中文摘要：

利用共培养系统研究了在不同光照强度、生物量条件下，大型海藻龙须菜（Gracilaria lemaneiformis）及其水溶性抽提液对两种海洋赤潮藻旋链角毛藻（Chaetoceros curvisetus）和椎状斯氏藻（Scrippsiella trochoidea）的生长抑制效应．结果显示，龙须菜和两种赤潮藻问存在着营养竞争，受龙须菜的影响，两种赤潮藻的最大密度与对照组相比均有所下降，其受抑制程度随着龙须菜起始密度的增大而增强，而两种赤潮藻对龙须菜生长的影响却不显著．此外，龙须菜和两种赤潮藻之间还存在着光竞争，弱光条件更适合龙须菜的生长，强光条件下龙须菜对两种赤潮藻的抑制作用减弱．此外，龙须菜水溶性抽提液也会对两种赤潮藻的生长产生抑制．

英文摘要：

Inhibitory effects of Gracilaria lemaneiformis on the growth of two red tide microalgae Chaetoceros curvisetus and ScrippsieUa trochoidea were studied in coexistence culture systems. Results showed that G. lemaneiformis had obvious inhibitory effects on the growth of these two red tide microalga. The maximum cell densities of C. curvisetus and S. trochoidea decreased,and the inhibition effect was positively related to the initial biomass of G. lemameiformis. While,the two microalgae had little effects on growth of G. lemaneiformis. Illumination competition h.as existed between G. lemaneiformis and these two red tide micoroalgae. G. lemaneiformis was more propitious to grow in the weak illumination. Under the strong illumination, the inhibitory effects of this seaweed on two microalgae was decresed. In addition, the water - solubility extracts of G. lemaneiformis had obvious inhibitory effects on the growth of the red tide microalga.