谷子胚和胚乳的发育

THE DEVELOPMENT OF EMBRYO AND ENDOSPERM IN SET ARIA IT ALICA BEAUV

合子的第一次分裂为斜的横分裂。胚发育至棒状原胚后，胚体顶端一侧的细胞加速分裂形成一团分生组织细胞。由这团分生组织细胞分化盾片、胚芽鞘、胚芽生长点和胚根。胚体的其它部分参与部分盾片和胚根鞘的构成。胚柄不参与胚的组成。胚无外胚叶。胚胎发育属禾本型。核型胚乳。从胚囊壁产生的自由生长壁把胚乳游离核隔开形成一层胚乳细胞，然后这层细胞平周分裂使胚乳细胞变成二层，以后的胚乳细胞增殖以细胞有丝分裂方式进行。胚乳的最外层细胞发育为糊粉层细胞。其余的胚乳细胞充满淀粉粒。反足细胞于胚器官分化前夕开始退化解体。

The first division of zygote is obliquely transverse. After the developmental stage of cdub-like proembryo;cells on one side of upper part of proembryo accelerate division and form a groupof meristematic cells from which are differentiated scutellum,coleoptile,the growing point ofplumule and radicle,the other part of proembryo participates in the formation of partial scutellumand coleorhiza. The suspensor doesn’t take part in the structure of embryo without epiblast. Theembryogeny conforms to Graminad type. The endosperm is of nuclear type. The freely growing cellular wall separates free endospermunclei into a layer of endosperm cells which divide periclinally into two layers,subsequently thenumber of endosperm cells increases through mitoses. All endosperm cells are stuffed by starchgrains except the outmost layer of endosperm cells differentiates into aleturone layer.