• Journal of Plant Biotechnology
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• v.35 no.3
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• pp.229-234
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• 2008

An efficient micropropagation was established by using axillary bud explants from two-year-old tree(Echinosphorea koreensis Nakai), which has been known as a rare and endangered species. Among various basal media tested, DKW medium was shown to be the best for axillary shoot elongation. The addition of both BA and TDZ to the medium induced 6 to 10 shoots per explant during eight weeks of culture, without showing any abnormal morphology at the shoot proliferation stage. However, high concentration of TDZ(>0.05 mg/L) appeared to cause hyperhydration on either leaf or shoot at the later developmental stage. Approximately 20% of shoots produced roots by the addition of 1.0 mg/L NAA but not by IBA($0.2{\sim}1.0$ mg/L). Ex vitro micro-cuttings were better source for root induction; up to 58.6% of the micro-cuttings rooted when 100 mg/L IBA was applied to the soil(vermiculite). More than 90% of plantlets with roots were successfully acclimatized and grew normally in the field. Therefore, we suggest that this endangered tree species can be effectively micropropagated by axillary bud culture system developed in this study.

• Journal of Korean Society of Forest Science
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• v.30 no.1
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• pp.50-60
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• 1976

For finding out the proper method of developing Buxus koreana var. insularis, this study was carried out in Pokil-Do, Wan-Do, Chonnam, in 1975. The ecology, morphology and characteristics of the plant were mainly investigated and analyzed. The results are summarized as follows; 1. The small islands of the southern sea of Korea; Pokil-Do, Chin-Do and So-Huk-San-Do, turn out to be the site of the natural communities of B. koreana var. insularis. 2. The growth of the plant is fairly good in the acid soil of these islands. 3. This vegetation of composed as the three-layered communities, these communities consit of Camellia, Buxus and Cares. 4. The plant is a board leaved evergreen shrub that is tolerant to shade and native to the temperate zone. 5. The size of the leaves, fruits and seeds is slightly larger than those of B. koreans. 6. As fruiting and germination of the seeds are favorable. it is easy for us to make a number of seedlings. 7. The proper times for sowing and harvesting the seeds are around the middle of July and August, respectively. 8. The seedlings is difficult to grow in the naked ground because the germinated seeds are seriously damaged by frost. 9. The plant growth per annum is about 8 to 10cm in height, 1.5mm in diameter. It is graceful looking as the branches and leaves as of the dense foliage type 10. It is possible to develop the plant in many ways, such as; ornamental plant, bee plant, sculptural and industrial materials.

• The Korean Journal of Mycology
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• v.30 no.1
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• pp.44-49
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• 2002

The study was conducted to isolate and identify insecticidal bacteria for biological control of larvae of mushroom fly, Lycoriella mali, which is one of serious pests to oyster mushrooms during its cultivation period. Among eight bacteria isolated from the soil in the oyster mushroom beds and the dead body of L. mali, two bacteria, Bti-D and Bti-U showed more toxicity with mortality rate than other six-bacteria isolates. The two bacteria showed more toxicity in three instar of the period of development of the mushroom fly than in other instar. Symptoms of the larvae of L. mali infected by the two bacteria developed as follows: at the early infection, the front middle gut changed color to light brown, the middle gut to brown, whole body to black brown, and eventually, the fly died. For the identification of these isolates, cultural and biochemical characteristics by Bergey's manual and Biolog system, cell morphology by TEM, endospore and endotoxin by phase-contrast microscope, and test using 33H antisera were examined. According to the results, these two isolates, Bti-D and Bti-U were identified as Bacillus thuringiensis subsp. israelensis respectively.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1286-1298
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• 2005

The genus Paenibacillus is a new group of bacilli separated from the genus Bacillus, and most of species have been isolated from soil. In the present study, we collected 450 spore-forming bacilli from the roots of winter crops, such as barley, wheat, onion, green onion, and Chinese cabbage, which were cultivated in the southern part of Korea. Among these 450 isolates, 104 Paenibacillus-like isolates were selected, based on their colony shape, odor, color, and endospore morphology, and 41 isolates were then finally identified as Paenibacillus spp. by 16S rDNA sequencing. Among the 41 Paenibacillus isolates, 23 were classified as P. polymyxa, a type species of the genus Paenibacillus, based on comparison of the 16S rDNA sequences with those of 32 type strains of the genus Paenibacillus from the GenBank database. Thirty-five isolates among the 41 Paenibacillus isolates exhibited antagonistic activity towards plant fungal and bacterial pathogens, whereas 24 isolates had a significant growth-enhancing effect on cucumber seedlings, when applied to the seeds. An assessment of the root-colonization capacity under gnotobiotic conditions revealed that all 41 isolates were able to colonize cucumber roots without any significant difference. Twenty-one of the Paenibacillus isolates were shown to contain the nifH gene, which is an indicator of $N_{2}$ fixation. However, the other 20 isolates, including the reference strain E681, did not incorporate the nifH gene. To investigate the diversity of the isolates, a BOX-PCR was performed, and the resulting electrophoresis patterns allowed the 41 Paenibacillus isolates to be divided into three groups (Groups A, B, and C). One group included Paenibacillus strains isolated mainly from barley or wheat, whereas the other two groups contained strains isolated from diverse plant samples. Accordingly, the present results showed that the Paenibacillus isolates collected from the rhizosphere of winter crops were diverse in their biological and genetic characteristics, and they are good candidates for further application studies.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.300-307
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• 1995

This study was carried out to investigate the life cycle of Cephonodes hylas (Linne), that is damaging to Gardenia jasminoides Ellis in the seedbed at Namhae during 1984 and 1985. Results are summarized as follows. The eggs were laid in mass on the leaf surface of the host plants. The oviposition period lasts for 26 days after late-May. The average number of eggs and average hatching rate were 20.36 and 97.61% , respectively. It takes 14-16 days until hatching. The egg shape was oval which its size was 1.01 mm in diameter and 1.48 mm in length. The body length of each larval instar from the 1st to the 5th were $3.52\pm$1.01, $6.46\pm$0.45, $13.19\pm$4.27, $24.08\pm$2.22 and $43.71\pm$5.62 mm, respectively. The average weight of each larval instar were $13.34\pm$2.41, $29.83\pm$6.88, $76.64\pm$31.31, $292.09\pm$107.70 and 2,$144.84\pm$760.70 mm, respectively. The larval period was observed from July to October, and total duration of larval stage was 116 days in which duration of each larval instar from the 1st to the 5th were 12, 36, 32, 16 and 20 days, respectively. During larval stage, a larvae feed on 17~18 seedlings. The 5th instar larvae built its place in soil for overwinter and became pupa. The body length of pupa was 33.6 mm and average weight was 2,032 mg Adult was emerged from overwintened pupa from mid through late-May in the followings year. The sex ratio of female was 42.82% and the color ratio of brown was 89.93%.

• The Korean Journal of Mycology
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• v.41 no.2
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• pp.112-117
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• 2013

Phytophthora capsici is one of major limiting factors in production of pepper and other important crops worldwide by causing foliage blight and rot on fruit and root. Increased demand for the replacement of fungicides has led to searching a promising strategy to control the fungal diseases. To meet eco-friendly agriculture practice, we isolated microorganisms and assessed their beneficial effects on plant health and disease control efficacy. A total of 360 bacterial strains were isolated from rhizosphere soil of healthy pepper plants, and categorized to 5 representative isolates based on colony morphology. Among the 5 bacterial strains (GJ-1, GJ-4, GJ-5, GJ-11, GJ-12), three bacterial strains (GJ-1, GJ-11, GJ-12) presented antifungal activity against P. capsici in an fungal inhibition assay. In phosphate solubilization and siderophore production, the strain GJ-1 was more effective than others. The strain GJ-1 was identified as Bacillus sp. using 16S rDNA analysis. Bacillus sp. GJ-1 was also found to be effective in inhibiting other plant pathogenic fungi, including Rhizoctonia solani, Pythium ultimum and Fusarium solani. Therefore, the Bacillus sp. GJ-1 can serve as a biological control agent against fungal plant pathogens.

• Journal of Korean Society of Forest Science
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• v.94 no.1 s.158
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• pp.16-20
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• 2005

Tricholoma matsutake ectomycorrhizas are unique in their morphology: not bifurcated broom shaped roots with not easily wettable brilliant and profuse white hyphae. To understand these characteristics the ectomycorrhizas were investigated with electron microscopy. T. matsutake ectomycorrhiza have thin mantle and typical Hartig net development in the epidermis and cortex, but no fungal mantle on the root apex. There were no penetrating hyphae inside of the cells of either epidermis, cortex or stele. Inside of the walls of epidermis and cortex cells are lined with ca. $2{\mu}m$ hemispherical amyloplasts. The brilliant hyphal surface was covered with various fine amorphous granules. The hyphal cell wall was thin membrane less than $0.3{\mu}m$ thick. There is no clamp connection on the hyphae. This thin membraneous cell wall with high elasticity can be related to survival strategy of the species without plasmolysis under frequent soil water stress environment. And the coarse hyphal surface with some water repellency can control sudden inrush of water of the hyphae with an extremely low osmotic potential. It is concluded that no mantle on the tip can induce mycorrhizas not bifurcated and that finely coarse surface of T. matsutake hyphae can make the hyphae brilliantly white but less wetted.

• Journal of Life Science
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• v.25 no.12
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• pp.1458-1469
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• 2015

Many organic solvent-tolerant bacteria have been isolated from all environments such as soil, waste-water, even deep sea after first isolation report of organic solvent-tolerant bacterium. Most organic solvent- tolerant isolates have been determined to be Gram-negative bacteria, because Gram-negative bacteria have inherent tolerance property toward hostile organic solvents more than Gram-positive bacteria. The mechanisms of organic solvent tolerance have been elucidated extensively using mainly organic solvent-tolerant Gram-negative bacteria. The solvent-tolerance mechanisms in Gram-positive bacteria can be found in comparatively recent research. Organic solvents exhibited different toxicity depending on the solvent, and the tolerance levels of organic solvent-tolerant bacteria toward organic solvents were also highly changeable among species and strains. Therefore, organic solvent-tolerant bacteria could coped with solvent toxicity and adapted to solvent stress through the multifactorial and multigenic adaptative strategies. They could be survived even in the hyper concentrations of organic solvents by mechanisms which include: changes in cell morphology and cell behaviour, cell surface modifications, cell membrane adaptations, solvent excretion pumps, chaperones and anti-oxidative response. The aim of this work is to review the representative solvent tolerant bacteria and the adaptative and tolerance strategies toward organic solvents in organic solvent-tolerant bacteria, and their potential industrial and environmental impact.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.480-488
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• 1994

Low seedling growth rates of white clover (Trifolium repens L.) have been limited its good establishment to pastures. The experiment was done to determine the effect of removal of cotyledon and unifoliolate on the growth and morphological characters of contrasting white clover cultivars for 8 weeks after the treatment. Individual plants of cv. Regal (large leaf), Louisiana S-l (medium-large leaf), Grasslands Huia (medium-small leaf) and Aberystwyth S184 (small leaf) were grown in 10cm plastic pot containing a 2:1:1 soil:sand:peat moss mixture until the cotyledon or unifoliolate stage and then removed one (C1) or two cotyledons (C2) at cotyledon stage, and unifoliolate only (U), unifoliolate and one cotyledon (DC1) or unifoliolate and two cotyledons (DC2) at the unifoliolate stage. To measure the removal effect on biomass and morphological characters (leaf area, petiole and stolon lengths, growing tips and leaves), plants were sampled 4, 6 and 8 weeks after the treatment. Intact plants had greater biomass and morphological characters than removal-treated ones, Removal treatments at cotyledon stage, C1 and C2, were decreased more biomass and morphological characters than removal ones at unifoliolate stage while the severer cotyledon removal, the more reduction. Stolon length per plant and petiole length markedly inclined 6 weeks after the treatments although biomass and the other characters continuously did. Relatively large-leaved cultivar had more biomass, leaf area per plant and longer petiole than the other(s) but the reverse results were true in stolon length, growing tips and no. of leaves per plant. Biomass was linearly increased with increased leaf area but the earlier and severer removal, the less slope. The severer damage of cotyledon and unifoliolate had detrimental effects on the growth and aftermath establishment of white clover

• Research in Plant Disease
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• v.11 no.2
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• pp.152-157
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• 2005

In a course of searching for biofungicide to control crisphead lettuce bottom rot caused by Rhizoctonia solani, we have isolated an antagonistic bacterium from lettuce rhisophere soil. A total of 702 bacterial isolates were isolated and tested for in vitro growth inhibition of R. solani. Seven strains appeared to have strong antagonistic effect against R. solani in in vitro growth inhibition assay. In the pot experiments, a strain BW-13 showed the most potent disease control effect on the both lettuce seedlings and adults plants. Therefore, the BW-13 was selected as a biocotrol candidate against crisphead lettuce bottom rot. Based on its morphology, physiological characteristics, and 165 rRNA gene analysis, the BW-13 was finally identified as Stenotrophomonas maltophilia. This study indicated that S. maltophilia BW-13 could be used as a biocontrol agent to control crisphead lettuce bottom rot.