中文摘要：

研究了不同浓度的Cr^6＋（0、1、10、30、50 mg.L^-1）对菹草叶片叶绿素、叶绿素荧光参数、抗氧化系统、可溶性蛋白含量、膜脂过氧化产物、可溶性糖含量、超氧阴离子（O2.—）产生以及细胞超微结构的胁迫影响。结果表明,随着Cr6＋浓度的增加,总叶绿素、叶绿素a、叶绿素b和叶绿素a/b均呈下降趋势,Fo先升后降,Fv/Fm、Fm及Fv/Fo均逐渐降低;可溶性蛋白和谷胱甘肽（GSH）含量先升后降,抗坏血酸（AsA）含量逐渐下降;超氧化物歧化酶（SOD）活性逐渐下降,而过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性均呈先升后降趋势;O2.—产生速率、丙二醛（MDA）和可溶性糖含量均表现先降后升趋势;电镜观察发现：随着Cr^6＋浓度的增加,对细胞超微结构的损伤也加剧,表现为叶绿体膨胀,被膜破裂,类囊体片层解体;线粒体嵴数目减少,呈空泡状。可见,Cr6＋破坏了菹草正常生理活动的结构基础,造成菹草生理功能紊乱。

英文摘要：

The toxic effects of Cr^6＋ （0,1,10,30,50 mg·L^- 1 ） on chlorophyll, chlorophyll fluorescence parameters, antioxidant systems, soluble protein, lipid peroxidation, soluble sugar, active oxygen generation and ultrastructure changes in leaf of Potamogeton crispus were studied. The results showed that with increasing concentration of Cr^6＋ , the contents of chlorophyll, chlorophyll a, chlorophyll b and chlorophyll a/b decreased gradually, and Fo enhanced progressively up to 10 mg ·L^-1 Cr^6＋ and followed by a decline at higher dose. Fv/Fm, Fm and Fv/Fo decreased gradually. Soluble protein content and ascorbic acid（AsA） content enhanced and followed by a decline, glutathione （GSH） content decreased gradually. The activity of superoxide dismutase （SOD） decreased gradually, and activities of peroxidase （ POD）, catalase （ CAT）, aseorbate peroxidase （ APX）, glutathione reductase （GR） increased first and then decreased. While O2^-, MDA and soluble sugar content enhanced and followed by a decline. Transmission electron microscope observation indicated that Cr^6＋ also imposed injury action on ultrastructure of leaf cells, swelling of chloroplast and breakage of chloroplast envelope, decreasing of cristae quantity and vacuolization of mitochondria were observed. The conclusion could be reached that the plant death was resulted from destruction under structure foundation of physiological function, disorder of physiological metabolism.