Cu^(2+)胁迫下三峡库区消落带的狗牙根生长状况及其铜富积效应

Growth Status and Copper Enrichment Effect of Cynodon dactylonin Hydrofluctuation Belt of Three Gorges Reservoir Region Under Cu^(2+) Stress

为探明狗牙根遭受铜胁迫的毒害机制,采用水培的方法,模拟三峡库区长江水体Cu2+污染环境,研究不同浓度Cu2+胁迫对三峡库区库消落带生植物狗牙根(Cynodon dactylon)新芽和新根数、叶绿素含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的影响和Cu2+积累效应。结果表明,在0～40mg/L Cu2+对狗牙根植株生长没有明显伤害,甚至表现出一定的促进性,新芽和新根数增加,叶绿素含量提高;狗牙根叶片中SOD、POD、CAT活性均增加;当Cu2+浓度≥40mg/L时,狗牙根新芽和新根数、叶片叶绿素含量下降,叶片中SOD和CAT的活性被抑制,而POD活性略增加。同时,狗牙根对Cu2+的积累主要分布于根,其次为茎。

In order to identify the toxic mechanism of C. dactylon under copper （Cu2＋） stress, the effects of Cue＋ stress on the new root and bud number, chlorophyll content, activities of superoxide dismutase （SOD）, peroxide enzyme （POD） ,catalase （CAT） in the leaves and Cue＋ uptake in C. dactylon were studied by water culture method. The results indicated that Cu2＋ （0~40 rag/L） had no significant harm to the plant growth of C. dactylon. Or even promote C. dactylon growth. The new root and bud number, and chlorophyll content of C. dactylon increased under lower Cu2＋ concentrations（〈40 mg/L）. However, lower new root and bud number, and chlorophyll content were observed under higher Cu2＋ concentrations（≥40 mg/L）. The activities of SOD, POD and CAT were increased with increasing Cu2＋ concentration when Cu2＋ concentration was lower than 40 mg/L. However, when the content of Cu2＋ was larger than 40 mg/L, the activities of SOD and CAT decreased gradually. Cu2＋ was mainly distributed in the roots of C. dactylon and the second in the stems.