Interkalare Regeneration und segmentale Gradienten bei den Extremit?ten von Leucophaea-Larven (Blattaria): II. Coxa und Tarsus

摘要

RecentexperimentsontheregenerativecapacityofthelarvalextremitiesofLeucophaeahaveledtotheconceptionofsegmentalgradientswithmorphogeneticpotencies.Ifonecombineswoundareasfromdifferentregionsofasegmentbearingdifferentlevelsofthegradient,anintercalaryregeneratewilldevelopandreplacethemissingpartsofthegradient.Nowexperimentshavebeendoneinordertoelucidatethegradientsinsegmentsotherthanfemurandtibia,thesegmentsforwhichtheconcepthadbeendeveloped.Toprovethegradientconcept,onemayperformthreedifferenttypesofexperiments;providedthegradienttheoryisright,thefollowingresultsshouldbeobtained:1.(1)Combiningwoundareasofthesamelevel:healingwithoutregeneration.2.(2)Producingastepinthegradientdescendingfromproximaltodistal:intercalaryregeneratewithnormalpolarity.3.(3)Producingastepdescendingfromdistaltoproximal:regeneratewithreversedproximodistalpolarity.Experimentshavebeenperformedbycombiningsegmentsofthetarsuswithoneanother,bycombiningthefirstorfifthsegmentofthetarsuswiththetibia,andbycombiningfemurwithcoxa.Theresultsshowthattheconceptofsegmentalgradientsmaybeextendedtoallsegmentsoftheextremitywiththepossibleexceptionofthetrochanter.Thetrochanter,inthisrespect,seemsnottobeadistinctsegmentbutmaybeassociatedwiththebaseofthefemur.Thelevelsofthegradientsinthedifferentintersegmentaljointsarecomparable.Onepartoftheregeneratessuggeststhat,beyondthesegmentalgradients,theremaybeanothersystemofproximodistaldiversitiesdifferingfromonesegmenttoanotherandparticipatinginthedevelopmentoftheintercalaryregenerates.