Definition of Siberian spruce ectomycorrhizal morphotypes and vitality by fluorescence and rDNA sequence analysis

Ectomycorrhizae play a key role in functioning of the forest ecosystems where they are the major consumers of carbon. Picea obovata is the main forest form- ing species in the European Northeast of Russia, forming ectomycorrhizae with high diversity of fungi species. Our pioneer study to identify Picea obovata ec- tomycorrhizae morphotypes was based on examining ectomycorrhizal roots and further subjecting them to DNA extraction, amplification and sequencing of ITS region of rDNA. Ectomycorrhizal root tips of Siberian spruce were sampled in bilberry-sphagnum spruce forest of European Russia (Komi Republic) during one growing season. We estimated ten mycorrhizal morphotypes, four species of ec- tomycorrhizal fungi were identified. One of the methods of studying the physio- logical activity of ectomycorrhizae is to determine the fluorescence intensity of live cells by fluorescein diacetat (FDA). Fluorescence activity of ectomycorrhizal covers depends on physiological condition of trees and species composition of fungi forming mycorrhiza. To access the activity we used ten ectomycorrhizal types of Picea obovata after staining the tissues of the ectomycorrhizae with FDA. Using fluorescence microscopy we revealed differences between ectomy- corrhizal types in the FDA-hydrolizing activity of various tissue layers of my- corrhizas: cortex, fungal cover, Hartig net and stele. Cortex and stele of all my- corrhizal morphotypes were mainly characterized by bright coloration indicating the successful functioning of fine spruce roots in the plant community. Identi- fied by DNA-identification fungal symbionts Tomentella bryophila, Tomentella sublilacina, Cortinarius hemitrichus formed ectomycorrhizae with an average fluorescent activity. All main tissues of coniferous in ectomycorrhazas of Ceno- coccum geophillum were characterized by higher fluorescence activity. Ectomy- corrhizal morphotypes with fungal covers H and C were also highly active. The thickness of fungal covers of highly active ectomycorrhizae was maximal.