水生生物学报2009，Vol.33Issue(4)：613-619,7.DOI:10.3724/SP.J.0000.2009.40613
Zn对荇菜叶片保护酶活性、渗透调节物质含量和Ca2+定位分布的影响
EFFECT OF ZN ON PROTECTIVE ENZYMES ACTIVITY,OSMOLYTES CONTENT AND CA2+ DISTRIBUTION IN LEAVES OF NYMPHOIDES PELTATUM
摘要
Abstract
Zinc (Zn) is an essential microelement for normal growth and development of plants at low concentration ; however, it is also an important environmental pollutant due to anthropogenic pressure as well. In the present study, Nymphoides peltatum, a rooted-floating aquatic macrophyte, was cultivated with elevated concentration of Zn (0,5,10,15 and 20mg/L) for 9d respectively. The response of activities of superoxide dismutase (SOD) and peroxidase (POD), osmolytes (proline and soluble sugar) to Zn stress was investigated and Ca2+ ultrastructural distribution in leaf cells was examined with the cytochemical method of calcium antimonate precipitation. The results indicated that Zn decreased SOD activity by 11.46%-75.22% and the inhibition action reached significant level (R = - 0. 8642, p ＜ 0.05) compared with that of control ; while it stimulated POD activity and increased by 2.55--3.89 fold over that of control; in response to Zn pollution, N. peltatum exhibited a enhancement in proline level and increased by 49.93%--142.31% in comparison to control ; the same tendency was also recorded in soluble sugar level under Zn stress, its accumulation showed progressive increase with the rise of external Zn concentration and enhanced by 13.83% to 100.64% , respectively. Electron microscope observation showed that Ca2+ mainly distributed within intercellular space and vacuole, some calcium deposits could be randomly found in cytoplasmic matrix and nucleus under normal conditions, when different dose of Zn was added into the culture solution, and the calcium level in these compartments lowered while that in cytoplasm increased remarkably, especially bigger particles of calcium deposits appeared at the inner aspect of plasmalemma and cell nucleus, which might be attributed to the opening of the calcium channels in plasmalemma and tonoplast and the loss of activity of the Ca2+ pump, this, in turn further enhanced the calcium level of cell interior. The rise of Ca2+ level in cytoplasm and cell nucleus maybe related to the changes of a series of physiological and biochemical processes. The dense distribution of Ca2+ in inner aspect of plasmalemma and in cell nucleus might lead to the damage to the plant cell or the death in the end. Based on observations in the present investigation, it can be concluded that several defense systems are activated simultaneously when affected by Zn, including the induction of stress enzymes (POD), increase of synthesis or content in osmolytes (proline and soluble sugar) and changes in the distribution and content of loosely-bound Ca2+.关键词
Zn/荇菜/SOD/POD/脯氨酸/可溶性糖/Ca2+/应答Key words
Zn/Nymphoides peltatum/SOD/POD/Proline/Soluble sugar/Calcium/Response分类
农业科技引用本文复制引用
徐勤松,施国新,计汪栋,杜开和,许晔..Zn对荇菜叶片保护酶活性、渗透调节物质含量和Ca2+定位分布的影响[J].水生生物学报,2009,33(4):613-619,7.基金项目
国家自然科学基金(30800055) （30800055）
江苏省教育厅自然科学基金(05KJB180067) （05KJB180067）
南京师范大学科研启动基金(2005104XGQ2B73) （2005104XGQ2B73）
高等学校博士学科点专项科研基金课题(20050319005)资助 （20050319005）
