Dose-response curves for phytochrome-mediated anthocyanin synthesis in the mustard seedling (Sinapis alba L.)

The dose-response curves for the effect of red and green light on the synthesis of anthocyanin in mustard seedlings show a plateau. This plateau is reached with energy doses of 1 (red light) resp. 10 (green light) pW sec cm-2. A further increase in the amount of anthocyanin is induced by red or green light doses exceeding 103 pW sec cm-2. Thus the occurrence of a plateau in the dose-response curve of a phytochrome-mediated process is not restricted to the growth of the Avena mesocotyl and coleoptile.