The influence of continuous far-red and white light on prenyl chain synthesis in plastids of Raphanus seedlings.

The rate of prenyl chain accumulation (C40 carotenoids; C45 in plastoquinone-9; C20 phytyl in chlorophylls, α-tocopherol and vitamin K1) in plastids of etiolated radish seedlings (Raphanus sativus L.) is determined in continuous darkness and after far-red and white light treatment. Continuous far-red light (active phytochrome P fr ) stimulates the synthesis of all prenyl chains, but has no or only little effect on the dark pattern of the prenyl chain formation. White light enhances the accumulation of prenyl chains to a much higher degree than does far-red light. By a particularly strong promotion of the accumulation of phytyl chains, which are incorporated into chlorophyll, white light changes the percentage composition of prenyl chains to that of chloroplasts.