• Korean Journal of Environmental Biology
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• v.42 no.1
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• pp.62-79
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• 2024

Garlic mustard (Alliaria petiolata) is a species that has devastated the United States and Canada. It is known to play a role in destroying the ecosystem. In this study, the domestic distribution of garlic mustard was confirmed and a detailed distribution map was created for the Samcheok region, where the largest population has been established in South Korea. This study investigated the growth environment, life cycle, and population dynamics of the species in the Samcheok region. Garlic mustard was found in a total of 301 locations in Samcheok, with a total distribution area of 2,957 square meters. Annual plants germinated in mid-April, overwintered in rosette form, underwent vegetative growth from April 10 to April 24 the following year, and flowered from April 24 to May 7. Individuals producing seeds began to die off from June. Both annual and biennial individuals showed a trend of increasing and then decreasing in number around April 27 (118 days). Garlic mustard grew well under favorable light conditions in early spring. They showed less growth on leaf litter, short distance from roads, lower altitude, deciduous broad-leaved forest of middle and lower parts of the slope and forest edge. Without proper control measures in the Samcheok region, it is likely to spread more rapidly in deciduous broad-leaved forests along hiking trails in the Galyasan Mountains. In particular, it is more likely to extend to oak community where light enters the site during flowering than to pine community where there is less light in the site.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.37-47
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• 2021

This study carried out the plant sociological survey of Abies nephrolepis forest in Mt. Seorak, which is in danger of deterioration due to the accelerated climate change. We examined seventy quadrats obtained from the survey and used the TWINSPAN technique to classify communities. We then performed the DCA method for the sequence analysis and analyzed the characteristics of each community. A. nephrolepis forest of Mt. Seorak is composed of four communities (A. nephrolepis-Lonicera caerulea var. edulis community, A. nephrolepis-Acer komarovii community, A. nephrolepis-Ac. pseudosieboldianum community, and A. nephrolepis-Betula costata community). Each community showed a different distribution according to location because different microenvironments are formed depending on location such as altitude and slope direction, resulting in different species composition. Each community showed differences in environmental characteristics such as altitude, rock ratio, soil characteristics, and litter layer thickness. As a result, there were significant differences between communities in the number of species and individuals, coverage, tree size, and species diversity, as well as differences in species composition. The A. nephrolepis-L. caerulea var. edulis and A. nephrolepis-Ac. komarovii communities were located in high altitude with high rock ratios and had little development of tree layer. On the other hand, the A. nephrolepis-Ac. pseudosieboldianum and A. nephrolepis-B. costata communities were relatively in low altitude with high soil ratio and had the development of tree layer with high species diversity.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.17-28
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• 2003

A feeding trial was carried out to evaluate the effects of feeding Lactobacillus reuteri culture(LRC) on the performance, nutrients digestibility, intestinal microflora, serum metabolites, ammonia generation and litter dampness in broiler chicks. Four hundred eighty, one day old male chicks were fed into none, 0.1, 0.2 and 0.4% of LRC supplementation fer seven weeks. Basal diets excluded antibiotics contained ME 3,100, 3,100 kcal/kg, and CP 22.0, 20.0% for starter and grower, respectively. Weight gain of chicks fed LRC was significantly higher than no supplemental group in overall period(P<0.05). Feed intake was the highest in the 0.1% LRC, but not statistically different from other treatments. Feed conversion showed no significance among treatments. Viable Lactobacillus spp. number of chicks fed 0.2 and 0.4% LRC was significantly higher in cecum at seven weeks of age compared to the none(P<0.05). The tendency of anaerobes number was similar to Lactobacillus spp in ileum and cecum. Total number of E. coli and Salmonella were no difference in all treatments. In serum metabolites, feeding LRC increased triglyceride, and inorganic phosphorus, but no different total protein, albumin, total cholesterol, glucose, blood urea nitrogen and Ca. Nutrients digestibility improved significantly in 0.4% LRC compared to that of none(P<0.05). Fecal NH$_3$, gas generation was greatly decreased in the LRC supplemental groups(P<0.05). Moisture contents of bedding was also significantly decreased in LRC feeding group. It was concluded from the present study that feeding Lactobacillus reuteri culture improved the growth performance and nutrients digestibility of broiler chicks and minimize the fecal noxious gas emission.

• Toxicological Research
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• v.4 no.1
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• pp.55-84
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• 1988

This study was carried out to investigate the teratological potential of azinphos-methyl in the rat fetuses and to establish the nature of the effects on organogenesis and intrauterine development. The Sprague-Dawley female rats (180-210g) without previous litter were used in this study. Azinphos-methyl dosages of 0.094mg/kg, 0.4mg/kg, 1.5mg/kg were selected based on the acute intragastric $LD_{50}$ of 15mg/kg in the rat. Azinphos-methyl in water (Treatment Group), non-treatment control (Negative Control), water control (Sham Control), were administered by oral route and aqueous solution of acetyl salicylic acid (Positive Control) was administered by gavage at rate of 10 ml/kg of body weight from day 6 through 15. The results obtained were summarized as follows. 1. Decreased body weight of dams was observed in animals treated with aspirin and azinphos-methyl 1.5 mg/kg from day 7 through 14. (P<0.01) 2. There was an apparent decrement in the absolute liver weight in the azinphos-methyl 1.5 mg/kg treated group (P<0.05). However, the absolute and relative kidney weight in aspirin group (P<0.05, P<0.01) and the absolute and relative ovary weight in aspirin, azinphos-methyl treatment groups (P<0.01, P<0.05) were increased. 3. Decreased protein contents of dam's liver was observed in the aspirin and high dose azinphos-methyl treated group of animals (P<0.01). 4. The number of male-female ratio per dam increased in azinphos-methyl 1.5 mg/kg group but there was an apparent decrement in the body weight of fetuses in aspirin and high dose azinphos-methyl group (P<0.01, P<0.05). Total immature and resorbed fetuses were increased in aspirin group and the number of dead fetuses were also increased in azinphos-methyl 1.5mg/kg treated group of animals. (P<0.01, P<0.05). 5. In soft tissue defects, diaphragmatic hernia in diaphragm, anophthalmia, enlarged olfactory bulb, hydrocephalus, absence of third and lateral ventricle in skull, hydronephrosis in kidney, atrophy of left ventricle wall, enlarged apex in heart were observed. Especially, defects of diaphragm, heart and eye ball showed peak incidences in the high dose azinphosmethyl and aspirin group. (P<0.01). 6. Variations in the ossification patterns of skull, sternebrae, tail, forelimbs and hindlimbs showed peak incidences in the aspirin and high dose azinphos-methyl group. (P<0.01). 7. In the developmental indices of offspring, the mortality of aspirin and azinphos-methyl 1.5mg/kg treated group was higher than that of negative control. And, there was an apparent decrement in the body weight of fetuses (P<0.01) and considerable differences were obtained in pivoting, development of fur, auditory function, vision, quadrupled muscle development and testes descent in aspirin and azinphos-methyl 1.5mg/kg group. (P<0.01).

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.2
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• pp.127-134
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• 1999

This study was performed to obtain the basic data to present rational silvicultural tending plan. It makes these widely distributed pine-oak mixed stand and each of pure stand in middle province on object of this study and do comparative analysis of light condition about stand parameter and natural regeneration according to each slope(north, west and south) conditions of location in central part of South Korea. Sample plots for pine-oak mixed stand and pine and oak pure stand were established on each of southern, northern and western slopes based upon site and growth conditions of the slope. Sample plot was a circle of 0.05ha with a diameter of 25.24 m. A sample plot has between 30 and 40 tree in it. Total 23 sample plots were established; 9 pure pine stands, 8 pine-oak mixed stands. and 6 pure oak stands across lower, middle, upper parts of slopes. Relative light intensity within a stand was' measured by crown- photo(fish-eye lens; 180$^{\circ}$) system through fish-eye lens and by comparing each plot with the denuded through PAR-sensor. The crown closure ratio of pure pine stand (75%) shows much lower than that of mixed stand (90.9%) and pure oak stand (93%). The relative light intensity within a stand showed an opposite result. The crown closure of mixed stands tended to become gradually low as the slope moves from the north to the south, but the relative light Intensity within the stand tended to rise. By analyzing the relationship between the relative light intensity within a stand and stand parameter, light intensity within a stand tended to decrease as the diameter and N/ha increase. Number of oak seedlings and light intensity within a stand is in a straight-line regression relation. In particular, the number of oak seedlings was the highest in mixed stands on the southern slope. But no single pine seedling was found. The unfavorable conditions of l0cm thick litter layer and low relative light intensity in a stand (ranging between 4% and 8%) is considered to prevent pine seeds from germinating.

• Journal of Animal Science and Technology
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• v.54 no.1
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• pp.9-14
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• 2012

The purpose of this study was to estimate heritabilities and genetic correlations for reproductive and productive traits and to apply their estimates to selection strategies in a swine population. Reproductive and productive traits considered in this study were number of born alive piglet (NBA), number of weaned piglet (NW), loin eye area (LEA), days to 90 kg (D90KG), back fat thickness (BF), and lean meat content (LEAN). Data were collected from 9,886 litters on 2,447 sows for reproductive traits and 10,181 gilts and boars for productive traits from Jan. 2000 to Dec. 2008 in a swine GGP farm. The statistical model to estimate genetic parameters for considering traits was a multiple traits animal model with including animal and maternal additive effects and litter effects on reproductive traits and animal additive effects on productive traits as random as well as some of fixed effects. For estimating (co) variance components of several random effects, restricted maximum likelihood methodology was used on this assumed model. The estimated heritabilities by animal additive effects and maternal effects were 0.07 and 0.02 for NBA and 0.03 and 0.02 for NW, respectively. Genetic correlation estimate for direct genetic effects between NBA and NW was 0.14. Heritability estimates for direct genetic effects were 0.19, 0.39, 0.36, and 0.43 for LEA, D90KG, BF and LEAN, respectively. The genetic correlation of LEA with LEAN was 0.35. Productive traits were antagonistically correlated with reproductive traits. From these results it is concluded that, if selection is done for strong positive effects of reproductive traits, then this would decline productive performance.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.436-447
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• 2004

Wetland plants have evolved specialized adaptations to survive in the low-oxygen conditions associated with prolonged flooding. The development of internal gas space by means of aerenchyma is crucial for wetland plants to transport $O_2$ from the atmosphere into the roots and rhizome. The formation of tissue with high porosity depends on the species and environmental condition, which can control the depth of root penetration and the duration of root tolerance in the flooded sediments. The oxygen in the internal gas space of plants can be delivered from the atmosphere to the root and rhizome by both passive molecular diffusion and convective throughflow. The release of $O_2$ from the roots supplies oxygen demand for root respiration, microbial respiration, and chemical oxidation processes and stimulates aerobic decomposition of organic matter. Another essential mechanism of wetland plants is downward water movement across the root zone induced by water uptake. Natural and constructed wetlands sediments have low hydraulic conductivity due to the relatively fine particle sizes in the litter layer and, therefore, negligible water movement. Under such condition, the water uptake by wetland plants creates a water potential difference in the rhizosphere which acts as a driving force to draw water and dissolved solutes into the sediments. A large number of anatomical, morphological and physiological studies have been conducted to investigate the specialized adaptations of wetland plants that enable them to tolerate water saturated environment and to support their biochemical activities. Despite this, there is little knowledge regarding how the combined effects of wetland plants influence the biogeochemistry of wetland sediments. A further investigation of how the Presence of plants and their growth cycle affects the biogeochemistry of sediments will be of particular importance to understand the role of wetland in the ecological environment.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.358-364
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• 2011

To examine the possibility of natural regeneration of six Acer species in broadleaved mixed forest in Korean peninsula, samples of six Acer species' samaras were collected at several seed sources from September to October 2009 and 2010, and seed morphological characteristics and viability were studied using cutting method. Inflorescense type of Acer mandshuricum(AM), A. pseudosieboldianum(APS) and A. palmatum(AP) is corymb, that of A. pictum subsp. mono(APSM) and A. okamotoanum(AO) is flat-topped panicle, and that of A. ukurunduense(AU) is raceme. Number of seed-set per inflorescense proves the highest value 38.5 sets in AU and the lowest value 2.4 sets in APS. Diameter of the seeds proves highest value 13.5mm in AO, and the lowest value 4.7mm in APS. Angles between the wings proves the highest values $130.05^{\circ}$ in APS, and the lowest value $48.60^{\circ}$ in AU. Air dry weight of 20 seed-sets proves highest value 3,900mg, in AO, and the lowest value 404mg in AU. Viable seed ratio of AP proves 50%, and that of AU does 43.2%. Those of other four species ranges 8.6~22.2%. Considering postdispersal seed predators and disturbance of litter, viable seeds of APSM, AO, AM, and APS supplied in the natural forest in Korea might be insufficient for seedling establishment. This study showed that sound viable seed supply might be key factors of natural regeneration of major Acer species in Korea. The openings made by insect pests were observed on the seed-coat of APSM, AM, AU, and APS samara, and Bradybatus sharpi were observed in the samaras of APSM and AO. Further study on the seed insect fauna, pre- and post-dispersal seed viability, and annual variation on these factor should be needed.

• Journal of Environmental Science International
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• v.16 no.8
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• pp.941-957
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• 2007

This study monitored marine environments and ecological characteristics of phytoplankton in southern coastal waters during June to October in 2004-2006 and provided an information to how Cochlodinium blooms have occurred. A total of sampling sites was 16 (Dukyang bay, Goheung, Yeoja bay, Gamak bay, Gwangyang bay, Yeosu, and Namhae). Temperature ranged from $19^{\circ}C\;to\;29^{\circ}C$, which all of sampling in Yeoja bay was the highest temperature of $27^{\circ}C\;and\;29^{\circ}C$ during summer. On June, July, September, and October did not show a remarkable difference regardless of sampling sites. Yeoja and Gwangyang bays had 25-27 in salinity that was lower approximately 5-6 compared with other sampling sites. Chlorophyll had considerable fluctuations depending on sampling sites on July and October, in particular, Gwangyang bay was the highest value of $15{\mu}gl^{-1}$ that had five times as much as. Unlikely to temperature, salinity, and chlorophyll, transparency ranged from 2 m to 5 m regardless of sampling sites. Gwangyang bay was the highest DIN (Dissolved Inorganic Nitrogen) of $0.53mgl^{-1}$ on July and August that had ten times as much as, whereas DIP (Dissolved Inorganic Phosphorus) did not show a significant difference between sampling sites. On July, the correlation of DIN and chlorophyll was a negative that should extremely require DIN to grow phytoplankton, but was a positive liner on August. Mean cell number of phytoplankton reached to encounter a peak of 500 cells $ml^{-1}$ in July and August, which diatoms were dominant species and attained an abundance of >60% regardless of months. In August, the occurrence of dinoflagellates ranged from 20% to 30%. Skeletonema costatum, one of dominant speicies, was the highest occurrence to throughout sampling sites during 2004 to 2006. On the basis of cluster analysis for phytoplankton, they were distributed in all of sampling sites. Consequently, significant fluctuations of marine environments were shown in summer and S. costatum was regarded as the representive phytoplankton in southern coastal waters. In particular, the outbreaks of Cochlodinium polykrikoides have occurred in Dukyang bay, Gamak bay, Goheung, Yeosu, and Namhae, but Yeoja and Gwangyang bays did not occur. The distinguish characteristics of occurring sampling sites and non-occurring in Cochlodinium blooms based on this study was DIN that was enough to persistently grow and maintain them even a litter dissolved in water. This suggests that Cochlodinium red tide seems to be occur in off waters.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.95-103
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• 1999

This experiment was conducted to investigate how the lactation regulation such as restricted-lactation and early weaning during the suckling period influences on ovarian functions and change in serum levels of progesterone in primiparous rats. All the rats were raised in the individual cage from a few days before parturition through the suckling period. The normal lactation(NL) groups were controled 8 pups. The restricted-lactation(RL) and weaned(W) groups were subdivided into 5 subgroups as RL0, RL5, RL10, RL15 and RL20 as well as W0, W5, W10, W15, and W20 according to the day of onset of suckling. The number of pups were regulated from 8 to 4 on experimental strating day in RL gropus, and also perfectly weaned on the each on-set day in W groups. The results obtained were summarized as follows: 1. During the whole suckling period of 25 days the pups in RL group grew significantly(P＜005) faster than those in normal-lactation(NL) group. The pups in earlier RL group grew significantly(P＜0.05) faster than those in later RL rats, and there was no found any significant difference in body weight of pups between RL20 and NL group. The gestation period and litter size were found to be 21.53$\pm$0.04 days and 13.75$\pm$0.07, respectively. 2. The estrous cycle was not expressed in the NL group through the whole suckling period. An irregular estrous cycle was found around day 20 in RL0 group, and the regular estrous cycles were exhibited continuously from day 10 in the day 0 weaned rats. 3. In the rats of NL group the serum progesterone concentration increased from 33.16$\pm$2.64ng/$m\ell$ on day 0 to 122.5$\pm$53.68 ng/$m\ell$ on day 10, and then decreased slightly to 97.30$\pm$3.21 ng/$m\ell$ on day 20, but then decreased abruptly. However, the serum level of progesterone decreased greatly(P＜0.05) in 5 to 10 days following suckling restriction in the rats from which suckling began to be under restriction on day 0 or day 15. In the early weaning group the significant ( (P＜0.05) decrease in progesterone concentration was found similarly in 48 hours following weaning in all the rats weaned on day 0 through day 20. It was suggested that lactation stimulation is a very pivotal on the function of ovary.