Selenium Biofortification of Popcorn Maize Microgreens by Nutri-Priming and Foliar Application

<jats:p>Selenium (Se) biofortification may improve the nutritional value of microgreens, but its effect depends on the chemical form and application method. This study evaluated selenium applied as selenate or selenite through seed nutri-priming, foliar application, or their combination on the growth, biomass, mineral composition, and estimated selenium intake of popcorn maize microgreens. Roots and aboveground tissues were analyzed separately to assess the potential use of both plant parts as sources of nutritionally valuable biomass. Seeds were treated with 40 µmol Se L−1, and microgreens were harvested nine days after sowing. Selenium treatments significantly affected plant growth, fresh biomass, and the concentrations of P, Mn, Fe, Cu, Zn, and Se. Seed nutri-priming with selenite produced the best growth response, with the highest total plant length of 48.5 cm and the highest total fresh mass of 1.31 g per plant. The greatest selenium accumulation was obtained with seed nutri-priming using selenate combined with foliar application, reaching 890.90 µg kg−1 d. m. in roots and 1389.80 µg kg−1 d. m. in leaves. This treatment also resulted in the highest estimated daily intake (EDI), with 1.95 µg day−1 from leaves and 1.25 µg day−1 from roots. In contrast, the lowest EDI values were recorded after hydropriming followed by foliar selenate application, with 0.05 µg day−1 in the leaves and 0.09 µg day−1 in the roots. In general, selenite seed nutri-priming was more suitable for improving growth and biomass, whereas combined selenate application was the most effective strategy for selenium enrichment. The results also indicate that both roots and aboveground tissues may have potential value, although the use of root biomass requires further assessment of selenium bioavailability, safety, and suitability for food applications.</jats:p>