• Asian Journal of Turfgrass Science
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• v.21 no.1
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• pp.1-7
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• 2007

This study was initiated to evaluate the qualitative characteristics of creeping bentgrass(Agrostis palustris Huds.) cultivars for the climate In Korea through the NTEP(Nat'l Turfgrass Evaluation Program) data. 'L-93' showed the highest rating in overall mean visual quality. It was also the most prominent cultivar in seedling vigors, ground cover, and genetic color especially in summer. In case of turf texture, 'Penn A-1' and 'A-2' were the finest group, but the poorest group in cold tolerance. Leaf density and thatch accumulation were lower with 'Penncross', 'Pennlinks', 'Crenshaw', and 'L-93' as compared with 'Penn A'-type and 'G'-type cultivars. Resistance to moss invasion was greater with 'Penn A'-type and 'G'-type cultivars, but 'Penncross' was the least. These observations indicated that leaf density was considered to associate with the characters of turf quality, thatch accumulation and resistance to moss invasion. 'Penn A'-type cultivars were highly resistant to snow mold. Greater resistance to brown patch was associated with 'Penn A' and 'Penncross'. Higher resistance to pythium blight was found with 'Penncross' and 'Pennlinks'. 'L-93' showed higher resistance to dollar spot, but not to pythium. Therefore, these results demonstrated that turf maintenance program for the new bentgrass cultivars should be different from a conventional management for the cultivar of 'Penncross'.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.364-372
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• 1995

On the outbreak of paralytic shellfish poisoning in April 1993 in most of shellfish harvesting areas in Jinhae Bay, Korea, to clarify the toxin production of causative organism Alexandrium species, 19 axenic clonal isolates established from the benthic resting cysts in three different stations of those culture grounds were subjected to PSP toxin analysis by HPLC. Individual toxin content per cell was highly variable among the strains isolated from a sampling area and originated from an individual cyst. Average toxin contents in those areas revealed higher values of 54-70 fmol/cell. Toxin profiles included C1/C2(epiGTX8/GTX8), GTX1/GTX4 and neoSTX as the major components, and GTX2/GTX3, GTX5, C4, dcSTX and STX as the minor or sporadic ones. neoSTX on the dominant toxins showed not only most diverse compositional changes comprising $5-54 mol\%$ ranges but also no detection on the half of the strains examined, which were implicated in arising of heterogeneity with a genetic trait within a geographical region. When average toxin composition was compared, carbamate toxins comprised large proportions of $57\%,\;54\%\;and\;67\%$ as total toxin in St. 1, St. 2 and St. 4, respectively. These results suggested that an extensive paralytic shellfish toxification in Jinhae Bay could be largely due to the production of highly potent carbamate toxins in the causative dinoflagellate Alexandrium species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.21-27
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• 2008

Germination of soybean and growth of its sprouts should be affected by storage condition and period of seeds. The experiment was conducted to examine the effects of period stored at cold room and storage conditions on their growth and morphological characters. The seeds, cv. Pungsannamulkong, were stored at $3^{\circ}C$ for 1 or 2 years, and by the three different storage methods of indoor, cold room, or transfer of indoor to cold room. Compared to the seeds stored for 2 years, one-year seeds had higher rate in hypocotyl of longer than 7 cm, root and hypocotyl lengths, and more hypocotyl fresh weight although there was not significant difference in total fresh weight. In the storage method experiment, one-year seeds stored at cold room and by transfer of indoor to cold room showed better growth, more lateral roots and fresh weights, although only two-year seeds stored at cold room did the same response, indicating that growth of soybean was affected by period and method of seed storage.

• Applied Biological Chemistry
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• v.7
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• pp.1-13
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• 1966

1) Three ${\beta}-1$, 4-mannanases were isolated from germinated guar bean through extraction, ammonium sulfate fractionation, column chromatography on cellulose derivatives and gel filltration on Sephadex G-100. They were designated as ${\beta}-1$, 4-mannanase A,B and C, respectively, in the order of isolation. 2) These enzymes were different in several aspects such as pH optimum, effect of metal ions, adsorbability on cellulose derivatives, molecular weight, Michaelis constant toward reduced ivory nut mannan A, mode of action and extent of hydrolysis of the mannan. 3) ${\beta}-1$, 4-Mannanases A and C were proposed to be two different endo-enzymes of random-splitting type producing a series of oligosaccharides from ${\beta}-1$, 4-mannans. ${\beta}-1$, 4-Mannanase B was suggested to be possibly an exe-type enzyme catalyzing a stepwise splitting from the non-reducing end of ${\beta}-1$, 4-mannans to produce mannose. 4) Guaran was subjected to hydrolysis by the purified enzymes and the consequence was discussed in connection with structural requirements of the enzymes toward substituted ${\beta}-1$, 4-mannans and their role in germinating guar seeds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.2
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• pp.112-121
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• 1988

Soybean seed coat consisted of three layers, and the aleurone layer was attached to the innermost part of seed coat. It showed the different morphological characteristics with single cell layer compared with many cell layers in barley aleurone layer. The structural difference in aleurone cell among varieties was not detected in this experiment. The hole of middle part of hilum consisted of net formed material in order to pass water and gas. In the experiment, it was not studied whether the varieties with hard seed consist of the same structure or not, but the detailed study on this would be necessary. The activity of acid phosphatase showed a tendency to increase in process of imbibition in distilled water. There was no significant difference in the enzyme activity among the varieties tested, but the enzyme activity of Danyoupkong was slightly higher than that of Hwanggeumkong. In germinability, Danyoupkong is higher than Hwangkeumkong, so it might be attributed to the higher activity. There was no difference in acid phosphatase activity between released from the aleurone cell and accumulated in the aleurone cell from 6 to 12 hours incubation of the medium in the absence of GA$_3$, but the difference was detected after 12 hours incubation. And enzyme activity was the highest in the 18 hours incubation. The increase in the release of acid phosphatase from the aleurone cell would be considered as passive diffusive effect due to the increase in turgo pressure of aleurone cell. The acid phosphatase released from aleurone layer increased greatly after 24 hours incubation of the medium in the presence of GA$_3$ and the accumulation within the aleurone cell decreased linearly after 18 hours incubation. The result indicates that GA$_3$ enhance the rate of enzyme release from aleurone layer, suggests that the aleurone cell wall be digested by the introduction of GA and the digested wall act as the channels for enzyme release.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.05a
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• pp.35-81
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• 1998

Distinct Element Method(DEM) has a great advantage to model the discontinuous behaviour of jointed rock masses such as rotation, sliding, and separation of rock blocks. Geometrical data of joints by a field monitoring is not enough to model the jointed rock mass though the results of DE analysis for the jointed rock mass is most sensitive to the distributional properties of joints. Also, it is important to use a properly joint law in evaluating the stability of a jointed rock mass because the joint is considered as the contact between blocks in DEM. In this study, a stochastic modelling technique is developed and the dilatant rock joint is numerically modelled in order to consider th geometrical and mechanical properties of joints in DE analysis. The stochastic modelling technique provides a assemblage of rock blocks by reproducing the joint distribution from insufficient joint data. Numerical Modelling of joint dilatancy in a edge-edge contact of DEM enable to consider not only mechanical properties but also various boundary conditions of joint. Preprocess Procedure for a stochastic DE model is composed of a statistical process of raw data of joints, a joint generation, and a block boundary generation. This stochastic DE model is used to analyze the effect of deviations of geometrical joint parameters on .the behaviour of jointed rock masses. This modelling method may be one tool for the consistency of DE analysis because it keeps the objectivity of the numerical model. In the joint constitutive law with a dilatancy, the normal and shear behaviour of a joint are fully coupled due to dilatation. It is easy to quantify the input Parameters used in the joint law from laboratory tests. The boundary effect on the behaviour of a joint is verified from shear tests under CNL and CNS using the numerical model of a single joint. The numerical model developed is applied to jointed rock masses to evaluate the effect of joint dilation on tunnel stability.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.390-393
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• 1997

Hormetic effects of low dose radiation were analyzed in terms of growth stimulation in radish and three cultivars of chinese cabbage. Seeds irradiated with ${\gamma}$ radiation were planted in the green house and in the experimental field. Though it varied with cultivars of tested plants, hormetic effect of low dose ${\gamma}$ radiation on an early stage of growth were shown especially in germination rates and elongation of seedlings. The height of seedlings increased in 0.2 Gy irradiated group of Seolim cultivar and radish, in 1 Gy irradiated group of Konaenggi cultivar and in 4 Gy irradiated group of Ducksung cultivar, respectively, In case of plants grown in the experimental field, prominent were the height increase of radish and Seolim cultivar in 1 Gy irradiated group and the fresh weight increase of both radish and cabbage in 4 Gy irradiated group.

• Korean Journal of Weed Science
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• v.16 no.2
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• pp.81-87
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• 1996

Seeds of rice, cv. Ilpoom, and barnyardgrasses(Echinochloa crus-galli, vars. oryzicola, crux-galli, and praticola) were sown for a characterization of their responses to temperature during emergence under a dry direct-seeded condition. A laboratory-made aluminum block apparatus for emergence-temperature control conferred a linear continuous temperature gradient from 10 to $30^{\circ}C$ to the seeds from cooling to heating ends of the apparatus. The lowest temperature for emergence was $12.3^{\circ}C$ for rice cv. Ilpoom, and $11.0^{\circ}C$ for the three varieties of Echinochloa spp.. Percent emergence of rice increased sharply with an increase in temperature by ca. $20^{\circ}C$, then leveled-off, while those of barnyardgrasses increased almost linearly with temperatures up to $30^{\circ}C$. In rice the time required for emergence after seeding was shortened exponentially with increased temperature while those for barnyardgrasses were shortened almost linearly from 11 to $30^{\circ}C$. The temperature-response characteristic of rice in emergence-speed was almost the same among those for the 1st emergence, emergence by 25, 50, 75%, or average emergence time. At $13^{\circ}C$, $346.7^{\circ}C$ days of accummulated temperature(26.67 days) were required for the 1st emergence in rice while 131.7, 136.0, and $138.7^{\circ}C$ days(10.13, 10.46, and 10.67 days) were required for the 1st emergence in E. spp., vars. crus-galli, praticola, and oryzicola, respectively. Greater cold tolerance and increasingly faster emergence of barnyardgrasses than rice below $20^{\circ}C$ seem to render the barnyardgrasses as much more competitive than rice at lower temperatures.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.183-189
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• 2000

This study was carried out to analyze ecophysiological responses for seedling of Quercus serrata, Quercus mongolica and Quercus variabilis that are the typical species of deciduous broadleaved forests in Korea. And executed experiments in the climatic control room to provide necessary information to ecological forest management and methods of natural regeneration through the analysis of seedling responses. The details of experimental analysis were growth processes of 4 months after seeding that vary with the condition of three light intensity[relative light intensity(RLI) 8%, 20%, 52%] and three soil moisture[water suction(WS) Ψ=100 hPa, Ψ=280 hPa, Ψ=330 hPa] gradient, growth factors after harvesting and the nutrition condition of leaves. The results of this study are followings: 1) Early growth was prosperous after germination for the species which have more weight of acorn. 2) The formation of lammas shoot was favourable with Q. variabilis and Q. mongolica. And the rate of the occurrence was the highest in the RLI 20%, and it was remarkably reduced in the RLI 8%. 3) As the height growth of seedling of all 3 species were greater in the RLI 20% and 8% than that of the RLI 52%, they showed strong shade tolerance. 4) The increase of light intensity promoted the diameter at root collar growth, and development of main and lateral roots with all 3 species. 5) It showed that the increase of light intensity in the experimental radiation condition raised special leaf area weight(mg/cm$^2$) and leaf area productivity(mg/cm$^2$). Consequently, these resulted in the increase of leaf thickness and total dry biomass per the unit area of leaf. 6) As the increase of light intensity, the minerals contents of leaves such as N, P and K were lowered, and the increase of soil moisture resulted in the increase of P, K, Ca and Mg.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.146-150
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• 1990

This study was conducted to investigate the genetic analysis of esterase isozymes in maize with tillers. The materials used for the study were stele tissue for five day old seedlings of IK inbred line with tiller and A-type inbred line with no tiller, their Fl and F,. The methods employed for the study were same as previous report by Lee and Choe. A total of thirteen isoesterase enzyme bands were identified and five zones were distinguised according to both migration distance and genetic segregation patterns. The E$\sub$0.3/, E$\sub$0.4/ and E$\sub$0.5/ loci appeared from orgin to 0.5cm migration distance were controlled by the two alleles in (IK/A-type)F$_2$ and the E$\sub$0.3/+E$\sub$0.4/ of variants was controlled by codominant alleles. The E$\sub$1.0/, E$\sub$1.2/, E$\sub$1.5/ and E$\sub$1.8/ loci appeared from 1.0cm to 1.8cm were also controlled by the two alleles. However, the null band was functioned alleles. The E$\sub$2.8/, E$\sub$3.0/ and E$\sub$3.5/ loci appeared from 2.8cm to 3.5cm migration distance were very active and near location. A total of individuals with two paried bands of these loci were more than those of three paired bands(x$^2$=0.327$\^$**/). The activity of bands appeared over 3.8cm were very low and these were controlled by the two alleles. In above results, genetic segregations of stele tissue of maize with tillers were suggested to be controlled by Mendelian genetic laws.