期刊
NEW PHYTOLOGIST
卷 203, 期 2, 页码 401-413出版社
WILEY
DOI: 10.1111/nph.12810
关键词
drought; eucalypt; nutrition; osmotic adjustment; rainfall exclusion; stomatal conductance; water deficit
资金
- FAPESP [2010/50663-8]
- CIRAD
- USP-COFECUB [2011-25]
- AGREENIUM (Plantotrem project)
- SOERE F-ORE-T
- US Department of Energy Terrestrial Ecosystem Sciences program [11-DE-SC-0006700]
- National Science Foundation [NSF IOS-1146746, NSF EAR-1344703]
- USDA-NIFA
- Division Of Integrative Organismal Systems
- Direct For Biological Sciences [1462486] Funding Source: National Science Foundation
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 3yr 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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