中文摘要：

首次对乌江中上游底栖硅藻和水环境因子间关系进行系统定量研究。对底栖硅藻和水环境因子进行主成分分析和相关分析。结果表明,总磷是影响底栖硅藻属种分布的第一显著因子。利用加权平均回归方法,计算出底栖硅藻属种对总磷指标响应的生态最佳值和忍耐值,提取出的Nitzschia frustulum（Kütz.）Grun.、Nitzschia fonticola Grun.、Nitzschiapalea（Kütz.）W.Sminth、Surirella angusta Kütz.Nitzschia amphibia Grun.等17种硅藻是乌江中上游河流富营养化发生的指示性属种。而Achnanthes minutissima Kütz.、Cymbella affinis、Diatoma vulagaris Bory、Navicula protracta（Grun.）Cleve等9种硅藻是乌江中上游中营养化水体的指示性属种,对较低营养水体有一定的指示意义。底栖硅藻指示性属种的提取对富营养化河流的治理和合理利用提供科学依据,为用硅藻监测、评价水质和建立河流水质监测体系提供理论基础。

英文摘要：

The relationship between the benthic diatoms and water environmental factors in the middle and upper of Wujiang River was studied quantitatively for the first time.The results showed that TP was the most important factors which affected the distribution of the benthic diatoms by Principal component analysis and correlation analysis.The TP optima and tolerance of diatoms were calculated using weighted average regress and species of Nitzschia frustulum（Kütz.） Grun.,Nitzschia fonticola Grun.,Nitzschia palea（Kütz.） W.Sminth,Surirella angusta Kütz.Nitzschia amphibia Grun.and so on were the indicators for the outbreak of rivers’eutrophication in the middle and upper of Wujiang River.While species of Achnanthes minutissima Kütz.,Cymbella affinis,Diatoma vulagaris Bory,Navicula protracta（Grun.） Cleve and so on were the lower river eutrophic indicators species.The indicators species of diatoms can support scientific foundation for treating the eutrophic rivers,for monitoring and estimating water quality and setting up monitor system.