• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.230-233
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• 2011

We collected and examined germplasm resources of lettuces, edible chrysanthemums and mallows for organic farmers. We found that 3 genotypes (OL-51, OL-52, and OL-63) are suitable for organic cultivation. The main use of treatment for grey mold among eco-friendly pest control methods is helpful to increase efficiency of seed-gathering after collecting and evaluating a total of 64 kinds of lettuces-collected 43 South Korea local varieties, 8 kinds cultivated by the Highland Agriculture Research Center, 4 kinds of cultivated lettuces, and 9 kinds for sales- to choose appropriate kinds of lettuces for organic cultivation in South Korea. We chose those with more than 300 leaves (OC-18, OC-44, and OC-51) after evaluation of yield characteristics of a total of 62 edible chrysanthemums. We covered each genotype of seed of edible chrysanthemums when gathering the seeds by ourselves so as not to decrease the purity of each genotype. We chosed OM-38, OM-39, and OM-40 for their yield performance and germination rates among the total 41 genotypes of mallows. We selected 9 genotypes of lettuces, editable chrysanthemums and mallows with possibility of organic cultivation and found that they can be used permanently through self seed-gathering on organic farms.

• Food Science and Preservation
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• v.14 no.4
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• pp.345-350
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• 2007

Shelf-life and quality changes of four leaf lettuce cultivars packaged and stored at four different temperatures (0, 8, 16 and $24^{\circ}C$) were evaluated. Leaf lettuces were packaged in non-perforated polypropylene film (thickness 0.05 mm) bags. Weight loss, respiration rate, freshness degree, pigment content, and surface color were determined. At the storage temperature of $0^{\circ}C$, the weight loss, degree of freshness, pigment content, and change of surface color on packaged leaf lettuces showed no significant difference when compared with all other leaf lettuces. Meanwhile, an increase in storage temperature was observed with the quality changes of each flesh leaf lettuce. The leaf lettuces under storage conditions at $24^{\circ}C$ showed a difference in weight loss of the different types of leaf lettuces during a short storage period. However, there was no clear tendency in weight loss in different types of leaf lettuces as compared with each storage temperature. The rate of respiration and the contents of pigments in the four types of leaf lettuces also showed significant difference as the storage temperature increased.

• Food Science and Preservation
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• v.24 no.2
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• pp.159-167
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• 2017

This study was investigated the effects of maintaining the freshness and stabilization of supply and demand for lettuce (Lactuca sativa L.) by packaging methods in summer. Post-harvest lettuces were packaged by corrugated box, polypropylene (P) box, and individual wrapping using polyvinyl chloride (PVC) film. Then, the lettuce samples were stored at $2^{\circ}C$ and evaluated the change of quality during storage. The lettuces wrapped individually with PVC film had lower weight loss rate, color change, and browning index compared to lettuces packaged by corrugated box and P box. The SPAD value and hardness were higher in lettuces wrapped individually with PVC film than other packaging methods. The lettuces wrapped individually with PVC film were showed the highest total phenolic contents and DPPH radical scavenging activity, but there were no significantly differences by packaging methods. The lettuces packaged by corrugated box were showed the inside browning after 14 days. However, the lettuces wrapped individually with PVC film were showed the best appearance. Therefore, the packaging method of wrapped individually with PVC film were effective in maintaining the freshness during 21 days and helpful for the stabilization of supply and demand for lettuce in summer.

• Food Science and Preservation
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• v.15 no.5
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• pp.630-634
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• 2008

The effect of packaging methods on the quality characteristics of leaf lettuces was studied during storage at low temperature. Using five commercial packaging types: non-perforated PP (polypropylene) film bags, PP film roll, perforated PP film bags, PET (polyethyleneterephthalate) trays, and micro-perforated LDPE film bags, changes in color, respiration rate, and weight loss of leaf lettuces were investigated. Packaging in non-perforated PP film bags minimized color change and weight loss during storage. The leaf lettuces packaged in non-perforated PP film bags, among the five packaging choices, showed good external appearance and offered the greatest sale potential in the domestic market. However, there were no clear differences in the respiration rates of lettuces packed in various ways. The PET tray afforded very good protection of leaf lettuces from physical damage. The results indicate that the marketability of lettuces may be directly affected by the packaging modes employed, and that the optimal packaging may be non-perforated PP film bags; these keep lettuces fresh during low-temperature storage.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.6-12
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• 2012

Early growth, pigmentation, protein content, and phenylalanine ammonia-lyase (PAL) activity of red curly lettuces (Lactuca sativa L.) grown under different lighting conditions were investigated. Fluorescent lamps (control), blue, red, and blue plus red light-emitting diodes (LEDs) were used as light sources for 10 days. An equal proportion (1:1) of blue and red LEDs was used in the mixed radiation condition. Compared with the control, monochromic red or blue lighting increased fresh and dry weights of 'Ttuksum' and 'Jaju' lettuces. Anthocyanin synthesis was also significantly promoted by the mixed radiation of blue and red LEDs. The mixed radiation also increased the protein content and PAL enzyme activity of 'Ttuksum' leaves by about 200% compared to other treatments. Anthocyanin content was the highest in lettuces subjected to the mixture radiation of blue and red light treatment, while anthocyanin synthesis was inhibited by monochromic red light. The results of the present study indicate that growth and pigment synthesis in lettuces are significantly enhanced by exposure to mixed radiation from blue and red LEDs.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.70-78
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• 2013

Rhizoctonia solani and Fusarium oxysporum cause yield losses in numerous economically important crops. To develop a bio-control agent, cell free extracellular compounds (ECs) of 5 bacterial strains Burkholdria sp. L1, Pseudomonas sp. L4, Pseudomonas chlororaphis VN391, Bacillus subtilis VN21 and Enterobacter sp. VN99 from Vietnamese fields, which reduced levels of R. solani root rot in lettuces and F. oxysporum root rot in tomatoes, were investigated. In a growth chamber, ECs of all antagonists markedly enhanced the biomass of lettuces (10 to 14.1%) and tomatoes (11.38 to 13.88%). In greenhouses, the disease's severity on both crops treated with ECs of the antagonists was reduced significantly and biomass losses in the plants decreased markedly. The reduction level of R. solani root rot in lettuces was 75, 66.7, 50, and 16.7% by ECs of strains L1, L4, VN21 and VN391, respectively. The biomass of lettuces increased markedly by 29.13%, 21.67%, and 23.4% by ECs of strains L1, L4 and VN21, respectively. Similarly, the reduction levels of F. oxysporum root rot in tomatoes was 76.3, 75, 41.7 and 25% by ECs of strain L1, L4, VN21 and VN391, respectively, and the biomass was significantly enhanced by 14.42, 12.7 and 13%, respectively. The ECs of strain L1 exhibited the most effective bio-control agents to suppress R. solani and F. oxysporum.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.700-705
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• 2013

The purpose of this study is to investigate the quality changes and contamination of microorganisms such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in cherry tomatoes and head lettuces during the storage of different temperatures and periods. This study determines the pH levels, color changes and the growth patterns of microorganisms in cherry tomatoes and head lettuces during storage of 14 days at $5^{\circ}C$, $10^{\circ}C$ and $15^{\circ}C$. According to the results, the pH level is being reduced with storage periods in cherry tomatoes and head lettuces. The $L^*$, $a^*$ and $b^*$ values of cherry tomatoes are decreased with storage period, whereas the $a^*$ and $b^*$ values have increased with storage of the head lettuces. With regards to the types of microorganisms, the aerobic count plate (ACP), coliform count (CC), mold and yeast are being detected when cherry tomatoes and head lettuces are stored at $5^{\circ}C$, $10^{\circ}C$ and $15^{\circ}C$, whereas the S. aureus and E. coli are not being detected at 14 days of storage. The ACP, CC and yeast of cherry tomatoes increase with storage period, whereas the mold of cherry tomatoes was decreased after 14 days of storage. For the head lettuces, APC and CC have significantly increased with storage, whereas the mold stored at $5^{\circ}C$, $10^{\circ}C$ and $15^{\circ}C$ decreased after 21 days of storage. From these studies, we can confirm that changes in quality characteristics and the types of microorganisms existed in cherry tomatoes and head lettuces during storage were the ACP, CC, mold and yeast, whereas the E. coli and S. aureus are not detected.

• Journal of Biosystems Engineering
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• v.32 no.4
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• pp.256-262
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• 2007

Image processing systems have been used to measure the plant parameters such as size, shape and structure of plants. There are yet some limited applications for evaluating plant colors due to illumination conditions. This study was focused to present adaptive methods to analyze plant leaf color regardless of illumination conditions. Color patches attached on the calibration bars were selected to represent leaf colors of lettuces and to test a possibility of health monitoring of lettuces. Repeatability of assigning leaf colors to color patches was investigated by two-tailed t-test for paired comparison. It resulted that there were no differences of assignment histogram between two images of one lettuce that were acquired at different light conditions. It supported that use of the calibration bars proposed for leaf color analysis provided color constancy, which was one of the most important issues in a video color analysis. A health discrimination equation was developed to classify lettuces into one of two classes, SOUND group and POOR group, using the machine vision. The classification accuracy of the developed health discrimination equation was 80.8%, compared to farmers' decision. This study could provide a feasible method to develop a standard color chart for evaluating leaf colors of plants and plant health monitoring system using the machine vision.

• Journal of Environmental Science International
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• v.33 no.1
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• pp.59-65
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• 2024

The objective of this study were to assess rooftop urban agriculture and analyze the differences in soil, growth, physiology, and productivity to elucidate the effect of companion planting with various plants, including lettuce (Lactuca sativa), rosemary (Salvia rosmarinus), marigold (Tagetes patula), Korean perilla (Perilla frutescens), and garlic chives (Allium senescens). Measurements were taken every other week from May to August 2023, totaling eight measurement. Regarding the characteristics of the soil planted with lettuce and aromatic plants, the combined planting of lettuce and garlic chives created a favorable soil environment for plant growth. Consequently, the best growth was observed when lettuce and garlic chives were companion planted. Companion planting of lettuce and garlic chives appears to be the most efficient concerning growth and physiology. The productivity of companion planting lettuce and aromatic plants also showed high-quality lettuce when lettuces and garlic chives were companion planted. Therefore, companion planting of lettuces and garlic chives in rooftop urban agriculture is suitable for growth, physiology, and productivity.

• Parasites, Hosts and Diseases
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• v.21 no.1
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• pp.105-110
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• 1983

A survey on vegetables, which consisted of lettuce (Lactuca sativa) , young radish (Raphanus sapiwus), and chinese cabbage (Brassica pekinensis) collected from 6 markets in the Taegu city, was conducted for the discovery of helminth eggs and larvae, from July, 1982 to June, 1983. The results were compared with the data obtained from vegetables collected at the same markets by Lee (1969) and Choi and Lee (1972). Both sides of vegetable leaves were washed carefully with a hard brush, and the species of parasites and the mean number of parasites per 200g of vegetable were determined. When vegetable were examined, 4 species of parasite eggs (ascarid, Trichostrongylus, liver fluke, and hookworms) and 2 larvae (filariform and rhabditoid larvae) were found. Of the parasite discovered, ascarid egg was found to be highest (4.2%) , followed by hookworm egg (3.6%) . The mean number of ascarid egg per 200 grams of vegetable was 0.6 in young radishes, and 0.3 in both lettuces and and chinese cabbages. Similarly, the number of filariform larva of hookworm was 0.4 in young radishes, 0.3 in lettuces, and 0.1 in chinese cabbages, and the number of rhabditoid larva was 0.2 in young radishes, 0.1 in lettuces, and 0.05 in chinese cabbages. In the results obtained by Lee (1969) and Choi and Lee (1972) , the mean number of ascarid egg per 200 grams of vegetable was 7.5 in young radishes, 3.1 in lettuces, and 0.5 in chinese cabbages. By contrast, in the present study it was 0.6 in young radishes an 0.3 in both lettuces and chinese cabbages. These results suggest that there has been significant reduction in the incidence of parasite egg and larva on vegetable leaves during the past 10 years.