Éditeur(s) : HAL CCSD Wiley
Résumé : A standardized rapid inventory method providing information on both tree species diversity and aboveground carbon stocks in tropical forests will be an important tool for evaluating efforts to conserve biodiversity and to estimate the carbon emissions that result from deforestation and degradation (REDD). Herein, we contrast five common plot methods differing in shape, size, and effort requirements to estimate tree diversity and aboveground tree biomass (AGB). We simulated the methods across six Neotropical forest sites that represent a broad gradient in forest structure, tree species richness, and floristic composition, and we assessed the relative performance of methods by evaluating the bias and precision of their estimates of AGB and tree diversity. For a given sample of forest area, a several small' (<1ha) sampling strategy led to a smaller coefficient of variation (CV) in the estimate of AGB than a few large' one. The effort (person-days) required to achieve an accurate AGB estimate (<10% CV), however, was greater for the smallest plots (0.1ha) than for a compromise approach using 0.5ha modified Gentry plots, which proved to be the most efficient method to estimate AGB across all forest types. Gentry plots were also the most efficient at providing accurate estimates of tree diversity (<10% CV of Hill number). We recommend the use of the 0.5ha modified Gentry plot method in future rapid inventories, and we discuss a set of criteria that should inform any choice of inventory method.
ISSN: 0006-3606

hal-01032408
https://hal.archives-ouvertes.fr/hal-01032408
DOI : 10.1111/btp.12006

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : Architectural analyses of temperate tree species using a chronological approach suggest that the expression of epicormic branches is closely related to low growth rates in the axes that make up the branching system. Therefore, sole consideration of epicormic criteria may be sufficient to identify trees with low secondary growth levels or with both low primary and secondary growth levels. In a tropical tree such as Dicorynia guianensis (basralocus), where chronological studies are difficult, this relationship could be very useful as an easily accessible indicator of growth potentials. A simple method of architectural tree description was used to characterize the global structure of more than 1650 basralocus trees and to evaluate their growth level. Measurements of simple growth characters [height, basal diameter, internode length of submittal part (top of the main axis of the tree)] and the observation of four structural binary descriptors on the main stem (presence of sequential branches and young epicormic branches, state of the submittal part, global orientation), indicated that epicormic branch formation is clearly related to a decrease in length of the successive growth units of the main stem. Analysis of height vs. diameter ratios among different tree subgroups, with and without epicormic branching, suggested that trees with epicormic branches generally have a low level of secondary growth compared with primary growth.
ISSN: 0305-7364

hal-01032037
https://hal.archives-ouvertes.fr/hal-01032037
DOI : 10.1093/aob/mcg119

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
We explored the relationship between soil processes, estimated through soil respiration (Rsoil), and the spatial variation in forest structure, assessed through the distribution of tree size, in order to understand the determinism of spatial variations in Rsoil in a tropical forest. The influence of tree size was examined using an index (Ic) calculated for each tree as a function of (1) the trunk cross section area and (2) the distance from the measurement point. We investigated the relationships between Ic and litterfall,root mass and Rsoil, respectively. Strong significant relationships were found between Ic and both litterfall and root mass. Rsoil showed a large range of variations over the 1-ha experimental plot, from 1.5 to 12.6 gC m−2 d−1. The best relationship between Ic and Rsoil only explained 17% of the spatial variation in Rsoil. These results support the assumption that local spatial patterns in litter production and root mass depend on tree distribution in tropical forests. Our study also emphasizes the modest contribution of tree size distribution-which is mainly influenced by the presence of the biggest trees (among the large range size of the inventoried trees greater than 10 cm diameter at 1.30 m above ground level or at 0.5 m above the buttresses)-in explaining spatial variations in Rsoil.
ISSN: 0032-079X

hal-00797064
https://hal.archives-ouvertes.fr/hal-00797064

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Variation of dead wood decay rates among tropical trees remains one source of uncertainty in global models of the carbon cycle. Taking advantage of a broad forest plot network surveyed for tree mortality over a 23-year period, we measured the remaining fraction of boles from 367 dead trees from 26 neotropical species widely varying in wood density (0.23–1.24 g cm-3) and tree circumference at death time (31.5–272.0 cm). We modeled decay rates within a Bayesian framework assuming a first order differential equation to model the decomposition process and tested for the effects of forest management (selective logging vs. unexploited), of mode of death (standing vs. downed) and of topographical levels (bottomlands vs. hillsides vs. hilltops) on wood decay rates. The general decay model predicts the observed remaining fraction of dead wood (R2 = 60%) with only two biological predictors: tree circumference at death time and wood specific density. Neither selective logging nor local topography had a differential effect on wood decay rates. Including the mode of death into the model revealed thatstanding dead trees decomposed faster than downed dead trees, but the gain of model accuracy remains rather marginal. Overall, these results suggest that the release of carbon from tropical dead trees to the atmosphere can be simply estimated using tree circumference at death time and wood density.
ISSN: 0029-8549

hal-01094187
https://hal-agroparistech.archives-ouvertes.fr/hal-01094187
DOI : 10.1007/s00442-010-1602-8

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent.
ISSN: 1932-6203

hal-01268529
https://hal.archives-ouvertes.fr/hal-01268529
https://hal.archives-ouvertes.fr/hal-01268529/document
https://hal.archives-ouvertes.fr/hal-01268529/file/journal.pone.0092337.PDF
DOI : 10.1371/journal.pone.0092337

Résumé : Arbusto o arbolito de hasta 5 m, con látex amarillo lechoso o rojizo. Hojas redondeado-aovadas, 3-5 lobadas, cordadas en la base, agudas o acuminadas en el ápice. Cimas pequeñas, densas, largo-pedunculadas; pétalos blanquecinos oblongo-ovados, densamente pilosos. Cápsula elipsoide, de 2.5 a 4 cm; semillas de 2 cm, negruzcas.
Arbuste ou petit arbre pouvant atteindre 5 m, avec un latex jaune laiteux ou rougeâtre. Feuilles arrondies-ovées, à 3-5 lobes, cordées à la base, à l&rsquo;extrémité aiguë ou acuminée. Cymes petites, denses, à longs pédoncules; pétales blanchâtres oblong-ovés, à pilosité dense. Capsule ellipsoïdale, de 2,5 à 4 cm. Graines de 2 cm, noirâtres.
Shrub or small tree, up to 5 m high, with sticky, milky or reddish latex.  Leaves broadly ovate, margins entire or shallowly 3-5-lobed, cordate at base, acute or acuminate at apex, 15cm x 13cm; cymes with or without peduncles; flowers unisexual, born at different times on the same inflorescence, petals green 6-7 mm long; capsule ellipsoid, 2.5-4 cm long; seeds blackish ca.2 cm long.
Originaria de América tropical, se ha naturalizado en otras regiones tropicales.
Originaire d’;Amérique tropicale, naturalisée dans d’;autres régions tropicales.
Native to tropical America. Naturalized in other tropical regions.

http://www.tramil.net/fototeca/plant200

Résumé : Arbol de hasta 18 m de alto. Hojas pecioladas, subcoriáceas, oblongo elípticas a lanceoladas, agudamente acuminadas, pinnado nervadas de hasta 13 cm de longitud. Inflorescencias estaminadas de 3 a 20 flores; las pistiladas usualmente de una sola flor; flores pequeñas, amarillo cremosas. Fruto piriforme o subgloboso (nuez) de hasta 5 cm, colgante, rojizo o amarillento, con dos valvas; semilla con arilo escarlata.
Arbre pouvant atteindre 18 m de haut. Feuilles pétiolées, presque coriaces, oblongo-elliptiques à lancéolées, terminées en pointe très fine, pennatinnervées pouvant atteindre 13 cm de long. Inflorescences staminées de 3 à 20 fleurs; celles qui sont pourvues d&rsquo;un pistil ont habituellement une seule fleur; fleurs petites, jaunes-crèmes. Fruit piriforme ou presque arrondi pouvant atteindre 5 cm, tombant, rougeâtre ou jaunâtre, bivalve; graine avec arille écarlate.
Tree dioecious 6-18 m high with a dense crown and aromatic wood.  Leaves simple, alternate, oblong-elliptic, acutely acuminate, pinnately veined, dark green shiny above, paler beneath, 5-15 cm x 2-7 cm; male inflorescences usually 1-10 flowered cyme, fragrant, pale yellow, female inflorescences a 1-3 flowered cyme, but usually 1-flowered, pale yellow; fruit a fleshy, smooth, yellow, sub-globose, drupe, 3-6 cm long with a circumferential, longitudinal ridge; seed brown, ovoid 1.5-4.5cm long covered with a lacinate, red aril.
Nativa de Asia tropical, cultivada en los trópicos del resto del mundo.
Originaire d’;Asie tropicale, cultivée dans les tropiques du reste du monde.
Native to tropical Asia, cultivated in tropical regions around the world.

http://www.tramil.net/fototeca/plant239

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé :  
In this paper, we report a study of the mating system and gene flow of Symphonia globulifera, a hermaphroditic, mainly bird-pollinated tree species with a large geographic distribution in the tropical Americas and Africa.Using three microsatellites, we analysed 534 seeds of 28 open pollinated families and 164 adults at the experimental site 'Paracou' in French Guiana. We observed, compared to other tropical tree species, relatively high values for the effective number of alleles. Significant spatial genetic structure was detected, with trees at distances up to 150 m more genetically similar than expected at random. We estimated parameters of the mating system and gene flow by using the mixed mating model and the TwoGener approach. The estimated multilocus outcrossing rate, tm, was 0.920. A significant level of biparental inbreeding and a high proportion of full-sibs were estimated for the 28 seed arrays. We estimated mean pollen dispersal distances between 27 and 53 m according to the dispersal models used. Although the adult population density of S. globulifera in Paracou was relatively high, the joint estimation of pollen dispersal and density of reproductive trees gave effective density estimates of 1.6 and 1.3trees/ha. The parameters of the mating system and gene flow are discussed in the context of spatial genetic and demographic structures, flowering phenology and pollinator composition and behaviour.
ISSN: 0018-067X

hal-01032178
https://hal.archives-ouvertes.fr/hal-01032178
DOI : 10.1038/sj.hdy.6800560

Résumé : Árbol de tamaño mediano de hasta 6 m, copa redonda; ramas con espinas delgadas, flexibles, ocasionalmente ausentes. Hojas ampliamente elípticas de 6 a 11 cm de largo con el ápice obtuso o agudo, base cuneada a redondeada. Flores solitarias o en racimos cortos, blancas, aromáticas. Fruto globoso u oval, con 10 a 13 segmentos, pulpa amarillenta, dulce.
Arbre de taille moyenne pouvant atteindre 6 m, cime arrondie; branches avec épines fines, souples, parfois absentes. Feuilles très elliptiques de 6 à 11 cm de longueur avec une pointe obtuse ou aiguë, base rhomboïdale ou arrondie. Fleurs solitaires ou en grappes courtes, blanches, aromatiques. Fruit rond ou ovale, avec 10 à 13 segments, pulpe jaunâtre, sucrée.
Tree 6 -12 m tall with spines. Leaves ovate or oval-elliptic 5-15 cm x 2-8 cm, glabrous dark green above, margins serrate, petiole narrowly winged and articulate; flowers axillary, born single or in small racemes, 2-3cm in diameter, white, aromatic; fruit subglobose or oval, 4-12 cm in diameter, peel thick, ripening orange colour but often remaining green in the tropics, pulp sweet and juicy, seeds nil to many obovoid.
Nativa de Asia, ampliamente cultivada en regiones tropicales y subtropicales.
Originaire d’;Asie, cultivée dans de vastes régions tropicales et subtropicales.
Native to Asia, widely cultivated in tropical and subtropical regions.

http://www.tramil.net/fototeca/plant136

Résumé : Arbusto o arbolito glabro, de hasta 10 m de altura. Hojas alternas, lineares a linear-lanceoladas, estrechamente acuminadas, brillantes en el haz. Inflorescencia terminal o lateral con pocas flores; lóbulos de la corola obovados a ovado-lanceolados; corola hipocraterimorfa, de color naranja o rosado-amarillenta. Drupas rojas al madurar, con dos semillas.
Arbuste ou petit arbre glabre, pouvant atteindre 10 m de haut. Feuilles alternes, linéaires à linéaires-lancéolées, effilées à la pointe, brillantes sur le dessus. Inflorescence terminale ou latérale avec peu de fleurs; lobes de la corolle obovales à ovés-lancéolés; corolle hypocratérimorphe, de couleur orange ou rose-jaunâtre. Drupes rouges lorsqu&rsquo;elles sont arrivées à maturité, avec deux graines.
Shrub or small tree 3-7 m high, glabrous with milky sap. Leaves spirally arranged, linear, 10-15 x 0.6-1cm, shiny on the upper side; Inflorescence terminal cymes, few-flowered; corolla tubular-campanulate, flower 7-8.5 cm long, bright yellow or pinkish-orange; fruit sickle-shape, 2 x 3 cm, yellow when ripe with a single triangular seed 2 x3 cm.
Nativa de América tropical, cultivada ampliamente en los trópicos de ambos hemisferios.
Originaire d’;Amérique tropicale, abondamment cultivée sous les tropiques des deux hémisphères.
Native to tropical America, widely cultivated in the tropica

http://www.tramil.net/fototeca/plant349

Résumé : Arbusto o arbolito de hasta 12 m, ramas armadas con espinas rectas. Hojas pecioladas, compuestas, glabras; 1 a 3 pares de pinas; con folíolos de 12 a 20 pares por pinna, sésiles, linear-oblongos. Flores verde-amarillentas, sésiles, en espigas cilíndricas, densas, de 5 a 10 cm de longitud, pedunculadas. Vaina comprimida, falcada, coriácea indehiscente; semillas aplanadas, ovales de color café.
Arbuste ou petit arbre pouvant atteindre 12 m, branches armées d&rsquo;épines droites. Feuilles pétiolées glabres, bipennées ou tripennées, dont chaque élément porte 12 à 20 paires de folioles, sessiles, linéaires-oblongues.Fleurs vert-jaunâtres, sessiles, en épis cylindriques, denses, de 5 à 10 cm de longueur, pédonculées. Gousse comprimée, en forme de lame de faucille, coriace indéhiscente; graines plates, ovales, couleur café.
Shrub or small tree, up to 12 m high with spreading branches armed with straight spines 0.6-2.5 cm.  Leaves, petiolate 1-4 cm, bipinnate with glands between pairs of pinnae, pinnae 1 pair rarely 2, leaflets 12-20 pairs linear-oblong, 7-16 x 1.5-3.2 mm, apex obtuse or short abrupt point; inflorescence axillary in spikelike racemes, 5-10 cm long; flowers densely packed with pale yellow corolla 2.5 mm long; pod compressed, 7-20 cm x 1-1.6 cm, slightly curved, pale yellow; seeds brown 6 mm embedded in white sweet pulp.
Nativa de América tropical.
Originaire d’;Amérique tropicale.
Native to tropical America.

http://www.tramil.net/fototeca/plant259

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Heartwood/sapwood profile and the tradeoff between trunk and crown increment in a natural forest: the case study of a tropical tree (Dicorynia guianensis Amsh., Fabaceae) Key message Sapwood area and the radial growth rate of the trunk follow the same pattern at breast height, with an initial increase and subsequent constant value, resulting from the increasing growth allocation toward the crown rather than tree decline. Heartwood area and heartwood volume in the trunk increase more rapidly after this shift occurs. Abstract Sapwood (SW) and heartwood (HW) are two functionally distinct classifications of wood in perennial stems for which quantities can vary greatly in tropical trees. Numerous positive correlations have been found between the radial growth rate (RGR) and SW quantity; however, variations in the SW/HW quantities have not been studied in light of the ontogenetic variation of RGR. Wood core sampling, intensive measurements of tree structure (number of branches, stem volumes), and radial growth monitoring were performed on an abundant and highly exploited tree species in French Guiana (Dicorynia guianensis) to investigate the relationship between RGR, SW/HW quantity, tree structure, and their variations on the course of a tree's ontogeny. SW area and RGR followed the same pattern of variation throughout tree development, both increasing first and reaching a steady state after 50 cm DBH (diameter at breast height). After this value, we observed a strong increase in both the HW area and HW volume increment, concomitant with a more rapid increase in crown volume. The stabilization of RGR for trees with DBH >50 cm was related not to a tree's decline but rather to an increasing wood allocation to the crown, confirming that RGR at breast height is a poor indicator of whole-tree growth for bigger individuals. We also confirmed that HW formation is an ontogenetic process managing SW quantity that is continuously and increasingly produced within the crown as the tree grows. This study highlights the effect of growth-mediated ontogenetic changes on the localization of water and carbohydrate storage within a tree, resulting from SW and HW dynamics throughout tree ontogeny.
ISSN: 0931-1890

hal-01654003
https://hal.archives-ouvertes.fr/hal-01654003
https://hal.archives-ouvertes.fr/hal-01654003/document
https://hal.archives-ouvertes.fr/hal-01654003/file/Lehnebach%20et%20al.%E2%80%94Trees%202016-%20Own%20version.pdf
DOI : 10.1007/s00468-016-1473-7

Résumé : Arbusto o arbolito de hasta 9 m, muy ramificado. Hojas alternas, aovadas, de 8 a 20 cm, acuminadas, cordadas en la base, enteras. Inflorescencia en panículas terminales; flores de 4 a 5.3 cm de diámetro; pétalos rosados o blancos, obovados a anchamente ovales. Cápsula (fruto) ovoidea a globoso-ovoidea, de 3 a 4 cm, usualmente con espinas blandas. Semillas con un arilo rojo.
Arbuste ou petit arbre pouvant atteindre 9 m, très ramifié. Feuilles alternes, ovalées, de 8 à 20 cm, acuminées, cordées à la base, entières. Inflorescence en panicules terminaux; fleurs de 4 à 5,3 cm de diamètre; pétales rosés ou blancs, courbes à largement ovales. Capsule ovalée à globuleuse-ovalée, de 3 à 4 cm, avec habituellement des épines molles. Graines avec un arille rouge.
Shrub or small tree, up to 9 m in height, with many branches.  Leaves alternate, ovate, 8 to 20 cm in length, cordate at the base, entire.  Inflorescence in terminal panicles; flowers 4 to 5.3 cm wide; pink or white petals, obovate to broadly oval.  Capsule (fruit), ovoid to globosely-ovoid, 3 to 4 cm in length, usually with soft thorns.  Seed with red aril.
Originaria del trópico americano, cultivada en las regiones tropicales.
Originaire du tropique américain, cultivée dans les régions tropicales.
Native from American tropic and cultivated in tropical regions.

http://www.tramil.net/fototeca/plant101

Résumé : Arbol de 4-5 (raras veces 8) metros de altura, tronco de hasta 20 cm de diámetro y ramas extendidas. Hojas corto-pecioladas, espatuladas, fasciculadas, de 5 a 20 cm. Flores solitarias, amarillentas con venas de color púrpura, de 5 a 6 cm; lóbulos lacerados. Fruto globoso o elipsoideo, liso, lustroso, de 10 a 30 cm de diámetro, de cáscara dura.
Petit arbre de 8 m ou moins, tronc pouvant avoir jusqu&rsquo;à 20 cm de diamètre et branches allongées. Feuilles à court pétiole, spatulées, fasciculées, de 5 à 20 cm. Fleurs solitaires, jaunâtres avec des veines pourpres, de 5 à 6 cm; lobes très découpés. Fruit arrondi ou ellipsoïdal, lisse, brillant, de 10 à 30 cm de diamètre, à l&rsquo;écorce dure.
Small tree, up to 8 m tall with shorttrunk up to 20 cm in diameter with long spreading branches; leaves short-petiolate, spatulate, fasciculate, 5-20 cm long; flowers bell-shaped, born on the trunk in clusters, 5-6 cm long, greenish- white to greenish-yellowish with purple markings, foul smelling; fruit globose to ellipsoid, smooth, shiny, 10-30 cm in diameter, with hard shell.
Nativa de América tropical continental, cultivada y naturalizada en los trópicos.
Originaire de l’;Amérique tropicale continentale, cultivée et acclimatée sous les tropiques.
Native to tropical continental America, cultivated and naturalized

http://www.tramil.net/fototeca/plant150

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
1. Estimating forest above-ground biomass (AGB), or carbon (AGC), in tropical forests has become a majorconcern for scientists and stakeholders. However, AGB assessment procedures are not fully standardized andeven more importantly the uncertainty associated with AGB estimates is seldom assessed.2. Here, we present an R package designed to compute both AGB/AGC estimate and its associated uncertaintyfrom forest plot datasets, using a Bayesian inference procedure. The package builds upon previous work onpantropical and regional biomass allometric equations and published datasets by default but it can alsointegrate unpublished or complementary datasets in many steps.3. BIOMASS performs a number of standard tasks on input forest tree inventories: i) tree speciesidentification, if available, is automatically corrected; ii) wood density is estimated from tree species identity;iii) if height data are available, a local height-diameter allometry may be built; else height is inferred frompantropical or regional models; iv) finally, AGB/AGC are estimated by propagating the errors associated withall the calculation steps up to the final estimate. R code is given in the paper and in the appendix forillustration purpose.4. The BIOMASS package should contribute to improved standards for AGB calculation for tropical foreststands, and will encourage users to report the uncertainties associated with stand-level AGB/AGC estimatesin future studies.
ISSN: 2041-210X

hal-01558180
https://hal.archives-ouvertes.fr/hal-01558180
DOI : 10.1111/2041-210X.12753

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Ethnopharmacological relevancePsidium acutangulum Mart. ex DC is a small tree used by the Wayana Amerindians from the Upper-Maroni in French Guiana for the treatment of malaria.Aim of the studyIn a previous study, we highlighted the in vitro antiplasmodial, antioxidant and anti-inflammatory potential of the traditional decoction of P. acutangulum aerial parts. Our goal was then to investigate on the origin of the biological activity of the traditional remedy, and eventually characterize active constituents.Materials and methodsLiquid-liquid extractions were performed on the decoction, and the antiplasmodial activity evaluated against chloroquine-resistant FcB1 ([3H]-hypoxanthine bioassay) and 7G8 (pLDH bioassay) P. falciparum strains, and on a chloroquine sensitive NF54 ([3H]-hypoxanthine bioassay) P. falciparum strain. The ethyl acetate fraction (D) was active and underwent bioguided fractionation. All the isolated compounds were tested on P. falciparum FcB1 strain. In vitro anti-inflammatory activity (IL-1β, IL-6, IL-8, TNFα) of the ethyl acetate fraction and of an anti-Plasmodium active compound, was concurrently assessed on LPS-stimulated human PBMC and NO secretion inhibition was measured on LPS stimulated RAW murine macrophages. Cytotoxicity of the fractions and pure compounds was measured on VERO cells, L6 mammalian cells, PBMCs, and RAW cells.ResultsFractionation of the ethyl acetate soluble fraction (IC50 ranging from 3.4 to <1 µg/mL depending on the parasite strain) led to the isolation of six pure compounds: catechin and five glycosylated quercetin derivatives. These compounds have never been isolated from this plant species. Two of these compounds (wayanin and guaijaverin) were found to be moderately active against P. falciparum FcB1 in vitro (IC50 5.5 and 6.9 µM respectively). We proposed the name wayanin during public meetings organized in June 2015 in the Upper-Maroni villages, in homage to the medicinal knowledge of the Wayana population. At 50 µg/mL, the ethyl acetate fraction (D) significantly inhibited IL-1β secretion (−46%) and NO production (−21%), as previously observed for the decoction. The effects of D and guiajaverin (4) on the secretion of other cytokines or NO production were not significant.ConclusionsThe confirmed antiplasmodial activity of the ethyl acetate soluble fraction of the decoction and of the isolated compounds support the previous results obtained on the P. acutangulum decoction. The antiplasmodial activity might be due to a mixture of moderately active non-toxic flavonoids. The anti-inflammatory activities were less marked for ethyl acetate fraction (D) than for the decoction.
ISSN: 0378-8741

hal-01313006
http://hal.upmc.fr/hal-01313006
http://hal.upmc.fr/hal-01313006/document
http://hal.upmc.fr/hal-01313006/file/Houel_Wayanin_and.pdf
DOI : 10.1016/j.jep.2016.04.053

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : The patterns of the distribution of fungal species and their potential interactions with trees remain understudied in Neotropical rainforests, which harbor more than 16,000 tree species, mostly dominated by endomycorrhizal trees. Our hypothesis was that tree species shape the non-mycorrhizal fungal assemblages in soil and litter and that the diversity of fungal communities in these two compartments is partly dependent on the coverage of trees in the Neotropical rainforest. In French Guiana, a long-term plantation and a natural forest were selected to test this hypothesis. Fungal ITS1 regions were sequenced from soil and litter samples from within the vicinity of tree species. A broad range of fungal taxa was found, with 42 orders and 14 classes.Significant spatial heterogeneity in the fungal communities was found without strong variation in the species richness and evenness among the tree plots. However, tree species shaped the fungal assemblages in the soil and litter, explaining up to 18 % of the variation among the communities in the natural forest.These results demonstrate that vegetation cover has an important effect on the structure of fungal assemblages inhabiting the soil and litter in Amazonian forests, illustrating the relative impact of deterministic processes on fungal community structures in these highly diverse ecosystems.
ISSN: 0095-3628

hal-01595373
https://hal.archives-ouvertes.fr/hal-01595373
DOI : 10.1007/s00248-016-0839-0
PRODINRA : 395655
PUBMED : 27645139

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Plant litter diversity effects on decomposition rates are frequently reported, but with a strong bias towards temperate ecosystems. Altered decomposition and nutrient recycling with changing litter diversity may be particularly important in tree species-rich tropical rainforests on nutrient-poor soils. Using 28 different mixtures of leaf litter from 16 Amazonian rainforest tree species, we tested the hypothesis that litter mixture effects on decomposition increase with increasing functional litter diversity. Litter mixtures and all single litter species were exposed in the field for 9 months using custom-made microcosms with soil fauna access. In order to test the hypothesis that the long-term presence of tree species contributing to the litter mixtures increases mixture effects on decomposition, microcosms were installed in a plantation at sites including the respective tree species composition and in a nearby natural forest where these tree species are absent. We found that mixture decomposition deviated from predictions based on single species, with predominantly synergistic effects. Functional litter diversity, defined as either richness, evenness, or divergence based on a wide range of chemical traits, did not explain the observed litter mixture effects. However, synergistic effects in litter mixtures increased with the long-term presence of tree species contributing to these mixtures as the home field advantage hypothesis assumes. Our data suggest that complementarity effects on mixed litter decomposition may emerge through long-term interactions between aboveground and belowground biota.
ISSN: 0029-8549

hal-01032393
https://hal.archives-ouvertes.fr/hal-01032393
DOI : 10.1007/s00442-011-1966-4

Éditeur(s) : HAL CCSD
Résumé : International audience
Over the past decade, much attention has been devoted to the development of forest biomass estimation methods at a stand scale, leading to the establishment of allometric models (Chave et al., 2014). These allometric equations use a unique wood specific gravity value (WSG) per species, but neglect the within tree variations of WSG found by others (Wiemann & Williamson, 1989).The main objectives of this study are (1) to illustrate the diversity of radial (from pith to bark) and longitudinal (from bottom to top) patterns of WSG variation within and between species, (2) to highlight different trends of WSG radial variations and the possible misinterpretations of these trends due to the effect of heartwood and (3) to link these variations and patterns to the successional status of the species (from pioneer to sciaphilic species).We sampled 33 small trees (10 Wood sciences underpinning tropical ecology and management. International closing symposium of the XYLAREDD project.
Tervuren, Belgium

hal-01188894
https://hal-sde.archives-ouvertes.fr/hal-01188894

Résumé : Arbolito con ramas irregulares, armado con espinas gruesas, rígidas y filosas. Hojas de 5 a 7.5 cm de largo, elíptico-ovales, crenadas; pecíolos alados. Flores blancas de 2 cm de largo. Frutos redondos de 3 a 6 cm, verdoso amarillentos, con abundante pulpa ácida. Semillas pequeñas blancas, ovales.
Arbuste aux branches irrégulières, armé de fortes épines, rigides et coupantes. Feuilles de 5 à 7,5 cm de long, elliptico-ovales, crénelées; pétioles en forme d&rsquo;aile. Fleurs blanches de 2 cm de long. Fruits ronds de 3 à 6 cm, vert jaune, avec une abondante pulpe acide. Pépins blancs, ovales.
Small tree with irregular branches up to 5 m tall, with thick, rigid, sharp thorns. Leaf elliptical, dark green, slightly leathery and aromatic, 4-8 cm x 2-5cm, petiole narrowly winged; inflorescence a raceme; flowers white, fragrant, 1.5 cm long; fruit sub-spherical, 5-6 cm long, yellow when ripe, with very acid pulp, seeds white, small, oval.
Nativa de Asia, cultivada en regiones tropicales y subtropicales.
Originaire d&rsquo;Asie, cultivée dans les régions tropicales et subtropicales.
Native to Asia, cultivated in tropical and subtropical regions.

http://www.tramil.net/fototeca/plant32