ORCEIN AND FLUORESCENT BANDING ANALYSIS OF TWO FLORAL TYPES OF CATHARANTHUS ROSEUS L.

Abstract

Two floral types of Catharanthus roseus L. viz. pink and white were studied
through differential staining with orcein, CMA and DAPI for cytogenetical
characterization and to assist towards updating their taxonomical status and
evaluating chromosomal diversity between them. "Simple Chromocenter Type"
of interphase nuclei was observed with some darkly stained small heterochromatic
regions throughout the nuclei. Most of the prophase chromosomes of
Catharanthus roseus (pink and white) were "Continuous Type" and a few were
"Gradient Type". Although these two floral types possessed 16 metacentric
chromosomes in somatic cells, they showed variation in fluorescent banding
pattern considering the modification of GC- and AT-rich repetitive segments.
Taking into account all the parameters of both the floral types of C. roseus
showed strict symmetric karyotype as well as primitive nature. Therefore, the
combined data of differential staining provide information to make comments on
their chromosomal status with cytogenetical characterization and also create a
baseline for future research.