• Applied Biological Chemistry
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• v.40 no.6
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• pp.551-555
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• 1997

This experiment was carried out to elucidate the biological activity and absorption characteristics of flavonoids in Rhizobium and Bradyrhizobium and to obtain basic information on host specific nodulation by flavonoids in rhizobium-legume symbiosis. The purpose of the present study was to explore the biological activity and the flavonoid absorption indicates that host-specificity is induced by flavonoids in symbiotic nitrogen fixation. Biological activity increased by daidzein and genistein treatment on B. japonicum KCTC 1539 whereas decreased by luteolin treatment but increased by luteolin treatment on R. meliloti whereas decreased by daidzein and genistein treatment. Daidzein and genistein are absorbed by B. japonicum, KCTC 1539 at higher rate than other flavonoids. Especially, luteolin was absorbed at a least rate. Luteolin are absorbed by R. meliloti KCTC 2353 at higher rate than other flavonoids. Especially, daidzein and genistein was absorbed at a least rate.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.134-138
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• 1997

The objective of this study was to examine the effect of phosphorus deficiency on nitrogen fixation and photosynthesis of nitrogen fixing soybean plant under $CO_2$ enrichment condition. The soybean plants(Glycine max [L.] Merr.) inoculated with Bradyrhizobium japonicum MN 110 were grown with P-stressed(0.05 mM-P) and control(1 mM-P) treatment under control$(400\;{\mu}l/L\;CO_2)$ and enrichment$(800\;{\mu}l/L\;CO_2)$ enviromental condition in the phytotron equipped with high density lamp$(1000\;{\mu}Em^{-2}S^{-1})$ and $28/22^{\circ}C$ temperature cycle for 35 days after transplanting(DAT). At 35 DAT, phosphorus deficiency decreased total dry mass by 64% in $CO_2$ enrichment condition, and 51% in control $CO_2$ condition. Total leaf area was reduced significantly by phosphorus deficiency in control and enriched $CO_2$ condition but specific leaf weight was increased by P deficiency. Phosphorus deficiency significantly reduced photosynthetic rate(carbon exchange rate) and internal $CO_2$ concentration in leaf in both $CO_2$ treatments, but the degree of stress was more severe under $CO_2$ enrichment condition than under control $CO_2$ environmental condition. In phosphorus sufficient plants, $CO_2$ enrichment increased nodule fresh weight and total nitrogenase activity(acetylene reduction) of nodule by 30% and 41% respectively, but specific nitrogenase activity of nodule and nodule fresh weight was not affected by $CO_2$ enrichment in phosphorus deficient plant at 35 DAT. Total nitrogen concentrations in stem, root and nodule tissue were significantly higher in phosphorus sufficient plant grown under $CO_2$ enrichment, but nitrogen concentration in leaf was reduced by 30% under $CO_2$ enrichment. These results indicate that increasing $CO_2$ concentration does not affect plant growth under phosphorus deficient condition and phosphorus stress might inhibit carbohydrate utilization in whole plant and that $CO_2$ enrichment could not increase nodule formation and functioning under phosphorus deficient conditions and phosphorus has more important roles in nodule growth and functioning under $CO_2$ enrichment environments than under ambient condition.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.546-550
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• 1997

This study was carried out to elucidate the biological characteristics of Rhizobia in biological nitrogen fixation system. The results of investigation were as follows; Polyacrylamide gel electrophoresis pattern of root lectin in the presence of SDS was ascertained electrophoretically and chromatographically. The purified root lectin formed immunoprecipitin line with anti lectin rabbit IgG. Root lectin, seed lectin and root exudate were tested for chemotactic ability. Chemotactic responses of RCR3407 and KCTC2422 toward root exudate were stronger than those of seed lectin and root lectin, but there didn't occur chemotactic responses of LPN100, not bound with seed lectin and that of LPN101, bound with seed lectin toward root exudate, root lectin and seed lectin. RCR3407, KCTC2422 and LPN-101, which nodulated with soybean, interacted with soybean lectin, but not with pea lectin. LPN-100, which was not nodulated with soybean, didn't interact with soybean lectin.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.4
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• pp.1-15
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• 2017

Eutrophication of surface waters is of concern worldwide, because it can result in many undesirable water-quality and ecological problems, such as hypoxic 'dead' zones and harmful algal blooms, both associated with considerable economic costs. In this study, we used LSM (Land Surface Model) to simulate nitrogen in five major rivers in the Southern Korean Peninsula. The main objective of this research was to enhance nitrogen data for input of LM3V model in South Korea. Input data for nitrogen fluxes were categorized into three sections including agriculture fertilizer, livestock manure, atmosphere deposition, biological fixation, and sewage pollutants were used as the nitrogen input. For using LM3V model, the nitrogen input data were regenerated by considering states of agriculture and industry in South Korea at a $1/8^{\circ}$ resolution. Then, we simulated stream/river flows and N loads throughout the entire drainage networks in South Korea at a $1/8^{\circ}$ resolution. By using the same parameters for the entire country ($100,210km^2$), composed of 5 river basins with varying climate and land use, the model simulates spatial (11 sites) and temporal (1999~2010) patterns of flows and nitrate-N loads are resonable by comparing observed flow and nitrate-N loads. The r (Pearson's linear correlation) for water temperature, flow and nitrate-N at river were 080~0.93, 0.62~0.92 and 0.5~0.9 respectively. Based on enhanced N input data and model results, we find that LM3V model as land surface model can be applied in South Korea with interaction of atmosphere and land conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.60-65
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• 2016

The main objective of this research was to estimate the total mass of nitrogen discharged from various sources in paddy field area of South Korea in 2010 and 2013. Input and output budgets for nitrogen were estimated by mass balance approach. The mass balance approach reduces the effect of flow variations, and the large scale approach minimizes local effects, resulting in easier and faster establishment of strategy for nonpoint pollution problems. Nitrogen inputs were chemical fertilizer, compost, atmospheric deposition, biological fixation, and agricultural water, while crop uptake, denitrification, volatilization, and infiltration were nitrogen outputs. The estimated total nitrogen inputs for paddy field in South Korea were $266,211ton\;yr^{-1}$, $260,729ton\;yr^{-1}$, while those of total nitrogen outputs were $168,463ton\;yr^{-1}$, $164,994ton\;yr^{-1}$ in 2010 and 2013, respectively. Annual amounts of potential nitrogen outflow from paddy field were $97,748ton\;yr^{-1}$, $95,735ton\;yr^{-1}$ in 2010 and 2013. Also, annual rate of potential nitrogen outflow were 36.7%, 36.7% in 2010 and 2013, respectively.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.232-237
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• 1997

Soybean plants inoculated Bradrhizobium japonicum MN 110 were grown in outdoor perlite pots with nitrogen free nutrient solution containing 1.0 mM-P(control) and 0.05 mM-P(stress) and harvested at 28, 35, 42 and 49 days after transplanting (DAT) to examine the effect of phosphorus deficiency on ureide concentration of and distribution to diffrent plant organ in nitrogen fixing soybean plant during the vegetative growth. Total dry mass of control plants increased 8.9 fold and that of phosphorus deficient plant increased 2.7 fold during the experimental period. Phosphorus deficiency reduced total phosphorus and nitrogen accumulation by 80%,40% respectively, at 28 DAT and 93%, 84%, respectively, at 49 DAT. Nitrogen concentration was reduced by phosphorus deficiency in all tissues with leaf and stem tissues affected to a greater degree than nodule and root tissues at every sampling date. Phosphorus deficiency significantly reduced soluble reduced-N and ureide-N concentration in leaf and stem but did not affect those in root. The proportion of soluble reduced-N in leaf was reduced from 60% to 50% but increased from 10% to 20% in the roots. The proportion of ureide-N in leaf of control plants was higher than that in phosphorus deficient plants, whereas, roots of phosphorus deficient plants contained a higher propotion of ureide-N than those of control plants. These indicated that phosphorus deficiency not only inhibit nitrogen fixation of nodules but also restrict the translocation of fixed nitrogen out of the root system into the xylem.(Received April 4, 1997; accepted May 2, 1997)

• Journal of Environmental Policy
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• v.3 no.1
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• pp.95-117
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• 2004

This study was conducted to estimate nitrogen discharge from Korea (southern part of Korean peninsula) as NPS(non-point source) by mass balance approach; input and output analyses of nitrogen using existing data available. The material flow was sectored into three different activities; agricultural (raising crop and animals), human and natural activities in forest and urban areas. Atmospheric deposition, biological nitrogen fixation, inorganic fertilizers and manures applied, animal feed and imported foodstuffs such as crops, meat and fish were the inputs in this study, while ammonia volatilization, denitrification, human and animal waste generation, crop and meat production, and discharge into river to ocean were the outputs. The estimated total nitrogen input was $1,194.5{\times}10^3$ tons N/year and the river discharge was 408 to $422{\times}10^3$ tons N/year, of which 66 to 71% was from NPS. In detail, the estimated NPS discharges were respectively $8,274\;kg\;N/km^2$/year from agricultural area, $730\;kg\;N/km^2$/year from forest and $7,657\;kg\;N/km^2$/year from the other land areas such as urban and industrial area.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.262-271
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• 2008

Natural abundances of stable isotopes of nitrogen and carbon (${\delta}^{15}N$ and ${\delta}^{13}C$) are being widely used to study N and C cycle processes in plant and soil systems. Variations in ${\delta}^{15}N$ of the soil and the plant reflect the potentially variable isotope signature of the external N sources and the isotope fractionation during the N cycle process. $N_2$ fixation and N fertilizer supply the nitrogen, whose ${\delta}^{15}N$ is close to 0%o, whereas the compost as. an organic input generally provides the nitrogen enriched in $^{15}N$ compared to the atmospheric $N_2$. The isotope fractionation during the N cycle process decreases the ${\delta}^{15}N$ of the substrate and increases the ${\delta}^{15}N$ of the product. N transformations such as N mineralization, nitrification, denitrification, assimilation, and the $NH_3$ volatilization have a specific isotope fractionation factor (${\alpha}$) for each N process. Variation in the ${\delta}^{13}C$ of plants reflects the photosynthetic type of plant, which affects the isotope fractionation during photosynthesis. The ${\delta}^{13}C$ of C3 plant is significantly lower than, whereas the ${\delta}^{13}C$ of C4 plant is similar to that of the atmospheric $CO_2$. Variation in the isotope fractionation of carbon and nitrogen can be observed under different environmental conditions. The effect of environmental factors on the stomatal conductance and the carboxylation rate affects the carbon isotope fractionation during photosynthesis. Changes in the environmental factors such as temperature and salt concentration affect the nitrogen isotope fractionation during the N cycle processes; however, the mechanism of variation in the nitrogen isotope fractionation has not been studied as much as that in the carbon isotope fractionation. Isotope fractionation factors of carbon and nitrogen could be the integrated factors for interpreting the effects of the environmental factors on plants and soils.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.300-306
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• 2022

The mitogen-activated protein kinase (MAPK) signaling cascade is essential for a wide range of cellular responses in plants, including defense responses, responses to abiotic stress, hormone signaling, and developmental processes. Recent investigations have shown that the stress, ethylene, and MAPK signaling pathways negatively affect the formation of nitrogen-fixing nodules by directly modulating the symbiotic signaling components. However, the molecular mechanisms underlying the defense responses mediated by MAPK signaling in the organogenesis of nitrogen-fixing nodules remain unclear. In the present study, I demonstrate that the Medicago truncatula mitogen-activated protein kinase kinase 5 (MtMKK5)-Medicago truncatula mitogen-activated protein kinase 3/6 (MtMPK3/6) signaling module, expressed specifically in the symbiotic nodules, promotes defense signaling, but not ethylene signaling pathways, thereby inhibiting nodule development in M. truncatula. U0126 treatment resulted in increased cell division in the nodule meristem zone due to the inhibition of MAPK signaling. The phosphorylated TEY motif in the activation domain of MtMPK3/6 was the target domain associated with specific interactions with MtMKK5. I have confirmed the physical interactions between M. truncatula nodule inception (MtNIN) and MtMPK3/6. In the presence of high expression levels of the defense-related genes FRK1 and WRKY29, MtMKK5a overexpression significantly enhanced the defense responses of Arabidopsis against Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Overall, my data show that the negative regulation of symbiotic nitrogen-fixing nodule organogenesis by defense signaling pathways is mediated by the MtMKK5-MtMPK3/6 module.

• Journal of Applied Biological Chemistry
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• v.56 no.4
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• pp.235-239
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• 2013

This study was carried out to investigate the plant growth promoting activity of hairy vetch (Vicia villosa Roth) on reclaimed land. At the previous research, Rhizobium sp. RH84 was isolated and selected for further study from hairy vetch. For the investigation of plant growth promoting effects by the Rhizobium sp. RH84, production of indole acetic acid (IAA), siderophore, phosphate solubilization and nitrogen fixation were tested and other characters were examined. As results, RH84 produced $9.03{\mu}g$ IAA per mL and showed nitrogen fixation activity. With the treatment of Rhizobium sp. RH84 to hairy vetch showed good growth at 0.3% salty reclaimed soil, and the production yield was increased up to 56% at field test. From these results, it was confirmed that the Rhizobium sp. RH84 would be used as a green manure for hairy vetch under the salty condition of reclaimed land.