Physiological and morphological variation in Oidiodendron majus

摘要

A collection of 22 isolates of the hyphomycete Oidiodendron maius from soil, peat, wood, and ericoid mycorrhizas in northern Europe and North America was examined using 16 simple physiological tests, SEM, and light microscopy. Twenty-one of the isolates were similar in gross cultural morphology, in being uniformly acidophilous, in their intolerance to high salt concentrations, and in having temperature optima around 20-25 degreesC. SEM examination of conidia showed that although shape could vary substantially within a single chain, surface ornamentation was uniform among the isolates and because of fine asperulations on a perispore membrane. Conidiophore length, traditionally relied upon for species determinations in the genus, was too variable among the isolates to be a definitive character. The morphological, physiological, and ecological features examined did not indicate that subspecific taxa occur within O. maius. An isolate that had been included due to a previous misidentification, showed substantial physiological differences from the other 21 O, maius isolates. In addition to fine differences in culture, this isolate also had a unique conidial perispore confirming its lack of taxonomic relationship to the other isolates. [References: 23]