糯小麦灌浆期籽粒质量和主要营养物质动态变化

Dynamic Changes of Grain Mass and Mass Fraction of Main Nutritional Components in Grains of Waxy Wheat

为探讨糯小麦灌浆特性及其灌浆期籽粒中主要营养成分的动态变化,在大田条件下,以1个糯小麦新品种(‘长糯麦1号’)和1个非糯对照品种(‘扬麦20’)为试验材料,在花后7d、14d、21d、28d和35d测定灌浆过程中籽粒可溶性糖、蛋白质、淀粉质量分数和粒质量等指标。结果表明,‘长糯麦1号’与‘扬麦20’灌浆曲线的趋势基本一致,其渐增期的灌浆速率及渐增期、快增期和缓增期粒质量积累量均显著低于‘扬麦20’。但‘长糯麦1号’可溶性糖降解速率低,成熟籽粒中可溶性糖质量分数高于‘扬麦20’。二者的蛋白质积累动态趋于一致,呈先下降后上升的趋势。‘扬麦20’支链淀粉积累动态与‘长糯麦1号’存在显著差异,其在灌浆初期支链淀粉质量分数迅速增加,于花后28d达到顶峰,之后呈下降趋势;而‘长糯麦1号’支链淀粉质量分数增长缓慢,在花后21~28d呈"停滞"状态,于花后35d达到最大值。成熟期‘长糯麦1号’直链淀粉质量分数接近于零,总淀粉质量分数和粒质量均显著低于‘扬麦20’。综合分析认为,‘长糯麦1号’灌浆、可溶性糖转化、淀粉积累能力明显低于‘扬麦20’。因此,在糯小麦新品种选育中应把灌浆速率、可溶性糖降解转化能力和支链淀粉合成速率的提高作为重点改良方向,以提高糯小麦粒质量,进而为糯小麦育种和生产实践奠定必要的理论依据。

The objective of this study was to understand the characteristics of grain filling and dynamic changes of mass fraction of nutritional components in grains of waxy wheat,and to provide some reference for the breeding and production of waxy wheat.One waxy wheat variety（‘Changnuomai 1＇）and one check variety（‘Yangmai 20＇）were planted over two cropping seasons in experimental field of Agricultural College of Yangtze University.Grain mass,mass fraction of soluble sugar,protein and starch of two varieties were determined in different phase of grain filling.The results suggested that grain-filling rate in T_1 phase（R_1）,Grain mass accumulation in T_1 phase（W_1）,grain mass accumulation in T_2 phase（W_2）and Grain mass accumulation in T_3 phase（W_3）in‘Changnuomai 1＇were significantly lower than‘Yangmai 20＇.During grain filling period,the mass fraction of protein showed similar dynamic changes between waxy and non-waxy wheat,however,mass fraction of soluble sugar,amylose and amylopectin showed remarkable different dynamic changes between‘Changnuomai 1＇and‘Yangmai 20＇.Comparing with ‘Yangmai 20＇,‘Changnuomai 1’ had lower soluble sugar degradation rate and higher mass fraction of soluble sugar in mature grain.The mass fraction of amylopectin in ‘Yangmai 20’ increased rapidly at early stage of grain filling and reached the maximum value at 28 dafter anthesis and then decreased.The amylopectin accumulation rate of ‘Changnuomai 1’ was slower than‘Yangmai 20＇,and mass fraction of amylopectin of ‘Changnuomai 1’ reached the maximum value at 35 d after anthesis.However,‘Changnuomai 1＇had a stagnate phase of amylopectin mass fraction increase during 21-28 dafter anthesis.Grain dry mass,mass fraction of amylose and total starch of mature seeds of ‘Changnuomai 1’ were obviously lower than ‘Yangmai 20’.In conclusion,grain filling characteristic,soluble sugar degradation and starch accumulation had greatly difference between waxy wheat and‘Yangmai 20＇.Therefore,rate of grain filling,efficiency of soluble sugar degradation and transformation and synthetic rate of amylopectin should be paid more attention to in waxy wheat breeding to improve grain mass.