ASEXUAL SPORULATION IN COPRINUS-CINEREUS - STRUCTURE AND DEVELOPMENT OF OIDIOPHORES AND OIDIA IN AN AMUT-BMUT HOMOKARYON

Coprinus cinereus strain AmutBmut is a homokaryon with mutations in bo th mating type loci. It produces asexual spores (oidia) in sticky liqu id droplets on specialized aerial structures (oidiophores). These oidi ophores have uninucleate cells and are organized as those of the monok aryon 5026 from which the strain derived, However, unlike in the monok aryon, oidiophores in strain AmutBmut are induced by light. Young oidi ophores are easily detected upon light induction and the process of oi diophore development is readily followed in this strain. Fully grown o idiophores consecutively give rise to short branches (oidial hyphae) t hat break up into two or occasionally three uninucleate oidia (arthroc onidia) until up to 200 oidia are collected at the tip of the oidiopho re. Mature spores are enclosed by a mucilage and a double-layered prim ary cell wall with hair-like structures except for the sides of former cell attachments. In a summary of our microscopic observations on dev eloping oidiophores and nuclear stainings we present a model showing t he successive steps of oidiophore and spore development.