Enhancement of Crepidiastrum denticulatum Production Using Supplemental Far-red Radiation under Various White LED Lights

This is the authors' abstract. We don't add key points for this paper.

The electric energy consumption of artificial lighting sources is a major factor to increase the production cost in plant factories with artificial lighting (PFALs).Therefore, improving the light use efficiency of lighting sources is an important task in securing the economic feasibility of PFALs.The purpose of this study was to compare the productivity of Crepidiastrum denticulatum (Houtt.)Pak & Kawano and the light use efficiency of various white LEDs with or without far-red light.Three-week-old seedlings were transplanted in wick culture systems and grown under 20.9 ± 0.1°C air temperature, 60.8 ± 0.1% relative humidity, 938.2 ± 5.8 µmol•mol -1 CO2 concentration, 250.6 ± 0.6 µmol•m -2 •s -1 PPFD, and 16 h light period in PFAL.Light treatments used were as followed; 3 types of commercial white LEDs (CL 1, CL 2, CL 3) as controls, white LEDs [Warm W (WW), Neutral W (NW), Neutral W+Red LEDs (NWR), Cool W (CW)], and white LEDs with far-red LEDs (WWFR, NWFR, NWRFR, CWFR).Supplemental far-red radiation to white LEDs increased the shoot growth characteristics (shoot fresh weight, leaf length, and leaf area), and the shoot growth of plants in WWFR was the highest.On the other hand, supplemental far-red light decreased the chlorophyll index and did not affect the flavonoid index.Total electric power consumption was the lowest in CL 1 and was the highest in WWFR.The light use efficiency of WW and WWFR was high, and supplemental far-red light to white LEDs increased the light use efficiency by 3-15%.Therefore, supplemental far-red radiation to various white LEDs could reduce the plant production cost by improving the productivity and the light use efficiency of crops in PFALs.