Anthocyanin and Anthocyanin Formation in Seedlings of Fagopyrum esculentum Moench

In the foregoing lines we have tried to elucidate some points in the chaotic topic of anthocyanin formation. We, therefore, studied the processes in anthocyanin formation in different directions in one object. We choose the etiolated seedlings of Fagopyrum esculentum M o e n c h, a material readily available in every season. The disadvantages as well as the advantages of the material used are described in full in chapter I, § i and in chapter II, § 8. The chemical composition of the anthocyanin present has been partly elucidated. The same is true for the tannin, present in large quantities. We could not confirm the statement of Jonesco (1930) on the presence of leuco-anthocyanins in Buckwheat seedlings. As a matter of fact we are sure that the so-called anthocyanidin derived from the leuco-anthocyanin is a coloured product obtained from the tannin by the action of mineral acids (chapter I, § 3). The results of the chemical investigation added to microchemical observations lead to the opinion that there certainly does not exist any physiological relation between anthocyanins and tannins (chapter II, § 9). Of other substances looked upon as possible chromogens of anthocyanin pigments, we investigated the flavones. In the material used flavones could never be demonstrated (chapter I, § 4). The localisation of certain substances present in the material and studied by means of microchemical methods proved to be interesting. There seems to exist a very narrow relation between the presence of reserve food and anthocyanin formation in the hypocotyledons of Buckwheat seedlings. A narrow relation exists between development of the seedling and starch and sugars present. At the same time a similar relation exists between the presence of sugars and anthocyanin. The result is that there exist a relation between the age of the seedling and the quantity of anthocyanin to be formed (chapter II). By physiological methods we could obtain some information as to the processes involved in anthocyanin formation. Apart from the photo-chemical reaction we could prove that two oxidative processes are present during the pigment formation, the first one of which follows the photo-chemical reaction very closely, the second takes place in the dark after the exposure to light. We added more data to the knowledge obtained by studying the influence of characteristic respiratory poisons i.e. HCN and H2S. (Chapter III, IV and V). These poisons proved to have a marked influence on the formation of the anthocyanin pigment. Micro-methods to determine the quantities of hydrocyanic acid and hydrogen sulphide present in the plant material after staying in an atmosphere containing these substances were worked out (chapters IV and V). A number of oxidizing enzymes proved to be present in the material. The influence of HCN on the activity of one of these enzymes has been studied quantitatively (chapter IV). In chapter VI the literature, appeared in the last years, has been discussed and some general considerations on the reactions involved in anthocyanin formation added. We came to the following conclusions; a. a photo chemical reaction starts the chain of reactions involved in anthocyanin formation. b. favourable conditions for this photo-chemical reaction are, for instance, the presence of carbohydrates. c. the substance used in the photo chemical process has either a yellow colour or will be colourless. d. two oxidative processes are necessary. e. the reactions take place while the substances being transformed are fixed on a substrate. /. the pigment formation may involve a monomolecular reaction. g. this monomolecular reaction takes place during the loosening of the pigment from the substrate. h. ti e pigment after loosening from the substrate dissolves in the acid cell-sap.