sensitivity of Sakha 102 might be due to the repression of OsHKT1;5
expression, thus leading to unregulated Naþ transport to the leaves
and growth impairment (Fig. 1). By comparing the patterns of Naþ
accumulation in the tolerant and sensitive cultivars under salt
stress conditions, Cotsaftis et al. (2012) reported that OsHKT1;4 (an
OsHKT1;5 homolog), may participate in a Naþ retrieving mechanism
in rice leaf sheaths. Therefore, we also investigated the
expression profiles of OsHKT1;4 in both Egyptian Yasmine and
Sakha 102. Under salt stress, expression of OsHKT1;4 was not
affected in the leaves, sheaths, or roots of either cultivar (data not
shown), which suggests that the function of Naþ retrieval in
sheaths did not contribute to the restriction of Naþ accumulation in
the leaves of either cultivar.