Plant growth and productivity is tightly associated with adverse conditions, which cause a marked decrease in plant photosynthesis, thereby affecting its productivity (Li et al., 2016; Zhou et al., 2016b). In this study, in addition to greater biomass, the SA03-inoculated plants displayed higher chlorophyll content under saline–alkaline stress, which possibly led to stronger photosynthetic capacity. This positive effect may improve the growth performance of inoculated plants under saline–alkaline stress. A great photosynthetic efficiency in plants indicates that the photosynthetic apparatus is not considerably damaged by saline–alkaline treatment (Gong et al., 2014). It has recently been shown that the structural and functional integrity of chloroplasts are seriously destroyed by saline–alkaline stress (Li et al., 2016). In this study, the stress-treated plants displayed leaf chlorosis, indicating a serious disturbance of normal chloroplast development. Saline–alkaline stress has recently been shown to reduce the contents of chlorophyll and affect normal chloroplast development (Gong et al., 2014). Here, the inoculation with SA03 conspicuously lessened oxidative damages to chloroplast ultrastructure caused by saline–alkaline stress to a large extent, thereby leading to high photosynthetic efficiency. Furthermore, the non-inoculated plants exhibited the increased values of ROS and MDA under saline–alkaline stress, whereas their values were markedly lower in the inoculated plants. Additionally, the EL levels were relatively lower in the inoculated plants than the non-inoculated plants. Consistently, the inoculated plants owned higher ROS-detoxifying enzymatic activities than the non-inoculated plants. Ample evidence has indicated that the enhanced activities of antioxidant enzymes play important roles in modulating ROS levels in plants under adverse stresses (Gong et al., 2014; Wei L. et al., 2015; Zhou et al., 2016b). Therefore, these findings indicated that the inoculation with SA03 can alleviate oxidative damage imposed by saline–alkaline stress.