Na+/K+ selectivity of leaf sheath in wheat cultivars differing in salt tolerance

A salt-tolerant wheat cultivar (DK961) and a salt-sensitive one (LM15) were exposed to 200 mmol/L NaCl for 3 d to study selectivity in transport of K(+) and Na(+) of the leaf sheath. Na(+) content of leaf sheath and K(+) content of leaf blade of DK961 were significantly higher than those of LM15, which led to a lower Na(+)/K(+) ratio of leaf blade of DK961 than that of LM15. These results suggested that leaf sheath of DK961 had much stronger abilities of limiting Na(+) transport and allowing K(+) transport from leaf sheath to leaf blade than that of LM15 to maintain lower Na(+)/K(+) ratio of leaf blade under NaCl stress, indicating that leaf sheath may play an important role in wheat salt tolerance.