• Journal of Aquaculture
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• v.12 no.1
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• pp.39-45
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• 1999

In order to obtain the basic biological data for artificial seedling production of sea cucumber, Stichopus japonicus, the influence of water temperature and air dry for spawning induction, egg development and larvae rearing was investigated during the period from April, 1995 through September, 1995. Spawning induction rate by the water temperature was 6.0~17.5% and air dry was responsed 1.4~4.0%. Number of eggs spawned of Stichopus japonicus were $50~500\times10^4$ individuals, the fertilization and hatching rate were ranged 84.0~96.0%, 71.4~84.6% respectively. The fertilized egg of Stichopus japonicus appeared mean diameter of $154{\mu}m$. At a constant water temperature of $23^{circ)C$, it become 4 tell stage from fertilization after 2 hours 10 minutes, hatching larvae after 14 hours half, auricularia larvae after 3 days, doliolaria larvare after 11 days and pentactula larvae after 15 days ready for settlement. The suitable food in the larvae reared for 17 days after fertilization were shown the best growth and survival in the larvae food of Chaetoceros calcitrans. Optimum density for larvae rearing were maintained of the larval density lower than 2 individuals/ml.

• Journal of Biosystems Engineering
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• v.28 no.2
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• pp.151-156
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• 2003

This study was performed to investigate the effect of light quality on evapotranspiration and graft-taking characteristics of watermelon grafted seedlings using blue, red and far-red light-emitting diodes (LED). At initial stage of graft-taking, blue light increased the evapotranspiration rate (EVTR) of grafted seedlings as compared to effects of red and far-red on EVTR of grafted seedlings. Grafted seedlings graft-taken under red and blue LED showed the high graft-taking of 100% and 96%, respectively. However, grafted seedlings graft-taken under far-red LED showed the graft-taking of 80% and survival of 60% with low seedlings quality after hardening. The stem of grafted seedlings graft-taken under red light was elongated but blue light suppressed the stem elongation. The leaf area of grafted seedlings graft-taken under red light was increased. It is concluded that the effect of light quality using LED on graft-taking of watermelon grafted seedlings was significantly recognized. Considering the duration of quality of grafted seedlings graft-taken under artificial lighting, LED could be used as an effective lighting sources to validate the continuance of seedling quality.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.5
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• pp.141-152
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• 2011

Cuttings based on water media are relatively low-cost and easy to manage compared to those based on soil media. Nevertheless, species that root out in water media are very few. Water-medium rooted cuttings are not widely used. In water media, the survival rate of cuttings is high, but in many cases, they only form callus while not rooting. If cuttings with callus formed in a water medium were to root and survive after being transplanted in soil, water-medium cuttings could be used as an important means of propagating landscape tree species. In this study, cuttings of Ternstroemia japonica having various reactions to water media were soaked in different types of water media. Their callus formation and rooting conditions were analyzed. The water-medium cutting swere then transplanted in soil, and conditions for their survival were examined. The study concluded: 1. Cuttings that only formed callus in water media were able to root and survive after being transplanted. 2. Cuttings with satisfactory callus formation showed more satisfactory survival conditions than those with unsatisfactory callus formation. 3. Cuttings rooted in water media showed a high survival rate of 96.6% after being transplanted. 4. Water-medium cutting of Ternstroemia japonica proved to be more effective in Late July or August than in late June. 5. Cuttings pre-treated in 50ppm-IBA for 24 hours showed better survival conditions than those that were not pre-treated inIBA. 6. Cuttings pre-treated in 50ppm-IBA for 24 hours and soaked in water media with 0.02% atonic, 0.02% polyoxin, and 0.01% polyoxin showed a rooting and survival rate of 80 to 85%. Regardless their low rooting rate, water-medium cuttings can show a high survival rate when these factors are considered: proper cutting time, plant hormone treatment, and types of water media. Accordingly, water-medium cuttings will emerge as major means of propagating landscape tree species that require small volumes of multi-species.

• The Korean Journal of Malacology
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• v.19 no.2
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• pp.133-142
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• 2003

For the effective seedling production of flat oyster, Ostrea denselamellosa, dietary value of live food, densities, water temperature and salinity on growth and survival rate of the larvae were examined. In rearing larvae by feeding them phytoplankton diets, the optimal survival rate and growth rate of larvae were found using a mixed phytoplankton diet which was mixed with Isochrysis galbana, Chaetoceros calcitrans and Chlorella sp. The highest growth and survival rates of the larvae were 208.4% and 38.8% with the phytoplankton diet. In growth and survival rates of larvae with various rearing densities, the highest survival and growth rates were 228.1% and 29.0% at the density of 2 individuals/ml. In observing rearing experiments of the flat oyster larvae under various temperature conditions, average growth rates of the larvae in respect to shell length were 202.2%, 240.4%, 250.6% and 121.3% in natural water temperatures (18-22$^{\circ}C$), 24$^{\circ}C$, 28$^{\circ}C$ and 32 $^{\circ}C$, respectively. And average survival rates of the larvae were 16.0%, 32.0%, 13.0% and 0% in natural water temperatures (18-22$^{\circ}C$), 24$^{\circ}C$, 28$^{\circ}C$ and 32$^{\circ}C$, respectively. In rearing at various salinities, the highest growth rates of the larvae in shell length was 240.0% at 30.0 psu and the highest survival rate was 31.0% at 25 psu.

• Journal of Korean Society of Forest Science
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• v.104 no.1
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• pp.90-97
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• 2015

The objective of this study was to find optimal amount of fertilization of container seedling production for Zelkova serrata, Ulmus parvifolia, Betula costata and Tilia amurensis. To reach our goal, we measured root collar diameter (RCD), height, biomass and seedling quality index (SQI) of container seedlings of four deciduous hardwood species grown at three different fertilization treatments ($0.5g{\cdot}L^{-1}$, $1.0g{\cdot}L^{-1}$ and $2.0g{\cdot}L^{-1}$). Z. serrata seedlings grown at $2.0g{\cdot}L^{-1}$ fertilization and B. costata seedlings grown at $0.5g{\cdot}L^{-1}$ fertilization showed the highest RCD, height, biomass and SQI. The RCD and height of U. parvifolia and T. amurensis seedlings showed no significant differences by fertilization treatments. Seedlings of two species at $0.5g{\cdot}L^{-1}$ fertilization showed the lowest SQI, however, SQI at 1.0 and $2.0g{\cdot}L^{-1}$ fertilization treatments were not significantly different. Based on these results, it is appeared that container seedlings of Z. serrata at minimum $2.0g{\cdot}L^{-1}$ fertilization, U. parvifolia and T. amurensis at $1.0g{\cdot}L^{-1}$ fertilization and B. costata at maximum $0.5g{\cdot}L^{-1}$ fertilization were optimal nutrient conditions. Practice of optimal fertilization rate will make us get better quality seedlings and reduction of production costs in the container nursery system as well as good field performances with higher survival rate after planting.

• Journal of Environmental Science International
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• v.28 no.12
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• pp.1061-1069
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• 2019

Common reed (Phragmites australis) is widespread in reclaimed land and wetland habitats. Every year, the common reed produces extensive colonies by means of underground rhizomes and ground-surface stolons. From an agricultural point of view, the common reed's large biomass is a good material for supplying organic matter. However, it has not yet been studied in terms of seedling production, transplanting conditions, and decomposition characteristics in reclaimed land. Seeds were harvested from the native common reed in Saemangeum, South Korea, the previous year and stored on an open field. The seeds were sowed in the greenhouse at the beginning of April. Common reed decomposition was studied from June to September, with the use of coarse mesh (5 mm) stem litterbags, on three samping dates and with five replicate packs per sample. These packs were dug in five soil condition (low-salinity topsoil, subsoil, high-salinity topsoil, subsoil, paddy topsoil) to 0.2 m and 0.4 m depth. The highest germination rate of common reed seeds was observed in non-salt solution, but the exhibited germination rate was 70% at 9.38 dS m^-1. The plant height of young reed decreased steadily with increasing salinity, but leaf number did not decrease by 9.38 dS m^-1. The survival rate of the two-year-old reed was 83.3%, which was 35% higher than that of the one-year reed. The transplant success rate was 0% in the no vinyl mulching in the soil, but the first year and second year seedlings survived rates were 63% and 83.3%, respectively, in vinyl mulching. Common reed decomposition rates were faster low salinity than high salinity. All nutrient contents were found to fluctuate significantly with time by soil conditions. We also need to study the growth rate of reed transplanting seedlings by soil moisture contents and the comparison of degradation in common reed tissues.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.43-49
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• 2014

This study was designed to determine the effect of red LEDs during healing and acclimatization process on the survival rate and quality of grafted tomato seedlings. Red LEDs and no light (darkness) were used for treating three rootstock cultivars, which are 'B-Blocking', 'Kanbarune', 'High-power' in healing room. Results showed that survival rates of grafted seedlings in red LEDs were higher than those in no light treatment. Significant variation on survival rates of rootstock cultivars was observed in no light treatment but there was not significant variation in red LEDs treatment. Light treatment also reduced the percentage of infected plants, except for the 'Kanbarune' cultivar. Seedling quality in red LEDs was better than that in no light treatment by improving growth parameters such as plant height, leaf length, leaf width, leaf area, fresh and dry weight of shoot and root. Light treatments and rootstock cultivars did not affect number of leaves, leaf chlorophyll value and T/R ratio of seedlings, but seedlings in red LEDs were significantly more compact than those in no light treatment. Moreover, the root morphology of seedlings such as total root surface area, total root length, and number of toot tips in red LEDs was also greater than that in no light treatment.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.189-197
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• 2012

This study was carried out to develop the improved useful mutants for yield or composition of stevia plants using the gamma ray or chemical mutagens treatments. The seeds of stevia 'Suwon No. 11' were irradiated up to 400 Gy of gamma ray. Chemical mutagens were treated on the seeds of the 'Suwon No. 11' using 0.07% colchicine, 10 mM sodium azide, or 10 mM NMU for various durations. The germination rate, and shoot and root growth of seedling were estimated at 30 days after gamma ray irradiation or chemical mutagen treatment, and the plant height, the number of branches, and leaf length and width were examined at 3 months after mutagenesis treatments. In the case of gamma ray treatments, the germination rate and early-stage growth were decreased as the increase of radiation dose, and the 50% lethal dose was found to be 200 Gy. the plant height was decreased as the increase of radiation dose, while the number of branches per plant and leaf length were increased. Leaf shape was modified to the relatively longer one compared to the control, which was identified more apparently at the treatments of higher than 150 Gy. In the treatment of chemical mutagens, the rate of germination and survival were decreased as the increase of incubation time. The 50% lethal dose for germination rate were identified as the conditions of the 15 hours incubation in 0.07% colchicine, the 4 hrs in 10 mM sodium azide, and the 2 hrs in 10 mM NMU, in the three chemical mutagens treatments. Chemical mutagens had no influence on shoot growth, while root growth was increased, especially as the incubation time was extended. The highest root growth occurred in the NMU treatment at 6 hrs incubation time. The plant height was decreased as the increase of incubation time in the chemical mutagens treatments. Among the chemical mutagens, NMU was the most effective to induce the mutants with long-shaped or the least lobed leaves.

• Journal of Korean Society of Forest Science
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• v.110 no.3
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• pp.406-418
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• 2021

This study was conducted to evaluate optimal storage techniques for bare root plants and container seedlings of Quercus variabilis and Zelkova serrata in order to maintain high quality of seedlings until planting. Refrigerated storage treatments were given at two temperatures (-2℃ [freezing] and 2℃ [cooling]) for nine different durations (0, 15, 30, 60, 120, 180, 240, 300, and 360 days after storage). We analyzed total nonstructural carbohydrate (TNC) content and measured shoot moisture content (SMC) during the storage stage and survival rate (SR) and dry weight during the planting stage of seedlings. The TNC content and SMC of the seedlings of the two species decreased with an increase in storage duration. The TNC content of seedlings rapidly decreased after 180~240 days of storage. The TNC reduction rate in the freezing treatment was lower than that in the cooling treatment. Also, with an increase in the storage duration of the two species, the SMC reduction rate in the cooling treatment increased in comparison with that in the freezing treatment. In both the species, the SR after planting decreased rapidly after 60 days of cooling storage and 180 days of freezing storage, respectively. The SR after planting was less than 60% when the TNC content for both the species dropped below 20 mg g^-1. In addition, the SR was lower than 80% when SMC measured before storage decreased by approximately 30% and 20% for Q. variabilis and Z. serrata, respectively. Our results suggest that cooling (1~2℃) storage is recommended for a short-term period (2 months or less), whereas freezing (-2~-4℃) storage is suitable for longer periods (2~6 months). These optimal storage techniques, allied with seedling harvesting and handling systems, will improve the quality of seedling production in nursery stages and increase seedling growth performances in plantations.

• Journal of Aquaculture
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• v.18 no.3
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• pp.142-146
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• 2005

In this study, the reattachment processes of small and medium size of spot of Mytilus coruscus and M. edulis were observed. The small spats (Shell length, SH, $3{\sim}7mm$) of hard shelled mussel, M. coruscus showed 100% reattachment rate within 7 minutes after the detachment of byssus thread and 100% survival rate. While large spats (SH 25 mm) showed 85% reattachment rate within 5 hours and 100% survival rate for 24 hours. The reattachment rate of M. edulis (SH 30 mm) was higher than that of M. coruscus (SH, 28 mm). The thread consisted of three identifiable structures; adhesive disc, adhesive thread and adhesive root. The adhesive disk and adhesive thread of M. coruscus were larger and thicker than those of M. edulis, whereas the thickness of adhesive root was the other way round. Further studies are required to identify the relationship between the structure of byssus thread and attachment ability. This study suggests that the sizes of spats could be an important factor in determining the timing of removing and reattaching mussel seedling for aquaculture or releasing to the sea.