• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.47-55
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• 2005

Seasonal variations of remineralization and inorganic nitrogen removal capacity were measured from Dec. 2001 to Apr. 2004 in a tidal flat located in south-western pan of Gwanghwa island, Korea by measuring the sediment oxygen demand (SOD) and denitrification. SOD was higher in muddy sediment (Dong-Mak; three year average=$683;m^{-2}d^{-1}$) than sandy sediment(Yeocha; three year average=$457;m^{-2}d^{-1}$). The SOD was high in summer and tended to be lower in winter. During the sediment incubation in Apr. 2002, production of oxygen from sediment was observed implying active benthic photosynthesis. Denitrification was also higher in muddy sediment (Dong-Mak: $5.4;m^{-2}d^{-1}$) than sandy sediment (Yeocha; $3.4;m^{-2}d^{-1}$). The denitrification rate corresponds to the carbon remineralization rate of 9.3 and $5.9\;mg-C\;m^{-2}d^{-1}$ in Dong-Mak and Yeocha, respectively. The denitrification rates were lower compared to rates observed in other coastal area $(0{\sim}200\;{\mu}mole\;m^{-2}h^{-1})$. Although Kwanghwa tidal flat sediments are replete in organic matter, remineralization activity seems to be limited by the availability of labile organic matter. The Kwangwha tidal flat may have potential to effectively remove large load of organic matter. Net remineralization rates were 196 and $132\;mg-C\;m^{-2}d^{-1}$ in Dong-Mak and Yeocha, respectively.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.77-84
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• 1984

This experiment was carried out to determine the effects of night temperature and amount of fertilization on growth and photosynthesis of red pepper plants for providing some basic imformation needed in improving the productivity of red pepper. 1. Plant height, stem length, number of flower buds, dry weight of plants and photosynthetic rate were higher in King Gun Gochu than in Dohusa, but number of leaves, number of internodes and leaf area we re higher in Dohusa compared to King Gun Gochu. 2. Plant height, number of leaves, number of flower buds, dry weight of plants, leaf area and photosynthetic rate were significantly increased by 50% increased fertilization compared to normal fertilization. 3. High night temperature($25^{\circ}C$) treatment increased plant height, stem length, number of leaves, number of internodes, number of flower buds, dry weight of plants and leaf area. 4. RGR and LAR were increased by 50% increased fertilization and high night temperature but NAR was decreased by high flower buds 5. Photosynthetic rate of King Gun Gochu was increased by 50% increased fertilization and high light intensity. 6. Number of flower buds was increased at King Gun Gochu by 50% increased fertilization and high night temperature ($25^{\circ}C$).

• Journal of Ginseng Research
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• v.32 no.4
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• pp.279-282
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• 2008

This study was conducted to compare the aerial parts growth, yield of fresh ginseng roots, quality of red ginseng roots, and photosynthesis (Fv/Fm, PSII) in leaves between non-irrigation plot and furrow irrigation plot during the ginseng growing seasons. The aerial part growth in furrow irrigation plot was higher than non-irrigation plot in all including the emergency rate, leafing rate and relatively growth rate. Root yield per 10a in irrigation plot was increased about 50% as compared with that of non-irrigation, also heaven and earth grade of red ginseng roots yield in irrigation plot was higher (40.3%) compared with that (30.6%) of non-irrigation plot in 6-years-old ginseng plant. Furrow irrigation markedly improved the ginseng quality and yield in comparison to non irrigation condition. Therefore it needs to control the soil moisture during the growing season for high yield and good qualities of ginseng roots.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.154-161
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• 2013

This study was conducted to investigate the physiological responses of Bupleurum latissimum, endangered plants by light condition. We investigated photosynthetic parameters, chlorophyll contents and chlorophyll fluorescence under different shading treatments (Shaded 50%, 70%, 90% and non-treated). Results showed that net apparent quantum yield (AQY) and chlorophyll contents were significantly increased with elevating shading level. However, light compensation point (LCP) and dark respiration ($R_d$) were shown the opposite trend. Especially, non-treated exhibited photoinhibition such as reduction of chlorophyll contents and maximum photosynthesis rate ($Pn_{max}$) also variation trend of stomatal conductance ($g_s$), and transpiration rate (E) were decreased to prevent water loss. Photosynthetic rate ($P_{Nmax}$) and photochemical efficiency (Fv/Fm) of 90% treatment showed a drastic reduction in July. This implies that photosynthetic activity will be sharply decreased with a long period of low light intensity. The 50% treatment showed relatively higher photosynthetic activity than other treated. This result suggested that growth and physiology of B. latissimum adapted to 50% of full sunlight.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.177-183
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• 2008

Sodium is known to reduce a plant growth and yields. However, the relationships between physiological response of seedling and salinity stress caused by growing media are not well understood yet. We conducted experiments to investigate change of some parameters including Na, EC, moisture content in media under different air temperature ($15^{\circ}C$, $25^{\circ}C$), and the response of fruit-vegetables such as cucumber, oriental melon on saline conditions originated from horticultural substrate. Volumetric moisture content of media at $15^{\circ}C$ was 70%, but at $25^{\circ}C$ was decreased by 45% within 22 hrs, showing below optimal matric potential, approximately. During reaction time, the increase of Na concentration was significantly greater in saline substrate than in control. The decrease rate of Na concentration according to supplying irrigation water was higher in saline substrate than in control. $CO_2$ assimilation rate and transpiration rate of Korea melon grown in low temperature were decreased with a Na/cation ratio in hydroponic solution. Water saturation deficit was also increased significantly at $15^{\circ}C$ as compare to $25^{\circ}C$. Saline stress during nursery stage induced a reduction of seedling quality, growth and cucumber yield. The results suggest that the relationship between uncontrolled Na uptake of seedling from saline substrate and meteological condition is responsible for saline stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.314-320
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• 1984

Effects of phosphorous fertilizer on the growth habit and yield of monoculm and branch types of two leading sesame varieties was investigated. The photosynthetic rate of at each growing stage was high at the flowering stage. The photosynthetic rate of monoculm sesame variety, Pungnyeon was high prior to flowering stage, while the Kwangsan variety, branch type was high after the flowering stage. The level of phosphate were most effective in increasing photosynthesis when standard level of fertilizer was applied in both varieties. Kwangsan variety showed higher photosynthetic rate per unit area, higher NAR, and CGR and higher LAR and RGR at the maximum flowering stage than the Pungnyoeon variety. Those characters attained maximum level when standard levels of phosphorous fertilizer were applied. The protein and oil content of seeds were higher in Kwangsan variety compared with Pungnyeon. However, the carbohydrate of seeds was high for Pungnyeon variety. The highest protein content was attained when standard level of fertilizer were applied. The oil content appeared to increase as the level of applied fertilizer increased. The results suggest that the vegetative growth and seed yields of sesame may be enough with present level of fertilizers. However, higher amount of phosphorous fertilizer may be required to increase the oil content of sesame seeds.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.428-434
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• 2008

The objective of this study is to investigate the effect of the level of $CO_2$ (370 and $650{\mu}mol\;mol^{-1}$) and temperature (ambient and ambient+$5^{\circ}C$) on tomato growth and fruit characteristics as affected by the application rate of N-fertilizer (68 and $204\;N\;kg\;ha^{-1}$), for the purpose of evaluating the influence of elevated $CO_2$ and temperature on tomato crop. The elevated atmospheric $CO_2$ and temperature increased the plant height and stem diameter for tomato crop, while the differences among the nitrogen(N) application rates were not significantly different. Under the elevated $CO_2$, temperature, and a higher N application rate, the biomass of aerial part increased. The fruit yield showed the same result as the biomass except for the elevated temperature. The elevated temperature made the size of fruit move toward the small, but the elevated $CO_2$ and the application of N-fertilizer were vice versa. The sugar content and pH of fruit juice were affected by nitrogen application rate, but not by the elevated $CO_2$ and temperature. These results showed that both the elevated $CO_2$ and temperature stimulated the vegetative growth of aerial parts for tomato, but each effects on the yield of fruit showed an opposite result between the elevated temperature and $CO_2$. In conclusion, the elevated $CO_2$ increased tomato yield and the ratio of large size of fruit, but the elevated temperature did not. Therefore, to secure the productivity of tomato as nowadays in future environment, it will need to develop new breeder as high temperature-tolerable tomato species or new type of cropping systems.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.159-165
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• 1993

To clarify the effects of sink demand for assimilate on leaf photosynthetic rate, tissue composition, and leaf senescence of soybean [Glycine max (L.) Merr.] J plants, pod and leaf tissues were removed at growth stage $R^3$. Plant responses were measured every 10days from 2 through 42days following treatment. Leaves of depodded plants exhibited increased starch and chlorophyll contents and specific leaf weight. Stomatal resistance was also increased and leaf photosynthetic rate was reduced. Dry weight of vegetative tissues except leaves was increased by pod removal. Leaf removal resulted in a decreased starch content of leaves from 22 to 42days after treatment and that of roots at all sampling times. Specific leaf weight was decreased while leaf photosynthetic rate was increased. Stomatal resistance and chlorophyll content were little affected. Weight per seed was decreased 3.0% by leaf removal. Except for the seed, tissue protein contents were increased by pod removal but decreased by leaf removal, however, seed protein content was not affected by either. Apparent senescence was delayed by depodding. Both apparent and functional senescence were accelerated by leaf removal.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.1
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• pp.51-59
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• 1997

Two comparative poplar clones (I-214: Populus euramericana, Peace: P koreana x P. trichocarpa) were exposed to two $CO_2$ concentrations (350 or 2,000 ${\mu}L\;L^{-1}\;CO_2)$ for 21 days. When both poplar clones were compared at growth conditions, the net photosynthetic rate $(P_N)$ in $CO_2-enriched$ (2,000 ${\mu}L\;L^{-1}\;CO_2=C_{2,000})$ plants become about $50-60\%$ higher than that of 350 ${\mu}L\;L^{-1}\;CO_2(=C_{350})$ plants on 7 days treatment. But the enhancement of $P_N$ by high $CO_2$ was not maintained throughout all the experimental period. At 21 days, there was no difference of photosynthetic rates between $C_{350}\;and\;C_{2,000}$ plants. In contrast with photosynthesis, the response of leaf conductance to the elevated $CO_2$ concentration was very different between I-214 and Peace. During all experimental period, leaf conductance $(g_s)$ of $C_{2,000}$ plants is $50\%$ lower than that of the $C_{350}$ plants for I-214, while there is no difference of $g_s$ between the plants of $C_{350}\;and\;C_{2,000}$ on for Peace. The results of gs in Peace indicate that decreased photosynthetic rate after 21 days in $C_{2,000}$ on plants for two poplar clones is possibly due to non-stomatal factors. To investigate the non-stomatal factors, starch accumulation and ribulose-1,6-bisphosphate carboxylase (RuBPCase) were measured. We found significant accumulation of starch in two poplar clones exposed to high $CO_2,$ especially starch of I-214 in $C_{2,000}$ become 3.5 times higher than in $C_{350}$ plants at 21 days. This suggests that high proportion of photosynthates was directed into starch. After 21 days, the activity of ribulose-1, 6-bisphosphate carboxylase of $C_{2,000}$ plants become decreased in $40-50\%$ compared with that of the $C_{350}$ plants. Two poplar clones show the same trend to RuBPCase declines under high $CO_2$ concentration, although the decline is more significant for I-214. The results reported here suggest that starch accumulation and decreased RuBPCase activity in $C_{2,000}$ plants can be partly ascribed to the loss of photosynthetic efficiency of high $CO_2-grown$ poplar plants.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.1
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• pp.1-9
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• 2017

Recently, it is increasing the grape farm which is converted from paddy field to orchard. These soil which are poor drainage extremely also can be damaged a lot by excessive water or flooding during heavy rain season on summer. Therefore the aim of this study was carried out to measure the changes of soil water potential and to compare the growth responses of 'Jinok' (Vitis spp.) and 'Campbell Early' (V. labruscana) grapes under three drainage systems (control, conventional drainage, and under drainage). After heavy rain, soil water potential holding times above -15 kpa applied water excessive were 352, 348 and 180 hours in control, conventional, and under drainage systems, respectively. The clay content of the under drainage system was lower than the other systems about 8-12%. The crop water stress index was lowest in the under drainage and highest in the control. Also, photosynthetic rate has showed the opposite result with crop water stress index. It was significant differences between the treatments but, the value has not shown significantly different between the varieties. In addition, leaf area and the trunk growth rate was more effective in under drainage than in the control and conventional drainage.