The presence of moderate salt can increase tolerance of Elaeagnus angustifolia seedlings to waterlogging stress.

High salinity and waterlogging are two stress factors that often occur simultaneously in nature, particularly during the rainy season in the Yellow River Delta (YRD) of China. An attractive approach to improve the saline-alkali soil produced by waterlogging and high salt is to use plants for wetland ecosystem restoration. In this work, we examined the ecological adaptability of Elaeagnus angustifolia L. under combined waterlogging and salt stress, to evaluate the potential of this species for introduction to the YRD. We monitored the effects of salt plus waterlogging co-stress on the anatomy, physiology, and enzymatic systems in E. angustifolia seedlings. Salt alone and waterlogging alone inhibited the growth of the seedlings, while salt plus waterlogging co-stress reduced this growth inhibition. Furthermore, E. angustifolia seedlings resisted the salt plus waterlogging co-stress by increasing porosity, accumulating more inorganic ions and organic solutes, and increasing antioxidant enzyme activities to maintain high photosynthetic rates and membrane stability and thus avoid damage. These findings support the inclusion of E. angustifolia in the ecological restoration of the YRD.