Lead induced genotoxicity and cytotoxicity in root cells of Allium cepa and Vicia faba

摘要

The cytotoxic and genotoxic effects of lead (Pb) were studied in A. cepa L. and V. faba L. The plants were exposed to lead nitrate [Pb (NO3)2] solutions at three concentrations (50, 100 and 200 μM), and root growth, root viability and antioxidant enzyme activity was assessed. In addition genotoxicity was evaluated by changes in the mitotic index (MI) chromosomal aberrations (CAs), and DNA strand breaks. The exposure to Pb caused serious damage in the roots, which was accompanied by a decrease in divisional frequency of cell, increase in chromosomal aberrations, DNA fragmentation and micronucleus frequency in both the plants. The enzymes guaiacol peroxidase (GPX) and catalase (CAT) activities increased in both the plants. Increased level of malonaldehyde (MDA) an indicator of lipid peroxidation was noted. A positive correlation of the activity of GPX and CAT with malonaldehyde (MDA) content was recorded at all concentrations of Pb. This finding suggest that exposure of high Pb concentration is cytotoxic as well as genotoxic for A. cepa L. and V. faba L., and are correlated to the oxidative stress.