Earlier work with buckwheat seedlings showed that dihydrokaempferol (3,5,7,4′-tetrahydroxyflavanone) (1) is a good precursor for cyanidin and quercetin. Since cell suspension cultures have several advantages for the quantitative comparison of the incorporation of a radioactive precursor into a product, the role of 1 in the biosynthesis of cyanidin was reinvestigated with cell cultures of Haplopappus gracilis. These cultures show good production of cyanidin-glycosides in blue light in a medium containing sucrose, 2,4-D and Fe-EDTA. Maximum anthocyanin production and maximal activity of phenylalanine ammonia-lyase is reached about 60 — 70 hrs. after the onset of illumination. The incorporation of 1 and of phenylalanine and 4,2′,4′,6′-tetrahydroxychalcone into cyanidin was compared under identical conditions after 1, 3 and 6 hrs. feeding time. 1 prooved to be by far the best precursor for cyanidin. The feeding time required was much shorter and the incorporation rates were much higher than in experiments with seedlings.
Anthocyanin production in suspension cultures of high-producing cells of Euphorbia millii.
