简介：Soakedindifferentconcentrationsofholmiumnitratesolutionfordifferenttime,roottipsofViciafabawerewashedandfetched.DNAoftheroottipswasextractedandperformedagarosegelelectrophoresis.Slidesoftheroot-tipcellswerepreparedandexaminedundermicroscopeforanomalousnuclei.Meanwhile,root-tipcellswerepreparedandperformedsinglecellgelelectrophoresis.Theresultsshowthatanomalyofnucleiisinducesbyholmiumions.Theresltsalsoshowthatcomettailsarelengthenedandnumbersoftailedcellsareontheincreaseswiththeextensionofdisposalwithin24hatconcentraitionof8mg·L^-1.andthatatdisposalof24h,anobviousandcontinualtapeappearesmagarosegelelectrophoresls,butatdisposalof48h,thecomettailsareshortenedandonlyashorttailingtapeshowsinagarosegelelectrophoresis.ItmaybetheresultofDNArepairorDNAcross-link.Atconcentrationof64mg·L^-1fordisposalof24h,thecomettailsareshorterthanthoseat8mg·L^-1forthesametime.Furthermore,fracturesofnucleiwereobservedundermicroscope,butnotailingtapewasfoundinagarosegelelectrophoresis.NeithertypicalDNAladder,norcharacteristiccomettails'shapeofapoptosiswasfoundintheexperiments.