• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.502-509
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• 2011

It is important to determine optimum soil covering depths for tree survival and growth because soil covering depths for establishing tree planting bases in coastal reclaimed lands are related to the costs for soil collection, transportation and land reclamation. The objectives of this study were carried out to determine optimum soil covering depths for the normal growth of planted trees in a coastal reclaimed land. The study sites were located in Asan National Industrial Complex in Pyeongtaek City, Gyeonggi-do. Four tree species (Pinus thunbergii, Chamaecyparis pisifera, Zelkova serrata, Quercus acutissima) with one hundred eighty trees of each species were planted in various depths of soil covering (no soil covering, 0.5 m, 1.5 m, 2.0 m soil covering treatments) on April 1998, and the tree growth patterns were measured on September 2000. The change of soil properties, tree mortality rate, root collar diameter and height growth were measured from each soil covering depth treatment on September 2000. Soil pH, EC, exchangeable cations ($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$), anion $Cl^-$, and base saturation increased with decreased soil covering depths. The mortality rates of tree species showed decreased with increased soil covering depths. The height growth of tree species increased with increased soil covering depths. Height growth of Pinus thunbergii was significantly different between the soil covering depth below 0.5m and other three covering depths, while the growth of other species (C. pisifera, Z. serrata, Q. acutissima) was significantly higher in soil covering depths below 1.5 m than in other soil covering depth treatments. The root collar diameter growth of all tree species showed increasing trends with increased soil covering depths. It is recommended to cover the soil depths above 1.5 m to decrease mortality and to stimulate the tree growth of C. pisifera, Z. serrata and Q. acutissima, while P. thunbergii which is a salt tolerate species could be planted in the 1.0 m soil covering depth.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.207-214
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• 1996

To examine the developmental capacity of manipulated embryos after ultrarapid refreezing and thawing, mouse embryos were biopsied at 4-cell stage, frozen twice at 4-cell and morula stages, respectively, and then transferred to rec-ipients. Single blastomeres were biopsied from 4-cell embryos by a modified aspiration method. Biopsied 4-cell embryos were equilibrated into freezing medium at room temperature for 2.5 min, loaded into 40 $\mu$I of freezing medium in 0.25 ml plastic straw and then directly immersed into liqiud nitrogen. Freezing medium for 4-cell embryos consisted of 4.0 M ethylene glycol and O.25 M sucrose in dPBS supplemented with 6 mg/lm BSA. Morulae were frozen into freezing medium containing 5.0 M glycerol instead of ethylene glycol. Thawing was conducted by agitating each straw in 3TC water for 20 sec. The c content of each straw was expelled into 0.5 ml of dilution medium, which consisted of 0.25 M sucrose and 3 mg/ml BSA in dPBS. The thawed embryos were rehydrated in dilution medium for 10 min, washed 3 times with dPBS and then cultured in M16 medium at 37$^{\circ}C$, 5% CO$_2$ in air. Blastocysts that developed from frozen or refrozne biopsied embryos were transferred to recipients on Day 3 of pseudopregnancy, respectively. In vitro and in vivo developmental rates of the biopsied and intact 4~cell embryos after freezing and thawing were 78 (10l/130) and 25% (10/40), and 91 (114/125) and 30% (12/40), respectively. Although the rates of in vitro development of biopsied and intact embryos to blastocyst stage were significantly different after freezing and thawing (P

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.6-19
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• 2009

We investigated the macrozoobenthos at major two harbors of Korea in July and August 2007 in order to check the changes in the species composition due to the invasive species and to make a species inventory at each harbor system. At the Incheon Harbor, a total of 88 species was sampled with abundance of 3,212 ind. m$^{-2}$ and biomass of 239 g m$^{-2}$. The most dominant species was Tharyx sp. belong to polychaete taxa, followed by Chaetozone setosa in the harbor area. The dominant species of outer area were Musculus senhousia and Sternaspis scutata. The diversity index ranged between 0.9$\sim$2.4, and evenness index between 0.3$\sim$0.9, and richness index between 1.8$\sim$3.9. Benthic pollution index ranged between 16$\sim$74. The highest benthic pollution index was at station 4. On the other hand the lowest value was at station 6, where a large amount of M. senhousia belong to mollusca occurred. At the Busan Harbor, a total of 89 species was sampled with density of 1,845 ind. m$^{-2}$ and biomass of 133.6 g m$^{-2}$ in August 2007. The most dominant species was Tharyx sp., followed by M. japonica and Cirratulus cirrata within harbor area. M. japonica was dominant species in the outer area. The diversity index ranged between 0.7$\sim$2.2, evenness index between 0.3$\sim$1.0, and richness index between 1.1$\sim$4.1. Benthic pollution index ranged between 31$\sim$90. The lowest benthic pollution index was found at site 2 within harbor area.