Karyotype studies in Mimosa (Mimosoideae, Leguminosae) fromSouthern South America and ecological and taxonomic relationships

MORALES, M.; WULFF, A.; FORTUNATO RENÉE H.; POGGIO, L.

CARYOLOGIA

UNIV FLORENCE BOTANY INST

Año: 2011 vol. 64 p. 201 - 212

0008-7114

In this work we studied the chromosome number and karyotype formula of seven species of Mimosa L. (Mimosoideae, Leguminosae). The chromosome number 2n = 2x = 26 for M. detinens Benth., M. hexandra M. Micheli, M. ostenii Speg. ex Burkart and M. xanthocentra Mart. var. mansii (Benth.) Barneby are new records, while the chromosome number 2n = 2x = 26 for M. debilis var. debilis, M. urugüensis Hook. and Arn. and M. uliginosa Chodat and Hassl. confi rm previous records. Karyotype formulae revealed the existence of metacentric and submetacentric chromosomes, and the chromosomal asymmetry indexes did not show significant differences between taxa. The chromosome length of xerophilous and endemic M. detinens and M. ostenii differed from the rest of species, indicating that this parameter could have taxonomic value. In addition, the relationship between total chromosome length and climatic parameters showed that diploid species of marginal areas of distribution have a larger chromosome size, and that this could be related with mechanisms of ecological adaptation.