Comparative Studies On Spermatogenesis Of Four Species Of Decapoda

In this paper, the comparison of spermatogenesis and spermatozoal ultrastructures of four species of decapoda were investigated by electron microscopy (TEM). We had tried to find structural variaton between the four species during their spermatogenesis. From this comparison study, we can pursue the evolution route of the four decapods. 1. spermatogenesisMacrobrachium rosenbergii During spermatogenesis, Chromatins keep on condensing until mid-spermatid stage. The nucleus changes into two forms: fibrous and homogeneous forms . Nucleoli exist from spermatocyte stage to early spermatid stage. In this process, the numbers of ribosomes, mitochondrions and endoplasmic reticulums increase until secondary spermatocyte stage, golgi apparatus emerges at the secondary spermatocyte stage, and then, these organelles change into lamellar complex which finally forms the acrosome.Exopalarmon carinicanda There are two kinds of spermatogenium in this species, the second kind spermatogenium come from the first one. Chromatins condense in each stage at different level. The nucleus changes into two forms: fibrous nuclear and vesicular nuclear. Nucleoli do not emerge in this process. The number of the organelles increase until secondary spermatocyte stage. Mitochondria accumulate together, merging together with lysosomes and golgi bodies at the early spermatid stage, and finally the lamellar structure is formed, which forms the acrosome at last.Portunus, trituberculatus The spermatogonium exist in two different forms, the second form comes from the first one. During spermatogenesis, chromatins condense at different level. The nucleus changes into homogeneous since middle spermatid stage, and the nucleus extends into the radial arm. The number ofmitochondrion is more less than the endoplasmic reticulum, and the smooth endoplasmic reticulum is the main kind of the endoplasmic reticulum; golgi bodies and lysosomes emerge in the secondary spermatocyte stage. Finally, these organelles change into pre-acrosome vesicles which become acrosome at last.Sinopotamon chekiangense During the spermatogenensis, chronmatins condense at different level until middle spermatid stage. The nucleus has two forms at the middle spermatid stage: fibrous one and condensed one. The nucleus extends into the radial arm. The number of organelles keeps increasing until secondary spermatocyte stage. Mitochondria and ribosomes are hard to see, and the ribosome are found to adhere on the surface of endoplasmic reticulum; golgi body and lysosome do not exist, membranous ring emerges at the secondary spermatocyte stage. The organelles change into pre-acrosome vesicles at middle spermatid stage, and finally pre-acrosome forms acrosome. 2. spermal ultrastructureThe sperm ultrastructure of the Macrobrachium rosenbergii and Exopalarmon carinicanda Holthuis analogical, the whole sperm looks like a inversed umbrella, it has a main body, a spike and a little bit cytoplasm. There are some vesicle exist in the M. rosenbergii sperm nucleus. The relatively length of the spike of the E . carinicanda Holthuis is longer than that of M. rosenbergii. There are two forms of nucleus in the E. carinicanda sperm: fibrous and vesicular onesThe sperm ultrastructures of the P. trituberculatus and S. chekiangense consist of nucleus cup ,radial arm, acrosome. The ultrastructure of the acrosome is made up of acrosome cap, acrosome vusicle, acrosome tubule and the acrosome valve .P. trituberculatus has homogeneous sperm nucleus, and S. chekiangense consists of fibrous and condensed sperm nucleus. The number of radial arms in P. trituberculatus is less than the latter's. the sperm of P. trituberculatus is round in shape, and that of S. chekiangense is square in shape. Tthe centriole locates at the base of the acrosome tubule in S. chekiangenser, but it locates at the acrosome valve . In P. trituberculatus. The location of the center tubule in the two species is different. In P. trituberculatus it locates at the top of the acrosome tubule, and in S.chekiangenser it locates...