Comparison of the Growth Efficiency and Bioactive Compounds of Achyranthes japonica Nakai according to the Sowing Amount in Vertical Farms

Abstract

Achyranthes japonica Nakai (AJN) is grown mainly in the warm regions of South Korea. It is a high -value medicinal plant with various pharmacological effects, including joint protection, obesity prevention, and diabetes prevention. AJN is a plant mainly valued for its roots, and it takes approximately two years from sowing before the roots can be harvested. Therefore, this study sought to develop better AJN cultivation technology in a microgreen form in a vertical farm and to confirm the bioactive compounds and antioxidant capacity according to the sowing amount. After soaking the seeds for three days, they were sown in a growing tray with drain holes (31.5 x 23 x 7.5 cm, L x W x H) filled with a commercial ginseng soil mix medium and subjected to experimentation. AJN seedlings which had been germinated in the dark for four days were grown in a vertical farm. The treatment groups were tested at 0.5, 1.0 and 2.0 g. As the sowing amount was increased, the fresh and dry weights increased. Meanwhile, the fresh weight relative to the sowing amount showed the greatest efficiency at 0.5 and 1.0 g. Depending on the sowing amount the phenol content was highest at 0.5 g, and the flavonoid content was highest at 0.5 and 1.0 g. Based on previous results, it was appropriate to sow at 1.0 g or less considering growth for economic feasibility; therefore, sowing at 14 g or less per m 2 was determined to be appropriate here. It was confirmed that 20-hydroxyecdysone, the main secondary metabolite of mature AJN, was also present in microgreen AJN; 20E in microgreen AJN grown in the vertical farm was higher than the level in mature leaves and stems grown in the open field, but the level in mature roots was approximately 2.1 times higher than in the microgreens. These results show that microgreen AJN is a valuable plant material.