Plant responses to heavy metals during cultivation in mining dump sites

Abstract Mining sites and vicinity areas show high level of heavy metal contamination. Plants growing in these areas show high rate of metal accumulation. Accumulation of heavy metals at high levels severely affects the physiological and biochemical processes in plants. Oxidative stress induced by heavy metal stress triggers enzymatic and nonenzymatic defensive mechanisms in plants. Antioxidants compounds viz. glutathione, proline, ascorbic acid, carotenoids, nonprotein compounds rich in thiol groups (–SH), and antioxidant enzymes such as superoxidase dismutase, catalase, glutathione peroxidase, and guaiacol peroxidase (GPX) assist the plant in tolerating oxidative stress. They also play a role in metal detoxification by scavenging reactive oxygen species (ROS). The study of plant responses to heavy metals can prove useful in suggesting tolerant species that can be used for rehabilitation of mining areas and dumping sites.