Salt Stress Changes the Ion Homeostasis via Differential K+ Uptake Ways in Salt-Sensitive/Tolerant Wheat (Triticum aestivum) Varieties

The capacity of K+ acquisition and retention in wheat (Triticum aestivum L.) roots is related to salt tolerance. Salt-tolerant 'C6005' and salt-sensitive 'AK58' wheat cultivars were used with combined treatment of NaCl stress and K+ transport blockers to study the effect of salt stress on ion homeostasis. NaCl induced an apparent decline of K+/Na+ ratios in two wheat cultivars. The K+/Na+ ratio in 'C6005' was higher than that in 'AK58'. Inhibitors TEA (Tetraethylammonium chloride), NEM (N-ethylmaleimide) and Ba (NO3)(2) all influenced the transport and accumulation of K+ and Na in root and leaf tissues, and NEM exhibited the most obvious effects. Combined NEM and NaCl treatment induced the highest K+ efflux and the value of K+ efflux in 'AK58' was higher than that in 'C6005'. Level of 250 mM NaCl increased the activity of K+/H+ transporters in 'C6005' but decreased that in 'AK58'. NaCl decreased the K-in(+) currents in root protoplast and the amplitude of K-in(+) currents in 'AK58' was more obvious than that in 'C6005'. NaCl stress up-regulated the expression of HAK5 in roots of both cultivars, the trend in 'C6005' with combined NEM and NaCl treatment at 48 h was most evident. This work concluded that the K+ transporters may be more important way to absorb K+ compared to other two ways. The regulation of HAK5 expression at transcript level could play a key role in the ion homeostasis in wheat roots. (C) 2019 Friends Science Publishers