AsA-GSH循环对水稻突变体耐汞性的作用

Effect of AsA-GSH Cycle on Hg^(2+)_-Tolerance in Rice Mutant

以水稻中花11及其汞耐性突变体的溶液培养,研究了在0.4mmolL-1Hg2+胁迫下汞耐性突变体的活性氧代谢及抗坏血酸-谷胱甘肽(AsA-GSH)循环的变化。结果表明,Hg2+胁迫下,突变体叶片中的H2O2含量、O-2产生速率和MDA含量、GSSG含量、DHA含量显著低于野生型;突变体叶片中GSH/GSSG和AsA/DHA的比值均高于野生型,同时突变体根和茎中的Hg2+含量明显高于野生型。说明汞耐性突变体体内AsA-GSH循环在Hg2+胁迫下仍能保持较高的运转效率和清除活性氧的能力,在其耐汞性中起重要作用。

Mercury （Hg） toxicity is an in rice growth problem throughout the world. In the present study, Zhonghua 11 and a Hg^2＋ -tolerant rice mutant （MT） were used in a solution culture to investigate the effect of 0.4 mmol L^-1 Hg^2＋ treatment on reactive oxygen species （ROS） metabolism and dynamic change of ascorbate-glutathione （AsA-GSH） cycle. The results indicated that the H2O2 content, O2^- evolution rate, MDA content, GSSG and DHAcontents of the leaves were higher in the wild type than in the mutant; both the ratio of GSH to GSSG and the ratio of AsA to DHA were higher in the mutant than in the wild type, while the accumulation of Hg^2＋ in roots and stems of the mutant was more than that of the wild type. The results reveal that AsA-GSH cycle was less inhibited in the mutant than in the wild type, thus the mutant was able to scavenge ROS more. An effective AsA-GSH cycle is important for the mercury resistance of mutant.