• Current Research on Agriculture and Life Sciences
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• v.21
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• pp.1-9
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• 2003

Plants are often subjected to periods of soil and atmospheric water deficit during their life cycle. To find critical levels for identification of tolerant rice variety to salt- and drought-stresses, we investigated the water deficiency in the leaf of a Dongjinbyeo (DJ) cultivar, identified as intolerant variety, subjected to NaCl- and Polyethylene glycol 6000 (PEG)- treatments. The relative water content and water potential in leaf of DJ plant sharply declined along the high concentration and time after treatment in NaCl- and PEG-treated rice plants. To elucidate the method of simple screening of tolerant variety to salt- and drought-stresses, we examined the relationship between relative water content and water potential of leaves in NaCl- and PEG-treated rice plants. The relationship between relative water content and water potential in leaf of DJ plant showed the highest correlation in 80 mM NaCl-treatment, and showed high correlation only 8% PEG treatment. These results indicate that the critical level of salt stress for screening of tolerant rice was 80 mM NaCl at 48 h after NaCl treatment, and the critical concentration of drought stress for screening of tolerant rice was 8% PEG at 96 h after PEG treatment.

• BMB Reports
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• v.30 no.1
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• pp.21-25
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• 1997

The growth. freezing resistance and electrophoretic protein patterns of carrot callus cultures were investigated following treatment with NaCl for various' intervals at 20$^{\circ}C$. Following 7 day exposure to 250 mM NaCl. freezing tolerance increased, which was measured by 2.3.5-triphenyl tetrazolium chloride (TTC) assay and fresh weight was reduced compared to control cells. Changes of electrophoretic patterns of total and boiling stable proteins were investigated using one or two dimensional gel system. Several proteins with molecular weight of 43 and 21 kDa increased by NaCl treatment. The most prominent change was detected in 21 kDa protein. The steady state level of this protein increased in NaCl treated cells, but decreased in control cells. Twenty one kDa protein was detected only in the NaCl treated cell when boiling stable protein was analyzed. The isoelectric point of 21 kDa protein was identified as 5.7. The timing of increase of 21 kDa protein was correlated to freezing resistance which implied the role of this protein in the induction of freezing resistance of the cell.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.4-10
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• 1999

This study was conducted to determine the effects of NaCl stress on nitrogen, ${NH_4}^+$, and ${NO_3}^-$ content of 4 barley cultivar seedlings that were cultured for 10 and 30 days with different NaCl levels (0, 50, 100, and 150 mM) contain-ing 1/4 Hoagland solutions. The sodium ion content in the shoot of barley seedlings sharply increased with an increase of NaCl concentration. After 30 days of NaCl treatment, the sodium content of the shoot at 150 mM NaCl was 27 times higher than in non-saline conditions. The sodium content in the root linearly increased with increasing NaCl concentration. Nitrogen content in the shoot linearly increased with increasing NaCl concentration, but nitrogen content in the root declined above the point where the $Na^+$ content was 3.0 mM/g $Na^+$ in the barley seedling. ${NO_3}^-$ content also decreased with increasing NaCl concentration. ${NH_4}^+$ content in the shoot decreased with NaCl condition, but its content in the root increased with NaCl condition. A positive correlation between ${NO_3}^-$ and ${NH_4}^+$ content was found in the shoot, but their relationship was negative in the root.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.12
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• pp.1578-1582
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• 2007

Contents in polyphenol and vitamin C and their antioxidant activities during storage of Lycii folium prepared by different treatment methods were investigated. The antioxidant activity of extracts prepared from 80% MeOH was evaluated using DPPH radical scavenging and SOD-liked activities. Total phenolic acid contents were 1.34 mg/mL when dry, but extracts during 15-day storage after NaCl 0% treatment decreased. DPPH radical scavenging activity of extracts was 65.48% when dry and decreased during 15-day storage after dry and NaCl 0% treatment. SOD-liked activity was 98.63% in NaCl 0% during 15-day storage after dry. Contents of vitamin C decreased during 15-day storage after dry and NaCl 0% treatment. Consequently, our results indicate that Lycii folium prepared from dry treatment could be a promising biomaterial for the production of functional food for total phenolic acid and vitamin C.

• Korean Journal of Poultry Science
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• v.17 no.2
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• pp.127-133
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• 1990

This study was undertaken to find out the effect of heating time and temperature, pH and NaCl concentration on the heat stability of egg albumen gel during heat treatment. With the transient decrease at 110-$130^{\circ}C$, hardness of heat-set albumen gel was increased as the heating temperature increased. The cohesiveness showed similar trend as well. The lightness was decreased while the yellowness was increased as the heating time and temperature increased. Heat-set albumen gel showed maximum hardness at pH 4.5-5.0 and pH 9.0 High heat treatment($120^{\circ}C$, 30min) showed higher hardness at alkaline range compared to low heat treatment($96^{\circ}C$, 30min.). Color of the albumen gel was relatively dark at acidic range and bright at alkaline range. High heat treatment caused darker albumen gel at alkaline range and brighter albumen gel at acidic range. The addition of NaCl increased hardness and cohesiveness of the albumen gel and improved the lightness after high heat treatment regardless of NaCl concentration.

• Food Science and Preservation
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• v.16 no.6
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• pp.861-868
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• 2009

We investigated the use of mashed red pepper in the manufacture of kimchi using various freezing point depression agents (glucose, pectin, ascorbic acid or NaCl). In sensory evaluation results, overall acceptance seemed to be highly related to NaCl content. Kimchi was prepared using mashed red pepper with different levels of NaCl (3, 5, and 10% w/w), and quality characteristics were investigated during storage at $10^{\circ}C$. Salt concentrations of kimchi prepared with addition of 3, 5, or 10% NaCl, and control kimchi, were 2.28, 2.47, 3.10 and 1.92%, respectively. pH values varied significantly among treatments but acidity levels did not differ significantly except during the early stages of production. With increasing NaCl addition, the acidity of kimchi was lower than that of control samples during later fermentation periods. At day 20, the reducing sugar level in control kimchi had decreased by 70% whereas NaCl treatment caused decreases of 45 - 55%. The vitamin C contents of kimchi prepared with addition of NaCl (125.88-145.23 mg/100 g) were higher than that of control (37.22 mg/100 g). In sensory evaluation tests, appearance and texture did not differ significantly with treatment or fermentation period. When taste and overall acceptance were scored, kimchi prepared with the addition of 3% NaCl attained the highest marks throughout the entire fermentation period.

• Journal of Food Hygiene and Safety
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• v.24 no.4
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• pp.368-372
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• 2009

The viability of Staphylococcus aureus, a significant cause of food poisoning in Korea, on TSA plates was determined after sublethal heating treatments and NaCl treatments. In addition, recovery levels of sublethally injured cells on TSA plates containing different concentrations of NaCl (TSAS) were investigated. The viability decreased significantly with increasing degree of sublethal heating treatments, but increases in NaCl treatment concentrations from 0 to 6% had little effect on the viability. After being sublethally treated at $55^{\circ}C$ for 30 min, bacterial populations were reduced by 7.91, 7.97 and 7.99 log CFU/mL on 2, 4 and 6% TSAS, respectively. After being sublethally treated at 60oC for 30 min, bacterial populations were reduced by 6.46, 6.47 and 6.48 log CFU/mL on 2, 4 and 6% TSAS, respectively. Decimal reduction times (D-value) decreased with increasing NaCl treatment concentrations after sublethal heating at 55 and $60^{\circ}C$. These data imply that the S. aureus cells sublethally injured by insufficient heating processes had a lower recovery rate with increasing NaCl concentrations in the recovery media.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.182-188
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• 1997

The study was carried out to determine an optimum concentration of plant growth regulators(ABA and kinetin) on reducing NaCl toxicity during germination in rice. Plant height of a japonica cultivar Ilpumbyeo in ABA 10$^{-5}$ M was increased, while all treatments of kinetin had no clear effects on increasing the plant height. However, other rice cultivars showed slightly different reaction by PGRs compared with Ilpumbyeo. Germination rate of four rice cultivars was ranged from 53.1 to 58.2％ in NaCl 1.3％. All treatments of kinetin accelerated germination rate of tested rice cultivars except Dasanbyeo compared with NaCl 1.3％ treatment. The higher concentration of ABA and kinetin treatment induced the higher starch content, and while the lower concentration of two plant growth regulators induced the higher sugar content in all four rice cultivars. The free proline content of rice seedlings was highest in Ilpumbyeo among the tested cultivars under NaCl 1.3％ treatment.

• Journal of Plant Biology
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• v.36 no.1
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• pp.113-120
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• 1993

Effects of various NaCl concentrations on salt-tolerant callus of tobacco were investigated. Selection of NaCl-tolerant (S) callus was conducted by subculturing Nicotiana tabacum cv. BY 4 callus in 200 mM NaCl-containing MS medium for more than 18 months. In spite of the long subculture period, characteristics of salt tolerance were maintained very stably. Significant differences were found in ion contents of each callus which was subcultured with treatment of various NaCl concentrations: Na+ and Cl- became higher but Mg2+, Ca2+ and K+ became lower with the increasing external salt contents. Therefore, the ratios of Na+/Ca2+ and Na+/K+ also increased resulting close to those of halophytic property. The contents of chlorophylls and carotenoids in S callus were estimated to 3.1 and 2.9 times more, respectively. than those of non-selected (NS) callus (control). The higher content of external NaCl tended to increase the amount of water soluble proteins and to decrease the amounts of the total sugars, reducing sugars and free amino acids. The activity of peroxidase was increased with higher contents of external NaCl in S callus, but it was maintained at a higher level than S callus at lower NaCl, followed by a subsequent decrease above 80 mM NaCl in NS callus. These results suggest that S callus may have a biological system converting energy source to efficient growth leading to reduction of the growth inhibition under stress environment.