|
Scotti-Saintagne, C., Bertocchi, E., Barreneche, T., Kremer, A., & Plomion, C. (2005). Quantitative trait loci mapping for vegetative propagation in pedunculate oak. Ann. For. Sci., 62(4), 369–374.
Abstract: Vegetative propagation is one of the main methods used for the deployment of improved genetic forest tree species. The objective of this paper was to study the genetic architecture of vegetative propagation by detecting Quantitative Trait Loci (QTL) in pedunculate oak ( Quercus robur). The mapping population consisted on an F-1 family of 278 offspring. Assessment of rooting ability over three years permitted the detection of 10 QTLs explaining between 4.4 and 13.8% of phenotypic variance, of which the two strongest were stable across years. Ongoing genomics programs in trees and in Arabidopsis are starting to shed light on the nature of the underlying genes.
Keywords: vegetative propagation; QTL; Quercus robur
|
|
|
Almeras, T., Gril, J., & Yamamoto, H. (2005). Modelling anisotropic maturation strains in wood in relation to fibre boundary conditions, microstructure and maturation kinetics. Holzforschung, 59(3), 347–353.
Abstract: A generalisation of existing mechanical models is proposed to account for the relation between wood macroscopic properties and fibre microstructure and chemical composition. It is applied to understanding of the origin of anisotropic maturation strains measured at the outermost surface of the xylem. Various assumptions are considered for boundary conditions of the fibre during the progressive maturation process and are applied to experimental data from the literature. Assumptions that the fibre is fully restrained in displacement, or fully unrestrained or unrestrained in the transverse direction only are all incompatible with observations. Indeed, within the tree, the fibre is restrained in the longitudinal and tangential directions, but unrestrained in the radial direction towards the bark. Mixed boundary conditions must be introduced to correctly simulate both longitudinal and tangential maturation strains. In the context of an analytical axisymmetric model, this is estimated by considering a parameter of partial release of tangential stress during maturation. Consistence with data and with finite element computation in the case of a square fibre confirmed that, because of the unrestrained radial condition, a large part of the tangential maturation stress is released in situ.
Keywords: anisotropy; boundary conditions; cell-wall maturation; growth strain; multilayer model; residual stress; wood fibre
|
|
|
Gourlet-Fleury, S., Comu, G., Jesel, S., Dessard, H., Jourget, J. G., Blanc, L., et al. (2005). Using models to predict recovery and assess tree species vulnerability in logged tropical forests: A case study from French Guiana. For. Ecol. Manage., 209(1-2), 69–86.
Abstract: A major challenge for forest managers is to define the optimal cutting cycle to ensure that the resource is sustained in the long term. Matrix models of forest dynamics allow time-projection of diameter-class distributions and thus assessment of the time needed, after logging, to recover a given part of the exploitable stock. They are easy to build and they only require, as input variables, the diameter structure of the population(s) under scope. However, such models are based on a coarse description of tree population dynamics and must be used with caution. In particular, as trees are only described from a diameter threshold (usually 10 cm dbh), recruitment of a new tree cannot be linked with the preceding generation since too much time elapsed between seed dispersal and the installation of a 10-cm recruit. This causes predictions of matrix models to be highly questionable in the long term when ingrowth to larger dbh classes greatly depends on the way recruitment has been modelled. We used a case study from French Guiana to test whether or not a simple matrix model is reliable enough to help forest managers choose between management alternatives. We focused on the major timber species Dicorynia guianensis Amshoff (Caesalpiniaceae) harvested under a selective cutting regime. We compared predictions of D. guianensis stock recovery in the short and long term provided by two models: StoMat, a non-regulated matrix model, and SELVA, a single-tree distance dependent model explicitly simulating the entire species life cycle. Both models were independently calibrated on data from Paracou permanent sample plots. We showed that: (i) the short-term recovery of the exploitable stock predicted by StoMat is reliable for a large range of disturbance conditions; (ii) recruitment implementation in StoMat does not influence projections until the third felling cycle; (iii) for shared initial stand conditions SELVA and StoMat give consistent mid- and long-term predictions: the simple recruitment model used into StoMat could efficiently summarise the regeneration processes of the species under low felling intensity. Our results indicate that the current felling regime used in French Guiana may not be sustainable on a long-term basis. In any case, no more than 60% of the initial stock would be recovered after logging. We conclude that simple models can provide as reliable predictions as more complicated ones. They may be sufficient to assess the recovery of a species' exploitable stock even in the long term, or at least assess the (un)sustainability of particular harvesting regimes. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: matrix model; individual-based spatially explicit model; regeneration; recruitment; long-term population dynamics
|
|
|
Scotti-Saintagne, C., Mariette, S., Porth, I., Goicoechea, P. G., Barreneche, T., Bodenes, K., et al. (2004). Genome scanning for interspecific differentiation between two closely related oak species [Quercus robur L. and Q petraea (Matt.) Liebl.]. Genetics, 168(3), 1615–1626.
Abstract: Interspecific differentiation values (G(ST)) between two closely related oak species (Quercus petraea and Q. robur) were compiled across different studies with the aim to explore the distribution of differentiation at the genome level. The study was based on a total set of 389 markers (isozymes, AFLPs, SCARs, microsatellites, and SNPs) for which allelic frequencies were estimated in pairs of populations sampled throughout the sympatric distribution of the two species. The overall distribution of GST values followed an L-shaped curve with most markers exhibiting low species differentiation (G(ST) < 0.01) and only a few loci reaching >10% levels. Twelve percent of the loci exhibited significant G(ST) deviations to neutral expectations, suggesting that selection contributed to species divergence. Coding regions expressed higher differentiation than noncoding regions. Among the 389 markers, 158 could be mapped on the 12 linkage groups of the existing Q. robur genetic map. Outlier loci with large G, values were distributed over 9 linkage groups. One cluster of three outlier loci was found within 0.51 cM; but significant autocorrelation of GST was observed at distances <2 cM. The size and distribution of genomic regions involved in species divergence are discussed in reference to hitchhiking effects and disruptive selection.
|
|
|
Degen, B., Bandou, E., & Caron, H. (2004). Limited pollen dispersal and biparental inbreeding in Symphonia globulifera in French Guiana. Heredity, 93(6), 585–591.
Abstract: 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, t(m), 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 1.3 trees/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.
Keywords: gene flow; microsatellites; mixed mating; spatial autocorrelation; tropical tree; twogener
|
|
|
Scotti-Saintagne, C., Bodenes, C., Barreneche, T., Bertocchi, E., Plomion, C., & Kremer, A. (2004). Detection of quantitative trait loci controlling bud burst and height growth in Quercus robur L. Theor. Appl. Genet., 109(8), 1648–1659.
Abstract: Genetic variation of bud burst and early growth components was estimated in a full-sib family of Quercus robur L. comprising 278 offspring. The full sibs were vegetatively propagated, and phenotypic assessments were made in three field tests. This two-generation pedigree was also used to construct a genetic linkage map (12 linkage groups, 128 markers) and locate quantitative trait loci (QTLs) controlling bud burst and growth components. In each field test, the date of bud burst extended over a period of 20 days from the earliest to the latest clone. Bud burst exhibited higher heritability (0.15-0.51) than growth components (0.04-0.23) and also higher correlations across field tests. Over the three tests there were 32 independent detected QTLs (Pless than or equal to5% at the chromosome level) controlling bud burst, which likely represent at least 12 unique genes or chromosomal regions controlling this trait. QTLs explained from 3% to 11% of the variance of the clonal means. The number of QTLs controlling height growth components was lower and varied between two and four. However the contribution of each QTL to the variance of the clonal mean was higher (from 4% to 19%). These results indicate that the genetic architecture of two important fitness-related traits are quite different. On the one hand, bud burst is controlled by several QTLs with rather low to moderate effects, but contributing to a high genetic (additive) variance. On the other hand, height growth depends on fewer QTLs with moderate to strong effects, resulting in lower heritabilities of the trait.
|
|
|
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.
|
|
|
Amusant, N., Beauchene, J., Fournier, M., Janin, G., & Thevenon, M. F. (2004). Decay resistance in Dicorynia guianensis Amsh.: analysis of inter-tree and intra-tree variability and relations with wood colour. Ann. For. Sci., 61(4), 373–380.
Abstract: Dicorynia guianensis Amsh. is very widespread in the forests of French Guiana and moreover is the leading species harvested in this area, but its main defect remains the great variability of wood durability, especially with respect to fungal decay. The aim of this work was to study this inter- and intra-tree variability in order to identify the parameters responsible for this variation (growth area, height and radial position) within the tree. The resistance decrease from the outer heartwood to the pith. Measurement of colour variation using the CIELAB (L*, a*, b*, C*, h*) system was performed at the intra-tree level to highlight the longitudinal and radial gradients of variation. Dicorynia guianensis becomes less red and dark from the outer to the inner heartwood and from the base to the top. Lastly, variations of colour and durability were correlated: the wood is less resistant the redder and darker it is.
Keywords: Dicorynia guianensis; Amazonian wood; wood colour/decay resistance; heartwood; variability
|
|
|
Stien, D., & Gastaldi, S. (2004). Design of polyaromatic hydrocarbon-supported tin reagents: A new family of tin reagents easily removable from reaction mixtures. J. Org. Chem., 69(13), 4464–4470.
Abstract: We report in this paper the preparation and use of stannanes 11, 12a, and 12b, compounds whose 3-pyrenylpropyl side chain affinity for activated carbon simplifies tin removal and product isolation. Our pyrene-supported reagents can be used for radical reductions and cyclizations (11), radical and cationic allylations (12a), and Stille couplings (12b) in much the same way as tributyltin derivatives.
|
|
|
Degen, B., & Roubilk, D. W. (2004). Effects of animal pollination on pollen dispersal, selfing, and effective population size of tropical trees: A simulation study. Biotropica, 36(2), 165–179.
Abstract: Animals, especially insects, are principal pollen vectors of tropical trees and have behavior patterns that affect gene dispersal. Here, we explore complex pollination systems using a new simulation model Eco-Gene and considering, among other factors, flowering synchrony. spatial distribution of trees, degree of selfing, population densities, pollinator flight distances, pollen deposition, and pollinator response to floral display size. Sensitivity analyses using two contrasting tree data sets (Jacaranda copaia and Dipteryx odorata) determined the importance of each parameter on three response variables: the proportion of seeds from self-pollination, effective population size, and pollen dispersal. Spatial considerations and attractiveness of floral displays were prominent features determining the population genetic result of pollinators, and some biological implications of the results are discussed.
Keywords: Amazon; bees; Brazil; Dipteryx; Jacaranda; model; pollination; sensitivity analysis; trees
|
|