Chromium(VI) Toxicity in Legume Plants: Modulation Effects of Rhizobial Symbiosis

Figure 1

Toxic effects of Cr(IV) on plants. Like other heavy metals, Cr can directly inactivate many proteins binding to them or displacing metals from the active centers of proteins. As a transition metal, Cr can participate in many cellular redox reactions resulting in generation of reactive oxygen species (ROS) such as , H₂O₂, and HO^•. When the production of ROS exceeds the capacity of the antioxidant system, cells undergo oxidative stress. Both direct protein inactivation and oxidative stress lead to adverse morphological and physiological changes in plants.