Considering that plants experiencing saline–alkaline stress have to counteract excess toxic Na+ (Zhang et al., 2015), the effects of saline–alkaline stress on Na+ and K+ concentrations as well as Na+/K+ ratios in plants were investigated. Before saline–alkaline treatment, no significant difference was observed between the non-inoculated and inoculated plants (Figure 3). After 2 and 4 weeks of the stress treatment, shoot K+ concentrations of the inoculated plants were 33 and 45% higher than that of the non-inoculated plants [Figure 3A; F(5,54) = 122.69, P < 0.05], and root K+ concentrations were 67 and 75% higher [Figure 3B; F(5,54) = 171.30, P < 0.05], respectively. On the contrary, shoot Na+ concentrations of the inoculated plants were 35 and 42% lower than those of the non-inoculated plants [Figure 3C; F(5,54) = 290.86, P < 0.05], and root Na+ concentrations of the inoculated plants were 30 and 56% lower [Figure 3D; F(5,54) = 510.83, P < 0.05], respectively. These further led to higher ratio of Na+/K+ in shoots [Figure 3E; F(5,54) = 426.03, P < 0.05] and roots [Figure 3F; F(5,54) = 640.31, P < 0.05] the non-inoculated plants than that of the inoculated plants under saline–alkaline stress, respectively.