• 한국환경과학회지
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• 제22권11호
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• pp.1403-1413
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• 2013

The effects of cadmium ions ($Cd^{2+}$) on the Chl a fluorescence of Ricciocarpos natans were investigated in order to determine whether Chl fluorescence can be used as a biomarker to estimate the physiological responses of plants to cadmium stress. In all plants treated with $Cd^{2+}$, the image of Fv/Fm, which represents the maximum photochemical efficiency of PSII, changed as the $Cd^{2+}$ concentration increased, when treated for 48 h or more. Changes of ${\Phi}_{PSII}$ and $Q_P$ images were recognized even at 10 ${\mu}M$ $Cd^{2+}$. The Chl a O-J-I-P fluorescence transient was also affected even at 10 ${\mu}M$ $Cd^{2+}$. The fluorescence yield decreased considerably in steps J, I and P in plants treated with $Cd^{2+}$, although a typical polyphasic rise was observed in non-treated plants. The Chl fluorescence parameters, Fm, Fv/Fo, Sm, SFIabs, PIabs and ETo/CS, decreased as the $Cd^{2+}$ concentration increased, while the Mo and Kn parameters increased. Peroxidase activity decreased significantly and catalase activity increased as the $Cd^{2+}$ concentration increased. Because of its sensitivity to $Cd^{2+}$ Ricciocarpos natans is useful in experiments investigating the responses of plants to cadmium exposure. Several parameters (Fm, Fv/Fo, Sm, SFIabs, PIabs, ETo/CS, Mo and Kn) can be applied to determine quantitatively the physiological states of plants under cadmium stress.

• Journal of Plant Biology
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• 제37권2호
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• pp.231-236
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• 1994

분리한 시금치 엽록체에 $Cd^{2+}$을 처리하였을 때 광계 I에 비해서 광계 II의 활성이 낮은 농도의 $Cd^{2+}$에 의해 억제되었다. 그러므로 $Cd^{2+}$에 의해 1차적으로 광계 II 활성이 저해되었다는 것을 알 수 있다. 광계 II의 전자공여체인 diphenylcarbazide를 첨가했을 때 대조구에 비해 활성이 크게 증가하였다. $Cd^{2+}$ 처리시 $Mn^{2+}과\;Ca^{2+}을$ 외부에서 첨가했을 때 광계 II 활성은 회복되었지만 회복되는 정도가 15%로 낮았다. $50\;\mu\textrm{M}\;Cd^{2+}$ 처리구에서 광계 II 활성은 크게 감소하였으나 Fv/Fm는 미소하게 감소하였으며 $100\;\mu\textrm{M}\;Cd^{2+}$ 처리구에서 Fv/Fm는 크게 감소하였다. 광계 I활성은 $Cd^{2+}$의 처리 농도가 증가함에 따라 감소하였으나 세척하였을 경우 0.2 mM의 $Cd^{2+}$ 처리구에서 대조구보다 활성이 증가하였으며 농도가 높아짐에 따라 활성의 회복 정도가 컸다.

• Earthquakes and Structures
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• 제15권3호
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• pp.227-241
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• 2018

The present paper deals with the optimum performance of the passive hybrid control system for the benchmark highway bridge under the six earthquakes ground motion. The investigation is carried out on a simplified finite element model of the 91/5 highway overcrossing located in Southern California. A viscous fluid damper (known as VFD) or non-linear fluid viscous spring damper has been used as a passive supplement device associated with polynomial friction pendulum isolator (known as PFPI) to form a passive hybrid control system. A parametric study is considered to find out the optimum parameters of the PFPI system for the optimal response of the bridge. The effect of the velocity exponent of the VFD and non-linear FV spring damper on the response of the bridge is carried out by considering different values of velocity exponent. Further, the influences of damping coefficient and vibration period of the dampers are also examined on the response of the bridge. To study the effectiveness of the passive hybrid system on the response of the isolated bridge, it is compared with the corresponding PFPI isolated bridges. The investigation showed that passive supplement damper such as VFD or non-linear FV spring damper associated with PFPI system is significantly reducing the seismic response of the benchmark highway bridge. Further, it is also observed that non-linear FV spring damper hybrid system is a more promising strategy in reducing the response of the bridge compared to the VFD associated hybrid system.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2002년도 제9차 국제심포지움 및 추계정기학술발표회
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• pp.68-68
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• 2002

아열대성 식물 4종 (문주란, Crinum asiaticum var. japonicum; 박달목서, Osmanthus insularis; 죽절초, Chloranthus glaber; 파초일엽, Asplenium antiquum)을 대상으로 자연 환경요인의 변화에 따른 엽록소형광을 분석하여 이들 식물의 활력도를 검토하였다. 여름철 일변화에 있어서 양지에 자라는 문주란과 박달목서는 Fv/Fm이 새벽과 밤에는 0.80~0.83 범위의 높은 값을 보이지만, 낮시간에는 0.65~0.73으로 낮았다. 1-qN과 1-qP도 낮시간에 크게 낮아졌다. 음지에 자라는 죽절초와 파초일엽의 Fv/Fm은 높아서 0.83~0.85 범위를 유지하였으며 일변화적 특성은 관찰되지 않았다. 1-qP의 변화는 거의 관찰되지 않았으나 1-qN이 낮시간에 다소 감소하는 경향을 보여주었다. 죽절초와 파초일엽에서는 광억제가 거의 일어나지 않으나 문주란과 박달목서에서는 낮시간의 고광에 의한 광억제가 나타난다. 하지만 여기에너지의 일부를 열의 형태로 방출하여 광피해를 완화시키고 있는 것으로 보인다. 겨울철에는 Fv/Fm이 모든 종에서 0.8 이하의 값을 나타내었는데, 특히 문주란의 Fv/Fm 값은 다른 3종 보다 더 낮았다. 그리고 모든 종에서 일변화적인 특성은 관찰되지 않았다. 문주란의 1-qN은 낮시간에 다소 감소하였지만, 나머지 3종의 식물은 높은 값을 나타내었다. 그리고 l-qP는 문주란과 박달목서에서는 낮시간에 0.6 범위로 낮아졌다. 이는 종에 따라 차이가 있지만 겨울철 저온의 영향을 받은 결과로 보인다. 한편, 여름철 문주란과 박달목서의 O-J-I-P곡선은 거의 유사하며 낮에 뚜렷하게 낮았고, 죽절초와 파초일엽에서는 일변화적 특성은 두드러지지 않았다. 그리고 P $I_{NO}$ 와 SF $I_{NO}$ 가 죽절초를 제외한 3종에서 여름철 낮시간에 증가하였다. 겨울철의 O-J-I-P곡선은 모든 종에서 낮시간에 다소 낮아지지만 큰 변화는 없었다. 그리고, 문주란, 박달목서, 파초일엽에서 $\psi$o/(1-$\psi$o)가 낮시간에 다소 증가하였다. 이로부터 P $I_{NO}$ , SF $I_{NO}$ , $\psi$o/(1-$\psi$o)등의 변수는 식물의 활력도를 검정하는 지표로 활용될 가능성이 높다고 할 수 있다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.205-205
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• 2017

An excess soil water condition is one of the major problems for the field crops growing in paddy fields because of their poor drainage and less availability for oxygen uptake which leads to adversely affect the photosynthesis. Therefore, the current study was undertaken with aim to investigate the effects groundwater level on the photosynthetic response of soy bean (Urum), red bean (Arari), sesame (Geonbaek), perilla (Dayu) after the transplanting to the lysimeter to investigate the plant-water relation and their effect on photosynthesis. The chlorophyll content of the crops according to the humid conditions of the soy bean, sesame and the perilla was found to be 5%, 6.89 % and 13.7% higher than that of the groundwater treated at 40cm, respectively. On the other hand, the chlorophyll content of adzuki bean decreased 6.6% from the groundwater level of 40cm, and the sorghum decreased by 5.7%. As a result of investigating the Fv / Fm value of groundwater, the adzuki bean at 20cm above groundwater was lower than that of groundwater by 40cm immediately before flowering. The Fv / Fm value of soy bean and sesame at 40cm above groundwater were lowered by flowering under groundwater 20 cm and Fv / Fm value of sorghum is increased at 40 cm treatment immediately before flowering while the Fv / Fm values of the perilla had no significant difference in comparison to those at 20 cm and 40 cm of groundwater. In the case of chlorophyll fluorescence reaction, it is known that the when the absolute value is closer to 0.82, the stress is considered less. As a result of comparing the numerical values of the crops, it was found that the sorghum was the most stressed followed by adzuki bean and sesame, while the soy beans and perilla was found on the average, as they received less stress.

• BMB Reports
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• 제29권5호
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• pp.398-404
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• 1996

Light-chilling effects were investigated in chilling-sensitive cucumber (Cucumis sativus L. cv. Ilmichungjang) and chilling-resistant pea (Pisum sativum L. cv. Giant) leaf discs in relation to possible damage in D1 protein. In both plants, dark-chilling did not cause any noticeable changes in (Fv)m/Fm and lincomycin did not affect the decrease in (Fv)m/Fm caused by light-chilling. This result suggests that the de novo synthesis of D1 protein did not occur actively during light-chilling. In pea light-chilled for 6 h. the decreased (Fv)m/Fm was partly recovered in the dark, and almost complete recovery was observed in the light. In cucumber light-chilled for 3 h. the reduced (Fv)m/Fm decreased further for the initial 2 h recovery process in the light regardless of the treatment of lincomycin and recovered very slowly. In both plant species, the treatment of lincomycin inhibited the recovery process in the light, but did not significantly inhibit the process in the dark. In cucumber leaves pulse-labeled with $[^{35}S]Met$, the labeled band intensities of isolated pigment-protein complexes were almost the same during the 6 h light-chilling, but significant decreases in band intensities were observed during the 3 h recovery period. This result suggests that the irreversibly damaged D1 protein was degraded during the recovery period. However, no noticeable changes were observed in the pea leaves during the 12 h chilling and 3 h recovery period. The polyacrylamide gel electrophoresis of the pigment-protein complexes showed that the principal lesion sites of light-chilling were different from those of room temperature photoinhibition.

• 한국작물학회지
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• 제46권4호
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• pp.296-302
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• 2001

Winter cereals are acclimated during wintering, and thereafter their freezing resistance is increased. In order to analyze inheritance and heritabilities for photoinhibition of photosynthesis by high light intensity under low temperature, and to evaluate the relationship between low temperature-induced photoinhibition and winter survival, 4 parental half diallel crosses were used. The detached leaves of 7-8cm long from plants grown for 35 and 55 days were placed on wet filter paper and placed in trays at 5$^{\circ}C$ cold room with 1,200 $\mu$mol $m^{-2}$ $s^{-1}$ PPFD. Chlorophyll fluorescence was measured with a chlorophyll fluorescence system after dark adaptation for 30 min. The Fv/Fm of 35day old plants was reduced from 0.714 in the control leaves to 0.409 and 0.368 following photoinhibitory treatment of 6h and 8h and the CVs were increased from 0.8% to 22.2-22.3%. The Fv/Fm of 55-day old plants was reduced from 0.775 in the control leaves to 0.485 and 0.439 following photoinhibitory treatment of 10h and 12h, respectively. According to half diallel cross analysis, Reno and Dongbori 1 (highly resistant to photoinhibition) was dominant, but Oweolbori (susceptible to photoinhibition) was recessive, and photoinhibition showed partial dominance with highly additive gene action. Dongbori 1 showed the greatest GCA effects for photoinhibition, and GCA/SCA ratios (8.7-22.3 times) indicated that the additive variance for the character was more important. Winter survival in barley crosses was positively correlated with resistance to photoinhibition and significantly fitted by linear regression ($R^2$=0.751$^{**}$-0.779$^{**}$). The chlorophyll fluorescence measured by Fv/Fm has been found to be highly inheritable and very useful in evaluating relative levels of freezing resistance in barley.ley.

• 한국환경과학회지
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• 제11권10호
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• pp.1023-1030
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• 2002

The effects on photosynthesis of NaCl(0, 0.2, 0.4, 0.6, 0.8 or 1.0 M) were examined in etiolated barley seedlings. Chlorophyll(Chl) a, Chl b and carotenoid contents, Chl a fluorescence and quenching coefficients of Chl fluorescence have been determined in the primary leaves of etiolated barley seedlings cultivated under low light(60 $\mu$㏖ $m^{-2}\;s^{-1}$). Chl a, b, and carotenoid contents were decreased remarkably in comparison with the control at 0.4 M NaCl. However, the value of Fo and Fv were decreased at 0.6 M NaCl and the ratio of Fv/Fm were deceased at 1.0 M NaCl. Chlorophyll synthesis was seriously inhibited from 0.4 M NaCl, and the photosynthetic electron transport system was inhibited from 0.6 M NaCl. Quantum of photosystem II reaction center was inhibited at 1.0 M NaCl. The effects of NaCl on the Chl content were raised in a 6 hrs, but the effects of NaCl on the value of Fo, Fv and Fv/Fm were raised in 30 hrs. The value of qP was decreased in comparison with the control at all concentrations, but there was a small change in the value qE. These results provide evidence that NaCl inhibited effects of various concentration of NaCl were inhibited quinone redox, however, proton gradient between thylakoid membranes was little damaged.

• 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.

• 대한전자공학회논문지SD
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• 제42권11호
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• pp.49-54
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• 2005

본 논문에서는 최소의 sub-window를 사용하여 정확한 초점 값을 측정할 수 있는 모바일 폰 용 저전력 MDCT 초점 값 연산 방식을 제안하였다. 제안된 알고리즘은 기존의 DCT 연산 계수 중 초점 값의 척도로 사용하기에 특성이 가장 우수하고, 하드웨어로 구현하였을 경우 연산량이 최소가 되는 중간 결과 계수를 초점 값으로 사용한다. 또한 중간 주파수에 연관된 DCT 결과를 초점 값으로 사용하므로 임펄스 성 노이즈의 영향을 줄일 수 있고, 영상의 흐린 정도에 따른 초점 값의 변화가 커서기존의 Gradient 방식보다 초점 값 특성이 우수하다. 제안된 알고리즘은 Verilog HDL언어를 사용하여 구현되었으며, Excalibur-ARM보드에 내장하여 그 성능을 검증하였다.