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

Su Jung Han,Ju Young Kim,Ho-Min Kang,Young-Tack Lee,Yongduk Kim,Lixia Wang,Ki-Young Choi,Mohammad Z Islam,Joo H Lee,In-Lee Choi

doi:10.15835/nbha47311580

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.  ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Highlights

The recent increase in the demand for convenient and healthy foods resulted in consumer interests in baby leaf vegetables, which are ready-to-eat (Santos et al, 2014)
When lettuce was cultivated in various lights using a light emitting diode (LED), blue light influenced the growth of lettuce (Johkan et al, 2010), and the anthocyanin content of red leaf lettuce was affected, depending on the wavelength of the LED lights (Lee et al, 2010)
This study aimed to find the practical use of Quantum dot (QD)-LED light sources in plant factories using artificial light sources and basic data on producing high quality leafy vegetables by comparing the growth and quality of red romaine baby leaf lettuce under different light sources, which include QD-LED light sources

Summary

Introduction

The recent increase in the demand for convenient and healthy foods resulted in consumer interests in baby leaf vegetables, which are ready-to-eat (Santos et al, 2014). Baby leaf vegetables that have been in demand in recent years include lettuce, spinach, rocket, lamb’s lettuce and Swiss chard (Fallove et al, 2009). Lettuce has been used for research related to the light quality using artificial light sources in a closed plant factory environment due to the low light saturation point (Cha et al, 2013). The light quality of the artificial light in a closed plant factory has an important role on the quality and growth of crops (Lin et al, 2013). When lettuce was cultivated in various lights using a light emitting diode (LED), blue light influenced the growth of lettuce (Johkan et al, 2010), and the anthocyanin content of red leaf lettuce was affected, depending on the wavelength of the LED lights (Lee et al, 2010)

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