• Journal of Korean Society of Forest Science
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• v.100 no.1
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• pp.8-13
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• 2011

This study was carried out to investigate the change of photosynthesis, leaf and fruit according to crown layers in Actinidia arguta and hybrid kiwi. Photosynthesis rate (PPFD $1,000{\mu}mol{\cdot}m^{-2}s^{-1}$) were 5.82, 7.11, $9.54{\mu}mol\;CO_2\;m^{-2}s^{-1}$ at lower, middle, and upper position, respectively in 3 layer cultivation type. The length and area of leaves collected from lower position have lager value than upper position. The fruit quality of A. arguta and hybrid kiwifruit increased with increasing crown height. A linear correlation ($R^2=0.72$, 0.89 and 0.98) was shown between fruit weight (Boeun 4, Injea 16 and HM3) and the height of crown layer(layer 1, 2, and 3). From the results, we can suppose that the tree of the upper position of crown layer in the cultivation of A. arguta and hybrid kiwifruit produce high quality fruit due to its high photosynthesis ability.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.439-446
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• 2023

Mangroves are distributed in intertidal zones of coastal environments or estuarine margins, playing a critical role in the global carbon cycle. However, understanding of the carbon cycle role of mangrove associates in the Republic of Korea is still limited. This research measured soil respiration and leaf gas exchange in three habitats of Hibiscus hamabo(Gimnyeong, Seongsan, and Wimi) and analyzed the impacts on sites and months. Soil respiration was measured once a month from June to October 2022 and leaf gas exchange was measured monthly from June to September 2022. Soil respiration in August(5.7±0.8 μmol CO₂ m^-2 s^-1) was significantly higher than that in other months (p<0.001) and soil respiration increased as air temperature increased (p<0.001). In Seongsan, net photosynthesis in July(9.0±0.9μmol m^-2 s^-1) was significantly higher than that in other months (p<0.001). Net photosynthesis increased as stomatal conductance and transpiration rate increased during the entire period(p<0.001). Furthermore, a weak positive linear relationship was observed between soil respiration and net photosynthesis (r²=0.12; p<0.01). The results indicated that soil respiration was influenced not only by air temperature and season but also by net photosynthesis. This study is expected to provide basic information on the carbon dynamics of mangrove associates.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.89-97
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• 1984

This study was carried out to investigate the effect of seasonal changes on some of the morphological and physiological characteristics, including the photosynthetic abilities and dark respiration, of young ginseng plants due to planting location under shading. The results obtained are as follows: 1. Seedlings and 2-year old plants planted in the back rows appeared to have broader leaf area, and their leaf weight greatly increased in September. Chlorophyll content was significantly reduced in September rather than in June and the plants in the back rows had more chlorophyll content than those in the front rows. 2. There was no difference in the light compensation point between the front and back rows in June, while in September the light compensation point of 2-year old ginseng leaves was much lower for plants in the back rows compared with those in the front rows. A difference in the light saturation point was not noticeable between plants in the front and back rows in June and September. But the light saturation point of 2-year old ginseng leaves at $15^{\circ}C$ was high in June, while it was high at $20^{\circ}C$ high in September. 3. Maximum photosynthetic ability was attained at $15^{\circ}C$ in June and at $20^{\circ}C$ in September. During June no significant difference in photosynthetic ability was found between plants in the front and back rows, but in September the amount of photosynthesis was significantly increased at the leaves of seedlings as well as 2-year old plants planted in the back rows. 4. The optimum temperature for maximum photosynthesis in 2-year old plants ranged from $14.0^{\circ}C$ to $14.5^{\circ}C$ in June and from $19.5^{\circ}C$ to $20.5^{\circ}C$ in September. However, the optimum temperature for maximum photosynthesis in the seedlings was from $21.2^{\circ}C$ to $21.6^{\circ}C$ in September, but a significant difference in the optimum temperature for the maximum photosynthesis in seedlings and 2-year old plants was not noticeable between the front and back rows. 5. The respiration rate was rather high in seedlings compared with 2-year old plants. During September the respiration rate in seedlings was much lower in the back rows than in the front rows. The rate of increase in the respiration of 2-year old plants was higher at September than June. The increase in respiration rate due to temperature was more significant in seedlings than 2-year old plants. 6. In September, the level of $Q_{10}$ in 2-year old plants was much lower than that found in seedlings. During June, 2-year old plants showed lower $Q_{10}$ levels at a temperature difference between $15^{\circ}C$ and $25^{\circ}C$; but in September this occurred at a temperature difference between $20^{\circ}C$ and $30^{\circ}C$.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.928-936
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• 2010

This study was conducted to select efficient foliage plants for improving indoor environment conditions through the investigation of physiological responses including photosynthetic rate according to temperature, light intensity, and $CO_2$ level. Eight popular foliage plants used in this study were $Hedera$ $helix$ L., $Cissus$ $rhombifolia$ Vahl, $Ficus$ $benjamina$ L. 'Hawaii', $Syngonium$ $podophyllum$ Schott 'Albo-Virens', $Dieffenbachia$ $sp.$ 'Marrianne', $Pachira$ $aquatica$ Aubl., $Spathiphyllum$ $wallisii$ Regel, and $Scindapsus$ $aureus$ Engler. Photosynthetic rate and transpiration rate of the plants subjected to various light intensities (0, 25, 50, 75, 100, 150, 300, and $600{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD), $CO_2$ levels (0, 50, 100, 200, 400, 700, and $1,000{\mu}molCO_2{\cdot}mol^{-1}$), and two different temperatures (16 and $22^{\circ}C$) were measured. In addition, various parameters in relation to photosynthesis were calculated from the measured data. As a result, the patterns of photosynthesis varied among 8 foliage plants according to light intensity, $CO_2$ level, and temperature. Most foliage plants except $Dieffenbachia$ had high levels of apparent quantum yield, which represents the photosynthetic rate under low light intensity (PPFD $0-100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). $Hedera$ $helix$, $Ficus$ $benjamina$, $Pachira$ $aquatica$, and $Spathiphyllum$ $wallisii$ exposed to high light intensity (PPFD $200-600{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) showed high levels of photosynthesis. $Cissus$ $rhombifolia$ and $Syngonium$ $podophyllum$ were low in $CO_2$ fixation efficiency compared to the other 6 foliage indoor plants. $Hedera$ $helix$ and $Spathiphyllum$ $wallisii$ showed high photosynthetic rate under high $CO_2$ level and vigorous photosynthesis was also observed in $Ficus$ $benjamina$ and $Pachira$ $aquatica$ grown under $22^{\circ}C$. Considering characteristics of indoor environment such as low light, high $CO_2$ level, and low relative humidity, therefore, $Hedera$ $helix$, $Spathiphyllum$ $wallisii$, $Ficus$ $benjamina$, and $Pachira$ $aquatica$ were efficient indoor foliage plants to improve indoor environmental conditions.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.540-544
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• 2001

The effect of long day treatment on the growth and flower bud differentiation of persimmon tree grown in a heated plastic house was investigated. The rate of leaf sprout was 65% in the long day treatment and 71% in natural day (control). In the long day, the shoot grew 16.7 cm longer, full bloom and harvest days were shorter, fruit weight was 16% lighter, and the sweetness and firmness of fruit were lower. The photosynthesis rate in the long day treatment was higher, showing the tendency of increasing with time. However, the rate of photosynthesis increased after 1600 hours showed higher than the control. Carbohydrate accumulation in the shoot was decreased, with higher nitrogen content and lower C/N ratio in the long day. The number of flower primordia per bud was less, and the days for differentiation was longer in the long day.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.320-330
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• 2012

This study was conducted to investigate the changes of chlorophyll contents, chlorophyll fluorescence, photosynthetic parameters, and leaf growth of Synurus deltoides under different shading treatments. S. deltoides was grown under non-treated (full sunlight) and three different shading conditions (Shaded 88~93%, 65~75%, and 45%~55%). Light compensation point ($L_{comp}$), dark respiration ($D_{resp}$), maximum photosynthesis rate ($Pn_{max}$), photo respiration rate ($P_{resp}$), carboxylation efficiency ($\Phi_{carb}$), and photochemical efficiency were decreased with increasing shading level; However, $CO_2$ compensation point ($CO_{2\;comp}$), total chlorophyll content, and specific leaf area (SLA) were shown the opposite trend. S. deltoides under 88~93% treatment showed the lowest photosynthetic activity such as maximum photosynthetic rate ($Pn_{max}$), photochemical efficiency, and $CO_2$ compensation point ($CO_{2\;comp}$). Therefore, photosynthetic activity will be sharply decreased with a long period of 8~12% of full sunlight. With the shading level decreased, carotenoid content and non-photochemical fluorescence quenching (NPQ) increased to prevent excessive light damage. This result suggested that growth and physiology of S. deltoides adapted to high light intensity through regulating its internal mechanism.

• Korean Journal of Medicinal Crop Science
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• v.25 no.6
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• pp.397-403
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• 2017

Background: This study was aimed at evaluating the growth, yield, and carbohydrate content in the whole Allium hookeri plant with shading treatment in hot summer. Methods and Results: Different shading rate, including 0 (control), 35 or 55%, was employed from the June $21^{st}$ to August $31^{st}$. Daily average air and soil temperature, which were approximately $2.5^{\circ}C$ and $3.8^{\circ}C$ lower, respectively, were observed with both 35% and 55% treatments in July and August, with no significant difference in daily maximum air temperature. Dry weights were high, approximately 40% and 48% for the shoot and 20% and 12% for the root, with the 35% and 55% treatments, respectively, 8 weeks after shading. Division number was increased by 13% and 19.8% with the 35% and 55% treatments, respectively. The mortality rates of 150 plants were 9.1%, 4.0%, and 1.3% with the 0 (control), 35% and 55% treatments, respectively. At 4 weeks after shading, the highest and lowest sucrose levels in both shoot and root were observed with the 35% and 55% treatments, respectively. At 8 weeks after shading, there was no significant difference in the sucrose content in the shoot among the treatments. Conclusions: The highest plant growth rate and yield with the 55% treatment may be related with the decrease in both air and soil temperatures, resulting in reducted leaf respiration and thus compensate net photosynthesis.

• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.827-833
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• 2018

Plasma lighting systems have been engineered to simulate sunlight. The objective of this study was to determine the effects of plasma lighting on tomato plant growth, photosynthetic characteristics, flowering rate, and physiological disorders. Tomato plants were grown in growth chambers at air temperatures of $25/23^{\circ}C$ (light/dark period), in a $16h\;day^{-1}$ light period provided by four different light sources: 1 kW and 700 W sulfur plasma lights (1 SPL and 0.7 SPL), 1 kW indium bromide plasma light, and 700 W high pressure sodium lamp (0.7 HPS) as a control. The totaldry weight and leaf area at 0.7 SPL were approximately 1.2 and 1.3 times greater, respectively, than that of 0.7 HPS at the 62 days after sowing (DAS). The maximum light assimilation rate was observed at 1 SPL at the 73 DAS. In addition, the light compensation and saturation points of the plants treated with plasma lighting were 98.5% higher compared with HPS. Those differences appeared to be related to more efficient light interception, provided by the SPL spectrum. The percentage of flowering at 0.7 SPL was 30.5%, which was higher than that at 0.7 HPS; however, there were some instances of severe blossom end rot. Results indicate that plasma lighting promotes tomato growth, flowering, and photosynthesis. Therefore, a plasma lighting system may be a valuable supplemental light source in a greenhouse or plant factory.

• Korean Journal of Plant Resources
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• v.9 no.3
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• pp.274-278
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• 1996

This study was conducted to examine the dry matter production and leaf photosynthesis under different fertilizer application in Yacon(Polymnia sonchifolia)plants. Under field conditions, dry matter production of stable mature application plot(S-1) was much larger than non-treated control plot(CTL), but bulb dry weight of 10kg nitrogen application plot per 10a (N-10) was not differentiated from CTL. The maximum photosynthetic rates increased in Yacon plants grown at S-1 while in the rates of CTL reduced under glasshouse in the same treated pot condition. The optimum temperature for the highly photosynthetic rates is about $34{\pm}3^{\circ}C$, and the rates did decrease by stomatal resistance below 28℃. The estimated light saturation point was $1200{\mu}mol{\cdot}m^{-2}s^1$. The results of this study indicate that soil conditions were highly related to dry matter production and leaf photosynthesis rate in Yacon plants.

• Korean Journal of Medicinal Crop Science
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• v.10 no.1
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• pp.1-4
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• 2002

This study was carried out to know the effect of light intensity, temperature and $CO_2$ concentration on photosynthesis and transpiration in Hovenia dulcis Thunb. Light compensation point was $2.4\;{\mu}mol\;m^{-2}\;s^{-1}$ and light saturation point was $1033\;{\mu}mol\;m^{-2}\;s^{-1}$. The optimum temperature for photosynthesis was $25^{\circ}C$ at $1000\;{\mu}mol\;m^{-2}\;s^{-1}$ light intensity. $CO_2$ compensation point was 67 vpm and $CO_2$ saturation point was 707 vpm. Transpiration rate was increased to about $2\;mmol\;m^{-2}\;s^{-1}$ with increasing of light intensity to $1750\;{\mu}mol\;m^{-2}\;s^{-1}$ and to above $4\;mmol\;m^{-2}\;s^{-1}$ with increasing of temperature from $18^{\circ}C$ to $36^{\circ}C$. however It was gradually reduced as $CO_2$ concentration increased from 21 vpm to 800 vpm.