Effect of mancozeb and chlorpyrifos on the activity of antioxidative enzymes of Allium: a, b Catalase (CAT); c, d Peroxidase (POD); e, f Superoxide dismutase (SOD). Data represent mean ± S.E. of 3 replicates and data with different superscripts (a, b, c, d, e, f, g and h) are significantly different at P < 0.05, as determined by ANOVA followed by Duncan’s multiple range test