Title: High‐resolution minirhizotrons advance our understanding of root‐fungal dynamics in an experimentally warmed peatland

Abstract

Societal Impact Statement Mycorrhizal fungi enable plants to thrive in the cold, waterlogged, organic soils of boreal peatlands and, with saprotrophic fungi, largely contribute to the sequestration of atmospheric carbon in peat. Hence, fungi support the contribution of peatlands to global climate regulation, on which society depends. Here we used high‐resolution minirhizotrons for an unprecedented glimpse of the belowground world of a forested bog and highlighted linkages between environmental change and the abundance, dynamics, and morphology of vascular plant fine roots and fungal mycelium. These changes may have implications for peat carbon accumulation on the boreal landscape. Summary Minirhizotron technology has rarely been deployed in peatlands which has limited our understanding of root‐fungal dynamics in one of planet's most carbon‐dense ecosystems. We used novel, high‐resolution minirhizotrons in a forested bog to explore temporal variation in the abundance and growth of plant fine roots and fungal mycelium with changes in peat temperature and moisture. We utilized the framework of the Spruce and Peatland Responses Under Changing Environments experiment and focused on two minirhizotron tubes installed at the coldest (+0, elevated CO ₂ ) and warmest (+9°C, elevated CO ₂ ) ends of the experimental temperature gradient, respectively. We found that inmore » warmer and drier peat, ericaceous shrub roots and ectomycorrhizal fungal rhizomorphs were more abundant, and the growth of rhizomorphs and sporocarps was greater. In turn, fine roots of trees, ectomycorrhizas, and dark‐colored fungal hyphae were more abundant in colder, wetter peat. Ultimately, the belowground active season for both plant roots and fungi was extended by 62 days at the warmest compared to the coldest end of the gradient, with implications for belowground carbon, water, and nutrient fluxes. High‐resolution minirhizotrons in peatlands provided an unprecedented view of ericaceous shrub and tree fine roots and their mycorrhizal fungal partners in situ. Therefore, this technology advanced our understanding of linkages between environmental change and the abundance, morphology, and dynamics of vascular plant fine roots and fungal mycelium.« less

Authors:

Defrenne, Camille E.  ^[1];

• Search DOE PAGES for author "Defrenne, Camille E."
• Search DOE PAGES for ORCID "0000-0003-2767-4892"

Childs, Joanne ^[1]; Fernandez, Christopher W.  ^[2];

• Search DOE PAGES for author "Fernandez, Christopher W."
• Search DOE PAGES for ORCID "0000-0002-6310-6027"

Taggart, Michael  ^[3];

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• Search DOE PAGES for ORCID "0000-0001-6706-7195"

Nettles, W. Robert ^[1]; Allen, Michael F.  ^[3];

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• Search DOE PAGES for ORCID "0000-0001-5200-8758"

Hanson, Paul J.  ^[1];

• Search DOE PAGES for author "Hanson, Paul J."
• Search DOE PAGES for ORCID "0000-0001-7293-3561"

Iversen, Colleen M.  ^[1]

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• Search DOE PAGES for ORCID "0000-0001-8293-3450"

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+ Show Author Affiliations

1. Climate Change Science Institute and Environmental Sciences Division Oak Ridge National Laboratory Oak Ridge TN USA
2. Department of Plant and Microbial Biology University of Minnesota St. Paul MN USA
3. Department of Microbiology and Plant Pathology Center for Conservation Biology University of California‐Riverside Riverside CA USA

Publication Date:

Thu Dec 03 00:00:00 EST 2020

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1730983

Alternate Identifier(s):

OSTI ID: 1735437; OSTI ID: 1786620

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Published Article

Journal Name:

Plants, People, Planet

Additional Journal Information:

Journal Name: Plants, People, Planet; Journal ID: ISSN 2572-2611

Publisher:

New Phytologist Trust - Wiley

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; dynamics; fine roots; minirhizotron; mycorrhizal fungi; peatland; phenology; warming