THE EFFECTS OF CADMIUM ON THE ANTIOXIDATIVE RESPONSES OF LEAVES OF Brassica oleracea L. var. acephala

Abstract

In this study, Brassica oleracea L. var. acephala seedlings were treated with different cadmium (Cd) concentrations (100, 200 ve 400 mu g g(-1)) for 15 days. At the end of the treatment, the effects of Cd on the pigment content, lipid peroxidation, enzymatic and non-enzymatic antioxidants were investigated in leaves. In addition, Cd content in leaves and roots were determined by atomic absorption spectrophotometer. The pigment and carotenoid contents did not vary at all Cd treatments. The Cd content in roots were higher compared with leaves. Cd treatment caused an increase in the lipid percoddation product (malondialdehyde) in leaves. Malondialdehyde content increased significantly at 400 mu g g(-1). Cd toxicity caused changes in antioxidant enzymes activities. All these treatments depend on concentration caused decrease in superoxide dismutase (SOD) activity, increase in guaiacol peroxidase (GPOX) activity. However, there was no significant change in catalase (CAT) activity. Ascorbate peroxidase (APX) activity increased significantly at 200 mu g g(-1). The analysis of the antioxidative enzymes activity indicated that GPOX was the most active enzyme in leaves of B. oleracea var. acephala. While proline content was decreasing, non-protein thiol groups and total ascorbate contents increased at all Cd treatment.