Activities of Antioxidative Enzymes, Sulphur Assimilation, Photosynthetic Activity and Growth of Wheat (Triticum aestivum) Cultivars Differing in Yield Potential Under Cadmium Stress

The increasing concentration of cadmium (Cd) in agricultural soil has resulted in crop productivity loss. The activation of the antioxidative enzyme system and its synergy with sulphur assimilation may be required as one of the mechanisms for the alleviation of the effects of Cd. In the present study the activities of antioxidative enzymes and sulphur assimilation were studied in Cd‐treated wheat (Triticum aestivum) cultivars to assess their involvement in determining yield potential. The cultivar WH542 (low yielding type) accumulated Cd to a greater amount in both root and leaf, and also exhibited higher contents of H₂O₂ and thiobarbituric acid reactive substance and the activity of superoxide dismutase (EC 1.15.1.1) than cultivar PBW343 (high yielding type). The activities of other antioxidative enzymes, catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11), glutathione reductase (EC 1.6.4.2) and glutathione peroxidase (EC 1.11.1.9), activity of ATP‐sulfurylase (EC 2.7.7.4), sulphur content, photosynthetic, growth and yield characteristics were higher in PBW343 than in WH542 in Cd treatment compared to the control. The results suggest that the efficient functioning of enzymes of the antioxidative system and sulphur assimilation helped in alleviating the effects of Cd in PBW343, protected photosynthetic ability and maintained high yielding potential of the cultivar.