占春池における水生菌類の季節的変化

抄録

1. The seasonal variations of the zoospores of aquatic fungi were studied from July 1955 to June 1956 in Senshun-ike Pond, Tokyo, Japan.
2. The amounts of the zoospores of aquatic fungi varied seasonally with two maxima and two minima. The maxima appeared in spring and autumn, and the minima appeared in summer and winter. The zoospores were counted 911/10cc in the maximum peridos and 32/10cc in the minimum periods. The water temperature of both maximum periods were 1520°C and 912°C respectively.
3. Ten species were isolated from Senshun-ike. They showed different seasonal changes. Achlya flagellata and Pythium sp. were seen throughout a year, while Achlya racemosa and Apodachlya brachynema were obtained only in winter. Aphanomyces laevis and Saprolegnia sp. prefered to the high temperature season.
4. The production of the zoospores of aquatic fungi was much influenced by the water temperature as well as by the prosperity and decay of lacustrine bacteria.The temperature curve was drown from the data obtained at Senshun-ike Pond. The curve showed that the production of the zoospores took place by the step wise with the rise of the water temperature.
5. The optimum temperature for the formation of the zoospores in some species was as follows:
Saprolegnia monoica 318°C
Achlya racemosa 312°C
Achlya flagellata 921°C
Aphanomyces laevis 1518°C
Apodachlya brachynema 45°C