Karyotype and RAPD analysis of three morphological forms of alocasia fornicata (Roxb.) Schott

Abstract

The three morphological forms based on leaf structure, viz. the Peltate leaf form, the Ovate-lanceolate leaf form, and the Sagittate leaf form, belonging to Alocasia fornicata (Roxb.) Schott were cytogenetically studied after differential staining with orcein, CMA, and DAPI. Moreover, molecular analysis using RAPD was also undertaken. The three specimens were found to possess 2n=28 chromosomes. The centromeric formula was 12m+16sm in the Peltate leaf form, 22m+6sm in the Ovate-lanceolate leaf form, and 18m+10sm in the Sagittate leaf form. Different CMA- and DAPI banding patterns were found in the Peltate leaf form and the Sagittate leaf form. No CMA- or DAPI band was found in the Ovate-lanceolate leaf form. Heteromorphicity in respect of CMA- and DAPI band indicated deletion of GC- and AT- rich repeats from the respective homologue members of the Peltate and Sagittate leaf form. The Ovate-lanceolate leaf form was significantly different from the other two forms in respect of differential karyotype analysis. The satellite of the Sagittate leaf form and the Ovate-lanceolate leaf form showed preferential staining. Each form has a characteristic RAPD fingerprinting pattern. The Sagittate leaf form showed a number of different-sized unique RAPD fragments in different primer combinations and thus was placed in a different clade from the other two forms in the phylogenetic dendrogram. Therefore, each form could be characterized on the basis of karyotype and RAPD analysis. This information will be helpful in further elucidating the taxonomic rank of these three morphological forms of Alocasia fornicata (Roxb.) Schott. © 2013 The Japan Mendel Society.