The Effects Of Different Nitrogen And Phosphorus Sources On The Growth And Toxin Production Of Prorocentrum Lima

Marine benthic dinoflagellate has some ecological properties different from phytoplankton dinoflagellate. Prorocentrum lima is a well known DSP toxins producing marine benthic dinoflagellate. In order to explore the nutrient properties of Prorocentrum lima and biosynthesis mechanism of DSP, the growth and activities of nitrate reductase and alkaline phosphatase of Prorocentrum lima were observed under different nitrogen and phosphorus sources. DSP toxin productions were also analyzed. Prorocentrum lima was showed to grow well under different conditions. The maximum growth rates (μ_max) were almost equal under different nitrogen sources. The maximum biomass(X) and nitrate reductase activity of Prorocentrum lima under nitrate and urea were all higher than those under ammonium as the nitrogen source. OA concentration per cell of Prorocentrum lima at the stable phase under nitrate was higher than those under ammonium and urea. The maximum growth rate (μ_max) was lower slightly underβ-sodium glycerophosphate than those under natrium biphosphoricum and adenosine triphosphate as phosphorus sources respectively. The maximum biomass(X) under adenosine triphosphate was higher than those under natrium biphosphoricum andβ-sodium glycerophosphate as the phosphorus sources. When the concentration of NaH₂PO₄ was below 2μmol·L^-1, the activity of alkali phosphatase increased significantly. However, the activities were much low in the all treatments whenβ-sodium glycerophosphate used as phosphorus source, whereas the activities increased with the concentration of ATP when ATP used as phosphorus source. The concentration of OA in Prorocentrum lima at the stable phase underβ—sodium glycerophosphate was higher than those under NaH₂PO₄ and ATP. These suggested that the three nitrogen sources and phosphorus sources could be utilized by Prorocentrum lima, and that urokinase be present in cell of Prorocentrum lima. The three nitrogen sources all could induce nitrate reductase.β-sodium glycerophosphate could be utilized directly by Prorocentrum lima, but the efficacy was lower; ATP could induce alkali phosphatase to produce inorganic phosphate for algae. DSP toxin contents in cells of Prorocentrum lima were different under various nutrition sources, and nitrate andβ-sodium glycerophosphate enhanced the highest DSP toxin content.