一株底栖硅藻——双眉藻的优化培养

The optimal culture of benthic diatom (Amphora sp.),a tropical sea cucumber(Stichopu horrens) bait

双眉藻似mphorasp．）是糙刺参（Stichopushorrens）喜食的优良饵料。本文采用光密度法分别测定了该藻在光照强度28～149μmol／（m^2·s）、温度20～35℃、盐度25～45和氮质量浓度0～7500mg／L、磷质量浓度0-440mg／L、硅质量浓度0～1500mg／L以及氮磷硅多因子组合情况下的比生长速率，探讨了光照、温度、盐度和不同质量浓度的氮、磷、硅单因子及多因子组合对该藻生长的影响，以及该藻的最适生长条件。单因子试验结果表明，该藻在光照范围为35～149lamol／（m^2·s）时都能良好生长，最适光照为56～99rtmol／（m^2·s），低温时该藻生长缓慢，最适生长温度为25～30℃。Amphorasp．为广盐性，在盐度25～45都能较好生长，最适盐度为30～35。氮、磷、硅的最适质量浓度分别是750～7500mg／L、44mg／L和150mg／L，磷对该藻生长的影响比氮更显著。正交实验结果表明，氮、磷、硅的最佳质量浓度分别为75mg／L、44mg／L和150mg／L，最佳配比为2．4：1：3．4，与其他底栖硅藻的相应指标存在一定的差异，可能是物种和地域环境差异引起的，反映出该藻适应高温、强光特殊栖息环境的特征。

The aim of this paper is to initially determine the optimum growth conctmons of Amphora sp.And to timely meet the food needs of the tropical sea cucumber. The growth rate of the algae was measured by optical density method at different experimental culture conditions. Effects of light intensity, temperature, salinity and nu- trients （nitrogen, phosphorus, and silicon） on the growth rate of Amphora sp. were investigated. Both monofactor tests of five factors and orthogonal combinations of nitrogen, phosphorus, and silicon were conducted. The results of monofactor tests showed that Amphora sp. could grow well at 35-149 μmol/（m^2·s）, with the optimal Light inten- sity at 56-99μmol/（m^2·s）. The growth of the algae was very slow at very low temperature, and the best temperature was between 25 and 30℃. The algae, a euryhalinous species, grew well at salinity from 25 to 45 with the optimal salinity at 30-35. The favorable concentrations of nitrate, phosphate and silicate were about 75-7500, 44 and 150 μg/L, respectively. The effect of phosphorus on the growth of algae was more significant than that of the nitrogen. The orthogonal test showed that the optimum concentrations of nitrogen, phosphorus, and silicon were 75, 44 and 150 mg/L respectively, so the optimal concentration ratio of nitrogen, phosphorus, and silicon was 2.4：1：3.4. Com- pared with the general benthic diatoms, there were some differences in the corresponding indicators, which may be attributed to the differences in species and geographical environment. The results of this research reflected the characteristics of high temperature and strong light inhabitation of the algae.