A Comparative Analysis Of Cadmium And Chromiumr Toxicity And Detection Of Their Genotoxic Effect On Plants By Rapd (Review Article)

Abstract

Heavy metal pollution is an alarming environmental issue in today’s world. Among these cadmium and chromium are most important as huge amount of these metals are released in the atmosphere by anthopogenic activity. Due to rapid urbanization and indiscriminate use of cadmium and chromium in various factories these metals are getting access in food chain. Due to high solubility divalent Cd and hexavalent Cr (VI) get accumulated in soil and taken up by plants resulting acute phytotoxicity. Being biologically non essential both these metals with teratogenic effect are injurious to animal leading to cancers also. Various plants with greater capacity of metal accumulation have been identified and categorised as hyperaccumulator. These plants are potential candidate for ecofriendly phytoremediation process or decontamination of heavy metal polluted soil. Various biochemical defence mechanism of these plants are of great interest in new plant research areas. Overexpression of enzymatic (superoxide dismutase, glutathione reductase, ascorbate peroxidase) and non enzymatic (non protein thiole content, proline, tocopherol) antioxidants in these Cd, Cr resistant plants has been well reported. The genotoxic effect of Cd, Cr on plants has been evaluated and established very efficiently by RAPD method. Cd and Cr alter the primer binding sites on DNA and also induce point mutation which is evidenced by the DNA banding profile polymorphism between control and treated plants. Appearance of new bands and disappearance of control bands have been reported by various workers to confirm the genotoxic effect of these metals by RAPD method.