为了给栉江珧(Atrina pectinata)受精机理提供细胞学依据，利用透射电镜对栉江珧精子的超微结构进行了详细观察。结果显示，栉江珧成熟精子为典型的原生型，包括头部、中段与尾部三部分。头部为卵圆形，由顶体和细胞核组成。顶体纵切面为倒“V”字形，顶体腔内电子密度不均匀，近顶体外膜有一电子密度较高的弧状带，其余部分电子密度较低。核内有高度浓缩的染色质，其中有不规则的电子密度较低的核泡存在。无核后窝，有核前窝和植入窝。中段由2个相互垂直的中心粒及周围5个呈辐射状排列的线粒体组成。线粒体近卵圆形，由内外膜组成。尾部鞭毛由轴丝和质膜组成。结果表明栉江珧精子超微结构与典型的双壳贝类精子结构类似，在一定程度上反映了栉江珧的生殖进化及受精机理。%To provide the cytology basis for the mechanism of Atrina pectinata fertilization, the ultrastructure of spermatozoon in A. pectinata was observed under transmission electron microscopy (TEM). The results showed that the mature spermatozoon of A. pectinata was typical primitive type, composed of 3 parts including head, middle piece and tail. The head is egg-shaped, and it is composed of acrosome and nucleus. The acrosome is upside-down V-shaped. The distribution of acrosomal materials is uneven. There is an arc near the outer acrosomal membrane with much higher electron density than that of other areas. The nucleus is mainly made up of highly enriched chro-matin, but lower electron density irregular structure is also found. Implantation fossa and anterior nuclear fossa can be observed. However, posterior nuclear fossa is absent. The centriolar complex which is comprised of 2 orthogonal centrioles and 5 surrounding oval mitochondria constitute the middle piece of spermatozoon. Mitochondrion, formed by 2 membranes, is almost spherical in shape. Flagellum in tail is constituted by wavy plasma membrane and axoneme. These results showed that the ultrastructure of spermatozoon in A. pectinata is structurally similar to the typical bivalve spermtozoon, and illustrate the fertilization mechanism of A. pectinata to some extent.
展开▼
