鲫鲤杂种F2精子多态性的研究

本文利用扫描电镜和透射电镜对鲫鲤杂种F2精子的超微结构进行了系统的研究。F2精子由头部、中片和尾部组成，头部前端有液泡，没有顶体。研究发现，F2精子头部大小差别明显，最小的精子头径只有1．32μm，而最大的那个“超级精子”头径约18．39μm，但是绝大部分精子头径在1．85-2．15μm。另外，通过透射电镜还发现了双核精子和双尾精子。结果表明，F2精子中存在着明显的多态性，其中有正常的精子，即单倍体精子；也有异常的精子，包括二倍体精子、四倍体精子甚至更高倍性的精子，还有非整倍体精子。本研究结果为二倍体的精子和二倍体的卵子结合产生四倍体的机制提供了有利的证据。

Studies on the ploymorphic of sperm of F2 hybrids of red crucian carp x common carp]

AThe ultrastructures of the sperm of F2 hybrids of red crucian carp x common carp were studied by using scanning and transmission electron microscope. The sperm of the F2 hybrids consisted of head, mid-piece and tail. There was no acrosome at the anterior end of the nuclears, whereas there was a vesicle. The results revealed that there existed obviously ploymorphic in the sperm of F2 hybrids. In the water-like semen from males of F2 hybrids, different sizes of the head of the sperm including haploid, diploid, tetraploid, and aneuploid sperm were observed. The head diameter of the smallest sperm was only 1.32 microm, but that of the biggest one was about 18.39 microm, and most of them varied from 1.85 to 2.15 microm. The haploid sperm was normal, while the a-neuploid, diploid, tetraploid and multiploid sperm were abnormal. Among the abnormal sperm, there was a super sperm with about 20 tails, whose head volume was much bigger than that of any other sperm. From the results of the transmission electron microscope, 3 sperm with two nucleus and 1 sperm with two tails were found. This study provided an useful evidence for the mechanism that the formation of tetraploid in F3 hybrids was due to the fertilization of the diploid eggs and diploid sperm produced by F2 hybrids.