锦江翘嘴鲌性腺发育的组织学研究

Histological observation of gonadal development of topmouth culter Culter alburnus in Jinjiang River

为研究锦江翘嘴鲌Culter alburnus性腺发育特征,通过生物学解剖和常规石蜡组织切片观察,对沅江支流锦江翘嘴鲌性腺及生殖细胞发育的周年变化特征进行了研究。结果表明:精巢属于小叶型结构,其发育分为6个时期,精母细胞发育分为5个阶段,即精原细胞、初级精母细胞、次级精母细胞、精子细胞及精子;雌鱼性腺发育分为6个时期,卵母细胞发育分为6个时相,第Ⅰ时相核仁出现,数量在第Ⅱ和第Ⅲ时相逐渐增多,第Ⅱ时相出现单层滤泡膜和卵黄核,第Ⅲ时相卵黄核消失,滤泡膜分化出两层,液泡和放射带出现,晚期卵黄颗粒可见,第Ⅳ时相卵黄大量积累,液泡被挤压到细胞质外缘,晚期核偏位,第Ⅴ时相细胞质中充满卵黄颗粒,并融合成块状,细胞核消失,卵膜内缘有皮质泡明显可见,第Ⅵ时相未排出的成熟卵以颗粒细胞形式被分解吸收,在第Ⅱ至Ⅵ时相的卵母细胞中都存在退化细胞。研究表明,卵母细胞和精母细胞的发育均表现出不同步特征,本研究结果可为锦江翘嘴鲌的资源保护和人工繁育提供数据参考。

Morphological and histological development of gonad and germ cells were annually observed in topmouth culter Culter alburnus with body weight of(22.2-2587.5)g by paraffin section technique and H.E staining method. The topmouth culter had testis made up of lobules with spermatogenic cells in cysts, and the development of testis was divided into 6 stages. Spermatogenesis experienced 5 phases: spermatogonia, primary spermatocytes, secondary spermatocytes, spermatid, and spermatozoa, and the developments of ovary were divided into 6 stages, and oogenesis experienced 6 phases. The nucleoli were observed at phase Ⅰ, and increased in number at following phase Ⅱ and Ⅲ. The follicle membrane and yolk nuclei were found at phase Ⅱ, yolk nuclei disappeared at phase Ⅲ, and yolk granules appeared at the late phase Ⅲ, at the same phase follicle membrane differentiated into two layers, the vacuole was formed and changed from one layer to a multilayer, with a light red flocculent area in each of it. The zona radiata were presented at the surface of egg membrane from phase Ⅲ to Ⅴ, yolk granules accumulated at phase Ⅳ, vacuoles were squeezed at the outer edge of cytoplasm, and the nuclei deviated to the edge at late phase Ⅳ. The oocytes were filled with yolk granules at phase Ⅴ, being fused into pieces, and nuclei disappeared, and cortical alveolus became evident. The unspawned ova were broken down and absorbed at phase Ⅵ, and lifted a lot of postovulatory follicles in the oocyte. There existed degenerated cells in the oocyte from phase Ⅱ to Ⅵ, with asynchronous developmental oocytes and spermatocytes. The findings might be used to provide basic data for resource conservation and artificial breeding of topmouth culter in Jinjiang River.