中国鲎的胚胎发育

Embryonic Development of Tachypleus tridentatus

用人工授精方法获取中国鲎的受精卵 ,室温下完成胚胎发育。实验结果表明 ,①中国鲎成熟卵为黄色或浅黄色 ,卵径 2 7～ 3 5mm ,扫描电镜下厚而韧的卵壳上有许多大小不同的微孔 ,精子头部椭圆形 ,具一盘状顶体囊 ,尾呈鞭毛状 ;②中国鲎的胚胎发育可分为卵裂期、囊胚期、原肠胚形成期、附肢原基形成期、组织分化期和快速生长期 ,从受精到孵出三叶幼体约需 55d ;③中国鲎胚胎发育具有发育期长、个体差异大、部分胚胎发生滞育等特点。

Mature horseshoe crab, Tachypleus tridentatus were sampled from aquatic market in Xiamen during the period from July 1998 to July 1999. The fertilized eggs were obtained by artificial insemination, then cultured in prepared seawater at room temperature(24～30℃). The fertilized egg appeared yellow or light yellow and its size ranged from 2.7 to 3.5*!mm. Sperm of the horseshoe crab consisted of an elliptical head and a long flagellum. Under the scanning electron microscope, there were many irregular pores on the thick chorion surface and an acrosomal vesicle like a plate on the top of the sperm. The embryonic development of T.tridentatus could be divided into 6 stages: cleavage,blastoderm,gastrule,appearance of rudimental appendages,organ specialization and rapid growing stage. It took about 55 days for the embryonic development from fertilized eggs to trilobite larva. The embryonic development of the horseshoe crab showed the characteristics of long hatching period,great variations in development interval between the individuals and diapause in some embryos.