Cu^2＋对菱叶片生理指标及超微结构的毒理学效应分析

研究了不同Cu^2＋处理浓度（0、0.002、0.004、0.006、0.008 mmol·L^-1）对菱叶片叶绿素含量和叶绿素荧光参数、膜脂过氧化和抗氧化系统等的影响,并用透射电镜观察了其叶细胞超微结构的变化。试验结果表明：随着Cu^2＋浓度的增加：（1）叶绿素含量、Fv/Fo和Fv/Fm显著下降,Fo显著上升;（2）活性氧（AOS）产生速率、丙二醛（MDA）含量、过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性逐渐升高;超氧化物歧化酶（SOD）、游离脯氨酸（Pro）和可溶性糖含量显著下降;抗坏血酸（AsA）、还原型谷胱甘肽（GSH）和谷胱甘肽还原酶（GR）含量呈先升后降趋势,且始终高于对照;（3）电镜观察发现,Cu^2＋对叶片细胞器的超微结构特别是叶绿体、线粒体和细胞核造成严重损伤。以上结果表明,本试验过量Cu^2＋的胁迫破坏了菱正常生理生化活动,并造成功能紊乱,最终导致菱的死亡。

Phytotoxicity of Cu2+ on Physiolodical Indices and Ultrastructural Responses in Leaves of Trapa bispinosa Roxb.

The toxic effects of various concentrations of Cu~(2+) (0, 0.002, 0.004, 0.006, 0.008 mmol·L~(-1)) were studied on chlorophyll content,chlorophyll fluorescence parameters,lipid peroxidation,antioxidant system and ultrastructure changes in leafs of Trapa bispinosa Roxb.The results showed that with the rise of Cu~(2+) concentration in culture medium,(1)the chlorophyll contents and chlorophyll fluorescence parameters (Fv/Fo,Fv/Fm) decreased significantly,while Fo increased gradually.(2)generating rate of active oxygen(AOS),malondialdehyde(MDA) content and the activities of peroxidase (POD),catalase(CAT) as well as ascorbate peroxidase (APX) all increased gradually.Superoxide dismutase(SOD) activity,free proline(Pro) and soluble sugar contents increased markedly.While the contents of ascorbic acid(ASA),glutathione(GSH) and glutathione reductase (GR) activity enhanced progressively and followed by a decline at the higher doses.(3)Transmission electron microscopy observation indicates that the higher Cu~(2+) concentration,the more serious damages to the leaf cells,especially chloroplast,mitochondria and nucleus.Thus,the detriment effect of Cu~(2+) of Trapa bispinosa Roxb.was resulted from disorder of physiological,biochemical metabolism and disorder of physiological metabolism.