1. Vulnerability and hydraulic segmentations at the stem‐leaf transition: Coordination across Neotropical trees
- Author
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Sabrina Coste, Charlotte Guichard, Sylvain Delzon, Camille Ziegler, Emma Calvet, Clément Stahl, Patrick Heuret, Sébastien Levionnois, Camille Salmon, Steven Jansen, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Ecologie des forêts de Guyane (UMR ECOFOG), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-AgroParisTech-Université de Guyane (UG)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Universität Ulm - Ulm University [Ulm, Allemagne], Ecologie des forêts de Guyane (ECOFOG), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université des Antilles et de la Guyane (UAG)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Biodiversité, Gènes & Communautés (BioGeCo), Université de Bordeaux (UB)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS), FEDER 20142020. Grant Number: Project GY0006894, ANR-11-LABX-0002,ARBRE,Recherches Avancées sur l'Arbre et les Ecosytèmes Forestiers(2011), and ANR-10-LABX-0025,CEBA,CEnter of the study of Biodiversity in Amazonia(2010)
- Subjects
0106 biological sciences ,0301 basic medicine ,Tropical trees ,Rainforest ,Physiology ,Vulnerability segmentation ,Vulnerability ,Soil science ,Plant Science ,Biology ,Hydraulic resistance ,[SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy ,01 natural sciences ,Trees ,03 medical and health sciences ,[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems ,Xylem ,Segmentation ,Hydraulic segmentation ,Resistance (ecology) ,Plant Stems ,Drought resistance ,fungi ,Drought‐induced embolism resistance ,Water ,food and beverages ,15. Life on land ,[SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics ,Stem‐leaf transition ,Droughts ,French Guiana ,Plant Leaves ,030104 developmental biology ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,Tree species ,Leaf‐specific conductivity ,010606 plant biology & botany - Abstract
International audience; Hydraulic segmentation at the stem-leaf transition predicts higher hydraulic resistance in leaves than in stems. Vulnerability segmentation, however, predicts lower embolism resistance in leaves. Both mechanisms should theoretically favour runaway embolism in leaves to preserve expensive organs such as stems, and should be tested for any potential coordination. We investigated the theoretical leaf-specific conductivity based on an anatomical approach to quantify the degree of hydraulic segmentation across 21 tropical rainforest tree species. Xylem resistance to embolism in stems (flow-centrifugation technique) and leaves (optical visualisation method) was quantified to assess vulnerability segmentation. We found a pervasive hydraulic segmentation across species, but with a strong variability in the degree of segmentation. Despite a clear continuum in the degree of vulnerability segmentation, eight species showed a positive vulnerability segmentation (leaves less resistant to embolism than stems), while the remaining species studied exhibited a negative or no vulnerability segmentation. The degree of vulnerability segmentation was positively related to the degree of hydraulic segmentation, such that segmented species promote both mechanisms to hydraulically decouple leaf xylem from stem xylem. To what extent hydraulic and vulnerability segmentation determine drought resistance requires further integration of the leaf-stem transition at the whole-plant level, including both xylem and outer-xylem tissue.
- Published
- 2020