• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.362-367
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• 2008

The legume-rhizobia symbiosis is an important source of plant growth and nitrogen fixation for many agricultural systems. This study was conducted to investigate the effects of salinity stress on nitrogen fixation and growth of pea (Pisum sativum L.), which has antimutagenic activities against chemical mutagen, inoculated with R. leguminosarum bv. viciae cultured with additional plant-to-rhizobia signal compounds, naringenin (NA,15 uM), methyl-jasmonate (MJ, 50 uM) or both, under greenhouse conditions. Three salinity levels (0.6, 3.0 and $6.0\;dS\;m^{-1}$) were imposed at 3 days after transplanting and maintained through daily irrigations. Addition of signal compounds under non-stress and stress conditions increased dry weight, nodule numbers, leaf area and leaf greenness. The inducers increased photosynthetic rate under non-stress and stress conditions, by approximately 5-20% when compared to that of the non-induced control treatment. Under stress conditions, proline content was less in plants treated with plant-to-bacteria signals than the control, but phenol content was significantly increased, compared to that of the control. The study suggested that pre-incubation of bacterial cells with plant-to-bacteria signals could enhance pea growth, photosynthesis, nitrogen fixation and biomass under salinity stress conditions.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.335-340
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• 1998

This study was conducted to determine the morphological responses of barley seedlings to NaCl stress and to investigate histological changes of cells with transmission electron microscope(TEM) after NaCl stress. Plant height and root length of 10-day old barley seedlings with NaCl stress were reduced and inhibition level was found to be more severe in the plant height than in the root length. The leaf length, leaf width and leaf area were shorter as well with NaCl stress than without NaCl stress. However, there was no difference in the number of roots between NaCl treatments. The weight of dry matter decreased at higher NaCl concentrations, especially at 100mM NaCl. The water content of shoots tend to decrease at higher NaCl concentrations, but there was no difference in the water content of roots, The reduced sugar content was greatly increase than starch. Cellulose content was higher in NaCl stressed-plant than control, and tended to decreased at higher NaCl concentrations. Lignin content also decreased NaCl stressed-plant but there was no tendency at NaCl stress concentrations. Electric conductivity of cell sap with seedlings was high with NaCl stressed-plant. Amount of cell sap gradually increased with time in the roots than in the shoots, The grana of chloroplasts was changed by 150mM NaCl concentration. The christe of mitochondria in root meristematic sells ruined in structure and cell wall of leaf and root was also ruined by NaCl stress.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.236-236
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• 2017

Low soil pH causes from $H^+$ rhizotoxicity results in nutrients unavailability in the growing media, inhibits plant growth, development and reduces crop yields. The present study was carried out to reveal morpholophysiological and biochemical responses of wheat (Triticum aestivum L.) to acidity stress. Four wheat varieties viz. BARI Wheat-21, BARI Wheat-25, BARI Wheat-26 and BARI Wheat-30 were used in the study. Eight-day-old seedlings were exposed to different pH levels (3.5, 4.5, 5.5 and 6.5) of growing media. Acidity stress at any level reduced biomass, water, and chlorophyll contents in all the varieties; whereas BARI Wheat-26 showed the least damage. $H^+$ rhizotoxicity also caused oxidative stress through excess production of reactive oxygen species and methylglyoxal which increase lipid peroxidation in all the varieties but the lowest oxidative damage was observed in BARI Wheat-26 due to better performance of the antioxidant defense and glyoxalase systems. Considering the growth, physiological and biochemical attributes BARI Wheat-26 may be considered as acidity stress tolerant, among the variety examined.

• Plant Resources
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• v.8 no.3
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• pp.202-208
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• 2005

Osmotic stress is one of major limiting factors in crop production. In particular, seasonal drought often causes the secondary disease in the field, resulting in severe reduction in both quality and productivity. Recent efforts have revealed that many genes encoding protein kinases play important roles in osmotic stress signal transduction pathways. Previously, the AtSIK (Arabidopsis thaliana Stress Inducible Kinase) mutants have shown to enhance tolerance to abiotic stresses, accompanying with higher expression of abiotic stress-related genes than did the wild-type plants. In this study, we have transformed potato (cv. Taedong Valley) with the AtSIK expression cassette. Both PCR and RT-PCR using AtSIK-specific primers showed stable integration and expression of the AtSIK gene in individual transgenic lines, respectively. Foliar application of herbicide ($Basta^{(R)}$) at commercial application rate (0.3% (v/v)) revealed another evidence of stable gene introduction of T-DNA which includes the bar gene for herbicide resistance. Overexpression of the AtSIK gene under dual CaMV35S promoter increased sensitivity to salt stress (300 mM NaCl), which was demonstrated by the reduction rate of chlorophyll contents in leaves of transgenic potato lines. These results suggest that possible increase of osmotic tolerance in potato plants may be achieved by antisense expression of AtSIK gene.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.582-593
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• 2022

Among abiotic stresses in plants, drought and chilling stresses reduce the supply of moisture to plant tissues, inhibit photosynthesis, and severely reduce plant growth and yield. Thus, the application of water stress-tolerant agents can be a useful strategy to maintain plant growth under abiotic stresses. This study assessed the effect of exogenous bio-based 2,3-butanediol (BDO) application on drought and chilling response in tomato and turfgrass, and expression levels of several plant signaling pathway-related gene transcripts. Bio-based 2,3-BDOs were formulated to levo-2,3-BDO 0.9% soluble concentrate (levo 0.9% SL) and meso-2,3-BDO 9% SL (meso 9% SL). Under drought and chilling stress conditions, the application of levo 0.9% SL in creeping bentgrass and meso 9% SL in tomato plants significantly reduced the deleterious effects of abiotic stresses. Interestingly, pretreatment with levo-2,3-BDO in creeping bentgrass and meso-2,3-BDO in tomato plants enhanced JA and SA signaling pathway-related gene transcript expression levels in different ways. In addition, all tomato plants treated with acibenzolar-S-methyl (as a positive control) withered completely under chilling stress, whereas 2,3-BDO-treated tomato plants exhibited excellent cold tolerance. According to our findings, bio-based 2,3-BDO isomers as sustainable water stress-tolerant agents, levo- and meso-2,3-BDOs, could enhance tolerance to drought and/or chilling stresses in various plants through somewhat different molecular activities without any side effects.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.1
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• pp.1-11
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• 2016

Currently, urban green space is disappearing due to urbanization, industrialization and various environmental problems including the disruption of the ecology in urban areas. To solve such problems and increase urban green area, roof greening has been suggested as an alternative. Through observing the responses of three plant species (Mukdenia rossii, Dianthus chinensis, and Pachysandra terminalis) plantrd on the soil mixed with Geohumus, this study investigated the effect of Gehumus on soil water content and plant survival. Soil water content of the rooftop soils has been increased when mixed with Geohumus. The responses were proportional to the amount of Geohumus in the mixture. Geohumus exerted a stronger influence on raising soil moisture content for soil A which had lower water-holding capacity. The stress responses of the plants varied in relation to the amount of Geohumus and soil moisture content. The stress response was lowest for Dianthus chinensis and increased in the order of Mukdenia rossii and Pachysandra terminalis. With the highest plant stress, Pachysandra terminalis showed the lowest survival rate among the three species. Without irrigation, the plants survived only for six weeks on green roofs. The survival rate differed depending on the amount of Geohumus mixed. The results of the experiment showed, with some exceptions, that Geohumus helped to improve soil water content, reduce plant stress, and extend plant survival period.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.562-566
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• 2010

SOD2-transgenic $T_3$ petunia line (A2-36-2-1-1-35) was treated with different levels of methyl viologen (MV) to determine its resistance to oxidative stress. Four (4) levels of MV (0, 100, 200, and $400\;{\mu}M$) were applied. The SOD2-transgenic $T_3$ petunia line exhibited a very significant oxidative stress resistance at the highest MV concentration ($400\;{\mu}M$) treatment compared to non-transgenic plant. RNA and protein expression of SOD2 transgene and higher parenchyma cell density in the transgenic petunias exhibiting resistance to oxidative stress proves its contribution to the expression of its resistance to oxidative stress.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04a
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, $50-80\%$ of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, Improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, 50-80% of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.100.2-101
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• 2003

The global regulator, GacS (global antibiotic and cyanide sensor kinase), was required for the increased resistance to hydrogen peroxide occurring as cultures of the rhizobacterium, P. chlororaphis O6, matured. Specific stationary-phase peroxidase and catalase isozymes were absent in the GacS mutant, whereas a manganese-superoxide dismutase isozyme was expressed earlier and to a great extent than wild type. In the wild type cell, transcript accumulation of rpoS was higher in late logarithmic-phase cells than cells from mid logarithmic- or stationary-phase. Transcripts from rpoS in the GacS mutant were reduced in each of these growth phases compared to the wild type expression. The down stream sequence from rpoS lacked sequences encoding a small RNA, rsmZ, found in other pseudomonads and implicated in control of genes activated by the GacS system. These findings suggest that GacS-mediated regulation of RpoS plays role in control of oxidative stress in P. chlororaphis O6 by as yet an unknown mechanism.