中文摘要：

为明确渭河杨凌段浮游硅藻植物群落的特点及生态类型,对采集自杨凌示范区水域的样品进行了显微镜观察,共鉴定到硅藻门植物44个分类单位,包括27种14变种2变型,分别属于2纲6目9科20属,其中优势种有平片针杆藻、梅尼小环藻、小型异极藻具领变种、小型异极藻椭圆变种.小型异极藻具领变种数量最多,是构成浮游植物的主要组成类群,是渭河杨凌段的优势种类.渭河杨凌段浮游植物生物量大,多样性状况较差.

英文摘要：

Through analysis of the samples from Yangling Reach of Weihe River by microscope, diatoms community and ecological form were es- timated. The investigation showed that there were 44 species belonging to 2 classes ,6 orders ,9 families ,20 genera ,27 species, 14 varieties and 2 forms in Yangliug Reach. Synedra tabulata （Ag） Kuetz, Cyclotella meneghiniana Kuetz, Gomphonema parvulum vat. lagenula（ Kuetz ） Frenguelli and G. parvulum var. subellipticum Cleve were the dominant phylum. The plentiful species, G. parvulum var. lagenula was dominant in the phyto- plankton community. Phytoplankton biomass was high,diversity status was not good.