扁平钳蛤性腺发育的组织学研究

Histological Study on the Development of Gonad of Isognomon ephippium

通过石蜡切片对扁平钳蛤进行性腺发育组织学观察,结果表明,扁平钳蛤雌雄性腺的发育都可分为增殖期、生长期、成熟期、排放期和休止期5个时期。增殖期为滤泡形成期,出现了精原细胞和卵原细胞,贴近滤泡壁分布;在生长期,性腺面积、滤泡数目和生殖细胞数目都明显增大,卵母细胞和精母细胞形成;成熟期雌性滤泡内充满卵细胞,其生发泡透亮,核仁清晰可见,雄性滤泡内充满着蓝紫色的精子,精子尾部聚集在滤泡中央,呈鲜红色;排放期滤泡破损,卵细胞和精子排放,性腺面积减小;休止期滤泡腔萎缩,基本无生殖细胞残留。扁平钳蛤生殖周期为一年,5—6月处于性腺发育增殖期;7—10月性腺进入繁殖期,包括生长期、成熟期和排放期;11月进入休止期;其他月份性腺基本不发育。

Isognomon ephippium,with special lurid pearl layer,is a potential aquaculture breed tocultivate special color special pearl. The historical identification of gonad development and reproductivecycle was important for breeding and pearl cultivation in I. ephippium. The development of gonad in I.ephippium was analyzed by histological sections technology. The data indicated that the development ofboth male and female gonads of I. ephippium was devided into the proliferation stage,increasing stage,maturation stage,breeding stage and suspensive stage,with specific characteristics of gonads and germcells. In the proliferation stage,oogonium and spermatogonium were produced in new follicles. Inincreasing stage,the area of the gonads,the number of follicles and germ cells were increased obviously.Massive oocytes and spermatocytes existed in follicles. In maturation stage,the follicles were filled withoocytes,which had bright germinal vesicle,clear nucleolus,and sperms with red tails. In breedingstage,mature germ cells were released from damaged follicles. In suspensive stage,follicles wereshrinked and no germ cells were found. The reproductive cycle of I. ephippium was one year,includingproliferation stage from May to June,increasing stage from July to August,maturation stage from August to September,breeding stage from September to October,suspensive stage from October toNovember. Most gonads did not grow from December to next April.