Biological Studies on Light Quality in Environment Control

The effect of wavelength width of monochromatic light on the action spectrum of protochlorophyllide phototransformation to chlorophyllide a was examined in vivo. At the 650 nm region which has been known as the peak of action spectrum, irradiation with 2 nm half-wavelength width gave larger transformation value than that obtained with 10 nm irradiation. However, at 600 nm and 670 nm wavelength regions, very little transformation was observed.Wavelength width is shown to be significantly important in the selection of irradiated monochromatic light in the determination of action spectrum.