Abstract

The light spectrum is a factor that positively influences plant growth and development and the accumulation of bioactive compounds. The objective of this study was to evaluate the effect of ambient light enrichment with different LED light spectra on the agronomic characteristics and phenolic profile of 'Levistro' baby lettuce plants grown in greenhouses. The ambient light was enriched with 12 h of blue, white, blue-red, and red light, which resulted in the following blue:green:red:far-red spectra 60:16:16:8; 28:42:22:8; 31:20:40:9 and 15:20:57:8 with a PPFD of 350 ?mol m-2 s-1. The ambient greenhouse light (26:30:30:14) was used as a control (average PPFD = 750 ?mol m-2 s-1). At harvest, 14 days after transplanting, plants grown under light enrichment showed fresh weight, dry weight percentage, leaf number and morphology similar to the control. While chlorogenic acid concentration was exacerbated under blue-red and blue light enrichment compared to the control. The quercetin concentration increased under blue-red and white light compared to the control. In view of the results, it is inferred that a PPFD half obtained in ambient light was sufficient to achieve normal growth and development of 'Levistro' lettuce plants, suggesting a more efficient use of light energy under the enrichment treatments in baby lettuce plants. On the other hand, the combined blue-red light promotes the accumulation of phenolic acids and flavonoids in the leaves of young plants. © 2025 International Society for Horticultural Science. All rights reserved.