Light/dark cycle lighting boost yield and centellosides content of vertically cultivated Centella asiatica

Centella asiatica (C. asiatica) is a representative medicinal plant rich in centellosides, which exhibit antioxidant, anti-inflammatory, and collagen synthesis-promoting activities. It is widely used as a high-value natural resource in functional cosmetics and pharmaceuticals for skin regeneration purposes. In this study, C. asiatica was cultivated in controlled environments to investigate the effects of different photoperiods (L, light) and cycle lengths (C) (L/D cycle) on yield performance and photochemical properties. The light treatments included CON (150 PPFD), C0L24 (100 PPFD), C2L8 (150 PPFD), and C4L4 (150 PPFD) per cycle, with all treatments adjusted to provide a fixed daily light integral (DLI) (8.64 mol·m⁻²·d⁻¹). C0L24 produced the highest shoot fresh weight during the first half of the 6-week growing period, whereas the shoot dry weight was highest in both C0L24 and CON. The photosynthetic rate was highest in C2L8, whereas the efficiency of plant photosystem II and electron transport rate were highest in CON, followed by C0L24. Interestingly, the maximum photochemical efficiency of photosystem II showed similar trends among the treatments, ranging between 0.8 and 0.84. Chlorophyll content was highest in C0L24, followed by C2L8. Ascorbic acid concentration was highest in C2L8 and C4L4 under a short L/D cycle, whereas centellosides concentration was highest in C4L4 and lowest in C0L24. Overall, these results indicate that continuous lighting at a fixed DLI can effectively promote shoot growth in C. asiatica in vertical farms.