Phytochrome control of amino acid synthesis in cotyledons of Sinapis alba

Continuous far red light, acting through phytochrome, stimulates the rate of incorporation of density label into amino acids in the cotyledons of Sinapis alba. It is shown that such stimulation leads to increased incorporation of label into proteins. This has important consequences for experiments in which rates of enzyme synthesis in light treated and dark grown plants are compared by labelling methods. The results of some such experiments are re-evaluated.