• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.147-154
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• 1999

This study was carried out to obtain reasonable management method of salt-affected soil for ecological restoration in the reclaimed land. Chemical properties of reclaimed soil was investigated base on reclamation years. Ionic acitivity in soil and satruration extract were analyzed to estimate the effect of salt interception by planting ground treatment. The soil porperties of reclaimed land was saline-sodic soil with $11.3dSm^{-1}$ of electrical conductivity, 34.8% of exchangeable sodium percent in first reclamation year. Electrical conductivity, exchangeable sodium and exchangeable chlorine were remarkedly decreased during six years after reclamation but chemical properties of reclaimed soil was unsuitable status for tree growth. Exchangeable sodium perecnt was higher in the neighborhood parks and street tree sites than in the buffer green spaces and was higher in subsoil than in topsoil of profile in all sites. Content of soduim, chloride and sulfate in saturation extract were more than other ions. Content of soduim and chloride were higher in the neighborhood parks and street tree sites than in the buffer green spaces and were higher in subsoil than in topsoil. Content of calcium plus magnesium of soil was higher in the buffer green space than in the neighborhood park and street tree but content of calcium and magnesium in saturation extract were higher, as result from exchangeable sodium, in the neighborhood parks and street tree sites than in the buffer green spaces. Concentration of salt in soil showed the difference with mounding height and planting ground treatment. The lowest concentration of salt appeared in buffer green spaces and street tree sites was the highest. Salt interception by mounding height in the same planting ground treatment was more effective 120cm of mounding height than 70cm of mounding height.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.4
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• pp.306-311
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• 1995

A nutrient solution culture experiment was conducted in the greenhouse of Suwon Campus, Kyung-Hee University from May 22 to July 10, 1995, to determine the effects of sulful application on seedling growth of Kwanganok and Hwengsungok cultivars of corn. Plants were harvested at weekly interval for seven weeks, at which time plant height, leaf area and dry matter yield of corn seedling were measured. Sulfer was treated with $MgSO_4{\cdot}7H_2O$ so that sulfur concentrations of cultural solution are 0, 68, 136 and 204ppm for treatments of without sulfer(-S), control(C), twofold concentration(2S) of control and threefold contration(3S) of control, respectively. The plant height, leaf area and dry matter yield during the seven weeks of Kwanganok cultivar was decreased in order of C>2S>3S>-S, 2S>C>3S>-S and 2S>3S>C>-S application pot, respectively. In Hwengsungok cultivar, those were decreased in order of C>-S>3S>2S, C>3S>2S>-S and C>3S>-S>2S application pot, respectively. The total plant height, leaf area and dry matter yield during the whole period of Kwanganok and Hwengsungok cultivars were decreased in the seedling grown under without sulfur treatment compared with the other sulfur treatments. In Hwengsungok cultivar, plant height, leaf area and dry matter yield of seedlings were increased more in control sulfur treatment pot than the other sulfur treatment pot during the whole period. The crop growth rates of seedling of both cultivars in all treatments were slowly increased until the 3th week after planting and its were showed up and down CGR's thereafter, but Hwengsungok cultivar with C treatment pot maintained a steady increase in CGR until the end of the experiment period.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.314-324
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• 1997

This study was conducted to investigate whether 1) photosynthetic pigments(chlorophylls and carotenoids) are formed in dodder plant(Cuscuta australis), 2) there are any characteristics in the pigment biosynthesis, compared to that of other normal plants, and 3) dodder responds to some herbicides having target site on chloroplast. 1. Chlorophyll content of dodder tendrill grown under a natural daylight was 9 times and 50 times lower than that of field bindweed stem and leaf, respectively. 2. The photosynthetic pigment contents varied in different tissues, being higher in a apical region than in a lower region of seedling or tendrill. Chlorophyll wasn't almost observed below the 4th internode from the upper. 3. Pigment contents were greatly dependent on light intensity so that there were 4 to 6 times difference among light conditions. When the shoot containning low pigment contents under natural light, was incubated in growth chamber with various light intensities, the pigment contents were increased by 3 times of initial contents at about 97${\mu}E$ $m^{-2}s^{-1}$PAR. While the change in pigment contents was not observed at above 450${\mu}E$ $m^{-2}s^{-1}$PAR 4. Exogenous supply of 5mM 5-aminolevulinic acid increased protochlorophyllide by 7 times and 1.4 times in the etiolated shoot from field bindweed rhizome and in dodder stem, respectively, showing that dodder relatively has a low response to 5-aminolevulinic acid. 5. Pigment loss was observed in the treatment of paraquat, norflurazon, oxyfluorfen and diuron, and protoporphyrin IX was accumulated by oxyfluorfen as in normal plants Based on above results, several chracteristics of pigment biosynthesis in dodder seem to be summerized as follows. Photosynthetic pigment biosynthesis in Cuscuta australis runs even in low level. The pigment contents is differentially distributed in different regions and their contents seem significantly to be controlled by light intensities. Especially, chloroplast rapidly tends to degenerate with the development of tissue. Some herbicides having target site on chloroplast induce damage to dodder stem but are unlikely to control it well in field, except paraquat, due to low chloroplast activity and parasitic mode of nutrition.

• Korean Journal of Medicinal Crop Science
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• v.1 no.1
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• pp.28-37
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• 1993

The low seed propagation is one of the problem needed a lot of seed tuber for the propagation in yam. Therefore this experiment was carried out to understand the possiblility of seed tuber propagation by tissue culture of yam. In-vitro stem node of yam was cultured by concentration treatments of 1/2, 1/4 and 1/8 with MS medium additted with each concentration levels of IAA, NAA, IBA, kinetin and BA. Acorrding to the Iower concentration than MS medium, length of shoots was promoted, leaf emergence shoots and rooting shoots were increased at 1/8 MS medium during the culturing period of stem node in yam. Fixed IBA and kinetin under the concentration of MS mdeium was inhibited severely by the heigh concentration additted with lAA $1mg\;/\;{\ell}\;and\;NAA\;4mg\;/\;{\ell}$. But fixed IBA $5mg\;/\;{\el}l\;and\;kinetin\;2mg\;/\;{\ell}$ with concentration of 1/8MS medium was remarkably promoted leaf emergence shoots and rooting shoots by $1mg\;/\;{\ell}$ of additted lAA and NAA. Percentage of induced shoots was increased by combination treatments of lAA. $1.5mg\;/\;{\ell}\;and\;kinetin\;2mg\;/\;{\ell}$, also leaf emergence shoots and rooting shoots were promoted by combination treatments of lAA $1.5mg\;/\;{\ell}\;and\;kinetin\;2mg\;/\;{\ell}$.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.37-44
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• 2005

Microspores were isolated from pepper (Capsicum annuum L.) anthers by using a micro-blender and cultured in modified NLN medium at $25^{\circ}C$. The influence of pretreatment period at $32^{\circ}C$, adding the 2-hydroxynicotinic acid to a pretreatment medium, and co-pretreatment anthers with microscopes on the induction of embryo were examined. Globular and torpedo embryos were observed from 3 weeks after culture. Embryo development was not synchronized within culture. After 4 weeks in culture, in addition to globular and torpedo embryos, cotyledonary embryos were observed. Normal cotylodonary embryos developed into plantlets when transferred to a solid hormone free B5 medium containing $2\%$ sucrose. Embryo yields were significantly higher after 1- and 2-day pretreatment at $32^{\circ}C$. However the development of embryo ceased at the globular or heart stage. In contrast, embryo yields were lower after 3- to 6-day pretreatment at $32^{\circ}C$ and embryo developed at the cotyledonary stage. After adding the 2-hydroxynicotinic acid to anther pretreatment solution, embryo yields were slightly increased. However most embryos occurred were at the globular or heart stage. Co-pretreatment of microspores with anthers was deleterious for embryo induction and development. AS far as we know, this is the first report of success in obtaining high frequency of embryogenesis and plantlets formation from isolated microspores of pepper. Although the culture conditions have to be optimized further, this promising microspore culture system can be used for genetic transformation, selection for dominant and recessive traits as well as for the production of homozygous doubled haploid plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.264-273
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• 1992

Availability of white clover (Trifolium repens L.) has been limited due to its poor introduction to swards and lack of persistence under improper grazing management. This experiment was conducted to determine the effects of initial defoliation stage and defoliation interval on the growth of white clover varieties. Individual plants of Regal (large leaf), Louisiana S.1 (medium-large leaf), Grasslands Huia (medium-small leaf) and S184 (small leaf) were grown in containers (4.5 $\times$ 13.5 cm) containing a 1:2:1 soil:sand:Promix until reaching to the stage of 1, 4, or 8 trifoliolates, and then clipped to remove all fully expanded leaves every 7 or 28 days (d). For analysis of morphological parameters, plants were sampled on the final harvest date (0 d), and 7, 14, 21, and 28 d after the final harvest date. Harvested dry weight (dw) of all varieties declined as defoliation interval declined or initial defoliation was made earlier. That of Regal was the highest as initial defoliation was delayed. On the 7 d regrowth shoot and root dw were increased as initial defoliation was delayed or interval lengthened, whereas on the 28 d regrowth the trend was alleviated. Root dw and biomass of Regal were higher than the other varieties during the whole regrowing period, when the increase of biomass resulted from that of shoot dw. Leaf areas and petiole lengths of all varieties declined under 7 d defoliation interval. The area and the length declined with earlier initial defoliation on the 7 d regrowth but not on the 28 d regrowth. Stolon length and growing tips of S184 were the highest and increased more steeply during regrowth, while those of Regal were the lowest and did slightly. It is concluded that the continuous defoliation and the first defoliation at earlier growth stage have detrimental effects on growth of white clover, although larger leaf types are more productive but less persistent in a sward than smaller leaf types.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.331-338
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• 2007

The major fungal diseases which effecting garlic storage are blue mold and dry rot, caused by Penicillium hirsutum and Fusarium oxysporum, respectively. In order to reduce the damage by the pathogenic fungi, here we report the effects of 11 fungicides tested to reduce spoilage during storage of garlics. In the in vitro antimicrobial activity test, the fungicides, diphenylamine, prochloraz and tebuconazole showed 0.3, 2.2, and 1.3 nun inhibition zone to F. oxysporium, and cyprodinil, diphenylamine, fenbuconazole, hexaconazole, penconazole, prochloraz, propiconazole, pyrimethanil and tebuconazole exhibited 0.2, 2.4, 0.8, 0.4, 1.2, 1.5, 1.2, 0.4 and 1.5 mm to P. hirsutum, respectively. To test the in vivo control effect, when the diphenylamine, prochloraz, and tebuconazole were treated by standard concentration, the fungal mycelium of F. oxysporium started to grow 5 days after inoculation, and 80, 63.3 and 83.3% of the inoculated cloves are infected 11 days after inoculation. When the tebuconazole were treated by standard concentration, the P. hirsutum was completely inhibited the growth of the fungi. In case of diphenylamine, penconazole and propiconazole treatment, the P. hirsutum was observed 7 days after inoculation and $20{\sim}23.3%$ of the cloves were infected 11 days after inoculation. When cyprodinil, prochloraz and pyrimethanil were treated, pathogens occurred 5 days after inoculation and $60{\sim}100%$ of the cloves infected 11 days after inoculation. Three fungicides such as diphenylamine, prochloraz and tebuconazole also suppressed remarkably the infection and growth of F. oxysporium and P. hirsutum on garlic when both of the pathogens are inoculated after the garlic cloves were dipped for 10 min in the suspension of each agrochemical. Overall, diphenylamine, prochloraz and tebuconazole showed effective control efficacy on dry rot and blue mold There was significant correlation between in vitro and in vivo assay in diphenylamine and prochloraz to F. oxysporum and cyprodinil, prochloraz and pyrimethanil to P. hirsutum.

• Journal of Food Hygiene and Safety
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• v.32 no.1
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• pp.8-13
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• 2017

This study was conducted to develop an agent-based computing platform enabling simulation of on-farm produce contamination by enteric foodborne pathogens, which is herein called PPMCS (Preharvest Produce Microbial Contamination Simulator). Also, fecal contamination of preharvest produce was simulated using PPMCS. Although Agent-based Modeling and Simulation, the tool applied in this study, is rather popular in where socio-economical human behaviors or ecological fate of animals in their niche are to be predicted, the incidence of on-farm produce contamination which are thought to be sporadic has never been simulated using this tool. The agents in PPMCS including crop, animal as a source of fecal contamination, and fly as a vector spreading the fecal contamination are given their intrinsic behaviors that are set to be executed at certain probability. Once all these agents are on-set following the intrinsic behavioral rules, consequences as the sum of all the behaviors in the system can be monitored real-time. When fecal contamination of preharvest produce was simulated in PPMCS as numbers of animals, flies, and initially contaminated plants change, the number of animals intruding cropping area affected most on the number of contaminated plants at harvest. For further application, the behaviors and variables of the agents are adjustable depending on user's own scenario of interest. This feature allows PPMCS to be utilized in where different simulating conditions are tested.

• Research in Plant Disease
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• v.9 no.4
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• pp.229-236
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• 2003

The 1080 epiphytic bacteria obtained from 370 samples of pome and stone fruits including apple, pear, peach, grape, apricot and Chinese quince were screened for antagonistic activity against postharvest pathogens, Penicillium expansum, Alternaria alternata and Botrytis cinerea. Among tested antagonistic bacteria, eight bacterial isolates inhibited mycelial growth of the postharvest pathogens and were identified as Bacillus amyloliquefaciens (three strains), B. megaterium, B. subtilis var. gladioli, B. licheniformis, B. pumilus and Serratia marcescens based on biochemical characteristics and utility of carbon and nitrogen compounds (Biolog system). Eight carbohydrates were evaluated for their effect on mycelial growth and germination of the postharvest pathogen, P. expansum to select nutrients for enhancing bio-control efficacy. The growth of four selected antagonists, B. amyloliquefaciens P43-2, B. amyloliquefaciens A71-2, B. licheniformis P94-1, and S. marcescens P76-9 were also tested. As a result, 1% glucose (w/v) strongly stimulated growth of the antagonists, suppressed mycelial growth of the postharvest pathogen, and had a little comparatively stimulatory effect on germination of the the postharvest pathogen. It was confirmed that the addition of 1% glucose (w/v) greatly enhanced biocontrol effect of B. amyloliquefaciens P43-2, B. licheniformis P94-1, and S. marcescens P76-9. Application of B. amyloliquefaciens P43-2, B. licheniformis P94-1, and S. marcescens P76-9 with the addition of 1% glucose (w/v) increased the control efficacy up to 48%, 46%, 14% compared with those of the antagonists without glucose, respectively. When the antagonists were applied to control postharvest disease caused by P. expansum in apple wounds, the population of B. amyloliquefaciens P43-2 and B. licheniformis P94-1 increased until 4 days after inoculation (DAI) of the antagonists and then decreased from 10 DAI. Meanwhile the population of S. marcescens P76-9 decreased at early stage (4 DAI), but increased from 7 DAI, and finally maintained constantly until 10 DAI in apple wounds.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.436-447
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• 2004

Wetland plants have evolved specialized adaptations to survive in the low-oxygen conditions associated with prolonged flooding. The development of internal gas space by means of aerenchyma is crucial for wetland plants to transport $O_2$ from the atmosphere into the roots and rhizome. The formation of tissue with high porosity depends on the species and environmental condition, which can control the depth of root penetration and the duration of root tolerance in the flooded sediments. The oxygen in the internal gas space of plants can be delivered from the atmosphere to the root and rhizome by both passive molecular diffusion and convective throughflow. The release of $O_2$ from the roots supplies oxygen demand for root respiration, microbial respiration, and chemical oxidation processes and stimulates aerobic decomposition of organic matter. Another essential mechanism of wetland plants is downward water movement across the root zone induced by water uptake. Natural and constructed wetlands sediments have low hydraulic conductivity due to the relatively fine particle sizes in the litter layer and, therefore, negligible water movement. Under such condition, the water uptake by wetland plants creates a water potential difference in the rhizosphere which acts as a driving force to draw water and dissolved solutes into the sediments. A large number of anatomical, morphological and physiological studies have been conducted to investigate the specialized adaptations of wetland plants that enable them to tolerate water saturated environment and to support their biochemical activities. Despite this, there is little knowledge regarding how the combined effects of wetland plants influence the biogeochemistry of wetland sediments. A further investigation of how the Presence of plants and their growth cycle affects the biogeochemistry of sediments will be of particular importance to understand the role of wetland in the ecological environment.