槲蕨配子体形态发育的扫描电镜观察

该研究以水龙骨科(Polypodiaceae)槲蕨(Drynaria roosii Nakaike)为研究对象,在人工培养条件下,采用扫描电镜观察其配子体发育的全过程,以期从三维立体角度揭示槲蕨配子体各发育阶段中的一些精细结构,为进一步补充部分经典形态学理论提供依据。结果显示:(1)槲蕨孢子萌发过程中原叶体母细胞的初生假根存在两条同时生长的现象。(2)槲蕨配子体的假根膨大及分叉现象普遍,且具有2层细胞壁,基部呈圆孔状结构。(3)槲蕨的原叶体腹面及边缘处毛状体非常发达,且乳突状单细胞毛状体和针状单细胞毛状体混生。(4)精子器释放精子时,盖细胞前后呈不同开裂状态。(5)发现精细胞向游动精子转化可能的限制性结构是细胞膜,细胞膜表面附着有碎屑状物质。(6)观察到腹沟细胞的解体过程是从近颈卵器开口处的细胞膜开始逐渐向四周及其后下方扩展。(7)发现了颈壁细胞在排列顺序和数量上都不稳定的畸形颈卵器、体积正常但无法区分雌雄的性器及体积显著增大呈锥形的泡状败育性器。

Observations on the Morphological Gametophyte Development of Drynaria roosii Nakaike by SEM

Under artificial culture conditions, we observed the whole process of gametophyte development of Drynaria roosii Nakaike in Polypodiaceae by scanning electron microscopy in order to reveal some fine structures in different stages of the gametophyte in three dimensions, and provide the evidence for further supplement of classical morphological theory. The results were as follows: (1) two rhizoids of prothallium metrocytes were earliest and simultaneous formed in the process of spore germination. (2) Most rhizoids of the gametophyte of D. roosii were bulging and bifurcate with two cell walls, and the base of the rhizoids was round. (3) The trichomes extensively developed in venter and margin of prothallium, mastoid and acicular single celled trichome mixed together. (4) When the antheridia released sperms, the anterior and posterior dehiscence of the cover cells were different. (5) The cytomembrane which attached clastic materials, might be restrictive structure from the sperm to the antherozoid. (6) The disintegration process of ventral canal cells started from the membrane of archegonium opening. (7) It was found that the abnormal archegonium, sex organ that did not distinguish between male and female and sex organ which were vesicular and abortion.