Preventive Mechanisms to UV-B Radiation Damages in Crops

Since the discovery of the Antarctic ‘ozone hole’ and general depletion of the stratospheric ozone layer in the mid-1980 s,significant interest in documenting the effects of UV-B radiation (280 nm~315 nm) on organisms and ecosystems has been one of the most important concern of global change.A substantial number of studies have been intensively conducted over the last several decades to assess the potential impacts of long-term increases in ultraviolet-B radiation on crop plants,and have shown a diverse range of responses.Direct effects of natural or enhanced levels of UV-B radiation on plant yield have been detected to be modest,with growth reductions generally not exceeding 20% under field conditions.This limited impact reflects the activity of protective mechanisms in crop plants.This article summarizes changes at the physiological,morphological,biochemical and molecular levels,and proposes several future avenues with an aim to better understand the mechanisms whereby solar UV-B radiation boosts the expression of natural plant defenses.It could provide important elements for biotechnological,traditional crop breeding and viable cropping strategies programs.