Effect of nitrogen fertilisation on protein content, total fatty acid content and composition of barley (Hordeum vulgare L.) grains

Abstract

AbstractThe impact of N‐fertilisation level on protein content, total fatty acid (TFA) content and major fatty acid composition of barley grains (cv. Eldorado), grown in a replicated field trial, was investigated. Increasing amounts of N‐fertiliser, applied at several stages during the growing season, resulted in a higher protein content and a very slightly lowered TFA content in the grains. Protein and TFA contents were negatively correlated (r=‐0.4685). Minor changes of fatty acid composition were found in the decrease of the oleic acid (C18:1) proportion (r=‐0.8376) and in the increase of the palmitic acid (C16:0) proportion (r=0.7273). The stearic acid (C18:0) and the linoleic acid (C18:2) proportions were also affected, however, no significant linear correlations with the total N‐fertiliser level were obtained. The slow increase in the linolenic acid (C18:3) proportion (r=0.5674) was too small, compared to the residual variance, to be significant. TFA content was positively (P<0.001) correlated with the oleic acid proportion, and negatively (P<0.001) with the palmitic acid proportion. These data suggest that the application of higher amounts of N‐fertiliser slightly decreases the total fatty acid content of barley grains, probably due to a decreased synthesis of oleic acid, precursor of the unsaturated C18 fatty acids. The result is a relative increase in palmitic acid.