• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.59-68
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• 2009

Single-dose toxicity test of germanium-fortified lettuce was investigated in mice. Both sexes of C57BL/6 mice were orally administered once at a dose of 2,000 mg/kg. No death, clinical signs and pathological findings related to the treatment were observed. In addition, no significant changes in feed consumption and body weight gain were obtained during the treatment period, in spite of day-to-day fluctuation of water consumption. There were no considerable changes in hematology and serum biochemistry, except a significant decrease in GPT, GOT and LDH. Several alterations were observed in organ weight and blood biochemistry, including thymus, ovaries, heart, kidney and platelet in male or female mice. The ability of spleen cells proliferation was almost same level as shown in control group. However the population of B cells, helper T cells and cytotoxic T cells was not comparably changed in all groups. Taken together, it is suggested that single oral dose of germanium-fortified lettuce to C57BU6 mice did not cause apparent toxicological change at the dose of 2,000 mg/kg body weight.

• Korean Journal of Environmental Biology
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• v.28 no.1
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• pp.30-39
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• 2010

We researched community structure, species composition, and habitat environment of Dendropanax morbifera populations distributed in Goheung, Haenam, Wando (I.), and Bogildo (I.) at south coast of the Korean Peninsula. Our research was also estimated possible area for growth of Dendropanax morbifera by analyzing meteorological factors of the habitat thereof. Dendropanax morbifera community divided into Castanopsis cuspidata var. sieboldii group and Carpinus laxiflora group by difference of species composition. Broad-leaved evergreens showed high dominance value in view of rNCD in Dendropanax morbifera community as follows: Camellia japonica (100.0), Quercus acuta (88.6), Castanopsis cuspidata var. sieboldii (55.8), Dendropanax morbifera Lev. (41.4), Trachelospermum asiaticum var. intermedium (23.8), Eurya japonica (19.9) and Ligustrum japonicum (11.5). In the population distribution, 94.2% of Carpinus laxiflora group consisted of sapling and small size class that are less than 5 cm in DBH while 54.2% of Castanopsis cuspidata var. sieboldii group did. The soil environment of habitat showed low soil acidity, good organic matter and water content, and good drainage. The distribution area of Dendropanax morifera habitat had $13^{\circ}C$ or more in annual mean temperature, $7.4^{\circ}C$ or more in daily minimum temperature, $100^{\circ}C$ month or more in warmth index, and approximately 1,344 mm in mean annual precipitation. Dendropanax morifera habitat corresponded to evergreen broad-leaved forest zone located in islands and coast in the southwest region of the Korean Peninsula. The northern limit line of Dendropanax morifera community was determined as Gunsan-Jeongeup-Gwangju-Jinju-Pohang-Youngdeok line based on $13^{\circ}C$ in annual mean temperature that was confirmed in natural habitat of Dendropanax morifera community.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.361-364
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• 2016

Waterbirds using rice fields has increased due to a decline of natural wetlands. The rice field is an essential habitat to supports the waterbird population. Although use of rice field by waterbirds has been widely documented, little information is available on distribution patterns of waterbirds under the pesticide use in rice fields. The current study conducted to understand the relationship between habitat use by waterbirds and pesticide applicatioins in rice fields. We monitored the distribution of waterbirds at Daeho reclaimed area in July 2013 to June 2014 and September 2014 to August 2015. As a results, three heron species (Black-crowned Night Heron Nycticorax nycticorax, Eastern Cattle Egret Bubulcus coromandus and Intermediate Egret Egretta intermedia) are more sensitive to pesticides use than other waterbird species in rice fields. Future studies are necessary to explore the relationship between bird's distribution and management practices including pesticide use at different spatiotemporal scales.

• The Plant Pathology Journal
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• v.21 no.1
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• pp.33-38
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• 2005

Changes of control efficacy of chemical to potato late blight caused by Phytophthora infestans in potato fields from 2001 to 2004 were examined. Control efficacy of metalaxyl was suddenly decreased from 100% in 2002 to 50% in 2004 and that of dimethomorph also was similar to those of metalaxyl. However, the control efficacy of ethaboxam no great change. Both A1 and A2 mating type isolates were isolated from 2001 to 2004 in several areas in Korea. The majority of the P. infestans isolates were A1 mating type. Total 939 isolates of P. infestans obtained from several areas in Korea from 2001 to 2004 were examined for changes of sensitivity to metalaxyl. Frequencies of metalaxyl resistance isolates were gradually increased from 17% in 2001 to 84.2% in 2004, but isolation frequencies of metalaxyl sensitive and intermediate resistant isolate were decreased. Cause of decreasing control efficacy of metalaxyl was thought by increase of resistance isolates in A1 mating type population according to increasing metalaxyl use. Most isolates were grown at 0.5 ${\mu}g/ml of dimethomorph and isolates grown at 1 ${\mu}g/ml of dimethomorph were approximately 10.2-22.9%. However, no isolate was able to grow at 5.0 ${\mu}g/ml. Based on these results, minimum inhibitory concentrations (MIC) of dimethomorph to P. infestans were determined to be 0.5-1.0 ${\mu}g/ml. Our results indicated that the reason decreasing control efficacy of dimethomorph was not caused by occurrence of resistant isolates. About 5% and 12.1% isolates among the total isolates collected in 2003 and 2004 were grown on V-8 juice rye agar containing 1.0 ${\mu}g/ml ethaboxam. The 2.1 and 25.4% isolates had MICs of 0.2-0.4 ${\mu}g/ml, and MIC values of 87.9% and 74.3% isolates were less than 0.2 ${\mu}g/ml concentrations of ethaboxam. Therefore, resistance development by P. infestans to ethaboxam is not likely to occur in the natural condition.

• Research in Plant Disease
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• v.24 no.1
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• pp.9-25
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• 2018

Plant viruses cause significant yield losses and continuously threaten crop production, representing a serious threat to global food security. Studies on plant-virus interactions have contributed to increase our knowledge on plant immunity mechanism, providing new strategies for crop improvement. The prophylactic managements consist mainly following international legislations, eradication of infected plants, and application of pesticide to decrease the population of vectors. Hence, putting together the pieces of knowledge related to molecular plant immunity to viruses is critical for the control of virus disease in fields. Over the last several decades, the outstanding outcomes of extensive research have been achieved on comprehension of plant immunity to viruses. Although most dominant R genes have been used as natural resistance genes, recessive resistance genes have been deployed in several crops as another efficient strategy to control viruses. In addition, RNA interference also regulates plant immunity and contribute a very efficient antiviral system at the nucleic acid level. This review aims at describing virus disease on crops and summarizes current resistance mechanisms. Furthermore, we will discuss the current biotechnological approaches to control viral diseases and the future questions that are to be addressed to secure crop production against viruses.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.235-240
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• 2014

Recently, the consumption of duck meat has been gradually increased in Korea. However, most of the duck breeds in Korea were imported from overseas. Based on the large demands for the breeding stocks of native ducks, a new project for the commercial use of the Korean native ducks has been launched. For the initial investigation of the relationships between Korean native duck (KND) with other duck breeds, the sequences from D-loop control region in mitochondrial DNA (mtDNA) was used. The results from phylogenetic analysis indicated that both KND and White Commercial Duck (WCD) breeds were classified well with wild duck breeds. However, mallard duck was not discriminated well with KND. The haplotype analysis indicated that KND and WCD have eight different haplotypes with eleven SNPs. Three haplotypes (haplotype 1, 3, 4) were shared both in KND and WCD. On the other hand, haplotype 1 was appeared only KND and haplotype 5, 6, 7, 8 were identified only in WCD population. With further verifications, the results presented here can be used for the conservation and commercialization of the Korean native ducks.

• Journal of Environmental Science International
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• v.18 no.4
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• pp.463-471
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• 2009

A study on vegetation in the Mangyeong River and Dongjin River basins and the surrounding regions of the Saemangeum Reclaimed Land was conducted in a series of efforts to determine the expected ecological changes in the salt marshes, to restore their vegetation, to explore the restoring force of halophyte, to examine the community mechanism and, ultimately, to rehabilitate marshy land vegetation along the lakeside, coastal dune and salt marshes of the Saemangeum Project Area. The findings of the study may be summed up as follows: Five species such as Suaeda japonica, Salicornia herbacea, Atriplex gmelini, Aster tripolium and Suaeda asparagoides that are mostly distributed in the estuary of the Saemangeum Reclaimed Land were analyzed to examine the mechanism of halophyte to maintain their community. To find out the strategies of plants for survival and the cause of forming community structure, a research was made as for appearance ratio of biomass, root lengths and germination. With regard to biomasses of halophyte, the biomass of Suaeda japonica increases rapidly, while Salicornia herbacea adopts a strategy of unstable growth pattern by which the biomass increases slowly in parallel with its slow speed of growth since initial appearance of young sapling. In contrast, Suaeda asparagoides, Atriplex gmelini and Aster tripolium choose to adapt themselves to environment promptly by being transformed into life form of annual or biennial plant, a pattern that is presumed to be favorable and stable for survival in the later stage of growth. In short, there is a sharp distinction among the 5 species: i.e. Suaeda japonica that begins to grow fast in the length of surface and underground section but slows down from the mid-stage on; Salicornia herbacea that grows slowly in the beginning step but starts to step up from the middle onward; Atriplex gmelini and Aster tripolium growing slowly in the initial stage but fast later on; and Suaeda asparagoides that turns from the constant growth in the beginning to rapid growth in the later period. The outcomes of the analysis into status of growth and influencing factors of Suaeda japonica in the sowing field that is most widely prevalent in the Saemangeum Reclaimed Land as a sort of ecological pioneer in the salt marshes showed that the average size of grass lands, density and number of individuals increase in the natural sowing field as well as in the plowing field regardless of their physical as well as physico-chemical features of the soil as the season progresses from June to October of a year.

• Journal of the Korean Geographical Society
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• v.43 no.1
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• pp.87-103
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• 2008

The geographical name is an expression of human knowledge about living conditions and a basic tool for understanding about regional cultures and history as a result of spatiotemporal changes. This study aims to understand the historical and regional characteristics by analyzing the frequency and distribution of geographical names of 1:50,000 topographic map in the early 20th century and materializing on electronic cultural atlas. The result of this analysis is as follows. First, the aspect of distributed geographical names on the Korean Peninsula reflects a general trait of the country's natural and human environment included geographical features, population, arable land, the number of counties and villages, and functions of administration and military, etc. Second, through the frequency and weight of their names, the analysis shows not only the change of native names, but also the country's phase of the time by Japanese colonial policies such as exploitation of resources, the construction of railroads, and a desire to control of the border area with Manchuria. In addition, the study identified regional characteristics and differences in environmental perception and preferences, and naming basis and forms by the comparative analysis of each type of geographical names associated with village and ridge such as 'Chi' 'Ryung' 'Duk' 'Hang' 'Pyeong' 'Gok'. In particular, those characteristics were largely affected from environmental difference of each area.

• Journal of the Korean Geographical Society
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• v.49 no.6
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• pp.849-864
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• 2014

The objective of this paper is to investigate both the processes of regional policy and their determinants of the International Garden Exposition Suncheon Bay Korea 2013(IGEXPO 2013). IGEXPO 2013 was held in Suncheon from April to October 2013, and almost 440 million tourists visited to IGEXPO 2013. The processes of regional policy of the IGEXPO initiative were divided into four stages; the first stage from 1992 to 2002 was a beginning of conservation movement for Suncheon Bay; the second stage from 2003 to 2007 was a constructing of natural ecological park of Suncheon Bay; the third stage from 2008 to 2010 was a beginning of IGEXPO initiative and a confirming of the IGEXPO 2013; the four stage from 2011 to 2013 was a preparing and holding of IGEXPO 2013. The major determinants related to regional policy development process of IGEXPO initiative are the population n movement for Suncheon Bay, the rergional development strategy for central city in Gwangyang Bay area, the leadership for continuity of regional policy oriented to environmental and ecological city, and the cooperation and competition relationalship with neighboring city, in particular Yeosu city and 2012Yeosu EXPO planning. IGEXPO 2013 has been evaluated as having some performances such as the enhancement of city image, establishment of city park as a public goods, and formation of community leadership promoting continuous urban policy for environmental & ecological city.

• Journal of The Korean Association For Science Education
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• v.35 no.4
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• pp.691-707
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• 2015

This study aims to develop biology teachers' education program based on argumentation activity about core concepts of evolution and to analyze the characteristics of core concepts of evolution learned during the program. The eight core concepts of evolution in this study were variation, heritability of variation, competition, natural selection, adaptation, differential reproductive rate of individuals, changes in genetic pool within a population, and macroevolution. The performances of teachers participating in the program were compared before and after argumentation activities; consisting of seven sessions on the eight core concepts of evolution. The process of the program was specially designed by learning cycle model for teacher education, consisting of seven phases: identification of the task, production of a tentative argument, small group's written argument, share arguments with the other groups, reflective discussion, final written argument, and organization by an instructor. Participants in the study were two pre-service biology teachers and four in-service biology teachers. The results suggest that biology teachers reduced the teleological explanation for biological evolution and improve its adequacy after the intervention. Teachers lacked the opportunity to discuss variation, heritability of variation, competition, and macroevolution because science textbooks lack information on the concepts of biological evolution. The results of this study suggest that because the argumentation program developed for teachers helps to improve understanding the concepts of evolution and to reduce inadequate conceptions in biology, teacher education programs using argumentation activity and eight core concepts of evolution will play a role for efficient evolution education for biology teachers.