Effects of Drought Stress on Wheat Endosperm Starch Structure and Physicochemical Properties of Different Varieties
SONG XiaoJun;ZHANG Min;WU XuePing;ZHAO Cheng;SHI Jian;ZHANG YuChun;LIU XiWei;CAI RuiGuo;Life Science and Technology Institute, Hebei Normal University of Science & Technology;Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences/National Engineering Laboratory for Improving Quality of Arable Land;
【Objective】The objective of this experiment is to study the effects of drought stress on the composition, granule size distribution, pasting properties and crystal properties of wheat endosperm of different varieties, and reveal the intrinsic relationship between the structure and physicochemical properties of wheat starch. 【 Method 】 The wheat cultivars Jingdong8(JD8), Henong825(HN825), Jimai585(JM585) and Nongda211(ND211) were used as the test materials, and irrigated and rainfed treatments were designed in research of the effects of drought stress on wheat endosperm starch structure and physicochemical properties. 【Result】Drought stress significantly inhibited the accumulation of starch in wheat endosperm, but it had no significant effect on the Am/Ap ratio of wheat starch. The granule volume, surface area and number distribution of wheat endosperm showed a bimodal curve. The effect of drought stress on starch grain size distribution of wheat endosperm was different due to the difference of genotype and grain size, in which it had a great influence on the surface area and the number distribution of starch granule size 5 μm. Drought stress didn't change the crystal type of wheat endosperm starch, but significantly increased the crystallinity of starch, and the effects of drought stress on intensity of X-ray diffraction peak were different due to different cultivars and diffraction angles. Drought stress significantly increased trough viscosity and pasting temperature of starch, prolonged the pasting time, while significantly reduced the peak viscosity and breakdown, and there was a genotypic difference in final viscosity and setback. Correlation analysis showed a that the wheat endosperm starch crystallinity showed significant negative correlation with total starch and Am content, and a significant positive correlation with Ap content. The total starch content showed a significant positive correlation with peak viscosity. The Am content showed a significant positive correlation with peak viscosity and breakdown, and a negative correlation with the pasting temperature. The correlation between the Ap content and pasting parameters was not significant, while the Am/Ap ratio of wheat starch showed a significant negative correlation with the pasting time. The volume of 5 μm and 10 μm starch granule, respectively, showed a significant and an extreme significant negative correlation with final viscosity and setback, but the starch granule with diameter 15 μm was positively correlated with final viscosity and setback. The correlation between granule volume distribution and crystallinity of wheat was not significant. Wheat starch peak viscosity and breakdown, respectively, showed an extremely significant and significant negative correlation with crystallinity, but there was a significant positive correlation between the pasting temperature and crystallinity. 【Conclusion】Drought stress changed the wheat endosperm starch composition, granule size distribution, crystallinity and pasting parameters. There were significant correlations between wheat endosperm starch structure and physicochemical properties, indicating that the effects of drought stress on the structure of wheat starch, indirectly affected the physicochemical properties, therefore, the cultivation conditions could be adjusted to achieve the purpose of quality wheat production.
【Fund】： 国家自然科学基金(31201157);; 河北省自然科学基金(C2015407061);; 河北省教育厅优秀青年基金(Y2012032);; 国家科技支撑计划(2015BAD22B03);; 国家重点研发计划(2016YFD300804)
【CateGory Index】： S512.1
【CateGory Index】： S512.1