Efficacy of ectomycorrhizal basidiomycetes on Japanese larch seedlings assessed by ergosterol assay

Five fungal species, Suillus grevillei, Boletinus cavipes, Inocybe kobayasii, Lactarius porninsis and Gomphidius maculatus were examined for ergosterol content during mycorrhizal formation. Ergosterol assay was a suitable method for monitoring establishment of 5 ectomycorrhizal fungi on roots. Ergosterol contents were positively correlated to biomass of each of 5 ectomycorrhizal basidiomycetes growing on Melin-Norkrans medium, ranging 1.78-2.36 μg mg^-1 dry mycelia. These fungi formed ectomycorrhizae with Japanese larch seedlings in container-grown axenic culture. There were significant correlations between overall mycorrhizal density and seedling growth such as root length and shoot height at 6 mo. Mycorrhizal seedlings accumulated more mass in the root system and mycorrhizae compared with nonmycorrhizal seedlings.