Gametogenesis in liquid cultures of Chlamydomonas eugametos

Plantenfysiologisch Laboratorium, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, Holland ABSTRACT Summary: At the end of the exponential phase of vegetative growth in liquid cultures, cells of Chlamydomonas eugametos develop into gametes. Gametogenesis can occur without nitrogen deficiency. In continuous light, mating competence lasts only for a few hours, resulting in a low percentage of gametes. Nevertheless, mating competence is considered to be a general property of newly born cells in late exponential phase, since cultivation of both mating-types in mixed cultures normally leads to a high yield of paired cells. No evidence was found for an influence of the presence of partner gametes on gametogenesis. During gametogenesis of the mt - mating-type, extractable biologically active agglutination factor appears in the cell body. Subsequently, after a gametogenic division, mating competence and agglutinability are expressed, both fluctuating synchronously with the light/dark regime.