东海三疣梭子蟹精子发生及精荚形成

Spermatogenesis and spermatophore formation of swimming crab(Portunus trituberculatus Miers,1876)in East China Sea

为探究东海三疣梭子蟹(Portunus trituberculatus Miers,1876)雄性群体的性腺发育规律,通过定期采样,运用形态学、组织学方法对东海三疣梭子蟹精子发生及精荚形成过程进行了研究,并结合精小叶生殖节段法对处于不同发育阶段的精巢进行了定性分析。结果表明,三疣梭子蟹精巢属于叶型,由精小叶和精小管组成的叶状管交织而成。精子发生过程与其他高等短尾派蟹类相似,精子成熟后即进入精小管中。输精管可能起源于精小管。三疣梭子蟹精巢和输精管的发育存在一定的年际变化。4-5月份,精巢小叶内精原细胞占优势,输精管内精荚零星分布;6-7月份,精母细胞与精细胞比例增加;8月份精母细胞为主。到了9月份,整个精巢完全被精细胞等发育程度较高的精小叶所占据,输精管内充满精液和精荚,为即将到来的交配季节做好准备。三疣梭子蟹交配活动主要集中在10月份。12月份精巢精小叶中出现游离精子。此后,精巢逐渐退化(1-3月),但输精管中一直储存着精液和精荚。三疣梭子蟹精荚形成过程始于前输精细管,精荚膜两层,分别由来自前输精细管分泌的第一种不定物质和其中、后端分泌的第二种不定物质。精荚内的基质可能直接源于精巢的精小叶部分。输精管中的强嗜酸性颗粒与第二种不定物质有融合作用,使输精管中贮存的精荚膜嗜酸性。

In order to explore the spermatogenesis and spermatophore formation of the swimming crab（Portunus trituberculatus）in East China Sea,by the morphological and histological method and sampling monthly we did some research on the testes and vas deferens of all possible sizes of the crabs which to the same year-class.Moreover,using the ratio of the lobular mature sections method,we also did quantitative analysis on testis in different phases of the development.The results showed that the testis of P.trituberculatus were lobular style and consisted of some convoluted lobes made up of numerous lobules and some seminiferous ducts.The spermatogenesis was typical as other brachyuran and when spermiogenesis completed the sperms soon moved into the seminiferous ducts.The vas deferens might origin from seminiferous ducts.The testes and vas deferens of P.trituberculatus showed conspicuous seasonal variation.The spermatogona predominated in testicular lobule and few spermatophore existed in the vas deferens in Apr-May.Then the radio of the spermatocytes and spermatids increased in Jun-Jul and in August,spermatocytes were dominating.Up to September,the testicular lobules were occupied by the spermatids which showed the testis had developed in a relatively high stage completely and the vas deferens were full of semen and spermatophpores,preparing for the coming copulation season.The mating activity of P.trituberculatus in copulation season（Oct-Nov）mainly occurred October.In December, the testicular lobule of P.trituberculatus appeared dissociated sperms and from then on the whole testis began to degrade gradually（Jun-Mar）,but the vas deferens still contained lots of semen and spermatophores.The formation of spermatophore of P.trituberculatus started in proximal region of the anterior vas deferens and the spermatophore had two pellicles from the two amorphous matters which were secreted by the corresponding parts of the vas deferens respectively.The matrix of the spermatophore might directly origin from the testicular lobular.The second amorphous mattercould syncretize the granules of the acidophilic seminal granules,which maked the pellicle of spermatophore stored in the middle vas deferens acidophily.