University Of Tasmania

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Herb and conifer roots show similar high sensitivity to water deficit

journal contribution
posted on 2023-05-21, 02:37 authored by Ibrahim BourbiaIbrahim Bourbia, Pritzkow, C, Timothy BrodribbTimothy Brodribb

Root systems play a major role in supplying the canopy with water, enabling photosynthesis and growth. Yet, much of the dynamic response of root hydraulics and its influence on gas exchange during soil drying and recovery remains uncertain. We examined the decline and recovery of the whole root hydraulic conductance (Kr) and canopy diffusive conductance (gc) during exposure to moderate water stress in two species with contrasting root systems: Tanacetum cinerariifolium (herbaceous Asteraceae) and Callitris rhomboidea (woody conifer). Optical dendrometers were used to record stem water potential at high temporal resolution and enabled non-invasive measurements of Kr calculated from the rapid relaxation kinetics of water potential in hydrating roots. We observed parallel declines in Kr and gc to <20% of unstressed levels during the early stages of water stress in both species. The recovery of Kr after rewatering differed between species. T. cinerariifolium recovered quickly, with 60% of Kr recovered within 2 h, while C. rhomboidea was much slower to return to its original Kr. Recovery of gc followed a similar trend to Kr in both species, with C. rhomboidea slower to recover. Our findings suggest that the pronounced sensitivity of Kr to drought is a common feature among different plant species, but recovery may vary depending on root type and water stress severity. Kr dynamics are proposed to modulate gc response during and following drought.


Australian Research Council


Publication title

Plant Physiology










School of Natural Sciences


United States

Place of publication

American Society of Plant Biologists

Rights statement

Copyright 2021 American Society of Plant Biologists

Repository Status

  • Restricted

Socio-economic Objectives

Effects of climate change on Australia (excl. social impacts); Management of water consumption by plant production; Plant extract crops