黄海高眼鲽卵巢发育特征及卵径分布

A Study on the Ovary-Development Characters and Oocyte Size-Distribution of Cleisthenes herzensteini in the Yellow Sea

中文关键词: 高眼鲽  卵巢发育  组织学  卵径分布

英文关键词: Cleisthenes herzensteini  Ovary development  Histological characters  Oocyte size- distribution

中文摘要:

      本研究通过组织学观察，描述了黄海高眼鲽(Cleisthenes herzensteini)卵母细胞发育特征及其退化过程。高眼鲽卵母细胞发育分为5个时相：第1时相为卵原细胞，细胞体积小，细胞质少，细胞核明显；第2时相卵母细胞细胞核附近出现卵黄核；第3时相由胞质外缘向内层逐渐产生液泡并生成卵黄颗粒，出现双层滤泡膜；第4时相卵母细胞内充满卵黄，细胞核向动物极移动，放射膜增厚；第5时相细胞核溶解，卵母细胞从滤泡膜中释放出来并发生水合作用；产卵期过后，卵巢发生退化，卵黄颗粒逐渐被吞噬，放射膜溶解断裂。通过比较卵巢中各时相卵母细胞组成比例，表明卵母细胞发育具有非同步性。Ⅳ、Ⅴ、Ⅵ-Ⅳ¢期卵巢内卵径(长径)呈单峰分布，优势粒径组分别为0.45~0.55 mm、0.60~0.65 mm和0.40~0.50 mm；Ⅴ¢期卵巢，卵径分布呈双峰型，峰值分别为0.50~ 0.55 mm和0.90~0.95 mm，水合卵母细胞与卵径较小的小生长期卵母细胞比例增大，呈现出明显的双峰分批产卵型特征。

英文摘要:

      This study investigated the development and resorption of the oocyte of Cleisthenes herzensteini in the Yellow Sea, using light microscopy and morphometric methods. Oocyte development was divided into five phases, based on morphological criteria and nutrition accumulation. Oocytes in phase I were small, with little cytoplasm. In phase Ⅱ, oocytes were distinguished by the appearance of yolk nucleus near the cell nucleus. In phase Ⅲ, cortical vacuoles first appeared on the edge of the cytoplasm and then extended to the center, with the occurrences of crystalline yolk and double follicular membrane. Oocytes in phase Ⅳ were full of non-crystalline yolk, with the cell nucleus moving towards the animal pole and the zona radiate becoming thicker. In phase Ⅴ, the cell nucleus of the oocyte dissolved, and the hydrated oocyte was released from the follicular membrane. Ripe ovary that had not ovulated completely was in turn resolved, with the yolk absorbed and the zona radiate ruptured after the spawning season. In addition, this study showed that C. herzensteini was characterized by asynchronous oocyte development and batch spawning, based on histologic observations of the different stages of the ovary and the oocyte size-distribution method. The sizes (major axes) of the oocytes in the stage Ⅳ, Ⅴ, and Ⅵ-Ⅳ¢ ovaries had unimodal distributions, with the three modes at 0.45~0.55 mm, 0.60~0.65 mm, and 0.40~0.50 mm, respectively. Oocyte size distribution was bimodal for stage Ⅴ¢ ovary, the oocytes mainly distributed at both 0.50~0.55 mm and 0.90~0.95 mm, with the percentage of hydrated oocytes and small oocytes increased. The two dominant size groups of oocytes in the stage Ⅴ¢ ovary were well separated with a clear hiatus, and the oocytes in the larger-size group were all hydrated, which was in accordance with the characteristics of batch spawners. In the course of protecting C. herzensteini resources, we should take into account their reproductive characteristics.