Re‐examining the evidence for the mother tree hypothesis – resource sharing among trees via ectomycorrhizal networks

Autor: Nils Henriksson, John Marshall, Mona N. Högberg, Peter Högberg, Andrea Polle, Oskar Franklin, Torgny Näsholm
Rok vydání: 2023
Předmět:
Zdroj: New Phytologist.
ISSN: 1469-8137
0028-646X
DOI: 10.1111/nph.18935
Popis: Seminal scientific papers positing that mycorrhizal fungal networks can distribute carbon (C) among plants have stimulated a popular narrative that overstory trees, or 'mother trees', support the growth of seedlings in this way. This narrative has far-reaching implications for our understanding of forest ecology and has been controversial in the scientific community. We review the current understanding of ectomycorrhizal C metabolism and observations on forest regeneration that make the mother tree narrative debatable. We then re-examine data and conclusions from publications that underlie the mother tree hypothesis. Isotopic labeling methods are uniquely suited for studying element fluxes through ecosystems, but the complexity of mycorrhizal symbiosis, low detection limits, and small carbon discrimination in biological processes can cause researchers to make important inferences based on miniscule shifts in isotopic abundance, which can be misleading. We conclude that evidence of a significant net C transfer via common mycorrhizal networks that benefits the recipients is still lacking. Furthermore, a role for fungi as a C pipeline between trees is difficult to reconcile with any adaptive advantages for the fungi. Finally, the hypothesis is neither supported by boreal forest regeneration patterns nor consistent with the understanding of physiological mechanisms controlling mycorrhizal symbiosis.
Databáze: OpenAIRE
Externí odkaz: