Karyological characterization of Butia (Arecaceae) palm trees.
Butiá is a native fruit which is a lot used in the Southern of Brazil and it is usually harvested like crop fruit. Five species of native palm trees of the genus Butia occur in Rio Grande do Sul state, Brazil. Chromosome numbers and karyotype of Butia eriospatha and B. odorata are being reported for the first time. B. capitata and B. yatay had the chromosome numbers previously described, although its karyotype has never been reported before and B. paraguayensis coincided not with the early count. Fruits from natural populations were collected; the seeds were extracted and put to germinate. The aim of this paper was to analyze the chromosomical features between and into five species of this genus. Nine specimens of B. capitata, three of B. eriospatha, three of B. odorata, two of B. paraguayensis and two of B. yatay were analyzed. Root tips from seedlings were pretreated in 0.002 M 8-hydroxyquinoline or icy water (0°C) or 1% colchicine, fixed in ethanol and acetic acid (3:1) and then stained in 2% Giemsa. All species showed the same chromosome number, 2n=2x=32, and the same chromosome morphology: 14 metacentric, 12 submetacentric and 6 acrocentric chromosomes. Karyotypes of all species are symmetric, with two pairs of satellite, one pair of metacentric and one pair of acrocentric chromosomes.