BOUCHE, Pauline S.; DELZON, Sylvain; CHOAT, Brendan; BADEL, Eric; BRODRIBB, Timothy J.; BURLETT, Régis; COCHARD, Hervé; CHARRA-VASKOU, Katline; LAVIGNE, Bruno; LI, Shan; MAYR, Stefan; MORRIS, Hugh; TORRES RUIZ, Jose Manuel; ZUFFEREY, Vivian; JANSEN, Steven

doi:10.1111/pce.12680

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BOUCHE, Pauline S.
Biodiversité, Gènes & Communautés [BioGeCo]
Institute for Systematic Botany and Ecology

DELZON, Sylvain
Biodiversité, Gènes & Communautés [BioGeCo]

CHOAT, Brendan
Hawkesbury Institute for the Environment

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Article de revue

Ce document a été publié dans

Plant, Cell and Environment. 2016, vol. 39, n° 4, p. 860–870

Wiley

Résumé en anglais

Plants can be highly segmented organisms with an independently redundant design of organs. In the context of plant hydraulics, leaves may be less embolism resistant than stems, allowing hydraulic failure to be restricted to distal organs that can be readily replaced. We quantified drought-induced embolism in needles and stems of Pinus pinaster using high-resolution computed tomography (HRCT). HRCT observations of needles were compared with the rehydration kinetics method to estimate the contribution of extra-xylary pathways to declining hydraulic conductance. High-resolution computed tomography images indicated that the pressure inducing 50% of embolized tracheids was similar between needle and stem xylem (P50 needle xylem = −3.62 MPa, P50 stem xylem = −3.88 MPa). Tracheids in both organs showed no difference in torus overlap of bordered pits. However, estimations of the pressure inducing 50% loss of hydraulic conductance at the whole needle level by the rehydration kinetics method were significantly higher (P50 needle = −1.71 MPa) than P50 needle xylem derived from HRCT. The vulnerability segmentation hypothesis appears to be valid only when considering hydraulic failure at the entire needle level, including extra-xylary pathways. Our findings suggest that native embolism in needles is limited and highlight the importance of imaging techniques for vulnerability curves.< Réduire

Mots clés

hydraulic failures

Mots clés en anglais

conifer

embolised tracheids

wall deformation

direct visualization of water content

DOI

http://dx.doi.org/10.1111/pce.12680

Projet Européen

International Mobility Programme to Strengthen Skills and Excellence in Research for Agriculture

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Importé de hal

Unités de recherche

BioGeCo (Biodiversité Gènes & Communautés) - UMR 1202