Hg2+胁迫对小麦幼苗POD、CAT和SOD同工酶的影响

[目的]为研究Hg2+对植物的毒害机理提供理论依据。[方法]以小麦为材料,研究了不同浓度Hg2+胁迫对小麦幼苗中的过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)同工酶活性变化的影响。[结果]在Hg2+浓度低于0.100 mmol/L时,对小麦幼苗生长的影响不明显;在Hg2+浓度高于0.100 mmol/L时,将会显著阻碍小麦的正常生长发育。小麦幼苗的不同组织对Hg2+胁迫的抵抗强度有所不同,表现为其叶片和根的抗胁迫性比萌发的种胚要强。在小麦幼苗受Hg2+胁迫时,POD、CAT和SOD 3种抗氧化酶同工酶中,CAT同工酶最为敏感。[结论]0.100 mmol/LHg2+浓度是小麦幼苗能否正常生长的阈值。

Effect of Hg2+ on Isozymes of Peroxidase,Catalase and Superoxide Diamutase 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.