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

摘要

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 (NO 3 ) 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.