Ion distribution in wheat cultivars in response to salinity stress

In a pot experiment, 30 cultivars of wheat (Triticum aestivum L.) were evaluated in terms of their leaf and grain K/Na ratios and their ion selectivity responses to NaCl salinity. A completely randomized block design with factorial treatments in three replications was employed. Tap water, both with and without NaCl, producing a soil extract EC of 16 ds m(-1) was used as the salinity treatment, beginning at the stem elongating stage. Significant correlations observed between grain dry matter (DM) and some ionic traits indicate that, beside the adverse effects of the higher leaf Na concentration on grain DM, the processes involved in the rate and/or duration of grain filling may be more efficient in terms of salt tolerance where grain yield is concerned. This may allow for the reproductive phase of growth to be salt tolerant independently of the vegetative one. Cultivar Inia-66 could serve as an example of this, showing higher rates of salt tolerance through the more suitable DM partitioning pattern. Mean comparisons made between the cultivars showed that the salt tolerant Roshan cultivar and, 10 other following cultivars, had the highest rates of absolute salt tolerance. This cultivar had the lowest leaf Na concentration, the highest K versus Na selectivity in ion transport from the soil to the grains, and also the highest grain K/Na ratios. It produced grain DM 7.5 times higher than the salt sensitive Ghods cultivar that had the lowest grain DM. The former 11 cultivars could therefore be considered as the most completely salt tolerant cultivars. In the cultivar Kharchia, salinity did not reduce the grain K/Na ratio and ion selectivity, but its grain filling period and HI were reduced under saline conditions. (C) 2003 Elsevier B.V. All rights reserved.