INVESTIGADORES
FORTUNATO Renee Hersilia
artículos
Título:
Chromosome studies in southern species of Mimosa (Fabaceae)
Autor/es:
MORALES, M.; WULFF, A.; FORTUNATO, R.H.; POGGIO, L.
Revista:
PLANT SYSTEMATICS AND EVOLUTION
Editorial:
SPRINGER WIEN
Referencias:
Lugar: Viena; Año: 2013
ISSN:
0378-2697
Resumen:
In this work, chromosome numbers and
karyotype parameters of 36 taxa of the genus Mimosa were
studied, especially from the southern South America center
of diversification. Results support that x = 13 is the basic
chromosome number in the genus. Polyploidy is very frequent,
ca. 56 % of the total of the studied species here are
polyploid, confirming that polyploids are more frequent at
higher latitudes. The most common ploidy levels found are
2x and 4x, but some species studied exhibit 6x and 8x. In
different groups, several ploidy levels were found.
Parameters of chromosome size show statistically significant
differences between close species, and asymmetry
index A2 exhibited low variation between them. It is possible
to infer variations of chromosome size between diploids
and tetraploids and between basal and derived taxa.
The present studies confirm or reveal polyploidy in several
groups of South America which are highly diversified in
the southernmost area of distribution of the genus, such as
sect. Batocaulon ser. Stipellares and sect. Calothamnos.
Our data are discussed in a taxonomic context, making
inferences about the origin of some polyploid taxa. Polyploidy
could be an important phenomenon that increases
the morphologic diversity and specific richness in southern
South America. On basis of our data, it is possible to
hypothesize hybridization between same-ploidy level or
different ploidy level taxa. As already shown in the literature,
our results confirm the importance of the polyploidy
in the speciation of the genus.