Plant Biol (Stuttg) 2006; 8(4): 486-493
DOI: 10.1055/s-2006-923859
Research Paper

Georg Thieme Verlag Stuttgart KG · New York

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

F. Chiarini1 , G. Bernardello1
  • 1Instituto Multidisciplinario de Biología Vegetal (CONICET‐UNC), C.C. 495, 5000 Córdoba, Argentina
Further Information

Publication History

Received: November 18, 2005

Accepted: December 29, 2005

Publication Date:
11 May 2006 (online)

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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.

References

F. Chiarini

Instituto Multidisciplinario de Biología Vegetal (CONICET‐UNC)

C.C. 495

5000 Córdoba

Argentina

Email: chiarini@imbiv.unc.edu.ar

Editor: F. Salamini