峨眉凤丫蕨配子体发育及卵发生的研究

用显微观察及透射电镜技术对峨眉凤丫蕨的配子体发育及卵发生过程进行了观察研究,以探讨其卵发生细胞学机制及蕨类植物演化关系。结果表明:(1)峨眉凤丫蕨孢子接种7～9d萌发,经丝状体和片状体阶段发育为心形原叶体,成熟原叶体雌雄同株,在原叶体基部产生精子器,在原叶体生长点下方产生颈卵器。(2)卵发生研究表明,峨眉凤丫蕨颈卵器产生于生长点下方的表面细胞,该细胞经2次分裂形成3层细胞,中间者为初生细胞,它经2次不等分裂产生卵细胞、腹沟细胞和颈沟细胞;新产生的卵与腹沟细胞间连接紧密,有发达的胞间连丝,随着发育,卵细胞与腹沟细胞之间产生分离腔,而腹沟细胞与卵细胞始终通过孔区相连;发育中期,卵核形成大量核外突;发育后期,在卵细胞外侧形成卵膜,孔区演变为受精孔,核外突数量减少。

Development of Gametophyte and Oogenesis in the Fern Coniogramme emeiensis

The development of gametophyte and oogenesis of the fern Coniogramme emeiensis Ching et Shing are studied by light microscopy(LM) and transmission electron microscopy(TEM).The spores germinate about 7 days after sowed.They develop into cordate prothallus through filament and plate stages.The adult prothallia,usually hermaphroditic,produce antheridia in the basal and archegonia near the apical notch of the prothallus.Studies on the oogenesis show that the archegonium of the C.emeiensis develops from a superficial cell,i.e.the initial cell of archegonium.The initial cell forms a tier of three cells by two divisions.The middle cell,i.e.the primary cell,finally develops into a neck canal cell,a ventral canal cell and an egg by two unequal divisions.Plasmodesmata connect the egg and the ventral canal cell when the egg is newly formed.During maturation,a separation cavity forms around the egg,but plasmodesmata still connect the egg and the ventral canal cell in the pore region.In the mid stage of oogenesis,the nucleus produces extensive evaginations.In the later stage of oogenesis,an egg envelop forms around the egg,the absence of egg envelope from the pore region,where the egg and ventral canal cell were formerly interconnected,produces a fertilization pore.At this stage,the numbers of the evaginations are reduced.This study elaborated the whole processes of gametophyte development,archegomium formation and oogenesis in C.emeiensis,which have some science significance to reveal the evolutionary relationship of Hemionitidaceae in the ferns.