Effects of Hg2+ on isozymes of peroxidase, catalase and superoxide dismutase in wheat seedlings

[Objective] This work was aimed to explore the mechanism of Hg2+ toxicity on plants.[Method]Activities of peroxidase,POD;catalase,CAT and superoxide dismutase,SOD were investigated in wheat(Triticum aestivum L.)seedlings under Hg2+ stress at different concentrations.[Result] There were no obvious effects on the growth of seedlings when the concentration of Hg2+ was lower than 0.100 mmol/L.However,toxic effects on the growth of seedling were observed when the concentration of Hg2+ was higher than 0.100 mmol/L.Different tissues showed different resistant ability in response to Hg2+ stress.The leaves and roots of wheat seedlings were more insensitive to Hg2+ toxicity.CAT was more sensitive to Hg2+ stress compared to POD and SOD.[Conclusion] The toxic effect was related to the concentration of Hg2+(0.100 mmol/L).Some studies revealed that Hg2+ could affect the expression of POD,CAT,and SOD isozymes in the leaves,roots of wheat seedlings and germinated seeds,which further affect the normal metabolism of membrane lipid and inhibit the growth of wheat seedlings at last.