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Residual Activity and Effect of Soil Applied Herbicides on Succeeding Crops in Vegetable Field - 1. Residual Activity and Effect of Applied Herbicides on Succeeding Crops in Winter Crops - (주요(主要) 채소용(菜蔬用) 제초제(除草劑)의 토양중(土壤中)에서의 잔효(殘效)와 후작물(後作物)에 미치는 영향(影響) - 제(第)1보(報) 월동작물(越冬作物)에 처리(處理)한 제초제(除草劑)의 잔효(殘效)와 후작물(後作物)에의 영향(影響) -)

  • Ryang, H.S.;Moon, Y.H.;Choi, E.S.;Jang, M.S.;Lee, J.H.
    • Korean Journal of Weed Science
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    • v.11 no.1
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    • pp.32-49
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    • 1991
  • Residual period and carry-over effect of some herbicides were determined using a bioassay method in five winter crops (chinese cabbage, radish, spinach, onion and garlic). The effects were measured at regular time intervals after applling different rates of the herbicides. There were no great differences in residual period and carry-over injury between the soils and kinds of crops used. However, the residual period varied with the herbicides studied and the carry-over injury was rate of the herbicide application, sampling depth of soil, and kind and seeding date of the test plant. When the residual herbicides were applied, the carry-over injury could be minimized by selecting tolerant crops, delaying seeding of the crops after application of the herbicides, and regulating the cultivation depth. Herbicides which showed no residual effect by the end of the cropping period (200-240 days for winter crops) and no carry-over effect were alachlor, trifluralin, ethalfluralin and prometryn. When pendimethalin, metolachlor, linuron and methabenthiazuron were applied at the recommended rate or less, there was no carry-over injury at harvesting time. With doubling the recommended rate, however, the carry-over effect was found in sensitive crops. Napropamide applied in winter crops at rate of 150-300g a.i./10a brought about carry-over injury for such Gramineae as Italian ryegrass, direct-seeded rice and barley, whereas the injury was not found in lowland-transplanted rice, Cruciferae, Cucurbitaceae and Solanaceae. Long residual herbicide nitralin applied at the rate of 75g a.i./10a caused the carry-over injury for Italian ryegrass, direct-seeded rice, baley and lowland-transplanted rice at 275 days in winter crops. In addition, a slight injury occurred in sesame, perilla and spinach, However, there was no injury for Cruciferae, Cucurbitaceae and Solanaceae.

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Physiological Characteristics of Starter Isolated from Kimchi and Fermentation of Tofu with Isolated Starter (발효두부 제조용 Starter의 선발과 이를 이용한 두부의 발효특성)

  • Kang, Kyoung Myoung;Lee, Shin Ho
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.41 no.11
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    • pp.1626-1631
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    • 2012
  • Sixty strains of lactic acid bacteria were isolated from kimchi and used as a starter for fermented tofu. Among the isolated strains, strain KL-6 showed antimicrobial activity against various pathogens, antioxidative activity, and viability in artificial gastric juice and artificial bile acid. The selected strain KL-6 was identified as Pediococcus acidilactici KL-6 by morphological and physiological tests, including Gram staining, catalase test, and 16S rRNA sequencing. The fermentation characteristics of tofu with a kimchi ingredient mixture (Control) consisting of red pepper, garlic, ginger, sugar, salt, jeotgal, and juice of chinese cabbage were compared with those of tofus inoculated with strain KL-6 and the kimchi ingredient mixture (TL) or a pre-fermented kimchi ingredient mixture (TPL) for 24 hr at $37^{\circ}C$. The pH levels of all tested tofu samples decreased after 1 week of fermentation, reaching 3.96 (control), 3.97 (TL), and 4.03 log cfu/g (TPL) after fermentation for 14 weeks at $20^{\circ}C$. Total aerobe content of fermented tofu increased until 2 weeks of fermentation, but decreased steadily thereafter. The number of lactic acid bacteria reached $10^6$ cfu/g after 1 week of fermentation in TL and TPL, whereas it took 2 weeks for the control. The number of lactic acid bacteria in all tested tofu samples reached $10^3$ cfu/g after 14 weeks of fermentation at $20^{\circ}C$. Coliform bacteria were not detected in TL or TPL after 1 week of fermentation. The sensory scores of TL and TPL were higher than that of control in terms of taste, flavor, texture, and overall acceptability. The sensory quality of TPL was the best among all tested fermented tofu samples.

Influence of Daytime Temperature on the Time Required for Fruit Harvest and Yield of Hot Pepper (주간온도가 고추의 수확 소요일수 및 수량에 미치는 영향)

  • Lee, Sang-Gyu;Choi, Chang-Sun;Lee, Jun-Gu;Jang, Yoon-Ah;Nam, Chun-Woo;Lee, Hee-Ju;Suh, Jeong-Min;Kang, Jum-Soon
    • Journal of Environmental Science International
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    • v.22 no.9
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    • pp.1181-1186
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    • 2013
  • Due to climate change, the occurrence of abnormal weather conditions has become more frequent, causing damage to vegetable crops grown in Korea. Hot pepper, Chinese cabbage and radish, the three most popular vegetables in Korea, are produced more in the field than in the greenhouse. It has been a trend that the time for field transplanting of seedlings is getting earlier and earlier as the spring temperatures keep rising. Seedlings transplanted too early in the spring take a longer time to resume the normal growth, because they are exposed to suboptimal temperature conditions. This study examined the influence of air temperature during seedling growth on the time required to reach the first fruit maturity and yield of hot pepper. Seedling plants of 'Super Manita' hot pepper was grown in temperatures $2.5^{\circ}C$ and $5.0^{\circ}C$ lower than the optimum temperature (determined by the average of temperatures for the past 5 years). Seedlings were transplanted into round plastic containers (30-cm diam., 45-cm height) and were placed in growth chambers in which the ambient temperature was controlled under natural sunlight. The growth of seedlings under lowered temperatures was reduced compared to the control. The mineral (K, Mg, P, N) concentrations in the leaf tissues were higher when plants were grown with the ambient temperature $2.5^{\circ}C$ lower than the optimum, regardless of changes in other growth parameters. Tissue calcium (Ca) concentration was the highest in the plants grown with optimum temperature. The carbohydrate to nitrogen (C/N) ratio, which was the highest (18.3) in the plants grown with optimum temperature, decreased concomitantly as the ambient temperature was lowered $2.5^{\circ}C$ and $5.0^{\circ}C$. The yield of the early harvested fruits was also reduced as the ambient temperature became lower. The first fruit harvest date for the plants grown with optimum temperature (June 27) was 13 days and 40 days, respectively, earlier than that in plants grown with $2.5^{\circ}C$ (July 10) and $5.0^{\circ}C$ (Aug 6) lower ambient temperatures. The fruit yield per plant for the optimum temperature (724 g) was the greatest compared to those grown with $2.5^{\circ}C$ (446 g) and $5.0^{\circ}C$ (236 g) lower temperatures. The result of this study suggests that the growers should be cautioned not to transplant their hot pepper seedlings too early into the field, since it may delay the time of first harvest eventually reducing total fruit yield.

Rapid Detection Method for Human Rotavirus from Vegetables by a Combination of Filtration and Integrated Cell Culture/Real-Time Reverse Transcription PCR (Filtration과 Integrated Cell Culture/Real-Time Reverse Transcription PCR 기법을 이용한 채소류에서 Human Rotavirus 신속 검출)

  • Hyeon, Ji-Yeon;Chon, Jung-Whan;Song, Kwang-Young;Hwang, In-Gyun;Kwak, Hyo-Sun;Lee, Jung-Soo;Kim, Moo-Sang;Lee, Jung-Bok;Seo, Kun-Ho
    • Korean Journal of Microbiology
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    • v.47 no.2
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    • pp.117-123
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    • 2011
  • The purpose of this study was to evaluate and compare different elution and concentration methods for optimization of human rotavirus (HRV) detection method using real-time RT-PCR and cell culture techniques. The leafy vegetable samples (lettuce, Chinese cabbage) were artificially inoculated with HRV. Viruses were extracted from the vegetables by two different elution buffers, buffer A (100 mM Tris-HCl, 50 mM glycine, 3% beef extract, pH 9.5) and buffer B (250 mM Threonine, 300 mM NaCl, pH 9.5), and the extracted viruses were concentrated by filtration and PEG precipitation sequentially. To determine infectivity of the viruses, the viruses recovered from the samples were infected to the MA-104 cells, and integrated cell culture real-time RT-PCR was performed at 1, 48, 72, 96, 120, 144, 168 h post-infection (p.i.). The elution buffer A was more efficient in extracting the virus from the produce samples tested than the buffer B, 29.54% and 18.32% of recoveries, respectively. The sensitivity of real-time RT-PCR method was markedly improved when the virus was concentrated by the filtration method. When the viruses were eluted and concentrated by buffer A and filtration, respectively, the average recovery rate was approximately 51.89%. When the viruses recovered from samples were infected to MA-104 cell, infectious HRV was detected within 48 h p.i. by ICC/real-time RT-PCR, whereas cytopathic effects were not observed until 72 h p.i. The optimized detection method evaluated in this study could be useful for rapid and reliable detection of HRV in fresh produce products and applied for detection of other food-borne viruses.

Microbial and Pathogenic Contamination of Ready-to-eat Fresh Vegetables in Korea (한국에 유통중인 신선편이 채소류의 미생물 품질 및 병원성 세균의 오염도 조사)

  • Bae, Young-Min;Hong, Yu-Jin;Kang, Dong-Hyun;Heu, Sung-Gi;Lee, Sun-Young
    • Korean Journal of Food Science and Technology
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    • v.43 no.2
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    • pp.161-168
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    • 2011
  • The purpose of this study was to evaluate microbiological contamination of fresh vegetables in Korea. Twenty types of vegetables were tested for total aerobic bacteria, coliforms, Escherichia coli, yeast and mold, and pathogenic bacteria such as Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Salmonella, E. coli O157:H7, Cronobacter sakazakii, Shigella, and Campylobacter. Levels of total aerobic bacteria and coliform on 20 vegetables were between 3.74 and 8.04 log CFU/g, and 0.16 and 5.02 log CFU/g, respectively. The highest contamination levels of total aerobic bacteria were observed on water dropwort, sprouts, mungbean sprout, and ballflower root. There was no significant difference (p>0.05) in microbial contamination levels of total aerobic count, coliform, E. coli, yeast and mold between organic and nonorganic vegetables. When isolation methods using selective agars were applied, L. monocytogenes, B. cereus, Salmonella and Campylobacter were isolated from some fresh vegetable samples. Results of API kit tests showed that L. monocytogenes was identified on Chinese cabbage, cucumber, soybean sprouts, and iceberg lettuce while Salmonella was identified on Korean leek. Furthermore, Campylobacter jejuni was also identified in more than 50 of the 100 samples. However, when positive samples from API kit were tested for real-time PCR or 16S rRNA sequencing method, only B. cereus from perilla leaf, carrot, water dropwort, and sprouts showed positive results. These results indicate that selective agar and API kit detection methods might result in false positive results for some pathogens. Therefore, studies need to improve isolation or confirmation methods for such pathogens.

Efficiency of microspore embryogenesis in Brassica rapa using different genotypes and culture conditions (배추 유전자원의 소포자 유래 배 발생 효율에 미치는 배양 조건 구명)

  • Seo, Mi-Suk;Sohn, Seong-Han;Park, Beom-Seok;Ko, Ho-Cheol;Jin, Mina
    • Journal of Plant Biotechnology
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    • v.41 no.3
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    • pp.116-122
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    • 2014
  • Total of fifty accessions of Brassica rapa with various morphological characteristics were used for production of double haploid plants though microspore culture in Brassica rapa. Among them, only 30 accessions induced embryos from microspores. The highest efficiency of embryo induction of 1.194 per bud was obtained from IT135449 of turnip type, while 3 accessions of sarson (winter oil) type did not generate embryo. The effect of heat shock periods for embryogenesis was also investigated with 4 accessions (IT135449; Turnip type, IT199710; Chinese cabbage type, IT212886; Pak choi type, IT218043; Summer oil type). The high productions of embryos were observed in IT135449, IT199710 and IT212886 when microspores were pre-cultured to $32^{\circ}C$ for 2 days. In IT218043, high embryogenesis was observed at the 3 days of heat shock treatment. The optimal condition of shoot regeneration for IT199710 was observed in MS medium supplemented with NAA $0.5mg{\cdot}L^{-1}$ and BAP $1mg{\cdot}L^{-1}$. In contrast, the IT135449 and IT212886 were observed high regeneration frequency in MS medium without plant growth regulators. All the plantlets regenerated from microspore-derived embryos have been successfully transplanted to soil, and bud self-pollinated seeds were produced from doubled haploid plants. This indicated that double-haploid genotype was likely generated naturally during embryogenesis process.

Determination of Fomesafen Residue in Agricultural Commodities Using HPLC-UVD/MS (HPLC-UVD/MS를 이용한 농산물 중 fomesafen의 분석)

  • Lee, Su-Jin;Hwang, Young-Sun;Kim, Young-Hak;Nam, Mi-Young;Hong, Seung-Beom;Yun, Won-Kap;Kwon, Chan-Hyeok;Do, Jung-A;Im, Moo-Hyeog;Lee, Young-Deuk;Choung, Myoung-Gun
    • The Korean Journal of Pesticide Science
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    • v.14 no.2
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    • pp.95-103
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    • 2010
  • Fomesafen is a selective herbicide, and used to control annual and perennial broad-leaf grass on soybean and fruit fields in USA and China, but not introduced in Korea yet. So, MRL (Maximum Residue Level), and analytical method of fomesafen were not establishment in Korea. Therefore, this experiment was conducted to establish a determination method for fomesafen residue in crops using HPLC-UVD/MS. Fomesafen residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and dichloromethane partition was followed to recover fomesafen from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The fomesafen was quantitated by HPLC with UVD, using a Shiseido CAPCELL-PAK UG C18 column. The crops were fortified with fomesafen at 3 levels per crop. Mean recovery ratio were ranged from 87.5% for a 0.4 ppm in hulled rice to 102.5% for a 0.4 ppm in apple. The coefficients of variation were ranged from 0.6% for a 2.0 ppm in hulled rice to 7.7% for a 0.04 ppm in green pepper. Quantitative limit of fomesafen was 0.04 mg/kg in representative 5 crop samples. A LC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of fomesafen in agricultural commodities.

Monitoring of Pesticide Residues in Leafy Vegetables Collected from Wholesale and Traditional Markets in Cheongju (청주지역 도매 및 재래시장 유통 엽채류 중 잔류농약 모니터링)

  • Noh, Hyun-Ho;Park, Young-Soon;Kang, Kyung-Won;Paik, Hyo-Kyung;Lee, Kwang-Hun;Lee, Jae-Yun;Yeop, Kyung-Won;Choi, Song-Rim;Kyung, Kee-Sung
    • The Korean Journal of Pesticide Science
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    • v.14 no.4
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    • pp.381-393
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    • 2010
  • In order to monitor the residual characteristics of the pesticides in leafy vegetables selling at wholesale markets and traditional markets in Cheongju, a total of 180 samples of 15 leafy vegetables, such as broccoli, celery, chard, chicory, Chinese vegetable, Chwinamul, crown daisy, Korean cabbage, leek, lettuce, perilla leaves, Shinsuncho, spinach, welsh onion and young radish, were purchased from the wholesale markets and traditional markets in June and August in 2010 and the pesticide residues in them were analyzed by multiresidue analysis method using GLC, HPLC and GC-MSD. Seven pesticides were detected from 12 samples out of total 180 samples collected, representing detection rate was 6.7%. In case of the samples collected from markets in June, four pesticides including tefluthrin were detected from six samples and in case of the samples collected from markets in August, three pesticides including pendimethalin were detected from three samples. The MRL-exceeding rate of pesticides detected from leafy vegetables was 0.6%. The pesticide exceeded its MRL was azoxystrobin detected from crown daisy and many pesticides were not registered to the crops, excepting that azoxystrobin detected from Chwinamul and tefluthrin from leek. Estimated daily intakes (EDIs) of the pesticides detected from leafy vegetables were less than 7% of their acceptable daily intakes (ADIs), representing that residue levels of the pesticides detected were evaluated as safe.

Development of Analytical Method for Fenoxycarb, Pyriproxyfen and Methoprene Residues in Agricultural Commodities Using HPLC-UVD/MS (HPLC-UVD/MS를 이용한 농산물 중 fenoxycarb, pyriproxyfen 및 methoprene의 분석법 확립)

  • Lee, Su-Jin;Kim, Young-Hak;Song, Lee-Seul;Hwang, Yong-Sun;Lim, Jung-Dae;Sohn, Eun-Hwa;Im, Moo-Hyeog;Do, Jung-Ah;Oh, Jae-Ho;Kwon, Ki-Sung;Lee, Joong-Keun;Lee, Young-Deuk;Choung, Myoung-Gun
    • The Korean Journal of Pesticide Science
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    • v.15 no.3
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    • pp.254-268
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    • 2011
  • Fenoxycarb, pyriproxyfen and methoprene are juvenile hormone mimic insecticide. These insecticides have been widely used for mosquito, fly, scale insects, and Lepidoptera. The purpose of this study was to develop a simultaneous determination procedure of fenoxycarb, pyriproxyfen and methoprene residues in crops using HPLC-UVD/MS. These insecticide residues were extracted with acetone from representative samples of four raw products which comprised brown rice, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and then n-hexane/dichloromethane partition was followed to recover these insecticides from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The analytes were quantitated by HPLC-UVD/MS, using a $C_{18}$ column. The crops were fortified with each insecticide at 3 levels per crop. Mean recovery ratios were ranged from 80.0 to 104.3% in four representative agricultural commodities. The coefficients of variation were less than 4.8%. Quantitative limit of fenoxycarb, pyriproxyfen, and methoprene was 0.04 mg/kg in crop samples. A HPLC-UVD/MS with selected-ion monitoring was also provided to confirm the suspected residues. The proposed simultaneous analysis method was reproducible and sensitive enough to determine the residues of fenoxycarb, pyriproxyfen and methoprene in the agricultural commodities.

Determination of cyromazine residues in agricultural commodities using HPLC-UVD/MS (HPLC-UVD/MS를 이용한 농산물 중 Cyromazine의 잔류분석법)

  • Song, Lee-Seul;Kim, Young-Hak;Lee, Su-Jin;Hwang, Young-Sun;Kwon, Chan-Hyeok;Do, Jung-Ah;Oh, Jae-Ho;Im, Moo-Hyeog;Chang, Woo-Suk;Lee, Young-Deuk;Choung, Myoung-Gun
    • The Korean Journal of Pesticide Science
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    • v.16 no.3
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    • pp.202-208
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    • 2012
  • A high-performance liquid chromatographic (HPLC) method was developed to determine residues of cyromazine, a triazine insecticide, in agricultural commodities. Cyromazine was extracted with 90% aqueous methanol from representative crops which comprised brown rice, oyster mushroom, oriental melon, watermelon, and Chinese cabbage. Following to evaporation of methanol in the extract, the aqueous concentrate was acidified to form the protonated cyromazine. Dichloromethane partition was then applied to remove nonpolar co-extractives in the aqueous phase. Strong cation-exchange chromatography using Dowex 50W-X4 resin was employed for final purification of the extract. Cyromazine was successfully separated on a Zorbax SB-Aq $C_{18}$ column showing high retention for polar compounds. Cyromazine was sensitively quantitated by ultraviolet absorption at 214 nm. Limit of quantitation (LOQ) of the method was 0.04 mg/kg irrespective of sample types. Each crops were fortified at 3 different concentrations of cyromazine for recovery test. Mean recoveries from samples fortified at LOQ~2.0 mg/kg in triplicate ranged 80.2~103.3% in five agricultural commodities. Relative standard deviations in recoveries were all less than 6%. A selected-ion monitoring LC/MS method with electrospray ionization in positive-ion mode was also provided to confirm the suspected residue. The proposed method was reproducible and sensitive enough to routinely determine and inspect the residue of cyromazine in agricultural commodities.