Response of lettuce to Se biofortification under different white LEDs lighting

Selenium (Se) is an essential trace element for human health acting as an antioxidant, helping reduce the risk of chronic and cardiovascular diseases, etc. Enrichment of hydroponic nutrient solution with Se is one of the ways for the enhancement of Se in leafy vegetables. The study aimed to determine the responses of lettuce (Lactuca sativa, ‘Little Gem’) cultivated under different white (3000K, 3500K, 4000K) light-emitting diodes (LED) lighting to Se content in hydroponic solution. The photon flux density (PFD), photoperiod, temperature, and relative humidity in the growth chamber were maintained at 220 mmol m^-2 s^-1, 18 h, 21/17±2°C, and 60±5%, respectively. Se (1 ppm) experiment was performed using sodium selenate (Na₂SeO₄). Results showed that the significantly higher Se content and translocation factor was determined under 3500K LEDs. Meanwhile, the bioconcentration factor was lower under this lighting. Se negatively affected sulphur content under whole white LEDs lighting but had no significant impact on other mineral element content. Lettuce growth was more dependent on light but not Se content in the hydroponic solution. The most positive effect on their growth was determined under 3000K LEDs. The highest content of fructose and glucose was under 3500 LEDs. Se exposure increased DPPH under 4000K LEDs but did not affect FRAP and ABTS under whole white LED lighting. These results suggest that Se and 3500K LEDs lighting interaction is most suitable for cultivating selenium-biofortified lettuce. Acknowledgements: This project has received funding from the Research Council of Lithuania (LMTLT), agreement No. S-MIP-19-2.