Composition of the Nitrogen Fraction of Apple Tracheal Sap

Abstract

Organic nitrogenous compounds accounted for most of the nitrogen present in apple tracheal sap. Aspartic acid, asparagine, and glutamine were quantitatively the most important compounds. Glutamic acid and other amino acids were also present as well as a peptide-like substance. While apple variety, rootstock, or manurial treatment may have had effects on level of nitrogen in tracheal sap they seem to have had little effect on proportions of nitrogenous compounds present. Through the growing season, however, there was a definite change in proportions of some of the constituents. The composition of the soluble· nitrogen fraction of leaves and fruits showed distinct differences from the composition of tracheal sap.