日本沼虾精子发生的研究

对日本沼虾精子发生全过程的电镜观察表明：精原细胞核染色质分散，胞质内有线粒休、内质网的分布。初级精母细胞核染色质块状，不均匀地分布于核中，内质同多小泡多。次级精母细胞核染色质大多分布于核膜内侧，内质网聚集成团，精细胞分化形成精子的早期，胞核增大，核侧形成内质同多小泡的聚合体；中期的核内染色质浓缩，同时形成空囊状结构，

SPERMATOGENESIS OF FRESHWATER SHRIMP MACROBRACHIUM NIPPONENSE (CRUSTACEA, DECAPODA)

The spermatogenesis of freshwater shrimp ( Macrobrachium nipponense) was studied with transmission electron microscope (TEM) and scanning electron microscope (SEM). The spermatogonium has mitochondria, rough endoplasmic reticulum and dispersed chromatin. The primary spermatocyte is smaller than the spermatogonium, its chromatin becomes denser. The rough endoplasmic reticulum of the secondary spermatocyte is assembled and produces many vesicles. In the early spermatid, the nucleus becomes bigger, and a concentrate of endoplasmic reticulum forms beside the nucleus. In the middle spermatid, many small dense particulates are produced by the endoplasmic reticulum vesicles, the nuclear material is condensed, and the nucleus is composed of chromatin lump and vesicular structure. In the late spermatid, the cytoplasmic projection develops into spike, and the endoplasmic reticulum develops into cross striated fibrils. The mature sperm has a cup shaped main body, which cosists of cytoplasmic band and nuclear region. The nucleus s composed of vesicular zone and membrane zone, and the radial fibrils converge at the center of the base, then extend to form spike.