Time filter

Source Type

Pinto R.B.,University of Campinas | de Freitas Mansano V.,Institute Pesquisas Do Jardim Botanico Do Rio Of Janeiro | Torke B.M.,New York Botanical Garden | Forni-Martins E.R.,University of Campinas
Brittonia | Year: 2015

To assess the taxonomic utility of cytogenetic variation in the species-rich neotropical papilionoid legume genus Swartzia and to ascertain the importance of cytogenetic evolution in the diversification history of the genus, a variety of cytogenetic data—chromosome number, chromosome lengths, relative chromosome length, total chromatin length (TCL), CMA/DAPI and FISH—were collected for 19 taxa of Swartzia and for a single species of the related genus Ateleia. In the sampled species of Swartzia, chromosome counts yielded a diploid number of 2n=2x=26. However, both diploid and tetraploid (2n=4x=52) counts were obtained for S. leptopetala. The species of Swartzia presented small chromosomes (0.25μm to 1.41μm), with gradual length variation, furthermore, each of them had two sites of CMA+/DAPI- and two sites of 45S and 5S rDNA. Cytogenetic data for the morphologically anomalous species S. euxylophora convey its close relationship to other species of Swartzia. Ateleia ovata was found to differ from all of the sampled taxa of Swartzia in diploid chromosome number (2n =28). Taken together, these results constitute preliminary evidence for a strongly conserved karyotype pattern in Swartzia and in combination with previously published data suggest that karyological characters, while useful for characterizing the genus, are of limited taxonomic utility within Swartzia. We conclude that cytogenetic evolution involving changes in chromosome number has not figured prominently in the explosive diversification history of Swartzia. © 2015 The New York Botanical Garden

Scoles R.,Federal University of Para | Gribel R.,National Institute of Amazonian Research | Gribel R.,Institute Pesquisas Do Jardim Botanico Do Rio Of Janeiro
Forest Ecology and Management | Year: 2012

This study examined the harvest of nuts from Brazil nut trees (Bertholletia excelsa) in the valley of the Trombetas River, a 760-km tributary on the northern bank of the Amazon River in Pará state, Brazil. The region is characterised by old-growth forests dominated by Brazil nut trees. Demographic data were obtained from twenty-five 50-m × 1000-m transects with different harvest intensities (total area = 125. ha) established approximately along the trails used by Brazil nut harvesters. For each transect, correlations were calculated between regeneration indicators (seedling, sapling, and juvenile densities) and potential ecological and demographic variables. The Brazil nut populations in the region were characterised by a low proportion of juveniles (7.8% of trees had a 10 cm < diameter at breast height - DBH < 40 cm), a dominance of large trees (DBH > 100 cm), and a tendency towards old growth (25.5% of trees had a DBH > 160cm). There were no seedlings in 52% of the transects, and 80% of the transects had no saplings. The low regeneration levels observed were independent of both harvest intensity and the dispersive activity of agoutis. An analysis of the regeneration indicators and the possible explanatory variables showed that harvests were not responsible for the low regeneration levels observed in the region. Furthermore, in areas with shorter distances between the points of harvest and first transport, the densities of saplings and juveniles were greater. We conclude that the restrictions on Brazil nut harvesting that are intended to improve the regeneration of Brazil nut trees are of little or no value. We propose the implementation of compensatory measures involving local communities and the promotion of seedling enrichment in gaps, forest edges, and disturbed areas, with the goal of promoting the growth of new generations of Brazil nut trees in the region. © 2011 Elsevier B.V.

Temponi L.G.,West Parana State University | Coelho M.A.N.,Institute Pesquisas Do Jardim Botanico Do Rio Of Janeiro
Rodriguesia | Year: 2011

Two new species of Anthurium are described for Brazil, Anthurium cipoense Temponi endemic of the Serra do Cipó National Park, Minas Gerais and Anthurium polynervium Temponi & Nadruz, endemic to municipality of Santa Maria Madalena, Rio de Janeiro state. Both have restricted distributions and studies on their conservation are needed. Descriptions, illustrations and commentaries on geographic distribution, ecology, phenology and conservation status are provided for both species.

Yepes M.S.,National University of Colombia | de Carvalho Junior A.A.,Institute Pesquisas Do Jardim Botanico Do Rio Of Janeiro
Mycologia | Year: 2012

A new genus of rust fungi (Basidiomycota, Pucciniales), with species type Caetea itatiaiaensis, was collected on Piptadenia (Fabaceae) at the Parque Nacional do Itatiaia in the Serra da Mantiqueira, states of Rio de Janeiro and Minas Gerais, Brazil. This genus is delimited as (i) three-celled teliospores borne on a single pedicel each with a corresponding apical cell and (ii) apical cells giving rise to distally capitate cysts that overhang the teliospore cells. © 2012 by The Mycological Society of America.

Scoles R.,Federal University of Para | Gribel R.,National Institute of Amazonian Research | Gribel R.,Institute Pesquisas Do Jardim Botanico Do Rio Of Janeiro
Human Ecology | Year: 2011

Here we hypothesize that the intensity of disturbances caused by human activities in Brazil nut stands (castanhais) is positively related with the regeneration of Brazil nut trees (Bertholletia excelsa H. B. K., Lecythidaceae) and consequently with a younger population structure of this species. In order to test this hypothesis we compared the population structure of Brazil nut trees in two areas of the Brazilian Amazon with different histories of land usage by humans. Archeological and historical data suggest that the region surrounding the Trombetas River was densely occupied in pre-Columbian times and experienced depopulation after European contact with Amerindian populations, especially in the 16 th century. The 25 Brazil nut stands sampled in this region were dominated by old B. excelsa trees and had scarce recruitment in the understory. These very mature stands likely owe their origins to the interval between the depopulation of the indigenous peoples in the 16 th-17 th centuries and the establishment of quilombos at the beginning of the 19 th century. The second study area was in the vicinity of the Madeira River (Capanã Grande Lake), where the castanhais were more accessible and disturbed. In this site, a younger population structure and abundant regeneration of B. excelsa were observed in the 10 sampled stands. Historical data from this region indicate that indigenous populations were replaced gradually beginning in the 18 th century, with no evidence of severe depopulation. We suggest that the different historical and contemporary land use patterns contributed to the current contrasting population structures of the castanhais at the two locations. The data also support the idea that the castanhais, even the ones considered to be pristine and "native" forests, result from anthropogenic influences. We found no evidence to support restrictions on seed harvesting as a means to improve regeneration rates of Brazil nut stands. © 2011 Springer Science+Business Media, LLC.

Discover hidden collaborations