Effect of strontium replacement for calcium on production of motile cells in Protosiphon.

Protosiphon botryoides Klebs grows without evident zoosporogenesis in inorganic media in which strontium is substituted for calcium. Growth is 50 to 90 percent of that obtained with calcium; when sodium is substituted for calcium, there is no appreciable growth. Motility was observed at or above CaCl(2). 2H(2)O levels of 5 mg/lit., with or without strontium.