Effects of Different Lights on Pigments and Related Metabolism Enzyme Activities in Flue-cured Tobacco Leaves

In order to clarify the physiological response mechanism of plastid pigment metabolism in the maturation of flue-cured tobacco leaves under different lights, the effect of different lights on pigment metabolism was investigated on field condition by covering four color films (white, red, yellow, and blue) above tobacco plants. The results showed that the red and yellow light significantly inhibited the degradation of chlorophyll by promoting the accumulation of chlorophyll a. Red light also inhibit the degradation of caroteniods, but the blue light was opposite. At the same time, the red and yellow light reduced the chlorophyllase activity, but the blue light significantly increased it. The activity of LOX in these monochromatic treatments increased significantly in the end of leaf maturity, which could delay the senescence of tobacco leaves and cause a further degrade of pigments. These changes influence tobacco quality.