Molecular phylogeny and evolution of inflorescence types in Eperua.

PREMISE: The Amazonian hyperdominant genus Eperua (Fabaceae) currently holds 20 described species and has two strongly different inflorescence and flower types, with corresponding different pollination syndrome. The evolution of these vastly different inflorescence types within this genus was unknown and the main topic in this study. METHODS: We constructed a molecular phylogeny, based on the full nuclear ribosomal DNA and partial plastome, using Bayesian inference and maximum likelihood methods, to test whether the genus is monophyletic, whether all species are monophyletic and if the shift from bat to bee pollination (or vice versa) occurred once in this genus. RESULTS: All but two species are well supported by the nuclear ribosomal phylogeny. The plastome phylogeny, however, shows a strong geographic signal suggesting strong local hybridization or chloroplast capture, rendering chloroplast barcodes meaningless in this genus. CONCLUSIONS: With our data, we cannot fully resolve the backbone of the tree to clarify sister genera relationships and confirm monophyly of the genus Eperua. Within the genus, the shift from bat to bee and bee to bat pollination has occurred several times but, with the bee to bat not always leading to a pendant inflorescence.

Highly local environmental variability promotes intrapopulation divergence of quantitative traits: an example from tropical rain forest trees.

BACKGROUND AND AIMS: In habitat mosaics, plant populations face environmental heterogeneity over short geographical distances. Such steep environmental gradients can induce ecological divergence. Lowland rainforests of the Guiana Shield are characterized by sharp, short-distance environmental variations related to topography and soil characteristics (from waterlogged bottomlands on hydromorphic soils to well-drained terra firme on ferralitic soils). Continuous plant populations distributed along such gradients are an interesting system to study intrapopulation divergence at highly local scales. This study tested (1) whether conspecific populations growing in different habitats diverge at functional traits, and (2) whether they diverge in the same way as congeneric species having different habitat preferences. METHODS: Phenotypic differentiation was studied within continuous populations occupying different habitats for two congeneric, sympatric, and ecologically divergent tree species (Eperua falcata and E. grandiflora, Fabaceae). Over 3000 seeds collected from three habitats were germinated and grown in a common garden experiment, and 23 morphological, biomass, resource allocation and physiological traits were measured. KEY RESULTS: In both species, seedling populations native of different habitats displayed phenotypic divergence for several traits (including seedling growth, biomass allocation, leaf chemistry, photosynthesis and carbon isotope composition). This may occur through heritable genetic variation or other maternally inherited effects. For a sub-set of traits, the intraspecific divergence associated with environmental variation coincided with interspecific divergence. CONCLUSIONS: The results indicate that mother trees from different habitats transmit divergent trait values to their progeny, and suggest that local environmental variation selects for different trait optima even at a very local spatial scale. Traits for which differentiation within species follows the same pattern as differentiation between species indicate that the same ecological processes underlie intra- and interspecific variation.

Biological Activities and Cytotoxicity of Eperua oleifera Ducke Oil-resin.

BACKGROUND: The oil-resin of Eperua oleifera Ducke has been used in popular medicine similarly to the copaiba oil (Copaifera spp.). OBJECTIVE: This study aimed to investigate the effects of the acid fraction of E. oleifera oil-resin (AFEOR) on cell proliferation, collagen production in human fibroblasts, inhibition of metalloproteinases, and cytotoxicity against tumor cell lines. MATERIALS AND METHODS: Acid fraction of E. oleifera was fractionated in the ion exchange column chromatography. Cytotoxicity and genotoxicity were evaluated by Alamar Blue® and Cometa assay. The inhibition of metalloproteinases was performed by zymography and Western blotting. RESULTS: The predominant acidic diterpenes in the AFEOR were copalic and hardwickiic acids. AFEOR caused morphology alteration and decrease of proliferation at concentrations higher than 5 µg/mL. It also caused significant collagen proliferation in fibroblasts. It showed cytotoxicity against tumoral and nontumoral cell lines, with IC50 values ranging from 13 to 50 µg/mL, and a hemolytic activity with an IC50 value of 38.29 µg/mL. AFEOR inhibited collagenase activity, with an IC50 value of 46.64 µg/mL, and matrix metalloproteinase-2 (MMP)-2 and MMP-9 in HaCaT cells or MMP-1 expression in MRC-5 cells. AFEOR induced genotoxicity in MRC-5 cells with a DNA damage index between 40% and 60% when compared to the negative controls (0%-20%). CONCLUSION: For the first time, biological activities from oil-resin E. oleifera demonstrated ratifying somehow its popular use. SUMMARY: Analysis of crude oil-resin and fractionation of diterpenic fraction was performance using selective ion-exchange column chromatographyCytotoxicity analysis and morphology were performed with different cell linesCollagen production in human fibroblasts, inhibition of metalloproteinases were demonstrated by zymography and Western blotting. Abbreviations used: AFEOR: Eperua oleifera oil-resin.

Contrasting responses to mycorrhizal inoculation and phosphorus availability in seedlings of two tropical rainforest tree species.

• This work aimed at understanding the role of mycorrhizal status in phosphorus efficiency of tree seedlings in the tropical rainforest of French Guyana. • Mycorrhizal colonization, growth, phosphorus content, net photosynthesis and root respiration were determined on three occasions during a 9-month growth period for seedlings of two co-occurring species (Dicorynia guianensis and Eperua falcata) grown at three soil phosphorus concentrations, with or without inoculation with arbuscular mycorrhizas. • Seedlings of both species were unable to absorb phosphorus in the absence of mycorrhizal association. Mycorrhizal seedlings exhibited coils that are specific of Paris-type mycorrhizae. Both species benefited from the mycorrhizal symbiosis in terms of phosphorus acquisition but the growth of E. falcata seedlings was unresponsive to this mycorrhizal improvement of phosphorus status, probably because of the combination of high seed mass and P reserves, with low growth rate. • The two species belong to two different functional groups regarding phosphorus acquisition, D. guianensis being an obligate mycotrophic species.

Phytochemical analysis of mature tree root exudates in situ and their role in shaping soil microbial communities in relation to tree N-acquisition strategy.

Eperua falcata (Aublet), a late-successional species in tropical rainforest and one of the most abundant tree in French Guiana, has developed an original strategy concerning N-acquisition by largely preferring nitrate, rather than ammonium (H. Schimann, S. Ponton, S. Hättenschwiler, B. Ferry, R. Lensi, A.M. Domenach, J.C. Roggy, Differing nitrogen use strategies of two tropical rainforest tree species in French Guiana: evidence from (15)N natural abundance and microbial activities, Soil Biol. Biochem. 40 (2008) 487-494). Given the preference of this species for nitrate, we hypothesized that root exudates would promote nitrate availability by (a) enhancing nitrate production by stimulating ammonium oxidation or (b) minimizing nitrate losses by inhibiting denitrification. Root exudates were collected in situ in monospecific planted plots. The phytochemical analysis of these exudates and of several of their corresponding root extracts was achieved using UHPLC/DAD/ESI-QTOF and allowed the identification of diverse secondary metabolites belonging to the flavonoid family. Our results show that (i) the distinct exudation patterns observed are related to distinct root morphologies, and this was associated with a shift in the root flavonoid content, (ii) a root extract representative of the diverse compounds detected in roots showed a significant and selective metabolic inhibition of isolated denitrifiers in vitro, and (iii) in soil plots the abundance of nirK-type denitrifiers was negatively affected in rhizosphere soil compared to bulk. Altogether this led us to formulate hypothesis concerning the ecological role of the identified compounds in relation to N-acquisition strategy of this species.

Avaliação da gramatura de cola na propriedade de flexão estática em painéis compensados de Copaifera duckei Dwayer e Eperua oleifera Ducke / Evaluation of the glue amount in the static bending of the species Copaifera duckei Dwayer e Eperua oleifera Ducke

A presente pesquisa teve como objetivo analisar as seguintes gramaturas de cola: 270; 330; 364 e 390 g.m-² a partir da produção de compensados fenólicos utilizando duas espécies florestais; Copaifera duckei e Eperua oleifera e avaliar a flexão estática dos painéis. A madeira foi proveniente da área de manejo florestal sustentado da Indústria de Madeira Compensada localizada em Manicoré, município do Amazonas. As lâminas foram produzidas na Gethal Amazonas S.A - Indústria de Madeira Compensada em Itacoatiara - AM com espessura de 2,2 mm. Foram produzidas a nível industrial 40 painéis, 20 por espécie no total de 8 tratamentos. O experimento foi completamente casualizado com arranjo fatorial. Foi utilizado a norma Européia EN 310: 1993. Os valores de densidade básica da espécie Copaifera duckei foi de 0,60 (g.cm-²) e 0,62 (g.cm-²) para Eperua oleifera. No ensaio de flexão estática, sentido paralelo à grã, somente a espécie Copaifera duckei apresentou diferença significativa a 5 por cento pelo Teste de Dunnette para as propriedades de MOE e MOR. No sentido perpendicular a grã, as espécies Copaifera duckei e Eperua oleifera tanto o MOE quanto o MOR apresentaram diferenças significativas a 5 por cento de probabilidade.

The objective of the present research was to analyze 270; 330; 364 and 390 g.m-² amounts of glue in the production of fenolic plywood, using two forest species; Copaifera duckei and Eperua oleifera, and evaluate the static bending of the panels. The wood came from an area of sustained forest pertaining to the Plywood Industry located in Manicoré, county of Amazonas. The panels were produced with thicknesses of 2.2mm at the Gethal Amazonas S.A in Itacoatiara - AM. Forty panels, 20 per species, were produced an industrial level, using a total of 8 treatments. The experiment was completely randomized with factorial arrangement. The European standard EN 310: 1993 was used. The basic density values were 0.60 (g.cm-²) for Copaifera duckei, and 0.62 (g.cm-²) for Eperua oleifera. In static bending, parallel to the grain, only Copaifera duckei presented a significant difference at 5 percent in the Dunnette Test for the properties of MOE and MOR. In the perpendicular sense to the grain, Copaifera duckei and Eperua oleifera presented significant differences, for MOE as much as MOR, at 5 percent of probability.