Effect of Sulfur on Plant Growth and Some Physiological Characteristics of Wheat Seedlings Under Cadmium Stress

To better understand the role of endogenous sulfate in plant response to cadmium stress,changes in plant growth,chlorophyll content and enzymatic antioxidant were investigated in wheat(Triticum aestivum L.) seedlings grown hydroponically with Cd,with or without application of sulfate.Results indicated that higher concentration of Cd caused decreases of plant growth,chlorophyll content and activity of nitrate reductase in wheat seedlings.As compared to the control,cadmium significantly increased the content of H2O2 and malondialdehyde(MDA),decreased the activities of catalase(CAT) and peroxidase(POD).In presence of low-level cadmium(50 μmol·L-1),addition of 0.5 mmol·L-1 exogenous sulfates to the medium significantly increased the plant growth,the content of chlorophyll,and the activity of nitrate reductase,CAT and POD,but clearly decreased the content of H2O2 and MDA in wheat seedlings as compared to that of Cd treatment alone.The alleviation effects of sulfate on high-level cadmium were not significant.