中华绒螯蟹卵黄发生期卵母细胞和卵泡细胞超微结构观察

Ultrastructure of oocytes and follicular cells during vitellogenesis of Eriocheir sinensis

通过透射电镜技术观察了中华绒螯蟹第二次卵巢发育过程中卵巢的超微结构变化。结果表明:(1)中华绒螯蟹第二次卵巢发育过程中卵黄发生期可分为初期和后期;(2)卵黄发生初期(雌蟹第一次排卵后的16d内),卵黄生成以卵母细胞内源性合成为主,此时卵母细胞胞质中存在大量内质网囊泡、高尔基体和线粒体,这些细胞器参与胞内卵黄物质的合成。内源性合成后期,卵母细胞膜形态多样,呈现触手状、波浪状和断裂状,为外源合成期做准备。此期卵泡细胞还未向卵母细胞靠近,两类细胞间存在着由淋巴细胞吐出的絮状物;(3)卵黄发生后期,首先为卵泡细胞与卵母细胞的结合阶段(排卵后16-21d),此后,卵泡细胞胞质中含有大量内质网囊泡、卵黄颗粒和脂滴,卵母细胞与卵泡细胞膜变为链珠状便于物质交换,卵母细胞的卵黄合成能力减少,转由卵泡细胞进行外源性物质吸收和卵黄物质合成(21-36d);(4)卵黄发生结束后,双层卵膜形成,卵黄体和脂肪滴均匀分布在卵母细胞胞质中。

The study was conducted to investigate the ultrastructure of the Eriocheir sinensis H. Milne Edwards ovary during the secondary ovary development by transmission microscopy. The results showed that： （ 1 ） Vitellogenesis in the Eriocheir sinensis H. Milne Edwards can be divided into two stages： primary stage and secondary stage. （2） In primary stage （in 1 -16 days after the first spawning）, vitellogenesis was formed mainly by intro-oocytic yolk formation. Many vesicles of the endoplamic reticulum, Golgi complex and mitochondria were present in the cytoplasm of oocytes, which involved in yolk formation. In the late primary vitellogenesis, the membrane of oocytes turned into various shapes such as hand, wave or brokenliked, which were prepared for extra-oocytic yolk formation. The follicular cells were far away from oocytes. There were lots of flocculent dense bodies from lymphocytes distributed between the follicular cells and oocytes. （3） In secondary vitellogenesis, first, follicular cells combined with oocytes（in 16 -21 days after the first spawing ）, then many vesicles of the endoplamic reticulum, yolk and lipid droplets were present in the cytoplasm of follicular cells. A ball and chain structure formed in the interface of oocytes and follicular cells, so that large amount of material of the follicular cell could be directly taken into the oocytes. The ability of yolk formation of oocytes decreased significantly, while the extra-oocytic yolk formed by follicular cells in 21-36 days after the first spawning. （4） Two distinct layers were identified in matured oocyte surface. The matured oocytes were characterized by accumulation with irregular yolk bodies and lipid droplets which were scattered throughout the ooplasm.