• Journal of Aquaculture
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• v.16 no.3
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• pp.129-134
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• 2003

Spawning induction and early growth of the sea urchin, Strongylocentrotus intermedius were studied with the purpose of artificial seedling production. Gonadosomatic index(GSI) of the sea urchin showed the highest value in October, and rapidly decreased in December. It means that October and November is the peak of spawning season of the sea urchin in the latitude. Spawning induction by injection of potassium chloride solution in October has showed 44.0~100.0% reaction rate, and were produced 6,300$\times$10$^4$ eggs. Spawned eggs have shown the fertilization rate of 92.3~98.2% and the hatching rate of 78.2~87.0%. The metamorphosis of larvae after hatching in the seawater temperature of 13.7~17.1$^{\circ}C$ resulted in early eight-armed larvae in 13 days and late eight-armed larvae in 20 days. The collection of progenies was possible in 24~25 days after hatching and collection rate was 18.5~26.1% (mean 22.3%). Test diameter immediately after collection had a mean 350 ${\mu}{\textrm}{m}$. Survival rate and test diameter of juvenile sea urchin after collection were 58.5%, 1.32 mm in 30 days, 27.7%, 3.82 mm in 92 days and 15.6%, 11.70 mm in 181 days, respectively.

• The Korean Journal of Malacology
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• v.31 no.1
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• pp.35-41
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• 2015

In order to investigate the live food value of microalgae for efficacious rearing of larvae and spats of bivalve, we studied growth rates of four microalgal species (Isochrysis galbana, Pavlova lutheri, Chaetoceros simplex, Tetraselmis tetrathele) cultured in different environmental conditions. These include changes in temperatures (20, 25, 30 and $35^{\circ}C$), salinities (20, 25, 30 and 33 psu) and light intensities (60, 100 and $140{\mu}mol\;m^{-2}s^{-1}$). The growth rate of I. galbana was faster at $25^{\circ}C$ than that of $20^{\circ}C$. At $25^{\circ}C$ the highest growth rate of I. galbana was observed at 33 psu (0.413) and the lowest at 20 psu (0.368) in 10 days of culture (P < 0.05). The growth rate of I. galbana was lower at 25 psu (0.383) than that of 30 psu and higher than that of 20 psu (P < 0.05). Similar temperature and salinity-dependent changes were also found in P. lutheri and T. tetrathele. C. simplex showed faster growth rate at $30^{\circ}C$ than that of $25^{\circ}C$. The highest growth rate of C. simplex was observed at 33 psu (0.428) and the lowest at 20 psu (0.389) in 10 days of culture (P < 0.05). Upon exposure to the light with different intensities, all four microalgal species showed a significantly faster growth rate at $140{\mu}mol\;m^{-2}s^{-1}$ than at $100{\mu}mol\;m^{-2}s^{-1}$ (P < 0.05).

• Korean Journal of Medicinal Crop Science
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• v.6 no.3
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• pp.210-215
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• 1998

Solomon's seal (Polygonatum odoratum) was traditionally propagated by its rhizomes but seed propagation has not been practiced due to their dormancy and high price. To improve the seedling production through seed pretreatments, the experiment was conducted to determine the effect of seedcoat softening and seed prechilling on seed germination and bulbil formation of the seal. The prechilling was done for 4 to 16 weeks at $3^{\circ}C$ and the softening was forced with 10% KOH for 40 minutes. Seed germination, bulbil formation and length, no. of root and root length were measured at 6 and 12 weeks after sowing. Seed germination and bulbil formation were greater at 8 to 12 week prechilling than at shorter or longer treatment when only the prechilling was enforced. Prechilling had greater effect compared to seed coat softening. In addition, the softening treatment before prechilling showed higher germination and bulbil formation compared to single treatment of them. The softening treatment prior to prechilling was better than the reverse treatment in number of root except the above two characters. Duration of prechilling treatment was able to be shortened below 8 weeks when the softening treatment was applied before prechilling.

• Korean Journal of Medicinal Crop Science
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• v.20 no.2
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• pp.124-128
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• 2012

When ginseng seedlings are cultured in paddy fields, quality degradation and yield reduction are induced by severe plant loss with chlorosis on leaves occurred physiological disorder by excessive salt and poor drainage, rusty-root occurrence, and root rot etc. Accordingly, in order to solve these problems, this study was performed to investigate the treatment method, concentrations and time of activated ion calcium as environment-friendly agricultural materials. Activated ion calcium is an enriched and purified water-soluble mineral calcium component for absorbing quickly into plant as a highly functional calcium and it is an alkaline calcium of 37% (370 $m{\ell}$/1 ${\ell}$) concentration with pH 13. Treatment method was that ginseng seeds were sown after removing water in the shade after seed immersion for 1 minute with active ion calcium of 20-fold diluted solution, and then irrigated $4{\ell}$ per 3.3 $m^2$ with 200-fold, 400-fold, and 600-fold diluted solution before emergence on late March, and supplied 1 time on leaves with 500-fold diluted solution in June and July respectively. The disease rate by treatment of activated ion calcium was that on the treatment of soil irrigated with 200-fold diluted solution compared to non-treated soil, damping-off was 33%, anthracnose was 100% reduced and the occurrence rate of rusty-root was 30% reduced. In addition, when active ion calcium of 200-fold diluted solution were soil irrigated, first and second grade ginseng were respectively 26% and 22% produced more, compared with control.

• Journal of Aquaculture
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• v.10 no.1
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• pp.25-32
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• 1997

Develoment precess and characteristics of eggs of the geoduck clam, Panope japonica are reporting in this study. Eggs and sperm were excised from gonad, artificially fertilized in an aquarium, reared under various temperature regimes, and record and record the larval period and the time need to reach a certain larval stage from ferilization. Unfertilized eggs of P. japonica appeared to be oval with a mean diameter of $70\mu$m and they became spherical after fertilization. The eggs of P. japonica can be classified as demersal. At a constant water temperature of $ 11^{citc}C$, it took 4 hours form fertilization to become four-cell stage, two days to become trochophore larvae, three days to become D-shape larvae, twenty-three days to become umbo stage, and thirty-six days to become fully grown veliger ready form settlement. A negative correlation was observed between the water temperature and the larval period of P. japonica. From fertilization to D-shape larvae, it took five days at 8$^{\circ}C$, while it was only two days to become D-shape larvae at $ 17^{citc}C$. Time required to D-shape larvae from fertilization was proportional to temperature, and the relationships were expressed as follows : To 8-cell stage, 1/t=0.0209 w-0.1167 (r=0.9967) To blastula stage, 1/t=0, 0055 w-0.0192 (r=0.9825) To trochophore stage, 1/t=0.0034 w-0.0155 (r=0.9907) To D-shape larvae stage, 1/t=0.0014 w-0.0023 (r=0.9843) (t, time in hours ; w, water temperature) Bioligical minimum temperature for egg development was calculated as 3.82$^{\circ}C$ in average.

• The Korean Journal of Malacology
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• v.17 no.2
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• pp.79-84
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• 2001

In order to obtain the basic information for seedling production of the scallop, Patinopecten yessoensis, the egg development and larva growth were investigated at different conditions such as water temperature, salinity and phytoplankton. Eggs were demersal isolated eggs, which averaged 77.3${\pm}$2.7$\mu\textrm{m}$ in diameter after spawning. The fertilized eggs developed to D-shaped larva of shell length 117.5${\pm}$3.8$\mu\textrm{m}$ after 60 hours at 15$^{\circ}C$. The range of water temperature and salinity during egg development were 10-20$^{\circ}C$ and 28-34 ppt, respectively. The time of egg development was shorter with higher water temperature. After 10 days of spawning, D-shaped larva reached 160 $\mu\textrm{m}$ in shell length, and after 25 days became full-grown larva 250 $\mu\textrm{m}$ in shell length, in which could be observed eye spots. The relative growth formula between shell length (SL) and shell height (SH) was SH = 1.0425SL-27.731 (r$^2$= 0.9749) during the entire larva period. In regard to water temperature, growth and survival rates of larvae were good at 16$^{\circ}C$. Lower growth and survival rates were observed at 12$^{\circ}C$ and 20$^{\circ}C$ than that at 16$^{\circ}C$. When larvae were fed mixed phytoplankters, such as isochrysis galbana, Pavlova lutheri and Chaetoceros calcitrans, their growth and survival rates were the highest among groups.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.267-272
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• 2012

Overcoming harsh light environment, as well as increased growth of crops even in high-quality production can play an important role when using the LED light system of photosynthetic products will be able to effectively reduce consumption. In this study, low efficiency of farm greenhouses, growing annual reduction in income due to rising operating costs and increase crop growth by inducing the proper planting environment Factory-type raise farmers' income and at the same time will contribute to the increase of Light device using LED Supplemental through photosynthesis, promote and improve product quality, plant growth regulators are considered possible for them to develop more efficient LED devices and LED Optical processing devices of Light leaf lettuce grown using normal fluorescent or incandescent bulbs grown in the results than the growth can see that the speed improvements. Usually shipped from seedling to harvest leaf lettuce from 25 to 30, whereas optical processing device be required red light (wavelength: 645nm) using a leaf of lettuce grown enough to be harvested after seven days increased the rate of growth. In addition, red light (wavelength: 645nm) and blue light (wavelength: 470nm) emitting at the same time, room, and grown for 5 days to harvest the growth rate was fast enough.

• Korean Journal of Medicinal Crop Science
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• v.11 no.1
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• pp.46-52
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• 2003

This experiment was conducted to investigate the propagation for mass production of Acanthopanax koreanum NAKAI utilized for health food and medicine material. Germination rate of A. koreanum seeds were 64% when seeds were stored at 15 for 60 days and then were treated with 50 ppm of kinetin and dormancy were broken at 5 for 60 days. Rooting rates of green-wood cuttings treated with IBA 100 ppm, NAA 50 ppm, and IAA 100 ppm were 61.7, 56.7, and 60.0%, respectively. Rooting rates of greenwood cuttings treated with Rooton in scoria + horticulture media and volcanic ash were 76.7 and 66.7%, respectively. Survival rate of seedlings planted on Aug. 10 was highest (96%) under 75% shading net while shoot growth was best under 55% shading net. Survival rate of seedlings planted on May 2 was highest (91%) 55% shading net, and shoot growth was also best 55% under shading net.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.227-234
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• 2007

The forest canopy gap has been well known as a substantial process of forest cyclic regeneration and important role in stand structure, dynamics, and biodiversity of the forest ecosystem. Based on 3,600 $5m{\times}5m$ square grids in a 9ha permanent experimental plot, the study was conducted to evaluate the regeneration pattern of woody species by developmental stage {seedlings (<1 m of height), saplingI (>1 m of height, <2 cm of DBH), and saplingII (2 cm$<200m^2$), $201-400m^2$, $400-600m^2$, $601-800m^2$, and $>800m^2$) in the mixed broadleaved-Korean pine forest. The results indicated that the regenerating trees of Populus ussuriensis occurred only in the canopy gap area, considered to be a typical gap-dependent species. The regeneration of Ulmus japonica, Ulmus laciniata, and Maackia amurensis could be generally satisfied with the gap size of $201-600m^2$, Betula costata and Prunus padus with gap size of $401-800m^2$, Picea koraiensis with gap size of $201-800m^2$, Fraxinus mandshurica and Syringa reticulata var. mandshurica with smaller than $800m^2$, respectively. Acer ukurunduense and Acer tegmentosum were likely to have no problem with the gap size to make gap regeneration. Acer mono and Tilia amurensis looked more capable of regenerating in the closed canopy disregarding the upper crown condition. The regeneration of Pinus koraiensis and Abies nephrolepis had no trouble under the canopy condition in less than $800m^2$of gap size. The density of regenerating shrubs was rather high, especially under the closed canopy, considered to be associated with great amount of regeneration production in such shade tolerant species as Lonicera maackii, Corylus mandshurica, Euonymus pauciflorus, and Philadelphus schrenkii under the closed canopy. Pearson correlation coefficient was computed to compare the similarity among non-gap area and five gap size classes by developmental stages for trees and shrubs. The similarity coefficients among closed canopy and the gap size classes were mostly significantly correlated to each other with a few exceptions.

• Journal of Biosystems Engineering
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• v.25 no.3
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• pp.213-220
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• 2000

Grafting of fruit-bearing vegetables has been widely used to increase the resistance to soil-borne diseases, to increase the tolerance to low temperature or to soil salinity, to increase the plant vigor, and to extend the duration of economic harvest time. After grafting, it is important to control the environment around grafted seedlings for the robust joining of a scion and rootstock. Usually the shading materials and plastic films are used to keep the high relative humidity and low light intensity in greenhouse or tunnel. It is quite difficult to optimally control the environment for healing and acclimation of grafted seedlings under natural light. So the farmers or growers rely on their experience for the production of grafted seedling with high quality. If artificial light is used as a lighting source for graft-taking of grafted seedlings, the light intensity and photoperiod can be easily controlled. The purpose of this study was to develop a prototype system for the graft-taking enhancement of grafted seedlings using artificial lighting and to investigate the effect of air current speed on the distribution of air temperature and relative humidity in a graft-taking enhancement system. A prototype graft-taking system was consisted by polyurethane panels, air-conditioning unit, system controller and lighting unit. Three band fluorescent lamps (FL20SEX-D/18, Kumho Electric, Inc.) were used as a lighting source. Anemometer (Climomaster 6521, KANOMAX), T-type thermocouples and humidity sensors (CHS-UPS, TDK) were used to measure the air current speed, air temperature and relative humidity in a graft-taking system. In this system, air flow acted as a driving force for the diffusion of heat and water vapor. Air current speed, air temperature and relative humidity controlled by a programmable logic controller (UP750, Yokogawa Electric Co) and an inverter (MOSCON-G3, SAMSUNG) had an even distribution. Distribution of air temperature and relative humidity in a graft-taking enhancement system was fairly affected by air current speed. Air current speed higher than 0.1m/s was required to obtain the even distribution of environmental factors in this system. At low air current speed of 0.1m/s, the evapotranspiration rate of grafted seedlings would be suppressed and thus graft-taking would be enhanced. This system could be used to investigate the effects of air temperature, relative humidity, air current speed and light intensity on the evaportranspiration rate of grafted seedlings.