• Korean Journal of Soil Science and Fertilizer
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• v.34 no.6
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• pp.373-379
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• 2001

The weathering rates and change of chemical composition of 6 residual Entisols derived from granite, granite-gneiss, limestone, sandstone, shale, amd basalt in Korea were studied. The chemical composition of each profile with parent rocks were determined using XRF with the physico-chemical properties and the morphology of soils. In the A horizons of all the soils except Euiseong series, the content of clay, organic matter and cation exchange capacity(CEC) showed higher than those of C horizon, but bulk density and pH showed lower than C horizon. Clay content in the soil from sandstone was decrease with soil depth, which may caused by the elluriation. In total element analysis. $SiO_2$ was high in the soil from granite. granite-gneiss, sandstone and compare with basalt and limestone. $Fe_2O_3$ and MgO was high in the soil from basalt, limestone and shale compare with granite. granite-gneiss and sandstone. And ignition loss was particularly high in the soil from basalt and limestone. The rate of element loss was higher in base cations(Ca, K, Mg, Na) than Si, Al, Fe in the soils. The concentrations of $TiO_2$ in the A horizon compare with that of the C horizon was due to resulting from losses of other less stable elements existed. Considering with relative rate of each elements in soils, $SiO_2$ and $Al_2O_3$ which originated from sandstone and granite, granite-gneiss, sandstone, shale, and basalt were lost higher than those from lime tone, but loss of basic cations were more in the soil from limestone which may be rapid weathering of calcite. The magnitude of losses of the overall elements were increased in the order of the soils from sandstone and granite ${\gg}$ limestone and shale) granite-gneiss and basalt.

• Animal Systematics, Evolution and Diversity
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• v.20 no.2
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• pp.171-178
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• 2004

Two oxytrichid ciliates collected from the two habitats (soil under pine forest near beach and sewage treatment plant) in Korea were identified as Oxytricha balladyna Song and Wilbert, 1989 and O. longa Gelei and Szabados, 1950. These species are reported in this paper for the first time from Korea. The description was based on the observation of living specimens and protargol impregnated specimens. Diagnostic characteristics for each species are as follows. O. balladyna: one micronucleus located between two macronuclei, five transverse cirri, three caudal cirri, five rows of dorsal kinety, no granule in cytoplasm. O. longa: each micronucleus closely located near two macronuclei, three postoral ventral cirri lying in a straight line and positioned far away from transverse cirri, four transverse cirri, two caudal cirri, four rows of dorsal kinety, yellow-green granules scattered on cytoplasm.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.4
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• pp.394-400
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• 1992

In the isolated 280 Actinomycetes strains, 12 groups of Streptomyces were 87.2% and 3groups of Non-Streptomyces were 12.8%, respectively. Streptomyces with sporophore of the spiral chain form reached to 80% of all the Streptomyces isolates. Surface morphology of spores have been determined with the electron microscope ; two groups have a spiny surface, 10 groups have a smooth surface. Isolated Actinomyceles groups were indentified as Streptomycetes groups and Non-Streptomyces groups. Actinomycetes isolates were selected as the strains having predominant antibacterial activities against the microorganisms among the 15 groups which has antibacterial activities. Selected Actinomycetes isolates showed high antibiotic sensitivity of S-9 strain(8.46 r/ml), S-6 strain(6.23 r/ml), S-2 strain(7.24 r/ml) against Pseudomonas aeruginosa (ATCC 27857), Escherichia coli (ATCC 25922) and Staphylococcus aureus(ATCC 6538).

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.393-400
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• 2016

Fusarium graminearum is the main cause of substantial economic loss in wheat production. The aim of this study is to investigate biocontrol potential of Lysobacter antibioticus HS124 against F. graminearum and to purify an antifungal compound. In preliminary study, n-butanol crude extract revealed destructive alterations in the hyphal morphology of F. graminearum and almost degraded with $1,000{\mu}g\;mL^{-1}$ concentration. For further study, the antifungal compound extracted from the n-butanol crude extract of L. antibioticus HS124 was identified as N-Butyl-tetrahydro-5-oxofuran-2-carboxamide ($C_9H_{16}NO_3$) using NMR ($^1H-NMR$, $^{13}C-NMR$, $^1H-^1H\;COSY$, HMBC, and HMQC), and HR-ESI-MS analysis. To our knowledge, N-Butyl-tetrahydro-5-oxofuran-2-carboxamide may be a novel compound with molecular weight of 186.1130. The minimum inhibitory concentration value of antifungal compound was $62.5{\mu}g\;mL^{-1}$ against F. graminearum. In an in vivo pot experiment, crown rot disease from F. graminearum was inhibited when wheat seeds were treated with both HS124 culture and F. graminearum. Growth of wheat seedling was enhanced by treatment of HS124 compared to control. Our results suggest that L. antibioticus HS124 characterized in this study could be successfully used to control F. graminearum and could be used as an alternative to chemical fungicides in modern agriculture.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.239-248
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• 2009

In this investigation, we observed surface morphology and porosity of a macroporous adsorbent made of Na-bentonite and Ca-bentonite as structure formation materials and grounded waste paper as macropore forming material for the development of a permeable reactive barrier to remove heavy metals in groundwater. Therefore, we selected minerals having higher cation exchange capacity among 2:1 clay minerals and other industrial minerals because sintering can significantly influence cation exchange capacity, resulting in drastic decrease in removal of heavy metals. The results showed that the increasing sintering temperature drastically decreased CEC by less than 10 % of the indigenous CEC carried by the selected minerals. One axial compressibility test results showed that the highest value was obtained from 5% newspaper waste pulp for both structure formation materials of Na-bentonite and Ca-bentonite although there were not much difference in bulk density among treatments. The pore formation influenced by sintering temperature and period contributes removal of heavy metals passing through the sintered macroporous media having different water retention capacity.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.328-328
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• 2017

Drought is a major limiting factor that reduces rice production and occurs often especially under recent climate change. Plants have the ability to alter their developmental morphology in response to changing environment, which is known as phenotypic plasticity. In our previous studies, we found that one chromosome segment substitution line (CSSL50 derived from Nipponbare and Kasalath crosses) showed no differences in shoot and root growth as compared with the recurrent genotype, Nipponbare under non-stress condition but showed greater growth responses compared with Nipponbare under mild drought stress condition. We hypothesized that reducing root respiration as metabolic cost, which may be largely a consequence of aerenchyma formation would be one of the key mechanisms for root plasticity expression. This study aimed to evaluate the root respiration and aerenchyma formation under various soil moisture conditions among genotypes with different root plasticity. CSSL50 together with Nipponbare and Kasalath were grown under waterlogged conditions (Control) and mild drought stress conditions (20% of soil moisture content) in a plastic pot ($11cm{\times}14cm$, ${\varphi}{\times}H$) and PVC tube ($3cm{\times}30cm$, ${\varphi}{\times}H$). Root respiration rate was measured with infrared gas analyzer (IRGA, GMP343, Vaisala, Finland) with a closed static chamber system. There was no significant difference between genotypes in control for shoot and root growth as well as root respiration rate. In contrast, all the genotypes increased their root respiration rates in response to mild drought stress. However, CSSL50 showed lower root respiration rate than Nipponbare, which was associated by higher root aerenchyma formation that was estimated based on internal gas space (porosity) under mild drought stress conditions. Furthermore, there were significant negative correlations between root length and root respiration rate. These results imply that reducing the metabolic cost (= root respiration rate) is a key mechanism for root plasticity expression, which CSSL50 showed under mild drought.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.550-557
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• 2014

Heloniopsis koreana and Heloniopsis tubiflora (Melanthiaceae) are endemic herbaceous species of the Korean Peninsula. The Melanthiaceae family has been described as having seeds with small, underdeveloped embryos at the time of dispersal, and morphological (MD) or morphophysiological dormancy (MPD). However, there are few reports on embryo growth, morphology, and seed germination in Heloniopsis species. The aims of this study were to investigate embryo growth and seed dormancy, and to determine the type of dormancy exhibited by these species. The effects of incubation temperatures, light conditions, and gibberellic acid ($GA_3$) on dormancy break and seed germination were tested. Freshly matured seeds of the two species had small embryos that occupied about 9-11% of the length of the endosperm, and which increased by more than 300% in length before radicle emergence, indicating that the embryos are underdeveloped at the time of dispersal. Embryos in the seeds grew under warm temperature regimes (between $25/15^{\circ}C$ and $30/20^{\circ}C$). $GA_3$ application (tested only in the light) overcame seed dormancy and promoted germination. Approximately 30% of the seeds of H. koreana and approximately 40% of the seeds of H. tubiflora germinated in suitable environmental conditions (light and temperature) within 4 weeks. Therefore, 30-40% of the seeds of the two species exhibited MD, and the rest of the seeds had non-deep simple MPD. Light was found to be one of the critical factors for germination because no seed of either of the two Heloniopsis species germinated under constant dark conditions, and thus, these species have the potential to form a persistent soil seed bank. Understanding these germination requirements will help in development of effective strategies to increase the establishment of seedlings in their native habitat.

• KSBB Journal
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• v.7 no.3
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• pp.191-200
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• 1992

Several strains of Agrobacterium tumefaciens were isolated from soil in the Taegu area and characterized to develop some useful vector systems for higher plant genetic engineering. The selected colonies had a unique form, and strains from the colonies were capable of tumor formation on the sunflower leaf surface. They had a large plasmid. The restriction analysis showed that they were another kinds of Ti plasmic compared with C58 and Ach5. The isolated strains were identified as the nopaline type and also as biovar 1 A. tumefaciens, according to their tumor morphology, blophyslcal and biochemical characteristics. One of the isolated strains, AK204 was transformed with binary vector (pGA642), having selectable marker (Kmr, Tcr). Furthermore, maize tissue cells were transformed by cocultivation with AK204/pGA642, and the transformants were selected on the selective medium and identified using PAGE patterns of their soluble proteins.

• Journal of Species Research
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• v.4 no.2
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• pp.97-108
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• 2015

As a subset study to discover indigenous prokaryotic species in Korea, a total of 29 bacterial strains assigned to the classes Alphaproteobacteria were isolated from various environmental samples collected from plant root, ginseng soil, forest soil, marsh, mud flat, freshwater and seawater. From the high 16S rRNA gene sequence similarity (>99.1%) and formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to each independent and predefined bacterial species. There is no official report that these 29 species included in Alphaproteobacteria is have been described in Korea; therefore 14 species of 9 genera in the order Rhizobiales, 7 species of 6 genera in the order Sphingomonadales and 4 species of 2 genera in the order Caulobacterales and 3 species in the order Rhodobacterales and 1 species in the order Rhodospirillales found in Korea. Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source, and strain IDs are also described in the species description section.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.193-199
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• 2006

Halotolerant spore-forming Gram-positive bacteria were isolated from the root, rhizosphere, and non-rhizosphere soil of Blutaparon portulacoides. The different isolates were characterized genetically using an amplified ribosomal DNA restriction analysis (ARDRA), and phenotypically based on their colonial morphology, physiology, and nutritional requirements. Three different 16S rRNA gene-based genotypes were observed at a 100% similarity using the enzymes HinfI, MspI, and RsaI, and the phenotypic results also followed the ARDRA groupings. Selected strains, representing the different ARDRA groups, were analyzed by 16S rDNA sequencing, and members of the genera Halobaeillus, Virgibacillus, and Oceanobacillus were found. Two isolates showed low 16S rDNA sequence similarities with the closest related species of Halobacillus, indicating the presence of new species among the isolates. The majority of the strains isolated in this study seemed to belong to the species O. iheyensis and were compared using an AP-PCR to determine whether they had a clonal origin or not. Different patterns allowed the grouping of the strains according to Pearson's coefficient, and the resulting dendrogram revealed the formation of two main clusters, denoted as A and B. All the strains isolated from the soil were grouped into cluster A, whereas cluster B was exclusively composed of the strains associated with the B. portulacoides roots. This is the first report on the isolation and characterization of halotolerant spore-forming Gram-positive bacteria that coexist with B. portulacoides. As such, these new strains may be a potential source for the discovery of bioactive compounds with industrial value.