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Analysis of the germination rate, mitotic index and karyotype of Chromolaena barranquillensis (Hieron.) R.M. King & H. Rob.—Asteraceae

2014; Elsevier BV; Volume: 94; Linguagem: Inglês

10.1016/j.sajb.2014.06.012

1727-9321

Juan D. Rodríguez, Amner Muñoz-Acevedo, A.L. Méndez, R. Jiménez, Rebeca Gutiérrez,

Plant tissue culture and regeneration

Chromolaena barranquillensis (Asteraceae) is an endemic plant of northern Colombia that has garnered economic and medicinal interest, because species from the genus Chromolaena have shown diverse biological activities. This study describes, for the first time, the karyotype, germination and mitotic indices of C. barranquillensis (Hieron.) R.M. King & H. Rob. The germination index was between 34% and 56% with an average germination rate of 1.2 ± 0.4 seeds/day. The mitotic index analysis allowed to determine the cell cycle time (4 h, 10 min) and the mitotic hours (3:00–8:00 h and 17:00 h). The mitosis time was 49 min, equivalent to ~ 20% of the cell cycle. Karyotype analysis showed that C. barranquillensis is a hexaploid species with a chromosomal formula 2n = 6x = 60 = 48 m + 12 sm, and the average chromosomal lengths were 1.7 ± 0.1 μm to 0.9 ± 0.3 μm. The Stebbins asymmetry index was 2B, and the total form percentage was ~ 41%. These results uncover differences between C. barranquillensis and Chromolaena odorata, one of the most abundant species found in the world and the most closely related species to C. barranquillensis.