RESUMO
Neste trabalho foi feita a caracterização citogenética da: microsporogênese, tétrades, estimativa da viabilidade do pólen pelo método de coloração e contagem do número máximo de nucléolos por célula interfásica, para identificação dos níveis de ploidia, em cinco espécies do gênero Mentha L. Foram coletadas inflorescências em 30 plantas de cada espécie, em duas florações sucessivas, nos anos 2006 e 2007. As inflorescências foram tratadas em etanol-ácido acético (3:1), em temperatura ambiente durante seis horas, transferidas para álcool 70% (v/v) e conservadas em geladeira até análise. Nas análises da microsporogênese, tétrades e pólen o corante usado foi carmin propiônico 2% e na identificação dos nucléolos nitrato de prata (AgNO3). Os resultados demonstraram que as cinco espécies são poliplóides. M. crispa heptaplóide (2n=7x=84) com 11 nucléolos, M. spicata tetraplóide (2n=4x=48) com 8 nucléolos, M.x gentilis pentaplóide (2n=5x=60) com 12 nucleólos, M. piperita e M.x piperita ambas hexaplóides (2n=6x=72) com 8 e 9 nucléolos respectivamente. M. spicata e M. crispa mantiveram as mais altas porcentagens de células normais na microsporogênese, na formação de tétrades e na estimativa da viabilidade do pólen por coloração, sugerindo maior estabilidade meiótica quando comparados aos demais poliplóides estudados.
The cytogenetic characterization of five species of Mentha L. genus, including the data: regularity of microsporogenesis and tetrads, and polen viability, using the coloration method and the counting of the maximum number of nucleolus by interphasic cell were carried out in this study to identify the ploid levels. These analyses were performed from inflorescences collected in 30 plants of each species, during two successive florations in 2006 and 2007. Inflorescences were treated in 3:1 ethanol:acetic acid mixture at room temperature during six hours, then transferred to 70%(v/v) ethanol solution and refrigerated until the analysis. For microsporogenis, tetrad and pollen analysis, we used carmine propionic 2% (m/v) and for nucleolus identification, we used AgNO3 solution. It was possible to observe that all five species were polyploids. M. crispa heptaploid (2n=7x=84) with 11 nucleolus, M. spicata tetraploid (2n=4x=48) with 8 nucleolus, M. x gentilis pentaploid (2n=5x=60) with 12 nucleolus, M. piperita and M. x piperita both hexaploid (2n=6x=72) with 8 and 9 nucleolus respectively. M. spicata and M. crispa kept the highest percentual values of normal cells in microsporogenesis as well as in tetrads formation and pollen viability, suggesting a higher meiotic stability when compared to the other polyploids studied.
Assuntos
Poliploidia , Mentha/metabolismo , Plantas Medicinais/classificação , Cromossomos , Citogenética/instrumentaçãoRESUMO
The objective of this experiment was to determine the flow characteristics of a hemoperfusion device. The standard device consists of a cylindrical container which is tapered towards the outlet end. Flow enters the column through a small inlet tube into the wide frontal area of the column. Having passed through the column containing collodian coated activated charcoal spheres, it leaves by the tapered outlet. In order to achieve our aim, we designed and built a two-dimensional plexiglass model consisting of a vertical cross section of the actual hemoperfusion device. Glass beads were used to simulate the artificial carbon cells and a colored solution was used to enable us to visualize the flow. In the normal configuration, it was determined that stagnation and channelling were present. The model was then analysed in the inverse configuration. This way, flow inlet is through the tapered end and flow outlet is towards the wider cylindrical end. This inverse flow configuration improved the flow characteristics and eliminated most of the channelling and stagnation.
