• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.213-222
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• 2010

In this study, chemical compositions - holocellulose, lignin and monomeric sugars - were characterized with two poplar wood cell walls, one of which was grown at normal condition (CPW) and the other was genetically modified by antisence suppression of CCoAOMT gene expression (ACPW). Milled wood lignins were isolated from CPW and ACPW and subjected to methoxyl group, DFRC, Py-GC/MS, GPC, $^{13}C$-NMR analysis, respectively. There were few differences in holocellulose contents in both cell walls, which were determined to 81.6% in CPW and to 82.3% in ACPW. However, lignin contents in ACPW was clearly decreased by the suppression of CCoAOMT gene expression. In CPW 21.7% of lignin contents was determined, while lignin contents in ACPW was lowered to 18.3%. The relative poor solubility of ACPW in alkali solution could be attributed to the reduction of lignin content. The glucose contents of CPW and ACPW were measured to 511.0 mg/g and 584.8 mg/g and xylose contents 217.8 mg/g and 187.5 mg/g, respectively, indicating that suppression of CCoAOMT gene expression could be also influenced to the formation of monomeric sugar compositions. In depth investigation for milled wood lignin (MWL) isolated from both samples revealed that the methoxyl contents at ACPW was decreased by 7% in comparison to that of CPW, which were indirectly evidenced by $^{13}C$-NMR spectra and Py-GC/MS. According to the data from Py-GC/MS S/G ratios of lignin in CPW and ACPW were determined to 0.59 and 0.44, respectively. As conclusive remark, the biosynthesis of syringyl unit could be further influenced by antisense suppression of CCoAOMT during phenylpropanoid pathway in the plant cell wall rather than that of guaiacyl unit.

• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.511-526
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• 2018

Effects of heat treatment on the characteristics of Royal paulownia (Paulownia tometosa) wood were investigated. The results were compared with those of Suwon silver poplar (Populus tementiglandulosa) and Korean red pine (Pinus densiflora) woods. The wood samples of the three species were treated at $160^{\circ}C$, $180^{\circ}C$, $200^{\circ}C$ and $220^{\circ}C$ in an electric furnace for 2 hours. The changes of color, density, mass loss, and relative crystallinity were investigated before and after heat treatment. The lightness ($L^*$) decreased rapidly from $200^{\circ}C$ in all species. There were no change in red-green chromaticity($a^*$) and yellow-blue chromaticity($b^*$) of Royal paulownia and poplar woods with increasing temperature. Whereas, yellow-blue chromaticity($b^*$) of Korean red pine wood decreased sharply from $200^{\circ}C$. Royal paulownia wood showed appreciable color change(${\Delta}E^*$) after heat treatment above $180^{\circ}C$. Poplar and pine woods, however, presented significant color change from $160^{\circ}C$. Color change of the three wood species increased rapidly with increasing temperature. Mass loss of the three wood species by heat treatment was the highest in the Royal paulownia wood and the lowest in the pine wood. Mass loss and relative crystallinity increased and density decreased slightly with increasing temperature. Consequently, it is revealed that Royal paulownia wood showed considerable differences in the temperature of color change, weight loss and change of relative crystallinity compared to the other wood species.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.372-380
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• 2009

After supercritical water treatment of poplar wood meals (passed through 60 mesh) for 60s between 325 and $425^{\circ}C$ at the fixed pressure at $220{\pm}10atm$, some solid residues were present in the degradation products. They mainly consisted of chemically modified lignin and fibrous materials. Glucose and xylose were identified as main sugar components of fibrous materials, and the highest ratio of glucose/xylose was achieved at the highest reaction temperature. As reaction temperature was elevated, the portion of fibrous materials decreased in the solid residues, while lignin was further accumulated. The H : G : S ratio of lignin in solid residues was estimated by analytical pyrolysis. Irrespective of reaction temperatures, the H:G:S ratios were not significantly changed in the lignin in solid residues. Compared to poplar milled wood lignin (MWL), it was remarkable that H type monomers were further lowered, while portion of S type monomers increased. The amount of G type monomers were relative stable. In presence of HCl catalyst, lowering H type as well as enhancing S type was further distinguishable. According to the result of nitrobenzene oxidation (NBO), ca. 265 mg of vanillin and syringaldehyde was yielded from poplar MWL as main products. However, remarkably reduced amount of NBO products were determined from solid residues by raising operating temperature as well as by the addition of HCl catalyst. These results strongly indicate that $\beta$-O-4 linkage could be easily cleaved during supercritical water treatment, so that the lignins in the solid residues seem to be condensed phenol polymers, which are mainly formed by carbon-carbon linkages rather than $\beta$-O-4 linkage.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.537-542
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• 2013

Field performance of somatic plants (somatic embryo derived-plants) of yellow-poplar (Liriodendron tulipifera) produced from somatic embryogenesis was compared with that of seedlings at age 5. In comparison of photosynthetic rate (seedling, $10.67{\mu}mol$ $CO_2m^{-2}s^{-1}$; somatic plant, $9.04{\mu}mol$ $CO_2m^{-2}s^{-1}$), stomatal conductance rate (seedling, 0.2 $H_2Om^{-2}s^{-1}$; somatic plant, 0.166 $H_2Om^{-2}s^{-1}$) and respiration rate (seedling, 1.71 mmol $H_2Om^{-2}s^{-1}$; somatic plant, 1.513 mmol $H_2Om^{-2}s^{-1}$), no significant differences were found between plants. The seedlings were a little higher in comparison of stomatal density (seedling, $23.33/mm^2$; somatic plant, $22.43/mm^2$), length (seedling, $25.83{\mu}m$; somatic plant, $23.46{\mu}m$) and width (seedling, $15.87{\mu}m$; somatic plant, $15.3{\mu}m$). In comparison of DNA content of the leaves using flow cytometry, no differences in ploidy level were found between the seedlings and somatic plants.

• Journal of Mushroom
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• v.7 no.4
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• pp.163-167
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• 2009

Ten to thirty percent of ginko nut shell(GNS) were added to poplar sawdust to investigate mycelial growth. Mycelial growth on the medium with GNS was 93~97(mm/28days) and was slower than that of the control without GNS as that of 101(mm/28 days). Mycelial growth time on medium of sawdust with 10% GNS was same with control without GNS as 28 days but that on medium with 20 to 30% GNS was delayed for 2 days. The time of pinhead formation of sawdust with 10 to 30% GNS was 7 days, the growth time to harvest was 5 days. Yields per volume of GNS added treatments were 80.5g to 91.8g, which was increased 14 to 30% compared to 70.8g of the control without GNS.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.409-415
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• 2017

The vegetation period of trees might be prolonged by the delay of the leaf senescence in autumn. Thus, we focused on the generation of senescence-delayed transgenic trees to enhance biomass production. The PagMYC2, a gene containing the basic helix-loop-helix domain, was selected as a candidate for a senescence-delayed transgenic tree. The PagMYC2 gene was specifically induced after treatment with phytohormone jasmonic acid, and upregulated by abiotic stresses such as salinity, osmotic pressure and a low temperature. The constitutive overexpression of the PagMYC2 delayed the leaf senescence and inhibited chlorophyll degradation in the transgenic poplars. Leaf senescence analysis was performed in the leaf tissues of the PagMYC2-over-expression transgenic poplars. The transgenic poplars exhibited higher photochemical efficiency than did a wild type plant under a short-day condition (6 hours light/18 hours darkness) or a low temperature condition ($15^{\circ}C$) that was similar to the weather conditions of autumn. These results suggest that the PagMYC2 is a useful genetic resource to improve biomass production, which is able to sustain growth with senescence-delayed leaves for a long time in autumn.

• The Korean Journal of Mycology
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• v.9 no.3
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• pp.123-128
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• 1981

Three edible species, e.g. Lyophyllum sp. and Armillaria mellea introduced from Japan in 1979 and Auriaularia auricula-judae from Taiwan in 1978 were selected for artifcial cultivation. The media, MSDS for Lyophyllum sp, MHS and PDS for A. auricula-judae, and MSDS and MHS for A. mellea were selected. The range of optimum pH of Lyophyllum sp. was 6.0 and pH 8.0 for A. auricula-judae and pH 6.0 to 7.0 for A. mellea. The range of optimum temperature for the mycelial growth of Lyophyllum sp. was 25 to $30^{\circ}C,\;30^{\circ}C$ for A. auricula-judae and $25^{\circ}C$ for A. mellea. When the moisture content 75 to 80% (w/w) in the substrates, the mycelial growth of Lyophyllum sp. and A. auricula-judae, was rapid. 65% (w/w) for A. mellea. As the spawning substrates, wheat for Lyophyllum sp. oak sawdust for A. auricula-judae and poplar sawdust for A. mellea were selected, respectively. In this experiment, yields of Lyophyllum sp. and A. auricula-judae were high on the poplar sawdust added 20% (w/w) of rice bran. Lyophyllum sp. and A. auricula-judae for sources of new edible mushrooms seems to be possible.

• The Korean Journal of Mycology
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• v.30 no.2
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• pp.99-103
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• 2002

The suitable sterilization conditions in pot cultivation of varieties of Chunchunutari-2-ho and Suhannutari-1-ho Pleurotus ostreatus were investigated. The substrate formulations for the cultivation consisted of 40% poplar sawdust, 40% waste cotton and 20% beet pulp (PWB), and 40% poplar sawdust, 40% cotton seed hull and 20% beet pulp (PCB). The increase in the sterilization temperature caused decrease in the pH of the substrate. The moisture content of PWB substrate increased by 1.8%, but that of PCB substrate decreased by 4.1 % after low temperature sterilization ($12hr\;at\;60^{\circ}C$). However, a little change in the sterilization at higher temperature ($6hr\;at\;100^{\circ}C\;and\;90min\;at\;121^{\circ}C$) did not alter the moisture content of both substrate appreciably. The duration of mycelial growth was longest and its density was lowest in low temperature sterilization ($12hr\;at\;60^{\circ}C$). The high pressure sterilization ($90min\;at\;121^{\circ}C$) of PCB substrate produced high yield (236.6 g/pot) and the highest biological efficiency (96.6%) for Chunchunutari-2-ho. On the contrary the high temperatures sterilization ($6hr\;at\;100^{\circ}C$) of PCB substrate resulted in the yield of 259.1 g/pot with the biological efficiency 94.9% for Suhannutari-2-ho.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.311-319
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• 2015

Near infrared (NIR) reflectance spectroscopy was employed to develop moisture content prediction model of pitch pine (Pinus rigida), red pine (Pinus densiflora), Korean pine (Pinus koraiensis), yellow poplar (Liriodendron tulipifera) wood below fiber saturation point. NIR reflectance spectra of specimens ranging from 1000 nm to 2400 nm were acquired after humidifying specimens to reach several equilibrium moisture contents. To determine the optimal moisture contents prediction model, 5 mathematical preprocessing methods (moving average (smoothing point: 3), baseline, standard normal variate (SNV), mean normalization, Savitzky-Golay $2^{nd}$ derivatives (polynomial order: 3, smoothing point: 11)) were applied to reflectance spectra of each specimen as 8 combinations. After finishing mathematical preprocessings, partial least squares (PLS) regression analysis was performed to each modified spectra. Consequently, the mathematical preprocessing methods deriving optimal moisture content prediction were 1) moving average/SNV for pitch pine and red pine, 2) moving average/SNV/Savitzky-golay $2^{nd}$ derivatives for Korean pine and yellow poplar. Every model contained three principal components.

• Journal of Korean Society of Forest Science
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• v.70 no.1
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• pp.72-76
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• 1985

Populus alba ${\times}$ P. glandulosa cuttings in nursery bed were inoculated with mycelium of ectomycorrhizal fungus, Pisolithus tinctorius (Pt) to evaluate effectiveness of the fungus in growth stimulation of poplar. Pt was cultured in 1l glass bottles with vermiculite-peatmoss mixture moistened with modified Melin-Norkrans' solution. The nursery bed was arranged for microplots of $1{\times}2m$ in size and fumigated with methyl bromide before inoculation and cutting placement. Fifty cuttings were placed in each microplot and two treatments (fumigation only and fumigation plus Pt inoculation) were replicated three times. At the end of the first growing season, inoculated plants grew 19% faster in height and produced 49% more dry weight (above-ground portion) than uninoculated plants. Survival rate of inoculated cuttings was also improved by 20% over that of uninoculated cuttings. Inoculated cuttings developed abundant fine root system with golden brown zigzag tips. In the middle of September a sporocarp of Pt was produced from an inoculated plot, suggesting successful establishment of mycorrhiza between poplar and Pt fungus.