Effect of Blue Fraction in Red–Blue LED Spectra under Constant PPFD on Antioxidant Compounds and Total Lipid Content in Basil (Ocimum basilicum L.)

Abstract

This thesis investigated the effects of different LED light regimens on physiological and quality indicators in Genovese and red basil under controlled environmental conditions. PPFD was kept constant at 200 μmol m⁻² s⁻¹, with a 16/8 photoperiod and a calculated DLI of 11.52 mol m⁻² d⁻¹, while white control light, 25% blue/75% red, and 35% blue/65% red regimens were compared. Harvesting was carried out on day 45, and growth, biomass, SLA, pigments, SPAD, TPC, TFC, and total lipid content were evaluated. The results showed that the effect of light regimen was not uniform across all parameters, and genotype played a determining role in several variables. In terms of quality indicators, TPC and TFC tended to be higher under red-weighted red-blue spectra, while red basil generally showed stronger phenolic and flavonoid responses than Genovese basil. Therefore, the study suggests that there is no single universal “best” light prescription, and quality-oriented lighting strategies should be selected according to genotype and target parameter.