Substitution of green light for partial red light promoting the yield, Se accumulation and organic Se formation of radish and pea microgreens in species-dependent manner under red-blue LEDs

Selenium (Se) biofortification in microgreens is a promising strategy to address human Se deficiency, yet the regulation of Se metabolism by specific light qualities, such as green light, remains unclear. In this study, an investigation was conducted under a controlled environment into the effects of three red-blue lights and two red-blue-green lights on yield, Se accumulation, transformation, and metabolism of radish and pea microgreens. The results showed that high red-to-blue ratios and green light supplementation significantly increased plant height, fresh weight, total and organic Se contents, and total Se translocation factors in both microgreens. Notably, increasing the red-blue light ratio and introducing green light significantly increased SeCys and Se(IV) contents in pea microgreens, while improving SeCys, SeMet, and Se(VI) levels in radish microgreens. Furthermore, high-ratio red-blue light significantly elevated GSH and ATPS levels in radish microgreens, whereas red-blue-green light improved CS and SMT levels in both microgreens. In conclusion, high-ratio red-blue light, with or without green light, increased the expression of Se-metabolizing enzymes in microgreens, enabling high yields and promoting total and organic Se accumulation. Moreover, radish microgreens accumulated high levels of total and organic Se in more Se species than pea microgreens. Therefore, increasing the red light ratio or introducing green light is recommended to improve the yield and enhance organic Se conversion during the cultivation of Se-enriched vegetables.