SEASONAL CHANGES IN THE COMPOSITION OF THE NON-PROTEIN NITROGEN IN THE CURRENT YEAR'S SHOOTS OF BARTLETT PEAR

The material used was the non-protein nitrogen filtrate, the seasonal changes in which had been studied in a previous paper (4). This nonprotein nitrogen filtrate, obtained by extracting the samples with water and then precipitating, the proteins from the extract, was fractionated before and after hydrolysis into amide, amino, basic, humin, rest, and melanin fractions by the modified VAN SLYKE method (3). The chart on page 116 gives a schematic picture of the complete fractionation procedure.