Effects of cadmium on lipid peroxidation and activities of antioxidative enzymes in rape (Brassica napus L.) leaves

Activities of antioxidative enzymes such as catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD), malonyldialdehyde (MDA) content and lipoxygenase (LOX) activity in Cd-stressed leaves of rape (Brassica napus L. cv. Drakkar) seedlings were investigated. Plants were grown in hydroponic culture for 14 days and 0, 5, 10, 25 and 50 μM Cd was applied. Cd application increased the content of malonnyldialdehyde, suggesting that lipoxygenase could be responsible for initiation of lipid peroxidation. APX and CAT activities increased at 5 μM Cd but decreased thereafter at higher Cd concentrations. The electrophoretic profil of SOD enzyme revealed only one SOD isoenzyme in leaves of control plants and intensity of its band decreased with increased Cd doses. However, two SOD isoenzyme were identified at 10 μM of CdCl 2 .