Phosphorus application alters concentrations and proportions of organic Se forms in the grain of winter wheat

Abstract

AbstractA deficiency or excess of selenium (Se) can cause disease in the human body, and the dietary intake of organic forms of Se is considered the preferable way to satisfy the Se demand in humans. P application decreases Se uptake and thus also Se concentrations in grains of crops, but little is known about how the P application level may affect the organic forms of Se in the grain of winter wheat. A pot trial with three P levels (0, 80, and 160 mg P kg−1 soil) and three Se levels (0, 0.5, and 1 mg Se kg−1 soil) was conducted to investigate the effect of P application on inorganic and organic Se forms, Se bound to protein, polysaccharide, and nucleic acid as well as Se in different protein fractions in the grain of winter wheat. Overall, the concentrations of total Se, and of Se in all analyzed forms, increased with increasing Se application regardless of the rate of P application. In the absence of Se, P application did not have a significant effect on the concentrations of any of the measured Se forms. However, in the presence of Se, increasing P application significantly decreased the concentration of Se of each form. The different rates of P and Se application influenced the proportion of each form of Se in different ways. Increasing levels of P application decreased the concentration of each form of Se in the grain of winter wheat, most likely by a combination of a dilution effect due to enhanced grain yield, and an inhibited Se uptake. Despite an overall decrease in grain Se‐protein, P application might improve the quality of wheat flour by enhancing the accumulation of Se in organic forms such as Se‐nucleic acids and Se‐polysaccharides, as well as the Se in the gliadin and glutenin fractions in the grain.