Ectomycorrhizal fungi integrate nitrogen mobilisation and mineral weathering in boreal forest soil

Abstract

Tree growth in boreal forests is driven by ectomycorrhizal fungal mobilisation of organic nitrogen and mineral nutrients in soils with discrete organic and mineral horizons. However, there are no studies of how ectomycorrhizal mineral weathering and organic nitrogen mobilisation processes are integrated across the soil profile.We studied effects of organic matter (OM) availability on ectomycorrhizal functioning by altering the proportions of natural organic and mineral soil in reconstructed podzol profiles containing Pinus sylvestris plants, using (13)CO(2 )pulse labelling, patterns of naturally occurring stable isotopes (Mg-26 and N-15) and high-throughput DNA sequencing of fungal amplicons.Reduction in OM resulted in nitrogen limitation of plant growth and decreased allocation of photosynthetically derived carbon and mycelial growth in mineral horizons. Fractionation patterns of Mg-26 indicated that magnesium mobilisation and uptake occurred primarily in the deeper mineral horizon and was driven by carbon allocation to ectomycorrhizal mycelium. In this horizon, relative abundance of ectomycorrhizal fungi, carbon allocation and base cation mobilisation all increased with increased OM availability.Allocation of carbon through ectomycorrhizal fungi integrates organic nitrogen mobilisation and mineral weathering across soil horizons, improving the efficiency of plant nutrient acquisition. Our findings have fundamental implications for sustainable forest management and belowground carbon sequestration.

Keywords

boreal forests; carbon allocation; carbon sequestration; ectomycorrhizal fungi; mineral weathering; nitrogen mobilisation; organic matter; podzol horizons

Published in

New Phytologist
2024, Volume: 242, number: 4, pages: 1545-1560

SLU Authors

• Mahmood, Shahid

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Al-Azzawi, Zaenab

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• King, Katharine

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Köhler, Stephan

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Bishop, Kevin

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Finlay, Roger

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network


Sustainable Development Goals

SDG13 Climate action
SDG15 Life on land


UKÄ Subject classification

Ecology
Microbiology
Environmental Sciences


Publication identifier

DOI: https://doi.org/10.1111/nph.19260

Permanent link to this page (URI)

https://res.slu.se/id/publ/127514