Vitamin Synthesis in Plants as Affected by Light Source.*

An inspection of the literature dealing with the subject of vitamins furnishes evidence to indicate that they are probably chemical compounds in nature, losing their potency easily through changes (oxidative, hydrolytic, or splitting in nature) whose exact nature has never been fully established. There is much to indicate that they are compounds existing in an active and an inactive form mutually interchangeable through processes not yet known. It is commonly conceded that the vitamin potency of most substances decreases with age, heat, and exposure to light, due to changes previously suggested. Articles pertaining to this subject are too commonly known and too numerous to be listed here. Vitamin C is undoubtedly most susceptible to this deterioration with vitamins A, D, and B following in order of instability. Granting that the vitamins are unstable and susceptible to some form of change as suggested, and postulating the existence of an active and inactive form, the question follows: By what methods are the compounds first activated or synthesized? It is to be deduced from the findings of others and from an inspection of data accumulated, that the actuation accompanies living processes which take place primarily in the plant, and probably is in some way dependent upon light rays; possibly it is directly related to the photosynthesis taking place and likewise dependent upon the chlorophyll content of the plants. It is generally conceded that vitamin C rapidly increases in the seed during germination. Chick and Delf (1) definitely demon-