华东安蕨卵发生的超微结构观察

核心薄囊蕨是蕨类植物中的进化类群,但对受精作用具有显著影响的卵发生研究仍较少,该文利用超微技术对其中蹄盖蕨科的华东安蕨卵发生过程进行了研究,以进一步完善薄囊蕨植物卵发生的科学资料,为理解蕨类植物的有性生殖及演化机制奠定基础。超微结构观察显示:华东安蕨的幼卵和沟细胞在颈卵器中紧密联接;随后,在卵细胞上方出现了分离腔和临时细胞壁,但在卵细胞中间孔区处卵细胞和腹沟细胞始终联接在一起;分离腔中的无定形物质沉积在卵细胞的质膜外形成了1层加厚的卵膜,而在孔区处没有形成卵膜,该位置最后形成了受精孔。在进一步的卵发生过程中,卵细胞核变得高度不规则,形成了大量的核外突和核褶皱。

Ultrastructural Observations on Oogenesis of the Fern Anisocampium sheareri

Oogenesis in Anisocampium sheareri was studied using ultrastructural methods to examine the egg structure influencing fertilization in the core leptosporangiate ferns,which is less studied.Ultrastructural observations indicated that the young egg and the canal cells are closely connected with each other in the cavity of the archegonium.Then,a separation cavity and a temporary wall are first formed above the egg during oogenesis with a pore region persistently connecting the egg and the ventral canal cell.The egg envelope is formed by deposition of amorphous materials in the separation cavity on the outer surface of plasmalemma.The egg envelope is not formed across the pore region;instead,a fertilization pore is formed.In the later stage of oogenesis,the egg nucleus becomes highly irregular and produces extensive evaginations and nuclear holds.The present investigation provided new data on oogenesis of the ferns,which contributes to understanding the cytological mechanism of the sexual reproduction of ferns and their evolution.