黄颡鱼受精早期精子入卵扫描电镜观察

用扫描电镜对黄颡鱼(Pseudobagrus fulvidraco)成熟精、卵及授精早期精子入卵过程进行了观察。成熟精子为鞭毛型形态,全长为11·2～12·4μm,头部直径1·1～1·3μm,鞭毛长10·0～11·3μm。成熟的黄颡鱼卵呈圆形,具单一受精孔,卵膜上以受精孔为中心分布有无数辐射状沟嵴。授精前,受精孔暴露在外面;授精2s时,受精孔被纤维状物质覆盖,之后大量精子很快黏附在覆盖物上;至授精10s,漏斗状受精孔又暴露出来。黄颡鱼在授精10s～1min内完成精子入卵过程,可观察到几乎所有样品的精孔区出现一圈环状隆起。大量精子处于隆起外侧,只有少数越过隆起到达受精孔前庭。授精1·5min,精孔区的隆起变成两圈,精子鞭毛解体。授精3min,可见迟到的精子被挡在外面。授精5min,精孔区的精子头部解体,受精孔几乎被分泌物覆盖,受精塞清晰可见。至授精20min,精子几乎全部解体。讨论了精子入卵的动力作用、精卵识别和单精受精机制。     

怀头鲇成熟卵膜表面扫描电镜观察

The surface ultrastructure of mature egg chorion of the tamed northern sheatfish Silurus soldatovi in Hei- longjiang river was investigated by scanning electron microscopy. The outermost layer was composed of a thin lamella of a jelly coat. The surface of ielly coat was characterized by overlapping net-like fibrillar lamellae, many clefts with bridges and pores. The pore canals were 0.25 μm in diameter. The pore density was about 0.7 - 1.0/μm^-2. The pores on the surface of jelly coart were distributed uniformly. Mature eggs of sheatfish possessed a funnel-shaped micropyle in the animal polar region. The micropylar region was about 0.04 mm^2 area in diameter with 3 - 8 ridges in radial arrangement. Fertilized eggs in which jelly coats were removed mechanically presented no adhesiveness and exhibited inlays of irregular granules on their surface [Acta Zoologica Sinica 51 （5）： 940-946, 2005].