Screening of cytotoxic and genotoxic potency of two pesticides (malathion and cypermethrin) on Allium cepa L.

Background Malathion (organophosphate) and cypermethrin (pyrethroid) are widely in use to facilitate protection of major food crops in agriculture, due to which it is important to understand their toxic potential. Allium cepa L. has been considered as a reliable genetic model to detect the toxicity of all sorts of pollutants. Objective The objective of the present work is to determine the cytotoxic and genotoxic effects of two widely used pesticides (malathion and cypermethrin) using A. cepa assay. Allium root growth inhibition test showed 0.5% concentration as the EC50 value in both the pesticides. In the toxicity experiment, 1/10 x EC50; 1/5 x EC50; EC50; 2 x EC50 and 3 x EC50 concentrations of both the pesticides along with a control were employed in Allium assay. Results Cytotoxic study showed mitotic index decreased with increasing the pesticides concentrations and exposure time. A series of mitotoxicity was observed under the influence of malathon and cypermethrin. Most types of chromosome aberrations observed in high percentage were stickiness, disturbance, c-metaphase, chromosome bridges in anaphase, lagging chromosome, and binucleate lesions. It was observed that malathion and cypermethrin are highly genotoxic to the onion, causing aberration at different phases of mitosis which can arrest cellular growth and may lead to senescence. Conclusion In conclusion, the present results showed that malathion and cypermethrin can get absorbed in the exposed plant parts or other non-target organisms in the vicinity, and may adversely affect their genomes, thus cause significant harm to crop plants and the environment as well.