• Journal of The Korean Society of Grassland and Forage Science
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• 제27권4호
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• pp.235-240
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• 2007

Optimum tissue culture conditions for an efficient induction of embryogenic callus from mature seeds of perennial ryegrass (Lolium perenne L.) and regeneration of plants from callus tissues were investigated. MS medium containing 3 mg/L 2,4-D and 0.1 mg/L BA was optimal for embryogenic callus induction from mature seeds. The highest plant regeneration frequency (58.3%) was observed when the embryogenic callus tissues were cultured on N6 medium supplemented with 1 mg/L 2,4-D and 3 mg/L BA. Regenerated plants were grown normally when shoots transplanted to the soil. A short tissue culture period and high-frequency regeneration system would be helpful for molecular breeding of perennial ryegrass through Agrobacterium-mediated genetic transformation.

• Korean Journal of Agricultural and Forest Meteorology
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• 제3권4호
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• pp.220-237
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• 2001

Over the 20th century global temperature increase has been 0.6$^{\circ}C$. The globally averaged surface temperature is projected to increase by 1.4 to 5.8$^{\circ}C$ over the period 1990 to 2100. Nearly all land areas will have higher maximum temperature and minimum temperature, and fewer cold days and frost days. More intense precipitation events will take plate over many areas. Over most mid-latitude continental interiors will have increased summer continental drying and associated risk of drought. By 2100, if the annual surface temperature increase is 3.5$^{\circ}C$, we will have 15.9$^{\circ}C$ from 12.4$^{\circ}C$ at present. Also the annual precipitation will range 1,118-2,447 mm from 972-1,841 mm at present in Korea. Consequently the average crop periods for summer crops will be 250 days that prolonged 32 days than at present. In the case of gradual increase of global warming, an annual crop can be adapted to the changing climate through the selection of filial generations in breeding process. The perennial crops such as an apple should be shifted the chief producing place to northern or high latitude areas where below 13.5$^{\circ}C$ of the annual surface temperature. If global warming happens suddenly over the threshold atmospheric greenhouse gases, then all ecosystems will have tremendous disturbance. Agricultural land-use plan, which state that farmers decide what to plant, based on their climate-based advantages. Therefore, farmers will mitigate possible negative imparts associated with the climate change. The farmers will have application to use agricultural meteorological information system, and agricultural long-range weather forecast system for their agroecosystems management. The ideal types of crops under $CO_2$ increase and climate change conditions are considered that ecological characteristics need indispensable to accomplish the sustainable agriculture as the diversification of genetic resources from yield-oriented to biomass-oriented characteristics with higher potential of $CO_2$ absorption and primary production. In addition, a heat-and-cold tolerance, a pest resistance, an environmental adaptability, and production stability should be also incorporated collectively into integrated agroecosystem.

• Korean Journal of Animal Reproduction
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• 제17권4호
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• pp.325-329
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• 1994

Seasonal and diurnal variation in serum testosterone was measured by radioimmunossary in 3 mature Korean native male goats. Blood was collected at 3-h intervals for 24h in each season. Mean levels of 4 seasons ranged from 0.82 to 2.06ng/ml and no difference was among seasons, although level in fall and winter was slightly higher. Diurnal level tended to increase at daytime in all season and when diurnal variation in level was compared to daily mean of each season, level of daytime greatly(P<0.05) increased in summer. However, variation between light and dark period in other seasons did not show significant difference. Daytime increase of testosterone was found 3 to 4 after dawn and level increased 1 to 2h ahead in summer and fall than that in others. These results in serum testosterone suggest that there was no great seasonal variation in endocrine function of goat testis.

• Korean Journal of Environmental Biology
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• 제32권3호
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• pp.263-269
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• 2014

In this study, I investigated the species composition in the Mulberry tree cultivation area from April 2013 to March 2014 at Busan. Five genera and nine species found are as follows: Aporrectodea caliginosa (Savigny, 1826), Bimastos parvus (Eisen, 1874), Eisenia fetida (Savigny, 1826), Drawida japonica (Michaelsen, 1892), Amynthas heteropodus (Goto&Hatai, 1898), Amynthas agrestis (Goto & Hatai, 1899), Amynthas corticis (Kinberg, 1867), Amynthas hilgendorfi (Michaelsen, 1895), and Amynthas sp. A total of 317 individuals of Aporrectodea caliginosa (Savigny, 1826) was collected. Ap. caligionosa and A. heteropodus were found to be the most dominant species during the study period. Interestingly, the maximum population density of Ap. caligionosa was recorded to be in the month of October. Further details analysis indicated that, its population increased rapidly during the breeding season between summer and autumn and thereafter gradually decreased through winter toward the following February. Three growth stages of Ap. caligionosa occurred almost simultaneously with abundance composition of 76% in aclitellum, 12.6% in semiclitellum, and 11.4% in clitellum. Based on my study results, I suggest that this data could be useful for the scientific community to analyze the distribution of southern earthworm species in mulberry tree cultivation area.

• Applied Microscopy
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• 제22권2호
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• pp.97-117
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• 1992

In order to study process of spermiogenesis of the Korean greater horseshoe bat, Rhinolophus ferrumequinum korai, the cycle of seminiferous epithelium was examined by the light and electron microscope and the following results were obtained based on the epithelial cell differentiation. 1. Spermiogenesis occurred from early July to mid-Octber, and spermatogenic activity was vigorous from mid-August to late September. Spermatocytes including spermatogonia were found to be degenerated in only July. It is deduced that the degeneration serves as the mechanism to regulate effective use of energy to prepare for mating and hibernating periods, and regulation of breeding cycle. 2. Spermiogenesis of the Korean greater horseshoe bat was divided according to differentiation of the cell structure, into Golgi, cap, acrosome, maturation and spermiation phases; Golgi, cap and spermiation phases were further divided into two steps of early and late phase respectively, and acrosome phase into three steps of early, mid and late phases, and maturation phase has only one step. Hence, the spermiogenesis consists of ten phases. The first research was done in this article on the changes of chromatin with nucleus, the time of appearance and disappearance of chromatin granules, in case of Korean greater horseshoe bat (Rhinolophus ferrumequinum korai). Chromatin granule began to be condensed in late Golgi and the condensation proceeded to form an irregular mass of a electron-dense chromatin in a form of circular cylinder in the center of nucleus at the phase of maturation. Finally, the chromatin condensation proceeded and perfect nucleus of sperm with homogeneous density was formed when the sperm was separated from Sertoli cell. Therefore, appearance and disappearance of chromatin granules occurred in the period of time between late Golgi and maturation phase, The tail of sperm began to develop in early cap phase, Numerous lipid droplets were obseved in the cytoplasm of spermatids during the maturation phase, which seemed to be used as energy source necessary to make mature sperm during spermiogenesis.

• Journal of the Korean Society of Environmental Restoration Technology
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• 제13권2호
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• pp.124-137
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• 2010

This study was started with the objective of restoring abandoned embanked farms, which are recently increasing, to mud flat by putting in least amount of energy in the aspect of environmental restoration. For the direction and establishment of the proposal for the restoration of mud flat using embanked farms, a case of Maipo Wetland in Hongkong was analyzed, and a proposal was prepared considering the condition of mud flat in Gochang. The restoration of mud flat in Gochang is intended to create various wetland ecological spaces as well as to provide opportunities for experience, education, recreation, and tourism. Effort was made to development an environment closest to the local ecological environment considering the shape and topographical condition of existing abandoned farms. For construction of the habitat, a target species was chosen and the plan for selection, planting, and management of species of trees suitable for the target species was established. In addition, the water level will be controlled by water gates to conform to the resting, spawning, breeding, and migration period considering the behavioral pattern of waders, the target species. The research on the restoration of mud flat in Korea is in incipient stage and this study provided an opportunity to review the possibility of restoration of abandoned embanked farms to mud flat. For the success of mud flat restoration from a long-term perspective, development of acclimating design infrastructure, technology improvement for mud flat restoration, and basis of partnership for the maintenance should be prepared in a systematical way.

• Korean Journal of Agricultural Science
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• 제40권3호
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• pp.177-182
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• 2013

A genus Camelina has been attracted as a promising oil crop, especially available in drought and marginal conditions. Due to more demands on arable land for bioenergy crops, price of agricultural products has been a challengeable issue. In that respect, development of Camelina crop with higher germination rate and germination energy can be a strategy to secure seedling establishment, nutrient uptake and long vegetative period. In order to be easily available in the field and laboratory conditions, Camelina seed needs to be optimized for its germination temperature. Germination temperature regime was in a range of 8 to $32^{\circ}C$ initially, and consecutively narrowed down to 8 to $20^{\circ}C$. Based on the temperature range, Camelina germinated greater than 96% at $8-16^{\circ}C$ in two weeks after sowing, but germination rate started to decrease at the higher than $24^{\circ}C$ and was significantly low at higher than $32^{\circ}C$. In terms of rapid time to reach the maximum germination rate and greater germination energy, temperature ranged from 12 to $16^{\circ}C$ was found to be desirable for Camelina germination. Although germinationa rate was greater at $16^{\circ}C$, lower temperature close to $12^{\circ}C$ would be favored for the field conditions where greater root growth leading to healthier seedlings and better nutrient or water availability is considerably demanded.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 한국환경생태학회 2007년도 정기총회 및 학술논문발표회
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• pp.136-142
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• 2007

The main aim of this study is to estimate home-range of the Korean raccoon dog(Nyctereutes procyonoides koreensis) at a rural area of Gurye in the southern part of South Korea. A radio-tracking was regularly carried out on 4 raccoon dogs for 2 days every 2 months in 2006. During the days, the radio-tracking was usually conducted every 1-3 hours through day-time to night-time. Among the 4 raccoon dogs, 2 individuals(a permanent breeding pair) could be extensively tracked for 5 to 7 months, including all 4 seasons. The result showed that total home-range sizes of the pair were 0.732 $km^2$ and 0.373 $km^2$ for 100% minimum convex polygons(MCP) and 100% kernel(K), respectively, during the monitoring period. Mean home-range sizes of the 2 raccoon dogs were 0.035-0,688 $km^2$ and 0.012-0.341 $km^2$ for MCP and K, respectively. Yearly home-range sizes of the male and female were similar to each other. However, home-range sizes of the raccoon dogs between day-time and night-time were quite different. Furthermore, the raccoon dogs showed a much broader home-range size in spring, summer and fall than in winter season. Finally, the pair had a broad overlapping home-range(about 70-95%), and 1 core area and 4 different feeding areas.

• Journal of Ginseng Research
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• 제44권2호
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• pp.312-320
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• 2020

Background: Ginseng (Panax ginseng Meyer) is an essential source of pharmaceuticals and functional foods. Ginseng productivity has been compromised by high light (HL) stress, which is one of the major abiotic stresses during the ginseng cultivation period. The genetic improvement for HL tolerance in ginseng could be facilitated by analyzing its genetic and molecular characteristics associated with HL stress. Methods: Genome-wide analysis of gene expression was performed under HL and recovery conditions in 1-year-old Korean ginseng (P. ginseng cv. Chunpoong) using the Illumina HiSeq platform. After de novo assembly of transcripts, we performed expression profiling and identified differentially expressed genes (DEGs). Furthermore, putative functions of identified DEGs were explored using Gene Ontology terms and Kyoto Encyclopedia of Genes and Genome pathway enrichment analysis. Results: A total of 438 highly expressed DEGs in response to HL stress were identified and selected from 29,184 representative transcripts. Among the DEGs, 326 and 114 transcripts were upregulated and downregulated, respectively. Based on the functional analysis, most upregulated and a significant number of downregulated transcripts were related to stress responses and cellular metabolic processes, respectively. Conclusion: Transcriptome profiling could be a strategy to comprehensively elucidate the genetic and molecular mechanisms of HL tolerance and susceptibility. This study would provide a foundation for developing breeding and metabolic engineering strategies to improve the environmental stress tolerance of ginseng.

• Development and Reproduction
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• 제21권4호
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• pp.399-406
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• 2017

This study was conducted to investigate egg development and larvae morphological development of catfish and to provide basic data to clarify the genetic relationship with Siluriformes fish. The mother fish that was used in this study was caught in the stream of Nakdong River in Uiseong-gun, Gyeongbuk. The temperature range of the breeding was $23.0-25.0^{\circ}C$ (mean $24.0{\pm}1.0^{\circ}C$) and egg size was 1.62-1.70 mm (mean $1.66{\pm}0.05$, n=30). Eggs of catfish began hatching at 54 hours and 40 minutes after fertilization. Immediately after hatching, the total length of larvae was 3.60-3.65 mm (mean $3.62{\pm}0.03$, n=5) and had an egg yolk without swimming ability. On the third day after hatching, the larvae at the medium stage was 8.00-8.65 mm (mean $8.32{\pm}0.45$) in total length, and two pairs of whiskers formed around the mouth were elongated. On the 12th day after hatching, the larvae at the juvenile stage was 16.5-17.0 mm (mean $16.7{\pm}0.35$) in total length, and the stem of each fin was in the range, and the juvenile at this period was morphologically similar to the mother fish.