中文摘要：

通过实验生态学的方法，分别以KNO3和KH2PO4为氮源和磷源，研究青岛大扁藻（Platymonas helgolandicavar．tsingtaoensis）和牟氏角毛藻（Chaetoceros muelleri Lemmerman）单培养和共培养时的生长状况。结果显示，不同氮磷处理对两种藻的单培养和共培养都有显著影响（P〈0．05）。共培养时，青岛大扁藻的最大藻密度与氮磷浓度呈正相关。氮处理时，当培养液中KNO，为110mg／L时，取得最大值；磷处理时，青岛大扁藻的最大藻密度在KH2PO4为9mg／L时取得最大值；而牟氏角毛藻分别在KNO3为70mg／L和KH2PO4为5mg／L时取得最大值。共培养时两种藻的藻密度都低于单培养。另外．无论低氮高磷还是高氮低磷都不利于两种藻获得较大的终细胞密度。

英文摘要：

It was designed to examine the effects of different concentrations of nitrogenous and phosphorus on growths of mixed cultures and monocultures of Platymonas helgolandica var. tsingtaoensis and Chaetoceros muelleri Lemmerman. Results showed that the growth of Platymonas helgolandica var. tsingtaoensis and Chaetoceros muelleri Lemmerman in different treatments was significantly different （ P 〈 0. 05）. When mixed culture, the max algae densities of Platymonas helgolandica var. tsingtaoensis had positive relationship with nitrogenous or phosphorus concentration. When the concentration of KNO3 was 110 mg/L or KH：PQwas 9 rag/L, the max algae density of Platymonas helgolandica var. tsingtaoensis got to biggest value, compared to that of Chaetoceros muelleri Lemmerman reached the top when the concentration of KN03 was 70 mg/L or KH2PO4 was 5 mg/L. The algae density of mixed culture of Platymonas helgolandica var. tsingtaoensis and Chaetoceros muelleri Lemmerman was lower than that of Platymonas helgolandica var. tsingtaoensis and Chaetoceros muelleri Lemmerman cultured alone. Otherwise, in low nitrogen high phosphorus or in high nitrogen low phosphorus, the last algae density of Platymonas helgolandica var. tsingtaoensis and Chaetoceros muelleri Lemmerman was lower than the others.