Effect of nitrogen on protein content, and aminoacid composition in dry bean seeds

Abstract

Greenhouse and field experiments were conducted with bean Phaseolus vulgaris L., cv. Aroana, in order to study the effect of N on protein content of seeds. In greenhouse, the plants were cultivated in pots, with vermiculite and irrigated with nutrient solution containing 70, 210 and 630 ppm of N. In the field, N was dressed in the form of NH₄NO₃, at rates of 0, 50 and 100 kg/ha, at flowering stage. The content of protein in the seeds, at harvest, was 24.7, 27.6 and 33.7%, respectively, for levels of 70, 210 and 630 ppm. In the field, 100 kg/ha of N resulted in increases of 27.8, 20.7 and 28.1%, respectively, in the contents of total N, protein-N and nonprotein-N, when compared with check. Nitrogen dressing increased the content of lysine, cystine and leucine and reduced that of valine, threonine and methionine while phenylalanine and isoleucine contents were not affected.