Figure 5: Effect of different concentrations of lead (Pb) (0, 50 and 100 μM) and silicon (0 and 1 mM) on superoxidase dismutase (SOD) of leaf (A) root (B), guaiacol peroxidase of leaf (C) root (D), catalase (CAT) of leaf (E), root (F) and ascorbate peroxidase (APX) of leaf (G) and root (H) in cotton plants. Values show the means of three replicate ± SE. Means followed by same small letters are not significant different at P ≤ 0.05 by using the Tukey test.