December 03, 2020

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High-Resolution Minirhizotrons Reveal Root-Fungal Dynamics in an Experimentally Warmed Peatland

Peer into the belowground world of a boreal peatland through non-destructive, high-resolution minirhizotron technology.

Minirhizotron images from the SPRUCE experiment of (a) a tree fine root, (b) a shrub root, (c) a sedge root, (d) a dark ectomycorrhiza, (e) a light ectomycorrhiza, (f) dark fungal hyphae, (g) light fungal hyphae, (h) fungal rhizomorphs, and (i) a fungal sporocarp.
[Image Credit: Image courtesy of Camille Defrenne. The image is licensed under CC BY 4.0 and is published in the following article: Defrenne, C. E., J. Childs, C. W. Fernandez, and M. Taggart, et al, “High-resolution minirhizotrons advance our understanding of root-fungal dynamics in an experimentally warmed peatland.” Plants, People, Planet. 00:1–13 (2020). [https://doi.org/10.1002/ppp3.10172].]

The Science

Researchers at the Spruce and Peatland Responses Under Changing Environments (SPRUCE) whole-ecosystem warming experiment pioneered the use of high-resolution minirhizotrons in a forested peat bog to explore temporal variation in the abundance and growth of plant fine roots and their fungal partners under variable temperature and moisture conditions. The research team demonstrated that the abundance and growth of shrub roots and light-colored, thick fungal vegetative parts will increase and the belowground active season will be extended under warmer peat temperatures. These changes may reduce peat carbon accumulation on the boreal landscape.

The Impact

Team members now have a capability to study fungi beneath peatlands and other ecosystems. As rising temperatures rapidly modify the boreal biome, an understanding of peatland belowground biodiversity is crucial to predict the role of peatlands in carbon cycles and climate change.

Summary

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 the team 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.

Principal Investigator

Colleen Iversen
Oak Ridge National Laboratory
iversencm@ornl.gov

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
daniel.stover@science.doe.gov

Funding

The Spruce and Peatland Responses Under Changing Environments experiment is supported by the Office of Biological and Environmental Research within the U.S. Department of Energy’s Office of Science. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. A portion of this work was performed by the Universities of Minnesota and California-Riverside.

Related Links

References

C. E. Defrenne, J. Childs, C. W. Fernandez, and M. Taggart, et al. "High-resolution minirhizotrons advance our understanding of root-fungal dynamics in an experimentally warmed peatland". Plants, People, Planet 1–13  (2020). https://doi.org/10.1002/ppp3.10172.

J. Childs, C. E. Defrenne, D. J. Brice, and J. Woodward, et al. SPRUCE High-Resolution Minirhizotrons in an Experimentally-Warmed Peatland Provide an Unprecedented Glimpse at Fine Roots and their Fungal Partners: Supporting Data. 2020. Oak Ridge National Laboratory, TES SFA, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.