Southern Region Of South Korea Research Articles

Fungal Diversity in Nam River and Their Biodegradative Activities

145 fungal isolates were obtained from three sampling sites situated within the Nam River basin, located in the southern region of South Korea. Through ITS sequence analysis, the fungal isolates were identified to comprise 55 species of ascomycetes and 11 species of basidiomycetes. The 55 species of ascomycetes exclusively belong to the phylum Pezizomycotina, comprising 33 species of Dothideomycetes, 6 species of Eurotiomycetes, and 16 species of Sordariomycetes. Regarding their plant pathogenicity, an investigation into the fungi’s ability to penetrate solid media revealed Nigrospora chinensis as displaying the highest growth, followed by Pseudopestalotiopsis theae, various Curvularia species, Diaporthe species, and Alternaria alternata. Further research associating this penetration ability with fungal pathogenicity is deemed necessary. Among the 10 fungal species exhibiting penetration abilities, an examination of their capability to degrade biological polymers revealed that two strains of D. phaseolorum displayed exceptional polymer degradation. These strains exhibited remarkable abilities in decomposing malachite green and crystal violet, both recalcitrant dyes. This study underscores the potential utilization of fungal diversity in freshwater environments as a foundational approach to address freshwater pollution issues.

Effect of climate change‐induced increases on the range of rice‐barley double cultivation on the intermediate egret

Abstract Intensification of cultivation methods and land‐use types, particularly in the face of climate change, has steadily weakened the habitat function of rice fields for waterbirds. Intermediate egrets (Ardea intermedia) are highly dependent on rice field habitats. Here, we examine the effect of a shift from rice monoculture to rice–barley double cultivation on the use of rice fields by intermediate egrets in South Korea. Rice–barley double cultivation has been increasing steadily in the southern region of South Korea due to changes in the rice growth period under climate change and maximization of economic benefits. We studied rice fields to determine the effect of the rice–barley double cultivation area on the abundance of intermediate egrets on the regional scale and their potential distribution pattern in response to double cultivation in relation to climate change using national‐scale climate, altitude and land cover data from 1 May to 23 June 2018. Compared to the irrigation practices used for rice monoculture, irrigation was stopped for some time in rice–barley double cultivation prior to planting, compromising the role of rice fields as a food ground for intermediate egrets. The potential abundance of intermediate egrets rapidly decreased by half when the double cultivation area increased to >40% of the total rice‐field area, and was less than one individual if the area increased to >80%. Furthermore, according to climate change projections, by 2100, the double cultivation area would account for 75.74% of the predicted range of intermediate egret foraging ground. Synthesis and applications. Double cultivation areas should be <40% of existing rice fields to minimize the impact of the change in cultivation practices. This approach can also convert rice fields to other types of land use. Consequently, appropriate conservation and management measures may be developed to maintain suitable habitats despite rapidly changing cultivation practices resulting from climate change.

지리정보시스템과 통계기법을 이용한 고농도 미세먼지 오염특성 파악: 동남권과 남부권 우심지역 사례 연구

지리정보시스템과 통계기법을 이용한 고농도 미세먼지 오염특성 파악: 동남권과 남부권 우심지역 사례 연구

Influencing of the Building Energy Policies upon the Efficiency of Energy Consumption: The Case of Courthouse Buildings in South Korea

As Korea has declared to realize a net-zero emission by 2050 in the Paris Agreement, the country has begun to implement national energy efficiency policies through the Green Standard for Energy and Environmental Design (G-SEED) certification and revision of building insulation thickness standard. However, some studies have reported the ineffectiveness of G-SEED certification and insulation thickness standard in reducing the energy consumption in certain buildings. Therefore, this study investigated the effectiveness of G-SEED certification and the revision of buildings’ insulation thickness standard, and evaluated the energy consumption of courthouse buildings. In addition, this study investigated the total annual energy consumption (electricity, gas, and heating energy) per gross floor area of courthouse buildings located in the central and southern regions of South Korea. Although many studies about the energy consumption analysis of non-residential buildings have been performed previously, a study evaluating the effectiveness of green certification and building insulation thickness standard on the energy consumption of courthouse buildings was performed for the first time. The results revealed that the revision of building insulation thickness standard and G-SEED certification resulted in an energy consumption efficiency of 34.61 and 31.14%, respectively. These results indicated the effectiveness of G-SEED certification and the revision of the building insulation thickness standard for enhancing energy efficiency in Korean courthouse buildings. However, some negative results were observed in the southern area, indicating that it is essential to increase the effectiveness of the building insulation thickness standard and G-SEED certification implementation.

First report of Labyrinthula zosterae (Labyrinthulomycetes) as the causal pathogen of wasting disease in the seagrass Zostera marina in Korea.

Zostera marina L. plants have been seriously impacted by wasting disease along the Atlantic coasts of North America and Europe since the 1930s (Muehlstein 1989). Sudden declines in the population sizes of Zostera marina affect primary and secondary producers of different trophic levels in blue carbon ecosystems (Gleason et al. 2013). Muehlstein et al. (1991) first identified Labyrinthula zosterae (Labyrinthulomycetes) as the pathogen causing wasting disease in Zostera marina. However, there have been no reports of wasting disease pathogens affecting seagrass in Korea. In this study, we collected leaves of Z. marina showing symptoms of wasting disease in the southern region of South Korea (Dongdaeman, Namhae, Gyeongnam Province) during field monitoring (from April to September 2013). The pathogens of wasting disease, Labyrinthula zosterae has been isolated from the infected leaves of Z. marina and established as a culture strain (Supplementary Figure 1). Samples of Z. marina and L. zosterae were deposited at the Fisheries Seed and Breeding Research Institute (previous Seaweed Research Center, National Institute of Fisheries Science, South Korea). Microscopic examination of the infected leaf tissues revealed fusiform or spindle-shaped vegetative Labyrinthula cells (4-5 × 15-20 μm). These were similar in size and shape to those previously described for Labyrinthula species. The fusiform cells were cultured in 1% serum seawater agar medium, and they formed colonies and showed gliding motility along a network of hyaline slime filaments. To validate the pathogenicity, re-inoculation tests by L. zosterae were performed with the isolated strains in accordance with Koch's postulates. Healthy leaves of Z. marina collected from the field were used in the re-inoculation tests and were cultured at 15°C under white fluorescent irradiation of approximately 20 μmol·photons·m-2·s-1 and a 12:12-h light:dark cycle (Supplementary Figure 1). Labyrinthula zosterae re-isolated from artificially infected leaves of Z. marina was confirmed by DNA sequence similarity analysis. Total genomic DNA from the infected leaf cells and the culture strains was extracted using the QIAamp DNA Stool Mini Kit (Qiagen, Germany). Internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA were determined to identify Labyrinthula species. L. zosterae-specific primers (Lz2forward (5'- CTAAGACTAAACGAGGCGAAAGCCTAC-3') and Lz2reverse (5'-AGGTTTACAAAACACACTCGTCCACA-3') in Bergmann et al. (2011)) were used to confirm the infection of L. zosterae in the leaves from the field samples and the re-inoculation test samples. Next, PCR products were cloned using a pLUG-Prime® TA-cloning Vector (iNtRON Biotechnology, Korea) and commercially sequenced (SolGent, Korea). The ITS sequence of Korean L. zosterae (accession number MW357748) showed high sequence similarity (99.3-100%) with that of L. zosterae deposited in GenBank (National Center for Biotechnology Information) from BLAST searches. These findings confirm that this is the first report of L. zosterae as the causal pathogen of wasting disease in Z. marina in Korea.

Defensive behavior of the invasive alien hornet Vespa velutina nigrithorax against potential human aggressors

AbstractIn areas where wasps are common, many wasp sting incidents occur. However, guidance on the correct response to wasp attacks remains lacking. In this study, behavioral response experiments were conducted with the aim of minimizing damage from group wasp attacks. The study species was Vespa velutina, which frequently causes wasp sting injuries in the southern regions of South Korea. Results demonstrated that worker wasps showed defensive behavior when a person approached within 3 m of the nest, and the attack rate was higher when the person conducted a large arm swing. When a person walked away after touching a nest, the number of workers attacking did not significantly decrease until they reached 5 m, this reduced to less than half when the person reached 10 m. Approximately 1.3 workers attacked even up to 300 m. However, when the person ran, the number of workers attacking was almost one or less after 10 m. Therefore, it is best to escape quickly to at least 10 m to reduce injury from group attacks. When wasps attacked, even if the person crouched, the attack did not decrease. Our recommended defensive behavior when wasps attack unexpectedly is that victims should turn their face in the opposite direction to the nest or the wasps, protect their face with their hands and arms, lean forward and run away rapidly to minimize injury. Wearing a wide brim hat was very effective, preventing about 75% of stings to the head, so this is also recommended.

제주 및 남해안 편백의 수간곡선식 및 입목수간 재적표 개발

제주 및 남해안 편백의 수간곡선식 및 입목수간 재적표 개발

Representing the Unrepresentable in South Korean Activist Performances

On 16 April 2014, the Sewol Ferry capsized in the southern region of South Korea: 304 passengers died, including 250 high school students. Despite an international outcry, there has not yet been a comprehensive investigation into what caused the Sewol to sink and why the passengers were not rescued promptly. This article discusses how performance can represent something that defies explanation because we do not know how or why it happened. Yellow Ribbon’s Talent Show, Namsan Arts Centre’s From Pluto, and Camino de Ansan performed the role of the students who died. Taking these three case studies, this article analyzes the ways in which they strive to represent the unrepresentable as they attempt to document the sinking and achieve justice, while memorializing the victims and arguing for the necessity of a more safety-conscious society. Areum Jeong is Assistant Professor in Humanities at Sichuan University-Pittsburgh Institute. Jeong’s research takes a transnational approach to Korean and Korean-American film, literature, theatre, and performance. Her current book project explores how performance documents death, loss, and memory in South Korean and diasporic communities.

Assessment of genetic diversity and population structure among a collection of Korean Perilla germplasms based on SSR markers.

Information on the genetic variation of genetic resource collections is very important for both the conservation and utilization of crop germplasms in genebanks. Var. frutescens of Perilla crop is extensively cultivated in South Korea as both an oil crop and a vegetable crop. We used SSR markers to evaluate the genetic diversity, genetic relationships, and population structure of 155 accessions of var. frutescens that have been selected as genetic resources for the development of leaf vegetable cultivars and preserved in the RDA-Genebank collection from South Korea. A total of 155 accessions of var. frutescens of Perilla crop collected in South Korea were obtained from the RDA-Genebank of the Republic of Korea. We selected 20 SSR markers representing the polymorphism of and adequately amplifying all the Perilla accessions. The average GD and PIC values were 0.642 and 0.592, respectively, with ranges of 0.244-0.935 and 0.232- 0.931. The genetic variability in the southern region of South Korea was higher than that in the central region. The clustering patterns were not clearly distinguished between the accessions of var. frutescens from the central and southern regions of South Korea. These results regarding the genetic diversity and population structure of the 155 accessions of var. frutescens of South Korea provide useful information for understanding the genetic variability of this crop and selecting and managing core germplasm sets in the RDA-Genebank of the Republic of Korea.

Assessment of Inter-Model Variability in Meteorological Drought Characteristics Using CMIP5 GCMs over South Korea

Although many studies have sought to characterize future meteorological droughts, a few efforts have been done for quantifying the uncertainty, inter-model variability, arises from global circulation models (GCM) ensemble. A clear understanding of the uncertainty in multiple GCMs should be preceded before future meteorological droughts are projected. Therefore, this study evaluates the uncertainty in future meteorological drought characteristics that are induced by GCM ensemble using the custom measure “the degree of GCM spreading”. Future meteorological drought indices, the standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI), were computed to five different time scales: 3, 6, 9, 12 and 24 months using statistically downscaled 28 GCMs under Representative Concentration Pathway (RCP) 4.5 and 8.5 at 60 weather stations in South Korea. The frequency, duration, and severity of drought events were estimated for three different future periods; F1 (2010–2039), F2 (2040–2069), and F3 (2070–2099). It was found that the uncertainty increases as the time scale lengthens regardless of a choice of drought indices or RCP scenarios. It also turned out that the SPI exhibits larger uncertainty rather than the SPEI, because temperature data exhibit a relatively much smaller variability comparing to precipitation data. Moreover, there was a shift of regions having larger values of the increasing rate between F1 and F2, which is shift from the north-western to southern region of South Korea.

First Report of Oat Halo Blight Caused by Pseudomonas coronafaciens in South Korea

In May 2019, halo blight symptoms were observed on leaves of oats (Avena sativa L. ‘Joyang’) at the tillering stage. Plants were cultivated in experimental fields in Wanju County (latitude 35.842006°, longitude 127.049588°), located in the southern region of South Korea. Symptoms consisted of water-soaked spots, which progressed into blotches or streaks with brown oval to spindle-shaped centers surrounded by yellow halos. These symptoms were similar to those reported for oats infected by Pseudomonas coronafaciens in other parts of the world (Haber and Harder 1992; Harder and Harris 1973; Wilkie 1972). To isolate the causal agent of the symptoms, 1- to 3-cm-long pieces of symptomatic leaves from 10 different oat plants were surface sterilized with 70% ethanol for 30 s and macerated in sterile distilled water. The macerates were streaked onto nutrient agar plates and grown at 28°C for 48 h. In total, four pure colonies were selected and were cream-colored, wet, and shiny, with convex surfaces. The isolated colonies did not produce fluorescent siderophores when cultured on King’s medium B. We selected two representative colonies (SP-1 and X-1) for further characterization. The 16S rRNA, gyrB, and rpoD loci were amplified using the primers 27F/1492R (Lane 1991), gyrB+271ps/gyrB-1022ps, and rpoD+147p/rpoD-1222ps, respectively (Sarkar and Guttman 2004). The sequences were deposited in GenBank with the following accession numbers: MN134544 (SP-1) and MN134571 (X-1) for the 16S rRNA gene, MN599033 (SP-1) and MN599034 (X-1) for the gyrB gene, and MN599035 (SP-1) and MN599036 (X-1) for the rpoD gene. Analyses of these sequences indicated that the two isolates belong to the same clade of pathotypes as P. coronafaciens. These pathotypes formed a clade distinct from that of other P. syringae pathovars, as described recently by Dutta et al. (2018). For confirmation, PCR analysis with two different specific primer sets was performed. The 498-bp products from SP-1 and X-1 were amplified using a specific primer pair for P. coronafaciens, Pc-12-F and Pc-12-R (An et al. 2015), and 600-bp products with primers, P1 and P2, to detect the sequence within the plasmid pCOR1 harboring the genes for toxin production (Dutta et al. 2018). Consequently, the bacteria isolated from the lesions on the oat plants were P. coronafaciens strains. To fulfill Koch’s postulates, pathogenicity tests were conducted in which isolates SP-1 and X-1 were inoculated onto surface-sterilized leaves of 2-week-old, disease-free, greenhouse-grown Joyang oat plants. Leaves were inoculated using a 1-ml needle syringe with 400 µl of a bacterial suspension (10⁸ CFU/ml) or 400 µl of sterile water (for the control group). The plants were incubated for 1 week at 23°C in 100% relative humidity under a 10-h photoperiod. After 5 days, the inoculated leaves began to exhibit typical brown necrotic spots surrounded by yellow halos. Bacteria were isolated from these diseased leaves, and the 16S rRNA gene sequences of the isolates were the same as those from the blighted field-grown leaves. The pathogenicity test was repeated twice. These findings indicated that P. coronafaciens strains accounted for the symptoms observed in field-grown oats. To the best of our knowledge, this is the first report of oat halo blight disease caused by P. coronafaciens in South Korea. The pathogen has the potential to impair plant health and result in economic losses, as reported for other global locations (Elliott 1920; Harder and Harris 1973; Wilkie 1972).

Effects of shift in growing season due to climate change on rice yield and crop water requirements

According to recent climate projections for South Korea, increases in temperature and precipitation will affect water use and crop production associated with paddy rice cultivation. Impacts are expected on crop growing season, crop varieties, and farming methods, all of which are highly vulnerable to disruption in weather conditions. Previous studies have estimated the effects on agricultural water resources according to climate change scenario, but most do not consider the growing season. In this study, changes in paddy rice yield and agricultural water requirement are estimated based on the impact of shift in growing season using a crop growth model. Future weather trends for four selected study areas in central and southern regions of South Korea were constructed using the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios developed by the UN Intergovernmental Panel on Climate Change, and the paddy rice yields were simulated using the Crop Environment Resource Synthesis–Rice growth simulation model. Weather, soil, crop data, cultivars, and experimental data were used as model inputs. The results show a delay in the optimal transplanting date in 2100, with the date in the RCP 8.5 scenario delayed rapidly compared with the delay in RCP 4.5. In addition, paddy rice yield and growing period decrease. Consumptive water use and irrigation requirements decrease in the RCP 4.5 scenario due to increased rainfall. However, in RCP 8.5, less precipitation falls during the growing period, leading to an increase in irrigation requirements in some regions. These results are expected to be useful for paddy water management and growing season adjustment and to help establish long-term food security policies.

The relationship among meteorological, agricultural, and in situ news-generated big data on droughts

The purpose of this study is to evaluate the effectiveness of agricultural drought risk management using news media data (NMD) by elucidating the relationships among the standardized precipitation index (SPI), the agricultural reservoir storage deficit index (RDI), and the NMD obtained from news sources. For a severe drought that occurred in South Korea from 2014 to 2016, the SPI and RDI were calculated, and the NMD were collected. In drought-affected areas, the receiver operating characteristic (ROC) was used to assess the performance of NMD and to replicate the temporal drought trends using the SPI and RDI. The ROC analysis of NMD and drought indices showed a hit rate above 0.65, and the hit rate showed the highest value (0.75) in SPI-12. The central region of South Korea showed the highest number of news postings during the 12 months in which SPI-12 remained in the severe drought category. For the southern region of South Korea, large amounts of NMD were collected when the RDI had the lowest value. The amount of NMD was sensitive to spring drought from March, the delayed Jangma in late June, the dry Jangma in July, and the absence of a typhoon in September of 2015. The study results showed that NMD are closely related to both meteorological drought and agricultural drought conditions. As NMD represent the in situ drought experienced by the people, these data can provide a useful drought indicator along with government-published drought information.

Prescription patterns of anti-rheumatic drugs in patients with rheumatoid arthritis at a community pharmacy near a secondary-care hospital in South Korea

Rheumatoid arthritis (RA), one of the most common forms of inflammatory disease, induces chronic inflammation of the joints and various organs. Therapy with disease-modifying anti-rheumatic drugs (DMARDs) should be initiated immediately after a diagnosis of RA because the early initiation of DMARDs can prevent joint damage in a large proportion of RA patients. The aims of this study were to analyze the prescription patterns of RA medication in Korean patients visiting a community pharmacy and to examine drug-drug interactions (DDIs) between DMARDs and concomitant medications. A retrospective study was conducted with RA patients visiting the community pharmacy, located at the southern region of South Korea, between January and February 2015. Data were collected through the review of patients’ prescriptions. During the study period, 931 were diagnosed with RA. Methotrexate (MTX), hydroxychloroquine (HCQ), leflunomide (LEF), tacrolimus (TAC), and sulfasalazine (SUL) were prescribed to 703 (75.51%), 387 (41.57%), 303 (32.55%), 131 (14.07%), and 83 (8.92%) patients, respectively. The most commonly prescribed combination was DMARDs+glucocorticoids (GCs) (40.79%). MTX and TAC showed drug interactions with non-steroidal anti-inflammatory drugs (NSAIDs) and proton pump inhibitors (PPIs), but significant DDIs between HCQ or LEF and co-administered drugs were not found. MTX was the most commonly prescribed DMARD for both monotherapy and in combination with other DMARDs. The commonly prescribed DMARDs (i.e., MTX and TAC) were demonstrated to have DDIs with NSAIDs and PPIs. Therefore, the co-administration should be carefully monitored, especially in elderly patients with polypharmacy.

Use patterns of over-the-counter (OTC) medications and perspectives on OTC medications among Korean adult patients with chronic diseases: gender and age differences.

BackgroundA number of symptomatic patients tend to use over-the-counter (OTC) medications and prescription medications. OTC medications can be easily obtained in pharmacies for self-treatment, but using OTC medications is not always safe and beneficial for patients. The aims of this study were to examine the use patterns of OTC medications and assess patients’ perspectives regarding the use of OTC medications in Korean patients with chronic diseases.Patients and methodsA descriptive, cross-sectional survey was carried out with Korean patients who visited the community pharmacy, located at the southern region of South Korea, during September 2015.ResultsA total of 345 patients participated in this survey. Approximately 64% of Korean survey respondents reported that they had used OTC drugs. The most commonly used OTC medications were antipyretics, analgesics and anti-inflammatory drugs. The perception level of Korean consumers on adverse drug reactions and drug–drug interactions from OTC medications was relatively low. Although OTC package leaflets are a main source of information about OTC medications, Korean consumers’ level of reading OTC package leaflets was relatively low.ConclusionBased on these results, this study can serve as a meaningful starting point for interventions of health care professionals regarding OTC medications in South Korea. In particular, pharmacists should inform their consumers of drug-related problems from OTC drugs during consultation with the consumers; however, information about OTC drugs should be tailored to consumer information needs with the consideration of his or her circumstance. It is somewhat difficult to generalize the results from this study to other regions of South Korea since most of the respondents were probably residents of a small rural city located in the southern region of South Korea.

Anti-skin ageing effects of phenolic compounds from Carpinus tschonoskii

Carpinus tschonoskii (CT) is distributed through in southern regions of South Korea. Six known compounds, including three ellagitannins, one gallotannin, and two flavonoids were isolated from CT. In conclusion, the tannins, especially ellagitannins, and CT extract showed potent anti-oxidative, anti-inflammatory and anti-skin ageing activities.

Molecular Epidemiology of Viral Conjunctivitis in the Southern Region of South Korea, 2012–2016

Molecular Epidemiology of Viral Conjunctivitis in the Southern Region of South Korea, 2012–2016

Evolution and geographic effects of high-speed rail in East Asia: An accessibility approach

The rapid development of high-speed rail (HSR) is influencing regional development, regional structure, commuting, and regional integration. East Asia is the region with the world’s first and largest current operating and planned HSR network. In this paper, we examine the evolutionary mechanism and impacts on the transport circle and accessibility of HSR in East Asia. The results indicate that the HSR network first follows a “core-core” model and then forms a corridor in Japan, South Korea, and China Taiwan, but then forms a complete network in China Mainland. The current operating HSR lines are mostly distributed in regions with developed economies and dense populations, and more than half of the population and GDP in China can be served by HSR within 1 hour’s travel time. The planned HSR network will expand to the western region of China and Japan and the southern region of South Korea. The development of the current operating and planned HSR network considerably enlarges the transport circle of core cities, especially cities along trunk HSR lines. This 1 h transport circle of core cities has formed continuous regions in the Yangtze River Delta, the Pearl River Delta, Tokyo, Seoul, and along trunk HSR lines. The HSR network will bring about substantial improvement in accessiblity, but also increase the inequality of nodal accessibility in China Mainland. Spatially, the spatial patterns of the weighted shortest travel time of cities in China Mainland, Japan, and South Korea all present the “core-peripheral structure”, taking Zhengzhou, Tokyo, and Seoul, respectively, as core cities, and cities located along the trunk HSR lines gain large improvement in accessibility.

반유한 직립형 동부의 하우스 파종기 이동에 따른 농업적 형질의 변화

The purpose of this study was to investigate the effects of sowing time on ecological responses, growth, and yields of cowpeas grown in plastic greenhouses in a southern region of South Korea. Experiments were carried out in Naju, Jeonnam Province (Latitude 04` N, Longitude 54` E) during 2012 and 2013. The intermediate-erect type strains used in this study were Jeonnam1 and Jeonnam2. Sowing was performed between mid-March and mid-August at intervals of one month. The days from sowing to emergence was significantly higher for the mid-March sowing (12 days) but no significant differences were observed among the other sowing dates (3 to 4 days). The days from sowing to first flowering were shorter for sowing dates between mid-March and mid-July because sowing time was delayed and then were lengthened again at mid-August sowing; the days were longest at mid-March sowing (around 75 days) and were shortest at mid-July sowing (30 days). The days from first flowering to harvesting were short for the sowing dates between mid-March and mid-May (24 to 28 days) but were relatively long for subsequent sowing dates (35 to 38 days). Stem and peduncle lengths were relatively long for the mid-April and mid-August sowing dates. Main-stem node number was highest for the mid-June sowing. Branch number per plant was highest for the mid-March sowing. The mid-March sowing displayed the highest number of pods per plant as well as the heaviest seed weight. Yield per 10 ares was highest for the mid-March sown Jeonnam1 and the Jeonnam2 strains (340 and 367 kg respectively), and then tended to decrease due to subsequent delays in sowing.

Modeling Methodology for Cold Tolerance Assessment of Pittosporum tobira

Abstract: This study was carried out to develop a simple, rapid and reliable assessment model to predict cold tolerance in Pittosporum tobira, a broad-leaved evergreen commonly used in the southern region of South Korea, which can minimize the possible experimental errors appeared in a electrolyte leakage test for cold tolerance assessment. The modeling procedure comprised of regrowth test and a electrolyte leakage test on the plants exposed to low temperature treatments. The lethal temperatures estimated from the methodological combinations of a electrolyte leakage test including tissue sampling, temperature treatment for potential el ectrical conductivity, and statistical analysis were compared to the results of the regrowth test. The highest temperature showing the survival rate lower than 50% obtained from the regrowth test was -10°C and the lethal was -10°C~-5°C. Based on the results of the regrowth test, several methodological combinations of electrolyte leakage tests were evaluated and the electrolyte leaka ge lethal temperatures estimated using leaf sample tissue and freeze-killing method were closest to the regrowth lethal temperatur e. Evaluating statistical analysis models, linear interpolation had a higher tendency to overestimate the cold tolerance than non- linear regression. Consequently, the optimal model for cold tolerance assessment of P. tobira is composed of evaluating electrol yte leakage from leaf sample tissue applying freeze-killing method for potential electrical conductivity and predicting lethal temp erature through non-linear regression analysis.Additional key words: