Oxidative Stress and Antioxidative Defence System in Plants in Response to UV‐B Stress

Abstract

Plants use antioxidant enzymes to remove reactive oxygen species (ROS) in cells directly or indirectly, thus ensuring normal metabolic reactions, which is a major mechanism to ameliorate the toxic effect of ROS generated by UV-B stress. The key factor for UV-B tolerance may be considered as UV-B-absorbing pigments, regulation of active oxygen species levels and activity of antioxidants, and the effective repair mechanism for PSII, one of the important components of photosynthetic electron transport chain. This chapter discusses the oxidative stress and antioxidative defence system in plants in response to UV-B stress. In response to the damaging effects of UV radiation, plants have developed defence mechanisms against UV-B, while allowing photosynthetically active radiation (PAR) to penetrate through the outer cell layers to support photosynthesis in the mesophyll and palisade tissues. Efficient antioxidant defence systems, including antioxidants and enzymes, have developed in plants to counteract the toxicity of ROS.