• Korean Journal of Weed Science
• /
• v.14 no.3
• /
• pp.163-170
• /
• 1994

The experiment was conducted in 1993 to find out a simple prediction method of weeds and to make the prediction models of weeds in paddy fields. The annuals producing fine seeds were apt to emerge at sampling soil only, on the contrary the perennials and the annuals producing large seeds tended not to emerge at sampling soil due to the miss of seeds at sampling. There was no appropriate regression between a total number of weeds emerged at sampling soil and that of weeds occurred in fields. The important annual weeds occurring in fields were able to predict by the number of weeds emerged at sampling soil, but it was difficult to predict the important perennial weeds. In case of Bidens tripartita producing large seeds and Eleocharis kuroguwai producing large tubers, the prediction coefficients were high as above 1.0, and that of Echinochloa crus-galli and Sagittaria pygmaea were comparatively high as 0.175 and 0.172, respectively. However the coefficients of the other weeds were much low as below 0.08. The prediction models for 9 species were made. The model of six species including E. crus-galli, M. vaginalis, R. indica, B. tripartita, E. triandra and S. pygmaea were linear regression with high significance, however that of 3 species including C. difformis, S. juncoides and E. kuroguwai were curve regression with high significance.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.14 no.4
• /
• pp.196-206
• /
• 2012

Studies of seasonal changes in $C_3/C_4$ mixed communities are rare, particularly in Asian summer monsoon climate zones. In our present study, seasonal changes in the profile and coverage of $C_3$ and $C_4$ plants were investigated in 2009 in Haenam, Yeongdong and Cheorwon regions of South Korea (all at different latitudes). The aim was to estimate the impacts of temperature and sunshine duration on species composition and transition timing of the $C_3$ and $C_4$ plants. From our results, the number of $C_3$ plants was found to increase from early spring to mid-May, and then decrease again until September in the Haenam and Yeongdong regions, but continuously increase from early spring to September in the Cheorwon region under relatively low summer temperatures. On the other hand, the number of $C_4$ plants increased from June or July to September in all three regions. These seasonal changes in species number and ratio have a direct impact upon species diversity which is highest when there are no dominant species. The relative coverage and relative summed dominance ratio (SDR') of the $C_3$ plants decreased from spring to autumn, but increased for the $C_4$ plants during this time in an exponential fashion with increasing accumulated temperature and sunshine duration. The transition timing from $C_3$ to $C_4$ plants occurred when the sum of sunshine duration for the days with daily mean temperature above $5^{\circ}C$ was 1017 hrs for the SDR'.

• Restorative Dentistry and Endodontics
• /
• v.30 no.5
• /
• pp.409-422
• /
• 2005

The aim of this study was to identify the bacteria isolated from acute endodontic lesions by cell culture and 16S rDNA sequencing. The necrotic pulpal tissue was collected from 17 infected root canals, which were diagnosed as being either an acute pulpitis or acute periapical abscess. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ul of 1 XPBS. The sample solution was briefly mixed and plated onto a BHI-agar plate containing $5\%$ sheep blood. The agar plates were incubated in a $37^{\circ}C$ anaerobic chamber for 7 days. The bacteria growing on the agar plate were identified by 16S rRNA coding gene (rDNA) cloning and sequencing at the species level. Among the 71 colonies grown on the agar plates, 56 strains survived and were identified. In dental caries involving the root canals, Streptococcus spp. were mainly isolated. Actinomyces, Clostridia, Bacteroides and Fusobacteria were isolated in the periapical lesion without dental caries. Interestingly, two new Actinomyces spp. (ChDC B639 and ChDC B631) were isolated in this study. These results showed that there was diversity among the species in endodontic lesions, This suggests that an endodontic infection is a mixed infection with a polymicrobial etiology. These results may offer the bacterial strains for pathogenesis studies related to an endodontic infection.

• Korean Journal of Environment and Ecology
• /
• v.26 no.1
• /
• pp.74-81
• /
• 2012

Decay rate and nutrient dynamics during leaf litter decomposition of deciduous Quercus acutissima and evergreen Quercus mysinaefolia were studied for 24 months from December 2008 to December 2010 in Gongju, Chungnam Province, Korea. Percent remaining weight of Q. acutissima and Q. mysinaefolia leaf litter after 24 months elapsed was $46.3{\pm}5.4%$ and $37.8{\pm}2.5%$, respectively. Decomposition of evergreen Q. mysinaefolia leaf litter was significantly faster than that of deciduous Quercus acutissima leaf litter. Decay constant(k) of Q. acutissima and Q. mysinaefolia leaf litter after 24 months elapsed was 0.38 and 0.49, respectively. Initial C/N and C/P ratio of Q. mysinaefolia leaf litter was significantly lower than those of Q. acutissima leaf litter. Initial C/N and C/P ratio of Q. acutissima leaf litter was 46.8 and 270.9, respectively. After 24 months elapsed, C/N and C/P ratio of decomposing Q. acutissima leaf litter decreased to 22.5 and 104.2, respectively. Initial C/N and C/P ratio of Q. mysinaefolia leaf litter was 22.4 and 41.7, respectively. After 24 months elapsed, C/N and C/P ratio of decomposing Q. mysinaefolia leaf litter decreased to 16.7 and 89.7, respectively. Initial concentration of N, P, K, Ca and Mg in leaf litter was 8.31, 0.44, 4.18, 9.38, 1.37 mg/g in Q. acutissima, and 19.88, 2.73, 7.06, 8.24, 2.61 mg/g in Q. mysinaefolia, respectively. Initial concentration of N and P in Q. mysinaefolia leaf litter was significantly higher than those in Q. acutissima. After 24 month elapsed, remaining N, P, K, Ca and Mg were 100.91, 114.75, 32.99, 50.63, 15.51% in Q. acutissima, and 43.22, 11.35, 12.98, 82.22, 44.23% in Q. mysinaefolia, respectively. N and P in decomposing leaf litter was immobilized in Q. acutissima, and mineralized in Q. mysinaefolia.

• Journal of Bio-Environment Control
• /
• v.24 no.2
• /
• pp.51-56
• /
• 2015

The objective of this study was to evaluate the effect of silicate fertilizer on growth, physiology and abiotic stress tolerance of Chinese cabbage seedlings. Five silicate concentrations (8, 16, 32, 64, and 128mM) and control (non-treatment) were applied to Chinese cabbage seedlings twice a week. Three weeks after application of silicate treatment, seedlings were used for treating abiotic stresses and were assessed for growth and physiological characteristics. Growth parameters significantly increased in 8, 16, and 32mM treatments except 64 and 128mM. Total root surface area, total root length, and number of root tips increased in 8, 16 and 32mM treatments, but they decreased in treated seedlings with 64 and 128mM of silicate. The highest growth parameters and root morphology were observed in 8mM treatment. As for the effect on the seedling physiology, transpiration rates decreased while stomatal diffusive resistance increased to increasing silicate concentration. The application of silicate reduced the electrical conductivity, heating and chilling injury index at high and low temperatures. Silicate enhanced drought tolerance of Chinese seedlings by delaying the starting time of wilting point. The starting time of wilting point in the control was 3 days after discontinuation of irrigation, while in the 8, 64 and 128mM of silicate treatments were 4 days, and the 16 and 32mM treatments were 5 days. All plants were wilted after 5 days in control without irrigation whereas it showed in 8mM treatment after 6 days, in 16, 32, 64, 128mM treatments after 7 days.

• Korean Journal of Environment and Ecology
• /
• v.24 no.6
• /
• pp.723-734
• /
• 2010

This study aims to analyze the change in vegetation for 10 years after the construction, targeting Suwoncheon, the first domestic ecological stream construction project. As for the section for the study, the section from Gyeonggi bridge to Youngyeon bridge, the first restoration project section, was targeted. The research districts consisted of 3 districts depending on topographical structure. Investigation check cosisted of cross-sectional topographical structure, vegetation status and the structure of herbaceous plant community. As for the cross-sectional topographical structure of the stream, the width of entire stream was 26.5~28.0m and water channel is 10~20m. The area for hydrophilic space was securing spacious riverside. Upper stream of reservoir beam was shallow and slow in reservoir area above weir. Lower stream of reservoir beam, the width of water channel was narrow and ripples were formed. Among species, 9 plants were planted and 6 species plants including Salix gracilistyla, Phragmites communis and Zoysia japonica were planted at the time of construction. In the water side, there were 2 species, such as Zoysia japonica and Trifolium repens, etc, still remained after seeding at the time of constrcution. The planted plants which were observed through this investigation, were 2 species such as Festuca arundinacea and Dactylis glomerata. Apart from the planted plants, arid climate herbaceous plant such as Setaria viridis and Artemisia princeps var. orientalis formed power and the naturalized species variously emerged in 15 species. For revetment, natural stone stacking method was condicted and Salix gracilistyla, Aceriphyllum rossii, etc were planted. But all the planted plants disappeared and now it was covered with Equisetum arvense and Humulus japonicus. It was because that the base for growth and development of the plants was not constructed at the time of restoration in a way of attaching natural stones onto the concrete base. In the water channel, various wetland species including Typha orientalis, Acorus calamus var. angustatus and Phragmites communis, etc, were planted but only Salix gracilistyla, Phragmites communis and Zizania latifolia remained. As for species of the autochthons, Persicaria thunbergii was dominant. In the lower stream of reservoir beam, Humulus japonicus formed forces. In the hydrophilic space, it was necessary to direct the landscape of in-stream vegetation in cosideration of users. For this, planting Miscanthus sacchariflorus in a community was proposed. In the upper stream of reservoir beam, suplementary screen seeding was necessary so that Zizania latifolia, Typha orientalis and Phragmites communis can fit the depth of water. In the Lower stream of reservoir beam, it was necessary to constantly manage Humulus japonicus so that the wetland autochthons species, such as Phragmites communis and Persicaria thunbergii can establish power more stably.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.2
• /
• pp.121-129
• /
• 2014

Marine algal flora and community structure were seasonally investigated at four sites in the vicinity of the Igidae on the southern east coast of Korea from May 2010 to February 2011. A total of 66 species including 9 of Chlorophyta, 14 of Phaeophyta, 43 of Rhodophyta were found during the survey period. Among these species, 16 species were found throughout the year. Seasonal mean biomass in wet weight was 123.6 (spring), 2,061.6 (summer), 412.0 (autumn), 678.9 (winter) $g{\cdot}m^{-2}$. Maximum biomass was recorded in summer($2,061.6g{\cdot}m^{-2}$), and minimum was recorded in spring($123.6g{\cdot}m^{-2}$). Spatial maximum and minimum species number were recorded at station 3 and 4(50 species) and at station 1(47 species). At station 1, 2 directly exposure on Yongho and Daeyeon cheon (stream) run off, and discharge from Nambu sewage treatment plants near coastal area, species diversity was relatively low and dominant species were similar throughout four seasons. The R/P, C/P and (R+C)/P value reflecting flora characteristics were 3.07, 0.64 and 3.71, respectively. The flora investigated could be classified into six functional groups such as coarsely branch form 39.39 %, sheet form 30.30 %, thick leather form 13.64 %, filamentous form 12.12 %, crustose form 3.03% and jointed calcareous form 1.52 % during survey period. The number of marine algae species in Igidea were 96 species at 1996 to 1997 and 66 species at 2010 to 2011, respectively. The change of seaweed species is due to the pollution loaded from sewage treatment plant and stream. We thus recommend that the positive maintenance control method like sewage treatment, for the protection of seaweed bed should be proceeded to near coastal area.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.42 no.2
• /
• pp.33-40
• /
• 2014

The purpose of this study is to examine vegetation of the outer walls of the Jeongyi Town Wall in Jeju and analyze the characteristics and problems identified, for suggesting preliminary data for selecting species of plants appropriate for the greening of the walls in the southern temperate climate region, including Jeju. The result of this study is as follows. The number of plants growing naturally around the walls of the town was identified to be 52 taxa. Based on the list of naturalized plants, there are 5 taxa; Sonchus oleraceus, Houttuynia cordata, Crassocephalum crepidioides, Erigeron annuus and Lamium purpureum. The number of species by district was from 3 to 14 taxa with 7.1 taxa on average. Analyzing by the constancy class, plants in class III included Sedum bulbiferum, Trichosanthes kirilowii, Hedera rhombea and Boehmeria nivea. Manipulation of the species composition table shows that the number of plant species growing naturally around the walls of Jeongyi Town Wall is a total of 52 taxa, including 11 taxa by differential species of community and 41 taxa by companion species. The types of plants very useful for the covering of the walls are evergreen climbing vine, such as Hedera rhombea, Ficus thunbergii and Euonymus fortunei and deciduous climbing vine, such as Parthenocissus tricuspidata, Trichosanthes kirilowii and Paederia scandens. In addition, Ficus stipulata is identified as a vegetation more appropriate for the southern-ward lattice-blocked walls. Woody plants, such as Akebia quinata, Celastrus flagellaris, Ampelopsis brevipedunculata for. citrulloides, Rubus hirsutus, Clematis apiifolia and herbaceous plants, such as Dioscorea tenuipes, D. quinqueloba, D. nipponica, Cayatia japonica and Paederia scandens var. angustifolia are highly useful materials for climbing plants for covering the walls of the southern province. Pteridophyte, such as Lemmaphyllum microphyllum, Pteris multifida, Cyrtomium falcatum and Lygodium japonicumare suggested as very useful for increasing unique regional characteristics of the southern province, including Jeju.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.36 no.2
• /
• pp.1-10
• /
• 2018

This study aims to find out the characteristics of the vegetation landscape characteristics and system which led the formation of the urban image in Jeonju in the late Joseon period connected with urban spatial structure, using designated as treasure No. 1586 which was made in the middle of 18C. The vegetation landscape characteristics of Jeonju in the late Joseon Dynasty derived from the analysis of are summarized as follows. Firstly, the vegetation landscape system in Jeonju is composed of the natural vegetation around mountain area of Jeonju-Buseong, the independent vegetation or cluster planting forests linked with the main facilities, the Bibo-Forests connected with topographical characteristics of Jeonju, and the vegetation combined with a private garden. Secondly, planting landscape was specialized using flag species and local species. Thirdly, the garden-type plantation centered on the back yard or front of main facilities, with the background of natural vegetation landscape combined with the mountain area and the vegetation combined with a private garden, dominates vegetation landscape of Jeonju Buseong as objects. Fourthly, in order to overcome the defects of topographical characteristics, the Bibo-Forests were emphasized as an important planting landscape element in addition to the vegetation landscape elements connected with main facilities. Fifth, ecological vegetation landscape technique was taken considering the topographical characteristics. The characteristics of vegetation landscape of Jeonju Buseong, which is derived from , have an important meaning to restore and reproduce Jeonju's historical features. Especially, the vegetation communities of the non-booming concept combined with the geographical features, the ecological landscape harmonizing with the topography, the round house type landscape mixed with the private house, and the specialization of vegetation landscape using local species are important factors in securing the city image based on the historical characteristics and creating a city brand that utilizes vegetation landscape.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.44 no.4
• /
• pp.1-13
• /
• 2016

To detail a picture of the economic value of Miscanthus landscape conservation in terms of cultural services aspects of Ecosystem Services, Sunghaksan(Mt.), Hwawangsan(Mt.) and Jaeyaksan(Mt.), which are known for their Miscanthus colonies, were chosen as survey sites. After examining the willingness to pay for the value of Miscanthus landscape conservation by targeting of visitors each study area, the economic value of Miscanthus landscape conservation per capita aspects was evaluated using Contingent Valuation Methods(CVM) from the collected willingness to pay for economic value of Miscanthus scenery by site. After using the target Chi-square test to analyze the differences among each site, the correlation between specific variables was investigated. Willingness to pay for the Miscanthus landscape conservation was found to increase as the respondents' income became higher. The more environmental conservation efforts were being made in their daily life, the higher willingness to pay was for Miscanthus landscape conservation. Likewise in other studies, the higher the bid was, the less willingness to pay was. The per capita assessment of the Miscanthus landscape value of the logit models in the dual estimated using the factor extracted with each of the injected variable bounds was estimated for Seunghaksan (\38,277), Hwawangsan(\38,648), and Jaeyaksan(\48,891). The average of the three sites was estimated to be \38,679. Assessment of the economic value of these Miscanthus landscape sites saw high willingness to pay by visitors when compared to the current market price inflation, such as watching movies or amusement park admission, which could mean that visitors recognize the value of ecosystem services from nature in evaluating the Miscanthus landscape.