披针新月蕨的配子体发育及卵发生

The development of gametophytes and oogenesis in the fern Pronephrium penangianum

采用显微观察技术对披针新月蕨(Pronephrium penangianum)的配子体发育和卵发生进行了研究.结果表明:披针新月蕨孢子褐色,二面型,接种后约12 d,孢子萌发,经丝状体和片状体阶段,发育成原叶体,孢子萌发是书带蕨型(Vittaria-type),原叶体发育是槲蕨型(Drynariatype),成熟原叶体是心形,接种46 d后产生颈卵器和精子器.披针新月蕨的颈卵器起源于原叶体生长点下方的原始细胞.原始细胞经过2次不等分裂,形成3个细胞,分别是顶细胞、初生细胞和基细胞.其中,初生细胞不等分裂,形成中央细胞和颈沟细胞.随后,中央细胞不等分裂形成腹沟细胞和卵细胞.随着卵细胞成熟,颈沟细胞和腹沟细胞逐渐退化,但腹沟细胞通过孔区与卵细胞相连.卵细胞成熟后,细胞上表面具有明显的卵膜,中央具有受精孔.本研究对于完善蕨类植物生殖生物学和探讨蕨类植物的演化具有重要意义.

The development of gametophytes and oogenesis in the fern Pronephrium penangianum were investigated using microscopy technology. The results showed that the spores of P. penangianum were brown and dihedral and its spores germinated about 12 d after sowed. Then,they were developed into cordate prothallus through filament and plate stages. The spore germination was of Vittaria-type. The development of prothallus was of Drynaria-type. The mature prothallus was heart-shaped.After 46 d of spore sowing,the archegonium and antheridium were formed. The archegonium of P. penangianum originated from the initial cell beneath the growth point. The initial cell was divided into three cells by twice cell divisions,which were top cell,primary cell and basal cell. Among them,the primary cell was divided into a central cell and a neck canal cell after a division.Subsequently,the central cell underwent a division to form a ventral canal cell and an egg cell. With the development of egg,the neck canal cell and ventral canal cell gradually degenerated. Finally,only a pore region connected the egg and the ventral canal cell. When the egg cell matured,the upper surface of the cell had obvious egg envelope,and there was a fertilization pore in the center. This study is of great significance for enriching the reproductive biology of pteridophytes and exploring the evolution of ferns.