• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.235-244
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• 2004

In this study, we compared the levels of methylotrophic bacterial community diversity in the leaf samples of 19 rice cultivars collected from three regions of Korea. Nineteen pink pigmented isolates showing characteristic growth on methanol were obtained. Physiological and biochemical characters of each isolate were examined according to methods described in Bergey's Manual of Systematic Bacteriology. When phylotypes were defined by performing numerical analysis of 37 characteristics, four distinct clusters were formed. The two reference strains, Methylobacterium extorquens AM1 and Methylobacterium fujisawaense KACC10744 were found to group under cluster IV and cluster III respectively. Cluster I diverged on the basis of nitrate reduction and four isolates showed tolerance upto 0.5 M NaCl concentrations. Two strains in cluster I and III were found to possess methane utilizing properties. Most of the isolates in all the four clusters utilized monosaccharides, disaccharide and polyols as carbon source. When the isolates were subjected for indole-3-acetic acid (IAA) analysis in the presence of L-tryptophan, only 8 isolates exhibited IAA production. In addition, the nitrogen source in the medium was found to influence the IAA production. Addition of $(NH_4)_2SO_4$ in the medium led to a 2 to 30 fold increase in the indole synthesis. However, $KNO_3$, $NH_4NO_3$ and $NH_4Cl$ substitution did not significantly stimulate the synthesis of IAA in the growth medium. Result of gnotobiotic root elongation assay significantly increased roots and shoots lengths, and number of lateral roots, which is mediated by IAA production in the culture medium. The rice seedlings primary roots from seeds treated with methylotrophic isolates were on average 27 to 56% longer than the roots from seeds treated with the uninoculated seeds. In addition, application of different high concentrations of authentic IAA ($400g\;mL^{-1}$) to roots of rice seedlings inhibited root growth. However, the IAA concentration from 10 to $200g\;mL^{-1}$, IAA promoted root growth of rice seedlings. These results suggest that bacterial IAA plays a major role in the development of the host plant root system.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.84-95
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• 2013

Recently, to prevent damage to the landscape, outstanding landscape areas have been designated in advance. In particular, as a fundamental way to evaluate landscape elements, landscape diversity is an important criterion to assess an area with a high conservative value. Therefore, the purpose of this study is to develop a quantitative evaluation model of landscape diversity based on landscape elements and to verify the model by applying it to the study sites. The assessment indicators derived from the literature analysis are topography, vegetation, land-use pattern, and unusual landscape. Topography diversity is subdivided into land undulation and land-form. Vegetation diversity is subdivided into plant community diversity and stratification diversity. To quantitatively analyse each indicator's diversity, SHDI was selected as the central metric. All of the quantitative measures were implemented by using the statistical tool, FRAGSTATS. Through the process of each indicator's standardization and summary, the final landscape diversity index was calculated. The results of the study are significant as it was the initial study of landscape diversity evaluation to seek applicability. However, the results of the Landscape Diversity Evaluation Model in this study based on 4 indicators synthetically demonstrate that more than one or two outstanding indicators can be underrated. Therefore, each 4 assessment indicator results should be considered individually. Furthermore, using the maximum value for each indicator's standardization reflects that it is necessary to analyse various examples to obtain higher objectivity later.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.1
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• pp.31-36
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• 1982

Sugars and nitrogen contents and physico-chemical properties of ethanol extracts of fresh, dried, and tail ginsengs with different concentrations of the solvent were investigated. The transmittance at 550nm of fresh, dried and tail ginseng extracts (1% D.Wsoln) respectively, and all the extracts were slightly viscous-sticky, brown and pH of 4.8-6.2 Total sugars, sucrose and starch contents of the extracts were decreased with increasing of enthanol concentration as a solvent. Total sugar content of the extracts were decreased in the order of dried, tail and fresh ginseng and sucrose content were decreased in the order of fresh, driedcand tail ginsengs and starch content were decreased in the order of tail, dried and fresh ginsengs. The reducing sugar contents of the extracts were 4.9-3.8 %, 8.6-12.8 % and 7.6-9.1% in fresh, dried and tail ginsengs, respectively. Total nitrogen contents of the extracts were 2.3-4.6% in average and decreased in the order of dried, fresh and tail ginsengs.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.86-108
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• 2017

The nationwide weed survey was conducted in arable land, paddy field, upland, orchard and pasture, over whole country of Korea during 3 years from 2013 to 2015. Also, these survey were conducted in order to determine a change of weed community and to identify a major dominant weed species, and problem weeds. Weeds of arable land were composed of 619 species belonging to 81 families. Weeds occurred in paddy field were 90 species belonging to 28 families, upland weeds were 375 species of 50 families, orchard weeds were 492 species of 63 families and pasture weeds 275 species of 52 families. Among total 81 families, the Asteraceae (15.5%) was the biggest family, followed by Poaceae (13.1%), Fabaceae (5.5%), Cyperaceae (5.2%), Polygonaceae (6.3%), respectively. And these weed species were composed of annual weeds of 209 species (33.8%), winter annual of 102 species (16.4%) and perennial weeds of 308 species (49.8%). Exotic weeds naturalized in Korea were investigated as 166 species. Weed flora in Korean cultivation area have been increased as much as 13 families and 186 species for 10 years compared to 2000~2004 weed survey result of 68 families and 433 species. The increment could be resulted from the change of weed population such as increase of the herbicide-resistant and the difference of investigation method.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.1 no.1
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• pp.11-23
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• 2003

A study on the electrolytic dissolution of SUS-304 and Inconel-600 specimen was carried out in neutral salt electrolyte to evaluate the applicability of electrochemical decontamination process for recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds generated by dismantling a retired uranium conversion plant in Korea. Although the best electrolytic dissolution performance for the specimens was observed in a Na2s04 electrolyte, a NaNO$_3$ neutral salt electrolyte, in which about 30% for SUS-304 and the same for Inconel-600 in the weight loss was shown in comparison with that in a Na$_2$SO$_4$ solution, was selected as an electrolyte for the electrochemical decontamination of metallic wastes with the consideration on the surface of system components contacted with nitric acid and the compatibility with lagoon wastes generated during the facility operation. The effects of current density, electrolytic dissolution time, and concentration of NaNO$_3$ on the electrolytic dissolution of the specimens were investigated. On the basis of the results obtained through the basic inactive experiments, electrochemical decontamination tests using the specimens contaminated with uranium compounds such as UO$_2$, AUC (ammonium uranyl carbonate) and ADU (ammonium diuranate) taken from an uranium conversion facility were performed in 1M NaNO$_3$ solution with the current density or In mA/$\textrm{cm}^2$. it was verified that the electrochemical decontamination of the metallic wastes contaminated uranium compounds was quite successful in a NaNO$_3$ neutral salt electrolyte by reducing $\alpha$ and $\beta$ radioactivities below the level of self disposal within 10 minutes regardless of the type of contaminants and the degree of contamination.

• Korean Journal of Organic Agriculture
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• v.19 no.1
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• pp.65-82
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• 2011

In order to evaluate the weed suppressing effect of Solanum viarum Dunal. In this study species diversity in patch of S. viarum and allelopathic effects of the aqueous extracts on S. viarum were investigated. Number of species and species diversity in site close to patch of S. viarum were decreased gradually 1site ($7.7{\pm}2.0,\;1.5{\pm}0.2$), 2site ($5.3{\pm}1.2,\;1.2{\pm}0.2$) and 3site ($4.0{\pm}1.7,\;0.9{\pm}0.1$). And total phenolic compounds of soil in survey area were increased gradually site1 ($0.16{\pm}0.01mg\;g^{-1}$), site2 ($0.17{\pm}0.01mg\;g^{-1}$) and site3 ($0.22{\pm}0.02mg\;g^{-1}$). So the number of species and species diversity (r=-0.692, P<0.05) were negatively correlated with increased total phenolic compounds of soil in the survey area. The relative germination ratio, the mean germination time, the relative elongation ratio, the fresh weight and the dry weight of receptor plants are generally getting decreased while the concentration of the aqueous extracts from S. viarum escalate. But every ratio was various depending on the growing regions, the kind of receptor plants and the treatment of the aqueous extracts. Especially, the radicle by injection of the aqueous extracts concentration of S. viarum was influenced more than the shoot on the same condition. The total phenolic compounds on region of S. viarum was gradually increased in stems (fresh $0.56{\pm}0.02mg\;g^{-1}$, dry $1.58{\pm}0.08mg\;g^{-1}$), roots (fresh $1.77{\pm}0.07mg\;g^{-1}$, dry $2.64{\pm}0.06mg\;g^{-1}$), leaves (fresh $6.01{\pm}0.14mg\;g^{-1}$, dry $7.04{\pm}0.29mg\;g^{-1}$), seeds (fresh $6.21{\pm}0.17mg\;g^{-1}$, dry $9.08{\pm}0.73mg\;g^{-1}$) in order. On the contrary, the negative correlation on germination and growth of receptor plants was shown by total phenolic compounds on the each parts of S. viarum. We think that the aqueous extracts of S. viarum showed allelopathic effects on other plants. Therefore, S. viarum holds the higher competitiveness in plant community in Jeju Island and makes possibility of application as natural herbicide.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.559-575
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• 2012

This study, targeting Namhan Mountain Fortress which was designated as a No. 57 national historic site and placed on the World Heritage Tentative List in 2010, was intended to identify the change of vegetation structures by reviewing past references, pictures, research data and additionally conducting a site survey. Also, it was designed to draw up measures for restoring vegetation suitable for historically and culturally valuable Namhan Mountain Fortress. According to the biotope mapping of study site, Quercus spp. forest distributed a greatest part of area with 40.8% of $2,611,823m^2$. Pinus densiflora forest, highly likely to go through ecological succession, was dispersed in the whole region of Cheongryangsan, the area from West Gate to North Gate and the ranges between South Gate to Cheongryangsan with taking 16.5%. Pinus densiflora forest with a low probability of succession amounted to 4.7% and was dispersed mainly in the forest behind Namhansan elementary school. Pinus densiflora going on the ecological succession is distributed a portion of 2.9%. And the currently dying out Pinus densiflora forest amounted to 2.1%. As a result of analysis of the vegetation structure for 19 years, the succession from Pinus densiflora forest to Pinus densiflora and succession from Quercus spp. mixed forest to Quercus spp. forest to Carpinus laxiflora forest were predicted. Additionally, Quercus spp. expanded its dominance over time. According to the characteristics of each classified zone, the site was categorized into $553,508m^2$ area of Pinus densiflora forest area for the landscape maintenance, $114,293m^2$ area of Pinus densiflora forest area for the landscape restoration, $205,306m^2$ area of Pinus densiflora forest area for the disclimax, and $1,169,973m^2$ area of Pinus densiflora forest area for inducing ecological succession.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.691-709
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• 2011

This study was performed to classify habitat types depending on environmental factors and to find out distribution characteristics of functional feeding groups of aquatic insects which were collected at that habitat types. Field survey was conducted twice in a year for every spring and fall from 2007 to 2008 for 38 sites in the Geum River. During the field survey 15 environmental factors were measured at each 38 sites and analyzed by similarity analysis method to classify habitat types. The result of similarity analysis showed that the 38 sites could be grouped into 7 classes like as C1 and C3 class belong to Head water(HD), C2 and C4 and C5 class belong to Middle stream(MS), C6 and C7 class belong to Large River(LR) based on euclidean distances 4. And also, we could extract the main environmental factors affecting the classification of habitat types such as Stream Width and Elevation of physical environmental factors, Water Temperature, Conductivity and DO of chemical environmental factors, percentages of Sand, Silt and Gravel of substrate factors. Total 142 species of aquatic insects in 46 families, 9 orders were collected during the field surveys and the occurrence number of species and individuals showed high correlation with the Velocity factor and the percentage of Sand factor of each habitat types. In addition, correlation analysis between functional feeding groups and environmental factors represented that (1) Filtering-collectors(FC) affected by Velocity, Stream Width and Silt, (2) Gathering-collector(GC) affected by Velocity, (3) Predator(P) affected by Elevation, Velocity, Boulder, Conductivity and Sand, (4) Plant-piecer(PP) affected by Water Width and Silt, (5) Scraper(SC) affected by Elevation and Conductivity, (6) Shredder(SH) affected by Elevation, Boulder, DO, pH, Conductivity and Water Temperature respectively. As a result of this study, Elevation, Stream Width, Velocity, Conductivity, Water Temperature and percentage of Sand factors which were deduced by stepwise multiple regression analysis had correlations($r{\geqq}0.600$, p<0.01) with biota community inhabitation. Therefore these six environmental factors were regarded as major environmental factors that might affect highly the distribution of functional feeding groups in stream ecosystem of the Geum River.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.2
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• pp.33-40
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• 2014

The purpose of this study is to examine vegetation of the outer walls of the Jeongyi Town Wall in Jeju and analyze the characteristics and problems identified, for suggesting preliminary data for selecting species of plants appropriate for the greening of the walls in the southern temperate climate region, including Jeju. The result of this study is as follows. The number of plants growing naturally around the walls of the town was identified to be 52 taxa. Based on the list of naturalized plants, there are 5 taxa; Sonchus oleraceus, Houttuynia cordata, Crassocephalum crepidioides, Erigeron annuus and Lamium purpureum. The number of species by district was from 3 to 14 taxa with 7.1 taxa on average. Analyzing by the constancy class, plants in class III included Sedum bulbiferum, Trichosanthes kirilowii, Hedera rhombea and Boehmeria nivea. Manipulation of the species composition table shows that the number of plant species growing naturally around the walls of Jeongyi Town Wall is a total of 52 taxa, including 11 taxa by differential species of community and 41 taxa by companion species. The types of plants very useful for the covering of the walls are evergreen climbing vine, such as Hedera rhombea, Ficus thunbergii and Euonymus fortunei and deciduous climbing vine, such as Parthenocissus tricuspidata, Trichosanthes kirilowii and Paederia scandens. In addition, Ficus stipulata is identified as a vegetation more appropriate for the southern-ward lattice-blocked walls. Woody plants, such as Akebia quinata, Celastrus flagellaris, Ampelopsis brevipedunculata for. citrulloides, Rubus hirsutus, Clematis apiifolia and herbaceous plants, such as Dioscorea tenuipes, D. quinqueloba, D. nipponica, Cayatia japonica and Paederia scandens var. angustifolia are highly useful materials for climbing plants for covering the walls of the southern province. Pteridophyte, such as Lemmaphyllum microphyllum, Pteris multifida, Cyrtomium falcatum and Lygodium japonicumare suggested as very useful for increasing unique regional characteristics of the southern province, including Jeju.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.1
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• pp.53-59
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• 2010

The spatial variability in the food chain structure of an estuarine environment(Nanakita estuarine, Japan) was investigated using stable carbon and nitrogen isotope. Potential organic matter sources(TP:Terrstrial Plant, MPOM:Marine particulate organic matter, BMA:Benthic microalgae, EPOM:Estuarine particulate organic matter), sedimentary organic matter and benthic invertebrates(Nuttallia olivacea and Nereidae) were sampled at four locations with different tidal flat types(e.g. sanddy, sanddy-muddy and muddy). The main objective of the present study was to determine food sources of Nuttallia olivacea and Nereidae along with small-scale spatial variability within the community of benthic invertebrates. TP(${\delta}^{13}C=-26.6{\pm}0.76$ and ${\delta}^{15}N=2.7{\pm}0.31$) and EPOM(${\delta}^{13}C=-25.5{\pm}0.13$ and ${\delta}^{15}N=5.2{\pm}0.46$) were isotopically distinct from BMA(${\delta}^{13}C=-16.3$ and ${\delta}^{15}N=6.2$) and MPOM(${\delta}^{13}C=-19.6{\pm}0.08$ and ${\delta}^{15}N=8.9{\pm}1.70$). ${\delta}^{13}C$ values of sedimentary organic matter showed a distinct gradient in the range of -27.4 to -22.8‰ with a declining trend from the upstream to the downstream stations. The stable carbon and nitrogen isotope values of benthic invertebrates in the study site was -22.8 to -18.4‰ for ${\delta}^{16}C$ and 8.1 to 11.9‰ or ${\delta}^{15}N$, respectively. Mixing model(Isosource) calculations based on stable isotope measurements showed that benthic invertebrates of Nuttallia olivacea and Nereidae were found to be dominated by MPOM and BMA in stations. Whereas, TP and EPOM showed little influence to benthic invertebrates. The current result suggests that the different contribution for benthic invertebrates should be affected by both seasonal variation and physical factor among stations.