绿海龟稚龟性别鉴定及临界温度

Sex Identification and Pivotal Temperature for Sex Determination in Hatchling Green Sea Turtle

通过组织形态学鉴定、羊水和血液中性激素测定等手段,对惠东港口海龟保护区不同恒温下孵化的绿海龟(Chelonia mydas)进行研究,寻求绿海龟稚龟性别鉴定的最佳方法。结果显示,(1)组织形态学,绿海龟性腺切片分皮层和髓质两部分,卵巢的皮层较厚、基质中有大小不一的未成熟卵细胞,髓质中空腔较少;睾丸的皮层较薄,髓质中空腔较多,呈现出显著的被基质包围的髓质索。(2)性激素测定,当雌二醇与睾酮含量之比E2∶T<1.5时,孵出的稚龟为雄性(♂);当E2∶T>1.5时,为雌性(♀)。(3)绿海龟性别决定的临界温度在29.4～29.5℃之间,此时孵出稚龟的性比约为1∶1。本文还讨论了各种不同性别鉴定方法的优劣和时期选择。

Green sea turtle （Chelonia mydas） eggs were incubated at different temperatures. Hatchling sex was determined by the standard histological examination,and sex hormone test in the amniotic fluid and plasma. The histological findings of this study indicated that the testis showed thin cortex and more medullary cavity, and conspicuous medullary cords surrounded by stromal tissue,while the ovary showed thick cortex and less medullary cavity. Different sizes of immature oocytes were observed in the stroma of ovary. The sex hormone test indicated that the ratio of estradiol （ E2 ） and testosterone （ T） could be used to determine the sex： when E2 ∶ T 1. 5,the hatchlings were males （♂ ）; when E2 ∶ T 1. 5,the hatchlings are females （ ♀）. Pivotal temperatures （PT） for sex determination in Sea Turtle Bay of China ranged from 29. 4℃ to 29. 5℃ ,with an approximate 1 ∶ 1 sex ratio.