University Of Tasmania

File(s) under permanent embargo

Drought response strategies define the relative contributions of hydraulic dysfunction and carbohydrate depletion during tree mortality

journal contribution
posted on 2023-05-19, 08:54 authored by Mitchell, PJ, Anthony O'GradyAnthony O'Grady, Tissue, DT, White, DA, Maria Ottenschlaeger, Pinkard, EA
  • Plant survival during drought requires adequate hydration in living tissues and carbohydrate reserves for maintenance and recovery. We hypothesized that tree growth and hydraulic strategy determines the intensity and duration of the ‘physiological drought’, thereby affecting the relative contributions of loss of hydraulic function and carbohydrate depletion during mortality.
  • We compared patterns in growth rate, water relations, gas exchange and carbohydrate dynamics in three tree species subjected to prolonged drought.
  • Two Eucalyptus species (E. globulus, E. smithii) exhibited high growth rates and water-use resulting in rapid declines in water status and hydraulic conductance. In contrast, conservative growth and water relations in Pinus radiata resulted in longer periods of negative carbon balance and significant depletion of stored carbohydrates in all organs. The ongoing demand for carbohydrates from sustained respiration highlighted the role that duration of drought plays in facilitating carbohydrate consumption.
  • Two drought strategies were revealed, differentiated by plant regulation of water status: plants maximized gas exchange, but were exposed to low water potentials and rapid hydraulic dysfunction; and tight regulation of gas exchange at the cost of carbohydrate depletion. These findings provide evidence for a relationship between hydraulic regulation of water status and carbohydrate depletion during terminal drought.
  • History

    Publication title

    New Phytologist








    School of Natural Sciences


    Blackwell Publishing Ltd

    Place of publication

    9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

    Rights statement

    Copyright 2012 CSIRO

    Repository Status

    • Restricted

    Socio-economic Objectives

    Expanding knowledge in the biological sciences