Embryogenesis,Germination,Structure and Cotyledon Dimorphism of Zea mays Embryo  

玉米胚胎发育、萌发与胚的结构及子叶二型性(英文)

作　　者：冯九焕[1] 徐雪宾[1] 刘向东[1] 章崇玲[2] 梁秀兰[3] 吴万春 

机构地区：[1]华南农业大学植物分子育种研究中心,广州510642 [2]华南农业大学生命科学学院,广州510642 [3]华南农业大学农学院,广州510642

出　　处：《Acta Botanica Sinica》2003年第6期712-723,共12页Acta Botanica Sinica（植物学报：英文版）

基　　金：广东省自然科学基金 (990 70 7);高等学校博士学科点专项科研基金(2 0 0 10 5 64 0 0 7);国家自然科学基金(3 9970 0 48)~~

摘　　要：A series of new cognitions on the morphogenesis of maize ( Zea mays L.) embryo have been obtained with scanning electron microscopy and semi-thin section techniques. 1. The proembryo. The proembryo from zygotic cell divisions may be divided into three parts: proper, hypoblast and suspensor. The suspensor is short and small, and only exists transiently. As to the hypoblast there is a growth belt, which promotes elongation of the hypoblast. Eventually the upper portion of the hypoblast contributes to the formation of the coleorhiza and the remainder dries up, sticking to the end of the coleorhiza. 2. The maize embryo possesses dorsiventrality and cotyledon dimorphism. During early proembryo stage, the dorsiventrality appears in the proper of the embryo. On the ventral side, the cells are small with dense cytoplasm and few vacuoles. On the dorsal side, the cells are larger with lower cytoplasmic density and have more vacuoles. During later proembryo stage, the proper develops into two parts: the ventrum and the dorsurn. The ventrum rises up from the center of the ventral side. The dorsurn is composed of the marginal area of the ventral side and the whole dorsal side of the proper. During young embryo development, the ventrum differentiates into the coleoptile, apical meristem, hypocotyl, radicle and the main part of the coleorhiza. What is more important, the emergence of coleoptile primordium and radicular initials occur at the axis of the proper, then the coleoptile primordium expands from its two ends toward left and right to form a ring, and the endogenous radicular initials expand in all directions to form a conical radicular tip. All these morphogenetic activities of the ventrum follow a bilateral symmetrical pattern. The dorsurn forms the scutellum. primordium. Then the scutellum primordium, expands rapidly toward the left, right, front and back, while thickening itself, so as to make all components originating from the ventrum become hidden in the longitudinal groove of the scutellum. Lastly, the left and ri运用扫描电镜与半薄切片技术 ,观察了玉米 (ZeamaysL .)的胚发育过程 ,得到以下认识 :第一、关于原胚。玉米合子细胞分裂形成的原胚分为胚柄、胚基与胚体三部分。胚柄短小 ,寿命短暂。胚基具有生长带 ,纵向伸长长度大 ,胚基的上部参与形成胚根鞘 ,其余部分干缩后附在胚根鞘末端。第二、玉米胚的背腹极性及二型子叶。原胚初期胚体出现背腹极性 ,腹面的细胞小 ,细胞质稠密 ,液泡较少 ;背面的细胞较大 ,细胞质稠密度略低 ,液泡较多。原胚后期胚体分化为腹部与背部 ,腹部从腹面的中央突起 ,背部在腹部的周围 (从左至右侧 )及整个胚体背面。进入幼胚时期 ,腹部分化为胚芽鞘、生长锥、胚轴、胚根和胚根鞘 (大部分 )。期间 ,胚芽鞘原基和根原始细胞的分化都从胚体的中轴部位开始 ,然后向两侧和四周扩展 ,表现出胚体腹面形态的两侧对称性。原胚的背部形成盾片原基 ,盾片原基经历向左、右、上、下的迅速扩展和加厚的生长 ,将整个腹部所分化形成的构件藏于盾片的纵沟之中 ,最后盾片从纵沟的边缘长出的左、右侧鳞均向胚体的中轴线生长 ,完整显示出玉米胚腹面的两侧对称。玉米胚由腹部顶端形成胚芽鞘和生长锥的情况与水稻胚的胚芽鞘 (顶生子叶 )和生长锥的形成相同 ,玉米的胚芽鞘也是顶生子叶 ,盾片则是侧生子叶。

关 键 词：Zea mays EMBRYOGENESIS hypoblast dorsiventrality cotyledon dimorphism embryonic envelope (lateral cotyledon) coleoptile (apical cotyledon) 

分 类 号：S513[农业科学—作物学]