蓝铃花根尖染色体核型分析及其核糖体DNA与端粒重复序列的荧光原位杂交定位OA

To elucidate the genetic relationship and evolutionary variations among different flower colors of bluebell(Hyacinthoides non-scripta),a cytological analysis was conducted to provide reliable evidence for polyploid breeding strategies.Karyotype analysis and fluorescence in situ hybridization(FISH)using 45S rDNA,5S rDNA,and te-lomere repeats as probes were performed on white-flowered and blue-flowered bluebells.Karyotype analysis revealed that the white bluebell was diploid,with a chromosome number of 2n=2x=16,with an average arm ratio of 4.07,a karyotype asymmetry coefficient of 75.18％,and a karyotype formula of 2n=2x=16=2m+6sm+4st+4t(sat).The blue bluebell was triploid,with a chromosome number 2n=3x=24,with an average arm ratio of 4.27,a karyo-type asymmetry coefficient of 75.20％,and a karyotype formula of 2n=3x=24=3m+9sm+6st+6t(sat).Both varieties exhibited a 3B karyotype,with satellite DNA located at the ends of the short arms of two pairs of telocentric(t)chromosomes.The 45S rDNA signals were localized on the chromosomal secondary constrictions and 5S rDNA signals were localized on the top of the long arm of the metacentric(m)chromosome by FISH results.Telomeric re-peat sequences were uniformly distributed at both ends of each chromosome,without interstitial signals.White blue-bells displayed four 45S rDNA and two 5S rDNA signal sites,while blue bluebells exhibited six 45S rDNA and three 5S rDNA signal sites.Karyotype analysis and FISH signal localization indicated that blue bluebells likely originated from whole-genome duplication of the white bluebell,providing a cytological theoretical basis for polyploid breeding in bluebells.