• 한국농림기상학회지
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• 제18권4호
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• pp.357-365
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• 2016

본 연구는 대기 중 $CO_2$ 농도의 증가가 배추(B. campestris subsp. napus var. pekinensis)의 광합성과 생리적 특성에 미치는 영향을 조사하여 미래의 대기중 $CO_2$ 농도 증가로 인한 고랭지 배추의 생산성을 예측해 보고자 수행하였다. 대기 $CO_2$ 농도를 달리하여 배추를 5주 동안 재배하였을 때, 지상부 생체량, 엽수, 엽면적, 엽장, 엽폭은 모두 대기 $CO_2$ 농도 조건($400{\mu}mol{\cdot}mol^{-1}$)에서 재배된 배추에서보다 고농도의 $CO_2$ 조건($800{\mu}mol{\cdot}mol^{-1}$)에서 재배된 배추에서 더 높게 나타났다. 그리고 증산률(E)이 다소 낮았지만, $CO_2$ 고정률(A), 기공전도도($g_s$)와 수분이용효율(WUE)도 고농도의 $CO_2$에서 높았다. 최대광합성률($A_{max}$)은 대조구인 대기 중 $CO_2$ 농도에서 보다 고농도의 $CO_2$ 조건에서 2.2배 더 높았다. 광보상점($Q_{comp}$)은 대조구에서보다 고농도의 $CO_2$ 조건에서 다소 낮았다. 순양자수율(${\varphi}$)은 고농도의 $CO_2$ 조건에서 재배된 배추에서 높았다. 그러나, $CO_2$반응곡선으로부터 얻은 광호흡률($R_p$), 최대카르복실화속도($V_{cmax}$), $CO_2$ 보상점(CCP), 최대전자전달률($J_{max}$), 탄소고정효율(ACE) 등은 $CO_2$ 농도에 따라서 차이가 없거나 있더라도 미미하였다. 그리고, 광계II의 최대 광화학적 효율($F_v/F_m$)과 잠재적 광합성능($F_v/F_o$)이 $CO_2$ 농도에 따라 유의한 차이를 보이지 않아 고농도 $CO_2$ 조건이 고랭지 재배시 배추의 생육에 스트레스로 작용하지 않는 것으로 보인다. 배추의 광합성을 위한 최적 온도는 고농도 $CO_2$에서 $2^{\circ}C$ 정도 더 높았으며, 최적온도 이상의 조건에서는 대기 $CO_2$와 고농도 $CO_2$에서 모두 $CO_2$ 고정률은 감소하고 암호흡은 증가하는 양상을 보였다. 이상의 결과로부터 미래의 대기 중 $CO_2$ 증가는 고랭지 재배시 배추의 생육에 있어서 스트레스 요인으로 작용하지는 않으며 수광량의 증가가 생산성을 향상시킬 것으로 보인다.

• Journal of Biosystems Engineering
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• 제37권5호
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• pp.314-318
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• 2012

Purpose: This study was conducted to develop a measurement system for determining photosynthetic photon flux (PPF) distribution and illumination efficiency of LED lamps. Methods: The system was composed of a linear moving sensor part (LMSP), a rotating part to turn the LMSP, a body assembly to support the rotating part, and a motor controller. The average PPF of the LED lamp with natural cooling and water cooling was evaluated using the measurement system. Results: The PPF of LED lamp with water cooling was 3.1-31.7% greater than that with natural cooling. Based on the measured value, PPF on the horizontal surface was predicted. Illumination efficiency of the LED lamp was slightly increased with water cooling by 3.4%, compared with natural cooling. A simulation program using MATLAB was developed to analyze the effects of the vertical distance from lighting sources to growing bed, lamp spacing, and number of LED lamps, on the PPF distribution on the horizontal surface. The uniformity of the PPF distribution of the LED lamps was fairly improved with 15 cm spacing, as compared to the 5 cm spacing. By simulation, PPF of $217.0{\pm}27.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ was obtained at the vertical distance of 40 cm from six LED lamps with 12 cm spacing. This simulated PPF was compared to the measured one of $225.9{\pm}25.6{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. After continuous lighting of 346 days, the relative PPF of LED lamps with water cooling and natural cooling was decreased by 6.6% and 22.8%, respectively. Conclusions: From these results, it was concluded that the measurement system developed in this study was useful for determining PPF and illumination efficiency of artificial lighting sources including LED lamp.

• 한국광과학회:학술대회논문집
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• 한국광과학회 1997년도 학술대회지
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• pp.41-41
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• 1997

• 생물환경조절학회지
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• 제19권4호
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• pp.203-209
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• 2010

연구는 관엽식물 4종을 배지종류, 광도 및 이산화탄소 농도를 달리하여 식물의 광합성 반응을 조사하고, 그 결과에 기초하여 실내환경 조절에 효율적인 식물을 선정하고자 실시하였다. 식물재료로는 싱고니움, 디펜바키아, 쉐프렐라 홍콩, 드라세나를 사용하였으며, 성분과 성질이 다른 두 배지(peatmoss, hydroball)에 각각 재배하였다. 광도는 PPFD 0, 30, 50, 80, 100, 200, 400, $600{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$의 수준으로 조절하고, 이산화탄소 농도는 0, 50, 100, 200, 400, 700, 1000, $1500{\mu}mol{CO_2}{\cdot}mol^{-1}$의 수준으로 처리하였다. 광도 및 엽육내 $CO_2$ 농도변화에 따른 관엽식물의 광합성 반응을 조사한 결과, 약광에서의 광합성 능력을 나타내는 순양자수율은 쉐프렐라 홍콩과 디펜바키아에서 높게 나타났으며, 두 실내식물은 고농도의 이산화탄소 환경에서도 다른 두 식물에 비해 높은 광합성율을 기록했다. 드라세나 와네키는 두 조건 모두에서 가장 낮은 광합성 효율을 보였다. 두 배지 처리에 따라서는 각각의 관엽식물에서 엇갈린 광합성 반응이 관찰되었다. 쉐프렐라 홍콩은 피트모스 배지에서 광과 이산화탄소 증가에 따라 하이드로볼 배지에 비해 높은 광합성 속도를 보였지만, 디펜바키아는 그와는 정반대로 하이드로볼 배지에서 더욱 높은 광합성율을 기록했다. 싱고니움의 경우는 광처리에 의해서는 피트모스 배지에서 높은 광합성율을 보였지만 이산화탄소 처리에서는 배지간 차이가 없었다. 가장 낮은 광합성 효율을 보인 드라세나 와네키는 광에 의한 배지간 차이가 없었으며, 이산화탄소 증가시에는 피트모스에서 다소 높은 광합성율을 보였다. 따라서 실험한 4가지 관엽식물 중 광합성 효율이 가장 높았던 쉐프렐라 홍콩이나 하이드로볼 배지에서 높은 효율을 보인 디펜바키아가 실내 공기정화 및 실내 환경조절에 적합할 것으로 판단된다.

• 생물환경조절학회지
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• 제21권2호
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• pp.153-161
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• 2012

피음처리에 의한 고려엉겅퀴와 누룩치의 광합성 및 생장특성을 조사하기 위하여, 차광막을 이용하여 전광처리구(0%), 약피음처리구(45~55%), 중간피음처리구(65~75%), 강피음처리구(88~92%) 설치하고 엽록소함량, 엽록소 형광반응, 광합성 반응 등을 조사하였다. 고려엉겅퀴와 누룩치 모두 피음처리 수준에 따라 엽록소 함량과 엽록소형광반응, 순양자효율 등이 증가하여 빛의 흡수와 광합성 반응에 대한 효율을 높이는 내음성 적응 반응을 나타냈으며, 엽면적 SLA 역시 증가하여 부족한 광환경에서 수광량을 늘리기 위해 엽면적은 늘어나고, 엽두께는 얇아지는 형태적인 변화가 나타났다. 특히 전광처리구에서 총 엽록소 함량, 엽록소 형광반응, 순양자효율, 기공전도도 및 기공증산속도가 비교적 낮았으며, 이는 강한 광으로 광저해 현상이 일어나 광합성 능력이 저하되는 것으로 볼 수 있다. 고려엉겅퀴의 강피음 처리구는 엽록소 함량도 높으며, 엽면적이 늘어나고 엽두께는 얇아져 광을 수집하기 위한 형태적인 변화도 나타나고 있으나 광선요구도보다 적은 광 환경에서 계속 생장함으로서 엽육내 $CO_2$를 효율적으로 소비하지 못하고, 수분이용효율 역시 감소되어 광합성 능력을 점점 상실해 가는 것으로 생각된다. 또한 고려엉겅퀴는 약광처리구(전광의 45~55%)에서최대광합성속도와 순양자효율이 가장 높고, 기공개폐 반응과 광화학반응 효율이 비교적 높았으며, 누룩치는 처리구간의 차이는 크지 않지만, 중간피음처리구에서 최대광합성속도, 순양자수율, 기공개폐반응 및광화학효율이 가장 높은 것으로 나타났다. 따라서 적절한 피음처리를 통해 건전한 생육을 유도하기 위해서는 고려엉겅퀴의 경우 전광을 약 45~55% 차단하고, 누룩치는 약 65~75% 차단시킨 광환경이 효과적이라 생각된다.

• 환경생물
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• 제26권1호
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• pp.15-21
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• 2008

Ionizing radiation causes many alterations in photosynthetic machineries. However, there is no information about effects of ionizing radiation on the development of photosynthetic machineries in plants. We investigated the greening of etiolated mung bean seedlings after gamma-irradiation of 50 to 300 Gy. The irradiation inhibited seedling growth with great dependence on the radiation dose. In particular, growth of stems was more affected than that of hypocotyls. Irradiated leaves showed inhibition in growth, aberration in morphology, and yellowing in color depending on the radiation dose. Contents of photosynthetic pigments such as chlorophylls and carotenoids were significantly decreased in the irradiated leaves. The apparent electron transport rate for photosynthesis, ETR, was similarly changed depending on the radiation dose. However, the maximal photochemical efficiency of Photosystem II (PSII), Fv/Fm, was little affected by the irradiation. Moreover, the 50-Gy seedlings maintained the control level of light saturating for photosynthesis and showed slightly higher Fv/Fm values in spite of significant decreases in the photosynthetic pigment content and ETR. These results suggest that the inhibition of the overall photosynthetic capacity couldn’t be causally relatqaed with the repression in the initial development of irradiated seedlings and that the overall photosynthetic machineries can develop and work to some extent as a concerted system for photosynthesis even after exposure to acute doses of ionizing radiation.

• Journal of Crop Science and Biotechnology
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• 제11권1호
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• pp.75-82
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• 2008

Functional stay-green is a beneficial trait that may increase grain yield through the sustained photosynthetic competence during monocarpic senescence in cereal crops. The temporal changes of photosynthesis and related characteristics throughout the grain filling period of a stay-green japonica rice "SNU-SG1" was compared in growth chamber conditions with three high-yielding cultivars(HYVs) and their $F_1$ hybrids with SNU-SG1. SNU-SG1 exhibited a typical characteristic of functional stay-green in terms of chlorophyll degradation and photosynthetic competence during grain filling. According to the photosynthesis-light response curve measured at 10 and 35 d after heading for the flag leaf, SNU-SG1 exhibited higher initial light conversion efficiency and thus higher gross photosynthetic rate at light saturation compared to HYVs. Light saturation point was not different among genotypes, ranging from 1000 to 1500 ${\mu}mol$ photon $m^{-2}s^{-1}$. Net photosynthetic rate at light saturation($P_{max}$) of the upper four leaves in SNU-SG1 was much higher and sustained longer throughout grain-filling than HYVs and $F_1$ hybrids. The sustained high photosynthetic competence of SNU-SG1 during grain filling was ascribed to the longer maintenance of high mesophyll conductance that resulted from not only high chlorophyll content and its delayed degradation but also the slow degeneration of photosystem II(PS II) as judged by chlorophyll fluorescence($F_v/F_m$) of flag leaves. $F_1$ hybrids showed slow degeneration of photosystem II similar to the male parent SNU-SG1 while chlorophyll degradation pattern close to female parents, thus exhibiting a little higher $P_{max}$ than female parents. These results suggest that SNU-SG1 has a typical functional stay-green trait that can be utilized for increasing rice yield potential through the improved dry matter production during grain filling.

• 한국약용작물학회지
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• 제26권2호
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• pp.181-187
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• 2018

Background: This study aimed to investigate out the influence of drought stress on the physiological responses of Dendropanax morbifera seedlings. Methods and Results: Drought stress was induced by discontinuing water supply for 30 days. Under drought stress, photosynthetic activity was significantly reduced with decreasing soil water content (SWC), as revealed by the parameters such as Fv/Fm, maximum photosynthetic rate ($P_{N\;max}$), stomatal conductance ($g_s$), stomatal transpiration rate (E), and intercellular $CO_2$ concentration (Ci). However, water use efficiency (WUE) was increased by 2.5 times because of the decrease in $g_s$ to reduce transpiration. Particularly, E and $g_s$ were remarkably decreased when water was withheld for 21 days at 6.2% of SWC. Dendropanax morbifera leaves showed osmotic adjustment of -0.30 MPa at full turgor and -0.13 MPa at zero turgor. In contrast, the maximum bulk modulus of elasticity ($E_{max}$) did not change significantly. Thus, Dendropanax morbifera seedlings could tolerate drought stress via osmotic adjustment. Conclusions: Drought avoidance mechanisms of D. morbifera involve reduction in water loss from plants, through the control of stomatal transpiration, and reduction in cellular osmotic potential. Notably photosynthetic activity was remarkably reduced, to approximately 6% of the SWC.

• 한국대기환경학회지
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• 제14권6호
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• pp.537-544
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• 1998

We selected Spathiyhyllum patinii and Pachira aqkatica, since the former has high O3 absorption while the latter low absorption, and analyzed physiological factors such as diffusive coefficient, transpiration rate, photosynthetic rate, and CO2 absorption rate, which affected O3 absorption capacity There was significant relationship between gas absorption capacity and the other factors; photosynthetic rate, diffusive resistance, stomatal resistance and CO2 absorption rate. Therefore model formula for estimation of O3 absorption rate in plant was formulated by making use of these factors. There was difference for the estimation of O3 absorption rate according to plant species. In case of Spathiphyllum patinii, photosynthetic rate is an optimal factor for estimation of O3 absorption capacity. On the other hand, stomatal resistance and diffusive resistance are optimal factors of Pachira aquatica among various physiological ones. And we knew that CO2 absorption rate is a potential factor to evaluate gas absorption capacity regardless of plant species. But considering efficiency and practicality, diffusive resistance was the most effective factor for the estimation of O3 gas absorption.

• ALGAE
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• 제24권2호
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• pp.93-104
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• 2009

Imaging-PAM fluorometry was used to assess the chlorophyll a fluorescence parameter ${\Phi}_{PSII}$ (effective quantum yield) in Frcus vesiculosus. F. disttchus. ssp. distichus and AscophyIIum nodosum. The objective was to show variadon in fluorescence yield associated with age and frond organ, and to illustrate the spatial scales at which photosynthetic parameters vary on fucoid thalli. In addition, our species represented taxa in different but related genera, species with different ecoloeies (rock pool and non rock pool species), morphologies (with and without air bladders) and longevities (several to 20 or more years). A further objective was to determine the extent to which photosynthetic parameters reflected these differences- Effective quantum yield declined substantially with age in F. vesiculosus and F. distichus ssp. distichus, whereas ${\Phi}_{PSII}$ in A. nodosum was maximal after three years. In A. nodosum ${\Phi}_{PSII}$ was still high in branch segments at least seven years old. Older branches of A. nodosum showed relatively higher and more homogeneous photosynthetic capacity relative to Fucus species. Surfaces of air bladders in A. nodosum and F. vesicu- losus had ${\Phi}_{PSII}$ that was not significantly different from the highest rates, achieved in these species. The heterogene- ity of photosynthetic efficiency is consistent with morphological and developmental differences among the species and their ecology. in particular the longevity of A. nodosum fronds.