牛蛙性腺发育的研究

本文对牛蛙的性腺发育进行了研究。在湖南地区,雄性牛蛙的性成熟年龄是1年,雌性是1—2年;4月下旬到7月上旬是产卵季节;由于年龄和体重的差异,产卵前卵巢系数为12.6—27.6%,产卵2—5万个;产卵后卵巢系数为2—6%;一年一度产卵一次,属于一次性产卵类型。牛蛙卵细胞在生长发育过程中可以分为卵原细胞期、初级卵泡期、生长卵泡期和成熟卵泡期。雌蛙达到性成熟年龄以后,随着季节的运转,卵巢也按一定的规律发生周期性的变化,而季节的变化对精子的发生影响不大,成熟雄牛蛙在任何季节都有成熟的精子存在,只是数量不同而已。

STUDY ON THE GONADAL DEVELOPMENT OF BULLFROG, Rana catesbeiana

The age for sexual maturity of the male bullfrog has been determined to be one year and that of the female, one or two years, in Hunan.They breed from the late April to the early July. In breeding season, the coefficients of the ovaries are 12.6-27.6% before spawning and 2-6% just after the females deposited their eggs. The mature females spawn only once a year and they generally lay eggs from twenty thousand to fifty thousand respectively. The entire course of oogenesis can be divided into four stages, i.e.oogonium, primary follicles, growing follicles and mature follicles. The structures of the ovaries will change cyclically as the seasons turn and turn about. The influence of the seasonal changes on spermatogenesis isn't apparent. The sperms exist in the testes in any season of the year.