小麦籽粒不同部位淀粉理化特性空间分布特征及其形成的生理机理

小麦籽粒不同部位面粉品质性状存在显著差异。淀粉作为籽粒最主体的组分，是小麦加工品质最重要的决定因素之一。淀粉的加工品质主要取决于直链/支链淀粉含量及其比值（直链淀粉对品质的贡献更大）、淀粉分子的精细结构和淀粉颗粒大小分布特征。明确籽粒不同部位淀粉理化特性空间分布特征及其调控机制，可深入阐析小麦籽粒不同部位面粉品质性状差异及其调控途径。本项目拟以代表性优质专用小麦品种和一套因不同染色体组Wx基因缺失而导致的直链淀粉含量差异显著的小麦品种（系）为材料，研究小麦籽粒不同部位淀粉组分、分子精细结构、淀粉粒粒度分布等理化性状空间分布特征；并从淀粉合成底物供应、淀粉合成关键酶活性及其编码基因时空表达模式等角度，揭示小麦籽粒淀粉理化特性空间分布特征形成的生理机理；并研究氮肥运筹对籽粒淀粉理化特性空间分布特征的调控效应与调控机制，为小麦品质形成机理与调优技术途径的建立提供理论支持。

The flour quality properties largely vary with pearling layers from different positions of grain in wheat. Starch occupies the largest fraction of grain and thus one of the most important factors determining the processing quality of wheat. Processing quality of starch mostly depends on the fractions of amylose and amylopectin (amylose contributes more to starch quality), fine structure of starch molecular and parcel size of starch granules. To reveal the spatial variation in starch physiochemical properties at different positions of grain and the underling mechanisms will help further explain the spatial variation in flour quality and the regulatory approaches. In the present project, we will use representative quality wheat for specific end-use cultivars and a set of genetic materials containing eight near-isogenic lines (deletion of Wx gene in different genome) as research material. Firstly, we will study the spatial variations in synthesis of starch components, the fine structure of starch molecular, and the size distribution of starch granules from different layers of wheat. Secondly, we will try to reveal the underlining physiological mechanisms in the views of supply of starch synthesis substrates, activities of key enzymes involving in starch synthesis, and the expression patterns of the encoding genes of these enzymes. Finally, we will compare the regulatory effects of nitrogen application practices on the spatial variation patterns of starch physiochemical properties between the pearling fractions of wheat grains. The results should further elucidate the formation mechanisms of grain quality formation, and support the establishment of optimal cultivation techniques toward super quality wheat.