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Sample records for survival chlorophyll fluorescence

  1. Salt stress change chlorophyll fluorescence in mango

    Directory of Open Access Journals (Sweden)

    Cicero Cartaxo de Lucena

    2012-12-01

    Full Text Available This study evaluated the tolerance of mango cultivars 'Haden', 'Palmer', 'Tommy Atkins' and 'Uba' grafted on rootstock 'Imbú' to salt stress using chlorophyll fluorescence. Plants were grown in modified Hoagland solution containing 0, 15, 30, and 45 mmol L-1 NaCl. At 97 days the parameters of the chlorophyll fluorescence (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv'/Fm', ΦPSII = [(Fm'-Fs/(Fm'], D = (1- Fv'/Fm' and ETR = (ΦPSII×PPF×0,84×0,5 were determined. At 100 days, the leaf emission and leaf area, toxicity and leaf abscission indexes were determined. In all cultivars evaluated, in different degree, there were decreases in photochemical efficiency of photosystem II, enhanced concentrations from 15 mmol L-1 NaCl. The decreases in the potential quantum yield of photosystem II (Fv/Fm were 27.9, 18.7, 20.5, and 27.4%, for cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba', respectively, when grown in 45 mmol L-1 NaCl. It was found decreases in leaf emission and mean leaf area in all cultivars from 15 mmol L-1 NaCl. There were increases in leaf toxicity of 33.0, 67.5, 41.6 and 80.8% and in leaf abscission of 71.8, 29.2, 32.5, and 67.9% for the cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba' respectively, when grown in 45 mmol L-1 NaCl. Leaf toxicity and leaf abscission were not observed in 15 mmol L-1 NaCl. The decrease in Fv/Fm ratio were accompanied by decreasing in leaf emission and increased leaf toxicity index, showing, therefore, the potential of chlorophyll fluorescence in the early detection of salt stress in mango tree.

  2. A model for chlorophyll fluorescence and photosynthesis at leaf scale

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    Tol, van der C.; Verhoef, W.; Rosema, A.

    2009-01-01

    This paper presents a leaf biochemical model for steady-state chlorophyll fluorescence and photosynthesis of C3 and C4 vegetation. The model is a tool to study the relationship between passively measured steady-state chlorophyll fluorescence and actual photosynthesis, and its evolution during the

  3. APPLICATION OF MODULATED CHLOROPHYLL FLUORESCENCE AND MODULATED CHLOROPHYLL FLUORESCENCE IMAGING IN STUDYING ENVIRONMENTAL STRESSES EFFECT

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    L. Guidi

    2016-03-01

    Full Text Available Chlorophyll (Chl a fluorescence is a widely used tool to monitor the photosynthetic process in plants subjected to environmental stresses.this review reports the theoretical bases of Chl fluorescence, and the significance of the most important Chl fluorescence parameters. it also reportshow these parameters can be utilised to estimate changes in photosystem ii (PSII photochemistry, linear electron flux and energy dissipationmechanisms. the relation between actual PSII photochemistry and CO2 assimilation is discussed, as is the role of photochemical andnon-photochemical quenching in inducing changes in PSII activity. the application of Chl fluorescence imaging to study heterogeneity on leaflamina is also considered. this review summarises only some of the results obtained by this methodology to study the effects of differentenvironmental stresses, namely water and nutrients availability, pollutants, temperature and salinity.

  4. Tomato seeds maturity detection system based on chlorophyll fluorescence

    Science.gov (United States)

    Li, Cuiling; Wang, Xiu; Meng, Zhijun

    2016-10-01

    Chlorophyll fluorescence intensity can be used as seed maturity and quality evaluation indicator. Chlorophyll fluorescence intensity of seed coats is tested to judge the level of chlorophyll content in seeds, and further to judge the maturity and quality of seeds. This research developed a detection system of tomato seeds maturity based on chlorophyll fluorescence spectrum technology, the system included an excitation light source unit, a fluorescent signal acquisition unit and a data processing unit. The excitation light source unit consisted of two high power LEDs, two radiators and two constant current power supplies, and it was designed to excite chlorophyll fluorescence of tomato seeds. The fluorescent signal acquisition unit was made up of a fluorescence spectrometer, an optical fiber, an optical fiber scaffolds and a narrowband filter. The data processing unit mainly included a computer. Tomato fruits of green ripe stage, discoloration stage, firm ripe stage and full ripe stage were harvested, and their seeds were collected directly. In this research, the developed tomato seeds maturity testing system was used to collect fluorescence spectrums of tomato seeds of different maturities. Principal component analysis (PCA) method was utilized to reduce the dimension of spectral data and extract principal components, and PCA was combined with linear discriminant analysis (LDA) to establish discriminant model of tomato seeds maturity, the discriminant accuracy was greater than 90%. Research results show that using chlorophyll fluorescence spectrum technology is feasible for seeds maturity detection, and the developed tomato seeds maturity testing system has high detection accuracy.

  5. An overview of remote sensing of chlorophyll fluorescence

    Science.gov (United States)

    Xing, Xiao-Gang; Zhao, Dong-Zhi; Liu, Yu-Guang; Yang, Jian-Hong; Xiu, Peng; Wang, Lin

    2007-03-01

    Besides empirical algorithms with the blue-green ratio, the algorithms based on fluorescence are also important and valid methods for retrieving chlorophyll-a concentration in the ocean waters, especially for Case II waters and the sea with algal blooming. This study reviews the history of initial cognitions, investigations and detailed approaches towards chlorophyll fluorescence, and then introduces the biological mechanism of fluorescence remote sensing and main spectral characteristics such as the positive correlation between fluorescence and chlorophyll concentration, the red shift phenomena. Meanwhile, there exist many influence factors that increase complexity of fluorescence remote sensing, such as fluorescence quantum yield, physiological status of various algae, substances with related optical property in the ocean, atmospheric absorption etc. Based on these cognitions, scientists have found two ways to calculate the amount of fluorescence detected by ocean color sensors: fluorescence line height and reflectance ratio. These two ways are currently the foundation for retrieval of chlorophyl l - a concentration in the ocean. As the in-situ measurements and synchronous satellite data are continuously being accumulated, the fluorescence remote sensing of chlorophyll-a concentration in Case II waters should be recognized more thoroughly and new algorithms could be expected.

  6. CHLOROPHYLL a FLUORESCENCE ANALYSIS IN FORESTS

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    M. Pollastrini

    2016-03-01

    Full Text Available A European-wide assessment of chlorophyll a fluorescence (ChlF, prompt fluorescence on dark-adapted samples parameters in forest ecosystems was carried out in the years 2012-2013, within the 7FP FunDivEUROPE project. A total of 1596 trees growing in 209 stands distributed in six countries, from Mediterranean to boreal sites, were sampled. This paper shows the applicability of the ChlF in forest ecology surveys, the protocols adopted for leaf sampling and ChlF measurements, the variability of the ChlF parameters within and between trees, their dependence to environmental factors and the relationships with other functional leaf traits. The most relevant findings were as follows: (i The least variable ChlF parameter within and between the trees was the maximum quantum yield of primary photochemistry (FV/FM, whereas the performance indices (PIABS and PITOT showed the highest variability; (ii for a given tree, the ChlF parameters measured at two heights of the crown (top and bottom leaves were correlated and, in coniferous species, the ChlF parameters were correlated between different needle age classes (from the current year and previous year; (iii the ChlF parameters showed a geographical pattern, and the photochemical performance of the forest trees was higher in central Europe than in the edge sites (northernmost and southernmost; and (iv ChlF parameters showed different sensitivity to specific environmental factors: FV/FM increased with the increase of the leaf area index of stands and soil fertility; ΔVIP was reduced under high temperature and drought. The photochemical responses of forest tree species, analyzed with ChlF parameters, were influenced by the ecology of the trees (i.e. their functional groups, continental distribution, successional status, etc., tree species’ richness and composition of the stands. Our results support the applicability and usefulness of the ChlF in forest monitoring investigations on a large spatial scale and

  7. TEMPERATURE EFFECTS ON CHLOROPHYLL FLUORESCENCE INDUCTION IN TOMATO

    NARCIS (Netherlands)

    JANSSEN, LHJ; VANHASSELT, PR

    Chlorophyll fluorescence induction of tomato leaf discs was measured at a low actinic light intensity of 10 mu mol.m(-2).s(-1) and at decreasing temperatures from 30 degrees to 0 degrees C. F-o remained constant within the temperature range assessed. In contrast, the peak of fluorescence induction,

  8. Chlorophyll Fluorescence Imaging Uncovers Photosynthetic Fingerprint of Citrus Huanglongbing

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    Haiyan Cen

    2017-08-01

    Full Text Available Huanglongbing (HLB is one of the most destructive diseases of citrus, which has posed a serious threat to the global citrus production. This research was aimed to explore the use of chlorophyll fluorescence imaging combined with feature selection to characterize and detect the HLB disease. Chlorophyll fluorescence images of citrus leaf samples were measured by an in-house chlorophyll fluorescence imaging system. The commonly used chlorophyll fluorescence parameters provided the first screening of HLB disease. To further explore the photosynthetic fingerprint of HLB infected leaves, three feature selection methods combined with the supervised classifiers were employed to identify the unique fluorescence signature of HLB and perform the three-class classification (i.e., healthy, HLB infected, and nutrient deficient leaves. Unlike the commonly used fluorescence parameters, this novel data-driven approach by using the combination of the mean fluorescence parameters and image features gave the best classification performance with the accuracy of 97%, and presented a better interpretation for the spatial heterogeneity of photochemical and non-photochemical components in HLB infected citrus leaves. These results imply the potential of the proposed approach for the citrus HLB disease diagnosis, and also provide a valuable insight for the photosynthetic response to the HLB disease.

  9. Instrumentation in Developing Chlorophyll Fluorescence Biosensing: A Review

    Science.gov (United States)

    Fernandez-Jaramillo, Arturo A.; Duarte-Galvan, Carlos; Contreras-Medina, Luis M.; Torres-Pacheco, Irineo; de J. Romero-Troncoso, Rene; Guevara-Gonzalez, Ramon G.; Millan-Almaraz, Jesus R.

    2012-01-01

    Chlorophyll fluorescence can be defined as the red and far-red light emitted by photosynthetic tissue when it is excited by a light source. This is an important phenomenon which permits investigators to obtain important information about the state of health of a photosynthetic sample. This article reviews the current state of the art knowledge regarding the design of new chlorophyll fluorescence sensing systems, providing appropriate information about processes, instrumentation and electronic devices. These types of systems and applications can be created to determine both comfort conditions and current problems within a given subject. The procedure to measure chlorophyll fluorescence is commonly split into two main parts; the first involves chlorophyll excitation, for which there are passive or active methods. The second part of the procedure is to closely measure the chlorophyll fluorescence response with specialized instrumentation systems. Such systems utilize several methods, each with different characteristics regarding to cost, resolution, ease of processing or portability. These methods for the most part include cameras, photodiodes and satellite images. PMID:23112686

  10. Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence

    National Research Council Canada - National Science Library

    Vogelmann, T. C; Evans, J. R

    2002-01-01

    .... For chlorophyll solutions, the intensity of the emitted fluorescence declined in a log–linear manner with the distance from  the  irradiated  surface  as  predicted  by  Beer's  law...

  11. Relationship of intertidal surface sediment chlorophyll concentration to hyper-spectral reflectance and chlorophyll fluorescence

    NARCIS (Netherlands)

    Kromkamp, J.C.; Morris, E.P.; Forster, R.M.; Honeywill, C.; Hagerthey, S.; Paterson, D.M.

    2006-01-01

    Estimating biomass of microphytobenthos (MPB) on intertidal mud flats is extremely difficult due to their patchy occurrence, especially at the scale of an entire mud flat. We tested two optical approaches that can be applied in situ: spectral reflectance and chlorophyll fluorescence. These two

  12. Modelling chlorophyll fluorescence of kiwi fruit (Actinidia deliciosa).

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    Novo, Johanna Mendes; Iriel, Analia; Lagorio, M Gabriela

    2012-04-01

    Kiwi fruit displays chlorophyll fluorescence. A physical model was developed to reproduce the observed original fluorescence for the whole fruit, from the emission of the different parts of the kiwi fruit. The spectral distribution of fluorescence in each part of the fruit, was corrected to eliminate distortions due to light re-absorption and it was analyzed in relation to photosystem II-photosystem I ratio. Kiwi fruit also displays variable chlorophyll-fluorescence, similar to that observed from leaves. The maximum quantum efficiency of photosystem II photochemistry (F(v)/F(m)), the quantum efficiency of photosystem II (Φ(PSII)), and the photochemical and non-photochemical quenching coefficients (q(P) and q(NP) respectively) were determined and discussed in terms of the model developed. The study was extended by determining the photosynthetic parameters as a function of the storage time, at both 4 °C and room temperature for 25 days.

  13. Ambiguous dependence of fluorescence intensity of trees on chlorophyll concentration

    Science.gov (United States)

    Zavoruev, Valeriy V.; Zavorueva, Elena N.

    2014-11-01

    Using fluorimetry Junior PAM (Heinz Walz GmbH, Germany) fluorescence parameters of leaves Prinsepia sinensis, Crataegus chlorocarca M, Acer negúndo, Bétula péndula are studied. It was found that the dependence of maximum fluorescence (Fm) plants on the concentration of chlorophyll depends on the sampling method during of vegetation. The correctness of sampling proves during vegetation is substantiated.

  14. Content and fluorescence of chlorophyll in eucalypt exposed to glyphosate

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    Leonardo Bianco de Carvalho

    2016-03-01

    Full Text Available The objective was to evaluate the response of eucalypt clonal (Eucalyptus urograndis regarding on chlorophyll content and fluorescence of chlorophyll after glyphosate spraying to verify if the herbicide affects the photochemical process of photosynthesis. Plants of four eucalypt clonal (C219, GG100, I144, and I224, having four expanded leaves, were sprayed with glyphosate in range of doses varying from 0 up to 720 g ae ha-1. We evaluated the chlorophyll content and the relation Fv/Fm during 30 days after spraying glyphosate. The chlorophyll content of the clone C219 reduced by 12% at doses ≥ 360 g ae ha-1. In addition, chlorophyll content was higher (≥ 12% in all clonal from 7 days after spraying. The relation Fv/Fm did not alter after glyphosate spraying. We concluded that the efficiency of the photosystem II is not influenced by glyphosate in any studied eucalypt clonal, although doses of glyphosate from 360 g ae ha-1 affect the chlorophyll content of the clonal C219.

  15. Chlorophyll Fluorescence Analysis of Cyanobacterial Photosynthesis and Acclimation

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    Campbell, Douglas; Hurry, Vaughan; Clarke, Adrian K.; Gustafsson, Petter; Öquist, Gunnar

    1998-01-01

    Cyanobacteria are ecologically important photosynthetic prokaryotes that also serve as popular model organisms for studies of photosynthesis and gene regulation. Both molecular and ecological studies of cyanobacteria benefit from real-time information on photosynthesis and acclimation. Monitoring in vivo chlorophyll fluorescence can provide noninvasive measures of photosynthetic physiology in a wide range of cyanobacteria and cyanolichens and requires only small samples. Cyanobacterial fluorescence patterns are distinct from those of plants, because of key structural and functional properties of cyanobacteria. These include significant fluorescence emission from the light-harvesting phycobiliproteins; large and rapid changes in fluorescence yield (state transitions) which depend on metabolic and environmental conditions; and flexible, overlapping respiratory and photosynthetic electron transport chains. The fluorescence parameters FV/FM, FV′/FM′,qp,qN, NPQ, and φPS II were originally developed to extract information from the fluorescence signals of higher plants. In this review, we consider how the special properties of cyanobacteria can be accommodated and used to extract biologically useful information from cyanobacterial in vivo chlorophyll fluorescence signals. We describe how the pattern of fluorescence yield versus light intensity can be used to predict the acclimated light level for a cyanobacterial population, giving information valuable for both laboratory and field studies of acclimation processes. The size of the change in fluorescence yield during dark-to-light transitions can provide information on respiration and the iron status of the cyanobacteria. Finally, fluorescence parameters can be used to estimate the electron transport rate at the acclimated growth light intensity. PMID:9729605

  16. Gas exchange and chlorophyll a fluorescence parameters of ornamental bromeliads

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    Karina Gonçalves da Silva

    2017-10-01

    Full Text Available Gas exchange and chlorophyll a fluorescence are widely used in physiological and ecological studies; however, few studies have used these techniques with ornamental plants. This study tested the potential contribution of gas exchange and chlorophyll a fluorescence to evaluate the water and nutrients uptake by the tank and root system of epiphyte bromeliad Guzmania lingulata. For this purpose, we conducted an experiment with different water regime and another with different concentrations of nitrogen. The experiments were: 1 - Watering: Control (application of water into Tank and Root, Tank (watering into Tank, Root (watering Root and Drought (water suspension during the 90 days of experimentation and 2 - Nitrogen: Plants fertilized with Hoagland and Arnon nutrient solution exclusively into Tank or Root with nitrogen concentrations of control and 2.62 or 5.34 mM N applied as urea. The Fv /Fm ratio allowed comparing the treatments between experiments, demonstrating that Root and Tank both have the capacity to maintain G. lingulata photosynthetic activity and growth, while Drought treatment (water suspension was the limiting factor for energy conversion efficiency of PSII. However, gas exchange was more permissive as a parameter for comparing treatments in the nitrogen experiment, providing important information about the general aspects of the photosynthetic process in the watering experiment. Both gas exchange and chlorophyll a fluorescence can support the evaluation of G. lingulata physiological status and can be useful tools in ornamental horticultural studies.

  17. Interpreting chlorophyll fluorescence signals: the effects of leaf age

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    Albert, L.; Vergeli, P.; Martins, G.; Saleska, S. R.; Huxman, T. E.

    2015-12-01

    Remote sensing of sun-induced chlorophyll fluorescence (SIF) promises robust estimation of carbon uptake across landscapes, as studies of plant physiology have shown that fluorescence emission is directly linked to photosynthesis at the leaf level. Yet most leaf-level studies demonstrating the link between chlorophyll fluorescence and photosynthesis have studied leaves in their prime: leaves that recently finished expansion and have yet to senesce. By contrast, remote sensing of landscapes involves observing leaves of different ages. For example, broadleaf deciduous forests and annual plant communities in temperate regions have leaves that develop and then senesce over the course of a growing season. In this experiment, we explored how leaf age and moisture availability affect steady-state fluoresence (Fs) at the leaf level. We simultaneously measured net photosynthesis (Anet) and Fs for leaves of known ages on greenhouse-grown dwarf Helianthus Annuus (sunflowers) from two watering treatments. To monitor plant water status, we measured pre-dawn water potential, and, for a subset of leaves, osmotic potential. Fully expanded or near-fully expanded leaves (~8 to ~23 days old) had higher Anet at saturating light than young, expanding leaves (less than 8 days old) or old leaves nearing senescence (>23 days old). We found a positive relationship between Fs and Anet, suggesting that the link between fluorescence emission and photosynthesis is robust across leaves of different ages. However, leaf age had marked effects on the light response curve of photosynthesis and fluorescence metrics. These results suggest that leaf age distribution, and changes in leaf age distribution due to phenology, should be considered when interpreting SIF at the landscape level.

  18. Contribution of chlorophyll fluorescence to the apparent vegetation reflectance

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, P.K. Entcheva [Joint Center for Earth Systems Technology, UMBC, Baltimore, MD 21228 (United States); Biospheric Sciences Branch, Hydrospheric and Biospheric Sciences Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States)], E-mail: pcampbel@pop900.gsfc.nasa.gov; Middleton, E.M. [Biospheric Sciences Branch, Hydrospheric and Biospheric Sciences Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States); Corp, L.A. [Biospheric Sciences Branch, Hydrospheric and Biospheric Sciences Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States); Agricultural Research Service, USDA, Beltsville, MD 20705 (United States); Kim, M.S. [Agricultural Research Service, USDA, Beltsville, MD 20705 (United States)

    2008-10-15

    Current strategies for monitoring the physiologic status of terrestrial vegetation rely on remote sensing reflectance data, which provide estimates of vigor based primarily on chlorophyll content. Chlorophyll fluorescence (ChlF) measurements offer a non-destructive alternative and a more direct approach for diagnosis of vegetation stress before a significant reduction in chlorophyll content has occurred. Thus, technology based on ChlF may allow more accurate carbon sequestration estimates and earlier stress detection than is possible when using reflectance data alone. However, the observed apparent vegetation reflectance (Ra) in reality includes contributions from both the reflected and fluoresced radiation. The aim of this study is to determine the relative contributions of reflectance and ChlF fractions to Ra in the red to near-infrared region (650-800 nm) of the spectrum. The practical objectives of the study are to: 1) evaluate the relationship between ChlF and reflectance at the foliar level for corn, soybean and maple; and 2) for corn, determine if the relationship established for healthy vegetation changes under nitrogen (N) deficiency. To obtain generally applicable results, experimental measurements were conducted on unrelated crop and tree species (corn, soybean and maple) under controlled conditions and a gradient of inorganic N fertilization levels. Optical reflectance spectra and actively induced ChlF emissions were collected on the same foliar samples, in conjunction with measurements of photosynthetic function, pigment levels, and carbon (C) and N content. The spectral trends were examined for similarities. On average, 10-20% of Ra at 685 nm was actually due to ChlF. The spectral trends in steady state and maximum fluorescence varied significantly, with steady state fluorescence (especially red, 685 nm) showing higher ability for species and treatment separation. The relative contribution of ChlF to Ra varied significantly among species, with maple

  19. Applications of chlorophyll fluorescence can improve crop production strategies: an examination of future possibilities

    National Research Council Canada - National Science Library

    Neil R. Baker; Eva Rosenqvist

    2004-01-01

    .... Finally, consideration is given to possible specific applications of chlorophyll fluorescence for screening of plants for tolerance to environmental stresses and for improvements in glasshouse...

  20. The effect of storage temperature of cucumber fruit on chlorophyll fluorescence

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    Ryszard Kosson

    2013-12-01

    Full Text Available The effect of three storage temperature levels: 12,5°C, 20°C, and 1,5°C on basic indexes of chlorophyll fluorescence of cucumber fruits was studied. The greenhouse grown cucumber fruits cv. Wiktor F1 were stored in perforated polyethylene bags or without packages. The minimum chlorophyll fluorescence (Fo, maximum chlorophyll fluorescence (Fm, variable chlorophyll fluorescence (Fv and relative variable fluorescence (Fv/Fm of the cucumber peel were measured. Relative variable fluorescence was decTeasing when cucumbers were stored at temperature lower or higher than optimum level. The chlorophyll fluorescence measurements can be helpful for determination of appropriate temperature parameters of cucumber storage.

  1. Variability of the specific fluorescence of chlorophyll in the ocean. Part 2. Fluorometric method of chlorophyll a determination

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    Miros³awa Ostrowska

    2000-06-01

    Full Text Available Two methods of determining the chlorophyll a concentration in the sea have been formulated on the basis of artificially induced fluorescence measured with the aid of submersible fluorometers. The method of statistical correlation is founded on the empirical relationship between fluorescence and chlorophyll concentration. The theoretical model of fluorescence described in Part 1 of this paper (see Ostrowska et al. 2000, this volume provides the basis of the other method, the physical method. This describes the dependence of the specific fluorescence of phytoplankton on the chlorophyll concentration, a diversity of photophysiological properties of phytoplankton and the optical characteristics of the fluorometer.     In order to assess their practicability, the methods were subjected to empirical verification. This showed that the physical method yielded chlorophyll concentrations of far greater accuracy. The respective error factors of the estimated chlorophyll concentration were x = 2.07 for the correlation method and x = 1.5 for the physical method. This means that the statistical logarithmic error varies from -52 to +107% in the case of the former method but only from -33 to +51% in the case of the latter. Thus, modifying the methodology has much improved the accuracy of chlorophyll determinations.

  2. Effects of salinity and nutrients on the growth and chlorophyll fluorescence of Caulerpa lentillifera

    Science.gov (United States)

    Guo, Hui; Yao, Jianting; Sun, Zhongmin; Duan, Delin

    2015-03-01

    Caulerpa lentillifera is a green algae that distributes worldwide and is cultivated for food. We assessed vegetative propagation of C. lentillifera by measuring the specific growth rate (SGR) and chlorophyll fluorescence of the green algae cultured at different salinities and nutrient levels. The results indicated that C. lentillifera can survive in salinities ranging from 20 to 50, and can develop at salinities of 30 to 40. The maximum SGR for C. lentillifera occurred at a salinity of 35. Both chlorophyll content and the ratio of variable to maximum fluorescence ( F v/ F m) were also at a maximum at a salinity of 35. Photosynthesis was inhibited in salinities greater than 45 and less than 25. Both the maximum SGR and maximum chlorophyll content were found in algae treated with a concentration of 0.5 mmol/L of NO3-N and 0.1 mmol/L of PO4-P. The photosynthetic capacity of photosystem II (PSII) was inhibited in cultures of C. lentillifera at high nutrient levels. This occurred when NO3-N concentrations were greater than 1.0 mmol/L and when PO4-P concentrations were at 0.4 mmol/L. As there is strong need for large-scale cultivation of C. lentillifera, these data contribute important information to ensure optimal results.

  3. Cytokinin-induced changes in the chlorophyll content and fluorescence of in vitro apple leaves.

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    Dobránszki, Judit; Mendler-Drienyovszki, Nóra

    2014-10-15

    Cytokinins (CKs) are one of the main regulators of in vitro growth and development and might affect the developmental state and function of the photosynthetic apparatus of in vitro shoots. Effects of different cytokinin regimes including different types of aromatic cytokinins, such as benzyl-adenine, benzyl-adenine riboside and 3-hydroxy-benzyladenine alone or in combination were studied on the capacity of the photosynthetic apparatus and the pigment content of in vitro apple leaves after 3 weeks of culture. We found that the type of cytokinins affected both chlorophyll a and b contents and its ratio. Chlorophyll content of in vitro apple leaves was the highest when benzyl-adenine was applied as a single source of cytokinin in the medium (1846-2176 μg/1g fresh weight (FW) of the leaf). Increasing the concentration of benzyl-adenine riboside significantly decreased the chlorophyll content of the leaves (from 1923 to 1183 μg/1g FW). The highest chl a/chl b ratio was detected after application of meta-topolin (TOP) at concentrations of 2.0 and 6.0 μM (2.706 and 2.804). Chlorophyll fluorescence was measured both in dark-adapted (Fv/Fm test) and in light-adapted leaf samples (Yield test; Y(II)). The maximum quantum yield and efficiency of leaves depended on the cytokinin source of the medium varied between 0.683 and 0.861 (Fv/Fm) indicating a well-developed and functional photosynthetic apparatus. Our results indicate that the type and concentration of aromatic cytokinins applied in the medium affect the chlorophyll content of the leaves in in vitro apple shoots. Performance of the photosynthetic apparatus measured by chlorophyll fluorescence in the leaves was also modified by the cytokinin supply. This is the first ever study on the relationship between the cytokinin supply and the functionability of photosystem II in plant tissue culture and our findings might help to increase plantlet survival after transfer to ex vitro conditions. Copyright © 2014 Elsevier Gmb

  4. Chlorophyll fluorescence extraction from water-leaving radiance of algae-containing water through polarization

    Science.gov (United States)

    Wang, Lin; Qiu, Zhongfeng; Pang, Huifang; Liu, Yongjian; Chen, Yanlong; Jiang, Lingling

    2017-12-01

    When measuring reflectance spectra, it is very important to accurately extract chlorophyll fluorescence from elastic- scattering light in water-leaving radiance. The elastic scattering of light by water particles produces partially polarized light. In contrast, chlorophyll fluorescence in planktonic algae yields completely unpolarized light. These properties can be used to separate fluorescent signals from the water-leaving radiance and thus to determine chlorophyll concentration. The algal species Aureococcus anophagefferens was used to conduct a laboratory polarization experiment. For the tests, we used a field spectroradiometer and a polarizer; measurements were collected using two different observation modes. The chlorophyll fluorescence curve extracted through polarization shows an excellent match with the results obtained using the fluorospectro photometer for both measurement modes, suggesting that polarization-based chlorophyll fluorescence extraction may be feasible. The extracted fluorescence is more reliable at incident zenith angles ranging from 30° to 60°. For algae-containing water, the results improve with increasing chlorophyll concentration. This method could help improve chlorophyll concentration measurement and the remote-sensing detection of resulting harmful algae blooms.

  5. Remote Sensing of Chlorophyll Fluorescence by the Airborne Plant Fluorescence Sensor (APFS)

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    Yee, J. H.; Boldt, J.; Cook, W. B.; Morgan, F., II; Demajistre, R.; Cook, B. D.; Corp, L. A.

    2014-12-01

    Solar-induced chlorophyll fluorescence (ChlF) by terrestrial vegetation is linked closely to photosynthetic efficiency that can be exploited to monitor the plant health status and to assess the terrestrial carbon budget from space. The weak, broad continuum ChlF signal can be detected from the amount of fill-in of strong O2 absorption lines or Fraunhofer lines in the reflected solar spectral radiation. The Johns Hopkins University, Applied Physics Laboratory (JHU/APL) Airborne Plant Fluorescence Sensor (APFS) is designed and constructed specifically for airborne and groundbased ChlF measurements using the line fill-in ChlF measurement technique. In this paper, we will present the design of this triple etalon Fabry-Perot imaging instrument and the results of its vegetation fluorescence measurements obtained from the ground in the laboratory and from a NASA Langley King Air during our 2014 airborne campaign over vegetated targets in North Carolina and Virginia.

  6. FO-spectra of chlorophyll fluorescence for the determination of zooplankton grazing

    NARCIS (Netherlands)

    Lürling, M.; Verschoor, A.M.

    2003-01-01

    In the PHYTO-PAM phytoplankton analyzer the minimal fluorescence of dark-adapted samples (F0) was assessed, which gives direct information on the chlorophyll- a content. Clearance rates (CR) of Daphnia and Brachionus were calculated from a decrease in chlorophyll-a concentration using the PHYTO-PAM

  7. Fo-spectra of chlorophyll fluorescence for the determination of zooplankton grazing

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Verschoor, A.M.

    2003-01-01

    In the PHYTO-PAM phytoplankton analyzer the minimal fluorescence of dark-adapted samples (F-0) was assessed, which gives direct information on the chlorophyll-a content. Clearance rates (CR) of Daphnia and Brachionus were calculated from a decrease in chlorophyll-a concentration using the PHYTO-PAM

  8. Multiangular Observation of Canopy Sun-Induced Chlorophyll Fluorescence by Combining Imaging Spectroscopy and Stereoscopy

    National Research Council Canada - National Science Library

    Francisco Pinto; Mark Müller-Linow; Anke Schickling; M Pilar Cendrero-Mateo; Agim Ballvora; Uwe Rascher

    2017-01-01

    The effect that the canopy structure and the viewing geometry have on the intensity and the spatial distribution of passively measured sun-induced chlorophyll fluorescence at canopy scale is still not well understood...

  9. Overview of Global Monitoring of Terrestrial Chlorophyll Fluorescence from Space

    Science.gov (United States)

    Guanter, Luis; Zhang, Yongguang; Kohler, Philipp; Walther, Sophia; Frankenberg, Christian; Joiner, Joanna

    2016-01-01

    Despite the critical importance of photosynthesis for the Earth system, understanding how it is influenced by factors such as climate variability, disturbance history, and water or nutrient availability remains a challenge because of the complex interactions and the lack of GPP measurements at various temporal and spatial scales. Space observations of the sun-induced chlorophyll fluorescence (SIF) electromagnetic signal emitted by plants in the 650-850nm spectral range hold the promise of providing a new view of vegetation photosynthesis on a global basis. Global retrievals of SIF from space have recently been achieved from a number of spaceborne spectrometers originally intended for atmospheric research. Despite not having been designed for land applications, such instruments have turned out to provide the necessary spectral and radiometric sensitivity for SIF retrieval from space. The first global measurements of SIF were achieved in 2011 from spectra acquired by the Japanese GOSAT mission launched in 2009. The retrieval takes advantage of the high spectral resolution provided by GOSATs Fourier Transform Spectrometer (FTS) which allows the evaluation of the in-filling of solar Fraunhofer lines by SIF. Unfortunately, GOSAT only provides a sparse spatial sampling with individual soundings separated by several hundred kilometers. Complementary, the Global Ozone Monitoring Experiment-2 (GOME-2) instruments onboard MetOp-A and MetOp-B enable SIF retrievals since 2007 with a continuous and global spatial coverage. GOME-2 measures in the red and near-infrared (NIR) spectral regions with a spectral resolution of 0.5 nm and a pixel size of up to 40x40 km2. Most recently, another global and spatially continuous data set of SIF retrievals at 740 nm spanning the 2003-2012 time frame has been produced from ENVISATSCIAMACHY. This observational scenario has been completed by the first fluorescence data from the NASA-JPL OCO-2 mission (launched in July 2014) and the upcoming

  10. Spectral and physiological information from chlorophyll fluorescence signals in the detection of pine damage

    Energy Technology Data Exchange (ETDEWEB)

    Meinander, O. [Finnish Meteorological Inst., Helsinki (Finland). Air Quality Dept.; Somersalo, S. [Helsinki Univ., Helsinki (Finland). Dept. of Plant Biology

    1995-12-31

    Photosynthesis is often among the first targets of the air pollution stress of plants. As chlorophyll fluorescence is a process competing with photosynthetic electron transport it can be employed to study the potential photosynthetic capacity and to detect damage to the photosynthetic apparatus. Many previous studies have shown that chlorophyll fluorescence can be a powerful tool in the detection of forest damage. In this preliminary study, singular value analysis of the fluorescence induction curves was used together with the traditional way of analyzing fluorescence measurements. The experimental data were collected from ozone and carbon dioxide fumigated Scots pine saplings. (author)

  11. Early Water Stress Detection Using Leaf-Level Measurements of Chlorophyll Fluorescence and Temperature Data

    Directory of Open Access Journals (Sweden)

    Zhuoya Ni

    2015-03-01

    Full Text Available The purpose of this paper was to investigate the early water stress in maize using leaf-level measurements of chlorophyll fluorescence and temperature. In this study, a series of diurnal measurements, such as leaf chlorophyll fluorescence (Fs, leaf spectrum, temperature and photosynthetically active radiation (PAR, were conducted for maize during gradient watering and filled watering experiments. Fraunhofer Line Discriminator methods (FLD and 3FLD were used to obtain fluorescence from leaves spectrum. This simulated work using the SCOPE model demonstrated the variations in fluorescence and temperature in stress levels expressed by different stress factors. In the field measurement, the gradient experiment revealed that chlorophyll fluorescence decreased for plants with water stress relative to well-water plants and Tleaf-Tair increased; the filled watering experiment stated that chlorophyll fluorescence of maize under water stress were similar to those of maize under well-watering condition. In addition, the relationships between the Fs, retrieved fluorescence, Tleaf-Tair and water content were analyzed. The Fs determination resulted to the best coefficients of determination for the normalized retrieved fluorescence FLD/PAR (R2 = 0.54, Tleaf-Tair (R2 = 0.48 and water content (R2 = 0.71. The normalized retrieved fluorescence yielded a good coefficient of determination for Tleaf-Tair (R2 = 0.48. This study demonstrated that chlorophyll fluorescence could reflect variations in the physiological states of plants during early water stress, and leaf temperature confirmed the chlorophyll fluorescence analysis results and improved the accuracy of the water stress detection.

  12. Measurements of Solar Induced Chlorophyll Fluorescence at 685 nm by Airborne Plant Fluorescence Sensor (APFS)

    Science.gov (United States)

    Morgan, F.; Yee, J. H.; Boldt, J.; Cook, W. B.; Corp, L. A.

    2015-12-01

    Solar-induced chlorophyll fluorescence (ChlF) by terrestrial vegetation is linked closely to photosynthetic efficiency that can be exploited to monitor the plant health status and to assess the terrestrial carbon budget from space. The weak, broad continuum ChlF signal can be detected from the fill-in of strong O2 absorption lines or solar Fraunhofer lines in the reflected spectral radiation. The Johns Hopkins University, Applied Physics Laboratory (JHU/APL) Airborne Plant Fluorescence Sensor (APFS) is a triple etalon Fabry-Perot interferometer designed and optimized specifically for the ChlF sensing from an airborne platform using this line fill-in technique. In this paper, we will present the results of APFS ChlF measurements obtained from a NASA Langley King Air during two airborne campaigns (12/12 in 2014 and 5/20 in 2015) over various land, river, and vegetated targets in Virginia during stressed and growth seasons.

  13. Effects of Anaerobiosis on Chlorophyll Fluorescence Yield in Spinach (Spinacia oleracea) Leaf Discs.

    Science.gov (United States)

    Harris, G. C.; Heber, U.

    1993-01-01

    When spinach (Spinacia oleracea) leaf discs were incubated in a dark anaerobic environment, the chlorophyll fluorescence yield was much increased relative to the aerobic control. Occasionally, the fluorescence yield of the darkened anaerobic samples approached 80% of the maximum fluorescence. The anaerobic incubation period also induced in a leaf disc the capacity to exhibit a low light-mediated chlorophyll fluorescence induction phenomenon. This involved a rapid and slow increase in fluorescence yield, followed by a slow quenching. This could be induced by light levels as low as 400 [mu]W m-2. The anaerobic-dependent increase in chlorophyll fluorescence yield could be relaxed by either far-red light, O2, or a saturating pulse of white light. It was concluded that the anaerobic-dependent increase in chlorophyll fluorescence yield was due to a dark reduction of the plastoquinone pool and its relaxation by reoxidation. Darkened isolated chloroplasts did not exhibit a fluorescence yield increase under anaerobic conditions. Fluorescence slowly increased only when dithiothreitol or dithionite was added. PMID:12231769

  14. Towards a merged satellite and in situ fluorescence ocean chlorophyll product

    Science.gov (United States)

    Lavigne, H.; D'Ortenzio, F.; Claustre, H.; Poteau, A.

    2012-06-01

    Understanding the ocean carbon cycle requires a precise assessment of phytoplankton biomass in the oceans. In terms of numbers of observations, satellite data represent the largest available data set. However, as they are limited to surface waters, they have to be merged with in situ observations. Amongst the in situ data, fluorescence profiles constitute the greatest data set available, because fluorometers have operated routinely on oceanographic cruises since the 1970s. Nevertheless, fluorescence is only a proxy of the total chlorophyll a concentration and a data calibration is required. Calibration issues are, however, sources of uncertainty, and they have prevented a systematic and wide range exploitation of the fluorescence data set. In particular, very few attempts to standardize the fluorescence databases have been made. Consequently, merged estimations with other data sources (e.g. satellite) are lacking. We propose a merging method to fill this gap. It consists firstly in adjusting the fluorescence profile to impose a zero chlorophyll a concentration at depth. Secondly, each point of the fluorescence profile is then multiplied by a correction coefficient, which forces the chlorophyll a integrated content measured on the fluorescence profile to be consistent with the concomitant ocean colour observation. The method is close to the approach proposed by Boss et al. (2008) to correct fluorescence data of a profiling float, although important differences do exist. To develop and test our approach, in situ data from three open ocean stations (BATS, HOT and DYFAMED) were used. Comparison of the so-called "satellite-corrected" fluorescence profiles with concomitant bottle-derived estimations of chlorophyll a concentration was performed to evaluate the final error (estimated at 31%). Comparison with the Boss et al. (2008) method, using a subset of the DYFAMED data set, demonstrated that the methods have similar accuracy. The method was applied to two different

  15. Chlorophyll fluorescence emission as a reporter on cold tolerance in Arabidopsis thaliana accessions.

    Science.gov (United States)

    Mishra, Anamika; Mishra, Kumud B; Höermiller, Imke I; Heyer, Arnd G; Nedbal, Ladislav

    2011-02-01

    Non-invasive, high-throughput screening methods are valuable tools in breeding for abiotic stress tolerance in plants. Optical signals such as chlorophyll fluorescence emission can be instrumental in developing new screening techniques. In order to examine the potential of chlorophyll fluorescence to reveal plant tolerance to low temperatures, we used a collection of nine Arabidopsis thaliana accessions and compared their fluorescence features with cold tolerance quantified by the well established electrolyte leakage method on detached leaves. We found that, during progressive cooling, the minimal chlorophyll fluorescence emission rose strongly and that this rise was highly dependent on the cold tolerance of the accessions. Maximum quantum yield of PSII photochemistry and steady state fluorescence normalized to minimal fluorescence were also highly correlated to the cold tolerance measured by the electrolyte leakage method. In order to further increase the capacity of the fluorescence detection to reveal the low temperature tolerance, we applied combinatorial imaging that employs plant classification based on multiple fluorescence features. We found that this method, by including the resolving power of several fluorescence features, can be well employed to detect cold tolerance already at mild sub-zero temperatures. Therefore, there is no need to freeze the screened plants to the largely damaging temperatures of around -15°C. This, together with the method's easy applicability, represents a major advantage of the fluorescence technique over the conventional electrolyte leakage method. 

  16. Two-photon excited fluorescence from higher electronic states of chlorophylls in photosynthetic antenna complexes a new approach to detect strong excitonic chlorophyll a/b coupling

    CERN Document Server

    Leupold, D; Ehlert, J; Irrgang, K D; Renger, G; Lokstein, H

    2002-01-01

    Stepwise two-photon excitation of chlorophyll a and b in the higher plant main light-harvesting complex (LHC II) and the minor complex CP29 (as well as in organic solution) with 100-fs pulses in the Q/sub y/ region results in a weak blue fluorescence. The dependence of the spectral shape of the blue fluorescence on excitation wavelength offers a new approach to elucidate the long-standing problem of the origin of spectral "chlorophyll forms" in pigment-protein complexes, in particular the characterization of chlorophyll a/b-heterodimers. As a first result we present evidence for the existence of strong chlorophyll a/b-interactions (excitonically coupled transitions at 650 and 680 nm) in LHC II at ambient temperature. In comparison with LHC II, the experiments with CP29 provide further evidence that the lowest energy chlorophyll a transition (at ~680 nm) is not excitonically coupled to chlorophyll b. (22 refs).

  17. Changes in photosynthetic pigments and chlorophyll-a fluorescence attributes of sweet-forage and grain sorghum cultivars under salt stress

    National Research Council Canada - National Science Library

    Sayyad-Amin, Parvaneh; Jahansooz, Mohammad-Reza; Borzouei, Azam; Ajili, Fatemeh

    2016-01-01

    .... To study salinity effects on photosynthetic pigment attributes including the chlorophyll content and chlorophyll fluorescence, an experiment was performed in a climate-controlled greenhouse at two...

  18. Concentration Effect on Quenching of Chlorophyll a Fluorescence by All-Trans-β-Carotene in Photosynthesis

    Directory of Open Access Journals (Sweden)

    Chen Chen

    2017-09-01

    Full Text Available Absorption, fluorescence spectra of chlorophyll a (Chl-a and all-trans-β-carotene (β-Car mixing solution are investigated in different polarity and polarizability solvents. The carotenoids regulate the energy flow in photosynthesis by interaction with chlorophyll, leading to an observable reduction of Chl-a fluorescence. The fluorescence red shifts with the increasing solvent polarizability. The energy transfer in the Chl-a and β-Car system is proposed. The electron transfer should be dominant in quenching Chl-a fluorescence rather than the energy transfer in this system. Polar solvent with large polarizability shows high quenching efficiency. When dissolved in carbon tetrachloride, Chl-a presents red shift of absorption and blue shift of fluorescence spectra with increasing β-Car concentration, which implies a Chl-a conformational change.

  19. Behavior of Sethoxydim Alone or in Combination with Turnip Oils on Chlorophyll Fluorescence Parameter

    Directory of Open Access Journals (Sweden)

    Hossein HAMMAMI

    2014-03-01

    Full Text Available Sethoxydim is an acetyl-coenzyme A carboxylase (ACCase inhibitor that changed the shape of the chlorophyll fluorescence curve (kautsky curve in wild oat (Avena ludoviciana Durieu. in greenhouse experiment. This experiment was conducted as completely randomized factorial design with three replications at the College of Agriculture, Ferdowsi University of Mashhad, Iran, during 2012. Results of this study revealed that sethoxydim only and plus emulsifiable turnip oil changed the shape of the chlorophyll fluorescence curve (kautsky curve 7 days after spraying. Sethoxydim plus emulsifiable turnip oil changed the shape of the kautsky curve more than for sethoxydim only. We found that in our study the fv/fm (maximum quantum efficiency was closely linked to the fresh and dry weight dose-response. Sethoxydim plus emulsifiable turnip oil proved more rapidly effect on fv/fm in comparison with sethoxydim only. The fresh and dry weight dose-response relationship with fv/fm showed a similar behavior. This study revealed a good relation between fresh and dry weight according with values of 28 DAS and fv/fm 7 DAS. In general, the findings of this study revealed that Fv/Fm is a good parameter for evaluating effect of sethoxydim little time after spraying. Also, this research showed that 4 folds more time for classical screening methods comparing to chlorophyll fluorescence method. Thereupon, classical screening methods may be replaced by chlorophyll fluorescence method in future.

  20. Phenotyping of wheat cultivars for heat tolerance using chlorophyll a fluorescence

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto

    2012-01-01

    with an increased genetic component (15.43.6%), which was further increased to 27.96.8% in the third screening with 41 contrasting cultivars. This contrasting set of cultivars was then used to compare the ability of chlorophyll fluorescence parameters to detect genetic difference in heat tolerance...

  1. Chlorophyll fluorescence and X-ray analyses to characterise and improve paddy rice seed quality

    NARCIS (Netherlands)

    Costa, D.S.; Kodde, J.; Groot, S.P.C.

    2014-01-01

    The presence of less-mature seeds or seeds with cracks in a paddy rice seed lot may result in lower seed quality. The potential of chlorophyll fluorescence to provide information on the maturity of single seeds and X-ray analyses to identify seeds with cracks was evaluated in relation to paddy rice

  2. Simulations of chlorophyll fluorescence incorporated into the Community Land Model version 4

    NARCIS (Netherlands)

    Lee, J.E.; Berry, J.A.; van der Tol, C.; Yang, X.; Guanter, L.; Damm, A.; Baker, I.; Frankenberg, C.

    2015-01-01

    Several studies have shown that satellite retrievals of solar-induced chlorophyll fluorescence (SIF) provide useful information on terrestrial photosynthesis or gross primary production (GPP). Here, we have incorporated equations coupling SIF to photosynthesis in a land surface model, the National

  3. SmartFluo: A Method and Affordable Adapter to Measure Chlorophyll a Fluorescence with Smartphones

    NARCIS (Netherlands)

    Friedrichs, Anna; Busch, Julia; van der Woerd, H.J.; Zielinski, Oliver

    2017-01-01

    In order to increase the monitoring capabilities of inland and coastal waters, there is a need for new, affordable, sensitive and mobile instruments that could be operated semi-automatically in the field. This paper presents a prototype device to measure chlorophyll a fluorescence: the SmartFluo.

  4. Deriving sun-induced chlorophyll fluorescence from airborne based spectrometer data

    NARCIS (Netherlands)

    Damm, A.; Schickling, A.; Schlapfer, D.; Schaepman, M.E.; Rascher, U.

    2010-01-01

    Sun-induced chlorophyll fluorescence (Fs) is a promising parameter for remote measuring plant photosynthesis. It has been demonstrated that Fs at cell and leaf level is strongly related to photosynthesis. The transfer of the Fs approach to canopy level remains challenging as the canopy Fs signal is

  5. Metal-Enhanced Fluorescence of Chlorophylls in Light-Harvesting Complexes Coupled to Silver Nanowires

    Directory of Open Access Journals (Sweden)

    Dorota Kowalska

    2013-01-01

    Full Text Available We investigate metal-enhanced fluorescence of peridinin-chlorophyll protein coupled to silver nanowires using optical microscopy combined with spectrally and time-resolved fluorescence techniques. In particular we study two different sample geometries: first, in which the light-harvesting complexes are deposited onto silver nanowires, and second, where solution of both nanostructures are mixed prior deposition on a substrate. The results indicate that for the peridinin-chlorophyll complexes placed in the vicinity of the silver nanowires we observe higher intensities of fluorescence emission as compared to the reference sample, where no nanowires are present. Enhancement factors estimated for the sample where the light-harvesting complexes are mixed together with the silver nanowires prior deposition on a substrate are generally larger in comparison to the other geometry of a hybrid nanostructure. While fluorescence spectra are identical both in terms of overall shape and maximum wavelength for peridinin-chlorophyll-protein complexes both isolated and coupled to metallic nanostructures, we conclude that interaction with plasmon excitations in the latter remains neutral to the functionality of the biological system. Fluorescence transients measured for the PCP complexes coupled to the silver nanowires indicate shortening of the fluorescence lifetime pointing towards modifications of radiative rate due to plasmonic interactions. Our results can be applied for developing ways to plasmonically control the light-harvesting capability of photosynthetic complexes.

  6. Plant response to destruxins visualized by imaging of chlorophyll fluorescence

    Czech Academy of Sciences Publication Activity Database

    Soukupová, Julie; Smatanová, Sylvie; Nedbal, Ladislav; Jegorov, A.

    2003-01-01

    Roč. 118, č. 118 (2003), s. 399-405 ISSN 0031-9317 Institutional research plan: CEZ:MSM 123100001; CEZ:AV0Z6087904 Keywords : fungal infection, destruxins * fluorescence imaging Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 1.767, year: 2003

  7. Using chlorophyll fluorescence to determine stress in Eucalyptus ...

    African Journals Online (AJOL)

    A pilot trial was conducted to determine the effect of light, water and nutrient stress on the fluorescence emission of Eucalyptus grandis seedlings. Flourescence measurements were made on potted plants with a Hansatech Plant Efficiency Analyser, every one to two days from stress initiation until trial termination. The results ...

  8. Difference in oxidative stress tolerance between rice cultivars estimated with chlorophyll fluorescence analysis.

    Science.gov (United States)

    Kasajima, Ichiro

    2017-04-26

    Oxidative stress is considered to be involved in growth retardation of plants when they are exposed to a variety of biotic and abiotic stresses. Despite its potential importance in improving crop production, comparative studies on oxidative stress tolerance between rice (Oryza sativa L.) cultivars are limited. This work describes the difference in term of oxidative stress tolerance between 72 rice cultivars. 72 rice cultivars grown under naturally lit greenhouse were used in this study. Excised leaf discs were subjected to a low concentration of methyl viologen (paraquat), a chemical reagent known to generate reactive oxygen species in chloroplast. Chlorophyll fluorescence analysis using a two-dimensional fluorescence meter, ion leakage analysis as well as the measurement of chlorophyll contents were used to evaluate the oxidative stress tolerance of leaf discs. Furthermore, fluorescence intensities were finely analyzed based on new fluorescence theories that we have optimized. Treatment of leaf discs with methyl viologen caused differential decrease of maximum quantum yield of photosystem II (Fv/Fm) between cultivars. Decrease of Fv/Fm was also closely correlated with increase of ion leakage and decrease of chlorophyll a/b ratio. Fv/Fm was factorized into photochemical and non-photochemical parameters to classify rice cultivars into sensitive and tolerant ones. Among the 72 compared rice cultivars, the traditional cultivar Co13 was identified as the most tolerant to oxidative stress. Koshihikari, a dominant modern Japonica cultivar in Japan as well as IR58, one of the modern Indica breeding lines exhibited a strong tolerance to oxidative stress. Close correlation between Fv/Fm and chlorophyll a/b ratio provides a simple method to estimate oxidative stress tolerance, without measurement of chlorophyll fluorescence with special equipment. The fact that modern cultivars, especially major cultivars possessed tolerance to oxidative stress suggests that oxidative stress

  9. Chlorophyll fluorescence analysis: a guide to good practice and understanding some new applications.

    Science.gov (United States)

    Murchie, E H; Lawson, T

    2013-10-01

    Chlorophyll fluorescence is a non-invasive measurement of photosystem II (PSII) activity and is a commonly used technique in plant physiology. The sensitivity of PSII activity to abiotic and biotic factors has made this a key technique not only for understanding the photosynthetic mechanisms but also as a broader indicator of how plants respond to environmental change. This, along with low cost and ease of collecting data, has resulted in the appearance of a large array of instrument types for measurement and calculated parameters which can be bewildering for the new user. Moreover, its accessibility can lead to misuse and misinterpretation when the underlying photosynthetic processes are not fully appreciated. This review is timely because it sits at a point of renewed interest in chlorophyll fluorescence where fast measurements of photosynthetic performance are now required for crop improvement purposes. Here we help the researcher make choices in terms of protocols using the equipment and expertise available, especially for field measurements. We start with a basic overview of the principles of fluorescence analysis and provide advice on best practice for taking pulse amplitude-modulated measurements. We also discuss a number of emerging techniques for contemporary crop and ecology research, where we see continual development and application of analytical techniques to meet the new challenges that have arisen in recent years. We end the review by briefly discussing the emerging area of monitoring fluorescence, chlorophyll fluorescence imaging, field phenotyping, and remote sensing of crops for yield and biomass enhancement.

  10. Towards a merged satellite and in situ fluorescence ocean chlorophyll product

    Directory of Open Access Journals (Sweden)

    H. Lavigne

    2012-06-01

    Full Text Available Understanding the ocean carbon cycle requires a precise assessment of phytoplankton biomass in the oceans. In terms of numbers of observations, satellite data represent the largest available data set. However, as they are limited to surface waters, they have to be merged with in situ observations. Amongst the in situ data, fluorescence profiles constitute the greatest data set available, because fluorometers have operated routinely on oceanographic cruises since the 1970s. Nevertheless, fluorescence is only a proxy of the total chlorophyll a concentration and a data calibration is required. Calibration issues are, however, sources of uncertainty, and they have prevented a systematic and wide range exploitation of the fluorescence data set. In particular, very few attempts to standardize the fluorescence databases have been made. Consequently, merged estimations with other data sources (e.g. satellite are lacking.

    We propose a merging method to fill this gap. It consists firstly in adjusting the fluorescence profile to impose a zero chlorophyll a concentration at depth. Secondly, each point of the fluorescence profile is then multiplied by a correction coefficient, which forces the chlorophyll a integrated content measured on the fluorescence profile to be consistent with the concomitant ocean colour observation. The method is close to the approach proposed by Boss et al. (2008 to correct fluorescence data of a profiling float, although important differences do exist. To develop and test our approach, in situ data from three open ocean stations (BATS, HOT and DYFAMED were used. Comparison of the so-called "satellite-corrected" fluorescence profiles with concomitant bottle-derived estimations of chlorophyll a concentration was performed to evaluate the final error (estimated at 31%. Comparison with the Boss et al. (2008 method, using a subset of the DYFAMED data set, demonstrated that the methods have similar

  11. Computer Reconstruction of Plant Growth and Chlorophyll Fluorescence Emission in Three Spatial Dimensions

    Directory of Open Access Journals (Sweden)

    Ladislav Nedbal

    2012-01-01

    Full Text Available Plant leaves grow and change their orientation as well their emission of chlorophyll fluorescence in time. All these dynamic plant properties can be semi-automatically monitored by a 3D imaging system that generates plant models by the method of coded light illumination, fluorescence imaging and computer 3D reconstruction. Here, we describe the essentials of the method, as well as the system hardware. We show that the technique can reconstruct, with a high fidelity, the leaf size, the leaf angle and the plant height. The method fails with wilted plants when leaves overlap obscuring their true area. This effect, naturally, also interferes when the method is applied to measure plant growth under water stress. The method is, however, very potent in capturing the plant dynamics under mild stress and without stress. The 3D reconstruction is also highly effective in correcting geometrical factors that distort measurements of chlorophyll fluorescence emission of naturally positioned plant leaves.

  12. Estimating chlorophyll content and photochemical yield of photosystem II (ΦPSII) using solar-induced chlorophyll fluorescence measurements at different growing stages of attached leaves

    OpenAIRE

    Tubuxin, Bayaer; Rahimzadeh-Bajgiran, Parinaz; Ginnan, Yusaku; Hosoi, Fumiki; Omasa, Kenji

    2015-01-01

    This paper illustrates the possibility of measuring chlorophyll (Chl) content and Chl fluorescence parameters by the solar-induced Chl fluorescence (SIF) method using the Fraunhofer line depth (FLD) principle, and compares the results with the standard measurement methods. A high-spectral resolution HR2000+ and an ordinary USB4000 spectrometer were used to measure leaf reflectance under solar and artificial light, respectively, to estimate Chl fluorescence. Using leaves of Capsicum annuum cv....

  13. Chlorophyll and Nutrient Data - Ocean Survival of Salmonids

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A study to evaluate the role of changing ocean conditions on growth and survival of juvenile salmon from the Columbia River basin as they enter the Columbia River...

  14. Chlorophyll induced fluorescence retrieved from GOME2 for improving gross primary productivity estimates of vegetation

    Science.gov (United States)

    van Leth, Thomas C.; Verstraeten, Willem W.; Sanders, Abram F. J.

    2014-05-01

    Mapping terrestrial chlorophyll fluorescence is a crucial activity to obtain information on the functional status of vegetation and to improve estimates of light-use efficiency (LUE) and global primary productivity (GPP). GPP quantifies carbon fixation by plant ecosystems and is therefore an important parameter for budgeting terrestrial carbon cycles. Satellite remote sensing offers an excellent tool for investigating GPP in a spatially explicit fashion across different scales of observation. The GPP estimates, however, still remain largely uncertain due to biotic and abiotic factors that influence plant production. Sun-induced fluorescence has the ability to enhance our knowledge on how environmentally induced changes affect the LUE. This can be linked to optical derived remote sensing parameters thereby reducing the uncertainty in GPP estimates. Satellite measurements provide a relatively new perspective on global sun-induced fluorescence, enabling us to quantify spatial distributions and changes over time. Techniques have recently been developed to retrieve fluorescence emissions from hyperspectral satellite measurements. We use data from the Global Ozone Monitoring Instrument 2 (GOME2) to infer terrestrial fluorescence. The spectral signatures of three basic components atmospheric: absorption, surface reflectance, and fluorescence radiance are separated using reference measurements of non-fluorescent surfaces (desserts, deep oceans and ice) to solve for the atmospheric absorption. An empirically based principal component analysis (PCA) approach is applied similar to that of Joiner et al. (2013, ACP). Here we show our first global maps of the GOME2 retrievals of chlorophyll fluorescence. First results indicate fluorescence distributions that are similar with that obtained by GOSAT and GOME2 as reported by Joiner et al. (2013, ACP), although we find slightly higher values. In view of optimizing the fluorescence retrieval, we will show the effect of the references

  15. Plant abiotic stress diagnostic by laser induced chlorophyll fluorescence spectral analysis of in vivo leaf tissue of biofuel species

    Science.gov (United States)

    Gouveia-Neto, Artur S.; Silva, Elias A., Jr.; Costa, Ernande B.; Bueno, Luciano A.; Silva, Luciana M. H.; Granja, Manuela M. C.; Medeiros, Maria J. L.; Câmara, Terezinha J. R.; Willadino, Lilia G.

    2010-02-01

    Laser induced fluorescence is exploited to evaluate the effect of abiotic stresses upon the evolution and characteristics of in vivo chlorophyll emission spectra of leaves tissues of brazilian biofuel plants species(Saccharum officinarum and Jatropha curcas). The chlorophyll fluorescence spectra of 20 min predarkened intact leaves were studied employing several excitation wavelengths in the UV-VIS spectral region. Red(Fr) and far-red (FFr) chlorophyll fluorescence emission signals around 685 nm and 735 nm, respectively, were analyzed as a function of the stress intensity and the time of illumination(Kautsky effect). The Chl fluorescence ratio Fr/FFr which is a valuable nondestructive indicator of the chlorophyll content of leaves was investigated during a period of time of 30 days. The dependence of the Chl fluorescence ratio Fr/FFr upon the intensity of the abiotic stress(salinity) was examined. The results indicated that the salinity plays a major hole in the chlorophyll concentration of leaves in both plants spieces, with a significant reduction in the chlorophyll content for NaCl concentrations in the 25 - 200 mM range. The laser induced chlorophyll fluorescence analysis allowed detection of damage caused by salinity in the early stages of the plants growing process, and can be used as an early-warning indicator of salinity stress

  16. Advances in Remote Sensing of Vegetation Merging NDVI, Soil Moisture, and Chlorophyll Fluorescence

    Science.gov (United States)

    Tucker, Compton

    2016-04-01

    I will describe an advance in remote sensing of vegetation in the time domain that combines simultaneous measurements of the normalized difference vegetation index, soil moisture, and chlorophyll fluorescence, all from different satellite sensors but acquired for the same areas at the same time step. The different sensor data are MODIS NDVI data from both Terra and Aqua platforms, soil moisture data from SMOS & SMP (aka SMAP but with only the passive radiometer), and chlorophyll fluorescence data from GOME-2. The complementary combination of these data provide important crop yield information for agricultural production estimates at critical phenological times in the growing season, provide a scientific basis to map land degradation, and enable quantitative determination of the end of the growing season in temperate zones.

  17. Lifetime of fluorescence from light-harvesting chlorophyll a/b proteins: excitation intensity dependence

    Energy Technology Data Exchange (ETDEWEB)

    Nordlund, T.M. (Univ. of Rochester, NY); Knox, W.H.

    1981-10-01

    The fluorescence from a purified, aggregate form of the light-harvesting chlorophyll a/b protein has a lifetime of 1.2 +/- 0.5 ns at low excitation intensity, but the lifetime decreases significantly when the intensity of the 20-ps, 5300nm excitation pulse is increased above about 10/sup 16/ photons/cm/sup 2/. A solubilized, monomeric form of the protein, on the other hand, has a fluorescence lifetime of 3.1 +/- 0.3 ns independent of excitation intensity from 10/sup 14/-10/sup 18/ photons/cm/sup 2//pulse. We interpret the lifetime shortening in the aggregates and the lack of shortening in monomers in terms of exciton annihilation, facilitated in the aggregate by the larger population of interacting chlorophylls.

  18. Engineered drought tolerance in tomato plants is reflected in chlorophyll fluorescence emission

    Czech Academy of Sciences Publication Activity Database

    Mishra, Kumud; Iannacone, R.; Petrozza, A.; Mishra, Anamika; Armentano, N.; La Vecchia, G.; Trtílek, M.; Cellini, F.; Nedbal, Ladislav

    2012-01-01

    Roč. 182, SI (2012), s. 79-86 ISSN 0168-9452 R&D Projects: GA MŠk OC08055; GA MŠk 2B06068; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Chlorophyll fluorescence * Drought * High-throughput screening * Solanum lycopersicum * Transcription factor * Transgenic plant Subject RIV: EH - Ecology, Behaviour Impact factor: 2.922, year: 2012

  19. Computer Reconstruction of Plant Growth and Chlorophyll Fluorescence Emission in Three Spatial Dimensions

    Czech Academy of Sciences Publication Activity Database

    Bellasio, Ch.; Olejníčková, Julie; Tesař, R.; Šebela, David; Nedbal, Ladislav

    2012-01-01

    Roč. 12, č. 1 (2012), s. 1052-1071 ISSN 1424-8220 R&D Projects: GA ČR GA522/09/1565; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : 3D reconstruction * chlorophyll fluorescence imaging * leaf area * leaf angle * plant growth * coded light Subject RIV: EH - Ecology, Behaviour Impact factor: 1.953, year: 2012

  20. THE USE OF CHLOROPHYLL FLUORESCENCE «a» FOR BIOTESTING OF THE AQUATIC ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    V. A. Osipov

    2012-01-01

    Full Text Available The impact on marine algae Thalassiosiraweisflogii, Pseudo-nitzshiadelicatissima of copper sulfate, chloride of mercury, methylmercury were studied. Found a sharp increase sensitivity FS 2 of microalgae cultures and natural phytoplankton to salts of heavy metals in the conditions of the light of the stress that is associated with inhibition of protein synthetic reactions. Conclusions are made about the prospects of the use of fluorescence of chlorophyll "a" for biotesting.

  1. Cold-Induced Sudden Reversible Lowering of in Vivo Chlorophyll Fluorescence after Saturating Light Pulses 1

    Science.gov (United States)

    Larcher, Walter; Neuner, Gilbert

    1989-01-01

    In chilling-sensitive plants (Glycine max, Saintpaulia ionantha, Saccharum officinarum) a sudden reversible drop in chlorophyll fluorescence occurs during photosynthetic induction immediately following saturating light pulses at low temperatures in the range 4 to 8°C. A comparison of two soybean cultivars of different chilling sensitivities revealed that this phenomenon, termed lowwave, indicates specific thresholds of low temperature stress. Its occurrence under controlled chilling can be regarded as a quantitative marker for screening chilling susceptibility in angiosperms. PMID:16666615

  2. Chlorophyll a Covalently Bonded to Organo-Modified Translucent Silica Xerogels: Optimizing Fluorescence and Maximum Loading

    Directory of Open Access Journals (Sweden)

    M. A. García-Sánchez

    2016-07-01

    Full Text Available Chlorophyll is a pyrrolic pigment with important optical properties, which is the reason it has been studied for many years. Recently, interest has been rising with respect to this molecule because of its outstanding physicochemical properties, particularly applicable to the design and development of luminescent materials, hybrid sensor systems, and photodynamic therapy devices for the treatment of cancer cells and bacteria. More recently, our research group has been finding evidence for the possibility of preserving these important properties of substrates containing chlorophyll covalently incorporated within solid pore matrices, such as SiO2, TiO2 or ZrO2 synthesized through the sol-gel process. In this work, we study the optical properties of silica xerogels organo-modified on their surface with allyl and phenyl groups and containing different concentrations of chlorophyll bonded to the pore walls, in order to optimize the fluorescence that these macrocyclic species displays in solution. The intention of this investigation was to determine the maximum chlorophyll a concentration at which this molecule can be trapped inside the pores of a given xerogel and to ascertain if this pigment remains trapped as a monomer, a dimer, or aggregate. Allyl and phenyl groups were deposited on the surface of xerogels in view of their important effects on the stability of the molecule, as well as over the fluorescence emission of chlorophyll; however, these organic groups allow the trapping of either chlorophyll a monomers or dimers. The determination of the above parameters allows finding the most adequate systems for subsequent in vitro or in vivo studies. The characterization of the obtained xerogels was performed through spectroscopic absorption, emission and excitation spectra. These hybrid systems can be employed as mimics of natural systems; the entrapment of chlorophyll inside pore matrices indicates that it is possible to exploit some of the most

  3. SmartFluo: A Method and Affordable Adapter to Measure Chlorophyll a Fluorescence with Smartphones.

    Science.gov (United States)

    Friedrichs, Anna; Busch, Julia Anke; van der Woerd, Hendrik Jan; Zielinski, Oliver

    2017-03-25

    In order to increase the monitoring capabilities of inland and coastal waters, there is a need for new, affordable, sensitive and mobile instruments that could be operated semi-automatically in the field. This paper presents a prototype device to measure chlorophyll a fluorescence: the SmartFluo. The device is a combination of a smartphone offering an intuitive operation interface and an adapter implying a cuvette holder, as well as a suitable illumination source. SmartFluo is based on stimulated fluorescence of water constituents such as chlorophyll a . The red band of the digital smartphone camera is sensitive enough to detect quantitatively the characteristic red fluorescence emission. The adapter contains a light source, a strong light emitting diode and additional filters to enhance the signal-to-noise ratio and to suppress the impact of scattering. A novel algorithm utilizing the red band of the camera is provided. Laboratory experiments of the SmartFluo show a linear correlation (R 2 = 0.98) to the chlorophyll a concentrations measured by reference instruments, such as a high-performance benchtop laboratory fluorometer (LS 55, PerkinElmer).

  4. Early Identification of Herbicide Stress in Soybean (Glycine max (L.) Merr.) Using Chlorophyll Fluorescence Imaging Technology.

    Science.gov (United States)

    Li, Hui; Wang, Pei; Weber, Jonas Felix; Gerhards, Roland

    2017-12-22

    Herbicides may damage soybean in conventional production systems. Chlorophyll fluorescence imaging technology has been applied to identify herbicide stress in weed species a few days after application. In this study, greenhouse experiments followed by field experiments at five sites were conducted to investigate if the chlorophyll fluorescence imaging is capable of identifying herbicide stress in soybean shortly after application. Measurements were carried out from emergence until the three-to-four-leaf stage of the soybean plants. Results showed that maximal photosystem II (PS II) quantum yield and shoot dry biomass was significantly reduced in soybean by herbicides compared to the untreated control plants. The stress of PS II inhibiting herbicides occurred on the cotyledons of soybean and plants recovered after one week. The stress induced by DOXP synthase-, microtubule assembly-, or cell division-inhibitors was measured from the two-leaf stage until four-leaf stage of soybean. We could demonstrate that the chlorophyll fluorescence imaging technology is capable for detecting herbicide stress in soybean. The system can be applied under both greenhouse and field conditions. This helps farmers to select weed control strategies with less phytotoxicity in soybean and avoid yield losses due to herbicide stress.

  5. Chlorophyll fluorescence imaging for the noninvasive assessment of anthocyanins in whole grape (Vitis vinifera L.) bunches.

    Science.gov (United States)

    Agati, Giovanni; Traversi, Maria Laura; Cerovic, Zoran G

    2008-01-01

    The distribution of anthocyanins in grape (Vitis vinifera L.) bunches from the Sangiovese cultivar was measured nondestructively by chlorophyll fluorescence imaging using two excitation light bands at 550 and 650 nm in sequence. The pixel intensity in the derived logarithm of the fluorescence excitation ratio image was directly related, by an exponential function (r2 = 0.93), to the anthocyanin concentration of berry extracts. The method will be useful for the assessment of the heterogeneity of anthocyanin accumulation in berries that is known to depend on physiologic and climatic factors. It can also represent a new, rapid and noninvasive technique for the assessment of grape ripening and the appropriate time of harvest.

  6. Effect of changes in chlorophyll concentration on photosynthetic properties I. Fluorescence and absorption of greening bean leaves

    NARCIS (Netherlands)

    Goedheer, J.C.

    1961-01-01

    In order to obtain new information about the way of functioning of chlorophyll in vivo a study was made of optical properties and photosynthesis under condition of a low chlorophyll content in the leave. It was found that the fluorescence yeild of greening bean leaves decreased from a value

  7. Effect of arsenic on reflectance spectra and chlorophyll fluorescence of aquatic plants.

    Science.gov (United States)

    Iriel, Analia; Dundas, Gavin; Fernández Cirelli, Alicia; Lagorio, Maria G

    2015-01-01

    Arsenic pollution of groundwater is a serious problem in many regions of Latin America that causes severe risks to human health. As a consequence, non-destructive monitoring methodologies, sensitive to arsenic presence in the environment and able to perform a rapid screening of large polluted areas, are highly sought-after. Both chlorophyll - a fluorescence and reflectance of aquatic plants may be potential indicators to sense toxicity in water media. In this work, the effects of arsenic on the optical and photophysical properties of leaves of different aquatic plants (Vallisneria gigantea, Azolla filiculoides and Lemna minor) were evaluated. Reflectance spectra were recorded for the plant leaves from 300 to 2400 nm. The spectral distribution of the fluorescence was also studied and corrected for light re-absorption processes. Photosynthetic parameters (Fv/Fm and ΦPSII) were additionally calculated from the variable chlorophyll fluorescence recorded with a pulse amplitude modulated fluorometer. Fluorescence and reflectance properties for V. gigantea and A. filiculoides were sensitive to arsenic presence in contrast to the behaviour of L. minor. Observed changes in fluorescence spectra could be interpreted in terms of preferential damage in photosystem II. The quantum efficiency of photosystem II for the first two species was also affected, decreasing upon arsenic treatment. As a result of this research, V. gigantea and A. filiculoides were proposed as bioindicators of arsenic occurrence in aquatic media. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Correlation of electronic carotenoid-chlorophyll interactions and fluorescence quenching with the aggregation of native LHC II and chlorophyll deficient mutants

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Pen-Nan; Bode, Stefan [Technische Universitaet Braunschweig, Institute for Physical and Theoretical Chemistry, Department for Biophysical Chemistry, Hans-Sommer-Strasse 10, 38106 Braunschweig (Germany); Wilk, Laura [Max Planck Institute of Biophysics, Department of Structural Biology, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main (Germany); Hafi, Nour [Technische Universitaet Braunschweig, Institute for Physical and Theoretical Chemistry, Department for Biophysical Chemistry, Hans-Sommer-Strasse 10, 38106 Braunschweig (Germany); Walla, Peter J., E-mail: pwalla@gwdg.de [Technische Universitaet Braunschweig, Institute for Physical and Theoretical Chemistry, Department for Biophysical Chemistry, Hans-Sommer-Strasse 10, 38106 Braunschweig (Germany); Max Planck Institute for Biophysical Chemistry, Department of Spectroscopy and Photochemical Kinetics, Am Fassberg 11, 37077 Goettingen (Germany)

    2010-07-19

    The aggregation dependent correlation between fluorescence quenching and the electronic carotenoid-chlorophyll interactions, {phi}{sub Coupling}{sup Car S{sub 1}-Chl}, as measured by comparing chlorophyll fluorescence observed after two- and one-photon excitation, has been investigated using native LHC II samples as well as mutants lacking Chl 2 and Chl 13. For native LHC II the same linear correlation between {phi}{sub Coupling}{sup Car S{sub 1}-Chl} and the fluorescence quenching was observed as previously reported for the pH and Zea-dependent quenching of LHC II . In order to elucidate which carotenoid-chlorophyll pair might dominate this correlation we also investigated the mutants lacking Chl 2 and Chl 13. However, also with these mutants the same linear correlation as for native LHC II was observed. This provides indication that these two chlorophylls play only a minor role for the observed effects. Nevertheless, we also conclude that this does not exclude that their neighboured carotenoids, lutein 1 and neoxanthin, might interact electronically with other chlorophylls close by.

  9. Development of the spectrometric imaging apparatus of laser induced fluorescence from plants and estimation of chlorophyll contents of rice leaves; Laser reiki keiko sokutei sochi no kaihatsu to inehanai no chlorophyll ganryo no suitei

    Energy Technology Data Exchange (ETDEWEB)

    Nakaya, K.; Shoji, K.; Hanyu, H.

    1999-05-01

    Photosynthetic activity of plants is an important factor to assess the micrometeorological effect of plant canopy or to estimate the influence of circumstances such as water stress. Light illumination induces fluorescence from a leaf or suspension of chloroplasts. The red chlorophyll fluorescence had been used to determine the process of the electron transportation in photosynthetic reaction. The fluorescence source other than chlorophyll is not announced sufficiently, but is supposed to be useful to determine the contents of the substance corresponding to physiological response of plants. We developed a fluorescence imaging apparatus to observe spectrum and distribution of laser induced fluorescence from a leaf. Pulsed UV-laser (Nd:YAG) induced blue-green fluorescence and red chlorophyll fluorescence from a green leaf. The pulse modulated measuring light and CCD with image-intensifier (ICCD) enable to detect the fluorescence from plants under illumination. The laser induced fluorescence (LIF) spectra were investigated to estimate the chlorophyll contents in leaves of rice. During the greening course of dark grown etiolated rice leaves, chlorophyll contents were determined using the extraction of leaves and steady state LIF spectra were measured. As a result, the ratio of fluorescent intensity between blue-green and red peaks (F460/F740 and F510/F740) decreased in proportion to alteration of chlorophyll contents respectively. These fluorescence intensity ratios perform more precise estimation of higher chlorophyll contents of leaves than reported red chlorophyll fluorescence intensity ratio (F690/E740). (author)

  10. Sterile measurement on the characteristics of chlorophyll fluorescence in plantlets in vitro preserved under low temperature condition

    Science.gov (United States)

    Wu, Yanyou; Xing, Deke

    Micro-environment such as temperature influenced the growth and quality of plantlets in vitro. Chlorophyll fluorescence (ChlF) parameter is an important one for photosynthesis capacity in plant. The modulated chlorophyll fluorescence imaging system can be used for obtaining ChlF imaging and signal of plantlet in vitro because the container has light permeability. Therefore, the biological activity and growth condition of plantlet in vitro can be estimated by sterilely measuring the characteristics of chlorophyll fluorescence. This study determined the parameter of chlorophyll fluorescence in Orychophragmus violaceus plantlets in vitro preserved under different temperature levels (0, 4, and 8°C). The results showed that photosynthesis capacity in Orychophragmus violaceus plantlets in vitro preserved under 4°C condition were higher than that under 0°C or 8°C conditions. The plantlets in vitro preserved under 4°C condition maintained a high vitality to be subcultured.

  11. High temperature stress monitoring and detection using chlorophyll a fluorescence and infrared thermography in chrysanthemum (Dendranthema grandiflora)

    DEFF Research Database (Denmark)

    Wakjera, Eshetu Janka; Körner, Oliver; Rosenqvist, Eva

    2013-01-01

    (PSII) and stomatal conductance (gs). A combination of chlorophyll a fluorescence, gas exchange measurements and infrared thermography was applied using Chrysanthemum (Dendranthema grandiflora Tzvelev) cultivar ‘Coral Charm’ as a model species. Increasing temperature had a highly significant effect...

  12. [Effects of elevated atmospheric CO2 concentration on mung bean leaf photosynthesis and chlorophyll fluorescence parameters].

    Science.gov (United States)

    Hao, Xing-yu; Han, Xue; Li, Ping; Yang, Hong-bin; Lin, Er-da

    2011-10-01

    By using free air CO2 enrichment (FACE) system, a pot experiment under field condition was conducted to study the effects of elevated CO2 concentration (550 +/- 60 micromol mol(-1)) on the leaf photosynthesis and chlorophyll fluorescence parameters of mung bean. Comparing with the control (CO2 concentration averagely 389 +/- 40 micromol mol(-1)), elevated CO2 concentration increased the leaf intercellular CO2 concentration (Ci) and net photosynthesis rate (P(n)) at flowering and pod growth stage by 9.8% and 11.7%, decreased the stomatic conductance (G(s)) and transpiration rate (T(r)) by 32.0% and 24.6%, respectively, and increased the water use efficiency (WUE) by 83.5%. Elevated CO2 concentration had lesser effects on the minimal fluorescence (F0), maximal fluorescence (F(m)), variable fluorescence (F(v)), ratio of variable fluorescence to minimal fluorescence (F(v)/F0), and ratio of variable fluorescence to maximal fluorescence (F(v)/F(m)) at bud stage, but increased the F0 at pod filling stage by 19.1% and decreased the Fm, F(v), F(v)/F0, and F(v)/F(m) by 9.0%, 14.3%, 25.8% , and 6.2%, respectively. These results suggested that elevated CO2 concentration could damage the structure of leaf photosystem II and consequently decrease the leaf photosynthetic capacity in the late growth phase of mung bean.

  13. A comparative study of the photosynthetic capacity in two green tide macroalgae using chlorophyll fluorescence.

    Science.gov (United States)

    Wang, Ying; Qu, Tongfei; Zhao, Xinyu; Tang, Xianghai; Xiao, Hui; Tang, Xuexi

    2016-01-01

    Green tides have occurred in the Yellow Sea, China, every year from 2007 to 2015. The free-floating Ulva prolifera (Müller) J. Agardh was the causative macroalgal species. The co-occurring, attached U. intestinalis was also observed. Photosynthetic capacities were determined using chlorophyll fluorescence in situ and after 7 days lab acclimation, and a significant differences were noted. Pigment composition showed no obvious differences, but concentrations varied significantly, especially chlorophyll b in U. prolifera two times increase was observed after acclimation. The optimal photochemical efficiency of PS II (Fv/Fm) was significantly higher in U. prolifera. Photosynthetic rate (α), maximum relative electron transport rate (rETRmax), and minimum saturating irradiance (Ek), obtained from rapid light response curves (RLCs), showed almost the same photosynthetic physiological status as Fv/Fm. Quenching coefficients and low temperature (77 K) chlorophyll fluorescence emission spectra of thylakoid membranes analysis showed U. prolifera has a better recovery activity and plasticity of PSII than U. intestinalis. Furthermore, energy dissipation via non-photochemical quenching (NPQ) and state transitions showed efficacious photoprotection solution especially in U. prolifera suffered from the severe stresses. Results in the present study suggested that U. prolifera's higher photosynthetic capacity would contribute to its free-floating proliferation, and efficacious photoprotection in addition to favorable oceanographic conditions and high nutrient levels support its growth and aggregation.

  14. Establishment of integrated protocols for automated high throughput kinetic chlorophyll fluorescence analyses.

    Science.gov (United States)

    Tschiersch, Henning; Junker, Astrid; Meyer, Rhonda C; Altmann, Thomas

    2017-01-01

    Automated plant phenotyping has been established as a powerful new tool in studying plant growth, development and response to various types of biotic or abiotic stressors. Respective facilities mainly apply non-invasive imaging based methods, which enable the continuous quantification of the dynamics of plant growth and physiology during developmental progression. However, especially for plants of larger size, integrative, automated and high throughput measurements of complex physiological parameters such as photosystem II efficiency determined through kinetic chlorophyll fluorescence analysis remain a challenge. We present the technical installations and the establishment of experimental procedures that allow the integrated high throughput imaging of all commonly determined PSII parameters for small and large plants using kinetic chlorophyll fluorescence imaging systems (FluorCam, PSI) integrated into automated phenotyping facilities (Scanalyzer, LemnaTec). Besides determination of the maximum PSII efficiency, we focused on implementation of high throughput amenable protocols recording PSII operating efficiency (ΦPSII). Using the presented setup, this parameter is shown to be reproducibly measured in differently sized plants despite the corresponding variation in distance between plants and light source that caused small differences in incident light intensity. Values of ΦPSII obtained with the automated chlorophyll fluorescence imaging setup correlated very well with conventionally determined data using a spot-measuring chlorophyll fluorometer. The established high throughput operating protocols enable the screening of up to 1080 small and 184 large plants per hour, respectively. The application of the implemented high throughput protocols is demonstrated in screening experiments performed with large Arabidopsis and maize populations assessing natural variation in PSII efficiency. The incorporation of imaging systems suitable for kinetic chlorophyll

  15. Effects of electrolysis by low-amperage electric current on the chlorophyll fluorescence characteristics of Microcystis aeruginosa.

    Science.gov (United States)

    Lin, Li; Feng, Cong; Li, Qingyun; Wu, Min; Zhao, Liangyuan

    2015-10-01

    Effects of electrolysis by low-amperage electric current on the chlorophyll fluorescence characteristics of Microcystis aeruginosa were investigated in order to reveal the mechanisms of electrolytic inhibition of algae. Threshold of current density was found under a certain initial no. of algae cell. When current density was equal to or higher than the threshold (fixed electrolysis time), growth of algae was inhibited completely and the algae lost the ability to survive. Effect of algal solution volume on algal inhibition was insignificant. Thresholds of current density were 8, 10, 14, 20, and 22 mA cm(-2) at 2.5 × 10(7), 5 × 10(7), 1 × 10(8), 2.5 × 10(8), and 5 × 10(8) cells mL(-1) initial no. of algae cell, respectively. Correlativity between threshold of current and initial no. of algae cells was established for scale-up and determining operating conditions. Changes of chlorophyll fluorescence parameters demonstrated that photosystem (PS) II of algae was damaged by electrolysis but still maintained relatively high activity when algal solution was treated by current densities lower than the threshold. The activity of algae recovered completely after 6 days of cultivation. On the contrary, when current density was higher than the threshold, connection of phycobilisome (PBS) and PS II core complexes was destroyed, PS II system of algae was damaged irreversibly, and algae could not survive thoroughly. The inactivation of M. aeruginosa by electrolysis can be attributed to irreversible separation of PBS from PS II core complexes and the damage of PS II of M. aeruginosa.

  16. [Effects of acid rain stress on Eleocarpus glabripetalus seedlings leaf chlorophyll fluorescence characteristics and growth].

    Science.gov (United States)

    Yin, Xiu-Min; Yu, Shu-Quan; Jiang, Hong; Liu, Mei-Hu

    2010-06-01

    A pot experiment was conducted to study the Eleocarpus glabripetalus seedlings leaf chlorophyll fluorescence characteristics and growth in different seasons under simulated acid rain stress (heavy, pH = 2. 5; moderate, pH = 4.0; and control, pH = 5.6). In the same treatments, the leaf relative chlorophyll content (SPAD), maximum PS II photochemical efficiency (F(v)/F(m)), actual PSII photochemical quantum yield (phi(PS II)), plant height, and stem diameter in different seasons were all in the order of October > July > April > January. In the same seasons, all the parameters were in the order of heavy acid rain > moderate acid rain > control. The interactions between different acid rain stress and seasons showed significant effects on the SPAD, F(v)/F(m), plant height, and stem diameter, but lesser effects on phi(PS II), qp and qN.

  17. [Effects of simulated acid rain on Quercus glauca seedlings photosynthesis and chlorophyll fluorescence].

    Science.gov (United States)

    Li, Jia; Jiang, Hong; Yu, Shu-quan; Jiang, Fu-wei; Yin, Xiu-min; Lu, Mei-juan

    2009-09-01

    Taking the seedlings of Quercus glauca, a dominant evergreen broadleaf tree species in subtropical area, as test materials, this paper studied their photosynthesis, chlorophyll fluorescence, and chlorophyll content under effects of simulated acid rain with pH 2.5, 4.0, and 5.6 (CK). After 2-year acid rain stress, the net photosynthetic rate of Q. glauca increased significantly with decreasing pH of acid rain. The acid rain with pH 2.5 and 4.0 increased the stomatal conductance and transpiration rate, and the effect was more significant under pH 2.5. The intercellular CO2 concentration decreased in the order of pH 2.5 > pH 5.6 > pH 4.0. The maximum photosynthetic rate, light compensation point, light saturation point, and dark respiration rate were significantly higher under pH 2.5 and 4.0 than under pH 5.6, while the apparent quantum yield was not sensitive to acid rain stress. The maximal photochemical efficiency of PS II and the potential activity of PS II under pH 2.5 and 4.0 were significantly higher than those under pH 5.6. The relative chlorophyll content was in the order of pH 2.5 > pH 5.6 > pH 4.0, and there was a significant difference between pH 2.5 and 4.0. All the results suggested that the photosynthesis and chlorophyll fluorescence of Q. glauca increased under the effects of acid rain with pH 2.5 and 4.0, and the acid rain with pH 2.5 had more obvious effects.

  18. Leaf Gas Exchange and Chlorophyll a Fluorescence in Maize Leaves Infected with Stenocarpella macrospora.

    Science.gov (United States)

    Bermúdez-Cardona, Maria Bianney; Wordell Filho, João Américo; Rodrigues, Fabrício Ávila

    2015-01-01

    This study investigated the effect of macrospora leaf spot (MLS), caused by Stenocarpella macrospora, on photosynthetic gas exchange parameters and chlorophyll a fluorescence parameters determined in leaves of plants from two maize cultivars ('ECVSCS155' and 'HIB 32R48H') susceptible and highly susceptible, respectively, to S. macrospora. MLS severity was significantly lower in the leaves of plants from ECVSCS155 relative to the leaves of plants from HIB 32R48H. In both cultivars, net CO2 assimilation rate, stomatal conductance, and transpiration rate significantly decreased, while the internal to ambient CO2 concentration ratio increased in inoculated plants relative to noninoculated plants. The initial fluorescence and nonphotochemical quenching significantly increased in inoculated plants of ECVSCS155 and HIB 32R48H, respectively, relative to noninoculated plants. The maximum fluorescence, maximum PSII quantum efficiency, coefficient for photochemical quenching, and electron transport rate significantly decreased in inoculated plants relative to noninoculated plants. For both cultivars, concentrations of total chlorophyll (Chl) (a+b) and carotenoids and the Chl a/b ratio significantly decreased in inoculated plants relative to noninoculated plants. In conclusion, the results from the present study demonstrate, for the first time, that photosynthesis in the leaves of maize plants is dramatically affected during the infection process of S. macrospora, and impacts are primarily associated with limitations of a diffusive and biochemical nature.

  19. Differential heat sensitivity index in barley cultivars (Hordeum vulgare L.) monitored by chlorophyll a fluorescence OKJIP.

    Science.gov (United States)

    Oukarroum, Abdallah; El Madidi, Saïd; Strasser, Reto J

    2016-08-01

    The objective of this study was to differentiate the heat tolerance in ten varieties of barley (Hordeum vulgare L.) originating from Morocco. Five modern varieties and five landraces (local varieties) collected at five different geographical localities in the south of Morocco were investigated in the present study. After two weeks of growth, detached leaves were short term exposure to various temperatures (25, 30, 35, 40, and 45 °C) for 10 min in the dark. Two chlorophyll a fluorescence parameters derived from chlorophyll a fluorescence transient (OKJIP) (performance index (PIABS) and relative variable fluorescence at the K-step (VK)) were analysed. Heat treatment had a significant effect on the PIABS and VK at 45 °C treatment and the analysis of variance for PIABS and VK is highly significant between all varieties. The slope of the relationship between logPIABS and VK named heat sensitivity index (HSI) was used to evaluate the thermotolerance of photosystem II (PSII) between the studied barley varieties. According to this approach, barley varieties were screened and ranked for improving heat tolerance. HSI was found to be a new indicator with regard to distinguishing heat tolerance of different barley cultivars. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  20. Violet diode laser-induced chlorophyll fluorescence: a tool for assessing mosaic disease severity in cassava (Manihot esculenta Crantz) cultivars.

    Science.gov (United States)

    Anderson, Benjamin; Eghan, Moses J; Asare-Bediako, Elvis; Buah-Bassuah, Paul K

    2012-01-01

    Violet diode laser-induced chlorophyll fluorescence was used in agronomical assessment (disease severity and average yield per plant). Because cassava (Manihot esculenta Crantz) is of economic importance, improved cultivars with various levels of affinity for cassava mosaic disease were investigated. Fluorescence data correlated with cassava mosaic disease severity levels and with the average yield per plant.

  1. Evaluation of Copper Oxide Nanoparticles Toxicity Using Chlorophyll a Fluorescence Imaging in Lemna gibba

    Directory of Open Access Journals (Sweden)

    François Perreault

    2010-01-01

    Full Text Available Copper oxide nanoparticles (CuO NPs, used in antifouling paints of boats, are released in the environment and can induce toxicity to aquatic organisms. In this report, we used chlorophyll a fluorescence imaging to evaluate CuO NPs toxicity in Lemna gibba. This approach allowed to evaluate the differential effect of CuO NPs on photosynthesis of whole L. gibba plants. Exposure to 0.1 to 0.4 g/L CuO NPs during 48h induced strong inhibition of photosynthetic processes resulting in a decrease of plant growth. By using fluorescence imaging, different photosynthetic parameters were evaluated simultaneously in microplate conditions. Imaging of FO fluorescence yield showed the decrease of leaf photosynthetic active surface for whole plants exposed to CuO NPs. This method showed that CuO NPs inhibited photosystem II maximal, photosystem II operational quantum yields, and photochemical quenching of fluorescence associated with electron transport. Nonphotochemical fluorescence quenching as an indicator of energy dissipation not used in photosynthesis was shown to be increased by the effect of CuO NPs. Such approach in microplate conditions provides synchronous high repetition measurements for numerous plants. This study may give a reliable methodological approach to evaluate toxicity risk of NPs in aquatic ecosystems.

  2. Effect of carbon and nitrogen assimilation on chlorophyll fluorescence emission by the cyanobacterium Anacystis nidulans

    Energy Technology Data Exchange (ETDEWEB)

    Romero, J.M.; Lara, C. (Instituto de Bioquimica Vegetal y Fotosintesis, Univ. de Sevilla y CSIC, Sevilla (ES)); Sivak, M.N. (Dept. of Biochemistry, Michigan State Univ., East Lansing (US))

    1992-01-01

    O{sub 2} evolution and chlorophyll A fluorescence emission have been monitored in intact cells of the cyanobacterium Anacystis nidulans 1402-1 to study the influence of carbon and nitrogen assimilation on the operation of the photosynthetic apparatus. The pattern of fluorescence induction in dark-adapted cyanobacterial cells was different from that of higher plants. Cyanobacteria undergo large, rapid state transitions upon illumination, which lead to marked changes in the fluorescence yield, complicating the estimation of quenching coefficients. The Kautsky effect was not evident, although it could be masked by a state II-state I transition, upon illumination with actinic light. The use of inhibitors of carbon assimilation such as D,L-glyceraldehyde or iodoacetamide allowed us to relate changes in variable fluorescence to active CO{sub 2} fixation. Ammonium, but not nitrate, induced non-photochemical fluorescence quenching, in agreement with a previous report on green algae, indicative of an ammonium-induced state i transition. (au).

  3. Chlorophyll fluorescence tracks seasonal variations of photosynthesis from leaf to canopy in a temperate forest.

    Science.gov (United States)

    Yang, Hualei; Yang, Xi; Zhang, Yongguang; Heskel, Mary A; Lu, Xiaoliang; Munger, J William; Sun, Shucun; Tang, Jianwu

    2017-07-01

    Accurate estimation of terrestrial gross primary productivity (GPP) remains a challenge despite its importance in the global carbon cycle. Chlorophyll fluorescence (ChlF) has been recently adopted to understand photosynthesis and its response to the environment, particularly with remote sensing data. However, it remains unclear how ChlF and photosynthesis are linked at different spatial scales across the growing season. We examined seasonal relationships between ChlF and photosynthesis at the leaf, canopy, and ecosystem scales and explored how leaf-level ChlF was linked with canopy-scale solar-induced chlorophyll fluorescence (SIF) in a temperate deciduous forest at Harvard Forest, Massachusetts, USA. Our results show that ChlF captured the seasonal variations of photosynthesis with significant linear relationships between ChlF and photosynthesis across the growing season over different spatial scales (R2  = 0.73, 0.77, and 0.86 at leaf, canopy, and satellite scales, respectively; P < 0.0001). We developed a model to estimate GPP from the tower-based measurement of SIF and leaf-level ChlF parameters. The estimation of GPP from this model agreed well with flux tower observations of GPP (R2  = 0.68; P < 0.0001), demonstrating the potential of SIF for modeling GPP. At the leaf scale, we found that leaf Fq '/Fm ', the fraction of absorbed photons that are used for photochemistry for a light-adapted measurement from a pulse amplitude modulation fluorometer, was the best leaf fluorescence parameter to correlate with canopy SIF yield (SIF/APAR, R2  = 0.79; P < 0.0001). We also found that canopy SIF and SIF-derived GPP (GPPSIF ) were strongly correlated to leaf-level biochemistry and canopy structure, including chlorophyll content (R2  = 0.65 for canopy GPPSIF and chlorophyll content; P < 0.0001), leaf area index (LAI) (R2  = 0.35 for canopy GPPSIF and LAI; P < 0.0001), and normalized difference vegetation index (NDVI) (R2  = 0.36 for canopy GPPSIF

  4. Chlorophyll fluorescence: implementation in the full physics RemoTeC algorithm

    Science.gov (United States)

    Hahne, Philipp; Frankenberg, Christian; Hasekamp, Otto; Landgraf, Jochen; Butz, André

    2014-05-01

    Several operating and future satellite missions are dedicated to enhancing our understanding of the carbon cycle. They infer the atmospheric concentrations of carbon dioxide and methane from shortwave infrared absorption spectra of sunlight backscattered from Earth's atmosphere and surface. Exhibiting high spatial and temporal resolution, the inferred gas concentration databases provide valuable information for inverse modelling of source and sink processes at the Earth's surface. However, the inversion of sources and sinks requires highly accurate total column CO2 (XCO2) and CH4 (XCH4) measurements, which remains a challenge. Recently, Frankenberg et al., 2012, showed that - beside XCO2 and XCH4 - chlorophyll fluorescence can be retrieved from sounders such as GOSAT exploiting Fraunhofer lines in the vicinity of the O2 A-band. This has two implications: a) chlorophyll fluorescence itself being a proxy for photosynthetic activity yields new information on carbon cycle processes and b) the neglect of the fluorescence signal can induce errors in the retrieved greenhouse gas concentrations. Our RemoTeC full physics algorithm iteratively retrieves the target gas concentrations XCO2 and XCH4 along with atmospheric scattering properties and other auxiliary parameters. The radiative transfer model (RTM) LINTRAN provides RemoTeC with the single and multiple scattered intensity field and its analytically calculated derivatives. Here, we report on the implementation of a fluorescence light source at the lower boundary of our RTM. Processing three years of GOSAT data, we evaluate the performance of the refined retrieval method. To this end, we compare different retrieval configurations, using the s- and p-polarization detectors independently and combined, and validate to independent data sources.

  5. Hyperspectral solar-induced chlorophyll fluorescence of urban tree leaves: Analyses and applications

    Science.gov (United States)

    Van Wittenberghe, Shari

    Solar energy is the primary energy source for life on Earth which is converted into chemical energy through photosynthesis by plants, algae and cyanobacteria, releasing fuel for the organisms' activities. To dissipate excess of absorbed light energy, plants emit chlorophyll (Chl) fluorescence (650-850 nm) from the same location where photosynthesis takes place. Hence, it provides information on the efficiency of primary energy conversion. From this knowledge, many applications on vegetation and crop stress monitoring could be developed, a necessity for our planet under threat of a changing global climate. Even though the Chl fluorescence signal is weak against the intense reflected radiation background, methods for retrieving the solar-induced Chl fluorescence have been refined over the last years, both at leaf and airborne scale. However, a lack of studies on solar-induced Chl fluorescence gives difficulties for the interpretation of the signal. Within this thesis, hyperspectral upward and downward solar-induced Chl fluorescence is measured at leaf level. Fluorescence yield (FY) is calculated as well as different ratios characterizing the emitted Chl fluorescence shape. The research in this PhD dissertation illustrates the influence of several factors on the solar-induced Chl fluorescence signal. For instance, both the intensity of FY and its spectral shape of urban tree leaves are able to change under influence of stress factors such as traffic air pollution. This shows how solar-induced Chl fluorescence could function as an early stress indicator for vegetation. Further, it is shown that the signal contains information on the ultrastructure of the photosynthetic apparatus. Also, it is proven that the leaf anatomical structure and related light scattering properties play a role in the partitioning between upward and downward Chl fluorescence emission. All these findings indicate how the Chl fluorescence spectrum is influenced by factors which also influence

  6. Photosynthetic acclimation of Nannochloropsis oculata investigated by multi-wavelength chlorophyll fluorescence analysis.

    Science.gov (United States)

    Szabó, Milán; Parker, Kieran; Guruprasad, Supriya; Kuzhiumparambil, Unnikrishnan; Lilley, Ross McC; Tamburic, Bojan; Schliep, Martin; Larkum, Anthony W D; Schreiber, Ulrich; Raven, John A; Ralph, Peter J

    2014-09-01

    Multi-wavelength chlorophyll fluorescence analysis was utilised to examine the photosynthetic efficiency of the biofuel-producing alga Nannochloropsis oculata, grown under two light regimes; low (LL) and high (HL) irradiance levels. Wavelength dependency was evident in the functional absorption cross-section of Photosystem II (σII(λ)), absolute electron transfer rates (ETR(II)), and non-photochemical quenching (NPQ) of chlorophyll fluorescence in both HL and LL cells. While σII(λ) was not significantly different between the two growth conditions, HL cells upregulated ETR(II) 1.6-1.8-fold compared to LL cells, most significantly in the wavelength range of 440-540 nm. This indicates preferential utilisation of blue-green light, a highly relevant spectral region for visible light in algal pond conditions. Under these conditions, the HL cells accumulated saturated fatty acids, whereas polyunsaturated fatty acids were more abundant in LL cells. This knowledge is of importance for the use of N. oculata for fatty acid production in the biofuel industry. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Light use efficiency of terrestrial vegetation from remote sensing of chlorophyll fluorescence

    Science.gov (United States)

    Badgley, G. M.; Guan, K.; Berry, J. A.; Lobell, D. B.; Ryu, Y.

    2014-12-01

    Light use efficiency, the rate with which plants use absorbed photons to fix carbon dioxide, is a crucial parameter for estimating terrestrial carbon fluxes. Estimates of light use efficiency lie at the heart of how we model and understand ecosystem productivity. Here, we make use of the recent availability of high-resolution, multi-year records of remotely sensed measurements of chlorophyll fluorescence to refine estimates of light use efficiency in terrestrial ecosystems at the global scale. Directly estimating light use efficiency from remote sensing can help guide the current approach of constraining a theoretical maximum light use efficiency using meteorological data. We explore the usefulness of a derived light use efficiency at the global scale from remotely sensed records of chlorophyll fluorescence, photosynthetically active radiation, and canopy leaf area. Our estimates of light use efficiency show good agreement with light use efficiency calculated using Fluxtower data spanning several continents and a wide variety of ecosystems. We further benchmark our approach against the light use efficiency estimated from a variety of ecosystem models, such as BESS. Further refinement of our proposed technique promises to advance our ability to detect ecosystem stresses and further constrain our estimates of carbon fluxes within terrestrial ecosystems.

  8. A Method for Chlorophyll Fluorescence Imaging Control of the Vegetation under Microgravity Conditions

    Science.gov (United States)

    Krumov, A.; Vassilev, V.; Vassilev, N.

    term space exploration and flights. The goal is to provide a more natural environment on physiological, psychological and even esthetical levels for the astronauts. One of the important issues to be solved is development of methodologies and apparatus for continuous in-flight monitoring the biophysical status of the vegetation in order to assure it within the required physiological conditions. performed in the last years. There, applying qualitative observations and/or measurement of certain physiological parameters on different vegetation samples, the monitoring of the plant biostatus is done. These samples are prepared and characterized directly on board of the spacecraft, or are sent back to Earth, usually in a dried condition, for further investigation. In such a way, it is not possible to have a quick, real time control of the dynamics of the vegetation bioprocesses. When sudden plant stress condition appears, this can lead to a delayed and improper intervention by the operator and to irreversible changes in the physiological functions of the vegetation. A very promising approach for controlling the vegetation physiological processes and early detection of stress conditions is using the light induced chlorophyll fluorescence as an indicator for the plant biostatus. the registration of the intensity and the spatial distribution of the chlorophyll fluorescence, induced by a discrete spectrum light flux. The use of discontinuous spectrum is implied by the fact that the fluorescence irradiated by the vegetation is of much lower intensity than the one of the incident light. When the incident flux has a wide continuos spectrum, including the spectral bands of florescence, the latter is difficult to detect directly. We suggest to measure the fluorescence in bands of approximately 10nm width, centered at the maximum intensity fluorescence wave lengths, in which the spectrum of the incident light to be discontinued. These maxima of fluorescence are at 440nm and 520nm

  9. Leaf Gas Exchange and Chlorophyll a Fluorescence Imaging of Rice Leaves Infected with Monographella albescens.

    Science.gov (United States)

    Tatagiba, Sandro Dan; DaMatta, Fábio Murilo; Rodrigues, Fabrício Ávila

    2015-02-01

    This study was intended to analyze the photosynthetic performance of rice leaf blades infected with Monographella albescens by combining chlorophyll (Chl) a fluorescence images with gas exchange and photosynthetic pigment pools. The net CO2 assimilation rate, stomatal conductance, transpiration rate, total Chl and carotenoid pools, and Chl a/b ratio all decreased but the internal CO2 concentration increased in the inoculated plants compared with their noninoculated counterparts. The first detectable changes in the images of Chl a fluorescence from the leaves of inoculated plants were already evident at 24 h after inoculation (hai) and increased dramatically as the leaf scald lesions expanded. However, these changes were negligible for the photosystem II photochemical efficiency (Fv/Fm) at 24 hai, in contrast to other Chl fluorescence traits such as the photochemical quenching coefficient, yield of photochemistry, and yield for dissipation by downregulation; which, therefore, were much more sensitive than the Fv/Fm ratio in assessing the early stages of fungal infection. It was also demonstrated that M. albescens was able to impair the photosynthetic process in both symptomatic and asymptomatic leaf areas. Overall, it was proven that Chl a fluorescence imaging is an excellent tool to describe the loss of functionality of the photosynthetic apparatus occurring in rice leaves upon infection by M. albescens.

  10. Water deficit and salt stress diagnosis through LED induced chlorophyll fluorescence analysis in Jatropha curcas L. oil plants for biodiesel

    Science.gov (United States)

    Gouveia-Neto, Artur S.; Silva, Elias A., Jr.; Oliveira, Ronaldo A.; Cunha, Patrícia C.; Costa, Ernande B.; Câmara, Terezinha J. R.; Willadino, Lilia G.

    2011-02-01

    Light-emitting-diode induced chlorophyll fluorescence analysis is employed to investigate the effect of water and salt stress upon the growth process of physicnut(jatropha curcas) grain oil plants for biofuel. Red(Fr) and far-red (FFr) chlorophyll fluorescence emission signals around 685 nm and 735 nm, respectively, were observed and examined as a function of the stress intensity(salt concentration and water deficit) for a period of time of 30 days. The chlorophyll fluorescence(ChlF) ratio Fr/FFr which is a valuable nondestructive and nonintrusive indicator of the chlorophyll content of leaves was exploited to monitor the level of stress experienced by the jatropha plants. The ChlF technique data indicated that salinity plays a minor role in the chlorophyll concentration of leaves tissues for NaCl concentrations in the 25 to 200 mM range, and results agreed quite well with those obtained using conventional destructive spectrophotometric methods. Nevertheless, for higher NaCl concentrations a noticeable decrease in the Chl content was observed. The Chl fluorescence ratio analysis also permitted detection of damage caused by water deficit in the early stages of the plants growing process. A significant variation of the Fr/FFr ratio was observed sample in the first 10 days of the experiment when one compared control and nonwatered samples. The results suggest that the technique may potentially be applied as an early-warning indicator of stress caused by water deficit.

  11. Bridging the Gap from Leaf to Ecosystem Photosynthesis Using Chlorophyll Fluorescence

    Science.gov (United States)

    Paul-Limoges, E.; Hueni, A.; Damm, A.; Liebisch, F.; Schaepman, M. E.; Eugster, W.; Buchmann, N. C.

    2016-12-01

    Due to the large carbon (C) turnover between terrestrial ecosystems and the atmosphere, dynamics of photosynthesis can have significant effects on atmospheric CO2 concentrations and lead to large uncertainties in ecosystem C budgets. Eddy-covariance (EC) measurements give a detailed temporal record of CO2 fluxes at many Fluxnet locations worldwide; however, generalizations to larger regions are limited. In contrast, remote sensing (RS) allows estimating global C uptake rates, but lacks accuracy due to the generality of used proxies and the need for ground validations. New RS approaches using sun-induced chlorophyll fluorescence (SIF) hold the potential to directly assess ecosystem photosynthesis. However, many challenges remain linked to understanding the SIF signal. Our study aims to contribute linking these ground and airborne approaches to improve our understanding of photosynthesis at different scales using an innovative combination of hyperspectral RS, EC fluxes and leaf-level measurements. Two different ecosystems, mixed forest and cropland, with continuous EC measurements since 2004 were investigated. Overflights were performed with the high resolution imaging spectrometer APEX (Airborne Prism Experiment) at different times over eight years. Continuous tower-based hyperspectral measurements and monthly vertical profiles of leaf chlorophyll fluorescence, foliar pigment, C and N concentrations complemented the study in the last two years. Our results showed that dynamics in SIF and pigment concentrations were species-specific. Vertical differences in canopy photosynthesis were especially important during leaf growth and senescence. Different relationships between SIF and gross primary production were found for cropland and forest. By combining the strengths of ecophysiology, biometeorology and RS, this study will help improve our understanding of relationships between fluorescence and photosynthesis at different scales to obtain more accurate regional C

  12. High throughput quantitative phenotyping of plant resistance using chlorophyll fluorescence image analysis.

    Science.gov (United States)

    Rousseau, Céline; Belin, Etienne; Bove, Edouard; Rousseau, David; Fabre, Frédéric; Berruyer, Romain; Guillaumès, Jacky; Manceau, Charles; Jacques, Marie-Agnès; Boureau, Tristan

    2013-06-13

    In order to select for quantitative plant resistance to pathogens, high throughput approaches that can precisely quantify disease severity are needed. Automation and use of calibrated image analysis should provide more accurate, objective and faster analyses than visual assessments. In contrast to conventional visible imaging, chlorophyll fluorescence imaging is not sensitive to environmental light variations and provides single-channel images prone to a segmentation analysis by simple thresholding approaches. Among the various parameters used in chlorophyll fluorescence imaging, the maximum quantum yield of photosystem II photochemistry (Fv/Fm) is well adapted to phenotyping disease severity. Fv/Fm is an indicator of plant stress that displays a robust contrast between infected and healthy tissues. In the present paper, we aimed at the segmentation of Fv/Fm images to quantify disease severity. Based on the Fv/Fm values of each pixel of the image, a thresholding approach was developed to delimit diseased areas. A first step consisted in setting up thresholds to reproduce visual observations by trained raters of symptoms caused by Xanthomonas fuscans subsp. fuscans (Xff) CFBP4834-R on Phaseolus vulgaris cv. Flavert. In order to develop a thresholding approach valuable on any cultivars or species, a second step was based on modeling pixel-wise Fv/Fm-distributions as mixtures of Gaussian distributions. Such a modeling may discriminate various stages of the symptom development but over-weights artifacts that can occur on mock-inoculated samples. Therefore, we developed a thresholding approach based on the probability of misclassification of a healthy pixel. Then, a clustering step is performed on the diseased areas to discriminate between various stages of alteration of plant tissues. Notably, the use of chlorophyll fluorescence imaging could detect pre-symptomatic area. The interest of this image analysis procedure for assessing the levels of quantitative resistance

  13. Use of in vivo chlorophyll fluorescence to estimate photosynthetic activity and biomass productivity in microalgae grown in different culture systems

    Directory of Open Access Journals (Sweden)

    Félix L Figueroa

    2013-11-01

    Full Text Available In vivo chlorophyll fluorescence associated to Photosystem II is being used to evaluate photosynthetic activity of microalgae grown in different types of photobioreactors; however, controversy on methodology is usual. Several recommendations on the use of chlorophyll fluorescence to estimate electron transport rate and productivity of microalgae grown in thin-layer cascade cultivators and methacrylate cylindrical vessels are included. Different methodologies related to the measure of photosynthetic activity in microalgae are discussed: (1 measurement of light absorption, (2 determination of electron transport rates versus irradiance and (3 use of simplified devices based on pulse amplitude modulated (PAM fluorescence as Junior PAM or Pocket PAM with optical fiber and optical head as measuring units, respectively. Data comparisons of in vivo chlorophyll fluorescence by using these devices and other PAM fluorometers as Water-PAM in the microalga Chlorella sp. (Chlorophyta are presented. Estimations of carbon production and productivity by transforming electron transport rate to gross photosynthetic rate (as oxygen evolution using reported oxygen produced per photons absorbed values and carbon photosynthetic yield based on reported oxygen/carbon ratio are also shown. The limitation of ETR as estimator of photosynthetic and biomass productivity is discussed. Low cost:quality PAMs can promote monitoring of chlorophyll fluorescence in algal biotechnology to estimate the photosynthetic activity and biomass productivity.

  14. High resolution measurements of solar induced chlorophyll fluorescence in the Fraunhofer oxigen bands

    Science.gov (United States)

    Mazzoni, M.; Agati, G.; Cecchi, G.; Toci, G.; Mazzinghi, P.

    2017-11-01

    Spectra of solar radiance reflected by leaves close to the Fraunhofer bands show the net contribution of chlorophyll fluorescence emission which adds to the reflected solar spectra. In a laboratory experiment, a low stray light, high resolution, 0.85 m double monochromator was used to filter radiation living leaves still attached to the plant in correspondence of the 687 nm and 760 nm O2 absorption bands. Reference spectra from a non fluorescent white reference were also acquired. Acquisition was performed by a Microchannel plate (MCP) intensified diode array with 512 elements. A fit of the spectral data outside the absorption lines allowed to retrieve the spectral base-line as a function of wavelength for the reference panel and the leaf. Reflectance functions were determined extending the Plascyck equation system to all the resolved lines of the oxygen absorption bands and using the base-lines for the continuum values. Fluorescence was deduced from the same equation system, using both the measured leaf and reference radiance spectra and the leaf reflectance fitting function.

  15. Rapid effects of diverse toxic water pollutants on chlorophyll a fluorescence: variable responses among freshwater microalgae.

    Science.gov (United States)

    Choi, Chang Jae; Berges, John A; Young, Erica B

    2012-05-15

    Chlorophyll a fluorescence of microalgae is a compelling indicator of toxicity of dissolved water contaminants, because it is easily measured and responds rapidly. While different chl a fluorescence parameters have been examined, most studies have focused on single species and/or a narrow range of toxins. We assessed the utility of one chl a fluorescence parameter, the maximum quantum yield of PSII (F(v)/F(m)), for detecting effects of nine environmental pollutants from a range of toxin classes on 5 commonly found freshwater algal species, as well as the USEPA model species, Pseudokirchneriella subcapitata. F(v)/F(m) declined rapidly over glyphosate (glyphosate increased exponentially with concentration. F(v)/F(m) provides a sensitive and easily-measured parameter for rapid and cost-effective detection of effects of many dissolved toxins. Field-portable fluorometers will facilitate field testing, however distinct responses between different species may complicate net F(v)/F(m) signal from a community. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Evaluation of fluoranthene phytotoxicity in pea plants by Hill reaction and chlorophyll fluorescence.

    Science.gov (United States)

    Kummerová, Marie; Krulová, Jana; Zezulka, Stepán; Tríska, Jan

    2006-10-01

    The effect of both increased concentrations (0.01 and 1 mg l(-1)) of fluoranthene (FLT) and the duration of exposure (18 and 25 days) on the growth and photosynthetic processes in pea plants (Pisum sativum L., cv. Garde) was investigated. FLT concentration in roots and shoot of pea plants was also determined. The obtained results demonstrated that the higher concentration of FLT (1 mg l(-1)) significantly inhibited the growth of the pea plants after 25 days of the application, also affected the content of photosynthetic pigments (chlorophyll a, b and carotenoids), and the primary photochemical processes of photosynthesis. In chlorophyll fluorescence parameters, the significant increase of F(0) values and the decrease of F(V)/F(M) and Phi(II) values was recorded. The Hill reaction of isolated chloroplasts of pea plants was significantly inhibited after 25 days by presence of FLT (0.01 and 1 mg l(-1)) in nutrient solution, while after 18 days no significant response of Hill reaction activity was recorded. The fluoranthene content in roots and shoot of pea plants increased with increasing FLT concentration in the environment and the substantial accumulation of FLT was observed in the roots.

  17. Spatial heterogeneity in active chlorophyll fluorescence and PSII activity of coral tissues

    DEFF Research Database (Denmark)

    Ralph, P.J.; Gademann, R.; Larkum, A.W.D.

    2002-01-01

    Chlorophyll-a fluorescence was measured in six species of coral, using pulse-amplitude-modulated fluorometers employing fibre-optic probes with diameters of 8 mm, 1 mm and 140 µm. The 8-mm probe integrated responses over a large area, giving more weight to coenosarc than polyp tissue for Acropora...... to down-regulation at higher irradiances. Coenosarc and polyp tissue (both containing zooxanthellae) showed a wide range of responses in the other corals. Down-regulation of photosynthesis in a single polyp of Pocillopora damicornis was followed after exposure to moderate irradiance, with recovery...... occurring over a further 4 h of shade conditions. All the corals (Acropora millepora, A. nobilis, Cyphastrea serailia, Montipora tuberculosa, Pocillopora damicornis and Porites cylindrica) showed evidence of strong down-regulation of photosynthesis under high irradiance, and little evidence...

  18. Simple replacement of violaxanthin by zeaxanthin in LHC-II does not cause chlorophyll fluorescence quenching.

    Science.gov (United States)

    Dreuw, Andreas; Wormit, Michael

    2008-03-01

    Recently, a mechanism for the energy-dependent component (qE) of non-photochemical quenching (NPQ), the fundamental photo-protection mechanism in green plants, has been suggested. Replacement of violaxanthin by zeaxanthin in the binding pocket of the major light harvesting complex LHC-II may be sufficient to invoke efficient chlorophyll fluorescence quenching. Our quantum chemical calculations, however, show that the excited state energies of violaxanthin and zeaxanthin are practically identical when their geometry is constrained to the naturally observed structure of violaxanthin in LHC-II. Therefore, since violaxanthin does not quench LHC-II, zeaxanthin should not either. This theoretical finding is nicely in agreement with experimental results obtained by femtosecond spectroscopy on LHC-II complexes containing violaxanthin or zeaxanthin.

  19. Action spectra of oxygen production and chlorophyll a fluorescence in the green microalga Nannochloropsis oculata.

    Science.gov (United States)

    Tamburic, Bojan; Szabó, Milán; Tran, Nhan-An T; Larkum, Anthony W D; Suggett, David J; Ralph, Peter J

    2014-10-01

    The first complete action spectrum of oxygen evolution and chlorophyll a fluorescence was measured for the biofuel candidate alga Nannochloropsis oculata. A novel analytical procedure was used to generate a representative and reproducible action spectrum for microalgal cultures. The action spectrum was measured at 14 discrete wavelengths across the visible spectrum, at an equivalent photon flux density of 60 μmol photon sm(-2) s(-1). Blue light (∼ 414 nm) was absorbed more efficiently and directed to photosystem II more effectively than red light (∼ 679 nm) at light intensities below the photosaturation limit. Conversion of absorbed photons into photosynthetic oxygen evolution was maximised at 625 nm; however, this maximum is unstable since neighbouring wavelengths (646 nm) resulted in the lowest photosystem II operating efficiency. Identifying the wavelength-dependence of photosynthesis has clear implications to optimising growth efficiency and hence important economic implications to the algal biofuels and bioproducts industries. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Performance Indices in Wheat Chlorophyll a Fluorescence and Protein Quality Influenced by FHB

    Directory of Open Access Journals (Sweden)

    Valentina Spanic

    2017-11-01

    Full Text Available Very little is known about the physiological interactions between wheat quality and Fusarium head blight (FHB, which substantially reduces wheat grain yield and quality worldwide. In order to investigate stress-induced changes in flag leaves from plants artificially inoculated with Fusarium, we screened for chlorophyll a fluorescence transient at 1, 2, 4, 7 and 14 days after Fusarium inoculation. Our results indicate that the maximum quantum yield of photochemistry (Fv/Fm and the performance index (PI were not affected by FHB, but there were significant differences in those two traits between different varieties and measurement times. FHB caused a significant reduction in the percentage of glutenins (GLU, high-molecular-weight (HMW, and low-molecular-weight (LMW subunits in ‘Kraljica’ and ‘Golubica’, unlike ‘Vulkan’, where the percentage of GLU increased.

  1. Fluorescence-Based Approach to Estimate the Chlorophyll-A Concentration of a Phytoplankton Bloom in Ardley Cove (Antarctica

    Directory of Open Access Journals (Sweden)

    Chen Zeng

    2017-02-01

    Full Text Available A phytoplankton bloom occurred in Ardley Cove, King George Island in January 2016, during which maximum chlorophyll-a reached 9.87 mg/m3. Records show that blooms have previously not occurred in this area prior to 2010 and the average chlorophyll-a concentration between 1991 and 2009 was less than 2 mg/m3. Given the lack of in situ measurements and the poor performance of satellite algorithms in the Southern Ocean and Antarctic waters, we validate and assess several chlorophyll-a algorithms and apply an improved baseline fluorescence approach to examine this bloom event. In situ water properties including in vivo fluorescence, water leaving radiance, and solar irradiance were collected to evaluate satellite algorithms and characterize chlorophyll-a concentration, as well as dominant phytoplankton groups. The results validated the nFLH fluorescence baseline approach, resulting in a good agreement at this high latitude, high chlorophyll-a region with correlation at 59.46%. The dominant phytoplankton group within the bloom was micro-phytoplankton, occupying 79.58% of the total phytoplankton community. Increasing sea ice coverage and sea ice concentration are likely responsible for increasing phytoplankton blooms in the recent decade. Given the profound influence of climate change on sea-ice and phytoplankton dynamics in the region, it is imperative to develop accurate methods of estimating the spatial distribution and concentrations of the increasing occurrence of bloom events.

  2. Prospects for Chlorophyll Fluorescence Remote Sensing from the Orbiting Carbon Observatory-2

    Science.gov (United States)

    Frankenberg, Christian; Odell, Chris; Berry, Joseph; Guanter, Luis; Joiner, Joanna; Kohler, Philipp; Pollock, Randy; Taylor, Thomas E.

    2014-01-01

    The Orbiting Carbon Observatory-2 (OCO-2), scheduled to launch in July 2014, is a NASA mission designed to measure atmospheric CO2. Its main purpose is to allow inversions of net flux estimates of CO2 on regional to continental scales using the total column CO2 retrieved using high-resolution spectra in the 0.76, 1.6, and 2.0 nm ranges. Recently, it was shown that solar-induced chlorophyll fluorescence (SIF), a proxy for gross primary production (GPP, carbon uptake through photosynthesis), can be accurately retrieved from space using high spectral resolution radiances in the 750 nm range from the Japanese GOSAT and European GOME-2 instruments. Here, we use real OCO-2 thermal vacuum test data as well as a full repeat cycle (16 days) of simulated OCO-2 spectra under realistic conditions to evaluate the potential of OCO-2 for retrievals of chlorophyll fluorescence and also its dependence on clouds and aerosols. We find that the single-measurement precision is 0.3-0.5 Wm(exp -2)sr(exp -1) nm(exp -1) (15-25% of typical peak values), better than current measurements from space but still difficult to interpret on a single-sounding basis. The most significant advancement will come from smaller ground-pixel sizes and increased measurement frequency, with a 100-fold increase compared to GOSAT (and about 8 times higher than GOME-2). This will largely decrease the need for coarse spatial and temporal averaging in data analysis and pave the way to accurate local studies.We also find that the lack of full global mapping from the OCO-2 only incurs small representativeness errors on regional averages. Eventually, the combination of net ecosystem exchange (NEE) derived from CO2 source/sink inversions and SIF as proxy for GPP from the same satellite will provide a more process-based understanding of the global carbon cycle.

  3. Differential responses of seven contrasting species to high light using pigment and chlorophyll a fluorescence

    Directory of Open Access Journals (Sweden)

    Mittal S.

    2011-05-01

    Full Text Available High light intensity may induce severe photodamage to chloroplast and consequently cause decreases in the yield capacity of plants and destruction of pigments, causing an overall yellowing of the foliage. Thus, study related to light adaptation becomes necessary to understand adaptation processes in higher plants on the basis of which they are characterized as full sunlight or shade plants. Chlorophyll can be regarded as an intrinsic fluorescent probe of the photosynthetic system. The ecophysiological parameter related to plant performance and fitness i.e. in-situ chlorophyll fluorescence measurements were determined for different plant species in the medicinal plant garden of Banasthali University, Rajasthan. Miniaturized Pulse Amplitude Modulated Photosynthetic Yield Analyzers are primarily designed for measuring effective quantum yield (ΔF/Fm’ of photosystem II under momentary ambient light in the field. Photosynthetic yield measurements and light-response curves suggested a gradation of sun-adapted to shade-adapted behaviour of these plants in following order Withania somnifera> Catharanthus roseus> Datura stamonium> Vasica minora> Vasica adulta> Rauwolfia serpentina. As indicated by light response curves and pigment analysis, Datura stramonium, Withania somnifera and Catharanthus roseus competed well photosynthetically and are favoured while Rauwolfia serpentina, Vasica minora, Vasica adulta and Plumbago zeylanica were observed to be less competent photosynthetically. These light response curves and resultant cardinal points study gave insight into the ecophysiological characterization of the photosynthetic capacity of the plant and provides highly interesting parameters like electron transport rate, photo-inhibition, photosynthetically active photon flux density and yield on the basis of which light adaptability was screened for seven medicinally important plants.

  4. Impact of elevated temperatures on specific leaf weight, stomatal density, photosynthesis and chlorophyll fluorescence in soybean.

    Science.gov (United States)

    Jumrani, Kanchan; Bhatia, Virender Singh; Pandey, Govind Prakash

    2017-03-01

    High-temperature stress is a major environmental stress and there are limited studies elucidating its impact on soybean (Glycine max L. Merril.). The objectives of present study were to quantify the effect of high temperature on changes in leaf thickness, number of stomata on adaxial and abaxial leaf surfaces, gas exchange, chlorophyll fluorescence parameters and seed yield in soybean. Twelve soybean genotypes were grown at day/night temperatures of 30/22, 34/24, 38/26 and 42/28 °C with an average temperature of 26, 29, 32 and 35 °C, respectively, under greenhouse conditions. One set was also grown under ambient temperature conditions where crop season average maximum, minimum and mean temperatures were 28.0, 22.4 and 25.2 °C, respectively. Significant negative effect of temperature was observed on specific leaf weight (SLW) and leaf thickness. Rate of photosynthesis, stomatal conductance and water use efficiency declined as the growing temperatures increased; whereas, intercellular CO2 and transpiration rate were increased. With the increase in temperature chlorophyll fluorescence parameters such as Fv/Fm, qP and PhiPSII declined while there was increase in qN. Number of stomata on both abaxial and adaxial surface of leaf increased significantly with increase in temperatures. The rate of photosynthesis, PhiPSII, qP and SPAD values were positively associated with leaf thickness and SLW. This indicated that reduction in photosynthesis and associated parameters appears to be due to structural changes observed at higher temperatures. The average seed yield was maximum (13.2 g/pl) in plants grown under ambient temperature condition and declined by 8, 14, 51 and 65% as the temperature was increased to 30/22, 34/24, 38/26 and 42/28 °C, respectively.

  5. Monitoring terrestrial sun-induced chlorophyll fluorescence from GOSAT-FTS space measurements

    Science.gov (United States)

    Guanter, Luis; Voigt, Max; Kohler, Philipp; Zhang, Yongguang; Frankenberg, Christian; Lee, Jung-Eun; Jung, Martin

    2013-04-01

    A small fraction of the solar radiation absorbed by green leaves is emitted as chlorophyll-a fluorescence (SIF, for sun-induced chlorophyll fluorescence) after energy conversion. The SIF emission occurs as two broadband peaks centered in the red (685 nm) and far-red (740 nm) spectral regions. Extensive research at the laboratory and field scales during the last years has demonstrated that SIF is a good indicator of photosynthesis and gross primary production from the leaf to the canopy levels. Space observations of SIF can therefore provide a completely new view of vegetation photosynthesis on a global basis. Global maps of SIF have become recently available thanks to the advent of very high spectral resolution measurements by the Fourier Transform Spectrometer (FTS) on board the GOSAT platform. SIF is retrieved from measurements in the 750-770 nm window using solar Fraunhofer lines superposed to the SIF emission spectrum in that spectral range. The retrieval is based on the modeling of the in-filling of those Fraunhofer lines by fluorescence. More than 3 years of global SIF data are now available from GOSAT-FTS measurements. In this contribution we will present an overview of this new Earth observation data stream and its potential for an improved global monitoring of the carbon cycle and land-atmosphere interactions. In particular, we will summarize the results of on-going activities intended to (a) improve the retrieval of SIF from space, (b) understand the SIF signal at the biome scale represented by satellite observations as well as its relationship with EO-based greenness indices and meteorological parameters such as temperature, radiation and soil moisture, and (c) to determine for what biomes and environmental conditions fluorescence is a significantly better proxy for photosynthesis and gross primary production than traditional reflectance-based vegetation indices. For this purpose, a temporal series of about three years of global SIF retrievals has been

  6. [Effects of simulating acid rain on photosynthesis and chlorophyll fluorescence parameters of Quercus glauca Quercus glauca].

    Science.gov (United States)

    Wang, Sai; Yi, Li-Ta; Yu, Shu-Quan; Zhang, Chao; Shi, Jing-Jing

    2014-08-01

    At three levels of simulated acid rainfall intensities with pH values of 2.5 (severe), 40 (medium) and 5.6 (light) respectively, the responses of chlorophyll fluorescence and photosynthetic parameters of Quercus glauca seedlings were studied in three acid rainfall treatments, i. e. only the aboveground of seedlings exposed to acid rain (T1), both of the seedlings and soil exposed to acid rain (T2), only the soil exposed to acid rain (T3) compared with blank control (CK). Under the severe acid rainfall, T1 significantly inhibited chlorophyll synthesis, and thus reduced the primary photochemical efficiency of PS II ( F(v)/F(m)), potential activity of PS II (F(v)/F(o)) , apparent quantum (Y), net photosynthetic rate (P(n)), and transpiration rate (T(r)), but increased the light compensation point (LCP) and dark respiration rate (R(d)) of Q. glauca seedlings. T2 inhibited, but T3 played a little enhancement on the aforementioned parameters of Q. glauca seedlings. Under the conditions of medium and light acid rainfall intensities, the above parameters in the three treatments were higher than that of CK, except with lower R(d). The chlorophyll fluorescence and photosynthetic parameters showed a similar tendency in the three treatments, i. e. T2>T3 >T1. It indicated that T1 had the strongest inhibition on seedlings in condition of the severe acid rainfall, while T2 had the most dramatic facilitating effect on seedlings under the medium and light acid rainfall. Intensity of acid rainfall had significant influences on SPAD, F(v)/F(m), F(v)/F(o), Y, P(n), T(r), and maximum photosynthetic rate (A(max)), whereas treatments of acid rainfall affected SPAD, F(v)/F(m), Y, P(n), T(r), A(max) and light saturation point (LSP). The interaction of acid rainfall intensities and treatments played significant effects on SPAD, F(v)/F(m), Y, P(n) and A(max).

  7. Rapid assessment of different oxygenic phototrophs and single-cell photosynthesis with multicolour variable chlorophyll fluorescence imaging

    DEFF Research Database (Denmark)

    Trampe, Erik Christian Løvbjerg; Kolbowski, J.; Schreiber, U.

    2011-01-01

    , red or white light. Automated sequential exposure of microscopic samples to the three excitation colours enables subsequent deconvolution of the resulting fluorescence signals and colour marking of cells with different photopigmentation, i.e., cyanobacteria, green algae, red algae and diatoms......We present a new system for microscopic multicolour variable chlorophyll fluorescence imaging of aquatic phototrophs. The system is compact and portable and enables microscopic imaging of photosynthetic performance of individual cells and chloroplasts using different combinations of blue, green...

  8. Chlorophyll a fluorescence induction (Kautsky curve) in a Venus flytrap (Dionaea muscipula) leaf after mechanical trigger hair irritation.

    NARCIS (Netherlands)

    Vredenberg, W.J.; Pavlovic, A.

    2013-01-01

    This paper describes experiments on transient changes in chlorophyll a fluorescence in traps of the carnivorous plant Venus flytrap (Dionaea muscipula) that occur in association with mechanical stimulation of trigger hairs and propagation of action potentials (APs). The experiments show the

  9. The Impact of Different Water Regime on Chlorophyll Fluorescence of Pyrus pyraster L. and Sorbus domestica L

    Directory of Open Access Journals (Sweden)

    Viera Šajbidorová

    2015-01-01

    Full Text Available The water deficit is considered to be significant cause of photosynthesis defects. Measuring of chlorophyll fluorescence is one of the methods revealing defects in the photosynthetic apparatus. The experiment was established with two woody plant (Pyrus pyraster L. and Sorbus domestica L. cultivated in two different regimes of the substrate saturation. The measurement of the modulated fluorescence of chlorophyll a was done by FMS1 fluorometer during three-week period between June and September (2012 and 2013. There were analysed selected parameters of chlorophyll fluorescence: Fv/Fm – maximum quantum efficiency of PSII, ΦPSII – effective quantum yield of PSII and RFD – chlorophyll fluorescence decrease ratio. According to the obtained results, Pyrus pyraster has probably higher potential for adaptation to water deficiency. There were recorded the significant decreases mainly in the values of parameter RFD and ΦPSII for Sorbus domestica within duration of experiment with different water regime in both growing seasons 2012 and 2013. The results document a weak sensitivity of the parameter Fv/Fm on changes in the amount of available water in the substrate in both taxa.

  10. Chlorophyll fluorescence as a parameter for frost hardiness in winter wheat. A comparison with other hardiness parameters.

    NARCIS (Netherlands)

    Clement, JMAM; vanHasselt, PR

    1996-01-01

    Frost hardiness of winter wheat leaves (Triticum aestivum L. cv. Urban) was measured during an eight weeks hardening period using chlorophyll fluorescence. Determination of frost induced damage after freezing, measured as the decrease of photochemical capacity of photosystem II (F-V/F-M =

  11. Comparison of Sun-Induced Chlorophyll Fluorescence Estimates Obtained from Four Portable Field Spectroradiometers

    Science.gov (United States)

    Julitta, Tommaso; Corp, Lawrence A.; Rossini, Micol; Burkart, Andreas; Cogliati, Sergio; Davies, Neville; Hom, Milton; Mac Arthur, Alasdair; Middleton, Elizabeth M.; Rascher, Uwe; hide

    2016-01-01

    Remote Sensing of Sun-Induced Chlorophyll Fluorescence (SIF) is a research field of growing interest because it offers the potential to quantify actual photosynthesis and to monitor plant status. New satellite missions from the European Space Agency, such as the Earth Explorer 8 FLuorescence EXplorer (FLEX) mission-scheduled to launch in 2022 and aiming at SIF mapping-and from the National Aeronautics and Space Administration (NASA) such as the Orbiting Carbon Observatory-2 (OCO-2) sampling mission launched in July 2014, provide the capability to estimate SIF from space. The detection of the SIF signal from airborne and satellite platform is difficult and reliable ground level data are needed for calibration/validation. Several commercially available spectroradiometers are currently used to retrieve SIF in the field. This study presents a comparison exercise for evaluating the capability of four spectroradiometers to retrieve SIF. The results show that an accurate far-red SIF estimation can be achieved using spectroradiometers with an ultrafine resolution (less than 1 nm), while the red SIF estimation requires even higher spectral resolution (less than 0.5 nm). Moreover, it is shown that the Signal to Noise Ratio (SNR) plays a significant role in the precision of the far-red SIF measurements.

  12. Multispectral In-situ Measurements of Organic Matter and Chlorophyll Fluorescence in Seawater: Documenting the Intrusion of the Mississippi River Plume in the West Florida Shelf

    Science.gov (United States)

    DelCastillo, Carlos E.; Coble, Paula G.; Conmy, Robyn N.; Mueller-Karger, Frank E.; Vanderbloomen, Lisa; Vargo, Gabriel A.

    2000-01-01

    We performed multispectral in-situ fluorescence measurement of colored dissolved organic matter and chlorophyll in surface water of the West Florida Shelf using West Labs Spectral absorption and Fluorescence Instrument (SAFIre). Continuous measurements underway allowed us to simultaneously map the dispersion of riverine organic material and chlorophyll on the shelf. By using two fluorescence emission ratios we were able to differentiate between riverine and marine CDOM. Our data also showed unusually high concentrations of CDOM offshore. These were attributed to an intrusion of the Mississippi River Plume. We performed limited comparisons between in-situ chlorophyll concentrations measured with SAFIre and chlorophyll values obtained from SeaWiFS satellite data using OC4 and MODIS algorithm. Our results show that, although both algorithms overestimated chlorophyll, MODIS performed better than OC4, particularly in areas with high CDOM concentrations. Analysis of the relationship between chlorophyll and CDOM concentrations within the study area showed regional variability causes by differences in river source.

  13. Light stress effect and by nitrogen deficiency in plants of Petiveria alliacea measured with two-chlorophyll-fluorescence technique

    Science.gov (United States)

    Zuluaga, H.; Oviedo, A.; Solarte, Efrain; Pena, E. J.

    2004-10-01

    The chlorophyll fluorescence was studied in Petiveria alliacea plants exposed to different nitrogen concentrations and light radiation, the response was measured by two different forms; (1) measuring the photosynthetic efficiency with a pulse amplitude modulated fluorometro (PAM) emitted by a 650 nm diode and (2) measuring the fluorescence spectra caused by high power 452 nm diode with a SD2000 spectrometer. It was found out that the photosynthetic efficiency decreased in the plants exposed to high radiance and low nitrogen. Two chlorophyll fluorescence peaks were observed on 684 nm and 739 nm, the intensities in this wavelengths are inversely related with the light radiance. The correlation between the FIR and photosynthetic efficiency was very strong (r2 = -0.809, p Alliacea plants.

  14. Growth and chlorophyll fluorescence under salinity stress in sugar beet (Beta vulgaris L.

    Directory of Open Access Journals (Sweden)

    Fadi Abbas

    2014-02-01

    Full Text Available This study was carried out in the General Commission for Scientific Agricultural Research (GCSAR, Syria, at Der EzZour Agricultural Research Center, from 2008-2010, to examine the effect of salt conditions on some growth attributes and chlorophyll fluorescence in 10 Sugar Beet (Beta vulgaris L. genotypes under salinity stress. Sugar beet plants were irrigated with saline water, having electrical conductivity ranged from 8.6-10 dS.m-1during first year and 8.4-10.4 dS.m-1 during second year. A randomized completely block design with three replicates was used. The results showed that all studied growth attributes, leaf area, leaf number, relative growth rate, and net assimilation rate were decreased in salinity stress conditions compared to the controlled state. The findings indicated that salinity caused a decrement of light utilizing through increased values of fluorescence origin (fo, decreased values of fluorescence maximum (fm, and maximum yield of quantum in photosystem-II (fv/fm. Genotypes differed significantly in all studied attributes except in leaf number. Under salt conditions, Brigitta (monogerm achieved an increase in net assimilation rate, while Kawimera (multigerm achieved the lowest decrement in quantum yield in photosystem-II. Further studies are necessary to correlate the yield with yield components under similar conditions to determine the most tolerant genotype.International Journal of Environment Vol.3(1 2014: 1-9 DOI: http://dx.doi.org/10.3126/ije.v3i1.9937

  15. Deriving chlorophyll fluorescence emissions of vegetation canopies from high resolution field reflectance spectra

    Science.gov (United States)

    Middleton, Elizabeth M.; Corp, Lawrence A.; Daughtry, Craig S.; Entcheva Campbell, Petya K.; Butcher, L. Maryn

    2005-11-01

    Fluorescence of foliage in the laboratory has proven more rigorous than reflectance for correlation to plant physiology. Especially useful are emissions produced from two stable red and far-red chlorophyll fluorescence (ChlF) peaks centered at 685 nm and 735 nm. Methods have been developed elsewhere to extract steady state solar induced fluorescence (SIF) from apparent reflectance of vegetation canopies/landscapes using the Fraunhofer Line Depth (FLD) principal. Our study utilized these methods in conjunction with field-acquired high spectral resolution canopy reflectance spectra obtained in 2004 and 2005 over corn crops and small tree plots of three deciduous species (red maple, tulip poplar, sweet gum). Leaf level measurements were also made of foliage which included ChlF, photosynthesis, and leaf constituents (photosynthetic pigment, carbon (C), and nitrogen (N) contents). As part of ongoing experiments, measurements were made on N application plots within corn (280, 140, 70, and 0 kg N/ha) and tree (0, 37.5, 75, 112.5, 150 kg N /ha) sites at the USDA/Agriculture Research Service in Beltsville, MD. SIF intensities for ChlF were derived directly from canopy reflectance spectra in specific narrow- band regions associated with atmospheric oxygen absorption features centered at 688 and 760 nm. The red/far-red SIF ratio (SIFratio) derived from these field reflectance spectra successfully discriminated foliar pigment ratios altered by N application rates in both corn crops. This ratio was also positively correlated to the C/N ratio at leaf and canopy levels, for the available corn data (e.g., 2004). No consistent N treatment or species differences in SIF were detected in the tree foliage, but additional 2005 data are forthcoming. This study has relevance to future passive satellite remote sensing approaches to monitoring C dynamics from space.

  16. PhotoSpec - Ground-based Remote Sensing of Solar-Induced Chlorophyll Fluorescence

    Science.gov (United States)

    Grossmann, K.; Frankenberg, C.; Seibt, U.; Hurlock, S. C.; Pivovaroff, A.; Stutz, J.

    2015-12-01

    Solar-Induced Chlorophyll Fluorescence (SIF) emitted from vegetation can be used as a constraint for photosynthetic activity and is now observable on a global scale from space. However, many issues on a leaf-to-canopy scale remain poorly understood, such as influences on the SIF signal of environmental conditions, water stress, or radiation. Here, we report on the development and characterization of a novel ground-based spectrometer system for measuring SIF from natural ecosystems (http://www.kiss.caltech.edu/study/photosynthesis/technology.html). The instrumental set-up, requirements, and measurement technique are based on decades of experience using Differential Optical Absorption Spectroscopy (DOAS), an established method to measure atmospheric trace gases. The instrument consists of three thermally stabilized commercial spectrometers that are linked to a 2D scanning telescope unit via optical fiber bundles. The spectrometers cover an SIF retrieval wavelength range at high spectral resolution (670 - 780 nm, 0.1 nm FWHM), but also provide moderate resolution spectra (400 - 800 nm, 1.5 nm FWHM) in order to retrieve vegetation indices and the photochemical reflectance index (PRI). In addition to the instrumental set-up, we will show initial results of test and field measurements with the new instrument that examine the diurnal cycle of the SIF signal of different California native and non-native plants and its correlation with CO2 fluxes. Observations were made under different environmental conditions, variable water and nutrient stress, and with different viewing geometries. We also used concurrent observations by a photosynthetically active radiation (PAR) sensor and a portable chlorophyll fluorometer (PAM) to link the SIF signal to plant metabolism and carbon cycling under a range of environmental conditions.

  17. Relationship between leaf optical properties, chlorophyll fluorescence and pigment changes in senescing Acer saccharum leaves.

    Science.gov (United States)

    Junker, Laura Verena; Ensminger, Ingo

    2016-06-01

    The ability of plants to sequester carbon is highly variable over the course of the year and reflects seasonal variation in photosynthetic efficiency. This seasonal variation is most prominent during autumn, when leaves of deciduous tree species such as sugar maple (Acer saccharum Marsh.) undergo senescence, which is associated with downregulation of photosynthesis and a change of leaf color. The remote sensing of leaf color by spectral reflectance measurements and digital repeat images is increasingly used to improve models of growing season length and seasonal variation in carbon sequestration. Vegetation indices derived from spectral reflectance measurements and digital repeat images might not adequately reflect photosynthetic efficiency of red-senescing tree species during autumn due to the changes in foliar pigment content associated with autumn phenology. In this study, we aimed to assess how effectively several widely used vegetation indices capture autumn phenology and reflect the changes in physiology and photosynthetic pigments during autumn. Chlorophyll fluorescence and pigment content of green, yellow, orange and red leaves were measured to represent leaf senescence during autumn and used as a reference to validate and compare vegetation indices derived from leaf-level spectral reflectance measurements and color analysis of digital images. Vegetation indices varied in their suitability to track the decrease of photosynthetic efficiency and chlorophyll content despite increasing anthocyanin content. Commonly used spectral reflectance indices such as the normalized difference vegetation index and photochemical reflectance index showed major constraints arising from a limited representation of gradual decreases in chlorophyll content and an influence of high foliar anthocyanin levels. The excess green index and green-red vegetation index were more suitable to assess the process of senescence. Similarly, digital image analysis revealed that vegetation

  18. Steady-state chlorophyll fluorescence (Fs) as a tool to monitor plant heat and drought stress

    Science.gov (United States)

    Cendrero Mateo, M.; Carmo-Silva, A.; Salvucci, M.; Moran, S. M.; Hernandez, M.

    2012-12-01

    Crop yield decreases when photosynthesis is limited by heat or drought conditions. Yet farmers do not monitor crop photosynthesis because it is difficult to measure at the field scale in real time. Steady-state chlorophyll fluorescence (Fs) can be used at the field level as an indirect measure of photosynthetic activity in both healthy and physiologically-perturbed vegetation. In addition, Fs can be measured by satellite-based sensors on a regular basis over large agricultural regions. In this study, plants of Camelina sativa grown under controlled conditions were subjected to heat and drought stress. Gas exchange and Fs were measured simultaneously with a portable photosynthesis system under light limiting and saturating conditions. Results showed that Fs was directly correlated with net CO2 assimilation (A) and inversely correlated with non-photochemical quenching (NPQ). Analysis of the relationship between Fs and Photosynthetically Active Radiation (PAR) revealed significant differences between control and stressed plants that could be used to track the status, resilience, and recovery of photochemical processes. In summary, the results provide evidence that Fs measurements, even without normalization, are an easy means to monitor changes in plant photosynthesis, and therefore, provide a rapid assessment of plant stress to guide farmers in resource applications. Figure1. Net CO2 assimilation rate (A) of Camelina sativa plants under control conditions and after heat stress exposure for 1 or 3 days (1d-HS and 3d-HS, respectively) (right) and control, drought and re-watering conditions (left). Conditions for infra-red gas analysis were: reference CO2 = 380 μmol mol-1, PPFD = 500 μmol m-2 s-1 and Tleaf set to 25°C (control, drought and re-water) or 35°C (HS). Different letters denote significant differences at the α=0.05 level. Values are means±SEM (n=10). Figure 2. Stable chlorophyll fluorescence (Fs) of Camelina sativa plants under control conditions and

  19. Estimating chlorophyll content and photochemical yield of photosystem II (ΦPSII) using solar-induced chlorophyll fluorescence measurements at different growing stages of attached leaves.

    Science.gov (United States)

    Tubuxin, Bayaer; Rahimzadeh-Bajgiran, Parinaz; Ginnan, Yusaku; Hosoi, Fumiki; Omasa, Kenji

    2015-09-01

    This paper illustrates the possibility of measuring chlorophyll (Chl) content and Chl fluorescence parameters by the solar-induced Chl fluorescence (SIF) method using the Fraunhofer line depth (FLD) principle, and compares the results with the standard measurement methods. A high-spectral resolution HR2000+ and an ordinary USB4000 spectrometer were used to measure leaf reflectance under solar and artificial light, respectively, to estimate Chl fluorescence. Using leaves of Capsicum annuum cv. 'Sven' (paprika), the relationships between the Chl content and the steady-state Chl fluorescence near oxygen absorption bands of O2B (686nm) and O2A (760nm), measured under artificial and solar light at different growing stages of leaves, were evaluated. The Chl fluorescence yields of ΦF 686nm/ΦF 760nm ratios obtained from both methods correlated well with the Chl content (steady-state solar light: R(2) = 0.73; artificial light: R(2) = 0.94). The SIF method was less accurate for Chl content estimation when Chl content was high. The steady-state solar-induced Chl fluorescence yield ratio correlated very well with the artificial-light-induced one (R(2) = 0.84). A new methodology is then presented to estimate photochemical yield of photosystem II (ΦPSII) from the SIF measurements, which was verified against the standard Chl fluorescence measurement method (pulse-amplitude modulated method). The high coefficient of determination (R(2) = 0.74) between the ΦPSII of the two methods shows that photosynthesis process parameters can be successfully estimated using the presented methodology. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  20. On the analysis of non-photochemical chlorophyll fluorescence quenching curves: I. Theoretical considerations.

    Science.gov (United States)

    Holzwarth, Alfred R; Lenk, Dagmar; Jahns, Peter

    2013-06-01

    Non-photochemical quenching (NPQ) protects photosynthetic organisms against photodamage by high light. One of the key measuring parameters for characterizing NPQ is the high-light induced decrease in chlorophyll fluorescence. The originally measured data are maximal fluorescence (Fm') signals as a function of actinic illumination time (Fm'(t)). Usually these original data are converted into the so-called Stern-Volmer quenching function, NPQSV(t), which is then analyzed and interpreted in terms of various NPQ mechanisms and kinetics. However, the interpretation of this analysis essentially depends on the assumption that NPQ follows indeed a Stern-Volmer relationship. Here, we question this commonly assumed relationship, which surprisingly has never been proven. We demonstrate by simulation of quenching data that particularly the conversion of time-dependent quenching curves like Fm'(t) into NPQSV(t) is (mathematically) not "innocent" in terms of its effects. It distorts the kinetic quenching information contained in the originally measured function Fm'(t), leading to a severe (often sigmoidal) distortion of the time-dependence of quenching and has negative impact on the ability to uncover the underlying quenching mechanisms and their contribution to the quenching kinetics. We conclude that the commonly applied analysis of time-dependent NPQ in NPQSV(t) space should be reconsidered. First, there exists no sound theoretical basis for this common practice. Second, there occurs no loss of information whatsoever when analyzing and interpreting the originally measured Fm'(t) data directly. Consequently, the analysis of Fm'(t) data has a much higher potential to provide correct mechanistic answers when trying to correlate quenching data with other biochemical information related to quenching. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Simulations of chlorophyll fluorescence incorporated into the Community Land Model version 4.

    Science.gov (United States)

    Lee, Jung-Eun; Berry, Joseph A; van der Tol, Christiaan; Yang, Xi; Guanter, Luis; Damm, Alexander; Baker, Ian; Frankenberg, Christian

    2015-09-01

    Several studies have shown that satellite retrievals of solar-induced chlorophyll fluorescence (SIF) provide useful information on terrestrial photosynthesis or gross primary production (GPP). Here, we have incorporated equations coupling SIF to photosynthesis in a land surface model, the National Center for Atmospheric Research Community Land Model version 4 (NCAR CLM4), and have demonstrated its use as a diagnostic tool for evaluating the calculation of photosynthesis, a key process in a land surface model that strongly influences the carbon, water, and energy cycles. By comparing forward simulations of SIF, essentially as a byproduct of photosynthesis, in CLM4 with observations of actual SIF, it is possible to check whether the model is accurately representing photosynthesis and the processes coupled to it. We provide some background on how SIF is coupled to photosynthesis, describe how SIF was incorporated into CLM4, and demonstrate that our simulated relationship between SIF and GPP values are reasonable when compared with satellite (Greenhouse gases Observing SATellite; GOSAT) and in situ flux-tower measurements. CLM4 overestimates SIF in tropical forests, and we show that this error can be corrected by adjusting the maximum carboxylation rate (Vmax ) specified for tropical forests in CLM4. Our study confirms that SIF has the potential to improve photosynthesis simulation and thereby can play a critical role in improving land surface and carbon cycle models. © 2015 John Wiley & Sons Ltd.

  2. Validation of the chlorophyll fluorescence imaging method (CFI for early detection of herbicide resistance in weeds

    Directory of Open Access Journals (Sweden)

    Menegat, Alexander

    2014-02-01

    Full Text Available The increasing number of herbicide tolerant weed populations is illustrating the increasing demand for reliable methods for an accelerated detection of herbicide tolerance compared to greenhouse studies. Several methods for resistance quick detection have been published in previous years. One of the recent methods is the Chlorophyll Fluorescence Imaging Method (CFI. For this method changes in photosynthetic activity of the target organisms, caused by herbicides, are determined. General assumption of this method in terms of herbicide resistance detection is that each herbicidal compound, independent of the mode of action, will cause changes within the photosynthetic apparatus of the target organisms. This effect already could be confirmed for several modes of action (PSII, ALS, ACCase, EPSPS, synth. Auxins. Aim of this study is to validate this novel method on the basis of greenhouse experiments and single nucleotide polymorphisms (SNP analysis. The resistance profiles of 10 black-grass populations (Alopecurus myosuroides Huds. have been determined in greenhouse herbicide efficacy trials and constitutive SNP analyses of the survivors. With the CFI-method it was possible to detect the resistance profile as well as the resistance frequency within the populations. The results from the greenhouse experiments could be reproduced with conformity of 94%. This result is valid for the tested herbicides mesosulfuron, pyroxsulam as well as clodinafop and pinoxaden.

  3. Effects of selenite on chlorophyll fluorescence, starch content and fatty acid in the duckweed Landoltia punctata.

    Science.gov (United States)

    Zhong, Yu; Li, Yang; Cheng, Jay J

    2016-09-01

    Developing a Se-enriched feed for animal has become a considerable effort. In this study, Landoltia punctata 7449 was grown over a 12 day period under concentrations of selenite (Na2SeO3) from 0 to 80 μmol L(-1). The growth rate, the chlorophyll fluorescence, the starch content and fatty acid were measured. Se at low concentrations of ≤20 μmol L(-1) had positive effects also on growth rate, fatty acid content and yield of the L. punctata. The appropriate Se treatment enhanced the activity of the photosynthetic system by increasing Fv, Fm, Fv/Fm and Fv/Fo and decreasing Fo. However, negative impact to the L. punctata was observed when the duckweed was exposed to high Se concentrations (≥40 μmol L(-1)). Significant increases in starch content in the duckweed were observed after Se application. The present study suggests that the changes in growth rate, the photosynthetic system, the starch content and the fatty acid were closely associated with the application of Se. An increased Se concentration (0-20 μmol L(-1)) in duckweed could positively induce photosynthesis, thereby increasing the yield of L. punctata and could be a resource for high nutritive quality Se-enrich feed.

  4. Short-duration exposure to radiofrequency electromagnetic radiation alters the chlorophyll fluorescence of duckweeds (Lemna minor).

    Science.gov (United States)

    Senavirathna, Mudalige Don Hiranya Jayasanka; Takashi, Asaeda; Kimura, Yuichi

    2014-12-01

    Plants growing in natural environments are exposed to radiofrequency electromagnetic radiation (EMR) emitted by various communication network base stations. The environmental concentration of this radiation is increasing rapidly with the congested deployment of base stations. Although numerous scientific studies have been conducted to investigate the effects of EMR on the physiology of humans and animals, there have been few attempts to investigate the effects of EMR on plants. In this study, we attempted to evaluate the effects of EMR on photosynthesis by investigating the chlorophyll fluorescence (ChF) parameters of duckweed fronds. During the experiment, the fronds were tested with 2, 2.5, 3.5, 5.5 and 8 GHz EMR frequencies, which are not widely studied even though there is a potentially large concentration of these frequencies in the environment. The duckweed fronds were exposed to EMR for 30 min, 1 h and 24 h durations with electric field strength of 45-50 V/m for each frequency. The results indicated that exposure to EMR causes a change in the non-photochemical quenching of the duckweeds. The changes varied with the frequency of the EMR and were time-varying within a particular frequency. The temperature remained unchanged in the duckweed fronds upon exposure to EMR, which confirms that the effect is non-thermal.

  5. Chlorophyll Fluorescence Data Reveals Climate-Related Photosynthesis Seasonality in Amazonian Forests

    Directory of Open Access Journals (Sweden)

    Gabriel Bertani

    2017-12-01

    Full Text Available Amazonia is the world largest tropical forest, playing a key role in the global carbon cycle. Thus, understanding climate controls of photosynthetic activity in this region is critical. The establishment of the relationship between photosynthetic activity and climate has been controversial when based on conventional remote sensing-derived indices. Here, we use nine years of solar-induced chlorophyll fluorescence (ChlF data from the Global Ozone Monitoring Experiment (GOME-2 sensor, as a direct proxy for photosynthesis, to assess the seasonal response of photosynthetic activity to solar radiation and precipitation in Amazonia. Our results suggest that 76% of photosynthesis seasonality in Amazonia is explained by seasonal variations of solar radiation. However, 13% of these forests are limited by precipitation. The combination of both radiation and precipitation drives photosynthesis in the remaining 11% of the area. Photosynthesis tends to rise only after radiation increases in 61% of the forests. Furthermore, photosynthesis peaks in the wet season in about 58% of the Amazon forest. We found that a threshold of ≈1943 mm per year can be defined as a limit for precipitation phenological dependence. With the potential increase in the frequency and intensity of extreme droughts, forests that have the photosynthetic process currently associated with radiation seasonality may shift towards a more water-limited system.

  6. DART: Recent Advances in Remote Sensing Data Modeling With Atmosphere, Polarization, and Chlorophyll Fluorescence

    Science.gov (United States)

    Gastellu-Etchegorry, Jean-Phil; Lauret, Nicolas; Yin, Tiangang; Landier, Lucas; Kallel, Abdelaziz; Malenovsky, Zbynek; Bitar, Ahmad Al; Aval, Josselin; Benhmida, Sahar; Qi, Jianbo; hide

    2017-01-01

    To better understand the life-essential cycles and processes of our planet and to further develop remote sensing (RS) technology, there is an increasing need for models that simulate the radiative budget (RB) and RS acquisitions of urban and natural landscapes using physical approaches and considering the three-dimensional (3-D) architecture of Earth surfaces. Discrete anisotropic radiative transfer (DART) is one of the most comprehensive physically based 3-D models of Earth-atmosphere radiative transfer, covering the spectral domain from ultraviolet to thermal infrared wavelengths. It simulates the optical 3-DRB and optical signals of proximal, aerial, and satellite imaging spectrometers and laser scanners, for any urban and/or natural landscapes and for any experimental and instrumental configurations. It is freely available for research and teaching activities. In this paper, we briefly introduce DART theory and present recent advances in simulated sensors (LiDAR and cameras with finite field of view) and modeling mechanisms (atmosphere, specular reflectance with polarization and chlorophyll fluorescence). A case study demonstrating a novel application of DART to investigate urban landscapes is also presented.

  7. Global and Time-Resolved Monitoring of Crop Photosynthesis with Chlorophyll Fluorescence

    Science.gov (United States)

    Guanter, Luis; Zhang, Yongguang; Jung, Martin; Joiner, Joanna; Voigt, Maximilian; Berry, Joseph A.; Frankenberg, Christian; Huete, Alfredo R.; Zarco-Tejada, Pablo; Lee, Jung-Eun; hide

    2014-01-01

    Photosynthesis is the process by which plants harvest sunlight to produce sugars from carbon dioxide and water. It is the primary source of energy for all life on Earth; hence it is important to understand how this process responds to climate change and human impact. However, model-based estimates of gross primary production (GPP, output from photosynthesis) are highly uncertain, in particular over heavily managed agricultural areas. Recent advances in spectroscopy enable the space-based monitoring of sun-induced chlorophyll fluorescence (SIF) from terrestrial plants. Here we demonstrate that spaceborne SIF retrievals provide a direct measure of the GPP of cropland and grassland ecosystems. Such a strong link with crop photosynthesis is not evident for traditional remotely sensed vegetation indices, nor for more complex carbon cycle models. We use SIF observations to provide a global perspective on agricultural productivity. Our SIF-based crop GPP estimates are 50-75% higher than results from state-of-the-art carbon cycle models over, for example, the US Corn Belt and the Indo-Gangetic Plain, implying that current models severely underestimate the role of management. Our results indicate that SIF data can help us improve our global models for more accurate projections of agricultural productivity and climate impact on crop yields. Extension of our approach to other ecosystems, along with increased observational capabilities for SIF in the near future, holds the prospect of reducing uncertainties in the modeling of the current and future carbon cycle.

  8. In Vivo Assessment of Cold Tolerance through Chlorophyll-a Fluorescence in Transgenic Zoysiagrass Expressing Mutant Phytochrome A

    Science.gov (United States)

    Gururani, Mayank Anand; Venkatesh, Jelli; Ganesan, Markkandan; Strasser, Reto Jörg; Han, Yunjeong; Kim, Jeong-Il; Lee, Hyo-Yeon; Song, Pill-Soon

    2015-01-01

    Chlorophyll-a fluorescence analysis provides relevant information about the physiology of plants growing under abiotic stress. In this study, we evaluated the influence of cold stress on the photosynthetic machinery of transgenic turfgrass, Zoysia japonica, expressing oat phytochrome A (PhyA) or a hyperactive mutant phytochrome A (S599A) with post-translational phosphorylation blocked. Biochemical analysis of zoysiagrass subjected to cold stress revealed reduced levels of hydrogen peroxide, increased proline accumulation, and enhanced specific activities of antioxidant enzymes compared to those of control plants. Detailed analyses of the chlorophyll-a fluorescence data through the so-called OJIP test exhibited a marked difference in the physiological status among transgenic and control plants. Overall, these findings suggest an enhanced level of cold tolerance in S599A zoysiagrass cultivars as reflected in the biochemical and physiological analyses. Further, we propose that chlorophyll-a fluorescence analysis using OJIP test is an efficient tool in determining the physiological status of plants under cold stress conditions. PMID:26010864

  9. In Vivo Assessment of Cold Tolerance through Chlorophyll-a Fluorescence in Transgenic Zoysiagrass Expressing Mutant Phytochrome A.

    Directory of Open Access Journals (Sweden)

    Mayank Anand Gururani

    Full Text Available Chlorophyll-a fluorescence analysis provides relevant information about the physiology of plants growing under abiotic stress. In this study, we evaluated the influence of cold stress on the photosynthetic machinery of transgenic turfgrass, Zoysia japonica, expressing oat phytochrome A (PhyA or a hyperactive mutant phytochrome A (S599A with post-translational phosphorylation blocked. Biochemical analysis of zoysiagrass subjected to cold stress revealed reduced levels of hydrogen peroxide, increased proline accumulation, and enhanced specific activities of antioxidant enzymes compared to those of control plants. Detailed analyses of the chlorophyll-a fluorescence data through the so-called OJIP test exhibited a marked difference in the physiological status among transgenic and control plants. Overall, these findings suggest an enhanced level of cold tolerance in S599A zoysiagrass cultivars as reflected in the biochemical and physiological analyses. Further, we propose that chlorophyll-a fluorescence analysis using OJIP test is an efficient tool in determining the physiological status of plants under cold stress conditions.

  10. Chlorophyll fluorescence in the leaves of Tradescantia species of different ecological groups: induction events at different intensities of actinic light.

    Science.gov (United States)

    Ptushenko, Vasily V; Ptushenko, Elena A; Samoilova, Olga P; Tikhonov, Alexander N

    2013-11-01

    Chlorophyll fluorescence analysis is one of the most convenient and widespread techniques used to monitor photosynthesis performance in plants. In this work, after a brief overview of the mechanisms of regulation of photosynthetic electron transport and protection of photosynthetic apparatus against photodamage, we describe results of our study of the effects of actinic light intensity on photosynthetic performance in Tradescantia species of different ecological groups. Using the chlorophyll fluorescence as a probe of photosynthetic activity, we have found that the shade-tolerant species Tradescantia fluminensis shows a higher sensitivity to short-term illumination (≤20min) with low and moderate light (≤200μEm(-2)s(-1)) as compared with the light-resistant species Tradescantia sillamontana. In T. fluminensis, non-photochemical quenching of chlorophyll fluorescence (NPQ) and photosystem II operational efficiency (parameter ΦPSII) saturate as soon as actinic light reaches ≈200μEm(-2)s(-1). Otherwise, T. sillamontana revealed a higher capacity for NPQ at strong light (≥800μEm(-2)s(-1)). The post-illumination adaptation of shade-tolerant plants occurs slower than in the light-resistant species. The data obtained are discussed in terms of reactivity of photosynthetic apparatus to short-term variations of the environment light. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. Quality assessment of urban trees using growth visual and chlorophyll fluorescence indicators

    Directory of Open Access Journals (Sweden)

    Uhrin Peter

    2016-06-01

    Full Text Available Urbanised landscape represents composed structures of technical and biotic elements where social and economy activities create living space for human society but with strongly changed environment. To dominant characters belong climate changes with increased air temperature, drought and emission load, which has developed wide spectrum of stress factors influencing the urban vegetation. For the assessment of plant growth and adaptation response, we have used Sycamore maple (Acer pseudoplatanus L. as study model woody plant. In the framework of visual characters, we assessed the following indicators: (a assimilation organs (leaf necrosis; (b crown quality (degree of foliage and degree of dead tree crown; (c trunk and branch quality (mechanical damage, incidence of wood destroying fungus and trunk cavities and callus healing of trunk wounds. Each indicator was assessed in five-point scale, and in the end, the common index of quality was calculated. The quality index achieved 9.33 points in the first and 10.33 in the second evaluation periods in the Nitra city and 2.66 at the both assessed periods in the comparable rural park. In the group of physiological indicators, chlorophyll a fluorescence marker and its Fv/Fm parameter were used. Within three repeating assessment during growing season (June, August and September, the average values reached Fv/Fm = 0.814 in the city and Fv/Fm = 0.829 in rural park. The results confirmed statistical significances between loaded city conditions and relatively clean rural locality. Used markers have shown as appropriate tools for growth response measurements of street trees in a changed urban environment.

  12. In situ effects of elevated CO 2 on chlorophyll fluorescences and chloroplast pigments of alpine plant

    Science.gov (United States)

    Thron, Ch.; Hahn, K.; Lütz, C.

    Alpine vegetation responds to elevated CO 2 with downward adjustment of photosynthesis. The experiments should show if doubling of ambient CO 2 reduces the maximum quantum yield and the chlorophylls thus altering the pigment composition of the thylakoid membranes in typical species of an alpine grassland ( Caricetum curvulae). The studies were part of a CO 2 enrichment experiment with open-top chambers in the Swiss Central Alps in 2 470 m altitude over a period of four years. The leaves of Carex curvula and Trifolium alpinum were analysed in situ under ambient (355 μl/l) or elevated (680 μl/l) CO 2 and at two different nutrient levels. In each vegetation period both species showed a tendency to lower ratios of variable to maximum fluorescence (F v/F m) in plants with elevated CO 2 treatment compared to the ambient variants. These reductions in F v/F m were statistically different only for Carex curvula in 1993 and 1995. CO 2 enrichment caused reductions of leaf pigment concentrations of 10-30% especially for Trifolium alpinum whereas Carex curvula was less affected. The lower pigment contents per leaf were probably due to reductions of thylakoid membranes. In most cases, the influences of elevated CO 2 or of nutrient treatments on pigment composition and primary photochemistry were very small. This indicates that the downward regulation begins at early stages in the photosynthetic process. Some changes of the photosynthetic apparatus are species-specific and possibly reflect different strategies of protective acclimation processes of alpine vegetation.

  13. Global Monitoring of Terrestrial Chlorophyll Fluorescence from Space: Status and Potential for Carbon Cycle Research

    Science.gov (United States)

    Guanter, L.; Koehler, P.; Walther, S.; Zhang, Y.; Joiner, J.; Frankenberg, C.

    2015-12-01

    Gross primary production (GPP), or the amount of atmospheric CO2 fixed by vegetation through photosynthesis, represents the largest carbon flux between terrestrial ecosystems and the atmosphere. Despite its importance, large-scale estimates of GPP remain highly uncertain for some terrestrial ecosystems. In this context, measurements of sun-induced chlorophyll fluorescence (SIF), which is emitted in the 650-850nm spectral range by the photosynthetic apparatus of green plants, have the potential to provide a new view on vegetation photosynthesis. Global monitoring of SIF from space have been achieved in the last years by means of a number of atmospheric spectrometers, which have turned out to provide the necessary spectral and radiometric sensitivity for SIF retrieval. The first global measurements of SIF were achieved in 2011 from spectra acquired by the Japanese GOSAT mission. This breakthorugh was followed by retrievals from the Global Ozone Monitoring Experiment-2 (GOME-2) instruments onboard MetOp-A and MetOp-B, which enable a continuous spatial sampling, and lately from ENVISAT/SCIAMACHY. This observational scenario is completed by the first SIF data from the NASA-JPL OCO-2 mission (launched in July 2014) and the upcoming Copernicus' Sentinel 5-Precursor to be launched by early 2016. OCO-2 and TROPOMI offer the possibility of monitoring SIF globally with a 100-fold improvement in spatial and temporal resolution with respect to GOSAT, GOME-2 and SCIAMACHY.In this contribution, we will provide an overview of global SIF monitoring and will illustrate the potential of SIF data to improve our knowledge of vegetation photosynthesis and GPP at the synoptic scale. We will show examples of ongoing research exploiting SIF data for an improved monitoring of photosynthetic activity at different ecosystems, highlighting the usefulness of SIF to constrain estimates of CO2 uptake by vegetation through photosynthesis.

  14. A novel system for evaluating drought-cold tolerance of grapevines using chlorophyll fluorescence.

    Science.gov (United States)

    Su, Lingye; Dai, Zhanwu; Li, Shaohua; Xin, Haiping

    2015-03-11

    Grape production in continental climatic regions suffers from the combination of drought and cold stresses during winter. Developing a reliable system to simulate combined drought-cold stress and to determine physiological responses and regulatory mechanisms is important. Evaluating tolerance to combined stress at germplasm level is crucial to select parents for breeding grapevines. In the present study, two species, namely, Vitis amurensis and V. vinifera cv. 'Muscat Hamburg', were used to develop a reliable system for evaluating their tolerance to drought-cold stress. This system used tissue -cultured grapevine plants, 6% PEG solution, and gradient cooling mode to simulate drought-cold stress. V. amurensis had a significantly lower LT50 value (the temperature of 50% electrolyte leakage) than 'Muscat Hamburg' during simulated drought-cold stress. Thus, the former had higher tolerance than the latter to drought-cold stress based on electrolyte leakage (EL) measurements. Moreover, the chlorophyll fluorescence responses of V. amurensis and 'Muscat Hamburg' were also analyzed under drought-cold stress. The maximum photochemical quantum yield of PS II (Fv/Fm) exhibited a significant linear correlationship with EL. The relationship of EL with Fv/Fm in the other four genotypes of grapevines under drought-cold stress was also detected. A novel LT50 estimation model was established, and the LT50 values can be well calculated based on Fv/Fm in replacement of EL measurement. The Fv/Fm-based model exhibits good reliability for evaluating the tolerance of different grapevine genotypes to drought-cold stress.

  15. Consistency Between Sun-Induced Chlorophyll Fluorescence and Gross Primary Production of Vegetation in North America

    Science.gov (United States)

    Zhang, Yao; Xiao, Xiangming; Jin, Cui; Dong, Jinwei; Zhou, Sha; Wagle, Pradeep; Joiner, Joanna; Guanter, Luis; Zhang, Yongguang; Zhang , Geli; hide

    2016-01-01

    Accurate estimation of the gross primary production (GPP) of terrestrial ecosystems is vital for a better understanding of the spatial-temporal patterns of the global carbon cycle. In this study,we estimate GPP in North America (NA) using the satellite-based Vegetation Photosynthesis Model (VPM), MODIS (Moderate Resolution Imaging Spectrometer) images at 8-day temporal and 500 meter spatial resolutions, and NCEP-NARR (National Center for Environmental Prediction-North America Regional Reanalysis) climate data. The simulated GPP (GPP (sub VPM)) agrees well with the flux tower derived GPP (GPPEC) at 39 AmeriFlux sites (155 site-years). The GPP (sub VPM) in 2010 is spatially aggregated to 0.5 by 0.5-degree grid cells and then compared with sun-induced chlorophyll fluorescence (SIF) data from Global Ozone Monitoring Instrument 2 (GOME-2), which is directly related to vegetation photosynthesis. Spatial distribution and seasonal dynamics of GPP (sub VPM) and GOME-2 SIF show good consistency. At the biome scale, GPP (sub VPM) and SIF shows strong linear relationships (R (sup 2) is greater than 0.95) and small variations in regression slopes ((4.60-5.55 grams Carbon per square meter per day) divided by (milliwatts per square meter per nanometer per square radian)). The total annual GPP (sub VPM) in NA in 2010 is approximately 13.53 petagrams Carbon per year, which accounts for approximately 11.0 percent of the global terrestrial GPP and is within the range of annual GPP estimates from six other process-based and data-driven models (11.35-22.23 petagrams Carbon per year). Among the seven models, some models did not capture the spatial pattern of GOME-2 SIF data at annual scale, especially in Midwest cropland region. The results from this study demonstrate the reliable performance of VPM at the continental scale, and the potential of SIF data being used as a benchmark to compare with GPP models.

  16. Changes in chlorophyll content and fluorescence and fruit yield contributing traits in different genotypes of strawberry (Fragaria x ananassa DUCH.

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    Elżbieta Kaczmarska

    2014-01-01

    Full Text Available Analysis of changes in chlorophyll fluorescence parameters in strawberry leaves was based on a field experiment performed in the years 2009–2010. Ten genotypes including 5 cultivars: ‘Kent’, ‘Teresa’, ‘Senga Sengana’, ‘Chandler’ and the breeding clone 1387 as well as their inbred progeny, were the object of the study. During the experiment the following indicators were evaluated: chlorophyll a and b content in fresh leaf mass as well as fluorescence parameters: minimum (F0 and maximum fluorescence yield (Fm, photochemical efficiency of PS II (Fv/Fm, actual quantum yield of PSII photochemistry (Y, minimum (F0’ and maximum efficiency of fluorescence (Fm’ in the light, coefficient of photochemical (qP and non-photo- chemical (qN fluorescence quenching. In this work, we also examined the effect of repeated inbreeding on strawberry fruit yield and yield components. The analysis of changes of these parameters showed that inbreeding caused a reaction in all tested cultivars. In all inbred progeny, chlorophyll a and b content decreased compared to the cultivars. Generally, the photoche- mical efficiency of photosystem II (Fv/Fm and the parameter ΔF/ Fm’ were not affected by strong inbreeding. In analyzing the values of the coefficients qP and qN, it has been observed that changes in their values depend on the sensitivity of the examined genotypes to self-pollination. The functioning of PS II is the most sensitive indicator of the effect of various factors on plants and is useful, among others, in breeding to select plants with a required genotype. The yield – determining features such as: fruit yield per plant, weight of single fruit, number of fruit per plant and weight of leaves per plant in S3 generation, were lower as compared with parental forms.

  17. Features of chlorophyll fluorescence transients can be used to investigate low temperature induced effects on photosystem II of algal lichens from polar regions

    OpenAIRE

    Mishra Anamika; Hájek Josef; Tuháčková Tereza; Barták Miloš; Mishra Kumud Bandhu

    2015-01-01

    Chlorophyll fluorescence is an effective tool for investigating characteristics of any photosynthesizing organisms and its responses due to different stressors. Here, we have studied a short-term temperature response on three Antarctic green algal lichen species: Umbilicaria antarctica, Xanthoria elegans, and Rhizoplaca melanophtalma. We measured slow chlorophyll fluorescence transients in these Antarctic lichen species during slowely cooling of thallus temperature from 20°C to 5, 0 and -5°C ...

  18. Improving the modeling of the seasonal carbon cycle of the boreal forest with chlorophyll fluorescence measurements

    Science.gov (United States)

    Thum, Tea; Aalto, Tuula; Aurela, Mika; Laurila, Tuomas; Zaehle, Sönke

    2014-05-01

    The boreal ecosystems are characterized a very strong seasonal cycle and they are very sensitive to the climatic variables. The vegetation's deep wintertime dormancy requires a long recovery time during spring before the plants reach their full photosynthetic capacity. During this recovery time the plants are highly susceptible the night frosts. The transition period is different during spring and autumn for the evergreen plants. During spring there is plenty of light, but cold air temperatures inhibit the photosynthesis. The plants therefore experience to high stress levels, as they need to protect their photosynthetic apparatus from intense light. In autumn the air temperature and light level decrease more concurrently. To have a realistic presentation of the carbon cycle in boreal forests it is important to have these characteristics properly modeled, so that also the implications of changing seasonality under climate change can be more reliably predicted. In this study, we focus on the CO2 exchange of a Scots pine forest Sodankylä located in Finnish Lapland, 100 km north from the Arctic Circle. Micrometeorological flux measurements provide information about the exchanges of carbon, energy and water between atmosphere and vegetation. To complement these fluxes, we use dark-adapted chlorophyll fluorescence (CF) measurements, which is an optical measurement and tracks the development of the photosynthetic capacity. These two approaches combined together are very useful when we want to improve the modeling of the forest's CO2 exchange. We used two models that describe the photosynthesis with the biochemical model of Farquhar et al. The FMI-CANOPY is a canopy level model that is feasible to use in parameter estimation. We used the CF measurements of Fv/Fm, that is a measure of the maximum photosynthetic capacity, to include a seasonal development in the base rate of the maximum carboxylation rate (Vc(max)) in FMI-CANOPY. The simulation results matched the

  19. An Automated Comparative Observation System for Sun-Induced Chlorophyll Fluorescence of Vegetation Canopies

    Directory of Open Access Journals (Sweden)

    Xijia Zhou

    2016-05-01

    Full Text Available Detecting sun-induced chlorophyll fluorescence (SIF offers a new approach for remote sensing photosynthesis. However, to analyse the response characteristics of SIF under different stress states, a long-term time-series comparative observation of vegetation under different stress states must be carried out at the canopy scale, such that the similarities and differences in SIF change law can be summarized under different time scales. A continuous comparative observation system for vegetation canopy SIF is designed in this study. The system, which is based on a high-resolution spectrometer and an optical multiplexer, can achieve comparative observation of multiple targets. To simultaneously measure the commonly used vegetation index and SIF in the O2-A and O2-B atmospheric absorption bands, the following parameters are used: a spectral range of 475.9 to 862.2 nm, a spectral resolution of approximately 0.9 nm, a spectral sampling interval of approximately 0.4 nm, and the signal-to-noise ratio (SNR can be as high as 1000:1. To obtain data for both the upward radiance of the vegetation canopy and downward irradiance data with a high SNR in relatively short time intervals, the single-step integration time optimization algorithm is proposed. To optimize the extraction accuracy of SIF, the FluorMOD model is used to simulate sets of data according to the spectral resolution, spectral sampling interval and SNR of the spectrometer in this continuous observation system. These data sets are used to determine the best parameters of Fraunhofer Line Depth (FLD, Three FLD (3FLD and the spectral fitting method (SFM, and 3FLD and SFM are confirmed to be suitable for extracting SIF from the spectral measurements. This system has been used to observe the SIF values in O2-A and O2-B absorption bands and some commonly used vegetation index from sweet potato and bare land, the result of which shows: (1 the daily variation trend of SIF value of sweet potato leaves is

  20. Spectral reflectance, chlorophyll fluorescence and virological investigations of tobacco plants (Nicotiana tabacum L.) infected with Tobacco mosaic virus (TMV)

    Science.gov (United States)

    Krezhova, Dora; Hristova, Dimitrina; Iliev, Ilko; Yanev, Tony

    Application of multispectral remote sensing techniques to plant condition monitoring has been adopted for various purposes. Remote sensing is a reliable tool for detecting signs of vege-tation stress and diseases. Spectral reflectance and chlorophyll fluorescence are functions of tissue optical properties and biological status of the plants, and illumination conditions. The mean reflectance spectrum depends on the relative composition of all the pigments in the leaf including chlorophylls, carotenoids etc. Chlorophyll fluorescence results from the primary re-actions of photosynthesis and during the last decade it finds widening application as a means for revelation of stress and diseases. The changes in chlorophyll function take place before the alteration in chlorophyll content to occur so that changes in the fluorescence signal arise before any visible signs are apparent. The aim of our investigations was to study the development and spreading out of a viral infection on the leaves of two cultivars tobacco plants (Nicotiana tabacum L.) infected with Tobacco mosaic virus (TMV). We applied two remote sensing tech-niques (spectral reflectance and chlorophyll fluorescence measurements) for evaluation of the changes in the optical properties of the plants in accordance to their physiological status. The serological analyses via the Double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) were made with appropriate kits (Leowe, Germany) for quantitative assessment of the concentration of viruses in the plants. The tobacco plants were grown in green house under controlled conditions. The first cultivar Nevrocop 1146 is known as resistive to the TMV, i.e. it shows hypersensitive response. The second cultivar named Krumovgrad is normally sen-sitive to the TMV. At growth stage 4-6 expanded leaf, up to one leaf from 20 plants for each cultivar were inoculated with TMV. The leaves opposite to the infected ones formed the group of control (untreated) leaves. The

  1. Atrazine and Methyl Viologen Effects on Chlorophyll-a Fluorescence Revisited-Implications in Photosystems Emission and Ecotoxicity Assessment.

    Science.gov (United States)

    Iriel, Analia; Novo, Johanna M; Cordon, Gabriela B; Lagorio, María G

    2014-01-01

    In this work, we use the effect of herbicides that affect the photosynthetic chain at defined sites in the photosynthetic reaction steps to derive information about the fluorescence emission of photosystems. The interpretation of spectral data from treated and control plants, after correction for light reabsorption processes, allowed us to elucidate current controversies in the subject. Results were compatible with the fact that a nonnegligible Photosystem I contribution to chlorophyll fluorescence in plants at room temperature does exist. In another aspect, variable and nonvariable chlorophyll fluorescence were comparatively tested as bioindicators for detection of both herbicides in aquatic environment. Both methodologies were appropriate tools for this purpose. However, they showed better sensitivity for pollutants disconnecting Photosystem II-Photosystem I by blocking the electron transport between them as Atrazine. Specifically, changes in the (experimental and corrected by light reabsorption) red to far red fluorescence ratio, in the maximum photochemical quantum yield and in the quantum efficiency of Photosytem II for increasing concentrations of herbicides have been measured and compared. The most sensitive bioindicator for both herbicides was the quantum efficiency of Photosystem II. © 2013 The American Society of Photobiology.

  2. Three types of the concentration dependence of the red and far-red chlorophyll a fluorescence ratio

    Science.gov (United States)

    Zavoruev, Valerii; Zavorueva, Elena

    2003-04-01

    In this paper the dependence of the F682/F734 on the concentration in plants, grown under continuous light and natural photoperiod is studied. For natural photoperiod the duration of light for all probes was the same, as since leaves with different colors are selected at a time. It is shown, the dependence of the F682/F734 ratio on chlorophyll concentration in plant, grown under high-intensity continuous is described by a parabolic function and under intermittent light - exponential function. Third type of concentration dependence of the parameter F682/F734 was obtained in leaves of poplar in the process of vegetation under study of fluorescence and pigment characteristics. The dependence has complicated character and known functions cannot describe it. It is concluded, that all known dependences of the F682/F734 ratio on concentration of chlorophyll to this moment are used to concrete conditions of growth of plants and the method of probes choice for measurement. Now the universe function, connecting the relation between red and far-red fluorescence with chlorophyll content, is not existed.

  3. Remote Sensing of chlorophyll fluorescence and the impact of clouds on the retrival

    Science.gov (United States)

    Köhler, Philipp; Guanter, Luis; Frankenberg, Christian

    2013-04-01

    Remote sensing of sun-induced chlorophyll fluorescence (SIF) is a new, alternative option to gain information about terrestrial photosynthesis and CO2 assimilation on a global scale. The SIF is an electromagnetic signal emitted in the aprox. 650-800 nm spectral window by the photosynthesis apparatus, and can therefore be considered as a direct indicator of plant biochemical processes. The general approach to measure SIF from space is the evaluation of the in-filling of solar Fraunhofer lines or atmospheric absorption bands by SIF. To distinguish the SIF signal from the total incoming radiance at the sensor, which is about 100 times more intense, is a challenge and high resolution measurements are required. The high spectral resolution (approx. 0.02 nm) of the Fourier Transform Spectrometer (FTS) on-board the Greenhouse Gases Observing Satellite (GOSAT) enables such a measurement of SIF by means of the evaluation of the in-filling of solar Fraunhofer lines by SIF. The narrow wavelength band from 755 to 759 nm and around 770 nm can be used for this purpose because they are free from atmospheric absorption features, the solar radiation shows several Fraunhofer lines and the SIF values in this region are relatively high. A new SIF retrieval approach (GARLiC, for GOSAT Retrieval of cholorphyll fluorescence) will be presented in this contribution. This method is intended to simplify some of the assumptions of existing retrieval approaches without a loss in accuracy. The comparison of the GARLiC fluorescence retrievals with two state-of-the-art SIR retrieval methods such as those by Frankenberg et al. (2011) and Guanter et al. (2012) from GOSAT data shows corresponding and feasible results. In addition to the basics of SIF remote sensing, this contribution will assess the effect of clouds in the retrieval. To do this, the SIF retrieval has been coupled to a cloud optical thickness (COT) retrieval algorithm adapted to GOSAT-FTS O2A-band measurements, so that SIF and COT

  4. The Chlorophyll a Fluorescence Modulated by All-Trans-β-Carotene in the Process of Photosystem II

    Directory of Open Access Journals (Sweden)

    Tianyu Li

    2016-06-01

    Full Text Available Modulating the chlorophyll a (Chl-a fluorescence by all-trans-β-Carotene (β-Car in the polarity and non-polarity solutions was investigated. The fluorescence intensity of Chl-a decreased as the concentration of β-Car increased. The excited electronic levels of Chl-a and β-Car became much closer owing to the solvent effect, which led to the electron transfer between both two molecules. A electron-separated pair Chl−·Chl+ that is not luminous was formed due to electron transfer. The solution of Chl-a and β-car in C3H6O was similar to the internal environment of chloroplast. We conclude that the polar solvent is good for the fluorescent modulation in photosystem II.

  5. Diurnal and Directional Responses of Chlorophyll Fluorescence and the PRI in a Cornfield

    Science.gov (United States)

    Middleton, Elizabeth; Cheng, Y. B.; Corp, L.; Campbell, P.; Kustas, W.

    2010-01-01

    Determining the health and vigor of vegetation using high spectral resolution remote sensing is an important goal which has application to monitoring agriculture and ecosystem productivity and carbon exchange. Two spectral indices used to assess whether vegetation is performing near-optimally or exhibiting symptoms of environmental stress (e.g., drought or nutrient deficiency, non-optimal temperatures, etc.) are the Photochemical Reflectance Index (PRI) and solar-induced red and far-red Chlorophyll Fluorescence (Fs). Both the PRI and Fs capture the dynamics of photoprotection mechanisms within green foliage: the PRI is based on the association of the reflected radiation in the green spectrum with the xanthophyll cycle, whereas Fs measures the emitted radiation in the red and far-red spectrum. Fs was determined from retrievals in the atmospheric oxygen absorption features centered at 688 and 760 nm using a modified Fraunhofer Line Depth (FLD) method. We previously demonstrated diurnal and seasonal PRI differences for sunlit vs. shaded foliage in a conifer forest canopy, as expressed in the hotspot and darkspot of the Bidirectional Reflectance Function (BRF). In a USDA-ARS experimental field site located in Beltsville, MD, USA, measurements were acquired over a corn crop from a nadir view in 2008 with an ASD FieldSpec Pro (Analytical Spectral Devices, Inc., Boulder, CO, USA) to study the behavior of the PRI for sunlit and shaded foliage as captured in reflectance variations associated with the BRF, in a I m tall canopy in the vegetative growth stage. Those observations were compared to simulations obtained from two radiative transfer models. Measurements were then acquired to examine whether the PRI and Fs were influenced by view zenith and azimuth geometries at different times of day. Those measurements were made in 2010 with the Ocean Optics USB4000 Miniature Fiber Optic Spectrometer (Ocean Optics Inc., Dunedin, Florida, USA) at several times during the day on

  6. Chlorophyll Fluorescence Is a Better Proxy for Sunlit Leaf Than Total Canopy Photosynthesis

    Science.gov (United States)

    Chen, J. M.; Wang, Z.; Zhang, F.; Mo, G.

    2015-12-01

    Chlorophyll fluorescence (CF) results from non-photochemical quenching during plant photosynthesis under excessive radiation. We explore the relationship between gross primary productivity (GPP) and CF using a process ecosystem model, which separates a vegetation canopy into sunlit and shaded leaf groups and simulates the total canopy GPP as the sum of sunlit and shaded leaf GPP. Using GOME-2 and GOSAT data acquired in 2010 over the global land surface, we found that measured CF signals gridded in 1 degree resolution are well correlated with simulated total GPP and its sunlit and shaded components, but the correlation coefficients (R) are largest for the sunlit GPP and smallest for shaded GPP. The seasonal R2 values vary from 0.57 to 0.74, 0.58 to 0.71, and 0.48 to 0.56 for sunlit, total and shaded GPP, respectively. The significance levels for these correlations are all greater than pleaves. The significant correlation between measured canopy-level CF and the shaded GPP is likely due to the correlation between shaded and sunlit GPP as both increase with leaf area index. Our simulation confirms the validity of using canopy-level CF measurements to assess the total GPP as the first approximation, although these measurements are a consistently better indicator of sunlit GPP than total GPP. In previous studies, the R2 values for the correlation between CF and total GPP were found to range from 0.76 to 0.88, 0.56 to 0.78, and 0.57 to 0.77 for MPI-BGC, MODIS and CASA model results, respectively. These values are similar or larger than those for sunlit GPP simulated in our study, but are considerably larger than those for total GPP in our study because the correlation for total GPP is contaminated by the inclusion of shaded GPP. All these three models use canopy total light use efficiency without considering the differences between sunlit and shaded leaves, and therefore they mostly capture spatio-temporal variations in sunlit GPP. We therefore argue that solar

  7. Genetic variability and heritability of chlorophyll a fluorescence parameters in Scots pine (Pinus sylvestris L.).

    Science.gov (United States)

    Čepl, Jaroslav; Holá, Dana; Stejskal, Jan; Korecký, Jiří; Kočová, Marie; Lhotáková, Zuzana; Tomášková, Ivana; Palovská, Markéta; Rothová, Olga; Whetten, Ross W; Kaňák, Jan; Albrechtová, Jana; Lstibůrek, Milan

    2016-07-01

    Current knowledge of the genetic mechanisms underlying the inheritance of photosynthetic activity in forest trees is generally limited, yet it is essential both for various practical forestry purposes and for better understanding of broader evolutionary mechanisms. In this study, we investigated genetic variation underlying selected chlorophyll a fluorescence (ChlF) parameters in structured populations of Scots pine (Pinus sylvestris L.) grown on two sites under non-stress conditions. These parameters were derived from the OJIP part of the ChlF kinetics curve and characterize individual parts of primary photosynthetic processes associated, for example, with the exciton trapping by light-harvesting antennae, energy utilization in photosystem II (PSII) reaction centers (RCs) and its transfer further down the photosynthetic electron-transport chain. An additive relationship matrix was estimated based on pedigree reconstruction, utilizing a set of highly polymorphic single sequence repeat markers. Variance decomposition was conducted using the animal genetic evaluation mixed-linear model. The majority of ChlF parameters in the analyzed pine populations showed significant additive genetic variation. Statistically significant heritability estimates were obtained for most ChlF indices, with the exception of DI0/RC, φD0 and φP0 (Fv/Fm) parameters. Estimated heritabilities varied around the value of 0.15 with the maximal value of 0.23 in the ET0/RC parameter, which indicates electron-transport flux from QA to QB per PSII RC. No significant correlation was found between these indices and selected growth traits. Moreover, no genotype × environment interaction (G × E) was detected, i.e., no differences in genotypes' performance between sites. The absence of significant G × E in our study is interesting, given the relatively low heritability found for the majority of parameters analyzed. Therefore, we infer that polygenic variability of these indices is

  8. Chlorophyll fluorescence protocol for quick detection of triazinone resistant Chenopodium album L.

    Science.gov (United States)

    Mechant, E; De Marez, T; Aper, J; Bulcke, R

    2010-01-01

    Sugar beet growers in Europe are more often confronted with an unsatisfactory control of Chenopodium album L. (fat-hen), possibly due to the presence of a triazinone resistant biotype. So far, two mutations on the psbA-gene, i.e. Ser264-Gly and Ala251-Val, are known to cause resistance in C. album to the photosystem II-inhibiting triazinones metamitron, a key herbicide in sugar beet, and metribuzin. The Ser264-Gly biotype, cross-resistant to many other photosystem II-inhibitors like the triazines atrazine and terbuthylazine, is most common. The second resistant C. album biotype, recorded in Sweden, is highly resistant to triazinones but only slightly cross-resistant to terbuthylazine. Since farmers should adapt their weed control strategy when a resistant biotype is present, a quick and cheap detection method is needed. Therefore, through trial and error, a protocol for detection with chlorophyll fluorescence measurements was developed and put to the test. First, C. album leaves were incubated in herbicide solution (i.e. 0 microM, 25 microM metribuzin, 200 microM metamitron or 25 microM terbuthylazine) during three hours under natural light. After 30 minutes of dark adaptation, photosynthesis yield was measured with Pocket PEA (Hansatech Instruments). In Leaves from sensitive C. album, herbicide treatment reduces photosynthesis yield due to inhibition of photosynthesis at photosystem II. This results in a difference of photosynthesis yield between the untreated control and herbicide treatment. Based on the relative photosynthesis yield (as a percentage of untreated), a classification rule was formulated: C. album is classified as sensitive when its relative photosynthesis yield is less than 90%, otherwise it is resistant. While metribuzin, and to a lesser extent, metamitron treatment allowed a quick detection of triazinone resistant C. album, terbuthylazine treatment was able to distinguish the Ser264-Gly from the Ala251-Val biotype. As a final test, 265 plants

  9. Led induced chlorophyll fluorescence transient imager for measurements of health and stress status of whole plants

    NARCIS (Netherlands)

    Jalink, H.; Schoor, van der R.

    2011-01-01

    We have developed LED (light emitting diode) induced fluorescence transient imaging instrumentation to image the plant health/stress status by calculation of two images: Fv/Fm (variable fluorescence over saturation level of fluorescence) and the time response, tTR, of the fluorescence time curve.

  10. Investigation of Leaf Diseases and Estimation of Chlorophyll Concentration in Seven Barley Varieties Using Fluorescence and Hyperspectral Indices

    Directory of Open Access Journals (Sweden)

    Kang Yu

    2013-12-01

    Full Text Available Leaf diseases, such as powdery mildew and leaf rust, frequently infect barley plants and severely affect the economic value of malting barley. Early detection of barley diseases would facilitate the timely application of fungicides. In a field experiment, we investigated the performance of fluorescence and reflectance indices on (1 detecting barley disease risks when no fungicide is applied and (2 estimating leaf chlorophyll concentration (LCC. Leaf fluorescence and canopy reflectance were weekly measured by a portable fluorescence sensor and spectroradiometer, respectively. Results showed that vegetation indices recorded at canopy level performed well for the early detection of slightly-diseased plants. The combined reflectance index, MCARI/TCARI, yielded the best discrimination between healthy and diseased plants across seven barley varieties. The blue to far-red fluorescence ratio (BFRR_UV and OSAVI were the best fluorescence and reflectance indices for estimating LCC, respectively, yielding R2 of 0.72 and 0.79. Partial least squares (PLS and support vector machines (SVM regression models further improved the use of fluorescence signals for the estimation of LCC, yielding R2 of 0.81 and 0.84, respectively. Our results demonstrate that non-destructive spectral measurements are able to detect mild disease symptoms before significant losses in LCC due to diseases under natural conditions.

  11. [Effects of NaCl stress on photosynthesis characteristics and fast chlorophyll fluorescence induction dynamics of Pistacia chinensis leaves].

    Science.gov (United States)

    Li, Xu-Xin; Liu, Bing-Xiang; Guo, Zhi-Tao; Chang, Yue-Xia; He, Lei; Chen, Fang; Lu, Bing-She

    2013-09-01

    By using fast chlorophyll fluorescence induction dynamics analysis technique (JIP-test), this paper studied the photosynthesis characteristics and fast chlorophyll fluorescence induction dynamics of 1-year old Pistacia chinensis seedlings under the stress of NaCl at the concentrations 0% (CK), 0.15%, 0.3%, 0.45%, and 0.6%. With the increasing concentration of NaCl, the contents of Chl a, Chl b, and Chl (a+b) in the seedlings leaves decreased, the Chl a/b ratio decreased after an initial increase, and the carotenoid content increased. The net photosynthetic rate (P(n)) and stomatal conductance (g(s)) decreased gradually with increasing NaCl concentration. The decrease of P(n) was mainly attributed to the stomatal limitation when the NaCl concentration was lower than 0.3%, and to the non-stomatal limitation when the NaCl concentration was higher than 0.3%. The trapped energy flux per RC (TR0/CS0), electron transport flux per RC (ET0/CS0), density of RCs (RC/CS0), and yield or flux ratio (psi(0) or phi(E0)) decreased, but the absorption flux per CS (ABS/CS0) and the K phase (W(k)) and J phase (V) in the O-J-I-P chlorophyll fluorescence induction curves increased distinctly, indicating that NaCl stress damaged the leaf oxygen-evolving complex (OEC), donor sides, and PS II reaction centers. When the NaCl concentration reached 0.3%, the maximum photochemical efficiency (F(v)/F(m)) and performance index (PI(ABS)) decreased 17.7% and 36.6%, respectively, as compared with the control.

  12. A retrieval algorithm to evaluate the Photosystem I and Photosystem II spectral contributions to leaf chlorophyll fluorescence at physiological temperatures.

    Science.gov (United States)

    Palombi, Lorenzo; Cecchi, Giovanna; Lognoli, David; Raimondi, Valentina; Toci, Guido; Agati, Giovanni

    2011-09-01

    A new computational procedure to resolve the contribution of Photosystem I (PSI) and Photosystem II (PSII) to the leaf chlorophyll fluorescence emission spectra at room temperature has been developed. It is based on the Principal Component Analysis (PCA) of the leaf fluorescence emission spectra measured during the OI photochemical phase of fluorescence induction kinetics. During this phase, we can assume that only two spectral components are present, one of which is constant (PSI) and the other variable in intensity (PSII). Application of the PCA method to the measured fluorescence emission spectra of Ficus benjamina L. evidences that the temporal variation in the spectra can be ascribed to a single spectral component (the first principal component extracted by PCA), which can be considered to be a good approximation of the PSII fluorescence emission spectrum. The PSI fluorescence emission spectrum was deduced by difference between measured spectra and the first principal component. A single-band spectrum for the PSI fluorescence emission, peaked at about 735 nm, and a 2-band spectrum with maxima at 685 and 740 nm for the PSII were obtained. A linear combination of only these two spectral shapes produced a good fit for any measured emission spectrum of the leaf under investigation and can be used to obtain the fluorescence emission contributions of photosystems under different conditions. With the use of our approach, the dynamics of energy distribution between the two photosystems, such as state transition, can be monitored in vivo, directly at physiological temperatures. Separation of the PSI and PSII emission components can improve the understanding of the fluorescence signal changes induced by environmental factors or stress conditions on plants.

  13. Time sequence of the damage to the acceptor and donor sides of photosystem II by UV-B radiation as evaluated by chlorophyll a fluorescence

    NARCIS (Netherlands)

    Rensen, van J.J.S.; Vredenberg, W.J.; Rodrigues, G.C.

    2007-01-01

    The effects of ultraviolet-B (UV-B) radiation on photosystem II (PS II) were studied in leaves of Chenopodium album. After the treatment with UV-B the damage was estimated using chlorophyll a fluorescence techniques. Measurements of modulated fluorescence using a pulse amplitude modulated

  14. Chlorophyll fluorescence analysis revealed essential roles of FtsH11 protease in regulation of the adaptive responses of photosynthetic systems to high temperature.

    Science.gov (United States)

    Chen, Junping; Burke, John J; Xin, Zhanguo

    2018-01-10

    Photosynthetic systems are known to be sensitive to high temperature stress. To maintain a relatively "normal" level of photosynthetic activities, plants employ a variety of adaptive mechanisms in response to environmental temperature fluctuations. Previously, we reported that the chloroplast-targeted AtFtsH11 protease played an essential role for Arabidopsis plants to survive at high temperatures and to maintain normal photosynthetic efficiency at moderately elevated temperature. To investigate the factors contributing to the photosynthetic changes in FtsH11 mutant, we performed detailed chlorophyll fluorescence analyses of dark-adapted mutant plants and compared them to Col-0 WT plants under normal, two moderate high temperatures, and a high light conditions. We found that mutation of FtsH11 gene caused significant decreases in photosynthetic efficiency of photosystems when environmental temperature raised above optimal. Under moderately high temperatures, the FtsH11 mutant showed significant 1) decreases in electron transfer rates of photosystem II (PSII) and photosystem I (PSI), 2) decreases in photosynthetic capabilities of PSII and PSI, 3) increases in non-photochemical quenching, and a host of other chlorophyll fluorescence parameter changes. We also found that the degrees of these negative changes for utilizing the absorbed light energy for photosynthesis in FtsH11 mutant were correlated with the level and duration of the heat treatments. For plants grown under normal temperature and subjected to the high light treatment, no significant difference in chlorophyll fluorescence parameters was found between the FtsH11 mutant and Col-0 WT plants. The results of this study show that AtFtsH11 is essential for normal photosynthetic function under moderately elevated temperatures. The results also suggest that the network mediated by AtFtsH11 protease plays critical roles for maintaining the thermostability and possibly structural integrity of both photosystems

  15. Leaf gas exchange and chlorophyll a fluorescence in wheat plants supplied with silicon and infected with Pyricularia oryzae.

    Science.gov (United States)

    Perez, Carlos Eduardo Aucique; Rodrigues, Fabrício Ávila; Moreira, Wiler Ribas; DaMatta, Fábio Murilo

    2014-02-01

    This study investigated the effect of silicon (Si) on the photosynthetic gas exchange parameters (net CO2 assimilation rate [A], stomatal conductance to water vapor [gs], internal CO2 concentration [Ci], and transpiration rate [E]) and chlorophyll fluorescence a parameters (maximum quantum quenching [Fv/Fm and Fv'/Fm'], photochemical [qP] and nonphotochemical [NPQ] quenching coefficients, and electron transport rate [ETR]) in wheat plants grown in a nutrient solution containing 0 mM (-Si) or 2 mM (+Si) Si and noninoculated or inoculated with Pyricularia oryzae. Blast severity decreased due to higher foliar Si concentration. For the inoculated +Si plants, A, gs, and E were significantly higher in contrast to the inoculated -Si plants. For the inoculated +Si plants, significant differences of Fv/Fm between the -Si and +Si plants occurred at 48, 96, and 120 h after inoculation (hai) and at 72, 96, and 120 hai for Fv'/Fm'. The Fv/Fm and Fv'/Fm', in addition to total chlorophyll concentration (a + b) and the chlorophyll a/b ratio, significantly decreased in the -Si plants compared with the +Si plants. Significant differences between the -Si and +Si inoculated plants occurred for qP, NPQ, and ETR. The supply of Si contributed to decrease blast severity in addition to improving gas exchange performance and causing less dysfunction at the photochemical level.

  16. Detection of herbicide effects on pigment composition and PSII photochemistry in Helianthus annuus by Raman spectroscopy and chlorophyll a fluorescence

    Science.gov (United States)

    Vítek, Petr; Novotná, Kateřina; Hodaňová, Petra; Rapantová, Barbora; Klem, Karel

    2017-01-01

    The effects of herbicides from three mode-of-action groups - inhibitors of protoporphyrinogen oxidase (carfentrazone-ethyl), inhibitors of carotenoid biosynthesis (mesotrione, clomazone, and diflufenican), and inhibitors of acetolactate synthase (amidosulfuron) - were studied in sunflower plants (Helianthus annuus). Raman spectroscopy, chlorophyll fluorescence (ChlF) imaging, and UV screening of ChlF were combined to evaluate changes in pigment composition, photosystem II (PSII) photochemistry, and non-photochemical quenching in plant leaves 6 d after herbicide application. The Raman signals of phenolic compounds, carotenoids, and chlorophyll were evaluated and differences in their intensity ratios were observed. Strongly augmented relative content of phenolic compounds was observed in the case of amidosulfuron-treated plants, with a simultaneous decrease in the chlorophyll/carotenoid intensity ratio. The results were confirmed by in vivo measurement of flavonols using UV screening of ChlF. Herbicides from the group of carotenoid biosynthesis inhibitors significantly decreased both the maximum quantum efficiency of PSII and non-photochemical quenching as determined by ChlF. Resonance Raman imaging (mapping) data with high resolution (150,000-200,000 spectra) are presented, showing the distribution of carotenoids in H. annuus leaves treated by two of the herbicides acting as inhibitors of carotenoid biosynthesis (clomazone or diflufenican). Clear signs were observed that the treatment induced carotenoid depletion within sunflower leaves. The depletion spatial pattern registered differed depending on the type of herbicide applied.

  17. Comparison of chlorophyll in the Red Sea derived from MODIS-Aqua and in vivo fluorescence

    KAUST Repository

    Brewin, Robert J W

    2013-09-01

    The Red Sea is a unique marine environment but relatively unexplored. The only available long-term biological dataset at large spatial and temporal scales is remotely-sensed chlorophyll observations (an index of phytoplankton biomass) derived using satellite measurements of ocean colour. Yet such observations have rarely been compared with in situ data in the Red Sea. In this paper, satellite chlorophyll estimates in the Red Sea from the MODIS instrument onboard the Aqua satellite are compared with three recent cruises of in vivo fluorometric chlorophyll measurements taken in October 2008, March 2010 and September to October 2011. The performance of the standard NASA chlorophyll algorithm, and that of a new band-difference algorithm, is found to be comparable with other oligotrophic regions in the global ocean, supporting the use of satellite ocean colour in the Red Sea. However, given the unique environmental conditions of the study area, regional algorithms are likely to fare better and this is demonstrated through a simple adjustment to the band-difference algorithm. © 2013 Elsevier Inc.

  18. Genotypic response of detached leaves versus intact plants for chlorophyll fluorescence parameters under high temperature stress in wheat

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Fernández, Juan Olivares; Rosenqvist, Eva

    2014-01-01

    The genotypic response of wheat cultivars as affected by two methods of heat stress treatment (treatment of intact plants in growth chambers versus treatment of detached leaves in test tubes) in a temperature controlled water bath were compared to investigate how such different methods of heat...... treatment affect chlorophyll fluorescence parameters. A set of 41 spring wheat cultivars differing in their maximum photochemical efficiency of photosystem (PS) II (Fv/Fm) under heat stress conditions was used. These cultivars were previously evaluated based on the heat treatment of intact plants...... the fluorescence parameters. In contrast, heat induced reduction in the maximum photochemical efficiency of PSII of detached leaves occurred within 2h at 40°C and within 30min at 45°C, and the response was more pronounced than when intact plants were heat stressed for three days at 40°C. The proportion of total...

  19. An Integrative Observing and Modeling Approach for the Physiological Understanding of Sun-Induced Chlorophyll Fluorescence in Japan

    Science.gov (United States)

    Kobayashi, H.; Kato, T.; Saitoh, Y.; Noda, H.; Kikosaka, K.; Ichii, K.; Nasahara, K. N.

    2016-12-01

    Satellite-derived sun-induced chlorophyll fluorescence (SIF) is expected to provides a pathway to link leaf level photosynthesis to global GPP. Existing studies have stressed how well the satellite-derived SIF is correlated with the eddy covariance and/or modeled GPPs. There are some challenges in SIF interpretation because the satellite-derived SIF is a mixture of fluorescence emission from sunlit and shaded leaves and multiple scatterings of fluorescence within plant canopies. In this presentation, we show observation and modeling results around Japan and discuss how the integrative observing and modeling approach potentially overcomes the gaps in-between satellite SIF and photosynthesis reaction within leaves. We have analyzed ground-based SIF monitoring systems "Phenological Eye Network (PEN)". PEN covers several eddy flux sites in Japan and is equipped with spectroradiometer (MS-700) since 2003 (at an earliest site). The computed seasonal SIF variations in the different ecosystems show environmental dependency of SIF and GPP. Another ground-based system we are now developing is the vegetation lidar system named LIFS (Laser-Induced Fluorescence Spectrum), which can offer eco-physiological information of plants. LIFS is consisted of a pulsed UV (355 nm) laser, a telescope, a spectrometer/filter, and a gated image-intensified CCD detector. This system has been using to remotely monitor tree growth status, chlorophyll contents in leaves and so on. The physical and physiological theories are necessary for understanding the observed SIF under various environmental conditions. We have been developing leaf to plant canopy scale photosynthesis and SIF models as precise as possible. The developed model has been used to understand how the leaf-level SIF emission can be related to the canopy scale SIF, which enables to investigate the top of canopy SIF observed from ground-based and satellite-derived SIF measurements.

  20. Effects of water stress and light intensity on chlorophyll fluorescence parameters and pigments of Aloe vera L.

    Science.gov (United States)

    Hazrati, Saeid; Tahmasebi-Sarvestani, Zeinolabedin; Modarres-Sanavy, Seyed Ali Mohammad; Mokhtassi-Bidgoli, Ali; Nicola, Silvana

    2016-09-01

    Aloe vera L. is one of the most important medicinal plants in the world. In order to determine the effects of light intensity and water deficit stress on chlorophyll (Chl) fluorescence and pigments of A. vera, a split-plot in time experiment was laid out in a randomized complete block design with four replications in a research greenhouse. The factorial combination of three light intensities (50, 75 and 100% of sunlight) and four irrigation regimes (irrigation after depleting 20, 40, 60 and 80% of soil water content) were considered as main factors. Sampling time was considered as sub factor. The first, second and third samplings were performed 90, 180 and 270 days after imposing the treatments, respectively. The results demonstrated that the highest light intensity and the severe water stress decreased maximum fluorescence (Fm), variable fluorescence (Fv)/Fm, quantum yield of PSII photochemistry (ФPSII), Chl and photochemical quenching (qP) but increased non-photochemical quenching (NPQ), minimum fluorescence (F0) and Anthocyanin (Anth). Additionally, the highest Fm, Fv/Fm, ФPSII and qP and the lowest NPQ and F0 were observed when 50% of sunlight was blocked and irrigation was done after 40% soil water depletion. Irradiance of full sunlight and water deficit stress let to the photoinhibition of photosynthesis, as indicated by a reduced quantum yield of PSII, ФPSII, and qP, as well as higher NPQ. Thus, chlorophyll florescence measurements provide valuable physiological data. Close to half of total solar radiation and irrigation after depleting 40% of soil water content were selected as the most efficient treatments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Improvement of Photosynthesis by Sub1 QTL in Rice Under Submergence: Probed by Chlorophyll Fluorescence OJIP Transients

    Directory of Open Access Journals (Sweden)

    Panda Debabrata

    2011-09-01

    Full Text Available The influence of submergence on the photosynthetic activity in rice plants either possessing or not possessing Sub1 QTL i.e. Swarna and Swarna Sub1 cultivars (cv. were evaluated under simulated complete submergence. The leaf photosynthetic rate and stomatal conductance decreased in both the cv. during the progression of submergence as compared to control plant but significant varietal differences was observed after 1 day (d of submergence. Submergence also alters the photo-system (PS II activity, as reflected in a decrease in the values of Fo, Fm and the Fv/Fm ratio and degradation of chlorophyll, more in Swarna than that of Swarna Sub1. Under complete submergence the shape of the OJIP transient also changed in rice leaves with decrease in maximal fluorescence (P=Fm intensity, resulted lowering of variable fluorescence levels. The decrease was more pronounced in Swarna compared to the Swarna Sub1 cv. Thus, Swarna Sub1 improves photosynthetic activity showing more photosynthetic rate compared to Swarna under submergence because, of less degradation of chlorophyll, higher stomatal conductance, and efficient PS II activity.

  2. A statistical analysis of the freshness of postharvest leafy vegetables with application of water based on chlorophyll fluorescence measurement

    Directory of Open Access Journals (Sweden)

    Yichen Qiu

    2017-12-01

    Full Text Available Vegetable freshness is very important for both restaurant and home consumers. In market, sellers frequently apply water to leafy vegetables to make them not lose weight and look fresh; however, these vegetables may not be stored for a long time as they appear. After a time limit, they may be quickly rotten. It is thus meaningful to investigate early and simple detection tools to measure leafy vegetable freshness while they are frequently applied water in selling. In this work, three types of newly harvested leafy vegetables were bought from a local farmer market and stored in the air with room temperature and roots submerging in water. Chlorophyll a fluorescence (ChlF from the vegetables was measured each half a day for three days. The obtained ChlF data were analyzed statistically and the correlation of ChlF parameters and vegetable freshness/storage time was obtained. The k-mean classification was also performed. It is found that Fo, Fj, Fm/Fo, and Fv/Fm can be used as an early detection tool to differentiate the freshness of leafy vegetables on which water is constantly applied in storage without visible difference. Keywords: Vegetable freshness, Chlorophyll fluorescence, Food measurement

  3. Estimation of the effect of radionuclide contamination on Vicia sativa L. induction of chlorophyll fluorescence parameters using "Floratest" optical biosensor

    Science.gov (United States)

    Ruban, Yu.; Illienko, V.; Nesterova, N.; Pareniuk, O.; Shavanova, K.

    2017-12-01

    The presented research was aimed to determine the parameters of chlorophyll fluorescence (IChH) curve induction for Vicia sativa L. that were grown on radionuclide contaminated soils by using "Floratest" fluorometer. Plants were inoculated with 5 species of bacteria that might potentially block radionuclide uptake (Agrobacterium radiobacter IMBB-7246, Azotobacter chroococcum UKMB-6082, A. chroococcum UKMB-6003, Bacillus megaterium UKMB-5724, Rhizobium leguminosarum bv. viceae) and grown in sod-podzolic, chernozem and peat-bog soils, contaminated with 137Cs (4000±340 Bq/kg). As a result of research, it was determined that the most stressful factors for vetch plants are combination of soil radionuclide and presence of Bacillus megaterium UKM B-5724, as the number of inactive chlorophyll increased. In addition, the vetch plants significantly increased fixed level of fluorescence (Fst) under the influence of radioactive contamination in presence of Bacillus megaterium UKM B-5724, indicating inhibition of photosynthetic reactions. Other bacteria showed radioprotective properties in almost all types of soil.

  4. [Monitoring the chlorophyll fluorescence parameter Fv/Fm in compact corn based on different hyperspectral vegetation indices].

    Science.gov (United States)

    Tan, Chang-wei; Huang, Wen-jiang; Jin, Xiu-liang; Wang, Jun-chan; Tong, Lu; Wang, Ji-hua; Guo, Wen-shan

    2012-05-01

    In order to further assess the feasibility of monitoring the chlorophyll fluorescence parameter Fv/Fm in compact corn by hyperspectral remote sensing data, in the present study, hyperspectral vegetation indices from in-situ remote sensing measurements were utilized to monitor the chlorophyll fluorescence parameter Fv/Fm measured in the compact corn experiment. The relationships were analyzed between hyperspectral vegetation indices and Fv/Fm, and the monitoring models were established for Fv/Fm in the whole growth stages of compact corn. The results indicated that Fv/Fm was significantly correlated to the hyperspectral vegetation indices. Among them, structure-sensitive pigment index (SIPI) was the most sensitive remote sensing variable for monitoring Fv/Fm with correlation coefficient (r) of 0.88. The monitoring model of Fv/Fm was established on the base of SIPI, and the determination coefficients (r2) and the root mean square errors (RMSE) were 0.8126 and 0.082 respectively. The overall results suggest that hyperspectral vegetation indices can be potential indicators to monitor Fv/Fm during growth stages of compact corn.

  5. A Label-Free Microfluidic Biosensor for Activity Detection of Single Microalgae Cells Based on Chlorophyll Fluorescence

    Directory of Open Access Journals (Sweden)

    Junsheng Wang

    2013-11-01

    Full Text Available Detection of living microalgae cells is very important for ballast water treatment and analysis. Chlorophyll fluorescence is an indicator of photosynthetic activity and hence the living status of plant cells. In this paper, we developed a novel microfluidic biosensor system that can quickly and accurately detect the viability of single microalgae cells based on chlorophyll fluorescence. The system is composed of a laser diode as an excitation light source, a photodiode detector, a signal analysis circuit, and a microfluidic chip as a microalgae cell transportation platform. To demonstrate the utility of this system, six different living and dead algae samples (Karenia mikimotoi Hansen, Chlorella vulgaris, Nitzschia closterium, Platymonas subcordiformis, Pyramidomonas delicatula and Dunaliella salina were tested. The developed biosensor can distinguish clearly between the living microalgae cells and the dead microalgae cells. The smallest microalgae cells that can be detected by using this biosensor are 3 μm ones. Even smaller microalgae cells could be detected by increasing the excitation light power. The developed microfluidic biosensor has great potential for in situ ballast water analysis.

  6. Impact of Drought, Heat, and Their Combination on Chlorophyll Fluorescence and Yield of Wild Barley (Hordeum spontaneum

    Directory of Open Access Journals (Sweden)

    Christoph Jedmowski

    2015-01-01

    Full Text Available The impact of (long-term drought acclimation and (short-term heat stress and their combination on fast chlorophyll fluorescence induction curves (OJIP and grain yield was tested using pot-grown plants of wild barley (Hordeum spontaneum originating from Northern Egypt. Concerning agronomic traits, the main effect of drought was decreased biomass accumulation and grain yield, while heat specifically affected floral development. The treatments caused specific inhibitions of photosystem II (PSII functionality. While heat stressed plants showed a reduction of maximum quantum efficiency of PSII (φP0, an indication of effects on oxygen evolving complex (OEC functionality, and the connectivity of PSII units, these features were entirely missing in drought acclimated plants. Drought caused a reduction of the Performance Index (PIabs and of the relative amplitude of the IP-phase of the OJIP induction curve (ΔVIP. Individuals suffering from a combination of drought and heat showed a better ability to recover photosynthetic electron transport after the relief of stress in comparison to heat stressed plants. However, this improved capacity to recover was not accompanied by an increased grain yield. Thus, we conclude that chlorophyll fluorescence measurements provide valuable physiological data; however, their use in agronomic studies for the prediction of agronomic traits should be done with some precaution.

  7. Analysis of chlorophyll fluorescence spectra for the monitoring of Cd toxicity in a bio-energy crop (Jatropha curcas).

    Science.gov (United States)

    Marques, Marise Conceição; do Nascimento, Clístenes Williams Araújo

    2013-10-05

    The vegetation of metal-contaminated soils using non-edible crops can be a safe and economical technique for Cd immobilization and the remediation of contaminated sites. Jatropha (Jatropha curcas L.) exhibits a relative tolerance to heavy metals and potential for biofuel production. The study was performed to monitor the Cd-induced alterations in jatropha plants by X-ray chlorophyll fluorescence. The Cd effects on photosynthetic pigments, the mineral composition of plants, defense enzyme activity and soluble proteins were also studied. Plants were grown for 20days in a nutrient solution with five Cd contents: 5, 10, 20, 30 and 40μmolL(-1); a control with no Cd addition was also monitored. The analysis of the chlorophyll fluorescence spectra allowed detecting alterations caused by Cd toxicity in the jatropha plants. The mineral composition of the plants was affected by the Cd doses; however, the Fe and Mg contents were not significantly reduced, which most likely improved the effects on the contents of the photosynthetic pigments. Because of its relative tolerance to Cd, Jatropha curcas may be a promising species to revegetate Cd-contaminated sites. Considering the long period needed to phytoremediate soils, the combination of remediation with bioenergy production could be an attractive option. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Meta-analysis assessing potential of steady-state chlorophyll fluorescence for remote sensing detection of plant water, temperature and nitrogen stress

    Czech Academy of Sciences Publication Activity Database

    Ač, Alexander; Malenovský, Z.; Olejníčková, Julie; Gallé, A.; Rascher, U.; Mohammed, G.

    2015-01-01

    Roč. 168, oct (2015), s. 420-436 ISSN 0034-4257 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : steady-state chlorophyll fluorescence * passive sun-induced fluorescence * active laser-induced fluorescence * photosynthesis * stress * water * temperature * nitrogen * random-effects meta-analysis * FLEX satellite mission Subject RIV: EH - Ecology, Behaviour Impact factor: 5.881, year: 2015

  9. Fluorescence kinetic parameters and cyclic electron transport in guard cell chloroplasts of chlorophyll-deficient leaf tissues from variegated weeping fig (Ficus benjamina L.).

    Science.gov (United States)

    Lysenko, Vladimir

    2012-05-01

    Residual chlorophyll in chlorophyll-deficient (albino) areas of variegated leaves of Ficus benjamina originates from guard cell chloroplasts. Photosynthetic features of green and albino sectors of F. benjamina were studied by imaging the distribution of the fluorescence decrease ratio Rfd within a leaf calculated from maximum (Fm) and steady-state leaf chlorophyll fluorescence (Fs) at 690 and 740 nm. Local areas of albino sectors demonstrated an abnormally high Rfd(740)/Rfd(690) ratio. Fluorescence transients excited in albino sectors at red (640 and 690 nm) wavelengths showed an abrupt decrease of the Rfd values (0.4 and 0.1, correspondingly) as compared with those excited at blue wavelengths (1.7-2.4). This "Red Drop" was not observed for green sectors. Normal and chlorophyll-deficient leaf sectors of F. benjamina were also tested for linear and cyclic electron transport in thylakoids. The tests have been performed studying fluorescence at a steady-state phase with CO(2)-excess impulse feeding, photoacoustic signal generated by pulse light source at wavelengths selectively exciting PSI, fluorescence kinetics under anaerobiosis and fluorescence changes observed by dual-wavelength excitation method. The data obtained for albino sectors strongly suggest the possibility of a cyclic electron transport simultaneously occurring in guard cell thylakoids around photosystems I and II under blue light, whereas linear electron transport is absent or insufficient.

  10. Performance of a two-leaf light use efficiency model for mapping gross primary productivity against remotely sensed sun-induced chlorophyll fluorescence data.

    Science.gov (United States)

    Zan, Mei; Zhou, Yanlian; Ju, Weimin; Zhang, Yongguang; Zhang, Leiming; Liu, Yibo

    2018-02-01

    Estimating terrestrial gross primary production is an important task when studying the carbon cycle. In this study, the ability of a two-leaf light use efficiency model to simulate regional gross primary production in China was validated using satellite Global Ozone Monitoring Instrument - 2 sun-induced chlorophyll fluorescence data. The two-leaf light use efficiency model was used to estimate daily gross primary production in China's terrestrial ecosystems with 500-m resolution for the period from 2007 to 2014. Gross primary production simulated with the two-leaf light use efficiency model was resampled to a spatial resolution of 0.5° and then compared with sun-induced chlorophyll fluorescence. During the study period, sun-induced chlorophyll fluorescence and gross primary production simulated by the two-leaf light use efficiency model exhibited similar spatial and temporal patterns in China. The correlation coefficient between sun-induced chlorophyll fluorescence and monthly gross primary production simulated by the two-leaf light use efficiency model was significant (pproduction simulated by the two-leaf light use efficiency model were similar in spring and autumn in most vegetated regions, but dissimilar in winter and summer. The spatial variability of sun-induced chlorophyll fluorescence and gross primary production simulated by the two-leaf light use efficiency model was similar in spring, summer, and autumn. The proportion of spatial variations of sun-induced chlorophyll fluorescence and annual gross primary production simulated by the two-leaf light use efficiency model explained by ranged from 0.76 (2011) to 0.80 (2013) during the study period. Overall, the two-leaf light use efficiency model was capable of capturing spatial and temporal variations in gross primary production in China. However, the model needs further improvement to better simulate gross primary production in summer. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. The Seasonal Cycle of Satellite Chlorophyll Fluorescence Observations and its Relationship to Vegetation Phenology and Ecosystem Atmosphere Carbon Exchange

    Science.gov (United States)

    Joiner, J.; Yoshida, Y.; Vasilkov, A. P.; Schaefer, K.; Jung, M.; Guanter, L.; Zhang, Y; Garrity, S.; Middleton, E. M.; Huemmrich, K. F.; hide

    2014-01-01

    Mapping of terrestrial chlorophyll uorescence from space has shown potentialfor providing global measurements related to gross primary productivity(GPP). In particular, space-based fluorescence may provide information onthe length of the carbon uptake period that can be of use for global carboncycle modeling. Here, we examine the seasonal cycle of photosynthesis asestimated from satellite fluorescence retrievals at wavelengths surroundingthe 740nm emission feature. These retrievals are from the Global OzoneMonitoring Experiment 2 (GOME-2) flying on the MetOp A satellite. Wecompare the fluorescence seasonal cycle with that of GPP as estimated froma diverse set of North American tower gas exchange measurements. Because the GOME-2 has a large ground footprint (40 x 80km2) as compared with that of the flux towers and requires averaging to reduce random errors, we additionally compare with seasonal cycles of upscaled GPP in the satellite averaging area surrounding the tower locations estimated from the Max Planck Institute for Biogeochemistry (MPI-BGC) machine learning algorithm. We also examine the seasonality of absorbed photosynthetically-active radiation(APAR) derived with reflectances from the MODerate-resolution Imaging Spectroradiometer (MODIS). Finally, we examine seasonal cycles of GPP as produced from an ensemble of vegetation models. Several of the data-driven models rely on satellite reflectance-based vegetation parameters to derive estimates of APAR that are used to compute GPP. For forested sites(particularly deciduous broadleaf and mixed forests), the GOME-2 fluorescence captures the spring onset and autumn shutoff of photosynthesis as delineated by the tower-based GPP estimates. In contrast, the reflectance-based indicators and many of the models tend to overestimate the length of the photosynthetically-active period for these and other biomes as has been noted previously in the literature. Satellite fluorescence measurements therefore show potential for

  12. Quality evaluation of the edible blue-green alga Nostoc flagelliforme using a chlorophyll fluorescence parameter and several biochemical markers.

    Science.gov (United States)

    Gao, Xiang; Yang, Yiwen; Ai, Yufeng; Luo, Hongyi; Qiu, Baosheng

    2014-01-15

    Nostoc flagelliforme is an edible blue-green alga with herbal and dietary values. Due to the diminishing supply of natural N. flagelliforme and the large investment on the development of its cultivation technology, it is anticipated that artificially cultured N. flagelliforme will soon sustain the market supply. Once this change occurs, the storage-associated quality problem will become the focus of attention for future trade. In this paper, we used a chlorophyll fluorescence parameter, maximum quantum efficiency of Photosystem II (Fv/Fm), and several biomarkers to evaluate the quality of several N. flagelliforme samples. It was found that longer storage times resulted in darker coloured solutions (released pigments) and decreased amounts of chlorophyll a (Chl a) and water-soluble sugars (WSS). Additionally, a higher Fv/Fm value suggests better physiological recovery and quality. In actual application, determination of Fv/Fm would be the first step for evaluating the quality of N. flagelliforme, and the biochemical indexes would serve as good secondary markers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Effects of ozone impact on the gas exchange and chlorophyll fluorescence of juvenile birch stems (Betula pendula Roth.)

    Energy Technology Data Exchange (ETDEWEB)

    Wittmann, Christiane [Department of Applied Botany, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen (Germany); Matyssek, Rainer [Department of Ecology/Ecophysiology of Plants, Technische Universitaet Muenchen, 85354 Freising/Weihenstephan (Germany); Pfanz, Hardy [Department of Applied Botany, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen (Germany)], E-mail: hardy.pfanz@uni-due.de; Humar, Maja [Department of Agronomy, Biotechnical Faculty, University of Ljubljana (Slovenia)

    2007-11-15

    Effects of ozone impact on gas exchange and chlorophyll fluorescence of juvenile birch (Betula pendula) stems and leaves were investigated. Significant differences in the response of leaves and stems to ozone were found. In leaves, O{sub 3} exposure led to a significant decline in photosynthetic rates, whereas stems revealed an increased dark respiration and a concomitant increase in corticular photosynthesis. In contrast to birch leaves, corticular photosynthesis appeared to support the carbon balance of stems or even of the whole-tree under O{sub 3} stress. The differences in the ozone-response between leaves and stems were found to be related to ozone uptake rates, and thus to inherent differences in leaf and stem O{sub 3} conductance. - Leaves of birch were more affected by ozone fumigation than corresponding stems, due to a higher ozone uptake rate.

  14. High Spatio-Temporal-Resolution Detection of Chlorophyll Fluorescence Dynamics from a Single Chloroplast with Confocal Imaging Fluorometer

    CERN Document Server

    Tseng, Yi-Chin

    2016-01-01

    Chlorophyll fluorescence (CF) is a key indicator to study plant physiology or photosynthesis efficiency. Conventionally, CF is characterized by fluorometers, which only allows ensemble measurement through wide-field detection. For imaging fluorometers, the typical spatial and temporal resolutions are on the order of millimeter and second, far from enough to study cellular/sub-cellular CF dynamics. In addition, due to the lack of optical sectioning capability, conventional imaging fluorometers cannot identify CF from a single cell or even a single chloroplast. Here we demonstrated a novel fluorometer based on confocal imaging, that not only provides high contrast images, but also allows CF measurement with spatiotemporal resolution as high as micrometer and millisecond. CF transient (the Kautsky curve) from a single chloroplast is successfully obtained, with both the temporal dynamics and the intensity dependences corresponding well to the ensemble measurement from conventional studies. The significance of con...

  15. Non-invasive measurements of leaf epidermal transmittance of UV radiation using chlorophyll fluorescence: field and laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.W. [Southwest Texas State Univ.. Dept. of Biology, San Marcos, TX (United States); Searles, P.S.; Ryel, R.J.; Caldwell, M.M. [Utah State Univ., Dept. of Rangeland Resources and the Ecology Center, Logan, UT (United States); Ballare, C.L. [IFEVA, Univ. de Buenos Aires, Dept. de Ecologia, Facultad de Agronomia, Buenos Aires, (Argentina)

    2000-07-01

    Ratios of chlorophyll fluorescence induced by ultraviolet (UV) and bluegreen (BG) radiation [F(UV)/F(BG)] were determined with a Xe-PAM fluorometer to test the utility of this technique as a means of non-intrusively assessing changes in the pigmentation and optical properties of leaves exposed to varying UV exposures under laboratory and field conditions. For plants of Vicia faba and Brassica campestris, grown under controlled-environmental conditions, F(UV-B)/F(BG) was negatively correlated with whole-leaf UV-B-absorbing pigment concentrations. Fluorescence ratios of V.faba were similar to, and positively correlated with (r{sup 2} = 0.77 [UV-B]; 0.85 [UV-A]), direct measurements of epidermal transmittance made with an integrating sphere. Leaves of 2 of 4 cultivars of field-grown Glycine max exposed to near-ambient solar UV-B at a mid-latitude site (Buenos Aires, Argentina, 34 degrees S) showed significantly lower abaxial F(UV-B)/F(BG) values (i.e., lower UV-B epidermal transmittance) than those exposed to attenuated UV-B, but solar UV-B reduction had a minimal effect on F(UV-B)/F(BG) in plants growing at a high-latitude site (Tierra del Fuego, Argentina, 55 degrees S). Similarly, the exotic Taraxacum officinale did not show significant changes in F(UV-B)/F(BG) when exposed to very high supplemental UV-B (biologically effective UV-B = 14-15 kJ m{sup -2} day{sup -1}) in the field in Tierra del Fuego, whereas a native species, Gunnera magellanica, showed significant increases in F(UV-B)/F(BG) relative to those receiving ambient UV-B. These anomalous fluorescence changes were associated with increases in BG-absorbing pigments (anthocyanins), but not UV-B-absorbing pigments. These results indicate that non-invasive estimates of epidermal transmittance of UV radiation using chlorophyll fluorescence can detect changes in pigmentation and leaf optical properties induced by UV-B radiation under both field and laboratory conditions. However, this technique may be of limited

  16. On the polyphasic quenching kinetics of chlorophyll a fluorescence in algae after light pulses of variable length.

    Science.gov (United States)

    Vredenberg, Wim; Prasil, Ondrej

    2013-11-01

    This study reports on kinetics of the fluorescence decay in a suspension of the alga Scenedesmus quadricauda after actinic illumination. These are monitored as the variable fluorescence signal in the dark following light pulses of variable intensity and duration. The decay reflects the restoration of chlorophyll fluorescence quenching of the photosystem II (PSII) antennas and shows a polyphasic pattern which suggests the involvement of different processes. The overall quenching curve after a fluorescence-saturating pulse (SP) of 250-ms duration, commonly used in pulse amplitude modulation applications as the tool for estimating the maximal fluorescence (F m), has been termed P-O, in which P and O have the same meaning as used in the OJIP induction curve in the light. Deconvolution of this signal shows at least three distinguishable exponential phases with reciprocal rate constants of the order of 10, 10(2), and 10(3) ms. The size of the long (>10(3) ms) and moderate (~10(2) ms) lasting components relative to the complete quenching signal after an SP increases with the duration of the actinic pulse concomitantly with an increase in the reciprocal rate constants of the fast (~10 ms) and moderate quenching phases. Fluorescence responses upon single turnover flashes of 30-μs duration (STFs) given at discrete times during the P-O quenching were used as tools for identifying the quencher involved in the P-O quenching phase preceding the STF excitation. Results are difficult to interpret in terms of a single-hit two-state trapping mechanism with distinguishable quenching properties of open and closed reaction centers only. They give support for an earlier hypothesis on a double-hit three-state trapping mechanism in which the so-called semi-closed reaction centers of PSII are considered. In these trapping-competent centers the single reduced acceptor pair [PheQ A](1-), depending on the size of photoelectrochemically induced pH effects on the Q B-binding site

  17. Response of carbon assimilation and chlorophyll fluorescence to soybean leaf phosphorus across CO2: Alternative electron sink, nutrient efficiency and critical phosphorus concentration

    Science.gov (United States)

    To evaluate the response of CO2 assimilation (PN) and various chlorophyll fluorescence (CF) parameters to phosphorus (P) nutrition soybean plants were grown in controlled environment growth chambers with sufficient (0.50 mM) and deficient (0.10 and 0.01 mM) P supply under ambient and elevated CO2 (a...

  18. Theoretical reconsiderations when estimating the mesophyll conductance to CO2 diffusion in leaves of C3 plants by analysis of combined gas exchange and chlorophyll fluorescence measurements

    NARCIS (Netherlands)

    Yin, X.; Struik, P.C.

    2009-01-01

    Existing methods to estimate the mesophyll conductance to CO2 diffusion (gm) are often based on combined gas exchange and chlorophyll fluorescence measurements. However, estimations of average gm by these methods are often unreliable either because the range of usable data is too narrow or because

  19. Spatio-temporal patterns of chlorophyll fluorescence and physiological and structural indices acquired from hyperspectral imagery as compared with carbon fluxes measured with eddy covariance

    NARCIS (Netherlands)

    Zarco-Tejada, P.J.; Morales Sierra, A.; Testi, L.; Villalobos, F.

    2013-01-01

    This study provides insight into the assessment of the spatio-temporal trends of chlorophyll fluorescence, narrow-band physiological indices, and structural indices acquired with a hyperspectral imager flown over a flux tower in a canopy characterized by small seasonal structural changes and a

  20. Optical properties of the adaxial and abaxial faces of leaves. Chlorophyll fluorescence, absorption and scattering coefficients.

    Science.gov (United States)

    Cordón, Gabriela B; Lagorio, María G

    2007-08-01

    Emission fluorescence spectra were obtained for the adaxial and abaxial faces of dicotyledonous (Ficus benjamina L., Ficus elastica, Gardenia jasminoides and Hedera helix) and monocotyledonous leaves (Gladiolus spp. and Dracaena cincta bicolor). After correction by light-re-absorption processes, using a previously published physical model, the adaxial faces of dicotyledons showed a fluorescence ratio Fred/Ffar-red rather lower than the respective values for the abaxial faces. Monocotyledons and shade-adapted-plants showed similar values for the corrected fluorescence ratio for both faces. Even when differences in experimental fluorescence emission from adaxial and abaxial leaves in dicotyledons are mostly due to light re-absorption processes, the residual dissimilarity found after application of the correction model would point to the fact that fluorescence re-absorption is not the only responsible for the observed disparity. It was concluded that light re-absorption processes does not account entirely for the differences in the experimental emission spectra between adaxial and abaxial leaves. Differences that remains still present after correction might be interpreted in terms of a different photosystem ratio (PSII/PSI). Experiments at low temperature sustained this hypothesis. In dicotyledons, light reflectance for adaxial leaves was found to be lower than for the abaxial ones. It was mainly due to an increase in the scattering coefficient for the lower leaf-side. The absorption coefficient values were slightly higher for the upper leaf-side. During senescence of Ficus benjamina leaves, the scattering coefficient increased for both the upper and lower leaf-sides. With senescence time the absorption coefficient spectra broadened while the corrected fluorescence ratio (Fred/Ffar-red) decreased for both faces. The results pointed to a preferential destruction of photosystem II relative to photosystem I during senescence.

  1. Remotely Measured Terrestrial Chlorophyll Fluorescence Using Airborne G-LiHT and APFS Sensors

    Science.gov (United States)

    Cook, W. B.; Yee, J. H.; Corp, L. A.; Cook, B. D.; Huemmrich, K. F.

    2014-12-01

    In September 2014 the Goddard Lidar, Hyperspectral and Thermal (G-LiHT) and the APL/JHU Airborne Plant Fluorescence Sensor (APFS) were flown together on a NASA Langley King Air over vegetated targets in North Carolina and Virginia. The instruments provided high spatial and spectral resolution data in the visible and near infrared, down-welling irradiance, elevation maps, and thermal imagery. Ground validation data was also collected concurrently. Here we report the results of these measurements and show the feasibility of using these types of instruments for collection the fluorescence and other information essential for ecological and carbon cycle studies.

  2. Effects of ambient versus reduced UV-B radiation on high arctic Salix arctica assessed by measurements and calculations of chlorophyll-a fluorescence parameters from fluorescence transients

    DEFF Research Database (Denmark)

    Albert, Kristian Rost

    2005-01-01

    A UV-B exclusion-experiment was conducted in the high arctic Zackenberg, NE Greenland, in which Salix arctica leaves during most of the growing season were fixed perpendicular to the solar zenith angle, thereby receiving maximal solar radiation. Covered with Teflon and Mylar foil, the leaves...... of evaluating the relative importance of UV-B of donor and acceptor side capacity in Photosystem II. In conclusion, the experimental set-up and non-invasive measurements proved to be a sensitive method to screen for effects of UV-B stress....... received approximately 90 and 40% of the ambient UV-B irradiance, respectively. The effects were examined through recordings of chlorophyll a fluorescence transients, determination of biomass and analysis of total carbon and nitrogen content and amount of soluble flavonoids in the leaves. The processing...

  3. Steady-state chlorophyll fluorescence (Fs) as an indicator of leaf %photosynthesis and stomatal conductance under drought conditions

    Science.gov (United States)

    Flexas, J.

    The steady-state chlorophyll fluorescence (Fs) presented different diurnal variation patterns in irrigated and water-stressed plants, the latter showing a midday depression, which was more pronounced as more severe was the stress. Here we address the possible causes of such variations and discuss the applicability of Fs for stress assessment. In water stress experiments with several C3 plants, the ratio of Fs normalised to dark-adapted intrinsic fluorescence (Fo) was negatively and exponentially correlated with non-photochemical quenching (NPQ). The relationship was abolished by treatment with DTT, an inhibitor of xanthophyll de-epoxidation. These and other evidences suggest that increased non-radiative dissipation under drought was responsible for Fs variations. Interestingly, the ratio Fs/Fo fixed at a given high light intensity directly correlated with CO2 assimilation in air, with electron transport rate and with stomatal conductance. Therefore, the ratio Fs/Fo, which can be measured with a remote sensing system, provides a good method for the early detection of water stress.

  4. Mercury effects on Thalassiosira weissflogii: Applications of two-photon excitation chlorophyll fluorescence lifetime imaging and flow cytometry

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yun [Division of Life Science, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (Hong Kong); Zeng Yan; Qu, Jianan Y. [Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (Hong Kong); Wang Wenxiong, E-mail: wwang@ust.hk [Division of Life Science, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (Hong Kong)

    2012-04-15

    The toxic effects of inorganic mercury [Hg(II)] and methylmercury (MeHg) on the photosynthesis and population growth in a marine diatom Thalassiosira weissflogii were investigated using two methods: two-photon excitation fluorescence lifetime imaging (FLIM) and flow cytometry (FCM). For photosynthesis, Hg(II) exposure increased the average chlorophyll fluorescence lifetime, whereas such increment was not found under MeHg stress. This may be caused by the inhibitory effect of Hg(II) instead of MeHg on the electron transport chain. For population growth, modeled specific growth rate data showed that the reduction in population growth by Hg(II) mainly resulted from an increased number of injured cells, while the live cells divided at the normal rates. However, MeHg inhibitory effects on population growth were contributed by the reduced division rates of all cells. Furthermore, the cell images and the FCM data reflected the morphological changes of diatom cells under Hg(II)/MeHg exposure vividly and quantitatively. Our results demonstrated that the toxigenicity mechanisms between Hg(II) and MeHg were different in the algal cells.

  5. Multiple effects of chromate on the photosynthetic apparatus of Spirodela polyrhiza as probed by OJIP chlorophyll a fluorescence measurements.

    Science.gov (United States)

    Appenroth, K J; Stöckel, J; Srivastava, A; Strasser, R J

    2001-01-01

    Chromate (Cr) decreases the growth of Spirodela polyrhiza. The fronds lost their pigments. The O2 evolution was also decreased. The Cr effect was found to be dose dependent. The toxic effects of Cr have further been studied on the photosynthetic activity of Spirodela polyrhiza by means of the chlorophyll a (Chl a) fluorescence transient O-J-I-P. The Chl a fluorescence transients were recorded in vivo with high time resolution and analyzed according to the JIP-test which can quantify the photosystem II behavior. Cr treated plants show a decrease in yield for primary photochemistry, phi Po. The performance index of PSII, PIABS, which is the combination of the indexes of three independent parameters, (1) the total number of active reaction centers per absorption (RC/ABS), (2) yield of primary photochemistry (phi Po) and (3) efficiency with which a trapped exciton can move an electron into the electron transport chain (psi 0), decreased due to Cr treatment. Chromate sensitivity varies within plant populations. In summary Cr affects several targets of PSII. More specifically, the main targets of Cr, according to the JIP-test, can be listed as a decrease in the number of active reaction centers and damage to the oxygen-evolving complex.

  6. Vegetation stress from soil moisture and chlorophyll fluorescence: synergy between SMAP and FLEX approaches

    Science.gov (United States)

    Moreno, Jose; Moran, Susan

    2014-05-01

    Vegetation stress detection continues being a focal objective for remote sensing techniques. It has implications not only for practical applications such as irrigation optimization or precision agriculture, but also for global climate models, providing data to better link water and carbon exchanges between the surface and the atmospheric and improved parameterization of the role of terrestrial vegetation in the coupling of water and carbon cycles. Traditional approaches to map vegetation stress using remote sensing techniques have been based on measurements of soil moisture status, canopy (radiometric) temperature and, to a lesser extent, canopy water content, but new techniques such as the dynamics of vegetation fluorescence emission, are also now available. Within the context of the preparatory activities for the SMAP and FLEX missions, a number of initiatives have been put in place to combine modelling activities and field experiments in order to look for alternative and more efficient ways of detecting vegetation stress, with emphasis on synergistic remote sensing approaches. The potential of solar-induced vegetation fluorescence as an early indicator of stress has been widely demonstrated, for different type of stress conditions: light amount (excess illumination) and conditions (direct/diffuse), temperature extremes (low and high), soil water availability (soil moisture), soil nutrients (nitrogen), atmospheric water vapour and atmospheric CO2 concentration. The effects caused by different stress conditions are sometimes difficult to be decoupled, also because different causes are often combined, but in general they then to change the overall fluorescence emission (modulating amplitude) or changing the relative contributions of photosystems PSI and PSII or the relative fluorescence re-absorption effects caused by modifications in the structure of pigment bed responsible for light absorption, in particular for acclimation for persistent stress conditions. While

  7. Detection of the onset of glyphosate-induced soybean plant injury through chlorophyll fluorescence signal extraction and measurement

    Science.gov (United States)

    Zhao, Feng; Guo, Yiqing; Huang, Yanbo; Reddy, Krishna N.; Zhao, Yanhua; Molin, William T.

    2015-01-01

    In this study, chlorophyll fluorescence (ChlF) was used to detect the onset of soybean plant injury from treatment of glyphosate, the most widely used herbicide. Thirty-six pots of nonglyphosate-resistant soybean were randomly divided into three groups and treated with different doses of glyphosate solutions. The three treatment groups were control (CTRL) group (with no glyphosate treatment), 0.25X group (treated with 0.217 kg.ae/ha solution of glyphosate), and 0.5X group (treated with 0.433 kg.ae/ha solution of glyphosate). Three kinds of fluorescence measurements, steady-state fluorescence spectra, Kautsky effect parameters, and ChlF-related spectral indices were extracted and generated from the measurements in the glyphosate treatment experiment. The mean values of these fluorescence measurements for each of the CTRL group, the 0.25X group, and the 0.5X group were calculated. Glyphosate-induced leaf injury was then analyzed by examining the separability of these mean values at 6, 24, 48, and 72 hours after the treatment (HAT). Results indicate that the peak position of far-red ChlF shows an obvious blue shift for glyphosate-treated soybean, and peak values of steady-state fluorescence spectra for the three groups can be significantly distinguished from each other at 48 HAT and later. Four Kautsky effect parameters, Fv, Fv/Fm, Area, and PI, are parameters sensitive to glyphosate treatment, showing some differences between the CTRL group and treated groups at 24 HAT, and significant differences among the three groups at and beyond 48 HAT. Moreover, ChlF-related spectral indices, R6832/(R675.R690) and R690/R655, are also shown to be useful in detection of the glyphosate injury, though they are less effective than the steady-state fluorescence spectra and the Kautsky effect parameters. Based on the presented results, it can be concluded that glyphosate-induced soybean injury can be detected in a timely manner by the ChlF measurements, and this method has the

  8. Chlorophyll a fluorescence and herbicide efficacy, metabolism and selectivity

    DEFF Research Database (Denmark)

    Abbas Poor, Majid

    like black nightshade (Paper III). In field studies with logarithmic sprayer the effects of glyphosate (EPSPS inhibitor) and terbuthylazine (PSII inhibitor)mixed with three EC non-ionic adjuvants (Torpedo-II, Li-700 and Validate) on the fluorescence parameters were investigated in spring barley...... by analyzing the changes in Kautsky curve. Torpedo-II significantly increased the herbicide effect on fluorescence parameters while Li-700 decreased the effect. Spring barley sprayed with glyphosate died few weeks after spraying whether mixed with adjuvants or not while completely recovering from......) in the broad sense. This method can be used to test the effect of different adjuvants on efficacy of herbicides soon after spraying and be helpful in the quest for new and improved formulations and adjuvants....

  9. GAS EXCHANGE AND CHLOROPHYLL FLUORESCENCE OF CITRUS ROOTSTOCK VARIETIES UNDER SALT STRESS

    Directory of Open Access Journals (Sweden)

    MARCOS ERIC BARBOSA BRITO

    2016-01-01

    Full Text Available ABSTRACT High salt concentration in water are common in Brazilian semirad region, being important to research alternatives for use this waters on crop, like use of tolerant genotypes to salinity. Thus, in order to evaluate the saline stress perception of citrus rootstocks varieties crop from gas exchange and fluorescence analysis, an experiment was realized in greenhouse at the Center for Science and Technology Agrifood, CCTA, of Federal University of Campina Grande, UFCG, Pombal, PB, Brazil. It was studied in a randomized block design with factorial scheme (2x4, two salinity levels (0.3 and 4.0 dSm-1 and four varieties of citrus rootstocks [1 -common Sunki mandarin (TSKC, 2 - Florida Rough lemon (LRF, 3 -Santa Cruz Rangpur lime (LCRSTC and 4-Volkamer lemon (LVK], with three replications. The citrus rootstocks varieties grown on hydroponic system and at 90 days after sowing the plants were evaluated by gas exchange and PSII fluorescence at 0, 24 and 48 hours after application of treatments to determine the times for the physiological establishment of salt stress. The first 48h under saline conditions promoted changes in gas exchange and PSII fluorescence in varieties TSKC, LRF and LCRSTC indicating the begin of physiological stress; the common ‘Sunki’ mandarin and the ‘Florida Rough’ lemon are the more sensitive genotypes to saline stress, in order hand the ‘Santa Cruz Rangpur’ lime and ‘Volkamer’ lemon are the genotypes more tolerant.

  10. Effects of exogenous putrescine on gas-exchange characteristics and chlorophyll fluorescence of NaCl-stressed cucumber seedlings.

    Science.gov (United States)

    Zhang, Run Hua; Li, Jun; Guo, Shi Rong; Tezuka, Takafumi

    2009-06-01

    The effects of 10 mM putrescine (Put) treated by spraying on leaves on growth, chlorophyll content, photosynthetic gas-exchange characteristics, and chlorophyll fluorescence were investigated by growing cucumber plants (Cucumis sativus L. cv. ChangChun mici) using hydroponics with or without 65 mM NaCl as a salt stress. Salt stress caused the reduction of growth such as leaf area, root volume, plant height, and fresh and dry weights. Furthermore, net photosynthesis rate (P(n)), stomatal conductance (g(s)), intercellular CO(2) concentration (C(i)), and transpiration rate (T(r)) were also reduced by NaCl, but water use efficiency (WUE; P(n)/T(r)) showed a tendency to be enhanced rather than reduced by NaCl. However, Put alleviated the reduction of P (n) by NaCl, and showed a further reduction of C (i) by NaCl. The reduction of g(s) and T(r) by NaCl was not alleviated at all. The enhancement of WUE by NaCl was shown to have no alleviation at day 1 after starting the treatment, but after that, the enhancement was gradually reduced till the control level. Maximum quantum efficiency of PSII (F(v)/F(m)) showed no effects by any conditions based on the combination of NaCl and Put, and in addition, kept constant values in plants grown in each nutrient solution during this experimental period. The efficiency of excitation energy capture by open photosystem II (PSII) (F(v)'/F(m)'), actual efficiency of PSII (Phi(PSII)), and the coefficient on photochemical quenching (qP) of plants with NaCl were reduced with time, and the reduction was alleviated till the control level by treatment with Put. The F(v)'/F(m)', Phi(PSII), and qP of plants without NaCl and/or with Put showed no variation during the experiment. Non-photochemical quenching of the singlet excited state of chlorophyll a (NPQ) showed quite different manner from the others as mentioned above, namely, continued to enhance during the experiment.

  11. Detecting Crop Functional Response to a Heat Wave using Airborne Reflectance and Sun-induced Chlorophyll Fluorescence Measurements

    Science.gov (United States)

    Yang, P.; Van der Tol, C.; Rascher, U.; Damm, A.; Schickling, A.; Verhoef, W.

    2016-12-01

    This study presents an analysis of airborne measured reflectance (R) and solar-induced chlorophyll fluorescence (SIF) as indicators of high temperature stress in agricultural crops. We used atmospherically corrected R and retrievals of SIF in the O2-A band as obtained from HyPlant data over C3 crops (rapeseed, wheat and barley) and a C4 crop (corn) in Germany before (30th June) and during (2nd July) a heat wave in 2015. The availability of airborne data during this heat wave allowed us to detect fluorescence emission efficiency changes as an indicator of crop photosynthetic performance in response to temperature fluctuations. We found that SIF is affected relatively stronger by heat stress than R. This is according to expectation, because the R spectrum is determined by leaf properties and canopy structure, whereas top-of-canopy (TOC) SIF is also affected by the temperature dependent efficiencies of photochemical and non-photochemical quenching of fluorescence. With the model 'Soil Canopy Observation of Photosynthesis and Energy fluxes (SCOPE), we differentiated leaf optical parameters and canopy structure from the fluorescence quantum emission efficiency (FQE), i.e. the ratio of fluorescence production to light absorption of photosystems. The leaf optical and canopy structure parameters were retrieved from R by inversion of the radiative transfer module 'RTMo' of SCOPE. The retrieved parameters were further used to estimate the FQE from SIF measurements. It appeared that both the leaf water content CW and the FQE responded to the heat wave, but the responses were different for C3 and C4 crops. A slight reduction of CW occurred in C3 crops between the two days, but not in the C4 crop. The reduction of FQE was only significant in C3 crops, and ranged from 18% to 31% for various C3 species. These findings agree with the general knowledge that C4 plants are better adapted to high temperature than C3 plants, and comply with simulations from a biochemical model for C3

  12. Combining Sun-Induced Chlorophyll Fluorescence and Photochemical Reflectance Index Improves Diurnal Modeling of Gross Primary Productivity

    Directory of Open Access Journals (Sweden)

    Anke Schickling

    2016-07-01

    Full Text Available Sun-induced chlorophyll fluorescence (F is a novel remote sensing parameter providing an estimate of actual photosynthetic rates. A combination of this new observable and Monteith’s light use efficiency (LUE concept was suggested for an advanced modeling of gross primary productivity (GPP. In this demonstration study, we evaluate the potential of both F and the more commonly used photochemical reflectance index (PRI to approximate the LUE term in Monteith’s equation and eventually improve the forward modeling of GPP diurnals. Both F and the PRI were derived from ground and airborne based spectrometer measurements over two different crops. We demonstrate that approximating dynamic changes of LUE using F and PRI significantly improves the forward modeling of GPP diurnals. Especially in sugar beet, a changing photosynthetic efficiency during the day was traceable with F and incorporating F in the forward modeling significantly improved the estimation of GPP. Airborne data were projected to produce F and PRI maps for winter wheat and sugar beet fields over the course of one day. We detected a significant variability of both, F and the PRI within one field and particularly between fields. The variability of F and PRI was higher in sugar beet, which also showed a physiological down-regulation of leaf photosynthesis. Our results underline the potential of F to serve as a superior indicator for the actual efficiency of the photosynthetic machinery, which is linked to physiological responses of vegetation.

  13. Taxonomic and ecological relevance of the chlorophyll a fluorescence signature of tree species in mixed European forests.

    Science.gov (United States)

    Pollastrini, Martina; Holland, Vera; Brüggemann, Wolfgang; Bruelheide, Helge; Dănilă, Iulian; Jaroszewicz, Bogdan; Valladares, Fernando; Bussotti, Filippo

    2016-10-01

    The variability of chlorophyll a fluorescence (ChlF) parameters of forest tree species was investigated in 209 stands belonging to six European forests, from Mediterranean to boreal regions. The modifying role of environmental factors, forest structure and tree diversity (species richness and composition) on ChlF signature was analysed. At the European level, conifers showed higher potential performance than broadleaf species. Forests in central Europe performed better than those in Mediterranean and boreal regions. At the site level, homogeneous clusters of tree species were identified by means of a principal component analysis (PCA) of ChlF parameters. The discrimination of the clusters of species was influenced by their taxonomic position and ecological characteristics. The species richness influenced the tree ChlF properties in different ways depending on tree species and site. Tree species and site also affected the relationships between ChlF parameters and other plant functional traits (specific leaf area, leaf nitrogen content, light-saturated photosynthesis, wood density, leaf carbon isotope composition). The assessment of the photosynthetic properties of tree species, by means of ChlF parameters, in relation to their functional traits, is a relevant issue for studies in forest ecology. The connections of data from field surveys with remotely assessed parameters must be carefully explored. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  14. Physiological responses of Brassica napus to fulvic acid under water stress: Chlorophyll a fluorescence and antioxidant enzyme activity

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    Ramin Lotfi

    2015-10-01

    Full Text Available The ameliorative effect of fulvic acid (0, 300, and 600 mg L− 1 on photosystem II and antioxidant enzyme activity of the rapeseed (Brassica napus L. plant under water stress (60, 100, and 140 mm evaporation from class A pan was studied using split plots in a randomized complete block design with three replications. Results indicated that application of fulvic acid (FA improved the maximum quantum efficiency of PSII (Fv/Fm and performance index (PI of plants under both well-watered and limited-water conditions. The time span from Fo to Fm and the energy necessary for the closure of all reaction centers was significantly increased, but the size of the plastoquinone pool was reduced with increasing water stress levels. Plants treated with FA had higher peroxidase and catalase activities under all irrigation conditions. Activities of ascorbate peroxidase and superoxide dismutase in plants increased with increasing water stress. Malondialdehyde increased under severe water stress, but application of FA significantly decreased lipid peroxidation. Production of reactive oxygen species (ROS is a common phenomenon in plants under stress. Under this condition, the balance between the production of ROS and the quenching activity of antioxidants is upset, often resulting in oxidative damage. In this study, application of FA significantly increased fluorescence of chlorophyll a, inhibiting ROS production and enhancing antioxidant enzymes activity that destroyed ROS. Thus, ROS in plant cells was reduced under water stress by application of FA and consequently lipid peroxidation was reduced.

  15. Angular normalization of GOME-2 Sun-induced chlorophyll fluorescence observation as a better proxy of vegetation productivity

    Science.gov (United States)

    He, Liming; Chen, Jing M.; Liu, Jane; Mo, Gang; Joiner, Joanna

    2017-06-01

    Sun-induced chlorophyll fluorescence (SIF) has been regarded as a promising proxy for gross primary productivity (GPP) over land. Considerable uncertainties in GPP estimation using remotely sensed SIF exist due to variations in the Sun-satellite view observation geometry that could induce unwanted variations in SIF observation. In this study, we normalize the far-red Global Ozone Monitoring Experiment-2 SIF observations on sunny days to hot spot direction (SIFh) to represent sunlit leaves and compute a weighted sum of SIF (SIFt) from sunlit and shaded leaves to represent the canopy. We found that SIFh is better correlated with sunlit GPP simulated by a process-based ecosystem model and SIFt is better correlated with the simulated total GPP than the original SIF observations. The coefficient of determination (R2) are increased by 0.04 ± 0.03, and 0.07 ± 0.04 on a global average using SIFh and SIFt, respectively. The most significant increases of the R2 (0.09 ± 0.04 for SIFt and 0.05 ± 0.03 for SIFh) appear in deciduous broadleaf forests.

  16. Diurnal and Seasonal Responses of High Frequency Chlorophyll Fluorescence and PRI Measurements to Abiotic Stress in Almonds

    Science.gov (United States)

    Bambach-Ortiz, N. E.; Paw U, K. T.

    2016-12-01

    Plants have evolved to efficiently utilize light to synthesize energy-rich carbon compounds, and at the same time, dissipate absorbed but excessive photon that would otherwise transfer excitation energy to potentially toxic reactive oxygen species (ROS). Nevertheless, even the most rapidly growing plants with the highest rates of photosynthesis only utilize about half of the light their leaves absorb during the hours of peak irradiance in sun-exposed habitats. Usually, that daily peak of irradiance coincides with high temperature and a high vapor pressure deficit, which are conditions related to plant stomata closure. Consequently, specially in water stressed environments, plants need to have mechanisms to dissipate most of absorbed photons. Plants avoid photo-oxidative damage of the photosynthetic apparatus due to the formation of ROS under excess light using different mechanisms in order to either lower the amount of ROS formation or detoxify already formed ROS. Photoinhibition is defined as a reduction in photosynthetic activity due largely to a sustained reduction in the photochemical efficiency of Photosystem II (PSII), which can be assessed by monitoring Chlorophyll a fluorescence (ChlF). Alternatively, monitoring abiotic stress effects upon photosynthetic activity and photoinhibition may be possible using high frequency spectral reflectance sensors. We aim to find the potential relationships between high frequency PRI and ChlF as indicators of photoinhibition and permanent photodamage at a seasonal scale. Preliminary results show that PRI responses are sensitive to photoinhibition, but provide a poor representation of permanent photodamage observed at a seasonal scale.

  17. Evaluation of Chlorophyll Fluorescence and Biochemical Traits of Lettuce under Drought Stress and Super Absorbent or Bentonite Application

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    Akram Valizadeh Ghale Beig

    2014-03-01

    Full Text Available The effects of two superabsorbents (natural-bentonite and (synthetic-A 200 on the chlorophyll fluorescence index, proline accumulation, phenolic compounds, antioxidant activity and total carbohydrate in lettuce (Lactuca sativa L. was evaluated. For this purpose, a factorial experiment using completely randomized design with superabsorbents at 3 levels (0, 0.15, 0.30 w/w%, drought stress at 2 levels (60 and 100% of field capacity and 4 replicates was conducted. Results showed that photosystem photochemical efficiency (Fv/Fm II under drought stress (60% FC as well as lower levels of bentonite superabsorbent polymer reduced. The minimum and maximum proline content were obtained in 0.3% bentonite, 100% FC and 0 benetonite, 60% FC, respectively. The lowest and highest phenolic compounds was corresponded to the highest levels in both super absorbents and control respectively, so that the super absorbent and bentonite, reduced phenolic compounds by 62.65 and 66.21% compared to control. 0 and 0.15 wt % bentonite in high drought stress (60% FC showed the highest and 0.3 wt % bentonite and 100% FC attained the lowest level of antioxidant activity. Control bentonite treatment beds at 60% FC and beds containing 0.3 wt. % bentonite in 100% FC, showed the lowest and the highest total carbohydrate content respectively. Results of this study indicate that bentonite can reduce the negative effects of drought stress similar to artificial super absorbent.

  18. High-throughput growth prediction for Lactuca sativa L. seedlings using chlorophyll fluorescence in a plant factory with artificial lighting

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    Shogo eMoriyuki

    2016-03-01

    Full Text Available Poorly grown plants that result from differences in individuals lead to large profit losses for plant factories that use large electric power sources for cultivation. Thus, identifying and culling the low-grade seedlings at an early stage, using so-called seedling diagnosis technology, plays an important role in avoiding large losses in plant factories. In this study, we developed a high-throughput diagnosis system using the measurement of chlorophyll fluorescence (CF in a commercial large-scale plant factory, which produces about 5,000 lettuce plants every day. At an early stage (6 days after sowing, a CF image of 6,000 seedlings was captured every 4 hours on the final greening day by a high-sensitivity CCD camera and an automatic transferring machine, and biological indices were extracted. Using machine learning, plant growth can be predicted with a high degree of accuracy based on biological indices including leaf size, amount of CF, and circadian rhythms in CF. Growth prediction was improved by addition of temporal information on CF. The present data also provide new insights into the relationships between growth and temporal information regulated by the inherent biological clock.

  19. An explanation for the inter-species variability of the photoprotective non-photochemical chlorophyll fluorescence quenching in diatoms.

    Science.gov (United States)

    Lavaud, Johann; Lepetit, Bernard

    2013-03-01

    Diatoms are a major group of microalgae whose photosynthetic productivity supports a substantial part of the aquatic primary production. In their natural environment they have to cope with strong fluctuations of the light climate which can be harmful for photosynthesis. In order to prevent the damage of their photosynthetic machinery, diatoms use fast regulatory processes among which the non-photochemical quenching of chlorophyll a fluorescence (NPQ) is one of the most important. In a previous work, we highlighted differences in the kinetics and extent of NPQ between diatom species/strains originating from different aquatic habitats. We proposed that the NPQ differences observed between strains/species could potentially participate to their ecophysiological adaptation to the light environment of their respective natural habitat. In order to better understand the molecular bases of such differences, we compared the NPQ features of four strains/species of diatoms known for their NPQ discrepancy. We could identify new spectroscopic fingerprints concomitant to NPQ and the related xanthophyll cycle. These fingerprints helped us propose a molecular explanation for the NPQ differences observed between the diatom species/strains examined. The present work further strengthens the potential role of NPQ in the ecophysiology of diatoms. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Evaluation of Salt Stress Effect on Chlorophyll Fluorescence in Two Sugar beet (Beta vulgaris L. under Salicylate Foliar Application

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    M mohammady Cheraghabady

    2015-09-01

    Full Text Available To study of salicylic acid effect on chlorophyll fluorescence parameters under salt stress condition an experiment was conducted in Split factorial based on randomized complete block design with three replications at Shahid Chamran University of Ahwaz research farm. In 4-leaf stage after full expanded leaves, simultaneous with 150 mM NaCl salt stress applying; the leaves of salicylic acid including 0, 0.5 and 1 mM was sprayed on the leaves early morning. Two cultivars (Jolge and Sharif of sugar beet were used at this experiment. Growth analysis was done at vegetative stage and ripening. Salinity caused significant reduction in root and shoot dry weight, stomatal conductance, SPAD value,Ф PSІІ, qP and Fv/Fm. Also salt stress resulted in significant increase in NPQ. Treatment by salicylic acid caused significant increase of root dry weight, stomatal conductance conditions stress, SPAD value,Ф PSІІ, qP and Fv/Fm compared to not application of salicylic acid under salt stress conditions. According to the results of the Correlation, photochemical quenching excited electron energy (qP and root dry weight (r = 0.56* and shoot dry weight (r = 0.68** stress conditions showed a significant positive correlation. Therefore this attribute can be used to screen for these cultivars under the conditions foliar salicylic acid.

  1. Modern stromatolite phototrophic communities: a comparative study of procaryote and eucaryote phototrophs using variable chlorophyll fluorescence.

    Science.gov (United States)

    Perkins, Rupert G; Mouget, Jean-Luc; Kromkamp, Jacco C; Stolz, John; Pamela Reid, R

    2012-12-01

    Stromatolites are laminated organosedimentary structures formed by microbial communities, principally cyanobacteria although eucaryote phototrophs may also be involved in the construction of modern stromatolites. In this study, productivity and photophysiology of communities from stromatolites (laminated) and thrombolites (nonlaminated) were analysed using fluorescence imaging. Sub-samples of mats were excised at Highborne Cay, Bahamas, and cross-sectioned to simultaneously analyse surface, near-surface (1-2 mm), and deeper (2-10 mm) communities. Rapid light curve parameters and nonphotochemical downregulation showed distinct differences between phototroph communities, consistent with the reported quasi-succession of classic stromatolite mat types. Greater productivity was shown by cyanobacteria in Type 1 and Type 3 mats (first and final stage of the succession, Schizothrix gebeleinii and Solentia sp. respectively) and lower productivity within Type 2 mats (intermediate mat type). Eucaryote mat types, dominated by stalked (Striatella sp. and Licmophora sp.) and tube-dwelling (e.g. Nitzschia and Navicula spp.) diatoms, showed greater productivity than cyanobacteria communities, with the exception of Striatella (low productivity) and an unidentified coccoid cyanobacterium (high productivity). Findings indicate comparative variability between photosynthetically active procaryote and eucaryote sub-communities within stromatolites, with a pattern logically following the succession of 'classic' mat types, and lower than the productivity of eucaryote dominated 'nonclassic' mat types. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  2. Imaging of fast chlorophyll fluorescence induction curve (OJIP) parameters, applied in a screening study with wild barley (Hordeum spontaneum) genotypes under heat stress.

    Science.gov (United States)

    Jedmowski, Christoph; Brüggemann, Wolfgang

    2015-10-01

    We quantified the influence of heat stress (HS) on PSII by imaging of parameters of the fast chlorophyll fluorescence (CF) induction (OJIP) kinetic of 20 genotypes of wild barley (Hordeum spontaneum) covering a broad geographical spectrum. We developed a standardised screening procedure, allowing a repetitive fluorescence measurement of leaf segments. The impact of HS was quantified by calculating a Heat Resistance Index (HRI), derived from the decrease of the Performance Index (PI) caused by HS treatment and following recovery. For the genotype showing the lowest HRI, reduced maximum quantum yield (φP0) and increased relative variable fluorescence of the O-J phase (K-Peak) were detected after HS, whereas the basal fluorescence (F0) remained stable. An additional feature was a lowered fraction of active (QA-reducing) reaction centres (RCs). The disturbances disappeared after one day of recovery. Spatial heterogeneities of fluorescence parameters were detected, as the negative effect of HS was stronger in the leaf areas close to the leaf tip. The results of this study prove that chlorophyll fluorescence imaging (CFI) is suitable for the detection of HS symptoms and that imaging of JIP-Test parameters should be considered in future screening and phenotyping studies aiming for the characterisation of plant genotypes. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Cold-induced sudden reversible lowering of in vivo chlorophyll fluorescence after saturating light pulses : a sensitive marker for chilling susceptibility.

    Science.gov (United States)

    Larcher, W; Neuner, G

    1989-03-01

    In chilling-sensitive plants (Glycine max, Saintpaulia ionantha, Saccharum officinarum) a sudden reversible drop in chlorophyll fluorescence occurs during photosynthetic induction immediately following saturating light pulses at low temperatures in the range 4 to 8 degrees C. A comparison of two soybean cultivars of different chilling sensitivities revealed that this phenomenon, termed lowwave, indicates specific thresholds of low temperature stress. Its occurrence under controlled chilling can be regarded as a quantitative marker for screening chilling susceptibility in angiosperms.

  4. Comparative study of the water oxidizing reactions and the millisecond delayed chlorophyll fluorescence in photosystem II at different pH.

    Science.gov (United States)

    Gasanov, Ralphreed; Aliyeva, Samira; Arao, Sachiko; Ismailova, Aygun; Katsuta, Nobuhiro; Kitade, Hidetoshi; Yamada, Shuji; Kawamori, Asako; Mamedov, Fikret

    2007-02-01

    Water splitting activity, the multiline EPR signal associated with S(2)-state of the CaMn(4)-cluster and the fast and slow phases of the induction curve of the millisecond delayed chlorophyll fluorescence from photosystem II (PSII) in the pH range of 4.5-8.5 were studied in the thylakoid membranes and purified PSII particles. It has been found that O(2) evolution and the multiline EPR signal were inhibited at acidic (pK approximately 5.3) and alkaline (pK approximately 8.1) pH values, and were maximal at pH 6.0-7.0. Our results indicate that the loss of O(2) evolution and the S(2)-state multiline EPR signal associated with the decrease of the millisecond delayed chlorophyll fluorescence only in alkaline region (pH 7.0-8.5). Possible correlations of the millisecond delayed chlorophyll fluorescence components with the donor side reactions in PSII are discussed.

  5. Fluorescence LiDAR UFL-9 investigations of chlorophyll a, CDOM and TSM spatial distribution on the Lake Issyk-Kul

    Science.gov (United States)

    Pelevin, Vadim; Zavialov, Peter; Kremenetskiy, Vyacheslav; Osokina, Varya

    2016-04-01

    Results of two field surveys on the Lake Issyk-Kul made by Shirshov scientific group in 2014, 2015 are presented, obtained with the help of fluorescence LiDAR UFL-9. High resolution maps of spatial distribution of chlorophyll a, colored dissolved organic material (CDOM) and total suspended matter (TSM) concentrations in the upper water layer are shown and discussed. Issyk-Kul Lake is the ultra oligotrophic water body in which the concentrations of the conctituents mentioned above are fairly low, but well distinguishable by fluorescence lidar. Explorations were conducted onbord the moving medium-size research vessels in various weather and daytime conditions in continuous mode.

  6. SENSITIVITY TO ENVIRONMENTAL STRESS OF PRATA,JAPIRA AND VITÓRIA BANANA CULTIVARS PROVEN BY CHLOROPHYLL a FLUORESCENCE

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    PRISCILA NOBRES DOS SANTOS

    Full Text Available ABSTRACT This study aimed to evaluate the physiological responses to environmental stress during pre- and post-harvest of the following banana cultivars: Prata (AAB, Japira (AAAB and Vitoria (AAAB. Analyses were carried out on young plants at vegetative stage (daughter-plant and adult plants at reproductive stage (motherplant. The experimental design was completely randomized. In the in vivo pre-harvest analysis were used seven replications, in a factorial scheme (3x2x2, three cultivars and two stages (vegetative and reproductive and two collection periods (March and June. For the analysis of post-harvest quality were used five replications in a factorial design (3x2x5, corresponding to three cultivars, two development stages and five periods of post-harvest analysis, carried out every two days from stage 4 of fruit ripening. The chlorophyll a fluorescence emission kinetics showed low photochemical performance of the three cultivars in June, a period characterized by lower temperatures and water deficit. Prata was the cultivar with the lowest tolerance to abiotic physiological behavior changes, which also reflected in fruit quality, because there was a change in physical and physicochemical parameters. Japira and Vitoria cultivars showed similar physiological responses in the pre- and post-harvest periods, according to their phylogenetic proximity. The total performance index, i.e., the conservation of energy absorbed by PSII up to the reduction of the final PSI acceptors (PItotal and the di-malonic aldehyde (MDA content were significantly higher in Japira and Vitoria cultivars compared to Prata cultivar in the reproductive phase. There was no significant change in the potential quantum efficiency of PSII (FV / FM = jP0 among the three cultivars. It was concluded that Japira and Vitoria cultivars showed greater plasticity to tolerate or even adapt to abiotic variations keeping higher fruit yield. PItotal is the most sensitive parameter during

  7. Dynamics of leaf gas exchange, chlorophyll fluorescence and stem diameter changes during freezing and thawing of Scots pine seedlings.

    Science.gov (United States)

    Lindfors, Lauri; Hölttä, Teemu; Lintunen, Anna; Porcar-Castell, Albert; Nikinmaa, Eero; Juurola, Eija

    2015-12-01

    Boreal trees experience repeated freeze-thaw cycles annually. While freezing has been extensively studied in trees, the dynamic responses occurring during the freezing and thawing remain poorly understood. At freezing and thawing, rapid changes take place in the water relations of living cells in needles and in stem. While freezing is mostly limited to extracellular spaces, living cells dehydrate, shrink and their osmotic concentration increases. We studied how the freezing-thawing dynamics reflected on leaf gas exchange, chlorophyll fluorescence and xylem and living bark diameter changes of Scots pine (Pinus sylvestris L.) saplings in controlled experiments. Photosynthetic rate quickly declined following ice nucleation and extracellular freezing in xylem and needles, almost parallel to a rapid shrinking of xylem diameter, while that of living bark followed with a slightly longer delay. While xylem and living bark diameters responded well to decreasing temperature and water potential of ice, the relationship was less consistent in the case of increasing temperature. Xylem showed strong temporal swelling at thawing suggesting water movement from bark. After thawing xylem diameter recovered to a pre-freezing level but living bark remained shrunk. We found that freezing affected photosynthesis at multiple levels. The distinct dynamics of photosynthetic rate and stomatal conductance reveals that the decreased photosynthetic rate reflects impaired dark reactions rather than stomatal closure. Freezing also inhibited the capacity of the light reactions to dissipate excess energy as heat, via non-photochemical quenching, whereas photochemical quenching of excitation energy decreased gradually with temperature in agreement with the gas exchange data. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Modeling the Footprint and Equivalent Radiance Transfer Path Length for Tower-Based Hemispherical Observations of Chlorophyll Fluorescence

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    Xinjie Liu

    2017-05-01

    Full Text Available The measurement of solar-induced chlorophyll fluorescence (SIF is a new tool for estimating gross primary production (GPP. Continuous tower-based spectral observations together with flux measurements are an efficient way of linking the SIF to the GPP. Compared to conical observations, hemispherical observations made with cosine-corrected foreoptic have a much larger field of view and can better match the footprint of the tower-based flux measurements. However, estimating the equivalent radiation transfer path length (ERTPL for hemispherical observations is more complex than for conical observations and this is a key problem that needs to be addressed before accurate retrieval of SIF can be made. In this paper, we first modeled the footprint of hemispherical spectral measurements and found that, under convective conditions with light winds, 90% of the total radiation came from an FOV of width 72°, which in turn covered 75.68% of the source area of the flux measurements. In contrast, conical spectral observations covered only 1.93% of the flux footprint. Secondly, using theoretical considerations, we modeled the ERTPL of the hemispherical spectral observations made with cosine-corrected foreoptic and found that the ERTPL was approximately equal to twice the sensor height above the canopy. Finally, the modeled ERTPL was evaluated using a simulated dataset. The ERTPL calculated using the simulated data was about 1.89 times the sensor’s height above the target surface, which was quite close to the results for the modeled ERTPL. Furthermore, the SIF retrieved from atmospherically corrected spectra using the modeled ERTPL fitted well with the reference values, giving a relative root mean square error of 18.22%. These results show that the modeled ERTPL was reasonable and that this method is applicable to tower-based hemispherical observations of SIF.

  9. Responses of Photosynthesis, Chlorophyll Fluorescence and ROS-Scavenging Systems to Salt Stress During Seedling and Reproductive Stages in Rice

    Science.gov (United States)

    Moradi, Foad; Ismail, Abdelbagi M.

    2007-01-01

    Background and Aims Salinity is a widespread soil problem limiting productivity of cereal crops worldwide. Rice is particularly sensitive to salt stress during the seedling stage, with consequent poor crop establishment, as well as during reproduction where salinity can severely disrupt grain formation and yield. Tolerance at the seedling stage is weakly associated with tolerance during reproduction. Physiological responses to salinity were evaluated for contrasting genotypes, during the seedling and reproductive stages. Methods Three rice genotypes differing in their tolerance of salinity were evaluated in a set of greenhouse experiments under salt stress during both seedling stage and reproduction. Key Results Photosynthetic CO2 fixation, stomatal conductance (gs) and transpiration decreased substantially because of salt stress, but with greater reduction in the sensitive cultivar IR29. The tolerant lines IR651 and IR632 had more responsive stomata that tended to close faster during the first few hours of stress, followed by partial recovery after a brief period of acclimation. However, in the sensitive line, gs continued to decrease for longer duration and with no recovery afterward. Chlorophyll fluorescence measurements revealed that non-photochemical quenching increased, whereas the electron transport rate decreased under salt stress. Salt-tolerant cultivars exhibited much lower lipid peroxidation, maintained elevated levels of reduced ascorbic acid and showed increased activities of the enzymes involved in the reactive oxygen scavenging system during both developmental stages. Conclusions Upregulation of the anti-oxidant system appears to play a role in salt tolerance of rice, with tolerant genotypes also maintaining relatively higher photosynthetic function; during both the vegetative and reproductive stages. PMID:17428832

  10. In situ chlorophyll fluorescence kinetics as a tool to quantify effects on photosynthesis in Euphorbia cyparissias by a parasitic infection of the rust fungus Uromyces pisi.

    Science.gov (United States)

    Zhori, Alba; Meco, Marjol; Brandl, Helmut; Bachofen, Reinhard

    2015-11-21

    Photosynthesis is the key process for plant growth and development. The determination of chlorophyll fluorescence kinetics allows the quantification of effects on photosynthetic processes triggered by environmental stress factors such as, e.g., the infection by fungal phytopathogens. The technique is non-invasive, rapid and well suited for experimental field work. Healthy and Uromyces-infected plants of Euphorbia cyparissias were monitored directly in situ in the field using rapid fluorescence kinetics. Non-infected healthy plants show a typical maximum value for the relative variable fluorescence Fv/Fm of around 0.8 with occasional variation between the leaves from the plant top towards the base, while infected plants exhibited a strong gradient to low values at the base. The photosynthetic performance index (PI) showed a higher heterogeneity within the leaves in both plant types. The non-invasive and rapid measurement of chlorophyll fluorescence induction allows characterizing the photosynthetic capacity of healthy and infected plants and of parts of them directly in the field. The PI, is highly sensitive not only concerning infection, but also towards other local environmental influences.

  11. Characterization of diatom-derived lipids and chlorophyll within Holocene laminites, Saanich Inlet, British Columbia, using conventional and laser scanning fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stasiuk, L.D. [Natural Resources Canada, Geological Survey of Canada, Calgary, AB (Canada); Sanei, H. [University of Victoria, BC (Canada). School of Earth and Ocean Sciences

    2001-07-01

    Conventional fluorescence microscopy and visible light region fluorescence microspectrometry have been combined with laser scanning fluorescence microscopy (LSFM) to examine and characterize soluble sedimentary organic matter (SOM) in Holocene diatomaceous laminites from ODP core 1034, Saanich Inlet, British Columbia, Canada. Microscopic SOM in the laminites is dominated by two components: red-fluorescing chlorophyllinite, and yellow-fluorescing, diatom-derived oils. Both are commonly preserved within the interior of siliceous diatom auxospores and appear as an abundant and intense stain on mineral matter throughout the laminites. The mineral stain is classified as matrix chlorophyllinite and matrix oil, respectively. Accessory insoluble SOM consists of dinoflagellate, prasinophyte and coccoidal alginites, and rare woody huminite, funginite, and sporinite. Visible light region fluorescence microspectrometry of chlorophyllinite reveals a predominance at {lambda} max 670-675 nm, which is consistent with a chlorophyll a source based on comparison with reference samples of chlorophyll a and b. The consistency in {lambda}max and spectral character of chlorophyllinite with increasing depth in Saanich Inlet correlates with a high degree of chlorophyll preservation. Its distribution in the laminites is readily imaged by LSFM using either UV (363 nm) or blue (488 nm) laser excitation and >665 nm emission. Yellow-fluorescing diatom oils have {lambda}max ranging from 485 to 520 nm, suggesting that they may comprise up to 70 per cent saturates. The distribution of entrapped yellow-fluorescing diatom oils as well as matrix oils is also readily imaged with LSFM using a combination of UV laser excitation (363 nm) and 510{+-}40 nm emission. Laminae on the Saanich Inlet samples which are highly enriched in both diatom oils and 'reproductive' auxospore cells are interpreted as recording intense episodic spring diatom blooms. The observations reported here document

  12. UPSCALING OF SOLAR INDUCED CHLOROPHYLL FLUORESCENCE FROM LEAF TO CANOPY USING THE DART MODEL AND A REALISTIC 3D FOREST SCENE

    Directory of Open Access Journals (Sweden)

    W. Liu

    2017-10-01

    Full Text Available Solar induced chlorophyll a fluorescence (SIF has been shown to be an excellent proxy of photosynthesis at multiple scales. However, the mechanical linkages between fluorescence and photosynthesis at the leaf level cannot be directly applied at canopy or field scales, as the larger scale SIF emission depends on canopy structure. This is especially true for the forest canopies characterized by high horizontal and vertical heterogeneity. While most of the current studies on SIF radiative transfer in plant canopies are based on the assumption of a homogeneous canopy, recently codes have been developed capable of simulation of fluorescence signal in explicit 3-D forest canopies. Here we present a canopy SIF upscaling method consisting of the integration of the 3-D radiative transfer model DART and a 3-D object model BLENDER. Our aim was to better understand the effect of boreal forest canopy structure on SIF for a spatially explicit forest canopy.

  13. Upscaling of Solar Induced Chlorophyll Fluorescence from Leaf to Canopy Using the Dart Model and a Realistic 3d Forest Scene

    Science.gov (United States)

    Liu, W.; Atherton, J.; Mõttus, M.; MacArthur, A.; Teemu, H.; Maseyk, K.; Robinson, I.; Honkavaara, E.; Porcar-Castell, A.

    2017-10-01

    Solar induced chlorophyll a fluorescence (SIF) has been shown to be an excellent proxy of photosynthesis at multiple scales. However, the mechanical linkages between fluorescence and photosynthesis at the leaf level cannot be directly applied at canopy or field scales, as the larger scale SIF emission depends on canopy structure. This is especially true for the forest canopies characterized by high horizontal and vertical heterogeneity. While most of the current studies on SIF radiative transfer in plant canopies are based on the assumption of a homogeneous canopy, recently codes have been developed capable of simulation of fluorescence signal in explicit 3-D forest canopies. Here we present a canopy SIF upscaling method consisting of the integration of the 3-D radiative transfer model DART and a 3-D object model BLENDER. Our aim was to better understand the effect of boreal forest canopy structure on SIF for a spatially explicit forest canopy.

  14. Chlorophyll fluorescence imaging of photosynthetic activity and pigment contents of the resurrection plants Ramonda serbica and Ramonda nathaliae during dehydration and rehydration.

    Science.gov (United States)

    Gashi, Bekim; Babani, Fatbardha; Kongjika, Efigjeni

    2013-07-01

    The desiccation-tolerant plants of the R. serbica and R. nathaliae are resurrection plants which are able to fully recover their physiological function after anabiosis. A comparison of chlorophyll fluorescence imaging and photosynthetic pigment contents responses of R. serbica and, for the first time, R. nathaliae to dehydration and rehydration were investigated. For this purpose, plants after collection from their natural habitats were kept fully watered for 14 days at natural condition. The experiment was conducted with mature leaves of both species. R. serbica and R. nathaliae plants were dehydrated to 5.88 % and 7.87 % relative water content (RWC) by withholding water for 15 days, afterwards the plants were rehydrated for 72 hours to 94.67 % and 97.02 % RWC. During desiccation, R. serbica plants preserved the chlorophyll content about 84 %, while R. nathaliae about 90 %. During dehydration when RWC were more than 40 %, photochemical efficiency of PSII for photochemistry, the Fv/Fm ratio, decreased about 40 % in R. nathaliae plants, but a strong reduction with 60 % was recorded for R. serbica. Following rehydration, the Fv/Fm ratio recovered more rapidly in R. nathaliae. The higher photosynthetic rates could also be detected via imaging the chlorophyll fluorescence decrease ratio Rfd, which possessed higher values after rehydration leaves of R. nathaliae as compared to R. serbica. The results showed that the photosynthetic activity and chlorophyll contents after rehydration are recovered more rapidly in R. nathaliae in comparison to R. serbica.

  15. Estimation of vegetation photosynthetic capacity from space-based measurements of chlorophyll fluorescence for terrestrial biosphere models.

    Science.gov (United States)

    Zhang, Yongguang; Guanter, Luis; Berry, Joseph A; Joiner, Joanna; van der Tol, Christiaan; Huete, Alfredo; Gitelson, Anatoly; Voigt, Maximilian; Köhler, Philipp

    2014-12-01

    Photosynthesis simulations by terrestrial biosphere models are usually based on the Farquhar's model, in which the maximum rate of carboxylation (Vcmax ) is a key control parameter of photosynthetic capacity. Even though Vcmax is known to vary substantially in space and time in response to environmental controls, it is typically parameterized in models with tabulated values associated to plant functional types. Remote sensing can be used to produce a spatially continuous and temporally resolved view on photosynthetic efficiency, but traditional vegetation observations based on spectral reflectance lack a direct link to plant photochemical processes. Alternatively, recent space-borne measurements of sun-induced chlorophyll fluorescence (SIF) can offer an observational constraint on photosynthesis simulations. Here, we show that top-of-canopy SIF measurements from space are sensitive to Vcmax at the ecosystem level, and present an approach to invert Vcmax from SIF data. We use the Soil-Canopy Observation of Photosynthesis and Energy (SCOPE) balance model to derive empirical relationships between seasonal Vcmax and SIF which are used to solve the inverse problem. We evaluate our Vcmax estimation method at six agricultural flux tower sites in the midwestern US using spaced-based SIF retrievals. Our Vcmax estimates agree well with literature values for corn and soybean plants (average values of 37 and 101 μmol m(-2)  s(-1) , respectively) and show plausible seasonal patterns. The effect of the updated seasonally varying Vcmax parameterization on simulated gross primary productivity (GPP) is tested by comparing to simulations with fixed Vcmax values. Validation against flux tower observations demonstrate that simulations of GPP and light use efficiency improve significantly when our time-resolved Vcmax estimates from SIF are used, with R(2) for GPP comparisons increasing from 0.85 to 0.93, and for light use efficiency from 0.44 to 0.83. Our results support the use of

  16. Toxic Effects of Ethyl Cinnamate on the Photosynthesis and Physiological Characteristics of Chlorella vulgaris Based on Chlorophyll Fluorescence and Flow Cytometry Analysis

    Science.gov (United States)

    Jiao, Yang; Ouyang, Hui-Ling; Jiang, Yu-Jiao; Kong, Xiang-Zhen; He, Wei; Liu, Wen-Xiu; Yang, Bin; Xu, Fu-Liu

    2015-01-01

    The toxic effects of ethyl cinnamate on the photosynthetic and physiological characteristics of Chlorella vulgaris were studied based on chlorophyll fluorescence and flow cytometry analysis. Parameters, including biomass, F v/F m (maximal photochemical efficiency of PSII), ФPSII (actual photochemical efficiency of PSII in the light), FDA, and PI staining fluorescence, were measured. The results showed the following: (1) The inhibition on biomass increased as the exposure concentration increased. 1 mg/L ethyl cinnamate was sufficient to reduce the total biomass of C. vulgaris. The 48-h and 72-h EC50 values were 2.07 mg/L (1.94–2.20) and 1.89 mg/L (1.82–1.97). (2) After 24 h of exposure to 2–4 mg/L ethyl cinnamate, the photosynthesis of C. vulgaris almost ceased, manifesting in ФPSII being close to zero. After 72 h of exposure to 4 mg/L ethyl cinnamate, the F v/F m of C. vulgaris dropped to zero. (3) Ethyl cinnamate also affected the cellular physiology of C. vulgaris, but these effects resulted in the inhibition of cell yield rather than cell death. Exposure to ethyl cinnamate resulted in decreased esterase activities in C. vulgaris, increased average cell size, and altered intensities of chlorophyll a fluorescence. Overall, esterase activity was the most sensitive variable. PMID:26101784

  17. Toxic Effects of Ethyl Cinnamate on the Photosynthesis and Physiological Characteristics of Chlorella vulgaris Based on Chlorophyll Fluorescence and Flow Cytometry Analysis

    Directory of Open Access Journals (Sweden)

    Yang Jiao

    2015-01-01

    Full Text Available The toxic effects of ethyl cinnamate on the photosynthetic and physiological characteristics of Chlorella vulgaris were studied based on chlorophyll fluorescence and flow cytometry analysis. Parameters, including biomass, Fv/Fm (maximal photochemical efficiency of PSII, ФPSII (actual photochemical efficiency of PSII in the light, FDA, and PI staining fluorescence, were measured. The results showed the following: (1 The inhibition on biomass increased as the exposure concentration increased. 1 mg/L ethyl cinnamate was sufficient to reduce the total biomass of C. vulgaris. The 48-h and 72-h EC50 values were 2.07 mg/L (1.94–2.20 and 1.89 mg/L (1.82–1.97. (2 After 24 h of exposure to 2–4 mg/L ethyl cinnamate, the photosynthesis of C. vulgaris almost ceased, manifesting in ФPSII being close to zero. After 72 h of exposure to 4 mg/L ethyl cinnamate, the Fv/Fm of C. vulgaris dropped to zero. (3 Ethyl cinnamate also affected the cellular physiology of C. vulgaris, but these effects resulted in the inhibition of cell yield rather than cell death. Exposure to ethyl cinnamate resulted in decreased esterase activities in C. vulgaris, increased average cell size, and altered intensities of chlorophyll a fluorescence. Overall, esterase activity was the most sensitive variable.

  18. Diurnal Variability in Chlorophyll-a, Carotenoids, CDOM and SO42− Intensity of Offshore Seawater Detected by an Underwater Fluorescence-Raman Spectral System

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    Jing Chen

    2016-07-01

    Full Text Available A newly developed integrated fluorescence-Raman spectral system (λex = 532 nm for detecting Chlorophyll-a (chl-a, Chromophoric Dissolved Organic Matter (CDOM, carotenoids and SO42− in situ was used to successfully investigate the diurnal variability of all above. Simultaneously using the integration of fluorescence spectroscopy and Raman spectroscopy techniques provided comprehensive marine information due to the complementarity between the different excitation mechanisms and different selection rules. The investigation took place in offshore seawater of the Yellow Sea (36°05′40′′ N, 120°31′32′′ E in October 2014. To detect chl-a, CDOM, carotenoids and SO42−, the fluorescence-Raman spectral system was deployed. It was found that troughs of chl-a and CDOM fluorescence signal intensity were observed during high tides, while the signal intensity showed high values with larger fluctuations during ebb-tide. Chl-a and carotenoids were influenced by solar radiation within a day cycle by different detection techniques, as well as displaying similar and synchronous tendency. CDOM fluorescence cause interference to the measurement of SO42−. To avoid such interference, the backup Raman spectroscopy system with λex = 785 nm was employed to detect SO42− concentration on the following day. The results demonstrated that the fluorescence-Raman spectral system has great potential in detection of chl-a, carotenoids, CDOM and SO42− in the ocean.

  19. Deep two-photon microscopic imaging through brain tissue using the second singlet state from fluorescent agent chlorophyll α in spinach leaf.

    Science.gov (United States)

    Shi, Lingyan; Rodríguez-Contreras, Adrián; Budansky, Yury; Pu, Yang; Nguyen, Thien An; Alfano, Robert R

    2014-06-01

    Two-photon (2P) excitation of the second singlet (S₂) state was studied to achieve deep optical microscopic imaging in brain tissue when both the excitation (800 nm) and emission (685 nm) wavelengths lie in the "tissue optical window" (650 to 950 nm). S₂ state technique was used to investigate chlorophyll α (Chl α) fluorescence inside a spinach leaf under a thick layer of freshly sliced rat brain tissue in combination with 2P microscopic imaging. Strong emission at the peak wavelength of 685 nm under the 2P S₂ state of Chl α enabled the imaging depth up to 450 μm through rat brain tissue.

  20. Deep two-photon microscopic imaging through brain tissue using the second singlet state from fluorescent agent chlorophyll α in spinach leaf

    Science.gov (United States)

    Shi, Lingyan; Rodríguez-Contreras, Adrián; Budansky, Yury; Pu, Yang; An Nguyen, Thien; Alfano, Robert R.

    2014-06-01

    Two-photon (2P) excitation of the second singlet (S) state was studied to achieve deep optical microscopic imaging in brain tissue when both the excitation (800 nm) and emission (685 nm) wavelengths lie in the "tissue optical window" (650 to 950 nm). S2 state technique was used to investigate chlorophyll α (Chl α) fluorescence inside a spinach leaf under a thick layer of freshly sliced rat brain tissue in combination with 2P microscopic imaging. Strong emission at the peak wavelength of 685 nm under the 2P S state of Chl α enabled the imaging depth up to 450 μm through rat brain tissue.

  1. Diurnal variations in gas exchange and chlorophyll fluorescence in rice leaves: the cause for midday depression in CO2 photosynthetic rate

    Directory of Open Access Journals (Sweden)

    Debabrata Panda

    2011-12-01

    Full Text Available Gas exchange and chlorophyll fluorescence analysis were carried out to investigate the diurnal variations in photosynthesis in leaves of rice (Oryza sativa L.. Leaf CO2 photosynthetic rate (Pn showed a bimodal diurnal pattern and midday depression in Pn was observed at 13:00 h. Depression in Pn at midday was mostly attributed to stomatal limitation since the reduction in Pn was followed by the significant reduction in stomatal conductance (Gs. Midday depression in Pn was found to be associated with reversible inactivation of Photo-system II (PS II reaction centers and increase of photo-inhibition in response to high intensity as evidenced by the maximum efficiency of PS II (Fv/Fm decreased with increase of light intensity from 6:00 h to 16:00 h of a day. The minimal fluorescence (Fo gradually increased with increasing light intensity and reached its highest value at 13:00 h and on contrary the maximal fluorescence (Fm decreased and reached its lowest value at 13:00 h. Quantification of several chlorophyll fluorescence parameters (JIP-test like area above the fluorescence curve between Fo and Fm, phenomenological energy fluxes like electron transport per cross section (ETo/CS, active PS II reaction center per exited cross-section (RC/CSo and performance index (Pi were low in early morning, increasing with time and reaching a maximum at 9:00 h subsequently decreasing and reaching a minimum value at 13.00 h. On contrary the dissipation per cross-section (Dio/CS gradually increased with increasing light intensity and reached its highest value at 13:00 h. It is likely that PS II down-regulation and heat dissipation co-operated together to prevent the chloroplast from photo damage.

  2. Chlorophyll fluorescence as a predictive method for detection of browning disorders in 'Conference' pears and 'Jonagold' apples during controlled atmosphere storage

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    Saquet Adriano Arriel

    2002-01-01

    Full Text Available The chlorophyll fluorescence technique was evaluated as a possible predictive and nondestructive method to detect low-O2 and/or high-CO2 injuries in 'Conference' pears and 'Jonagold' apples stored in controlled atmosphere (CA. The fruits were kept at 0°C in air, 1% CO2 + 2% O2 or 3% CO2 + 1% O2 during five months. Fluorescence parameters of minimal fluorescence (Fo, maximal fluorescence (Fm, and potential quantum yield - (Fm-Fo:Fm, also denoted as Fv:Fm- as well as the incidence of browning disorders were evaluated at several times during storage. No incidence of browning disorders was observed in 'Jonagold' apples, however, they showed a decrease in Fv:Fm during storage time with no differences between the CA-conditions. Air-stored apples showed a higher decrease in Fv:Fm. On the other hand, 'Conference' pears kept in 3% CO2 + 1% O2 developed a lot of browning injuries such as core flush, flesh browning and cavities. Under this CA-condition, a pronounced decrease in the quotient Fv:Fm was observed already in the first 15 days of storage prior to the development of browning, and this behaviour remained during the whole storage period. The air-stored pears showed a similar behaviour as of the air-stored apples with a pronounced decrease in the Fv:Fm at the end of the storage period. The present results indicate that chlorophyll fluorescence is a promising technique to detect browning injuries in 'Conference' pears prior to their development.

  3. Chlorophyll a fluorescence as a tool in evaluating the effects of ABA content and ethylene inhibitors on quality of flowering potted Bougainvillea.

    Science.gov (United States)

    Ferrante, Antonio; Trivellini, Alice; Borghesi, Eva; Vernieri, Paolo

    2012-01-01

    Flowering potted plants during the postproduction stage are usually stored in inadequate environmental conditions. We evaluated the effect of the most common storage conditions and treatments on two Bougainvillea cultivars after harvest and during recovery. Flowering potted Bougainvillea plants were treated with 100 mL 2 mM amino-oxyacetic acid (AOA) or 500 ppb 1-methylcyclopropene (1-MCP) prior storage in dark at 14°C for simulating transport or storage conditions and, subsequently, transferred to growth chambers at 20°C in the light for one week for evaluating the recovery ability. The plant stress during the experiments was assessed by ethylene, ABA, and chlorophyll a fluorescence measurements. Ethylene production was affected by temperature rather than treatments. ABA concentration declined in leaves and flowers during storage and was not affected by treatments. Fluorescence parameters appear to be very useful for screening Bougainvillea cultivars resistant to prolonged storage periods.

  4. Chlorophyll a Fluorescence as a Tool in Evaluating the Effects of ABA Content and Ethylene Inhibitors on Quality of Flowering Potted Bougainvillea

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    Antonio Ferrante

    2012-01-01

    Full Text Available Flowering potted plants during the postproduction stage are usually stored in inadequate environmental conditions. We evaluated the effect of the most common storage conditions and treatments on two Bougainvillea cultivars after harvest and during recovery. Flowering potted Bougainvillea plants were treated with 100 mL 2 mM amino-oxyacetic acid (AOA or 500 ppb 1-methylcyclopropene (1-MCP prior storage in dark at 14∘C for simulating transport or storage conditions and, subsequently, transferred to growth chambers at 20∘C in the light for one week for evaluating the recovery ability. The plant stress during the experiments was assessed by ethylene, ABA, and chlorophyll a fluorescence measurements. Ethylene production was affected by temperature rather than treatments. ABA concentration declined in leaves and flowers during storage and was not affected by treatments. Fluorescence parameters appear to be very useful for screening Bougainvillea cultivars resistant to prolonged storage periods.

  5. Functional heterogeneity of the fucoxanthins and fucoxanthin-chlorophyll proteins in diatom cells revealed by their electrochromic response and fluorescence and linear dichroism spectra

    Science.gov (United States)

    Szabó, Milán; Premvardhan, Lavanya; Lepetit, Bernard; Goss, Reimund; Wilhelm, Christian; Garab, Győző

    2010-07-01

    In this work, by analyzing the electrochromic transient spectra, the 77 K fluorescence emission and excitation, as well as the linear dichroism (LD) and circular dichroism (CD) spectra of low-light (LL) and high-light (HL) grown Phaeodactylum tricornutum cells, we show that the fucoxanthins (Fx) and fucoxanthin-chlorophyll proteins (FCP) exhibit marked functional heterogeneity. Electrochromic transients reveal that LL and HL cells differ substantially in their relative contents of two Fx forms, which absorb at 501 and 550 nm; they exhibit distinct LD signals but are CD silent. Fluorescence emission and excitation spectra at 77 K reveal that although both forms efficiently transfer excitation energy to Chl a, the red form feeds somewhat more energy to photosystem II than to photosystem I. Similar data obtained in Cyclotella meneghiniana cells suggest that the heterogeneity of the FCP pool, with different Fx forms, plays a role in the regulation of energy utilization in FCP-containing organisms.

  6. [Effects of long-term ozone exposure on chlorophyll a fluorescence and gas exchange of winter-wheat leaves].

    Science.gov (United States)

    Zheng, You-fei; Zhao, Ze; Wu, Rong-jun; Hu, Cheng-da; Liu, Hong-ju

    2010-02-01

    In order to provide basis for evaluating the effects of air pollutant such as O3 on crops yield and food security, the effects of O3 fumigation (ambient air, CK; 100 nL x L(-1), T1; 150 nL x L(-1), T2) on chlorophyll a fluorescence and gas exchange of a field-grown winter-wheat (Triticum aestivum L. Yang Mai 13) in different growing period were conducted via open-top chamber technique in conjunction with Diving-PAM fluorometer and LC pro + photosynthesis system. Results indicated that Fv/Fm caused by T1 was higher than 0.8, while the Pm, qP, (1-qP)/NPQ and Y(NO) were similar to those of CK, the NPQ and Y(NPQ) were increased by 13.5%-29.0% and 13.3%-22.7% respectively due to O3 stress. Under nature light (rapid light curve, RLC) and after dark adaptation (induction curve in steady-state, IC) the Yield of T1 was decreased by 4.6%-7.6% and 11.3%-19.3% respectively, with 8.0%-9.8% and 11.0%-23.1% reductions in Pn, and Gs compared to CK, respectively. In heading stage and blooming stage, the Ls of T, was greater than CK, but in filling stage and mature stage, it became lower compared to CK. The Fv/Fm was slightly lower than 0.8 under T2 treatment, with the Y(NO), (1-qP)/NPQ and c(i) were increased by 37.9%-75.6%, 157.1%-325.8% and 3.4%-18.1% relative to CK. Under RLC and IC condition, the Yield of T2 was respectively decreased by 10.2%-13.6% and 21.4%-29.1%, and the Pn, Ls, qP, Pm, NPQ and Y(NPQ) were decreased by 28.1%-39.9%, 5.2%-21.3%, 15.8%-30.4%, 27.6%-45.6%, 3.3%-52.9% and 5.7%-17.9% in comparison, respectively. Obviously the enhanced O3 causes a significant decrease in the capacity of photosynthesis of winter wheat, and the influence mechanism presents a series of dynamic changes according to growing seasons. The reduction of Fv/Fm under T1 treatment is a response of PS II reaction center to the increase of NPQ, and the decrease in Pn and Yield is a consequence of protective adjustment, by this approach, the antioxidant system and energy dissipation mechanism can

  7. Use of chlorophyll a fluorescence to detect the effect of microcystins on photosynthesis and photosystem II energy fluxes of green algae.

    Science.gov (United States)

    Perron, Marie-Claude; Qiu, Baosheng; Boucher, Nathalie; Bellemare, François; Juneau, Philippe

    2012-04-01

    The phenomenon of cyanobacteria bloom occurs widely in lakes, reservoirs, ponds and slow flowing rivers. Those blooms can have important repercussions, at once on recreational and commercial activities but also on the health of animals and human beings. Indeed, many species are known to produce toxins which are released in water mainly at cellular death. The cyanotoxin most frequently encountered is the microcystin (MC), a hepatotoxin which counts more than 70 variants. The use of fast tests for the detection of this toxin is thus a necessity for the protection of the ecosystems and the human health. A promising method for their detection is a bioassay based on the chlorophyll a fluorescence of algae. Many studies have shown that algae are sensible to diverse pollutants, but were almost never used for cyanotoxins. Therefore, our goals were to evaluate the effect of microcystin on the fluorescence of different species of algae and how it can affect the flow of energy through photosystem II. To reach these objectives, we exposed four green algae (Scenedesmus obliquus CPCC5, Chlamydomonas reinhardtii CC125, Pseudokirchneriella subcapitata CPCC37 and Chlorella vulgaris CPCC111) to microcystin standards (variants MC-LF, LR, RR, YR) and to microcystin extracted from Microcystis aeruginosa (CPCC299), which is known to produce mainly MC-LR. Chlorophyll a fluorescence was measured by PEA (Plant Efficiency Analyzer) and LuminoTox. The results of our experiment showed that microcystins affect the photosynthetic efficiency and the flow of energy through photosystem II from 0.01 μg/mL, within only 15 min. From exposure to standard of microcystin, we showed that MC-LF was the most potent variant, followed by MC-YR, LR and RR. Moreover, green algae used in this study demonstrated different sensitivity to MCs, S. obliquus being the more sensitive. We finally demonstrated that LuminoTox was more sensitive to MCs than parameters measured with PEA, although the latter brings

  8. On the origin of the slow M-T chlorophyll a fluorescence decline in cyanobacteria: interplay of short-term light-responses.

    Science.gov (United States)

    Bernát, Gábor; Steinbach, Gábor; Kaňa, Radek; Govindjee; Misra, Amarendra N; Prašil, Ondřej

    2017-10-31

    The slow kinetic phases of the chlorophyll a fluorescence transient (induction) are valuable tools in studying dynamic regulation of light harvesting, light energy distribution between photosystems, and heat dissipation in photosynthetic organisms. However, the origin of these phases are not yet fully understood. This is especially true in the case of prokaryotic oxygenic photoautotrophs, the cyanobacteria. To understand the origin of the slowest (tens of minutes) kinetic phase, the M-T fluorescence decline, in the context of light acclimation of these globally important microorganisms, we have compared spectrally resolved fluorescence induction data from the wild type Synechocystis sp. PCC 6803 cells, using orange (λ = 593 nm) actinic light, with those of mutants, ΔapcD and ΔOCP, that are unable to perform either state transition or fluorescence quenching by orange carotenoid protein (OCP), respectively. Our results suggest a multiple origin of the M-T decline and reveal a complex interplay of various known regulatory processes in maintaining the redox homeostasis of a cyanobacterial cell. In addition, they lead us to suggest that a new type of regulatory process, operating on the timescale of minutes to hours, is involved in dissipating excess light energy in cyanobacteria.

  9. Effect of Different Light Qualities on Growth, Pigment Content, Chlorophyll Fluorescence, and Antioxidant Enzyme Activity in the Red Alga Pyropia haitanensis (Bangiales, Rhodophyta

    Directory of Open Access Journals (Sweden)

    Huanyang Wu

    2016-01-01

    Full Text Available Spectral light changes evoke different morphogenetic and photosynthetic responses that can vary among different algae species. The aim of this study is to investigate the photosynthetic characteristics of the red macroalgae grown under different spectrum environments. In this study, Pyropia haitanensis were cultured under blue, red, and green LED and fluorescent tubes light. The growth rate, photopigment composition, chlorophyll fluorescence, and antioxidative enzymes activities in different light spectrums were investigated. The results revealed that growth rate was significantly higher in the thalli grown under blue, green, and fluorescent tubes light. Contents of Chl a and phycobiliprotein in red light were lower among all the growth conditions. Furthermore, a striking increase in SOD and CAT activity was observed in red light treatment along with the NPQ increase. The results revealed that the photosynthetic efficiency and increased growth rate of P. haitanensis benefitted from light spectrums such as blue, green, and fluorescent tubes light by pigment composition and photochemical efficiency manipulation, whereas red light has disadvantageous effects. Accordingly, the results for improving quality and the economic yield of algae species in some extent and the combination of different wavelengths could allow better economic resource exploitation.

  10. Design and daytime performance of laser-induced fluorescence spectrum lidar for simultaneous detection of multiple components, dissolved organic matter, phycocyanin, and chlorophyll in river water.

    Science.gov (United States)

    Saito, Yasunori; Kakuda, Kei; Yokoyama, Mizuho; Kubota, Tomoki; Tomida, Takayuki; Park, Ho-Dong

    2016-08-20

    In this work, we developed mobile laser-induced fluorescence spectrum (LIFS) lidar based on preliminary experiments on the excitation emission matrix of a water sample and a method for reducing solar background light using the synchronous detection technique. The combination of a UV short-pulse laser (355 nm, 6 ns) for fluorescence excitation with a 10-100 ns short-time synchronous detection using a gated image-intensified multi-channel CCD of the fluorescence made the LIFS lidar operation possible even in daytime. The LIFS lidar with this construction demonstrated the potential of natural river/lake water quality monitoring at the Tenryu River/Lake Suwa. Three main components in the fluorescence data of the water, dissolved organic matter, phycocyanin, and chlorophyll, were extracted by spectral analysis using the standard spectral functions of these components. Their concentrations were estimated by adapting experimentally calibrated data. Results of long-term field observations using our LIFS lidar from 2010 to 2012 show the necessity of simultaneous multi-component detection to understand the natural water environment.

  11. Effect of Different Light Qualities on Growth, Pigment Content, Chlorophyll Fluorescence, and Antioxidant Enzyme Activity in the Red Alga Pyropia haitanensis (Bangiales, Rhodophyta).

    Science.gov (United States)

    Wu, Huanyang

    2016-01-01

    Spectral light changes evoke different morphogenetic and photosynthetic responses that can vary among different algae species. The aim of this study is to investigate the photosynthetic characteristics of the red macroalgae grown under different spectrum environments. In this study, Pyropia haitanensis were cultured under blue, red, and green LED and fluorescent tubes light. The growth rate, photopigment composition, chlorophyll fluorescence, and antioxidative enzymes activities in different light spectrums were investigated. The results revealed that growth rate was significantly higher in the thalli grown under blue, green, and fluorescent tubes light. Contents of Chl a and phycobiliprotein in red light were lower among all the growth conditions. Furthermore, a striking increase in SOD and CAT activity was observed in red light treatment along with the NPQ increase. The results revealed that the photosynthetic efficiency and increased growth rate of P. haitanensis benefitted from light spectrums such as blue, green, and fluorescent tubes light by pigment composition and photochemical efficiency manipulation, whereas red light has disadvantageous effects. Accordingly, the results for improving quality and the economic yield of algae species in some extent and the combination of different wavelengths could allow better economic resource exploitation.

  12. On the polyphasic quenching kinetics of chlorophyll a fluorescence in algae after light pulses of variable length

    NARCIS (Netherlands)

    Vredenberg, W.J.; Prasil, O.

    2013-01-01

    This study reports on kinetics of the fluorescence decay in a suspension of the alga Scenedesmus quadricauda after actinic illumination. These are monitored as the variable fluorescence signal in the dark following light pulses of variable intensity and duration. The decay reflects the restoration

  13. Photo-electric effects on chlorophyll fluorescence of photosystem II in vivo. Kinetics in absence and presence of valinomycin

    NARCIS (Netherlands)

    Vredenberg, W.J.; Bulychev, A.A.

    2003-01-01

    Fluorescence induction curves (F(t)) in low intensity 1s light pulses have been measured in leaf discs in the presence and absence of valinomycin (VMC). Addition of VMC causes: (i) no effect on the initial fluorescence level Fo and the initial (O-J) phase of F(t) in the 0.01-1 ms time range. (ii) An

  14. Fast repetition rate (FRR) fluorometry: variability of chlorophyll a fluorescence yields in colonies of the corals, Montastraea faveolata (w.) and Diploria labyrinthiformes (h.) recovering from bleaching.

    Science.gov (United States)

    Lombardi; Lesser; Gorbunov

    2000-09-05

    Recently, an underwater version of a fast repetition rate fluorometer (FRRF) was developed for the non-destructive study of fluorescence yields in benthic photoautotrophs. We used an FRRF to study bleached colonies of the corals, Montastraea faveolata and Diploria labyrinthiformes at sites surrounding Lee Stocking Island, Exuma, Bahamas, to assess their recovery from bleaching ( approximately 1 year after the initial bleaching event) induced by elevated temperatures. The steady state quantum yields of chlorophyll a fluorescence (DeltaF'/F'(m)) from photosystem II (PSII) within coral colonies were separated into three categories representing visibly distinct degrees of bleaching ranging from no bleaching to completely bleached areas. Differences in DeltaF'/F'(m) were significantly different from bleached to unbleached regions within colonies. Dark, unbleached regions within colonies exhibited significantly higher DeltaF'/F'(m) values (0.438+/-0.019; mean+/-S.D.) when compared to lighter regions, and occupied a majority of the colonies' surface area (46-73%). Bleached regions exhibited significantly lower DeltaF'/F'(m) (0.337+/-0.014) and covered only 7-25% of the colonies' surface area. The observations from this study suggest that zooxanthellae in bleached regions of a colony exhibit reduced photosynthetic activity as long as one year after a bleaching event and that in situ fluorescence techniques such as FRRF are an effective means of studying coral responses and recovery from natural or anthropogenic stress in a non-destructive manner.

  15. Effect of Drought Stress on Leaf Water Status, Electrolyte Leakage, Photosynthesis Parameters and Chlorophyll Fluorescence of Two Kochia Ecotypes (Kochia scoparia Irrigated With Saline Water

    Directory of Open Access Journals (Sweden)

    A Masoumi

    2012-12-01

    Full Text Available Rainfall deficiency and the development of salinity in Iran are the most important factors for using new salt and drought-resistant plants instead of conventional crops. Kochia species have recently attracted the attention of researchers as a forage and fodder crop in marginal lands worldwide due to its drought and salt tolerant characteristics. This field experiment was performed at the Salinity Research Station of Ferdowsi University of Mashhad, Iran, in a split plot based on randomized complete block design with three replications in 2008. Drought stress, including four levels (control, no irrigation in vegetative stage, no irrigation at reproductive stage and no irrigation at maturity stage for four weeks, and two Kochia ecotypes (Birjand and Borujerd were allocated as main and sub plots, respectively. Relative water content, electrolyte leakage, photosynthesis parameters and chlorophyll fluorescence were assayed every two week from late vegetative stage. Results showed that drought stress decreased significantly measured parameters in plants under stress, in all stages. Plants completely recovered after eliminating stress and rewatering and recovered plants did not show significant difference with control. Electrolyte leaking and chlorophyll fluorescence showed the lowest change among the measured parameters. It can emphasize that resistant to stress conditions in this plant and cell wall is not damaged at this level of stress situation. Birjand ecotype from the arid region, revealed a better response than Borujerd ecotype to drought stress. Probably it returns to initial adaptation of Birjand. In general this plant can recover after severe drought stress well. It is possible to introduce this plant as a new fodder in arid and saline conditions.

  16. The effect of fluorescent nanodiamonds on neuronal survival and morphogenesis

    Science.gov (United States)

    Huang, Yung-An; Kao, Chun-Wei; Liu, Kuang-Kai; Huang, Hou-Syun; Chiang, Ming-Han; Soo, Ching-Ren; Chang, Huan-Cheng; Chiu, Tzai-Wen; Chao, Jui-I.; Hwang, Eric

    2014-11-01

    Nanodiamond (ND) has emerged as a promising carbon nanomaterial for therapeutic applications. In previous studies, ND has been reported to have outstanding biocompatibility and high uptake rate in various cell types. ND containing nitrogen-vacancy centers exhibit fluorescence property is called fluorescent nanodiamond (FND), and has been applied for bio-labeling agent. However, the influence and application of FND on the nervous system remain elusive. In order to study the compatibility of FND on the nervous system, neurons treated with FNDs in vitro and in vivo were examined. FND did not induce cytotoxicity in primary neurons from either central (CNS) or peripheral nervous system (PNS); neither did intracranial injection of FND affect animal behavior. The neuronal uptake of FNDs was confirmed using flow cytometry and confocal microscopy. However, FND caused a concentration-dependent decrease in neurite length in both CNS and PNS neurons. Time-lapse live cell imaging showed that the reduction of neurite length was due to the spatial hindrance of FND on advancing axonal growth cone. These findings demonstrate that FNDs exhibit low neuronal toxicity but interfere with neuronal morphogenesis, and should be taken into consideration when applications involve actively growing neurites (e.g. nerve regeneration).

  17. Chlorophyll Fluorescence in Partially Defoliated Grape Plants (Vitis vinifera L. cv. Chardonnay / Fluorescencia de la Clorofila en Plantas de Uva (Vitis vinifera L. cv. Chardonnay Defoliadas Parcialmente

    Directory of Open Access Journals (Sweden)

    Peña Olmos Jaime Ernesto

    2013-08-01

    Full Text Available The chlorophyll content and fluorescence weredetermined in five-year-old grape plants (Vitis vinifera L. cv.Chardonnay that were subjected to early partial defoliation,in Villa de Leyva, Colombia. The experimental design wascompletely randomized, consisting of two treatments (50%defoliation and control, each with four replications of 35 plants. Every two weeks, one of every two recently-emerged leaves was removed from the non-control plants. The determination of total chlorophyll content was carried out on six leaves per plant using a CCM-200 Plus chlorophyll meter, while chlorophyll fluorescence measurements were taken with one darkadapted leaf per plant using a Junior-PAM fluorometer. Initial fluorescence (Fo, maximum fluorescence (Fm, terminal fluorescence (Ft, variable fluorescence (Fv, electron transport rate (ETR, maximum photochemical quantum yield of PSII (Fv/ Fm, effective photochemical quantum yield of photosystem II (Y(II, photochemical fluorescence quenching coefficient (qP, two non-photochemical quenching coefficients (qN and NPQ,quantum yield of light-induced non-photochemical fluorescence quenching (Y(NPQ, and quantum yield of non-light-induced non-photochemical quenching (Y(NO were measured. The chlorophyll concentration index showed higher values in the defoliated plants. There were no significant differences for the values of Fm, Ft and Fv. Fo was higher in the defoliated plants, while ETR, Fv/Fm and Y(II showed higher values in the control plants. It is evident that a reduction in leaf area modifies thepartitioning of excitation energy destined for photochemicaland non-photochemical processes, thus directly influencing the photosynthetic process of the plants evaluated. / Utilizando un diseño completamente aleatorizado,con dos tratamientos (defoliación al 50% y control y cuatrorepeticiones de 35 plantas cada una, se determinó el contenido y la fluorescencia de la clorofila en plantas de uva, sometidas a defoliación parcial

  18. Gas exchange and chlorophyll fluorescence of pea (Pisum sativum L.) plants in response to ambient ozone at a rural site in Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, I.M.; Basahi, J.M. [Air Pollution Laboratory (APL), Centre of Excellence in Environmental Studies (CEES), King Abdulaziz University, P. O. Box 80216, Jeddah 21589 (Saudi Arabia); Hassan, I.A., E-mail: ihassan_eg@yahoo.com [Air Pollution Laboratory (APL), Centre of Excellence in Environmental Studies (CEES), King Abdulaziz University, P. O. Box 80216, Jeddah 21589 (Saudi Arabia); Department of Botany, Faculty of Science, Alexandria University, 21526 El Shatby, Alexandria (Egypt)

    2014-11-01

    Egyptian pea cultivars (Pisum sativum L. cultivars Little Marvel, Perfection and Victory) grown in open-top chambers were exposed to either charcoal-filtered (FA) or non-filtered air (NF) for five consecutive years (2009–2013) at a rural site in northern Egypt. Net photosynthetic rates (P{sub N}), stomatal conductance (g{sub s}), intercellular CO{sub 2} (C{sub i}) and chlorophyll fluorescence were measured. Ozone (O{sub 3}) was found to be the most prevalent pollutant common at the rural site and is suspected to be involved in the alteration of the physiological parameters measured in the present investigation. P{sub N} of different cultivars were found to respond similarly; decreases of 23, 29 and 39% were observed in the cultivars Perfection, Little Marvel and Victory, respectively (averaged over the five years) due to ambient O{sub 3}. The maximum impairment in P{sub N} was recorded in the cultivar Victory (46%) in 2013 when the highest O{sub 3} levels were recorded (90 nL L{sup −1}). The average stomatal conductance decreased by 20 and 18% in the cultivars Little Marvel and Perfection, respectively, while the average stomatal conductance increased on average by 27% in the cultivar Victory. A significant correlation was found between P{sub N} and C{sub i}, indicating the importance of non-stomatal limitations of photosynthesis, especially in the cultivar Victory. The P{sub N} vs. Ci curves were fitted to a non-rectangular hyperbolic model. The actual quantum yield (Φ{sub PSII}) and photochemical quenching coefficient (qP) were significantly decreased in the leaves of plants exposed to NF air. Non-photochemical quenching (NPQ) was increased in all cultivars. Exposure to NF air caused reductions in chlorophyll (Chl a) of 19, 16 and 30% in the Little Marvel, Perfection and Victory cultivars, respectively. - Highlights: • Ozone (O{sub 3}) concentrations recorded were within the ranges of phytotoxicity. • O{sub 3} has a clear influence on the physiological

  19. EFFECT OF Cu AND Mn TOXICITY ON CHLOROPHYLL FLUORESCENCE AND GAS EXCHANGE IN RICE AND SUNFLOWER UNDER DIFFERENT LIGHT INTENSITIES

    Directory of Open Access Journals (Sweden)

    Hajiboland R.

    2007-06-01

    Full Text Available Copper (Cu and manganese (Mn are essential micronutrients for plants, but toxic at high concentrations. Responses of rice (Oryza sativa L. and sunflower (Helianthus annuus L. to toxic concentrations of Mn and Cu (up to 100 μM were studied under three light intensities including low (LL, PPFD=100, intermediate (IL, PPFD=500 and high (HL, PPFD=800 light intensities in hydroponic medium. Rice plants showed higher susceptibility than sunflower to both heavy metals concerning dry matter of shoot and root. Growing under higher light intensity strengthened the effect of Cu toxicity while ameliorated that of Mn, the latter was attributed to the lower Mn accumulation of HL plants in both shoot and root. Chlorophyll content of leaves was influenced negatively only by Cu treatment and that at the highest concentration in the medium (100 μM. Similar with growth results, reduction of net assimilation rate (A was higher in HL than LL plants treated by excess Cu, but in contrast to growth response, reduction was more prominent in sunflower than rice. Excess Mn-induced reduction of A was similar between LL and HL plants and was greater in sunflower than rice. Reduction of A was partly attributable to stomatal limitation, but non-stomatal mechanisms were also involved in this reduction. Copper and Mn treatment did not change the optimal quantum efficiency of PSII in dark-adapted chloroplasts (Fv/Fm ratio, but Fv/F0 was influenced particularly by Cu treatment, the reduction was higher in rice than sunflower and in HL compared to LL plants. Regarding excess Cu and Mn-mediated alterations in chlorophyll concentration, Fv/F0 and Tm values, it was suggested that, Cu and Mn toxicity depress the leaf photosynthetic capacity primarily by causing a significant alteration of the composition and functional competence of the photosynthetic units rather a reduction in the number of photosynthetic units (PSUs per unit leaf area.

  20. Seasonal changes in the photosynthetic capacity and chlorophyll fluorescence in canopy leaves of Quercus crispula in a cool-temperate forest

    Science.gov (United States)

    Tsujimoto, K.; Kato, T.; Nakaji, T.

    2016-12-01

    As well as a proxy of ecosystem level photosynthesis, sun-induced fluorescence (SIF) is expected to be an indicator of plant physiological information in photosynthesis (Frankenberg et al., 2011). Zhang et al. (2014) especially suggested that the SIF can be used to estimate the capacity of RuBP carboxylation, Vcmax, at the ecosystem scale by the simple inversion approach with the combination of both observation and modeling. However, the seasonal pattern of the relationships between SIF and such gas exchange physiological parameters has not been confirmed by the direct field observation, yet. Here, we present the field observation results of both gas exchange based photosynthetic parameters and fluorescence properties of canopy leaves of Japanese oak (Quercus crispula) in a cool-temperate forest. In the Tomakomai experimental forest site (42°40'N, 141°36'E), Hokkaido University in Japan, we conducted the periodical measurements of the seasonality in photosynthetic parameters (Li-6400, Li-Cor, USA) and LED-induced fluorescence yield (USB4000, OceanOptics, USA and mini-PAM, WALZ, Germany) from June to October in 2016. Every two or three weeks, the in-situ single leaf data were collected for 10-16 leaves (consisting of 3-4 leaves x 3-4 individual trees) of Japanese oak at the top of canopy at 15-20m above ground surface with approaching by the tall canopy crane. After the in-situ data acquisition, the leaves are frozen in liquid nitrogen immediately followed by removable from shoots, and are going to be analyzed their chemical properties (ex. Chla, Chlb etc.). By analyzing seasonal pattern of those leaf traits, we are going to show how effectively the chlorophyll fluorescence can assess the carbon assimilation capacity of cool temperate forest.

  1. The 2010 Russian Drought Impact on Satellite Measurements of Solar-Induced Chlorophyll Fluorescence: Insights from Modeling and Comparisons with the Normalized Differential Vegetation Index (NDVI)

    Science.gov (United States)

    Yoshida, Y.; Joiner, J.; Tucker, C.; Berry, J.; Lee, J. -E.; Walker, G.; Reichle, R.; Koster, R.; Lyapustin, A.; Wang, Y.

    2015-01-01

    We examine satellite-based measurements of chlorophyll solar-induced fluorescence (SIF) over the region impacted by the Russian drought and heat wave of 2010. Like the popular Normalized Difference Vegetation Index (NDVI) that has been used for decades to measure photosynthetic capacity, SIF measurements are sensitive to the fraction of absorbed photosynthetically-active radiation (fPAR). However, in addition, SIF is sensitive to the fluorescence yield that is related to the photosynthetic yield. Both SIF and NDVI from satellite data show drought-related declines early in the growing season in 2010 as compared to other years between 2007 and 2013 for areas dominated by crops and grasslands. This suggests an early manifestation of the dry conditions on fPAR. We also simulated SIF using a global land surface model driven by observation-based meteorological fields. The model provides a reasonable simulation of the drought and heat impacts on SIF in terms of the timing and spatial extents of anomalies, but there are some differences between modeled and observed SIF. The model may potentially be improved through data assimilation or parameter estimation using satellite observations of SIF (as well as NDVI). The model simulations also offer the opportunity to examine separately the different components of the SIF signal and relationships with Gross Primary Productivity (GPP).

  2. Ultrasonic selectivity on depressing photosynthesis of cyanobacteria and green algae probed by chlorophyll-a fluorescence transient.

    Science.gov (United States)

    Duan, Zhipeng; Tan, Xiao; Li, Niegui

    2017-10-01

    Ultrasound can inhibit cyanobacterial growth through rupturing cells, but this pathway frequently has the risk to release intercellular toxin (e.g., microcystin). Depressing photosynthesis without cell disruption may provide a new strategy to control cyanobacterial blooms using ultrasound, especially Microcystis blooms. In this work, Microcystis aeruginosa (toxic cyanobacteria) and Chlorella pyrenoidosa (typical green algae) were chosen as model microalgae to verify this hypothesis. Results showed that ultrasound has the ability to inhibit cyanobacterial photosynthesis significantly and selectively. Specifically, sonication damaged Q A , a tightly bound one-electron acceptor, and blocked electron flow at Q B , a two-electron acceptor, in the photosystem II (PSII) of M. aeruginosa when it was exposed for 60 s (35 kHz, 0.043 W/cm 3 ). Moreover, 44.8% of the reaction centers (RCs) in the PSII of M. aeruginosa were transferred into inactive ones (RC si s), and the cell concentration decreased by 32.5% after sonication for 300 s. By contrast, only 7.9% of RC si occurred in C. pyrenoidosa, and cell concentration and chlorophyll-a content reduced by 18.7% and 9.3%, respectively. Differences in both species (i.e., cell structures) might be responsible for the varying levels to sonication. This research suggests that cyanobacteria, especially Microcystis, could be controlled by ultrasound via damaging their PSIIs.

  3. Root endophytic fungus Piriformospora indica affected growth, cadmium partitioning and chlorophyll fluorescence of sunflower under cadmium toxicity.

    Science.gov (United States)

    Shahabivand, Saleh; Parvaneh, Azar; Aliloo, Ali Asghar

    2017-11-01

    Cadmium (Cd) pollution in the soil threatens the quality of environmental health, and deleteriously affects physiological activities of crops. Symbiosis of endophytic fungi with various plants is a promising manner to improving numerous plant characteristics and remediating heavy metal-polluted soils. In this pot experiment, the influence of root endophyte fungus Piriformospora indica on growth, physiological parameters and organs Cd accumulation in sunflower cv. Zaria plants under the toxic levels of Cd (0, 40, 80 and 120mg/kg soil) were studied. Increasing Cd concentration in the soil reduced growth parameters, chlorophyll (Chl) a and Chl b contents, and Fv/Fm and ETR (electron transport rate) values, but increased root, stem and leaf Cd accumulation, and proline content. The presence of P. indica significantly enhanced growth, Chl a, Chl b and proline contents, and Fv/Fm and ETR values. Compared to non-inoculated ones, P. indica-inoculated plants had higher Cd accumulation in root, whereas lower Cd accumulation in stem and leaf. The present study strongly supports the established ability of P. indica to alleviate Cd toxicity by improving the physiological status in sunflower. Furthermore, this endophyte fungus can be useful for Cd phyto-stabilization in sunflower roots in contaminated soils. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Acclimation of shade-tolerant and light-resistant Tradescantia species to growth light: chlorophyll a fluorescence, electron transport, and xanthophyll content.

    Science.gov (United States)

    Mishanin, Vladimir I; Trubitsin, Boris V; Patsaeva, Svetlana V; Ptushenko, Vasily V; Solovchenko, Alexei E; Tikhonov, Alexander N

    2017-09-01

    In this study, we have compared the photosynthetic characteristics of two contrasting species of Tradescantia plants, T. fluminensis (shade-tolerant species), and T. sillamontana (light-resistant species), grown under the low light (LL, 50-125 µmol photons m(-2) s(-1)) or high light (HL, 875-1000 µmol photons m(-2) s(-1)) conditions during their entire growth period. For monitoring the functional state of photosynthetic apparatus (PSA), we measured chlorophyll (Chl) a emission fluorescence spectra and kinetics of light-induced changes in the heights of fluorescence peaks at 685 and 740 nm (F 685 and F 740). We also compared the light-induced oxidation of P700 and assayed the composition of carotenoids in Tradescantia leaves grown under the LL and HL conditions. The analyses of slow induction of Chl a fluorescence (SIF) uncovered different traits in the LL- and HL-grown plants of ecologically contrasting Tradescantia species, which may have potential ecophysiological significance with respect to their tolerance to HL stress. The fluorometry and EPR studies of induction events in chloroplasts in situ demonstrated that acclimation of both Tradescantia species to HL conditions promoted faster responses of their PSA as compared to LL-grown plants. Acclimation of both species to HL also caused marked changes in the leaf anatomy and carotenoid composition (an increase in Violaxanthin + Antheraxantin + Zeaxanthin and Lutein pools), suggesting enhanced photoprotective capacity of the carotenoids in the plants grown in nature under high irradiance. Collectively, the results of the present work suggest that the mechanisms of long-term PSA photoprotection in Tradescantia are based predominantly on the light-induced remodeling of pigment-protein complexes in chloroplasts.

  5. Gas exchange and chlorophyll fluorescence of pea (Pisum sativum L.) plants in response to ambient ozone at a rural site in Egypt.

    Science.gov (United States)

    Ismail, I M; Basahi, J M; Hassan, I A

    2014-11-01

    Egyptian pea cultivars (Pisum sativum L. cultivars Little Marvel, Perfection and Victory) grown in open-top chambers were exposed to either charcoal-filtered (FA) or non-filtered air (NF) for five consecutive years (2009-2013) at a rural site in northern Egypt. Net photosynthetic rates (PN), stomatal conductance (gs), intercellular CO2 (Ci) and chlorophyll fluorescence were measured. Ozone (O3) was found to be the most prevalent pollutant common at the rural site and is suspected to be involved in the alteration of the physiological parameters measured in the present investigation. PN of different cultivars were found to respond similarly; decreases of 23, 29 and 39% were observed in the cultivars Perfection, Little Marvel and Victory, respectively (averaged over the five years) due to ambient O3. The maximum impairment in PN was recorded in the cultivar Victory (46%) in 2013 when the highest O3 levels were recorded (90 nL L(-1)). The average stomatal conductance decreased by 20 and 18% in the cultivars Little Marvel and Perfection, respectively, while the average stomatal conductance increased on average by 27% in the cultivar Victory. A significant correlation was found between PN and Ci, indicating the importance of non-stomatal limitations of photosynthesis, especially in the cultivar Victory. The PN vs. Ci curves were fitted to a non-rectangular hyperbolic model. The actual quantum yield (ΦPSII) and photochemical quenching coefficient (qP) were significantly decreased in the leaves of plants exposed to NF air. Non-photochemical quenching (NPQ) was increased in all cultivars. Exposure to NF air caused reductions in chlorophyll (Chl a) of 19, 16 and 30% in the Little Marvel, Perfection and Victory cultivars, respectively. Copyright © 2014. Published by Elsevier B.V.

  6. Chlorophyll Fluorescence and Gas Exchanges in 'Abbé Fétel'and 'Conference' Pears Stored in Atmosphere Cynamically Controlled with the Aid of Fluorescence Sensors

    NARCIS (Netherlands)

    Eccher Zerbini, P.C.; Grassi, M.

    2010-01-01

    A new technology for monitoring the physiological status of fruit during storage (HarvestWatch™ system with FIRM™ sensors, Satlantic, Canada) was used to detect anaerobic stress in pears by the increase in fluorescence response (Falpha). Two pear cultivars were studied: ‘Conference’, a long-term

  7. Remote monitoring of chlorophyll fluorescence in two reef corals during the 2005 bleaching event at Lee Stocking Island, Bahamas

    Science.gov (United States)

    Manzello, D.; Warner, M.; Stabenau, E.; Hendee, J.; Lesser, M.; Jankulak, M.

    2009-03-01

    Zooxanthellae fluorescence was measured in situ, remotely, and in near real-time with a pulse amplitude modulated (PAM) fluorometer for a colony of Siderastrea siderea and Agaricia tenuifolia at Lee Stocking Island, Bahamas during the Caribbean-wide 2005 bleaching event. These colonies displayed evidence of photosystem II (PS II) inactivation coincident with thermal stress and seasonally high doses of solar radiation. Hurricane-associated declines in temperature and light appear to have facilitated the recovery of maximum quantum yield of PS II within these two colonies, although both corals responded differently to individual storms. PAM fluorometry, coupled with long-term measurement of in situ light and temperature, provides much more detail of coral photobiology on a seasonal time scale and during possible bleaching conditions than sporadic, subjective, and qualitative observations. S. siderea displayed evidence of PS II inactivation over a month prior to the issuing of a satellite-based, sea surface temperature (SST) bleaching alert by the National Oceanic and Atmospheric Administration (NOAA). In fact, recovery had already begun in S. siderea when the bleaching alert was issued. Fluorescence data for A. tenuifolia were difficult to interpret because the shaded parts of a colony were monitored and thus did not perfectly coincide with thermal stress and seasonally high doses of solar radiation as in S. siderea. These results further emphasize the limitations of solely monitoring SST (satellite or in situ) as a bleaching indicator without considering the physiological status of coral-zooxanthellae symbioses.

  8. Effects of ambient versus reduced UV-B radiation on high arctic ¤Salix arctica¤ assessed by measurements and calculations of chlorophyll a fluorescence parameters from fluorescence transients

    DEFF Research Database (Denmark)

    Albert, K.R.; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2005-01-01

    A UV-B exclusion-experiment was conducted in the high Arctic Zackenberg, NE Greenland, in which Salix arctica leaves during most of the growing season were fixed perpendicular to the solar zenith angle, thereby receiving maximal solar radiation. Covered with Teflon and Mylar foil, the leaves...... of evaluating the relative importance of UV-B of donor and acceptor side capacity in Photosystem II. In conclusion, the experimental set-up and non-invasive measurements proved to be a sensitive method to screen for effects of UV-B stress....... received approximately 90 and 40% of the ambient UV-B irradiance, respectively. The effects were examined through recordings of chlorophyll a fluorescence transients, determination of biomass and analysis of total carbon and nitrogen content and amount of soluble flavonoids in the leaves. The processing...

  9. Photoelectric effects on chlorophyll fluorescence of photosystem II in vivo. Kinetics in the absence and presence of valinomycin.

    Science.gov (United States)

    Vredenberg, Wim J; Bulychev, Alexander

    2003-08-01

    Fluorescence induction curves (F(t)) in low intensity 1s light pulses have been measured in leaf discs in the presence and absence of valinomycin (VMC). Addition of VMC causes: (i) no effect on the initial fluorescence level Fo and the initial (O-J) phase of F(t) in the 0.01-1 ms time range. (ii) An approximately 10% decrease in the maximal fluorescence Fm in the light reached at the P level in the O-J-I-P induction curve. (iii) Nearly twofold increase in the rate and extent of the F(t) rise in the J-I phase in the 1-50 ms time range. (iv) A 60-70% decrease in the rise (I-P phase) in the 50-1000 ms time range with no appreciable effect, if at all, on the rate. System analysis of F(t) in terms of rate constants of electron transfer at donor and acceptor sides have been done using the Three State Trapping Model (TSTM). This reveals that VMC causes: (i) no, or very little effect on rate constants of e-transfer reactions powered by PSII. (ii) A manifold lower rate constant of radical pair recombination (k(-1)) in the light as compared to that in the control. The low rate constant of radical pair recombination in the reaction center (RC) in the presence of VMC is reflected by a substantial increase in the nonzero trapping efficiency in RCs in which the primary quinone acceptor (Q(A)) is reduced (semi-open centers). This causes an increase in their rate of closure and in the overall trapping efficiency. Data suggest evidence that membrane chaotropic agents like VMC abolish the stimulation of the rate constant of radical pair recombination by light. This light stimulation that becomes apparent as an increase in Fo has been documented before [Biophys. J. 79 (2000) 26]. It has been ascribed to effects of (changes in) local electric fields in the vicinity of the RC. The decrease of the I-P phase is attributed to a decrease in the photoelectric trans-thylakoid potential in the presence of VMC. Such effects have been hypothesized and illustrated.

  10. Chlorophyll a fluorescence, under half of the adaptive growth-irradiance, for high-throughput sensing of leaf-water deficit in Arabidopsis thaliana accessions

    Directory of Open Access Journals (Sweden)

    Kumud B. Mishra

    2016-11-01

    Full Text Available Abstract Background Non-invasive and high-throughput monitoring of drought in plants from its initiation to visible symptoms is essential to quest drought tolerant varieties. Among the existing methods, chlorophyll a fluorescence (ChlF imaging has the potential to probe systematic changes in photosynthetic reactions; however, prerequisite of dark-adaptation limits its use for high-throughput screening. Results To improve the throughput monitoring of plants, we have exploited their light-adaptive strategy, and investigated possibilities of measuring ChlF transients under low ambient irradiance. We found that the ChlF transients and associated parameters of two contrasting Arabidopsis thaliana accessions, Rsch and Co, give almost similar information, when measured either after ~20 min dark-adaptation or in the presence of half of the adaptive growth-irradiance. The fluorescence parameters, effective quantum yield of PSII photochemistry (ΦPSII and fluorescence decrease ratio (R FD resulting from this approach enabled us to differentiate accessions that is often not possible by well-established dark-adapted fluorescence parameter maximum quantum efficiency of PSII photochemistry (F V/F M. Further, we screened ChlF transients in rosettes of well-watered and drought-stressed six A. thaliana accessions, under half of the adaptive growth-irradiance, without any prior dark-adaptation. Relative water content (RWC in leaves was also assayed and compared to the ChlF parameters. As expected, the RWC was significantly different in drought-stressed from that in well-watered plants in all the six investigated accessions on day-10 of induced drought; the maximum reduction in the RWC was obtained for Rsch (16%, whereas the minimum reduction was for Co (~7%. Drought induced changes were reflected in several features of ChlF transients; combinatorial images obtained from pattern recognition algorithms, trained on pixels of image sequence, improved the contrast

  11. Estresse salino em duas variedades de cana-de-açúcar: enzimas do sistema antioxidativo e fluorescência da clorofila Salinity stress in two varieties of sugar cane: enzymes of the antioxidant system and chlorophyll fluorescence

    Directory of Open Access Journals (Sweden)

    Lilia Willadino

    2011-06-01

    Full Text Available O Brasil destaca-se por ser o maior produtor de cana-de-açúcar (Saccharum officinarum L. e por dominar todos os estágios da tecnologia de produção de açúcar e etanol. Atualmente se observa a expansão dessa cultura para a região semiárida brasileira, a qual apresenta solos propensos à salinização. O presente trabalho objetivou avaliar a resposta à salinidade de duas variedades de cana-de-açúcar. O ensaio foi implantado em casa de vegetação, em delineamento inteiramente casualizado, em esquema fatorial 2 x 8 com cinco repetições, correspondendo a duas variedades de cana-de-açúcar (RB867515 e RB863129 e oito níveis de NaCl (0; 25; 50; 75; 100; 125; 150; 200 mM de NaCl. A salinidade induziu aumento na fluorescência e diminuição na concentração de clorofila em ambas as variedades. A redução da clorofila, entretanto, foi maior na variedade RB867515. Observou-se, nesta mesma variedade, aumento da atividade da peroxidase do ascorbato (APX e da catalase (CAT, enquanto na variedade RB863129 ocorreu redução na atividade dessas enzimas. Esses resultados indicam que a variedade RB867515 apresenta um mecanismo mais eficiente na proteção da planta contra danos no aparato fotoquímico e contra a ação de espécies reativas de oxigênio, em particular o H2O2.Brazil is seen as being the largest producer of sugarcane (Saccharum officinarum L. and of mastering all stages in the production of sugar and ethanol. Currently this production is being expanded into the semi-arid regions of Brazil, where there are soil-types prone to salinity. This study aimed to evaluate the response to salinity in two sugarcane genotypes, RB867515 and RB863129. Salinity caused an increase in chlorophyll fluorescence and a reduction of chlorophyll concentration in both varieties. The reduction of chlorophyll however was higher in RB867515. In this same type, an increase in the activity of ascorbate peroxidase (APX and catalase (CAT was observed, while in

  12. Comparative assessment of single and joint effects of diuron and Irgarol 1051 on Arctic and temperate microalgae using chlorophyll a fluorescence imaging

    KAUST Repository

    Kottuparambil, Sreejith

    2017-02-06

    Ship groundings and ice-breakers can cause pollution of the polar environment with antifouling biocides such as diuron and Irgarol 1051. The present study used pulse amplitude modulated fluorometry to compare single and joint toxicities of diuron and Irgarol 1051 on two freshwater taxa of microalgae (Chlorella and Chlamydomonas) originating from Arctic and temperate regions. 30min acute toxicity tests using chlorophyll a (Chl a) fluorescence revealed that Arctic strains of microalgae were more sensitive to herbicides than their temperate counterparts. Diuron and Irgarol 1051 had equal toxicities in the Arctic species, while Irgarol 1051 was more toxic (EC50=5.55–14.70μgL−1) than diuron (EC50=12.90–>40μgL−1) in the temperate species. Toxicity assessment of various mixtures of diuron and Irgarol 1051 revealed antagonistic, additive, and synergistic effects. Our data suggest that herbicides can adversely affect photosynthesis in Arctic microalgae at relatively low levels, and their impact can increase under complex mixture conditions.

  13. Monitoring and Assessing the 2012 Drought in the Great Plains: Analyzing Satellite-Retrieved Solar-Induced Chlorophyll Fluorescence, Drought Indices, and Gross Primary Production

    Directory of Open Access Journals (Sweden)

    Siheng Wang

    2016-01-01

    Full Text Available We examined the relationship between satellite measurements of solar-induced chlorophyll fluorescence (SIF and several meteorological drought indices, including the multi-time-scale standard precipitation index (SPI and the Palmer drought severity index (PDSI, to evaluate the potential of using SIF to monitor and assess drought. We found significant positive relationships between SIF and drought indices during the growing season (from June to September. SIF was found to be more sensitive to short-term SPIs (one or two months and less sensitive to long-term SPI (three months than were the normalized difference vegetation index (NDVI or the normalized difference water index (NDWI. Significant correlations were found between SIF and PDSI during the growing season for the Great Plains. We found good consistency between SIF and flux-estimated gross primary production (GPP for the years studied, and synchronous declines of SIF and GPP in an extreme drought year (2012. We used SIF to monitor and assess the drought that occurred in the Great Plains during the summer of 2012, and found that although a meteorological drought was experienced throughout the Great Plains from June to September, the western area experienced more agricultural drought than the eastern area. Meanwhile, SIF declined more significantly than NDVI during the peak growing season. Yet for senescence, during which time the reduction of NDVI still went on, the reduction of SIF was eased. Our work provides an alternative to traditional reflectance-based vegetation or drought indices for monitoring and assessing agricultural drought.

  14. Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon Flux Measurements of Montanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone

    Directory of Open Access Journals (Sweden)

    Alexander Ač

    2012-01-01

    Full Text Available We explored ability of reflectance vegetation indexes (VIs related to chlorophyll fluorescence emission (686/630, 740/800 and de-epoxidation state of xanthophyll cycle pigments (PRI, calculated as (531−570/(531−570 to track changes in the CO2 assimilation rate and Light Use Efficiency (LUE in montane grassland and Norway spruce forest ecosystems, both at leaf and also canopy level. VIs were measured at two research plots using a ground-based high spatial/spectral resolution imaging spectroscopy technique. No significant relationship between VIs and leaf light-saturated CO2 assimilation (MAX was detected in instantaneous measurements of grassland under steady-state irradiance conditions. Once the temporal dimension and daily irradiance variation were included into the experimental setup, statistically significant changes in VIs related to tested physiological parameters were revealed. ΔPRI and Δ(686/630 of grassland plant leaves under dark-to-full sunlight transition in the scale of minutes were significantly related to MAX (2=0.51. In the daily course, the variation of VIs measured in one-hour intervals correlated well with the variation of Gross Primary Production (GPP, Net Ecosystem Exchange (NEE, and LUE estimated via the eddy-covariance flux tower. Statistical results were weaker in the case of the grassland ecosystem, with the strongest statistical relation of the index 686/630 with NEE and GPP.

  15. Toxic effects of amoxicillin on the photosystem II of Synechocystis sp. characterized by a variety of in vivo chlorophyll fluorescence tests

    Energy Technology Data Exchange (ETDEWEB)

    Pan Xiangliang [Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumuqi, 830011 (China); State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002 (China); Deng Chunnuan [Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Changchun, 130012 (China); Yunnan Normal University, Kunming 650092 (China); Zhang Daoyong [Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumuqi, 830011 (China); State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002 (China)], E-mail: zhangdaoyong@vip.gyig.ac.cn; Wang Jianlong [Institute of Nuclear Energy and Technology, Tsinghua University, Beijing, 100083 (China); Mu Guijin [Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumuqi, 830011 (China); Chen Ying [Yunnan Normal University, Kunming 650092 (China)

    2008-09-29

    Amoxicillin is one of the widely used antibiotics of environmental concern. This study shows that amoxicillin has toxic effects on the photosynthesis of Synechocystis sp. Its inhibitory effects on photosystem II (PSII) of Synechocystis sp. were investigated by using a variety of in vivo chlorophyll fluorescence tests. The inhibitory effects of amoxicillin on PSII activity of Synechocystis sp. are concentration-dependent. Amoxicillin exposure leads to slowing down of electron transport on both donor side and acceptor side and causes accumulation of P680{sup +}. Q{sub A}{sup -} reoxidation test revealed that amoxicillin hinders electron transfer from Q{sub A}{sup -} to Q{sub B}/Q{sub B}{sup -} and more Q{sub A}{sup -} is oxidized through S{sub 2}(Q{sub A}Q{sub B}){sup -} charge recombination. Analysis of PSII heterogeneity demonstrated that an exposure to amoxicillin increases the proportion of inactive PSII (PSII{sub X}) centers and the proportion of PSII centers with small antenna (PSII{beta}). These changes finally result in deterioration of full photosynthesis performance.

  16. Temporal consistency between gross primary production and solar-induced chlorophyll fluorescence in the ten most populous megacity areas over years.

    Science.gov (United States)

    Cui, Yaoping; Xiao, Xiangming; Zhang, Yao; Dong, Jinwei; Qin, Yuanwei; Doughty, Russell B; Zhang, Geli; Wang, Jie; Wu, Xiaocui; Qin, Yaochen; Zhou, Shenghui; Joiner, Joanna; Moore, Berrien

    2017-11-02

    The gross primary production (GPP) of vegetation in urban areas plays an important role in the study of urban ecology. It is difficult however, to accurately estimate GPP in urban areas, mostly due to the complexity of impervious land surfaces, buildings, vegetation, and management. Recently, we used the Vegetation Photosynthesis Model (VPM), climate data, and satellite images to estimate the GPP of terrestrial ecosystems including urban areas. Here, we report VPM-based GPP (GPPvpm) estimates for the world's ten most populous megacities during 2000-2014. The seasonal dynamics of GPPvpm during 2007-2014 in the ten megacities track well that of the solar-induced chlorophyll fluorescence (SIF) data from GOME-2 at 0.5° × 0.5° resolution. Annual GPPvpm during 2000-2014 also shows substantial variation among the ten megacities, and year-to-year trends show increases, no change, and decreases. Urban expansion and vegetation collectively impact GPP variations in these megacities. The results of this study demonstrate the potential of a satellite-based vegetation photosynthesis model for diagnostic studies of GPP and the terrestrial carbon cycle in urban areas.

  17. A new method to estimate photosynthetic parameters through net assimilation rate-intercellular space CO2 concentration (A-Ci ) curve and chlorophyll fluorescence measurements.

    Science.gov (United States)

    Moualeu-Ngangue, Dany P; Chen, Tsu-Wei; Stützel, Hartmut

    2017-02-01

    Gas exchange (GE) and chlorophyll fluorescence (CF) measurements are widely used to noninvasively study photosynthetic parameters, for example the rates of maximum Rubisco carboxylation (Vcmax ), electron transport rate (J), daytime respiration (Rd ) and mesophyll conductance (gm ). Existing methods for fitting GE data (net assimilation rate-intercellular space CO2 concentration (A-Ci ) curve) are based on two assumptions: gm is unvaried with CO2 concentration in the intercellular space (Ci ); and light absorption (α) and the proportion of quanta absorbed by photosystem II (β) are constant in the data set. These may result in significant bias in estimating photosynthetic parameters. To avoid the above-mentioned hypotheses, we present a new method for fitting A-Ci curves and CF data simultaneously. This method was applied to a data set obtained from cucumber (Cucumis sativus) leaves of various leaf ages and grown under eight different light conditions. The new method had significantly lower root mean square error and a lower rate of failures compared with previously published methods (6.72% versus 24.1%, respectively) and the effect of light conditions on Vcmax and J was better observed. Furthermore, the new method allows the estimation of a new parameter, the fraction of incoming irradiance harvested by photosystem II, and the dependence of gm on Ci . © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  18. Use of the method of measurement of chlorophyll fluorescence to determine the phytotoxicity of mesotrione in poppy (Papaver somniferum in relation to application factors

    Directory of Open Access Journals (Sweden)

    Jana Filová

    2010-01-01

    Full Text Available The aim of the research work was to evaluate phytotoxicity of mesotrione in poppy (Papaver somniferum. The amount of spraying water (150, 300 and 450 l per hectare was compared as well. In the end, the different growth stimulators (Atonik – 0.6 l . ha−1, Route – 0.8 l . ha−1 and the adjuvants (Atplus 463 – 0.5% solution, Silwet 77 – 0.1 l . ha−1 wre tested. Degree of phytotoxicity of individual va­riants was assessed by measuring chlorophyll fluorescence (parameter: maximum quantum yield of electron transport in photosystem II - QY in 1st to 21st day after treatment. The results showed that the application of mesotrione caused phytotoxicity on poppy plants. The most significant phy­to­to­xi­ci­ty is evident at doses of 450 l spraying water per hectare. Addition of growth stimulators and adjuvants increases the phytotoxicity (decreases the value of QY compared to the herbicide application itself. The mesotrione reduced the weight of dry plants by 15 % (150 l of spraying water, 1 % (300 l of spraying water and 64 % (450 l of spraying water compared to control variant.

  19. Photochemical properties in flag leaves of a super-high-yielding hybrid rice and a traditional hybrid rice (Oryza sativa L.) probed by chlorophyll a fluorescence transient.

    Science.gov (United States)

    Zhang, Meiping; Shan, YongJie; Kochian, Leon; Strasser, Reto J; Chen, GuoXiang

    2015-12-01

    Chlorophyll a fluorescence of flag leaves in a super-high-yielding hybrid rice (Oryza sativa L.) LYPJ, and a traditional hybrid rice SY63 cultivar with lower grain yield, which were grown in the field, were investigated from emergence through senescence of flag leaves. As the flag leaf matured, there was an increasing trend in photosynthetic parameters such as quantum efficiency of primary photochemistry ([Formula: see text] Po) and efficiency of electron transport from PS II to PS I (Ψ Eo). The overall photosynthetic performance index (PIABS) was significantly higher in the high-yielding LYPJ compared to SY63 during the entire reproductive stage of the plant, the same to MDA content. However, [Formula: see text] Po(=F V/F M), an indicator of the primary photochemistry of the flag leaf, did not display significant changes with leaf age and was not significantly different between the two cultivars, suggesting that PIABS is a more sensitive parameter than [Formula: see text] Po (=F V/F M) during leaf age for distinguishing between cultivars differing in yield.

  20. An Excel tool for deriving key photosynthetic parameters from combined gas exchange and chlorophyll fluorescence: theory and practice.

    Science.gov (United States)

    Bellasio, Chandra; Beerling, David J; Griffiths, Howard

    2016-06-01

    Combined photosynthetic gas exchange and modulated fluorometres are widely used to evaluate physiological characteristics associated with phenotypic and genotypic variation, whether in response to genetic manipulation or resource limitation in natural vegetation or crops. After describing relatively simple experimental procedures, we present the theoretical background to the derivation of photosynthetic parameters, and provide a freely available Excel-based fitting tool (EFT) that will be of use to specialists and non-specialists alike. We use data acquired in concurrent variable fluorescence-gas exchange experiments, where A/Ci and light-response curves have been measured under ambient and low oxygen. From these data, the EFT derives light respiration, initial PSII (photosystem II) photochemical yield, initial quantum yield for CO2 fixation, fraction of incident light harvested by PSII, initial quantum yield for electron transport, electron transport rate, rate of photorespiration, stomatal limitation, Rubisco (ribulose 1·5-bisphosphate carboxylase/oxygenase) rate of carboxylation and oxygenation, Rubisco specificity factor, mesophyll conductance to CO2 diffusion, light and CO2 compensation point, Rubisco apparent Michaelis-Menten constant, and Rubisco CO2 -saturated carboxylation rate. As an example, a complete analysis of gas exchange data on tobacco plants is provided. We also discuss potential measurement problems and pitfalls, and suggest how such empirical data could subsequently be used to parameterize predictive photosynthetic models. © 2015 John Wiley & Sons Ltd.

  1. Spectral effects of LEDs on chlorophyll fluorescence and pigmentation in Phalaenopsis 'Vivien' and 'Purple Star'

    DEFF Research Database (Denmark)

    Ouzounis, Theoharis; Fretté, Xavier; Ottosen, Carl-Otto

    2015-01-01

    /night temperature, respectively, from January to April 2013. The light treatments were (1) 40% blue in 60% red (40% B/R), (2) 0% blue in 100% red (0% B/R) and (3) white LEDs with 32% blue in white (32% B/W, control), with background daylight under shade screens. The plants were harvested twice for leaf growth...... and pigmentation. There was no clear pattern in the spectral effect on growth since the order of leaf size differed between harvests in March and April. Fv/Fm was in the range of 0.52-0.72, but overall slightly higher in the control, which indicated a permanent downregulation of PSII in the colored treatments....... The fluorescence quenching showed no acclimation to color in 'Purple Star', while 'Vivien' had lower ETR and higher NPQ in the 40% B/R, resembling low light acclimation. The pigmentation showed corresponding spectral response with increasing concentration of lutein while increasing the fraction of blue light...

  2. Fluorescence spectroscopy for assessment of liver transplantation grafts concerning graft viability and patient survival

    Science.gov (United States)

    Vollet Filho, José D.; da Silveira, Marina R.; Castro-e-Silva, Orlando; Bagnato, Vanderlei S.; Kurachi, Cristina

    2015-06-01

    Evaluating transplantation grafts at harvest is essential for its success. Laser-induced fluorescence spectroscopy (LIFS) can help monitoring changes in metabolic/structural conditions of tissue during transplantation. The aim of the present study is to correlate LIFSobtained spectra of human hepatic grafts during liver transplantation with post-operative patients' mortality rate and biochemical parameters, establishing a method to exclude nonviable grafts before implantation. Orthotopic liver transplantation, piggyback technique was performed in 15 patients. LIFS was performed under 408nm excitation. Collection was performed immediately after opening donor's abdominal cavity, after cold perfusion, end of back-table period, and 5 min and 1 h after warm perfusion at recipient. Fluorescence information was compared to lactate, creatinine, bilirubin and INR levels and to survival status. LIFS was sensitive to liver changes during transplantation stages. Study-in-progress; initial results indicate correlation between fluorescence and life/death status of patients.

  3. A framework to quantify the determinants of canopy photosynthesis and carbon uptake using time series of chlorophyll fluorescence

    Science.gov (United States)

    Kellner, J. R.; Cushman, K. C.; Kendrick, J. A.; Silva, C. E.; Wiseman, S. M.; Yang, X.

    2015-12-01

    Uncertainty over the sign and magnitude of environmental forcing agents on fluxes of tropical forest carbon could be reduced with measurements of canopy photosynthesis. But no existing method can quantify photosynthesis within individual plants at scales larger than a few cm. Portable leaf chambers can determine leaf-level gas exchange, and eddy-covariance instruments infer the net ecosystem-atmosphere carbon flux. These endpoints represent an axis of granularity and extent. Single leaf measurements are finely grained, but necessarily limited in extent, and gas exchange for whole landscapes cannot resolve the performance or contributions of individual plants. This limits the ability of scientists to test mechanistic demographic and physiological hypotheses about the drivers of photosynthesis in ecosystems, and therefore to understand the determinants of carbon fluxes between tropical ecosystems and the atmosphere. Here I describe a framework to overcome these challenges using a program of drone-enabled remote sensing measurements of solar-induced fluorescence (SIF) coupled with ground-based physiological studies to understand the determinants of photosynthesis within leaves, individual organisms and large landscapes. The Brown Platform for Autonomous Remote Sensing (BPAR) is a suite of sensors carried by a gas-powered helicopter drone. By conducting frequent, low-altitude flights BPAR can produce VNIR imaging spectroscopy time series with measurements separated by minutes to hours at ground sample distances of 1 cm. The talk will focus on how measurements of SIF at these spatial and temporal scales can be coupled with models to infer the rate of electron transport and carbon assimilation.

  4. Calibration procedures and first dataset of Southern Ocean chlorophyll a profiles collected by elephant seals equipped with a newly developed CTD-fluorescence tags

    Directory of Open Access Journals (Sweden)

    C. Guinet

    2013-02-01

    of these new tags, we are able to assess the 3-dimension distribution of phytoplankton concentration by foraging southern elephant seals. This approach reveals that for the Indian sector of the SO, the surface chlorophyll a (chl a concentrations provided by MODIS were underestimated by a factor 2 compared to chl a concentrations estimated from HPLC corrected in situ fluorescence measurements. The scientific outcomes of this programme include an improved understanding of both the present state and variability in ocean biology, and the accompanying biogeochemistry, as well as the delivery of real-time and open-access data to scientists (doi:10.7491/MEMO.1.

  5. Leaf gas exchange, chlorophyll fluorescence and pigment indexes of Eugenia uniflora L. in response to changes in light intensity and soil flooding.

    Science.gov (United States)

    Mielke, Marcelo S; Schaffer, Bruce

    2010-01-01

    The interactive effects of changing light intensity and soil flooding on the photosynthetic performance of Eugenia uniflora L. (Myrtaceae) seedlings in containers were examined. Two hypotheses were tested: (i) the photosynthetic apparatus of shade-adapted leaves can be rapidly acclimated to high light after transfer from shade to full sun, and (ii) photosynthetic acclimation to changing light intensity may be influenced by soil flooding. Seedlings cultivated in a shade house (40% of full sun, approximately 12 mol m(-)(2) day(-)(1)) for 6 months were transferred to full sun (20-40 mol m(-2) day(-1)) or shade (30% of full sun, approximately 8 mol m(-2) day(-1)) and subjected to soil flooding for 23 days or not flooded. Chlorophyll content index (CCI), chlorophyll fluorescence, leaf weight per area (LWA), photosynthetic light-response curves and leaf reflectance indexes were measured during soil flooding and after plants were unflooded. The CCI values increased throughout the experiment in leaves of shaded plants and decreased in leaves of plants transferred to full sun. There were no significant interactions between light intensity and flooding treatments for most of the variables analyzed, with the exception of Fv/Fm 22 days after plants were flooded and 5 days after flooded plants were unflooded. The light environment significantly affected LWA, and light environment and soil flooding significantly affected the light-saturated gross CO(2) assimilation rate expressed on area and dry weight bases (A(max-area) and A(max-wt), respectively), stomatal conductance of water vapor (g(ssat)) and intrinsic water use efficiency (A/g(s)). Five days after flooded plants were unflooded, the normalized difference vegetation index (NDVI) and the scaled photochemical reflectance index (sPRI) were significantly higher in shade than in sun leaves. Thirty days after transferring plants from the shade house to the light treatment, LWA was 30% higher in sun than in shade leaves, and A

  6. Impact of salt stress (NaCl on growth, chlorophyll content and fluorescence of Tunisian cultivars of chili pepper (Capsicum frutescens L.

    Directory of Open Access Journals (Sweden)

    Kaouther Zhani

    2012-11-01

    Full Text Available Salinity is considered as the most important abiotic stress limiting crop production and plants are known to be able continuing survive under this stress by involving many mechanisms. In this content, the present study was carried out to evaluate the impact of NaCl on some physiological and biochemical parameters in five Tunisian chili pepper (Capsicum frutescens L. cultivars: Tebourba (Tb, Somaa (Sm, Korba (Kb, Awald Haffouzz (AW and Souk jedid (Sj. Thus, an experiment of five months was carried out under greenhouse at Higher Institute of Agronomy, Chott Meriem, Tunisia and stress is induced by NaCl at 7 concentrations (0, 2, 4, 6, 8, 10 and 12g/l. Results showed that increasing salinity stress, for all cultivars, had a negative impact on roots (length, fresh and dry weights and leaves (number and area. Also, chlorophyll (a and b amount in addition to quantium yield (Fv/Fm decreased significantly. However, biosynthesis of proline in leaves is activated. Awlad Haffouzz and Korba cultivars succefully tolerated highest salinity level by accumulating more proline in leaves and maintaining usually higher values in all parameters in opposition to Souk jedid cultivar. Taken together, our data partly explain the mechanism used to ovoid salt stress by pepper plants when excessive in the culture medium.

  7. Trocas gasosas e fluorescência da clorofila em seis cultivares de cafeeiro sob estresse de alumínio Gas exchange and chlorophyll fluorescence in six coffee cultivars under aluminum stress

    Directory of Open Access Journals (Sweden)

    Maria Luiza Freitas Konrad

    2005-01-01

    Full Text Available Em experimento desenvolvido em casa de vegetação e em câmara de crescimento avaliou-se o efeito do alumínio (Al na fotossíntese de seis cultivares de cafeeiro. As plantas foram cultivadas em solução nutritiva aerada continuamente, contendo duas concentrações de Al, 0 e 0,148 mmol L-1, fornecidas como Al2(SO43. Após 97 dias mediram-se as taxas de assimilação de CO2 (A e transpiração (E, a condutância estomática (gs, a concentração interna de CO2 (Ci, eficiência instantânea de carboxilação (fic e variáveis de fluorescência da clorofila. Em todas as cultivares, a presença de Al causou quedas significantes em A, gs, fic, ocorrendo aumento em Ci. Também se observou aumento significativo na fluorescência basal (Fo e queda na eficiência quântica máxima do fotossistema II (Fv/Fm, sugerindo injúrias na estrutura dos tilacóides causadas pelo Al. Na curva de indução de fotossíntese, observou-se que o Al causou queda no coeficiente de extinção fotoquímica da fluorescência e aumento no coeficiente de extinção não fotoquímico. Os resultados desse estudo indicaram que a queda de A foi devida à queda da condutância estomática, nas atividades bioquímicas e fotoquímicas.Experiments were carried out under greenhouse and growth chamber to evaluate the effects of aluminum (Al on several photosynthetic characteristics in six coffee cultivars. Plants were grown in nutrient solution aerated continuously, containing two Al concentration, 0 and 0.148 mmol L-1, supplied as Al2(SO43. After 97 days of treatament, measurements of CO2 assimilation rate (A, transpiration rate (E, stomatal conductance (gs, internal CO2 concentration (Ci, instantaneous carboxylation efficiency (phic and chlorophyll fluorescence related characteristics were performed. All six cultivars showed decrease in A, gs and phic and increase in Ci. The basal chlorophyll fluorescence yield (Fo increased and the maximum quantum efficiency (Fv/Fm decreased

  8. Phytoplankton chlorophyll

    NARCIS (Netherlands)

    van de Poll, W.H.; Kulk, G.; Timmermans, K.R.; Brussaard, C.P.D.; van der Woerd, H.J.; Kehoe, M.J.; Mojica, K.D.A.; Visser, R.J.W.; Rozema, P.D.; Buma, A.G.J.

    2013-01-01

    Relationships between sea surface temperature (SST, > 10 m) and vertical density stratification, nutrient concentrations, and phytoplankton biomass, composition, and chlorophyll a (Chl a) specific absorption were assessed in spring and summer from latitudes 29 to 63 degrees N in the northeast

  9. Estimating Diurnal Courses of Gross Primary Production for Maize: A Comparison of Sun-Induced Chlorophyll Fluorescence, Light-Use Efficiency and Process-Based Models

    Directory of Open Access Journals (Sweden)

    Tianxiang Cui

    2017-12-01

    Full Text Available Accurately quantifying gross primary production (GPP is of vital importance to understanding the global carbon cycle. Light-use efficiency (LUE models and process-based models have been widely used to estimate GPP at different spatial and temporal scales. However, large uncertainties remain in quantifying GPP, especially for croplands. Recently, remote measurements of solar-induced chlorophyll fluorescence (SIF have provided a new perspective to assess actual levels of plant photosynthesis. In the presented study, we evaluated the performance of three approaches, including the LUE-based multi-source data synergized quantitative (MuSyQ GPP algorithm, the process-based boreal ecosystem productivity simulator (BEPS model, and the SIF-based statistical model, in estimating the diurnal courses of GPP at a maize site in Zhangye, China. A field campaign was conducted to acquire synchronous far-red SIF (SIF760 observations and flux tower-based GPP measurements. Our results showed that both SIF760 and GPP were linearly correlated with APAR, and the SIF760-GPP relationship was adequately characterized using a linear function. The evaluation of the modeled GPP against the GPP measured from the tower demonstrated that all three approaches provided reasonable estimates, with R2 values of 0.702, 0.867, and 0.667 and RMSE values of 0.247, 0.153, and 0.236 mg m−2 s−1 for the MuSyQ-GPP, BEPS and SIF models, respectively. This study indicated that the BEPS model simulated the GPP best due to its efficiency in describing the underlying physiological processes of sunlit and shaded leaves. The MuSyQ-GPP model was limited by its simplification of some critical ecological processes and its weakness in characterizing the contribution of shaded leaves. The SIF760-based model demonstrated a relatively limited accuracy but showed its potential in modeling GPP without dependency on climate inputs in short-term studies.

  10. Leaf morphology, photosynthetic performance, chlorophyll fluorescence, stomatal development of lettuce (Lactuca sativa L. exposed to different ratios of red light to blue light

    Directory of Open Access Journals (Sweden)

    Jun eWang

    2016-03-01

    Full Text Available Red and blue light are both vital factors for plant growth and development. We examined how different ratios of red light to blue light (R/B provided by light-emitting diodes affected photosynthetic performance by investigating parameters related to photosynthesis, including leaf morphology, photosynthetic rate, chlorophyll fluorescence, stomatal development, light response curve, and nitrogen content. In this study, lettuce plants (Lactuca sativa L. were exposed to 200 μmol•m-2•s-1 irradiance for a 16 h•d-1 photoperiod under the following six treatments: monochromatic red light (R, monochromatic blue light (B and the mixture of R and B with different R/B ratios of 12, 8, 4, and 1. Leaf photosynthetic capacity (Amax and photosynthetic rate (Pn increased with decreasing R/B ratio until 1, associated with increased stomatal conductance, along with significant increase in stomatal density and slight decrease in stomatal size. Pn and Amax under B treatment had 7.6% and 11.8% reduction in comparison with those under R/B=1 treatment, respectively. The effective quantum yield of PSII and the efficiency of excitation captured by open PSII center were also significantly lower under B treatment than those under the other treatments. Shoot dry weight increased with increasing R/B ratio with the greatest value under R/B=12 treatment. The increase of shoot dry weight was mainly caused by increasing leaf area and leaf number, but no significant difference was observed between R and R/B=12 treatments. Based on the above results, we conclude that quantitative B could promote photosynthetic performance or growth by stimulating morphological and physiological responses, yet there was no positive correlation between Pn and shoot dry weight accumulation.

  11. Space-borne Chlorophyll Fluorescence, Greenness, Vegetation Models and Interannual Variability of Photosynthetic Activity: Spatio-temporal Patterns, Mechanisms, and Environmental Sensitivities

    Science.gov (United States)

    Walther, S.; Guanter, L.; Jung, M.; Frankenberg, C.; Sun, Y.; Forkel, M.; Zhang, Y.; Duveiller, G.; Cescatti, A.; Camps-Valls, G.; Köhler, P.

    2016-12-01

    It is much debated whether respiration or photosynthesis drive net ecosystem productivity andwhich regions contribute strongest to the observed interannual variability (IAV) of the strengthof the land sink. Several studies point to photosynthetic productivity in semi-arid regions as avery important factor influencing atmospheric CO2 variability globally (e.g. Jung et al., 2011;Poulter et al., 2014; Ahlstr ̈ om et al., 2015). Here, we aim at a comprehensive comparison ofthe strength, timing and spatial extent of anomalies of photosynthesis as they are indicated bysatellite observations of greenness, vegetation optical depth, and sun-induced chlorophyll fluo-rescence (SIF). We will compare them to the results of diagnostic, empirical and process-basedvegetation models. Except for the evergreen tropics, the spatio-temporal patterns of monthlydominant vegetation variability are generally consistently shown in semi-arid areas, albeit withdiffering magnitudes between greenness and photosynthesis globally. Relative anomalies (to themean seasonal cycle) are particularly widespread in high northern latitudes. Further researchsteps will include i) the repeated analysis at higher temporal resolution to better refine the dif-ferent time scales of reaction between light-use-efficiency and APAR and between forestedand non-forested ecosystems, ii) investigate on characteristic time scales at which the proxies(dis-)agree and why, iii) study the relative contributions of anomalies in peak and length of thegrowing season to IAV (similar to Xia et al., 2015; Zhou et al., 2016), iv) analyse the proxiesfor possibly differing hydrological sensitivities, and v) vegetation models have long been knownto have very diverse abilities to capture GPP IAV. Our preliminary results confirm this and wewill further study possible limitations and possible ways for improvement of the simulations.

  12. Lutein from Deepoxidation of Lutein Epoxide Replaces Zeaxanthin to Sustain an Enhanced Capacity for Nonphotochemical Chlorophyll Fluorescence Quenching in Avocado Shade Leaves in the Dark1

    Science.gov (United States)

    Förster, Britta; Pogson, Barry James; Osmond, Charles Barry

    2011-01-01

    Leaves of avocado (Persea americana) that develop and persist in deep shade canopies have very low rates of photosynthesis but contain high concentrations of lutein epoxide (Lx) that are partially deepoxidized to lutein (L) after 1 h of exposure to 120 to 350 μmol photons m−2 s−1, increasing the total L pool by 5% to 10% (ΔL). Deepoxidation of Lx to L was near stoichiometric and similar in kinetics to deepoxidation of violaxanthin (V) to antheraxanthin (A) and zeaxanthin (Z). Although the V pool was restored by epoxidation of A and Z overnight, the Lx pool was not. Depending on leaf age and pretreatment, the pool of ΔL persisted for up to 72 h in the dark. Metabolism of ΔL did not involve epoxidation to Lx. These contrasting kinetics enabled us to differentiate three states of the capacity for nonphotochemical chlorophyll fluorescence quenching (NPQ) in attached and detached leaves: ΔpH dependent (NPQΔpH) before deepoxidation; after deepoxidation in the presence of ΔL, A, and Z (NPQΔLAZ); and after epoxidation of A+Z but with residual ΔL (NPQΔL). The capacity of both NPQΔLAZ and NPQΔL was similar and 45% larger than NPQΔpH, but dark relaxation of NPQΔLAZ was slower. The enhanced capacity for NPQ was lost after metabolism of ΔL. The near equivalence of NPQΔLAZ and NPQΔL provides compelling evidence that the small dynamic pool ΔL replaces A+Z in avocado to “lock in” enhanced NPQ. The results are discussed in relation to data obtained with other Lx-rich species and in mutants of Arabidopsis (Arabidopsis thaliana) with increased L pools. PMID:21427278

  13. Leaf Morphology, Photosynthetic Performance, Chlorophyll Fluorescence, Stomatal Development of Lettuce (Lactuca sativa L.) Exposed to Different Ratios of Red Light to Blue Light.

    Science.gov (United States)

    Wang, Jun; Lu, Wei; Tong, Yuxin; Yang, Qichang

    2016-01-01

    Red and blue light are both vital factors for plant growth and development. We examined how different ratios of red light to blue light (R/B) provided by light-emitting diodes affected photosynthetic performance by investigating parameters related to photosynthesis, including leaf morphology, photosynthetic rate, chlorophyll fluorescence, stomatal development, light response curve, and nitrogen content. In this study, lettuce plants (Lactuca sativa L.) were exposed to 200 μmol⋅m(-2)⋅s(-1) irradiance for a 16 h⋅d(-1) photoperiod under the following six treatments: monochromatic red light (R), monochromatic blue light (B) and the mixture of R and B with different R/B ratios of 12, 8, 4, and 1. Leaf photosynthetic capacity (A max) and photosynthetic rate (P n) increased with decreasing R/B ratio until 1, associated with increased stomatal conductance, along with significant increase in stomatal density and slight decrease in stomatal size. P n and A max under B treatment had 7.6 and 11.8% reduction in comparison with those under R/B = 1 treatment, respectively. The effective quantum yield of PSII and the efficiency of excitation captured by open PSII center were also significantly lower under B treatment than those under the other treatments. However, shoot dry weight increased with increasing R/B ratio with the greatest value under R/B = 12 treatment. The increase of shoot dry weight was mainly caused by increasing leaf area and leaf number, but no significant difference was observed between R and R/B = 12 treatments. Based on the above results, we conclude that quantitative B could promote photosynthetic performance or growth by stimulating morphological and physiological responses, yet there was no positive correlation between P n and shoot dry weight accumulation.

  14. Using Different Regression Methods to Estimate Leaf Nitrogen Content in Rice by Fusing Hyperspectral LiDAR Data and Laser-Induced Chlorophyll Fluorescence Data

    Directory of Open Access Journals (Sweden)

    Lin Du

    2016-06-01

    Full Text Available Nitrogen is an essential nutrient element in crop photosynthesis and yield improvement. Thus, it is urgent and important to accurately estimate the leaf nitrogen contents (LNC of crops for precision nitrogen management. Based on the correlation between LNC and reflectance spectra, the hyperspectral LiDAR (HSL system can determine three-dimensional structural parameters and biochemical changes of crops. Thereby, HSL technology has been widely used to monitor the LNC of crops at leaf and canopy levels. In addition, the laser-induced fluorescence (LIF of chlorophyll, related to the histological structure and physiological conditions of green plants, can also be utilized to detect nutrient stress in crops. In this study, four regression algorithms, support vector machines (SVMs, partial least squares (PLS and two artificial neural networks (ANNs, back propagation NNs (BP-NNs and radial basic function NNs (RBF-NNs, were selected to estimate rice LNC in booting and heading stages based on reflectance and LIF spectra. These four regression algorithms were used for 36 input variables, including the reflectance spectral variables on 32 wavelengths and four peaks of the LIF spectra. A feature weight algorithm was proposed to select different band combinations for the LNC retrieval models. The determination coefficient (R2 and the root mean square error (RMSE of the retrieval models were utilized to compare their abilities of estimating the rice LNC. The experimental results demonstrate that (I these four regression methods are useful for estimating rice LNC in the order of RBF-NNs > SVMs > BP-NNs > PLS; (II The LIF data in two forms, including peaks and indices, display potential in rice LNC retrieval, especially when using the PLS regression (PLSR model for the relationship of rice LNC with spectral variables. The feature weighting algorithm is an effective and necessary method to determine appropriate band combinations for rice LNC estimation.

  15. Responses of chlorophyll fluorescence parameters of the facultative halophyte and C3-CAM intermediate species Mesembryanthemum crystallinum to salinity and high irradiance stress.

    Science.gov (United States)

    Broetto, Fernando; Monteiro Duarte, Heitor; Lüttge, Ulrich

    2007-07-01

    Mesembryanthemum crystallinum L. (Aizoaceae) is a facultative annual halophyte and a C(3)-photosynthesis/crassulacean acid metabolism intermediate species currently used as a model plant in stress physiology. Both salinity and high light irradiance stress are known to induce CAM in this species. The present study was performed to provide a diagnosis of alterations at the photosystem II level during salinity and irradiance stress. Plants were subjected for up to 13 days to either 0.4M NaCl salinity or high irradiance of 1000 micromol m(-2)s(-1), as well as to both stress factors combined (LLSA=low light plus salt; HLCO=high light of 1000 micromol m(-2)s(-1), no salt; HLSA=high light plus salt). A control of LLCO=low light of 200 micromol m(-2)s(-1), no salt was used. Parameters of chlorophyll a fluorescence of photosystem II (PSII) were measured with a pulse amplitude modulated fluorometer. HLCO and LLSA conditions induced a weak degree of CAM with day/night changes of malate levels (Deltamalate) of approximately 12mM in the course of the experiment, while HLSA induced stronger CAM of Deltamalate approximately 20 mM. Effective quantum yield of PSII, DeltaF/F'(m), was only slightly affected by LLSA, somewhat reduced during the course of the experiment by HLCO and clearly reduced by HLSA. Potential quantum efficiency of PSII, F(v)/F(m), at predawn times was not affected by any of the conditions, always remaining at 0.8, showing that there was no acute photoinhibition. During the course of the days HL alone (HLCO) also did not elicit photoinhibition; salt alone (LLSA) caused acute photoinhibition which was amplified by the combination of the two stresses (HLSA). Non-photochemical, NPQ, quenching remained low (crystallinum expresses effective stress tolerance mechanisms but photosynthetic capacity is reduced by the synergistic effects of salinity and light irradiance stress combined.

  16. An Introduction to Chlorophyll Fluorescence

    NARCIS (Netherlands)

    Harbinson, J.; Rosenqvist, E.

    2003-01-01

    Photosynthesis is a physiological process that couples the energy of light to certain metabolic changes in biochemical reactions, via photochemical processess. It is the purpose of this chapter to lay out the basic physical and physiological processess associated with this coupling and to show how

  17. Overview of remote sensing of chlorophyll flourescene in ocean waters

    African Journals Online (AJOL)

    This study reviews the history of initial cognitions, investigations and detailed approaches towards chlorophyll fluorescence, and then introduces the biological mechanism of fluorescence remote sensing and main spectral characteristics such as the positive correlation between fluorescence and chlorophyll concentration ...

  18. Potential of chlorophyll fluorescence and VIS/NIR spectroscopy measurement use for the detection of nitrogen content and disease infection of apple leaves

    Directory of Open Access Journals (Sweden)

    Václava Spáčilová

    2011-01-01

    Full Text Available A possibility of using spectral methods for determining a nutritional status and detecting pathogens in apple-tree cvs. ’Jonagold’ and ’Idared’ was verified in an orchard and pot experiments in 2007–2010. Treatments differed in the fertilizer or fungicide dose. Leaf samples were collected from the experimental variants to determine nitrogen content and to measure spectral reflectance (spectrophotometer Avantes USB 2000 and chlorophyll fluorescence imaging (FluorCam. Results of the measurements were correlated to leaf analyses for nitrogen content in dry matter. At the same time, a health status (the occurrence of fungal pathogens Venturia inaequalis and Podosphaera leucotricha was assessed and changes of photochemical efficiency of PSII of infected leaves were evaluated. The parameters providing the best description of differences in the photosynthetic activity of leaves depending on treatments (parameter Fv/Fm and parameter GENTY, known as ΦPSII – effective quantum yield of PSII were selected. The values of correlation coefficients of Fv/Fm and ΦPSII depending on fertilization treatments were as follows: Fv/Fm: r = −0.4735, p<0.000089, α = 0.05; ΦPSII: r = 0.755; p < 0.00038, α = 0.05. Data obtained from measuring with a spectrophotometer was used for the calculation to normalized difference vegetation indices NDVI; a significant relationship was found for the index GNDVI (r = 0.4691, p < 0,0002, α = 0.05. The significant difference between healthy leaves and leaves infected by the pathogens V. inaequalis and P. leucotricha was confirmed using the spectrophotometer, and the largest differences in reflectances were found in wavelengths around 400 nm. The values of indices GNDVI, RNDVI and NDVI 450 obtained from measuring reflectance of leaves with symptoms of V. inaequalis and P. leucotricha infections were significantly lower compared to the indices of healthy leaves. The values of indices NDVI were as follows: GNDVI 0

  19. Species-specific and seasonal differences in chlorophyll fluorescence and photosynthetic light response among three evergreen species in a Madrean sky island mixed conifer forest

    Science.gov (United States)

    Potts, D. L.; Minor, R. L.; Braun, Z.; Barron-Gafford, G. A.

    2012-12-01

    Unlike the snowmelt-dominated hydroclimate of more northern mountainous regions, the hydroclimate of the Madrean sky islands is characterized by snowmelt and convective storms associated with the North American Monsoon. These mid-summer storms trigger biological activity and are important drivers of primary productivity. For example, at the highest elevations where mixed conifer forests occur, ecosystem carbon balance is influenced by monsoon rains. Whereas these storms' significance is increasingly recognized at the ecosystem scale, species-specific physiological responses to the monsoon are poorly known. Prior to and following monsoon onset, we measured pre-dawn and light-adapted chlorophyll fluorescence as well as photosynthetic light response in southwestern white pine (Pinus strobiformis), ponderosa pine (Pinus ponderosa), and Douglas fir (Pseudotsuga menziesii) in a Madrean sky island mixed conifer forest near Tucson, Arizona. Photochemical quenching (qp), an indicator of the proportion of open PSII reaction centers, was greatest in P. strobiformis and least in P. menziesii and increased in response to monsoon rains (repeated-measures ANOVA; species, F2,14 = 6.17, P = 0.012; time, F2,14= 8.17, P = 0.013). In contrast, non-photochemical quenching (qN), an indicator of heat dissipation ability, was greatest in P. ponderosa and least in P. menziesii, but was not influenced by monsoon onset (repeated-measures ANOVA; species, F2,12 = 4.18, P = 0.042). Estimated from leaf area-adjusted photosynthetic light response curves, maximum photosynthetic rate (Amax) was greatest in P. ponderosa and least in P. menziesii (repeated-measures ANOVA; species, F2,8= 40.8, P = 0.001). Surprisingly, while the monsoon positively influenced Amax among P. ponderosa and P. strobiformis, Amax of P. menziesii declined with monsoon onset (repeated-measures ANOVA; species x time, F2,8 = 13.8, P = 0.002). Calculated as the initial slope of the photosynthetic light response curve, light

  20. The effects of UV radiation on photosynthesis estimated as chlorophyll fluorescence in Zygnemopsis decussata (Chlorophyta growing in a high mountain lake (Sierra Nevada, Southern Spain

    Directory of Open Access Journals (Sweden)

    Mayte MATA

    2009-08-01

    Full Text Available The effect of increased UV radiation on photosynthesis estimated as in vivo chlorophyll fluorescence i.e. optimal quantum yield (Fv/Fm and electron transport rate (ETR in the green filamentous alga Zygnemopsis decussata (Streptophyta, Zygnematales growing in the high mountain lake "La Caldera" (Sierra Nevada, Spain at 3050 m altitude was evaluated. Two sets of in situ experiments were conducted: (1 On July 2006, Fv/Fm was measured throughout the day at different depths (0.1, 0.25, 0.5 and 1 m and in the afternoon, ETR and phenolic compounds were determined. In addition, in order to analyze the effect of UV radiation, Fv/Fm was determined in algae incubated for 3 days at 0.5m under three different light treatments: PAR+UVA+UVB (PAB, PAR+UVA (PA and PAR (P. (2 On August 2007, Fv/Fm was determined under PAB, PA and P treatments and desiccation/rehydration conditions. Fv/Fm decreased in algae growing in surface waters (0.1 m but also at 1 m depth compared to that at 0.5 m depth. The decrease of Fv/Fm at noon due to photoinhibition was small (less than 10% except in algae growing at 1 m depth (44%. The maximal electron transport rate was 3.5-5 times higher in algae growing at 0.25-0.5 m respectively than that at 0.1 and 1 m depth. These results are related to the accumulation of phenolic compounds: i.e. the algae at 0.25-0.5 m presented respectively about a 3-5 times higher concentration of phenolic compounds than that of algae at 0.1-1 m depth. The protection mechanisms seem to be stimulated by UVB radiation, since Fv/Fm was higher in the presence of UVB (PAB treatment compared to PA or P treatments. UVA exerts the main photoinhibitory effect, not only at midday, but also in the afternoon. UVB radiation also had a protective effect in algae grown under desiccation conditions for three days. During re-hydration, the rapid increase of Fv/Fm (after 1 h was higher in the UVB-grown algae than in algae grown under UVA radiation. After 5 h, Fv/Fm values

  1. Fluorescência e teores de clorofilas em abacaxizeiro cv. pérola submetido a diferentes concentrações de sulfato de amônio Fluorescence and levels of chlorophyll in pineapple plants cv. perola submitted to different concentration of ammonium sulphate

    Directory of Open Access Journals (Sweden)

    Darlene Ana de Paula Vieira

    2010-06-01

    Full Text Available O presente trabalho teve como objetivo a análise da emissão da fluorescência da clorofila a e dos teores de clorofilas em plantas de Ananas comosus (L. Merril cv pérola, cultivadas em casa de vegetação, submetidas a quatro concentrações de nitrogênio por adição ou não de sulfato de amônio, de acordo com os seguintes tratamentos: Tº= 0 T1/2 = 15; T1 = 30; e T2 = 60 mg/kg solo. As determinações de fluorescência mínima (F0, máxima (Fm, variável (Fv, terminal (Ft e da eficiência fotoquímica máxima (Fv/Fm de folhas adaptadas ao escuro foram realizadas ao longo do dia, aos cinco dias após a segunda aplicação de sulfato de amônio, efetuada 120 dias após o transplantio. A adição de sulfato de amônio afetou a fluorescência variável e a máxima, mas não afetou a fluorescência mínima, a terminal nem a eficiência fotoquímica. Houve diferenças significativas entre os valores das variáveis da fluorescência ao longo do dia em que foram feitas as leituras. Houve diferenças nos teores de clorofilas foliares, em função das concentrações de sulfato de amônio aplicadas, com aumento para clorofila a e para a relação clorofila a/b, mas não para clorofila b.The present research aimed to analyze chlorophyll a fluorescence emission as well as chlorophyll levels in Ananas comosus (L. Merril cv Pérola grown under greenhouse conditions and submitted to four concentration of nitrogen, through addition or not of ammonium sulphate according to the following treatments: Tº= 0.000; T1/2 = 0.015; T1 =0.030; and T2 = 0.060 g/kg soil. Determinations of minimum (F0, maximum (Fm, variable (Fv, and terminal (Ft fluorescence and maximum photochemical efficiency (Fv/Fm of dark-adapted leaves were carried out during the day, five days after the second application of ammonium sulphate, carried out 120 days after the transplant. The results showed that the addition of ammonium sulphate affected variable and maximum fluorescence, but not

  2. FluorMODgui V3.0: A Graphic User Interface for the Spectral Simulation of Leaf and Canopy Chlorophyll Fluorescence

    OpenAIRE

    Zarco-Tejada, P. J.; Miller, J R; Pedrós Esteban, Roberto; Verhoef, W.; Berger, M.

    2006-01-01

    The FluorMODgui Graphic User Interface (GUI) software package developed within the frame of the FluorMOD project Development of a Vegetation Fluorescence Canopy Model is presented in this manuscript. The FluorMOD project was launched in 2002 by the European Space Agency (ESA) to advance the science of vegetation fluorescence simulation through the development and integration of leaf and canopy fluorescence models based on physical methods. The design of airborne or space missions dedicated to...

  3. Analysis of initial chlorophyll fluorescence induction kinetics in chloroplasts in terms of rate constants of donor side quenching release and electron trapping in photosystem II

    NARCIS (Netherlands)

    Vredenberg, W.J.

    2008-01-01

    The fluorescence induction F(t) of dark-adapted chloroplasts has been studied in multi-turnover 1 s light flashes (MTFs). A theoretical expression for the initial fluorescence rise is derived from a set of rate equations that describes the sequence of transfer steps associated with the reduction of

  4. Seedling quality tests: chlorophyll fluoresence

    Science.gov (United States)

    Gary Ritchie; Thomas D. Landis

    2005-01-01

    So far in this series we have discussed the most commonly -used seedling quality tests: root growth potential, cold hardiness, and stress resistance. In this issue, we're going to talk about one of the newest test-chlorophyll fluorescence (CF). The technology for measuring CF has been in place for over 50 years but has been applied to tr?e seedling physiology only...

  5. Comparison of a compatible and an incompatible pepper-tobamovirus interaction by biochemical and non-invasive techniques: chlorophyll a fluorescence, isothermal calorimetry and FT-Raman spectroscopy.

    Science.gov (United States)

    Rys, Magdalena; Juhász, Csilla; Surówka, Ewa; Janeczko, Anna; Saja, Diana; Tóbiás, István; Skoczowski, Andrzej; Barna, Balázs; Gullner, Gábor

    2014-10-01

    Leaves of a pepper cultivar harboring the L(3) resistance gene were inoculated with Obuda pepper virus (ObPV), which led to the appearance of hypersensitive necrotic lesions approx. 72 h post-inoculation (hpi) (incompatible interaction), or with Pepper mild mottle virus (PMMoV) that caused no visible symptoms on the inoculated leaves (compatible interaction). ObPV inoculation of leaves resulted in ion leakage already 18 hpi, up-regulation of a pepper carotenoid cleavage dioxygenase (CCD) gene from 24 hpi, heat emission and declining chlorophyll a content from 48 hpi, and partial desiccation from 72 hpi. After the appearance of necrotic lesions a strong inhibition of photochemical energy conversion was observed, which led to photochemically inactive leaf areas 96 hpi. However, leaf tissues adjacent to these inactive areas showed elevated ΦPSII and Fv/Fm values proving the advantage of chlorophyll a imaging technique. PMMoV inoculation also led to a significant rise of ion leakage and heat emission, to the up-regulation of the pepper CCD gene as well as to decreased PSII efficiency, but these responses were much weaker than in the case of ObPV inoculation. Chlorophyll b and total carotenoid contents as measured by spectrophotometric methods were not significantly influenced by any virus inoculations when these pigment contents were calculated on leaf surface basis. On the other hand, near-infrared FT-Raman spectroscopy showed an increase of carotenoid content in ObPV-inoculated leaves suggesting that the two techniques detect different sets of compounds. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  6. Spectral dependence of irreversible light-induced fluorescence quenching: Chlorophyll forms with maximal emission at 700-702 and 705-710nm as spectroscopic markers of conformational changes in the core complex.

    Science.gov (United States)

    Nematov, Sherzod; Casazza, Anna Paola; Remelli, William; Khuvondikov, Vakhobjon; Santabarbara, Stefano

    2017-07-01

    The spectral dependence of the irreversible non-photochemical fluorescence quenching associated with photoinhibition in vitro has been comparatively investigated in thylakoid membranes, PSII enriched particles and PSII core complexes isolated from spinach. The analysis of the fluorescence emission spectra of dark-adapted and quenched samples as a function of the detection temperature in the 280-80K interval, indicates that Chlorophyll spectral forms having maximal emission in the 700-702nm and 705-710nm ranges gain relative intensity in concomitance with the establishment of irreversible light-induced quenching, acting thereby as spectroscopic markers. The relative enhancement of the 700-702nm and 705-710nm forms emission could be due either to an increase of their stoichiometric abundance or to their intrinsically low fluorescence quantum yields. These two factors, that can also coexist, need to be promoted by light-induced alterations in chromophore-protein as well as chromophore-chromophore interactions. The bands centred at about 701 and 706nm are also observed in the PSII core complex, suggesting their, at least partial, localisation in proximity to the reaction centre, and the occurrence of light-induced conformational changes in the core subunits. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Effects of phosphorus on the growth and chlorophyll fluorescence of a Dunaliella salina strain isolated from saline soil under nitrate limitation

    Directory of Open Access Journals (Sweden)

    Tassnapa Wongsnansilp

    2016-12-01

    Full Text Available An isolated Dunaliella salina (D. salina KU XI from saline soils in northeastern Thailand was cultured in f/2 medium in column photobioreactor. The variations of the growth, chlorophyll and beta-carotene content and the maximum quantum yield of PS II photochemistry (Fv/Fm under different NaH2PO4 concentrations were studied. Based on the results, the growth kinetics of D. salina KU XI was established, which could simulate the algae growth rate under different phosphate concentrations and temperatures. The phosphorus could significantly affect the growth and pigments accumulations of this isolated strain. Increasing NaH2PO4 concentration improved the biomass, the total chlorophyll and beta-carotene content, retarded the decrease of Fv/Fm value. The optimal phosphate concentration for the growth of D. salina KU XI was above 72.6 μM. The maximum biomass and beta-carotene were 0.24 g L-1 and 17.4 mg L-1 respectively when NaH2PO4 was 290.4 μM. The algae growth was restrained by phosphate or nitrate when NaH2PO4 below 12.1 μM or above 72.6 μM. It indicated that properly supplementing nitrate in the late growth stage with high phosphate concentration was favored for enhancing the growth and biomass production.

  8. Changes in photosynthetic properties measured by oxygen evolution and variable chlorophyll fluorescence in a simulated entrainment experiment with the cyanobacterium Planktothrix rubescens

    NARCIS (Netherlands)

    Kromkamp, J.C.; Domin, A.; Dubinsky, Z.; Lehmann, C.; Schanz, F.

    2001-01-01

    The metalimnion of lake Zurich is dominated by the red coloured cyanobacterium Planktotrix rubescens, where it lives in an extremely low light environment. Photosynthesis of the organism was studied using oxygen evolution and variable fluorescence. After transfer to 2 in depth in the epilimnion.

  9. Kinetic models of photosystem II should accommodate the effect of donor side quenching on variable chlorophyll a fluorescence in the microseconds time

    NARCIS (Netherlands)

    Vredenberg, W.J.

    2009-01-01

    Quantitative data on laser flash-induced variable fluorescence in the 100 ns to 1 ms time range (Belyaeva et al. in Photosynth Res 98:105–119, 2008) confirming those of others (Steffen et al. in Biochemistry 40:173–180, 2001, Biochemistry 44:3123–3132, 2005; Belyaeva et al. in Biophysics

  10. Chlorophylls - natural solar cells

    CERN Document Server

    Jantschi, Lorentz; Balan, Mugur C; Sestras, Radu E

    2011-01-01

    A molecular modeling study was conducted on a series of six natural occurring chlorophylls. Quantum chemistry calculated orbital energies were used to estimate frequency of transitions between occupied molecular orbital and unoccupied molecular orbital energy levels of chlorophyll molecules in vivo conditions in standard (ASTMG173) environmental conditions. Obtained results are in good agreement with energies necessary to fix the Magnesium atom by chlorophyll molecules and with occurrence of chlorophylls in living vegetal organisms.

  11. Effect of chelating agents and metal ions on nickel bioavailability and chlorophyll fluorescence response in wheat- An approach for attenuation of Ni stress

    Directory of Open Access Journals (Sweden)

    Nilima Patnaik

    2012-08-01

    Full Text Available The objectives of the study are to analyze the physiological changes, biochemical alterations and attenuation of nickel toxicity effects in wheat seedlings under combined applications of Ni ions, metal chelators (EDTA/Citric Acid and metal ions (Zn2+ /Mg2+. Wheat (Triticum aestivum L cv UP262 seedlings were grown hydroponically using different concentrations of Ni up to 7 days along with chelators and metal ions for study. The seedling growth was maximum with NiCl2–Zn2+ (100μM and minimum with NiCl2–EDTA (100μM treatments. Total chlorophyll content was maximum in the seedlings treated with NiCl2-Zn2+ (100μM and minimum in NiCl2-EDTA (100μM treatments. NiCl2–EDTA (100μM showed less Fo and Fm values and therefore, a trend in the decrease in OJIP transient indicates the maximum alteration of photochemical activity of PS-II in presence of NiCl2–EDTA (100μM treatment. Similar observation was found by NiCl2 –EDTA (200μM treatment where Fo and Fm values were noted to decline. High nickel content in roots of the seedlings was noted as compared to shoots.

  12. Differential response of radish plants to supplemental ultraviolet-B radiation under varying NPK levels: chlorophyll fluorescence, gas exchange and antioxidants.

    Science.gov (United States)

    Singh, Suruchi; Kumari, Rima; Agrawal, Madhoolika; Agrawal, Shashi Bhushan

    2012-07-01

    Current and projected increases in ultraviolet-B (UV-B; 280-315 nm) radiation may alter crop growth and yield by modifying the physiological and biochemical functions. This study was conducted to assess the possibility of alleviating the negative effects of supplemental UV-B (sUV-B; 7.2 kJ m⁻² day⁻¹; 280-315 nm) on radish (Raphanus sativus var Pusa Himani) by modifying soil nitrogen (N), phosphorus (P) and potassium (K) levels. The N, P and K treatments were recommended dose of N, P and K, 1.5 times recommended dose of N, P and K, 1.5 times recommended dose of N and 1.5 times recommended dose of K. Plants showed variations in their response to UV-B radiation under varying soil NPK levels. The minimum damaging effects of sUV-B on photosynthesis rate and stomatal conductance coupled with minimum reduction in chlorophyll content were recorded for plants grown at recommended dose of NPK. Flavonoids increased under sUV-B except in plants grown at 1.5 times recommended dose of N. Lipid peroxidation (LPO) also increased in response to sUV-B at all NPK levels with maximum at 1.5 times recommended dose of K and minimum at recommended dose of NPK. This study revealed that sUV-B radiation negatively affected the radish plants by reducing the photosynthetic efficiency and increasing LPO. The plants grown at 1.5 times recommended dose of NPK/N/K could not enhance antioxidative potential to the extent as recorded at recommended dose of NPK and hence showed more sensitivity to sUV-B. Copyright © Physiologia Plantarum 2012.

  13. Estimating Chlorophyll Fluorescence Parameters Using the Joint Fraunhofer Line Depth and Laser-Induced Saturation Pulse (FLD-LISP Method in Different Plant Species

    Directory of Open Access Journals (Sweden)

    Parinaz Rahimzadeh-Bajgiran

    2017-06-01

    Full Text Available A comprehensive evaluation of the recently developed Fraunhofer line depth (FLD and laser-induced saturation pulse (FLD-LISP method was conducted to measure chlorophyll fluorescence (ChlF parameters of the quantum yield of photosystem II (ΦPSII, non-photochemical quenching (NPQ, and the photosystem II-based electron transport rate (ETR in three plant species including paprika (C3 plant, maize (C4 plant, and pachira (C3 plant. First, the relationships between photosynthetic photon flux density (PPFD and ChlF parameters retrieved using FLD-LISP and the pulse amplitude-modulated (PAM methods were analyzed for all three species. Then the relationships between ChlF parameters measured using FLD-LISP and PAM were evaluated for the plants in different growth stages of leaves from mature to aging conditions. The relationships of ChlF parameters/PPFD were similar in both FLD-LISP and PAM methods in all plant species. ΦPSII showed a linear relationship with PPFD in all three species whereas NPQ was found to be linearly related to PPFD in paprika and maize, but not for pachira. The ETR/PPFD relationship was nonlinear with increasing values observed for PPFDs lower than about 800 μmol m−2 s−1 for paprika, lower than about 1200 μmol m−2 s−1 for maize, and lower than about 800 μmol m−2 s−1 for pachira. The ΦPSII, NPQ, and ETR of both the FLD-LISP and PAM methods were very well correlated (R2 = 0.89, RMSE = 0.05, (R2 = 0.86, RMSE = 0.44, and (R2 = 0.88, RMSE = 24.69, respectively, for all plants. Therefore, the FLD-LISP method can be recommended as a robust technique for the estimation of ChlF parameters.

  14. Systems approach to excitation-energy and electron transfer reaction networks in photosystem II complex: model studies for chlorophyll a fluorescence induction kinetics.

    Science.gov (United States)

    Matsuoka, Takeshi; Tanaka, Shigenori; Ebina, Kuniyoshi

    2015-09-07

    Photosystem II (PS II) is a protein complex which evolves oxygen and drives charge separation for photosynthesis employing electron and excitation-energy transfer processes over a wide timescale range from picoseconds to milliseconds. While the fluorescence emitted by the antenna pigments of this complex is known as an important indicator of the activity of photosynthesis, its interpretation was difficult because of the complexity of PS II. In this study, an extensive kinetic model which describes the complex and multi-timescale characteristics of PS II is analyzed through the use of the hierarchical coarse-graining method proposed in the authors׳ earlier work. In this coarse-grained analysis, the reaction center (RC) is described by two states, open and closed RCs, both of which consist of oxidized and neutral special pairs being in quasi-equilibrium states. Besides, the PS II model at millisecond scale with three-state RC, which was studied previously, could be derived by suitably adjusting the kinetic parameters of electron transfer between tyrosine and RC. Our novel coarse-grained model of PS II can appropriately explain the light-intensity dependent change of the characteristic patterns of fluorescence induction kinetics from O-J-I-P, which shows two inflection points, J and I, between initial point O and peak point P, to O-J-D-I-P, which shows a dip D between J and I inflection points. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Chlorophyll in tomato seeds: marker for seed performance?

    NARCIS (Netherlands)

    Suhartanto, M.R.

    2002-01-01

    Using Xe-PAM, laser induced fluorometry and high performance liquid chromatography we found that chlorophyll was present in young tomato (cv. Moneymaker) seeds and was degraded during maturation. Fluorescence microscopy and imaging showed that the majority of chlorophyll is located in the

  16. Chlorophyll alpha fluorescence analysis along a vertical gradient of the crown in a poplar (Oxford clone) subjected to ozone and water stress.

    Science.gov (United States)

    Desotgiu, Rosanna; Pollastrini, Martina; Cascio, Chiara; Gerosa, Giacomo; Marzuoli, Riccardo; Bussotti, Filippo

    2012-08-01

    An experiment in open-top chambers was carried out in summer 2008 at Curno (Northern Italy) in order to study the effects of ozone and mild water stress on poplar cuttings (Oxford clone). In this experiment direct fluorescence parameters (JIP-test) were measured in leaves from different sections of the crown (L: lower; M: medium; U: upper parts of the crown). The parameters considered were calculated at the different steps of the fluorescence transient, and include maximum quantum yield efficiency in the dark-adapted state (F(v)/F(M)); the L-band, at 100 ∝ s, that expresses the stability of the tripartite system reaction centre-harvesting light complex-core antenna; the K-band, at 300 ∝ s, that expresses the efficiency of the oxygen-evolving complex; the J-phase, at 2 ms, that expresses the efficiency with which a trapped exciton can move an electron into the electron transport chain from Q(A)(-) to the intersystem electron acceptors; the IP-phase, which expresses the efficiency of electron transport around the photosystem 1 (PSI) to reduce the final acceptors of the electron transport chain, i.e., ferredoxin and NADP; and finally the performance index total (PItot) for energy conservation from photons absorbed by PSII to the reduction flux of PSI end acceptors. The main results are: (i) different dynamics were observed between leaves in the lower section, whose PItot decreased over time, and those in the upper sections in which it increased, with a dynamic connected to the leaf age; (ii) ozone depressed all the considered fluorescence parameters in basal leaves of well-watered plants, while it had little or no damaging effect on medium-level or upper-section leaves; (iii) PItot and IP-phase increased in upper leaves of plants subjected to ozone stress, as well as the net photosynthesis; (iv) water stress increased PItot of leaves in all levels of the crown. The results suggest that ozone-damaged poplar plants compensate, at least partially, for the

  17. Endolithic chlorophyll d-containing phototrophs

    DEFF Research Database (Denmark)

    Behrendt, Lars; Larkum, Anthony W D; Norman, Anders

    2011-01-01

    hyperspectral and variable chlorophyll fluorescence imaging, scanning electron microscopy, photopigment analysis and DNA sequencing to show that Acaryochloris-like cyanobacteria thrive underneath crustose coralline algae in a widespread endolithic habitat on coral reefs. This finding suggests an important role...

  18. In vitro complexes of copper and zinc with chlorophyll

    Directory of Open Access Journals (Sweden)

    JELENA PETROVIC

    2006-05-01

    Full Text Available Complexes of copper and zinc with chlorophyll, the major photosynthesis pigment, were studied by Vis, FTIR and fluorescence spectroscopy. Two types of complexes were recognized. While copper replaces the central magnesium atom of chlorophyll to form a “central” Cu–Chl complex, this was not proposed in the case of zinc. Instead, the zinc-mediated formation of a 6-membered chelate cycle fused at the periphery of the chlorophyll structure is proposed. The latter event could be ascribed to allomerization reactions of chlorophyll.

  19. Chlorophyll and starch assays

    OpenAIRE

    sprotocols

    2015-01-01

    Chlorophyll, starch, and sugar contents are good indicators of growth vigor in plants. To measure the chlorophyll content, we used a modified protocol (1,2). The starch content was determined using iodine staining (3) and enzymatic reactions (4-6).

  20. Detection of upward and downward Solar-induced chlorophyll fluorescence emissions at the forest floor in a cool-temperate deciduous broadleaf forest in Japan

    Science.gov (United States)

    Kato, T.; Tsujimoto, K.; Nasahara, K. N.; Akitsu, T.; Murayama, S.; Noda, H.; Muraoka, H.

    2016-12-01

    Strong representation of Sun-Induced Fluorescence (SIF) for the ecosystem-level photosynthesis activity has been confirmed by satellite studies [Frankenberg et al., 2011; Joiner et al., 2013] and by field studies [Porcar-Castell, 2011, Yang et al., 2015]. However, the lack of taking care of SIF emission below the tree canopy top may underestimate the contribution of sub-canopy and the understory species to total ecosystem CO2dynamics. To examine the potential contribution of SIF emission from lower part of tree ecosystem to total ecosystem SIF emission, the downward SIF from tree canopy and upward SIF from understory were calculated from the spectrum data in a cool temperate forest in in central Japan (36°08'N, 137°25'E, 1420 masl) as well as the upward SIF from canopy top, and the fractional ratios among them are compared on half-hourly and daily bases from 2006 to 2007. The top canopy is dominated by Oak and Birches, and the sub-canopy layer and shrub layers are dominated by Acer, Hydrangea and Viburnum species. The understory is dominated by an evergreen dwarf bamboo Sasa senanensis, and covered partially by the seedlings of oak and maple, and herbaceous species [Muraoka and Koizumi, 2005]. The SIF was estimated from the spectrums of downward and upward irradiances measured at two heights of 18m and 2m above ground by HemiSpherical Spectro-Radiometer, consisting of the spectroradiometer (MS700, Eko inc., Tokyo, Japan) with the FWHM of 10 nm and wavelength interval of 3.3 nm. The SIF around 760nm (O2-A band) was calculated according to the Fraunhofer Line Depth principle with additional arrangements. Our preliminary results show that the SIF emission intensity was kept in the order as canopy upward > canopy downward > understory upward for most of growing season, except for short spring time between snow melt and canopy greening because of the evergreen Sasa bamboo grass at the forest floor. On the other hand, the relative intensities among three SIF emissions

  1. Survival

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data provide information on the survival of California red-legged frogs in a unique ecosystem to better conserve this threatened species while restoring...

  2. OSU Chlorophyll Bloom Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This product was developed for the Oregon coast based on the observed change between running 8-day composite chlorophyll-a (CHL) data obtained by the MODerate...

  3. Chlorophyll: The wonder pigment

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.R.

    Benefits Chlorophyll has been used in folk medicine as a deodorizer. It is effective for those suffering from halitosis (bad breath) and can be used for a freshening gargle. It is used in treating diabetic foot ulcer, constipation and hemorrhoids...

  4. Chlorophyll_Master

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set included chlorophyll for each subregion in the study (Georges Bank, Gulf of Maine, Southern New England, Middle Atlantic Bight) . The data came from...

  5. Daily Changes in CO2 and Water Vapor Exchange, Chlorophyll Fluorescence, and Leaf Water Relations in the Halophyte Mesembryanthemum crystallinum during the Induction of Crassulacean Acid Metabolism in Response to High NaCl Salinity 1

    Science.gov (United States)

    Winter, Klaus; Gademann, Rolf

    1991-01-01

    Simultaneous measurements of net CO2 exchange, water vapor exchange, and leaf water relations were performed in Mesembryanthemum crystallinum during the development of crassulacean acid metabolism (CAM) in response to high NaCl salinity in the rooting medium. Determinations of chlorophyll a fluorescence were used to estimate relative changes in electron transport rate. Alterations in leaf mass per unit area, which—on a short-term basis—largely reflect changes in water content, were recorded continuously with a beta-gauge. Turgor pressure of mesophyll cells was determined with a pressure probe. As reported previously (K Winter, DJ von Willert [1972] Z Pflanzenphysiol 67: 166-170), recently expanded leaves of plants grown under nonsaline conditions showed gas-exchange characteristics of a C3 plant. Although these plants were not exposed to any particular stress treatment, water content and turgor pressure regularly decreased toward the end of the 12 hour light periods and recovered during the following 12 hours of darkness. When the NaCl concentration of the rooting medium was raised to 400 millimolar, in increments of 100 millimolar given at the onset of the photoperiods for 4 consecutive days, leaf water content and turgor pressure decreased by as much as 30 and 60%, respectively, during the course of the photoperiods. These transient decreases probably triggered the induction of the biochemical machinery which is required for CAM to operate. After several days at 400 millimolar NaCl, when leaves showed features typical of CAM, overall turgor pressure and leaf mass per unit area had increased above the levels before onset of the salt treatment, and diurnal alterations in leaf water content were reduced. Net carbon gain during photoperiods and average intercellular CO2 partial pressures at which net CO2 uptake occurred, progressively decreased upon salinization. Reversible diurnal depressions in leaf conductance and net CO2 uptake, with minima recorded in the

  6. Chlorophyll formation and phytochrome

    NARCIS (Netherlands)

    Raven, C.W.

    1973-01-01

    The rôle of phytochrome in the regeneration of protochlorophyll (Pchl) in darkness following short exposures to light, as well as in the accumulation of chlorophyll- a (Chl- a ) in continuous light in previously dark-grown seedlings of pea, bean,

  7. Pulse amplitude modulated chlorophyll fluorometer

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, Elias; Wu, Jie

    2015-12-29

    Chlorophyll fluorometry may be used for detecting toxins in a sample because of changes in micro algae. A portable lab on a chip ("LOAC") based chlorophyll fluorometer may be used for toxin detection and environmental monitoring. In particular, the system may include a microfluidic pulse amplitude modulated ("PAM") chlorophyll fluorometer. The LOAC PAM chlorophyll fluorometer may analyze microalgae and cyanobacteria that grow naturally in source drinking water.

  8. Spatial and temporal variability of chlorophyll in Bay of Bengal.

    Science.gov (United States)

    Jutla, A.; Akanda, S.; Islam, S.

    2009-04-01

    The Bay of Bengal (BoB) receives approximately 628 km3/ year of freshwater discharge from the Ganges and Brahmaputra rivers. Freshwater discharge from rivers increases the nutrient load and thereby enhances phytoplankton production in the BoB. Cholera, an infectious water-borne disease caused by bacterium Vibrio cholerae, remains endemic in the BoB region. Phytoplankton provides favorable environment for survival of cholera bacteria. Therefore, for development of any predictive model for cholera, it is important to quantify the spatial and temporal variability of phytoplankton in the BoB. Satellite remote sensing is the most effective way to quantify this variability over a range of space and time scales. Using ten years (1998-2007) of daily, weekly and monthly SeaWiFs chlorophyll, a surrogate variable for measuring phytoplankton, imagery we explore the spatial pattern and dominant temporal variability of chlorophyll over the BoB region. We find that chlorophyll in the coastal waters has more variability, both in temporal and spatial scales, than the offshore waters. Mechanism of production and space-time variability of coastal chlorophyll is different from those of offshore chlorophyll. While coastal chlorophyll is dominated by influx of terrestrial nutrients through river discharge, chlorophyll in the offshore region is primarily controlled by oceanic processes. We will also explore issues related to dominant space and time scales of chlorophyll variations in the entire bay.

  9. Chloroplastid pigment contents and chlorophyll a fluorescence in Amazonian tropical three species Concentração de pigmentos cloroplastídicos e fluorescência da clorofila a em espécies arbóreas tropicais da Amazônia

    Directory of Open Access Journals (Sweden)

    Ronaldo Ribeiro de Morais

    2007-10-01

    Full Text Available Plants react to changes in light and hydrological conditions in terms of quantity and composition of chloroplastidic pigments, which affects the photosynthetic properties and consequently the accumulation of plant biomass. Thus, the chloroplastidic pigment concentration and chlorophyll a fluorescence of three Amazonian species (Bertholletia excelsa, Carapa guianensis e Dipteryx odorata were investigated in sun and shade leaves form the tree crown collected during two distinct periods of precipitation (dry and rainy seasons. Pigment contents were determined by spectrophotometry and fluorescence variables were determined using a portable fluorometer. The results demonstrated that the species showed high concentrations of Chl a, Chl b e Chl total during the wet season in relation to the dry season, especially in shade leaves. A higher concentration of carotenoids was found in B. excelsa, when compared with leaves of C. guianensis and D. odorata. In leaves of B. excelsa and D. odorata no significant difference was found in relation to the photochemistry of photosystem II (Fv/Fm between the wet and dry seasons. In conclusion, the three species react differently to variations in the light and precipitation conditions regarding light capture, aspects that might be considered in the management of forest plantations.As plantas respondem a mudanças nas condições de luz e na disponibilidade hídrica em termos da quantidade e composição dos pigmentos cloroplastídicos, o que afeta as propriedades fotossintéticas e, conseqüentemente, o acúmulo de biomassa das espécies. Assim, a concentração de pigmentos cloroplastídicos e a fluorescência da clorofila a de três espécies arbóreas (Bertholletia excelsa, Carapa guianensis e Dipteryx odorata da Amazônia foi investigada em folhas sombreadas e não-sombreadas da copa das árvores e em dois períodos distintos de precipitação (chuvoso e seco. As concentrações de pigmentos foram determinadas por

  10. Laser-Induced Breakdown Spectroscopy and Chlorophyll a Flourescence Transients

    DEFF Research Database (Denmark)

    Frydenvang, Jens

    of a sufficient quality; something that remains a problem for many in-situ methods. In my PhD, I present my work with two such in-situ methods, Laser-Induced Breakdown Spectroscopy (LIBS) and OJIP transients, the rising part of chlorophyll a fluorescence transients from dark-adapted leaves....

  11. A novel chlorophyll solar cell

    Science.gov (United States)

    Ludlow, J. C.

    The photosynthetic process is reviewed in order to produce a design for a chlorophyll solar cell. In a leaf, antenna chlorophyll absorbs light energy and conducts it to an energy trap composed of a protein and two chlorophyll molecules, which perform the oxidation-reduction chemistry. The redox potential of the trap changes from 0.4 to -0.6 V, which is sufficient to reduce nearby molecules with redox potentials in that range. The reduction occurs by transfer of an electron, and a chlorophyll solar cell would direct the transferred electron to a current carrier. Chlorophyll antenna and traps are placed on a metallic support immersed in an electron acceptor solution, and resulting electrons from exposure to light are gathered by a metallic current collector. Spinach chlorophyll extracted, purified, and applied in a cell featuring a Pt collector and an octane water emulsion resulted in intensity independent voltages.

  12. Fluorescence-guided surgery of retroperitoneal-implanted human fibrosarcoma in nude mice delays or eliminates tumor recurrence and increases survival compared to bright-light surgery.

    Science.gov (United States)

    Uehara, Fuminari; Hiroshima, Yukihiko; Miwa, Shinji; Tome, Yasunori; Yano, Shuya; Yamamoto, Mako; Matsumoto, Yasunori; Maehara, Hiroki; Tanaka, Kazuhiro; Bouvet, Michael; Kanaya, Fuminori; Hoffman, Robert M

    2015-01-01

    The aim of this study is to determine if fluorescence-guided surgery (FGS) can eradicate human fibrosarcoma growing in the retroperitoneum of nude mice. One week after retroperitoneal implantation of human HT1080 fibrosarcoma cells, expressing green fluorescent protein (GFP) (HT-1080-GFP), in nude mice, bright-light surgery (BLS) was performed on all tumor-bearing mice (n = 22). After BLS, mice were randomized into 2 treatment groups; BLS-only (n = 11) or the combination of BLS + FGS (n = 11). The residual tumors remaining after BLS were resected with FGS using a hand-held portable imaging system under fluorescence navigation. The average residual tumor area after BLS + FGS was significantly smaller than after BLS-only (0.4 ± 0.4 mm(2) and 10.5 ± 2.4 mm(2), respectively; p = 0.006). Five weeks after surgery, the fluorescent-tumor areas of BLS- and BLS + FGS-treated mice were 379 ± 147 mm(2) and 11.7 ± 6.9 mm(2), respectively, indicating that FGS greatly inhibited tumor recurrence compared to BLS. The combination of BLS + FGS significantly decreased fibrosarcoma recurrence compared to BLS-only treated mice (p fibrosarcoma volume after BLS and improved disease-free survival.

  13. Fluorescence-guided surgery of retroperitoneal-implanted human fibrosarcoma in nude mice delays or eliminates tumor recurrence and increases survival compared to bright-light surgery.

    Directory of Open Access Journals (Sweden)

    Fuminari Uehara

    Full Text Available The aim of this study is to determine if fluorescence-guided surgery (FGS can eradicate human fibrosarcoma growing in the retroperitoneum of nude mice. One week after retroperitoneal implantation of human HT1080 fibrosarcoma cells, expressing green fluorescent protein (GFP (HT-1080-GFP, in nude mice, bright-light surgery (BLS was performed on all tumor-bearing mice (n = 22. After BLS, mice were randomized into 2 treatment groups; BLS-only (n = 11 or the combination of BLS + FGS (n = 11. The residual tumors remaining after BLS were resected with FGS using a hand-held portable imaging system under fluorescence navigation. The average residual tumor area after BLS + FGS was significantly smaller than after BLS-only (0.4 ± 0.4 mm(2 and 10.5 ± 2.4 mm(2, respectively; p = 0.006. Five weeks after surgery, the fluorescent-tumor areas of BLS- and BLS + FGS-treated mice were 379 ± 147 mm(2 and 11.7 ± 6.9 mm(2, respectively, indicating that FGS greatly inhibited tumor recurrence compared to BLS. The combination of BLS + FGS significantly decreased fibrosarcoma recurrence compared to BLS-only treated mice (p < 0.001. Mice treated with BLS+FGS had a significantly higher disease-free survival rate than mice treated with BLS-only at five weeks after surgery. These results suggest that combination of BLS + FGS significantly reduced the residual fibrosarcoma volume after BLS and improved disease-free survival.

  14. Chlorophyll d: the puzzle resolved

    DEFF Research Database (Denmark)

    Larkum, Anthony W D; Kühl, Michael

    2005-01-01

    Chlorophyll a (Chl a) has always been regarded as the sole chlorophyll with a role in photochemical conversion in oxygen-evolving phototrophs, whereas chlorophyll d (Chl d), discovered in small quantities in red algae in 1943, was often regarded as an artefact of isolation. Now, as a result...... of discoveries over the past year, it has become clear that Chl d is the major chlorophyll of a free-living and widely distributed cyanobacterium that lives in light environments depleted in visible light and enhanced in infrared radiation. Moreover, Chl d not only has a light-harvesting role but might also...... replace Chl a in the special pair of chlorophylls in both reactions centers of photosynthesis. Udgivelsesdato: 2005-Aug...

  15. Quantification of plant chlorophyll content using Google Glass.

    Science.gov (United States)

    Cortazar, Bingen; Koydemir, Hatice Ceylan; Tseng, Derek; Feng, Steve; Ozcan, Aydogan

    2015-04-07

    Measuring plant chlorophyll concentration is a well-known and commonly used method in agriculture and environmental applications for monitoring plant health, which also correlates with many other plant parameters including, e.g., carotenoids, nitrogen, maximum green fluorescence, etc. Direct chlorophyll measurement using chemical extraction is destructive, complex and time-consuming, which has led to the development of mobile optical readers, providing non-destructive but at the same time relatively expensive tools for evaluation of plant chlorophyll levels. Here we demonstrate accurate measurement of chlorophyll concentration in plant leaves using Google Glass and a custom-developed software application together with a cost-effective leaf holder and multi-spectral illuminator device. Two images, taken using Google Glass, of a leaf placed in our portable illuminator device under red and white (i.e., broadband) light-emitting-diode (LED) illumination are uploaded to our servers for remote digital processing and chlorophyll quantification, with results returned to the user in less than 10 seconds. Intensity measurements extracted from the uploaded images are mapped against gold-standard colorimetric measurements made through a commercially available reader to generate calibration curves for plant leaf chlorophyll concentration. Using five plant species to calibrate our system, we demonstrate that our approach can accurately and rapidly estimate chlorophyll concentration of fifteen different plant species under both indoor and outdoor lighting conditions. This Google Glass based chlorophyll measurement platform can display the results in spatiotemporal and tabular forms and would be highly useful for monitoring of plant health in environmental and agriculture related applications, including e.g., urban plant monitoring, indirect measurements of the effects of climate change, and as an early indicator for water, soil, and air quality degradation.

  16. Análise dos transientes da fluorescência da clorofila a de plantas jovens de Carapa guianensis e de Dipteryx odorata submetidas a dois ambientes de luz Analysis of chlorophyll a fluorescence transients of young plants of Carapa guianensis and Dipteryx odorata submitted to two light environments

    Directory of Open Access Journals (Sweden)

    José Francisco de Carvalho Gonçalves

    2010-03-01

    odorata (Aublet Willd exposed to two light environments (shade and sunlight. The experiment was carried in Manaus-AM, Brazil (3º8'S, 59º52'W. Analysis of chlorophyll a fluorescence transients were obtained in intact and healthy leaves between 10:00 to 12:00 am. The curve OJIP indicated that the species high irradiance exposed presented photoinhibition after 45 days of experiment. Andiroba and cumaru plants exposed to sunlight exhibited low values of TRo/ABS (7.17 and 20.4%, respectively, ETo/TRo (14.5 and 27.2%, respectively and ETo/ABS (20.6 and 42.2%, respectively and high values of DIo/ABS (26.9 and 43.0%, respectively, compared with plants exposed to the shadow with 45 days of experiment. As for phenomenological flux, most of the parameters, low values were observed for both exposed species in the sunlight. Andiroba and cumaru plants exposed in the sunlight exhibited low values of PIABS (63.3 and 78.7%, respectively compared with exposed plants to the shadow at the end of the experiment. Although the species have suffered with the stress for high irradiance andiroba specie presented better performance than cumaru being indicated for use in production planting or degraded area restoration.

  17. Structures of chlorophyll catabolites in bananas (Musa acuminata) reveal a split path of chlorophyll breakdown in a ripening fruit.

    Science.gov (United States)

    Moser, Simone; Müller, Thomas; Holzinger, Andreas; Lütz, Cornelius; Kräutler, Bernhard

    2012-08-27

    The disappearance of chlorophyll is a visual sign of fruit ripening. Yet, chlorophyll breakdown in fruit has hardly been explored; its non-green degradation products are largely unknown. Here we report the analysis and structure elucidation of colorless tetrapyrrolic chlorophyll breakdown products in commercially available, ripening bananas (Musa acuminata, Cavendish cultivar). In banana peels, chlorophyll catabolites were found in an unprecedented structural richness: a variety of new fluorescent chlorophyll catabolites (FCCs) and nonfluorescent chlorophyll catabolites (NCCs) were detected. As a rule, FCCs exist only "fleetingly" and are hard to observe. However, in bananas several of the FCCs (named Mc-FCCs) were persistent and carried an ester function at the propionate side-chain. NCCs were less abundant, and exhibited a free propionic acid group, but functional modifications elsewhere. The modifications of NCCs in banana peels were similar to those found in NCCs from senescent leaves. They are presumed to be introduced by enzymatic transformations at the stage of the mostly unobserved, direct FCC-precursors. The observed divergent functional group characteristics of the Mc-FCCs versus those of the Mc-NCCs indicated two major "late" processing lines of chlorophyll breakdown in ripening bananas. The "last common precursor" at the branching point to either the persistent FCCs, or towards the NCCs, was identified as a temporarily abundant "secondary" FCC. The existence of two "downstream" branches of chlorophyll breakdown in banana peels, and the striking accumulation of persistent Mc-FCCs call for attention as to the still-elusive biological roles of the resulting colorless linear tetrapyrroles. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Chlorophyll breakdown in senescent Arabidopsis leaves. Characterization of chlorophyll catabolites and of chlorophyll catabolic enzymes involved in the degreening reaction.

    Science.gov (United States)

    Pruzinská, Adriana; Tanner, Gaby; Aubry, Sylvain; Anders, Iwona; Moser, Simone; Müller, Thomas; Ongania, Karl-Hans; Kräutler, Bernhard; Youn, Ji-Young; Liljegren, Sarah J; Hörtensteiner, Stefan

    2005-09-01

    During senescence, chlorophyll (chl) is metabolized to colorless nonfluorescent chl catabolites (NCCs). A central reaction of the breakdown pathway is the ring cleavage of pheophorbide (pheide) a to a primary fluorescent chl catabolite. Two enzymes catalyze this reaction, pheide a oxygenase (PAO) and red chl catabolite reductase. Five NCCs and three fluorescent chl catabolites (FCCs) accumulated during dark-induced chl breakdown in Arabidopsis (Arabidopsis thaliana). Three of these NCCs and one FCC (primary fluorescent chl catabolite-1) were identical to known catabolites from canola (Brassica napus). The presence in Arabidopsis of two modified FCCs supports the hypothesis that modifications, as present in NCCs, occur at the level of FCC. Chl degradation in Arabidopsis correlated with the accumulation of FCCs and NCCs, as well as with an increase in PAO activity. This increase was due to an up-regulation of Pao gene expression. In contrast, red chl catabolite reductase is not regulated during leaf development and senescence. A pao1 knockout mutant was identified and analyzed. The mutant showed an age- and light-dependent cell death phenotype on leaves and in flowers caused by the accumulation of photoreactive pheide a. In the dark, pao1 exhibited a stay-green phenotype. The key role of PAO in chl breakdown is discussed.

  19. New fluorescence parameters for monitoring photosynthesis in plants

    NARCIS (Netherlands)

    Force, L.; Critchley, Ch.; Rensen, van J.J.S.

    2003-01-01

    Chlorophyll fluorescence measurements have a wide range of applications from basic understanding of photosynthesis functioning to plant environmental stress responses and direct assessments of plant health. The measured signal is the fluorescence intensity (expressed in relative units) and the most

  20. STAY-GREEN and chlorophyll catabolic enzymes interact at light-harvesting complex II for chlorophyll detoxification during leaf senescence in Arabidopsis.

    Science.gov (United States)

    Sakuraba, Yasuhito; Schelbert, Silvia; Park, So-Yon; Han, Su-Hyun; Lee, Byoung-Doo; Andrès, Céline Besagni; Kessler, Felix; Hörtensteiner, Stefan; Paek, Nam-Chon

    2012-02-01

    During leaf senescence, plants degrade chlorophyll to colorless linear tetrapyrroles that are stored in the vacuole of senescing cells. The early steps of chlorophyll breakdown occur in plastids. To date, five chlorophyll catabolic enzymes (CCEs), NONYELLOW COLORING1 (NYC1), NYC1-LIKE, pheophytinase, pheophorbide a oxygenase (PAO), and red chlorophyll catabolite reductase, have been identified; these enzymes catalyze the stepwise degradation of chlorophyll to a fluorescent intermediate, pFCC, which is then exported from the plastid. In addition, STAY-GREEN (SGR), Mendel's green cotyledon gene encoding a chloroplast protein, is required for the initiation of chlorophyll breakdown in plastids. Senescence-induced SGR binds to light-harvesting complex II (LHCII), but its exact role remains elusive. Here, we show that all five CCEs also specifically interact with LHCII. In addition, SGR and CCEs interact directly or indirectly with each other at LHCII, and SGR is essential for recruiting CCEs in senescing chloroplasts. PAO, which had been attributed to the inner envelope, is found to localize in the thylakoid membrane. These data indicate a predominant role for the SGR-CCE-LHCII protein interaction in the breakdown of LHCII-located chlorophyll, likely to allow metabolic channeling of phototoxic chlorophyll breakdown intermediates upstream of nontoxic pFCC.

  1. Fluorescent dissolved organic matter in the continental shelf waters ...

    Indian Academy of Sciences (India)

    Although chlorophyll is less in this (southern) region, the fluorescence based biological index (BIX) which is an index of recent phytoplankton production is about the same in the two regions, and the lower chlorophyll of southern region is attributed to greater grazing pressure. Fluorescence properties, e.g., BIX are more ...

  2. High-performance liquid chromatographic screening of chlorophyll derivatives produced during fruit storage.

    Science.gov (United States)

    Almela, L; Fernández-López, J A; Roca, M J

    2000-02-18

    Reversed-phase high-performance liquid chromatography with photodiode array and fluorescence detection was applied to the systematic screening of chlorophylls and derivative pigments. The chromatographic procedure proposed made it possible to successfully separate and identify eight chlorophyll derivatives (the a and b forms of chlorophyll, chlorophyllide, pheophytin and pheophorbide) by using a linear gradient of methanol, acetone and ammonium acetate. The method has been routinely applied to study chlorophyll degradation during the postharvest storage of cherimoya (Annona cherimola, Mill.) fruits. The brilliant green colour even at maturity, and its high chlorophyllase and Mg-dechelating activities, indicate that this plant material might be suitable for investigating the as yet not well known chlorophyll breakdown processes.

  3. Photosynthetic bark : use of chlorophyll absorption continuum index to estimate Boswellia papyrifera bark chlorophyll content

    NARCIS (Netherlands)

    Girma Gebrekidan, A.; Skidmore, A.K.; de Bie, C.A.J.M.; Bongers, Frans; Schlerf, Martin; Schlerf, M.

    2013-01-01

    Quantification of chlorophyll content provides useful insight into the physiological performance of plants. Several leaf chlorophyll estimation techniques, using hyperspectral instruments, are available. However, to our knowledge, a non-destructive bark chlorophyll estimation technique is not

  4. Photosynthetic bark: use of chlorophyll absorption continuum index to estimate Boswellia papyrifera bark chlorophyll content

    NARCIS (Netherlands)

    Girma, A.; Skidmore, A.K.; Bie, de C.A.J.M.; Bongers, F.; Schlerf, M.

    2013-01-01

    Quantification of chlorophyll content provides useful insight into the physiological performance of plants. Several leaf chlorophyll estimation techniques, using hyperspectral instruments, are available. However, to our knowledge, a non-destructive bark chlorophyll estimation technique is not

  5. [Investigation of exciting light and plant leaves age effects on chlorophyll fluorescense of radish plants].

    Science.gov (United States)

    Nesterenko, T V; Tikhomirov, A A; Shikhov, V N

    2012-01-01

    The effect of exciting light intensity and leaves age on characteristics of slow stage of chlorophyll fluorescence induction (CFI) of radish leaves has been investigated. Light dependence of the relationship of maximum fluorescence intensity in the peak P and the stationary fluorescence level (F(P)/F(S)) and also light dependence of temporal characteristics of CFI (T0.5 - half decrease of chlorophyll fluorescence intensity during slow stage of fluorescence induction and tmin - summarized CFI characteristics derived by calculating via integral proportional to variable part of illuminated in the result of chlorophyll fluorescence energy during slow stage of CFI) have been studied. Plants were grown in controlled conditions of light culture at 100 Wt/m2 of photosynthetic active radiation (PAR). It has been shown that variability of the characteristics under study, associated with the effect of leaves age, significantly decreases at exciting light intensity equal to 40 Wt/m2 of PAR and more. The lowest effect of leaves age on the value of fluorescence characteristics for T0.5 and tmin and also for F(P)/F(S) ratio was observed at the intensity of exciting fluorescence light of 60 Wt/m2 of PAR. In the researched range of light intensities the temporal characteristics of T0.5 and tmin for uneven-aged radish leaves appeared to be by an order less responsive to the intensity changes of exciting fluorescence light as compared with F(P)/F(S) ratio.

  6. Investigating the Control of Chlorophyll Degradation by Genomic Correlation Mining.

    Directory of Open Access Journals (Sweden)

    Frederick P Ghandchi

    Full Text Available Chlorophyll degradation is an intricate process that is critical in a variety of plant tissues at different times during the plant life cycle. Many of the photoactive chlorophyll degradation intermediates are exceptionally cytotoxic necessitating that the pathway be carefully coordinated and regulated. The primary regulatory step in the chlorophyll degradation pathway involves the enzyme pheophorbide a oxygenase (PAO, which oxidizes the chlorophyll intermediate pheophorbide a, that is eventually converted to non-fluorescent chlorophyll catabolites. There is evidence that PAO is differentially regulated across different environmental and developmental conditions with both transcriptional and post-transcriptional components, but the involved regulatory elements are uncertain or unknown. We hypothesized that transcription factors modulate PAO expression across different environmental conditions, such as cold and drought, as well as during developmental transitions to leaf senescence and maturation of green seeds. To test these hypotheses, several sets of Arabidopsis genomic and bioinformatic experiments were investigated and re-analyzed using computational approaches. PAO expression was compared across varied environmental conditions in the three separate datasets using regression modeling and correlation mining to identify gene elements co-expressed with PAO. Their functions were investigated as candidate upstream transcription factors or other regulatory elements that may regulate PAO expression. PAO transcript expression was found to be significantly up-regulated in warm conditions, during leaf senescence, and in drought conditions, and in all three conditions significantly positively correlated with expression of transcription factor Arabidopsis thaliana activating factor 1 (ATAF1, suggesting that ATAF1 is triggered in the plant response to these processes or abiotic stresses and in result up-regulates PAO expression. The proposed regulatory

  7. The Total Synthesis of Chlorophyll

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 7. The Total Synthesis of Chlorophyll. Setty Mallikarjuna Babu Subramania Ranganathan. General Article Volume 19 Issue 7 July 2014 pp 645-648. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. The Total Synthesis of Chlorophyll

    Indian Academy of Sciences (India)

    IAS Admin

    ecule was transformed and rent asunder in innumerable directions, and the fascination and intricacy of the chemistry of chlorophyll and its congeners was fully revealed. These massive contributions were crowned by the proposal, in. 1940 of a structure which was complete except for stereochemical detail. – R B Woodward ...

  9. Chlorophylls, Symmetry, Chirality, and Photosynthesis

    Directory of Open Access Journals (Sweden)

    Mathias O. Senge

    2014-09-01

    Full Text Available Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full potential in solar energy conversion by working in concert in highly complex, supramolecular structures such as the reaction centers and light-harvesting complexes of photobiology. The biochemical function of these structures depends on the controlled interplay of structural and functional principles of the apoprotein and pigment cofactors. Chlorophylls and bacteriochlorophylls are optically active molecules with several chiral centers, which are necessary for their natural biological function and the assembly of their supramolecular complexes. However, in many cases the exact role of chromophore stereochemistry in the biological context is unknown. This review gives an overview of chlorophyll research in terms of basic function, biosynthesis and their functional and structural role in photosynthesis. It highlights aspects of chirality and symmetry of chlorophylls to elicit further interest in their role in nature.

  10. Chlorophylls, Symmetry, Chirality, and Photosynthesis.

    OpenAIRE

    Senge, Mathias O.; Aoife A. Ryan; Kristie A. Letchford; MacGowan, Stuart A.; Tamara Mielke

    2014-01-01

    PUBLISHED Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full potential in solar energy conversion by working in concert in highly complex, supramolecula...

  11. Complexes and aggregates of chlorophylls

    NARCIS (Netherlands)

    Kooyman, R.P.H.

    1980-01-01

    Chlorophyll (Chl) molecules can form complexes in two important ways: by ligation at the magnesium atom and/or by hydrogen bonding at the keto- carbonyl group. Under certain conditions these processes may give rise to dimer formation. This thesis describes some properties of complexes and dimers of

  12. Effects of acute O3 stress on PSII and PSI photochemistry of sensitive and resistant snap bean genotypes (Phaseolus vulgaris L.), probed by prompt chlorophyll "a" fluorescence and 820 nm modulated reflectance.

    Science.gov (United States)

    Salvatori, Elisabetta; Fusaro, Lina; Strasser, Reto J; Bussotti, Filippo; Manes, Fausto

    2015-12-01

    The response of PSII and PSI photochemistry to acute ozone (O3) stress was tested in a "model plant system", namely the O3 sensitive (S156) and O3 resistant (R123) genotype pairs of Phaseolus vulgaris L., during a phenological phase of higher O3 sensitivity (pod formation). The modulation of the photosynthetic activity during O3 stress was analysed by measuring gas exchanges, Prompt Fluorescence (PF, JIP-test) and 820 nm Modulated Reflectance (MR), a novel techniques which specifically detects the changes in the redox state of P700 and plastocyanin. The results showed that, coherently with genotypic-specific O3 sensitivity, the response of the two snap bean genotypes differed for the intensity and time of onset of the considered physiological changes. In fact, despite leaf injury and gas exchanges reduction appeared concurrently in both genotypes, S156 showed a PSII down regulation already after the first day of fumigation (DOF), and an enhancement of Cyclic Electron Flow of PSI after the second DOF, whereas R123 showed only slight adjustments until the third DOF, when the activity of both photosystems was down-regulated. Despite these differences, it is possible to distinguish in both genotypes an early O3 response of the photochemical apparatus, involving PSII only, and a following response, in which PSI activity and content are also modulated. The measurement of the MR signal, performed simultaneously with the PF measurements and the JIP-test analysis, has allowed a better understanding of the role that PSI plays in the O3 stress response of the S156/R123 model plant system. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  13. Survival rate of wine-related yeasts during alcoholic fermentation assessed by direct live/dead staining combined with fluorescence in situ hybridization.

    Science.gov (United States)

    Branco, Patrícia; Monteiro, Margarida; Moura, Patrícia; Albergaria, Helena

    2012-08-01

    Real-time detection of microorganisms involved in complex microbial process, such as wine fermentations, and evaluation of their physiological state is crucial to predict whether or not those microbial species will be able to impact the final product. In the present work we used a direct live/dead staining (LDS) procedure combined with fluorescence in situ hybridization (FISH) to simultaneously assess the identity and viability of Saccharomyces cerevisiae (Sc) and Hanseniaspora guilliermondii (Hg) during fermentations performed with single and mixed cultures. The population evolution of both yeasts was determined by plating and by LDS combined with species-specific FISH-probes labeled with Fluorescein. Since the FISH method involves the permeabilization of the cell membrane prior to hybridization and that it may influence the free diffusion of PI in and out of the cells, we optimized the concentration of this dye (0.5 μg of PI per 10(6) cells) for minimal diffusion (less than 2%). Fluorescent cells were enumerated by hemocytometry and flow cytometry. Results showed that the survival rate of Sc during mixed cultures was high throughout the entire process (60% of viable cells at the 9th day), while Hg began to die off at the 2nd day, exhibited 98% of dead cells at the 3rd day (45 g/l of ethanol) and became completely unculturable at the 4th day. However, under single culture fermentation the survival rate and culturability of Hg decreased at a much slower pace, exhibiting at the 7th day (67 g/l of ethanol) 8.7×10(4) CFU/ml and 85% of dead cells. Thus, our work demonstrated that the LDS-FISH method is able to simultaneously assess the viability and identity of these wine-related yeast species during alcoholic fermentation in a fast and reliable way. In order to validate PI-staining as a viability marker during alcoholic fermentation, we evaluated the effect of ethanol on the membrane permeability of Sc and Hg cells, as well as their capacity to recover membrane

  14. Isolation of chlorophyll a from spinach leaves

    Directory of Open Access Journals (Sweden)

    E.D. Dikio

    2008-08-01

    Full Text Available An efficient method for separating chlorophyll a from spinach leaves by column chromatography and solvent extraction techniques has been developed. The purity and identity of the chlorophyll a have been confirmed by UV-Vis, IR and mass spectrometry. Yields from 100 g of freeze-dried spinach were 23 – 24 mg of chlorophyll a.

  15. Relationship between chlorophyll density and SPAD chlorophyll meter reading for Jerusalem artichoke (Helianthus tuberosus L.)

    Science.gov (United States)

    Chlorophyll is an indicator of crop health and productivity. Measuring chlorophyll is usually done directly and requires significant time and resources. Indirect measurement of chlorophyll density using a handheld portable chlorophyll meter can reduce time. However, this information is very limit...

  16. Delayed fluorescence in photosynthesis.

    Science.gov (United States)

    Goltsev, Vasilij; Zaharieva, Ivelina; Chernev, Petko; Strasser, Reto J

    2009-01-01

    Photosynthesis is a very efficient photochemical process. Nevertheless, plants emit some of the absorbed energy as light quanta. This luminescence is emitted, predominantly, by excited chlorophyll a molecules in the light-harvesting antenna, associated with Photosystem II (PS II) reaction centers. The emission that occurs before the utilization of the excitation energy in the primary photochemical reaction is called prompt fluorescence. Light emission can also be observed from repopulated excited chlorophylls as a result of recombination of the charge pairs. In this case, some time-dependent redox reactions occur before the excitation of the chlorophyll. This delays the light emission and provides the name for this phenomenon-delayed fluorescence (DF), or delayed light emission (DLE). The DF intensity is a decreasing polyphasic function of the time after illumination, which reflects the kinetics of electron transport reactions both on the (electron) donor and the (electron) acceptor sides of PS II. Two main experimental approaches are used for DF measurements: (a) recording of the DF decay in the dark after a single turnover flash or after continuous light excitation and (b) recording of the DF intensity during light adaptation of the photosynthesizing samples (induction curves), following a period of darkness. In this paper we review historical data on DF research and recent advances in the understanding of the relation between the delayed fluorescence and specific reactions in PS II. An experimental method for simultaneous recording of the induction transients of prompt and delayed chlorophyll fluorescence and decay curves of DF in the millisecond time domain is discussed.

  17. Energy transfer from carotenoids to chlorophyll in blue-green, red and green algae and greening bean leaves

    NARCIS (Netherlands)

    Goedheer, J.C.

    1969-01-01

    From fluorescence action spectra, fluorescence spectra and absorption spectra measured at room temperature and at 77 °K of light petroleum (b.p. 40–60°)-treated and normal chloroplasts, it is concluded that: 1. 1. In blue-green and red algae energy transfer from β-carotene to chlorophyll occurs

  18. Obsolete - AFSC/RACE/Eco-FOCI: Chlorophyll: groundtruth data for chlorophyll fluorescence sensors on the moorings.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are part of a ocean observation study by Stabeno, Napp, and Whitledge sponsored, in part, but the North Pacific Research Board (Project 410;...

  19. Chlorophyll a fluorescence to phenotype wheat genotypes for heat tolerance

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto

    for 72h was appropriate to induce genotype dependent variation in Fv/Fm. This standardized protocol was used to phenotype wheat genotypes until the variation in the genotypes was consistently high with increased heritability for the trait, Fv/Fm. Mass screening of 1273 wheat genotypes in a milder stress...

  20. Chlorophyll a fluorescence to phenotype wheat genotypes for heat tolerance

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto

    Wheat (Triticum aestivum L.) is a heat-susceptible crop throughout its phenological stages, flowering phase being the most sensitive stage. Early stress detection method with advanced physiological measurements may provide new dimensions to establish a high throughput phenotyping technique....... Initial phenotyping of 1300 wheat genotypes in a milder stress at 38oC for 2 h showed a heritability of 7% for Fv/Fm. However, a stronger stress at 40oC for 72 h in repeated experiments on 138 extreme performing lines resulted in a genotype dependent drop in Fv/Fm and an increased genetic component of 15...

  1. Physiotypic Plasticity and Survival of Arido-active Euphorbia triaculeata (Euphorbiaceae in its Natural Habitat

    Directory of Open Access Journals (Sweden)

    Turki A. Al-Turki

    2014-12-01

    Full Text Available Leafless stem succulent Euphorbia triaculeata Forssk. is abundant in arid regions southwest of the Arabian Peninsula. These regions are characterized by short wet season with erratic rainfall and long dry season with high temperature and high irradiance. Field observations indicated that the plant survives the long dry season and acquires a red stem colour under high irradiance and protracted drought. Our work aimed at investigating survival of this arido-active species in its natural habitat by studying diurnal and seasonal changes in stomatal conductance, cell sap acidity, and chlorophyll fluorescence. Results showed that E. triaculeata is obligate crassulacean acid metabolism (CAM plant. Under protracted drought, low stomatal conductance and dampening of CAM denoted a shift to CAM-idling. Observed stress-induced reduction of Photosystem II activity occurred in concomitance with increased non-photochemical quenching of chlorophyll fluorescence and increased anthocyanin content. These results reflected operation of a photoprotective mechanism involving interplay of non-photochemical energy dissipation via xanthophyll cycle and alleviation of oxidative stress by anthocyanin. It was concluded that E. triaculeata survives in its arid habitat by performing obligate CAM, shifting to CAM-idling under protracted drought, increasing non-photochemical excess energy dissipation, and accumulating anthocyanin pigment for its antioxidant attributes.

  2. Fluorescence, Aqua MODIS, NPP, 0.125 degrees, West US

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS measures chlorophyll fluorescence, which gives insight into the physiology of phytoplankton in the ocean. When phytoplankton are under stress, the rate at...

  3. Fluorescence, Aqua MODIS, NPP, 0.125 degrees, East US

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS measures chlorophyll fluorescence, which gives insight into the physiology of phytoplankton in the ocean. When phytoplankton are under stress, the rate at...

  4. The spontaneous chlorophyll mutation frequency in barley

    DEFF Research Database (Denmark)

    Jørgensen, Jørgen Helms; Jensen, Hans Peter

    1986-01-01

    materials and the resulting estimate of the chlorophyll mutant frequency is 1.6 .times. 10-4 in about 1.43 million seedlings. The estimate of the chlorophyll mutation rate per generation is close to 67.3 .times. 10-4 per diploid genome or in the order of 6 .times. 10-7 per locus and haploid genome....

  5. Portable plant chlorophyll fluorimeter based on blue LED rapid induced technology

    Science.gov (United States)

    Zheng, Yibo; Mi, Ting; Zhang, Lei; Zhao, Jun

    2018-01-01

    Fluorimeter is an effective device for detecting chlorophyll a content in plants. In order to realize real-time nondestructive detection of plant blades, a camera based fluorescence instrument based on two color mirrors has been developed. The blue light LED is used as the excitation light source, and the lens is used for shaping and focusing the excitation light to ensure the excitation intensity and uniform illumination of the light source. The device uses a 45 degree two color mirror to separate the chlorophyll a excited light path and the fluorescence receiving light path. Finally, the fluorescent signal is collected by the silicon photocell, and the signal is processed by the circuit to transmit the digital information to the display. Through the analysis of the experimental data, the device has the advantages of small size, easy to carry, fast induction, etc., and can be widely applied in outdoor teaching and field investigation.

  6. Fluorescence Properties of Chlorella sp. Algae

    Directory of Open Access Journals (Sweden)

    Tibor Teplicky

    2017-01-01

    Full Text Available Water quality and its fast and reliable monitoring is the challenge of the future. Design of appropriate biosensors that would be capable of non-invasive identification of water pollution is an important prerequisite for such challenge. Chlorophylls are pigments, naturally presented in all plants that absorb light. The main forms of chlorophyll in algae are chlorophyll a and chlorophyll b, other pigments include xantophylls and beta-carotenes. Our aim was to characterize endogenous fluorescence of the Chlorella sp. algae, present naturally in drinking water. We recorded spatial, spectral and lifetime fluorescence distribution in the native algae. We noted that the fluorescence was evenly distributed in the algae cytosol, but lacked in the nucleus and reached maximum at 680-690 nm. Fluorescence decay of chlorella sp. was double-exponential, and clearly shorter than that of its isolated pigments. For the first time, fluorescence lifetime image of the algae is presented. Study of the fluorescence properties of algae is aimed at the improvement of water supply contamination detection and cleaning.

  7. Quantifying mangrove chlorophyll from high spatial resolution imagery

    NARCIS (Netherlands)

    Heenkenda, M.K.; Joyce, K.E.; Maier, S.W.; Bruin, de S.

    2015-01-01

    Lower than expected chlorophyll concentration of a plant can directly limit photosynthetic activity, and resultant primary production. Low chlorophyll concentration may also indicate plant physiological stress. Compared to other terrestrial vegetation, mangrove chlorophyll variations are poorly

  8. Chlorophyll Breakdown in Senescent Arabidopsis Leaves. Characterization of Chlorophyll Catabolites and of Chlorophyll Catabolic Enzymes Involved in the Degreening Reaction1

    Science.gov (United States)

    Pružinská, Adriana; Tanner, Gaby; Aubry, Sylvain; Anders, Iwona; Moser, Simone; Müller, Thomas; Ongania, Karl-Hans; Kräutler, Bernhard; Youn, Ji-Young; Liljegren, Sarah J.; Hörtensteiner, Stefan

    2005-01-01

    During senescence, chlorophyll (chl) is metabolized to colorless nonfluorescent chl catabolites (NCCs). A central reaction of the breakdown pathway is the ring cleavage of pheophorbide (pheide) a to a primary fluorescent chl catabolite. Two enzymes catalyze this reaction, pheide a oxygenase (PAO) and red chl catabolite reductase. Five NCCs and three fluorescent chl catabolites (FCCs) accumulated during dark-induced chl breakdown in Arabidopsis (Arabidopsis thaliana). Three of these NCCs and one FCC (primary fluorescent chl catabolite-1) were identical to known catabolites from canola (Brassica napus). The presence in Arabidopsis of two modified FCCs supports the hypothesis that modifications, as present in NCCs, occur at the level of FCC. Chl degradation in Arabidopsis correlated with the accumulation of FCCs and NCCs, as well as with an increase in PAO activity. This increase was due to an up-regulation of Pao gene expression. In contrast, red chl catabolite reductase is not regulated during leaf development and senescence. A pao1 knockout mutant was identified and analyzed. The mutant showed an age- and light-dependent cell death phenotype on leaves and in flowers caused by the accumulation of photoreactive pheide a. In the dark, pao1 exhibited a stay-green phenotype. The key role of PAO in chl breakdown is discussed. PMID:16113212

  9. Mediterranean Ocean Colour Chlorophyll trend

    Science.gov (United States)

    rinaldi, eleonora; colella, simone; santoleri, rosalia

    2014-05-01

    Monitoring chlorophyll (Chl) concentration, seen as a proxy for phytoplankton biomass, is an efficient tool in order to understand the response of marine ecosystem to human pressures. This is particularly important along the coastal regions, in which the strong anthropization and the irrational exploitation of resources represent a persistent threat to the biodiversity. The aim of this work is to assess the effectiveness and feasibility of using Ocean Color (OC) data to monitor the environmental changes in Mediterranean Sea and to develop a method for detecting trend from OC data that can constitute a new indicator of the water quality within the EU Marine Strategy Framework Directive implementation. In this study the Mediterranean merged Case1-Case2 chlorophyll product, produced by CNR-ISAC and distributed in the framework of MyOcean, is analyzed. This product is obtained by using two different bio-optical algorithms for open ocean (Case1) and coastal turbid (Case2) waters; this improves the quality of the Chl satellite estimates, especially near the coast. In order to verify the real capability of the this product for estimating Chl trend and for selecting the most appropriated statistical test to detect trend in the Mediterranean Sea, a comparison between OC and in situ data are carried out. In-situ Chl data are part of the European Environment Information and Observation Network (Eionet) of the European Environmental Agency (EEA). Four different statistical approaches to estimate trend have been selected and used to compare trend values obtained with in-situ and OC data. Results show that the best agreement between in-situ and OC trend is achieved using the Mann- Kendall test. The Mediterranean trend map obtained applying this test to the de-seasonalized OC time series shows that, in accordance with the results of many authors, the case 1 waters of Mediterranean sea are characterized by a negative trend. However, the most intense trend signals, both negative

  10. Optimization and effects of different culture conditions on growth of Halomicronema hongdechloris – a filamentous cyanobacterium containing chlorophyll f

    Directory of Open Access Journals (Sweden)

    Yaqiong eLi

    2014-02-01

    Full Text Available A chlorophyll f containing cyanobacterium, Halomicronema hongdechloris (H. hongdechloris was isolated from a stromatolite cyanobacterial community. However, the extremely slower growth rate of H. hongdechloris culture became a critical factor, hindering the research on this newly isolated cyanobacterium and the investigation of chlorophyll f-photosynthesis. Therefore, optimizing H. hongdechloris culture conditions has become an essential requirement for future research. This work investigated the effects of various culture conditions, essential nutrients and light environments to determine the optimal growth conditions for H. hongdechloris and the biosynthetic rate of chlorophyll f. Based on the total chlorophyll concentration, an optimal growth rate of 0.22 ± 0.02 day-1 (doubling time: 3.1 ± 0.3 days was observed when cells were grown under continuous illumination with far-red light with an intensity of 20 µE at 32°C in modified K+ES seawater (pH 8.0 with additional supplements of 11.75 mM NaNO3 and 0.15 mM K2HPO4. High performance liquid chromatography on H. hongdechloris pigments confirmed that chlorophyll a is the major chlorophyll and chlorophyll f constitutes approximately 10% of the total chlorophyll from cells grown under far-red light. Fluorescence confocal image analysis demonstrated changes of photosynthetic membranes and the distribution of photopigments in response to different light conditions. The total photosynthetic oxygen evolution yield per cell showed no changes under different light conditions, which confirms the involvement of chlorophyll f in oxygenic photosynthesis. The implications of the presence of chlorophyll f in H. hongdechloris and its relationship to light environment are discussed.

  11. Localisation of chlorophyll within the chloroplast

    NARCIS (Netherlands)

    Thomas, J.B.; Post, L.C.; Vertregt, N.

    1954-01-01

    Silver nitrate reduction was shown to occur in illuminated suspensions of Hibiscus grana. The action spectrum of this reduction, the reaction, proved to coincide satisfactorily with the chlorophyll absorption spectrum. Electron micrographs reveal that this reaction occurs in single lamellae.

  12. Monthly Composite Chlorophyll Concentrations - Gulf of Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are monthly composites, and were calculated...

  13. EmpiricalValues_Chlorophyll_GrandComposite

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are a composite of several years (1997-2005)...

  14. Seasonal Composite Chlorophyll Concentrations - Gulf of Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are seasonal composites, and were calculated...

  15. Mediterranean Ocean Colour Chlorophyll Trends.

    Directory of Open Access Journals (Sweden)

    Simone Colella

    Full Text Available In being at the base of the marine food web, phytoplankton is particularly important for marine ecosystem functioning (e.g., biodiversity. Strong anthropization, over-exploitation of natural resources, and climate change affect the natural amount of phytoplankton and, therefore, represent a continuous threat to the biodiversity in marine waters. In particular, a concerning risks for coastal waters is the increase in nutrient inputs of terrestrial/anthropogenic origin that can lead to undesirable modifications of phytoplankton concentration (i.e., eutrophication. Monitoring chlorophyll (Chl concentration, which is a proxy of phytoplankton biomass, is an efficient tool for recording and understanding the response of the marine ecosystem to human pressures and thus for detecting eutrophication. Here, we compute Chl trends over the Mediterranean Sea by using satellite data, also highlighting the fact that remote sensing may represent an efficient and reliable solution to synoptically control the "good environmental status" (i.e., the Marine Directive to achieve Good Environmental Status of EU marine waters by 2020 and to assess the application of international regulations and environmental directives. Our methodology includes the use of an ad hoc regional (i.e., Mediterranean algorithm for Chl concentration retrieval, also accounting for the difference between offshore (i.e., Case I and coastal (i.e., Case II waters. We apply the Mann-Kendall test and the Sens's method for trend estimation to the Chl concentration de-seasonalized monthly time series, as obtained from the X-11 technique. We also provide a preliminary analysis of some particular trends by evaluating their associated inter-annual variability. The high spatial resolution of our approach allows a clear identification of intense trends in those coastal waters that are affected by river outflows. We do not attempt to attribute the observed trends to specific anthropogenic events. However

  16. CHANGES IN CHLOROPHYLL A FLOURESCENCE AND PIGMENT RATIOS DURING DIFFERENT GROWTH PHASES OF A UNICELLULAR MARINE CHAETOCEROS (BACILLAROPHYCEAE) IN BATCH CULTURE

    Science.gov (United States)

    Interpretations of chlorophyll a fluorescence data are based largely on application with green algae and higher plants. This study evaluated the interpretation of fluorescence data for a unicellular marine diatom. Chaetoceros sp. was grown in 4-liter batch cultures on a 16:8, L:D...

  17. Meridional and seasonal variations in the satellite-sensed fraction of euphotic zone chlorophyll

    Science.gov (United States)

    Strass, Volker H.

    1990-10-01

    The key to estimating ocean primary production from satellite color images is to project accurately the total euphotic zone chlorophyll content from the remotely sensed signal, emitted from merely the near-surface reaches. In situ profiles of chlorophyll fluorescence and solar irradiance (and temperature), collected at different times of the phytoplankton growth season with a towed undulator along a section running from the Azores toward Greenland, are used for simulating satellite measurements. Given by the simulations, the satellite-sensed fraction of the euphotic zone chlorophyll content accounts for only 7.5% on average, and it varies meridionally and seasonally by several times of its mean value. The major variations are attributed to changes in the chlorophyll vertical distribution, which are related to the succession of growth phases during the phytoplankton seasonal cycle: the onset of the spring bloom, the development of the bloom to full spate, and the transition to oligotrophy. To improve satellite-based estimates of integral euphotic zone chlorophyll quantities, it is suggested that use be made of the sea surface temperature field as a predictor of the time-dependent meridional transitions between the different growth phases.

  18. Evaluation of the MERIS terrestrial Chlorophyll Index

    Science.gov (United States)

    Dash, J.; Curran, P.

    The MEdium Resolution Imaging Spectrometer (MERIS), one of the payloads on Envisat, has fine spectral resolution, moderate spatial resolution and a three day repeat cycle. This makes MERIS a potentially valuable sensor for the measurement and monitoring of terrestrial environments at regional to global scales. The red edge, which results from an abrupt change in reflectance in red and near-infrared wavelengths has a location that is related directly to the chlorophyll content of vegetation. A new index called the MERIS terrestrial chlorophyll index (MTCI) uses data in three red and NIR wavebands centred at 681.25nm, 705nm and 753.75nm (bands 8, 9 and 10 in the MERIS standard band setting). The MTCI is easy to calculate and can be automated. Preliminary indirect evaluation using model, field and MERIS data suggested its sensitivity, notably to high values of chlorophyll content and its limited sensitivity to spatial resolution and atmospheric effects. As a result this index is now a standard level-2 product of the European Space Agency. For direct MTCI evaluation two different approaches were used. First, the MTCI/chlorophyll content relationship were determined using a surrogate of chlorophyll content for sites in southern Vietnam and second, the MTCI/chlorophyll relationship was determined using actual chlorophyll content for sites in the New Forest, UK and for plots in a greenhouse. Forests in southern Vietnam were contaminated heavily with Agent Orange during the Vietnam War. The contamination levels were so high that it led to a long term decrease in chlorophyll content within forests that have long since regained full canopy cover. In this approach the amount of Agent Orange dropped onto the forest between 1965 and 1971 was used as a surrogate for contemporary chlorophyll content and was related to current MTCI at selected forest sites. The resulting relationship was positive. Further per pixel investigation of the MTCI/Agent Orange concentration relationship

  19. In situ Analysis of Coral Recruits Using Fluorescence Imaging

    Directory of Open Access Journals (Sweden)

    Adi Zweifler

    2017-09-01

    Full Text Available Recruitment is a fundamental process that influences coral population dynamics as well as reef community structure. To date, coral recruitment success rates are poorly quantified because survey methods are labor-intensive and require manual interpretation. Thus, they are prone to human errors and have low repeatability—a gap we aim to bridge in this research. Since both corals and their symbiotic algae contain fluorescent pigments (chlorophyll and fluorescent proteins, we used the non-invasive Fluorescence Imaging System (FluorIS and developed a methodology to acquire daytime fluorescent photographs and identify coral recruits in them. We tested our method by monitoring 20 random quadrats at two sites in the Gulf of Aqaba, Israel. The quadrats were surveyed once a month for 8 months in order to track the settlement, mortality and survival rates of new coral recruits. We demonstrate daytime imaging using our method and identification of coral recruits as small as 1 mm in diameter, in a 20 × 20 cm quadrat. Our results show that this photographic method reduces surveyor errors and improves precision. The surveys revealed that on average, there are ~2 new coral recruit settlements (<2 cm for a quadrat (40 cm2 per month and that 83% of them survive the first month. Our study suggests a relative stability in the Gulf of Aqaba coral population during the survey period. The ability to survey recruits during the day using low-cost, easy-to-use photographic equipment has the potential to contribute significantly to the standardization of coral reef monitoring and management tools, at a time when the world's coral reefs are declining due to local and global stressors.

  20. Crassulacean Acid Metabolism Permutation and Survival of Caralluma Species (Apocynaceae in Arid Habitats

    Directory of Open Access Journals (Sweden)

    Yahya S. Masrahi

    2012-07-01

    Full Text Available Several species of the stem succulent Caralluma (Apocynaceae are abundant perennials in arid regions of the Arabian Peninsula. These arid regions have a short wet season with erratic rainfall and are characterized by harsh climatic conditions of high temperature, high evaporation and sand storms. Work presented in this paper aimed at investigating importance of Crassulacean Acid Metabolism (CAM for survival of three Caralluma species in their natural habitat. Investigations involved studying stomatal characteristics, stomatal diffusive conductance, chlorophyll fluorescence, and CAM in three species of Caralluma, namely C. acutangula (Decne. N.E.Br., C. edulis (Edgew. Benth. ex Hook.f., and C. subulata (Forssk. Decne. Microscopic examination revealed a pattern of stomatal characteristics typical of CAM plants in these three Caralluma species. Results showed that these three Caralluma species were obligate CAM plants exhibiting this mode of photosynthesis during both the wet and the dry seasons. Under protracted water stress during the long dry season very low values of stomatal diffusive conductance and dampening of CAM acidification-deacidification cycles denoted the tendency of these three Caralluma species to shift from the obligate CAM physiotype to CAM-idling mode. Chlorophyll fluorescence measurements indicated that protracted water stress induced a reduction in Photosystem II (PSII antenna efficiency and quantum yield in the three studied Caralluma species. This reduction of PSII activity occurred in concomitance with a marked rise in non-photochemical quenching of chlorophyll fluorescence denoting operation of non-photochemical energy dissipating mechanisms known to be important for photoprotection of the photosynthetic apparatus.

  1. High-resolution methods for fluorescence retrieval from space

    NARCIS (Netherlands)

    Mazzoni, M.; Falorni, P.; Verhoef, W.

    2010-01-01

    The retrieval from space of a very weak fluorescence signal was studied in the O2A and O2B oxygen atmospheric absorption bands. The accuracy of the method was tested for the retrieval of the chlorophyll fluorescence and reflectance terms contributing to the sensor signal. The radiance at the top of

  2. A Comparison between Local and Global Spaceborne Chlorophyll Indices in the St. Lawrence Estuary

    Directory of Open Access Journals (Sweden)

    Martin A. Montes-Hugo

    2012-11-01

    Full Text Available Spaceborne chlorophyll indices based on red fluorescence (wavelength = 680 nm and water leaving radiance (Lw in the visible spectrum (i.e., 400–700 nm were evaluated in the St Lawrence Estuary (SLE during September of 2011. Relationships between chlorophyll concentration (chl and fluorescence were constructed based on fluorescence line height (FLH measurements derived from a compact laser-based spectrofluorometer developed by ENEA (CASPER and using spectral bands corresponding to the satellite sensor MERIS (MEdium Resolution Imaging Spectrometer. Chlorophyll concentration as estimated from CASPER (chlCASPER was relatively high NE of the MTZ (upper Estuary, and nearby areas influenced by fronts or freshwater plumes derived from secondary rivers (lower estuary. These findings agree with historical shipboard measurements. In general, global chl products calculated from Lw had large biases (up to 27-fold overestimation and 50-fold underestimation with respect to chlCASPER values. This was attributed to the smaller interference of detritus (mineral + organic non-living particulates and chromophoric dissolved organic matter on chlCASPER estimates. We encourage the use of spectrofluorometry for developing and validating remote sensing models of chl in SLE waters and other coastal environments characterized by relatively low to moderate (<10 g·m−3 concentrations of detritus.

  3. Culture of a high-chlorophyll-producing and halotolerant Chlorella vulgaris.

    Science.gov (United States)

    Nakanishi, Koichi; Deuchi, Keiji

    2014-05-01

    In order to increase the value of freshwater algae as raw ingredients for health foods and feed for seawater-based farmed fish, we sought to breed high-chlorophyll halotolerant Chlorella with the objective of generating strains with both high chlorophyll concentrations (≥ 5%) and halotolerance (up to 1% NaCl). We used the Chlorella vulgaris K strain in our research institute culture collection and induced mutations with UV irradiation and acriflavine which is known to effect mutations of mitochondrial DNA that are associated with chlorophyll production. Screenings were conducted on seawater-based "For Chlorella spp." (FC) agar medium, and dark-green-colored colonies were visually selected by macroscopic inspection. We obtained a high-chlorophyll halotolerant strain (designated C. vulgaris M-207A7) that had a chlorophyll concentration of 6.7% (d.m.), a level at least three-fold higher than that of K strain. This isolate also exhibited a greater survival rate in seawater that of K strain. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. Chlorophyll mediated photodynamic inactivation of blue laser on Streptococcus mutans

    Science.gov (United States)

    Astuti, Suryani Dyah; Zaidan, A.; Setiawati, Ernie Maduratna; Suhariningsih

    2016-03-01

    Photodynamic inactivation is an inactivation method in microbial pathogens that utilize light and photosensitizer. This study was conducted to investigate photodynamic inactivation effects of low intensity laser exposure with various dose energy on Streptococcus mutans bacteria. The photodynamic inactivation was achieved with the addition of chlorophyll as photosensitizers. To determine the survival percentage of Streptococcus mutans bacteria after laser exposure, the total plate count method was used. For this study, the wavelength of the laser is 405 nm and variables of energy doses are 1.44, 2.87, 4.31, 5.74, 7.18, and 8.61 in J/cm2. The results show that exposure to laser with energy dose of 7.18 J/cm2 has the best photodynamic inactivation with a decrease of 78% in Streptococcus

  5. Identification of genes associated with chlorophyll accumulation in flower petals.

    Directory of Open Access Journals (Sweden)

    Akemi Ohmiya

    Full Text Available Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of genes related to chlorophyll metabolism in different stages of non-green (red and white petals (very low chlorophyll content, pale-green petals (low chlorophyll content, and leaves (high chlorophyll content of carnation (Dianthus caryophyllus L.. The expression of many genes encoding chlorophyll biosynthesis enzymes, in particular Mg-chelatase, was lower in non-green petals than in leaves. Non-green petals also showed higher expression of genes involved in chlorophyll degradation, including STAY-GREEN gene and pheophytinase. These data suggest that the absence of chlorophylls in carnation petals may be caused by the low rate of chlorophyll biosynthesis and high rate of degradation. Similar results were obtained by the analysis of Arabidopsis microarray data. In carnation, most genes related to chlorophyll biosynthesis were expressed at similar levels in pale-green petals and leaves, whereas the expression of chlorophyll catabolic genes was higher in pale-green petals than in leaves. Therefore, we hypothesize that the difference in chlorophyll content between non-green and pale-green petals is due to different levels of chlorophyll biosynthesis. Our study provides a basis for future molecular and genetic studies on organ-specific chlorophyll accumulation.

  6. Afterglow of chlorophyll in vivo and photosynthesis

    NARCIS (Netherlands)

    Goedheer, J.C.

    1962-01-01

    Two pigment systems are involved in the afterglow of chlorophyll a-containing cells. Absorption in only one of these systems (promoting or “p” system) is effective in producing luminescence. If light is absorbed simultaneously by the other (quenching or “q” system), a decrease in luminescence

  7. SHORT COMMUNICATION ISOLATION OF CHLOROPHYLL A ...

    African Journals Online (AJOL)

    a

    chemical synthesis was reported by Woodward and co-workers [3]. The first successful separation of chlorophyll was reported by Tswett [4] giving birth to modern chromatographic techniques. A variety of chromatographic procedures, including paper [5], thin-layer [6], conventional column [7], and high-performance liquid ...

  8. Relationships between nitrate, chlorophyll and chromaticity values ...

    African Journals Online (AJOL)

    ajl yemi

    2011-11-28

    Nov 28, 2011 ... pigment concentration and one or more chromatic parameters such as carotenoids in apricots (Ruiz et al.,. 2005) and orange juice (Melendez-Martinez et al., 2003), lycopene in tomatoes (Arias et al., 2000; Hyman et al.,. 2004), anthocyanins in Acer leaves (Schmitzer et al.,. 2009) and chlorophyll in pepper ...

  9. Forecasting Ocean Chlorophyll in the Equatorial Pacific

    Directory of Open Access Journals (Sweden)

    Cecile S. Rousseaux

    2017-07-01

    Full Text Available Using a global ocean biogeochemical model combined with a forecast of physical oceanic and atmospheric variables from the NASA Global Modeling and Assimilation Office, we assess the skill of a chlorophyll concentrations forecast in the Equatorial Pacific for the period 2012–2015 with a focus on the forecast of the onset of the 2015 El Niño event. Using a series of retrospective 9-month hindcasts, we assess the uncertainties of the forecasted chlorophyll by comparing the monthly total chlorophyll concentration from the forecast with the corresponding monthly ocean chlorophyll data from the Suomi-National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (S-NPP VIIRS satellite. The forecast was able to reproduce the phasing of the variability in chlorophyll concentration in the Equatorial Pacific, including the beginning of the 2015–2016 El Niño. The anomaly correlation coefficient (ACC was significant (p < 0.05 for forecast at 1-month (R = 0.33, 8-month (R = 0.42 and 9-month (R = 0.41 lead times. The root mean square error (RMSE increased from 0.0399 μg chl L−1 for the 1-month lead forecast to a maximum of 0.0472 μg chl L−1 for the 9-month lead forecast indicating that the forecast of the amplitude of chlorophyll concentration variability was getting worse. Forecasts with a 3-month lead time were on average the closest to the S-NPP VIIRS data (23% or 0.033 μg chl L−1 while the forecast with a 9-month lead time were the furthest (31% or 0.042 μg chl L−1. These results indicate the potential for forecasting chlorophyll concentration in this region but also highlights various deficiencies and suggestions for improvements to the current biogeochemical forecasting system. This system provides an initial basis for future applications including the effects of El Niño events on fisheries and other ocean resources given improvements identified in the analysis of these results.

  10. Drivers of fluorescent dissolved organic matter in the global epipelagic ocean

    DEFF Research Database (Denmark)

    Catalá, T.S.; Álvarez-Salgado, X. A.; Otero, J.

    2016-01-01

    Fluorescent dissolved organic matter (FDOM) in open surface waters (... was substantially larger (> 70%) than for the amino acid-like components (oxygen utilisation followed by chlorophyll a. Positive non-linear relationships between both predictor variables...

  11. Fluorescence, Aqua MODIS, NPP, 0.125 degrees, Gulf of Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS measures chlorophyll fluorescence, which gives insight into the physiology of phytoplankton in the ocean. When phytoplankton are under stress, the rate at...

  12. Fluorescence, Aqua MODIS, NPP, 0.05 degrees, West US, Science Quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS measures chlorophyll fluorescence, which gives insight into the physiology of phytoplankton in the ocean. When phytoplankton are under stress, the rate at...

  13. Influence of vermicompost humic acid on chlorophyll content and ...

    African Journals Online (AJOL)

    S

    2016-11-23

    Nov 23, 2016 ... VHA applied improved total chlorophyll, chlorophyll a-b at concentrations of 20 and 50 ... wheat and maize (Hossain, 2014), so it is considered a ..... crops because of high content of many available nutrients ..... Effect of foliar.

  14. Investigation into robust spectral indices for leaf chlorophyll estimation

    CSIR Research Space (South Africa)

    Main, R

    2011-11-01

    Full Text Available chlorophyll spectral indices have been assessed, using leaf level hyperspectral data collected from three crop species and a variety of savanna tree species. Linear regression between total leaf chlorophyll content and bootstrapping were used to determine...

  15. Comprehensive chlorophyll composition in the main edible seaweeds.

    Science.gov (United States)

    Chen, Kewei; Ríos, José Julián; Pérez-Gálvez, Antonio; Roca, María

    2017-08-01

    Natural chlorophylls present in seaweeds have been studied regarding their biological activities and health benefit effects. However, detailed studies regarding characterization of the complete chlorophyll profile either qualitatively and quantitatively are scarce. This work deals with the comprehensive spectrometric study of the chlorophyll derivatives present in the five main coloured edible seaweeds. The novel complete MS(2) characterization of five chlorophyll derivatives: chlorophyll c2, chlorophyll c1, purpurin-18 a, pheophytin d and phytyl-purpurin-18 a has allowed to obtain fragmentation patterns associated with their different structural features. New chlorophyll derivatives have been identified and quantified by first time in red, green and brown seaweeds, including some oxidative structures. Quantitative data of the chlorophyll content comes to achieve significant information for food composition databases in bioactive compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Monitoring of Chlorophyll in Water Reservoirs Using Satellite Data

    Science.gov (United States)

    Bocharov, A. V.; Tikhomirov, O. A.; Khizhnyak, S. D.; Pakhomov, P. M.

    2017-05-01

    The statistical relationship between Landsat sensor data and the chlorophyll concentration in Ivankovo reservoir was studied. A regression relationship describing the dependence of the pixel values of satellite images on the in situ measured (using electronic spectroscopy) chlorophyll concentration in water and allowing an analysis of the spatial distribution of the reservoir chlorophyll concentration was found. The trophic status, amount of phytoplankton biomass, and primary production were estimated based on the chlorophyll concentration data.

  17. A biliverdin-binding cyanobacteriochrome from the chlorophyll d-bearing cyanobacterium Acaryochloris marina.

    Science.gov (United States)

    Narikawa, Rei; Nakajima, Takahiro; Aono, Yuki; Fushimi, Keiji; Enomoto, Gen; Ni-Ni-Win; Itoh, Shigeru; Sato, Moritoshi; Ikeuchi, Masahiko

    2015-01-22

    Cyanobacteriochromes (CBCRs) are linear tetrapyrrole-binding photoreceptors in cyanobacteria that absorb visible and near-ultraviolet light. CBCRs are divided into two types based on the type of chromophore they contain: phycocyanobilin (PCB) or phycoviolobilin (PVB). PCB-binding CBCRs reversibly photoconvert at relatively long wavelengths, i.e., the blue-to-red region, whereas PVB-binding CBCRs reversibly photoconvert at shorter wavelengths, i.e., the near-ultraviolet to green region. Notably, prior to this report, CBCRs containing biliverdin (BV), which absorbs at longer wavelengths than do PCB and PVB, have not been found. Herein, we report that the typical red/green CBCR AM1_1557 from the chlorophyll d-bearing cyanobacterium Acaryochloris marina can bind BV almost comparable to PCB. This BV-bound holoprotein reversibly photoconverts between a far red light-absorbing form (Pfr, λmax = 697 nm) and an orange light-absorbing form (Po, λmax = 622 nm). At room temperature, Pfr fluoresces with a maximum at 730 nm. These spectral features are red-shifted by 48~77 nm compared with those of the PCB-bound domain. Because the absorbance of chlorophyll d is red-shifted compared with that of chlorophyll a, the BV-bound AM1_1557 may be a physiologically relevant feature of A. marina and is potentially useful as an optogenetic switch and/or fluorescence imager.

  18. Genetic dissection of chlorophyll content at different growth stages in ...

    Indian Academy of Sciences (India)

    Ten of 17 additive QTLs for chlorophyll content were persistently expressed at more than two growth stages, which suggest developmentally regulated loci controlling genetics for chlorophyll content in different growth stages in wheat. One novel major QTL for chlorophyll content was closely linked with the PCR marker ...

  19. Effect of Sodium Dodecyl Sulfate on Structure and Spectroscopic Characteristics of Water-Soluble Chlorophyll Protein Complex Isolated from Stems of Lepidium virginicum

    OpenAIRE

    Kenichi, Tabata; Shigeru, Itoh; Masaharu, Sugawa; Mitsuo, Nishimura; Department of Biology, Faculty of Science, Kyushu University; Department of Biology, Faculty of Science, Kyushu University:(Present)National Institute for Basic Biology; Department of Biology, Faculty of Science, Kyushu University; Department of Biology, Faculty of Science, Kyushu University

    1983-01-01

    The relationship between structure and spectroscopic characteristics of the water-soluble chlorophyll protein complex isolated from stems of Lepidium virginicum (CP663S) was studied. Addition of 0.08% SDS induced a red shift of the 663 nm absorption maximum. At the same time, under excitation at 435 nm, the maximum of fluorescence emission shifted from 672 nm to 675 nm and the fluorescence yield increased. When CP663S was excited at 480 nm, the 660 nm emission band of chlorophyll b became mor...

  20. Reflectance variation within the in-chlorophyll centre waveband for robust retrieval of leaf chlorophyll content.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    Full Text Available The in-chlorophyll centre waveband (ICCW (640-680 nm is the specific chlorophyll (Chl absorption band, but the reflectance in this band has not been used as an optimal index for non-destructive determination of plant Chl content in recent decades. This study develops a new spectral index based solely on the ICCW for robust retrieval of leaf Chl content for the first time. A glasshouse experiment for solution-culture of one chlorophyll-deficient rice mutant and six wild types of rice genotypes was conducted, and the leaf reflectance (400-900 nm was measured with a high spectral resolution (1 nm spectrophotometer and the contents of chlorophyll a (Chla, chlorophyll b (Chlb and chlorophyll a+b (Chlt of the rice leaves were determined. It was found that the reflectance curves from 640 nm to 674 nm and from 675 nm to 680 nm of the low-chlorophyll mutant leaf were drastically steeper than that of the wild types in the ICCW. The new index based on the reflectance variation within ICCW, the difference of the first derivative sum within the ICCW (DFDS_ICCW, was highly sensitive (r = -0.77, n = 93, P0.05 to Chlt when the leaf Chlt was higher than 200 mg/m(2. The best equations of R-ICCW and DFDS_ICCW yielded an RMSE of 78.7, 32.9 and 107.3 mg/m(2, and an RMSE of 37.4, 16.0 and 45.3 mg/m(-2, respectively, for predicting Chla, Chlb and Chlt. The new index could rank in the top 10 for prediction of Chla and Chlt as compared with the 55 existing indices. Additionally, most of the 55 existing Chl-related VIs performed robustly or strongly in simultaneous prediction of leaf Chla, Chlb and Chlt.

  1. Reflectance variation within the in-chlorophyll centre waveband for robust retrieval of leaf chlorophyll content.

    Science.gov (United States)

    Zhang, Jing; Huang, Wenjiang; Zhou, Qifa

    2014-01-01

    The in-chlorophyll centre waveband (ICCW) (640-680 nm) is the specific chlorophyll (Chl) absorption band, but the reflectance in this band has not been used as an optimal index for non-destructive determination of plant Chl content in recent decades. This study develops a new spectral index based solely on the ICCW for robust retrieval of leaf Chl content for the first time. A glasshouse experiment for solution-culture of one chlorophyll-deficient rice mutant and six wild types of rice genotypes was conducted, and the leaf reflectance (400-900 nm) was measured with a high spectral resolution (1 nm) spectrophotometer and the contents of chlorophyll a (Chla), chlorophyll b (Chlb) and chlorophyll a+b (Chlt) of the rice leaves were determined. It was found that the reflectance curves from 640 nm to 674 nm and from 675 nm to 680 nm of the low-chlorophyll mutant leaf were drastically steeper than that of the wild types in the ICCW. The new index based on the reflectance variation within ICCW, the difference of the first derivative sum within the ICCW (DFDS_ICCW), was highly sensitive (r = -0.77, n = 93, P0.05) to Chlt when the leaf Chlt was higher than 200 mg/m(2). The best equations of R-ICCW and DFDS_ICCW yielded an RMSE of 78.7, 32.9 and 107.3 mg/m(2), and an RMSE of 37.4, 16.0 and 45.3 mg/m(-2), respectively, for predicting Chla, Chlb and Chlt. The new index could rank in the top 10 for prediction of Chla and Chlt as compared with the 55 existing indices. Additionally, most of the 55 existing Chl-related VIs performed robustly or strongly in simultaneous prediction of leaf Chla, Chlb and Chlt.

  2. Fluorescence and Spectral Imaging

    Directory of Open Access Journals (Sweden)

    Ralph S. DaCosta

    2007-01-01

    Full Text Available Early identification of dysplasia remains a critical goal for diagnostic endoscopy since early discovery directly improves patient survival because it allows endoscopic or surgical intervention with disease localized without lymph node involvement. Clinical studies have successfully used tissue autofluorescence with conventional white light endoscopy and biopsy for detecting adenomatous colonic polyps, differentiating benign hyperplastic from adenomas with acceptable sensitivity and specificity. In Barrett's esophagus, the detection of dysplasia remains problematic because of background inflammation, whereas in the squamous esophagus, autofluorescence imaging appears to be more dependable. Point fluorescence spectroscopy, although playing a crucial role in the pioneering mechanistic development of fluorescence endoscopic imaging, does not seem to have a current function in endoscopy because of its nontargeted sampling and suboptimal sensitivity and specificity. Other point spectroscopic modalities, such as Raman spectroscopy and elastic light scattering, continue to be evaluated in clinical studies, but still suffer the significant disadvantages of being random and nonimaging. A recent addition to the fluorescence endoscopic imaging arsenal is the use of confocal fluorescence endomicroscopy, which provides real-time optical biopsy for the first time. To improve detection of dysplasia in the gastrointestinal tract, a new and exciting development has been the use of exogenous fluorescence contrast probes that specifically target a variety of disease-related cellular biomarkers using conventional fluorescent dyes and novel potent fluorescent nanocrystals (i.e., quantum dots. This is an area of great promise, but still in its infancy, and preclinical studies are currently under way.

  3. Carotenoid, chlorophyll, and chlorophyll-derived compounds in grapes and port wines.

    Science.gov (United States)

    Mendes-Pinto, Maria Manuela; Silva Ferreira, António César; Caris-Veyrat, Catherine; Guedes de Pinho, Paula

    2005-12-28

    Carotenoids and chlorophyll-derived compounds in grapes and Port wines were investigated by HPLC-DAD and HPLC-DAD-MS (ESP+) analysis. A total of 13 carotenoid and chlorophyll-derived compounds are formally reported in grapes, 3 are identified for the first time, pheophytins a and b and (13Z)-beta-carotene, and 3 others remain unknown. In Port wines 19 compounds with carotenoid or chlorophyll-like structures are present, 8 still unidentified. The young wines showed higher total carotenoid content and chlorophyll-like compounds compared to aged Ports, with lutein and beta-carotene as major carotenoids. Among samples analyzed of monovarietal Vitis vinifera L. cultivar wines produced with the five most important Douro varieties, Tinta Roriz contained the highest levels of carotenoids and Touriga Franca the lowest. The forced-aging study indicated that lutein was more sensitive to temperature than beta-carotene. Additionally, aged wines showed higher ratios of beta-carotene/lutein concentrations compared to new Ports. Rates of degradation of chlorophyll derivative compounds were higher than those for carotene and lutein.

  4. Fluorescent minerals - A potential source of UV protection and visible light for the growth of green algae and cyanobacteria in extreme cosmic environments

    Science.gov (United States)

    Omairi, Tareq; Wainwright, Milton

    2015-07-01

    We propose that green algae (Chlorella variabilis and Dunaliella tertiolecta) and cyanobacteria (Synechococcus elongatus and Nostoc commune) can grow inside fluorescent rock minerals which convert damaging UV light to visible light, thereby allowing these organisms to survive and thrive in UV-rich environments without (or with limited) visible light, which would otherwise be inimical to them. The four microorganisms were incubated inside fluorescent rocks composed of fluorite, calcite and pyrite. The resultant growth was then measured following exposure to UV radiation, with the use of optical density and measurement of chlorophyll concentration. Results show that the microorganisms were shielded from harmful UV in these semi-transparent rocks, while at the same time benefiting from the fact that the minerals converted UV to visible light; this have been shown by a statistically significant increase in their growth, which although lower than when the cells were incubated in sunlight, was significantly higher than in controls incubated in the dark.

  5. Fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2016-01-01

    Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...... the foundations of the fluorescence phenomenon, introduces some general methodologies and provides selected examples on applications focused to disentangle structural and dynamical aspects of biological processes....

  6. Stay-green regulates chlorophyll and chlorophyll-binding protein degradation during senescence.

    Science.gov (United States)

    Hörtensteiner, Stefan

    2009-03-01

    Stay-green mutants are delayed in leaf senescence and have been identified from different plant species, including many crops. Functional stay-greens have the potential to increase plant productivity. In cosmetic stay-greens, however, retention of chlorophyll during senescence is uncoupled from a decline of photosynthetic capacity in these mutants. For many cosmetic stay-green mutants, including Gregor Mendel's famous green cotyledon pea variety, molecular defects were recently identified in orthologous stay-green genes. Stay-green genes encode members of a new family of chloroplast-located proteins, which are likely to function in dismantling of photosynthetic chlorophyll-apoprotein complexes. Their activity is considered as a prerequisite for both chlorophyll and apoprotein degradation during senescence.

  7. Simulation de la fluorescence de la végétation mesurée depuis une orbite géostationnaire

    OpenAIRE

    Rhoul, Camill

    2016-01-01

    This thesis is about remote sensing of the chlorophyll fluorescence to monitor the vegetation from space. Recent work shows that the diurnal variation of the chlorophyll fluorescence is the most discriminative criterion to assess vegetation physiological state, especially water stress. To ensure several measurements in a day, a geostationary orbit is considered.We created a passive imager to assess the diurnal cycles of fluorescence in the O2-A absorption band. It employs an interferential fi...

  8. Far-red fluorescence : A direct spectroscopic marker for LHCII oligomer formation in non-photochemical quenching

    NARCIS (Netherlands)

    Miloslavina, Yuliya; Wehner, Antje; Lambrev, Petar H.; Wientjes, Emilie; Reus, Michael; Garab, Gyozo; Croce, Roberta; Holzwarth, Alfred R.; Garab, Győző

    2008-01-01

    Time-resolved fluorescence on oligomers of the main light-harvesting complex from higher plants indicate that in vitro oligomerization leads to the formation of a weakly coupled inter-trimer chlorophyll-chlorophyll (Chl) exciton state which converts in tens of ps into a state which is spectrally

  9. Spinach seed quality - potential for combining seed size grading and chlorophyll flourescence sorting

    DEFF Research Database (Denmark)

    Deleuran, Lise Christina; Olesen, Merete Halkjær; Boelt, Birte

    2013-01-01

    Spinach (Spinacia oleracea L.) seed quality is important for subsequent establishment of baby leaf and other spinach products. The indeterminate flowering pattern in spinach produces seeds of different sizes, and consequently a non-uniform seed lot. Sorting seeds based on novel sorting methods.......5–3.25 mm size seeds had germinated on day 3 than both their larger and smaller counterparts at the later time of harvest (H4). Seeds with a diameter below 2.5 mm displayed the lowest MGT. Commercially, the use of chlorophyll fluorescence (CF)-sorted seeds, in combination with seed size sorting, may provide...

  10. Contrast agent free detection of bowel perforation using chlorophyll derivatives from food plants

    Science.gov (United States)

    Han, Jung Hyun; Jo, Young Goun; Kim, Jung Chul; Lee, Jee-Bum; Kim, Yong-Chul; Kang, Hoonsoo; Hwang, In-Wook

    2016-01-01

    Chlorophylls occur abundantly in food plants and show bright emission bands at long-wavelength regions (∼675 and ∼720 nm) compared to the autofluorescence of animal organs and peritoneal fluids. The use of these emissions as biomarkers for monitoring bowel perforation with a modality that does not involve synthetic contrast agents seems promising. To validate this, we measured the fluorescence spectra of rat organs, human peritoneal and intestinal fluids, and human intestinal fluids diluted with physiological saline. The developed technique showed a high detection sensitivity (∼50 ppm) under irrigation for abdominal surgery, highlighting the potential of this tool in the surgical setting.

  11. The Magnesium Chelation Step in Chlorophyll Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gregory L. Dilworth, Ph.D Chemical Sciences, Geosciences and Biosciences Division Office of Basis Energy Sciences, greg.dilworth@science.doe.gov

    2001-01-17

    The progress described in this report encompasses work supported by DOE grant DE-FG09-89ER13989 for the period 2/15/92 to the present 6/14/94. The goals of the project were to continue investigating the enzymology of Mg-chelatase and to investigate the co-regulation of heme and chlorophyll formation in intact plastids. During this period the laboratory had additional support (two years) from USDA to investigate heme metabolism in chloroplasts. This report is arranged so that the progress is described by reference to manuscripts which are published, under review or in preparation.

  12. The Use of a Chlorophyll Meter (SPAD-502) for Field Determinations of Red Mangrove (Rhizophora Mangle L.) Leaf Chlorophyll Amount

    Science.gov (United States)

    Connelly, Xana M.

    1997-01-01

    The red mangrove Rhizophora mangle L., is a halophytic woody spermatophyte common to the land-sea interface of tropical and subtropical intertidal zones. It has been reported that 60 to 75% of the coastline of the earth's tropical regions are lined with mangroves. Mangroves help prevent shoreline erosion, provide breeding, nesting and feeding areas for many marine animals and birds. Mangroves are important contributors of primary production in the coastal environment, and this is largely proportional to the standing crop of leaf chlorophylls. Higher intensities of ultraviolet radiation, resulting from stratospheric ozone depletion, can lead to a reduction of chlorophyll in terrestrial plants. Since the most common method for determining chlorophyll concentration is by extraction and this is labor intensive and time consuming, few studies on photosynthetic pigments of mangroves have been reported. Chlorophyll meter readings have been related to leaf chlorophyll content in apples and maples. It has also been correlated to nitrogen status in corn and cotton. Peterson et al., (1993) used a chlorophyll meter to detect nitrogen deficiency in crops and in determining the need for additional nitrogen fertilizer. Efforts to correlate chlorophyll meter measurements to chlorophyll content of mangroves have not been reported. This paper describes the use of a hand-held chlorophyll meter (Minolta SPAD-502) to determine the amount of red mangrove foliar chlorophyll present in the field.

  13. Low-cost chlorophyll meter (LCCM): portable measuring device for leaf chlorophyll

    Science.gov (United States)

    Hutomo E. P., Evan; Adibawa, Marcelinus Alfasisurya S.; Prilianti, Kestrilia R.; Heriyanto, Heriyanto; Brotosudarmo, Tatas H. P.

    2016-11-01

    Portable leaf chlorophyll meter, named low-cost chlorophyll meter (LCCM), has been created. This device was created to help farmer determining the health condition of plant based on the greenness level of leaf surface. According to previous studies, leaf greenness with a certain amount of chlorophyll level has a direct correlation with the amount of nitrogen in the leaf that indicates health of the plant and this fact needed to provide an estimate of further measures to keep the plants healthy. Device that enables to measure the leaf color change is soil plant analysis development (SPAD) meter 502 from Konica Minolta but it is relatively expensive. To answer the need of low-cost chlorophyll scanner device, this research conducted experiment using light reflectance as the base mechanism. Reflectance system from LCCM consists of near-infrared light emitting diode (LED) and red LED as light resources and photodiode. The output from both of light resources calculated using normalized difference vegetation index (NDVI) formula as the results fetched and displayed on the smartphone application using Bluetooth communication protocol. Finally, the scanner has been made as well as the Android application named NDVI Reader. The LCCM system which has been tested on 20 sample of cassava leaf with SPAD meter as a variable control showed coefficient of determination 0.9681 and root-mean-square error (RMSE) 0.014.

  14. Stereoelectronic properties of aggregated chlorophyll systems

    Energy Technology Data Exchange (ETDEWEB)

    Christoffersen, R. E.; Maggiora, G. M.

    1979-09-01

    During the first nine months of the current contract, significant progress has occurred in several areas. All SCF CI studies of the singlet and triplet states of the neutral molecules Et-Chl a, Et-Pheo a, Et-BChl a, and Et-BPheo a, and the doublet states of the ..pi..-cation radicals Et-Chl a/sup +/. and Et-BChl a/sup +/. have now been completed. In addition, SCF CI calculations on BPheo a/sup -/. indicate that ..pi..-anion radicals can also be studied using the present approach. Similar work on a number of other ..pi..-cation and ..pi..-anion radicals is currently underway. Preliminary SCF CI studies have also been completed for benzoquinone and dihydroquinone, and studies on benzoquinone/sup -/. should be completed by the end of this year. The development and characterization of an empirical potential function is nearly complete, and data from selected systems is summarized. Implementation of a more efficient, quadratically convergent energy minimization procedure is also being carried out. This procedure should make it possible to study the geometry and properties of dimeric chlorophyll systems as well as various ligand-chlorophyll systems. Developmental work is continuing on the direct calculation of optical rotatory strengths.

  15. The magnesium chelation step in chlorophyll biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, J.D.

    1991-01-01

    The biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins and lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX. Insertion of iron leads to heme, while insertion of magnesium leads to chlorophyll. The Mg-chelatase from intact cucumber chloroplasts has been characterized with regard to substrate specificity, regulation, ATP requirement, and a requirement for intact chloroplasts. Mg-chelatase was isolated from maize, barley and peas and characterized in order to circumvent the intact chloroplast requirement of cucumber Mg-chelatase. Pea Mg-chelatase activity is higher than cucumber Mg-chelatase activity, and lacks the requirement for intact chloroplasts. Studies on isolated pea Mg-chelatase have shown more cofactors are required for the reaction than are seen with ferrochelatase, indicating a greater opportunity for regulatory control of this pathway. Two of the cofactors are proteins, and there appears to be a requirement for a protease-sensitive component which is outside the outer envelope. We are developing a continuous spectrophotometric assay for Mg-chelatase activity, and an assay for free heme which has shown heme efflux from intact chloroplasts. 18 refs. (MHB)

  16. An advective mechanism for deep chlorophyll maxima formation in southern Drake Passage

    Science.gov (United States)

    Erickson, Zachary K.; Thompson, Andrew F.; Cassar, Nicolas; Sprintall, Janet; Mazloff, Matthew R.

    2016-10-01

    We observe surface and subsurface fluorescence-derived chlorophyll maxima in southern Drake Passage during austral summer. Backscatter measurements indicate that the deep chlorophyll maxima (DCMs) are also deep biomass maxima, and euphotic depth estimates show that they lie below the euphotic layer. Subsurface, offshore and near-surface, onshore features lie along the same isopycnal, suggesting advective generation of DCMs. Temperature measurements indicate a warming of surface waters throughout austral summer, capping the winter water (WW) layer and increasing off-shelf stratification in this isopycnal layer. The outcrop position of the WW isopycnal layer shifts onshore, into a surface phytoplankton bloom. A lateral potential vorticity (PV) gradient develops, such that a down-gradient PV flux is consistent with offshore, along-isopycnal tracer transport. Model results are consistent with this mechanism. Subduction of chlorophyll and biomass along isopycnals represents a biological term not observed by surface satellite measurements which may contribute significantly to the strength of the biological pump in this region.

  17. Antimutagenic activities of common vegetables and their chlorophyll content

    Energy Technology Data Exchange (ETDEWEB)

    Lai, C.N.; Butler, M.A.; Matney, T.S.

    1980-01-01

    Aqueous and acetone extractions of some common vegetables inhibited the activation of 3-methylcholanthrene and benzo(a)pyrene in the Ames Salmonella gene reversion mutagenesis/mammalian microsomal activation assay. The potency of the inhibitory activity was correlated with the chlorophyll content of the acetone extracts. The aqueous fractions contained sufficient histidine to interfere with the interpretation of the result. However, grouping the aqueous extracts from vegetables yielding low, medium, and high levels of histidine allowed comparison between antimutagenic activity and chlorophyll content. Increasing chlorophyll contents corresponded to increasing antimutagenic activities in all 3 groups. Sodium copper chlorophyllin demonstrated comparable inhibitory activity when compared at the same chlorophyll level.

  18. Effet de la salinité sur la fluorescence chlorophyllienne, la teneur en proline et la production florale de trois espèces ornementales

    Directory of Open Access Journals (Sweden)

    Mathlouthi, M.

    2005-01-01

    Full Text Available Effect of Chloride Sodium on Chlorophyll Fluorescence, Plant Proline Content and Flowers Production of Three Ornamental Species. Three ornamental species (Zinnia elegans, Tagetes patula and Petunia hybrida were used to test sodium chloride effect on chlorophyll fluorescence, plant proline content and flowers production. Three treatments were used in this trial: 0, 2 and 4 g of Nacl.l-1 of irrigation water. The results showed that chlorophyll fluorescence was not affected by sodium chloride treatment but plant proline content increased and flowers production decreased as NaCl doses increase.

  19. Fluorescence imaging for investigating the efficiency of formulations, adjuvants and application systems

    NARCIS (Netherlands)

    Ruiter, de H.; Schoor, van der R.; Jalink, H.

    2005-01-01

    Several herbicides reduce, directly or indirectly, the efficiency of photosynthesis of plants. As a consequence, the fluorescence of the chlorophyll increases. The relative increase of fluorescence [(Fm-F0)/Fm] can be used to compare the influence of formulations and adjuvants on the activity of

  20. Registration of fluorescence in biomolecular solutions using dynamic pin photodiode

    Science.gov (United States)

    Savchenko, E. A.; Nepomnyashchaya, E. K.; Dyubo, D. B.; Velichko, E. N.; Tsybin, O. Yu

    2017-11-01

    The application of a dynamic pin-photodiode as a recording device of the fluorescence radiation is considered. An experimental setup for registration of luminescence signals from biomolecules excited by laser radiation was developed. Rhodamine 6G and chlorophyll were investigated.

  1. Fluorescence spectral properties of outer antenna LHC II

    CERN Document Server

    He Jun Fang; Zhang, Shu; He Fang Tao; Ren Zhao You; Li Liang Bi; Kuang Ting Yun

    2002-01-01

    Outer antenna LHC II acts to absorb and transfer energy for photosynthesis. The authors studied the fluorescence properties of LHC II of spinach with scanning imaging fluorescence spectroscopy. After it had been excited by 514.5 nm laser, the integral fluorescence spectrum of LHC II was detected. It was shown that energy transfer existed between carotenoid and chlorophyll. Seven bands of LHC II fluorescence emission were resolved by Gauss combination, viz. 656.7, 664.6, 671.5, 677.2, 683.5, 689.6, 695.3 nm, and the percentages of them were 3.0%, 13.1%,13.3%, 21.1%, 13.2%, 33.3%, 3.0% respectively. The emission of 658.7 nm was attributed to chlorophyll b, the other emission bands were produced by chlorophyll a molecules with the maximum absorption 662, 670/671, 676, 680 nm and over 690 nm. The band 656.7 nm, whose percentage was 3.0%, shows that the most energy was absorbed by chlorophyll a. The percentage of band 689.6 nm was the most, which was possibly correlated with one type of self protective mechanism o...

  2. Characterisation of estuarine intertidal macroalgae by laser-induced fluorescence

    DEFF Research Database (Denmark)

    Gameiro, Carla; Utkin, Andrei B.; Sousa Dias Cartaxana, Paulo Jorge

    2015-01-01

    spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick...

  3. The role of chlorophyll b in photosynthesis: Hypothesis

    Directory of Open Access Journals (Sweden)

    Park Hyoungshin

    2001-10-01

    Full Text Available Abstract Background The physico-chemical properties of chlorophylls b and c have been known for decades. Yet the mechanisms by which these secondary chlorophylls support assembly and accumulation of light-harvesting complexes in vivo have not been resolved. Presentation Biosynthetic modifications that introduce electronegative groups on the periphery of the chlorophyll molecule withdraw electrons from the pyrrole nitrogens and thus reduce their basicity. Consequently, the tendency of the central Mg to form coordination bonds with electron pairs in exogenous ligands, a reflection of its Lewis acid properties, is increased. Our hypothesis states that the stronger coordination bonds between the Mg atom in chlorophyll b and chlorophyll c and amino acid sidechain ligands in chlorophyll a/b- and a/c-binding apoproteins, respectively, enhance their import into the chloroplast and assembly of light-harvesting complexes. Testing Several apoproteins of light-harvesting complexes, in particular, the major protein Lhcb1, are not detectable in leaves of chlorophyll b-less plants. A direct test of the hypothesis – with positive selection – is expression, in mutant plants that synthesize only chlorophyll a, of forms of Lhcb1 in which weak ligands are replaced with stronger Lewis bases. Implications The mechanistic explanation for the effects of deficiencies in chlorophyll b or c points to the need for further research on manipulation of coordination bonds between these chlorophylls and chlorophyll-binding proteins. Understanding these interactions will possibly lead to engineering plants to expand their light-harvesting antenna and ultimately their productivity.

  4. Phytohormone and Light Regulation of Chlorophyll Degradation

    Directory of Open Access Journals (Sweden)

    Xiaoyu Zhu

    2017-11-01

    Full Text Available Degreening, due to the net loss of chlorophyll (Chl, is the most prominent symptom during the processes of leaf senescence, fruit ripening, and seed maturation. Over the last decade or so, extensive identifications of Chl catabolic genes (CCGs have led to the revelation of the biochemical pathway of Chl degradation. As such, exploration of the regulatory mechanism of the degreening process is greatly facilitated. During the past few years, substantial progress has been made in elucidating the regulation of Chl degradation, particularly via the mediation of major phytohormones' signaling. Intriguingly, ethylene and abscisic acid's signaling have been demonstrated to interweave with light signaling in mediating the regulation of Chl degradation. In this review, we briefly summarize this progress, with an effort on providing a framework for further investigation of multifaceted and hierarchical regulations of Chl degradation.

  5. Phytohormone and Light Regulation of Chlorophyll Degradation

    Science.gov (United States)

    Zhu, Xiaoyu; Chen, Junyi; Qiu, Kai; Kuai, Benke

    2017-01-01

    Degreening, due to the net loss of chlorophyll (Chl), is the most prominent symptom during the processes of leaf senescence, fruit ripening, and seed maturation. Over the last decade or so, extensive identifications of Chl catabolic genes (CCGs) have led to the revelation of the biochemical pathway of Chl degradation. As such, exploration of the regulatory mechanism of the degreening process is greatly facilitated. During the past few years, substantial progress has been made in elucidating the regulation of Chl degradation, particularly via the mediation of major phytohormones' signaling. Intriguingly, ethylene and abscisic acid's signaling have been demonstrated to interweave with light signaling in mediating the regulation of Chl degradation. In this review, we briefly summarize this progress, with an effort on providing a framework for further investigation of multifaceted and hierarchical regulations of Chl degradation. PMID:29163624

  6. Nonspectroscopic imaging for quantitative chlorophyll sensing

    Science.gov (United States)

    Kim, Taehoon; Kim, Jeong-Im; Visbal-Onufrak, Michelle A.; Chapple, Clint; Kim, Young L.

    2016-01-01

    Nondestructive imaging of physiological changes in plants has been intensively used as an invaluable tool for visualizing heterogeneous responses to various types of abiotic and biotic stress. However, conventional approaches often have intrinsic limitations for quantitative analyses, requiring bulky and expensive optical instruments for capturing full spectral information. We report a spectrometerless (or spectrometer-free) reflectance imaging method that allows for nondestructive and quantitative chlorophyll imaging in individual leaves in situ in a handheld device format. The combination of a handheld-type imaging system and a hyperspectral reconstruction algorithm from an RGB camera offers simple instrumentation and operation while avoiding the use of an imaging spectrograph or tunable color filter. This platform could potentially be integrated into a compact, inexpensive, and portable system, while being of great value in high-throughput phenotyping facilities and laboratory settings.

  7. Photoinduced electron transfer of chlorophyll in lipid bilayer system

    Indian Academy of Sciences (India)

    Photoinduced electron transfer from chlorophyll- through the interface of dipalmitoylphosphatidylcholine (DPPC) headgroup of the lipid bilayers was studied with electron magnetic resonance (EMR). The photoproduced radicals were identified with electron spin resonance (ESR) and radical yields of chlorophyll- were ...

  8. Chlorophyll modulation of mixed layer thermodynamics in a mixed ...

    Indian Academy of Sciences (India)

    In the Arabian Sea, as the chlorophyll concentrations peak in October (3mg/m3) after the summer plankton bloom induced by coastal upwelling, the chlorophyll induced biological heating enhanced the sea surface temperature (SST) by as much as 0.6°C and sub-layer temperature decreases and sub-layer thickness ...

  9. Genome-wide examination of chlorophyll metabolic genes in maize ...

    African Journals Online (AJOL)

    Jane

    2011-06-22

    Jun 22, 2011 ... Hörtensteiner S (2006). Chlorophyll degradation during senescence. Annu. Rev. Plant. Biol. 57: 55-77. Ilag LL, Kumar AM, Söll D (1994). Light regulation of chlorophyll biosynthesis at the level of 5-aminolevulinate formation in. Arabidopsis. Plant Cell. 6: 265-275. Kumar AM, Csankovszki G, Söll D (1996).

  10. Grain-filling, chlorophyll content in relation with grain yield ...

    African Journals Online (AJOL)

    The beginning of active phase of grain filling corresponded to the beginning of the degradation of chlorophyll content. The velocity of grain filling was negatively correlated to the number of days to heading (DH). Changes in photosynthesis most closely paralleled changes in chlorophyll content. All these changes occurred ...

  11. Identification and classification of vertical chlorophyll patterns in the ...

    African Journals Online (AJOL)

    These characteristic profile shapes were then related to pertinent environmental variables such as sea surface temperature, surface chlorophyll, mixed layer depth and euphotic depth. Partitioning the SOM output map into environmental categories showed large peaks of surface chlorophyll dominating in water with cool ...

  12. Zooplankton biomass to chlorophyll ratios in relation to trophic status ...

    African Journals Online (AJOL)

    2011-09-05

    Sep 5, 2011 ... rising chlorophyll within most individual reservoirs, a trend that is partly .... ate contributions of chlorophyll to mass (see above), the proxy measure of ZB/Chl ..... COETZEE L (2010) Personal communication with Ms Leanne Z. Coetzee, 4 Oct .... to resource utilization and zooplankton succession. J. Plankton ...

  13. An optimal thermal condition for maximal chlorophyll extraction

    Directory of Open Access Journals (Sweden)

    Fu Jia-Jia

    2017-01-01

    Full Text Available This work describes an environmentally friendly process for chlorophyll extraction from bamboo leaves. Shaking water bath and ultrasound cleaner are adopted in this technology, and the influence of temperature of the water bath and ultrasonic cleaner is evaluated. Results indicated that there is an optimal condition for maximal yield of chlorophyll.

  14. Chlorophyll pigment concentration using spectral curvature algorithms - An evaluation of present and proposed satellite ocean color sensor bands

    Science.gov (United States)

    Hoge, Frank E.; Swift, Robert N.

    1986-01-01

    During the past several years symmetric three-band (460-, 490-, 520-nm) spectral curvature algorithm (SCA) has demonstrated rather accurate determination of chlorophyll pigment concentration using low-altitude airborne ocean color data. It is shown herein that the in-water asymmetric SCA, when applied to certain recently proposed OCI (NOAA-K and SPOT-3) and OCM (ERS-1) satellite ocean color bands, can adequately recover chlorophyll-like pigments. These airborne findings suggest that the proposed new ocean color sensor bands are in general satisfactorily, but not necessarily optimally, positioned to allow space evaluation of the SCA using high-precision atmospherically corrected satellite radiances. The pigment concentration recovery is not as good when existing Coastal Zone Color Scanner bands are used in the SCA. The in-water asymmetric SCA chlorophyll pigment recovery evaluations were performed using (1) airborne laser-induced chlorophyll fluorescence and (2) concurrent passive upwelled radiances. Data from a separate ocean color sensor aboard the aircraft were further used to validate the findings.

  15. Prooxidative and antioxidative properties of β-carotene in chlorophyll and riboflavin photosensitized oil-in-water emulsions.

    Science.gov (United States)

    Park, JungWoo; Kim, Tae Soo; Kim, Mi-Ja; Lee, JaeHwan

    2013-09-01

    Effects of β-carotene on the oxidative stability of chlorophyll or riboflavin photosensitized oil-in-water (O/W) emulsions were determined by analysing the depleted headspace oxygen content, lipid hydroperoxides, fluorescence intensity, and headspace volatiles. As the concentration of β-carotene increased from 0 to 10, 100, and 1000 μM, the oxidative stability of samples containing chlorophylls decreased in a concentration-dependent manner under light, indicating that β-carotene acted as a prooxidant. However, in riboflavin photosensitized O/W emulsions, 100 and 1000 μM β-carotene inhibited lipid oxidation. Although β-carotene protected both photosensitisers in O/W emulsions, β-carotene displayed antioxidative or prooxidative properties, which depended on the polarity of the photosensitisers. The development of t-2-heptenal and 1-octen-3-ol increased greatly in chlorophyll sensitised O/W emulsions with an increase in β-carotene concentration, implying that more singlet oxygen oxidation occurred due to the higher levels of remaining chlorophylls. However, the content of t-2-heptenal and 1-octen-3-ol in the riboflavin sensitised O/W emulsions was not significantly correlated with the β-carotene concentration, which indicates that β-carotene in the lipid particles effectively quenched singlet oxygen. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Elucidation of Genetic Backgrounds Necessary for Chlorophyll a Biosynthesis Toward Artificial Creation of Oxygenic Photosynthesis

    Science.gov (United States)

    Tsukatani, Yusuke; Masuda, Shinji

    2015-09-01

    We succeeded to create the genetically modified purple photosynthetic bacterium capable of synthesizing chlorophyll a. The results indicate that not only chlorophyll synthase, but also an enzyme for galactolipid synthesis and reaction center proteins are required for accumulating chlorophyll a.

  17. Flow cytometry, fluorescent probes, and flashing bacteria

    NARCIS (Netherlands)

    Bunthof, C.J.

    2002-01-01


    Key words: fluorescent probes, flow cytometry, CSLM, viability, survival, microbial physiology, lactic acid bacteria, Lactococcus lactis , Lactobacillus plantarum , cheese, milk,

  18. Relationship between Photosynthesis and Chlorophyll Content during Leaf Senescence of Rice Seedlings

    OpenAIRE

    Mariko, Kura-Hotta; Kazuhiko, Satoh; Sakae, Katoh; Department of Pure and Applied Sciences, College of Arts and Sciences

    1987-01-01

    Photosynthetic oxygen evolution, chlorophyll contents and chlorophyll a/b ratios of 3rd to 6th leaves of rice seedlings were measured to examine whether or not inactivation of photosynthesis during senescence is related to loss of chlorophyll. Photosynthetic activity decreased more rapidly than chlorophyll content during leaf senescence; as a result, the lower the leaf position, the lower was the rate of oxygen evolution determined on the basis of chlorophyll. Chlorophyll a/b ratio also decre...

  19. Observation of Climacteric-Like Behavior of Citrus Leaves Using Fluorescence Spectroscopy

    Directory of Open Access Journals (Sweden)

    Caio B. Wetterich

    2014-01-01

    Full Text Available Observation of climacteric-like behavior in citrus leaves depends on the detection of ethylene. However, such detection requires a gas chromatographer and complex sample preparation procedures. In this work, fluorescence spectroscopy was investigated as a diagnostic technique for climacteric-like behavior in citrus leaves. Our results indicate that the chlorophyll fluorescence presents a time evolution consistent with the ethylene evolution. Therefore, fluorescence spectroscopy may be used to observe the climacteric-like behavior in citrus leaves.

  20. LBA-ECO LC-07 Amazon Floodplain Lake Chlorophyll from MODIS, Para, Brazil: 2002-2003

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains chlorophyll concentration maps of the Amazon River floodplain region from Parintins (Amazonas) to Almeirim (Para). These chlorophyll...

  1. LBA-ECO LC-07 Amazon Floodplain Lake Chlorophyll from MODIS, Para, Brazil: 2002-2003

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains chlorophyll concentration maps of the Amazon River floodplain region from Parintins (Amazonas) to Almeirim (Para). These chlorophyll fraction...

  2. Regional ocean-colour chlorophyll algorithms for the Red Sea

    KAUST Repository

    Brewin, Robert J.W.

    2015-05-18

    The Red Sea is a semi-enclosed tropical marine ecosystem that stretches from the Gulf of Suez and Gulf of Aqaba in the north, to the Gulf of Aden in the south. Despite its ecological and economic importance, its biological environment is relatively unexplored. Satellite ocean-colour estimates of chlorophyll concentration (an index of phytoplankton biomass) offer an observational platform to monitor the health of the Red Sea. However, little is known about the optical properties of the region. In this paper, we investigate the optical properties of the Red Sea in the context of satellite ocean-colour estimates of chlorophyll concentration. Making use of a new merged ocean-colour product, from the European Space Agency (ESA) Climate Change Initiative, and in situ data in the region, we test the performance of a series of ocean-colour chlorophyll algorithms. We find that standard algorithms systematically overestimate chlorophyll when compared with the in situ data. To investigate this bias we develop an ocean-colour model for the Red Sea, parameterised to data collected during the Tara Oceans expedition, that estimates remote-sensing reflectance as a function of chlorophyll concentration. We used the Red Sea model to tune the standard chlorophyll algorithms and the overestimation in chlorophyll originally observed was corrected. Results suggest that the overestimation was likely due to an excess of CDOM absorption per unit chlorophyll in the Red Sea when compared with average global conditions. However, we recognise that additional information is required to test the influence of other potential sources of the overestimation, such as aeolian dust, and we discuss uncertainties in the datasets used. We present a series of regional chlorophyll algorithms for the Red Sea, designed for a suite of ocean-colour sensors, that may be used for further testing.

  3. Validation of MODIS FLH and In Situ Chlorophyll a from Tampa Bay, Florida (USA)

    Science.gov (United States)

    Fischer, Andrew; MorenoMadrinan, Max J.

    2012-01-01

    Satellite observation of phytoplankton concentration or chlorophyll-a (chla) is an important characteristic, critically integral to monitoring coastal water quality. However, the optical properties of estuarine and coastal waters are highly variable and complex and pose a great challenge for accurate analysis. Constituents such as suspended solids and dissolved organic matter and the overlapping and uncorrelated absorptions in the blue region of the spectrum renders the blue-green ratio algorithms for estimating chl-a inaccurate. Measurement of suninduced chlorophyll fluorescence, on the other hand, which utilizes the near infrared portion of the electromagnetic spectrum may, provide a better estimate of phytoplankton concentrations. While modelling and laboratory studies have illustrated both the utility and limitations of satellite algorithms based on the sun induced chlorophyll fluorescence signal, few have examined the empirical validity of these algorithms or compared their accuracy against bluegreen ratio algorithms . In an unprecedented analysis using a long term (2003-2011) in situ monitoring data set from Tampa Bay, Florida (USA), we assess the validity of the FLH product from the Moderate Resolution Imaging Spectrometer against a suite of water quality parameters taken in a variety of conditions throughout this large optically complex estuarine system. . Overall, the results show a 106% increase in the validity of chla concentration estimation using FLH over the standard chla estimate from the blue-green OC3M algorithm. Additionally, a systematic analysis of sampling sites throughout the bay is undertaken to understand how the FLH product responds to varying conditions in the estuary and correlations are conducted to see how the relationships between satellite FLH and in situ chlorophyll-a change with depth, distance from shore, from structures like bridges, and nutrient concentrations and turbidity. Such analysis illustrates that the correlations between

  4. Photogeneration of charges in microcrystalline chlorophyll a

    Energy Technology Data Exchange (ETDEWEB)

    Kassi, Hassan [Scientech R and D, Inc., 2200 Rue Didbec S., Bureau 203, Trois-Rivieres, Trois-Rivieres, QC, G8Z 4H1 (Canada); Barazzouk, Said, E-mail: barazzos@uqtr.c [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada); Brullemans, Marc [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada); Leblanc, Roger M. [Department of Chemistry, University of Miami, P.O. Box 249118, Coral Gables, FL 33124-0431 (United States); Hotchandani, Surat [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada)

    2010-07-01

    The electric-field and temperature dependence of hole photogeneration in chlorophyll a (Chla) have been analyzed in terms of electric-field assisted thermal dissociation of charge pairs based on Onsager theory. An excellent agreement between the experimental and theoretical values of the slope-to-intercept ratio, S/I, for the plot of photogeneration efficiency vs. electric field at low field strengths provides a proof for the applicability of the Onsager approach to the photogeneration of charges in Chla. A value of 19 nm has been obtained for Coulomb capture radius, r{sub c}, from S/I. From the temperature dependence of photogeneration, the initial separation, r{sub 0}, of photogenerated electron-hole has been evaluated, and has a value of 1.24 nm. This smaller r{sub 0} compared to r{sub c} leads to a feeble dissociation probability of electron-hole pairs into free carriers, and may, among other factors, explain the low power conversion efficiencies of Chla photovoltaic cells.

  5. Controlling effects of mesoscale eddies on thermohaline structure and in situ chlorophyll distribution in the western North Pacific

    Science.gov (United States)

    Gao, Wei; Wang, Zhenyan; Zhang, Kainan

    2017-11-01

    Based on the conductivity, temperature and depth (CTD) data collected at 93 hydrographic stations during a marine cruise and on contemporary satellite altimeter observations, a series of eddies have been observed passing over the stratified upper water of the Parece Vela Basin. The results from hydrographic measurements and in situ chlorophyll fluorescence measurements have revealed that these eddies exerted significant controlling effects on the thermohaline structure and chlorophyll distribution, especially on the prevalent subsurface chlorophyll maximum layer (SCML). Based on these observations and particulate beam attenuation coefficient (cp) data, the in situ phytoplankton bloom around the pycnocline can be largely attributable to the formation of a well-developed SCML in the studied system. The uplift of the cold subsurface water within the cyclone, shoaling the pycnocline to a shallower layer, resulted in a low-temperature anomaly and different salinity anomalies at different depths. This uplift in the cyclone further caused the SCML to appear at a shallower depth with a higher in situ chlorophyll concentration than that in the normal domain. Conversely, the sinking of the warm surface water to the subsurface layer within the anticyclone depressed the pycnocline to a deeper layer and generated a high-temperature anomaly and opposite salinity anomalies compared with the cyclone. The sinking of the pycnocline within the anticyclone considerably influenced the characteristics of the SCML, which had a deeper depth and a lower in situ chlorophyll concentration than that of the normal sea. This study contributes rare quasi-synchronous CTD observations capturing mesoscale eddies and provides valuable descriptions of the variations in the SCML under the influence of mesoscale eddies based on in situ optical measurements from the seldom-discussed western North Pacific.

  6. Changes in the fluorescence of the Caribbean coral Montastraea faveolata during heat-induced bleaching

    Science.gov (United States)

    Zawada, David G.; Jaffe, J.S.

    2003-01-01

    In order to evaluate the response of commonly occurring green and orange fluorescent host-based pigments, a thermal stress experiment was performed on specimens of the Caribbean coral Montastraea faveolata. Seven paired samples were collected from a small oceanic reef near Lee Stocking Island in the Bahamas. Seven of the fourteen corals were subjected to elevated temperatures for 28 d, followed by a recovery period lasting 53 d. Throughout the experiment, high-resolution (~400 µm pixel-1) multispectral images of induced fluorescence were recorded at wavelengths corresponding to the green and orange host pigments, plus chlorophyll. These images revealed that the fluorescence of both host pigments was concentrated at polyp centers and declined by 70–90% in regions between polyps. Chlorophyll fluorescence, however, was distributed almost uniformly across the entire coral surface, but with decreases of 10–30% around polyp centers. A normalized difference ratio between the green and orange pigments (GO ratio) was developed to facilitate comparison with chlorophyll fluorescence as a bleaching indicator. Analysis showed a high correspondence between a sustained GO ratio of less than zero and the death of corals. Finally, this ratio was resistant to contamination from other sources of chlorophyll fluorescence, such as filamentous algae.

  7. Assessment of water pollution by airborne measurement of chlorophyll

    Science.gov (United States)

    Arvesen, J. C.; Weaver, E. C.; Millard, J. P.

    1972-01-01

    Remote measurement of chlorophyll concentrations to determine extent of water pollution is discussed. Construction and operation of radiometer to provide measurement capability are explained. Diagram of equipment is provided.

  8. Relationship between chlorophyll-a and column primary production

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.; Bhargava, R.M.S.

    Relationship between surface chlorophyll a and column primary production has been established to help in estimating the latter more quickly and accurately. The equation derived is Primary Production, y = 0.54 Ln Chl a - 0.6. The relationship...

  9. Chlorophyll destruction in the presence of bisulfite. [Spinach oleracea

    Energy Technology Data Exchange (ETDEWEB)

    Peiser, G.; Yang, S.F.

    1985-01-01

    Chlorophyll extracted from Spinacia oleracea leaves as well as purified chlorophyll a in ethanolic solutions (pH 4) was rapidly destroyed, as measured by a decrease in absorbance, in the presence of sodium bisulfite, oxygen and light. Omission of sodium bisulfite, oxygen or light resulted in negligible destruction. The light requirement could be partially substituted by addition of manganous sulfate and destruction was further stimulated in the presence of linoleic acid. Hydroquinone, a free radical scavenger, inhibited both light and Mn/sup 2 +/-mediated (dark) destruction. These results suggest that free radicals produced during the aerobic oxidation of bisulfite are involved in the destruction of chlorophyll. When /sub 35/S-bisulfite was used, two labeled degradation products of chlorophyll were observed.

  10. Effect of immersion systems on chlorophyll contents in micro ...

    African Journals Online (AJOL)

    Basrai variety) an efficient micro-propagation protocol was developed by using micro-stem cutting, as an explant. The maximum numbers of plantlets with higher chlorophyll and lower carotenoid contents were observed, which developed through ...

  11. Fluorescence microscopy.

    Science.gov (United States)

    Sanderson, Michael J; Smith, Ian; Parker, Ian; Bootman, Martin D

    2014-10-01

    Fluorescence microscopy is a major tool with which to monitor cell physiology. Although the concepts of fluorescence and its optical separation using filters remain similar, microscope design varies with the aim of increasing image contrast and spatial resolution. The basics of wide-field microscopy are outlined to emphasize the selection, advantages, and correct use of laser scanning confocal microscopy, two-photon microscopy, scanning disk confocal microscopy, total internal reflection, and super-resolution microscopy. In addition, the principles of how these microscopes form images are reviewed to appreciate their capabilities, limitations, and constraints for operation. © 2014 Cold Spring Harbor Laboratory Press.

  12. Spectral Dependence of Chlorophyll Biosynthesis Pathways in Plant Leaves.

    Science.gov (United States)

    Belyaeva, O B; Litvin, F F

    2015-12-01

    This review covers studies on the dependence of chlorophyll photobiosynthesis reactions from protochlorophyllide on the spectral composition of actinic light. A general scheme of the reaction sequence for the photochemical stage in chlorophyll biosynthesis for etiolated plant leaves is presented. Comparative analysis of the data shows that the use of light with varied wavelengths for etiolated plant illumination reveals parallel transformation pathways of different protochlorophyllide forms into chlorophyllide, including a pathway for early photosystem II reaction center P-680 pigment formation.

  13. Estimating chlorophyll content from Eucalyptus dunnii leaves by reflectance values

    Directory of Open Access Journals (Sweden)

    João Alexandre Lopes Dranski

    2016-06-01

    Full Text Available This study aimed to estimate photosynthetic pigments contents from leaves of Eucalyptus dunni Maiden based on values of reflectance spectra of red, green and blue colors obtained with a digital color analyzer. We collected fifty leaves from the lower third of the crown of twenty trees including young as well as mature leaves. From each leaf an area of 14 cm2 of the leaf blade was cut in which we measured reflectance values on the red, green and blue spectra with a portable digital colorimeter, obtained relative index of chlorophyll with a SPAD – 502 and determined the content of the chlorophyll a, b, and a + b by classic method of solvent extraction. We submitted the data to multiple linear regression and nonlinear analysis at 5% of error probability. It was evaluated the occurrence of multicollinearity. The negative exponential model resulted in good fit when data from red spectrum was used for chlorophyll a, green spectrum for chlorophyll b and a + b, making possible correlation coefficients between the estimated values and the extracted above 0.85. Except for the chlorophyll a content, the accuracy in estimates of photosynthetic pigments were higher than estimated by the chlorophyll meter, even with linearity between methods. Therefore, it is possible to estimate photosynthetic pigments on E. dunni leaves through values of red and green wavelengths from a digital color analyser.

  14. Chlorophylls and Phycoerythrins as Markers of Environmental Forcings Including Cyclone Erica Effect (March 2003 on Phytoplankton in the Southwest Lagoon of New Caledonia and Oceanic Adjacent Area

    Directory of Open Access Journals (Sweden)

    J. Neveux

    2009-01-01

    Full Text Available Spatio-temporal variations of chlorophylls and phycoerythrins, inferred by spectrofluorometric methods, were studied from April 2002 to June 2003 in the southwest lagoon and oceanic waters of New Caledonia. Trade winds blew 75% of the time and appeared as the main factor influencing surface Tchla (sum of monovinyl- and divinyl-chlorophyll a variations in the ocean, near the barrier reef. Lagoon and oceanic waters differed in the composition of picoplanktonic cyanobacteria with a relative dominance of Prochlorococcus and high-phycourobilin Synechococcus in the ocean, and a relative dominance of high-phycoerythrobilin Synechococcus in the lagoon. Main pigment variations in the lagoon were associated with cyclone Erica in March 2003 and showed a 5-6 fold Tchla increase around Nouméa. The cyclone stimulated mainly diatom growth as indicated by the high chlorophyll (c1+c2/chlorophyll a ratio and by the lowest values for the other pigment ratios. The relative importance of divinyl-chlorophyll a concentration and fluorescence excitation spectra of phycoerythrins appeared as useful tools for characterizing lagoon-ocean exchanges.

  15. Response of Chlorophyll, Relative Water Content and Protein Percentage of Safflower Leaves to Salinity and Foliar Calcium, Potassium and Magnesium Applications

    Directory of Open Access Journals (Sweden)

    Mahmood Attarzadeh

    2016-03-01

    Full Text Available To study the effect of Ca, K, and Mn foliar spray on chlorophyll and relative water contents of safflower (cv. Padideh leaves under salinity condition a factorial experiment based on randomized complete block design with three replications was conducted at Vali-e-Asr University Greenhouse in 2011. Factors were salinity with four levels: 0, 500, 1000, and 1500 mg NaCl kg -1, and foliar spraying of plants with four levels: distilled water, 10 mM CaNo3, 10 mM K2HPO4 and 1 mM MnSo4. Spraying were applied two weeks after emergence and continued every 2 weeks. Results showed that 1500 mg NaCl reduced SPAD value, leaf chlorophyll fluorescence and relative water content. However, increasing salinity induced higher leaf water saturation. Foliar spraying of plants with MnSO4, K2HPO4 and CaNo3 nutrients, also reduced SPAD value. Foliar application of plants with Ca(NO32 increased leaf protein in 500 mg NaCl and without salinity. Application of MnSo4 increased chlorophyll b, a+b and also chlorophyll a (in 500 mg NaCl. Thus, in respect to the positive role of calcium and manganese in the production and preservation of chlorophyll and protein, foliar spray application can be a suitable strategy to reduce crop losses under salinity conditions.

  16. Evaluation of nitrogen status and total chlorophyll in longkong (Aglaia dookkoo Griff. leaves under water stress using a chlorophyll meter

    Directory of Open Access Journals (Sweden)

    Sdoodee, S.

    2005-07-01

    Full Text Available A chlorophyll meter (SPAD-502 was used to assess nitrogen status and total chlorophyll in longkong leaves, leaves from twelve of 10-year-old trees grown in the experimental plot at Prince of Songkla University, Songkhla province. The relationship between SPAD-502 meter reading and nitrogen status and total chlorophyll content analyzed in the laboratory was evaluated during 8 months (May-December 2003. It was found that the trend of the relationships in each month was similar. There was no significant differenceamong regression linears of all months. The data of 8 months showed that SPAD-reading and nitrogen content, and SPAD-reading and total chlorophyll content were related in a positive manner. They were Y = 0.19X+10.10, r = 0.76** (n = 240, and Y = 0.43X-7.89, r = 0.79** (n = 400, respectively. The SPAD-502 was then used to assess total nitrogen and total chlorophyll content during imposed water stress. Fifteen 4-yearold plants were grown in pots (each pot containing 50 kg soil volume. The experiment was arranged in acompletely randomized design with 3 treatments: (1 daily watering (2 once watering on day 7 (3 no watering with 5 replications during 14 days of the experimental period. Measurements showed a continuous decrease of SPAD-reading in the treatment of no watering. On day 14, a significant difference of SPAD- reading values between the treatment of daily watering and no watering was found. Then, the values of nitrogen content and total chlorophyll were assessed by using the linear regression equations. From the result, it is suggested that the measurement by chlorophyll meter is a rapid technique for the evaluation of total chlorophyll and nitrogen status in longkong leaves during water stress.

  17. Photoactive nanocomplex formed from chlorophyll assembly on TMA-coated iron oxide nanoparticles

    Science.gov (United States)

    Barbaros, Sibel; Meray, Zeynep; Tecim, Tuğba; Genç, Rükan

    2016-07-01

    In this study, hierarchical self-assembly of photocatalytic nanodisks through non-covalent interactions between spinach-extracted chlorophyll molecules and trimethylammonium hydroxide-coated magnetic iron oxide nanoparticles was discussed. Combination of chlorophyll molecules with iron oxide nanoparticles generated an alteration in light absorption at both visible and near-IR region with accompanying enhancement in fluorescence emission. Further, photocatalytic role of resulting molecular assembly was studied by means of the photoinduced degradation of methylene blue dye under UV light and direct sun irradiation at neutral pH. In order to enhance the long-term stability of the hybrid nanocatalyst, commercially available cellulose membrane was used as a support and magnetic recovery and reusability was achieved where the nanocatalyst retained more than 90 % of its efficiency even after four cycles. This simple strategy could initiate the development of new materials for wastewater treatment including membrane-based technologies. On the other hand, their sunlight-induced photocatalytic activity could easily be conducted to dye-synthesized solar cells or their enhanced photoluminescence can provide a strong basis for future bioimaging tools.

  18. Photoactive nanocomplex formed from chlorophyll assembly on TMA-coated iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Barbaros, Sibel; Meray, Zeynep; Tecim, Tuğba; Genç, Rükan, E-mail: rukangnc@gmail.com [Mersin University, Functional Nanomaterials Laboratory, Chemical Engineering Department, Engineering Faculty (Turkey)

    2016-07-15

    In this study, hierarchical self-assembly of photocatalytic nanodisks through non-covalent interactions between spinach-extracted chlorophyll molecules and trimethylammonium hydroxide-coated magnetic iron oxide nanoparticles was discussed. Combination of chlorophyll molecules with iron oxide nanoparticles generated an alteration in light absorption at both visible and near-IR region with accompanying enhancement in fluorescence emission. Further, photocatalytic role of resulting molecular assembly was studied by means of the photoinduced degradation of methylene blue dye under UV light and direct sun irradiation at neutral pH. In order to enhance the long-term stability of the hybrid nanocatalyst, commercially available cellulose membrane was used as a support and magnetic recovery and reusability was achieved where the nanocatalyst retained more than 90 % of its efficiency even after four cycles. This simple strategy could initiate the development of new materials for wastewater treatment including membrane-based technologies. On the other hand, their sunlight-induced photocatalytic activity could easily be conducted to dye-synthesized solar cells or their enhanced photoluminescence can provide a strong basis for future bioimaging tools.Graphical Abstract.

  19. Global convergence of maixmum light use efficiency using fraction of PAR absorbed by chlorophyll

    Science.gov (United States)

    Zhang, Y.; Xiao, X.; Cescatti, A.; Wolf, S.; Wu, J.; Wu, X.; Gioli, B.; Wohlfahrt, G.; Zhou, S.; Steinbrecher, R.; Gough, C. M.

    2016-12-01

    The efficiency that plants utilize light for photosynthesis has been long established and been used for simple light use efficiency (LUE) models to estimate gross primary production (GPP) from site level to global scales. However, the LUE can be defined at different scales which cause a large variation of maximum LUE values across different models and ecosystem types. Here we use solar-induced chlorophyll fluorescence (SIF) as a proxy of photosynthetically active radiation (PAR) absorbed by chlorophyll (APARchl) and derived an estimation of fraction of APARchl (fPARchl) from four remote sensing based optical vegetation activity indicators (OVAIs). By comparing this fPARchl estimation with eddy flux based GPP from 136 sites, we found that the maximum daily LUE tends to converge to a common value ignorance of the biome types. The seasonal variation of LUEPAR (GPP/PAR) in tropical forest where little environmental limits presents can also be tracked by the change of fPARchl. This global convergence can be used to build simple models to estimate GPP and to constrain process-based models using satellite observations.

  20. Chlorophyll thermofluorescence and thermoluminescence as complementary tools for the study of temperature stress in plants.

    Science.gov (United States)

    Ducruet, Jean-Marc; Peeva, Violeta; Havaux, Michel

    2007-01-01

    The photosynthetic apparatus, especially the electron transport chain imbedded in the thylakoid membrane, is one of the main targets of cold and heat stress in plants. Prompt and delayed fluorescence emission originating from photosystem II have been used, most often separately, to monitor the changes induced in the photosynthetic membranes during progressive warming or cooling of a leaf sample. Thermofluorescence of F (0) and F (M) informs on the effects of heat on the chlorophyll antennae and the photochemical centers, thermoluminescence on the stabilization and movements of charges and Delayed Light Emission on the permeability of the thylakoid membranes to protons and ions. Considered together and operated simultaneously, these techniques constitute a powerful tool to characterize the effect of thermal stress on intact photosynthetic systems and to understand the mechanisms of constitutive or induced tolerance to temperature stresses.

  1. HPLC Analysis of Chlorophyll a, Chlorophyll b, and Beta-Carotene in Collard Greens: A Project for a Problem-Oriented Laboratory Course.

    Science.gov (United States)

    Silveira, Augustine, Jr.; And Others

    1984-01-01

    High performance liquid chromatography (HPLC) is used to separate and quantitate beta-carotene, chlorophyll a, and chlorophyll b originating from collard greens. Experimental procedures used and typical results obtained are discussed. (JN)

  2. Lichens survive in space: results from the 2005 LICHENS experiment.

    Science.gov (United States)

    Sancho, Leopoldo G; de la Torre, Rosa; Horneck, Gerda; Ascaso, Carmen; de Los Rios, Asunción; Pintado, Ana; Wierzchos, J; Schuster, M

    2007-06-01

    This experiment was aimed at establishing, for the first time, the survival capability of lichens exposed to space conditions. In particular, the damaging effect of various wavelengths of extraterrestrial solar UV radiation was studied. The lichens used were the bipolar species Rhizocarpon geographicum and Xanthoria elegans, which were collected above 2000 m in the mountains of central Spain and as endolithic communities inhabiting granites in the Antarctic Dry Valleys. Lichens were exposed to space in the BIOPAN-5 facility of the European Space Agency; BIOPAN-5 is located on the outer shell of the Earth-orbiting FOTON-M2 Russian satellite. The lichen samples were launched from Baikonur by a Soyuz rocket on May 31, 2005, and were returned to Earth after 16 days in space, at which time they were tested for survival. Chlorophyll fluorescence was used for the measurement of photosynthetic parameters. Scanning electron microscopy in back-scattered mode, low temperature scanning electron microscopy, and transmission electron microscopy were used to study the organization and composition of both symbionts. Confocal laser scanning microscopy, in combination with the use of specific fluorescent probes, allowed for the assessment of the physiological state of the cells. All exposed lichens, regardless of the optical filters used, showed nearly the same photosynthetic activity after the flight as measured before the flight. Likewise, the multimicroscopy approach revealed no detectable ultrastructural changes in most of the algal and fungal cells of the lichen thalli, though a greater proportion of cells in the flight samples had compromised membranes, as revealed by the LIVE/DEAD BacLight Bacterial Viability Kit. These findings indicate that most lichenized fungal and algal cells can survive in space after full exposure to massive UV and cosmic radiation, conditions proven to be lethal to bacteria and other microorganisms. The lichen upper cortex seems to provide adequate

  3. Lichens Survive in Space: Results from the 2005 LICHENS Experiment

    Science.gov (United States)

    Sancho, Leopoldo G.; de la Torre, Rosa; Horneck, Gerda; Ascaso, Carmen; de los Rios, Asunción; Pintado, Ana; Wierzchos, J.; Schuster, M.

    2007-06-01

    This experiment was aimed at establishing, for the first time, the survival capability of lichens exposed to space conditions. In particular, the damaging effect of various wavelengths of extraterrestrial solar UV radiation was studied. The lichens used were the bipolar species Rhizocarpon geographicum and Xanthoria elegans, which were collected above 2000 m in the mountains of central Spain and as endolithic communities inhabiting granites in the Antarctic Dry Valleys. Lichens were exposed to space in the BIOPAN-5 facility of the European Space Agency; BIOPAN-5 is located on the outer shell of the Earth-orbiting FOTON-M2 Russian satellite. The lichen samples were launched from Baikonur by a Soyuz rocket on May 31, 2005, and were returned to Earth after 16 days in space, at which time they were tested for survival. Chlorophyll fluorescence was used for the measurement of photosynthetic parameters. Scanning electron microscopy in back-scattered mode, low temperature scanning electron microscopy, and transmission electron microscopy were used to study the organization and composition of both symbionts. Confocal laser scanning microscopy, in combination with the use of specific fluorescent probes, allowed for the assessment of the physiological state of the cells. All exposed lichens, regardless of the optical filters used, showed nearly the same photosynthetic activity after the flight as measured before the flight. Likewise, the multimicroscopy approach revealed no detectable ultrastructural changes in most of the algal and fungal cells of the lichen thalli, though a greater proportion of cells in the flight samples had compromised membranes, as revealed by the LIVE/DEAD BacLight Bacterial Viability Kit. These findings indicate that most lichenized fungal and algal cells can survive in space after full exposure to massive UV and cosmic radiation, conditions proven to be lethal to bacteria and other microorganisms. The lichen upper cortex seems to provide adequate

  4. Chlorophyll a is a favorable substrate for Chlamydomonas Mg-dechelatase encoded by STAY-GREEN.

    Science.gov (United States)

    Matsuda, Kaori; Shimoda, Yousuke; Tanaka, Ayumi; Ito, Hisashi

    2016-12-01

    Mg removal from chlorophyll by Mg-dechelatase is the first step of chlorophyll degradation. Recent studies showed that in Arabidopsis, Stay Green (SGR) encodes Mg-dechelatase. Though the Escherichia coli expression system is advantageous for investigating the properties of Mg-dechelatase, Arabidopsis Mg-dechelatase is not successfully expressed in E. coli. Chlamydomonas reinhardtii SGR (CrSGR) has a long, hydrophilic tail, suggesting that active CrSGR can be expressed in E. coli. After the incubation of chlorophyll a with CrSGR expressed in E. coli, pheophytin a accumulated, indicating that active CrSGR was expressed in E. coli. Substrate specificity of CrSGR against chlorophyll b and an intermediate molecule of the chlorophyll b degradation pathway was examined. CrSGR exhibited no activity against chlorophyll b and low activity against 7-hydroxymethyl chlorophyll a, consistent with the fact that chlorophyll b is degraded only after conversion to chlorophyll a. CrSGR exhibited low activity against divinyl chlorophyll a and chlorophyll a', and no activity against chlorophyllide a, protochlorophyll a, chlorophyll c2, and Zn-chlorophyll a. These observations indicate that chlorophyll a is the most favorable substrate for CrSGR. When CrSGR was expressed in Arabidopsis cells, the chlorophyll content decreased, further confirming that SGR has Mg-dechelating activity in chloroplasts. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Three-dimensional fluorescence characteristics of white chrysanthemum flowers

    Science.gov (United States)

    Fan, Yunchang; Li, Yang; Cai, Hongxin; Li, Jing; Miao, Juan; Fu, Dexue; Su, Kun

    2014-09-01

    White chrysanthemum flower is one of the most popular plants found everywhere in China and used as herbs. In the present work, three-dimensional fluorescence technique was used to discriminate species of white chrysanthemum flowers. Parameters affecting extraction efficiency were investigated. Under the optimal conditions, the three-dimensional fluorescence characteristics of three types of white chrysanthemum flowers were obtained. It was found that there were two main fluorescence peaks with remarkable difference in fluorescence intensity, one was corresponding to flavonoids and another was attributed to chlorophyll-like compounds. There were remarkable differences among the contours of the three white chrysanthemum flowers. Further studies showed that the fluorescence intensity ratios of chlorophyll-like compounds to flavonoids had a certain relationship with the species; those for Huai, Hang and Huangshan white chrysanthemum flowers were 6.9-7.4, 18.9-21.4 and 73.6-84.5, respectively. All of the results suggest that three-dimensional fluorescence spectra can be used for the discrimination of white chrysanthemum flowers with the advantages of low cost, ease for operation and intuition.

  6. Chloroplast to chromoplast transition in tomato fruit: spectral confocal microscopy analyses of carotenoids and chlorophylls in isolated plastids and time-lapse recording on intact live tissue.

    Science.gov (United States)

    Egea, Isabel; Bian, Wanping; Barsan, Cristina; Jauneau, Alain; Pech, Jean-Claude; Latché, Alain; Li, Zhengguo; Chervin, Christian

    2011-08-01

    There are several studies suggesting that tomato (Solanum lycopersicum) chromoplasts arise from chloroplasts, but there is still no report showing the fluorescence of both chlorophylls and carotenoids in an intermediate plastid, and no video showing this transition phase. Pigment fluorescence within individual plastids, isolated from tomato fruit using sucrose gradients, was observed at different ripening stages, and an in situ real-time recording of pigment fluorescence was performed on live tomato fruit slices. At the mature green and red stages, homogenous fractions of chloroplasts and chromoplasts were obtained, respectively. At the breaker stage, spectral confocal microscopy showed that intermediate plastids contained both chlorophylls and carotenoids. Furthermore, an in situ real-time recording (a) showed that the chloroplast to chromoplast transition was synchronous for all plastids of a single cell; and (b) confirmed that all chromoplasts derived from pre-existing chloroplasts. These results give details of the early steps of tomato chromoplast biogenesis from chloroplasts, with the formation of intermediate plastids containing both carotenoids and chlorophylls. They provide information at the sub-cellular level on the synchronism of plastid transition and pigment changes.

  7. The 1-Hz fluorometer: A new approach to fast and sensitive long-term studies of active chlorophyll and environmental influences

    Science.gov (United States)

    Moldaenke, C.; Vanselow, K. H.; Hansen, U.-P.

    1995-03-01

    A new instrument for environmental monitoring, called at 1-Hz fluorometer, provides two modes of application. First, it enables a quantitative determination of algal concentrations down to 20 ng/l. Second, it can be used as a biosensor for changes in environmental conditions. The distinction between the signals from living chlorophyll-containing algae and other fluorescent material is achieved by using two modulated light-sources resulting in a mean fluence rate of 200 μE. The measuring light induces changes in chlorophyll fluorescence (yield) with a frequency of 1 kHz, and the actinic light modulates the redox state of the quenchers of PS II with a frequency of 1 Hz. This leads to a modulation of the yield which is detected by two phase-sensitive rectifiers (double correlation). Measurements from different sites in a river, and in the Baltic and North Seas, show that correction by the built-in simultaneously-measured attenuation is necessary in order to obtain values which are identical with those determined by a photometric analysis (Uvikon 860). This applies if the transmission becomes less than about 95%. Suspensions of Dunaliella salina exposed to ammonia and phosphate were used for illustrating the usage for environmental monitoring. It is shown that this system can measure changes in the chlorophyll fluorescence of living algae caused by changes in concentration of ammonia down to 1 μg/l and of phosphate down to 10 μg/l.

  8. Hole burning study of cyanobacterial Photosystem II complexes differing in the content of small putative chlorophyll-binding proteins

    Energy Technology Data Exchange (ETDEWEB)

    Dedic, R. E-mail: roman@kchf-43.karlov.mff.cuni.cz; Promnares, K.; Psencik, J.; Svoboda, A.; Korinek, M.; Tichy, M.; Komenda, J.; Funk, C.; Hala, J

    2004-05-01

    This contribution presents low-temperature absorption, both broad-band and site-selective excited fluorescence, and persistent hole burning spectra of Photosystem II complexes from the Photosystem I-lacking strains of the cyanobacterium Synechocystis sp. PCC 6803 differing in the content of small putative chlorophyll-binding proteins (Scps). These proteins are homologous to light-harvesting complex of higher plants and may bind pigments. The excited state lifetimes of the complexes were determined from zero-phonon hole widths extrapolated to zero-burning dose. The area and spectral position of a phonon side-band with respect to the zero-phonon hole provided additional information concerning chlorophyll-protein coupling and the Stokes shift. Decrease of three absorption subbands at (670.0, 672.9, and 675.7 nm) in the Photosystem II isolated from the strain lacking ScpC and ScpD is in agreement with a hypothesis about the role of Scps in the chlorophyll binding. In addition, narrowing of the zero-phonon hole in Photosystem II without both Scps indicates slowering of the excitation energy transfer which may be explained by the absence of a protective excitation energy quenching related to the presence of Scps.

  9. Delayed fluorescence spectra of intact leaves photoexcited by sunlight measured with a multichannel Fourier-transform chemiluminescence spectrometer

    Science.gov (United States)

    Akita, Saeka; Yano, Ayako; Ishii, Hiroshi; Satoh, Chikahiro; Akai, Nobuyuki; Nakata, Munetaka

    2013-06-01

    Delayed fluorescence spectra of intact leaves of Green pak choi (Brassica rapa var. chinensis) were measured with a multichannel Fourier-transform chemiluminescence spectrometer, which we developed recently. The intact samples, photoexcited by sunlight without artificial light sources, showed delayed fluorescence around 740 nm with a lifetime of ˜6 s. The observed spectra were deconvoluted into two Gaussian bands: the delayed fluorescence from photosystem II and photosystem I complexes. Their relative intensities depended on the chlorophyll concentration, but their wavelengths were unchanged.

  10. Multivariate Analyses of Phytoplankton Pigment Fluorescence from a Freshwater River Network.

    Science.gov (United States)

    Bhattacharya, Ruchi; Osburn, Christopher L

    2017-06-20

    Monitoring phytoplankton classes in river networks is critical to understanding phytoplankton dynamics and to predicting the ecosystem response to changing land-use and seasons. Applicability of phytoplankton fluorescence as a quick and effective ecological monitoring approach is relatively unexplored in freshwater ecosystems. We used multivariate analyses of fluorescence from pigment extracted in 90% acetone to assess the variability in phytoplankton classes, herbivory, and organic matter quality in a freshwater river network. A total of four models developed by the parallel factor analysis (PARAFAC) of fluorescence excitation and emission matrices identified six components: Model 1 (pheophytin-A and chlorophyll-A), Model 2 (chlorophyll-B and chlorophyll-C), Model 3 (pheophytin-B), and Model 4 (pheophytin-C). Redundancy analyses revealed that in the summer, urban and agricultural streams were abundant in chlorophylls, fresh organic matter, and organic nitrogen, whereas in winter, streams were high in phaeopigments. A slow-moving, light-limited wetland stream was an exception as high phaeopigment abundance was observed in both seasons. The PARAFAC components were used to develop a partial least-squares regression-based model (r 2 = 0.53; Nash-Sutcliffe efficiency = 0.5; n = 147) that successfully predicted chlorophyll-A concentrations from an external subset of river water samples (r 2 = 0.41; p phytoplankton dynamics in large river networks.

  11. Optimal leaf positions for chlorophyll meter measurement in rice

    Directory of Open Access Journals (Sweden)

    Zhaofeng eYuan

    2016-05-01

    Full Text Available The Soil Plant Analysis Development (SPAD chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.. A flatbed color scanner was used to map the dynamic chlorophyll distribution and irregular leaf shapes. Calculus algorithm was adopted to estimate the potential positions for SPAD meter measurement along the leaf blade. Data generated by the flatbed color scanner and SPAD meter were analysed simultaneously. The results suggested that a position 2/3 of the distance from the leaf base to the apex (2/3 position could represent the chlorophyll content of the entire leaf blade, as indicated by the relatively low variance of measurements at that positon. SPAD values based on di-positional leaves and the extracted chlorophyll a and b contents were compared. This comparison showed that the 2/3 position on the lower leaves tended to be more sensitive to changes in chlorophyll content. Finally, the 2/3 position and average SPAD values of the fourth fully expanded leaf from the top were compared with leaf nitrogen concentration. The results showed the 2/3 position on that leaf was most suitable for predicting the nitrogen status of rice. Based on these results, we recommend making SPAD measurements at the 2/3 position on the fourth fully expanded leaf from the top. The coupling of dynamic chlorophyll distribution and irregular leaf shapes information can provide a promising approach for the calibration of SPAD meter measurement, which can further benefit the in situ nitrogen management by providing reliable estimation of crops nitrogen nutrition status.

  12. Dissipation of excess excitation energy by drought-induced nonphotochemical quenching in two species of drought-tolerant moss: desiccation-induced acceleration of photosystem II fluorescence decay.

    Science.gov (United States)

    Yamakawa, Hisanori; Itoh, Shigeru

    2013-07-02

    Drought-tolerant mosses survive with their green color intact even after long periods of dehydration that would kill ordinary plants. The mechanism of dissipation of excitation energy under drought stress was studied in two species of drought-tolerant moss, Rhytidium rugosum and Ceratodon purpureus. They showed severe quenching of photosystem II chlorophyll fluorescence (PSII) after being dehydrated in the dark. Quenching was induced by the acceleration of the fluorescence decay rate. This drought-induced nonphotochemical quenching (designated d-NPQ) was fully reversed by rehydration. Global analysis of fluorescence decay at 77 K indicated rapid 46 ps transfer of excitation energy from the 680-690 nm PSII bands to a 710 nm band, and to 740-760 nm bands. The latter bands decayed to the ground state with the same time constant showing the rapid dissipation of excitation energy into heat. The quenching by d-NPQ in dry moss was stronger than that by PSII charge separation or nonphotochemical quenching (NPQ), which operates under hydrating conditions. Drought-tolerant mosses, thus, dissipate excess excitation energy into heat. The d-NPQ mechanism in moss resembles that reported in lichens, suggesting their common origin.

  13. Determination of microphytobenthos PSII quantum efficiency and photosynthetic activity by means of variable chlorophyll fluorescence

    NARCIS (Netherlands)

    Kromkamp, J.C.; Barranguet, C.; Peene, J.

    1998-01-01

    A pulse amplitude modulated fluorometer (PAM) was used to investigate photosynthetic activity of microphytobenthos on an intertidal mudflat. Spectral irradiance measurements indicate that 75% of the signal detectable by the PAM originates in the upper 150 mu m of the sediment. From the

  14. Modern stromatolite phototrophic communities: a comparative study of procaryote and eucaryote phototrophs using variable chlorophyll fluorescence

    NARCIS (Netherlands)

    Perkins, R.G.; Mouget, J.L.; Kromkamp, J.C.; Stolz, J.; Reid, R.P.

    2012-01-01

    Stromatolites are laminated organosedimentary structures formed by microbial communities, principally cyanobacteria although eucaryote phototrophs may also be involved in the construction of modern stromatolites. In this study, productivity and photophysiology of communities from stromatolites

  15. Effects of LEDs on chlorophyll fluorescence and secondary metabolites in Phalaenopsis

    DEFF Research Database (Denmark)

    Ouzounis, T.; Fretté, X.; Rosenqvist, Eva

    2015-01-01

    Light emitting diodes (LEDs) are solid-state semiconductor devices that have been integrated in current greenhouse systems the last decades as they provide the opportunity to control light spectrum. Commercial production of potted orchids under LEDs has increased throughout the world the past...... h per day. The temperature in the greenhouse compartments was set to 24/18°C day/night, respectively. The three light treatments were (1) 40% Blue 60% Red, (2) 100% Red, and (3) 100% White (Control). The plants were harvested before flowering and plant growth was recorded at the end...

  16. Metal-enhanced fluorescence of chlorophylls in light-harvesting complexes coupled to silver nanowires

    Science.gov (United States)

    Twardowska, Magdalena; Kowalska, Dorota; Olejnik, Maria; Maćkowski, Sebastian

    2014-03-01

    We present passive mode locking of a vertical external-cavity surface-emitting laser (VECSEL) in the red spectral range. The gain structure includes 20 compressively strained GaInP quantum wells (QWs), which are arranged in a resonant periodic gain design containing five packages of four quantum wells each. We use tensile strained AlGaInP barriers and cladding layers to compensate the strain introduced by the quantum wells. The semiconductor saturable absorber mirror (SESAM) includes two of the same quantum wells as used in the gain structure, positioned close to the surface. The semiconductor structure is grown by MOVPE in a near-resonant design and coated with a fused silica layer for an overall anti-resonant design. For tight focussing of the laser mode onto the absorber, we use a v-shaped cavity with an overall length of 179mm. Autocorrelation measurements show a FWHM pulse duration below 250 fs with side pulses arising due to the diamond heatspreader bonded onto the gain chip. The laser spectrum consists of a soliton-like part at 664.5 nm and a "continuum" which is also found in autocorrelation measurements perfomed in a Hanbury-Brown and Twiss type setup. An FFT based frequency analysis of the emitted pulse train shows a repetition rate of 836MHz. The SESAM charge carrier dynamics were investigated by pump-probe measurements. We observe a tri-exponential decay with a dominant fast decay time in the range of the pulse duration.

  17. Linking Leaf Chlorophyll Fluorescence Properties to Physiological Responses for Stress Detection in Coastal Plant Species

    Science.gov (United States)

    2007-01-01

    australis (Cav.) Trin. ex Steud. (common reed), Poaceae , is an invasive perennial grass that has formed numerous large colonies, fringing freshwater and...were obtained from a nursery using local seed stock. Seedlings were transplanted into 2-l plastic pots and acclimated for at least 4 weeks prior to...EP, Guntenspergen GR, Brown JJ, Nelson SG (2006) Salt tolerance and osmotic adjustment of Spartina alterniflora ( Poaceae ) and the invasive M

  18. Rethinking Chlorophyll Responses To Stress: Fluorescence and Flectance Remote Sensing in a Coastal Environment

    Science.gov (United States)

    2010-11-15

    of the drought cycle (Table 1), stomata were completely closed, while some level of opening was maintained due Figure 1. Tissue chlorides (top...in other species [8, 24-25]. While net photosynthetic rate declined, stomata were still open under saline conditions, allowing for some gas

  19. Effect of colloidal metals on the induced chlorophyll fluorescence at the different lupin state

    Science.gov (United States)

    Son'ko, R. V.; Starodub, N. F.; Trach, V. V.; Lopat'ko, K. G.

    2013-11-01

    The results of studies about the effects of colloidal solutions of Fe and Zn on the photosynthetic activity of plants of yellow lupine affected by carbonate chlorosis are given. It is shown that the impression of plants by carbonate chlorosis causes a decrease in the efficiency of photosystem II and in result of that the affected plants lag in a weight. Processing plants by the colloidal solutions of iron and zinc creates conditions for improvement of function of the photosynthetic apparatus of plants.

  20. Effects of Water Stress on Photosynthesis and Chlorophyll Fluorescence of the Sugar Beet

    Directory of Open Access Journals (Sweden)

    HAN Kai-hong

    2015-10-01

    Full Text Available To investigate the effect of water stress and rewatering on sugar beet yield and its corresponding photosynthetic parameters, and to provide the basis of water management for the sugar beet fields, pool experiments in an artificial proof canopy were set up to observe changes of beet net photosynthetic rate(Pn, transpiration rate(Tr, water use efficiency(WUE and stomatal limitation (Ls, intercellular CO2 oncentration(Ci, and PSⅡ maximum quantum yield(Fv/Fm. The results indicated that the diurnal variation of Tr and Pn in CK treatment (whole growth period replenishment at different times near "unimodal" type; and water shortage treatments presented "twin peaks" change. Diurnal transpiration capacity(DTC under water stress at sugar accumulation stage reduced by 70.16%~74.81% and diurnal photosynthetic capacity(DPC was 63.48%~69.96% lower than that of CK, while diurnal water use efficiency(WUEd increased by 19.28%~22.39%. Rehydration helped Tr and Pn recovery, but did not reach unstressed levels. Ls changes under extremely dry environment had a midday trough "twin peaks" feature, and Ci was at "double-dip" in consistent with the timing of Ls; Water stress inhibited and inactivated photochemical reaction center of midday PSⅡ. Water stress led to irreversible decrease in the Pn and Tr, and prolonged the Pn inefficient period, which become the important factor of influencing the sugar beet yield.

  1. High throughput screening with chlorophyll fluorescence imaging and its use in crop improvement

    NARCIS (Netherlands)

    Harbinson, J.; Prinzenberg, A.E.; Kruijer, W.T.; Aarts, M.G.M.

    2012-01-01

    Marker assisted plant breeding is a powerful technique for targeted crop improvement in horticulture and agriculture. It depends upon the correlation of desirable phenotypic characteristics with specific genetic markers. This can be determined by statistical models that relate the variation in the

  2. Stink Bug Feeding Induces Fluorescence in Developing Cotton Bolls

    Directory of Open Access Journals (Sweden)

    Toews Michael D

    2011-08-01

    Full Text Available Abstract Background Stink bugs (Hemiptera: Pentatomidae comprise a critically important insect pest complex affecting 12 major crops worldwide including cotton. In the US, stink bug damage to developing cotton bolls causes boll abscission, lint staining, reduced fiber quality, and reduced yields with estimated losses ranging from 10 to 60 million dollars annually. Unfortunately, scouting for stink bug damage in the field is laborious and excessively time consuming. To improve scouting accuracy and efficiency, we investigated fluorescence changes in cotton boll tissues as a result of stink bug feeding. Results Fluorescent imaging under long-wave ultraviolet light showed that stink bug-damaged lint, the inner carpal wall, and the outside of the boll emitted strong blue-green fluorescence in a circular region near the puncture wound, whereas undamaged tissue emissions occurred at different wavelengths; the much weaker emission of undamaged tissue was dominated by chlorophyll fluorescence. We further characterized the optimum emission and excitation spectra to distinguish between stink bug damaged bolls from undamaged bolls. Conclusions The observed characteristic fluorescence peaks associated with stink bug damage give rise to a fluorescence-based method to rapidly distinguish between undamaged and stink bug damaged cotton bolls. Based on the fluorescent fingerprint, we envision a fluorescence reflectance imaging or a fluorescence ratiometric device to assist pest management professionals with rapidly determining the extent of stink bug damage in a cotton field.

  3. Stink bug feeding induces fluorescence in developing cotton bolls.

    Science.gov (United States)

    Xia, Jinjun; Mustafic, Adnan; Toews, Michael D; Haidekker, Mark A

    2011-08-04

    Stink bugs (Hemiptera: Pentatomidae) comprise a critically important insect pest complex affecting 12 major crops worldwide including cotton. In the US, stink bug damage to developing cotton bolls causes boll abscission, lint staining, reduced fiber quality, and reduced yields with estimated losses ranging from 10 to 60 million dollars annually. Unfortunately, scouting for stink bug damage in the field is laborious and excessively time consuming. To improve scouting accuracy and efficiency, we investigated fluorescence changes in cotton boll tissues as a result of stink bug feeding. Fluorescent imaging under long-wave ultraviolet light showed that stink bug-damaged lint, the inner carpal wall, and the outside of the boll emitted strong blue-green fluorescence in a circular region near the puncture wound, whereas undamaged tissue emissions occurred at different wavelengths; the much weaker emission of undamaged tissue was dominated by chlorophyll fluorescence. We further characterized the optimum emission and excitation spectra to distinguish between stink bug damaged bolls from undamaged bolls. The observed characteristic fluorescence peaks associated with stink bug damage give rise to a fluorescence-based method to rapidly distinguish between undamaged and stink bug damaged cotton bolls. Based on the fluorescent fingerprint, we envision a fluorescence reflectance imaging or a fluorescence ratiometric device to assist pest management professionals with rapidly determining the extent of stink bug damage in a cotton field.

  4. Using Optical Sensors on Gliders to Estimate Phytoplankton Carbon Concentrations and Chlorophyll-to-Carbon Ratios in the Southern Ocean

    Directory of Open Access Journals (Sweden)

    Sandy J. Thomalla

    2017-02-01

    Full Text Available One approach to deriving phytoplankton carbon biomass estimates (Cphyto at appropriate scales is through optical products. This study uses a high-resolution glider data set in the Sub-Antarctic Zone (SAZ of the Southern Ocean to compare four different methods of deriving Cphyto from particulate backscattering and fluorescence-derived chlorophyll (chl-a. A comparison of the methods showed that at low (<0.5 mg m−3 chlorophyll concentrations (e.g., early spring and at depth, all four methods produced similar estimates of Cphyto, whereas when chlorophyll concentrations were elevated one method derived higher concentrations of Cphyto than the others. The use of methods derived from particulate backscattering rather than fluorescence can account for cellular adjustments in chl-a:Cphyto that are not driven by biomass alone. A comparison of the glider chl-a:Cphyto ratios from the different optical methods with ratios from laboratory cultures and cruise data found that some optical methods of deriving Cphyto performed better in the SAZ than others and that regionally derived methods may be unsuitable for application to the Southern Ocean. A comparison of the glider chl-a:Cphyto ratios with output from a complex biogeochemical model shows that although a ratio of 0.02 mg chl-a mg C−1 is an acceptable mean for SAZ phytoplankton (in spring-summer, the model misrepresents the seasonal cycle (with decreasing ratios from spring to summer and low sub-seasonal variability. As such, it is recommended that models expand their allowance for variable chl-a:Cphyto ratios that not only account for phytoplankton acclimation to low light conditions in spring but also to higher optimal chl-a:Cphyto ratios with increasing growth rates in summer.

  5. Teaching laser-induced fluorescence of plant leaves

    Science.gov (United States)

    Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

    2016-11-01

    Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll-a, called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll-a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters.

  6. Improved ocean chlorophyll estimate from remote sensed data: The ...

    African Journals Online (AJOL)

    0000

    ocean chlorophyll, expressed the need for further work to be done in order to obtain improved results. One problem faced ... that analysis on primary productivity and management in the ocean environment will be greatly enhanced by this new ... One of the problems faced by the blending method when applied to ocean ...

  7. Effects of copper stress on antioxidative enzymes, chlorophyll and ...

    African Journals Online (AJOL)

    Administrator

    2011-09-05

    Sep 5, 2011 ... Effects of copper stress on antioxidative enzymes, chlorophyll and protein content in Atriplex ... One of the major consequences of Cu toxicity is oxidative stress mediated by increased levels of ..... Mitochondrial alterations, cellular response to oxidative stress and defective degradation of proteins in aging.

  8. Optical teledetection of chlorophyll a in turbid inland waters

    NARCIS (Netherlands)

    Gons, H.J.

    1999-01-01

    Determination of subsurface spectral irradiance reflectance by use of a hand-held spectroradiometer and then estimation of chlorophyll a (Chl-a) concentration facilitate assessment of ecological change in turbid lakes, rivers, and estuaries. The method was applied under widely varying solar

  9. Nodulation, chlorophyll content and nitrogen yield of two woody ...

    African Journals Online (AJOL)

    Two field studies were conducted at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Nigeria between 2000 and 2002 to compare the growth, nodulation, chlorophyll content and nitrogen accumulation of Leucaena leucocephala (Lam) de Wit cv. 28 and Gliricidia sepium (Jacq.) Walp cv. ILG50 at the ...

  10. Leaf Chlorophyll Content and Tuberous Root Yield of Cassava in ...

    African Journals Online (AJOL)

    Two field trials were established in 1996 and 1997 to assess genotypic variability of four cassava (Manihot esculanta) cultivars for adaptability in the inland valley in terms of leaf chlorophyll content and tuberous root yield, using a 4 x 4 Latin square design with four replications arranged along the toposequence.

  11. Covalently stabilized self-assembled chlorophyll nanorods by olefin metathesis.

    Science.gov (United States)

    Sengupta, Sanchita; Würthner, Frank

    2012-06-11

    A new chlorophyll derivative with peripheral olefinic chains has been synthesised and its self-assembly properties have been studied, revealing formation of well-defined nanorods. These nanorods were stabilized and rigidified by olefin metathesis reaction as confirmed by spectroscopic and microscopic methods.

  12. Control of olive oil adulteration with copper-chlorophyll derivatives.

    Science.gov (United States)

    Roca, María; Gallardo-Guerrero, Lourdes; Mínguez-Mosquera, María Isabel; Gandul Rojas, Beatriz

    2010-01-13

    The present work proposes an analytical method able to detect in an adulterated olive oil sample the addition of the copper complexes of chlorophylls (E 141i). The method consists of a pigment extraction in liquid phase and subsequent analysis by HPLC-DAD. The profile of chlorophyll pigments of an olive oil is determined essentially by its content in pheophytins (a and b), but in no case any copper derivative. Different samples of colorant E 141i have been analyzed, the natural coloring additives used to adulterate vegetable oils. The 99.59+/-0.52% of the chlorophyll pigments present in the different samples of E 141i colorant are not those of an olive oil (more than 75% are cupro-derivatives). Thus, the simple detection of one of the compounds in an olive oil indicates adulteration. The major chlorophyll derivative in all the E 141i colorants samples is Cu-pyropheophytin a and its limit of detection (LOD) defined at a signal-to-noise ratio of about 3 was 6.58 ng/g.

  13. Boron, zinc and microtone effects on growth, chlorophyll contents ...

    African Journals Online (AJOL)

    The micronutrient required in minute quantity and their deficiency leads to diminished growth and yield of crops. The effect of soil application of Zinc (Zn), Boron (B) and Microtone (MT) on growth, chlorophyll contents, mineral profile and yield components were investigated in rice at Chakkanwali Reclamation Research ...

  14. Genome-wide examination of chlorophyll metabolic genes in maize ...

    African Journals Online (AJOL)

    Chlorophyll (Chl) is the key pigment involved in photosynthesis. Analysis of the expression pattern of Chl metabolic genes will contribute to our understanding of photosynthesis. Also, the genes coding for Chl metabolism are ideal targets for revealing the evolution relationships of photosynthetic organisms. In this study, we ...

  15. Chlorophyll as a measure of plant health: Agroecological aspects

    Directory of Open Access Journals (Sweden)

    Danijela Pavlović

    2014-03-01

    Full Text Available As photosynthesis is the basic process during which light energy is absorbed and converted into organic matter, the importance of the plant pigment chlorophyll (a and b forms as an intermediary in transformation of the absorbed solar energy and its activity in the process of photosynthesis and synthesis of organic substances in plants are crucial. Therefore, this paper provides an overview of methods for monitoring the optical activity of chlorophyll molecules and methods (non-destructive and destructive for quantification of chlorophyll in plants. These methods are used to estimate the effects of different stress factors (abiotic, biotic and xenobiotic on the efficiency of photosynthesis and bioproductivity, aiming to assess the impact that these limiting factors have on the yield of various cultivars. Also, those methods for analysis of chlorophyll optical activity and/or content are appropriate for assessing the reaction of weed species to different agricultural practices (mineral nutrition, treatment by herbicides, etc. and studies of different aspects of weed ecophysiology and their influence on crop harvest.

  16. Validation of OCM-2 sensor performance in retrieving chlorophyll ...

    Indian Academy of Sciences (India)

    The Chlorophyll and Total Suspended Matter (TSM) data retrieved from Ocean Colour Monitor (OCM-2) onboard Oceansat-2 were tested for the accuracy using in-situ measurements made along the southwest Bay of Bengal coast during cruises and monthly samplings synchronized with satellite overpass from January ...

  17. Improved ocean chlorophyll estimate from remote sensed data: The ...

    African Journals Online (AJOL)

    Gregg and Conkright (2001) who pioneered the use of the blending technique in an attempt to calibrate ocean chlorophyll, expressed the need for further work to be done in order to obtain improved results. One problem faced when using this technique with spatially sparse data, is distortion of the resulting blended field ...

  18. Effect of temperature on accumulation of chlorophylls and leaf ...

    African Journals Online (AJOL)

    The effects of temperature on leaf colour, accumulation of chlorophylls and leaf ultrastructures of an albino tea cultivar 'Xiaxueya' were investigated. The study showed that the shoot albino phenomenon of 'Xiaoxueya' was controlled by temperature. The development of chloroplast from etioplast and the accumulation of ...

  19. Effect of organic and inorganic fertilizer on yield and chlorophyll ...

    African Journals Online (AJOL)

    The effects of amending soil with organic (poultry manure) and inorganic fertilizer on yield and chlorophyll content of maize (Zea mays L.) and sorghum (Sorghum bicolour (L.) Moench) was carried out at the Teaching and Research (T&R) Farm of the Obafemi Awolowo University, (O.A.U.) Ile - Ife, Nigeria. The experiment ...

  20. Antioxidants and chlorophyll content of blanched vegetables stored ...

    African Journals Online (AJOL)

    The fresh leaves of 'Tete' (Amaranthus hybridus) and 'Soko' (Celosia argentea) were blanched and stored in the freezer at the temperature of -10oC±2oC where there was 8hours (day) and 5hours (night) electric power supply to the freezer. The antioxidant (Vitamin C, total phenol and reducing power) and chlorophyll a and ...

  1. Remotely sensed variability of temperature and chlorophyll in the ...

    African Journals Online (AJOL)

    A consistent time-series of daily sea surface temperature (SST) and chlorophyll a concentration images is generated for the period July 1998–June 2003, and a quantitative analysis undertaken. The variability in SST, upwelling and phytoplankton biomass is explored for selected biogeographic regions, with particular focus ...

  2. Chlorophyll meter reading and total nitrogen content applied as ...

    African Journals Online (AJOL)

    The present study was aimed to assess the relationship between the reading of the chlorophyll meter and the total nitrogen (N) content in the leaf in different parts of the crambe plant, depending on the doses of nitrogen applied to the canopy. Randomized block design in a split plot experimental design was used. The plots ...

  3. Chlorophyll meter reading and total nitrogen content applied as ...

    African Journals Online (AJOL)

    Ana Mascarello

    The present study was aimed to assess the relationship between the reading of the chlorophyll meter and the total nitrogen (N) content in the leaf in different parts of the crambe plant, depending on the doses of nitrogen applied to the canopy. Randomized block design in a split-plot experimental design was used. The plots ...

  4. Introduction to fluorescence microscopy.

    Science.gov (United States)

    Ghiran, Ionita C

    2011-01-01

    This chapter is an overview of basic principles of fluorescence microscopy, including a brief history on the invention of this type of microscopy. The chapter highlights important points related to properties of fluorochromes, resolution in fluorescence microscopy, phase contrast and fluorescence, fluorescence filters, construction of a fluorescence microscope, and tips on the correct use of this equipment.

  5. Demonstration of plant fluorescence by imaging technique and Intelligent FluoroSensor

    Science.gov (United States)

    Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

    2015-10-01

    Photosynthesis is a process that converts carbon-dioxide into organic compounds, especially into sugars, using the energy of sunlight. The absorbed light energy is used mainly for photosynthesis initiated at the reaction centers of chlorophyll-protein complexes, but part of it is lost as heat and chlorophyll fluorescence. Therefore, the measurement of the latter can be used to estimate the photosynthetic activity. The basic method, when illuminating intact leaves with strong light after a dark adaptation of at least 20 minutes resulting in a transient change of fluorescence emission of the fluorophore chlorophyll-a called `Kautsky effect', is demonstrated by an imaging setup. The experimental kit includes a high radiant blue LED and a CCD camera (or a human eye) equipped with a red transmittance filter to detect the changing fluorescence radiation. However, for the measurement of several fluorescence parameters, describing the plant physiological processes in detail, the variation of several excitation light sources and an adequate detection method are needed. Several fluorescence induction protocols (e.g. traditional Kautsky, pulse amplitude modulated and excitation kinetic), are realized in the Intelligent FluoroSensor instrument. Using it, students are able to measure different plant fluorescence induction curves, quantitatively determine characteristic parameters and qualitatively interpret the measured signals.

  6. ECOHAB: Tester_P - Gulf of Mexico Chlorophyll - 1998-09 (NODC Accession 0000537)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chlorophyll a is a standard measure for phytoplankton biomass. Routinely, samples for extracted chlorophyll a values are filtered at sea, stored in liquid nitrogen,...

  7. ECOHAB: Tester_P - Gulf of Mexico Chlorophyll - 1998-09 (NODC Accession 0000536)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chlorophyll a is a standard measure for phytoplankton biomass. Routinely, samples for extracted chlorophyll a values are filtered at sea, stored in liquid nitrogen,...

  8. Subsurface chlorophyll maxima in the north-western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.; Aswanikumar, V.

    The depth profiles of phytoplankton pigments in the north-western Bay of Bengal are generally characterizEd. by a subsurface chlorophyll maximum. The occurrence of subsurface chlorophyll maxima is discussed in relation to other information on water...

  9. LBA-ECO LC-07 Amazon Floodplain Lake Chlorophyll from MODIS, Para, Brazil: 2002-2003

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set, LBA-ECO LC-07 Amazon Floodplain Lake Chlorophyll from MODIS, Para, Brazil: 2002-2003, contains chlorophyll concentration maps of the Amazon River...

  10. Atmospheric deposition and surface stratification as controls of contrasting chlorophyll abundance in the North Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Patra, P.K.; DileepKumar, M.; Mahowald, N.; Sarma, V.V.S.S.

    -averages (1997-2004) revealed chlorophyll abundances in northwestern regions are larger than in other regions of the respective basins. The NW regions of the Arabian Sea and the Bay of Bengal have exhibited contrasting chlorophyll distribution patterns during El...

  11. Indicators of Coastal Water Quality: Annual Chlorophyll-a Concentration 1998-2007

    Data.gov (United States)

    National Aeronautics and Space Administration — The Annual Chlorophyll-a Concentrations component of the Indicators of Coastal Water Quality Collection consists of gridded satellite measurements of chlorophyll-a...

  12. Global NOAA CoastWatch Chlorophyll Frontal Product from MODIS/Aqua (NCEI Accession 0110333)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS/Aqua chlorophyll frontal products: the NOAA Okeanos operational production system produces near real-time chlorophyll frontal products (magnitude and...

  13. Portable chlorophyll meter (PCM-502) values are related to total chlorophyll concentration and photosynthetic capacity in papaya (Carica papaya L.)

    Science.gov (United States)

    This study was carried out to verify the practical use of the portable chlorophyll meter-PCM502 (PCM) in two papaya cultivars with contrasting green coloring of the leaf blade (‘Golden’: yellowish-green; ‘Solo’: dark green). The relationship was studied between the photosynthetic process and leaf n...

  14. Fluorescence detection: SPIE volume 743

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, E.R.

    1987-01-01

    This book contains proceedings arranged into four sessions. They are: Fluorescence spectroscopic techniques; Fluorescence in analysis and materials characterization; Fluorescence in medicine and biochemistry; and Fluorescence in criminalistics.

  15. Near real-time qualitative monitoring of lake water chlorophyll globally using GoogleEarth Engine

    Science.gov (United States)

    Zlinszky, András; Supan, Peter; Koma, Zsófia

    2017-04-01

    Monitoring ocean chlorophyll and suspended sediment has been made possible using optical satellite imaging, and has contributed immensely to our understanding of the Earth and its climate. However, lake water quality monitoring has limitations due to the optical complexity of shallow, sediment- and organic matter-laden waters. Meanwhile, timely and detailed information on basic lake water quality parameters would be essential for sustainable management of inland waters. Satellite-based remote sensing can deliver area-covering, high resolution maps of basic lake water quality parameters, but scientific application of these datasets for lake monitoring has been hindered by limitations to calibration and accuracy evaluation, and therefore access to such data has been the privilege of scientific users. Nevertheless, since for many inland waters satellite imaging is the only source of monitoring data, we believe it is urgent to make map products of chlorophyll and suspended sediment concentrations available to a wide range of users. Even if absolute accuracy can not be validated, patterns, processes and qualitative information delivered by such datasets in near-real time can act as an early warning system, raise awareness to water quality processes and serve education, in addition to complementing local monitoring activities. By making these datasets openly available on the internet through an easy to use framework, dialogue between stakeholders, management and governance authorities can be facilitated. We use GoogleEarthEngine to access and process archive and current satellite data. GoogleEarth Engine is a development and visualization framework that provides access to satellite datasets and processing capacity for analysis at the Petabyte scale. Based on earlier investigations, we chose the fluorescence line height index to represent water chlorophyll concentration. This index relies on the chlorophyll fluorescence peak at 680 nm, and has been tested for open ocean

  16. The small CAB-like proteins of the cyanobacterium Synechocystis sp. PCC 6803: their involvement in chlorophyll biogenesis for Photosystem II.

    Science.gov (United States)

    Hernandez-Prieto, Miguel A; Tibiletti, Tania; Abasova, Leyla; Kirilovsky, Diana; Vass, Imre; Funk, Christiane

    2011-09-01

    The five small CAB-like proteins (ScpA-E) of the cyanobacterium Synechocystis sp. PCC 6803 belong to the family of stress-induced light-harvesting-like proteins, but are constitutively expressed in a mutant deficient of Photosystem I (PSI). Using absorption, fluorescence and thermoluminescence measurements this PSI-less strain was compared with a mutant, in which all SCPs were additionally deleted. Depletion of SCPs led to structural rearrangements in Photosystem II (PSII): less photosystems were assembled; and in these, the Q(B) site was modified. Despite the lower amount of PSII, the SCP-deficient cells contained the same amount of phycobilisomes (PBS) as the control. Although the excess PBS were functionally disconnected, their fluorescence was quenched under high irradiance by the activated Orange Carotenoid Protein (OCP). Additionally the amount of OCP, but not of the iron-stress induced protein (isiA), was higher in this SCP-depleted mutant compared with the control. As previously described, the lack of SCPs affects the chlorophyll biosynthesis (Vavilin, D., Brune, D. C., Vermaas, W. (2005) Biochim Biophys Acta 1708, 91-101). We demonstrate that chlorophyll synthesis is required for efficient PSII repair and that it is partly impaired in the absence of SCPs. At the same time, the amount of chlorophyll also seems to influence the expression of ScpC and ScpD. 2011 Elsevier B.V. All rights reserved.

  17. Effect of automobile pollution on chlorophyll content of roadside urban trees

    Directory of Open Access Journals (Sweden)

    M. Iqbal

    2015-09-01

    Full Text Available The effect of automobile pollution was determined on chlorophyll content of four different tree species viz. Azadirachta indica L., Conocarpus erectus L., Guiacum officinale L.and Eucalyptus sp. growing along the roads of the city.  Significant changes in the level of chlorophyll “a”, chlorophyll “b” and total chlorophyll “a+b” were found in the leaves of four tree species (A. indica, C. erectus, G.officinale and Eucalyptus sp. collected from polluted sites (Airport, Malir Halt, Quaidabad as compared to control site (Karachi University Campus. Lowest concentration of chlorophyll “a”, chlorophyll “b” and chlorophyll “a+b” was recorded in the leaf samples of all tree species collected from Quaidabad site when compared with the leaf samples collected from control site. The highest levels of chlorophyll pigment were recorded in all tree species leave samples collected from Karachi University Campus.  Similarly, better levels of chlorophyll “a”, chlorophyll “b” and total chlorophyll “a+b” was observed in all tree species growing at Airport site as compared to plants growing at Malir Halt and Quaidabad sites.  This study clearly indicated that the vehicular activities induced air pollution problem and affected on the level of chlorophyll pigments in trees which were exposed to road side pollution.

  18. Decreasing the chlorophyll a/b ratio in reconstituted LHCII: Structural and functional consequences

    NARCIS (Netherlands)

    Kleima, F.J.; Hobe, S.; Calkoen, F.; Urbanus, M.L.; Peterman, E.J.G.; van Grondelle, R.; Paulsen, H.; van Amerongen, H.

    1999-01-01

    Trimeric (bT) and monomeric (bM) light-harvesting complex II (LHCII) with a chlorophyll a/b ratio of 0.03 were reconstituted from the apoprotein overexpressed in Escherichia coli. Chlorophyll/xanthophyll and chlorophyll/protein ratios of bT complexes and 'native' LHCII are rather similar, namely,

  19. Modeling the relationship between extractable chlorophyll and SPAD-502 readings for endangered plant species research

    Science.gov (United States)

    Tracy S. Hawkins; Emile S. Gardiner; Greg S. Comer

    2009-01-01

    Handheld chlorophyll meters have proven to be useful tools for rapid, nondestructive assessment of chlorophyll and nutrient status in various agricultural and arborescent plant species. We proposed that a SPAD-502 chlorophyll meter would provide valuable information when monitoring life cycle changes and intraspecific variation in...

  20. Survival Analysis

    CERN Document Server

    Miller, Rupert G

    2011-01-01

    A concise summary of the statistical methods used in the analysis of survival data with censoring. Emphasizes recently developed nonparametric techniques. Outlines methods in detail and illustrates them with actual data. Discusses the theory behind each method. Includes numerous worked problems and numerical exercises.