• 한국환경과학회지
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• 제25권8호
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• pp.1143-1153
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• 2016

Plant biomass, photosystem II (PSII) photochemical activity, photosynthetic function, and zinc (Zn) accumulation were investigated in a sorghum-sudangrass hybrid (Sorghum bicolor ${\times}$ S. sudanense) exposed to various Zn concentrations to determine the elimination capacity of Zn from soils. Plant growth and biomass of the sorghum-sudangrass hybrid decreased with increasing Zn concentration. Symptoms of Zn toxicity, i.e., withering and discoloration of old leaves, were found at Zn concentrations over 800 ppm. PSII photochemical activity, as indicated by the values of $F_v/F_m$ and $F_v/F_o$, decreased significantly three days after exposure to Zn concentrations of 800 ppm or more. Photosynthetic $CO_2$ fixation rate (A) was high between Zn concentrations of 100-200 ppm ($22.5{\mu}mol$ $CO_2{\cdot}m^{-2}{\cdot}s^{-1}$), but it declined as Zn concentration increased. At Zn concentrations of 800 and 1600 ppm, A was 14.1 and $1.8{\mu}mol$ $CO_2{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. The patterns of stomatal conductance ($g_s$), transpiration rate (E), and water use efficiency (WUE) were all similar to that of photosynthetic $CO_2$ fixation rate, except for dark respiration ($R_d$), which showed an opposite pattern. Zn was accumulated in both above- and below-ground parts of plants, but was more in the below-ground parts. Magnesium (Mg) and iron (Fe) concentrations were significantly low in the leaves of plants, and symptoms of Mg or Fe deficiency, such as a decrease in the SPAD value, were found when plants were treated with Zn concentrations above 800 ppm. These results suggest that the sorghum-sudangrass hybrid is able to accumulate Zn to high level in plant body and eliminate it with its rapid growth and high biomass yield.

• 한국자원식물학회지
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• 제18권3호
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• pp.441-449
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• 2005

광계II(PSII)는 고등식물의 chloroplast에서 두 개의 광합성 반응중심 중의 하나이다. Chlorophyll a/b 광수확 복합체는 광계II를 위한 안테나 역할을 수행한다. 본 연구에서는 인삼의 잎조직을 제작한 cDNA library로부터 chlorophyll a/b-binding protein (Cab) 유전자를 분리하였다. 인삼 Cab유전자는 935 bp의 염기와 265개의 아미노산 잔기(pI 5.63)로 구성된 한 개의 ORF를 포함하고 있으며, 단백질의 분자량은 28.6 kDa으로 추정되었다. 인삼에서 분리한 Cab 유전자는 기존에 식물에서 보고된 유전자들과 유사성을 나타내었으며, 유사도는 $68-92\%$로 나타났다. 아미노산 서열을 비교하여 유연관계를 분석한 결과 인삼의 Cab 유전자는 비교된 P. persica (AAC34983), A.thaliana (AAD28771), G. hirsutum (CAA38025), G. max (AAL29886), V. radiata (AAF89205) 등과 동일한 그룹으로 분리되었다.

• 한국작물학회지
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• 제61권4호
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• pp.270-276
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• 2016

The objective of this study was to find a rapid determination of the hot air stress in maize (Zea mays L.) leaves using a portable chlorophyll fluorescence imaging instrument. To assess the photosynthetic activity of maize leaves, an imaging analysis of the photochemical responses of maize was performed with chlorophyll fluorescence camera. The observed chlorophyll imaging photos were numerically transformed to the photochemical parameters on the basis of chlorophyll a fluorescence. Chlorophyll a fluorescence imaging (CFI) method showed that a rapid decrease in maximum fluorescence intensity ($F_m$) of leaf occurred under hot air stress. Although no change was observed in the maximum quantum yield ($F_v/F_m$) of the hot air stressed maize leaves, the other photochemical parameters such as maximum fluorescence intensity ($F_m$) and Maximum fluorescence value ($F_p$) were relatively lowered after hot air stress. In hot air stressed maize leaves, an increase was observed in the nonphotoquenching (NPQ) and decrease in the effective quantum yield of photochemical energy conversion in photosystem II (${\Phi}PSII$). Thus, NPQ and ${\Phi}PSII$ were available to be determined non-destructively in maize leaves under hot air stress. Our results clearly indicated that the hot air could be a source of stress in maize leaves. Thus, the CFI analysis along with its related parameters can be used as a rapid indicating technique for the determining hot air stress in plants.

• The Plant Pathology Journal
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• 제32권4호
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• pp.300-310
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• 2016

Pathogen infection in plants induces complex responses ranging from gene expression to metabolic processes in infected plants. In spite of many studies on biotic stress-related changes in host plants, little is known about the metabolic and phenotypic responses of the host plants to Pseudomonas cichorii infection based on image-based analysis. To investigate alterations in tomato plants according to disease severity, we inoculated plants with different cell densities of P. cichorii using dipping and syringe infiltration methods. High-dose inocula (${\geq}10^6cfu/ml$) induced evident necrotic lesions within one day that corresponded to bacterial growth in the infected tissues. Among the chlorophyll fluorescence parameters analyzed, changes in quantum yield of PSII (${\Phi}PSII$) and non-photochemical quenching (NPQ) preceded the appearance of visible symptoms, but maximum quantum efficiency of PSII ($F_v/F_m$) was altered well after symptom development. Visible/near infrared and chlorophyll fluorescence hyperspectral images detected changes before symptom appearance at low-density inoculation. The results of this study indicate that the P. cichorii infection severity can be detected by chlorophyll fluorescence assay and hyperspectral images prior to the onset of visible symptoms, indicating the feasibility of early detection of diseases. However, to detect disease development by hyperspectral imaging, more detailed protocols and analyses are necessary. Taken together, change in chlorophyll fluorescence is a good parameter for early detection of P. cichorii infection in tomato plants. In addition, image-based visualization of infection severity before visual damage appearance will contribute to effective management of plant diseases.

• 한국환경농학회지
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• 제26권3호
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• pp.239-245
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• 2007

The effect of ultraviolet-B (UV-B) radiation on photosynthesis was studied by the simultaneous measurements of $O_2$ evolution and chlorophyll (Chl) fluorescence in tobacco leaves. When the tobacco leaves were teated with UV-B (1 $W{\cdot}m^{-2}$), the maximal photosynthetic $O_2$, evolution (Pmax; 4.60 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) at 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) was decreased with increasing time of UV-B treatment showing 80% decline after 4 h treatment. Chl fluorescence parameters were also affected by ultraviolet-B. Fo was increased while both Fm and Fv were decreased, resulted in the decreased of photochemical efficiency of PSII (Fv/Fm). Non-radiative dissipation of absorbed light as heat as estimated as NPQ (Fm/Fm' - 1) was also decreased with increasing time of UV-B treatment while the extent of photochemical quenching (qP) was not changed. Thus, the ratio of (1-qP)/NPQ parameter was also increased with increasing time of UV-B treatment indicating PSII is under the threat of photoinhibition. The result indicate that UV-B primarily decreases the capacity to dissipate excitation energy by trans-thylakoid pH, which in turn inhibits PSII activity.

• The Plant Pathology Journal
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• 제35권2호
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• pp.112-124
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• 2019

Barley worldwide is affected seriously by Fusarium seedling blight (FSB) and Fusarium head blight (FHB) diseases caused by the Fusarium species. The objective of this study was to facilitate the resistance of hulled and hull-less barley at different growth stages to F. culmorum according to direct parameters: disease rating (DR), fresh weight of leaves and roots, kernel weight per spike, kernel number per spike, plump kernels, and indirect parameters - chlorophyll a fluorescence (CF). Plate assay, greenhouse and field tests were performed on 30 spring barley doubled haploid (DH) lines and their parents infected with Fusarium culmorum. Direct parameters proved that hulled genotypes show less symptoms. Most studied chlorophyll a fluorescence (CF) parameters (apart from DIo/CS - amount of energy dissipated from PSII for laboratory test, TRo/CS - amount of excitation energy trapped in PSII reaction centers, ETo/CS - amount of energy used for electron transport and RC/CS - number of active reaction centres in the state of fully reduced PSII reaction center in field experiment) were significantly affected by F. culmorum infection. In all experiments, hulled genotypes had higher values of CF parameters compared to hull-less ones. Significant correlations were detected between direct and indirect parameters and also between various environments. It was revealed that ABS/CS, TRo/CS, and RC/CS have significant positive correlation in greenhouse test and field experiment. Significant correlations suggest the possibility of applying the CF parameters in selection of barley DH lines resistant to F. culmorum infection.

• Journal of Ecology and Environment
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• 제47권3호
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• pp.85-102
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• 2023

Background: Ecophysiological characteristics of Rosa rugosa were analyzed under different environmental factors from May to October 2022. Photosynthesis, chlorophyll fluorescence, chlorophyll content, leaf water content (LWC), osmolality, carbohydrate content, and total ion content were measured to compare the physiological characteristics of R. rugosa at two study sites (i.e., in large pots and in the Goraebul coastal sand dune area). Results: When R. rugosa was exposed to high temperatures, photosynthetic parameters including net photosynthetic rate (P_N) and stomatal conductance (g_s) in both experiment areas declined. In addition, severe photoinhibition occurs when R. rugosa is continuously exposed to high photosynthetically active radiation (PAR), and because of this, relatively low Y(II) (i.e., the quantum yield of photochemical energy conversion in photosystem II [PSII]) and high Y(NO) (i.e., the quantum yield of non-regulated, non-photochemical energy loss in PSII) in the R. rugosa of the pot were observed. As the high Y(NPQ) (i.e., the quantum yield of regulated non-photochemical energy loss in PSII) of R. rugosa in the coastal sand dune, they dissipated the excessed photon energy through the non-photochemical quenching (NPQ) mechanism when they were exposed to relatively low PAR and low temperature. Rosa rugosa in the coastal sand dune has higher chlorophyll a and carotenoid content. The high chlorophyll a + b and low chlorophyll a/b ratios seemed to optimize light absorption in response to low PAR. High carotenoid content played an important role in NPQ. As a part of the osmotic regulation in response to low LWCs, R. rugosa exposed to high temperatures and continuously high PAR used soluble carbohydrates and ions to maintain high osmolality. Conclusions: We found that F_v/F_m was lower in the potted plants than in the coastal sand dune plants, indicating the vulnerability of R. rugosa to high temperatures and PAR levels. We expect that the suitable habitat range for R. rugosa will shrink and move to north under climate change conditions.

• 한국토양비료학회지
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• 제45권5호
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• pp.676-682
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• 2012

본 연구에서는 생육초기 고추의 한발 스트레스 조건에서 작물 생육에 미치는 영향을 구명하기 위해 엽록소 이미지형 광분석을 이용하여 엽록소 형광 매개변수를 비교분석 하였다. 비록 통계적 유의성이 인정되지는 않았지만 전체 잎의 이미지에 나타나는 형광매개변수들의 평균값은 감소하는 경향이었다. 가변형광값에대한 최대형광값의 비는 변동이 없는 반면, 광계II의 정류상태에서의 양자수득율 및 형광감쇄율은 다소 감소하였다. 이러한 현상은 퀴논 A 단백질로부터 퀴논 B 단백질로의 전자전달의 감소를 의미하였다. 잎의 중앙부위와 엽병부근에서의 비광학적 소광 및 가변형광의 비광학적 소광 상수는 한발스트레스 4일 후 유의성있게 증가하였다. 즉 생리적 스트레스 매개변수로 활용이 가능하였다. 광계II에서의 정류상태 양자수득율의 감소는 고추잎의 모든 부위에서 공통적으로 유의성있게 측정되었다. 결론적으로 ${\Phi}PSII$ ($QY_{_-LSS}$), $NPQ_{_-LSS}$, qN 등의 엽록소형광 매개변수들은 고추의 한발스트레스를 판단할 수 있는 생리적 지표로 활용 가능한 것으로 유의성이 인정되었다.

• 한국작물학회지
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• 제60권1호
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• pp.1-7
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• 2015

본 연구는 파종시기와 질소시비 수준에 대한 옥수수의 광화학적 반응을 분석하여 광생리적 특성을 해석하였다. 1. 5월 22일 파종시 질소 함량이 증가함에 따라 생육후기까지 엽록소 형광량 또한 증가하여 질소 배량처리에서 광이용효율이 더 높은 것으로 확인되었다. 2. 생육초기의 형광량이 가장 높았으며, 이후 모든 처리구에서 엽록소 형광량이 50% 가량 감소하여 전자전달을 위한 광화학 반응이 크게 감소했음을 알 수 있었다. 3. 질소 반량구에서 활성화된 RC (RC/ABS)가 감소하며 13% 이상의 에너지가 손실되었으며, 결국 전자전달시 에너지 전환효율(PI, DF 등)이 감소해 광이용효율이 낮았다. 4. 배량 처리구는 생육후기로 갈수록 전자전달 효율(ET2o/CS) 및 단면당 활성화된 RC(RC/CS) 등 광이용 효율이 대조구 대비 크게 증가하여 광합성기구 사이의 전자전달이 잘 이루어지는 것으로 확인되었다.

• 한국해양학회지:바다
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• 제14권2호
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• pp.118-126
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• 2009

저서규조류는 하구역 먹이망을 이해하는 데 중요한 생물로서 그들의 광생리 특성에 따라 일차생산력이 크게 변화한다. 본 연구에서는 단기간 온도 변화가 저서규조류 4종(Navicula sp., Nitzschia sp., Cylindrotheca closterium, Pleurosigma elongatum)의 광합성 반응에 미치는 영향을 Diving PAM을 이용한 엽록소 형광 분석법으로 측정하여 광생리 특성을 분석하였다. 6개의 온도 조건(10, 15, 20, 25, 30, $35^{\circ}C$)에서 2시간 간격으로 24시간 동안 엽록소 형광을 측정하여 P-I 곡선을 도출하였다. 제2광계의 유효양자수율($\Phi_{PSII}$)은 대부분의 종에 있어서 온도가 증가함에 따라 감소하였으며, 상대 최대 전자전달율(rETRmax)은 최적 온도까지 증가한 후 급격하게 감소하였다. 최대 빛이용 효율($\alpha$)은 다른 광합성 매개변수에 비해 온도에 덜 민감하였으나, 높은 온도에서는 감소하였으며, 광포화 계수($E_K$)는 상대 최대 전자전달율의 반응과 매우 유사하였다. 종별 광생리 특성을 분석한 결과, Navicula sp.와 Cylindeotheca closterium가 광생리적 조절을 통하여 단시간의 온도 변화에 광순응하는 것을 확인할 수 있었다.