Study

The magnitude and control of carbon transfer between plants linked by a common mycorrhizal network

Robinson, D.; Fitter, A.

Journal of Experimental Botany, 1999

Peer-reviewedmodelling studynot applicable

What they did

Published isotope-labelling results on carbon movement between linked plants were reanalysed, asking how much of the labelled carbon actually reached the tissues of the receiving plant rather than remaining in the fungus occupying its roots.

Studied in: Glomeromycota, Tracheophyta

What they found

Most of the transferred label was accounted for by carbon sitting in the fungal tissue inside the recipient root, not by carbon incorporated into the recipient plant. Net transfer into plant tissue, where it could be resolved at all, was very small relative to the recipient’s own budget.

What it means

The authors' reading, and ours. Where they differ, that difference is the point.

How the authors put it

Apparent plant-to-plant carbon transfer through mycorrhizal networks is largely carbon held in the fungus, and net transfer into recipient plants is unlikely to be ecologically significant in most circumstances.

How NatureHQ reads it

The measurement problem at the heart of the whole "trees feed each other" story, stated early and never really answered. A label detected in a recipient root can be inside the recipient or inside the fungus growing through it, and separating the two is genuinely hard. Everything downstream — mother trees, shared food, forest cooperation — depends on a distinction that the standard method struggles to make. That is not a reason to dismiss the phenomenon; it is the reason to state carefully what has been shown.

Limitations

A reanalysis of others’ data, constrained by what those studies reported.
Focused on arbuscular mycorrhizas; some ectomycorrhizal systems show larger fluxes.
Later work using methods that separate the compartments better exists and reaches a range of conclusions.