长吻鱼危的胚胎发育过程观察OA

To elucidate the sequential characteristics and morphological changes during embryonic development of Leiocassis longirostris,the embryonic development process was systematically observed under conditions of 25℃water temperature and gentle water flow.The results showed that fertilized eggs hatched into newly-hatched larvae after 50 h 15 min.The embryonic development process sequentially underwent seven stages:blastodisc stage,cleavage stage,blastula stage,gastrula stage,neurula stage,organogenesis stage,and hatching stage.The main morphological features of each stage were as follows:a translucent blastodisc formed during the blastodisc stage;the embryo appeared mulberry-shaped during the cleavage stage;the animal pole protruded prominently and then gradually flattened during the blastula stage;the germ layers progressively enveloped the yolk during the gastrula stage;the blastopore closed and the embryonic ring disappeared during the neurula stage;eye buds differentiated and the tail bud formed with rhythmic twitching during the organogenesis stage;during the hatching stage,the tail broke through the membrane first,and the embryo eventually completely emerged through continuous body move-ments.This study provides a theoretical basis for optimizing artificial reproduction techniques and resource conser-vation.