大竹蛏胚胎发生及稚贝发育基本特征

在人工培育条件下,对大竹蛏(Solen grandis)胚胎发生及稚贝发育进行显微观察,探究大竹蛏胚胎及幼虫发育规律。结果表明,大竹蛏胚胎及幼虫发育过程为:受精卵、卵裂、囊胚期、原肠期、担轮幼虫、D形幼虫、稚贝。在日平均水温为22.4℃时,受精后20～24 h发育成D形幼虫,5～7 d变态为稚贝,38 d稚贝已具备成贝形态,壳长壳高比为2.60。从受精卵到附着所需积温为3 088.79～5 005.19℃.h。稚贝先形成出水管,后形成进水管,最终形成"一管双孔"。壳长与壳高关系式为y=150.37e0.002 7 x,x为壳高(μm),y为壳长(μm),R2=0.985 5,P0.01;壳长与日龄关系式为y=143.38e0.091 6 x,x为日龄(d),y为壳长(μm),R2=0.979 5,P0.01;壳高与日龄关系式为y=33.979 x-15.450,x为日龄(d),y为壳高(μm),R2=0.987 3,P0.01。

Basic Characteristics of Embryogenesis and Juvenile Development of Solen grandis

Under the artificial breeding conditions,the embryogenesis and juvenile development of Solen grandis were observed by light microscopy.The results indicated that the embryonic and larval development of S.grandis included the following stages: zygote,embryo cleavage,blastula,gastrula,trochosphere,d-larvae,and finally juvenile.After 20-24 hours of fertilization,D-larvae appeared at the average daily water temperature of 22.4℃.It took 5-7 days to develop to juvenile,and the juvenile became the adult shellfish after 38 days when the shell length-width ratio was 2.60.The accumulated temperature from zygote to attachment was 3 088.79-5 005.19℃·h.After juvenile developed outlet pipe,its intake pipe appeared,and at last the two pipes transformed into one pipe with diplopore.The regression equation of shell length and shell height was y=150.37e0.002 7x,x: shell height(μm),y: shell length(μm),R2=0.985 5,P<0.01.The regression equation of shell length and day old was y=143.38e0.091 6x,x: day old(d),y: shell length(μm),R2=0.979 5,P<0.01.The regression equation of shell height and day old was y=33.979 x-15.450,x: day old(d),y: shell height(μm),R2=0.987 3,P<0.01.