小麦胚乳A、B型淀粉粒的形成与生长特征及氮素调节

Formation and Developmental Characteristics of A and B Type Starch Granule in Wheat Endosperm and Response to Nitrogen

为研究小麦胚乳淀粉粒形成与生长特征,以优质小麦品种藁城8901为材料,在缺氮（对照）和施氮条件下,对籽粒发育过程中淀粉粒的产生、体积与数目分布及粒径变化进行比较。结果表明,花后4 d,小麦胚乳已出现A型淀粉粒,其中施氮处理粒径显著高于对照,说明氮素有利于早期淀粉粒的产生。花后10 d,又产生了一个新的小淀粉粒群体,即B型淀粉粒。花后10～12 d,施氮处理的粒径显著低于对照,可能是这个阶段施氮能促进小麦产生了更多的小（B型）淀粉粒,说明这个时期淀粉粒的生长以数目增长为主。花后14～17d,施氮处理淀粉粒粒径显著高于对照,说明这个时期淀粉粒生长以个体体积增大为主。花后24 d,〈0.8μm淀粉粒数目急剧增加,表明此期又产生了一个小淀粉粒群体。花后28 d,施氮处理〈0.8μm淀粉粒数目仍不断增加,表明施氮能促进灌浆后期籽粒产生更多的小淀粉粒。通过透射电镜观察发现,小淀粉粒是由大淀粉粒分裂而来的,单个存在。小麦胚乳A型淀粉粒形成和发育时期基本在花后14 d之前,而B型淀粉粒在成熟前,其体积和数目一直在增加。施氮有利于胚乳A、B型淀粉粒个体的增大和数目的增多。

Formation and developmental characteristics of granules of wheat endosperm were studied using wheat cultivar Gaocheng8901 as materials in this study. Under nitrogen deficiency（ control） and nitrogen fertilizer conditions,the production,volume and number distribution of starch grain as well as change of grain sizes were compared during grain development. The results showed that the A- type granules were formed at 4 day post anthesis（ DPA）,and wherein grain size with nitrogen treatment was significantly larger than that of the control,indicating that nitrogen can promote the production of starch grain in early stage. Then smaller B- type granules were produced at 10 DPA.The diameter of granules in nitrogen treatment group was lower than that in control at 10 ~ 12 DPA,and the reason may be that nitrogen could accelerate the formation of more starch granules compared to the control. It suggested that starch granules mostly increased in amount. The diameter of granules in nitrogen treatment was greater compared with the control at 14 ~ 17 DPA,indicating that starch granules mostly increase in individual size. At 24 DPA, 0. 8 μm starch granules were rapidly increased,indicating that a starch granule group was produced in this stage. At 28 DPA, 0. 8 μm starch granules were also rapidly increased after nitrogen treatment,demonstrating that nitrogen treatment can promote the development of more starch granules at the late period of grouting. Transmission electron microscopic observation showed that small starch granules were divided from large starch granules and exist individually. Type A starch granules of wheat endosperm was formed and developed before 14 DPA,while the size and amount of type B starch granules were always increased before type B starch granules are matured. Nitrogen treatment can promote the enlargement and increase of type A and B starch granules.