Observations on the effect of molybdenum on plants with special reference to the solanaceae

In view of the similarity between certain cytological changes induced by virus disease and treatment with molybdenum, pot-and water-culture experiments were carried out to determine further the effect of this element on plant growth. Sodium molybdate was used throughout. 2 Toxic symptoms were produced with the larger dressings of molybdate, injury being shown at much lower concentrations in solanaceous species than in barley. 3 The shoots of tomato and Solanum nodiflorum turned a golden yellow, and potato tubers a reddish yellow colour when the plants were grown with the larger quantities of molybdate. 4 These colour changes were shown to be due to the presence of yellow globules of a tannin-molybdenum compound which had formed within the tissues. 5 Blue granular accumulations occurred in large numbers in molybdenum-treated plants. Their distribution was confined to tissues that contained anthocyanin pigment, and their composition was apparently of an anthocyanin-molybdenum nature.