草莓胚胎发育研究

以沈阳农业大学培育的“明旭”草莓品种为材料,采用常规石蜡切片法,结合整体透明与显微解剖技术,对草莓胚和胚乳的发育过程进行观察,其结果如下:草莓离生单雌蕊每个子房内具一枚横生胚珠,单珠被,厚珠心。成熟胚囊为蓼型。卵细胞较大,呈洋梨形。助细胞略小,核大质浓。极核有时融合成次生核。反足细胞不明显。胚囊窄而长。合点端有明显的承珠盘结构。个别胚珠中有双胚囊现象。胚的发育过程与大多数双子叶植物基本一致。从受精卵发育到二细胞原胚过程中,合子第一次分裂形成顶细胞和基细胞。继而顶细胞斜向纵裂,基细胞横裂。由基细胞分裂来的近合点端的一个细胞再发生纵裂,和从顶细胞分裂来的细胞共同参与胚体的形成,进而产生多细胞球形原胚,心形胚,鱼雷形胚,成熟胚。当成熟胚形成时,胚柄将逐渐消失。草莓胚发育属紫菀型,胚乳发育为核型。

Study of Fragaria ananassa Duch. Embryo Development

"Ming Xu" Fragaria ananassa Duch. cultured by Shenyang Agriculture University was used as research material. Routine Paraffin wax slice combined with overall transparency and microscopic dissection technology were used to observe Fragaria ananassa Duch. embryo and the developmental process of endosperm. The results were as follows: Each ovary in the Apo-Monocarpous pistil of Fragaria ananassa Duch. had one hemianatropous ovule with single integument and thick nucellus. Mature embryo sac was polygonum type shaped. Egg cells were relatively large and pear shaped. Synergid was relatively small with large nucleus and thick cytoplasm. Polar nucleus sometimes fused to form cecondary nucleus. Antipodal cells were insignificant. Embryo sac was narrow and long. Chalaza end had characteristic hypostase structure. A few ovules had two embryo sacs. The process of embryo development was consistent with most Dicotyledon. In the developmental process from zygote to two celled proembryo, zygote underwent first division to form apical cell and basal cell. Then apical cell underwent perpendicular division while basal cell underwent transverse division. Then the one cell near Chalaza end, which was derived from basal cell, underwent perpendicular division again, together with cells derived from apical cell, they formed embryo proper, and then sequentially formed multicellular spherical proembryo, heart-shaped embryo, Torpedo-shaped embryo, mature embryo. When mature embryo formed, suspensor would gradually disappear. Fragaria ananassa Duch. embryo development belonged to asterad type, endosperm development belonged to nuclear type.