• Journal of Microbiology and Biotechnology
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• 제31권11호
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• pp.1526-1532
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• 2021

Suaeda australis, Phragmites australis, Suaeda maritima, Suaeda glauca Bunge, and Limonium tetragonum in the Seocheon salt marsh on the west coast of the Korean Penincula were sampled in order to identify the endophytes inhabiting the roots. A total of 128 endophytic fungal isolates belonging to 31 different genera were identified using the fungal internal transcribed spacer (ITS) regions and the 5.8S ribosomal RNA gene. Fusarium, Paraconiothyrium and Alternaria were the most commonly isolated genera in the plant root samples. Various diversity indicators were used to assess the diversity of the isolated fungi. Pure cultures containing each of the 128 endophytic fungi, respectively, were tested for the plant growth-promoting abilities of the fungus on Waito-C rice germinals. The culture filtrate of the isolate Lt-1-3-3 significantly increased the growth of shoots compared to the shoots treated with the control. Lt-1-3-3 culture filtrate was analyzed and showed the presence of gibberellins (GA₁ 2.487 ng/ml, GA₃ 2.592 ng/ml, GA₉ 3.998, and GA₂₄ 6.191 ng/ml). The culture filtrate from the Lt-1-3-3 fungal isolate produced greater amounts of GA₉ and GA₂₄ than the wild-type Gibberella fujikuroi, a fungus known to produce large amounts of gibberellins. By the molecular analysis, fungal isolate Lt-1-3-3 was identified as Gibberella intermedia, with 100% similarity.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1189-1198
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• 2021

When performing remote tasks using robots in nuclear power plants, a 3D shape measurement system is advantageous in improving the efficiency of remote operations by easily identifying the current state of the target object for example, size, shape, and distance information. Nuclear power plants have high-radiation and underwater environments therefore the electronic parts that comprise 3D shape measurement systems are prone to degradation and thus cannot be used for a long period of time. Also, given the refraction caused by a medium change in the underwater environment, optical design constraints and calibration methods for them are required. The present study proposed a method for developing an underwater 3D shape measurement system with improved radiation tolerance, which is composed of commercial electric parts and a stereo camera while being capable of easily and readily correcting underwater refraction. In an effort to improve its radiation tolerance, the number of parts that are exposed to a radiation environment was minimized to include only necessary components, such as a line beam laser, a motor to rotate the line beam laser, and a stereo camera. Given that a signal processing circuit and control circuit of the camera is susceptible to radiation, an image sensor and lens of the camera were separated from its main body to improve radiation tolerance. The prototype developed in the present study was made of commercial electric parts, and thus it was possible to improve the overall radiation tolerance at a relatively low cost. Also, it was easy to manufacture because there are few constraints for optical design.

• Journal of People, Plants, and Environment
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• 제23권3호
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• pp.333-345
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• 2020

Background and objective: The purpose of this study was to provide basic data on trees that can be used for planting design and construction for permanently shaded areas by grasping the growth status of trees according to the daylight conditions of the outdoor spaces of apartment complexes. Methods: On the recently completed apartment complexes, daylight conditions were analyzed by using daylight simulations utilizing Solar Access Analysis of Ecotect Analysis. With a criteria for assessment of tree condition, the defect rate of trees planted in permanently shaded areas and green spaces with good daylight conditions was analyzed to suggest trees applicable to permanently shaded areas. The first tree survey was conducted from November 18, 2019 to February 15, 2020, focusing on trees planted in permanently shaded areas, and the second tree survey of all the trees planted on the study sites including permanently shaded areas was conducted from March 16 to March 30, 2020. Results: Evergreen trees which are classified as shade intolerant trees including Pinus densiflora, Thuja occidentalis, and Abies holophylla showed a higher defect rate of trees among the trees planted in permanently shaded areas. Taxus cuspidata, Zelkova serrata, Cornus kousa, Chionanthus retusus and Acer palmatum which are classified as shade tolerant trees and shade moderate tolerance trees seemed to be able to be used in the plant design of permanently shaded areas in apartment complexes because the trees showed good growth and a low tree defect rate. In addition, although it was excluded from the analysis due to a small number of samples, Sorbus commixta and Prunus cerasifera var. atropurpurea also can be used for planting in permanently shaded areas. Conclusion: The daylight simulation technique used to analyze permanent shaded areas in this study can be used as an analysis tool considering the daylight environment at the stages of design and construction, and additional research will be required to analyze tree growth according to daylight conditions through data accumulation and monitoring by managing records throughout the entire life cycle of trees in the process of planting and maintenance.

• Korean Journal of Environmental Biology
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• 제34권4호
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• pp.264-271
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• 2016

The objective of this study was to determine the growth and light utilization efficiency of garden plants in shade area through chlorophyll fluorescence reaction analysis. Ten garden plants was grown for 75 days under 50% and 80% shading conditions. Under shading, $ET2_O/RC$, the fluorescence parameter related to electron-transport in photosystem II, was effectively enhanced. However, the electron transport flux until PSI acceptors per reaction center ($RE1_O/RC$) was reduced. These changes in photochemical parameters evoked a decrease in performance index (PI) and driving force (DF) of electron transport flux. In addition, some photochemical parameters such as $F_V$, $FV/F_O$, $RE1_O/RC$, $ET2_O/RC$, $PI_{TOTAL\;ABS}$, and $DF_{TOTAL\;ABS}$ were found to be important for shade tolerance. Three species (Pachysandra terminalis Siebold & Zucc, Physostegia virginiana L., and Carex maculata Bott) were found to be shade tolerant. Based on these results, shading factor index (SFI) deduced from photochemical parameters is useful for evaluating of shading stress of garden plants.

• Journal of Plant Biotechnology
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• 제38권1호
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• pp.22-29
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• 2011

Although reactive oxygen species (ROS) are inevitable by-products of many redox reactions in eukaryotic cells, they play a crucial role as signaling molecules in many cellular processes for development and defense response to abiotic stresses. The biphasic ROS production which was peaked twice in a first transient phase and a second massive phase was occurred after treatment of abiotic stress such as oxidative stress, high salinity. This biphasic generation of ROS was followed by the biphasic production of stress hormone, ethylene. The mechanism of interactions between ROS and ethylene biosynthesis is studied in tobacco (Nicotiana tabaccum L.) plants under the abiotic stresses. The stress-induced ethylene production was significantly inhibited in RbohD-AS and RbohF-AS, in which antisense expression of NADPH oxidase genes was performed. The accumulation of ROS, which was determined by DAB and DCFH-DA staining, was significantly decreased after abiotic stresses in transgenic plants. The suppression of signaling with ethylene and ROS induced more tolerance in response to abiotic stress. The transgenic plants were more tolerant in MS medium supplemented with salinity stress in contrast with wild-type. Stress-induced cell damage determined by DNA fragmentation was decreased at phase II in those transgenic plants. Therefore, the first burst of ROS is more responsible for making a role as a signaling molecule during stress-induced response. These results suggested that ethylene and ROS act in a positive feedback cycle that results in mutual enhancement of ethylene and ROS production during stress-induced cell death.

• Horticultural Science & Technology
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• 제31권6호
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• pp.748-755
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• 2013

This study was conducted to find a salt tolerance gene in Brassica rapa. In order to meet this objective, we analyzed data from a KBGP-24K oligo chip [BrEMD (Brassica rapa EST and microarray database)] of the B. rapa ssp. pekinensis 'Chiifu' under salt stress (250 mM NaCl). From the B. rapa KBGP-24K microarray chip analysis, 202 salt-responsive unigenes were primarily selected under salt stress. Of these, a gene with unknown function but known full-length sequence was chosen to closely investigate the gene function. The selected gene was named BrSSR (B. rapa salt stress resistance). BrSSR contains a 285 bp open reading frame encoding a putative 94-amino acid protein, and a DUF581 domain. The pSL94 vector was designed to over-express BrSSR, and was used to transform tobacco plants for salt tolerance analysis. T1 transgenic tobacco plants that over-expressed BrSSR were selected by PCR and DNA blot analyses. Quantitative real-time RT PCR revealed that the expression of BrSSR in transgenic tobacco plants increased by approximately 3.8-fold. Similar results were obtained by RNA blot analysis. Phenotypic characteristics analysis showed that transgenic tobacco plants with over-expressed BrSSR were more salt-tolerant than the wild type control under 250 mM NaCl for 5 days. Based on these results, we hypothesized that the over-expression of BrSSR may be closely related to the enhancement of salt tolerance.

• Journal of Plant Biotechnology
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• 제43권4호
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• pp.444-449
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• 2016

Deep rooting, which enables plants to extract water from greater soil depths, is a critical strategy for improving plant survival under water-deficient conditions. However, as it is difficult to observe intact root systems belowground, several techniques have been developed to screen deep- and shallow-rooting phenotypes in rice. Here, we introduce a simple and convenient method for deep- and shallow-rooting phenotyping using a unique combination of sand, soil, and plastic mesh netting. Vandana, a drought-tolerant rice variety, and Dongjin, a Korean japonica rice variety, were used to analyze root phenotypes. No significant differences in root length were observed in rice grown under irrigated conditions regardless of net position, whereas roots were significantly longer, and ratio of deep root (RDR) values were significantly higher in Vandana rice grown under semi-drought conditions. In summary, this simple and useful method represents a low-cost means of phenotyping the roots of rice and other crops grown in various-sized pots and at multiple plant growth stages.

• Korean Journal of Environment and Ecology
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• 제7권1호
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• pp.1-5
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• 1993

To examine aluminum toxicity on woody plants, aluminum solution and ground water(pH 6.75) were treated on the seeded pot (48$\times$33$\times$9cm) of Pinus thunbergiana, Thuja orientalis and Ligustrum obtusifolium, filled with sand, three times per week, 5mm per time, from April 28, 1993 to June 16. Aluminum solution were prepared 1.0, 2.5 and 5.0mM aluminum potassium sulfate, dilulted with ground water. Growth-related characters(seedling number, seedling height, top, root and total dry weight) were measured and compared among species and treatments. The response of seedling growth-related characters to aluminum solution treatment differed among the species, and the most sensitive species is Ligustrum obtusifolium, and the most tolerant species is Pinus thunbergiana.

• The Plant Pathology Journal
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• 제35권6호
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• pp.684-691
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• 2019

Evolution of adaptive mechanisms to abiotic stress is essential for plant growth and development. Plants adapt to stress conditions by activating the abscisic acid (ABA) signaling pathway. It has been suggested that the ABA receptor, clade A protein phosphatase, SnRK2 type kinase, and SLAC1 anion channel are important components of the ABA signaling pathway. In this study, we report that the shaker type potassium (K⁺) channel, GORK, modulates plant responses to ABA and abiotic stresses. Our results indicate that the full length of PP2CA is needed to interact with the GORK C-terminal region. We identified a loss of function allele in gork that displayed ABA-hyposensitive phenotype. gork and pp2ca mutants showed opposite responses to ABA in seed germination and seedling growth. Additionally, gork mutant was tolerant to the NaCl and mannitol treatments, whereas pp2ca mutant was sensitive to the NaCl and mannitol treatments. Thus, our results indicate that GORK enhances the sensitivity to ABA and negatively regulates the mechanisms involved in high salinity and osmotic stresses via PP2CA-mediated signals.

• Horticultural Science & Technology
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• 제31권2호
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• pp.219-223
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• 2013

DNA markers can determine the genotype of many species. Single nucleotide polymorphism (SNP) detection is difficult without sequencing but it becomes easier with sdCAPS method. Here an experiment was performed for developing molecular markers using two SNPs, CSatpB-SNP and CSycf1-SNP, of chloroplast in cucumber plants. Properly designed primers with nucleotide sequences for restriction enzymes proved success of PCR and efficacy of digestion by the restriction enzymes. Then these markers were used to study the genotyping of cucumber breeding lines and cultivars obtained from various sources in respect of their chilling stress response. We confirmed that a U.S. cucumber line, 'NC76' known to possess a nuclear factor for the chilling tolerance showed the chloroplast genotypes related to chilling tolerance. However all Korean cucumber cultivars tested in this study showed the chloroplast genotypes related to chilling susceptibility. In conclusion, to develop chilling tolerant cucumber, both maternal and a nuclear factors related to chilling tolerance should be transferred from 'NC76' when 'NC76' is used as a female source and other elite lines as recurrent parents.