To inspect whether the inoculated of plants with SA03 could confront oxidative stress imposed by saline–alkaline treatment, we measured the content of two major types of ROS including O2•– and H2O2 in leaves of plants. Before saline–alkaline treatment, a slight increase of O2•– [F(5,54) = 160.58, P < 0.05] and H2O2 [F(5,54) = 213.56, P < 0.05] levels was observed in the inoculated plants compared with the non-inoculated plants (Figures 4A,B). However, the values of MDA and EL, important indicators of oxidative damage, in both the non-inoculated and inoculated plants did not differ significantly (Figures 4C,D). After 2 and 4 weeks of the stress treatment, the content of O2•– and H2O2 was markedly increased, especially in the 4-week treatment. By contrast, the inoculated plants displayed markedly lower content of O2•– and H2O2. Consistent with this, saline–alkaline treatment considerably induced a great increase of MDA in plants. However, the leaves of inoculated plants had 36 and 32% lower MDA content than that of the non-inoculated plants under the stress, respectively [Figure 4C; F(5,54) = 311.48, P < 0.05]. Similarly, soil inoculation markedly decreased the EL levels in the leaves of inoculated plants under the stress compared with the non-inoculated plants [Figure 4D; F(5,54) = 253.81, P < 0.05].