LARTER, Maximilian; PFAUTSCH, Sebastian; DOMEC, Jean-Christophe; TRUEBA, Santiago; NAGALINGUM, Nathalie; DELZON, Sylvain

doi:10.1111/nph.14545

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LARTER, Maximilian
Biodiversité, Gènes & Communautés [BioGeCo]

PFAUTSCH, Sebastian
Hawkesbury Institute for the Environment [Richmond] [HIE]

DOMEC, Jean-Christophe
Interactions Sol Plante Atmosphère [UMR ISPA]
Nicholas School of the Environment

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Ce document a été publié dans

New Phytologist. 2017, vol. 215, n° 1, p. 97-112

Wiley

Résumé en anglais

Xylem vulnerability to embolism is emerging as a major factor in drought-induced tree mortality events across the globe. However, we lack understanding of how and to what extent climate has shaped vascular properties or functions. We investigated the evolution of xylem hydraulic function and diversification patterns in Australia's most successful gymnosperm clade, Callitris, the world's most drought-resistant conifers. For all 23 species in this group, we measured embolism resistance (P50 ), xylem specific hydraulic conductivity (Ks ), wood density, and tracheary element size from natural populations. We investigated whether hydraulic traits variation linked with climate and the diversification of this clade using a time-calibrated phylogeny. Embolism resistance varied widely across the Callitris clade (P50 : -3.8 to -18.8 MPa), and was significantly related to water scarcity, as was tracheid diameter. We found no evidence of a safety-efficiency tradeoff; Ks and wood density were not related to rainfall. Callitris diversification coincides with the onset of aridity in Australia since the early Oligocene. Our results highlight the evolutionary lability of xylem traits with climate, and the leading role of aridity in the diversification of conifers. The uncoupling of safety from other xylem functions allowed Callitris to evolve extreme embolism resistance and diversify into xeric environments.< Réduire

Mots clés

transfert hydraulique

xylème

changement climatique

australie

embolie

Mots clés en anglais

drought

climate change

diversification

ecophysiology

embolism resistance

evolution

gymnosperms

xylem

global change

embolism

DOI

http://dx.doi.org/10.1111/nph.14545

Project ANR

Plateforme d'Innovation " Forêt-Bois-Fibre-Biomasse du Futur " - ANR-10-EQPX-0016

Origine

Importé de hal

Unités de recherche

BioGeCo (Biodiversité Gènes & Communautés) - UMR 1202