Chromosome banding in the genus Pinus V. Fluorescent banding patterns in 16 diploxylon pines

Abstract

In Pinus, Subgenus Pinus 16 species were investigated on their somatic chromosomes by a fluorescent banding technique using chromomycin A₃ (CMA) and 4',6-diamidino-2-phenylindole (DAPI). The chromosome number of 2n=24 was commonly counted in all the species studied. Their karyotypes were composed of many long metacentric chromosomes and a few short submetacentric chromosomes, and two karyotypes were recognized in respect to number of short chromosomes in the subgenus. CMA-bands appeared at an interstitial and/or proximal region of chromosomes and DAPI-band did at a proximal region. Thin DAPI-bands appeared at interstitial regions and DAPI-dots appeared at a centromeric region in most chromosomes. In a chromosome complement each homologous chromosome was identified on the base of its shape and fluorescent banding pattern. The typical banding patterns were compared among the species studied. Many interstitial CMA-bands at the secondary constrictions appeared on many metacentric chromosomes. Proximal fluorescent bands varied in fluorescent nature and number and divided into several groups. Section Pinus short three chromosome pairs were two or three patterns of fluorescent banding. The section Trifolae species had many proximal DAPI-bands and less proximal CMA-bands than section Pinus. The shortest chromosome had proximal bands indicating two groups on the kinds of fluorescent band.