2007 Volume 72 Issue 3 Pages 295-302
Adventitious root tips developing from base of cuttings and leaf samples of Herreria salsaparilha were used to determine the karyotype and to estimate DNA amount, respectively. Flow cytometry methodology was used with DAPI (4′,6-diamidino-2-phenylindole) and PI (propidium iodide) as specific DNA fluorochromes, and leaf samples of Pisum sativum (9.09 pg) as an internal standard. Cytogenetic techniques determined that H. salsaparilha has 29 pairs of homologous chromosomes (2n=58), 12 acrocentric pairs (length varying from 1.75 to 10.51 μm), 16 submetacentric pairs (1.30 to 3.45 μm), and 1 metacentric pair (2.8 μm). The DAPI- and PI-based flow cytometry analysis revealed that H. salsaparilha has nuclear DNA content 2C=5.5 pg, equivalent to approximately 5.31×109 base pairs. This karyotype asymmetric type may suggest an evolutionary process with involvement of polyploidization, being justified by the relative increased chromosome number (2n=58) and fusions.
