When do sperm of the sea urchin, Pseudocentrotus depressus, undergo the acrosome reaction at fertilization?

[摘要] Jellycoatsoftheseaurchin,Pseudocentrotusdepressus,werestrippedofftheeggs,andtheeggswere“inseminated.”Afterpenetrationthroughtheisolatedjellyhull,spermswarmedinthecavitypreviouslyoccupiedbytheegg.Electronmicroscopicexaminationcouldnotdetectanyspermwithreactedacrosome.Observationwasalsomadeofthespermpenetratingthroughtheintactjellycoat-eggcomplex.Althoughanumberofspermwereexaminedinultrathinsections,onlythoseattachedtothevitellinelayerhadundergonetheacrosomereaction;thosespermembeddedinjellybutnotattachedtothevitellinelayerhadnotundergonetheacrosomereaction.Thesequenceofeventsinfertilizationofthisspeciesandofotherechinoidsisdiscussed.

[学科分类] 生物科学（综合）