• 한국토양비료학회지
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• 제46권1호
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• pp.32-39
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• 2013

The relationship between relative water contents of lettuce leaves and biochemical activities in lettuce was examined in this study to explore an adaptation response of lettuce to water stress from soils. Soil water contents and relative water contents of leaves were positively related to show $R^2$=0.8728. Hydrogen peroxide contents of leaves rapidly increased with reduction of soil water content, whereas soluble protein contents and dry matters rapidly decreased. And chlorophyll a and b contents of leaves decreased with increase in carotenoid content. Furthermore, the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR) increased dramatically, and mRNA transcript levels of APX, MDHAR and DHAR also increased. Relationship of relative water content of lettuce leaves to hydrogen peroxide, to ascorbate peroxidase activity, to dehydroascorbate reductase activity, and to monodehydroascorbate reductase activity was shown to be positively correlated. It is highly plausible from this study that these enzyme activities could be developed as an indicator of water states in soils.

• 한국환경과학회지
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• 제20권12호
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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.

• 한국토양비료학회지
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• 제43권4호
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• pp.498-505
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• 2010

AMF 접종원 처리가 원예작물의 생육에 미치는 효과를 구명하기 위하여 상추 (Lactuca sativa L.)에 파종단계와 이식단계에서 수단그라스를 기주식물로 증식한 g 당 30개의 포자와 AMF가 감염된 뿌리, 균사 및 토양이 혼합된 접종원을 처리한 후 이식 전후에 걸쳐 작물의 생장반응과 수량성을 비교 검토하였으며, AMF 포자밀도와 감염률 및 감염양상을 조사하였고, 작물의 무기양분의 흡수양태를 분석하였다. 상추의 파종단계에서 AMF 접종원을 처리한 후 생육반응을 조사한 결과, 파종 후 3주가 경과한 초기에서 AMF 접종원 처리구의 상추는 대조구보다 엽수는 9%, 엽의 생체중은 59%, 엽면적은 58% 및 엽장과 엽폭은 21-22%가 증가하였으며 엽록소함량은 2%가 향상되었다. 파종 후 9주가 경과하여서는 파종단계와 이식단계에서의 AMF 접종원 처리구는 대조구에 비해 엽수는 21%와 18%, 엽의 생체중은 51%와 41%, 근체중은 56%와 47%가 각각 증가하였으며 엽록소함량은 18%와 19%가 향상된 것으로 조사되었다. 상추 엽의 P 함량을 분석한 결과 이식단계에서 AMF 접종원 처리구가 대조구보다 217%가 증가된 P 함량을 보임으로서 P의 흡수이용이 증진되었고 상추의 생육에 영향을 미친 것으로 판단된다. 상추 근권토양의 AMF 포자밀도는 상추의 생육초기에 AMF 접종원 처리구가 대조구의 3배를 상회하는 높은 수준으로 나타났고, 9주가 경과하였을 때는 276-295%가 증가된 것으로 조사되었다. AMF 감염률 또한 대조구에 비해 크게 향상된 것으로 조사되었고 생육 후기에는 낭상체와 균사가 치밀하게 발달됨으로서 AMF 의존도가 높음을 확인하였다.

• 자연과학논문집
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• 제9권1호
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• pp.39-44
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• 1997

도시하수 슬러지를 경작지에 투입하여 상추를 재배하였을때 그 양분으로서의 효과와 식물체 내의 중금속 축적을 조사하였다. 토양에 질소함량을 기준으로 6개의 처리구로 나누어 슬러지를 투입하여 상추를 재배한 결과는 다음과 같다.질소를 요소로 주입한 대조구에서 슬러지 처리구보다 잎과 뿌리의 길이도 길고 무게도 무거웠다. 슬러지로 처리한 구에서는 슬러지의 투입량이 많아질수록 잎과 뿌리의 길이도 길었고 무게도 무거웠다. 식물체내의 N, K, Ca, Mg는 처리간 차이가 없었고 P의 양은 처리간 차이가 있었다. 상추의 Zn 함량은 슬러지 200%처리구에서 65.8 mg/kg으로 다른 처리구보다는 높았다. 상추의 Zn, Mn, Cd의 축적량은 근채인 알타리 무에 비하여 높았으며, 근채의 잎 부분, 뿌리 부분의 순으로 축적량이 낮았다. 그러나 상추의 Zn, Mn, Cu, Cd 의 축적량도 시중 채소류의 자연 함유량 이내 이었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권6호
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• pp.146-155
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• 2016

The field feasibility tests for a phytoextraction process were performed to identify the effect of citric acid as a chelate on the uranium (U) transfer into the plant for the naturally U contaminated soil in Duckpyeongri, Korea. For the feasibility tests, lettuce and Chinese cabbage were cultivated for 49 days on four testing grounds ($1m{\times}1m{\times}0.5m$ in each) in 2016. The citric acid solution was added to two testing grounds (one for lettuce and the other for Chinese cabbage) increasing the U transfer in two crop plants and their results were compared to those without the citric acid solution. When without the citric acid solution, the U concentration of plant after the cultivation was low (< $45{\mu}g/kg$ for leaves and < $450{\mu}g/kg$ for roots). However, with the addition of 50 mM citric acid solution, the U concentration of lettuce leaves and roots increased by 24 times and 1.8 times, and the U concentration of Chinese cabbage leaves and roots increased by 86.7 times and 5.4 times. The absolute accumulated U amount (${\mu}g$) in lettuce and Chinese cabbage also increased by 8.7 times and 50 times, compared to those without citric acid solution. Less than 8% of the U amount of exchangeable/carbonate phases was removed by using the lettuce and Chinese cabbage when the citric acid solution was not applied. However 52% and 66% of the U amount in exchangeable/carbonate phases were removed by the lettuce and the Chinese cabbage when the citric acid solution was added. The effect of the citric acid on the U transfer capability into the plants was quantitatively investigated by the field feasibility test, suggesting that U existing as exchangeable/carbonate phase in soil can be successfully removed by the phytoextraction process using Chinese cabbage with citric acid.

• Journal of Plant Biotechnology
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• 제7권3호
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• pp.195-202
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• 2005

The effects of constituent amino acids of glutathione (GSH), glutamate (Glu), cysteine (Cys) and glycine (Gly), on GSH synthesis in lettuce seedlings were examined in this study. The GSH concentration of the seedlings was increased to 5.1-fold and 1.6-fold the concentration of the control in the first leaves and roots, respectively, by simultaneous application of these constituent amino acids (Glu+Cys+Gly) at 100 mg/l to the culture solution for two days. In the first leaves and roots of these seedlings, the concentration of GSH was 180.4 and 14.6 nmole/gFW, and non-essential amino acids including Glu, Cys and Gly occupied 93.2% and 84.0% of the total free amino acids, respectively. Application of Cys greatly increased the concentration of GSH in the roots, and application of 50 mg/l Cys increased it to 26.1-fold the concentration in the control. The activity of GSH synthetase was higher in the leaves than in the roots, whereas the activity of ${\gamma}$-glutamylcysteine synthetase was higher in the roots than in the leaves.

• 농약과학회지
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• 제18권2호
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• pp.53-60
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• 2014

본 연구는 상추의 재배기간 중 살포한 농약이 상추 잎 아랫부분과 윗부분의 잔류분포를 알아보기 위해 수행하였다. 살균제 boscalid와 살충제 lufenuron을 살포 후 14일까지 12회(0, 1, 2, 3, 4, 5, 7, 8, 10, 12, 13, 14일) 시료를 채취하여 잔류량 변화를 조사하였다. Boscalid는 살포 후 0일(3시간)은 상추 잎 아랫부분과 윗부분의 잔류량은 각각 18.26 mg/kg, 84.97 mg/kg이었고, 14일 후에는 0.31 mg/kg, 0.37 mg/kg으로 나타났다. Lufenuron은 살포 후 0일(3시간)은 상추 잎 아랫부분과 윗부분의 잔류량은 각각 0.91 mg/kg, 5.21 mg/kg이었고, 13일 후에는 0.06 mg/kg, 0.09 mg/kg으로 나타났다. 두 약제 살포 후 12회 조사한 잔류량은 모두 상추 잎 아랫부분이 윗부분보다 낮게 나타났다. 이와 같은 잔류분포 양상은 2013년 잔류농약이 검출된 유통 상추 잎 16건에서도 boscalid 등 9종의 잔류량 분포는 동일하게 나타났다.

• 한국환경과학회지
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• 제33권5호
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• pp.305-322
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• 2024

The aim of this study was to investigate the effects of artificial light sources on the germination and seedling vigor of lettuce, aiming to identify the optimal artificial light source for producing high-quality seedlings. Lettuce cultivar of 'Tomalin' and 'Seonpunggold' exhibited the highest seed emergence in the Metal halide(MH) lamp and High-pressure sodium(HPS) lamp treatment group, while the emergence rate parameter, T50, was the fastest in the HPS lamp treatment group. Both cultivars showed good growth characteristics such as number of leaves, root length, and stem diameter under RGB-LED, and their seedling vigor was excellent as well. The plant height was smallest in the Red + Green + Blue LED treatment, but the leaves were round and thick, resulting in higher biomass and dry weight. Single light sources of Red LED and Blue LED led to reduced growth compared with that under the mixed light treatments. Chlorophyll content in lettuce varied with the type of artificial light, with both cultivars exhibiting the highest chlorophyll content in the Red + Green + Blue LED treatment. The most suitable artificial light for lettuce seedling growth was the Red + Green + Blue LED treatment.

• Plant Resources
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• 제8권2호
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• pp.103-109
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• 2005

Lettuce (Lactuca sativa L.) is known to contain water-soluble substances that improve antioxidant status due to the richness in antioxidants. Greenhouse experiment was carried out under different shading conditions during spring lettuce growing season. Shade significantly reduced shoot weight, number of leaves and chlorophyll content, while it increased shoot length of lettuce plants. The antioxidant potential of the individual fraction was in order of n-butanol > ethyl acetate > water > n-hexane fraction, although was less than that of commonly used antioxidants, BHT and ascorbic acid. Fractions from lettuce plants dose-dependently increased DPPH free radical scavenging activity, in vitro test. By means of HPLC analysis, BuOH fraction of cultivar 'Hwahyang' (57.93 mg $100g^{-1}$) had the highest amount of antioxidant chi orogenic acid. Shading treatment increased average amount of chlorogenic acid of all cultivars in BuoH, EtOAc, hexane and water fractions by 33, 120, 144, and $58\%$, respectively. These results suggest that lettuce plants had potent antioxidant activity, and their activities were differently exhibited depending on cultivar and fraction.

• Plant Resources
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• 제2권1호
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• pp.26-30
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• 1999

Nitrate in edible vegetables is converted to nitrite by nitrate reductase(NR) and/or bacteria in intestines. Nitrite and amino, in the intestine of some animals and human, bind to form nitrosamine, which is toxic and known as carcinogen. This study was carried out to examine the effect of added chlorides and their concentrations on growth, yield and nitrate content in leaf lettuce plants in hydroponics. Seeds of lettuce cv, "Samsunjokchukmyon" were planted on April 29, and seedlings were planted on June 2, and were cultured until July 5 in 1998. KCI and CaCl₂ were used as chloride source and their concentrations were 1, 2 and 4 me/L, respectively, in the lettuce standard nutrient solution for National Horticultural Research Institute(NHRI). Completely randomized design with 3 replications was used. Nitrate content and NR activity were measured 2 and 5 weeks after planting(WAP). The obtained results were summarized as the follows : Leaf weight per plant was difference from harvest dates and treatments, but total leaf weight was not significantly different among treatments. Number of leaves was higher in KCI 2 me/L, CaCl₂1 me/L and control at 2 WAP than the others, and was higher in KCI 1 me/L, and control at 3 WAP than others, and was higher in control at 5 WAP. Total number of harvested leaves was the highest in control with 14, which followed by KCI 2 me/L and CaCl₂1 me/L. Nitrate content was decreased by addition of chloride in nutrient solution. Nitrate content in the 3rd and 9th leaves was significantly decreased. NR activity was higher in control and CaCl₂ addition treatments, while KCI addition treatments reduced NR activity. However, no direct relationship with nitrate was observed. Growth characteristics such leaf length and leaf width were not significantly influenced by chloride addition.