• 한국국제농업개발학회지
• /
• 제23권5호
• /
• pp.531-536
• /
• 2011

재배토성이 감초 생육 및 품질에 미치는 영향을 구명코자 2009년부터 2년간 시험을 수행한 결과를 요약하면 다음과 같다. 1. 재배년생별 생육중 경엽은 1년생, 포복경 2년생, 근은 2년생에서 양호한 경향을 보였으며, 토성에 따라서 경엽중은 사양토에서 무거웠고, 초장, 분지수, 경태는 사질식양토에서 우수하였다. 2. 포복경의 길이, 수, 무게 등 생육은 사질식양토 > 사양토 > 양질사토 순으로 좋았다. 3. 주근과 지근의 생육은 양질사토에서 길었으며, 주근경, 지근경은 사양토에서 굵었다. 지근수는 사질식양토에서 다소 많았다. 4. 근 수량은 주근, 지근 등에서 사양토 > 사질식양토 > 양질 사토 순으로 많으며, 1년생과 2년생 근 상품 수량은 사양토에서 양질사토 204 kg/10a 대비 57%, 2년생은 71% 각각 증수하였다. 5. 글리시리진(glycyrrhizinic acid)의 함량은 1년생은 사질식 양토에서 1.62%, 2년생은 사양토에서 1.58%로 가장 높았다.

• 한국기계가공학회지
• /
• 제11권6호
• /
• pp.16-21
• /
• 2012

Magnesium alloy has been focussed as lightweight material owing to its high strength even though low density with aluminum alloy, titanium alloy and plastic material. Friction stir welding technique was performed by rotating and plunging a shouldered tool with a small diameter pin into the joint line between two butted plates and useful to join magnesium alloy. In this paper, the experiments of friction stir welding were done to investigate the joint characteristics of AZ31 magnesium alloy. For its evaluation, the orthogonal array method$(L_{27}(3^{13}))$ was applied with four factors of pin diameter, shoulder diameter, travel speed and rotation speed of tool and also three levels of each factor. Nine tools were worked through shoulder diameter of 9, 12, 15mm and pin root diameter of 3, 4, 5mm. In addition tensile tests were excuted for the assessment of mechanical properties for joint conditions. From the results, pin diameter, shoulder diameter, and rotating speed of tool influenced on the tensile strength meaningful, but welding speed did not influence on that by the variance analysis. Beside of that, optimum condition of tensile strength was estimated as following ; shoulder diameter:15mm, welding speed:200mm/min, rotating speed:200rpm.

• 한국작물학회지
• /
• 제38권3호
• /
• pp.240-244
• /
• 1993

야콘의 재배기술의 확립을 위하여 멀칭효과 및 재식밀도 실험을 한 결과는 다음과 같다. 1. 지상부 생육은 7월 중순부터 직선적으로 증가하였으며, 밀칭구나 비멀칭구에서 재식밀도가 높을수록 초장의 생육이 양호하였고, 특히 70 ${\times}$ 55cm에서 가장 좋았다. 2. 측지수는 정식 후 3개월부터 발생하였으며, 멀칭 및 재식밀도에 따라 유의한 차이를 나타내지 않았다. 3. 야콘괴경의 생체수량은 멀칭구가 비멀칭구 보다 높았으며, 멀칭구에서는 70${\times}$40cm구가 3561.7kg으로 가장 높았다. 4. 괴근수는 멀칭구에서 밀식할수록 많았으며, 근경과 근장에서는 유의적인 차이가 없었다.

• 한국생태학회:학술대회논문집
• /
• 한국생태학회 2002년도 VIII 세계생태학대회
• /
• pp.101-105
• /
• 2002

Fine root decomposition and nutrient release patterns were examined using in situ buried fine root (< 2mm in diameter) bags inserted vertically into the mineral soil to a depth of the top 15 cm in a sawtooth oak (Quercus acutissima) and a Korean pine (Pinus korainesis) stands in the Jungbu Forest Experiment Station, Kyonggi-do, Korea. The pine roots compared with the oak roots showed rapid mass loss in early stages of decomposition, but decomposed similarly after 12 months of incubation. Decomposition rates of fine roots were about 33%/yr for the oak roots and 37%/yr for the pine roots. Nutrients except for calcium and phosphorus showed similar concentrations between the oak and the pine roots during the study period. However, calcium concentration was significantly higher in the oak than in the pine roots. Nutrient concentrations in both stands except for nitrogen decreased during the study period. In addition, potassium compared with other nutrients was the most mobile ion and about 70% of initial amount was released during the first 3 months of incubation. The results indicate that tree species influence mass loss and nutrient dynamics of fine roots on similar site conditions.

• 한국작물학회지
• /
• 제32권4호
• /
• pp.425-430
• /
• 1987

남부지방에서 황금의 직파재배와 육묘이직 재배시 적정 파종기와 정식기를 구명하고자 시험을 실시한 결과는 다음과 같다. 1. 출현은 황금의 파종기나 정식기가 빠를수록 늦어지고 늦어질수록 단축되는 경향으로 출현일수와 파종기 및 정식기간에는 고도의 부의 상관이 인정되었다. 2. 생육은 직파재배에 있어서 4월 15 일의 파종이 초장과 경태가 크고 분지수가 많아서 가장 양호하였으며, 육묘이식재배는 4월 1일 정식이 가장 좋은 경향이었다. 3 수량은 직파담배에서는 4월 15일 파종, 육묘 이식재배는 4월 1일 정식에서 근장이 가장 크고, 건근중이 무거워 수량이 증수되었다. 4 주요 형질간 상관을 보면 수량은 초장과 분지수, 그리고 근장과 정의 상관 관계를 나타내었고, 근장은 건근중과 건경중에 고도의 정의 상관 관계가 인정되었다.

• The Korean Journal of Ecology
• /
• 제25권4호
• /
• pp.235-239
• /
• 2002

Fine root decomposition and nutrient release patterns were examined using in situ buried fine root (＜ 2mm in diameter) bags inserted vertically into the mineral soil to a depth of the top 15 cm in a sawtooth oak (Quercus acutissima) and a Korean pine (Pinus korainesis) stands in the Jungbu Forest Experiment Station, Kyonggi-do, Korea. The pine roots compared with the oak roots showed rapid mass loss in early stages of decomposition, but decomposed similarly after 12 months of incubation. Decomposition rates of fine roots were about 33%/yr for the oak roots and 37$\%$/yr for the pine roots. Nutrients except for calcium and phosphorus showed similar concentrations between the oak and the pine roots during the study period. However, calcium concentration was significantly higher in the oak than in the pine roots. Nutrient concentrations in both stands except for nitrogen decreased during the study period. In addition, potassium compared with other nutrients was the most mobile ion and about 70$\%$ of initial amount was released during the first 3 months of incubation. The results indicate that tree species influence mass loss and nutrient dynamics of fine roots on similar site conditions.

• 한국균학회지
• /
• 제48권4호
• /
• pp.499-503
• /
• 2020

Clubroot symptoms were frequently observed on the roots of Baecheongchae plants grown in vinyl greenhouses of a farmer located in Yangpyeong area of Korea during a disease survey in June 2019. The incidence of diseased Baecheongchae plants ranged from 30 to 90% in the vinyl greenhouses investigated. Many resting spores were found in the tissue of root galls collected. The resting spores were hyaline and spherical and measured 2.5-4.2 ㎛ in diameter. Three inoculum suspensions of resting spores prepared from the root galls were inoculated to the roots of healthy Baecheongchae plants. All the inoculum suspensions caused clubroot symptoms to appear on the roots of the inoculated Baecheongchae plants. The symptoms on the roots induced by artificial inoculation were similar to those observed in the plants of the vinyl greenhouses during the disease survey. Resting spores of the pathogen were recovered from the root galls of the inoculated plants. Three root gall isolates obtained from the inoculated plants were used for molecular identification. Comparing the isolates to the Plasmodiophora brassicae strains in GenBank, the amplification products demonstrated 100% similarity with the internal transcribed spacer (ITS2) sequences. The clubroot pathogen was identified as P. brassicae according to its morphological, pathological, and molecular characteristics. This is the first report of P. brassicae causing clubroot in Baecheongchae.

• Journal of Microbiology and Biotechnology
• /
• 제29권11호
• /
• pp.1777-1789
• /
• 2019

Drought is more concerned to be a huge problem for agriculture as it affects plant growth and yield. Endophytic bacteria act as plant growth promoting bacteria that have roles for improving plant growth under stress conditions. The properties of four strains of endophytic bacteria were determined under water deficit medium with 20% polyethylene glycol. Bacillus aquimaris strain 3.13 showed high 1-aminocyclopropane-1-carboxylate (ACC) deaminase production; Micrococcus luteus strain 4.43 produced indole acetic acid (IAA). Exopolysaccharide production was high in Bacillus methylotrophicus strain 5.18 while Bacillus sp. strain 5.2 did not show major properties for drought response. Inoculation of endophytic bacteria into plants, strain 3.13 and 4.43 increased height, shoot and root weight, root length, root diameter, root volume, root area and root surface of Jerusalem artichoke grown under water limitation, clearly shown in water supply at 1/3 of available water. These increases were caused by bacteria ACC deaminase and IAA production; moreover, strain 4.43 boosted leaf area and chlorophyll levels, leading to increased photosynthesis under drought at 60 days of planting. The harvest index was high in the treatment with strain 4.43 and 3.13 under 1/3 of available water, promoting tuber numbers and tuber weight. Inulin content was unchanged in the control between well-watered and drought conditions. In comparison, inulin levels were higher in the endophytic bacteria treatment under both conditions, although yields dipped under drought. Thus, the endophytic bacteria promoted in plant growth and yield under drought; they had outstanding function in the enhancement of inulin content under well-watered condition.

• Journal of Ginseng Research
• /
• 제3권2호
• /
• pp.105-112
• /
• 1979

Effect of gibberllin on the breaking of bud dormancy of root and growth of aerial parts were investigated under laboratory and field condition for the prolongation of shoot growth duration, shortening of fruit bearing age and the increase of root yield. Drop application of GA (0.5ml of 50ppm) on rhizome of one year old root broke bud dormancy better than by low temperature. Soaking for one hour of one year old roots which wintered in the field in GA (50-200ppm) greatly accelerated the emergence of new buds while kinetin was only effective at low level (50ppm). GA substantially increased stem length in early stage and petiole length later on while kinetin increased stem diameter. Under the field condition with polythylene film tunnel (PET) in early spring the soaking in GA (50ppm for 1 hour) of rhizome of 4 year old root with replanting and dropping GA (50ppm, 1ml) on rhizome without replanting brought earlier emergence (29days) in comparison with that in the usual field. PET alone caused 14 day-early emergence. GA increased the length of stem and petiole only in early stage and replanting decreased only petiole length in later stage. Soaking in GA with replanting caused the Pronounced decrease in peduncle length, percentage of (ruin set and dry weight of reproductive organ (fruits and peduncle). Dropping without replanting showed significant decrease only in dry weight of reproductive organ. Fruit maturing was 20 days earlier than in usual held with little difference between GA and PET. It is well expected that GA could be used for early emergence of bud, shortening of root dormancy period, thinning of fruit and higher root yield according to application amount and methods.

• 한국작물학회지
• /
• 제39권5호
• /
• pp.426-430
• /
• 1994

참당귀 본포 이식시 묘의 중양에 따른 생육상황과 추대정도를 조사하고 추대에 대한 지상하부 형질간의 상관관계를 조사한 결과를 요약하면 다음과 같다. 1. 묘의 중양이 클수록 왕성한 생육을 보여 초장, 화서수, 추대율에서 유의성을 나타내었고 현재의 일반 관행묘보다 더 작은 소묘를 이식하므로서 16% 정도의 추대율 감소효과를 기대할 수 있었다. 2. 수양면에서는 이식 당귀묘의 중량이 클수록 추대율이 높아져 뿌리가 목질화되고 왜소하게 되어 근중이 적어지므로서 수량이 감소하는 경향을 보여 가급적 5g미만의 소묘가 좋을 것으로 사료되었다. 3. 지상하부 형질간의 상관관계를 보면 지상부형질간, 또는 지하부형질간에는 정의 상관을 보였으나 지상하부 형질간에는 부의 상관을 나타내었다. 4. 추대율과 높은 상관관계를 갖는 형질은 초장, 엽수, 화서수 및 생체중 등이혀 추대에 의해 가장 영향을 받는 근형질은 근중이었다.