감성가자미, Pleuronectes obscurus (Herzenstein)의 난발생과 체세포 분열주기

Abstract

Black plaice, Pleuronectes obscurus (Herzenstein), were collected from the coastal areas of Hari, Young-do, Busan, Korea, from February to March 2007 and fertilized in order to observe egg development and temperature-related cleavage rates and mitotic intervals (τ0).

The fertilized egg is demersal and adhesive, and measuring 0.84±0.010 ㎜ in diameter. The eggs contain no oil globules. After 1 hr 45 min, the blastodisc formed. The 2-, 4-, 8-, 16-, 32- and 64-cell stages were attained in respective times of 2.5, 3.5, 4.5, 5.5, 7.5,and 8.5 hr

the morula stage in 10 hr and the blastula stage in 16 hr. The eggs began the gastrula stage in 20 hr and formated of the embryonic body in 27 hr. The optic vesicles appeared in 44 hr, the auditory vesicles and Kupffer's vesicle in 72 hr. Kupffer's vesicle had disappeared and movements of heart and tail were observed in 90 hr. Hatching took place 121 hr after fertilization at 14℃. The hatched larvae were 3.5±0.16 ㎜ in total length.

The first cleavage stage occurred at 190~195, 160~165, 125~130, 75~80, 60~65 and 45~50 min at 6, 10, 14, 18, 22 and 26℃, respectively. At higher temperatures, eggs developed faster and underwent further identical development. For black plaice, τ0 were 83.44±3.076, 71.53±3.060, 63.12±2.109, 45.09±2.780, 39.96±2.095 and 30.44±3.354 min at 6, 10, 14, 18, 22 and 26℃, respectively. There were strong negative correlations between the τ0 and water temperatures at all temperatures (Y=-2.6981X+98.767, R2=0.9831, where Y is τ0 and X is temperature).