Water taken up through the bark is detected in the transpiration stream in intact upper-canopy branches.

Autor: Gimeno TE; CREAF, 08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain.; Basque Centre for Climate Change (BC3), Leioa, Spain., Stangl ZR; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden., Barbeta A; BEECA, Universitat de Barcelona, Barcelona, Catalonia, Spain., Saavedra N; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden., Wingate L; INRAE, UMR1391 ISPA, Villenave d'Ornon, France., Devert N; INRAE, UMR1391 ISPA, Villenave d'Ornon, France., Marshall JD; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
Jazyk: angličtina
Zdroj: Plant, cell & environment [Plant Cell Environ] 2022 Nov; Vol. 45 (11), pp. 3219-3232. Date of Electronic Publication: 2022 Aug 18.
DOI: 10.1111/pce.14415
Abstrakt: Alternative water uptake pathways through leaves and bark complement water supply with interception, fog or dew. Bark water-uptake contributes to embolism-repair, as demonstrated in cut branches. We tested whether bark water-uptake could also contribute to supplement xylem-water for transpiration. We applied bandages injected with 2 H-enriched water on intact upper-canopy branches of Pinus sylvestris and Fagus sylvatica in a boreal and in a temperate forest, in summer and winter, and monitored transpiration and online isotopic composition (δ 2 H and δ 18 O) of water vapour, before sampling for analyses of δ 2 H and δ 18 O in tissue waters. Xylem, bark and leaf waters from segments downstream from the bandages were 2 H-enriched whereas δ 18 O was similar to controls. Transpiration was positively correlated with 2 H-enrichment. Isotopic compositions of transpiration and xylem water allowed us to calculate isotopic exchange through the bark via vapour exchange, which was negligible in comparison to estimated bark water-uptake, suggesting that water-uptake occurred via liquid phase. Results were consistent across species, forests and seasons, indicating that bark water-uptake may be more ubiquitous than previously considered. We suggest that water taken up through the bark could be incorporated into the transpiration stream, which could imply that sap-flow measurements underestimate transpiration when bark is wet.
(© 2022 John Wiley & Sons Ltd.)
Databáze: MEDLINE
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