Ectomycorrhizal syntheses with Picea abies and three fungal species: a case study on the use of an in vitro technique to identify naturally occurring ectomycorrhizae

摘要

Ectomycorrhizal syntheses betweenPicea abiesand the fungal associatesScleroderma citrinum,Boletus luridus, andTricholoma vaccinumwere carried out using Melin's Erlenmeyer flask technique. The symbioses ofS. citrinumwere characterized by a mantle composed of an outer prosenchymatous and an inner synenchymatous layer. The mantles ofB. luridusandT. vaccinumwere solely prosenchymatous. Rhizomorphs were produced in all treatments, but only in association withS. citrinumwere they differentiated with additional, enlarged hyphae. All synthesized ectomycorrhizae were white or whitish to light orange and greyishorange. On large-scale root sampling in two differingPicea abiesforests in Switzerland, nine out of a total of 22 morphological types of ectomycorrhizae were white or yellow in colour and were, therefore, comparable with the synthesized ectomycorrhizae. These nine natural types generally had distinct mantle features (irregular synenchyma, gelatinous matrix, cystides, thick-walled hyphae), but mostly lacked clamp connections. Synthesized ectomycorrhizae, on the other hand, lacked distinct mantle characteristics and always had clamp connections. Natural and synthesized white or yellow ectomycorrhizae did not coincide morphologically and thus identification of the fungal partners of natural symbioses by means ofin vitro-synthesis with potential ectomycorrhizal fungi was not possible in the present study.