刘氏蝎蛉的精子发生和精子超微结构

摘要

[目的]精子超微结构在不同昆虫类群中变异较大,在昆虫种类鉴别和系统发育分析中具有重要意义.但截止目前,长翅目(Mecoptera)昆虫的精子发生和精子超微结构研究还很不充分.[方法]采用光学显微镜和透射电子显微镜技术,观察了刘氏蝎蛉Panorpa liui Hua的精子发生和精子超微结构.[结果]刘氏蝎蛉精原细胞在精囊内共分裂7次,产生128个精子细胞.这些精子细胞同步发育,成熟后结合形成数目略低于128的精子束.精子形成期,精子细胞内高尔基复合体产生的原顶体颗粒物质形成精子顶体;球状细胞核伸长、核内染色质凝集,形成致密的线形细胞核;分散的线粒体聚集、融合产生的副核转化形成2条线粒体衍生物.成熟精子由头部、颈区和长鞭毛组成.精子头部包括双层顶体和具有2条侧沟的细胞核两部分;颈区主要由中心粒和致密的鞘状中心粒侧体组成.鞭毛螺旋状,主要由l条9+2型轴丝、2条大小不等的线粒体衍生物和2条副体组成.[结论]刘氏蝎蛉精子束内精子数目略低于128,可能与精子复杂的形成过程及细胞的吞噬作用有关.线粒体衍生物在不同类群间差异显著,可为长翅目系统发育分析提供有用的特征.%[Aim] Sperm ultrastructure exhibits great variations among insect groups and has important value for species recognition and phylogenetic analysis of insects.However,spermatogenesis and sperm ultrastructure in Mecoptera have not been sufficiently studied.[Methods] The spermatogenesis and sperm ultrastructure of the scorpionfly Panorpa liui Hua were investigated by light and transmission electron microscopy.[Results] Each spermatogonium undergoes seven successive divisions in a cyst of P.liui,resulting in 128 spermatids that synchronously transform later into spermatozoa.These mature spermatozoa form a sperm bundle,but the number of spermatozoa is normally less than 128 in a bundle.During spermiogenesis,the sperm acrosome is generated by the pro-acrosomal granule material,which originates from Golgi apparatus in the cytoplasm of spermatids.The elongated nucleus is transformed through nucleus elongation and streamlining with a simultaneous condensation of chromatin.The mitochondrial derivatives are transformed from the conspicuous nebenkern,which is formed from mitochondrial aggregation and fusion in the cytoplasm of spermatids.The mature spermatozoon consists of a short head,a neck region,and a long flagellum.The head is composed of the apical bilayered acrosome and the elongated nucleus with two lateral grooves.The neck region mainly consists of the centriole and the electron-dense,sheath-shaped centriolar adjunct.The flagellum is helical and mainly comprises a 9 + 2 axoneme,two mitochondrial derivatives of different sizes,and two accessory bodies.[Conclusion] The phenomenon that the number of sperm in a sperm bundle of P.liui is usually slightly less than 128 is likely associated with the complex process of spermiogenesis and phagocytosis of cells.The mitochondrial derivatives differ distinctly among different groups and likely provide valuable characters for phylogenetic analysis of Mecoptera.