摘要：
通过设定氮限制(1/2N,1/4N,1/8N,1/16N,1/32N)和磷限制(1/2P,1/4P,1/8P,1/16P, 1/32P),对1株来自三亚海域的热带利玛原甲藻(Prorocentrum lima)生长和产毒的影响进行研究.结果表明,低氮、磷水平严重限制P. lima生长,随着营养盐水平的降低,细胞产量、生长速率和单位体积叶绿素a含量等生长指标下降.对残留N、P营养盐检测分析的结果表明,N限制条件下,氮、磷残留量均很低(P< 1 μmol/L,N-NO3- < 1.3 μmol/L,N-NH4+ < 2.7 μmol/L);P限制条件下,磷残留量低(< 1 μmol/L),N-NO3- 残留量却随磷限制的增强而升高.P限制条件下,当NO3-与NH4+同时存在时, P. lima优先吸收NH4+.N、P限制对P. lima产毒影响显著,除了1/2P处理的冈田酸含量(13.02 pg/cell)与对照(13.18 pg/cell)几乎相等外,其余所有处理的冈田酸含量均有升高.冈田酸最高值出现在1/32P处理(42.16 pg /cell),稍高于N限制处理的最高值(1/32-N:41.30 pg/cell).研究表明,单位细胞冈田酸含量与生长速率呈负相关.%The data reported here focus on the response of a tropical strain of the dinoflagellate (Prorocentrum lima),isolated from South China Sea (Sanya),to nutrient stress induced by various levels of nitrogen (N) and phosphorous (P). Cultures of P. lima were utilized to assess changes induced by N-limited levels (1/2N,1/4N, 1/8N,1/16N and 1/32N) and P-limited levels (1/2P,1/4P,1/8P,1/16P and 1/32P) with respect to control nutrient conditions. Low N and P availability resulted in low cell yield,total growth rate and total chl a,showing decreasing values with increasing nutrient limitation. The analysis of residual N,P nutrient concentrations showed that residual nitrogen and phosphorous were low under N-limitation(P< 1μmol/L,N-NO3- < 1.3μmol/L,N-NH4+<2.7μmol/L),but nitrate relatively high compared to N-limited condition under P-limitation ,which increased as P levels became more limited. P. lima preferentially took up ammonium under P-limitation when ammonium and nitrate coexist. N,P had a significant effect on the production of P. lima (ANOVA,P <0.001). Okadaic acid (OA) concentration ranged from 13.02 to 42.16 pg/cell,it increased under all tested levels except 1/2-P. The highest OA cellular concentration measured (42.16 pg/cell) was obtained from 1/32P. These values were slightly higher than the highest OA concentration measured in N-limited conditions (1/32N,41.30 pg/cell). Strong negative correlations were found between OA cellular content and division rate.
