• Horticultural Science & Technology
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• v.29 no.5
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• pp.433-440
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• 2011

In head lettuce seedlings, NaCl stress was treated with hydroponic culture containing 0, 50, or with 100 mM NaCl in the seedling grown up to two leaf stages. Our focus was on the effect of NaCl on fresh and dry weights, antioxidant materials, and inorganic ion level. Fresh and dry weights of head lettuce seedlings increased with the increase in salinity while the optimal growth occured at 50 mM NaCl. The chlorophyll a (Chl a), total Chl and Chl a/b ratio increased 6 days after treatment with 100 mM NaCI. However, the Chl b content decreased. Total glutathione increased only in the root of head lettuce seedlings, whereas significant increase of total arcorbate content was observed in both shoot and root after the treatment with 100 mM NaCl. In addition, the NaCl treatment resulted in the decreased level of spermidine content, and a increased spermine content. Furthermore, $Na^+$ content in shoot and root increased significantly while $K^+$, $Ca^{2+}$, and $Mg^{2+}$ content decreased. The alteration of inorganic ion level after treatment with NaCl caused the reduction of $K^+/Na^+$, $Ca^{2+}/Na^+$, and $Mg^{2+}/Na^+$ ratio with the increase of NaCl concentration. Taken together, these findings indicate that the treatment of NaCl causes the induction of oxidative stress, and results in the alteration of metabolic mechanism in head lettuce seedlings.

• Korean Journal of Microbiology
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• v.38 no.1
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• pp.45-49
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• 2002

Bradyrhizobium japonicum is a soil bacterium with a unique ability to infect the roots of leguminous plants and establish a nitrogen-fixing symbiosis, which has been used as a microbial manure. In this study, we examined the stress response after pretreatment of cells with cold temperature. When pre-treated with cold temperature ($4^{\circ}C$) for 16 hr, B. japonicum increased the viability in subsequent stress-conditions such as alcohol, $H_2O_2$, heat, and dehydration. For cold adpatation, cultured B. japonicum was exposed to $4^{\circ}C$. Upon subsequent exposure to various conditions, the number of adapted cells pretreated by cold adaptation was 10-1000 fold higher than that of non-adaptated ones. It appeared de novo protein synthesis occurred during adaptation, because a protein synthesis inhibitor, chloramphenicol abolished the increased stress tolerance. By using a degenerate PCR primer set, a csp homolog was amplified from B. japonicum genome and sequenced. The deduced partial amino acid sequence of the putative Csp (Cold shock protein) shares a significant similarity with known Csp proteins of other bacteria.

• Korean Journal of Plant Resources
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• v.16 no.3
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• pp.257-263
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• 2003

The NDK1 is an ubiquitous enzyme that transfer phosphate groups from triphosphate nucleoside diphosphates(NDPs) in eukaryotes and prokaryotes. We isolated and characterized a cDNA encoding a nucleoside diphosphate kinase 1(CNDK 1) in Codonopsis lanceolata. The CNDK 1 is 444bp long and open reading frame of 447bp with a deduced amino acid of 148 residue. The CNDK 1 has an ATP binding site in 12­16 residue and phosphohistidine intermediate in 115 residue of amino acid sequence. Although several NDK 1 genes have been cloned in plants, but little is known about the functional significance of this enzyme during plant growth and development. The CNDK 1 shows the identities to Arabidopsis thaliana (71％), Oryza sativa(75％), Glycine max (79％), Brassica rapa (77％), Mesembryanthemum crystallinum (85 ％), Spinacia oleracea (83％), Pisum sativum (82％). The CNDK 1 of C. laceolata have a closer relationship of Glycine max and Pisum sativum at the phylogenic analysis.

• Korean Journal of Organic Agriculture
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• v.30 no.3
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• pp.393-407
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• 2022

The effect of Neobacillus sp. JC05 extract on the defense response in cucumber plants against root-knot nematode (RKN) was evaluated. As a result of drench treatment of JC05-extract in cucumber plants, formation of egg mass per plants and disease severity were significantly decreased compared to untreated control plants; the malondialdehyde contents also decreased in JC05-extract treated plants. When eggs of Meloidogyne incognita were inoculated, cucumber plants treated with JC05-extract elevated pathogenesis-related gene expression such as chitinase and lipoxygenase, these are well known as inducing resistance in plants, in addition, peroxidase among antioxidant enzymes was significantly activated. Moreover, the JC05-extract enhanced FDAse activity in soils grown cucumber plants inoculated by eggs of M. incognita. Taken together, these results suggest that the JC05-extract could involve in activation of defense-related mechanisms of cucumber plants and result in decrease of disease occurrence caused by M. incognita.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.125-132
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• 2011

Drought is a major limiting factor in turfgrass management. Turfgrass responses to water deficit depend on the amount and the rate of water loss as well as the duration of the stress condition. This review paper was designed to understand responses such as photosynthesis, canopy spectral reflectance, plant cell, root, hormone and protein alteration when turfgrass got drought stress. Furthermore, mechanisms to recover from drought conditions were reviewed in detail. However, there are still many questions regarding plant adaptation to water deficit. It is not clear that the mechanism by which plants detect water deficit and transfer that signal into adaptive responses. Turfgrass research should focus on the best management practices such as how to enhance the ability of self-defense mechanism through understanding plant responses by environmental stress.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.2
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• pp.137-144
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• 2007

To investigate the effect of large patch infection on oxidative stress induction, super-oxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were compared between pathogen-infected and healthy (control) zoysiagrass. The sampling for leaves and roots were carried out every 2 days for a period of 6 days. The SOD activity was not significantly affected by pathogen-infection until day 2, but significant increase of both leaves (+48%) and roots (+49%) were observed at day 6 compared with control. The CAT activity was remarkedly increased by +25% in leaves and +101% in roots within the first 2 days and then rapidly decreased. The POD activity in pathogen-infected leaves was significantly increased by 74% at day 6. The increase of POD activity in pathogen-infected roots was 2-fold higher than that of the control at day 6. These results indicated that large patch-infection induce oxidative stress, and that SOD-CAT-POD antioxidant system of zoysiagrass was effectively operated.

• Journal of Life Science
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• v.18 no.8
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• pp.1164-1168
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• 2008

We investigated gravitropic responses in the primary root of maize (Zea mays) seedlings which were exposed to salt stress. The maize roots salt-stressed with higher than 100 mM NaCl or KCl started to reveal enhanced gravitropic curvature after 2 hours form the gravi-stimulation. Such a promotion was not caused by sodium phosphate, but invoked by potassium phosphate, indicating the active component is $K^{+}$. Because NaCl increased gravitropic curvature, despite that $Na^{+}$ did not played any role, we evaluated the role for $Cl^{-}$ by comparing the effects of $MgCl_2$ and $MgSO_4$. The enhancement of the curvature only with $MgCl_2$ revealed that $Cl^{-}$ played a role in the gravi-response, indicating the involvement of anion channels. These results suggest that both of $K^{+}$ and $Cl^{-}$ play roles in the regulation of osmosis that is required for cell expansion in gravitropism as well as in nyctinasty and stomatal opening.

• 보건세계
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• v.53 no.9 s.601
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• pp.22-25
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• 2006

심신의 피로와 스트레스를 개운하게 풀 수 있는 요가 동작입니다. 그러나 이 동작을 하기 전에 먼저 준비해야 할 것이 있습니다. 일단 눈을 들어 최대한 먼 곳을 보세요. 창이 있다면 창 너머 먼 곳을 보아서 집중으로 인한 이마와 미간의 긴장을 풀어놓으세요. 미간의 긴장을 푼 뒤 눈을 감고 오른손을 왼쪽 어깨에 얹고 어깨 저속 뿌리 깊이 박혀있는 뻐근한 긴장의 정도를 느껴보고 마음으로부터 풀어놓습니다. 반대쪽도 똑같이 해줍니다. 미간과 어깨의 긴장이 풀어지면 쇄골과 가슴쪽의 호흡이 아래쪽으로 차분히 가라앉는 것이 느껴질 겁니다. 이렇게 기본적으로 이완, 호흡을 통해 심신이 편안한 가운데 다음 동작들을 시작합니다. 동작 중에는 욕심을 내 무리하지 말고 천천히 움직이면서 기분 좋은 적당한 자극을 잘 느끼도록 하고 동작 후에는 풀어지는 지극이 완전히 사라질 때까지 날 느끼도록 합니다. 이렇게만 해 준다면 피로와 스트레스를 정말 요가 한 동작으로 감쪽같이 날려버릴 수 있을 겁니다.

• Journal of Ginseng Research
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• v.24 no.3
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• pp.113-117
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• 2000

To analyze the correlation between the rusty root and the antiokidative activity in ginseng (Panax ginseng C.A.Meyer) roots, the levels of antioxidative activity in various tissues of healthy and rusty roots. The superoxide dismutase activity in rusty roots (126.9 units/mg protein) was approximately 3.5 times higher than that in healthy roots. The catalase activity in rusty roots was approximately 1.6 times higher than that in healthy roots, whereas the peroxidase activity showed a slight low level in msty roots. The 1.1 diphenyl-2-picryl-hydrazyl(DPPH) free radical scavenging activity in rusty roots was approximately 2.0 times higher than that in healthy roots. The total ascorbate content in healthy roots was 166~240 $\mu\textrm{g}$/g fr. wt. depending on the tissues. Interestingly, the oxidized dehydroascorbate (DHA) content occupied more than 80% in total ascorbate content. The total ascorbate content in rusty roots was a similar level with healthy roots, but the reduced ascorbate content was 3.5~7.5 times higher than that of the healthy roots. The total glutathione content of the epidermis, cortex and stele tissues in 겨sty roots was 7.3, 4.8, 1.2 times higher than the healthy tissues, respectively. The ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG) showed a similar fluctuation of total glutathione content in 겨sty roots. These results indicate that the high antioxidative activity in rusty roots may involve in overcoming the oxidative stress derived from environmental stresses.

• Research in Plant Disease
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• v.16 no.1
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• pp.81-85
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• 2010

Arabidopsis seedlings subjected to low pH stress in the range of pH 5.6-4.0 did not show significant retardations in root and shoot growths. Treatment of pH 3.5-2.5 resulted in significant reductions in root and shoot length, especially in roots. Chlorophyll contents in seedlings increased during acid treatment of pH 5.6-4.0, but decreased by stronger acid treatment of pH 4.0 and lower pHs. Total carotenoid contents showed similar trend to chlorophyll contents by increasing during pH 5.6-3.5 treatments and decreasing by pH 3.0-2.5. Anthocyanin contents increased under acid stress of pH 5.6-3.0 and showed great reduction at pH 2.5. The ratios of carotenoids/chlorophylls and anthocyanins/chlorophylls increased by acid stress treatments. That indicates plants try to adjust physiologically to acid stress and protect chlorophylls by increasing carotenoid and anthocyanin contents. However, different responses of chlorophylls and anthocyanins to acid stress indicate both pigments play different roles in protecting plant from acid stress.