西藏冬青稞胚乳淀粉粒发育特征研究

为了解青稞胚乳淀粉及淀粉粒形成与生长特征,以西藏育成青稞品种冬青8号为材料,对籽粒发育过程中胚乳灌浆速度、淀粉积累量及淀粉粒的产生、二维面积、粒径变化进行了分析。结果表明,胚乳发育过程中,干物质和淀粉积累量呈S型曲线,两者呈正相关。花后5d,青稞胚乳中可零星见到粒径和二维面积较小的A型小淀粉粒;花后10~15d,A型小淀粉粒数量显著增大,但粒径和二维面积增加较慢;花后20d,B型小淀粉粒可能已经形成,与A型小淀粉粒组成一个复合群体;花后25d,形成了粒径10μm的A型淀粉粒、粒径5~10μm的B型淀粉粒和粒径5μm的C型淀粉粒;花后30~55d,不同粒径的淀粉粒数量和二维面积逐渐增加,其中,C型淀粉粒数量不断增加直至籽粒成熟。青稞成熟籽粒胚乳中,淀粉粒的粒径为1.45~44.76μm,二维面积为3.56~1 750.8μm2;A型淀粉粒形状为近圆形,表面光滑,个别表面附着有C型淀粉粒,B型淀粉粒形状有近圆形、椭圆形多种类型,C型淀粉粒形状比B型淀粉粒的变异更大。

Developmental Characteristics of Starch Granule in Endosperm of Tibetan Winter Hulless Barley

To study the formation and growth of hulless barley endosperm starch and starch granules,hulless barley Dongqing 8(cultivated in Tibet) was chosen as the target material to analyze endosperm filling rate,starch accumulation as well as the formation,2D area and size of starch granules in the process of granule development.The results showed that during the development of endosperm,dry matter auumulation and starch accumulation perform an S curve,and are positively related to each other.On the 5 days post anthesis(DPA),A-type starch granules with small sizes and 2D areas can be sparsely seen in hulless barley endosperm.During 10 to 15 DPA,the number of small A-type starch granules increased significantly,but their size and 2D area showed a slow increase.On 20 DPA,B-type small starch granules may come into being and they will be combined with A-type small starch granules to form a composite polymer.On 25 DPA,the size of A-type starch granules was above 10 μm,and the size of B-type starch granules ranged from 5 to 10μm,and the size of C-type starch granules was less than 5 μm.During 30 to 55 DPA,the number and 2D areas of starch granules with different sizes increased a lot,and the number of C-type starch granules grew until the granules mature.Diameter of starch granules in mature granule endosperm of hulless barley ranged from 1.45 μm to 44.76 μm,and the 2D area ranged from 3.56μm2 to 1 750.8μm2.A-type starch granules is roughly spherical with smooth surface.C-type starch granules adhered to surface of some A-type starch granules.Btype starch granules are shaped in sub-spherical and oval.Shape of type-C starch granules had greater variation than that of B-type starch granules.