Comparison of Orcein and CMA Stained Karyotypes in Three Morphological Forms of Typhonium trilobatum L. (Araceae)

Abstract

The karyotypes in 3 morphological forms of Typhonium trilobatum (L.) Schott such as the Green form, the Dark purple form and the Light purple form were compared after staining with orcein and CMA. The Green form and the Light purple form were found to possess 2n =18 chromosomes. However, 2n =17 chromosomes were observed in the Dark purple form. One chromosome in pair IX was absent in this form. The karyotypic features revealed that the Dark purple form might be originated from the Green form as monosomic. The centromeric formula was determined 16m+2ac in the Green form, 11m+4sm+2ac in the Dark purple form and 13m+5sm in the Light purple form. The Dark purple form showed more heterogeneous karyotype and may be considered as more advanced than the other 2 forms. No CMA band was found in the Green form. The Dark purple and the Light purple forms were found to possess distinct CMA banding pattern. With the help of CMA banding, it was possible to identify some chromosomes in these 2 forms. Few chromosome pairs in both the forms showed heteromorphicity in respect of CMA banding pattern indicating the occurrence of structural aberration. Morphology, distinct karyotypic features and CMA banding pattern suggested for placing the Green form in different taxonomic rank, while the Dark purple form might be considered as a monosomic variety of Typhonium trilobatum.