The developmental cytology of the nuptial pad in the red-spotted newt☆
[摘要] Theultrastructureofdeveloping,matureandregressingnuptialpadshasbeenexaminedandinterpretedinthered-spottednewt.Thedevelopmentofthepadbeginswithathickeningofthedermis.Mitoticactivitythenincreasesthecelllayersoftheepidermisfromaboutfourtoapproximatelyeight.Simultaneously,keratinocyticsyntheticactivityshiftstoproducemoretonofilamentsandfewermucousgranules.Intheuppercelllayers,theshiftisfollowedbyanincreaseincytoplasmicvolumewithbundlesoftonofilamentsaccumulatingontheanteriorsideofeachcell,displacingthenucleusposteriorly.Afterthisrearrangement,theenlargedcellsbecomegroupedintoascendingcolumnsthattiltposteriorlyfromthebasalepidermallayeratanangleofabout45°.Alsotheflattenedcellsofthemonolayeredstratumcorneumbecomesuperficiallyroughenedandwithsuccessivemoltsarereplacedbyorderlyrowsofcornifiedconicalstructurespossessingcuspsthataredirectedposteriorly.Eachconethenliesatthetopofoneofthegerminativecolumns.Inrudimentarypadsinducedonfemalenewts,theepidermisattainsaheightofonlyfiveorsixlayersandcolumnsarenotevident,butotherdevelopmentalfeaturesofthemalearepresent.Duringregression,mitosisisslowedandthedevelopmentalsequenceisreversed.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
