Glucose-induced activation of rubidium transport and water flux in sunflower root systems
Excised 20-d-old sunflower roots ( Helianthusannuus L. cv. Sun-Gro 393) were used to study the effect of different sugars on rubidium and water fluxes. The roots sensed and absorbed glucose from the external medium inducing the activation of rubidium accu- mulated in the root (Rb q root), the flux o...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2001 |
| País: | España |
| Institución: | Universidad de Sevilla (US) |
| Repositorio: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:idus.us.es:11441/60261 |
| Acceso en línea: | http://hdl.handle.net/11441/60261 https://doi.org/10.1093/jexbot/52.354.99 |
| Access Level: | acceso abierto |
| Palabra clave: | Exudation rate Helianthus annuus rubidium transport sunflower |
| Sumario: | Excised 20-d-old sunflower roots ( Helianthusannuus L. cv. Sun-Gro 393) were used to study the effect of different sugars on rubidium and water fluxes. The roots sensed and absorbed glucose from the external medium inducing the activation of rubidium accu- mulated in the root (Rb q root), the flux of exuded rubidium ( J Rb ) and, to a lesser degree, the exudation rate ( J v ). These effects were also triggered by fructose, but not by 6-deoxyglucose (6-dG), a glucose analogue which is not a substrate for hexokinase (HXK). The effect of 2-deoxyglucose (2-dG), an analogue that is phosphorylated but not further metabolized, was complex, suggesting an inhibitory effect on solute transport to the xylem. The amounts of glucose required to activate rubidium and water fluxes were similar to those previously reported to regulate different processes in other plants (0.5±10 mM). When sorbitol was used instead of glucose, neither rubidium uptake (Rb q root plus J Rb ) nor J v was activated. It is proposed that glucose present in the root plays an important signalling role in the regulation of Rb q (K q ) and water transport in plant roots |
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