• Korean Journal of Medicinal Crop Science
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• v.26 no.2
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• pp.181-187
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• 2018

Background: This study aimed to investigate out the influence of drought stress on the physiological responses of Dendropanax morbifera seedlings. Methods and Results: Drought stress was induced by discontinuing water supply for 30 days. Under drought stress, photosynthetic activity was significantly reduced with decreasing soil water content (SWC), as revealed by the parameters such as Fv/Fm, maximum photosynthetic rate ($P_{N\;max}$), stomatal conductance ($g_s$), stomatal transpiration rate (E), and intercellular $CO_2$ concentration (Ci). However, water use efficiency (WUE) was increased by 2.5 times because of the decrease in $g_s$ to reduce transpiration. Particularly, E and $g_s$ were remarkably decreased when water was withheld for 21 days at 6.2% of SWC. Dendropanax morbifera leaves showed osmotic adjustment of -0.30 MPa at full turgor and -0.13 MPa at zero turgor. In contrast, the maximum bulk modulus of elasticity ($E_{max}$) did not change significantly. Thus, Dendropanax morbifera seedlings could tolerate drought stress via osmotic adjustment. Conclusions: Drought avoidance mechanisms of D. morbifera involve reduction in water loss from plants, through the control of stomatal transpiration, and reduction in cellular osmotic potential. Notably photosynthetic activity was remarkably reduced, to approximately 6% of the SWC.

• Plant Biotechnology Reports
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• v.5 no.1
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• pp.61-69
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• 2011

The dehydration-responsive element binding proteins (DREB1)/C-repeat (CRT) binding factors (CBF) function as transcription factors and play an important role in agricultural biotechnology and molecular biology studies of drought and freezing stress tolerance. We generated transgenic Lolium perenne plants containing the PCR-cloned Arabidopsis DREB1A/CBF3 gene (AtDREB1A/CBF3) to study the function of this gene construct in drought and freezing tolerance in a species of turfgrass. Compared to the control, AtDREB1A/CBF3 transgenic L. perenne plants showed enhanced drought and freezing stress tolerance. The activities of the enzymes superoxide dismutase (SOD) and peroxidase (POD) were higher in transgenic plants than in the non-transgenic plant control. These results demonstrate that the expression of the AtDREB1A/CBF3 gene in transgenic L. perenne plants enhanced drought and freezing tolerance and that the increased stress tolerance was associated with the increased activities of antioxidant enzymes. These results are relevant to stress biology and biotechnology studies of turfgrass.

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.10a
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• pp.179-179
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• 2018

Potato (Solanum tubersosum L.) is susceptible to various environmental stresses such as salt, high temperature, and drought. Especially, potato tuber growth is greatly affected by drought that causes not only yield reduction but also loss of tuber quality. Since unpredictable global weather changes cause more severe and frequent water limiting conditions, improvement of potato drought tolerance can minimize such adverse effects under drought and can impact on sustainable potato production. Genetic engineering can be utilized to improve potato drought tolerance, but such approaches using endogenous potato genes have rarely been applied. We were obtained AtbZIP28 gene transgenic potato plants. It is identified transcript levels at various stress conditions, polyethylene glycol (PEG), NaCl, (ABA). Also, For identification to regulate ER stress response genes in AtbZIP28 gene transgenic potato plant, we screened seven potato genes from RNA-seq analysis under TM treatment. Five and two genes were up- and down-regulated by TM, respectively. Their expression patterns were re-examined at stress agents known to elicit TM, DTT, DMSO and salt stress.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.121-131
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• 2018

Climate change has caused changes in environmental factors that have a direct impact on agriculture such as temperature and precipitation. The meteorological disaster that has the greatest impact on agriculture is drought, and its forecasts are closely related to agricultural production and water supply. In the case of terrestrial data, the accuracy of the spatial map obtained by interpolating the each point data is lowered because it is based on the point observation. Therefore, acquisition of various meteorological data through satellite imagery can complement this terrestrial based drought monitoring. In this study, Evaporative Stress Index (ESI) was used as satellite data for drought determination. The ESI was developed by NASA and USDA, and is calculated through thermal observations of GOES satellites, MODIS, Landsat 5, 7 and 8. We will identify the difference between ESI and other satellite-based drought assessment indices (Vegetation Health Index, VHI, Leaf Area Index, LAI, Enhanced Vegetation Index, EVI), and use it to analyze the drought in South Korea, and examines the applicability of ESI as a new indicator of agricultural drought monitoring.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.160-160
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• 2017

Drought stress is a major constraint of crop development and productivity. Plants have evolutionally developed several mechanisms at the molecular, cellular, and physiological levels to overcome drought stress. The basic Leucine zipper (bZIP) transcription factor (TF) family members are starting to be concerned about their roles in drought stress responses. In this study, we functionally characterized OsbZIP66, a rice group-E bZIP TF, to be associated with rice drought tolerance mechanisms. Expression of OsbZIP66 was significantly induced upon treatments of rice plants with drought, high salinity, and ABA. These observations and the fact that the OsbZIP66 promoter contains ten ABA-responsive elements suggest that OsbZIP66 is up-regulated by drought stress in an ABA-dependent manner. Overexpression of both OsbZIP66 in a whole plant body and specifically in roots enhanced drought tolerance of rice plants, indicating that the rice drought tolerance positively correlates with the expression levels of OsbZIP66. Thus, our results demonstrated that OsbZIP66 has a potential for use in biotechnological development of high-yielding rice plants under drought conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.95-101
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• 2002

To investigate the changes in the composition and pool size of nitrogen metabolites under drought stress, white clover (Trifolium repens L.) were exposed to -0.04MPa (well-watered, control) or to -0.12MPa (drought-stressed) of soil water potential during 28 days. Dry weight of leaves in drought-stressed plants was remarkably decreased by 45% and 74% within 14 days and 28 days, respectively, compared with control. For nitrate concentration after 28 days of treatment, a significant difference (1.6 times higher in drought-stressed plants) was observed only in stolon. NH$_3$-NH$_4$$^{+}$ concentration in all three organs of drought-stressed plants linearly increased to more than 1.6 times higher level at 28 day when compared to the initial level (day 0), while the increasing rate in control was much less than that of drought-stressed plants. Proline concentrations in drought-stressed plants remarkably increased and reached to 7, 13 and 17 times higher level at 28 day compared to control. Protein concentration in leaves of drought-stressed plants tended to decrease, while it slightly increased during the first 14 days and reached a plateau afterward in control. There was not significant difference in the proteins concentration of stolon and roots throughout experimental period. On SDS-PAGE analysis, two major proteins specifically induced by drought stress (16-kD and 18-kD) were detected in stolon.n.

• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.1-5
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• 2015

Drought is one of the major abiotic constraints limiting quantity and quality of rice grain. In order to elucidate the effects of drought on chemical compositions of rice grain, seedlings were cultivated in a rainout shelter controlled with well-watered or water-deficit conditions. After harvesting, the key components including proximates, amino acids, fatty acids, minerals, and vitamins of rice grains were analyzed. Drought stress increased the amounts of methionine, phenylalanine, linoleic acid, linolenic acid, calcium, potassium, vitamin B1, and vitamin E in rice grains, whereas it decreased the contents of lignoceric acid. Particularly, drought stress caused a marked increase in vitamin E content. These results indicate drought significantly influence the chemical compositions of rice grains.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.575-584
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• 2015

Drought stress is a crucial environmental factor determining crop survival and productivity. The goal of this study was to clearly identify a new drought stress-tolerance gene in Brassica rapa. From KBGP-24K microarray data with the B. rapa ssp. pekinensis inbred line 'Chiifu' under drought stress treatment, a gene which was named BrDSR (B. rapa Drought Stress Resistance) was chosen among 738 drought-responsive unigenes. BrDSR function has yet to be determined, but its expression was induced over 6-fold by drought. To characterize BrDSR, the gene was isolated from B. rapa inbred line 'CT001' and found to contain a 438-bp open reading frame encoding a 145 amino acid protein. The full-length cDNA of BrDSR was used to construct an over-expression vector, 'pSL100'. Tobacco transformation was then conducted to analyze whether the BrDSR gene can increase drought tolerance in plants. The BrDSR expression level in T1 transgenic tobacco plants selected via PCR and DNA blot analyses was up to 2.6-fold higher than non-transgenic tobacco. Analysis of phenotype clearly showed that BrDSR-expressing tobacco plants exhibited more tolerance than wild type under 10 d drought stress. Taking all of these findings together, we expect that BrDSR functions effectively in plant growth and survival of drought stress conditions.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.64-72
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• 2023

Biopolymer is a versatile material used in food processing, medicine, construction, and soil reinforcement. 𝛽-glucan is one of the biopolymers that improves the soil water content and ion adsorption in a drought or toxic metal contaminated land for plant survival. We analyzed drought stress damage reduction in sweet potatoes (Ipomoea batatas L. cv. Sodammi) by measuring the growth and major protein expression and activity under 𝛽-glucan soil amendment. The result showed that sweet potato leaf length and width were not affected by drought stress for 14 days, but sweet potatoes grown in 𝛽-glucan-amended soil showed an effect in preventing wilting caused by drought in phenotypic changes. Under drought stress, sweet potato leaves did not show any changes in electrolyte leakage, but the relative water content was higher in sweet potatoes grown in 𝛽-glucan-amended soil than in normal soil. 𝛽-glucan soil amendment increased the expression of plasma membrane (PM) H⁺-ATPase, but it decreased the aquaporin PIP2 (plasma membrane intrinsic protein 2) in sweet potatoes under drought stress. Moreover, water maintenance affected the PM H⁺-ATPase activity, which contributed to tolerance under drought stress. These results indicate that 𝛽-glucan soil amendment improves the soil water content during drought and affects the water supply in sweet potatoes. Consequently, 𝛽-glucan is a potential material for maintaining soil water contents, and analysis of the major PM proteins is one of the indicators for evaluating the biopolymer effect on plant survival under drought stress.

• 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.