Root grafts matter for inter-tree water exchange – a quantification of water translocation between root grafted mangrove trees using field data and model-based indications

Research output: Contribution to journalResearch articleContributedpeer-review


Background and Aims
Trees interconnected through functional root grafts can exchange resources, but the effect of exchange on trees remains under debate. A mechanistic understanding of resource exchange via functional root grafts will help understand their ecological implications for tree water exchange for individual trees, groups of trees and forest stands.

To identify the main patterns qualitatively describing the movement of sap between grafted trees, we reviewed the available literature on root grafting in woody plants that focus on tree allometry and resource translocation via root grafts. We then extended the BETTINA model, which simulates mangrove (Avicennia germinans) tree growth on the individual tree scale, to synthesize the available empirical information. Using allometric data from a field study in mangrove stands, we simulated potential water exchange and analysed movement patterns between grafted trees.

Key Results
In the simulations, relative water exchange ranged between −9.17 and 20.3 %, and was driven by gradients of water potential, i.e. differences in tree size and water availability. Moreover, the exchange of water through root grafts alters the water balance of trees and their feedback with the soil: grafted trees that receive water from their neighbours reduce their water uptake.

Our individual-tree modelling study is a first theoretical attempt to quantify root graft-mediated water exchange between trees. Our findings indicate that functional root grafts represent a vector of hydraulic redistribution, helping to maintain the water balance of grafted trees. This non-invasive approach can serve as a basis for designing empirical studies to better understand the role of grafted root interaction networks on a broader scale.


Original languageEnglish
Pages (from-to)317-330
Number of pages14
JournalAnnals of Botany
Issue number3
Publication statusPublished - 10 Jun 2022

External IDs

WOS 000822069000001
Mendeley db465c62-b18e-3681-8923-5336117f8af2
unpaywall 10.1093/aob/mcac074
Scopus 85138746060
ORCID /0000-0002-4542-6764/work/142246410
ORCID /0000-0001-6920-136X/work/142247178
ORCID /0000-0003-0473-2973/work/158305362



  • AVICENNIA-GERMINANS, Agent-based model, Avicennia germinans, BETTINA model, CERATOCYSTIS-FAGACEARUM, CONNECTIONS, HYDRAULIC REDISTRIBUTION, La Mancha Lagoon, PINE, RESPONSES, RHIZOPHORA-MANGLE, SALINITY, SOIL-WATER, TRANSPORT, conceptual model, mangroves, natural root grafting, tree-tree interaction, water exchange

Library keywords