• The Korean Journal of Ecology
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• v.19 no.1
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• pp.71-80
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• 1996

The effects of simulated acid rain on the growth and interspecific competition of Echinochloa crus-galli and Digitaria sanguinalis were studied. Changes of growth in height and dry weight were examined and competition between the two species was investigated using the experimental model proposed by de Wit (1960). The experiments were carried out in the greenhouse, and test plants were germinated and grown for 4 weeks and then sprayed with simulated acid rain of pH 5.6, 4.2 and 2.8 for another 8 weeks. In de Wit replacement experiments, the variation of density and the treatment of simulated acid rain showed little effect on the interspecific competition between E. Crus-galli and D.sanguinalis. The ratio diagram, another method to reveal the interrelations between two competing species, always showed the predominance of E. crus-galli in competition, regardless of density and pH. The interspecific competition of the two species, represented by relative yield total (RYT), revealed that intraspecific competition was stronger than interspecific competition in both species.The treatment of simulated acid rain showed little effect on the growth of E. Crus-galli and D. sanguinalis. Height growth of both species did not differ from that of control (pH 5.6), but root/shoot ratio increased with the decrease in pH of simulated acid rain. Growth of tatal dry weight of E. crus-galli and D. sanguinalis was not influenced by the change of pH, except that D.sanguinalis showed a decrease in the total dry weight at pH 2.8 along with a visible sign of white spots on leaves. Physical environmental conditions can exert an effect on the interrelationships between the two species, but this experiment did not show the reversion of competition, and showed that E.crus-gilli was competitively dominant under any environmental conditions given in this study.

• Journal of Environmental Science International
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• v.12 no.12
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• pp.1207-1213
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• 2003

Osancheon creek is located in the southwest of the middle area in Korea. Weed community around the Osancheon creek, where various disturbances exert a bad influence directly on its community by human work or nature, was surveyed phytosocialogically. Our surveys have been accomplished from June, 2003 to September, 2003. Weed communities formed around the Osancheon creek were divided into several patterns and analysed. They have been divided into 8 communities. Community A: Humulus japonica community, B: Phragmites communiscommunity, C: Persicaria thunbergii community, D: Zi=ania latifolia community, E: Miscanthus saccharilflorus community, F: Echinochica crusgalli community, G: Typha orientalis community, H: Sataria viridis community. The flora surveyed in these communities was constituted of 19 families, 36 genera, 4 varieties, and 40 species. Wild plants such as Artemisia princeps var. orientalis Erigeron annuus, Bidens frondosa, Aeschynomene indica and Oenothera odorata were mostly light loving plants and higher resistant plants against the disturbance. Our result from the ranking all surveyed areas by the Bray-Curtis ordination method was very similar to the results from phytosocialogical table work.

• Korean Journal of Environment and Ecology
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• v.24 no.3
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• pp.264-278
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• 2010

This study was carried out to describe the basic materials of the flora and vegetation for the conservation and management of the Dokdo ecosystem. The vegetation types were investigated by physionomy. 53 taxa of vascular plants were found, including 29 families, 48 genera, 49 species, 1subspecies, and 3 varieties. Among the investigated 53 taxa, it was recorded as follows: 2 Korean endemic plants included Sedum kamtschaticum var. takesimense M.Park and Campanula takesimana Nakai and 6 naturalized plants included Brassica juncea (L.) Czern., Sonchus oleraceus L., Bromus catharticus Vahl, Lepidium virginicumL., Chenopodium album L., and Ipomoea purpurea Roth. In particular, common morning glory (Ipomoea purpurea Roth) was reported for the first time in this survey of Dokdo. Based on physionomy, the main plant communities of Dokdo Island were Aster spathulifolius-Sedum oryzifolium community, Aster spathulifolius-Artemisia Japonica subsp. littoricola community, Fallopia sachalinensis-Cyrtomium falcatum community, Echinochloa crusgalli community, Echinochloa crusgalli var. oryzicola community. The debates have been continuing about a mis-identification of plants. To avoid this debate and manage naturalized and cultivated plants, taxonomist surveys and continual monitoring for the Island are required.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.413-420
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• 2008

The phytosociological study was carried out to investigate the structural characteristics of paddy levee vegetation in South Korea. The vegetation data of total 59 releves were analyzed by the Zurich-Montpellier school's method. 6 syntaxa (3 associations and 3 communities) of paddy levee were recognized : Echinochlo-Digitaretum ciliaris ass. nov. hoc., Artemisia princeps-Erigeron annus community, Imperata cylindrica v. koenigii community, Glycine soja-Humulus scandens community, Miscantheum sinensis f. purpurascens ass. nov. hoc,, Polygonetum thunbergii Lohm. et Miyawaki 1962. Detrended correspondence analysis(DCA) showed that Artemisia princeps-Erigeron annus community and Imperata cylindrica v. koenigii community were positively correlated with soil hardness. Polygonetum thunbergii Lohm. et association and Miscantheum sinensis f. purpurascens ass. nov. hoc. was intimately correlated with high soil total nitrogen.

• Weed & Turfgrass Science
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• v.5 no.2
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• pp.60-64
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• 2016

Investigation on weed flora in Lycium chinense upland fields was conducted to understand the current status of weed flora and establish the control measures. Investigation was conducted twice, May and June on 2015. From this investigation, 91 species of 30 families including 27 exotics were identified into 36 species of annuals, 28 species of biennials and 27 species of perennials. Dominance was the highest with Portulaca loeracea followed by Digitaria ciliaris, Stellaria media, Oxalis corniculata, Acalypha australis, Chenopodium album, Cyperus iria etc. in order. Chenopodium album was the highest in importance analysis and the followings were in order of Conyza canadensis, Conyza bonariensis, Senecio vulgaris, Amaranthus lividus, Sonchus asper etc.

• Korean Journal of Environment and Ecology
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• v.18 no.2
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• pp.221-230
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• 2004

Flora of the Dokdo Islet, where located south-east from Ulnung Island, off the east coast of the Korean peninsula, recorded as 59 taxa; 29 families, 50 genus, 48 species, 1 sub-species, 9 varieties and 1 form. Dong-do (East islet) of Dokdo Islet, naturalized plants such as Brassica campestris subsp. napus var. nipp-oleitera and Rumex crispus are widely ranged over the islet. The naturalizedplants affects the native species and their habitats of Artemisia japonica var. macrocephala, Echinochloa crus-galli, Sedum oryzifolium, Arabis stelleri var. japonica and Sedum kamtschaticum var takesimense in the islet. The trail in Seo-do (West islet) is heavily threatened by over-all weathering processes on the rock. The native woody species in the islet are Euonymous japonicus and Lonicera insularis, and the species such as Pinus thunbergii and Hibiscus syriacus are planted in the recent past under the IRP (Islet Restoration Program) by NGO. The Specific Plants, which is designated and categorized by the Ministry of Environment, Korea, such as Lilium lancifolium, Lysimachia mauritiana and Reynoutria sachalinensis are ranged. The ecosystem of Dokdo islet is seriously threatened by invadedplant species and building works for garrison and relevant facilities. The over-all long- and short-term strategies, based on interdisciplinary and integrated approaches for habitat restoration is needed.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.9-14
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• 1988

Three varieties of Echinochloa crus-galli (L.) Beauv. and five collections different in gross morphology from the E. crus-galli species were obtained in a lowland rice field located in Jukjeol-Ri, Soyang-Myeon, Wanju-Kun, Jeonbug to compare the ecological and physiological characteristics. There were great variations in seed dormancy, relative growth rates, days required to panicle emergence and panicle morphology among the collections. On the basis of the cluster analysis using the different characteristics, the collections were divided into three groups; E. crus-galli var. frumentaceae and its two ecotypcs, E. crus-galli var. echinata and its two ecotypes, and E crus-galli var. crus-galli and its one ecotype. There were differential responses in percent germination and post-germination growth of the collections to butachlor (2-chloro-2', 6'-diethyl-N-butoxymethyl acetanilide).

• Korean Journal of Weed Science
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• v.31 no.4
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• pp.330-339
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• 2011

This study was conducted to determine the herbicidal activity of herbicidal substances and identify them in bulbs of Lycoris flavescens. Methanol extract was purified by a series of chromatographic techniques including silica gel column chromatography, preparative TLC, and HPLC. The final HPLC gave two active fractions and two herbicidal substances were obtained. By GC/MS analysis, one was identified as galanthine (galanthan-1-ol) and the other was identified as montanine ($O^2$-methyl pancracine), an isoquinoline alkaloid. Montanine showed nearly 100% of growth inhibition on the shoot and root of barnyardgrass (Echinochloa crusgalli) seedlings at $20{\mu}g\;mL^{-1}$ as compared with the control. Meanwhile, methanol extract of L. flavescens bulbs showed only about 3.1% and 8.3% of growth inhibition on the shoot and root of rice cultivar, Hwayeongbyeo seedlings at $1,000{\mu}g\;mL^{-1}$ as compared with the control, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.40-44
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• 1981

This study was conducted to identify the possibility of paddy weeds served as the host plant of bacterial leaf blight, using various bacterial groups and inoculation methods. The results obtained can be summarized as follows. 1. Alopecurns spp., Setaria viridis P. Beauv., and Leersia juponica Makino were identified the most susceptible to bacterial leaf blight, similar to Milyang 23 which was used as a susceptible check variety. The others such as Digitaria adscendens Hem., Eleusine indic aGaertin., Cyperns serotinus Rottb, Cyperns difformis L. showed slight infection but most of broadleaf weeds were resistant to bacterial leaf blight. 2. Weed species showing early susceptibility maintained their susceptibility throughout the growth stages. Group I of bacterial leaf blight was the most effective to develop infection symptom to weeds. 3. Pin and scissor inoculation methods were more effective mean for infection than spray method which was used without wound.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.415-427
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• 1984

This experiment was carried out to investigate the distribution of associative nitrogen fixers, Azospirillum spp. and their nitrogenase activities measured by ARA in the rhizosphers of rice, soybean, and weed grown in the rice paddy field at ear formation stage of rice. Nitrogenase activities produced by Azospirillum spp. enriched from histophere ranged from 16 to 53 n mole/tube/hr.. High nitrogen fixing activities more than 30 n mole/tube/hr. were observed in the histophere of the Echinochloa crus-galli L., Finbristylis miliacea L., and Monochoria vaginalis var.. Nitrogen fixing activities of Azospirillum spp. obtained from single colonies which originated from the rhizoplane of rice (pot-kwang var.), Finbris tylis miliacea L., Monochoria vaginaliz var., Glycine max L. were higher over 100 n mole/tube/hr. than those histophere. Genus of Azopsirillum isoltated from roots of the Graminease (Oriza sativa L., $C_3$-plant, Echinochloa crus=galli L., $C_4$-plant, Cyperus difforuis L.. $C_4$-plant), and Aeschynomene indica L. (Leguminosae, $C_3$-plant) was identified as A. brasilense. However, both strains, A. lipoferum and A. brasilense ($nir^-$ or $nir^+$ strain) were isolated from other plant roots, Both $nir^-$ and $nir^+$ strains of A. brasilense were associated with the same host plant.