VIEW ARTICLE

Physiology and Biochemistry

Factors Affecting Behavior and Developmental Synchrony of Germinating Oospores of Pythium aphanidermatum. D. M. Ruben, Graduate Research Assistant, Division of Plant Pathology, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel; Z. R. Frank(2), and I. Chet(3). (2)Research Associate, Division of Plant Pathology, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel; (3)Professor, Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot, Israel. Phytopathology 70:54-59. Accepted for publication 18 July 1979. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-54.

Germination of oospores of Pythium aphanidermatum was greatly stimulated by desiccation of cultures prior to spore isolation. Germination of oospores from desiccated cultures was induced with good synchrony following the application of two additional activating treatments: incubation in water for 5 min at 39 C and agitation in 0.1% KMnO₄ for 15 min. A synthetic liquid medium containing salts and lecithin was developed for synchronous indirect germination (production of zoospores from oospore hyphal germ tubes). In the absence of lecithin and when lecithin was replaced by other organic compounds in the medium, activated oospores germinated at a very low rate. Addition of glucose and other organic compounds to the liquid germination medium resulted in oospore germination without the production of zoospores (direct germination).