大豆子叶发育过程中的显微结构变化

东农47（Glycin max L．‘Dongnong47’）种子发育过程中，子叶贮藏细胞大量合成和积累贮藏物质，在光镜和电镜下观察了贮藏物质的积累过程。结果表明：在子叶发育过程中，淀粉粒在开花45天前逐渐增多，之后则逐渐减少。生理成熟期时，子叶细胞中仅有少量淀粉粒存在。淀粉粒的减少可能与细胞发育过程中能量需求有关。蛋白质体经历了由少到多、由不均匀分布向均匀分布的转变。脂体在积累的过程中数量逐渐增多，起初仅有少量在细胞壁周围散布。生理成熟期时脂体垂直于细胞壁和蛋白质体的表面呈镶嵌状排列。脂体除了在细胞质中分布外，在蛋白质体中也有分布。开花25天后予叶细胞的叶绿素含量呈下降趋势。对质体片层结构观察表明，片层在逐渐减少，到成熟时几乎消失。子叶的光合活性逐渐下降直至完全消失，由具光合活性的器官转化成贮藏器官。

Microstructural changes of cotyledon cells in soybean during seed development

Accumulation and synthesis of reserve metabolites occurring in cotyledon cells during seed development was examined in Glycin max L. ‘Dongnong 47＇ by light and electron microscopy. The results showed that starch grain increased gradually before 45DAF and then decreased gradually. At the physiological maturation, there were only small amount of starch granules in the cotyledon cells. The decrease of starch granules may be related to the demand of energy in the cell development. Protein bodies increased and changed from inhomogeneous distribution to uniform distribution. The number of lipid bodies increased gradually. Initially only a few of them dispersed near the cell walls. They were perpendicular to the cell walls and to the surface of protein bodies at the physiological maturation. They are distributed not only in the cytoplasm but also in protein bodies. The chlorophyll content of cotyledon cells was downtrend after 25 DAF. The number of lamellar decreased and almost disappeared at the time of seed maturation, demonstrating that photosynthetic activity of cotyledon reduced and cotyledon changed into storage organ from the organ which had photosynthetic activity.