• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.5 no.1
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• pp.10-20
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• 2024

The study investigated species diversity, relative abundance, and decline of flying insects and plants within a fragmented forest in the Federal University of Technology Akure (FUTA), Ondo State, Nigeria. It is known that habitat fragmentation can reduce biodiversity. Thus, it is important to perform comprehensive assessments to understand implications of the habitat fragmentation for flora and fauna. Species richness and abundance of flying insects and plants across fragmented forest patches were quantified using field surveys and taxonomic identification. This study revealed shifts in species diversity, with fragmented areas exhibiting reduced biodiversity compared to contiguous forest ecosystems. Flying insects crucial for ecosystem functioning and pollination services demonstrated decreased species richness and relative abundance within fragmented habitats. This decline was attributed to habitat loss, altered microclimates, and limited movement pathways known to hinder insect dispersal. Similarly, plant species richness and abundance showed decline in fragmented forest due to disrupted mutualistic interactions with pollinators, altered nutrient cycling, and increased competition among plant species. This study underscores the importance of maintaining intact forest habitats to sustain healthy ecosystems and preserve biodiversity. Effective conservation strategies should focus on habitat connectivity, reforestation efforts, and protection of essential ecological corridors to mitigate effects of fragmentation. In conclusion, this investigation provides empirical evidence for effects of habitat fragmentation on flying insects and plants in a forest ecosystem in FUTA Akure, Nigeria. Findings emphasize an urgency of adopting conservation measures to safeguard these invaluable components of biodiversity and ecosystem stability in the face of ongoing habitat loss and fragmentation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.3
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• pp.199-212
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• 2007

If a type IP-2 transport package were to be subjected to a free drop test and a penetration test under the normal conditions of transport, it should prevent a loss or dispersal of the radioactive contents and a more than 20% increase in the maximum radiation level at any external surface of the package. In this paper, we suggested the analytic method to evaluate the structural safety of a type IP-2 transport package using a thick steel plate for a structure part and a bolt for tying a bolt. Using an analysis a loss or dispersal of the radioactive contents and a loss of shielding integrity were confirmed for two kinds of type IP-2 transport packages to transport radioactive waste drums from a waste facility to a temporary storage site in a nuclear power plant. Under the free drop condition the maximum average stress at the bolts and the maximum opening displacement of a lid were compared with the tensile stress of a bolt and the steps in a lid, which were made to avoid a streaming radiation in the shielding path, to evaluate a loss or dispersal of radioactive waste contents. Also a loss of shielding integrity was evaluated using the maximum decrease in a shielding thickness. To verify the impact dynamic analysis for free drop test condition and evaluate experimentally the safety of two kinds of type IP-2 transport packages, free drop tests were conducted with various drop directions. For the tests we examined the failure of bolts and the deformation of flange to evaluate a loss or dispersal of radioactive material and measured the shielding thickness using a ultrasonic thickness gauge to assess a loss of shielding integrity. The strains and accelerations acquired from tests were compared with those by analyses to verify the impact dynamic analysis. The analytic results were larger than the those of test so that the analysis showed the conservative results. Finally, we evaluated the safety of the type IP-2 transport package under the stacking test condition using a finite element analysis. Under the stacking test condition, the maximum Tresca stress of the shielding material was 1/3 of the yielding stress. Two kinds of a type IP-2 transport package were safe for the free drop test condition and the stacking test condition.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.457-462
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• 2019

This study was conducted to investigate seed dormancy type and germination characteristics of Lonicera chrysantha. In imbibition test, the seeds imbibed water readily. Therefore, the seeds did not have physical dormancy (PY). The seeds have undeveloped embryo at seed dispersal and, then the E:S ratio (embryo/seed ratio) increased more than about 46% just before germination. In temperature experiments (5, 15, 20 and $25^{\circ}C$), the seeds did not germinate during incubation at $5^{\circ}C$. At $20^{\circ}C$, the seeds started to germinate from a week after sowing and the final germination was 86.7% at 2 weeks after sowing. At $15^{\circ}C$, the seeds started to germinate at 2 weeks and the final germination rate was 75.0% at 4 weeks after sowing. At $25^{\circ}C$, the seeds started to germinate at a week and the final germination rate was 48.3% at 19 weeks after sowing. Consequently, Optimum temperature of germination is $20^{\circ}C$ that shown highest final germination rate and shortest mean germination time. The seeds germinated all temperature treatments within 4 weeks except to $5^{\circ}C$. Therefore, it is concluded that seeds of L. chrysantha have only morphological dormancy (MD).

• Korean Journal of Environment and Ecology
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• v.35 no.4
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• pp.347-376
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• 2021

Investigating and evaluating regionally distributed plant resources provide fundamental information (inventory) to conserve plant diversity in target areas. Nevertheless, the examination of inventory to collect information in areas with little interest has been insufficient. In this study, the vicinity of Mt. Baegamsan(1,004m) was investigated for plant resources in the central and southern part of the Korean peninsula, which has received low interest. Nine surveys identified a total of 638 taxa consisting of 108 families, 339 genera, 572 species, 12 subspecies, 49 varieties, and 5 forms. One taxon was designated to be the endangered wild plant by the Ministry of Environment, and a total of 29 taxa were designated to be endemic species in Korea. Floristic target species identified by the surveys included 1 taxon for grade V, 13 taxa for grade IV, 36 taxa for grade III, 29s taxa for grade II, and 34 taxa for grade I. A total of 38 taxa were identified to be naturalized plants, and 3 of them were designated as invasive alien plants by the Ministry of Environment. There was a difference in plant distribution between western and eastern areas of Mt. Baegamsan. The endangered and valuable plants for conservation were mainly identified from Mt. Baegamsan peak area, the ridge, and the western area. Considering the plant distribution, the Mt. Baegamsan region, located on Nakdong-jungmaek, was estimated to be dispersal routes for plant expansion and retreat.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1040-1046
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• 2010

This research is composed of a series of survey of existing plants species by classifying biotope type of agro-ecosystem of Guksoo village area of Yangpyeong County, to collect and analyze basic data of vegetation analysis for indicators development of agro-ecosystem habitat quality. From the observation area, we found total 141 kinds of tracheophytes (53 Family 114 Genus 124 Species 16 Variety 1 Breed) and they are 3.36% of total Korean tracheophytes (4,191 kinds). Among those 141 tracheophytes, there are 23 kinds of naturalized plants (11 Family 20 Genus 20 Species 2 Variety) and they are 8.61% of total Korean naturalized plants (267 kinds). Among those 141 tracheophytes, they include 0.71% of pteridophyte, 0.71% of gymnosperm, 98.58% of angiosperm. So, most of them are angiosperm. When we classify them according to plant life form characteristics, dormant/diapause type plants include 45 species (31.91%) of annual plant (Th), 19 species (13.48%) of Th (w), 17species (12.06%) of hemicryptophyte (H). Regarding propagation type, as for the Radicoid form, there are 99 species (70.21%) of crumb structure plant, 13 species (9.22%) of $R_4$, 12 species (8.51%) of $R_{2.3}$ are the crumb structure does not make any connection on the ground or under ground. As for the Disseminule form of propagation type, there are 62 species (43.97%) of Gravity dispersal type $D_4$), 23 species (16.31%) of Wind dispersal type ($D_1$), 21 species (14.89%) of $D_{1.4}$. According to this survey of plant distribution rate by plant life form characteristics, we may acquire many knowledge about species composition of sociability, cluster's reaction against environmental elements, space usage and possible species competition in community. It may be very useful basic data for habitat preservation to keep and promote biological diversity.

• Animal cells and systems
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• v.5 no.4
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• pp.309-312
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• 2001

Allozyme studies have been widely used to estimate genetic variation and to describe genetic structure in natural populations. In many cases, the genetic diversity of recently established populations is generally lower than that of central populations. In addition, the genetic composition of an invasive species is influenced by its History of introduction as well as its ecological characters. Ageratina altissima (L.) R. King & H. Robinson (white snakeroot) is a perennial herb native to the eastern United States and Canada, and is currently receiving much attention for its rapid invasion of the Korean forests. Starch gel electrophoresis was used to assess the genetic variability at 11 putative loci in seven introduced populations of A. altissima in Seoul. Populations of A. altissima maintained lower levels of allozyme diversity (expected heterozygosity = 0.063) than those reported for other taxa with similar ecological traits. The degree of differentiation observed among A. altissima populations was considerably low. It is suggested that the populations were recently established from only a few founders via dispersal by human activities, resulting in the loss of genetic variation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48
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• pp.41-48
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• 2003

The number of natural products obtained from plants has now reached over 100,000 and new chemical compounds are being discovered ever year. Medicinal and Aromatic plants and their extracts have been used for centuries to relieve pain, aid healing, kill bacteria and insects are important as the antifungal and anti-herbivore agents with further compounds being involved in the symbiotic associations. Although their functions in plants have not been fully established, it is Known that some substances have growth regulatory properties while others are involved in pollination and seed dispersal. The complex nature of these chemicals are usually produced in various types of secretory structures which is an important character of a plant family and also influenced and controlled by genetic and ecological factors. Detailed anatomical description of these structures ave relevant to the market value of the plants, the verification of authenticity of a given species and for the detection of substitution or adulteration. Volatile oils are used for their therapeutic action for flavoring of lemon, in perfumery of rose or as starting materials for the synthesis of other compounds of turpentine. For therapeutic purposes they are administered as inhalations of eucalyptus oil, peppermint oil, as gargles and mouthwashes of thymol and transdermally many essential oils including those of lavender, etc. With these current trend for using volatile components in essential oil will be increasing in the future in Korea and in the world as well.

• Mycobiology
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• v.38 no.4
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• pp.229-237
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• 2010

Members of the genus Aspergillus are the most common fungi and all reproduce asexually by forming long chains of conidiospores (or conidia). The impact of various Aspergillus species on humans ranges from beneficial to harmful. For example, several species including Aspergillus oryzae and Aspergillus niger are used in industry for enzyme production and food processing. In contrast, Aspergillus flavus produce the most potent naturally present carcinogen aflatoxins, which contaminate various plant- and animal-based foods. Importantly, the opportunistic human pathogen Aspergillus fumigatus has become the most prevalent airborne fungal pathogen in developed countries, causing invasive aspergillosis in immunocompromised patients with a high mortality rate. A. fumigatus produces a massive number of small hydrophobic conidia as the primarymeans of dispersal, survival, genome-protection, and infecting hosts. Large-scale genome-wide expression studies can now be conducted due to completion of A. fumigatus genome sequencing. However, genomics becomes more powerful and informative when combined with genetics. We have been investigating the mechanisms underlying the regulation of asexual development (conidiation) and gliotoxin biosynthesis in A. fumigatus, primarily focusing on a characterization of key developmental regulators identified in the model fungus Aspergillus nidulans. In this review, I will summarize our current understanding of how conidiation in two aspergilli is regulated.

• Journal of Ecology and Environment
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• v.34 no.3
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• pp.295-305
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• 2011

Many studies have suggested the positive effects of grazing by large herbivorous mammals on seed dispersal, but little is known about how herbivores could affect the fate of ingested seeds. This study examined the effects of seed ingestion by sika deer (Cervus nippon) on seed fate in a temperate grassland established in an urban park long resided by high densities of sika deer. I compared species composition and seasonal traits of seed abundance and maturity in the grassland community with those in deer fecal pellets. In total, 27 herbaceous species were observed, including the predominant Zoysia japonica. Seed phenology and production differed among the three dominant species (Z. japonica, Digitaria violascens, and Hydrocotyle maritima). Pellets contained at least 26 species of herbaceous seeds, and their abundance differed among species. Of the 26 species, 15 were observed in the vegetation at the study site. The peak of seed abundance in pellets for the dominant species appeared 1 month after the peak of inflorescence production (but most of the inflorescences were immature and susceptible to digestion) and consequently corresponded to the peak of mature inflorescence. Because sika deer are likely to ingest seeds at any maturity stage in the grassland and immature seeds are less hardened, ingested immature seeds can suffer great losses. The results suggested that the survival of germable seeds with great losses of immature seeds may be a factor determining which plant species can be successfully dispersed by herbivores.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.254-262
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• 2019

Background: To exploit the ornamental and medicinal purposes of Lonicera harae Makino, L. subsessilis Rehder, L. praeflorens Batalin, and L. insularis Nakai, native to Korea, it is necessary to understand their seed ecology for propagation. In this study, we investigated the seed dormancy type and germination characteristics of seeds of the four Korean native Lonicera species. Results: The seeds of the four Lonicera species imbibed water readily, suggesting that the species do not have physical dormancy. Furthermore, the seeds exhibited underdeveloped embryos with only about 15-25% of the length of the seeds at dispersal. The embryos grew to the critical length with approximately 50-80% of the length of the seeds' development before radicle protrusion. Further, 94.4% and 61.1% of freshly matured seeds of L. insularis and L. harae germinated within 4 weeks after sowing at 15 ℃ and 20 ℃, respectively. Contrarily, L. praeflorens and L. subsessilis seeds did not germinate within 4 weeks under all temperature treatments. At 15 ℃, L. praeflorens seeds started to germinate from 5 weeks and the final germination rate was 51.1% at 13 weeks. At 15 ℃, L. subsessilis seeds started to germinate from 5 weeks after sowing and the final germination rate was 85.6% at 17 weeks after sowing. Embryo growth and germination of L. praeflorens and L. subsessilis occurred at a relatively high temperature (≥ 15 ℃). Conclusions: Overall, L. insularis seeds have only morphological dormancy. The seeds of L. harae have approximately 60% and 40% of morphological dormancy and morphophysiological dormancy, respectively. Contrarily, L. praeflorens and L. subsessilis exhibited non-deep simple-type morphophysiological dormancy that requires relatively high temperature (≥ 15 ℃) for embryo growth and dormancy breaking. The optimum temperature for the germination of seeds of L. insularis, L. harae, L. praeflorens, and L. subsessilis was 15 ℃, 20 ℃, 15 ℃, and 20 ℃, respectively. There was interspecific variation in seed dormancy and germination patterns in the four Lonicera species. The difference in these characteristics within the four Lonicera species could be useful for understanding the seed ecophysiological mechanisms of Lonicera species.