Hydraulic acclimation in a Mediterranean oak subjected to permanent throughfall exclusion results in increased stem hydraulic capacitance.

Autor: Salomón RL; Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium., Steppe K; Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium., Ourcival JM; Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), CEFE UMR 5175, CNRS, Univ Montpellier, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier Cedex 5, France., Villers S; Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium., Rodríguez-Calcerrada J; Forest Genetics and Ecophysiology Research Group, Universidad Politécnica de Madrid, Madrid, Spain., Schapman R; Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium., Limousin JM; Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), CEFE UMR 5175, CNRS, Univ Montpellier, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier Cedex 5, France.
Jazyk: angličtina
Zdroj: Plant, cell & environment [Plant Cell Environ] 2020 Jun; Vol. 43 (6), pp. 1528-1544. Date of Electronic Publication: 2020 Mar 20.
DOI: 10.1111/pce.13751
Abstrakt: Stem water storage capacity and hydraulic capacitance (C S ) play a crucial role in tree survival under drought-stress. To investigate whether C S adjusts to increasing water deficit, variation in stem water content (StWC) was monitored in vivo for 2 years and related to periodical measurements of tree water potential in Mediterranean Quercus ilex trees subjected either to permanent throughfall exclusion (TE) or to control conditions. Seasonal reductions in StWC were larger in TE trees relative to control ones, resulting in greater seasonal C S (154 and 80 kg m -3 MPa -1 , respectively), but only during the first phase of the desorption curve, when predawn water potential was above -1.1 MPa. Below this point, C S decreased substantially and did not differ between treatments (<20 kg m -3 MPa -1 ). The allometric relationship between tree diameter and sapwood area, measured via electrical resistivity tomography, was not affected by TE. Our results suggest that (a) C S response to water deficit in the drought-tolerant Q. ilex might be more important to optimize carbon gain during well-hydrated periods than to prevent drought-induced embolism formation during severe drought stress, and (b) enhanced C S during early summer does not result from proportional increases in sapwood volume, but mostly from increased elastic water.
(© 2020 John Wiley & Sons Ltd.)
Databáze: MEDLINE
Externí odkaz: