Effects of potassium and sodium supply on drought-adaptive mechanisms in Eucalyptus grandis plantations
Battie-Laclau, Patricia | Laclau, Jean-Paul | Domec, Jean-Christophe | Christina, Mathias | Bouillet, Jean-Pierre | de Cassia Piccolo, Marisa | de Moraes Gonçalves, José Leonardo | Moreira, Rildo Moreira E | Krusche, Alex Vladimir | Bouvet, Jean-Marc | Nouvellon, Yann | Centro de Energia Nuclear na Agricultura ; Universidade de São Paulo = University of São Paulo (USP) | Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Departamento de Ciencia Florestal ; Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP) | Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ) ; Universidade de São Paulo = University of São Paulo (USP) | Interactions Sol Plante Atmosphère (UMR ISPA) ; Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro) | Nicholas School of the Environment ; Duke University [Durham] | Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Departamento de Ciências Atmosféricas ; Universidade de São Paulo = University of São Paulo (USP) | FAPESP (www.fapesp.br, 2010/50663-8), CIRAD, USP-COFECUB (Project 2011-25), AGREENIUM (Plantotrem project), SOERE F-ORE-T. Additional support was provided by the US Department of Energy Terrestrial Ecosystem Sciences program (11-DE-SC-0006700), the National Science Foundation (NSF IOS-1146746 and NSF EAR-1344703) and USDA-NIFA.
A basic understanding of nutrition effects on the mechanisms involved in tree response to drought is essential under a future drier climate. * A large-scale throughfall exclusion experiment was set up in Brazil to gain an insight into the effects of potassium (K) and sodium (Na) nutrition on tree structural and physiological adjustments to water deficit. * Regardless of the water supply, K and Na supply greatly increased growth and leaf area index (LAI) of Eucalyptus grandis trees over the first 3 yr after planting. Excluding 37% of throughfall reduced above-ground biomass accumulation in the third year after planting for K- supplied trees only. E. grandis trees were scarcely sensitive to drought as a result of the utilization of water stored in deep soil layers after clear-cutting the previous plantation. Trees coped with water restriction through stomatal closure (isohydrodynamic behavior), osmotic adjustment and decrease in LAI. Additionally, droughted trees showed higher phloem sap sugar concentrations. * K and Na supply increased maximum stomatal conductance, and the high water requirements of fertilized trees increased water stress during dry periods. Fertilization regimes should be revisited in a future drier climate in order to find the right balance between improving tree growth and limiting water shortage.
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