Reactive Oxygen Species and Nitric Oxide in Plants Under Cadmium Stress: From Toxicity to Signaling

Abstract

The toxicity of heavy metals as a result of increasing environmental pollution in living organisms has become a major focus of research in recent decades. Among the heavy metals cadmium is one of the most dangerous heavy metals because of its high mobility in plants. It causes severe disturbances in plant metabolism that affect photosynthesis and water/nutrient balance, and it also causes oxidative damage. Although there is an enormous literature on the tolerance and accumulation of cadmium in plants, very little research has been performed on the molecular mechanisms and signaling events underlying plant responses to Cd toxicity. The dual role as both oxidative damage inducers and signaling molecules of ROS and NO in heavy metal toxicity has been demonstrated by many workers. In this chapter, we review the contribution of different ROS and NO sources in cells and their role in regulating cellular responses to Cd.