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Xylem ionic relations and salinity tolerance in barley.
Shabala, Sergey; Shabala, Svetlana; Cuin, Tracey A; Pang, Jiayin; Percey, William; Chen, Zhonghua; Conn, Simon; Eing, Christian; Wegner, Lars H.
Afiliación
  • Shabala S; School of Agricultural Science, University of Tasmania, Hobart, Tas 7001, Australia. Sergey.Shabala@utas.edu.au
Plant J ; 61(5): 839-53, 2010 Mar.
Article en En | MEDLINE | ID: mdl-20015063
Control of ion loading into the xylem has been repeatedly named as a crucial factor determining plant salt tolerance. In this study we further investigate this issue by applying a range of biophysical [the microelectrode ion flux measurement (MIFE) technique for non-invasive ion flux measurements, the patch clamp technique, membrane potential measurements] and physiological (xylem sap and tissue nutrient analysis, photosynthetic characteristics, stomatal conductance) techniques to barley varieties contrasting in their salt tolerance. We report that restricting Na(+) loading into the xylem is not essential for conferring salinity tolerance in barley, with tolerant varieties showing xylem Na(+) concentrations at least as high as those of sensitive ones. At the same time, tolerant genotypes are capable of maintaining higher xylem K(+)/Na(+) ratios and efficiently sequester the accumulated Na(+) in leaves. The former is achieved by more efficient loading of K(+) into the xylem. We argue that the observed increases in xylem K(+) and Na(+) concentrations in tolerant genotypes are required for efficient osmotic adjustment, needed to support leaf expansion growth. We also provide evidence that K(+)-permeable voltage-sensitive channels are involved in xylem loading and operate in a feedback manner to maintain a constant K(+)/Na(+) ratio in the xylem sap.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Sodio / Hordeum / Xilema / Plantas Tolerantes a la Sal Idioma: En Revista: Plant J Asunto de la revista: BIOLOGIA MOLECULAR / BOTANICA Año: 2010 Tipo del documento: Article País de afiliación: Australia Pais de publicación: Reino Unido

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Sodio / Hordeum / Xilema / Plantas Tolerantes a la Sal Idioma: En Revista: Plant J Asunto de la revista: BIOLOGIA MOLECULAR / BOTANICA Año: 2010 Tipo del documento: Article País de afiliación: Australia Pais de publicación: Reino Unido