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Xylem ionic relations and salinity tolerance in barley


Shabala, SN and Shabala, SI and Cuin, TA and Pang, J and Percey, WJ and Chen, Z and Conn, S and Eing, C and Wegner, LH, Xylem ionic relations and salinity tolerance in barley, The Plant Journal, 61, (5) pp. 839-853. ISSN 0960-7412 (2010) [Refereed Article]

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DOI: doi:10.1111/j.1365-313X.2009.04110.x


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.

Item Details

Item Type:Refereed Article
Keywords:salt stress, xylem sap, potassium, sodium, ion channels, membrane depolarization
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Grains and seeds
Objective Field:Barley
UTAS Author:Shabala, SN (Professor Sergey Shabala)
UTAS Author:Shabala, SI (Associate Professor Lana Shabala)
UTAS Author:Cuin, TA (Dr Tracey Cuin)
UTAS Author:Pang, J (Ms Jiayin Pang)
UTAS Author:Percey, WJ (Mr William Percey)
UTAS Author:Chen, Z (Mr Zhonghua Chen)
ID Code:67748
Year Published:2010
Web of Science® Times Cited:131
Deposited By:Agricultural Science
Deposited On:2011-03-07
Last Modified:2012-10-10
Downloads:1 View Download Statistics

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