模拟酸雨引起水体pH下降导致Zn对金鱼藻的毒害

Effects of Zn toxicity on Ceratophyllum demersum L under low pH value

用模拟酸雨沉降方式研究了水体酸度增加条件下 ,5 0mg·L-1Zn2 +对金鱼藻的毒害 ,以探讨酸雨沉降下重金属对植物伤害的作用机理 .结果表明 ,随着pH降低 ,金鱼藻的细胞膜透性增加 ,叶绿素含量和叶绿素a b值逐渐降低 ,游离脯氨酸含量明显增加 ;O 2 与脂质过氧化产物丙二醛 (MDA)含量 ,均随酸度增加而升高 ,且两者极显著性相关 .在低pH下 5 0mg·L-1Zn对金鱼藻的胁迫过程中 ,过氧化物酶 (POD)活性发生大幅度应激性升高 ;CAT活性则在pH3 5以下明显下降 .金鱼藻对Zn的富集量在pH5 5时最高 ,随着酸度加大 ,富集量呈明显下降趋势 .提示 ,酸度增加使Zn离子化程度升高 。

Effects of 50?mg·L -1 Zn 2+ with increased on acidity \%Ceratophyllum demersum\% L were studied. The results showed that the contents of free proline, O  2, MDA and permeability of cell membrane increased while chlorophyll contents decreased with decrease of pH value . POD was induced significantly by low pH value and CAT activity decreased evidently when pH value was less than 3.5. Accumulation of Zn by \%Ceratophyllum demersum\% L was the highest at pH5.5 and decreased with increase of acidity,indicating that the direct reason of increase Zn toxicity on \%Ceratophyllum demersum\% L was the Zn ionization's enhancement induced by acidity increase.