JXB Advance Access originally published online on May 20, 2008
Journal of Experimental Botany 2008 59(10):2697-2706; doi:10.1093/jxb/ern128
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© 2008 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)
RESEARCH PAPER |
A root's ability to retain K+ correlates with salt tolerance in wheat
School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia
* To whom correspondence should be addressed. E-mail: Tracey.Cuin{at}utas.edu.au
Most work on wheat breeding for salt tolerance has focused mainly on excluding Na+ from uptake and transport to the shoot. However, some recent findings have reported no apparent correlation between leaf Na+ content and wheat salt tolerance. Thus, it appears that excluding Na+ by itself is not always sufficient to increase plant salt tolerance and other physiological traits should also be considered. In this work, it was investigated whether a root's ability to retain K+ may be such a trait, and whether our previous findings for barley can be extrapolated to species following a ‘salt exclusion’ strategy. NaCl-induced kinetics of K+ flux from roots of two bread and two durum wheat genotypes, contrasting in their salt tolerance, were measured under laboratory conditions using non-invasive ion flux measuring (the MIFE) technique. These measurements were compared with whole-plant physiological characteristics and yield responses from plants grown under greenhouse conditions. The results show that K+ flux from the root surface of 6-d-old wheat seedlings in response to salt treatment was highly correlated with major plant physiological characteristics and yield of greenhouse-grown plants. This emphasizes the critical role of K+ homeostasis in plant salt tolerance and suggests that using NaCl-induced K+ flux measurements as a physiological ‘marker’ for salt tolerance may benefit wheat-breeding programmes.
Key words: Microelectrode ion flux, potassium, salinity, screening, sodium, wheat
Present address: Department of Agriculture, Fisheries and Forestry, 18 Marcus Clarke Street, Canberra City, Australia Capital Territory 2601, Australia.
Present address: Institut Polytechnique, LaSalle Beauvais, BP 30313, 60026 Beauvais, France
Received 17 February 2007; Revised 30 March 2008 Accepted 7 April 2008