马氏珠母贝雌雄同体和自体受精的研究

STUDY ON HERMAPHRODITES AND SELF-FERTILIZATION OF THE PEARL OYSTER PINCTADA MARTENSII

对马氏珠母贝(Pinctada martensiiDunker)成体的性腺进行外观和切片观察,可把马氏珠母贝雌雄同体的个体分为2种类型,其中A类型可以从性腺外观特征上辨别,而B类型需性腺穿刺或组织切片来确认。对试验群体的性腺的类型进行的初步统计表明,雌雄同体个体比例A类型为4.6%,B类型为3.4%,其中雌雄生殖细胞均接近成熟的个体分别约为1.8%和2.1%。通过解剖、0.07‰的氨海水处理,对雌雄同体个体的自体授精及其早期胚胎发育进行了研究,发现自体授精的受精率低于异体授精,同时在发育过程中有较多的卵裂球解体,但仍有部分胚胎可以发育成D型幼虫。

The pearl oyster Pinctada martensii Dunker is the main species in Southern China Sea for commercial pearl production in Leizhou Peninsula and other Beibuwan Gulf regions. Observation on gonad of pearl oyster P. martensii with naked-eyes and sectioning the gonad, the hermaphrodite adults could be classified as two types：type A could be discriminated by observing the gonad and the affirmation of type B should puncture or section the gonad. The primary statistic results showed that the percentage of type A individual was 4.6% and type B was 3.4% in the specimen group, in which percentage of specimens reaching the bisexual maturation were 1.8% and 2.4% respectively. The self-fertilization and early embryonic development of these 2 types of hermaphrodites were studied by artificial dissecting-insemination in the seawater containing 0.07‰ ammonia. Observations on the early embryonic development indicated that self-fertilizing rate were much lower than those between dioecious individuals and many embryos were broken during developing stage while some embryos could develop to D-shaped larvae nonetheless.