed by the same letter are significantly
different (.05 level). Only horizontal comparisons are valid.
See species list for scientific names and varietal designations.
UV-B enhancement irradiances are defined in section I.
11-76
-------
Table. 35 Susceptibility ratings for 82 agricultural crops grown under 4
or 5 different UV-B enhancement regimes in the Duke University
Phytotron. Favored (+) = biomass increases of 5% or more, re-
sistant (0) = biomass ฑ 5% of the mylar control, moderately
. susceptible (1) = 5-25% reduction in biomass, susceptible (2) =
25-50% reduction in biomass, highly susceptible (3) = greater
than 50% reduction in biomass belox* mylar control.
I. ChenopodiacePe?
1 chard
II. Compositae
1. artichoke
2. lettuce
3. sunflower
III. Cruciferae
1. broccoli
2. brussel sprouts
3. cabbage
4. cauliflower
5. collards
6. kale
7. kohlrabi
8. mustard
9. radish
10. rutabega
IV. Cucurbitaceae
1. cantelope, 'Hales' ,
best jumbo '
2. cantelope, 'timeydew'
3. cucumber
4. squash, acorn
5. squash, early summer
Rating V. Grainineae
3
3
3
3
3
3
3
2
2
3
2
3
6. squash,'Prolific Straight' 2
7. squash,'Zuccini' 2
8. pumpkin 1
9. watermelon 3
VI.
Rating
1. barley,'Arivat' 1
2. barley,'Belle' . 1
3. barley,'Henbar' 2
4. chufas +
5. corn,'Silverqueen' 2
6. corn,'Sweet Tobelle' 2
7. corn,'Hybrid XL380' 2
8. corn,'Coker 71' 3
9. grass,1 Pensacola1 2
10. grass,'Arg. Bahia' 2
11. grass,' Bermuda' 1
12. grass, carpet 2
.13. millet,'Starr Pearl1 1
14. millet,'Browntop' 1
15. oats +
16. rice,'Lebonnet' 1
17. rice,'Brazos' 0
18. rice,'Bluebett' 1
19. rice.'Labelle' 0
20. rice,'Star Bonnet' 1
21. rye 1
22. sorghum 1
"23. sundangrass +
24. wheat,*Cajerne' +
25. wheat,1CoCorit1 0
26. wheat,'Crane' 1
27. wheat,' Iriia 66R* 0
28. wheat,'Jori' +
29. wheat,'Super Xf +
30. wheat,'Wakeland' +
Leguminosae
1. bean, garden 1
o
r:-/?
-------
Table 35 Con't.
VI. Leguminosae Rating
2. bean, lima 1
3. bean, pinto 1
4. bean,'Tenn. Flat' 1
5. butterpea 1
6. cowpaa 1
7. clover 3
8. peanuts +
9.. peas, blackeye 3
10. peas, English +
11. soybean 2
VII. Liliaceae
1. asparagus 0
2. onion 0
VIII. Malvaceae
1. cotton 0
2. okra 2
"IX. Pinaceae
1. pine, loblolly 1
2. pine, lodgepole 1
3. pine, ponderosa 1
4. pine, slash 1
5. Douglas-fir 0
6. fir, noble 1
7. fir, white +
X. Polygonaceae
1. rhubarb 3
XI. Solanaceae
1. bell pepper 0
2. eggplant +
3. tomato 3
XII. Umbelliferae
1. carrots +
2. celery +
3. parsnip 0
-------
Table 36 . List of species by sensitivity rating, family, overall
increase ( + ), decrease (-), or no change (0) in leaf density.
(+) Favored Species
_ .
+ 1. artichoke - Compositae
+ 2. sunflower - Compositae
+ 3. radish - Cruciferae
+ 4. chufas - Gramineae
+ 5. oats - Gramineae
- 6. sudangrass - Gramineae
0 7. wheat, 'Cajeme' - Gramineae
t 8. wheat, Mori' - Gramineae
+ 9. wheat, "Super X'- G.ranineae
+ 10. ehrsy,' Wakelanc? - Gramineae
+ 11. peanuts - Leguminosae
+ 12. English peas - Leguminosae
+ 13. fir, white - Pinaceae
0 m. eggplant - Solanaceae
+ 15. carrots - Umbelliferae
+ 16. celery - Umbelliferae
(0) Resistant Species
~D
0 1. rice, 'Brazos '- Gramineae
- 2. rice, 'Labelle '- Gramineae
+ 3. wheat,'CoCorit'- Gramineae
+ 4. wheat,'inia 66R'- Gramineae
- . 5.. asparagus - Liliaceae
0.6. onion - Liliaceae
0 7. cotton - Malvaceae
+ 8. Douglas-fir - Pinaceae
0 9. bell pepoer - Solanaceae
0 10. uarsniD - Unbelliferae
(1) Moderately Susceptible Species
D_
+ 1. lettuce - Compositae
2. pumpkin - Cruciferae
3. barley, 'Arivat'- Gramineae
- 4. barley,'Belle'- Gramineae
+ 5. grass,'Bermuda'- Gramineae
6. millet,'Star Pearl'- Gramineae
+ 7. millet, 'Browntop' - Gramineae
- 8. rice,'Lebonnet'- Gramineae
9. rice,'Bluebett- Gramineae
- 10. rice,'Star Bonnet'- Gramineae
+ 11. rye, - Gramineae
- 12. sorghum - Gramineae
+ 13. wheat,'Crane'- Gramineae
f 14. bean, garden - Leguminosae
+ 15. bean, lima - Leguminosae
+ 16. bean, pinto - Leguminosae
(1) Moderately Sensitive Species
Ei
+ 17. bean,*Tenn. Flat'- Leguminosae
+ 18. butterpea - Leguminosae
+ 19. cowpea - Leguminosae
- 20. pine, loblolly - Pinaceae
0.21. pine, lodgepole - Pinaceae
0 22. pine, ponderose - Pinaceae
0 23. pine, slash - Pinaceae
0 24. fir, noble - Pinaceae
(2) Sensitive Species
+ 1. mustard - Cruciferae
- 2. cantelope,'Hales best jumbo'-
Cucurbitaceae
3. Cantelope,'li'oneydew' - Cucurbitaceae
- 4. squash, acorn - Cucurbitaceae
- 5. squash,'Prolific Straight1 -
Cucurbitaceae
6. squash, 'Zuccini' - Cucurbitaceae
7. barley,'Hemb r'- Gramineae
+ 8. corn,'S ilverqueen'- Gramineae
+ 9. corn,'S/?eet Tobelle' - Gramineae
+ 10. corn,'Hybrid XL380' - Gramineae
0 11. grass,1 Pensacola' - Gramineae
+ 12. grass, 'Arg. Bahia' - Gramineae
+.13. grass, carpet - Gramineae
+ 14. soybean - Leguminosae
0 15.' okra Malvaceae
(3) Highly Sensitive Species
+ 1. chard - Chenopodiaceae
2. broccoli - Cruciferae
+ 3. brussel sprouts - Cruciferae
+ 4. cabbage - Cruciferae
+' 5. cauliflower - Cruciferae
6. collards - Cruciferae
7. kale - Cruciferae
8. kohlrabi - Cruciferae
+ 9. rutabega-- Cruciferae
+ 10. cucumber - Cucurbitaceae
- 11. squash, early summer - Cucurbitaceae
+ 12. watermelon - CucurbiLaceae ''~*
- 13. corn, 'Coker 7i - Gramineae
+ 14. clover - Leguminosae
+ 15. peas, blackeye - Leguminosae
+ 16. 'rhubarb- Polygonaceae
- 17. tomato - Solanaceae
IT-7 9
-------
EFFECTS OF ULTRAVIOLET-B RADIATION ENHANCEMENTS
ON SOYBEAN AND WATERMELON VARIETIES
Abstract
Nineteen different soybean (Glycine max L. Merr.) and 3 different
watermelon (Citrullus vulgaris L.) varieties were grown in controlled
environmental chambers at the Duke University Phytotron under 5 different
UV-B enhancement regimes. Height was measured weekly. After 4 weeks the
plants were harvested and analysed for 1) leaf fresh and 2) dry weight,
3) stem fresh and 4) dry weight, 5) root fresh and 6) dry weight,
7) total fresh and 8) dry weight biomass, 9) leaf area, 10) % leaves,
11) % stems, 12) % roots, 13) rootrshoot ratio, 14) chlorosis, and
15) leaf density.
Significant differences among varieties for sensitivity to UV-B
radiation was found. Biomass, as determined by fresh and dry weights, and
height were reduced. The % biomass partitioned into leaves increased, that
into stem decreased and for the majority of the varieties the % in roots
decreased. Rootrshoot ratios varied, depending primarily on the relative
changes in root biomass. Leaf density was consistently increased, being
more pronounced in watermelons. Significant differences in the amount of
chlorotic leaf surface were also observed.
III-l
-------
.Introduction
'Hardee' soybean in the screening study of section 2 was a sensitive
species showing pronounced interveinal chlorosis, leaf bronzing, leaf thicken-
ing, stunting, loss of apical dominance and occasionally a deeper green color
developed in the primary leaves at intermediate UV-B enhancement levels. Dr.
Kneull Hinson of the University of Florida who is a soybean geneticist indi-
cated Hardee soybean was one of the parent lines he had been propagating for
12 years which developed curled and wrinkled leaves, stunting and a bushy
form when grown under field conditions in Florida. Unless special attention
was given the plants, they did not survive and reproduce (Appendix 1-34). The
cause of this condition was unknown, other lines also showed the symptoms and
the inheritance patterns were elusive. The symptoms under field conditions
were similar to those observed on 'Hardee' soybeans grown at the Duke Univer-
sity Phytotron. Because of the similarities and the agricultural implications,
a larger scale experiment was undertaken with an amendment to the original
proposal. Dr. Hinson supplied seed of 19 different varieties for testing. It
was also observed that Dr. James Crawl of the University of Florida had among
his genetic lines of watermelon in his progeny trials lines that had a "disease"
with symptoms similar to those described for UV-B treated watermelon plants.
He supplied two numbered progeny from Charleston Gray watermelon crosses that
were prone to produce these symptoms under field conditions at the ARC; Leesburg,
Florida. These two plus a commercial source of Charleston Gray watermelon were
included with the 19 soybean varieties test trials in the Duke Phytotron.
III-2
-------
Materials and Methods
UV-B enhancement
The controlled environment chambers modified for at the Duke University
Phytotron were the same as those described in the screening test of 82 species
in Section II (Appendix 1-5). As in the first tests of the 82 species, 6
pots per variety x<;ere planted in each of 2 chambers per UV-B enhancement regime.
UV-B0/i,, were set for 0, 0.5, 1.0, 1.5 and 2.0 (Table 1). All varieties were
OCU
thinned for uniformity to two plants per pot after one week. The temperature
was set for 26ฐ/22ฐC day/night and the photoperiod, watering and fertilizer
schedules were as before. FS-40 sun lamps with filters for the UV-B enhance-
ment levels were established in the same manner as previously described and
protocal for filter changes were the same.
Height was measured twice a week beginning with the second week and the
plants were groxTO in the chambers for 4 weeks. At harvest, data taken on a
per pot basis included: 1) total fresh and 2) dry weight, 3) leaf fresh and
4) dry weight, 5) stem fresh and 6) dry weight, 7) root fresh and 8) dry
weight, 9) % leaves, 10) % stems, and 11) % roots, 12) leaf area, 13) root:
shoot ratio, 14) leaf density, 15) a chlorosis rating of 0-9 and 16) final
height. Treatment means and statistical analyses for these parameters to
isolate differences among the 5-radiation levels were conducted. In addition,
the varieties were ranked by Duncan's Multiple range test for 14 parameters to
indicate varietal differences to any given parameter.
A photographic record was made of sample plants of each variety at each
UV-B (Appendix 1-23 to 27), as well as comparison photographs of different.
varieties from each of the UV-Bseu's (Appendix 1-28-30). Individual and
comparison photographs were also taken of the three watermelon varieties
(Appendix 1-32, 33).
III-3
-------
Results
Visual symptoms of the soybeans grown under enhanced UV-B radiation were
similar with variations in intensity depending upon the UV-Bseu (Tables 2-36).
Stunting and interveinal chlorosis were the first symptoms to appear, followed
by convex leaf cupping (Appendix 1-31). Later in development buds in the
axils of the primary leaves began to grow out and this response was very UV-B-
dose responsive (Appendix 1-23). Soybeans grown at 2.0 UV-Bgeu showed decreased
apical dominance the earliest and the lateral shoots had the greatest exten-
sion at the end of 4 weeks.
Within the soybean varieties, the percent reduction in biomass as compared
to the control ranged from 27 (Button) to 60% (Jupiter) and sensitivity ratings
were made similar to those given the 82 agricultural species in section 2.
Overall biomass reduction by UV-B treatment was very obvious just from
casual inspection of the chambers (Appendix 1-23). Within the soybean varie-
ties the percent reduction in biomass as compared to the control ranged from
27 (Hutton) to 60% (Jupiter) and sensitivity ratings were similar to those
given the 82 agricultural species in section 2. Varieties showing less than
a 30% reduction were classified as moderately sensitive 30-50% as sensitive
and greater than 50% reduction in biomass were highly sensitive. Hutton
and Cobb varieties were the least sensitive '(Tables 7,8). Combining all UV-B
enhancement regimes, the Altona variety had the greatest biomass and Santa
Maria the least (Table 9).
Leaf densities were increased from 74 (Hutton) to 223% (Bossier) above
the mylar control (Tables 10, 11). However, the relative amount of increase
did not correspond to reductions in biomass. That is, varieties with low
reductions in biomass did not necessarily have thicker leaves.
Soybean varieties with the least reduction in biomass also tended to have
III-4
-------
the least reduction in leaf area (Tables 12, 13), leaf dry weight (Tables 14,
15) stem dry weight (Tables 16, 17) and root dry xveight (Tables 18, 19). Mean
reductions for these parameters ranged from 44 (Button) to 78% (Acadian) for
leaf area, 10 (Cobb) to 49% (Acadian) for leaf dry weight and 49 (Hutton) to
73% (Hardee) for stem dry weight and 24 (Hutton) to 65% (Jupiter) for root dry
weights. On a dry weight basis, stems were most affected, then roots and
finally, dry weight of leaves.
Biomass was partitioned into leaves at the expense of stems and roots
(Table 20). The percent increase in leaves over the respective Mylar control
ranged from 14 (Biloxi) to 38% (Bossier) (Tables 21, 22) and for. stems from
17 (Biloxi) to 42% (Hardee) (Tables 23, 24). The percent root values ranged
from 14% less than the control (Santa Maria) to 37% more than the control
(Acadian) (Tables 25, 26). Thus, root response was highly variable, sometimes
increasing or decreasing depending upon the variety. This was reflected in
the root: shoot ratio which ranged from a decrease of 19% (Jupiter) below the
respective Mylar control to 48% (Acadian) above (Tables 27, 28). As a general
rule, the varieties with the least reduction in biomass showed an increase in
% roots and an increase in root:shoot ratio.
Each soybean was given a leaf chlorosis rating from 0 to 9 based on the
amount of leaf surface showing chlorosis (Tables 29, 30). All varieties became
chlorotic to some degree with the mean ratings ranging from 4.5 (Hutton) to 8.5
(Acadian). None of the controls demonstrated any chlorosis. Species with the
"highly sensitive" rating also showed more chlorosis and vice versa.
Height was increasingly reduced the longer the soybeans were grown in the
chambers. At the end of 2 weeks percent reductions ranged from 10 (Seminole)
to 35% (Mineira), (Tables 31, 32) 30 (Biloxi) to 55% (Altona) (Tables 33, 34)
at the end of 3 weeks and 42 (Biloxi) to 63% (Altona) (Tables 35,36) at harvest
III-5
-------
at the end of A weeks. However, height reductions did not necessarily follox*
.;biomass reductions.
The watermelon varieties were slow growing in the Phytotron chambers and
-although UV-B treated plants were reduced in every parameter, the relative
sensitivity should be more accurately defined in future studies of a longer
duration. Soms cotyledons became brown and curled and leaf expansion was
completely inhibited (Appendix 1-32, 33). The small amount of growth made
measurements difficult and a sensitivity rating system with this data would
be inappropriate. Data and statistical analysis for the various parameters
are included on tables with the soybean varieties.
Discussion
In looking for threshold effects using the parameters measured, it appeared
that the 0.5 UV-Bseu was greater than threshold under the controlled environ-
ment chamber conditions even for species showing the least reductions in bio-
mass, i.e., Button, Cobb, Hood, Biloxi. The low of a 17% reduction in biomass
can hardly be considered threshold. The abscence of normal plants at any
UV-Bgeu regime was probably due to increase sensitivity to the UV-B levels
in the lovr photosynthetically active radiati9n (PAR) levels in the chambers,
ranging from I70to240 . Without sufficient photoprotection which occurs at
the higher wavelengths and at higher intensities, accumlative UV-B damage
severely limited growth of the soybean varieties.
Plant responses to UV-B radiation were not linear. Decreases appeared to
fall into two groups with the percent reductions below the Mylar control being
similar for 0.5 and 1.0 UV~I>seu and then greater, but similar in magnitude at
1.5 and 2.0 UV-Bseu. This suggests a stepwise sensitivity to UV-B radiation
and probably occurs as more anabolic functions become affected, either as a
III-6
-------
result of increases in dose or reciprocity reactions related to duration of
the type without adequate photorepair.
Although the PAR levels in the growth chambers were low in relation to
full sunlight, the present study has provided important information for soybean
physiologist', breeders and growers who may be interested in introducing new
varieties. That there was a difference in sensitivity to UV-B radiation was
quite evident.
Leaf, stein and root data indicated large genetic differences in biomass
production just among the Mylar control plants (Appendix 1-27 to 30) (Tables 2
to 6). Soybeans which were large under Mylar or low light were not necessarily
those with the loxver percent reductions in biomass or the higher sensitivity
ratings. Significant differences among the varieties in sensitivity to UV-B
were found. Also, significant varietal differences were found for every para-
meter measured at every UV-B radiation level. With leaf density within any
given UV-B irradiance level, the leaf density of all varieties had less of a
difference than among the radiation regimes. A marked difference in leaf
density occurred between the Mylar controls and the 0.5 UV-Bseu level. Increases
in response to UV-B radiation was also evident.
A loss of apical dominance of buds in the axils of primary leaves was
observed to be dependent upon the UV-B enhancement level, although this
parameter was not measured quantitatively. For many of the varieties one could
predict the UV-B under which the plant had grown by the length of the shoots
from axillary buds of the primary leaves (i.e. see Altona, Davis, Hood, Button,
Jupiter and other varieties in Appendix 1-23-26 for varietal comparisons among
UV-B radiation levels). Under the field situation, a bushier plant with more
above ground biomass and a reduced root system could result from these respon-
ses. If this was the case, yield of beans would probably decrease.
Overall biomass was reduced and this was accompanied by a shift in biomass
III-7
-------
partitioning. For every variety, the % biomass in leaves was increased and
the % in stems decreased. The latter is the usual stunting response. However,
in approximately two-thirds of the varieties, the % biomass found in roots was
decreased.
This could have serious consequences for a crop which is usually grown
.withoug irrigation from two standpoints. First, non-irrigated plants may have
reduced yields. Secondly, increased irrigation may occur. In the mid-south
and south, soybeans are irrigated if they are grown where facilities are
available for irrigating cotton or rice. Also, some soybeans are irrigated in
drier regions such as Nebraska. At this time, the decision to irrigate is not
based on whether irrigation will increase yields but whether it will increase
profits. A reduced root system due to increases in UV-B levels might necessi-
tate irrigation and aggravate already short water supplies in some areas of the
United States.
The shift to a short statured plant under enhanced UV-B radiation levels
might allow maor northerly indeterminate type soybean characters to be bred
into varieties for the south to decrease lodging. However, this would probably
have to come via a genetic breeding program because soybean adaptability is
very zone specific.
Thus, in light of the significant differences found among soybean varie-
ties in sensitivity to UV-B radiation, it should become yet another factor to
be evaluated in a soybean breeding program.
-------
Table 1. Light quality in "C" chambers at the Duke University
Fhytotron.
o
Photosynthetically Active Radiation
IJV-B seu1
0.036
0.007
0.540
0.500
1.120
1.070
1.460
1.570
2.050
2.050
mil CA
Filter^
M
M
10+10
10+10
10
10
3+5
3+5
5
5
Cool White
Lights Only
200
240
235
240
225
230
180
230
235
210
Cool White
+ FS - 40
205
245
240
245
230
235
185
235
240
215
UV-B defined in Section I.
seu
M = mylar type S, 5 and 10 are mil thicknesses of cellulose
acetate (CA).
3
Photosynthetically active radiation measured in microeinsteins
-2-1
m sec
III-9
-------
Table 2 . Ranking of soybean varieties, high to low, by Duncans Multiple Range Test for 13 different
parameters under Mylar Control for UV-B enhancement radiation treatments.
H
H
No. Soybean Var.
l=Acadian
2=Americana
3=Altona
4=Biloxi
5=Bossier
6=Centenniai
7=Cobb
8=Davis
9=Forrest
10=Hood
ll=Hutton
12=Jupiter
13=Mineira
14=0tootan
15=Pickett
16=Roanoke
17=Santa Maria
18=Seminole
19=Hardee
Watermelon
1=CGFL. 77-1
2=CGFL. 77-2
3=Charl. Gray
Var Leaf Area
No. (cm^)
3 A 385
6 A 377
4 A 372
18 A 364
13 B 300
15 B 297
1 BC 285
9 BCD 262
2 BCD 262
12 BCD 256
7 BCD 244
10 BCD 243
14 CD 231
17 CD 224
8 CD 222
16 D. 218
5 D 218
19 D 217
. 11 D 198
3 A 19
2 A 19
1 A 18
Var Leaf Dry
No. Wt. (g)
18 A .833
4 AB .771
2 ABC .738
15 BCD .669
6 BCD .668
13 B-ปE .651
12 B->E .626
10 C+F .586
11 D-KJ .539
9 D+G .528
1 D-*G .528
19 D-ปH .512
3 D+H .508
16 E+H .498
17 FGH .458
14 FGH .442
7 FGH .432
8 GH .400
5 H .360
1 A 1.118
2 A 1.085
3 A 1.074
Var Root Dry
No. Wt. (g)
18 A .405
2 AB .374
6 AB .364
4 AB .350
13 AB .347
12 AB .343
15 ABC .328
10 BCD .272
16 CDE .253
11 DEF .225
9 D-K; .220
7 D-K; .204
8 D-K; .197
3 D+H .191
19 E-ปH .178
1 E+H . 168
14 E+H .161
5 FGH .158
17 FGH .155
3
2
1
A
A
A
.248
.218
.176
Var
No.
2
6
4
3
12
18
13
15
9
1
10
11
7
17
16
5
14
19
8
1
2
3
Stem
Wt.
A
B
B
BC
BC
BCD
BCD
CDE '
DE
EF
EF
EF
EFG
E+H
E->H
FGH
GHI
HI
HI
A
AB
B
Dry
(*>
.655
.555
.532
.495
.493
.482
.480
.423
.412
.406
.401
.386
.361
.-355
.348
.333
.308
.284
.281
.348
.301
.209
UV-B enhancement defined in section 1.
-------
Table 2 . Continued
Var
No.
11
10
12
19
16
18
15
13
17
4
6
9
3
2
14
1
8
7
5
Density
(g/dm2)
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
.28
.24
.24
.24
.23
.23
.22
.22
.21
.21
.20
.20
.19
.19
.19
.18
.18
.18
.17
Var
No.
19
14
18
1
- - 17
15
4
10
16
11
8
9
13
7
12
3
6
5
2
% Leaf
A
B
B
BC
BC
BC
BCD
B+E
B->F
B->-F
B-K;
BT>G
B-K;
C-K;
C-K;
D->G
EFG
FG
G
53
49
48
47
47
47
47
47
46
46
46
46
44
43
43
42
42
42
42
Var
No.
18
13
12
6
15
8
16
10
2
4
7
11
9
5
19
14
3
17
i
% Root
A
AB
ABC
ABC
ABC
ABC
ABC
A->D
A->D
A+E
A>E
A+F
C-s-F
C->F
C->G
D-KJ
E+H
E+H
FGH
24
23
23
22
22
22
21
21
21
20
20
20
18
18
18
17
16
16
15
1 A .65
2 A . .59
3 A .58
2 A 68
1 A 68
3 A 67
3 A
2 AB
1 B
19
14
12
Var
No.
3
5
2
1
17
7
9
6
14
12
11
4
13
16
10
8
15
19
18
1
2
3
% Stem
A
AB
BC
BC
BC
BCD
B+E
C+F
C+F
C-K;
C-K;
D->G
D-K;
D-Hl
E+H
FGH
GHI
HI
I
A
AB
B
42
40
37
37
37
36
36
35
35
34
34
33
33
32
32
32
31
29
28
20
18
14
Var
No. R/S Ratio
18 A .315
13 A .305
12 AB .297
15 AB .293
6 AB .292
8 AB .287
16 A-H3 .274
10 A+D .274
2 A+D .271
4 A-HS .258
7 A+E .257
11 A->E .248
9 A+F .228
5 A+F .226
19. A+F .224
14 B+F .206
3 C+F .190
17 C+F . .188
1 DEF .183
3 A .253
2 A .160
1 A .137
-------
Table 2. Continued
Var
No.
2
18
4
6
13
12
15
10
3
9
11
1
16
7
19
17
14
8
5
Dry
Wt.
Biomass(g)
A
AB
ABC
ABC
BCD
BCD
CDE
DBF
EFG
E+H
FGH
F->I
F+I
F+I
G-M
G->J
G->J
HIJ
IJ
1.767 .
1.719
1.653
1.588
1.478
1.462
1.420
1.258
1.194
1.160
1.150
1.103
1.099
0.997
0.973
0.968
0.911
0.878
0.850
Var
No.
3
2
4
13
6
1
12
11
10
9
7
16
17
5
' 8
18
15
14
19
Height 2
(mm)
A
A
B
B
B .
C
C
CD
CD
CD
D
E
E
EF
EF
EF
FG
FG
G
183
178
156
151
151
134
134
128
127
126
121
107
105
99
96
95
90
87 .
79
Var
No.
3
2
13
4
1
6
7
12
9
5
10
11
17
14
16
8
15
18
19
Height 3
(mm)
A
B
C
C
CD
CD
CD
CDE
DE
EF
FG
G
G
GH
GH
GH
GH
H
r-
374
301
270
270
262
258
257
248
242
229
211
204
204
189
187
186
185
172
141
Var
No.
3
13
2
4
9
1
6
7
12
14
5
17
11
10
15
16
8
18
19
Height 4
(mm)
A
B
BC
BCD
BCD
CDE
CDE
DEF
DEF
EF
FG
FG
GH
GH
GH
H
H
H
I
495
415
406
380
379
376
373
357
353
341
330
327
301
299
293
287
282
276
237
Var
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Chlorosis
Rating 0-9
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
2
3
A
A
A
1.654
1.604
1.531
1
2
3
A 26
B 21
B 19
1 A 26
2 B 20
3 B 19
1 A 32
2 B 24
3 B 24
1
3
2
A 7.8
A 6.4
A 6.3
-------
u>
Table 3. Ranking of soybean varieties, high to low, by Duncans Multiple Range Test for 13 different
parameters under UV-B enhancement radiation treatment 2.
No. Soybean Var.
l=Acadian
2=Americana
3=Altona
4=Biloxi
5=Bossier
6=Centennial
7=Cobb
8=Davis
9=Forrest
10=Hood
ll=Hutton
12=Jupiter
13=Mineira
14=0tootan
15=Pickett
16=Roanoke
17=Santa Maria
18=Seminole
19=Hardee
Var
No.
2
15
6
18
4
7
13
10
- 16
11
9
12
17
19
3
14
8
5
1
Leaf Area
(cm2)
A 262
B 197
B 194
BC 185
BC 185
BC 178
BC 174
BC 174
BCD 157
CD 150
CD 149
DE 124
EF 108
EF 107
EF 97
EF 95
EF . 93
EF 86
F 80
Var
No.
2
18
4
15
11
13
6
10
9
16
7
12
19
14
17
8
3
5
1
Leaf
Wt.
A
AB
ABC
ABC
A->D
A+D
A->D
A-ปE
A->F
A->F
B-K;
C-K;
D-K;
EFG
EFG
FG
G
G
G
Dry
(s)
.621
.593
.579
.578
.525
.518
.503
.490
.475
.475
.431
.401
.351
.322
.321
.309
.289
.286
.258
Var
No.
2
4
6
15
16
10
18
9
13
7
11
3
12
8
14
1
5
19
17
Root
Wt.
A
B
BC
BC
BCD
B+E
B->E
B-HF
B+F
C-ปG
C-K;
D-H3
E->H
FGH
GHI
GHI
HI
HI
I
Dry
(S)
.312
.237
.226
.213
.202
.197
.189
.180
.169
.161
.160
.136
.131 .
.128
.101
.098
.090
.068
.061
Var
No.
2
4
6
15
16
11
10
13
7
9
18
12
17
3
14
8
5
19
1
Stem
Wt.
A
B
BC
DE
DE
DE
DE
DE '
DE
EF
EF
EFG
FGH
GHI
HIJ
HIJ
HIJ
IJ
J
Dry
(g)
.383
.328
.316
.251
.236
.234
.229
.228
.228
.215
.210
.202
.163
,150
.138
.128
.118
.097
.092
Watermelon
1=CGFL.77-1
2=CGFL.77-2
3=Charl. Gary
1
3
2
A
A
A
22
20
19
1
2
3
A
A
A
1.078
0.984
0.926
3
1
2
A
A
A
.197
.128
.124
1
2
3
A .274
A .213
A .208
1
UV-B enhancement defined in section 1.
-------
Table 3 . Continued
H
H
Var
No.
5
14
11
19
12
4
8
18
16
9
1
17
15
3
13
10
6
7
2
1
2
3
Density
(g/din2)
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
.60
.37
.36
.35
.34
.34
.34
.34
.33
.33
.33
.33
.31
.31
.30
.28
.26
.24
.24
.56
.54
.52
Var
No. % Leaf
19 A 67
18 B 60
5 B 60
17 B 59
14 BC 58
1 BC 58
11 BC 57
13 BC 57
15 BCD 56
12 B-ปE 55
8 B->E 55
9 B+E 55
10 B+E 55
7 C->F 53
16 C+G 53
4 D->G 51
3 EFG 51
6 FG 48
2 G 48
2 A 75
1 A 72
3 A 68
Var
No.
3
2
1
8
6
16
4
9
15
7
10
18
13
14
12
5
11
19
17
% Root
A
A
AB
AB
AB
AB
AB
AB
AB
ABC
ABC
ABC
BC
BC
BC
BCD
BCD
DEF
EFG
23
23
22
22
22
21
20
20
20
20
20
19
18
18
18
17
17
13
11
Var
No.
17
6
2
4
7
12
3
16
11
10
13
9
14
15
5
. 8
18
1
19
% Stem
A
A
AB
ABC
Ar>-D
B+E
C+F
C->G
D^C
D-K;
D->G
D+G
EFG
E+H
FGH
GHI
HIJ
IJ
JK
30
30
29
29
28
27
26
26
26
26
25
25
24
24
23
23
21
21
20
Var
No.
3
2
8
1
6
16
4
9
10
15
7
18
13
14
12
5
11
19
17
R/S
A
AB
ABC
ABC
ABC
ABC
BC
BC
BC
BC
BCD
BCD
BCD
BCD
BCD
BCD
CDE
DEF
EF
Ratio
.353
.307
.28:6
.283
.278
.276
.259
.255
.252
.252
.249
.232
.225
.220
.218
.213
.208
.157
.122
3 A
2 B
1 B
15
9
9
1 A 19
3 A 17
2 A 16
3 A .195
2 B .102
1 B .097
-------
Table 3. Continued
M
H
Var
No.
2
4
6
15
18
11
10
13
16
9
7
12
3
8
14
17
19
5
1
Dry
Wt.
Biomass(g)
AB
BC
CD
CD
CDE
CDE
CDE
CDE
CDE
DE
DE
EF
FG
FG
FG
FG
FG
FG
G
1.316
1.144
1.044
1.042
0.993
0.919
0.916
0.916
0.913
0.870
0.819
0.733
0.575
0.564
0.560
0.544
0.516
0.493
0.448 .
Var
No.
4
2
3
6
1
12
10
11
9
13
17
7
18
15
16
5
14
8
19
Height 2
(mm)
A
A
B
B
C
C
CD
CD
CD
DE
DEF
EFG
E+H
FGH
FGH
GHI
HI
I
J
156
153
141
140
121
121
115
112
111
108
107
99
98
97
97
89
88
85
72
Var
No.
2
4
3
6
12
7
9
10
11
1
17
13
15
16
18
5
8
14
19
Height 3
(mm)
A
AB
B
B
C
D
D
D
D
DE
DE
DEF
EFG
FGH
GHI
HI
HI
I
J
224
216
206
205
182
166
166
165
163
158
158
152
148
142
137
131
130
128
102
Var
No.
2
6
4
12
3
7
10
9
11
13,
16
15
17
1
18
14
8
5
19
Height 4
(mm)
A
A
AB
BC
CD
CDE
CDE
C->F
DEF
EFG
EFG
FGH
GHI
HI
HIJ
HIJ
IJ
J
K
256
249
247
228
221
214
210
207
204
193
193
185
181
171
168
165
162
148
119
Var Chlorosis
No. Rating 0-9
1 A 8.0
3 AB 7.1
4 BC 6.1
9 CD 5.0
5 CD 5.0
14 CD 4.8
18 CD 4.7
17 CD 4.5
6 CDE 4.4
19 CDE 4.4
8 DE 4.0
15 DE 3.7
12 DE 3.4
7 DE 3.4
16 DE 3.3
10 DE 3.2
11 DE 3.1
13 DE 3.1
2 E 2.5
1 A 1.480
3 A 1.331
2 A 1.321
1 A
2 B
3 B
25
21
21
1 A 27
2 B 21
3 B 20
1 A
3 AB
2 B
34
27
25
1 A
3 A
2 A
5.1
4.6
4.4
-------
Table
M
M
M
I
4. Ranking of soybean varieties, high to low, by Duncans Multiple Range Test for 13 different
parameters under UV-B enhancement radiation treatment 3.
Var Leaf Area
No. Soybean Var.
l=Acadian
2=Americana
3=Altona
4=Biloxi
5=Bossier
6=Centennial
7=Cobb
8=Davis
9=Forrest'
10=Hood
ll=Hutton
12= Jupiter
13=Mineira
14=0tootan
15=Pickett
16=Roanoke
17=Santa Maria
18=Seminole
19=Hardee
Watermelon
1=CGFL. 77-1
2=CGFL. 77-2
3=Charl.' Gray
No.
2
6
13
18
4
15
11
. - .7
" ' '10
9
16
8
5
12
3
17
14
1
19
1
2
3
(cm"
A
B
BC
BC
BCD
BCD
BCD
CD
DE
DEF
EFG
EFG
GHI
GHI
GHI
' HI
HI
I
I
A
A
B
194
154
147
144
136
132
131
127
117
113
98
89
80
78
76
70
69
62
60
17
16
10
Var Leaf Dry
No. Wt. (g)
2 AB .657
4 BC .562
18 CD .553
6 CDE .515
11 CDE .505
13 OF .476
15 C->G .463
7 C->H .451
10 D->H .443
9 E-KL .411
16 F-M .383
8 F-M .378
5 F+J .363
3 G-HJ . 353
12 H->K .341
9 UK .319
1 JK .292
14 K .239
17 K .237
2 A 1.032
1 AB 0.901
3 B 0.750
Var
No.
2
10
11
18
6
4
13
7
8
16
15
1
5
3
9
12
19
14
17
Root
Wt.
A
B
BC
BC
BC
BC
BCD
B+F
C->F
C-*F
DBF
D-K;
D-H3
E->H
FGH
FGH
GHI
HI
I
Dry
H
FGH
GH
GH
HI
HI
IJ
J
Dry
00
.298
.287
.256
.208
.203
.183
.175
.173
.173
.161
.154
.145
.132
.123
.121
.113
.111
.083
.076
1
2
3
A .155
A .147
B .113
1 A .253
2 B .188
3 C .116
1
UV-B enhancement defined in section 1.
-------
Table 4. Continued
Var
No.
19
3
12
1
5
16
4
8
11
14
18
10
9
17
15
7
13
6
2
Density
(g/dm2) .
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
.55
.48
.48
.48
.47
.43
.43
.43
.41
.41
.41
.40
.38
.37
.37
.36
.35
.34
.34
Var
No .
19
15
14
18
9
12
13
17
16
11
8
1
7
10
3
5
2
4
6
% Leaf
A
ABC
BCD
B+E
C+F
D-KJ
D+H
D+H
D+H
D+H
E+H
FGH
FGH
FGH
GH
GH
GH
H
H
69
66
63
62
61
60
59
59
59
57
57
57
56
56
56
55
55
54
54
Var
No.
1
10
16
8
18
2
11
13
6
12
7
5
4
3
15
14
9
19
17
% Root
A
AB
ABC
ABC
A->D
A->D
A+E
A+E
A-HF
B-+G
C-K;
C-K;
C-K;
D+J
D-K;
E+H
FGH
GHI
HIJ
22
22
21
21
20
20
20
20
19
18
18
17
17
17
17
16
15
15
13
Var
No.
4
17
5
3
6
7
2
9
11
10
8
12
14
13
1
16
18
15
19
% Stem
A
A
AB
AB
AB
ABC
BCD
CDE
DE
DE
DE
E
E
E
E
EF
FG
G
GH
28
28
28
27
27
26
25
23
23
22
22
22
21
21
21
20
17
17
16
Var
No. R/S Ratio
10 A .298
1 A .288
16 AB .270
8 AB .268
11 ABC .256
18 ABC .256
2 ABC .255
13 ABC .248
6 A+D .237
12 BCD .223
7 BCD .217
5 B-vE .212
4 B+E .211
. 3 B->E .209
15 B+E .207
14 CDE .194
9 DEF .184
19 DEF .177
17 EF .154
3 A .79
2 AB .68
1 B .58
3 A 77
2 A 75
1 B 67
1
3
2
A 13
A 12
A 11
1 A
2 B
3 B
21
14
12
1 A .151
3 A .134
2 A .128
-------
table 4. Continued
M
1-1
M
1
M
oo
Var
No.
2
4
6
11
18
10
13
7
15
9
8
5
16
3
12
1
19
17
14
Dry Wt.
Biomass(g)
A
B
BC
BC
BC
CD
CD
CD
DE
DEF
DEF
.DEF
DEF
EF
EFG
FGH
GH
H
H
1.203
1.027
0.951
0.893
0.890
0.810
0.811
0.803
0.709
0.674
0.663
0.661
0.654
0.634
0.564
0.518
0.467
0.402
0.386
Var Height 2
No. (mm)
4 A 141
2 AB 134
3 AB 134
6 B 128
1 C 116
12 D 105
9 D 105
13 DE 101
11 DBF 99
10 DEF 96
5 D->G 95
7 D-KJ 94
17 E+H 90
18 FGH 90
8 GHI 85
16 HI 83
15 IJ 76
14 IJ 75
19 J 71
Var Height 3
No. (mm)
4 A 196
6 B 177
2 B 177
3 B 173
12 C 148
7 CD 142
9 CD 140
11 CD 139
ID 137
17 DE 133
13 DE 132
10 DE 131
5 EF 125
18 EF 124
8 FG 119
16 FG 117
15 GH 110
14 H 100
19 I 86
Var Height 4
No. (mm)
4 A 227
6 AB 219
2 B 208
3 C 187
7 C 186
11 CD 174
12 D 171
10 D 169
9 DE 165
13 DE 163
17 EF 154
1 F 146
18 F 145
8 F 144
5 F 144
16 F 142
15 G 129
14 G 120
19 H . 91
Var Chlorosis
No. Rating 0-9
1 A 8.9
3 A 8.9
4 AB 7.2
19 BC 6.3
18 . BC 6.2
14 BC 6.0
2 BCD 5.8
5 C+F 4.9
12 C-ปF 4.9
17 C->F 4.8
8 C-ปF 4.4
9 C-ปF 4.4
16 DEF 4.0
6 DEF 3.9
7 EF 3.4
13 EF 3.4
10 EF 3.2
11 EF 3.2
15 F 3.1
2
1
3
A
A
B
1,511
1.335
1.277
1
2
3
A 24
B 18
B 18
1 A 24
3 B 19
2 B 16
1 A 28
2 B 21
3 B 20
1 A
3 A
2 A
5.4
5.2
5.1
-------
H
M
I
I-1
Table 5. Ranking of soybean varieties, high to low, by Duncans Multiple Range Test for 13 different
parameters under UV-B enhancement radiation treatment 4.
No. Soybean Var.
l=Acadlan
t
2=Americana
3=Altona
4=Biloxi
5=Bossier
6=Centennial
7=Cobb
8=Davis
9=Forrest
10=Hood
ll=Hutton
12=Jupiter
13=Mineira
14=0tootan
15=Pickett
16=Roanoke
17=Santa Maria
18=Seminole
19=Hardee
Var
No.
2
18
4
11
6
10
15
7
13
12
16
8
1
9
3
5 '
14
17
19
Leaf Area
(cm2)
A
B
BC
BC
CD
DE
DE
DE
DE
DE
EF
FG
GH
GH
GH
GH
HI
HI
I
87
68
66
65
58
56
54
53
51
51
47
41
36
35
35
34
31
30
23
Var
No.
2
4
11
18
10
6
15
13
12
16
7
3
9
8
5
1
19
14
17
Leaf
Wt.
A
AB
AB
AB
ABC
BC
CD
CD
CDE
C-ปF
C-ปF
D->G
D->G
D->H
E-ปH
FGH
GH
GH
H
Dry
(?)
.427
.415
.404
.398
.355
.343
.318
.312
.308
.295 .
.289
.261
.261
.244
.228
.218
.188
.182
.176
Var
No.
2
11
18
6
4
13
16
10
15
12
7
9
8
1
3
5
19
14
17
Root
Wt.
.A
ABC
ABC
ABC
ABC
BCD
B+E
B-ปE
C->F
D-K3
EFG
FG
FG
GH
GHI
HIJ
IJ
IJ
J
Dry
(g)
.201
.173
.170
.168
.166
.163
.159
.158
.145
.128
.125
.120
.117
.099
.093
.082
.063
.063
.055
Var
No.
2
4
6
11
10'
7
12
1
18
9
3
13
15
16
8
5
17
14
19
Stem
Wt.
A
B
BC
CDE
D-*G
E+H
E-ปH
'E->I
E-H
F-KE
GHI
GHI
G->J
G->J
H+K
UK
JKL
KL
L
Dry
(8)
.233
.198
.183
.159
.139
.127
.126
.122
.121
.117
.110
.110
.103
.103
.093
.085
.068
.063
.038
Watermelon
1=CGFL.77-1
2=CGFL.77-2
3=Charl. Gray
1 A
2 A
3 A
10
10
8
2 A .746
1 A .679
3 A .657
2 A .194
1 A .179
3 A .163
3 A .165
1 A .164
2 A .150
1
UV-B enhancement defined in section 1.
-------
Table 5. Continued
Var Density Var Var Var Var
No._ (g/dm2) No. % Leaf No. 2 Root No. % Stem No. R/S Ratio
19 A .31 19 AB 66 16 A 28 1 A 27 ~16~ A 7407
3 A .76 17 BC 61 13 AB 28 6 A 27 13 AB .392
9 A .75 14 C 60 8 ABC 26 2 AB 26 8 ABC ,351
5 A .67 5 CD 58 15 A*D 25 4 ABC 26 15 ABC ,347
10 A .66 18 CD 58 18 A-ป-D 24 3 A+D 24 18 A+D .330
1 A .64 3 CDE 56 6 A->E 24 7 A-H) 24 6 BCD ,322
12 A .63 15 CDE 56 10 A->F 24 9 A+E 23 10 BCD .319
11 A .63 11 CDE 56 9 B-ป-F 24 12 B+F 22 9 B+E ,314
E 16 A .63 12 CDE 55 2 C+F 23 17 C-KJ 21 1 B+E .313
V 4 A .63 10 C+F 55 11 C-XJ 23 11 C-H5 21 2 B+E .308
S 13 A .62 8 DEF 54 7 C-ปG 23 10 C+C 21 11 C+F .303
17 A .60 13 DEF 54 12 C-*H 23 5 C-H3 21 7 C-vF .302
- 8 A .60 7' DEF 53 1 C-ป-I 22 8 D-ปH 20 12 C+F .295
18 A .60 4 DEF 53 19 C-*J 21 14 D-HH 20 19 C->G .277
15 A .59 9 DEF 53 4 C-*J 21 15 E-"I 19 4 C-K5 .270
6 A .59 16 DEF 53 5 D->J 21 16 E+I 19 5 C-ปG ,265
1* A .58 1 EF 50 14 E+J 20 13 E+I 18 14 D^C .249
7 A .55 2 EF 50 3 F-M 19 18 F-M 17 3 D-H5 .248
2 A .50 6 F 49 17 HIJ 18 19 J 13 17 FG .221
3 A .90 -2 A 67 2 A 18 3 A 17 2 A .231
2 .AB .79 3 A 66 1 A 18 1 A 16 1 A .220
1 B .70 1 A 66 3 A 17 2 A 14 3 A .206
-------
Table
5. Continued
M
M
M
1
to
M
Var
No.
2
4
11
6
18
10
13
15
12
16
7
9
3
8
1
5
14
17
19
Dry Wt.
Biotnass (g)
A
AB
BC
BCD
BCD
CDE
DEF
EFG
EFG
EFG
E->H
F->I
GHI
GHI
HI
IJ
J
J
J
.860
.779
.736
. 695 7 "'
.689
.652
.584
.566
.562
.557
.541
.498
.463
.453
.439
.395
.308
.298
.289
Var
No.
4
2
6
3
1
12
11
9
13
10
7 '
17
18
5
16
14
8
15
19
Height 2
(nan)
A
AB
BC
C
C
C
D
D
DE
DE
DEF
EF
EF
FG
FG
FG
FG
G
H
129
122
113
111
108
104
93
92
90
89
82
81
81
77
77
75
72
69
56
Var Height 3
No. (mm)
4 A 171
2 B 158
6 C 143
3 C 141
12 CD 137
11 CDE 132
1 DE 127
17 EF 121
10 EF 120
9 FG 114
13 FGH 113
7 F+I 111
18 F-KL 110
5 G+J 102
8 G-*J 102
16 HIJ 101
14 IJ 99
15 J 94'
19 K 74
Var Height 4
No. (mm)
4 A 211
2 B 184
6 C 153
3 CD 149
12 CD 149
11 CD 146
10 DE 141
17 EF 135
1 EF . 135
18 FG 130
7 FG 127
13 FGH 126
9 GHI 122
16 HIJ 117
8 UK 113
5 JK 111
14 JK 110
15 K 104
19 L 84
Var Chlorosis
No. Rating 0-9
14 A 9.0
17 A 8.8
3 A 8.7
19 A 8.6
4 AB 8.5
18 ABC 8.3
1 ABC 8.3
9 BCD 7.7
16 CD 7.5
6 DE 7.4
7 DEF 7.2
5 DEF 7.1
8 EKG 6.8
2 E+H 6.6
13 F-KE 6.4
15 F->I 6.3
10 GHI 6.2
12 HI 6.0
11 I 5.8
2 A 1.090
1 A 1.022
3 A 0.985
1 A
2 B
3 B
23
18
17
1 A 22
3 B 19
2 B 18
1 A 23
2 B 19
3 B 18
2 A 9.0
3 A 9.0
1 A 8.9
-------
Table 6. Ranking of soybean varieties, high to low, by Duncans Multiple Range Test for 13 different
1
parameters under UV-B enhancement radiation treatment 5.
M
H
M
NJ
NJ
No. Soybean Var,
l=Acadian
2=Americaria
3=Altona
4=Biloxi
5=Bossier
6=Centennial
7=Cobb
8=Davis
9=Forrest
10=Hood
ll=Hutton
12=Jupiter
13=Mineira
14=0tootan
15=Pickett
16=Roanoke
17=Santa Maria
18=Seminole
19=Kardee
Watermelon
1=CGFL.77-1
2=CGFL.77-2 .
3=Charl. Gray
Var Leaf Area
No. (cm2)
6 A 138
2 AB 119
15 B 114
18 BC 111
11 BCD 101
4 B+E 98
10 OF 91
13 OF 90
7 D->G 83
12 D-K? 78
5 E-+H 76
16 FG1I 75
1 FGH 74
9 F-KE 70
8 . G->J 66
3 G->J 60
17 HIJ 54
14 IJ 49
19 J 47
3 A 57
2 A 51
1 A 44
Var Leaf Dry
No. Wt. (g)
18 A .548
2 AB .481
11 AB .479
15 AB .476
4 ABC .468
6 ABC .453
10. BCD .422
13 B+E .400
16 B-HE .387
7 B->F .371
9 OG .351
12 IHG .333
8 D->G .310
1 D-K; . 303
5 EFG .298
3 EFG .295
19 EFG .288
17 FG .263
14 G .246
3 A
2 AB
1 B
.766
.649
.416
Var
No.
18
13
16
2
15
6
10
11
7
8
9
4
12
19
3
1
5
14
17
2
3
1
Root
Wt.
A
BC
BC
CD
CD
CD
CD
CDE
CDE
DEF
DEF
D-KJ
EFG
FGH
GH
H
H
H
H
A
A
A
Dry
<8>
.244
.186
.183
.173
.169
.168
.164
.153
.152
.140
.140
.134
.121
.102
.098
.079
.078
.063
.063
,197
.131
.102
Var Stem Dry
.No. Wt. (R)
2 AB .254
6 BC .239
4 BCD .217
11 CDE .190
18 CDE .190
10 OF . 182
9 D-ปG .178
15 D-*G .174
7 D-*G .171
13 D+G .171
12 D+H .157
16 E-M .143
3 E+I .142
5 ฃ*! . 130
17 E->I .130
8 F+I .125
1 GHI .122
14 HI .100
19 I .084
3 A .249
1 AB .190
2 B .166
UV-B enhancement defined in section 1.
-------
Table 6ป Continued
Var
No,
19
16
18
14
17
3
9
M A
i--i f
? 12
a s
n
10
13
5
7
15
1
2
6
Density
(g/dtn2)
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
.66
,56
.55
.54
.54
.52
,52
.51
.50
.50
.49
.49
,48
.46
,45
,44
,43
,42
,36
2 A
3 A
1 A
.21,
.21
.16
Var
No.
19
14
1
5
17
11
15
4
18
3
12
10
16
8
7
13
2
6
9
3
2
1
% Leaf
A 61
AB 60
ABC 59
A-HD 59
A-+D 59
A+E 58
A+E 58
A+F 57
B-KJ 56
C-K3 55
G-KJ 55
D-K5 55
D+G 54
EFG 54
FG 54
FG 53
FG 53
FG 53
G 52
A 64
A 63
A 58
Var
No.
16
18
13
8
. 7
10
19
9
15
6
12
2
11
3
4
1
14
5
17
2
1
3
% Root
A
AB
ABC
ABC
A-H)
BCD
BCD
BCD
CD
DE
DE
DE
DE
DE
EF
EFG
EFG
EFG
FG
A
A
A
26
25
24
24
22
21
21
21
20
19
19
19
19
18
16
16
15
15
13
19
15
13
Var
No.
17
2
6
3
9
4
12
5
1
14
7
10
11
13
8
15
16
18
19
% Stem
A
AB
AB
ABC
ABC
ABC
A->D
A->D
A->E
B-H3
B->E
C+F
C+F
EH-H
E->I
ฃ*!
G->J
HIJ
J
28
28
28
27
27
26
26
26
25
24
24
24
23
23
22
21
20
19
18
Var
No.
16
18
13
8
7
10
19
9
15
12
6
2
11
3
4
1
14
5
17
R/S
A
AB
ABC
ABC
A+D
BCD
BCD
B->E
C+F
D+H
D->H
D-vH
EH-H
D+I
E-KJ
F-M
G-KJ
HIJ
J
Ratio
.348
.330
.327
.325
.286
.275
.273
.268
.258
.242
.240
.237
.231
.223
.197
.192
.184
.180
.150
1 A
3 AB
2 B
28
23
18
2 A .280
1 A .177
3 A .152
-------
Table 6.. Continued
I
N>
.p-
Var
No.
18
2
6
11
4
15
10
13
16
7
9
12
8
3
5
1
19
17
14
Dry Wt.
Biomass(g)
A
AB
ABC
A-H)
A+D
A+D
B+E
B->E
C-*F
C->G
E->H
E+I
F-M
G+J
HIJ
HIJ
IJ
IJ
J
.982
.908
.860
.822
.819
. .819
.770
.757
.712
.693
.669
.611
.575
.535
.505
.503
.474
.456
.409
Var
No.
3
2
6
1
4
12
9
10
13
11
17
7
5
16
8
18
14
15
19
Height 2
(mm)
A
AB
AB
AB
B
C
C
CD
CD
D
D
E
EF
EFG
FG
FG
G
G
H
121
119
117
115
113
103
102
98
96
94
91
83
82
79
75
75
74
73
61
Var
No.
4
6
2
3
12
1
9
11
10
17
7
13
5
15
8
16
18
14
19
Height 3
(mm)
A
A
A
A
B
BC
BC
CD
CD
CD
DE
DE
EF
FG
FG
FG
FG
G
H
170
164
160
160
149
141
139
135
134
132
124
124
116
110'
109
108
105
102
77
Var Height 4
No. (mm)
6 A 202
4 AB 199
2 ABC 19G
3 A+D 176
12 BCD 172
9 B-vE 171
8 CDE 168
10 CDE 163
11 CDE 168
1 DEF 159
17 DEF 152
7 DEF 152
13 D+G 148
15 EFG 141
5 FG 134
16 FG 133
18 FG 132
14 G 121
19 H 87
Var Chlorosis
No. Rating 0-9
14 A 9.0
3 A 8.9
1 AB 8.8
4 ABC 8.5
9 A-KD- 8. 3
19 A->E 8.3
18 A+F 7.9
16 A->G 7.8
17 A+H 7.7
7 B->J 7.4
12 B-M 7.4
8 C->K 7.3
6 D+K 6.9
10 D+K 6.9
2 E+K 6.9
13 F+K 6.7
5 G+K 6.4
11 JK 6.1
15 K 5.9
_.3.._A 1.146
2 AB 1.012
1 B 0.708
1 A 26
2 A 26
3 A 24
1 A 50
3 A 39
2 A 39
1 A
3 A
2 A
62
59
56
1 A 0
2 A 0
3 A 0
-------
Table 7. Mean dry weight biomass in grams per pot by UV-B enhancement
regime-'- and corresponding percent reductions below the mylar
control (UV-B enhancement regime //I).
UV-B Enhancement Regime
Variety
Soybean
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Button
12. Jupiter
13. Mineira
14. Ottotan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Bardee
Watermelon
1. CGF177-1
2. CGF177-2
3. Charl. Gray
1
1.10
1.77
1.19
1.65
0.85
1.59
1.0
0.88
1.16
1.26
1.15
1.46
1.47
0.91
1.42
1.10
0.97
1.72
0.97
0.70
1.01
1.15
0
1
0
1
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
2
.44
.31
.58
.14
.49
.04
.82
.56
..87
.92
.92
.73
.92
.56
.04
.91
.54
.99
.52
.15
.13
.13
2-%
60
26
51
31
42
35
18
37
25
27
20
50
38
38
27
17
44
42
46
79
87
88
3
0.52
1.20
0.63
1.02
0.66
0.95
0.80
0.66
0.67
0.81
0.89
0.56
0.81
0.29
0.71
0.65
0.40
0.89
0.47
0.13
0.14
0.10
3-%
53
32
47
38
22
40
20
25
42
36
23
61
45
57
50
41
59
48
52
81
86
91
4
0.44
0.86
0.46
0.78
0.40
0.70
0.54
0.45
0.50
0.66
0.73
0.56
0.58
0.31
0.57
0.56
0.30
0.69
0.29
0.10
0.11
0.10
4-%
60
51
61
53
53
56
46
49
57
48
37
59
61
66
60
49
69
60
70
85
89
91
5
0.50
0.91
0.54
0.82
0.51
0.86
0.59
0.58
0.67
0.77
0.82
0.61
0.76
0.41
0.82
0.71
0.46
0.98
0.47
0.17
0.16
0.15
5-%
55
49
55
49
40
46
31
34
42
39
29
69
48
55
42
35
53
58
52
76
84
87
Sum%
228
158
214
171
157
177
115
145
166
150
109
239
192
216
179
142
225
208
220
321
346
357
Mean%
57.0
39.5
53.5
42.8
39.3
44.3
28.8
36.3
41.5
37.5
27.3
59.8
48.0
54.0
44.8
35.5
56.3
52.0
55.0
80.3
86.5
89.3
r-B enhancement levels 1 to 5 defined in section I.
111-25
-------
Table 8. Duncan's Multiple Range Test for Total Dry Weight differences
among UV-B irradiation enhancement levels at the Duke Univer^
sity Phytotron.
Soybean
Variety
1. Acadian
2. Americana
3. .Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Button
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelon
1. CG Fl.77-1
2. CG Fl.77-2
3. Charl. Gray
Light Level
A
A
A
A
A
A
A
A
A
A
A '
A
A
A
A
A
A
A
A
B
B
C,B
B
C
B
B
B
. B
B
B
B
B
B
B
B
B
B
B
B
B
B
C,B
B
B
B
B
C
C,B
B
B
C,B
C
D,C
C
C,D
B
B
B
C
C
D
C
C
D
C
D
C
C
B
D
C
D
C
D
C
C
B
C
C,B
C,D
C
C,B
C
B
C
C,B
C,B
B
C
C
C
C
C,B
B
B
D B,A B,C C A
B B,A B,A B A
B B,A B B A
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
111-26
-------
Table 9. Overall means for measured and computed parameters of soybean
(Glycine max) and watermelon (Citrullus vulgaris L.) varieties: LA = leaf
area, LFW = leaf fresh weight, LDW = leaf dry weight, SFW = ste:
SDW = stem dry weight, KFW = root fresh weight, ROW = root dry '
= leaf specific thickness.
Watermelon
or Soybean
Variety
Acadian
Altona
Biloxi
Bossier
Centennial
Cobb
Davis
Forres t
Hood
Button
Jupiter
Mineira
Ottotan
Pickett
Eoanoke
Santa Maria
Seminole
Hardee
CG Fl 77-1
CG Fl 77-2
Charl.Gray
LA2
107
209
183
99
184
137
102
126
136
129
131
152
95
159
119
97
174
91
22
23
23
LFW
2.1
3.9
4.0
2.0
3.3
2.7
2.3
2.6
3.1
3.3
2.6
3.2
1.9
3.3
2.9
2.0
4.2
2.3
1.0
1.1
0.9
LDW
0.31
0.58
0.56
0.31
0.50
0.39
0.33
0.41
0.46
0.49
0.40
0.47
0.29
0.49
0.41
0.29
0.59
0.33
0.09
0.09
0.08
SFW
1.5
2.7
2.7
1.3
2.2
1.9
1.4
1.7
2.0
2.0
1.8
1.8
1.2
1.7
1.7
1.5
2.1
1.1
0.6
0.5
0.5
SDW
0.17
0.36
0.31
0.17
0.31
0.22
0.15
0.22
0.23
0.23
0.22
0.23
0.14
0.21
0.19
0.17
0.23
0.12
0.02
0.02
0.02
RFW
2.0
4.5
3.7
1.5
3.3
2.4
2.2
2.2
2.8
2.4
2.3
3.1
1.3
2.6
3.1
1.2
3.4
1.6
0.3
0.3
0.3
RDW
0.11
0.26
0.21
0.10
0.22
0.16
0.14
0.15
0.20
0.18
0.17
0.21
0.09
0.20
0.19
0.08
0.24
0.10
0.02
0.02
0.02
Bio-
mass^
0.59
1.21
1.08
0.58
1.03
0.77
0.63
0.77
0.88
0.90
0.79
0.91
0.51
0.90
0.79
0.53
1.05
0.54
0.13
0.13
0.12
Root: Leaf
Shoot Density
Ratio^ :r0~~
0.52
0.45
0.37
0.34
0.44
0.41
0.44
0.38
0.42
0.37
0.39
0.44
0.31
0.45
0.45
0.29
0.40
0.29
0.20
0.23
0.25
4.01
3.37
4.14
4.73
3.52
56
09
36
4.13
4.34
34
95
20
76
36
02
3.
4.
4.
4.23
,22
,30
,60
6.00
Fresh and dry weights in grams.
2 y
Leaf area (LA) in cm .
3
Biomass = sum of leaf, stem and root dry weights.
4
Root: shoot ratio = Root dry weight divided .by shoot dry weight.
5 ' 2
Leaf specific thickness = Leaf area (cm ) divided by leaf dry weight.
111-27
-------
Table 10. Mean leaf specific thickness (leaf dry weight in grams -t- leaf area in
2 1
cm ) by UV-B enhancement regime and corresponding percent increases above
the mylar control (UV-B enhancement regime #1). Values X 10
Light Regime
-3
i
to
oo
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier -' '
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Hutton
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Sum % X %
1.8
1.9
1.9
2.1
1.7
2.0
1.8
1.8
2.0
2.4
2.7
2.4
2.2
1.9
2.2
2.3
2.1
2.3
2.4
3.3
2.4
3.1
3.4
6.0
2.6
2.4
3.4
3.3
2.8
3.5
3.4
3.0
3.7
3.1
3.3
3.3
3.4
3.5
83
26
63
62
53
30
33
89
65
17
30
42
36
95
41
43
57
48
46
4.7
3.4
4.8
4.3
4.7
3.4
3.6
4.3
3.9
4.0
4.1
4.7
3.5
4.1
3.7
4.3
3.7
4.1
5.5
161
79
153
105
176
70
100
139
95
67
52
96
59
116
68
87
76
78
129
6.4
5.0
7.6
6.3
6.7
5.9
5.4
6.0
7.5
6.6
6.3
6.3
6.2
5.8
5.9
6.3
6.0
6.0
8.1
256
163
300
200
294
195
200
233
275
175
133
162
182
205
168
174
186
161
238
4.3
4.2
5.2
5.1
4.6
3.6
4.5
5.0
5.2
4.9
4.9
5.0
4.8
5.4
4.4
5.6
5.4
5.5
6.6
139
121
174
143
171
80
150
178
160
104
81
108
118
184
100
143
157
139
175
639
389
689
510
894
375
483
639
595
363
296
408
395
600
377
448
476
426
588
159.8
97.4
172.4
127.4
223.5
93.8
121.0
159.7
148.8
90.6
74.0
102.0
98.9
150.0
94.3
112.0
119.0
106.5
147.0
Watermelons
1. CG Fl.77-1 16.4 55.9 241 .57.8 252 69.7 325 64.8 295
2. CG Fl.77-2 21.1 54.4 158 67.7 221 78.8 273 59.3 T81
.3. ' Charl. Gray 20.9 52.4 151 .78.9 278 90.0 331 58.2 178
1113 278.4
833 208.3
937 234.3
1
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 11.Duncan's Multiple Range Test for Leaf Density
differences among UV-B irradiation enhancement levels at the
Duke University Phytotron.
Soybean Light Level
Variety I 1 1 1 1
1. Acadian D. C B A B
2. Americana E D C A B
3. Altona D C B A B
4. Biloxi E D C A B
5. Bossier B A B,A A B,A
6. Centennial D C B A B
7. Cobb E D C A B
8. Davis E D C A B
9. Forrest D C C . A B
10. Hood D D C A B
11. Button D C C,B A B
12. Jupiter C C B A B
13. Mineira D D C A B
14. Otootan C B B A A
15. Pickett D C C A B
16. Roanoke D C B A A
17. Santa Maria C B B A A
18. Seminole C B B A A
19. Hardee E D C A B
Watermelon
1. CG Fl.77-1 C B B,A A B,A
2. CG Fl.77-2 D C B A C,B
3. Charl. Gray C B A A B
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
111-29
-------
2 I
Table 12. Mean leaf area (cm ) by UV-B enhancement regime and corresponding percent
reductions below the mylar control (UV-B enhancement regime //I).
M
H
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
. 7. Cobb
8. Davis
9. Forrest
10. Hood
11. Hutton
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Light Regime
Sum % X %
285
385
262
372
218
377
244
222
262
243
198
256
300
231
297
218
224
364
217
80
262
97
185
86
194
178
93
149
174
150
124
174
95
197
157
108
185
107
72
32
63
50
61
49
27
58
43
28
24
52
42
59
34
28
52
49
51
62
194
76
' 136
80
155
127
89
113
117
131
78
147
69
132
98
70
144
60
78
50
71
63
63
59
48
60
57
52
34
70
51
70
56
55
69
60
72
36
87
35
66
34
58
53
41
35
56
65
51
51
31
54
47
30
68
23
87
77
87
82
84
85
78
82
87
77
67
80
83
87
82
78
87
81
89
74
119
60
98
76
138
83
66
70
91
101
78
90
49
114
75
54
111
47
74
69
77
74
65
63
66
70
73
63
49
70
70
79
62
66
76
70
78
312
228
298
270
273
255
219
270
260
220
174
271
246
294
233
227
283
260
291
77.9
57.0
74.4
67.4
68.3
63.9
54.8
67.5
65.0
54.9
43.6
67.7
61.5
73.6
58.2
56.8
70.8
65.1
72.7
Watermelons
1. CG Fl.77-1 44
2. CG Fl.77-2 51
3. Charl. Gray 57
22
19
20
50
63
65
17
16
10
61
69
82
10
10
8
77
80
86
18 59
19 63
19 67
248 61.9
275 68.6
300 75.0
1
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 13. Duncan's Multiple Range Test for Leaf Area differences among
UV-B irradiation enhancement levels at the Duke University
Phytotron.
Soybean Light Level
Variety I 2 _3 .4. _5
1. Acadian A B B C B
2. Americana A B C E D
3. .Altona . . A B C,B D C,D
4. Biloxi A B C,B D C,D
5. Bossier A B B C B
6. Centennial A B B C C,B
7. Cobb A B C E D
8. Davis A B B D C
9. Forrest A B C E D
10. Hood A B C D C
11. Hutton A B B D C
12. Jupiter A B C C C
13. Mineira A B C E D
14. Otootan A B C D D,C
15. Pickett A B ' C D C
16. Roanoke A B C D D,C
17. Santa Maria A B C D D,C
18. Seminole A B C D C
19. Hardee A B C DC
Watermelon
1. CG Fl.77-1 A B B B B
2. CG Fl.77-2 A B B B B
3. Charl. Gray A B C C C,B
1
Light levels not follox\red by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
111-31
-------
Table 15. Duncan's Multiple Range Test for Leaf Dry Weight differences
among UV-B irradiation enhancement levels at the Duke University
Phytotron.
Soybean
Variety
1. Acadian
2. Americana
3. .Altona
4. Biloxi
5. Bossier
6. Centennia.l
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Hutton
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
.18. Seminole
19. Hardee
Watermelon
1. CG Fl.77-1
2. CG Fl.77-2
3. Charl. Gray
Light Level
JL
A
A
A
A
B,A
A
A
. A
A
A
A
A
A
A .
A
A
A
A
A
2
C,B
B
C,B
B
B,C
B
A
B
A
B
A
B
B
B
B
A
B
B
B
1
B
B,A
B
B
A
B
A
A
B
B
A
C,B
B
C
C
B
C
B
C,B
i
C
C
C
C
C
C
C
C
C
C
B
C
D
D
D
C
D
C
D
_5
B
C
'C,B
C,B
B,A,C
B
B
B
B
C,B
A
C,B
C
C
C
B
C,B
B
C
C A B,A B A
C B,A A B,C A
B B,A B B A
IT--
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
111-33
-------
Table 16 . Mean stem dry weight (in grams at 60 C) by UV-B enhancement regime
H
H
H
US
-O
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Hutton
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
1. CG Fl.77-1
2. CG Fl.77-2
. 3. Charl. Gray
and corresponding percent reductions [(-) or increases (+) in watermelons]
below the mylar control (UV-B enhancement regime //I).
.19
.17
.25
Light Regime
.27 +42
.21 +24
.21 -16
.25 +32
.19 +12
.12 -52
,16 -16
15 -12
,17 -32
.35 +84
.30 +76
.21 -16
Sum % X %
.41
.66
.50
.53
.33
.56
.36
.28
.41
.40
.38
.49
.48
.31
.42
.35
.35
.48
.28
.09
.38
.15
.33
.12
.32
.23
.13
.22
.23
.23
.21
.23
.14
.25
.24
.16
.21
.10
78
42
70
38
64
43
36
54
46
43
39
57
52
55
40
31
54
56
64
.11
.30
.17
.29
.18
.26
.21
.15
.16
.18
.20
.12
.17
.08
.12
.13
.11
.15
.08
73
55
66
45
45
54
42
46
61
55
47
76
65
74
71
63
69
69
71
.12
.23
.11
.20
.09
.18
.13
.09
.12
.14
.16
.13
.11
.06
.10
.10
.07
.12
.04
71
65
78
62
73
68
64
68
71
65
58
73
77
81
76
71
80
75
86
.12
.25
.14
.22
.13
.24
.17
.13
.18
.18
.19
.16
.17
.10
.17
.14
.13
.19
.08
51
62
72
58
61
57
53
54
56
55
50
67
65
68
60
60
63
60
71
273
224
286
204
242
221
195
221
234
218
194
273
258
277
248
226
266
260
292
62.3
56.1
71.5
50.9
60.6
55.4
48.8
55.4
58.5
54.4
48.5
68.3
64.6
69.4
61.9
56.4
66.5
65.1
73.0
+142 +35.5
+100 +25.0
116 29.0
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 17. Duncan's Multiple Range Test for Stem Dry Weight differences
-among UV-B irradiation enhancement levels at the Duke University
Phytotron.
Soybean Light Level
Variety I 1 1 A 1
1. Acadian A B B B B
2. Americana A B C C C
3. Altona A C,B B C C,B
4. Biloxi A B B C C
5. Bossier A D,C B D C
6. Centennial A B C D C
7. Cobb A B B D C
8. Davis A B B C B
9. Forrest A B C,D D C,B
10. Hood A B D,C D C
11. Button A B C,B D C,D
12. Jupiter A B C C C,B
13. Mineira A B CD C
14. Otootan A B D,C D C
15. Pickett A B D D C
16. Roanoke A B C C C
17. Santa Maria A B C D C,B
18. Seminole A B C,D D C,B
19. Hardee A B B C B
Watermelon
1. CG Fl.77-1 D,C B,A B,C D A
2. CG Fl.77-2 B B B B A
3. Charl. Gray A B,A C B,C B,A
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
111-35
-------
Table 18. Mean root dry weight (in grams at 60 C) by UV-B enhancement regime
M
M
H
UJ
ON
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Hutton
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
1. CG Fl.77-1
2. CG Fl.77-2
3. Charl. Gray
and corresponding percent reductions [(-) or increases (+) in watermelons]
below the mylar control (UV-B enhancement regime #1).
Light Regime
1 2 % 3 % 4 % 5 % Sum % X %
.17
.37
.19
.35
.16
.36
.20
.20
.22
.27
.22
-.34
.35
.16
.33
.25
.16
.41
.18
.10
.31'
.14
.24
.09
.23
.16
.13
.18
.20
.16
.13
.17
.10
.21
.20
.06
.19
.07
41
16
26
31
44
36
20
35
18
26
27
62
51
38
36
20
63
54
61
.12
.25
.11
.18
.12
.18
.14
.14
.10
.19
.19
.10
.16
.06
.12
.14
.05
.18
.07
29
32
42
49
25
50
30
30
55
30
14
71
54
63
64
44
69
56
61
.10
.20
.09
.17
.08
.17
.13
.12
.12
.16
.17
.13
.16
.06
.15
.16
.06
.17
.06
41
46
53
51
50
53
35
40
45
41
23
62
54
63
55
36
63
59
67
.08
.17
.10
.13
.08
.17
.15
.14
.14
.16
.15
.12
.19
.06
.17
,18
.06
.24
.10
53
54
47
63
50
53
25
30
36
41
32
65
46
63
48
28
63
41
44
164
149
163
194
169
192
110
135
155
137
96
260
206
225
203
128
258
210
233
41.0
37.2
42.1
48.6
' 42.2
47.9
27.5
33.8
38.6
34.3
24.0
65.0
51.4
56.3
50.8
32.0
64.5
52.4
58.3
.10
.20
.13
.13 +30
.12 -40
.20 +54
.18 +80
19 -5
, 16 +23
.19 +90
.22 +10
.25 +92
+260 +65.0
-60 -15.0
+154 +38.5
1
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 19.Duncan's Multiple Range Test for Root Dry Weight differences
among UV-B irradiation enhancement levels at the Duke University
Phytotron.1
Soybean Light Level
Variety I ฃ 1 A I
1. Acadian A C,B B C,B C
2. Americana A B C D,C D
3. Altona A B B B B
4. Biloxi A B C,B C,B C
5. Bossier A C,B B C,B C
6. Centennial A B B B B
7. Cobb A B C,B. C C,B
8. Davis A B B B B
9. Forrest A B,A C C B,C
10. Hood A B,A B,A B B
11. Hutton A B B,A B B
12. Jupiter A B B B B
13. Mineira A B B B B
14. Otootan A B C C C
15. Pickett A B C C,B C,B
16. Roanoke A B,A B B B
17. Santa Maria A B B B B
18. Seminole A C C C B
19. Hardee A C C C B
Watermelon
1. CG Fl.77-1 C B,C B,A A A
2. CG Fl.77-2 B,A B B,A B,A A
3. Charl. Gray B,C B,A C B,C A
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
Ill-37
-------
Table 20. Mean biomass per pot for mylar control and 4 UV-B enhancement treatments and biomass partitioning.
Mean biomass per pot for Mylar
control (M) and all UV-B treatments
Biomass Partitioning in Percent
H
U)
CO
Variety
Soybean
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Acadian
Americana
Altona
Biloxi
Bossier
Centennial
Cobb
Davis
Forrest
Hood
Hut ton
Jupiter
Mineira
Otootan
Pickett
Roanoke
Santa Maria
Seminole
Hardee
Leaves
M
0.53
0.74
0.51
0.77
0.36
0.67
0.43
0.40
0.53
0.59
0.54
0.63
0.65
0.44
0.67
0.50
0.46
0.83
0.51
UV-B
0.27
0.55
0.30
0.51
0.30
0.45
0.39
0.31
0.38
0.43
0.48
0.35
0.43
0.25
0.46
0.39
0.25
0.52
0.29
Stems
M
0.41
0.66
0.50
0.53
0.33
0.56
0.36
0.28
0.41
0.40
0.38
0.49
0.48
0.31
0.42
0.35
0.35
0.48
0.28
UV-B
.11
.17
.13
.13
.08
.14
.09
.07
.10
.10
.10
.12
.12
.08
.11
.09
.09
.12
.07
Roots
M
0.17
0.37
0.19
0.35
0.16
0.36
0.20
0.20
0.22
0.27
0.22
0.34
0.35
0.16
0.33
0.25
0.16
0.41
0.18
UV-B
.10
.23
.11
.18
.09
.19
.15
.13
.14
.18
.17
.12
.17
.07
.16
.17
.06
.20
.08
Biomass
M
1.11
1.77
1.20
1.65
0.85
1.59
0.99
0.88
1.16
1.26
1.14
1.46
1.48
0.91
1.42
1.10
0.97
1.72
0.97
UV-B
0.48
1.07
0.55
0.95
0.52
0.89
0.72
0.57
0.68
0.79
0.84
0.62
0.77
0.41
0.78
0.72
0.43
0.89
0.44
Leaves
M
48
42
43
47
42
42
43
45
46
47
47
43
44
48
47
45
47
47
53
UV-B
56
52
54
54
57
51
54
55
55
54
57
56
57
60
59
54
59
59
66
Stems
M
37
37
42
32
39
35
36
32
35
32
33
34
32
34
30
32
36
28
29
UV-B
23
27
26
27
25
28
26
22
25
23
23
25
22
23
20
21
28
19
17
Roots
M
15
21
16
21
19
23
20
23
19
32
19
23
24
18
23
23
16
24
19
UV-B
21
22
20
19
18
21
20
23
20
23
20
19
22
17
21
24
14
22
17
Watermelon
1.
2.
3.
CGF1.77-1
CGF1.77-2
Charl. Gray
0.42
0.65
0.77
0.95
0.96
0.85
0.19
0.17
0.25
0.25
0.21
0.18
0.10
0.20
0.13
.17
.17
.18
0.71
1.02
1.15
1.37
1.35
1.21
59
64
67
69
72
70
27
17
22
19
16.
15
14
20
11
12
13
15
-------
Table 21.
M
I
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Button
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
1. CG Fl.77-1
2. CG Fl.77-2
3. Charl. Gray
Biomass partitioning for % leaves by UV-B enhancement regime and corresponding
percent increase above the mylar control (UV-B enhancement regime #1).
Light Regime
1 2 % 3 % 4 % 5 % Sum % X %
47
42
42
47
42
42
43
46
46
47
46
43
44
49
47
46 .
47
48
53
58
48
51
51
60
48
52
55
55
55
57
55.
57
58
56
53
59
60
67
23
14
21
9
43
14
21
20
20
17
24
28
30
18
19
15
26
25 .
26
57
55
56
54
55
54
56
57
61
56
57
60
59
63
66
59
59
62
69
21
31
33
15
31
29
30
24
33
19
24
40
34
29
40
28
26
29
30
50
50
56
53
58
49
53
54
53
55
56
55
54
60
56
53
61
58
. 66
6
19
33
13
38
17
23
17
15
17
22
28
23
22
19
15
30
21
25
59
53
55
57
59
53
54
54
52
55
58
55
53
60
58
54
59
56
61
26
26
31 .
21
40
26
26
17
13
17
26
28
20
. 22
23
17
26
17 .
+ 15
76
90
119
57
152
86
100
78
80
70
96
124
107
92
102
76
108
92
96
19.0
22.6
29.8
14.4
38.1
21.4
25.0
19.6
20.1
17.6
24.0
31.0
26.7
23.0
25.5
19.0
27.0
22.9
24.0
58
63
64
72
75
68
24
19
6
66 14
67 6
66 3
68 17
68 8
67 5
71
52
34
17.7
13.1
8.6
1
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table22. Duncan's Multiple Range Test for Percent Leaf differences
among UV-B irradiation enhancement levels at the Duke University
Phytotron.
Soybean
Variety !_
1. Acadian B
2. Americana D
3. Altona C
A. Biloxi D
5. Bossier C
6. Centennial C
7. Cobb B
8. Davis B
9. Forrest C
10. Hood B
11. Hutton B
12. Jupiter C
13. Mineira C
14. Otootan B
15. Pickett C
16. Roanoke C
17. Santa Maria B
18. Seminole D
19. Hardee C
Watermelon
1. CG Fl.77-1 B
2. CG Fl.77-2 B
3. Charl. Gray B
Light Level
2^
A
C
B
C
A
B
A
A
B
A
A
B
A
A
B
B
A
B,A
A
^
A
A
B,A
B
B
A
A
A
A
A
A
A
A
A
A
A
A
A
A
_4
B
B,C
A
C,B
B,A
B
A
A
B
A
A
B
B
A
B
B
A
B,C
A
J5
A
B,A
B,A
A
A
A
A
A
B
A
A
B
B
A
B
B
A
C
B
A
A
B
A
A
A
A
B
B
A
B
B
Light levels.not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
111-40
-------
Table 23.
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Button
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
1. CG Fl.77-1
2. CG Fl.77-2
3. Charl. Gray
Biomass partitioning for % stems by UV-B enhancement
regime and corresponding percent reductions below
the mylar control (UV-B enhancement regime #1).
Light Regime
Sum % X%
1_
37
37
42
33
40
35
36
32
36
32
34
34
33
35
31
32
37
28
29
28
18
23
2_
21
29
26
29
23
30
28
23
25
26
26
27
25
24
24
26
30
21
20
19
16
17
%_
43
22
38
12
43
14
22
28
31
19
24
21
24
31
23
19
19
25
31
32
11
26
3_
21
25
27
28
28
27
26
22
23
22
23
22
21
21
17
20
28
17
16
21
14
12
%_
43
32
36
15
30
23
28
31
36
31
32
35
36
40
45
38
24
39
45
25
22
48
4_
27
26
24
26
21
27
24
20
23
21
21
22
18
20
19
19
21
17
13
16
14
17
%_
27
30
43
21
48
23
33
38
36
34
38
35
45
43
39
41
43
39
55
43
22 '
26
_5_
25
28
27
26
26
28
24
22
27
24
23
. 26
23
24
21
20
28
19
18
20
18
14
%_
32
24
35
21
35
20
33
31
25
25
32
24
30
31
32
38
24
32
38
29
0
39
145
103
153
69
155
80
116
128
128
109
126
115
136
146
139
134
110
136
169
36.3
27.0
33.3
17.3
38.8
20.0
29.0
32.0
31.9
27.3
31.5
28.8
34.1
36.4
34.7
33.6
27.5
33.9
42.3
129 32.1
56 13.9
139 34.8
UV-B enhancement levels 1 to 5 are defined in section I.
111-41
-------
Table 24.Duncan's Multiple Range Test for Percent Stem differences
among ITV-B irradiation enhancement levels at the Duke Univer-
sity Phytotron.
Soybean
Variety
1. Acadian
2. .Americana
3. Altcna
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Button
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelon
1. CG Fl.77-1-
2. CG Fl.77-2
3. Charl. Gray
Light Level
I
A
A
A
A,
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
_2
C
B
C,B
B
C,D
B
B
B
B
B
B
B
B
B
B
B
B
B
B
1
C
C
B
B
B
C,B
C,B
B
B
C
C,B
C
C
B
D
C
B
C
C
4_
B
C,B
C
C
D
C
C
B
B
C
C
C
D
B
D
C
C
C
D
A
A
A
B
A
B
B
A
C
B
A
B
C,B
B
C,B
C,B
C,B
C,B
C
B
B
C,B
C,B
B
C
B
C
C
B
C
C,B
B
A
C,B
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section 1. Only horizontal comparisons are valid.
111-42
-------
Table 25.
H
M
M
I
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Hutton
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
Biomass partitioning for % root by UV-B enhancement regime and corresponding
percent reductions below the mylar .control (UV-B enhancement regime #1).
Light Regime
1 2% 3 % 4 % 5% Sum % "X %
15
21
16
20
18
22
20
22
18
21
20
23
23
.17
22
21
16
24
18
22
23
23
20
17
22
20
22
20
20
17
18
18
18
20
21
11
19
13
+47
+10
+44
0
-6
0
0
0
+11
-5
-15
-22
-22
+6
9
0
-31
-21
-28
22
20
17
17
17
19
18
21
. 15
22
20
18
20
16
17
21
13
20
15
+47
-5
+6
-15
-6
-14
-10
+5
-17
+5
0
-22
-13
-6
-23
0
-19
-17
-17
22
23
19
21
21
24
23
26
24
24
23
23
28
20
25
28
18
24
21
+47
+10
+19
+5
+17
+9
+15
-18
+33
+14
+15
0
+22
+18
+14
+33
+13
0
+17
16
19
18
16
15
19
22
24
21
21
19
19
24
15
20
26
13
25
21
+7
-10
+13 .
-20
-17
-14
+ 10
-9
+17 '
0
-5
-17
+4
-12
-9
+24 ;
-19
+4
+ 17
+148
+5
+81
-30
-11
-18 :
+15
-23
+44
+14
-5
-61
-9
+6
-27
+57
-56
-33
-11
37.0
+1.2
+20.3
-7.5
-2.8
-4.5
3.7
-5.7
+11.1
+3.6
-1.3
15.3
+2.2
+1.5
-6.8
+14.3
-14.0
-8.3
-2.8
1. CG Fl.77-1
2. CG Fl.77-2
3. Charl. Gray
15
19
13
9
9
15
-40
-53
+15
13
11
12
-13
-42
-8
18
18
17
+20
-5
+31
12
14
19
-20
-26
+46
-53
-126
+85
-13.3
-31.6
+21.2
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 26. Duncan's Multiple Range Test for Percent Root differences
among UV-B irradiation enhancement levels at the Duke Univer-
1
sity Phytotron.
Soybean Light Level
Variety _1 _2 1 A 5.
1. Acadian B A A A B
2. Americana B,A A B A B
3. Altona BAB B,A B,A
4. Biloxi A A B A B
5. Bossier B,A B,C B,C A C
6. Centennial A B,A B A B
7. Cobb B,A,C B,C C A B,A
8. Davis B,A B,A B A B,A
9. Forrest B,C B C A B,A
10. Hood A A A A A
11. Button B B B A B
12. Jupiter A B B A B,A
13. Mineira B C C A B
14. Otootan B,A B,A BAB
15. Pickett B,A B,C C A B,C
16. Roanoke B B B A ^A
17. Santa Maria B,A C B,C A B,C
18. Seminole A B B A A
19. Hardee B,A C B,C A A
Watermelon
1. CG Fl.77-1 B,A C B,C A B,C
2. CG Fl.77-2 ABBA B,A
3. Charl. Gray B,A B,A B B,A A
1
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
111-44
-------
M
I
Table 27. Mean root:shoot ratios by UV-B enhancement regime and corresponding
increases (+) or decreases (-) relative to the mylar control (UV-B
enhancement regime //I)..
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Button
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
Light Regime
1.
2.
3.
CG Fl.
CG Fl.
Charl.
77-1
77-2
Gray
.18
.28
.15
.10
.10
.19
-44
-64
+27
.15
.13
. .13
-17
-54
-13
.22
.23
.21
+22
-18
+40
.14
.16
.25
-22
-43
+67
Sum % X %
.18
.27
.19
.26
.23
.29
.26
.29
.23
.27
.25 .
. .30
.31
.21
.29
.27
.19
.31
.22
.28
.31
.35
.26
.21
.28
.25
.29
.25
.25
.21
.22
.23
.22
.25
.28
.12
.23
.16
+56
+15
+84
0
-9 .
-3
-4
0
+9
-7
-16
-27
-26
+5
-14
+4
-16
-26
-27
.29
.26
.21
.21
.21
.24
.22
.27
.18
.30
.26
.22
.25
.19
.21
.27
. .15
.26
.18
+61
-4
+11
-19
-9
'-17
-15
-7
-22
+11
0
-27
-19
-10
-28
0
-21
-16
-18
.31
.31
.25
.27
.27
.32
.30
.35
' .31
.32
.30
.29
.39
.25
.35
.41
.22
.33
.28
+72
+15
+32
+4 .
+17
+10
+15
+21
+35
+19
+20
-3
+26
+19
+21
+52
+16
+6
+27
.19
.24
.22
.20
.18
.24
.29
.32
.27
.28
.23
.24
.33
.18
.26
.35
.15
.33
.27
+6
-11
+ 16
-23
-22
-17
+11
+10
+17
+4
-8
-20
+6
-14
-10
+30 .
-21
+6
+23
195
+15
+142
-38
-22
-28
+7
+24
+39
+26
-4
77
-13
0
-31
+85
-42
-29
+5
+48.0
+3.7
+35.5
-9.6
-5.4
-6.9
+1.8
+6.0
+9.8
+6.5
-1.0
-19.3
-3.2
0
-7.8
+21.3
-10.5
-7.3
+1.3
-61 -15.3
-179 -44.6
+120 +30.0
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 28. Duncan's Multiple Range Test for RootrShoot Ratio differences
among UV-B irradiation enhancement levels at the Duke University
Phytotron.
Soybean Light Level
Variety 11111
1. Acadian C B,A,C B,A A B,C
2. Americana B,A A B A B
3. Altona BAB B,A B,A
4. Biloxi A A B A B
5. Bossier B,A B,C B,C A C
6. Centennial A B,A B A B
7. Cobb B,A,C B,C C A B,A
8. Davis B,A B,A B .A B,A
9. Forrest B,C B C A B,A
10. Hood A A A A A
11. Button B,A B B,A A B
12. Jupiter A B B A B
13. Mineira B C C A B
14. Otootan B,A B,A 'B A B
15. Pickett B,A B,C C A B,C
16. Roanoke B B B A A
17. Santa Maria B,A C B,C A B,C
18. Seminole A B B A A
19. Hardee B,A C B,C A A
Watermelon
1. CG Fl.77-1 B,A C B,C A B,C
2. CG Fl.77-2 A B B B,A B,A
3. Charl. Gray A A A A A
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid.
111-46
-------
Table 29 . Mean chlorosis rating (0-9) by UV-B enhancement regime
Light Regime
1
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Variety
Soybeans
Acadian
Americana
Altona
Biloxi
.Bossier
Centennial
Cobb
Davis
Forrest
Hood
Button
Jupiter
Mineira
Otootan
Pickett
Roanoke
Santa Maria
Seminole
Hardee
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
8.0
2.5
7.1
6.1
5.0
4.4
3.4
4.0
5.0
3.2
3.1
3.4
3.1
4.8
3.7
3.3
4.5
- 4.7
4.4
3
8.9
5.8
8.9
7.2
4.9
3.9
3.4
4.4
4.4
3.2
3.2
4.9
3.4
6.0
3.1
4.0
4.7
6.2
6.3
4
8.3
6.6
8.7
8.5
7.1
7.4
7.2
6.8
7.7
6.2
5.8
6.0
6.4
9.0
6.3
7.5
8.8
8.3
8.6
5
8.6
6.9
8.9
8.5
6.4
6.9
7.4
7.3
8.3
6.9
6.1
7.4
6.7
9.0
5.9
7.8
7.7
7.9
8.3
Sum %
33.8
21.8
33.6
30.3
23.4
22.6
21.4
22.5
25.4
19.5
18.1
21.7
19.6
28.8
19.0
22.6
25.7
27.1
27.6
X %
8.5
5.5
8.4
7.6
5.9
5.7
5.4
5.6
6.4
4.9
4.5
5.4
4.9
7.2
4.8
5.7
6.4
6.8
6.9
Watermelons
1. CG Fl.77-1 0 5.1
2. CG Fl.77-2 0 4.4
3. Charl. Gray 0 4.6
7.8
6.3
6.4
27.2
24.8
25.2
6.8
6.2
6.3
UV-B enhancement levels 1 to 5 are defined in section I.
111-47
-------
Table 30. Duncan's Multiple Range Test for-Chlorosis differences among
UV-B irradiation enhancement levels at the Duke University
Phytotron.
Soybean Light Level
Variety 1 1 1 1 A
1. Acadian D C A B,C B,A
2. Americana C B A A A
3. Altona C B A A A
4. Biloxi D C B A A
5. Bossier C B B A B,A
6. Centennial C B B A A
7. Cobb C B B A A
8. Davis C B B A A
9. Forrest C B B A A
10. Hood C B B A A
11. Hutton C B B A A
12. Jupiter E D C B A
13. Mineira C B B A A
14. Otootan D C B A A
15. Pickett C B B A A
16. Roanoke C B B A A
17. Santa Maria C B B A A
18. Seminole D C B A A
19. Hardee D C B A A
Watermelon
1. CG Fl.77-1 C B A A A
2. CG Fl.77-2 C B A A B
3. Char1. Gray C B A A B
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined
in Section I. Only horizontal comparisons are valid.
111-48
-------
Table 31.
H
H
M
.f>
VD
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Hutton
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
1. CG Fl.77-1
2. CG Fl.77-2
3. Charl. Gray
Mean height (iron) after 2 weeks by UV-B enhancement regime and corresponding
percent reductions below the mylar control (UV-B enhancement regime #1).
Light Regime
1 2 % 3 % 4 % 5 % Sum % X %
134
178
183
156
99
151
121
96
126
127
128
134
151
87
90
107
105
95
79
121
153
141
156
89
140
99
85
111
115
112
121
108
88
97
97
107
98
72.
10
14
23
0
10
7
18
11
12
9
13
10
28
+1
+8
9
+2
+3
9
116
134
134
141
95
128
94
85
105
96
99
105
101
75
76
83
90
90
71
13
25
27
10
4
15
22
11
17
24
23
22
33
14
16
22
14
5
10
108
122
111
129
77
113
82
72
92
89
93
104
90
75
69
77
81
81
56
19
31
39
17
22
25
32
25
27
30
27
22
40
14
23
28
23
15
29
115
119
121
113
82
117
83
75
102
98
94
103
96
74
73
. 79
91
75
61
14
33
34
28
17
23
31
22
19
23
27
23
36
15
19
26
13
21
23
56
103
123
54
54
70
103
70
75
87
95
77
138
41
50
86
48
38
71
14.0
25.8
30.7
13.6
13.4
' 17.5
25.8
17.4
18.7
21.7
22.5
19.3
34.6
10.3
12.5
21.5
12.0
9.5
17.8
31
26
24
25
21
21
19
19
13
23
18
17
26
31
29
26
21
19
16
19
21
84
100
88
21.0
25.0
21.9
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 32.Duncan's Multiple Range Test for Height 2 differences among
UV-B irradiation enhancement levels at the Duke University
Phytotron.
Soybean Light Level
Variety 1 1 1 4. 1
1. Acadian A B C,B C C,B
2. Americana A B C D D
3. Altona . A B B C C
4. Biloxi A A B C D
5. Bossier A B,A,C B,A C B,C
6. Centennial A A B C C,B
7. Cobb A B B C C
8. Davis A B B C C,B
9. Forrest A B B C C,B
.10. Hood A B C C C
11. Hutton A B C C C
12. Jupiter A B C C C
13. Mineira A B C,B D C,D
14. Otootan A A B B B
15. Pickett A A B B B.
16. Roanoke A B C C C
17. Santa Maria A A B B .B
18. Seminole A A B,A B,C C
19. Hardee A A A B B
Watermelon
1. CG Fl.77-1 A A A A A
2. CG Fl.77-2 A B B B B
3. Charl. Gray A B C,B C C,B
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid. Height 2 is
two weeks after planting.
111-50
-------
H
H
H
I
Table 33. Mean height (mm) after 3 weeks by UV-B enhancement regime and corresponding
percent reductions below the mylar control (UV-B enhancement regime //I).
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Button
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
Light Regime
Sum % X
262
301
374
270
229
258 .
257
186
242
211
204
248
270
.189
185
187
204
172
142
158
224
206
216
131
205
166
130
166
165
163
182
152
128
148
142
158
137
102
40
26
45
20
43
21
35 .
30
31
22
20
27
44
32
20
24
23
20
28
137
177
173
196
125
177
142
119
140
131
139
148
132
100
110
117
133
124
86
48
41
54
27
45
31
45
36
42
38
32
40
51
47
41
37
35
28
39
127
158
141
179
102
143
111
102
114
120
132
137
113
99
94
100
121
110
74
52
48
62
34
55
45
57
45
53
43
35
45
58
48
49
47
41
36
48
141
160
160
170
116
164
124
109
139
134
135
149
124
102
110
108
132
105
77
46
47
57
37
49
36
52
41
43
36
34
40
54
46
41
42
35
39
46
186
161
218
118
193
133
189
153
169
139
121
152
207
173
150
150
134
123
161
46.5
40.3
-54.5
29.5
48.3
33.2
47.3
38.2
42.3
34.8
30.3
38.0
51.8
43.3
37.6
37.6
33.5
30.8
40.3
1.
2.
3.
CG Fl.77-1
CG Fl.77-2 .
Charl. Gray
50
39
39
27
21
20
46
46
49
. 24
16
19
52
59
51
22
18-
19
56
54
51
26
20
19
48
49
51
202
208
203
50.5
51.9
50.6
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 34.Duncan's Multiple Range Test for Height 3 differences among
UV-B irradiation enhancement levels at the Duke University
Phytotron.
Soybean Light Level
Variety 1 A 1 A 1
1. Acadian A B C. C C
2. Americana A B C C C
3. Altona A B C D C
4. Biloxi A B C D D
5. Bossier A B B C C,B
6. Centennial A B C D C
7. Cobb A B C E D
8. Davis A B C,B D C,D
9. Forrest A B C D C
10. Hood A B C C C
11. Button A B C C C
12. Jupiter A B C C C
13. Mineira A B C D D,C
14. Otootan A B C C C
15. Pickett A B C C C
16. Roanoke A B C D D,C
17. Santa Maria A B C C C
18. Seminole A B C D D
19. Hardee A B C,B C C
Watermelon
1. CG Fl.77-1 A B B B B
2. CG Fl.77-2 A B B B B
3. Charl. Gray A B B B B
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid. Height 3 is
three weeks after planting.
111-52
-------
Table 35
I
Ln
CJ
Variety
Soybeans
1. Acadian
2. Americana
3. Altona
4. Biloxi
5. Bossier
6. Centennial
7. Cobb
8. Davis
9. Forrest
10. Hood
11. Hutton
12. Jupiter
13. Mineira
14. Otootan
15. Pickett
16. Roanoke
17. Santa Maria
18. Seminole
19. Hardee
Watermelons
Mean height (mm) after 4 weeks by UV-B enhancement regime and corresponding
percent reductions below the mylar control (UV-B enhancement regime //I).
Light Regime
1 2% 3% 4% 5% Sum % X %
376
406
495
380
330
373
357
282
379
299
302
353
415
340
293
287
327
276
237
171
256
221
247
148
249
214
162
207
210
204
262
193
165
185
193
181
168
119
55
37
55
35
55
33
40
43
45
30
32
26
53
51
37
33
45
39
50
146
208
187
227
144
219
186
144
165
169
174
171
163
120
129
142
154 .
145
91
61
49
62
40
56
41
48
49
56
43
42
52
61
65
56
51
53
47
62
134
184
149
211
111
153
127
113
122
141
146
149
126
110
104
117
135
130
84
64
55
70
44
66
59
64
60
68
53
52
58
70
68
65
59
59
53
65
159
190
176
199
134
202
158
168
171
168
168
172
148
121
141
133
152
132
87
58
53
64
48
59
46
56
40
55
44
44
51
64
64
52
54
54
52
63
238
194
252
167
237
179
208
192
225
170
170
187
248
248
209
196
211
192
240
59.5
48.4
63.0
41.8
59.3
44.8
52.0
48.0
56.1
42.5
42.5
46.8
62.0
62.1
52.3
49.0
52.8
47.9
60.0
1.
2.
3.
CG Fl.77-1
CG Fl.77-2
Charl. Gray
62
56
59
34
25
27
45
55
54
28
21
20
55
63
66
23
19 '
18
63
66
69
32
24
24
48
57
59
211
241
249
52.8
60.3
62.3
1
UV-B enhancement levels 1 to 5 are defined in section I.
-------
Table 36.Duncan's Multiple Range Test for Height 4 differences among
UV-B irradiation enhancement levels at the Duke University
1
Phytotron.
Soybean Light Level
Variety 11111
1. Acadian A B C,D D C,B
2. Americana A 8 C C C
3. Altona A B C D C
4. Biloxi A B C D D
5. Bossier A B B C B
6. Centennial A B C D C
7. Cobb A B C E D
8. Davis A B C,B C B
9. Forrest A B C DC
10. Hood A B C D C
11. Button A B C D C
12. Jupiter A B C C C
13. Mineira A B C D C
14. Otootan A B C C C
15. Pickett A B C D C
16. Roanoke A B C D D,C
17. Santa Maria A B C C C
18. Seminole A B C C C
19. Hardee A B C C C
Watermelon
1. CG Fl.77-1 A B B B B
2. CG Fl.77-2 A B B B B
3. Charl. Gray A B C,B C C,B
Light levels not followed by the same letter are significantly
different (.05 level). UV-B enhancement irradiances are defined in
Section I. Only horizontal comparisons are valid. Height 4 is
four weeks after planting.
111-54
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EFFECTS OF ULTRAVIOLET-B. RADIATION ENHANCEMENTS UNDER
FIELD CONDITIONS ON POTATOES, TOMATOES, CORN, RICE,
' SOUTHERN PEAS, PEANUTS, SQUASH, MUSTARD AND RADISH
Abstract
Nine crops were grown to maturity in the field under a UV-B gradient
irradiator using Westinghouse FS-40 sun lamps equipped with cellulose
acetate filters. UV-B levels ranged from 0.10 to 0.84 for corn, potatoes
and tomatoes, 0.10 to 1.55 for peanuts, peas and rice and 0.18 to 3.1 for
squash, mustard and radish. Fruit quality and quantity, leaf area, total
biomass and biomass partitioning, root:shoot ratios and leaf density were
all affected by enhanced UV-B radiation. Most of these affects can probably
be accounted for by reduction in net carbon exchange, leaf expansion and
phloem translocation.
Yield was consistently reduced at the highest UV-B enhancement levels
for all crops with lower levels of UV-B approaching or equa&ng control yields.
Treated plants had fewer large fruit (i.e. tomatoes, number of large peanuts
and potatoes). In most cases, fewer fruit of a smaller size were harvested.
However, in the case of corn, despite reductions in vegetative growth and
the number of tillers and silk length in corn, the percent fill and weight
of the ears of corn was not statistically reduced. Significant reductions
*
in the number and total weight of Southern peas were also found.
Biomass accumulations were similar except increases were noted for
IV-1
-------
radishes, and potato biomass was similar to the controls. Biomass
partitioning was altered, especially in mature plants where a larger per-
.cent of the dry matter was found in the leaves with reductions in stems and
roots. This also tended to reduce root:shoot ratios. Reductions in biomass
were found even at the time of thinning but these were overall reductions
with root reductions becoming more pronounced with age.
Flowering was delayed in UV-B treated plants. Flower counts were
higher and earlier in tomatoes. The number of fruit was higher in control
squash plants at the early harvest date indicating either flowering was
delayed in the treated plants or the treated squash were not setting fruit.
Spike weight was reduced and maturity was delayed in rice. This seems to
have been due to delayed growth during bolting.
IV- 2
-------
The purpose of the present study was to evaluate the main effects and
interactions of 4 flux levels of UV-B radiation on soybeans xvith simultaneous
exposure to 4 flux levels of longer wavelength light. More specifically, the
objectives were 1) to determine if UV-B radiation in lower fluxes was
affecting net carbon exchange, transpiration, dark respiration and the
associated diffusive resistances; 2) to test if these UV-B fluxes were
effective over a range of PAR and if photorepair is complete at high ir-
radiances; and 3) to examine the validity of extrapolating from low PAR
irradiance experiment in greenhouses or growth chambers to field or natural
situations.
Materials and Methods
Plant Materials and Growth Conditions
'Hardee' soybeans (Glycine max), supplied by the Florida State Seed Labora-
tory, and 'Jori1 wheat (Triticum aestivum) were grown from seed in the con-
trolled environment facilities of the Southern Plant Environment Laboratories
3
located at Duke University. Seeds were sown into 250 cm of a 1:1 mixture of
.course sand and vermiculite (v:v). These were watered with dionized water
and placed into a phytotron greenhouse with a 26/20ฐC day-night temperature
regime. Natural daylight was extended to 16 hours by incandescant floodlamps.
Soon after germination, the soybeans were thinned to uniformity to 2 per pot
and the wheat to 4 per pot. During the first few weeks, the pots were watered
to excess twice daily with dionized water. Thereafter, all plants were
watered three times daily, with 1/2 strength modified Hoagland's solution in
the mornings, followed by dionized water in the afternoons and evenings.
Nine replicate containers \jere grown under each of 16 UV-B and PAR treat-
V-3.
-------
V. Introduction
Many species of economically important crop plants exhibit reductions in
growth and net carbon exchange following exposure to UV-B irradiances (Brandle
ฃt _a_l., 1977; Van _et al_., 1976; Bartholic _et al., 1975; Biggs et_ juL., 1975).
However, the mode of action of UV-B radiation on biological systems is not
clearly understood. Much of this is a reflection of the wide range of treat-
ment and experimental conditions used by different investigators. Earlier
workers used germicidal lamps as a UV irradiance source, which are essentially
line source emitters at 253.7 nm (UV-C region). Since ultraviolet radiation
below 295 nm is effectively absorbed before reaching the earth's surface, the
conclusions of these earlier investigations must be viewed with caution.
Studies using polychromatic UV-B emitters (such as filtered Westinghouse
FS 40 sunlamps) have generally employed UV-B irradiances approximately equi-
valent to 35 to 50% ozone depletions (Van ^t al., 1976; Sisson and Caldwell,
1976; Ambler et^ a^., 1975). Only a few studies have examined UV-B enhancement
and ozone depletions below this level.
Photoreactivation has been shown to be an effective mechanism in the
repair of UV-B induced damage in micro-organisms and algae. This repair
requires simultaneous or subsequent exposure to radiation of longer wave-
lengths (315-550 nm). There is evidence suggesting that UV-B associated
decreases in net carbon exchange are photoreactible (Van et^ al^., 1976; Sisson
and Caldwell, 1976). However, these studies incorporated low PAR irradiances,
combined with large UV-B fluxes.
Abbreviations: UV-B = Ultraviolet light between 280-320 nm; PAR = Photo-
synthetically Active Radiation (between 400-700 nm).
V-2
-------
EFFECTS OF ULTRAVIOLET-B RADIATION ENHANCEMENTS AND PAR FLUX
DENSITIES ON SEVERAL GROWTH PARAMETERS AS RELATED TO NCE,
DARK RESPIRATION, AND TRANSPIRATION OF SOYBEAN AND SEVERAL
GROWTH PARAMETERS OF WHEAT
Abstract
Plants were grown under four UV-B flux levels (simulating ozone
depletions ranging from 6 to 25%) with simultaneous exposure to four
PAR flux densities in a factorial design. Measurements were made
on the effects of each treatment on NCE, dark respiration, transpira-
tion, and growth of soybean (Glycine max (L.) Merr. cv Hardee). The
effects of UV-B on soybean growth were compared with wheat (Triticum
aestivum cv Jori). UV-B effects were dependent upon PAR flux densi-
ties incident during growth. Photorepair of UV-B induced NCE reduc-
tions was ineffective at low PAR fluxes, but was important at levels
saturating photosynthesis in the field. At low PAR levels, UV-B '
affected both stomatal and non-stomatal resistances to C0.2 and water
vapor. Wheat and soybeans were both affected by low level UV-B
enhancements, however, they differed markedly in their growth and
biomass allocation patterns. The present study points out the impor-
tance of the interactions between UV-B radiation and PAR in under-
standing the effects of UV-B on plant processes.
V-l
-------
Introduction
Vegetable and agronomic crops were grown in the field from March to
December 1977 under a gradient UV-8 irradiator under field conditions to
determine the crops response in regards to both vegetative and reproductive
capacities to enhanced UV-B radiation (Appendix 1-1). The crops tested
were *Silverqueen1 corn, potatoes, 'Walter' tomatoes, Southern peas, 'Flo-
runner' peanuts, yellow-neck squash, 'Star Bonnet1 rice, mustard and 'Red
Globe1 radish. The crops were grown under different UV-B gradients and
different UV-B attenuating cellulose acetate filters which are indicated
for each crop in Table 1. .
Materials and Methods
Field beds with open bottoms to natural soil were constructed with
sides of cypress posts and boards. Each bed measured 0.3 meters deep, 1
meter wide and 12.2 meters long. The entire construction site was fumigated
with methyl bromide. Redi-Earth soil mix supplied by W.R. Grace and Co. in
Jacksonville, Florida was used to fill the beds. It was fortified with
fertilizer and each crop was given additional fertilizer as required
(Table 2). Irrigation was supplied by placing a loop of Via-flo tubing in
each bed (Appendix 1-1) so that it was 8 cm from either side of the plants.
Tensiometers were used to regulate irrigation.
The field irradiator for UV-B enhancement consisted of 12 irradiator
units, each with 6 FS-40 Westinghouse "sun lamps" mounted end to end and in
IV-3
-------
Table 1. UV-B radiation enhancement levels in the field gradient irradiator
2 2
in total watts/m , (DNA) weighted mw/m and UV-B solar equivalent
units (seu).
Meter
1
2
3
4
5
6
7
8
Peanuts - Peas
Meter Weighted
1 17.253 1
2 6.763 0
3 3.775 0
4 3.166 0
:5 2.743 0
6 2.320 ' 0
7 1.801 0
8 1.013 0
Corn - Potatoes
Weighted
9.352
6.682
4.835
3.584
3.551
3.424
2.355
1.168
- Rice
w/m seu
.099 1.552
.431 0.608
.240 0.339
.202 0.285
.175 0.247
.148 0.209
.115 0.162
.065 0.091
- Tomatoes
. 2
w/m
0.596
0.426
0.308
0.228
0.226
0.218
0.145
0.074
Meter
1
2
' 3
4
5
6
7
8
seu
0.841
0.601
0.435
0.322
0.319
0.308
0.211
0.105
Squash - Mustard - Radish
2
.Weighted w/m
34.506 2.198 3
13.526 0.861 1
7.550 0.481 0
6.332 0.403 0
5.486 0.349 0
4.640 0.296 0
3.603 0.230 0
2.027 0.129 0
seu '
.104
.217
.679
.570
.493
.41?
.324
.182
IV-4
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Table 2
1977 Crop Culture.
Grot
M
<
Date planted
Thinning date
# pls./m.
Date & pesticide
Date kind and
g/meter of fert'J-
in 1.25 liters
per meter
Peas
7/1
8/1
6
7/14,
malthion
7/19,
lanate
July 22
thiodan
8/16,
thiodan
7/15, #1
10. 5g.
Aug. 16
5.3g.
Peanuts
6/17
7/27
6
7/14,
Malthion
7/22,
thiodan
8/11,
thiodan
8/16,
thiodan
7/6, #1,
10. 5g.
8/17, #2
9/15
5.3g.
Rice
6/24
8/4
10
7/15,
cap tan
10/4,
benlate
7/13, #1,
10. 5g.
8/11, #1,
'5.38.
9/15, #1,
5.3g.
10/14, #1,
5.3g.
Squash
9/9
10/3 .
6
9/23,
cygon,
10/4,
cygon
10/13, #1,
5.3g.
Mustard Radish
9/30 10/25
10/10 11/2
20 50
10/2,
cygon
.
11/14, #3, 11/14, #3,
10. 5g.
Harvest date
9/15
10/3
11/1
10/20
12/2
12/9
#1=20-20-20 fertilizer
#2=gypsum, 15 g/meter
#3=15-0-0 fertilizer
-------
an aluminum reflector (Appendix 1-2). The 6 lamps and reflector were
constructed as one unit. It was attached to pulleys and chains at either
end and the center so height adjustments could be made to establish the
desired gradient and to maintain it as the plants grew. The UV-B irradia-
tion gradient was established by raising and lowering the ends of each
irradiator unit to give an angle of 12ฐ. The lower end of the irradiator
was off-set by 3 meters from one end of the bed to give a non-irradiate
control section. Thus, the highest irradiance level was the 4th meter and
the lowest at the llth meter. The gradient was adjusted twice weekly.
Automatic timers controlled the FS-40 lamps for an on period for 6 hours in
the center of each day.
Each bed was fully planted. The first meter served as a buffer,
second as the untreated control and third as a buffer between the control
.and the lower end of the UV-B gradient receiving the highest UV-B enhancement
(Appendix 1-1). The 8 meters under the UV-B irradiance gradient received
different levels of UV-B enhancement (Table 1, Table 4). Each crop was
replicated in 4 separate field beds.
On April 28, 1977 a total and weighted UV-B flux between 295nm and
340nm was measured with the Gamma Scientific spectroradiometer. The UV-B
solar equivalent unit(UV-Bseu) was determined to be 11.2 W/m^ for the
weighted value and 7.08 W/m^ for the absolute value. In the field study,
when the weighted flux equaled 11.2 mW/m2 under an FS-40 lamp, the absolute
flux between 295nm and 340nm was 0.71 W/m^. with a 5 mil cellulose acetate
filter. These values were used as one UV-BSฃU for the UV-B enhancement
treatments.
As each crop was planted the Optronics, Model 741, spectroradiometer
equipped with a solar blind filter, a cosine receptor and a Hewlett-Packard
9815 A calculator was used to determine UV-B irradiance fluxes for adjusting
IV-6
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Table 3. Solarization of 3 mil and 5 mil cellulose acetate
in the field after 3 and 4 days as measured with an
Optronics 725 radiometer with a neutral density
filter. Each number is the mean of 23 measurements.
3 mil Cellulose Acetate
3 davs
5.66
4 days
5.50
5 mil Cellulose Acetate
Roll 1
Roll 2
3 days 4 days 3 days 4 days
2.73 2.67 3.16 3.05
Initial readings for 3 mil and 5 mil cellulose acetate were
set for 7.4 and 3.9 respectively.
TV-7
-------
Table 4. Natural solar UV-B flux (290-320nm), UV-B and enhancement in w/m
and solar equivalent units (seu) (290-320nm) on field grown crops
at the center of the 1st lamp in the gradient field. UV-B enhance-
ment measured twice each week with Optronics 725 radiometer and 725
radiometer calibrated weekly with Gamma Scientific and Optronics
741 spectroradiometer. Natural solar flux measured daily every
'2 hour between 9 a.m. and 4- p.m.
Crop Growing Dates
# Growing Days
Thickness C.A. used
"X UV-B w/m2
Bed 1
n 2
" 3
it i).
X" Bed w/rn2
X UV-B seu
Bed 1
n 2
" 3
i 4
6/17 to
10/3
Peanuts
108
5 mil
1.302
1.533
1.269
1.164
1.317
1.8390
2.1652
1.7924
1.6441
7/1 to
9/5
Peas
66
5 mil
1.243
1.225
1.212
1.226
1.234
1.7556
1.7302
1.7119
1.7316
9/9 to
10/20
Squash
44
3 mil
2.455
2.477
2.472
2.432
2.459
3.4675
3.4985
3.4915
3.4350
6/24 to
11/1
Rice
130
5 mil
1.350
1.330
1.350
1.345
1.040
1.9067
1.8785
1.9067
1.8997
9/30 to
12/2
Mustard
63
3 mil
2.513
2.495
2.509
2.521
2.510
3.5494
3.5240
3.5437
3.5607
10/25 to
12/9
Radish
45
3 rail
2.607
2.607
2.492
2.531
2.559
3.6822
3.6822
3.5198
3.5749
X Bed seu w/m
1.8601
1.7323
3.4731 1.8979
3.5444
3.6148
X Bed seu
Weighted (DNA) 20.6793
X" UV-B Solar Flux
During Crop Growth
Weighted (DNA) 12.7355
Total w/m2 6.5838
19.2584 38.6114 21.0995 39.4042 40.1868
10.8174 12.2998 11.3861 7.1566 4.546
5.4318 6.7518 6.1919 4.610 3.525
1 seu = 11.1173 weighted (DNA)
under natural sunlight conditions.
2 2
0.708 w/m under an FS-40 lamp and 708 w/m
IV-8
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the initial distance from the center of the first lamp to the soil surface
for the desired gradient. This UV-B enhancement level was set for .8 UV-Bseu
using 5 mil cellulose acetate filters for 'Silverqueen' corn, 'Irish'
potatoes and 'Walter' tomatoes, 1.5 UV-IJ for 'Southern' peas and 'Flo-
seu
runner' peanuts, 'Starr Bonnet' rice and 3.1 UV-B using 3 mil cellulose
seu
acetate filters for squash, mustard and radish (Table 1). After
the initial measurements were made, the UV-B flux was measured with a
Optronics 725 broad band UV meter sensitive up to 370 nm before and after
each changing of cellulose acetate filters which was done twice a week.
The "after" measurement was maintained at the same level by adjusting each
irradiator unit to yield UV-B enhancement levels from the center of this
first bulb to "plant height" at .8, 1.5 or 3.1 UV-B , depending upon the
seu s
crop. The "before" changing the filter measurements was used to determine
the amount of solarization (Table 3) and from this measurement an average
daily UV-B enhancement for the 3 or 4-day period was determined each time
filters were changed and lamps were checked. These values were then used to
arrive at the mean measured UV-B enhancement level actually obtained from
planting the crop to harvest (Table 1). Responsibility for UV-B enhancement
measurements was contracted for the first 3 crops. This was occasionally
done by lamp adjustment with a sun-burn radiometer. This was determined
not to be adequate and a different protocol was established by the project
coordinator for this most critical operation.
The natural solar irradiance of UV-B at ground level from 295-340 nm
was measured by nm every half hour from 10to 4 daily and a mean daily and
weekly flux computed. Measurements xvere taken with a Gamma Scientific
spectroradiometer and computer calculations made on a 2100 Hewlett-Packard
computer with a digital voltmeter and crossbar scanner (Appendix 1-4).
IV-9
-------
Seed was purchased locally except the rice seed which was donated by
Dr. Victor Green, Agronomy Department, University of Florida, Gainesville,
32611.
At maturity, all the plants in the control and the 8 meters in the
UV-B gradient flux were harvested from each bed. Parameters measured at
harvest and on seedlings at the time of harvest are discussed with each crop
but always included at least leaf area, leaf fr.esh and dry weight, stem
fresh and dry weight and root fresh and dry weight. Leaf area was determined
for all plants removed at the time of thinning. At harvest of mature
plants, leaf area was determined on the first plant of each meter of the
8 in the UV-B flux field and the control meters for. corn, potatoes, tomatoes,
peanuts, for the first 2 plants for Southern peas, for the first 3 plants
for rice and mustard and for the first 5 radish plants in each. All 4 bed
replicates were handled the same for each crop. A Lambda, model LI 3050 A,
leaf area meter with a high speed option was used to obtain leaf areas.
Fresh weights were measured to O.lg and dry weights to O.OOlg using a
digital top-load mettler balance.
To analyze the field data, polynomial regressions as to the amount of
UV-B enhancement were fitted sequentially beginning with a first order
S6U
(linear) model. The control was not used to estimate these equations. The
sequential process continued as long as (a) a significant increase in the
regression mean square was obtained and/or (b) the lack-of-fit mean square
was significant. Significance was determined using the error mean square
obtained by removing the total variation due to treatments and blocks. To
complete the analysis a comparison of the check with the treatment average
was made. All data in this report indicated significantly different at the
5% or less level.
IV-10
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I. 'Irish' potato . .
Irish'potato (Solanium tuberosum L.) tuber pieces were planted
March 18, 1977 & grown for 80 days to harvest on June 6, 1977. The crop was
fertilized every three weeks with 20-20-20 fertilizer at the rate of
10.5g/meter in 1.25 liters of water. UV-B enhancement was set for 0.84
UV-Bseu at the center of the first lamp and 5 mil cellulose acetate was
used (Table 4).
To determine if UV-B radiation altered the pattern of flowering, the
number of open flowers per plant were counted on May 2, 4 and 9
(Appendix 1-2). At harvest, data taken for all 6 plants in each meter of
the 4 replicate beds included: 1) leaf area (first plant in each meter
only), 2) leaf fresh and 3) dry weight 4) stem fresh and 5) dry weight,
6) root fresh and 7) dry weight and 8) total fresh and 9) total dry weight
biomass, 10) number and 11) weight of potatoes by 4 grades, 12) mean weight
of potatoes by 4 grades, 13) total number and 14) weight of potatoes, and
15) mean weight of potatoes.
II. 'Walter'tomato
'Walter'tomato (Lycospersicum esculentum Mill.) transplants were set
March 18, 1977, grown for 98 days &fruits harvested as they matured with
final harvest on June 24, 1977 (Appendix 1-2). They were fertilized every
3 to 4 weeks with 20-20-20 fertilizer at the rate of 10.5g/meter in 1.25
liters of water. UV-B enhancement was set for 0.84 UV-Bseu at the center
of the first lamp and 5 mil cellulose acetate was used (Table 4).
Determination of a possible alteration in the pattern of flowering was
followed by counting the number of flowers opening at the second and third
flower clusters (hands) on April 25, 27, 29 and May 4.
IV-11
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The tomatoes were harvested June 10 and 17 and these were fruit in
the advanced mature maturity class and some unmarketable fruit. Un-
marketable tomatoes consisted of 1) defective (catface, crooks and other
inherent defects); 2) culls (rots, cracks, sunscald and other impinging
defects and 3) immature (sound fruit less than 50g in weight). The second and
final harvest on June 24 included all the remaining fruit and these were
sorted into size and maturity classes. Fruits in the maturity class of
mature green were fully developed,- showing no red color. The size groups, equiv-
alent to USDA grading standards, were as follows: 1) 5 x. 6 and larger =
over 200g; 2) 6 x 6 = 150 - 200g; 3) 6x7= 100 - 150g; and 4) 7 x 7 =
50 - lOOg. Tomato fruit data taken from the 3 harvests was number, weight
of individual fruit and mean weight for each size or maturity class.
On June 24 all the plants were harvested and the following data taken
on each plant: 1) leaf area (first plant in each meter only), 2) leaf
fresh and 3) dry weight 4) stem fresh and 5) dry weight, 6) root fresh
and 7) dry weight and 8) total fresh and 9) dry weight biomass.
III. 'Silverqueen1corn
1Silverqueen corn'(Zea mays var. saccharate L.) was planted March 17,
1977 but was nipped by' frost at the end of the month. Frost at this stage can
decrease subsequent yields so the crop was replanted March 28, 1977, grown
for 75 days and harvested. The crop was fertilized every 3 to 4 weeks with
20-20-20 fertilizer at the rate of 10.5g/meter in 1.25 liters of water.
UV-B enhancement was set for 0.84 UV-Bseu at the center of the first 5 mil
cellulose acetate filtered lamp and the gradient set (Table 4).
The corn was thinned to 6 plants per meter. The number of silks per
ear of corn was counted May 23, 1977 and data taken on the corn ears at
IV-12
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harvest included 1) weight and 2) length of the whole ear, 3) weight,
4) length and 5) diameter of the trimmed ear and . 6) percentage of the ear
filled with kernels of marketable size. The trimmed ears had the shuck,
shank and silks removed. . '
At harvest, main stalk and sucker stalk data taken included 1) leaf
area (first plant/meter only) 2) stalk, and 3) tassel length, 4) stalk
fresh and 5) dry weight, 6) leaf fresh and 7) dry weight, 8) root
fresh and 9) dry weight 10) total fresh and 11) dry weight and for the
main stalks 12) internode number and 13) length. The number of suckers
was tallied for each plant as well as the height, of the tallest sucker
on each plant. Main stalk and sucker data was then combined to obtain a
whole plant 1) stem fresh and 2) dry weight, 3) leaf fresh and 4) dry
weight and 5) total fresh and 6) dry weight biomass for each plant in all
the meters (Appendix 1-2).
.IV. Southern peas .
Southern peas.(Vigna unguiculata L.) were planted July 1, 1977, grown
for 166 days and harvested September 5, 1977 (Appendix 1-2). The crop was
sprayed for aphids 4 times using malthion, lanate or thiodan. A 20-20-20
fertilizer was applied twice, first at 10.5 g/meter on July 15, and then
5.3 g/meter on August 16 in 1.25 liters of water per meter (Table 2). UV-B
enhancement was set for 1.5 UV-Bseu's at the center of the first lamp and
5 mil cellulose acetate was used (Table 4).
On August 1, 1977, the peas were thinned (7 to 19 seedlings per meter
removed) to 6 plants per meter. Data taken on each removed seedling by
meter was 1) total leaf area, 2) leaf fresh and 3) dry weight, 4) stem
fresh and 5) dry weight and 6) root fresh and 7) dry weight, 8) total
IV-13
-------
fresh and 9) dry weight biomass, 10) root:shoot ratio 11) leaf.density
(leaf area divided by leaf dry weight) 12) % leaves 13) % stems 14) %
roots.
Beginning 57 days after planting the marketable peas were harvested by
meter, counted and fresh weights determined every 3 or 4 days for 5 harvests.
The final harvest data taken on each plant included 1) leaf area (first
.plant/meter only) 2) leaf fresh and 3) dry weight, 4) stem fresh and 5)
dry weight, and 6) root fresh and 7) dry weight 8) total fresh and 9)
dry weight biomass 10) root:shoot ratio and 11) leaf density, 12) % leaves
13) % stems, and 14) % roots. Total leaf area was taken on the first two
plants in each meter.
V. ' Florunner'peanuts
'Florunner'peanuts(Arachis hypogaea L.) were planted June 17, 1977, grown
for 108 days and harvested October 3, 1977 (Appendix 1-3). The crop was
sprayed 4 times with thiodan or malthion, fertilized twice with 20-20-20
fertilizer at the rate of 10.5 g/meter> (July 6) and 5.3 g/m (September 15)
in 1.25 liters of water. Fifteen grams gypsum per meter x^as applied August
17, 1977, one week after flowering (tTable 2). UV-B enhancement was set for
.1.5 UV-B seu's at the center of the first lamp and 5 mil cellulose acetate
was used (Table 4).
Five to eight peanut seedlings per meter were removed to obtain an even
stand of 6 plants per meter on July 27, 1977. Data taken for each seedling
included 1) leaf area .... 2) leaf fresh and 3) dry
weight, 4) stem fresh and 5) dry weight and 6) root fresh and 7) dry
weight 8) total fresh and 9) dry weight biomass 10) root:shoot ratio 11)
leaf density 12) % leaves, 13) % stems and 14) % roots.
Harvest began October 3. Data taken on each plant was 1) leaf area
2) leaf fresh and 3) dry weight, 4) stem fresh and 5) dry weight, and
6) root fresh and 7) dry weight 3) total fresh and 9) dry weight biomass
IV- .14
-------
10) root:shoot ratio, 11) leaf density, 12) % leaves, 13) % stem, 14)
% roots, 15) total number of pop (unfilled ) peanuts, 16) weight of the
pops 17) total number of filled peanuts, 18) weight of the filled peanuts
and 19) plant height.
VI. 'Star Bonnet' rice
'Star Bonnet' rice (Oryza sativa L.) was planted June 24, 1977, grown, for
130 days and harvested November 1, 1977 (Appendix 1-3,4). The crop was
sprayed July 15 with captan and October 4 with benlate. A 20-20-20 fertil-
izer was applied July 13, August 11, September 15 and October 14 at the
rate of 10.5 g/meter, 5.3 g/meter, and 2.6 g/meter all in 1.252, 1^0 on in-
dicated dates, respectively (Table 2). UV-B enhancement was set for 0.8
UV-Bseuat the center of the first lamp and 5 mil cellulose acetate was used
(Table 4).
Five to 26 rice seedlings per meter were removed in thinning the
crop to 10 plants per meter. Data taken for each seedling included 1) leaf
area, 2) leaf fresh and 3) dry weight 4) stem fresh and 5) dry weight
and 6) root fresh and 7) dry weight, 8) total fresh and 9) dry weight
biomass 10) leaf density, 11) % leaves, 12) % stems and 13) % roots.
Rice height for each plant in all meters was measured every week for 15
weeks after seedling emergence.
At harvest each tiller of the plant was analysed separately for the
first 3 control plants, the first 3 plants in meter one and the first plant
in every meter thereafter under the UV-B gradient. The number of tillers
per plant ranged from 10 to 26. The following parameters were measured and -
observations made for each tiller: 1) fruiting or vegetative tiller, 2)
leaf fresh 3) and dry weight, 4) stem fresh 5) and dry weight, 6) root
fresh 7) and dry weight, 8) spike length, 9) spike fresh 10) and dry
IV-15
-------
weight, 11) stage of spike development, 12) height to spike base, 13)
number of leaves/tiller, 14) leaf area minus flag leaf, and 15) flag
leaf area 16) length, 17) fresh weight, 18) dry weight, and 19) leaf
specific thickness or density, 20) total # of tillers.per plant, 21) total
dry weight biomass/tiller, 22) root:shoot ratio/tiller, and 23) tiller
leaf specific thickness or density.
The .stage of spike development was determined by rating the amount of
the spike which had turned brown: no broxra = 1, 1/4 = 2, % = 3, 3/4 = 4,
and all brown = 5.
On the remaining plants in each meter, parameters 1 to 11 and 21 to 24
were measured in addition to talleying the number of vegetative vs. fruiting
tillers.
VII. Yellow Crooked-neck squash
Squash (Cucurbita pepo var. condensa Bailey) were planted September
<
9, 1977 grown for 41 days and harvested just as they began to bear fruit
because of cool weather, (Appendix 1-3). The crop was sprayed twice for
leaf minor with cygon and fertilized October 13 with 5.3 g of 20-20-20 fer-
tilizer per 1.25 liters of water per meter (Table 2). UV-B enhancement was
set for 3.1 UV-B seu's at the center of the first lamp and 3 mil cellulose
acetate used (Table 4).
When the squash were thinned October 3, 1977 to 6 plants meter, each
removed seedling was measured for 1) total leaf area, 2) leaf fresh and
3) dry weight, 4) stem fresh and 5) dry weight, 6) root fresh and 7)
dry weight, 8) total fresh and 9) dry weight biomass 10) root:shoot ratio,
11) leaf density, 12) % leaves, 13) % stems 14) % roots and 15) height.
At final harvest, October 20, frost had damaged the leaves so leaf
area was not taken. Data taken included: 1) leaf fresh and 2) dry weight
3) stem fresh and 4) dry weight, 5) root fresh and 6) dry weight 7) total
IV-16
-------
fresh and 8) dry weight biomass 9) rootrshoot ratio, 10) % leaves, 11) %
stems 12) % roots 13) number of fruit and 14) fresh weight of fruit and
15) mean weight per fruit. ' .
VIII. Mustards
Mustards (Brassica juncea var. cripifolia) were planted September 20,
1977, grown for 63 days and harvested December 2, 1977 (Appendix 1-4).. The
crop was sprayed November 2 with cygon for leaf miners and fertilized with
' 15-0-15 fertilizer November 14 at the rate of 10.5 g/meter in 1.25 liters of
water (Table 1). UV-B enhancement was set for 3.5 UV-B seu, at the center
of the first lamp and 3 rail cellulose acetate was used (Table 4). The mus-
tards were thinned to 20 plants per meter on October 10, 1977. At harvest,
data taken included 1) leaf area 2) leaf fresh and 3)dry weight 4) root
fresh and 5) dry weight 6) total fresh and 7) dry weight biomass, 8) root:
shoot ratio, 9) leaf density 10) % leaves, 11) % roots and 12) number of
leaves per plant.
IX. 'Red globe'radish
'Red globe'radish seed (Raphanus sativus L.) were planted October 25, 1977,
grown for 45 days and harvested December 9, 1977 (Appendix 1-1). The crop
was thinned to 50 plants per meter and fertilized November 14 with a 15-0-15
fertilizer at the rate of 10.5 g/meter in 1.25 liters of water (Table 2).
UV-B enhancement was set for 2 solar units at the center of the first lamp
and 3 mil cellulose acetate was used (Table 4). At harvest,data taken in-
cluded 1) leaf area on the first 5 plants, 2) leaf fresh and 3) dry weight,
J
and 4) root fresh weight 5) total fresh weight, 6) leaf density and 7)
number of leaves per plant.
IV-17
-------
Results
I. 'Irish'potatoes
The number of open flowers per plant peaked on May 4 and at this time
the UV-B treated plants had considerably more open flowers than the control
(Table 5). The duration of flowering was apparently longer on the control
plants. Mean potato weight was consistently larger for the grade A large
in the UV-B treated meters but the other grades were all similar (Table 6).
Significant linear relationships were found for total plant dry weight
biomass and leaf dry weight among the UV-B meters (Table 7) The dry weights
increased with increasing UV-B as approximated by the equations 88.6 + 26.8X
and 211.9 + 57.3X for leaf dry weight and dry weight biomass, respective-
ly. The other vegetative parameters were all similar.
II. 'Walter'tomatoes
Flowering on the second and third panicle (hand) was tallied since these
'reproductive buds were initiated under exposure to UV-B radiation. First
panicle flowers were initiated prior to transplanting. The flowering pat-
tern was similar among the meters except that the number of flowers on the
second hand on May 4 of control plants was significantly greater than the
UV-B irradiated plants (Table 8).
Exposure to UV-B significantly reduced the number and weight of tomatoes
in the 5x6 size class at the second harvest (Tables 9, 10 and 11). The aver-
age of all UV-B treated plant was significantly less than the control for the
following maturity classes:
1. Advanced Mature, Harvest 2, 5x6, number of tomatoes
2. Advanced Mature, Harvest 2, 5x6 weight of tomatoes
3. Mature Green, Harvest 2, 5x6, number of tomatoes
4. Mature Green, Harvest 2, 5x6 weight of tomatoes
5. Marketable, Harvest 2, 5x6, number of tomatoes
6. Marketable, Harvest 2, 5x6, weight of tomatoes
7. Advanced mature, total, 5x6, number of tomatoes
8. Advanced mature, total, 5x6, x
-------
Table 5 Potato leaf area at harvest and number of flowers.
Open Flowers per Plant
Meter
1
2
3
4
5
6
7
8.
Leaf^Area
on
4496
6430
5196
6110
8586
6364
4372
3175
3770
May 2
.11.7
17.6
9.9
7.1
13.4
13.9
10.4
9.2
May 4
13.1
22.4
26.7
20.4
9.9
20.5
25.3
16.4
20.0
May 9
TOT
9.7
10.6
10.7
11.3
11.2
13.5
5.0
9.6
weans from 4 field beds, each with 9 meters and 6 plants per meter at har-
vest. Leaf area determined only on the first plant in each meter and
flower number on all plants.
Tfeter 0 = No UV-B, control; meter 1 = first meter under the UV-B gradient
irradiator.
IV-19
-------
Table 6. Potato yields at harvest .
f
s-
x
Meter Average by Grade
A Large
Meter
0
1
2
3
4
5 '
6
7
8
s-
X
V.'t.(g)
2683
2138
2328
.1749
2316
3216
3178
1880
2205
389.7
x Wt.(g)
173
191
176
177
178
190
195
177
176
No
15.
11.
13.
9.
13.
16.
16.
10.
12.
2.
.
5
2
2
9
0
9
3
6
5
19
Wt.(g)
2462
2233
1899
2329
2417
1746
2094
2634
2521
291.5
x Wt.(g)
99
99
101
100
103
102
105
102
99
No
24.
22.
18.
23.
23.
17.
20.
25.
25..
2.
.
8
5
8
2
5
1
0
8
4
92
Wt(g)
972
1163
714
1012
864
878
835
1290
835
175.1
x Wt.(g)
49
47
48
47
46
48
47
51
48
No.
20.0
24.5
14.8
21.5
18.6
18.4
17.8
25.1
17. :4
3.63
C Creamer
Total
^
Meter
. 0
1
2
3
4
5
6
7
8
V,Tt.(g)
238
340
' 302
407
224
333
260
292
273
x Wt.(g)
18
17
15
16
19
18
18
20
17
No.
13.0
19.5
19.8
24.9
11.5
18.3
14.2
14.4
15.8
Wt.(g)
6355
5874
5244
5497
5822
6174
6368
6095
5833
x Wt.(g)
87
76
79
69
87 .
87
93
SO
82
No.
78.2
77.8
66.5
79.5
66. G
70.6
68.2
75.8
71.1
105.8
6.75
530.8
9.21
Means from 4 field beds, each with 9 meters and 6 plants per meter at harvest.
Meter 0 = No UV-B, control; meter 1 = first meter under the UV-B gradier.T irradiator.
-------
Table 7. Potato plant harvest data.
Root(g)
Stem(g)
Leaf(g)
Total(g)
Meter
10
1
2
3
4
5
6
7
8
Fresh
55.9
55.0
52.1
51.2
49.7
59.7
50.5
53.6
53.8
Dry
7.16
7.80
6.16
7.08
6.76
5.74
8.12
5.42
6.11
Fresh
257
283
267
254
274
283
259
251
258
Dry
16.9
23.1
17.9
18.5
19.1
14.3
19.9
15.1
14.9
Fresh
204
210
187
179
174
. 205
168
147
177
Dry
. 21.1
23.9
17.2
19.8
19.6
15.3
19.2
14.6
15.7
Fresh
518
548
506
484
499
548
478
451
489
Dry
45.2
54.9
41.3
45.4
45.5
35.4
47. '3
35.1
36.7
f
KJ
X
5.228
0.823
25.88
2.055
22.13
2.327
49.22
4.813
Means from 4 field beds, each with 9 meters and 6 plants per meter at harvest.
"Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient irradiator.
-------
Table 8. Walter tomato leaf area at harvest and number of flowers on the second and third hand .
Number of Flowers per Plant
M
f
t-O
INJ
Meter
0
1
2
3
4
5
6
7
8
Leaf Area .
9734
8075
6810
9521
9054
8639
8705
7544
12660
April
Second
4.1
3.5
3.5
3.3
. 3.3
. 2.6
3.9
3.9
2.5
25
Third
1.3
0.9
1.9
1.6
1.8
1.2
2.2
2.4
1.0
'April
Second
3.5
3.9
3.5
2.8
2.4
2.8
3.4
3.7
2.4
27"
Third
1.5
1.6
1.5
1.4
1.4
0.9
1.8
1.1
0.7
' April
Second
2.5
2.9
2.4
1.9
2.6
3.1
1.9
2.1
2.6
29
Third
2.8
2.9
2.5
2.4
2.2
2.1
2.1
2.1
2.1
May
Second
2.1
1.8
1.1
0.9
0.9
1.1
0.8
1.1
1.0
4
Third
1.6
2.0
2.5
1.8
1.9
2.5
2.2
2.7
1.8
Means from 4 field beds, each with 9 meters and 3 plants per meter at harvest.
'Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient irradiator.
Indicates average of all UV-B treatments was significantly less than control.
-------
IS3
UJ
Table 9. Harvest data by USDA grading standards for Advanced Mature Walter tomatoes of the second harvest .
Advanced Mature, Harvest 1
3
Meter
0
1
2
3
4
5
6
7
8
s-
X
No.
22.8
19.1
21.0
18.8
17.3
16.5
18.3
20.5
16.8
2.740
5x62
xWt(g)
211
200
215
209
216
213
215
209
220
Wt(g)
4802
3826
4519
3920
3724
3515
3925
4276
3681
622.2
No.
5.5
9.8
7.0
9.0.
4.0
6.5
9.5
6.3
7.8
1.760
6x6
xWt(g)
141
148
144
139
144
144
141
147
142
Wt(g)
111
1442
1008
1254
576
934
1335
916'
1099
250.1
Advanced
Meter
0
1
2
3
4
5
6
7
8
s-
X
No.
14.5
7.5
10.0
8.5
10.3
10.8
11.0
13.0
11.0
1.912
5x6
xWt(g)
208
194
206
200
, 207
193
198
199
208
Wt(g)"
3017
1454
2061
1699
2122
2072
2180
2583
2288
274.4
No.
5.5
7.1
6.5
5.3
5.3
5.8
6.5
5.5
7.3
1.464
6x6
xWt(g)
144
142
145
141
139
143
142
140
145
Wt(g)
791
1011
941
740
732
. 822
924
111
1048
205.6
No.
5.3
3.8
7.3
3.8
6.0
3.0
. 7.3
5.0
3,5
1.775
Mature
No.
4.0
1.9
5.5
4.8
1.5
2.8
4.8
2.0
5.0
1.486
6x7
xWt(g)
118
113
116
115
116
117
110
119
114
Wt(g)
620
422
844
430
693
352
795
596
400
205.7
No.
0.8
1.5
0.8
1.0
2.8
2.0
2.0
1.5
1.3
0.883
7x7
xWt(g)
93
64
93
45
31
78
43
57
74
Wt(g)
. 70
96
70
45
85
156
86
85 .
92
41.8
No.
34.3
34.1
36.0
32.5
30.0
28.0
37.0
33.3
29.3
3.442
Total
xWt(g)
183
170
179
174
169 .
177
166
177
180
Wt(g)
6270
5787
6440
5650
5078
4958
6141
5873
5272
608.4
, Harvest 2
6x7
xWt(g)
114
110
113
112
110
116
115
113
113
t
Wt(g)
457
206
622
532
165
318
548
226
566
167.1
No.
1.3
0.4
2.5
1.3
0.5
1.5
3.5
0.8
2.3
0.858
7x7
xWt(g)
88
92
86
90
92
87
87
89
30
Wt(g)
110
35
214
112
46
130
303
67
180
76.5
No.
25.3
16.9
24.5
19.8
17.5
20.8
25.8
21.3
25.5
3.407
Total
xWt(g)
173
160 .
157
156
175
161
154
192
160
Wt(g)
4374
2706
3838
3083
3066
3342
3955
3648
4082
468.8
Means from 4 field beds, each with 9 meters and 3 plants per meter at harvest.
^Grade 5x6 - over 220g; 6x6 = 150-200g; 6x7 = 100-150g; 7x7 = 50-100g.
Meter 0 = no Uy-P control; meter 1 = first meter under the UV-B gradient irradiator.
* indicates average of all UV-B treatments was significantly less than the control.
-------
Table 10. Harvest data by USDA grading standards for the second Wa.lter tomato harvest according to marketable
and mature green stages of development. *
Mature - Green Harvest'
M
<
3
Meter
0
1
2
3
4
5
6
7
3
s
X
No.
1.8
1.1
0.8
0.0
1.3
0.3
0.5
0.5
0.5
0.471
5x6
Ave.Wt(g)
221
201
171 .
0
190
200
180
170
196
Wt. No.
387 1.3
225 0.8
128 0.5
0 1.3
237 0.8
50 1.0
90 0.5
85 1.0
98 0.8
98.0 0.594
6x6
Ave.Wt(g)
141
133
144
141
139
135
136
150
147
Wt. No.
176 i.O
100 0.0
72 0.8
176 1.0
104 1.0
135 0.8
68 1.5
150 0.8
110 1.8
81.3 0.490
6x7
Ave.Wt(g)
112
0
111
113
103
109
111
112
113
Wt.
112
0
83
113
103
82
166
84
198
55.6
No.
0.8
0.8
1.3
0.3
0.0
1.3
1.0
0.3
1.0
0.446
7x7
Ave.Wt(g)
92
88
93
84
0
90
93
96
87
Wt.
69
66
116
21
0
112
93
24
87
39.8
No.
4.8
2.6
3.3
2.5
3.0
3.3
3.5
2.5-
4.0
0.985
Total
Ave.Wt(g)'" Wt."
Ib /
149
123
124
148
116
119
137
123
744
391
399
310
445
378
418
343
492
147.7
o
Marketable, Harvest
Meter
0
1
2
3
4
5
6
7
8
s
X
No."
16.3
8.6
10.5
8.5
11.5
11.0
11.5
11.5
11.5
1.722
5x6
A ve.WtCg )V:
209
195
204
200
205
193
' 197
198
207
Wt." No.
3404 6.8
1678 7.9
2190 7.0
1699 6.5
2359 6.0
2121 6.8
2270 7.0
2668 6.5
2386 8.0
6x6
Ave.Wt(g)
143
141
145
141
139
142
142
142
145
347.2 1.765
Wt. No.
967 5.0
1111 1.9
1013 6.3
917 5.8
836 2.5
957 3.5
992 6.3
922 2.8
1157 6.8
246.5 246.5
6x7
Ave.Wt(g)
114
110
113
112
107
114
114
112
113
Wt.
569
206
705
645
268
.400
715
309
764
174.2
No.
2.0
1.1
3.8
1;.5
0.5
2.8
4.5
1.0
3.3
0.983
7x7
Ave.Wt(g)
89
90
88
89
92
88
88
91
82
Wt.
178
101
330
133
46
242
496
91
267
87.1
No.
30.0
19.5
27.8
22.3
20.5
24.0
29.3
23.8
29.5
3.444
Total
Ave.Wt(g)
171
159
153
153
171
155
150
168
155
" Wt."
5119
3097
4237
3394
3510
3720
4373
3991
4574
453.6
Means from 4 field beds, each with 9 meters and 3 plants per meter at harvest.
^Grade 5x6 = over 200g; 6x6 = 150-200g; 6x7 = 100-150g; 7x7 = 50-100g.
Meter 0 = no UV-3 control; meter 1 = first meter under the UV-B gradient irradiator.
" indicates average of all UV-B treatments was significantly less than the control.
-------
Table 11. Harvest data by USDA grading standards for Advanced mature Walter tomatoes of both harvests .
5x6
Advanced Mature, Harvest 1 and 2"
6x6 6x7
7x7
Total
M
<
Is3
Ul
3
Meter
0
1
2
3
4
5
6
7
8
No."4 Ave.Wt(g)" Wt."
37.3 .
26.6
31.0
27.3
27.5
27.3
29.3
33.5
27.8
210
198
212
206
213
205
209
205
215
7820
5280
6580
5619
5846
5587
6105
6859
5869
No. Ave.Wt(g) Wt.
11.0
16.9
13.5
14.3
9.3
12.3
16.0
11.8
15.0
143
145
144
140
141
143
141
144
143
1568
2453
1948
1995
1308
1756
2259
1688
2146
No. Ave.Wt(g) Wt.
9.3
5.6
12.8
8.5
7.5
5.8
12.0
7.0
8.5
116
112
115
113
114
117
112
117
114
1077
628
1466
962
858
670
1343
822
966
No. Ave.Wt(g) Wt.
2.0
1.9
3.3
2.3
3.3
3.5
5.5
2.3
3.5
90
70
87
70
40
82 .
71
68
78
180
132
284
157
131
286
389
152
272
No. Ave.Wt(g) Wt."
59.5
51.0
60.5
52.3
47.5
48.8
62.8
54.5
54.8
179
167
170
167
171
170
161
171
171
10645
8493
10278
8733
8144
8300
10096
9521
9354
s-
X
3.021
650.2 2.318
322.8 2.703
308.5 1.325
88.5 4.680
648.6
Means from 4 field beds, each with 9 meters and 3 plants per meter at harvest.
2Grade 5x6 - over 200g; 6x6 = 150-200g; 6x7 = 100-150g; 7x7 = 50-100g.
Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient.irradiator.
4...
" indicates average of all UV-B treatments was significantly less that the control.
-------
10. Total weight, marketable, harvest 2
11. Total weight, total advanced mature
In addition, significant linear relationships existed among advanced
mature 5x6 weight class, mature green 6x7 weight class and mature green 6x7
number of fruit for tomatoes in the second harvest. The regression equations
of decreasing weight and number are indicated in Table 12.
With UV-Bseu's of .44 or greater, the number of culls in the second
harvest tended to be lower as did the number of defective fruits in the first
harvest (Table 13).
At harvest all the plants were analysed for leaf, stem, root and total
fresh and dry weight. Leaf area was taken on the first of each of the 3
plants in each meter. The stem and total dry weight for the control was sig-
nificantly greater than the mean of all UV-B treatments (Table 14). In addi-
tion, significant quadratic relationships were found among the UV-B treat-
ments for leaf fresh and dry weight, stem dry weight and total dry weight
(Table 13).
III. ' Silverqueen' corn
The main stalk of control plants were found to be significantly taller
than those of the UV-B treated plants (Table 15). This was reflected in
significantly greater stalk and plant total fresh weight for the control.
Main stalk dry weights and tassel lengths for the control plants were also
greater but the magnitude was not statistically significant. Reductions in
leaf fresh and drv weight were observed for UV-B , of .84 to .44 (meter
0 seu s
1-3 but were similar to the control for lower enhancement levels of .32 -
.10 UV-BSeu (meters 4-8). Root fresh and dry weight were generally less
than the controls for all but one meter. Tassel length on the main stalk,
internode number and mean length were all similar among the treated and
control plants. Leaf area was greater for the control plants except for
the last UV-B treated meter receiving .11 UV-B , (Table 15). Main stalk
seu s
IV-26
-------
Table 12. Walter tomato fruit and plant responses showing significant
relationships among the UV-B treatments and their correspond-
ing regression equations .
Response Equation
/
Advanced Mature, .Harvest 2, 5x6 Wt. 2469.8 - 53S.5 X
Mature Green Harvest 2, 6x7 no. 1.55 - 0.795 X
Mature Green, Harvest 2, 6x7 Wt. 171.5 - 88.6 X
Leaf Fresh Weight 395.8 - 210.1 X + 105.6x2
Leaf Dry Weight . 56.6 - 32.3 X + 16.7 X2
Stem Dry Weight 83.9 - 54.4 X + 31.6 X2
Total Dry Weight 155.1 - 84.4 X + 46.7 X2
A = UV-B enhancement in solar equivalent units (seu).
IV-2 7
-------
Table 13. Walter tomato harvest data for immature, defective and cull
tomatoes^-.
Harvest 1
Harvest 2
2
Meter
0
1
2
3
4
f
t-o
6
7
8
Culls
No.
0.25
0.38
0.50
0.75
0,00
0.00
0.75
0;00
0.00
Wt.(g)
20
30
40
59
0
0
50
0
0
Defective
No.
7.3
6.4
4.3
5.8
5.0
4.5
8.5 .
6.5
4.8
Wt. (g)
1278
831
600
838
786
878
1500
1370
808
Immature
Wt. (g)
162
131
281
122
59
224
70
92
182'
'Culls
' No.
15.5
12.0
14.3
12.0
14.5
13.5
20.8
17.0
19.0
Wt. (g)
1314
968
1386
1202
1555
1147
1914
1583
1756
s- 0.270
x
19.7 . 1.343
317.2
88.4
3.009
366.4
Means from 4 field beds, each with 9 meters and 3 plants per meter at harvest.
"Meter 0 = no UV-B control; meter 1 = first meter under the UV-B gradient irradiator.
-------
Table 14. Walter tomato plant harvest data .
Leaf (g)
Stem (g)
Root (g)
Total (g). .
M
r
NJ
\0
2
Meter
0
1
2
3
4
5
6
7
8
Fresh
352
345
295
301
325
290
337
296
380
Dry
52
50
42
43
45
40
48_
. 43
53
Fresh
700
635
609
620
589
539
702
606
> 662
Dry*3
79
85
63 :
60
64
62
73
66
72
Fresh
78
60
66
61
65 .
68
89
77
57
Dry
18
15
13
13
15
13
22
17
12
Fresh-
1131
1041
971 ;
982
979
897
1127
979
1099
Dry*
150
151
118
116
' 124
115
143
126
'137
s-
X
21.97
3.303
39.10
5.376
8.177
2.646
57.4
9.22
Means from 4 field beds, each with 9 meters and 3 -plants per meter at harvest.
2
. Meter 0 = no UV-B control; meter 1 = first meter under the UV-B gradient irradiator.
* indicates average of all UV-B treatments was significantly less than the control.
-------
Table 15. Silverqueen corn main stalk harvest data .
Length (cm) Internode(cm) Stalk Wt.(g) Leaf Wt.(g) Root Wt.(g) Total Wt.(g)
Meter
0
1
2
3
4
5
6
7
8
Stalk*3
198
191
187
198
198
195
189
189
184
Tassel
60
54
58
56
57
60
63
56- .
56
No.
9.7
9.6
9.6
9.8
10.0
9.7
9.7
9.7
9.5
Length
19.6
19.9
19.6
20.3
19.8
20.2
19.5
19.3
19.4
Fresh*
593
492
. 550
588
577
576
572
555
540
Dry
133
94
116
130
127
130
142
142
123
Fresh
155
144
148
154
167
156
159 ^
167
146
Dry
34
31
32
34
35
33
34
35
33
Fresh
435
209
245
338
374
244
287
282
294
Dry
101
64
76
98
104
73
79
82
97
Fresh*
1183
846
943
1080
1119
973
1018
1004
981
Dry
269
189
224
262
266
236
254
260
253
s-
X
3.05
3.463 0.157.0.386 14.99 10.76 8.98 1.716 69.67 13.21 72.5 18.07
Means from 4 field.beds, each with 9 meters and 6 plants per meter at harvest.
"Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient irradiator.
* indicates average of all UV-B treatments was significantly less than the control.
-------
parameters showing significant relationships with increased UV-B enhance-
ment and their regression equations are indicated in Table 16.
Analysis of the suckers on each plant showed that the number of suckers,
height of the tallest sucker and number of silks per ear was significantly
less for UV-B treated than control plants (Table 17). However, for other
vegetative parameters of sucker stalks there were no significant differences
observed (Table 18). Sucker stalk dry weight and total dry weight showed
significant relationships within the UV-B enhancements which were estimated
by the following equations: 32.0 - 7.5 X and 47.2 - 9.4X for stalk dry
weight and total dry weight respectively when X is the UV-B enhancement.
06 U
On a whole plant basis the aberage of the control was found to be signi-
ficantly higher than the average of the UV-B treatments for stalk fresh weight,
leaf dry weight, total fresh weight and total dry weight (Table 19). Signi-
ficant relationships were found for all 6 responses and the regression equa-
tions are found in Table 20. Stalk Dry weight decreased linerly with UV-B.
enhancement. .
Harvest data on the ears included length, diameter of entire and trimmed
ear and percent fill values. All of parameters were decreased at .84 UV-B
seu
but not at lesser UV-B enhancement levels. No significant differences
were observed for plants from any of the meters in the regression analysis
(Table 21) but an F - test to compare the 0.84 UV-B enhancement vs just
S GU
the control meter indicated that weight of the entire ear and diameter was
significantly decreased.
IV. Southern Peas
Seven to 19 seedlings per meter were removed 31 days after planting,
leaving 6 plants per meter to mature. The treatment means and the estimates
of their standard errors are given in Table 22. Leaf, stem, root and total
fresh and dry weights tended to be less in the treated than control meters.
IV-31
-------
Table 16. Silver queen corn main stalk parameters showing significant
relationships among the UV-B treatments and their corres-
ponding repression equations .
Response Equation
Stalk Length 179.4 + 33.6X - 17.OX2
Stalk Fresh Weight 502.5 + 201.2X - 122.8X2
Stalk Dry Weight 144.4 - 24.6X
Total Fresh Wieght 886.8 + 436.8X - 276.8X2
Total Dry Weight 274.1 - 40.6X
A = UV-B enhancement in solar equivelent units (seu).
IV-32
-------
Table 17. Harvest data for Silverqueen corn main and sucker stalks..
M
1
UO
U!
2
Meter
0
1
2
3
4
5
6
7
8
Lf Area
cm-
3957
3445
3743
3305
3697
3901
3639
3947
3655
No.
Suckers"
3.4
3.8
2.7
2.7
2.6
2.7
2.9
. . 2.8
.2.5
No.
Silks
2.0
1.6
1.8
1.7
1.6
1.8
1.9
1.4
1.6
Tallest Sucker Height (cm)
PI 1*
74
53
54
48
64
50
67
58
61
PI 2*
76
52
64
54.
63
41
58
65
61
PI 3*
75
50
55
61
47
58
65
56
61
PI 4*
76
57
58
55
52
52
58
56
53
PI 5*
75
64
58
71
50
66
56
61
59
PI 6*
73
61
52
.53
55
67
74
59
50
Ave.
75
56
57
57
55
57
63
59
59
Means from 4 field beds, each with 9 meters and 6 plants .per .meter at harvest. Leaf area for
main stalk only. * indicates, average of all UV-B treatments was significantly less than the control,
2
Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient irradiator.
-------
Table 18. Silverqiieen corn harvest data on sucker stalks .
M
f
*
Meter
0
1
2
3
4
5
6
7
8
Stalk
95
89
100
106
107
105
109
107
99
Tassel
24 '
24
24
28
33
28
28
' 36
29
Fresh
137
89
131
135
127
130
146
151
125
Dry
27
18
24
26
22
27
30
32
30
Fresh
58
47
59
63
67
55
62
74
52
Dry
13
11
13
14
16
13
-14
16
12
Fresh
195
136
190
197'
194
185
208
224
177
Dry
40
29
37
40
38
40
44
49
42
s- 14.24 5.205 19.83 4.586 7.042 1.745 25.20 5.991
X
Means from 4 field beds, each with 9 meters and 6 plants per meter at harvest.
2
Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient.irradiator.
-------
Table 19. Silverqueen corn whole plant harvest data .
Stalk Wt-(g) Leaf Wt(g) Total Wt(g)
Meter
0
1
2
3
4
5
6
7
8
sx
Fresh
906
597
754
820
766
/5*8
806
741
752
44.44
Dry
194
116
154
175
161
177
196
183
173
13.83
Fresh
274
199
241
262
267
247
253
252
235
15.68
Dry
62
.43
53
58
58
56
56
55
54
3.467
Fresh
1697
1017
1276
1450
11-40
. 1329
1396
1318
1307
104.5
Dry"
376
226
290
339
331 .
315
344
332
329
22.88
Means from 4 field beds, each with 9 meters and 6 plants per meter at
harvest.
2
Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient
irradiator.
3
" indicates average of all UV-B treatments was significantly less than
the control . .
IV- 35
-------
Table 20. Silverqueen corn whole plant parameters showing
significant relationships among the UV-B treat-
ments and their corresponding repression equations .
Response Equation
Stalk Fresh Weight 665.1 + 370.3X - 238.5X
Stalk Dry Weight 197.4 - 40.IX
Leaf Fresh Weight 211.1 + 129.IX - 80.5X2
Leaf Dry Weight 48.7 + 24.OX - 15.81X2
Total Fresh Weight 1138.6 + 744.7X - 480.9X2
Total Dry Weight 304.6 + 106.7X - 89.5X2
A = UV-B enhancement in solar equivalent units (seu).
iv-36
-------
Table 21. Silverqueen corn harvest data .
2
Meter
0
1
2
3
4
5
6
7
8
Sjc
Entire
308
292
327
313
344
324
324
289
310
15.40
Trim
216
207
234
220
244
228
227
204
225
11.45
Entire
31.6
30.6
31.5
31.4
31.0
31.3
32.2
30.7
30.5
0.716
Trim
17.1
17.0
17.6
17.3
17.9
17.4
17.6
17.1
17.2
0.450
Diam(cm)
4.49
4.38
4.53
4.45
4.50
4.52
4.53
4.38
4.47
0.079
%Fill
91
90
95
95
95
92
90
92
99
2.324
Tfeans from 4 field beds, each with 9 meters and 6 plants per meter
at harvest.
Tyfeter 0 = no UV-B, control; meter 1 = first meter under the UV-B
gradient irradiator.
IV-3 7
-------
Table' 22. Seedling data for Southern peas .
M
<^
I
U)
CD
Leaf (2)
Meter Fresh
0 14.3
1 10.2
2 13.6
3 11.6
4 11.1
5 12.3
6 12.8
7 11.2
8 9.8
Sx 1.09
Meter %
0
. . 1
2
3
4
5
6
7
8
Dry
1.626
1.338
1.697
1.470
1.429
1.570
1.614
1.521
1.333
0.117
Lf...
55
57 .
55
55
55
55
55
56
57
Stem(g) Root(s) Total Dry Weight
Fresh
14.2
10.7
14.6
11.8
12.1
13.3
13.4
11.6
% St.
38
35 .
37
36
37
37
37
36
36
9.2
1.12
% Rt.
7
8
8
9
8
8
8
8
7
Dry Fresh Dry Fresh
1.139 1.18 0.
0.834 1.03 0.
1.128 1.41 0.
0.956 1.17 0.
0.949 1.07 0.
1.065 1.18 0.
1.070 1.21 0.
0.977 0.98 0.
0.778 1.03 0.
0.096 0.99 0
Leaf Density
Area (cm2) (g/dm^)
558 0.282
460 0.282
616 0.279
560 0.267
522 0.274
550 0.285
572 0.280
522 0.294
446 0.300
224 29.3
191 21.9
254 29.6
229 24.3
203 24.8
224 26.8
247 24.4
203 23.8
211 20.0
.208 2.95
Root:
Shoot Ratio
0.081
0.088
0.090
0.095
0.086
0.085
0.092
0.081
0.100
Biomass
2.99
2.36 .
3.08
2.58
2.58
2.86
2.93
2.70
2.32
0.404
Sx 39.23 0.020 0.006
Cleans from 4 field beds, each with 9 meters and 7 to 19 plants/meter. Plants
were thinned 31 days after planting.
2Meter 0 = no UV-B, control; meter 1 = first meter under the TJV-B gradient irradiator,
-------
The most pronounced decreases were observed in the first meter receiving
1.55 UV-B leaf area was not reduced.
seu'
Leaf density and rootrshoot ratios were higher under UV-B enhancement
regimes. Slightly more biomass was partitioned into the leaves at the
expense of stems under UV-B enhancement. The estimated regression, equations
for leaf area and stem fresh weight under UV-B enhancement were 354.2 +5.72
x and 7.2 + 1.94 - .147X , where X = UV-B
' seu ' .
Significant reductions in the mean of the UV-B treated plants from
the mean of the control plants was found in Southern pea .stem fresh and dry
weight, root dry weight and total biomass (Table 23). In general, leaf area
was also lower. Southern pea fruit yield was also significantly reduced
(Table 24). The mean of the treated meters had significantly reduced num-
bers iof peas in the third and the final harvest and pea weight was significant-
ly less in the third and fourth and in total harvest. Other reductions were
evident, but often restricted to those meters receiving the higher levels of
UV-B
seu.
V. _'_F_lorunner' Peanuts '
A. Seedlings; Five to 8 seedlings per meter were removed 6 weeks after
planting, leaving 6 plants per meter to mature to harvest. Significant linear
regression relationships for decreasing leaf area, leaf, stem, root ant
total fresh and dry weights with increasing UV-B enhancement as the indepen-
dent variable were found (Table 25). The linear regression appears to fit
fairly well except meter 6. This means that after six weeks, any UV-B en-
hancement in the field tended to decrease1Florunner1peanut leaf area, leaf
fresh and dry weight, stem fresh and dry weight and total biomass (Table 26).
Biomass partitioning, leaf density and rootrshoot ratios were not strongly
IV- 39
-------
Table 23 . Plant Harvest data for Southern
i
_<^
o
Leaf
Meter
0
1
2
3
4
5
6
7
8
Area
174
167
170
163
132
147
127
106
156
Fresh
48
46
39
39
52
39
31
31
45
Dry
6. .9
7.3
6.4
6.6
6.3
6.4
5.5
5.1
6.6
Stem
Fresh*^
93
72
68
67
79
66
56
52
69
Dry*
17.5
13.5
12.8
12.8
12.0
12.9
11.1
9.8
11.8
Root
Fresh
10.8
'10.2
6.8
6.8
8.8
7.5
6.5
6.8
7.1
Dry*
1.8
1.4
1.6
1.5
1.4
1.8
1.7
1.5
1.4
Bio-
mass*
26
22
21
21
20
21
18
16
20
R:S
Ratio
.079
.070
.084
.080
.082
-.095
.105
.109
.081
Leaf
Dens.
.0108
.0125
.0147
.0141
.0133
.0140
.0150
.0144
.0133
S X
20.4 .7.28 0.582
9.49
0.95
1.92 0.132
1.49
.0072
.0007
Means from 4 field beds, each with 9 meters and 6 plants per meter at harvest.
Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient irradiator.
indicates average of all UV-B treatments was significantly less than the control.
-------
Table 24 Southern pea fruit yield .
Harvest 1 Harvest 2 Harvest 3 Harvest 4 Harvest 5 Total
Meter
0
1
2
3
4
5
6
7
8
No
15.8
7.3
15.3
9.0
10.0
12.3
11.3
10.3
8.5
Wt
84
37
67
46
50
62
55
54
43
Ave
5.3
5.1
4.4
5.1
5.0
5.0
4.9
5.2
5.1
No
14.2
18.0
19.8
13.0
16.3
17.5
21.8
17..0
13.5
Wt
67
88
91
68
75
81
98
77
64
Ave
4.7
4.9
4.6
5.2
4.6
4.6
4.5
4.5
4.8
No* 3
27.8
17.5
14.3
18.0
12.5
24.0
15.5
15.5
21.8
Wt*
122
81
60
80
.52
86
59
53
95
Ave*
4.4
4.6
4.2
4.4
4.2
3.6
3.8
3.4
4.4
No
19.8
14.5
10.5
16.5
13.0
14.0
9.0
11.0
19.8
Wt*
82
60
39
65
50
55
28
38
70
Ave
4.1
4.1
3.7
3.9
3.8
3.9
3.1
3.4
3.5
No
19.8
23.3
13.7
17.7
20.7
8.0
8.3
11.0
19.0
Wt
88
98
57
87
77
28 .
30
36
77
Ave
4.4
4.2
4.2
4.9
3.7
3.5
3.6
3.3
4.1
No*
88.0
74.8
70.0
69.8.
67.3
73.8
63.8
62.0
77.8
Wt*
402
340
301
324
285
303
264
249
329
Ave*
5.6
4.5
4.0
4.6
4.2
4.1
4.1
4.0
4.2
s- 3.68 18,30 2.71 12.64 2.74 11.6 3.57 13.66 4.06 18.32 6.12 26.0
x
Means from 4 field beds, each with 9 meters and 6 plants per meter at harvest.
2
Meter 0 = no UV-B, control; meter; meter 1 = first meter under the UV-B gradient irradiator.
3 '
* indicates average of all UV-B treatments was significantly less than the control.
-------
Table 25. Equations for linear responses of thinned Florunner
peanuts to UV-B enhancement under the field gradient
irradiator
Response . Equation
Leaf Area 436.90 - 13.81X
Leaf Fresh Weight 8.6573 - 0.2427X
Leaf Dry Weight 1.5728 - 0.0476X
Stem Fresh Weight 8.2592 - 0.2310X
Stem Dry Weight 1.1813 - 0.0333X
Total Fresh Weight 19.750 - 0.5455X
Total Dry Weight 3.3366 - 0.0948X
IV-42
-------
Table 26. Seedling data for Florunner peanuts
4^
U)
Meter
0
1
2
3
4
5
6
7
8
Si
Leaf (g)
Fresh Dry
9.3
6.4
6.7
6.4
7.6
10.1
7.3
7.6
7.6
0.83
Meter
. . 0
1
2
3
4
5
6
7
8
1.591
1.077
1.159
1.221
1.274
1.712
1.355
1.442
1.389
0.122
% Lf . %
47
45
46
48
47
46
46
46
48
St,
36
36
35
36
37
36
34
34
36
Stem (g)
Fresh
8.9
5.9
6.0
6.4
7.4
9.5
7.3
7.0
7.1
0.851
. % Rt
17
19
19
16
16
18
20
20
16
Dry
1.206
0.846
0.877
0.900
1.004
1.313
1.020
1.094
1.025
0.100
Leaf
Area
432
298
311
316-
388
491
370
373
381
Root (g)
Fresh
3
2
2
1
2
3
2
2
2
0
(cm
.1 0
.0 0
.4 0
.9 0
.1 0
.3 0
.8 0
.8 0
.4 0
.307 0
Dry
.591
.446
.482
.404
.416
.659
.585
.617
.478
.059
Density
) (g/dm2)
0.401.
0.398
0.383
0.419
0.392
0.354
0.381
0.428
0.384
Total Dry Weight
Fresh Biomass
21.4 3
14.4 2
14.7 2
14.7 2
17.2 2
22.9 3
17.4 2
17.5 3
17.0 2
1.90 0
.39
.37
.52
.53
.70
.68
.96
.15
.89
.263
Root
Shoot Ratio
0.
0.
0.
0.
0.
0.
0.
0.
0.
213
244
238
214
206
232
276
282
210
40.72
0.033
0.023
Means from 4 field beds, each with 0 meters and 5-8 plants/meter. Plants
were thinned 40 days after planting. .
Teeter 0 = no UV-B control; meter 1 = first meter under the UV-B gradient irradiator.
-------
affected at this time.
B. Harvest: At harvest, significant linear regression relationships
were found for leaf fresh and dry weight and leaf area and in all cases the
responses increased with .UV-B enhancement. The estimated equations are
12.43 + 0.919X, 3.34 + 0.190X and 294.45 + 142.870X for leaf fresh weight,
dry weight and leaf area, respectively. Since only the first plant in each
meter was measured for leaf area, this parameter and leaf specific thick-
ness are based on 4 rather than 24 plants. In general, the peanuts re-
ceiving the 1.55 UV-B showed higher leaf fresh and dry weight, higher stem
fresh and dry xveight but a reduction in root fresh and dry weight and the
number of larger peanuts. These plants were-.also taller, with a greater
biomass and leaf area but a much lower root to shoot ratio than the control plants
(Table 27). Decreasing the dose of UV-B irradiation resulted in the opposite
effects.
VI. 'Star Bonnet' Rice
Rice was thinned 41 days after planting to 10 plants per meter. In
averaging all UV-B treatments it was found that the root dry weight was sign-
ificantly less for plants from treated than the control meters. Leaf, root
and biomass dry weight were all lower for seedlings from meters receiving 1.55
to .28 UV-B (between meter 1 to 5) but parameters measured in olants 'with
seu
lesser UV-B were similar to the controls. Leaf densitv was slightly
seu " J
higher at the lower UV-B levels .21 to .09 UV-B (meters 6 to 8). Bio-
mass tended to be partitioned more into the leaves and stems than the roots
for all UV-B treated plants (Table 28) . '->
f
At harvest of mature plants, significant linear relationships were
*
found for 6 of the parameters measured on the tillers (Table 29). Reductions
in spike fresh and dry weight were found under the 1.55 UV-B of 1.55 to
seu
0.61 (meter 1 and 2). Spike maturity was delayed under UV-B 1.55 (meter 1).
.o C U
IV-44
-------
Table 27. Harvest data for Florunner peanut plants
1
2
Meter
0
1
2
3
4
5
6
7
8
sx
Leaf
Fresh
19.6
23.7
17.1
21.6
14.4
15.8
12.9
18.9
12.9
2.53
Meter
0
1
2
3
4
5
6
7
8
00
Dry
4. a 03
5.578
4.560
5.264
3.332
3.897
3.290
4.950
3.637
0.608
Leaf
Area
986
2211
1367
701
750
891
512
1094
697
Stem
Fresh
45.9
51.9
42.9
48.2
39.9
43.4
43.0
56.6
40.2
6.04
Density
(cm2) (cm2)
.436
.432
.489
.426
.445
.480
.399
.522
. .454.
00
Dry
9.98
11.25
9.73
10.14
8.38
9.45
9.33
13.24
9.04
1.42
Root
Shoot
Ratio
.088
.060
.099
.107
.120
.081
.087
.084
-.096-
Root
Fresh
4.7
4.2
4.7
5.3
3.9
4.2
4.3
5.1
4.1
0.562
Big
No.
50.5
44.8
44.1
47.5
39.8
45.5
45.3
49.9
38.6"
00
Dry
1.232
1.088
1.275
1.248
1.225
1.028
1.018
1.324
1.049
0.178
Peanuts
Wt.(g)
51.22
46.92
50.12
50.49
40.81
46.10
47.95
54.70
43.67
Total
Frech(g)
70.2
79.8
64.7
75.1
58.2
63.4
60.2
80.6
57.2
Pop
No.
3.5
3.3
4.0
4.1
3.6
3.1
2.9
2.9
4.1
Dry Weight
Biomass(s)
16.01
17.92
15.57
16.65
12.94
14.37
. 13.55
19.52
13.72
2.06
Peanuts
wt.GO
1.921
2.500
2.942
2.367
2.058
1.800
1.642
1.800
2.253
%
Lf.
30
31
29
32
26
27
23
25
26.
lit.
36.7
49.6
36.6
37.7
36.8
37.3
35.0
39.2
37.9
7 '
to
St..
62
63
63
61
65
66
69
68
66
(cm.)
.%"
Rt.
8
6
8
7
9
7
8
7
8
f
sx 381.0 .000455 .0163 3.62 4.88 0.829 0.551 2.22
^Means from 4 field beds, each with 9 meters and 6 plants per meter at harvest.
2Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient irradiator..
-------
Table '28. Seedling data* for rice plants'
Meter2
0
1
2
3
4
5
6
7
Leaf(s)
Fresh
35.9
30.7
32.5
36.7
29.2
28.4
40.8
36.4
Dry
9.09
7.41
8.06
8.50
6.86
7.13
10.63
9.71
Root(g)
Fresh
9.65
5.93
8.55
9.15
6.15
6.60
8.37
7.96
Dry3
2.51
1.54
2.15
2.30
1.54
1.63
2.39
2.25
Total
Fresh(s)
45.5
36.6
41.0
45.8
35.3
35.0
49.1
44.3
Dry Weight
Biomass (g)
11.60
8.95
10.21
10.80
8.40
8.76
13.02
11.96
32.9 8.44 6.16 . 1.80 39.0 10.24
4.72 0.98 11.06 2.22 15.09 3.01
Leaf Density
Meter' 7, Lf. % Rt. Area g/dm
0 78 22 83 0.117
1 83 17 67 0.115
2
3
4
5
6
1
8
79
79
81
81
82
81
82
21
21
19
19
18
19
18
75
91
69
60
82
77
68
0
0
0
0
0
0
0
.114
.100
.108
.120
.132
.132
.133
sx 11.71 0 .131
from 4 field beds, each with 9 meters and 5-26 plants/meter. Plants were
thinned 42 days after planting.
^Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient irradiator,
^Indicates mean of UV-B treatments was significantly less than the control.
-------
Table 29. Rice tiller data showing significant relationships among the UV-B
treatments and their corresponding regression equations .
Response
Spike Dry Weight 2.78 - 0.0773X
Spike Stage 3.48 - 0.1834X
Spike Length 21.44 + 0.2140X
Flag Fresh Weight 2.64 + 0.2157X
Flag Dry Weight 0.14 + 0.0065X
Flag Length 20.84 + 0.6437X
X = UV-B enhancement in solar equivalent units (seu).
IV-A 7
-------
and progressively increased in the next two meters of less exposure. The
.'most marked response was the increase in the number of leaves per tiller
under UV-B enhancement.
Flag leaf length, area, fresh and dry weight were increased under UV-B.
of 1.55 to .34 (meter 1 to 3) but fresh and dry weight of the spike were
less than the controls (Table 30). Spike length, however, remained fairly
constant. Spike fresh and dry weight and root dry weight ware reduced in
the meter receiving 1.55 UV-B and spike maturity was delayed in this
meter also. . .
On a whole plant basis, rice in the UV-B treated meters tended to de-
crease in biomass and stem fresh and dry weight (Table 31). The number of
fruiting and vegetative tillers was unaltered from the control meters but the
number of tillers was somewhat reduced, at least in the 1.55 UV-B meters.
seu
The average roof.shoot ratio in treated meters was significantly less than
that in the control meters. Significant relationships within the UV-B treated
meters were found for 5 parameters and these are given in Table 32.
Height growth of the'Star Bonnet' Rice was exponential until the 9th
week after planting when is slowed tremendously (Table 33). A growth curve
equation was computed for each meter and fit the data well (Table 34).
VII. Yellow-cirooked-neck squash
A. Seedlings: Five to seven seedlings per meter were removed 3 weeks
after planting, leaving 6 plants per meter to mature. A total of 11 respon-
ses were measured on the removed seedlings and means are given on a per plant
' >
basis with the standard error of each mean (Table 35). In averaging all UV-R-
treatments, there was a significant difference in reduction between all UV-B
treated plots and the control plot at the 10% level for leaf fresh and dry
weight, root fresh and dry weight and total biomass. The rootrshoot ratio
-------
Table 30. Harvest data for rice tillers by plant
f
Leaf (g)
Stem (g)
Spike
2
Meter
0
1
2
3
4
5
6
7
8
Fresh
2.38
2.75
2.54
2.24
1.86
2.81
2.07
2.07
2.04
Dry
1.13
1.15
1.03
1.C8
1.01
1.31
0.94
0.95
1.13
Fresh
9.57
10.51
9.29
9.43
8.95
' 12.45
8.11
8.03
9.27
Dry
2.73
2.99
2.47
2.62
2.58
3.82
2.25
2.21
2.68
Fresh (g)
3.97
3.13
3.72
3.69
3.44
4.80
3.57
3.64
3.61
Dry (g)
2.54
1.74
2.25
2.43
2.41
3.11 '
2.35
2.35
2.45
3
Stage
2.8
1.3
2.1
2.5
2.9
2.6
2.7
3.1
3.1
PI. Ht. to
Spike (cm)
71
66
64
71
70
71
64
67
73 '
# Lvs./
Tiller
4.4
6.2
6.0
6.1
6.1
6.4
6.2
6.2
6.6
0.193 0.071
1.21 0.316
0.459
0.300
0.322
3.38
0.280
Area (cm )
Flag Leaf
Density (g/dm )
Meter
0
1
2
3
4
5
6
7
8
All Lvs.
148
157
158
154
11 G
171
124
126
138
Flag
24
33
33
30
23
27
. 26
22
22
Length (cm) .
22.5
27.6
25.7
25.8
24.8
22.7
23.2
21.5
22.0
Fresh (g)
.030
.046
.050
.037
.031
.039
. .033
.035
.024
Dry (g)
.0159
.0215 .
.0181
.0177
.0162
.0162
.0152
.0162
.0146
Spike
. Length (cm)
22.9
23.9
22.6
23.7
22.5
22.4
22.0
20.9
22.2
Leaf
0.76
0.79
0.64
0.70
0.85
0.77
0.76
0.95
0.85
Flag
0.76
0.74
0.55
0.68
0.73
0.73
0.60
0.73
0.69
10.5
2.14
0.87
0..65
0.020
0.56
0.0009 0.0010
"Means from 4 field beds, each with 9 meters and all the tillers of each of the first 3 plants at the time
?of harvest. . .
"Meter 0 = no UV-B, control, meter. 1 = fritst meter under the UV-B gradient irradiator.
State of maturity; 0 = all of spike green; 2 = .%, 3 = ^, 4 = 3/4 and 5 = all of spike brown.
-------
Table 31; Whole plant harvest data for rice."
01
c
Meter
0
1
2
3
4
5
6
7
8
ss
Meter
0
1
2
3
4
5
6
7
8
S X
No.
Fruit
8.9
7.6
8.8
8.8
7.3
8.7
8.9
9.1
7.6
0.641
Spike
Fresh
37
24
33
34
28
33
35
34
28
2.89
of Tillers
Veg
1.8
1.2
2.1
1.0
0.8
1.9
2.1
1.7
1.4
0.315
Wt(g)
Dry
24.1
14.0
20.6
23.1
18.5
21.6
24.2
22.4
17.6
1.83
Total
10.7
8.8
10.9
9.9
8.1
10.6
11.0
10.8
9.0
0.80
Root Wt
Fresh
48
39
50
48
44
42
44
58
62
6.77
Leaf Wt. - (g)
Fresh
38
36
45
34
28
35
32
34
29
4.53
.(g)
Dry
15.8
11.6
14.6
15.5
14.1
12:8
15.0
19.0
19.8
2.14
Dry
13.8
11.6
13.1 -
13.5
11.1
13.3
13.6
13.3
1.1.6
1.12
Bio-
mass
84
62
76
78
68
76
81
83
76
6.93
Stem Wt. (g)
Fresh Dry
105 30.1
87 24.2
101 27.5
95 26.2
81 23.7
101 28.0
1.00 28 . 4
102 27.7
87 26.6
9.9 2.67
R:S
Ratio*3
3. . 545
0.013
1.218
0.734
0.698
0.560
0.629
0.927
1.129
0.193
3.2
1.7
2.7
3.2
3.0
3.2
3.6
3.2
2.9
0.229
Means from 4 field beds, each with 9,meters and 6 plants per meter at harvest.
Meter 0= no UV-B, control; meter 1= first meter under the UV-B gradient irradiator.
3* indicates average of all UV-B treatments was significantly less than the control,
-------
Table 32 . Star Bonnet rice whole plant responses showing
significant relationships among the UV-B treatments
and their corresponding regression equations.
J Response Equation
Leaf Fresh Weight 28.269 + 1.181X
Root Dry Weight
18.442 - 0.614X
Spike Fresh Weight 22.738 + 4.151X - 0.376X
Spike Dry Weight
13.700 + 3.449X - 9.324X
Spike Stage
2.383 + 0.398X - 0.044X
X = UV-B enhancement in solar equivalent units (seu).
IV-51
-------
,Table 33. Mean gfcar Bonnet rice
Meter Number
Week
2
3
4
5
6
7
8
9
10
11
.12
f!3
14
15
16
02
07
12
19
29
55
67
82
92
94
95
103
111
112
112
112
1
08
12
20
29
56
69
86
96
97
98
99
107
109
109
109
2.
08
12
20
30
57
70
88
99
99
99
103
113
113
113
113
3
08
13
21
31
57
71
87
97
98
100
105
113
114
114
114
4
08
12
18
27
55
69
86
97
100
100
103
111
112
113
113
5
07
10
18
26
55
68
87
99
101
102
103
110
111
111
111
6
08
11
20
30
58
71
89
99
102
102
105
113
113
114
114
7
07
12
21
30
57
70
87
99
102
103
106
113
114
114
114
8
08
12
21
27
55
68
86
95
97
97
98
106
107
107
106
Each number is the mean of 40 plants, 10 per meter replicated in 4 field
7:beds.
2 '
Meter 0 = no UV-B control; meter 1 = first meter under the UV-B gradient
.irradiator.
IV-5 2
-------
Table 34. Star Bonnet Rice growth curve equation and
regression coefficients for each meter .
Growth Curve Equation Regression Coefficients
Height = Ae B/t
where t = time in weeks
Meter
0
1
2
3
4
5
6
7
8
A
19.72
18.80
19.65
19.63
20.01
19.80
19.79
19.93
18.28
B
7.87
7.34
7.49
7.46
7.81
7.73
7.48
7.56
7.24
IV-53
-------
faille 35.
Meter2
0
1
2
3
4
5
6
7
8
SK
Seedling data for squash
Leaf (g) Stem(g)
Fresh3
17.8
13.9
12.1
13,1
14.1
13.9
13.2
13.2
10.9
2.58
Dry3
2.921
2.293
2.126
2.206
2.395
2.262
2.290
2.215
1.993
0.385
Fresh Dry
69
54
50
53
55
53
53
50
42
10
.9
.3
.8
.0
.8
.8
.4
.1
.0
3.859
2.888
2.964
3.090
2.886
2.804
3.108
2.953
2.533
.28 0.542
Root(g)
Fresh-5 Dry3
3.1
2.2
2.5
2.5
2.3
2.3
2.5
2.5
2.5
0.438
0.283
0.355
0.358
0.303
0.338
0.383
0.320
0.360
Total3
Dry Weight3
Fresh(tO Biomass (g)
90.8
70.4
65.4
68.6
72.2
70.0
69.1
65.8
55.4 '
0.366 0.048
Leaf Density
Meter
0
1
2
. 3
4
5
6
7
8
s-
% Lf .
40
42
39
39
43
42
39
40
41
% St.
54
53
54
55
52
52 .
54
54
52
% Rt.
6
5
7
6
5
6
7
6
7
Area g/d
986 0".
792 0.
680 0.
706 0.
754 0.
755 0.
742 0.
736 0.
622 0.
146.9 0.
m^
292
312
330
317
379
316
354
340
352
0003
Root
Shoot
Ratio
0.072
0.058
0.079
0.080
0.075
0.107
0.088
0.069
0.085 .
0.1620
Ht.(cm.)
24.9
24.7
22.3
21.9
21.7
21.9
22.2
23.2
20.6
1.43
7
5
5
5
5
5
5
5
4
0
.22
.46
.45
.65
.58
.40
.78
.49
.89
.959
'
Means from 4 field beds, each with 9 meters and 5-7 plants/meter. Plants were
thinned 24 days after planting.
2Meter 0=no UV-B control; meter l=first meter under the UV-B gradient irradiator.
^Indicates mean of UV-B treatments significantly (10% level) less then control.
-------
was increased for all UV-B treated plants. Biomass partitioning was not
significantly altered by enhanced UV-B radiation.
B. Harvest: Frost damage to the squash plants forced early harvest.
In all meters, there was a significant reduction by the UV-B dose in relation
to the control for leaf, fruit and root fresh weight, root dry weight, and
numbers of fruit. Stem and total plant fresh and dry weights were reduced
under all levels of UV-B enhancement. A greater number of fruit and total
fruit biomass was found on control plants than on UV-B treated ones. An
occassional large fruit in the meter gradient 4 and 5 resulted in a larger
weight/fruit number. The significantly greater number of fruit in the
control meter may indicate a delay in flowering under enhanced UV-B rad-
iation. The rootrshoot ratio was reduced under the highest UV-B enhancement
but increased under others (Table 36). Biomass partitioning was not sign-
ificantly altered by enhanced UV-B radiation.
VIII. Mustard
At harvest the leaf fresh and dry weight, total biomass and leaf density
of the control plants were all significantly greater than the mean of the
UV-B treated meters (Table 37). Total fresh weight was lower under the UV-B
radiation regimes also. Root fresh and dry weight and the total number of
leaves showed the most reduction under UV-B , of 3.1 to 1.2 (meter 1 to 2).
. r,t?.\i s
Plants receiveing UV-B irradiation at lesser flux level were similar to the
control for these 3 parameters. Leaf area was drastically reduced at UV-B
seu
2
of 3.1 (meter 1) from 1330 to 443cm . Biomass partitioning was not
altered by UV-B enhancement. Significant linear and quadratic relationships
were observed for 5 parameters (Table 38).
IX. 'Red Globe' Radish
Leaf fresh and dry weight and leaf area were all significantly greater
under UV-B treatment than the control radish plants. However, in the first
-------
36. Harvest data for squash1;
<
Ul
2
Meter
0
1
2
3
4
5
6
7
8
Leaf.,
Fresh"'
58.6
43.9
39.7
45.1
47.0
31.1
39.7
36.0
32.9
00
Dry
7.
5.
5.
6.
6.
4.
5.
5.
4.
419
921
307
392
282
769
673
423
839
Stem
Fresh
25.1
19.7
17.7
18.9
19.8
16.2
19.5
17.6
16.0
00
Dry
1.
1.
1.
1.
1.
1.
1.
1.
1,
,733
,352
,212
.331
,351
,065
.380
.254
.115
Root
00
Fresh^DryS
7.1
5.6
5.8
6.1
6.1
5.0
5.6
6.0
5.2
0.952
0.702
0.715
0.863
0.805
0.635
0.801
0.853
0.695
Total
Fresh (g)
90.8
69.6
63.2
70.1
72.9
52.3
64.8
59.6
54.1
Dry Weight
Biomass
10
7
7
8
8
6
7
7
6
.10
.98
.23
.59
.44
.47
.85
.53
.65
7.65 0.961
3.27 0.232
0.475 0.073
1.25
Meter %
0 .
1
2
3
4
5
.6
7
8
Lf.
74
74
73
75
74
74
72
72
73
% St.
17
17
17
15
16
16
18
17
17
% Rt.
9
9
10
10
10
10
10
11
10
Root
Shoot
Ratio
0.127
0 . 100
0 .134
.135
0 .120
0 .130
0 .135
0 .137
0 .130
Fruit
No.-1
1.17
0.75
0.50
0.75
0.67
0.21
0.63
0.58
0.38
Wt.(g)3
- 8.95
2.88
1.41
2.21
7.73
4.09
2.06
0.91 .
1.12 .
Wt. /Fruit
5.23
3.64
2.58
3.31
3.07
9.60
1.84
1.03
1.72
00
Sx 0.016 0.224 2.263 2.43
^Meaas from 4 field beds, each with 0 meters 6 plants per meter at harvest.
Tleter 0 = no UV-B,control; meter 1 = first meter under the UV-B gradient irradiator.
3
Indicates mean of UV-B enhancement meters was significantly less then the control.
-------
Table 37. Harvest data for mustards
M
f
Ln
Meter2
0
1
2
3
4
5
6
7
8
Leaf(g)
Fresh-*
63.6
36.5
51.4
57.1
51.1
52.1
52.8
57.8
49.5
Dry3
4.837
2.741
3.934
4.405
4.271
4.008
3.946
4.229
3.835
Root(s)
Fresh
6.5
3.8
5.8
6.2
6.6
6.0
5.8
6.3
4.8
Dry
0.812
0.430
0.702
0.779
0.685
0.694
0.630
0.728
0.605
Total (g)
Fresh
70.1
40.3
57.2
63.3
56.7
58.1
58.6
64.1
54.3
Dry Weight
Biomass (g)
5.65
3.17
4.64
5.18
4.96
4.70
4.57
4.96
4.44
5.64 0.400
0.592 0.076
0.465
Meter
0
1
2
3
4
5
6
7
8
%Lf.
86
86
85
85
86
85
86
85
86
% Rt.
14
14
15
15
14
15
14
15
14
Leaf
Area (cm2)
1330
443
1355
1348
1253
1155
1393
1175
1047
Density3
S/dmz
0,370
0.310
0.330
0.340
0.360
0.320
0.320
0.310
0.340
Root
Shoot
Ratio
0.172
0.176
0.182
0.179
0.184
0.178
0.181
0.186
0.168
No. of
Leaves
8.25
5.83
7.67
8.17
8.00
7.58
8.33
8.08
8.42
184.8
0.0001
0.011
0.50
Cleans from 4 field beds, each with 9 meters and 20 plants per meter at harvest.
%eter 0 = no UV-B control; meter 1 = first meter under the UV-B gradient irradiator.
^Indicates the mean UV-B enhancement meters were significantly less than the control.
-------
Table . 38. Regression equations for mustard to
UV-B enhancement under the field grad-
ient irradiator.
Response
Leaf Dry Weight
Number of Leaves
Leaf Area
Root Fresh Weight
RLomass
Equation
3.07 + 0.49X - 0.049X2
8.83 - 0.209X
571.3 + 304.7X - 28.7X2
3.69 + 0.954X - 0.0883X2
3.50 + 0.609X - 0.0595X2
IV-58
-------
meter which received 3.1 UV-B The root fresh weight was 3.34g vs. 5.05g
seu
for the control. The number of leaves remained constant and there were no
significant differences in leaf density.(Table 39).
Discussion
Other studies on the effects of UV-B radiation on plants have shown that
net carbon exchange was reduced (see section 5). This would result in de-
creased biomass production. The present field work demonstrated that biomass
reductions are not equally proportioned between shoots and roots and organs
on the shoots, resulting in very different biomass allocation patterns.
The percent of plant dry weight found in leaves was in general, increased at
the expense of stems (stunting) and sometimes root dry weight. Because root
dry weight proportions may decrease it appears that not only photosynthesis
but phloem translocation of photosynthate may be impaired by increases in
UV-B irradiance levels. Thus, the longer it takes a crop to produce a martet-
able product, the more pronounced the deleterious effects of UV-B radiation
could become. Translocation to fruits would also be expected to be impaired
resulting in lower yields. In addition, leaf expansion is decreased as the
plants become autotrophic from seed-stored organic and mineral reserves. The
implications for perennial plants, especially evergreens, is obvious, as
these effects may accumulate and become magnified.
Of the underground root and tuber crops grown, only the radishes had
reduced root biomass under' 3.1 UV-B . These radishes iiad increased leaf
seu
fresh and dry weights over the controls but decreased root weight, possibly
again indicating an impaired translocation from shoot to root. However, in
all the other levels of UV-B treatment the radishes not only had greater
leaf biomass, but root biomass as well. Increased leaf weights tfere a re-
TV- 5 9
-------
Table 39. Harvest data for radishes1,
Meter2
0
1
2
3
4
5
6
7
8
Leaf
Fresh3
2.6
3.4
4.4
4.4
4.7
5.1
4.5
4.0
2.9
00 ,
Dry3
0.311
0.338
0.434
0.450
0.433
0.471
0.434
0.421
0.314
Root
Fresh (R)
5.1
3.3
7.1
8.7
7.8
10.6
8.2
9.4
5.1
Total
Fresh
7.7
6.7
11.5
13.1
12.5
15.7
12.7
13.4
8.0
Leaf
Area
(cm2)
72
90
106
107
121
132
109
87
87
3
0
0
0
0
0
0
0
0
0
Density
g/dm
.43
.38
.41
.42
.36
.36
.40
.48
.36
No. of
Leaves
7.15
8.15
7.45
7.25
8.10
8.00
7.50
7.70
8.35
0.526 0.042
1.36
13.75
0.52
Means from 4 field beds, each with 0 meters and 50 plants/met.er
at harvest.
2Meter 0 = no UV-B, control; meter 1 = first meter under the UV-B gradient
irradiator.
Indicates mean of UV-B treated meters was significantly greater then the control.
-------
flection of a greater number of leaves and leaf area but lower leaf densities.
'Irish'potatoes under all UV-B had increases in number of fruit and total
seu
weight of the smaller creamer grade size fruits. Overall yields as rated
by total weight of fruit from UV-B treatment were less than the controls.
This was primarily due to potatoes of larger sizes.
For peanuts, as with the potatoes, there was an inverse relationship
/
for above ground bioruass and below ground biomass at the higher (.1.55 UV-B . )
. seu
UV-B irradiance levels. Leaf and stern weights and leaf area were all higher
than controls at these levels but with loxjer root weight, peanut number and
yield. The smaller peanuts from UV-B treatment weighted more than equiv-
alent size fruits from the controls. Correspondingly the rootrshoot ratios
.was also reduced under the higher UV-B enhancement level.
Mustards were the only crop grown for commercial harvest of the leaf.
All parameters measured on the UV-B treated plants were lower than the con-
trol but the reductions were proportional since biomass partitioning was
not altered. The number of leaves and leaf area in the 3.1 UV-B meter was
seu
drastically reduced. Even the smaller reductions in fresh weight of the
other UV-B treated plants may have serious implications for commercial pro-
duction of this crop.
That detrimental UV-B effects are accumulative was shown in the flower-
ing and fruiting of tomatoes. The first panicle of flowers was initiated
before transplanting the second shortly after transplanting into the field
beds under the UV-B gradient irradiator. Flowering on the third hand was
earlier on control plants. The dalay in flowering of treated plants was
more evident as reflected in the harvest data. Tomato weight was lowered in
the first harvest when only mature green tomatoes were harvested, but in
the second harvest the yield differences between control and UV-B treated
meters was enen more pronounced on a weight basis. Interestingly, the weight
IV- 61
-------
of cull and immature fruit in the second harvest was lower than the controls
.., 01 TTW T. treated meters. This indicates not only weight of tomatoes
in the .04 uvb
seu
was reduced, but also the number of fruit.
Height reduction was the most obvious effect of UV-B radiation on corn
as both main and sucker stalks were reduced. In addition leaf area, leaf
weights, and number of silks on both main and sucker stalks and root weights.
were reduced, especially at the higher LTV-3 .levels. However, these reductions
in vegetative parameters x^ere not reflected in the final yield of corn. The
other monocot (rice) did not have the same paterns of response as corn to en-
hanced UV-B radiation. Height and fruit weights were reduced, but leaf area
was increased both for total leaves and for the flag leaf. The total num-
ber of leaves was also increased. If translocation was reduced, this could
partially account for the larger leaf biomass in UV-B treated plants and in
spike weights. Spike maturity was also delayed. This could be due to an ef-
fect on bolting but data was not taken that would allow an unequivical dis-
cernment of this parameter on rice.
Thinning data was taken for Southern peas, peanuts, rice and squash.
All species showed decreases in leaf, stem and root weights and, except for
peas, reduced leaf area from enhanced UV-B radiation at this earlier
time of measurement . Leaf density was also consistently increased by UV-B
radiation, except in peanuts. Although reduced root:shoot ratios were found
in mature plants, only the UV-B treated seedling rice had reduced root:shoot
ratios while the ratio was increased for young squash and pea plants. Since
the indications are that leaves are affected first by UV-B radiation and the
effects on roots are manifest by a reduction in translocations of photosynth-
ates, one would expect the ratio to increase in seedlings and then decrease
as roots may become increasingly affected. The close anatomical relationship
TV--6 2
-------
of roots to seed storage reserves could be preventing an earlier effect on.
root development. Some alterations in biomass partitioning were beginning
to become evident on rice seedlings since both had increases in leaf weight
at the seedling harvest stage.
-------
ment combinations (Table 1) throughout the course of the experiment. These
16 treatments consisted of 4 flux levels of PAR and UV-B irradiances in all
possible combinations. UV-B radiation was supplied by pre-burnt Westinghouse
FS 40 sunlamps. A fixture containing 2 filtered lamps each was suspended
above the plants in each treatment. This radiation was filtered on all lamps
by plastic films of either Mylar S (complete absorption of radiation below
320 nm) or 3 mil cellulose acetate (transmission of UV-B to 292 nm). Due to
solarization, filters were routinely changed every three days to maintain
transmission of the desired spectral qualities. The 4 UV-B irradiances were
obtained by matching each lamp with the proper combination of filters and by
adjusting the lamp distance above the plants. Thereafter, the distance
between the lamps and the plants was maintained by raising the lamps as the
plants grew.
UV-B irradiances employed were equivalent to zero (mylar control) 1/2,
2
1, and 2 solar equivalents. The lamps were programmed with a timer for six
house irradiance during the middle of the natural photoperiod, between 10 am
and 4 pm. The 4 PAR levels were obtained by using a combination of commer-
cially available neutral density shading materials. These were positioned
over a frame constructed above the lamps in each treatment, covering all four
sides and the top. Plastic films of Mylar S separated each treatment to
prevent any UV-B scatter between treatments. The 4 shade levels used in
the experiment were 0 (unshaded), 33, 55, and 88% shading. Due to the lamp
configuration and overhead flowing water used to minimize the effects of
Lamps were illuminated for 100 hours prior to use to insure uniformity of
UV-B irradiance throughout the course of the experiment. Previous studies
have shoxm that lamp aging becomes somewhat linear after 100 hours of juse,
with a change of less than 5% total irradiance from approximately 100 to
600 hours of a neutral density characteristic (see methods .in Section I).
2
UV-B enhancement in solar equivalent units (seu).
V-4
-------
Table 1. Optronics reading for PAR/UV-B irradiance study Sept. 6 thru
Oct. 6, 1977. One 2 lamp fixture/treatment.
Treatment
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Optronics
Reading
4.6
6.2
6.2
2.5
-
2.5
T.
2.5
6.2
6.2
4.6
4.6
4.6
2.5
-.
UV-B Enhancement
xl
x2
x2
^
Mylar
^
Mylar
xh
x2
x2
xl
xl
xl
*k
Mylar
Mylar
Z2(cm)
38.0
41.0
33.5
60.0
50.0
60.5
50.0
69.0
36.0
34.0
40.0
40.5
38.0
72.0
50.0
50.0
% Shade3
unshaded
unshaded
33
unshaded
unshaded
33
33
55
88
55
88
33
55
88
55
88
UV-B Enhancement in solar equivalent units (seu)
2
Z measured from bottom of lamp to plant ht.
Shade levels obtained by neutral density screening 33%, 552 and 88%.
Average maximum daily unshaded irradiance = 1600 yEm sec PAR.
V-5
-------
shadows, the unshaded or full sun irradiance was somewhat lower than field .
levels, but higher than normal greenhouse irradiances. The maximum daily
photon flux density measured at the top of the plants was approximately
-2 -1
1600 yE m sec PAR. Therefore, the corresponding maximum daily PAR flux
-2 -1
under each shade treatment would be 1600, 1408, 880, and 528 pE m sec ,
N
respectively.
Leaf temperatures remained at ambient air temperature (ฑ3ฐC) in all 16
treatments.
Gas Exchange and Growth Measurements
For soybean, net carbon exchange (NCE), transpiration, and dark respira-
tion were measured at two different physiological ages on single, attached
leaves using a cuvette similar to that described by Patterson et^ jil_. (1977).
CO. was measured in an open system using a Beckman 215B infrared gas analyzer
in a differential mode. Water vapor concentrations were monitored with a
Cambridge Systems EG & G Model 880 Dewpoint Hygrometer. All gas exchange
measurements were done at a leaf temperature of 30ฐC, ambient C09 concentra-
tions of 320 ul/1 and a vapor pressure deficit of 10 mb.
Light was supplied by a General Electric cool beam incandescent lamp,
filtered through water. Irradiance to the leaf was varied by placing a series
of neutral density filters between the light source and the cuvette. Leaves
2 -1
were exposed to irradiances of 1300, 840, 480, and 170 uE m sec PAR. At
each irradiance, CO and water vapor fluxes were continuously monitored
until equilibration. After each series of light response measurements, dark
respiration rates were measured. Photon flux densities in the PAR region
were measured at the leaf surface with a Lambda Instruments LI-190S Quantum
t
Sensor.
V-6
-------
Diffusive resistances to water vapor were calculated following conven-
tional resistance analysis (Gaastra, 1959). Resistances to CC>2 were calculated
according to Nobel (1977). These resistances were related to one another in
the following manner:
2 gas _ air stomata
JH,O " ~ฃS "here "H,O " \o \o
2 ^0
2 , gas _ pair stomata
JC00 = ^gas . ..liquid CO, " RCO, RCO,
; _Scl& . XJ-4UJ.U W_ W0 uv/9
2 R- + RC02 222
assuming R^S = 1.56 R?a^ (see Nobel, 1976)
2 2
.. .. AC00 - 1.56 "^as
liquid 2
where J n and J are fluxes for water vapor and CCL, and AH00 is the
njU C.U~ 4 2
difference in water vapor concentrations between the leaf and air (assuming
the leaf to be saturated at leaf temperature). Rr is the total leaf
2
resistance to water vapor and can be partitioned into R^ , or boundary
2
i _ j -.stomata . -
layer resistance and R^ or resistance to water vapor movement out of
the leaf by stomata. R^ o was calculated using a filter paper leaf replica
2
in the cuvette. AGO- is the difference between the CO concentration in
ambient air and the site of carboxylation. Since this latter concentration
has been assumed to be equal to 0, Rpn contains all the resistances
other than boundary layer and stomatal resistances.
V-7
-------
The first series of measurements were begun after the soybeans received
a six hour, radiation flux of UV-B for 14 days (84 hrs). Gas exchange re-
sponses were monitored on an attached unifoliate leaf after the plants had
been fully watered. This procedure was repeated on the soybeans after 49 days
of a six hour radiation flux (294 hrs) of UV-B. Gas exchange measurements
were monitored on the center leaflet of the third fully expanded trifoliate
leaf.
Immediately following this second series of measurements, these same
leaves were exposed to a compressed gas mixture containing 2% oxygen, 350 pl/1
C09, and the balance nitrogen. Before entering the cuvette, this air stream
was humidified to achieve a vapor pressure deficit of 10 mb at a leaf
temperature of 30ฐC. Light response measurements of CO and HO vapor were
ฃป ฃ
performed as described earlier.
- In addition to these gas exchange data, measurements were made on plant
heights at weekly intervals. At the end of the experiment, plants were
harvested and separated into roots, stems and leaves for soybeans, and roots,
shoots, and inflorescences for wheat. Total leaf areas were measured with
a Lambda LI-3000 leaf area meter. Plant parts were dried in a ventilated
oven at 60ฐC to constant weight. UV-B damage was.visually assessed for
leaf chlorosis and interveinal wrinkling on a scale ranging between 0 and
9 (Table 2). The leaves used in the gas exchange experiments were removed
and analysed for total chlorophyll, chlorophyll a and b, and total protein.
Chlorophyll was determined by the method of Arnon (1949) and total proteins
by Lowry (1951).
Computations were facilitied by the use of the Northeast Regional Data
Center Amdahl 470 V/6 II Computer located at the University of Florida.
Statistical analysis employed use of stored programs in the Statistical
Analysis Systems (SAS 76.5).
V-8
-------
Table 2. Criteria used to rate the degree of UV-B associated leaf chlorosis
and interveinal wrinkling.
Index Value
Leaf Chlorosis
Interveinal Wrinkling
no damage, green leaves no damage, healthy leaves
yellow leaves present
very slight puckering between
leaves
yellow leaves with some
spots of intense yellow
definite puckering
yellow leaves with brown
patches
pronounced wrinkling
leaf margins dried and pronounced wrinkling and leaf curl
curled over, much of leaf evident
dried
V-9
-------
Results .
Gas Exchange
Net carbon exchange (NCE) was light saturated at an irradiance of
-2-1
1300 yE m sec in all three experiments (Figures 1, 9, and 16). Therefore,
an analysis of variance (ANOVA) was performed at this irradiance to test the
effects of UV-B dose and PAR level during growth on net carbon exchange,
transpiration, and the associated diffusive resistances. .A separate analysis
was done for dark respiration. A summary of these analyses are presented on
Table 3.
At the end of a two-week exposure, both UV-B and PAR flux levels were
associated with significant (P < 0.05) interactions in nearly all the vari-
ables examined. This was indicative of the complex nature of the combined
effects. UV-B-associated reductions and enhancements after two weeks of.
UV-B treatment were expressed as a percentage of the mylar control responses
in Table 4. NCE on a leaf weight basis was significantly (P < 0.05) reduced
in plants exposed to 2 UV-B and reduced PAR levels incident during growth.
seu
However, NCE is not significantly (P > 0.05) affected by UV-B when plants
were grown in full sunlight (compare Figure la with Figures Ib and c).
Similar results were obtained for NCE on a leaf area basis (Figure 2). At
the lowest PAR growth regime, NCE was equally reduced in plants exposed to
any UV-B treatment.
Moderate fluxes of UV-B radiation resulted in enhancements of NCE when
plants were grown under high PAR levels (Figures la and b and 2a and b).
These enhancements were most pronounced under non-saturated irradiances
-2 -1
(PAR less than 1300 yE m sec ).
V-10
-------
Table 3. Stransry of 2 way ANOVA on the effects of UV-B nnd PAR on soybenn NCE, transpiration, dark respiration, and the associated diffusive
resistances.I
2 veelcs UV-B exposure
6 uecks UV-B exposure
uv-u
df
NCE (BS C02-dn~2-hr-1) 3
NCE (mg COj-g^hr"1) 3
*"* !
Transpiration (g ป20 dn -hr ) 3
Transpiration (g 11,0 g~ -hr" ) 3
nsto:nata . -1. -
RCQ (sec -cm ) 3
R^uid (sec-cn-1) 3
<;
1 R e (sec* cm" ) 3
M CO,
R^toeata (sec. cm" ) 3
Dark respiration (og CO do'Tir" ) 3
Dark respiration (ng CO, g" hr ) 3
F
6.42***2
6.72***
7.62***
11.77***
5.16**
12.53***
12.90***
5.16**
1.57ns
2.13ns
PAR
df
3
3
3
3
3
3
3
3
3
3
F
8.72***
8.91...
13.41***
70.50***
8.46**ป
7.17***
5.85***
8.46***
20.29***
1.10ns
UV-BxPAR
df
8
8
8
8
8
8
8
a
a
8
F
1.74ns
3.20**
3.10**
4.02***
2.34*
7.15***
6.66***
2.34*
1.93ns
0.99ns
L'V-B
df
3
3
3
3
3
3
3
3
3
3
F
6.47***
12.60***
3.50*
15.11***
3.05*
2.88*
3.23*
3.05*
0.56ns
0.60ns
df
3
3
3
3
3
3
3
3
3
3
PAR
F
20.30***
2.38ns
2.66ns
18.94***
1.89ns
7.22***
6.93***
1.89ns
3.00*
1.25ns
UV-BxPAR
df
R
8
8
8
8
8
8
8
8.
8
P
0.81ns
1.03ns
1.96ns
4.49***
1.59ns
0.48ns
0.48ns
1.59ns
0.98ns
1.19ns
1 _2 !
"Irradlancc at the leaf surface uas 1300 uEn sec PAR; ariilcnt CO. and 0. concentrations
2* - significant at P<0.05
** - significant at P< 0.01
V* significant at P< 0.001
ns not significant
-------
Table * . Mean effects of 4 UV-B Irradiances and 4 shade levels on soybean NCE, transpiration, and the associated diffusive resistances after
two weeks exposure.1 Data in parenthesis are expressed as percent mylar control.
NCE (mg COjg"1!!
NCE (ing COjdnT^r"1)
Transpiration (g HjQ g" hi
Transpiration (g H.O da hr )
f : ""=
S3
ซonata (8ec.cn-l)
-stonata
Yo
Water use efficiency
(g H20 lost/g C02 fixed)
Shade2
0
56.57
a*
15.87
a
13.67
ab
3.81
a
ป
14.75
a
1.17
b
13.06
a
0.75
b
!46.60
a
Z
(5
72.91
a
(128.9)
17.23
a
(108.6)
16.97
0
(124.1)
4.22
a
(110.8)
15.31
a
(103.8)
0.98
b
(83.8)
13.81
a
(105.7)
0.63
b
(8'4.0)
293.4
a
(119.0)
0
1
56.94
a
(100.7)
15.68
n
(98.8)
12.36
ab
(9(1.4)
3.36
ab
(88.2)
14.74
a
(99.9)
1.69
ab
(144.4)
12.53
a
(95.9)
1.08
ab
(144.0)
208.77
a
(84.7)
2
62.68
a
(110.8)
14.96
a
(94.3)
9.72
b
(71.1)
2.32
b
(60.9)
15.19
a
(103.0)
2.42
a
(206.8)
12.24
a
(93.7)
1.55
a
(206.7)
155.0
a
(62.9)
0
74.18
ab
12.14
ab
18.54
b
3.02
b
19.50
ab
1.68
b
17.30
a
1.08
b
253.20
a
Z
ij
90.93
a
(122.6)
15.60
a
(128.5)
24.97
a
(134.7)
4.28
a
(141.7)
14.61
b
(74.9)
0.97
b
(57.7)
13.12
a
(75.8)
0.62
b
(57.4)
273.6
B
(108.1)
33
1
70.07
ab
(94.5)
14.62
a
(120.4)
15.25
be
(82.3)
3.13
b
(103.6)
16.55
b
(84.9)
1.71
b
(101.8)
14.31
a
(82.7)
1.10
b
(101.9)
224.9
a
(88.8)
2
55.82
b
(75.2)
9.86
b
(81.2)
11.87
c .
(64.0)
2.09
c
(69.2)
23.48
a
(120.4)
2.78
a
(165.5)
20.17
a
(116.6)
1.78
a
(164.8)
213.0
a
(84.1)
0
100.12
a
13.07
a
32.16
a
4.20
b
18.37
a
0.91
ab
16.94
' a
0.58
ab
334.4
b
Z
!j
92.49
a
(92.4)
13.90
a
(106.4)
34.92
.1
(108.6)
5.25
a
(125.0)
16.74
n
(91.1)
0.62
b
(68.1)
15.59
a
(92.0)
0.40
b
(69.0)
384.3
b
(114.9)
55
1
90.90
a
(90.8)
15.78
a
(120.7)
24.34
b
(75.7)
4.28
b
(ini.9)
15.51
a
(84.4)
0.93
ab
(102.2)
14.05
a
(82.9)
0.59
ab
(101.7)
286.8
b
(85.8)
2
27.71
b
(27.7)
5.54
b
(42.4)
19.57
b
(60.9)
3.88
b
(92.4)
48.65
b
(264.8)
1.08
a
(118.7)
47.05
b
(277.7)
0.69
a
(119.0)
302.7
a
(240.0)
lj
72.76
ab
11.33
a
24.43
ab
3.82
a
20.14
a
1.14
ab
18.47
b
0.73
a
338.4
b
Z - 88
1
80.80
a
11.00
a
22.49
b
3.06
b
21.06
a
1.71
a
18.83
b
1.09
a
278.7
c
3
2
61.39
b
9.27
a
29.27
a
4.42
a
24.60
a
0.85
b
23.22
a
0.55
a
477.9
a
2Plants accumulated UV-B for 14-17 days. Means for leaf irradlance - 1300 uEn" nee"1 PARj aobjent OOj 320 pLL"
.Expressed as percent Incident radiation shaded. Mean daily unshaded oaxlnun 1600 uEra sec PAR
.Mylar control plants could not be neasured
Values in rovs under each level of shade with the sane letter are not statistically different at the 95Z level
-------
Figure 1. Effects of four UV-B irradiances and four PAR levels on net car-
bon exchange (NCE) in soybeans after 14 days exposure. Plotted
are the mean NCE rates on a leaf dry weight basis (MPSW) against
-2 -1
irradiance supplied to the leaf surface (RAD) in uE m sec PAR.
MPSW is expressed in mg OCU-g -hr . Each mean is based on
4-5 observations. Numbers in each curve represent UV-B ir-
radiances. Omylar control, 5=% UV-B , 1=1 .UV-B ,
S 6UL S t-li
2=2 UV-B . Vertical bars connect curves that are not
seu
significantly different at the 95% level. In Figure 1A plants
were grown under unshaded ambient irradiances in a temperature
controlled greenhouse. Average maximum daily unshaded ir-
-2 -1
radiance=1600 uE in sec PAR. Figures IB, C, and D were grown
under 33, 55, and 88% shade, respectively.
V-13
-------
MPSW
96
16
-J 6
MPSW
60
64
32
16
-It
000
300
400
eoo
PAD
1 200
A
MPSW
06
c
1600
64
48
I 6
-1 6
MPSW
ao
64
48
-16
400
_ flOO .
PAD
1 TOO
B
\ 6OO
D
1600
-------
Figure 2. Effects of four UV-B irradiances and four EAR levels on net car-
bon exchange (NCE) in soybeans after 14 days exposure. Plotted
are the mean NCE rates on a leaf area basis (MPSA) against
-2 -1
irradiance supplied to the leaf surface (RAD) in uE m sec PAR.
-2 -1
MPSA is expressed in mg CCu-dm -hr . Each mean is based on
4-5 observations. Numbers in each curve represent UV-B ir-
radiances. Omylar control, 5=% UV-BOQ1 , 1=1 UV-BOQ1 ,
S c U. SGXJ.
2=2 UV-B . Vertical bars connect curves that are not
S G VI
significantly different at the 95% level. In Figure 1A plants
were grown under unshaded ambient irradiances in a temperature
controlled greenhouse. Average maximum daily unshaded ir-
-2 -1
radiance=1600 uE m sec PAR. Figures IB, C, and D were
grown under 33, 55, and 8870 shade, respectively.
V-15
-------
MPSA
19
IS
-3
MPSA
ia
is
-3 :
400 flOO
OAD
400
eoi>
RAD
4-
1200
A
1200 1*00
c
MPSA
1.8
15
12
MPSA
18
12
-3
400
eoo
PAD
. aoo
RAD
1200
12CO
B
1600
D
16OU
-------
leaf
The total leaf resistance to the diffusion of CO , R , was greatest
2- v>u_
in plants exposed to 2 UV-B and intermediate PAR flux levels (Figure 3) .
S CU
leaf
Between PAR irradiances of 0 and 33% shade, UV-B flux had no effect on R
CU2
leaf
However, R from soybeans grown in irradiances of 33% shade and below were
2
increasingly affected by 2 UV-B (Table 4). R accounted for 80% to
SGU L*\-/rt
-i
90% of the total leaf resistance to CO (15 to 25 cm ). Therefore, the re-
.. .liquid ..., , . r,lsaf ,_,. , ,. -liquid . ....
sponses of R,,^ were reflected in R (Figure 4). R,,,-. was signifi-
cu~ co~ co_
cantly (P < 0.05) greater in plants grown under 2 UV-B and moderate to low
seu
PAR levels (Table 4).
nce to CO diffusion, R
/~
Stomatal resistance to CO diffusion, R accounted for approxi-
mately 10 to 20% of Rpn (Figure 5). ฃฐ*-umaL-cl was greatest in those soybeans
CU2 GO 2
grown under 2 UV-Bgeu and between 0 and 33% shade (Table 4). R^omata Qf
2
soybeans exposed to 1/2 UV-B was always less than that of controls. UV-B
J c seu J
S t OIT13.13
fluxes greater than this resulted in a significant increase in R
Therefore, 2 UV-B resulted in both higher RjoqUld and R^ฐmata, but these
seu 2 2
resistances were greatest under different PAR regimes.. At the high PAR
irradiances, increased UV-B flux affected NCE primarily by increase of
R . Therefore, despite relatively lower Rpr. , NCE remained essen-
2 2 ......
tially unaffected. However, when grown in lox\rer irradiances, Rpn became
increasingly more important in restricting NCE. The UV-B associated
enhancements in NCE seemed primarily to be .due to decreases in the stomatal
resistances of soybeans exposed to 1/2 UV-B (Table 4).
S GU
After a two week treatment, transpiration on both an area and a weight
basis was significantly (P < 0.01) affected by the interaction between UV-B
flux and PAR level (Table 3). In general, transpiration on an area basis
was greater in soybeans grown under higher PAR flux levels (Figure 7).
Transpiration in soybeans grown under high PAR levels varied inversely with
V-17
-------
Figure 3. Effects of four UV-B irradiances and four PAR levels on total
leaf
leaf resistance to CCL (R^ ) in soybeans after 14 days ex-
leaf -1
posure. Plotted are the mean R~ in sec-cm (MRCCELL)
against irradiance supplied to the leaf surface (RAD) in
-2 -1
. uE in sec PAR. Each mean is based on 4-5 observations.
Numbers in each curve represent UV-B irradiances. Omylar
control, 5=% .UV-Bgeu, 1=1 UV-Bseu, 2=2 UV-Bgeu.. Vertical
bars connect curves that are not significantly different at
the 9570 level. In Figure 1A plants were grown under unshaded
ambient irradiances in a temperature controlled greenhouse.
-2 -1
Average maximum daily unshaded irradiance=1600 uE m sec PAR.
Figures IB, C, and D were grown under 33, 55, and 88% shade,
respectively.
V-18
-------
M
VO
eo
70
60
1 0
MPCCPLL
eo
70
50
40
10
0
30O
600
KfD
300
600
"?00
A
OO
(rAC
TOO
600
RAD
900
B
1 200
D
1200
-------
Figure 4. Effects of four UV-B irradiances and four PAR levels on liquid
phase resistances to OCL (" ^ ^ soybeans after 14 days
exposure. Plotted are the mean Rr~ in sec -on" (MRCLIQ)
against irradiance supplied to the leaf surface (RAD) in
-2-1
uE m sec . PAR. Each mean is based on 4-5 observations.
Numbers in each curve represent UV-B irradiances. Omylar
control, 5=% UV-Bseu, 1=1 UV-Bseu, 2=2 UV-Bgeu. . Vertical
bars connect curves that are not significantly different at
the 9570 level. In Figure 1A plants were grown under unshaded
ambient irradiances in a temperature controlled greenhouse.
-2 -1
Average maximum daily unshaded irradiance=1600 uE m sec PAR.
Figures IB, C, and D were grown under 33, 55, and 88% shade,
respectively.
v-20
-------
f
MRCLIC
84
72
60
24
12
MRCLIO
flA
60
36
24
12
u
PAD
300
oOO
PAL)
SOU
A
OOO 1200
c
1200
MPCLIQ
84
60
48
24
0
MPCL 10
84
?6
1 2
?00
300
6uU
WAO
9OO
B
3 200
D
1200
-------
Figure 5. Effects of four UV-B irradiances and four PAR levels on stomatal
resistances to C09 (R ) in soybeans after 14 days exposure.
/- UปJQ
Plotted are the mean R^01021113 in sec -cm"1 (MRCSTOM) against
2 _2 -1
irradiance supplied to the leaf surface (RAD) in uE m sec PAR.
Each mean is based on 4-5 observations. Numbers in each curve
represent UV-B irradiances. Omylar control, 5=% UV-B
1=1 UV-B , 2=2 UV-B . Vertical bars connect curves
o t: U.
that are not significantly different at the 9570 level. In
Figure 1A. plants x\7ere grown under unshaded ambient irradiances
in a tenperature controlled greenhouse. Average maximum daily
-2 -1
unshaded irradiance=1600 uE m sec PAR. Figures IB, C, and
D were grown under 33, 55, and 88% shade, respectively.
v-22
-------
f
K3
U>
MRCSTOM
t 1 .2
R .0
6.4
4.8
3.2
1 .6
0.0
MPCSTPM
! 1 .2
A.O
6.4
4 .6
3.2
1.6
0.0
400
sco
HAC
400
SCO
RAC
1200
:?oo
A
ftOO
C
5 600
MRC?TCM
1 1 .?
0.6
a .0
6.4
4.0
I .6
0 .0
f 1.2
9. e
9.0
6,4
1 .6
0 .0
400
0 400
c . ' '. ' .
12 00
WOO
FJAC
1LOO
B
1 6OO
D
1 600
-------
Figure 6. Effects of four UV-B irradiances and four PAR levels on leaf
transpiration in soybeans after 14 days exposure. Plotted are
the mean transpiration rates on leaf dry weight basis (MTSW)
against irradiance supplied to the leaf surface (RAD) in
-2 -1 -1 -1
uE m sec PAR. Transpiration was expressed in g H^Org -hr .
Each mean is based on 4-5 observations. Numbers in each curve
represent UV-B irradiances. Omylar control, 5=% UV-B
1=1 UV-B , 2=2 UV-B . . Vertical bars connect curves
seu' seu
that are not significantly different at the 95% level. In
Figure 1A plants were grown under unshaded ambient irradiances
in a temperature controlled greenhouse. Average maximum daily
-2 -1
unshaded irradiance=1600 uE m sec PAR. Figures IB, C, and
D were grown under 33, 55, and 88% shade, respectively.
V-24
-------
ro
MTSW
35
30
20
15
t 0
4 00
MTSW
35
30
15
' 1 0
400
" AU
boo
OAD
1 ,700
1 2CO
A
1600
c
leoo
MTSW
35
30
20
10
MTSW
35
30
1 5
JO
B
4Oo e-oj i.?oo itoo
PAD
D
-------
f 1
Figure 7 . Effects of four UV-B irradiances and f our PAR levels on leaf
transpiration in soybeans after 14 days exposure. Plotted are
the mean transpiration rates on a leaf area basis (MTSA)
against irradiance supplied to the leaf surface (RAD) in
-2-1 -2 -1
uE m sec PAR. MTSA is expressed m g ILO-dm -hr . Each
mean .is based on 4-5 observations. Numbers in each curve
represent UV-B irradiances. Omylar control, 5=% UV-B
1=1 uv"Bseuป 2=2 uv-Bseu- Vertical bars connect curves
that are not significantly different at the 95% level. In
Figure 1A plants were grown under unshaded ambient irradiances
in a temperature controlled greenhouse. Average maximum daily
-2-1
unshaded irradiance=1600 uE m sec PAR. Figures IB, C, and
D were grown under 33, 55, and 88% shade, respectively.
V-26
-------
S3
5. 6
4. P
4 .0
3.2
2.4
i. e
o.o
VTSA
4.8
4.0
1 .6
O.B
0.0
000
HOO
ra AD
eoo
PAt)
inco
A
c
MTSA
5.6
4 .a
4. 0
2. 4
1 .6
o. e
o. o
MTSA
5.6
4. e
4. 0
2.4
.6
0. 0
6 00
'tOO
bOO
-4-
.eoo
RAO
?00
B
1600
1-SOO
-------
UV-B flux and was intermediate for the mylar controls and lowest for plants
exposed to 2 UV-B . However, this relationship changed in soybeans grown
S6X1
under the lowest PAR flux level (Figures 6d and 7d) . In this reduced PAR
regime, transpiration was lower in soybean exposed to 1 than those exposed
to 2 UV-B
seu
Stomatal resistances to the diffusion of water vapor, R^ , were
greatest in plants exposed to 2 UV-B in high to moderate PAR conditions
S GU
(Table 4). The effects of UV-B and PAR on stomatal resistances resulted in
a greater water use efficiency in soybeans grown under high PAR levels and
2 UV-B . However, when PAR levels were reduced, water use efficiency for
seu J
soybeans exposed to 2 UV-B was reduced by diminishing NCE rates (Table 4) .
ScU
Dark respiration was unaffected by UV-B flux on both a leaf weight and
on a leaf area basis (Table 3). However, dark respiration on an area basis
was strongly affected by PAR. Specific leaf thickness increased with level
of PAR during growth. Therefore, dark respiration is more a function of cell
volume or weight rather than leaf surface area.
By the end of six weeks of exposure, the UV-B x PAR interaction changed,
as indicated by the decrease in the number of significant UV-B and PAR
interaction terms (Table 3) . NCE on a leaf weight basis was reduced by UV-B
enhancement in all PAR regimes, particularly becoming pronounced at inter-
mediate irradiances (Figure 8) . The reduction in NCE was directly related to
UV-B flux. Even UV-B fluxes approximating those commonly experienced in the
field resulted in decreased NCE rates (Table 5). Similar results were
obtained for NCE on a leaf area basis (Figure 9) . NCE on a leaf area basis
was additionally reduced as a function of PAR available to the plant during
growth.
V-28
-------
Figure 8. Effects of four UV-B irradiances and four PAR levels on net
carbon exchange (NCE) in soybeans after 49 days exposure.
Plotted are the mean NCE rates on a leaf dry weight basis (MPSW)
against irradiance supplied to the leaf surface (RAD) in
-2 -1
uE m sec PAR. Each mean is based on 4-5 observations. Num-
bers in each curve represent UV-B irradiances. 0=mylar control,
5=^ UV-Sseu'- 1=1 UV"Bseu? 2=2 UV~Bseu' Vertical bars
connect curves that are not significantly different at the
9570 level. In Figure 1A plants were grown under unshaded
ambient irradiances in a temperature controlled greenhouse.
-2 -1
Average maximum daily unshaded irradiance=1600 uE m sec PAR.
Figures IB, C, and D were grown under 33, 55, and 88% shade,
respectively.
V-29
-------
f
u>
o
MPSW
7?
60
36
12
-12
60
4B
36
12
-12
400
400
eoo
PAD
MOJ
PAD
12CO
A
-1600
c
1200. . . 1600
MPSW
72
60
48
36
1 2
-12
MPSX
72
60
1 2
-1 2
100
sou
D AD
400
eoo
PAD
1200
B
lf-00
D
1200 U..OU
-------
Table 5 . Mean effects of 4 UV-B Irradlancea and 4 shade levels on soybean NCE, transpiration, and the associated diffusive resistances after 6 weeks
of treatment.1 Data in parenthesis are expressed aa percent nylar -control.
Shade2
UV-B
seu
NCE (mg CO e^hr"1)
2
NCE (mg COjdra" hr" )
Transpiration (g H20 g'^hr"1)
Transpiration (g H20 dn^hr"1)
Rl?aฃ (sec en"1)
C02
Rstomata (sec co-l)
Cฐ2
Rli1 1
54.2 56.20
a a
(100.4X104.1)
12.96 15.17
a a
(90.7X106.2)
19.55 16.23
a ab
(131.5X109.1)
4.68 4.38
a a
(118.8X111.2)
17.76 15.01
a a
(107.1) (90.5)
2.13 2.22
a a
(75.3) (78.4)
15.11 12.27
ab b
(114.2) (92.7)
1.37 1.43
a a
(75.7) (79.0)
363.7 291.3
a be
(133.4)(106.8)
1.48 1.88
a a
(75.1) (95.4)
0.54 0.68
b ab
(72.0) (90.7)
2.03 2.56
a a
(74.6) (94.1)
3.59 7.45
a a
(56.9X118.3)
2
44.83
a
(83.0)
11.64
a
(81.5)
15.34
ab
(103.2)
3.98
a
(101.0)
19.65
a
(118.7)
2.66
a
(94.0)
16.47
a
(109.0)
1.71
a
(94.5)
343.8
ab
(126.1)
1.88
a
(95.4)
0.68
ab
(90.7)
2.48
a
(91.2)
8.86
a
(140.6)
Z
0 S
62.20 60.76
a a
(97.7)
9.77 11.64
ab a
(119.1)
27.92 17.80
a b
(63.8)
4.39 3.42
a ab
(77.9)
23.43 19.81
. ab b
(84.5)
2.26 3.28
b ab
(145.1)
20.65 16.01
ab b
(77.5)
1.45 2.10
b ab
(144.8)
450.7 299.9
a b
(66.5)
1.35 1.45
b b
(107.4)
0.53 0.59
b ab
(111.3)
1.88 2.04
b a
(108.5)
8.34 5.85
a a
(70.1)
' 33
1 2
44.86 42.61
b b
(72.1) (68.5)
10.97 8.42
3b b
(112.3) (86.2)
15.68 14.83
b b
(56.2) (53.1)
3.81 2.94
ab b
(86.8) (67.0)
21.44 27.93
ab a
(91.5) (119.2)
2.62 4.18
ab a
(115.9) (185.0)
18.30 23.23
ab a
(88.6) (112.5)
1.68 2.68
ab a
(115.9) (184.8)
359.8 348.0
ab ab
'(79.8) (77.2)
1.65 1.80
nb a
(122.2) (133.3)
0.62 0.73
rib a
(117.0) (137.7)
2.26 2.53
ab a
(120.2) (134.6)
3.58 9.45
a a
(42.9) (113.3)
0
70.94
a
10.05
ab
31.63
a
4.50
a
23.40
ab
2.11
b
20.76
ab
1.35
b
462.8
a
1.27
ab
0.50
a
1.77
a
2.87
b
Z - 55
>3 1
70.13 56.13
a a
(98.9) (79.1)
10.04 12.08
ab a
(99.9) (120.2)
24.18 18.52
b c
(76.4) (58.6)
3.45 3.94
ab b
(76.7) (87.6)
23.00 196.4
. ab b
(98.3) (83.9)
3.17 2.52
a ab
(150.2) (119.4)
19.31 16.59
ab b
(93.0) (79.9)
2.03 1.62
a ab
(150.4) (120.0)
341.9 336.3
ab b
(73.9) (72.7)
1.13 1.58
b a
(89.0) (124.4)
0.46 0.59
a a
(92.0) (118.0)
1.59 2.17
a a
(89.8) (122.6)
3.85 8.51
ab a
(134.1) (296.5)
2
39.50
b
(55.7)
7.88
b
(78.4)
17.36
(54.9)
3.45
b
(76.7)
29.79
a
(124.7)
2.94
a
(139.3)
25.72
a
(123.9)
1.89
a
(140.0)
445.5
ab
(96.3)
1.25
ab
(98.4)
0.50
a
(100)
. 1.75
a
(98.9)
3.82
ab
(133.1)
Z -
lj
56.97
a
8.27
a
32.57
a
4.75
a
28.10
a
2.03
a
25.55
a
1.30
a
582.1
a
0.95 1.27
b a
0.39 0.56
b a
1.34 1.83
b a
6.47 3.50
a a
883
1
45.71
a
7.30
a
23.04
b
3.68
a
31.54
a
2.71
a
28.30
a
1.74
a
517.5
a
1.32
a
0.52
a
1.84
a
5.96
a
2
35.01
a
. 6.44
a
19.64
b
3.64
a
48.81
a
3.12
a
45.16
a
2.00
a
707.4
a
1.21
ab
0.48
ab
1.69
ab
6.43
a
'Plants accumulated UV-B for 40-42 days. Means for leaf irradlance 1300 uEm^sec"1 PAR. ambient O>2 - 320 ULL
^Expressed aa percent incident radiation shaded. Mean dally unshaded maximum 1600 pEa~2Bec-l PAR
'.Mylar control planta could not be measured
^Values in rows under each level of ahade with the sane letter are not statistically different at the 95Z level
-------
Figure 9. Effects of four UV-B irradiances and four PAR levels on net
carbon exchange (NCE) in soybeans after 49 days exposure.
Plotted are the mean NCE rates on a leaf area basis (MPSA)
against irradiance supplied to the leaf surface (RAD) in
-2 -1
uE m sec PAR. Each mean is based on 4-5 observations. Num-
bers in each curve represent UV-B irradiances. Omylar control,
5=^% UV-B , 1=1 -UV-B 2=2 UV-B . Vertical bars
2 seu' seu seu
connect curves that are not significantly different at the 9570
level. In Figure 1A plants were grown under unshaded ambient
irradiances in a temperature controlled greenhouse. Average
-2 -1
maximum daily unshaded irradiance=1600 uE m sec PAR. Figures
IB, C, and D were grown under 33, 55, and 8870 shade, respectively.
V-32
-------
U>
U)
MPSA
! 5
10
-5
MPSA
15
-5
SuO
PAD
A
AGO 800 1200 1600
PAO
c
12CO . . .1600
IS
1 0
-5
MPSA
'. 5
-5
AGO
600
PAD
B
400 800 t"00 160O
PAD
D
1200 J600
-------
Rrn was significantly affected both by UV-B flux (P < 0.05) and PAR
L02
leaf
irradiance (P < 0.001). R x^as greatest in soybeans exposed to 2 UV-B
\j\J ซ S G U
in all PAR treatments and varied inversely with PAR level (Figure 10).
R contained most of the total leaf resistance to C00 and increased
, CO/) Z
directly with UV-B flux and inversely with PAR (Figure 11). In general,
Rr was unaffected by PAR level but was significantly (P < 0.05) in-
CUrt
. . . __T _ _stomata , .
creased by increasing UV-B. R was greatest in tnose plants exposed
L0~
to 2 UV-B . This is particularly evident in soybeans grown in reduced PAR
Sell
levels (Figure 12).
After six weeks exposure, transpiration on a leaf area basis was signifi-
cantly (P < 0.05) affected by UV-B flux but not by PAR (Table 3). Soybeans
grown in moderate to low PAR levels and exposed to UV-B had reduced transpira-
tion rates compared with controls on both a leaf weight and area basis (Figures
13 and 14). Under the highest PAR regime, UV-B had no significant (P > 0.05)
effect on transpiration. The reduction in transpiration with increasing
o t* f\
UV-B flux was reflected in increasing stomatal resistances, R
n2o
(Figure 15).
When grown under unshaded conditions the greater NCE rates of control
plants resulted in a significantly (P < 0.05) greater water use efficiency.
Water use efficiency was reduced in control soybeans when grown under lower
PAR levels due to both increased R and lower NCE rates. Dark respira-
LซL/ n
tion was unaffected by UV-B exposure after 6 weeks.
Leaf protein and chlorophyll contents are shown on Table 5. After
seven weeks of treatment, leaf total protein on a x^eight basis x^as unaffected
by UV-B or PAR. Chlorophyll b was associated x^ith a significant (P < 0.05)
UV-B x PAR interaction, x^hich was also reflected in total chlorophyll. * In
general, total chlorophyll decreased as PAR was reduced. Under high PAR
V-3A
-------
Figure 10. Effects of four UV-B irradiances and four PAR levels on total
leaf
leaf resistance to 002 ^00 ^ "^ soyt)eans after 4-9 days ex-~
leaf -1
posure. Plotted are the mean Ri.- in sec-on (MRCCELL)
UJ2
against irradiance supplied to the leaf surface (RAD) in
-2 -1
uE m sec PAR. Each msan is based on 4-5 observations.
Numbers in each curve represent UV-B irradiances. Omylar
control, 5=% UV-B , 1=1 UV-B , 2=2 UV-Bo . Vertical
seu' seu' seu
bars connect curves that are not significantly different at
the 95% level. In Figure 1A plants were grown under unshaded
ambient irradiances in a temperature controlled greenhouse.
-2 -1
Average maximum daily unshaded irradiance=1600 uE m sec PAR.
Figures IB, C, and D were grown under 33, 55, and 8870 shade,
respectively.
V-35
-------
f
u>
ON
MPCCPLL
64
56
48
1 6
MRCCELL
64
56
40
32
24
16
',00
t-oo
RAD
-------
Figure 11. Effects of four UV-B irradiances and four PAR levels on liquid
phase resistances to CCL (^~ ^ ^ soy^eans after 49 days
exposure. Plotted are the msan Rrffi*L in sec -cm" (MRCLIQ)
against irradiance supplied to the leaf surface (RAD) in
-2-1
uE m sec PAR. Each mean is based on 4-5 observations.
Numbers in each curve represent UV-B irradiances. 0=mylar
control, 5=% .UV-B 1=1 UV-UsฃU> 2=2 UV-Bseu. Vertical-
bars connect curves that are not significantly different at
the 957o level. In Figure 1A plants were grown under unshaded
ambient irradiances in a temperature controlled greenhouse.
-2 -1
Average maxunum daily unshaded irradiance=1600 uE m sec PAR.
Figures IB, C, and D were grown under 33, 55, and 8870 shade,
respectively.
v-37
-------
Figure 12. Effects of four UV-B irradiances and four PAR levels on stomatal
resistances to GOo f^ ) ^ soybeans after 49 days exposure.
Plotted are the mean R in sec- on"1 (MRCSTOM) against
2 _2 ^i
irradiance supplied to the leaf surface (RAD) in uE m sec PAR.
Each mean is based on 4-5 observations . Numbers in each curve
represent UV-B irradiances. Omylar control, 5=% UV-B ,
S G \JL
1=1 UV-B , 2=2 UV-B . . Vertical bars connect curves
seu' seu
that are not significantly different at the 957o level. In
. Figure 1A plants were grown under unshaded ambient irradiances
in a temperature controlled greenhouse. Average maximum
-2 -1
daily unshaded irradiance=1600 uE m sec PAR. Figures IB, C,
and D were grown under 33, 55, and 88% shade, respectively.
V-39
-------
-P-
o
MRCSTQM
20
15
10
MRCSTOM
30
10
AOO
1 A
20
ts
10
5
400 HOG 1200 1600
KAO
c
N'RCSTPM
?0
10
1200 16OO
RAO
A 00 t'CO
RAC
B
AOO HOO t ?.00 1 600
RAC
D
i?oo \ e-oo
-------
Figure 13. Effects of four UV-B irradiances and four PAR levels on leaf
transpiration in soybeans after 49 days exposure. Plotted are
the mean transpiration rates on a leaf dry weight basis (MTSW)
against irradiance supplied to the leaf surface (RAD) in
uE m sec PAR. MTSW is expressed in g H20-g~1-hr" .. Each
mean is based on 4-5 observations. Numbers in each curve
.represent UV-B irradiances. Omylar control, 5=% UV-B ,
S G u.
1=1 ..UV-B , 2=2 UV-B . . Vertical bars connect curves
seu' seu
that are not significantly different at the 95% level. In
Figure 1A plants were grown under unshaded ambient irradiances
in a temperature controlled greenhouse. Average maximum daily
-2 -1
unshaded irradiance=1600 uE m sec PAR. Figures IB, C, and
D were grown under 33, 55, and 88% shade, respectively.
V-41
-------
MTStK
*>
K)
20
16
12
MTSW
20
16
12
400
eoo
" AD
120C
400
BOO
PAD
A
MTSW
1600
c
1200 1600
20
J 6
12
MTSW
28
1.6
12
too
eoo
f AD
400
POO
DAD
i?oo
B
J.?OO 1600
D
1600
-------
Figure 14. Effects of four UV-B irradiances and four EAR levels on leaf
transpiration in soybeans after 49 days exposure. Plotted are
the mean transpiration rates on a leaf area basis (MTSA)
against irradiance supplied to the leaf surface (RAD) in
uE m sec PAR. MESA is expressed in g H20-dm~2-hr . Each
mean is based on 4-5 observations. Numbers in each curve
represent UV-B irradiances. CHrrylar control, 5=% UV-B
1=1 UV-B , 2=2 UV-B . Vertical bars connect curves
that are not significantly different at the 95% level. In
Figure 1A plants V7ere grown under unshaded ambient Irradiances
in a temperature controlled greenhouse. Average maximum daily
-2 -1
unshaded irradiance=1600 uE m sec PAR. Figures IB, C, and
D were grown under 33, 55, and 88% shade, respectively.
V-43
-------
MTSA
E.O
4. f=
4. 0
3.0
2.5
?. 0
t .5
MTSA
5.0
4.S
4.0
3.5
3.0
2.5
2. 0
1 .5
400
o AD
A
1200 1600
C
MTSA
5.0
4. 5
4.0
3 .5
3.0
2.5
2.0
1 .5
MTfA
5.0
.S
3.5 .
3.0
?. 0
1. 5
600
PAD
12OO
B
D
400
rtOO
PAD
t2CO. . . I'iOO.
bOJ
PAD
1200
U.OO
-------
Figure 15. Effects of four UV-B irradiances and four PAR levels on stomatal
of"fflT|ot~Q
resistances to water vapor (Rj Q ) in soybeans after 49 days
exposure. Plotted are the mean BJ|tQDat:a in sec-on"1 (MRHSTOM)
against irradiance supplied to the leaf surface (RAD) in
-2 -1
uE m sec PAR. Each mean is based on 4-5 observations. Num-
bers in each curve represent UV-B irradiances. 0=mylar control,
5=% UV-B 1=1 UV-B 2=2 UV-B Vertical bars
seu' seu' seu'
connect curves that are not significantly different at the
957o level. In Figure 1A plants were grown under unshaded
ambient irradiances in a temperature controlled greenhouse.
-2 -1
Average maximum daily unshaded irradiance=1600 uE m sec PAR.
Figures IB, c, and D were grown under 33, 55, and 887o shade,
respectively.
V-45
-------
MPHSTOW
12
MRHSTCM
1 2
ปIO.O
' RAO
A
'.2
400 POO 1?00 1()00
PAL:
C
MRHSTOM
1 2
400
1200 toOO
400
HOO .
B
'
-------
regimes, chlorophyll b was lower in soybean leaves exposed to UV-B than those
grown under mylar. However, under reduced PAR levels, this relationship
reversed. Chlorophyll a was significantly affected both by UV-B (P < 0.01)
and PAR (P < 0.001). UV-B had no effect on chlorophyll a content under high
PAR levels. However, when PAR was reduced, significant UV-B associated
effects were produced. In 33% shade, chlorophyll a content was greatest in
soybeans exposed to 2 UV-B and least when exposed to 1/2 UV-B or no
seu seu
UV-B treatment. Soybeans grown in 55% shade had the greatest chlorophyll a
content in leaves exposed to 1 UV-B and the least in those exposed to
seu
1/2 UV-B . At the lowest: PAR level, chlorophyll a was greatest in plants
S cU
exposed to 1/2 or 1 UV-B and least in mylar controls.
seu
A summary of the gas exchange measurements made in 2% 0_ are presented
in Table 6. Except for plants grox^n in 33% shade, NCE on both a leaf area
and leaf weight basis was greatest for soybeans exposed to 1/2 UV-B
S6U
Soybeans grown under 55 and 88% shade levels and exposed to 1/2 UV-B
resulted in significantly greater (P < 0.05) NCE rates than those of other
UV-B treatments or the mylar controls. In full sunlight, this increase in
NCE was not significant. In all three of these PAR regimes, there were no
significant differences between plants exposed to 0 (mylar), 1 or 2 UV-B
seu
All UV-B exposures resulted in decreased NCE rates when soybeans were
maintained in 33% shade. Increases in NCE were primarily due to decreased
liquid . stomata
R , but contributions also came from decreasing R
cu_ cu_
Transpiration rates followed patterns similar to those of NCE, again
reflecting the stomatal contribution through diffusive resistances.
V-47
-------
Tabel 6. Mean effects of 4 UV-B Irrodtanceo and 4 shade levels on NCE, transpiration, and the associated diffusive realatancea In soybeans measured In 2Z
oxygenk Data in parenthesis expressed as percent mylar control.
Shade2
UV-B
seu
; NCE (nig CO.-g ซhr )
'
-2 -1
NCE (mg CO ,'dn -hr )
! ฐ 2
1 1
Transpiration (g H.O.g >hr )
ฃ
Transpiration (g H,0.dm~ -hr~ )
i
1 A1 f 1 '
-leaf . l.
R_- (sec-cm )
C02
gStomata (sec.cn~lj
CO-
stomata . f -1.
2ฐ
Vater use efficiency
(g H20/g C02)
0
32.77
a
8.80
a
4.88
c
1.30
b
32.57
a
8.12
ab
23.92
a
5.21
ab
161.21
be
X
>1
45.46
a
(138.7)
10.85
a
(123.3)
10.27
a
(210.5)
2.46
a
(189.2)
24.87
a
(76.4)
3.76
b
C-6.3)
20.58
a
(86.0)
2.41
b
(46.3)
234.13
a
(145.2)
- 0
1
33.54
a
(102.3)
9.07
a
(103.1)
5.04
c
(103.3)
1.37
b
(105.4)
28.99
a
(89.0)
9.10
a
(112.1)
19.36
a
(80.9)
5.84
a
(112.1)
146.67
c
(91.0)
2
33.67
a
(102.7)
0.73
a
(99.2)
7.62
b
(156.4)
1.98
a
(152.3)
29.44
a
(90.4)
4.91
ab
(60.5)
24.00
a
(100.3)
3.15
ab
(60.5)
225.82
ab
(140.1)
0
82.80
a
13.01
ab
23.03
n
3.62
a
20.03
b
2.19
b
17.31
ab
1.40
b
282.72
a
; .
L
47.14
b
(56.9)
9.0ft
b
(69.9)
11.69
b
(50.8)
2.42
b
(61.9)
28.87
a
(144.1)
4.23
a
(193.2)
24.12
a
(168.6)
2./1
a
(192.2)
254.02
ab
(89.8)
33
1
59.64
b
(72.0)
14.77
a
(113.5)
12.46
b
(54.1)
3.06
a
(84.5)
18.00
b
(89.9)
2.82
b
(128.8)
14.65
b
(102.4)
1.81
b
(128.4)
214.03
ab
(75.7)
Z - 55
2
58.12
b
(72.0)
11.47
nb
(83.2)
11.10
b
(48.2)
2.19
b
(60.5)
22.61
ab
(112.9)
4.31
a
(196.8)
17.78
ab
(124.2)
2.76
a
(195.7)
193.55
ab
(68.4)
0 "i
64.58 97.44
b a
(150.9)
9.17 14.07
b a
053.4)
20.07 24.82
b a
(123.7)
2.86 3.57
b a
(124.8)
27.98 18.57
a b
(66.4)
3.17 2.23
b b
(70.3)
27.98 18.57
a b
(65.1)
2.04 1.43
b b
(70.1)
315.31 261.16
a a
(82.8)
1 2
47.14 46.64
b b
(73.0) (72.2)
9.55 9.29
b b
(103.9) (101.3)
7.80 15.29
a c
(38.9) (76.2)
1.58 3.04
c ab
(55.2) (106.3)
27.10 29.65
a a
(96.9) (106.0)
6.79 2.84
a b
(214.2) (89.6)
27.10 29.65
a a
(81.5) (108.2)
4.35 1.82
a b
(213.2) (89.2)
164.20 340.77
b a
(52.1) (108.1)
* - 88
0 >i 1 2
37.73 62.40 28.10 20.65
b a b b
(165.4) (74.5) (54.7)
7.99 9.05 4.50 3.75
a a b b
(113.3) (56.3) <46.9)
10.64 19.55 7.44 8.62
b a b b
(183.6) (70.0) (81. 0)
2.23 2.85 1.19 1.56
ab a c be
(127.8) (53.4) (70.0)
32.45 28.64 63.36 102.38
b b ab a
(88.3) (195.3) (315.6)
4.28 3.19 11.75 7.27
b b a ab
(74.5) (274.5) (169.5)
27.65 24.93 51.08 94.58
b b b -a
(90.2) (184.8) (342.1)
2.74 2.04 7.54 4.66
b b a ab
(74.5) (275.2) (170.1)
279.90 '315.65 254.82 593.85
b b b a
(112.8) (91.0) (212.1)
jPlants were exposed to UV-B for 49 days ' -2-1
Expressed as percent Incident irradiance shaded. Average daily aaxloun unshaded irradlance 1600 uEm see FAR
-------
Plant Growth
Soybean growth after seven weeks of treatment was affected both by PAR
level and UV-B flux (Table 7). Biomass production declined linearly with
decreasing PAR levels during growth. UV-B fluxes up to 1 UV-B had little
seu
affect on total plant biomass, particularly at high levels of PAR during
growth. However. 2 UV-B treatments resulted in reduced total biomass
6 seu
accumulation at all PAR levels (Figure 16a). This trend was also reflected
in biomass allocation to leaves, stems and roots (Figures 16.b, c and d).
The total leaf area varied indirectly with UV-B enhancement and was a
good indicator of total plant biomass production. In control soybeans
approximately the same total leaf area was maintained in shade levels between
0 and 55% (Figure 17a). Total leaf area was significantly (P < 0.05) reduced
in shade treatments below 55%. Soybeans exposed to 1/2 UV-B had leaf area
seu
reductions in PAR irradiances less than 33% shade. Greater UV-B fluxes re-
sulted in a leaf area reductions in irradiances less than full sun. Therefore,
total leaf .area was more responsive to light-limiting leaf area reductions
when exposed to UV-B.
When biomass was partitioned into leaves, stems and roots and expressed
as a percentage of total dry weight, significant interaction terms were
resolved, indicating the complex nature of these responses (Table 7). Percent
leaves in soybeans grown under moderate to high levels of PAR was unaffected
by UV-B fluxes up to 1 UV-B (Table 8). Below shade levels of 55%, leaves
of the controls were significantly (P < 0.05) reduced compared with soybean
exposed to UV-B radiation (Figure 17d). However, under high to moderate
PAR levels, 2 UV-B resulted in a significantly (P < 0.05) greater leaf
production. This shift in allocation patterns was most evident in soybeans
V-49
-------
Table
Sunmary of 2 way ANOVA on the effects of 4 UV-B irradiances and 4 levels of PAR on soybean and wheat growth
and blooass accumulation.
soybean
f
Total leaf area (CD )
Total no. leaves
Leaf dry wt (g)
Root dry wt (g)
Stem dry wt (g)
Inflorescence dry wt (g)
Specific leaf thickness (g)
Total dry wt biomase (g)
Root-shoot ratio
Z stems
Z roots
Z leaves
Z Inflorescences
Index of chlorosis
Index of wrinkling
UV-B
df
3
3
3
3
3
3
3
3
3
3
3
4
6
2
3
3
8
2
22
18
22
108
F
.55**
.10***
.10ns
.57**
.08*
.09***
.74*
.65***
.08***
.17***
.08***
df
3
3
3
3
3
3
3
3
3
3
3
PAR
UV-BxPAR
F
24.
127.
37.
75.
29.
21.
40.
328.
166.
301.
47.
74***
72***
47***
76***
28***
75***
53***
40***
58***
31***
66***
df
9
9
9
9
9
9
9
9
9
9
9
1.
14.
0.
0.
0.
13.
0.
11.
6.
12.
23.
F
92*
07***
64ns
71na
74ns
17***
55ns
17***
16***
36***
,72***
wheat
UV-B PAR UV-Bx PAR
df F df F df F
3 6.75**ป 3 90.33*** 9 5.65***
3 8.70*** 3 228.79*** 9 4.33***
3 8.98*** 3 133.66*** 9 3.69***
3 39.21*** 3 397.17*** 9 16.63***
3 111.79*** 3 690.45*** 9 27.37***
3 24.10*** 3 349.25*** 9 9.03***
3 92.17*** 3 820.90*** 9 27.34***
3 39.96*** 3 273.53*** 9 13.66***
3 45.26*** 3 313.25*** 9 14.43***
3 113.33*** 3 494.90 9 27.57***
3 34.53*** 3 98.22*** 9 21.65***
3 101.82*** 3 0.23ns 9 2.29ns
3 90.27*** 3 1.67ns 9 i.36ns
-Soybeans harvested after 50 days UV-B exposure
Wheat harvested after 43 days UV-B exposure
* - significant at P< 0.05
** - significant at P<0.01
*** significant at P< 0.001
na - not significant
-------
Figure 16. Effects of four UV-B irradiances and four PAR levels on total
plant biomass accumulation (XTOTDWT), stem dry weight (XDv>ETEM),
root dry weight (XDWROOT), and leaf dry weight (XDWLF) in soy-
beans after seven weeks. Means expressed in grains are plotted
for each variable against level of shade (PAR) in which plants
were grown. Oomshaded, 3=33% shade, 5=55% shade, and 8=88%
shade. Average maximum daily unshaded irradiance=1600
-2-1
uE m sec PAR. Each mean is based on 9 observations. Numbers
in each curve represent UV-B irradiances. 0=mylar control, 5=
% UV-B , 1=1 UV-B , 2=2 UV-B . Vertical bars
seu' seu' seu
connect curves that are not significantly different at the
95% level.
v-51
-------
XTOTCfcT
S
XDWROOT
2.1
1.3
l.S
1.2
0.9
0.6
0.3
0.0
2 46
. PAR
A
XOViETEN
2.8
2.4
2.0
1 .6
1.2
0.3
0. 4
0.0
XDปLF
3.5
3.0
2.5
2.0
1 . S
1 .0
0.5
0.0
PAR
B
D
4
PAR
6
.0.
4
PAR
-------
Figure 17. Effects of four UV-B irradiances and four PAR levels on leaf
areas (XLFAREA), % steins (XPCSTEM), % roots (XPCRDOT), and
% leaves (XPCLF) in soybeans after seven weeks. Leaf areas are
9
expressed in on . Means for each variable are plotted against
level of shade (PAR) in which plants were grown. 0=unshaded,
3=33% shade, 5=55% shade, and 8=88% shade. Average maximum.
-2-1
daily unshaded irradiance=1600 uE m sec PAR. Each mean is
based on 9 observations. Numbers in each curve represent UV-B
irradiances. CHiylar control, 5=% UV-B . , 1=1 UV-B
J ' * sen' seu,
2=2 UV-B. . Vertical bars connect curves that are not
seu
significantly different at the 95% level..
V-53
-------
XLFARE*
1400
1200
1000
800
600
400
200
A
XPCRCOI
0.30
0.27
0.24
0.21
0. 18
0.15
0.12
0.09
2 4
PAR
c
XPCSTEK
0. 48
0. 44
0.40
0.36
0.32
XPCLF
0.48
0.44
0.40
0.36
0.22
4
PAH
4
PAR
4
PAR
-------
Table 8
Mean effects of A UV-B irradlaneos and 4 shade levels on soybean growth and bionass accunulatIon after 7 weeks of exposure. Data la
parenthesis are expressed as percent of nylor control.
Ui
Ln
2 '
Shade
UV-B
0
1034.22
Leaf area (en )
Total no. leaves
Leaf dry wt (g)
Root dry wt (g)
Stem dry wt (g)
Specific leaf .
thickness (gdm )
Total dry wt biomass (g)
Root-Shoot ratio
Z Stem
Z Root
Z Leaf
Index of Chlorosis
Index of wrinkling
^Harvest after 50 days UV-B
a3
20.5
a
2.81
a
1.91
a
2.45
a
.00275
a
7.18
a
0.39
a
32.4
b
28.2
a
39.4
b
0.11
b
1.11
b
Z
lj
1170.11
a
(113.2)
19.75
a
(96.3)
2.78
a
(98.9)
1.77
a
(92.7)
2.69
a
(109.8)
.00234
c
(85.1)
7.24
a
(100.8)
0.36
b
(92.3)
34.6
flb
(106.8)
26.1
b
(92.6)
39.2
b
(99.5)
1.44
b
(14.4)
1.44
b
(14.4)
- 0
1 2
1146.10 997.46
a a
(110.8) (94.4)
21.25 19.5
a a
(103.7) (95.1)
3.04 2.50
a a
(108.2) (89.0)
1.97 1.37
a a
(103.1) (71.7)
2.67 2.32
a a
(109.0) (94.7)
.00255 .00236
b c
(92.7) (85.8)
7.68 6.20
a a
(107.0) (86.4)
0.39 0.31
ab c
(100.0) (79.5)
32.7 35.1
b a
(100.9) (108.3)
27.7 23.8
ab c
(98.2) (84.4)
39.6 41.1
b a
(100.5) (104.3)
5.13 4.67
a a
(51.3) (46.7)
3.38 4.00
a a
(33.8) (40.0)
0
1182.12
a
20.0
b
1.86
a
0.62
ab
2.02
ab
.00157-
c
4.49
ab
0.19
b
42.8
a
15.8
b
*il.3
b
0.11
b
1.06
b
exposure
^Expressed as percent incident radiation shaded. (lean daily
Values In rows under each
level
of shade
unshaded
Z - 33
4 1 2
Z - 55
0 *j
1272.3 829.0 775.75 1131.49 806.77
a a a
(107.6) (70.1) (65.6)
20.75 17.75 23.5
b c a
(103.8) (88.8X117.5)
2.42 1.91 1.54
n a a
(130.1X102.7) (82.8)
0.91 0.93 0.38
a a b
(146.8X150.0) (61.3)
2.39 1.79 1.26
a ab b
(118.3) (88.6) (62.4)
.00186 .00214 .00202
baa
(118.5)(136.3)(128.7)
5.72 4.63 3.19
a ab b
(127.4X103.1) (71.0)
0.23 0.25 0.15
a a c
(121.0(131.6) (78.9)
39.1 37.5 37.6
b b b
(91.4) (87.6) (87.9)
18.5 20.2 13.0
a a c
(117.1X127.8) (82.3)
42.5 42.2 49.4
b b a
(102.9X102. 2X119. 6)
1.06 5.33 4.00
baa
(10.6) (53.3) (40.0)
1.19 4.28 5.11
baa
(11.9) (42.8) (51.1)
a a
(71.3)
19.25 18.0
ab b
(93.5)
1.60 1.18
a ab
(73.8)
0.45 0.28
a b
(62.2)
1.68 1.28
a a
(76.2)
00141 .00149
c c
(105.7)
3.74 2.74
a a
(73.3)
0.17 0.14
ab b
(82.4)
43.99 45.2
a a
(102.8)
14.47 12.1
ab b
(83.6)
41.54 42.6
b b
(102.6)
0 0
c c
(0)
0 0.78
c c
(7.8)
1
762.71
a
(67.4)
20.25
a
(105.2)
1.48
a
(92.5)
0.51
n
(113.3)
1.47
a
(87.5)
.00183
b
(129.8)
3.46
a
(92.5)
0.20
a
(117.6)
41.1
b
(93.4)
16.3
a
(112.6)
42.6
b
(102.6)
4.00
b
(40.0)
4.17
b
(41.7)
2
295.68
b
(26.1)
13.25
c
(68.8)
0.62
b
(38.8)
0.14
b
(31.1)
0.54
b
(32.1)
.00222
a
(157.4)
1.30
b
(34.8)
0.14
b
(82.4)
38.7
c
(88.0)
12.6
b
(87.1)
48.7
a
(117.2)
6.39
a
(63.9)
6.11
a
(61.1)
0
45.93
b
7.75
b
0.12
b
0.06
b
0.16
b
.00333
a
0.34
b
0.22
. a
47.74
a
17.94
a
34.31
b
0
b
0
c
Z - 88
*5 1
489.8 385.87
a a
(1066. 4) (840.1)
13.25 15.0
a a
(171.0)(193.5)
0.72 0.64
a a
(600.0X533.3)
0.16 0.14
a a
(266.7X233.3)
0.76 0.62
a a
(475.0X387.5)
.00148 .00171
b b
(44.4) (51.4)
1.64 1.40
a a
(482.4X411.8)
0.11 0.11
b b
(50.0) (50.0)
46.2 44.1
a b
(96.8) (92.4)
10.0 10.2
b b
(55.7) (56.9)
43.8 45.7
a a
(127.7X133.2)
1.00 4.33
b a
(10.0) (43.3)
0.78 3.44
c b
(7.8) (34.4)
2
168.42
b
(366.7)
10.25
b
(132.3)
0.31
b
(258.3)
0.08
b
(133.3)
0.29
b
(181.3)
.00189
b
(56.8)
0.68
b
(200.0)
0.14
b
(63.6)
42.8
b
(89.7)
12.0
b
(66.9)
45.2
a
(131.7)
4.89
a
(48.9)
4.78
a
(47.8)
-2 1
naxlnum - 1600 uEra sec PAR
with the same letter are not significantly different
IAM n art A Q
at the 95Z level
-------
grown under shade levels between 33 and 55% where nearly 50% of the total
biomass was found in leaves compared with 40% in the mylar controls. At the
lowest PAR level, all three UV-B treatments resulted in a significantly
(P < 0.05) greater allocation to leaf production.
In high to moderate PAR levels; 2 UV-B. resulted in a reduction in the
seu
proportion of dry weight allocated to roots as compared to the controls
(Figure 17c). A greater proportion of dry weight accumulated in roots of
soybeans exposed to moderate PAR levels and up to the 1 UV-B treatment.
r seu
This shift in allocation was at the expense of stems rather than leaves.
However, under lower PAR levels, all three UV-B treatments resulted in a
reduced root biomass when compared with controls.
Biomass accumulation in stems responded somewhat differently from leaves
and roots (Figure 17b). Only under full sunlight did UV-B treatment result
in an increase in allocation to stem dry weight. Under all other reduced
PAR levels, UV-B treatment resulted in a reduction in stem tissue.dry weight.
Therefore, under high PAR levels and 2 UV-B exposure, biomass was reduced
seu
in roots and allocated to stems and leaves. In moderate PAR levels, more
biomass was allocated from stems to leaves. Under the lowest PAR level,
biomass from stems and roots both were allocated to leaves.
These biomass allocation patterns were also reflected in root-shoot
ratios (Table 8). In high to moderate PAR regimes, up to 1 UV-B had little
Sell
effect. However, 2 UV-B treatments resulted in a significant (P < 0.05)
SGU
reduction in the root-shoot ratios. In moderate PAR levels and low UV-B
fluxes, more dry weight was allocated to roots than shoots. However, when
soybeans were grown in low PAR levels any exposure to UV-B resulted in a
considerable reduction in the root-shoot ratios compared with the mylar
control.
V-56
-------
Two index values, leaf chlorosis and leaf interveinal wrinkling were
used to visually assess the UV-B flux-related damage. Both of these indices
were independent of PAR, and 'directly related to UV-B flux (Table 8). As
shown in Figures 18a and b, these indices were good indicators of the amount
of UV-B received by soybeans regardless of PAR level. These figures also
indicated that soybean sensitivity to UV-B greatly increased between 1/2 and
1 UV-B exposure, possibly suggesting a threshold effect.
S C- UL
The effects of UV-B on soybean growth in terms of plant height are shown
in Table 9. With the exception of week 4, soybeans maintained a greater
growth rate in full sunlight when exposed to some level of UV-B. In this
high PAR regime, however, there were no consistent differences between UV-B
fluxes. As PAR levels were reduced to 33 and 55% of incident radiation,
simultaneous exposure to UV-B resulted in a reduction in growth rates. In
general, the amount of reduction was directly related to the UV-B flux. When
PAR was further reduced to 88% shade, soybeans again maintained higher growth
rates when exposed to UV-B.
As presented in Table 7 the responses of wheat to a combination of
4 UV-B flux levels and 4 PAR levels was much more complex than that of soy-
bean. All of the growth variables examined were associated with highly
significant (P < 0.001) interactions between UV-B irradiance and PAR. Effects
on wheat growth as indicated by biomass accumulation after six weeks exposure,
are shown in Figure 19A. The greatest UV-B associated biomass differences
were found in the high irradiance (unshaded PAR regimes). These differences
diminished as PAR was reduced, but were still evident in wheat grown in 88%
shade.
Wheat exposed to 1 UV-B accumulated a significantly (P < 0.05) greater
ot-U
dry weight biomass in all 4 PAR regimes (Table 10). In the control wheat
V-57
-------
Figure 18. Effects of four UV-B irradiances and four PAR levels on indices
of leaf chlorosis (XCHLORO) and interveinal wrunkling (XWRINK)
in soybean after seven weeks. Indices range from 0 to 9 (see
Table 2) and are plotted against level of shade (PAR) in which
plants were grown. 0=unshaded, 3=33% shade, 5=55% shade, and
8=88% shade. Average maximum daily unshaded irradiance=1600
-2 -1
uE m sec PAR. Each mean is based on 9 observations. Numbers
in each curve represent UV-B irradiances. 0=mylar control,
5=% UV-B , 1=1 UV-B , 2=2 UV-B . . Vertical bars
seu' seu seu
connect curves that are not significantly different at the
95% level.
V-58
-------
XCHLCPC
7
PAR
XhfiINK
7
B
PAR
V-59
-------
Table 9
Mean effects of 4 UV-B Irradlances and 4 shade levels on soybean and wheat growth rates. Data in parenthesis are expressed
as percent nylar control.
UV-B
seu
Soybean growth (nm-day~ )
Week 2
Week 3
Week 4
Week 5
Week 6
Wheat growth (on-day" )
Week 2
Week 3
Week 4
Week S
Shade1
0
6.34
' c2
3.83
b
24.73
a
4.34
b
14.77
b
6.45
a
7.07
a
20.98
b
8.64
a
* -
*!
8.08
b
(127)
5.70
ab
(149)
23.36
a
(94)
23.46
a
(541)
26.05
ab
(176)
4.47
b
(69)
9.04
n
(128)
23.96
a
(111)
10.32
a
(119)
0
1
8.16
b
(129)
4.88
ab
(127)
18.55
a
(75)
16.61
a
(383)
18.77
a
(127)
6.57
a
(102)
9.19
a
(130)
22.12
ab
(105)
8.23
a
(95)
2
11.49
a
(181)
6.52
b
(170)
22.54
a
(91)
20.71
a
(477)
24.31
a
(165)
7.25
a
(112)
6.95
a
(98)
21.76
ab
(104)
9.96
a
(115)
0
31.49
a
28.48
a
44.34
a
59.11
a
44.55
a
6.04
a
5.51
b
20.86
a
12.12
a
Z
j
22.29
b
(71)
18.52
b
(65)
24.04
a
(54)
49.82
a
(84)
48.30
a
(108)
5.86
a
(97)
7.16
ab
(130)
18.60'
a
(89)
13.69
a
(113)
33
1
17.11
c
(54)
10.95
c
(38)
31.98
a
(72)
26.43
b
(45)
29.12
ab
(66)
7.09
a
(117)
7.88
ab
(143)
20.06
a
(96)
9.46
a
(78)
2
16.74
c
(53)
13.80
be
(4R)
29.31
a
(66)
22.04
b
(37)
16.91
b
(36)
6.61
a
(109)
8.77
a
(160)
16.58
a
(80)
12.79
a
(106)
0
36.40
a
27.72
a
50.62
a
42.14
a
50.80
a
5.27
b
7.09
a
15.14
a
12.07
a
Z
*>
35.62
a
(98)
24.23
a
(87)
39.71
a
(78)
40.45
a
(96)
51.18
a
(101)
8.11
a
(154)
3.83
b
(54)
19.82
a
(131)
9.74
a
(81)
55
1
24.59
b
(68)
16.20
b
(58)
34.59
ab
(68)
31.07
a
(74)
17.34
a
(34)
6.32
ab
(120)
8.20
a
(116)
12.60
a
(83)
18.52
a
(153)
2
15.74
c
(43)
9.99
b
(36)
21.86
b
(43)
24.75
a
(59)
26.14
a
(51)
5.71
b
(108)
0.17
c
(2)
15.36
a
(101)
10.36
a
(86)
0
4.56
c
1.77
c
0.09
c
6.68
b
15.1'
a
5.38
b
0.81
a
0.49
c
7.62
a
Z
*ป
31.48
a
(690)
20.07
a
(1134)
47.55
a
(52833)
20.82
ab
(312)
41.02
a
(271)
8.97
a
(167)
0.98
a
(121)
7.13
ab
(14455)
12.57
a
(165)
88
1
26.42 .
ab
(579)
16.53
ab
(934)
31.07
ab
(34522)
33.96
a
(508)
17.57
a
(116)
7.20
ab
(134)
0.26
a
(32)
9.62
a
(1963)
10.01
a
(131)
2
21.68
b
(475)
10.48
b
(592)
16.82
cb
(18689)
16.50
ab
(247)
6.18
a
(41)
7.81
ab
(145)
0.58
a
(72)
3.23
be
(659)
7.94
a
(104)
.Expressed' as percent incident irradiance shaded. Mean daily maximum unshaded irradianee 1600 uEnT aec~ PAR
Values in rows under each shade level with the sane letter arc not significantly different at the 95Z level.
-------
Table in . Mean effecto of 4 UV-B irradiances and 4 shade levels on wheat blonass accunulatton after 6 veeks exposure. Data In parenthesis
expressed as percent of nylor control.
Shade
Z 0
UV-B
seu
Leaf area (en )
Tocal leaves
Root dry wt (o)
Leaf dry wt (c>
Inflorescence dry
wt (g)
: Total dry wt (g)
"f Specific leaf
CF> ' thickness (g>cm~ )
"^ \
] Root-shoot ratio
: Z yellov leaves
Z Inflorescence
* b
Z root
Z leaf
0
233.46
abJ
45.3
a
1.25
a
2.81
ob
0.52
ab
4.57
a
0.0113
. 0.479
a
70.83
a
6.90
n
31.49
a
61.54
c
ปl
206.33
b
(88.40)
37.0
b
(83.66)
0.72
b
(57.60)
1.93
c
(70.46)
0.25
b
(40.08)
2.94
b
(64.33)
0.0090
(79.65)
0.390
be
(81.42)
S2.05
b
(73.49)
4.7!)
a
(68. 4U)
27.17
be
(06.31)
68.05
a
(110.53)
1
283.30
a
(121.60)
45.1
a
(99.56)
1.17
A
(93.60)
3.01
a
(107.12)
0.61
a
(117.31)
4.78
a
(104.60)
0.0101
(,
(00.38)
0.411
ab
(05.00)
70.54
a
(99.59)
7.42
n
(106.30)
28.46
nb
(90.41)
64.12
b
(104.19)
2
232.44
ab
(99.56)
37.2
b
(32.12)
0.65
b
(52.00)
2.20
be
(73.29)
0.39
ab
(75.00)
3.24
b
(70.90)
0.00fl9
(7.1.76)
0.322
b
(67.22)
72.03
a
(101.69)
7.42
a
(106.30)
23.69
c
(75.25)
63. (19
a
(111.94)
0
151.06
b
23.7
c
0.16
c
0.97
c
0.03
b
1.22
c
0.0061
t,
0.193
b
39.68
b
4.69
a
15.76
b
79.55
a
Z
l
230.13
c
(152.34)
27.1
b
(114.35)
0.28
b
(175.00)
1.45
b
(149.48)
0.18
b
(225.00)
1.91
b
(156.56)
0.0062
b
(101.64)
0.208
b
(107.77)
58.49
a
(147.40)
6.37
a
(135.32)
16.81
b
(106.66)
76.82
b
(96.57)
33
1
227.2
a
(150.40)
30.8
a
(129.96)
0.52
a
(325.00)
1.35
a
(190.72)
0.30
a
(375.00)
2.67
a
(218.85)
0.0078
(127.87)
0.306
a
(158.55)
59.91
a
(150.98)
7.35
a
(156.72)
22.22
a
(140.99)
70.43
c
(88.54)
2
238.16
a
(157.66)
28.2
b
(118.99)
0.27
b
(168.75)
1.55
ab
(159.79)
0.18
b
(225.00)
2.00
b
(163.93)
0.0063
b
(103.28)
0.192
b
(99.48)
58.01
a
(146.19)
5.96
a
(127.08)
15.71
b
(99.68)
78.33
ab
(98.47)
.Harvested after 43 days of exposure . _, ,
'Expressed as percent Incident radiation shaded. Mean daily unshaded naxinua ซ 1600ijEn~~eoc PAR
Values in rows under each level of shade followed by the sane letter arc not significantly different at the 957, level
-------
Table 10 ... Jlean effects of 4 UV-
cont. expressed as percent
'B Irradiance8 and 4 shade levels on wheat blonass accumulation after
of mylar control.
Shade2
6 weeks exposure. Data In parenthesis
^"seu
2
Leaf area (CD )
Total leaves
Root dry wt (g)
Leaf dry wt (g)
Inflorescence dry
wt (g)
Total dry vt (g)
1
ON Specific leaf .
fฐ thickness (g-cm )
Root-shoot ratio
Z yellow leaves
: Z Inflorescense
Z root
Z leaf
0
195.46
a
25.6
a
0.22
1)
1.17
ab
0.11
b
1.50
b
0.0059
b
0.204
b
40.84
b
4.79
a
16.56
b
78.65
b
Z
h
157.68
b
(80.67)
24.3
a
(94.92)
0.18
be
(81.82)
0.97
b
'(82.91)
0.08
be
(72.73)
1.23
b
(82.00)
. 0.0059
b
(100.00)
0.220
b
(107.84)
43.29
b
(106.00)
4.30
a
(89.77)
17.38
b
. (104.95)
78.31
b
(99.57)
55
1
174.1
ab
(89.07)
25.0
a
(97.66)
.36
a
(163.64)
1.31
a
(111.97)
.20
a
(181.82)
1.87
a
(124.67)
0.0070
a
(118.64)
0.292
a
(143.14)
41.51
b
(101.64)
6.43
a
(134.24)
22.00
a
(132.85)
71.57
c
(91.00)
2
113.35
c
(57.99)
24.4
a
(95.31)
.13
c
(59.09)
0.71
c
(60.68)
.02
c
(18.19)
0.86
c
(57.33)
0.0061
b
(103.39)
0'.222
b
(108.82)
68.33
a
(167.31)
1.70
b
(35.49)
17.53
b
(105.86)
80.77
n
(102.70)
0
54.52
c
18.2
b
0.03
b
0.27
b
0
c
--
0.36
b
0.0055
a
0.366
ab
67.67
a
0
a
-_
25.70
a
74.30
b
Z
**
105.23
a
(193.01)
18.9
ab
(103.85)
0.11
a
(137.50)
0.52
a
(192.59)
0
a
-_
.622
a
(172.78)
0.0048
b
(87.27)
0.266
b
(72.68)
34.61
b
(51.15)
0
a
20.30
b
(78.99)
79.70
a
(107.27)
- 88
1
115.04
a
(211.01)
21.9
a
(120.33)
0.11
a
(137.50)
0.55
a
(203.70)
0
a
--
0.66
a
(183.33)
0.0048
b
(87.27)
0.216
b
(59.02)
41.96
b
(62.01)
0
a
17.40
b
(67.70)
82.60
a
(111.17)
2
77.52
b
(142.19)
17.78
b
(97.69)
.07
b
(87.50)
.33 '
b
(122.22)
0
a
~
.40
b
(111.11)
0.0042
c
(76.36)
0.504
a
(137.70)
41.82
b
(61.80)
0
e
26.20
a
1 (101.95)
73.80
b
(99.33)
.Harvested after 43 days of exposure . . _.
.Expressed as percent incident radiation shaded. Mean dally unshaded maximum 16uEn" sec" FAR
Values In rows under each level of shade followed by the sane letter arc not significantly different at the 95Z level
-------
(mylar) nearly all the biomass reduction occurred between the unshaded and 33%
shade treatments. Biomass remained constant in PAR levels below 33% shade.
However, in wheat exposed to UV-B, dry weight reduction was nearly linear
with decreases in PAR. Similar trends were noted for dry weight accumulation
into leaves, roots and inflorescences (Figures 19B, C and D).
The difference in dry weight accumulation between UV-B treatments was
reflected in the total leaf number and, to a lesser extent, the total leaf
area (Figures 20A and B). Where significant, both total number of leaves and
leaf area were greatest when plants x^ere exposed to 1 UV-B . In these
S6U
plants, the proportion of total biomass allocated to leaves increased as the
PAR level incident during growth was reduced (Figure 21A). When wheat was
unshaded and grown under 1 UV-B , leaves accounted for 62% of the total dry
seu
weight. However, when grown in 88% shade, 82% of the total biomass was
allocated to leaves. Wheat exposed to 1/2 UV-B also increased allocation
seu
to leaves as PAR was reduced, however, at a lower rate. Wheat grown both
under the mylar and 2 UV-B resulted in maximum biomass allocation to leaves
seu
in intermediate PAR levels. Under 88% shade, percent leaves declined under
these UV-B conditions.
Wheat exposed to 1 UV-B and PAR levels between unshaded and 55% shade
seu
resulted in a significant (P < 0.05) reduction in the percent total biomass
allocated to leaves compared with the mylar control and the other UV-B
treatments. However, at PAR levels below this, these plants maintained a
larger portion of biomass in leaves.
Dry weight accumulation into roots was very different from that of
leaves (Figure 21B). More dry weight was partitioned into roots at high
and very low PAR regimes when plants were exposed to 1/2 and 2 UV-B t>r
seu
when grown under mylar. Under these conditions, roots accounted for 20 to
V-63
-------
Figure 19. Effects of four UV-B irradiances and four PAR levels on total
plant dry weight (XK1TDWT) , leaf dry weight (XDWLF) , root dry
weight (XDWRDOT) , and inflorescence dry weight (XDWFL) in wheat
after six weeks . Means expressed in grains are plotted for each
variable against level of shade (PAR) in which plants were
grown. 0=unshaded, 3=3370 shade, 5=55% shade, and 8=88% shade.
-2 -1
. Average maximum daily unshaded irradiance=1600 uE m sec PAR.
Each mean is based on 9 observations . Numbers in each curve
represent UV-B irradiances. CHmylar control, 5=% UV-B ,
, S G U-
1=1 UV-B " ,.2=2 .UV-B . Vertical bars connect curves
S fc- vi
that are not significantly different at the 9570 level.
V-64
-------
f
XTOTOVil
5.6
4.3
4.0
3.2
2.4
1 .6
o.a
0.0
XCWPCOT
1.4
1.2
1.0
O.S
0.6
0.4
0.2
0.0
c
XChLF
3.2
2.8
2.4
2.0
1.6
1.2
O.S
0.4
XDfcFL
'C.7
O.6
0.5
0.4
0.3
0.2
0. 1
0.0
4
PAR
B
D
/7
4
PAR
PAR
-------
Figure 20. Effects of four UV-B irradiances and four PAR levels on total leaf
production or number (XTOTLVS) and total leaf area (XLFAREA)
2
in wheat after six weeks . Leaf areas are expressed in cm .
Means for each variable are plotted against level of shade (PAR)
in which plants were grown. Ounshaded, 3=337, shade, 5=557ป
shade, and 8=8870 shade. Average maximum daily unshaded
-2 -1
irradiance=1600 uE m sec PAR. Each mean is based on 9
observations. Numbers in each curve represent UV-B irradiances.
0=mylar control, 5=% UV-Bseu> 1=1 UV-B^-, 2=2 UV-Bseu.
Vertical bars connect curves that are not significantly different
at the 957, level.
V-66
-------
XTOTLVS
44
40
36
32
28
24
20
16
320
280
240
200
160
120
80
40
4
PAR
A
B
-4-
2 4
PAR
V-67
-------
Figure 21. Effects of four UV-B irradiances and four PAR levels on %
leaves (XPCLF), % roots (XPCRDOT), % inflorescences (XPCEL),
and specific leaf thickness (XDEN) in wheat after six weeks.
-2
Specific leaf thickness is expressed in g-cm . Means for each
variable are plotted against level of shade (PAR) in which
plants were gram. 0=unshaded, 3=3370 shade, 5=55% shade, and
8=88% shade. Average maximum daily unshaded irradiance=1600
-2 -1
uE m sec PAR. Each mean is based on 9 observations. Numbers
in each curve represent UV-B irradiances. 0=mylar control,
'5=% UV-B , 1=1 UV-B , 2=2 UV-B . . Vertical bars
seu' seu' seu
connect curves that are not significantly different at the
95% level.
68
-------
f
CT>
VO
XPCLF
0.88
0.64
O.80
0. 76
0. 72
o.ee
0.64
0.60
XPCFL
0.08
0.06
0* 04
0*02
0.00
4
PAR
XFCBC01
0.2S
0.28
0.24
0.20
0.16
XOEN
0.012
0.010
0.008
0.006
0.004
B
4
PAR
D
s.\
PAR
4
PAR
-------
30% of the total dry weight. However, under intermediate PAR levels, only
about 16% of the total dry weight was found in roots. Wheat plants exposed
to 1 UV-B again resulted in very different responses. In these plants,
percent roots declined linearly with decreasing PAR.
Percent flowers (or reproductive effort) varied inversely with PAR
level, and was light limited in 88% shade (Figure 21C). The percent total dry
weight allocated to flowers was greatest in wheat plants exposed to 1
UV-B irradiance at all PAR levels, although not significantly so. At low
seu >oo
PAR levels, wheat grown under 2 UV-B resulted in a significantly (P < 0.05)
SGU
reduced reproductive effort.
Specific leaf thickness was significantly (P < 0.05) greater for control
wheat leaves compared to leaves exposed to UV-B radiation .when grown under
unshaded conditions (Figure 21D) . In shade levels greater than 33% shade,
leaf thickness in control plants were unaffected by further PAR reductions.
Specific leaf thickness was greater in wheat plants exposed to 1 UV-B
S GU
compared to 1/2 and 2 UV-B exposures throughout the PAR range employed.
v
The effects of UV-B on wheat growth are presented on Table 9. Unlike
soybean, there were no consistent UV-B associated effects on wheat growth
rates among or between PAR levels.
Discussion
Gas Exchange Data
The growth of 'Hardee1 soybeans in a combination of 4 flux levels of
UV-B radiation and 4 PAR flux levels demonstrated the importance of plant
interactions as related to UV-B and to longer wavelength radiation. When
soybeans were exposed to UV-B and grown under unshaded (high PAR) levels,
V-70
-------
there was no UV-B associated reduction in NCE. However, as the PAR level was
reduced, increasing UV-B enhancements did result in significant NCE reduc-
tions. In shaded conditions, NCE varied inversely with UV-B flux.
This reduction in NCE was primarily due to increased non-stomatal resis-
tances, Rr , particularly at reduced PAR levels. Therefore the effect of
LtU~
UV-B must act on some other component of the photosynthetic apparatus, besides
resistances to stomatal diffusion. Previous evidence indicates that UV
radiation exposure results in an inhibition of photosystem II (PSII) and
to a lesser extent photosystem I (PSI) (Brandle j^t a.1 . , 1977; Okada et al . ,
1976; Mantai e_t a^. , 1970; and Zill and Tolbert, 1958). This may be associated
with UV-B induced disruption of the structural integrity of the lamellar
membrane systems in the chloroplasts (Brandle et^ a^. , 1977; Campbell, 1975;
Mantai jit _al_. , 1970). In the present study, total leaf protein was not
affected by UV-B treatment. However, total chlorophyll and chlorophyll a/b
ratios were generally greater in soybean plants exposed to 1 UV-B
seu
Both proteins and nucleic acids are major chroma tophores for UV-B induced
damage in biological systems. The most important biological effect of UV-B
to DNA is the formation of the pyrimidine dimer. UV-B induced dimerization can
be reversed by a mechanism called photoreactivation. This repair mechanism re-
stores normal cellular functions and is dependant upon the action of photo-
reactivating enzymes and radiation of longer wavelength (315-550 nm) .
Evidence indicates that a large number of other physiological manifestations,
including UV-B associated reductions in NCE, are also photorepairable (Sisson
and Caldwell, 1976; Van ฃt al. , 1976; Cline _et al^. , 1969; Tanada and
Hendricks, 1953). The data presented here tended to support this hypothesis.
ป
Under high PAR levels, photorepair of NCE was nearly complete for the range
of UV-B fluxes tested. However, as light became more limiting both to NCE
V-71
-------
and photorepair, the effectiveness of this repair mechanism diminished. This
resulted in a decrease in NCE at reduced PAR levels by UV-B fluxes which were
ineffective at higher. PAR levels.
These findings were somewhat different from those reported by Sisson and
Caldwell (1976) where Rumex patientia was grown under ambient PAR levels in
-2 -1 -2 -1
the field (maximum PAR was 2100 pE m sec ) and 800 and 400 yE m sec
in controlled environmental chambers. Large differences in NCE were noted in
all three of these PAR regimes when compared with controls. However, in that
particular study, the UV-B enhancement corresponded to an ozone depletion of
38%. The equivalent ozone depletion used in this study ranged between 6 arid
25%. Therefore under low PAR growth conditions, the deleterious effects of
UV-B radiation were magnified by the decreasing effectiveness of photorepair,
possibly photoreactivation. After exposure to more intense UV-B fluxes,
photorepair mechanisms were insufficient to prevent damage.
Sisson and Caldwell (1977) extrapolating from their Rumex-based model,
reported that even small UV-B fluxes result in NCE reductions over time due to
reciprocity. In the present study during the first few weeks of exposure of
soybeans to 1/2 UV-B and high PAR levels, NCE rates were enhanced compared
with controls. This increase was primarily associated with reduced stomatal
resistances, R . The nature of this response is not well understood,
co2
and disappeared by the 6th week of exposure. However, it seemed to suggest
that very low UV-B background fluxes may be beneficial during the early stages
of development, possibly while the plant is still not totally independent from
cotyledonary reserves. Additionally, it illustrated that low UV-B fluxes
affected stomatal as well as non-stomatal resistances.
The concepts of. threshold effects and reciprocity (Sisson and Caldwell,
1977) were supported by comparisons of the gas exchange data after two- and six
V-72
-------
weeks. Significant interactions between UV-B radiation and PAR were observed
in NCE,. transpiration, and the associated diffusive resistances after two
weeks of treatment. However, after six weeks of UV-B radiation exposure,
nearly all these interactions disappeared, indicating that soybean response
to the combination of UV-B and simultaneous PAR treatment had been altered.
This indicated that soybeans became more responsive to UV-B radiation after
a threshold accumulation. This was supported by comparisons of NCE rates
expressed as a percent of control after two and six weeks of UV-B radiation
exposure (Figure 22). In general, relative NCE reductions were greater after
six weeks exposure. These reductions in NCE were primarily associated with
increased non-stomatal resistances. The effects of leaf age were not tested,
and may have contributed toward increased leaf resistance.
The data (Figure 22) further indicated that reciprocity occurred at a
reduced rate under reduced PAR levels. Similar UV-B associated reductions in
NCE required a greater UV-B accumulation in full sunlight than in 33 or 55%
shade. This was thought to be attributed to photorepair at high PAR irradiances.
In PAR fluxes below these threshold levels, UV-B exposure may enhance NCE.
Two indices, interveinal leaf wrinkling and leaf chlorosis, also suggested
threshold effects. Up to 1/2 UV-B had no affect on the visual assessment
r seu
of either symptom of UV-B radiation-related damage. However, exposure to 1
or 2 UV-B greatly affected both indices. Although the precise nature of
these morphological responses might be quite complex, they were independent
of PAR, suggesting that they were not photorepairable. Interveinal wrinkling
and leaf chlorosis were observed only when leaves were exposed to UV-B
radiation during early leaf expansion. Fully expanded leaves exposed to very
large UV-B fluxes (up to 4 UV-B ) did not show either manifestation
o " U.
(unpublished data). This could indicate that interveinal wrinkling might be
V-73
-------
Figure 22. Effects of UV-B accumulation on NCE (leaf dry weight basis)
in soybeans exposed to three different shade levels. Log
-2
UV-B accumulation in Wm are plotted along the ordinate
against percent change in NCE from the control. Data includes
measurements made after 2 weeks (Table 4) and 6 weeks (Table
5). Dashed horizontal line indicates no change from control.
Values below line indicate NCE enhancements, above it NCE
reductions.
V-74
-------
60
40
O-unshaded
A33% shade
D55% shade
20
0
-20
_ AX
-0^
1.5
2.0
2.5
3.0
V-75
-------
the result of UV-B effects on cell division or expansion early in leaf
development.
Campbell (1975) found that chloroplasts appeared to be the first organelle
to shox* injury responses when soybean leaves were irradiated with UV-B radiation.
He added that much of the UV-B associated injury was similar to that found in
the final stages of leaf aging. Since leaf chlorosis only appeared in leaves
which had expanded in the presence of a UV-B flux, and not in fully expanded
mature leaves, these data indicated that UV-B might be interfering with normal
proplastid differentiation, rather than an acceleration of leaf senescence.
Transpiration was also affected by the range of UV-B radiation exposures
used. After two weeks exposure, transpiration rates reflected differences in
stomatal resistances, with the highest rates measured in soybeans grown under
1/2 UV-B which also showed NCE enhancement at this time. Both 1 and
seu
2 UV-B treatments resulted in decreased transpiration rates. After a 6
seu
week exposure to UV-B, transpiration rates declined as UV-B fluxes increased.
As reported by others, dark respiration rates were unaffected by UV-B
even after 6 weeks of exposure. It was not clear whether this was due to
complete photorepair of dark respiration even at low PAR irradiances or if
dark respiration was simply unaffected by the UV-B fluxes employed. Sisson
and Caldwell (1976) did report increased respiration rates in Rumex after only
a few days of exposure. However, that study incorporated a much higher UV-B
flux (equivalent to a 33% ozone depletion) and relatively low PAR levels
(800 yE m~2 sec"1).
Comparisons were made of the NCE data for leaves measured in 2 and 21%
0ซ after 6 weeks of UV-B radiation accumulation. The relative rankings of NCE
for plants exposed to contrasting UV-B fluxes differed in 2% 0_ from re'sponses
measured in the same leaves at 21% 0ป. This suggests that photorespiration
V-76
-------
might be affected by UV-B radiation. However, NCE measured in low CL concen-
trations as an estimate of photorespiration relies on many assumptions (see
Ludlow and Jarvis, 1971) and therefore interpretations must be viewed with
caution. Other studies are underway to further elucidate the response of
photorespiration to UV-B.
Plant Growth Data
Plant responses to the combination of UV-B and PAR irradiances differed
between soybean, a UV-B sensitive (Van et^ al^. , 1976; Biggs j2t _al_. , 1975) and
wheat, a UV-B resistant species (Hart j2t_ al . , 1975). In soybeans, total plant
dry weight was unaffected by UV-B irradiances up to 1 UV-3 . However, ex-
posure to 2 UV-B greatly reduced dry weight accumulation. This finding
was consistent with the gas exchange data. UV-B also resulted in shifts in
the total plant biomass allocation pattern. The nature of the shifts was
dependant upon the PAR level incident during growth. In general, exposure
to UV-B radiation resulted in a greater proportion of biomass accumulated in
leaves rather than stems and roots. Therefore, the primary inhibitory effects
of UV-B radiation (vis. NCE reductions) xjere somewhat compensated by the
relative increase in leaf surface area available for photosynthesis. This
was demonstrated both in terms of the total plant biomass accumulation and
total leaf area production. Under 88% shade, biomass and total leaf area of
soybeans in both the 2 UV-B regime and the mylar control were less than
those in the 1/2 and 1 UV-B treatments.
seu
Reduction of NCE by 2 UV-B was partially compensated by increased
seu
leaf area, thereby resulting in a total plant biomass accumulation similar
to that of control soybeans. The increased leaf area in the soybeans ex-
posed to 1/2 and 1 UV-B "over-compensated" for the reduction in NCE, and
V-77
-------
therefore resulted in a greater dry xi/eight accumulation compared to controls.
Under full sunlight, UV-B exposure resulted in stem elongation, as re-
flected in increases in plant height. However, under shaded conditions
stunting associated with UV-B flux was observed.
At low irradiances, wheat growth in terms of dry weight accumulation was
nearly unaffected by UV-B exposure. However, as PAR was increased, UV-B
radiation became an increasingly important factor to the overall plant response.
After a six week exposure to 1 UV-B , biomass accumulation was greater than
S^-vi
that of the mylar control, particularly at intermediate PAR levels. One-half
UV-B exposure became increasingly important at lox^er PAR levels. At the
lowest PAR irradiance, both 1/2 and 1 UV-B resulted in a significant in-
S GU
crease in biomass accumulation compared with wheat grown under mylar or 2
UV-B . These data suggested that in conditions where growth was light-
SGU
limited, the addition of ambient levels of UV-B radiation to the spectral
flux might result in a stimulatory effect on wheat growth.
Under the conditions of this experiment, 1 UV-B resulted in a pattern
seu r
of biomass allocations that was distinct from other UV-B treatments or from
the mylar control. This was consistent over a wide range of PAR levels.
Therefore, the effects of UV-B radiation on wheat were flux density-specific
and resulted in large shifts in carbon allocation as measured by dry matter
accumulation. One of the factors involved was increased tillering in wheat
exposed to UV-B radiation. These data indicated that tillering was greatest
in wheat grown under 1 UV-B and in high to moderate PAR levels. As PAR
S 6U
was further reduced, tillering became more pronounced in wheat grown under
1/2 UV-B
seu
In conclusion we have shoxvn that even low level UV-B enhancements'
(equivalent to only a 6% depletion in stratospheric ozone) had a direct
V-78
-------
effect on NCE. NCE was enhanced by low UV-B fluxes x^hen accumulated below
a minimum or threshold level. Above this level, NCE reductions occurred.
Larger UV-B fluxes were associated with greater reductions. Both stomatal
and non-stomatal diffusive resistances were affected by UV-B radiation.
Stomatal effects were also reflected in transpiration rates.
Photorepair of NCE was ineffective at low PAR levels, but played an
important role in unshaded, ambient situations. In high PAR regimes, photo-
repair was nearly complete in soybeans exposed to fluxes up to 2 UV-B
SGuL
Additionally, our study revealed that the interactions between the flux
densities of UV-B and PAR are complex, and that soybean response to increasing
UV-B fluxes was altered by the flux density of incident radiation available
for photorepair and other photoprotective mechanisms. These differences might
be partly due to modifications within leaves in response to decreasing PAR
levels. Bunce et al. (1977) found that soybean leaves were associated with
large physiological and anatomical shifts during light acclimation. If these
observations are generally applicable, then interpretations of growth chamber .
or greenhouse studies regarding the effectiveness of moderate UV-B enhance-
ments in natural situations must be viewed with caution.
Of all the plant growth and gas exchange variables examined, only two,
indices for interveinal wrinkling and leaf chlorosis were unaffected by PAR.
Fluxes greater than 1 UV-B had a large affect on both indices, even in
6 seu 6
unshaded plants, suggesting that these responses were not photorepairable.
Therefore, both were good indicators of UV-B accumulation, even under a wide
range of PAR levels.
Finally, this study indicated that wheat responds differently from
soybean when exposed to increasing UV-B fluxes. Soybeans underwent shifts
in carbon allocation patterns when exposed to UV-B radiation. The magnitude
V-79
-------
of these shifts was directly related to the UV-B flux density. Two UV-B
seu
resulted in increased allocation to leaves at the expense of all other plant
organs. Wheat on the other hand, demonstrated unique biomass allocation
patterns when exposed to 1 UV-B , indicating more of a flux density-
SGU
specific response. In shaded conditions, UV-B fluxes above or below this
resulted in little change from control. However, in unshaded conditions,
these fluxes resulted in biomass reductions.
The greatest biomass differences between UV-B fluxes occurred in moderately
shaded conditions for soybeans and in full sunlight for wheat. Therefore, PAR
levels incident in greenhouse or growth chambers would provide maximum sensi-
tivity for soybeans, but minimum sensitivity for wheat. This could lead to
spurious interpretations of the effects of UV-B radiation on wheat. This again
underlines the importance of the interaction between UV-B and PAR in under-
standing plant responses.
V-80
-------
Color photographs taken of the UV-B x PAR experiment are included in
Appendix I. The experimental set-up illustrating the use of neutral density
shading materials to obtain the desired PAR levels is shown in 1-35. Mylar
film separate treatments to minimize any UV-B scatter. 1-37 shows the
positioning of the experimental plant material beneath a light fixture
containing 2 FS 40 sunlsmps. Plastic films of either mylar or 3 mil cellu-
lose acetate were used to filter the radiation to the desired spectral
quality and flux.
Representative soybean plants from each treatment are shown in 1-38
after 6 weeks UV-B exposure. Notice that controls (mylar) were shorter
than plants exposed to UV-B in unshaded (100% full sun) conditions, but
that they x\rere tallest in reduced PAR levels. 1-39 illustrates treatment
effects on wheat. Under 45% full sun (5570 shade) only plants which received
2 UV-B. ..did not flower. Note in the two highest PAR levels, plants
SCLI
exposed to 1 UV-B had the greatest tillering. Under lower PAR levels,
SC*-1
greater tillering was found in plants exposed to 1/2 UV-B .
SGX1
Color photographs illustrating leaf chlorosis are presented in 1-35.
The leaf labelled 100 mylar was given an index value of 0 (see Table 2 in
text). 100% 0.5 showed some chlorotic patches and was rated 1. 100% 1
showed much more developed chlorosis (rated index value=5). 100% 2
illustrated a leaf which was entirely chlorotic and leaf margins had begun
to curl (index values=8). Interveinal wrinkling is illustrated in 1^-36.
Both 67% . 5 and 45%, 0.5 showed slight puckering and were rated index
value=l. 4570 1 showed definite puckering and x^as rated as 4. 67% 1.0
illustrated pronounced wrinkling and leaf curl (index value=9) along with
leaf chlorosis. 67% 2 showed bronzing on the leaf surface, which usually
was associated with leaf chlorosis.
V-81
-------
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radiation in early seedling growth and translocation of Zn from cotyledons
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-------
15. Okada, M., M. Kitajima, and W.L. Butler. 1976. Inhibition of photosystem
I and photosystem II in chloroplasts by UV radiation. Plant & Cell Physiol.
17:35-43.
16. Patterson, D.T., J.A. Bunce, R.S. Alberte, and E. VanVolkenburg. 1977.
Photosynthesis in relation to leaf characteristics of cotton from controlled
and field environments. Plant Physiol. 59:384-387.
17. Sisson, W.B. and M.M. Caldwell. 1976. Photosynthesis, dark respiration,
and growth of Rumex patientia L. exposed to ultraviolet irradiance (288-
315 nanometers) simulating a reduced atmospheric ozone column. Plant
Physiol. 58:563-568.
18. Sisson, W.B. and M.M. Caldwell. 1977. Atmospheric ozone depletion:
reduction of photosynthesis and growth of a sensitive higher plant exposed
to enhanced UV-B radiation. J. Exp. Bot. 28(104):691-705.
19. Tanada, T. and S.B. Hendricks. 1953. Photoreversal of ultraviolet effects
in soybean leaves. Amer. J. Bot. 40:634-637.
20. Van, T.K., L.A. Garrard, and S.H. West. 1976. Effects of UV-B radiation
on net photosynthesis of some crop plants. Crop Sci. 16:715-718.
21. Zill, L.P. and N.E. Tolbert. 1958. The effect of ionizing and ultraviolet
radiations on photosynthesis. Arch. Biochem. Biophys. 76:196-203.
V-84
-------
EFFECT' OF ULTRAVIOLET-B ENHANCEMENT ON CUTICLE-
MID EPIDERMAL CELL DEVELOPMENT
From: L.G. Albrigo, AREC, IFAS, Univ. Fl. - Lake Alfred
To: R.H. Biggs, Fruit Crops Dept. IFAS, Univ. Fl. - Gainesville
-------
Materials and Methods
Plant Material
Plants were grown under a high UV light source with mylar, 3 mil
or 5 mil cellulose acetate film filters. Tomato and pepper plants
were grown from seed and blueberry leaves were taken from new shoots
grown under the filtered light sources. One set of tomato and pepper
plants were grown under the light conditions from July 28 through
August 29 or 32 days. Another group of tomato and pepper plants were
grown from September 13 through November 7.
10 Electron microscopy. For transmission electron microscopy (TEM),
11 small sections of young unfolded, newly expanded and mature blueberry,
12 tomato, and pepper leaves were removed with a sharp razor blade in
13 3% glutaraldehyde in 0.2 M potassium phosphate buffer. These were
14 placed in fresh 2% glutaraldehyde in phosphate buffer for 1 hr at
15 room temp (2, 6). The samples were then washed in buffer and post-
16 fixed in 1% OSO in 0.2 M potassium phosphate buffer for 1 hr at room
17 temp or in K_ MnO, for 15 to 30 min (2, 6). Dehydration was done in
18 an acetone series or an ethanol/acetone series (6, 7). The samples were
19 embedded in Spurr's plastic (5).
20 Silver to gold sections were made with a diamond knife on an
21 LKB-Huxley microtome, stained with aqueous 0.5% uranyl acetate for
22 15 min (3), followed by aqueous 0.25% lead citrate .for 5 min (4),
23 and viewed on a Phillips 201 electron microscope at 60 KV.
24 For scanning electron microscopy (SEM), sections (3x3 mm) of
25 mature leaves of tomato and pepper were fixed in glutaraldehyde and
26 osmium (2, 6), dehydrated and critical point dried (1), mounted on
2' __stubs_ and sputter coated with gold-palladium, and. then veiwed on a JEOL
VI-1
-------
1 JMS-35 microscope. Alternatively leaf sections were air dried before
2 mounting and coating to preserve the surface wax structure.
3 Wax analysis. Leaves from the first set of tomato and pepper
4 plants were selected in 2 groups for each treatment and treated as
5 follows: 1) The 1st primary leaves after the cotyledons of pepper
6 plants were used (120 leaves per group) and the oldest 5 leaflet unit
7 of the tomato plants were selected (65 leaves per group). 2) The
8 total leaf area of each group was measured with a Lambda Li-Cor area
9 meter with traveling belt. 3) Each sample was extracted in 2 aliquots
10 (300 ml each) of 60ฐC CHC1. for 1 and 1/2 min, respectively. 4) The
11 dissolved wax for each sample was combined, filtered, dried, and weighec
12 5) The waxes were spotted on 250 ym TLC plates of silica gel at the rate
13 of 5 yl of a 10 mg wax/g CHC1, solution. The plates were developed
14 with benzene:acetic acid (99:1) and Rodamine 6G (.005% aqueous) was
15 used as an indicator spray.
16 Cuticle extractions. Cuticles were excised with ZnCl_:HCl
17 (1:1.7, w:w) using 5 ml per 1 cm diameter leaf disk. An attempt was
18 made to separate these cuticles from the remaining cell debris and
19 leaf vascular system so that cuticle weights and included wax content
20 could be determined.
21 Results and Discussion
22 The higher UV light quality provided by the 3 mil cellulose
23 acetate film filter did not appear to alter the upper leaf epidermis
24 of the 3 plant species studied (Fig. 1). Cell confirmation, chloro-
25 plast location, wall thickness, and cytoplasmic densities as observed
26 by TEM were similar for mature leaves of plants grown under mylar
27 filtered light (Fig. 1 A, C, E) and 3 mil cellulose acetate filtered
VI-2
-------
light (Fig. 1 B, D, F). The younger stages of leaf development also die
not demonstrate differences between treatments. Closer examination of
the surface wax, cuticle, wall structure, and cytoplasm of the mature
leaves of plants grown under mylar filtered light (Fig. 2 A, C, E) and
3 mil cellulose acetate filtered light.(Fig. 2 B, D, F) also did not
reveal any obvious differences in upper epidermal structure.
SEM observation of upper leaf surfaces of tomato and pepper plants
8 did reveal greater numbers of small pebbles of wax or other material
on the mature leaves of plants grown under the 3 mil cellulose acetate
10 film filters (higher UV light) (Fig. 3 B, D and Fig. 4 B, D) than on the
11 leaves of plants grown under mylar film filters (Fig. 3 A, C and
12 Fig. 4 A, C). This material was widely spaced and would not be easy
13 to detect from 0.1 ym thick TEM sections and probably would not affect
14 light penetration into the leaves.
15 Measurement of the total surface wax (Table 1) did not reveal
16 any difference due to treatment on the concentration of surface leaf
17 wax. There was more variation between the 2 replicates of a given
18 treatment than between treatments in most cases. Any trend that might
19 exist would appear to favor more wax on the mylar treatments.
20 The same situation was true for the amount of each individual
21 chemical group of waxes for the tomato (Fig. 5) and pepper (Fig. 6)
22 samples. The tomato wax extracts consistently contained 3 more
23 groups of waxes than the pepper wax extracts (Fig. 5). These were
24 at RF's .03, .06, and .78.
25 The 3 mil cellulose acetate treatment extracts for tomato leaves
26 (Fig. 5) and the mylar treatment extracts for the pepper leaves
27 (Fig. 6) show the variation within treatments.
VI-3
-------
1
2
3
26
27
The cuticles of both tomato and pepper leaves were too fragile
to clean up after digestion of the underlying tissues, and data on
cuticle/unit area and included waxes could not be obtained.
4
Conclusions
5
Except for the SEM evidence of some widely spaced droplets on
6
the surface of leaves of plants from cellulose acetate film filter
7
treatments, no differences were observed between the treatments. These
8
droplets may not have been plant material if somehow the film was
9
shedding these droplets. This might be checked by SEM observation of
10
new and used cellulose acetate film. On the other hand, the lack of
11
response from treatments may have been the result of other stresses,
12'
13
14
15
16
17
18
19
20
21
22
23
24
25
water and heat, masking the UV effect on the 1st set of plants. The
second set which was not as extensively examined had a greater
difference in total growth and necrosis between treatments.
Fig. 1. Adaxial epidermal cell appearance of mature leaves of blueberry
t
(A, B), tomato (C, D), and pepper (E,.F) from plants grown under a i
high UV light source with mylar (A, C, E) or 3 mil cellulose acetate
I
(B, D, F) film filterslow magnification. I
Fig. 2. Adaxial cuticle appearance of mature leaves of blueberry (A", B) ,
tomato (C, D), and pepper (E, F) from plants grown under a high UV
light source with mylar (A, C, E) or 3 mil cellulose acetate (B, D, F)
film filtershigh magnifications.
VI-4
-------
Literature Cited
1. Anderson, T. F. 1966. Electron microscopy of microorganisms. Page
3 319-388 in A. W. Pollister, ed. Physical techniques in biological
4 research: vol. Ill, part A, 2nd ed. Academic Press, New York.
2. Hallam, N. D. 1970. Leaf wax fine .structure and ontogeny in
6 Eucalyptus demonstrated by means of a specialized fixation
7 technique. J. Microsc. 92:137-144.
3. Hayat, M. A. 1972. Basic electron microscopy techniques. Van
Nostrand, Reinhold Co., New York. pp. 119.
10 4. Reynolds, E. S. 1963. The use of lead citrate at high pH as an
11 electron opaque stain in electron microscopy. J. Cell Biol. 17:
12 208-
13 5. Spurr, A. R. 1969. A low-viscosity epoxy resin embedding medium
14 for electron microscopy. J. Ultrastruct. Res. 26:31-43.
15 6. Thomson, W. W. 1966. Ultrastructural development of chromoplasts
16 in Valencia oranges. Bot. Gaz. 127:133-139.
17 7. , L. N. Lewis, and C. W. Coggins. 1967. The
18 reversion of chromoplasts to chloroplasts in Valencia oranges.
19 Cytologia 32:117-124.
20
21
22
23
24
25
26
27
VI-5
-------
Table 1. Surface wax on tomato and pepper leaves of plants grown
under high UV light with.various..film.filters.
Filter for Surface wax
UV light Tomato Pepper
2 2
pg/cm yg/cm
Mylar 4.0, 7.7 7.8, 16.6
5 mil 3.9, 4.3 5.5, 6.5
cellulose
acetate
3 mil 2.2, 7.0 5.0, 5.7
cellulose
acetate
VI-6
-------
Fig. 1
. 5
VI-7
-------
Fig. 2
J->"*"'
.2 urn
. ฃ
^...
*...y .,:.i
......*"r
,r
.2pm
.2
VI-8
-------
22
23
24
25
26
27
Fig. 3. Adaxial surfaces of tomato (A, B) and pepper (C, D) leaves
from plants grown under a high UV light source with mylar (A, C)-
and 3 mil cellulose acetate (B, D) film filterslow
magnifications.
VI-9
-------
23
24
25
26
27
Fig. 4. Adaxial surfaces of tomato (A, B) and pepper (C, D) leaves
from plants grown under a high UV light source with mylar (A, C)
and 3 mil cellulose acetate (B, D) film filtershigh
magnifications.
VI-10
-------
8
9
10
12
13
14
15
16
17
16
19
20
21
22
23
24
25
26
27
Fig. 5. Wax fractions by chemical groups in the surface waxes of
tomato leaves from plants grown under a high UV light source with
4 mylar or 3 mil or 5 mil cellulose acetate film filters. Each
sample was spotted using 5 yl of a 10 mg total wax/g CHC13 (1%)
solution per spot and separated with Benzene:acetic acid (99:1)
tentative spot identification follows according to the numbers to
right of spots: 1acids, 2'-triterpenoids or fatty acids,
2fatty acids, 3fatty acids, 4--primary alcohols, 5unknown,
6ketone or aldehydes, 7--alkene or alkyl ester, 7paraffins.
11'
Fig. 6. Wax fractions by chemical groups in the surface waxes of pepper
leaves from plants grown under a high UV light source with mylar or
3 mil or 5 mil cellulose acetate film filters. Each sample was
spotted using 5 pi of a 10 mg total wax/g CHC1 (1%) solution per
spot and separated with benzene:acetic acid (99:1). Tentative spot
identification follows according to the numbers to right of spots:
1acids, 2fatty acids, 3fatty acids, Aprimary alcohols,
5unknown, 6ketones or aldehydes, 7paraffins,
VI-11
-------
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-------
EFFECTS OF ULTRAVIOLET-B RADIATION ENHANCEMENT
ON INDUCTION OF PHENYLALANINE AMMONIA LYASE AND
ETHYLENE PRODUCTION
Abstract
Only preliminary assays showed phenylalanine ammonia lyase activity to
increase with increase UV-B radiation. These results need corroboration.
Ethylene production showed a consistent decreasing trend with UV-B radiation,
apparently being inhibited by UV-B treatment.
VI I-1
-------
Introduction
Under inductive conditions the limiting factor in flavanoid synthesis
.may be the enzyme phenylalanine ammonia lyase which is responsible for the one
step deamination of phenylalanine to cinnamic acid, a precursor in flavanoid
biosynthesis. The present study was undertaken to determine if higher levels
of P.AL could be detected in tomato peel tissue after exposure to UV-B radiation.
'Walter'tomato plants of the same seed lot as was used in the Duke Univer-
sity Phytotron and in the field study were grown and tomatoes of the "mature
..green" stage (3-6cm) harvested for experimental purposes. Tomatoes were placed
in a pan with the stem and stylar axis parallel to the FS-40 sun lamps and
height on each tomato x^as adjusted so the upper surfaces of all tomatoes in
.a pan were even (Appendix 1-41). Also, the height of each pan was adjusted to
give 0, 4, 2, and 1 UV-Bseu in pans covered with Mylar, 3, 5 and 10 mil cellu-
lose acetate, respectively. The tomatoes were irradiated for 12 of 24 hours
for 3 days and then analysed for PAL activity.
Analytical Procedure
Internal Ethylene Concentration;
Eight tomatoes per treatment were used and an internal gas samples was
taken from each at the end of the UV-B radiation enhancement period prior to
the PAL analyses. Ethylene was determined in the gas samples by the use of a .
Hewlett-Packard M-400 gas chromatograph equipped with a hydrogen flame ioniza-
tion detector. Separation was accomplished on an activated alumina column at
60ฐC with N2 as the carrier gas. The system can be used to detect down to 10
ppb with a - 10 % error.
Phenylalanine Ammonia-Lyase Determinations:
A modified method of Rahe _e_t _al_. (1970) and Aoki et^ jil. (1971) was used
to extract PAL. Tomato peel tissue was cut into small pieces and blended with
VTI.-2
-------
cold ethyl ether (-20ฐC). The homogenate was filtered on a Buchner funnel by
suction and the residue washed several times with cold ethyl ether and dried
in a vacumm desiccator at 0ฐC. For the preparation of enzyme solution Ig of
ethyl ether powder was suspended in 40 ml of 0.05 M sodium borate buffer (pH8.8)
at approximately 3ฐC for 1 hr and the suspension cleared by centrifugation at
7000xg for 10 rain at 0ฐC. The supernatant was used as the crude enzyme pre-
paration.
PAL activity was assayed spectrophotometrically by measuring trans-cinnamic
acid formed according to the method of Koukol and Conn. The reaction mixture
consisted of 1 ml of 10"^M L-phenylalanine, with 2 ml of 0.05 M sodium borate
buffer (pH8.8) and 1 ml of enzyme solution. Distilled water was added to the
blank. The mixture was incubated for 3 hours at 30ฐC. The reaction was
stopped by adding 0.1 nil of 6N hydrochloric acid. The acidified mixture was
extracted once with 5 ml of peroxide-free ethyl ether, that was removed and
evaporated to dryness at room temperature under an air stream by a fan. The
residue was dissolved in 4 ml of 0.05 M sodium hydroxide and the optical den-
sity determined at 268 nm. Enzyme activity was expressed in mu moles of trans-
cinnamic acid formed per g of fresh weight of tissue per 3 hours under the
conditions described above.
In the initial assays, PAL activity appeared to be higher in tomatoes
receiving the higher UV-B enhancement levels, however, subsequent runs did
not corroborate the earlier assays.. This work is being repeated with some
modifications in procedure.
Concentrations of ethylene in the internal air spaces of the fruit imme-
diately after treatment demonstrated a decreasing pattern with increasing UV-B
radiation enhancement levels. This is consistent with the findings on bean
petioles (see section IX) where high doses of UV-B radiation (greater than 1.5
UVBgeu) inhibited ethylene production.
VII--H
-------
Literature Cited
1. Rahe, J.E., J. Kuc and C. Chuang. 1970. Cinnamic acid production as a
method of assay for phenylanine ammonia-lyase in acetone powders of Phaseo-
lus vulgaris. Phytochemistry 9: 1009-1015.
2. Aoki, S., C. Araki, K. Kaneko and 0. Katayama. 1971. Occurrence of L-
.phenylalanine ammonia-lyase activity in peach fruit during growth. Agr.
Biol. Chem. 35: 784-787.
VII-A
-------
Table 1. Ethylene production by UV-B treated tomatoes.
" seu
Enhancement
0
1.8
2.1
4.1
Ethylene
Cone. (ppm)
6.40
4. SO
2.80
0.76
1 Length of exposure was 36 hrs in a 72 hr period of 12
hrs radiation: 12 hrs dark.
2
Analyzed in a 1 ml of gas sample from the internal gases
of the fruit. EThylene measurement was performed with a
Hewlett:packard M-400 gas chromatograph equipped with a
H2 flame ionization detector and a 0.6 x .003 in. activated
alumina column.
VCi-o
-------
EFFECTS OF ULTRAVIOLET-B RADIATION ENHANCEMENT
ON CHLOROPHYLL a, b AND TOTAL OF AVOCADO LEAVES
Abstract
Short term decreases in total, a and b chlorophyll were observed after
8 minutes exposure to UV-B at 295nm, 3.36 joules. This was followed by
increases and then a leveling off in content consistent with dark degrada-
tion. Induction of flavanoids in the avocado leaf system was most effec-
tive at 295nm.
Introduction
Exposure of plants to UV-B radiation in controlled environment
chambers caused a significant decrease in chlorophyll content (see Section
V), particularly in certain areas of leaves. Photosynthesis has been
demonstrated to be affected by UV-B radiation (see references in section
V). The objective of these preliminary experiments was to study rapid
changes in chlorophyll - a prominent visual pigment system of higher plants.
that are the primary pigments of the photosynthetic apparatus of the cell.
An analysis of stability or non-stability, and if the latter, as related
to rates of changes and photon fluence,could indicate the destruction of
VIII-1
-------
chlorophyll, inhibition of synthesis or loss of functional position in the
photosynthetic apparatus. This work was -undertaken to describe quantitative
and qualitative changes in total as well as chlorophyll a, b and their
ratios after exposure to 7nm ban widths of UV-B radiation.
Materials and Methods
Mature, healthy avocado leaves are long-lived when detached from the
-.plant and kept in a high humidity chamber. Avocado leaves 15-20cm long
were exposed for various lengths of time to UV-B with a 7nm bandpass
centering on either 290, 295, 200, 305, 310 or 315nra. The tissue area
2
exposed at any one time was 1 cm . A xenon lamp (Appendix 1-40) served
as the UV-B irradiance source. There were 3 to 13 exposure replicates
made for each observation. After exposure the leaves were placed between
moistened paper toweling and kept in the dark for the designated length of
-incubation.
2
One cm leaf sections were ground in cold 80% acetone saturated with
magnesium carbonate. Each sample was centrifuged for 10 min, filtered and
'the pellet re-extracted. Combined extracts were made to a standard volume
and absorbance at 663 and 645nm were determined using a Beckman DB-G grating
spectrophotometer. Chlorophyll a, b and total x^ere calculated according
to Arnon (1949) as follows:
Total chlorophyll, mg/1 = 20.2 (OD.._) + 8.02 (OD^ .)
663
Chlorophyll a , mg/1 = 12.7 (OD,,_) - 2.69 (OD.._)
OD-5 DH-)
Chlorophyll b , mg/1 = 22.9 (OD,.,.) - 4.68 (OD,,-)
' obJ
VITI-2
-------
Results and Discussion
As can be seen from Table 1, there is an indication that irradiances
of 290 and 295nm lowered chlorophyll b content. Hox^ever, the data is' not
conclusive enough to obtain an action spectrum for a change in chlorophyll.
It does indicate that the shorter wavelengths are interacting with chloro-
phyll to lower content. That there is an after-effect on chlorophyll
quantities of avocado leaves after exposure to UV-B radiation can be seen
by the data of Fig. 1 and Table 2. Exposure of leaves to 8 minutes of UV-B
-2
irradiance of 3.36 Joules cm and then incubating the leaves in the dark
resulted in transient changes in both chlorophyll a and b. Both decrease
immediately after the UV-B treatment and then increase. This was followed
by another decrease with chlorophyll b affected the most. Dose vs rate
changes are still under study but at the present it does seem that. UV-B
radiation is having an immediate effect on chlorophyll metabolism.
Induction of flavenoids in this avocado leaf test system is also
being investigated. Appendix 1-40 shows that UV-B at 295nm is the most
effective wavelength. At least 2 or more days incubation time is required
for the pigments to be seen visually and this is dependent upon the length
and amount of exposure.
Literature Cited
Arnon, D.I. 1949. PI. Physiol., Lancaster 24: 1-15.
VIII-3
-------
Table 1. Chlorophyll content of avocado leaves exposed to 7nra bandpass
UV-B radiation for 8 and 16 minutes.
% of Control
Chi, a Chi, b Total Mean UV-B Joules
nra 8" 16" 8" 16" 8" 16" a/b ratio 8" 16"
290 105 92 106 59 197 165 2.74 1.92 3.84
295 102 100 116 87 202 203 2.38 3.36 6.72
300 102 96 101 97 198 198 2.31 4.80 9.60
305 92 110 75 76 202 151 3.21 5.76 11.52
310 100 112 100 103 212 203 2.55 5.76 11.52
315 101 108 101 103 209 204 2.35 4.32 8.64
VIII-4
-------
Figure 1. Chlorophyll content of avocado leaves
exposed to a 7 ran bandpass of UV-B at
_2
295nra giving 3.36 Joules cm " over an
eight minute exposure period.
VI T.I-5
-------
Fig. 1
I
ON
CHLOROPHYLL A
CHLOROPHYLL B
TOTAL CHLOROPHYLL
120
INCUBATION PERIOP
(Min.)
240
-------
2
Table 2. Chlorophyll content and a:b ratio of 1 cm avocado leaves
exposed to a 7 nm bandpass UV-B at 295nm giving 3.36 Joules
-2
cm over an 8 minute exposure period.
% of Control
LncuDau-Luu
Period(min)
0
8
16
24
32
60
90
120
150
180
240
Chi. a
102
98
95
99
106
95
93
88
90
93
93
Chi. b
106
91
89
93
119
97
88
80
87
84
92
Total Chi.
103
96
93
97
111
95
92
86
90
90
93
I'iKciri
a: b ratio
2.52
2.78
2.72
2.73
2.50
2.78
3.09
3.23
3.05
3.30
3.13
VITI-7
-------
EFFECT OF ULTRAVIOLET-B RADIATION ENHANCEMENT
ON ABSCISSION, ETHYLENE PRODUCTION, ABSCISIC
ACID AND SEVERAL ENZYMES'OF LEGUMES
Abstract
Intermediate levels of UV-B radiation (1 UV-Bseu) hastened the abscission
processes of bean explants but higher levels (2 and 4 UV-Bgeu) inhibited
abscission. However, intermediate levels of UV-B had no measurable effect on
ethylene production but the higher level (4.2 UV-B ) stimulated it. Bean
SGU
plants exposed to levels of 1.2 and 2.1 UV-B enhancements had greater
amounts of abscisic acid in the stem exudates, presumably xylem fluid.
RuDP-carboxylase in leaves was not altered by 1.2 and 2.6 UV-B levels of
J J seu
enhancement. Two cellulase isozymes were inhibited by UV-B radiation.
Introduction .
Abscission of plant organs plays a prominent role in survival of higher
plants to environemntal stress factors. Intimately associated with the
mechanism of positive shedding of organs are growth regulators (see references
in Kozlowski, ed. , 1973) such as abscisic acid (Cams, 1966) ethylene (see
references in Abeles, 1973) and auxin (Biggs and Leopold, 1958) and certain
enzymes. A prominent enzyme complex associated with the separation processes
IX-1
-------
.are cellulases (see references,Kossuth and Biggs, 1977). Other enzymes not
directly involved with separation but which are indicative of associated
sequencing of natural processes are.changes in pigments, proteins and other
nitrogen metabolic processes, translocation phenomena etc. (Addicott, 1968).
Since the abscission process is so closely related to stress factors, is a
correlative phenomena, is most prominent on organs exposed to light, and has
a biological endpoint that is not death of the entire organism, it was chosen
as a pivotal process for studying UV-B radiation on beans. Certain legumes
.which includes beans, are excellent test organisms for several reasons. They
'have evolved a complex system for autotropy of intermediate oxides and reduced
forms of nitrogen, yields of seeds are strongly related to photosynthesis,
.the cultivated plants in this family play a major role in supplying world
food demands and much information is available on the response of this family
.of plants to environmental stress factors.
Materials and Methods
Plant Material
Glycine max (L.) Merr. var. 'Hardee1 and Phaseolus vulgaris L. var.
'Tennessee flat1 beans were used as the test plants. Both test plants were
grown in the greenhouse using the same UV-B irradiators as discussed in
section I. The level of UV-B enhancement varied with different tests and
will be described with each. In the case of the beans, plants were some-
times decapitated or explants made of leaf parts to include abscission
zones. These will be described with the test systems. All plants were
grown in pots of Redi-earth, a commercial potting mix of peat and vermiculite
and grox^n without disease and with all other factors, except UV-B treat-
-------
merits, being as uniform as possible.
Bean Abscission Bioassay
The primary leaves of three-week-old seedlings of Phaseolus vulgaris
L. var. 'Tennessee flat1 were used as the source of the explant. The explant
was made to include 5mm of petiole and 5mm of the leaf pulvinus up to the
base of the leaf blade. Ten explants were inserted with the petiole por-
tion to a 3mm depth in 3% agar in small containers and each treatment had
3 containers of explants. The explants were kept at 25 C and examined.
every 24 hours for numbers that abscised the pulvinus tissue (Appendix 1-41).
Ethylene Analysis
y
Gas samples to be analyzed for ethylene were injected, 1 or 0.5 ml,
on the column for analysis. A Hewlett Packard M-400 gas chromatograph
equipped with a hydrogen flame ionization detector, a 0.5 x .003 M activated
alumina column, operated at an injection port oven temperature of 60 and
detector temperature of 215 and Nป flow of 60 ml/min. was used.
Abscisic Acid Analysis
Stem exudates from bean plants were separated using a DuPont model
860 high pressure liquid chromatography system equipped with a microporasil
column and a UV-detection system at 254nm. Abscisic acid has a strong
absorbance at the 254nm wavelength. Separation was on the microporasil
column using 15% (v/v) acetonitrile in chloroform acidified with 0.2 N
formic acid at a programmed linear flow rate of 2 ml/min. This system is
similar to the one used by Ciha, Brenner and Brun (1977).
IX-3
-------
A 'Hairy Peruvian1 alfalfa seed bioassay was used to test fractions
separated from the exudates for inhibitory action. The test consisted of
placing 50 seeds on 2.0cm filter paper discs moistened with water and
test substances in special flat bottom, small beakers and allowed to
germinate 24 hours (Biggs, 1971). Each test fraction was replicated 4 times.
RuDP-Carboxylase Assay
Approximately 500 mg of fresh leaf with midrib removed were ground in
a glass homogenizer with 10.0 ml of a solution that was 50.0 mM Tris (pH 8.0),
10.0 mM MgCl2, 1.0 mM EDTA, 5.0 mM D-isoascorbate, and 5.0 mM DTT. The ex-
tracts were centrifuged at 30,000 g for 15 min and then assayed immediately
for RuDP-carboxylase activity.
14
The activity of the enzyme was assayed by measuring the rate of C-
labeled C0? incorporation into acid-stable products. The reaction vessels
contained 1.0 ml of a solution that was 50.0 mM Tris at pH 8.0, lO.OmM
MgCl2, l.OmM EDTA, 5.0 mM DTT, 0.4mM ribulose-1,5 diP, and 20.0 mM NaH C03
(2.0 uCi). The reaction was initiated by addition of leaf extract and
14
terminated after 5 min by addition of 0.1 ml of 6. ON HC1. Gaseous CO,,
was removed from the reaction vessels by a stream of compressed air. The
radioactivity of the samples was determined by scintillation counting.
Chlorophyll content was determined by suspending 50ul of leaf extract in
20 ml of 80% acetone. The absorbance at 652nm (1cm light path) was determined
and then the value was m .Itiplied by a factor of 100/9 to approximate the
chlorophyll content of the suspension in ug/ul.
IX-4
-------
Cellulases
Cellulases were extracted from bean abscission zones using 0.2M
phosphate buffet:: 1M NaCl (pH-7) media. The tissue V7as ground in the ex-
traction media, centrifuged at 12,000 g to remove cellular debris, supernatant
decanted, filtered through an Ainicon molecular sieve to pass solution plus
solutes greater than 30,000 MW. The residue on the surface of the sieve
was resuspended in an ampholine plus gel matrix and applied to an agarose:
ampholine flat-bed gel for pH focusing for 16 hours at 8 watts. A model 2116
LKB Multiphor and 2103 power supply was used for the ionophoresis.
After separation the gels were subdivided into 30 equal sections, each
section was ground and eluted with buffer through special filter tubes supplied
by LKB, and the eluted fractions tested for cellulase activity by viscometric
analysis using carboxymethyl cellulose as the substrate.
Results and Discussion
Intermediate levels of UV-B radiation (1.2 UV-B ) accelerated the
seu
abscission processes of bean petioles but higher levels (2.6 and 4.2 UV-B )
inhibited the processes in relation to control explants (Table 1). The
promotion of abscission is in agreement with a previous report (Cams, et
al., 1975); but the inhibition .was not evident on cotton explants. This
could indicate that the bean petiole abscission zones are more responsive
to UV-B radiation. There was a marked difference in the response of cotton
and bean to UV-B with the beans being much more sensitive in the Phytotron
screening tests.
IX-5
-------
Table 1. Effect of UV-B radiation enhancement on the time required
for 50% abscission of bean explants.
2
Treatment
Cciintrol (Mylar)
1.2 UV-B
seu
2.6 UV-B
seu
4.2 UV-B
Hrs. to 50% Abscission
128
72
137
160
seu
Three-week-old beans were decapitated 1 cm above the primary leaf blade
and the decapitated plant exposed to UV-B (see Appendix 1-40). Subse-
quent to UV-B exposure, explants were made, of the petiole and pulvinus
to include the abscission zone (see Materials and Methods).
UV-B irradiance enhancement was for 6 hours for 3 days from 0900 to
1800 hours in the greenhouse.
IX-6
-------
Fig. 7
D.
O.
8 z
i o
^ f-
o:
UJ
O
d
o
UJ
f
111
70 -
60 -
50 _
40 _
30 _
20 _
10 _
SUNLIGHT CONTROL
D MYLAR CONTROL
O 5 MIL
-------
Ethylene .
Increases in doses of UV-B radiation beyond a threshold amount seemed
to stimulate ethylene production (Fig.l). The control explants were from beans
exposed to natural sunlight in the greenhouse. Ethylene production from
beans exposed to mylar filtered FS-40 irradiance plus sunlight and 5 mil
cellulose acetate filtered FS-40 lamp irradiance was approximately the same.
FS-40 lamp and 3 mil filter combinations, resulting in 2.6 UV-B enhancement
r SGu
stimulated ethylene production. The increase in ethylene production rein-
forces the concept that UV-B radiation hastens senescence of organs of some
plants.
Abscisic Acid
Abscisic acid in the exudates from stems were higher in beans exposed to
UV-B irradiances. As shown in Table 2, a 1.2 UV-B enhancement level re-
SGU
suited in a doubling of the concentration in the exudates and plants exposed
to 2.1 UV-B had 2.4 times as much abscisic increase as a result of ultra-
S GU
violet radiation stress. Abscisic acid may play a role in photoprotection of
the plants. The interesting feature of these tests is that UV-B must be
affecting the entire plant, including the root system, for presumably the
increase in abscisic acid is produced in the roots and is being transported
to the shoots in the xylem. Root bicmass was affected by UV-B in other
tests and part of this affect may be through chemical regulators.
IX-8 '
-------
Table2. Abscisic acid content of stem exudates from beans grown
2
under UV-B irradiance enhancement.
., % alfalfa seed
Treatment mgABA/Plant inhibition^
Control(Mylar) 190.1 94
1.2 UV-B 380.5 33
seu
2.1 UV-B 454.7 22
seu
Three week-old beans were decapitated at the cotyledonary node and
200ul of exudate collected from each of 40 plants.
2
Irradiance determined as outlined in section I.
3
Calculation based on high pressure liquid chromatography analysis.
4
Separated fraction from high pressure liquid chromatography and
tested in alfalfa seed bioassay.
IX-9
-------
RuDP-Carboxylase
We tested bean leaves for the possible -effect of UV-B radiation
on the primary carboxylating enzyme, RuDP-caroxylase. The data of Table
3 indicates that there was no reduction in the level of this enzymes under
these test conditions.
Cellulases
Bean seedlings 3-weeks from emergence were decapitated just above the
two primary leaves and exposed to 2 UV-B for 3 days for 6 hours per day
from 0900 to 1500 hours in the greenhouse(see Appendix 1-41 for an example
of the type of bean plant treated). After exposure, 50 bean explants 2mm
in length were cut from the pulvini:petiole area at the base of the primary
leaves. The abscission zone was at mid-point of the explant. All 50 ex-
plants were ground and cellulases extracted.
Molecular sieving and an LKB ionophoresis unit was used to investigate
the isozymes in the bean petioles. lonophoretograms of molecular sizes
greater than 30K in the pH range of 2.2 to 9.2 have shown that at least 6
different isozymes are present in non-treated abscission zone tissue
(Fig. 2). From the UV-B radiation treatment (2 UV-B ), cellulases
ScU
extracted from abscission zone tissue were in lesser amounts and fewer in
number than the controls. This is in agreement with the observations in
the previous section that a 2 UV-B level of enhancement inhibited abs-
ssu
cission even though ethylene production was stimulated.
IX-10
-------
Table 3. Ribulose-l,5-diphosphate carboxylase activity of
soybean leaves grovm under control (mylar), 1.1 and
2.3 UV-B enhancement regimes.
seu 6
RuDP-carboxylase activity
(umoles C00 mg"1 chl. h+1
Treatment
Control(Mylar) 24Q2
221
1.2 UV-B
2.6 UV-B 218
seu
Soybean leaves exposed to UV-B radiation for 14 days for 6 hours
per day from 0900 to 1500 hrs. in the greenhouse. UV-B en-
* J & seu
hancement determined as outlined in section I.
'Average of 4 'determinations. The means were not: significantly
different from each other at p = 0.05.
TX-11
-------
Fig. 2
6
5
h-
E 3
O o
85 I
0
a
BO B
B a
o
ป a
COMBINED BEANS
I Hr.
a B a
e-e o-e-e-ฎ-#-ฎ-ฎ-0-ฎ o-a-o-a-o-o o-o o-o-e-o-ซ
t i i i i i i i i i i i i i i i i i i i i i i i i i i i i i
7
6
5 pH
4 *
3
2
10 15 20
FRACTION NUMBER.
25
30
5
e
> 4
> 3
8 O -
a Q a
SUNLIGHT BEANS
I Hr.
eoฐ
a a
: T / /v\ .
I / M \ A
o-o o o-o
o o-o o o
I I I I I I I I I I I I I t I I I I I I I I I 1 I I I I I I
9
8
7
6
5 pH
4
3
2
10 15 20
FRACTION NUMBER
25
30
IX-12
-------
. Literature Cited
1. Abeles, F.B., 1973. Ethylene in Plant Biology. Academic Press.
New York.
2. Addicott, F.T., 1968. PI. Physiol. 43: 1471-1479
3. Biggs, R.H., and A.C. Leopold. 1958. Am. J. Bot. 45: 547-551.
4. Biggs, R.H. 1971. HortScience 6: 388-392.
5. Cams, H.R. 1966. Ann. Rev. PI. Physiol. 17: 295-314.
6. Cams, H.R. and M.N. Christiansen. 1975. C.I.A.P. Monograph
5. Chapter 4: 93-97.
7. Ciha, A.J., M.L. Brenner and W.A. Brun. 1977. PI. Physiol.
59: 821-826.
8. Kossuth, S.V. and R.H. Biggs. 1977. Proc. International Soc.
Citriculture III.
9. Kozlowski, I.E., (ed.) Shedding of Plant Parts. 1973. Academic
Press, New York.
IX-13
-------
EFFECTS OF ULTRAVIOLET-B RADIATION ENHANCEMENT
ON REPRODUCTION AND VEGETATIVE GROWTH OF BLUEBERRY
Abstract
Berry weight was reduced by 50% on fruits from plants grown
under 2 UV-Bseu and 1 UV-B enhancement levels. Mylar control
plants had more shoots and larger leaves than UV-B treated plants.
Introduction
The vegetative and reproductive capacity of blueberries (Vacciriium
ashei cv. 'Woodard') under UV-B enhancement regimes was studied. Ob-
servations on annual crops have shown that yields and vegetative biomass
may be reduced. No such studies have been conducted with perennial
crops, especially tree crops which are past juvenility stages.
Materials and Methods
Rooted cuttings of the cultivated blueberry variety 'Woodard'
which had been in cold storage since October were potted on May 10,1977
in Redi-Earth soil mix and allowed to grow under normal greenhouse
conditions until May 18 when the UV-B enhancement regimes were begun
X-l
-------
an the greenhouse (Appendix 1-1). Seven to 10 plants were placed under
Mylar, 3 mil, 5 mil and 10 mil cellulose acetate (CA) which was changed
every 3 or A days. The 3 mil CA filtered plants were set for 2 UV-Bgeu
and the other fixtures raised to the same distance from plant height as
the 3 mil plants. The blueberry plants were irradiated for 6 hours per
day in the center of the natural photoperiod for almost 4 months until
berry harvest. -
Initial data taken on the plants included number of vegetative and
inflorescence shoots and number of leaves per shoot. Each plant was
thinned to a maximum of 2 inflorescences and then to 2 well developed
flowers per inflorescence, which were hand pollinated at anthesis. On
-September 9, 1977 each plant and all fruit were harvested. Data was taken
on the number of fruits, weight of fruit, number of shoots, number of
ileaves per shoot and leaf area per plant.
Results and Discussion
Blueberries from the control plants had larger berries and higher
;percentages of berries matured than 1 and 2 UV-Bseu treated plants. The
^blueberry from the 10 mil treatments weighed the same as the mean of the
5 control blueberries. These blueberries were twice as heavy as the 1 and
;2 UV-B^,, treated berries (Table 1).
oC-U
Large differences were also observed in vegetative grox^th with the
control plants showing an increase in the number of shoots per plant from
0.9 to 8.3 vs 1.57 to 5.71 for the 1 UV-B treated blueberries (Table 1).
SฃU
-However, the number of leaves per plant was lower on the control than on
.the UV-B treated plants. Leaf area on a per leaf basis was about the same
X-2
-------
Table 1. Vegetative and reproductive development of rooted'Woodard'
blueberry cuttings exposed to UV-B enhancement.
Parameter1 2UV-Bฃ,,M1 1UV-B 0.5UV-B Mylar
seu seu seu Control
1. # plants 77 78
2. // flowers pollinated 2.29 2.00 2.00 1.80
3. absolute berry # 3.00 4.00 1.00 5.00
4. # berries matures 0.43 0.57 0.25 0.50
5. % berries matured 0.19 0.28 0.13 0.29
6. berry weight (g) 0.54 0.43 0.99 0.99
7. f shoots (May) 1.29 1.57 1.25 0.90
8. // shoots (Sept.) 5.00 5.71 5.29 8.30
9. # leaves (May) 9.14 8.14 9.88 6.80
10. //leaves (Sept.) 48.43 57.29 58.14 49.80
11. leaf area,cm2(Sept.) 249 290 303 278
12. leaf area/leaf 5.13 5.06 5.20 5.59
(Sept.) cm2
Parameters are expressed as mean values per plant for the
designated UV-Bseu treatment.
X-3
-------
f\
for all levels of UV-B enhancement ranging from 5.06 to 5.2 cm . The
control was slightly higher with 5.59 cm2 (Table 1).
It was apparent that vegetative growth on the control plants was
different from treated in that controls had more shoots but fewer leaves
that were larger whereas the UV-B treated plants had a larger number of
smaller leaves on fewer shoots. The expected reduction in individual
leaf area often observed under enhanced UV-B treatment was observed but
the larger number of shoots on the control plants was not. The limited
sample size and variation in cutting size, establishment and initial out-
growth after removal from the long cold storage period may account for
some of the variability.
X-4
-------
EFFECTS OF ULTRAVIOLET-B RADIATION ENHANCEMENT
ON REPRODUCTION AND VEGETATIVE GROWTH OF CITRUS
Citrus irradiators were constructed in the field (Appendix 1-1) in
March, 1977 and placed .7 meters from 'Washington' navel trees in full
bloom. A .7 m x 1.3 m area was flagged on each tree for the center of
the UV-B treatment. Each flowering shoot was tagged, number of flowers
determined, type of inflorescence scored and flowers pollinated. The
same area was marked, flowers pollinated and data taken on control trees.
The FS-40 lamps were filtered with 5 mil cellulose acetate which was changed
twice weekly. Irradiation was for 6 hours per day in the center of the
photoperiod.
'Washington' navel orange trees were very resistant to damage from
UV-B radiation. There were no apparent differences, between vegetative or
reproductive growth on UV-B treated area and non-treated areas. However,
in the fall and winter under increasing water and cold stress, premature
leaf abscission was observed to occur. This observation will be used to
test interactions of stress on abscission per se and on cold tolerance.
XI-1
-------
EXPERIMENTATION UNDERWAY
UV-B Radiation Activation of Plant Viruses
During the screening trials it was noted that the symptoms at
intermediate levels of UV-B irradiance (2UV-B ) on several species
SGU.
in the Solanaceae and Leguminosae families resembled those observed on
viral infected plants. Since seed-borne viruses are prevalent in these
two families and cause many production problems in agriculture, a test
was made for potato yellow virus on controls and UV-B treated plants of
bell pepper, tomato, soybeans and beans. The virus was present in
detectable quantities on a few plants in each treatment of bell pepper
and beans to indicate some plants were infected. The titer of the virus
was slightly higher in the pepper and bean in the 2 UV-B treatment
than in the control (mylar) and 4 UV-B treatment. The number of
J seu
plants infected was also greater for this treatment. On the basis of
these observations, tests are underway to determine whether UV-B radiation
could be activating latent viruses. The present investigations are underway
on bell pepper, soybeans, bean, yellow lupine and citrus. The tests are
of two types: 1) obtain seedlings from seed contaminated with the virus,
and expose them to various UV-B radiation enhancement levels from emergence
until testing for the presence of the virus in the seedling and the titer
XII-1
-------
of the viruses. 2) itmoculate the plants with viruses and determine, the
rate of increase in the titer with and without exposure to UV-B radiation
at different dose levels.
Effects of [P/-B Radiation on. Reproduction and Vegetative
Development of Several Fruit Crops
Containerized flowering plants of peach, blueberry, citrus and apple
are being tested in the greenhouse and field for possible effects of UV-B
radiation on pollination, fertilization, and fruit-set. These tests
were initiated as indicated under the grant and preliminary data are reported
for blueberries and citrus. It still must be recognized that with perennial
crops, long term studies must be made to be meaningful and these will
require ongoing programs.
XII-2
-------
UV-B BIOLOGICAL AD CLIiWE EFECTS RESEARCH
TERRESTRIAL FY 77
IMPACT OF SOLAR bV-B RADIATION On CROP PRODUCTIVITY
FEBRUARY 23, 1978 APPENDIX I FINAL REPORT
BY
R.H. BIGGS, PRINCIPAL INVESTIGATOR AND
S,V, KDSSUIH, PROJECT DIRECTOR
PREPARED FOR
UNITED STATES DEPT, AGRICULTURE/BNVIRONfeiTAi. PROTECTION AGENCY
[NGTOND.C, 20/160
-------
Appendix I Color Photographs
1. Color indicators on the photographs emphasize the following:
red = stunting, dwarfism
yellow = chlorosis, tip burn
blue = lateral bud breaking
green = cupping of leaves (concave or convex)
orange = reduction in vineness (twining)
white = red pigments
2. UV-B enhancement: Mylar = control, no UV-B radiation.
UV-Bseu: 0.5, 1.0, 1.5 and 2.0.
For soybean: 1 = 0.5, 2 = 1.0, 3 = 1.5, and 4 = 2.0 UV-B seu.
3. Pages 1-4: Field and greenhouse experiments.
4. Pages 5-22: Duke University Phytotron growth chamber screening
study, 82 species, 5 UV-B enhancement regimes.
Page 5: Growth chamber with experiment in progress.
Page 6-11: Chenopodiaceae, Cruciferae, Compositae
Page 12-13: Cucurbitaceae
Page 14-16: Leguminosae
Page 17-18: Gramineae
Page 19-20: Pinaceae
' ! ....
Page 21 ': Solanaceae, Liliaceae ; . .
Page 22 : Malvaceae, Leguminosae, Compositae - favored
and resistant species.
5. Duke University Phytotron "C" environmental chamber variety testing:
l
Page 23-26: Individual soybean varieties from each of the 5 UV-B
enhancement regimes,,
XIII-1
-------
Page 27-31: Comparison of several soybeans from separate UV-B
enhancement regimes and symptomology.
Page 32-33: Watermelon varieties.
6. Page 34: Field grown soybeans (Gainesville, Fl.) which may be UV stressed
(1977).
7. Page 35-37: Duke University Phytotfon greenhouse grown soybean leaves
and set-up for the factorial UV-B/PAR study.
8. Page 38-39: Comparison of soybeans and wheat by PAR and UV-B level.
9. Page 40: Xenon lamp irradiator and avocado leaf exposed to different UV-B
wavelengths for different times. Note pigmentation development.
10. Page 41: Tenn. Flat beans and tomatoes irradiated under laboratory condi-
tions.
XIH-2
-------
Appendix I Description of Color Photographs
Pictures are identified by position as top (T), middle (M), bottom (B), right
(R) or left (L).
Page No.
1. Greenhouse and field irradiators: (TL) FS-40 sun lamps and filter
arrangement in greenhouse; (TR) overview of UV-B field irradiator;
(ML) citrus tree irradiator; (MR) via-flow watering system for field
irradiator; (BL) radishes in the field irradiator; (BR) overview of
of UV-B field irradiator.
2. UV-B field irradiator for 1977 crops: (TL) potatoes in bloom; (TR)
silverqueen corn at maturity showing reduction in height; (BL) Walter
tomatoes; (BR) Southern peas.
3. UV-B field irradiator for 1977 crops: (TL) Florunner peanuts; (TR)
Star Bonnet rice; (BL) Florunner peanuts in bloom; (BR) yellow neck
squash.
4. UV-B field irradiator for 1977 crops: (TL) marginal chlorosis on
' mustard; (TR) mustard; (BL) Star Bonnet rice; (BR) environmental
measurement station adjacent to field irradiator.
5. Plants inside the Duke University Phytotron environmental "C" chamber.
Note FS-40 sun lamps, filter arrangement and reflective walls. See
. .table 1 for list of species in Phytotron screening study including the
O
number of weeks each was grown before harvest and pictures were taken. ฐ
r
6. Phytotron screening study, 1977: (TL) artichoke; (TR) broccoli;
(ML) brussel sprouts; (MR) cabbage; (BL) cauliflower; (BR) cauliflower.
7. Phytotron screening study, 1977: (TL) chard; (TR) collards; (ML)
chard; (MR) collards; (B) chard.
i
XIII-3
-------
8. Phytotron screening study, 1977: (TL) kale; (TR) kale; (ML) kohlrabi;
(MR) kohlrabi; (BL) kohlrabi; (BR) lettuce.
9. Phytotron screening study, 1977: (TL) mustard; (TR) rubarb; (ML)
mustard; (MR) rutabega; (B) rutabega.
10. Phytotron screening study, 1977: (T) radish; (M) mylar radish;
(B) x 2.0 UV-B geu radish with cupped and chlorotic leaves.
11. Phytotron screening study, 1977 showing cupping and marginal chlorosis
of Cruciferae seedlings: (TL) radish; (TR) brussel sprouts; (ML) kohl-
rabi; (MR) kale; (B) cabbage.
12. Phytotron screening study, 1977: (TL) cucumber; (TR) Hales best jumbo
cantelope; (ML) honeydew melon; (MR) watermelon; (B) pumpkin.
13. Phytotron screening study, 1977: (TL) acorn squash; (TR) early summer
squash; (BL) prolific squash; (BR) zucchini squash.
14. Phytotron screening study, 1977: (TL) garden bean; (TR) Jackson
wonder lima bean; (ML) pinto beans; (MR) Tenn. Flat bean; (BL) White
Dixie butterpea; (BR) White Dixie butterpea.
15. Phytotron screening study, 1977: (TL) Blackeye No. 5 cowpeas; (TR)
blackeye peas; (BL) Jackson wonder lima bean; (BR) little marvel
English peas.
16. Phytotron screening study, 1977: Hardd soybean: (TL) 4 UV-BSGU
levels; (TR) x 2.0 UV-Bseu; (ML) release from apical dominance;
(MR) bronzing; (BL) chlorosis; (BR) bronzing.
17. Phytotron screening study, 1977: (TL) Arivat barley; (TR) Silver-
queen corn; (ML) chufas; (MR) oats; (BL) Lebonnet rice; (BR) brown
top millet.
18. Phytotron screening study, 1977: (T) sorghum; (M) Jori wheat;
(B) Crane wheat.
XIII-4
-------
19. Phytotron screening study, 1977: (TL) loblolly pine; (TR) lodgepole pine;
(BL) ponderosa pine; (BR) slash pine.
20. Phytotron screening study; 1977: (TL) noble fir; (TR) white fir; (BL) noble
.fir; (BR) Douglas-fir.
21. Phytotron screening study, 1977: (TL) bell pepper; (TR) eggplant;
(BL) Walter tomato; (BR) onions.
22. Phytotron screening study, 1977: (TL) cotton; (TR) okra; (BL) Florunner
peanut; (BR) sunflower.
23. Phytotron soybean variety testing, 1977: (TL) x 2.0 UV-Bseu "G" environ-
mental chamber; (TR) Mylar control chamber; (ML) Acadian (MR) Altona,
showing release from apical dominance; (B) Altona.
24. Phytotron soybean variety testing, 1977: (TL) Americana; (TR) Biloxi;
(ML) Bossier; (MR) Centennial; (BL) Cobb; (R) Davis.
25. Phytotron soybean variety testing, 1977. (TL) Forrest; (TR) Hardee;
(ML) Hood; (MR) Button; (BL) Jupiter; (BR) Mineira.
26. Phytotron soybean variety testing, 1977: (TL) Otootan; (TR) Roanoke;
(M) Santa Maria; (B) Seminole.
27. Phytotron soybean variety testing, 1977, comparison among Acadian,
Americana, Altona, Biloxi, Bossier, Centennial varieties (T) Mylar;
(M) x 2.0 UV-Bseu (B) x 1.0 UV-Bseu.
28. Phytotron soybean variety testing, 1977, comparison among Cobb, Davis,
Forrest, Hood, Hutton, and Jupiter varieties: (TL) Mylar; (TR) x 0.5
UV-Bgeu; (ML) x 1.0 UV-Bseu; (MR) x 1.5 UV-Bseu; (B) x 2.0 UV-Bseu.
29. Phytotron soybean variety testing, 1977, comparison among Mineira, Hardee,
and Santa Maria varieties: (TL) Mylar; (TR) x 0.5 UV-Bseu; (ML) x 1.0
UV-BC(31]; (MR) x 1.5 UV-BCOI1; (B) x 2.0 UV-BC
XIII-5
-------
30. Phytotron soybean variety testing, 1977, comparison among Mineira, Otootan,
Pickett, Roanoke and Seminole varieties: (TL) Mylar; (ML) x 1.0 UV-Bgeu;
(MR) x 1.5 UV-Bseu; (B) x 2.0 UV-Bseu.
31. Phytotron soybean variety testing, 1977: Individual plant pictures show-
ing reduction in leaf area, chlorosis and leaf cupping.
.32. Phytotron Charleston Gray watermelon variety testing, 1977, comparison
among Charleston Gray control, Charleston Gray Fl. 77-1 and 77-2:
(T) Mylar; (M) x 1.0 UV-Bseu; (B) x 2.0 UV-Bgeu.
. 33. Phytotron Charleston Gray watermelon variety testing, 1977: (TL) Mylar;
(TR) Fl. 77-1; (BL) 77-2; (BR) Charleston Gray control.
34. Field grown soybeans at the University of Florida, Gainesville, Fl. show-
ing symptoms similar to UV-B affected plants grown under greenhouse and
Phytotron conditions.
35. PAR X UV-B study: (TL, TR) Phytotron greenhouse set-up with different
shading and UV-B levels; (ML) leaf, 100% sun, mylar; (MR) leaf, 100% sun,
0.5 UV-Bgeu; (BL) leaf, 100% sun, 1.0 UV-Bgeu; (BR) leaf, 100% sun, 2.0
36. PAR X UV-B study: (TL) leaf, 67% sun, 0.5 UV-Bgeu; (TR) leaf 67% sun,
1.0 UV-Bseu; (ML) leaf, 67% sun, 2.0 UV-Bseu; (MR) leaf, 45% sun, 0.5
UV-Bseu; (B) leaf, 45% sun, 1 UV-Bseu.
37. PAR X UV-B study: (T) Phytotron greenhouse set-up; (M) leaf, 12% sun,
1.0 UV-BSงU; .-(B) leaf, 12% sun, 2.0 UV-Bseu. . .-, . . .'
38. PAR x UV-B study: Comparison whole plant response of Hardee soybean under
mylar, 0.5, 1.0 and 2.0 UV-Bgeu. (TL) 100% sun; (TR) 67% sun; (BL) 45%
sun; (BR) 12% sun.
.39. PAR X UV-B study: Comparison whole plant response of Jori wheat under
!
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sun; (BR) 12% sun.
XIII-6
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40. (T) Pigment development in avocado leaf after various time exposures to
7nm bandwidth UV-B radiation supplied by (B) xenon lamp source.
41. Tennessee flat bean and tomato irradiated in the laboratory under FS-40
lamps: (T) whole plant abscission study; (ML) bronzing on bean leaf;
(MR) Laboratory set-up for irradiating beans and tomatoes; (B) irradia-
tion of tomatoes in the lab for PAL study.
' XIII-7
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FINAL REPORT
ULTRAVIOLET EFFECTS OF PHYSIOLOGICAL
ACTIVITIES OF BLUD-GREEN ALGAE
J. W. Newton
D. D. Tyler
M. E. Slodki
Northern Regional Research Center
Agricultural Research
Science and Education Administration
U.S. Department of Agriculture
Peoria, Illinois 61604
EPA-IAG-D6-0168
Project Officer:
R. J. McCracken
Agricultural Research, Science and Education Administration
U.S. Department of Agriculture
Washington, D.C. 20250
Prepared for
Environmental Protection Agency
BACER Program
Washington, D.C. 20460
-------
Introduction
The blue-green algae (Cyanobacteria] are found widespread in
nature, in soil, water, and in association with a variety of plant and
marine life C2). Various species can tolerate a variety of climatic
conditions and are found even in hot springs and arctic regions. These
cells lack differentiated chloroplasts and contain chlorophyll in
membranous structures; consequently, they have recently been classified
as blue-green bacteria, analogous to photosynthetic bacteria. The
cyanobacteria carry out a typical plant-type photosynthesis, however,
with water photolysis and oxygen evolution as major features. Consequently,
these ubiquitous organisms constitute a particularly useful microbial
system for monitoring worldwide environmental effects on plants as might
result from enhanced solar UV-B (280-320 nm) irradiation due to depletion
of stratospheric ozone (10).
We have evaluated both Anabaena flos-aquae and the water fern
Azolla as laboratory test systems for environmental studies. Azolla is
an aquatic nitrogen-fixing plant which contains a symbiotic cyanobacterium,
Anabaena, within its leaf cavity (4). This fern is also found worldwide,
.but is particularly important for its use as a green manure in rice
paddies in the Orient. Many species of cyanobacteria fix atmospheric
nitrogen and contribute to nitrogen input into soils in a variety of
ways. Both systems appear to be particularly important contributors of
nitrogen to rice culture.
2
-------
Our studies show that the nitrogen-fixing enzyme system in cyanobacteria
is particularly sensitive to UV-B damage. Furthermore, inhibition of
nitrogenase activity (measured as acetylene reduction) takes place in
the absence of any nucleic acid damage or lethal effects on the cells.
These studies indicate, therefore, that measurement of acetylene reduction
activity in nitrogen-fixing systems may provide a simple biochemical
assay for assessing the effects of UV-B on plants.
Materials and Methods
Azolla caroliniana, a nitrogen-fixing water fern, was obtained from
Dr. S. A. Peters, C. F. Kettering Foundation Laboratories, Yellow
Springs, Ohio, and was grown on modified Hoaglands salts as described by
Peters and Mayne (6). Anabaena flos-aquae (Lyngle.) Breb. ATCC 22664
was grown on nitrogen-free BG-11 medium (8). Cultures of plants and
. cyanobacteria were grown at 25ฐC in light chambers under cool white
fluorescent lamps at light intensity of 10-20 watts/I^. Measurements of
total light intensity were made with a Yellow Springs Instrument Co.
(Yellow Springs, Ohio) model 65A Radiometer equipped with a 6551 Radiometer
probe having a constant wavelength response from 0.28 to 2.6 microns
(reduced to 651 at 0.21 microns).
UV-B irradiation of samples was obtained using a bank of six 8-watt
RPR 3000 A Rayonet photochemical reactor lamps (Southern New England
Ultraviolet Co., 954 Newfield St., Middletown, Conn.) placed above
cyanobacterial and plant material at 25ฐC in flat dishes covered with
5 mil cellulose acetate films. The unfiltered RPR 3000A lamp has, in
addition to UV-B, a strong emission in the short wavelength region
(Amax ^254 nm). Such lamps were used either singly or in multiples to
increase irradiation.
3
-------
(We are grateful to Drs. K. Eskins and H. J. Button of this Center
for suggesting the use of these lamps as' a source of UV-B radiation.)
The lamps were aged 100 hours and did not significantly decrease in
irradiance levels during prolonged use thereafter. As recommended by
the Agricultural Equipment Laboratory of the Beltsville Agricultural
Research Center CBARC), 5 or 10 mil cellulose acetate (CA) film was used
to filter out low wavelength UV radiation from the lamps (5). The CA
was pre-irradiated 6 hours and discarded after 30-40 hours of use.
Since we have no knowledge of the actual targets involved, other than to
exclude DMA, our data are reported as total incident UV-B light over the
range indicated and does not assume any biological effectiveness of a
particular wavelength.
2 '''''
UV-B irradiance levels in W/m were measured with an Optronics
.Laboratories, Inc. Model 725 UV-B Radiometer (7). We calibrated this
instrument against a Rayonet lamp which had been scanned at distances of
13 and 20 cm (5 mil CA filter) with the Instrument Research Laboratory,
2
BARC, spectroradiometer over the 250-400 nm region. Integrated W/m
over the range of 280-320 nm at these distances were taken as reference
2
points CO.44 and 0.82 W/m , respectively) and linearly extrapolated to
provide estimates of higher UV-B irradiances.
Cyanobacterial suspensions of 40 ml were stirred during irradiation.
Aliquots were removed, rapidly agitated to separate clumped cells,
plated on BG-11 (N free) medium, and assayed for nitrogenase, fixation
of C 02 and hydrogen evolution. The data reported are typical examples
selected from many experiments which all gave consistent results.
4
-------
Acetylene reduction and hydrogen evolution were measured gas
chromatographically on cyanobacterial and fern preparations incubated in
light in screw-capped vials containing argon-acetylene or argon atmospheres.
Samples of the gas phase were periodically withdrawn with gas-sampling
syringes. Hie ethylene formed from acetylene was separated on columns
of Boropak R (9) and hydrogen measured using a molecular sieve 5A column
CD-
14
C Oj fixation was measured on aliquots of either A. flos-aquae or
14
fern fronds in growth media containing ^HC 0^. Samples were collected
14
on glass fiber papers, rinsed with 6N HC1, and the incorporated C
determined in a liquid scintillation counter using a water-miscible
scintillation fluid.
Concentrations of A. flos-aquae in irradiated suspensions, determined
by measurement of optical densities at 650 nm, were correlated with
protein content (3). With our cultures, an optical density of 1.0 at
650 nm corresponded to approximately 200 ygrams algal protein per milliliter.
Results
Because of their extensive pigment system, cyanobacteria are known
to be fairly resistant to short wavelength UV irradiation and to possess
an active photoreactivation system (11). In our early studies, we
confirmed both of these effects and determined killing curves for our
strains using an unfiltered Rayonet UV lamp (Figure 1). Comparison of
Fig. 1
-------
killing curves obtained by plating cell aliquots on plates which were
immediately incubated in the light with those allowed to incubate in the
dark 24 hours before illumination showed an active photoreactivation of
UV killing.
Figure 2 shows that when CA is used as a filter to remove short
Fig. 2
wavelength UV, the killing effect is virtually eliminated, even though
the measured UV-B radiation intensity has now been increased fivefold to
approximately 2.1 W/m . Note also that although the time scale has
changed from minutes to hours of irradiation, no lethal effect can be
observed.
We attempted to increase the UV-B irradiation by using a curved
bank of six lamps with a reflector to impinge the light more directly on
the reaction vessel. Figure 3 illustrates the results of such an
Fig. 3
experiment in which the UV-B intensity has been approximately doubled to
2
5.2 W/m . These data indicate some killing; however, there was only a
slow decline in the population of viable cells which suggests that only
a fraction of the cells may be sensitive to high intensity UV-B. It
would be of interest to use this approach as a means of selecting strains
with either enhanced resistance or sensitivity to UV-B.
-------
Two biosynthetic activities of A. flos-aquae were examined after
exposure to sub-lethal doses of UV-B: fixation of C (L and nitrogen
fixation (measured by acetylene reduction and hydrogen evolution).
Table 1 lists the effects of total UV irradiation and UV-B on acetylene
Table 1
reduction by Anabaena and indicates a decline in activity of algae
irradiated with UV-B in the absence of a lethal effect. For physiological
studies, concentrations of suspensions of A. flos-aquae were increased
tenfold. Plate counts of these suspensions indicated that, over the
range of 6-80 yg protein/ml, identical survival curves were obtained
allowing direct comparison of the results of viable cell count and
physiological activity of the suspensions.
Data in Table 2 show that, under similar conditions of irradiation,
Table 2
effects of UV-B on CC^ fixation were slight. From these results, it
appears that the nitrogenase system is a more specific and sensitive
target for UV-B damage in A. flos-aquae.
Experiments were performed to gain some insight into the nature of
the nitrogenase inhibition by UV-B. Since nitrogenase is a multienzyme
complex which can be assayed for in a variety of ways, we have also
measured the effect of UV-B on the ability of the complex to photoevolve
7
-------
molecular hydrogen. As can be seen in Table 3, the effect of UV-B on
Table 3
nitrogenase is negligible when this assay is used. Apparently, the
activity of nitrogenase measured specifically by the acetylene reduction
assay is the most sensitive indicator of UV-B damage.
of
Visible photobleaching/suspensions occurred after 6 hours irradiation
with UV-B. However, no destruction of a specific pigment could be
detected by examination of difference spectra of acetone extracts from
irradiated and unirradiated cells.
Discussion
From a practical standpoint, it is obvious that assessment of the
environmental effects of enhanced UV-B irradiation on biological material
is going to require development of simple assay procedures with wide
applicability. Our studies have consistently revealed a surprising
sensitivity of the nitrogenase complex to UV-B irradiation. The UV-B
2
irradiation level (ca. 3 W/m ), which we find inhibitory to nitrogenase,
is approximately the same as that of noon sunlight in the 280-330 nm
region. The main drawback to this approach to this means of assessment
of environmental damage is that it requires the use of those limited
systems which possess nitrogenase activity.
It should be emphasized that, by performing direct microbiological
plate counts on a large population of irradiated cells, we have ruled
out the possibility that the UV-B effect observed on nitrogenase is due
to nucleic acid damage. This finding suggests that the cellular target
8
-------
may be another pigment associated with the nitrogenase complex or its
electron transport system. Further studies on the action spectrum of
this effect may help to reveal the cellular component involved as UV-B
receptor.
The Azolla system provides an opportunity to examine the effect of
UV-B on a plant and, simultaneously, its symbiont. Since nitrogenase
activity (acetylene reduction) is exclusively a property of the symbiont,
this specific physiological activity can be measured after irradiation
14
of the fern. Measurement of fixation of C CU by the symbiosis serves
as a general index of the physiological activity of the system. Data in
14
Table 4 summarize such an experiment, in which C 02 fixation and
Table 4
acetylene reduction are measured in UV-B-irradiated plants. Although
there was a slow decline in general physiological activity of the plants
as the culture aged, the nitrogenase activity of irradiated plants
showed a significant decrease over control plants.
Information now available (12) on the effects of short wavelength
UV irradiation on biological material has come virtually exclusively
from studies of microorganisms. It seems likely, therefore, that
microorganisms may again prove to be the material of choice to study
biological UV-B effects. Nitrogen fixation consumes a substantial
fraction of the energy of a cell in which it occurs; consequently, it is
possible that a minor physiological disturbance would be expressed more
readily in such a system. Furthermore, this assay (acetylene reduction)
is readily adaptable to field studies and could serve as a convenient
assay for a variety of environmental studies.
9
-------
There seems little doubt that the green and blue-green algae will
be organism of choice to study large populations of plant material under
controlled conditions. Furthermore, since algal nitrogen fixation is
confined to blue-green algae (cyanobacteria), we seem to have selected
an ideal class of microorganism for evaluation of UV-B effects on plant
material. Worldwide distribution of these organisms suggests that they
might, in this way, serve as a convenient indicator of the extent of
stratospheric ozone depletion.
Abstract
The effect of UV-B (280-320 nm) irradiation on physiological
activities of Anabaena flos-aquae and the water fern Azolla caroliniana
has been studied where lethal effects of irradiation are known to be
absent. Nitrogenase activity specifically declined at low levels of UV-
B, under conditions which had little effect on general physiological
activity of the irradiated cells. These findings indicate that measurement
of acetylene reduction (nitrogenase assay) may serve as a simple biochemical
assay to assess environmental UV-B damage to plants due to depletions of
stratospheric ozone.
10
-------
References
1. Benemann, J. R., Berenson, J. A., Kaplan, N. 0., and Kamen, M. D.
1973. Hydrogen Evolution by a Chloroplast-Ferredoxin-Hydrogenase
System. Proc. Natl. Acad. Sci. U.S. 70_, 2317-2320.
2. Fogg, G. E., Stewart, W. D. P., Fay, P., and Walsby, A. E. 1973.
The Blue Green Algae, Academic Press, New York and London.
3. Layne, E. 1957. Spectrophotometric and Turbidimetric Methods for
Measuring Proteins, In Methods in Enzymology, S. Colowick and N. 0.
Kaplan (eds.), Academic Press, New York 3^ 447-454.
4. Moore,. A. W. 1969. Azolla: Biology and Agronomic Significance.
Bot. Rev. _35_, 17-34.
5. Rowan, J. D., and Norris, K. H. Instrumentation for Measuring
Irradiance in the UV-B Region. U.S. Environmental Protection
Agency. Annual Report, 1977, Interagency Program on Biological and
Climatic Effects Research, Washington, D.C.
6. Peters, G. A., and Mayne, B. C. 1974. The Azolla, Anabaena Azollae
Relationship. I. Initial Characterization of the Association.
Plant Physiol. ฃ3, 813-819.
7. Norris, K. H., and Rowan, J. D. Instrumentation for Measuring
Irradiance in the UV-B Region. Rev. Sci. Instrum. In preparation,
1978.
8. Stanier, R. Y., Kunisawa, R., Mandel, M., and Cohen-Bazire, G.
1971. Purification and Properties of Unicellular Blue-Green Algae
(Order Chroococcalesl. Bact. Rev. 35_, 171-205.
11
-------
9. Stewart, W. D. P., Fitzgerald, G. P., and Burris, R. H. 1967. In
Situ Studies on N2 Fixation Using the Acetylene Reduction Technique.
Proc. Natl. Acad. Aci. U.S. 58_, 2071-2078.
10. U.S. Congress. Senate Committee on Aeronautical and Space Sciences
Subcommittee on the Upper Atmosphere. 1975. Stratospheric Ozone
Depletion: Hearings Part 1 ง 2, 1-1060. Washington, B.C., Government
Printing Office.
11. Van Baalen, C., and O'Donnell. R. 1972. Action Spectra for
Ultraviolet Killing and Photoreactivation in the Blue Green Alga
Agmenellum quadruplicatum. Photochem. Photobiol. 15, 269-274.
12. Witken, E. M. 1976. Ultraviolet Mutagenesis and Inducible ENA
Repair in Escherichia coli. Bact. Rev. 4ฃ, 869-907.
12
-------
Table 1.
Effect of UV-B on nitrogenase activity
of A. flos-aquae
Irradiation
timea
h
0
0.5
1
2
3
6
Acetylene reduction
Control UV-B
nmol/h/rag protein
1,490 1,490
1,300 840
1,350 340
UV0
945
370
105
10
aUV-B, 2.1 W/m , cell suspension, 40 ml; protein
65 yg/ml.
Aliquots, 5 ml of suspensions incubated in light
in atmosphere of argon- 90%, acetylene 10% for
assay.
lamps without cellulose acetate filter,
2
10 W/m separate experiment, 40 ng/ml algal protein.
13
-------
Table 2
Effect of UV-B on fijcation of 14C07 by
6
A. flos-aquaea
Irradiation
Q
timea
h
0
2
4
6
14C02 fixed
Control
UV-B
cpm/mg protein/min
9,300
9,800
9,200
7,800
9,200
7,400
5,700
5,500
>>
UVD
in light
8,800
70
aCell suspension, 37 ml; protein, 50 yg/ml.
UV-B, 2.1 W/m2.
Tlayonet lamps without cellulose acetate filter,
10 W/m2.
14
-------
Table 3"
Effect of UV-B on photoevolution of H^ by
A. flos-aquae
Irradiation
timea
h
0
3
6
H2 evolution
Control
nmol/h/nig
460
350
265
UV-B
protein
460
343
215
aCell suspensions, 40 ml, 80 yg protein/ml,
exposed to 2.1 W/m UV-B.
Aliquots, 5 ml, of suspension incubated
2
anaerobically (argon atm.); 30 W/m white
light for assay.
15
-------
Table 4
14
Effect of enhanced irradiation with UV-B on CO^ fixation
and acetylene reduction by Azolla
Irradiation
timea
days
1
2
4
6
Control
14CO
fixe?
24,000
17,800
7,200
4,350
Acetylene
reduced0
450
380
320
350
UV-B enhanced
X
fixed0
20,200
15,200
5,900
4,700
Acetylene
reduced0
300
100
130
100
Visible light, 10 W/m , supplemented with UV-B, 2 W/m .
Vป 7
cpm/g plants (wet)/min in visible light, 30 W/m .
c 2
nmol/g plants Cwet)/h; argon atm., visible light, 30 W/m
16
-------
Figure Legends
Fig. 1. UV killing and photoreactivation of A. flos-aquae. Single,
unfiltered, 8W Rayonet lamps, 15 cm from surface of stirred cell suspension.
Algal protein, 6 yg/ml; total light, 2.7 W/m2.
Fig. 2. UV-B irradiation of A. flos-aquae. Six Rayonet lamps in flat
bank array held 17 on from surface of stirred cell suspension (40 ml,
6 pg protein/ml). Total light, 5 W/m ; UV-B, 2.1 W/m . Cellulose
acetate filter (CA), 10 mil.
Fig. 3. Effect of higher UV-B intensity on A. flos-aquae. Six Rayonet
lamps in curved reflector fixture held 17 cm from surface of stirred
cell suspension (40 ml, 7.6 yg protein/ml). Total light, 12.5 W/m ; UV-
2
B, 5.2 W/m . Cellulose acetate filter, 10 mil.
17
-------
-------
100
CD
o
t-.
CD
O.
= 50
0
UV-B, Dark Plate
-A,
ซa
UY-B, Light Plate
iNo C.A,
U
0
2
l
Control
4 6 8 10
Irradiation, Hours
12
14
2
-------
100
80
o>
C3
l_
-------
FINAL REPORT
IMPACT OF SOLAR UV-B RADIATION ON CROPS AND CROP CANOPIES
L. H. Allen, Jr.
C. V. Vu
R. H. Berg, III
L. A. Garrard
Soil and Water Research Unit
Science and Education Administration
U.S. Department of Agriculture
Agronomy Department, University of Florida
Gainesville, Florida 32611
EPA-IAG-D6-0168
Project Officer:
R.J. McCracken
Agricultural Research, Science and Education Administration
U.S. Department of Agriculture
Washington, D.C. 20250
Prepared for
Environmental Protection Agency
BACER Program
Washington, D.C. 20460
-------
ACKNOWLEDGMENTS
We acknowledge the University of Florida Fruit Crops Department for
the use of greenhouse space and the School of Forest Resources and Conser-
vation for the use of a liquid scintillation spectrophotometer. Also, we
acknowledge the following members of the Fruit Crops Department: Dr. R. H.
Biggs for advice on many facets and especially for providing use of a UV-B
spectroradiometer and calibration information, Dr. S. V. Kossuth for
advice, and Drs. R. A. Sutherland and J. F. Bartholic for providing UV-B
calibration information. We also thank Dr. M. H. Gaskins for use of a
recording spectrophotometer and other laboratory facilities, William
Regenhardt and Julie Bair for laboratory and greenhouse assistance, and .
Monica Linzy for typing the report. Finally, we thank Dr. Harry Cams
and his staff at the USDA Beltsville Agricultural Research Center for their
leadership and guidance in technical aspects of this research effort.
-------
TABLE: OF CONTENTS
Pages
SUMMARY ii -iv
I. GENERAL METHODS AND PROCEDURES 1-1 to 1-7
3 TABLES
5 FIGURES
II. EFFECTS OF SUPPLEMENTAL UV-B ON GROWTH OF SOME
AGRONOMIC CROP PLANTS II-l to II-6
4 TABLES
III. EFFECTS OF SUPPLEMENTAL UV-B RADIATION ON PHOTOSYNTHETIC
PIGMENT CONTENT, LEAF PHOTOSYNTHETIC RATE, AND HILL '
ACTIVITY OF AGRONOMIC CROPS III-l to 111-20
8 TABLES
3 FIGURES
IV. EFFECTS OF SUPPLEMENTAL UV-B RADIATION ON PRIMARY
CARBOXYLATING ENZYMES AND SOLUBLE PROTEINS IN C, AND
C4 AGRONOMIC CROPS f IV-1 to IV-14
9 TABLES
V. UV-B EFFECTS ON ULTRASTRUCTURE OF CROP PLANTS V-l to V-40
1 TABLE *
14 PLATES (57 FIGURES)
-------
. SUMMARY
Effects of UV-B radiation (280 to 320 nm) on 'Bragg1 and 'Altona'
soybeans, 'Little Marvel' peas, 'Rutgers' tomatoes, and 'Golden Cross
Bantam1 sweet corn were investigated under greenhouse conditions.
UV-B irradiance was provided by FS-40 sun lamps filtered with 0.127
mm (5 mil) cellulose acetate film (UV-B enhanced) or 0.127 mm (5 mil)
Mylar film (control). Three different radiation doses were tested: 1.31
(treatment 1^), 1.64 (treatment T2), and 2.25 (treatment TJ UV-B
sun equivalent units (UV-Bseu) where 1 UV-Bseu = 15.98 mWatts m~2
weighted by EXP (-[A - 265)/21.2]2) from 290 to 33C nm. Most effects
were studied within 4 to 7 weeks after seeding.
In soybeans, peas, and tomatoes (C3 plants), exposure to UV-B
doses Tp and T3 caused significant depressions in biomass accumulation,
photosynthetic pigment contents, and leaf C02 uptake rates. Leaf pig-
ment extracts in 80% aqueous acetone from UV-B-treated plants of soybeans
and peas showed considerable increase in absorption; in the wavelength
region of 330 nm to 400 nm with increased UV-B doses. Hill reaction
%
measurements with chloroplast preparations of both soybeans and tomatoes
showed significant reductions when seedlings were exposed to 2.25
UV-B . Significant inhibitions of RuDP-Carboxylase were obtained in
soybean leaf extracts at all three UV-B doses and in tomato leaf extracts
at Tp and T~. An apparent decrease in soluble proteins was also observed
in soybean leaf extract while higher levels of proteins were present in
UV-B-treated tomato leaves.
-n-
-------
In sweet corn (C. plant), seedlings exposed to 2.25 UV-B
had significantly lower biomass accumulations than those of the con-:
trols. Plant height and leaf area gradually decreased with increasing
levels of UV-B radiation. Only corn seedlings exposed to the highest
treatment (2.25 UV-B ) showed a significant inhibition in leaf photo-
ScU \
\
synthetic rates. Activities of PEP-Carboxylase in crude extracts from
corn leaves were significantly suppressed under the two highest UV-B
doses (1.64 and 2.25 uv-Bseu)- Although not statistically significant,
some stimulation of PEP-Carboxylase activity and photosynthetic rate
was obtained in corn plants exposed to 1.31 UV-B . No differences
in proteins of corn among treatments and controls were detected.
Continued exposure of soybean and pea seedlings to UV-B radiation
caused development of abnormal leaf pigmentation, such as leaf chlorosis
and bronzing, which increased in severity with increased doses of UV-B
radiation. In addition, phenomena such as distortion of leaf blades and
reduction of leaf sizes were commonly seen in the most intense UV-B
treatment (T3). Light microscope observations of "Bragg1 soybean leaf
tissue showed that chlorosis and bronzing were limited primarily to
palisade cell layers. Often there was a sharp border separating chloro-
tic and green pigmentation areas. This border was demarcated by major
veins. Chlorosis and bronzing pigmentation patterns indicated .they may
be caused by a compound mobilized in vascular tissue. This compound may
cause a general alteration in phenol metabolism in response to enhanced
UV-B. Electron micrographs showed that there was a substantial reduction
in the amount of chloroplast lamellae and starch content in the
palisade cells of chlorotic areas, whereas green tissue from the same
-iii-
-------
leaf showed no abnormal structures. Spongy mesophyll tissue in the
chlorotic regions contained green chloroplasts of normal size, with
other organelles being similar in appearance to those in the controls.
Bronzing pigmentation initially occurred in the cell wall regions of
adaxial epidermal cells, and later appeared in the walls of palisade
cells. Bronzed cells showed collapsed walls and degraded cytoplasm.
The degraded quality of plastids in the palisade cells constituted
another distinctive feature of bronzed leaf mesophyll tissue. Control
tissue contained typical (chlorophyllous) palisade cells, whereas
a variety of cell types, based primarily on the ultrastructure of .
their plastids, were found in bronzed palisade tissues. These types
were referred to as "vesiculate", "lamellate", "alamellate", and
"lytic" cell types. The lytic cell type was the most commonly found
cell type in palisade layers of bronzed areas. This type showed large
vacant areas in transverse sections.
The presence of mixed cells (containing more than one type of pla-
stid), as well as plastid structures found in some cell types, indi-
cated that UV-B enhancement could be causing lesions in plastid nu-
cleic acids and/or proteins.
No visual development of chlorosis or bronzing was found in corn
leaves. At the highest level of UV-B radiation, corn leaf tissue ap-
peared to be unaffected by UV-B enhancement. On the ultrastructural
level, no deleterious effects were apparent in the structure of cell
organelles in bundle sheath and mesophyll cells, as compared to
the control tissue.
-IV-
-------
SECTION I
GENERAL METHODS AND PROCEDURES
The purpose of these studies was to investigate the effects of
higher levels of solar ultraviolet radiation in the 280 to 320 nm band-
width (UV-B radiation) on agronomic crops. Several crops were grown
and irradiated with different levels of UV-B radiation under greenhouse
conditions in order to provide data for the assessment of plant responses
to increases in UV-B radiation that would reach the earth's surface if
man-induced (or natural) perturbations result in a decrease of strato-
spheric ozone concentrations. At the end of each experimental period,
measurements or analyses were performed to relate treatment to growth,
photosynthesis and its component biochemical reactions, and ultrastruc-
ture of these crop plants.
Procedures that were used to set up UV-B enhancement regimes in the
greenhouse are covered in this section. These procedures include materials
used, environmental conditions, and measurements and computations of ir-
radiance outputs of filtered UV-B lamps (Westinghouse FS-40 sun lamps)-'
in the UV-B wavelength range. Details on specific experiments, analyses,
and results appear in the following sections.
Mention of-this proprietary product, or any other proprietary product
in this report, is for the convenience of the reader only, and does
not constitute endorsement by the U.S. Department of Agriculture, the
U.S. Environmental Protection Agency, or the University of Florida.
1-1
-------
1) Plant Materials and Greenhouse Regime
Soybeans (Glycine max L. cv. 'Bragg' and 'Altona'), peas (Pisum
sativum L. cv. 'Little Marvel'), tomatoes (Lycopersicum esculentum L.
cv. 'Rutgers') and sweet corn (Zea mays L. cv. 'Golden Cross Bantam1) were
selected for these UV-B effect investigations because of their agronomic
and economic importance. Hhree sequential seedings were investigated
at different times as follows: the first seeding on May 6, 1977 for
'Bragg1 and 'Altona1 soybeans and for 'Little Marvel1 peas; the second
seeding on July 20, 1977 for 'Bragg' soybean and 'Rutgers1 tomatoes;
the third seeding on October 4, 1977 for swe.et corn and on October 12,
1977 for 'Bragg1 soybean. Seeds for each cultivar or species were
planted directly in 15-cm diameter plastic pots (3 to 5 seeds/pot) con-
taining a mixture of equal proportion of vermiculite and potting soil,
and were placed on tables in a greenhouse.
Light fixtures containing two Westinghouse fluorescent FS-40 sun
lamps and filter systems were suspended above the pots to provide sup-
plemental UV-B fluxes (Figure 2). Sun lamp radiation was filtered
either through 0.127 mm (5 mil) UV-B radiation transmitting cellulose
acetate (UV-B enhanced) orx0.127 mm (5 mil) UV-B radiation absorbing
Mylar S (Mylar control). For comparative evaluation in some experi-
ments, a second set of control plants were also grown at the same time
'in the greenhouse without exposure to any filtered sun lamp systems (no
UV control). Starting from the day of seed planting, the FS-40 lamps
were turned on for 6 hrs daily, from 10:00 EOT to 16:00 EOT (9:00 EST to
16:00 EST). Cellulose acetate filters were changed twice a week. - UV-B flux
densities in each treatment were checked daily and distances between lamps
1-2
-------
and plant apex were adjusted to ensure that seedlings or plants in each
specific treatment received the desired experimental dose of UV-B radia-
tion. For the controls, the distance between Mylar-filtered lamps and
plant apex were adjusted to the same distances of the corresponding
cellulose acetate-filtered treatments. No artificial light sources were
used to extend greenhouse daylength or to supplement greenhouse daylight
that was natural sunlight transmitted through the lascolite greenhouse
roof. The midday photosynthetically active radiation (PAR 400 to 700 nm)
-2 -1
in the greenhouse was about 450 to 500 yE m sec above the sun lamp
-2 -1
fixtures and 220 to 250 y E m sec at plant height under the lamps.
Temperatures inside the greenhouse during the period of growth of soybeans,
peas, and tomatoes of the first and second seeding fluctuated between 20ฐC
(night time) and 35ฐC (daytime), and those during the growth of sweet corn
and .'Bragg' soybean of the third seeding changed from as low as 3ฐC (night
time) to 30ฐC (daytime). Humidities averaged from 95% (night time) to
40% (daytime). The greenhouse was cooled during the day by forced draft
evaporative cooling. During the growth period, plants were checked and
watered daily to ensure adequate moisture. Liquid fertilizers were applied
%
weekly, starting from the second week after seed planting, at a rate
of 0.6 g of 20-20-20 Sunniland fertilizer per pot. Ten days after germi-
nation, seedlings were thinned to one plant per pot to ensure uniform
;
seedlings for each set of experiments.
At the end of each predetermined experimental period of growth, typi-
cal plants having similar size in each treatment were chosen for growth
analyses or photosynthetic measurements. Samples of fresh leaves were
selected and used for analyses and studies of photosynthetic component
1-3
-------
1 reactions and ultrastructure.
1 . .
: 2) Measurements and Computations of the Irradiance Output (290 -
1 330 nm) of FS-40 Sun Lamps
I On April 28, 1977, UV-B flux densities were measured with a Gamma
Scientific Spectroradiometer at ground level under a clear sky at
the Horticultural Unit, Institute of Food and Agricultural Sciences,
University of Florida, Gainesville, Florida. The Spectroradiometer
was connected to a Hewlett-Packard computer system to acquire and pro-
cess the data. Data scans from 280 to 340'nm were collected at 30-min
intervals, starting at 7:35 EST and ending at 15:02 EST. Unweighted
UV flux densities were printed at 1-nm intervals in units of
Watts m"2 nm"1. A weighting function, EXP(-[x-265)/21.2] ), was used
to simulate DNA absorption (Cams ertaK, 1977), and weighted flux
-2 -1
values were also printed at 1-nm intervals in units of mWatts m nm .
This weighting function has been referred to as A z 21. Both unweighted
and weighted UV flux densities were summed over the 280 to 340 nm wave-
length range for each scan (Table 1). "Standard" solar day unweighted
and weighted flux density curves were extrapolated to early and late
hours of the day (Table l.^Figure 1).
In order to obtain the whole day ir.radiance in unweighted Watts*sec
2 -2
m and weighted mWatts-sec m , both the unweighted and weighted UV-B
flux densities were summed over each 30-min observation (including extra-
polated and interpolated observations), multipled by 30 min per observa-
tion, and multiplied by 60 sec per min. UV-B unweighted and weighted
flux densities were then computed for a "square value", 6-hr equivalent
period (Figure 1) by dividing the above whole-day irradiance by the
number of seconds in 6 hrs (6 x 60 x 60).
1-4
-------
We also compared the A E 21 weighting function with another one
developed by Cams e_t\al_. (1977). This function, termed A E 9, is
[1/4 (x/Xo)9]4 x EXP[4-(x/Xo)9] where Xo = 228.178 nm, and the function
has a maximum value at about 266 nm. Weighted UV-B flux densities
based on 5-nm intervals were computed as shown above. This weighting
function was not used to Express UV-B treatment levels in this report,
but are included" for comparisons. Results of these computations were:
t
Whole-day Irradiance 6-hr Flux Density
Unweighted Weighted Unweighted Weighted
(Watts sec m"2) (mWatts sec m"2) (Watts m"2) (mWatts nf2)
227.8 xJO3 345.1 x TO3 (A I 21) 10.55 15.98 (A E 21)
87.2 xlO3 (A E 9) 4.04 (A E 9)
Thus, the averaged UV-B weighted flux density for this 'Gaines- .
ville standard' solar day (April 28, 1977) equals 15.98 mWatts m
based on the earlier weighting function. This value was adopted as
'standard1 UV-B sun equivalent unit (seu) and UV-B enhancement was
expressed as UV-Bseu where 1 UV-Bseu = 15.98 mWatts m" .
Cams (personal communication) found that the 'Beltsville
_2
standard1 sun gave;, a UV-B of 3.06 mWatts m based on the latter
weighting function. Our UV-B based on the 'Gainesville standard'
_?
sun and the latter weighting function was 4.04 mWatts m .
Supplemental UV-B irradiance was provided by means of Westing-
house FS-40 fluorescent sun lamps filtered with 0.127 mm (5 mil) of
UV-B transmitting cellulose acetate (Transil Wrap Co., Doraville,
Georgia). Two 40-watt FS-40 tubes were mounted in a 1.22-m fixture
and one layer of cellulose acetate filter was clamped under the
1-5
-------
n
fluorescent tubes to the edges of the fixture reflector (Figure 2).
\ All measurements were taken inside the greenhouse after 20:00 EOT
i
(19:00 EST). UV-B spectral energy flux densities were measured
! with a Gamma Scientific Spectroradiometer which was set up with
sensor oriented perpendicular to the fluorescent tubes directly
below the midpoint of the tubes. The lamps that had been aged for
100 hrs were turned on for about 15 to 20 min before actual measure-
ments were started. The Spectroradiometer was zeroed and readings
in millivolts were taken at 5-nm intervals from 280 to 330 nm. Different
flux densities at twelve different distances between the spectre-
radiometer sensor and sun lamps were obtained by varying the height
of the lamp fixture hanging above. Readings in equivalent sunburn
units (S.U. hr~ ) at each corresponding distance were also taken at
the same time with a Solar Light Meter Model SSI 7880 (Solar Light
Co., Philadelphia). This portable instrument was used for daily
checks of the UV-B irradiance output. At each calibration distance,
the Spectroradiometer output was read at 5-nm wavelength intervals
from 280 to 330 nm. These readings were converted to UV-irradiance,
and thence to the A E 21 weighted irradiance by EXP(-[x-265)/21.2]2,
and the total irradiance from 290 to 330 nm was computed (Table 2).
..Figure 3 shows the total weighted irradiance in the wavelength
region 290 to 330 nm as a function of distance. Correlation between
total UV-B weighted irradiance and sunburn units was almost linear
(Figure 4). Values in sunburn units were also plotted as a function
of distance from sensor to middle of the tubes (Figure 5) and this
curve was found convenient for daily checks of the radiation output
1-6
-------
1
1 from FS-40 lamps.
1 We computed the A E 9 weighted irradiances at each distance
; for each 5-nm interval by multiplying the irradiances in Table 2
i by the ratio of the A E 9/A E 21 weighting function (Table 3).
From these data we found that the ratio of the average weighted
irradiance based on the A E 9 function to that based on the A I 21
function was 0.525. This factor could be applied to the left
ordinate of Figure 3. We also found that the average ratio of
the UV-Bseu based on A z 9 to the UV-B based on A E 21 was 2.08.
This factor can be applied to the right ordinate of Figure 3 to
compute the UV-B based on the A E 9 weighting function.
Three following UV-B dose treatments based on the A E 21
weighting function were used as appears in the experimental methods
and results of the next sections: 1.31 UV-B eu for treatment TI,
1.64 UV-B for treatment T2, and 2.25 UV-B$eu for treatment T3.
These treatments correspond to 2.72, 3.41 , and 4.68 UV-B , respec-
tively, based on the A E 9 weighting function. These latter values
are given for reference, and will not be used in this report.
%
LITERATURE CITED
1) Cams, H.R., R. Thimijan, and J.M. Clark. 1977. Outline of
irradiance distribution of UV fluorescent lamps and combinations.
In: Symposium on Ultraviolet Radiation Measurements for Environ-
mental Protection and Public Safety (Program and Abstracts) Na-
tional Bureau of Standards, Gaithersburg, Maryland. June 8-9,
1977, 118 pp.
1-7
-------
TABLE 1
SOLAR RADIATION AT GROUND LEVEL AS MEASURED WITH A GAMMA SPECTRORADIOMETER
ON APRIL 28, 1977 AT THE HORTICULTURAL UNIT IN GAINESVILLE, FLORIDA
Time
7:05
7:35
8:05
8:35
9:05
9:35
10:05
10:35
11:05
11:35
12:05
12:35
13:05
13:35
14:02
14:32
15:02
15:35
16:05
16:35
17:05
SUM
_p
Unweighted Flux (W m _)
0.800 (extrapolated value)
1.726
2.565
3.652
4.808
5.900 (interpolated value)
7.003
7.767
8.560
9.308
9.665
9.796
9.658
8.922
8.500
7.667
6.660
5.330 (extrap. value)
4.000 (extrap. ^value)
2,800 (extrap. value)
1.470 (extrap. value)
126.557 W m
-2
_p
Weighted Flux (mH m" .)
0.400 (extrap. value)
1.336
2.288
3.663
5.618
7.850 (interp. value)
10.070
12.261
14.070
16.366
17.212
17.478
17.044
15.390
13.450
11.226
9.288
7.120 (extrap. value)
5.150 (extrap. value)
3.250 (extrap. value)
1.200 (extrap. value)
191.73 mW m
-2
unweighted = 227.8 x 103 W-sec m l weighted = 345.1 x 10 mWซsec m"
-------
TABLE 2
WEIGHTED UV-B IRRADIANCE (A E 21) AS A FUNCTION OF WAVELENGTH AND DISTANCE OF LAMPS FROM
THE SPECTRORADIOMETER
Distance^ 18.40 20.65 27.95 28.60 33.34 33.65 39.37 41.30 52.38 54.60 64.15 65.10
Wavelength
290
295
300
305
310
315
320
325
330
SUM^/
0.900
2.506
3.489
2.159
0,975
0.347
0.093
0.020
0.004
TO ,493
0.930
2.378
3.179
1.971
0.891
0.310
0.083
0.018
0.004
9.764
0.845
1.868
2.519
1.533
0.686
0.242
0.065
0..014
0.003
7.775
0.507
1.868
2.398
1.428
0.650
0.223
0.057
0.013
0.002
7.146
0.845
1.784
2.223
1.340
0.599
0.210
0.057
0.012
0.002
7.072
0.789
1.670
2.142
1.290
0.582
0.204
0.055
0.012
0.002
6.746
0.732
1.501
1.846
1.102
0.495
0.172
0.047
0.010
0.002
5.907
0.479
1.472
1.751
0.991
0.448
0.152
0.041
0.009
0.002
5,345
0.676
1.189
1.334
0.811
0.357
0.127
0.035
0.008
0.001
4.538
0.394
1.076
1.266
0.728
0.327
0.109
0.029
0.006
0.001
3.936
0.394
0.877
T,050
0.581
0.261
0.088
0.024
0.005
0.001
3.281
0.620
0.934
1.064
0.631
0.282
0.099
0.027
0.006
0.001
3.664
Distance perpendicularly from center of sensor to midpoint of lamp tubes in cm.:
2/ -2-1
Sum, mWatts m nm
3/ -2
^ Total = Sum x 5nm, mWatts m .
-------
TABLE 3
WEIGHTED UV-B IRRADIANCE (A Z 9) AS A FUNCTION OF WAVELENGTH AND DISTANCE OF LAMPS FROM
THE SPECTRORADIOMETER
Distance^/ 18.40 20.65 27.95 28.60 33.34 33.65 39.37 41.30 52.38 54.60 64.15 65.10
Wavelength
290
295
300
305
310
315
320
325
SUM?/
TOTAL-7
0.777
1.773
1.812
0,723
0.180
0.029
0.003
-
5.297
26,49
0.803
1.683
1.651
0.660
0.164
0.026
0.003
4.990
24.95
0.730
1.322
1.308
0.5-13
0.127
0.020
0.002
. -
4.022
20.11
0.438
1.322
1.245
0.478
0.120
0.019
0.002
-
3.624
18.12
0.730
1.263
1.154
0.449
0.111
0.017
0.002
-
3.726
18.63
0.681
1.182
1.112
0.432
0.107
0.017
0.002
-
3.533
17.67
0.632
1.062
0.959
0.369-
0.091
0.014.
0.001
-
3.128
15.64
0.414
1.042
0..909
0.332
0.082
0.013
0.001
-
2.793
13.97
0.584
0.841
0.693
0.272
0.066
0.011
0.001
-
2.468
12.34
0.340
0.761
0.657
0.244
0.060
0.009
0.001
-
2.072
10.36
0.340
0.621
0.545
0.195
0.048
0.007
0.001
-
1,757
8.79
0.535'
0.661
0.552
0.211
0.052
0.008
o.ooi
-
2,020'
10.10
Distance perpendicularly from center of sensor to midpoint of lamp tubes in cm.
2/ -2 -1
Sum, mWatts m nm . .
V -2
z* Total = Sum x 5nm, mWatts m .
-------
Wt, Flux
Total Flux
mW m
16
12
8
4
-2
0705
W m
-2
Wt. Flux
/2SO to 340 n
m
Total Flux
280 to 340 nm
Gainesville
Day April 28,1977
i \ \ i t i i i i i
12
10
8
6
4
2
1005 1205 1505 1705
Time (EST)
Figure 1. Weighted flux density and total (unweighted) flux density of UV-B radiation on April
28, 1977, at Gainesville, Florida.
-------
(End view)
Adjusts for Height
Fixture
FS 40 Sun Lamps
30cm
(Side view)
Filter
kl
&\
s ^
1
1 122cm \j
^Filter
Tdble for Plants
Figure 2. Setup for UV-B radiation enhancement in the greenhouse.
-------
Irradiance
(mW rrT2)
50
UV-B
40
30
20
o
seu
3
2
r I
20 40 60
Distance from Center (cm)
Figure 3. Weighted UV-B irradiance output and corresponding UV-B
values at different distances from two FS-40 sun lampsseu
(measurements were taken inside the greenhouse after 20:00
. EOT) (1 UV-B$eu = 15.98 mW m-2).
-------
S,U, hr
-I
3
15
25
35
mWatfs m
45
-2
55
Figure 4. Relation between UV-B irradiance from two FS-40 sun lamps and sunburn units.
-------
30 40 50 60
Distance from Center (cm)
Figure 5. Sunburn units of two FS-40 sun lamps as a function of distance.
-------
SECTION II .
I EFFECTS OF SUPPLEMENTAL UV-B ON GROWTH OF SOME AGRONOMIC CROP PLANTS
i
INTRODUCTION
i
Plant biomass accumulation that reflects a summation of effects through
the growth period appears to be one of the best parameters for comparison
and evaluation of plant response to specific experimental treatments. Studies
that were carried out in both field and controlled environment conditions
showed that UV-B radiation significantly reduced growth and biomass accu-
mulation of many plant species (Caldwell e_t a]_., 1975; Biggs and Basiouny,
1975; Sisson and Caldwell, 1976; Van ejfc al_., 1976). In this section,
greenhouse experiments were conducted to deal with growth and development
of some agronomic crops that were exposed to different doses of UV-B en-
hanced irradiation.
EXPERIMENTAL METHODS AND PROCEDURES
Fresh weights and dry weights per plant in the UV-B treated and control
plots were determined for soybeans, peas, and sweet corn. Measurements
were made on soybeans and peas^at 35 days after planting (planting date -
May 6, 1977; harvesting date - June 10, 1977, with 210 hours of exposure
to enhanced UV-B radiation) and on sweet corn at 45 days after planting
(planting date - October 4, 1977; harvesting date - November 18, 1977, with
270 hours of exposure to enhanced UV-B radiation). Plants were carefully
removed from pots and the soil around the roots was gently washed away
with water. The roots, after washing to free them of soil and vermiculite,
were then blotted with paper towels. Each plant was put in an air tight
polyethylene bag and fresh weight was determined within 2 hours after
-1-
-------
collection.
Plant height and total leaf area of sweet corn were also measured
at 43 days after planting. Height of the above ground main stem was taken
from the stem base to the terminal shoot. Length and width in the middle
of each leaf were measured and leaf area was computed, total leaf area per
plant was the summation of areas of individual leaves of the plant.
Dry weight was determined after drying the samples in an oven at
70ฐC for 48 hours. Fresh weights and dry weights were measured for the
whole plant for soybeans and peas, and separately as shoots and roots
for sweet corn.
RESULTS AND DISCUSSION
For purpose of evaluating the response of important agronomic crops
to supplementary UV-B radiation, plants were grown in a greenhouse with
different doses of UV-B radiation. Fresh weights and dry weights of
greenhouse-grown soybean, peas, and sweet corn that were exposed to an
enhanced UV-B irradiation regime are presented in Tables 1 and 2.
The data from these Tables demonstrate that the effects of UV-B
%
radiant energy on growth are dose-related. Fresh and dry weight of 'Soy-
*
beans, peas, and sweet corn were significantly reduced when plants were
grown under high levels of UV-B radiation in the greenhouse. At the
highest UV-B dose of the experiment (2.25 UV-Bseu)ป growth was reduced
to 30-40% of the Mylar control in both soybeans and peas (Table 1).
'Altona' soybean seemed to suffer more severely under UV radiation
than 'Bragg1 soybean, both in fresh and dry weights. No statistical
test was performed as regard to UV response for these 2 cultivars of
-2-
-------
soybeans. 'Little Marvel' pea, being classified as "sensitive" in respect
to UV-B radiant energy (Van ฃt a]_., 1976), also showed highly significant
reductions under 2.25 UV-B . Dry weights in general were reduced to
about the same degree as fresh weights for all three crops.
A general visual observation was that soybean and pea seedlings respond
to continuous UV radiation at 1.64 and 2.25 UV-B . Chlorotic and
seu
bronzing symptoms in leaves that were exposed to UV-B radiation were ob-
served both in peas and in soybeans. Furthermore, soybeans exposed con-
tinuously to 2.25 UV-B .also showed abnormal curvature of the shoots and
distortion of leaves. Some dark brown areas or spots around the vein tis-
sues also appeared in some areas near the central regions of young leaf
tissues. Plants growing under Mylar filter controls were healthy and
similar in appearance to untreated control plants.
In both cultivars of soybeans, dry weights were reduced to a lower
level than fresh weight. Dry matter accumulation of control 'Bragg' soy-
beans irradiated through a Mylar filter was more than twice that of plants
exposed to 2.25 UV-B . The dry weight accumulation of 'Altona' plants
under the same dose of UV was only one third of the Mylar control plants.
\
Also, when irradiated under 1.64 UV-B u, the 'Altona' dry weight was
lower than the 'Bragg', 60% vs. 75% with respect to the Mylar control,
respectively, for the two cultivars. Similar observations were noted in
fresh weight accumulation, 38% vs. 49%, with respect to the Mylar control
at 2.25 UV-B , and 74% to 85% with respect to the Mylar control at
1.64 UV-B , for 'Altona' and 'Bragg', respectively.
At 1.64 UV-B , 'Little Marvel' pea plants showed no significant
differences from the Mylar control in both fresh and dry weight (Table 1).
-3-
-------
HoWever, pea plants under 2.25 UV-B of irradiation accumulated only
one half of the biomass of. Mylar control plants.
In sweet corn, no symptoms of chlorosis or bronzing were observed on
the! entire surface of the leaves of UV-B treated plants throughout the
experimental period. Corn plants under continuous UV-B radiation were
similar in appearance, but not in size, to the Mylar control and no UV
control plants. Plants exposed to UV-B had significantly lower fresh
weights and dry weights than those of the controls (Table 2). From
the control to the highest UV-B exposed treatments, patterns of decrease
in both fresh weights and dry weights of the tops were very similar to
those of the whole plant. Data from Table 2 also showed that UV-B radia-
tion influenced the biomass accumulation of roots, although to a lesser
extent than that of shoots. In the two enhancement treatments of 1.64 and
1.31 UV-B , root biomass was larger than in the Mylar control, but not
*v
larger than the no UV-B treatment.
Significant reductions to 65% in both total fresh weight and dry -
weight relative to the Mylar control and to less than 60% relative to the
untreated control were observed when corn plants were exposed for 44 days
\
to 2.25 UV-B . Biomass accumulation of the Mylar control plants was
less than that of the untreated control plants.
Height and total leaf area measurements of corn are shown in Tables
3 and 4, respectively. Mean values of the plants treated with UV-B radia-
tion differed significantly between treatment and control. Plant height
and leaf area decreased with increasing levels of UV irradiation. Analy-
ses of data showed that these decreases are significant.
Caldwell et al_. (1975) reported a decrease in biomass when field-grown
-4-
-------
soybeans and corn were exposed to a UV-B enhanced irradiance regime that
simulated a 0.11 atm-cm decrease of atmospheric (stratospheric) ozone.
Under greenhouse conditions, UV-B enhancement (a simulation of a 50%
atmospheric ozone depletion) caused a significant decrease in both'plant
fresh and dry weight of 'Little Marvel1 peas, 'Hutton1 soybean, and other
-agronomic crops (Van ejt a]_. ,^1976). 'Pioneer 3364A1 corn also showed
some biomass reduction under this level of UV-B enriched regime. Our
short-term greenhouse experiments indicate the potential of enhanced
UV-B irradiance to significantly suppress growth of sensitive higher
plant species. These results would be used to aid in relating adverse
responses to anticipated increases in UV radiation that could result
from stratosphere ozone depletion.
LITERATURE CITED
1) Biggs, R.H. and P.M. Basiouny. 1975. Plant growth responses to
elevated UV-B irradiation under growth chamber, greenhouse, and
solarium conditions. In: Climatic Impact Assessment Program (CIAP),
Monograph 5, Part 1, U.S. Department of Transportation, 4-197 through
4-249.
. ' *
2) Caldwell, M.M., W.B. Sisson, P.M. Fox, and J.R. Brandle. 1975. Plant
growth response to elevated UV irradiation under field and greenhouse
conditions. In: Climatic Impact Assessment Program (CIAP), Monograph
5, Part 1, U.S. Department of Transportation, 4-253 through 4-259.
-5-
-------
3) Sisson, W.B. and M.M. Caldwell. 1976. Photosynthesis, dark respira-
tion* and growth of Rumex patienti'a L. exposed to ultraviolet irra-
diance (288 to 315 nanometers) simulating a reduced atmospheric ozone
column. Plant Physiol. 58:563-568.
4) Van, T.K., L.A. Garrard, and S.H. West. 1976. Effects of UV-B
radiation on net photosynthesis of some crop plants. Crop Sci. 16:715-
718.
-6-
-------
TABLE 1
EFFECT OF UV-B RADIATION ON FRESH AND DRY WEIGHTS
IN SOYBEANS (TWO CULTIVARS) AND IN PEAS
I/
Species
.'Bragg' soybean
Treatment-
2/
\
'Altona'
soybean
'Little Marvel1
pea
Mylar control
1.64 (T2)
2.25 (T3)
Mylar control
1.64 (T2)
2.25 (T3)
Mylar control
1.64 (T2)
2.25 (T3)
Fresh weight
(g plant'1)
40.09 (100)**a
34.25 (85) b
19.80 (49) c
39.99 (100)**a
.29.40 (74) b
15.23 (38) c
10.53 (100)* a
9.71 (92) a
4.69 (45) b
3/
Dry weight
(g plant"1)
6.15 (100)**a
4.61 (75) b
2.66 (43) c
6.77 (100)**a
4.09 (60) b
2.23 (33) c
1.07 (100)* a
1.04 (97) a
.59 (55) b
Plants were grown in the greenhouse, planted - May 6-, 1977; harvested -
June 10, 1977.
UV-B enhancement dose in sun equivalent units (UV-B ). 1.64 UV-B
seu'
seu
in Treatment T2 and 2.25 UV-Bseu in Treatment T3. Duration of UV-B
exposure was 210 hours.
o /
Numbers in parentheses represent the percentage responses with respect
to the Mylar control. Values with different letters in the same column
are significantly different at the 0.05 (*) or 0.01 level (**) in the
Duncan Multiple Range Test, each cultivar considered separately.
-------
Treatment
No UV control
Mylar control
1.31 (^)
1.64 (T2)
2.25 (T3)
TABLE 2
EFFECT OF UV-B RADIATION ON GROWTH OF SWEET CORN-/
_1 3 /
Fresh weight (q plant )
Top
69.94* a
59.53 ab
5L49" b
Root
13.04* a
10.42 b
11.30 ab
56.07 ab 10.51 b
35.92 .c 9.36 b
Total
77.98 (100)* a
69.95 (90) ab
62.79 (81) b
66.58 (85) ab
45.28 (58) c
Dry weight (n plant" )
Top
5.12* a
4.43 ab
4.00 b
4.21 ab
2.86 c
Root
0.99* a
0.77 be
0.88 ab
0.78 be
0.65 c
Total
6.11 (100)* a
5.20 (85) ab
4.88 (80) b
4.99 (82) ab
3.51 (57) c
- Planted ~ October 4, 1977; harvested - November 18, 1977.
2/
UV-B enhancement in sun equivalent units (UV-B ). Duration of UV-B exposure was 260 hours. No UV control,
i.e. plants grown in the greenhouse without exposure to any filtered sun lamps.
Values in parentheses represent percentage response with respect to the no UV control.
*
Values with different letters in the same column are significantly different at the 0.05 level in a Duncan
Multiple Range Test.
-------
TABLE 3
EFFECT OF UV-B RADIATION ON HEIGHT OF SWEET CORN-/
21
Treatment-
No UV control
Mylar control
1.31 (T^
1.64 (T2)
2.25 (T3)
Plant height (cm)
44.1*
39.9
35.4
37.6
34.4
a
be
de
cd
e
% of control
(100)
(90)
(80)
(85)
(78)
y Planted - October 4, 1977; .harvested - November 16, 1977.
- UV-B enhancement in sun equivalent units (uv~Bseu). Duration of
UV-B exposure was 250 hours.
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 4
EFFECT OF UV-B RADIATION ON LEAF AREA OF SWEET CORN-/
i 2.1
Treatment-
No UV control
Mylar control
1.31 (T,)
1.64 (T2)
2.25 (T3)
Total leaf area
957.0*
893.7
785.7
832.3
607.7
-1 2
plant (cm )
a
ab
b
ab
c
% of control
(100)
(93)
(82)
(87)
(64)
-/Planted - October 4, 1977; .harvested - November 16, 1977.
?/
UV-B enhancement in sun equivalent units (UV-B ). Duration of
UV-B exposure was 250 hours.
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
SECTION III
EFFECTS OF SUPPLEMENTAL UV-B RADIATION ON PHOTOSYNTHETIC PIGMENT CONTENT,
LEAF PHOTOSYNTHETIC.RATE, AND HILL ACTIVITY OF AGRONOMIC CROPS
INTRODUCTION
Photosynthesis is undoubtedly of great importance to growth and yield
of plants. It provides means by which radiant energy is absorbed and used
to produce reducing power and chemical energy for the reduction and trans-
fer of C02 from the free condition to carbohydrates (Hendricks, 1967;
Garrard and Brandle, 1975);
Monochromatic 254-nm radiation (UV-C) has been reported to reduce
growth and inhibit several component reactions of photosynthesis in algae
and some other higher plants (Arnold, 1933; Shavit and Avron, 1963; Jones
and Kok, 1966; Mantai: and Bishop, 1967; El-Mansy and Salisbury, 1971, 1974).
Photobiological data obtained using UV-C radiation can serve only as in-
formation for comparative purpose since there are appreciable quantitative
and qualitative differences in response to UV-B radiation as opposed to
radiation at 254-nm (Caldwell, 1977). Furthermore, the biologically
potent waveband shorter than 280 nm would not be present at the earth's
\
surface even if the ozone layer were reduced to 40% of its present thick-
ness (Green et^ aj_., 1974). UV-B radiation occurs naturally in solar* radiation
reaching the earth and would be intensified if the atmospheric ozone layer
.;
was reduced. Thus, any consideration and investigation of biological
effects of increased solar UV radiation due to reduced atmospheric ozone
should be confined to the waveband between 280 and 315 nm (UV-B) (Caldwell,
1977).
Information and knowledge of UV-B radiation effects of biological
III-l
-------
systems have accumulated during the last few years. UV-B radiation has
been reported to reduce photosynthesis, growth, and biomass accumulation
in a number of agronomic crops and plants (Van e_t al_., 1976; Sisson
and Caldwell, 1976; Brandle et al_., 1977).
The objective of the experiments appearing in this section is to
evaluate the potential effects of an increase in UV-B radiation on photo-
synthesis of selected agronomic crops. Studies include analyses of chloro-
phyll and carotenoid content and measurements of leaf photosynthesis as well
as Hill activity that is associated with the photochemical reactions and
electron transport system in chloroplasts.
MATERIALS AND METHODS
(1) Extraction and determination of chlorophyll and carotenoid
Total chlorophyll and carotenoid content was extracted by a modifi-
cation method as described by Starnes and Hadley (1965). Approximately
0.5 g fresh weight leaf tissues, with midribs removed, of 35-day old 'Altona
and 'Bragg1 soybeans and 'Little Marvel' peas were macerated at full speed
for 3 min in a pre-chilled Sorvall Omni-Mixer in 15 ml of ice cold 80%
aqueous acetone. The supernatant was decanted and vacuum filtered through
one layer of Whatman No. 1 paper in a Buchner funnel. The residue was
homogenized a second time for 2 min with 10 ml of 80% acetone and the homo-
genate was quantitatively transferred to the funnel and vacuum refiltered
to ensure that all chlorophyll and carotenoid had been extracted. The
filtrate was brought to 100 ml with 80% acetone solution in a volumetric
flask and allowed to incubate at room temperature for 1 hr. A 10-ml ali-
quot was taken and centrifuged at 1,000 & for 5 min. The absorbance of the
III-2
-------
supernatant was read at 663, 652, and 645 nm with a Model 25 Beckman
Spectrophotometer. The concentrations of total chlorophyll and those of
chlorophyll a^ and b^ were calculated using equations of Arnon (1949). These
i
values were then used to compute the chlorophyll content on a fresh weight
basis. The approximate content of carotenoids in the acetone extract was
determined by measuring the absorbance at 480 nm and calculated according
to equation described by Liaaen-Jensen and Jensen (1971).
The absorbance of the 80% acetone leaf pigment extract was then re-
corded continuously from 710 nm to 330 nm with the Model 25 Beckman Spectro-
photometer at a wavelength scanning speed of 100 nm/min and at a 5 cm/min
chart speed. The absorbance value at 665 nm was arbitrarily chosen as
unity and the absorbance values at other wavelengths were expressed rela-
tive to it.
(2) Photosynthesis measurements
Leaf net photosynthetic rates were measured on soybeans, tomatoes,
and sweet corn by net (X^ uptake of whole, attached leaves in an air-sealed
leaf chamber as described by Wolf et^ al_. (1969). Leaves that were selected
for photosynthetic measurements were the center leaflets of the top 3rd and
4th trifoliate (soybeans), or those of the top 4th and 5th multifoliate
(tomatoes). The corresponding lateral leaflets were removed before measure-
ments and resultant wounds were sealed with petroleum jelly. For sweet
corn, fully developed leaves at the top 2nd and 3rd position were used for
experiments.
C0? uptake rates were measured on 38-to 42-day old soybean and tomato
plants and 35-day old sweet corn. The Plexiglas chamber containing the
leaf was attached to a closed gas-flow system containing a Model 215A
III-3
-------
Beckman IR gas analyzer, pumps, and flow meters. Air was circulated by a
pump sequentially through a flask containing water to provide humidity,
through the leaf chamber, through a CaSO, desiccant to dehumidify the air
stream, through the IR gas analyzer, and back to the pump. Photosynthe-
tically active radiation (PAR) was furnished by a combination of a 400-Watt
Lucalox lamp (General Electric LU 400/BU) and a 400-Watt Multi-Vapor
Mercury lamp (General Electric MV 400/BUH) mounted in a single reflective
fixture. The lamp irradiance was filtered through 6.5 cm of circulating
chilled water. The PAR photon flux density was measured with a Lambda
Instruments quantum sensor, Model LI-185. PAR flux density was controlled
by adjusting the distance between the light source and leaf chamber, or with.
neutral (white) cheesecloth between the light source and leaf chamber.
Temperature inside the leaf chamber containing the whole attached leaf
during measurement was determined by a constantan-copper thermocouple in-
serted into the abaxial side of the leaf. Leaf areas were obtained
after C02 uptake measurement by placing leaves against blue print paper
and exposing them to light for about 1 min. The leaf imprint was then cut
out and measured with a leaf area meter. Net C02 exchange rates were ex-
-2 -1
pressed as mg C02 uptake dm hr .
(3) Hill activity measurement
Leaf samples of 6-week old 'Bragg1 soybeans and 'Rutgers' tomatoes,
with midribs removed, were macerated in a cold Sorvall Omni-Mixer with ice-
cold extraction solution consisting of 50 mM phosphate buffer (pH 7.6),
0.35. M sucrose, 2 mM EDTA-Na2, 5 mM MgClg, 1 mM MnCl2> 20 mM Na-ascorbate,
and 0.1% BSA (w/v). For each gram of plant material, 5 ml of extraction
medium was used. Homogenization was performed at full speed during two
III-4
-------
20-sec periods, separated by a 2-min interruption. The homogenate was then
strained through 8 layers of cheesecloth and filtered through 20 ym nitex
nylon screen. These steps were performed as fast as possible in cold
conditions within an ice chest. The suspension was centrifuged at 1,000 g
for 5 min at 4ฐC and the supernatant was quickly separated from the chloro-
plast pellet and discarded. The pellet was resuspended in a suspension
solution having composition similar to the grinding solution except that
Na-ascorbate and BSA were omitted. The chloroplast suspension was stored
in ice and assayed for Hill activity.
Hill activity measurements were performed at room temperature (=22ฐC)
in cuvettes of 1 cm light path. The total 3 ml reaction mixture contained
50 mM phosphate buffer (pH 7.6), 2 mM EDTA-Na2, 5 mM MgCl2, 1 mM MnClg,
0.025 mM 2,6-dichlorophenolindophenol (DCPIP), and chloroplast suspension
(8 to 14 yg of chlorophyll). Light was provided by a 750-W tungsten pro-
-2 -1
jector bulb giving a PAR photon flux density of 800 yeinsteins m sec
at the surface of the cuvette. Absorbancy of the reaction mixture was de-
termined at 590 nm with a Model 25 Beckman Spectrophotometer immediately -
before and immediately after being irradiated for 30 sec at room tempera-
ture. Hill activity was expressed as ymoles of DCPIP reduced mg chloro-
phyll hr"1.
Chlorophyll in the chloroplast suspension was determined with slight
modification by a method described by Mbaku (1976). Aliquots of 0.4 ml
of chloroplast suspension were put in test tubes, 0.6 ml of 100% acetone
was added and the contents were stirred vigorously with a Vortex mixer.
Test tubes were covered with parafilm and placed in the dark for 10 min.
Five ml of 80% acetone was added, and the contents were stirred and placed
111-5
-------
JIT the dark for another 10 min. This was repeated, as necessary, until
the homogenate residue was visually white, indicating that all chlorophyll
was extracted. Mixtures were then spun at 1,500 g for 15 min, supernatants
were taken up and absorbances at 663, 652, and 645 nm were measured.
Total chlorophyll content in mg/ml of chloroplast suspension was then com-
puted based on Arnon's equations (1949):
Chi (mg/ml) = 0.15 [(2.02 x A645) + (0.802 x A663)]
or
0.15 (A,,, x 100)
Chi (mg/ml) = ง|^
RESULTS AND DISCUSSION
(1) Pigment content
Both cultivars of soybean and 'Little Marvel' pea plants exposed to
UV-B radiation for 200 hrs generally had lower chlorophyll content than
those of Mylar control (Table 1). Increasing the UV-B level from 1.64 to
2.25 UV-B resulted in significantly reducing the total chlorophyll con-
tent, from 75% to 65% of the control in 'Bragg' soybean, and from 83% to
80% of the control in pea. Chlorophyll content in 'Altona1 soybean was
78% of the control at the dose of 1.64 UV-B ฃU of UV radiation, and this
inhibition remained unchanged at higher level of radiation (2.25 UV-B ).
Chlorophyll a_, which accounted for 70% to 80% of total chlorophyll in both
soybean and pea, decreased in much the same pattern as the total chlorophyll
with increasing level of UV-B radiation. The ratio of chlorophyll a_ to
chlorophyll j), except the case of 'Bragg' soybean, was not affected.
Table 2 showed the effect of UV-B irradiation on carotenoid content
in acetone extracts from leaves of soybeans and peas. Both UV-B doses
III-6
-------
significantly reduced the total amount of carotenoids in all species tested.
Inhibition was highest in 'Bragg1 soybean and slightly less in 'Altona1
and 'Little Marvel1 pea. Also in 'Bragg' soybean, difference between the
two UV-B levels was significant.
When soybeans and peas were'grown under a UV-B enhancement regime,
a difference in the absorption spectrum in the wavelength region 330 nm-
400 nm was observed when the 80% acetone leaf pigment extract was scanned
from 710 nm to 330 nm. Absorption values of pigment extracts from 400 nm
down to 330 nm increased with higher doses of UV-B exposure (Figures 1, 2,
and 3), showing that the pigments in acetone solution extracts from the
UV-B treated plants absorbed more radiation near the UV-B waveband (280
to 320 nm) than those of the control. Interference by acetone absorption
in the ultraviolet region below 330 nm prevented determinations of the ab-
sorption spectra of the pigment solutions below this wavelength.
Reductions in total chlorophyll as a result of exposing plants to UV-C
radiation have been reported in soybean (Tanada and Hendricks, 1953), tobacco
(Wu et al_., 1973; Skokut e_t al_., 1977), onion (El-Mansy and Salisbury, 1974),
and other plant species (El-Mansy and Salisbury, 1971). When bean and
cabbage were grown in a greenhouse under a UV-B regime designed to simulate
a 50% ozone depletion, no reduction of chlorophyll was found in either
species (Thai, 1975). Plants exposed for 300 hrs under the same UV-B dose
in a growth chamber had significant reductions of 26% in bean and 14% in
cabbage- with respect to the control.
In our greenhouse experiments, visual symptoms such as discoloring
and bronzing in leaf tissues resulting from UV-B damage were common in
soybeans and peas. Mechanisms through which total chlorophyll was reduced
III-7
-------
by UV-B radiation, as expressed by chlorosis or bronzing of leaves, would
indicate many possibilities. Observations of increased absorption of
the acetone pigment extract near the UV-B waveband would indicate that the
chlorophyll pigments per se or chlorophyll-protein complexes may be to
some degree a protective adaptation of the leaves to UV radiation. These
protective pigments would be the site of absorption of a great part of UV
radiation impinging the leaves (Basiouny and Biggs, 1975). The reductions
in chlorophylls and other pigments (carotenoids) may result either from
inhibition of synthesis or from breakdown of the pigments or their pre-
cursors (El-Mansy and Salisbury, 1974). UV-B may also induce non-enzymic
photooxygenation of the chlorophylls and carotenoids, resulting in accumu-
lation of these pigments as oxygenated forms (Monties, 1974). Whether
UV radiation directly affects molecular and/or cellular systems is not
well-documented at the present time. Questions on reductions in photo-
synthetic pigments under UV-B radiation are not clear currently and are
still open for further investigations.
(2) Photosynthesis
Rates of net photosynthetic CC^ uptake for leaves of control plants
and plants which received different doses of UV-B radiation are given in
Tables 3 and 4 for soybeans, Table 5 for tomatoes, and Table 6 for sweet
corn. Mean net photosynthetic rates of the UV radiation-treated plants
were in general depressed below the controls. The highest value of
significant depression was about 50% with respect to the control for
'Bragg1 soybean under 1.64 UV-B (Table 4). As can be seen in Tables
4.and 5 the rates of carbon dioxide uptake were unusually low in leaves
of 'Bragg1 soybean and tomatoes of the second seeding. We cannot explain
III-8
-------
this phenomenon. Many uncontrolled factors and conditions may have af-
fected both the control and the UV-B treatments during the summer experi-
ment. Environmental conditions during the period of plant growth, such
as air and soil temperature, and light intensity, are among important
factors greatly affecting the rates of photosynthesis. Net CCL uptake
-2 -1
rates of leaves as low as 1.1 and 5.3 mg (XL dm hr were reported when
soybean plants were grown in a growth chamber with a light intensity of
1,000 Lux and 4,200 Lux, respectively (Bowes ejt al_., 1972). These rates
-2 -1
increased up to 24.4 mg (XL dm hr at 20,000 Lux of maximum light during
growth. Leaf net photosynthetic rates of summer and winter grown green-
house plants differ significantly. Hesketh (1968) found higher rates
from plants grown during the summer months under his greenhouse conditions.
The leaves of all our treatments of both soybeans and tomatoes turned pale
green while growing in the greenhouse before the (XL exchange measurements
were made. Unfortunately, we do not have photomicrographs of sections.
Also it should be mentioned that the photon flux density (PAR) used during
the C02 uptake measurements of plants from the first seeding (Table 2) was
-2 -1
1,400 yE m sec and the temperatures inside the leaf chamber (under the
leaf) as determined by a thermocouple were 30ฐ-31ฐC. During the measure-
ments of (XL uptake rates for 'Bragg1 soybean and 'Rutgers' tomatoes from
-2 -1
the second seeding (Tables 4 and 5), the PAR was 700 yE m sec , and the
temperature inside the leaf chamber averaged only about 25-26ฐC. Bowes
eฃ al_. (1972) showed that soybeans grown under high irradiance conditions
gave.high leaf photosynthetic rates and required high irradiance for light
saturation, whereas leaves from soybeans grown at low irradiances had low
maximum rates of photosynthesis and showed light saturation of low
III-9
-------
irradiance.
Disregarding the unexplained factors that caused significantly
lower rates of photosynthesis of plants from the second seeding, compared
with the other seedings, UV-B radiation decreased the rates of photosyn-
thesis in both 'Bragg1 soybean (Table 4) and 'Rutgers' tomatoes (Table 5).
. . ' ^ -i
Under 2.25 and 1.64 UV-B leaf net photosynthesis was significantly re-
duced in both plant species. Tomato leaves irradiated with 1.31 UV-B
also showed significant reduction in photosynthesis while similarly
treated 'Bragg' soybean leaves did not. No significant differences among
the three controls were observed. In both species, mean values of both
Mylar controls for treatment T, (2.25 UV-BCOI1) and T, (1.31 UV-BCQ11) were
ซ5 ScU , I Scu
less than those of no UV control; also the photosynthetic rates of Mylar
control for T, was slightly higher than those of Mylar control for T- but .
not significantly different. This may be due partly to the shading of
solar irradiance by the lamp fixtures which would result in less natural
light received by the Mylar control plants than by the no UV control plants.
In tomatoes, no significant differences among UV treatments were observed.
In 'Bragg' soybeans however, there was significant difference (at 0.01 level)
between the 2.25 UV-Bseu and the 1.64 UV-B$eu treated leaves; plants that
received 1.64 UV-B had much lower photosynthetic rates than those treated
with 2.25 UV-& (Table 4). Also from the first seeding, 'Altona' soybean
leaves irradiated with 1.64 UV-B had significantly lower values of net
C09 uptake than those that received a higher dose of UV-B (2.25 UV-B ).
ฃ o fป*
These unexplainable increases in C02 uptake rates in soybean plants exposed
to 2.25 UV-B$eu with respect to plants treated with 1.64 UV-Bseu were not
well documented for further comment at present time.
111-10
-------
In corn, the UV-B radiation-treated plants (1.31 UV-B ) exhibited
a significant increase in photosynthesis rates per unit leaf area over plants
in other treatments and in controls (Table 6). Also, plants receiving
1.64 UV-B have photosynthetic rates slightly higher than those of the
Mylar control (but not significantly different). Only the treatment of
plants irradiated with 2.25 UV-B showed significant reductions in net
photosynthesis when compared to the no UV control plants. With regard
to the per-plant total leaf area, as can be seen in Table 4 of Section II
the total leaf area of corn plants receiving 1.31 UV-B was lower than
that of the Mylar control and significantly lower than that of the no
UV control. Plants irradiated with 1.64 UV-B were also lower in total
leaf area with respect to both controls. In plants exposed to a 2.25
UV-B regime, significant reductions to 64% and 68% in leaf area relative
to the no UV control and the Mylar control, respectively, were observed.
Information concerning the efects of UV-B radiation on photosynthesis
has been accumulating in the past few years. Studies using a wide range
of plant species have shown that an enhanced UV-B radiation regime does
effectively depress leaf net photosynthesis rates. Van et^ al_. (1976) mea-
sured the leaf photosynthetic rates of several agronomic plants which
were grown in the greenhouse and in growth chambers under 6 hrs of daily
exposure during plant growth to UV-B irradiance equivalent to a 50% ozone
depletion. Of the species tested in the greenhouse, mean net photosynthetic
rates of UV radiation-treated plants of pea, cabbage, collard, soybean,
oat, and rice were significantly depressed below the control plant photo-
synthetic rates. Corn plants in the UV-B enhanced treatment showed approxi-
mately 5% increase over the Mylar control in photosynthetic rates. Plants
III-ll :
-------
such as tomato, rye, peanut, and digitgrass did not show any pronounced
net photosyntheticreductions. However, in a growth chamber having the
same UV-B enrichment but a lower PAR, all seven species (pea, bean, tomato,
collard, cabbage, corn, and oat) showed apparent reduction in net photo-
synthesis under the UV-B enhanced treatment. Greenhouse-grown plants of
Pi sum sativum, after 4 hrs of exposure to UV-B irradiation, also showed
significant depression in photosynthetic rates (Brandle ejt a_l_., 1977).
In Rumex patientia, hourly photosynthetic determinations over a one-day
period showed that significant reduction of photosynthesis was detected
after only 2 hrs of exposing 5-week old plants to the UV-B irradiance
(Sisson and Caldwell, 1976). After 7 hrs of UV treatment, the photosyn-
thetic rates of the UV-radiation-treated plants were depressed 15% below
the control plants.
Results from studies with effects of UV-B enhanced regime on plants
by Van et al. (1976) indicated that in their greenhouse experiments, all
plants possessing the C3 pathways of carbon assimilation showed pronounced
reductions in net photosynthetic rates. Plants having the Cซ pathways
(such as corn, pearl millet, digitgrass, and sorghum) did not exhibit any
significant reduction in net photosynthesis. In their growth chamber-
grown plants, all -plants tested, whether C3 or C., showed significantly
reduced C02 uptake rates. Those differential responses to UV-B enhancement
of C. plants in greenhouse and growth chamber experiments were attributed
to low levels of visible light in growth chambers, resulting in less effi-
cient degree of photorepair mechanisms for plants in a growth chamber as
compared to those grown in a greenhouse. It had been suggested that photo-
repair is an important mechanism for protection of alpine vegetation against
111-12
-------
solar UV radiation (Caldwell, 1968). Also soybean and Rumex patientia,
when exposed to low levels of visible light and enhanced UV-B radiation,
showed more pronounced damage than when plants were under the same dose
of UV-B and higher PAR (Sisson e_t aJL, 1974). In our greenhouse experi-
ments, UV-B treatment at 2.25 UV-B did show significant depressions of
net photosynthesis in sweet corn (Table 6); this effect was also probably
partly due to the low level of PAR in this treatment that plants received
during the growth period. The possible stimulation of sweet corn net
photosynthetic rates at low doses of UV-B radiation either by the UV-B
spectrum or by other specific wavelengths emitted by the sun lamp that
are responsible for this enhancement cannot be determined or explained.
(3) Hill activity
Hill reaction activities of chloroplast preparations from leaves of
control plants and plants irradiated with a UV-B enhancement regime were
measured for comparative purposes of the photoreducing capacity of these
chloroplasts. The results of these measurements -are shown in Table 7 for
'Bragg1 soybean and in Table 8 for 'Rutgers' tomatoes. In soybean, the
Hill activity in chloroplasts from plants exposed to 2.25 and 1.64 Uv-B$eu
were significantly reduced as compared to the controls, with inhibition as
high as 40% with respect to the control being observed with plants receiving
highest doses of UV treatment. In tomatoes, Hill activity was-reduced 30%
in plants treated with 2.25 UV-B . No significant inhibitions were observed
in treatments of 1.64 and 1.31 UV-B . In both plant species, Hill reaction
activities were similar among the control plants. No effect on photore-
duction of the dye DCPIP was detected in plants irradiated with 1.31 UV-B .
UV-C has been reported to inhibit Hill reaction and photophosphorylation
111-13
-------
in chloroplast preparations of several plant species .(Holt e_t al_., 1951;
Shavit and Avron, 1963; Jones and Kok, 1966; Mantai and Bishop, 1967).
Early studies by Holt crt aK (1951) with Scenedesmus showed that Hill acti-
vity of chloroplast fragments isolated from these green algae was reduced
with exposure to 253.7 nm radiation. Similar results were obtained later
by Mantai and Bishop (1967) with chloroplasts prepared from this species.
Chloroplast preparations from higher plants such as spinach and Swiss
chard were also decreased in Hill activity following an exposure to UV-C
irradiation (Bishop, 1959; Shavit and Avron, 1963; Jones and Kok, 1966).
Relatively few data have been reported concerning the effects of UV-B
on Hill activity and other component reactions of photosynthesis. Studies
on chloroplasts isolated from leaves of 'Early Alaska1 pea seedlings grown
under field conditions with supplemental UV-B radiation showed no significant
effects in Hill reaction (Brandle, 1975). However, when 'Little Marvel1 peas
and 'Flat Dutch1 .cabbage were grown in growth chambers with enhanced UV-B
that simulated a 50% atmospheric ozone depletion, significant inhibition
(18%) in the Hill reaction was observed (Thai, 1975). When 'Little Marvel1
peas, collard, and peanut were grown under natural greenhouse conditions
and chloroplast preparations of these species were irradiated with 298 nm
monochromatic, radiation, progressive inhibitions in both Hill activity and
photophosphorylation were observed with increasing exposure to the radiation.
After 2 min of irradiation, Hill activity was inhibited 20% in pea and collard,
and 30% in peanut; this inhibition reached 50% after 4 min in all three species.
After 10 min of irradiation, inhibition in Hill activity averaged 94% for
pea and collard, and 97% for peanut which has been classified as a 'tolerant'
crop in respect to UV-B irradiation (Thai, 1975).
.111-14
-------
I At the present time, no clear conclusions have been made on the
mechanism or site(s) of inhibition by UV radiation. It has been suggested
that UV-C and UV-B radiation would have the same overall effect and share
a common mechanism or site(s) with respect to biological activity (Garrard
and Brandle, 1975), and that inhibition by UV-B radiation was more closely
associated with Photosystem II than with Photosystem I (Brandle et al.,
1977). Disruptions of the structural integrity of chloroplast lamellar
membranes resulting from exposure of plants to UV-B radiation (Section V)
are contributing factors in a decrease in Photosystem II activity and its
associated reactions (Mantai frt a]_., 1970; Brandle et. aJL, 1977) and depres-
sions in photosynthesis.
LITERATURE CITED
1) Arnold, W.A. 1933. The effect of ultraviolet light on photosynthesis.
J. Gen. Physiol. 17:135-143.
2) Arnon, D.I. 1949. Copper enzymes in isolated chloroplasts. Poly-
phenol oxidase in Beta_ yjj^garis. Plant Physiol. 24:1=15.
3) Basiouny, F-M- and R.H. Biggs. 1975. Photosynthetic and carbonic
anhydrase (CA) activities in Zn-deficient peaches exposed to UV-B
radiation. In: Climatic Impact Assessment Program (CIAP), U.S.
Department of Transportation, Monograph 5, Part 1, 4-75 to 4-80.
111-15
-------
4) Bishop, N.I. 1959. The activity of a naturally occurring quinone
(Q-225) in photochemical reactions of isolated chloroplasts. Proc.
Natl. Acad. Sci. U.S. 45:1696-1702.
5) Bowes, G., W.L. Ogren, and R.H. Hageman. 1972. Light saturation,
photosynthesis rate, RuDP carboxylase activity, and specific leaf
weight in soybeans grown under different light intensities. Crop
Sci. 12:77-79.
6) Brandle, J.R. 1975. Responses of the photochemical apparatus of
chloroplast to elevated UV-B irradiance under field conditions. In:
Climatic Impact Assessment Program (CIAP), U.S. Department of Trans-
portation, Monograph 5, Part 1, 4-149 to 4-153.
7) Brandle, J.R., W.F. Campbell, W.B. Sisson, and M.M. Caldwell. 1977.
Net photosynthesis, electron transport capacity, and ultrastructure
of Pi sum sativum L. exposed to ultraviolet-B radiation. Plant
Physiol. 60:165-169.
8) Caldwell, M.M. 1968. Solar ultraviolet radiation as an ecological
factor for alpine plants. Ecol.Mdnogr. 38:243-267.
9) Caldwell, M.M. 1977. The effect of solar UV-B radiation (280-315 nm)
on higher plants: Implications of stratospheric ozone reduction. In:
Research in Photbbiology, A. Castellani, ed., Plenum Press, New York,
pp. 597-607.
111-16
-------
10) El-Mansy, H.I. and F.B. Salisbury. 1971. Biochemical responses of
Xanthium leaves to ultraviolet radiation. Rad. Bot. 11:325-328.
11) El-Mansy, H.I. and F.B. Salisbury. 1974. Physiological responses of
onion plants to UV irradiation at 0ฐC. Rad. Bot. 14:51-57.
12) Garrard, L.A. and J.R. Brandle. 1975. Effect of UV radiation on
component processes of photosynthesis. In: Climatic Impact Assess-
ment Program (CIAP), U.S. Department of Transportation, Monograph 5,
Part 1, 4-20 to 4-32.
13) Green, A.E.S., T. Sawada, and E.P. Shettle. 1974. The middle ultra-
violet reaching the ground. Photochem. Photobiol. 19:251-259.
14) Hendricks, S.B. 1967. Light in plant life. In: Harvesting the Sun-
Photosynthesis in Plant Life, A.S. Pietro, F.A. Greer, and T.J.Army, eds,
Academic Press, Inc., New York, pp. 1-14.
15) Hesketh, J.D. 1968. Effects of light and temperature during plant
growth on subsequent leaf CO^ assimilation rates under standard condi-
tions. Aust, J. Biol. Sci. 2:235-241.
16) Holt, A.S., I.A. Brooks, and W.A. Arnold. 1951. Some effects of 2537
o
A on green algae and chloroplast preparations. J. Gen. Physiol.
34:627-645.
111-17
-------
I
17) Jones, L.W. and B. Kok. 1966. Photoinhibition of chloroplast reac-
tions. II. Multiple effects. Plant Physiol. 41:1044-1049.
18) Liaaen-Jensen, S. and A. Jensen. 1971. Quantitative determination
of carotenoids in photosynthetic tissue. In: Methods in Enzymo-
logy, Vol..23, A,S. Pietro, ed.. Academic Press, Inc., New York,
pp. 586-602.
19) Mantai, K.E. and N.I. Bishop. 1967. Studies on the effects of ultra-
violet irradiation on photosynthesis and on the 520 nm light-dark
difference spectra in green algae and isolated chloroplasts. Biochim.
Biophys. Acta 131:350-356.
20) Mantai, K.E., J. Wong, and N.I. Bishop. 1970. Comparison studies .of
the effects of ultraviolet irradiation on photosynthesis. Biochim.
Biophys. Acta 197:257-266.
21) Mbaku, S.B. 1976. Photosynthetic carbon dioxide fixation and carbo-
hydrate metabolism in isolated leaf cells of the C. tropical pasture
grass slenderstem digitgrass, Digitaria pentzii Stent.Ph.D. Disserta-
tion, University of Florida, pp. 135.
22) Monties, B. 1974. Rayonnement ultraviolet et photosynthese. In:
.Photosynthese et production vegetale, C. Costes, ed., Gauthier-Vil-
lars, Paris, pp. 193-215.
111-18
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23) Shavit, N. and M. Avron. 1963. The effect of ultraviolet light on
photophosphorylation and the Hill reaction. Biochim. Biophys. Acta
66:187-195.
24) Sisson, W.B. and M.M. Caldwell. 1976. Photosynthesis, dark respi-
ration, and growth of Rumex patientia L. exposed to ultraviolet irra-
diance (288 to 315 nanometers) simulating a reduced atmospheric ozone
column. Plant Physiol. 58:563-568.
25) Sisson, W.B., W.F. Campbell, and M.M. Caldwell. 1974. Photosynthetic
and ultrastructural responses of selected plant species to an enhanced
UV (280 - 320 nm) irradiation regime. Amer. Soc. Agron. Abs., p. 76
26) Skokut, T.A. J.H. Wu, and R.S. Daniel. 1977. Retardation of ultra-
violet light accelerated chlorosis by visible light or by benzylade--
nine in Nicotiana glutinosa leaves: Changes in amino acid content and
chloroplast ultrastructure. Photochem. Photobiol. 25:109-118.
27) Starnes, W.J. and H.H. Hadley. 1965. Chlorophyll content of various
strains of soybeans, Glycine max (L.) Merrill. Crop Sci. 5:9-11.
28) Tanada, T. and S.B. Hendricks. 1953. Photoreversal of ultraviolet
effects in soybean leaves. Amer. J. Bot. 40:634-637.
29) Thai, V.K. 1975. Effects of solar ultraviolet radiation on photosynthesis
of higher plants. Ph.D. Dissertation, University of Florida, pp. 84.
111-19
-------
30) Van, T.K., L.A. Garrard, and S.H. West. 1976. Effects of UV-B
radiation on net photosynthesis of some crop plants. Crop Sci.
16:715-718.
31) Wolf, D.D., R.B. Pearce, G.E. Carlson, and D.R. Lee. 1969. Mea-
suring photosynthesis of attached leaves with air-sealed chambers
Crop Sci. 9:24-29.
32) Wu, J.H., T. Skokut, and M. Hartman. 1973. Ultraviolet-radiatton-
accelerated leaf chlorosis: Prevention of chlorosis by removal of the
epidermis of by floating leaf discs on water. Photochem. Photobiol.
18:71-77.
111-20
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TABLE 1
EFFECT OF UV-B RADIATION ON CHLOROPHYLL CONTENT-/
Species-/ Treatment-/ Chi. (a + b)-/ Chi, a Chi, b a/b
'Bragg' soybean Mylar control 3.48 (100) ** a 2.70 (100) 0.78 (100) 3.46
1.64 (T2) 2.61 (75) b 2.01 (74) 0.60 (77) 3.35
2.25 (T3) 2.25 (65) c 1.69 (63) 0.55 (71) 3.07
'Altona' soybean Mylar control 3.83 (100) * a 2.97 (100) 0.86 (100) 3.45 .
1.64 (T2) 3.00 (78) b 2.35 (79) 0.66 (77) 3.56
2.25 (T3) 3.03 (79) b 2.33 (73) 0.70 (81) 3.33
'Little Marvel1 Mylar control 2.06 (100) ** a . 1.53(100) 0.53(100) 2.89
peas
J.64 (T2) 1.71 (83) b 1.32(86) 0.40(75) 3.30
2.25 (T3) 1.65 (80) b 1.23 (80) 0.41 (77) ' 3.00
/ Chlorophyll in mg g fresh weight. Values in parenthesis are percentages with respect to Mylar controls.
-/ -Planted - May 6, 1977; analyzed - June 1, 1977
/ UV-B enhancement in sun equivalent units (uv~Bseu)- Duration of UV-B exposure was 200 hrs.
-/ Values with different letters in the same column are significantly different at the 0.05 level (*) or
0.01 level (**) in a Duncan Multiple Range Test, each cultivar considered separately.
-------
TABLE 2
EFFECT OF UV-B RADIATION ON CAROTENOID CONTENT-'
I/
Species-
1 Bragg1
soybean
'Altona'
soybean
Total carotenoid-
% of control
'Little
Marvel pea
Treatment-/
Mylar control
1.64 (T2)
2.25 (T3)
Mylar control
1.64 (T2)
2.25 (T3)
Mylar control
1.64 (T2)
2.25 (T3)
- Carotenoid in mg g fresh weight
-/ Planted * May 6, 1977; analyzed - June 1, 1977
- UV-B enhancement in sun equivalent units (uv~Bseu)- Duration of UV-B
exposure was 200 hrs.
Values with different letters in the same column are significantly
different at the 0.05 level (*) or 0.01 (**) level in a Duncan Multiple
Range Test, each cultivar considered separately.
0.638
0.475
0.426
0.644
0.574
0.566
0.349
0.302
0.313
* a
b
c
* a
b
b
**a
b
b
100
74
67
100
89
88
100
87
90
-------
TABLE 3 ;
EFFECT OF UV-B RADIATION ON NET PHOTOSYNTHESIS IN SOYBEANS-/
Plant-/
'Bragg1
soybean
'Altona1
soybean
2/
Treatment-
Mylar control
1.64 (T2)
2.25 (T3)
Mylar control
1.64 (T2)
2.25 (T3)
3/
Net photosynthesis
(mg C02 dm" hr" )
25.0
23.3 n.s.
21.5 n.s.
29.2 * a
22.0 b
26.6 ab
% of control
100
93
86
100
75
91
Planted - May 6, 1977; analyzed - June 14-16, 1977.
- UV-B enhancement in sun equivalent units (uv~Bseu)- Duration of UV-B
exposure was 230 hrs.
3/ -2 -1
Photosynthesis was measured at 1400 yE m sec
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test, each
cultivar considered separately.
n
-------
TABLE 4
EFFECT OF UV-B RADIATION ON NET PHOTOSYNTHESIS OF 'BRAGG' SOYBEAN-/
Treatment- Net photosynthesis- % of no UV control
(mg C02 dm hr'1)
No UV control 5.79 * a 100
Mylar control for ^ 5.22 ab 90
Mylar control for T,, 4.94 b 85
1.31 (T^ 4.94 b 85
1.64 (T2) 3.02 c 52
2.25 (T3) 4.16 d 72
I/ Planted - June 20, 1977; analyzed - August 22-24, 1977.
- Duration of UV-B exposure was 210 hrs. UV-B enhancement in sun equivalent
units (uv~Bseu)- No UV control was set up also in greenhouse without any
supplemental filtered UV lamps. In Mylar control for T, and T^, the distances
between plant apical buds and Mylar filtered lamps were adjusted similarly
as for treatments T, and T-, respectively.
3/ -2 -1
Photosynthesis was measured at 700 yE m sec
*
Values with different letters in the same column are significantly different
at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 5 ?
EFFECT OF UV-B RADIATION ON NET PHOTOSYNTHESIS OF 'RUTGERS1 TOMATOES
2/ 3/
Treatment- Net photosynthesis- % of no UV control
No UV control
Mylar control for T,
Mylar control for T3
1.31 (T,)
1.64 (T2)
2.25 (T3)
Planted - July 20, 1977; analyzed - August 30-31, 1977
2/ Duration of UV-B exposure was 250 hrs. UV-B enhancement in sun equivalent
units (UV-Bseu).
3/ -2 -1
- Photosynthesis was measured at 700 yE m sec '
Values with different letters in the same column are significantly different
at the 0.05 level in a Duncan Multiple Range Test.
(mg
C02 dm"2 1
5.61 *
5.58
5.08
4.65
4.13
3.77
ir~ )
a
a
ab
be
cd
d
100
99
91
83
74
67
-------
TABLE 6
EFFECT OF UV-B RADIATION ON NET PHOTOSYNTHESIS OF SWEET CORN-/
2/ 3/
Treatment- Net photosynthesis- % of no UV control
(mg C02 dm"2 hr"1)
No UV control 55.59 * ab 100
Mylar control for T2 53.88 be 97
1.31 (T^ 59.71 a 107
1.64 (T2) 55.71 ab 100
2.25 (T3) 49.79 c 89
-' Planted - October 4, 1977; analyzed - November, 7-8, 1977
21
- Duration of UV-B exposure was 210 hrs. UV-B enhancement in sun equivalent
units (UV-Bseu).
3/ "2 -1
- Photosynthesis was measured at 700 yE m sec
Values with different letters in .the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 7
EFFECT OF UV-B RADIATION ON PHOTOREDUCTION OF DCPIP OF CHLOROPLAST PREPARATIONS
FROM 'BRAGG1 SOYBEAN LEAVES-/
Treatment-/ Hill activity-/ % of no UV control
No UV control
Mylar control for T,
Mylar control for T3
1.31 (Tj)
1.64 (T2)
2.25 (T3)
-/ Planted - July 20, 1977; analyzed - September 2, 1977.
2/
- Duration of UV-B exposure was 260 hrs. UV-B enhancement in sun equivalent
units (UV-Bseu)
57 _2 -1
- PAR irradiance was 800 yE m sec at the surface of the reactant.
DCPIP: 2,6-dichlorophenolindophenol .
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
(ymoles
OCPIP red.
238.9
229.9
241.5
238.2
194.5
141.9
rag"1 chl hr"1)
* a
ab
a
a
b
c
100
96
101
100
81
59
-------
TABLE 8 ;: .
EFFECT.OF UV-B RADIATION ON PHOTOREDUCTION OF DCPIP OF CHLOROPLAST PREPARATIONS
FROM 'RUTGERS' TOMATO LEAVES-/
Treatment-/ Hill activity-/ % of no UV control
No UV control
Mylar control for T,
Mylar control for T~
1.31 (Tj)
1.64 (T2)
2.25 (T3)
IP red. mg
172.0 **
174.6
173.0
176.5
163,0
120.2
chl hr"1)
a
a
a
a
a
b
100
102
101
103
95
70
I/
Planted - July 20, 1977; analyzed - September 6, 1977.
2/
Duration of UV-B exposure was 280 hrs. UV-B enhancement in sun equivalent
units (UV-Bseu).
o/ _o -I
-' PAR irradiance was 800 pE m sec at the surface of the reactant.
Values with different letters in the same column are significantly different
at the 0.01 level in a Duncan Multiple Range Test.
-------
An
665
2,0
1,5
1,0
,7
,3
,1
\
\
Axn
Figure 1. [^555] vs. wavelength of 80% acetone leaf pig
ment extract of 'Bragg' soybean. The extract
was scanned from 710 nm to 330 nm, the
absorbance value at 665 nm was taken as
unity and the absorbance values at other
wavelengths were expressed relative to it.
C: Mylar'control, T0 (1.64 UV-B ), T
(2.25 UV-Bseu.)
seu'
330 350
400 450 585 600
Wavelength (nm)
665
-------
n
-65
1,0
,7
,3
,1
330 350
Figure 2.
A
665
vs. wavelength of 80% acetone leaf
pigment extract of 'Altona' soybean.
Calculations and explanations same as in
Fig. 1. C: Mylar control, T0 (1.64 ..-.
UV-BCQ1I), T, (2.25 UY-15 ,) 2
seu
seu'
400 450 585 600
Wavelength (nm)
650 665
-------
An
665
2,0
T
T
1,5
1,0
,7
,3
,1
Figure 3.
Axn
A
665
vs. wavelength of 80% acetone leaf
pigment extract of 'Little Marvel1 pea.
Calculations and explanations same as in
Fig. 1. C: Mylar control, T9 (1.64
(2.25 UV-B_) 2
seu'
seu'
330 350
400 450 585 600
Wavelength (nm)
650 665
-------
SECTION IV
EFFECTS OF SUPPLEMENTAL UV-B RADIATION ON PRIMARY CARBOXYLATING
ENZYMES AND SOLUBLE PROTEINS IN C3 and C4 AGRONOMIC CROPS
INTRODUCTION
Basic responses to enhanced UV-B radiation such as inhibitions of
photosynthesis, growth, and biomass accumulation have been reported (e.g.,
Van et_al_., 1976; Sisson and Caldwell, 1976; Brandle e_t^ al_., 1977).
Less in-depth information is available on the effects of UV-B radiation
on different physiological and biochemical processes (Garrard and Brandle,
1975). UV-B radiation is readily absorbed by nucleic acid and protein
chromophores. Their involvement in plant responses to UV radiation has
been documented (Caldwell, 1971; Murphy, 1975; Giese, 1976). The involve-
ment of these components in biological responses 'to UV radiation would in-
dicate that protein synthesis and enzyme activities could be affected if
biological systems were exposed to UV-B radiation (Garrard and Brandle,
1975). RuDP-carboxylase and PEP-carboxylase are two important enzymes
involved primarily in the carbon fixation cycle in C^ and Cซ plants,
respectively. Depression of COo uptake rates in leaves of plants exposed
to UV-B radiation (Section III) would suggest the possibility of an effect
of this ultraviolet radiation on these enzymes.
In this section, results were reported on investigations of the ef-
fects of UV-B radiation on RuDP-carboxylase in soybean and tomato (C^
plants) and PEP-carboxylase in sweet corn (C. plant). Studies included
determination of the enzyme activities and the amounts of soluble proteins
extracted from leaves of plants which had been exposed to different doses
of UV-B radiation throughout their life cycles.
IV-1
-------
MATERIALS AND METHODS .
(1) Extracts and Assays of Ribulose-1 ;5-diphcsphate carboxylase (RuDP-
Case) and Phosphoenolpyruvate Carboxylase (PEP-Case)
! Experiments on RuDP-Case were performed on leaves of 4-week old
'Bragg1 soybeans and 8-week old 'Rutgers1 tomatoes. PEP-Case was iso-
lated from 4-week old sweet corn. Crude extracts from whole leaves
were prepared and enzyme activities were assayed by measuring the
14
rates of COo incorporation into acid-stable products by a modification
of a method described by Bowes and Ogren (1972) and Mbaku (1976).
Leaves that were used for experiments were the top 3rd and 4th trifo-
liates (soybeans), or the top 4th and 5th multifoliate (tomatoes). For
sweet corn, the 2nd and 3rd fully developed leaves from the top were
used. Approximately 0.8 g of fresh weight leaf samples, with midribs
removed, were homogenized with a prechilled mortar and pestle in 5 ml of
ice-cold 50 mM Tris (pH 8.0) containing 10 mM MgCU, 0.1 mM EDTA-Na2,
5 mM D-isoascorbate, and 5 mM dithiothreitol (DTT). The homogenate was
spun in a Sorvall RC-2 automatic refrigerated centrifuge at 35,000 g for
15 min and the resultant supernatant was kept in ice bath and used for
enzyme activity assays.
For assay of RuDP-Case, the incubation mixture of 2 ml contained 50
mM Tris pH 8.0, 10 mM MgClr,, 0.1 mM EDTA-Na2> 0.4 mM ribulose-1,5-diphos-
phate, 5 mM DTT, and 10 mM NaH14C03 (0.25 yCi/ymole). For PEP-Case
assay, 2 ml of incubation mixture contained 50 mM Tris pH 8.0, 10 mM
MgCl , 0.1 mM EDTA-Na^, 5 mM Na-glutamate, 2 mM phosphoenolpyruvate, and
5 mM NaH C03 (0.5 yCi/ymole). The reaction mixtures were placed in'pyrex
test tubes, sealed with serum caps, flushed with N2 for 2 min, and gently
IV-2
-------
shaken in a water bath at 32ฐC for 3 min. Aliquot of 0.2 ml of crude
enzyme extract was then injected through the serum cap into the mixture
to initiate the reaction. After 3 min at 32ฐC, the reaction was
stopped by injecting 0.2 ml of 6N glacial acetic acid. Unreacted COp
was removed by flushing the reaction mixtures with N~ for 3 min. Aliquots
of 0.3 ml were placed into scintillation vials and 10 ml of scintillation
fluid added that was composed of 100 g napthalene, 7 g 2,5-diphenyloxa-
zole (PPO), and 0.3 g 1,4-bis-2-(5-phenyloxazolyl )-benzene (POPOP) in .1
1 of 1,4-dioxane. Contents were stirred vigorously with Vortex mixer and
samples were counted in a Packard Tri-^Carb Liquid Scintillation spectro-
meter, Model B 2450.
(2) Determination of Soluble Proteins
Soluble proteins in the cell free enzyme extracts were determined by
mixing an aliquot of the extract with an equal volume of cold 10% tri-
chloroacetic acid (TCA). The mixtures were shaken and incubated in an
ice bath for about 1 hr for complete precipitation of proteins. The pro-
tein pellets were sedimented and collected by centrifugation at 2000 g for
15 min and were redissolved in 0.1 N NaOH. Colorimetric determination of
the protein was based on the method of Lowry e_t al_. (1951). Freshly pre-
pared solutions of crystalline bovine albumin was used as standards.
RESULTS AND DISCUSSION
(1) RuDP-Carbokylase in soybeans and tomatoes
RuDP-carboxylase (D-RuDP-Case) has attracted considerable attention
as an enzyme unique to the Calvin cycle (Krogman, 1973). In green plants,
the enzyme is found inside the chloroplast, sometimes in crystalline form,
IV-3
-------
and is probably the most abundant protein on earth (Wildman e_t aJL, 1975;
i
Baker ejt ajL, 1977). The in vitro activity of isolated RuDP-Case in highly pu-
rified crystalline form could be close to that of the enzyme which per-
forms the process of carbon dioxide fixation in vivo (Babajonova et al.,
1977). Since the enzyme comprises up to 50% of the soluble protein in
green leaves (kawashirna and Wildman, 1970), high activity has been re-
ported even when studies were conducted with crude extracts (Bowes et al.,
1972; Mbaku, 1976). In this experiment, crude extracts of RuDP-carboxy-
lase from leaves of control and UV-B treated plants of 'Bragg' soybean
and 'Rutgers' tomato were assayed for their capabilities of incorporation
of C02 into acid stable products.
In soybean all three UV-B doses significantly reduced the activity
of the enzyme when it was expressed on the basis of fresh weight (Table 1).
Surprisingly, the greatest depression was found in plants that had been
exposed to 1.64 uv-Bseu (treatment T,,), with approximately 60% inhibition
relative to the no UV control. The degree of inhibition decreased to 46%
and 28% relative to the no UV control for treatments of 2.25 and 1.31 UV-Bseu,
respectively. Statistical analyses showed significant differences in
enzyme activity among the three UV treatments. Some differences, although
not statistically significant, were also.,noted among the controls. when
enzyme activity was expressed on a protein basis, a similar pattern of en-
zyme inhibition by UV-B was observed, with the greatest inhibition in C02
incorporation being found in the 1.64 UV-B (To) treatment (Table 2).
seu ^
The inhibitions were 44%, 26%, and 20% with respect to the no UV control
for the treatment T2 (1.64 UV-Bseu), T3 (2.25 UV-B$eu), and TI (1.31
(UV-Bseu), respectively.
IV-4
-------
In tomatoes, enzyme inhibitions by UV-B were similar, although
smaller, compared to those in soybeans. Crude enzyme extracts from toma-
to leaves exposed to 1.64 UV-B also showed the lowest activity when
expressed either on a fresh weight basis (Table 3) or on a protein basis
(Table 4). Highest RuDP-Case activity was found in the Mylar control for
treatment T3 (Tables 3 and 4), and this activity, when expressed on a
protein basis, was significantly different from two other controls (Table
4).
Attempts were made to correlate RuDP-carboxylase activity with photo-
synthetic rates of both soybeans and tomatoes under UV-B treatment. There
is evidence that indicates that differences in leaf CCL uptake rates can
be accounted for by differences in RuDP-carboxylase activity (Bjorkman,
1968). Thus, the activity of carboxylase may be a good means of esti-
mating the photosynthesis rates in plants. In Phaseolus vulqaris, in-
creased photosynthetic rates have been attributed to an increase in car-
boxylase activity (Wareing ejt aj_., 1968). Also, in growth chamber-grown
soybeans, a good correlation between the activity of this enzyme and photo-
synthesis was reported (Bowes e_t al_., 1972). By comparing the results of
net photosynthetic measurements (Tables 4 and 5, Section III) to those of
RuDP-carboxylase (Tables 1-4), some close relationships between the enzyme
activity and net photosynthetic capacity were observed. 'Bragg' soybean
plants exposed to 1.64 UV-B had the lowest calue of photosynthesis and
enzyme activity. In other UV treatments and controls, changes in enzyme
activity and photosynthetic capacity were found to be roughly parallel.
In tomatoes, although net photosynthesis was found to be lowest in 2.25
UV-B treatment, the photosynthetic values at this UV dose was not
IV-5
-------
statistically different from those plants exposed to 1.64 UV-B . In
the other treatments and controls, tomato plants also showed some correla-
tion between leaf CCL uptake and carboxylase activity.
1 RuDP-carboxylase catalyzes the reaction of CCL with ribulose 1,5-di-
phosphate (RuDP) and is probably the enzyme responsible for the bulk of
COp fixation in most green plants. Little information and work have
documented the effects of ultraviolet radiation on this important carbo-
xylating enzyme. Preliminary studies by Thai (1975) showed no reduction
in activity of RuDP-carboxylase which was extracted from leaves of growth
chamber-grown pea and cabbage plants that had been exposed for 200 hrs
and 300 hrs, respectively, to UV-B enhancement that simulated a 50%
atmospheric ozone depletion. However, when crude enzyme preparations from
pea, collard, and peanut were irradiated with 298 nm monochromatic radia-
4 -2
tion at a high intensity dose (1.92 x 10 J m ), inhibitions in enzyme
activity of about 30% in pea and 20% in collard and peanut were observed.
Also in tomatoes, there was approximately 20% of decrease in RuDP-carbo-
xylase activity when extract from leaves was irradiated for 2 min with 296
nm monochromatic radiation (Thai, 1975).
(2) PEP-carboxylase in sweet corn
The photosynthetic carbon fixation pathway in C^ plant differs from
the conventional Calvin cycle (Hatch and Slack, 1970). C. plants utilize
PEP-carboxylase for the initial photosynthetic carboxylation before carbon
can continue its flow through RuDP-carboxylase to carbohydrates. Crude
extracts from leaves of C. species showed that the activity of PEP-carbo-
xylase was several times higher than that of RuDP-carboxylase (about'14-
fold higher in corn on a protein basis, Bowes et, aj_., 1972, and 40-fold
IV-6
-------
higher in slenderstem ch'gitgrass on a chlorophyll basis, Mbaku, 1976).
Therefore, from a biochemical and physiological point of view, studies
of PEP-carboxylase are worthwhile and might help to explain why C. plants
generally seem to be more 'resistant1 to UV-B radiation than C3 plants.
The effects of UV-B radiation on C(L incorporation by PEP-carboxylase
in crude extracts from sweet''corn leaves were presented in Tables 5 and
6. The activity of the enzyme was significantly suppressed with respect
to the no UV control when plants were exposed to UV-B radiation at the two
highest doses, 2.25 UV-BC&|| (T,) and 1.64 UV-BCOI1 (T9). The differences
ocu 0 ocw ฃ
in PEP-carboxylase were greater when expressed on a fresh weight basis
(Table 5) than on a protein basis (Table 6). Plants exposed to 1.31 UV-B
(T,) had highest enzyme activities and also had highest values of photo-
synthetic rates (Table 6, Section III). For some unknown reasons, plants
growing under the Mylar control were significantly lowest in enzyme acti-
vity on fresh weight basis (Table 5); the enzyme activity per unit protein
was also low and consequently so was the photosynthetic rate. In general,
data of PEP-carboxylase (Tables 5 and 6) and photosynthetic capacity
(Table 6, Section III) indicated that corn plants (Cซ species) were more
'resistant' to UV-B radiation than soybeans and tomatoes (C3 species).
(3) Soluble proteins
Since RuDP-carboxylase, and possibly PEP-carboxylase, can be expected
to account for a large fraction of the total leaf protein, a substantial
part of the difference in protein content among UV-B treated and control
plants may be attributed to the different levels of this enzyme. Tables
7, 8, and 9 show the protein content in leaves of plants that had been
exposed to different doses of UV-B enhancement. In 'Bragg1 soybeans, UV-B
IV-7
-------
caused a significant decrease in soluble proteins as compared to those
of the control plants (Table 7). Inhibitions with respect to the no UV
control, were 25% at the high (2.25 UV-Bseu) and medium (1.64 UV-Bseu)
dose, and 10% at the low dose (1.31 UV-Bseu). In both Mylar controls,
increases in protein content relative to the no UV control, although
not statistically different, were observed. Tomato plants behave
quite differently under UV-B radiation in terms of protein content
(Table 8). Plants exposed to UV-B radiation were higher in soluble pro-
tein contents per unit fresh weight than those of the controls; conse-
quently, these data were in contrast to the results appearing in Tables
3 and 4 for RuDP-carboxylase and those in Table 5 of Section III for
photosynthesis.
In leaves of sweet corn, only UV-B at the high dose (2.25 UV-B )
significantly reduced the soluble protein content. The low level of pro-
teins in the Mylar control was closely correlated to the lowest activity
of PEP-carboxylase as compared to other treatments and controls (Table 5).
No significant reduction in proteins was observed in other treatments.
Ultraviolet radiation in general is well recognized as an effective
agent for denaturing proteins (Giese, 1976). It has been found that
ultraviolet radiation damages cells by interfering with syntheses of
macromolecules, among which nucleic acid synthesis is the prime target
(Murphy, 1975; Giese, 1976). Synthesis of proteins may also be reduced
or stopped by high doses of UV radiation (Giese, 1976).
Higher plants have been known to be damaged when exposed to ultra-
violet irradiation. The alteration of nucleic acids by UV radiation '
would ultimately lead to changes in enzymic and structural proteins
IV-8
-------
which themselves absorb UV radiation and could therefore be directly af-
fected (McLaren and Luse,.1961). Since about 75% of proteins in green
leaves is located in the chloroplasts, leaves cannot suffer much protein
loss without harm to their photosynthetic organelles (Campbell, 1975).
In wheat leaves and cucumber cotyledons, changes in chloroplast ultra-
structure were correlated with loss in protein and photosynthetic pig-
ments. This protein loss might account for the damaged chloroplasts
observed in microscopic preparations from leaves of UV-irradiated plants
(Shaw and Manocha, 1965; Butler, 1967). In 'Bragg' soybean, continued
exposure of plants to UV-B radiation caused development of visual bronzed
areas in leaves (Section V). In addition, bronzed areas frequently showed
completely collapsed palisade regions where cells closest to the adaxial
epidermis were almost or completely collapsed and/or degraded. Electron
microscopic studies revealed that the organelles of the bronzed areas,
including nuclei, mitochondria and chloroplasts, were at various stages
of breakdown and degradation, with disruption of chloroplast being observed
as severe damage induced by UV-B radiation (Section V). This would have a
significant importance on plant growth and development since the thylakoid
membrane or grana contains essentially all the photosynthetic pigments and
.<
enzymes required for the primary light-dependent reactions; the stroma, on
the other hand, contains the enzymes of the carbon cycle. Since the photo-
synthetic activity is closely related to membrane integrity of the chloro-
plast, a disruption of this organelle as a result of UV-B radiation will
partly destroy the components required for both light and dark reactions
and thus reduce the rate of C02 fixation.
Inhibition of enzyme activity by UV radiation has been suggested to be
IV-9
-------
due to protein destruction or enzyme inactivation (McLaren and Luse, 1961;
Piras and Vallee, 1966; Giese, 1976). Since the most important biochemical
property of an enzyme is its catalytic activity, a slight alteration of
its steric configuration is sufficient to make it inactive and incapable
of combining with the substrate molecule. Since inactivation always
involves some type of molecular damage to the enzyme, its quantitative
' . >..
and qualitative appraisal would be a means of assessment of the damage.
Low doses of UV-B radiation appeared to enhance the catalytic activity
of PEP-carboxylase and photosynthesis in sweet corn, larger doses, however,
inactivate the same enzyme. This phenomenon could possibly be a case of
radiation-induced creation of an active catalytic site that did not exist
before, or a case of increased reactivity of a previously existing active site
(Arena, 1971). Obviously, more studies are required before satisfactory
answers can be obtained.
LITERATURE CITED
1) Arena, V. 1971. Ionizing radiation and life. C.V. Mosby Company,
St. Louis, pp. 543.
2) Babajanova, M.A., N.G, Doman, and N.G. Chekina. 1977. Isolation
and purification of ribulose diphosphate carboxylase preparations from
pea and bean leaves in an atmosphere of inert gases. In:' Photosynthe-
sis and Solar Energy Utilization, O.V. Zalenskii, ed., Amerind
. Publishing Co., Pvt. Ltd., New Delhi, pp. 338-343.
IV-10
-------
3) Baker, T.S., D. Eisenberg, and F. Eiserling. 1977. Ribulose biphos-
phate carboxylase: a two-layered, square-shaped molecule of symmetry
422. Science 196:293-295.
4) Bjorkman, 0. 1968. Carboxydismutase activity of shade-adapted and '
sun-adapted species of higher plants. Physiol. Plant. 21:1-10.
5) Bowes, G. and W.L. Ogren. 1972. Oxygen inhibition and other proper-
ties of soybean ribulose 1-,5-diphosphate carboxylase. J. Biol.
Chem. 247:2171-2176.
6) Bowes, G., W.L. Ogren, and R.H. Hageman. 1972. Light saturation,
photosynthesis rate, RuDP-carboxylase activity, and specific leaf
weight in soybeans grown under different light intensities. Crop
Sci. 12:77-79.
7) Brandle, J.R., W.F. Campbell, W.B. Sisson, and M.M. Caldwell. 1977.
Net photosynthesis, electron transport capacity, and ultrastructure
of Pi sum sativum L. exposed to ultraviolet-B radiation. Plant
Physiol. 60:165-169. .
8) Butler, R.D. 1967. The fine structure of senescing cotyledons of
cucumber. J. Exp. Bot. 18:535-543.
9) 'Caldwell, M.M. 1971. Solar UV irradiation and the growth and develop-
ment of higher plants. In: Photophysiology, A.C. Giese, ed.,
Academic Press, New York, Vol. 6, pp. 131-177.
IV-11
-------
10) Campbell, W.F. 1975. Ultraviolet-radiation-induced ultrastructural
; changes in mesophyll cells of soybean Glycine max.(L.) Merr.
In: Climatic Impact Assessment Program (CIAP), U.S. Department of
Transportation, Monograph 5, Part 1, pp. 4-167 to 4-176.
11) Garrard, L.A. and J.R. Brandle. 1975. Effects of UV radiation on
component processes of photosynthesis. In: Climatic Impact Assess-
ment Program (CIAP), U.S. Department of Transportation, Monograph 5,
Part 1, pp. 4-20 to 4-32.
12) Giese, A.C. 1976. Living with our sun's ultraviolet rays. Plenum
Press, New York, pp. 185.
13) Hatch, M.D. and C.R. Slack. 1970. Photosynthetic C02-fixation path-
ways. Annu. Rev. Plant Physiol. 21:141-162.
14) Kawashima, N. and S.G. Wildman. 1970. Fraction I protein. Annu.
Rev. Plant Physiol. 21:325-358.
15) Krogmann, D.W. 1973. The biochemistry of green plants. Prentice-
Hall, Inc., New Jersey, pp. 239.
16) Lowry, O.H., N.J. Rosebrough, A.L. Farr, and R.J. Randall. 1951.
. Protein measurement with Folin phenol reagent. J. Biol. Chem. 193:
265-275.
IV-12
-------
17) McLaren, A.D. and R.A. Luse. 1961. Mechanism of inactivation of
enzyme protein by ultraviolet light. Science 134:836.
18) Mbaku, S.B. 1976. Photosynthetic carbon dioxide fixation and
carbohydrate metabolism in isolated leaf cells of the C^ tropical
pasture grass slenderstem digitgrass, Digitaria pentz=ii Stent. Ph.D.
Dissertation, University of Florida, pp. 135.
19) Murphy, T.M. 1975. Effects of UV radiation on nucleic acids. In:
Climatic Impact Assessment Program (CIAP), U.S. Department of
. Transportation, Monograph 5, Part 1, pp. 3-21 to 3-44.
20) Piras, R. and B.L. Vallee. 1966. Structural changes of carboxy-
peptidase A on ultraviolet irradiation. Photochem. 5:855-860.
21) Shaw, M. and M.S. Manocha. 1965. Fine structure in detached, senescing
wheat leaves. Can. J. Bot. 43:747-755.
22) Sisson, W.B. and M.M. Caldwell. 1976. Photosynthesis, dark respira-
tion, and growth of Rumex patientia L. exposed to ultraviolet irra-
diance (288 to 315 nanometers) simulating a reduced atmospheric ozone
column. Plant Physio!. 58:563-568.
23) Thai, V.K. 1975. Effects of solar ultraviolet radiation on photo-
synthesis of higher plants. Ph.D. Dissertation, University of
Florida, pp. 84.
IV-13
-------
24) Van, T.K., L.A. Garrard, and S.H. West. 1976. Effects of UV-B radia-
tion on net photosynthesis of some crop plants. Crop Sci. 16:715-718.
25) Wareing, P.P., M.M. Khalifa, and K.J. Treharne. 1968. Rate-
limiting processes in photosynthesis at saturating light intensi-
ties. Nature 220:453-457.
26) Wildman, S.G., K. Chen, J.C. Gray, S.D. Kung, P. Kwanyuen, and
K. Sakano. 1975. Evolution of ferredoxin and fraction I protein
in the genus Nicotiana. In: Genetics and Biogenesis of Chloro-
plasts and Mitochondria, P.S. Perlman, C.W. Birky, and T.J. Byers,
eds., Ohio State University Press, Columbus, pp. 309-329.
IV-14
-------
TABLE 1
EFFECT OF UV-B RADIATION ON RATE OF 14C02 INCORPORATION BY RIBULOSE-
1,5-DI-P CARBOXYLASE IN EXTRACTS OF 'BRAGG' SOYBEAN LEAVES-/
2/
Treatment- Enzyme Activity % Incorporation
(ymoles C02 hr g fresh wt)
No UV Control 434.3 * a 100
Mylar control for T, 404.8 a 93
Mylar control for T3 393.1 a 91
1.31 (T^ 312.0 b 72
1.64 (T2) 180.8 c 42
2.25 (T3) 234.0 d
54
- Planted - July 20, 1977; analyzed - August 19, 1977.
Duration of UV-B exposure was 180 hrs. UV-B enhancement in sun
equivalent units (UV-B ).
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 2
EFFECT OF UV-B RADIATION.ON RATE OF 14C02 INCORPORATION BY RIBULOSE-
1,5-DI-P.CARBOXYLASE IN EXTRACTS OF 'BRAGG1 SOYBEAN LEAVES-/
7.1
Treatment-
No UV Control
Mylar Control for T,
Mylar Control for T_
1.31 (T,)
1.64 (T2)
2.25 (T3)
Enzyme Activity
(ymoles COp hr" mg~ protein)
27.72 * a
23.40 b
23.88 ab
22.24 b
15.52 c
20.63 b
% of Incorporation
100
84
86
80
56
74
Planted - July 20, 1977; analyzed - August 19, 1977.
Duration of UV-B exposure was 180 hrs. UV-B enhancement in sun
equivalent units (UV-Bseu).
*
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 3
EFFECT OF UV-B RADIATION ON RATE OF 14C02 INCORPORATION BY RIBULOSE-
1,5-DI-P CARBOXYLASE IN EXTRACTS OF 'RUTGERS1 TOMATO LEAVES-/
21
Treatment-
No UV Control
Mylar Control for T,
Mylar Control for T-
1.31 (T,)
1.64 (T2)
2.25 (T3)
\ Enzyme Activity
(ymoles C02 hr'1 g"1 fresh wt)
280.0 * ab
276.8 ab
281.7 a
254.2 be
222.0 d
242.6 cd
% Incorporation
100
99
101
91
79
87
Planted - July 20, 1977; analyzed - September 15, 1977.
2i
Duration of UV-B exposure was 335 hrs. UV-B enhancement in sun
equivalent units (uv~Bseu)-
Values with different letters in the same column are significantly
different at the 0.05 level in a Dunca.n Multiple Range Test.
-------
TABLE 4
EFFECT OF UV-B RADIATION ON RATE OF 14C02 INCORPORATION BY RIBULOSE-
, 1,5-DI-P CARBOXYLASE IN EXTRACTS OF 'RUTGERS1 TOMATO LEAVES-/
Treatment-'
2/
- Enzyme Activity % Incorporation
(ymoles C0~ hr mg protein)
No UV Control 16.83 * c 100
Mylar Control for TI 17.61 be 105
Mylar Control for T3 19.57 a 116
1.31 (T^ 13.06 de 78
1.64 (T2) 10.29 f 61
2.25 (T3) 12.00 e 71
Planted - July 20, 1977; analyzed - September 15, 1977.
71
-' Duration of UV-B exposure was 335 hrs. UV-B enhancement in sun
equivalent units (uv~Bseu)-
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE- 5
EFFECT OF UV-B RADIATION ON RATE OF 14C02 INCORPORATION BY
PEP CARBOXYLASE IN EXTRACTS OF SWEET CORN LEAVES-/
2/
Treatment- Enzyme Activity % Incorporation
\ 11
(.ymoles: C02 hr ' g ' fresh wt)
No UV Control 867.6 * a 100
Mylar Control for T2 653.1 b 75
1.31 (Tj) 902.8 a 104
1.64 (T2) 734.0 cd 85
2.25 (T3) 710.5 d 82
y Planted - October 4, 1977; analyzed - November 3, 1977.
Duration of UV-B exposure was 180 hrs. UV-B enhancement in sun
equivalent units (uv~Bseu).
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 6
14
EFFECT OF UV-B RADIATION ON RATE OF C02 INCORPORATION BY
PEP CARBOXYLASE IN EXTRACTS OF SWEET CORN LEAVES-/
2/
Treatment
No UV Control
Mylar Control for T2
1.31 (Tj)
1.64 (T2)
2.25 (T3)
\
\
Enzyme Activity
(nmoles C02 hr" mg protein)
76.36 * a
68.20 b
81.35 a
67.84 b
70.94 b
% Incorporation
100
89
107
89
93
- Planted - October 4, 1977; analyzed - November 3, 1977.
-' Duration of UV-B exposure was 180 hrs. UV-B enhancement in sun
equivalent units (UV-B seu).
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 7 :
EFFECT OF UV-B RADIATION ON SOLUBLE PROTEINS
OF 'BRAGG1 SOYBEAN LEAVES-/
21 3/
Treatment- Proteins- % of No UV control
(mg g fresh wt)
No UV Control 15.74 * a 100
Mylar Control for TI 17.04 a 108
Mylar Control for TS 16.41 a 104
1.31 (Tjj 14.13 ab 90
1.64 (T2) 11.74 .b 75
2.25 (T3) 11.62 b U
IS Planted - July 20, 1977; analyzed - August 19, 1977.
21
Duration of UV-B exposure was 180 hrs. UV-B enhancement in sun
equivalent units (UV-B ).
- Soluble proteins from crude enzyme extract in Tris buffer pH 8.0.
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 8
EFFECT OF UV-B RADIATION ON SOLUBLE PROTEINS
OF. 'RUTGERS1 TOMATO LEAVES-7
21
Treatment-
No UV Control
Mylar Control for T,
Mylar Control for Tg
1.31 (T,)
1.64 (T2)
2.25 (T3)
3/
Proteins-
(mg g~ fresh wt)
16.83 * cd
15.77 de
14.39 e
19.44 b
21.58 a
20.21 ab
% of No UV control
100
94
86
116
128
120
Planted - July 20, 1977; analyzed - September 15, 1977.
Duration of UV-B exposure was 335 hrs. UV-B enhancement in sun
equivalent units (uv~Bseu)-
z* Soluble proteins from crude enzyme extract in Tris buffer pH 8.0.
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
TABLE 9
i EFFECT OF UV-B RADIATION ON SOLUBLE PROTEINS OF SWEET CORN LEAVES-/
Treatment-/ Proteins--/ % of No UV Control
(mg g" fresh wt)
No UV Control 11.38 * a 100
Mylar Control for T2 9.80 b 86
1.31 (T^ 11.10 a 98
1.64 (T2) 10.83 ab 95
2.25 (T3) 10.02 b 88
-/ Planted - October 4, 1977; analyzed - November 3, 1977.
2/
Duration of UV-B exposure was 180 hrs. UV-B enhancement in sun
equivalent units (UV-Bseu)ซ '
3/
Soluble proteins from crude enzyme extract in Tris buffer pH 8.0.
Values with different letters in the same column are significantly
different at the 0.05 level in a Duncan Multiple Range Test.
-------
SECTION V
UV-B EFFECTS ON ULTRASTRUCTURE OF CROP PLANTS
INTRODUCTION
Ultraviolet enhancement (280-320 ran, or UV-B) of plant growth
regimes frequently results in an inhibition of photosynthesis. Man-
tai (1970), Mantai et al_. (1970), and Thai (1975) suggested that
the multiplicity of biological events affected by UV-B irradiation
of plant tissue may be due to a disruption in the lamellar struc-
ture of chloroplasts. Brandle et, &]_. (1977) suggested that the
decrease in net photosynthesis caused by UV-B radiation was due to
both the destruction of chloroplast lamellae and the inhibition of
electron transport at the reaction center chlorophyll of Photosy-
stem II, PS II (Okada et ^1_., 1976). Berg and Garrard (1976) found
UV-B irradiation (monochromatic, 298 nm) of haploid tobacco leaf
mesophyll tissue to cause a general alteration of chloroplast
membrane structure, including a swollen and undulating membrane
profile in the chloroplast envelope and in the grana and stromal
lamellae. In order to interpret the results of physiology
studies reported herein, an examination was made of the effect of
UV-B enhanced regimes on the structure of leaf mesophyll tissue.
MATERIALS AND METHODS '
A description of the UV-B-enhancement regime appears in Section
I of this report. In the following discussion: T represents the
\f
control tissue (grown under Mylar), T-j represents tissue grown
under a UV-B equivalent of 1.31 sun equivalent units, Tซ
V-I
-------
represents tissue grown under a UV-B equivalent of 1.64 sun equivalent
units, and T^ represents tissue grown under a UV-B equivalent of 2.25
sun equivalent units.
Both soybean (Glycine max, cv. 'Bragg') and corn (Zea mays cv.
'Golden Cross Bantam') leaf mesophyll tissue were sampled. Samples
from one-month-old plants were taken both at the beginning of the
day (to make observations on tissue depleted of starch) and the end
of the day (to observe the quantity of starch formation). With
soybean tissue, areas of leaf bronzing and yellowing occurred in cer-
tain UV-B treatments; these areas were sampled and analyzed separately.
Three soybean UV-B experiments were conducted in 1977. Tissue
samples from the third experiment were taken six weeks after emer-
gence. With corn leaves, the tissue was sampled from the central
regions of the youngest fully-expanded blade.
Tissue was fixed for electron microscopy in glutaraldehyde and
osmium tetroxide and embedded in Spurr's epoxy resin as previously
described (Berg and Garrard, 1976). Thick sections of this material
were made for light microscopy.
Citrus leaves exposed to enhanced UV-B in the field were
sampled and scanning EM, air dried over'desiccant and sputterco.ited
with gold-palladium.
RESULTS
Increased levels of UV-B irradiance caused increased areas and
degrees of chlorosis of leaves. These areas would first develop as'
vein-limited areas of whitish-yellow pigmentation (chlorosis) and, as
V-2
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jthe length of time under UV-B irradiance increased, bronzed areas
would develop within some of the chlorotic areas. Bronzing pigmenta-
tion appeared as brown-to-rust-colored areas.
1 A photographic record was made of soybean leaf development on
two-week-old plants under the various treatments. Two trifoliate
leaves per treatment were observed from emergence through 15 days
of growth. The results of these observations are presented in Table
1. .The control leaves (T ) developed normal green leaves without
any sign of chlorosis. All leaves grown under enhanced UV-B irra-
diance developed chlorosis after four days of growth. The degree
of chlorosis and the leaf area affected generally depended on the
intensity of UV-B treatment (T^T^T-j). The highest level of UV-B
irradiance caused chlorosis to occur over the longest period of
time (around seven days), and produced the greatest area and de-
gree of chlorosis. As UV-B irradiance decreased in intensity, the
duration and severity of chlorosis correspondingly decreased. . In all
cases, the leaf (and the plant) reached an age after which no further
chlorosis occurred (around three to four weeks). This was a pheno-
menon associated with the whole plant rather than on an individual
leaf basis. Most chlorosis and bronzing occurred on the plant before
this stage. There was no apparent difference in the occurrence of
chlorosis among the three leaflets comprising a trifoliate leaf. In
general, the leaflets receiving the most intense UV-B irradiance (T3)
were smaller compared to the other treatments.
A comparison of trifoliate leaves of soybean grown under
various UV-B enhancement regimes is given in Figures 1-4. The leaves
were two weeks old. Compared to the control leaf grown under Mylar
V-3
-------
(T_, Figure 2) there was a slight chlorosis in the terminal leaflet
t*
of the leaf from TI (Figure 1). There was considerably more chlorosis
in the leaf of T^ (Figure 3). This chlorosis appeared in all three
leaflets and obviously occurred in regions demarcated by vascular
tissue. The leaf shown in Figure 4 was grown under the highest
UV-B irradiance (T3). A high degree of epinasty, as well as chlorosis
and bronzing, was evident; these leaflets were smaller than those in the
more moderate UV-B treatments.
Areas of chlorosis and bronzing were delimited by vascular tis-
sue as is shown in Figures 5-7. The chlorosis in the soybean leaf of
Figure 5 was extensive, and in the more intensely chlorotic areas
bronzing occurred. Vascular tissue defines regions where there was a
sharp border between green tissue and chlorotic tissue. The close-up
photograph in Figure 6 shows the surface of a soybean leaf in a region
where bronzing occurred within chlorotic areas, both are spatially
defined by regions of vascular tissue. This is shown by the light
microscope photograph in Figure 7 that showed tissue of a region simi-
lar to Figure 6 (upper surface view). The bronzed palisade cells were
shrunk in size and were separated from green tissue by vascular tissue,
some of which contain the reddish-brown pigmentation associated with
bronzing. Limitation of chlorosis and bronzing to areas bordered by
vascular tissue indicated that these pigmentation changes (and, as will
be shown later, cell structure changes) may be associated with (and/or
be enhanced by) the production of a translocatable substance causing
lysis. Siegel and Corn (1974) found UV-C irradiation of red beet to
cause the production 'of a translocatable factor causing membrane
V-4
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lysis.
Light micrographs of transverse sections of soybean leaf meso-
phyll grown under UV-B enhancement are presented in Figures 8-10. The
control tissue in Figure 8 showed a vacuolate adaxial epidermal cell
layer subtended by several layers of palisade cells that contained
a majority of the well-developed green chloroplasts of the leaf. Be-
low the palisade layer, in the region where the vascular tissue occurs,
a vein is seen in cross-section. Subtending this region is the spongy
mesophyll tissue that also contained well-developed green chloroplasts.
This was subtended by a vacuolate layer of abaxial epidermal cells, the
tissue in Figure 9 was from a chlorotic region of soybean leaf tissue
. grown under UV-B enhancement. An abaxial trichome was present as well
as a vein in this cross-section. The most evident difference between
this tissue and the control was in the palisade layers, where there was
a substantial reduction in chloroplast volume and chlorophyll content.
This indicated that chlorosis due to UV-B irradiation was not only
restricted in the area across the leaf surface by vascular tissue, but
that it was also primarily restricted to the upper half of the leaf by
the same tissue. Areas of more severe leaf chlorosis became bronzed.
Figure 10 is a transverse section of a bronzed region. (Note that this
micrograph is presented upside down due to our printer's error). Again,
the most severe damage was located in the upper half of the leaf and'
was delimited by the vascular tissue appearing in the section shown.'
The adaxial epidermal cells were severely desiccated and the walls of
these cells gave rise to bronzing pigmentation. This pigmentation was
also located in the walls of cells in the palisade cell layer. The .
V-5
-------
palisade layer cells in bronzed regions undergo degradative changes
that result in the appearance shown in Figure 10. The cells were
desiccated, as in the adaxial epidermis, and the amount of cellular
material (especially chloroplasts) was greatly reduced. The vascular
tissue subtending the palisade layers (Figure 10) displayed a sort of
"resistance" in that the cellular structure was affected to a much
lesser extent. The phloem parenchyma contained chloroplasts. The
spongy mesophyll was likewise less affected, though the chloroplasts
in this tissue were smaller in size compared to the control tissue.
The abaxial tissue was intact and much more typical than the adaxial
epidermis.
Ultrastructure of UV-B-irradiated tissue
The fine structure of cells in leaf mesophyll tissue grown under
UV-B enhancement regimes showed distinct features, the quality of
which depended upon the pigmentation of the tissue sampled. Although
the amount of chlorosis and bronzing that occurred in UV-B-irradiated
plants increased with increasing levels of UV-B radiation, the ultra-
structure of a given type of pigmentation appeared similar, regardless
of the treatment level.
Samples from green control tissue showed the same fine structure
found in green tissue of UV-B-irradiated plants. After an overnight
period of darkness the chloroplasts were depleted in starch. Samples
taken at the end of the daylight period showed chloroplasts to form
several starch grains, as presented in Figure 11, that show green
palisade tissue from T3 (highest level of UV-B-irradiance. As in
the control tissue, this tissue appeared healthy.
Samples from chlorotic tissue showed a substantial reduction in
V-6
-------
the amount of chloroplast lamellae in palisade cells, seen in Figure
12. Most of the chloroplasts in chlorotic regions have one or two
starch grains, an amount lower than in green tissue. Spongy meso-
phyll chloroplasts from chlorotic regions contain three to five starch
grains per chloroplast. The lower levels of starch in chlorotic
palisade tissues may be due to the generally lower amount of chloro-
plast lamellae found in this tissue as well as a smaller chloroplast
volume. This was verified by light microscopy, which showed chloro-
sis to be restricted to palisade tissue (Figure 9), and the chloro-
plasts to be smaller in size. Spongy mesophyll tissue in chlorotic
regions contained green chloroplasts of normal size (Figure 9).
Organelles other than chloroplasts occurring in chlorotic regions
appeared similar in variety and appearance to those in the controls.
Chloroplasts contain ribosomes and nucleoids.
As indicated earlier, bronzing pigmentation occurred in the
walls of the adaxial epidermal cells as well as the walls of palisade
cells. The appearance of these bronzed walls on the ultrastructural
level was distinctive, as shown in Figures 13 and 14. In Figure 13
are shown two bronzed adaxial epidermal' cells subtended by a bronzed
palisade cell. The electron-dense areas in the wall were found in
regions of bronze pigmentation. The bronzing phenomenon caused
the walls to weaken, as evidenced by the collapsed wall separating
the two epidermal cells. As a result, the volume of the epidermal
cells was greatly reduced. Note that the contents of these cells
are destroyed, probably as a result of the bronzing reaction (see
section under "Lytic Cells"). Figure 14 shows the collapsed
V-7
-------
wall and degraded cytoplasm contained in bronzed epidermal cells.
Within the wall, the heaviest concentration of the electron-dense
pockets appeared in the region of the middle lamella and primary
wall. Note that the electron-dense pockets appeared to have- moved
into the cell compartment and are mixed with the remnants of the
cytoplasm, where there are no recognizable organelles. However,
remnants of membranes may be seen. In Figures 13 and 14 can be
seen the lack of any electron-dense pockets in the cuticle.
Another distinctive feature of bronzed leaf mesophyll tissue
was the quality of plastids in the palisade cells. Control tissue
contained one basic type of palisade cell whereas a variety of cell
types', based primarily on the ultrastructure of their plastids, were
found in bronzed palisade tissue. These cell types are occasionally
found in the margins of chlorotic leaf regions near the interface
between chlorotic and bronzed regions. The types are referred to
as "vesiculate", "lamellate", "alamellate", and "lytic" cell types
and will now be discussed individually.
(1) Vesiculate cells
Vesiculate cells are characterized by having plastids whose
lamellae are in various stages of vesiculation. Many of these cells
had a degree of bronzing-associated structures in their cell walls.
Figure 15 shows a typical vesiculate cell. The prominent nucleus was
bounded by an intact nuclear envelope which contained a mitochondrion
within an invagination. The several mitochondria present varied in
size from (normal) ovoid to elongate. Most mitochondria in vesiculate
cells had reduced numbers of cristae, which were somewhat vesiculated.
V-8
-------
Several dictysomes were present. Rough endoplasmic reticulum and
polysomes may be seen in the cytoplasm. The vacuole was intact and
bronzing-associated electron-opaqueness was located within some of
the cell wall.
As illustrated in Figure 15 the plastid populations of vesi-
culate cell types were generally found to contain only vesiculate-
type plastids, apparently at various developmental stages. However,
vesiculate plastids were also found in cells with mixed plastid
populations, as described in the section on "alamellate" cell types.
Vesiculate plastids are generally circular-to-ovoid in transverse
sections.
The development of the vesiculate plastid is difficult to follow,
given the fact that they occurred in bronzed regions. No clear deve-
lopmental zones occurred within bronzed regions and it is not possible
to sample a given chlorotic leaf region with the knowledge that bronzing
is about to occur therein. However, in the vesiculate type of plastid,
aberrant structures were found. This suggests that chloroplasts
(of previously green tissue) had degenerated.
The grana in vesiculate plastids contained thylakoids of a dia-
meter considerably greater than those in normal grana. These are re-
ferred to as "macrograna" (Bechmann et_ jfl_., 1969). Macrograna may be
seen in the vesiculate plastids of Figure 15. The formation of macro-
grana, rather than grana, in vesiculate plastids indicates aberrant
plastid structure.
Plastoglobuli in vesiculate plastids were generally found in the
stroma as clusters. Seen in Figure 16 is an invagination of a vesi-
culate plastid, a feature occasionally found in all plastid types
V-9
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of bronzed regions. Also seen in the plastid in Figure 16 are a
starch grain and ribosomes, both of-which are sometimes found in
vesiculate plastids. Phytoferritin was another plastid component
found in vesiculate plastids (Figures 17 and 19).
As seen in Figure 16, there was a conspicuous lack of stromal
lamellae in vesiculate plastids. Instead, vesicles were dispersed
throughout the plastid, and appeared as shortened and swollen thyla-
koids. Stacks of two shortened thylakoids, termed "thylakoid pairs",
commonly became swollen into vesicles (Figure 16) and often were more
numerous than single vesicles. Both single vesicles and thylakoid
pairs may sometimes originate from the inner membrane of the plastid
envelope (Figure 17). The degenerated plastid in Figure 17 had
a conspicuous cluster of plastoglobuli closely associated with linear
arrays of segmented lamellae apparently derived from the inner
membrane of the plastid envelope. In other cells these were found to
swell into vesicles.
Evident in Figures 18 and 19 are large vesicles derived from
dilation of thylakoids in various locations within macrograna.
Attached at the periphery of these vesicles were smaller vesicles
(perhaps derived from segmented thylakoids) separated during the
swelling of the larger vesicle. In the vesiculate plastids of
Figure 19, all of the thylakoids had some degree of swelling. In
Figure 18, the double arrows point to a region in a macrogranum
where several vesicles (and a thylakoid pair) are at one time fused
with a thylakoid. This is further evidence for an error in the
assembly of the plastid lamellar system. At the other end of this
thylakoid a thylakoid pair was attached (single arrow). The other
V-10
-------
end of the thylakoid pair adjoined the large vesicle of the adjacent
macrogranum. There was a conspicuous absence of stromal lamellae
in vesiculate plastids.
(2) Lamellate Cells
In certain palisade cells chloroplasts contained unusual stroma
lamellae (Figure 20). These lamellae were of uniform spacing in
transverse section and a relatively large proportion of these stromal
lamellae interconnect granal stacks. These plastids (and cells) may
develop into the "lamellate" cell types. As seen in Figure 21
lamellate cells contained an obviously unhealthy cytoplasm. The
nucleus in this cell (see also inset) was virtually void of contents
except for remnants of chromatin adhering to the envelope. Nuclear
pores persist. There were no ribosomes in the free form or attached
to the swollen endoplasmic reticulum (Figure 27). Dictysomes were
aberrant in structure. Both the tonoplast and plasmalemma were
ruptured and large areas of the cell were filled with vesicles
(Figure 21). The mitochondrial matrix varied in density, even-
tually becoming void of contents. Cristae were rudimentary, often
semicircular or swollen in transverse section (Figure 23). Some
of these organelles occurred in invaginations of plastids in the
lamellate cell type as in other cell types found in bronzed regions.
Bronzing-associated electron-opaque deposits were found in lamellate
cells (Figures 23-25).
The distinct plastids found in lamellate cells appeared to per-
sist compared to other organelles any may contain phytoferritin,
clusters of plastoglobuli, and an intact plastid envelope. No starch
or plastid ribosomes were found, though nucleoids may be present
V-ll
-------
;(Figure 25). Lamellate cells were so named because of the structure
of the lamellar system in their plas-tids. There were no mixed
lamellate cells, i.e., all plastids were of the lamellate type.
These plastids were generally lenticular or amoeboid in transverse
section and probably resulted from degeneration of chloroplasts.
Lamellate plastids commonly contained primary thylakoids in which
layers of thylakoids were arranged in a regular spacing in trans-
verse section (Figures 22-26). Single, irregular lamellae may also
occur in these plastids (Figure 23). In Figure 23, the primary
thylakoids appeared to adhere in forming a macrogranum. Vesicles
derived from the inner membrane of the plastid envelope were often
found in the lamellate plastid (Figures 23-25 and 27). Normal
chloroplast lamellar systems did not occur in lamellate plastids.
Degeneration in some was arrested at the primary thylakoids (Figures
22 and 24); many contained tightly appressed granum (Figures 23-27).
.In. some lamellate plastids only tightly appressed macrogranum occurred
along with single lamellae (Figure 27). In these, the formation of
macrogranum by primary thylakoids was complete. In Figure 26, pro-
jections between the regular layers of primary thylakoids may be seen.
These also occurred in regions bounded by stroma (Figure 26).
(3) Alamellate Cells
The term "alamellate cell" comes from the unique structure of
plastids in this cell type. The nuclei alamellate cells appeared
intact. Ribosomes and polyribosomes occurred in the cytoplasm and
the presence of rough endoplasmic reticulum is not uncommon. Dicty1-
somes are present. The tonoplast is intact; vesicles often appear
V-12
-------
in the vacuole, derived from the cytoplasm and invaginations of the
plasmalemma (Figure 28).. While typical mitochondria were found
(Figure 29), other of these organelles were elongated (Figure 29).
Alamellate plastids were found to have no typical thylakoids
or lamellae and appeared to result from degeneration of chloroplasts
\
(of previously green tissue). While phytoferritin occasionally
occurred (Figure 28, inset), no starch or plastid ribosomes were
found. Though not easily detected against the generally light stroma,
there was some indication of the presence of large plastid nucleiods
(Figure 31). Alamellate plastids were generally circular-to-ovoid
in transverse section. As seen in Figure 29, the lamellar system
was generally disoriented with no typical thylakoids occurring in the
plastid. However, a closer examination of Figure 29 showed the presence
of a very small "granum" (single arrow) from which "lamellae" extends
(double arrow). The transverse section showed the "lamellae" to be
entirely enclosed, as in a thylakoid. However, the matrix of this
very atypical "thylakoid" is similar in appearance to the stroma and
the nature of the other "thylakoids" in the plastid indicates they are
at least partially open to the stroma. These "lamellate" are derived
from imaginations of the inner membrane of the (intact) plastid
envelope (triple arrows). The alamellate plastid of Figure 30 con-
tains a variety of membrane configurations. Plastoglobuli are common
either as clusters or singly in alamellate plastids. There is vir-
tually no internal membrane system within the plastid of Figure 31.
The stroma is of a very low density with some indication of fibril-
lar plastid DNA being present, interspersed throughout the stroma.
V-13
-------
The vesicle within the plastid did not appear to be an invagination of
the plastid. Along with the absence of normal thylakoids in alamellate
plastids there was the occasional presence of abnormal grana. As
previously seen, these grana contained tightly appressed lamellar
membranes (Figure 29). The serial sections of Figures 32-34 transected
a semicircular granum composed of tightly appressed membranes derived
from a tubular structure that dominated the stroma. The granum
partially enclosed a myelin-like membrane structure in Figure 32.
Plastoglobuli were subsequently shown to be adjacent to the myelin
structure in later sections (Figures 33 and 34). The semi-circular
granum in Figure 35 surrounded a vesicle. The membranes comprising
the granum were continuous, and were tightly appressed in one region to
form the granum. The circular granum in Figure 36 may be a culmina-
tion of membrane appression processes that apparently occurred as
shown in Figures 32-35.
Structures only occasionally found in alamellate plastids in-
cluded the larger vesicles in Figure 37.
Alamellate plastids may also occur in cells with mixed plastid
populations. The vesiculate plastid in Figure 38 was one type found
to occur with alamellate plastids. In Figure 39 several vesiculate
plastids and chloroplasts are seen in a cell containing an alamellate
plastid. This was not termed a vesiculate cell because the two
plastid types did not appear to be developmentally related, i.e.,
purely vesiculate cells appear to have a developmental pattern that
does not include alamellate structures. The chloroplast of Figure 40
was from a cell with alamellate plastids as the sole other type of
V-14
-------
;plastid. This chloroplast was functional (has starch) and ribosomes
were present in the stroma. The alamellate plastid in Figure 30
is adjacent to a chloroplast. A chloroplast is adjacent to an ala-
mellate plastid in Figure 41. This alamellate plastid was inside
an imagination of another organelle (serial section Figure 42).
This was evidenced by the presence of cytoplasmic ribosomes between
the two organelles (Figure 41, arrow) and the continuity of the outer
organelle around the plastid. The outer organelle may be a mito-
chondrion because it was bounded by a double membrane (circle) and
the density of its matrix is of the same order as the adjacent mito-
chondrion.
(4) Lytic Cells
As was mentioned earlier, electron-dense "pockets" occurred in
the cell wall of adaxial epidermal cells that had bronze pigmentation.
These pockets are inferred to have a role in the breakdown of adja-
cent cell contents. This was the case in the degraded cells of the
palisade region of bronzed leaf tissue. These cells are termed
lytic cells. Lytic cells v/ere the most commonly found cell types in
the palisade layers of bronzed regions. Indeed, the large volume of
air space in the palisade layers of bronzed regions was due to the
removal of palisade cells by degradation.
In Figure 45 the pockets have not penetrated the plasmalemma of
the cell on the right whereas they are seen to have moved into the
cytoplasm of the cell on the left. This suggests that a cell-mediated
response was occurring. In Figure 46 a similar directionality was
evident. On one side of the cell wall appears healthy cytoplasm while
the adajacent cell no longer has an intact plasmalemma, the electron-
V-15
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: dense pockets permeating the cytoplasm except for a few vacuoles.
Normal cytoplasm is no longer recognizable. Certain organelles
were still recognizable in the "pocket-invaded" cell of Figure 47.
The plastid remnants indicate that this was formally a lamellate
type of plastid (arrow). Fragments of the plasmalemma were inter-
spersed with fragments of the cell wall. Similar degradation
occurred in the cell of Figure 48; remnants of a plastid macrogranum
may also be seen (arrow).
(5) Other tissue types
The foregoing description of cell types that occurred in pali-
sade layers of bronzed leaf tissue indicates the diversity of cellular
reactions to increased levels of UV-B. A dramatic reversal of this
trend occurred just below the palisade layers. The delimiting vas-
cular tissue that demarcated the zone of severe UV-B-triggered damage
was relatively unaffected, as seen in the chloroplast of Figure 43,
from a phloem parenchyma cell (morning sample from a one-month-old
plant). The chief structural aberration found in these chloro-
plasts occurred in plants sampled six weeks after emergence. In this
case there was an accumulation of starch, even in morning samples, in
phloem chloroplasts.
The same trend was found in spongy mesophyll tissue of bronzed
regions. Chloroplasts from one-month-old plants had little or no
starch and extensive grana and stroma lamellae, as well as few ribo-
somes (Figure 44, morning sample). However, in contrast to the chloro-
plast in Figure 43 and those in the control tissue, the stroma lamellae
was wavy which indicated an unhealthy condition. As in the phloem
parenchyma chloroplasts the spongy mesophyll chloroplasts were filled
V-16
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with starch in samples from six-week-old plants.
Effect of UV-B Enhancement on Corn Leaf Ultrastructure
On the ultrastructural level, corn leaf tissue was unaffected by UV-B
enhancement. No deleterious affects were found in the structure of cell
organelles in bundle sheath and mesophyll cells.
The lamellar system shown in Figure 49 was from a mesophyll chloro-
plast sampled in the afternoon that was grown under treatment T~
(highest level of UV-B irradiance). There was no difference in the struc-
tures seen here as compared to the control tissue. Note the abundance
of chloroplast ribosomes.
The bundle sheath chloroplast shown in Figure 50 was from the same
treatment (TO, sampled in the morning. The agranal structure of the
chloroplast lamellae is well known and appeared to be no different from the
control tissue. In Figure 51 is shown the corresponding tissue in an after-
noon sample. The bundle sheath chloroplasts contained an abundance of starch
whereas the adajacent mesophyll chloroplast was void of starch. Again,
this was typical of corn leaf tissue and may be said to no different
from the control tissue.
SEM of Citrus
No significant difference between exposed and non-exposed citrus leaf
surfaces were found. The abaxial surface of grapefruit on trifoliate
rootstock is shown in Figures 52 and 43 (control tissue) and in Figures
53 and 55 (UV-B-treated tissue). There appeared to be no significant
differences in treatments. The adaxial leaf surfaces of some of the same
cultivars are shown in Figures 56 and 57. The control tissue (Figure 56)
contained surface waxes, the uneven distribution probably due to weathering.
As seen in Figure 57 the UV-B-treated tissue is also capable of surface
wax deposition.
V-17
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DISCUSSION
This study dealt with structural analyses of leaf tissue placed
under UV-B stress. The analyses correlated light and electron micro-
scopy data and the tissue of interest was that of the mesophyll region.
Photosynthesis, and hence the productivity of agricultural systems, is
primarily dependent upon processes that occur within this region. There
is uncertainty and disagreement as to the effect of certain trace gases
on atmospheric ozone levels, the effect of ozone on the terrestrial
levels of UV-B, and the effects of UV-B on biological systems. The
UV-B enhancement growth regimes used in this investigation cover a wide
range (1.31 UV-Bseu to 2.25 UV-BsฃU). The effects produced by this
stress are qualitatively similar in all treatment levels and may be
a general response to UV-B stress in soybeans, as well as other plants.
The following discussion contains several references to investi-
gations utilizing UV-C (200-280 nm). It should be kept in mind that
plant responses to UV-C may be different than their responses to UV-B
(Caldwell, 1971).
The evidence accumulated during this study confirms the findings
of Van et_ _a]_. (1976) that soybean is a species sensitive to enhanced
UV-B irradiance. Along with several other species they found soybean
to sustain a loss of fresh and dry weight as well as a reduction in
photosynthesis (as net C02 uptake) when subjected to UV-B stress.
The most prominent symptomology of UV-B stress in soybean leaves
was the development of chlorosis. While green tissue of irradiated
leaves showed no abnormal structures, the fine structure of chlorotic
chloroplasts showed a reduced lamellar system, reduced levels of starch
and a reduction in chloroplast size. These characteristics would
V-18
-------
understandably contribute to a reduction in photosynthesis.
Plants grown under hligh light intensities characteristically
develop reduced chloroplast lamellar systems compared to the lamellar
systems they develop under shade conditions (Lyttleton et_ al_., 1971;
Bjorkman et^ a\_., 1972). Whether the reduced lamellar system we
found in chlorotic soybean chloroplasts was due to high levels of
UV-B or rather to reduced levels of chlorophyll (chl) is not clear.
The development of chloroplast lamellar systems is dependent upon
a complex relationship between lamellar protein synthesis and chl
synthesis (Anderson, 1975).
Ballantine and Forde (1970) studied the effect of high and low
temperature and light treatments on soybean leaf ultrastructure. They
found a reduced lamellar system in chloroplasts grown under high
light intensities (400-700 nm) correlated with reduced levels of
chl. -
Campbell (1975) studied ultrastructural changes in field-grown
soybean leaf meosphyll tissue under enhanced UV-B. Interestingly, he
made no mention of abnormal pigmentations. This may be due to the pre-
sence of relatively high amounts of photoreactivating radiation in
the field. Tanada and Hendrix (1953) found the accelerated chloro-
sis induced by UV-C irradiation of soybean to be photoreactivatable.
Campbell's micrographs give no indication of structures we have found
to be associated with abnormal leaf pigmentation. He more commonly
found vesiculation apparently due to the disruption of the tonoplast
and, in a few cells, chloroplasts had disrupted envelopes. He
attributed this damage to senescence that was accelerated by UV-B
V-19
-------
\ treatment. However, we feel "accelerated senescence" to be a nebulous
term used by many authors when damage to stressed tissue cannot be
better described.
! In a study of enhanced UV-B effects of greenhouse-grown pea
Brandle et al_. (1977) found up to 26% of leaf mesophyll cells to
exhibit damage after 16 days of treatment. In chloroplasts, this
progressed from a dilation of thylakoids to a disruption of the enve-
lope and, in the most severe cases, vesiculations of the thylakoids.
Again, no mention was made of abnormal pigmentation. These workers
attributed an inhibition of PS II and damaged chloroplasts to the de-
pressed photosynthetic rates they found in irradiated plants.
Berg and Garrard (1976) irradiated haploid tobacco plant leaves
with monochromatic UV-B (298 nm) at a total dose of 19200 Jnf2
P
(32 Wm for 10 min). No photoreactivating wavelengths were involved,
the tissue was kept in the dark for an induction period. In an exami-
nation of the ultrastructure of leaf mesophyll tissue, they found a
dilation of thylakoids and stromal lamellae as well as an undulating
membrane profile throughout the chloroplast lamellar system. No
pigmentation changes were found.
Sisson and Caldwell (1976) found UV-B irradiation of Rumex
(UV-B-sensitive) to produce no changes in chl levels in the field or
in a controled environment, though treatment caused an inhibition of
photosynthesis. Alternatively, Garrard et_ al_. (1976) found a reduction
in chl levels of bean and cabbage irradiated with enhanced UV-B in a
growth chamber. These workers also found decreased levels of the major
carbohydrate components of several irradiated species.
V-20
-------
In general, one of the most commonly documented detrimental
effects of UV-B stress .in plants if the effect on photosynthesis,
and this was manifested in altered chloroplast structure for most
dicotyledonous species examined.
In an interesting series of papers (Wu, 1971; Wu e_t al_. 1973;
Skokut et a]_., 1977) Wu and coworkers examined the effect of UV-C
(254 nm) on detached leaves of tobacco. They found an accelerated
leaf chlorosis to be accompanied by degradation of chloroplast
.lamellae though high doses seemed to inhibit degradation enzymes.
The UV effect could be eliminated by removing the irradiated epi-
dermis or by floating irradiated tissue on water. These investi-
gators suggested that accelerated chlorosis was due to an indirect
effect of the (irradiated) epidermis possibly mediated by some
toxic substance(s) released from the epidermal cells. Siegel and
Corn (1974) found evidence for a translocatable factor causing
membrane lysis in UV-C-irradiated beet.
The production of such a factor may be a defense mechanism
of the plant in response to UV (Caldwell, 1971). Lautenschlager-
Fleury (1955) found the production of a UV-absorbing compound in
bean to be water-soluble. Caldwell (1968) found a UV-induced UV-absor-
ber to be soluble in methanol/water/HCl and indicated these, substances
to be flavonoids and related phenolics. Both of these workers found
a correlation between increased levels of UV radiation and decreased
epidermal transmission of UV, probably due to the production of these
substances. Shibata (1915) determined that the epidermal and underlying
mesophyll cells of UV-irradiated leaves contained large quantities of
V-21
-------
UV-absorbing flavone derivatives. Caldwell (1971) indicated that
UV absorption in the outer leaf tissues offers plant protection
from UV-induced damage and that flavonoids and related phenolic
compounds (including the anthocyanin group) were probably some of
the most important compounds in the extinction of UV in epidermal
and subepidermal layers of plant tissue.
The production of bronzed pigmentation in soybean leaves ir-
radiated with UV-B shown to occur in this study was probably due to
the presence of similar groups of phenolic compounds. Krizek and
coworkers (Ambler et ^1_., 1975; Krizek, 1975) found UV-B enhanced
growth regimes to induce bronzing in cotyledons of soybean and other
species. Cline and Salisbury (1966) suggested the bronzing found in
Xanthium leaves irradiated with UV-C to be due to the formation of
oxidized polymerized phenolic products subsequent to UV-caused cell
damage. The vein-limitation of these areas, as well as their re-
striction to the adaxial epidermis and palisade layers indicated these
factors to be mobile and water soluble.
Bridge and Klarman (1973) have shown UV-C to cause bronzing
in soybean seedlings and they showed the bronzing to be due to pro-
duction of hydroxyphaseollin, a phenolic compound known to be component
of hypersensitivity reactions. Inoculation of bronzed areas of sus-
ceptible plants with pathogenic fungi (Phytophthora^ megasperma var. sojae)
showed bronzing to confer a degree of resistance to infection. Simi-
larly, Hadwiger and Schwochau (1971) induced phenylalanine ammonia lyase
(PAL) and biosynthesis of pisatin in pea irradiated with UV-C. The'se
are phenolic components of the hypersensitivity reaction of pea plants
and the reaction appears to be dependent on new RNA and protein synthesis.
V-22
-------
: The authors proposed that the control of these responses occurs at
the gene transcription level and depends on the conformational state
of the double-stranded DNA. They indicated the UV-treatment to cause
a change in the conformation of DNA which induces PAL and pi satin formation.
Our authors showed that the most extensive bronzing first occurred
in tissue within the leaf closest to the UV source (i.e., the adaxial
epidermis). At later stages bronzing appeared in the palisade layers.
It was not clear whether or not damage to the epidermis induced bronzing
in the palisade lauers. It may be that damaging of epidermal layers
allowed UV penetration to the palisade layers and the concomitant b
bronzing reaction there. In addition, the bronzing reaction in the epi-
dermal cells could cause a release of a mobile factor that in turn ef-
fects the bronzing reaction in palisade layers. The latter interpre-
tation would better explain the restriction within the leaf of the
reaction, i.e., a mobile factor would be mobilized in the phloem before
it could reach the lower part of the leaf.
That come unknown compound may become mobile in vascular tissue is
evidenced by the pattern of chlorosis and bronzing found in UV-B-irra-
diated leaves. The diffuse "outer" edge of this pigmentation occurs in
a region of minor veins, whereas the sharp edges occur at major veins.
This we hypothesize to be due to a preferential unloading by phloem tis-
sue of a mobile compound which elicits chlorosis and bronzing in leaf
tissue. Produced as a response to enhanced UV-B radiation, after a
.few day's growth this material has become mobilized and translocated to
several leaves wherein symptoms are produced. We are presently studying
the effect of this (hypothesized) compound on phenolic compounds in the cell
wall
V-23
-------
compartment. The observed effects may result from altered phenolic
metabolism in the cell'wall (lignin synthesis may be disturbed) that
results in a heavy concentration of relatively simple phenols. We
are using TLC and colorimetric histochemistry in our studies.
Preliminary results indicate to us that a major response in plants
\
irradiated with enhanced UV-B is that of increased production of phe-
nolic compounds.
Our micrographs showed the bronzing reaction not to occur in the
spongy mesophyll. Although the chloroplasts in this region appear
normal during early growth of the plant, there was a persistence
of starch in samples from older plants which indicated that these
cells may eventually be adversely affected by UV-B stress.
Phenolic compounds are capable of cell damage (e.g., their
effect in the hypersensitivity reaction). The large reduction in num-
bers of palisade cells in bronzed regions was due to cell degradation.
On the ultrastructural level, we associated the electron-dense areas
of bronzed cell walls with phenolic compounds that eventually moved
into the cytoplasm and caused cell death.
Cellular degradation observed in the lytic cell type is associated
with these electron-dense pockets and degradation is probably effected
by phenols.
The variety of unusual cell types we found in bronzed regions of
UV-B-irradiated tissue have not previously been reported in association
with UV damage. Brandle et jil_. (1977) did not find abnormal structures
~l~~1 r ~"
(except for a slight dilation of thylakoids) in intact chloroplasts
from pea leaf tissue irradiated with UV-B. Similarly, Skokut et al.
V-24
-------
(1977), using UV-C, reported only "wavy" stroma and high numbers of
plastoglobuli in intact chloroplasts of irradiated tobacco leaves.
The paucity of reports in the literature on UV effects on plant ultra-
structure would explain this lack of corroboration of our data.
Caldwell (1971) stressed the significance of the UV-B absorption
spectra of nucleic acids and proteins (which are very similar in the
UV-B region) in describing the action spectrum of plant response to
UV-B. UV absorption by membrane proteins could possibly alter their
structure and, concomitantly, membrane structure. This would explain
the effect of UV on the quality of membranes (e.g., permeability,
undulating profiles, lack of thylakoid appression, incongrous chan-
neling of excitation energy in photosynthesis). We propose that the
altered cellular structure found with UV-B-enhanced irradiation of
soybean leaf tissue to be primarily due to damage incurred by nucleic
acids and proteins with absorption of this radiation. This proposal is
based upon evidence gathered from published studies of the effects of
chloroplast ribosomes (versus cytoplasmic ribosome) inhibitors and from
mutant studies. Mutations cause alterations in physiology which often
are manifested in cell fine structure. This alteration in physiology
forms the basis for our comparison with'mutation studies.
We are presented with an unusual situation in interpretation of
the atypical cell types. They developed in apparently normal green
leaves a few days after emergence. The green appearance of the leaves
indicated the presence of healthy chloroplasts. The appearance of
chlorosis and bronzing was accompanied by development of the cell '
types. This would indicate the cell types to be a result of degenera-
tion of healthy cells and this is what we suggest is occurring.
V-25
-------
The noteworthy occurrence here is that the degenerated structures are
similar in apperance to structures found in incompletely developed
plastids, though our samples were made of fully expanded (mature)
leaves.
In vesiculate cell types organelles other than plastids and mito-
chondria appear normal. Though aberrations in the metabolism of
mitochondria may cause plastid degeneration (Wettstein and Eriksson,
1965) this is probably not the case here because of the occurrence
of vesiculate plastids in mixed cells with chloroplasts. Indeed,
it appears that the metabolic processes responsible are within
the plastid.
Thompson and Ellis (1972) treated greening pea leaves with the
antibiotic lincomycin which is a specific inhibitor of 70 S (plastid)
ribosomes. They found this treatment to interfere with the formation
of normal lamellar systems in- chloroplasts and that treated chloro-
plasts contained vesiculated lamellae interspersed with macrogranum,
i.e., similar structures to those found in vesiculate plastids.
Heslop-Harrison (1962) treated hemp plants with the pyrimidine analo-
gue, 2-thiouracil, which interferes with chloroplast protein syn-
thesis, and found this to cause a vesiculation of chloroplast
lamellae. Machold (1971) treated bean leaves with the 70 S ribo-
some inhibitors streptomycin and chloramphenicol and found this
to cause an inhibition of the synthesis of four lamellar proteins
in chloroplasts. The ultrastructure of chloramphenicol-treated
bean leaves was studied by Bra.dbeer ejt aj_. (1974) and they found
vesiculation in the stroma of chloroplasts accompanied by larger
V-26
-------
and fewer grana as compared to the control tissue. It is evident
from the above studies that alteration of chloroplast ribosome meta-
bolism (i.e., chloroplast protein systhesis) causes an increase of
granum size (macrograna) and a loss of stromal lamellae. The
latter appears to be replaced by numerous small vesicles in the
stroma. Chloramphenicol binds specifically to plastid ribosomes
(Kung, 1977). Proteins synthesized on plastid ribosomes are
essential in the formation of a functional thylakoid membrane (Eytan
and Ohad, 1970; Anderson, 1975). Thus, it appears that the aberrant
lamellar system of vesiculate plastids is due to dysfunction of plas-
tid ribosomes in these plastids. This may be due to dimerization of
component nucleic acids by enhanced UV-B levels. It cannot be ruled
out that the effect could be on plastid DNA, which codes for plastid
r-RNA (Kung, 1977). There appears to be plastid ribosomes present
in our micrographs of vesiculate plastids (Figure 16).
It is interesting to note that chloramphenicol causes an inhi-
bition of the synthesis of the large subunit. of Fraction 1 Protein
(Kung, 1977) and that we found a corresponding decrease in RuDP
carboxylase activity (Section IV) as well as a lack of starch in
vesiculate plastids. Again, we emphasize the occurrence of the plas-
tids in mixed cells to show that the vesiculate plastid is not due to
aberrations in nuclear or cytoplasmic metabolism (Wildman et al.,
1973; Wong-Staal and Wildman, 1973; Kirk and Tilney-Bassett, 1967).
A plastid mutant in mixed cells of variegated leaves of Tradescantia
was shown by Gyurjan et^ al_. (1977) to contain macrograna, some of
the thylakoids'of these macrograna were dilated, as is found in some
vesiculate plastids.
V-27
-------
Macrograna are found in both vesiculate and lamellate cell
types. There are many published micrographs of macrograna. They
appear in rust-infected tissue of flax (Coffey ert al_., 1972)
and in virus-infected leaf tissue of tomato (Arnott et^ a]_., 1969).
They are found in mutants of barley (Wettstein, 1960), corn (Bachmann
ฃt al_., 1967; Orsenigo and Marziani, 1971), and tobacco (Schmid
et a]_., 1966). Bachmann ฃt aj_. (1969) considered macrogranum in a
pastel mutant of corn to be true grana, i.e., composed of chl-containing
thylakoids with an intrathylakoid space and with adjacent thylakoids
appressed. Smith and Sjolund (1975), using tissue cultures of Strep-
tanthus tortuosua that contained chloroplasts having macrogranum,
showed that no PS II activity occurred in macrograna although PS I
activity was present. Macrogranum formation in this case was due
to the presence of viruslike particles in nucleoli. It is of interest
to note that PS II activity is inhibited by UV-B. Macrogranum in the
xantha-15 mutant of barley contain chl (Wettstein, 1961). When Walles
(1963) grew the xantha-23 mutant of barley on minimal media supple-
mented with leucine, he was able to eliminate macrograna formation
and the chloroplasts developed normal lamellae. These structures seem
to be common in plastids located in tissue with disturbed metabolism.
Since the atypical cell types found in this investigation appeared
in previously healthy tissue, we feel the unusual structures to be
degenerative in nature. While this is perhaps not so obvious in the
vesiculate cell type, it is much more so in the lamellate cell type.
All organelles and membranes appear dysfunctional in this type.
Interestingly, the plastids often persist over the other organelles.
However, judging by plastid structure, these organelles are hardly
V-28
-------
photosynthesizing. Lamellate plastids are not found in mixed cells
and their structure is probably due to the irregular nature of
the rest of the cell.
Lamellate plastids commonly contain closely grouped aggregates
of thylakoids in regular spacing. Termed primary thylakoids, they
are not appressed though they often contain tightly appressed grana
in their arrays. Bachmann et_ a\_. (1969) termed these structures
"parallel thylakoids" and found them to occur in several corn
mutants, especially when they were grown under dim light. They
appeared to result from incomplete development of the lamellar
system. These workers attributed this atypical structure to subop-
timal conditions, either genetic or environmental, and did not con-
sider them to be true grana. We attribute them to the abnormal
condition of enhanced UV-B radiation. Primary thylakoids are found
in other nuclear mutants of barley (Wettstein e_t al_., 1971), corn
(Orsenigo and Marziani, 1971), and tobacco (Schmid et_ al_., 1966).
Stacking of thylakoids is apparently under nuclear control (Anderson,
1975). In the lamellate cell type, the obvious condition of the
nucleus would explain the aberrant plastid lamellar structure.
Note that no plastid ribosomes are found in these plastids.
Of the three anomalous cell types found in bronzed regions, the
plastids in alamellate cells appear most like degenerating plastids.
Mitochondria are the only other abnormal organelles in this type.
It is doubtful that mitochondria of these cells influence the plastid
structures since these plastids occur also in mixed cells along with
chloroplasts and vesiculate plastids. Their occurrence in mixed cells
implied that the causal mechanisms for the alamellate plastid
V-29
-------
; structure resides in the individual plastid. These plastids have no
typical lamellar structure (i.e., thylakoids) and no apparent ribo-
somes. The stroma is homogenous. Similar features were found by
1 Walles (1965) in non-allelic carotene-less mutant of sunflower.
Grown under dim light, the mutant contained lamellae and chl a_ and
b^which became photooxidized with increased levels of light. This
was accompanied by a degeneration of the plastids which formed
loose membranes and a homogenous stroma. Corn mutants grown under
similar conditions also produced degenerated plastids similar to
alamellate plastids (Bachmann ฃt a\_., 1969). The circular grana
found in some alamellate plastids have been reported in the xantha-
1 n
b mutant of barley (Sager, 1972) and a mutant of corn (Orsenigo
and Marziani, 1971). Again, the similarity of alamellate plastid
structure to those reported in various mutants indicates a response
via altered cell physiology probably due to lesions in nucleic acids
or proteins caused by UV-B absorption. That these plastids occur
in mixed cells indicates the altered metabolism occurs within indi-
vidual plastids. The presence of a true plastid mutation cannot be
determined easily in this situation because of the need for propa-
gation of the cells in question.
Our finding of degenerate plastids (vesiculate and alamellate)
in cells containing chloroplasts indicated that this degeneration is
under plastid control to some extent, and that plastids may respond
to enhanced UV-B on an individual basis.
A feature common to all atypical cell types (and chlorotic cells)
is the occasional occurrence of mitochondria within invaginations
of plastids. This phenomena was noted to occur in soybean leaves
V-30
-------
grown under low light intensities by Ballantine and Forde (1970).
Montes and Bradbeer (1976) also reported this effect as a response
to low light conditions in corn and Hyptis. They suggested this as-
sociation allows for energy compounds (produced by mitochondria)
to be utilized by chloroplasts in maintaining their basal metabolism
with low light conditions. Wildman et^ al_. (1973) suggested that
this close association occurred in their mutant tobacco plants
(plastid mutant), as observed by phase microscopy of living cells.
Phytoferritin and plastoglobuli found in atypical plastids are
presumed to result from accumulation during the degeneration of these
plastids (Thompson, 1974).
The data presented here, taken with data presented elsewhere in
this report, implicates UV-B-enhanced growth regimes in the develop-
ment of detrimental cell structure of soybean leaves.
The apparent lack of detrimental effect of UV-B stress on corn
leaf ultrastructure is interesting and may have some basis in this
species being widely separated from soybean and in the erect habitat
of the corn plant.
The apparent lack of effect of UV-B-enhancement on citrus leaf
surfaces also indicates the variation in species resistance to this
stress.
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pp. 447-452, North-Hoiladn, Amsterdam.
\
28) Machold, 0. 1971. Lamellar proteins of green and chlorotic chloro-
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V-36
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ซ
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-------
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V-40
-------
I TABLE 1.
; DEVELOPMENT OF LEAF CHLOROSIS IN SOYBEAN WITH DIFFERENT LEVELS OF
' UV-B IRRADIATION-/
Leaf number
Leaf age
3 days
4 days
7 days
9 days
11 days
15 dyas
4/
Leaf size-'
(cm)
width
length
Order of
increasing 5/
pigmentation-'
Seyerity
across treatments
6/
2.8 2.8
5.8 5.0
4.1 3.1
6.7 6.8
3.4 4.5
6.4 6.7
2
3
1
2
1
3
3
2
1
1
2
3
2
1
3
1
2
3
c
7 8
G^
P
IP
I
NC
NC
G
P
IP
IP
NC
NC
G
P
IP
i
NC
NC
G
G
P
IP
NC
NC
G
P
IP
NC
NC
NC
G
P
IP
NC
NC
NC
G
NC
NC
NC
NC
NC
G
NC
NC
NC
NC
NC
4.6 4.1
6.4 7.2
1 1
Glycine max cv. 'Bragg1; development'on two-week-old plants of
two trifoliate leaves per treatment was followed from emergence
to 15 days' growth; chlorosis as presence of yellow-white pigment
areas.
2/
See text for explanation of irradiance levels.
o /
Grading symbols: G=green, p-slight pigmentation area, P=substantial
pigmentation area, i=slight increase in degree of pigmentation, 1=
substantial increase in degree of pigmentation, NC=No change.
Terminal trifoliate leaflet.
-Within each leaf, leaflet number order illustrated; no difference in
the controls.
- Severity of non-green pigmentation, 6=most severe.
-------
LIST OF FIGURES
Figures 1-4.
Plate I
Figure 1
Figure 2
Figure 3
Figure 4
\
A comparison of soybean trifoliate leaves
grown under various UV-B enhancement regimes
(leaves two weeks old, see text for treatment
levels).
(upper right). Leaf from T-,.
(upper left). Leaf from control.
(lower left). Leaf from T2-
(lower right). Leaf from T.
Plate II
Figures 5-10.
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Pigmentation of UV-B-irradiated soybean leaves.
(upper left). Two-week-old leaf showing
chlorosis and bronzing.
(middle left). Leaf surface of chlorotic/
bronzed region.
(lower left). Light micrograph, surface view,
of border between green and bronzed leaf
regions (200 X).
(upper right). Light micrograph transverse
section of control (green) tissue (500 x)-
(middle right). Light micrograph transverse
section of chlorotic leaf region (500 x).
(lower right). Light micrograph transverse
section of bronzed leaf region (micrograph
upside down, 500X ).
-------
All electron micrographs are of soybean leaf mesophyll unless otherwise
stated.
Plate III
Figure 11
Figure 12
Figure 13
Figure 14
Chloroplast from green region of soybean
leaf irradiated with UV-B (22,400 X).
Chloroplasts from chlorotic leaf region
(26,000 x).
Bronzed adaxial epidermal and palisade cells
(7,300 X).
Collapsed bronzed adaxial epidermal cells
(18,000 X).
Plate IV
Figure 15
Figures 16-17
Vesiculate cell from bronzed leaf region
(13,000 X).
Vesiculate plastids. Figure 16 - 18,000 X.
Figure 17 - 16,000 X.
Plate V
Figures 18-19
Figure 20
Vesiculate plastids. Figure 18 - 36,000 X
Figure 19 - 9,000 X.
Palisade chloroplast with lamellate-type
stromal lamellae (16,000 X).
-------
Plate VI
Figure 21
Figures 22-23
Lamellate cell (6,200 X; inset - 12,000 X).
Lamellate plastids. Figure 22 - 12,000 X.
Figure 23 - 23,000 X-
Plate VII
Figures 24-27
Lamellate plastids. Figure 24 - 25,000 X;
Figure 25 - 28,000 x; Figure 26 - 77,000.x;
Figure 27 - 69,000 X-
Plate VIII
Figure 28
Figure 29
Alamellate cell (16,200 X; inset 59,000 X).
Alamellate plastid (36,000 x).
Plate IX
Figures 30-36
Alamellate plastid structures (Figures 32-34
serial sections). Figure 30 - 32,000 X; Figure
31 - 32,000 X; Figure 32 - 20,000 X; Figure
33 - 20,000 x; Figure 34 - 20,000 x; Figure
35 - 23,000 x; Figure 36 - 100,000x
Plate X
Figure 37
Figure 38
Figure 39
Alamellate plastid (29,000 x).
Vesiculate plastid in mixed cell (12,000 X).
Mixed cell containing chloroplasts, vesiculate,
and alamellate plastids (11.300X.).
-------
Figure 40
Chloroplast from cell of Figure 39 (27,000 X)
Plate XI
Figures 41-42
Figure 43.
Figure 44
Serial sections of an alamellate plastid within
an organellar invagination, mixed cell (28,000
X, both micrographs).
Phloem parenchyma chloroplast in bronzed leaf
region (37,000 X).
Spongy mesophyll cell in bronzed leaf region
(16,500 X).
Plate XII
Figures 45-48
Lytic cells of bronzed region. Figure 45 -
37,000 X; Figure 46 - 27,000 X; Figure 47 -
37,000 X; Figure 48 - 18,000 X.
Plate XIII
Figures 49-51
Structure of corn leaf tissue irradiated with
UV-B. Figure 49 - 110,000 X; Figure 50 -
16,000 X, morning sample; Figure 51 - 7,000 X,
afternoon sample.
Plate XIV
Figures 52-57.
Scanning EM of citrus leaves irradiated with
UV-B in the field. Figures 52, 54, 56: control
Figures 53, 55, 57: treatment. Figure 52 -
-------
. 200 x; Figure 53 - 200 X; Figure 54 - 5,000 X;
Figure 55 - 5,000 X; Figure 56 - 2,000 X;
Figure 57 - 5,000 X.
-------
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PLATE XIV
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wfwM;u ^
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-------
FINAL REPORT
HIGH ALTITUDE STUDIES OF NATURAL, SUPPLEMENTAL
AND DELETION OF UV-B ON VEGETABLES AND WHEAT
F. D. Moore III
M. J. Burke
M. R. Becwar
Horticulture Department
Colorado State University
Fort Collins, Colorado 80523
EPA-IAG-D7-0168
ARS-12-14-1001-717
Project Officer:
R. J. McCracken
Agricultural Research, Science and Education Administration
U.S. Department of Agriculture
Washington, D.C. 20250
This study was conducted
in cooperation with
U.S. Department of Agriculture
Beltsville, Maryland 20705
Prepared for
Environmental Protection Agency
EAGER Program
Washington, D.C. 20460 .
-------
EPA REPORT NUMBER EPA-IAG-D7-0168
Published with the
approval of the Director,
Colorado State University
Experiment Station, Fort Collins,
as Scientific Series No. 2356
-------
FORWARD
Decisions having great impact must be made with regard to inadvertent
modification of the upper stratosphere. It will be difficult to make such
decisions due to insufficient hard data. Man's sustenance is at stake and
thorough and rapid investigation is necessary.
There is need to know whether man's traditional food crops are adapted
to enhanced levels of UV-B radiation which will result from stratospheric
ozone depletion. The Colorado State University Horticulture group contributed
to this interdisciplinary effort through research focused on enhancement of
solar UV-B by means of filtered sunlamps as well as exclusion methods. These
studies were conducted at high altitude with four crop species of internation-
al importance.
ii
-------
ABSTRACT
Our research was initiated in order to determine the influence of
solar UV-B and solar supplemented UV-B radiation on wheat, Triticum
aestivum; potato, Solanum tuberosum; radish, Raphanus sativus; pea,
Pisum sativum and also to develop dose-response information including
threshold UV-B levels for injury.
A field program was initiated at a site at 3000 m elevation,
39ฐll'N latitude and 106ฐ56'W longitude located 43 km W of the Continental
Divide and 11 km from the nearest highway.
Filtered sunlamps were employed in one experiment and UV-B trans-
mitting films, a UV-B absorbing film, and 26% shade were used as treat-
ments in another experiment. Plants were grown in containers in an
artificial medium. Exposure began at emergence, June 23 and ended on
August 13.
The only significant response by plants exposed to UV-B simulating at
least a 20% reduction in ozone was that of stature reduction in wheat.
It was discovered in the experiment where solar UV-B was supplemented
with lamp UV-B that various factors associated with the technique preclude
any rigid interpretation of the data.
i>
Technical information regarding Aclar , a UV-B transmitting film;
lamp output relative to temperature; lamp variability; was gathered and
a new approach to UV-B studies was suggested.
iii
-------
CONTENTS
Foreward ii
Abstract ill
Figures and Tables v
Abbreviations and Symbols vii
Acknowledgment x
1. Introduction 1
2. Conclusions 3
3. Recommendations 3
4. Materials and Methods 4
5. Results and Discussion 16
References 32
Bibliography 33
Appendices 35
iv
-------
FIGURES
Number Page
1 Container - artificial medium culture of pea, wheat, potato,
and radish used in the exclusion and lamp studies 6
2 Graphic analysis of the sun position at the Colorado site
during the exposure period, June 23 - August 13 7
3 Exclusion study frames 91.5 x 213.5 cm, angle steel with
adjustable steel pipe legs 9
4 Sun spectra measured with the BARC Instrumentation Laboratory
IRL Spec. D spectroradiometer and an ISCO spectroradiometer... 10
5 Sun spectra measured with the BARC Instrumentation Laboratory
IRL Spec. D spectroradiometer 11
6 Lamp study conduit frames a 96 x 127 cm structure suspending
2 fixtures, 4 FS40 sunlamps, 110 cm above plants 12
7 Cellulose acetate filtered FS40 lamp spectra and broad band
summation measured with the BARC IRL Spec. D spectroradiometer
at night 14
8 Comparison of cellulose acetate filtered and Mylar filtered FS40
lamp spectra. Measurements made with the BARC Instrumentation
Laboratory IRL Spec. D spectroradiometer and an ISCO spectro-
radiometer at night 15
9 Experimental area depicting lamp and exclusion structure
positioning at 3000 m elevation . 17
10 Comparison of solar UV-B spectra on two different "bright" days
in August in Beltsville and the Colorado site measured with
the same IRL Spec. D spectroradiometer 19
11 Wheat plant height as a function of UV-B exclusion (M = Mylar)
and UV-B transmission (CA = cellulose acetate and
AC = Aclar) 20
12 Wheat plant height in the open relative to 26% shade
equivalent to sea level insolation 21
13 Comparison of the three lamp treatment responses with broad
band UV-B irradiance held constant. Dry weights are the
sum of the two plants . 24
-------
FIGURES (cont.)
Number
14 Comparison of the three lamp treatment responses with
broad band UV-B irradiance held constant 25
15 Comparison of interaction means fitted to linear models,
294 hrs lamp exposure during 49 days 26
16 Wheat plant height as a function of diagonal distance from
center of lamp fixtures (plant plane) and irradiance.
Measurements made with the IRL Spec. D, spectroradiometer
at night 29
TABLES
1 Growing medium properties 5
2 Exclusion study, environmental parameters, potato 13
vi
-------
LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS
UV-B
CA
AC
M
U
NL
+UVB
-UVB
UV-A
PAR
AST
MDT
BARC
UVBSE
AC9
FW
DW
14-14-14
irradiance in the 280-320 nm range
cellulose acetate film transmitting UV-B
Aclar film,transmitting UV-B
Mylar film, does not transmit UV-B
unlit or non-lamp, no emmission of energy
designation for treatments permitting UV-B
designation for treatments preventing UV-B
irradiance in the 320-400 nm range
photosynthetically active radiation
400-700 nm range
apparent solar time
mountain daylight time
Beltsville Agricultural Research Center
UV-B sun equivalents, a function of weighted
(action spectrum applied) irradiance in the
UV-B range - developed by BARC, UVBSE x 3.06 =
weighted mW.nr2 (280-320nm)
refers to actual equation
y = [0.25 a/228.178)9'0 ] exp. [4-(X/228.178)9'ฐ]
and weights for biological
effectiveness X<320 nm, developed by BARC
fresh weight, not dried
dry weight - obtained by drying tissue in a
forced draft oven at 70ฐ C for 48 hrs
slow release fertilizer, 14% nitrogen + 14%
phosphate + 14% potash
vii
-------
FS40
nm
-2
mW.m
Error a
Error b
df
MS
LSD
CdS
mmhos/cm
pH
mil
bar
SYMBOLS
R2
Y = aX
Westinghouse sunlamp designation
nanometers
milliwatts per meter squared
whole plot error used to test - UVB effect
subplot error used to test irradiance and
- UVB x irradiance interaction
degrees of freedom
mean square
least significant difference,
refers to mean separation
cadmium sulfide
a measure of conductivity and related
to soluble salt concentration
-log..- of the reciprocal of the H ion
concentration, a measure of active acidity
2.54 mm 0.254 mm or 0.001 inches
-2
**
750 mmHg or 99998 N.m
coefficient of determination, percent
indicates the extent of variability
in the dependent variable accounted for
by the model
general form for power model
arithmetic mean
significant at 5% level
significant at 1% level
viii
-------
P phosphorus
K potassium
Fe iron
Zn zinc
Cu copper
Mn manganese
Mo molybdenum
S sulfur
N0_ - N --nitrate nitrogen
Ca(H PO.) . H_0 triple super phosphate
\
KNO, potassium nitrate
(NH,)7SO, ammonium sulfate
NiSO + CoSO, nickel sulfate plus cobalt sulfate, a liquid filter
ix
-------
ACKNOWLEDGEMENTS
We wish to acknowledge the continued cooperation of Aspen Skiing
Corporation. Among other things, they provided the 3000 m site at the
Snowmass Mountain Facility. We are particularly indebted to Mr. James
Snobble, Mountain manager, and Mr. Robert Clark, Supervisor for their
help including "emergency" type decisions made on the mountain. Ms.
Ann McSay, Senior Research Technician in Horticulture deserves praise
for her dedicated involvement in the project from beginning to end. We
are happy to take the opportunity to thank the students both graduate and
undergraduate who helped as they learned. They are Joseph Freeman,
Debora Stevens, Tracy Sulzbach, Phoebe McCoy, C. Rajashekar and Robert
Morris as well as Daniel Pskowski, Laurie Maxwell, Cheryl Hoffman and
Douglas Drake. We also acknowledge the help of Thomas Knoblock a former
student and resident of Aspen who provided handyman expertise when we need-
ed it and Karen Hulse for data collection and analyses. A special note of
appreciation goes to Dr. Frank Ronco of the U.S. Forest Service, former
project leader of the spruce-pine investigation at the site. We wish to
thank Dr. Ronco in particular for his design of the waterproof lamp
fixtures and lamp structures and for the aid of his staff, Mr. Nelson
and Mr. Ross.
Dr. Harry R. Cams, Chairman, Plant Physiology Institute USDA, ARS
and his staff including Dr. Krizek and Mr. Rowan are acknowledged for
their help particularly with the actual measurement of the UV-B irradiance
on the mountain. Mr. Daniel Rowan actually spent a week with the IRL
-------
Spec. D making measurements on the mountain. Mr. Michael Becwar, Ph.D.
candidate and one of the authors of this report is to be congratulated
for assuming full responsibility at the site so soon after he arrived
from Oregon State University. Many thanks to Mrs. Jonilyn Hall for
careful typing of the manuscript.
The Pitkin County Commissioners representing the most forward think-
ing community in the United States are hereby thanked for granting funds
for research which was a prelude to the research carried out as described
in the following pages of this report.
xi
-------
INTRODUCTION
Destruction of the stratospheric ozone due to increased concentration
of halocarbons and nitrogen oxides could have serious impact. A problem
is predicting this impact on food crops. Our study measured the magni-
tude of the impact caused by a realistic increase in solar UV-B radiation
under natural outdoor conditions.
The study was unique in that the research took advantage of the
naturally higher levels of solar UV-B radiation at high altitude. This
was a primary method for increasing natural UV-B radiation levels. There
are many difficulties in reproducing the natural levels of UV-B radiation
using artificial light and some of these difficulties are reviewed by
Sisson and Caldwell (1975). They point out that many of the difficulties
are due in part to the increased effectiveness of shorter wavelengths of
radiation which are present at such low levels. Artificial UV-B radiation
generally has the wrong spectral distribution and intensity and therefore
is not comparable to the natural solar radiation.
Radish and pea were chosen for this study because they originate at
low altitude and because of this, we anticipated little innate UV-B radia-
tion tolerance. Cline and Salisbury (1966) investigated the UV (254 nm)
sensitivity of these two crops and found them to be sensitive and very
sensitive, respectively. They were used for UV-B sensitive plants.
Radish and pea have additional advantages in that they adapt well to the
cool climate and short growing season at our high altitude research plot.
Ergasheve et al (1971) reported photosynthetic impairment in pea seedlings
-------
attributable to high elevation UV. Potato was chosen because it may be
naturally more UV-B tolerant. Potato orginates in high elevation
equatorial regions such as the high valleys and plateaus of Peru and
Bolivia (approximately 4300 m elevation) and as such may be conditioned
to higher levels of UV-B radiation. Although potato is not commercially
grown at northern latitudes at 3000 m elevation it does well under wide
diurnal temperature conditions. In the summer of 1976 reasonable yield
for experimental purposes was obtained at 3200 m in Colorado. A potato
leaf abnormality was noted at 2800 and 3200 m, possibly due to high
irradiance levels. Wheat was chosen because it might also be UV-B
resistant (Krizek, 1975) and because of its considerable importance as a
major food crop.
The elevated site at approximately 3000 m above sea level was chosen
for several reasons. Estimates by Becker and Boyd (1957) would indicate
a 26% increase in insolation while Caldwell's (1968) work suggested an
increase in global biologically effective UV-B irradiance of 2.5% to
12.6%, depending on the sun's zenith angle and air mass. Sauberer (Caldwell,
1968) would predict an increase of 34% UV-B irradiance of undetermined
biological effectiveness. Tousey (1966) and Roller (1965) demonstrated
the presence of the spectral lines 288.1 nm and 286.3 nm, respectively,
at high elevations in the Alps. The anticipated high UV-B radiant flux
density and shorter wavelength UV-B was seen as a natural way to simulate
the effect of ozone depletion.
-------
CONCLUSIONS
1. Solar UV-B irradiance at levels above those equivalent to a 20%
reduction in stratospheric ozone reduced wheat plant stature.
2. Further investigation of solar UV-B by means of filtered lamps
is needed prior to any future field experimentation.
3. Undue concern regarding detrimental effects on biomass resulting
from 20% depletion of stratospheric ozone appear not warranted
according to our investigation of wheat, potato, radish, and
possibly pea.
RECOMMENDATIONS
1. Future research at high altitude should employ neutral density
filtration of the UV-A and PAR regions.
2. The solar UV-B collector and irradiator concept should be
investigated.
3. In any field studies, the UV-B, UV-A and PAR should be monitored
continuously on classified days, so that true dosages may be
ascertained.
4. The photographic technique of Tousey (1966) might be employed
in high altitude studies so that evidence of <280 nm radiation
. might be gathered.
5. Photo-dosimetry should be investigated as a technique to deter-
mine dosages applied to whole plants. This technique would
compensate for individual leaf positioning in relation to the
UV-B source.
-------
6. We suggest a workshop be held on solar UV-B manipulation
techniques.
MATERIALS AND METHODS
Crop species and cultivars tested were: pea, Pisum sativum 'Alaska';
wheat, Triticum aestivum 'Inia 66'; potato, Solanum tuberosum, 'Kennebec1;
and radish, Raphanus sativus, 'Cherry Belle'. All species were grown in
steel containers of 2.4 liter (potato) and 1.2 liter capacity with
drainage provided, Figure 1. An "artificial" medium was used TABLE 1.
The site chosen was at 3000 m elevation, 39ฐ 11 N latitude (BARC is
39ฐ 01 N latitude) and 106ฐ 56 W longitude located 43 km W of the Contin-
ental Divide and 11 km from the nearest highway. The surface was level
and water and electrical power (110 v and 220 v) were available.
During the course of these studies all plants received 10 to 11
hours of direct sunlight per day. The site indicated in Figure 2 is
i
mountainous and heavily forested, however, the site was chosen so that
the horizon in all directions was not higher than 18 from the horizontal
plane.
Two studies were conducted. The first was an exclusion study in-
volving both reduction and filtering of overall insolation including UV-B
radiation. This approach takes advantage of the naturally high levels of
UV-B radiation occurring at 3000 m elevation. The high levels of natural
UV-B radiation were reduced using various filters. Thus, in this ex-
periment the extra UV-B radiation was reduced with filters in such a way
as to simulate stratospheric ozone depletion relative to sea level.
-------
TABLE 1. GROWING MEDIUM PROPERTIES USED IN
LAMP AND EXCLUSION STUDIES
1. 40% peat, 30% vermiculite, and
30% sand by volume.
2. Chemical properties.
pH 5.2
Texture
Organic matter
Conductivity
NO -N
3 P
K
Fe
Zn
Cu
Mn
loamy sand
5.4%
2.5 mmhos/cm
158 ppm
71 ppm
345 ppm
63.4 ppm
8.7 ppm
0.5 ppm
20.4 ppm
Nutrients added per liter of medium.
0.536 g Ca(H2POA)2 . H20
0.357 g KN03
0.179 g (NH4)2S04
0.179 g slow release 14-14-14
0.005 g soluble trace element mix
inert
Mn
Fe
Cu
Zn
B
Mo
S
60.15%
8.15%
7.50%
3.20%
4.50%
1.45%
0.05%
15.00%
3. Water holding properties.
%H20/DW bars
100.0 0.0
49.2 - 0.1
24.0 - 0.3
21.0 - 0.5
18.0 - 1.0
-------
Figure 1. Container - artificial medium culture of pea, wheat, potato, and radish used in
the exclusion and lamp studies.
-------
oป
4>
O
3u
o
jr
<
UJ
O
a:
o
to
iio-
100-
90-
80-
70-
60-
50-
40-
30-
20-
10-
8>
AUG. 21 V*
| i
39*11' N
106ฐ 56' W
JUNE 21
AUG. 21
40*
l i l il j I M i l l i | i i I j l i iฅ i l i l l t l i i t I i i l I i l l i I l l i I l i l I I I l j
8 9 10 II 12 13 14 15
AST (odd Ihr. and lOmln. for HOT)
16 17 18 19 20
Figure 2. Graphic analysis of the sun position at the Colorado site during the exposure period,
June 23 - August 13.
-------
Treatments involved were: 1) an open control 2) a 26% insolation reduction
using lath shading to simulate sea level insolation 3) cellulose acetate
filtering to reduce UV-B radiation levels without substantial reduction in
visible radiation 4) Mylar filtering to essentially eliminate UV-B radia-
tion without substantial reduction in visible radiation and 5) Aclar
filtering to reproduce the microclimate under the above filters without
significant reduction of UV-B or visible radiation. The structures are
illustrated in Figure 3. The transmission properties of Mylar and cellu-
lose acetate are well understood and the transmission spectrum of Aclar
is in Figure A-l (Appendix). Aclar has no significant absorption above
230 nm through the visible region. Filter thicknesses were: cellulose
acetate and Mylar, 5 mil; and Aclar, 1.5 mil. The experimental design
employed was a randomized complete block with three replications per plant
species. Treatment differences were tested by using the F test and if
differences were significant, means were then separated using LSD proce-
dures at the 5% level.
Spectral evaluation of the films in_ situ, as well as thermal analysis
and total insolation measurements, were made with the BARC IRL Spec D spec-
troradiometer, an ISCO spectroradiometer, an Optronics radiometer, a
Barnes IR thermometer, pyranographs, and a Leeds and Northrup recording
potentiometer. Data are presented in Figure 4 and 5 and TABLE 2 and
TABLE A-l (appendix).
-------
Figure 3. Exclusion study frames 91.5 x 213.5 cm, angle steel with adjustable steel pipe legs,
-------
. 1200
HOOh
1000
T 900-
cvi? 80ฐ-
i
? 700
E 600
UJ
o 500-
5 400-
^ 300-
200-
100
EXCLUSION STUDY:
TREATMENT
OPEN
CELLULOSE ACETATE
ACLAR
MYLAR
o
co _ ..
cj ro ro
ooooo
CJ
-------
1000
900
800
- 700
c
CJ
I
Id
O
<
o
600
500
< 400
o:
o:
- 300
200
100
EXCLUSION STUDY:
OPEN
CELLULOSE ACETATE.
ACLAR
MYLAR
280 300 320 340 360 380 400
WAVELENGTH,nm
Figure 5. Sun spectra measured with the BARC Instrumentation Laboratory
IRL Spec. D spectroradiometer.
11
-------
ป-,
s^^^^5^/^
Figure 6. Lamp study conduit frames with a 96 x 127 cm structure suspending 2 fixtures, 4 FS40
sunlamps, 110 cm above plants.
-------
TABLE 2. EXCLUSION STUDY, ENVIRONMENTAL PARAMETERS, POTATO
SOLAR
FILTER
NONE (OPEN)
Cellulose
Acetate
Aclar
Mylar
Shade
Numbers in brackets
HOURLY MEAN SOLAR RADIATION
TEMPERATURE (ฐC) (W/ 2)
m
AIR
12.9
(+0.7)1
( 0.0)
(+0.2)
(-0.2)
indicate
PLANT
12.7
(+1.4)
(+1.5)
(+1.6)
( 0.0)
NATIVE SOIL SOLAR NOON
16.2
(+2.6)
(+1.1)
(+2.7)
(-0.2)
deviation from plants
803
(-63)
(-21)
(-84)
(-208)
growing in the open.
The second study involved supplemental lighting in the field with
Westinghouse FS40 sunlamps. The filtered sunlamps were operated for 6
hours each day (3 hours before and after solar noon) at a distance of
110 cm above the plants. Procedural protocol used with regard to lamps,
lamp filters, lamp reflectors, lighting configuration, filter and lamp
ageing, and filter changing was according to the instrumentation laboratory
BARC. Figure 6 illustrates the basic four-lamp configuration employed.
There were three treatments used. The first was lamps filtered with 5 mil
cellulose acetate. Two control treatments were lamps filtered with Mylar
which transmitted no UV-B radiation and reflectors without lamps to repro-
duce the microclimate of the lamp fixtures without adding radiation. Spec-
tral evaluation of the filtered lamps in situ is presented in Figures 7
and 8. A split plot design was used in the lamp study with whole plots
13
-------
LAMP STUDY:
SPECTRA IRRADIANCE (280-320)
300
320
340
360
380 400
Figure 7.
WAVELENGTH,nm
Cellulose acetate filtered FSAO lamp spectra and broad band
summation measured with the BARC IRL Spec. D spectroradiometer
at night.
Number 1 indicates a plant position directly under the center of
the fixture. Number 10 indicates a plant position 212 cm from
number 1 and in the same plane as number 1.
14
-------
E
c
CJ
UJ
o
CC
cc
25
20
E 15
10
5
4
3
2
I
Q
LAMP STUDY:
CELLULOSE ACETATE (CA)
MYLAR(M)
CA 365 nm PEAK
M 365 nm PEAK
JL . , ,
o o o o o o o
00 O 04
-------
consisting of lamps filtered with cellulose acetate, lamps filtered with
Mylar and lamp reflectors without lamps. Each plot was split into sub-
plots of UV-B irradiance levels and/or position depending on the distance
of the subplot from the lamps or reflectors. There were two replications
of each of the three treatments for each of the four species. Regression
analyses were performed on the interaction means when the interaction was
found significant at the 5% level of probability.
Potato tubers were planted on June 6, wheat on June 18, radish and
peas on June 29. Tuber "seed" consisted of whole potatoes each of which
weighed 55 g - 5 g. Containers were moved under lamp or exclusion struc-
tures just prior to emergence which occurred for all species during the
last week of June and the first week in July. Duration of exposure and
parameters measured are in the appendix. Over 15,000 individual plant
measurements were made, including 71 parameters. The last plant observa-
tions were made on August 13. A diagram of the entire plot area is in
Figure 9.
RESULTS AND DISCUSSION
Exclusion Study - The solar UV-B spectra of Beltsville (BARC) at 31 m
elevation and the Colorado 3000 m site are compared in Figure 10. There was
a marked increase in irradiance over the entire UV-B range in Colorado re-
lative to Beltsville. These preliminary sepctra suggest that the Colorado
site compared to the Beltsville site may have 2.7 times more biologically
effective UV-B radiation. The weighted irradiance values were 8.3 and
3.1 mW/M for Colorado and Beltsville, respectively. If these high UV-B
16
-------
EXCLUSION STUDY
SNOWMASS 3000m.
KEY
1 /<--
!iC>
^~
\
f*ec*
TMCATVCNT hUwaCA
o
/ ป
IJ
I I
l-J
LAMP STUDY
SNOWMASS 3000m.
f'f
^^ '
it i i '
l~J
( TMl MtnJCATKW KKMTC nKM TNC M5ION t
KEY
S
3
Figure 9. Experimental area depicting lamp and exclusion structure positioning at 3000 m
elevation.
-------
radiation levels can be verified in planned future study then exclusion
experiments employing filters like cellulose acetate, Mylar and Aclar can
easily be used to simulate 20% reductions in stratospheric ozone for low
elevation regions.
In the exclusion study comparisons between cellulose acetate, Aclar
and Mylar were made. In such an experiment effects which are to be att-
ributed to UV-B radiation must be evident under cellulose acetate and Aclar
filtration where natural UV-B radiation is present. Such UV-B radiation
effects should not appear under Mylar filtration where no UV-B radiation
was present. The only result showing a difference between the two types
of filter treatments which could be attributed to UV-B radiation was
wheat plant height indicated in Figure 11. All other measurements on
wheat and other crops showed no significant difference attributable to
UV-B radiation level. In general, sample homogeniety was good with little
variability yet there was little detectable difference among the three
filter treatments whether attributable to UV-B radiation or not (see
appendix for more detail on other crops and parameters). Note that wheat,
having increased UV-B radiation under cellulose acetate or Aclar, tended
to be shorter in stature relative to the zero UV-B radiation control
plants under Mylar. This effect was observed only in the wheat growth at
14 and 31 days. Mixed results not wholly attributable to UV-B radiation
level were obtained after 50 days. Comparison of open and 26% shade treat-
ments also showed a relative stunting of growth in the open for whe"at.
This effect was clear throughout the growth of the plants Figure 12.
18
-------
1000
100-
c
M
I
UJ
o
z:
tr
or
COLORADO, 3000m, 39ฐ II' N
/ /< BELLTSVILLE,3lm,39ฐOrN
0.001
290
300 310
WAVELENGTH , nm
320 330
IRL ARS USDA
19
-------
EXCLUSION STUDY
WHEAT PLANT HEIGHT (cm)
^
HEIGHT
H
-J
Q.
48
47
46
45
t
30
29
28
<
19
18
17
16
DAYS FROM EMERGENCE 50
^
I
I ' I
* 31
I
- I I
* 14
I
- I I
\ 1 1
CA AC M
TREATMENT
Figure 11. Wheat plant height as a function of UV-B exclusion (M = Mylar)
and UV-B transmission (CA = cellulose acetate and AC = Aclar).
20
-------
EXCLUSION STUDY
WHEAT PLANT HEIGHT (cm)
"e
o
1-
o
UJ
z
PLANT
45
44
43
42
31
30
29
28
27
18
17
16
15
14
DAYS FROM EMERGENCE 50
" I
I
* 31
-
I
" I
' 14
I
H*
I
OPEN SHADED
TREATMENT
Figure 12. Wheat plant height in the open relative to 26% shade
equivalent to sea level insolation.
21
-------
However, again these results are unique to the wheat and were not obtained
for the other species. Such results may be attributable to stunting
effects of the extra UV-B radiation in the open; however, the differences
are small. Of the many measurements made, no significant differences
could be found with the other crop species.
A major confounding factor in exclusion studies such as these is
caused by temperature differences under the different filters or shade
treatments. Such temperature differences can cause plant changes which
might be misinterpreted to be UV-B radiation effects. Therefore, careful
temperature measurements were made and the summarized results are in
TABLE 2 (more detailed results are in the appendix TABLE A-l). The aver-
age daytime temperatures of plants under 26% shade was slightly lower dur-
ing the day but also slightly warmer at night. The average daytime temp-
peratures of the plants under Aclar and cellulose acetate filtration (the
UV-B radiation transmitters) were slightly lower than the plant tempera-
tures under Mylar filtration. Otherwise the temperatures were generally
similar. The total solar radiation levels under the three filter treat-
ments, open and shade are in TABLE 2. Note that under the filter treat-
ments the total radiation level is between 90 and 100% of the open control.
Aclar is the best transmitter. Note also that these filters must be effec-
tive transmitters of the long wavelength radiation which normally accounts
for 50% of the total solar radiation. The solar spectra under the three
filters are Figures 4 and 5. They indicate that the UV-B transmission of
cellulose acetate and Aclar is essentially the same from 280 to 750 nm
22
-------
and that the Mylar cuts out the UV-B and reduces the visible radiation
to some extent.
Lamp study - As a general statement there was very little or no
response of plants growing under lamps generating UV-B radiation. Certain
sets of data are selected to illustrate this lack of response in the wheat
2
lamp study (Figures 13 and 14). Note for example, at 204 mW/m (unweight-
ed between 280 and 320 nm) in Figures 13 and 14 there was no difference in
wheat foliage dry weight or plant height throughout the observation period.
For potato foliage dry weight there was no dependence on UV-B radiation
level (Figure 15). In fact, the only effect observed was with the no
lamp control treatment which showed less dry weight production under the
positions that would have had higher irradiation of lamps had they been
present! Other examples of no or small effects can be found in the appen-
dix tables (note particularly TABLES WL-2 and PL-5). In any case the
effect is small. The only visible symptoms of UV-B radiation injury were
observed for radish when the cellulose acetate filters were removed from
the lamps and the plants were irradiated with strong 254 nm radiation. In
such radish plants cotyledon folding was observed soon after emergence.
The above results lead one to suspect that our lamps did not give
enough UV-B irradiation to constitute a 40% enhancement of UV-B radiation.
A number of studies were conducted to check this point. Figure 7 shows
the lamp irradiance with cellulose acetate filtration at various plant
positions under the lamps. The results shows that a gradation of irra-
diance (including UV-B radiation) was present and the radiation level
23
-------
O>
UJ
LU
ฃ
LAMP STUDY-WHEAT DRY WEIGHT (g)
SUPPLEMENTAL UV
204 mW/m2 (280-320 nm)
1.89 mW/m2 (weighted)
= CELLULOSE ACETATE (CA)
* = MYLAR CONTROL (M)
Qa NON LAMP CONTROL (NL)
i i i
30
DAYS FROM EMERGENCE
48
Figure 13. Comparison of the three lamp treatment responses with broad band UV-B irradiance held
constant. Dry weights are the sum of the two plants.
-------
Ul
45
40
35
1 30
u
:c 25
20
3
Q.
10
5
0
LAMP STUDY-WHEAT PLANT HEIGHT (cm)
SUPPLEMENTAL UV
204 mW/m2 (290-320 nm)
1.89 mW/m2 (weighted)
ซ=CELLULOSE ACETATE (CA)
* = MYLAR CONTROL (M)
CUNON LAMP CONTROL (NL)
12
30
DAYS FROM EMERGENCE
48
Figure 14. Comparison of the three lamp treatments responses with broad band UV-B irradiance held
constant.
-------
N)
25
94
iRRADIANCE ,mW-m2 (280-320 nm)
170 204 385
lOr
9
8
o>
*ซ*
i
>-
Q ^
LU
I I I
LAMP STUDY - POTATO FOLIAGE
= CELLULOSE ACETATE (CA)
A* MYLAR CONTROL (M)
0*NON LAMP CONTROL (NL)
0.23 0.88 1.59 1.89
IRRADIANCE mW- m*ป (weighted)
3.57
478
4.34
Figure 15. Comparison of interaction means fitted to linear models, 294 hrs lamp exposure during
49 days.
-------
decreased with increasing diagonal distance from the lamps. The irra-
diation magnitude observed is also the expected magnitude to cause at
least a 40% UV-B radiation enhancement (more probably a 160% enhancement
directly under the lamps). In Figure 8 the cellulose acetate and Mylar
filtered FS40 lamp spectra are presented for the highest plant irradiation
position under the lamps. Note the general absence of radiation in the
UV-A-PAR region (320-700 nm). Based on this it seems unlikely the lamps
should induce additional photoreactivation etc. in the irradiated plants.
However, compare the Colorado solar (natural) UV-B spectrum with the lamp
spectra, i.e. compare Figure 5 with Figure 7. Such preliminary data
suggests that the UV-B irradiance from the sun is overwhelming. Consid-
erably more study at high elevation will have to be conducted.
There was an additional complicating factor in these lamp studies.
Regardless of treatment there was a growth effect that could be detected
under the lamp fixtures which was probably caused by the fixture micro-
climate. For example in wheat it was evident after the first set of ob-
servations taken 14 days after emergence that plant height was a function
of position under the lamp fixtures Figure 16 . Figure 16 presents re-
gression lines as a result of least squares fit to a "power" model. The
power model accounted for 71%, 16%, and 60% of the variability in wheat
height with regard to "unlit" (non-lamp), cellulose acetate, and Mylar
2
filtered lamps, respectively. A linear model gave a somewhat higher R
for the UV-B transmitter, cellulose acetate. However, in either case the
relationship between plant height and diagonal distance was negative
27
-------
(inverse) while plant height and UV-B irradiance was positive, i.e.
better growth in the positions subject to higher UV-B radiation. In any
case, the effect illustrated in Figure 16 is very small. Since this
occurred under all three treatments, the effect might be due to the pro-
tection of the centrally located plants from the primary UV-B source,
the sun.
28
-------
15.5
E 15.0
o
ป
I-
X
ง 14.5
x
ป-
- FS40 LAMP AND CAJRRADIANCE AND PLANT LOCATION
CELLULOSE ACETATE(CA)
MYLAR
UNLIT
to
VO
Q.
<
LJ
X
14.0
13.5
13.0
478
t
IRRADIANCE, mW-m~2(280-320nm)
385 204 170 94
H
4725
iH:
42 92 113 141 184212
DIAGONAL DISTANCE FROM LAMP CENTER, cm
Figure 16. Wheat plant height as a function of diagonal distance from center of lamp fixtures
(plant plane) and irradiance. Measurements made with the IRL Spec. D, spectroradiometer
at night.
-------
Of the 71 parameters evaluated in our two field studies including over
15,000 measurements on four crop species, only suppression of wheat vertical
growth in exclusion studies could be considered a real response to solar
UV-B irradiance level that corresponds to a stratospheric ozone depletion
of 20%. Economic concern based Ion this study seems unwarranted. Indeed
"short stem" wheat is popular and has constituted part of the "green revo-
lution" popular in some areas of the globe.
The lamp study was carried out using a similar field procedure to that
described by Sisson and Caldwell (1975) in that solar irradiance was
supplemented when the solar altitude exceeded 40 ; Figure 2. During this
period the sun would contribute greater than 80% of each days's UV-B
irradiance (Caldwell, 1968). As it happened no clear cut response was noted
in this study. Explanations might include the fact that biologically
effective solar UV-B was overwhelming (Figure 2) relative to biologically
effective lamp UV-B. Another explanation is that some microclimate (such as
shading) under the lamp fixtures protected the plants and counteracted the
adverse effect of UV-B radiation. Also the high UV-A-PAR radiation typical
of this high elevation site may have contributed to strong photoreactivation
or provided other means of repair of UV-B radiation damage. Another factor
possibly having some bearing on the outcome of the lamp study may be the fact
that the 4 crop species employed are considered cool season species and may
be in some way resistant to UV-B injury. Cotton a decidedly warm season
crop appears sensitive to UV-B injury at least in the seedling stage of
30
-------
growth (Krizek 1975, Cams and Christiansen 1975).
No visual evidence such as lesions (Caldwell, 1968), browning (Moore,
1971), red pigmentation, glazing or leaf curviture (Caldwell, 1971) was
noted with regard to any of the four species studied in this test. Particu-
_2
lar attention was paid to the center lamp position (4.34 mW.m ) lamp con-
_o
tribution at 280-320 nm and the open treatment (8.28 mW.m ) at 280-320 nm.
The preceeding are weighted values related to UV-B Beltsville Sun
Equivalents.
31
-------
REFERENCES
Becker, G. F. and J.S. Boyd. (1957). Solar Energy ^ 13.
Caldwell, M. M. (1971). In "Photophysiology" (Edited by A.C. Giese),
Vol. 6, pp. 131-177. Academic Press, New York.
Caldwell, M. M. (1968). Ecol. Monogr. 38 253.
Cams, H. R. and M. N. Christiansen (1975). "Influence of UV-B Radiation
on Abscission - Climatic Impact Assessment Program (CIAP)", Monograph
V. U. S. Department of Transportation, Washington, D. C. In Press.
Cline, M. G. and F. B. Salisbury. (1966). Radiation Botany 6^ 151.
Ergashev A. et al. (1971). Chem abstr. 76. 270 (138308 g).
Kollar, L. R. (1965). "Ultraviolet Radiation". John Wiley and Sons, N. Y.
Krizek, D. T. (1975). Physiol. Plant. 34^ 182.
Moore III, F. D. (1971). CSU-FIC Grant Report, No. 535.
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21 453.
Tousey, R. (1966). In "The Middle UV: It's Science and Technology"
(A. E. S. Green, ed.) p. 1 Wiley, New York.
32
-------
BIBLIOGRAPHY
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Bener, P. (1972). U.S. Army Contract DAJA37-68C-1017, Final Tech. Rept.
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Caldwell, M. M. (1971). Photophysiology ฃ 131.
Campbell, W. F. et al. (1975). Hort Science 10 Abstr. No. 222.
Council on Environmental Quality and Federal Council for Science
and Technology. (1975). "Fluorocarbons and the Environment".
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Dexter, S. F., W. E. Totingham, and L. F. Braber. (1952). Plant Physiol. 7^63.
Dexter, S. T., (1965). Advances in Agronomy, j^ 203.
Garber, M. P. and P. L. Steponkus. (1976a). Plant Physiol. 57 681.
Garber, M. P. and P. L. Steponkus. (1976b). Plant Physiol. 57 673.
Gates, D. M. and R. Janke. (1966). Oecol. Plant. I 39.
Green, A. E. S., T. Sawada, and E. P. Shettle. (1974). Photochemistry and
Photobiology 19^ 251.
Griggs, M. (1966). In Green, A. E. S. "The Middle UV", Wiley, N.Y. 83.
Hudson, R. D. Ed (1972). NASA Ref. Publication 1010, Sci and Tech Information
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Jagger, J. 1958. Bacterial Rev. 22, 99.
Jagger, J. (1967). "Ultraviolet Photobiology". Prentice-Hall, New Jersey.
Levitt, J. (1972). "Responses of Plants to Environmental Stresses".
Academic Press, New York.
Moore III, F. D. (1970). 51st Meeting PD-AAAS Abstr. No. 16
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Rice Nien Dak Sze, H. (1976), Doc P-2123 Executive Summary, C.F. Kettering
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Setlow, R. B. and E. C. Pollard, (1962). Molecular Biophysics. Addison-
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Shettle, E. P. and O.E.S. Green (1974). Applied optics 13 (7) 1567.
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Sisson, W, B, and M. M. Caldwell. (1976). Plant Physiology 58 563.
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Stair, R. (1949). U.S. Dept. of Commerce. N.B.S. RP 2022, 43 209.
Strong, J. (1938). Proceedures in Experimental Physics" Prentice-Hall,
Sukumaran, N.P., and C.J. Weiser, (1972). An excised leaflet test for
evaluating potato frost tolerance. Hort Science. T_ 467.
Van, T.K., L.A. Garrard, and S.H. West. (1976). Crop Science 16 715.
Wellmann, C. (1976). Photochemistry and Photobiology 24 659.
Zimmerman, A. P. and L. E. Campbell. (1970). Amer. Soc. Agri. Eng.
Paper No. 70-342.
34
-------
APPENDIX
Various experiments were conducted which were preliminary or provide addi-
tional technical information. Such results are collected here without detailed
analysis. Results collected include:
1) The spectrum of Aclar(Figure Al)
2) The UV-B radiation output from FS40 lamps filtered with cellulose
acetate as a function of time energized and lamp temperature
(Figure A-2 and A-3).
3) A potential solar UV-B collector and irradiator which could be used
to enhance solar UV-B radiation without the use of filtered lamps
(Figure A-4).
4) Detailed temperature analysis for plants in exclusion study (TABLE
A-l).
5) Preliminary results for wheat leaf viability tests for UV-B irradiated
leaves. The test involved the use of elctrolyte leakage as a measure
of leaf tissue cell lysis (TABLE A-2).
6) Tabulated technical data for exclusion studies on wheat, potato, and
radish (TABLES WE-1; PE-1; RE-1).
7) Tabulated technical data for various FS40 lamp irradiations on wheat
(TABLES WL-1 to WL-5). potato (TABLES PL-1 to PL-6), radish (TABLES
RL-1 to RL-6). and pea (TABLES PEL-1 to PEL-3).
Information developed during our studies would indicate that perhaps
cellulose acetate should be solarized 8 hours prior to use as FS40 lamp
filters. Since lamp output begins to decline at 6 C ambient temperature,
35
-------
the mountain researcher should measure UV-B irradiance in situ at the
beginning and end of the illumination period. Fortunately, in our lamp
study, temperatures were above 6 C at the beginning and end of the illumina-
tion period. Aclar appears to be a good "window" for use in exclusion
studies, however, 1.5 mil film used in our studies does not have a comfortable
safety margin with regard to tearing. Five mil material is suggested.
36
-------
100
90
80
j5 70
Z 60
O
(/}
to 50
40
tr
I- 30
20
10
0
ACLAR^ 22A-5MIL.
7 of 2 spectra
j I
_L L
I
till
1
i i i i
j i
j i
200 220 240 260 280 300 320
400 500
WAVELENGTH,nm
600
700
Figure A-l. Laboratory spectra developed with Perkin and Elmer spectrophotometer. Aclar is a flexible
thermoplastic film manufactured by Allied Chemical Corporation from fluorinated-chlorinated
resins.
-------
00
E
c
O
ro 6
O
oo
ou
CVJ
E
55
UJ
o
9=
O
UJ
LJ
- 5
UV-B OUTPUT, 4 FS40 CA FILTERED LAMPS
2 4
HOURS ENERGIZED
8 10
HOURS ENERGIZED
12
Figure A-2.
Variability in broad band UV-B irradiance for 2, 6 hour periods including 7, 4-lamp sets,
Prior to the test lamps were operated for 100 hrs. and cellulose acetate was solarized
for 6 hrs.
-------
vo
0.7-
Lamps were operated for approximately 200 hours prior to test.
A G.E. "214S ultraviolet meter" was used.
1.0-
0.9-
Position of
Detector
Left
(20 cm from
end)
Center
Right
(20 cm from
end)
Distance from Lamp
0 cm
10 cm
D
O
Q
0.6-
meter reading at T
maximum meter reading
obtained (200 units)
0.5 -
Ot
10
15
Relative Intensity Output, f, of FS40 Lamp
as a Function of Temperature, T (ฐC). A
Reflector was not used. Only points for
lamp center measurements are connected.
20 T(eC)
Figure A-3.
-------
SOLAR UV-B COLLECTOR AND IRRADIATOR
CSU HORTICULTURE, F.D.MOORE 9/19/77
E
riwwซ-*i *
(adjustable atenuator) (
CIRCULATING
. COOLING
WATER
ATENUATION OF UV-A AND PAR-
r 280-320 nm
^ 320 cutoff
NiS04 ปCoSCU
(aqueous solution)
UV-B SENSOR
UV-A PAR SENSORS
STEEL
IEFLECTOR
PIVOT
Figure A-4. Design of a potential solar UV-B research tool.
-------
TABLE A-l. EXCLUSION STUDY: AIR, PLANT, AND NATIVE SOIL TEMPERATURES,
POTATO1
Solar filter
max
None (open) mean
min
max
Cellulose acetate mean
min
max
Aclar mean
min
max
Mylar mean
min
max
Shade mean
min
24 hr mean temperatures ( C)
air
20.8
12.9
5.5
21.8
13.6
6.0
20.6 121. 20J2
12T9~|13.25I
21.3
13.1
5.8
21.1
12.7
5.4
plant
19.0
12.7
7.0
19.8
14.1
8.5
14.2 HO
8.3 [8.401
21.5
14.3
8.3
18.0
12.7
7.5
soil
24.5
16.2
8.0
30.5
18.8
10.5
28. 0129.251 .
9.8 [10 TlV)
29.5
18.9
10.5
24.5
16.0
9.0
Temperatures were measured continuously for a period of one hour every
third hour (8 times for each of two 24 hr periods).
Precision is + n ,or
~ U. ^t Lป.
2
Values in boxes are means of both UV-B transmitters to be
compared with Mylar.
41
-------
1 2
TABLE A-2. RELATIVE WHEAT LEAF ELECTROLYTE LEAKAGE '
Evaluation Samples showing Samples appearing
visual injury healthy
(% electrolytes leaked) (% electrolytes leaked)
1
2
3
4
5
6
mean
29
17
57
32
27
31
32
56
13
12
37
13
21
25
1. Results in the two columns were not significantly different at even
the 10% level (unpaired t test).
2. Relative electrolyte leakage was x = 7- 1.5% standard deviation.
42
-------
TABLE WE-1. MEANS AND MEAN SQUARES FROM EXCLUSION EXPERIMENT, WHEAT
FRESH
WT
Exposure (hrs, days) 186,31
Units
Open
Shade
CA
AC
M (-UVB)
Treatment
MS
df
Error
MS
df
Total observation
Observations/x
g
3.8831
3.97a
3.58b
3.58b
3.78ab
2.98**
4
0.81
465
480
96
DRY WT
186,31
g
0.71
0.67
0.79
0.66
0.72
0.008
4
0.011
8
15
3
FRESH
WT DRY WT
300,50 300,50
g
8.30
8.30
8.26
8.28
8.07
0.472
4
1.895
225
240
48
g
2.49
2.39
2.46
2.42
2.42
0.004
4
0.021
8
15
3
PLANT
HT
84,14
cm
15. Ic
17. 2b
17. Ob
17. Ob
18. 6a
73.1**
4
1.8
225
240
48
PLANT
HT
186,31
cm
26. 6d
29. 9a
27. 9c
28. Oc
28. 9b
210.5**
4
7.5
705
720
144
PLANT
HT
300,50
cm
42. 8d
44. 6c
46. 4b
47. 3a
46. 3b
304.3**
4
8.2
465
480
96
HEAD
LENGTH
300,50
HEADS
300,50
cm %
1.
1.
3.
2.
3.
138.
4
3.
465
480
96
7c
2c
7a
5b
9a
91**
59
60. Ob
45. 2c
78. Oa
71. 2a
79. 7a
19766.1**
4
942
465
480
96
TILLERS
300,50
no/plant
2.4a
2.0c
2.2b
2.0bc
2. Ob
2.185**
4
0.271
465
480
96
Column means separated by LSD, 5% level. Means followed by
different
the same letter are not significantly
-------
TABLE PE-1. MEANS AND MEAN SQUARES FROM EXCLUSION EXPERIMENT, POTATO
Open
Shade
CA
AC
M(-UVB)
Treatment
MS
df
Error
MS
df
Total
observations
Observations/
X
FOLIAGE
FW
g
67 . Sic1
80.73a
71.59bc
73.70abc
76.22ab
354.00*
4
118.79
60
75
15
FOLIAGE
DW
g
7.35
7.79
7.72
7.62
7.93
0.7192
4
0.8441
60
75
15
TUBER
FW
g
29.54
28.18
29.05
28.44
28.21
188.84
4
123.04
60
75
15
TUBER
DW
g
14.21
14.30
12.12
13.98
14.52
5.309
4
5.746
60
75
15
FW/ TUBER
g
14.21
14.30
12.12
13.98
14.52
14.17
4
20.51
60
75
15
DW/TUBER
g
2.76
2.70
2.41
2.59
2.83
0.3921
4
0.7444
60
75
15
FOL FW/
TUB FW
0.45b
0.54a
0.49ab
O.Sla
0.53a
0.0206**
4
0.0048
60
75
15
FOL DW/
TUB DW
0.25
0.28
0.27
0.27
0.28
0.0029
4
0.0012
60
75
15
TUBER
NO
11.7
11.3
12.7
11.2
11.3
5.626
4
11.679
60
75
15
STEM
NO
8.8
8.3
8.6
8.8
9.1
1.113
4
6.993
60
75
15
TUBERS/
STEM
1.5
1.4
1.5
1.4
1.3
0.1821
4
0.3071
60
75
15
Column means separated by LSD, 5% level. Means followed by the same letter are not significantly
different.
-------
TABLE RE-1. MEANS AND MEAN SQUARES FROM EXCLUSION EXPERIMENT, RADISH.
FOLIAGE FOLIAGE FOLIAGE FOLIAGE ROOT ROOT ROOT
FW DW FW DW FW DW FW
ROOT FOLIAGE
DW FW/ROOT
FW
FOLIAGE FOLIAGE FOLIAGE
DW/ROOT FW/ROOT DW/ROOT
DW FW DW
Exposure
(hrs., days) 144,24 144,24
Units g g
216,36 216,36 144,24 144,24
g
g
g
g
216,36 216,36 144,24
g g g
144,24 216,36 216,36
g g g
Open
Shade
CA
AC
M(-UVB)
Treatment
MS
df
Error
MS
df
Total
observa-
tions
Observa-
tions/x
2.80a
2.47b
2.71ab
2.61ab
2.86a
0.9881*
4
0.3884
195
210
42
0.35
0.28
0.33
0.31
0.35
0.0026
4
0.0009
8
15
3
4.66b
4.20b
5.60a
5.39a
5.44a
15.17**
4
1.7357
195
210
42
0.62b
0.54b
0.79a
0.76a
0.73a
4.34a
3.04b
3.88a
3.83a
4.40a
0.0341**12.48**
4
0.0034
8
15
3
4
2.168
195
210
42
0.29
0.19
0.25
0.23
0.29
0.0056
4
0.0018
8
15
3
11.52b 0.76b
9.18c 0.62c
14.83a 0.95a
14.21a 0.90ab
13.20ab 0.89ab
1.72
1.11
0.76
0.77
0.93
218.6** 0.0537**6.66
4 4
19.8 0.0060
195 8
210 15
42 3
4
7.57
195
210
42
1.22
1.50
1.33
1.48
1.22
0.0573
4
0.0361
8
15
3
0.46
0.50
0.43
0.40
0.44
0.055
4
0.025
195
210
42
0.83
0.88
0.84
0.84
0.83
0.0016
4
0.0085
8
15
3
Column means separated by
different.
LSD, 5% level. Means followed by the same letter are not significantly
-------
TABLE WL-1. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT WHEAT
FOLIAGE, WT, LAMP EXPOSURE 192 HRS DURING 32 DAYS
UVB LAMP IRRADIANCE
Weighted
mW.m
-2
4.34
3.57
,52
.89
.59
.12
2.
1.
1.
1.
0.88
0.65
0.44
0.23
-UVB means
Source
Non-weighted
-2
mW.m
478
385
273
204
170
123
94
85
47
25
df.
FRESH WT
+UVB
CA
g
-UVB
M
g
U
g
DRY WT
+UVB
CA
g
-UVB
M
g
U
g
4.2
3.8
4.2
4.0
3.8
3.8
3.9
3.6
4.1
4.2
3.7
4.0
3.8
4.0
3.8
4.2
4.0
3.6
3.9
4.1
4.2
4.0
4.4
3.8
4.1
4.4
4.1
3.5
3.7
3.7
0.91
0.82
0.85
0.84
0.82
0.84
0.82
0.77
0.89
0.90
0.76
0.85
0.78
0.81
0.80
0.87
0.82
0.75
0.82
0.86
0.92
0.85
0.93
0.83
0.88
0.96
0.80
0.76
0.81
0.81
4.0 3.9 4.0 0.85 0.81 0.85
Mean squares
Fresh wt
Dry wt
- UVB 2
Error a 2
Irradiance 9
Interaction 18
Error b 27
0.20
6.70
1.21
0.73
1.27
Fresh weight total observations, 480; - UVB, 160;
irradiance, 16
Dry weight total observations; 240; - UVB, 80;
irradiance, 8
0.0376
0.1695
0.0289
0.0169
0.0163
46
-------
TABLE WL-2. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT WHEAT
FOLIAGE WT. LAMP EXPOSURE 300 HRS DURING 50 DAYS
UVB LAMP IRRADIANCE
FRESH WT
DRY WT
Weighted Non-weighted
mW.m
4.34
3.57
2.52
-2
1,
1,
1.
89
59
12
0.88
0.65
0.44
0.23
mW.m
478
385
273
204
170
123
94
85
47
25
-2
+UVB
CA
-UVB
M
U
g
+UVB
CA
g
-UVB
M
g
U
g
7.9
8.2
9.0
8.7
9.1
8.5
8.2
9.3
8.8
8.0
8.6
8.2
8.4
9.3
8.6
8.5
8.9
8.3
8.2
8.5
9.0
9.4
9.1
9.3
9.4
9.0
9.6
9.0
8.8
8.6
2.5
2.5
2.8
2.7
2.8
2.6
2.6
2.9
2.7
2.5
2.5
2.6
2.7
2.9
2.9
2.8
2.8
2.6
2.6
2.7
2.8
2.6
2.8
2.9
2.9
2.8
3.0
2.8
2.8
2.7
-UVB means
8.6k 8.61 9.1a 2.7 2.7 2.8
Source
df.
Mean squares
Fresh wt
Dry wt
- UVB
Error a
Irradiance
Interaction
Error b
2
2
9
18
27
8.41** 0.69
1.90 0.27
1.46 0.17
1.05 0.08
0.08 0.01
Fresh weight total observations, 240; - UVB, 80;
irradiance, 8
Dry weight, same
- UVB mean separation (within parameter) by LSD, 5% level.
Means followed by the same letter are not significantly
different.
47
-------
TABLE WL-3. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT WHEAT
PLANT HEIGHT, LAMP EXPOSURE 84 HRS DURING 14 DAYS
AND 192 HRS DURING 32 DAYS
UVB LAMP IRRADIANCE
Weighted
mW.m
-2
4,
3.
2.
1.
1.
1.
34
57
52
89
59
12
0.88
0.65
0.44
0.23
Non-weighted
-2
mW.m
478
385
273
204
170
123
94
85
47
25
PLANT HT (84 hrs)
+UVB -UVB
CA
cm
PLANT HT (186 hrs)
+UVB -UVB
M
cm
U
cm
CA
cm
M
cm
U
cm
14.2
14.2
13.5
14.5
13.4
13.3
14.3
13.0
13.8
13.0
14.3
13.9
13.7
14.0
13.5
13.7
13.5
13.7
13.9
13.5
14.7
13.9
13.4
13.7
13.7
15.5
13.2
13.2
14.0
13.4
27.9
25.8
26.6
26.7
25.2
24.7
25.5
24.8
25.8
24.9
26.6
25.8
26.4
27.8
26.2
26.6
26.4
24.7
24.7
26.2
26.6
25.7
25.2
25.2
26.6
26.4
27.6
24.4
25.5
24.9
-UVB means
Source
df.
13.7 13.8 13.7 25.8 26.1 25.8
Mean squares
Plant ht
Plant ht
- UVB
Error a
Irradiance
Interaction
Error b
2
2
9
18
27
0.28
1.30
3.15*
0.73
1.29
8.56
62.22
34.14
16.01
21.82
Plant height (84 hrs) total observations, 240; - UVB, 80;
irradiance, 8
Plant height (186 hrs) total observations, 720; - UVB, 240;
irradiance 24
48
-------
TABLE WL-4. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENTS WHEAT
PLANT HEIGHT AND HEAD LENGTH, LAMP EXPOSURE 300 HRS
DURING 50 DAYS
UVB LAMP IRRADIANCE
Weighted Non-weighted
-2 -?
mW.m
4.34
3.57
2.52
1.89
1.59
1.12
0.88
0.65
0.44
0.23
- UVB means
Source
- UVB
Error a
Irradiance
Interaction
Error b
mW.m
478
385
273
204
170
123
94
85
47
25
df.
2
2
9
18
27
PLANT HT
+UVB -UVB
CA
cm
42
39
38
39
40
39
39
40
39
36
39
.9
.7
.7
.6
.2
.4
.7
.5
.7
.7
.7
M
cm
40.
40.
39.
41.
41.
40.
39.
38.
39.
38.
40.
7
6
3
4
8
0
1
7
8
9
0
U
cm
42.9
42.1
40.4
41.8
42.3
39.7
41.7
39.9
40.0
39.6
41.0
Plant
76.
67.
55.
12.
13.
HEAD LENGTH
+UVB -UVB
CA
cm
4.
1.
1.
1.
2.
2.
2.
3.
2.
1.
2.
Mean
ht
2
2
7** .
1
9
2
8
9
9
5
1
2
2
4
9
4
M
cm
1.5
2.5
2.2
2.1
2.4
2.8
1.9
2.4
2.2
2.0
2.2
3
2
2
2
2
3
2
2
2
1
2
U
cm
.1
.3
.4
.6
.1
.1
.5
.3
.3
.8
.4
squares
Head
2.
19.
4.
4.
2.
length
46
86
77
72
81
Plant height total observations, 480; - UVB, 160;
irradiance 16
Head length, same
49
-------
TABLE WL-5. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT WHEAT
PLANT HEAD AND TILLER PRODUCTION,
300 HRS DURING 50 DAYS
UVB LAMP
IRRADIANCE
% HEADS
+UVB
Weighted
-2
mW.m
4.34
3.57
2.52
1.89
1.59
1.12
0.88
0.65
0.44
0.23
- UVB means
Non-weighted
-2
mW.m
478
385
273
204
170
123
94
85
47
25
CA
96.
64.
52.
63.
53.
53.
67.
80.
68.
62.
66.
9
6
0
1
1
1
7
2
8
5
2
M
49.
77.
57.
66.
67.
77.
64.
72.
70.
77.
68.
-UVB
0
0
3
7
7
1
6
9
3
1
0
U
79.
77.
66.
75.
71.
69.
78.
64.
72.
67.
72.
2
1
7
0
9
8
1
6
9
7
3
LAMP EXPOSURE
TILLERS /PLANT
+UVB
CA
2.4
2.6
2.8
2.9
2.8
2.7
2.8
2.8
2.8
2.8
2.7
-UVB
M
3.0
2.6
2.6
2.8
2.5
2.8
2.9
2.6
2.7
2.9
2.8
2
2
2
2
2
2
2
2
2
2
2
U
.6
.6
.6
.8
.7
.6
.9
.8
.7
.5
.7
Mean squares
Source df.
- UVB 2
Error a 2
Irradiance 9
Interaction 18
Error b 27
Percent heads total observations, 480; - UVB, 160;
irradiance 16
Tillers per plant, same
% heads
1569.69
4676.56
1083.12
1868.39
1335.25
Tillers/plant
0.2271
0.0521
0.3336
0.3544
0.2956
50
-------
TABLE PL-1. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT
POTATO FOLIAGE WEIGHT, LAMP EXPOSURE 294 HRS
DURING 49 DAYS
UVB LAMP IRRADIANCE
FRESH WT
DRY WT
+UVB
-UVB
+UVB
-UVB
Weighted Non-weighted
-2
-2
mW.m mW.m
4.34 478
3.57 385
1.89 204
1.59 170
0.88 94
0.44 47
0.23 25
- UVB means
Source df.
- UVB 2
Error a 2
Irradiance 6
Interaction 12
Error b 18
Total observations for each parameter, 168; - UVB, 56;
irradiance, 8
CA
g
76.
69.
71.
63.
63.
66.
67.
68.
4
4
0
3
9
7
5
3
M
g
72.
67.
66.
69.
64.
61.
64.
66.
9
2
6
0
0
9
5
6
U
g
52.
65.
66.
67.
65.
64.
61.
63.
CA
4
4
2
5
2
8
4
3
7
7
7
6
6
7
7
7
Mean
g
.4
.1
.4
.6
.9
.1
.0
.1
7
7
6
6
6
6
6
6
M
g
.0
.1
.9
.9
.7
.8
.9
.9
5
6
6
6
6
6
6
6
U
g
.5
.7
.7
.9
.9
.7
.5
.6
squares
Fresh wt
366
281
59
211
51
t r c\ _
.706
.841
.096
Dry
.476**
.590
+ ,.
ซ%
r- x
3.
1.
0.
1.
0.
wt
509
219
391
202*
385
51
-------
TABLE PL-2. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT
POTATO TUBER WEIGHT PER PLANT, LAMP EXPOSURE
294 HRS DURING 49 DAYS
UVB LAMP IRRADIANCE
Weighted
FRESH WT
mW.m
-2
DRY WT
4.34
3.57
.89
.59
0.88
0.44
0.23
1.
1.
HJVB
Non-weighted CA
-2
mW.m
478
385
204
170
94
47
25
g
142
153
155
147
153
155
150
.6
.8
.9
.1
.6
.4
.2
M
g
157.
151.
152.
148.
152.
147.
152.
-UVB
9
3
1
7
7
9
1
U
g
132
143
146
152
144
152
138
.3
.0
.9
.4
.4
.7
.'7
+UVB
CA
g
28
31
31
29
30
30
29
.0
.0
.4
,6
.2
.8
.3
-UVB
M
g
31.
29.
30.
29.
30.
28.
29.
0
6
5
2
3
9
6
U
g
25.8
28.5
29.1
30.0
27.2
29.5
26.8
- UVB means
Source
df.
151.2 151.8 144.3 30.0 29.9 28.1
Mean squares
Fresh wt
Dry wt
- UVB 2
Error a 2
Irradiance 6
Interaction 12
Error b 18
965.072
1021.540
175.058
264.649
208.740
Total observations for each parameter, 168;
- UVB 56; irradiance, 8
62.7935
41.8899
12.3421
2.3623
10.7601
52
-------
TABLE PL-3. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENTS
POTATO TUBER WEIGHT PER TUBER, LAMP EXPOSURE
294 HRS DURING 49 DAYS
UVB LAMP IRRADIANCE
Weighted Non-weighted
mW.m
4,
3.
1,
1.
34
57
89
59
0.88
0.44
0,23
- UVB means
Source
UVB
Error a
Irradiance
Interaction
Error b
mW.m
478
385
204
170
94
47
25
-2
df.
2
2
6
12
18
FRESH WT
DRY WT
+UVB
-UVB
+UVB
-UVB
CA
g
9.3
11.3
10.8
10.8
13.0
13.3
11.8
11.5
M
g
11.7
10.7
10.1
11.0
9.9
13.0
11.3
11.1
U
g
15.3
10.5
11.0
13.0
15.1
13.2
11.5
12.8
CA
g
1.8
2.3
2.2
2.2
2.5
2.6
2.3
2.3
M U
g g
2.3 3.0
2.1 2.1
2.0 2.2
2.2 2.6
2.0 3.3
2.5 2.7
2.2 2.2
2.2 2.6
Mean squares
Fresh
45
7
19
16
10
wt
.13
.62
.93
.30
.46
Dry wt
2.0943
0.5071
0.8593
0.8507
0.5015
Total observations for each parameter, 168; - UVB 56;
irradiance, 8
53
-------
TABLE PL-4. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT
POTATO FOLIAGE WEIGHT PER TUBER WEIGHT, LAMP
EXPOSURE 294 HRS DURING 49 DAYS
UVB LAMP IRRADIANCE
Weighted
mW.m
4.34
3.57
1.89
1.59
0.88
0.44
0.23
-2
Non-weighted
mW.m
478
385
204
170
94
47
25
FRESH WT(ratio)
+UVB -UVB
CA
DRY WT(ratio)
+UVB -UVB
M
U
CA
M
U
0.54
0.45
0.46
0.43
0.42
0.43
0.45
0.46
0.45
0.44
0.46
0.42
0.42
0.42
0.40
0.46
0.45
0.44
0.45
0.42
0.44
0.27
0.23
0.24
0.22
0.23
0.23
0.24
0.22
0.24
0.23
0.24
0.22
0.23
0.23
0.21
0.24
0.23
0.23
0.26
0.23
0.24
- UVB means
Source
df.
0.45 0.44 0.44 0.24 0.23 0.23
Mean squares
Fresh wt Dry wt
- UVB 2
Error a 2
Irradiance 6
Interaction 12
Error b 18
0.0043
0.0013
0.0051
0.0082**
0.0024
0.0005
0.0005
0.0003
0.0002
0.0010
Total observations for each parameter, 168; - UVB 56;
irradiance, 8
54
-------
TABLE PL-5. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
POTATO TUBER NUMBER AND STEM NUMBER, LAMP
EXPOSURE 294 HRS DURING 49 DAYS
UVB LAMP IRRADIANCE
Weighted Non-weighted
mW.m
-2
4,
3,
1.
1.
34
57
89
59
0.88
0.44
0.23
mW.m
478
385
204
170
94
47
25
-2
TUBER NO.
+UVB -UVB
CA M U
STEM NO.
+UVB -UVB
CA
M
U
15.3
13.8
14.8
14.9
12.4
12.1
13.4
13.8
15.0
15.4
14.8
15.9
12.3
14.9
9.3
14.1
14.0
13.0
9.9
12.1
12.5
9.3
9.3
8.5
13.8
7.9
8.5
8.1
10.8
10.3
8.6
10.6
9.4
9.1
10.9
7.5
9.3
8.8
7.1
7.4
7.0
9.1
- UVB means
13.8 14.6 12.1,
a a b
9.3
9.9 8.0
Source
df.
Mean squares
Tuber no.
Stem no.
- UVB 2
Error a 2
Irradiance 6
Interaction 12
Error b 18
86.8218*
2.1790
22.5198
15.1920
14.0247
54.0576
13.0779
16.5258
15.1944
26.2596
Total observations for each parameter, 168;
- UVB 56; irradiance, 8
- UVB mean separation (within parameter) by LSD, 5% level.
Means followed by the same letter are not significantly
different.
55
-------
TABLE PL-6. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
NUMBER OF POTATO TUBERS PER STEM, LAMP
EXPOSURE 294 HRS DURING 49 DAYS
UVB IRRADIANCE
TUBERS/STEM
Weighted Non-weighted
-2
mW.m mW.m
4.34 478
3.57 385
1.89 204
1.59 170
0.88 94
0.44 47
0.23 25
- UVB means
Source df.
- UVB 2
Error a 2
Irradiance 6
Interaction 12
Error b 18
-2
+UVB -UVB
CA M
1.7 1.3
1.6 1.5
1.8 1.8
1.7 1.4
1.6 1.7
1.5 1.4
1.8 1.4
r
1.71 1.5.
a b
Mean squares
Tubers/stem
0.3157**
0.0010
0.2564
0.3060*
0.1369
U
1.2
1.6
1.6
1.9
1.5
1.9
1.4
1.6
a
Total observations for each parameter, 168;
- UVB 56; irradiance 8
- UVB means separation (within parameter) by LSD 5% level.
Means followed by the same letter are not significantly
different.
56
-------
TABLE RL-1. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
RAnTSH FOLIAGE WEIGHT, LAMP EXPOSURE 144 HRS
DURING 24 DAYS
UVB LAMP IRRADIANCE
FRESH WT
DRY WT
Weighted Non-weighted
mW.m
-2
4.34
3.57
52
89
59
12
0.88
0.65
0.44
0.23
- UVB means
Source
- UVB
Error a
Irradiance
Interaction
Error b
mW.tn
478
385
273
204
170
123
94
85
47
25
-2
df.
2
2
9
18
27
4-UVB
2
1
2
1
2
2
2
2
2
2
2
CA
g
.19
.87
.04
.97
.25
.35
.25
.26
.63
.42
.23
2
2
1
2
1
1
1
2
2
2
2
-UVB
M
g
.63
.20
.92
.00
.93
.98
.86
.09
.08
.18
.09
2
2
2
2
2
2
2
2
1
2
2
U
g
.59
.38
.39
.28
.47
.28
.30
.29
.98
.09
.30
+UVB
0
0
0
0
0
0
0
0
0
0
0
Mean
CA
g
.24
.23
.24
.23
.26
.30
.27
.28
.32
.29
.27
-UVB
M
g
0.
0.
0.
,31
,26
23
0.24
0.
0.
0.
0.
0.
0.
0.
22
23
22
24
24
26
25
0
0
0
0
0
0
0
0
0
0
0
U
g
.29
.28
.27
.30
.29
.28
.29
.29
.25
.25
.28
squares
Fresh wt
0.97
0.71
0.27
0.38
0.25
Dry wt
0.
0.
0.
0.
0.
0216
0167
0025
0068
0044
Total observations for each parameter, 240;
- UVB, 80; irradiance, 8
57
-------
Mซ* ปKM'Witt..
TABLE RL-2. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT
RADISH FOLIAGE WEIGHT, LAMP EXPOSURE 168 HRS
DURING 28 DAYS
UVB LAMP IRRADIANCE
FRESH WT
DRY WT
Weighted
mW.m
-2
4,
3,
2,
1.
1.
1.
34
57
52
89
59
12
0.88
0.65
0.44
0.23
Non-weighted
-2
mW.m
478
385
273
204
170
123
94
85
47
25
+UVB
CA
g
-UVB
M
g
U
+UVB
CA
-UVB
M
U
g
3.49
2.85
2.78
3.56
3.54
3.33
2.70
3.03
3.02
3.36
2.98
2.63
2.67
2.96
2.26
2.11
2.90
2.81
3.00
2.97
3.22
3.22
3.18
3.47
2.75
3.13
3.19
3.23
2.94
3.37
0.35
0.29
0.26
0.32
0.34
0.33
0.31
0.32
0.32
0.33
0.28
0.29
0.25
0.29
0.23
0.33
0.28
0.27
0.30
0.31
0.36
0.39
0.38
0.40
0.32
0.38
0.39
0.37
0.36
0.40
- UVB means
3.17 2.83 3.17
0.32 0.28 0.38
Source
df.
Mean squares
Fresh wt
Dry wt
- UVB 2
Error a 2
Irradiance 9
Interaction 18
Error b 27
3.08
2.06
0.73
0.48
0.25
Total observations for each parameter, 240;
- UVB, 80; irradiance, 8
0.1718
0.0638
0.0068
0.0041
0.0039
58
-------
TABLE RL-3. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
RADISH ROOT WEIGHT, LAMP EXPOSURE 144 HRS
DURING 24 DAYS
UVB LAMP IRRADIANCE
FRESH WT
DRY WT
+UVB
-UVB
+UVB
-UVB
Weighted Non-weighted
tnW.m
-2
4.34
3.57
.52
.89
.59
,12
2.
1.
1.
1.
0.88
0.65
0.44
0.23
mW.m
478
385
273
204
170
123
94
85
47
25
-2
CA
g
3.27
2.56
3.11
3.01
3.93
3.53
2.82
3.21
3.17
3.99
M
g
4.10
3.29
2.24
2.99
2.84
2.87
2.77
2.86
2.74
2.96
U
g
4.20
3.54
4.18
3.62
4.01
3.87
3.49
3.04
4.21
3.28
CA
g
0.19
0.15
0.18
0.17
0.23
0.21
0.17
0.20
0.19
0.24
M
g
0.24
0.20
0.14
0.19
0.18
0.19
0.20
0.19
0.18
0.18
U
g
0.26
0.23
0.25
0.23
0.25
0.24
0.22
0.20
0.25
0.21
- UVB means
3.26 2.97 3.74
0.19 0.19 0.23
Mean squares
Source df.
- UVB 2
Error a 2
Irradiance 9
Interaction 18
Error b 27
Fresh wt
12.30
10.20
1.66
1.57
2.14
Dry wt
0.0429
0.0393
0.0044
0,0048
0.0066
Total observations for each parameter, 240;
- UVB, 80; irradiance, 8
59
-------
TABLE RL-4. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
RADISH ROOT WEIGHT, LAMP EXPOSURE 168 HRS
DURING 28 DAYS
UVB LAMP IRRADIANCE
FRESH
+UVB
Weighted Non-weighted
-2 -">
mW.m
4.34
3.57
2.52
1.89
1.59
1.12
0.88
0.65
0.44
0.23
- UVB means
mW.m
478
385
273
204
170
123
94
85
47
25
6
4
5
6
6
5
5
5
5
5
5
CA
g
.23
.70
.57
.50
.28
.92
.70
.07
.59
.41
.70
6
4
4
5
4
4
5
5
4
4
5
WT
-UVB
M
g
.10
.47
.72
.47
.40
.91
.61
.49
.84
.51
.05
8
5
6
4
6
6
6
5
5
6
6
U
g
.11
.72
.61
.67
.00
.26
.42
.45
.99
.06
.13
DRY WT
+UVB -UVB
0
0
0
0
0
0
0
0
0
0
0
Mean
Source
- UVB
Error a
Irradiance
Interaction
Error b
df.
2
2
9
18
27
CA
g
.44
.34
.37
.47
.44
.41
.41
.38
.41
.39
.41
M
g
0.42 0
0.35 0
0.37 0
0.40 0
0.34 0
0.37 0
0.41 0
0.39 0
0.37 0
0.37 0
0.38 0
U
g
.50
.41
.45
.34
.41
.43
.43
.38
.41
.45
.42
squares
Fresh wt
23.51
1.71
5.70
2.86
3.88
Dry wt
0.0369
0.0115
0.0127
0.0096
0.0130
Total observations for each parameter, 240;
- UVB, 80; irradiance, 8
60
-------
JflLJL,
TABLE RL-5. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
RADISH FOLIAGE WT PER ROOT WT, LAMP EXPOSURE
144 HRS DURING 24 DAYS
UVB LAMP IRRADIANCE
+UVB
Weighted Non-weighted
-2 -?
mW.m '
4.34
3.57
2.52
1.89
1.59
1.12
0.88
0.65
0.44
0.23
- UVB means
mW.m
478
385
273
204
170
123
94
85
47
25
1
1
1
1
1
1
2
1
1
1
1
CA
.34
.62
.48
.49
.22
.52
.64
.68
.78
.30
.61
FRESH WT
-UVB
1
1
1
1
2
1
1
1
2
1
1
vr
.47
.58
.81
.47
.14
.24
.50
.62
.29
.46
.66
1
1
1
1
1
1
2
1
1
1
1
U
.16
.58
.11
.56
.51
.94
.28
.45
.99
.79
.64
DRY WT
-HJVB -UVB
0
0
0
0
0
0
1
0
0
0
0
Mean
Source
- UVB
Error a
Irradiance
Interaction
Error b
df.
2
2
9
18
27
CA
.69
.77
.80
.72
.61
.76
.51
.86
.91
.66
.83
M
0.75
0.93
1.04
0.75
1.45
0.72
1.67
1.00
1.66
0.81
1.08
U
0.63
0.92
0.59
0.78
0.84
0.84
1.18
0.76
0.96
0.96
0.85
squares
Fresh wt
1.58
1.83
1.29
0.30
0.64
Dry wt
0.057
1.105
1.522
0.865
1.059
Total observations for each parameter, 240;
- UVB, 80; irradiance, 8
61
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TABLE RL-6. MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
RADISH FOLIAGE WT PER ROOT WT, LAMP EXPOSURE
168 HRS DURING 28 DAYS
UVB LAMP IRRADIANCE
Weighted
mW.m
-2
4.34
3.57
.52
.89
.59
.12
2.
1.
1,
1.
0.88
0.65
0,44
0.23
Non-weighted
-2
mW.m
478
385
273
204
170
123
94
85
47
25
FRESH WT
+UVB
CA
0.57
0.69
0.51
0.63
0.60
0.58
0.58
0.63
0.63
0.70
-UVB
M
0.54
0.65
0.57
0.56
0.58
0.66
0.55
0.55
0.79
0.69
U
0.44
0.57
0.57
0.83
0.51
0.54
0.57
0.60
0.53
0.62
DRY WT
+UVB -UVB
CA
0.81
0.96
0.72
0.75
0.80
0.81
0.95
0.89
0.88
0.88
M
0.69
0.87
0.67
0.75
0.74
0.94
0.70
0.71
0.96
0.86
U
0.73
0.94
0.93
1.23
0.92
0.91
1.01
0.98
0.94
0.98
- UVB means
0.61 0.61 0.58
0.85 0.79 0.96
Source
df.
Mean squares
Fresh wt
Dry wt
- UVB 2
Error a 2
Irradiance 9
Interaction 18
Error b 27
0.032
0.057
0.068
0.047
0.055
0.586
0.775
0,100
0.084
0.087
Total observations for each parameter, 240;
- UVB, 80; irradiance, 8
62
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TABLE PEL-1.
MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
PEA FOLIAGE WEIGHT, LAMP EXPOSURE 138 HRS
DURING 23 DAYS
UVB LAMP IRRADIANCE
FRESH WT
DRY WT
Weighted
mW.m
3.83
3.22
2.52
.89
.59
1.
1.
0.88
0.44
- UVB means
Non-weighted
-2
mW.m
416
348
273
204
170
94
47
Source df.
- UVB 2
Error a 2
Irradiance 6
Interaction 12
Error b 18
4-UVB
3
4
3
4
3
4
3
3
CA
g
.8
.1
.9
.2
.7
.5
.5
.9
-UVB
M
g
3.8
3.7
4.1
4.0
3.9
3.6
4.4
3.9
4
3
4
4
4
3
4
4
U
g
.9
.9
.6
.3
.1
.6
.6
.3
Mean
+UVB
CA
g
0.51
0.55
0.52
0.55
0.49
0.59
0.48
0.53
-UVB
M
i
0.
0.
0.
0.
0.
0.
0.
0.
52
50
56
54
53
48
62
54
U
g
0.68
0.54
0.63
0.56
0.56
0.50
0.66
0.59
squares
Fresh wt
2.38
0.95
0.50
1.13
1.19
Dry wt
0.
0.
0.
0.
0.
0608
0188
0135
0244
0261
Total observations for each paramter, 168;
- UVB 56; irradiance, 8
63
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TABLE PEL-2.
MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
PEA FOLIAGE WEIGHT, .LAMP EXPOSURE 168 HRS
DURING 28 DAYS
UVB LAMP IRRADIANCE
FRESH WT
.DRY WT
+UVB
-UVB
+UVB
-UVB
Weighted Non-weighted
mW.m
-2
.83
.22
.52
.89
1.59"
0.88
0.44
3.
3.
2.
1.
mW.m
416
348
273
204
170
94
47
-2
CA
g
5.8
6.3
7.3
7.4
6.8
6.8
6.9
M
g
6.4
6.7
6.6
7.0
6.5
6.5
6.0
U
g
8.1
7.0
7.3
7.3
7.5
6.5
7.5
CA
g
0.96
1.02
1.15
1.17
1,06
1.14
1.13
M
g
1.01
1.03
1.01
1.13
1.03
1.04
0.99
U
g
1.26
1.10
1.13
1.14
1.19
1.05
1.23
- UVB means
6.8. 6.5, 7.3
1.09;; 1.03 1.16
b c a
Mean squares
Source
df.
- UVB
Error a
Irradiance
Interaction
Error b
2
2
6
12
18
Fresh wt
9.38*
0.28
1.24
2.02
1.04
Dry wt
0.2196*
0.0034
0.0243
0.0440
0.0190
Total observations for each parameter, 168;
- UVB 56; irradiance, 8
- UVB mean separation (within parameter) by LSD, 5% level.
Means followed by the same letter are not significantly
different.
64
-------
TABLE PEL-3.
MEANS AND MEAN SQUARES FROM LAMP EXPERIMENT,
PEA PLANT HEIGHT, LAMP EXPOSURE 138 HRS
DURING 23 DAYS
UVB LAMP IRRADIANCE
PLANT HEIGHT
4-UVB
-UVB
Weighted
-2
mW.m
,83
,22
,52
,89
,59
0.88
0.44
Non-weighted
mW.m
416
348
273
204
170
94
47
-2
CA
cm
23.0
22.6
24.0
24.0
23.1
21.5
22.1
M
cm
23.4
21.2
23.3
22.8
20.5
21.2
24.3
U
cm
25.4
22.4
24.1
23.9
23.1
22.0
25.6
- UVB means
22.9 22.4 23.8
Source
df.
Mean squares
Plant height
- UVB
Error a
Irradiance
Interaction
Error b
2
2
6
12
18
Total observations for each parameter, 168;
- UVB 56; irradiance, 8
28.80
9.29
25.78
6.50
9.93
65
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