外源亚精胺缓解荇菜(Nymphoides peltatum)Cr6+毒害的生理研究

研究了不同浓度的Cr^6 胁迫下，荇菜叶中叶绿素含量、可溶性蛋白含量、O2^-产生速率、保护酶——超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的动态变化及外施亚精胺后对上述各指标的影响．结果表明：(1)单一Cr^6 处理下，叶绿素和可溶性蛋白含量在Cr^6 浓度为1mg／L时达到最大值，而后迅速下降；外施亚精胺(Spd)可显著提高二者的含量，延缓它们的下降速度．(2)单一Cr^6 处理下，SOD、POD、CAT活性分别在2、4、2mg／L Cr^6 处理下达到最大值．而后下降；外施亚精胺可提高这三种保护酶的活性，使其上升或稳定时期变长，从而降低O2^-等活性氧的产生速率．由此可见外源亚精胺可缓解Cr^6 对荇菜的胁迫效应．

Toxic effects of Cr6+ on Nymphoides peltatum mitigated by exogenous spermidine

Changes of chlorophyll content, soluble protein content, O₂ generating rate and activity of protective enzymes (SOD,CAT,POD) in leaves of Nymphoides peltatum (Gmel) O.Kuntze under different concentration gradient of Cr⁶⁺ stress or exogenous spermidine treatment were studied. The results showed that:(1)under single 1mg/L Cr⁶⁺ stress, chlorophyll and soluble protein contents of the Nymphoides peltatum reached maxima, then decreased quickly; the contents of them were much higher in additionally spraying spermidine (Spd) than those in the only single Cr⁶⁺ treatment.(2)under single Cr⁶⁺ stress, the maxima of SOD,CAT and POD appeared at 2,4 and 2 mg/L Cr⁶⁺ respectively, and decreased afterward; the activities of these protective enzymes were markedly higher in spermidine treatment than those of control while the increasing and steady periods lasted longer, thereby it decreased the generation rate of active oxygen species (for example, O₂). So it was concluded that spermidine could alleviate the toxic effects caused by Cr⁶⁺ stress.