金粉蕨配子体发育及其无配子生殖的研究

采用光学显微镜和半薄切片技术对金粉蕨(Onychium siliculosum(Desv.)C.Chr.)的配子体发育及其无配子生殖进行了研究。金粉蕨孢子黄褐色,具三裂缝,孢子萌发时先产生假根,然后长出原叶体细胞,萌发类型为书带蕨型。原叶体细胞经丝状体、片状体发育为原叶体,发育类型为水蕨型。金粉蕨配子体分枝发达,成熟配子体呈丛状。多次培养表明金粉蕨只能产生精子器,不能产生颈卵器,为专性无配子生殖。半薄切片观察表明配子体生长点下方的细胞经分裂产生一群小型细胞,由它们发育为无配子生殖胚。小型细胞先分化出无性胚芽,再分化出胚根。胚芽与胚根,胚与配子体之间由分化出的导管连接。

Gametophytic Development and Apogamy of the Fern Onychium siliculosum(Desv.) C. Chr.

The gametophytic development and apogamy of the fern Onychium siliculosum(Desv.) C. Chr. were observed by microscope and semithin section technique. The results exhibited that the spores are tawny, tetrahedral, and trilete. During the period of germination a rhizoid was produced firstly, then the prothallial initial cells. The germination was of the Vittaria-type. The prothallial cells, after experiencing the stages of filament and thallus, developed into prothallium. The pattern of the prothallial development was Ceratopteris-type. The filaments were rich in branches and they formed cluster prothallia. Antheridia were generated on the prothallia, but no archegonia were formed through repeated experiments. This species belonged to obligate apogamy. The observation of semithin section showed that the apogamous embryo is caused by the divisions of a group of small cells, which originated from the gametophytic cells behind the apical notch of the prothallium. The apogamous bud was differentiated first from the small cells, and then the root. The apogamous bud and the embryo root were connected by the differentiated vessels which also connected the gametphyte and the sporephyte.