• Horticultural Science & Technology
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• v.34 no.4
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• pp.596-606
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• 2016

The growth and contents of anthocyanins and ascorbic acid in lettuce(Lactuca sativa L., 'Jeokchima') as affected by supplemental UV-A LED irradiation under different light quality and photoperiod conditions were analyzed in this study. Five light qualities, namely B (blue LED), R (red LED), BUV (blue LED+UV-A LED), RUV (red LED+UV-A LED) and Control (white fluorescent lamps) with photoperiods of 12/12 hours (day/night), 16/8 hours, or 20/4 hours were provided to investigate the effects of light quality and photoperiod on the growth and accumulation of anthocyanins and ascorbic acid in lettuce leaves. As measured 28 days after transplanting, the number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce were significantly affected by light quality and photoperiod. The number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce grown under R treatment increased with increasing light period. By contrast, leaf development was inhibited, but chlorophyll content increased, under B treatment. Supplemental UV-A irradiation significantly decreased leaf length, leaf width, leaf area and shoot fresh weight. Anthocyanins in lettuce increased significantly with decreasing dark period under B treatment. A synergistic effect of supplemental UV-A LED irradiation on anthocyanins accumulation was found for lettuce leaves grown under R treatment but not B treatment. Ascorbic acid in lettuce was greatly affected by photoperiod. Ascorbic acid content at BUV and RUV treatments increased by 20-30% compared to without UV-A LED irradiation. From these results, it was concluded that growth and contents of anthocyanins and ascorbic acid in lettuce are significantly affected by supplemental UV-A LED irradiation. The results obtained in this study will be informative for efforts to improve the nutritional value of leafy vegetables grown in plant factories.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.333-342
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• 2010

For the energy-saving production of fresh vegetables in poor environment such as the Antarctic, a container-type plant factory was designed and developed. To maximize space usage of the 20 feet container ($L5.9m{\times}W2.4m{\times}H2.4m$), a three-level hydroponic cultivation system was installed and the nutrient solution was supplied by bottom watering. Using this system, 3 lettuce cultivars were grown under different the light source (light intensity). After 2 weeks from the transplanting, fluorescent lamp ($145\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) showed the best fresh weight of top part and leaf area. However, After 4 weeks, fluorescent lamp plus metal halide lamp ($150\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) led to the optimum growth of the each lettuce cultivar. The cultivar, 'Cheongchima', showed the best fresh weight of top part and leaf area, followed by 'Jeokchukmyeon' and 'Lollo rosa'. The chlorophyll concentrations (SPAD) showed no significant difference among the sources of lights. However, 'Cheongchima' showed relatively high chlorophyll concentration. With the above results, we found that the growth of lettuce is depend on light intensity and even at same intensity, the growth is different among the cultivars. Therefore, the selection of optimum cultivar should be considered in the plant factory system that has only weak light density.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.335-344
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• 2021

BACKGROUND: Cyantraniliprole is a systemic diamide insecticide that has been used to control lepidopteran pests in agriculture. Cyantraniliprole has become an issue due to its potentiality of unexpectable contamination in rotational crop cultivation. Thus, studies on the evaluation of cyantraniliprole translocated from soil into rotational crops are required. METHODS AND RESULTS: Cyantraniliprole was treated at a yearly maximum application level onto bare soil under greenhouse conditions in two geographically different regions. Lettuce was transplanted and spinach and radish were sown onto the soil 30 and 60 days-plant back intervals (PBIs) after cyantraniliprole treatment. The QuEChERS method was modified and coupled with LC/MS/MS analysis to determine the residues of cyantraniliprole in soil and plant samples. The methods for sample preparation and instrumental conditions were validated to meet the criteria of Codex guidelines and were successful to determine cyantraniliprole quantitatively and qualitatively in the samples. Cyantraniliprole residues in lettuce samples were 0.01 mg/kg for PBI 60 and 0.02 mg/kg for PBI 30, respectively. The residues in spinach samples were 0.01 mg/kg for PBI 60 and 0.01~0.02 mg/kg for PBI 30, respectively. Less than limit of the quantitation (LOQ) level (0.01 mg/kg) of cyantraniliprole was observed in radish samples. The residues in the plant samples were found as the levels less than maximum residue limit (MRL) for leafy and root vegetables. CONCLUSION(S): This study suggests PBI 30~60 days for rotational cultivation of lettuce, spinach and radish in greenhouse soil treated with cyantraniliprole at a yearly maximum application level.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.171-174
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• 2001

Solid phase micro-extraction (SPME), a solvent-free, rapid and inexpensive method for the extraction of organic compounds from aqueous sample matrices, was evaluated for determination of the 120 pesticides in vegetables such as crown daisy, perilla leaf, leafy lettuce and to mato. The analysis conditions were chosen for the SPME method: 15 min of immersion of the PDMS fiber in 10 ml of the solution with stirring at 1,000 rpm. The recovery tests were carried out in triplicate. The range of recoveries was 0-142% for organochlorine pesticides and $4.9\sim200\%$ for organophosphorus pesticides. The recoveries were very low in the pesticide groups with low solubility in water. The recoveries became lower in proportion to the interference materials in vegetables. The recovery in tomato was relatively higher than that in perilla Ie af and crown daisy. The recovery values obtained by SPE and SPME were compared. In leaf y lettuce, recovery obtained by SPE method ranged from $58.1\%\;to\;136.1\%$ and recovery by SPME ranged from $9.6\%\;to\;176.3\%$ In organophosphorus pesticides. The recovery in SPME method was satisfactory with $136\%$ for ethoprophos, $119\%$ for methidathion and $113\%$ for diazinon. Meanwhile, recovery of EPN, phenthoate and 2,4-DDT revealed relatively low value of $38\%,\;41\%\;and\;3.4\%,$ respectively. However, most of pesticides applied to SPME method sho wed constant recovery and precision. From these results, it can be concluded that solid phase micro-extraction might be an appropriate method for the screening test of pesticides in vegetables.

• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.384-393
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• 2021

Recently, due to environmental and toxicity issues, there has been increasing attention on research regarding natural products that can reduce the use of chemical fertilizers. Wood extracts derived from the biorefining process contain various fertilizer ingredients. HPLC analysis revealed that wood extract contains approximately 5.2% hemicellulosic sugar. The growth of lettuce (Lactuca sativa) upon treatment with wood extract (extract obtained from steam-exploded pine) or water-soluble fertilizers containing different nutrients was analyzed in this study. After two weeks, the growth characteristics of lettuce as affected by wood extract or water-soluble fertilizers were significantly different. The effect of water-soluble fertilizers containing ascorbic acid, magnesium sulfate, citric acid, potassium nitrate, amino acids, or seaweed extract was less desirable than that of wood extracts regarding plant height (18.6 cm), number of leaves (10), leaf length (14.1 cm), shoot fresh wight (9.8 g/plant), root fresh weight (0.8 g/plant) and shoot dry weight (0.6 g/plant). The plant height, number of leaves, leaf length, shoot fresh wight, root fresh weight, shoot dry weight of water-soluble fertilizers containing wood extract were significantly different compared to the control (plant height :13.5 cm, number of leaves : 7, leaf length : 9.4 cm, shoot fresh wight : 5.3 g/plant, root fresh weight : 0.7 g/plant, shoot dry weight : 0.4 g/plant, root dry weight : 0.07 g/plant). From these results, it was concluded that wood extract can be used as a potential water-soluble fertilizer to increase the yield of leafy vegetables.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.381-393
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• 2010

In order to monitor the residual characteristics of the pesticides in leafy vegetables selling at wholesale markets and traditional markets in Cheongju, a total of 180 samples of 15 leafy vegetables, such as broccoli, celery, chard, chicory, Chinese vegetable, Chwinamul, crown daisy, Korean cabbage, leek, lettuce, perilla leaves, Shinsuncho, spinach, welsh onion and young radish, were purchased from the wholesale markets and traditional markets in June and August in 2010 and the pesticide residues in them were analyzed by multiresidue analysis method using GLC, HPLC and GC-MSD. Seven pesticides were detected from 12 samples out of total 180 samples collected, representing detection rate was 6.7%. In case of the samples collected from markets in June, four pesticides including tefluthrin were detected from six samples and in case of the samples collected from markets in August, three pesticides including pendimethalin were detected from three samples. The MRL-exceeding rate of pesticides detected from leafy vegetables was 0.6%. The pesticide exceeded its MRL was azoxystrobin detected from crown daisy and many pesticides were not registered to the crops, excepting that azoxystrobin detected from Chwinamul and tefluthrin from leek. Estimated daily intakes (EDIs) of the pesticides detected from leafy vegetables were less than 7% of their acceptable daily intakes (ADIs), representing that residue levels of the pesticides detected were evaluated as safe.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.415-422
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• 2010

Two leaf lettuces, chicory, endive, edible chrysanthemum, and pak-choi were hydroponically cultured under root restricted conditions in a deep flow technique system and their growth and nutritional values were investigated. Cylindrical plastic tubes with 100 mm height and diameters of 20, 25 or 30 mm were used for root restriction. Growth of all species was retarded by 25-95% as the roots zone was restricted. Pak-choi and edible chrysanthemum showed greater reduction in growth as compared with chicory and endive. Percent dry matter, C/N ratio, and contents of total ascorbic acid and total anthocyanin increased in the root restricted treatments. Contents of P and K decreased in the root restricted treatments, while contents of Mg, Fe, Mn, and Zn were not consistent among the tested species. Optimized root volumes to improve the nutritional values and to reduce the growth retardation varied depending on species of leafy vegetables. Tubes of ${\Phi}25mm{\times}100mm$ and ${\Phi}30mm{\times}100mm$ were suitable for chicory, endive and lettuce, and edible chrysanthemum and pak-choi, respectively. Results indicate that nutritional values of hydroponically-cultured leafy vegetables can be improved by root restriction.

• Environmental Engineering Research
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• v.23 no.3
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• pp.271-281
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• 2018

To examine the feasibility of reuse of raw fishmeal wastewater, it was biodegraded by a microbial consortium in a $1-m^3$ reactor, and the final culture broth including mixed microbes was applied as biofertilizer to field cultivation of lettuce and Chinese cabbage. Moreover, economic analysis of the entire process was performed. A stable metabolism of organic matter degradation for 80 h with sufficient dissolved oxygen produced an amino acid content of 14.66 g per 100 g sample, along with increased cation and anion concentrations. The concentrations of N, P and K in the final culture broth were 2.26, 0.87 and 0.65%, respectively, while those of heavy metals were very low. In field cultivation of the two leafy vegetables, the biodegraded fishmeal wastewater showed better fertilizing ability than commercial fertilizers because of its high amino acid content. In addition, no external damage to leaves by the fertilization was observed. In economic analysis, the expected profitability from the practical reuse of raw fishmeal wastewater was estimated to be $491.68 per a single biodegradation, which corresponds to $25,567.36 per year. As a result, the complete reuse of fishmeal wastewater could be feasible and provide essential benefits.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.72-76
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• 2003

This study was conducted to estimate stimulation of plant growth of green and red leafy lettuces (Lactuca sutiva L. cv. Chungchima and Jugchima) at affected by covering method and time with protected film materials containing concentrated PO film and GA$_3$ foliar spray. Plants were covered with ‘Pasraido’ material from October 26 to November 31 (direct 1), from November 5 to November 31 (direct 2), or with a tunnel, or direct 2＋ tunnel. Mean air temperature and relative humidity under the covering were higher in direct and tunnel, direct and non-covering, in that order. The fresh weight and dry weight of red and green lettuces increased in direct and tunnel followed by direct 1, direct 2, tunnel and the control. GA$_3$ treatment promoted the growth in all covering methods, but decreased the chlorophyll contents. Fresh weight and dry weight were higher in red lettuce than in green lettuce in the control.

• Research in Plant Disease
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• v.13 no.3
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• pp.157-163
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• 2007

Hot water treatment that is the most appropriate seed disinfection method for organic vegetable farming was evaluated in this study. Among the leafy vegetable seeds lettuce that was the most sensitive to hot water was suitable to treat at $45^{\circ}C$ for 25 min, while Chinese cabbage and radish seeds were optimally treated at $50^{\circ}C$ for 25 min. The treatments resulted in similar or higher seed germination rate than non-treated seeds and promoted plant growth. In addition, fungi such as Alternaria, Aspergillus, Penicillium, or Mucor grown on the seeds were suppressed over 90% and the bacterial growth on lettuce seeds reduced 98.5% by the treatment. Among the fruit vegetable seeds pumpkin that was vulnerable to hot water was suitable to treat at $50^{\circ}C$ for 15 min, while cucumber and hot pepper seeds revealed optimum treatment at $50^{\circ}C$ for 25 min as chinese cabbage and radish. The treatment also showed similar or higher seed germination rate and growth than non-treated seeds. Furthermore, fungi such as Rhizopus, Aspergillus, Penicillium or Mucor grown on the seeds reduced from 72.0% to 95.4%. The bacterial growth on cucumber and red pepper seeds was suppressed from 65.5% to 86.0% by the treatment. Results indicated that the hot water treatment is practical for disinfection of organic vegetable seeds and the optimum temperature and soaking time varied among the seeds.