• 농업과학연구
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• 제39권4호
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• pp.473-476
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• 2012

The experiment was conducted to investigate the herbicidal efficacy of imazosulfuron mefenacet by using remote-controlled aerial application (RCAA) to control annual and perennial weeds in rice paddy field. Eight annual weed species including Echinochloa crus-galli L. and three perennial weeds were dominated in the experimental field. Application of imazosulfuron mefenacet using RCAA was highly effective to control both annual and perennial weed species. No phytotoxic effect was observed in the rice based on the plant height and the number of tillers. Finally, rice yield in the imazosulfuron mefenacet treatment was as much as that in the hand weeding. This study indicates that imazosulfuron mefenacet using RCAA can be applied to control both annual and perennial weed species in rice paddy field.

• 한국작물학회지
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• 제51권1호
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• pp.101-106
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• 2006

Common thistle contains water-soluble substances that are phytotoxic to neighboring plant species. A series of aqueous extracts from leaves, stems, roots and flowers of common thistle (Cirsium pendulum Fisch.) were assayed against alfalfa (Medicago sativa) seedlings to determine their allelopathy, and the results showed highest inhibition in the extracts from flowers and leaves, and followed by stems, and roots. The extracts at 40 g dry tissue $L^{-1}(g\;L^{-1})$ applied on filter paper in a Petri-dish significantly inhibited root growth of test plant by 87%. Methanol extracts at 100 g $L^{-1}$ from leaves inhibited root growth of alfalfa and barnyardgrass (Echinochloa crus-galli) by 89 and 98%, respectively. Hexane and ethylacetate fractions of common thistle reduced alfalfa root growth more than did butanol and water fractions. Incorporation into soil with the leaf residues at $100g\;kg^{-1}$ inhibited shoot fresh weights of barnyardgrass and eclipta (Eclipta prostrate) by 88 and 58%, respectively, showing higher sensitivity in grass species. These results suggest that common thistle plants had allelopathic potential for eco-friendly vegetation management, and that especially their activities were differently exhibited depending on plant part.

• Asian Journal of Atmospheric Environment
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• 제5권4호
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• pp.205-215
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• 2011

Ozone ($O_3$) is a main component of photochemical oxidants and a phytotoxic air pollutant. Although the current levels of tropospheric $O_3$ in East Asia could adversely affect productivity of forest tree species, risk assessments of $O_3$ impact were limited. In this paper, we summarize the methodology of risk assessment of $O_3$ on forest tree species based on our two previous studies, risk assessments of $O_3$ impact on the growth of Fagus crenata by Watanabe et al. (2012) and on the annual carbon absorption of three representative conifers, Cryptomeria japonica, Pinus densiflora and Larix kaempferi by Watanabe et al. (2010). $O_3$ sensitivity of each tree species obtained from an experimental study, $O_3$ exposure and atmospheric N deposition based on field monitoring and vegetation survey were integrated by geographic information system method. Based on the results, we conclude that the area with high risk of $O_3$ impact does not necessarily correspond to the area with high $O_3$ exposure. The varieties of tree habitat, tree sensitivity to $O_3$ and annual carbon absorption among the tree species, and N deposition-induced change in the $O_3$ sensitivity of F. crenata are raised as the factors of discordance between areas with high risk and those with high $O_3$ exposure. In the last part of this paper, we discuss the present uncertainty and perspectives of risk assessment for the future studies on the impact of $O_3$ on forest tree species in East Asia.

• 농업과학연구
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• 제38권2호
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• pp.191-198
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• 2011

Herbicidal effects and crop selectivity of aqueous leaf extracts of sorghum (Sorghum bicolor L.) were evaluated against several weed species for developing sustainable weed management in organic farming. Aqueous sorghum leaf extracts were highly phytotoxic to different weed species. No broadleaf weeds were germinated in the concentration of 5 fold or higher concentrated sorghum leaf extracts and 90% of seed germination was inhibited within that range in grass species. Sorghum leaf extracts strongly inhibited the growth of different weeds by pre-emergence and foliar applications in greenhouse condition. Foliar application of sorghum leaf extracts had a higher inhibitory effect than the pre-emergence application. Broadleaf weed species were more susceptible than grasses to the application of sorghum leaf extract in foliar applications than grasses. Galium spurium, Erigeron candensis, and Rumex japonicus were completely killed at the highest concentrated sorghum leaf extract both in pre-emergence and foliar application. Most broadleaf weed species were inhibited more than 80% at pre-emergence application at 50 fold concentrated sorghum leaf extract. G. spurium, E. candensis, R. japonicus, Eclipta alba, Plantago asiatica and Portulaca oleraeea were most susceptible to sorghum leaf extract in foliar application. Growth of most broad leaf weed species was suppressed by greater than 90% at 50 fold concentrated sorghum leaf extract. Most crop species were tolerant to sorghum leaf extract but shoot growth was slightly reduced by the application of 40~50 fold concentrated extracts, Sorghum leaf extract may used to control weeds in organic fanning without affecting the growth of crop.

• 농업과학연구
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• 제43권4호
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• pp.522-536
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• 2016

Fluorine is unique chemical element which occurs naturally, but is not an essential nutrient for plants. Fluoride toxicity can arise due to excessive fluoride intake from a variety of natural or manmade sources. Fluoride is phytotoxic to most plants. Plants which are sensitive for fluorine exposure even low concentrations of fluorine can cause leave damage and a decline in growth. All vegetation contains some fluoride absorbed from soil and water. The highest levels of F in field-grown vegetables are found up to $40mg\;kg^{-1}$ fresh weight although fluoride is relatively immobile and is not easily leached in soil because most of the fluoride was not readily soluble or exchangeable. Also, high concentrations of fluoride primarily associated with the soil colloid or clay fraction can increase fluoride levels in soil solution, increasing uptake via the plant root. In soils more than 90 percent of the natural fluoride ranging from 20 to $1,000{\mu}g\;g^{-1}$ is insoluble, or tightly bound to soil particles. The excess accumulation of fluorides in vegetation leads to visible leaf injury, damage to fruits, changes in the yield. The amount of fluoride taken up by plants depending on the type of plant, the nature of the soil, and the amount and form of fluoride in the soil should be controlled. Conclusively, fluoride is possible and long-term pollution effects on plant growth through accumulation of the fluoride retained in the soil.

• Applied Biological Chemistry
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• 제50권4호
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• pp.316-320
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• 2007

Chaetomium sp.배양체를 acetone에 침지하여 추출한 후 n-hexane, $CHCl_3$, EtOAc, n-BuOH 및 물로 분획하였다. 이중 EtOAc 분획을 silica gel 및 HPLC(ODS)를 이용하여 3종의 활성물질 A.C-3, A.C-4 및 A.C-5를 분리하였다. 각 화합물의 화학구조를 NMR 및 MS등의 스펙트럼 데이터와 문헌검색을 통하여 chaetoglobosin 유도체인 chaetoglobosin F, chaetoglobosin C 및 chaetoglobosin E로 동정하였다. A.C-3, A.C-4 및 A.C-5의 논피에 대한 유근신장 저해활성 검정 결과, $IC_{50}$값은 각각 66, 65, $67{\mu}g/ml$이었다.

• 한국지반환경공학회 논문집
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• 제3권4호
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• pp.5-10
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• 2002

Pistia stratiotes(Water Lettuce)는 고도처리를 위한 폐수로부터 무기오염원 제거에 적용되어질 수 있다. 본 연구는 2차 처리된 폐수로부터 중금속을 제거하기 위하여 시도하였다. 납(Pb)과 크롬(Cr(VI))의 초기 농도를 0.5, 1.0, 1.5mg/L로 각각 다르게 적용되어 졌다. 그 외에 납(Pb)과 크롬(Cr(VI))을 혼합하여 제거효율을 관찰하였다. Pistia stratiotes에 의해 납(Pb)은 41.0~72.0%의 제거효율을 보였고 크롬(Cr(VI))은 25.0~30.0%의 제거효율을 보였다. Pistia stratiotes는 정지된 상태에서 수일 동안 중금속에 노출되어 중금속을 제거할 수 있었다. 그러나, 중금속은 식물에 독성을 일으켜 엽록소합성을 억제하고 생체량이 감소하면서 결국은 식물의 일부가 사멸하는 것이 관찰되었다. Pistia stratiotes에 의한 납(Pb)과 크롬(Cr(VI))의 제거효율은 식물의 성장과 함께 증가하였다.

• Asian Journal of Atmospheric Environment
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• 제5권2호
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• pp.65-78
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• 2011

Ozone ($O_3$) is a main component of photochemical oxidants, and a phytotoxic anthropogenic air pollutant. In North America and Europe, the current concentration of $O_3$ has been shown to have significant adverse effects on vegetation. In this review, we summarize the experimental studies on the effects of $O_3$ on the growth and photosynthetic activity of Japanese forest tree species to understand the present knowledge and provide sound basis for future research toward the assessment of $O_3$ impacts on Japanese forest ecosystem. Since the 1990s, several Japanese researchers have conducted the experimental studies on the effects of ambient levels of $O_3$ on growth and physiological functions such as net photosynthesis of Japanese forest tree species. Although the sensitivity to $O_3$ of whole-plant growth is quite different among the species, it was suggested that the current ambient levels of $O_3$ in Japan are high enough to adversely affect growth and photosynthetic activity of Japanese forest tree species classified into high $O_3$ sensitivity group such as Japanese beech. The N load to soil has been shown to reduce the sensitivity to $O_3$ of Japanese larch and increase that of Japanese beech. To establish the critical level of $O_3$ for protecting Japanese forest tree species, therefore, it is necessary to take into account the N deposition from the atmosphere. There is little information on the combined effects of $O_3$ and other environmental factors such as elevated $CO_2$ and drought on growth and physiological functions of Japanese forest tree species. Therefore, it is necessary to promote the experimental study and accumulate the information on the combined effects of $O_3$ and any other abiotic environmental factors on Japanese forest tree species.

• 농약과학회지
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• 제12권4호
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• pp.403-413
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• 2008

벼의 주요 병해충인 도열병, 잎집무늬마름병, 벼멸구 및 나방류를 동시에 방제할 수 있는 항공방제용 고농도 소량살포 가능 농약혼용조합 209조합에 대하여 시험한 결과, 벼는 물론 주변작물에 약해가 없고 살포액의 물리성이 양호한 tricyclazole SC + validamycin-A SL + imidacloprid SL 등 우수 혼용조합 93 조합을 최종 선발하였다. 선발된 조합의 항공살포에 의한 약효는 일반살포의 방제효과와 비슷하였다. 또한 유인헬기에 의한 항공방제는 일반 관행살포에 비해 방제비용을 1/4 수준으로 크게 줄일 수 있음을 확인하였다.

• Journal of Applied Biological Chemistry
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• 제52권4호
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• pp.195-199
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• 2009

현재 산업적으로 여러 가지 용도로 사용되고 있는 계면활성제 중에서 임의로 선택한 비이온성 계면활성제와 음이온성 계면활성제 수용액을 온실 내에서 자연적으로 흰가루병 발생을 유도한 성체 오이에 분무 살포한 후 병 방제효과를 측정함으로써 약해 유발이 없으면서 병 방제 효과가 우수한 계면활성제를 선발하였다. 이 계면활성제 수용액을 DBEDC 희석액과 혼합처리하여 흰가루병에 대한 방제력의 변화를 조사함으로써 합제개발의 가능성을 시험하였다. 시험한 20종의 계면활성제 중에서 pentaetylene glycol monododecyl ether, pentaethylene glycol monodecyl ether와 pentaethylene monododecyl ether의 혼합물 및 pentaethylene glycol mono-9-octadecenyl ether 등이 약해를 거의 유발하지 않으면서 흰가루병에 대한 높은 방제 효과를 보였는데, 그 효과는 fenarimol 유제보다 우수하거나 대등한 것으로 나타났다. 이중 pentaethylene glycol monododecyl ether는 예방효과가 우수한 DBEDC와 혼합처리 하였을 때 서로 상가적으로 작용하여 현저하게 높은 방제 효과를 나타내었다.