PHACOTUS LENTICULARIS (CHLAMYDOMONADALES, PHACOTACEAE) ZOOSPORES REQUIRE EXTERNAL SUPERSATURATION OF CALCIUM CARBONATE FOR CALCIFICATION IN CULTURE1,2

摘要: In nature, zoospores of the chlamydophycean genus Phacotus Perty usually have a calcified lorica. The only cultured species, lenticularis (Ehrenberg) Stein, did not readily calcify in artificial media. To overcome this deficiency, we developed an culture medium (N-HS) which formed mineralized loricae, as under natural conditions. Calcification (strain Krienitz 91/1) was achieved containing ionic concentrations found habitats (i.e. Lake Haussee and Stechlin), hard-water lakes Baltic District (Germany). N-HS contained extremely low phosphate high calcium magnesium compared with common media, but were similar to those lakes. Calcium carbonate dissolved up saturation concentration (saturation index = 1). Supersaturation by addition ultra-alkaline compounds (Na2SiO3 or NaOH). highest super-saturation had 118 supersaturated respect carbonate. that modified media less sodium (lower supersaturations), calcification observed. determine effects silicon on calcification, various other tested shown be ineffective. conclusion, depends directly degree supersaturation medium, fundamental mineralization pattern does not. Our study shows can triggered controlled