【摘要】 根据２４ｈ半致死盐度值，测定了大型氵蚤两个种群的盐度上限．当直接从淡水移到较高盐度水中时，淡水种群和寡盐水种群的盐度上限分别为７．８‰和８．５‰；当逐渐提高盐度时，盐度上限分别达到１２．０‰和１３．２‰，为了确定大型氵蚤的最适盐度，在室内盐度１‰到７‰间，设４～５个盐度梯度测定这种氵蚤的内禀增长率ｒｍ，结果表明两个种群的ｒｍ值均以２‰时最高更多还原

【Abstract】 The upper salinity limit defined as TL 50 for 24 hours of two populations of Daphnia magna were tested. If they are transferred directly from the freshwater to the water with higher salinities, the lethal upper salinity limits for freshwater and oligohalobic populations are resulted as 7.8‰ and 8.5‰, respectively. If they are treated with gradually increasing salinity, the lethal upper salinity limits of them are 12.0‰ and 13.2‰, respectively. In order to determine the optimum salinity, the intrinsic increase rate of Daphnia magna has been studied in the laboratory under 4￣5 gradients of salinity between 1‰ to 7‰. The results revealed that the highest r m value occured in 2.0‰ both populations.更多还原