Abstract
Establishment of an effective supplementary lighting procedure was necessary to improve the quality of hydroponically grown red-leaf lettuce without increasing the production cost. The effect of light quality in supplementary lighting on the flavonoids (anthocyanins and flavonols) concentration and the expression of those biosynthesis related genes was investigated in leaves of the lettuce. Flavonols concentration increased in the immature leaves than those grown under the other light source, such as sole UV-B, blue and red. Grown under the simultaneous light with UV-B and blue. At this time, one of the key enzymes, flavonol synthase (FLS) expression in the immature leaves was almost coordinately regulated with the level of flavonols. It is notable that FLS expression in the immature was especially increased under the UV-B and blue simultaneous lighting with the immature leaves. The Inoue Enryo Memorial Foundation for Promoting Sciences supports a part of this work at 2006 fiscal year.
