• Korean Journal of Environmental Agriculture
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• 제29권2호
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• pp.109-114
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• 2010

Rape residue as green manure is an emerging alternative of chemical fertilizer to improve soil quality and crop productivity. Objective of this research was to evaluate the effectiveness of rape residue as green manure on reduction of chemical fertilizer and suppression of weed occurrence in rice-rape double cropping system. Greenhouse experiment was conducted with four treatments: the combination of rape residue and three different N application rates (0, 30 and 70% of recommended application rate (7.8 kg N $10a^{-1}$)) and 100% chemical fertilizer as a control. No difference in rice clum length was observed for all treatments, while panicle length was highest in a treatment of rape residue+70% chemical fertilizer (Rape+70%CF). In addition, rice grain weight at a Rape+70%CF treatment increased by 19% compared to the control. This treatment also reduced weed density and biomass by 58 and 53%, respectively, compared to the control. Our results suggest that use of rape residues as green manure is an environment friendly and effective way to reduce chemical fertilizer and to enhance crop productivity in rice-rape double cropping system in Korea.

• Microbiology and Biotechnology Letters
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• 제39권2호
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• pp.104-110
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• 2011

Actinomycetes, Gram positive soil bacteria, are valuable microorganisms which produce useful secondary metabolites including antibiotics, antiparasitic substances, anti-cancer drugs, and immunosuppressants. Although a major family of actinomycetes, known as streptomycetes, has been intensively investigated at the molecular level for several decades, a potentially valuable and only recently isolated non-streptomycetes rare actinomycetes (NSRA) family has been poorly characterized due to lack of proper genetic manipulation systems. Here we report that a PCR-based genome screening strategy was performed with approximately 180 independently isolated actinomycetes strains to isolate potentially valuable NSRA strains. Thanks to this simple PCR-based genome screening strategy we were able to identify only seven NSRA strains, followed by 16S rRNA sequencing for confirmation. Through further bioassays, one potentially valuable NSRA strain (tentatively named Nocardiopsis species MMBL010) was identified which possessed both antifungal and antibacterial activities, along with the presence of polyketide synthase and non-ribosomal peptide synthase genes. Moreover, Nocardiopsis species MMBL010, which was intrinsically recalcitrant to genetic manipulation, was successfully transformed via E. coli-driven conjugation. These results suggest that PCR-based genome screening, followed by the establishment of an E. coli-driven conjugation system, is an efficient strategy to maximize potentially valuable compounds and their biosynthetic genes from NSRA strains isolated from various environments.

• Journal of the Korean Geophysical Society
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• 제6권3호
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• pp.189-207
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• 2003

The purpose of this paper is to analyze the behavior and to study the safety evaluation of the Unmun Dam located in Cheongdo-Gun of GyeongBuk Province, Korea. For this purpose, soil analyses including boring data, geophysical surveys and monitoring the buried geotechnical gauges, such as pore-pressure gauge, earth-pressure gauge, displacement gauge, multi-layer settlement gauge, leakage flow-meter, were conducted. In addition to these data, numerical analyses of behavior of dam were performed to predict and to compare the data which were obtained from the above methods. Since many defects, such as gravel and weathered rock blocks in the dam core, and lots of amounts of leakage, by boring analyses were found, reinforcement by compaction grouting system (CGS) has been conducted in some range of dam. Some geotechnical gauge data were also used to confirm the effects of reinforcement. Analyses of monitoring the data of geotechnical gauges buried in the dam, such as pore-pressure gauge, earth-pressure gauge, displacement gauge, multi-layer settlement gauge, and leakage flow-meter shows the load transfer of dam and the possibility of hydraulic fracturing. As a conclusion, some problems in the dam found. Especially, the dam near spillway shows the high possibility of leakage. It should be pointed out that only the left side of he dam has not a leakage problem. As a whole, the dam has problems of weakness, because of unsatisfactory construction. It is strongly recommended that highly intensive monitoring is required.

• Korean Journal of Plant Resources
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• 제21권2호
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• pp.111-116
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• 2008

This study was carried out to induce plant regeneration via multiple shoot formation from sucker explants of Rubus fruticosus L. ${\times}$ R. parvifolius L. To induce adventitious shoots, the sucker explants were sterilized in 1.2% sodium hypochlorite (NaOCl) solution, and then were cultured on the full and 1/2 MS solid medium supplemented with BA (0.1, 0.5, 1.0, $2.0mg{\cdot}L^{-1}$). After 4 weeks of culture, the highest frequency (83.3%) of shoot formation from sucker explants was obtained from the full MS medium with $1.0mg{\cdot}L^{-1}$ BA. The highest shoot number (3.7) per explant was obtained from the full MS medium with $0.5mg{\cdot}L^{-1}$ BA. After 12 weeks of culture, the number of shoots (15.4) per explant was increased. The highest frequency (95%) of root formation was obtained from the 1/2 MS medium, when the explant with shoot were cultured on the full, 1/2 and 1/4 MS medium. The survival rate of the plantlets after transfer to plastic pots containing sand, soil, and vermiculite (1.1:1, vol.) was 95%. The results indicate that multiple shoot procedure can be applied for an efficient mass propagation of Rubus fruticosus L. ${\times}$ R. parvifolius L.

• Journal of Forest and Environmental Science
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• 제36권3호
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• pp.207-218
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• 2020

Ashwagandha is an important ancient medicinal crops, being affected with many diseases, among which leaf blight caused by Alternaria alternata has become the constraint resulting in huge yield losses. Continuous usage of chemical methods leads to environment, soil and water pollution. Whereas biological control of diseases is long lasting, inexpensive, eco-friendly and harmless to target organisms. In this context, it is aimed to evaluate five Trichoderma strains viz. Trichoderma virens IMI-392430, T. pseudokoningii IMI-392431, T. harzianum IMI-392432, T. harzianum IMI-392433 and T. harzianum IMI-392434 as bio-control efficacy against A. alternata and growth promoting effect in Ashwagandha. All the Trichoderma strains had varied antagonistic effects against the pathogen. In dual culture technique, the strain T. harzianum IMI-392433 showed maximum percentage inhibition of mycelial growth (54.89%) followed by T. harzianum IMI-392432 (53.83%), T. harzianum IMI-392434 (48.94%) and T. virens IMI-392430, (43.62%) against the pathogen, while the least inhibition percentage was observed with the T. pseudokoningii IMI-392431 (36.60%). The culture filtrate of the Trichoderma strain, T. harzianum IMI-392433 recorded highest inhibition on the mycelial growth (39.05%) and spore germination (80.77%) of pathogen and the lowest was recorded in T. pseudokoningii IMI-392431 (20.45 and 50%). Moreover, seeds treated with spore suspension of the strain T. harzianum IMI-392433 reduced the percentages of disease severity index significantly. The strain T. harzianum IMI-392433 also significantly increased seed germination %, seedling vigor and growth of Ashwagandha. The correlation matrix showed that root yield per plant of Ashwagandha had significant and positive correlation with plant height (r=0.726^⁎⁎), number of leaf (r=0.514^⁎⁎), number of primary branch (r=0.820^⁎⁎), number of secondary branch (r=0.829^⁎⁎), fresh plant weight (r=0.887^⁎⁎), plant dry weight (r=0.613^⁎⁎), root length (r=0.824^⁎⁎), root diameter (r=0.786^⁎⁎), root dry weight (r=0.739^⁎⁎) and fresh root weight (r=0.731^⁎⁎). The significant and negative correlation (r=-0.336^⁎⁎) was observed with the root yield and percentages of disease severity index. The study recognized that the T. harzianum IMI-392433 strain performed well in inhibiting the mycelial growth and reduced the percentages of disease severity index of pathogen as well as increased the plant growth in Ashwagandha.

• Journal of the Korean Geotechnical Society
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• 제19권6호
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• pp.387-395
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• 2003

Model tests were conducted to study the behavior of the piled raft foundation system on sands. Especially in this study, the method using the triaxial compression apparatus was devised and used to apply the confining pressure which is considered difficult in the existing model test on the soil. Steel rods (6mm dia.) and aluminum plates (8mm thickness, 50mm dia.) were used to simulate piles and rafts respectively. Jumunjin standard sands were used to ensure the homogeneity of the sample. After the sample with the piled raft model was laid inside the triaxial cell, the confining pressure was applied and then the compressive force was applied. The increase and/or decrease ratio of the bearing capacity, the load distribution ratio between raft and piles and the effect of settlements decrease depending on the confining pressure, the number of piles and the length of piles were analyzed and the bearing capacity and skin friction of the pile was calculated. By the results of these experiments, the bearing capacity increased and the settlement decreased with this piled raft foundation system. Especially the effect was larger with the increase of the number of piles than with the increase of length of piles. Hereafter, the study of the load transfer mechanism of piles under confining pressure would be made possible using these small model tester like triaxial compression apparatus.

• Journal of Plant Biotechnology
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• 제34권1호
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• pp.11-17
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• 2007

Previously developed transgenic watermelon rootstocks (gongdae) inserted by CGMMV-CP were examined to test the virus tolerance levels. In the restricted plastic house, the $T_{3}$ watermelon rootstock showed tolerance to CGMMV until 70 days after inoculation on the leaves while the non-transformed watermelon rootstock became susceptible at 20 days after inoculation. In the field, tolerance efficiency of transgenic rootstocks maintained up to 40% at 71 days after contamination with CGMMV in the soil while all of the non-transformed rootstocks became susceptible at 37 days with the same condition. In the same field, transgenic rootstocks showed more tolerance to CGMMV than the non-transformed rootstocks as those were inoculated on the leaves, but it showed only 10 days delay before being susceptible. Therefore, transgenic rootstocks have a characteristic of delay effect against CGMMV susceptibility, rather than resistance character. From $T_{3}$ rootstocks homozygous for the CGMMV-CP horticulturally favorable individuals were selected for further breeding and a transgenic line was finally obtained at the $BC_{1}T_{5}$. A material transfer experiment was conducted to find out if the DNA, RNA or expressed protein in the transgenic rootstocks could move to the grafted scion (non-transformed watermelon, Super-Kumcheon). PCR, northern, and western blot analysis were performed and no evidence of transferring of those materials from rootstock to scion was ever found.

• Journal of Plant Biotechnology
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• 제34권1호
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• pp.25-29
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• 2007

Plant regeneration system from zygotic embryos (2n=24) of Lilium lancifolium Thunb. via bulblet formation was estabished. Zygotic embryos of Lilium lancifolium formed bulblets and somatic embryos simultaneously when they cultured on MS medium supplemented with low concentration of 2,4-D. The highest frequency of bulblet and somatic embryo formation from zygotic embryos of Lilium lancifolium was 66.7% and 56.7%, respectively. The frequency of bulblet and somatic embryo formation was decreased when they cultured on MS medium over than 1 mg/L of 2,4-D. To regenerate whole plants, somatic embryos formed on zygotic embryos were transferred to MS basal medium. However somatic embryos did not fully converted into plantlets. Further incubation in the light, elongated somatic embryos formed numerous bulblets at the base of somatic embryos. Upon transfer to MS basal medium, bulblets were successfully converted into plantlets after further 4 weeks of culture in the light. After acclimatization, plantets from bulblets were transferred to soil and grown to normal plants in growth chamber (approximately $30\;{\mu}mol\;m^{-2}s^{-1}$, 16/8h photo period, $25^{\circ}C$) The chromosome analysis revealed that plants regenerated from zygotic embryos showed 2n=24. These results indicate that chromosome stability of source tissue is maintained during plant regeneration via bulblet formation.

• Korean Journal of Plant Resources
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• 제18권3호
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• pp.456-461
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• 2005

This study was carried out to induce plant regeneration via shoot formation from sucker explants of Rubus fruticosus L. To induce adventitious shoots, sucker explants were sterilized in $1.2\%$ NaOCl solution, and cultured on the MS solid medium supplemented with kinetin (0.5, 1.0, 3.0 mg/L) and BA (0.5, 1.0, 3.0 mg/L), respectively. As above, to induce adventitious shoots, sucker explants were cultured on the MS solid medium supplemented with IBA (0, 0.1, 1.0 mg/L) and BA (0, 0.1, 1.0, 2.0 mg/L). After 4 weeks of culture, the highest frquency $(100\%)$ of shoot formation from sucker explants was obtained from the medium with 1.0 mg/L BA. The highest shoot number per explant from in vitro shoot explants was 5.3. After 10 weeks of culture, the number of shoot per explant was increased. The highest frequency $(85\%)$ of root formation was obtained at 0.5 mg/L glycine medium, when the explant with shoot were cultured on the MS medium containing glycine at various concentrations from 0 to 2.0 mg/L. The survival rate of the plantlets after transfer to plastic pots containing sand, soil, and vermiculite (1:1:1, vol.) was $95\%$. The results indicate that micropropagation procedure can be applied for an efficient mass propagation of Rubus fruticosus.

• Korean Journal of Plant Tissue Culture
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• 제21권3호
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• pp.157-160
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• 1994

Culture conditions for high Sequency somatic embryogenesis and plant regeneration in tissue cultures of sweet potato of two Korean cultivars 'Puyojaerae' and 'Yulmi' are described. Shoot apical meristem explants (height 150 $\mu\textrm{m}$; base: 350 $\mu\textrm{m}$) were cultured on MS medium supplemented with 1 mg/L 2,4-D. After 6 weeks of culture, greater than 80% of the survived explants produced embryogenic calli. When transferred onto MS medium with 0.1 mg/L each of 2,4-D and kinetin, the calli gave rise to somatic embryos at frequencies of 71% ('Puyojaerae') and 63% ('Yulmi'), respectively: When somatic embryos at various developmental stages measured in length were transversely cut into two halves and cultured on MS medium with 1 mg/L 2,L-D, the upper halves produced secondary embryos more frequently than the lower ones, and halves of somatic embryos less than 1 mm in length had a higher competence for secondary embryo formation than longer ones of either cultivar. However 'Puyojaerae' somatic embryo halves showed a higher frequency of secondary embryo formation than 'Yulmi' ones on the whole. Upon transfer onto MS basal medium, most of the primary and secondary somatic embryos underwent development into plantlets. The plantlets were transplanted to potting soil and grown to maturity in a phytotron. The overall results suggest that the shoot apical meristem culture system for somatic embryo formation in sweet potato previously established by us (SABRAOJ 21: 93-101) may be applicable regardless of it genotypes.