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 heteroch romatin. 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 seque ntial staining, sequential N-banding and silver impregnation. Four cla sses of constitutive heterochromatin were recognized: CSRs, nucleolar organizers, non-nucleolar chromomycin-positive bands, and indifferentl y fluorescent bands. The banded karyotype of C. aurantiacum is compare d with those of other Cestrum species. The sections Habrothamnus and C estrum are not karyologically distinct.