不同氮磷比率对青岛大扁藻、新月柱鞘藻和米氏凯伦藻生长影响及其生存策略研究

在不同氮磷比(N：P=1：1，4：1，16：1，80：1，160：1)条件下，对青岛大扁藻(Platymonas helgolandica var．tsingtaoensis)、新月柱鞘藻(Cylindrotheca closterium)和米氏凯伦藻(Karenia mikimotoi)3种浮游植物进行了培养，对其生长特性进行了比较研究．结果表明，不同氮磷比例对其生长有明显的影响，新月柱鞘藻在N：P=160：1时细胞比生长速率最快，而青岛大扁藻和米氏凯伦藻分别在4：1和80：1的条件下比生长速率最快．单位水体中细胞丰度的多少主要受细胞体积大小和自身比生长速率的影响．细胞内叶绿素a的合成浓度明显受氮的影响。高氮磷比例有利于叶绿素a的合成，细胞内可溶性蛋白质含量对不同氮磷比例有明显反应，且其含量多少与细胞大小和生长周期密切相关．3种浮游植物相对来说，新月柱鞘藻属于生长快速的r选择物种，而青岛大扁藻和米氏凯伦藻则为有较强适应环境能力的K选择物种．

Growth of Platymonas helgolandica var.tsingtaoensis,Cylindrotheca closterium and Karenia mikimotoi and their survival strategies under different N/P ratios

In this study, laboratory culture experiments were carried out in a batch culture system, with the focus on the effect of different N/P ratios (1:1, 4:1, 16:1, 80:1 and 160:1) on the growth of Platymonas helgolandica var. tsingtaoensis, Cylindrotheca closterium and Karenia mikimotoi. The cell abundance, growth rate, and chlorophyll a and protein contents were measured every 24 h for one week. The results showed that N/P ratio significantly affected the growth of three kinds of algae. Cylindrotheca closterium grew fastest under 160:1 N/P ratio, while Platymonas helgolandica var. tsingtaoensis and Karenia mikimotoi grew fastest under 4:1 and 80:1 N/P ratio, respectively. The maximum cell density of the phytoplankton was mainly influenced by cell size and specific growth rate, the synthesis of chlorophyll a was mainly affected by nitrogen, and high N/P ratio benefited the increase of chlorophyll a content. The protein concentration in cells correlated significantly with N/P ratio, cell size and cell period. As for survival strategy, Cylindrotheca closterium showed obvious features of fast-reproductioned r-selective species, whereas Platymonas helgolandica var. tsingtaoensis and Karenia mikimotoi were most likely to be the more competitive K-selected species.