Ultrastructure of rosy barb Puntius conchonius spermatozoon
HU Jia-Hui~(1,2),ZHANG Yong-Zhong~(2),FU Chong-Luo~2,LIU Xue-Zhou~31. College of Marine Biology,Ocean University of China,Qingdao 266003,Shandong,China2. College of Life Science,Liaocheng University,Liaocheng 252059,Shandong,China3. Yellow Sea Fisheries Research Institute,Chinese Academy of Fishery Science,Qingdao 266071,Shandong,China
Transmission and scanning electron microscopy revealed that the spermatozoon of the rosy barb Puntius conchonius consists of an acrosome-less ovoid head,a midpiece and a flagellum.The head mainly consists of the nucleus.There is only a thin layer of cytoplasm between the plasmalemma and the nucleus.The nucleus contains dense chromatin.At the caudal-lateral end of the nucleus there is a shallow nuclear fossa,which partly holds the centriolar complex.The centriolar complex consists of the proximal and distal centrioles,arranged at an obtuse angle with the flagellum linked to the end of the distal centriole.The midpiece is composed of the anterior chief segment,the collar,containing several irregular mitochondria embedded in the cytoplasmic mass,and a slender caudal segment of variable length,the sleeve,behind the collar.The midpiece is separated from the anterior segment of the flagellum by a plasmic channel.Both the head and the midpiece are in asymmetrical emplacement to the position of the flagellum.The flagellum possesses a conventional 9+2 axoneme with no lateral fin.Compared to the structures of other Cyprinidae fish spermatozoa,the main characteristics of this spermatozoon are the variable length of the sleeve,the different vesicles and various pores of the collar.It seems that the number of vesicles and the sleeve length is correlated,this may have some relationship with sperm aging.