• Ocean and Polar Research
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• v.26 no.4
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• pp.679-684
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• 2004

To determine if Antarctic krill employ body shrinkage as one of its overwintering mechanisms in the field, Euphauia superba and Euphausia crystallorophias were collected during fall and winter in and around Marguerite Bay through US Southern Ocean GLOBEC field programs during fall and winter 2001 and 2002. The relationships between the body length and weight of both krill species were exponentially correlated with no significant differences between the two species (p>0.05). The ratio between eye diameter and body length of individual krill was examined in an expectation that it could be used as an indicator of the body shrinkage as previously suggested by Shin and Nicol (2002). These ratios were significantly different between the two krill species. Especially, E . crystallorophias had bigger eyes than E. superba. In both krill species, eye diameters were highly correlated with body lengths (regression coefficients ${\geq}0.70$). For E. crystallorophias, no significant differences of the ratio of eye diameter/body length were detected between fall and winter. Even though the ratios for E. superba were seasonally varied, it was not clear whether body shrinkage was an actual and critical overwintering mechanism for the krill population found in this study area. These results suggest that some individuals of E. superba might experience the body shrinkage during a part of their liff, but this morphological index alone (eye diameter/body length) may be insufficient to unambiguously separate the shrunk krill from the non-shrunk ones in the field-collected animals.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.561-567
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• 2011

Cold tolerance of the native Rhododendron species which are on the verge of extinction in Korean nature were compared with the introduced species and its mechanism were studied physiologically with the investigation of the leaf angle, leaf curling, and photosynthetic activity. The degree of cold tolerance measured with the leaf burning after winter season was higher in the native species, Rhododendron brachycarpum and Rhododendron brachycarpum var. roseum than all the introduced species. 'Nova Zembla', an introduced species, showed high sensitivity to the low temperature. Changes in leaf angle by the low temperature were bigger in 2 native species and 'Parker's Pink' than the other introduced species and small comparatively in 'Nova Zembla' and 'Cunningham's White' cultivar. Leaf curling also occurred strongly in 2 native species by the low temperature. While, it was comparatively little and mild in the other introduced species. Therefore these results suggested that the leaf movement such as leaf angle change and curling adapted to the low temperature is positively related to the cold tolerance of 2 native species. By the way, such relationship is not explainable in the cold-sensitive 'Parker's Pink' cultivar showing comparatively stronger leaf movement. Photosynthetic activity measured before the winter season was high in the cold-tolerant R. brachycarpum and its recovery after winter season was faster in the 2 native species and the introduced 'Cynosure' cultivar than the other introduced species. They were the lowest in the most cold-sensitive 'Nova Zembla'. This phenomena occurred similarly even in the stomatal conductivity, suggesting that the movement of water from the roots to the leaves is better and then the leaf burning after winter season become small in the cold-tolerant species. The recovery of photosynthetic activity and stomatal conductivity was comparatively slower in the cold-sensitive 'Parker's Pink'. From the above results, leaf behavior adapted to the low temperature during the winter season and water movement to the leaves are related collectively to the cold tolerance represented as the leaf burning in the Rhododendron species is suggested.

• Proceedings of the KGS Conference
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• 2002.05a
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• pp.77-80
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• 2002

본 논문의 연구목적은, 우리나라 감자재배지역의 분포 특징과 그 중심지를 밝혀 보는데 있다. 이와 같은 목적을 위하여 감자가 외국에서 우리나라에 전파해온 경로와 한국 내에서 의 전파경로를 알아보고, 7개 지역의 감자재배지역의 특징, 우리나라 감자재배의 생산량, 재배면적, 재배농가, 각 시기별 감자 재배지의 중심지와 남한의 감자재배 중심지를 구하였다. 이와 같은 연구내용은 주어진 자연환경에 인간이 어떻게 적응해가면서 살아가는지를 공부하는 지리학의 전통적인 개념인 자연과 인간과의 관계를 이해하는데 도움을 줄 수 있을 뿐만 아니라, 초 중등학교 및 대학에서 공부하는 한국지리 교육과정의 학습자료로서 유용하게 쓰일 수 있을 것으로 기대한다. 연구방법은 문헌연구과 1970년부터 1995년까지의 전국의 시.군별 감자재배지역의 입지계수를 구하여 연구하였다. 그 결과를 요약하면 다음과 같다. 1. 감자가 한국에 처음으로 재배된 것은 1824년(조선조 순조24년) 인데, 전파과정을 살펴보면, 안데스산지의 페루(1500년대) $\longrightarrow$ 에스파냐(1532년) $\longrightarrow$ 중국(1650년) $\longrightarrow$ 한국(1824년)순으로 전파되어온 북방전래설과 영국의 감자가 1832년 충청도의 서산으로, 일본 감자가 1920년에 수원으로 전파되었다는 남방전래설이 있다 2. 감자는 한국 전 지역에서 재배되는 중요 농작물이다 그러나 우리나라의 지형이 남북으로 깊게 뻗은 반도국이므로 위도와 지형 차이에 따라 기온과 고도가 다르게 나타나는데, 이러한 자연적인 요인의 영향이 가장 큰 요인이 되어 고랭지 여름재배지역.중산간 봄재배지역.중부평야 봄재배지역 남부평야 봄재배지역 남부해안 2기작 재배지역.남부 겨울재배지역.제주 가을 월동재배지역 등 7개 지역으로 구분되어 재배된다. 3. 우리나라(남한)의 감자 재배지의 중심지는 강원도 고랭지 여름재배지역과 제주도 가을 월동재배지역, 소백산맥과 진안고원이 만나는 부근 산지지역의 남원군.구례군 거창군.고령군과 남해안의 밀양군.양산군이다. 강원도 지역과 제주도 두지역이 전테 재배면적의 52%를 점유하여 감자 재배지의 핵심지를 이룬다. 4. 한국 감자 재배지역 중심지의 지리적 특징은, 높은 산지지역의 산록완사면에 밭작물로 재배된다는 점과 교통이 불편한 지역으로서 도시화와 산업화 지역의 그늘 지역이 대부분이다. 강원도의 감자 재배지는 감자재배에 적합한 자연환경과 화전농업의 전통, 감자 재배기술의 전파, 중앙정부와 지방정부가 지원하는 각종 연구소 분포와 영농지도, 씨감자 생산과 협동조합의 판로 개척, 도로 개설과 포장 등의 인문지리적 요인이 영농조건을 개선하고 감자 판매를 위한 시장접근을 용이하게 하여, 남한 최대의 감자 재배지역을 형성하였다. 제주도는 산지지형과 따뜻한 기온으로 2기작이 가능하고, 감자가공 공장설립과 교통발달에 따른 육지 시장과의 접근이 용이해졌기 때문에 남한에서 2번째로 큰 감자재배지역이 되었다.(요약 및 결론에서 발췌)

• Journal of Ginseng Culture
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• v.3
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• pp.1-10
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• 2021

Panax ginseng (Ginseng or Korean ginseng) is one of the most important medicinal herbs in the world. We made a high-quality whole genome sequence of P. ginseng using 'Chunpoong' cultivar, which is the first cultivar registered in Korea Seed and Variety Service (KSVS) with relatively similar genotypes and superior phenotypes, representing approximately 3 Gbp and 60,000 genes. Genome sequence analyses of P. ginseng and related speciesrevealed the origin of Korean ginseng and the ecological adaptation of 18 Panax species around the world. Korean ginseng and American ginseng (P. quinquefolius) are tetraploid species having 24 chromosome pairs, while the other 16 species are diploid species with 12 chromosome pairs. Panax and Aralia are the closest genera belonging to the Araliaceae family that diverged approximately 8 million years ago (MYA). All Panax species evolved as shade plants adapting to cool climates and low light conditions under the canopy of deep forests from Southeast Asia such as Vietnam to Northeast Asia such as Russia approximately 6 MYA. However, through recurrent ice ages and global warming, most diploid Panax species disappeared due to the freezing winter, while tetraploid P. ginseng may have appeared by allotetraploidization, which contributed to the adaptation to cold temperaturesin Northeast Asian countries including the Korea peninsula approximately 2 MYA. American ginseng evolved by the adaptation of P. ginseng in Northeast America after the intercontinental migration 1 MYA. Meanwhile, most of diploid Panax species survived in high-altitude mountains over 1,600 meters in Southeast Asia because they could not endure the hot temperature and freezing cold. The genome sequence provides good basisto unveil the origin and evolution of ginseng and also supports practical gene chips which is useful for breeding and the ginseng industry.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.939-961
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• 2016

For effective conservation of endangered wild plants, it is necessary to understand their interactions with environmental factors in each habitat together with life traits of target species. First, the characteristics of their distribution were investigated followed by their monitoring for 4 years focusing on the habitats in the lagoon. Also, their life traits were compared including production of hibernacles, fruits, and seeds by the soil fertilization and light intensities. Next, the information on the species was secured by germination experiment using the generated seeds from the cultivation experiment. The habitat of Glaux maritima var. obtusifolia Fernald in Korea was located in the rear edge of the worldwide distribution and its four habitats were isolated and distributed far away each other. Two of them were located in small salt-marsh and fine sand estuaries formed in the rocky area of the seashore, and the other two were inhabited with the sandy soil in the lagoon which was connected by river-mouth to the sea. Glaux maritima var. obtusifolia Fernald tends to be distributed in the sites where the establishment and growth of the competitor were inhibited by salinity, periodic flooding, and lower layer of the soil to extend a roots. It maintained its population by recruitments of hibernacles and seedling. The production of hibernacle was assumed to be affected by the particle consist of the sand together with organic matters in the soil. Seedling recruitment was observed only in the salt-marsh area located in the rear sites of sand ridge where was the shore of the lagoon. Glaux maritima var. obtusifolia Fernald was observed to have different threatening factors by each population. Its population in Pohang seemed the sedimentation of fine sand which affected the recruitment of hibernacles had been eroded due to the construction of the coastal road. The population in Ulsan appeared rapid expansion of competitor and reduction of its distribution area due to the interruption of eluted water supplied to the habitat. On the other hand, the habitat in the lagoon maintained the population relatively stable. Especially, the population in Songji-ho was determined to be the most stable one. To sustain the population of Glaux maritima var. obtusifolia Fernald distributed in the lagoon, it is suggested that the wide ranged scale of conservational activities is necessary to maintain the mechanisms including the entrance of seawater which belongs to the lagoon, and periodic flooding.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.193-199
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• 2021

Solenopsis japonica, which is belonging to Formicidae in Hymenoptera, is a native ant species in Korea. However, it had not been studied for cold hardiness of S. japonica to understand on its overwintering mechanisms in field so far. Cold tolerance on developmental stages was measured at different cold temperature with various exposure times. Workers showed more survival at 5℃ and 10℃ compared with other stages and elevated cold tolerance when workers were exposed at 15℃ for more than 12h incubation as a rapid cold hardening (RCH) condition. RCH treatment not only increased survival of workers at cold temperatures, but also decreased supercooling point (SCP) and freezing point (FP). RCH group increased the survival rate by 44% at 10℃ compared with Non-RCH group. SCP and FP were depressed from -10.0 to -14.2℃ and from -11.3 to -15.3℃, respectively, after RCH treatment. Cold temperature increased expression level of cold- and stress-related genes such as glycerol kinase and heat shock protein. These results indicate unacclimated cold tolerance of S. japonica and its acclimation to low temperature by RCH.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.762-766
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• 2011

Cropping system is very important for environment conservation and improvement of nutrient recovery rates in agricultural land. This case study was conducted to identify the nutrient balance of major upland cropping types with different districts. Typical cropping systems at MuAn and HaeNam located in the south coast district were cultivated with soybean-chinese cabbage or garlic and garlic-soybean-chinese cabbage-hot pepper. Alpine district, PyeongChang was cultivated with double cropping of chinese cabbage and potato-radish or chinese cabbage for one year. Typical cropping type of AnDong, YeongYang where are well known for hot pepper cultivation was hot pepper's mono cropping and hot pepper-soybean or hot pepper-sesame for one year. But SeoSan and HongSeong, where are located in mid-west coast had variety cropping system compareed to other districts. Double cropping of chinese cabbage, a heavy fertilizing crop, caused higher nutrient balance in the field when it was cultivated consistently. Experiment showed that heavy fertilizing crops, such as chinese cabbage, garlic and onion, need to be rotated with soybean and sesame cultivation which need smaller fertilizer level. Alpine arable land has shown higher nutrient balance than other areas, and the introduction of rotation crops are needed to reduce nutrient balance and environmental protection.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.133-138
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• 2012

This study was conducted to investigate the herbicidal activity against resistant biotype on sulfonylurea (SU) herbicides such as Scirpus juncoides and Monochoria vaginalis at the glasshouse and paddy rice cultivation area. In order to investigate resistance breakability against SU-resistanted annual weeds, new rice herbicides containing tefuryltrione [p-hydrophenyl pyruvate dioxygenase (HPPD) inhibitor] were tested. In both lab test and field experiment, tefuryltrione mixture, 4-HPPD inhibitor had shown excellent efficacy with a bleaching on the leaves of resistant annual weeds at early time after treatment and showed excellent persistance. Especially, tefuryltrione mixture had shown excellent controlling effect on annual and perennial SU-resistant S. juncoides in the regional field experiment. In phytotoxicity test, this tefuryltrione mixture had shown good selectivity to common rice species.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.545-572
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• 2011

The genetic diagnosis methods by RT-PCR and Virion capture (VC)/RT-PCR against Rice stripe virus (RSV) were developed. Three diagnosis methods of seedling test, ELISA and RT-PCR were compared in virus detection sensitivity (VDS) for RSV. The VDS of ELISA for RSV viruliferous small brown plant hopper (SBPH) was higher with 40.5% than that of seedling test. The VDS of RT-PCR was higher with 21% than that of ELISA. The VDS of ELISA and VC/RT-PCR was same with 9.2% in average on the SBPH collected from fields at the areas of Gimpo, Pyungtaeg and Sihueng, Gyeonggi province in 2009. The specific primers of RSV for SBPH and rice plant were developed for the diagnosis by Real time PCR. The RQ value of Real time PCR for the viruliferous and non viruliferous SBPH was 1 for 50 heads of non viruliferous SBPH, 96.5 for 50 heads of viruliferous SBPH, 23.1 for 10 heads of viruliferous SBPH + 40 heads of non viruliferous SBPH, and 75.6 for 30 heads of viruliferous SBPH + 20 heads of non viruliferous SBPH. The RQ value was increased positively by the ratio of viruliferous SBPH. Full sequences of 4 genomes of RSV RNA1, RNA2, RNA3 and RNA4 were analysed for the 13 RSV isolates from rice plants collected from different areas. Genetic relationships among the RSV isolates of Korea, Japan and China were classified as China + Korea, and China + Korea + Japan by phylogenetic analysis for RSV RNA1 and RNA2. In case of RNA3 involved in pathogenicity, genetic relationship of RSV among the three countries was grouped into 3 as China, China + Korea, and Korea + Japan. According to the genetic relationships in RSV RNA4, RSV isolates were grouped into 4 as China, Korea, China + Korea + Japan, and Korea + Japan. Viruliferous insect rate (VIR) of RSV in average increased in each year from 2008 to 2010, and the rates were 4.3%, 6.1%, and 7.2%, respectively, at the 28 major rice production areas in 7 provinces including Gyeonggido. The highest VIR in each year was 11.3% of Gyeonggido in 2008, 20.1% of Jellanamdo in 2009 and 14.2% of Chungcheongbukdo in 2010. The highest VIR depending upon the investigated areas was 22.1% at Buan of Jellabukdo in 2008, 36% at Wando and Jindo of Jellanamdo in 2009, and 30.0% at Boeun of Chungcheongbukdo in 2010. Average population density (APD) of overwintered SBPH was 13.1 heads in 2008, 13.9 heads in 2009 and 5.6 heads in 2010. The highest APD was 39.1 and 60.4 heads at Buan of Jellabukdo in 2008 and 2009, respectively, and 14.0 heads at Pyungtaeg of Gyeonggido. The acreage of RSV occurred fields was 869 ha in the western and southern parts, mainly at Jindo and Wando areas, of Jellanamdo in 2008. In 2009, RSV occurred in the acreage of 21,541 ha covered whole country, especially, partial and whole plant death were occurred with infection rate of 55.2% at 3,025 plots in 53 Li, 39 Eup/Myun, 19 Si/Gun of Gyeonggido, Incheonsi, Chungcheongnamdo, Jeollabukdo and Jeollanamdo. Seasonal development of overwintered SBPH was investigated at Buan, Jeollabukdo, and Jindo, Jeollanamdo for 3 years from 2008. Most SBPH developed to the 3rd and 4th instar on the periods of May 20 to June 10, and they developed to the adult stage for the 1st generation on Mid and Late June. In 2009, all SBPH trapped by sky net trap were adult on May 31 to June 1 at Mid-western aeas of Taean, Seosan and Buan, and South-western areas of Sinan and Jindo. The population density of adult SBPH was 963 heads at Taean, 919 at Seocheon and 819 at Sinan area. The origin of these higher population of adult SBPH were verified from the population of non-overwintered SBPH but immigrant SBPH. From Mid May to Mid June in 2010, adult SBPH could not be counted as immigrant insects by sky net trap. The variation of RSV VIR was high with 2.1% to 9.5% for immigrant adult SBPH trapped by sky net trap at Hongsung of Chungcheongbukdo, Buan of Jeollabukdo and so forth in 2009. The highest VIR for the immigrant adult SBPH was 9.5% at Boryung of Chungcheongnamdo, followed by 7.9% at Hongsung of Chungcheongnamdo, 6.5% at Younggwang of Jeollanamdo, and 6.4% at Taean of Cheongcheongnamdo. The infection rate of RSV on rice plants induced by the immigrant adult SBPH cultivated near sky net trap after about 10 days from immigration on June 12 in 2009 was 84.6% at Taean, 65.4% at Buan and 92.9% at Jindo, and 81% in average through genetic diagnosis of RT-PCR. Barley known as a overwintering host plant of RSV had very low infection rate of 0.2% from 530 specimens collected at 10 areas covering whole country including Pyungtaeg of Gyeonggido. Twenty nine plant species were newly recorded as natural hosts of RSV. In winter annual plant species, 11 plants including Vulpia myuros showed RSV infection rate of 24.9%. The plant species in summer annual ecotype were 13 including Digitaria ciliaris with 44.9%, Echinochloa crusgalli var. echinata with 95.2% and Setaria faberi with 65.5% in infection rate of RSV. Five perennial plants including Miscanths sacchariflorus with infection rate of 33.3% were recorded as hosts of RSV. Rice cultivars, 8 susceptible cultivars including Donggin1 and 17 resistant ones including Samgwang, were screened in field conditions at 3 different areas of Buan, Iksan and Ginje in 2009. All the susceptible cultivars were showed typical symptom of mosaic and wilt. In 17 genetic resistant cultivar, 12 cultivars were susceptible, however, 5 cultivars were field-resistant plus genetic resistant to RSV as non symptom expression. When RSV was artificially inoculated at seedling stage to 4 cultivars known as genetic resistant and 3 cultivars known as genetic susceptible, the symptom expression in resistant cultivars was lower as 19.3% in average than that of 53.3% in susceptible ones. In comparison of symptom expression rate and viral infection rate using resistant Nampyung and susceptible Heugnam cultivars by artificial inoculation of RSV at seedling stage, the symptom expression of Heugnam was higher as 28% than 12% of Nampyung. However, virion infection of resistant Nampyung cultivar was higher as 12% reversely than 85% of susceptible Heugnam. Yield loss of rice was investigated by the artificial inoculation of RSV at the seedling stage of resistant cultivars of Nampyung and Onnuri, and susceptible cultivars of Donggin1 and Ungwang for 3 years from 2008. The average yield per plant was 7.8 g, 8.5 g and 13.8 g on rice plants inoculated at seedling stage, tillering stage and maximum tillering stage, respectively. The yield loss rate was increased by earlier infection of RSV with 51% at seedling stage, 46% at tillering stage and 13% at maximum tillering stage. In resistant rice cultivars, there was no statistically significant relation between infection time and yield loss. In natural fields on susceptible rice cultivar of Ungwang at Taean and Jindo areas in 2009, the yield loss rate was increased with same tendency to the infection hill rate having the corelation coefficient of 0.94 when the viral infection was over 23.4%.

• Korean journal of applied entomology
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• v.55 no.1
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• pp.17-26
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• 2016

Climate change has been regarded as one of main factors to change Korean insect pest fauna. Especially, a global warming model predicts to expand habitat for insect pests originated from tropical or subtropical regions. Two insect pests, the beet armyworm (Spodoptera exigua) and the diamondback moth (Plutella xylostella), are known to overwinter in some greenhouse conditions without diapause induction in Korea. There was a clear difference between these two insects in seasonal occurrence. P. xylostella occurred only at early spring and fall seasons, but did not occur during summer. In contrast, S. exigua maintained their occurrence from late spring to fall seasons. This study set up a hypothesis that the difference in the seasonal occurrence may be resulted from variation in susceptibility to high temperature. To test the hypothesis, heat tolerance was compared between these two insects. Exposure to $42^{\circ}C$ for 40 min killed 100% individuals of P. xylostella larvae. However, most larvae of S. exigua survived in response to $42^{\circ}C$ even for 80 min. Heat tolerance varied among developmental stages in both insects. Highest tolerant stages were $4^{th}$ instar larvae and adults for P. xylostella, but $1^{st}$ instar larvae for S. exigua. Pre-exposure to $37^{\circ}C$ for 30 min significantly increased heat tolerance in both insects. Induction of heat tolerance accompanied with significant increase of glycerol contents in the hemolymph in both insects and up-regulation of three heat shock protein expressions in S. exigua. These results suggest that the differential susceptibility to high temperature explains the disappearance of P. xylostella during summer, at which S. exigua maintains its occurrence.