外源Mn(Ⅱ)对菹草(Potamogeton crispus L.)生长及其铁锰含量的影响

菹草(Potamogeton crispus L.)对于富营养化水体具有良好的修复作用，而锰可能是沉水植物菹草恢复过程中的营养限制性因子之一. 采用浅水湖泊(武汉汤逊湖和南湖)沉积物培养菹草，研究外源Mn(Ⅱ)对菹草生物量，w(总叶绿素)及铁、锰吸收量〔m(Mn)和m(Fe)〕的影响. 结果表明:Mn(Ⅱ)对菹草生长具有促进作用；添加Mn(Ⅱ)和不添加Mn(Ⅱ)的菹草上述各项指标值差异显著；无论是否添加Mn(Ⅱ)，菹草茎叶m(Mn)与m(Fe)均呈高度正相关，菹草对Fe和Mn的吸收未表现出拮抗作用，且在菹草生长周期内，其茎叶锰铁比〔w(Mn)/w(Fe)〕保持在0.03～0.07的较低水平，与陆生植物对Fe和Mn的吸收机制存在明显差异. 

Effects of Manganese Application on Potamogeton crispus L. Growth and Response of Iron and Manganese in Plants

Previous studies showed that the submerged plant Potamogeton crispus L. contributes considerably to eutrophication control and water body restoration. Manganese was probably one of the nutrition limiting factors in P. crispus growth. In this study, sediments from two shallow lakes, Tangxunhu Lake and Nanhu Lake, in central China''s Hubei province were used to cultivate P. crispus under pot culture conditions. Biomass, chlorophyll concentration, and contents of manganese and iron in the plant were measured. Some statistical analysis, including analysis of variance and correlation analysis, were employed to analyze the effects of manganese addition on P. crispus''growth. The results indicated that the application of manganese increased the biomass of P. crispus. Significant differences existed in the above indices after the application of manganese. Contrasted with the absorption mechanism of terraneous plants to iron and manganese, there was no antagonistic effect during the absorption process of manganese and iron by P. crispus. The manganese and iron contents in the plant were significantly correlated whether applying manganese or not, while the ratio of manganese to iron in the stem and leaves was relatively low, ranging from 0.03 to 0.07.