祝光苹果大孢子发生和雌配子体的发育

从孢原细胞至雌配子体形成约需14天,其中大孢子发生历时8天;雌配子体发育历时6天。当花序基部幼叶展开,花蕾分离,顶花花冠露红时,大孢子母细胞形成。当顶花花冠露出与花萼等长时,大孢子母细胞经减数分裂形成四个直线排列的大孢子。合点端大孢子具功能。开花前一日,雌配子体形成。雌配子体发育属蓼型。 在大孢子发生和雌配子体发育过程中,淀粉经胎座向胚珠中转移。至开花时,胚珠中淀粉分布普遍。淀粉多聚集成较大的团粒存在。只胚囊中为分散的单粒淀粉。

The Megasporogenesis and the Development of Female Gametophyte of Apple American Summer Pearmam

It lasted 14 days for archesporial cell to develop into female gametophyte. The megasporogenesis lasted 8 days, and the development of female gametophyte lasted 6 days. When the flower buds separated and corolla facrogenous, flowers appeared and the megasporocyte formed. When corolla appeared and it's length equaled to that of calyx, meiosis of megasporocyte completed and developed into four megaspores. The megaspore near chalaza had developed 1 day before blossom femal gametophyte had formed and the type of it's development belonged to Polygonum type. The starch grains transfered into ovule through the placenta, in the course of the megasporogenesis and the development of femal gametophyte. When flowers appeared, starch grains existed widely, gathering into larger particles in the ovule, with only single grain scattering in the embryo sac.