Several component reactions of photosynthesis, and net C0₂ assimilation rates have been shown to be detrimentally affected by UV-B radiation levels equal to or above those presently received at various locations on the earth's surface. Many of these studies, however, were completed under environmental conditions that deviated from ambient field conditions to such an extent that extrapolation of results for predictive purposes would probably overestimate the harmful effects of reduced atmospheric ozone levels and the concomitant increases in UV-B radiation. Nevertheless, the photosynthetic process has been shown to be sensitive to UV-B radiation and, therefore, warrants further study. The ability of plants to tolerate increased levels of UV-B radiation, relative to photosynthetic capacity, may be dictated by acclimation processes that would intensify UV-B attenuation prior to its absorbance by sensitive components or reactants of photosynthesis