Impacts of elevated CO2 levels and temperature on photosynthesis and stomatal closure along an altitudinal gradient are counteracted by the rising atmospheric vapor pressure deficit
Pernicová, Natálie (Mendel University in Brno)
Urban, Otmar (Czech Academy of Sciences)
Čáslavský, Josef (Czech Academy of Sciences)
Kolář, Tomáš (Mendel University in Brno)
Rybníček, Michal (Mendel University in Brno)
Sochová, Irena (Czech Academy of Sciences)
Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Bošeľa, Michal (Technical University in Zvolen)
Trnka, Miroslav (Mendel University in Brno)

Data:	2024
Resum:	The efficiency of water use in plants, a critical ecophysiological parameter closely related to water and carbon cycles, is essential for understanding the interactions between plants and their environment. This study investigates the effects of ongoing climate change and increasing atmospheric CO2 concentration on intrinsic (stomata-based; iWUE) and evaporative (transpiration-based; eWUE) water use efficiency in oak trees along a naturally small altitudinal gradient (130-630 m a. s. l. ) of Vihorlat Mountains (eastern Slovakia, Central Europe). To assess changes in iWUE and eWUE values over the past 60 years (1961-2020), stable carbon isotope ratios in latewood cellulose (δ13Ccell) of annually resolved tree rings were analyzed. Such an approach was sensitive enough to distinguish tree responses to growth environments at different altitudes. Our findings revealed a rising trend in iWUE, particularly in oak trees at low and middle altitudes. However, this increase was negligible at high altitudes. Warmer and drier conditions at lower altitudes likely led to significant stomatal closure and enhanced efficiency in photosynthetic CO2 uptake due to rising CO2 concentration. Conversely, the increasing intracellular-to-ambient CO2 ratio (Ci/Ca) at higher altitudes indicated lower efficiency in photosynthetic CO2 uptake. In contrast to iWUE, eWUE showed no increasing trends over the last 60 years. This suggests that the positive impacts of elevated CO2 concentrations and temperature on photosynthesis and stomatal closure are counteracted by the rising atmospheric vapor pressure deficit (VPD). These differences underscore the importance of the correct interpretation of stomata-based and transpiration-based WUEs and highlight the necessity of atmospheric VPD correction when applying tree-ring δ13C-derived WUE at ecosystem and global levels.
Ajuts:	Agencia Estatal de Investigación TED2021-132627B-I00 Agencia Estatal de Investigación PID2022-140808NB-I00
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Altitudinal gradient ; Climate change ; Chronologies ; Plant water use efficiency ; Quercus ; Spp ; Tree-ring carbon isotopes
Publicat a:	Science of the total environment, Vol. 921 (April 2024) , art. 171173, ISSN 1879-1026

DOI: 10.1016/j.scitotenv.2024.171173

10 p, 4.7 MB

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