精胺对荇菜抗氧化酶系汞毒害的缓解作用

Mitigation effects of spermine on Hg injury of Nymphoides peltatum’s antioxidant enzyme system

研究了外施不同浓度的精胺（Spm）对15μmol·L^-1汞胁迫下，荇菜（Nymphoides pehatum）叶中SOD、CAT、APX、POD保护酶的活性、O2^-产生速率、MDA、叶绿素、可溶性蛋白、游离态多胺含量的影响。结果表明：外施0．05～0．5mmol·L^-1的Spn，显著提高了汞胁迫下荇菜叶内的亚精胺、精胺水平以及叶绿素和可溶性蛋白的含量；并能提高SOD、CAT和APX的活性，降低O2^-的产生速率，减缓MDA的积累；0．05～0．5mmol·L^-1的外源Spm可增强植物抗氧化胁迫的能力，缓解汞对荇菜的毒害作用，其中0．05～0．1mmol·L^-1的外源Spm效果最佳，但当Spm浓度达到5mmol·L^-1时，却加剧了汞的毒害作用。

This paper studied the effects of different concentration exogenous spermine （Spm） on the activities of antioxidant enzymes （SOD, CAT, POD, APX）, generation rate of O2^-, and contents of MDA, free polyamines （PAs） , chlorophyll and soluble protein in Nymphoides peltatum leaves under 15 μmol· L^-1 Hg stress. The results showed that under the Hg stress, 0. 05-0. 5 mmol·L^-1 of exogenous Spin could significantly increase the contents of leaf spermidine （Spd） , Spin, chlorophyll, and soluble protein, promote the activities of SOD, CAT, and APX, and decrease the generation rate of Of and the accumulation of MDA. It was suggested that 0. 05-0. 5 mmol·L^-1 of exogenous Spm could enhance the resistance of N. peltatum to oxidant stress, and mitigate the toxic effects of Hg. The optimum dose of exogenous Spin was 0.05-0. 1 mmol·L^- 1, while 5 mmol· L^-1 of Spin could aggravate the toxic effects of Hg.