番红砗磲幼虫的生长

番红砗磲Tridacna crocea Lamarck由D形幼虫发育至幼苗(第26天),壳长净生长106.62μm,壳高净生长104.41μm。其生长过程可分为三个时期:面盘期幼虫生长快,壳高的增长大于壳长的增长;变态期幼虫生长平缓,壳长与壳高的增长接近均衡;两者之间的足面盘过渡期幼虫生长出现两个停滞期。壳长与壳高的关系可以H=0.99998L-21.81275表示,它们分别与铰合部长度的变化有联系。壳长/壳高和(1/2)壳高/铰合部长度两个比率呈现一定的规律性,并可预测幼虫足的发生。

LARVAL GROWTH OF GIANT CLAMS Tridacna crocea Lamarck

As the larvae of giant clams Tridacna crocea Lamarck grew from D-larva to juvenile of day-26, the total increasements of shell length and height were 106.62 and 104.41um respectively.The growing process can be divided into three periods. 1) Veliger period, during which the larvae grew fast, shell height increased faster than shell length;2) Veliger-pedo-metamorphosis period , in which the growth of the larvae appeared mainly as two growth-retardation periods;3) Metamorphosis period, during which larvae grew slightly slow, shell length grew in a speed almost as that of shell height. The relationship between length and height of larval shell can be described by a linear regression equation as follows. H = 0.99998L-21.81275; and the changes of them were respectively related to the changes of straight-hinge-length. The ratios of Length/Height, and of Half-height/Straight-hinge length regularly happened, so that the occurence of larval foot could be portended.