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作 者:郭严冬[1] 王全喜[1] 李保贵[2] 曹建国[1]
机构地区:[1]上海师范大学生命与环境科学学院,上海200234 [2]中国科学院西双版纳热带植物园,云南勐腊666303
出 处:《植物分类与资源学报》2014年第6期747-754,共8页Plant Diversity
基 金:上海市教委重点项目(12ZZ128);上海市自然科学基金(13ZR1429700)资助
摘 要:采用显微镜和透射电镜对阔叶鳞盖蕨(Microlepia platyphylla)的配子体发育和卵发生过程进行了观察,以阐明其卵发生的细胞学机制,探讨其演化地位。阔叶鳞盖蕨孢子褐色,四面体形,具三裂缝,接种5-10 d后孢子萌发,经丝状体和片状体阶段发育为心形原叶体,原叶体发育是铁线蕨型,通常为雌雄异株,精子器产生于不规则配子体的表面,颈卵器产生于心形原叶体生长点的下方,性器官是薄囊蕨型。卵发生研究表明,阔叶鳞盖蕨颈卵器产生于生长点下方表面细胞,经两次分裂形成了顶细胞、初生细胞和基细胞。其中初生细胞再经两次不等分裂产生卵细胞、腹沟细胞和颈沟细胞,此3个细胞通过胞间连丝紧密相连,随发育,腹沟细胞与卵细胞间形成了分离腔,但在孔区处始终通过胞间连丝相连,成熟卵细胞上形成了卵膜和受精孔,卵核表面产生了核外突,通过比较表明阔叶鳞盖蕨卵发生与蕨(Pteridium aquilinum)卵发生相似。Gametophyte development and oogenesis of the fern Microlepia platyphylla were studied using microscopy and transmission electron microscopy. The present studies have significance in clarifying the cytology mechanism of oogenesis and reveal the evolution status of M. platyphylla. The spores are brown, tetrahedral and trilete. The spores germinate about 5-10 days after sowed. They develop into cordate prothallus through filament and plate stages. The development of the prothallus is the Adiantum-type. The adult prothallus are usually diecious. Antheridia (an) us- ually are produced on irregular prothallus and archegonium (ar) are produced near the apical notch of the heart- shaped prothallus. Sex organs are Leptosporangiate-type. Studies on the oogenesis showed that the archegonium de- velops from a superfacial initial cell under the growth point. Two divisions of the initial cell result in a tier of three cells, i. e the upper cell, primary cell and basal cell. The primary cell finally develops into a neck canal cell, a ven- tral canal cell and an egg by two unequal divisions. The three cells were associated closely with each other. Then the neck canal cell and the ventral canal cell degenerated gradually. A separation cavity was formed between the ventral canal cell and the egg cell, but plasmodesmata still connected the ventral canal cell and the egg in pore region. Egg envelope and fertilization pore were formed in the matured egg. Nuclear evaginations were produced from the nuclear surface. It was showed that oogenesis of the fern M. platyphylla is similar to the fern Pteridium aquilinum.
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