秦岭北坡中国林蛙精巢显微结构的年周期变化

Annual Variation of the Testicular Microstructure of Rana chensinensis in the North Slope of Qinling Mountains

用光镜观察了秦岭北坡中国林蛙(Ranachensinensis)精巢显微结构的年周期变化,结合精巢系数的变化探讨其生殖规律。结果显示,秦岭北坡中国林蛙的生精周期属于非连续型。精巢系数的变化与精子发生的活动周期相一致。精子发生从每年5月开始,翌年4月结束,历时1年。生精周期可划分为5个时期。Ⅰ期,精原细胞增殖期,5～7月,精巢系数最小,精原细胞进行有丝分裂;Ⅱ期,精母细胞成熟分裂期,8～9月,精巢系数最大,精原细胞、精母细胞和精子细胞在生精小管内共存;Ⅲ期,精子形成期,9～1 0月,精子细胞变态形成精子;Ⅳ期,成熟精子贮存越冬期,1 1月至翌年2月,成熟精子贮存在生精小管中;V期,精子排放期,翌年3～5月,精巢系数显著下降,成熟精子从生精小管脱离,通过输精管道排出体外。

Combined with the variations of testis somatic index, the testicular microstructure of Rana chensinensis in the north slope of Qinling Mountains was observed using light microscopy and during the annual reproductive cycle, to investigate its reproductive pattern. The spermatogenetic cycle of the frog showed a discontinuous type. The seasonal variation of testis somatic index was well consistent with the spermatogenetic cycle. The spermatogenesis in R. chensinensis started in May and ended in April next year. It took one year from spermatogonial proliferation to spermiation. The spermatogenetic cycle of the frog comprised five stages with significant features. In stage Ⅰ from May to July, testis somatic index was in minimum and spermatogonia actively divided, while other spermatogenic cells did not form. In stage Ⅱ from August to September, testis somatic index was in maximum, and many spermatogonia, spermatocytes and spermatids were observed in seminiferous tubules. In stage Ⅲ from September to October, spermatids were transformed to spermatozoa. In stage Ⅳ from November to next February, mature spermatozoa were observed to store in seminiferous tubules. In stage Ⅴ from next March to May, the testis somatic index appeared significantly declined, mature spermatozoa were released from Sertoli cells into the tubule lumen, and thereafter were evacuated from the testis.