怀头鲇胚胎发育过程卵膜形态结构变化及对孵化影响

采用扫描电镜和光学解剖镜,对黑龙江水域怀头鲇(Silirus soldatovi)成熟卵膜层次构造和受精卵胚胎发育过程中卵膜形态结构变化进行观察,并比较未脱黏和人工脱黏卵受精卵膜的表面超微结构变化.结果显示,受精卵膜的胶膜表面由一层薄而致密的物质组成,上有微孔构造.未脱黏受精卵膜表面胶膜光滑致密,多孔隙,内有小梁相连,随胚胎发育逐渐膨胀、展开、变薄,破膜期自然脱落.人工脱黏几乎全部脱去鱼卵的胶膜层,从而使卵失去黏性.脱去胶膜层的受精卵膜表面由不规则的颗粒状结构紧密嵌合而成,表面粗糙,胚胎发育过程中颗粒形状变化不大,但颗粒层逐渐变薄而且疏松,直至胚胎破膜而出:胚胎发育后期颗粒层有过早脱落和破洞出现.同时对活体鱼卵进行连续比较观察,讨论了卵膜结构及动态变化与孵化效果的关系.

The Change of Fertilization Egg Envelope and Its Effect on Embryo Hatching in Northern Sheatfish

The membrane morphological change during embryonic development of Northern Sheatfish (Silirus soldatovi) in Heilongjiang river was observed by scanning electron microscopy and optical dissecting microscopy. The egg surface structure of the demersal and adhesive eggs before and after artificial debonding was also observed. The results showed that the surface of fertilized egg envelope was composed of a layer of thin and dense material with porous structures. The jelly coat on viscous fertilized egg envelope surface was smooth and dense, with many holes connected by trabecular connection (desmosome). With embryonic development jelly coat gradually expanded, unfolded, thinned and, finally naturally shed at the rupture envelope period. Artificial debonding almost took off all jelly coat and the egg lost its adhesivity. The egg envelope surface without jelly coat was coarse and composed of irregular particles and the chain structure around the particles. The structure showed little change during the embryonic development until the embryo hatching out of the envelope. However, the particles gradually lost and ruptured in late embryonic development. The fertilized egg vivisection was also conducted and the relationship between the structure and change of egg envelope and its function was discussed.