• Korean Journal of Weed Science
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• v.17 no.2
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• pp.192-198
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• 1997

This experiment was carried out to determine selectivity of herbicide cyhalofop-butyl ester on enzyme activity, biosynthesis of fatty acid and protein between rice and Echinochloa crus-galli. Activity of the acetyl-CoA carboxylase(ACCase) was inhibited greater in E. crus-galli than in rice by the treatment of cyhalofop-butyl ester. The ACCase activity in E. crus-galli was observed with $I_{50}$ at 1-2ppm of cyhalofop-butyl ester, while in rice only at above 10ppm. Cyhalofop-butyl ester also inhibited the biosynthesis of fatty acid by 61% of palmitic acid, 54% of linoleic acid and 41% of linolenic acid in E. crux-galli. In contrast, no significant difference of fatty acid content was observed in rice at 5DAT as compared with the untreated control. Protein patterns of rice between the herbicide treatment and the untreated control were not significantly different, but in E. crus-galli, 3 protein spots were disappeared in between 29KD and 45KD.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.52-58
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• 2011

In order to investigate an artificially transition method of perennial ryegrass(Lolium perenne L. 'Accent') overseeded on zoysiagrass (Zoysia japonca Zenith') with Kerb (3,5-jichloro-N (1,1-dimethyl-2-propynyl). We observed turfgrass growth and physiological responses of the two turfgrasses under the shading treatments. The experiment was conducted in greenhouse during April- August. Shading was generally using a black shade net product whose the shade level was done into 0, 35 and 75%, actual light intensities were 589, 378 and $135\;{\mu}mol{\cdot}m^{-2}{\cdot}s$ PAR, respectively. The four levels of Kerb treatment were 0, 0.1 0.2, and $0.4\;g{\cdot}m^{-2}$. As shading was getting increased, growth of perennial ryegrass was increased slowly, but zoysiagrass was reduced and almost all of experiments showed significant differences statistically. Perennial ryegrass exhibited inclination that growth was reduced in more than Kerb $0.4\;g{\cdot}m^{-2}$ by shades. On the other hand, it was shown that the growth of zoysigrass was reduced by shades largely and it was not effected by Kerb. Through this study, it was determined that Kerb is effective for elimination of overseeded perennial ryegrass on zoysiagrass. Moreover, when excluding perennial ryegrass under the condition like shade, it is desirable for treating high concentration more than the basic processing amount.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.59-64
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• 1998

In order to elucidate the leaching behaviour of the herbicide bentazon in soil, soil columns(5cm ID ${\times}$ 34 cm L) were packed with three different soils up to 30 cm height, followed by the treatment of [$^{14}C$]bentazon, and rice plants(Oryza sativa L.) were grown for 9 weeks on these columns, with the columns without growing rice plants as the control for comparison. The amounts of $^{14}C$ activities percolated were about 92% of the originally applied $^{14}C$ irrespective of the physicochemical properties of the soils in the absence of rice plants, whereas $21{\sim}50%$ of the originally applied $^{14}C$ was percolated in the presence of rice plants, suggesting that the amounts of $^{14}C$ leached decreased remarkably in rice-cultivating soils. Bentazon leached faster in soil with higher pH and with lower organic matter content in the presence of growing rice plants. The amounts of $^{14}CO_{2}$ evolved from the soil columns were less than 0.2% of the originally applied $^{14}C$. Smaller amounts of $^{14}C$ were translocated into shoots via roots in soils with higher organic matter content. $^{14}C$ activities distributed into the aqueous phase of the leachate collected from the soil columns increased with leaching period and by rice cultivation, whereas the physico-chemical properties of soils did not exhibit any effect. The amounts of soil-bound residues increased remarkably by cultivating rice plants.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.277-284
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• 1990

The response of rice (Oryza sativa L.) cultivars to mixtures of 2, 4-D(2, 4-dichlorophenoxyacetic acid) and other herbicides was investigated to determine if there was an interaction between them. When 2, 4-D was applied, shoot growth of Taipei 309 was more affected than that of IR28 at all concentrations used. In contrast, when thiobencarb (S-[(4-chlorophenyl)methyl]diethylcarbamothioate), butachlor [N-(buthoxymethyl) -2-chloro-N-(2, 6-diethylphenyl) acetamide], and glyphosate [N-(phosphonomethyl)glycine] were applied, the shoot growth of Taipei 309 was less affected than that of IR28 at all herbicide concentrations. Combination of 2, 4-D and the lowest thiobencarb concentration was antagonistic for shoot length for both cultivars, but at higher concentrations, it was synergistic. Synergism for shoot fresh weight between 2, 4-D and thiobencarb was observed with IR28 at all concentrations but, for Taipei 309, synergism was observed only at lower 2, 4-D concentrations. Mixing 2. 4-D with butachlor resulted in greater inhibition in shoot length and fresh weight of IR28 than Taipei 309 at all concentrations indicating a synergistic interaction. With combinations of 2, 4-D and glyphosate, an antagonistic interaction for shoot length was observed for both cultivars. A synergistic interaction for shoot fresh weight was observed with IR28 when combinations of the highest concentration of glyphosate and 2, 4-D were applied but there was an antagonistic interaction with Taipei 309.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.261-268
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• 1990

Various herbicides were applied to the young rice seedling from which endosperm were removed and their effects were determined at 40 days after transplanting. Generally, growth was retarded, but the number of tillers was not effected. Application of bensulfuron and pretilachlor showed slight growth inhibition compared to dimepiperate and pyrazolate. Injury due to herbicide application was dependent on the transplanting depth. Injury was severe when pretilachlor and pyrazolate were applied to rice transplanted 0 and 4cm deep, respectively. However, bensulfuron showed much injury regardless of transplanting depths with the tendency of general growth retardation. Dimepiperate was fairly safe at all transplanting depths. The application of herbicides at 3 and 6 DAT showed higher injury than that at g and 12 DAT. The degree of injury was severe when pretilachlor and bensulfuron were applied.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.337-345
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• 1996

This study was conducted to investigate the protox activity, the PPIX accumulation and the activity of antioxidative enzymes of the oxyfluorfen-tolerant and -susceptible rice cultivars by oxyfluorfen and oxytluorfen-similar herbicides treatment. When treated with acifluorfen, bifenox or oxadiazon, the oxyfluorfen-tolerant rice cultivars showed less decreased in fresh weight than the susceptible rice cultivars. The inhibition of protox activity was in the order of acifluorfen > oxyfluorfen > bifenox > oxadiazon, and the PPIX accumulation was in the sequence of oxadiazon > acifluorfen > oxyfluorfen > bifenox. The inhibition of protox activity and the PPIX accumulation by the herbicide was greater in the susceptible rice cultivars than in the tolerant rice cultivars. The effect inhibiting the decrease of chlorophyll content resulting from the treatment of GC, tetrapyrrole biosynthesis inhibitor, was in the order of oxyfluorfen > acifluorfen > bifenox > oxadiazon, and the tolerant rice cultivar had more than the susceptible rice cultivar. In the treatment of DPE and oxadiazon, the activities of MDAR, POX and GR was higher in the tolerant rice cultivar than in the susceptible rice cultivar, and in the case of POX isozyme the activities of main D and E bands increased in the tolerant rice cultivars at tested herbicides but they didn't in the susceptible rice cultivar.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.413-420
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• 1997

In this study, germination characteristics and effect of some chemicals on germination of Trapa japonica $F_{EROV}$ seeds were investigated to obtain a fundamental data for controlling them. When the seeds were stored at low temperature for at least 3 months, their dormancy was completely released with a germinability of above 90%. However, those stored under the room or high temperature condition were never germinated. Germination was best at constant temperature of around $25^{\circ}C$ or at alternate temperature of 25/$15^{\circ}C$ (12 hr-day/12 hr-night), and was nat dependent on light. They could germinate though planted at the depth of 15 cm, but their initial growth were: suppressed with increase of planting depth, especially above 10 cm depth. Germinability was lost when the fresh weight was decreased more than 30%, indicating that the seed is sensitive to dehydration. The freezing at $-20^{\circ}C$ for 1 hr didn't affect germination, but 5 hr treatment completely killed them. Their germination was inhibited by 100% at 100 ppm ABA and slightly inhibited above 25 ppm of butachlor, whereas pyrazosulfuron-ethylnt is likely to control T. japonica physically and herbicide treatment to inhibit germination may not be recommendatory. and bensulfuron-methyl didn't inhibit the germination at the concentration of 100 ppm. Taken together, dehydration treatme is likely to control T. japonica physically and herbicide treatment to inhibit germination may not be recommendatory.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1045-1053
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• 2000

The adsorption and desorption of herbicides such as napropamide and pendimethalin was studied in three kinds of soil. sandy loam. silty clay and loam. The results of batch tests performed with various shaking time, pH, organic matter content and temperature in soil were summarized as follows. The shaking times reached to the equilibrium of the adsorption and desorption for napropamide and pendimethalin in soil were 12 and 6 hours. respectively. For each soil. the adsorption rates of napropamide were 23.35%. 31.57% and 25.95%, the desorption rates of them were 18.42%, 13.42% and 15.89%, respectively. And the adsorption rates of pendimethalin were 59.61%, 77.26% and 64.02%, and the desorption rates of them were 3.23%, 2.93% and 3.07%, respectively. The adsorption isotherms with the Freundlich equation showed better consistency than those with the Langmuir one. The adsorption was affected by the organic matter content when it exceed 2.0%. But if the organic matter content is below 2.0%, it was affected by the clay content. When the organic matter content is 0.95~7.45%, the adsorption coefficients ($K_{fa}$) of napropamide and pendimethalin were 1.17~2.50 and 4.74~16.08 and the desorption coefficients($K_{fd}$) of them were 5.33~34.06 and 24.25~134.00, respectively. Because of the physical adsorption between herbicide molecules and soil surface, little effect of pH variation of soils was appeared for the adsorption and desorption. Because of the solubility of herbicide is related to the temperature, the adsorption rate was decreased and the desorption rate was increased with the temperature increase, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.3
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• pp.169-175
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• 1985

This experiment was carried out during 1983-1984 to determine an effective method for the introduction of pasture species on nonarable hill country without cultivation. In this experiment, 1.8 and 2.8kg a.i. $ha^{-1}$ rates of glyphosate and a 0.7kg a.i.$ha^{-1}$ rate of paraquat were applied, and also 30, 45 and 60 days intervals between spraying and sowing were used. Establishment of orchardgrass (Dactylis glomerata) was not affected by the application of herbicides, but that of ladino clover (Trifolium repens) was significantly affected by glyphosate and paraquat. It was found that glyphosate and paraquat have no apparent soil residual activity or pre-emergence effect when sprayed 30 to 60 days before sowing. Dry matter yield of pasture species on the herbicide treatments was significantly higher than that on the unsprayed treatments. The highest yield was obtained from the 1.8kg a.i.$ha^{-1}$ rate of glyphosate 45 days before sowing. Botanical analysis at the final cut showed that the shrubs and native grass of original site were reduced to 5% by glyphosate application, but those on the unsprayed control were still 51%. Crude protein content and in vitro dry matter digestibility of herbage on the herbicide treatments were higher than those on the unsprayed treatments. Results indicated that glyphosate was more effective to control resident shrubs and grass than paraquat, and good establishment and higher yield of surface-sown pasture species can be obtained by spraying 1.8 to 2.8kg a.i.$ha^{-1}$ of glyphosate, 30 to 45 days before sowing.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.107-116
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• 1998

Based on the differential growth response to exogenous gibberellic acid ($GA_{3}$) between semi-dwarf wheat(Triticum aestivum) and wild oat(Avena fatua), we examined the possibility of improving the selective performance of several herbicides by $GA_{3}$ application and the physiological background of $GA_{3}$-induced increase in herbicidal activity. Growth of wild oat was 4 to 5 times higher than that of wheat by $GA_{3}$ treatment. Pretreatment of wild oat seed with 300 ppm $GA_{3}$ increased the herbicidal activities of trifluralin and isoproturon by soil-surface application, but not of alachor and metsulfuron-methyl. $GA_{3}$ applied simultaneously with post-emergence herbicides resulted in a significant or moderate improvement of the efficacy of such herbicides as tralkoxydim, fenoxaprop-ethyl, metsulfuron-methyl, metribuzine and isoproturon, but not in the mixtures of oxyfluorfen or paraquat with $GA_{3}$. In the sequencial treatment of tralkoxydim and $GA_{3}$ at interval of one-day, $GA_{3}$ applied prior to tralkoxydim significantly increased a chlorosis and desiccation of leaf without affecting the growth inhibition by tralkoxydim. Tralkoxydim followed by $GA_{3}$ application had lower herbicidal activity than that of $GA_{3}$ followed by tralkoxydim treatment. Electrolyte leakage response of $GA_{3}$-pretreated or $GA_{3}$-untreated wild oat leaf against several compounds inducing membrane. peroxidation was compared. Differencial responses were observed in oxyfluorfen and isoproturon treatments with an increased electrolyte leakage in $GA_{3}$-pretreated tissue, but not in paraquat and rose bengal treatments. These results suggest that $GA_{3}$-induced increase in herbicidal activity is likely to be dependent on a herbicide type and may be due to activation of a metabolic ability related with herbicidal reponse as well as an increase in the herbicide absorbtion and translocation, rather than due to membrane and cell wall extention induced by $GA_{3}$, which in turn makes the herbicides easily enter.