A recent study explores innovative cultivation strategies for Achyranthes japonica Nakai (AJN), a medicinal plant beneficial for joints, focusing on reducing its lengthy production period from sowing to harvest, which traditionally takes two years in open fields. Utilizing a vertical farming system with commercial ginseng soil and controlled conditions—temperature at 23 ± 2 °C, humidity at 50 ± 10%, and light intensity at 170 ± 15 µmol·m−2·s−1—researchers produced high-quality AJN microgreens. The study particularly investigated the effects of pre-harvest UV-B exposure (1.0 ± 0.3 W/m−2) on AJN's growth and secondary metabolites, notably 20-hydroxyecdysone (20E), a key indicator of AJN's quality. Different UV-B treatment schedules were tested, including continuous, intermittent, and recovery periods, to determine their impact on AJN's phenols, flavonoids, antioxidant capacity, and 20E levels. Findings revealed that short-term UV-B treatment before harvesting, especially intermittent 6-hour exposure followed by a 6-hour recovery, significantly increased the levels of secondary metabolites and 20E by about 1.4 times compared to the control, without negatively affecting the plant's biomass. This study suggests that tailored UV-B exposure strategies enhance the nutritional and health-promoting properties of AJN microgreens, offering a viable method for improving their production in vertical farming systems.
Ye Lin Kim, Moon-Sun Yeom, Han-Sol Sim, Ga Oun Lee. Effect of Pre-Harvest Intermittent UV-B Exposure on Growth and Secondary Metabolites in Achyranthes japonica Nakai Microgreens in a Vertical Farm.
DOI:10.3390/horticulturae10101040
Source: Research Gate.