Various Light Quality including QD-LED Affect Growth and Leaf Color of Red Romaine Baby Leaf Lettuce

Abstract

Light quality has a substantial effect on crops in plant factories. Quantum dot (QD) refers to ultrafine semiconductor particles and is expressed in a variety of wavelength ranges and fine and precise colors and is attracting attention as a next-generation material. This study was conducted to investigate the effects of various light qualities, including a QD-LED light source on the growth and color development of red romaine lettuce in the LED chamber system for plant factories. The light source was red fluorescent (FL), blue (B), red (R), blue + red mixed light (BR), and blue + wide range red + red mixed light QD-LED. The growth index, chlorophyll content, and leaf color were examined. The results showed that the plant length was long without a significant difference in QD-LED and the red (R) wavelength and showed the fastest growth under QD-LED. The photosynthetic rate and chlorophyll content were the highest in QD-LED light with a broad spectrum of red light. The leaf colors a*, b*, the hue angle, and total anthocyanin content showed the highest in QD-LED light, while b* and the hue angle values were the lowest. As the light wavelength range was changed, there was a significant difference in the growth response and leaf color, and it is considered that QD-LED light should be considered positively when applied to plant factories.