Polar Lipid and Fatty Acid Profiles of Oat Groats Substantially Influenced by Field Management: A Comparison of Cultivars, Sowing Times and Fertilizer Composition.

The polar lipids in oat grains are crucial due to their biological functions, nutritional quality, potential use in food flavour and processing, the protection they provide against biotic and abiotic stresses, and their ability to act as cellular signalling molecules. In this study, we present novel findings about the impacts of fertilization and field management on oat polar lipid and fatty acid (FA) patterns. We evaluated the effects of two sowing-dates and fertilization combinations on the grain lipid and fatty acid composition of high-, medium- and low-oil-containing cultivars (CV): Fatima, Belinda and Symphony. Oat groats contain three major lipid classes: phospholipids, dominated by phosphatidylcholine (PC); glycolipids, with digalactosyldiacylglycerol (DGDG) being the main class of these; and sterols. A shift in the lipid profile from phospholipid to sterol biosynthesis was observed when only N was supplied compared with full fertilization, which included several macro- and micronutrients. The membrane lipid DGDG in oat grain was found to be a very unstable trait and was subjected to interactions between the genotypes and the treatments. Oats are rich in unsaturated FAs, specifically oleic acid (C18:1) and linoleic acid (C18:2). Among the three cultivars, the high-fat-containing cultivar CV Fatima had a greater oleic acid content, while the low-fat-containing CV Symphony had a greater percentage of linoleic acid, followed by Belinda. Compared with only N fertilization, full fertilization significantly increased the level of unsaturated FAs but reduced the stability of the lipids, as indicated by a lower oleic to linoleic acid ratio. Further investigation is required to address the consequences of polar lipid variability on the structural integrity of plant cell membranes, seed health and viability.