文章摘要
谢嗣光.大瓶螺胚胎发育的初步观察[J].水产学报,1994,18(1):39~44
大瓶螺胚胎发育的初步观察
A PRELIMINARY OBSERVATION ON THE EMBRYONIC DEVELOPMENT OF AMPULLARIA GIC.AS
投稿时间:1992-12-16  修订日期:1993-01-01
DOI:
中文关键词: 胚胎发育  大瓶螺
英文关键词: embryonic development  Ampullaria gigas
基金项目:
作者单位
谢嗣光 西南师范大学生物系,重庆 630715 
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中文摘要:
      本文对大瓶螺(Ampullariagigas)的胚胎发育进行了研究.由于大瓶螺卵具钙质卵壳,故采用定时取样,破壳取胚,间断观察的方法.在25±1℃气温中,胚胎发育从卵产出母体后至孵化需274小时,长度增长22倍.全过程可分为7个时期:卵裂期、囊胚期、原肠期、担轮幼虫期、面盘幼虫期、幼螺形成期和孵化期.对各期的外部形态特征进行了描述,并绘制了各期形态图,还对卵的结构,各期发育时间及胚胎大小变化作了描述.
英文摘要:
      This paper deals with the embryonic development of A. gigas. Theembryonic development stages were discontinuously observed because of the egg-ca.psure. The mathod was the fixadate collected specimen and the egg-capsurebroken into spieces to draw out the embryo. In atmospheric temperature at 25土10C,the embryonic development took 274 hours and the length of embryo increased22 times. According to the external morphology,whole developmental course of theembryo can be divided into7 periods as follows:1 .Cleavage period In the early period cleavage follows the spiral molluscan pattern.The polar bodies mark the animal pole of the egg?2 .Blastula Period There is no morpholgycially dletinct ,but the blastula cayity cari been sean on the sectjceng epacimen 3 .Gastrula period Gastrula can be divided into the earlier stage,middle stageand last stage,but passed epiboly and invagination. 4 .Trochophore larva period The time is of short duration. The embryo hasapical,metatroch and telotroch. 5. Veliger larva period Nifty-two hours later the embryo has become a veli-ger larva with veliger area. The foot is bilobed, the larval shell has begun to besecreted. The adult tentacle primordia appear. 6. Juvenile snail form period The foot can move, eye primordia appear,theshell covers the body or visceral mass. The time is 60% of the embryonic develop-went. 7 .Hatching Just hatching juvenile snail has two whorl. The larval livercells appear to be red.
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