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Título

High-affinity potassium and sodium transport systems in plants

AutorRodríguez-Navarro, Alonso; Rubio, Francisco
Palabras clavePotassium transport
Sodium transport
Fecha de publicación31-ene-2006
EditorOxford University Press
CitaciónJournal Experimental Botany 57(5): 1149-1160(2006)
ResumenAll living cells have an absolute requirement for K+, which must be taken up from the external medium. In contrast to marine organisms, which live in a medium with an inexhaustible supply of K+, terrestrial life evolved in oligotrophic environments where the low supply of K+ limited the growth of colonizing plants. In these limiting conditions Na+ could substitute for K+ in some cellular functions, but in others it is toxic. In the vacuole, Na+ is not toxic and can undertake osmotic functions, reducing the total K+ requirements and improving growth when the lack of K+ is a limiting factor. Because of these physiological requirements, the terrestrial life of plants depends on high-affinity K+ uptake systems and benefits from high-affinity Na+ uptake systems. In plants, both systems have received extensive attention during recent years and a clear insight of their functions is emerging. Some plant HAK transporters mediate high-affinity K+ uptake in yeast, mimicking K+ uptake in roots, while other members of the same family may be K+ transporters in the tonoplast. In parallel with the HAK transporters, some HKT transporters mediate high-affinity Na+ uptake without cotransporting K+. HKT transporters have two functions: (i) to take up Na+ from the soil solution to reduce K+ requirements when K+ is a limiting factor, and (ii) to reduce Na+ accumulation in leaves by both removing Na+ from the xylem sap and loading Na+ into the phloem sap.
Versión del editorhttp://dx.doi.org/10.1093/jxb/erj068
URIhttp://hdl.handle.net/10261/17657
DOI10.1093/jxb/erj068
ISSN1460-2431 (Online)
0022-0957 (Print)
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