日本沼虾Macrobrachium nipponense（de Haan）卵子附着机制研究I．卵膜及卵子附着的扫描电镜观察

用扫描电镜技术观察了日本沼虾（Ｍａｃｒｏｂｒａｃｈｉｕｍｎｉｐｐｏｎｅｎｓｅ）成熟卵、人工授精卵及自然受精产出附着于腹肢上的卵。成熟卵只有初级卵膜，表面较光滑，上密布微孔，密度约１～２个／μｍ２；人工授精卵表面首先突起大小不同的颗粒，随后颗粒破裂并消失，同自然受精卵一样，卵表略光滑，呈波浪状起伏，微孔密度与未受精前大致相同；自然产出的受精卵，表面覆盖一层由雌体腹肢分泌的次级卵膜。次级卵膜具有保护、选择性渗透及隔离邻近受精卵的作用。腹肢不断摆动，受精卵在腹肢间滚动并形成卵与卵之间以及卵与刚毛之间两种“卵柄”，一种称为卵索（ｆｕｎｉｃｕｌｕｓ），不与刚毛相连。ｆｕｎｉｃｕｌｕｓ扁带状，与卵接触处较宽，约１４０～１５０μｍ，中间宽约３０～４０μｍ；另一种称为卵柄（ｅｇｇｓｔａｌｋ），由１～２根载卵刚毛（ｏｏｓｅ－ｔａｅ）插入次级卵膜形成，与卵接触处次级卵膜突起呈锥状，基部宽约１４０～１５０μｍ。非载卵刚毛起辅助抱卵作用。

Studies on the Mechanism of Egg Attachment inMacrobrachium nipponense(de Haan) I. Scanning Electron Microscopy Observation of Egg Membranes and Egg Attachment

The mature egg, artificial inseminated egg and natural spawned eggs, which are attached to the pleopods, were observed by scanning electron microscopy technique. The results show that, the mature egg of Macrobrachium nipponensehas smooth primary oolemma, with micropores on it, 1～2 individuals/μm 2in density. After inseminated, the egg surface appears granular-like process, which later disappear, and become a little smooth, with wave-like structure. Naturally spawned eggs are covered by the second oolemma, which were formed by the secretion of cement glands in pleopods. The second oolemma can function in protection, seletive permeability and separating the neighboring eggs by foming funiculus. With continued rocking movements of the female pleopods, the fertilized eggs rolling in the brooding chamber, the soft elastic outer shell of the eggs were draw out into funiculus and/or egg stalk. Funiculus is ribbon-like, with 140～150μm in wideth at the base, and 30～40μm in the middle. Egg stalk is formed by 1～2 oosetae penetrating into the second oolemma, with cone-like process at the base, and 140～150μm in wideth. Non-oosetae act as assistance in egg carring.