• Journal of Korean Society of Forest Science
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• v.96 no.4
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• pp.462-469
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• 2007

The present study was conducted to investigate photosynthetic responses and growth performances of Liriodendron tulipifera, Betula costata, and Carpinus cordata seedlings growing under four different light regimes (full sun and 54~65%, 26~37%, 8~13% of full sun). L. tulipifera and B. costata showed the highest photosynthesis rate of 13.59, $16.29{\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$, respectively, at full sun. And photosynthesis ability and growth performances were decreased as increasing shade level in the above two species. C. cordata showed the highest photosynthesis rate of $9.47{\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ at 26~37% of full sun. Also, growth performances of height, root collar diameter, and biomass showed the results similar to photosynthetic responses presented in C. cordata.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.340-345
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• 2006

A potato (Solanum tuberosum L. cv. Superior) cultivar was grown in aeroponic cultivation system to investigate the effect of root zone cooling in summer. Based on their nutrient uptake, growth responses, and tuberization, the possibilities for potato seed production were determined. Although shoot growth and early tuberization increased in the conventional non-cooling root zone system (root zone temperature of $25\pm2^{\circ}C$), stolen growth, photosynthesis, transpiration rate and number of tubers produced were higher in the cooling root zone system ($20\pm2^{\circ}C$) than in the non-cooling system. Increasing root zone temperature above $25^{\circ}C$ stimulated absorption of K more than T-N, P, Ca, Fe and Mn. On the other hand, root zone temperatures in the range of $20^{\circ}C$ to $25^{\circ}C$ did not affect Mg contents. The lower uptake and supply to leaves of T-N, Fe and Mn at the high root zone temperature promoted early tuberization and advanced haulm senescence. The results stress the importance of keeping root zone temperature to as low as below 20, particularly in summer under temperate Bone.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.1
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• pp.110-115
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• 2004

This experiment was conducted to investigate the effect of light intensities on the growth responses, carbohydrate contents and the characteristics of leaf gas exchange in Miscanthus sinensis and Pennisetum purpurascens. The plant height and leaf length were increased to about 30% in the sun. However, those were reduced severely in the shade, and leaf necrosis was also observed. The representative growth index and the dry weight of 2 species were 50% higher than shade and the rate was reduced according to the decrease of light intensities. Total carbohydrate contents showed very similar changes to that of dry weight. However, any notable influences were observed at above the light intensities of 250~500${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in the half shade. The size of spikes and the earliest spiking appeared in the sun and the spike color was decolorized as decreased in light intensities, irrespective of species. Photosynthetic rate of 2 species was 2 times higher in the sun than those in the shade, and it showed the typical photoresponses of sun plant. Stomatal conductances and intercelluar $CO_2$ concetration showed similar changes to that of photosynthetic rate. On the contrary, vapor pressure deficit was increased more in the shade than in the sun.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.4
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• pp.298-302
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• 2019

Acidic soil significantly reduces crop productivity mainly due to aluminum (Al) toxicity. Alfalfa (Medicago sativa L.) roots were exposed to aluminum stress (Al₃⁺) in calcium chloride (CaCl₂) solution (pH4.5) and root growth, physiological and antioxidant enzyme responses were investigated. The root growth (length) was significantly inhibited after 48 h of aluminum stress imposition. Histochemical staining with hematoxylin indicated significant accumulation of aluminum in Al stress-treated root tissues. Histochemical assay were also performed to detect superoxide anion, hydrogen peroxide and lipid peroxidation, which were found to be more in root tissues treated with higher aluminum concentrations. The enzymatic activity of CAT, POD and GR in root tissues was slightly increased after Al stress treatment. The result suggests that Al stress alters root growth in alfalfa and induces reactive oxygen species (ROS) production, and demonstrates that antioxidant enzymes involved in detoxification of Al-mediated oxidative stress.

• Journal of fish pathology
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• v.23 no.3
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• pp.343-355
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• 2010

This study was conducted to investigate the dietary effects of lactic acid bacteria (LAB) supplementation on growth, hematological and immune responses of grey mullet, Mugil cephalus. Three replicate groups of grey mullet (body length, $62.8{\pm}1.04\;mm$ ; body weight, $3.2{\pm}0.13\;mg$) were fed the experimental diets with 0 (control), 1, 2.5 and 5,0 % of LAB for 3 months. Total body length growth rate was increased in 2.5 % supplementation group compared to control (P<0.05). No differences were observed in hematological parameters (hematocrit, hemoglobin, RBCs) and serum chemistry (calcium, magnesium, total protein, glucose, GOT and GPT). The antioxidant activity of grey mullet fed the 5.0 % LAB diets was significantly higher than that of other groups (P<0.05). Both intracellular superoxide anion production and lysozyme activity of kidney were higher in the 2.5 % LAB diet than in the control (P<0.05).

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.341-351
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• 2022

The physiological characteristics, growth, and yield of each regional rice variety ('Odaebyeo', 'Saechucheong', 'Ilmibyeo') were investigated depending on the impact of changes in temperature and CO₂ concentration. Experiments were conducted with a control group, which reflected atmospheric CO₂ concentration and temperature, and treatment groups, in which the CO₂ concentration and temperature were increased by 250 ppm and 2.0℃ from those in the control group. The results showed that the increase in CO₂ concentration and temperature reduced the growth and yield of the rice 'Odaebyeo', but did not substantially change the productivity of the 'Saechucheong' and 'Ilmibyeo'. The increase in CO₂ concentration and temperature increased stomatal conductance and rate of transpiration of the 'Odaebyeo' variety, thereby decreasing its water use efficiency (WUE). In contrast, the increase in CO₂ concentration and temperature increased the photosynthetic rate and WUE of the 'Saechucheong' and 'Ilmibyeo' varieties. The gradual change in climate is considered to directly affect growth and development of rice and diversely affect the productivity of each variety. Therefore, it is necessary to implement technological development, select regionally optimal rice varieties, develop new rice varieties, as well as conduct long-term monitoring of each rice variety for climate adaptation to counter global warming.

• Korean Journal of Organic Agriculture
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• v.14 no.4
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• pp.385-397
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• 2006

This study was conducted to establish the environment-friendly cropping system of soybean in paddy field with different soil textures. When the soybean was cultivated in paddy fields, growth responses of testing cultivars varied depending on soil texture and cultivation method. Growth responses of soybean in sandy loam tended to be better than those in clay, however the effect of high ridged cultivation was distinguished in clay loam. Especially, formation of rhizome nodule was significantly different depending on soils ; more numerous rhizome nodules were formed in sandy loam compared to that in clay. Plant heights of Taekwangkong and Eunhakong were highest in clay and sandy loam, respectively, while the number of pods and branches of Eunhakong were most in both soils. In clay paddy field, growth responses of Eunhakong were best among the testing cultivars, however high ridged cultivation was more appropriate to the cultivar compared to level row cultivation regardless of soils. Taekwangkong showed the highest leaf area indexes during whole growth stages. Leaf development of Daewonkong was suppressed in clay at early growth stage, while it significantly increased as growth stages progressed. Most retard leaf development was observed in early maturity cultivar, Hwaseongputkong, since it seemed to be seriously damaged by excess-moisture injury in both soils. Comparing the dry weight of top plants and roots, plant growth was more affected by soil texture than cultivation methods at early vegetative growth stage, via verses at R2 or R5 stages. In yield characters and yields at R8 maturity stage, pods number of Eunhakong was significantly higher than those of Daewonkong and Taekwangkong estimating to 107 and 124 in clay and sandy loam, respectively. The ratio of ripened seeds was highest in sandy loam in combination with high ridged cultivation, while the lowest in clay with level row. The yields of Deawonkong and Eunhakong were higher compared to other testing cultivars ranged from $l82{\sim}286kg/ha$ depending on soils and cultivation methods. In results, growth responses and yields of testing cultivars tended to be higher in sandy loam in combination with high ridge compared to clay with level row.

• Journal of Aquaculture
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• v.16 no.1
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• pp.31-36
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• 2003

Two experiments were conducted for the physiological and growth responses of yearling sea bass, Lateolabrax japonicus (total length 24.4$\pm$1.5 cm, body weight 125.4$\pm$25.4 g) by the manipulation of salinity. To study the physiological responses of the sea bass by acute salinity change, we changed water salinity from 30 ppt into 2 ppt in rearing tank through 1 hour or 6 hour. To access the effect of salinity in the growth of sea bass, we also examined the growth of the sea bass in 2, 10, 20 and 30 ppt for 180 days. After salinity change, all yearlings appeared some stress response and ions changes in blood. The yearlings showed a slow recovery by an acute salinity exchange, but a fast recovery by slow salinity exchange. In the study about the influence of salinity in growth, although the food intake of yearlings in 20 ppt was significantly higher than the yearling in the other salinities, feed efficiency was higher in 10 ppt than the other salinities. However, the food intake and the feed efficiency in 2 ppt were significantly lower than in other groups. The growth of yearlings was significantly faster in 20 ppt than in the other salinities, but the growth showed significantly slower in 2 ppt than in the other salinities.

• Journal of Korea Foresty Energy
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• v.19 no.1
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• pp.1-6
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• 2000

This study was carried out to investigate the growth responses of Pinus densiflora seedlings to enhanced UV-B environment for 16 weeks in the field condition. The seedlings were treated with one of three levels of UV-B dosages - ambient UV-B, ambient + 3.2, and ambient + 5.2 KJ m$^{-2}$day$^{-1}$ and the irradiation was performed at the stage before the germination, the fully expanded cotyledon, and the primary needles grown more than 0.8cm in length of the seedlings, respectively. Enhanced UV-B irradiation reduced the height and the root collar diameter growth, and dry mass production of the seedling, and T/R ratio was increased by the UV-B treatment. Difference in seedling growth was observed by difference in time of the UV-B treatment. Among the seedlings which were treated with ambient - 3.2 KJ m$^{-2}$day$^{-1}$, height and root collar diameter growth was relatively high in the seedling received the UV-B treatment at the stage before the germination. The lowest dry mass production was observed in the seedlings received the UV-B at stage of cotyledon both in two levels of enhanced UV-B treatment. Chlorophyll concentration was reduced by enhanced UV-B irradiation, and chlorophyll a/b ratio was increased by the UV-B treatment.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.306-306
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• 2017

Screening for drought and salinity tolerance was undertaken for selected Philippine upland rice landraces during germinative and seedling stages to identify varieties which can potentially be grown in marginally dry and saline soils. While increasing PEG and NaCl concentrations caused obvious signs of injury to all rice genotypes, considerable varietal differences were noted in the nature of responses providing evidence that these genotypes possess broad intraspecific genetic variations for drought and salt tolerance. Inconsistent responses of these varieties during both growth stages highlight complexities involved in stress responses and underscore the futility of utilizing a single stage in the rice plant's life cycle for physiological screening. Notwithstanding these perplexing responses, G_Katiil and Ml-Pilit Tapul were observed to thrive relatively well despite increased salt and drought stress during early growth stages and may therefore possess genes needed in crop improvement efforts for drought and salinity tolerance. While these results do not reflect the entire spectrum of adaptive expression to drought and salinity stress during the life cycle of the upland rice plant, they nonetheless provide an easy, reliable and reproducible method for preliminary identification of drought and salt tolerant rice varieties.