• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.196-202
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• 2005

This research was conducted to determine the amount of water absorbed by a polyacrylamide hydrogel such as Stocksorb C (STSB), effect of salts on inhibition in hydration of STSB, and the hydrogel effects on changes of nutrient concentration in external solution. Absorption of deionized water by STSB reached a maximum of 180 $mL{\cdot}g^{-1}$. Monovalent soluble salts such as $KH_2PO_4,\;KNO_3$, and $(NH_4)_2SO_4$ reduced absorption of the hydrogel, but the degrees of inhibition in absorption were similar in three kinds of salts. Twenty milliequivalents per liter of $Ca_{2+}\;or\;Mg_{2+}$ reduced water absorption of STSB to $14\%$ compared to those of deionized water. Solution absorption was consistently lower in the presence of divalent cations than in the presence of the monovalent cations. But the absorption was unaffected by the uncharged salt such as urea in all concentrations tested. The final $K^+\;and\;NH_4^+-N$ concentrations of the solution remaining after absorption by STSB was higher than those of the initial solution. The soaking of STSB to full strength of Hoagland solution resulted in increase of $NO_3^--N,\;H_2PO_4^-\;and\;SO_4^{2-}$ concentrations in external solution compared to initial solution, reaching 5,300, 250 and 1,500 $mL{\cdot}g^{-1}$, respectively, at 24 hrs after soaking.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.387-393
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• 1995

Diffusion coefficients of moisture and solid, reaction rate constants of carotene destruction, and the fitness of drying models for moisture transfer were determined to study the characteristics of mass transfer during osmotic dehydration. Moisture loss and solid gain were increased with increase of temperature and concentration; temperature had higher osmotic effect than concentration. Diffusion coefficient showed similar trend with osmotic effect. Diffusion coefficients of solids were larger than those of moisture because the movement of solid was faster than that of moisture at the high temperature. Reaction rate constants were affected to the greater extent by concentration changes than by temperature changes. Arrhenius equation was applied to determine the effect of temperature on diffusion coefficients and reaction rate constants. Moisture diffusion required high activation energy in $20^{\circ}Brix$, while relatively low in $60^{\circ}Brix$. To predict the diffusion coefficients and reaction rate constants, a model was established by using the optimum functions of temperature and concentration. The model had high $R^2$ value when applied to diffusion coefficients, but low when applied to reaction rate constants. Quadratic drying model was most fittable to express moisture transfer during drying. In conclusion, moisture content of carrots could be predictable during the osmotic dehydration process, and thereby mass transfer characteristics could be determined by predicted moisture content and diffusion coefficient.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.218-222
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• 1999

The effects of storage temperature, moisture content and the concentration of additives, such as sucrose fatty acid ester(SE), isomaltooligosaccharide(IO) and glycerin(GL), on texture properties, hardness(HA), cohesiveness(CO) and chewiness(CH) of Baikseolgi after 7 days storage were analyzed by response surface methodology(RSM). The contour values of HA of SE added Baikseolgi at 20, 50 and $80^{\circ}C$ of storage temperate were $1500{\sim}3200,\;500{\sim}1300$ and $100{\sim}400\;g_f$, respectively. The HA of IO or GL added Baikseolgi decreased with increased storage temperature, moisture content and additive concentration. The storage temperature was the most significant factor affecting the HA of Baikseolgi. However, the second and third significant factors were moisture content and additive concentration, respectively. These results imply that the control of storage temperature is the most effective method to increase the storage stability of Baikseolgi. The CO of IO or GL added Baikseolgi was increased by the change of strage temperature from $20{\circ}\;to\;50{\circ}$. While, there was no significant difference between $50{\circ}\;and\;80{\circ}$ of storage temperature. The CO of IO or GL added Baikseolgi was maximized around 40% of moisture content and that of GL added Baikseolgi was minimized around 0.5% of GL concentration. The storage temperature, additive concentration and moisture content were the first, second and third affacing factors on the CO of Baikseolgi, respectively. The CH of Baikeolgi was decreased by increasing storage temperature, moisture content and additive concentration. The storage temperature, moisture content and additive concentration were the first, second and third affacting factors on the CH of Baikseolgi, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.824-830
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• 1996

In order to minimize the deterioration of osmotic dried apple quality, the characteristics of mass transfer during osmotic dehydration such as solid gain(SG), weight reduction(WR) and moisture loss(ML) were investigated. Moisture and solid transfer were analyzed by Fick's law. The highest (equation omitted)E value was observed with severe browning at $60^{\circ}C.$ The concentration effect on (equation omitted)E were higher at high temperatures than at low temperatures. SG, WR and ML increased as immersion temperature, sugar concentration and immersion time increased. Higher concentration of sucrose led to more sucrose absorption resulting increase in SG. Diffusion coefficients of moisture increased with immersion temperature and sugar concentration. As concentration increased, diffusion coefficients of solids increased at $20^{\circ}C$ while it decreased at $40^{\circ}C$ and $60^{\circ}C.$ Arrhenius equation was appropriately explain the effect of temperature on diffusion coefficients. Moisture and solid diffusion showed high activation energy in 20 。Brix solution, compared with in 40 and 60 。Brix.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.81-85
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• 1999

Concentration change of soil-applied pretilachlor (2-chloro-2',6'-diethyl- N-2-propoxyethyl)-actanilide) was investigated under upland condition with various soil moisture contents ranging from 50 to 80%(water content by weight). Following pretilachlor from each soil solution was extracted by centrifugation using double tubes, its concentration was determined by HPLC. Pretilachlor concentration in the soil solutions were almost the same under various soil moisture conditions. However, the total amount of pretilachlor increased as the soil moisture content increased. With increasing soil moisture content, the bioactivity of soil-applied pretilachlor on inhibiting the growth of Echinochloa ultilis Ohwi et Yabuno and the absorption of $^{14}C$-pretilachlor in its plants were also enhanced. Our results demonstrate that the absorption of pretilachlor in plants varies with soil moisture content and thus the bioactivity of soil-applied pretilachlor on inhibiting plant growth is different under various soil moisture conditions at the same dosage based on air-dried weight.

• Journal of Life Science
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• v.18 no.2
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• pp.154-161
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• 2008

The physiological and photochemical responses of rice seedling to NaCl stress were investigated through measuring leaf relative water content (RWC), root water uptake and chlorophyll fluorescence. When plants were exposed to increased salinity stress, the visual symptoms of injury were significant at ${\geq}$500 mM NaCl concentration for 4 and 5 day stress periods. The differences in Fv/Fm between control treatment and plants treated with 500 mM and 1,000 mM NaCl were evident after 5 day and 4 day, respectively, whereas in root water uptake its effect was observed at 500 mM and 1,000 mM NaCl at 2 day of salt-stressed periods. Leaf RWC in salt-stressed plants decreased gradually with increasing salinity in exogenous solution and duration of salt stress, and these decrease showed leaf RWC of 58-68% atduration over 2 day stress of 1,000 mM NaCl treatment and 88% at 1 day stress. NaCl stress led to a significant inhibition of the light-induced greening in etiolated rice plants, especially in 4 and 5 day salt-stressed plants, which linearly decreased with NaCl concentration ($R^2$=0.812 and 0.918, respectively). The effects of NaCl stress in rice seedlings indicate that water uptake in root is more sensitive to increasing NaCl concentration and stress duration than Fv /Fm in leaves compared with the same NaCl concentration.

• Journal of Life Science
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• v.34 no.6
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• pp.426-433
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• 2024

The environmental stress that plants are most susceptible to is water stress. Abscisic acid (ABA) is a plant hormone synthesized by plants to counteract environmental stress. The role of stomata in plants is to allow the synthesis of sucrose by absorbing CO₂, which greatly affects photosynthetic activity. In addition, stomata are pathways for transpiration, which releases H₂O and help establish a water potential gradient that allows plant roots to continuously absorb water and inorganic substances from the soil. Plants have a mechanism to minimize water loss by closing their stomata when exposed to water-stressed environments. The most well-studied hypothesis concerning the mechanism of stomatal closure is the response to water stress. When a plant receives sufficient water, its stomata open during the day and close at night due to its circadian rhythm. In addition, stomatal closure occurs when the concentration of CO₂ in the intercellular space increases. However, the mechanism of stomatal closure due to circadian rhythm and increased CO₂ concentration in the intercellular space is not well understood. When plants undergo water stress, the increased concentration of ABA in the guard cell cytoplasm induces an increase in Ca²⁺ concentration, resulting in cytoplasmic depolarization. As a result, the outward K⁺-channel of the tonoplast and the slow-type anion channels SLAC1 and SLAH3 are activated, releasing K⁺, Cl^-, and malate^2-, causing the stomata to close. Therefore, in this paper, the mechanism of stomatal closure caused by water stress was investigated.

• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.65-70
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• 1996

Water potential which is an physical chemistry and thermodynamic indicator expressed water status of plant root, stem and fruit could be use as a useful indicator for growth control of hydroponically grown muskmelon plant. Linear relationship was observed between EC and water potential of nutrient solution, consequently increment of EC related to the decreasing water potential and resulted with the alteration of water potential and solute potential of upper leaves. Rapid reduction in growth was observed in over 5${\mu}{\textrm}{m}$ of Cu concentration in the media and same tendency was recorded in the shoot fresh weight, root dry weight and chlorophyll content. Increment of Cu concentration in the nutrient solution leads to lower the growth rate and then the water potential of upper leaves. Turgor pressure was not affected the growth of hydroponically grown muskmelon and also Cu concentration of nutrient solution was not recognized the direct relationship to the growth characteristics of muskmelon. These results demonstrated that water potential of nutrient solution can be use as an useful indicator for water physiological comparison of plant growth in hydroponically grown muskmelon.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.45-45
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• 2022

일당귀[Angelica acutiloba (Siebold & Zucc.) Kitagawa]는 산형과(Apiaceae), 당귀속(Angelica)에 속하는 다년생 식물로 일본이 원산지다. 국내에서는 참당귀(A. gigas)와 더불어 뿌리를 약용의 목적으로 재배하며, 잎과 줄기는 쌈채소로 이용하는 작물 중 하나이다. 본 연구의 목적은 일당귀에 대한 GA₃ 처리 및 온도에 따른 발아특성을 분석하여 약용 및 식용으로 활용도가 높은 일당귀의 재배 및 생산에 대한 기초자료로 사용함에 있다. 연구에 사용된 일당귀의 종자는 강원도 태백시에 위치하는 일당귀 재배농가에서 2021년 10월에 채종한 종자를 구입하여 실험에 사용하였고, 종자의 수분흡수율과 다온도 종자발아기를 활용하여 GA₃농도 4조건(50 ppm, 100 ppm, 500 ppm, 1,000 ppm), 온도 6조건(5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃)에 따른 발아특성을 조사하였다. 연구결과 일당귀 종자 100립의 초기 무게 0.264 g에서 증류수 침지 2시간이 경과 후 약 60 %의 무게가 증가한 0.424 g으로 증가하였고, 이후 5 %내외의 수분흡수율을 보이며 48시간 경과 후 약 120% 증가한 0.587 g을 나타냈으며, 이후 72시간 경과 후 0.582 g으로 측정되어 일당귀 종자의 수분포화도는 약 120%정도 내외로 사료된다. GA₃농도 및 온도에 따른 발아율은 500 ppm의 GA₃농도에서 가장 높은 75.63 %의 발아율을 나타냈으며, 15 ℃와 20 ℃의 온도에서 가장 높은 77.6 %의 발아율을 나타냈다. 하지만 각각의 GA₃농도 및 온도에 따른 발아율은 500 ppm의 GA₃농도, 10 ℃의 온도 처리구에서 가장 높은 89.9 %의 발아율을 나타냈으며, 5 ℃의 온도 처리구에서는 모든 GA₃처리구에서 발아가 진행되지 않았다.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.762-766
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• 2006

To improve water resistance of paperboard used to manufacture the corrugated boxes, effect of surface coating of the liner- board with Na-alginate was investigated by determining the optimum processing conditions such as a optimum alginate concentration for surface coating, plasticizer content, concentration of divalent cations their immersion times, For the surface coating of the liner-board, 2.5% Na-alginate solution was found to be the optimum concentration, and the concentration of glycerol used as plasticizer was effective when 35% alginate concentration was use was Used Immersion of the alginate coated paperboard for 3 min in a $CaCl_2$ solution improved the water resistance properties. As a divalent cation for the insolubilization of the alginate films, $Cu^{2+}$ was found to be as effective as $Ca^{2+}$. Among the platicizers tested, sorbitol was the most effective in reducing water vapor permeability and water solubility of alginate coated paperboard.