• Landscaping Tree
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• s.129
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• pp.14-19
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• 2012

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.180-188
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• 2019

Auxin plays a crucial regulatory role in plant growth and development processes. Three major classes of auxin-responsive transcription factors controlled by the Auxin/indole-3-acetic acid (Aux/IAA), Gretchen Hagen 3 (GH3), and small auxin up RNA (SAUR) genes regulate auxin signaling. Aux/IAA, in particular, encodes short-lived nuclear proteins that accumulate rapidly in response to auxin signaling. In this study, we isolated a PagAux/IAA1 gene from poplar (Populus alba ${\times}$ P. glandulosa) and investigated its expression characteristics. The PagAux/IAA1 cDNA codes for putative 200 amino acids polypeptide containing four conserved domains and two nuclear localization signals (NLSs). Utilizing Southern blot analysis, we confirmed that a single copy of the PagAux/IAA1 gene was present in the poplar genome. The expression of this gene is specific to leaves and flowers of the poplar. PagAux/IAA1 expressed in the early exponential growth phase of cell-cultured in suspension. PagAux/IAA1 expression level reduced in drought and salt stress conditions, and the presence of plant hormones such as abscisic acid. However, expression enhanced in cold stress, cambial cell division, and presence of plant hormones such as gibberellic acid and jasmonic acid. Thus, these results suggest that PagAux/IAA1 participates in cold stress response as well as developmental processes in the poplar.

• Journal of the Korean Ceramic Society
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• v.47 no.4
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• pp.308-311
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• 2010

Porous SiC samples were prepared with three types of wood (poplar, pine, big cone pine) by simply embedding the wood charcoal in a powder mixture of Si and $SiO_2$ at 1600 and $1700^{\circ}C$. The basic engineering properties such as density, porosity, pore size and distribution, and strength were characterized. The samples showed full conversion to mostly $\beta$-SiC with good retention of the cellular structure of the original wood. More rigid SiC struts were developed for $1700^{\circ}C$. They showed similar bulk density ($0.5{\sim}0.6\;g/cm^3$) and porosity (81~84%) irrespective of the type of wood. The poplar sample showed three pore sizes (1, 8, $60\;{\mu}m$) with a main size of $60\;{\mu}m$. The pine sample showed a single pore size ($20\;{\mu}m$). The big cone pine sample showed two pore sizes (10, $80\;{\mu}m$) with a main size of $10\;{\mu}m$. The bend strength was 2.5 MPa for poplar, 5.7 MPa for pine, 2.8 MPa for big cone pine, indicating higher strength with pine.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.4
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• pp.171-175
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• 2011

This study was conducted to determine the susceptibility of 15 clones of native and foreign poplar species and their hybrids to Melampsora leaf rust and to select resistant clones at a nursery stool bed. Rust severities of individual trees were determined by estimating the percentage of infected leaves on the trees in addition to comparing the infected leaves with the infection diagrams. Three hybrids out of 15 clones were selected as resistant clones to the Melampsora leaf rust in Korea. Bong-wha 1 and Hyunsasi 3 belong to section Leuce, and Dorskamp belongs to section Aigeiros. Based on our results, we recommend Dorskamp as the best resistant clone to poplar leaf rust.

• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.404-404
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• 2024

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.696-702
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• 2009

Yellow poplar (Liriodendron tulipifera L.) is an insect-pollinated tree species with large, perfect flower, and its seed sets average only about 10 percent naturally. In its controlled pollination, pollination bags are usually taken to prevent unwanted pollination, but bagging is an expensive and time-consuming process. Therefore, this study was conducted to determine the need of pollination bag by estimating how much unintended pollination would occur when different cross methods were applied. Five different pollination methods were applied as follows: 1) natural open pollination (i.e. insect pollination) as a reference, 2) self-pollination; no removing reproductive organs with bagging, 3) open pollination; emasculated(removing sepal, petal and stamen) without bagging, 4) controlled pollination; emasculated with bagging and 5) controlled pollination; emasculated without bagging. Very low value of full seed rate (0.2%) was observed in method 3, it was suggested that removing stamen and petal restrict the activity of pollen vectors like bee. Difference in the full seed rate between method 4 and method 5 was not significant (27.9% versus 24.0%, respectively). Consequently, controlled pollination without bagging might be an alternative method for extensive breeding and mass production of seeds in yellow poplar.

• Journal of Plant Biotechnology
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• v.48 no.1
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• pp.34-43
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• 2021

Targeted genome editing using the CRISPR/Cas9 system is a ground-breaking technology that is being widely used to produce plants with useful traits. However, for woody plants, only a few successful attempts have been reported. These successes have used Agrobacterium-mediated transformation, which has been reported to be very efficient at producing genetically modified trees. Nonetheless, there are unresolved problems with plasmid sequences that remain in the plant genome. In this study, we demonstrated a DNA-free genome editing technique in which purified CRISPR/Cas9 ribonucleoproteins (RNPs) are delivered directly to the protoplasts of a hybrid poplar (Populus alba × Populus glandulosa). We designed three single-guide RNAs (sgRNAs) to target the stress-associated protein 1 gene (PagSAP1) in the hybrid poplar. Deep sequencing results showed that pre-assembled RNPs had a more efficient target mutagenesis insertion and deletion (indel) frequency than did non-assembled RNPs. Moreover, the RNP of sgRNA3 had a significantly higher editing efficacy than those of sgRNA1 and sgRNA2. Our results suggest that the CRISPR/Cas9 ribonucleoprotein-mediated transfection approach is useful for the production of transgene-free genome-edited tree plants.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.86-94
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• 2011

Pyrolytic lignin was obtained from biooil produced with yellow poplar wood. Fast pyrolysis was performed under various temperature ranges and residence times using fluidized bed type reactor. Several analytical methods were adopted to characterize the structure of pyrolytic lignin as well as the effect of pyrolysis temperature and residence time on the modification of the lignin. The yield of pyrolytic lignin increased as increasing pyrolysis temperature and decreasing residence time of pyrolysis products. The molecular weight of pyrolytic lignin determined by gel permeation chromatography (GPC) was approximately 1,200 mol/g, which was approximately a tenth of milled wood lignin (MWL) purified from the same woody biomass. Based on analytical data, demethoxylation and side chain cleavage reaction were dominantly occurred during fast pyrolysis.

• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.602-608
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• 2009

We investigated whether cadmium (Cd) toxicity affects phosphorus (P) concentration and growth of poplar, which might be related to the ectomycorrhizal associations. Populus ${\times}$tomentoglandulosa cuttings were treated with 0.1 mM and 0.4 mM $CdSO_4$ and inoculated with ectomycorrhizal fungus, Pisolithus tinctorius (Pt) and grown in autoclaved peat vermiculite mixture for five months under greenhouse conditions. Ectomycorrhizal plants showed significantly higher Cd concentration in leaves, stems and roots than in non-mycorrhizal plants. Likewise, P contents in leaves and roots of ectomycorrhizal plants were higher than those of non-mycorrhizal plants. Acid phosphatase activity in leaves of ectomycorrhizal plants, however, was significantly lower than that of non-mycorrhizal plants. 0.1 mM Cd significantly increased P content in leaves and stems of non-mycorrhizal plants. In spite of high P concentration, which is accompanied by lower acid phosphatase activity, plant growth was not improved by inoculation with P. tinctorius. Total plant dry weight was lower than the non-mycorrhizal counterpart. The results imply that this might be caused by the large amount of energy consumption to alleviate Cd toxicity resulted from high Cd accumulation in their tissues.

• Journal of Plant Biotechnology
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• v.42 no.2
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• pp.93-103
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• 2015

The isolation, cloning, and characterization of an R2R3-MYB transcription factor gene (MtMYB70) from the model legume Medicago truncatula is reported. MtMYB70 consists of a 768-bp coding sequence corresponding to 255 amino acids. Sequence alignment revealed that MtMYB70 cDNA contains conserved R2R3-type MYB domains with highly divergent C terminal regions. MtMYB70 was found to have relatively low sequence homology with known R2R3-MYB genes. Phylogenetic analysis placed the R2R3-MYB domain of MtMYB70 closest to PtMYB1, a known activator of lignin biosynthesis. Overexpression of MtMYB70 under the control of the 35S promoter in transgenic poplar did not cause a significant difference in total lignin content relative to the control, but glucan content was significantly increased in transgenic poplar. Therefore, MtMYB70 might have regulatory role in the biosynthesis of cell wall structural carbohydrates.