泥鳅精子和卵子结构及受精过程的细胞学观察

CYTOLOGICAL STUDIES ON STRUCTURE OF SPERMS AND EGGS OF MISGURNUS ANGUILLICAUDATUS AND THE FERTILIZATION PROCESS

研究旨在探讨泥鳅精子受精时限及为其人工繁殖提供基础资料。采用光镜、电镜技术对泥鳅(Misgurnus anguillicaudatus)精子、卵子和不同时间段的受精卵进行了观察。结果显示:泥鳅精子头部无顶体,主要为核占据,核凹窝较浅,中段具不对称的袖套,尾部轴丝为"9+2"结构,无侧鳍。卵子动物极卵膜仅有一受精孔,受精孔为深凹陷、短孔道型。在20—21℃水温条件下,授精后3s,精子开始穿过精孔管或已经进入卵子;授精后5—8s,形成精子星光;授精后70s,卵子处于第二次减数分裂后期;授精后6—8min,第二极体形成,等待排出;授精后20—25min,雌雄原核融合;授精后25—30min,受精卵进入第一次有丝分裂中期;授精后40—45min,第一次有丝分裂结束,二细胞形成。研究表明:成熟卵子精孔管内口径(2.286±0.364)μm,而精子头部直径与其接近,单精受精;入水后150s内可受精。

This study investigated fertilization of spermatozoa of Misgurnus. anguillicaudatus at different time periods using optical microscope and electron microscope technology methods. The results showed that no acrosome was observed in the head of the sperm, which was mainly occupied by the nuclear. The implantation fossa of the sperms was low, and the mid-piece contained asymmetric sleeve. The flagella without lateral fins were organized as a ＂9＋2＂ microtubular structure by axonemes. There was only one micropyle in shell of egg＇s animal pole, and the micropyle belongs to the type of concave and short channel. Under the water temperature of 20-21, sperm passed micropylar tube and entered ovum at 3s after insemination; sperm star light was observed at 5-8s; the second meiosis of the ovum occurred at 70s after insemination; the second polocyte appeared at 6-8min after insemination. Male and female prnucleus were fused at 20-25min after insemination. Zygote was in metaphase of first mitosis at 25-30min after insemination. The first mitosis finished at 40-45min after insemination, and two cells then formed. The inner diameter of micropylar tube of mature egg was （2.286±0.364） μm, similar like the diameter of sperm head, and the monospermy of M. anguillicaudatus. Eggs of M. anguillicaudatus were fertilizable in 150s after entering to water.