An assessment of below-ground ectomycorrhizal diversity of Abies alba Miller in central Italy

In the framework of an ongoing study on the mycorrhizal associations of silver fir (Abies alba Mill., we investigated the below-ground diversity of ectomycorrhizal communities in ten field sites located in five distinct natural A. alba woods, situated in the central part of the Apennine chain (Abruzzo region, Italy). Based on macro- and microscopic features, a total of 48 morphologically distinct ectomycorrhizal types have been classified on mature trees of A. alba, 37 of which are reported here for the first time. Ectomycorrhizal morphotypes were partially characterized, and their main features described; in many cases, the relevant fungal symbiont was identified at the level of species or genus. The number of distinguishable morphotypes per site was, with few exceptions, rather homogeneous, ranging from (5) 8 to 13 (20). Comparison of morphotype occurrence revealed that only few types were encountered in five or more sampled sites, whereas the vast majority of types was less frequent. The present study revealed a considerably high species diversity of the ectomycorrhizal symbionts of A. alba in a quite restricted area, thus raising interesting questions as to the ectomycorrhizal potential of this host tree over its entire, large natural range.