Effect of hydroponic nutrient composition and the barley variety on saponarin production under white LED

Abstract This study investigates the effect of nutrient composition and barley cultivars on saponarin production in young barley leaves (YBL) under low-intensity white LED light. Various treatments involving K 2 HPO 4 , NaCl, and salicylic acid (SA) were evaluated to be under 6500 K light with 210 PPFD. Among different nutrient combinations, 600 mg L -1 K 2 HPO 4 with 0.1% NaCl significantly enhanced saponarin concentration (12.3 g kg dw -1 ) and total saponarin amount per plant (150 µg plant -1 ). In addition, the effects of light intensity on saponarin production were also examined across six barley cultivars, and the high light intensity (500 PPFD) notably increased total saponarin amount (212 µg plant -1 ) in Keunal-bori than Hyenuri cultivars. Otherwise, Hyenuri cultivar showed the highest total saponarin amount (114 µg plant -1 ) at low light intensity (100 PPFD), as well as the highest electricity efficiency (201 mg kWh -1 ). These findings provide valuable insights into optimizing cultivation conditions for each cultivar in plant factories to maximize saponarin production while balancing energy consumption and metabolic efficiency.