• Journal of Marine Life Science
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• v.7 no.2
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• pp.86-93
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• 2022

The ecotoxicity test method using Undaria pinnatifida spore is challenging to use throughout the year. Since U. pinnatifida female gametophytes can be cultured in the laboratory, they can be used for ecotoxicity testing at any time. Changes in female gametophyte survival rate and relative growth rate in U. pinnatifida exposed to various environmental conditions were analyzed. The female gametophyte of U. pinnatifida was exposed to salinity (5~40 psu), temperature (5~30℃), pH (4~10), and light intensity (0~120 μmol photon m^-2 s^-1). Based on the highest average value, the survival rate of female gametophyte was highest at a temperature of 20℃, salinity 27.5 psu, pH 8, and light intensity 30 μmol photon m^-2 s^-1. And the relative growth rate was highest at a temperature of 15℃, salinity 35 psu, pH 9, and light intensity of 60 μmol photon m^-2 s^-1. As a result of this study, the method using the optimal conditions for the survival rate and relative growth rate is expected to be a practical test method that can complement the current method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.12
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• pp.852-857
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• 2012

Recently, the indoor air pollution by microbes such as fungi and mites have become a concern as important research topic on indoor air quality. Fungal growth is significantly affected by humidity. In this study, we examined the influence of relative humidity on the surface of building materials and the water content of building materials on the fungal growth rate by measuring the mycelium length of fungi in the fungal detector placed on the surface of building materials. As a result, even if the relative humidity on the surface of building materials is identical, the more water content of building materials is, the more fungi grow faster. It was suggested that fungal growth rate depends on not only the relative humidity on the surface of building materials but also the water content of building materials.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.1-4
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• 2002

The occurrence rate of russet in 'Whangkeumbae' pear showed significant difference by years because the russet occurrence is greatly affected by the amount of rainfall. This study was conducted to analyse the relationship between rainfall and russet occurrence by artificial treatment of high humidity. Under high relative humidity condition, stomatal resistance decreased and average fruit weight was higher since the increased net photosynthesis rate accumulation accelerated fruit growth. The russet occurrence began on July 25, when the growth speed of fruit weight and fruit surface is the most fast. Russet occurrence rate was higher in high relative humidity condition because the fruit growth was accelerated. Since the fruit calcium concentration change is extreme in late July, it is assumed that the deceased calcium content is related to the occurrence of russet in 'Whangkeumbae' pear, When the high relative humidity condition is maintained after rainfall, the amount of net photosynthesis rate increase and fruit growth is accelerated. Therefore, the unbalance in the amounts of transferred photosynthesis assimilation product, water and mineral elements would be one of the reasons for the russet occurrence in 'Whangkeumbae' pear.

• Korean Journal of Organic Agriculture
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• v.11 no.1
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• pp.55-66
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• 2003

This study was carried out to investigate the effects of different plant growth media on the growth of tomato(Lycopersicum esculentum Mill.) seedlings during growth stages. The media were commercial plant growth medium 100％, earthworm cast (that was produced by vermicomposting of food waste and cattle manure) 100％, earthworm cast 50％ ＋ vermiculite 50％, earthworm cast 50％ ＋ perlite 50％, earthworm cast 40％ ＋ vermiculite 30％ + perlite 30％. Plant length(mm), number of leaves, leaf area($\textrm{cm}^2$), stem diameter(mm), plant dry mater were greatest till the 2nd week growth stages in the commercial plant growth medium plots, but those were higher in the earthworm cast than those in the other plant growth media at the later stages of this study(P<0.05). And relative growth rate of biological yield, relative growth rate of shoot and relative growth rate of root were highest in the earthworm cast till the 4th week growth stage. Therefore it can be implied that there is the possibility of potential utilization of earthworm cast, which was produced by vermicomposting of food waste and cattle manure, as vegetable growth medium.

• Journal of Korea Foresty Energy
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• v.22 no.3
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• pp.20-28
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• 2003

This study was subjected to compare seasonal changes of survival rate, relative growth rate, and chlorophyll contents of major oak tree species including Quercus acctissima, Quercus mongolica, Quercus serrata, Quercus varibilis seedlings grown in Quercus acctissima forest under different light intensities. Three light intensities were 81% of sunlight, 34% of sunlight and 21% of sunlight. In each treatment, 100 tree seedlings were planted and survival rate, growth rate, and chlorophyll contents were measured. The highest survival rate was Quercus acctissima in 73% seedlings compared with those subjected to the other tree seedlings in 45~66%. Lowest survival rate was Quercus vnriabilis seedlings in 41%. Oaks tree species of the height, the root collar diameters of the relative growth were better in the seedlings grown in 81% light intensities of full sun. But growth rates decreased rapidly in the shade treatment of 21% light intensities of full sun. Lowest chlorophyll contents(chlorophyll a, b and total) were shown at 21% light intensities of full sun, lowest light intensity treatment in this study This result is thought growth and chlorophyll contents associated with light intensity Also, Physiological characteristics has to be investigated in near future because photosynthesis and chlorophyll contents were strongly related to tree growth with long periods.

• Journal of Korea Foresty Energy
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• v.19 no.1
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• pp.20-29
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• 2000

This study was carried out to investigate the effects of shading on the growth of 1 -year-old seedlings of Cornus controversa. The height growth was highest in relative light intensities of 100% and 50%, but relative growth rate in 50% was higher than that in 100% treatment. The growth did not occur under 9% relative light intensity. The root collar diameter growth at different light intensities is similar to height growth. The leaf area was highest in 50% relative light intensity, and the leaf area under the light intensity was small compared with the control. SLA and LAI of seedlings increased with decreasing relative light intensity. The LAR and LWR of seedlings increased with decreasing light intensity, but LWR decreased at 9% relative light intensity. The dry weight of root, stem, leaf and branch, and the number of branch and leaf decreased with decreasing relative light intensity. T/R ratio was highest in 17% and 30% relative light intensity. Lateral root growth decreased with decreasing light intensity except for that in 50% light intensity.

• Korean Journal of Environmental Agriculture
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• v.24 no.1
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• pp.66-70
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• 2005

The experiment was carried out to investigate the effects of gamma radiation on the early growth performance and physiological traits of BT2 clone tea, the most promising cultivar released by Bangladesh Tea Research Institute. The fresh shoot cuttings were irradiated with seven different levels of gamma radiation such as 0, 10, 20, 30, 40, 50 and 60 Gy from Cobalt 60Co source (Dept. of PlantBreeding, Bangladesh Institute of Nuclear Agriculture). Thereafter, the irradiated shoot cuttings were planted in polythene bags and kept under natural conditions. It was observed that callusing was initiated from 8th weeks after placement of tea shoot cuttings in the polythene bags and completed by 12th weeks. The morphological growth of tea shoot cuttings were recorded under varying levels of gamma radiation and growth stages. It was observed that the number of leaves, number of primary branches, base diameter, root length and total leaf area per plant significantly increased with the progress of time and increasing levels of gamma radiation, however, the plant height showed decreasing trend with the increasing levels of gamma radiation, which could be due to the change in chromosomal structure and genetic makeup. After 56 weeks of planting, the plant height, the number of leaves and primary branches per plant, base diameter, root length and total leaf area per plant recorded were 65.70 cm, 30.67, 7.33, 1.48 cm, 23.50 cm, and 1250.67 cm2 per plant respectively under the radiation level 60 Gy, whereas the corresponding figures of the above parameters at the control treatment were 76.21 cm, 18.33, 3.67, 0.92 cm, 17.75 cm and 778.33 cm2 per plant, respectively. A significant relationship was observed among the physiological growth parameters with the increasing levels of gamma radiation. The total dry matter gain, leaf area index, absolute growth rate and relative growth rate were significantly influenced with the rising levels of gamma radiation (up to 60 Gy), whereas the net assimilation rate of individual tea plant non-significantly responded as compared to those of control treatment. Finally after 56 weeks of planting, the maximum total dry weight gain, leaf area index, absolute growth rate, relative growth rate and net assimilation rate recorded under 60 Gay radiation level were 40.25 g/plant/week, 4.25, 1.18 g/week, 0.0621g/g/week and 17.07 g/m2/week respectively.

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.163.2-163
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• 2001

No Abstract, See Full Text

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.1
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• pp.29-37
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• 2002

This study was conducted to compare ozone sensitivity among Betula sp. by measuring visible foliar injuries and growth responses. Four Betula sp.(B. costata, B. davurica, B. platyphylla var.japonica and B. ermani) grown in the greenhouse, were transplanted in the plastic pots. One-year-old seedlings of four Betula sp. exposed to relatively high ozone concentration(100 ppb) for 8 h day$^{-1}$ for 5 weeks in fumigation chamber. We measured visible injuries, leaf numbers and leaf areas at the end of experiments, and growth effects were evaluated by measuring the relative growth rate(RGR) of height and diameter and the dry weights of leaf, stem and root once a week. Four Betula species showed the significant differences for growth responses by the ozone treatment. Growths of three species, except for B. ermani, were significantly reduced by the $O_3$ exposure. B. costata with leaf senescence at the early growing stage and B. davurica indicated highest visible foliar injury rate may be the sensitive species at the 100 ppb ozone concentration. Although the growth rate of B. ermani was reduced by 100 ppb ozone exposure at the early growing stage, B. ermani may be a tolerance species that recover the growth rate with the adaptation for the high ozone concentration.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.303-309
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• 2006

The study examined the effects of $CO_2$ enrichment on growth of soybean (Glycine max). Two soybean varieties were used, Taekwang and Cheongja. The plants were grown in growth chambers with a 12-h photoperiod and a day/night temperature of $28/21^{\circ}C$ at the seedling stage and $30/23^{\circ}C$ from the flowering stage. The plants were exposed to the two elevated $CO_2$ levels of 500 and 700 ppm and the ambient level of 350 ppm. Results of the experiment showed that at the second-node trifoliate stage of the two varieties, the elevated $CO_2$ increased plant height, leaf area and dry weight. The elevated $CO_2$ also raised the photosynthetic rate of soybean as compared to the ambient level. From the beginning bloom stage to the full maturity stage of the two varieties, the elevated $CO_2$ increased plant height, leaf area, seed weight and photosynthetic rate. The stomatal conductance and transpiration rate decreased on long days relative to short days of treatment. Through the entire stages, the elevated $CO_2$ increased the water use efficiency of soybean plants because stomatal conductance and transpiration rate decreased at the elevated $CO_2$ levels relative to the ambient level.