Research article - Peer-reviewed, 2022
Water taken up through the bark is detected in the transpiration stream in intact upper-canopy branchesGimeno, Teresa E.; Stangl, Zsofia R.; Barbeta, Adria; Saavedra, Noelia; Wingate, Lisa; Devert, Nicolas; Marshall, John D.
AbstractAlternative 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 H-2-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 (delta H-2 and delta O-18) of water vapour, before sampling for analyses of delta H-2 and delta O-18 in tissue waters. Xylem, bark and leaf waters from segments downstream from the bandages were H-2-enriched whereas delta O-18 was similar to controls. Transpiration was positively correlated with H-2-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.
Keywordsbark; deuterium; drought; European beech; frost; hydrogen; oxygen; Scots pine; water stable isotopes; xylem
Published inPlant, Cell and Environment
2022, volume: 45, number: 11, pages: 3219-3232
Gimeno, Teresa E.
Basque Centre for Climate Change (BC3)
Stangl , Zsofia Reka (Stangl, Zsofia Réka)
University of Barcelona
Marshall, John D (Marshall, John)
UKÄ Subject classification
URI (permanent link to this page)