TWO NEW MEMBERS OF THE BLASTOCLADIACEAE. II. MORPHOGENETIC RESPONSES TO O₂ AND CO₂

Abstract

The development of Microallomyces dendroideus and Allomyces reticulatus was studied under various mixtures of O2, CO2 and N2. All thalli grown in broth or agar media in air produce abundant resistant sporangia but rarely produce any zoosporangia. In both fungi, the proportion of zoosporangia borne by the thalli increases as the oxygen level decreases. In addition, increased CO2 strongly stimulates resistant sporangium germination in M. dendroideus. Neither fungus grows in the absence of oxygen; therefore, they seem to be adapted for rapid multiplication in a microaerophilic niche.