多刺裸腹溞孤雌溞的卵子发生

采用光镜和透射电镜技术观察多刺裸腹溞（Moina macrocopa）孤雌溞卵子的发生过程。根据卵母细胞细胞核的形态、卵黄的合成、积累情况及核物质的形态变化等观察结果,将卵子发生分为3个时期：卵原细胞期、卵母细胞期和成熟卵母细胞期。卵原细胞核大,胞质层薄,有少量线粒体分布,核物质浓缩为一团;卵母细胞发育的早期和中期细胞体积增大,细胞质层增厚,线粒体迅速增多,细胞核变圆,核物质分散成多块;后期卵母细胞胞质中开始出现大量卵黄颗粒和少量脂滴,细胞核边缘波浪化,线粒体空泡化,其中卵黄合成初期,核物质重新聚集在细胞核中央,在卵黄合成中期又分散开来;成熟卵母细胞质中充满卵黄颗粒,呈强嗜酸性,细胞核的形态呈不规则状,核物质分散。多刺裸腹溞生殖腺的外部形态随着生殖周期的变化而不同。在孤雌溞的整个生活史中生殖腺内卵子的发育经历了“同步一不同步一局部同步”的发育模式。发现1龄幼溞生殖腺中不存在卵原细胞,成龄溞的生殖腺有多个发育时期的生殖细胞并存。同时在亚显微水平上发现卵黄主要由线粒体演变而来,也通过吞饮作用吸收成熟的卵黄颗粒,内源与外源性共同作用形成卵黄。中国水产科学,2006,13（4）：547—554]

Oogenesis in parthenogonidium of Moina macrocopa Straus (Crustacea ,Diplostraca)

The features of oogenesis in parthenogenetic Moina macrocopa were observed under light and electron microscope.According to the shape of nucleus and the vitelline accumulation,oogenesis might be divided into three stages: oogonia,oocyte and mature oocyte.Transmission electron microscopy(TEM) exhibited the ultrastructure of parthenogenetic eggs.The oogonia have big nuclear,thin cytoplasm and several mitochondria.Other organelles,such as golgi bodies and lysosomes were not observed in oogonia.The cytoplasm of oocyte in nonage and metaphase was incrassate,the nucleus became round,and the number of mitochondria increased quickly.In early developing stages,the nuclear membrances were relatively smooth.But they became wavy in terminal oocyte,like amoebas.At the same time,yolk granules appeared abundantly,and the number of cristae in mitochondria decreased.Finally,mitochondria only left a vacuole.Mature oocytes were full of yolk granules and lipids,strongly addicting to acidity.The shape of nuclear was abnormal.There were a great number of mitochondria vacuoles in cytoplasm.The external modality of gonad seasonally changed with periodical reproduction.Oogonium did not exist in the first juvenile instars.Instead,the ovary in first juvenile stage was full of nonage oocyte.In the second juvenile instars, there were several kinds of oocyte in different stages.But metaphase oocytes were in the highest amount.Yolk granules began to appear in some oocytes.When the ovary was mature,the oocyte was full of yolk granules.In all,the development of ovum experiences a mode like "synchrounsynchro-partically synchro".Oocyte of several different stages may exist simultaneously in the mature gonads.Yolk granules may evolve from mitochondria.Oocyte also can absorb mature yolk granules.The synthesization of yolk has two different ways.