Possible effects of iron,magnesium and zinc on the metabolism of reactive oxygen species in plants

The reactive oxygen species(ROS) are common free radicals in higher plants.Excess ROS are produced in plants when subjected to various environmental stresses and result in damages to plants.The possible effects of some nutrient elements such as iron,magnesium and zinc on the metabolism of ROS in plants were reviewed.The role of iron in generating ROS is mainly through Haber-Weiss reaction.The high levels of ROS caused by Mg deficiency induce the higher activities of detoxification enzymes of ROS.The main mechanism underlying is that plant photooxidation is enhanced by Mg deficiency since photosynthetic carbon fixation is inhibited or slows down under Mg deficiency.Increasing evidences show that oxidative damages to cell resulting from the attack by ROS are the basis of disturbances in plant growth caused by zinc deficiency.Under zinc deficiency,membrane-bound NADPH oxidase producing ROS increases,while the activities of some detoxification enzymes of ROS reduce.The higher iron concentration is often observed in Zn deficient plants.Plant photooxidation is also enhanced by Zn deficiency.