Amaranthin accumulation in continuous red and blue light by seedlings ofAmaranthus caudatus L.

Four days old Amaranthus seedlings responded to light treatment with an increase of amaranthin accumulation. With increasing irradiation time, red light caused a saturation effect. Blue light induced a high irradiation response. The blue light effect was reversible to a certain extent by far-red irradiation given at the end of the treatment with blue light. Intermittent red light (3 h red light, 3 h dark, …) caused a higher amaranthin accumulation than 24 h continuous red light. Results obtained with red and blue light are discussed on the basis of the phytochrome system.