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

The potential of natural root grafts in mitigating temporal and spatial resource limitations is unrecognized. Uncovering the mechanisms of inter-tree water transfer through grafted roots can provide a new perspective on tree-tree interaction in regard to competition and cooperation, and on a plant’s ability to cope with water stress. Using non-invasive modelling techniques and allometric tree data of black mangroves (Acivennia germinans), Wimmler and colleagues calculated the potential water exchange between trees. They found that water transfer through root grafts is a yet unrecognized vector of hydraulic redistribution, which influences the water balance of trees. In the model, water uptake and exchange is driven by water potential gradients, which are caused, inter alia, by tree size or porewater salinity. The model reproduced water exchange patterns observed in nature and thus provides a first attempt to quantify water movement between trees.

The study by Marie-Christin Wimmler, Alejandra G Vovides, Ronny Peters, Marc Walther, Nadezhda Nadezhdina and Uta Berger was published in Annals of Botany and can be viewed here: https://doi.org/10.1093/aob/mcac074