Starch granule size distribution in wheat grain in relation to phosphorus fertilization

Abstract

SUMMARYStarch granule size distribution of wheat is an important characteristic that can affect its chemical composition and functionality. Phosphorus (P) fertilization has been studied extensively; however, little is known about its impact on starch granule size distribution in wheat. In the present study, two high-yield winter wheat cultivars were grown under different P fertilization conditions to evaluate its effect on starch granule size distribution and starch components in wheat grains at maturity. P fertilization resulted in a significant increase in the proportions (both by volume and by surface area) of B-type (<9·9 μm equivalent diameter (e.d.)) starch granules, with a reduction in those of A-type (>9·9 μm e.d.) starch granules. The P fertilization also increased starch content, amylose content and amylopectin content at maturity. However, P fertilization conditions significantly reduced the ratio of amylose to amylopectin, which showed a significant positive relationship with the volume proportion of granules 22·8–42·8 μm e.d. but was negatively related to the volume proportion of granules 2·8–9·9 μm e.d.