铜绿微囊藻对轮虫生命表参数和表型特征的影响

EFFECTS OF MICROCYSTIS AERUGINOSA ON THE LIFE-TABLE PARAMETERS AND PHENOTYPIC TRAITS OF ROTIFERS

为评价铜绿微囊藻的有毒(Microcystin-producing Microcystis aeruginosa)、无毒(Microcystin-free M.aeruginosa)品系对轮虫种群增长和表型特征的影响,研究探讨了萼花臂尾轮虫(Brachionus calyciflorus)在不同微囊藻溶液中的生活史参数及形态变化。实验中各处理组单位体积总含碳量为(20.61±0.15)g C/m L,以使轮虫获得等碳量的食物供应。实验组轮虫分别用蛋白核小球藻(Chlorella pyrenoidosa)、斜生栅藻(Scenedesmus obliquus)、有毒和无毒微囊藻溶液单独投喂,并用有毒、无毒蓝藻菌分别与不同绿藻的混合液投喂。生命表实验结果表明,不同微囊藻混合液投喂的轮虫净生殖率R_0(F=102.71,df=32,P<0.001)、世代时间T(F=17.05,df=32,P<0.001)和内禀增长率r_m(F=18.89,df=32,P<0.001)与对照组相比降低1.36%—210.34%。侧棘刺长(F=28.18,df=65,P<0.001)和游泳速度(F=181.69,df=65,P<0.001)下降2.63%—39.07%,轮虫体长(F=690.04,df=65,P<0.001)变化显著。与绿藻投喂的轮虫参数值相比,轮虫的生命表参数和表型特征变化规律随微囊藻溶液浓度改变。萼花臂尾轮虫受到铜绿微囊藻胁迫时,生长繁殖受到抑制并通过改变自身形态以抵御不利的生存环境。

To evaluate the effects of microcystin-producing and microcystin-free Microcystis aeruginosa on the population growth and phenotypic traits of rotifers, we discussed the responses of life history parameters and morphology of Brachionus calyciflorus to different M. aeruginosa solutions. In order to ensure that rotifers obtained food supply from same carbon content, the total carbon content was maintained at a level of（20.61±0.15） μg C/m L per unit volume in every treatment group. Rotifers were fed on Chlorella pyrenoidosa, Scenedesmus obliquus, microcystin-producing and microcystin-free M. aeruginosa, and mixtures of green algae with toxic and nontoxic cyanobacteria, respectively. Compared with the control group, the life-table experimental results showed that net reproduction rate R_0（F=102.71, df=32,P〈0.001）, generation time T（F=17.05, df=32, P〈0.001） and intrinsic growth rate r_m（F=18.89, df=32, P〈0.001） of rotifers decreased 1.36%—210.34% in the groups fed with different M. aeruginosa mixtures. Posterolateral spine length（F= 28.18, df= 65, P〈0.001） and swimming speed（F= 181.69, df= 65, P〈0.001） of B. calyciflorus declined2.63%—39.07%, and the rotifer body length（F=690.04, df=65, P〈0.001） changed significantly. The life table parameters and phenotypic traits of rotifers changed with concentrations of Microcystis solutions compared with those in groups fed with green algae. Under the stress of M. aeruginosa, the growth and reproduction of B. calyciflorus were inhibited, and its morphology changed to defend adverse living environment.