Heavy Metal induced Genotoxicity Detection by RAPD in Alligator Weed

Abstract

Indiscriminate use of heavy metals for rapid urbanization and industrial exploration is a pressing threat to ecosystem and human health. Among this Cd and Cr contamination are most dangerous as these metals directly enter into the food chain due to their higher solubility and mobility. Identification of a metal tolerant native plant species would be helpful to decontaminate Cd and Cr polluted land. Alligator weed [Alternanthera philoxeroides ( Mart ) . Griseb ], is found to be the most widely distributed perennial stoloniferous herb in Cd, Cr contaminated areas in and around Kolkata. To establish metal accumulation capacity of this species, the shoot and root metal content of the plant samples collected from different Cd, Cr contaminated areas were estimated. Plants were also grown under laboratory condition with external application of various concentrations of Cd and Cr individually and synergistically ( 0.5, 0.8, 1.0, 1.2, 1.5, 1.8 mM) to assess maximum metal tolerance potential. Laboratory grown plants treated with Cd and Cr, showed higher amount of metal accumulation in comparison to in situ plants. Hyperacuumulation property of this plant was recorded in 1mM metal concentration. The genotoxicity of these metals on alligator weed was established by RAPD method. Out of ten primers, four primers showed polymorphic bands due to DNA damage or modified bases in primer binding sites. Distinct variation in DNA banding profile between control and treated plants revealed the deleterious effect of Cd, Cr on this plant which was also supported by decreasing GTS% with increasing metal concentration. Keywords: genotoxicity, cadmium, chromium, GTS, RAPD