• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.312-318
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• 1998

The potentials of some Korean wild plants as a phytoremediator for cleaning heavy metal pollution were measured. Several plant species, Ambrosia trifida, Brassica juncea, Rumex crispus, and Abutilon theophrasti screened previously for phytoremediator were treated with cadmium and copper solution. In order to know the growth response to heavy metal stress, the plants were cultivated in hydroponic system containing heavy metals with different concentration. To know the effects of heavy metals on emergence and seedling growth, seeds of 4 species were sown in the pot and watered with heavy metal solution adjusted pH to 6.5, 5.5, and 4.5. A proposed species as potential phytoremediator, A. trifida, showed tolerance to $20{\mu}mol/L$ Cd and $80{\mu}mol/L$ Cu in nutrient solution without apparent growth reduction, and up to $100{\mu}mol/L$ Cd and $400{\mu}mol/L$ Cu without critical visual injury. Up to 311mg/kg of Cd and 369mg/kg were accumulated in dried aerial part in A. trifida. In contrast, A. theophrasti showed injury at $400{\mu}mol/L$ Cu. Significant differences were shown in Cu accumulation among the four species. A. trifida had much higher concentrations of Cd in the shoot, whereas R, crispus accumulated higher concentrations of Cd in the shoot. Testing plant species showed reduced emergence rate with heavy metal treatment. When pH was lowered, the emergence and seedling growth were affected severely with heavy metal. We can suggested that A. trifida was the most proper species for phytoremediation in heavy metal-polluted regions.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.9-22
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• 2009

Due to increasing concerns over issues with both water quantity and quality for turfgrass use, research was conducted to determine the response of five warm-season turfgrasses to deficit irrigation and to gain a better understanding of relative drought tolerance. St. Augustinegrass(Stenotaphrum secundatum [Walt.] Kuntze.) cultivars 'Floratam' and 'Palmetto', 'SeaIsle 1' seashore Paspalum(Paspalum vaginatumSwartz.), 'Empire' zoysiagrass(Zoysia japonica Steud.), and 'Pensacola' bahiagrass(Paspalum notatum Flugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at100%, 80%, 60%, or 40% of evapotranspiration(ET). Evaluations included: a) shoot quality, leaf rolling, leaf firing; b) leaf relative water content(RWC), soil moisture content, chlorophyll content index(CCI), canopy photosynthesis(PS); c) multispectral reflectance(MSR); d) root distribution; and e) water use efficiency. Grasses irrigated at 100% and 80% of ET had no differences in visual quality, leaf rolling, leaf firing, RWC, CCI, and PS. Grasses irrigated at 60% of ET had higher values in physiological aspects than grasses irrigated at 40% of ET. 'Sealsle 1' and 'Palmetto' had a deeper root system than 'Empire' and 'Pensacola', while 'Floratam' had the least amount of root mass. Photosynthesis was positively correlated with visual assessments such as turf quality, leaf rolling, leaf firing, and sensor-based measurements such as CCI, soil moisture, and MSR. Reducing the amount of applied water by 20% did not reduce turfgrass quality and maintained acceptable physiological functioning.

• Korean Journal of Environmental Agriculture
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• v.19 no.2
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• pp.166-170
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• 2000

This study was conducted in to elucidate the changes of growth characteristics and photosynthesis in three soybean (Glycine max L. cv. Danwonkong, Hwangkeumkong and Kwangankong) 30 day old seedlings to 100mM NaCl concentration containing 1/2 Hoagland's nutrient solution in sand culture. The main stem height and number of main stem node were decreased. thus, leaf area and dry matter were decreased with 100mM NaCl. Growth reduction was less little in Hwangkeumkong than other cultivars. The stem growth rate was affected less than other parts as root or leaf, by NaCl treatment. The specific leaf area (SLA), shoot : root ratio and leaf : root ratio decreased with NaCl solution except for those of Hwangkeumkong. There is no general tendency in leaf thickness by leaf position of three cultivars. The chlorophyll content (SPAD) of the primary and 2nd leaf slightly decreased under NaCl solution but rapidly increased in non-NaCl solution at 15 days after treatments. The photosynthesis, stomatal conductance and transpiration of 2nd leaf positions reduced by NaCl and there were a sigificant correlation between photosynthesis and stomatal conductance or transpiration.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.591-607
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• 2013

The objectives of the study were to evaluate the aquatic environment of an urban stream using various ecological parameters of biological biomarkers, physical habitat quality and chemical water quality and to develop a "Multimetric Eco-Model" ($M_m$-E Model) for the ecosystem evaluations. For the applications of the $M_m$-E model, three zones including the control zone ($C_Z$) of headwaters, transition zone ($T_Z$) of mid-stream and the impacted zone ($I_Z$) of downstream were designated and analyzed the seasonal variations of the model values. The biomarkers of DNA, based on the comet assay approach of single-cell gel electrophoresis (SCGE), were analyzed using the blood samples of Zacco platypus as a target species, and the parameters were used tail moment, tail DNA(%) and tail length (${\mu}m$) in the bioassay. The damages of DNA were evident in the impacted zone, but not in the control zone. The condition factor ($C_F$) as key indicators of the population evaluation indicator was analyzed along with the weight-length relation and individual abnormality. The four metrics of Qualitative Habitat Evaluation Index (QHEI) were added for the evaluations of physical habitat. In addition, the parameters of chemical water quality were used as eutrophic indicators of nitrogen (N) and phosphorus (P), chemical oxygen demand (COD) and conductivity. Overall, our results suggested that attributes of biomarkers and bioindicators in the impacted zone ($I_Z$) had sensitive response largely to the chemical stress (eutrophic indicators) and also partially to physical habitat quality, compared to the those in the control zone.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.1
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• pp.20-35
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• 2017

In the case of the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure will be significantly generated due to pore volume change associated with rearrangement soil grains. This effect will lead a seabed liquefaction around and under structures as a result of the decrease in the effective stress, and eventually the possibility of structure failure will be increased. The study of liquefaction potential for regular waves had already done, and this study considered for irregular waves with the same numerical analysis method used for regular waves. Under the condition of the irregular wave field, the time and spatial series of the deformation of submerged breakwater, the pore water pressure (oscillatory and residual components) and pore water pressure ratio in the seabed were estimated and their results were compared with those of the regular wave field to evaluate the liquefaction potential on the seabed quantitatively. Although present results are based on a limited number of numerical simulations, one of the study's most important findings is that a safer design can be obtained when analyzing case with a regular wave condition corresponding to a significant wave of the irregular wave.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.6
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• pp.361-374
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• 2016

When the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure is generated significantly due to pore volume change associated with rearrangement soil grains. This effect leads a seabed liquefaction around and under structures as a result from decrease in the effective stress, and the possibility of structure failure is increased eventually. These facts shown above have been investigated in the previous studies related to regular and irregular waves. This study suggested a concrete mat for preventing the seabed liquefaction near the submerged breakwater. The concrete mat was mainly used as a countermeasure for scouring protection in riverbed. According to installation of the concrete mattress, the time and spatial series of the deformation of submerged breakwater, the pore water pressure, and the pore water pressure ratio in the seabed were investigated. Their results were also compared with those of the seabed unprotected with the concrete mat. The results presented were confirmed that the liquefaction potential of seabed under the concrete mattress is significantly reduced under regular wave field.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.83-89
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• 2002

The effect of low dose $\gamma$ radiation on photosynthesis and the reduction of photoinhibition in red pepper plant was investigated. The seedling height leaf width and leaf length of pepper were stimulated in plants grown from seeds irradiated with the low dose of 4 Gy. The $O_2$ evolution in the 4 Gy irradiation group was 1.5 times greater than in the control. To investigate the effect of low dose $\gamma$ radiation on response to high light stress, photoinhibition was induced in leaves of pepper by illumination of high light (900 $\mu mol/m^2/s$). Pmax was decreased with increasing illumination time by 20% in the control, while hardly decreased in the 4 Gy irradiation group. The photochemical yield of PSII, estimated as Fv/Fm, was decreased with increasing illumination time by 50% after 4 hours while Fo did not change. However, Fv/Fm in the 4 Gy irradiation group was decreased by 37% of inhibition, indicating that the photoinhibition was decreased by the low dose $\gamma$ radiation. Changes in the effective quantum yield of PSII, $\Phi_{PSII}$, and 1/Fo-1/Fm, a measure of the rate constant of excitation trapping by the PSII reaction center, showed similar pattern to Fv/Fm. And NPQ was decreased after photoinhibitory treatment showing no difference between the control and the 4 Gy irradiation group. These results showed the positive effect of low dose $\gamma$ radiation on the seedling growth and the reduction of photoinhibition.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.419-425
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• 2004

Two different groups (30 and 60 inds.) of olive flounder (Paralichthys olivaceus) were abruptly (within 30 min) exposed to hypo-salinities from seawater (SW, 35$\textperthousand$) to freshwater (FW, 0$\textperthousand$) (30FW and 60FW) and to 35$\textperthousand$ (30SW and 60SW) in a flow through seawater culture systems. Analysis of plasma samples showed the following significant increase at 0$\textperthousand$: cortisol from $2.8\;ng\;mL^{-1}$ to $66.9\;ng\;mL^{-1}$ (30FW) and from $2.7\;ng\;mL^{-1}$ to $314.1\;ng\;mL^{-1}$ (60FW) after 24 hours of exposure; glucose from $15.8\;mg\;dL^{-1}$ to $257.7\;mg\;dL^{-1}$ after 3 hours exposure and to $164.0\;mg\;dL^{-1}$ after 24 hours in 60FW. Plasma $Na^+$ concentration of 30FW and 60FW were decreased until 24 hours after expose. However that in 30SW and 60SW showed no significant differences. Plasma $Cl^-$ concentration of 60FW was decreased from $59.0\;mEq\;L^{-1}$ to $43.5\;mEq\;L^{-1}$ and to $30.0\;mEq\;L^{-1}$ after 3 and 24 hours of exposure, respectively. At all experimental groups, survival were 100% until 24 hours.

• Journal of Marine Life Science
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• v.4 no.2
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• pp.91-95
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• 2019

The changes of plasma cortisol concentration to high water temperature on common carp, Cyprinus carpio were studied. 20℃, 24℃ and 28℃ groups showed significantly increased plasma cortisol levels until 6 hours, and decreased plasma cortisol levels after 24 hours. Cortisol levels of 20℃ and 24℃ groups decreased to values close to the cortisol content before the experiment. However, 32℃ group showed significantly increased plasma cortisol levels until 24 hours, and maintained plasma cortisol level until 48 hours. The Cumulative mortality rates of 20℃, 24℃ and 28℃ groups increased until 12 hours, and maintained until 48 hours. Cumulative mortality rate of 32℃ group increased continuously until the end of the experiment. Using the results of this study, it could be used as a method to confirm the risk of mass perish in a specific area through hormone analysis.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.174-182
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• 2018

Background: In this study, we observed their growth and physiological responses using a variety of duty ratio under the mixed light using red, blue, and white lights. The red+blue mixed light was treated with 95%, 90%, 85%, 80%, and 75% duty ratios and red+blue+white mixed light with 85% and 70% duty ratios. We examined the width and length of leaves, total number of leaves, and number of shoots to examine their growth responses. The physiological responses were studied by measuring their photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, chlorophyll content, and fluorescence ($F_o$, $F_m$, and $F_v/F_m$). Results: We found that lower duty ratio caused the length and width of the leaves to grow longer under red+blue mixed light but that it did not cause any difference in the red+blue+white mixed light condition. In addition, there was no difference in the number of leaves and shoots among all treatments. In the red+blue mixed light condition, the photosynthetic rate was no difference, but both transpiration rate and stomatal conductance were the highest at 95% duty ratio than in other ratios. Water use efficiency pattern was similar to that of photosynthetic rate; water use efficiency was no difference. Chlorophyll content was the highest at 95% duty ratios, and it was the least at 90%, 85%, and 75% duty ratio. $F_o$ and $F_m$ values were relatively high at 85% and 80% duty ratio and low at 90% duty ratio while $F_v/F_m$ showed no difference. Conclusions: Under the red+blue+white mixed light, all physiological items showed no difference between 70 and 85% treatments. But, photosynthetic rate, water use efficiency, chlorophyll content, and $F_v/F_m$ were relatively greater in the red+blue+white mixed light than in the red+blue mixed light. Therefore, red+blue+white mixed light treated with 70% duty ratio could lessen the environmental stress and save more power when cultivating Silene capitata in a plant factory.