In situ analyses of inorganic nutrient distribution in sweetcorn and maize kernels

Understanding the spatial distribution of inorganic nutrients within edible parts of plant products helps biofortification efforts to identify and focus on specific uptake pathways and storage mechanisms. Cheah et al. harvested kernels of sweetcorn (Zea mays) variety ‘High zeaxanthin 103146’ and maize inbred line ‘Thai Floury 2’ at two different maturity stages. They then examined, and the distributions of K, P, S, Ca, Zn, Fe and Mn in situ using synchrotron-based X-ray fluorescence microscopy.

The distribution of inorganic nutrients was largely similar between maize and sweetcorn, but differed markedly depending upon the maturity stage after further embryonic development. The micronutrients Zn, Fe and Mn accumulated primarily in the scutellum of the embryo during early kernel development, while trace amounts of these were found in the aleurone layer at the mature stage. Although P accumulated in the scutellum, there was no direct relationship between the concentrations of P and those of the micronutrients, compared with the linear trend between Zn and Fe concentrations.