Cytotoxic and Genotoxic Effects of Clopyralid Herbicide on Allium Cepa Roots

Abstract Clopyralid is a one of the synthetic pyridine-carboxylate auxin herbicides and used to control perennial and annual broadleaf weeds in wheat, sugar beets and canola etc. In this study, dose dependent cytotoxicity and genotoxicity of clopyralid at different concentrations (25, 50, and 100 µg/mL) on the Allium cepa roots were evaluated at macroscopic (root growth) and microscopic levels (Mitotic index (MI), chromosome aberrations (CAs) in ana-telophase cells and DNA damage) using root growth inhibition, Allium ana-telophase and comet tests. The percentage root growth inhibition and concentration reducing root growth by 50% (EC50) of clopyralid in relation to the negative control were determined by using various concentrations of clopyralid (6.25–1000 µg/L). The 96 h EC50 of clopyralid was recorded as 50 µg/L. The gradual decrease in root growth and the MI reveals the cytotoxic effects of clopyralid. All the tested concentrations of clopyralid induced total CAs (polyploidy, stickiness, anaphase bridges, chromosome laggards, and disturbed ana-telophase) and DNA damage dose and time dependently. This study confirmed cytotoxic and genotoxic effects of clopyralid on non-target organism.