This study dealt with the effect of light emitting diodes( LED),including the red light( 660 nm)( R),blue( 450 nm)( B),and a mixed red / blue / ultraviolet-B( UV-B,300 nm)( R∶ B = 4∶ 1,R∶ B = 8∶ 1 and R∶ B∶UV-B = 20∶ 5∶ 1),on growth and quality of lettuce,aiming to provide data for LED light application in protected horticulture. Compared to fluorescent lamp( CK),the red light significantly accumulationed the aboveground biomass and improved the yield,but decreased vitamin C and crude protein contents. The ...