• 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.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.51-58
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• 1999

Korean native plants and naturalized plants were analyzed for allelochemicals, and their antimicrobial effects were studied. The difference in soluble solid contents between Korean native plants and naturalized species was not significant, and the Korean native plant, Solanum nigrum showed the highest soluble solid content of 90 mg/ml. The ethanol extract of the Korean native plant, Solanum nigrum showed antifungal activity to Aspergillus phoenicis KCTC 1228, with a clear zone of 18 mm, and spore formation was not observed from the treatment. The naturalized plants Ambrosia artemisiifolia var. elatior and Erigeron canadensis showed inhibition of spore formation and the clear zones were at 24 mm and 22 mm, respectively. The clear zones of Aspergillus phoenicis KCTC 1228 treated with ethanol extrats of Phytolacca americana and Rudbeckia bicolor were 22 mm and 19 mm, respectively, and spore formation was observed from the treatment. The Korean native plant, Solanum nigrum and naturalized plants, Phytolacca americana and Ambrosia artemisiifolia var. elatior showed antimicrobial activity against Bacillus sphiaericus 2362, and Bacillus sphiaericus 2297, Bacillus thuringiensis var. subtilis and Baicillus thuringiensis var. cereus. The antimicrobial activity of Ambrosia artemisiifolia var. elatior showed the largest clear zone of 32 mm against Bacillus thuringiensis var. subtilis. In general, the more soluble the solid contents of the extracts, the greater were the antifungal and antimicrobial activities. The phenolic compounds from the Korean native plant, Solanum nigrum and the naturalized species, Phytolacca americana and Ambrosia artemisiifolia var. elatior were analyzed by high performance liquid chromatography. Three phenolic compounds including hydroquinone were identified in Solanum nigrum. In contrast, five and seven phenolic compounds were identified in Phytolacca americana and Ambrosia artemisiifolia var. elatior, respectively. The antifungal activity against Aspergillus phoenicis KCTC 1228 was found to be due to the coumaric and benzoic compounds.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.173-182
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• 1992

Regardless of the test species, germination was adversely affected by the different concentrations of the acidic and neutral fractions of sunflower root exudates while the basic and aqueous fractions had no effect on germination. In both test species, root lengths were inhibited slightly more than shoot lengths. Significant reduction in fresh weights of the test species was observed when the test species were treated with the acidic and neutral fractions but not with the basic and aqueous fractions. Six compounds, hydroquinone, ${\beta}$-resorcyclic acid, vanillic acid, caffeic acid, salicylic acid, and quercetin, were characterized from the acidic fraction. Seven compounds, hydroquinone, gentisic acid, ${\beta}$-resorcyclic acid, vanillic acid, caffeic acid, ferulic acid, and quercetin, were elucidated from the neutral fraction.

• Proceedings of the Korean Society of Crop Science Conference
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• 2003.05a
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• pp.69-69
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• 2003

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.86-92
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• 2016

This study was conducted to evaluate the allelopathic effect against the regeneration of the seedling and to identify the presence of allelochemicals in Picea jezoensis natural population in Jirisan. Water-soluble extracts from leaves of different competition plants were collected to test their effects on seed germination and seedling growth of P. jezoensis. Phenolic compounds from leaves were quantified using GC/MS. The seed germination rate and seedling growth of P. jezoensis was reduced by extracts of all competition plants leaves. Monoterpenoids compound, which are generally well known in the allelochemicals has been detected in the leaf extracts. In conclusion, allelopathic chemicals of competition vegetation in P. jezoensis natural population could inhibit the seed germination and seedling growth of P. jezoensis, that is considered as a result of the lower seedling establishment.

• Journal of Ginseng Research
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• v.48 no.2
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• pp.229-235
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• 2024

Background: Plant health is directly related to the change in native microbial diversity and changes in soil health have been implicated as one of the main cause of root rot. However, scarce information is present regarding allelopathic relationship of Panax notoginseng root exudates and pathogenic fungi Fusarium oxysporum in a continuous cropping system. Methods: We analyzed P. notoginseng root exudate in the planting soil for three successive years to determine phenolic acid concentration using GC-MS and HPLC followed by effect on the microbial community assembly. Antioxidant enzymes were checked in the roots to confirm possible resistance in P. notoginseng. Results: Total 29 allelochemicals in the planting soil extract was found with highest concentration (10.54 %) of p-hydroxybenzoic acid. The HPLC showing a year-by-year decrease in p-hydroxybenzoic acid content in soil of different planting years, and an increase in population of F. oxysporum. Moreover, community analysis displayed negative correlation with 2.22 mmol. L^-1 of p-hydroxybenzoic acid correspond to an 18.1 % population of F. oxysporum. Furthermore, in vitro plate assay indicates that medium dose of p-hydroxybenzoic acid (2.5-5 mmol. L^-1) can stimulate the growth of F. oxysporum colonies and the production of macroconidia, as well as cell wall-degrading enzymes. We found that 2-3 mmol. L^-1 of p-hydroxybenzoic acid significantly increased the population of F. oxysporum. Conclusion: In conclusion, our study suggested that p-hydroxybenzoic acid have negative effect on the root system and modified the rhizosphere microbiome so that the host plant became more susceptible to root rot disease.

• The Korean Journal of Ecology
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• v.8 no.1
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• pp.15-19
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• 1985

A number of field surveys have been performed in larch (Larix leptolepsis) forest floor in which any seeding of this species never find ther. In laboratory work, aqueous extracts from leaves, roots and stems of larch were provided and used to bioassay. Among them, germination and seedling growth of selected species were the most inhibitory in leaves extracts. Though germiation percentage of a species showed high compared with control, its dry weight after a given period grown were clearly low. The results due to be considered by allelopathic effect. And syringic acid and p-hydroxybenzoic acid were identified by HPLC from larch leaves. It is assumed that these phenolic acids affect on other species as allelochemicals of larch.

• Journal of Plant Biology
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• v.30 no.1
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• pp.59-67
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• 1987

To verify allelopathic effect of tomato plants a number of labovatory experiments, seed germination and seedling growth with aqueous extracts and leachates form the tomato plants, have performed. Germination percentage of the tested species was decreased by treatment with leaf, stem and root extracts as extracting time elapses. The leaf extract more inhibits the germination of the seeds than both stem and root extracts. Leachate collected from the tomato plants decreases as much as 50% of the growths in elongation as well as dry weight of seedlings of lettuce and egg plant. It is observed that with a paired-plants grown in U tube pot the tomato roots have excreted allelochemicals to inhibit the growth of the tested species and volatile substances from the tomato plants have suppressed to dry weights of lettuce, to elongation and dry weights of grapevine planted near the tomato plants.

• Journal of Forest and Environmental Science
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• v.31 no.2
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• pp.109-118
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• 2015

Allelopathy is an ecological phenomenon that refers to the beneficial or harmful effects of one plant on another plant, both crop and weed species, by the release of organic chemicals (allelochemicals) from plant parts by leaching, root exudation, volatilization, residue decomposition in soil and other processes in both natural and agricultural systems. Allelopathy can affect many aspects of plant ecology including occurrence, growth, plant succession, the structure of plant communities, survival, dominance, diversity, and plant productivity. In this review, we describe the concept of allelopathy, some mechanisms of operation within plants and then focus on a select number of gymnospermous tree genera: Ephedra, Pinus, Taxus, Cedrus, Juniperus, Picea, Cunninghamia and Araucaria. Pinus, Taxus (yew) and Cedrus (cedar) trees have a strong negative allelopathic effect on the germination, growth, or development of other plant species in the forest community.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.520-526
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• 2007

To select submerged macrophytes to suppress growth of Microcystis aeruginosa through releasing allelochemicals, we conducted growth experiments with water from patches of submerged macrophytes and with aqueous extracts of those submerged macrophytes. In the first experiment, growth rates of M. aeruginosa decreased as biomass of Myriophyllum spicatum and Hydrilla verticillata increased. In the second experiment, M. aeruginosa showed approximately 50% growth reduction with extracts from M. spicatum and 24% reduction with extracts from Ottelia alismoides. Both M. aeruginosa growth experiments with water and plant extracts suggest that M. spicatum would be the best candidate to reduce M. aeruginosa growth.