• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.5
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• pp.310-315
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• 2000

Alfalfa (Medicago sativa L.) plants have been reported to contain water-soluble substances that are autotoxic as well as allelopathic. Laboratory experiment through a petri-dish assay with imbibed seeds was conducted to evaluate both autotoxic and allelopathic effects of alfalfa leaf extracts on the germination and early seedling growth of alfalfa, red clover, crested wheatgrass, and Russian wildrye. Alfalfa seed germination was delayed dependent on extract concentration, with no difference in final germination at 72 hours. Root growth of alfalfa was stimulated up to 14% above control at very low concentrations of both leaf and stem extracts of alfalfa and was significantly reduced at extract concentration of more than 0.5g dry tissue/L (${gL}_{-1}$). Leaf extracts were generally more autotoxic for root growth than were stem extracts. Hypocotyl growth was not affected by all the concentrations of both leaf and stem extracts. Root length of legumes was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Hypocotyl growth of two legume plants and plant height of two grasses were not influenced by extracts. Seed germination and root growth of legumes were more inhibited by aqueous extracts of alfalfa leaf than were those of grasses. This result indicates autotoxic effect of alfalfa leaf extracts seems to be greater than allelopathic effect.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.25-31
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• 2002

This study was conducted to investigate allelopathic potential from Korean Lycoris radiata HERB. Two different solvents such as MeOH and water were used for extraction from Lycoris radiata HERB. Both extract showed inhibitory effect on the germination of barnyardgrass and lettuce seeds, indicating that this species contained the biologically active substances. The inhibitory substance extracted from bulbs of this species was identified by GC-MS as lycorenan, a kind of alkaloid.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.295-305
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• 1994

Greenhouse and laboratory studies were conducted to investigate the allelopathic potential of alfalfa and vetch residues on soybean and corn using various extract concentrations (0, 5, 10, 15 and 20%, w/v) and residue rates (0, 0.25, 0.5, 0.75 and 1%, w/w). Aqueous extracts of alfalfa (Medicago sativa L.) and vetch (Vicia spp.) exhibited an allelopathic effect on soybean and corn seed germination, seedling length and weight. The degree of inhibition significantly increased as the aqueous extract concentration increased. Alfalfa and vetch 20% extracts reduced soybean seed germination, seedling length and weight by 35%, 57%, 32% and 15%, 42%, 25% respectively, when compared to control. Corn germination, seedling length and weight was inhibited by 20%, 23%, 38% by alfalfa and 19%, 18%, 35% by 20% vetch extracts. Alfalfa and vetch extracts inhibited secondary root formation and branching as the extract concentration increased. Alfalfa and vetch 20% extracts inhibited by 41% and 32% secondary root numbers, respectively as compared to control. It was found that the aqueous extract of alfalfa resulted in greater reduction in germination, seedling length and weight of soybean than that of vetch. Alfalfa and vetch 1% residue rate inhibited soybean plant height by 30% and 10%, leaf area by 31% and 23%, and dry weight by 18% and 1%, nodule number by 27% and 20% also. Alfalfa and vetch residue significantly enhanced plant height, leaf area and dry weight of corn. The maximum stimulation occurred with 0.25% and 1% of alfalfa and vetch residue rates, respectively. Plant height, leaf area, and dry weight increased by 23%, 59%, 58% and 17%, 52%, 94% with alfalfa and vetch residues of 0.25% and 1%, respectively. This study demonstrates that there is an allelopathic potential resulting from alfalfa and vetch residues on soybean growth and yield. It also suggests that these residues may affect crop growth and development due to the inhibitory or stimulatory effects of allelochemicals existing in the residue.

• Proceedings of the Botanical Society of Korea Conference
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• 2000.04a
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• pp.16-16
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• 2000

• Proceedings of the Korean Society of Crop Science Conference
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• 1994.10a
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• pp.5-6
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• 1994

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.4
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• pp.345-350
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• 2003

A series of aqueous extracts and residues from leaves, stems, roots, pods and seeds of Korean black soybean (Glycine max (L.) Merr.) were assayed against alfalfa (Medicago sativa) and barnyard grass (Echinochloa crus-galli) to determine their allelopathic activities through petri-dish and greenhouse experiments, and the results showed highest inhibition in the extracts or residues from the seeds, and followed by pods. The extracts of 40g dry tissue $\textrm{L}^{-1}$ applied on filter paper in petri-dish bioassay significantly inhibited root growth of alfalfa, and especially extracts from seeds and pods reduced root length of alfalfa more than those from leaves, stems, or roots. Plant height, root length, shoot and root dry weights of barnyard grass were reduced significantly by residue incorporation of seeds and pods as the incorporated amount increased. These results suggest that black soybean plants had herbicidal potential, and their activities were exhibited differently depending on plant parts.

• 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.

• The Korean Journal of Ecology
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• v.14 no.2
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• pp.149-157
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• 1991

To find out allelopathic potential of naturally occurring substances emitted form pinus korairnsis, water extracts and volatile sudstances of the tree materials werw provided and used for tests such as seed germination and seedling growth test. In general, the more was the concentration of the extracts and essential oils, the worse was growth effects of the selected species. The germination an the growth were inversely proportional to the concentration of the extracts and the essential oils of p. koraiensis. in other words, the chemical substances had the biological toxic activity. gc and gc/ms methods were employed for analysis and identification of phytotoxic substances from the tree leaves. Sixteen chemical compounds were identified from water extracts and nineteen from essential oils of p. koraiensis leaves. Through the experiment on germination and seedling growth test, the chemical substances naturally occurring from p. koraiensis seemed to be responsible for the allelopathic potential in this study.

• 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.