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Effects of potassium and sodium supply on drought‐adaptive mechanisms in E ucalyptus grandis plantations
Author(s) -
BattieLaclau Patricia,
Laclau JeanPaul,
Domec JeanChristophe,
Christina Mathias,
Bouillet JeanPierre,
Cassia Piccolo Marisa,
Moraes Gonçalves José Leonardo,
Moreira Rildo Moreira e,
Krusche Alex Vladimir,
Bouvet JeanMarc,
Nouvellon Yann
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12810
Subject(s) - throughfall , environmental science , agronomy , stomatal conductance , biomass (ecology) , sowing , canopy , water use , transpiration , potassium , biology , botany , chemistry , photosynthesis , organic chemistry
Summary 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 ( N a) nutrition on tree structural and physiological adjustments to water deficit. Regardless of the water supply, K and N a supply greatly increased growth and leaf area index ( LAI ) of E ucalyptus 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 N a 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.