Influence of LED lamps and biostimulants on the characteristics of Brassicaceae microgreens

To evaluate the influence of light of different wavelengths and biostimulants on the yield and qualitative characteristics of radish and turnip green microgreens, two trials were conducted in an indoor environment. In the first trial conducted on radish and turnip green, three levels of light radiation were compared: red, blue, and green. In the second trial, conducted on turnip green, the effects of different light radiations on interaction with biostimulants based on moringa and borage leaf extracts were analysed in a factorial design. The results of the first trial highlighted how red light in radish increased fresh biomass. Variations in pigments did not appear to be substantial, although they were significant. The DPPH content was slightly higher for plants that benefited from blue and green radiation than for those that benefited from red radiation. The polyphenol content was lowest in the microgreen samples obtained under green light and reached the highest values under red light. In turnip greens, an increase in fresh biomass (+50.0%) was observed with red light, whereas no differences were observed due to the effect of biostimulants. The factors under study determined slight and not always significant differences in the pigments. The effects of LED and biostimulants (second trial) have mainly focused on the content of health-promoting substances. DPPH increased following treatment with green and blue light, and moringa. The polyphenol content showed significant variation owing to interactions between the factors under study. The total sugar content benefited from the use of biostimulants, particularly moringa, especially red light. Ascorbic acid content was higher under blue light. The nitrate content showed marked variation as a result of all studied factors and their interactions. Red light showed a significant reduction (43.5%) compared to the value (1.181 mg kg-1 FW) recorded with blue light. Among the biostimulants, moringa increased the nitrate content by 24.9% compared to that of the control; the increase caused by moringa was greater with green light.