Germination of Zygospores in Chlamydomonas

Abstract

STUDIES on the life-cycles of green algæ have frequently been considerably hampered by the difficulty of obtaining germination of the zygospores. This obstacle was encountered here during preliminary investigations to determine the possibility of using, for genetic studies, an isogamous, heterothallic strain of Chlamydomonas Moewussi Gerloff (isolated in 1948 from greenhouse sand by Drs. P. R. Burk-holder and L. Provasoli). Mature zygospores, which are dark green, with verrucose walls, remain dormant for an indefinite time, and only a low percentage of spontaneous germination is obtained after several weeks. Initially, no success in promoting germination was achieved by the use of a wide range of physical and chemical treatments. (Examples of treatments which have been successful in other algæ are reviewed by Bold¹.)