Abstract: In order to prove up mechanism of rice endosperm development and aleurone layer formation， structure changes of rice aleurone cells and inner endosperm cells during caryopsis development were observed under light microscope and electron microscope．Kinds and relative content of endosperm cell elements were analyzed with energy spectrometer．The results show  that aleurone cells are differentiated from endosperm epidermis．The contents of P，K，Mg and Ca mineral elements in aleurone cells are obviously higher than those  in inner endosperm cells．During the early development stage，aleurone cells contain many mitochondria，spherosomes and small vacuoles；during the middle and late development stages，small vacuoles accumulate protein and mineral elements to form aleurone granules．During middle and late development stages of endosperm，nuclei of endosperm cells distort and degenerate when cells accumulate starch；however，nuclei of aleurone cells do not degenerate during the development．The formation of aleurone layers is related to accumulation of mineral elements，lipids and other “filling wastes” (not endosperm cell reserve substance things)．Therefore，cell layers of  the aleurone layer in dorsal caryopsis  through which  more nutrients   are transported  overnumber those  in ventral and side caryopsis．Development of cereal endosperm  should be  divided into four stages: coenocyte stage，cellularization stage，differentiation stage and maturation stage．

Key words: rice, endosperm, aleurone layer, development

摘要： 为了探明水稻胚乳发育的过程和糊粉层形成的机理， 用光学显微镜和电子显微镜观察了水稻糊粉层细胞和内胚乳细胞在颖果发育过程中的结构变化，用能谱仪分析了胚乳细胞中元素的种类和相对含量。结果表明, 糊粉层细胞是由胚乳表层细胞转化而来的。糊粉层细胞中的P、K、Mg和Ca等矿质元素含量要明显高于内胚乳细胞。发育初期糊粉层细胞中富含线粒体、圆球体和小液泡；发育中后期小液泡积累蛋白质和矿质元素而形成糊粉粒。在发育中后期，内胚乳细胞随着细胞内淀粉体的充实，细胞核发生形变而衰亡；而糊粉层细胞的核在发育过程中不消亡。糊粉层的形成与表层细胞积聚矿质和脂类等“灌浆废物”(指非内胚乳细胞的贮藏物)有关。因而，转运灌浆物质多的胚乳背部，其糊粉层细胞的层数要比腹部和侧部多。谷物胚乳发育分为游离核期、细胞化期、分化期和成熟期四个时期。

关键词: 水稻, 胚乳, 糊粉层, 发育