• Journal of Applied Biological Chemistry
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• v.42 no.1
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• pp.45-47
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• 1999

Two phytotoxic compounds were isolated from a culture of Exserohilum monoceras Inu-1, a fungal pathogen of Barnyard grass. The structure was determined by spectroscopic analyses including 2D NMR experiments. During the isolation procedure, the toxic components were monitored by the assay using Italian ryegrass (Lolium multiflorum Lam.), a host plant of the pathogen. The compounds inhibited the root growth of the host plant seedlings at a level of 100 ppm. While no substantial inhibition was observed even at 300 ppm in non-host plant seedlings such as lettuce and tomato.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.388-394
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• 2001

Quantitative Structure-Activity Relationship (QSAR) have been established of 57 fluorovinyloxyacetamides compounds to correlate and predict EC50 values. Genetic algorithm (GA) and multiple linear regression analysis were used to select the descriptors and to generate the equations that relate the structural features to the biological activities. This equation consists of three descriptors calculated from the molecular structures with molecular mechanics and quantum-chemical methods. The results of MLR and GA show that dipole moment of z-axis, radius of gyration and logP play an important role in growth inhibition of barnyard grass.

• Applied Biological Chemistry
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• v.48 no.3
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• pp.252-257
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• 2005

Three-dimensional quantitative structure-activity relationships (3D-QSARs) for the herbicidal activities against pre-emergence barnyard grass (Echinochloa crus-galli) by new 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenylpropion amide derivatives were studied quantitatively using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methodologies. The best CoMFA model (AI-2) and CoMSIA model (AII-4) were derived from an atom based fit alignment and a combination of CoMFA fields. The herbicidal activities from CoMFA and CoMSIA contour maps showed that the activity will be able to be increased according to the substituents variation on the N-phenyl ring.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.219-222
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• 2008

In the search for third generation herbicidal cyclic imide derivatives, the average values of herbicidal activity ($pI_{50}$) in vivo (pre-emergence) of 40 new peroxidizing herbicides, 1-(4-chloro-2-fluoro-5-propargyloxyphenyl)thiourea derivatives (1-40) against rice plant (Orysa sativa) and barnyard grass (Echinochlor crus-galli) were studied. The molecular similarity between protoporphyrinogen IX (protogen) as the substrate of protox enzyme and Urea derivatives (1-40) was discussed quantitatively. The diallyl (20) and 3-nitro substituent (33) showed the selective herbicidal activity against barnyard grass. Allyl substituent (8) and their molecular similarity in dice (S=0.81) showed the highest levels of herbicidal activity ($pI_{50}$=4.71). Also, similarity indices (S) and superimposed volume (C) of protogen and aryl-substituents (21-40) showed good correlation.

• Environmental Engineering Research
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• v.12 no.2
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• pp.37-45
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• 2007

Phytoremediation has been used effectively for the biodegradation of oil-based contaminants, including diesel, by the stimulation of soil microbes near plant roots (rhizosphere). However, the technique has rarely been assessed for itsinfluence on soil microbial properties such as population, community structure, and diversity. In this study, the removal efficiency and characteristics of rhizobacteria for phytoremediation of diesel-contaminated soils were assessed using barnyard grass (Echinochloa crusgalli). The concentration of spiked diesel for treatments was around $6000\;mg\;kg^{-1}$. Diesel removal efficiencies reached 100% in rhizosphere soils, 76% in planted bulk soils, and 62% in unplanted bulk soils after 3weeks stabilization and 2 months growth(control, no microbial activity: 32%). The highest populations of culturable soil bacteria ($5.89{\times}10^8$ per g soil) and culturable hydrocarbon-degraders($5.65{\times}10^6$ per g soil) were found in diesel-contaminated rhizosphere soil, also yielding the highest microbial dehydrogenase. This suggests that the populations of soil bacteria, including hydrocarbon-degraders, were significantly increased by a synergistic rhizosphere + diesel effect. The diesel treatment alone resulted in negative population growth. In addition, we investigated the bacterial community structures of each soil sample based on DGGE (Denaturing Gel Gradient Electrophoresis) band patterns. Bacterial community structure was most influenced by the presence of diesel contamination (76.92% dissimilarity to the control) and by a diesel + rhizosphere treatment (65.62% dissimilarity), and least influenced by the rhizosphere treatment alone (48.15% dissimilarity). Based on the number of distinct DGGE bands, the bacterial diversity decreased with diesel treatment, but kept constant in the rhizosphere treatment. The rhizosphere thus positively influenced bacterial population density in diesel-contaminated soil, resulting in high removal efficiency of diesel.

• Applied Biological Chemistry
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• v.39 no.2
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• pp.153-158
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• 1996

During the screening of herbicidal substances from microbial secondary metabolites using photoautotrophic cells, a strain of ME-13 with strong herbicidal activity was isolated from soil. Based on the taxonomic studies, the strain was identified as Streptomyces. Two active compounds were purified from the culture broth through the column chromatographies using active charcoal, silica gel, MCI gel, and ODS HPLC. The compounds were identified as AB3217-A and B, respectively, related to anisomycin by spectroscopic methods. AB3217-A and B completely suppressed the germination of radish and barnyard grass at 25 ppm. In comparison to anisomycin, they showed the 6 times higher inhibitory activities against the growth of shoot and root of radish and barnyard grass with EC5O of around 6 ppm.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.129-135
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• 2013

This study was conducted to investigate the soil characteristics of newly reclaimed tidal land and the effect of green manure crops on soil properties. Summer green manure crops such as sesbania (Sesbania grandiflora), barnyard grass (Echinochloa spp.) and sorghum${\times}$sudangrass hybrid (Sorghum bicolor L.) were cultivated at Hwaong, Ewon, Saemangeum and Yongsangang area. Soil pH of reclaimed tidal land was relatively high, but organic matter and available phosphorus contents were lower compared to the optimum range for common upland crops. Soil nutrient contents were unbalanced for upland crop growth. Yield of green manure crops had a wide spatial variation. Nitrogen content in green manure crops was the greater in Sesbania and it was estimated that major nutrient ($N-P_2O_5-K_2O$) supply amount were 150-40-370, 220-50-170 and 140-50-250 $kg\;ha^{-1}$ from sorghum${\times}$sudangrass hybrid, sesbania and barnyard grass, respectively. Based on these results, desalination is required to grow the upland crops at newly reclaimed tidal lands and management practices are necessary to reduce the salt damage by resalinization during the growing seasons. To improve the productivity and increase the nutrient utilization rate, soil physicochemical properties need to be improved to the level for upland crops by application of organic matter and fertilizer.

• Applied Biological Chemistry
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• v.47 no.4
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• pp.414-421
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• 2004

3D QSAR studies for protox inhibition activities against root and shoot of the rice plant (Orysa sativa L.) and barnyardgrass (Echinochloa crus-galli) by a series of new 1-(5-methyl-3-phenylisoxazolin-5-yl)methoxy-2-chloro-4-fluorobenzene derivatives were conducted based on the results (Sung, N. D. et al.'s, (2004) J. Korean Soc. Appl. Biol. Chem. 47(3), 351-356) using comparative molecular similarity indices analysis (CoMSIA) methodology. Four CoMSIA models, without hydrogen bond donor field for the protox inhibition activities against root and shoot of the two plants, were derived from the combination of several fields using steric field, hydrophobic field, hydrogen bond acceptor field, LUMO molecular orbital field, dipole moment (DM) and molar refractivity (MR) as additional descriptors. The predictabilities and fitness of CoMSIA models for protox inhibition activities against barnyard-grass were higher than that of rice plant. The statistical results of these models showed the best predictability of the protox inhibition activities against barnyard-grass based on the cross-validated value $r^2\;_{cv}\;(q^2=0.635{\sim}0.924)$, non cross-validated, conventional coefficient $r^2\;_{ncv.}$ value $(r^2=0.928{\sim}0.977)$ and PRESS value $(0.255{\sim}0.273)$. The protox inhibition activities exhibited a strong correlation with the steric $(5.4{\sim}15.7%)$ and hydrophobic $(68.0{\sim}84.3%)$ factors of the molecules. Particularly, the CoMSIA models indicated that the groups of increasing steric bulk at ortho-position on the C-phenyl ring will enhance the protox inhibition activities against barnyard-grass and subsequently increase the selectivity.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.172-178
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• 2009

Relation between spatial variation of soil salinity and emergence of five upland crops such as sudan grass, sesbania, barnyard grass, corn and soybean was studied in the three reclaimed lands of Korea during two years from 2007 to 2008. Although soil salinity is vary high at seeding season, desalting treatment by three days-flooding before seeding, reach at favorable level lower than $6dS\;m^{-1}$ of soil salinity for emergence of soiling and forage crops and then plant number emerged(No. $m^{-2}$) was 55~149 for sudan grass, 118~266 for barnyard grass, 46~115 for sesbania, 3~11 for corn and 6~19 for soybean in 2007. However plant number emerged under no desalting treatment varies place by place because of soil salinity difference in 2008. Plant number emerged after seeding according to soil salinity was well expressed as logarithmic function, and sharply decrease with increase of soil salinity. It is accordingly concluded that desalting treatment of flooding before seeding of upland crops is essential for good emergence in the newly reclaimed land from tidal flat.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.179-186
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• 2009

Relation between soil salinity and forage yield of five upland crops such as sudan grass, sesbania, barnyard grass, corn and soybean was studied in the three reclaimed lands of Korea during two years from 2007 to 2008. Although plant number emerged was obtained satisfactory by desalting treatment, further growth of crops was sharply affected by re-salting process according to soil drying. Soil salinity varied place by place and changed constantly, crop growth was differently responded to soil salinity according to the specific conditions of the reclaimed lands. In the Iweon reclaimed land with higher soil water conductivity and sandy soil texture, crop growth and yield sharply decrease with increase of soil salinity. Relation between soil salinity and crop growth and yield was well expressed as logarithmic function. Surface soil EC to reach at 50% of growth reduction to the tallest height of crops was $5dS\;m^{-1}$ for soybean, $6dS\;m^{-1}$ for corn and $7dS\;m^{-1}$ for sudan grass, sesbania, and barnyard grass by logarithmic function. In the Hwaong and Yeongsangang reclaimed lands with low soil conductivity and finer soil texture, plant growth response to salt stress was statistically vague by mixing of harmful influence from flooding and wet injury. However, it is observed that crop growth and yield on the place of lower salinity was better than crop growth on the place of higher salinity. It is accordingly concluded that flooding control during summer rainy season is vary important as well as desalting process for good growth of soiling and forage crops in the newly reclaimed land from tidal flat.