Response of Growth and Functional Components in Baby Vegetable as Affected by LEDs Source and Luminous Intensity

This study was conducted to investigate the growth characteristics and functional materials of baby vegetables as affected by different LEDs and luminous intensity at Anseongsi, Gyeonggi Province, in 2014. Test crops were beet, chicory, spinach, red leaf lettuce, crown daisy and red mustard purchased from the seed company of Dongbu Hannong and Jinheung. Growth characteristics were measured and the content of functional materials was analyzed 40 days after seeding at plug plate. Treatment of Red+Blue (4:1) at 150 micromol m-2 s-1 luminous intensity showed the highest number of leaves in five baby vegetables of beet, chicory, red leaf lettuce, crown daisy and red mustard. The highest shoot length of chicory, spinach, red leaf lettuce, crown daisy and red mustard was obtained from the treatment of Red+Blue (4:1) at 150 micromol m-2 s-1 luminous intensity. Fresh weight and dry weight of all six baby vegetables were the highest in treatment of Red+Blue (4:1) at 150 micromol m-2 s-1 luminous intensity. Content of chlorophyll a and chlorophyll b of spinach, red leaf lettuce and red mustard showed the highest in Fluorescent lamp at 150 micromol m-2 s-1 luminous intensity whereas other crops did not show definite trend under different LEDs lights and luminous intensity. The highest total content of anthocyanins and polyphenol were obtained from the treatment of Red+Blue (4:1) at 150 micromol m-2 s-1 luminous intensity in all six baby vegetables. Free radical scavenging activity was highest in all six vegetable crops at 150 micromol m-2 s-1 luminous intensity, but it was not different significantly between LEDs. As a result, the growth and the content of functional material of baby vegetables are generally to be increased in Red+Blue (4:1) at 150 micromol m-2 s-1 luminous intensity. Mixed light of Red+Blue is thought to give good effect on the growth and the content of functional material in baby vegetable crops. Because there are many differences in regard of LED lights, crop varieties, cultivation and experimental methods in their impact on the growth and functional materials of baby vegetables among researchers, it is considered that a more precise studies are needed for the crop responses to LED light and luminous intensity.