University Of Tasmania

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Climate drives vein anatomy in Proteaceae

journal contribution
posted on 2023-05-17, 22:10 authored by Gregory JordanGregory Jordan, Timothy BrodribbTimothy Brodribb, Christopher BlackmanChristopher Blackman, Weston, PH

Premise of study: The mechanisms by which plants tolerate water deficit are only just becoming clear. One key factor in drought tolerance is the ability to maintain the capacity to conduct water through the leaves in conditions of water stress. Recent work has shown that a simple feature of the leaf xylem cells, the cube of the thickness of cell walls divided by the lumen width (t/b/)3), is strongly correlated with this ability.

Methods: Using ecologically, phylogenetically, and anatomically diverse members of Proteaceae, we tested the relationships between (t/b/)3) and climate, leaf mass per unit area, leaf area, and vein density. To test relationships at high phylogenetic levels (mostly genus), we used phylogenetic and nonphylogenetic single and multiple regressions based on data from 50 species. We also used 14 within-genus species pairs to test for relationships at lower phylogenetic levels.

Key results: All analyses revealed that climate, especially mean annual precipitation, was the best predictor of (t/b/)3). The variation in (t/b/)3) was driven by variation in both lumen diameter and wall thickness, implying active control of these dimensions. Total vein density was weakly related to (t/b/)3) but unrelated to either leaf area or climate.

Conclusions: We conclude that xylem reinforcement is a fundamental adaptation for water stress tolerance and, among evergreen woody plants, drives a strong association between rainfall and xylem anatomy. The strong association between (t/b/)3) and climate cannot be explained by autocorrelation with other aspects of leaf form and anatomy that vary along precipitation gradients.


Australian Research Council


Publication title

American Journal of Botany










School of Natural Sciences


Botanical Society of America, Inc.

Place of publication

Columbus, USA

Rights statement

Copyright 2013 Botanical Society of America

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the environmental sciences