青海湖裸鲤性腺发育的组织学研究

A HISTOLOGICAL STUDY OF THE GONAD DEVELOPMENT OF GYMNOCYPRIS PRZEWALSKII PRZEWALSKII

  • 摘要: 采用石蜡组织切片法,对青海湖裸鲤的性腺发育进行组织学研究,系统地描述了各期卵巢和精巢的形态结构、特征及变化。结果表明:(1)青海湖裸鲤性腺的发育可分为六个时期,卵母细胞从第3时相发育到第4时相基本同步。第Ⅳ期末卵巢,第4时相卵母细胞的卵径大小比较整齐,卵径平均值为2.3mm,第4时相卵母细胞占切面上卵数的85%以上,占切片面积的96%以上,第2、3时相卵母细胞已很少;(2)产后卵巢的组织结构逐步由第Ⅵ期回复到第Ⅱ期,再由第Ⅱ期到第Ⅲ期向第Ⅳ期过渡;(3)性成熟个体有68.12%的雌鱼和83.9%的雄鱼以第Ⅳ期性腺越冬,另有21.01%的雌鱼和10.7%的雄鱼以第Ⅲ期性腺越冬,还有10.87%的雌鱼和5.4%的雄鱼以第Ⅱ期性腺越冬。根据青海湖裸鲤各季节性腺发育情况,作者认为青海湖裸鲤已达到性成熟的个体并不是每年都参与繁殖活动,存在生殖间断性。这反映了青海湖裸鲤的繁殖习性对高原寒冷多变气候的适应性。还对卵黄核和核仁在卵黄形成中的作用以及青海湖裸鲤的产卵类型和生殖间断性进行了讨论。

     

    Abstract: The gonadal development of naked carp,Gymnocypris przewalskii przewalskii,in the Qinghai Lake was studied by lightmicroscope ,and the characters of the ovary and testis at different stages were described.The fish spawns from early April to late July.The gonadal developments of the fish were divided into 6 stages,and the development of oocytes from Phase Ⅲto Phase Ⅳ was synchronous. In the ovaries at late stage Ⅳ,the sizes of oocytes were uniform and the average diameter was 213mm.The oocytes at Phase Ⅳaccounted for above 85 % of the number of all phases,and above 96 % of the section area.Few oocytes at Phase Ⅱand Ⅲremained in these ovaries. After spawning,the ovaries transferred gradually from Stage Ⅵto Stage Ⅱand Ⅲ,and to Stage Ⅳ.The mature individuals wintered,with 68.12%females and 83.9% males having gonads at Stage Ⅳ,21.01% females and 10.7% males at Stage Ⅲ,and 10.87%females and 5.4% males at Stage Ⅱ.According to the observations on the seasonal changes of the gonads,it is believed that the mature individuals do not spawn every year and there is an interval between spwanings.This implies acclimatization to the cold and changeful climate of the tableland. Besides ,the role of yolk nucleus and nucleoli in the vitellogenesis,the spawning type and the spawning interval were discussed.

     

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