摘要
选取性成熟的赤眼鳟(Squaliobarbus curriculus)亲鱼,体质量800~2 300 g,经人工催产后,在27℃条件下进行干法人工授精。取成熟卵及相遇后不同时间段的精卵用扫描电镜对赤眼鳟成熟精、卵及精子入卵早期过程进行观察。结果显示,赤眼鳟成熟精子为鞭毛型形态,全长19.6~22.4μm。头部直径约1.65μm,鞭毛长17.8~20.6μm,头径与鞭毛长度之比为(1∶9.89)^(1∶11.4)。赤眼鳟成熟卵呈圆形,具单一受精孔。卵膜厚度约为2.78μm,卵膜表面平滑光洁;无明显的沟或嵴,卵膜表面可见均匀分布有很多孔小管,直径约0.14μm。在动物极具一漏斗状凹陷卵膜孔,直径12.46~14.10μm,其底部为圆环状的受精孔,受精孔的周边平滑,向四周呈辐射状隆起,外孔径约5.21μm,内孔径约2.71μm。在27℃时,赤眼鳟精子18 s内可完成入卵过程;约60 s后受精孔外的精子全部解体。通过对精子、卵及精孔管的测量和扫描电镜观察,确定赤眼鳟受精方式为单精受精。
The mature eggs, spermatozoa of Squaliobarbus curriculus and the early fertilization have been observed under scanning electron microscope（SEM）. The spermatozoon consists of two parts： the head and the tail. The total length of the spermatozoon is 19.6 to 22.4 μm. Diameter of the spermatozoon head is 1.65μm, and the length of the tail is 17.8 to 20.6μm. The mature egg of Squaliobarbus curriculus is elliptic and has a single micropyle on the animal pole. The micropyle is funneled with an annular fertilized aperture on the bottom. The diameter of the micropyle is 12.46 to 14.10μm; the thickness of egg membrane is 2.78μm. The egg membrane is watched smooth under the lower magnification of SEM;under the high magnification of SEM, there are no fossae and ridges found but many pore canals distributing on the egg membrane homogeneously. The diameter of the pore canals is 0.14μm. Around the smooth fertilized aperture, there are some radiating bulking. The inner diameter of the fertilized aperture is 2.71μm, and the outer is 5.21μm.
The process of spermatozoa penetrating eggs is observed at 27℃ and described as follows：2 to 4 second after spermatozoa penetrating eggs, the spermatozoa arrive the certain area of egg near the micropyle, the head of the spermatozoon is opposite to the micropyle. From 8 to 18 second, there are many spermatozoa around the micropyle, one of them begin entering the fertilized aperture and left the tail out of it. During this period, there isn＇ t any fiberized embolus blocking the micropyle. Then, along with the cortical reaction caused by fertilization, the micropyle is gradually blocked by many cortical granules. At this time, the process of spermatozoon penetrating egg is finished. From 20 to 28 second, the micropyle is blocked by fiberized embolus; the fertilized aperture is closed too. From 30 to 60 second, the fiberized embolus in the miropyle is becoming more and more, the spermatozoa outside the micropyle can not enter the egg, and loose the capability of voluntary movement. In 40 second, the disorganized spermatozoa can be seen under the SEM; in 55 second, the micropyle is blocked with some large embolus, the spermatozoa are disorganized completely.
Above all, these conclusions are drawn; Mechanism of Squaliobarbus curriculus＇s fertilization follows monospermy, Only one spermatozoon can get through the micropyle canal of one egg and enter it, while the others will be disorganized automatically. In 18 second after a spermatozoon goes into an egg, the embolus will be formed to prevent the other sperms getting into the egg, which insures the mechanism of monospermy.
出处
《中国水产科学》
CAS
CSCD
北大核心
2006年第5期740-744,共5页
Journal of Fishery Sciences of China
基金
国家"十五"科技攻关计划(2004BA508B18)
广东省科技计划项目重大专项(2005A20105001)
广东省科技攻关项目(2005B20301003)
关键词
赤眼鳟
受精
扫描电镜
Squaliobarbus curriculus
fertilization
scanning electron microscope
