RESUMO
Lychnophora ericoides and Lychnophora pinaster are species used in popular medicine as analgesic or anti-inflammatory agents to treat contusions, rheumatism, and insect bites. In this study, 21 simple sequence repeat loci of L. ericoides were developed and transferred to L. pinaster. Three populations of L. ericoides and 2 populations of L. pinaster were evaluated; they were collected in the State of Minas Gerais. Population parameters were estimated, and the mean values of observed and expected heterozygosity were 0.297 and 0.408 (L. ericoides) and 0.228 and 0.310 (L. pinaster), respectively. Greater genetic variability was observed within populations than between populations of L. ericoides (62 and 37%) and L. pinaster (97 and 2.8%). These results provide information for genetic conservation and taxonomic studies of these endangered species.
Assuntos
Arnica/classificação , Arnica/genética , Repetições de Microssatélites , Brasil , DNA de Plantas/genética , Espécies em Perigo de Extinção , Variação Genética , Folhas de Planta/genética , Plantas Medicinais/classificação , Plantas Medicinais/genética , Análise de Sequência de DNARESUMO
In order to extend our knowledge concerning karyotypes of the genus Vernonia, we applied various techniques of chromosome banding, including AgNOR and triple staining with the fluorochromes CMA/DA/DAPI (CDD), and of fluorescent in situ hybridization (FISH) for the 45S rDNA probe to specimens of two populations of Vernonia geminata collected from an open-pasture area, in southern Brazil. B chromosomes were observed in one of the populations. Both populations of V. geminata presented a pair of CMA(3)(+) terminal bands and one pair of chromosomes with terminal AgNOR banding. The FISH evidenced, in one population, two pairs of small sites of 45S rDNA; these being two small terminal sites and two centromeric sites. In the other population, there was only one pair of small terminal sites and two sites in two B chromosomes, one in each chromosome. There was coincidence of localization between CMA(+) and NOR bands with one of the small terminal sites of 45S rDNA of one chromosome of the normal complement, but not in B chromosomes.
Assuntos
Cariótipo , Vernonia/genética , Bandeamento Cromossômico , Cromossomos de Plantas/genética , DNA Ribossômico/genética , Corantes Fluorescentes/química , Genes de Plantas , Hibridização in Situ Fluorescente , Indóis/química , Coloração pela PrataRESUMO
We conducted an isozyme study in 22 populations of five Pleurothallis (Orchidaceae) species (12 loci in nine enzymatic systems). The genetic variability in all populations is surprisingly high (P = 58-83%, A = 2.1-3.8, H(e) = 0.25-0.43) in spite of the fact that the five species are pollinated by small flies whose behavior enables self-pollination. We suggest that self-incompatibility, inbreeding depression, and mechanical barriers that prevent self-pollination in these species are responsible for the maintainance of the high genetic variability. These traits are uncommon in Orchidaceae, but have been observed in these and some other species pollinated by flies or other pollinators with behavior that facilitates self-pollination. The genetic similarity among conspecific populations is also high for species with very short-range flying pollinators. Only one population of P. teres presented values of genetic similarity lower than usually observed in allopatric conspecific populations. Morphology, however, does not support its segregation as a new taxon. All species can be recognized by their enzymatic patterns, and the results agree with recently proposed taxonomic realignments. Conversely, the supposed affinities among these species based on floral morphology are not supported, and we hypothesize that it may be due to convergence in species with similar pollinators.
RESUMO
The alkaloids of leaves and flowers of 18 populations of four Pleurothallis (Orchidaceae) species were characterized. Both leaves and flowers of individuals from all populations have two diasteroisomers of 1-hydroxymethylpyrrolizidine (RI=1290 and 1311). The 1290 isomer was the most abundant in all populations of P. johannensis (74-93%) and P. fabiobarrosii (63-93%), two morphologically closed species. On the other hand, in almost all populations of P. teres the 1311 isomer is the more abundant (61-95%), except in one population occurring disjunct from the core area distribution of the species. These results support the recent taxonomic revision for these three species. Almost all P. ochreata populations also have the 1290 as the most abundant isomer, except in one morphologically differentiated population situated at the southern extreme of the distribution of this species.
