The water relations of two tropical rainforest species (textlessemtextgreaterVirola surinamensistextless/emtextgreater and textlessemtextgreaterEperua falcatatextless/emtextgreater): Is textlessemtextgreaterVirolatextless/emtextgreater unusual as previously reported?
Résumé
textlessptextgreaterThe objective of this study was to examine the water relations and hydraulic architecture and vulnerability to cavitation in textlessemtextgreaterVirola surinamensis textless/emtextgreaterandtextlessemtextgreater V. micheliitextless/emtextgreater and to compare to similar measurements in textlessemtextgreaterEperua falcata. textless/emtextgreaterIn several previous reports textlessemtextgreaterVirolatextless/emtextgreater was seen to have a rather narrow range of xylem pressure potentials (textlessemtextgreaterΨtextless/emtextgreatertextlessemtextgreatertextlesssubtextgreaterxtextless/subtextgreatertextless/emtextgreater) near zero in the course of a wet-season day while having water fluxes quite close to textlessemtextgreaterEperuatextless/emtextgreater. We tested the hypothesis that the narrow range of textlessemtextgreaterΨtextless/emtextgreatertextlessemtextgreatertextlesssubtextgreaterxtextless/subtextgreatertextless/emtextgreater might be consistent with very high hydraulic conductivities of stems, roots and shoots and high vulnerability to cavitation in textlessemtextgreaterVirolatextless/emtextgreater compared to textlessemtextgreaterEperuatextless/emtextgreater. When this hypothesis proved false we concluded that the previous determinations of textlessemtextgreaterΨtextless/emtextgreatertextlessemtextgreatertextlesssubtextgreaterxtextless/subtextgreatertextless/emtextgreater might be wrong in textlessemtextgreaterVirolatextless/emtextgreater due to latex. We re-examined the determination of textlessemtextgreaterΨtextless/emtextgreatertextlessemtextgreatertextlesssubtextgreaterxtextless/subtextgreatertextless/emtextgreater in textlessemtextgreaterVirolatextless/emtextgreater by the pressure chamber technique and compared results to determination of textlessemtextgreaterΨtextless/emtextgreatertextlessemtextgreatertextlesssubtextgreaterleaftextless/subtextgreatertextless/emtextgreater by the thermocouple psychrometer technique and found that the likely range of textlessemtextgreaterΨtextless/emtextgreatertextlessemtextgreatertextlesssubtextgreaterxtextless/subtextgreatertextless/emtextgreater are more negative than previously reported. Problems concerning the determination of textlessemtextgreaterΨtextless/emtextgreatertextlessemtextgreatertextlesssubtextgreaterxtextless/subtextgreatertextless/emtextgreater in species with latex are discussed.textless/ptextgreater
Auteurs, date et publication :
Auteurs Têtè Sévérien Barigah , Gilbert Aussenac , Christopher Baraloto , Damien Bonal , Hervé Cochard , André Granier , Jean-Marc Guehl , Roland Huc , Mari A. Sobrado , Melvin T. Tyree
Publication : Journal of Plant Hydraulics
Date : 2014
Volume : 1
Pages : 002