中国明对虾(Fenneropenaeus chinensis)外部性征的分化及发育

Differentiation and Development of External Sex Characteristics of Shrimp (Fenneropenaeus chinensis)

中文关键词: 中国明对虾  性别分化  发育  纳精囊  交接器

英文关键词: Fenneropenaeus chinensis  Sexual differentiation  Development  Thelycum  Petasma

中文摘要:

      中国明对虾(Fenneropenaeus chinensis)的性别分化和生殖器官发育是其繁殖生物学的重要部分，也是进行性别调控的基础。经过2年的取样观察，研究了中国明对虾雌性纳精囊和雄性交接器的分化与发育过程。结果显示，早在仔虾后16 d (16 days post-larva, PL16)即开始雌雄分化，此时，雌虾第4与第5对步足间腹甲处的锥突出现明显下陷，而雄虾的没有下陷。PL54时，雌虾纳精囊瓣膜出现，然后继续发育，到PL124时形成纳精囊雏形；雄虾交接器发育较晚，到PL54时，雄虾第1泳足的内肢才出现分化，在PL106基本形成雄性交接器。

英文摘要:

      Fenneropenaeus chinensis is one of the prominent aquaculture shrimp species in China. To better understand its reproductive biology, here we investigated the sexual differentiation and development of the shrimp. The morphological changes of the female thelycum and the male petasma were observed. The larvae of F. chinensis collected from Yellow Sea Fisheries Research Institute (YSFRI) in Aprils of 2012 and 2013 were cultured in a circulating water system. The adult F. chinensis were purchased from aquatic produce market. The samples were fixed in Bouin’s solution for 16–24 h after being anesthetized with seawater saturated with Mg2SO4, and then stored in 70% ethanol at 4℃ for observation of external sexual development. The images were taken by Olympus CX22 LEDRFS1 microscope. It was found that the sexual differentiation of female shrimp started at 16 days post-larva (PL16). A subsidence appeared in the conuli on the ventral plate between the fourth and fifth pairs of pereopods in female shrimp, but no subsidence in the conuli was found in male shrimp. The valves that were components of thelycum appeared at the base of the fourth (anterior valve) and fifth pairs of pereopods (posterior valve) at PL54. At PL112, the form of anterior valve appeared to be similar to “epsilon type”. At PL124, the thelycum began to develop. Compared to the development of thelycum, the growth of petasma of male shrimps was late. The initial differentiation of endopodite on the first pair of pleopods was found at PL54, indicating the formation of male external genitalia. At PL106, petasma appeared to be similar to that of adults. The cannelure became obvious and periphery up folded, but the endopodite on the first pair of pleopods in female remained a willow-leaf shape.