Cerium improves plant growth and fruit quality of strawberry plants under salt stress by changing the antioxidant capacity and water physiology

This study investigated the effects of cerium (Ce) on the growth and fruit quality of strawberries under salt stress. The findings revealed that salt stress markedly enhanced the activities of antioxidant enzymes and increased the contents of malonaldehyde (MDA) and hydrogen peroxide (H2O2) in leaves and the contents of anthocyanins, phenolic compounds, vitamin C (Vc), soluble sugar (SS) and titratable acid (TA) in fruits. Ce markedly improved the activities of ascorbate peroxidase, superoxide dismutase, peroxidase and catalase in leaves and the contents of anthocyanins, phenolic compounds, Vc and SS in fruits, but significantly decreased MDA and H2O2 levels in leaves and TA content in fruits under salt stress. However, salt stress significantly decreased the contents of chlorophyll (Chl) and carotenoids (Car), photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (gs), relative water content (RWC), plant height and biomass, and fruit weight and sugar-acid ratio (SAR). Compared with salt stress alone, Ce obviously increased Chl and Car contents, Pn, Tr, gs, RWC, plant height and biomass, as well as fruit weight and SAR. The above results suggested that Ce showed beneficial effects on the growth and fruit quality of strawberries under salt stress.