| Abstract: In order to improve the serious tipburn of lettuce in plant factory and improve the yield and quality of lettuce, the 'green lettuce' and 'Italian lettuce' in the plant factory were used as test materials to study the effects of light quality on the growth morphology, quality, photosynthetic capacity and tipburn of lettuce. The LED precise control light source was used to treat the two cultivars of lettuce with red light, blue light, green light and white light, respectively. The results showed that under blue light irradiation, the vitamin C and soluble protein content of lettuce increased compared to other light quality treatments, but the nitrate nitrogen content and rate of tipburn also increased. Under green light treatment, the rate of tipburn decreased, but the yield and various nutritional qualities were lower than other treatments. Under red light treatment, the rate of tipburn was lower, and the quality, especially the contents of soluble sugar and vitamin C improved. In industrialized cultivation of lettuce, increasing a higher proportion of red light could improve the quality of lettuce while slowing down the occurrence of tipburn. |