The Movement of Organic Nitrogen Compounds in Plants: With two Figures in the Text

Abstract

The hypothesis that the movement of organic nitrogen, like that of carbohydrate, is governed by the prevailing concentration gradients for the mobile compounds in the phloem has been tested by determining the effect on nitrogen distribution when normal translocation was interrupted by ringing in Pelargonium spp. and Vicia faba plants. Nitrogen compounds in the plant tissue were fractionated into protein, soluble protein, amide, amino-acid, peptide, nitrate, and ammonia nitrogen. The presence of short-chain peptides in the extracts was confirmed by paper chromatography. Results showed that accumulation above the ringed zone was confined to the soluble nitrogen fractions and that amino-acids and possibly peptides were involved in translocation. The direction of movement may be determined by the prevailing concentration gradients of these compounds in the phloem tissue.