Cadmium and lead-induced changes in lipid peroxidation, antioxidative enzymes and metal accumulation in<i>Brassica juncea</i>L. at three different growth stages

Abstract

Changes in malondialdehyde (MDA) concentration and antioxidant enzyme activities by Cd and Pb in mustard (Brassica juncea L.) plants at pre-flowering, flowering and post-flowering were investigated. On treatment with Cd, Pb, changes in MDA concentration and antioxidant enzyme activities, namely, superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) were observed. The lower concentrations of Cd and Pb did not have much impact on lipid peroxidation, but the higher concentrations (250 mg/kg soil Cd and 500 mg/kg soil Pb) proved to be very effective. Catalase activity was increased at lower concentrations and decreased at higher concentrations of Cd and Pb. SOD, APX and GR increases up to 200 mg/kg soil Cd and with Pb 300 mg/kg soil. Cd and Pb accumulate more at 200 mg/kg soil Cd and 300 mg/kg soil Pb in the shoots of B. juncea. This study demonstrated that B. juncea is tolerant to Cd and Pb and mobilizes antioxidant enzymes in order to mitigate heavy metal stress damages.