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Camargo E.L.O.,University of Campinas | Nascimento L.C.,University of Campinas | Soler M.,CNRS Plant Research Laboratory | Salazar M.M.,University of Campinas | And 11 more authors.
BMC Plant Biology | Year: 2014

Nitrogen (N) is a main nutrient required for tree growth and biomass accumulation. In this study, we analyzed the effects of contrasting nitrogen fertilization treatments on the phenotypes of fast growing Eucalyptus hybrids (E. urophylla x E. grandis) with a special focus on xylem secondary cell walls and global gene expression patterns. Results: Histological observations of the xylem secondary cell walls further confirmed by chemical analyses showed that lignin was reduced by luxuriant fertilization, whereas a consistent lignin deposition was observed in trees grown in N-limiting conditions. Also, the syringyl/guaiacyl (S/G) ratio was significantly lower in luxuriant nitrogen samples. Deep sequencing RNAseq analyses allowed us to identify a high number of differentially expressed genes (1,469) between contrasting N treatments. This number is dramatically higher than those obtained in similar studies performed in poplar but using microarrays. Remarkably, all the genes involved the general phenylpropanoid metabolism and lignin pathway were found to be down-regulated in response to high N availability. These findings further confirmed by RT-qPCR are in agreement with the reduced amount of lignin in xylem secondary cell walls of these plants. Conclusions: This work enabled us to identify, at the whole genome level, xylem genes differentially regulated by N availability, some of which are involved in the environmental control of xylogenesis. It further illustrates that N fertilization can be used to alter the quantity and quality of lignocellulosic biomass in Eucalyptus, offering exciting prospects for the pulp and paper industry and for the use of short coppices plantations to produce second generation biofuels. © 2014 Camargo et al.; licensee BioMed Central Ltd.


Salazar M.M.,Genomic Expression | Salazar M.M.,Senai Innovation Institute for Biomass | Grandis A.,University of Sao Paulo | Pattathil S.,University of Georgia | And 11 more authors.
Bioenergy Research | Year: 2016

The architecture, composition, and chemical properties of wood cell walls have a direct influence on the process that occurs prior to fermentation in second-generation biofuel production. The understanding of the construction patterns of cell wall types is the key to the new era of second-generation biofuels. Eucalyptus species are great candidates for this purpose since these species are among the fastest growing hardwood trees in the world and they have been improved for biomass production. We applied the glycome profiling and other combined techniques to study xylem cell walls of three economically important species (Eucalyptus globulus, Eucalyptus grandis, and Eucalyptus urophylla). Glycome profiling analyses revealed that species differ in the same key aspects of cell wall polymer linkages, with E. globulus and E. urophylla presenting contrasting phenotypes, and E. grandis with intermediate characteristics. E. urophylla is known for high recalcitrance, that is probably determined by the strong associations between lignin and cell wall polymers, and also lignin content. On the other hand, E. globulus cell wall polymers are loosely linked, so its cell wall can be easily deconstructed. We have shown in this work that the composition of cell walls differs in quantity and quality among the Eucalyptus species and such variations in composition influence the process of lignocellulosic feedstock assessment. However, the greatest influence relies on the amount and type of associations between cell wall polymers. A high yield of cellulose, from any biomass source, directly depends on the cell wall architecture. © 2016 Springer Science+Business Media New York


Pizzo B.,CNR Tree and Timber Institute | Pecoraro E.,CNR Tree and Timber Institute | Alves A.,Tropical Research Institute of Portugal IICT | Alves A.,University of Lisbon | And 3 more authors.
Talanta | Year: 2015

This paper reports on the assessment of lignin and holocellulose by means of ATR-FTIR analysis and multivariate PLS regression. The analysis was conducted on 59 samples coming from different excavations where wood had been preserved in waterlogged conditions. A range of results from different wood species (Alnus sp.p., Cupressus sempervirens, Larix decidua, Picea abies, Pinus sp.p., Quercus sp.p., Ulmus sp.p.), states of preservation, waterlogged environments, and burial times are presented. A calibration model was selected after comparing different reference data (samples extracted and not-extracted, and ash-rich and ash-free bases of calculation for the calibration values), and two different post-acquisition spectroscopic manipulations (both in terms of normalisation procedures and of spectral ranges used for the calibration). Results showed that the best models were different depending on which considered component (lignin or holocellulose) was measured and to which data set (softwood or hardwood) the samples belonged. It is shown that the predictive ability of the models is affected by high ash content (too contaminated samples had to be excluded in order to attain good results, because of excessive overlapping of bands related to the inorganic fraction) but not by the preliminary extraction of sample. Furthermore, the stability of best models is also demonstrated and a procedure of external validation carried out on an external set of samples confirmed the general validity of the identified models. © 2014 Elsevier B.V.


Pecoraro E.,CNR Tree and Timber Institute | Pizzo B.,CNR Tree and Timber Institute | Alves A.,Tropical Research Institute of Portugal IICT | Alves A.,University of Lisbon | And 3 more authors.
Microchemical Journal | Year: 2015

Present work describes the application of NIR spectroscopy coupled with Partial least square (PLS) regression to estimate the residual chemical composition (in terms of holocellulose and lignin) of wood decayed by attack of biotic agents (such as bacteria) when preserved for a long-time in waterlogged conditions. The evaluations allowed assessing how various parameters may influence the predictive ability of calibration models. These parameters include: pre-processing manipulations (first and second derivatives curves, both normalized and not, were compared with baseline corrected spectra), the ranges used for model calibration, the preliminary conditioning of the samples (meals conditioned at both 22. °C/50% r.h. and 60. °C), and the way to take account of the presence of inorganic fillers permeating wood. To such aim, 59 samples from different excavations were considered, with samples belonging to several hardwoods and softwoods (Alnus sp.p., Cupressus sempervirens, Larix decidua, Picea abies, Pinus sp.p., Quercus sp.p., Ulmus sp.p.), and to different states of preservation and burial environments. Values used for calibration were obtained by conventional wet analyses. Results showed that NIR spectroscopy coupled with PLS multivariate analysis could be used to reliably assess the residual chemical composition of waterlogged decayed wood provided that the calibration range is carefully selected and that original data are suitably pre-processed. However, the best models were different for the two considered components (lignin and holocellulose) and depending on which data set (softwoods or hardwoods) the samples belonged. Finally, it was also shown that the models predictive ability is affected by high ash content (too contaminated samples had to be excluded in order to attain good results). © 2015 Elsevier B.V.


Alves A.M.M.,Tropical Research Institute of Portugal IICT | Alves A.M.M.,University of Lisbon | Simoes R.F.S.,Tropical Research Institute of Portugal IICT | Santos C.A.,Tropical Research Institute of Portugal IICT | And 3 more authors.
Journal of Near Infrared Spectroscopy | Year: 2012

Wood extractives, the non-cell wall components that can be removed by solvents, can play an important role in the protection of the living tree as well as derived wood products. On the other hand they can be detrimental for pulp and paper, paint and varnish films and adhesives. The objective of this work was to develop near infrared-based partial least squares regression models for the prediction of wood extractives. The developed models are well suited for screening of the ethanol and total extractives content of Eucalyptus globulus wood. The models for the prediction of ethanol extractives with residual prediction deviations above 5 are also suited for quality control. It is shown that samples with high extractives content always have a more intense OH combination band than the samples with low extractives content and that near infrared can be used for a rough estimation of the relative performance of the reference methods. © 2012 IM Publications LLP.


Machado J.S.,National Laboratory for Civil Engineering | Louzada J.L.,University of Trás os Montes e Alto Douro | Santos A.J.A.,University of Lisbon | Santos A.J.A.,University of Beira Interior | And 7 more authors.
Materials and Design | Year: 2014

The variation of wood density and mechanical properties with site, tree and within tree (longitudinal and radial) were studied for blackwood (. Acacia melanoxylon R. Br.) grown in four sites in Portugal. Twenty trees were randomly selected (40. cm. dbh class, 33-51. years of age), sampled at three stem height levels (5%, 35% and 65% of tree height) and three radial positions (10%, 50% and 90% of radius). They were further tested for air-dry density at 12% moisture content, bending strength (MOR), modulus of elasticity (MOE) and compression strength parallel to grain (CS), using ISO standards.The overall mean properties of blackwood were: 654kgm-3 density, 139Nmm-2 MOR, 141×102Nmm-2 MOE and 61Nmm-2 CS. Site was not a significant source of variation for all wood properties. The variation between individual trees was the most important. Within the tree, the radial variation was highly significant for all traits, while the longitudinal variation was only significant for density. The correlation of density with the mechanical properties was moderate.Blackwood showed potential for being an alternative species to supply the industry with valuable hardwood timber. The significant differences found between the trees demonstrate the possibility of selection and improvement for increased wood quality. © 2013 Elsevier Ltd.


Santos A.J.A.,Tropical Research Institute of Portugal IICT | Santos A.J.A.,University of Lisbon | Alves A.M.M.,Tropical Research Institute of Portugal IICT | Alves A.M.M.,University of Lisbon | And 4 more authors.
Journal of Near Infrared Spectroscopy | Year: 2012

Wood basic density is one of the most important wood quality properties and one of the simplest to assess but it is too time consuming to be really useful for the screening of populations or for improvement programmes where large numbers of samples need to be assessed. Although the usefulness of near infrared (NIR) spectroscopy to assess wood properties, including wood density, is well established only a few of the published models are suitable for screening. The NIR-based partial least squares regression models obtained in this study can be used for screening the basic density of the Portuguese blackwood [Acacia melanoxylon (R. Br.)] population with standard errors of cross-validation of only 11 kg m -3 and values for the residual prediction deviation well above the 2.5 limit. It was also concluded that at least 45 samples for calibration and a further 16 samples for validation are necessary to obtain acceptable models for screening. Even using a very small number of spectra per disc, accurate estimates of wood basic density were obtained. © 2012 IM Publications LLP.


Santos A.J.A.,University of Lisbon | Santos A.J.A.,University of Beira Interior | Santos A.J.A.,Tropical Research Institute of Portugal IICT | Anjos O.,University of Lisbon | And 4 more authors.
BioResources | Year: 2014

A total of 120 Acacia melanoxylon R. Br. (Australian blackwood) stem discs, belonging to 20 trees from four sites in Portugal, were used in this study. The samples were kraft pulped under standard identical conditions targeted to a Kappa number of 15. A Near Infrared (NIR) partial least squares regression (PLSR) model was developed for the Kappa number prediction using 75 pulp samples with a narrow Kappa number variation range of 10 to 17. Very good correlations between NIR spectra of A. melanoxylon pulps and Kappa numbers were obtained. Besides the raw spectra, also pre-processed spectra with ten methods were used for PLS analysis (cross validation with 48 samples), and a test set validation was made with 27 samples. The first derivative spectra in the wavenumber range from 6110 to 5440 cm-1 yielded the best model with a root mean square error of prediction of 0.4 units of Kappa number, a coefficient of determination of 92.1%, and two PLS components, with the ratios of performance to deviation (RPD) of 3.6 and zero outliers. The obtained NIR-PLSR model for Kappa number determination is sufficiently accurate to be used in screening programs and in quality control.


Stackpole D.J.,University of Tasmania | Stackpole D.J.,Scion Research | Vaillancourt R.E.,University of Tasmania | Alves A.,Tropical Research Institute of Portugal IICT | And 2 more authors.
G3: Genes, Genomes, Genetics | Year: 2011

Despite the ecological and economic importance of lignin and other wood chemical components, there are few studies of the natural genetic variation that exists within plant species and its adaptive significance. We used models developed from near infra-red spectroscopy to study natural genetic variation in lignin content and monomer composition (syringyl-to-guaiacyl ratio [S/G]) as well as cellulose and extractives content, using a 16-year-old field trial of an Australian tree species, Eucalyptus globulus. We sampled 2163 progenies of 467 native trees from throughout the native geographic range of the species. The narrow-sense heritability of wood chemical traits (0.25-0.44) was higher than that of growth (0.15), but less than wood density (0.51). All wood chemical traits exhibited significant broad-scale genetic differentiation (QST = 0.34-0.43) across the species range. This differentiation exceeded that detected with putatively neutral microsatellite markers (FST = 0.09), arguing that diversifying selection has shaped population differentiation in wood chemistry. There were significant genetic correlations among these wood chemical traits at the population and additive genetic levels. However, population differentiation in the S/G ratio of lignin in particular was positively correlated with latitude (R2 = 76%), which may be driven by either adaptation to climate or associated biotic factors. © 2011 Stackpole et al.


Lepikson-Neto J.,University of Campinas | Alves A.,Tropical Research Institute of Portugal IICT | Simoes R.,Tropical Research Institute of Portugal IICT | Deckmann A.C.,University of Campinas | And 6 more authors.
BioResources | Year: 2013

The Eucalyptus genus plays an important role in the worldwide forest industry, with highly productive plantations supplying high-quality raw material for pulp and paper, wood, and biomass that would otherwise come from native forests. Lignin and extractives are important components for wood structure and protection but they are disruptive elements with respect to some industrial processes involving paper, pulp, and biomass production. This work evaluated effects of supplementation of flavonoids on the wood composition of Eucalyptus grandis x Eucalyptus urophylla (E. urograndis), a commercial hybrid. The wood samples were analyzed for extractives and lignin contents by wet chemical analysis, and the composition of lignin monomers and the carbohydrate hexosan/pentosan ratio were determined by analytical pyrolysis. The results showed that supplementation with the flavonoids naringenin and naringenin-chalcone led to an overall reduction of the extractive content and altered the monomeric composition of lignins towards a higher syringyl content. Thus, the treatment of Eucalyptus with flavonoids results in the improvement of wood quality for technological purposes.

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