Photosynthetic and anatomical responses of Eucalyptus grandis leaves to potassium and sodium supply in a field experiment.
Plant Cell Environ
; 37(1): 70-81, 2014 Jan.
Article
em En
| MEDLINE
| ID: mdl-23663049
ABSTRACT
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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Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Fotossíntese
/
Potássio
/
Sódio
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Folhas de Planta
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Eucalyptus
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article