Mizuna (Brassica rapa L. var. japonica) is rich in natural antioxidants such as phenolics and various healthy phytochemicals, such as glucosinolates, polyphenols and anthocyanins. It is an easy-to-obtain and research-worthy crop. Different light quality affects the physiological reactions and metabolites of plants. Greenhouse or plant factory can be used to control growth conditions to create higher value of utilization for crops. LED has the advantages of high light energy conversion rate, low output of radiant heat and low weight of light wares. In this study, two kinds of mizuna species (Green mizuna and Red mizuna) were used as the experimental materials, and hydroponic method with 9 different light treatments by different light-emitting diodes (LEDs) combinations was used to explore the effects of different light quality on the growth, antioxidant content and anti-oxidative ability. Mizuna was harvested after 30 days of planting on the hydroponic platform. Mizuna samples were ground to powder after lyophilization treatment, and then used directly or dissolved by resuspending in distilled water for all measurement. Results showed the highest fresh biomass of Green mizuna reached 25.85 g during the red light treatment. The highest content of carotenoids was obtained in the no green light treatment of Red mizuna with 2,127 μg g-1. The highest content of anthocyanin was obtained in red light treatment of Red mizuna with 110 μg g-1. The highest content of flavonoid was obtained in blue light treatment of Red mizuna with 106 μg g-1. The highest content of total phenolics was obtained is green light treatment of Green mizuna with 200 mg g-1. Red and blue light treatments were found to have negative influence of plant height and promote the accumulation of total phenolics. The best DPPH free-radical scavenging activity of 92% was found in no green light treatment of Green mizuna.
