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International audience; This work assesses the potential of stinging nettle (Urtica dioica L.) growing on trace element contaminated soils to produce fibres for material applications. The nettles studied in this work grew spontaneously and dominated the vegetation cover in poplar short rotation coppices planted for the phytomanagement of lands contaminated by trace elements. Two sites were studied, contaminated by Hg for the first one and a mix of As, Cd, Pb and Zn for the second one. Results show that, for the considered soils, the contaminant contents in nettle bast fibres were at low levels, comparable to those collected at unpolluted control areas. It makes it possible to consider this biomass for material use. The measured matter yield was lower than those obtained with traditional fibre crops cultivated in Europe on agricultural lands. However, the tensile properties of the bast fibres mechanically extracted without field retting or prior alkaline treatment were equal to or better than those of industrial hemp and flax, making spontaneous nettles an interesting supplement to traditional European fibre crops for material applications.

Although eucalypts are the most planted hardwood trees worldwide, the majority of them are frost sensitive. The recent creation of frost-tolerant hybrids such as Eucalyptus gundal plants (E. gunnii × E. dalrympleana hybrids), now enables the development of industrial plantations in northern countries. Our objective was to evaluate the impact of cold on the wood structure and composition of these hybrids, and on the biosynthetic and regulatory processes controlling their secondary cell-wall (SCW) formation. We used an integrated approach combining histology, biochemical characterization and transcriptomic profiling as well as gene co-expression analyses to investigate xylem tissues from Eucalyptus hybrids exposed to cold conditions. Chilling temperatures triggered the deposition of thicker and more lignified xylem cell walls as well as regulation at the transcriptional level of SCW genes. Most genes involved in lignin biosynthesis, except those specifically dedicated to syringyl unit biosynthesis, were up-regulated. The construction of a co-expression network enabled the identification of both known and potential new SCW transcription factors, induced by cold stress. These regulators at the crossroads between cold signalling and SCW formation are promising candidates for functional studies since they may contribute to the tolerance of E. gunnii × E. dalrympleana hybrids to cold.

Hydrophobic properties were conferred to a high-lignin-content Kraft pulp by a laccase-catalysed treatment in the presence of lauryl gallate (LG). The treatment resulted in a two-fold increase in contact angle and conferred water absorption resistance to the pulp. Kappa number was increased, indicating that some phenolic compounds were incorporated in the pulp. A control treatment with LG alone did not affect water absorption, demonstrating that laccase was essential to attain these new properties. The loss of hydrophobicity after an acetone Soxhlet extraction highlighted that adsorbed acetone-soluble compounds played a key role in the properties. GC-FID and HPSEC-UV analysis of the acetone extract indicated the formation of dodecanol and different phenolic oligomers. SEM images showed the treatment-induced changes in the fibre network. Additional experiments with various reaction times and reactant concentrations highlighted the role of LG oxidation products in the introduction of absorption resistance. (C) 2013 Elsevier B.V. All rights reserved.

Key message Molecular markers were used for paternity recovery in a maritime pine (Pinus pinasterAit.) polycross trial, facilitating forward selection. Different breeding strategies for seed orchard establishment were evaluated by comparing genetic gains and diversity. This work opens up new perspectives in maritime pine breeding.[br/] Context Polycross mating designs are widely used in forest tree breeding to evaluate parental breeding values for backward selection. Alternatively, polycross progeny trials may be used to select the best trees on the basis of individual breeding values and molecular pedigree analysis.[br/] Aims This study aimed to test such a forward selection strategy for the maritime pine breeding program.[br/] Methods In a maritime pine polycross trial, progeny with higher breeding values for growth and stem straightness was first preselected with or without relatedness constraints. After paternity recovery, the preselected trees were ranked on the basis of their breeding values, estimated from the recovered full pedigree. Finally, the best candidates were selected with three different strategies (forward, backward, mixed) and three levels of coancestry constraints to establish a virtual clonal seed orchard.[br/] Results Complete pedigrees were successfully recovered for most of the preselected trees. There was no major difference in expected genetic gains between the two preselection strategies which differed for relatedness constraints. Genetic gains were slightly higher for forward selection than for classical backward selection.[br/] Conclusion This seminal study opens up new perspectives for using forward selection within the French maritime pine breeding program. [br/]

ACT; International audience; Using low emissive materials in building is an effective way to reduce indoor concentrations of pollutants such as VOCs. Material emissions are assessed by the ISO 16000-9 standard. This procedure is time-consuming and is not suitable for on-site measurements. This work aimed in assessing an alternative method, DOSEC®-SPME, for simple measurements. To validate it, emissions of 30 materials were characterized by both ISO 16000-9 and DOSEC®-SPME. A first correlation was found between the two methods for formaldehyde emissions of raw materials. This encouraging result allows considering the development of new decision making tools for the selection of healthy building materials.

Food contact surfaces are subject to contamination by pathogens, which can lead to cross-contamination by transfer to other food products. However, the European regulation specifies that materials intended for safe food contact must not interfere with foodstuff characteristics. Considered a traditional and natural material, wooden boards are used as a “technological tool” during the cheese-ripening process. In France, wood is authorized for food-contact. The aim of this study was to determine the behavior of deliberately contaminated wooden surfaces in direct contact with foodstuffs. The model studied consisted of spruce ripening shelves experimentally inoculated with a well-known potential hazard throughout the production chain of some dairy products: Listeria monocytogenes . Then, the transfer from deliberately inoculated wood to cheese was analyzed and compared with plastic and glass inoculated surfaces. For this purpose, a protocol was developed and first-use spruce boards were inoculated with L. monocytogenes solution at a concentration of 10 5 CFU/cm 2 then the microbial transfer to pressed non-cooked cheeses was studied. Factors such as cheese contact time, wood and cheese moisture contents, were tested. We compared the transfer rate with glass plates and plastic sheets with inclined meshes, commonly used throughout the cheese production chain, in the same conditions. The results showed a transfer yield below 3% (CFU/cm 2 ) in the first hour of contact for all surfaces tested and was 0.55% for the wooden boards. No differences were found for drier cheeses or for higher wood moisture content. The wooden porous surface in contact with cheeses was not a factor that increased the L. monocytogenes direct transfer rates. In conclusion, wooden shelves have the lowest transfer rate of L. monocytogenes to pressed non-cooked cheeses compared to glass and polypropylene surfaces. This results contribute to the suitability of use of wooden material for direct contact with food.

International audience; Wood furniture is often composed of simple parts that may be modeled as beams or plates. These particularities allow using simplified approaches that reduces the number of degrees of freedom (dof for short) in a finite element simulation of the furniture's behavior. Generally, connections are not taken into account in such simulations but these connections are critical in the failure process of the furniture and it worth studying it precisely. Using a multi-scale approach, this paper introduces a numerical procedure to identify the connection contribution in the furniture's stiffness. Comparing 3D finite element calculations with a Timoshenko's beam calculation on a corner of two wooden parts, we identify the specific behavior of the connection elements (pins, nut, screw… and local 3D effects) to introduce it as a punctual 0D element in the beam code. Two validations of the approach are presented here: (i) a numerical validation by comparing the result of the beam code with a complete 3D finite element simulation on a representative plane structure of wooden furniture; (ii) an experimental validation by managing a global bending test and measuring the displacement field using digital image correlation (DIC for short).

Chapitre 8; Genome-wide profiling (transcriptomics, proteomics, metabolomics) is providing unprecedented opportunities to unravel the complexity of coordinated gene expression during embryo development in trees, especially conifer species harbouring “giga-genome”. This knowledge should be critical for the efficient delivery of improved varieties through seeds and/or somatic embryos in fluctuating markets and to cope with climate change. We reviewed “omics” as well as targeted gene expression studies during both somatic and zygotic embryo development in conifers and tentatively puzzled over the critical processes and genes involved at the specific developmental and transition stages. Current limitations to the interpretation of these large datasets are going to be lifted through the ongoing development of comprehensive genome resources in conifers. Nevertheless omics already confirmed that master regulators (e.g. transcription and epigenetic factors) play central roles. As in model angiosperms, the molecular regulation from early to late embryogenesis may mainly arise from spatio-temporal modulation of auxin-, gibberellin- and abscisic acid-mediated responses. Omics also showed the potential for the development of tools to assess the progress of embryo development or to build genotype-independent, predictive models of embryogenesis-specific characteristics.

Chapitre 7; This review compiles research results published over the last 14 years on conifer somatic embryogenesis (SE). Emphasis is placed on the newest findings that affect the response of seed embryos (typical explants) and shoot primordia (rare explants) to the induction of SE and long-term culture of early somatic embryos. Much research in recent years has focused on maturation of somatic embryos, with respect to both yield and quality, as an important stage for the production of a large number of vigorous somatic seedlings. Attempts to scale up somatic embryo production numbers and handling have resulted in a few bioreactor designs, the utility of which may prove beneficial for an industrial application. A few simplified cryopreservation methods for embryonal masses (EM) were developed as a means to ensure cost-efficient long-term storage of genotypes during clonal field testing. Finally, recent long-term studies on the growth of somatic trees in the field, including seed production yield and comparison of seed parameters produced by somatic versus seed-derived trees, are described.

International audience; The objective of this study is to improve evaluations of the future use of biomass sources in Sweden and France by representing the high spatial variations of the supply and cost of biomass sources in energy system models. The proposed methodology considers a high spatial disaggregation of biomass supply sources, as well as detailed biomass cost-supply curves, and is thereby able to account for spatial differences in heterogeneous land qualities, management strategies, and possible adaptation rates. Integrating the methodology into national or regional energy system models will enhance cost-effective evaluations of biomass sources as well as the development of the bioenergy sector. A TIMES energy system model was used to evaluate bioenergy production potential for France and Sweden based on domestic biomass sources and under the assumption that bioenergy production should not be at the expense of domestic food and forestry supply. Results show that by 2050, the biomass sources considered could provide as much as 250PJ of bioenergy in Sweden, and 1470PJ of bioenergy in France. Results further showed that 1st generation biofuels are likely to continue to play a substantial role in the biofuel mix. While 2nd generation biofuel production in Sweden is likely to be low, larger amounts of 2nd generation biofuels could be produced in France. However, the amount and type of 2nd generation biofuel produced in France was found to be highly dependent on the bioenergy demand level.

This work has been conducted under Research Infrastructure Concerted Action “Treebreedex” (http://treebreedex.eu, contract RICA-CT-2006-026076).; Vegetative propagation of forest trees offers advantages to both tree breeders and the forest industry. This review will describe benefits, type of vegetative propagation, and its integration into breeding programmes. Of all of the different methods for vegetative propagation, only rooted cuttings and somatic embryogenesis (and the combined use of both) offer any practical methods for large-scale commercial use. However, it is very difficult to fully appreciate the overall level of activity of the research and application of somatic embryogenesis of forest trees. Publications and reports only highlight a small fraction of the ongoing work. To this end, a survey was conducted across Europe (under EU Research Infrastructure Concerted Action “Treebreedex”) to document the species involved, the state-of-the-art of somatic embryogenesis, its stage of development and its application in tree improvement programmes and to commercial forestry. The results of this survey are presented and discussed. In addition, this review presents the challenges (biological, economic, public acceptance and regulatory) and their relationships to European forestry. Finally, a strategy to promote the use of this technology is proposed.

Producing hard carbon from lignocellulosic biomass has been the focus of recent studies as a promising source of anode material for Na-ion batteries. Woody biomass is a potential source, but it is already well valorized. Consequently, river driftwood can be an excellent alternative, especially since it is a disturbing waste for dam regulators. It can jeopardize dam safety, damage intake works, and sink in reservoirs, lowering water quality and decreasing reservoir volume. We examine the potential of river driftwood as a source of hard carbon for Na-ion batteries. Hydrothermal carbonization (HTC) was carried out at temperatures between 180 and 220 ◦C as the first step to produce hydrochar followed by an upgrading pyrolysis step at 1400 ◦C under an inert atmosphere to obtain hard carbon. We investigated the effect of HTC operational conditions and driftwood biomass (genera) on hydrochar and hard carbon properties, as well as the latter’s impact on Na-ion batteries. The produced carbon electrodes delivered a reversible capacity of 270–300 mAh⋅g-1 for the first cycle and showed high coulombic efficiencies of 77–83%. We also observed promising cyclability of a maximum 2% loss after 100 cycles. Moreover, results suggest that obtained hard carbon can compete with commercial materials and is capable to supply large battery factories with anode material.

International audience; Laccase-treated wood fibres were tested for small-scale wet-process manufacture of hardboards. Two laccases of distinct redox potentials, one from Pycnoporus cinnabarinus and one from Myceliophthora thermophila, were compared in terms of their effect on the physical-chemical properties of the treated fibres and hardboards. Wood fibres were produced from Norway spruce (Picea abies) by thermomechanical pulping. The thermomechanical pulp was treated with each laccase in parallel, in the presence or absence of the synthetic laccase mediator 1-hydroxybenzotriazole (HBT). High-performance size-exclusion chromatography revealed that the ethanolic extractable phenolic compounds in the fibres underwent oligomerization upon enzymatic treatment, and that the extent of oligomerization was dependent on the enzyme source and concentration and on the presence or absence of mediator. Lower lignin oligomerization levels led to higher (up to twofold) fibre internal bonding, whereas higher lignin oligomerization levels led to higher fibre hydrophobisation. X-ray photoelectron spectroscopy revealed a significant change in surface lignin content. These results demonstrate pre-treatment of spruce fibres with laccase-mediator systems prior to hot processing can improve the mechanical resistance of hardboards while using lower amounts of enzyme.

The relation between lignin-related structure and antifungal activities was assessed against the white-rot fungus Trametes versicolor and two brown-rot fungi, Coniophora puteana and Rhodonia placenta. Various aromatic compounds were used to study the effect of lignin-related products. Guaiacyl and p-hydroxyphenyl units have hold greater antifungal properties than syringyl units. The presence of carbonyl and conjugated double bond increased inhibition of fungal growth, thus, highlighting the importance of the propyl chains. Furthermore, the alkylation either on phenolic or carboxylic acid moieties strongly increased fungicidal activities.

SSCI-VIDE+CDFA+LDJ; International audience; Several lignin samples of varying botanical nature (softwood, hardwood, or annual plants) and extraction procedures (Kraft, Organosolv, or soda) were fully characterized by complementary techniques and engaged in “catalyst-free” depolymerization in air under basic conditions. Treatment of the complex reaction mixture was optimized to ensure reproducibility, careful analyses, and accurate data. After an optimization of the reaction conditions, we were able to recover high amounts of aromatic compounds (up to 19%wt). Additionally, we demonstrated a relation between lignin’s structure, i.e., the accessible phenol moieties and inter-unit linkages, and the yields of aromatic compounds, thus showing the importance of the extraction process to optimize lignin’s potential. This work provides valuable reference for developing further lignin depolymerization under basic media.

Aim of study: Adaptation of silviculture in planted forest may help to mitigate damage due to biotic and abiotic hazards. However, compromises have to be found because it is not possible to minimize the risk from all hazards through application of a single forest management approach. The objective of this study was to improve a multi-criteria risk analysis (MCRA) method that makes it possible to rank forest management alternatives (FMAs) according to multiple risks. Material and Methods: We defined eight FMAs for maritime pine forests in France, Spain and Portugal. We used as the definition of risk the combination of hazard, susceptibility and exposure. Hazard level was estimated using archive data on occurrence and severity of damaging agents over the last few decades. Forest susceptibility to hazards was evaluated by experts who scored the effect on stand resistance of eleven silvicultural operations characterizing each FMA. Exposure was estimated as value at stake, which combined forest standing volume, simulated with forest growth models, and wood prices.Main Results: Using the PROMETHEE algorithm, we found that the overall ranking of FMAs was consistent across all countries, with short rotation plantations to produce pulpwood or energy wood were the least at risk. The ranking was mainly driven by forest values at stake. We found that by improving the accuracy of forest values exposed to damage, based on growth models and representative wood prices, the MCRA outcomes were more useful and realistic.Research highlights: Our methodology provides a relevant framework to design FMAs that would minimize risks while maintaining income.Keywords: Pinus pinaster; vulnerability; hazards; growth modelling; expert assessment; wood price; southwestern Europe.

Douglas-fir is a conifer species of major economic importance worldwide, including Western Europe and New Zealand. Herein we describe some characterization and significant refinement of somatic embryogenesis in Douglas-fir, with focus on maturation. The most typical structures observed in the embryonal masses were large polyembryogenic centres (up to 800-1500 μm) with a broad meristem, creating a compact ce ll “package” with suspensor cells. Singulated somatic embryos composed of both a embryonal head (300-400 μm) and long, tightly arranged suspensor were also frequent. Embryo development was enhanced following embryonal mass dispersion on filter paper discs at low density (50-100 mg fresh mass). Moreover, increasing gellan gum concentration in maturation medium (up to 10 g L-1) improved both the quantity and quality of cotyledonary somatic embryos (SEs), which were subsequently able to germinate and develop into plantlets at high frequency. Embryogenic yield was highly variable among the seven embryogenic lines tested (27-1544 SE g-1 fresh mass). Interestingly secondary somatic embryogenesis could be induced from cotyledonary SEs of both low- and highly-productive lines with some useful practical outcomes: secondary lines from low-performance lines (30-39 478 SE g-1) displayed significantly higher embryogenic yield (148-1343 SE g-1). In our best conditions, the total protein content in cotyledonary SEs increased significantly with maturation 41 duration (up to 150 μg mg-1 fresh mass after 7 weeks) but remained below that of mature zygotic embryos (300 μg mg-1). The protein pattern was similar in both somatic and zygotic embryos, with major storage proteins identified as 7S-vicilin- and legumin-like proteins.

International audience; AbstractKey messageA moderate genetic diversity, the absence of a significant genetic differentiation between wild and cultivated stands and a highly admixed genetic structure of sweet chestnut with two main clusters were observed in France using two different data sets with 10 and 18 microsatellites.ContextRenewed interest in European chestnut in France is focused on finding locally adapted populations partially resistant to ink disease and identifying local landraces.AimsWe genotyped trees to assess (i) the genetic diversity of wild and cultivated chestnut across most of its range in France, (ii) their genetic structure, notably in relation with the sampled regions, and (iii) to a lesser extent the relations between French chestnuts with 10 cultivated chestnuts from the Northwest of Spain that were previously classified in the Iberian or Italian groups.MethodsA total of 693 trees in 16 sampling regions in France were genotyped at 24 SSRs and 1401 trees in 17 sampling regions at 13 SSRs.ResultsGenetic diversity was moderate in most sampling regions, with redundancy between them. No significant differentiation was found between wild and cultivated chestnut. A genetic structure analysis with no a priori information found a low yet significant structure and identified two clusters at 18 SSRs. One cluster gathers trees from south-east France and Corsica (RPP1), and another cluster gathers trees from all other sampled regions (RPP2). A substructure was detected at 10 SSRs suggesting differentiation within both RPP1 and RPP2. RPP1 was split between south-east France and Corsica. RPP2 was split between northwest France, Aveyron, Pyrenees, and a last cluster gathering individuals from several other regions.ConclusionThe genetic structure within and between our sampling regions is likely the result of natural events (recolonization after the last glaciation) and human activities (migration and exchanges). These advances on our knowledge of chestnut genetic diversity and structure will benefit conservation and help our local partners’ valorization efforts.

International audience; Launched in 1987, the French National Programme for the Conservation of Native Elm Genetic Resources focused on the ex situ conservation of clones of adult field elms (Ulmus minor Mill.) survivors of the Dutch elm disease (DED) pandemic. It was later expanded to include the in situ dynamic conservation of populations of European white elm (U. laevis Pall.) and wych elm (U. glabra Huds.). The national collection contains 441 clones, partly characterized and evaluated in a European project. The pathological tests and experimental plantations did not reveal clones truly resistant to DED but provided material for the restoration of hedgerows. Two conservation units of white elm and one of wych elm were selected, enriching the pan-European EUFORGEN network for dynamic conservation of forest genetic resources. This programme provides feedback on genetic conservation strategies for forest trees in a health crisis. New partners are invited to make use of the scientific potential of the clone bank and experimental plots.

International audience; This work assesses the potential of nettle (Urtica dioica L.) fibers produced on contaminated lands for composite applications. The nettles studied in this work grew spontaneously and in a prevalent manner in poplar short rotation coppice planted for the phytomanagement of a land contaminated by traces of metals. Results show that the contaminant contents in nettle bast fibers are low: only traces were measured. It makes it possible to consider this biomass for material use. The measured matter yield is lower than those obtained with traditional fiber crops cultivated in Europe on agricultural lands but the tensile properties of the bast fibers are equal to or better than those of hemp and flax, making spontaneous nettle an interesting supplement to traditional European fiber crops for composite applications

International audience; To make intensive bioenergy poplar plantations attractive on an economic and environmental point of view, their sustainable resource management is mandatory. These plantations are indeed often installed on marginal lands to avoid competition with food agriculture and large amounts of nutrients are repeatedly exported in the young harvested biomass. Besides the application of organic residues to reclaim impoverished soils, the use of species or genotypes efficiently using nutrients, and especially nitrogen, is also a way to slow down fertility losses in short-rotation poplar plantations. Our goal in the present study was to document the genotypic variability available in terms of yield, nitrogen-use efficiency (NUE), and nitrogen export rate, the links between these traits, and their plasticity in response to contrasting site conditions and during two rotations in a wide set of Populus deltoides × Populus nigra genotypes. A wide range of variation has been highlighted for biomass production, tree dimensions, and nitrogen use and export at both sites, and particularly at the most productive one. Environmental and genotype by environment effects were very strong and the ranking of genotypes was not maintained between the two sites for most studied traits. Because of climatic conditions less contrasted between sites during the second rotation, the differences were less marked than during the first rotation. The most productive and efficient genotypes to use nitrogen were also those responsible for the highest nitrogen exports during harvest. Indeed, although the most productive genotypes had high NUE, their high biomass production resulted in a more important nitrogen export at harvest than the less productive genotypes.

Key message This review highlights some of the discoveries and applications made possible by “omics” technologies over the last 10 years and provides perspectives for pioneering research to increase our understanding of tree biology. Context A decade after the first forest tree genome sequence was released into the public domain, the rapidly evolving genomics and bioinformatics toolbox has advanced our understanding of the structure, functioning, and evolution of forest tree genomes. Aims and methods This review highlights some of the discoveries and applications that “omics” technologies have made possible for forest trees over the past 10 years. Results In this review, we start by our current understanding of genome evolution and intricacies of gene regulation for reproduction, development, and responses to biotic and abiotic stresses. We then skim over advances in interactome analysis and epigenomics, the knowledge of the extent of genetic variation within and between species, revealing micro- and macro-evolutionary processes and species history, together with the complex architecture of quantitative traits. We finally end with applications in genetic resource conservation and breeding. Conclusion The knowledge gained through the use of these technologies has a huge potential impact for adapting forests to the main challenges they will have to face: changing demand from ecosystem services with potentially conflicting strategies in terms of conservation and use, as well as climate changes and associated threats. Genomics will undoubtedly play a major role over the next decade and beyond, not only to further understand the mechanisms underlying adaptation and evolution but also to develop and implement innovative management and policy actions to preserve the adaptability of natural forests and intensively managed plantations.

Background Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that cleave polysaccharides through an oxidative mechanism. These enzymes are major contributors to the recycling of carbon in nature and are currently used in the biorefinery industry. LPMOs are commonly used in synergy with cellulases to enhance biomass deconstruction. However, there are few examples of the use of monocomponent LPMOs as a tool for cellulose fibrillation. In this work, we took advantage of the LPMO action to facilitate disruption of wood cellulose fibers as a strategy to produce nanofibrillated cellulose (NFC). Results The fungal LPMO from AA9 family (PaLPMO9E) was used in this study as it displays high specificity toward cellulose and its recombinant production in bioreactor is easily upscalable. The treatment of birchwood fibers with PaLPMO9E resulted in the release of a mixture of C1-oxidized oligosaccharides without any apparent modification in fiber morphology and dimensions. The subsequent mechanical shearing disintegrated the LPMO-pretreated samples yielding nanoscale cellulose elements. Their gel-like aspect and nanometric dimensions demonstrated that LPMOs disrupt the cellulose structure and facilitate the production of NFC. Conclusions This study demonstrates the potential use of LPMOs as a pretreatment in the NFC production process. LPMOs weaken fiber cohesion and facilitate fiber disruption while maintaining the crystallinity of cellulose. Electronic supplementary material The online version of this article (10.1186/s13068-019-1501-0) contains supplementary material, which is available to authorized users.

International audience; Somatic embryogenesis techniques have been developed for most coniferous species, but only using very juvenile material. To extend the techniques' scope, better integrated understanding of the key biological, physiological and molecular characteristics of embryogenic state is required. Therefore, embryonal masses (EMs) and non-embryogenic calli (NECs) have been compared during proliferation at multiple levels. EMs and NECs originating from a single somatic embryo (isogenic lines) of each of three unrelated genotypes were used in the analyses, which included comparison of the lines' anatomy by transmission light microscopy, transcriptomes by RNAseq Illumina sequencing, proteomes by free-gel analysis, contents of endogenous phytohormones (indole-3-acetic acid, cytokinins and ABA) by LC-MS analysis, and soluble sugar contents by HPLC. EMs were characterized by upregulation (relative to levels in NECs) of transcripts, proteins, transcription factors and active cytokinins associated with cell differentiation accompanied by histological, carbohydrate content and genetic markers of cell division. In contrast, NECs were characterized by upregulation (relative to levels in EMs) of transcripts, proteins and products associated with responses to stimuli (ABA, degradation forms of cytokinins, phenols), oxidative stress (reactive oxygen species) and carbohydrate storage (starch). Sub-Network Enrichment Analyses that highlighted functions and interactions of transcripts and proteins that significantly differed between EMs and NECs corroborated these findings. The study shows the utility of a novel approach involving integrated multi-scale transcriptomic, proteomic, biochemical, histological and anatomical analyses to obtain insights into molecular events associated with embryogenesis and more specifically to the embryogenic state of cell in Douglas-fir.

International audience; Wood recycling is common practice in most countries. Currently, recovered wood is used for relatively low value uses including energy generation, particleboard manufacture, animal beddings and landscape uses. This paper gives an overview of two research projects that aim to generate high-value products from recovered wood and thereby encourage even higher rates of wood recycling. One project is concerned with the extraction of nano-crystalline cellulose from waste MDF and the other produces laminated beams from recovered wood.

International audience; This work aims at designing functional biomaterials through selective chemical modification of xylan from beechwood. Acidic hydrolysis of xylan leaded to well-defined oligomers with an average of six xylose units per chain and with an aldehyde group at the reductive end. Reductive amination was performed on this aldehyde end-group to introduce an azide reactive group. 'Click chemistry' was then applied to couple these hydrophilic xylans moieties with different hydrophobic fatty acid methyl esters that were previously functionalized with complementary alkyne functions. The resulting amphiphilic bio-based conjugates were then self-assembled using three different methods, namely direct solubilization, thin-film rehydration/extrusion and microfluidics. Well -defined micelles and vesicles were obtained and their high loading capacity with propiconazole as an antifungal active molecule was shown. The resulting vesicles loaded with propiconazole in a microfluidic process, proved to significantly improve the antifungal activity of propiconazole, demonstrating the high potential of such xylan-based amphiphiles.

Made available in DSpace on 2018-12-11T16:53:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-10-15 The use of microbial enzyme cocktails for the conversion of polysaccharides of plant origin into fermentable sugars is a global trend. The objectives of this study were to optimize the production of cellulases and hemicellulases by the fungus Lichtheimia ramosa, evaluate the catalytic properties of the produced enzymes, and apply these biocatalysts in the saccharification of sugarcane bagasse. The production of carboxymethylcellulase (CMCase), β-glucosidase, xylanase, and β-xylosidase by L. ramosa were 168.1 ± 2.2, 270.4 ± 8.9, 34 ± 0.8, and 199.2 ± 2.6 U/g of dry substrate, respectively. The optimum pH for the activity of the enzymes ranged between 4.5 and 5.5, and the optimum temperature varied between 55 °C and 65 °C. The enzymes were stable within a wide range of pH, and approximately 95% of their original activity was preserved when incubated for 1 h at 55 °C. The half-lives (t1/2) of CMCase, β-glucosidase, xylanase, and β-xylosidase were 68, 59, 52, and 54 min, respectively, when incubated at 60 °C. The enzymes were stable in solutions containing ethanol (10%), and the kinetic parameters (Km and Vmax) demonstrated that β-glucosidase from L. ramosa was competitively inhibited by glucose. The enzyme extract produced by L. ramosa was used for the saccharification of sugarcane bagasse pretreated with glycerol and the highest yield of glucose (10.66%) was obtained at 24 h of hydrolysis. The characteristics of the enzymes, combined with the efficiency in hydrolyzing sugarcane bagasse, allow for the application of this enzyme extract to processes of cellulose saccharification for the production of second-generation ethanol. Laboratory of Enzymology and Fermentation Processes Faculty of Biological and Environmental Sciences Federal University of Grande Dourados (FCBA/UFGD) Laboratory of Microbial Enzymes São Paulo State University – UNESP/IQ Laboratory of Bioengineering Faculty of Biological and Environmental Sciences Federal University of Grande Dourados (FCBA/UFGD) Laboratory of Microbial Enzymes São Paulo State University – UNESP/IQ

International audience; Poplar crates are widely used in contact with foodstuffs. One of the major markets for poplar crates is apple packaging. As a direct food contact material, wood is subject to European regulation no 1935/2004, which requires no negative effect of material or packaging on foodstuffs. This study aims to quantify the transfer of Penicillium expansum conidia and Escherichia coli from poplar specimens to Golden apples. This [microorganisms-poplar-Golden apple] model was developed taking into account realistic parameters with extreme and usual conditions. Poplar specimens were artificially contaminated with P. expansum and E. coli. They were then put in contact with apples and stored in a climatic room for up to one week. Both wood specimens and apples were analyzed to assess the survival of microorganisms on wood specimens and the proportion of microorganism transfer to apples. Whereas P. expansum conidia survived but did not grow on wood specimens, E. coli mortality was observed after one hour of contact with wood. The proportion of both microorganisms transferred to apples was less than 0.25%. The impact of wood moisture content, contact time between wood and apples, and apple supply variability on the transfer levels were studied. The hygroscopic properties of wood were discussed. The low and reproducible transfer levels observed demonstrate that poplar is a safe packaging material for apples.

International audience; The purpose of this study is to target well-defined xylooligosaccharides by controlled sulfuric acidic hydrolysis of beechwood xylans. Parameters such as sulfuric acid and xylan concentrations, hydrolysis duration and temperature have been investigated, allowing optimum conditions to be determined (0.7 M H2SO4, 90 degrees C, 45 min). The obtained xylooligosaccharides show a well-defined structure and have been characterized using several techniques such as 1D and 2D nuclear magnetic resonance spectrometry and matrix-assisted laser desorption/ionization-time of flight mass spectrometry. This work demonstrated that mild acidic hydrolysis conditions enable the reproducible production of xylooligosaccharides containing, on average, six xylose units and only one 4-O-methyl-D-glucuronic acid unit likely positioned at the non-reductive chain-end.

The purpose of this study was to design new biomaterials based on functionalized xylan derivatives. In one approach, 4-O-methylglucuronoxylan (MGX) of beechwood was oxidized by sodium periodate (NaIO4). A ratio of 0.2 NaIO4/xylose leads to a degree of oxidation of 0.15 with 75% yield. Then, the oxidized MGX aldehyde was submitted to reductive amination reaction with benzylamine, and as a result, the xylan backbone was effectively grafted with benzyl groups with a degree of substitution of 0.11. In another approach, controlled sulfuric acidic hydrolysis of MGX was performed to get well-defined xylooligosaccharides (XOS). Then, the reductive amination reaction of the XOS aldehyde functions was performed with allylamine or 2-aminoethylazide to graft the chain ends with an allyl or an azide function, respectively. The proposed methods can open a route to the design of new functional biomaterials.

Key message The diversity of forest management systems and the contrasted competition level treatments applied make the experimental networks of the GIS Coop, a nationwide testing program in the field of emerging forestry topics within the framework of the ongoing global changes. Context To understand the dynamics of forest management systems and build adapted growth models for new forestry practices, long-term experiment networks remain more crucial than ever. Aims Two principles are at the basis of the experimental design of the networks of the Scientific Interest Group Cooperative for data on forest tree and stand growth (GIS Coop): contrasted and extreme silvicultural treatments in diverse pedoclimatic contexts. Methods Various forest management systems are under study: regular and even-aged stands of Douglas fir, sessile and pedunculate oaks, Maritime and Laricio pines, mixed stands of sessile oak, European silver fir, and Douglas fir combined with other species. Highly contrasted stand density regimes, from open growth to self-thinning, are formalized quantitatively. Results One hundred and eighty-five sites representing a total of 1206 plots have been set up in the last 20 years, where trees are measured regularly (every 3 to 10 years). The major outputs of these networks for research and management are the calibration/validation of growth and yield models and the drawing up of forest management guides. Conclusion The GIS Coop adapts its networks so that they can contribute to develop growth models that explicitly integrate pedoclimatic factors and thus also contribute to research on the sustainability of ecosystems under environmental and socio-economic changes.

This paper describes the micropropagation of Douglas-fir via somatic embryogenesis using media and methods available in the public domain. Douglas-fir is a conifer species with high and increasing interest for forest industries in both New Zealand and France. Delivery of the best trees to the forest from breeding programmes is currently constrained by an inability to effectively and reliably multiply selections through vegetative propagation. Somatic embryogenesis coupled with cryopreservation is essential biotechnology tool in conifers for scaling up variety design and production. The aim of this work was therefore to develop protocols for the initiation and proliferation of Douglas-fir embryogenic cell lines based on the modifications of previously published techniques and media available in the public domain, especially successful methods developed for P. radiata at Scion. Three years of initiation experiments have resulted in a simple and efficient protocol. Disinfection of whole cones (instead of seeds) was sufficient to prevent contamination. Immature zygotic embryos were excised from megagametophytes and placed onto a modified Litvay medium (Plant Cell Rep 4(6):325–328, 1985***). At optimal development stages of zygotic embryos, the average initiation percentage of embryogenic tissue was 69.3% when our most effective protocol was used. Proliferation of initiated cell lines on a Glitz formulation was challenging, with a high percentage of cell lines composed of a mixture of both embryonal masses and callus. 2,4-D at a lower concentration reduced the number of such mixed lines. Repeated liquid suspension and subculture of the embryogenic parts of the tissue was an efficient means to increase the number of embryogenic cell lines with sustained proliferation. Maltose added to the proliferation medium in place of sucrose improved fresh mass gain and consistently increased early somatic embryo patterning and growth. A sample of proliferating cell lines was successfully cryopreserved, thawed and somatic embryos were matured and germinated from these lines. The method may be of practical interest and provide new opportunities to realize increased genetic gain in this species through the clonal-assisted deployment of the best genetic material in both New Zealand and France.

International audience; Trees have a long lifespan and must continually adapt to environmental pressures, notably in the context of climate change. Epigenetic mechanisms are doubtless involved in phenotypic plasticity and in stress memory; however, little evidence of the role of epigenetic processes is available for trees growing in fields. Here, we analyzed the possible involvement of epigenetic mechanisms in the winter-dormant shoot apical meristem of Populus × euramericana clones in memory of the growing conditions faced during the vegetative period. We aimed to estimate the range of genetic and environmentally induced variations in global DNA methylation and to evaluate their correlation with changes in biomass production, identify differentially methylated regions (DMRs), and characterize common DMRs between experiments. We showed that the variations in global DNA methylation between conditions were genotype dependent and correlated with biomass production capacity. Microarray chip analysis allowed detection of DMRs 6 months after the stressful summer period. The 161 DMRs identified as common to three independent experiments most notably targeted abiotic stress and developmental response genes. Results are consistent with a winter-dormant shoot apical meristem epigenetic memory of stressful environmental conditions that occurred during the preceding summer period. This memory may facilitate tree acclimation.

Herein, we report on the preparation of novel cellulose-PEG biohybrid papers with wet strength properties. The biohybrid paper sheets are obtained using a two-step procedure where ω- or α, ω-azide functionalized PEG chains are anchored onto alkyne-functionalized wood fibers through CuAAC ligation in mild and aqueous conditions. The incorporation of the PEG grafts mostly occurs at the periphery of the cellulose fibers and degrees of substitution up to 0.028 are obtained. The presence of PEG grafts significantly increases the tensile, burst and tear strength properties in the wet state, the reinforcement being more pronounced for fibers grafted with α,ω-azide PEG. This reinforcement is consistent with a relatively sparse hetero-crosslink reaction creating inter-fiber covalent bonds and forming a cellulose network within the cell wall.

Made available in DSpace on 2018-11-26T15:44:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-04-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is one of the most important pests of cotton production worldwide. The objective of this work was to develop a sequential sampling plan for the boll weevil. The studies were conducted in Maracaju, MS, Brazil, in two seasons with cotton cultivar FM 993.A 10,000-m(2) area of cotton was subdivided into 100 of 10- by 10-m plots, and five plants per plot were evaluated weekly, recording the number of squares with feeding + oviposition punctures of A. grandis in each plant. A sequential sampling plan by the maximum likelihood ratio test was developed, using a 10% threshold level of squares attacked. A 5% security level was adopted for the elaboration of the sequential sampling plan. The type I and type II error used was 0.05, recommended for studies with insects. The adjustment of the frequency distributions used were divided into two phases, so that the model that best fit to the data was the negative binomial distribution up to 85 DAE (Phase I), and from there the best fit was Poisson distribution (Phase II). The equations that define the decision-making for Phase I are S-0 = -5.1743 + 0.5730N and S-1 - 5.1743 + 0.5730N, and for the Phase II are S-0 = -4.2479 + 0.5771N and S-1 = 4.2479 + 0.5771N. The sequential sampling plan developed indicated the maximum number of sample units expected for decision-making is similar to 39 and 31 samples for Phases I and II, respectively. Fdn MS, CP 137, BR-79150000 Maracaju, MS, Brazil Sao Paulo State Univ FCAV UNESP, Via Acesso Prof Paulo Donato Castellane,S-N, BR-14884900 Jaboticabal, SP, Brazil Embrapa Agr Oeste, CP 449, BR-79804970 Dourados, MS, Brazil Fed Univ Grande Dourados FCBA UFGD, CP 533, BR-79804970 Dourados, MS, Brazil Sao Paulo State Univ FCAV UNESP, Via Acesso Prof Paulo Donato Castellane,S-N, BR-14884900 Jaboticabal, SP, Brazil

International audience; This study proposes a model using data from a scanner (X-ray and grain angle measurements) to perform strength grading. The research also includes global measurements of modulus of elasticity (obtained by vibrations and ultrasound methods), static bending stiffness and bending strength of 805 boards of Douglas fir and 437 boards of spruce. This model can be used in an industrial context since it requires low computational time. The results of this study show that the developed model gives better results than the global non-destructive measurements of the elastic modulus commonly used in the industry. It also shows that this improvement is particularly higher in the case of Douglas fir than for spruce. The comparison has been made on both the quality of the mechanical properties assessment and on the improvement of the grading process according to the European standards by using different index.

Made available in DSpace on 2018-12-11T17:08:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-12-01 The restoration of deforested or degraded areas can contribute to biodiversity conservation and global resilience given the current and projected impacts of climate change. In recent years, a robust array of ecological restoration frameworks have been generated to address restoration challenges at large scales in different ecosystems around the world. Unfortunately, the costs associated with restoration at such scales greatly challenges the implementation of such frameworks. We used landscape ecology principles with multicriteria optimization of landscape resilience and agricultural productivity as a way to mitigate the trade-offs between production and restoration. We used the Cerrado biome in Mato Grosso do Sul State, Brazil, as a case study to apply our framework. We compared three scenarios: minimal legal compliance (MLC); selection by ecological resilience (SER); and selection by restoration cost (SRC). Our results show that increasing the restoration target from MLC (25%) to SER (30%) means moving from 968,316 to 1592 million hectares, which can represent a huge opportunity cost for agricultural lands. However, because costs and resilience are not homogeneously distributed throughout landscapes, we can select areas of intermediate ecological resilience and low cost, for the same restoration area target. This process can reduce potential conflicts and make restoration a more viable process. Our results also reveal some areas that can be particularly important for reconciling agriculture and landscape restoration. Those areas combined high and intermediate resilience and an above average profitability. This could mean that increasing restoration in this area could be very expensive, assuming that our proxy roughly represents the restoration implementation cost. However, there is another important message here, that some areas can be productive at the same time that they maintain levels of resilience above the legal compliance, which facilitates win-win scenarios in human-dominated landscapes. Faculdade de Ciências Biológicas e Ambientais FCBA/UFGD Ecologia e Conservação Campo Grande - MS Corporación para Investigaciones Biológicas Centre for Tropical Environmental and Sustainability Science College of Science and Engineering James Cook University Instituto de Biociências UNESP - Univ Estadual Paulista Rio Claro Departamento de Ecologia Departamento de Ecologia Universidade de São Paulo Centro de Engenharia Modelagem e Ciências Sociais Aplicadas Universidade Federal do ABC Ecology Evolution and Environmental Biology Columbia University Nature and Culture International Instituto de Biociências UNESP - Univ Estadual Paulista Rio Claro Departamento de Ecologia

International audience; AbstractKey messageThe application of the ITOC model allows the estimation of available biomass potentials from forests on the basis of National Forest Inventory data. The adaptation of the model to country-specific situations gives the possibility to further enhance the model calculations.ContextWith the rising demand for energy from renewable sources, up-to-date information about the available amount of biomass on a sustainable basis coming from forests became of interest to a wide group of stakeholders. The complexity of answering the question about amounts of biomass potentials from forests thereby increases from the regional to the European level.AimsThe described ITOC model aims at providing a tool to develop a comparable data basis for the actual biomass potentials for consumption.MethodsThe ITOC model uses a harmonized net annual increment from the National Forest Inventories as a default value for the potential harvestable volume of timber. The model then calculates the total theoretical potential of biomass resources from forests. By accounting for harvesting restrictions and losses, the theoretical potential of biomass resources from forests is reduced and the actual biomass potentials for consumption estimated.ResultsThe results from ITOC model calculations account for the difference between the amounts of wood measured in the forests and the actual biomass potentials which might be available for consumption under the model assumptions.ConclusionThe gap between forest resource assessments and biomass potentials which are available for consumption can be addressed by using the ITOC model calculation results.

International audience; Background: There is increasing interest in developing eucalypt stands in France for biomass energy, but the water requirements of eucalypt coppice are largely unknown.Aims: We assessed the water use and growth of two 5-year-old managed forest stands: an indigenous maritime pine stand and an introduced eucalypt stand.Methods: We used a combination of meteorological, sap flow, soil and biomass measurements, between September 2009 and July 2011.Results: The stand structure was the main driver of both water use and its partitioning between water balance components in each site. The evapotranspiration was high in the eucalypt stand, with a significant contribution of tree transpiration due to high leaf area index of the tree canopy. Under well-watered conditions, both species exhibited a similar stomatal behaviour in relation to vapour pressure deficit and, with high biomass production, the two stands presented a maximal water use efficiency in respect to their local environments and constraints. However, they experienced significant sensitivity to successive early spring and summer droughts. The unexpected prolonged soil water deficit in the eucalypt stand, induced by high water consumption and insufficient water supply, directly impacted leaf shedding and stem secondary growth. In contrast, the pines appeared conservative with respect to soil water deficits and maintained secondary growth.

Made available in DSpace on 2018-12-11T17:04:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 The present study compared the production and the catalytic properties of amylolytic enzymes obtained from the fungi Lichtheimia ramosa (mesophilic) and Thermoascus aurantiacus (thermophilic). The highest amylase production in both fungi was observed in wheat bran supplemented with nutrient solution (pH 4.0) after 96 hours of cultivation, reaching 417.2 U/g of dry substrate (or 41.72 U/mL) and 144.5 U/g of dry substrate (or 14.45 U/mL) for L. ramosa and T. aurantiacus, respectively. The enzymes showed higher catalytic activity at pH 6.0 at 60°C. The amylases produced by L. ramosa and T. aurantiacus were stable between pH 3.5-10.5 and pH 4.5-9.5, respectively. The amylase of L. ramosa was stable at 55°C after 1 hour of incubation, whereas that of T. aurantiacus maintained 60% of its original activity under the same conditions. Both enzymes were active in the presence of ethanol. The enzymes hydrolyzed starch from different sources, with the best results obtained with corn starch. The enzymatic complex produced by L. ramosa showed dextrinizing and saccharifying potential. The enzymatic extract produced by the fungus T. aurantiacus presented only saccharifying potential, releasing glucose monomers as the main hydrolysis product. Laboratory of Enzymology and Fermentation Processes Faculty of Biological and Environmental Sciences Federal University of Grande Dourados (FCBA/UFGD), Rodovia Dourados/Itahum, km 12 Faculty of Engineering Department of Phytotechnology Food Technology and Social Economy São Paulo State University (FEIS/UNESP), Avenida Brasil, No. 56 Laboratory of Fungal Ecology and Systematics Biosciences Institute Department of Biochemistry and Microbiology São Paulo State University (IB/UNESP), Avenida 24A, No. 1515 Laboratory of Bioengineering Faculty of Biological and Environmental Sciences Federal University of Grande Dourados (FCBA/UFGD), Rodovia Dourados/Itahum, km 12 Faculty of Engineering Department of Phytotechnology Food Technology and Social Economy São Paulo State University (FEIS/UNESP), Avenida Brasil, No. 56 Laboratory of Fungal Ecology and Systematics Biosciences Institute Department of Biochemistry and Microbiology São Paulo State University (IB/UNESP), Avenida 24A, No. 1515

International audience; La gestion pérenne des déchets issus de l'assainissement passe par des solutions adaptées au contexte des territoires. Elle doit notamment respecter les principes de proximité dans les circuits de collecte et traitement et permettre au mieux la valorisation des déchets. L'unité de traitement des matières de vidange de Nègrepelisse répond à ces impératifs avec une solution écologique qui offre plusieurs avantages : - sobriété énergétique dans les transports induits avec un site proche des déchets à éliminer, et dans la consommation énergétique de la filière extensive de traitement mise en ½uvre - valorisation énergétique vers une filière bois-énergie locale, - intégration paysagère avec une filière qui se fond dans le paysage environnant. - durabilité du système technique et agronomique. Le travail a consisté à suivre les performances de la filière dans son ensemble : traitements des effluents, distribution sur la parcelle et son homogénéité et valorisation des eaux usées traitées par la croissance des arbres sur une période de trois saisons d'irrigation. L'objectif était de valider la filière de traitement ainsi que de tester plusieurs modalités de conduite des irrigations afin de montrer que cette filière est très performante tant en terme de finalisation du traitement de l'effluent que de valorisation par la production de bois sans impacter le milieu.

International audience; This paper analyzes the determinants of international trade of wood products, considering three main groups: woodworking products, pulp and paper and wooden furniture. We extend the Heckscher-Ohlin-Vanek (HOV) framework in order to take into account the forest resource endowment as well as industrial performance factors. Empirical tests are based on data on European countries between 1995 and 2007. The HOV hypothesis is partially confirmed in that the forest resource endowment is a significant determinant for explaining differences in net trade of two products (pulp and paper and furniture) but not for woodworking products. In addition, empirical tests also show the limits of the HOV model for explaining international trade of wood products. Indeed, factors reflecting industrial performance of wood sectors, including total factor productivity and average labor cost, have a significant role in determining differences in net trade of wood products.

International audience; Polycross mating systems are widely used in forest tree breeding for genetic testing. Backward selection based on polycross testing assumes equal male reproductive success and true half-sib progeny. The main objectives of this study were, firstly, to investigate the departure from these assumptions in a maritime pine polycross trial and, secondly, to evaluate the consequences for heritability and breeding values estimations. A total of 984 offspring from 98 half-sib families was genotyped with single nucleotide polymorphism markers to recover the full pedigree. Paternity was assigned successfully for 89 % of the offspring at a 99 % confidence level. We thus concluded there was an 11 % pollen contamination rate, assuming contamination when no genotype from the polymix composition could be identified as a father. The paternal contribution to the offspring varied among the males, but the departure from half-sib assumption was moderate since the average genetic correlation within the family was 0.26. Heritability and breeding values for girth at breast height and stem sweep were estimated using individual-tree mixed models with either partial or full pedigree information. The results highlighted a minor bias in heritability estimation due to unknown paternity, as well as a high correlation for estimated breeding values between the partial and full pedigree models, suggesting that the genetic merit of the parental generation for backward selection was adequately predicted using the partial pedigree model. Finally, pedigree recovery was also discussed in a perspective of forward selection.

International audience; This work aims at studying the sodium periodate oxidation of 4-O-methylglucuronoxylans (MGX) in different experimental conditions for a control of the oxidation degree. A series of sodium periodate oxidation reactions were conducted at three NaIO4/xylose molar ratios: 0.05, 0.20 and 1.00. The effects of xylan molar mass, xylan concentration and reaction temperature on the reaction rate have been evaluated by UV/visible spectroscopy at 0.20 NaIO4/xylose ratio. No depolymerization is observed at 0.05 ratio while depolymerization occurs at 0.20 and is even complete at 1.00 NaIO4/xylose ratio. An increase of the reaction temperature - up to 80 degrees C - leads to an increase of the oxidation rate with no effect on the depolymerization. At high xylan concentrations, the oxidation rate increases but promotes chains aggregation.

International audience; Greater demand for wood material has converged with greater demand for biodiversity conservation to make balancing forest ecosystem services a key societal issue. Forest managers, owners, or policymakers need new approaches and methods to evaluate their ability to adapt to this dual objective. We analyze the ability of forest owners to define sustainable forest management options based on viability theory and a new flexibility index. This new indicator gauges the adaptive capacity of forest owners based on the number of sustainable actions available to them at a given time. Here we study a public forest owner who regulates harvest intensity and frequency in order to meet demand for timber wood at forest scale and to meet a biodiversity recommendation via a minimum permanently maintained volume of deadwood per hectare at stand scale. Dynamical systems theory was used to model uneven-aged forest dynamics-including deadwood dynamics-and the dynamics of timber wood demand and tree removals. Uneven-aged silver fir forest management in the "Quatre Montagnes region" (Vercors, France) is used as an illustrative example. The results explain situations where a joint increase in wood production and deadwood retention does not reduce the flexibility index more than increasing either one dimension alone, thus opening up ecological intensification options. To conclude, we discuss the value of the new flexibility index for addressing environmental management and ecological intensification issues.

BIOVERT+VBI:CPI:FRA; Cationizations of galactomannan- and xylan-type hemicelluloses were performed in a solid state, with 2,3-epoxypropyltrimethylammonium chloride (ETA) as the cationic reagent under alkaline conditions. By this method, the reaction efficiency was significantly increased for all hemicellulose types, up to 90% in the case of xylan. The consumption of reagents was reduced by a factor of ten when compared to the reaction in liquid phase, while comparable values of the degree of substitution (DS) were obtained. By reducing the number of purification steps, the consumption of solvents was limited, and high mass yields were preserved. By all aspects, this method constitutes an economical and environmental gain for the cationization reaction of hemicelluloses. Native hemicelluloses and their cationic derivatives were tested as additives to the pulp slurry in order to increase the dry strength of the paper formed. The cationization of hemicelluloses had a beneficial effect on the mechanical properties of paper, with a supplementary gain of properties compared to the unmodified polysaccharides. Cationic derivatives of a DS 0.3 gave the best results for both polysaccharides, with the galactomannan-type being more efficient than the xylan-type with a 90% increase of the burst index.

International audience; In this work, the effects of moisture content variations produced by oscillating drying conditions have been studied by means of non-symmetrical drying (flying wood) and loaded drying (3-point bending test). The oscillating conditions are intended to produce a mechano-sorptive creep that is able to reduce drying stresses. However, our experimental data seem to prove that the activation of the mechano-sorptive creep by oscillations of the moisture content is very limited. Besides, the simulations showed that noisy conditions due to the kiln regulation already activate the mechano-sorptive creep, even for non-oscillating conditions, and could confuse the results. Contrary to the experimental observations, the implementation of classical mechano-sorptive models in the drying simulation model is far too optimistic, which means that these models are not suitable when the material is submitted to numerous oscillations.

International audience; Poplar coppice plantations for biomass production can be conducted under either short rotation coppice (SRC) or short rotation forestry (SRF) systems, depending on planting density and rotation length. It is likely that differences in planting density affect tree physiology through competition for resource acquisition, including light, water and nutrients. In this paper, we hypothesized that the effects of planting density on growth and water-use efficiency (assessed through bulk leaf carbon isotope discrimination, Delta C-13) in poplar depend on site characteristics in terms of soil fertility and water availability. To test this hypothesis, 56 Populus deltoides x P. nigra genotypes were planted under both SRC and SRF and replicated at two sites differing for pedoclimatic conditions. At the most favorable site for growth, trees grown at the higher density (SRC) displayed higher stem height, lower stem circumference, higher specific leaf area, higher mass-based leaf nitrogen contents and higher Delta C-13, indicating that increased tree density mainly accentuated competition for light. Under less favorable conditions, trees grown under SRC still displayed lower stem circumference, higher specific leaf area and higher mass-based leaf nitrogen contents. However, stem height remained unaffected by increasing planting density while Delta C-13 was lower, likely because of increased competition for water availability. Genotypic rankings across planting densities were overall conserved while they were significantly modified across sites, suggesting that rankings for genotypic performances were much less affected by planting density than by site. Realized growth measured after 2 years (height and circumference) was weakly correlated with Delta C-13, but a negative relationship between Delta C-13 and growing season leaf increment rate was observed in most cases. The absence of trade-off between growth and water-use efficiency combined with the large genotypic variations observed for these traits confirms the potential for selecting genotypes with high water-use efficiency without counter-selecting on biomass production in P. deltoides x P. nigra.

1 Bigand, Virginie Pinel, Catherine Perez, Denilson Da Silva Rataboul, Franck Huber, Patrick Petit-Conil, Michel; In this study, the cationisation of galactomannan and xylan hemicellulose types was investigated with 2,3-epoxypropyltrimethylammonium chloride (ETA) as reagent, under alkaline conditions. The degree of substitution was accurately determined by H-1 NMR spectroscopy after hydrolysis in a DCl/D2O mixture and confirmed by elemental analyses. The influence of reactional parameters on yield and DS was studied systematically and the reactivity of both polysaccharides was compared. DS values from 0.1 to 1.3 were obtained by varying reactional parameters, the most influential being the hemicellulose concentration and the epoxide amount. The corresponding mass yields varied from 40 to 80% of recovered hemicelluloses and were strongly correlated to DS values. The cationisation of xylan was studied more particularly with a D-optimal experimental design in order to identify interactions between parameters. The optimization of reactional parameters as a function of a desired DS allowed obtaining a maximal grafting rate of 48% with a DS value of 1.3 and 64% of mass yield. (C) 2011 Elsevier Ltd. All rights reserved.

International audience; Mixed interior wood panel tannin adhesive formulations were developed in which lignin is in considerable proportion, 50%, of the wood panel binder and in which no "fortification" with synthetic resins, such as isocyanates and phenol-formaldehyde resins as used in the past, was necessary to obtain results satisfying relevant standards. A low molecular mass lignin obtained industrially by formic acid/acetic acid pulping of wheat straw was used. Environment-friendly, non-toxic polymeric materials of natural origin constitute up to 94% of the total panel binder. The wood panel itself is constituted of 99.5% natural materials, the 0.5% balance being composed of glyoxal, a non-toxic and non-volatile aldehyde, and of hexamine already accepted as a non-formaldehyde-yielding compound when in presence of condensed tannin. Both particleboard and two types of plywood were shown to pass the relevant interior standards with such adhesive formulations. Moreover, the much cheaper non-purified organosolv lignin showed the same level of results as the more expensive purified type.