Abstract

Purpose Mycorrhizal fungi are critical for the growth and survival of trees although the knowledge on the extent of their association with different tree species in the boreal forest remains limited.Methods We examined the vertical distribution and composition of the root mycorrhizal communities of black spruce (Picea mariana (Mill.) B.S.P) and trembling aspen (Populus tremuloides Michx) along three soil layers (organic, minerals top 0-15 cm and bottom 15-30 cm) in pure and mixed stands, using next generation sequencing.Results We found that spruce and aspen differ in the composition of their mycorrhizal communities in respective pure stands. The difference was present also in mixed stands, despite a shift in the composition of species-specific mycorrhizal communities between pure and mixed stands. In mixed stands, the relative abundance of spruce-specialist mycorrhizae in the organic layer was higher than that of aspenspecialists. The opposite pattern was observed in the mineral soil. The mixed stands exhibited lower richness and abundance of generalist mycorrhizae in the organic and in the mineral soil layers.Conclusion The results suggest that it is the soil chemistry that structure species-specific mycorrhizal communities between pure stands and along different soil depth within stands. However, in mixed stands, it is the identity of tree species that determines the structure of mycorrhizae communities within soil layers. We speculate that the differences in the richness and abundance of individual mycorrhizal communities of spruce and aspen along the soil profile would likely contribute to stronger partitioning of tree nutrient uptake between these two species in mixed stands.

Keywords

Boreal forest; Mycorrhizal fungi; Stand composition; Nutrient partitioning; Soil nutrition

Published in

Plant and Soil
2022, volume: 479, number: 1, pages: 85-105
Publisher: SPRINGER

Authors' information