扇贝精子及卵子的受精生物学特性

采用扫描电子显微镜和普通光学显微镜观察方法,结合全光谱扫描分析方法,对栉孔扇贝和虾夷扇贝的精子及卵子的受精生物学特性进行了详细的观察,包括精卵产出后形态学变化、卵水的特性、精子顶体反应、卵子皮层反应以及精子分级分离组分对卵子的作用5个方面.结果表明,这两种扇贝精卵生物学特性没有本质的区别,扇贝精子排入海水中10min以内,外形没有太大的变化,但30min以后约有1/4的精子出现头部膨大变成圆球形的现象,受精能力明显下降;扇贝卵子产入海水中1h以内受精能力没有变化,但2h以后,约1/3的卵子出现卵裂现象,未见极体的排放,且卵裂多停止在2细胞期,少数达到4细胞期,基本属于均等卵裂,并失去受精能力;滴入卵水中的精子极易发生自溶解体,未解体的精子发生凝集,10min之后卵水中基本检测不到完整的精子,卵水和钙离子载体A23187均能诱导精子发生顶体反应;精子分级分离组分分别为精浆、精子头部和精子尾部,这三部分除了少数精子头部能够附着在卵子表面外,其他都不具备激活卵子的作用.对扇贝精子和卵子的生物学特性的研究将为解释不同种扇贝的精卵相互识别并受精的现象提供基础资料.

Fertilization biology of eggs and sperms in two scallop species, Patinopecten yessoensis and Chlamys farreri

The fertilization biology characteristics of eggs and sperms in two scallop species, Patinopecten yessoensis and Chlamys farreri, including morphological changes of gametes after release, egg water characteristics, sperm acrosome reaction, egg cortical reaction, and the effect of the sperm fractional separation components on the eggs, were observed using electronic microscopy, optical microscopy, and spectrum scanning analysis and insemination. The results showed that there were no significant difference in biological characteristics between P. yessoensis and C. farreri. No obvious appearance changes in the scallop sperms within 10min after release in the seawater. However, 30 minutes later, 25% of the sperms became head-enlarged to near spherical and the fertilization ability was weakened. While the fertilization ability of the scallop eggs did not change within 1 hour after release in the seawater, and about 33% of the eggs became cleaved but without appearance of polar body in two hours. Most egg cleavage were equal cleavage terminated at the 2-cell stage and some at the 4-cell stage, and the fertilization ability of the eggs at this phase were lost. Most sperms dropped into the egg water were autolyzed, and other sperm agglutinated. No intact sperm individual was seen after being transferred into the egg water for 10 minutes. The sperm acrosome reaction was induced by the egg water or calcium ionophone A23187.Although a few sperm heads attached to the surface of the eggs, the components of sperm including seminal plasma, sperm head, and sperm tail, could not activate the eggs. This research on biological characteristics of eggs and sperms in scallop are expected to provide basic data for understanding why sperm and eggs from different species of scallops could recognize each other and fertilize.