CULTURE AND HETEROTROPHY OF THE FRESHWATER DINOFLAGELLATE, PERIDINIUM CINCTUM FA. OVOPLANUM LINDEMAN(1).

A defined minimal medium was developed for an axenic strain of Peridinium (Indiana Culture No. LB 1336). Thiamine, biotin, and vitamin B12 did not stimulate growth. Of 15 organic carbon sources tried in light, fructose, galactose, glucose, malate, malonate, and pyruvate enhanced growth but propionate retarded growth. In dark-grown cultures only media with succinate permitted growth above the survival level. Stimulation of growth by organic carbon sources was markedly pH dependent.