pH对鱼腥藻和普通小球藻生长竞争的影响

pH值是藻类生长环境的重要理化指标，它可以通过改变环境酸碱度和碳酸盐平衡系统及不同形态无机碳分配关系来影响藻类的生长。为揭示水体中常见藻类的生长过程及其与pH的相互关系，设置了6.0,7.0,8.0和9.0等4个pH梯度，通过室内实验模拟水体条件，研究不同pH条件下主要水华藻类--鱼腥藻（Anabaena sp.strain PCC）和常见淡水藻类--普通小球藻（Chlorella vulga）的生长和种间竞争。结果表明，无论是在单种培养还是在共同培养体系中，4个pH条件下两种藻类的最大生物量差异显著（P〈0.05），鱼腥藻和普通小球藻的最适pH均为9.0，其中单种培养时鱼腥藻和普通小球藻的最大生物量分别为4473.5×104，689.6×10^4 cells·mL-1；共同培养时鱼腥藻和普通小球藻的最大生物量分别为2798.0×10^4，296.5×10^4 cells·mL-1。竞争试验结果表明，pH对藻类种间竞争抑制参数能够产生显著影响，pH 7.0时普通小球藻对鱼腥藻的竞争抑制参数（β）最大，为12.91；鱼腥藻对普通小球藻的竞争抑制参数（α）则是pH 6.0时最大，为1.778。在4个pH条件下普通小球藻对鱼腥藻的竞争抑制参数（β）均大于鱼腥藻对普通小球藻的竞争抑制参数（α），与单种培养相比，鱼腥藻最大藻细胞数受到明显削弱，说明普通小球藻在竞争中占优势。因此，在水产养殖过程控制和精准培水技术研究，以及控制养殖水体富营养化的过程中，可以通过调节养殖水体pH值以及普通小球藻的浓度来控制鱼腥藻的生长。

Effect of pH on growth and competition of Chlorella vulga and Anabaenasp.strain PCC

Chlorella vulga is a common freshwater algae and Anabaenasp.strain PCC is one of the most common blue-green algae in eutrophication lakes. The pH value is an important physical and chemical indicator of algae growing environment. The growth of algae could be affected by pH value, carbonate balance system and Distribution of inorganic carbon. In order to know the growth of water bloom blue-green algae in eutrophication lakes and the relationship between algae growth and pH, the experiment was carried out to investigate the interspecies competition between Chlorella vulga and Anabaenasp.strain PCC at different pH value. The test set up 4 pH gradients at 6.0, 7.0, 8.0, 9.0. The results indicated that Chlorella vulga and Anabaenasp.strain PCC grew best at pH 9.0 both in the uni-culture system and the co-culture system. The maximal biomass of Anabaenasp.strain PCC was 4 473.5×10^4 cells·mL^-1 in uni-culture system and 2 798.0×104 cells·mL^-1 in co-culture system. While the maximal biomass of Chlorella vulga was 689.6×104 cells·mL^-1 and 296.5×104 cells·mL-1 accrdingly. The inhibition parameter of interspecies competition could be significantly influenced by pH（P〈0.05）. The maximal inhibition parameter of Anabaenasp.strain PCC against Chlorella vulga was found at pH 6.0 and the number was 1.778. The maximal inhibition parameter of Chlorella vulga against Anabaenasp.strain PCC was found at pH 7.0 and the number was 12.91. The inhibition parameters of Chlorella vulga against Anabaenasp.strain PCC were larger than that of Anabaenasp.strain PCC against Chlorella vulga at each pH, which meant that the inhibition effects of Chlorella vulga on Anabaenasp.strain PCC were stronger than that of Anabaenasp.strain PCC on Chlorella vulga. In aquaculture, therefore, we can adjust the pH value of aquatic water and the concentration of the ordinary Chlorella vulga to control algae growth, both in aquaculture process control, accurate water technology research, and process control of aquaculture water eutrophication.