Effects of 15% CO2 on germination, germ tube elongation, and sporulation in cultures of Colletotrichum lindemuthianum

Abstract

Germination of conidia in cultures of the beta and gamma races of Colletotrichum lindemuthianum growing on bean juice agar was delayed in 15% CO2, though the proportion of conidia that finally germinated under these conditions was similar to the proportion that germinated in cultures maintained in air. Germ tube elongation in CO2 was inhibited during the early stages of development, but vegetative growth was ultimately stimulated under these conditions. Sporulation of cultures maintained in CO2 was delayed and fewer conidia were formed than in cultures maintained in air.The results suggest that there is an interrelationship between vegetative growth and spore production. The implications of these results to previous work on the effects of 15% CO2 on the host–parasite interaction between C. lindemuthianum and Phaseolus vulgaris are discussed.