Effect of Temperature on Growth Rate and Development of the Thermophilic Fungus Chaetomium Thermophile

SUMMARY

Rates of growth of seven strains of Chaetomium thermophile var. dissitum and one strain of C. thermophile var. coprophile were determined over a wide range of temperature by measurement of increase in colony diameter on Emerson YpSs Agar. After a lag phase, increase in diameter occurred at a constant rate. Growth rates and cardinal points differed among the strains. Ability to grow, form mycelial pigmentation, and produce immature and mature perithecia at extreme temperatures differed significantly among the strains for a given character, and within a strain for different characters. The range of temperature suitable for sexual reproduction was small and was much less than that for vegetative growth and pigmentation. The two taxonomic varieties differed significantly from one another in their responses to extreme temperatures, and one strain of variety dissitum had lower growth rates and more restricted morphogenetic capacity than other strains of the variety.