糯小麦籽粒糖降解和淀粉积累特性研究

 【目的】比较糯小麦籽粒可溶性糖含量和淀粉含量与非糯小麦的差异，研究其花后籽粒中糖降解和淀粉积累特点，为糯小麦的育种和生产应用提供参考。【方法】2004～2005年度测定不同来源的17个糯小麦品系和4个非糯对照品种籽粒可溶性糖和淀粉含量，2005～2006年度选择其中3个糯小麦品系和2个非糯对照品种研究其花后籽粒中糖降解和淀粉积累动态。【结果】15个糯小麦品系籽粒可溶性糖含量显著高于所有对照品种，另2个糯小麦品系籽粒可溶性糖含量显著高于对照扬麦12和扬麦5号，而与扬麦158和扬麦9号差异不显著。4个对照品种之间淀粉含量差异不显著，扬麦9号最高，扬麦158最低；供试的17个糯小麦品系籽粒淀粉含量均低于对照扬麦9号，其中13个糯小麦品系低于扬麦158。籽粒中糖降解和淀粉积累动态研究表明花后10～17d糯小麦籽粒可溶性糖含量下降速率小，开花17d后3个糯小麦品系先后都经历一个淀粉含量增长的相对“停滞”阶段。【结论】糯小麦成熟期籽粒中可溶性糖含量高，淀粉含量低，可能与其灌浆前期籽粒中可溶性糖转化效率低，淀粉积累中后期经历一个相对“停滞”阶段有关，这主要是由于GBSS的缺失导致糯小麦不能合成直链淀粉改变了糯小麦糖转化和淀粉积累特性。在糯小麦育种中应加强对花后籽粒中可溶性糖转化效率和淀粉积累动态的研究，选择灌浆前期糖转化效率高，淀粉含量增长“停滞”阶段出现较迟的品种，以改良糯小麦籽粒饱满度。

Characteristics of Sugar Degradation and Starch Accumulation in Waxy Wheat Grains After Anthesis

Abstract: 【Objective】 The aim of this experiment is to discover the characteristics of sugar degradation and starch accumulation in waxy wheat by comparing its grain soluble sugar content and starch content with non-waxy wheat, and by studying the dynamics of sugar degradation, starch accumulation in waxy wheat grains after anthesis. 【Method】 Soluble sugar content and starch content in grains of 17 waxy wheat varieties from different crosses and 4 non-waxy wheat varieties(check) were determined in 2004-2005, and 3 waxy varieties and 2 check varieties were selected to study the process of sugar degradation and starch accumulation in grains after anthesis in 2005-2006 . 【Results】In terms of grain soluble sugar content, 15 waxy wheat varieties were significantly greater than all check varieties, and the other 2 waxy wheat varieties were significantly greater than Yangmai 12 and Yangmai 5. As grain starch content, all waxy wheat varieties were lower than Yangmai 9, 4 of which were higher than Yangmai 158. There was no significant difference in grain starch content among check varieties, although Yangmai 158 was lower than Yangmai 9, Yangmai 5 and Yangmai 12.The decreasing rate of soluble sugar content in waxy wheat grains was slow during the period from the 10th day to the 17th day after anthesis. All 3 waxy wheat varieties tested had a “pause stage” of starch content increase after the 17th day post-anthesis, during which starch content stopped increasing. 【Conclusion】Soluble sugar content in waxy wheat grains was higher, but starch content was lower than check varieties. The probable reason might be the low efficiency of sugar transformation at the beginning stage of grain filling and the existence of “pause stage” due to the absence of GBSS. Much attention should be paid to study on the efficiency of sugar transformation and the process of starch accumulation, so as to breed varieties with high efficiency of sugar transformation and late appearing of “pause stage” during starch accumulation.