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作者	单位
余徐润，邵珊珊，于恒，张静，熊飞，王忠	(扬州大学江苏省作物遗传生理国家重点实验室培育点/粮食作物现代产业技术协同创新中心，江苏扬州 225009)

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中文摘要:

为探明小麦、水稻、玉米果皮淀粉体的发育、形态和结构特征的差异，以小麦“烟农19号”，水稻“扬稻6号”和玉米“扬糯1号”不同发育天数的颖果为材料，采用树脂切片、扫描电镜观察、X-射线衍射(XRD)、傅里叶变换远红外光谱(FTIR)相结合的技术，对这三种谷物果皮淀粉体的发育、形态和结构特征进行了比较分析。结果表明，小麦颖果背部和腹部外果皮在早期都有小颗粒淀粉体积累，后期逐渐降解；水稻和玉米颖果背部外果皮在早期积累小颗粒淀粉体，随后逐渐降解，腹部外果皮不积累淀粉体。小麦、水稻、玉米中果皮细胞均积累较多的淀粉体，随着颖果的发育，小麦和玉米果皮细胞发生了明显的细胞程序性死亡，淀粉体从细胞中流失并不断降解，水稻中果皮程序性死亡进程不明显，细胞只是发生收缩和变形并伴随有淀粉体的降解。小麦和水稻果皮横细胞早期积累叶绿体，随着颖果的发育，叶绿体中开始积累淀粉粒，随后不断降解；玉米横细胞不积累叶绿体，只有少量的淀粉体积累，随后淀粉体降解。小麦果皮淀粉体分为单粒和复粒淀粉两种，淀粉粒呈现圆球状和不规则状；水稻和玉米果皮淀粉体为复粒淀粉，淀粉粒多呈不规则状，部分玉米淀粉粒呈多面体状。小麦、水稻、玉米果皮淀粉表现出相似的XRD和FTIR图谱, 但在XRD波谱的2θ角17°和18°衍射峰及FTIR光谱的995和1 022 cm^-1共振峰强度不同，玉米果皮淀粉的相对结晶度最高，小麦次之，水稻最低；淀粉粒表层有序度以水稻最高，玉米次之，小麦最低。以上结果说明，在小麦、水稻、玉米果皮不同部位，淀粉体的发育和形态上存在较多个异同点，果皮淀粉粒内部结晶度和表层结构有序度存在显著差异。

英文摘要:

The aim of the study was to investigate the developmental, morphological, and structural characteristics of amyloplasts in pericarp of wheat, rice and maize caryopses. Pericarp amyloplasts of three types of cereal crops cultivars, i.e. wheat cultivar “Yannong 19”, rice cultivar “Yangdao 6”, and maize cultivar “Yangnuo 1”, were studied using resin slice, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectrum techniques. The main results were as follows: Small amyloplasts were accumulated in dorsal and abdominal regions of wheat epicarp and were degraded thereafter; small amyloplasts were accumulated in dorsal regions of epicarp of rice and maize and were degraded thereafter. Many amyloplasts were accumulated in mesocarp in pericarp of wheat and maize, released from pericarp cell where the process of programmed cell death happened, and finally degraded. It is worth noting that amyloplasts were degraded in rice mesocarp where the process of programmed cell death was not obvious. Some starch granules were first accumulated in chloroplast in wheat cross cell and rice pericarp and were gradually degraded with caryopsis development. Few amyloplasts were accumulated in maize cross cell where no chloroplast were synthesized and then degraded. Wheat pericarp amyloplasts were compound or single starch granules, which were spherical and irregular in shape. Rice and maize pericarp amyloplasts both were compound starch granules, which were irregular in shape and some maize pericarp starch granules were polyhedral in shape. Starches from wheat, rice and maize pericarp exhibited similar XRD and FTIR spectra. They differed in diffraction peak at 2 θ 17° and 18° and resonance peaks at 995 cm^-1 and 1 022 cm^-1. Maize pericarp starch showed the highest relative degree of crystallinity, followed by wheat and rice pericarp starches. Rice pericarp starch presented the most ordered structure in external region of starch granules, followed by maize and wheat pericarp starch granules. The results indicated that there are many similarities and differences on the development and morphology of starch granules in different regions of wheat, rice and maize pericarp. The relative degree of crystallinity and ordered structure in external region of granules significantly differed between these starches.

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