• Journal of Microbiology
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• v.43 no.2
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• pp.191-195
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• 2005

In this study, we attempted to characterize the Synechococcus sp. pee 7942 mutant resultant from a disruption in the gene encoding UDP-glucose: tetrahydrobiopterin a-glucosyltransferase (BGluT). 2D­PAGE followed by MALDI-TOF mass spectrometry revealed that phycocyanin rod linker protein 33K was one of the proteins expressed at lower level in the BGluT mutant. BGluT mutant cells were also determined to be more sensitive to high light stress. This is because photosynthetic O$_2$ exchange rates were significantly decreased, due to the reduced number of functional PSIs relative to the wild type cells. These results suggested that, in Synechococcus sp. pee 7942, BH4-glucoside might be involved in photosynthetic photoprotection.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.48-57
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• 2009

Primary production of epiphytic and planktonic algae in a shallow reed zone of a lagoon Nishinoko was investigated. Concentrations of nutrients varied widely horizontally and locally in the lagoon. It seems that the reed zone has a heterogeneous environment. The photosynthetic rates of epiphytic and planktonic algae were 7 to 14 mg C surface stem $m^{-2}hr^{-1}$ and 12 to $46mg\;Cm^{-3}hr^{-1}$, respectively. The areal primary production of epiphytic algae was estimated as 4 to $13mg\;Cm^{-2}hr^{-1}$ from the stem density of Phragmites and the water depth at each station. The production of phytoplankton, on the other hand, was 5 to $56mg\;Cm^{-2}hr^{-1}$. The contribution of epiphytic algae to total primary production averaged 53%, although the assimilation number was much lower than that of phytoplankton. The present results indicate that the epiphytic algae are one of the significant primary producers in the reed zone.

• Journal of Forest and Environmental Science
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• v.26 no.3
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• pp.203-208
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• 2010

This study was conducted to investigate the net photosynthetic rate, stomatal transpiration, stomatal conductance, water use efficience, and intercellular $CO_2$ concentration in Allium ochotense leaves and Allium microdictyon leaves. The light compensation point was 4.2 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in Allium ochotense leaves and 5.2 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in Allium microdictyon leaves. The lght saturation point was approximately 800 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in between Allium ochotense leaves and Allium microdictyon leaves. The phtosynthetic rate of Allium ochotense leaves was higer than that of Allium microdictyon leaves. On the other hand, at more than $30^{\circ}C$, it appeared that the values of net photosynthetic rates of Allium microdictyon leaves were higher than that of Allium ochotense leaves. These results suggest that growth of those Allium ochotense plants are appropriate for relatively cool temperature site compared to Allium microdictyon plants.

• Journal of Ginseng Research
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• v.23 no.1 s.53
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• pp.1-7
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• 1999

Photosynthetic rates and leaf bleaching were measured under light of far-red, red, orange, green, blue and white in order to clarify the effect of light qualities on photosynthesis in Panax species, P. ginseng and P. quinquefolium. Photosynthetic rate of P. ginseng and P. quinquifolium showed higher in the order under the light of red > orange > blue > white > green. Degree of leaf bleaching in P. quinquifolium showed severer in the order under the light of far-red > red > white > blue > orange > green. These suggest that shading material with blue or orange color is good for ginseng growth. As for the effect of temperature, the photosynthesis was increased with increasing temperature untill $25^{\circ}C$ and thereafter decreased. Therefore, it was clarified that the optimum temperature for photosynthesis of P. ginseng and P. quinquefolium was $25^{\circ}C$. And the dark respiration rate of ginseng leaf also increased with increasing air temperature. Especially, the dark respiration rate increased by $80\%$ for P. ginseng and by $73\%$ for P.quinquefolium at above $30^{\circ}C$ as compared with $25^{\circ}C$. In general, the photosynthesis rate was higher in P. quinquifolium than in P. ginseng and ranged from 3.54 to 4.04 mg $(CO_2{\cdot}dm^{-2}{\cdot}hr^{-1})$ for P. quinquefolium and from 2.08 to 2.59 mg$(CO_2{\cdot}dm^{-2}{\cdot}hr^{-1})$ for P. ginseng.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.291-296
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• 2017

This study was conducted to evaluate the influence of early defoliation on photosynthesis and carbohydrate reserves when the source leaves of 'Fuji'/M9 apple (Malus domestica Borkh.) trees were removed during the growing period. Bud regrowth rates of 80%, 50% defoliation and non-defoliation treatments were significantly different 82.7%, 45.9% and 2.1% respectively at 30 days after treatment. In all treatments, sucrose and starch concentrations in remaining leaves decreased non-significantly during the 14-day period. No significant changes were observed for total soluble carbohydrates in non-defoliation and 50% defoliation. However, in 80% defoliated treatments, concentrations of sorbitol and total soluble carbohydrates in remaining leaves declined steadily during the 14-day period. It is thought that high sink strength increases the requirements of carbohydrate from remaining leaves more than non-defoliated. The concentrations of starch in the roots tend to decrease non-significantly as percentage of defoliation increased. Photosynthesis of remaining leaves was monitored during the 14-day period after partial defoliation treatments. Net photosynthetic rates (Pn) and stomatal conductance were significantly enhanced in the 80% defoliation. The observed photosynthetic enhancement following partial defoliation may have been due to the enhancement of osmotic potential in leaves. These results were estimated that increasing of photosynthetic rate in the partial defoliation is due to the sink carbohydrate requirements for the current year's secondary growth of buds.

• Journal of Korean Society of Forest Science
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• v.81 no.1
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• pp.11-20
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• 1992

This study was conducted to compare chlorophyll contents, photosynthetic abilities, and ribulose-diphosphate (RuDP) carboxylase activities of Quercus acutissima seedlings grown with and without cotyledons under different light intensities and different nutrient levels. The results obtained in this study were as follows : 1. Chlorophyll contents were not significantly different among the light intensities except for 25% of full sunlight at the last harvest time. 2. RuDP carboxylase activity increased with increasing light intensity. 3. Photosynthetic abilities of seedlings grown under full and 75% of sunlight were significantly higher than that under 25% of full sunlight. 4. RuDP carboxylase activity was more related with chlorophyll a contents(r=0.792) than chlorophyll b contents(r=0.314). 5. RuDP carboxylase activities of the seedlings received at 1 or 2% addition rates of nutrients under 75% of full sunlight were higher than that at 0.5% addition rates.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.4
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• pp.353-359
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• 1988

Variations in photosynthetic capacities of leaves differing in thickness were explained on the basis of relationships between gas exchange and internal leaf structure. The relative importance of gas diffusion and of biochemical processes as limiting for leaf photosynthesis was also determined. Mesophyll cell surface was considered to be the limiting internal site for gas diffusion. and cell volume to be indicative of the sink capacity for CO$_2$ fixation. Increases in cell surface area were assumed to reduce proportionately mesophyll resistance to the liquid phase diffusion of CO$_2$. Increased cell volume was thought to account for a proportional increase in reaction rates for carboxylation, oxygenation. and dark respiration. This assumption was tested using chamber-grown Glycine max (L.) Merr. cv. Amsoy plants. Plants were grown under 200, 400, and 600 ${\mu}$mol photons m$\^$-2/ s$\^$-1/ of PAR to induce development of various leaf thickness. Photosynthetic CO$_2$ uptake rates were measured on the 3rd and 4th trifoliolate leaves under 1000 ${\mu}$mol photons m$\^$-2/ s$\^$-1/ of PAR and at the air temperature of 28 C. A pseudo -mechanistic photosynthesis model was modified to accommodate the concept of cell surface area as well as both cell volume and surface area. Both versions were used to simulate leaf photosynthesis. Computations based on volume and surface area showed slightly better agreement with experimental data than did those based on the surface area only. This implies that any single factor, whether it is photosynthetic model utilized in this study was suitable for relating leaf thickness to leaf productivity.

• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.922-928
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• 2010

There is a little information on the effect of calcium cloride ($CaCl_2$) which is used as deicing salt in Korea on the physiological responses of the street trees. Prunus sargentii is one of the most widespread tree species of street vegetation in Korea. In this study, the effect of $CaCl_2$ on photosynthetic apparatus such as chlorophyll fluorescence image and light response curve of P. sargentii in relation to their leaf and root collar growth responses were investigated. To study the effect of $CaCl_2$ treatment in the early spring, we irrigated twice in rhizosphere of P. sargentii (3-year-old) planted plastic pots with solution of 0.5%, 1.0%, 3.0% $CaCl_2$ concentration before leaf expansion. Results after treatments, total chlorophyll contents and the chlorophyll a/b, photosynthetic rate, quantum yield, dark respiration decreased with increasing $CaCl_2$ concentration. On the contrary, light compensation point increased with increasing $CaCl_2$ concentration. Through the linear regressions of correlation of photosynthetic rate with photosynthetic parameters (quantum yield, dark respiration and light compensation point), we found a significant relationship (p<0.05) between photosynthetic rate and quantum yield and light compensation point except dark respiration. Calcium cloride ($CaCl_2$) induced inhibition of photochemical efficiency ($F_v/F_M$) and non-photochemical quenching (NPQ) were found in treatments of $CaCl_2$, and these reduction rates between control and CaCl2 treatments were drastically showed at 80 days. We suggest that physiological activities are limited from treatment of $CaCl_2$. These reductions of photosynthetic apparatus ability caused eventually the reduction of leaf and diameter at root collar growth.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.3
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• pp.237-245
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• 1999

Rates of photosynthesis and respiration of Laminaria japonica sporophytes cultivated on the southeastern coast of Korea were monthly measured in situ and under constant temperature and nitrogen concentration in laboratory from February to July 1996 in order to understand the seasonal photosynthetic performance of this alga. P-I (the relationship between photosynthsis and irradiance) parameters measured in situ varied seasonally. Photosynthetic capacity ($P_{max}$) reached its maximum in March (6.64 mg $O_2{\cdot}gdw^{-1}{\cdot}h^{-1}$) and gradually decreased thereafter. Photosynthetic efficiency (${\alpha}$), which ranged from 0.026 to 0.106, generally showed a similar pattern with the $P_{max}$, curve. Correlation between respiration and $P_{max}$, was not significant (Spearman's rank correlation, p>0.05); respiration rate, which varied between 0.25 and 0.83 mg $O_2{\cdot}gdw^{-1}{\cdot}h^{-1}$, showed no gradual decline from March. $P_{max}$ in situ significantly correlated with the relative growth rate of frond weight (Spearman's rank correlation, p<0.01) and this result means that the amount of accumulated materials in body increased with the increment of $P_{max}$. Compared $P_{max}$, in situ with that in the laboratory. The lower $P_{max}$ in February was probably caused by the effect of lower seawater temperature at this time. The decrease in $P_{max}$ after March, however, was primarily attributable to the thickness of blade as the plants got old. Comparison of P-I parameters measured for different size groups in April, explained the negative relationship between $P_{max}$ and frond thickness.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.452-460
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• 2000

This study was to investigate the growth characteristics, physiological adaptation of Pinus densiflora(Japanese Red Pine) seedlings at the artificial canopy gap in the Quercus acutissima plantation and to analyze its natural regeneration mechanism. Photosynthetic and transpiration rates were analyzed by different levels of photosynthetically active radiation and by seedling growth. Comparing to seedlings at the open area, those at the canopy gap showed more growth in height than in diameter with different levels of light quality and low light intensity, and the increase rate of dry weight was higher in the aboveground than in the underground, maintaining relatively high T/R rate. The C/F(the ratio of non-photosynthetic organs to photosynthetic organs in dry weight) of the aboveground at the canopy gap was higher than that at the open area by 0.1~0.2, while light saturation and light compensation points at the canopy gap were lower than that at the open area by $300{\mu}mol\;m^{-2}s^{-1}$ and 40%, respectively. The seedlings appeared to have shade tolerance to a certain extent at the young growth stage despite Pinus densiflora is typically classified shade-intolerant species. With light intensity lower than $400{\sim}450{\mu}mol\;m^{-2}s^{-1}$, photosynthetic rate and water use efficiency relatively increased by effective use of light energy.