• The Korean Journal of Ecology
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• 제4권1_2호
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• pp.38-51
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• 1981

The present investigation was estimated the effect of temperature, precipitatiion, and time on the decomposition of litters with litter bags of Pinus densiffora and Quercus mongolica at Gure where elevation in 50m, and at Nogodan where elevation in 1300m on Mt. Jiri. As the above results, decomposition model was proposed to relation of the environmental conditions. And was investigated the production and decomposition of litters from the stands of various forest communities in Kwangneung, Mt. Jiri and Mt. Halla. The results are as follows; The models for the decay of organic carbon (C) was as follows: $C=Coe^{-Kt}$ (limiting factor;time) $C=Coe^{-K'te}$ (limiting factor;tempedrature) $C=Coe^{-KnP}$ (limiting factor:precipitation) As observed in litter bag method, the decomposition rate of litter in Pinus densiflora was slower than that of Quercus mongolica. The higher elevation, the slower decomposition rate. The decomposition of litters at Gure where elevation in 50m was equally influenced by temperature and precipitation. But at Nogodan where elevation in 1300m was much inflenced by precipitation. The decay constant of litters was larger in hardwood forest than in coniferous forest. In the same species, the more elevatiion, the less decomposition constant. The time required for the decay of 50%, 95^, 99% of the accumulated litters in the forest floor were faster in hardwood forest than in coniferous forest. In the same species, the higher elevatiion, the longer time required.

• 수산해양기술연구
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• 제53권4호
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• pp.437-445
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• 2017

Distribution and composition of the seabed litters in the exclusive economic zone of the West Sea of South Korea including 18 sea-blocks were investigated using a bottom trawl gear of the R/V Tamgtu 20 (National Institute of Fisheries Science) from 24th April 2011 to 4th May 2012. Each trawl shot was conducted for an hour in each sea-block and the total trawl shots was 18. As a result, 325.6 kg of seabed litter in total has been collected. The quantity of the seabed litter was highest at No. 202 of the sea-block, close to the Heuksan-Do. The highest occupied sea material was plastic (83.1% of entire seabed litters), the second highest material was metal combined with plastic (10.6%), and glass (2.9%), metals (2.3%), vinyl (0.6%), cloth (0.4%) and wood (0.2%) in order. The origin of seabed litters was from fishing gear (89.0% of all seabed litters). Therefore, it could be assumed that most seabed litters were derived from the fishing activity for example fishing nets and ropes.

• The Korean Journal of Ecology
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• 제10권4호
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• pp.183-193
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• 1987

An investigation was performed to draw the decy map of litters on the floors of pine and oak forests in Korea and to reveal the turnover cycles of N, P, K, Ca and Mg in litters. Isodecay constant lines of litter organic matter, which are depended upon the altitude, latitude and orientation, were drawn on the Korean map. The decay constants of organic matter of litters were higher in the broadleaf tree forests than in the needleleaf tree forests, and in the grasslands than in the forests. The amount of mineral nutrients such as N, P, K, Ca and Mg returned annually to soils is higher in the broadleaf tree forests than in the needle leaf tree forests, and highest in the Quercus mongolica forest of the forests.

• Asian-Australasian Journal of Animal Sciences
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• 제16권4호
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• pp.489-493
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• 2003

Reproductive traits of sows are determined chiefly by the genetic background of the dam herself. Whether the breed of the serviced boars also contributes is not yet clear. A total of 8,946 litters of Landrace (L) sows from 68 farms were examined. Of these, 876, 1,260, and 6,810 litters were produced from natural mating with L, Yorkshire (Y), and Duroc (D) breeds, respectively. The birth litter size (BLS), weaning litter size (WLS), live born piglets (LBP), and survival rate % (SR), of every litter were recorded. A general linear-model procedure was followed to estimate the effects of boars' breed (B), parity (P) and B${\times}$P interaction on the reproductive traits of the sows. Results show that BLS, WLS, and LBP were all significantly (p<0.001) affected by B and P. SR% was significantly influenced by B but not by P. L sows crossbred with Y or purebred with L produced litters with higher BLS, WLS, and LBP values than those bred with D. Pure L breeding yielded litters with lower SR% than did crossbreeding with D, while the difference between SR% due to LY and that due to LD crossbreeding was not significant. The interaction of B with P was significant with respect to BLS, WLS, and LBP (p<0.001), but not SR%. No significant B effect on reproductive traits was measured in sows at their first parity; but at latter parities, LL or LY produced litters with similarly high BLS, WLS and LBP, which values were all significantly greater than those of LD litters. The breed of boar evidently affected the subsequent reproductive performance of L sows and this effect may be further manipulated by the parity effect. Breed differences in semen quality and the success of fetus development with different interactions of the genetic background with the uterus function of the sow that may contribute to these effects are discussed.

• Journal of Ecology and Environment
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• 제29권5호
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• pp.469-478
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• 2006

The composition changes of litters were investigated to figure out the effects of the decomposition of Humulus japonicus on nutrient circulation and decomposition process in the riverine wetlands: Tan stream and Amsa-dong. Litterbags (mesh size 1 mm and 5 mm) were installed to monitor mass and nutrient changes of 5 types of litters: H. japanicus only, Miscanthus sacchariflarus only, Phragmites communis only, mixed litters including H. japonicus, and mixed litters without H. japonicus for 7 months. It was shown that k (decay rate) of the H. japanicus ($2.68{\sim}3.12$) was higher than that of M. sacchariflorus ($1.83{\sim}2.16$) and P. communis ($0.02{\sim}1.18$). The mass and organic remainings of the mixed litters including H. japonicus at Tan stream were $47.0{\sim}55.1%\;and\;47.0{\sim}54.9%$ and those of the litterbags without H. japanicus were $49.2{\sim}65.4%\;and\;47.1{\sim}57.5%$, respectively. This result indicated that the nutrient circulation was faster at H. japanicus community than others. Ca, Na, Mg, K, P, C, N and H contents reduced to around $40{\sim}80%$ of original. However, Na concentration increased up to $407{\sim}584%$ at 100 days and decreased to $248{\sim}498%$ at the end of the experiment. Decomposition rates were similar between 1 mm and 5mm mesh size litterbags and this implies that plant litters in studied areas decomposed mainly by microbes rather than small animals. This study revealed that the fast growth of H. japonicus was resulted from fast decomposition in part: positive feedback of nutrient cycling.

• The Korean Journal of Ecology
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• 제9권4호
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• pp.185-192
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• 1986

The production and decomposition rate of litters from the three different locations, Quercus acutissium forest at 630 m, Q. mongolica forests at 1, 005m and 1, 490 m of Mt. Dokyoo, were estimated by Olson model. The contents of N, P, K, Ca and Na in soils were measured and the relationships among them were elucidated. The amounts of litter production in Q. mangolica were the lowest, 378.96g/$m^2$ at 1, 490 m and the highest, 876.12g/$m^2$ at 1, 005 m. And the amounts of litter production in Q. acutissima at 630 m was 686.16 g/$m^2$. The decay rate of litters in Q. mongolica was the smallest, 0.123 at 1, 490 m, and the largest, 0.222 at 1, 005 m. And that in Q. acutissima was 0.169 at 630 m which was the medium rate. The production and decay rate of litters decreased with the ascending altitude. The values at 630 m were maller than those at 1, 005 m. This might be due to the fact that the tree species at 630 m was Q. acutissima was 0.169 at 630 m which was the medium rate. The production and decay rate of litters decreased with the ascending altitude. The values at 630 m was Q. acutissima which was different from Q. mongolica at 1, 005 m and 1, 490 m. The half-0life of litter decay in Q. monglica was 5, 634 years at 1, 490 m and 3.134 years at 1, 005 m. And that in Q. acutissima was 4.132 years at 630 m. The decay rates of litters were tend to be inversely proportional to the ascending altitude. The annual standing stocks of mineral and their amounts returned to the soil were proportional to the decay rate of organic matters.

• 한국발생생물학회지:발생과생식
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• 제5권2호
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• pp.107-114
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• 2001

환경호르몬(내분비계 장애물질)이 하등동물의 생식기 및 생식 기능 이상을 초래한다는 최근보고는 포유동물도 그 영향하에 있음을 암시한다. 따라서 2-bromopropane(2-BP)이 생쥐 차산자의 성별에 미치는 영향과 성 분화 과정 중에 발현되는 유전자를 조사하였다. 생쥐를 2-BP로 3주일 동안 주입한 암수를 4종류 조합으로 교배시 킨 후 태어난 새끼들의 성별을 이유시기에 결정하였다. 성관련 유전자들은 수태 후 10일에 어미 생쥐를 희생시켜 RT-PCR 방법으로 태자들에게서 발현되는 유전자를 탐지하였고, 동정된 범위의 핵산 서열을 기존의 보고된 서열과 비교 분석하였다. 이유시기까지 살아남은 한배 차산자 평균수는 암수를 모두 2-BP로 처리한 군에서만 약간 감소하였다. 차산자의 성비에서 암컷 어미가 2-BP로 처리된 군에서만 차산자 암컷이 수컷보다 많았으며, 그 이외의 군에서는 수컷이 암컷보다 많았다. 성 분화 시기에 발현되는 유전자들인 SRY 유전자는 416 염기, DAX1 유전자는 466 염기, SF1 유전자는 326 염기, AMH 유전자는 389 염기를 동정하였다. 이 유전자들은 흰쥐와는 89～90％의 상동성을, 그리고 사람과는 81～92％의 상동성을 보였다. 이 유전자들은 성이 결정되는 시기인 수태 10 일경에 모두 발현됨을 알 수 있었다. 따라서 2-BP는 생식능력에 어느 정도 영향을 미치는 것으로 사료된다. 포유동물의 성 분화에 미치는 내분비계 장애물질의 영향을 성관련 유전자들의 발현과 관련지어 연구할 수 있을 것으로 기대된다.

• 한국환경복원기술학회지
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• 제19권2호
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• pp.83-93
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• 2016

This study purposed to examine the water retention capacity of floor litter in deciduous forests. Water holding capacity(WHC) and interception storage capacity of Alnus hirsuta Turcz. ex Rupr., Quercus acutissima, Quercus mongolica litters were experimentally estimated. Physical characteristics of litters were also obtained to understand the relationships between water-retention capacity and litter characteristics. Experiments showed that WHC increases with specific volume of litter, varying 244.4% to 416.8% of its dry mass. Interception storage have estimated with rainfall simulation experiments. Maximum interception storage ($C_{max}$) and minimum interception storage ($C_{min}$) of litters were 220% and 138% of dry mass in Alnus hirsuta Turcz. ex Rupr., 218% and 137% in Quercus acutissima, and 240% and 156% in Quercus mongolica. Both $C_{max}$ and $C_{min}$ increased linearly with litter mass, and the values of $C_{min}$ in broadleaf litters have also linear relation to leaf area.

• The Korean Journal of Ecology
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• 제9권1호
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• pp.79-90
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• 1986

The production and decomposition of litters and nutrient cycling of forests were studied at the pine forests such as Pinus densiflora, Pinus koraiensis, Pinus rigida, Pinus thunbergii, Abies holophylla and Larix kaempfer. The annual litter production of the P. densiflora forest was the most on Mt. Mudeung which was 620.75g/$m^2$ and the least on Mt. Halla which was 155.00g/$m^2$. The decay rate of litters was the highest at the P. densiflora forest on Mt. Mudeung which was k=0.256 and the lowest at the P. densiflora forest on Mt. Halla and A. holophylla on Mt. Jiri which were k=0.099. The half time of decomposition of litters was shortest at the P. densiflora forest on Mt. Mudeung and the longest at the P. densiflora on Mt. Halla and A. holophylla forests on Mt. Jiri. The average decay rate of the L. kaempferi forests which was k=0.204 was the highest and that of the A. holophylla forests which was k=0.122 was the lowest. The decay rate tended to decrease against increasing the altitude. The annual production of litterr, the contents of mineral nutrients and the amounts of mineral nutrients inputted into the forest soil tended to increase in proportion to the decay rate, k.

• 한국가축번식학회지
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• 제16권3호
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• pp.261-267
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• 1992

The reproductive performance of SPF ICR mice under single paired mating were examined to get reproductive background data and to establish single paired rotational mating system. The results obtained were as follows : average litter size was 15.4$\pm$2.0 heads ; average weaning rate was 95.7$\pm$4.9% ; sex ratio(male/female) was 1.09$\pm$0.26 ; aveage delivery interval was 23.0$\pm$2.4 days. It was given the largest litter size at the age of 121~150 days and in 2nd~4th parities, but at the age of under 90 days and in 1st parity weaning rate and delivery interval were higher and shorter than those of the other ages and parities, respectively. In sex ratio, the number of male litters was slightly increased from that of female litters. The weaning rate of litters from dams which nuresed 12 litters was the highest among those of different litter sizes, and it was decreased dependent upon increment of litter size. There were no difference among 4 groups for reproductive performance, therefore the present study could have important sources for animal breeders who produce mice using the single paired rotational mating system.