矮沙冬青雌配子体及胚胎发育研究

Study on the development of female gametophyte and embryo in Ammopiptanthus nanus

矮沙冬青子房单心皮1室,边缘胎座,弯生胚珠,胚珠具双珠被、厚珠心。大孢子孢原细胞发生于珠心表皮下,大孢子母细胞减数分裂形成直线排列的四分体,合点端大孢子具功能,并按蓼型胚囊发育,雌配子体成熟于4月中旬。双受精后,胚乳发育为核型。在矮沙冬青大孢子发生、雌配子体和胚胎发育过程中未发现异常现象,因此认为矮沙冬青濒危不存在雌性生殖结构与发育过程异常的内在因素。

Simple ovary,the placentation is brink. The ovules are campylotropous. The ovule is bitegmic and crassinucellate. The megaspore archesporium is initiated from sub-epidermis of nucellus. The megaspore mother cell divides into linear tetrad after meiosis. The chalazal end megaspore is functional one. The embryo sac is the Polygonum type when the embryo sac is mature. Female gametophyte is mature in the middle ten days of April. The endosperm develops into nuclear type after fecundation. The abnormal development is not found in megasporogenesis and the development of female gametophyte and embryo of Ammopiptanthus nanus. It is suggested that the endangerment of this species is not related to megasporogenesis and the development of female gametophyte and embryo.