Tabebuia

In the tropics, seasonally flooded forests (SFF) harbor fewer tree species than terra firme (i.e. non-flooded) forests. The low species diversity of tropical flooded forests has been ascribed to the paucity of species with adaptations to tolerate flooding. To test the hypothesis that flooding is the only factor restricting most species from SFF, we compared plant morphological and physiological responses to flooding in 2-month old seedlings of 6 species common to SFF and 12 species common to terra firme forests. Although flooding impaired growth, total biomass, maximum root length and stomatal conductance in most species, responses varied greatly and were species-specific. For example, after 90 days, flooding reduced leaf area growth by 10–50% in all species, except in Tabebuia, a common species from non-flooded habitats. Similarly, flooding had a 5–45% negative effect on total biomass for all species, except in 1 SFF and 1 terra firme species both of which had more biomass under flooding. A principal component analysis, using the above responses to flooding, provided no evidence that SFF and terra firme species differed in their responses to flooding. Flooding also caused reductions in root growth for most species. Rooting depth and root: shoot ratios were significantly less affected by flooding in SFF than in terra firme species. Although flood tolerance is critical for survival in flooded habitats, we hypothesize that responses to post-flooding events such as drought might be equally important in seasonal habitats. Therefore, we suggest that the ability to grow roots under anoxia might be critical in predicting success in inundated habitats that also experience a strong dry season.

Traits associated with seed dispersal vary tremendously among sympatric wind-dispersed plants. We used two contrasting tropical tree species, seed traps, micrometeorology, and a mechanistic model to evaluate how variation in four key traits affects seed dispersal by wind. The conceptual framework of movement ecology, wherein external factors (wind) interact with internal factors (plant traits) that enable movement and determine when

ABSTRACT The circumscription of Bignoniaceae genera and tribes has undergone major changes following an increased understanding of phylogenetic relationships within the family. While DNA sequence data have repeatedly reconstructed major clades within the family, some of the clades recovered still lack diagnostic morpho-anatomical features, complicating their recognition. In this study we investigated the wood anatomy of all major lineages of Bignoniaceae (except Tourrettieae) in search for anatomical synapomorphies for clades. We sampled 158 species of Bignoniaceae, representing 67 out of the 82 genera currently recognized. Detailed descriptions of quantitative and qualitative wood anatomical features are presented for each clade and interpreted in the light of a molecular phylogeny for the family. Jacarandae are characterized by a paratracheal winged-aliform parenchyma, with the traditional subdivision of Jacaranda into sections Monolobos and Dilobos supported by the uniseriate and homocellular rays of Monolobos versus the wide and heterocellular rays of Dilobos. Tecomeae s.s. are characterized by scanty paratracheal parenchyma, septate fibers, and heterocellular rays, traits also found in Delostoma, a genus previously included in Tecomeae s.l., but recently shown to represent a separate lineage. Crescentiina includes two sub-clades, the Tabebuia alliance and the Paleotropical clade, which share abundant aliform parenchyma, short and mainly homocellular rays, less commonly with heterocellular rays with body procumbent and one row of marginal square cells. Members of the Tabebuia alliance and the Paleotropical clade can be distinguished from each other by the narrow vessels with a widespread storied structure found in members of the Tabebuia alliance, versus the vessels with medium to wide width and a non-storied structure found in members of the Paleotropical clade. Oroxyleae are characterized by a combination of simple and foraminate perforation plates and homocellular rays, while Catalpeae are characterized by scanty paratracheal parenchyma, abundant tyloses and vessel-ray pits simple to semi-bordered. Bignonieae differ from all other clades by a variant secondary growth and a typically lianoid wood anatomy. Overall, wood anatomical characters are not very labile within the family, being distributed across clades in a very predictive manner. Several anatomical characters represent good anatomical synapomorphies and provide further support to clades identified in molecular phylogenetic studies.

O curso de Formação Intelectual de Formadores Indígenas (FIEI), do Programa de Licenciaturas Indígenas (Prolind) do MEC, foi realizado na Universidade Federal de Minas Gerais (UFMG) em dez etapas presenciais, entre os anos de 2006 e 2011. Em cada etapa, foram convidados pesquisadores e educadores indígenas de todas as regiões do Brasil para atuarem como professores do Curso, trazendo para a comunidade universitária suas abordagens sobre os diversos temas estruturantes de cada etapa.Esta seção apresenta alguns desses pensamentos, através de suas palestras transcritas pelos monitores do eixo de Múltiplas Linguagens do FIEI e editadas por Mara Vanessa Dutra.Pensamento selvagem: jardim da biodiversidade.