Studies on the Red Tide Dinoflagellates-V

On Polykrikos schwartzi, BÜTSCHLI

Abstract

Polykrikos schwartzi was obtained in axenic culture by micro-pipette washings. The organism prefers low salinity (Cl 9.0‰), and is sensitive to the pH of the surrounding water. The optimal pH is 8.5. In axenic culture, P. schwartzi needs vitamin B₁₂, biotin, and thiamine for growth. The addition of other vitamins does not increase further growth. The pattern of specificity toward B₁₂ analogues is similar to that of Escherichia coli 113-3. Nitrate, ammonium, and urea are utilized as nitrogen sources. The highest growth was obtained at the concentration of 0.3mg/l, of NH₄-N. Inorganic and organic phosphates are available for the organism. P. schwartzi can store excess phosphorus provided there are adequate supplies. The decomposed matters or the extracts of animal tissues, yeast, casein increase the growth remarkably. The result shows that the organism is an imperfect autotroph.