水鳖叶片对不同浓度Pb2+胁迫的生理和结构响应

co-composting of aniseed marc, filter mud

关键词:  水鳖  Pb²⁺胁迫  抗氧化系统  超微结构

Key words:  Hydrocharis dubia  Pb²⁺ stress  antioxidant system  ultrastructure

摘要:

研究了不同浓度Pb²⁺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Pb²⁺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、H₂O₂、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,Pb²⁺处理后,分子量为16.3kDa、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,Pb²⁺对水鳖叶片细胞的叶绿体、线粒体和细胞核造成严重损伤。Pb²⁺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。

Abstract:

Hydrocharis dubia individuals were transplanted and cultured under different concentrations of Pb²⁺ 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 ultrastructural changes in leaves were investigated. The results showed that with increasing concentration of Pb²⁺,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; O^-₂· generation rate,H₂O₂,MDA and soluble sugar content increased; SDS-PAGE revealed that Pb²⁺ reduced the amounts of polypeptides with apparent molecular weights 16.3kDa and 55.0kDa,while three polypeptides with apparent molecular weights 23.1kDa,75.8kDa and 94.0kDa disappeared with the increasing of Pb²⁺ concentration; transmission electron microscopy observation indicated that the higher Pb²⁺ 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 Pb²⁺ stresses,leading to the disorder of metabolic balance and finally causing the death of the plant.