摘要
用 GMA半薄切片技术对 AP 不同类型胚囊的形成与发育过程的研究表明 ,AP 不同类型胚囊是由不同的发育途径形成的。其中 5- 2 - 1型、6- 2 - 0型和 5- 3- 0型等胚囊是由 3条不同的新的蓼型变异型发育途径形成的。决定这 3条途径变异的因素有 :功能大孢子核的位置变化、胚囊核分裂纺锤体走向的改变、胚囊核的不同步分裂和分裂后形成的核定位不同等。双套结构胚囊的形成可能由于下极核和1个卵原始细胞出现移动错位造成的 ,即本应移向胚囊中央的下极核滞留在珠孔端 ,而本应留在珠孔端的卵原始细胞却取代下极核移向中央。
The process of different types of embryo sac formation was studied in APⅣby using the technic of seni thin sectioning. Different types of embryo sacs were formed by different ways of development. The embryo sac of 5 2 1 type, 6 2 0 type, and 5 3 0 type were formed through three respectively new Polygonum variant ways of development. The factors causing the three different ways of development were positional change of functional megaspore nucleus, change of orientation of the dividing spindle of the embryo sac nucleus, nonsynchronous division of embryo sac nucleus and orientation of nucleus after division. Double set of embryo sac resulted possibly from mutual change in position of the primordial low polar nucleus and the primordial egg cell, i. e. the polar nucleus did not move toward the center of the embryo sac, but remained in the micropyle part, whereas the egg cell moved to the center and replaced the low polar nucleus.
关键词
水稻
胚囊
形成
多胚水稻品系
发育
Rice
Polyembryony
Embryo sac formation
Polyembryonic rice strain AP Ⅳ
Two equal polar type
