A correlation between rodlet orientation and conidiogenesis in Hyphomycetes

摘要

Freeze-etching has revealed changes in the orientation of rodlet fascicles on the surface of the outer wall layer of conidia and conidiogenous cells at successive stages of development. Specific patterns of rodlet fascicles reflect the progressive increase in cell volume and change in shape characteristic of 'blastic' conidium development inGonatobotryum apiculatum. Rodlet patterns over most of the wall surface of conidia ofOidiodendron truncatumandGeotrichum candidum, on the other hand, are not significantly different from the patterns of rodlet fascicles on the wall of the determinate, fertile hyphae from which the conidia arose. This latter structuralndash;developmental relationship is suggested to be characteristic of the 'arthric' mode of conidiogenesis. It is demonstrated, however, that conidium formation inOidiodendron truncatumdoes involve some meristematic activity in addition to conversion and disarticulation of pre-existing hyphal elements. A diagrammatic interpretation of these changes in rodlet patterns during conidiogenesis is presented.