• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.270-278
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• 2021

BACKGROUND: Horticultural plant growth under field and/or greenhouse conditions is affected by the climate changes (e.g., temperature, humidity, and rainfall). Therefore investigation of hydroponics on field horticultural crops is necessary for year-round production of the plants regardless of external environment changes under plant factory system with artificial light sources. METHODS AND RESULTS: Common sage (Salvia plebeia), nasturtium (Tropaeolum majus), and hooker chive (Allium hookeri) plants were hydroponically culturing in the plant factory with blue-red-white LEDs (Light-Emitting Diodes) and fluorescent lights (FLs). Leaf numbers of common sage under mixture LED and FL treatments were 134% and 98% greater, respectively than those in the greenhouse condition. In hooker chives, unfolded leaf numbers were 35% greater under the artificial lights and leaf elongation was inhibited by the conventional sunlight compared to the artificial light treatments. Absorption pattern of NO₃-N composition in hydroponic solution was not affected by the different light qualities. CONCLUSION(S): Plant factory system with different light qualities could be applied for fresh-leaf production of common sage, nasturtium, and hooker chive plants culturing under field and/or greenhouse. Controlled light qualities in the system resulted in significantly higher hydroponic growth of the plants comparing to conventional greenhouse condition in present.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.195-200
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• 2011

The growth, yield and quality of Sedum sarmentosum between soil and hydroponic cultivation were compared to produce high-quality shoots in summer season. The plants were collected from four places in Korea and cultivated in a plastic film house with 50% shading. A 1:1:1 mixtures of sand, upland soil and substrate (N-P-K: 330-220-400 $mg{\cdot}L^{-1}$) was used for soil cultivation, and a nutrient film technique (NFT) with Yamazaki-lettuce nutrient solution used for hydroponics. After 30 days of cultivation, plant height ranged from 18.4 to 21.8 cm and showed no significant difference between soil and hydroponic cultivation. Number of shoot, leaf length, leaf width, number of leaf, fresh weight, and dry weight significantly increased in hydroponics compared to those in soil cultivation. Fresh and dry weights in hydroponics were greater in 'Gunsan' and 'Wando' collections than those in other collections. Stem diameter and compression-force significantly increased in soil cultivation rather than hydroponics with significant differences among collections. However there were no significant differences in shoot bitterness and vitamin C content between cultivation methods or among the collections. Most mineral contents except Fe in hydroponics were higher than those in soil cultivation. K, Na, Zn contents in hydroponics were over 2 times higher than those in soil cultivation.

• The Plant Pathology Journal
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• v.18 no.3
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• pp.142-146
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• 2002

The effect of potassium phosphonate ($KH_2PO_3 or $K_2 HPO_3$) on the control of Phytophthora root rot of lettuce was evaluated in a liquid hydroponic culture. Phosphonate 100 ppm strongly inhibited mycelial growth of Phytophthora species in vitro but did not affect normal growth of lettuce in a greenhouse test. Application of the chemical before infection showed over 94% control value, while it was less than 35% when applied after infection. In a field trial, phosphonate 100 ppm, which was directly supplemented into the nutrient solution, satisfactorily controlled the disease as it did not develop until 28 days after transplanting and remained at less than 2% infection rate at the end of cultivation. Meanwhile, in the control plot, the disease initiated at 7 days after transplanting and developed rapidly reaching over 70% infection rate at 28 days. Population density of the causal pathogen, R drechsleri, in a heavily infested farm was 22.0-25.0 cfu/100 ml of nutrient solution. However, it decreased to 1.3-2.0 cfu/100 ml at 7 days after treatment with phosphonate 200 ppm.

• Journal of Plant Biotechnology
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• v.7 no.3
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• pp.195-202
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• 2005

The effects of constituent amino acids of glutathione (GSH), glutamate (Glu), cysteine (Cys) and glycine (Gly), on GSH synthesis in lettuce seedlings were examined in this study. The GSH concentration of the seedlings was increased to 5.1-fold and 1.6-fold the concentration of the control in the first leaves and roots, respectively, by simultaneous application of these constituent amino acids (Glu+Cys+Gly) at 100 mg/l to the culture solution for two days. In the first leaves and roots of these seedlings, the concentration of GSH was 180.4 and 14.6 nmole/gFW, and non-essential amino acids including Glu, Cys and Gly occupied 93.2% and 84.0% of the total free amino acids, respectively. Application of Cys greatly increased the concentration of GSH in the roots, and application of 50 mg/l Cys increased it to 26.1-fold the concentration in the control. The activity of GSH synthetase was higher in the leaves than in the roots, whereas the activity of ${\gamma}$-glutamylcysteine synthetase was higher in the roots than in the leaves.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.287-292
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• 2002

To establish effective and safe control method against Phytophthora root rot caused by Phytophthora capsici on tomato in hydroponic culture, three pesticides, oxadixyl copper hydroxide 8% WP, metalaxyl copper oxychloride 15% WP, and dimethomorph. dithianon 38% WP at 4 concentration levels were tested on potato dextrose agar medium inoculated with Phytophthora capsici. All pesticides inhibited mycelial growth, but two pesticides of them, metalaxyl copper oxychloride WP and dimethomorph. dithianon WP, were selected as effective pesticides for the efficacy test in a hydroponic culture. Forty days after transplanting of tomato seedlings, 4 ml of sporangia of P. capsici (about 25 sporangi/ml) per plot was inoculated around tomato plant root, and then 5 days after inoculation, the pesticides diluted at 5,000 times were drenched 1, 2 or 3 times per plot on the culture cube at 15 days interval. Fifteen days after drenching, tomato fruits and hydroponic culture solution were sampled for the analysis of pesticide residues. Dimethomorph was detected 0.001 and 0.003 mg/kg in tomato of the plots sprayed 2 and 3 times with dimethomorph dithianon WP of which detection levels were far below compared with 1.0 mg/kg of the Korean MRL of dimethomorph on tomato. Incidences of Phytophthora root rot were $30.5{\sim}50%$ in the plots drenched at 1 or 2 times with metalaxyl.copper oxychloride WP, and $16.7{\sim}25%$ in the plots treated with dimethomorph dithianon WP. However, there was no incidence of Phytophthora root rot in the plots treated at 3 times with both of pesticides, showing no phytotoxic effect. Based on the results, the drenching of these pesticides on the culture cube could be recommended as a very safe and effective control method for Phytophthora root rot in tomato.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.141-152
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• 2020

The rapid on-site measurement of hydroponic nutrients allows for the more efficient use of crop fertilizers. This paper reports on the development of an embedded on-site system consisting of multiple ion-selective electrodes (ISEs) for the real-time measurement of the concentrations of macronutrients in hydroponic solutions. The system included a combination of PVC ISEs for the detection of NO₃, K, and Ca ions, a cobalt-electrode for the detection of H₂PO₄, a double-junction reference electrode, a solution container, and a sampling system consisting of pumps and valves. An Arduino Due board was used to collect data and to control the volume of the sample. Prior to the measurement of each sample, a two-point normalization method was employed to adjust the sensitivity followed by an offset to minimize potential drift that might occur during continuous measurement. The predictive capabilities of the NO₃ and K ISEs based on PVC membranes were satisfactory, producing results that were in close agreement with the results of standard analyzers (R² = 0.99). Though the Ca ISE fabricated with Ca ionophore II underestimated the Ca concentration by an average of 55%, the strong linear relationship (R² > 0.84) makes it possible for the embedded system to be used in hydroponic NO₃, K, and Ca sensing. The cobalt-rod-based phosphate electrodes exhibited a relatively high error of 24.7±9.26% in the phosphate concentration range of 45 to 155 mg/L compared to standard methods due to inconsistent signal readings between replicates, illustrating the need for further research on the signal conditioning of cobalt electrodes to improve their predictive ability in hydroponic P sensing.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1997.11a
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• pp.89-90
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• 1997

우리나라 자생식물 중 파드득나물과 울릉미역취는 주로 식생활에 이용되는 산채류이다. 파드득은 미나리과의 다년초로 반디나물이라고도 부르며, 식물 전체에 털이 없고 독특한 향기를 가지고 있어 대량생산이 가능해지면 그 이용 범위와 수요도 함께 늘어날 것으로 기대된다. 울릉 미역취는 국화과의 다년초로 식용으로 이용되기도 하지만 전초와 뿌리는 피부질환이나 감기, 두통, 타박상등에 효과가 있어 약용으로도 널리 이용되고 있고, 재배면에서 볼 때 울릉 미역취는 보통의 미역취에 비해 대형이고 1년에 4번 수확이 가능하며 강건하므로 최근에는 식용작물로의 가능성이 매우 높아져 이미 울릉도에서는 대량재배가 되고 있다. (중략)

• Journal of Plant Biology
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• v.22 no.4
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• pp.107-113
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• 1979

The present study was carried out to estimate the comparative effects of hydroponic heavy metals (Al, Cd, Hg, and Pb) on ATP content in plant leaves grown with Hoagland solution under green house condition. The two plants, kidneybean(Phaseolus vulgaris L.) and buckwheat(Fagopyrum esculentum M nch), showed similar inhibitory effect of heavy metals on ATP content in order of Hg, Cd, Pb, and Al. But the overall inhibitory effect was greater in kidneybean than in buckwheat. The affinity of heavy metals, in vitro, toward the enzyme (luciferin-luciferase) is in order of Hg, Al, Cd, and Pb, similar to that toward ATP. The results showed that the inhibitory effect of heavy metals on ATP hydrolysis is mainly due to the coordination of heavy metals with enzyme than ATP.

• Korean Journal of Environmental Agriculture
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• v.28 no.2
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• pp.171-178
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• 2009

Water shortages are expected to be a major impact of climate change. This study examined the growth of Chinese cabbage seedling using reclaimed wastewater and waste nutrient solution as alternative irrigation resources. Generally, the concentration of nutrients, such as $K^+$, $NH_4^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$,$NO_3^-$, $PO_4^-$ and $SO_4^{2-}$, in waste nutrient solution was higher than that in wastewater. However, Chinese cabbage seedling irrigated with wastewater was supplied a higher concentration of $Na^+$ and $Cl^-$ than waste nutrient solution. The growth of Chinese cabbage seedling irrigated with waste nutrient solution was similar or higher than those irrigated with groundwater as control, while the growth of those irrigated with wastewater was similar to those irrigated with groundwater. The total nitrogen uptake in Chinese cabbage seedling irrigated with groundwater, waste nutrient solution from organic and inorganic hydroponic cultures, and wastewater was 5.47, 10.02, 5.20, and 4.59 mg/plant, respectively. The nitrogen uptake of Chinese cabbage seedling irrigated with waste nutrient solution from organic hydroponic substrates in a 50% lower dose than recommended was 8.34 mg/plant, which is higher than that of the cabbage irrigated with groundwater. Overall, the results suggest that waste nutrient solution and wastewater can be used as alternate water resources, and can allow a reduction in the amount of fertilizer needed to raise Chinese cabbage seedling.

• The Korean Journal of Ecology
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• v.15 no.2
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• pp.137-145
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• 1992

When exposed to 1, 700 ml of 0.089, 0.445 or 0.890 mM/l cadmius solution, dock (rumex crispus L)plants from heavily polluted chungrangchon site absorbed 0.0404, 0.2244 or 0.4929 mM of cadmium per g dw during the first 4 hours, which were 5.0~30.8 times faster uptake rate than those of water hyacinth (eichhornia crassipes Solm. - laub). Zinc, with which cadmium generally occurs together, did not affect the uptake rate in the concentration range of 0.0306 ~0.0918 mM/l. rumex cripus from chungrangchon site and from less polluted shingalchon site, when exposed to 1, 700 ml of 0.089 mM/l solution for 3 days, removed 68.4% and 63.2%, repectively, of the cadmium initially present in the solution. And when exposed to cadmium solution of the same concentration for the second time after cadmium-free hydroponic culture for three days, these plants removed 76.1% and 66.8% of cadmium, respectively. These removal rates were not significantly different between collection sites or between exposures, but were about 2 times greater for the first exposure, and 2~5 times greater for the second exposure, than those of water hyacinth. these results incate that rumex cripus can absorb, and thus remove, large amount of cadmium ion in wastewater, and so can be used in wastewater treatment, e.g. soil trench method. since there was large difference among the plants in the ability to absorb cadmium, it should be possible to select for strain with greater ability.