不同磷条件下接种配比对两种淡水藻生长的影响

研究了不同磷浓度条件下铜锈微囊藻和斜生栅藻在单独培养和按不同接种密度比混合培养时的生长状况，分别计算了各培养条件下两种藻的磷吸收半饱和常数。结果表明：在试验所设置的磷浓度范围内，两种藻增长速率均随着磷浓度的升高而增大，但是磷浓度变化对铜锈微囊藻的影响较栅藻小。在磷浓度低于100 μg/L时，1〖DK〗∶1共培养体系中微囊藻的增长速率大于栅藻，而磷浓度大于100 μg/L时，结论相反。接种密度比对两种藻的最大密度和增长率均有影响，微囊藻的增长率随着接种密度比减少而增大，栅藻则相反。铜锈微囊藻在10〖DK〗∶1共培养体系中增长最慢，栅藻则在10〖DK〗∶1共培养时增长最快。微囊藻半饱和常数随着在接种密度中所占份额的减少而减小，最小为1035 μg/L，栅藻则没有显示明显规律，在1〖DK〗∶10共培养体系中磷饱和常数最小，为1982 μg/L。无论在哪种培养体系中，铜锈微囊藻的磷吸收半饱和常数均小于斜生栅藻，表明微囊藻对磷营养盐更具亲和性，营养盐浓度较低的环境下微囊藻更易在竞争中获胜。

DYNAMICS OF MICROCYSTIS AERUGINOSA AND SCENEDESMUS OBLIQUUS IN CULTURE SYSTEMS WITH DIFFERENT PHOSPHORUS CONCENTRATION

The specific growth of 〖WTBX〗Microcystis aeruginosa〖WTBZ〗 and 〖WTBX〗Scenedesmus obliquus〖WTBZ〗 was studied on the condition of pure culture and different mixed cultures with different phosphorus concentration in laboratory，and P half saturation constant of each algae in different culture conditions was calculated.As a result，within the setting scope of phosphorus concentration，it is shown that the growth rates of the two algae both became greater as raising phosphorus concentration，with a greater influence on Scenedesmus obliquus〖WTBZ〗 than on 〖WTBX〗Microcystis aeruginosa〖WTBZ〗.The growth rate of 〖WTBX〗Microcystis aeruginosa〖WTBZ〗 was greater than that of 〖WTBX〗Scenedesmus obliquus〖WTBZ〗 in 1〖DK〗∶1 mixed culture when phosphorus concentration is lower than 100 μg/L；the facts pointed to a contrary conclusion if the phosphorus concentration was higher than 100 μg/L.Both the growth rates and the maximum amounts of the two species were affected by different inoculation densities-the growth rates of Microcystis aeruginosa increased with the decrease of inoculation densities while Scenedesmus obliquus〖WTBZ〗 had a contrary law.Scenedesmus obliquus got the maximum specific growth rate in the 10〖DK〗∶1 mixed culture，and Microcystis aeruginosa was at its minimum specific growth rate in the 101 mixed culture.P half saturation constant of 〖WTBX〗Microcystis aeruginosa decreased with the reduction of its proportion and got a minimum value of 1035 μg/L，but the P half saturation constant of 〖WTBX〗Scenedesmus obliquus did not show a distinct law，the constant getting the minimum value of 1982 μg/L in the 1〖DK〗∶10 mixed culture.No matter which culture system was used，P half saturation constant for Microcystis aeruginosa growth was lower than that of Scenedesmus obliquus〖WTBZ〗.So 〖WTBX〗Microcystis aeruginosa is easier to win in the competition in comparative low nutrition environment.