• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.130-135
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• 1997

Tomatoes are flooded differently 0, 5, 10 and 15cm, according to the developing stages such as flowering stage under the condition of greenhouse. Along with this, they are treated according to the time condition such as 6, 12, 24, 48 and 120 hours. The results obtained are summarized as follows. Plant height decreased in the depth of $0{\sim}10cm$ for over 48 hours, in the depth of 15cm for over 24 hours. Number of leaves was the same as in control, and it decreased over. Number of flowers and fruit setting of individuals decreased conspicuously according as the depth and the hours got greater and longer. Adventitious root occurred remarkably in the depth of $0{\sim}10cm$, for over 24 hours and in the depth of 15cm, 12 hours. Epinastic curvature increased greatly as the depth and the hours got greater and longer. Diffusion resistance of stomata cell increased as the depth and the hours got greater and longer. Diseases occurred conspicuously as the hours of flooding got longer rather than as the depth greater. The preventing of diseases caused by insecticide was observed, but it was not greater than in the seedling and transplanting stage. Fertilization was effective in the case of increasing the weight of shoot. Number of fruits per plant did not decrease in the depth of 0cm up to 24 hours, but decreased on the deeper level of flooding and increased as the hours got longer. Moreover with the exception of 120 hours per respective depth of the treatment, average weight of a fruit got greater as the depth and the hours got greater and longer. In the case of epinastic curvature and diffusion resistance, there was negative correlation between all the other investigated characters and positive correlation between weight of a fruits and average weight of a fruit.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.398-403
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• 2012

This study was carried out to investigate the effect of irrigation method adopted for reducing nutrient solution drainage on the root zone environment, growth and yield of a tomato crop grown in a rockwool medium. The irrigation control methods used were large quantity irrigation at a long interval controlled by only an integrated solar radiation sensor (standard), medium quantity irrigation at a medium interval (zero drainage 1), and small quantity irrigation at a short interval (zero drainage 2) controlled by both an integrated solar radiation sensor and a zero drainage sensor. The amount of the nutrient solution supplied and the drain percentage per plant of the standard, zero drainage 1, and zero drainage 2 were 1.4, 0.9 and 0.8 L, and 23.8, 8.6 and 3.7%, respectively. The average, minimum, and maximum water contents and EC of the standard, zero drainage 1, and zero drainage 2 were 64.5~88% and $1.5{\sim}3.5dS{\cdot}m^{-2}$, 40.3~76.0% and $2.5{\sim}4.0dS{\cdot}m^{-2}$, and 56.3~69.0% and $2.7{\sim}3.7dS{\cdot}m^{-2}$, respectively. There was no difference in leaf width, number of leaves, and stem diameter among the treatments. However, plant height and leaf length decreased in the zero drainage 1 and 2 treatments as compared to the standard. The fruit marketable yield per 10a in the zero drainage 1 and 2 treatments was about 93 and 88%, respectively, of that in the standard treatment.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.401-409
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• 2021

This study aimed to estimate the photosynthetic capacity of tomato plants grown in a semi-closed greenhouse using temperature response models of plant photosynthesis by calculating the ribulose 1,5-bisphosphate carboxylase/oxygenase maximum carboxylation rate (V_cmax), maximum electron transport rate (J_max), thermal breakdown (high-temperature inhibition), and leaf respiration to predict the optimal conditions of the CO₂-controlled greenhouse, for maximizing the photosynthetic rate. Gas exchange measurements for the A-C_i curve response to CO₂ level with different light intensities {PAR (Photosynthetically Active Radiation) 200µmol·m^-2·s^-1 to 1500µmol·m^-2·s^-1} and leaf temperatures (20℃ to 35℃) were conducted with a portable infrared gas analyzer system. Arrhenius function, net CO₂ assimilation (A_n), thermal breakdown, and daylight leaf respiration (R_d) were also calculated using the modeling equation. Estimated J_max, A_n, Arrhenius function value, and thermal breakdown decreased in response to increased leaf temperature (> 30℃), and the optimum leaf temperature for the estimated J_max was 30℃. The CO₂ saturation point of the fifth leaf from the apical region was reached at 600ppm for 200 and 400µmol·m^-2·s^-1 of PAR, at 800ppm for 600 and 800µmol·m^-2·s^-1 of PAR, at 1000ppm for 1000µmol of PAR, and at 1500ppm for 1200 and 1500µmol·m^-2·s^-1 of PAR levels. The results suggest that the optimal conditions of CO₂ concentration can be determined, using the photosynthetic model equation, to improve the photosynthetic rates of fruit vegetables grown in greenhouses.

• Molecules and Cells
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• v.20 no.1
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• pp.69-73
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• 2005

The flavonoid, quercetin, is a low molecular weight substance found in apple, tomato and other fruit. Besides its antioxidative effect, quercetin, like other flavonoids, has a wide range of neuropharmacological actions including analgesia, and motility, sleep, anticonvulsant, sedative and anxiolytic effects. In the present study, we investigated its effect on mouse 5-hydroxytryptamine type 3 ($5-HT_{3A}$) receptor channel activity, which is involved in pain transmission, analgesia, vomiting, and mood disorders. The $5-HT_{3A}$ receptor was expressed in Xenopus oocytes, and the current was measured with the two-electrode voltage clamp technique. In oocytes injected with $5-HT_{3A}$ receptor cRNA, quercetin inhibited the 5-HT-induced inward peak current ($I_{5-HT}$) with an $IC_{50}$ of $64.7{\pm}2.2{\mu}M$. Inhibition was competitive and voltage-independent. Point mutations of pre-transmembrane domain 1 (pre-TM1) such as R222T and R222A, but not R222D, R222E and R222K, abolished inhibition, indicating that quercetin interacts with the pre-TM1 of the $5-HT_{3A}$ receptor.

• Food Science and Preservation
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• v.19 no.1
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• pp.47-53
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• 2012

UV light irradiation is known to give beneficial effects on fresh produce preservation. A container system equipped with UV-LED was fabricated for storing cherry tomatoes under computer-controlled conditions of intermittent on-off cycles (1 hour on/1 hour off). Wavelength (365 and 405 nm) and physical location of the LED (2 and 5 cm above fruit) were studied as variables affecting the respiration, ethylene production and quality preservation of the fruits at 10 and $20^{\circ}C$. 365 nm wavelength gave much higher radiation intensity than 405 nm, and intensity on surface decreased in inverse proportion to square of distance from LED. When compared to non-irradiated control, UV-LED irradiation decreased the respiration by 5-10% at $10^{\circ}C$ while there was no obvious effect at $20^{\circ}C$. Ethylene production was reduced when the fruits were placed at 5 cm distance, while there was no significant difference from control at 2 cm location. The reduction of ethylene production at 5 cm was more pronounced at $20^{\circ}C$. UV-LED irradiation was shown to have delayed increase or lower concentration in carotenoids compared to control treatment. Any negative effect of UV-LED irradiation on ascorbic acid content and firmness was not observed.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.341-345
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• 2019

Ethyl formate (EF) is a rapid kill, environmentally safe, and low mammalian toxicity fumigant, registered to disinfest quarantine insect pests from imported agricultural products. A new concept for controlling insect pests of agricultural crops was tested in a fumigation chamber with EF. Control efficacy of and phyto-toxicity due to EF fumigation were evaluated against four pests (Thrips palmi, Bemisia tabaci, Myzus persicae, and Tetranychus urticae) and on seedlings of four fruit vegetables (FVs; yellow melon, cucumber, tomato, and pepper). Ethyl formate fumigation at a dose of 1.5 g m^-3 for 12 h produced >93.3% mortality in T. palmi, B. tabaci, and M. persicae. However, T. urticae was tolerant to fumigation, showing only 20% mortality at 2.0 g m^-3. In terms of concentration × time (CT) products, at least 8.9 g·h m^-3 CT at 20 ± 1.5℃ was needed to achieve > 90% mortality against the three susceptible insect pests. Fumigation at 1.5 g m^-3 for 12 h caused no phyto-toxicity to any of the four FV seedlings. Ethyl formate application, as a new disinfestation method in greenhouses, could be an alternative to reduce the use of conventional insecticides. However, further studies are needed to determine the efficacy of this method at different pest developmental stages and in different greenhouse environments. Additionally, research is needed to elucidate the phyto-toxicity of EF application at different growing stages of a wide variety of crops.

• Korean journal of applied entomology
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• v.59 no.1
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• pp.55-64
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• 2020

Smart greenhouses are primarily used for growing fruits and vegetables, such as sweet peppers, tomatoes, strawberries. Although the number of smart greenhouses has been increasing exponentially, no studies have been performed to evaluate the state of smart greenhouses in Korea. Therefore, this study was conducted to determine current state of smart greenhouses with regard to greenhouse specifications, crop growing methods, pests, and user satisfaction in Korea. Contact information for smart greenhouses was provided by the officials of local agricultural research and extension services. This survey was conducted by visiting each greenhouse. Results showed that approximately 50% of surveyed smart greenhouses were between 3,300 ㎡ and 6,600 ㎡. The most frequently chosen method for pest control was chemical pesticides (97.1%). Powdery mildew and gray mold comprised 54.4% and 33.8% of the crop diseases, respectively. All tomato greenhouse farmers considered whiteflies the most problematic pest. In contrast, 76.5% and 70.6% of sweet pepper farmers believed thrips and aphids posed significant threats, respectively. The mean satisfaction score was 7.5 out of 10 points, with 10 being "extremely satisfied". These results will aid in decision making with respect to the management of current smart greenhouses and the design of future smart farms in Korea.

• Journal of Bio-Environment Control
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• v.12 no.4
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• pp.259-265
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• 2003

The physiological changes and antioxidant enzyme activities of plug seedlings irradiated with 4 kJ${\cdot}m^{-2}{\cdot}d^{-1}$ UV-B or sprayed growth inhibitors of 50 ${\cdot}L^{-1}$ diniconazole and 500 mg${\cdot}L^{-1}$ hexaconazole for retarding the overgrowth of cucumber, tomato and hot pepper seedlings in summer season were investigated. Photosynthetic rate just after UV-B irradiation was significantly low but recovered to the level of non-treated seedlings 10 days after IV-B irradiation. And photosynthetic rate of chemical-sprayed seedlings was slightly lower in tomatoes but not different in cucumbers and peppers, compared with non-treated seedlings. Cholrophyll contens in the leaves showed no difference among treatments. Anthocyanin contents in the leaves of UV-B-irradiated seedlings were higher and no difference inchmical-sprayed seedlings, compared with non-treated seedlings. the activites of SOD(superoside dismutase), CAT )catalase), and POD(perosidase) of UV-B-irradated seedlings were higher thatn those of the non-irradiated seedlings just after UV-B irradiation. However. 10 days after UV-B irradiation, the activities were decreased to half of the value just after UV-B irradiation Whereasd the activies of chemical-sprayed seedlings were slightly higher than those of non-treated ones but lower than those of UV-B-irradiated one.

• Journal of Plant Biotechnology
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• v.45 no.3
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• pp.155-170
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• 2018

In this paper, mechanisms of gene editing technologies including ZFN, TALENS and CRISPR were briefly discussed with mutual advantages and disadvantages. Classification criteria of gene edited, site-directed mutagenesis (SDN) crops for regulatory purpose were also discussed. The number of studies using CRISPR technology was high and studies conducted on Arabidopsis thaliana and rice were highest, followed by tobacco, tomato, wheat, and corn. It has been applied to a variety of plants such as other grain crops, flower crops, vegetable crops, and fruit trees. The number of studies focused on practical application or commercialization in the future were also increasing yearly, and the scope of studies also expanded to include research on metabolic engineering for mass production of useful proteins or substances, development of disease resistant crops against viruses, bacteria, and fungi, abiotic environmental stressresistant crops, and increased yields. In addition to this, it was revealed that application range is becoming more diversified, including the development of parthenocarpic tomatoes, hybrid rice lines using male sterility and increased shattering resistance Brassica napus. It was also revealed that the number of CRISPR gene edited crops permitted by the USDA(APHIS) increases yearly, to be released in the international seed market soon.

• Journal of Food Hygiene and Safety
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• v.15 no.2
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• pp.95-100
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• 2000

The effect of natural foods, utilizing the extracts or juices of teas(Green tea; Camellia sinesis, Du'chung; Eucommia ulmoides Oliver), medicinal plants(Eu sung cho; Houttuynia cordata Thunb, Sam back cho; Saurus Chinensis, Baek hwa sa seal cho; Oldenladia diffusa Roxb.) seaweeds(Laver; Porphyra tenera, Sea mustard; Undaria pinnatifida, Sea staghorn; Condium fragile) and vegetables(Sweet pepper; Capsicum annuum var. angulosum, Kale; Brassia oleracea var.. acephala, Cucumber; Cucumis sativus, Onion; Allium cepa) and fruits(Tomato; Lycopericon esculentum, Maesil; Prunus mume, Plum; Prunus saticina and Grape; Vitis spp.)on the inhibition of N-Nitrosodimethylamine(NDMA) formation was investigated from the various conditions. The inhibition effect was observed in vitro using the reaction fluids of pH 1.2, 4.2 and 6.0. From the teas and medicinal plants, there was a positive response of NDMA formation; however, From the seaweed extracts, there was a negative response of the inhibition effect of NDMA formation, and as the pH of reaction fluids and the amount of materials increase, the inhibition of NDMA formation was strengthened. The inhibition ratios by the level of pH are as follows: under pH 1.2 vegetable juice were 57.6∼99.7% and fruits were 35.9∼99.7%; under pH 4.2 vegetable juice were 55.0∼97.5% and fruits were 21.3∼96.8%. All of the materials observed has been proved and shown the inhibition effect of NDMA formation.