三角帆蚌胚胎在外鳃育儿囊内形态变化初步研究

A primary study on the morphological changes of embryo of Hyriopsis cumingii in nurturing pouch of outer gill

对三角帆蚌胚胎在其外鳃育儿囊内的形态变化进行了显微观察。结果表明:在水温20℃-23℃时,受精卵发育为膜内钩介幼虫需11 d;受精卵吸水后,卵膜膨胀,在整个发育过程中,其大小无显著变化,但膜内胚胎生长明显;整个发育期分为受精卵、卵裂期、原肠期、膜内钩介幼虫期,经过这4个时期,胚胎最大长度增长了82.8%,生长速度在后期快于前期,并且以原肠期和膜内勾介幼虫期增长速度最快。胚胎发育的不同时期与外鳃特征具相关性。

The morphological changes of embryo of Hyriopsis cumingii in its nurturing pouch of outer gill were examined. It was found that, when the water temperature ranged from 20℃ to 23 ℃, the embryonic development from oosperm to mature glochidia took 11 days. After the oosperm sucked the water, the membrance sweh up and its size varied little, while the embryo bulged distinctly. The embryonic development of Hyriopsis cumingii might be divided into four stages： oosperm, cleavage, gastrulae and glochidia. The length of embryo increased 82.8% during the whole embryonic development. The growth rate of late embryo was higher than that of early embryo. The highest growth rate was observed in gastrulae stage and glochidia stage. There were relations between different stages of the embryonic development and the character of the outer gill of the female.