アカマツ林土壌における糸状菌の分布に関する研究(第6報) : 有機物層の糸状菌の季節変動

The seasonal fluctuations of micro-fungi in F layer of pine forest(Pinus densiflora) were examined for information about the ecological characters of each member of microfungus population.
Studies were made in June 30, September 7 and November 15,1967.
Eighteen samples were taken in a stand in order to know the spatial variation within a stand and to allow a seasonal comparison.
Micro-fungi were isolated by the usual dilution plate method.
As shown in Fig. 1, frequency and fungal counts were employed in studying the seasonal fluctuations of each species or groups which showed a frequency of 50 percent or greater in one sampling date. Seasonal fluctuation could not be demonstrated for dominant species such as Mucor ramannianus, Trichoderma viride, Penicillium spp., Cephalosporium sp. W1 and Bisporomyces sp., while some species which were lower in frequency and fungal counts fluctuated between different sampling dates. In general agreement with what has been reported by many other investigators who have exmined the seasonal fluctuations of microorganisms in the soil, those species or groups which showed seasonal fluctuations decreased in Summer months. However, the factors which influenced on the seasonal fluctuations of micro-fungi seemed to be different. The fluctuations of the groups belonging to type 1 of the vertical distribution patterns of soil fungi correlated well with the addition of new fallen leaves and when organic matter was added to the forest floor in Summer, these groups markedly increased.