title: The Péclet effect on leaf water enrichment correlates with leaf hydraulic conductance and mesophyll conductance for CO(2).
abstract: Leaf water gets isotopically enriched through transpiration, and diffusion of enriched water through the leaf depends on transpiration flow and the effective path length (L). The aim of this work was to relate L with physiological variables likely to respond to similar processes. We studied the response to drought and vein severing of leaf lamina hydraulic conductance (K(lamina) ), mesophyll conductance for CO(2) (g(m) ) and leaf water isotope enrichment in Vitis vinifera L cv. Grenache. We hypothesized that restrictions in water pathways would reduce K(lamina) and increase L. As a secondary hypothesis, we proposed that, given the common pathways for water and CO(2) involved, a similar response should be found in g(m) . Our results showed that L was strongly related to mesophyll variables, such as K(lamina) or g(m) across experimental drought and vein-cutting treatments, showing stronger relationships than with variables included as input parameters for the models, such as transpiration. Our findings were further supported by a literature survey showing a close link between L and leaf hydraulic conductance (K(leaf) = 31.5 × L(-0.43) , r(2) = 0.60, n = 24). The strong correlation found between L, K(lamina) and g(m) supports the idea that water and CO(2) share an important part of their diffusion pathways through the mesophyll.
authors: Department of Crop and Forest Science, Universitat de Lleida, Lleida, Spain.
authors: Juan Pedro
authors: JP
authors: Ferrio
authors: Alícia
authors: A
authors: Pou
authors: Igor
authors: I
authors: Florez-Sarasa
authors: Arthur
authors: A
authors: Gessler
authors: Naomi
authors: N
authors: Kodama
authors: Jaume
authors: J
authors: Flexas
authors: Miquel
authors: M
authors: Ribas-Carbó
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D055864:Droughts; D008954:Models, Biological; D018515:Plant Leaves / Q000502:physiology*; D018526:Plant Transpiration; D027843:Vitis / Q000502:physiology; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water; D002245:Carbon Dioxide