池蝶蚌胚胎发育与繁殖季节性腺的观察

Embryonic Development and Breading-season Gonad in Hyriopsis schlegeli

以池蝶蚌（Hyriopsis schlegeli）育儿囊中单细胞胚胎为材料，通过连续观察、人工体外培养等方法，对繁殖季节池蝶蚌的生殖腺特性、生殖细胞形态、胚胎发育过程等进行了观察。结果表明，年满4冬龄池蝶蚌卵巢的相对怀卵量为（2．25±1．09）×10^3粒/g，绝对怀卵量为1．93×10^4～1．03×10^5粒；性腺指数为24．09％±0．33％；在体外用自制培养液培养的胚胎，部分能正常分裂发育至桑椹期，其胚胎发育过程经历了4个时期，即卵裂期、囊胚期、原肠期、钩介幼虫期。在18～23℃的水温下，胚胎发育历时约12d；胚胎发育的最适水温为20～30~C。此外，通过池蝶蚌外鳃的特征可初步判断胚胎发育的时期。研究结果可为池蝶蚌人工繁殖、新品种培育及种质资源保护等提供理论依据。

The characteristics of gonadal structure, gamete （sperm and egg） morphology and embryonic development of Hyriopsis schlegeli were studied by continuous observation and in vitro culture. The results showed that the absolute fecundity was 1.93×10^4 - 1.03×10^5 eggs and the relative fecundity was （2.25±1.09）×10^3 eggs/g. The gonad index （GI） was 24.09%±0.33%. The embryo cultured in vitro could develop successfully to blastocyst in nutrient solution prepared by ourselves. Embryonic development and process were described. The embryo development of H. schlegeli was divided into four stages： cleavage, blastocyst, gastrulae and glochidia, The embryonic development took 12 days when the water temperature ranged between 18 -23℃. The optimum temperature range for the embryonic development was 20 - 30℃. As observed, the glochidia of this species were hooked and there were relations between embryonic development stages and the outer gill characters of the female. Our results will provide valuable data for artificial reproduction, germplasm resource conservation and breeding in freshwater pearl mussel.