Rahali, H., Ghanem, N., Griffe, L., Rahali, R., & Stien, D. (2004). A general approach to the quantification of resin-bound functional groups by NMR. New J. Chem., 28(11), 1344–1346.
Abstract: There has been a continuing need for sensitive, accurate and rapid methods to monitor functional loading of insoluble supports for solid phase synthesis. The present articles reports our findings regarding functional group loading quantification using H-1 NMR. Results obtained for supported amino, hydroxyl and NH-Fmoc groups are in agreement with those calculated using well-established methods and demonstrate that the strategy of looking, either at the excess reagent left in solution (NH2 and OH), or at the protecting group derivatives released from the polymer (Fmoc), is a viable approach to resin loading quanti. cation.
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Herault, B., & Thoen, D. (2009). How habitat area, local and regional factors shape plant assemblages in isolated closed depressions. Acta Oecol.-Int. J. Ecol., 35(3), 385–392.
Abstract: Classifying species by shared life-history traits is important if common ecological response groups are to be identified among different species. We investigated how habitat area, local and regional factors shape plant communities in small isolated closed depressions, and how the species richness is related to the interplay between environmental factors and specific life-history trait combinations. In Central-Western Europe, 169 closed depressions were completely Surveyed for plant presence in two highly contrasted landscapes (forested and open landscapes). All species were clustered into 9 Emergent Groups based oil 10 life-history traits related to plant dispersal, establishment and persistence. Habitat areas were related to species presence using logistic regressions. Most Emergent Groups were more area-dependent in open than in forested landscapes, owing to heterogeneous light levels in forest weakening the species-area relationship. In open landscapes, Floating Hydrophytes were severely underrepresented in very small depressions, owing to the absence of waterfowl poulation. Local environmental and regional factors were related to species richness using Generalized Linear Models. In open landscapes, local environmental factors such as water conductivity or soil productivity are respectively the main predictors. In forested landscapes, the abundance of most Emergent Groups Was better predicted by regional factors, i.e., habitat connectivity and distance to the forest edge. Forested landscapes strongly impeded the closed depressions' colonization by the less mobile Emergent Groups Such as Large-seeded Perennials. (C) 2009 Elsevier Masson SAS. All rights reserved.
Keywords: Closed depressions; Colonization; Connectivity; Fragmented habitats; Emergent Groups; Open and forested landscape; Life-history traits
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Donald, J., Maxfield, P., Leroy, C., & Ellwood, M. D. F. (2020). Epiphytic suspended soils from Borneo and Amazonia differ in their microbial community composition. Acta Oecol., 106.
Abstract: Microbial organisms support the high species diversity associated with tropical forests, and likely drive functional processes, but microorganisms found in rainforest canopies are not well understood. We quantified the microbial diversity of suspended soils from two classical epiphytic model systems (bromeliads & bird's nest ferns) across two localities: the Nouragues Reserve in French Guiana and Danum Valley in Malaysian Borneo. Non-epiphytic suspended soils were also collected as controls at the Nouragues Reserve. Effects of epiphyte type and sample location on microbial community composition were determined using Phospholipid Fatty Acid (PLFA) analysis. Total microbial biomass remained constant across the suspended soil types, but PLFA peaks denoting the relative abundance of different microbes varied between bromeliads, bird's nest ferns and non-epiphytic control soils. Suspended soils associated with bird's nest ferns from Borneo contained a microbial community significantly different in composition from those of congeneric bird's nest ferns from Amazonia, due to shifts in the relative abundance of fungi and bacteria. Our findings reveal that epiphytes create convergent niches for microorganisms in tropical canopies, while highlighting the sensitive nature of suspended soil microbial communities. © 2020 Elsevier Masson SAS
Keywords: Asplenium; Bacteria; Borneo; Bromeliaceae; Canopy; French Guiana; Fungi; Plfa; Rainforest; bacterium; community composition; epiphyte; fungus; microbial community; niche; relative abundance; soil microorganism; species diversity; tropical forest; Amazonia; Borneo; Danum Valley; East Malaysia; French Guiana; Malaysia; Nouragues; Sabah; Asplenium; Asplenium nidus; Aves; Bacteria (microorganisms); Bromeliaceae; Fungi
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Sierra, J., Daudin, D., Domenach, A. M., Nygren, P., & Desfontaines, L. (2007). Nitrogen transfer from a legume tree to the associated grass estimated by the isotopic signature of tree root exudates: A comparison of the N-15 leaf feeding and natural N-15 abundance methods. Eur. J. Agron., 27(2-4), 178–186.
Abstract: Nitrogen (N) transfer from legume trees to associated crops is a key factor for the N economy of low-input agroforestry systems. In this work, we presented a new approach to estimate N transfer based on the N-15 content of root exudates and N released by root turnover of the donor plant (Gliricidia sepium) and the temporal change of the N-15 content of the receiver plant (Dichanthium aristatum). The study was carried out in greenhouse using two isotopic methods: N-15 leaf feeding (LF) and the natural N-15 abundance (NA). Measurements of exudate N-15 were made at several dates before and after tree pruning. A time-dependent box model was devised to quantify N transfer in time and to make comparisons between the isotopic methods. In NA, although tree roots and exudates presented a similar N-15 signature before tree pruning, exudates were strongly depleted in N-15 after pruning. In LF, exudates were always depleted in N-15 in relation to tree roots. Hence, the current assumption used in N transfer studies concerning the equal N-15/N-14 distribution in tissues of the donor plant and in its excreted N was not confirmed in our study. Before pruning, N transfer functioned as a two-N-source system (soil N and exudates N) and both isotopic methods provided similar estimates: 11-12% for LF and 10-15% for NA. Calculations per-formed with the model indicated that N transfer occurred with small or nil fractionation of N-15 in exudates. After pruning, there was a third N source associated with N released from tree root turnover. During this period, the isotopic signature of the receiver plant showed a transient state due to the progressive decrease of N-15 content of that N source. The amount of N derived from the tree represented 65% of the total N content of the. grass at the end of the experiments. (c) 2007 Elsevier B.V. All rights reserved.
Keywords: agroforestry; box model; gliricidia sepium; N-15 fractionation; root turnover; tree pruning
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Maron, P. A., Schimann, H., Ranjard, L., Brothier, E., Domenach, A. M., Lensi, R., et al. (2006). Evaluation of quantitative and qualitative recovery of bacterial communities from different soil types by density gradient centrifugation. Eur. J. Soil Biol., 42(2), 65–73.
Abstract: Extracting and purifying a representative fraction of bacteria from soil is necessary for the application of many techniques of microbial ecology. Here the influence of different soil types on the quantitative and qualitative recovery of bacteria by soil grinding and Nycodenz density gradient centrifugation was investigated. Three soils presenting contrasted physicochemical characteristics were used for this study. For each soil, the total (AODC: acridine orange direct count) and culturable (cfa: colony-forming units) bacterial densities were measured in three distinct fractions: (i) the primary soil, (ii) the soil pellet (soil remaining after centrifugation), and (iii) the extracted cells. The automated-ribosomal intergenic spacer analysis (A-RISA) was used to characterize the community structure directly from the DNA extracted from each fraction. The physicochemical characteristics of soils were found to influence both the efficiency of bacterial cell recovery and the representativeness of the extracted cells in term of community structures between the different fractions. Surprisingly, the most representative extracted cells were obtained from the soil exhibiting the lowest efficiency of cell recovery. Our results demonstrated that quantitative and qualitative cell recovery using Nycodenz density gradient centrifugation are not necessarily related and could be differentially biased according to soil type. (c) 2006 Elsevier SAS. All rights reserved.
Keywords: bacterial community; soil; density gradient; DNA fingerprint
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Male, P. J. G., Loiseau, A., Estoup, A., Quilichini, A., & Orivel, J. (2010). Characterization of polymorphic microsatellite loci in the neotropical plant-ant Allomerus decemarticulatus (Formicidae: Myrmicinae) and multiplexing with other microsatellites from the ant subfamily Myrmicinae. Eur. J. Entomol., 107(4), 673–675.
Abstract: Five polymorphic microsatellite loci of the arboreal ant Allomerus decemarticulatus (Myrmicinae) were isolated and characterized. The amplification and polymorphism of seven additional microsatellite loci, previously developed for the ant species A. octoarticulatus and Wasmannia auropunctata, were also tested and the amplification conditions necessary for genotyping the complete set of 12 multiplexed markers in A. decemarticulatus determined. The number of alleles per locus ranged from three to 15 and observed heterozygosity varied front 0.09 to 0.95. Cross-species amplification of these loci was also successfully achieved in additional species of the same ant subfamily, Myrmicinae. This set of microsatellite markers will be used in studies on the mating system and population genetic structure of Myrmicinae in general and A. decemarticulatus in particular.
Keywords: Hymenoptera; Formicidae; Myrmicinae; Allomerus; ant-plant mutualism; microsatellites; plant-ant
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Pickett, K. M., Carpenter, J. M., & Dejean, A. (2009). “Basal” but not primitive: the nest of Apoica arborea de Saussure, 1854 (Insecta, Hymenoptera, Vespidae, Polistinae). Zoosystema, 31(4), 945–948.
Abstract: The first nest of Apoica arborea ever collected is reported. Characteristics of the unusual nest design are discussed relative to other members of the genus Apoica and other epiponine genera. The characteristics of its nest architecture are a mosaic of primitive and derived features for the Polistinae, and thus the nest design is not properly interpreted as the primitive condition from which other swarm-founding wasp nest designs are derived. The frequent conflation of “basal” and primitive is discussed.
Keywords: Insecta; Hymenoptera; Vespidae; Polistinae; Apoica; social wasps; nest architecture; mosaic evolution
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Scotti, I. (2010). Adaptive potential in forest tree populations: what is it, and how can we measure it? Ann. For. Sci., 67(8), 801.
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Bremaud, I., Minato, K., Langbour, P., & Thibaut, B. (2010). Physico-chemical indicators of inter-specific variability in vibration damping of wood. Ann. For. Sci., 67(7), 707.
Abstract: The vibration damping coefficient (tan delta) of wood is an important property for acoustical uses, including musical instruments. Current difficulties in the availability of some of the preferred species call for diversification, but this comes up against the lack of systematic damping coefficient data. Keeping in mind the possible factors affecting tans, could we predict its variations between species, by using indicators that are either easily measured and/or readily available for many species? Vibrational properties, equilibrium moisture content and colorimetric parameters were assessed on 94 wood types belonging to 76 species. Experimental results were then related to data on chemical contents and physical properties from the CIRAD database. The “standard” relationship between tan delta and specific modulus of elasticity (E'/rho) explained only half of the variations. Deviations from this trend were correlated to extractives content, yet effects were not directly quantitative. Damping deviations were also correlated to colour and moisture-related properties, especially so with fibre saturation point. By taking into account a combination of moisture-related properties, colour – or extractives content, and the “standard” relationship between tans and E'/rho, we could propose simple predictive models which explain up to 89% of observed variations in tan delta between 48 species.
Keywords: damping coefficient; diversity of woods; extractives; physical properties; vibrational properties
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Coste, S., Baraloto, C., Leroy, C., Marcon, E., Renaud, A., Richardson, A. D., et al. (2010). Assessing foliar chlorophyll contents with the SPAD-502 chlorophyll meter: a calibration test with thirteen tree species of tropical rainforest in French Guiana. Ann. For. Sci., 67(6), 607.
Abstract: Chlorophyll meters such as the SPAD-502 offer a simple, inexpensive and rapid method to estimate foliar chlorophyll content. However, values provided by SPAD-502 are unitless and require empirical calibrations between SPAD units and extracted chlorophyll values. Leaves of 13 tree species from the tropical rain forest in French Guiana were sampled to select the most appropriate calibration model among the often-used linear, polynomial and exponential models, in addition to a novel homographic model that has a natural asymptote. The homographic model best accurately predicted total chlorophyll content (mu g cm(-2)) from SPAD units (R-2 = 0.89). Interspecific differences in the homographic model parameters explain less than 7% of the variation in chlorophyll content in our data set. The utility of the general homographic model for a variety of research and management applications clearly outweighs the slight loss of model accuracy due to the abandon of the species' effect.
Keywords: chlorophyll estimate; model calibration; homographic functions; neotropical trees
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