中国林蛙性腺的发育及温度对其性别分化的影响

Development of Sexual Gland and Influence of Temperature on Sexual Differentiation in Rana chensinensis

为探讨幼蛙性别分化与温度的关系 ,在恒温和变温条件下培养中国林蛙 (Ranachensinensis)受精卵至变态完成。结果表明 :①胚胎发育到 2 4期时生殖嵴开始出现 ,2 5期个别原始生殖细胞 (PGCs)已迁移到生殖嵴中 ,生殖细胞与生殖嵴共同发育成生殖腺 ;②胚胎发育到 3 1期生殖腺出现性别分化 ,卵巢分化初期较易识别 ,而精巢分化不明显 ;③卵巢分化完成于 3 7期 ,精巢分化完成于变态之后 ,两侧生殖腺等大 ;④胚胎发育从 3 0期开始 ,性别分化对温度较为敏感 ,低温利于雌性化 ,高温利于雄性化 ;⑤ 15～ 2 5℃为变温培养时性比发生变化的敏感温度区 ,缓慢升温雄性比例显著增加 。

Under constant and alternating temperature conditions oosperms of Rana chensinensis were cultivated till the completion of metamorphosis.The study was done on the development of sexual gland during the embryo stage,the beginning and ending periods of sexual differentiation and the relationship between temperature and sexual differentiation of Rana chensinensis .The results showed:①In the 24 th period of embryo development,a genital ridge began to appear,and in the 25 th period there had been a few PGCs moved to the genital ridge.PGCs together with the genital ridge developed into a sexual gland.②In the 31 st period of embryo development,the sexual gland began to differentiate;the initial differentiation stage of an ovary was easy to recognize while the differentiation of a testis was not so obvious.③The differentiation of the ovary completed at the 37 th period,while the differentiation of the testis completed after metamorphosis,and the left and the right sides of the sexual glands were the same size.④In the 30 th period of the embryo,sex differentiation began to be impressible to temperature,and lower temperature was favorable for feminization,while higher temperature was favorable for masculinization.⑤In alternating temperature conditions the impressible temperature range for the sex ratio was 15-20℃;slow rise of temperature would increase the male ratio,while slow drop of temperature would increase the female ratio.