UBC Theses and Dissertations
Biology of Typhula erythropus Fr. Koske, Richard E
The life cycle of Typhula erythropus was studied in the field and. in culture. An attempt was made to correlate observations from both and to explain the behavior of this organism in nature. The effect of temperature, pH, various carbon:nitrogen ratios, and nutrient concentration on mycelial growth, sclerotium formation, and basidiocarp production was examined. Vegetative growth, including sclerotium formation, was favored by temperatures above 10 C, high strength media, and a pH of 4-5. Basidiocarp production was maximal at lower temperatures, on low strength media, at pH 6, and at a low C/N ratio. The conditions for sclerotium germination were determined, and sclerotium viability was investigated. Sclerotia produced at 4 C did not germinate until exposed to 15-20.C. These heat activated sclerotia and sclerotia grown to maturity at 15 C germinated rapidly when incubated at k C on water agar. A low germination rate resulted when sclerotia were incubated at 15 C. The growth zone of T. erythropus basidiocarps is subapical. Expansion of the Typhula fructification occurs in the same manner as that in the common mushroom, Agaricus bisporus. A complex relationship between the particular stage of development of the organism and cultural conditions was evident. The interaction of environmental and nutritional factors was especially obvious during sclerotium formation in culture. T. erythropus appears to be facultatively homothallic. In the absence of a compatible mating strain, all nine monokaryotic isolates became dikaryotic. However, when crossed in all combinations, the monosporic isolates exhibited typical tetrapolar heterothallism. This ambivalence in mating is of rare occurrence in the fungi. Species identification in the genus Typhula is based on such characters as basidiospore measurements, basidiocarp dimensions, coloration, substrate, number of basidiocarps per sclerotium, and sclerotial anatomy. The stability of these features under various conditions has never been tested. Four isolates of T. erythropus were examined in culture, and the constancy of certain taxonomically important characteristics was noted. Basidiospore measurements, sclerotial micro-morphology, and the coloration of basidiocarps arising from sclerotia were stable features in all isolates. Other characteristics were variable.
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