783 research outputs found
Micropropagation of Alibertia edulis Rich
The aim of this work was to develop a micropropagation protocol for Alibertia edulis, a medicinal Brazilian
Cerrado plant. A. edulis seeds were sterilized and germinated in water-agar. Fifteen millimeter long explants from
the seedlings cultivated for 50 days were used for the multiplication in three consecutive subcultures. The cytokinin
benzyladenine (BA) alone or combined with indole-3-butyric acid (IBA) was added to ¼ MS medium. The treatments
containing combinations of the BA + IBA induced more shoot proliferation than the BA alone, with the optimum
concentration of 0.5 mg.L-1 for both growth regulators. A. edulis shoots elongated easily and the presence of growth
regulators did have a positive effect on the shoot elongation. Consecutive subcultures also had a positive effect on
both sprouting and shoot elongation. Activated charcoal was essential for rooting, and all rooted plants were able
to acclimatize
Estructura de la semilla y desarrollo inicial de Byrsonima basiloba Juss. (Malpighiaceae)
Byrsonima basiloba Juss. is a fast growing shrub that produces edible and juicy fruits. This research studied the morphology and anatomy of seeds and seedlings. The hard endocarp was crested and triloculate, with one seed per locule. B. basiloba seed was composed of a testa and a tegmen with residual endosperm. The embryo was ivory, with long, foliaceous, circinate, anisophyllous cotyledons with disjointed apices. The embryonary axis was short, straight and occupied a small portion of the seed with short epicotyl, and radicle with a rudimentary root cap. In the seedlings, it was possible to differentiate the protoderm, procambium and ground meristem in the elongation zone. The differentiation process in this species occurred early in the embryo. Leaf primordia surrounded the shoot apical meristem, which contained a developing parenchyma, epidermis with trichomes, and the vascular system already partially differentiated, with xylem vessels with helical thickening. The stem/root transition region, which originated the xylopodium in the adult plant, was oblique to the stem axis. Cotyledons and eophylls were amphistomatic. The anatomical description can help with taxonomic identification of the species in the field, as well as to provide a guide to choosing explants for in vitro cultivation protocols.Byrsonima basiloba Juss. es un arbusto de rápido crecimiento que produce frutos comestibles y jugosos. Esta investigación estudió la morfología y anatomía de las semillas y plantas jóvenes de este arbusto. Su endocarpio duro contiene una semilla por lóculo. La semilla está compuesta por una testa y un tegumento con un endospermo residual. El embrión es de color marfil, con cotiledones largos circinados, anisófilos, foliáceas con ápices inconexos. El eje embrionario es corto, recto, con epicotilo corto y radícula, y con una tapa de raíz rudimentaria, y ocupa una pequeña porción de la semilla. En la plántula es posible diferenciar claramente la protoderma del procambium y del meristema primario. Inmediatamente por encima del promeristema se encuentran el parénquima cortical, la epidermis con pelo, y el cilindro vascular ya parcialmente diferenciado, así como los vasos del xilema con engrosamiento helicoidal, por lo que se puede concluir que la diferenciación de los tejidos de esta especie se produce muy temprano. La región de cuello, que se origina del xilopodium en la planta adulta, no muestra ningún cambio en el color, siendo oblicua al eje del vástago. Los cotiledones y eófilos son anfistomáticos. La descripción anatómica puede ayudar con la identificación taxonómica de las especies, como también proporcionar una guía para el futuro, en cuanto a protocolos de cultivo in vitro
Comparative wood and bark anatomy of stem, root and xylopodium of Jacaranda ulei (Bignoniaceae)
Jacaranda ulei is a common shrub from Cerrado that presents medicinal properties. Aerial stem is not resistant to the naturally recurrent fire of this ecosystem. The plants re-sprout via the xylopodium. This paper compares the anatomical structures of the wood and the bark of the root, the stem, and the xylopodium. A sample of five individuals of Jacaranda ulei was processed using usual techniques. In common, the wood is diffuse porous and the axial parenchyma is confluent and vasicentric, but there are clear differences among the root, the stem and the xylopodium. The bark is thin, with gradual transition seen between the conducting and the nonconducting phloem, and with groups of fibers and sclereids. In the stem, the fibers are arranged in bundles and the periderm presents hairs. In the subterranean organs, the sclerenchymatic tissue is arranged in concentric lines and secretory canals were seen. Such differences are probably related to the different functions of aerial and subterranean organs
II Diretriz Brasileira de Transplante Cardíaco
Universidade de São Paulo Faculdade de Medicina Hospital das ClínicasIIHospital de Messejana Dr. Carlos Alberto Studart GomesUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaInstituto Dante Pazzanese de CardiologiaUniversidade Federal de Minas Gerais Hospital das ClínicasFaculdade de Medicina de São José do Rio PretoPontifícia Universidade Católica do ParanáIHospital Israelita Albert EinsteinInstituto Nacional de Cardiologia, Fundação Universitária do Rio Grande do Sul Instituto de CardiologiaReal e Benemérita Sociedade de Beneficência Portuguesa, São PauloHospital Pró-Cardíaco do Rio de JaneiroSanta Casa do Rio de JaneiroUNIFESP, EPMSciEL
Geography and ecology shape the phylogenetic composition of Amazonian tree communities
Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.
Location: Amazonia.
Taxon: Angiosperms (Magnoliids; Monocots; Eudicots).
Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran\u27s eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.
Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.
Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis).
Time period: Tree-inventory plots established between 1934 and 2019.
Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm.
Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield.
Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes.
Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests.
Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types
Geography and ecology shape the phylogenetic composition of Amazonian tree communities
AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
The biogeography of the Amazonian tree flora
We describe the geographical variation in tree species composition across Amazonian forests and show how environmental conditions are associated with species turnover. Our analyses are based on 2023 forest inventory plots (1 ha) that provide abundance data for a total of 5188 tree species. Withinplot species composition reflected both local environmental conditions (especially soil nutrients and hydrology) and geographical regions. A broader-scale view of species turnover was obtained by interpolating the relative tree species abundances over Amazonia into 47,441 0.1-degree grid cells. Two main dimensions of spatial change in tree species composition were identified. The first was a gradient between western Amazonia at the Andean forelands (with young geology and relatively nutrient-rich soils) and central–eastern Amazonia associated with the Guiana and Brazilian Shields (with more ancient geology and poor soils). The second gradient was between the wet forests of the northwest and the drier forests in southern Amazonia. Isolines linking cells of similar composition crossed major Amazonian rivers, suggesting that tree species distributions are not limited by rivers. Even though some areas of relatively sharp species turnover were identified, mostly the tree species composition changed gradually over large extents, which does not support delimiting clear discrete
biogeographic regions within Amazonia
- …