Reactive Oxygen Species (ROS) Generation and Detoxifying in Plants

Environmental stresses present major challenges in our quest to achieve sustainable food production. The reactions of plants to environmental stresses are complex and involve many kinds of physiological and biochemical responses. Stress causes multifarious adverse effects in plants. Production of a family of reactive oxygen species (ROS) is a common phenomenon. When plants are subjected to environmental stress, the balance between the production of ROS and the quenching activity of antioxidants is upset, often resulting in an oxidative damage. Plants with high levels of antioxidant enzyme activity are reported to have greater resistance to this oxidative damage. The activities of component enzymes or the antioxidant levels are usually only double in response to many stress situations. This rather moderate response might be understood if we consider that the system is geared to self-destruction when it comes under threat. Understanding the mechanisms by which plants perceive environmental signals and transmit the signals to cellular machinery to activate adaptive responses is of fundamental importance to biology. The present review is focusing on ROS generation and plant defenses to them.