• Research in Plant Disease
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• v.15 no.2
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• pp.112-119
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• 2009

We discovered two novel phytotoxins produced by the pathogenic fungus, Botrytis cinerea. Among the twenty-five B. cinerea isolates, which were obtained from various host plants in 1994 and 1996, twenty-two showed strong or moderate pathogenicity on five plants such as cucumber, tomato, red pepper, tobacco and Chinese cabbage. The culture filtrate of the B. cinerea 2-16 strain showed the most potent phytotoxic activity in a tobacco leaf-wounding assay. Two novel phytotoxins were isolated from the liquid cultures of B. cinerea 2-16 by ethyl acetate extraction, flash silica gel column chromatography, silica gel column chromatography, Sephadex LH-20 column chromatography, preparative TLC and subsequently preparative HPLC. Their chemical structures were determined to be 3-O-acetyl botcinol and 3-O-acetyl botcinolide, respectively, by mass and NMR spectral analyses. These two phytotoxins caused leaf necrosis in a leaf-wounding bioassay, and significant electrolyte leakage from leaf tissues of tobacco. In the two bioassays tested, 3-O-acetyl botcinol exhibited stronger phytotoxic activity than 3-O-acetyl botcinolide. This is the first report on the production of both 3-O-acetyl botcinol and 3-O-acetyl botcinolide from B. cinerea.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.209-218
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• 2015

This study was conducted to investigate the weed occurrence and distribution on the upland crop fields (garlic, barley, potato, maize, red pepper, soybean and Chinese cabbage) at 795 sites in Chungbuk province of Korea from Apr. to Oct. in 2014. From the result of this survey, 188 weed species in 42 families were identified and classified to 96 annuals, 40 biennials and 52 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province upland crop fields were higher in the order of Portulaca oleracea (8.14%), Digitaria ciliaris (6.72%), Echinochloa crus-galli (6.55%), Rorippa palustris (6.00%) and Chenopodium album (5.89%). The composition of major occurred weed families, Compositae, Poaceae, Polygonaceae and Cruciferae were 19, 10, 7 and 6%, respectively. In the winter upland crop fields, the dominant weeds were in the order of Capsella bursa-pastoris (12.36%), Alopecurus aequalis (11.05%) and Stellaria alsine (8.42%). In the summer upland crop fields, the dominant weeds were in the order of Portulaca oleracea (8.58%), Digitaria ciliaris (7.18%) and Rorippa palustris (6.28%). Fiftythree exotic weed species were identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the upland crop fields in Chungbuk province of Korea.

• Korean Journal of Medicinal Crop Science
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• v.6 no.4
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• pp.277-285
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• 1998

Antifungal activity on major seedborne diasease of crops was screened by the treatment of the extracts from 50 medicinal plants in vitro and in vivo. The extracts of garlic and taxus, Rheum undulatum, Achiranthes japonica, Glycyrrhiza uralensis, Oenothera lamar kiana treated with the blotting filter paper and water agar methods inhibited the growth of Pyricularia oryzae, Alternaria sesamicola, Colletotrichum gloeosporioides, and Alternaria brassicicola among the tested plants. Antifungal activities on infected seeds by soaking methods were shown even at the dilution of the extracts by 10 times. The activity was the highest in soaking seeds at $25^{\circ}C$ for 24 hours. The effect of plant extract on seed germination was not significant as compared with untreated seed. However, early growth of seedling was increased by the treatment of extracts. The extract of taxus slightly inhibited the seed germination of radish and chinese cabbage but those of Achirunthes japonica, Glycyrrhiza uralensis and Oenthfera lamarkiana showed severe damage on the seed germination and early growth of seedling.

• Korean Journal of Environmental Agriculture
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• v.33 no.1
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• pp.17-23
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• 2014

BACKGROUND: Crop rotation is often used as a solution to eradicate nematodes in soils used in plastic film houses for long-term cultivation of oriental melon. However, it is not clear if the double-cropping is effective in reducing nematode populations in soils. METHODS AND RESULTS: Nematode population in plastic film house soil was measured during oriental melon cultivation from April to July in short term crop rotation systems of oriental melon. Double-cropping of chinese cabbage in open-field for 3-4 months following oriental melon in plastic film houses could not prevent the build-up of high population density of nematodes. However, double-cropping of dropwort in flooded soil for 3-4 months following oriental melon in plastic film houses could effectively reduce the nematode population during the successive year of oriental melon cultivation. The reduced nematode population in soils of oriental melon-dropwort double-cropping system was continued until the mid season of progressive year oriental melon cultivation. Application of nematicide to soil before growing oriental melon in the oriental melon-dropwort double-cropping was very effective in preventing the build-up of high population density of nematode in plastic film house soils. CONCLUSION: Short-term introduction of crop rotation was not effective in suppression of high population density of nematodes in plastic film house soils of long-term year-to-year production of oriental melon. For securing the soil productivity and sustainability of plastic film house, various physical, chemical, and agronomic practices should be properly combined together.

• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.123-134
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• 1992

In order to verify the usability of the greenhouse for aquaculture with nutrient culture synchronously and to obtain the fundamental data fir the establishment of efficient farming technology, the characteristics of microclimate and the growth of leafy vegetables were examined. Tilapia averaged 428.6 g grew to 784 g(1.83 times) for 147 days from May 29 to Oct. 21 and fingerlings averaged 12.9 g grew by 1.37 times for 61 days from Sep. 13 to Nov. 12. The growth of vegetables such as water dropwort, leaf lettuce, Chinese cabbage, and Welsh onion in the greenhouse was better for aquaculture with nutrient culture than for nutrient culture only. Between above two greenhouses, pH and EC of nutrient solution was same but the temperature different by about 2$^{\circ}C$. Average day temperature, relative humidity, and $CO_2$ concentration were higher by 2.9$^{\circ}C$, 6%, and 200 ppm in the greenhouse for aquaculture with nutrient culture, respectively. Net assimilation rate of vegetables in the greenhouse was a little higher for aquaculture with nutrient culture than for nutrient culture only. Therefore, provided aquaculture and nutrient culture are carried out in the same greenhouse, the saving effect of heating cost as well as the additional promotive effects of vegetable and tilapia growth can be obtained.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.292-297
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• 1999

This study was performed to estimate the possibility of use of plant materials as catalytic agents fur the decontamination of waste waters contaminated with organic pollutants by using 2,4-dichlorophenol(2,4-DCP) as a model pollutant. Plant materials containing high peroxidase activity were selected as catalysts for the removal of 2,4-DCP. Peroxidase activity, which plant materials were containing, was measured, and the greatest peroxidase activity was observed in shepherd's purse, followed by turnip, sweet potato, Chinese cabbage and white radish. The peroxidase activity in shepherd's purse was four times higher than that of horseradish purchased in U.S.A. Using shepherd' s purse and turnip, it was investigated the effect of various factors on the decontamination of 2,4-DCP through oxidative coupling. The removal of 2,4-DCP was extremely fast, and a maximal removal could be achieved within 3 min for shepherd' s purse and 15min for turnip. The pH range was from 3.0 to 8.0 and the amount of $H_2O_2$ added was 9mM when maximal removal was achieved(over 90%). No increasing removal of 2,4-DCP was observed due to increasing the amount of $H_2O_2$ added (over 9mM). The initial concentration affected the transformation of 2,4-DCP incubated with plant materials. When turnip was used as catalytic agent, it was observed decreasing transformation of 2,4-DCP due to increasing initial concentration.

• Korean Journal of Environmental Agriculture
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• v.12 no.3
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• pp.247-254
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• 1993

The growth responses of Chinese Cabbage, lettuce, and spinach were evaluated to investigate the feasibility of carbonized rice-hulls as a sanitary cultivation media instead of soil. The carbonized rice-hulls were pretreated with several inorganic acid such as nitric, sulfuric, hydrochloric, and phosphoric acid for neutralization. The neutralization of the carbonated material using nitric, sulfuric, and phosphoric acid did not alter the growth responses of these vegetables compared to those of control plants grown on the normal cultivation soil. Especially, the nitric acid pretreatment resulted in the better growth of these plants than the mixture of soil and compost. This is probably due to the additional supply of the nitrate-nitrogens. However the growth responses of lettuce and spinach on the carbonated materials neutralized with hydrochloric acid were different and appeared to be having symptom which is analogous to the chloride toxicity during the late stage of growing. Although no difference was observed in chemical composition, the contents of protein-nitrogen were higher in the plants grown on the carbonated material compared to those of plant grown on the mixture of soil and compost. Based on our preliminary results, the carbonized and neutralized rice-hulls are very useful bed material for the sanitary cultivation under the controlled environmental condition.

• Journal of the Korean Society of Food Culture
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• v.4 no.2
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• pp.161-166
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• 1989

This study was intended to observe the changes of the nitrate, nitrite and vitamin C content during the fermentation of Kimchies by some added materials. Eight different types of Kimchi, were prepared with chinese cabbage and seasonings, to which added respectively materials such as soused anchovy, soused shrimp, garlic, mustard leaf, K-sorbate, ascorbic acid, radish. After they were prefermented at $18^{\circ}C$ for 24 hours, stored 35 days at $4^{\circ}C$. Generally optimal maturity of Kimchi showed pH 4.4 to 4.6, lactic acid content 0.3 to 0.4% at salt content belows 2.5%. The content of total vitamin C in Kimchies was approximately 19.8-24.7 mg/100g at the initial stage of fermentation and then slightly decreased. When the process of the fermentation was active, the content of total vitamin C increased up to the same level or higher than that of the initial stage and then gradually decreased. In the case of Kimchi which added garlic, the content of vitamin C was relatively higher then the other samples. In the initial stage of fermentation, the nitrate and nitrite content in the Kimchi which added garlic and raddish were relatively higher than other samples. Nitrate content reached its minimum by the 21st day, at that time content was 290-342 ppm. At this time, the nitrite was not detected and total vitamin C content in all samples decreased.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.110-116
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• 1997

Growth curves of seven strains of lactic acid bacteria isolated from Kimchi were graphed during cultivation at 1$0^{\circ}C$, 2$0^{\circ}C$, 3$0^{\circ}C$ and 4$0^{\circ}C$ in filter sterilized Chinese cabbage juice, and then lag time and generation time at each conditions were calcurated. At 3$0^{\circ}C$, the lag time of Leu. mesenteroides subsp. dextranicum was 168 min(minutes), Leu. mesenteroides subsp. mesenteroides 204 min, Leu. paramesenteroides 612 min, Lac. bavaricus 258 min, Lac. homohiochii 228 min, Lac. plantarum 270 min and Lac. brevis 264 min. And at this temperature, the generation times of Leu. mesenteroides subsp. dextranicum and Leu. mesenteroides subsp. mesenteroides were all 36 min, Lac. bavaricus 33 min, Lac. homohiochii 39 min, Lac. plantarum 66 min, Lac. brevis 42 min and Leu. paramesenteroides 162 min. As cultural temperature was lowed from 3$0^{\circ}C$ to 1$0^{\circ}C$, all strains showed remarkable prolongations in lag time and in generation time, and the prolongations were most conspicuous in Lac. plantarum. At 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$, both the lag time and the generation time of Leu. mesenteroides subsp. mesenteroides were shorter than those of Lac. plantarum. But at 4$0^{\circ}C$, this pattern was completely inverted. As a whole lower temperatures were more favorable for the growth of Leu. mesenteroides subsp. mesenteroides, while higher temperatures were for Lac. plantarum.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.149-153
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• 1989

Polygalacturonase(PG) and pectinesterase(PE) were extracted from Chinese cabbage and physicochemical properties of the enzymes were characterized. The preheating conditions for maximum retention of Kimchi texture were also studied. The activity of PE was highest at $50^{\circ}C$ and at 0.02M $CaCl_2$ but decreased in 0.2M $CaCl_2$, PG exhibited maximum activity at $65^{\circ}C$ with 0.3mM $CaCl_2$ but was inhibited by $CaCl_2$ at 0.5mM. Both of the enzymes, however, exhibited the maximum activity with 0.25M NaCl. Optimum preheating treatment was determined for minimum PG activity and maximum PE activity. Thus a maximum crispness and firmness was obtained with preheating in 0.05M $CaCl_2$ solution at $50^{\circ}C$ for 1.5hr results indicated that PE activity and calcium ion were very effective in preserving firmness.