• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.291-296
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• 1997

The dietary fiber contents of seaweeds including Drown algae (Undaria pinnatifida, Laminaria japonica, Hizikia fusiforme), red algae (Gelidium amansii, Gracilaria verrucosa) and green algae (Ulva lactuca) and the extraction condition of the fiber was investigated. The dietary fiber contents of Undaria pinnatifida, Laminaria japonica, Hizikia jusiforme, Gelidium amansii, Gracilaria verrucosa and Ulva lactuca were $47.2\%,\;50.7,\;42.6\%,\;48.8\%,\;44.5\%\;and\;40.0\%$, respectively. It was effective to extract soluble dietary fiber with sodium salts such as disodium carbonate and disodium EDTA in brown algae. In red algae, it was effective to extract soluble dietary fibre with disodium EDTA. Also, the extraction time and temperature affected the yields of dietary fiber.

• Journal of Environmental Science International
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• v.20 no.12
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• pp.1509-1519
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• 2011

The protective effect of nitric oxide (NO) on the antioxidant system under paraquat(PQ) stress was investigated in leaves of 8-week-old lettuce (Lactuca sativa L.) plants. PQ stress caused a decrease of leaf growth including leaf length, width and weight. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated PQ stress induced growth suppression. SNP permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem II than in non-treated controls under PQ exposure, suggesting that NO has protective effect on chloroplast membrane in lettuce leaves. Flavonoids and anthocyanin were significantly accumulated in the leaves upon PQ exposure. However, the rapid increase of these compounds was alleviated in the SNP treated leaves. PQ treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide ($H_2O_2$) in the leaves, while SNP prevented PQ induced increase in malondialdehyde (MDA) and $H_2O_2$. These results demonstrate that SNP serves as an antioxidant agent able to scavenge $H_2O_2$ to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, superoxide dismutase (SOD) and catalase (CAT) in lettuce leaves in the presence of NO donor under PQ stress were higher than those under PQ stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), a specific NO scavenger, to the lettuce leaves arrested SNP mediated protective effect on leaf growth, photosynthetic pigment and antioxidant systems. However, PTIO had little effect on lettuce leaves under PQ stress compared with that of PQ stress alone. The obtained data suggest that the damage caused by PQ stress is in part due to increased generation of active oxygen by maintaining increased antioxidant enzyme activities and SNP protects plants from oxidative stress. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative damage induced by PQ stress and thus confer PQ tolerance.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.348-351
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• 2007

This study was conducted to find out the change of infernal quality, such as vitamin C and nitrate contents in some leaf vegetables grown hydropoincally in different nutrient conditions. Pak-choi (Brassica camperistis L. spp. chinesis Jusl.), chungchima (Lactuca sativa L. var. crispa cv. Chungchima) and romaine (Lactuca sativa L. var. longifolia Lam.) lettuces were cultivated for 2 weeks in 4 different nutrient solutions, such as tap water; no-nutrient, added $NH_4$, discarded $NO_3$, and supplied Yamazaki' solution for lettuce as a control. The growth of leaf vegetables was not different among nutrient solution treatments except tap water. The nitrate content showed the highest in control, and followed by $+NH_4$ treatment, $-NO_3$ and tap water treatment, regardless of kind of vegetables. The vitamin C content in 3 different vegetables showed the opposite result against nitrate content so that the treatment that showing the highest vitamin C content was tap water in romaine and chungchima lettuces, and $-NO_3$ treatment in pak-choi. The vitamin C and the nitrate content showed high correlations; $r=-0.614^*$ in pak-choi, $-0.651^*$ in romaine lettuce, and $-0.804^{**}$ in chungchima lettuce.

• Korean Journal of Plant Resources
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• v.31 no.5
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• pp.538-546
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• 2018

Inflorescence, stem, and leaf samples of lettuce grown in a greenhouse in spring and autumn seasons were assayed for sesquiterpene lactones (SLs) content by high performance liquid chromatography. The concentrations of SLs were significantly higher in the inflorescences followed by upper leaf and stem compared to the other plant parts in most of the samples. SLs content (sum of lactucin and lactucopicrin) in various tissues of lettuce cultivated in spring season varied from 5.7 to 22.5 fold ranging from $27.4{\mu}g/g$ dry weight (DW) in the upper stem (cultivar "PI 176588") as the lowest to as high as $2,292.0{\mu}g/g$ DW in the inflorescence (cultivar "709849-1"). During autumn cultivation, the concentration of SLs varied from 2.0 to 14.4 fold ranging from as low of $32.4{\mu}g/g$ DW in the lower stem (cultivar "PI176588") to as high of $838.0{\mu}g/g$ DW in the upper leaf (cultivar "Dambaesangchu"). Higher lactucin (1.2 to 5.6 fold) and lactucopicrin (1.1 to 3.9 fold) concentration was observed during spring compared to autumn cultivation in most of the samples. SLs content in various organs of lettuce increases from the basal plant part going upwards. As lactucin and lactucopicrin are the major SLs which affects the sensory property of lettuce, their quantitative variation in the lettuce cultivars is useful for breeding new varieties with better consumer acceptance.

• Korean Journal of Environmental Biology
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• v.37 no.2
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• pp.144-154
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• 2019

The flora of naturalized plants in historic sites, urban parks and stream of Gyeongju-si, South Korea were summarized as 84 taxa including 21 families, 59 genera, 78 species, 1 subspecies, and 5 varieties. Direct investigation was conducted in a historic site with 68 taxa, a neighborhood park with 43 taxa, a stream with 59 taxa and a small park with 42 taxa at 86 sites. Among them, 31.0% (Naturalized Degree (ND) 3) was common but not abundant, 29.8% (ND 5) was common and an abundant plant, 20.2% (ND 2) was local and not an abundant plant. 7 taxa such as Lactuca scariola, Symphyotrichum pilosum, Rumex acetosella were invasive alien species. Lactuca scariola was the most abundant with 41.9%, Symphyotrichum pilosum was more abundant around stream with 34.9%, and Rumex acetosella was abundant on historic sites or small park with 25.6% in all the surveyed sites. To prevent spread of invasive alien species, monitoring may be required, especially, in early settlement stage. A proper management plan needs to be incorporated through physical removal of those plants, substitution of soil and so on.

• Research in Plant Disease
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• v.12 no.3
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• pp.294-297
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• 2006

Leafy lettuce(Lactuca sativa L.) is one of the most important vegetable crops in Korea, cultivated throughout the year in greenhouses. During the autumn of 2005, powdery mildew of lettuce that is a new disease caused by Podosphaera fusca occurred in several plantings grown in plastic houses near Suwon in central Korea. Further survey on commercial fields of the plant in central and southern Korea revealed its widespread occurrence and severe losses. Infections occur on upper part of mature leaves often cause leaf distortions, withering, and reduced vigor and growth. Among 184 greenhouses surveyed 121 were infested by the disease and 52 showed over 10% infection rate. Yields were greatly reduced by the disease reaching only 59% compared to healthy plants. About 60% leaves of infected plant were not marketable and fresh weight of the leaves was 73.6% compared to healthy leaves. Total yield of the greenhouses infested by the disease ranged from $100{\sim}140kg$, while it was 260 kg in a non-infested greenhouse at one time harvest. Since the disease represents a threat to safe cultivation of leafy lettuce in Korea, environmentally-friend control strategies should be urgently developed.

• Korean Journal of Plant Tissue Culture
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• v.27 no.6
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• pp.435-439
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• 2000

Explants of lettuce (Lactuca sativa L.) were cocultured with A. tumefaciens LBA 4404 harboring ${\gamma}$-tocopherol methyltransferase (${\gamma}$-TMT) gene from Arabidopsis thaliana. These explants were transferred to MS medium supplemented with 50 mg/L kanamycin, 500 mg/L carbenicillin, 0.1 mg/L NAA and 0.5 mg/L BA. After 4 weeks, kanamycin resistant shoots were obtained from the explants on the selection medium. The putative transgenic shoots were transferred to rooting MS medium supplemented with 50 mg/L kanamycin and 250 mg/L carbenicillin. Stable incorporation of the Arabidopsis ${\gamma}$-TMT cDNA into lettuce genomic DNA was confirmed by PCR and Southern analysis. HPLC analysis showed that $\alpha$- to ${\gamma}$-tocopherol ratio increased over four fold in a transgenic lettuce line indicating successful expression of the transgenic Arabidopsis ${\gamma}$-TMT in lettuce.

• Korean Journal of Plant Tissue Culture
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• v.27 no.6
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• pp.475-478
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• 2000

The cytosolic glutathione reductase(GR) gene of chinese cabbage was introduced into Lettuce (Lactuca sativa L.) with particle bombardment method. When cotyledon explants were treated with osmoticum-conditioning medium (0.6 M sorbitol/mannitol) 4 hours prior to and 16 hours after bombardment, it was identified by GUS assay that this condition was the most efficient one for introduction of foreign genes into cotyledon tissue of lettuce with particle bombardment. The stable integration of a GR gene was confirmed by the PCR analysis. 0.3, 0.6, 1.5 kbp PCR fragments of transgenes were obtained by three types of primers designed on the basis of GR sequence. To know whether the expression of the GR gene of pBKs-GR 1 can be stably maintained in the next generation, T$_2$selfing seeds obtained from the transformed mother plants were sowed on MS medium supplemented with 200 mg/L kanamycin sulfate. 70% of seedlings showed resistance to kanamycin.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.178-184
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• 2004

This study carried out to develope the vision system which automatically finds out a optimum transferring period of plants (Perilla, Platycodon grandifloums and Lactuca sativa) by using image process-ing. This system mearsured a height, long diameter and short diameter of the three plants with 20 replications. Following results were obtained on each plant. Compared with real data to be measured by hand with the vernier calipers, height, long diameter and short diameter of Perilla showed 0.5 mm average error rate with 1.7%, 4.7 mm average error rate with 3.9% and 5.5 mm average error rate with 6.9% respectively. Those of Platycodon grandifloums showed 2.4 mm with 8.1%, 3.4 mm with 7.2% and 4.0 mm with 10.4% respectively. Those of Lactuca sativa showed 4.0 mm with 9.1 %,3.4 mm with 7.2% and 3.6 mm with 9.4% respectively. The system could be used to transfer accurately the plant seedling, if the system were improved enough to reduce error rate for the optimum transferring period of a plant in the greenhouse.

• Toxicological Research
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• v.22 no.4
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• pp.333-338
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• 2006

This study was to investigate the preventive effects in anti-oxidation of Ulva lactuca extract fractions (ULEF) against $CCl_4$ toxification in liver total homogenate and mitochondrial fraction of ULEF-pretreated and carbon tetrachloride $(CCl_4)-posttreated$ rats. ULEF was intraperitoneally administered into rats at dose of 1 ml/kg for14 days. On the day 15, 3.3 ml/kg of $CCl_4$ dissolved in olive oil (1:1) was injected 12 hr before anesthetization. Activities of superoxide dismutase(SOD) in mitochondrial fraction were measured and catalase (CAT), glutathione peroxidase (GPx), malondialdehyde (MDA) in liver total homogenate. SOD, CAI and GPx were higher in the ULEF-pretreated and $CCl_4-posttreated$ group than those in the $CCl_4-posttreated$ group, and the pretreatment of ULEF decreased MDA. These results showed that the pretreatment of ULEF had the preventive role in the activities of anti-oxidative enzymes, SOD, CAT and GPx