中文摘要：

1材料与方法 根据2003年夏秋两季分布在我国热带和亚热带部分地区22个样点（其中现存水蕨种群type A原产地12个，绝迹水蕨种群type B原产地10个）的22个水化学参数（Cu、Ca、Mg、Fe、Mn、总磷、pH值、溶解氧、硬度、酸度、碱度、Br、NH3-N、Cl、Cr^6＋、Mo、Ni、NO3-N、PO4^3-、Zn、溶解CO2、电导率）的平均值，计算其变异系数。对具显著性差异的两个化学因子分别采用最小显著差法和相关系数法进行多重比较分析和相关性分析。

英文摘要：

[ Objective] This study was to analyze the two hydrochemical factors affecting the distribution of Ceratopteris thalictroides, further to provide basis for its habitat protection and population restoration. [ Method ] Twenty two hydrochemical parameters of 22 sampling sites in China＇s tropical and subtropical zones were respectively averaged for calculating their variation coefficients, of which the two showing significant differences were used for multiple comparisons and correlation analyses via least significant difference and correlation coefficient. E Result ] The correlation coefficients of all the 22 tested hydrochemical parameters varied hugely, but only pH value and conductivity showed significantly differences in two water body （type A and type B）. Analysis of correlation presented that pH value were positively correlated with conductivity; further the multiple comparisons showed that the significant difference of pH value was higher than that of conductivity. [Conclusion] With regard to the two hydrochemical parameters showing significant differences, pH value influences the distribution of C. thalictroides more.