Ultrastructural aspects of conidiogenesis in Gonatobotryum apiculatum

Abstract

Conidium formation in Gonatobotryum apiculatum (Peck) Hughes is identified as holoblastic (Kendrick 1971. Taxonomy of Fungi Imperfecti. University of Toronto Press). Morphological features of this developmental process are demonstrated using scanning and transmission electron-microscopic and freeze-etch techniques. The wall relationships between scars (denticles) on the surface of conidiogenous cells and basal abstriction scars of conidia are demonstrated. The presence of cytoplasmic deposits of insoluble polysaccharides and crystalloids in the apex of conidiogenous cells are noted and possible functions of these inclusions are discussed. "Paramural bodies" (Marchant and Robards 1968. Ann. Bot. 32: 457) in conidiogenous cells are also described. A diagrammatic interpretation of conidiogenesis in this species is presented.