• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.390-399
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• 2010

Non-photochemical quenching (NPQ) values for utilizing them to detect osmotic tolerance in plants were examined with two different soybean cultivars, an osmotic tolerant soybean (Shinpaldalkong 2) and a control soybean (Taekwangkong). Two different stresses were applied to the cultivars as the restricted irrigations of 200 and 50 ml water $pot^{-1}\;d^{-1}$ for 5 days for a control and a drought stress, respectively, and a sodium chloride solution of 200 mmol for 6 days for a salt stress. The intact leaves of the two cultivars after treatment were used to measure chlorophyll fluorescence parameters, maximum efficiencies of photosystem II photochemistry (Fv/Fm), efficiencies of photosystem II photochemistry (${\Phi}_{PSII}$), $CO_2$ assimilation rate ($P_N$), and NPQ. Leaf water potentials of the two cultivars decreased from - 0.2 to - 0.8MPa by a drought treatment and from - 0.7 to - 1.7MPa by a salt treatment. Leaf water content of Shinpaldalkong 2 after a salt treatment was less decreased than that of Taekwangkong. $F_v/F_m$ values of both cultivars were not changed, while ${\Phi}_{PSII}$ and $P_N$ were decreased proportionally to leaf water potential decrease. The response of NPQ was occurred in Shinpaldalkong 2 under the drought and salt stresses. With Taekwangkong cultivar, only drought stress referred NPQ response. The cultivar differences on chlorophyll fluorescence parameters were found in the relationships between ${\Phi}_{PSII}$ and $P_N$, and between NPQ and ${\Phi}_{PSII}$. Although the positive relationships between ${\Phi}_{PSII}$ and $P_N$ were established on all treatments of both cultivars, the decreasing rate of ${\Phi}_{PSII}$ to $P_N$ was smaller in Shinpaldalkong 2 than Taekwangkong. The NPQ was increased according to the decrease of ${\Phi}_{PSII}$ by osmotic treatments in Shinpaldalkong 2. The complementary relationships between NPQ and ${\Phi}_{PSII}$ were well maintained at all treatments in Shinpaldalkong 2, while these relationships were lost at a salt treatment in Taekwangkong. Taken together, the results suggest that analysis of complementary relationships between ${\Phi}_{PSII}$ and NPQ could be more valuable and applicable for determining osmotic tolerance than single analysis of each parameter such as $F_v/F_m$, ${\Phi}_{PSII}$ and NPQ.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.185-191
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• 2003

The mechanism imparting salt tolerance to crop plants remains still unsolved, although soybean has been classified as a susceptible plant to NaCl. To determine optimum parameters on physiological responses for improving sensitivity of salinity in breeding program, soybean (Glycine max Merr., cv. "Gwan-gan") plants were grown in a greenhouse, treated 20 days after emergence for 7 days with NaCl at 0, 30, 60, and 90mM, corresponding to electric conductivity of 1.2, 4.4, 7.3, and 10.4 dS/m, respectively, and assessed 30 days after treatment. Chlorophyll contents were significantly decreased by NaCl ($0.4{\sim}1.0\;mg/g$) compared to control (1.2 mg/g). Photosynthesis rate by NaCl treatment at $0{\sim}90\;mM$ at flowering stage was ranged from 5.0 (control) to $9.6\;{\mu}mol/m^2/s$. Oxygen for respiration was consumed from 5.4 to $9.7\;{\mu}mol/m^2/s$ so that the ratio of $O_2$ (evolution:consumption) was increased with the increase of NaCl, indicating that $O_2$ consumption seems to go beyond $O_2$ evolution. Water potential of leaf at vegetative stage II was ranged from -0.6 to -1.8 MPa and the highest level was observed at mid-day. Water potential by salt stress was decreased with range of $-2.1{\sim}-2.7MPa$ compared to control. Transpiration was decreased from 17% to 20% by NaCl stress. Water vapor diffusing resistance of intercellular air space was affected significantly, increasing up to $16{\sim}24%$ compared to control by NaCl treatment. Salt-treated soybean tended to accumulate $Na^+$, specially in root, with reduced absorption of N, P, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ contents. Free proline content of soybean leaf as affected by different NaCl concentrations was increased 4.2 times ($184{\sim}434\;{\mu}g/g$) more than control. NaCl also increased activities of nitrate reductase and peroxidase by $28{\sim}161%$ and $3{\sim}22%$, respectively. The results show that physiological characteristics of soybean plants during assay were useful as the best parameters of salt stress or salt tolerance test to improve sensitivity in screening and breeding program among cultivars or germplasms.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.293-299
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• 2015

High temperature is one of major environmental stress. Heat tolerance managing is difficult through the phenotypic selection, so marker assistant selection (MAS) using molecular markers like as RAPD, SSR etc. was tried to select useful traits for heat tolerance. Fourteen SSR markers reported by previous research were selected for this research. We tried to evaluate 14 SSR markers for MAS using 31 useful wheat resources including 24 crossing line from Turkey, six Korean wheat cultivars and Chinese spring. The average of the number of alleles and PIC values in this study were 6.14 and 0.64, respectively. Two major clades and four sub clades were grouped by phylogenetic tree using UPGMA. Four Korean wheat cultivars were distinct from other Turkey resources in the phylogenetic dendrogram. From the results, we expected that these markers were able to adapt to screening wheat genotyping for heat tolerance.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.266-287
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• 2004

The non infecting, plant associated bacteria have attracted increased attention for stimulating plant growth and as environmental friendly plant protecting agents. Pink-pigmented facultatively methylotrophic bacteria (PPFMs), classified as Methylobacterium spp., are persistent colonizers of plant leaf surfaces. As the leaves of most or all plants harbor PPFMs that utilize leaf methanol as their sole source of carbon and energy, which is a specific attribute of the genus Methylobacterium. Although they are not well known, these bacteria are co-evolved, interacting partners in plant metabolism. This claim is supported, for example, by the following observations: (1) PPFMs are seed-transmitted, (2) PPFMs are frequently found in putatively axenic cell cultures, (3) Low numbers of seed-borne PPFMs correlate with low germinability, (4) Plants with reduced numbers of PPFM show elevated shoot/root ratios, (5) Foliar application of PPFMs to soybean during pod fill enhances seed set and yield, (6) Liverwort tissue in culture requires PPFM-produced vitamin B12 for growth, (7) treated plants to suppress or decrease disease incidence of sheath blight caused by Rhizoctonia solani in rice, and (8) the PPFM inoculation induced number of stomata, chlorophyll concentration and malic acid content, they led to increased photosynthetic activity. Methylobacterium spp. are bacterial symbionts of plants, shown previously to participate in plant metabolism by consuming plant waste products and producing metabolites useful to the plant. There are reports that inform about the beneficial interactions between this group of bacteria and plants. Screening of such kind of bacteria having immense plant growth promoting activities like nitrogen fixation, phytohormone production, alleviating water stress to the plants can be successfully isolated and characterized and integration of such kind of organism in crop production will lead to increased productivity.

• Toxicological Research
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• v.17 no.3
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• pp.187-194
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• 2001

The oxidative stress causes the cell damage and death and thereby, stimulates membrane lipid peroxidation. In this study, the correlation between the lipid peroxidation product and the parameter of liver fibrosis (cirrhosis) was investigated in cholestasis induced rats. The Sprague-Dawley rats were divided into 3 groups (sham: sham operation, BDL/S-I and BDL/S-II : bile duct ligation/scission) and were observed for 2 or 4 weeks. After observation period, the organs were weighed and the ratio of organ weight/body weight was calculated. Sera and liver tissue were used for the measurement of malondealdehyde (MDA), parameter of clinical biochemistry, total collagen content and the staining. The ratio of organ weight/body weight in BDL/S-I and BDL/S-II was significantly increased compared to sham operated group. Serological parameters (Alanine transaminase, Aspartate transaminase, Alkaline phosphatase and Total bilirubin) in BDL/S-I and BDL/S-II group were significantly higher than those in sham operated group. Concentration of MDA in BDL/S-I (261%) and BDL/S-II(790%) was significantly increased compared to MDA in sham operated group. And the content of hydroxyproline (hyp) in BDL/S-I and BDL/S-II group was significantly increased 2~4 times than in sham operated group. The good correlations between hyp in liver tissue and MDA in sera of sham operated group and all operated group were found (r=0.825). The significantly higher value of MDA, hyp and serological parameters in BDL/S-I and BDL/S-II group suggests the stimulation of lipid peroxidation and chronic liver damage. Especially the activation of lipid peroxidation and the stimulation of liver fibrosis was stronger in BDL/S-II group than in BDL/S-I group. The stronger fibrosis, portal-portal septum formation, the more massive bile duct proliferation in portal triads and stroma, and hepatocytes swelling were observed in liver tissue of and BDL/S-II group compared to BDL/S-I group. Conclusively, a good correlation between MDA as a lipid peroxidation marker and hyp as a liver fibrotic parameter could be connected with the process of liver fibrosis. Moreover, cholestasis condition may cause jaundice, activation of lipid peroxidation, and collagen accumulation in liver. Additionally, optimal observation period of bile duct obstruction for the screening of antioxidant and antifibrotic effect in rats would be four weeks.