Carotenoid Synthesis in Leaves of Etiolated Wheat Seedlings after Varying Light and Dark Treatments

A short impulse of red light has a varying effect on carotenoid synthesis in dark-grown wheat seedlings. Except for β-carotene, which remains unchanged in the dark (it increases in continuous light), the carotenoid synthesis shows the same tendency as during constant irradiation. Thus, lutein and neoxanthin slowly increases, while violaxanthin decreases. During a period of constant light following various periods of darkness after the short impulse of light, the pigment changes correspond to those occurring in the dark, but are much more pronounced. The changes are discussed on the basis of phytochrome action.