Abstract: 【Objective】 To clarify the relationship between salt stress response and K+ uptake in plants, dynamic change of K+ uptake in SOS mutants under salt stress was investigated by using three Arabidopsis mutants of sos1, sos2, and sos3 involved in the SOS signal pathway as materials.【Method】 The Arabidopsis mutants materials plus the wild type (WT) were treated on MS medium containing various concentration ratios of Na+/K+, then their phenotypes in plant appearances were observed and analyzed by comparison. Also their roots scanning, RGR (relative growth rate), Na+, and K+ content, and Na+/K+ ratio in vivo were tested. Furthermore, the expression difference of K+ transporter genes such as AKT1, AKT2 and SKOR between the materials was identified by qRT-PCR. 【Result】No significant difference was found in the above explored traits between the mutants and WT when they were cultured on the MS medium with different concentrations of K+. In the treatment of 30 mmol•L-1 NaCl and the range of 0.2-60 mmol•L-1 K+, the increase of K+ concentration alleviated the growth inhibition of the mutants caused by high salt stress, and reduced the Na+/K+ ratio and enhanced the K+ concentration in vivo in all materials. Under a fixed treatment, Na+/K+ ratio was higher in the mutants than in WT, but K+ concentration was higher in WT than in the mutants. However, when K+ up to 80 mmol•L-1 in medium the growth of the mutants was inhibited again, and at the same time Na+/K+ ratio increased and K+ decreased in vivo of all plants. Real-time PCR analysis showed that the expression of AKT1 and SKOR was relatively low under the condition of 30 mmol•L-1 NaCl and low concentration potassium (0.2 mmol•L-1 K+). Under 30 mmol•L-1 NaCl and high concentration potassium (20.05 mmol•L-1 K+ or 60 mmol•L-1 K+), the expressions of AKT1, AKT2 and SKOR appeared no significant difference and their expression patterns were almost similar in different mutants. 【Conclusion】 Under moderate salt stress conditions, growth suppression of the plants caused by the salt stress could be alleviated with the increase of K+ concentration. But, when the concentration of external univalence cation was over 110 mmol•L-1, the growth status of the plants was restrained again. Therefore, it was speculated that SOS signaling pathway was not involved in the regulation of absorption and transport of K+ directly.

Key words: SOS pathway , K+ absorption , high-salt stress , Na+ / K+ concentration ratio , K+ transporter