Synchronous sporulation during idiophase development in surface cultures of Rhizopus arrhizus (Fischer)

A method to obtain synchronous sporulation during idiophase development in liquid surface cultures of Rhizopus arrhizus Fischer in described and evaluated for use in studying metabolism associated with asexual sporulation. In this system growth and sporulation are effectively separated. The respiratory pattern indicates three metabolic phases. The first is associated with spore germination; the second, trophophase, with growth; and the third, idiophase, with sporulation. Synchronous sporulation and the occurrence of distinct metabolic phases are taken as indications of fairly uniform cell development in the surface cultures. A photographic method of estimating large numbers of fruiting structures on semisolid medium is also described.