【摘要】 采用常规石蜡制片技术和环氧树脂半薄切片技术,对银杏的精细胞结构及受精过程进行了研究。结果表明,临近受精前,精原细胞分裂形成两个半球形的精细胞,每个精细胞内含液泡状结构、生毛体和纤维性颗粒体各一个。两精细胞的液泡状结构其位置可同时或分别位于近极面和远极面,这种位置的变动可能是鞭毛摆动导致精细胞的旋转所引起,这说明银杏的精细胞在花粉管内也许即可以旋转运动。在银杏受精前后,珠孔端颈卵器室附近的珠心组织表现出向上隆起、出现受精滴、皱褶等规律性变化,这些现象是判断银杏受精时期的良好形态特征。在银杏受精时带有鞭毛的完整精细胞进入颈卵器,随后鞭毛带及精细胞质遗留于颈卵器口下方、卵细胞上面,仅精核进入卵细胞。进入卵细胞的精核直径约30μm,小于成熟精细胞的精核直径(约40μm)。这些对探讨银杏的系统地位及裸子植物的生殖演化具有一定意义。更多还原

【Abstract】 The structure of the spermtozoid and fertilization process of Ginkgo biloba were studied by light microscopy using paraffin and epoxy resin semi-thin section.It was found that the spermatogenous cell divided to form two semi-spherical sperm cells prior to fertilization.Each sperm cell contained one vacuole-like structure,one blepharoplast and one fibrillogranular body.The two vacuole-like structures from the same spermatogenous cell could be located at the same proximal surface or the same distal surface or the proximal surface and distal surface,respectively.The position change of vacuole-like structure might be caused by the rotation of sperm cells for flagellar movement and indicated that the rotation of the sperm cells could be happen when they were in pollen tube.The nucellus at the micropylar end showed regular changes during fertilization.Fistly,the nucellus protruded upward,then,the fertilization drop appeared,and finally it shrink.These phenomena were good morphological characters to determine the optimal time for fertilization.At the time of fertilization,the integral sperm with flagella entered into the archegonium,and then the sperm cytoplasm and the flagella were left beyond the egg cell,while only the sperm nucleus which was a dark area about 30 μm in diameter entered into the egg cell.The mature sperm nucleus which were about 40 μm might be condensed before it entered into the egg cell.These results have some significance in understanding the phylogeny of Ginkgo biloba and reproductive evolution of gymnosperms.更多还原