title: How adaptable is the hydraulic system of European beech in the face of climate change-related precipitation reduction?
abstract: Climate warming will increase the drought exposure of many forests world-wide. It is not well understood how trees adapt their hydraulic architecture to a long-term decrease in water availability. We examined 23 traits characterizing the hydraulic architecture and growth rate of branches and the dependent foliage of mature European beech (Fagus sylvatica) trees along a precipitation gradient (855-594 mm yr(-1) ) on uniform soil. A main goal was to identify traits that are associated with xylem efficiency, safety and growth. Our data demonstrate for the first time a linear increase in embolism resistance with climatic aridity (by 10%) across populations within a species. Simultaneously, vessel diameter declined by 7% and pit membrane thickness (Tm ) increased by 15%. Although specific conductivity did not change, leaf-specific conductivity declined by 40% with decreasing precipitation. Of eight plant traits commonly associated with embolism resistance, only vessel density in combination with pathway redundancy and Tm were related. We did not confirm the widely assumed trade-off between xylem safety and efficiency but obtained evidence in support of a positive relationship between hydraulic efficiency and growth. We conclude that the branch hydraulic system of beech has a distinct adaptive potential to respond to a precipitation reduction as a result of the environmental control of embolism resistance.
authors.affiliation: Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073, Göttingen, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schuldt
authors.affiliation: Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073, Göttingen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Knutzen
authors.affiliation: UMR BIOGECO INRA-UB, University of Bordeaux, Avenue des Facultés, 33405, Talence, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Delzon
authors.affiliation: Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
authors.forename: Steven
authors.initials: S
authors.lastname: Jansen
authors.affiliation: Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073, Göttingen, Germany.
authors.forename: Hilmar
authors.initials: H
authors.lastname: Müller-Haubold
authors.affiliation: UMR BIOGECO INRA-UB, University of Bordeaux, Avenue des Facultés, 33405, Talence, France.
authors.forename: Régis
authors.initials: R
authors.lastname: Burlett
authors.affiliation: Centre for Environmental and Climate Research, Faculty of Science, Lund University, Sölvegatan 37, 223 62, Lund, Sweden.
authors.forename: Yann
authors.initials: Y
authors.lastname: Clough
authors.affiliation: Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073, Göttingen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Leuschner
mesh_terms: D000222:Adaptation, Physiological; D057231:Climate Change; D005060:Europe; D029964:Fagus / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D016014:Linear Models; D018515:Plant Leaves / Q000502:physiology; D018547:Plant Stems / Q000254:growth & development; D011312:Pressure; D025341:Principal Component Analysis; D011891:Rain; D014934:Wood / Q000032:analysis / Q000502:physiology; D052584:Xylem / Q000502:physiology
keywords: drought stress; functional trait; hydraulic conductivity; leaf morphology; pit membrane; precipitation gradient; vulnerability to cavitation; wood anatomy