Karyological investigation of Calotropis gigantea (L.) W. T. Aiton and Centella asiatica (L.) Urban: Two important medicinal plants of Bangladesh

Calotropis gigantea (L.) W. T. Aiton and Centella asiatica (L.) Urban have been medicinally used throughout Bangladesh. In this study, karyotypic features of these two species were studied with orcein staining and banding with two base specific fluorochromes such as chromomycine A(3) (CMA) and 4', 6 diamidino-2-phenylindole (DAPI) for authentic cytogenetical characterization. 2n = 22 and 2n = 18 somatic chromosomes were found in C. gigantea and C. asiatica, respectively. The total chromosome length of C. gigantea and C. asiatica were 45.35 +/- 2.64 mu m and 63.63 +/- 3.19 mu m, respectively. The total form percent (TF%), karyotype asymmetry index (AsK%) and karyotype symmetry index (Syi index) were 47.61, 52.39 and 90.87 in C. gigantea and 39.58, 60.42 and 65.51 in C. asiatica, respectively. Both species were found to possess 1A karyotype. In C. gigantea, 2 CMA- and 4 DAPI-bands were observed whereas C. asiatica had 16 CMA- and 6 DAPI-bands. Therefore, the compiled data generated from chromosome analysis on orcein, CMA- and DAPI-banding will be useful for cytogenetical characterization of these two species.