scholarly journals Influence of Ambient UV-A and UV-B on Growth, Chlorosis, and Flavonoid Content of Cucumber

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 898C-898
Author(s):  
Donald T. Krizek ◽  
Roman M. Mirecki ◽  
Steven J. Britz
Keyword(s):  
Uv Radiation ◽  
Root Biomass ◽  
Floral Development ◽  
Differential Sensitivity ◽  
Flavonoid Content ◽  
Total Leaf Area ◽  
Solar Uv ◽  
Extreme Sensitivity ◽  
Stem Leaf ◽  
Uv Exclusion

The influence of ambient UV radiation on growth, chlorosis, and flavonoid content was examined in four cultivars of cucumber (`Ashley', `Poinsett', `Marketmore', and `Salad Bush'). Plants were grown from seed in UV exclusion chambers consisting of UV transmitting plexiglass (10% T, 285 nm), lined with 3- or 5-mil Llumar (10% T, 399 or 404 nm) to exclude UV-A and UV-B, 5-mil polyester (10%T, 319 nm) to exclude UVB, or cellulose acetate (10% T, 291 nm) to transmit UV-A and UV-B. Plants were grown in 15 cm plastic pots containing vermiculite and were fertilized daily with nutrient solution. Despite their differential sensitivity to supplemental UV-B radiation, all four cultivars responded similarly to the exclusion treatments. After 19 to 21 days, plants grown under ambient UV-A and UV-B generally had less stem, leaf, and root biomass and less total height and total leaf area than those grown under conditions in which UV-A and UV-B or only UV-B was excluded. Flavonoid content, leaf number, and floral development were unaffected by UV. These findings demonstrate the extreme sensitivity of cucumber to current levels of solar UV radiation.

Effects of solar UV radiation on birch and pine seedlings in the sub-Arctic

Polar Record ◽  
2002 ◽  
Vol 38 (206) ◽  
pp. 233-240 ◽  
Author(s):  
M. Turunen ◽  
M.-L. Sutinen ◽  
K. Derome ◽  
Y. Norokorpi ◽  
K. Lakkala
Keyword(s):  
Uv Radiation ◽  
Dry Weight ◽  
Growing Season ◽  
Control Treatment ◽  
Daily Maximum ◽  
Solar Uv Radiation ◽  
Growing Seasons ◽  
Acrylic Plate ◽  
Solar Uv ◽  
Uv Exclusion

AbstractThe responses of Betula pubescens Ehr. (European white birch), B. pendula Roth (silver birch) and two provenances of Pinus sylvestris L. (Scots pine) to solar ultraviolet (UV < 400 nm) radiation were investigated in a UV-exclusion field experiment during the 1997–99 growing seasons in Finnish Lapland (68°N). The seedlings were grown from seed under UV-B exclusion (a clear polyester filter) and UV-B/UV-A exclusion (a clear acrylic plate) as compared to control treatment (a polyethene filter) and ambient plants (no plastic filter). The mean daily maximum solar biologically effective UV-B irradiance (UV-BE) was 88 mW m-2, 68 mW m-2, and 91 mW m-2 for 1997, 1998, and 1999. A number of growth and biomass variables, PSII (Photosystem II) efficiency, and total concentration of nitrogen were recorded during and/or at the end of the experiment. Exposure (191 d) to solar UV radiation over three growing seasons did not cause many statistically significant UV effects in the growth or biomass of the seedlings. The only significant impacts of UV exclusion were found in P. sylvestris provenance Enontekiö. During the first growing season, the UVB/ UV-A exclusion treatment significantly accelerated the height increment (18–20%) off. sylvestris, and in the same seedlings, the UV-B exclusion treatment resulted in significantly increased dry weight of one-year-old needles (45–57%) after the second growing season. These UV impacts could not be seen at the end of the experiment or in any other species. The low concentration of N in current foliage was related to increased dry weight, but not to solar UV radiation (control vs UV exclusion). The present study indicated that solar UV radiation had limited, but sometimes transient, impacts on the growth of tree seedlings in the sub-Arctic. Longer-term field studies are needed, however, in order to detect the cumulative characteristics of the UV responses.

scholarly journals The Early Days of Personal Solar Ultraviolet Dosimetry

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 125 ◽  
Author(s):  
Brian Diffey
Keyword(s):  
Uv Radiation ◽  
Human Exposure ◽  
Ground Level ◽  
Uv Exposure ◽  
Population Exposure ◽  
Atmospheric Ozone ◽  
Quantitative Understanding ◽  
Solar Uv ◽  
The Impact ◽  
Solar Ultraviolet

In the early 1970s, environmental conservationists were becoming concerned that a reduction in the thickness of the atmospheric ozone layer would lead to increased levels of ultraviolet (UV) radiation at ground level, resulting in higher population exposure to UV and subsequent harm, especially a rise in skin cancer. At the time, no measurements had been reported on the normal levels of solar UV radiation which populations received in their usual environment, so this lack of data, coupled with increasing concerns about the impact to human health, led to the development of simple devices that monitored personal UV exposure. The first and most widely used UV dosimeter was the polymer film, polysulphone, and this review describes its properties and some of the pioneering studies using the dosimeter that led to a quantitative understanding of human exposure to sunlight in a variety of behavioral, occupational, and geographical settings.

scholarly journals Biologically effective doses of ambient solar-UV radiation in Indonesia and Japan

2000 ◽  
pp. 123 ◽  
Author(s):  
Nobuo Munakata ◽  
Santoso Cornain ◽  
Ketut Mulyadi ◽  
Masamitsu Ichihashi ◽  
Joedo Prihartono ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Solar Uv Radiation ◽  
Solar Uv ◽  
Effective Doses

Solar UV radiation variations and their stratospheric and climatic effects

1985 ◽  
Vol 5 (6) ◽  
pp. 145-148 ◽  
Author(s):  
Richard F. Donnelly ◽  
Donald F. Heath
Keyword(s):  
Uv Radiation ◽  
Climatic Effects ◽  
Solar Uv Radiation ◽  
Solar Uv

scholarly journals Interaction between variable solar UV radiation and tropospheric circulations as a possible cause of five year oscillation in Earth rotation

2000 ◽  
pp. 51-56
Author(s):  
P. Jovanovic ◽  
D. Djurovic
Keyword(s):  
Uv Radiation ◽  
Earth Rotation ◽  
Solar Uv Radiation ◽  
Solar Uv ◽  
Possible Cause

It is shown that Five Year Oscillation in Earth rotation is possibly caused by variable solar UV radiation and a corresponding perturbation mechanism is suggested.

scholarly journals Effects of Solar UV Radiation on Morphology and Photosynthesis of Filamentous Cyanobacterium Arthrospira platensis

2005 ◽  
Vol 71 (9) ◽  
pp. 5004-5013 ◽  
Author(s):  
Hongyan Wu ◽  
Kunshan Gao ◽  
Virginia E. Villafañe ◽  
Teruo Watanabe ◽  
E. Walter Helbling
Keyword(s):  
Solar Radiation ◽  
Cell Density ◽  
Uv Radiation ◽  
Time Scales ◽  
Morphological Development ◽  
Filamentous Cyanobacterium ◽  
Solar Uv Radiation ◽  
Solar Uv ◽  
Adaptive Time ◽  
The Impact

ABSTRACT To study the impact of solar UV radiation (UVR) (280 to 400 nm) on the filamentous cyanobacterium Arthrospira (Spirulina) platensis, we examined the morphological changes and photosynthetic performance using an indoor-grown strain (which had not been exposed to sunlight for decades) and an outdoor-grown strain (which had been grown under sunlight for decades) while they were cultured with three solar radiation treatments: PAB (photosynthetically active radiation [PAR] plus UVR; 280 to 700 nm), PA (PAR plus UV-A; 320 to 700 nm), and P (PAR only; 400 to 700 nm). Solar UVR broke the spiral filaments of A. platensis exposed to full solar radiation in short-term low-cell-density cultures. This breakage was observed after 2 h for the indoor strain but after 4 to 6 h for the outdoor strain. Filament breakage also occurred in the cultures exposed to PAR alone; however, the extent of breakage was less than that observed for filaments exposed to full solar radiation. The spiral filaments broke and compressed when high-cell-density cultures were exposed to full solar radiation during long-term experiments. When UV-B was screened off, the filaments initially broke, but they elongated and became loosely arranged later (i.e., there were fewer spirals per unit of filament length). When UVR was filtered out, the spiral structure hardly broke or became looser. Photosynthetic O2 evolution in the presence of UVR was significantly suppressed in the indoor strain compared to the outdoor strain. UVR-induced inhibition increased with exposure time, and it was significantly lower in the outdoor strain. The concentration of UV-absorbing compounds was low in both strains, and there was no significant change in the amount regardless of the radiation treatment, suggesting that these compounds were not effectively used as protection against solar UVR. Self-shading, on the other hand, produced by compression of the spirals over adaptive time scales, seems to play an important role in protecting this species against deleterious UVR. Our findings suggest that the increase in UV-B irradiance due to ozone depletion not only might affect photosynthesis but also might alter the morphological development of filamentous cyanobacteria during acclimation or over adaptive time scales.

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