Comparative Karyotype Analysis of Typhonium trilobatum L. and its two Morphological Forms

Abstract

Typhonium trilobatum (Typical form) and its 2 morphological forms viz. Tall and Slender were cytogenetically investigated. The Typical and the Tall form were found to possess 2n=18 chromosomes whereas the Slender one has 2n=19 chromosomes. The extra chromosome of the Slender form was a regular member of pair IX. The centromeric formula of the Tall form was 12m+6sm. It was 16m+2sm and 17m+2sm in the Typical and the Slender form, respectively. The orcein-stained interphase nuclei and prophase chromosomes revealed that the Tall form had much less heterochromatins than the other 2 forms. The Tall form possessed a pair of satellites which were found in orcein and CMA-staining. In DAPI staining, satellites showed negative banding which indicated its GC-rich nature. Satellite was not found in other 2 forms. Few chromosomes in the Typical and the Tall form fluoresced entirely with CMA. It indicated that these forms might have derived those chromosomes from a common ancestor. Due to the unique nature, those chromosomes could be used as marker. DAPI banded karyotypes showed similarities between the Typical form and the Slender form. It was much different in the Tall form. The overall karyotypic features indicated that the Tall form is quite different from the other 2 and thus it may be placed in different taxonomic rank. However, the Slender form may be considered as a trisomic variety of T. trilobatum (Typical form).