前臀鮡和贡山鮡精子的超微结构与运动学参数比较OA

To investigate the sperm ultrastructure and kinematic characteristics of Pareuchiloglanis an-teanalis and Pareuchiloglanis gongshanensis,a systematic comparative analysis was conducted using scan-ning electron microscopy(SEM),transmission electron microscopy(TEM),and a computer-assisted sperm analysis(CASA)system.The results revealed that,although the spermatozoa of both species con-sist of an acrosome-less head,a midpiece,and a single flagellum,they exhibit significant divergences in morphological configuration and swimming patterns.The spermatozoa of P.anteanalis were relatively lon-ger,characterized by a slender head(length-to-width ratio:1.51),a midpiece containing four umbrella-shaped,tightly arranged mitochondria,and a flagellum with symmetrical lateral fins.In contrast,the sper-matozoa of P.gongshanensis were shorter,featuring a nearly spherical head(ratio:1.08),a midpiece with 4-5 smaller mitochondria,and a shorter flagellum with more developed lateral fins.CASA measurements revealed no significant differences in average path velocity(VAP),straight-line velocity(VSL),or curvi-linear velocity(VCL)between the two species.However,P.anteanalis sperm exhibited significantly high-er straightness(STR)and beat-cross frequency(BCF)(P<0.05),resulting in a more linear swimming trajectory.Conversely,P.gongshanensis sperm showed a significantly greater amplitude of lateral head dis-placement(ALH)(P<0.05)and a more curved movement path.This study indicates that P.anteanalis sperm exhibit the classic"introsperm"phenotype adapted for internal fertilization,whereas P.gongshanen-sis sperm display traits characteristic of"aquasperm",reflecting an adaptation to external fertilization.