• 원예과학기술지
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• 제19권4호
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• pp.568-573
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• 2001

본 실험은 triazole계 화합물을 백일홍 'Dream Land Rose'와 'Dream Land Scarlet'에 경엽살포 또는 토양관주처리를 하여 생육 및 개화에 미치는 영향을 조사하기 위하여 수행하였다. 경엽살포처리에서 'Dream Land Rose'의 초장은 tebuconazole, diniconazole, bitertanol에서 크게 감소하였으며 특히, tebuconazole이 가장 큰 왜화효과를 보였고 지상부 생체중도 가장 적었다. 꽃의 직경, 생체중, 건물중도 tebuconazole 고농도에서 현저하게 감소하였다. 한편, 개화소요일수는 약제처리에 의한 영향을 받지 않았다. 'Dream Land Scarlet'의 초장도 모든 처리에서 감소하였고, 특히 tebuconazole에서 현저한 감소를 보였다. 개화소요일수는 diniconazole에서 단축되었다. 토양관주처리에서 'Dream Land Rose'의 초장은 diniconazole과 myclobutanil에서 감소하였으나 diniconazole이 더 효과적이었다. 개화소요일수는 diniconazole에서 단축되었다. 'Dream Land Scarlet'의 초장은 모든 처리에서 감소하였으며, mycrobutanil $300mg{\cdot}L^{-1}$에서 극심한 억제현상을 보여서 개화가 이루어지지 못하였다. 개화소요일수는 diniconazole에서 증가하는 경향을 보였다.

• The Korean Journal of Ecology
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• 제21권1호
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• pp.47-63
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• 1998

In order to compare species-specific calcium metabolism, we collected 127 species belonging to 40 different families grown on various habitats including saline, limestone, wetland during the 1996 vegetation period, and analyzed their inorganic ion contents. Plants investigated were divided into 5 groups according to their physiological properties: 1) Chenopodiaceae, Aizoaceae, Caryophyllaceae, Portulacaceae and Phytolaccaceae of Centrospermales and Polygonaceae (Polygonales had a little water-soluble $Ca^{2+}$ but contained high contents of insoluble $Ca^{2+}$ particularly as Ca-oxalate (Chenopodiaceae type), 2) Some plant species such as Rosaceae produced oxalate in amounts insufficient to precipitate all incoming $Ca^{2+}$ and thus contained a surplus of dissolved $Ca^{2+}$ (Rosaceae type), 3) The contents of water-soluble $Ca^{2+}$ in plant species of Crassulaceae. Plantaginaceae, Asclepiadaceae, and Zygophyllaceae were equal to or greater than those of K ($K/Ca{\leq}1$; Crassulaceae type), and 4) K/Ca ratios of Compositae were significantly fluctuated depending on species and soil $Ca^{2+}$ level of their habitats (Compositae type). 5) Certain monocots (Gramineae, Cyperaceae, Juncaceae), in contrast to the dicotyledonous plant families mentioned above, showed a very distinct type of calcium metabolism, that is, the K/Ca ratios of 8~10 were maintained indifferently in the species and their habitat types (Graminae type). These results plants within the same taxon have similar physiological aspects as weel as morphological attributes. To understand calcium metabolism of certain plant species, therefore, it is desirable to approach on the basis of physiological concept (calciotroph or calciophobe) rather than the ecological one (calcicole or calcifuge).

• 한국토양비료학회지
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• 제6권1호
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• pp.67-73
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• 1973

Soil humic substances are defined as a humified part of the soil organic matters and regarded to play beneficial roles for colloid chemical properties and the fertility of the soils. This paper is referred to review the present trend of the studies on the forming processes of humic substances and on the effect on plant metabolism by some organic compounds that are directly absorbed by plants. It is generally considered that the humic substances are formed organic matters in soil or plant materials through numerous organic or biochemical processes. However, the nature of the constituting "core" and of attachment of carbohydrate, nitrogen containing compounds like protein, phenolic compounds and metals to the core are unclear though various models are suggested. It is reviewed that some organic compounds, phenclic acids, derived from humic substances are effective on plant metablism in many cases, although the mechanisms are remained to be clarified.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.245-245
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• 2017

Heavy metal pollution of agricultural soils affects land productivity and has impact on the quality of surrounding ecosystem. Soil microbial community parameters are used as reliable indices for assessing quality of agricultural lands under metal stress. This study investigated bacterial community structure of polluted and undisturbed paddy soils to elucidate soil factors that are related to alteration of bacterial communities under conditions of metal pollution. No obvious differences in the richness or diversity of bacterial communities were observed between samples from polluted and control areas. The bacterial communities of three locations were distinct from one another, and each location possessed distinctive set of bacterial phylotypes. The abundances of several phyla and genera differed significantly between study locations. Variation of bacterial community was mostly related to soil general properties at phylum level while at finer taxonomic levels concentrations of arsenic and lead were significant factors. According to results of bacterial community functional prediction, the soil bacterial communities of metal polluted locations were characterized by more abundant DNA replication and repair, translation, transcription and nucleotide metabolism pathway enzymes while amino acid and lipid metabolism as well as xenobiotic biodegradation potential was reduced.Our results suggest that the soil microbial communities had adapted to the elevated metal concentrations in the polluted soils as evidenced by changes in relative abundances of particular groups of microorganisms at different taxonomic resolution levels, and by altered functional potential of the microbial communities.

• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.248-254
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• 2016

A soil metagenome contains the genomes of all microbes included in a soil sample, including those that cannot be cultured. In this study, soil metagenome libraries were searched for microbial genes exhibiting lipolytic activity and those involved in potential lipid metabolism that could yield valuable products in microorganisms. One of the subclones derived from the original fosmid clone, pELP120, was selected for further analysis. A subclone spanning a 3.3 kb DNA fragment was found to encode for lipase/esterase and contained an additional partial open reading frame encoding a wax ester synthase (WES) motif. Consequently, both pELP120 and the full length of the gene potentially encoding WES were sequenced. To determine if the wes gene encoded a functioning WES protein that produced wax esters, gas chromatography-mass spectroscopy was conducted using ethyl acetate extract from an Escherichia coli strain that expressed the wes gene and was grown with hexadecanol. The ethyl acetate extract from this E. coli strain did indeed produce wax ester compounds of various carbon-chain lengths. DNA sequence analysis of the full-length gene revealed that the gene cluster may be derived from a member of Proteobacteria, whereas the clone does not contain any clear phylogenetic markers. These results suggest that the wes gene discovered in this study encodes a functional protein in E. coli and produces wax esters through a heterologous expression system.

• 한국작물학회지
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• 제46권2호
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• pp.145-149
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• 2001

This study was performed to evaluate the growth and nodulation characters of hypernodulating soy-bean mutant, SS2-2, and to know the growth and yield performance of the mutant in infertile soil. Soil fertility was adjusted by mixing the different ratios of soil components including clay, river sand, and horticultural bed, which resulted in fertile and infertile soil. Dry weight, nitrogen concentration, and leaf nitrate reductase of each plant were measured around V6 stage (47 days after planting) and around R3 stage (82 days after planting). There were significant effects of soil fertility and soybean genotype on the total dry weights including root, nodule, stem, leaf, and pod dry weight at V6 and R3 stages. Total dry weight of hypernodulating mutant, SS2-2, was clearly less than that of its wild type, Sinpaldalkong 2. However, nodule development on the roots of SS2-2 was much greater than that of Sinpaldalkong 2, regardless of soil fertility. Though SS2-2 was smaller in plant size than Sinpaldalkong 2, genotypic difference in total nitrogen content was not significant at both V6 and R3 stages because SS2-2 fixed more nitrogen biologically than its wild type in the root nodule. The SS2-2 mutant showed lower plant yield in both infertile and fertile soil. The SS2-2 contained more crude seed protein than Sinpaldalkong 2, and was characterized with reduced top and root growth.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권1호
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• pp.34-44
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• 2021

Acid mine drainage (AMD) resulting from pyrite oxidation in mining areas, subsequently leads to soil acidification accompanied by lowering pH and high concentration of metals and metalloids in its surrounding environment. Regarding to this, the microbial amelioration has been considered as a promising option for a more cost-effective and eco-friendlier countermeasure, compared to the use of alkaline chemicals. This study was aimed to evaluate influencing factors in microbially-mediated amelioration of acidic soil spiked by simulated AMD. For this, microcosm experiments were conducted by acid-neutralizing bacterial consortium (dominated by Klebsiella sp. and Raoultella sp.) under the various conditions of AMD spikes (0-2,500 mg SO42-/L), together with acidic mine soil (0-100 g) or sphagnum peat (0-5 g) in the 200 mL of nutrient medium. The employed bacterial consortium, capable of resisting to high level of sulfate concentration (up to 1,500 mg SO42-/L) in low pH, generated the ammonium while concomitantly reduced the sulfate, subsequently contributing to the effective soil stabilization with an evolution of soil pH up to neutral. Furthermore, it demonstrates that suitable condition has to be tuned for successful microbial metabolism to facilitate with neutralization during practical application.

• 한국토양환경학회지
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• 제4권1호
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• pp.13-23
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• 1999

본 연구에서는 기아상태에 있는 토양 미생물, Arthrobacter crystallopoietes cell의 2-hydroxypyridine대사능력의 변화 와 이 미생물의 대사능력에 대한 부식산의 영향에 대해 다루어졌다. 기질 2-HP에 대한 대수기 세포(exponential phase cell)는 적응기 세포(lag phase cell)와 비교할 때 기아상태에 있어서도 더 높은 2-HP대사능력을 보여 기아상태 3일 후 대수기 세포에서 2-HP반감기는 14시간으로 나타난 반면 적응기 세포의 경우 46.5시간으로 나타났다. 부식산은 기아상태에서 이 미생물 세포의 유도효소, 2-HP monooxygenase의 안정성을 높여주어 기아시간 2일 후 표준조건에서 기아상태에 있던 미생물의 효소활성이 처음의 1.5%로 남아 있는 반면 0.2% 부식산 용액에서 기아상태로 있던 미생물의 효소활성은 12%까지 남아 있었다. 기아시간 14일 후 까지도 부식산 용액 속에서 기아상태로 있던 이 미생물 세포의 2-HP대사능력은 표준 조건의 것에 비해 월등히 높아 2-HP반감기를 비교해 보면 표준 조건의 경우 43시간인 반면 부식산의 경우 1.25시간으로 나타났다.

• Journal of Ginseng Research
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• 제21권2호
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• pp.69-77
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• 1997

In order to explain the connection between ginseng rust spot and soil ecological conditions, the bed soils and ginseng roots were sampled at different microrelief units and the reducing substances of the bed soils and iron forms of the ginseng root epi dermises were determined. The results showed that the occurrence of the rust spot was connected with the ecological conditions of the soils and the metabolism of the plant which was caused by the excessive $Fe^{2+}$ in the soil solution. Ginseng rust spot was the enrichment of iron which was mainly composed of organic complex irons. Including active ferrous active ferric and non active ferric forms and they were transformed into each other following the change of soil moisture and temperature regimes. According to the regularity of growth and decline of reducing substances in soil and rust index of ginseng roots as well as the difference of adaptability to excessive $Fe^{2+}$ in soil among different year-old seeding, a new comprehensive measure based on the connection of ameliorating soil and improving cultivation system was recommended to prevent the occurrence of ginseng rust spot.

• 농약과학회지
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• 제18권4호
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• pp.258-268
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• 2014

OECD Test guideline 307에 따라 확립한 토양대사 시험법으로, 호기성 토양 조건에서 [$^{14}C$]butachlor의 토양대사 시험을 실시하였다. 시험토양은 국내 밭토양의 대표적인 토성인 양토였으며, 비멸균 및 멸균토양에 [$^{14}C$]butachlor ($6.83mgKg^{-1}$)을 처리하고 flow-through system에서 60일간 배양하였다. 시험기간 동안 mass balance는 비멸균 토양과 멸균토양에서 각 처리방사능 대비 91.1~95.5%, 93.0~97.7% 수준이었다. 비멸균 토양의 경우 처리 후 60일 경과 시 처리방사능의 8.4%로 감소하였으며, $DT_{50}$과 $DT_{90}$은 10.4일과 34.6일이었다. 토양 추출액 중 주요대사산물 2-chloro-2',6'-diethylacetanilide이 검출되었다. $^{14}CO_2$ 및 비추출성 토양잔류물은 3.5%와 43.5% 수준이었다. 시험기간 중 멸균 토양 내 [$^{14}C$]butachlor의 분해는 거의 일어나지 않았다. 따라서 butahclor는 호기성 토양에서 미생물에 의해 빠르게 분해되어 주요 대사산물 2-chloro-2',6'-diethylacetanilide와 $CO_2$를 생성하거나 토양에 강하게 흡착되어 비추출성 잔류물로 존재하는 것으로 판단된다. 이를 통해 OECD guideline TG 307에 확립한 호기성토양대사 시험법은 농약의 위해성 평가를 위한 토양 동태 예측 있어 국내 활용에 적합할 것으로 판단된다.