• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.11-20
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• 2012

Methanol extracts of aquatic plants were analyzed for allelopathic activities against Escherichia coli JM109 and $Microcystis$ $aeruginosa$ UTEX2385 which were compared to its 2,2-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities. The radical scavenging activities were detected from the extracts of $Persicaria$ $thunbergii$, $Persicaria$ $amphibia$, $Trapa$ $japonica$, $Myriophyllum$ $spicatum$, and $Brasenia$ $schreberi$. Also, the inhibitory activities against cyanobacteria were analyzed according to the order of $B.$ $schreberi$, $T.$ $japonica$, $P.$ $amphibia$, and $M.$ $spicatum$. Most of the extracts from aquatic plants did not show any inhibition against $E.$ $coli$ except $B.$ $schreberi$. We found a positive correlation between the antioxidental activities of methanol extract of aquatic plants and the growth inhibitory activities for cyanobacteria in terms of the DPPH radical scavenging activities ($R^2$=0.381, $P$ <0.0001). The inhibitory activities of methanol extract against $E.$ $coli$ growth was not correlated with the other activities of aquatic plants ($P$ >0.04). We suggest from this study that the allelopathic effects of aquatic plants against cyanobacteria could be screened by using the bioassay based on DPPH.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.3
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• pp.189-196
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• 1993

Allelopathic inhibition by substance(s) originated from sicklepod(Cassia tora L.) seed on germination of other plant seeds, was confirmed and used to elucidate general mechanism of allelopathy which was occurred widly in natural and/or agricultural ecosystems. The mechanism was deduced from changes in water contents, ${\alpha}$-amylase activities, protease activities, concentrations of abscisic acid and total phenolic compounds during germination of rice and radish seeds treated with water-soluble extracts of sicklepod seeds. The results obtained were summarized as follows. 1. The % germinations of radish, rice, lettuce, barley seeds were decreased by substances originated from crushed sicklepod seeds. 2. By the treatment of water-soluble extracts of sicklepod seeds, the inhibition of germination of radish seeds was occured with the sequential phenomena of increase of protease activity(synthesis), decrease of water content and increase of total phenolic compounds content. 3. In rice, the inhibition of seed germination by the water-slouble extracts of sicklepod seeds was related to increase of abscisic acid concentration and then decrease of ${\alpha}$-amylase activity(synthesis).

• The Korean Journal of Ecology
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• v.24 no.3
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• pp.137-140
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• 2001

The antifungal activity of chemical substances from Artemisia annua were examined. Antifungal activity of aqueous extracts from A. annua was higher than that of essential oils in Fusarium oxysporum, whereas that of essential oil was higher than that of aqueous extracts in Aspergillus nidulans. The GC/MS methods were employed for the analysis and identification of phytotoxic substances from A. annua. Essential oil of some components were identified including thujone, terpineol, β-pinene, cienole, 2,4-hexndienal, camphor, citronellal, (-)-menthone, (1R)-(-)myrtenol, (S)-(-)-perilla aldehyde, perilla alcohol, 4-tert-buthylaniline, eugenol, isosafrole, isoeugenol and α-humulene. These results suggest that the chemical substances from A. annua such as terphenoids seem to be responsible for the allelopathic effect.

• Korean Journal of Oriental Medicine
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• v.14 no.1
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• pp.123-128
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• 2008

Glehnia littoralis (Umbelliferae), a perennial herb distributed along the coastline of northern Pacific countries, is the medicinal plant used traditionally for treatment of various diseases. This review focuses on the various pharmacological activities of Glehnia littoralis for understanding about its traditional medicinal applications, medicinal uses in the modern society, and potentials for drug development Glehnia littoralis was reported to have anti-oxidant, anti-tumor, anti-amnesic, blood circulation-promoting, immunomodulatory, anti-microbial, and allelopathic activities. However, their mechanisms remain to be clarified. Because Glehnia littoralis has been prescribed in traditional Oriental medicine as a tonic herb, Glehnia littoralis can be better than other chemical drugs and medicines which exert the equal pharmacological activities. Although the activities of Glehnia littoralis are not specifically high-potent with unique mode of action, it may turn out that it can be beneficial to exert multiple pharmacological activities. In view of low toxicity, relative cheapness, presence in the diet, and occurrence in various herbal remedies of Glehnia littoralis, it needs to be prudent to evaluate its properties and applications further.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.2
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• pp.79-83
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• 2005

Rice and weed interference in the paddy field caused by resource competition and allelopathy. Evaluation method of active weed suppressive behavior of rice to weed was developed by eliminating light competition at soil condition. Twenty eight days old rice seedlings (6-7 leaf stage) which was grown at saturated, no drainage pot were clipped above $3\~4cm$ from the soil surface. Weeds seeded around clipped rice stem, named ratoon seeding screening method, showed varietal suppressive difference to Echinochloa crus-galli, Echinochloa crusgalli var. praticola and Monochoria vaginalis. Potential allelopathic rice varieties, Sathi, AC1423 and PI312777 showed better suppressive activity to weed seedling growth than Nonganbyeo and Keumobyeo. Weed suppression of one plant of rice cultivars could be evaluated by the cell size of $2.5\times2.5cm$ at rice clipping of seedling 29 days after rice seeding.

• Korean Journal of Weed Science
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• v.12 no.1
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• pp.52-60
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• 1992

There was no significant difference in the final germination percentages(Experiment 1-3) as affected by sunflower root exudates between the control and the treated for the test species. In general(Experiment 1), however, germination onset was delayed the treated bottles. Germination rate was, also, reduced for both radish(Raphanus sativus L.) and rice(Oryza sativa L.). Therefore, the germination index was low in the treated bottles but germination gradually increased with time in the greated bottles in all test species so that the final germination percentages were similar between treatments. The root exudates of sunflower had significant inhibitory effects(Experiment 1-3) on the lengths of the shoots and roots of all the test species. Fresh weight was also significantly reduced in all test species. Sunflower seedlings(Experiment 3) in the treated(with the XAD-4 resin column) were larger and healthier than those in the control (without XAD-4 resin column) because of the removal of allelochemicals. The fresh weight of sunflower seedlings was markedly inhibited by sunflower root exudates. These mean that sunflower probably is an autotoxic crop.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.1-6
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• 2010

Allelopathic activity of rotation crop residues to common weeds and selectivity of crops were studied for developing an alternative weed control strategy in upland organic farming. All rotation crop residues with various ratios suppressed weed growth, but the growth of crop species stimulated a little when those were grown with the mixture of rotation crop residues except a few crop species. Among the rotation crop residues used in this study hairy vetch was the most effective, followed by Chinese milkvetch, barley and rye in suppression of weed growth. The 90:10 (crop:soil, v/v) treatments incorporation rate of crop residues such as hairy vetch and Chinese milkvetch suppressed completely the growth of all weed species tested in this study. The effect of crop residues on suppression of weed growth reduced to 90% when the incorporation rates decreased to 60% [60:40 (crop:soil, v/v). It was noticed that broadleaf weed species were more susceptible to rotation crop residues than grass weed species. In the influence of crop residues on the crop growth, no growth inhibition was found in red pepper, lettuce and perllia at any incorporation rates, but tomato, cucumber and corn were slightly inhibited in a few cases at their highest incorporation levels. This study demonstrated that rotation crop residues especially hairy vetch and Chinese milkvetch have high herbicidal effects against weeds without inhibiting the growth of crop species.

• Applied Biological Chemistry
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• v.37 no.2
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• pp.115-123
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• 1994

Allelopathic activity of the volatiles from leaves of Perilla frutescens an Artemisia asiatica was determined on the basis of bioassay, which tested germination and seedling growth of radish, rice, mung bean and lettuce. Seedling growth was more inhibited by phytotoxic volatiles than germination. Volatile components collected by headspace cold trapping-Tenax GC adsorption were analyzed by GC-MS. Fifteen volatile components in P. frutescens and 15 components in A. asiatica were identified. By steam distillation-extraction, 4 flavor components in P. frutescens and 10 components in A. asiatica were identified. The inhibitory activity of the fractions, obtained by steam distillation-extraction, was determined by virtue of bioassay on radish. Volatile allelochemicals of the most active fraction, neutral fraction, isolated from P. frutescens contained 9 components. In A. asiatica, 24 volatile allelochemicals were identified.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2002.02a
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• pp.3-5
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• 2002

This study was carried out to get better understandings about morphological, ecological, and genetical characteristics of annual bluegrass collected from different golf courses in Korea and eventually to establish a successful control strategy. Twenty five local lines of annual bluegrass collected from 20 golf courses in Korea were classified into annual or perennial type on the basis of morphological characteristics. Twelve local lines showing obvious morphological differences were selected and then genetically assessed using RAPD analysis. Classification of the 12 local lines through RAPD analysis were considerably similar to that determined by both of morphological differences and phenotype. Responses of the two types of annual blugrass to herbicides were also examined. Shoot growth of annual bluegrass was significantly suppressed by flazasulfuron and the annual type was more susceptible than perennial type, regardless of flazasulfuron concentrations used. By pendimethalin treatment, there was no clear difference in susceptibility between the two types of annual bluegrass. However, by the treatment of dithiopyr, annual type was more sensitive than perennial type in both shoot and root growth. Nine tree species were screened to detect their allelopathic potential on turfgrasses and annual bluegrass. Acacia (Robinia pseudo-acacia) leaves showed selective inhibition in the shoot and root growth as well as their seed germination when treated with 2% and 10%(v/v) of the extract. However, the other leaf extracts except acacia inhibited non-selectively the growth of three turfgrass species such as bentgrass, perennial ryegrass and zoysiagrass and annual bluegrass. The PAL activities of annual bluegrass increased at 24 h after treatment of acacia leaf extract and peaked at 36 h and then decreased till 60h. The highest PAL activity was observed at 36h after treatment of 10%. The highest activity of CA4H in annual bluegrass was observed at 2h after treatment of acacia extract and the level was 4 times greater than that of the control. The phenolic acids such as p-coumaric acid, salicylic acid and ferulic acid were increased with the treatment of acacia leaf extract. The chloroplast membrane and cell wall of annual bluegrass were destroyed by treatment of acacia leaf extract and its inner materials were released. The membranes in annual bluegrass cells might be destroyed by phytotoxic compounds from acacia leaf extract.

• Korean Journal of Organic Agriculture
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• v.24 no.1
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• pp.73-85
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• 2016

This study was carried out to allelopathic effects of aqueous extracts on Coronopus didymus in order to investigate the competitive dominant in plant ecosystem and possibility application in natural herbicide. Number of species and species diversity for close to patch of C. didymus was decreased gradually site #1 (7, 1.76), site #2 (5, 1.34) and site #3 (5, 1.25). It was generally decreased the relative germination ratio (r=-0.731, p<0.01), the mean germination time, the relative elongation ratio (r=-571, p<0.01, r=-0.730, p<0.01), the relative fresh weight (r=-0.743, p<0.01), development of root hairs of receptor plants by concentration of the aqueous extracts from C. didymu. But they were different from the growing regions, the kind of receptor plants and the treatment of the aqueous extracts. Especially, it was differently effected among growing regions that inhibited more radicle than shoot by the aqueous extracts concentration of C. didymus. Total phenolic compound in the aqueous extracts of C. didymus analyzed about $23.0{\pm}1.1mg/g$. Total phenolic compounds of soil in survey area was increased gradually site #1 ($0.072{\pm}0.002mg/g$), site #2 ($0.082{\pm}0.003mg/g$) and site #3 ($0.092{\pm}0.004 mg/g$). We think that the aqueous extracts of C. didymu showed allelopathic effects on other plants. Therefore, C. didymu hold the competitive dominant of plant ecosystem in Jeju Island and possibility application of natural herbicide.