糜子的受精过程和胚的发育

本文应用光学显微镜和石蜡制片法,对糜子的受精过程与胚的发育进行研究,结论如下:开花2h 后后,精核进入卵细胞;开花4h 后,精核的染色质逐渐分散,并出现核仁,受精卵内有一大而明显的雌性核仁和一较小的雄性核仁,此时合子形成,开花10h 后,合子进行1次分裂,糜子合子静止期长达4h 左右。2细胞原胚时,胚乳处于6个游离核时期。糜子的胚胎发育为紫菀型。合子无极性,第1次分裂为横分裂。胚发育经过原胚、椭圆形胚再经胚分化期和成熟期发育为成熟胚。受精前,两极核紧贴,不合并,位于卵细胞的合点端。受粉2h 后,精子进入一个极核,精核与极核融合过程同精核与卵核的融合过程相同;开花4h 后,形成初生胚乳核;开花5h 后初生胚乳核进行第1次分裂;胚乳发育为核型,游离核分裂为有丝分裂,球形胚期胚乳开始细胞化。

Fertilization and Embryogenesis of Panicum miliaceum

This paper presents detailed report on the process of fortilization and devolopment of embryo and endosperm in Panicum mitiaceum L.About two hours after anthesis one sperm nucleus enters into the egg nucleus;Four hours after anthesis the sperm chromatin disperses and the nucleolus appears. There is a large female nucleolus and a small male nucleolus in the fertilized egg nucleus at the time of zygote fermation;Ten hours after anthesis the first mitotic division take places.The dormant stage lasts about four hours. At two cell stage,The endosperm pessesses six free nuclei. The embryogeny conforms to ASTERAD TYPE.The first division of zygote is transversal division.During the dormant stage the zygote shows no polarity.The embryo development goes throuth the following stages;Proembryo formation,illipsoidal differentiation and maturation. Before fertilization the two polar nuclei situated in the chalazal end of the egg cell are close to each other,but not fused.Two hours after anthesis the second sperm nucleus enter into one polar nucleus and fusion takes place. The process of fusion is similar to but faster than,that of the first sperm nucleus with the egg nucleus;Three hours after anthesis the primary endosperm nucleus is formad;Four hours after anthesis the first mitotic division in the primary endosperm nucleus takes place.The endosperm devolopment follows the nuclear pattern.The endosperm cell formation begins at the micropylur end of the embryo sac.