Dynamics of fruit-body production and mycorrhiza formation of ectomycorrhizal ammonia fungi in warm temperate forests in Japan

To investigate the quantitative correlation between dynamics of ectomycorrhiza (ECM) formation and fruit-body production of the ammonia fungi, we treated forest soils in two ECM forests, a Castanopsis cuspidata forest and a Quercus serrata forest, in warm temperate Japan with urea to induce fruiting of ammonia fungi. We identified the ectomycorrhizae of two known species of ammonia fungi, Alnicola lactariolens and Hebeloma vinosophyllum, using morphological typing and PCR-RFLP. ECM initiation, increase, and subsequent decrease preceded the start, increase, and decrease of fruit-body production for each species. We also found many kinds of ECM fungi that did not develop fruit bodies after urea treatment during the observation period, which suggests that it is necessary to expand the definition of ammonia fungi from one that refers solely to the species reproducing on the ground to one which includes those in somatic forms in the soil.