• The Plant Pathology Journal
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• v.30 no.1
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• pp.43-50
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• 2014

Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp.) and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.665-672
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• 2014

Elemental cellular stoichiometry of natural phytoplankton communities was examined in six large dam reservoirs in the Han River system. Carbon (C) and nitrogen (N) contents of the phytoplankton-dominated seston from Lake Soyang was higher than that from other lakes. Phosphorus (P) content showed slight variations among six lakes in the range of $0.04{\sim}0.18{\mu}mol$ P mg $DW^{-1}$. The phosphorus concentrations of lake water showed obvious positive relationship with P and C contents of the phytoplankton-dominated seston. In all six lakes, N:P ratios and C:P ratios in the phytoplankton-dominated seston were more than 23 and 133 respectively, indicating the phytoplankton communities in six lakes have been exposed in phosphorus limited condition. The relative abundance of diatoms showed significant negative correlation with C, N, P contents of the phytoplankton-dominated seston and that of cyanobacteria showed significant positive correlation. Elemental stoichiometry of diatoms-dominated seston showed distinctive less content than that of cyanobacteria-dominated seston. The cellular N:P ratios of diatoms- and cyanobacteria-dominated seston indicate that both main classes of phytoplankton in six lakes are in phosphorus deficiency. Elemental stoichiometry of the phytoplankton-dominated seston in this study could be used for the further ecological stoichiometric studies in six lakes.

• Journal of Plant Biotechnology
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• v.38 no.2
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• pp.130-136
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• 2011

Ions deficiency or excess remains one of the critical ground level environmental problems, affecting crop productivity. In this overview, we will discuss an increased application of proteomics technology in addressing this issue using rice (Oryza sativa L.) as a model crop plant. Proteomics analyses have revealed that rice proteome undergoes changes in the proteins composition and expression in response to several ionic stresses, including mineral nutrients (aluminum, nitrogen, and phosphorous) and heavy metals (arsenic, cadmium, and copper). Developed inventory of responsive proteins and their correlation with changes in physiological symptoms and parameters are a major step forward in: (i) better understanding the underlying mechanisms of ionic stresses-triggered responses in rice; (ii) comparative proteomics studies; and (iii) designing a novel strategy to improve crop plants.

• Journal of Bio-Environment Control
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• v.10 no.2
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• pp.101-105
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• 2001

Plant roots are affected by the root zone environment rather than substrate material itself. It is important to provide a suitable environment for the roots by amending the substrate and adjusting supply of the nutrient solution. In an expanded rice hull substrates, 1.5 L nutrient solution was supplied on each day at different frequency. In rice hull substrate, plant growth and yield were the greatest in the treatment where a 1.5L nutrient solution was supplied as 24 equal aliquots, wheres in perlite substrate plant growth and yield were the greatest in the treatment with 16 aliquots. Nitrogen deficiency symptoms caused by early decomposition of rice hulls by microorganisms was recovered by increasing solution EC from 1.7 to EC 2.0 dS.m$^{-1}$ for 25 days after planting. Plant growth and yield increased in the treatment of Ec 3.0 dS.m$^{-1}$ , but the cause for this increase is not clear.

• The Korean Journal of Ecology
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• v.7 no.2
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• pp.67-73
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• 1983

Jeju-Do is a volcanic island of which climate is very warm and humid, but Opuntia lanceolata Haw, showing CAM metabolism is growing at Wolyung-Ri, Hanrim-Eup, Jeju-Do. Annual productivity of Opuntia was 696.47g/m2/yr and 533.47g/m2/yr at two populations on the seashore respectively and 414.92g/m2/yr on the basalt wall of a village. Stem area index was 13.74, 6.93, and 9.30 at each population which are higher values than average range of leaf area index. The standing crop was the highest at the second cladode from the cladode showed little difference at most chemical properties of P, K, Ca and Na. Total nitrogen contents were the most at the youngest cladode and the lest at the oldest one. Soils were infertile of which organic contents were 1.5% and 5.0% on the seaside and the basalt wall respectively. The soil on the basalt wall contained little water whose water contents were 0.9% and at seashore population 15.12% of water contents were. Furthermore high exchangeable Na contents in soil added waer deficiency.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.105-110
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• 2011

BACKGROUND: In this study, 5 different treatments such as non-treatment, mixed expeller cake 1.0 N (standard nitrogen fertilizer), rice straw, rice straw+mixed expeller cake 0.5 N, rice straw+mixed expeller cake 1.0 N were performed over 4 cropping seasons over 2 years in order to identify the optimal application rate of mixture of rice straw and mixed expeller cake, organic source in organic cultivation of tomatoes. METHODS AND RESULTS: There was no difference in all treatments in case of 200 mg/kg in the nitrate nitrogen content in soil prior to the first cropping season test under the criteria for nitrogen nutrient based on yield of crops, cultivation without fertilizers seems possible. But in the second cropping season, no treatment and rice straw showed the reduction of yield and in the third cropping season, rice-straw+mixed expeller cake 0.5 N treatment showed the significant difference. The content of nitrate nitrogen in soil prior to cropping seasons was evaluated in 160 mg/kg and standard fertilization such as mixed expeller cake, source of nitrogen, are needed due to the deficiency of nitrogen. In terms of application of organic resources, rice straw showed the effects of improvements on physical properties of soil such as bulk density, cation exchange capacity and humus contents, but the mixed expeller cake did not show any significant differences in improvements on physical properties of soil. CONCLUSION(s): Fertilizer management in organic cultivation of tomatoes is thought to produce the reliable quantity of crops as well as keep the high quality of soils by using the optimal application rate of mixed expeller cake according to the contents of nitrate nitrogen in soil and rice straw which improves the physical properties of soil.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.3
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• pp.172-178
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• 2003

This study was conducted to assess the physiological tolerance of native tree species for successful restoration and revegetation of abandoned coal-mine spoils. Study sites were two coal-mine spoils (Sododong and Ssarijae) in Taebaek, Kangwon Province, Korea. Five individuals of Betula costata and of B. schmidtii were analyzed for malondialdehyde (MDA) and hydrogen peroxide ($H_2O$$_2$) content, nitrate reductase (NR) and superoxide dismutase (SOD) activity, and for carbohydrate concentration in the leaves. Trees in the abandoned coal-mine spoils were influenced by deficiencies expressed by MDA and $H_2O$$_2$ content in the leaves of two species being higher at the coal-mine spoils than in the surrounding forest. Low NR activity indirectly represented nitrogen deficiency in the soil of the coal-mine spoils; an unmanageable SOD activity implied that tolerant functions didn't net against a certain stress of the coal-mine spoils. Decreased glucose and increased starch concentration especially showed the inhibition of the carbohydrate metabolism by inadequate factors. Consequently, low nitrogen content in the real-mine soils might increase damage in trees as a result of inhibiting the expression of tolerance mechanisms against stress. Therefore, trees in coal-mine spoils need ample nitrogen to use as a metabolic energy source in order to prevent damage and increase tolerance against stress.

• Journal of Korean Society of Forest Science
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• v.88 no.3
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• pp.335-341
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• 1999

To investigate the effect of sulfate deposition un forest tree nutrition, 15 forest stands of Pinus thunbergii were selected throughout Yochon industrial complex, in which is influenced by chronic air pollution. Concentrations of sulfate sulfur, nitrogen, phosphorus, potassium, calcium, and magnesium were analysed fur current and 1-year-old needles of Pinus thunbergii tree. The results obtained were as follows ; 1. Significant higher accumulation of sulfate S, computed with that of unpolluted needles, was observed at all sites, ranging front 0.11% to 0.35% in current needles, and from 0.13% to 0.32% in 1-year-old needles. 2. Ranging from 0.60% to 1.42% in current needles, and from 0.58% to 0.88% 1-year-old needles, respectively, nitrogen concentrations were significantly lower at 7 sites for current needles, and at all sites for 1-year-old needles than at unpolluted site. 3. Phosphorus and potassium levels were significantly lower at very few sites, compared with unpolluted site. 4. Calcium concentrations were significantly lower at 8 sites and 9 sites for current and 1-year old needles than at unpolluted site, ranging from 0.123% to 0.352% and from 0.201% to 0.371% in 1-year old needles, respectively. 5. Ranking from 0.077% to 0.152% in current needles, and from 0.056% to 0.105% in 1-year-old needles, magnesium concentrations were lower at only 2 sites for current needles tut at 12 sites for 1-year-old needles. 6. There were significant declines of concentrations of calcium and magnesium in current needles as sulfate accumulation increased. For 1-year-old needles, there were significant negative correlations-hips between sulfate and nitrogen, potassium, calcium, and magnesium concentration. It is concluded that deposition of sulfuric air pollutant deteriorated nutrients status, resulting in tree decline, in Pinus thunbergii forest in Yochon industrial complex.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.751-758
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• 2006

To investigate soil management practices for increasing tree growth in arid regions of China, Xinjiang poplar (Populus alba var. pyramidalis) seedlings were planted in a nursery and windbreak and were treated with fertilizers (nitrogen and phosphorus) and absorbents (artificial; K-SAM and natural: Yuho (Artemisia ordosica)) at Dengkou in Inner Mongolia. Seedling height, diameter at breast height (DBH), biomass, and nitrogen (N) and phosphorus (P) concentrations were measured 1.5 years after the treatments. Soil texture was sandy loam for nursery and clay loam for windbreak, soil pH was 8.78 for nursery and 8.51 for windbreak, and total soil N concentration was 0.06% for nursey and 0.08% for windbreak. [n general, seedling height and DBH increased in the N fertilizer treatment compared to control or other treatments both in nursery and windbreak. Also seedling growth increased after the treatments of artificial and natural absorbents in windbreak. Total above- and belowground biomass increased after the N + P treatment. Foliage N and P concentrations following N and/or P treatments were same in the nursey, however, they significantly increased in the windbreak indicating N deficiency. It appeared that N was a limiting factor for early growth of Xinjiang poplar seedlings and artificial and natural absorbents (K-SAM and Yuho) would be useful to increase seedling growth in the arid region.

• Applied Biological Chemistry
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• v.8
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• pp.51-59
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• 1967

A split plot was laid out in 1965 for perennial application of straw by 500kg per 10 are, as main plot, and of chemical fertilizer in conventional way, as sub-plots. The sub-plot included the following 5 fertilizer treatments as (1) non-fertilized, (2) nitrogen-free, (3) phosphate-free (4) potassium-free, (5) completely fertilizer applied plots. Trends in the growth and yield of rice was observed at present experimental site in the first year, 1965, and second year, 1966, as follows: 1. Each treatmental plot showed nearly identical trends between the first and second year, in term of growth, yield and yield components. 2. Straw application deterred the initial growth at non-fertilized and nitrogen-free plots. But straw application raised the effective stem ratio and enlarged the values in yield components, finally to be resulted in the second year with significant difference. 3. Both phosphate and potassium did not much affected to plants for longer stem and larger number of tillers. 4. Effect of nitrogen, phosphate and potassium was recorded as investigated by previous research works. Phospate deficiency decreased maturing rate to a great extent. 5. Numerical index was calculated for the comparison of plots in yield, where the non-straw, completely fertilizer applied plot stands for 100. The indexes of the first and second year were as follows : at non-straw plot(indexes in the blank are from the first year trial); non-fertilized : 80.2(80.9), nitrogen-free: 83.6(89.4), phosphate-free : 89.4(93.1) and potassium-free plot: 93.5(102.4) at non-straw plot. On the other hand, indexes at straw applied plots were non-fertilized : 84.0(86.6), nitrogen-free 82.6(93.9), phosphate-free : 91.7(96.3), potassium-free: 103.2(102.0) and complete plot: 98.7(109.8).