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  • Stomatal closure as a driver of minimum leaf conductance declines at high temperature and vapor pressure deficit in Quercus

This content will become publicly available on December 23, 2025

Title: Stomatal closure as a driver of minimum leaf conductance declines at high temperature and vapor pressure deficit in Quercus
Abstract Rising global temperatures and vapor pressure deficits (VPDs) are increasing plant water demand and becoming major drivers of large-scale plant mortality. Controlling transient leaf water loss after stomatal closure (minimum stomatal conductance [gmin]) is recognized as a key trait determining how long plants survive during soil drought. Yet, substantial uncertainty remains regarding how gmin responds to elevated temperatures and VPD and the underlying mechanisms. We measured gmin in 24 Quercus species from temperate and Mediterranean climates to determine whether gmin was sensitive to a coupled temperature and VPD increase. We also explored mechanistic links to phenology, climate, evolutionary history, and leaf anatomy. We found that gmin in all species exhibited a nonlinear negative temperature and VPD dependence. At 25 °C (VPD = 2.2 kPa), gmin varied from 1.19 to 8.09 mmol m−2 s−1 across species but converged to 0.57 ± 0.06 mmol m−2 s−1 at 45 °C (VPD = 6.6 kPa). In a subset of species, the effect of temperature and VPD on gmin was reversible and linked to the degree of stomatal closure, which was greater at 45 °C than at 25 °C. Our results show that gmin is dependent on temperature and VPD, is highly conserved in Quercus species, and is linked to leaf anatomy and stomatal behavior.  more » « less
Award ID(s):
1943583 1950498
PAR ID:
10595478
Author(s) / Creator(s):
; ;
Publisher / Repository:
Plant Physiology
Date Published:
Journal Name:
Plant Physiology
Volume:
197
Issue:
1
ISSN:
0032-0889
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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