Ascospores, Germ Pores, Ultrastructure, and Thermophilism of <i>Chaetomium</i>

Abstract

SUMMARYAscospores of IS isolates of Chaetomium thermophile were compared with those of 105 other Chaetomium species by use of light microscopy and scanning electron microscopy. Two stable characteristics distinguished C. thermophile ascospores from those of all other Chaetomium species examined: a papillate germ pore and pustulate surface ornamentation. Transmission electron microscopy revealed multilayered walls in ascospores of C. semen-citrulli and C. thermophile. In addition, germ pores were confirmed as thin areas in ascospore wall layers. Germinated ascospores of C. semen-citrulli contained several nuclei, mitochondria, fibrillar bundles, vacuoles, and glycogen-like particles.