Cadmium-induced antioxidant status and sister-chromatid exchanges in Vicia faba L.

Authors: SERPİL ÜNYAYAR, AYŞİN GÜZEL DEĞER, AYLA ÇELİK, FAZİLET ÖZLEM ÇEKİÇ, SERTAN ÇEVİK

Abstract: The effects of cadmium (Cd) on antioxidant responses and sister chromatid exchanges (SCE) were studied in Vicia faba L. The activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR), and the levels of ascorbate (ASC), glutathione (GSH), hydrogen peroxide, and malondialdehyde (MDA, indicator of lipid peroxidation) were measured. Genotoxicity was evaluated by measuring the changes in the mitotic index (MI) and sister chromatid exchanges (SCE). Increased activities of SOD and CAT were observed in plants treated with 50 and 100 µM Cd. It was found that APX activity increased remarkably with 50 µM Cd, but no significant changes were found in GR activity in any of the treatment groups. These changes in antioxidant enzyme activities were negatively correlated with lipid peroxidation. However, a positive correlation between the increase of H2O2 levels and Cd concentration occurred with all levels of Cd. A significant increase in the malondialdehyde (MDA) level was only observed at the highest (200 µM) Cd concentration. This finding suggests that membrane damage did not occur in moderate Cd frequency. SCE increased significantly in high Cd concentration (200 µM), while MI decreased. The results suggest that exposure of high Cd concentrations is cytotoxic as well as genotoxic for Vicia faba L. and also suggest that the 2 phenomena are related.

Keywords: Cadmium, antioxidant system, sister-chromatid exchange, Vicia faba, genotoxicity

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