假瘤蕨属植物配子体与幼孢子体发育的比较形态学研究(英文)

Comparative Morphology of Development of the Gametophyte and Juvenile Sporophyte of Phymatopteris

配子体及幼孢子体发育过程对蕨类植物的系统学研究具有重要意义,但在假瘤蕨属植物中较少报道。本研究比较了3种假瘤蕨属植物的配子体及幼孢子体发育过程:孢子均为单裂缝,萌发类型为书带蕨型。原叶体发育为槲蕨型。丝状体2～6细胞,成熟配子体心形,中肋明显加厚。配子体两性,在播种后48～55d产生精子器,之后15～18d产生颈卵器。播种后80～100d,形成胚胎,后者分化出第一叶、第一根和茎端,发育为幼孢子体。配子体边缘分布有单细胞毛状体,配子体腹面分布有单列多细胞的毛状体,以中肋处最多,围绕并保护胚胎和幼孢子体。本属3个种的配子体和幼孢子体,在孢子体积、萌发时间、丝状体和成熟配子体特征以及性器产生时间等方面存在差异。土培条件下的配子体发育不同步,即配子体分批发育,原因为配子体的营养繁殖或孢子萌发不整齐。

The development of the gametophyte and juvenile sporophyte are important in the systematics of fern groups, yet have been seldom studied in the genus Phymatopteris. Three species of Phymatopteris are described and compared in the present paper. It was established that spores were monolete, germination was Vittaria-type, and prothallial development was Drynaria-type. Germ filaments developed 2-6 ceils, and mature prothalli were cordate with prominent cushions in the middle of two wings. Prothalli were usually bisexual. Antheridia were produced 48- 55 days after sowing, and archegonia formed 15-18 days after the production of antheridia. Embryos began to devel- op in the cushion of the gametophyte 80-100 days after sowing. Spherical embryos differentiated into the first leaf, the first root, and shoot apex, and then into the juvenile sporophyte. Unicellular hairs appeared on the margin of prothalli and multicellular tmiseriate trichomes developed on the dorsal surface of prothalli, especially in the cush- ion, to surround and protect the embryo and juvenile sporophyte. Differences in size of spores, germination time, characteristics of the filaments and adult prothallus, and time of gametangia formation were documented among the three species. Gametophytes in soil medium usually grew asynchronously, which may have been caused by vegetative generation or asynchronous germination of spores.