• Korean Journal of Weed Science
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• v.16 no.4
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• pp.317-326
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• 1996

To know whether pyrazosulfuron-ethyl(PYR) and imazaquin(IMA), known as a acetolactate synthase(ALS) inhibitors, have a same herbicidal action pattern in rice(Oryza sativa) or barnyardgrass (Echinochloa crus-galli), an inhibition pattern and a response characteristics in combination with dymron or butachlor were investigated. In contrast to the phytotoxicity of rice treated with IMA, the one treated with PYR was completely tended to be recovered after 25 days after treatment. Safening effect of dymron against PYR was effectively developed to transplanted-rice, while such an effect was not shown in combination with IMA. In combination with PYR and butachlor, antagonistic effect was observed in both simultaneous or sequential treatment on bamyardgrass, however, additive effect was rather shown in combination with IMA and its activity was dominantly dependent on the first applied compound. $I_{50}$ of PYR and IMA on the ALS extracted from barnyardgrass was $4{\times}10^{-7}$M and $2.8{\times}10^{-6})$M, respectively. Butachlor did not affect their activities on ALS in vitro. These results suggest that PYR and IMA might have a different action each other in the pathway to a final herbicidal activity even though their primary action site is ALS.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.114-121
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• 1993

Differences in need occurrence and competition were investigated among five types of rice(Oryza sativa L.) cultivation. Dry weights of weeds in between transplanting and/or seeding and heading date showed in the decreasing order of dry direct-seeded, flood direct-seeded, machine transplanting with 10-day-old seedling, machine transplanting with 30-day-old seedling, and conventional hand transplanting. A similar trend was obtained with application of weedy followed by weed-free. Weed-free periods allowed to decrease by 20% dry weight of rice were 3 weeks after transplanting(WAT) in transplanting cultivations, 5 weeks after seeding(WAS) in wet direct-seeded rice, and 7-8 WAS in dry direct-seeded rice. On the other hand, weedy periods as determined by the same criterion were 9 WAT in conventional hand transplanting and machine transplanting with 30-day-old seedling, 7 WAT in machine transplanting with 10-day-old seedling, 8 WAS in dry direct-seeded rice, and 6 WAS in flood direct-seeded rice.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.2
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• pp.125-130
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• 2012

This study was performed to investigate the nutritive values of white panicled rice (Oryza sativa L., WPR) silage manufactured with WPR grown in reclaimed paddy field of Bigumdo of Korea in 2011. The WPR used in this study were collected in 1,000 ha of reclaimed paddy field of Bigumdo and was harvested at dough stage and ensiled. The yield of whole crop rice (WCR) grown in region received the most severe damage (MSD) was lower as about 800 kg/ha as than that in region of normal growth (NG). The content of crude protein and total digestible nutrient in WCR of MSD slightly increased, as compared to that in WCR of NG, but the contents of acid detergent fiber and neutral detergent fiber significantly decreased (p<0.05). The pH in WCR silage of MSD and NG ranged from 4.5 to 5.0 and pH decreased by the inoculation of lactic bacteria (p<0.05). The content of lactic acid in WCR silage of MSD and NG increased by the inoculation of lactic bacteria (p<0.05), but the content of acetic acid and butyric acid decreased (p<0.05). Flieg's score in WCR silage of MSD and NG inoculated lactic bacteria increased from 2 to 3 grade, as comparing to non-inoculation of lactic bacteria. Therefore, this study suggests that WPR can be utilized as forage.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.52-56
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• 2000

The influence of the 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenyl- propionamide derivatives on the herbicide activities against rice plant with pre-emergence and post-emergence in down land were examined and the structure activity relationship (SAR) were analyzed by Free-Wilson and Hansch method. In pre-emergence, the SAR approach is shown that the optimal, $({\pi})_{opt}=0.91$, hydrophobicity with electron donating effect of the ortho substituted mono substituents and 2,3,4-substituted three substituents were found to be contribute the herbicidal activity. Whereas, in post-emergence, the optimal, ({\pi})_{opt}=0.50$, hydrophobicity with electron withdrawing effect of meta substituted mono subsituents and 2,3-substituted two substituents were found to be contribute the herbicide activity. The herbicide activities with post-emergence more increase than that of pre-emergence. It is assumed from the SAR equations that the 2-methyl-3-methoxy-4-cyano group substituent is selected as the most lowest herbicide activity against rice plant with post-emergence in green house. The hydrolysis reaction was proceeded through nucleophilic addition-elimination (Ad_{Nu-E})$ with the orbital control between LUMO of substrate and HOMO of water molecule. And molecular electrostatic potential (MEP) of none (H) substituent was discussed.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.12-17
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• 2000

For the enzymatic production of $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid (AA-2G) from ascorbic acid, rice seed was used as the source of ${\alpha}-glucosidase$ having transglucosylation activity. Among six rice varieties, cultivated in Korea, ${\alpha}-glucosidase$ activity of Oryza savita L. cv. Ilpumbyeo was the highest with 125.03 unit/ml and it had maximum specific activity with 8.52 unit/mg protein when rice seeds were grown for 3 days after germination. For the production of AA-2G using crude extract of O. savita L. cv. Ilpumbyeo, maltose was most effective glucose donor. The optimum concentration of maltose and ascorbic acid were 125 mM and 175 mM, respectively. The optimum concentration of ${\alpha}-glucosidase$ was 100 unit. The most effective buffer was 100 mM sodium citrate. The optimum pH and temperature were 5.0 and $60^{\circ}C$, respectively. Under the optimum condition, $108.43\;{\mu}M/unit$ of AA-2G was produced from ascorbic acid after 35 minutes of reaction, which corresponds to 6.2% of conversion ratio based on the amount of ascorbic acid used.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.3
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• pp.205-212
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• 2015

Farmers with forage barley (Hordeum vulgare L.)-rice (Oryza sativa L.) cropping system at reclaimed tidal lands burn crop residues to facilitate seedbed preparation or remove them for feed stock. This study was conducted to investigate the effect of rice straw amendment and N fertilization on soil properties and N uptake of rice under forage barely-rice cropping system at reclaimed tidal paddy field. Rice straw was applied at the rates of 0, 2.5 and $5.0ton\;ha^{-1}$ and N was fertilized at 0, 100, 200 and $400kg\;ha^{-1}$. Although there was no significant difference in the growth and yield of rice, fresh and dry weight of forage barely increased with increasing the amount of rice straw. The amount of N uptake of rice at harvesting stage was $65.8-69.2kg\;ha^{-1}$ by the amount of rice straw amendment, but there were no significant differences among rice straw amendment levels. After harvesting the rice, the soil salinity decreased with rice straw amendment compared to the control. After forage barely and rice cultivation, soil organic matter contents increased to $2.6-2.8g\;kg^{-1}$ and $3.2-3.5g\;kg^{-1}$, respectively. The amount of N uptake of rice at harvesting stage increased up to $82kg\;ha^{-1}$ in $400kg\;ha^{-1}$ N applied plots which were $37.8kg\;ha^{-1}$ higher than the control. Nitrogen fertilization decreased N recovery efficiency. The highest yield of rice was observed at $244kg\;ha^{-1}$ N fertilization level, but the optimum N level was estimated at $168kg\;ha^{-1}$ in order to keep the protein content of rice under 6.5%. Further researches on N uptake and application of organic matter according to soil salinity will be necessary to increase N use efficiency at reclaimed tidal paddy field.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.154-167
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• 1989

This study was conducted to determine the influence of various extracts from 21 medicinal plants including Bupleurm falcatum on the germination and growth of Lactuca sativa, Oryza native and E. crus-galli var. crus-galli, and the amount of their phenolic acids, fatty acids and organic acids, Water extract(5%) of all the medicinal plants, particularly Acorus gramineus, Cnidium officinale, Aconitum carmicheali, Bulpeurum falcatum, Zingiber officinale, Angelica gigas and Curcuma zeodaria inhibited over 90% of the lettuce seed germination and growth, indicating that medicinal plants contained the biologically active substances. The highest amount of phenolic compounds was observed in Prunus crmenica var, ansu(30.6013mg/g) followed by Aconitum ciliare(29.1008mg/g) and Cnidium officienale(27.2943mg/g) which inhibited markedly the germination of testing plants, showing the close relation of phenolic compounds to inhibitory effects. Cnidium officinale contained the highest amount of fatty acids(24.10mg/g) and organic acids(21.04mg/g) which may be partly related to inhibitory effects.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.141-148
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• 1989

Echinochloa species collected from 13 places of Korea appeared to be morphologically very different. They were classified by Yabuno's seed morphology method into two species such as Echinochloa oryzicola and Echinochloa crus-galli which have two varieties such E. crus-galli var, cuss-galli and var, praticola. Among them, E. oryzicola was morphologically similar to Oryza sativa, but it had small leaf length with straight from, no awn, late heading and little interspecific variance. As compared with E. oryzicola, E. eras-galli var. crus-galli, and var, praticola showed a great variance exerting so difficulty in classifing them morphologically, particularly a great variance in leaf length, tiller number and grain size. E. oryzicola species showed the more sensitive response to butachor and thiobencarb herbicides than E. eras-galli var. praticola and var. eras-galli. However, E. eras-galli var. praticola was themore sensitive one to pretilachloa herbicide than such as E. oryzicola and E. eras-galli var. eras-galli, indicating that Echinochloa species might have a selective response to the annual herbicides tested.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.46-53
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• 1995

The herbicidal activity of thiocarbamate herbicides and its effect on cell division and elongation were determined. The herbicides studied were molinate(S-ethyl-N,N-hexamethylenethiocarbamate), dimepiperate [S-(${\alpha}$,${\alpha}$-di methylbenzyle)piperidine-1-carbothioate], esprocarb [S-benzyl-N-ethyl-N-(1,2-dimethylpropyl) thiocarbamate], and thiobencarb [S-(4-chlorobenzyl)-N, N-diethylthiocarbamate]. The herbicides applied at the rates ranged from $10^{-6}$ to $10^{-5}M$ did not affect germination and post-germination root growth of rice(Oryza sativa L.) and barnyardgrass [Echinochloa crus-galli(L.) P. Beauv.], but inhibited the post-germination shoot growth. There was no inhibition of gibberellin-induced ${\alpha}$-amylase biosynthesis in de-embryonated rice seeds by the herbicides at $10^{-5}M$, but about 50-60% inhibition occurred at $10^{-4}M$. When the herbicides were applied 7 days after seeding, the rates required to 50% growth inhibition of barnyardgrass were 146g, 91g, 96g, and 102g ai/10a for molinate, dimepiperate, esprocarb, and thiobencarb, respectively. No effect of the herbicides on cell division was found at $10^{-4}M$, but about 31 to 47% inhibition as compared with the untreated check was obtained by treatment of the herbicides at $10^{-3}M$. However, about 33 to 38% inhibition of cell elongation occurred at $10^{-5}M$ of the herbicides. They also inhibited IAA-induced cell elongation.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.278-288
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• 1995

Weed species occurred in dry- and water-seeded rice were 14 (2 grasses, 8 broadleaves, and 4 sedges) and 12 species (1 grasses, 7 broadleaves, and 4 sedges), respectively. Dominant weed species in dry-seeded rice were Lindernia procumbens, Cyperus difformis, Cardamine flexuosa, and Cyperus serotinus in discending order. The species in water-seeded rice were Cyperus difformis, Scirpus juncoides, and Lindernia procumbens. The number of weed species emerged in direct-seeded rice was determined at about 45 days after seeding, and dry weights of weeds were increased up to 75~90 days after seeding. Timing for great increase of plant height varied depending upon weed species. Regardless of weed number emerged, the most dominant weeds until late stage of growth were Cyperus difformis, Bidens frondosa, Digitaria ciliaris and Echinochloa crus-galli in dry- seeded rice, and Cyperus difformis, Echinochloa eras-galli and Scirpus juncoides in water-seeded rice.