Effect of Sulfate on Copper Toxicity to Rice Seedlings

Rice seedlings were cultivated in hydroponic culture solution with supplies of copper((Cu)0.16, 100 μmol·L-1, and 1 mmol·L-1)and sulfate((S)1 and 10 mmol·L-1)under controlled growth conditions. The copper concentrations of leaves and roots, the pigments, ascrobate acid(AsA)contents and enzymes(dehydroascorbate reductase(DHAR)and ascorbate peroxidase(APX))activities were investigated during 12 h treatment. The result indicated, the sulfate(10 mmol·L-1)which exerts higher concentration could suppress the plant root absorption and accumulation of Cu, but could promote the transportation and accumulation of Cu to shoots. This research still indicated, 0~3 hours when Cu is treated, the sulfate could facilitate the improvement of the content of AsA, and no significant difference was observed between two sulfate concentration treatments. Furthermore, sulfate could activate antioxidative enzymes and reduce toxic effect by Cu stress. In detail, the higher sulfate concentration could more rapidly induce to the increase of DHAR and APX activity than lower sulfate concentration. However, the sulfate or Cu of different concentrations impact on content of chlorophyll was not obvious. All experiment results suggested that sulfate could effectively reduce copper toxicity to seedlings.