水鳖叶片对不同浓度Pb^(2+)胁迫的生理和结构响应  

Physiological and structural responses of Hydrocharis dubia leaves to different concentrations of Pb^(2+) stress

作　　者：丁春霞[1] 施国新[1] 徐勤松[1] 杨海燕[1] 许晔[1] 徐小颖[1] 

机构地区：[1]南京师范大学生命科学学院江苏省生物多样性与生物技术重点实验室,南京210046

出　　处：《广西植物》2009年第6期768-773,共6页Guihaia

基　　金：国家自然科学基金(30670121;30870139);高等学校博士学科点专项科研基金(20050319005)~~

摘　　要：研究了不同浓度Pb^(2+)胁迫(0、10、20、30和50 mg·L^(-1))对水鳖叶绿素含量、可溶性蛋白含量、抗氧化系统、活性氧产生速率和细胞超微结构的影响。结果表明:随着Pb^(2+)浓度的增加,水鳖叶片总叶绿素、叶绿素a/b值、可溶性蛋白含量和CAT活性逐渐下降;SOD、POD、APX、GR活性、抗坏血酸(AsA)和谷胱甘肽(GSH)含量先升后降;O_2^-·产生速率、H_2O_2、丙二醛(MDA)和可溶性糖含量呈上升趋势;不连续聚丙烯酰胺凝胶电泳(SDS-PAGE)显示,Pb^(2+)处理后,分子量为1 6.3kDa、55.0kDa的多肽含量减少,高浓度处理下分子量为23.1kDa、75.8kDa、94.0kDa的多肽条带消失;电镜观察发现,Pb^(2+)对水鳖叶片细胞的叶绿体、线粒体和细胞核造成严重损伤。Pb^(2+)破坏了水鳖正常代谢所需的生理和结构基础,打乱了代谢平衡,最终导致植物的衰亡。Hydrocharis dubia individuals were transplanted and cultured under different concentrations of Pb^2＋ stress （0,10,20,30 and 50 mg · L^-1 ） for 7 days. After that, the chlorophyll content, soluble protein content, antioxidant system,active oxygen generation and ultrastruetural changes in leaves were investigated. The resuhs showed that with increasing concentration of Pb^2＋ , the chlorophyll content, chlorophyll a/b,soluble protein content and CAT activity decreased ; SOD, POD, APX, GR activities, AsA and GSH content increased at first and then decreased ; O2-· generation rate, H2O2, MDA and soluble sugar content increased; SDS-PAGE revealed that Pb^2＋ reduced tile amounts of polypeptides with apparent molecular weights 16.3kDa and 55.0kDa,while three polypeptides with apparent molecular weights 23.1 kDa, 75.8kDa and 94.0kDa disappeared with the increasing of Pba＋ concentration; transmission electron microscopy observation indicated that the higher Pb^2＋ concentration,the more serious damages the chloroplast,mitochondria and nucleus suffered. It was concluded that physiological and structural foundations in the normal metabolism of Hydrochairs dubia would be destructed by Pb^2＋ stresses,leading to the disorder of metabolic balance and fiually causing the death of the plant.

关 键 词：水鳖 Pb^(2+)胁迫 抗氧化系统 超微结构 

分 类 号：Q945.8[农业科学—植物病理学]