Mycorrhizal parameters of Larix sibirica fine roots across gradients of main environmental factors and altitude

Siberian larch (Larix sibirica) forests cover the largest areas in the Eurasian boreal zone, but the knowledge on its root system and ectomycorrhizas (EMs) are insufficient. The aim of this research is to find out whether the morphological parameters of L. sibirica EMs respond to the changes in altitude and main environmental factors. We measured the EM diameter, root diameter, mantle width and volume share, share of tannin cell layers, EM density and length of L. sibirica fine roots in four main types of habitats across the altitudinal gradient in the Urals. The diversity of fungal mantle types depended on the type of habitat. The minimal diversity of fungal mantles and the prevalence of plectenchymatous mantles were found in moister and unfertile habitats of sphagnous type. In other types of habitats, the diversity of fungal mantle types was approximately twice higher. A combination of factors (habitat type and altitude) significantly determined all quantitative parameters of the Larix EMs under study. We found a reduction in the EM linear dimensions with increasing altitude and a deterioration of environmental conditions, accompanied by a decrease in their functional parameters with a slight increase in the EM density and the share of nonmycorrhizal roots.