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Article Dans Une Revue Journal of Experimental Botany Année : 2010

The effects of sap ionic composition on xylem vulnerability to cavitation

Résumé

Recent evidence of ion-mediated changes in pit membrane porosity suggests that plants may modulate the hydraulic conductance of their xylem conduits. Under the current paradigm, membrane porosity also determines conduit vulnerability to water stress-induced cavitation. Therefore, the hypothesis of an ion-mediated regulation of xylem vulnerability to cavitation in trees was tested. Segments of five Angiosperm and two Gymnosperm species were infiltrated with ultra-pure deionized water as a reference fluid or with a 50 mM KCl solution. KCl had a strong impact on segment conductance with either a positive or a negative effect across species. When 1 mM CaCl(2) was added to the reference solution, the effect of KCl was minimized for most species. By contrast, segment vulnerability to cavitation was only slightly influenced by the presence of KCl in the solution. From this it was concluded that the mechanisms controlling pit membrane permeability to water flow and its resistance to the penetration of air bubbles are largely uncoupled, which suggests that the hypothesis of a porous structure of pit membranes should be revisited.

Domaines

Botanique

Dates et versions

hal-01189438 , version 1 (01-09-2015)

Identifiants

Citer

Hervé Cochard, Stéphane Herbette, Encarni Hernandez, Teemu Höltta, Maurizio Mencuccini. The effects of sap ionic composition on xylem vulnerability to cavitation. Journal of Experimental Botany, 2010, 61 (1), pp.275-285. ⟨10.1093/jxb/erp298⟩. ⟨hal-01189438⟩
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