Control of deoxyisoflavone synthesis in soybean tissue.

1. Callus tissues of Glycine max, cv. Acme, on solid or in liquid media quickly responded to cytokinins by synthesizing two compounds which appear to be glycosides of the deoxyisoflavone, daidzein. Auxin also was necessary for the effect. 2. After a lag, the response could be detected in 24 h or less by reading ultraviolet optical densities of simple acidic or ethanolic extracts of the tissues or of the liquid media and suspended tissues. 3. The effects of different levels or kinds of auxins and cytokinins were parallel to the known growth responses. 4. When 2,4-dichlorophenoxyacetic acid was used, addition of a cytokinin was not required for deoxyisoflavone synthesis. 5. Malonic acid promoted deoxyisoflavone synthesis but only in the presence of an auxin. Addition of a cytokinin was not necessary for this promotion. Citric acid also was effective but acetic, pyruvic, α-ketoglutaric, succinic, malic and fumaric acids were not. 6. The influence by cytokinins and auxins on deoxyisoflavone synthesis offers a system usable for assay of the growth substances and for study of their modes of action.