Industrial Hemp Finola Variety Microgreens: A Sustainable Source of Selenium Biofortified Functional Foods

The aim of this study was to evaluate the effects of selenium (Se) biofortification on growth, biomass accumulation, and micronutrient composition of industrial hemp (<i>Cannabis sativa</i> L., cv. Finola) microgreens, with emphasis on Se uptake and its distribution among leaves, stems, and roots. Microgreens were subjected to four Se treatments (Se_0, Se_2, Se_4, and Se_6 µmol Se/L), and changes in morphological traits, micronutrient status (Mn, Fe, Cu, Zn), and Se accumulation were assessed. Selenium biofortification had a marked impact on plant morphology and biomass. Stem length decreased by 12–18% under Se treatments compared with the control, whereas root length increased slightly, particularly at Se_2 and Se_4 (up to +6%). Fresh industrial hemp microgreens biomass responded strongly to Se supply, with the highest stem, root, and total fresh mass recorded at Se_4—representing an increase of 15–22% relative to control plants. At the highest Se level (Se_6), biomass declined by approximately 10–14%, indicating potential growth inhibition at excessive Se concentrations. Micronutrient concentrations were significantly affected by Se. Leaf Mn increased from 152 mg kg⁻¹ at Se_0 to 175 mg kg⁻¹ at Se_6 (+15%), while leaf Zn decreased by 20–25% at higher Se exposure. Stems and roots showed similar antagonistic interactions, with Fe and Zn decreasing by up to 30% at elevated Se levels. Conversely, Mn in stems and roots increased with Se up to Se_4, reaching 400 mg kg⁻¹ in roots. Selenium accumulation exhibited a strong linear response to biofortification, with high coefficients of determination (R² = 0.9685–0.9943), confirming predictable and efficient Se uptake. Correlation analysis revealed strong positive associations among biomass-related traits and distinct interactions among micronutrients, especially the near-perfect correlation between Se and Cu in roots (r ≈ 0.99). Overall, industrial hemp microgreens demonstrate potential for selenium biofortification, provided that selenium application levels remain within safe dietary limits.