丙酮对小球藻和水华微囊藻的生长及叶绿素荧光参数的影响

Effects of Acetone on Growth and Chlorophyll Fluorescence Parameters of Chlorellavulgarisand Microcystis flos-aquae

以小球藻和水华微囊藻细胞的生长状况、光合作用参数、叶绿素a质量浓度的变化作为指标,研究不同体积分数的丙酮对2种藻类的毒性效应.结果表明:体积分数为0.000 5%~0.500 0%的丙酮对小球藻和体积分数为0.000 5%~0.050 0%的丙酮对水华微囊藻均不同程度地促进藻细胞生长,对藻类的叶绿素a无影响,明显提高了藻类的最大光合速率(rETRmax)、光能利用率(α)和光适应能力(Ik),同时提高了光系统Ⅱ的最大光化学效率(Fv/Fm);丙酮体积分数为5.000 0%的小球藻和丙酮体积分数为0.500 0%~5.000 0%的水华微囊藻,其藻类光合作用、叶绿素a显著降低,导致藻类生长严重抑制甚至死亡;丙酮对小球藻和水华微囊藻的最大无影响体积分数(NOEC)分别为0.500 0%,0.050 0%,说明水华微囊藻对丙酮更为敏感.

The toxic effects of different volume fractions of acetone on algae were studied, using the growth condition, photosynthetic parametersrs, chlorophyll a mass-concentration of Chlorella vulgaris and Microcystis flos-aquae as indexes. The results showed that 0.000 5%-0. 500 0% and 0.000 5% -0.050 0% volume frac-tions of acetone respectively were in varying degrees to promote Chlorella vulgaris and Microcystis flo s -aqu a e growth. Both concentration ranges had no significant effect on the chlorophyll a of algae, while increased the maximum photosynthetic rate （rETRmax） , the solar energy utilisation efficiency （a） and the tolerance of algae to strong light （Jk） significantly, as well as improved the photosystem H photochemical efficiency （Fv/Fm）. When the Chlorella vulgaris was at 5. 000 0% acetone volume fraction and Microcystis flo s -a qu a e at 0. 500 0% to 5. 000 0% acetone volume fractions？ algae photosynthesis and chlorophyll a were reduced obviously, which resulted in severe algal growth inhibition and even death. The corresponding NOEC of acetone was 0. 500 0% for Chlorella vulgaris and 0. 050 0% for Microcystis flos - a quae, indicating that Microcystis flos-aquae was more sensitive to acetone than Chlorella vulgaris.