Photosynthetic and anatomical responses of Eucalyptus grandis leaves to potassium and sodium supply in a field experiment

Photosynthetic and anatomical responses of Eucalyptus grandis leaves to potassium and sodium supply in a field experiment

Although vast areas in tropical regions have weathered soils with low potassium (K) levels, little is known about the effects of K supply on the photosynthetic physiology of trees. This study assessed the effects of K and sodium (Na) supply on the diffusional and biochemical limitations to photosynthesis in Eucalyptus grandis leaves. A field experiment comparing treatments receiving K (+K) or Na (+Na) with a control treatment (C) was set up in a K-deficient soil. The net CO2 assimilation rates were twice as high in +K and 1.6 times higher in +Na than in the C as a result of lower stomatal and mesophyll resistance to CO2 diffusion and higher photosynthetic capacity. The starch content was higher and soluble sugar was lower in +K than in C and +Na, suggesting that K starvation disturbed carbon storage and transport. The specific leaf area, leaf thickness, parenchyma thickness, stomatal size and intercellular air spaces increased in +K and +Na compared to C. Nitrogen and chlorophyll concentrations were also higher in +K and +Na than in C. These results suggest a strong relationship between the K and Na supply to E.?grandis trees and the functional and structural limitations to CO2 assimilation rates.

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Bibliographic Details
Main Authors: Battie Laclau, Patricia, Laclau, Jean-Paul, Beri, Constance, Mietton, Lauriane, Almeida Muniz, Marta R., Cersózimo Arenque, Bruna, De Cassia Piccolo, Marisa, Jordan-Meille, Lionel, Bouillet, Jean-Pierre, Nouvellon, Yann
Format: article biblioteca
Language:eng
Subjects:K10 - Production forestière, F04 - Fertilisation, F62 - Physiologie végétale - Croissance et développement, F50 - Anatomie et morphologie des plantes, Eucalyptus grandis, plantation forestière, photosynthèse, fertilisation, potassium, sodium, analyse de tissu foliaire, feuille, morphologie végétale, séquestration du carbone, http://aims.fao.org/aos/agrovoc/c_2693, http://aims.fao.org/aos/agrovoc/c_3048, http://aims.fao.org/aos/agrovoc/c_5812, http://aims.fao.org/aos/agrovoc/c_10795, http://aims.fao.org/aos/agrovoc/c_6139, http://aims.fao.org/aos/agrovoc/c_7145, http://aims.fao.org/aos/agrovoc/c_36521, http://aims.fao.org/aos/agrovoc/c_4243, http://aims.fao.org/aos/agrovoc/c_13434, http://aims.fao.org/aos/agrovoc/c_331583, http://aims.fao.org/aos/agrovoc/c_1070,
Online Access:http://agritrop.cirad.fr/571922/
http://agritrop.cirad.fr/571922/1/document_571922.pdf
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Summary:Although vast areas in tropical regions have weathered soils with low potassium (K) levels, little is known about the effects of K supply on the photosynthetic physiology of trees. This study assessed the effects of K and sodium (Na) supply on the diffusional and biochemical limitations to photosynthesis in Eucalyptus grandis leaves. A field experiment comparing treatments receiving K (+K) or Na (+Na) with a control treatment (C) was set up in a K-deficient soil. The net CO2 assimilation rates were twice as high in +K and 1.6 times higher in +Na than in the C as a result of lower stomatal and mesophyll resistance to CO2 diffusion and higher photosynthetic capacity. The starch content was higher and soluble sugar was lower in +K than in C and +Na, suggesting that K starvation disturbed carbon storage and transport. The specific leaf area, leaf thickness, parenchyma thickness, stomatal size and intercellular air spaces increased in +K and +Na compared to C. Nitrogen and chlorophyll concentrations were also higher in +K and +Na than in C. These results suggest a strong relationship between the K and Na supply to E.?grandis trees and the functional and structural limitations to CO2 assimilation rates.

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