Biochemical Responses of Capsicum Annum Under Cadmium Stress

Abstract

A pot culture study was carried out to assess the antioxidant activity, lipid peroxidation and DNA damage in Capsicum annum (L.) var. Vellayani athulya, under different cadmium concentrations applied as cadmium chloride salt (10mM, 20mM, 30mM, 40mM and 50mM). Activities of superoxide dismutase (SOD), peroxidase (POX), catalase (CAT) and reduced glutathione (GSH) were observed along with lipid peroxidation and DNA damage. Results showed significant changes in the activities of above antioxidants in test plants, compared to control. A significant increase in the activity of SOD, POX and decrease in the activities of CAT and GSH were observed up to 30mM concentrations. However, at 40mM concentration, the activity of antioxidants was observed to revert to the near normal, showing a sign of recovery which may be due to the inactivation of antioxidants in the presence of excess Cd. Further, in 50mM concentration, the activity of enzymes reversed to the initial condition, i.e either increased or decreased. Nevertheless, production of malondialdehyde, which is an indicator of lipid peroxidation, also showed the same pattern of change. The results of comet assay showed that the extent of DNA damage was greater in C. annum as the Cd concentration increased.