The study of the variation of mineral distribution and relative concentration on varieties of oat using synchrotron-based X-ray fluorescence imaging

Abstract

The objective of this study is to use synchrotron-based X-ray fluorescence imaging (XFI) and bulk analysis to investigate elements (Mn, Fe, Cu, Zn, P, S, K, Ca) distributions and relative concentrations in four cool-season oat varieties (CDC Arborg, CDC Nasser, CDC Haymaker, and Summit) obtained from the same growing location, soil conditions and harvest time at the University of Saskatchewan. XFI at the Canadian Light Source's BioXAS-Imaging beamline (5 μm resolution, 15 keV) revealed that P, K, Mn, and Zn were concentrated in the aleurone layer, scutellum, and embryo, while Ca was only localized in the aleurone layer and scutellum in the four oat varieties. Notably, S and Cu were distributed in all parts of the seed across four varieties, but the intensity was low in the endosperm. Bulk analysis results show that there were significant differences in the relative concentrations of K, Fe and Zn among four oat varieties harvested for three consecutive years (2018, 2019, 2020) at the completely mature stage. CDC Nasser oat had the lowest K and Zn, while CDC Haymaker had the highest Fe among the oat varieties. These findings highlight the impact of variety on nutritional quality and could help inform future biofortification strategies to enhance the micronutrient content for human and animal diets. This work is the first to map the oat mineral distributions across cool-season varieties using high-resolution XFI. Unlike rice, oats showed minimal mineral accumulation in the hull, ensuring nutritional retention post-milling. Overall, this study shows XFI's potential as a non-destructive tool for cereal grain analysis and supports breeding nutrient-dense oat varieties to address global micronutrient deficiencies.