SPERMATOGENESIS, SPERM STORAGE AND COMPARATIVE SPERM MORPHOLOGY IN 9 SPECIES OF CAPITELLA, CAPITOMASTUS AND CAPITELLIDES (POLYCHAETA, CAPITELLIDAE)
SPERMATOGENESIS, SPERM STORAGE AND COMPARATIVE SPERM MORPHOLOGY IN 9 SPECIES OF CAPITELLA, CAPITOMASTUS AND CAPITELLIDES (POLYCHAETA, CAPITELLIDAE)
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DOI：
10.1007/bf00409572
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发表时间：
1987-01-01
期刊：
影响因子：
2.4
通讯作者：
GRASSLE, JP
中科院分区：
文献类型：
--
作者：
ECKELBARGER, KJ;GRASSLE, JP
利用光学显微镜和透射电子显微镜（TEM）对Capitella的5个亲缘种、Capitomastus属的3个种和Capitellides属的1个种的精子发生、成熟精子和精子贮存器官的形态进行了观察。这些头虱缺乏发育良好的睾丸，但年轻的雄性在第八节有一些专门的腹膜区域，生殖细胞增殖，精原细胞被释放到体腔中，精子发生完成。成熟的精子储存在成对的生殖导管（coelomoducts）的中心区域，位于第七和第八个setigs之间。形成体腔壁和导管中心区域的细胞是纤毛的，并且有大量的糖原沉积。管腔边缘有广泛的微绒毛，有证据表明它们将含糖原的物质分泌到导管中。所有种类的原始精子都具有圆锥形的顶体、细长的核和沿着鞭毛近端部分延伸的长的中间部分。一个单一的环形的细胞核环绕着中间的中心粒区域，细胞质中充满了糖原。9个种的精子在中段长度、顶体长度、尤其是核长度上存在显著差异。核长度在Capitella和Capitomastus的兄弟物种之间有两倍的范围。Capitella兄弟种的顶体囊泡和顶体空间characterstic的形状和体积的细微差异似乎与这些物种的二倍体染色体数目为20或26的基本划分相关。精子发生、产生的精子数量和精子储存方法是精子在受精中有效利用的适当条件。没有证据表明精子包在个体之间形成和转移，精子转移的方法也不清楚。成熟精子的尺寸和顶体形态的差异，以及先前在Capitella兄弟物种的卵包膜中表现出的专业化，是这些Capitellid物种之间存在的生殖隔离的特征。
Light microscopy and transmission electron microscopy (TEM) were used to describe spermatogenesis and the morphology of mature sperm and sperm storage organs in five sibling species of Capitella, three species in the related genus Capitomastus, and one species in the genus Capitellides. These capitellids lack a well-developed testis, but young males have a few specialized regions of the peritoneum in the eighth setiger, where germ cells proliferate and spermatogonia are released into the coelom, and spermiogenesis is completed. Mature sperm are stored in the central regions of paired genital ducts (coelomoducts), which lie between the seventh and eighth setigers. The cells forming the walls of the coelomostome and central region of the duct are ciliated and have large glycogen deposits. The lumenal borders have extensive microvilli and there is evidence that they secrete glycogen-containing materials into the duct. All species have modified primitive sperm with a conical acrosome, elongated nucleus, and long middle piece extending along the proximal portion of the flagellum. A single ring-shaped mitochondrion encircles the centriolar region of the middle piece and the cytoplasm is filled with glycogen. The sperm of all nine species differ significantly in the lengths of their middle pieces, acrosomes and especially in their nuclear lengths. The nuclear lengths have a twofold range among the sibling species of Capitella and Capitomastus. Subtle differences in the shape and volume of the acrosomal vesicle and acrosomal space characterstic of the Capitella sibling species seem to correlate with a basic division of these species into those with diploid chromosome numbers of 20 or 26. Spermiogenesis, the number of sperm produced, and the method of sperm storage are appropriate for efficient sperm utilization in fertilization. No evidence indicates that spermatophores are formed and transferred between individuals and the method of sperm transfer is not understood. The differences in the dimensions and acrosome morphology of mature sperm, and the previously demonstrated specializations in the egg envelopes in the Capitella sibling species, are characteristic features of the reproductive isolation that exists among these capitellid species.