• Journal of Wetlands Research
• /
• v.22 no.2
• /
• pp.100-105
• /
• 2020

Northern pipevine (Aristolochia contorta) commonly inhabits marginal areas between waterside and terrestrial vegetation. In particular, A. contorta is ecologically important in the marginal areas as a food plant of dragon swallowtail butterfly (Sericinus montela), which is designated as vulnerable species in the Republic of Korea. For long-term sustainability of the plant population, assessment of the genetic diversity of exist populations should be conducted. Genomic DNA of A. contorta leaf samples were extracted from four populations where the vigorous growth were observed in the South Korea. Intra-population genetic diversity and inter-population genetic distance were assessed using randomly amplified polymorphic DNA (RAPD) with five polymorphic random primers. Overall genetic diversity was lower, compared to other wetland species (h: 0.0607 ~ 0.1401; I: 0.0819 ~ 0.1759), while GP showed the highest intra-population genetic diversity. Despite of the geographical distance, GP showed the larger genetic distance from other populations. This result seemed to be caused by the fragmented habitat and lower sexual reproduction of A. controta. Mixture of the different source populations and construction of the proper environmental condition such as shade and physical support for sexual reproduction should be considered for conservation of A. contorta population.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.1
• /
• pp.96-103
• /
• 2015

The effects of $CO_2$ concentration, nutrient levels, and irradiance on the growth of germlings and juveniles, and on the photosynthesis of adults were examined in a green tide alga, Ulva australis. We used a factorial experimental design with two $CO_2$ concentrations (380 and 750 ppm), two nutrient levels (control and PES medium), and two irradiance levels (50 and $100{\mu}mol$ photons $m^{-2}s^{-1}$). Germlings grew best ($664.15{\pm}61.45{\mu}m$ in length) under conditions of 750 ppm, PES, and $100{\mu}mol$ photons $m^{-2}s^{-1}$ after 10 days in culture. Relative growth rates (RGR) of the juveniles were greatest (4.41% $day^{-1}$) under conditions of 750 ppm, PES, and $50{\mu}mol$ photons $m^{-2}s^{-1}$ after 5 days in culture. Photosynthetic efficiency ($F_v/F_m$) of the adult discs was $0.73{\pm}0.05$ before the experiment and reached a maximum ($0.83{\pm}0.01$) under conditions of 750 ppm, control, and $50{\mu}mol$ photons $m^{-2}s^{-1}$ after 5 days in culture. Growth (germlings and juveniles) and photosynthesis (adult discs) of Ulva australis increased when $CO_2$ levels were 750 ppm. Additionally, the optimal irradiance for growth and photosynthesis differed among stages, wherein germlings grew best at $100{\mu}mol$ photons $m^{-2}s^{-1}$, juveniles grew best at $50{\mu}mol$ photons $m^{-2}s^{-1}$, and adults photosynthesized most at $50{\mu}mol$ photons $m^{-2}s^{-1}$. The performance of Ulva australis at all examined life stages was enhanced under the PES nutrient treatment. In conclusion, the physiological responses of U. australis to varying $CO_2$, nutrient, and irradiance levels differed slightly among life stages. However, growth and photosynthesis always increased with elevated $CO_2$ and nutrient concentrations. These results indicate that U. australis green tide blooms might occur more frequently in coastal areas if $CO_2$ and nutrient concentrations increase.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.3
• /
• pp.254-261
• /
• 2012

To reduce the injury by continuous cropping of sweet potato (Ipomoea batatas (L.) Lam.), the farmer's plant and virus-free plant were cultivated with the density of $70{\times}25cm$ (June 10, 2011) in continuous cropping soil (CCS) and subsoiling reversion soil (SRS). Fertilizer was applied at the rates of 55-63-156 $kg\;ha^{-1}$ ($N-P_2O_5-K_2O$) and 10 $ton\;ha^{-1}$ of cattle manure in CCS, and it was applied the 50% increased cattle manure compost and nitrogen in DRS. Symptoms of viral infection were revealed in the farmer's plant at 30 days after planting, but there were no symptoms in virus-free plant. The yield of virus-free plant was more increased 15% and 10.5% than that of farmer's plant in DRS and CCS, respectively. The yield of sweetpotato in SRS was more increased 8.8% and 3.2% in farmer's plant and virus-free plant compared to CCS, respectively. In DRS, the rate of marketable tuber of virus-free plant was increased by 80% compared to the farmer's plant (60.1%). The virus-free plant was produced the tuber with more brilliant peel color and well-formed shape compared to the farmer's plant. The increased yield of virus-free plant and in SRS soil condition showed a positive relationship (p=0.05) with the number of leaf per plant at 30 days and the number of branch per plant at 120 days after planting. The results showed that the early growth after planting was very important for the development of storage root. Therefore, the deep-subsoil reversion and cultivation of virus-free plant could be reduced the injury by continuous cropping of sweet potato, and increased farm income.

• Research in Plant Disease
• /
• v.15 no.3
• /
• pp.175-182
• /
• 2009

We investigated the effect of the infection times and infection degrees at transplanting time of Zucchini yellow mosaic virus (ZYMV) on the growth and yield of cucumber plants at the semi-forcing and the retarding culture in 2007. When cucumber was inoculated with ZYMV at transplanting time, 15, 30, 45, 60, and 75 days after transplanting, vine length, internode length, number of leaf of the plants and marketable yield largely decreased as the cucumber infected earlier. The regression models were obtained between the disease incidence levels at 20 days after transplanting as the inoculation degrees and the marketable yield of cucumber: y = $9333.1e^{-0.0317x}$ ($R^2$ = 0.8946) at the semi-forcing culture and y = $14695e^{-0.0303x}$ ($R^2$ = 0.8735) at the retarding culture. And the cucumber yield loss regression models between the symptoms incidence days from the final harvesting time and the rates of yield decrease were expressed as y=1.0851x - 6.7067 ($R^2$ = 0.9567) at the semi-forcing culture andy=1.0439x + 2.1321 ($R^2$ = 0.9674) at the retarding culture.

• Journal of Life Science
• /
• v.24 no.12
• /
• pp.1325-1329
• /
• 2014

Gugija (Lycii chinese Miller) is traditionally consumed as a Chinese medicinal material in food, tea, or alcoholic beverages. Gugija has beneficial healthy components, but it produces an off-flavor during storage. This study compared the flavor components of fresh-dried Gugija and stale-dried Gugija. The flavor compounds in one fresh sample (sample 1) and one stale sample (sample 2) were extracted by the simultaneous distillation and extraction method. The concentrated aroma extracts were analyzed and identified by gas chromatography-mass spectrometry. Forty-five compounds, including 17 aldehydes, 8 alcohols, 6 terpene compounds, 4 esters, 3 ketones, and 3 pyrazines, were isolated in sample 1. Thirty-four compounds, including 12 aldehydes, 3 alcohols, 5 terpene compounds, 2 esters, 3 ketones, 3 pyrazines, and 1 acid, were isolated in sample 2. The main aroma components of sample 1 were 2-methyl butanal, 2-methyl propanol having sweet odor, and hexanal, (Z)-3-hexenol having grass odor, and phenyl acetaldehyde, benzyl alcohol having floral odor, and alkyl pyrazines having nutty odor. These compounds were decreased in sample 2, and several compounds containing isovaleric acid, which has a disagreeable, rancid-cheese odor were found newley.

• Research in Plant Disease
• /
• v.13 no.1
• /
• pp.61-65
• /
• 2007

English ivy (Hedera helix) in Araliaceae family is an evergreen climbing vine. A severe bacterial disease of English ivy was observed and investigated in January 2005. Initial symptoms on the leaves appeared as small water-soaked lesions on the lower surface. As the spots enlarged, the center became brown to brownish black and greenish-brown water-soaked, irregular margins surrounded the center, The spots developed into large irregular blotches, sometimes 5$\sim$10 mm in diameter, then coalesced. Finally, the water-soaked margins raised, dried out, became corky and broke in the center. A bacterial organism, isolated from the advancing margins of the lesions, was tested for its pathogenicity according to the Koch's postulates and biochemical and physiological tests identified the isolated bacterium as a Xanthomonas. The representative Xanthomonas strains (SL4821 and SL4822) isolated from English ivy were compared with a reference strain X. hortorum pv. hederae for fatty acid profiles, metabolic fingerprints and 16s rDNA sequences, showing that all outcomes were indistinguishable between the representative and reference strains. This is the first report of bacterial leaf spot of English ivy in Korea.

• Research in Plant Disease
• /
• v.13 no.2
• /
• pp.98-103
• /
• 2007

Grapevines will experience various types of winter damage. Some winter damages are caused by mechanical injury, freezing temperatures or poor vine vigor. This research was conducted to find out the appropriate control methods through selection of resistant rootstocks and improvement of overwintering methods for the control of crown gall disease on 'Kyoho' grape. The crown gall symptoms were not found when three stock plants of grapevine SO4, 5BB and 3306 were inoculated with $10^4cfu/ml$ of Agrobacterium vitis strains (YK2823, YK3312, LMG259, HKA234). But when they were inoculated with higher concentration $(10^6 cfu/ml)$ of A. vitis, irrespective of stocks plants, crown galls were formed all of them and the gall size was much smaller than that of kyoho. Three stock plants were selected as resistant based on above mentioned. Covering trunks and branches with rice straw and insulating coverlet was the most effective method for prevention of crown gall disease. This treatment minimized the ambient temperature changes on grapevine trees during winter season to $9.6^{\circ}C$ and the normal plant growth was due to the absence of freezing injury.

• Proceedings of the KOR-KST Conference
• /
• 1998.10a
• /
• pp.161-170
• /
• 1998

기존에 건설된 교통시설의 운영효율을 극대화하기 위한 지능형 교통체계의 한 분야인 ATIS는 도로를 이용하는 통행자에게 편리성을 제공하는 동시에 도로를 효율적으로 운영할 수 있는 정보체계이다. ATIS 체계하에서 통행자에게 신뢰성 있는 정보를 제공하기 위해서는 교차로서의 회전에 의한 지체를 정확하게 반영함은 물론이고 실시간으로 변화하는 교통상황을 반영할 수 있는 동적인 최단경로 탐색 알고리즘이 요구된다. 하지만 기존에 발표된 동적인 최단경로 탐색 알고리즘은 회전에 대한 정보를 반영하지 못하며 정적인 최단경로 탐색 알고리즘은 회전에 대한 정보를 반영하지 못하며 정적인 탐색알고리즘 조차 회전에 대한 정보를 정확히 반영하지 못한다. 본 연구에서는 이러한 이유에서 알고리즘 내부에서 회전을 반영하기 위해 수정형 덩굴망 알고리즘의 표지기법을 이용하여 동적인 최단경로 탐색알고리즘을 개발하였다. 본 연구에서 개발한 동적 최단경로 탐색 알고리즘은 정적인 상태의 수정형 덩굴망 알고리즘에 시간에 따라 변화하는 교통상황을 반영하기 위해 시간에 대한 변수를 추가하였다. 이렇게 해서 알고리즘은 시간대별로 변화하는 통행시간을 고려하여 최단 경로를 탐색하게 되며 출발시점을 기준으로 표지를 설정하여 모든 앞선 시간에 대해 경로를 고려하도록 하였다. 매 단계에서 전 노드를 추적하여 회전에 관한 정보를 반영하도록 하였다. 따라서 본 연구에서 개발한 최단경로 탐색 알고리즘은 교차로에서의 회전에 대한 정보와 통행금지 등을 정확히 반영하며 실시간으로 변화하는 통행시간을 반영함으로써 신뢰성 있는 노선 정보를 ATIS를 이용하는 통행자들에게 제공하는데 활용될 수 있는 기법이다.적으로 세부적 차종분류로 접근한다.의 영향들을 고려함으로써 가로망 설계 과정에서 가로망의 상반된 역할인 이동성과 접근성의 비교가 가능한 보다 현실적인 가로망 설계 모형을 구축하고자 한다. 지금까지 소개된 가로망 설계모형들은 용량변화에 대한 설계변수의 형태에 따라 이산적 가로망 설계 모형과 연속적 가로망 설계모형으로 나뉘어지게 된다. 본 논문의 경우, 계산속도의 향상 측면에서는 연속적 가로망 설계 모형을 도입할 수 있지만, 이때 요구되는 도로용량이 이산적인 변수(차선 수)로 결정되어야만 신호제어 변수를 결정할 수 있기 때문에, 이산적 가로망 설계 모형이 사용된다. 하지만, 이산적 설계모형의 경우 조합최적화 문제이므로 정확한 최적해를 구하기 위해서는 상당한 시간이 소요되며, 경우에 따라서는 국부 최적해에 빠지게 된다. 이러한 문제를 극복하기 위해, 우선 이상적 모형의 근사화, 혹은 조합최적화문제를 위해 개발된 Simulated Annealing기법의 적용, 연속적 모형의 변수를 이산화하는 방법 등 다양한 모형들을 고려해 본 뒤, 적절한 모형을 적용할 것이다. 가로망 설계 모형에서 신호제어를 고려하기 위해서는 주어진 가로망에 대한 통행 배정과정에서 고려되는 통행시간을 링크통행시간과 교차로 지체시간을 동시에 고려해야 하는데, 이러한 문제의 해결을 위해서 최근 활발히 논의되고 있는 교차로에서의 신호제어에 대응하는 통행배정 모형을 도입하여 고려하고자 한다. 이를 위해서 지금까지 연구되어온 Global Solution Approach와 Iterative Approach를 비교, 검토한 뒤 모형에 보다 알맞은 방법을 선택한다. 차량의 교차로 통행을 고려하는 perf

• Korean Journal of Medicinal Crop Science
• /
• v.6 no.4
• /
• pp.239-244
• /
• 1998

This experiment was to determine the effects of soil pH on crude components and aromatic constituents of Codonopsis lanceolata. Vine length of Codonopsis lanceolata grown at soil pH of 6.5 was longer(299cm) compared to that grown under other soil pHs. Fresh root weight increased at soil pH of 5.5 and 6.5, showing 17.9 and 15.6g per plant, respectively. Contents of crude components such as protein, fat, fiber, and ash decreased as soil became alkalized and crude ash content ranged from 2.99% to 3.85 %, showing a similar response to soil pH. Forty-eight volatile aromatic compounds in the root of Codonopsis lanceolata were identified by GC/MS. Major aromatic compounds were 1-hexanol, cis-3-hexanol, and trans-2-hexanol. In particular, trans-2-hexanol was highest in soil pH of 6.5, attaining the 156.87% area. Essential oil content was also highest at soil pH of 6.5 with 0.007%. As a result, it was considered that the soil pH of 6.5 was most effective for the improvement of essential oil and aromatic constituents in the roots of Condonopsis lanceolata Trautv.

• Journal of Food Hygiene and Safety
• /
• v.32 no.4
• /
• pp.306-313
• /
• 2017

This study systemically analyzed the data on the microbial levels in fresh vegetables in Korea to identify the points to control. We scanned the studies published between 2001 and 2015 in peer-reviewed research papers on the microbial levels in fresh vegetables produced in Korea. Plant products were categorized by using the US IFSAC (Interagency Food Safety Analytics Collaboration) category. The most consumed, the non-heat treated, the epidemiological foodborne diseases sources of fresh vegetable in foodservice (KCDC data) were identified by literature review. Articles were screened using National Digital Science Library (NDSL) search engine regarding to microbial hazards in plant products. Based on the total plate count number and coliforms on the 89 data cases from 26 published articles, the total plate count number was high in the order of sprouts, leaf and stem, bulbs and roots, vine-grown, solanaceous, melons, and pome. Escherichia coli was frequently detected in leaf and stem and sprouts products. Focused on the microbial data of leek, lettuce and cabbage, the levels of total plate count, coliforms and Bacillus cereus showed the levels of 4.15~7.69 log CFU/g, 1~6.99 log CFU/g, and 0.51~3.9 log CFU/g, respectively, by 33 published papers. The levels of environmental factors affecting the microbial safety of lettuce and leek before harvest were investigated. Manure, soil, hands, scale, gloves were the major potential microbial contamination points to control. In addition, GAP (good agricultural practice), microbial testing, and improvement of irrigation methods are required to provide the safer fresh produce.