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1.
Gutierrez A del Rio JC Martinez MJ Martinez AT 《Applied and environmental microbiology》1999,65(4):1367-1371
Solid-state fermentation of eucalypt wood with several fungal strains was investigated as a possible biological pretreatment for decreasing the content of compounds responsible for pitch deposition during Cl2-free manufacture of paper pulp. First, different pitch deposits were characterized by gas chromatography (GC) and GC-mass spectrometry (MS). The chemical species identified arose from lipophilic wood extractives that survived the pulping and bleaching processes. Second, a detailed GC-MS analysis of the lipophilic fraction after fungal treatment of wood was carried out, and different degradation patterns were observed. The results showed that some basidiomycetes that decreased the lipophilic fraction also released significant amounts of polar extractives, which were identified by thermochemolysis as originating from lignin depolymerization. Therefore, the abilities of fungi to control pitch should be evaluated after analysis of compounds involved in deposit formation and not simply by estimating the decrease in the total extractive content. In this way, Phlebia radiata, Funalia trogii, Bjerkandera adusta, and Poria subvermispora strains were identified as the most promising organisms for pitch biocontrol, since they degraded 75 to 100% of both free and esterified sterols, as well as other lipophilic components of the eucalypt wood extractives. Ophiostoma piliferum, a fungus used commercially for pitch control, hydrolyzed the sterol esters and triglycerides, but it did not appear to be suitable for eucalypt wood treatment because it increased the content of free sitosterol, a major compound in pitch deposits. 相似文献
2.
González-Vila FJ Bautista JM Gutiérrez A Del Rio JC González AG 《Journal of biochemical and biophysical methods》2000,43(1-3):345-351
Various typical lipid components of wood extractives have been isolated from Eucalyptus globulus wood by supercritical carbon dioxide modified with methanol. The influence of various extraction parameters on the yield and qualitative composition of the extracts have been studied. The extracts were analyzed by gas chromatography-mass spectrometry and compared with those obtained by Soxhlet extraction with acetone, the standard method for the determination of wood extractives. The qualitative and quantitative results obtained by both methods were in good agreement. The experimental planning to asses the influence of pressure, temperature and percentage of methanol and their interactions on the extraction efficiency was carried out with a factorial design, followed by multiple linear regression algorithm. 相似文献
3.
Eucalyptus globulus wood fractionation by autohydrolysis and organosolv delignification 总被引:1,自引:0,他引:1
This work provides an assessment on the fractionation of Eucalyptus globulus wood by sequential stages of autohydrolysis (to cause the solubilization of hemicelluloses) and organosolv pulping (to dissolve lignin, leaving solids enriched in cellulose). With this approach, valuable products (hemicellulose-derived saccharides, sulphur-free lignin fragments and cellulosic substrates with low contents of residual hemicelluloses) are obtained in separate streams, according to the biomass refinery approach. Autohydrolysis was carried out under optimized operational conditions, and organosolv pulping was performed using uncatalyzed ethanol-water solutions. The effects of the most influential operational variables (autohydrolysis severity, delignification temperature and ethanol concentration in the organosolv stage) on solid yield, solid composition, cellulose susceptibility and recovery of the various fractions was assessed using statistical methods, which enabled the identification of the most favourable operational conditions. 相似文献
4.
Jules S. Freeman Simon P. Whittock Brad M. Potts René E. Vaillancourt 《Tree Genetics & Genomes》2009,5(4):713-722
Regions of the genome affecting physical and chemical wood properties (quantitative trait loci (QTL)), as well as growth,
were identified using a clonally replicated, outbred F2 family (112 genotypes, each with two ramets) of Eucalyptus globulus, planted in a field trial in north-west Tasmania. Traits studied were growth (assessed by stem diameter), wood density, cellulose
content, pulp yield and lignin content. These traits are important in breeding for pulpwood, and will be important in breeding
for carbon sequestration and biofuel production. Between one and four QTL were located for each trait, with each QTL explaining
between 4% and 12% of the phenotypic variation. Several QTL for chemical wood properties were co-located, consistent with
their high phenotypic correlations, and may reflect pleiotropic effects of the same genes. In contrast, QTL for density and
lignin content with overlapping confidence intervals were considered to be due to independent genes, since the QTL effects
were inherited from different parents. The inclusion of fully informative microsatellites on the linkage map allowed the determination
of homology at the linkage group level between QTL and candidate genes in different pedigrees of E. globulus and different eucalypt species. None of the candidate genes mapped in comparable studies co-located with our major QTL for
wood chemical properties, arguing that there are important candidate genes yet to be discovered. 相似文献
5.
Generation of xylose solutions from Eucalyptus globulus wood by autohydrolysis-posthydrolysis processes: posthydrolysis kinetics 总被引:2,自引:0,他引:2
Eucalyptus wood samples were treated with water under selected operational conditions (autohydrolysis reaction) to obtain a liquid phase containing hemicellulose-decomposition products (mainly acetylated xylooligosaccharides, xylose and acetic acid). In a further acid-catalysed step (posthydrolysis reaction), xylooligosaccharides were converted into xylose, a carbon source for further fermentation. The kinetic pattern governing the posthydrolysis step was established by reacting xylooligosaccharide-containing liquors at 100.5 degrees C, 115 degrees C, 125 degrees C or 135 degrees C in media containing 0.5, 1.0, 1.5 or 2 wt% of catalyst (sulphuric acid). The time course of the concentrations of xylooligosaccharides, xylose, furfural and acetic acid were determined, and the results were interpreted by means of a kinetic model which allowed a close reproduction of the experimental data. Almost quantitative conversion of xylooligosaccharides into xylose was achieved under a variety of experimental conditions. The first-order, kinetic coefficient for xylooligosaccharide hydrolysis (k1, h(-1)) varied with both temperature (T, K) and molar sulphuric acid concentration (C) according to the equation In k1 = 36.66 + 1.00lnC - 108.0/(8.314T). The hydrolysis of acetyl groups followed a first-order kinetics. The corresponding kinetic coefficient (ka, h(-1) was correlated with the operational conditions by the equation Inka = 26.80+ 1.18 InC - 73.37/(8.314T). 相似文献
6.
Eucalyptus spp. are among the highest isoprene emitting plants. In the Mediterranean area these plants are often cultivated along the seashore and cope with recurrent salt stress. Transient salinity may severely but reversibly reduce photosynthesis and stomatal conductance of Eucalyptus globulus leaves but the effect on isoprene emission is not significant. When the stress is relieved, a burst of isoprene emission occurs, simultaneously with the recovery of photosynthetic performance. Later on, photosynthesis, stomatal conductance, and isoprene emission decay, probably because of the onset of leaf senescence. Isoprene emission is not remarkably affected by the stress at different light intensities, CO(2) concentrations, and leaf temperatures. When CO(2) was removed and O(2) was lowered to inhibit both photosynthesis and photorespiration, we found that the residual emission is actually higher in salt-stressed leaves than in controls. This stimulation is particularly evident at high-light intensities and high temperatures. The maximum emission occurs at 40 degrees C in both salt-stressed and control leaves sampled in ambient air and in control leaves sampled in CO(2)-free and low-O(2) air. However, the maximum emission occurs at 45 degrees C in salt-stressed leaves sampled in CO(2)-free and low-O(2) air. Our results suggest the activation of alternative non-photosynthetic pathways of isoprene synthesis in salt-stressed leaves and perhaps in general in leaves exposed to stress conditions. The temperature dependence indicates that this alternative synthesis is also under enzymatic control. If this alternative synthesis still occurs in the chloroplasts, it may involve a thylakoid-bound isoprene synthase. 相似文献
7.
Cambial growth and wood properties respond to fluctuating environmental conditions. Understanding the nature of these responses
is crucial to understanding their cumulative effect on the wood quality characteristics of a forest stand. This paper reports
on a study conducted over a period of 3? years in continuously irrigated, alternately irrigated and non-irrigated Eucalyptus globulus, in which changes in wood density occurring in response to short-term growth responses were examined. The study showed that
continuous irrigation led to the production of wood with significantly more homogenous density than was the case in situations,
where trees experienced large fluctuations in temporal water availability. Although the trees which were not irrigated had
the highest wood density overall, trees in which growth was relatively continuous tended to produce the largest volumes of
wood with relatively high density, compared to trees in which periodic growth responses were caused by intermittent irrigation,
in which wood density was actually reduced. This was largely due to more growth days in summer under the conditions of higher
radiation, and a reduction in the number of growth events leading to the production of disproportionately large amounts of
low density wood. Soil water deficits contributed to density variation in all treatments, but the effect of energy limitations
became more important in continuously irrigated trees. 相似文献
8.
João Costa e Silva Nuno M. G. Borralho José A. Araújo René E. Vaillancourt Brad M. Potts 《Tree Genetics & Genomes》2009,5(2):291-305
Genetic variation and co-variation among the key pulpwood selection traits for Eucalyptus globulus were estimated for a range of sites in Portugal, with the aim of improving genetic parameters used to predict breeding values
and correlated response to selection. The trials comprised clonally replicated full-sib families (eight trials) and unrelated
clones (17 trials), and exhibited varying levels of pedigree connectivity. The traits studied were stem diameter at breast
height, Pilodyn penetration (an indirect measure of wood basic density) and near infrared reflectance predicted pulp yield.
Univariate and multivariate linear mixed models were fitted within and across sites, and estimates of additive genetic, total
genetic, environmental and phenotypic variances and covariances were obtained. All traits studied exhibited significant levels
of additive genetic variation. The average estimated within-site narrow-sense heritability was 0.19 ± 0.03 for diameter and
0.29 ± 0.03 for Pilodyn penetration, and the pooled estimate for predicted pulp yield was 0.42 ± 0.14. When they could be
tested, dominance and epistatic effects were generally not statistically significant, although broad-sense heritability estimates
were slightly higher than narrow-sense heritability estimates. Averaged across trials, positive additive (0.64 ± 0.08), total
genetic (0.58 ± 0.04), environmental (0.38 ± 0.03) and phenotypic (0.43 ± 0.02) correlation estimates were consistently obtained
between diameter and Pilodyn penetration. This data argues for at least some form of pleiotropic relationship between these
two traits and that selection for fast growth will adversely affect wood density in this population. Estimates of the across-site
genetic correlations for diameter and Pilodyn penetration were high, indicating that the genotype by environment interaction
is low across the range of sites tested. This result supports the use of single aggregated selection criteria for growth and
wood density across planting environments in Portugal, as opposed to having to select for performance in different environments. 相似文献
9.
10.
Two new acylphloroglucinols were isolated from the leaves of Eucalyptus globulus Labill and identified as macrocarpals P (1) and Q (2). Structural elucidations were carried out using conventional 1D and 2D NMR and mass spectrometry together with complementary techniques (UV and IR). Macrocarpal Q was a diastereoisomer of macrocarpal E (3), configuration of which was not precised. Simultaneous isolation of macrocarpals E and Q allowed to determine the configurations of both compounds. The diformylphloroglucinol (4) was also isolated as well as already known compounds grandinol, macrocarpals D, I, L, N, O and am-1. 相似文献
11.
A glucuronoxylan was extracted from the holocellulose of Eucalyputus globulus wood with 10% KOH and subjected to hydrolysis by a commercial cellulase preparation “Meicelase”. Neutral xylooligosaccharides liberated were analyzed by size exclusion chromatography. Aldouronic acids liberated were purified by preparative anion exchange chromatography. Their structures were studied by monosaccharide analysis, comparison of volume distribution coefficients (Dvs) in anion exchange chromatography with those of the authentic samples, and 1H and 13C NMR spectroscopy, resulting in the characterization of seven aldouronic acids including a novel one containing galactose residue.O-β-d-Xylp-(1 → 4)-[O-(4-O-Me-α-d-GlcAp)-(1 → 2)]-O-β-d-Xylp-(1 → 4)-O-β-d-Xylp-(1 → 4)-d-XylO-(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-O-β-d-Xylp-(1 → 4)-d-XylO-(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-d-XylO-β-d-Xylp-(1 → 4)-O-β-d-Xylp-(1→3)-O-α-l-Rhap-(1 → 2)-O-α-l-GalAp-(1 → 4)-d-XylO-β-d-Xylp-(1 → 4)-O-β-d-Xylp-(1 → 3)-O-α-l-Rhap-(1 → 2)-d-GalAO-β-d-Xylp-(1 → 3)-O-α-l-Rhap-(1 → 2)-O-α-d-GalAp-(1 → 4)-d-XylO-β-d-Galp-(1 → 2)-O-(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-O-β-d-Xylp-(1 → 4)-d-Xyl.The oligosaccharides liberated provide information on multiplicity of xylanases secreted by Trichoderma viride. The presence of the last aldouronic acid shows a structural feature of E. globulus xylan. 相似文献
12.
从蓝桉果实乙醇提取物的乙酸乙酯部位分离得到7个五环三萜化合物,经理化和波谱分析鉴定为3β-乙酰基-乌索-11,12-烯-28,13β内酯(1)、桦木酮酸(2)、白桦脂酸(3)、2α-羟基白桦脂酸(4)、2α,3β-二羟基乌苏-12-烯-28-酸(5)、熊果酸(6)、3β-羟基-乌索-11,12-烯-28,13β内酯(7),其中化合物1,4,5和7系首次从该植物中分离得到。 相似文献
13.
A heteroxylan was isolated from Eucalyptus globulus wood by extraction of peracetic acid delignified holocellulose with dimethyl sulfoxide. Besides (1-->4)-linked beta-D-xylopyranosyl units of the backbone and short side chains of terminal (1-->2)-linked 4-O-methyl-alpha-D-glucuronosyl residues (MeGlcA) in a 1:10 molar ratio, this hemicellulose contained galactosyl and glucosyl units attached at O-2 of MeGlcA originating from rhamnoarabinogalactan and glucan backbones, respectively. About 30% of MeGlcA units were branched at O-2. The O-acetyl-(4-O-methylglucurono)xylan showed an acetylation degree of 0.61, as determined by 1H NMR spectroscopy, and a weight-average molecular weight (M(w)) of about 36 kDa (P=1.05) as revealed from size-exclusion chromatography (SEC) analysis. About half of the beta-D-xylopyranosyl units of the backbone were found as acetylated moieties at O-3 (34 mol%), O-2 (15 mol%) or O-2,3 (6 mol%). Practically, all beta-D-xylopyranosyl units linked at O-2 with MeGlcA residues were 3-O-acetylated (10 mol%). 相似文献
14.
Padma S. Vankar Jyoti Srivastava Krešimir Molčanov Biserka Kojic-Prodić 《Phytochemistry letters》2009,2(2):67-71
A new steroidal lactone of the Withanolide A series has been isolated from the supercritical fluid extract of Eucalyptus globulus L. (bark) as a major component (I) along with a known structurally similar steroidal lactone as minor component (II). The structural identification of the new lactone was accomplished by different spectroscopic techniques viz. 1H and 13C NMR, etc. The relative stereochemistry was unequivocally determined from the X-ray crystallography. 相似文献
15.
Four ellagic acid rhamnosides were isolated from the stem bark of Eucalyptus globulus. Their structures have been established on the basis of the analysis of their 1H NMR, 13C NMR, HMBC, IR and MS spectral data. The HMBC data of these compounds were most useful for their structure determinations, with these bring determined to be 3-O-methylellagic acid 3'-O-alpha-rhamnopyranoside, 3-O-methylellagic acid 3'-O-alpha-3'-O-acetylrhamnopyranoside, 3-O-methylellagic acid 3'-O-alpha-2'-O-acetylrhamnopyranoside, 3-O-methylellagic acid 3'-O-alpha-4'-O-acetylrhamnopyranoside, respectively. Their antioxidant activities were evaluated by measuring the inhibition of lipid peroxidation using rat liver microsomes, with IC50 values of 10.0-14.0 microg/ml. 相似文献
16.
Rebecca C. Jones Ren�� E. Vaillancourt Peter L. Gore Brad M. Potts 《Tree Genetics & Genomes》2011,7(6):1209-1218
Understanding the factors affecting variation in phenology within a species is important as flowering time constitutes one
of the major barriers to gene flow. We studied the genetic and environmental control of flower initiation and anthesis time
in E. globulus ssp. globulus. For 5 years, flower initiation and anthesis were monitored in a seed orchard containing clones of 63 genotypes from four
different regions of the species’ natural distribution. Anthesis occurred over a long period each year, spanning as much as
9 months in 2008. This variation was under strong genetic control with little genotype by year interaction (broad-sense heritability,
Ĥ
2 = 0.78 ± 0.04). There were highly significant differences among regions; anthesis occurred earlier for Furneaux and Tasmania
than Strzelecki and Otways each year. Surprisingly though, there was little variation in flower initiation time between regions
and genotypes, and this was under weak genetic control (Ĥ
2 = 0.06 ± 0.05). The average anthesis time in the orchard varied from year to year, and there was evidence that heat sum was
a major driver of this environmental variation. Anthesis time is controlled by both genetic and environmental factors, with
the responses to each being predictable to some extent, and unrelated to the timing of flower initiation. 相似文献
17.
Summary Flooding for up to 40 days induced morphological changes and reduced growth of 6-week-old Eucalyptus camaldulensis and Eucalyptus globulus seedlings. However, the specific responses to flooding varied markedly between these species and with duration of flooding. Both species produced abundant adventitious roots that originated near the tap root and original lateral roots, but only E. camaldulensis produced adventitious roots on submerged portions of the stem. Flooding induced leaf epinasty and reduced total dry weight increment of seedling of both species but growth of E. globulus was reduced more. In both species dry weight increment of shoots was reduced more than dry weight increment of roots, reflecting compensatory growth of adventitious roots. Adaptation to flooding appeared to be greater in E. camaldulensis than in E. globulus. the importance of formation of adventitious roots in flooding tolerance is emphasized.Research supported by the College of Agricultural and Life Sciences, University of Wisconsin, Madison; CEPEC (Cacao Research Center), Bahia, Brazil; and BMBRAPA (Brazilian Research Institute), Brasilia, Brazil 相似文献
18.
Mariana Richero Mariana Barraco Vega Maria Pía Cerdeiras Gianna Cecchetto 《Trees - Structure and Function》2013,27(1):249-257
The genus Eucalyptus includes over 700 species, some of which are the most widely planted hardwoods worldwide. Each species and subspecies of Eucalyptus present different characteristics regarding its wood quality and yield. This fact makes it very important to work with known species/subspecies so as to optimize handling and conservation of forest resources. Some of them are morphologically very similar, making it difficult to differentiate by simple observation. This is the case with Euclyptus globulus ssp globulus and E. globulus ssp maidenii, which can only be distinguished in the adult tree. These issues can be avoided using well-characterized seeds. This can be quite expensive, especially for the small growers. An alternative approach is to develop simple methods for the differentiation of the two subspecies. In this work, we develop a quick method, based on SCAR molecular markers derived from RAPD molecular markers, for the differentiation of the subspecies of E. globulus, in particular E. globulus ssp globulus and E. globulus ssp maidenii. 相似文献
19.
Silvério FO Barbosa LC Maltha CR Fidêncio PH Cruz MP Veloso DP Milanez AF 《Bioresource technology》2008,99(11):4878-4886
Lipophilic wood extractives commonly referred to as pitch, cause significant problems for the pulp and paper industries. The reduction of these extractives is an important aspect that concerns industries around the world. In the present work the change in the amount and chemical composition of lipophilic extractives from Eucalyptus spp. stored for 20, 40, 60, 100, 140 and 180 days after harvesting was investigated. The results showed a decrease in extractives content with storage time, with the most significant decrease occurring 60 days after harvesting. In addition, fatty acids and sterols were the main classes of compounds responsible for the significant decrease in extractive content. Data were analyzed by principal component analysis. PC1 explains approximately 99% of the total variance, and beta-sitosterol was the major compound responsible for the differentiation. These studies demonstrate that in terms of economical aspects, quality of the pulp and paper and minimization of pitch formation, the best period of wood storage is 60 days. 相似文献
20.
Saravanan Thavamanikumar Luke J. McManus Peter K. Ades Gerd Bossinger Desmond J. Stackpole Richard Kerr Sara Hadjigol Jules S. Freeman René E. Vaillancourt Peng Zhu Josquin F. G. Tibbits 《Tree Genetics & Genomes》2014,10(6):1661-1678
The moderate to high levels of nucleotide diversity and low linkage disequilibrium found in many forest tree species make them ideal candidates for association mapping. Here, we report candidate gene-based association mapping results for complex wood quality and growth traits in Eucalyptus globulus Labill. ssp. globulus, the most widely grown eucalypt in temperate regions of the world. Ninety-eight single nucleotide polymorphisms (SNPs) from 20 wood quality candidate genes were assayed in a discovery population consisting of 385 trees sourced from a provenance-progeny trial. Twenty-five selected SNPs with significant associations (P?0.05) in the discovery population were assayed for validation in 296 trees sourced from an independent second-generation breeding trial. To account for background genetic structure, mixed models were used in the association analyses. Two associations identified in the discovery population were independently supported in the validation testing. However, combining the discovery and validation results in a combined analysis, we discovered nine stable marker-trait associations for seven traits. These associations link underlying complex wood and growth phenotypes to earlier putative selection signatures opening new avenues to accelerate the dissection of these traits. 相似文献