• ALGAE
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• 제20권3호
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• pp.233-238
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• 2005

The photosynthetic parameters of dark- adapted minimum fluorescence (Fo) and maximum quantum yield of charge separation in PSII (Fv/Fm) were measured in transverse sections of eight species of marine Phaeophyceae (species of Laminariales, Fucales, Desmarestiales, Chordariales) using pulse amplified modulation (PAM) fluorometry. Within each transverse section fluorescence was measured in three regions corresponding to outer cortical and meristoderm cells, inner cortical cells and innermost medullary cells. Minimum fluorescence declined from 19-74% (mean of 39%) from outermost to innermost cells. Maximum quantum yield varied from 0.51-0.59 in outermost cell layers and this was reduced to 0.23-0.40 in innermost cell layers, with an average reduction of 50%. Despite the reduction Fo in medullary cells (inner), medullas of all species showed maximum quantum yields consistent with a photosynthetic role in carbon fixation. These results show that medullary cells of complex brown algae have more than a role in structure, storage or transport, and may also provide an important role in carbon fixation.

• Journal of Ginseng Research
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• 제34권4호
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• pp.274-281
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• 2010

This experiment was conducted to examine ginseng lines resistant and susceptible to high-temperature injury and to investigate characteristics of the selected lines: leaf burning phenomenon, chlorophyll content, quantum yield, and maximum light interception rate. The leaf burning phenomenon incidence rates of the resistant lines Yunpoong, high-temperature injury resistance (HTIR)1, HTIR2, and HTIR3 were low: 5.8%, 3.6%, 4.0%, and 1.9%, respectively. Resistance of the susceptible lines Chunpoong, high-temperature injury susceptible (HTIS)1, and HTIS2 was high: 58.5%, 23.2%, and 21.7%, respectively. The chlorophyll content (SPAD value) of the resistant lines Yunpoong, HTIR1, HTIR2, and HTIR3, which were exposed to high temperatures and intense light, remained as high at 24.8, 27.9, 24.9, and 30.6, respectively, but that of the susceptible lines Chunpoong, HTIS1, and HTIS2 was low at 21.0, 21.1, and 20.1, respectively. During the summer season, the quantum yield of the resistant lines (Yunpoong, HTIR1, HTIR2, and HTIR3) changed little, but that of the susceptible lines (Chunpoong, HTIS1, and HTIS2) changed dramatically. The maximum light interception rate (Fm/Fv value) for the resistant lines (Yunpoong, HTIR1, HTIR2, and HTIR3) was as high as 0.848, 0.794, 0.805, and 0.813, respectively, while that of the susceptible lines (Chunpoong, HTIS1, and HTIS2) was 0.678, 0.642, and 0.717, respectively. Based on these results, the high-temperature injury-resistant lines seemed to be less susceptible to high light, even at high temperatures. Future studies on red ginseng quality and its active ingredients in resistant ginseng lines and field experimentation will be conducted to verify the potential of the resistant lines.

• The Plant Pathology Journal
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• 제34권3호
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• pp.236-240
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• 2018

Crop yield is critically related to the physiological responses and disease resistance of the crop, which could be strongly affected by high temperature conditions. We observed the changes in the growth of barley under higher than ambient air-temperature conditions using a temperature gradient field chamber (TGFC) during winter and spring. Before the stem extension stage of barley growth, Cladosporium sp. spontaneously appeared in the TGFC. The severity of disease became serious under warmer temperature conditions. Further, the stomata closed as the severity of the disease increased; however, stomatal conductance at the initial stage of disease was higher than that of the normal leaves. This was likely due to the Iwanov effect, which explains that stressed plants rapidly and transiently open their stomata before longer-term closure. In this study, we tested three optical methods: soil-plant analysis development (SPAD) chlorophyll index, photochemical reflectance index (PRI), and maximum quantum yield (Fv/Fm). These rapid evaluation methods have not been used in studies focusing on disease stress, although some studies have used these methods to monitor other stresses. These three indicative parameters revealed that diseased barley exhibited lower values of these parameters than normal, and with the increase in disease severity, these values declined further. Our results will be useful in efficient monitoring and evaluation of crop diseases under future warming conditions.

• 생명과학회지
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• 제32권10호
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• pp.743-748
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• 2022

부추는 아시아를 포함한 전세계적으로 분포하는 초본이다. 한국에서 부추는 양념용 채소와 국수용 고명에 사용된다. 질소비료, 인산비료, 칼리비료와 수분 스트레스가 부추(Allium tuberosum Rotter) 잎에 미치는 영향에 대해 조사하였다. 엽록소 a 함량은 10 mg/l 질소 비료에서 0.386였고, 50 mg/l에서는 0.584였다. 엽록소 a, b, 전체 엽록소량은 대조군에 비해 유의한 차이를 나타내었다(p<0.05). 엽록소 a, b, 전체 엽록소에 대한 피어슨 상관계수(Pearson's r)는 각각 0.940, 0.966, 0.971였다. 잎의 엽록소 a, b, 전체 엽록소는 인산비료인 경우 40 mg/l가 50 mg/l 시비보다 높았다. 인산 비료인 경우 10 mg/l에서 전체 엽록소량은 0.312였고 50 mg/l 일 때 0.589였다. 엽록소 효율과 습도와의 관계를 산출하였다. 광합성 효율의 척도로 기저 수준의 형광산율(Fo), 최대 형광산율(Fm), 전자소멸 상태(Fv), 최대 PSII 광계비율(Fv/Fm)의 기울기는 각각 -0.931, 0.972, 972, 0.950였다. 질소, 인산, 칼륨 비료와 가뭄스트레스는 부추의 엽록소함량과 효율성에 영향을 주었다.

• 생물환경조절학회지
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• 제27권3호
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• pp.231-238
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• 2018

본 연구는 대목과 접수의 결합 단계에서 나타나는 스트레스를 오이접목묘의 엽록소형광반응, 엽록소함량, 활착 및 생장 특성 측면에서 분석하고자 수행되었다. 이를 위해서 활착실 내의 광합성유효광양자속은 25, 50, 100, $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$의 4수준으로 설정되었고, 기온, 상대습도 및 LED 램프의 광주기는 각각 $25^{\circ}C$, 90%, $16h{\cdot}d^{-1}$이었다. 본 연구에서 얻어진 결과를 요약하면 다음과 같다. 대목의 최대양자수율은 0.84-0.85로서 광량에 따른 분명한 차이가 나타나지 않았다. 한편, 접수의 최대양자수율은 접목 후 2일째에 0.81-0.82로 낮게 나타났으나, 3일째부터 광량이 높을수록 접수의 최대양자수율이 증가하였다. 활착 후 4일째에 측정된 접수의 엽록소함량은 광량이 증가할수록 높게 나타났다. 오이접목묘의 활착율은 광량이 $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ 이하일 때 90-95% 정도로 높게 나타났으나, $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$의 처리구에서는 80% 정도로 저하되었다. 광주기에 따라 다르나, 오이접목묘의 활착에 적합한 한계 광량은 플러그 트레이 표면에 조사된 광량을 기준으로 $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ 정도이다. 본 연구에서 처리된 광강도 하에서 활착된 오이접목묘의 발근에 최소 2일이 소요되었고, 이 기간에 접수의 최대양자수율은 최저치로 나타났다. 활착 단계에서 조사되는 광량에 따라 대목과 접수의 변이형광과 최대양자수율이 다르게 나타났다. 그러므로 접목묘의 활착 단계에서 나타나는 스트레스를 줄이면서 대목의 발근을 촉진하고, 접수의 최대 양자수율이 급격하게 저하되는 것을 방지하려면 광 및 습도 등의 물리적 환경이 정확하게 제어되어야 한다. 향후 접목묘의 활착 단계에서 대목의 발근, 통도조직의 결합 상태, 수분의 이동에 따른 엽록소함량 변화를 정량적으로 구명할 필요가 있다.

• 한국토양비료학회지
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• 제48권6호
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• pp.705-711
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• 2015

Management of soil water and fertilization is known to primarily affect physiological properties and yield in plant. The effect of soil water potential and nitrogen application on characteristics of photosynthesis and chlorophyll fluorescence in Schisandra chinensis Baillon was investigated on a sandy loam soil. Net photosyntheis rate and transpiration rate increased as a photon flux density and was highest at -50kPa of soil water potential. Light compensation point ($1.5{\mu}molm^{-1}s^{-1}$) and dark respiration ($0.13{\mu}molCO_2m^{-1}s^{-1}$) was lowest at -50 kPa but maximum photosynthesis rate ($13.10{\mu}molCO_2m^{-1}s^{-1}$) and net apparent quantum yield ($0.083{\mu}molCO_2m^{-1}s^{-1}$) was highest at -50 kPa. As results of chlorophyll fluorescence by OJIP analysis, maximum quantum yield (Fv/Fm) of photosystem II (PSII) and PIabs was higher in treatments of -50 kPa and -60 kPa respectively, which reflects the relative reduction state of PSII. But the relative activities per reaction center such as ABS/RC and DIo/RC were low with decreasing soil water potential. Net photosyntheis rate and transpiration rate were highest at treatment of soil testing 1.0 times ($92kgha^{-1}$). Application of nitrogen resulted in high Fv/Fm, $PI_{abs}$ and low ABS/RC, DIo/RC. This result implies that -50 kPa of soil water potential and nitrogen fertilizer may improve the efficiency of photosynthesis through controlling a photosystem in Schisandra chinensis Baillon.

• 생물환경조절학회지
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• 제28권4호
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• pp.461-470
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• 2019

본 연구는 육안판단이 아닌 엽록소형광 이미지 측정기법을 이용하여 비파괴적으로 수박접목묘 플러그트레이 단일 셀에 대해 건조스트레스를 정량화하고자 수행되었다. 접목 후 6일차 수박접목묘를 3일동안 균일한 관수관리 하에서 재배한 후 건조스트레스를 부여하였다. 이후 플러그트레이 단일 셀 형태의 수분함량센서를 이용하여 D1(53.0%, 충분한 수분상태)단계부터 D9(15.7%, 극심한 건조스트레스)단계까지 9개 그룹으로 분류하고 엽록소 형광을 측정하였다. 또한 건조스트레스에 영향을 받은 묘(D5-D9)에 재관수하여 육안판단으로 확인되지 않은 광합성 및 생육 회복 수준을 측정하였다. 3개의 건조스트레스 단계의 엽록소형광 곡선 형태는 건조스트레스 조기 탐지에 대해 다른 양상을 보였다. 총 16개의 엽록소 형광 지수는 건조스트레스에 노출되면서 지속적으로 감소하였으며, 육안으로 판단 가능한 D5(32.1%)단계에서 크게 감소하였다. 형광감소율(Rfd_Lss)는 초기 건조스트레스 수준(D5-D6)에서 명확하게 감소하기 시작하였으며, 최대 광화학효율(Fv/Fm)은 극심한 건조스트레스 수준(D7-D9)에서 크게 감소하였다. 따라서, Rfd_Lss 및 Fv/Fm 지수를 건조스트레스의 초기 및 이후 단계에서 생육 및 광합성 회복 평가를 위한 지표로 선정하였다. 개별 엽록소형광 지수의 수치값 차이와 엽록소형광 이미지를 통해 건조스트레스 수준이 직관적으로 확인되었다. 이러한 결과는 Rfd_Lss와 Fv/Fm은 각각 초기 및 극심한 건조스트레스를 탐지하지 위한 엽록소형광 지수로 활용될 수 있으며, Fv/Fm은 재관수시 회복 평가를 위한 최적의 엽록소형광 지수로 판단된다.

• 한국환경농학회지
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• 제39권2호
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• pp.138-141
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• 2020

BACKGROUND: Fresh weight is one of the major quality measurement factors in determining the quality of fresh fruits. A practical method has been developed for rapid and non-destructive measurement using the Chlorophyll Fluorescence Image (CFI) technique to estimate changes in fresh weight of post-harvest products. METHODS AND RESULTS: Kiwifruit (Actinidia deliciosa) was used and measured for the fresh weight and CFI under different temperature conditions at 0, 10, and 20℃, from 0 to 21 days after storage (DAS). We observed the fresh weight of kiwifruit and measured the surface image for determining F_v/F_m value in terms of maximum quantum yield on each day. To estimate freshness of kiwifruit we applied linear regression between the measured fruit weights and F_v/F_m values. Results showed that fruit weights were reduced by 4% at 0℃, 6% at 10℃, and 14% at 20℃ for 21 days, respectively. And also, the value of Fv/Fm was shown as decreasing trend at all temperature conditions, especially at 20 ℃. Fv/Fm values showed highly significant correlation (R²>0.9) with fresh weight of kiwifruit at all different storage temperatures. CONCLUSION: Thus, CFI technique can be useful to estimate the fresh weight of kiwifruit.

• Journal of Photoscience
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• 제5권4호
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• pp.169-174
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• 1998

Photosynthetic responses to dehydration were examined by the simulataneous measurement of O2 evolution and chlorophyll (Chl) fluorescence in green pepper leaves. Dehydration was induced by immersing the plant roots directly in the Hoagland solution containing varying concentration (2-30%) of polyethylene glycol(PEG-6000) . Water potential of the leaf was decreased time-and concentation -dependently by PEG-treatment. The decrease in water potential of leaf was correlated with the decrease in both the maximal photosynthesis (Pmax) and quantum yield of O2 evolution, but Pmax dropped more rapidly than quantum yield at all water deficit conditions tested. However, Chl fluorescence parameters were not affected much. Dehydration did not change the initial fluorescence (Fo) and maximum photochemical efficiency(Fv/Fm) of photosystem(PS) II. Both the photochemical quenching (qP) and non-photochemical quenching(NPQ) were not changed by dehydration under low PFR(50 $\mu$mols m-2s-1 ). In contrast, under high PFR(270$\mu$mols m-2s-1)qP was slightly decreased while NPQ was greatly increased. The fast induction kinetics of Chl fluroecence showed no change in Chl fluorescence pattern by dehydration at high PFR (640 $\mu$mols m-2s-1 ), but exhibited a significant drop in peak level(Fp)at low PRFR (70$\mu$mols m-2s-1 ). PS I oxidation and reduction kinetics revealed normal reduction but delayed oxidation to P-700+, suggesting no lesionin electron flow from PSII to PSI , but impaired electron transport to NADP+,These results suggest that water stress caused by PEG-treatment results in the reduction of photosynthesis, promarily due to the reducted electron trasport from PSI to NADP+ or hampered subsequent steps involving Calvin Cycle.

• Journal of Plant Biology
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• 제36권2호
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• pp.133-140
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• 1993

The photosynthetic activities in relation to oxygen evolution rates, quantum yield, CO2 uptake rates and room temperature chlorophyll fluorescence were investigated in cotyledons of cucumber seedlings exposed to low temperature (at 4$^{\circ}C$) for 24 h. Light-chilling caused more inhibition on light-saturated maximum oxygen evolution rates, quantum yield, and CO2 uptake rates than dark-chilling did in the cucumber plant. Light-chilling induced more marked increase in Fo and decrease in (Fv)m/Fm than dark-chilling did in the room temperature chlorophyll induction kinetics. The above results affected by chilling in the light are considered to be associated with the partial damage of the reaction center of PS II and the decreased photosynthetic activities. There occurred a large decrease in qQ with little change in qNP in the light-chilling plant. When light- and dark-chilled plants were recovered at room temperature for 24 h and their chlorophyll fluorescences were induced with light doubling technique, light-chilled plants showed more smaller magnitude and rate of fluorescence relaxation than dark-chilled plants. These suggest that light-chilling might cause some alterations in transthylakoid pH formation, and that photosynthetic apparatus of cucumber cotyledons is more susceptible to light-chilling. In the fast fluorescence induction kinetics, FR was decreased by 60% in the light-chilled plants with reference to $25^{\circ}C$ light-grown plants, while the dark-chilled plants showed a decreased rate of only 20% with reference to $25^{\circ}C$ dark-treated plants for 24 h, indicating that cucumber seedling is very sensitive to chilling stress. So, it is certain that chilling injury to the photosynthetic apparatus is strongly dependent on the presence of light in cucumber seedlings.