University Of Tasmania
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The importance of xylem constraints in the distribution of conifer species

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journal contribution
posted on 2023-05-16, 11:53 authored by Timothy BrodribbTimothy Brodribb, Robert HillRobert Hill
Vulnerability of stem xylem to cavitation was measured in 10 species of conifers using high pressure air to induce xylem embolism. Mean values of air pressure required to induce a 50% loss in hydraulic conductivity (φ50) varied enormously between species, ranging from a maximum of 14.2 ± 0.6 MPa (corresponding to a xylem water potential of -14.2 MPa) in the semi-arid species Actinostrobus acuminatus to a minimum of 2.3 ± 0.2 MPa in the rainforest species Dacrycarpus dacrydioides. Mean φ50 was significantly correlated with the mean rainfall of the driest quarter within the distribution of each species. The value of φ50 was also compared with leaf drought tolerance data for these species in order to determine whether xylem dysfunction during drought dictated drought response at the leaf level. Previous data describing the maximum depletion of internal CO2 concentration (c(i)) in the leaves of these species during artificial drought was strongly correlated with φ50 suggesting a primary role of xylem in effecting leaf drought response. The possibility of a trade-off between xylem conductivity and xylem vulnerability was tested in a sub-sample of four species, but no evidence of an inverse relationship between φ50 and either stem-area specific (K(a)) or leaf-area specific conductivity (K1) was found.


Publication title

New Phytologist








School of Natural Sciences


Blackwell Publishing Ltd

Place of publication

Cambridge, UK

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the environmental sciences

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