Karyomorphometry on three polyploid species of Arum L. (Araceae, Aroideae)

Abstract

In this study three polyploid Arum Linnaeus, 1753 species from Southern Italy were chromosomally investigated. Arum italicum Miller, 1768 was found to have 2n = 84 chromosomes and a karyotype composed of numerous asymmetric chromosomes. Arum maculatum Linnaeus, 1753 and A. apulum (Carano) P. C. Boyce, 1993 were found to have 2n = 56 chromosomes. In the examined taxa some chromosome pairs were characterized by the presence of weakly coloured Feulgen-stained segments. The karyotype morphology of A. italicum was found to be similar to that of A. maculatum, but the more asymmetrical karyotype and numerous weakly coloured Feulgen-stained segments observed in the former suggest the existence of more extensive rearrangements. In contrast, A. apulum was observed to have a symmetrical karyotype. The A1, A2 and SYi karyotype asymmetry indices are presented. The relationships between these taxa in terms of karyotype morphology and evolution are discussed.