Nitrogen Mobilization in Pea Seedlings.

Abstract

Cotyledons, root tips, root shafts, shoot shafts and shoot tips of pea seedlings up to 5 days old, were analyzed for total N, N soluble in 70% ethanol, free amino N, amides, ammonia, urea, alcohol-soluble peptides and alcohol-insoluble peptides. From the beginning, the amount of protein in the cotyledons steadily decreases while the protein in the growing parts increases. The non-protein nitrogenous constituents in the cotyledons increase in amount during the 1st 3 days and then begin to decrease, while in the root-shoot axis these constituents increase slowly at first, and then very rapidly. Root and shoot shaft tissue is notable for relatively high concentrations of non-protein nitrogenous compounds, while root and shoot tips are very high in protein. The seedlings contain substantial amounts of peptides, but much less amide than free amino N.