湖沼における Pythium属(水生菌類)の生態学的研究

抄録

The genus Pythium(aquatic fungi)is distributed widely in Japanese lakes, occurring both in the water and the bottom mud. So far as the researches are concerned, the following characteristics may be given with regard to the condition of distribution of the genus Pythium. 1. The amount of zoospores of Pythium in lake water fluctuated seasonally. The feature of seasonal rhythm differend with different lakes. The maximum was observed in winter and the minimum in summer. 2. The vertical distribution of zoospores of Pythium differed seasonally. The zoospores were distributed homogeneously from the surface to the bottom layer during the circulation period and only in the epilimnion during the stagnation period. 3. The distribution of the genus Pythium had close relation to the lake types. They were distributed abundantly in harmonic lakes, while they were very rare in dystrophic and acidotrophic ones.