Karyotype Studies in South American Species of Solanum subgen. Leptostemonum (Solanaceae)

Abstract

Mitotic chromosome numbers and karyotypes of 13 South American species (12 native and one naturalized) from four sections of SOLANUM subgen. LEPTOSTEMONUM were studied. Chromosome numbers of S. ACERIFOLIUM, S. AENICTUM, S. CONDITUM, S. CONSIMILE, S. INCARCERATUM, and S. PLATENSE are reported for the first time. The number 2n = 24 was found in most species, while 2n = 22 was found in S. MAMMOSUM and S. PLATENSE. The latter is the second SOLANUM with this unusual number. Satellites are always present and were visible in more than 50 % of the cells studied. Karyotypes are symmetrical: M and SM chromosomes are common, whereas ST chromosomes are rare. The karyotypes of S. AENICTUM, S. MAMMOSUM, and S. PANICULATUM are comparatively asymmetrical. Species can be distinguished by a combination of chromosome number, karyotype formulae, karyotype length, the position of satellites in a particular chromosome pair, and asymmetry indices. The phenogram obtained does not reflect the sectional arrangements or the systematic affinities of the species studied. In sect. ACANTHOPHORA, increased asymmetry is associated with derived characters (strong andromonoecy, winged seeds, mammiform fruits). Diversification in the subgenus is suggested to be related to visible chromosome rearrangements and cumulative, cryptic structural changes may have also played a relevant evolutionary role.

Karyotypes of South American species of the Morelloid and Dulcamaroid clades (Solanum, Solanaceae)

“…Acosta and Moscone 2000;Hunziker 2001;Acosta et al 2005Acosta et al , 2012. A few exceptions have been detected in Solanum within the Leptostemonum clade (S. mamosum and S. platense with n = 22; Chiarini and Bernardello 2006) and the Archaesolanum clade (seven species with n = 23; Pinto Maggio et al 1997).…”

“…However, the karyology of less than half of Solanum species has been studied (Hunziker 2001). Karyotypes have been reported for several American species of Solanum and have proved to be useful in differentiating taxa and evolutionary trends; for instance, Basarthrum (Bernardello and Anderson 1990), Lasiocarpa (Bernardello et al 1994), Leptostemonum (Chiarini and Bernardello 2006), and Solanum as a whole (e.g. Acosta et al 2005Acosta et al , 2012Rego et al 2009;Chiarini et al 2010;Melo et al 2011).…”

Karyotype analysis in two species ofSolanum(Solanaceae) Sect.Cyphomandropsisbased on chromosome banding

“…The most consistent morphological synapomorphies of the group are the presence of big chromosomes (4 mm long) and large amounts of nuclear DNA, which have been found in all the species of the clade analysed to date (Roe 1967;Pringle & Murray 1991, 1993Moscone 1992;Bennett & Leitch 2010). These characteristics separate these species from other members of Solanum, which have smaller chromosomes (B 4 mm) and a lower nuclear DNA content (Bernardello & Anderson 1990;Bernardello et al 1994;Acosta et al 2005;Chiarini & Bernardello 2006;Rego et al 2009;Bennett & Leitch 2010;Melo et al 2011).…”

“…These characteristics separate them from the remaining Solanum sections, which exhibit smaller chromosomes and lower DNA content (cf. Bernardello & Anderson 1990;Bernardello et al 1994;Acosta et al 2005;Chiarini & Bernardello 2006;Rego et al 2009;Bennett & Leitch 2010;Melo et al 2011).…”

Estudo citogenético e evolutivo em espécies brasileiras de Eleocharis (Cyperaceae)

“…The karyotype differentiation in E. maculosa was studied using conventional staining (mi- Some plant groups exhibit seemingly conserved karyotypes, with chromosome number, shape and size relatively constant when these are studied by conventional cytogenetics. A good example is the relative similarity among karyotypes of different species of Lobelia, Campanulaceae (Ruas et al, 2001), and Solanum, Solanaceae (Chiarini and Bernardello, 2006). However, in the family Cyperaceae, intraand interspecific karyotype variations associated with chromosome number and size are very common.…”