Light Intensity during Green-Leaf Butterhead Lettuce Propagation Influences Yield and Carotenoids at Harvest

Controlled environment agriculture (CEA) operations must increase resource-use efficiency, yield, and phytonutrient concentrations to remain competitive. Carotenoids are phytonutrients of interest due their purported health promoting effects. Their content is impacted by environmental controls, including lighting. Light-use efficiency increases with greater planting density, which highest during seedling production. This creates the opportunity raise light intensity production improve growth characteristics at harvest. Therefore, objective this research was quantify extent influences carotenoid accumulation in green butterhead lettuce seedlings, if differences Lettuce ‘Rex’ (Lactuca sativa L.) seedlings were grown under fluorescent lighting intensities 60, 100, 200, 400, or 600 µmol·m−2·s−1 a 24-h photoperiod. After 14 days, transplanted into raft hydroponic systems common greenhouse for 21 days. At transplant final harvest, tissue samples collected stored −80 °C analysis. Carotenoids, β-carotene, lutein, neoxanthin, zeaxanthin, violaxanthin, chlorophylls b quantified using high-performance liquid chromatography (HPLC). We observed 475% fresh mass enhancement 400 versus 60 µmol·m−2·s−1, 174% improvement persisting Higher also generally increased leaf numbers as well concentrations. Final harvest decreased increasing intensity. Thus, producers should be cognizant that strongly finished morphology, content.