• Korean Journal of Weed Science
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• v.13 no.2
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• pp.89-95
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• 1993

The Inhibiting activity of newly synthesized phenol (E-series) and triazine (T-series) derivatives was evaluated by using thylakoid membranes extracted from cyanobacteria (Anacystis nidulans $R_2$). There were no significant differences between phenol derivatives and dinoseb to the thylakoid membrane extracted from wild type in the Hill reaction. However, a phenol derivative, E-24 which has no -Cl at phenyl ring, did not show any activity. The longer the length of R substituents was in phenol derivatives, the lower inhibiting activity was in the Hill reaction. Triazine derivatives, T-27, T-28, T-40, T-41, T-47 and T-48 were also compared with diuron and atrazine. Among triazine compounds, T-27 and T-28 showed 10 and 30 times activity as high as atrazine to wild type, respectively. Other triazine derivatives, T-40, T-41, T-47 and T-48 showed low inhibiting activity to wild and mutant type. A structural difference of T-27 and T-28 from T-40, T-41, T-47 and T-48 was the presented of -C-NH-. Both T-27 and T-28 were very closely associated with serine, an amino acid located at the 264th position of D1 protein because of the resistant ratio(R/S) to mutant G-264 were higher than that of atrazine.

• Korean Journal of Environment and Ecology
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• v.18 no.2
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• pp.191-196
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• 2004

Mt. Deogyusan, 1,614m in altitude, is located in the southwest of South Korea. Around Mt. Duckyu, many Korean endemic and rare plants are populated, so it is considered a very important biogeographical area where the temperature zones of northern and southern plants are crossed. Because it is the graceful figure of Mt. Duckyu, it is a common mountain where many tourists visit frequently. Continuous tourist's visit may cause a bad influence on vegetation around the climbing paths. Therefore, weed community around the climbing paths on Mt. Duckyu, where visitors exert a bad influence directly on its community by coming in and out, was surveyed phytosocialogically. Our surveys have been accomplished from July to August, 2003. Weed communities formed around the climbing paths on Mt. Duckyu were divided into several patterns and analysed. They have been divided into 8 communities and 4 subcommunities. Community A: Plantago asiatica community, A-a: Carex bostrychostigma subcommunity, A-b: Artemisia princeps var. orientalis subcommunity, B: Sasa borealis community, B-a: Carex siderosticta subcommunity, B-b: Veratrum parulum subcommunity, C: Rubus crataegifolius community, D: Hosta longipes community, E: Tripterygium regelii community, F: Miscanthus sinensis var. purpurascens community, G: Carex okamotoi community, H: Lespedeza maximowiczii community. The flora surveyed in these communities was constituted of 34 families, 83 genera, 12 varieties, and 92 species. Wild plants such as Plantago asiatica, Artemisia princeps var. orientalis, Rubus crataegifolius, Sasa borealis and Miscanthus sinensis var. purpurascens were mostly light loving plants and higher resistant plants against the stamping pressure.

• Weed & Turfgrass Science
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• v.3 no.3
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• pp.165-173
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• 2014

This review study was conducted to recommend the effective use of herbicide mixtures in Korea. The herbicide ingredients by Herbicide Resistancce Action Committee (HRAC) was classified into 23 groupes according to the mode of action (acetyl CoA carboxylase inhibitors, acetolactate synthase, photosystem I and II inhibitors, protoporphyrinogen oxidase inhibitors, carotenoid biosynthesis inhibitors, enolpyruvyl shikimate-3-phosphate synthase inhibitors, glutamine synthetase inhibitors, dihydropteroate synthetase inhibitors, mitosis inhibitors, cellulose inhibitors, oxidative phosphorylation uncouplers, fatty acid and lipid biosynthesis inhibitors, synthetic auxins, auxin transport inhibitors and potential nucleic acid inhibitors or non-descript mode of action). The rice herbicide mixtures registered in Korea were classified based on the guideline of HRAC. Accordingly, such a classification system for resistance management can help to avoid continuous use of the herbicide having the same mode of action in the same field.

• Journal of Plant Biotechnology
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• v.38 no.4
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• pp.272-277
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• 2011

Plants expressing Agrobacterium sp. strain CP4 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) are known to be resistant to glyphosate, a potent herbicide that inhibits the activity of the endogenous plant EPSPS. In order to develop herbicide-resistant rice, we prepared transgenic rice plants with CP4 EPSPS gene under the control of CaMV 35S promoter for over-expression. A recombinant plasmid was transformed into rice via Agrobacterium-mediated transformation. A large number of transgenic rice plants were obtained with glyphosate and most of the transformants showed fertile. The integration and expression of CP4 EPSPS gene from regenerated plants was analyzed by Southern and northern blot analysis. The transgenic rice plants had CP4 EPSPS enzyme activity levels more than 15-fold higher than the wild-type plants. EPSPS enzyme activity of transgenic rice plants was also identified by strip-test method. Field trial of transgenic rice plants further confirmed that they can be selectively survived at 100% by spay of glyphosate (Roundup$^{(R)}$) at a regular dose used for conventional rice weed control.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.121-126
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• 2012

National Academy of Agricultural Science and eight province Agricultural Research & Extension Services investigated the occurring area of herbicide resistant weeds in paddy field of Korea. In order to estimate the occurring areas of herbicide resistant weeds, we collected paddy soils on August, 2011 and treated 30kg $ha^{-1}$ of pyrazosulfuron-ethyl+pyriminobac-methyl GR. 167,081ha, approximately 20.9% of cultivated area excluding organic and eco-friendly cultivated area, was estimated to be infested by SU-herbicide resistant paddy field weeds. It was increased by 60,130ha compared with investigation of 2008. It was occurred at Chungchungnam-do by 47.6%, followed by 36.9% at Jeonranam-do, 25.7% at Chungchungbuk-do, 20.5% at Gangwon do, and 13.0% at Gyeonggi-do, respectively. Monochoria vaginalis showed the highest with 65,313ha, 39.1% followed by Scirpus juncoides, and Cyperus difformis, respectively. These three species were evenly distributed and the most problematic weeds in the country. Lindernia dubia occurred at 13,964ha (8.4%) and Echinochloa oryzicola was 5.1%, respectively.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.380-389
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• 2010

Transgenic herbicide-resistant sweet potato plants [Ipomoea batatas (L.) Lam.] produced through a biolistic transformation were used in this study. The objective of this research was to find out a rapid and reliable assay method for confirming glufosinate-ammonium resistance. The techniques tested include whole-plant bioassay, one leaf bioassay, and leaf disk bioassay. Parameters investigated in this study were leaf injury and ammonium accumulation at 1 and 5 days after treatment of glufosinate-ammonium. In the leaf disk bioassay, leaf injury of the transgenic line 7171 was 1.9-fold less affected by glufosinate-ammonium than the wild type. The leaf injury of 7171 in one leaf and whole-plant bioassays was 59- and 92-fold less affected by glufosinate-ammonium, respectively, compared with that of the wild type. Leaf disk, one leaf, and whole-plant bioassays showed that ammonium accumulation of the 7171 was 2 to 20-, 4 to 43-, and 6 to 115-fold less affected by 0.5-5 mM glufosinate-ammonium than that of the wild type. All three bioassays successfully distinguished the resistance from the transgenic lines, but one leaf bioassay is the simplest and quickest. Leaf injury and ammonium accumulation were the same in leaves 1, 3, 5, 7, and 10 of 3 mM glufosinate-ammonium treated plants or nontreated plants. The one leaf bioassay was chosen as the standard procedure for future confirmation of resistance in transgenic sweet potato because it is a rapid and reliable assay.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.285-293
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• 1990

The response of callus growth of rice (Oryza sativa L.) cultivars which showed different responses to herbicides as seedlings was investigated to select resistant or tolerant calli. Callus growth of IR28 which was susceptible to thiobencarb (S-[(4-chlorophenyl)methyl]diethylcarbamothioate) during callus induction was not inhibited by $10^{-5}$ M and $10^{-6}$ M thiobencarb, indicating that there was a difference in tolerance among callus induction and growth, and the intact plant level. A similar result was obtained with IR31917-45-3-2-2 to butachlor [N - (buthoxymethyl) -2-chloro-N- (2, 6-diethylphenyl) acetamide]. The fresh weight of IR28 callus transferred into $10^{-5}$ M thiobencarb after treatment at $10^{-6}$ M for 30 days was not affected by the herbicide, indicating that transferring callus into gradually higher herbicide concentrations can be a useful method for selection of herbicide-tolerant cell lines.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.81-88
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• 1993

For searching the photosynthetic electron transport(PET) inhibitors, bio-rational screening system using thylakoid membranes extracted from wild and mutant cyanobacteria(Anacystis nidulans $R_2$) was developed. Generally, thylakoid membrane was more sensitive to the tested herbicides than the chloroplast from spinach in the Hill reaction. Higher resistant characteristics appeared in mutant D-5, Di-22 to diuron and mutant G-264 to atrazine as compared to wild type. To test the reaction of thylakoid membrane to herbicides, diuron and atrazine were applied simultaneously. Diuron and atrazine competed each other for binding with substituted amino acids, while diuron and dinoseb were non-competitive, and inhibiting activity was increased. Conclusively, bio-rational screening system using cyanobacteria was proved to be fast and efficient screening method for the development of PET inhibitors.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.136-150
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• 2017

Zoysiagrass mite, Aceria zoysiae is one of the main turfgrass pests causing significant damage on zoysiagrass. In this study we investigated damage by zoysiagrass mite for the selection of zoysiagrass mite-resistance turfgrass individual in natural collected turfgrass isolates transplanted in genetic resources conservation area. In the results of investigation of 295 turfgrass isolates collected from Korea, damage level was different depending on turfgrass species and individuals. Zoysia japonica was highly damaged representing 97.6%, followed by hybrid zoysia and Z. sinica with damage percentages of 87.7% and 81.1% respectively. Additionally, 2 individuals of Z. macrostachya were also damaged by zoysiagrass mite. However several individuals were not damaged by zoysiagrass mite in green house and field. Damage by zoysiagrass mite was occurred from May and peak at after July in field. The study highlighted some important resistant turfgrass individuals which can be used in the management of zoysiagrass mite.

• Korean Journal of Weed Science
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• v.18 no.3
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• pp.237-245
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• 1998

The transgenic tobacco (Nicotiana tabacum cv. Xanthi) plants containing Bacillus subtilis protoporphyrinogen oxidase gene with cauliflower mosaic virus 35S promoter have recently been generated by using Agrobacterium-mediated gene transformation. The nontransgenic and the transgenic tobacco plants were compared with respect to responses to diphenyl ether herbicide oxyfluorfen and under various environmental conditions. Both cellular leakage and lipid peroxidation caused by oxyfluorfen were found to be less in the transgenic than in the nontransgenic plants. Growth responses of the transgenic plants under various temperature, light, and water conditions were almost the same as those of the nontransgenic plants, although the transgenic plants exhibited slightly more retarded growth under low light or saturated water condition. These results revealed that the transgenic tobacco plants containing B. subtilis protoporphyrinogen oxidase gene under cauliflower mosaic virus 35S promoter were relatively resistant to oxyfluorfen and exhibited normal growth pattern. Possible mechanism of resistance to oxyfluorfen in the transgenic plants is also discussed.