Karyomorphological studies in Mucuna of India

Abstract

Mucuna Adans. is a large genus with more than 150 species of annual and perennial legumes of pantropical distribution. Despite considerable economic importance of some of its species, almost no work has been done on their cytogenetic characterization in any part of World. In this paper, we have presented a first report on karyomorphological analysis in four Indian species viz., Mucuna atropurpurea, Mucuna monosperma, Mucuna nigricans and Mucuna pruriens bringing out diploid number for M. atropurpurea and karyotypic formula for all the four species. Root tips were treated with 0.002 M 8-hydroxyquinoline and temporary preparations were made after squash in aceto-carmine. Karyomorphological description for each of the species has been detailed taking into account the following features: chromosome number, total length and relative length, arm ratio of each chromosome, haploid set length and degree of asymmetry. Mitotic metaphases in all the species showed 2n=22 chromosomes. Mucuna nigricans showed two pairs of sat-chromosomes. None of the species, however, revealed identical karyotypic formula indicating occurrence of rearrangements. The haploid set length of annual M. pruriens was found to be reduced in size when compared to perennial species pointing its evolution from the latter.