• The Korean Journal of Ecology
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• v.11 no.2
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• pp.65-76
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• 1988

A number of laboratory and field experiments have performed with aqueous extracts from fresh leaves, fallen leaves and roots of Pinus rigida in order to investigae the effetct of the pine tree. The results obtained found its inhibitive effect on the germination and growth of tested species. Though relative germination ratio of the species was somewhat lower than the control plot, severe inhibition was observed in relative dry weight ration, These results were more obvious in aqueous extracts than in the case of leachates and similar results were also confirmed by field bioassays on the forest soil of P. rigida. Therefore, to find out the inhibitory sybstancesm 14 different kinds of KDICical substances were isolatd from the leaved of the tree by chromato-graphy and nist if them were confirmed to be phenoic compounds, The growth of lettuce was inhibition was observed in the concentration of less than 5X10-3M soluton. Phenolic compounds are assumed the substance related to the allelopathic effect of P. rigida.

• The Korean Journal of Ecology
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• v.25 no.6
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• pp.395-398
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• 2002

Present paper showed allelopahtic effects of Tagetes minuta aqueous extracts on seed germination and root hair development. Allelopathy of aqueous extracts derived from T. minuta examined using two test plant species (Lotus comiculatus var. japonicus and Lactuca sativa). The seeds of test species were inoculated in petri dishes containing 0, 10,50 and 100% aqueous extracts from T. minuta. At day 5, the relative seed germination ratio to control was evaluated, and the development of seedling root hairs was observed through light microscopy. Seed germination of L. comiculatus var. japonicus was significantly inhibited proportional to the concentrations of aqueous extract, but that of L. sativa wasn't inhibited. The inhibitory allelopathic effect of T. minuta was found in the development and growth of seedling root hairs. It was concluded that the inhibitory allelophatic effects have been to be investigated using various bioassay, for the allelopathy of plant species shows species-specific and organ-specific.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.279-282
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• 2002

Oryzalexine A, a potent growth inhibitor against several weeds such as Digitaria sanguinalis (L) Scop., and Amaranthus lividus L. was purified by conventional solvent partitioning and column chromatographies. This substance showed strong inhibitory activity on several weeds: Germination of seeds of Poa annua L. was inhibited by 36.5 % at 1.0 mM and Amaranthus lividus L. by 56.1% at 2.5mM. Growth of root and shoot of Digitaria sanguinalis (L.) Scop. by 10.2% and 22.4% at 2.5mM, respectively. These suggest that Oryzalexine A in rice straw might affect the germination and growth of susceptible weeds and other plants.

• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.92-98
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• 2001

Allelopathic effects of the cork tree (Phellodendron amurense Rupr.) on several crops and soil miro-organisms were assessed using germination bioassay and antimicrobial assay, and allelochemicals were identified. In a germination bioassay, extract of cork tree inhibited at high concentration on germination of several crop seeds such as cabbage, lettuce, and cucumber. However, aqueous extracts inhibited powerfully growth of test organisms such as Streptococus aureus, S. aureus, S. typhimurium, and E. coli as bacteria, and Candida albicans as yeast, and Botrytis cineria and Alternata alternaria as fungi.. The cork tree extract showed strong antimicrobial activities against isolated soil fungi. The allelochemicals were separated using Silica gel, Sephadex LH-20 gel column chromatography and HPLC. The substances were analyzed by UV spectrometry and EI-mass spectrometry. The active allelochemicals were identified as isoquinoline alkaloids, berberine and palmatine.

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.142.1-142
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• 1999

No Abstract, See Full Text

• 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 Organic Agriculture
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• v.6 no.2
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• pp.127-140
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• 1998

Organic farming excludes any use of the herbicide. The present paper reviews what can be done for effective weed control with existing weed control technology by farmers crop-ping paddy rice, field crops, vegetables, and fruit trees. If condition of the crop-land-al-lows diversified rotational use of the paddy land as paddy and upland field would minimize weed problem. Practising this is limited in acreage due to extremely limited governmental investment to the land for the purpose. Secondly, rotation of crops in the upland field breaking life cycles of various weeds adapted to each crop should reduce the weed problem. This is also limited as only a few crops are making the farmer profitable. In addition climate and tolerance of crops to high and low temperature. Monsoon rains and poor drainage restrict the freedom of choice. For any crop land year-round multiple cropping in denser planting shall lessen the weed problem, this multiple cropping practiced by 1960s has been abandoned due to laborshortage and increased production cost. Deep flooding the rice is impractical at present in Korean. Mulching crop with transparent, black , or combinated polyethylene sheet, hs been in-creasingly used. Progresses in development and use of mulch with allelopathic crop residues. inexpensive paper mulch, allelopathic crop residues, inexpensive paper mulch, allelopathic crop cultivar development, recently developed ex-perimental weeding machinaries, flamers, microbial herbicides, biological control organisms, soil sterilization techniques have been critically reviewed for their adoption into existing in-tegrated weeding system. Unfortunately, information on cost-benifit, and labor-benefit, for the various methods above mentioned are lacking. Urgent need for the research on rational weeding in organic farming, and herbicide low-input farming is emphasized.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.348-355
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• 1998

This study was conducted to identify allelopathic compounds in rye and oat straw extracts by HPLC analysis. These extracts were analyzed with 12 standard chemicals including salicylic acid. 11 chemicals in rye extract except for naringin and in oat extract except for catechin were identified. Salicylic acid(8.34mg/g) in rye straw extracts and naringin(7.50mg/g) in oat straw extracts among these standard chemicals were identified as the largest amount substance. The germination of Chenopodium ablum seeds was significantly inhibited by these chemicals at $10^{-3}$ and $10^{-4}M$ concentrations as compared to control. Salicylic acid in rye and naringin in oat were considered as the major allelopathic substances although allelopathy may be caused by an interaction of many substances. Yet many unidentified chemical compounds are present in both extracts.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.11-22
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• 1994

The understory vegetation of a Chamaecyparis obtusa plantation is relatively sparse at a valley in Sangkwan-my6n, Wanju-gun, Chiinbuk, Korea, and that of the pure C. obtusa plantation is more sparse than in the C, obtusa-Larix leptolepis plantation. In order to investigate the causes of this difference, this study was carried out both in the field and in the laboratory. Total of 109 taxa, comprising 90 genera and 53 families, were identified in the plantation. But the average number of species above 10% frequency was only 27, and both the number of species and plants per quadrat in the pure C. obtusa plantation were lower than those in the C, obtusa-L. leptolepis plantation. Light intensity, soil pH, and the difference of soil minerals were supposed to be parts of the causes. Soils, litter extracts of C. obtusa and L. leptolepis, and leachates collected by vermiculite beneath C. obtusa canopy for 1 year were tested for the effect on germination and seedling growth of both inside species and outside species in the laboratory. Germination and seedling growth of outside species were more suppressed than those of inside species. Therefore it was found that allelopathic effect of C. obtusa would be responsible for the sparse understory vegetation in the C. oblusa plantation.

• Journal of Korean Society of Forest Science
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• v.84 no.3
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• pp.394-405
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• 1995

Certain ericaceous understory plants of temperate forests proliferate following forest clearcutting and fire. Rapid vegetative growth of these plants may affect conifer regeneration due to their strong competitive abilities and allelopathic properties. Planted conifers in these shrub-dominated habitats experience "growth check" which may result in a loss of productivity or in extreme cases total failure of forest regeneration. This growth check phenomenon is exemplified in Calluna Sitca spruce Scots pine ecosystems of western Europe, Kalmia black spruce ecosystem of eastern Canada and Gaultheria-cedar/hemlock ecosystem of the Pacific Northwest of the United States. Dynamics of Kalmia black spruce ecosystem following disturbance was used to explain the mechanism of conifer growth inhibition and their regeneration failure. It is argued that in addition to competition for nutrients, Kalmia allelopathy plays a major role in growth inhibition of black spruce. This conclusion is supported by the results of various field, laboratory and greenhouse experiments. Eight phenolic compounds were isolated and identified from the leaves of Kalmia angustifolia, four of which are known to be highly phyotoxic to black spruce. Methods of overcoming the allelopathic effects of Kalmia in order to enhance black spruce regeneration in Kalmia-dominated sites are discussed.