Abstract
The global demand for medicinal plants is increasing. The quality of plants grown outdoors, however, is difficult to control. Myriad environmental factors influence plant growth and directly impact biosynthetic pathways, thus affecting the secondary metabolism of bioactive compounds. Plant factories use artificial lighting to increase the quality of medicinal plants and stabilize production. Photosynthetic photon flux density (PPFD) and electrical conductivity (EC) of nutrient solutions are two important factors that substantially influence perilla (Perilla frutescens, Labiatae) plant growth and quality. To identify suitable levels of PPFD and EC for perilla plants grown in a plant factory, the growth, photosynthesis, and accumulation of secondary metabolites in red and green perilla plants were measured at PPFD values of 100, 200, and 300 μmol m-2 s-1 in nutrient solutions with EC values of 1.0, 2.0, and 3.0 dS m-1. The results showed significant interactive effects between PPFD and EC for both the fresh and dry weights of green perilla, but not for red perilla. The fresh and dry weights of shoots and leafy areas were affected more by EC than by PPFD in green perilla, whereas they were affected more by PPFD than by EC in red perilla. Leaf net photosynthetic rates were increased as PPFD increased in both perilla varieties, regardless of EC. The perillaldehyde concentration (mg g-1) in red perilla was unaffected by the treatments, but accumulation in plants (mg per plant) was significantly enhanced as the weight of dry leaves increased. Perillaldehyde concentrations in green perilla showed significant differences between combinations of the highest PPFD with the highest EC and the lowest PPFD with the lowest EC. Rosmarinic acid concentration (mg g-1) was increased in a combination of low EC and high PPFD conditions. Optimal cultivation conditions of red and green perilla in plant factory will be discussed in terms of plant growth and contents of medicinal ingredients.
Highlights
The global demand for medicinal plants such as perilla is increasing (Uniyal et al, 2000; Schippmann et al, 2002; Bodeker and Burford, 2007; Payyappallimana, 2010)
The growth parameters of green and red perilla were promoted under higher Photosynthetic photon flux density (PPFD) values when higher electrical conductivity (EC) values were applied (Figures 1, 2)
The sensitivities to PPFD and EC changed with variety; green perilla growth tended to be more sensitive to EC than to PPFD, whereas red perilla growth tended to be more sensitive to PPFD than to EC
Summary
The global demand for medicinal plants such as perilla is increasing (Uniyal et al, 2000; Schippmann et al, 2002; Bodeker and Burford, 2007; Payyappallimana, 2010). Secondary metabolites in perilla plants, such as perillaldehyde and rosmarinic acid, reportedly have the potential to prevent disease, due to their anti-allergic, anti-inflammatory, and antidepressant effects (Makino et al, 2003; Sanbongi et al, 2004; Zhang et al, 2008; Ito et al, 2011; Igarashi and Miyazaki, 2013). As the unique flavor of perilla originates from perillaldehyde and other monoterpenes, the concentration of perillaldehyde in perilla leaves is important as a food-flavoring culinary herb. Rosmarinic acid is commonly found in Labiatae family plants and possesses various phenolic bioactivities that include anti-Alzheimer’s disease, antiviral, antibacterial, anti-inflammatory, and antioxidant qualities (Petersen and Simmonds, 2003; Hamaguchi et al, 2009; Ono et al, 2012). The concentrations of perillaldehyde and rosmarinic acid in perilla are important for their culinary and clinical applications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
