• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.24-29
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• 1997

This study was conducted to evaluate the effect of locations and nursing days on the cstablishment and the first-year growth of Aster scaber seedlings in mountainous areas. Survival rates of the seedlings ranged from 72% in Bukbang to 27% in Mt. Yeonyup B. Survival rate of 90 days-seedlings was 65%. 150days-and 120days- seedling had 2 or 3 leaves but it was almost same as that of native plants. The plants grown in Mt. Yeonyup A averaged 10.7cm high and 90 days-seedlings grew best. Dry weight of plants grown from 120 days- and 90days- seedlings was respectively 215mg and 205mg.

• Journal of Forest and Environmental Science
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• v.29 no.2
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• pp.173-180
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• 2013

Berries of Korean mistletoe (Viscum album var. coloratum [Kom.] Ohwi) contained one seed, which have, in general, one or two embryos but very rarely three embryos. Mucilaginous substances in berries may help them adhere to the branches of host trees. It was observed that seeds need more than one and half years to develop into normal and healthy seedlings from the time of inoculation. Many factors such as adhesion of berry, thickness of host branch, orientation of haustorial root, etc. influenced the successful development of mistletoe plants. Through the application of six-year observation results on the germination of seeds and growth of seedlings, about 80% of germination rate for mistletoe seeds and 61% of survival ratio for germinated seeds, which is more than 23 times higher in natural conditions, were obtained after inoculation of seeds on the one-year-old branches of Malus pumila var. dulcissima and Quercus mongolica trees. The technological aspects of the success can be applied to other host plants and provide a critical clue to an artificial propagation system, for this medicinally valuable genus. This is the first successful report on artificial inoculation and plant development of Korean mistletoe.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.633-637
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• 2015

Cucumber and paprika transplants were stored at 9, 12, 15, and $18^{\circ}C$ under dark conditions for 15 days and then grown in a greenhouse for 14 days after transplanting. To determine the effects of low storage temperature and long-term continuous darkness on the quality and vigour of transplants, we investigated the quality of transplants during storage and the growth of stored transplants after transplanting. In cucumber transplants, decreasing storage temperature reduced stem elongation and decrease in SPAD value. The quality of cucumber transplants stored at $9^{\circ}C$ was well preserved during storage, but they did not survive after transplanting due to chilling damage. Growth and development after transplanting were significantly greater when cucumber transplants were stored at $12^{\circ}C$. In paprika transplants, the quality of transplants did not significantly differ before and after storage. After transplanting, there was no significant difference in the survival rate and growth, but the number of flower buds was greater in the paprika transplants stored at lower temperatures (9 and $12^{\circ}C$). These results indicate that the responses of transplants to the conditions of low temperature and darkness differed between cucumber and paprika, and storage temperature in darkness must be controlled carefully considering species-specific responses to reduce quality deterioration during storage and improve the recovery of transplants after transplanting.

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.313-319
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• 2012

Mass production method on artificial seedling production of hard clam Meretrix petechialis was developed indoor culture system. Spawning of adult clam (SL $65.8{\pm}8.4mm$) was induced using the combined method of air exposure and water temperature raising. The fertilized eggs were developed to D-shaped larvae after 17.7 hours at $27^{\circ}C$ and hatching rate was 6.1%. Shell length (SL) of D-shaped larvae was measured to be $131.4{\pm}2.6{\mu}m$ and thereafter the larvae grew to the settled spats with SL $190.2{\pm}7.5{\mu}m$ in 4 days. Estimated survival rate of settled spats was 48.1%. Spat collection on 130,000 spats with SL $0.19{\pm}0.01mm$ performed conducted by sand bottom circulation filtering method. Collected spats grew up to $3.1{\pm}0.8mm$ in 46 days, $6.6{\pm}1.8mm$ in 87 days, and $10.5{\pm}0.9mm$ in 114 days. The relative growth between SL and shell height (SH) was calculated to be SH = 0.8501SL + 0.0196 ($R^2=0.9987$) during the whole spat period. During spats rearing, they were suffered from one time of mass mortality at SL 3.1 mm, but 51,000 spats were finally survived with the rate of 39.2% at 114 days of spat rearing in indoor tank system.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.45-50
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• 2005

Virus-free stocks was produced by the combination of the heat treatment of virus infected plant and shoot-tip grafting (STS). To produce virus-free stocks, the plants infected with citrus viruses were used for virus-free stock production using the modified method of STG in thermotherapy at $40^{\circ}C$ for 16 hours in the light, and at $30^{\circ}C$ for 8 hours of darkness for 4 weeks. Trifoliate orange (P. trifoliata) were used as rootstock seedling for STG. Percentages of virus-free stocks against citrus tristeza virus (CTV), satsuma dwarf virus (SDV) and citrus tatter leaf virus (CTLV) were $75.7\%,\;100.0,\%\;82.6\%$ respectively. Shoot tip size for successful STG were as small as possible. Less than $0.3\;\cal{mm}$ of shoot tips gave the hight efficiency of virus free plants but survival rates were low. And, survival rate after shoot-tip culture was analyzed and the rates were dependant on the cultivars; Yuzu cultivar showed the hight survival rate ($74.6\%$) and early satsuma mandarin (Iwasagi) was $13.3\%$ as the lowest cultivar. But citrus trees were not succeed to grown, turned brown, and died.

• Korean Journal of Plant Resources
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• v.22 no.5
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• pp.394-402
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• 2009

Adventitious shoots were induced from pinnae, petiole and rhizome in Pteris cretica 'Wilsonii' in order to develop the efficient mass propagation method, using in vitro culture. Only homogenized rhizome segments could regenerate young sporophytes. Efficient regeneration of multiple shoots was obtained on the one-eighth strength MS medium containing 1% sucrose, and $50mg{\cdot}L^{-1}$ $NaH_2PO_4$. To achieve higher rate of regeneration from rhizome segments, rhizome segments were exposed to growth regulators for 2 months and then subcultured on hormone-free medium. The greatest shoot regeneration was obtained by $1{\mu}M$ kinetin with $5{\mu}M$ NAA. BA was effective in formation of GGB (kind of meristems), but they showed low shoot regeneration rate. Plants obtained from present experiments were transplanted to examine good environmental conditions for acclimation. Juvenile plants obtained by the one-eighth strength MS medium showed highest survival rate and vigorous growth at the seedling stage.

• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.210-216
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• 2023

Conventionally, the seeds of Rehmannia glutinosa (Gaertn.) Libosch. ex Steud. have been directly sown at the field without using the plug seedling method. Plug seedlings have the advantage of promoting germination and convenient transplanting. However, there is little information about propagation of R. glutinosa using the plug seedling method. This study was conducted to investigate the optimal seed rhizome length, diameter, and sowing direction of R. glutinosa for establishing the plug seedling method. Seed rhizome length and diameter were separated by 1, 2, 3 cm and 0.3-0.5, 0.6-1.0, 1.1-1.5 cm, respectively. And seed rhizomes were sown in vertical and horizontal directions. The survival rate in 1 cm length of seed rhizomes was lower than in other treatments. The leaf length, leaf width, number of leaves, SPAD, leaf area, and fresh and dry weights of shoot and roots were the greatest in 3 cm length of seed rhizomes. As the seed rhizome diameter decreased, the growth characteristics of R. glutinosa tended to increase. When R. glutinosa was sown horizontal direction, the leaf length, leaf width, number of leaves, and leaf area were significantly higher than in the vertical direction. In conclusion, when sowing seed rhizome in a plug tray, using a length of 3 cm, a diameter of less than 1 cm, and sowing in a horizontal direction is considered an appropriate sowing method for R. glutinosa.

• Journal of Korean Society of Forest Science
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• v.102 no.1
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• pp.66-73
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• 2013

This study was conducted to determine the effects of rice hull cover on seed germination and tray types, soil types, shading conditions for seedling growth of Codonopsis pilosuala. We also examined the feasibility of cultivation of small seedlings transplanted in the Gyeonggi-do area for a month. Under control condition, the seed germination was 8% whereas it dramatically increased to 78% under rice hull cover treatment. Under the different conditions (tray types, soil types, and shading conditions), young seedlings showed the best quality without shading in TKS soil of 50 plug cell tray, with the growth characteristics of plant height (11.9 cm), number of leaves (71), leaf width (3.1 cm), leaf length (2.6 cm), and root length (14.3 cm). Seedling quality was the best without any shading in TKS+perlite, with the physiological characteristics of evaporation (3.9 $mmol{\cdot}m^{-2}s^{-1}$), carbon assimilation (9.1 ${\mu}mol{\cdot}m^{-2}s^{-1}$), and water use efficiency (2.2 ${\mu}mol{\cdot}m^{-2}s^{-1}$). Considering the economical, morphological, physiological and survival rate of the seedlings, it was an ideal method for transplanting seedlings in the field after they have been grown for 30-45 days in TKS and TKS+perlite of 200 plug cell tray in 0% or 30% shaded conditions. As the results of 5 months examination on the possibility to cultivate Codonopsis pilosuala in the Gyeonggi-do area, 88% to 96% of survival rate was observed with normal induced flowers. Therefore, cultivation of Codonopsis pilosuala was possible in the Gyeonggi-do area. While there were symptoms of etiolation and wilting under no shading condition, they did not appear in 30% and 70% shading conditions. Therefore, cultivation of Codonopsis pilosuala is considered to be necessary 30% or 70% shading.

• Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.160-166
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• 2006

We explored the possibilities of using the freshwater rotifer Brachionus angularis as a live food for small fishes cultured in fresh- or brackish waters. Brachionus angularis were collected from a reservoir for isolation and laboratory culture. Length and width of the lorica were $102.3{\mu}m$ and $76.6{\mu}m$, respectively, and those of amictic eggs were $64.4{\mu}m\;and\;47.9{\mu}m$, respectively. When their growth rates were examined at six different temperatures, i.e., 15, 20, 25, 30, 35, and $40^{\circ}C$, the highest daily growth rate of 0.801 was observed at $35^{\circ}C$, and growth was lower with decreasing temperature. Adaptation to salinity change was evaluated with two different modes of salinity increase: step-wise elevation lasting for short durations of 5 to 30 min or a long duration of 24 h. With the short duration modes, no individuals survived salinity higher than 10 psu, and the number of live individuals did not increase throughout the experiment. However, in the 24-h elevation, the number of individuals increased when salinity was elevated by 1 to 2 psu per day for the first 2 or 3 days, while no increase in number occurred at salinity increments higher than 3 psu per day. In addition, to assess the effect of different diets, four single-component diets (Chlorella vulgaris, Nannochloris sp., baker's yeast, or dry yeast) and three combination diets (C. vulgaris + Nannochloris sp. + baker's yeast + dry yeast; C. vulgaris 70% + baker's yeast 30%; C. vulgaris 30% + baker's yeast 70%) were used. The specific growth rates of B. angularis fed combination diets were higher than those of rotifers fed any single-component diet, with the highest rate of 0.648 in B. angularis fed a mixture of C. vulgaris, Nannochloris sp., baker's yeast, and dry yeast, and the lowest rate of 0.200 in those fed dry yeast only. Our results indicate that the freshwater rotifer B. angularis can be used for seedling production of both freshwater and brackish-water fishes that require small (less than about $120{\mu}m$) live food during their early stages.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.153-162
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• 2010

Abies holophylla Maxim. is a shade tolerant species that has potential to be used for continuous cover forestry system. Stand structure and natural regeneration of A. holophylla stands in Yong-In area located in the central part of Korea was investigated to estimate the self sustainability of A. holophylla plantation. Species composition, diameter at breast height (DBH) and height distribution of trees larger than 2 cm DBH were measured in ten stands in three study sites of Jeongsu-ri, Daedae-ri, and Hodong. Species and coverage of shrub layer, and A. holophylla seedlings were also investigated. While A. holophylla in non-managed stands (Jengsuri and Daedae-ri study sites) had the importance value of 40% and showed continuous diameter and age distribution, A. holophylla in Hodong site had narrow bell-shaped DBH distribution mostly concentrating between 25-35 cm DBH classes, and single canopy structure. Abies holophylla stands in Hodong have experienced occasional thinning and selective cutting. The correlation coefficient between age-DBH was significant but low ($R^2$=0.2, P=0.03), and similar aged A. holophylla had diverse DBH values. Continuos DBH distribution and multi-canopy structure of A. holophylla stands in Jeongsu-ri site show that natural regeneration of A. holophylla has been continuously occurred in this area. Seedling density of A. holophylla was between 2000 and 33000/ha, however, the number of trees in 2-5 cm DBH class was only 40-150 trees/ha, implying that the survival rate of seedlings is not high. Continuous natural regeneration and 0.6 cm/year of diameter growth rate of A. holophylla indicate that this area could be an appropriate habitat for this species, and A. holophylla plantation in this region seem to persist suggesting the possibility of managing the stands for continuous cover forestry system as well as selective harvesting practices.