环境pH值和假交替单胞菌对颗石藻的影响

Effects of environmental pH and Psuedoalteromonas sp. NPyS3 on the Pleurochrysis carterae

研究以浙江省象山港虾塘藻华中分离的一种颗石藻(Pleurochrysis carterae)为对象,比较了不同起始pH值(6.5、7.5和8.5)条件下颗石藻及其与紫菜藻际分离的假交替单胞菌Psuedoalteromonas sp.NPyS3共培养时颗石藻种群增殖特征及钙化情况。结果显示:1)环境pH值对颗石藻的生长具有极显著的影响(P<0.01),起始pH值为8.5的培养体系中颗石藻细胞密度最高,生长状况最好;pH值越低细胞密度越小;而且低pH值(6.5和7.5)会显著抑制颗石藻钙化(P<0.05);2)在3种起始pH值条件下,假交替单胞菌NPyS3均显著抑制颗石藻的生长与钙化,Two-way Anova分析表明菌对颗石藻的抑制作用远大于pH值对藻造成的影响。研究表明,环境pH值对颗石藻的生长与钙化都产生显著影响,碱性条件比较有利于其增殖和钙化;然而环境中拮抗生物因素对颗石藻生长及钙化的抑制远大于pH值降低等非生物因素的影响。

One Pleurochrysis carterae strain isolated from the shrimp pond bloom in Xiangshan, Zhejiang Province, was pure cultured and co-cultured with Psedudoalteromonas sp.NPyS3 from Pyropia yezoenesis under different pH （6.5, 7.5 and 8.5） mediums.The growth and calcification conditions of P.carterae were observed.The results showed that the environmental pH effected the growth of P.carterae significantly （P〈0.01）.The algae grew best in pH 8.5, which were inhibited greatly when the pH got lower.The algae calcification was inhibited by low pH （6.5, 7.5） （P〈0.05）, the lower the worse.In different pH conditions, the population mass and calcification of P.carterae were declined significantly when co-cultured with Pseudoalteromonas sp.NPyS3.Two-way Anova analy-sis indicated that the inhibition of algae caused by bacteria was much greater than that of the pH.The results suggested that the low en-vironmental pH could inhibit the growth and calcification of P.carterae significantly, however, the inhibition effects from biotic factors was much critical than from abiotic factors while there are antagonist microbes existed around.