Accumulation characteristics and structural properties of starch in different spatial positions of wheat endosperm under nitrogen application

Starch accumulation in wheat endosperm has spatial differences. In this study, the accumulation, granule size distribution, physicochemical properties of starch in different spatial positions in wheat endosperm and response to nitrogen treatment were analysed. Results indicated that the starch content in the inner endosperm was higher than that in the outer endosperm. The total starch and amylose contents in the inner and outer endosperms decreased and increased after nitrogen treatment, respectively. The starch granules that accumulated in the inner endosperm were larger than those in the outer endosperm 10 days after anthesis. The amount of C-type starch granules in the inner endosperm was less than that in the outer endosperm, and nitrogen treatment increased the C-type starch granules in the inner endosperm. After nitrogen treatment, the short chains decreased, whereas the middle and long chains increased in the inner and outer endosperms. Nitrogen treatment also increased the crystal area in the inner and outer endosperms, especially the single helix in the inner endosperm. These conclusions provide new insights into the mechanism of starch accumulation in wheat endosperm and its response to the external environment.