Figure 3: Effect of different concentrations of lead (Pb) (0, 50 and 100 μM) and silicon (0 and 1 mM) on chlorophyll a (A), chlorophyll b (B), total chlorophyll (c), total carotenoid (d) and SPAD value (E) in cotton plants. Values show the means of three replicate ± SE. Means followed by same small letter are not significant different by the Tukey test at P ≤0.05.