氮素对荞麦胚乳淀粉发育影响机理及其与加工品质响应机制

Buckwheat is rich in biological active ingredients, such as resistant starch and flavonoids, is the popularity health food in the 21st century. Buckwheat endosperm development and synthetic effect of buckwheat starch processing quality. Therefore, researching buckwheat growth course of endosperm starch and the accumulation of starch synthesis rule, buckwheat processing quality ascension has important practical significance. In this study，the cultivation variety of common and tartary buckwheat as the object, different nitrogen as fertilizer, using iodine, potassium iodide, TTC staining method and scanning electron microscopy (SEM), the endosperm cells develop in the process of starch accumulation characteristics and ultrastructure of the development of starch granule explore buckwheat seed endosperm starch synthesis process of AGPP, SSS, GBSS, DBE and Q enzyme activity of key enzymes in the change, revealing the key enzymes activity change rule of buckwheat starch synthesis and its response to nitrogen regulation mechanism; Study the buckwheat grain starch physical and chemical properties with different nitrogen levels, reveal the influence of nitrogen fertilizer on the mechanism of buckwheat endosperm starch development and its relationship with buckwheat starch processing quality. The results of the study will be provide theoretical basis for cultivation of buckwheat and processing and nitrogen efficient utilization.

荞麦富含黄酮、抗性淀粉等生物活性成分，是21世纪倍受青睐的健康食材。荞麦胚乳淀粉发育与合成影响荞麦加工品质。因此，研究荞麦胚乳淀粉发育进程与淀粉合成积累规律，对荞麦加工品质提升具有重要的现实意义。本项目以陕甘宁荞麦生产区甜荞和苦荞主栽品种为对象，以不同氮素含量做基肥，采用碘-碘化钾、TTC染色法及扫描电镜等手段，研究胚乳细胞发育过程中淀粉积累特点及淀粉粒超微结构，探究荞麦籽粒胚乳淀粉合成过程中AGPP、SSS、GBSS、DBE和Q酶等关键酶活性变化，揭示荞麦淀粉合成关键酶活性变化规律及其对氮素调控响应机制；研究不同氮素水平下荞麦籽粒淀粉理化性质特点，揭示氮肥对荞麦胚乳淀粉发育的影响机制及其与荞麦淀粉加工品质的关系。研究结果为荞麦优质栽培与加工利用以及氮素高效利用提供理论依据。

荞麦是集营养、食用、食疗于一体的药食兼用作物，是21世纪人们最为青睐的健康食品原料之一。荞麦虽具有营养保健功能，但产量低，且蒸煮和加工品质差，制约了荞麦的有效利用。荞麦籽粒胚乳淀粉发育与合成会大大影响荞麦加工品质。本项目以陕甘宁荞麦生产区甜荞和苦荞主栽品种为材料，设置0 kg•hm-2（N0）、90 kg•hm-2（N1）、180 kg•hm-2（N2）、270 kg•hm-2（N3）四个施氮水平，对荞麦籽粒胚乳细胞发育，淀粉积累特点，籽粒胚乳淀粉合成过程中关键酶活性变化，淀粉理化性质及其对氮素响应机制，产量及其构成因素等方面进行了研究。得出如下主要结论：（1）施氮有利于荞麦胚乳细胞长和宽的增大，有利于籽粒胚乳组织淀粉粒积累，填充速率加快，促进了籽粒粒重的增加；（2）施氮推迟了细胞核的衰亡，促进胚乳细胞分裂，增加胚乳细胞数，从而调节籽粒淀粉及其组分含量的变化；（3）四种淀粉合成关键酶ADPG-PPase、GBSS、SSS、SBE酶活性变化均呈单峰曲线变化，均在开花后15 d达到峰值，并随着施氮量的增加，淀粉合成相关合成酶活性均表现出先增加后降低的趋势；（4）在不同氮肥水平下，荞麦淀粉中直链淀粉含量有所差异，淀粉颗粒形态和亚组数量无改变，但改变了亚组比例；荞麦淀粉的晶体结构、糊化特性、热特性、溶解度、透明度等理化性质存在一定的差异；（5）随着施氮水平的增加，荞麦一级分枝数、二级分枝数、单株花簇数、单株粒数、单株粒重呈现先增加后降低的趋势，产量在施氮量为180 kg/hm2时达到最大值；（6）在黄土高原干旱半干旱地区，荞麦最佳施氮量是180-270 kg/hm2，不同品种对氮肥的响应敏感不一，要根据产地环境和品种，选择适宜的施氮量。该研究结果为荞麦品质栽培生产技术与加工品质提升具有重要的现实意义。