• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.554-561
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• 1999

A novel estimation method was investigated for determining the concentrations of residual biomass, poly-3-hydroxybutyrate (PHB), and main nutrients including carbon and nitrogen sources, phosphate, and mineral ions from the supplied amount of ammonia solution used for a pH-control solution and nitrogen source in a PHB fermentation. The estimation equations for a batch culture and a fed-batch culture were derived from the relationship between the growth rate of residual biomass and the feed rate of the pH-control solution, and then were applied to the batch culture and the fed-batch cultures of Alcaligenes latus. This method was successfully applied to estimate the concentrations of residual biomass, PHB, and nutrients.

• Korean Journal of Medicinal Crop Science
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• v.24 no.3
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• pp.198-206
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• 2016

Background: Electrical conductivity (EC) and pH are important features of nutrient solution, affecting both growth and quality of crops by altering nutrient uptake. Methods and Results: The pH values of nutrient solutions were controlled at 5.0, 5.5, 6.0, 6.5 and EC values were controlled at 0.68, 0.84, 1.23, 1.41 dS/m. Gingesng root weights were higher during the initial growth period when the plants were treated with low pH and low EC nutrient solutions. However, the higher pH and EC levels, the greater the increase in the rate of root weight between the initial and middle growth periods. The highest ginsenoside amount changed during growth period. The total ginsenoside amount was highest in the root, and the lowest in leaves at 45 and 90 days after treatment, respectively, with solution at a pH of 6.0. After 135 days of treatment, the highest total ginsenoside amount was detected in root treated with soluton with EC values of 1.23 dS/m. Conclusions: For the cultivation of ginseng using a nutriculture system, the pH and EC values of nutrient solutions should to be controlled based on the stage of growth and targeted plant organ (root or leaves).

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.13-20
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• 2007

This study was conducted to collect the basic data fo the development ot hydroponic technique and the efficient promotion of water culture. We have also analysed the water culture associated domestic patent application informations searching for on-line internet site with an admission fee (http://www2.wips.co.kr) from the year 1983 to January, 2006. Fifty nine patent applications related to the hydroponics were searched for in this study. Main patent contents applied were as followed in the order of that nineteen applications about the hydroponic equipments by 32.2%, thirteen applications about the materials used in water culture by 22.0%, eleven applications about the composition of nutrient solution by 18.6%, nine applications about the cultural methods by 15.3%, and seven applications about the cultural media by 11.9%. The compositions of nutrient solution and the cultural methods intended for specific crops were increased in number following five applications about tomato plants and four applications about potatoes. Thirty three patents (55.9%) were mainly applied before the year 2000. Main patent contents were the compositions of nutrient solution before the year 2000 in contrast to the cultural methods and substrates after the year 2000.

• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.188-194
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• 1995

This study was carried out to investigate the effect of NH$_4$H$_2$PO$_4$ on pH stabilization in deep flow culture system using tap water, and to determine the optimum range of NH$_4$H$_2$PO$_4$ in culture solution. The pH of tap water is 7.5. The higher the concentration of NH$_4$H$_2$PO$_4$ was, the more the pH of nutrient solution was decreased. In NH$_4$H$_2$PO$_4$ 4/3-5/3 me/$\ell$, the pH of nutrient solution was 6-7.5 during the experiment. The highest brix(%) was obtained in NH$_4$H$_2$PO$_4$ 5/3-6/3 me/$\ell$. Leaf length, leaf width and stem-base diameter were highest in NH$_4$H$_2$PO$_4$ 2/3 me/$\ell$. The L and b＊ values were highest and the a＊ value was lowest in NH$_4$H$_2$PO$_4$ 8/3 me/$\ell$. Toxicity symptom of ammonium appeared in NH$_4$H$_2$PO$_4$ 8/3 me/$\ell$. It suggests that there was the relationship between leaf color and growth condition. It was concluded that NH$_4$H$_2$PO$_4$ 2/3 me/$\ell$ was good before harvest stage and NH$_4$H$_2$PO$_4$ 5/3-6/3 me/$\ell$ at harvest stage.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.5
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• pp.329-335
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• 2004

Acid deposition in forest adjacent to the industrial complexes causes soil acidification resulting in the leaching of cations, decreases of buffering capacity and increases of toxic metal concentrations such as Al, Fe, Mn and Cu in soil solution. Changes of nutrient availability equilibria by acid deposition have been known to retard the growth of pine trees. Objective of this research was to assess the critical ratios of Ca/Al and Mg/Al limiting the growth of Pinus thunbergii in the hydroponic culture. The Ca concentration and Ca/Al ratio in stalks of pine tree were increased as increasing Ca/Al molar ratio in the nutrient solution, but were not changed when the Ca/Al molar ratio was adjusted to greater than 1. Growth of Pinus thunbergii was inhibited at the Ca/Al molar ratio lower than l due to the Ca deficiency. The molar ratios of Ca/Al in the needles of Pinus thunbergii showed the similar tendency with the stalks. This indicated that Ca/Al molar ratio of 1 in the growth media was the critical level limiting the growth of Pinus thunbergii. Concentration of Mg and Mg/Al molar ratios in the stalks of pine tree were increased as increasing Mg/Al molar ratio in nutrient solution. Molar ratios of Mg/Al in the needles were increased as increasing Mg/Al ratios in nutrient solution up to 0.83, which was the critical level limiting the growth of Pinus thunbergii.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.107-115
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• 2008

Herbs and plants widely used for the ecological restoration were selected for germination rate analysis under treatment of microorganisms to determine ideal treatment conditions and medium for enhanced germination rate. Albizzia julibrissin, when submerged in a nutrient medium or distilled water, presented a decrease in germination period rather than increase in germination rate. When treated with microorganism culture solution (JM-2) for 24 hours, 90% germination was achieved in two days, which is sufficient evidence to conclude that such treatment accelerates the germination of Albizzia julibrissin. Germination period decreased for Lespedeza cyrtobotrya samples submerged in microorganism solution for 15 and 48 hours, however, increases in germination rates were not observed. Sample treated in the solution for 24 hours had increased germination rate and enhanced germination period. Microorganism solution treatment had a negative effect on germination for Lespedeza cuneata, unlike Lespedeza cyrtobotrya and Albizzia julibrissin. Microorganism treated seeds of Lepsedeza cuneata had a lower germination rate than that of the control with no treatment. However, submerging treatments in a nutrient medium or distilled water for 24 to 48 hours were proven effective with higher germination rates than control sample with no treatment. Herbs and plants widely used for the ecological restoration were selected for germination rate analysis under treatment of microorganisms to determine ideal treatment conditions and medium for enhanced germination rate. Albizzia julibrissin, when submerged in a nutrient medium or distilled water, presented a decrease in germination period rather than increase in germination rate. When treated with microorganism culture solution (JM-2) for 24 hours, 90% germination was achieved in two days, which is sufficient evidence to conclude that such treatment accelerates the germination of Albizzia julibrissin. Germination period decreased for Lespedeza cyrtobotrya samples submerged in microorganism solution for 15 and 48 hours, however, increases in germination rates were not observed. Sample treated in the solution for 24 hours had increased germination rate and enhanced germination period. Microorganism solution treatment had a negative effect on germination for Lespedeza cuneata, unlike Lespedeza cyrtobotrya and Albizzia julibrissin. Microorganism treated seeds of Lepsedeza cuneata had a lower germination rate than that of the control with no treatment. However, submerging treatments in a nutrient medium or distilled water for 24 to 48 hours were proven effective with higher germination rates than control sample with no treatment.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2000.10a
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• pp.73-76
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• 2000

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.252-260
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• 2008

This study was conducted to observe the characteristics of mineral nutrient uptake of single-node cutting rose 'Versilla' and to determine optimal nutrient solution control method for soilless culture of 'Versilla' in a closed hydroponic system. Nutrient solution was managed by five different control methods: macro- and micro-element control in aeroponic system (M&M), macroelement control in aeroponic system (M), nutrient solution supplement in aeroponic system (S); electrical conductivity (EC) control in aeroponic system(EC-A); EC control in deep flow technique system(EC-D). The concentration of $NO_3$-N exceeds optimal range whereas P and Mg decreased at the later stage of plant growth with the EC control method, EC-A and EC-D. The overall mineral nutrient content increased with S. On the other hand the nutrient content at the root environment was maintained optimal with M&M and M. The nutrient solution control methods had significantly effect on the cut-flower quality. In the M&M and M, flower length, fresh weight and root activity were higher than those with the other mineral nutrients control methods. The maximal efficiency of photochemistry (Fv/Fm) was higher for M&M, M and S than that with EC-A and EC-D. Based on the above results, it is highly recommended to control nutrient solution by mineral nutrient control methods (M&M and M) in a closed hydroponic system for single-node cutting rose, 'Versillia'.

• Korean Journal of Environmental Agriculture
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• v.9 no.1
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• pp.53-59
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• 1990

Root zone environments in hydroponics are very important factors in crop growth, development and quality. In Korea, improvement of root zone temperature is required because of the continental climate. Therefore, this investigation was carried out to clarify the difference of root zone environments in different hydroponic systems under different climates. Tomato plants were grown in nutrient solutions at Seoul City University and Allen Cooper's. Hydroponic systems in this experiment were aeroponics, nutrient film technique(NFT), rockwool culture, sand culture and smoked rice hull culture(SRH). The decrease in temperature rapidly occured in sand culture while slowly in rockwool culture in low air temperature periods. The internal temperature of substrates of hydroponic bed were slightly changed in rockwool culture under high air temperature periods, while the duration of high temperature was longest in NFT. Electrical conductivity and pH of nutrient solution showed great changes in rockwool and aeroponics. Along the bed, the content of dissolved oxygen in nutrient solution had a tendency to decrease in NFT and DFT(Deep flow technique), while didn`t a change with aeroponics. Root activity measured by triphenyl tetrazolium chloride (TTC) was highest with aeroponics, followed by rockwool culture and NFT.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.354-362
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• 2009

This study was performed to develop a suitable nutrient solution for standard rose substrate culture in a closed hydroponic system. 1/4, 1/2, 2/3 and 1 strength of the nutrient solution made by Japan National Institute of Vegetable and Tea Science (JNIVT) were supplied. The photosynthesis rate, quality and growth of cut flower were higher in the 1/2 and 2/3 strength of nutrient solution during high and low temperature period. Based on the above results, optimum nutrient solutions (UOS) were composed by nutrientwater (n/w) absorption ratio with 1/2S ($NO_{3^-}N$ 6.8, $NH_{4^-}N$ 0.7, $PO_{4^-}P$ 2.0, K 3.8, Ca 3.0, Mg 1.2, $SO_{4^-}S$ $1.2me{\cdot}L^{-1}$) at high temperature season and 2/3($NO_{3^-}N$ 9.7, $NH_{4^-}N$ 0.8, $PO_{4^-}P$ 2.2, K 5.0, Ca 3.9, Mg 1.5, $SO_{4^-}S$ $1.5me{\cdot}L^{-1}$) at low temperature season. The results of suitability examination showed that the EC level in newly composed nutrient solution (UOS) was more stable than other nutrient solutions due to its large amount of calcium and potassium. The growth of cut flower cultivated with UOS was higher than those of other nutrient solutions. Especially, the yield of cut flowers in UOS nutrient solution increased 1.4 times than that of other nutrient solution treatments. Consequently, the new nutrient solution investigated in this experiment was suitable for rose cultivation in a closed hydroponic system.