[Phytochrome system and synthesis of lipoquinones in the plastids of etiolated hordeum seedlings].

Short pulses of red light induce in etiolated barley seedlings an enhanced synthesis of plastidic benzoquinones and vitamin K1, which can be reverted by subsequent irradiation with short pulses of far-red. As compared to the dark there is more formation of plastoquinone-9 than alpha-tocopherol. The enhanced formation of vitamin K1 is coupled with a concomitant decrease in the level of the second naphthoquinone vitamin "K". The data show that active phytochrome Pfr, also in its ground state, induces the light triggered lipoquinone synthesis which is connected to thylakoid formation. The red light induction of enhanced plastoquinone-9 synthesis cannot be fully reverted by subsequent far-red and seems to be a very fast phytochrome response.