• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.65-75
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• 2002

The study was carried out to determine the growth and biomass production of major deciduous trees including Betula platyphylla var. japonica, Betula schmidtii, Zelkova serrata, Acer mono, Prunes sargentii, and Ligustrum obtusifolium subjected to artificial shade treatment in nursery field. The six deciduous trees seedlings grow for 2 years under different light intensity of 100%, 38-62%, 22-28%, 7-20%, and 2-6% of the full sun light intensity. The results were as follows; In the seedling heights and root collar diameters of shade intolerant species like Betula platyphylla var. japonica and Betula schmidtii, the relative growth rates of seedlings grown in full sun showed 2 times as compared with those subjected to the shade treatment of 2-6% light intensities of full sun. In the shade tolerant species like Acer mono ant Ligustrum obtusifolium, the growth performances were better in the seedlings grown in 38-62% light intensities of full sun. Total dry mass including the dry mass of leaves, shoot and root were as a whole decreased with shade treatment. The ratio of the dry mass of leaves and stem increased the dry mass of root. T/R ratio of the seedlings increased by decreasing the relative light intensity. And the T/R ratio of 2-6% light intensities of full sun was ranged from 1.1~5.0 were greater in the full sun light was ranged from 0.6~3.2. Light intensity by artificial shade treatment decreased in deciduous trees when compared on the whole, it showed tendency that SLA increases, increased that seeing resemblant tendency in LAR and LWR and changed of light intensity is strong, it increased that showed difference as statistical. But, LWR of Betula platyphylla var. japonica increased gradually and showed tendency that decreases rapidly in the shade treatment of 2-6% light intensities of full sun. This result is thought that biomass production decreased by shading treatment influenced in physiological characteristics such as leaf area and decrease of the leaf amount.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.407-414
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• 2018

This study was aimed to evaluate the effect of application method and concentration of gibberellin $A_3$ ($GA_3$) on the growth, runner production, and seedling quality of strawberry plants (Fragaria ${\times}$ ananassa Duch. cv. Maehyang) during nursery period. The mother plants of strawberry were transplanted in pot ($64{\times}27{\times}18cm$) filled with commercial growing medium on March 20, 2018. $GA_3$ concentration was applied as 0, 50, 100 or $200mg{\cdot}L^{-1}$ with spray or drench to 45 mL per plant at 4 weeks after transplanting, respectively. Nutrient solution was supplied with the EC $1.5dS{\cdot}m^{-1}$ after the transplanting and supplied 350 mL per pot twice a day (15 min per one time) after rooting. The growth characteristics of mother plants of strawberry were measured at 7 weeks after treatment, and growth characteristics of daughter plants of strawberry were measured at 10 weeks after treatment. Runner length and diameter of mother plant was the longest or thickest in the spray with $200mg{\cdot}L^{-1}$ than the other treatments, respectively. Soil-plant analysis development (SPAD) value of mother plant was the lowest in spray with $200mg{\cdot}L^{-1}$. However, leaf length, leaf width, and crown diameter showed no significant differences in all treatment among application method and concentration of $GA_3$. As the concentration of $GA_3$ increased, physiological disorder like stretchiness of crown occurred more. The physiological disorder was the most occurred in spray treatment with $200mg{\cdot}L^{-1}$, but drench treatment occurred less than spray treatment. The number of runners and daughter plants increased with increasing concentration of $GA_3$ regardless of application methods. In the growth characteristics of the daughter plants, leaf length and leaf width of first daughter plant, plant height, crown diameter, leaf area and SPAD value of second daughter plant, and plant height of third daughter plant were the significantly greatest in drench with $100mg{\cdot}L^{-1}$ treatment. This results indicate that growth and runner production of mother plants and growth of daughter plants of strawberry were the best achieved by drench application in the $100mg{\cdot}L^{-1}$ $GA_3$.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.48-67
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• 2021

Plant species exhibit current characteristics as a result of interactions with environmental conditions. The plants of Viola sp. have selected chasmogamous flowers with vigorous vegetative propagation or development of cleistogamous flowers as an adaptation strategy. Viola websteri is distributed on the Korean peninsula and the eastern part of Jilin Province, China. The center and edge of the distribution are expected to exhibit different population-dynamics. It is necessary to investigate the cause of its current limited distribution even though V. websteri has a mixed-mating strategy. Firstly, We examined the vegetation environment of habitats and evaluated its characteristics. Growth characteristics were examined through plant phenology. We then evaluated the population structure, characteristics of chasmogamous flowers, and productivity of cleistogamous flowers. Moreover, we compared population sizes between 2014 and 2018. Most habitats were located in deciduous broadleaf mixed forests adjacent to valleys. V. websteri produced chasmogamous flowers with self-incompatibility in April-May and cleistogamous flowers in June-September. The cleistogamous flower production is a strategy ensuring seed production under uncertain environmental fluctuations; these were approximately twice as numerous as chasmogamous flowers. The population structure was distinguished into stable and very unstable regions. There were sites where the population experienced a sharp decline in the 2018 compared to that of 2014. This large decline was found in the edge populations. The habitats had different microsites depending on the natural disturbances of drought and the matrix constituting the habitat, thus supporting various plants. Ensuring the production of seeds through cleistogamous flowers, it was determined that rapid seedling re-establishment and population replenishment were possible when the natural disturbance factor was removed. Environmental factors did not equally affect all populations or individuals. Therefore, it was expected that it would be able to persisted in a long time, despite the rapid decrease in the number of individuals in the population regionally. Local extinction and re-establishment are likely to repeat according to environmental change. We propose the additional population investigation based on this works are required. We also suggest a need to assess the long-term population dynamics and the genetic characteristics of chasmogamous flowers and cleistogamous flowers to establish and implement effective conservation strategies.

• Journal of Aquaculture
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• v.7 no.4
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• pp.225-237
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• 1994

Survival and growth rates of flounder larvae fed rotifers and Artemia nauplii enriched by various bio-enrichment techniques were investigated. Enriched materials used in the study were $12\omega-yeast$, 2 commercial emulsified oil and microparticulated products. $\omega-yeast$ were added with one kinds of oils (cuttlefish liver oil, sardine oil, Alaska pollock liver oil, linseed oil) at the level of $5\%,\;15\%\;and\;25\%$. The results are as follows: 1. The growth rate of rotifers cultured with $\omega-yeast$ added $15\%$ cuttlefish liver oil was the best among 12 kinds of $\omega-yeast$ and this performance was almost the same with that of rotifers fed on Chlorella. 2. Survival and growth rates of flounder larvae fed on rotifers and Artemia nauplii enriched with $\omega-yeast$ and the other commercial products were higher than that those of larvae cultured with only Chlorella and non-enriched Artemia. The optimum contents of the cuttlefish liver oil in $\omega-yeast$ for rotifers and Artemia enrichment were $15\%\;and\;25\%$, respectively. 3. Optimum enrichment time and supply amount of $\omega-yeast$ for Artemia nauplii were 6 hr., 1.5 g/g cyst, respectively.

• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.47-53
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• 1977

Bacterial diseases of soybean has been recognized as a limiting factor of soybean production in Korea as it was estimated to cause around 10 percent of yield losses annually. The purpose of the study is to obtain information on the diseases through proving the kinds of pathogens and epidemiology, The wire brush method and multineedle appeared to be the best way of inoculation under all circumstances. Wire brush method, especially, was effective in shortening the incubation period and manifesting the lesion development by introducing more inoculum per unit of area. In case of spray inoculation it was necessary to apply a small amount(1 : 1,000) of wetting agent, twin-20, otherwise it was unabled to produce the diseases under field conditions. Two kinds of bacterial diseases caused by Pseudomonas glycinea and Xanthomonas phaseoli var. sljense were found from surveyed areas in Kore. Wild fire disease on soybean caused by Pseudomonas tabaci had not detectable during the experiment although there were several reports on the disease from other countries. when the pathogens were introduced into sterile soil, bacterial leaf blight pathogen could exsisted until 30 days while bacterial pustule pathogen survived only 4 days under the natural conditions of later June. Both bacteria, however, could produce the disease after more than 10 months period of storage in refrigerator when they were exsisted in infected plant tissues. In warehouse, non-temperature controlled, the bacteria lose their infectability within 6 months period from October to April even though they exsisted in infected tissues. Surface infested seeds with the pathogens could not produced the diseases on seedling stages of soybean plants when the seeds were planted in sterile soil after inoculation by dipping the seeds into bacterial suspensions, although germination was depressed by the pathogens when the seeds were planted on agar media.

• Korean Journal of Ichthyology
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• v.21 no.3
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• pp.158-166
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• 2009

To obtain the fundamental data for the mass seedling production of grunt, Hapalogenys nitens, we investigated the influence of salinity and cold water temperature on hatching and survival of eggs and growth and survival of larvae and fry. In regards to salinity, we surveyed the hatching rate and floating rate of fertilized eggs, the floating rate and survival rate of hatching larvae, and the survival and growth of fry. In respect to cold temperature, we investigated the influence of degree of daily temperature decrease, acute temperature shock, and slow temperature decreases on the survival, feeding and swimming activities of fry. In the salinity experiment, the hatching and floating rates of fertilized eggs, and the floating and survival rates of hatching larvae, were shown to be higher in seawater than in brackish water. Growth and survival of larvae and fry were not different between seawater (25~32 psu) and brackish water (5~20 psu), but were significantly lower in freshwater. In the cold-temperature test, three tests showed that rearing of fry in cold water and acutely decreasing water temperature to less than $10^{\circ}C$ reduced the survival, feeding and swimming activities of the fry. Therefore, we concluded that low salinity (less than 32 psu) could reduce the hatching rate and survival of eggs, but the growth and survival of fry were not influenced by salinity, and cold water (less than $10^{\circ}C$) decreased metabolism of grunt. During winter, we found a low-temperature limit at $8^{\circ}C$.

• Korean Journal of Ichthyology
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• v.21 no.4
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• pp.221-226
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• 2009

Six microsatellite DNA markers were used to investigate the genetic variability between wild populations and cultured stocks of olive flounder Paralichthys olivaceus. The average of observed (Ho) and expected heterozygosity (He) ranged from 0.722 to 0.959, and from 0.735 to 0.937, respectively. There was no distinguishable difference between the wild populations and cultured stocks in terms of the observed and expected heterozygosities. However, number of alleles per locus differed markedly between the two fish groups: 19.7 to 21.8 for the wild populations and 12.0 to 14.7 for the cultured stocks. This result gives important information concerning the production of seedling for the improvement of genetic diversity in this species.

• Journal of Life Science
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• v.30 no.3
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• pp.291-297
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• 2020

This study was conducted to develop microsatellite markers in Seriola quinqueradiata using next-generation sequencing. A total of 28,873,374 reads were generated on an Illumina Hiseq2500 system, yielding 7,247,216,874 bp sequences. The de novo assembly resulted in 466,359 contigs. A total of 132 contigs (0.43%), including 60 microsatellite loci, were derived from 30,729 contigs longer than 518 bp. A total of 60 primer sets were designed from the 132 microsatellite loci. A total of 15 polymorphic nuclear microsatellite loci were chosen to evaluate population genetic parameters in the parents and offspring. The mean number of effective alleles was 18.5, ranging from 11 to 30. The observed heterozygosity (H_O) and expected heterozygosity (H_E) ranged between 0.431 and 0.972 with an average of 0.812 and from 0.782 to 0.949 with an average of 0.896, respectively. No significant linkage disequilibrium was observed after Bonferroni revision in any loci. The results show that the 15 polymorphic nuclear microsatellite markers can be used to study the population and conservation genetics of S. quinqueradiata in Korea. To ensure the success of artificial seedling production technology, genetic variations between the parent and offspring populations should be monitored, and inbreeding should be controlled.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.3
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• pp.127-132
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• 2006

This experiment was conducted to evaluate the effect of manure and chemical fertilizer on the forage yield and quality of oat at no-tillage. The experimental design was a randomized complete block design. The three treatments were: chemical fertilizer, manure fertilizer, and chemical and manure mixture. Seedling vigor was higher at chemical fertilizer than manure, but more greener at manure application than chemical fertilizer. Dry matter (DM) content of oat at manure was higher than chemical and mixture fertilizer (p<0.05). There was no difference in DM yield, TDN (total digestible nutrients) yield, and CP (crude protein) yield of oat at no-tillage system, but the fresh yield was significantly higher in chemical fertilizer compared to manure. The CP content for oat was significantly higher in manure than chemical fertilizer. However, no significant effects were observed for NDF (neutral detergent fiber), ADF (acid detergent fiber), TDN and RFV (relative feed value) in different fertilizer application. Based on the results of this study, manure don't affected forage production and quality of no-till oat except CP content because forage oat is used off-season crop.

• Journal of Aquaculture
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• v.8 no.4
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• pp.307-316
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• 1995

Jicon scallop (Chlamys farreri), as one of new culture species, has been taken a growing interest in Korea recently. Artificial seeds are needed since seeds in natural waters are absolutely short. To develop the better methods for the artificial spawning and the rearing larvae on a large scale, experiments were carried out from July 1993 to May 1994. Mother shells were collected from the area near Tong-yeong and Geoje-do, the southern part of the Korean Penninsula. It was estimated that a period of 2-years was needed to be mother shells after the fertilization. Generally, spawning occourred intermittently from March to August and the maximum occurred in July. A best way for the artificial spawning was a chemical incentive, a 'serotonin injection' in parallel with the exposure and the temperature stimulation. Densities of the fertilized eggs for the normal development was from 30 to 40 per mililiter. It took 27-days from the fertilization to the settling larva averaging $155{\mu}m$ in size with water temperature 11.5\~13.0^{\circ}C$. Isochrysis galvana and Chaetoceros calcitrans with a density of $1,500\times10^4$ cells per ililiter were supplied for rearing the larvae. A proper density of larvae was 10 individuals per mililiter, and the survival rate of larvae from the flowing water system was much better than that of larvae from the still water.