Early development of zooxanthella-containing eggs of the corals Pocillopora verrucosa and P-eydouxi with special reference to the distribution of zooxanthellae
Early development of zooxanthella-containing eggs of the corals Pocillopora verrucosa and P-eydouxi with special reference to the distribution of zooxanthellae
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DOI：
10.2307/1542708
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发表时间：
2000-08-01
影响因子：
1.6
通讯作者：
Hidaka, M
中科院分区：
文献类型：
--
作者：
Hirose, M;Kinzie, RA;Hidaka, M
有些造礁石珊瑚产卵时含有虫黄藻。我们遵循的两个这样的物种，Pocillopora疣状和P. evdouxi的含虫黄藻卵的发展。我们还记录了虫黄藻在发育过程中的分布模式的变化。两种鱼卵母细胞在产卵前3 ~ 3d摄取虫黄嘌呤。起初，虫黄藻在卵母细胞中均匀分布，但后来它们转移到含有萌发囊泡的半球。受精后，早期卵裂事件是全胚性的，由沟形成进行。第一条卵裂沟始于含有虫黄藻的半球，将受精卵的虫黄藻补充物大致均等地分成两个分裂球。第二次分裂将每个卵裂球分成一个富含虫黄藻的细胞和一个几乎没有虫黄藻的细胞。随着细胞分裂的继续，含有虫黄嘌呤的卵裂球进入囊胚腔。第一次卵裂后约5 h，囊胚腔消失，胚胎中央区域充满含虫黄质或脂滴的细胞，形成一个静原肠胚。我们的研究结果表明，只有卵裂球已被确定为发展成胃胚层细胞接受虫黄嘌呤在卵裂。这种决定似乎发生，最迟，在四细胞阶段的第二次细胞分裂。
Some hermatypic corals spawn eggs that contain zooxanthellae. We followed development of zooxanthella-containing eggs of two such species, Pocillopora verrucosa and P. evdouxi. We also documented changes in the distribution pattern of zooxanthellae during development. Oocytes of both species took up zooxanthellae 3 to 3 days before spawning. At first, zooxanthellae were evenly distributed in oocytes, but they later moved to the hemisphere that contained the germinal vesicle. After fertilization, early cleavage events were holoblastic, progressing by furrow formation. The first cleavage furrow started at the hemisphere that contained zooxanthellae, dividing the zooxanthellate complement of the zygote about equally into the two blastomeres. The second division divided each blastomere into one zooxanthellae-rich cell and one with few zooxanthellae. With continued cell division, blastomeres containing zooxanthellae moved into the blastacoel. The blastocoel disappeared at about 5 h after the first cleavage, and the central region of the embryo was filled with cells containing either zooxanthellae or lipid droplets, forming a stereogastrula. Our results suggest that only blastomeres that had been determined to develop into gastrodermal cells receive zooxanthellae during cleavage. This determination appears to take place, at the latest, by the second cell division at the four-cell stage.