中文摘要：

通过对塔玛亚历山大藻（ATHK和AT-6藻株）、链状亚历山大藻（ACDH藻株）和微小亚历山大藻（AM-1藻株）的PSP毒素含量和组成以及它们分别对轮虫、黑褐新糠虾和鲈鱼存活影响的比较研究发现：塔玛亚历山大藻AT-6藻株不产生麻痹性贝毒毒素PSP，而塔玛亚历山大藻ATHK、链状亚历山大藻ACDH和微小亚历山大藻AM-1均产生PSP毒素，其总含量分别为19．74、5．395、5．57fmol／cell（2．60、0．36、1．61Pg STX eq／cell）。塔玛亚历山大藻AT-6对轮虫、黑褐新糠虾和鲈鱼这三种生物均没有不利影响；对于轮虫，塔玛亚历山大藻ATHK和链状亚历山大藻ACDH的96hL C50分别为：200和1200cells／ml，而微小亚历山大藻AM-1无不利影响；对于糠虾，塔玛亚历山大藻ATHK、链状亚历山大藻ACDH和微小亚历山大藻AM-1的96hLC50分别为7000、11000、16000cells／ml；对于鲈鱼，这三株藻的96hLC50分别为3700、4000、20000cells／ml。四株亚历山大藻对三种生物的毒性大小与其PSP毒素含量和组成无直接的相关关系，其毒性作用可能来自其他未知毒性物质。塔玛亚历山大藻ATHK不同组分分别对三种生物的毒性比较研究表明：藻细胞重悬液和藻液对三种生物的不利影响最为显著，去藻过滤液和细胞碎片对轮虫和鲈鱼没有明显影响，但糠虾的存活率有所下降；细胞内容物对轮虫和糠虾也无影响，但对鲈鱼的存活有一定影响。以上研究表明：不同亚历山大藻的毒性大小存在差别，其对不同生物的危害机制也不相同，除PSP毒素外，亚历山大藻可能还存在其他的毒性物质。

英文摘要：

Alexandrium species are major HAB （ harmful algal bloom ） members. To investigate the toxicity and its mechanism of Alexandrium species, PSP toxin compositions, the contents of four Alexandrium strains ： A. tamarense（ATHK,AT-6） ,A. catenella（ACDH） and A. minutum（ AM-1 ）, and their effects on rotifer Brachionus plicatilis, mysid Neomysis awatschensis and perch Lateolabrax japonicus were studied. The PSP toxin compositions and contents were analyzed using HPLC through 96-hour acute toxicity assay. The results show method. And the studies of effects were carried out that A. tamarense（AT-6） did not produce any PSP toxins, while all A. tamarense （ ATHK ） ,A. catenella （ ACDH ） and A. minutum （ AM-1 ） produced PSP toxin, and the PSP content of them was 2.60,0.36,1.61pg STX eq/cell, respectively. A. tamarense（ AT-6 ）did not show any adverse impact on the three organisms, while for B. plicatilis, the 96hLC50 of A. tamarense （ATHK） and A. catenella（ACDH） was 200 and 1200 cells/ml, respectively. But B. plicatilis was not affected by A. minutum （ AM-1 ）. For N. awatschensis, the 96hLC50 of A. tamarense （ ATHK ） , A. catenella （ ACDH ） and A. minutum （ AM-1 ） was 7000,11000,16000 cells/ml, respectively. For L. japonicus, the 96hLC50 of these three stains was 3700,4000,20000 cells/ml, respectively. The toxicities of these Alexandrium strains to the three organisms were not correlated to their PSP contents and compositions directly,indicating that other non-PSP toxic substances may have caused the toxicity. The toxicity of different fractions of A. tamarense ATHK culture to the three organisms was also compared and the results revealed that the culture and re-suspended algal cells showed strongest adverse effects on B. plicatilis, N. awatschensis and L. japonicus. Cell-free medium and cell fragments reduced the survival of the mysid, but had no adverse influence on the rotifer and the perch. The cell contents affected the survival of the perch, but had no deleteriou