• Korean Journal of Weed Science
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• v.30 no.3
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• pp.215-224
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• 2010

A greenhouse experiment was conducted to determine the effects of medium components and shade treatment on the growth, contents of total phenolics and flavonoids, and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity of Youngia sonchifolia. Substrates combined with coco peat and perlite (ratio 70:30 or 50:50, v/v) showed higher plant length, leaf area, and fresh weight than single substrate (P<0.05). Shade treatment also significantly reduced plant height, root length, leaf areas, and fresh weight (P<0.05) with increasing of the degree. Shading treatment, however, increased contents of total phenolics [mg ferulic acid equivalents $kg^{-1}$ dry wt.] and total flavonoids [mg naringin equivalents $kg^{-1}$ dry wt.] in shoot parts of Y. sonchifoli, showing 110.2 to 119.2 and 128.3 to 146.7 mg $kg^{-1}$, respectively. The antioxidant potential of the methanol extracts from the plants dose-dependently increased DPPH free radical scavenging activity, and the activity was higher in shoots (50.2 to 80.8%) than in roots (47.7 to 49.8%), and in shading treatment than in no shade.

• Journal of Life Science
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• v.26 no.12
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• pp.1446-1457
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• 2016

Wetlands exhibit intermediate characteristics of both terrestrial and aquatic ecosystems, and the biodiversity is rich in these unique biological habitats. The symbiotic relationships between plants and fungi that inhabit these wetlands play an important role in natural resource management, biodiversity, and conservation. Accordingly, the mujechi, having academic value for the study of the natural environment, was investigated in terms of genetic diversity of endophytic fungi, which inhabit the roots of wild plants. The internal transcribed spacer (ITS) region was amplified to identify fungal strains. In total, 226 strains were isolated and categorized into three phyla, seven classes, 10 orders, 22 families, and 31 genera. In plants by endophytic fungi were classified in Isachne globosa (Ig) to 19 genera, Scirpus karuisawensis (Sk) to 11 genera, Utricularia racemosa (Ur) to 19 genera, and one incertae sedis, Eriocaulon decemflorum (Ed) to 11 genera. The fungal taxa was identified the genera Acephala (19.9%), Tolypocladium (16.3%), Neopestalotiopsis (11.5%), and Perenniporia (7.1%). The fungal group isolated from Isachne globosa (Ig) grew the largest number of isolated fungal strains. After comprehensive evaluation, the endophytic fungal group from Utricularia racemosa (Ur) ranked highest in diversity analyses. From the roots of wild plant in mujechi-neup, it confirmed the distribution and diversity of endophytic fungi. This study provides the basic data to understand fungal community structure in peat wetlands.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.480-488
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• 1994

Low seedling growth rates of white clover (Trifolium repens L.) have been limited its good establishment to pastures. The experiment was done to determine the effect of removal of cotyledon and unifoliolate on the growth and morphological characters of contrasting white clover cultivars for 8 weeks after the treatment. Individual plants of cv. Regal (large leaf), Louisiana S-l (medium-large leaf), Grasslands Huia (medium-small leaf) and Aberystwyth S184 (small leaf) were grown in 10cm plastic pot containing a 2:1:1 soil:sand:peat moss mixture until the cotyledon or unifoliolate stage and then removed one (C1) or two cotyledons (C2) at cotyledon stage, and unifoliolate only (U), unifoliolate and one cotyledon (DC1) or unifoliolate and two cotyledons (DC2) at the unifoliolate stage. To measure the removal effect on biomass and morphological characters (leaf area, petiole and stolon lengths, growing tips and leaves), plants were sampled 4, 6 and 8 weeks after the treatment. Intact plants had greater biomass and morphological characters than removal-treated ones, Removal treatments at cotyledon stage, C1 and C2, were decreased more biomass and morphological characters than removal ones at unifoliolate stage while the severer cotyledon removal, the more reduction. Stolon length per plant and petiole length markedly inclined 6 weeks after the treatments although biomass and the other characters continuously did. Relatively large-leaved cultivar had more biomass, leaf area per plant and longer petiole than the other(s) but the reverse results were true in stolon length, growing tips and no. of leaves per plant. Biomass was linearly increased with increased leaf area but the earlier and severer removal, the less slope. The severer damage of cotyledon and unifoliolate had detrimental effects on the growth and aftermath establishment of white clover

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.2
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• pp.75-80
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• 1979

Ammonium desorption from 16 soils treated with $(NH_4)_2HPO_4$ solution (2000 ppm $NH_4$) was investigated by seven extractions with 0.01M $CaCl_2$. 1. There were 2 to 4 steps alternately appeared with fast and slow mode. 2. Desorption equation, log y=b-ax where y is desorption amount, b a constant indicating adsorption maximum, a retention constant, and x extraction number, was held for each step. 3. Desorption rate (100${\times}$desorption / adsorption) was 65% for the average of 15 soils, maximum 87% in Gimcheon series, minimum 32% in Samgag series. Yongho series (a peat soil) showed 156% indicating the release of large quantity of indigenous soil ammonium. 4. Desorption rate was negatively correlated with initial adsorption and in this relation the tested soils were classified into 3 groups. 5. The cumulative desorption curve was approaching almost to maximum in all tested soils with seven extractions. The final retention amount, ranged from 25% of CEC (Gimhae series) to 502% (Samgag Series). 6. Amount and rate of desorption did not have any significant relation with Langmuir adsorption maxima of ammonium, CEC and contents of clay, available phosphorus and organic matter. 7. The above results may indicate that adsorption and desorption of ammonium is closely related with iron, aluminum silicate and adsorption and desorption characteristics of accompanied anions.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.131-141
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• 2017

This study was conducted to investigate in vitro mass propagation methods suitable for each growth stage of A. aristata (G. Forst.) Tindale, from spore germination to sporophyte formation. Among spores germinated in $1/8-1{\times}MS$ medium and Knop medium, Knop medium yielded the highest germination percentage (87.1%). We cultured prothalli obtained from germinating spores for 8 weeks on media with different concentrations of sucrose and active carbon, as well as different concentrations and ratios of nitrogen, to select a suitable growth medium. A. aristata (G. Forst.) Tindale prothalli grew most actively in MS medium with 3% sucrose and 20 : 40 mM of $NH_4Cl$ and $KNO_3$ (total concentration of 60 mM). We investigated sporophyte formation according to soil type, finding that bedding soil mixed with perlite at a 2 : 1(v / v) ratio yielded the highest number of sporophytes per pot ($73.8/7.5{\times}7.5cm\;pot$). By contrast, when peat moss was used alone or mixed with other substrates, prothallus development and sporophyte formation were suppressed. Therefore, the most effective propagation method for A. aristata (G. Forst.) Tindale is to grow prothalli in MS medium and to induce sporophyte formation in a mixture of bedding soil and perlite (v / v = 2 : 1).

• Horticultural Science & Technology
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• v.18 no.6
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• pp.839-844
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• 2000

In developing of soil wetting agents using the mixture of polyoxyethylene octylphenyl ether [$C_8H_{17}O$ $(C_2H_4O)_{10}H$, POE] and polyoxyethylene+polypropyleneoxide tridecylether (1:1, w/w, CM-1), the effect of base carriers such as zeolite and vermiculite on changes of concentration of POE and on initial wetting of peat-vermiculite media were determined. The concentration of POE in the treatment of zeolite was higher than that of vermiculite. The treatments of POE+CM-1 with zeolite or vermiculite as carrier were effective in initial water retention of root media having about 510 mL of water per pot, where those of AquaGro and control had 490 mL and 400 mL of water per pot, respectively. In the evaporative water loss, the treatment of zeolite and AquaGro were faster than those of control and vermiculite. The treatment of AquaGro had faster water movement in root media than those of POE+CM-1 regardless of carriers and same trends were observed in the volume of water infiltrating into root media. Also, increasing the amount of POE+CM-1 resulted in increased water retention capacity, evaporative water loss, water movement in root media and amount of water infiltrating into root media.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.600-607
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• 1995

Orostachys japonicus, called Wasong and used as anti-tumor medicinal plant, was cultivated in plastic house. The experiment was done to clarify the effect of long-day and night-break treatment at the timing of bolting on its morphological characters, organ dry weight and flowering of florets. After grown in 15cm plastic boxes containing 2:1 soil:peat moss mixture for about 4 months, long-day of 16 hours and night-break of 2 hours around midnight were treated from Sept. 9. The plants were sampled 5 times at 2-week interval after the treatments. Long-day and night-break treatment delayed the growth of inflorescence and showed greater stem diameter on the last sampling and no. of leaves and bracts than the natural daylength. The treatments also had greater leaf and bract dry weight since 2 weeks, and the other fraction and total dry weights since 4 weeks but less floret dry weight from 4 to 6 weeks after the treatments than the natural daylength. The treatments, however, decreased no. of flowered florets and ratio of flowering plants although all the treatments showed nearly the same no. of total florets per plant until 6 weeks after the treatments, late October, which resulted in the modification of source to sink or vice versa. In the natural daylength, the florets were functioned as sink, while root, leaf and bract as source, but in the long-day and night-break treatments stem and florets were done as sink.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.435-444
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• 2006

A suite of extracellular enzyme activities involved in organic carbon decomposition were determined in three northern peatlands (a bog, a fen, and a swamp) over a 12 month period along with trace gas ($CO_2$ and $N_2O$) flux and DOC dynamics in the wetlands. The activities varied $0.008-0.066\;{\mu}mole\;g^{-1}\;min^{-1}$, $0.003-0.021\;{\mu}mole\;g^{-1}\;min^{-1}$, $0.003-0.016\;{\mu}mole\;g^{-1}\;min^{-1}$, $0.004-0.047\;{\mu}mole\;g^{-1}\;min^{-1}$, for ${\beta}-glucosidase$, cellobiohydrolase, ${\beta}-xylosidase$, and N-acetylglucosaminidase, respectively. In general, the activities were highest in the forested swamp followed by the fen and the bog. When the data from three wetlands are combined, the enzyme activities exhibited significant positive correlations with trace gas emission and available carbon. Further, the average activity of 4 enzymes explained about 20-40% of the variations of trace gas emssion and available carbon. The results indicate that enzymes related to the mineralization of organic carbon may play an important role in trace gas flux and DOC dynamics in northern peatlands.

• Korean Journal of Ecology and Environment
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• v.48 no.1
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• pp.26-31
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• 2015

This study was performed to evaluate the Ip-am wetland located in the Naejang National Park by analyzing vegetation and landscape and to suggest management plans. We carried out field survey in 2013 and analyzed aerial photos in 1976 and 2010 for landscape change. As a result, the places that were paddy fields in the past were dominated by 5 communities such as Salix koreensis Community (21.6%), Persicaria thunbergii Community (2.8%), Phragmites communis Community (1.1%), Molinia japonica Community (4.9%), Persicaria thunbergii-Molinia japonica Community (0.5%). On the other hand, the places that were upper fields in the past were occupied mostly by Rosa multiflora Community (6.8%), Humulus japonicus-Rosa multiflora Community (42.0%), Humulus japonicus Community (10.6%). In order to maintain and manage the wetland, water should be supplied continuously by making use of the six among the seven reservoirs located in the upper part through the hydrological survey should be accomplished. In addition, it was necessary to reinforce the banks for minimizing water outflow. It contributes to prevent dry peat and decrease in decomposition speed. Thus, it is hard to invade and settle of terrestrial plants and then secondary succession would be delayed.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.2
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• pp.100-116
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• 2002

There are several purpose to introduce microorganism into the Soil. The major purpose is to promote plant growth and inhibit plant pathogens. The model example is to put in nitrogen fixing symbiotic bacteria, Pythium and Rhizobium. In order to achieve the intended goal, the introduced microorganism should survive and colonize with sufficient density. The survival of introduced microorganism depend upon biotic and abiotic factors. Predation and competition are important among biotic factor. Water tension, organic carbon, inorganic nutrients(N, P), pH are important factor among abiootic factor. Soil texture and distribution of soil pore are also important in the survival and colonization of introduced microorganism. Selection by soil ecosystem for inoculant is a crucial factor for colonization. Good example are control of autochtonous microorganism and the introduction of surfactant biodegrading Pseudomonas. Sometimes, carriers such as peat and montmorillonite can be added to help colonization. Carriers can protect introduced microorganism by supplying protective microhabitat. Organic polymer is also used as a carrier to immobilize bacteria or industrial enzymes. Examples of these carrier are calcium alginate, agarose and k-carrageenan. The function of these carrier is to provide microhabitat and help colonization for introduced microorganism.