• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.667-677
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• 2020

Crop water stress can be detected based on soil moisture content, crop physiological characteristics and remote-sensing technology. The detection of crop water stress is an important issue for the accurate assessment of yield decline. The crop water stress index (CWSI) has been introduced based on the difference between leaf and air temperature. In this paper, drone-based thermal infrared image was used to map of crop water stress in water control plot (WCP) and water deficit plot (WDP) over spring chinese cabbage fields. The spatial distribution map of CWSI was in strong agreement with the abnormal growth response factors (plant height, plant diameter, and measured value by chlorophyll meter). From these results, CWSI can be used as a good method for evaluation of crop abnormal growth monitoring.

• Corrosion Science and Technology
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• v.22 no.1
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• pp.44-54
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• 2023

The rupture disk corrosion test (RDCT) method was recently developed to evaluate stress corrosion cracking (SCC) and was found to have great potential for the real-time detection of SCC initiation in a high temperature and pressure environment, simulating the primary water coolant of pressurized water reactors. However, it is difficult to directly measure the stress applied to a disk specimen, which is an essential factor in SCC initiation. In this work, finite element analysis (FEA) was performed using ABAQUS^TM to calculate the stress and deformation of a disk specimen. To determine the best mesh design for a thin disk specimen, hexahedron, hex-dominated, and tetrahedron models were used in FEA. All models revealed similar dome-shaped deformation behavior of the disk specimen. However, there was a considerable difference in stress distribution in the disk specimens. In the hex-dominated model, the applied stress was calculated to be the maximum at the dome center, whereas the stress was calculated to be the maximum at the dome edge in the hexahedron and tetrahedron models. From a comparison of the FEA results with deformation behavior and SCC location on the disk specimen after RDCT, the most proper FE model was found to be the tetrahedron model.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.307-314
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• 1998

The response of water stree under high and low temperatures, was shown differently according to the longer the suspension period of water supply. Leaf photosynthetic rate(LPS), leaf water potential(WP), relative leaf water content and relative soil water content were lower. At the higher temperatures, the percentate of reduction in LPS and WP was greater than at low temperatures. It is suggested that evaporation rate should be higher in the high temperature than the lower temperature. Also leaf water potential was lower at high temperature than at low temperature. After the 9 th day of treatment , LSP was remarkably reduced at high temperature, but the reduction of LPS was not significant at low temperature. Solidago virga-aurea var. asiatic that maintained LPS of 3rd day after treatment was more strong than other varieties at low temperatures. The silting and curling of leaves were observed symptoms of stress on the 9th day at the both temperatures. The leaves of aster scaber and Ligularia fischeri turned red on the 9th day after treatment at low temperature.

• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.288-299
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• 2017

This study was conducted to find out the influence of drought stress on physiological responses of Synurus deltoides. Drought stress was induced by withholding water for 25 days. Leaf water potentials were decreased of both predawn (${\Psi}_{pd}$) and mid-day (${\Psi}_{mid}$) with increasing drought stress, but water saturation dificit (WSD) was 7 times increased. ${\Psi}_{pd}-{\Psi}_{mid}$ showed the significant difference of 0.22~0.18 MPa in stressed before 10 days, and nonsignificant as treatment time became longer. A strong reduction of stomatal conductance ($gH_2O$) and stomatal transpiration rate (E) were observed after 15 days of drought stress Significant reductions of net apparent quantum yield (${\Phi}$) and maximum photosynthesis rate ($Pn_{max}$) were observed after 20 days of drought stress; However, water use efficiency (WUE) was shown the opposite trend. This implies that decrease of photosynthesis rate may be due to an inability to regulate water and $CO_2$ exchanged through the stomata. From JIP analysis, flux ratios (${\Psi}_O$ and ${\Phi}_{EO}$) and performance index on absorption basis ($PI_{ABS}$) were dramatically decreased withholding water after 15 days, which reflects the relative reduction of photosystem II activity. The leaf of S. deltoides showed osmotic adjustment of -0.35 MPa at full turgor and -0.40 MPa at zero turgor, and also cell-wall elastic adjustment of 9.4 MPa, indicating that S. deltoides tolerate drought stress through osmotic adjustment and cell-wall elastic adjustment. The degree of change in water relations parameters such as Vo/DW, Vt/DW decreased with increasing drought stress. This result showed that S. deltoides was exhibited a strong reduction of photosynthetic activity to approximately -0.93 MPa of predawn leaf water potential, and both of osmotic adjustment and cell-wall elastic adjustment in drought stress condition appears to be an important adaptation for restoration in this species.

• YAKHAK HOEJI
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• v.49 no.4
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• pp.291-298
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• 2005

Gardenia Jasminoides(GJ) is traditionally used for treatment of hepatic disease, insomnia, anxiety, and inflammatory disease. The aim of this study is to examine effects of GJ extract in response to stress. Animals of the normal group were not exposed to any stress and the control group were exposed to stress. The rats of the Ginseng and GJ supplementary group were orally administered once a day with 100mg of red ginseng extract, 100mg of GJ extract/kg body weight. The mice were given water containing 200mg of red ginseng extract, 200mg of GJ extract/100ml potable water. Animals were given supplements for 7 days without stress, and then were given supplements for 5 days with restraint and electroshock stress. After loading final stress, we examined stress related behavioral changes of experimental animals and measured the levels of blood corticosterone. GJ-supplementation partially blocked the stress effect on locomotion and elevated plus maze test in rats, and also partially blocked stress-induced behavioral changes such as freezing, burrowing, face-washing, smelling and rearing behavior in rats. The effect was almost equipotent to Ginseng's effect. GJ-supplementation didn't influence on fatigue related behavior or physical stress resistance. GJ-supplementation decreased the levels of blood corticosterone which is increased by stress in rats. These results suggest that GJ protects partially the living organism from stress attack and it has the potential to be used as a functional material to alleviate stress response.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.3
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• pp.185-192
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• 2003

This study consolidation undrain Triaxial Compression Tests using constant confining pressure in clay that receive preconsolidation stress that is different and, void ratio, pore water pressure coefficient, shear strength compare with another thing theory and studied analyzing change relation of elastic modules. The summary of analysis is follows: If preconsolidation stress increases in same confining stress in relation of preconsolidation stress and deviator stress, deviator stress is proportional and increased. Can know that excess void pressure is proportional and decreases in size of preconsolidation stress in same confining stress state if preconsolidation stress increases preconsolidation stress and relation of excess void pressure. Also, over consolidated state can assume that this is thing by Dilatancy's effect though excess void pressure decreased remarkably. Preconsolidation stress and relation of stress path can know that shear strength degree increases preconsolidation stress increases, and specially, preconsolidation stress was appear in stress path form of overconsolidated state case of clay that receive at 300, 400, 500kPa in 100, 150kPa's deviator stress.

• The Journal of Pediatrics of Korean Medicine
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• v.19 no.2
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• pp.99-114
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• 2005

Objectives: This study was aimed to find out the anti-stress and protective-memory effect of Quibitanggagam(QBT) on stress of rats Methods : This experimental study was conducted with elevated plus maze test, passive avoidance test, morris water maze test, and consequently density of AchE reactivity in the CA1 of hippocampus to research the learning and memory of rats affected by restraint stress, Results: Passive avoidance test revealed that time latency of retention test for QBT+Stress group significantly decreased on 2, 3rd day. Morris water maze revealed that acqusitive ability of QBT+Stress group significantly improved on 2, 3rd day and retentive ability of QBT+Stress group was significantly improved on 7th day. Elevated plus maze test revealed that latency in open arm of QBT+Stress group significantly decreased and locomotor activity(number of entered arm) of QBT+Stress group was significantly increased. The values of density of AchE stained nuclei in the CA1 of hippocampus QBT+Stress group was significantly increased compared with SAL+Stress group. Conclusion : According to the above results, it is concluded that QBT will be useful as a remedy against stress disease and improving memory.

• 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 Medicinal Crop Science
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• v.28 no.6
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• pp.412-420
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• 2020

Background: Measurement of chlorophyll fluorescence (CF) is useful for detection the ability of plants to tolerate environmental stresses such as drought, and excessive sunlight. Cnidium officinale Makino is highly sensitive to water stress and excessive sunlight. In this study, we evaluated the effect of soil water and shade treatment on the photosynthesis and leaf temperature change of C. officinale. Methods and Results: C. officinale was cultivated under uniform irrigation for 1 week drought stress (no watering) for 6 days. A significant decrease in CF was observed on the 5th day of withholding water (approximately 6% of soil water content) regardless of shading. Notably, the Rfd_lss parameter (CF decrease rates) with and without shade treatment was reduced by 73.1% and 56.5% respectively, at 6 days compared with those at the initial stage (0 day). The patterns of the degree of CF parameters corresponded to those of the soil water content and difference between leaf temperature (Ts) and air temperature (Ta). Meanwhile, CF parameters recovered to the 3 - 4 days levels after re-watering, while the soil water potential was completely restored. The suitable soil water content for C. officinale optimal growth was between -5 kPa and -10 kPa in this experiment. Conclusions: Lack of soil water in the cultivation of C. officinale, even with shading, decreased latent heat cooling through transpiration. As a result, heat dissipation declined, and the plant was subjected to drought stress. Soil water content plays a major role in photosynthesis and leaf temperature in C. officinale.

• The Journal of Internal Korean Medicine
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• v.19 no.1
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• pp.247-270
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• 1998

The more society has complicated, the more we have met stressful circumstance. And it is found that many physical and mental symptoms induced by stress. Soyosan(SYS) is one of the well-known oriental medicine for the treatment of general syndrome induced by emotional stress. This study was taken to know effects of SYS water extract on immune-depressed mice induced by stress. The results obtained in this study were as follows : 1. SYS inhibited murine weight-loss induced by stress 2. In vivo& in vitro, SYS increased phagocytic activity. 3. SYS enhanced the production of such reactive oxygen intermediates as superoxide and hydrogen peroxide from macrophages. 4. In vitro, SYS little influenced the production of reactive nitrogen intermediates. 5. SYS increased the number of the rosette forming cells of spleen. 6. SYS changed the ratio of helper and suppressor T cells by increasing $CD4^+$ T cells and decreasing $CD8^+$ T cells. 7. SYS increased cytotoxic activity on human lymphoma cell line(K562). 8. SYS increased the plasma level of GH and DHEA. whereas it decreased that of ACTH and cortisol. According to the above results, it might be considered that SYS would be used for immune-depressive disease induced by stress.