Meeting Abstract
Plants have mechanisms to sense ultraviolet radiation as both a stressor and developmental signal and regulate their responses to changes in their light environment. In particular, plants exposed to UV-B (280 to 315 nm) display unique responses such as inhibited growth and pigment production. UV-B varies seasonally and is absorbed by ozone and therefore varies with altitude and proximity to urban centers, meaning that plants grown in these microclimates may display different UV-stress characteristics. The effect of seasonality and microclimate on plant responses to UV-B radiation was studied at three field sites of varying proximity to urban centers. At each field site, greenhouse-grown native Texas grasses (Bouteloua curtipendula and Chasmanthium latifolium) were placed for fourteen days under two filters, one which was UV transparent and one which blocked almost all energy at wavelengths shorter than 300 nm. The effects of high energy UV-B radiation on plant function were characterized with UV absorbance spectra taken from leaf pigment extracts, reflectance spectra obtained from whole leaves, and leaf flavonoid content. The location of the grasses had a small and directionally inconsistent effect on each of the characteristics of UV stress, whereas seasonality had a large and consistent impact on the grasses’ UV stress responses. As expected, the grasses began with a moderate UV-stress responses, which grew to their peak at the summer solstice before gradually returning to its initial level. Together, these results emphasize plants’ ability to sense and respond to minute changes in their light environment.
