• Weed & Turfgrass Science
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• v.2 no.3
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• pp.230-235
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• 2013

Amaranths (Amaranthus sp.), an endemic American crop, are now grown widely across the world. This study used 14 simple sequence repeat (SSR) markers to analyze the genetic diversity of 74 amaranth accessions from the United States, with eight accessions from Australia as controls. One hundred twenty-two alleles, averaging eight alleles per locus, were observed. The average major allele frequency, expected heterozygosity, and polymorphism information content (PIC) were 0.44, 0.69, and 0.65, respectively. The structure analysis based on genetic distance classified 77 accessions (94%) into three clusters, while five accessions (6%) were admixtures. Among the three clusters, Cluster 3 had the highest allele number and PIC values, while Cluster 2 had the lowest. The lowest FST was between Clusters 1 and 3, indicating that these two clusters have higher gene flow between them compared to the others. This finding was reasonable because Cluster 2 included most of the Australian accessions. These results indicated satisfactory genetic diversity among U.S. amaranths. These findings can be used to design effective breeding programs involving different plant characteristics.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.164-168
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• 1985

In order to enhance herbicidal efficacy of amide and diazine herbicides, synergistic effects of pretilachlor and pyrazoxyfene or butachlor and pyrazolate on control of Cyperus serotinus were determined by isobole method. Interaction indices(I) between pretilachlor and pyrazoxyfene treated at 0 and 3rd leaf stage were 2.64 and 2.07 and hence showed synergistic effect for control of Cyperus serotinus. The points indicated Imax between pretilachlor and pyrazoxyfene were 0.7:1.3 g ai/a and 9.0:20.5 g ai/a at 0 and 3rd leaf stage, respectively. Combination of butachlor and pyrazolate showed synergistic effect(1=1.57) on control of Cyperus serorinus and point indicated Imax was 48.0:20.9 g ai/a.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.152-159
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• 2011

The effects of simulated acid rain (SAR) on fatty acid composition and biochemical defense responses of plant was investigated. Garden balsam (Impatiens balsamina L.) was exposed to four pH levels (5.6, 4.0, 3.0, 2.0) of SAR and placed in the growth chambers for 2 weeks. SAR drastically inhibited chlorophyll content of garden balsam. The level of $H_2O_2$ was significantly increased by SAR. As pH levels decreased from 5.6 to 2.0, the ratio of unsaturated to saturated fatty acids of garden balsam was increased. Changes of three major polyamines (putrescine, spermidine and spermine) of garden balsam leaves were observed. All of the polyamine contents were increased with SAR. Catalase activities of the plant affected by SAR were increased as the pH decreased. The results indicate that the application of SAR generates oxidative stresses from the garden balsam and retards the plant growth significantly. A biochemical protect mechanism might be activated to neutralize the oxidative stresses generated through SAR.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.179-185
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• 1987

Laboratory studies were conducted to evaluate safening effect of CGA 123'407 (4,6-dichloro-2-phenyl-pyrimidine) against pretilachlor, butachlor, and benthiocarb in rice plants. Butachlor and benthiocarb at 50 ppm or higher concentrations significantly inhibited rice growth and pretilachlor gradually inhibited growth of rice plants with increase in concentration starting from 0.5 ppm. CGA 123'407 at 0.1 ppm or higher concentrations was effective in reducing injury of rice plants when butachlor and benthiocarb were applied at rate of 10 ppm. Rice injury from pretilachlor at 10 ppm was also reduced by addition of CGA 123'407 at 0.25 ppm or higher concentrations Herbicidal activity of pretilachlor, butachlor, and benthiocarb was not affected by mixture treatments of CGA 123'407.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.74.2-74.2
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• 2010

We present a multi-wavelength study of a supercluster in the NEP region at z=0.087, using AKARI (Infrared space telescope) NEP-Wide (5.8 deg2) survey which has obtained an unique IR imaging dataset with contiguous wavelength coverage from 2 to $24{\mu}m$, overcoming the Spitzer limitation of imaging capability at $10-20{\mu}m$. The NEP-Wide survey is also covered in other wavelength such as X-ray, Radio, GALEX UV in the archive, optical (BRI from Maidanak 1.5m and CFHT's MegaPrime), and NIR imaging data (JH from KPNO 2.1m), with nearly 1900 optical spectra, mostly obtained by our group using MMT/Hectospec and WIYN/Hydra. Armed with the multiwavelength datasets, we investigate the connection between IR properties of galaxies and their environments as a tool to understand the evolution of galaxies in a supercluster environment. Specific attention will be given to MIR emission which can trace star formation activities and passive phases right after post-starbursts, and its relation to other wavelength data.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.254-259
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• 2013

The mechanisms of resistance to oxyfluorfen (OF) and paraquat (PQ) were investigated in rice plants. Examination of the concentration dependence of oxyfluorfen- or paraquat-induced increase in conductivity showed that conductivities in the OF- and PQ-treated leaf squares were increased with 0.1 ${\mu}M$ oxyfluorfen and 0.01 ${\mu}M$ paraquat and further increased with higher concentrations. The levels of conductivity were approximately 10-times higher in the PQ-treated plants than in the OF-treated plants, indicating that the PQ-treated plants suffered more severe photodynamic damage than the OF-treated plants. The photooxidative stress caused by foliar application of either 50 ${\mu}M$ oxyfluorfen or 100 ${\mu}M$ paraquat increased the enzyme activities of ascorbate peroxidase and peroxidase 1 day after the herbicide treatments and then further increased their enzyme activities 2 days after the treatments. The activities of catalase began to increase 2 days after the oxyfluorfen and paraquat treatments. These antioxidant enzymes appear to play an essential part of defense mechanisms against oxyfluorfen and paraquat. Our results demonstrate that paraquat caused more severe oxidative stress, as indicated by a greater change in conductivity, thereby resulting in greater increases in antioxidant responses in plants, compared with those of oxyfluorfen.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.247-248
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• 1996

In order to study the X-ray radiations from solar type strong interacting binary stars, we have collected X-ray data of 44i Bootis (P=0.2678 days, SP=G2+G2) from the EXOSAT data archive. Preliminarly analysis of a part of these data has been already reported by Vilhu & Heise (1986). In this paper, however, we present a more complete light curve in LE region than the previous work, and some unpublished X-ray light curves and spectrums. Using these new materials a new attempt to find the physical explanation about. some observational characteristic figures in the X-ray light curves and spectrums has been made.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.154-159
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• 1995

Water extracts from Polygonum aviculare and Salix koreansis markedly inhibited the germination of lettuce and rice seeds, indicating the presence of biologically active substances. The biochemical substances such as salicylic and+vanillic acid, tannic acid + gallic acid, p-coumaric acid, p-cressol, sinapic acid and catechol etc. belonging to phenolic compounds were detected in the cultured cells, suggesting that the secondary metabolites can be synthesized in plant cell and tissue culture. In addition, fatty acid like linolenic acid and organic acid such as oxalic acid were presented in the highest amount, 3.7 mg/g and 14.288 mg/g, respectively, which seem to be related to exhibiting phytotoxicity of P. aviculare. Petroleum ether extract exhibited another potential relating to inhibitory effect which needs further investigation. Calli from two plant sources were easily introduced by uses of 1.0 mg/l of 2.4-D and 0.1 to 0.2 mg/l of BAP in MS basal medium which can be implemented for a large scale production through cell culture.

• Weed & Turfgrass Science
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• v.6 no.4
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• pp.313-321
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• 2017

Wetting agent is designed to reduce the surface tension of the liquid and spread more easily across or penetrate into the soil against water repellency. The effect of wetting agent to seed germination is not clear. Using germination enhancer is one of the methods to increase the germination speed of turfgrass seeds and to shorten establishment period. The objective of the study was to evaluate germination enhancer and wetting agent for quick establishment of various Kentucky bluegrass cultivars. The germination enhancer was used at two levels of 0.3 and $0.6ml\;kg^{-1}$ as low and high, respectively. Two levels of wetting agent were of 0.46, and $0.92ml\;m^{-2}$ as low and high, respectively. Germination enhancer has no synergistic effect with wetting agent. When quick establishment is required, selection of cultivar would be more effective instead of using germination enhancer and wetting agent. Among Kentucky bluegrass cultivars, 'Award' had the greatest turfgrass coverage for establishment and the greatest turfgrass color and quality based on the result of the study. When quick establishment is required, selection of cultivar would be more effective instead of using germination enhancer and wetting agent.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.187-193
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• 1985

The experiment was carried out to evaluated the interaction between perfluidone(2-methyl-4-phenylsulphonyltrifluoromethylsulphoanilide) and bifenox(2,4-dichlorophenyl-3-methoxycarbonyl-4-nitrophenylether). A synergistic effect was found between perfluidone and bifenox. The highest synergistic effect on Echinochloa crus-galli (L.). Beauv. was obtained when 10 g a.i./10a of perfluidone was combined with 24.9 g a.i./10a of bifenox. However, bifenox should be increased to 33.3, g a.i./10a to obtain the highest synergistic effect when applied to Cyperus serotinus Rottb. at 1.0-1.5 leaf stage. Sagittaria pygmaea Miq. at 0.5-1.0sleaf stage was completely controlled by the lowest combination rate employed.