• 한국작물학회지
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• 제45권5호
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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.

• 한국작물학회지
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• 제49권1호
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• pp.7-11
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• 2004

Alfalfa (Medicago sativa L.) plants have been reported to be autotoxic as well as allelopathic. Laboratory and greenhouse experiments through petri-dish and pot test were conducted to determine autotoxic effects of alfalfa leaf and soil extracts on the germination or early seedling growth of alfalfa, and to evaluate allelopathic effects of alfalfa leaf residues on alfalfa, barnyard grass, com, eclipta and soybean. Alfalfa seed germination was delayed depending on aqueous extract concentration, with no difference in final germination after 48 hours. Alfalfa root length was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Root growth of alfalfa was significantly inhibited at extract concentration of more than 1 g dry tissue/L (g $\textrm{L}^{-1}$). Hypocotyl growth, however, was not affected by all the concentrations of leaf extracts. Soil extracts from 4-yr-old alfalfa stand significantly reduced alfalfa root length by 66%, while soil extracts from 0,1, and 3yr-old stand stimulated root length up to 14-32% over the control. Residue incorporation with dry matters of alfalfa leaf at 100 g $\textrm{kg}^{-1}$ reduced seedling length of several crop and weed species, ranging from 53 to 87% inhibition. Addition of nutrient solution into alfalfa leaf extracts alleviated alfalfa autotoxic effect. This result indicates alfalfa leaf and soil extracts or residues could exert autotoxic as well as allelopathic substances into soil environments during and after establishment.

• The Korean Journal of Ecology
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• 제23권6호
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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.

• Plant Resources
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• 제7권1호
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• pp.47-53
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• 2004

Several wild plant species are known to contain biologically active substances that are allelopathic to weed species as well as antioxidant to foods. Plant extracts or residues from leaves of 4 species, Achyranthes japonica (speedwell), Cucumis sativus (Cucumber), Trifolium repens (white clover), and Vicia angustifolia (narrowleaf vetch) were bioassayed against Medicago sativa (alfalfa) or Echinochloa crus-galli (barnyard grass) to determine their allelopathic effects, and used for measurement of antioxidant activities. The aqueous extracts applied on filter paper significantly inhibited root growth of alfalfa. Aqueous extracts or residues from V. angustifolia showed the most inhibitory effect on alfalfa or barnyard grass seedling growth and followed by A. japonica and T. repens. Oxidative stability by Rancimat method, antioxidant activity by TBA (2-thiobarbituric acid) method and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity for the ground samples or methanol extracts were the greatest in V. angustifolia, although were less than those of commonly used antioxidants, BHT (butylated hydroxytoluene) and ascorbic acid. These results suggest that the wild plant species had potent allelopathic and antioxidant activities, and that their activities differed depending on plant species.

• 한국잡초학회지
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• 제11권2호
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• pp.122-127
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• 1991

볏짚과 보리짚의 생리활성물질(生理活性物質)이 상추 발아(發芽) 및 포장(圃場) 잡초발생(雜草發生) 및 생육(生育)에 미치는 영향(影響)을 검토(檢討)하기 위하여 볏짚 분말(粉末)을 모래와 혼합(混合)하여 상추를 발아(發芽)시켰으며, 포장(圃場)에서 볏짚과 보리짚을 여러수준으로 피복(被覆)하여 잡초(雜草) 생육(生育) 억제정도(抑制程度)를 본 결과(結果)를 요약(要約)하연 아래와 같다. l. 볏짚분말(粉末)을 모래와 혼합(混合)하여 상추 발아(發芽)시 발아(發芽)가 억제(抑制)되어 발아억제물질(發芽抑制物質)의 존재(存在)를 추론(推論)할 수 있었다. 2. 볏짚 피복(被覆)시 $m^2$ 당 500g 이상(以上)이면 뚝새풀의 생장(生長)에 35% 이상(以上) 억제효과(抑制效果)가 있었다. 3. 보리짚을 $m^2$당(當) 200g 피복(被覆)할 경우 피와 바랭이의 생장(生長)을 억제(抑制)하였으며, 300g이상(以上) 피복(被覆)하연 97%의 억제효과(抑制效果)가 있었다. 4. 또한 보리짚 피복(被覆)시 화본과(禾本科)>사초과(沙草科)>광엽(廣葉) 잡초(雜草) 순(順)으로 억제효과(抑制效果)가 있었다.

• The Korean Journal of Ecology
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• 제22권2호
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• pp.85-88
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• 1999

Aqueous and dichloromethane (DCM) extracts of leaves, root bark and inflorescences of Parthenium hysterophorus L. at various concentrations were used to quantify its allelopathic potential against Indigofera tinctoria, Amaranthus viridis, A. gangeticus, Phaseolus mungo (cv. CO 1), Sorghum vulgare (cv. SPT- 462). Pennisetum typhoideus (cv. WCC-75) and Eleusine corocana (cv. CO 1). The aqueous extracts were more inhibitory than the DCM extracts to the germination and seedling growth of the plants studied. The relative rate of inhibition increased in the order of inflorescences. leaves and root bark in the aqueous extracts. whereas DCM root bark and inflorescences extracts were promoted at lower concentrations.

• The Korean Journal of Ecology
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• 제27권5호
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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.

• 한국자원식물학회지
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• 제7권2호
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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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• 제20권4호
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• pp.233-238
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• 1997

To evaluate allelopathic effect of volatile chemicals and phytohormones, seed germination and seedling growth test of Lactuca sativa have performed in laboratory experiments. Among used chemicals terpienen-4-ol was the most inhibitory to seed germination of lettuce. ABA and GA inhibited seed germination at $5{\times}10^{-6}M$ concentration but promoted germination at $2.5{\times}10^{-5}M$ and $5{\times}10^{-5}M$. ABA and GA alleviated volatile chemical-induced inhibition of seed germination and seedling elongation of lettuce.

• The Korean Journal of Ecology
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• 제24권1호
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• pp.61-66
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• 2001

돼지풀 잎에서 검정된 monoterpenoids는 약 29종이었고, 그 가운데 octene, $\alpha$-ponene, $\beta$-myrcene, 1.3.6-octatrine, endo-borneol, (-)-bomyl acetate의 함량이 높다. Monoterenoids 총 함량은 초봄부터 점차 증가하여 7월에 가장 높았고 그후 감소하였다. 돼지풀 잎에 함유된 휘발성물질은 수용체 유식물의 뿌리와 줄기 생장에 억제효과를 나타내었으며, 생엽량의 증가에 따라 억제효과도 증가하였다. 이에 따른 억제효과 차이의 유의성은 대부분이 P<0.05 수준이었다. 억제효과는 처리식물에 따라 큰 차이가 있었다. 돼지풀 생엽의 채취시기에 따른 유식물 생장 억제효과의 경향성은 대부분의 처리식물에서 7월>6월$\geq$5월 순 이었다.