• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.296-302
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• 2005

We investigated changes in photosynthetic characteristics of P. davidiana in order to understand damage patterns to photosynthetic apparatus under drought stress. Root sprout saplings of P. davildiana were treated with $0\%,\;2\%,\;5\%,\;and\;10\%$ of 300ml polyethylene glycol (PEG) once a weer far one month. After one month, we measured photosynthetic parameters and analyzed the photochemical and $CO_2$ fixation systems. Photosynthetic rate, stomatal conductance, and respiration rate in the leaves of P. davildiana decreased according to increasing stress strength. In the photochemical system, quantum yield of PSII was reduced by the increment of PEG concentration, The decrease of apparent quantum yield was related to reduction of electron transport. Respiration rate decreased with an increase in PEG concentration, whereas photorespiration rate in the $CO_2$ fixation system increased. In conclusion, photosynthesis of P. davidiana responded sensitively under drought stress, and the sensitivity depended upon the strength of water stress. P. davidiana exhibited an increase of water use efficiency under water stress.

• Korean Journal of Plant Resources
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• v.21 no.3
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• pp.210-215
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• 2008

Gene-expression analysis is increasingly important in biological research, with real-time reverse PCR (RTPCR) becoming the method of choice for high-throughput and accurate expression profiling of selected genes. However, this technique requires important preliminary work for standardizing and optimizing the many parameters involved in the analysis. Plant stress studies are more and more based on gene expression. The analysis of gene expression requires sensitive and reproducible measurements for specific mRNA sequence. Several genes are regulated in response to abitoic stresses, such as salinity, and their gene products function in stress response and tolerance. The design of the primers and TaqMan probes for real-time PCR assays were carried out using the Primer $Express^{TM}$ software 3.0. The PCR efficiency was estimated through the linear regression of the dilution curve. To understand the expression pattern of various genes under salt stressed condition, we have developed a unique public resource of 9 stress-related genes in poplar. In this study, real-time RT-PCR was used to quantify the transcript level of 10 genes (9 stress-related genes and 1 house keeping gene) that could play a role in adaptation of Populus davidiana. Real-time RT-PCR analyses exhibited different expression ratios of related genes. The data obtained showed that determination of mRNA levels could constitute a new approach to study the stress response of P. davidiana after adaptation during growth in salinity condition.

• Journal of Korean Society of Forest Science
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• v.66 no.1
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• pp.74-78
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• 1984

The highest cutting ratio and the best growth performance of the P. alba, P. alba ${\times}$ P. glandulosa and P. glandulosa were at -0.05 bars of soil water potential (${\Psi}_s$). Their growth and rooting ability of cuttings were better in suitable soil moisture contents, 19.650, but were worse in low soil moisture contents, 11.41% and 16.66%, respectively. Specially, P. alba ${\times}$ P. glandulosa appeared hybrid vigor in high soil water potential (${\Psi}_s$= -0.05 bars) but not appeared it below ${\Psi}_s$ = -0.5 bars. It is believed that P. glandulosa is a natural hybrid between P. davidiana and P. alba in view of morphological characteristics. Aspen, normally, does not have the rooting ability of cuttings, however, P. glandulosa showed the rooting ability, though the ratio was low, 23%. It is estimated that this rooting ability was originated from P. alba. In addition, its growth rate was between P. alba and P. davidiana, and the sensitivity of water requirement for the growth was also really equal to P. alba. This facts prove P. glandulosa to be natural hybrid between P. alba and P. davidiana.

• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.513-523
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• 2009

Many species, cultivars, and hybrids in Populus have been introduced and developed by the scientists of Department of Forest Genetic Resources, Korea Forest Research Institute in Korea. P. alba ${\times}$ glandulosa, P. euramericana, P. nigra ${\times}$ maximowiczii, P. koreana ${\times}$ P. nigra var. italica, and P. davidiana have been studied from many aspects, i.e., genetics, breeding, physiology, propagation, silviculture, biomass production, biotechnology and phytoremediation. These precedent results will provide a sound basis for a newly-arising research on short-rotation coppice as one of renewable resources and phytoremediation plants. It was found that there were many promising varieties and clones for these purposes. However, minute analysis on specific gravity and caloric values for those plants should be followed under several silvicultural and rotational systems.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2005.09a
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• pp.133-136
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• 2005

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.40-56
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• 2023

Tree species within the Populus genus grow rapidly and have an excellent capacity to absorb carbon, conferring substantial ability to effective purify the environment. Poplar breeding can be achieved rapidly and efficiently if a genetic linkage map is constructed and quantitative trait loci (QTLs) are identified. Here, a high-density genetic linkage map was constructed for the control pollinated progeny using the genotyping-by-sequencing (GBS) technique, which is a next-generation sequencing method. A search was also performed for the genes associated with quantitative traits located in the genetic linkage map by examining the variables of height and diameter at root collar, and resilience to insect damage. The height and diameter at root collar were measured directly, while the ability to recover from insect damage was scored in a 4-year-old breeding population of aspen hybrids (Odae19 × Bonghyeon4 F1) established in the research forest of Seoul National University. After DNA extraction, paternity was confirmed using five microsatellite markers, and only the individuals for which paternity was confirmed were used for the analysis. The DNA was cut using restriction enzymes and the obtained DNA fragments were prepared using a GBS library and sequenced. The analyzed results were sorted using Populus trichocarpa as a reference genome. Overall, 58,040 aligned single-nucleotide polymorphism (SNP) markers were identified, 17,755 of which were used for mapping genetic linkages. The genetic linkage map was divided into 19 linkage groups, with a total length of 2,129.54 cM. The analysis failed to identify any growth-related QTLs, but a gene assumed to be related to recovery from insect damage was identified on linkage group (chromosome) 4 through genome-wide association study.

• Journal of Korean Society of Forest Science
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• v.83 no.2
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• pp.239-245
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• 1994

The broad sense heritability of height of clonal means was estimated from 18 clones out of 25 clones growing at four different sites, and it showed considerably high heritability of $H^2_{CM}=0.883$. Therefore if we select the best one clone(5% selection), the genetic gain of 35.3% which is equal to 1.02m in height is expected to attain. If we select the best two clones(10% selection), the genetic gain will be 25.6% which is equal to 0.74m in height. Because the trees are only 4-year-old, it is expected to show higher genetic gain than the current gain when the trees reach to the age of final selection.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.255-259
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• 1990

To investigate relative flammability in flaming combustion among 10 softwoods and 10 hardwoods, oxygen indices were determined for flat-grained sapwoods through Up and Down method following oxygen index test of ASTM D 2863-77. Oxygen index ranged from 21.0 for Pinus strobus to 28.2 for Larix gmelinii var. principis-ruprechtii in softwoods and from 20.7 for Populus davidiana to 27.6 for Quercus acntissima in hardwoods, which indicates Larix gmelinii var. principis-ruprechtii and Quercus acutissima being ranked first in inflammability and Pinus strobus and Populus davidiana being the least in fire resistance by softwood and hardwood because highly flammable materials are likely to have a low oxygen index.

• Journal of Forest and Environmental Science
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• v.15 no.1
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• pp.1-9
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• 1999

Noticing the intrinsic growing habit variations of hardwood species which is indigenous to the natural deciduous forest, eighteen tree species in overstory were selected for comparative evaluating tree form so as to develop the tree form index (TFI). Selected six tree form attributes were arbitrarily divided four assessment criteria and given appropriate scores. Eighteen tree species were undergone corresponding scores, converted to percentage base, and estimated TFI by the summation of the six scoring values. Cluster analysis was carried out to review which attribute would have been shared among species based on dissimilarity of scores for each pair of species in $18{\times}6$ data matrix. The result showed that Populus davidiana had the highest TFI value of 80.8 and Carpinus cordata had the lowest TFI va1ue of 46.3. The species which received more than 70 of TFI are Populus davidiana, Betula costata, Fraxinus mandshurica, and Ulmus davidiana var. japonica, characterized by the advantage of straight and longer bole, the narrower crown, and the thinner branch. On the contrary, such species as Sorbus alnifolia. Prunus sargentii, Acer mandshuricum, Juglans mandshurica, and Carpinus cordata received less than 60 of TFI, characterized by the disadvantage of the crooked or forked stem. the wider or deeper crown. and the thicker branch. In the dendrogram produced by cluster analysis, arbitrary value of Euclidean distance 10 divided eighteen species into four distinctive groups. and the typical characteristics of each group were discussed.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.450-457
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• 2020

Single pellet press technology allows for fast, low-cost, and small-scale tests to investigate pelletizing characteristics. We estimated proper compression ratios for five Korean domestic wood species through predicted relationships between pelletizing pressure P_x and compression ratio based on experimental data obtained from a single pellet press unit. The pressures required to obtain a 6-mm-diam pellet of density 1200 kg/㎥ were estimated as 111 MPa for Populus davidiana, 133 MPa for Robinia pseudoacacia, 136 MPa for Quercus mongolica, 97 MPa for Pinus densiflora, and 127 MPa for Pinus rigida. On the basis of these pressures, we estimated proper compression ratios to be within the range 7.676-8.410 for these species, and we found the compression ratios needed for hardwood species to be somewhat higher than those needed for softwood species to obtain the pellet density of 1200 kg/㎥.