S. D. Garrett
Transactions of The British Mycological Society
Summary Plates of different nutrient agars were inoculated at ten equidistant points with Helicobasidium purpureum and incubated for two months at 25° C. ; the fungus colonies were buried in jars of soil for three to four months, and then tested for viability by inoculation of carrot seedlings. Survival was increased by raising the carbohydrate concentration of the medium, but depressed by excess of nitrogen. The optimum nitrogen requirement for survival increased with rise in carbohydrate content of the medium. Survival of colonies was correlated with the production of firm resilient sclerotia around the centre of the colony. The depressing effect of excess nitrogen upon production of sclerotia and survival of colonies is attributed to an increased density of mycelial growth, leading to reduction of carbohydrate level below that required for maturation of viable sclerotia.