Abstract

TAPIA-PASTRANA, Fernando. Cytogenetics of Calochortus barbatus (Liliaceae: Calochortoideae) of the Reserva Ecológica del Pedregal de San Ángel, Distrito Federal, Mexico. Rev. Mex. Biodiv. [online]. 2010, vol.81, n.3, pp.649-654. ISSN 2007-8706.

Meristematic root cells from seeds of individuals of Calochortus barbatus from Reserva Ecológica del Pedregal de San Ángel, Distrito Federal, Mexico were analyzed cytogenetically using a surface spreading and air-drying method. The chromosomal number, 2n = 4x = 36 (x = 9) was corroborated. The mitotic karyotype was established for the first time for this species as 14m + 22st. The asymmetric karyotype, which includes 4 small subtelocentric chromosomes bearing a secondary constriction with its corresponding satellites, allows to discard previous reports of chromosomal fragments. Total haploid chromosomal length (53.48 μm), chromosomal length range (1.85 - 4.27 μm) and the asymmetry index (T.F. % = 23.13) add new information on chromosome architecture. The role of intraspecific hybridization and autoploidy in shaping the karyotype of this species and the need of performing similar analyses in related species are discussed.

Keywords : autoploidy; Calochortus; spreading and air-drying; karyotype; satellites; intraspecific hibridization.

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