Starch Granule Size Distribution and Pasting Characteristic Response to Post-Anthesis Combined Stress of Waterlogging and Shading

Huawei Li,Fahong Wang,Dong Jiang,Bin Zhang,Zongshuai Wang,Qicui Zhuo

doi:10.3390/agriculture10090384

Abstract

The combined stress of waterlogging and shading (WS) caused by continuous rain threatens the production of high-quality weak gluten wheat in China (Triticum aestivum L.). To evaluate its influences on wheat quality formation, Yangmai 158 was chosen to be subjected to WS at 0–7 days after anthesis (DAA, WS0–7), 8–15 DAA (WS8–15), 16–23 DAA (WS16–23), and 24–31 DAA (WS24–31), respectively, with non-stressed plants as control (Non-WS). Compared with Non-WS, WS reduced the amylopectin content and enhanced amylose content in the mature grains. WS enhanced the number and surface but reduced the size of the starch granules. The number, volume, and surface area percentages of B-type starch granules were enhanced, and the number and volume percentages of A-type starch granules were reduced by WS. The peak viscosity and gelatinization temperature were enhanced and the low viscosity and final viscosity were decreased by WS. WS applied at the mid-grain-filling stage (WS8–15 and WS16–23) had greater modification on the starch content, granule size distribution and pasting characteristics than that applied at early (WS0–7) or late (WS24–31). The changes of starch pasting characteristics under WS had a significant correlation with the amylase and amylopectin content, amylase/amylopectin, and the ratio of the volume percent of B-type and A-type starch granules.

Highlights

Starch is the most abundant component in winter wheat grains, and accounts for two-thirds to three-quarters of wheat kernel dry weight
The amylose content in grains increased under waterlogging and shading stress (WS) treatments; the biggest increment was found in WS8–15, followed by WS16–23 and WS0–7, and was WS24–31, significant differences existed among all of the treatments except between WS0–7 and WS16-23
The total starch content of wheat grains decreased by 12.3% and 4.5% (p < 0.05) under

Summary

Introduction

Starch is the most abundant component in winter wheat grains, and accounts for two-thirds to three-quarters of wheat kernel dry weight. At least two distinct starch granules, according to their size, exist in the grains of mature wheat, the large A-type with a boundary diameter bigger than 10 μm and the small B type with a boundary smaller than 10 μm [5,6,7]. A-type granules constitute the majority weight of starch [1,8], whereas B-type granules comprise up to 99% of granules in number [9]. Starch granules are primarily composed of amylose and amylopectin bound with a few proteins and lipids [2,6,10,11]. Amylose is a predominantly linear molecule linked by α-1,4 bonds that comprises 25–30% of wheat grain starch. Amylopectin is a Agriculture 2020, 10, 384; doi:10.3390/agriculture10090384 www.mdpi.com/journal/agriculture

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Conclusion