• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.3
• /
• pp.195-198
• /
• 2000

Weedy rice has typical characters such as easy shattering, dormancy, and longevity. These characters let it undergo the winter and occur year by year, It is very difficult to control weedy rice once the field have contaminated with its seeds. Therefore, the control method for weedy rice was focused on the no-tillage direct seeding in this experiment. The germination ability of seeds shattered on the soil surface in the next spring was 92.7% in weedy rice, and 4.3% in cultivated rice. The possible depth of weedy rice emergence were 1.5cm, 3.0cm and 6.8cm in no-tillage, wet seeding and dry seeding paddy field, respectively. The paddy field contaminated with weedy rice was maintained as no-tillage, and then irrigated in early spring (April 15). We could induce weedy rice on the soil to emerge with irrigation, and then kill by using non-selective herbicide, paraquat. Weedy rice was controled 92.2% of total emerged by this method. After seedling establishment of cultivated rice, molinate, thiobencarb, oxadiazon, dithiopyr, butachlor were soil-applied to suppress the emergence of weedy rice seeds buried in the soil. Oxadiazon was the most effective to repress the weedy rice among soil-applied herbicides tested. The highest control value was 96.4% as the result of combination of paraquat and oxadiazon.

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

• Korean Journal of Weed Science
• /
• v.17 no.1
• /
• pp.66-70
• /
• 1997

LGC-40863(proposed common name ; pyribenzoxim), (benzophenone O-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime) is a new rice herbicide being developed by LG Chemical Ltd. The herbicide is highly selective between rice(Oryza sativa L.) and weeds including barnyardgrass (Echinochloa crus-galli(L.) P. Beauv.), and assumed to inhibit acetolactate synthase(ALS ; EC 4.1.3.18) because other structurally related herbicides inhibit the enzyme. To know inhibitory activity and the mode of inhibition of LGC-40863, $I_{50}$(concentration inhibiting ALS activity by 50%) and inhibition kinetics were investigated using ALS extracted from rice and barnyardgrass. $I_{50}$ values of LGC-40863 were 14 and 16mM in rice and barnyardgrass, respectively. In contrast to imazapyr(2-[4,5-dihydro-4-mythyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-pyridine-carboxylic acid) which showed an uncompetitive inhibition pattern, LGC-40863 was a noncompetitive inhibitor to ALS with respect to pyruvate similar to chlorsulfuron(2-chloro-N-((4-methoxy-6-methyl-l,3,5-triazin-2-yl) aminocarbonyl)benz-enesulfonamide) in both plants.

• Korean Journal of Medicinal Crop Science
• /
• v.3 no.2
• /
• pp.146-150
• /
• 1995

Weed control in the Korean ginseng(Panax ginseng C.A. Meyer) garden is more difficult than in other crops because the ginseng is a perennial crop and has to be cultivated under the artificial shading. As hand weeding is the only practical means to control weed after crop establishment, a selective herbicide would greatly simplify the control of weed in ginseng garden. In an exploratory experiment, the hervicide Fluazifop-butyl was found to be selectively safe for the Korean ginseng plants. Various rates of Fluazifop-butyl were sprayed on 2-, 3-, and 4-years old ginseng plants as a foliar spray to detect crop injury and to difine their critical concentration. No apparent injury to the ginseng plant was noticable even the doubled application rate of Fluazifop-butyl the based on recommended dosage. Neither abnormal foliar change nor any inhibition in leaf and stem growth was resulted for 2-, 3-, and 4-years old ginseng plants treated with Fluazifop-butyl tripled the recommended usage. The foliar treatments of Fluazifop-butyl did not influence the photosynthesis ability but inhibited the respiration of the ginseng leaf.

• Journal of Plant Biotechnology
• /
• v.34 no.4
• /
• pp.375-380
• /
• 2007

This study was conducted to develop herbicide-resistance domestic maize plants by introducing the CP4 5-enol-pyruvylshikimate-3-phosphate synthase (CP4 EPSPS) gene using Agrobacterium tumefaciens-mediated immature embryo transformation. Immature embryos of five genotypes (HW1, KL103, HW3, HW4, HW7) were co-cultivated with strains Agrobacterium tumefaciens (strain C58C1) containing the binary vector (pCAMBIA2300) carrying Ubiquitin promoter-CP4 EPSPS gene and Cauliflower mosaic virus 35S (CaMV35S) promoter-nptll gene conferring resistance to paromomycin as a selective agent. The presence and expression of CP4 EPSPS transgene were confirmed by PCR, RT-PCR and Northern blot analysis, respectively. Also, the resistance to glyphosate in the transgenic maize ($T_1$) was analyzed by shikimate accumulation assay. The frequency (%) of paromomycin-resistance callus was 0.37, 0.03, 2.20, 2.37, and 0.81% in pure lines HW1, KL103, HW3, HW4 and HW7, respectively. EPSP transgene sequences were amplified in putative transgenic plants that regenerated from paromomycin-resistance calli of two inbred lines (HW3, HW4). Of them, RT-PCR and Northern blot analyses revealed that the transgene was only expressed in two transgenic events (M266, M104) of HW4 inbred line, and a mild glyphosate resistance of transgenic event (M266) was confirmed by the lower shikimate accumulation in leaf segments. These results demonstrate that transgenic maize with herbicide-resistance traits in Korean genotype can be genetically obtained.

• The Korean Journal of Pesticide Science
• /
• v.4 no.3
• /
• pp.34-39
• /
• 2000

A new fifteen 2,3-dihydro-2-ethyl-2,4,6,7-tetramethylbenzofuran-5-yl substituents in 5-benzofuryl-2-[1-(alkoxyimino)alkyl]-3-hydroxycyclohex-2-en-1-one derivatives as substrate were synthesized and their herbicidal activities against rice plant (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli) with post emergence were measured under submerged conditions. The $R_{1}$=methyl substituents, $1{\sim}8$ showed the higher herbicidal activity to the rice plant and barnyard grass. The structure-activity relationships (SARs) on tile herbicidal activity of $R_{1}$ and $OR_{2}$ groups on the azomethine bond in substrates were analysized. From tile results of dicussed SAR, the herbicide activities against rice plant would depend largely on the steric factor, Whereas, in case of barnyard grass, the activities were governed by the hydrophobicity factor. The conditions of selective herbicide activity between the two plant species are assumed that the substrates should nave optimal hydrophobicity ( $(logP)_{opt.}=6.0$), a $R_{1}$ groups of small and a long $OR_{2}$ groups.

• Horticultural Science & Technology
• /
• v.19 no.1
• /
• pp.17-21
• /
• 2001

To develop a selection system for regenerating plants from transformed tissues, effects of four antibiotics (kanamycin, hygromycin, carbenicillin, cefotaxime) and herbicide (phosphinotricin) on shoot regeneration from cotyledon and hypocotyl explants of Chinese cabbage (Brassica campestris L. ssp. pekinensis) were studied. For cotyledon, shoot induction was not significantly affected by kanamycin at $1mg{\cdot}L^{-1}$, but the number of shoots formed was significantly reduced at $2mg{\cdot}L^{-1}$, and no shoots were regenerated from any explants at $6mg{\cdot}L^{-1}$ or higher. Hypocotyl explants showed similar result as cotyledon. Kanamycin at $7mg{\cdot}L^{-1}$ may be adequate for selecting Chinese cabbage transformants. Hygromycin at $4mg{\cdot}L^{-1}$ or higher completely inhibited the growth and shoot regeneration of Chinese cabbage explants. Therefore, resistance gene to hygromycin may also be used as a selective marker for Chinese cabbage transformation. Carbenicillin and cefotaxime, the cephalosporin type of antibiotics, had little effect on shoot regeneration of Chinese cabbage explants. Since carbenicillin and cefotaxime have low toxicity to Chinese cabbage, they are suitable for use in tissue culture to eliminate Agrobacterium in transformation experiments after co-cultivation. Shoot regeneration from cotyledon and hypocotyl explants was significantly reduced in presence of $1mg{\cdot}L^{-1}$ phosphinotricin (PPT) and completely inhibited by $2mg{\cdot}L^{-1}$ or higher. PPT, same as antibiotics, may also be used to select transformed cells. Since Chinese cabbage is known to be recalcitrant to in vitro shoot regeneration compared to other Brassica species, even though lower levels of selectable markers result in more transformants but simultaneously allow more untransformed escapes to develop, lower levels of antibiotics and herbicides could be successfully used as a selectable marker to reduce selection pressure.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.14 no.2
• /
• pp.144-150
• /
• 2016

Purpose: Glyphosate is a widely used non-selective herbicide. Previous studies have shown that glyphosate has genotoxicity, and that even low-doses of glyphosate can cause DNA damage. Melatonin is a hormone produced and secreted by the pineal gland that is known to be a potent anti-carcinogen, anti-oxidant, and genetic protector. This study was conducted to investigate the genoprotective effect of melatonin against glyphosate in human blood lymphocytes. Methods: Human peripheral blood was obtained from 15 young, healthy volunteers and cultured under four different toxicologic conditions. The four groups consisted of a control group, glyphosate only group (300 ng/mL), glyphosate with low level of melatonin group ($50{\mu}M$), and glyphosate with high level of melatonin group ($200{\mu}M$). The mean Sister Chromatid Exchange (SCE) frequency of each group was then analyzed. Results: Glyphosate exposed groups had a higher mean SCE frequency ($10.33{\pm}2.50$) than the control group ($6.78{\pm}2.31$, p<0.001). Interestingly, the group that received a low-level of melatonin had a lower mean SCE frequency ($8.67{\pm}2.58$) than the glyphosate-only group, while the group that received a high level of melatonin had a much lower mean SCE frequency ($8.06{\pm}2.50$) than the glyphosate-only group. There was statistical significance. Conclusion: Melatonin exerted a potent gene protective effect against the genotoxicity of glyphosate on human blood lymphocytes in a dose-dependent fashion.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.14 no.2
• /
• pp.78-82
• /
• 2016

Purpose: Green tea is known as a potent anti-oxidant, anti-carcinogen, and genetic protector. Glyphosate (N-phosphonomethyl glycine) is a widely used non-selective herbicide that causes DNA damage. The present study was conducted to investigate the protective effects of green tea in human blood lymphocytes exposed to glyphosate using the Sister Chromatid Exchange (SCE) frequency method. Methods: Peripheral blood was obtained from 10 volunteers and cultured through four different conditions. Four groups were divided into control, glyphosate only (300 ng/mL), glyphosate and low ($20{\mu}m$) concentrations of epigallocatechin gallate (EGCG) and glyphosate and high ($100{\mu}m$) concentrations of EGCG. Results: The glyphosate exposed groups had a higher mean SCE frequency ($10.33{\pm}2.50$) than the control group ($6.38{\pm}2.28$, p<0.001). The low concentrations of EGCG groups had a lower mean SCE frequency ($9.91{\pm}1.93$) than the glyphosate-only group, although this difference was not significant (p=0.219). However, the high concentration group ($9.49{\pm}1.85$) had a significantly lower SCE frequency than the glyphosate-only group (p=0.001). Conclusion: EGCG has a gene protective effect in human lymphocytes exposed to the genotoxicity of glyphosate in the case of high concentrations.

• Korean Journal of Medicinal Crop Science
• /
• v.12 no.5
• /
• pp.360-365
• /
• 2004

Rehmannia glutinosa shows a high level of resistance to the non-selective herbicide paraquat. To characterize the antioxidant enzyme system of R. glutinosa, we comparatively examined the responses of antioxidant enzymes to UV, wounding and a general elicitor yeast extract in R. glutinosa and soybean. The levels of enzyme activities of the two plant species were drastically different between those per fresh weight (general activity) and per protein (specific activity) bases. The general activities of superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and glutathione reductase (GR) were lower, but that of ascorbate peroxidase (APX) was higher in R. glutinosa than in soybean. The specific activities of the enzymes, however, were about two- to seven-fold higher in R. glutinosa than in soybean, except that of CAT, which was about 12-fold higher in soybean. The general and specific enzyme activities of R. glutinosa relative to those of soybean showed a consistent increase in responses to the stresses only in SOD. The specific activities of SOD and APX were higher in R. glutinosa in all stress treatments. The results might suggest a relatively higher contribution of SOD and APX to the stress tolerance.