• Journal of Environmental Science International
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• v.29 no.6
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• pp.579-603
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• 2020

In order to provide fundamental information about the floristic composition of the area along with an assessment of the environmental impact, a floristic study of the vascular plants in the Tamjin River estuary in Gangjin-gun was conducted for a total of nine days, in the period from June 2014 to September 2014. We found that the vascular plants in this region comprised 424 taxa belong to 102 families, 281 genera, 390 species, 5 subspecies, 26 varieties, and 3 forma. Five taxa of Korean endemic plants including Weigela subsessilis (Nakai) L.H.Bailey, Lespedeza maximowiczii var. tricolor (Nakai) Nakai, and Clematis trichotoma Nakai were collected. Two least concern (LC) taxa of rare plants (as designated by the Korea Forest Service) were collected: Hydrocharis dubia (Blume) Backer and Platycladus orientalis (L.) Franco. Ten the floristic regional indicator taxa from the third to the fifth grade were identified: two taxa belonged to grade IV, and eight taxa belonged to grade III. Twenty-four taxa of salt-tolerant plants, including Artemisia fukudo Makino, Carex rugulosa Kuk., and Suaeda glauca (Bunge) Bunge, as well as 44 taxa of aquatic plants, including Najas marina L., Nuphar oguraensis Miki, and Nymphoides indica (L.) Kuntze, were investigated in this region. Fifty-nine taxa of naturalized plants were recorded, among which the following six taxa were plants that caused ecosystem disturbance: Ambrosia artemisiifolia L., Humulus scandens (Lour.) Merr., Lactuca scariola L., Rumex acetosella L., Solidago altissima L., and Symphyotrichum pilosum (Willd.) G.L.Nesom.

• Journal of Bio-Environment Control
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• v.14 no.1
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• pp.63-67
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• 2005

This study was conducted to investigate the effect of remained leaf number on leaf, stem and root growth of leaf lettuce (Lactuca sativa L. var. Chungchima). Plants were grown hydroponically in $0.45\pm0.15\pm3.0m$ growth channels using a recirculating DFT (Deep Flow Technique) system. The growth response to remained leaf number was evident in leaf and stem than root of leaf lettuce. Leaf fresh weight increased and leaf quality was lowered with increasing of remained leaf number. Results indicate that 4 to 6 leaves could be optimum remained leaf number of hydroponically grown leaf lettuce.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.88-92
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• 2002

The study was conducted to estimate stimulation of plant growth of blue and red leaf lettuce (Lactuca sativa L.) as affected by covering methods with vinyl materials containing concentrated PO film. Plants were grown in direct, direct and tunnel, and tunnel covering with 'Pasraido materials' from October 13 to 31. With the covering mean air temperature, soil temperature, leaf temperature and relative humidity remarkedly increased. Higher temperature was observed in the order of direct and tunnel, direct, tunnel covering and the control. Photosynthetic photon flux (PPF, $\mu$mol m$^{-2}$ . s$^{-1}$ ) was observed in reverse order of temperature. Concentration of $CO_2$ was higher during night than during day under the light. Accumulation of highest $CO_2$ at night was obtained from direct coverings followed by direct and tunnel, tunnel covering and the control. Plant height, leaf number and leaf area of blue and red lettuces were stimulated by direct covering. However, there was no significant difference.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.314-320
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• 2014

Three leaf vegetables, namely green lettuce, red lettuce (Lactuca sativa) and red-veined chicory (Cichorium intybus) were grown in minigreenhouses covered with two new functional films and conventional polyethylene film (PE). Seedlings of leaf vegetables were transplanted in a plastic troughs filled with soil-perlite mixture. Two functional films were made from polyolefin (PO) material. Measurement of optical characteristics showed that polyolefin films have better transmittance for the photosynthetic active radiation (PAR, 400-700nm) and higher absorptance for the ultraviolet radiation (UV, 300-400nm) in comparison with the conventional PE film. After three months of utilization higher loss in PAR transmittance was observed for conventional PE film. Leaf vegetables growth was enhanced and yield was increased in greenhouses covered by new functional films.

• The Journal of Natural Sciences
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• v.9 no.1
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• pp.39-44
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• 1997

This study was aimed to observe the effects of municipal sewage sludge as nutrients on the growth of Lettuce. The effects of heavy metal components of the sludge were also observed. Municipal sewage sludge from Taejon City were treated to the soil of PaiChai University Farm in order to make gradient of nitrogen concentration in soil among 6 experimental groups. Results are as follows ;The longest leaves and roots were produced in control pot, in which urea was supplied as nitrogen source to the soil. Any other sludge-treated groups produced shorter leaves and roots than control group, but the more sewage sludge treated the longer leaves and heavier vegetables were observed. No differences were observed among from 6 experimental groups in the view of N, K, Ca and Mg contents. But P contents in leaves from 6 groups varied. Zn content of Lettuce when was 65.8 mg/kg when it grew with sludge 200%. The groups treated with sludge 200% produced the vegetables of highest Zn contents. Accumulation of Zn, Mn and Cd was more heavier in Lettuce than in Altari radish. Accumulation of Zn, Mn, Cu and Cd in lettuce was not heavier than natural contents of those in market vegetables.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.217-217
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• 2017

Seed priming leading to improved emergences, germination speed and uniformity under unfavorable conditions without loss of longevity are the best level of techniques. We studied the possibility to obtain primed seed with reduced mean germination time (MGT) and uniformity but with simple, fast and effective methods. The experiments were carried out at $15^{\circ}C$ for 16 hours with priming treatment. To compare the effects of each treatment, we used 200mM $CaCl_2$ priming or hydro priming or no imbibition after ultrasonication or red light treatment. The light treatment was performed by irradiating 2000 lux of red light for 15, 30, 60, and 120 minutes. Addition, in order to investigate the effect of the priming solution, treated at 200mM $CaCl_2$ for 8 hours. Ultrasonication treatment was performed for 5, 10, and 20 minutes at exposures of 13.0, 17.3, and 21.6 kHz during priming. For liquid smoke (LS) treatment, seed soaked in 0%, 0.5%, 1.0%, 5.0% and 10.0% of diluted water and 200mM $CaCl_2$ solution. After each treatment, the seeds were dried to moisture content ranged 5-8% at $25^{\circ}C$ for 24 hours. The effect of seed treatment was evaluated with germination percentage (GP), MGT, germination index(GI), germination rate(GR), Germination Uniformity(GU) and heath seed percentage(HS). For several factors tested, we found that the desired germination improvement could be obtained by treating the seed with ultrasonication at 17.3 kHz for 5 minutes in water or red light exposure at 2000 lux for 120 min in water that resulted very similar to those used to 200mM $CaCl_2$ priming for 16 hrs. However, LS treatment showed no improvement in all diluted solution. Therefore, the methods applied ultrasonication and red light treatment showed high potential for fast and easy treatment avoiding pollution of salt solution waste.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.177-180
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• 2003

Pasteuria penetrans KW1 (PP), parasitic bacterium of nematode, was isolated from oriental melon greenhouse soil in Korea and evaluated for the suppression effect on the reproduction of southern root-knot nematode, Meloidogyne incognita (MI), in lettuce (Lactuca sativa L. var. Chungchima) and oriental melon (Cucumis melo L. var. Eunchun). Pot experiments were conducted by planting the lettuce seedlings in medium inoculated with 5,000 MI juveniles/pot (J), J +100,000 PP endospores/l g medium, and J +200,000 PP endospores/1 g medium. After 11 weeks of plantation, number of root galls in J +200,000 PP endospores/1 g medium was decreased to 92/root (38.9%, control effect), compared to the J of 150/root. In the second plantation of lettuce in the same pots, the numbers of root gall were significantly decreased in PP treated pots with 75 (77.2%, control effect) and 150/root (54.4%, control effect) in J +200,000 and J +100,000 PP endospores/1 g medium, respectively, compared to the J of 330/root when harvested at 10 weeks after planting. In oriental melon, root gall percentages were 32.1 (60.2%, control effect) and 52.9％ (34.5%, control effect) in J +200,000 and J + 1(10,000 endospores/l g medium which were significantly lower than that of 80.7％ in J.

• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.35-41
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• 1998

This experiment was conducted to find out the effect of artificial light sources(high-pressure sodium lamp, metal halide lamp and fluorescent lamp) on growth of crisphead lettuce(Lactuca sativa L.) in a plant factory. No significant differences in leaf fresh and dry weight were presented among them. Lettuce plants grown under fluorescent lamp showed the lowest growth. Considering the growth of lettuce and efficiency of lamps, it is worth using HPS(high-pressure sodium) lamp in plant factories. The leaves of lettuce plants grown under artificial light sources showed tipburn symptoms at 14th day after transplanting. The beginning of tipburn symptom have been seen on the ninth to tenth leaves from the cotyledons. It is estimated that the occurrence of tipburn was related to rapid growth and K uptake of the lettuce Plants. The Ca, Mg. Cu and Zn elements tended to be accumulated in the nutrient solutions but the T-N, P, Fe and Mn elements keep in balance in them.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.384-394
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• 1996

The experiment was conducted to determine the seed characteristics and preferable methods to enhance the seed germination rate in Bupleurum falcatum. The optimum temperature for the seed germination of Bupleurum falcatum is 2$0^{\circ}C$. Any significant promoting effects were not found in seed germination with hormone treatments and physical methods. At 15$^{\circ}C$, prechilling combined with 50~200ppm of GA$_3$ treatment raised germination rate by 2 times of control ones. The most positive effect was observed in the treatment of 10$^{-2}$ ~10$^{-3}$ M potassium nitrate only at 15$^{\circ}C$ for 12 and 24 hours. The leachate of Bupleurum falcatum didn't inhibit the germination of Lactuca sativa, showing almost 100% of germination rate, which is suggested that no inhibitors contained in the seeds of Bupleurum falcatum. Observation of embryo conditions under stereoscopic microscope showed that the ratio of seeds with or without embryo is almost 50/50. The results suggested that the lower rate of germination in Bupleurum falcatum was caused by embryolessness of seeds.

• Economic and Environmental Geology
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• v.49 no.5
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• pp.411-415
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• 2016

In this preliminary study, we assessed the toxicity of domestic bentonites using environmental toxicity testings of seed germination and bacterial bioluminescence. In cases of tested bulk bentonite samples, following ranges of toxicity were observed: -3 ~ 95% bioluminescence, 7.1 ~ 92.1% Lactuca germination. Similar results were also observed among tested other seeds, except seed Raphanus. No significant correlations between toxicity and metals contents of bentonite extractants were observed throughout this investigation. Interestingly, distinct different effects were observed according to bentonite colors (blue $67{\pm}8.7%$, pink $27{\pm}10.4%$, brown $58{\pm}14.5%$).