Differential Giemsa staining in plants : III. DNA base composition

DNAs isolated from three cultivars of Tulipa displaying a range of constitutive heterochromatin (<10% to 40%), showed very little or no difference in DNA base composition as determined from buoyant densities and thermal transition profiles. Four possible explanations for the interactions of the Giemsa dye and the chromatin are discussed with reference to the mechanism of Giemsa banding. A method for the rapid isolation of higher plant DNAs is described.