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1.
Thérèse Sergent Stéphane Kohnen Benoit Jourez Cécile Beauve Yves-Jacques Schneider Caroline Vincke 《Wood Science and Technology》2014,48(5):1005-1017
Robinia pseudoacacia L. heartwood is characterized by a very high natural durability. However, a significant difference was observed between the mature and juvenile heartwood, the latter presenting less durability against fungi decay, which could be attributed to lower extractive content. In order to elucidate this idea, extractives from mature and juvenile heartwoods of black locust trees were investigated. Results showed that extractive and phenolic contents were higher in mature than in juvenile heartwoods. The identification of phenolic compounds by UPLC–DAD–MS/MS revealed, for the first time, the presence of resveratrol and piceatannol. These two stilbenes as well as the flavonoid dihydrorobinetin were present at the highest level in mature heartwood, and as they are known antifungals, they could account for the great durability of mature heartwood. The stilbenes were detected in significant amounts particularly in mature heartwood where piceatannol reached a level tenfold higher than that reported for Japanese knotweed roots, the primary natural source of these stilbenes, whereas resveratrol level was comparable with reported values. As resveratrol and piceatannol receive increasing demand for nutraceutical, cosmetic and, possibly, pharmaceutical purposes, due to their beneficial health effects, this study underlines the use of R. pseudoacacia as a promising sustainable and economical source of resveratrol and piceatannol. 相似文献
2.
Ana Lourenço Isabel Baptista Jorge Gominho Helena Pereira 《Journal of Wood Science》2008,54(6):464-469
The pulping wood quality of Acacia melanoxylon was evaluated in relation to the presence of heartwood. The sapwood and heartwood from 20 trees from four sites in Portugal
were evaluated separately at 5% stem height level in terms of chemical composition and kraft pulping aptitude. Heartwood had
more extractives than sapwood ranging from 7.4% to 9.5% and from 4.0% to 4.2%, respectively, and with a heartwood-to-sapwood
ratio for extractives ranging from 1.9 to 2.3. The major component of heartwood extractives was made up of ethanol-soluble
compounds (70% of total extractives). Lignin content was similar in sapwood and heartwood (21.5% and 20.7%, respectively)
as well as the sugar composition. Site did not influence the chemical composition. Pulping heartwood differed from sapwood
in chemical and optical terms: lower values of pulp yield (53% vs 56% respectively), higher kappa number (11 vs. 7), and lower
brightness (28% vs 49%). Acacia melanoxylon wood showed an overall good pulping aptitude, but the presence of heartwood should be taken into account because it decreases
the raw-material quality for pulping. Heartwood content should therefore be considered as a quality variable when using A. melanoxylon wood in pulp industries 相似文献
3.
Adam M. Taylor Barbara L. Gartner Jeffrey J. Morrell K. Tsunoda 《Journal of Wood Science》2006,52(2):147-153
The effect of selective removal of extractives on termite or decay resistance was assessed with matched samples of Thuja plicata Donn ex D. Don and Chamaecyparis nootkatensis (D.Don) Spach heartwood. Samples were extracted using a variety of solvents and then exposed to the subterranean termite
Coptotermes formosanus Shiraki in a no-choice feeding test or to the brown-rot fungus Postia placenta (Fr.) M. Larsen & Lombard in a soil bottle test. At the same time, the effect of naturally occurring variations in heartwood
extractives on termite or decay resistance was evaluated by testing samples from the inner and outer heartwood of five trees
of each species against C. formosanus and P. placenta and analyzing matched wood samples for their extractive content. The results suggest that the methanol-soluble extractives
in T. plicata and C. nootkatensis play an important role in heartwood resistance to attack by C. formosanus and P. placenta. Total methanol-soluble extractive content of the heartwood was positively correlated with both termite and decay resistance;
however, there was much unexplained variation and levels of individual extractive components were only weakly correlated with
one another. Further studies are under way to develop a better understanding of the relationships between individual extractive
levels and performance. 相似文献
4.
《Wood material science & engineering》2013,8(4):242-244
Abstract This study assessed the decay resistance of Pinus leucodermis wood to the brown-rot fungus Coniophora puteana. Based upon the median weight losses of 30.65% for heartwood and of 34.68% for sapwood obtained in the biological tests, both the heartwood and sapwood material examined was classified as not durable (durability class 5) according to the CEN/TS 15083-1 classification. Total extractives were low, 3.93% in heartwood and 1.00% in sapwood, while lignin content was 22.60% and 25.41% in heartwood and sapwood, respectively. It is highly recommended to use protective treatments before using P. leucodermis wood in outdoor conditions. 相似文献
5.
本文就中条山油松株内幼龄材与成熟材材性差异的比较研究,讨论对幼龄期划分的依据。根据木材解剖特征、物理力学性质的径向变异规律,确定其幼龄期为14年。随着树干高度的增加,油松木材幼龄期逐渐缩短、株内幼龄材范围及所占断面上的比例变小。株内幼龄材与成熟材材性差异显著。幼龄材管胞长度短、直径小,胞壁薄,微纤丝角度大,生长轮较宽,晚材率低,浸提物含量高,基本密度较大。幼龄材的力学强度远远小于成熟材。 相似文献
6.
Masanobu Tabata Takashi Kato Masatoshi Ohkubo Yasuhisa Abe Shuichiro Yoshinaga 《Journal of Forest Research》2002,7(2):105-112
The rot ofChamaecyparis obtusa (hinoki) trees was studied in the northern part of Kagawa Prefecture, Japan. Among 158 hinoki examined, butt rot was found
in 28.6, 58.3, and 100% of trees in the 29, 30, and 34-year-old stands, respectively. All trees with butt rot, and 11 trees
without it had rotted roots. Thirteen hinoki were peeled byCervus nippon (sika deer) and all of them were infected with butt rot. The maximum height of rot in deer-damaged trees was 2.6 m from the
ground level, but was 1.9 m in undamaged trees. About eighty-two percent of rotted trees showed rotted areas of less than
40 cm2 on the cross section of stems at the ground level. White mycelia and black flecks sometimes appeared in the rotted wood.
Basidiocarps of polyporaceous fungus were often found on felled logs and rotted stumps of hinoki and identified asPerenniporia subacida. Basidiomycetous fungus was isolated frequently from rotted wood of roots and stems, and determined to beP. subacida by comparative study on cultural characteristics. An inoculation experiment and wood-decay test proved that the fungus was
the cause of the rot of hinoki. Few absorbing roots of living trees were found in the clayey subsurface soil of the high dry
bulk density and the less soil aeration. Some absorbing roots had root rot and the rot spread from the base of the absorbing
root to the central part of the woody root. This is the first report on the rot of hinoki caused byP. subacida in Japan. 相似文献
7.
Peroxidase activity and isoenzymes of fresh wood samples of the third shoot of 12-year old trees and from the sapwood, transition
zone and heartwood of c. 60-year old stems of Scots pine (Pinus sylvestris L.) were investigated. Wood samples were ground at −30°C, extracted, and the extracts concentrated c. 20-fold for peroxidase
activity assays (guaiacol method) and for IEF-PAGE. At least 11 major isoenzymes could be found in the gels. Even the heartwood
contained some peroxidase isoenzymes. Isoenzyme patterns of the juvenile wood did not change with the season. However, juvenile
wood showed the highest peroxidase activity at the end of the growing season. Peroxidase activity decreased from the outer
sapwood towards the heartwood. Thin sections of different wood zones stained for peroxidase revealed activity in ray parenchyma
and resin canal epithelial cells. Intensive staining was localised in the bordered pits of vertical and ray tracheids, and
in the end walls of ray parenchyma cells. 相似文献
8.
R. Siepmann 《Forest Pathology》1977,7(5):287-296
Fomes annosus (Fr.) Cke. and other decay fungi in a Douglas fir stand, Pseudotsuga menziesii (Mirb.) Franco. 40% of the trees in a 40 years old Pseudotsuga menziesii stand showed butt rot. 85 trees were analysed for decay fungi. Fomes annosus, the most frequent fungus, also invaded the sap wood. Factors of the soil favourable to the rot and the possibility of transmission of the most frequent decay fungus, Fomes annosus, from (a) neighbouring spruce stands, (b) from the roots of Scots pine from the previous crop arc discussed. Caniophora puteana was isolated from about 10% of the butt rots. The importance of Calocera viscosa which grew out of the central decay of twelve trees as a decay fungus is still under investigation. 相似文献
9.
Heartwood is a determining factor of wood quality and understanding the biology of heartwood may allow us to control its formation. Heartwood formation is a form of senescence that is accompanied by a variety of metabolic alterations in ray parenchyma cells at the sapwood-heartwood transition zone. Although senescence has been studied at the molecular level with respect to primary growth, the cell maturation and death events occurring during heartwood formation have been difficult to study because of their location and timing. Analysis of global gene expression patterns during the transition from sapwood to heartwood may offer a powerful means of identifying the mechanisms controlling heartwood formation. Previously, we developed cDNA microarrays carrying 2567 unigenes derived from the bark/cambium region, sapwood and transition zone of a mature black locust tree. Here, we describe the use of these microarrays to characterize seasonal changes in the expression patterns of 1873 genes from the transition zone of mature black locust trees. When samples collected in summer and fall were compared, 569 genes showed differential expression patterns: 293 genes were up-regulated (> twofold) in summer (July 5) and 276 genes were up-regulated in fall (November 27). More than 50% of the secondary and hormone metabolism-related genes on the microarrays were up-regulated in summer. Twenty-nine out of 55 genes involved in signal transduction were differentially regulated, suggesting that the ray parenchyma cells located in the innermost part of the trunk wood react to seasonal changes. We established the expression patterns of 349 novel genes (previously unknown or no-hit), of which 154 were up-regulated in summer and 195 were up-regulated in the fall. 相似文献
10.
Outi Karppanen Martti Venäläinen Anni M. Harju Tapio Laakso 《Annals of Forest Science》2008,65(6):610-610
11.
J. Nault 《Wood Science and Technology》1988,22(1):73-80
Summary Radial distribution of thujaplicins in western red cedar (Thuja plicata Donn) trees of varying ages was studied in order to assess relative decay resistance of their wood. Samples were extracted with ethanol: benzene (1: 2), and the extractives were analyzed for thujaplicin codtent by a new method utilizing capillary gas chromatography of their methylated derivatives. The combined concentration of thujic acid and methyl thujate was also determined for each sample. Distribution of extractives, thujaplicins and thujic acid, generally increased from pith to outside heartwood, then decreased in the sapwood. Maximum extractive and thujaplicin contents were also related to tree age. This suggests that products made from the wood of younger trees will be less resistant to decay than similar products made from the wood of old trees. 相似文献
12.
Environmental and stand conditions related to Fistulina hepatica heart rot attack on Castanea sativa
Castanea sativa forests in north‐eastern Spain have historically been healthy and have been good producers of timber and non‐wood forest products. In the last quarter of a century, Fistulina hepatica has gained relevance in this ecosystem and is believed to be responsible for Chestnut Red Stain (CRS), which inflicts heart rot in trees and causes severe economic losses. The fungus grows in the heartwood and produces no external symptoms that would enable early detection. With the objective of developing an inexpensive method to detect heart rot and to discover possible relationships between the severity of F. hepatica attack and the silvicultural management or site characteristics of chestnut stands, 38 pure C. sativa plots were selected, sampled and analysed for the presence of the fungus. DNA was extracted from the heartwood samples, and PCR was used to amplify target sequences with specific F. hepatica primers for non‐homologous ITS1 and ITS2 regions. Correlation analysis was used to inspect the multiple interactions among the environmental and management variables examined, and a predictive model was designed for forest managers to estimate the risk of infection. Both analyses revealed that stress variables were related to CRS severity. This result is especially relevant since temperatures are expected to rise in coming decades throughout the northern rim of the Mediterranean region, where chestnut is an important species. This study provides two tools for better managing chestnut forests in the coming years: an inexpensive and fast tool for diagnosis and a predictive model to estimate the risk of infection. 相似文献
13.
Heartwood extractives (nonstructural wood components) are believed to be formed from a combination of compounds present in the adjacent sapwood and materials imported from the phloem. The roles of local compounds and imported material in heartwood formation could have important implications for the wood quality of species having naturally durable wood. Stable isotope composition (delta(13)C) was analyzed to assess radial variation in sapwood extractives, and to estimate the relative importance of adjacent sapwood extractives and imported photosynthate in the formation of heartwood extractives. Cellulose and extractives from the outer 39 annual rings of six Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees were isolated and their delta(13)C composition determined. Although the extractives and the cellulose showed different absolute delta(13)C values, the patterns of change over time (as represented by the annual rings) were similar in most cases. Within an annual ring, carbon isotope ratios of extractives were correlated with the cellulose isotope ratio (R2 = 0.33 in sapwood, R2 = 0.34 in heartwood for aqueous acetone-soluble extractives; R2 = 0.41 in sapwood for hot-water-soluble extractives). These data suggest that some sapwood extractives are formed when the wood ring forms, and remain in place until they are converted to heartwood extractives many years later. Sapwood extractives appear to be important sources of materials for the biosynthesis of heartwood extractives in Douglas-fir. 相似文献
14.
The influence of rate of growth on the density and heartwood extractives content of eucalypt species
J. Wilkes 《Wood Science and Technology》1984,18(2):113-120
Summary Basic density and extractives content, of the sapwood and outer heartwood respectively, were compared for a fast-and a slow-grown tree in five, 40 year old, coppice clumps of each of six eucalypt species. Rate of growth did not appreciably influence extracted wood density, although outer heartwood extractives levels were significantly (P<0.05) higher in the larger stems. The juvenile core, as defined by radial variation in basic density, occupied a similar proportion of the tree diameter in the fast-and slow-grown trees, suggesting that sampling was effected in tissues of similar maturity in both tree groups.Helpful discussions with Dr. W. A. Heather, a co-worker, and Dr. W. E. Hillis, Visiting Fellow of this Department, are gratefully acknowledged 相似文献
15.
Genotype distribution of Raffaelea quercivora in the oak galleries and its composition in the mycangia of Platypus quercivorus 
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下载免费PDF全文 Raffaelea quercivora is the pathogenic fungus that causes Japanese oak wilt. The female monogynous ambrosia beetle, Platypus quercivorus, carries this fungus in mycangia on the pronotum. These beetles bore galleries in oak trees with their partners to produce offspring, and they deposit fungus on the gallery walls from their mycangia. The offspring mature in the gallery, before loading the fungal pathogen and flying from the gallery to other healthy trees. To investigate the unloading and loading modes of the fungus within the gallery, we developed four polymorphic microsatellite markers for R. quercivora and identified the fungal genotypes in the galleries and mycangia of the beetles. Small wood chips were sampled at 5–10‐mm intervals from the walls of five galleries in a dead Quercus serrata tree. The pronota were also sampled from five female adult beetles. The genotypes of the R. quercivora isolates from the wood chips and pronota were identified using the microsatellite makers. The genotypic analysis showed that each gallery was inhabited patchily by 5–10 genotypes of R. quercivora, and the mycangia of each beetle contained 3–6 genotypes. These results indicate that diverse R. quercivora genotypes are unloaded repeatedly from the mycangia of female beetles onto the gallery wall, which results in their patchy distribution on the walls. When the offspring leave the host tree, the fungal clones that proliferate in the walls are also loaded repeatedly into the mycangia of the mature beetles. 相似文献
16.
Satomi Koretsune Kenji Fukuda Zhaoyang Chang Fuchen Shi Atsushi Ishida 《Journal of Forest Research》2009,14(2):88-94
We studied the importance of effective rainfall for interannual variation in water use efficiency (WUE) and tree-ring growth
of Chinese pine (Pinus tabulaeformis Carr.) and black locust (Robinia pseudoacacia L.) by examining correlations of seasonal precipitation with annual values of stable carbon isotope ratio (δ13C) and tree-ring width in early and late wood. The correlations with precipitation were examined for each month and for periods
of all possible lengths from 2 to 22 months starting from January of the previous year to October of the current year. The
period with the highest correlation was adopted as the most effective rainfall season for interannual variations in WUE and
tree-ring width. In early wood, precipitation during the dry season (October to May) before the growing season was negatively
correlated with δ13C in pine trees and positively correlated with ring width in pine and locust trees. In late wood, rainfall during the growing
season in the current year was negatively correlated with δ13C in pine and locust trees, and positively correlated with ring width in locust trees. Our results demonstrated the differences
in the water use strategies of pine and locust trees. The δ13C in pines indicated higher WUE and more conservative water use than in locust trees. Precipitation during the dry season
affected the interannual variation in WUE and tree-ring growth in pine and locust trees, indicating that rainfall during the
dry season is important for carbon gain and tree-ring growth during the following growing season. 相似文献
17.
《Southern Forests》2013,75(3):215-220
The infection and association between the wood wasp Sirex noctilio and the fungus Amylostereum areolatum is responsible for large-scale tree mortality in the Midlands of the KwaZulu-Natal province in South Africa. An exploratory investigation on the effect of the infestation of trees by the wood wasp and its associated fungus on the chemical composition of Pinus patula pulpwood was undertaken. Various tree classes representing different levels of physiological growth stress from this infestation were compared. Together with the above stress agents, fire damage to P. patula trees was also considered as a possible cause of changes in pulpwood chemical composition. Chemical analyses to determine the Seifert cellulose and Klason lignin contents as well as the levels of water- and solvent-soluble extractives were conducted using published Tappi standard methods. The results indicated only negligible differences between infestation levels (tree classes) with respect to Seifert cellulose and Klason lignin contents. In contrast, highly significant differences were observed for solvent- and water-borne extractives. It is evident from the results that P. patula trees engage a defence strategy to counter the effects of the infestation and the resulting physiological stress. The results of the chemical analyses suggest that trees should not be harvested any younger than the intended rotation age of 12 years and at the time of harvesting all the biomass, including the infected wood, should be sent to the pulp mill. Fire-damaged trees can be utilised in the same way as healthy trees when applying the TMP process provided the charcoal on the outer bark is removed. The usefulness of a biplot to simultaneously display the various tree classes and their chemical composition is illustrated. 相似文献
18.
Heat treatment of wood at relatively high temperatures (in the range of 150–280°C) is an effective method to improve biological
durability of wood. This study was performed to investigate the effect of heat treatment process optimisation on the resistance
against fungal attack, including basidiomycetes, molds and blue stain fungi. An industrially used two-stage heat treatment
method under relatively mild conditions (<200°C) was used to treat the boards. Heat treatment of radiata pine sapwood revealed
a clear improvement of the resistance against the brown rot fungi Coniophora puteana and Poria placenta. Increasing process temperature and/or effective process time during the first process stage, the hydro thermolysis, appeared
to affect the resistance against C. puteana attack, but the effect on the resistance against P. placenta was rather limited. Heat treated radiata pine showed a limited resistance against the white rot fungus Coriolus versicolor and process variations during the hydro thermolysis stage appeared not to affect this resistance. A clear difference between
the resistance of heat treated Scots pine sapwood and heartwood against fungal attack is observed. Scots pine heartwood showed
a higher resistance against C. puteana and P. placenta but also against the white rot fungus C. versicolor. Similar results were obtained when heat treated birch was exposed to brown and white rot fungi. Heat treatment showed an
improved resistance against C. puteana attack, especially at higher temperatures during the hydro thermolysis stage. A clear improvement of the durability was also
observed after exposure to the white rot fungus C. versicolor and especially Stereum hirsutum. Increasing the process temperature or process time during the hydro thermolysis stage appeared to have a limited effect
on the resistance against C. versicolor attack. Heat treated radiata pine and Norway spruce were still susceptible to mold growth on the wood surface, probably due
to the formation of hemicelluloses degradation products (e.g. sugars) during heat treatment. Remarkable is the absence of
blue stain fungi on heat treated wood specimen, also because the abandant blue stain fungi were observed on untreated specimen.
Molecular reasons for the resistance of heat treated wood against fungal attack are discussed in detail contributing to a
better understanding of heat treatment methods. 相似文献
19.
The decay pattern in bamboo fibers caused by a brown rot fungus, Gloeophyllum trabeum, was examined by microscopy. The inner part of the polylaminate secondary wall was degraded, while the outer part of the
secondary wall remained essentially intact. Degradation in bamboo fiber walls without direct contact with the fungal hyphae
was similar to wood decay caused by brown rot fungi. Degradation in polylaminate walls was almost confined to the broad layers
whereas the narrow layers appeared resistant. The p-hydroxylphenyl unit lignin in middle lamella, particularly in the cell corner regions, was also degraded. The degradation
of lignin in bamboo fibers was evidenced by Fourier transform infrared spectra. The present work suggests that the decay of
bamboo fiber walls by G. trabeum was influenced by lignin distribution in the fiber walls as well as the polylaminate structures. 相似文献
20.
Gunthard Scholz Falk Liebner Gerald Koch Claus-Thomas Bues Björn Günther Ernst Bäucker 《Wood Science and Technology》2007,41(8):673-686
The very decorative heartwood of Brosimum guianense is internationally well known. Snakewood, as it is colloquially known, is represented in wood databases (e.g. the DELTA or
InsideWood) as well as in lists of commercial timbers of many timber trading companies. The very decorative heartwood is hardly
available and gains prices of up to 25 €/kg in form of half stems. In the present study, the chemical composition and especially
the subcellular cell structure was analysed by means of UV microspectrophotometry to explain the high natural durability and
some extraordinary physical properties in addition to the anatomical composition. The heartwood consists of approximately
39% lignin, 54% carbohydrates and 0.4% lipophilic compounds of unspecified origin. The fibres are very thick-walled. Numerous
sclerotic tyloses and organic deposits are present in the vessel. The extractives in high content are also components of parenchyma
cells as well as in tyloses, respectively. These detected phenolic extractives, partly of flavonoid character, are also part
of the cell wall. Calcium oxalate crystals are deposited in the upright and square cells of rays and sporadically in axial
parenchyma cells. These facts are reasons for the famous natural durability of Snakewood. The sapwood density ranges from
1.1 to 1.4 g/cm3 for heartwood (12% mc). The compression strength (119 N/mm2), the bending strength (241 N/mm2), the modulus of elasticity (23,200 N/mm2) and the hardness (196 N/mm2) indicate exceedingly high elastomechanical properties. 相似文献