【作者】 盛婧；

【导师】 郭文善；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2004， 博士

【摘要】 通过2001-2003年试验，研究了不同类型专用小麦籽粒直、支链淀粉含量、比例及累积动态，观察了小麦籽粒淀粉粒形成过程，分析了籽粒中与淀粉合成有关的酶的活性及不同器官糖含量与淀粉形成的关系，探讨了淀粉、蛋白质对加工品质的影响以及栽培措施和激素处理对淀粉、品质的调节效应，以期为专用小麦品质改良提供理论依据。试验主要结果如下： 1．对不同类型专用小麦品种籽粒淀粉积累动态研究结果表明，不同类型专用小麦籽粒中总淀粉、直链淀粉、支链淀粉含量随籽粒灌浆充实而不断上升，其含量增加速率呈“慢-快-慢”的趋势，直链淀粉含量增加速率在花后25-30天达到最大，总淀粉、支链淀粉含量增加速率高峰则出现在花后15-20天；籽粒中总淀粉、直链淀粉、支链淀粉积累量变化均呈“S”型曲线，直链淀粉积累速率在花后25-30天达到峰值，支链淀粉、总淀粉积累速率在花后20-25天达到峰值。直／支比随籽粒灌浆历程的推移呈“V”型曲线变化。弱筋小麦籽粒淀粉含量高于中强筋小麦。不同粒位籽粒淀粉质量也存在差异。4粒小穗中4位粒的淀粉含量和粘度参数最高，但其粒重最小、淀粉积累量最低。 2．通过对不同类型专用小麦籽粒淀粉粒形态结构的观察，结果表明不同类型专用小麦品种籽粒胚乳中淀粉粒的生长过程基本一致。花后7天籽粒胚乳细胞内扬州大学博士学位论文均开始出现少量I型淀粉粒;花后9天I型淀粉粒上开始出现乳头状突起，之后突起从I型淀粉粒上剥离，形成n型淀粉粒;花后21天n型淀粉粒剥离速度加快，数目剧增。花后25天I型淀粉粒上乳头状突起分化基本停止，之后I、n型淀粉粒继续充实。花后25天弱筋小麦胚乳中n型淀粉粒数量显著多于强筋小麦，此差异一直保持至籽粒成熟。同一籽粒腹部11型淀粉粒多于背部。施氮量和氮肥运筹比例对I、n型淀粉粒大小比例有着显著的调节效应。当施氮量增加或氮肥后移，籽粒中n型淀粉粒体积扩增明显。 3.以三个类型专用小麦品种为材料，研究植株可溶性总糖、蔗糖含量及籽粒中淀粉合成关键酶活性的动态变化，分析关键酶活性与淀粉形成的关系，结果表明，不同类型专用小麦花后剑叶中SPS活性变化呈下降趋势，蔗糖合成相应减少;籽粒中蔗糖含量在开花10天后亦呈下降趋势，55活性同步下降;茎鞘中可溶性总糖和蔗糖含量花后巧天达到最大值，基部节间、中部节间可溶性总糖和蔗糖含量高于穗下节间。剑叶、茎鞘、籽粒中可溶性总糖、蔗糖含量与淀粉含量呈显著正相关。籽粒中AGPP、555、GBSS、SBE活性均呈单峰曲线变化，AGPP、555、SBE活性均在花后25天达到峰值，而GBSS则在花后30天出现峰值。支链淀粉、总淀粉积累速率与籽粒中总的AGPP、555、GBSS、SBE活性呈极显著正相关，直链淀粉积累速率与籽粒中总的AGPP、GBSS、 SBE活性呈极显著正相关。淀粉含量与单位籽粒重量的AG卫P、555、GBSS、SBE活性成正比。三个类型品种以弱筋小麦扬麦9号单位重量的AGPP、555、GBSS、SBE活性最高，因而其最终淀粉含量也最高;而强筋小麦烟2801单位重量的AGPP、555、GBSS、SBE活性最低、其淀粉含量也最低。 4.以江苏省具有代表性的三个专用小麦品种为材料，分析籽粒淀粉、蛋白质和加工品质关系，结果表明:淀粉含量与降落值、湿面筋含量、沉降值、面团形成时间、稳定时间等加工品质指标呈显著负相关。面粉粘度参数与大多数加工品质指标也呈显著负相关。面粉粘度特性7个参数中，以峰值粘度和糊化温度变异度最大。不同类型专用小麦对籽粒品质指标要求不同，就强、中筋小麦而言，要求较高的湿面筋含量和较长的面团形成时间、稳定时间，因此不宜追求过高的淀燮鱼工回娄型专用小麦籽粒淀粉形成及其与加工品质的关系粉含量;而弱筋小麦要求较低的湿面筋含量和较短的面团形成时间、稳定时间，因此应提高淀粉含量。蛋白质含量与降落值、湿面筋含量、沉降值、面团形成时间、稳定时间等加工品质指标呈极显著正相关，因此强、中筋小麦应以提高蛋白质含量为目标，而弱筋小麦蛋白质含量则不宜过高。就蛋白质组分而言，醇溶蛋白与各加工品质性状的相关系数均为最大，谷蛋白和清蛋白其次，球蛋白最小。通径分析表明，蛋白质对各籽粒加工品质指标的影响作用大于淀粉。 5.本试验认为总淀粉、直链淀粉含量可以作为专用小麦的品质指标来考虑。优质专用小麦籽粒总淀粉、直链淀粉含量应具备以下条件:一等优质强筋小麦籽粒总淀粉含量应蕊68.8%，直链淀粉含量毛13.5%;二等优质强筋小麦籽粒总淀粉含量应蕊71.1%，直链淀粉含量延14.5%;优质弱筋小麦籽粒总淀粉含量应)78.5%，直链淀粉含量妻17.3%;中筋小麦介于两者之间。 6.研究不同栽培措施对专用小麦籽粒淀粉质量和加工品质的调节效应，结果表明，播期、密度、氮肥、磷肥等栽培措施对不同类型专用小麦籽粒淀粉组分含量、粘度特性和加工品质都具有显著的影响。在适宜播期范围内迟播有利于提高强筋小麦籽粒蛋白质、湿面筋含量，延长面团形成时间、稳定时间，降低淀粉含量及面粉各粘度参数;播期过迟面团形成时间、稳定时间反而下降。密度对品质的影响因品种而有差异。相同施更多还原

【Abstract】 The experiments mainly studied the dynamic of starch content, observed the development of starch granules in grains of wheat for different end uses, analyzed the relationship of key enzymes involving in starch synthesis and sucrose content with starch content, discussed the relationship of starch and protein with processing quality and investigated the effects of cultivating measures on grain starch. The main results were as follows.1. Dynamics of grain starch accumulation in wheat varieties for different end uses were s tudied. T he results s bowed t hat a mylose, amylopectin a nd s tarch c ontents i n grains rose gradually after anthesis. The content increasing rate and accumulating rate of amylose appeared their maximum on the 25-30th day after anthesis (DAA) .While amylopectin content increasing rate and accumulating rate appeared on the 15-20th DAA and 20-25th DAA respectively. The ratio of amylose to amylopectin showed "V" type curve change. Starch content in weak-gluten wheat grains was higher than that in medium-gluten and strong-gluten wheat grains. Grain starch content and quality at different grain positions of the same variety were different. Grain starch and pasting parameters quality at the fourth position was the highest in a spikelet with four gains, but its weight was the lowest, so starch accumulation amount was the lowest.2. Starch granule structure was studied in grain endosperm cells both of weak-gluten wheat Ningmai 9, Yangmai 9 and strong-gluten wheat Zhongyou 9507, Yan 2801 from 2001-2003. The development of starch granules in grain endosperm of two types above was basically the same. Only did a few starch granules appear in endosperm cells on the 7th DAA. Mastoid protuberances started to appear on the surface of type I starch granules on the 9th DAA. Later mastoid protuberances seperated from type I starch granules and developed into typeIIstarch granules. The number of type II starch granules increased rapidly on the 21st DAA. Mastoid protuberance differentiation generally stopped after the 25th DAA, and type I and II starch granules continued to fill till grain mature. At the same position, the number of type II starch granules in weak-gluten-wheat grains was more than that in strong-gluten wheat grains from the 25th DAA to maturity.The number of type II starch granules in the abdomen was more than that in the dorsum in the same grain at maturity. N application amount and the ratio of basal to top dressing N had significant effects on size and number of type I and II starch granules. The treatment with greater N application amount or higher percentage of top dressing N had larger type II starch granules in grains.3. Changes of soluble sugar and sucrose contents in wheat plant and the activities of key enzymes i nvolving in starch biosynthesis in g rains were s tudied. The r esults showed that SPS activity in flag leaves declined after anthesis, and sucrose content in flag leaves decreased correspondingly. Sucrose content and the activity of SS for sucrose degradation in grains reached the maximum on the 10th DAA, then declined. Soluble sugar and sucrose contents in stems and leaf sheathes reached the maximum on the 15th DAA. Soluble sugar and sucrose contents in both basal intemodes and middle intemodes were higher than those in peduncles. Soluble sugar and sucrose contents in flag leaves, stems and sheathes, and grains were positively correlated with starch content. The activity changes of four key enzymes (AGPP SSS GBSS SBE)all showed a single peak curve. AGPP, SSS and SBE activities reached their peaks on the 25th DAA, while GBSS activity reached its maximum on the 30th DAA. The activities of AGPP, GBSS and SBE had significant correlations with amylose, amylopection and starch accumulating rate. The higher the four enzyme activities in grains (divided by grain weight) were, the higher the contents of starch and its components were. Four enzyme activities per unit grain weight in grains of weak-gluten wheat Yangmai9 were higher than those in grains of medium-gluten Ya更多还原