Serotonin alleviates selenium stress by reducing selenium uptake in grapevines

Abstract External application of serotonin (SER) was investigated to determine its effect on grapevine growth and selenium (Se) uptake under Se stress conditions. The treatment of Se (0.5 mg L −1 ) decreased the biomass, photosynthetic pigment content, and superoxide dismutase (SOD) activity of grapevines, and increased the activities of peroxidase (POD) and catalase (CAT), suggesting a stress induction caused by Se. Under Se stress, SER treatment (150 μmol L −1 ) increased root and shoot biomass of grapevines by 6.83% and 9.25%, respectively, compared to Se treatment. SER treatment also increased the levels of chlorophyll a and total chlorophylls by 7.15% and 4.75%, respectively, compared to Se treatment, while it did not affect the levels of chlorophyll b and carotenoid under Se stress. However, SER treatment did not affect the activities of SOD and CAT, while increasing POD activity under Se stress. Notably, SER treatment decreased root and shoot total Se contents by 9.78% and 29.34%, respectively, compared to Se treatment, and reduced Se translocation from roots to shoots. Additionally, shoot total Se content demonstrated strong correlations with POD activity, SOD activity, and root total Se content. Therefore, SER can alleviate Se stress, promote growth, and reduce Se uptake of grapevines.