Photocontrol of anthocyanin formation in turnip seedlings : VIII. Wave-length dependence.

In hypocotyls the effectiveness of 703, 716 and 760 nm light was much increased if plants were transferred to red light after 6 hours. The intermediate wave-length band centred at 703 nm was ineffective when given alone but led to a high yield if followed by red light. When given before far-red light (standard far-red field), 6 hours at 703 nm reduced anthoeyanin yield in the same way as red light; when given after 6 hours of far-red, however, 703 nm light did not act like red light to sustain a high rate of anthoeyanin synthesis. It is concluded that two reactions are involved in the photocontrol of antho eyanin formation in turnip seedlings.