Meeting Abstract
The differences in plant responses due to short wavelength ultraviolet-B radiation (UV-B) (290 – 300 nm) was evaluated in both laboratory and natural light environments (field studies). UV-B radiation has been observed to cause plants damage, in addition to leading to acclimation. We characterized response of Texas native grasses to full spectrum UV radiation and those receiving radiation that blocks the short wavelength UV-B. Big Bluestem (Andropogon gerardi), Little Bluestem (Schizachyrium scoparium), and Sideoats Grama (Bouteloua curtipendula) were used for the experiment. To test the effects of UV-B radiation, we used two types of treatments to generate differences in UV-B radiation, a UV supplementation protocol in a greenhouse and a pair of UV exclusion enclosures covering plants placed at sites across South Texas during summer (highest UV-B) and fall. For greenhouse supplementation treatments, plants were maintained in a greenhouse supplying no UV-B radiation and exposed for five days to either UV-B radiation excluding wavelengths shorter than 300 nm or UV-B radiation including 15% at wavelengths below 300 nm. From both field sites and greenhouse studies we found that effects of short wavelength UV-B tend to be species specific. For four different field sites, the exclusion of short wavelength UV-B caused a decrease in absorption at 330 nm in Big Bluestem ranging from 3% to 40%. Two greenhouse studies exhibited opposite results with the addition of short wavelength UV-B causing increases in 330 nm absorption ranging from 50% to 58%. Considering that both sets of plants were grown in the same pots and soil, and were kept watered, it appears that other unidentified abiotic factors were the cause of the marked differences observed.
