珍稀濒危蕨类植物金毛狗配子体发育及无配子生殖的观察

Observation on gametophyte development and apogamy of the endengered fern Cibotium barometz

金毛狗[Cibotium barometz(L.)J.Sm.]为国家二级重点保护野生植物,是珍稀濒危蕨类植物的重要类群。本研究通过孢子无菌培养,对金毛狗配子体发育及其无配子生殖现象进行观察。结果表明:金毛狗孢子为黄色,近四面体型,三裂缝,远极面具条状纹饰,萌发类型为书带蕨型(Vittaria-type),多数配子体的发育类型符合铁线蕨型(Adiantum-type)。孢子播种约40 d后,原叶体开始产生精子器,颈卵器晚于精子器出现。金毛狗属于兼性无配子生殖,无配子生殖发生于增厚原叶体的两翼上缘。与同期有性生殖的组培植株相比,无配子生殖组培植株的特征在于:植株个体、复叶及小叶均小于有性生殖植株,三回羽状复叶特征较为明显,复叶叶柄的毛密而长,染色体倍性为有性生殖植株的一半。

Cibotium barometz（L.） J. Sm., an important group of the endangered ferns, is listed in the Category II of State Special Protected Plants. In present study, the gametophyte development and apogamy of Cibotium barometz were investigated by the sterile culture of spores. The results showed that spores were yellow, tetrahedral and trilete. There were strip ornamentations on the distal surface of spores. The germination type of spores was Vittaria-type. The gametophyte development was mainly Adiantum-type. Antheridia appeared after about 40 days of spore cultivation. Archegonia appeared later than antheridia. Apogamy of Cibotium barometz was facultative, which happened at the apical region of thickened prothallus. Compared with in vitro sporophytic plantlet, in vitro apogamic plantlet had smaller frond and leaflet, and characters of tripinnate leaf was more significant. Hairs on the stipe of apogamic plantlet were denser and longer. Ploidy of apogamic plantlet was half of sporophytic plantlet.