为了阐明锌胁迫对三峡库区消落带适生植物狗牙根(Cynodon dactylon(Linn.)Pers)的毒害机制,为锌污染水体、土壤植物修复提供理论依据.研究重金属锌对草本植物狗牙根新芽数、新根数、叶绿素、抗氧化酶系统的变化及重金属锌累积与分布的影响.结果表明:在0~80 mg/L Zn2+处理范围内,低浓度Zn2+对狗牙根新芽数、新根数及叶绿素含量表现出一定的促进性,新芽和新根数增加,叶片叶绿素含量提高;高浓度Zn2+导致狗牙根新芽和新根数、叶片叶绿素含量下降.当营养液中外源锌浓度< 40 mg/L时,狗牙根叶片中SOD、POD酶活性都增加,但当Zn2+浓度> 40 mg/L时,狗牙根叶片中SOD和POD酶活性降低,而CAT活性一直下降.狗牙根积累的锌主要分布于地下部分根,其次为茎.狗牙根能明显吸收江水中的Zn2+,故狗牙根可以用于修复被锌污染的水体、土壤,狗牙根具有潜在的应用价值.%In order to elucidate the toxic mechanisms of Cynodon dactylon under Zinc stress, this paper provides a theoretic foundation for phytoremediation of Zn2+-contaminated water, and screening experiment was conducted to investigate the effects of Zn2+on plant, the new sprout number, the new root number, the contents of chlorophyll, the activities of superoxide dismutase (SOD), peroxide enzyme (POD), catalase (CAT) in the leaves and Zn2+ accumulation and distribution in C. dactylon.The results indicated that the new root and bud number and the chlorophyll content of C.dactylon were increased under lower Zn2+ concentrations. However, lower new root, bud number and chlorophyll content were observed for the higher Zn2+concentrations.The activities of SOD, POD were increased under40 mg / l Zn2+, but the activities of SOD, POD were decreased above 40mg / l Zn2+. CAT has been on the decline. Zn2+was distributed firstly in the C. Dactylon of roots and the secondly in the stems. This investigation also showed that C. dactylon could decrease the content of Zn2+ in polluted water. The results suggest that C. dactylon be promising for the phytoremediation of Zn2+-contaminated soil and water.
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