日本蟳精子结构及环境因子对精子存活率的影响

Spermatozoa morphology and influence of environmental factors on viability rates in crab Charybdis japonica

以光镜和电镜观察了日本蟳精子的形态结构,对雄体贮精囊和雌体纳精囊中的精子结构进行了比较,并研究了pH,盐度对日本蟳精子存活率的影响规律,结果表明:日本蟳精子为非鞭毛型,主要由顶体、核杯、膜复合体和辐射臂等组成,其中顶体呈球形或近球形,可分成头帽、顶体管和顶体囊三部分。核杯包裹整个顶体外围,染色质呈细丝状或颗粒状。辐射臂向精子四周发出,内含核质,没有运动能力。雄体贮精囊中的精子包裹在椭球形精荚中,而雌体纳精囊中的精子呈弥散状,精子顶体管中有囊泡状结构、中心体位置前移、胞质透明区扩大,而且有些精子已崩解。精巢表面pH为6.5±0.2,精液pH为7.0±0.2,精子密度平均为(3.47×109±0.42×109)个/cm3。精子的适宜pH为7～9,最适pH为8;适宜盐度为20～30,最适盐度为25。

The morphology and structure of sperm from the crab Charybdis japonica were observed in detail with a light and electron microscope,and the ultrastructural comparison of the spermatozoa collected from male seminal receptacle and female spermatheca has been summarized.Meanwhile the physiological density and pH of sperm were measured.The influence of pH and salinity on the sperm viability rates were also studied.The mature sperm of Charybdis japonica has not any flagella,and is consists of an acrosome,nuclear cup,membrane complex and 10～20 radial arms.The spherical acrosome is comprised of apical cap,acrosomal vesicle and acrosomal tubule.The acrosome is surrounded with nuclear cup which contains filamentous or grainular chromatin.The radial arms which extend from sperm surface were filled with karyoplasem and have no capable of movement.The sperm in male seminal receptacle forms many spheroidal spermatophore,but the sperm in female spermatheca is dispersed.Several ultrastructural differences exist in two sources sperm： the sperm from female spermatheca has vesicle-like structure in acrosomal tubule,the centrosome moves forward and cytoplasmic pellucid area becomes larger than the sperm from male seminal receptacle.The pH value of testis surface in Charybdis japonica is 6.5±0.2,while the pH value of semen is 7.0±0.2.The density of sperm is 3.47×109 ±0.42×109 /mL-1.For sperm viability,the optimum pH is 7～9,and the best is 8,the optimum salinity is 20～30,and the best is 25.