LAUSR

The present study emphasized to explore the toxicity effect of malathion on plants using Allium test. The experiments explored the mitotic inhibition, growth and activity of antioxidant enzymes in roots of Allium cepa at different concentrations (50, 125, 250 and 375 ppm) of malathion under different exposure periods (3, 9 and 18 h). The results revealed that all concentrations of malathion were capable to decline the root growth. Malathion-induced mitotic alterations varying from reduction in mitotic index (MI), relative division rate (RDR) and phase distribution along with large number of chromosomal aberrations. These changes were of varying degree depending on the concentration and treatment period. The roots treated with malathion (375 ppm) showed significant (p ≤ 0.05) higher levels of superoxide dismutase and catalase than the control, while the activity of peroxidase was significantly (p ≤ 0.05) low. At 375 ppm malathion, malondialdehyde content was significantly high (p ≤ 0.05) that was increased with the treatment period. Findings concluded that variations in mitotic index, chromosomal aberrations, alterations in malondialdehyde content and activities of antioxidant enzyme could serve as the useful indicators for monitoring the effects of malathion exposures in the real scenario. Superoxide dismutase and catalase enzyme play vital roles in the antioxidant defence mechanisms under malathion toxicity. According to the data on the malondialdehyde content show malathion to be capable of producing superoxide radicals indirectly, and to result in membrane damage and oxidative stress.