root's ability to retain K⁺ correlates with salt tolerance in wheat

• Published in: Journal of experimental botany Vol. 59; no. 10; pp. 2697 - 2706
• Main Authors: Cuin, Tracey Ann, Betts, Stewart A, Chalmandrier, Rémi, Shabala, Sergey
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.07.2008; Oxford Publishing Limited (England)
• Subjects: Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Barley; Biological and medical sciences; Biomass; Cell Membrane - physiology; Depolarization; durum wheat; Ears; Flag leaf; Fluctuations; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; genotype; Genotypes; Greenhouses; homeostasis; ions; leaves; Phenotype; Physiology; Plant breeding; plant response; Plant roots; Plant Roots - genetics; Plant Roots - physiology; Plants; Potassium - metabolism; Research Papers; roots; Salinity; Salt tolerance; salts; Seedlings; shoots; Sodium chloride; Sodium Chloride - metabolism; Triticum - genetics; Triticum - physiology; Varietal selection. Specialized plant breeding, plant breeding aims; Wheat; salinity; sodium; screening; wheat; potassium; Microelectrode ion flux; Root; Tolerance; Salinity
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/ern128

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.