• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.377-383
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• 1997

Studies were conducted on the nature of allelopathic effect of the substances in the waste of ginkgo leaves from pharmaceutic factory. In the first step, to find out whether there was any allelophatic effect, young seedlings of radish and rice were grown in the water (crude) extract of ginkgo leaf waste and in different liquid/lquid partitioned fractions of EtOAc at pH 9, EtOAc at pH 3, and BuOH. As second step, attempts were made to isolate and identify the allelophatic substance in different liquid/liquid partitioned fractions using GC/MS and NMR techniques. The water (crude) extract of ginkgo leaf waste retarded the growth of radish seedlings under 10% concentration. In case of rice seedlings, the water extract of ginkgo leaf extract showed adverse effect on the growth when combined with $3.3{\times}10^{-6}M$ gibberellin A3. All of the liquid/liquid fractions of crude extract showed strong retardation of seedling growth of radish and rice at the concentration of 1%. Allelophatic substance was isolated from the crude extract using liquid/liquid partition, column chromatography and HPLC techniques. The analytical results of isolated componet using GC/MS and NMR proved that the allelophatic substance in the ginkgo leaf wastes is catechol; one of phenol compounds. Based on the experiences current study, a practical method for the testing of allelophatic effect of crude extract of some materials was proposed. In this method, rice seeds were allowed to sprout until the length of coleoptile to reach 0.5 mm. Such seedlings were submerged in the solution containing supposedly allelophatic substance and the length of shoot and root was measured 3 days after treatment.

• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.1-6
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• 1999

This study was conducted to detect the allelopathic effect of water and ethanol extracts from 4 plant species (Lactuca sativa L., Ambrosia elatior L., Oenothenra odorata Jasp., Ginkgo biloba L.) on germination and growth of lettuce seeds. A little bit higher inhibitory effect was obtained in ethanol extracts rather than water extracts. Allelopathic effects varied in the source of extracts and concentrations of 4 plant species and the highest allelopathic effect appeared in 10% solution, regardless of plant species.

• Journal of the Korean Applied Science and Technology
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• v.14 no.1
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• pp.61-76
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• 1997

Triacylglycerols of the seeds of Ginkgo biloba have been resolved by high-performace liquid chromatography(HPLC} in the silver-ion and reverse-phase modes. The fatty acids were identified by a combination of capillary gas chromatography and gas-chromatography /mass spectrometry as the methyl and /or picolinyl ester. The main components are $C_{18:2{\omega}6}$(39.0mol%), $C_{18:1{\omega}7}$(asclepic acid 21.5mol%), and $C_{18:1{\omega}9}$(oleic acid, 13.8mol%). Considerable amounts of unusual acid such as $C_{20:3{\Delta}^{5,11,14}$ (5.7mol%), $C_{18:2{\Delta}^{5,9}$(2.8mol%), and $C_{18:3}{\Delta}^{5,9,12}$(1.6mol%), were checked. In addition, an anteiso-branched fatty acid, 14-methylhexadecanoic acid, was also present as a minor component(0.9 mol%). The triacylglycerols were separated into 17 fractions by reverse-phase HPLC, and the fractionation was achieved according to the partition numnber(PN) in which a ${\Delta}^5$-non methylene interrupted double bond($^5$-NMDB) showed different behaviour from a methylene interrupted double bond in a molecule with a given cahinlength. Silver-ion HPLC exhibited excellent resolution in which fractions(23 fractions) were resolved on the basis of the number and configuration of double bonds. In this instance, the strength of interaction of a ${\Delta}^5$-NMDB system with silver ions seemed to be weaker than a methylene interrupted double bond system. The principal triacylglycerol species are as follows ; $(C_{18:2{\omega}6)2}/C_{18:1{\omega}7}$, $C_{18:1{\omega}9}/C_{18:1{\omega}7}/C_{18:2{\omega}6}$, $(C_{18:1{\omega}7)2}/C_{18:2{\omega}6}$, $C_{16:1{\omega}7}/C_{18:1{\omega}9}/C_{20:3}{\Delta}^{5,11,14}$, $C_{16:1{\omega}7}/C_{18:1{\omega}7}/C_{20:3}{\Delta}^{5,11,14}$, $C_{18:1{\omega}9}/C_{18:1{\omega}7}/C_{18:2{\omega}6}$, $C_{18:1{\omega}9}/C_{18:2}{\Delta}^{5,5}/C_{20:3}{\Delta}^{5,11,14}$, $(C_{18:1{\omega}7)2}/C_{18:2{\omega}6}$ and $(C_{18:1{\omega}9)2}/C_{18:2{\omega}6}$, while simple triacylglycerols without $C_{18:2{\omega}6})_3$ were not present. Stereospecific analysis showed that fatty acids with ${\Delta}^5$-NMDB system and saturated chains were predominantly located at the site of sn-3 carbon of glycerol backbones. It is evident that there is asymmetry in the distribution of fatty acids in the TG molecules of Ginkgo nut oils.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.4
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• pp.7-20
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• 2004

This study was executed to find out how to improve the planting and use of landscaping plants in Chuncheon. The number of street trees was 17,877 in 2003. The major species of street trees were Ginkgo biloba(52.7％), Prunus sargentii(15.3％), Zelkova serrata(8.9％), Platanus occidentalis(7.3％). Salix babylonica and Platanus occidentalis were decreased, while Prunus sargentii and Zelkova serrata were increased. Salix babylonica is a good species for a lakeside city, but its seeds cause allergies to some people. Most of the trees have been removed in Chuncheon. The planting of Salix babylonica(♂) resulted in no problems, and it should be propagated to plant. The soil of several areas was analysed to investigate soil conditions. The outskirts of city had good conditions in pH, organic matter and minerals, but the downtown areas had high alkalic, due to alkali from footpath concrete blocks. Appropriate pruning adds to the aesthetic and prolongs the useful life; it also requires less managing of insects and diseases to maintain good healthy of street trees. Street trees were not properly pruned due to electric lines and shortage of pruning information. The pruning was controlled by Korea Electric Power Co, which has no pruning information. Pruning must be maintained by a professional landscape company to maintain good shape such as with Bonsai. The Shrubs planting zone between street trees and other trees, and preservation plates were established for healthy of street trees. They have to be repaired and maintained well to keep better environmental conditions. The number of tree and flower species of 68 schools in Chuncheon were 12 and 16, respectively. The species that showed high preference were Juniperus chinensis, Pinus koraiensis, Pinus densiflora, Rosa centifolia, Forsythia koreana, and Rhododendron schlippenbachii. The high frequency of the protection trees designated by Chuncheon were Pinus densiflora, Ginko biloba, Zelkova serrata, Quercus species. It was thought that the diversification of street tree species, the selection of street trees suitable to each space, the generalization of use of native species, the appropriate pruning and proper fertilization, the control of pests and diseases, and the opinions of citizens concerning landscape plants were needed to improve the planting, use and maintenance of landscaping plants in Chuncheon.