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Titre du document / Document title

Convergent tapering of xylem conduits in different woody species. Commentary

Auteur(s) / Author(s)

ANFODILLO Tommaso (1) ; CARRARO Vinicio (1) ; CARRER Marco (1) ; FIOR Claudio (1) ; ROSSI Sergio (1) ; NIKLAS K. J. (Commentateur (texte écrit)) (2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) University of Padova, Department TeSAF, Treeline Ecology Research Unit, Viale dell'Università, 16, 35020 Legnaro (PD), ITALIE
(2) Department of Plant Biology, Cornell University, Ithaca, NY 14853, ETATS-UNIS

Résumé / Abstract

• A recent theoretical model (the West, Brown and Enquist, WBE model) hypothesized that plants have evolved a network of xylem conduits with a tapered structure (narrower conduits distally) which should minimize the cost of water transport from roots to leaves. Specific measurements are required to test the model predictions. • We sampled both angiosperms and gymnosperms (50 trees) growing in different environments with heights ranging from 0.5 to 44.4 m, measuring variations of the xylem-conduit diameter from tree top to stem base. • In all trees measured, mean hydraulically weighted conduit diameters (Dh) at the tree top were narrower than those at the stem base. In actively growing trees, the longitudinal variation of Dh showed a degree of tapering in agreement with WBE predictions, while trees close to their maximum height showed slightly lower conduit tapering. Comparing different species, a very good correlation was observed between degree of xylem tapering and tree height (r2 = 0.88; P < 0.0001) independently of any other variable (age, site, altitude, etc.). • As predicted by WBE, sampled trees seemed to converge towards similar xylem conduit tapering. However, trees approaching their maximum height had a nonoptimal tapering which appeared insufficient to compensate for the progressive increase in tree height.

Revue / Journal Title

New phytologist    ISSN  0028-646X   CODEN NEPHAV 

Source / Source

2006, vol. 169, no2, [Note(s): 219-221, 279-290 [15 p.]] (1 p.1/4)

Langue / Language

Anglais

Editeur / Publisher

Blackwell, Oxford, ROYAUME-UNI  (1902) (Revue)

Mots-clés anglais / English Keywords

Softwood forest tree

;

Hardwood forest tree

;

Spermatophyta

;

Gymnospermae

;

Angiospermae

;

Hydraulic conductivity

;

Constraint

;

Anatomy

;

Theoretical model

;

Translocation

;

Water

;

Xylem

;

Mots-clés français / French Keywords

Arbre forestier résineux

;

Arbre forestier feuillu

;

Spermatophyta

;

Gymnospermae

;

Angiospermae

;

Conductivité hydraulique

;

Contrainte

;

Anatomie

;

Modèle théorique

;

Translocation

;

Eau

;

Xylème

;

Mots-clés espagnols / Spanish Keywords

Arbol forestal resinoso

;

Arbol forestal frondoso

;

Spermatophyta

;

Gymnospermae

;

Angiospermae

;

Conductividad hidráulica

;

Coacción

;

Anatomía

;

Modelo teórico

;

Translocación

;

Agua

;

Xilema

;

Mots-clés d'auteur / Author Keywords

anatomy

;

evolution

;

hydraulic constraints

;

tapering

;

tree height

;

xylem conduits

;

Localisation / Location

INIST-CNRS, Cote INIST : 3019, 35400013463816.0060

Nº notice refdoc (ud4) : 17507232



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