• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.239-239
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• 2017

The enhancement of leaf photosynthetic capacity can have the potential to improve the seed yield of soybean. Key targets for the increase of leaf photosynthetic capacity remains unclear in soybean. Peking, Chinese local variety, has been the useful material for soybean breeding since it shows various resistances against biotic and abiotic stress. Sakoda et al., 2017 reported that Peking had the higher capacity of leaf photosynthesis than Enrei, Japanese elite cultivar. They identified the genetic factors related to high photosynthetic capacity of Peking. The objective of this study is to elucidate the physiological basis underlying high photosynthetic capacity of Peking. Peking and Enrei were cultivated at the experimental field of the Graduate School of Agriculture, Kyoto University, Kyoto, Japan. The sowing date was July 4, 2016. Gas exchange parameters were evaluated at the uppermost fully expanded leaves on 43, 49, and 59 days after planting (DAP) with a portable gas exchange system, LI-6400. The leaf hydraulic conductance, $K_{leaf}$, was determined based on the water potential and transpiration rate of the uppermost fully expanded leaves on 60 DAP. The morphological traits related to leaf photosynthesis were analyzed at the same leaves with the gas exchange measurements. The light-saturated $CO_2$ assimilation rate ($A_{sat}$) of Peking was significantly higher than that of Enrei at 43 and 59 DAP while the stomatal conductance ($g_s$) of Peking was significantly higher at all the measurements (p < 0.05). It suggested that high $A_{sat}$ was mainly attributed to high $g_s$ in Peking. $g_s$ is reported to be affected by the morphological traits and water status inside the leaf, represented by $K_{leaf}$, in crop plants. The tendency of the variation of the stomatal density between two cultivars was not consistent throughout the measurements. On the other hand, $K_{leaf}$ of Peking was 59.0% higher than that of Enrei on 60 DAP. These results imply that high $g_s$ might be attributed to high $K_{leaf}$ in Peking. Further research is needed to reveal the mechanism to archive high $g_s$ on the basis of water physiology in Peking. The knowledge combining the genetic and physiological basis underlying high photosynthetic capacity of Peking can be useful to improve the biomass productivity of soybean.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.134-138
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• 1997

The objective of this study was to examine the effect of phosphorus deficiency on nitrogen fixation and photosynthesis of nitrogen fixing soybean plant under $CO_2$ enrichment condition. The soybean plants(Glycine max [L.] Merr.) inoculated with Bradyrhizobium japonicum MN 110 were grown with P-stressed(0.05 mM-P) and control(1 mM-P) treatment under control$(400\;{\mu}l/L\;CO_2)$ and enrichment$(800\;{\mu}l/L\;CO_2)$ enviromental condition in the phytotron equipped with high density lamp$(1000\;{\mu}Em^{-2}S^{-1})$ and $28/22^{\circ}C$ temperature cycle for 35 days after transplanting(DAT). At 35 DAT, phosphorus deficiency decreased total dry mass by 64% in $CO_2$ enrichment condition, and 51% in control $CO_2$ condition. Total leaf area was reduced significantly by phosphorus deficiency in control and enriched $CO_2$ condition but specific leaf weight was increased by P deficiency. Phosphorus deficiency significantly reduced photosynthetic rate(carbon exchange rate) and internal $CO_2$ concentration in leaf in both $CO_2$ treatments, but the degree of stress was more severe under $CO_2$ enrichment condition than under control $CO_2$ environmental condition. In phosphorus sufficient plants, $CO_2$ enrichment increased nodule fresh weight and total nitrogenase activity(acetylene reduction) of nodule by 30% and 41% respectively, but specific nitrogenase activity of nodule and nodule fresh weight was not affected by $CO_2$ enrichment in phosphorus deficient plant at 35 DAT. Total nitrogen concentrations in stem, root and nodule tissue were significantly higher in phosphorus sufficient plant grown under $CO_2$ enrichment, but nitrogen concentration in leaf was reduced by 30% under $CO_2$ enrichment. These results indicate that increasing $CO_2$ concentration does not affect plant growth under phosphorus deficient condition and phosphorus stress might inhibit carbohydrate utilization in whole plant and that $CO_2$ enrichment could not increase nodule formation and functioning under phosphorus deficient conditions and phosphorus has more important roles in nodule growth and functioning under $CO_2$ enrichment environments than under ambient condition.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.139-146
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• 2004

Kenaf (Hibiscus cannabinus L.), an annual plant of the family Malvaceae, is considered to be the most promising for alternative plants with potential use as a non-wood fiber source. The objectives of this study were to select the optimum seeding date and adaptable cultivar among newly introduced kenaf cultivars (Everglades-41, Tainung-2 and Chingpi-3) in Jeju island, and to clarify the photosynthetic characteristics of those cultivars. Among the three cultivars, the fresh shoot weight per unit area of Chingpi-3 at harvest season showed highest through all seeding dates, that of while Everglades-41 was the lowest. The difference of shoot yield at harvest mainly due to seedling stand rate and plant number per unit area among the cultivars. The Chingpi-3 showed the highest shoot fresh weight in the seeding date of May 11 and decreased trend in the late seeding dates. Net photosynthesis rate was higher on Everglades-41 with entire type leaf than other two cultivars with palmate type leaf. The activity of ribulose-1,5-bisphosphate carboxylase/foxygenase (rubisco) estimated from the A-Ci curve showed highest in Chingpi-3 among three cultivars. These results suggest that Chingpi-3 might be adaptable cultivar with seeding date of around May 10 for kenaf production in Jeiu island.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.3
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• pp.163-168
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• 2021

The growth experiment under shading condition has been performed to understand the eco-physiological responses of crops to light in terms of photosynthesis. There are two types of shading: overall shading and partial shading. In this study, the chlorophyll fluorescence of soybean was observed under the overall shading of the box made by polyresin and the partial shading at agrivoltaic system. The overall shading condition during vegetative growth induced lower SPAD and Electron transport rate (ETR). These lower values recovered after removal of shading box. However, the Non-photochemical fluorescence quenching (NPQ) became lower under overall shading and higher under partial shading. Such increase in NPQ limited crop photosynthesis even though the ETR was almost same to the control without shading treatment. Under the condition of partial shading, the values of SP AD and ETR for soybean did not change. However, the NPQ was higher than control condition. This suggests that the crop photosynthesis under both types of shading would be decreased by different eco-physiological processes which are the lower ETR in overall shading and the higher NP Q in partial shading despite the reduced light under shading conditions.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.101-109
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• 2008

The content of chlorophyll a, b have generally increased for Fraxinus rhynchophylla and Fraxinus mandshuricain the order of month of June B>C and >D. Therefore we suppose the photosynthesis rate will increase if the moisture level is high and in regardless of the growth stage.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.288-293
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• 1996

This study was investigated to obtain basic information for the development of irrigation plans in upland cultivation of Wasabi. Changes of stomatal conductivity and photosynthetic rate of Wasabi, and of the soil water potential during withholding watering were analysed. The stomatal conductivity of Wasabi at $1000{\mu}Em^{-2}s^{-1}$ light intensity was $70mmolem^{-2}s^{-1}$, which was about 49% lower than that of Chinese cabbage, $138mmolem^{-2}s^{-1}$. The temporal changes of light intensity during the daytime did not influence the stomatal conductivity. The soil water potential that decreased stomatal conductivity in Wasabi was about - 50kPa at 10 AM, and about - 30kPa at 3 PM. The photosynthetic rate of Wasabi at$1000{\mu}Em^{-2}s^{-1}$ light intensity was $7.6mgdm^{-2}hr^{-1}$, which was about 50% lower than that of Chinese cabbage, $15.3mgdm^{-2}hr^{-1}$. The duration required for a stable photosynthetic rate was longer in Wasabi than in Chinese cabbage. The soil water potential that decreased photosynthetic rate in Wasabi was about - 50kPa at 10 AM, and about - 30kPa at 3 PM. The stomatal conductivity and photosynthetic rate showed significant positive correlation at various soil water potential. The results indicated that irrigation in wasabi could be done during the daytime when the soil water potential is above - 30kPa, which does not decrease stomatal conductivity and photosynthesis in Wasabi.

• Journal of Ginseng Research
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• v.27 no.4
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• pp.202-206
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• 2003

This study was conducted to compare the growth status of aerial parts, photosynthesis and microclimate between fixing light transmittance (Control) and changing light transmittance (C.L.T.) during ginseng growing seasons. Control showed 8％ light transmittance rate during growing seasons. But C.L.T. showed 18％ light transmittance rate during early (April-June) and late growth stage (September-October) and 6％ light transmittance rate middle growth stage(July-August). Air temperature, leaking water rate and soil water content of C.L.T. was higher than those of control during early and late growth stage. But Air temperature, leaking water rate and soil water content of C.L.T was lower than those of control during middle growth stage C.L.T. exhibited superiority in survival ratio, stem diameter, stem length, L.A.I. and stem angle compared to control. Chlorophyll content of C.L.T. was lower than that of control but S.L.W., stomatal opening and photosynthetic rates of C.L.T. was higher than those of control. Also Alternaria blight disease and defoliation of C.L.T. was lower than those of control.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.305-313
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• 2011

Fertilization is essential to seedling production in nursery culture, but excessive fertilization can contaminate surface and ground water around the nursery. The objective of this study was to find optimal fertilization practice of container seedling production for reducing soil and water contamination around the nursery without compromising seedling quality. This study was conducted to investigate growth performance, photosynthesis, chlorophyll fluorescence, and chlorophyll contents of Liriodendron tulipifera growing under three different fertilization treatments (Constant rate, Three-stage rate, and Exponential rate fertilization). Root collar diameter, height, and biomass of L. tulipifera were the highest at Constant treatment. Like growth performance, seedling quality index (SQI) were higher at Constant than at other treatments, but not significantly different among treatments. L. tulipifera showed good photosynthetic capacity at all treatments. Photochemical efficiency and chlorophyll contents were significantly lower at Exponential than at other treatments. Therefore, Exponential fertilization which is 50% fertilizer of other treatments would maximize seedling growth and minimize nutrient loss.

• Journal of the Korean Society of Tobacco Science
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• v.17 no.1
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• pp.20-26
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• 1995

This study was carried out to obtain the basic data which include the change of the photosynthetic rate and protein content according to growth stage in the process of senescence of tobacco plant The photosynthetic rate was the maximum with 26.31$\mu$mol.CO2/m2.sec and stomatal resistance was the minimum with 0.2552cm/sec at 15th days after leaf emergence. However, after 50 days the photosynthesis was very little occurred. During leaf developments the number of chloroplast was increased and reached at the maximum at 25th days after emergence of leaf, thereafter, it was decreased gradually. The content of protein increased continuously and showed the highest value at 15th days after leaf emergence. The degradation rate of soluble protein was more rapid than that of insoluble protein at early stage of senescence. The range of decrement in the insoluble protein was low at late stage of senescence. The content of Rubisco, the key enzyme of photoamthesis, corresponded to about 50% of soluble protein and reached to the maximum at 150 days after leaf emergence. As the senescence progressed, the content of large subunit(UV) of Rubisco showed a tendency to decrease more rapidly than that of small subunit(SSU). The total amount of amino acids was the highest at 15th days after leaf emergence.

• Journal of the Korean Institute of Landscape Architecture
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• v.21 no.1
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• pp.139-148
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• 1993

The present experiments have been conducted to find out the plant's growth environments habitate, mode of life, characteristic of photosynthesis, habit of growth and propagation. The results of this study are as follows: 1. Sambucus williamsii var. Coreana distributes around all sides of native site without having any relation to altitude, inclination and direction. 2. In the native site, Robinia pseudo - acacia and its neighboring species were Prunus yedoensis, Acer pseudo-sieboldianum, Lindera obtusiloba and Staphylea bumalda. From 21 to 41 types of species were located in the vegetation of the quadrat area. 3. According to the variation of leaf temperature with the result of the change of net photosynthetic rate, the optimum temperature for growth is $25^{\circ}C$. 4. The rooted rate of vegetative propagation was the highest at 100ppm IBA plot and the lowest at 200ppm BA plot. 5. The rooted rates of Sambucus williamsii var. coreana in perlite 50% bed, vermiculite bed and peatmoss 50%+sand 50% bed are higher than others.