Growth and Biochemical Responses of Green and Red Perilla Supplementally Subjected to UV-A and Deep-blue LED Lights

This study investigated the effects of UV-A and UV-A-closed visible light (deep-blue [DB]) on the growth and bioactive compound accumulation of green and red perilla. Four-week-old seedlings were cultivated in an environment control room under visible light with red, blue and white LEDs for 4 weeks and then were continuously grown under supplemental UV-A (365 nm and 385 nm) and DB (415 nm and 430 nm) lights for 7 days. UV-A and DB treatments did not enhance the growth characteristics of green perilla compared with the control; while these treatments enhanced the growth parameters of red perilla, and the values were highest in DB 415 nm. The photosynthesis rate of both cultivars showed similar trends as the growth results of each cultivar. The electron transport rate and maximum quantum yield of both cultivars were reduced under UV-A 365 nm, while these values were maintained in DB treatments. In both cultivars, total phenolic, antioxidant capacity, rosmarinic and caffeic acids and perillaldehyde levels were enhanced in DB treatments, whereas UV-A 365 nm and DB 415 nm increased the total anthocyanin content. Overall, supplemental DB 415 nm and 430 nm was suitable for improving the growth and biochemical accumulation of both perilla cultivars.