Soluble Nitrogenous Constituents of Lupin Nodules

Abstract

Lupin nodules collected in two successive years were analysed for ammonia, urea, glutamine, asparagine, amino-nitrogen, peptide-nitrogen, total soluble nitrogen, and total nitrogen at fortnightly or weekly intervals from the time the plants reached full flower. The amounts of many of the constituents passed through a maximum, in the first experiment about a month after flowering, in the second at or a few days after flowering. On a sample taken a week after full flowering, assays were made of 17 individual amino-acids in three fractions representing free amino-acids, peptides, and soluble protein. Of the free amino-acids, those present in the greatest amount were aspartic and glutamic acids together with their amides, alanine, serine, histidine, and valine. The other two extracts showed a more even distribution of amino-nitrogen among the different amino-acids.