• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.405-409
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• 2003

To study the tolerant capacity of anaerobic granular sludge (AGS) to oxygen using semi -dynamic batch experiment, the aerating time, pH of the basal media, reductive inorganic materials, microorganism, and microorganism metabolite were investigated. When the aerating time was higher or lower than 0.5 h, the producing gas activity of sludge was lower than that of the control. The oxygen tolerance of the experimental sludge was the highest at the initial pH 7.2. The producing gas activity of sludge I was higher than that of sludge II. And storage at $4^{\circ}C$ can low the lose of the oxygen tolerance capacity of granular sludge. The producing gas activity of sludge was the highest when KI was added. The growth of aerobic microorganisms and some metabolite could increase the producing gas activity of granular sludge.

• Journal of Plant Biotechnology
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• v.4 no.2
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• pp.53-58
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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.n factors.

• Journal of Forest and Environmental Science
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• v.39 no.4
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• pp.246-253
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• 2023

Salix gracilistyla is widely distributed along riversides in Korea and very good for biomass production by SRC because of its excellent germination ability, but it is necessary to measure drying tolerance for cultivation. The drought tolerance of S. gracilistyla was tested using cuttings, and growth and physiological analysis were performed after irrigation was stopped. The growth inhibition of S. gracilistyla was observed from the day irrigation was stopped, and the soil moisture content decreased to less than 10% on the 25th day after irrigation was stopped. Over 50% of the seedlings turned brown 25 days after watering was stopped. The chlorophyll content of S. gracilistyla decreased dramatically after 25 days of stopping of irrigation. RWC values were unchanged until day 12 after irrigation was stopped but decreased rapidly until day 21, but there was a slightly decreasing trend after that. RWL levels increased slightly during irrigation stops. The proline content of plants subjected to drought stress was 0.91-2.63 mg/0.05 g, 2.75 times higher than that of the control treatment. The sugar content of the drought stress treatment group was 29.77 to 350.66 mg/0.05 g, which increased 12.24 times that of the control treatment. As a result of this study, S. gracilistyla was found to have a drought tolerance almost comparable to that of evergreen broad-leaved trees growing on the land. This study is expected to contribute to the resource utilization S. gracilistyla, a native willow tree of Korea, and the mass production of biomass by SRC.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.53-57
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• 2011

The MuSI is known as a multiple stress resistant gene with several lines. A previous study using RT-PCR showed that the expression of MuSI gene in tobacco plant induced its tolerance to Cd stress. This study was conducted to examine the enhanced Cd tolerance of the MuSI transgenic tobacco plant through germination test and to understand the role of the involved antioxidant enzymes for the exhibited tolerance. Germination rate of MuSI transgenic tobacco was more than 10% higher than that of wild-type tobacco, and seedlings of MuSI transgenic tobacco grew up to 1.6 times larger and greener than seedlings of wild-type tobacco at 200 and 300 ${\mu}M$ Cd. From the third to the fifth day, CAT activities at 100 and 200 ${\mu}M$ Cd and APX activities at 100, 200 and 300 ${\mu}M$ Cd of MuSI transgenic tobacco were up to two times higher than those of wild-type tobacco. MuSI gene is shown to enhance the activities of antioxidant enzymes resulting in higher tolerance to oxidative stress compared with the control plant.

• Research in Plant Disease
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• v.22 no.3
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• pp.213-216
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• 2016

Tomato spotted wilt virus (TSWV) is one of the most destructive viruses in tomato plant. TSWV-GT from the leaves of tomato plant showing top wilt symptom in 2015 was used to screen the tolerance in tomato cultivars. Among 51 cultivars commercially available in Korea, 'TY Smartsama' and 'Marnolia' showed tolerance to the virus in bioassay. Three cvs. 'Titichal', 'TY Sensq', and 'Venekia' were moderate tolerance.

• Journal of Plant Biotechnology
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• v.47 no.4
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• pp.324-329
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• 2020

Reed (Phragmites spp.) is a rhizomatous plant of the Poaceae family and is known as high tolerant plant to heavy metal contaminants. This plant is widely recognized as a Cd root-accumulator, but improved heavy metal tolerance and uptake capacity are still required for phytoremediation efficiency. To enhance capacity of hyperaccumulator plants, ethyl methane sulfonate (EMS) as chemical mutagen has been introduced and applied to remediation approaches. This study aimed to select EMS-mutagenized reeds representing high Cd resistance and large biomass and to investigate their ability of Cd accumulation. After 6 months cultivation of M₂ mutant reeds under Cd stress conditions (up to 1,500 µM), we discovered seven mutant individuals that showed good performances like survivorship, vitality, and high accumulation of Cd, particularly in their roots. Compared to wild type (WT) reeds as control, on average, dry weight of mutant type (MT) reeds was larger by 2 and 1.5 times in roots and shoots, respectively. In addition, these mutant plants accumulated 6 times more Cd, mostly in the roots. In particular, MT8 reeds showed the greatest ability to accumulate Cd. These results suggest that EMS mutagenesis could generate hyperaccumulator plants with enhanced Cd tolerance and biomass, thereby contributing to improvement of phytoremediation efficiency in Cd-contaminated soil or wastewater. Further studies should focus on identifying Cd tolerance mechanisms of such EMS-mutagenized plants, developing techniques for its biomass production, and investigating the practical potential of the EMS mutants for phytoremediation.

• Journal of Environmental Impact Assessment
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• v.15 no.6
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• pp.385-394
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• 2006

Land resources should be managed not only for human utilizations but also for environmental preservation. Based on that, environmental capacity should be estimated in both environmental and developmental ways. This study was performed for developing an estimation model for relative environmental capacity, considering both Development Tolerance Index(DTI), which shows environmental and ecological conservation value and is based on national environmental assessment indicators of the Korea Ministry of Environment, and Development Attractiveness Index(DAI), which shows topographical characteristics and geographical accessibility. The relative environmental capacity in this study can be helpful to coping with the conflict in planning and managing the use of land resources. The relative environmental capacity in this study, however, did not include either environmental or ecological sensitivity of land resources. This limitation should be solved through further research.

• Journal of Environmental Science International
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• v.11 no.11
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• pp.1173-1181
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• 2002

The present study was undertaken to investigate the effect of low temperature and salicylic acid(SA) on the chilling tolerance of acclimated and nonacclimated cucumber(Cucurmis sativus L.) seedlings. The acclimation phenomenon was characterized in chilling-sensitive cucumber seedlings and found to have a significant effect on the survival and shoot dry weights. The injuries experienced by the acclimated seedlings in the third leaf stage were on average smaller by half than those experienced by the nonacclimated seedlings. Chilling also caused a large increase in the free proline levels, regardless of the acclimation status. Exogenous treatment with SA(0.5mM) resulted in improved growth and survival of the nonacclimated chilled seedlings, indicating that SA induced chilling tolerance and SA and acclimation had common effects. The application of cycloheximide in the presence of SA restored the acclimation-induced chilling tolerance. The elevated proline level observed in the cold-treated and SA-treated plants was more pronounced in the light than in the dark at a chilled temperature, indicating that endogenous proline may play a role in chilling tolerance by stabilizing the water status in response to chilling. From these results it is suggested that SA provided protection against low-temperature stress by increasing the proline accumulation, and pre-treatment with SA may induce antioxidant enzymes leading to increased chilling tolerance.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2002.05b
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• pp.468-471
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• 2002

The present study was undertaken to Investigate the effects of low temperature and salicylic acid (SA) on chilling tolerance In acclimated and nonacclimated cucumber seedlings. Acclimation significantly affected survival and shoot dry weights. Injuries of acclimated seedlings at the third leaf stage were on the average smaller by half than those of the nonacclimated ones. Chilling caused a large increase in free proline levels, regardless of acclimation status. Exogenous treatment with SA resulted in improvement in growth and survival of acclimated, chilled seedlings, indicating SA and acclimation have common effects. Cycloheximide treatment In the presence of SA restored acclimation-induced chilling tolerance. An elevated proline level was observed in cold-treated and SA- treated plants and the level was more pronounced in the light than in the dark at chilled temperature, indicating that endogenous proline may play a role in chilling tolerance.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.373-385
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• 1994

Resistance to paraquat (1,1'-dimethyl-4,4'-bipyridilium ion) has developed in 12 species of 8 genera to which paraquat has been applied 6 to 10 times per year for 5 or more years. In recent years, tolerance to paraquat has been found in Rehmannia glutinosa (Gaertn.) Liboch. ex Fisch. & Mey. which has never been applied with any herbicides involving paraquat. In this review, we differentiate the terms, resistance and tolerance, on the basis of the paraquat-exposure history. Five hypotheses have been evaluated in several species as potential mechanisms of paraquat resistance and/or tolerance. In a species, the mode of action may be due to 1) reduced quantities of paraquat absorbed through the leaf surface, 2) detoxification of paraquat caused by the enhanced paraquat-metabolic activity, 3) rapid sequestration reducing level of paraquat at the site of action in chloroplast, 4) alteration of site of action in photosystem I resulting in interruption of electron transport to paraquat, and 5) rapid enzymatic detoxification of superoxide and other toxic forms of oxygen.