Light stimulates the betaxanthin accumulation in Celosia plumosa. The induction is partially reversed by far-red and inhibited by actinomycin D, puromycin, salicylaldoxime and 2,4_dinitrophenol, while 3-(3,Cdichlorophenyl)-l,l-dimethylurea has an inhibitory effect only when photosynthesis is operative. In darkness betaxanthins synthesis is promoted by kinetin.