• The Korean Journal of Mycology
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• v.41 no.2
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• pp.118-126
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• 2013

The experiment was carried out to analyze the inhibition effect of plant pathogenic fungi and growth promotion activity induced by the bacterial strains isolated from peatmoss. Among the isolated bacterial strains, B10-2, B10-4, B10-5 and B10-6 which showed more than 30% inhibition rate against Botrytis cinerea and Rhizoctonia solani in vitro, were further analyzed in the greenhouse for the growth promotion activity on lettuce (Lactuca sativa), pak-choi (Brassica compestris L. ssp. chinensis) and Chinese cabbage (Brassica campestris L. ssp. pekinensis). The results showed the treatment of B10-4 on lettuce showed the highest growth promotion activity with the leaf area ($169.17cm^2$), fresh weight (leaf: 40.29 g, root: 8.80 g)and dry weight (leaf: 11.24 g, root: 4.17 g), which was about two folds as compared to control. On pak-choi, the growth promotion rate was the highest with the leaf area of $112.87cm^2$, leaf fresh weight of 60.70 g, root fresh weight of 3.37 g, leaf dry weight of 14.34 g, and root dry weight of 1.90 g. As a result of treatment of B10-13 on chinese cabbage, the growth promotion rate was the highest with the leaf area ($293.56cm^2$), fresh weight (leaf: 113.67 g, root: 2.40 g) and dry weight (leaf: 6.03 g, root: 0.53 g). The production of Indole Acetic Acid (IAA) and Indole-3-Butylic Acid (IBA) were also analyzed in these bacterial isolates. The IAA and IBA analyses were carried out in all bacterial isolates each day within the 5 days of incubation period. The highest production of IAA was observed with $112.57{\mu}g/mg$ protein in B10-4 after 3 days of incubation and IBA production was the highest in B10-2 with $58.71{\mu}g/mg$ protein after 2 days of incubation. Also, phosphate solubilizing activity was expressed significantly in B10-13 in comparison to that of other bacterial isolates. Bacterial identification showed that B10-2 was Bacillaceae bacterium and B10-5 was Bacillus cereus, B10-4 and B10-6 were Bacillus sp. and B-13 was Staphylococcus sp. by ITS sequence.

• Journal of Animal Environmental Science
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• v.15 no.1
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• pp.51-58
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• 2009

The compost leachate was dark-colored solution that leaches out of the bottom of the compost pile. The compost leachate was rich in nutrients and can potentially used in plant culture. In the organic production, commercial liquid fertilizer was used to insure the availability of nutrients during the formation of the yield. The cost of supplemental liquid fertilizer could be reduced by developing a fertilizer based on animal fertilizer. This experiment was conducted to investigate the effect of different combination of compost leachate and conventional inorganic solution in hydroponic culture for lettuce growth. Six different treatments were applied. The compost leachate(CL) and nutrient solution(NS) were mixed by six different mixing ratios of 0:100, 20:80, 40:60, 60:40%, 80:20 and 100%:0% based on nitrogen content. The chemical nutrient solution was the solution of National Horticulture Research Station for the growth of leaf lettuce. The concentration of nutrient solution was adjusted 1.5 mS/cm in EC. The compost leachate was low in phosphorus(P), calcium(Ca), magnesium(Mg), but rich in potassium(K). The plant height of lettuce treated with CL 20+NS 80% was similar with 100% NS of control plot. Plant height was highest in the plot of CL 20+NS 80%. The treatment of 100% compost leachate was lowest in the growth characteristics of leaf lettuce. Number of leaf was very low in 100% compost leachate compared with plot of chemical nutrient solution. In the beginning of growth stage, SPAD value was reduced in plot treated with CL100%, but CL20+NS80% plot was higher compared to 100% compost leachate. SPAD value of leaf lettuce leaves was decreased as the amount of CL was increased. The dry weight of lettuce were 107.4, 104.2g in plot of NS 100% and CL 20%+NS80%, respectively. The leaf number and plant weight were decreased at high application plots of compost leachate. The leaf lettuce showed lowest in the plot treated with 100% compost leachate, and the growth of lettuce severely decreased after application of 100% CL treatment. The results showed that compost leachate can be use as liquid fertilizer for the organic hydroponic production. The mixture solution of 20% of compost leachate and 80% of nutrient solution could be used as a nutrition solution in hydroponic culture of leaf lettuce. Our studies have shown that is possible to produce using compost leachate, although growth is slower than when using a conventional inorganic hydroponic solution.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.293-301
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• 2013

This study was carried out to investigate the pesticide residue pattern among different leafy vegetables applied with foliar spraying under greenhouse and to check extrapolating from some residue trial data to other minor crops. Leafy vegetables used in this study were: Mustard greens (Brassica juncea L.), Kale (Brassica oleracea L.), Dacheongchae (a kind of pak-choi (Brassica rapa subsp. chinensis L.)), Leaf broccoli (Brassica oleracea var alboglabra), Perilla leaf (Perilla frutescens (L.) Britton var. Frutescens), Leaf lettuce (Lactuca sativa L.), Swiss chard (Beta vulgaris L. subsp. vulgaris) and Red leaf chicory (Cichorium intybus L. var. foliosum Hegi). These are cultivated all year under indoor or outdoor and cut the leaf from plant continuously during harvest time. The amounts of pesticide deposit in/on the continuous harvesting leafy vegetables were affected by the ratios of leaf area to weight. Ratio of perilla leaf was the largest among crops as 58 $cm^2/g$. The residue levels of 7 pesticides in/on perilla leaf were the highest than those of other crops through the statistical analysis from zero day to fifth day after last application. The representative crop in 8 crops was perilla leaf selected based on the amounts of daily consumption and the high residues. This study suggest that the continuous harvesting leafy greens should be separated from the one time harvesting leafy vegetables for the pesticide recommendations because of different harvesting habits and pre-harvest intervals.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.399-401
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• 2015

This study investigated the plant growth promoting activity of geraniol on Chinese cabbage (Brasscia campestris ssp. Pekinensis Rupr.), Pak Choi (Brassica rapa L.), Crown daisy (Chrysanthemum coronarium L.), Iceberg lettuce (Lactuca sativa L.) and Leaf perilla (Perilla frutescens Britt.). Geraniol at 0.5 to $10mg\;L^{-1}$ promoted radical growth of Chinese cabbage Pak Choi, Crown daisy, Iceberg lettuce and leaf perilla by >30%. In the pot experiments, geraniol treatment at $20mg\;L^{-1}$ by drenching increased up to 190% of the aerial part growth promotion. By comparison, foliar application showed 124% promoting activity only at $100mg\;L^{-1}$.

• Economic and Environmental Geology
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• v.52 no.2
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• pp.129-139
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• 2019

This study investigates the spectral response of red lettuce (Lactuca sativa var crispa L.) to Zn concentration. The control group and the experimental groups treated with 1 mM(ZnT1), 5 mM(ZnT2), 10 mM(ZnT3), 50 mM(ZnT4), and 100 mM(ZnT5) were prepared for a pot experiment. Then, Zn concentration and spectral reflectance were measured for the different levels of Zn concentration in red lettuce. The Zn concentration of the control group had the range of 134-181 mg/kg, which was within the normal range of Zn concentration in uncontaminated crops. However, Zn concentration in the experimental group gradually increased with an increase in concentration of Zn injection. The spectral reflectance of red lettuce showed high peak in the red band due to anthocyanin, high reflectance in the infrared band due to the scattering effect of the cell structure, and absorption features associated with water. As Zn concentration in red lettuce leaves increased, the reflectance increased in the green and red bands and the reflectance decreased in the infrared band. The correlation analysis between Zn concentration and spectral reflectance showed that the reflectance of 700-1300 nm had a significant negative correlation with Zn concentration. The spectral band is a wavelength region closely related to the cell structure in the leaf, indicating possible cell destruction of leaf structure due to increased Zn concentration. In particular, 700-800 nm reflectance of the infrared band showed the strongest correlation with the Zn concentration. This study could be used to investigate the heavy metal contamination in soil around mining and agriculture area by spectroscopically recognizing heavy metal pollution of plant.

• Korean Journal of Organic Agriculture
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• v.7 no.1
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• pp.115-127
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• 1998

Under the visual judgement of consumers, to reduce nitrate intake through vegetables, this experimentation analyzed the content of nitrate, in heading leaf vegetables such as chinese cabbage(Brassica campestris L. ssp. perkinensis (Lour.) Rupr), cabbage(Brassica oleracea L. var. capitata) and lettuce(Lactuca sativa L.) by the leaf number. And the result is summarized as follows In the nitrate content change by the leaf number, the nitrate content is increased as it goes by from inner leaf to outer leaf and the nitrate content in leaf midrib is higher than that in leaf blade. In case of chinese cabbage, the nitrate content in the leaf midrib from the most inner leaf to the most outer leaf changed 40-3,177ppm and in the leaf blade it changed 40-2,887ppm. But the nitrate content in the leaf blade of cabbage from the most inner leaf to the most outer leaf changed 89~2,297ppm and in the leaf blade it changed 25~765ppm. In case of lettuce, the nitrate content change of the leaf midrib by the leaf position was 419~4,349ppm, and in the leaf blade it changed 260~2894ppm. It was conclude that the outer leaf of chinese cabbage, cabbage and lettuce should be removed to keep the lower nitrate intake by population before it is consumed.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.97-105
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• 2023

Concentration of nitrogen, one of the major elements, and ratio of two nitrogen forms (NH₄⁺ and NO₃^-) in the nutrient solution affect the quality and food safety of fresh vegetable produce. This study was conducted to find an appropriate strength and NH₄⁺:NO₃^- ratio of a nutrient solution for growth and development of a Romaine lettuce (Lactuca sativa L. var. longiflora) 'Caesar Green', a representative leafy vegetable, grown in a home hydroponic system. In the first experiment, plants were grown using three types of nutrient solution: A commercial nutrient solution (Peters) and two strengths (GNU1 and GNU2) of a multipurpose nutrient solution (GNU solution) developed in a Gyeongsang National University lab. Plants grown with the GNU1 and GNU2 had greater shoot length, leaf length and width, and biomass yield than Peters. On the other hand, the root hairs of plants grown with Peters were short and dark in color. Tissue NH₄⁺ content in the Peters was higher than that of the GNU1 and GNU2. The higher contents of NH₄⁺ in this solution may have caused ammonium toxicity. In the second experiment, eight treatment solutions, combining GNU1 and GNU2 solutions with four ratios of NO₃^- :NH₄⁺ named as 1, 2, 3 and 4 were used. Both experiments showed more growth in the GNU2 group, which had a relatively low ionic strength of the nutrient solution. The growth of Romaine lettuce showed the greatest fresh weight along with low tissue NO₃^- content in the GNU2-2. This was more advantageous in terms of food safety in that it suppressed the accumulation of surplus NO₃^- in tissues due to the low ionic trength of the GNU2 subgroup. In addition, this is preferable in that it can reduce the absolute amount of the input of inorganic nutrients to the nutrient solution.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.50-54
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• 2001

Effect of NO$_3$:NH$_4$ratio and pH of nutrient solution on nitrate content of leaves was investigated for leaf lettuce(Lactuca sativa L.) grown by a deep flow technique. Ratios(in me.L$^{-1}$ ) of NO$_3$:NH$_4$tested were 12:1, 10:3 and 8:5. The treatment of 8:5 NO$_3$:NH$_4$ratio had two solutions, one with uncontrolled pH and the other with automatically controlled pH. Solution pH continuously increased in 12:1 NO$_3$:NH$_4$treatment. Solution pH decreased gradually more as NH$_4$ratio increased. Treatment of 8:5 NO$_3$:NH$_4$with automatic pH control satisfactorily maintained the solution pH in the range of pH 5.5-6.0. Nitrate content in leaves was the greatest in treatment of 12:1 NO$_3$:NH$_4$ and the least in treatment of 8:5 NO$_3$:NH$_4$with automatic pH control. Fresh weight decreased in treatments of 10:3 and 8:5 NO$_3$:NH$_4$, whereas it increased in treatments of 12:1 and 8:5 NO$_3$:NH$_4$with pH control. It was concluded that the growth and leaf nitrate content were the greatest in high NH$_4$treatment with automatic pH control.

• Korean Journal of Organic Agriculture
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• v.13 no.4
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• pp.413-422
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• 2005

This study was carried out to investigate the effect of different mixture ratios of vermicasts on the growth of leaf beet(Beta vulgaris var. cicla), young radish (Raphanus sativus L), spinach(Spinacia oleracea) and lettuce(Lactuca sativa) The mixture of ratios of vermicast(fermented pig manure with sawdust) and peatmoss were 100%+0%, 60%+40%, 40%+60% and 0%+100%(control), respectively. The bulk density, particle density, pH, electrolytic conductivity, ash, total nitrogen, cation exchange capacity, available phosphorous and exchangeable cations increased significantly compared to those grown in the 100% of peatmoss(control). The significantly higher values of plant length, leaf area, shoot dry weight, root weight, root length and biological yield obtained were $40{\sim}100%$ and 40% of vermicast in leaf beet and lettuce, respectively. The young radish and spinach showed that significantly differences of shoot dry weight, root weight and biological yield in the mixture ratios of vermicast were $40{\sim}60%$ and 40% in young radish and spinach, respectively.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.182-187
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• 2013

In closed plant production system like plant factory, changes in environmental factors should be identified for conducting efficient environmental control as well as predicting energy consumption. Since high relative humidity (RH) is essential for crop production in the plant factory, transpiration is closely related with RH and should be quantified. In this study, four varieties of lettuces (Lactuca sativa L.) were grown in a plant factory, and the leaf areas and transpiration rates of the plants according to DAT (day after transplanting) were measured. The coefficients of the simplified Penman-Monteith equation were calibrated in order to calculate the transpiration rate in the plant factory and the total amount of transpiration during cultivation period was predicted by simulation. The following model was used: $E_d=a*(1-e^{-k*LAI})*RAD_{in}+b*LAI*VPD_d$ (at daytime) and $E_n=b*LAI*VPD_n$ (at nighttime) for estimating transpiration of the lettuce in the plant factory. Leaf area and transpiration rate increased with DAT as exponential growth. Proportional relationship was obtained between leaf area and transpiration rate. Total amounts of transpiration of lettuces grown in plant factory could be obtained by the models with high $r^2$ values. The results indicated the simplified Penman-Monteith equation could be used to predict water requirements as well as heating and cooling loads required in plant factory system.