Chromosome banding in the genus Pinus IV. Fluorescent banding patterns of chromosomes in eight taxa of haploxylone pines

Abstract

Somatic chromosomes of seven taxa of Asian haploxylon pines, Pinus armandii var. amamiana, P. armandii var. armandii, P. parviflora, P. pumila, P. x hakkodensis, P. koraiensis and P. bungeana, and a American species of P. edulis were observed by a fluorescent banding method using chromomycin A₃ (CMA) and 4’,6-diamidino-2-phenylindole (DAPI). The chromosome number of all taxa was 2n=24 and their karyotypes were composed of 22 long metacentric chromosomes and two short heterobrachial chromosomes as previous reports. CMA-bands appeared at the interstitial region and not at the proximal region of metacentric chromosomes. Interstitial CMA-bands were observed on 16-18 long metacentric chromosomes in chromosome complement of most species excepting for P. bungeana having six interstitial CMA-bands. The short chromosomes of most species have an interstitial CMA-band on their long arms and that of P. edulis had a proximal CMA-band. Clear proximal CMA- or DAPI-bands appeared in most species of subgenus Pinus were not observed in species of subgenus Strobus examined. DAPI-dots appeared at centromeric regions of all chromosomes and many thin DAPI-bands did at interstitial regions as appeared in the species of subgenus Pinus. The karyotype analysis combined with CMA- and DABI-bandings was useful for identification of each homologous chromosome and for chromosomal relationship among species in haploxylon pines.