• Horticultural Science & Technology
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• v.31 no.6
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• pp.726-731
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• 2013

Experiments were conducted to evaluate the effect of low temperature-darkness treatment on floral initiation in four kinds of Korean strawberry cultivars. Mother plants were planted on March 29 and daughter plants were raised for the experiment. Temperature treatment was done for 7, 14, and 21 days keeping $13^{\circ}C$ in cooling storage from August 29, September 5 and September 14 to September 21. After the treatment, flower bud initiation was examined by a microscope, and the seedlings were transplanted on hydroponic system with Yamazaki's strawberry solution of EC $0.8dS{\cdot}m^{-1}$ to check the flowering. 'Ssanta' and 'Maehyang' showed early flower bud initiation in 7 days treatment than 'Seolhyang' by microscope check. 'Ssanta', 'Daewang', and 'Maehyang' showed early flower bud initiation in 14 days treatment than 'Seolhyang'. There were no differences among the treatments in 21 days treatment. Percentage of flowering of 'Seolhyang' and 'Maehyang' by low temperature-darkness treatment didn't show any difference but 'Daewang' and 'Ssanta' showed high percentage of flowering. It suggested that low temperature-darkness treatment technique can be use for improving early flowering and yield of 'Ssanta' and 'Daewang' cultivars.

• Journal of Life Science
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• v.17 no.12
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• pp.1729-1733
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• 2007

Brassinolide insensitive associated receptor kinase 1(BAK1) is a critical component that play an important roles in signaling of brassinosteroid biosynthesis. Brassinosteroid-deficient and -insensitive mutants showed the characteristic of dwarf symptom. The nutrient deficient tomato showing stunt phenomenon was selected from soiless cultivation system using modified Sonneveld hydroponic solution. Twenty eight protein spots showing different expression levels compared to the control were isolated from extracts of stunted tomato leaves by 2D PAGE analyses. Significantly down-regulated 6 protein spots out of 28 protein spots were analyzed and sequenced by MALDI-TOF mass spectrometry. The protein spot having pI=4.5 and MW=24 kDa was identified as a signal protein, BAK1, which is directly related to brassinosteroid biosynthesis. In addition, five other protein spots were identified as BCK1, cystein proteinase, sulfutase, peroxidase and zinc finger factor respectively, and they were also signal proteins related to brassinosteroid biosynthesis. Furthermore, amplification of 500bp of BAK1 mRNA by RT-PCR using a primer set of peptide matched regions was inhibited conpared to that of the wild type. The results sugested that the BAK1 might be regulated at the transcription level in response to nutrition applications.

• Journal of Biosystems Engineering
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• v.40 no.1
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• pp.89-93
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• 2015

Purpose: Machine vision-based image processing methods can be useful for estimating the fresh weight of plants. This study analyzes the ability of two different image processing methods, i.e., morphological and pixel-value analysis methods, to measure the fresh weight of lettuce grown in a closed hydroponic system. Methods: Polynomial calibration models are developed to relate the number of pixels in images of leaf areas determined by the image processing methods to actual fresh weights of lettuce measured with a digital scale. The study analyzes the ability of the machine vision- based calibration models to predict the fresh weights of lettuce. Results: The coefficients of determination (> 0.93) and standard error of prediction (SEP) values (< 5 g) generated by the two developed models imply that the image processing methods could accurately estimate the fresh weight of each lettuce plant during its growing stage. Conclusions: The results demonstrate that the growing status of a lettuce plant can be estimated using leaf images and regression equations. This shows that a machine vision system installed on a plant growing bed can potentially be used to determine optimal harvest timings for efficient plant growth management.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.510-523
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• 2020

This study analyzed groundwater quality in hydroponic cultivation facilities. Through this study, the possibility of groundwater use was evaluated according to the quality of the groundwater for hydroponic cultivation facilities. Good groundwater quality, on average, is pH 6.61, EC 0.27 dS/m, NO3-N 7.64 mg/L, NH4+-N 0.80 mg/L, PO4-P 0.09 mg/L, K+ 6.26 mg/L, Ca2+ 18.57 mg/L, Mg2+ 4.38 mg/L, Na+ 20.85 mg/L, etc. All of these satisfy the water quality standard for raw water in nutrient cultivation. But in the case of farmers experiencing problems with groundwater quality, most of the items exceeded the water quality standard. As a result of the analysis, it was judged that purifying groundwater of unsuitable quality for crop cultivation, and using it as raw water, was effective in terms of water quality and soil purification. If an agricultural water purification system is constructed based on the results of this study, it is judged that the design will be easy because the items to be treated can be estimated. If a purification system is established, it can use groundwater directly in the facility and for horticulture. These study results will be available for use in sustainable agriculture and environments.

• Journal of Biosystems Engineering
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• v.32 no.2 s.121
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• pp.109-114
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• 2007

In mass production of seed-potato plantlets, the processes for in vitro propagation and ex vitro acclimatization with a high cost should be improved by a culture system with environmental control using scaled-up culture vessels. The experiment was conducted to design a hydroponic culture system for enhancement of growth and development of seed-potato (Solanum tuberosum) plantlets cultured under photoautotrophic (without sugar in culture medium) conditions with controlled light intensity and ventilation rate. The culture system was consisted of scaled-up culture vessels, ventilation pipes, a multi-cell tray and an environmental control system (ECS) for optimum controlling in temperature, light intensity, ventilation rate, and culture-medium supply. Growth and development of the plantlets was significantly increased under the ECS compared with a conventional culture system (CCS) of photomixotrophic culture (with sugar in culture medium) using small scale vessels. For 21 days, leaf area of the plantlets was expanded more than 2 times, and number of internodes also approximately 4 times greate. under the ECS. In addition, the photoautotrophic growth in sweetpotato (Ipomoea batatas) and chrysanthemum (Chrysanthemum morifolium) plantlets was greater more than 2 times compared with the CCS.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.249-257
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• 2017

Agastache rugosa, is a perennial medicinal plant commonly used in Chinese herbalism, and may have anti-atherogenic and antibacterial properties. Here in this study, we investigated the growth and variations in antioxidant contents of A. rugosa in response to nutrient solution and photosynthetic photon flux density (PPFD) with artificial lighting for a hydroponics culture. Fluorescent light at 150, and $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD with a 16/8 (light/dark) photoperiod, combined with four different nutrient solutions [developed by Horticulture experiment station in Japan (HES), University of Seoul (UOS), Europe vegetable research center (EVR), Otsuka-house 1A (OTS)], were used in a hydroponics culture system for 6 weeks. The shoot and root dry weights of A. rugosa grown with the OTS were significantly higher than those of other nutrient solutions. The amount of tilianin was the highest grown with the OTS, followed by EVR, HES, and UOS. Total acacetin content was the highest in A. rugosa grown under EVR which was statistically similar with OTS. The A. rugosa grown under $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD produced higher fresh weight and both acacetin and tilianin contents than that grown under $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD. The present results suggested that OTS along with $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD could be an optimum growing condition for better growth and higher accumulation of tilianin and acacetin contents in A. rugosa with hydroponic culture systems in a plant factory.

• Research in Plant Disease
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• v.11 no.2
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• pp.193-197
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• 2005

The effect of pH on the survival of R. solanacearum and its transmission via roots of tomato in hydroponic culture were studied in laboratory and greenhouse. In laboratory experiment, R. solanacearum could not survive for 24h in nutrient solution with pH of $4{\cdot}0;or\;4{\cdot}5$, while 1, 14, 51 and $62\%$ of inoculum survived at pH $5{\cdot}0,\;5{\cdot}6\;and\;6{\cdot}5$, respectively. When tomato plants were inoculated with R. solanacearum through wounds on the stems, the bacteria moved downward from the inoculation site to the roots and infectious bacteria were released from the roots into the nutrient solution. Of two pH regimes tested in greenhouse nutrient-film technique(NFT) culture, the R. solanacearum population was significantly lower in pH 5.0 than in pH 6.5 in most sampling data. In treatments in which R. solanacearum was introduced by transplanting two root-inoculated plants, significantly move plants developed wilt at pH $6{\cdot}5$(34 out of 48 plants) than at pH 5.0(11 out of 48 plants). In addition, when the bacterium was introduced by transplanting two stem-inoculated plants at pH $6{\cdot}5$, seven out of 24 plants developed wilt.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.292-299
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• 2022

This study was conducted to analyze physical and chemical properties of horticultural substrates and response of hydroponically grown two cultivars of 'Namcheon' and 'Somirang' perilla by four different substrates: coir (chip:dust = 5:5), perlite, granular rockwool, and commercial mixed substrate (cocopeat:peatmoss:vermiculite:perlite: zeolite = 50:25:10:10:5). There were no significant differences in EC and pH according to substrates. Container capacity was the greatest in granular rockwool, and it showed appropriate levels in mixed substrate and coir. Air space was higher in coir and perlite than the other treatments. Bulky density reached a proper standard in all substrates excepting coir. The leaf length and width of 'Namcheon' indicated the most in mixed substrate, though the value of 'Somirang'was greatest in coir substrate. The leaf weight of both cultivars was highest in mixed substrate, and relatively low in coir and perlite. The total yield of leaves was separated by two groups: higher group, which are mixed substrate and granular rockwool, and lower group, which are coir and perlite. There was a large gap by 28% between these two groups. Therefore, this study suggests that substrates with high water holding capacity such as mixed substrate or granular rockwool are most suitable for the hydroponic cultivation of perilla, which require sufficient moisture supply to the root zone.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.149-158
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• 2014

The effects of spot cooling on growing ever-bearing strawberry in hydroponic cultivation during summer by spot cooling system was estimated in plastic greenhouse located in Pyeongchang. The temperature of cooling water was controlled by heat pump and maintained at the range of $15{\sim}20^{\circ}C$. Cooling pipes were installed in root zone and very close to crown. Spot cooling effect was estimated by applying system in three cases which were cooling root zone, crown plus root zone, and crown only. White low density polyethylene pipe in nominal diameter of 16 mm was installed on crown spot, and Stainless steel flexible pipe in nominal diameter of 15A was installed in root zone. Crown and root zone cooling water circulation was continuously performed at flowrates of 300 ~ 600 L/hr all day long. Strawberry yields by test beds were surveyed from Aug. 1 to Sep. 30. The accumulated yield growth rate compared with a control bed of crown cooling bed was 25 % and that of crown plus root zone cooling bed was 25 % and that of root zone cooling bed was 20 %. The temperatures of root spot in root zone cooling was maintained at $18{\sim}23.0^{\circ}C$ and that of crown spot in crown cooling was maintained at $19{\sim}24^{\circ}C$. Also, the temperatures of root spot in crown plus root zone cooling bed was maintained at $17.0{\sim}22.0^{\circ}C$ and that of crown spot was maintained at $19{\sim}25^{\circ}C$.

• Environmental Engineering Research
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• v.19 no.2
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• pp.145-149
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• 2014

Arsenic (As) is one of the heavy metals which causes acute bio-toxicity even at low concentration and has disastrous effect on environment. In some countries, As contamination has become alarming and increasing day by day as consequences of unsustainable management practices. Many existing physical, chemical and biological processes for As removal from water system are not feasible due to techno-economic limitations. The present study highlights the scope of biological strategy for As removal through phytoextraction. Arsenic uptake and accumulation in the biomass of three plant species and their As tolerance abilities have been investigated to develop an efficient phytoextraction system in combination of these plant species. Three non-crop plant species, Pteris vittata; Mimosa pudica, and Eichhornia crassipus were treated with 0-200 mg/L As in liquid nutrient solution for 14 days. P. vittata accumulated total 9,082.2 mg (8,223 mg in fronds) As/kg biomass and Eichhornia total 6,969 mg (4,517 mg in fronds)/kg biomass at 200 mg/L As concentration, respectively. Bioaccumulation factor (BF) and translocation factor (TF) were estimated to differentiate between excluders, accumulators and accumulation in above ground biomass. Pteris and Eichhornia have highest BF (67 and 17) and TF (64 and 3), respectively. In contrast, Mimosa accumulated up to 174 mg As/kg plant biomass which is low in comparison with other two plants, and both BF and TF were ${\leq}1$. This study reveals that Pteris and Eichhornia are As hyperaccumulator, and potential candidates for As removal from water system.