• Journal of Korea Foresty Energy
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• v.22 no.3
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• pp.11-19
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• 2003

Allelopathic effects of black locust(Robinia pseudoacacia L.) was evaluated through germination tests using 13 different species including R. pseudoacacia itself. The water extract from leaf or root of R. pseudoacacia was separately tested. Seed germination of several species was inhibited in the presence of leaf or root extract, although the level of germination was in a wide range depending on the species. Seed germination of R. pseudoacacia was suppressed by 30 % in its leaf extract. Among tested tree species, Hibiscus syriacus and Alnus frma showed significantly inhibited germination in the root extracts whereas Thuja orientalis exhibited germination inhibition in the leaf extract. HPLC was carried out to identify allelochemicals in extracts of leaf and root using eight authentic phenolic compounds that are known to be responsible for allelopathy. The major phenolic compounds occupying about 40 % of total phenolic acids were gentisic acid in leaves and vanillic acid and syringic acid in roots. The leaves contained 7 times more phenolic acids than the roots. Among 8 tested phenolic compounds vanillin was detected only in roots and coumaric acid in leaves. Consequently, 3 out of 13 species showed significantly inhibited germination due to leaf or root extract. This germination test indicates that the inhibitory allelopathic effect by R. pseudoacacia is caused by chemical interaction not by nutritional competition and that the allelochermicals of black locust act species-specifically. No specific influence of the total amount of phenolic compounds on the allelopathic inhibitory germination and the synergic effect by each phenolic compound may play a role for the allelopathic effect by R. pseudoacacia.

• 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.

• Korean Journal of Weed Science
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• v.18 no.3
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• pp.214-224
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• 1998

This study was conducted to develop labor and chemical cultural practice improvement for weed control in ginseng field. Five crop species were screened in vitro and three crop extracts were sprayed in the test allelopathic effect for weed species. Methyl alcohol extracts of rice, oat, rye and wheat straw showed inhibitory effect on the germination of six weed species, Amaranthus retroflexus, Chenopodium album, Arthraxon hispidus, Digitaria adscendens, Echinochloa crus-galli, and Setaria viridis. Especially, extract of oat straw was most effective to inhibit the germination of six weed species tested. Also, spraying the extract solution of rice, rye and wheat straw was effective to inhibit the growth of weeds in ginseng field. Ginseng root length, diameter, fresh and dry weight in extract spraying plot were higher than those of non-treatment plot.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.30-35
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• 2004

Compositae plants are known to contain biologically active substances that are allelopathic to agricultural crops as well as weed species. Aqueous extracts from leaves of Xanthium occidentale were assayed against alfalfa (Medicago sativa) to determine their allelopathic effects, and the result showed that the extracts applied onto filter paper significantly inhibited seed germination as well as root growth of alfalfa. Untreated seeds germinated in 60h, but extract concentrations greater than 30g $\textrm{L}^{-1}$ delayed seed germination. The extracts significantly inhibited seed germination of alfalfa, and $\beta$-amylase activity of alfalfa and barley seeds during 24-36 hours after treatment. Aqueous extracts of 40 g $\textrm{L}^{-1}$ from X. occidentale were completely inhibited the hypocotyl and root growth of alfalfa. Aqueous leaf extracts showed the highest inhibitory effect and followed by root and stem extracts. Early seedling growth of both alfalfa and barnyard grass (Echinochloa crus-galli) was significantly reduced by methanol extracts. By means of high-performance liquid chromatography, chlorogenic acid and trans-cinnamic acid were quantified as the highest amounts from water and EtOAc fractions, respectively. BuOH and EtOAc fractions of X. occidentale reduced alfalfa root growth more than did hexane and water fractions. The findings of the bioassays for aqueous or methanol extracts reflected that the inhibitory effect of extract was closely related to the level of responsible allelochemicals found in plant extracts.

• 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.

• The Korean Journal of Ecology
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• v.16 no.3
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• pp.275-285
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• 1993

To study allelopathic porential of naturally occurring substances emitted from Pinus koraiensis, the effects of water exrracts and volatile substances of the tree on callus induction and bacterial culture were examined. The induction and growth of callus were inversely proportional to the concentration of the extracts and of the essential oils supplemnted to Murashige and Skoog's media. However, low concentration(5μl/l) of essential oil promoted callus growth. In germiculture of several bavteria, the extracts of Pinus koraiensis markedly showed the inhibitory effects on bacterial growth. It was, therefore, confirmed that the KDICical substances of Pinus koraiensis tree clearly showed that biological toxic activity at high concentrations.

• 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.

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.159.3-160
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• 2001

No Abstract, See Full Text

• The Korean Journal of Ecology
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• v.20 no.6
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• pp.413-421
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• 1997

Ecological characteristics of Rumex acetosella have been studied both in the laboratory and in the field. R. acetosella grows well straight up after germination, elongating and thickening their rhizomes with sprouts erupting along their bodies of the rhizome. The number and development of leaves and ramets reach their peak by April. The size of leaves and the cover degree of the plant increase from April to May. R. acetosella is an ephemeral, a short life mode plant, finishing its life cycle in July or August. The germination and seedling growth of selected species exposed to aqueous extracts of R. acetosella were in inverse proportion to concentration. The growth of Rumex japonicus and Digitaria sanguinalis cultivated in soil with R. acetosella was more inhibited than that of the control. Twelve chemical compounds were identified from R. acetosella by GC and HPLC and verified by bioassay with the same chemical reagents. It would be assdumed that these chemical substances are responsible for the allelopathic effect of R. acetosella. In short, R. acetosella plants grow vigorously from April and maintain their superior competitive ability to other plants in forming their communities by emitting chemical substances into their environment.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.59-63
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• 1999

To verify allelopathic effects, seed germination and seedling growth test, chemical analysis and bioassay of selected species were carried out with naturally occurring chemicals of Artemisia capillaris. Seed germination ratio of Calamagrostis arundinacea. Youngia denticulata and Lactuca indica var. laciniata showed decrease in proportion to increase in aqueous extracts concentration of A. capillaris. while that of Cosmos bipinnatus and Leonurus sibiricus did not. However, dry weight growth of selected species treated with the same extracts as the above experiment was inhibited remarkably compared to the germination test. In the test at different concentrations of essential oil from A. capillaris, seedling growth of A. princeps var. orientalis and Plantago asiatica was suppressed according to the concentration of the essential oil, and root growth of the selected species was more inhibitory than that of shoot growth. Thirty-six chemical compounds were identified from A. capillaris plant by gas chromatography. Seven compounds out of 36 were bioassayed, and terpinen-4-ol was the most toxic among the tested substances.