• Journal of Microbiology and Biotechnology
• /
• 제13권3호
• /
• pp.415-421
• /
• 2003

A bacterium, Pseudomonas fluorescens 2112, that is antagonistic against a red-pepper blight-causing fungus, Phytophthora capsici, was isolated from the local soil of Gyongju, Korea. This strain formed an orange-colored clear halo zone on chrome azurol S (CAS) blue agar, suggesting the production of a siderophore in addition to an antifungal antibiotic. The optimal culture conditions for siderophore production by P. fluorescens 2112 were 30-h cultivation at $25^{\circ}C$ and pH 6.5 in King's B medium. The presence of $20{\mu}g/ml\;of\;Fe^3+$ ion or EDDHA promoted the production of siderophore in King's B medium. The siderophore was purified from culture broth by CM-Sephadex C-25 and Sephadex G-25 column chromatographies. The UV spectra of the purified siderophore was the same as that of pyoverdins or pseudobactins. The molecular mass was 1,958 Da determined by FAB-rlass spectrometer, and the amino acid composition analysis showed that the purified siderophore consisted of glycine/threonine/serine/glutamic acid/alanine/lysine with the molar ratio of 3:2:1:1:1:1, DL-Threo-${\beta}$-hydroxyaspartic acid and $N^{\delta}$-hydroxyornithine, two of the essential constituents of pyoverdin, were also found. The purified siderophore pyoverdin showed strong in vitro and in vivo antagonistic activities against phytophthora blight-causing P. capsici. Especially in an in vivo pot test, the siderophore protected red-pepper Capsicum annum L. very well from the attack of P. capsici. These results indicated that the purified siderophore of P. fluorescens 2112 played a critical role in the biocontrol of the red-pepper blight disease, equivalent to treatment by P.fluorescens 2112 cells.

• 한국지반공학회논문집
• /
• 제30권4호
• /
• pp.81-92
• /
• 2014

하천제방 건전도 평가는 하천설계기준 해설(2009), 구조물기초 설계기준 해설(2009) 등 관련 기준을 토대로 한계동수경사법, 한계유속법 등에 의한 파이핑 안전성과 제내지 및 제외지의 활동안전성 평가에 의하여 수행된다. 이때 수위파형은 건전도 평가 시 가장 중요한 설계입력자료이나 관련 국가기준에서 그 결정방법을 제시하지 못함으로서 부정확한 설계가 이루어지고 있다. 본 논문에서는 낙동강 문산제를 대상으로 평수위 상승, 홍수위 지속, 수위하강, 홍수빈도 등 개별 수위파형을 변화시켜가면서 제방 안정성에 미치는 영향 정도와 합리적인 수위파형특성을 제안하였다. 평가결과, 문산제 조립토 제방의 설계수위파형은 최대 57시간 이상의 평수위상승시간 및 53시간 이상의 홍수위지속시간 등을 반영할 것을 제안하였다.

• Journal of Plant Biotechnology
• /
• 제46권4호
• /
• pp.331-337
• /
• 2019

Digitaria exilis L. is an under-utilized crop with high nutritional and medicinal values. It thrives in and is well-adapted to arid areas with low soil nutrients. Using biochemical markers, this study investigates the mechanisms by which D. exilis responds to osmotic stress. Three accessions Dinat Iburua (DIN), Jakah Iburua (JAK) and Jiw Iburua (JIW) were collected from National Cereal Research Institute, Niger State. Two accessions, NG/11/JD/061 and NG/11/JD/062 were also collected from National Centre for Genetic Resources and Biotechnology, Ibadan. Murashige and Skoog medium of approximately 1.2 L was supplemented with polyethylene glycol 6000 to create osmotic pressures of -9.29, -13.93, -20.13, -26.32, -32.51, and 0 MPa (control). Sterilized seeds were inoculated in the medium and placed in the growth room for 4 weeks. Proline accumulation was significantly high in all JAK plants under osmotic stress. Proline and ascorbate peroxidase (p<0.05) activities were directly correlated, thus reinforcing the survivability of JAK during stress. Catalase (CAT) activity was also significantly induced in JAK under osmotic stress, which synergistically improved its tolerability. As a result, >50% of OH-, H₂O₂, and NO radicals were scavenged. However, other accessions including DIN, NG061, NG062, and JIW showed variations in their responses to different levels of osmotic stress, although not significant. Therefore, JAK possesses a well-equipped free radical quenching system that is protected by the accumulation of the osmolyte proline; therefore, accession JAK is considered osmotolerant. CAT and superoxide dismutase activities were osmostabilized against oxidative stress by proline.

• Journal of Forest and Environmental Science
• /
• 제29권4호
• /
• pp.249-256
• /
• 2013

The aim of the study was to reveal the scope and benefits derives from establishing carbon forests in a country like Bangladesh. Carbon forestry is the modernized forestry practice that evolves no cutting of trees or vegetation rather conserves them in the wood. Trees might be the source of carbon sink at large scale by establishing carbon forests. To find out how and in what extent forests of Bangladesh could contribute to global emission reduction, tree species of economic importance were taken into account about their carbon sequestration potential. Data source was a secondary one. Bangladesh has subtropical evergreen and deciduous forest tree species. Here trees can sequester almost 45-55 percent organic carbon in their biomass. On an average, trees in different types of stands can sequester 150-300 tC/ha. Carbon value of these forests might be 7,500-15,000 USD per hactre (assuming 50 USD per equivalent $tCO_2$). Thus, accounting tree carbon credits of total forested lands of Bangladesh, there might be a lump sum value of $1.89{\times}10^{10}-3.79{\times}10^{10}$ USD. If soil carbon is added, this amount would jump. Alternatively, there are two times higher spaces as marginal lands than this for starting carbon forestry. However, carbon forestry concept is still a theoretical conception unless otherwise their challenges are addressed and solved. Despite of this, forests of Bangladesh might be the key showcase for conserving biodiversity in association with carbon capture. Protected areas in Bangladesh are of government wealth, however, degraded and denuded waste and marginal lands might be the best fit for establishing carbon forests.

• 한국가스학회지
• /
• 제5권3호
• /
• pp.63-72
• /
• 2001

천연가스 공급용 고압 지하 매설배관에 교류가 유도될 때 쿠폰과 전기저항형 박막센서를 이용하여 교류에 의한 부식속도를 평가하고 주요한 인자를 규명하고자 하였다. 전국에 걸쳐 조사된 교류전압 측정결과를 바탕으로 쿠폰과 전기저항형 박막센서를 설치하고, 주요인자를 고찰하기 위하여 다양한 인자들 (교류전압, 교류전류, 토양 비저항, 주파수, 방식전위)을 정기적으로 기록하였다. 황산동 전극기준 -850mV의 방식전위를 충분히 만족하는 상황에서도 교류에 의한 부식이 진행하였으며, 교류에 의한 부식속도는 교류전압과는 관계없이 교류전류밀도와 주파수에 의존하는 것으로 나타났다. 교류에 의한 부식속도는 유효교류전류밀도에 따라 직선적으로 증가하였으며, 쿠폰에 의한 평가결과 직선의 기울기는 0.619, 전기저항형 센서에 의한 직선의 기울기는 0.885로 나타났다.

• 한국수자원학회논문집
• /
• 제42권7호
• /
• pp.571-578
• /
• 2009

본 연구에서는 하천의 제방붕괴시 제방의 침식 및 세굴이론에 기초한 범람 홍수량 해석, 시간에 따른 제방붕괴폭의 변화, 침수범위 및 침수위의 추정, 침수 예상 피해규모를 예측할 수 있도록 하천의 유량변화를 고려한 제방붕괴 모형을 개발코자 하였다. 하도구간에서는 홍수시 4점 음해 유한차분기법을 이용하여 하천 홍수위를 예측하며, 제방 붕괴해석을 위해서 제방침식을 고려한 토사이동방정식을 도입하여 물리적 이론에 기초한 제방붕괴 모형을 개발하였다. 제방붕괴모형과 하천해석모형을 이용하여 제방붕괴해석모형으로 통합하였고 연구모형을 실제하도 붕괴사례에 본 모형을 적용한 결과 제방붕괴 기간중의 하천수위, 파제기간, 파제폭 등의 인자들을 합리적으로 모의하고 있었고 개발된 모형이 보다 다양한 실제 하천제방 붕괴사례에 도입되어 적용성 및 정확성이 증명된다면 앞으로 정확한 제방붕괴가 발생한 도시하천의 하천수위 해석, 파제유량 계산, 홍수지도 작성 및 침수위 해석 등에 본 모형이 적용될 수 있을 것으로 판단된다.

• 한국조경학회지
• /
• 제30권5호
• /
• pp.98-106
• /
• 2002

This study was designed to present a river model with the aim of restoring the ecosystem and improving the landscape along the urban rivers on the basin of the Namhanl river, a core life channel for the National Capital regin. The revelation of botanical status, transition trend and correlation of plants might lead to providing the urban river restoration projects and ecological river formation projects with basic data for a model of ideal aquatic ecology and landscape. The outcomes of this study could be summed up as follows: 1. The plant communities of river flora found on the basin of the Namhan river could be categorized largely into 39 plant communities 2. Most diverse plants were distributed in the rivers lower reaches such as Unsim-ri where the protected zone of Paldang reservoir for city water borders the body of Jodae swamp where natural streams flow nearby. 3. One of the greatest threats to the biomass of the River Namhan is that the communities of such invasive alien plants as Panicum dichotomiflorum and Ambrosia artemisiifolia var. elatior dominate most parts of the area, a fact that has resulted in a reduced variety of plants and will, sooner or later, be likely to cause an ecological imbalance in the hitherto healthy Aquatic plant life. It is highly advisable to gradually diversify the species of trees and to return the plants bark to their original state since, besides the naturalized plants, plantations afforested with Erigeron canadensis and Erigeron annuus stocks in buckwheat field, Robinia Pseudo-accacia in riverside forest, Pinus rigida in terrestrial forest on the river basin and Larix leptolepis are anticipated to act as interceptors of normal migrations of the fluvial and terrestrial ecosystems. Finally, it seems also desirable to continue to explore the relationship between fluvial and terrestrial ecologies with the purpose of building up a model of natural streams in urban areas based on the surveyed factors for plant life, soil and landscape and, moreover, on the forecasting for overall influences derived from the rotation upon the ecosystem.

• 농촌계획
• /
• 제24권3호
• /
• pp.33-42
• /
• 2018

The aim of our study was to provide a basic data for the development of a small greenhouse model suitable for urban farmers. The study analyzed installation inclination, positive and negative reasons for installation, location of installation, preferred crops in small greenhouses, plans for use of products, and expected effects by using small greenhouse. Positive opinion on small greenhouse installation was 80.4% of the survey respondents. The most positive reason for the installation of small greenhouses was fresh and safe food supply, and the negative reason was maintenance difficulties. The results obtained in our survey indicated that small greenhouses were more likely to be installed near the house, and urban farmers tended to grow organic leafy vegetables in soil. The expected benefits of small greenhouse operation were largely divided into 'benefit for the improvement of the quality of life' and 'benefit for economic profits', and expectation for the improvement of the quality of life was higher than economic benefit. As a result of the Likert 5-point scale analysis, 'benefit for the improvement of the quality of life' by using a small greenhouse was graded as high as 4.17~4.60. On the other hand, the 'benefit to economic profits' was rated as low as 3.51~4.14.

• 한국산림과학회지
• /
• 제94권6호
• /
• pp.377-386
• /
• 2005

김해시 상동면 매리 산사태지의 발생특성을 밝히기 위한 일련의 연구를 진행중에 있으며, 본보에서는 지반조사, 시추공내영상촬영, 탄성파탐사 및 실내시험 후 안정해석을 실시하였다. 안정해석결과, 영역 I 지역은 집중호우 시 땅밀림 산사태가 발생될 위험이 있으므로 계측기를 설치하여 지표의 변위발생을 모니터링하고, 변위가 발생될 경우 긴급복구가 필요한 지역으로 판단된다. 영역 II는 토사유실이 장기간 지속될 경우 붕괴(slope failure)가 예상되므로, 향후 지속적인 관찰과 보수가 필요할 것으로 사료된다. 영역 Ill은 상부로부터 집수되는 지표수 배제 및 상부 너덜(talus)지역으로부터 침투된 지하수의 배제를 위한 시공이 필요할 것으로 사료된다. 영역 IV는 현재 안정한 지역으로 가능하면 절취 등 훼손이 발생하지 않도록 하는 것이 바람직할 것이다.

• 한국잡초학회지
• /
• 제16권3호
• /
• pp.176-180
• /
• 1996

지속적 농업을 구현하는 차원에서 제안된 논 무경운체계에서 이앙전 발생한 둑새풀을 효과적으로 방제하기 위하여 제초제의 종류와 처리시기 및 처리약량을 달리하여 둑새풀 방제가, 재생정도 및 전년도 탈립된 벼의 발생정도를 조사한 결과는 다음과 같다. 1. 둑새풀은 4월중순부터 생육이 급격히 진전되었으며, 무경운 경관년수가 깊어질수록 그 발생량은 많아졌다. 2 둑새풀 방제를 위하여 Glyphosate를 이앙전 20일경에 살포하는 것이 적당하였다. 3. 벼 이앙시 결주율은 비선택성 제초제 처리시기가 늦을수록 높아졌으며, 이앙후 생육은 처리시가가 빠를수록 양호하였다. 4. 잡벼 발생은 비선택성 제초제를 살포하지 않을 경우 1,600개체/10a 정도 발생하였으며, 제초제 처리시기가 늦을수록 적게 발생하였다.