COLD-SENSITIVE CHROMOSOME REGIONS AND HETEROCHROMATIN IN CESTRUM-AURANTIACUM (SOLANACEAE)

The karyotype of Cestrum aurantiacum was analyzed for the presence of cold-sensitive regions (CSRs) and other types of constitutive heterochromatin. A range of techniques was employed including the fluorescent DAPI, chromomycin/DAPI double staining and actinomycin D/DAPI counter-staining, and the non-fluorescent C-banding applied as single or sequential staining, sequential N-banding and silver impregnation. Four classes of constitutive heterochromatin were recognized: CSRs, nucleolar organizers, non-nucleolar chromomycin-positive bands, and indifferently fluorescent bands. The banded karyotype of C. aurantiacum is compared with those of other Cestrum species. The sections Habrothamnus and Cestrum are not karyologically distinct.