Selenium Biofortification of Three Wild Species, Rumex acetosa L., Plantago coronopus L., and Portulaca oleracea L., Grown as Microgreens

Microgreens of wild herbs are a source of healthy compounds. Selenium (Se) biofortification of microgreens could help increase the Se content and thus contribute to Se requirements in humans. We evaluated whether three wild herbs, Rumex acetosa L., Plantago coronopus L., and Portulaca oleracea L., were suitable for biofortification in order to obtain products with high nutraceutical value. In the first experiment, the three species were enriched with Na2SeO4 at 0 and 1.5 mg Se L−1, and the effects of Se on the nutraceutical characteristics of microgreens were evaluated. In the second experiment, using P. oleracea enriched with 0, 1.5, 5, and 10 mg Se L−1, we investigated whether there was a relation between the increasing Se concentrations in the nutrient solution and the Se content in microgreens. The Se added was taken up by roots and accumulated in the aerial part. P. coronopus exhibited the highest ability to accumulate selenium, and the Se-enriched microgreens showed the highest chlorophyll and flavonoid content. The strong correlation between the Se concentration in the growth solution and the Se accumulated in P. oleracea may enable the cultivation of microgreens with the targeted Se content. The resulting Se-biofortified microgreens of wild species could represent a new vegetable product with high nutraceutical value also ensuring a sufficient dietary intake of Se.