• Journal of Applied Biological Chemistry
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• v.59 no.2
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• pp.159-164
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• 2016

Plant growth regulator is an essential pesticide to date while the available active ingredient is not well understood unlike fungicide, insecticide and herbicide. This study was aimed to evaluate a new chemical class of plant growth regulator, and the total of 92 benzene derivatives were screened for their germination and early stage of the root growth regulation on Brassica campestris. Thirty benzaldehydes, nine acids, one amide, and one ester showed potent root growth inhibitory activity (>70 % inhibition) while only salicylaldehyde showed potent germination inhibition ($IC_{50}=81.2mg/L$) suggesting that benzaldehyde was a key module candidate for the growth inhibition. Benzaldehydes were further evaluated for root growth inhibition. 2,3-Dihydroxybenzaldehyde and salicylaldehyde showed $IC_{50}$ values of 8.0 and 83.9 mg/L, respectively. On the other hand, salicylaldehyde, and 2,4,5-trihydroxybenzaldehyde were found to have root growth promotion effects less than 10 mg/L. This result suggests that the benzaldehyde is a new class candidate for plant growth regulator.

• Korean Journal of Environmental Agriculture
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• v.33 no.3
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• pp.194-197
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• 2014

BACKGROUND: Herbal extracts have been screened for their inhibitory effect of seed germination and root development on weeds, but there is a scarcity of reports for crop growth regulation. The objective of this research was to develop a growth inhibitor on Brassica campestris, and its effective extraction method from herbal medicine extract. METHODS AND RESULTS: Eighty four herbal medicine extracts were tested for their plant growth inhibition activity on B. campestris. The alcohol extracts of Artemisia annua, Cinnamomum cassia, and Mentha arvensis inhibited over 30% of germination and the extract of A. annua, and C. cassia inhibited over 70% of radicle growth at 0.1 % w/w treatment. The partially purified extracts of A. annua, and C. cassia with dichloromethane and hexane showed stronger radicle growth inhibition than the crude extracts on B. campestris. The diethyl ether extract of A. annua showed a similar 50% radicle growth inhibition ($RI_{50}$ = 45 mg/L) to its partially purified extract with dichloromethane or hexane, but the diethyl ether extract of C. cassia showed a worse $RI_{50}$ than the purified extract. CONCLUSION: The alcohol extracts of A. annua, and C. cassia showed potent radicle growth inhibition properties on B. campestris. Diethyl ether proved to be a good solvent for simple extraction from A. annua.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.548-554
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• 2016

Optimal range of soil physical quality to enhance crop productivity or to improve environmental health is still in dispute for the upland soil. We hypothesized that the optimal range might be established by comparing soil physical parameters and their interactions inhibiting crop growth. The parameter identifying optimal range covered favorable conditions of aeration, permeability and root extension. To establish soil physical standard two experiments were conducted as follows; 1) investigating interactions of bulk density and aeration porosity in the laboratory test and 2) determining effects of soil compaction and deep & conventional tillage on physical properties and crop growth in the field test. The crops were Perilla frutescens, Zea mays L., Solanum tuberosum L. and Secale cereael. The saturated hydraulic conductivity, bulk density from the root depth, root growth and stem length were obtained. Higher bulk density showed lower aeration porosity and hydraulic conductivity, and finer texture had lower threshold bulk density at 10% aeration bulk density. Reduced crop growth by subsoil compaction was higher in silt clay loam compared to other textures. Loam soil had better physical improvement in deep rotary tillage plot. Combined with results of the present studies, the soil physical quality was possibly assessed by bulk density index. Threshold subsoil bulk density as the upper value were $1.55Mg\;m^{-3}$ in sandy loam, $1.50Mg\;m^{-3}$ in loam and $1.45Mg\;m^{-3}$ in silty clay loam for optimal soil physical quality in upland.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.134-138
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• 2000

Most parts of alfalfa plant have been reported to contain autotoxic substances that inhibit seed germination and early seedling growth, however, the chemical(s) is not still studied much. Effect of seed leachates of 'Vernal' alfalfa (Medicago sativa L.) was evaluated for inhibition of alfalfa germination and root growth through bioassay. Alfalfa seeds were extracted in 1 L deionized water for 1 h after soaking and the leachates caused to reduce root length of alfalfa significantly as the soaking time increased. Crude seeds at 4 g L$L^{-1}$ exudated autotoxins that reduce significantly root length by 34 % compared to the control, when the seeds soaked in deionized water for 24 h. However, the extracts did not affect final germination as well as speed of germination. Extracts from ground seeds significantly reduced speed of germination (GT 50) and root length. The results indicate that release of autotoxic substances from seeds during seed imbibition was increased with increase of soaking time and seed amount, and that autotoxicity was more occurred in ground seeds than in crude seeds.

• Korean Journal of Medicinal Crop Science
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• v.12 no.5
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• pp.349-354
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• 2004

The extracts of Pinus densiflora sawdust by n hexane, ethyl acetate and methanol solvent were investigated to identify their mycelial growth inhibition against Lentinus edodes. The yields of n hexane soluble fraction, ethyl acetate-soluble fraction, and methanol soluble fraction from P. densiflora sawdust were obtained 1.36%, 2.21% and 4.03% using organic solvent, respectively. The mycelial growth inhibition of L. edodes was the greatest for n hexane extract, ranging from 36.5% to 47.6% at concentrations of 125 ppm to 1,000 ppm, with the values for all concentrations significantly different from one another. After direct extraction of P. densiflora sawdust using n hexane, ethyl acetate and methanol, each extract was separated into three fractions by silica gel column chromatography and then the fractions were isolated on the values of $R_f$ by thin layer chromatography. The mycelial growth inhibition against L. edodes was recognized in the fractions II (33.5%) and III (37.6%) of n hexane extract, the fraction II (21.4%) of ethyl acetate extract and the fraction II (26.4%) of methanol extract. The fractions III of n-hexane extract showed the highest growth inhibition among the nine fractions of the organic solvent extract.

• Food Science and Preservation
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• v.20 no.6
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• pp.834-839
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• 2013

The extraction yield, total phenolics content, antioxidant activity, cancer cell growth inhibition (A549 and MCF 7), and lung cancer cell (A549) viability of red rice and black rice were investigated, to evaluate the functional properties of colored rice. The extraction yields and the total phenolics contents of the rice cultivars were Heugseol > Heugkwang > Hongjinju > Jeogjinju > Ilpum. Also, the DPPH radical scavenging activity of the black rice did not differ from that of the red rice, whereas its activity among its cultivars was Jeogjinju > Heugseol > Heugkwang > Hongjinju > Ilpum. The ABTS antioxidant activity of the black rice (Heugkwang, Heugseol) was greater than that of the red rice. The total phenolics was partly attributed to its high antioxidant. On the other hand, the effect of the red rice on the lung cancer cell (A549) viability was higher than that of the black rice. The breast cancer cell (MCF 7) growth inhibition activity of the black rice did not differ from that of the red rice. Our results indicate that the ABTS antioxidant activity of black rice is better than that of red rice, and the lung cancer cell (A549) viability of red rice is better than that of black rice.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.1-6
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• 2010

Allelopathic activity of rotation crop residues to common weeds and selectivity of crops were studied for developing an alternative weed control strategy in upland organic farming. All rotation crop residues with various ratios suppressed weed growth, but the growth of crop species stimulated a little when those were grown with the mixture of rotation crop residues except a few crop species. Among the rotation crop residues used in this study hairy vetch was the most effective, followed by Chinese milkvetch, barley and rye in suppression of weed growth. The 90:10 (crop:soil, v/v) treatments incorporation rate of crop residues such as hairy vetch and Chinese milkvetch suppressed completely the growth of all weed species tested in this study. The effect of crop residues on suppression of weed growth reduced to 90% when the incorporation rates decreased to 60% [60:40 (crop:soil, v/v). It was noticed that broadleaf weed species were more susceptible to rotation crop residues than grass weed species. In the influence of crop residues on the crop growth, no growth inhibition was found in red pepper, lettuce and perllia at any incorporation rates, but tomato, cucumber and corn were slightly inhibited in a few cases at their highest incorporation levels. This study demonstrated that rotation crop residues especially hairy vetch and Chinese milkvetch have high herbicidal effects against weeds without inhibiting the growth of crop species.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.315-319
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• 2012

This study was conducted to select plant growth regulators effective at ginseng berry set inhibition to help root growth in Korean ginseng (Panax ginseng C. A. Meyer). PGRs (ethephon, gibberellic acid, maleic hydrazide, coumarin) were applied to field grown 5-year-old Korean ginseng between one and two times, before and during bloom in 2009, 2010. The number of treatment was more effective in ginseng berry set inhibition when used two times compared with one time in GA 1,000 ppm, MH (5,000, 10,000 ppm), coumarin (5,000, 10,000 ppm) treatment. According to treatment period of plant growth regulator, ginseng berry set inhibition rate from 20days before flowering date to 5days after blooming was the highest in MH 5000 ppm showing 99.9% and the lowest in GA 100 ppm showing 32.8%. The spray treatments of Ethephon (50, 150 ppm) and MH (5,000, 10,000 ppm) from 20 days before the flowering bloom up to 5 days before, and coumarin (5,000, 10,000 ppm) from 20 days to 6 days and before blooming that induced the inhibitory effect more than 90% after 12 weeks. Considering ginseng berry set inhibition characteristics and treatment period ethephon and coumarin was important about applied period but, MH treatment appeared to effective ginseng berry set inhibition regardless of treatment period.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.175-182
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• 2011

This study was conducted to evaluate the growth inhibition of weeds and selectivity of crop species by hairy vetch residues. The growth of all the weed species was suppressed greater than 90% at the ratio 60 : 40 of hairy vetch residues and no weeds were emerged at 90 : 10 mixture in the greenhouse. It was noticed that broadleaf weed species were more suppressed compared to grass weed species. Growth of weeds was significantly reduced and the inhibition percent was increased with increasing application depths of hairy vetch mixture both in vinylhouse and in field conditions. Among the different application depths of hairy vetch mixture, 0.75 cm depth of application tended to inhibit more, but statistically no significant difference was observed between 0.5 cm and 0.75 cm application depth. The growth of weed species such as Galium spurium, Chenopodium album, Plantago asiatica, and Rumex japonicus was greatly suppressed in the vinylhouse and the growth of G. spurium, R. japonicus and Amaranthus retroflexus was suppressed significantly in the field condition. The growth inhibition of all the above mentioned sensitive weed species was approximately 80% at the application depth of 0.5 cm. Crop growth was not hampered by using the residues of hairy vetch. This study demonstrated that rotation crop residues of hairy vetch contained high allelopathic potential to different weed species without hampering the growth of crop species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.426-435
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• 2020

To determine the damages to waxy corn caused by low temperature weather, we investigated the relationship between the temperature and duration of low temperature treatment and the changes in growth characteristics during the recovery period after the treatments in different growth periods. Growth inhibition started in the low temperature group treated at temperatures below 5℃ for three days. The inhibition ratio (IR) was more than 22% or more in all sample groups. As the treatment duration increased and the Temperature decreased, the growth was more greatly inhibited than that in the control. The IR was the highest at 27% or more in the 2nd leaf stage group treated at below 5℃ for 5 days. The IR was in the order of 2nd leaf stage > 1st leaf stage > coleoptile. The IR during recovery was the highest in the 2nd leaf stage group treated at -3℃ degree for 7 days, nd the values were 82% and 98% for NDVI and Fv/Fm, respectively. Especially, all groups treated at -3℃ showed either no changes or decreases in the growth characteristics. As a result, growth inhibition increased as the temperature decreased, and as the duration of the low temperature increased. The degree of damage was in the order of 2nd leaf stage > 1st leaf stage > coleoptile. All early seedlings stopped growing and withered when exposed to temperatures at or below -3℃ for 3 days or more.