CYTOPHOTOMETRIC AND BIOCHEMICAL ANALYSES OF DNA VARIATIONS IN THE GENUS ALOE-L

The nuclear 4C DNA content in 10 species of Aloe L. (Liliaceae), determined by Feulgen cytophotometry, was found to vary by 35.8%. Absorption measurements of the nucleus showed that this variation is positively correlated with changes in the amount of heterochromatin, although quantitative variations in euchromatin cannot be excluded. Buoyant density analyses of extracted DNA in CsCl gradients showed differences in DNA density among species and the possible presence of satellite DNA in some species. These variations might have played a role in Aloe speciation. In general, the experimental data are in agreement with the accepted taxonomic position of the examined species.