Selenium-sulphur effects on the chemical composition of alfalfa (Medicago sativa L. cv. Verko)

Selenium (Se) is an essential micronutrient, and the ability of some crops to accumulate Se is crucial for human and animal nutrition and health. Se deficiency can cause white muscle disease characterized by muscle weakness, heart failure, unthriftiness, and death in livestock. This study was undertaken to investigate the effect of sulphur (S) on Se concentration in alfalfa (Medicago sativa L. cv. Verko) as a nonhyperaccumulator plant. Alfalfa plants grown in the field were treated foliarly with 3 g Se ha⁻¹ solutions of selenate, 3 g S ha⁻¹ sulphate, and both. The concentration of Se in both the leaves and stems of plants was similar in the control and S-treated plants. Se concentration in plants treated with S was undetectable, as expected. S was shown to enhance Se accumulation in alfalfa. Furthermore, although foliar Se + S spray increased biomass, photosynthetic pigments decreased peroxidase activity and malondialdehyde content. Overall, results suggested that foliar Se + S spray can be applied as a biofortification to improve alfalfa plants with appropriate amounts of Se and better nutritional as well as functional quality.