Figure 4.

Net Na⁺ effluxes from root elongation and mature zones of the three rice cultivars. (A) Roots were exposed to 0 (control) or 100 mM NaCl (NaCl) for 24 h and then transferred to basic salt media (BSM) solution without 100 mM NaCl for 30 min. Net steady-state fluxes were measured for 3–5 min. (B) Net Na⁺ effluxes were measured from elongation root zone of cultivar Reiziq without (control) or with inhibitors: 1 mM sodium orthovanadate (vanadate) (a known blocker of the plasma membrane H⁺-ATPase), 1 mM amiloride (an inhibitor of the plasma membrane Na⁺/H⁺ exchanger activity). Rice roots were pretreated with the inhibitors for 1 h. Quantitative reverse transcription PCR (qRT-PCR) analysis of the time-dependent expression pattern of OsSOS1 (C, D), OsSOS2 (E, F) in the root tips (C, E), and mature zones (D, F) of the three cultivars. Asterisk * or ** indicate a significant difference between tissues at P < 0.05 or P < 0.01, respectively.