Water loss after stomatal closure : quantifying leaf minimum conductance and minimal water use in nine temperate European tree species during a severe drought

© The Author(s) 2024. Published by Oxford University Press..

Residual canopy transpiration (Emin_canop) is a key physiological trait that determines trees' survival time under drought after stomatal closure and after trees have limited access to soil water. Emin_canop mainly depends on leaf minimum conductance (gmin) and vapor pressure deficit. Here we determined the seasonal variation of gmin and how gmin is related to interspecies variation in leaf cuticular and stomatal traits for nine European tree species in a mature forest. In addition, we determined the species-specific temperature responses of gmin. With this newly obtained insight, we calculated Emin_canop for the nine species for one day at our research site during the 2022 central European hot drought. Our results show that at ambient temperatures gmin ranged from 0.8 to 4.8 mmol m-2 s-1 across the nine species and was stable in most species throughout the growing season. The interspecies variation of gmin was associated with leaf cuticular and stomatal traits. Additionally, gmin exhibited strong temperature responses and increased, depending on species, by a factor of two to four in the range of 25-50 °C. For the studied species at the site, during a single hot drought day, Emin_canop standardized by tree size (stem basal area) ranged from 2.0 to 36.7 L m-2, and non-standardized Emin_canop for adult trees ranged from 0.3 to 5.3 L. Emin_canop also exhibited species-specific rapid increases under hotter temperatures. Our results suggest that trees, depending on species, need reasonable amounts of water during a drought, even when stomates are fully closed. Species differences in gmin and ultimately Emin_canop can, together with other traits, affect the ability of a tree to keep its tissue hydrated during a drought and is likely to contribute to species-specific differences in drought vulnerability.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:44

Enthalten in:

Tree physiology - 44(2024), 4 vom: 03. Apr.

Sprache:

Englisch

Beteiligte Personen:

Wang, Songwei [VerfasserIn]
Hoch, Günter [VerfasserIn]
Grun, Georges [VerfasserIn]
Kahmen, Ansgar [VerfasserIn]

Links:

Volltext

Themen:

059QF0KO0R
Canopy desiccation
Drought tolerance
Functional traits
Hot temperature
Journal Article
Minimum transpiration
Water

Anmerkungen:

Date Completed 05.04.2024

Date Revised 06.04.2024

published: Print

Citation Status MEDLINE

doi:

10.1093/treephys/tpae027

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369020693