• Korean Journal of Environmental Agriculture
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• v.4 no.1
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• pp.18-24
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• 1985

A pot experiment was conducted to study the influence of potassium and cesium carrier on the uptake of radionuclide $Cs^{137}$ which is an element released usually from nuclear facilities, by paddy rice upon prolonged cropping of contaminated soils. The results are summarized as follows: 1) Visual toxic symptoms on the growth of rice plant due to treatment of radioactive cesium were not observed up to $20 {\mu}Ci/10Kg$ soil in a pot. 2) The yield and potassium content in rice plant were increased with potassium application, while the reverse was true for the calcium and magnesium. The addition of potassium to the soil markedly reduced $Cs^{137}$ uptake by rice plant but the addition of Cs carrier increased $Cs^{137}$ uptake. 3) Potassium and $Cs^{137}$ showed uniform distribution in all parts of plant and the contents of these two elements were high in the stems and leaves, and low in the heads. The ratio of $Cs^{137}$ to K was, however, not uniform in all parts of a plant. It was shown that this ratio was higher in the seed part, that is, chaff and hulled grain than in the leaves and stems. 4) $Cs^{137}$ absorption rate in rice plant was remarkably reduced with increase of potassium application and it was ranged from $0.02{\sim}0.47%$ in potassium non-treated plot to 0.01∼0.04% in plot treated with a concentration of 16Kg/10a. 5) The amount of $Cs^{137}$ and potassium uptake of rice plant depended on soil type. Uptake of $Cs^{137}$ by rice plant was higher in the soil with low pH and potassium content. The $Cs^{137}$ uptake by rice plant decreased as the potassium content and pH of soil was increased, but $Cs^{137}$ uptake increased when CEC and clay content in soil was high.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.138-145
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• 2007

The effects of amylopectin and hydrocolloid (locust bean gum and guar gum) content on wheat flour dough and noodle properties were investigated. As the amount of amylopectin increased, the water absorption rate (farinograph), the tension (tension test), the gel stability (freeze-thawing treatment), and the springiness and the cohesiveness (TPA) increased, but the pasting temperature (RVA), the lightness and yellowness (color measurement), and the hardness (TPA) tended to decrease. In sensory evaluations, the scores for cohesiveness, springiness, and acceptability of cooked noodle increased as the proportion of amylopectin increased. The proper combination of amylose/amylopectin ratio and hydrocolloids improved the freeze-thaw stability and the sensory acceptability of wheat flour dough and noodle.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.8-15
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• 2003

If contaminated river water is sprayed over a floodplain, the microbial processes can simultaneously remove organic matter and nitrogen during the infiltration through the sediment profile. The effect of rhizosphere on the removal of organic matter and nitrogen from contaminated river water was investigated using floodplain lysimeters. River water was sprayed at a rate of $68.0L\;m^{-2}\;d^{-1}$ on the top of the lysimeters with or without weed vegetation on the surface, Concentrations of $NO_3$, $NH_4$ and dissolved oxygen (DO), and chemical oxygen demand (COD) and Eh in water were measured as functions of depth for 4 weeks after the system reached a steady state water flow and biological reactions. A significant reductive-condition for denitrification developed in the 30-cm surface profile of lysimeters with weeds. At a depth of 30 cm, COD and $NO_3$-N concentration decreased to 5.2 and $0.9mg\;L^{-1}$ from the respective influent concentrations of 18.2 and $9.8mg\;L^{-1}$. The removal of $NO_3$ in lysimeters with weeds was significantly higher than in those without weeds. Vegetation on the top was assumed to remove $NO_3$ directly by absorption and to create more favorable conditions for denitrification by supply of organic matter and rapid $O_2$ consumption, In the lysimeters without weeds, further removal of $NO_3$ was limited by the lack of an electron donor, i.e. organic matter. These results suggest that the filtration through native floodplains, which include rhizospheres of vegetation on the surface, can be effective for the treatment of contaminated river water.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.3
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• pp.157-163
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• 2005

The increasing of greenhouse gases may change agricultural environment. The agronomic productivity will depend upon change of temperature, precipitation, solar radiation and fertilization. Particularly, nitrogen fertilization considerably influences rice productivity and agricultural environments. This experiment was conducted to study transformation of nitrogen and to determine the primary yield components responsible for yield differences in paddy soil. $NH_4-N$ concentration of NPK plot in surface water of paddy soil was $2.07mg\;L^{-1}$ at 5 days after transplanting, and then was decreased sharply due to rice absorption and loss to environment. $NO_3-N$ concentration of NPK plot in surface water was $3.97mg\;L^{-1}$ at 10 days after transplanting. $NO_3-N$ concentration range of CRF plot in surface water was $3-5mg\;L^{-1}$ at 30th after transplanting. The accumulation of $NH_3$ volatilization in NPK plot was $22.39kg\;ha^{-1}$, which accounted for 20% of N fertilizer applied but using of CRF fertilizer can reduce $NH_3$ volatilization by 67% in paddy soil. Use efficiency of N fertilizer was not different between CRF70% and CRF100% plot. Rate of N use efficiency were 27.4%, 51.2%, 49.0% in paddy field NPK, CRF70% and CRF100% plots respectively. The yield of CRF70% showed the best effect with 9.3% increase production ratio, compare with NPK plot.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.5-11
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• 2002

In this study, new development of natural ventilation window was accomplished to control environment of greenhouse with no use of farced ventilation during hot season. The ventilation effect of developed ventilation window was investigated in experimental greenhouse which was designed using side wall panel and folding type panel fur natural ventilation. Folding panel type ventilation window was designed to open upper part of the side wall and top of the roof using two hinges which are located bottom of the side wall and the roof panel to grab one side of each panels and guide the other side along with the guidance rail. Developed ventilation window has top ventilation part with maximum moving distance X=ι (1-cos$\theta$)=848.5 mm and side ventilation part with maximum moving distance Y=ι/2 $\times$sin$\theta$=1,184.4 mm at 45$^{\circ}$ of theoretical opening angle. It took 4.5 minutes to open roof vent fully and temperature at 1.2 and 0.8 m height decreased after 1 minute from starting opening and became equilibrium state maintaining 3-4$^{\circ}C$ difference after 2 minutes from complete opening. Air exchange rate was 15.2~39.3 h$^{-1}$ which was more than 10~15 h$^{-1}$ of continuous type and Venlo type greenhouse. The descent effect of temperature by ventilation windows was two times higher than Venlo type greenhouse.

• Journal of Applied Biological Chemistry
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• v.53 no.2
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• pp.65-70
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• 2010

Medium-chain fatty acids (MCFA) are composed of 8-12 carbon atoms, and are found in coconut, cuphea, and palm kernel oil. MCFA were introduced into clinical nutrition in the 1950s for dietary treatment of malabsorption syndromes because of their rapid absorption and solubility. Recently, MCFA have been applied to Gastrointestinal Permeation Enhancement Technology (GIPET), which is one of the most important parts in drug delivery system in therapeutics. Therefore, to accumulate the MCFA in seed oil of rapeseed, much effort has been conducted by classical or molecular breeding. Laurate can be successfully accumulated up to 60 mol% in the seed oil of rapeseed by the expression of bay thioesterase (Uc FatB1) alone or crossed with a line over-expressing the coconut lysophosphatidic acid acyltransferase (LPAAT) under the control of a napin seed-storage protein promoter. Also, caprylate and caprate were obtained 7 mol% and 29 mol%, respectively, from plants over-expressing of the medium-chain specific thioesterase (Ch FatB2) alone or together with the chain-length-specific condensing enzyme (Ch KASIV). Despite the success of some research in utilizing parallel classical and molecular breeding to produce MCFA, commercially available seed oils have for the most part, not been realized. Recent research in the field of developing MCFA-enriched transgenic plants has established that there is no single rate-limiting step in the production of the target fatty acids. The purpose of this article is to review some of the recent progress in understanding the mechanism and regulation of MCFA production in seed oil of rapeseed.

• Korean Journal of Environmental Biology
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• v.18 no.2
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• pp.269-277
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• 2000

When Persicaria thunbergii and Rumex crispus were treated with Cd($NO_3$)$_2$ and Pb($NO_3$)$_2$ of 5 or 10 mM for 5 days, the amount of bioaccumulation of $Pb^{2+}$ in the leaf of P. thunbergii was 2.87-8.08$\mu\textrm{g}$/g and that of $Cd^{2+}$ was 0.82-2.79$\mu\textrm{g}$/g. In the case of P. thunbergii, the concentration of $Pb^{2+}$ in the leaf was higher than that of $Cd^{2+}$. On the other hand, in R. crispus, the concentration of $Cd^{2+}$ and $Pb^{2+}$ were similar as follows ; 1.49$\mu\textrm{g}$/g in $Cd^{2+}$ 5mM, 2.90$\mu\textrm{g}$/g in Cd2+ 10mM, 1.83$\mu\textrm{g}$/g in $Pb^{2+}$ 5mM and 2.73$\mu\textrm{g}$/g in $Pb^{2+}$ 10mM. The remaining rate of heavy metals and the variation of pH in the cultured soil decreased as compared with control (100 % and pH 6.48) after 5 days as follows; to 77.l% and pH 6.39 in $Cd^{2+}$ 5mM, 90.2% and pH 5.79 in $Cd^{2+}$ 10 mM, 81.1% and pH 6.00 in $Pb^{2+}$ 5mM, and 85.7% and pH 5.80 in $Pb^{2+}$ 10 mM. The result of size exclusion chromatography, several phytochelatins were seperated from the extract of the leaf of both plants treated with heavy metals. The molecular mass of these phytochelatins were estimated as follows; in the case of P. thunbergii, about 4,300-8,600 da by $Cd^{2+}$ and about 3,200-9,700 da by $Pb^{2+}$, and in R. crispus, about 4,300 da by $Cd^{2+}$ and about 3,200-7,500 da by $Pb^{2+}$. In addition, $A_{254}$ of these phytochelatins were higher than $A_{280}$. [Phytochelatin, Persicaria thunbergii, Rumex crispus]

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.255-264
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• 2001

This study was conducted to investigate changes in inorganic phosphorus fractions in phosphorus accumulated plastic film house soils under cropping condition. Pot experiment was conducted with surface soils taken from plastic film house fields cultivated for 3, 8 and 16 years. Phosphorus fertilizer was applied at the rates of 0 (P0), $100kg\;ha^{-1}$ (recommended application rate. P1) and $200kg\;ha^{-1}$ (P2) as fused phosphate. Crops were grown sequentially in the order of corn-Chinese cabbage-Chinese cabbage-corn for 3 years. The content of easily soluble-P fraction was decreased with cropping. There were significantly positive relationship not only between the contents of easily soluble-P and the amounts of soil available P ($r=0.839^{**}{\sim}0.952^{**}$ for Bray-1 P, $r=0.895^{**}{\sim}0.967^{**}$ for Lancaster P, and $r=0.491^{**}{\sim}0.821^{**}$ for Olsen P), but also between the amounts of P absorbed by plants and the amounts of easily soluble P decreased ($r=0.644^{**}{\sim}0.822^{**}$). The decrease of easily soluble-P during cropping period could be described by a first-order reaction. The number of cropping times needed to decrease the content of easily soluble-P to an index level of $0.2mg\;kg^{-1}$, which is commonly reported as the desired concentration for soil P, was predicted in the range of 26~33 cropping times by using the equations. Regardless of P fertilization, the proportion of Al-P to total P was little varied during cropping period, but the proportion of Fe-P to total P increased with cropping. Although the content of Ca-P was high before cropping, the proportion of Ca-P to total P was increased with cropping. The proportion of reductant soluble-P to total P was little varied for P fertilizer treatment but was increased for no P fertilizer treatment. The residual-P was decreased during cropping period due to the absorption by crops and the conversion to other inorganic P fractions.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.2
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• pp.93-101
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• 2007

In order for bioremediate the benthic layer in polluted inner Bay, the effects of irradiance and wave-length irradiated from light emission diode (LED) on the growth of benthic diatom Nitzschia sp. (Hakozaki Bay strain of Japan) were investigated. The Nitzschia sp. was cultured under blue LED (450 nm), yellow LED (590 nm), red LED (650 nm) and fluorescent lamp (mixed wavelengths). At $25^{\circ}C$ and 30 psu, the growth of Nitzschia sp. showed its peak at $20\;{\mu}mol\;m^{-2}\;s^{-1}$ (blue LED) and $40\;{\mu}mol\;m^{-2}\;s^{-1}$ (fluorescent lamp), and was inhibited at the irradiance higher than that irradiance. Nitzschia sp. in yellow LED and red LED is fitted by a rectangular hyperbolic curve because no photoinhibition was observed under maximum irradiance used in this study. The irradiance-growth curves were described as ${\mu}=-0.46{\exp}(1-I/6.32)+0.46-0.00043I,\;(r^2=0.98)$ under blue LED, ${\mu}=0.42(I+7.87)/(I+58.9),\;(r^2=0.99)$ under yellow LED, ${\mu}=0.39(I+3.39)/(I+21.6),\;(r^2=0.94)$ under red LED, ${\mu}=-0.38{\exp}(1-I/7.23)+0.38-0.00016I,\;(r^2=0.96)$ under fluorescent lamp. Maximum specific growth rate of blue LED, yellow LED, red LED and fluorescent lamp was $0.44\;day^{-1},\;0.42\;day^{-1},\;0.39\;day^{-1}$ and $0.37\;day^{-1}$, respectively. The absorption coefficient ($a_{ph}$) of Nitzschia sp. was similar under all the wavelengths (400 nm-700 nm), although maximum $a_{ph}$ was $0.0224\;m^2\;mg\;chi.\;{\alpha}^{-1}$ in 472 nm and $0.0179\;m^2\;mg\;chi.\;{\alpha}^{-1}$) in 663 nm. The results may indicate the possibility of environmental improvement around the benthic layer in polluted coastal area because microphytobenthos growth is stimulated by means of irradiated blue LED at the benthic boundary layer during both autumn and winter, and yellow LED, which might have been suppressed growth of harmful algae, at the layer during both spring and summer.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.278-286
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• 2009

In this study, four natural Mn oxides ($NMO_1-NMO_4$) was characterized using x-ray diffraction, scanning electron microscopy, and their removal efficiency for 1-naphthol (1-NP) in aqueous phase, using batch reactor, was investigated. The results were compared with one another and a synthetic manganese oxide, birnessite. The NMOs have a various Mn minerals including pyrolusite (${\beta}-MnO_2$), cryptomeltane (${\alpha}-MnO_2$) as well as birnessite (${\delta}-MnO_2$) depending on their sources, which results in different removal efficiencies (removals, kinetics) and reaction types (sorption or oxidative-transformation). The comparative study showed that $NMO_1$ (electrolytic Mn oxide) have a higher removal efficiency for 1-NP via oxidative-transformation compared to birnessite. The 1-NP removals by NMOs were followed by pseudo-first order reaction, and the surface area-normalized specific rate constants ($K_{surf},\;L/m^2$ min) determined were in order of $NMO_1(3.31{\times}10^{-3})$>${\delta}-MnO_2(1.48{\times}10^{-3}){\fallingdotseq}NMO_3(1.46{\times}10^{-3})$>$NMO_2(0.83{\times}10^{-3})$>$NMO_4(0.67{\times}10^{-3})$. From the solvent extraction experiments with the Mn oxide precipitates after reaction, it was observed that the oxidative-transformation rates of 1-NP were in order of $NMO_1{\fallingdotseq}{\delta}-MnO_2$>$NMO_3$>$NMO_4{\gg}NMO_2$ and the analysis of HPLC chromatogram and UV-Vis. absorption ratios ($A_{2/4}$, $A_{2/6}$) on the supernatant confirmed that the reaction products were oligomers formed by oxidative-coupling reaction. Results from this study proved that natural Mn oxide (except $NMO_2$) used in this experiment can be effectively applied for the removal of naphthols in aqueous phase, and the removal efficiencies are depending on the surface characters of the Mn oxides.