• The Korean Journal of Ecology
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• v.27 no.5
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• pp.307-310
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• 2004

It was found that seed germination and seedling growth of selected species were inhibited by phytotoxic substance released from fir trees. The aqueous extracts of leaves caused significant inhibition in the seed germination of the receptor plants, Whereas seed germination of some species was not inhibited in extracts of leaves, but seedling elongation of the receptor plants was also decreased by the aqueous extract. Dry weight growth was slightly increased in lower concentration of the extract, while that was proportionally inhibited by higher concentration of the extracts. Chemical substances of fir trees were shown the biological toxicity. The GC method was employed for analysis of phytotoxic chemicals and sixteen chemical substances were identified such as benzoic, phenylacetic, etc. Also 33 volatile substances were identified from the fir tree. These chemical compounds are assumed the substances related to allelopathic potential of Abies holophylla plant species.

• The Korean Journal of Ecology
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• v.21 no.2
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• pp.151-156
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• 1998

the phytotoxic effects of volatile substances emitted from the tomato plant (Lycopersicon esculentum) on receptor plants such as Bidens bipinnata, Plantago asiatica, Lactuca sativa, Eragrositis ferruginea and Achyranthes japonica were investigated. Bolatile substances from the leaves inhibited seedling growth of receptor plants in the laboratory tests. The inhibition response varied with the concentration of compounds. To identify the phytotoxic compounds from tomato plant a GC/MS method was employed. Forth compounds, such as trans-2-hexeal, linalool, phenylacetaldehyde, methlsalicylic acid and tetradecanaic acid were identified from the essential oil of tomato plants. The findings suggest that the tomato plant may have allelopathic potential.

• Korean Journal of Plant Resources
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• v.7 no.2
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• pp.115-119
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• 1994

These experiments were conducted to determine the effects of Sorghum allelopathic substances on the callus growh of several weeds and crops. 1. When substances extracted from allelopathic Sorghum(Sorghum bicolor L.) were treated on medium, growth of callus of several weeds and crops were in-hibited. The degree of inhibition differed depending on the genotypes, ranging from 50 to 90% com-pared with that of control. 2. The extracts of above 5% Sorghum inhibited the callus growth of Che-nopodium albun L., Commelina communis L., and .Ammaranthus retroflexus L.and showed in-hibition rate of above 70% in callus growth. These results indicate that we could investigate theallelopaihy effect by using in vitro system. 3. The suitable explant for callus induction fromallelopathic plants was immature embryos, the callus induction rate differed depending on the geno-type, growth regulators and concentrations. In general, the addition of 2, 4-D and NAA onto medium increased the rate and amount of callus.

• The Korean Journal of Ecology
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• v.23 no.6
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• pp.431-434
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• 2000

To examine the allelopathic potentials of Chrysanthemum boreale, aqueous extracts and essential oil of the plant were used in these experiments. Seed germination of the receptor species was inhibited by the aqueous extracts and the inhibitory effect was increased in proportion to the concentration of extracts. In contrast, seedling elongation showed varied results. Achyranthes japonica, Bidens bipinnata, Raphanus sativus var. hortensis for. acanthiformis, Plantago asiatica, Pimpinella brachycarpa and Lactuca sativa were inhibited by increasing concentration of the aqueous extract, while Brassica campestris subsp. napus var. pekinensis and Echinochloa crus-galli were stimulated by the extract. Dry weight was also inhibited proportionally by increasing concentration of the aqueous extract, while some species were stimulated by a lower concentration of the extract. The volatile substances of C. boreale did not affect the seed germination of receptor plants, but seedling elongation and dry weight of some species were inhibited dose-dependently. Root hair development of selected plants was inhibited along with the concentration of essential oil. The above mentioned results, therefore, confirmed that the natural substances from C. boreale had allelopathic potentials to other plants.

• The Korean Journal of Ecology
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• v.23 no.4
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• pp.323-329
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• 2000

The allelopathic effects of volatile substances from Chamaecyparis obtusa (S. et Z.) Endl. were examined on the germination and seedling growth of some plant species, and on the population growth of some microorganisms. The germination and seedling growth of the receptor plants were suppressed more severely by leaf and fruit essential oils than by those of other parts. Colonial growth of fungi was severely inhibited by essential oils extracted from leaves and fruits. The development of root hairs of the receptor plants was also severely inhibited by the essential oils. The cortical cells at the root tips of Lactuca sativa L. treated with essential oils showed contraction of the cytoplasm, resulting in plasma membranes becoming detached from the cell walls and the cells metamorphosing irregularly. Accumulation of lipid granules inside the contracted cytoplasm and degeneration of mitochondrial cristae were also observed.

• 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.

• 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.

• Korean Journal of Weed Science
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• v.17 no.1
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• pp.52-58
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• 1997

Rice (Oryza sativa L.) contains water-soluble substances that inhibit the germination of Echinochloa crus-galli. This study investigated the allelopathic potential of rice in which rice had been grown with E. crus-galli in the field. Extracts of forty-seven rice varieties were screened for allelopathic potential in the laboratory. Double distilled water was used as a control. Based on the germination percentage, the varieties may be classified in the following order of decreasing inhibition : Namweon(36%) and Gyehwa(38%) hulls extracts and Sambaeg(43%) and Seoan(46%) leaves extracts. In the comparison of allelopathic activity test between leaves and hulls extracts, hulls extracts contain more allelopathic toxic substances. In the effect of concentration treatment on the six levels of extract solutions(3, 6, 12, 25, 50, 100%, v/v) germination percentage was significantly inhibited as the extract concentration increased. The highest concentration(100%) caused the greatest reduction in E. crus-galli. Allelopathic potential effects were significantly different among the various varieties and between '94 and '95 year extracts. The results indicate that there are genetic differences among varieties for allelopathic potentiality on E. crus-galli. Allelopathic potential in the ecological aspects can be decided through variety selection.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.421-430
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• 1997

This experiment was conducted to detect the presence of allelopathic substances in the leaves of Ginkgo biloba L. Water extracts from G. biloba leaves which collected at different season markedly inhibited the germination and growth of O. sativa, E. crus-galli, D. sanguinalis, and L. sativa, indicating the presence of biological substances. Linolenic and palmitic acid were the major fatty acids of G. biloba leaves. The biochemical substances such as salicylic arid, p-coumaric acid, catechol, hydroquinone, orchinol, ferulic acid, phloroglucinol, and umbelliferone etc., belonging to the phenolic, compounds were, detected in a large amount, which may be responsible for exhibition inhibitory effects. The common phenolic compounds were detected in the early-harvested and late-harvested G. biloba leaves were salicylic and p-coumaric acid. All these compounds were related to the allelopathic activities in G. biloba leaves.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.4
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• pp.303-307
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• 2003

Some Compositae plants are known to contain biologically active substances that are allelopathic to weeds species as well as antioxidant to foods. Aqueous extracts from leaves of 3 plant species, Cirsium japonica, Kalimeris yomena, and Lactuca saliva, were bioassayed against alfalfa (Medicago saliva) to determine their allelopathic effects. The extracts applied on filter paper in bioassay significantly inhibited root growth of alfalfa. Extracts of 20 g dry tissue $\textrm{L}^{-1}$ from Lactuca sativa showed the most inhibitory effect on alfalfa seedling growth and followed by Cirsium japonica and Kalimeris yomena. Oxidative stability by Rancimat method and antioxidant activity by TBA method for the ground samples were the greatest in Lactuca sativa although were less than that of a commonly used antioxidant, 1% ascorbic acid. Antioxidant activity of methanol extracts on storing meat was stably kept for 28days and was excellent compared to control. These results suggest that three Compositae plants have potent allelopathic and antioxidant effects, and that their activities differ, depending on plant species.