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PubMed2004

Two possible pathways for the release of arsenic during pyrolysis of chromated copper arsenate (CCA)-treated wood.

The behavior of arsenic during pyrolysis at temperatures between 135 and 500 degrees C has been widely studied. We examined the release of arsenic during the pyrolysis of chromated copper arsenate (CCA)-treated wood, and here we propose two models for the volatilization of arsenic: (a) a reacted arsenic compound, chromium arsenate, in CCA-treated wood was initially decomposed to arsenic pentoxide, which then appeared to be released at around 400-500 degrees C as a form of arsenic trioxide; and (b) an unreacted arsenic compound, arsenic pentoxide, in CCA-treated wood was released at much lower temperatures than reacted arsenic compound, as a form of arsenic trioxide. In order to restrain the release of arsenic during pyrolysis, it is possible to pyrolyze CCA-treated wood carefully at temperatures around 300-350 degrees C only if the wood contains little unreacted arsenic compound. Under these conditions, almost all toxic elements remain in the pyrolysis residue, and a weight reduction of the wood of approximately 50% can be obtained. On the other hand, the release of arsenic can be achieved easily using an unreacted arsenic compound under the same pyrolysis conditions. However, in the present study it was difficult to determine the accurate release point of arsenic in both cases due to the level of experimental uncertainty.

Arsenic↗
PubMed2004

A UV resonance Raman (UVRR) spectroscopic study on the extractable compounds of Scots pine (Pinus sylvestris) wood. Part I: lipophilic compounds.

The wood resin in Scots pine (Pinus sylvestris) stemwood and branch wood were studied using UV resonance Raman (UVRR) spectroscopy. UVRR spectra of the sapwood and heartwood hexane extracts, solid wood samples and model compounds (six resin acids, three fatty acids, a fatty acid ester, sitosterol and sitosterol acetate) were collected using excitation wavelengths of 229, 244 and 257 nm. In addition, visible Raman spectra of the fatty and resin acids were recorded. Resin compositions of heartwood and sapwood hexane extracts were determined using gas chromatography. Raman signals of both conjugated and isolated double bonds of all the model compounds were resonance enhanced by UV excitation. The oleophilic structures showed strong bands in the region of 1660-1630 cm(-1). Distinct structures were enhanced depending on the excitation wavelength. The UVRR spectra of the hexane extracts showed characteristic bands for resin and fatty acids. It was possible to identify certain resin acids from the spectra. UV Raman spectra collected from the solid wood samples containing wood resin showed a band at approximately 1650 cm(-1) due to unsaturated resin components. The Raman signals from extractives in the resin rich branch wood sample gave even more strongly enhanced signals than the aromatic lignin.

Abietanes↗
PubMed2004

Elemental analyses of pine bark and wood in an environmental study.

Bark and wood samples were taken from the same individuals of Scots pine (Pinus sylvestris L.) from a polluted area close to a Cu-Ni smelter in Harjavalta and from some relatively unpolluted areas in western Finland. The samples were analysed by thick-target particle induced X-ray emission (PIXE) after preconcentration by dry ashing at 550 degrees C. The elemental contents of pine bark and wood were compared to study the impact of heavy metal pollution on pine trees. By comparison of the elemental contents in ashes of bark and wood, a normalisation was obtained. For the relatively clean areas, the ratios of the concentration in bark ash to the concentration in wood ash for different elements were close to 1. This means that the ashes of Scots Pine wood and bark have quite similar elemental composition. For the samples from the polluted area the mean concentration ratios for some heavy metals were elevated (13-28), reflecting the effect of direct atmospheric contamination. The metal contents in the ashes of pine bark and wood were also compared to recommendations for ashes to be recycled back to the forest environment. Bark from areas close to emission sources of heavy metal pollution should be considered with caution if aiming at recycling the ash. Burning of bark fuel of pine grown within 6 km of the Cu-Ni smelter is shown to generate ashes with high levels of Cu, Ni as well as Cd, As and Pb.

Environmental Monitoring↗
PubMed2006

Electrodialytic remediation of CCA-treated waste wood in a 2 m(3) pilot plant.

Waste wood that has been treated with chromated-copper-arsenate (CCA) poses a potential environmental problem due to the content of copper, chromium and arsenic. A pilot plant for electrodialytic remediation of up to 2 m(3) wood has been designed and tested and the results are presented here. Several process parameters were investigated, and it was found that the use of collecting units and soaking of the wood prior to the electrodialytic process had a positive influence on the remediation process. There was a tendency towards higher removal of CCA from wood chips <2 cm, compared to larger wood size fractions. The best remediation efficiency was obtained in an experiment with an electrode distance of 60 cm, and 100 kg wood chips. In this experiment 87% copper, 81% chromium and >95% arsenic were removed. One other experiment was also analysed for arsenic. In this experiment the distance between the working electrodes was 1.5 m and here 95% As was removed. The results showed that arsenic may be the easiest removable of the copper, chromium and arsenic investigated here. This is very encouraging since arsenic is the CCA components of most environmental concern.

Arsenates↗
PubMed2006

A pilot study of children's exposure to CCA-treated wood from playground equipment.

Arsenic from chromated copper arsenate (CCA)-treated wood, widely used in playgrounds and other outdoor equipment, can persist as surface residues on wood. This raises concerns about possible health risks associated with children playing on CCA-treated playgrounds. In a Pilot Study, 11 children (13-71 months) in homes with and without CCA-treated playgrounds were evaluated with post-exposure hand rinses and urine for total arsenic. Samples of wood, soil, and mulch, as well as synthetic wipes, were sampled for total arsenic. In non-CCA-treated playgrounds vs. CCA-treated playgrounds, respectively, wood arsenic was <2.0 mg/kg vs. mean arsenic 2370 mg/kg (range 1440-3270 mg/kg); soil arsenic was <3.0 mg/kg vs. mean arsenic of 19 mg/kg (range 4.0-42 mg/kg); mulch arsenic at one non-CCA-treated playground was 0.4 mg/kg vs. two CCA-treated playgrounds of 0.6 and 69 mg/kg. The arsenic removed using a synthetic wipe at non-CCA-treated playgrounds was <0.5 microg, while mean arsenic from CCA-treated wood was 117 microg (range 1.0-313). The arsenic mass from hand rinses for children who played at non-CCA-treated playgrounds was <0.2 microg, while mean arsenic mass was 0.6 microg (range <0.2-1.9) at CCA-treated playgrounds. Mean urinary total arsenic levels were 13.6 pg/ml (range 7.2-23.1 pg/ml) for all children evaluated, but there was no association between access to CCA-playgrounds and urinary arsenic levels. Arsenic speciation was not performed. This preliminary Pilot Study of CCA-treated wood playgrounds observed dislodgeable arsenic on 11 children's hands after brief periods of play exposure. Future efforts should increase the number of children and the play exposure periods, and incorporate speciation in order to discriminate between various sources of arsenic.

Arsenates↗
PubMed2004

Evaluating phenanthrene sorption on various wood chars.

A certain amount of wood char or soot in a soil or sediment sample may cause the sorption of organic compounds to deviate significantly from the linear partitioning commonly observed with soil organic matter (SOM). Laboratory produced and field wood chars have been obtained and analyzed for their sorption isotherms of a model solute (phenanthrene) from water solution. The uptake capacities and nonlinear sorption effects with the laboratory wood chars are similar to those with the field wood chars. For phenanthrene aqueous concentrations of 1 microg l(-1), the organic carbon-normalized sorption coefficients (log K(oc)) ranging from 5.0 to 6.4 for field chars and 5.4-7.3 for laboratory wood chars, which is consistent with literature values (5.6-7.1). Data with artificial chars suggest that the variation in sorption potential can be attributed to heating temperature and starting material, and both the quantity and heterogeneity of surface-area impacts the sorption capacity. These results thus help to corroborate and explain the range of logK(oc) values reported in previous research for aquifer materials containing wood chars.

Adsorption↗
PubMed2003

Health effects on nearby residents of a wood treatment plant.

OBJECTIVES: The aim of the study was to evaluate the health status of nearby residents of a wood treatment plant who had sustained prolonged low-level environmental exposure to wood processing waste chemicals. METHODS: A population of 1269 exposed residents who were plaintiffs or potential plaintiffs in a lawsuit against the wood treatment plant were evaluated by questionnaire for a health history and symptoms. A representative sample of 214 exposed subjects was included in the analysis. One hundred thirty-nine controls were selected from 479 unexposed volunteers and matched to the exposed subjects as closely as possible by gender and age. Subjects and controls completed additional questionnaires and were evaluated by a physician for medical history and physical examination, blood and urine testing, neurophysiological and neuropsychological studies, and respiratory testing. Environmental sampling for wood processing waste chemicals was carried out on soil and drainage ditch sediment in the exposed neighborhood. RESULTS: The exposed subjects had significantly more cancer, respiratory, skin, and neurological health problems than the controls. The subjective responses on questionnaires and by physician histories revealed that the residents had a significantly greater prevalence of mucous membrane irritation, and skin and neurological symptoms, as well as cancer. (Exposed versus unexposed, cancer 10.0% versus 2.08%, bronchitis 17.8% versus 5.8%, and asthma by history 40.5% versus 11.0%) There were significantly more neurophysiologic abnormalities in adults of reaction time, trails A and B, and visual field defects. CONCLUSIONS: Adverse health effects were significantly more prevalent in long-term residents near a wood treatment plant than in controls. The results of this study suggest that plant emissions from wood treatment facilities should be reduced.

Adolescent↗
PubMed2001

Dietary vegetable oil and wood derived plant stanol esters reduce atherosclerotic lesion size and severity in apoE*3-Leiden transgenic mice.

The hypolipidemic and anti-atherosclerotic effects of vegetable oil- and wood-based dietary plant stanol esters were compared in female apoE*3-Leiden transgenic mice at relevant plasma cholesterol levels. The plant stanol esters derived from vegetable oil (sitostanol 65.7%, campestanol 30.1%) had different contents of sitostanol and campestanol than the plant stanol esters derived from wood (sitostanol 87.6%, campestanol 9.5%) or from a mixture of vegetable oil and wood (sitostanol 73.0%, campestanol 24.7%). The mice (10 per group) received for 38 weeks a control diet or diets containing 1.0% (w/w) plant stanol esters derived from either vegetable oil, wood or a mixture of both. Vegetable oil (-46%), wood (-42%) and vegetable oil/wood (-51%) plant stanol esters decreased the plasma cholesterol levels (P<0.0001) by reducing the cholesterol content in plasma very low density-, intermediate density- and to a lesser extent in low density-lipoprotein. Plant stanol ester feeding did not change plasma triglyceride levels. Dietary plant stanol esters reduced the atherosclerotic lesion area by 91+/-13% (vegetable oil), 97+/-4% (wood) and 78+/-34% (vegetable oil/wood) (P<0.0001) and the severity from regular intimal fatty streaks/mild plaques (on average type 2--3 lesions) in controls to individual intimal foam cells (<type 1 lesions) in the treatment groups (P<0.0001). Plant stanol esters had no effect on adherence of monocytes to the vessel wall. Feeding of plant stanol esters dramatically reduced, independent of its sources, the extent and severity of atherosclerotic lesions, by decreasing VLDL-, IDL- and to a lesser extent LDL-cholesterol in apoE*3-Leiden transgenic mice.

Animals↗
PubMed2001

Airway hyperresponsiveness to bronchoconstrictor challenge after wood smoke exposure in guinea pigs.

Prior airway exposure to wood smoke induces an increase in airway responsiveness to subsequent smoke inhalation in guinea pigs (Life Sci. 63: 1513, 1998; 66: 971, 2000). To further characterize this airway hyperreactivity, we investigated and compared the airway responsiveness to bronchoconstrictor challenge before and 30 min after sham air exposure or wood smoke exposure in anesthetized and artificially ventilated guinea pigs. Various doses of substance P (0.8-6.4 microg/kg), capsaicin (0.2-3.2 microg/kg), prostaglandin F2alpha (30-3000 microg/kg), histamine (1-8 microg/kg), or acetylcholine (5-20 microg/kg) were intravenously injected at 2-min intervals in successively increasing doses to obtain the dose required to provoke a 200% increase in baseline total lung resistance (ED200). Wood smoke exposure significantly lowered the ED200 of substance P, capsaicin, and prostaglandin F2alpha whereas sham air exposure failed to do so. Furthermore, wood smoke exposure did not significantly alter the ED200 of histamine or acetylcholine. Pretreatment with phosphoramidon (2 mg/kg), an inhibitor of the neutral endopeptidase (the major degradation enzyme of substance P), before smoke exposure did not significantly affect the smoke-induced reduction in ED200 of substance P. Sectioning both cervical vagi before smoke exposure did not significantly alter the smoke-induced reduction in ED200 of capsaicin or prostaglandin F2alpha. These results suggest that airway exposure to wood smoke acutely produces airway hyperresponsiveness to substance P, capsaicin, and prostaglandin F2alpha, but not to histamine or acetylcholine. Since the combination of phosphoramidon and wood smoke exposure did not result in an additive potentiation of smoke-induced airway hyperresponsiveness to substance P, it is suggested that an inhibition of the degradation enzyme of substance P may contribute to this increase in airway reactivity. Furthermore, vagally-mediated bronchoconstriction does not play a vital role in enhanced airway responsiveness to capsaicin or prostaglandin F2alpha.

Acetylcholine↗
PubMed1996

Occupational exposure to metal or wood dust and aetiology of cryptogenic fibrosing alveolitis.

BACKGROUND: We have previously suggested that cryptogenic fibrosing alveolitis (CFA) may be caused by occupational exposures, particularly to metal or wood dust. We have specifically investigated this hypothesis in a case-control study of patients with CFA. METHODS: We obtained lifetime occupational histories by postal questionnaire from 218 patients with CFA and 569 controls matched for age, sex, and community, living in the Trent region of the UK. Information was subsequently verified by telephone interview in 165 cases and 408 controls. Serum IgE, rheumatoid factor, and antinuclear antibodies and skin sensitivity to common allergens were measured in cases and in one matched control for each. FINDINGS: The relative risk of CFA, after adjustment for smoking, was significantly increased in relation to questionnaire-reported exposure to metal dust (odds ratio 1.68 [95% CI 1.07-2.65], p = 0.024) or to wood dust (1.71 [1.01-2.92], p = 0.048). Similar results were obtained with the telephone interview data. Significant exposure-response effects were found for both metal-dust and wood-dust exposure. CFA was also associated with the presence of rheumatoid factor or antinuclear antibodies, but not with positive allergen skin tests or raised IgE concentrations. There was no evidence of interaction between the effects of rheumatoid factor, antinuclear antibodies, positive skin allergen tests, or IgE concentrations and exposure to metal or wood dust. The combined aetiological fraction attributable to exposure to metal or wood dust was of the order of 20%. INTERPRETATION: Occupational exposures to metal or wood dust are independent risk factors for CFA. Avoidance or limitation of these exposures may provide an opportunity to prevent the disease.

Autoantibodies↗
PubMed2003

Effects of bacterial treatments on wood extractives.

Bacterial strains were isolated from spruce wood chips and their ability to reduce the content of wood extractives was studied. Strains were screened by cultivation on liquid media containing wood extractives as the major nutrient. Some bacterial species could decrease remarkably the amount of extractives in the liquid media and reduced the amount of triglycerides, steryl esters and total extractives by 100, 20 and 39%, respectively. Spruce wood chips were treated in controlled conditions with selected bacteria to test their effects on the chips. All the bacteria grew well on wood chips. The effect of bacterial metabolism on wood extractives was significant. Bacterial treatments reduced the amount of lipophilic extractives by 16-38% in 1 week of treatment and up to 67% in 2 weeks. The most efficient strain removed 90, 66 and 50% of triglycerides, steryl esters and resin acids, respectively, in 2 weeks. These results indicate that bacteria may be promising agents for the removal of extractives for improved pulping and papermaking processes.

Bacteria↗
PubMed2003

Rice straw-wood particle composite for sound absorbing wooden construction materials.

In this study, rice straw-wood particle composite boards were manufactured as insulation boards using the method used in the wood-based panel industry. The raw material, rice straw, was chosen because of its availability. The manufacturing parameters were: a specific gravity of 0.4, 0.6, and 0.8, and a rice straw content (10/90, 20/80, and 30/70 weight of rice straw/wood particle) of 10, 20, and 30 wt.%. A commercial urea-formaldehyde adhesive was used as the composite binder, to achieve 140-290 psi of bending modulus of rupture (MOR) with 0.4 specific gravity, 700-900 psi of bending MOR with 0.6 specific gravity, and 1400-2900 psi of bending MOR with a 0.8 specific gravity. All of the composite boards were superior to insulation board in strength. Width and length of the rice straw particle did not affect the bending MOR. The composite boards made from a random cutting of rice straw and wood particles were the best and recommended for manufacturing processes. Sound absorption coefficients of the 0.4 and 0.6 specific gravity boards were higher than the other wood-based materials. The recommended properties of the rice straw-wood particle composite boards are described, to absorb noises, preserve the temperature of indoor living spaces, and to be able to partially or completely substitute for wood particleboard and insulation board in wooden constructions.

Absorption↗
PubMed2001

Evolution of ellagitannins in Spanish, French, and American oak woods during natural seasoning and toasting.

The evolution of tannins in Spanish oak heartwood of Quercus robur L., Quercus petraea Liebl.,Quercus pyrenaica Wild., and Quercus faginea Lam. was studied in relation to the processing of wood in barrel cooperage. Their evolution was compared with that of French oak of Q. robur (Limousin, France) and Q. petraea (Allier, France) and American oak of Quercus alba L. (Missouri), which are habitually used in cooperage. Two stages of process were researched: the seasoning of woods during 3 years in natural conditions and toasting. Total phenol and total ellagitannin contents and optical density at 420 nm of wood extracts were determined. The ellagitannins roburins A-E, grandinin, vescalagin, and castalagin were identified and quantified by HPLC, and the molecular weight distribution of ellagitannins was calculated by GPC. During the seasoning process the different ellagitannin concentrations decreased according to the duration of this process and in the same way as those in French and American woods. The toasting process also had an important influence on the ellagitannin composition of wood. Roburins A-E, grandinin, vescalagin, and castalagin decreased during this process in the Spanish wood species, in the same proportion as in the French and American ones. Also, the seasoning and toasting processes lead to qualitative variations in the structure of ellagitannins, especially in the molecular weight distribution, as was evidenced by GPC analysis of their acetylated derivatives.

Chromatography, High Pressure Liquid↗
PubMed2002

Influence of oak wood on the aromatic composition and quality of wines with different tannin contents.

The aromatic compounds associated with aging in wood have been studied in Monastrell wines containing different quantities of tannin. Analyses were carried out before and after a six month period in wooden barrels (225 L) of American and French (Allier) medium-toasted oak. Three classes of wine were made: one from a free-run must; one to which enological tannin was added; and one to which was added the wine obtained by pressing the grape pomaces. The aromas were determined by GC-MS, and the quality was evaluated by a group of expert tasters. The aromatic compounds, some of which came from the wines themselves and others which came from the wood, all increased in concentration by the end of the aging process. The ratio between cis- and trans-whiskylactone contents in wines reflected the different types of oak wood used. The note "vanilla" used by the tasters is probably not totally due to the presence of vanillin. The wines of best quality were those with a natural tannin content which had been aged in American oak, whereas the wines to which enological tannin had been added but aged in the same wood were considered the worst. An equalizing effect on the sensorial wines qualities was seen to result from the use of French oak. The furfural, eugenol, and cis-, and in some cases trans-, whiskylactone contents identified the wines from the different classes of wood. The wood from which the barrels were made had a greater effect on wines differentiation than the tannin content.

4-Butyrolactone↗
PubMed2004

Procedure to measure the level of polycyclic aromatic hydrocarbons in wood ashes used as fertilizer in agroforestry soils and their transfer from ashes to water.

Before wood ash can be safely used as a fertilizer in soils, possible negative effects such as input of organic contaminants or remobilization of contaminants already stored in the soil must be investigated. The objective of this study was to optimize and characterize extraction methods to isolate and quantitatively measure polycyclic aromatic hydrocarbons (PAHs) concentrations in wood ash that can be used as amendment of soils. It will be then possible to examine the effects of wood ash application on PAHs concentrations in the washing waters with the aim of evaluating their distribution by storage in the different compartments and what influences their stability and persistence. Simple, rapid and inexpensive methods have been set up for the determination of seven polycyclic aromatic hydrocarbons (PAHs) in wood ashes and ash aqueous extracts without interferences from other chemical contaminants using organic solvent extraction and/or SPE techniques and analyzed by an optimized RP-HPLC-FLD method. The feasibility of extraction for the determination of PAHs in wood ashes has been evaluated because PAHs are strongly sorbed to such a matrix, which explains why the PAHs content in ash was seldom studied. The method resulted to be of recoveries ranging from 81 to 97% for the different PAHs, with repeatabilities (RSDs%) better than 6%. Detection levels were from 0.2 to 2.2 microg/kg, while quantification limits were from 0.7 to 5.6 microg/kg, low enough to evaluate the presence of PAHs in wood ashes.

Agriculture↗
PubMed2006

Estimation of wood density and chemical composition by means of diffuse reflectance mid-infrared Fourier transform (DRIFT-MIR) spectroscopy.

Sitka spruce (Picea sitchensis) samples (491) from 50 different clones as well as 24 different tropical hardwoods and 20 Scots pine (Pinus sylvestris) samples were used to construct diffuse reflectance mid-infrared Fourier transform (DRIFT-MIR) based partial least squares (PLS) calibrations on lignin, cellulose, and wood resin contents and densities. Calibrations for density, lignin, and cellulose were established for all wood species combined into one data set as well as for the separate Sitka spruce data set. Relationships between wood resin and MIR data were constructed for the Sitka spruce data set as well as the combined Scots pine and Sitka spruce data sets. Calibrations containing only five wavenumbers instead of spectral ranges 4000-2800 and 1800-700 cm(-1) were also established. In addition, chemical factors contributing to wood density were studied. Chemical composition and density assessed from DRIFT-MIR calibrations had R2 and Q2 values in the ranges of 0.6-0.9 and 0.6-0.8, respectively. The PLS models gave residual mean squares error of prediction (RMSEP) values of 1.6-1.9, 2.8-3.7, and 0.4 for lignin, cellulose, and wood resin contents, respectively. Density test sets had RMSEP values ranging from 50 to 56. Reduced amount of wavenumbers can be utilized to predict the chemical composition and density of a wood, which should allow measurements of these properties using a hand-held device. MIR spectral data indicated that low-density samples had somewhat higher lignin contents than high-density samples. Correspondingly, high-density samples contained slightly more polysaccharides than low-density samples. This observation was consistent with the wet chemical data.

Cellulose↗
PubMed2003

Checking the geographical origin of oak wood: molecular and statistical tools.

New methods for better identification of timber geographical origin would constitute an important technical element in the forest industry, for phytosanitary certification procedures or in the chain of custody developed for the certification of timber from sustainably managed forests. In the case of the European white oaks, a detailed reference map of chloroplast (cp) DNA variation across the range exists, and we propose here to use the strong geographical structure, characterized by a differentiation of western vs. eastern populations, for the purpose of oak wood traceability. We first developed cpDNA markers permitting the characterization of haplotype on degraded DNA obtained from wood samples. The techniques were subsequently validated by confirming the full correspondence between genotypes obtained from living tissues (buds) and from wood collected from the same individual oak. Finally, a statistical procedure was used to test if the haplotype composition of a lot of wood samples is consistent with its presumed geographical origin. Clearly, the technique cannot permit the unambiguous identification of wood products of unknown origin but can be used to check the conformity of genetic composition of wood samples with the region of alleged origin. This could lead to major applications not only in the forest industry but also in archaeology or in palaeobotany.

DNA Primers↗
PubMedDate not supplied

Expressed sequence tags from poplar wood tissues--a comparative analysis from multiple libraries.

Xylogenesis involves successive developmental processes--cambial division, cell expansion and differentiation, cell death--each occurring along a gradient from the cambium to the pith of the stem. Taking advantage of the high level of organisation of wood tissues, we isolated cambial zone (CZ), differentiating xylem (DX) and mature xylem (MX) from both tension wood (TW) and opposite wood (OW) of bent poplars. Four different cDNA libraries were then constructed and used to generate 10,062 EST, reflecting the genes expressed in the different wood tissues. For the most abundant clusters, the EST distributions were compared between libraries in order to identify genes specific or over-represented at some specific developmental stages. They clearly showed a developmental shift between CZ and DX, whereas there is a continuity of development between DX and MX. CZ was mainly characterized by clusters of genes involved in cell cycle, protein synthesis and fate. Interestingly, two clusters with no assigned function were found specific to the cambial zone. In DX and MX, clusters were mostly involved in methylation of lignin precursors and microtubule cytoskeleton. In addition, in DX, EST from TW and OW were compared: five clusters of arabinogalactan proteins, one for sucrose synthase and one for fructokinase were specific or over-represented in TW. Moreover, a putative transcription factor and a cluster of unknown function were also identified in DX-TW. The informative comparison of multiple libraries prepared from wood tissues led to the identification of genes--some with still unknown functions--putatively involved in xylogenesis and tension wood formation.

Cell Cycle↗