不同温度下铜绿微囊藻和斜生栅藻的最佳生长率及竞争作用

Optimal Growth of and Competition Between Microcystis aeruginosa and Scenedesmus obliquus Related to Temperature

以温度为主要控制因子,研究了单独培养和按不同接种密度比混合培养下铜绿微囊藻(Microcystis aerugino-sa)和斜生栅藻(Scenedesmus obliquus)的生长状况。结果表明,在温度为7～35℃条件下,微囊藻比增长率随着温度的升高而增大,而栅藻增长率随着温度的升高先增大后减小。竞争体系对2种藻的比增长率均有影响,微囊藻在微囊藻与栅藻接种比例为10∶1的混合培养体系中增长最慢,栅藻则在微囊藻与栅藻接种密度比为1∶10的混合培养体系中增长最慢。不同温度条件下在2种藻不同接种密度比的混合培养体系中,微囊藻对栅藻的竞争抑制能力均大于栅藻对微囊藻的竞争抑制能力。藻种间的竞争抑制能力因温度的变化而得到不同程度的强化或减弱,铜绿微囊藻具有更强的竞争能力。

Growths of Microcystis aeruginosa and Scenedesmus obliquus as affected by temperature were observed in mono-culture and mixed-culture varying in inoculation density under controlled laboratory conditions.It was found that with the temperature varying within the range of 7-35 ℃,the specific growth rate of M.aeruginosa increased with the temperature,while that of S.obliquus rose first and then fell with 25 ℃ as its turning point.In the mixed culture,competition between the two algal species affected their growth rates,making them lower in the mono-culture,and in all the three mixed-culture experiments,the specific growth rate of M.aeruginosa was higher than that of S.obliquus.M.aeruginosa grew the slowest in the mixed culture 10∶1（Microcystis aeruginosa∶Scenedesmus obliquus） in inoculation ratio,whereas S.obliquus did in the mixed culture 1∶10 in ratio.In all the mixed-culture experiments,regardless of inoculation ratio and temperature,M.aeruginosa displayed stronger competitive inhibition than Scenedesmus obliquus did.The interspecific competitive inhibition,varied with the temperature,either intensified or weakened,but M.aeruginosa was always more competitive.