• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.232-238
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• 2014

We have developed a non-destructive, touch-free method for estimating leaf areas with a structured-light three-dimensional (3D) scanner. When the surfaces of soybean leaves were analyzed with both the 3D scanner and a leaf area meter, the results were linearly related ($R^2=0.90$). The strong correlation ($R^2=0.98$) was calculated between shoot fresh weights and leaf areas when the scanner was employed during growth stages V1 to V4. We also found that leaf areas measured by the scanner could be used to detect changes in growth responses to abiotic stress. Whereas under control conditions the areas increased over time, salt and drought treatments were associated with reductions in those values after 14 d and 12 d, respectively. Based on our findings, we propose that a structured-light 3D scanner can be used to obtain reliable estimates of leaf area and plant biomass.

• Research in Plant Disease
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• v.29 no.2
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• pp.200-203
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• 2023

Climate change has occurred frequently, and it lead to a severe decrease in marketability and productivity. Onion has various functional elements related to antioxidant, antibacterial, anticancer and immune enhancement, the productivity is closely affected by climate conditions. In this study, to environmentally-friendly produce onions even though drought condition, effect of Bacillus aryabhattai H19-1 on the yield, marketability, and functional component of onions was evaluated in a field. When strain H19-1 was drenched, onion production and marketability significantly increased, and the contents of ascorbic acid and carotenoid of harvested onion bulbs also increased. Therefore, B. aryabhattai H19-1 is expected to be effective in enhancing onion productivity by mitigating drought stress.

• Korean Journal of Plant Resources
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• v.30 no.5
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• pp.571-577
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• 2017

Abscisic acid (ABA) is an important phytohormone involved in abiotic stress tolerance in plants. The group A bZIP transcription factors play important roles in the ABA signaling pathway in Arabidopsis but little is known about their functions in rice. In our current study, we have isolated and characterized a group A bZIP transcription factor in rice, OsABF3 (Oryza sativa ABA responsive element binding factor 3). We examined the expression patterns of OsABF3 in various tissues and time course analysis after abiotic stress treatments such as drought, salinity, cold, oxidative stress, and ABA in rice. Subcellular localization analysis in maize protoplasts using a GFP fusion vector further indicated that OsABF3 is a nuclear protein. Moreover, in a yeast one-hybrid experiment, OsABF3 was shown to bind to ABA responsive elements (ABREs) and its N-terminal region found to be necessary to transactivate a downstream reporter. A homozygous T-DNA insertional mutant of OsABF3 is more sensitive to salinity, drought, and oxidative stress compared with wild type plants ＆ OsABF3OX plants. In addition, this Osabf3 mutant showed a significantly decreased sensitivity to high levels of ABA at germination and post-germination. Collectively, our present results indicate that OsABF3 functions as a transcriptional regulator that modulates the expression of abiotic stress-responsive genes through an ABA-dependent pathway.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.241-248
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• 2017

Yield of potato is largely influenced by drought stress. This study was conducted in Gangneung and Cheongju during the spring cropping of potato. Potatoes in the Gangneung area were affected by drought but there was no damage due to drought in Cheongju. During the early-growth stage, the contents of inorganic components like available phosphate and growth characteristics of the potato leaf in Cheongju were significantly higher than those in Gangneung but there was no difference after the flowering stage. It was considered that the potato plants cultivated in Cheongju could vigorously grow than that of Gangneung under drought stress. In addition, the content of calcium (Ca), which is a secondary messenger related to aging, was found to be higher in potato plants grown in Cheongju than in Gangneung and accumulated more quickly in potato plants of Cheongju. Because magnesium (Mg) was also found to be higher in potato plants from Gangneung by a wide margin, this phenomenon was thought be related with drought stress. The amounts of all inorganic components absorbed from soil were higher in Cheongju than in Gangneung, showing a relatively higher plant biomass in Cheongju. Correlations of development indexes related to leaf showed less or no relation in Gangneung. According to yield characteristics of the harvest stage, although yield was greatly reduced under drought stress condition, the rate of commercial yield was not significantly affected under the drought stress condition. Consequently, it was considered that these responses to drought stress could be utilized to stabilize potato production under the stressful conditions associated with abnormal climate.

• Korean Journal of Remote Sensing
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• v.38 no.2
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• pp.179-188
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• 2022

Global warming causes climate change and increases extreme weather events worldwide, and the occurrence of heatwaves and droughts is also increasing in Korea. For the monitoring of extreme weather, various satellite data such as LST (Land Surface Temperature), TCI (Temperature Condition Index), NDVI (Normalized Difference Vegetation Index), VCI (Vegetation Condition Index), and VHI (Vegetation Health Index) have been used. VHI, the combination of TCI and VCI, represents the vegetation stress affected by meteorological factors like precipitation and temperature and is frequently used to assess droughts under climate change. TCI and VCI require historical reference values for the LST and NDVI for each date and location. So, it is complicated to produce the VHI from the recent satellite GK2A (Geostationary Korea Multi-Purpose Satellite-2A). This study examined the retrieval of VHI using GK2A AMI (Advanced Meteorological Imager) by referencing the historical data from VIIRS (Visible Infrared Imaging Radiometer Suite) NDVI and LST as a proxy data. We found a close relationship between GK2A and VIIRS data needed for the retrieval of VHI. We produced the TCI, VCI, and VHI for GK2A during 2020-2021 at intervals of 8 days and carried out the interpretations of recent extreme weather events in Korea. GK2A VHI could express the changes in vegetation stress in 2020 due to various extreme weather events such as heatwaves (in March and June) and low temperatures (in April and July), and heavy rainfall (in August), while NOAA (National Oceanic and Atmospheric Administration) VHI could not well represent such characteristics. The GK2A VHI presented in this study can be utilized to monitor the vegetation stress due to heatwaves and droughts if the historical reference values of LST and NDVI can be adjusted in a more statistically significant way in the future work.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.41-41
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• 2017

본 연구는 초분광 영상을 이용하여 수박 모종의 수분함량을 비파괴적으로 추정하기 위해 수행되었다. 단계적으로 수분 스트레스를 받은 수박(n=45) 모종을 초분광 영상시스템으로 촬영하여 모종 영역의 반사율을 추출하였고, 매 촬영 후 모종의 생체중과 건물중을 측정하여 수분함량을 계산하였다. 모종의 반사율과 계측된 수분함량을 변수로 하여 Partial Least Square Regression(PLSR) 분석을 이용하여 수분 추정 모델을 구축하였다. 수분 추정모델을 작성한 결과 Calibration(Cal.)의 정확도($R^2$)는 0.66, 정밀도(RMSE 및 RE)는 각각 1.06%, 1.14%로 나타났다. 수박 모종의 수분함량 추정모델의 정밀도는 상당히 높게 나타났으나 정확도는 낮게 나타났다. 정확도를 개선하기 위해 Confidence ellipses의 신뢰구간을 95%로 설정하였을 때 3개의 모종이 타원 밖에 위치하는 것을 발견하였으며 이를 제거 후 재분석을 하였다. 3개의 모종을 제외한 수박 모종의 수분함량 추정모델의 정확도는 0.82, 정밀도는 0.73%, 0.78%로 나타났다. 3개의 모종을 제외함으로서 모델의 정확도 및 정밀도가 상승하여 3개의 모종이 정확도 및 정밀도를 낮추는 원인이라 판단된다. 작물은 가뭄스트레스를 받을수록 반사율이 낮아지지만(Yang et al., 2010) 3개의 모종은 다른 모종의 수분함량에 비해 반사율이 큰 차이를 나타내어 정확도 및 정밀도를 낮춘 것으로 판단된다. 본 연구를 통해 초분광 영상을 이용하여 수박 모종의 수분함량 추정가능성을 시사하였고, 모델의 정확도를 개선하기 위해 샘플 수 및 수분함량의 변이를 증가시키는 것이 필요하다고 판단된다.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.266-274
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• 2010

This study aim to investigate fundamentally the growth and physiological responses of tomato plants in responses to two different levels of water deficit, a weak drought stress (-25 kPa) and a severe drought stress (-100 kPa) in soil. The two levels of water deficit were maintained using a micro-irrigation system consisted of soil sensors for the real-time monitoring of soil water content and irrigation modules in a greenhouse experiment. Soil water contents were fluctuated throughout the 30 days treatment period but differed between the two treatments with the average -47 kPa in -25 kPa set treatment and the -119 kPa in -100 kPa set treatment. There were significant differences in plant height between the two different soil water statuses in plant height without differences of the number of nodes. The plants grown in the severe water-deficit treatment had greater accumulation of biomass than the plants in the weak water-deficit treatment. The severe water-deficit treatment (-119 kPa) also induced greater leaf area and leaf dry weight of the plants than the weak water-deficit treatment did, even though there was no difference in leaf area per unit dry weight. These results of growth parameters tested in this study indicate that the severe drought could cause an adaptation of tomato plants to the drought stress with the enhancement of biomass and leaf expansion without changes of leaf thickness. Greater relative water content of leaves and lower osmotic potential of sap expressed from turgid leaves were recorded in the severe water deficit treatment than in the weak water deficit treatment. This finding also postulated physiological adaptation to be better water status under drought stress. The drought imposition affected significantly on photosynthesis, water use efficiency and stomatal conductance of tomato plants. The severe water-deficit treatment increased PSII activities and water use efficiency, but decreased stomatal conductance than the weak water-deficit treatment. However, there were no differences between the two treatments in total photosynthetic capacity. Finally, there were no differences in the number and biomass of fruits. These results suggested that tomato plants have an ability to make adaptation to water deficit conditions through changes in leaf morphology, osmotic potentials, and water use efficiency as well as PSII activity. These adaptation responses should be considered in the screening of drought tolerance of tomato plants.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.820-828
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• 2015

This study was carried out to determine the effects of vernalization, temperature, and soil water deficit (SD) on mesophyll cells, growth, and yield of Chinese cabbage (Brassica campestris L). The palisade parenchyma and spongy tissues of Chinese cabbage were observed under full irrigation and two weeks of SD treatment. These cells were severely collapsed by four weeks SD treatment. The SD treatment had the greatest influence on the growth of Chinese cabbage among the tested treatment factors (vernalization, temperature, and SD), growth significantly decreased by severe drought treatment (four weeks SD treatment). In addition, the relative growth rate, unit leaf rate, leaf area ratio, specific leaf area, and leaf weight ratio were significantly affected by SD treatment; however, other individual factors and their combined treatments did not influence the analyzed growth parameters. The yield under vernalization after high temperature and full irrigation treatments was 3,056 kg/10 a, which was the greatest among all the tested treatments, while four-week SD treatment significantly reduced the yield. Head formation of Chinese cabbage was not altered under SD treatment, and vernalization treatments did not induce bolting. Our results indicated that collapsing mesophyll cells and reduced growth and yield were induced by SD treatment. Thus we suggest that optimal irrigation system should be install to avoid or overcome crippling drought conditions in the open field.

• Journal of Life Science
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• v.28 no.10
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• pp.1132-1139
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• 2018

The stability of diverse cellular proteins in eukaryotes is regulated via ubiquitination. Moreover, E3 ligase plays a crucial role in determining substrate specificity and transfers ubiquitins into the substrates during the ubiquitination process. As a type of multi-subunit E3 ligase, cullin4 (CUL4)-based E3 ligase (CRL4) complex is involved in a variety of cellular processes, such as hormonal and stress responses in plants. In spite of several reports on the versatile roles of CRL4 in various signalings in Arabidopsis, CRL4's function in rice has been poorly known. To learn about CRL4-mediated cellular processes in rice in more detail, OsCUL4 that exhibits the highest homology with Arabidopsis CUL4 was isolated, and its expression patterns in various tissues and in response to plant hormones and abiotic stresses were monitored. Exogenous application of ABA or cytokinin increased the transcript levels of the OsCUL4 gene. Moreover, OsCUL4 was significantly upregulated in response to drought and salt stresses. These findings imply that OsCUL4 may be functionally related to ABA- and/or cytokinin-mediated cellular responses. OsCUL4 directly interacted with OsDDB1, an adaptor protein of CRL4, indicating that OsCUL4 can act as a scaffold protein of CRL4. An expression study on the OsCUL4 gene from this report could be used as a starting point to elucidate cellular responses in which a CRL4-mediated ubiquitination process is involved in rice.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.31-38
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• 2017

This study was carried out to investigate the possibility of isolating the useful gene of soybean plant, anthocyanin, through NGS (Next Generation Sequencing) and molecular biology experiments. Lespedeza cuneata. G. don is a resource plant but has many useful materials. Especially, D-pinitol, which has anti-diabetic function, is contained in a large amount. However, the gene related to the biosynthesis of D-piniol has not been isolated in the non-spermatid. Lespedeza cuneata. G. don was treated with abiotic stress (drought), total RNA was extracted, and a library was constructed to perform NGS. In this way, the genes involved in D-pinitol biosynthesis were isolated and sequenced in silico. In order to support this, ononitol epimerase involved in D-pinitol amplification was identified using the Blast program and RT-PCR confirmed the increased gene expression in vitro, and the gene was isolated and identified by convergence study.