WorldWideScience

Sample records for chlorophyll fluorescence signals

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

    Science.gov (United States)

    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.

  2. 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)

  3. Remote sensing of chlorophyll a fluorescence of vegetation canopies. 2. Physiological significance of fluorescence signal in response to environmental stresses

    International Nuclear Information System (INIS)

    Measurements of laser-induced chlorophyll fluorescence of living leaves were compared to ecophysiological parameters, both in near and far field conditions. Near field measurements were carried out with a two-wavelength portable fluorometer, both in the laboratory and in the field. Results show significant changes of the 690 nm and 730 nm chlorophyll fluorescence bands in different environmental conditions. Water stress and carboxylation limitations also affect the fluorescence spectra. Far field measurements from a ground-operated fluorescence LIDAR system confirm those results. The F690 / F730 fluorescence ratio is then demonstrated as a good index for vegetation remote sensing. (author)

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

    Science.gov (United States)

    In this study, Chlorophyll Fluorescence (ChlF) was used to detect the onset of soybean plant injury from glyphosate, the most widely used herbicide. Thirty-six pots of non-glyphosate-resistant soybean (cultivar FM955LL) were randomly divided into three groups and treated with different doses of glyp...

  5. Temporal chlorophyll fluorescence signals to track changes in optical properties of maturing rice panicles exposed to high night temperature

    Czech Academy of Sciences Publication Activity Database

    Šebela, David; Quiňones, C.; Olejníčková, Julie; Jagadish, K. S. V.

    2015-01-01

    Roč. 177, jun (2015), s. 75-85. ISSN 0378-4290 R&D Projects: GA MŠk(CZ) LO1415; GA MŠk EE2.3.20.0246 Institutional support: RVO:67179843 Keywords : chlorophyll fluorescence (Chl-F) * grain filling * high night temperature (HNT) * maturing panicle * reflectance * Rice (Oryza sativa) Subject RIV: EH - Ecology, Behaviour Impact factor: 2.976, year: 2014

  6. Efficient Chlorophyll Fluorescence Measurements of Sugarcane

    Science.gov (United States)

    As with many crops, chlorophyll fluorescence emission is a promising tool for measuring responses of sugarcane (Saccharum spp.) to biotic and abiotic stresses. Chlorophyll fluorescence can be easily measured using portable fluorometers. However, several factors should be considered in order to op...

  7. Chlorophyll fluorescence emission spectrum inside a leaf

    OpenAIRE

    Pedrós Esteban, Roberto; Moya, Ismael; Goulas, Yves; Jacquemoud, Stéphane

    2008-01-01

    Chlorophyll a fluorescence can be used as an early stress indicator. Fluorescence is also connected to photosynthesis so it can be proposed for global monitoring of vegetation status from a satellite platform. Nevertheless, the correct interpretation of fluorescence requires accurate physical models. The spectral shape of the leaf fluorescence free of any re-absorption effect plays a key role in the models and is difficult to measure. We present a vegetation fluorescence emission spectrum fre...

  8. Remote sensing of chlorophyll fluorescence with GOSAT

    Science.gov (United States)

    Somkuti, Peter; Boesch, Hartmut; Parker, Robert

    2015-04-01

    Sun-induced chlorophyll fluorescence (Fs) emitted by plants as a by-product during photosynthesis carries information about their photosynthetic activity. It is possible to exploit space-based remote sensing measurements to retrieve the fluorescence signal and thus indirectly study carbon fluxes on a global scale. We implement a fluorescence retrieval based on the method pioneered by Frankenberg et al. (2011) into the framework of the University of Leicester Full-Physics GOSAT CO2 retrieval (UoL-FP). This physically-based approach is applied to high-resolution spectra at the edges of the O2 A-Band in the red to NIR range, that feature strong solar as well as a few weak O2 absorption lines. The fluorescence signal, which acts as an additional source, results in an in-filling of the measured solar absorption lines that are used to distinguish Fs from reflectance effects. By analysing GOSAT soundings from 2009 onwards, we examine global and regional long-term trends of Fs and compare them with parameters related to plant physiology, such as spectral vegetation indices and MODIS-derived model GPP values. Following Guanter et al. (2012) and Frankenberg et al. (2011), different regions and biomes are considered and we find that seasonal trends of both model GPP data as well as greenness indicators are well reproduced by our GOSAT-retrieved Fs.

  9. Bowel perforation detection using metabolic fluorescent chlorophylls

    Science.gov (United States)

    Han, Jung Hyun; Jo, Young Goun; Kim, Jung Chul; Choi, Sujeong; Kang, Hoonsoo; Kim, Yong-Chul; Hwang, In-Wook

    2016-03-01

    Thus far, there have been tries of detection of disease using fluorescent materials. We introduce the chlorophyll derivatives from food plants, which have longer-wavelength emissions (at >650 nm) than those of fluorescence of tissues and organs, for detection of bowel perforation. To figure out the possibility of fluorescence spectroscopy as a monitoring sensor of bowel perforation, fluorescence from organs of rodent models, intestinal and peritoneal fluids of rodent models and human were analyzed. In IVIS fluorescence image of rodent abdominal organ, visualization of perforated area only was possible when threshold of image is extremely finely controlled. Generally, both perforated area of bowel and normal bowel which filled with large amount of chlorophyll derivatives were visualized with fluorescence. The fluorescence from chlorophyll derivatives penetrated through the normal bowel wall makes difficult to distinguish perforation area from normal bowel with direct visualization of fluorescence. However, intestinal fluids containing chlorophyll derivatives from food contents can leak from perforation sites in situation of bowel perforation. It may show brighter and longer-wavelength regime emissions of chlorophyll derivatives than those of pure peritoneal fluid or bioorgans. Peritoneal fluid mixed with intestinal fluids show much brighter emissions in longer wavelength (at>650 nm) than those of pure peritoneal fluid. In addition, irrigation fluid, which is used for the cleansing of organ and peritoneal cavity, made of mixed intestinal and peritoneal fluid diluted with physiologic saline also can be monitored bowel perforation during surgery.

  10. Chlorophyll fluorescence of the testa of Brassica oleracea seeds as an indicator of seed maturity and seed quality

    OpenAIRE

    Jalink H.; Frandas A.; Schoor R. van der; Bino J.B.

    1998-01-01

    Chlorophyll fluorescence of the testa of seeds is proposed as a non-invasive method for the determination of maturity and quality of seeds. In this study cabbage seeds (Brassica oleracea) were sorted individually based on the chlorophyll fluorescence signals into four subsamples labeled with respect to their chlorophyll fluorescence signal (low, medium, high and very high). The results show that the magnitude of the chlorophyll fluorescence signal was inversely related to the quality of the s...

  11. Measurement of Sun Induced Chlorophyll Fluorescence Using Hyperspectral Satellite Imagery

    Science.gov (United States)

    Irteza, S. M.; Nichol, J. E.

    2016-06-01

    Solar Induced Chlorophyll Fluorescence (SIF), can be used as an indicator of stress in vegetation. Several scientific approaches have been made and there is considerable evidence that steady state Chlorophyll fluorescence is an accurate indicator of plant stress hence a reliable tool to monitor vegetation health status. Retrieval of Chlorophyll fluorescence provides an insight into photochemical and carbon sequestration processes within vegetation. Detection of Chlorophyll fluorescence has been well understood in the laboratory and field measurement. Fluorescence retrieval methods were applied in and around the atmospheric absorption bands 02B (Red wavelength) approximately 690 nm and 02A (Far red wavelengths) 740 nm. Hyperion satellite images were acquired for the years 2012 to 2015 in different seasons. Atmospheric corrections were applied using the 6S Model. The Fraunhofer Line Discrimanator (FLD) method was applied for retrieval of SIF from the Hyperion images by measuring the signal around the absorption bands in both vegetated and non vegetated land cover types. Absorption values were extracted in all the selected bands and the fluorescence signal was detected. The relationships between NDVI and Fluorescence derived from the satellite images are investigated to understand vegetation response within the absorption bands.

  12. Phytoplankton productivity quantified from chlorophyll fluorescence

    DEFF Research Database (Denmark)

    Hancke, Kasper; Dalsgaard, Tage; Sejr, Mikael Kristian;

    Phytoplankton are the main food source for marine life, and accurate uantification of its productivity is essential for understanding how marine food webs function. As a novel non-invasive technology, chlorophyll fluorescence can be used to assess in situ primary production in phytoplankton...

  13. 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.

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

    OpenAIRE

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

    2011-01-01

    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 establ...

  15. Red and far red sun-induced chlorophyll fluorescence as a measure of plant photosynthesis

    OpenAIRE

    M. Rossini; L. Nedbal; Luis Guanter; A. Ač; L. Alonso; A. Burkart; S. Cogliati; R. Colombo; A. Damm; M. Drusch; J. Hanus; R. Janoutova; T. Julitta; P. Kokkalis; J. Moreno

    2015-01-01

    Remote estimation of Sun-induced chlorophyll fluorescence emitted by terrestrial vegetation can provide an unparalleled opportunity to track spatiotemporal variations of photosynthetic efficiency. Here we provide the first direct experimental evidence that the two peaks of the chlorophyll fluorescence spectrum can be accurately mapped from high-resolution radiance spectra and that the signal is linked to variations in actual photosynthetic efficiency. Red and far red fluorescence measured usi...

  16. Remote sensing of terrestrial chlorophyll fluorescence from space

    OpenAIRE

    Frankenberg, Christian; Berry, Joseph; Guanter, Luis; JOINER Joanna

    2013-01-01

    High-resolution spectrometers enable new avenues in global carbon cycle research, including the first accurate retrievals of chlorophyll fluorescence from space as an indicator of photosynthetic activity.

  17. Chlorophyll a + b content and chlorophyll fluorescence in avocado

    Science.gov (United States)

    One Tonnage (T) and one Simmonds (S) avocado tree and four TxS crosses were evaluated for differences in chlorophyll content and maximal quantum yield of photosystem II in sun and shade-type leaves. Total chlorophyll content by area (Chl a+bar) ranged from 981 mg m-2 in TxS240 to 4339 mg m-2 in Simm...

  18. Modulated Chlorophyll "a" Fluorescence: A Tool for Teaching Photosynthesis

    Science.gov (United States)

    Marques da Silva, Jorge; Bernardes da Silva, Anabela; Padua, Mario

    2007-01-01

    "In vivo" chlorophyll "a" fluorescence is a key technique in photosynthesis research. The recent release of a low cost, commercial, modulated fluorometer enables this powerful technology to be used in education. Modulated chlorophyll a fluorescence measurement "in vivo" is here proposed as a tool to demonstrate basic photosynthesis phenomena to…

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

    NARCIS (Netherlands)

    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 da

  20. Herbivory of wild Manduca sexta causes fast down-regulation of photosynthetic efficiency in Datura wrightii: an early signaling cascade visualized by chlorophyll fluorescence.

    Science.gov (United States)

    Barron-Gafford, Greg A; Rascher, Uwe; Bronstein, Judith L; Davidowitz, Goggy; Chaszar, Brian; Huxman, Travis E

    2012-09-01

    Plants experiencing herbivory suffer indirect costs beyond direct loss of leaf area, but differentially so based on the herbivore involved. We used a combination of chlorophyll fluorescence imaging and gas exchange techniques to quantify photosynthetic performance, the efficiency of photochemistry, and heat dissipation to examine immediate and longer-term physiological responses in the desert perennial Datura wrightii to herbivory by tobacco hornworm, Manduca sexta. Herbivory by colony-reared larvae yielded no significant reduction in carbon assimilation, whereas herbivory by wild larvae induced a fast and spreading down-regulation of photosynthetic efficiency, resulting in significant losses in carbon assimilation in eaten and uneaten leaves. We found both an 89 % reduction in net photosynthetic rates in herbivore-damaged leaves and a whole-plant response (79 % decrease in undamaged leaves from adjacent branches). Consequently, herbivory costs are higher than previously estimated in this well-studied plant-insect interaction. We used chlorophyll fluorescence imaging to elucidate the mechanisms of this down-regulation. Quantum yield decreased up to 70 % in a small concentric band surrounding the feeding area within minutes of the onset of herbivory. Non-photochemical energy dissipation by the plant to avoid permanent damage was elevated near the wound, and increased systematically in distant areas of the leaf away from the wound over subsequent hours. Together, the results underscore not only potential differences between colony-reared and wild-caught herbivores in experimental studies of herbivory but also the benefits of quantifying physiological responses of plants in unattacked leaves. PMID:22576017

  1. 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.

  2. Instrumentation in Developing Chlorophyll Fluorescence Biosensing: A Review

    OpenAIRE

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

    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...

  3. Mahalanobis distance screening of Arabidopsis mutants with chlorophyll fluorescence

    Czech Academy of Sciences Publication Activity Database

    Codrea, C. C.; Hakala-Yatkin, M.; Karlund-Marttila, A.; Nedbal, Ladislav; Aittokallio, T.; Nevalainen, O. S.; Tyystjärvi, E.

    2010-01-01

    Roč. 105, č. 3 (2010), s. 273-283. ISSN 0166-8595 Institutional research plan: CEZ:AV0Z60870520 Keywords : arabidopsis thaliana * chlorophyll fluorescence * fluorescence imaging * mutant detection * outlier detection Subject RIV: EH - Ecology, Behaviour Impact factor: 2.410, year: 2010 http://www.springerlink.com/content/x3586512462pn006/

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

    OpenAIRE

    Ryszard Kosson

    2013-01-01

    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 ...

  5. Instrumentation in Developing Chlorophyll Fluorescence Biosensing: A Review

    Directory of Open Access Journals (Sweden)

    Jesus R. Millan-Almaraz

    2012-08-01

    Full Text Available 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.

  6. Chlorophyll a fluorescence to phenotype wheat genotypes for heat tolerance

    DEFF Research Database (Denmark)

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

    . Chlorophyll a fluorescence has been a versatile tool in photosynthesis research to measure plant responses to various abiotic stresses that affect PSII. We aim to establish a reproducible protocol to measure response of wheat genotypes to high temperature, based on the physiological marker, maximum quantum......%. Our protocol seems to be stable over environments since interaction between genotypes and the three repeated experiments separated in time was not statistically significant. The chlorophyll a fluorescence protocol may enable identification of wheat lines reliably more or less tolerant to heat stress...

  7. Photoinhibition of Photosystems I and II Using Chlorophyll Fluorescence Measurements

    Science.gov (United States)

    Quiles, Maria Jose

    2005-01-01

    In this study the photoinhibition of photosystems (PS) I and II caused by exposure to high intensity light in oat ("Avena sativa," var Prevision) is measured by the emission of chlorophyll fluorescence in intact leaves adapted to darkness. The maximal quantum yield of PS II was lower in plants grown under high light intensity than in plants grown…

  8. Chlorophyll Fluorescence Analysis of Cyanobacterial Photosynthesis and Acclimation

    OpenAIRE

    Campbell, Douglas; Hurry, Vaughan; Adrian K Clarke; 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 fluore...

  9. Photochemical and photoelectrochemical quenching of chlorophyll fluorescence in photosystem II

    Czech Academy of Sciences Publication Activity Database

    Vredenberg, W.; Durchan, M.; Prášil, Ondřej

    2009-01-01

    Roč. 1787, č. 12 (2009), s. 1468-1478. ISSN 0005-2728 R&D Projects: GA ČR GA206/08/1683 Institutional research plan: CEZ:AV0Z50200510 Keywords : Chlorophyll a fluorescence * Photosystem II * Heterogeneity Subject RIV: EE - Microbiology, Virology Impact factor: 3.688, year: 2009

  10. Chlorophyll a fluorescence to phenotype wheat genotypes for heat tolerance

    DEFF Research Database (Denmark)

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

    In prospects of global climate change, heat stress is a rising constraint for the productivity of wheat (Triticum aestivum L.). It is a heat-susceptible crop beyond 17-23oC temperature throughout its phenological stages, flowering phase being the most sensitive stage. Chlorophyll a fluorescence...

  11. A new relative referencing method for crop monitoring using chlorophyll fluorescence

    Science.gov (United States)

    Norikane, J.; Goto, E.; Kurata, K.; Takakura, T.

    2003-01-01

    The measurement of plant chlorophyll fluorescence has been used for many years as a method to monitor a plant's health status. These types of methods have been mostly relegated to the laboratory. The newly developed Relative Referencing Method allows for the measurement of chlorophyll fluorescence under artificial lighting conditions. The fluorescence signal can be determined by first taking a reference signal measurement, then a second measurement with an additional fluorescence excitation source. The first signal can then be subtracted from the second and the plant's chlorophyll fluorescence due to the second lighting source can be determined. With this simple approach, a photosynthesizing plant can be monitored to detect signs of water stress. Using this approach experiments on tomato plants have shown that it was possible to detect water stress, while the plants were continuously illuminated by fluorescent lamps. This method is a promising tool for the remote monitoring of crops grown in a CELSS-type application. Published by Elsevier Science Ltd on behalf of COSPAR.

  12. Modelling GPP and chlorophyll fluorescence using SCOPE (Invited)

    Science.gov (United States)

    van der Tol, C.; Verhoef, W.

    2009-12-01

    Chlorophyll fluorescence of Photosystem II (PSII) is a measure for photosynthetic processes and the functional state of the vegetation. Research in the past has focused on the active (light-induced) measurement of fluorescence at leaf and field scale. Current research focuses on the potential of satellite remote sensing of passive (solar-induced) chlorophyll fluorescence of PSII to monitor photosynthetic processes of terrestrial vegetation at large spatial scales. This research includes the relationship between top-of-canopy (TOC) fluorescence and gross primary production (GPP). The recently developed model SCOPE simulates this relationship using three sub-models. The first sub-model (FLUSPECT) is based on PROSPECT and describes leaf fluorescence spectra as a function of their chemical composition. The second sub-model describes the effects of leaf temperature, humidity and irradiance on these spectra and on actual photosynthesis. The third sub-model is a canopy level radiative transfer model, which calculates the scattering and absorption of solar radiation and fluorescence within a canopy, and computes the TOC spectrum of fluorescence in observation direction. A sensitivity analysis of the model shows a strong relationship between solar induced fluorescence and GPP at canopy level. This relationship is consistent with data from field campaigns. Fluorescence and GPP are sensitive to stress conditions including high leaf temperatures and water stress.

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

    OpenAIRE

    Junsheng Wang; Jinyang Sun; Yongxin Song; Yongyi Xu; Xinxiang Pan; Yeqing Sun; Dongqing Li

    2013-01-01

    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 anal...

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

    OpenAIRE

    Damm, A.; Schickling, A.; Schlapfer, D.; M. E. Schaepman; 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 not fully understood yet. Several factors influence the Fs signal and need to be quantified. However, the absence of dedicated imaging spectrometers limits the experimental data for such investigat...

  15. Chlorophyll fluorescence imaging of cadmium-treated white cabbage plants

    Directory of Open Access Journals (Sweden)

    Borek M.

    2013-04-01

    Full Text Available The chlorophyll fluorescence imaging technique is a valuable tool to study the impact of heavy metal stress in plants. The aim of this paper was to investigate the influence of Cd on photosynthetic apparatus of white cabbage (Brassica oleracea subsp. capitata f. alba plants. Two cabbage cultivars ‘Ditmarska Najwcześniejsza’ (‘DN’; early and ‘Amager Polana’ (‘AP’; late were used. Cd was applied before planting seedlings (10 mg Cd kg−1 DM of soil.. Measurements were performed at the 3rd leaf after 2 weeks of planting. The level of Cd-induced stress to plants was estimated by chlorophyll (Chl content (photometrically and analyses of images and numeric values of the major fluorescence parameters of Chl (Chl fluorescence imaging system FluorCam. Cd negatively affected the chlorophyll content and Fv/Fm, Fv’/Fm’, Φ PSII and qP in leaves of early cultivar of white cabbage. However, in the case of late cv. we did not observe such distinct changes. It suggests that late cultivars. are more resistant to Cd than the early ones. Considering methodological aspect of the study, Chl fluorescence imaging can better reveal some alterations within the leaf, because numeric values of specific parameters, which are the averaged data collected from the whole leaf, cannot reflect the tissue specificity. Abbreviations: HM – heavy metal, Cd – cadmium, Chl – chlorophyll, Fv/Fm – photochemical efficiency of PSII in the dark-adapted state, F‘v’/F‘m’ – PSII maximum efficiency, Φ PSII – quantum efficiency of PSII electron transport, NPQ – nonphotochemical quenching of maximal Chl fluorescence, qP – photochemical quenching coefficient.

  16. 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.

  17. Quenching of chlorophyll fluorescence induced by silver nanoparticles.

    Science.gov (United States)

    Queiroz, A M; Mezacasa, A V; Graciano, D E; Falco, W F; M'Peko, J-C; Guimarães, F E G; Lawson, T; Colbeck, I; Oliveira, S L; Caires, A R L

    2016-11-01

    The interaction between chlorophyll (Chl) and silver nanoparticles (AgNPs) was evaluated by analyzing the optical behavior of Chl molecules surrounded by different concentrations of AgNPs (10, 60, and 100nm of diameter). UV-Vis absorption, steady state and time-resolved fluorescence measurements were performed for Chl in the presence and absence of these nanoparticles. AgNPs strongly suppressed the Chl fluorescence intensity at 678nm. The Stern-Volmer constant (KSV) showed that fluorescence suppression is driven by the dynamic quenching process. In particular, KSV was nanoparticle size-dependent with an exponential decrease as a function of the nanoparticle diameter. Finally, changes in the Chl fluorescence lifetime in the presence of nanoparticles demonstrated that the fluorescence quenching may be induced by the excited electron transfer from the Chl molecules to the metal nanoparticles. PMID:27280858

  18. Chlorophyll fluorescence control in microalgae by biogenic guanine crystals

    Science.gov (United States)

    Miyashita, Yuito; Iwasaka, Masakazu; Endo, Hirotoshi

    2015-05-01

    Magnetic fields were applied to water suspensions of guanine crystals to induce changes in light scattering as a possible way to control photosynthesis in microalgae. The effect of guanine microcrystals with and without an applied magnetic field on the photosynthesis of a unicellular microalgae (plant), Pleurochrysis. carterae (P. carterae), was investigated by examining chlorophyll fluorescence. The fluorescence intensity at 600-700 nm of the photosynthetic cells increased remarkably when the concentration ratio of guanine microcrystals was 10 times larger than that of the cells. This increase in fluorescence occurred reproducibly and was proportional to the amount of guanine microcrystals added. It is speculated that the guanine microcrystals enhance the intensity of the excitation light on the cells by concentrating the excitation light or prolonging the time of light exposure to the cells. Moreover, applying a 500-mT magnetic field allowed modulation of the fluorescence intensity, depending on the direction of the fluorescence light.

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

    OpenAIRE

    Miros³awa Ostrowska; Dimitrii N. Matorin; Dariusz Ficek

    2000-01-01

    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...

  20. Chlorophyll fluorescence analysis and imaging in plant stress and disease

    Energy Technology Data Exchange (ETDEWEB)

    Daley, P.F.

    1994-12-01

    Quantitative analysis of chlorophyll fluorescence transients and quenching has evolved rapidly in the last decade. Instrumentation capable of fluorescence detection in bright actinic light has been used in conjunction with gas exchange analysis to build an empirical foundation relating quenching parameters to photosynthetic electron transport, the state of the photoapparatus, and carbon fixation. We have developed several instruments that collect video images of chlorophyll fluorescence. Digitized versions of these images can be manipulated as numerical data arrays, supporting generation of quenching maps that represent the spatial distribution of photosynthetic activity in leaves. We have applied this technology to analysis of fluorescence quenching during application of stress hormones, herbicides, physical stresses including drought and sudden changes in humidity of the atmosphere surrounding leaves, and during stomatal oscillations in high CO{sub 2}. We describe a recently completed portable fluorescence imaging system utilizing LED illumination and a consumer-grade camcorder, that will be used in long-term, non-destructive field studies of plant virus infections.

  1. Laser and sunlight-induced fluorescence from chlorophyll pigments

    Science.gov (United States)

    Kim, H. H.; Brown, K. S.

    1986-01-01

    Fluorescence properties of chlorophyll pigment bearing plant foliage utilizing a 337 nm nitrogen laser and integrating sphere were studied. Measured yields, in terms of number of photons emitted per 100 photons absorbed, range from 1.5 to 0.1 for the 685 nm peak, and from 4.2 to 0.2 for the 730 nm peak. Decreasing order of magnitude puts herbaceous leaves ahead of all others followed by broad leaves of hardwoods and coniferous needles. Meaningful quantization for the fluorescence peaks at 430 and 530 nm could not be attained. Passive monitoring of these fluorescence peaks is successful only for the 685 nm from the ocean surface. Field data show the reflectance changes at 685 nm due to the algae presence amounts to 1% at most.

  2. 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

  3. Contribution of chlorophyll fluorescence to the apparent vegetation reflectance

    International Nuclear Information System (INIS)

    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

  4. Phenoplant: a web resource for the exploration of large chlorophyll fluorescence image datasets

    OpenAIRE

    Rousseau, Céline; Hunault, Gilles; Gaillard, Sylvain; Bourbeillon, Julie; Montiel, Gregory; Simier, Philippe; Campion, Claire; Jacques, Marie Agnes; Belin, Etienne; Boureau, Tristan

    2015-01-01

    Background Image analysis is increasingly used in plant phenotyping. Among the various imaging techniques that can be used in plant phenotyping, chlorophyll fluorescence imaging allows imaging of the impact of biotic or abiotic stresses on leaves. Numerous chlorophyll fluorescence parameters may be measured or calculated, but only a few can produce a contrast in a given condition. Therefore, automated procedures that help screening chlorophyll fluorescence image datasets are needed, especiall...

  5. Bark and leaf chlorophyll fluorescence are linked to wood structural changes in Eucalyptus saligna

    OpenAIRE

    Johnstone, Denise; Tausz, Michael; Moore, Gregory; Nicolas, Marc

    2014-01-01

    Wood structure and wood anatomy are usually considered to be largely independent of the physiological processes that govern tree growth. This paper reports a statistical relationship between leaf and bark chlorophyll fluorescence and wood density. A relationship between leaf and bark chlorophyll fluorescence and the quantity of wood decay in a tree is also described. There was a statistically significant relationship between the leaf chlorophyll fluorescence parameter F v/F m and wood density...

  6. Fluorescent indices of oak and wheat leaves in dependence on chlorophyll content

    Science.gov (United States)

    Kalmatskaya, Olesya Ð. ń.; Karavaev, Vladimir A.; Gunar, Lyudmila E.

    2016-04-01

    Fluorescence spectra and fluorescence induction curves of the leaves of two plant species in dependence on chlorophyll content were studied. Red oak (Quercus rubra L.) leaves upon the autumn chlorophyll degradation, as well as wheat leaves (Triticum aestivum L.) at various stages of ontogenesis showed linear dependence between the ratio ω = F740 / F685 (the ratio of the maximum values of fluorescence at respective wavelengths) and chlorophyll content. In both cases, parameter Fv / Fm (the relative value of the variable fluorescence) remained almost unchanged up to significant reduction of chlorophyll content, indicating on maintaining the high photochemical activity of photosystem 2.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Models of fluorescence and photosynthesis for interpreting measurements of solar-induced chlorophyll fluorescence

    OpenAIRE

    van der Tol, C.; Berry, J. A.; P. K. E. Campbell; Rascher, U.

    2014-01-01

    We have extended a conventional photosynthesis model to simulate field and laboratory measurements of chlorophyll fluorescence at the leaf scale. The fluorescence paramaterization is based on a close nonlinear relationship between the relative light saturation of photosynthesis and nonradiative energy dissipation in plants of different species. This relationship diverged only among examined data sets under stressed (strongly light saturated) conditions, possibly caused by differences in xanth...

  9. Changes of Photosystem Ⅱ Electron Transport in the Chlorophyll-deficient Oilseed Rape Mutant Studied by Chlorophyll Fluorescence and Thermoluminescence

    Institute of Scientific and Technical Information of China (English)

    Jun-Wei Guo; Jin-Kui Guo; Yun Zhao; Lin-Fang Du

    2007-01-01

    The photosystem Ⅱ (PSII) complex of photosynthetic membranes comprises a number of chlorophyll-binding proteins that are important to the electron flow. Here we report that the chlorophyll b-deficient mutant has de creased the amount of light-harvesting complexes with an increased amount of some core polypeptides of PSII,including CP43 and CP47. By means of chlorophyll fluorescence and thermoluminescence, we found that the ratio of Fv/Fm, qP and electron transport rate in the chlorophyll b-deficient mutant was higher compared to the wild type.In the chlorophyll b-deficient mutant, the decay of the primary electron acceptor quinones (QA-) reoxidation was decreased, measured by the fluorescence. Furthermore, the thermolumlnescence studies in the chlorophyll b deficient mutant showed that the B band (S2/S3QB-) decreased slightly and shifted up towards higher temperatures.In the presence of dichlorophenyl-dimethylurea, which is inhibited in the electron flow to the second electron acceptor quinines (QB) at the PSII acceptor side, the maximum of the Q band (S2QA-) was decreased slightly and shifted down to lower temperatures, compared to the wild type. Thus, the electron flow within PSll of the chlorophyll b-deficient mutant was down-regulated and characterized by faster oxidation of the primary electron acceptor quinine QA- via forward electron flow and slower reduction of the oxidation S states.

  10. Contribution of Chlorophyll Fluorescence to the Reflectance of Corn Foliage

    Science.gov (United States)

    Campbell, Petya K. Entcheva; Middleton, Elizabeth M.; Corp, L. A.; McMurtrey, J. E.; Kim, M. S.; Chappelle, E. W.; Butcher, L. M.; Ranson, K. Jon (Technical Monitor)

    2002-01-01

    To assess the contribution of chlorophyll fluorescence (ChlF) to apparent reflectance (Ra) in the red/far-red, spectra were collected on a C4 agricultural species (corn, Zea Mays L.) under conditions ranging from nitrogen deficiency to excess. A significant contribution of ChlF to Ra was observed, with on average 10-25% at 685nm and 2-6% at 740nm of Ra being due to ChlF. Higher ChlF was consistently measured from the abaxial leaf surface as compared to the adaxial. Using 350-665nm excitation, the study confirms the trends in three ChlF ratios established previously by active F technology, suggesting that the ChlF utility this technology has developed for monitoring vegetation physiological status is likely applicable also under natural solar illumination.

  11. Canopy Level Chlorophyll Fluorescence and the PRI in a Cornfield

    Science.gov (United States)

    Middleton, Elizabeth M.; Cheng, Yen-Ben; Corp, Lawrence A.; Campbell, Petya K. E.; Huemmrich, K. Fred; Zhang, Qingyuan; Kustas, William P.

    2012-01-01

    Two bio-indicators, the Photochemical Reflectance Index (PRI) and solar-induced red and far-red Chlorophyll Fluorescence (SIF), were derived from directional hyperspectral observations and studied in a cornfield on two contrasting days in the growing season. Both red and far-red SIF exhibited higher values on the day when the canopy in the early senescent stage, but only the far-red SIF showed sensitivity to viewing geometry. Consequently, the red/far-red SIF ratio varied greatly among azimuth positions while the largest values were obtained for the "hotspot" at both growth stages. This ratio was lower (approx.0.88 +/- 0.4) in early July than in August when the ratio approached equivalence (near approx.1). In concert, the PRI exhibited stronger responses to both zenith and azimuth angles and different values on the two growth stages. The potential of using these indices to monitor photosynthetic activities needs further investigation

  12. Contribution of Chlorophyll Fluorescence to the Apparent Reflectance of Vegetation

    Science.gov (United States)

    Campbell, P. K. Entcheva; Middleton, E. M.; Kim, M. S.

    2007-01-01

    Current strategies for monitoring the physiologic status of terrestrial vegetation rely on remote sensing reflectance (R) measurements, whi ch provide estimates of relative vegetation vigor based primarily on chlorophyll content. Vegetation chlorophyll fluorescence (CF) offers a non-destructive alternative and a more direct approach for diagnosis of vegetation stress before a significant reduction in chlorophyll content has occurred. Thus, monitoring of vegetation vigor based on CF may allow earlier stress detection and more accurate carbon sequestra tion estimates, than is possible using R data alone. However, the observed apparent vegetation reflectance (Ra) in reality includes contrib utions from both the reflected and fluoresced radiation. The aim of t his study is to determine the relative R and CF fractions contributing to Ra from the vegetation in the red to near-infrared region of the spectrum. The practical objectives of the study are to: 1) evaluate t he relationship between CF and R at the foliar level for corn, soybean, maple; and 2) for corn, determine if the relationship established f or healthy (optimal N) vegetation changes under N defiiency. To obtai n generally applicable results, experimental measurements were conducted on unrelated crop and tree species (maple, soybean and corn), unde r controlled conditions and a gradient of inorganic N fertilization l evels. Optical R spectra and actively induced CF emissions were obtained on the same foliar samples, in conjunction with measurements of p hotosynthetic function, pigment levels, and C and N content. The comm on spectral trends or similarities were examined. On average, 10-20% of apparent R at 685 nm was actually due to CF. The spectral trends in steady and maximum F varied significantly, with Fs (especially red) showing higher ability for species and treatment separation. The relative contribution of ChF to R varied significantly among species, with maple emitting much higher F amounts, as

  13. Chlorophyll bleaching by UV-irradiation in vitro and in situ: Absorption and fluorescence studies

    International Nuclear Information System (INIS)

    Chlorophyll bleaching by UV-irradiation has been studied by absorbance and fluorescence spectroscopy in extracts containing mixtures of photosynthetic pigments, in acetone and n-hexane solutions, and in aqueous thylakoid suspensions. Chlorophyll undergoes destruction (bleaching) accompanied by fluorescent transient formation obeying first-order kinetics. The bleaching is governed by UV-photon energy input, as well as by different chlorophyll molecular organizations in solvents of different polarities (in vitro), and in thylakoids (in situ). UV-C-induced bleaching of chlorophylls in thylakoids is probably caused by different mechanisms compared to UV-A- and UV-B-induced bleaching

  14. Ocean color spectral variability studies using solar-induced chlorophyll fluorescence

    Science.gov (United States)

    Hoge, Frank E.; Swift, Robert N.

    1987-01-01

    It is suggested that chlorophyll-induced ocean color spectral variability can be studied using only a passive airborne spectroradiometer instrument, with solar-induced chlorophyll fluorescence used as the standard against which all correlations are performed. The intraspectral correlation (ISC) method is demonstrated with results obtained during an airborne mapping mission in the New York Bight. The curvature algorithm is applied to the solar-induced chlorophyll fluorescence at about 690 nm, and good agreement is found with results obtained using active-passive correlation spectroscopy. The ISC method has application to spectral variability and resulting chlorophyll concentration measurement in different environmental conditions and in different water types.

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

    OpenAIRE

    Zhuoya Ni; Zhigang Liu; Hongyuan Huo; Zhao-Liang Li; Françoise Nerry; Qingshan Wang; Xiaowen Li

    2015-01-01

    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 leav...

  16. From the shape of the vertical profile of in vivo fluorescence to Chlorophyll-a concentration

    Science.gov (United States)

    Mignot, A.; Claustre, H.; D'Ortenzio, F.; Xing, X.; Poteau, A.; Ras, J.

    2011-08-01

    In vivo fluorescence of Chlorophyll-a (Chl-a) is a potentially useful property to study the vertical distribution of phytoplankton biomass. However the technique is presently not fully exploited as it should be, essentially because of the difficulties in converting the fluorescence signal into an accurate Chl-a concentration. These difficulties arise noticeably from natural variations in the Chl-a fluorescence relationship, which is under the control of community composition as well as of their nutrient and light status. As a consequence, although vertical profiles of fluorescence are likely the most recorded biological property in the open ocean, the corresponding large databases are underexploited. Here with the aim to convert a fluorescence profile into a Chl-a concentration profile, we test the hypothesis that the Chl-a concentration can be gathered from the sole knowledge of the shape of the fluorescence profile. We analyze a large dataset from 18 oceanographic cruises conducted in case-1 waters from the highly stratified hyperoligotrophic waters (surface Chl-a = 0.02 mg m-3) of the South Pacific Gyre to the eutrophic waters of the Benguela upwelling (surface Chl-a = 32 mg m-3) and including the very deep mixed waters in the North Atlantic (Mixed Layer Depth = 690 m). This dataset encompasses more than 700 vertical profiles of Chl-a fluorescence as well as accurate estimations of Chl-a by High Performance Liquid Chromatography (HPLC). Two typical fluorescence profiles are identified, the uniform profile, characterized by a homogeneous layer roughly corresponding to the mixed layer, and the non-uniform profile, characterized by the presence of a Deep Chlorophyll Maximum. Using appropriate mathematical parameterizations, a fluorescence profile is subsequently represented by 3 or 5 shape parameters for uniform or non-uniform profiles, respectively. For both situations, an empirical model is developed to predict the "true" Chl-a concentration from these shape

  17. Impact of petrochemicals on the photosynthesis of Halophila ovalis using chlorophyll fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Ralph, P.J.; Burchett, M.D. [University of Sydney (Australia). Institute for Coastal Resource Management and Dept. of of Environmental Biology and Horticulture

    1998-06-01

    Laboratory-cultured Halophila ovalis showed tolerance to petrochemical exposure up to 1% (w/v) solution of Bass Strait crude oil, an oil dispersant (Corexit 9527) and a mixture of crude oil and dispersant. Quantum yield, as measured by chlorophyll fluorescence, was the most sensitive measure of the photosynthetic processes affected by petrochemical. The results indicated clearly that chlorophyll fluorescence was effective at monitoring the onset and development of stress and recovery of H. ovalis when exposed to crude oil, dispersant and a mixture of the two compounds. Photosynthetic pigment content generally confirmed the chlorophyll fluorescence response; however, several anomalies occurred. (author)

  18. Impact of petrochemicals on the photosynthesis of Halophila ovalis using chlorophyll fluorescence

    International Nuclear Information System (INIS)

    Laboratory-cultured Halophila ovalis showed tolerance to petrochemical exposure up to 1% (w/v) solution of Bass Strait crude oil, an oil dispersant (Corexit 9527) and a mixture of crude oil and dispersant. Quantum yield, as measured by chlorophyll fluorescence, was the most sensitive measure of the photosynthetic processes affected by petrochemical. The results indicated clearly that chlorophyll fluorescence was effective at monitoring the onset and development of stress and recovery of H. ovalis when exposed to crude oil, dispersant and a mixture of the two compounds. Photosynthetic pigment content generally confirmed the chlorophyll fluorescence response; however, several anomalies occurred. (author)

  19. Chlorophyll fluorescence in vivo as a probe for rapid measurement of tolerance to ultraviolet radiation

    International Nuclear Information System (INIS)

    Chlorophyll fluorescence in vivo was progressively lost in pea leaves irradiated with either short or long-wave light. The changes were consistent with the development in the intact leaves of an inhibitory site on the photooxidizing side of photosystem II. In contrast, leaves of two species of Agave, plants regarded as more resistant to UV radiation, showed only minor changes in chlorophyll fluorescence. Agave americana was affected less than A. attenuata. The application of measurements of chlorophyll fluorescence in vivo to screening for tolerance to UV radiation is discussed. (author)

  20. Study of plant fluorescence prop erties based on laser-induced chlorophyll fluorescence lifetime imaging technology%基于激光诱导叶绿素荧光寿命成像技术的植物荧光特性研究∗

    Institute of Scientific and Technical Information of China (English)

    万文博; 华灯鑫; 乐静; 闫哲; 周春艳

    2015-01-01

    Plant fluorescence is a susceptible signal in plant fluorescence remote sensing detection. In order to solve this problem, a technique for plant chlorophyll fluorescence lifetime imaging is presented to evaluate living status for plant growth and environmental monitoring. A concave lens is used to expand laser beam at a wavelength of 355 nm, and the living plant is exposed in this laser light source to excite chlorophyll fluorescence. And the chlorophyll fluorescence signals are detected by an intensification charge coupled device. Time resolved measurement method is used in this article, so that every time the same fluorescence signals can be excited by the same laser pulse. Meanwhile, the delay time needed for triggering intensification charge coupled device should be changed consecutively, and the whole discrete fluorescence signal can be obtained. The discrete fluorescence signals from the particular location points of the plant are fitted. An improved method of forward iterative deconvolution is used to retrieve the corresponding fluorescence lifetime, and the high-precision fluorescence lifetime can be obtained. Furthermore, the fluorescence lifetime values at all the location points are retrieved to obtain the distribution map of chlorophyll fluorescence lifetime. This method can give the chlorophyll fluorescence image efficiently. The distribution map of fluorescence lifetime can more effectively reflect the plant chlorophyll concentration than the fluorescence intensity image does. The physical property of chlorophyll fluorescence lifetime from living plants has been studied preliminarily, indicating that the plant physiological status is related to its fluorescence lifetime to a certain extent; and the chlorophyll fluorescence lifetime and plant environment have a subtle and complex correlation. In the future, the relationship between chlorophyll fluorescence lifetime and plant environment will be expected to study with the cooperation of biophysicist.

  1. Seasonal, Diurnal and Vertical Variation of Chlorophyll Fluorescence on Phyllostachys humilis in Ireland

    OpenAIRE

    Van Goethem, Davina; De Smedt, Sebastiaan; Valcke, Roland; Potters, Geert; Samson, Roeland

    2013-01-01

    In recent years, temperate bamboo species have been introduced in Europe not only as an ornamental plant, but also as a new biomass crop. To measure adaptation stress of bamboo to the climate of Western Europe, chlorophyll fluorescence was measured on a diurnal and seasonal basis in Ballyboughal, Co. Dublin, Ireland. Measurements were attained on the leaves of each node of Phyllostachys humilis. The most frequently used parameter in chlorophyll fluorescence is the photosynthetic efficiency (F...

  2. Assessment of Salt Tolerance in Pepper Using Chlorophyll Fluorescence and Mineral Compositions

    OpenAIRE

    Mohammad Reza Zare Bavani; Gholamali Peyvast; Mahmoud Ghasemnezhad; Akbar Forghani

    2016-01-01

    In this study, leaf chlorophyll fluorescence and mineral compositions was used to compare pepper (Capsicum annuum L.) cultivars response to salt stress. Twentysix pepper cultivars were exposed to salt stress (100 mM NaCl) during two weeks. Thereafter, chlorophyll fluorescence components, stress tolerance index (STI), sodium, potassium and calcium content were measured. The results showed that a significant difference has been found among pepper cultivars for all studied characteristics....

  3. Development of a canopy Solar-induced chlorophyll fluorescence measurement instrument

    International Nuclear Information System (INIS)

    A portable solar-induced chlorophyll fluorescence detecting instrument based on Fraunhofer line principle was designed and tested. The instrument has a valid survey area of 1.3 × 1.3 meter when the height was fixed to 1.3 meter. The instrument uses sunlight as its light source. The instrument is quipped with two sets of special photoelectrical detectors with the centre wavelength at 760 nm and 771 nm respectively and bandwidth less than 1nm. Both sets of detectors are composed of an upper detector which are used for detecting incidence sunlight and a bottom detector which are used for detecting reflex light from the canopy of crop. This instrument includes photoelectric detector module, signal process module, A/D convert module, the data storage and upload module and human-machine interface module. The microprocessor calculates solar-induced fluorescence value based on the A/D values get from detectors. And the value can be displayed on the instrument's LCD, stored in the flash memory of instrument and can also be uploaded to PC through the PC's serial interface. The prototype was tested in the crop field and the results demonstrate that the instrument can measure the solar-induced chlorophyll value exactly with the correlation coefficients was 0.9 compared to the values got from Analytical Spectral Devices FieldSpec Pro spectrometer. This instrument can diagnose the plant growth status by the acquired spectral response

  4. Detection of Fluorescence from Single Chlorophyll a Molecules Absorbed on Glass Surface

    Institute of Scientific and Technical Information of China (English)

    JI Dong-Mei; HUANG Zheng-Xi; XIA An-Dong

    2005-01-01

    @@ We investigate the single molecule spectroscopy of chlorophyll a molecules on glass surface in N2-saturated environment. The basic photodynamic parameters of chlorophyll a molecules, such as fluorescence lifetime,survival time before photobleaching, on-time, and off-time, are reported. A four-level model is employed to describe the possible dynamics and photobleaching of chlorophyll a upon excitation. Broad distributions in fluorescence lifetimes and survival times are mainly due to the heterogeneities of both molecular conformation and local environment.

  5. Near infrared fluorescent chlorophyll nanoscale liposomes for sentinel lymph node mapping

    Directory of Open Access Journals (Sweden)

    Fan L

    2012-06-01

    Full Text Available Lina Fan,1,* Qiang Wu,1,* Maoquan Chu1,21School of Life Science and Technology, 2The Institute for Advanced Materials and Nano Biomedicine Tongji University, Shanghai, People's Republic of China *These authors contributed equally to this workBackground: Sentinel lymph node (SLN mapping using in vivo near infrared fluorescence imaging has attracted great attention during the past few years. Here we report on the early use of poorly water-soluble chlorophyll with near infrared fluorescence extracted from the leaf of Chimonanthus salicifolius, for mouse axillary SLN mapping.Methods and results: To improve the water solubility and SLN targeting of the chlorophyll, we encapsulated the chlorophyll in nanoscale liposomes. The liposome-coated chlorophyll nanocomposites obtained were spherical in shape and had an average diameter of 21.7 ± 6.0 nm. The nanocomposites dispersed well in water, and in aqueous suspension they exhibited brighter near infrared fluorescence than chlorophyll alone. After incubation of the nanocomposites with normal liver cells (QSG-7701 and macrophage cells (Ana-1 for no more than 48 hours, there was no obvious reduction in cell viability. When the nanocomposites were injected intradermally into the paw of a mouse, the axillary SLN was found to be strongly fluorescent and was easily visualized in real time without a requirement for surgery. The intensity of the near infrared fluorescence emitted by the SLN was obviously brighter than that emitted by the SLN of another mouse that had been intradermally injected with chlorophyll alone.Conclusion: Our data show that the liposome-coated chlorophyll nanocomposites could have great potential for clinical SLN mapping due to their lack of toxicity, bright near infrared fluorescence, and small diameter.Keywords: chlorophyll, liposomes, nanocomposites, near infrared fluorescence, sentinel lymph node mapping

  6. Qtl mapping of wheat doubled haploids for chlorophyll content and chlorophyll fluorescence kinetics under drought stress imposed at anthesis stage

    International Nuclear Information System (INIS)

    Drought stress is one of the major environmental constraints to crop plants including wheat worldwide. Synthetic hexaploid can act as a vehicle for improving crop tolerance against biotic and abiotic stresses. Doubled haploid population consisting of one hundred and forty individuals derived from cross of Opata and SH223 was used in the present study to identify genomic regions associated with various quantitative attributes of physiological nature. Doubled haploid mapping population was phenotyped for chlorophyll content and chlorophyll fluorescence kinetics under control and drought stress imposed at anthesis stage. Genotyping of population was accomplished by utilizing two hundred and sixty one polymorphic Gaterslaben wheat microsatellites and Beltsville agriculture research center simple sequence repeats. Linkage map of doubled haploid population comprising of 19 linkage groups and covering map length of two thousands six hundred and twenty six (2626) cM was constructed using map maker software. Major and minor QTLs associated with quantitative traits were identified using QGene software. Major QTL for chlorophyll content (QTc.wwc-1B-S11) of doubled haploid mapping population under anthesis drought stress was mapped on chromosome 1B and explained 10.09 percent of phenotypic variation at LOD score of 5.5. Seven major and minor QTLs for PCFK of doubled haploids were identified on chromosome 1B, 7A and 7D under control and drought stress at anthesis stage. The identified QTLs are of prime importance for high resolution mapping in synthetic hexaploid wheat. Genomic synteny of doubled haploids was observed with rice chromosome 2, 4, 7 and maize chromosome 7 owing to occurrence of orthologous QTLs for chlorophyll content and chlorophyll fluorescence respectively. (author)

  7. Chlorophyll fluorescence response to water and nitrogen deficit

    Science.gov (United States)

    Cendrero Mateo, Maria del Pilar

    The increasing food demand as well as the need to predict the impact of warming climate on vegetation makes it critical to find the best tools to assess crop production and carbon dioxide (CO2) exchange between the land and atmosphere. Photosynthesis is a good indicator of crop production and CO2 exchange. Chlorophyll fluorescence (ChF) is directly related to photosynthesis. ChF can be measured at leaf-scale using active techniques and at field-scales using passive techniques. The measurement principles of both techniques are different. In this study, three overarching questions about ChF were addressed: Q1) How water, nutrient and ambient light conditions determine the relationships between photosynthesis and ChF? Which is the optimum irradiance level for detecting water and nutrient deficit conditions with ChF? ; Q2) which are the limits within which active and passive techniques are comparable?; and Q3) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? To address these questions, two main experiments were conducted: Exp1) Concurrent photosynthesis and ChF light-response curves were measured in camelina and wheat plants growing under (i) intermediate-light and (ii) high-light conditions respectively. Plant stress was induced by (i) withdrawing water, and (ii) applying different nitrogen levels; and Exp2) coincident active and passive ChF measurements were made in a wheat field under different nitrogen treatments. The results indicated ChF has a direct relationship with photosynthesis when water or nitrogen drives the relationship. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Also, the results showed that for leaf-average-values, active measurements can be used to better understand the daily and seasonal behavior of passive ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a

  8. Induction of the 'in vivo' chlorophyll fluorescence excited by CW and pulse-periodical laser radiation

    International Nuclear Information System (INIS)

    Inductional changes of fluorescence of the native chlorophyll molecules in plant leaves excited by CW and pulse-periodical laser radiation are studied. The opportunity of controlling of the photosynthesis efficiency through fluorescence response at different rates of the electron flow in charge transfer chain of the photosynthetic apparatus of plant is shown. (author). 13 refs.; 4 refs

  9. A new indicator in early drought diagnosis of cucumber with chlorophyll fluorescence imaging

    Science.gov (United States)

    Wang, Heng; Li, Haifeng; Xu, Liang; Liu, Xu

    2015-05-01

    Crop population growth information can more fully reflect the state of crop growth, eliminate individual differences, and reduce error in judgment. We have built a suitable plant population growth information online monitoring system with the plant chlorophyll fluorescence and spectral scanning imaging to get the crop growth status. On the basis of the fluorescence image detection, we have studied the early drought diagnosis of cucumber. The typical chlorophyll fluorescence parameters can not reflect the drought degree significantly. We define a new indication parameter (DI). With the drought deepening, DI declines. DI can enlarge the early manifestation of cucumber drought (3-5 days), indicate more significantly in the early drought diagnosis of cucumber.

  10. 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).

  11. First observations of global and seasonal terrestrial chlorophyll fluorescence from space

    OpenAIRE

    Joiner, J.; A. P. Vasilkov; Y. Yoshida; Corp, L. A.; E. M. Middleton

    2011-01-01

    Remote sensing of terrestrial vegetation fluorescence from space is of interest because it can potentially provide global coverage of the functional status of vegetation. For example, fluorescence observations may provide a means to detect vegetation stress before chlorophyll reductions take place. Although there have been many measurements of fluorescence from ground- and airborne-based instruments, there has been scant information available from satellites. In this work...

  12. Chlorophyll a fluorescence lifetime reveals reversible UV-induced photosynthetic activity in the green algae Tetraselmis

    OpenAIRE

    Kristoffersen, Arne Skodvin; Hamre, Børge; Frette, Øyvind; Erga, Svein Rune

    2015-01-01

    The fluorescence lifetime is a very useful parameter for investigating biological materials on the molecular level as it is mostly independent of the fluorophore concentration. The green alga Tetraselmis blooms in summer, and therefore its response to UV irradiation is of particular interest. In vivo fluorescence lifetimes of chlorophyll a were measured under both normal and UV-stressed conditions of Tetraselmis. Fluorescence was induced by two-photon excitation using a femtosecond laser and ...

  13. MES16, a member of the methylesterase protein family, specifically demethylates fluorescent chlorophyll catabolites during chlorophyll breakdown in Arabidopsis.

    Science.gov (United States)

    Christ, Bastien; Schelbert, Silvia; Aubry, Sylvain; Süssenbacher, Iris; Müller, Thomas; Kräutler, Bernhard; Hörtensteiner, Stefan

    2012-02-01

    During leaf senescence, chlorophyll (Chl) is broken down to nonfluorescent chlorophyll catabolites (NCCs). These arise from intermediary fluorescent chlorophyll catabolites (FCCs) by an acid-catalyzed isomerization inside the vacuole. The chemical structures of NCCs from Arabidopsis (Arabidopsis thaliana) indicate the presence of an enzyme activity that demethylates the C13(2)-carboxymethyl group present at the isocyclic ring of Chl. Here, we identified this activity as methylesterase family member 16 (MES16; At4g16690). During senescence, mes16 leaves exhibited a strong ultraviolet-excitable fluorescence, which resulted from large amounts of different FCCs accumulating in the mutants. As confirmed by mass spectrometry, these FCCs had an intact carboxymethyl group, which slowed down their isomerization to respective NCCs. Like a homologous protein cloned from radish (Raphanus sativus) and named pheophorbidase, MES16 catalyzed the demethylation of pheophorbide, an early intermediate of Chl breakdown, in vitro, but MES16 also demethylated an FCC. To determine the in vivo substrate of MES16, we analyzed pheophorbide a oxygenase1 (pao1), which is deficient in pheophorbide catabolism and accumulates pheophorbide in the chloroplast, and a mes16pao1 double mutant. In the pao1 background, we additionally mistargeted MES16 to the chloroplast. Normally, MES16 localizes to the cytosol, as shown by analysis of a MES16-green fluorescent protein fusion. Analysis of the accumulating pigments in these lines revealed that pheophorbide is only accessible for demethylation when MES16 is targeted to the chloroplast. Together, these data demonstrate that MES16 is an integral component of Chl breakdown in Arabidopsis and specifically demethylates Chl catabolites at the level of FCCs in the cytosol. PMID:22147518

  14. Salt stress change chlorophyll fluorescence in mango Estresse salino altera a fluorescência da clorofila em mangueira

    OpenAIRE

    Cicero Cartaxo de Lucena; Dalmo Lopes de Siqueira; Hermínia Emilia Prieto Martinez; Paulo Roberto Cecon

    2012-01-01

    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 le...

  15. Effect of Phosphatidylcholine on the Steady State Fluorescence of Chlorophyll in Photosystem Ⅱ Particles

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Phosphatidylcholine (PC) accounts for less than 1% of the total lipids in plant photosystem II (PSII) particles.In this experiment, PSII particles were reconstituted with PC to construct PSII-PC vesicles.The effect of PC on the steady state fluorescence of chlorophyll (Chl) in PSII particles was studied.The results show that PC significantly affected the fluorescence intensity, but did not obviously affect the fluorescence emission band peak position.PC also did not obviously affect the absorbance at 436 nm or the amide I band peak position in FT-IR spectroscopy of PSII particles.The results suggest that PC may affect the light energy transfer from the antenna chlorophyll molecules to the reaction center chlorophyll molecule (P680).

  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. Chlorophyll fluorescence, Orbital and Photosynthesis: practical activities integrating concepts of Chemistry, Physics and Biology

    Directory of Open Access Journals (Sweden)

    Elgion Lucio da Silva Loreto

    2013-11-01

    Full Text Available These laboratory activities explore the relationship between the reserve of energy that occur during photosynthesis and the chlorophyll fluorescence emission when in solution as opposed to absence of fluorescence when the chlorophyll are in intact chloroplasts. This proposal can be used as short demo or as  activities with longer duration, to show chlorophyll's properties associated with the photosynthesis. The materials proposed for the implementation of the activities are simple, and possible to building it by the students, enabling the development of various skills and experimental proposals. The protocols are based on observations and record key questions to continue the execution. During the activities, questions promotes pauses for moments of reflection and review of concepts. At the end are presented and discussed proposals for development of interdisciplinary projects.

  18. Evaluation of chicory seeds maturity by chlorophyll fluorescence imaging

    OpenAIRE

    Ooms, David; Destain, Marie-France

    2011-01-01

    Chicory (Cichorium intybus L.) seed production includes sorting to remove foreign materials and non-viable seeds. A machine vision system was developed to monitor the fluorescence in order to detect the immature chicory seeds. It comprised a monochromatic light source, a highpass filter and a monochromatic CCD camera sensitive to red and infrared. With this device, blue light reflected by the seeds was blocked whilst red fluorescence was measured by the camera. A segmentation a...

  19. Near infrared fluorescent chlorophyll nanoscale liposomes for sentinel lymph node mapping

    OpenAIRE

    Fan L; Wu Q; Chu M

    2012-01-01

    Lina Fan,1,* Qiang Wu,1,* Maoquan Chu1,21School of Life Science and Technology, 2The Institute for Advanced Materials and Nano Biomedicine Tongji University, Shanghai, People's Republic of China *These authors contributed equally to this workBackground: Sentinel lymph node (SLN) mapping using in vivo near infrared fluorescence imaging has attracted great attention during the past few years. Here we report on the early use of poorly water-soluble chlorophyll with near infrared fluoresc...

  20. Forest productivity and water stress in Amazonia: observations from GOSAT chlorophyll fluorescence

    OpenAIRE

    J.-E. Lee; C. Frankenberg; C. van der Tol; J. A. Berry; Luis Guanter; C. K. Boyce; J. B. Fisher; E. Morrow; J. R. Worden; S. Asefi; G. Badgley; S. Saatchi

    2013-01-01

    It is unclear to what extent seasonal water stress impacts on plant productivity over Amazonia. Using new Greenhouse gases Observing SATellite (GOSAT) satellite measurements of sun-induced chlorophyll fluorescence, we show that midday fluorescence varies with water availability, both of which decrease in the dry season over Amazonian regions with substantial dry season length, suggesting a parallel decrease in gross primary production (GPP). Using additional SeaWinds Scatterometer onboard Qui...

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

    OpenAIRE

    Ladislav Nedbal; David Šebela; Chandra Bellasio; Radek Tesař; Julie Olejníčková

    2012-01-01

    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 an...

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

    OpenAIRE

    JULITTA Tommaso; Corp, Lawrence; Schickling, Anke; Colombo, Roberto; Rossini, Micol; Burkart, Andreas; COGLIATI Sergio; Davies, Neville; Hom, Milton; Mac Arthur, Alasdair; Middleton, Elizabeth; Rascher, Uwe

    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 m...

  3. Interactions between iron and titanium metabolism in spinach: A chlorophyll fluorescence study in hydropony

    Czech Academy of Sciences Publication Activity Database

    Cígler, Petr; Olejníčková, Julie; Hrubý, Martin; Cséfalvay, Ladislav; Peterka, J.; Kužel, S.

    2010-01-01

    Roč. 167, č. 18 (2010), s. 1592-1597. ISSN 0176-1617 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40500505; CEZ:AV0Z60870520 Keywords : chlorophyll fluorescence * iron * photosynthetic apparatus * spinach * titanium Subject RIV: CC - Organic Chemistry Impact factor: 2.677, year: 2010

  4. Control of electron transport processes in photosystem II by chlorophyll fluorescence parameters

    International Nuclear Information System (INIS)

    In this work the opportunity of the electron photosynthetic transport control in plant leaves by means of the prompt and delayed chlorophyll fluorescence are shown. Influence of environment conditions (temperature, water provision) is considered in respect to their limiting role in efficiency of the energy-transmutation processes in the photosynthetic apparatus. (author)

  5. 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.

  6. Chlorophyll fluorescence as an indicator of plant water status in cotton

    Science.gov (United States)

    Various methods exist for the measurement of plant water status. Plant breeders value methods that are fast and inexpensive lending themselves to the efficient evaluation of large segregating populations. Chlorophyll fluorescence is a parameter commonly measured by plant physiologists when studying ...

  7. Effects of Chlorophyll Availability on Fluorescence Components of Photosystems in the ORF469-Deletion Mutant of Cyanobacterium

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    PCR-amplified ORF469 fragment from Synechocystis sp.PCC 6803 was cloned into pUC118 and a construct was made in which part of ORF469 was deleted and replaced by erythromycin resistance cassette.Transformation of wild type strain of Synechocystis sp.PCC 6803 with this construct yielded a mutant in which ORF469 was deleted.In the resulting mutant, the light-independent pathway of chlorophyll biosynthesis was inactivated and availability of chlorophyll was fully dependent on light.When propagated the mutant in dark, the chlorophyll was non-detectable and protochlorophyllide with 645 nm fluorescence emission peak was accumulated.Meanwhile, the fluorescence emission peaks (excited at 435 nm) of thylakoids at 685 nm, 695 nm and 725 nm, which represented relative chlorophyll-binding proteins, disappeared.Upon return of dark-grown ORF469 mutant to the light, greening occurred and chlorophyll was synthesized to assembly fluorescence emission components in photosystems.Newly synthesized chlorophyll combined the fluorescence component of 685 nm at first, then 725 nm and 695 nm at last, which indicates a pecking order for biogenesis of chlorophyll-binding proteins when availability of chlorophyll is limited.The mutant lacking ORF469 in Synechocystis sp.PCC 6803 was suggested as an excellent cyanobacterial system for studies on the interactions between chlorophyll and chlorophyll-binding proteins in photosystems.

  8. Effects of lanthanum nitrate on growth and chlorophyll fluorescence characteristics of Alternanthera philoxeroides under perchlorate stress

    Institute of Scientific and Technical Information of China (English)

    谢寅峰; 蔡贤雷; 刘伟龙; 陶功胜; 陈倩; 张强

    2013-01-01

    To investigate the effects of exogenous lanthanum (La) on Alternanthera philoxeroides (Mart.) Griseb under perchlorate stress, changes in the growth and physiological parameters were investigated in solution culture experiments under controlled condi-tions. Different concentrations of La (NO3)3 were used in our study. It was shown that 0.1 and 0.5 mg/L La3+alleviated the inhibition effect of perchlorate on A. philoxeroides, including relative growth yield, dry weight of different organs, leaf area and root activity. And La3+prevented decline in the relative chlorophyll content and chlorophyll fluorescence parameters including Fv/Fm, Fv'/Fm',ΦPSI and ETR induced by perchlorate stress. Moreover, 0.5 mg/L La3+showed an optimal mitigative effect, while excess La3+(5.0 mg/L) led to synergistic effect on stress. Correlation analysis revealed a significant positive relationship between growth indexes and the chlorophyll fluorescence parameters, root activity and relative chlorophyll content (p<0.05). The results suggested that appropriate concentration of La3+could effectively alleviate growth inhibition and injury of A. philoxeroides caused by perchlorate stress, and the mitigative effect of La3+might be achieved by improving root activity, maintaining chlorophyll content and promoting photochemical efficiency of photosystem II of A. philoxeroides under perchlorate stress.

  9. [Monitoring of the Moskva River Water Using Microbiological Parameters and Chlorophyll a Fluorescence].

    Science.gov (United States)

    Mosharova, I V; Il'inskii, V V; Matorin, D N; Mosharov, S A; Akulova, A Yu; Protopopov, F F

    2015-01-01

    The results of investigations of three Moskva River sites with different degree of pollution using a complex of microbiological characteristics and the parameters of chlorophyll a fluorescence are presented. We determined that the bacterioplankton seasonal dynamics at less polluted waters (Tushino and Vorobyovy Gory) were similar and differed significantly from one in more polluted waters (Dzerzhinskii). The number of bacteria with active electron transport chain, as well as their share in the bacterioplankton structure, was higher in the water of Dzerzhinskii (average annual values of 0.23 x 10(6) cells/mL and 14%), that in the less polluted water of Tushino and Vorobyovy Gory (0.14 x 10(6) cells/mL; 6% and 0.15 x 10(6) cells/mL; 7%, respectively). From April to October, the content of chlorophyll a and its photosynthetic activity were the highest in Tushino. In Dzerzhinskii, during spring the increase in photosynthetic activity commenced earlier and was more intensive that the increase in chlorophyll a content, i.e., the increase in phytoplankton biomass was temporarily suppressed. We suggest association of this phenomenon with suppression of organic matter synthesis by phytoplankton due to the high water pollution in Dzerzhinskii. The second autumn peak of chlorophyll a content, that was typical of clear water and was observed in Tushino, did not occur in Dzerzhinskii. We recommend combined application of these microbiological parameters and characteristics of chlorophyll a fluorescence for a monitoring. PMID:26964361

  10. 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

  11. Movement influences carambola leaflet chlorophyll fluorescence and temperature under sunny conditions

    International Nuclear Information System (INIS)

    Leaflets of 'Arkin', 'B-10', 'Kary', and 'Sri Kembangan' carambola (Averrhoa carambola L.) trees were restrained in a horizontal position for 3.5 h during midday under full sun conditions to determine the influence of overriding natural leaflet movement on adaxial chlorophyll fluorescence and temperature. Induced chlorophyll fluorescence obtained after 30 minutes of dark adaptation following the period of full sun exposure was affected by leaflet movement. Restrained leaflets exhibited a variable fluorescence (Fv)/peak fluorescence (Fm) of 0.48, while that of unrestrained leaflets was 0.65. Adaxial leaflet temperature of restrained leaflets was 6C higher than that of leaflets that were allowed to move. The influence of leaflet movement on temperature or chlorophyll fluorescence was not different among the four cultivars. However, mean Fv/Fm of 'Kary' and 'Sri Kembangan' was lower than that of 'B-10'. Our results indicate that the ability of carambola to change leaflet angle leads to lower temperature and higher photochemical efficiency than occurs when leaflets are not allowed to move naturally (vertically orient) under full sun conditions

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

    Directory of Open Access Journals (Sweden)

    H. Lavigne

    2011-12-01

    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 represents 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 operate routinely on oceanographic cruise since the seventies. Nevertheless, fluorescence is only a proxy of the Total Chlorophyll-a concentration and a data calibration is required. Calibration issues are, however, source 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 data bases exist. Consequently, merged estimations with other data sources (i.e. 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 color observation. The method is close to the approach proposed by Boss et al. (2008 to calibrate 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, which resulted to be of about 31 %. Comparison with the Boss et al. (2008 method, carried out on a subset of the DYFAMED data set simulating a profiling float

  13. 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

  14. 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

  15. Chlorophyll Fluorescence Spectra as an Indicator of X-Ray + EMS-Induced Phytotoxicity in Safflower

    OpenAIRE

    Pandey, Jitendra Kumar; Srivastava, Preeti; Yadav, Ram Singh; Gopal, Ram

    2012-01-01

    The present investigation deals with the study of in vivo laser-induced chlorophyll florescence spectra (LICF) of safflower leaves (Carthamus tinctorius L.) for X-rays + EMS-treated plants. Seeds were treated with different doses of X-ray + EMS (5, 8, 12, 25, and 30 Kr + 0.5% EMS) and were grown in the green house. The effects of the concerned treatment on chlorophyll (Chl) contents and Chl fluorescence were investigated after 7 days of germination. Results obtained revealed that the values o...

  16. Use of blue-green and chlorophyll fluorescence measurements for differentiation between nitrogen deficiency and pathogen infection in winter wheat.

    Science.gov (United States)

    Bürling, Kathrin; Hunsche, Mauricio; Noga, Georg

    2011-09-15

    In recent years, several sensor-based approaches have been established to early detect single plant stresses, but the challenge of discriminating between simultaneously occurring stressors still remains. Earlier studies on wheat plants strongly affected by pathogens and nitrogen deficiency indicated that chlorophyll fluorescence might be suited to distinguish between the two stressors. Nevertheless, there is lack of information on the pre-symptomatic detection of synchronized occurrence of slight N-deficiency and the early stages of pathogen infection. The usefulness of the blue, green, and yellow fluorescence signals in this context has not yet been explored. We hypothesized that differentiation between wheat plants' physiological reaction due to N-deficiency and leaf rust (Puccinia triticina) as well as N-deficiency and powdery mildew (Blumeria graminis f. sp. tritici) might be accomplished by means of UV laser-induced fluorescence spectral measurements between 370 and 620nm in addition to chlorophyll fluorescence (640-800nm). Plants were provided with either a normal or a modified Hoagland nutrient solution in order to induce a slight N deficit. Pathogen inoculation was carried out on the second fully developed leaf. Four experimental groups were evaluated: (a) N-full-supply [N+]; (b) N-deficiency [N-]; (c) N-full-supply+pathogen [N+/LR] or [N+/PM]; (d) N-deficiency+pathogen [N-/LR] or [N-/PM]. The results revealed that, in addition to the amplitude ratio of R/FR fluorescence, B/G fluorescence also facilitated reliable and robust discrimination among the four experimental groups. The discrimination among the experimental groups was accomplished as early as one and two days after inoculation for powdery mildew and leaf rust infection, respectively. During the 3days evaluation period, the differences among the treatment groups became more evident. Moreover, several other amplitude ratios and half-bandwidth ratios proved to be suited to early detect fungal

  17. A Passive Method for Detecting Vegetation Stress from Orbit: Chlorophyll Fluorescence Spectra from Fraunhofer Lines

    Science.gov (United States)

    Theisen, Arnold F.

    2000-01-01

    Solar-stimulated chlorophyll fluorescence measured with the Fraunhofer line depth method has correlated well with vegetation stress in previous studies. However, the instruments used in those studies were limited to a single solar absorption line (e.g. 656.3 nm), obviating the red/far-red ratio (R/FR) method. Optics and detector technology have reached the level whereby multiple, very narrow Fraunhofer lines are resolvable. Thirteen such lines span the visible spectrum in the red to far-red region where chlorophyll fluorescence occurs. Fluorescence intensities at the 13 Fraunhofer line wavelengths were used to model emission spectra. The source data were collected for summer and fall bean crops (Phaseolus vulgaris L.) subjected to various levels of nitrogen fertilization. The intensities were adjusted to account for Fraunhofer line depth and atmospheric transmittance. Multiple R/FR fluorescence ratios, calculated from the modeled fluorescence spectra, correlated strongly with leaf chlorophyll concentration and well with applied nitrogen. The ratio yielding the best correlation with chlorophyll utilized red fluorescence at the 694.5 nm Fraunhofer line and farred fluorescence at the 755.6 nm Fraunhofer line. Twenty R/FR ratios, each evaluated for the maximum differential between low and high (optimal) nitrogen treatments, ranked higher in some cases and lower in others, possibly related to the time of year the crops were grown and the stage of growth of the crops. Ratios with 728.9 nm and 738.9 nm in the denominator consistently ranked in the lowest and next lowest quartile, respectively. Ratios of the 656.3 nm Fraunhofer line and the 755.6 nm line consistently ranked highest for the summer crop. Ratios with 755.6 nm in the denominator ranked in the upper quartile for 10 out of 12 measurement dates. Differences in ratio ranking indicate that physiological conditions may be estimated using selected ratios of Fraunhofer lines within the context of R/FR analysis. A

  18. 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.

  19. Leaf Level Chlorophyll Fluorescence Emission Spectra: Narrow Band versus Full 650-800 nm Retrievals

    Science.gov (United States)

    Middleton, E.; Zhang, Q.; Campbell, P. K.; Huemmrich, K. F.; Corp, L.; Cheng, Y.

    2012-12-01

    Recently, chlorophyll fluorescence (ChlF) retrievals in narrow spectral regions (sample the total full-spectrum ChlF and are made at non-optimal wavelengths since they are not located at the peak fluorescence emission features. We wish to estimate the total full-spectrum ChlF based on emissions obtained at selected wavelengths. For this, we drew upon leaf emission spectra measured on corn leaves obtained from a USDA experimental cornfield in MD (USA). These emission spectra were determined for the adaxial and abaxial (i.e., top and underside) surfaces of leaves measured throughout the 2008 and 2011 growing seasons (n>400) using a laboratory instrument (Fluorolog-3, Horiba Scientific, USA), recorded in either 1 nm or 5 nm increments with monochromatic excitation wavelengths of either 532 or 420 nm. The total ChlF signal was computed as the area under the continuous spectral emission curves, summing the emission intensities (counts per second) per waveband. The individual narrow (1 or 5 nm) waveband emission intensities were linearly related to full emission values, with variable success across the spectrum. Equations were developed to estimate total ChlF from these individual wavebands. Here, we report the results for the average adaxial/abaxial emissions. Very strong relationships were achieved for the relatively high fluorescence intensities at the red chlorophyll peak, centered at 685 nm (r2= 0.98, RMSE = 5.53 x 107 photons/s) and in the nearby O2-B atmospheric absorption feature centered at 688 nm (r2 = 0.94, RMSE = 4.04 x 107), as well as in the far-red peak centered at 740 nm (r2=0.94, RMSE = 5.98 x107). Very good retrieval success occurred for the O2-A atmospheric absorption feature on the declining NIR shoulder centered at 760 nm (r2 = 0.88, RMSE = 7.54 x 107). When perfect retrievals were assumed (0% noise), retrievals remained good in the low emission regions on either side of the peaks-- those associated with the H alpha line at 655 nm (r2 = 0.83, RMSE =8

  20. 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.

    OpenAIRE

    Leupold, Dieter; Teuchner, Klaus; Ehlert, Jürgen; Irrgang, Klaus-Dieter; Renger, Gernot; Lokstein, Heiko

    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(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 charact...

  1. Retrieval of aerosol parameters from the oxygen A band in the presence of chlorophyll fluorescence

    Directory of Open Access Journals (Sweden)

    A. F. J. Sanders

    2013-10-01

    Full Text Available We have investigated the precision of retrieved aerosol parameters for a generic aerosol retrieval algorithm over vegetated land using the O2 A band. Chlorophyll fluorescence is taken into account in the forward model. Fluorescence emissions are modeled as isotropic contributions to the upwelling radiance field at the surface and they are retrieved along with aerosol parameters. Precision is calculated by propagating measurement errors and a priori errors, including model parameter errors, using the forward model's derivatives. Measurement errors consist of noise and calibration errors. The model parameter errors considered are related to the single scattering albedo, surface pressure and temperature profile. We assume that measurement noise is dominated by shot noise; thus, results apply to grating spectrometers in particular. We describe precision for various atmospheric states, observation geometries and spectral resolutions of the instrument in a number of retrieval simulations. These precision levels can be compared with user requirements. A comparison of precision estimates with the literature and an analysis of the dependence on the a priori error in the fluorescence emission indicate that aerosol parameters can be retrieved in the presence of chlorophyll fluorescence: if fluorescence is present, fluorescence emissions should be included in the state vector to avoid biases in retrieved aerosol parameters.

  2. Retrieval of aerosol parameters from the oxygen A band in the presence of chlorophyll fluorescence

    Science.gov (United States)

    Sanders, A. F. J.; de Haan, J. F.

    2013-10-01

    We have investigated the precision of retrieved aerosol parameters for a generic aerosol retrieval algorithm over vegetated land using the O2 A band. Chlorophyll fluorescence is taken into account in the forward model. Fluorescence emissions are modeled as isotropic contributions to the upwelling radiance field at the surface and they are retrieved along with aerosol parameters. Precision is calculated by propagating measurement errors and a priori errors, including model parameter errors, using the forward model's derivatives. Measurement errors consist of noise and calibration errors. The model parameter errors considered are related to the single scattering albedo, surface pressure and temperature profile. We assume that measurement noise is dominated by shot noise; thus, results apply to grating spectrometers in particular. We describe precision for various atmospheric states, observation geometries and spectral resolutions of the instrument in a number of retrieval simulations. These precision levels can be compared with user requirements. A comparison of precision estimates with the literature and an analysis of the dependence on the a priori error in the fluorescence emission indicate that aerosol parameters can be retrieved in the presence of chlorophyll fluorescence: if fluorescence is present, fluorescence emissions should be included in the state vector to avoid biases in retrieved aerosol parameters.

  3. 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

  4. DIFFERENTIAL RESPONSES OF SEVEN CONTRASTING SPECIES TO HIGH LIGHT USING PIGMENT AND CHLOROPHYLL A FLUORESCENCE

    OpenAIRE

    Mittal S; Kumari, N.; Sharma, V.

    2011-01-01

    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 ecophys...

  5. Chlorophyll fluorescence quenching as a tool to screen olive cultivars tolerant to drought stress

    OpenAIRE

    Faraloni, Cecilia; Cutino, Ilaria; Petruccelli, Raffaella; Leva, Anna Rita; Traversi, Maria Laura; Torzillo, Giuseppe

    2009-01-01

    The measurements of fluorescence chlorophyll is considered a promising technique to rapidly quantify the response to physiological stress in higher plants. Drought stress can be considered one of the most frequent environmental constraints causing the failure of newly planted trees. Olive tree (Olea europaea), a representative drought stress tolerant plant, is one of the most typical and economically relevant plant species grown in the Mediterranean area. However, as different cultivars may e...

  6. Chlorophyll fluorescence emission can screen cold tolerance of cold acclimated Arabidopsis thaliana accessions

    Czech Academy of Sciences Publication Activity Database

    Mishra, Anamika; Heyer, A. G.; Mishra, Kumud

    2014-01-01

    Roč. 10, č. 38 (2014). ISSN 1746-4811 R&D Projects: GA MŠk EE2.3.20.0246; GA MŠk 7E12047 Institutional support: RVO:67179843 Keywords : high-throughput screening * chlorophyll a fluorescence transients * cold tolerance * cold acclimation * whole plant * Arabidopsis thaliana Subject RIV: EH - Ecology, Behaviour Impact factor: 3.102, year: 2014

  7. Co-registration of chlorophyll fluorescence emission and 3D models of plants

    Czech Academy of Sciences Publication Activity Database

    Ryba, Tomáš; Železný, Miloš

    Brno : Global change research centre, Academy of Sciences of the Czech Republic, v. v. i, 2013 - (Stojanov, R.; Žalud, Z.; Cudlín, P.; Farda, A.; Urban, O.; Trnka, M.), s. 264-267 ISBN 978-80-904351-8-6. [Global Change and Resilience. Brno (CZ), 22.05.2013-24.05.2013] Institutional support: RVO:67179843 Keywords : chlorophyll fluorescence * 3D model of plant * co- registration * image registration * calibration object Subject RIV: EH - Ecology, Behaviour

  8. 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

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

    OpenAIRE

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

    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 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 lan...

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

    OpenAIRE

    Xijia Zhou; Zhigang Liu; Shan Xu; Weiwei Zhang; Jun Wu

    2016-01-01

    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 ...

  11. 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

  12. 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 approxim

  13. 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

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

    Science.gov (United States)

    García-Sánchez, M A; Serratos, I N; Sosa, R; Tapia-Esquivel, T; González-García, F; Rojas-González, F; Tello-Solís, S R; Palacios-Enriquez, A Y; Esparza Schulz, J M; Arrieta, A

    2016-01-01

    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 physicochemical

  15. Analysis of in vivo chlorophyll fluorescence spectra to monitor physiological state of tomato plants growing under zinc stress.

    Science.gov (United States)

    Cherif, Jaouhra; Derbel, Najoua; Nakkach, Mohamed; Bergmann, Hubertus von; Jemal, Fatma; Lakhdar, Zohra Ben

    2010-12-01

    The effects of zinc (Zn) on plant chlorophyll fluorescence were investigated in 10-day-old tomato (Solanum lycopersicum) seedlings subjected for 7 days to a series of zinc (10, 50, 100 and 150μM) applied via the nutrient solution. The chlorophyll fluorescence spectra of leaves were recorded in the spectral region 650-800nm using the spectroscopic technique of ultraviolet light emitting diode induced fluorescence spectroscopy (UV-LED IFS). These spectra have been used to analyze the effect of several doses of zinc on the photosynthetic activities of tomato plants. The fluorescence intensity ratios (FIR) at the two maxima (F(690)/F(735)) of control as well as treated tomato plants were calculated by evaluating curve-fitted parameters using a Gaussian spectral function. The variable chlorophyll fluorescence decrease ratio (R(Fd)) values were determined from the fluorescence induction kinetics curves recorded at 690nm and 735nm. In addition, Zn accumulation in plants, plant growth, photosynthetic pigments content and malondialdehyde level (MDA, an index of lipid peroxidation) were also estimated. The results indicated that the plants treated with 10μM of zinc exhibited better growth, however, higher concentrations of zinc were harmful for plants. Excess Zn induced a decrease in the R(Fd) values, which was associated with a strong decline of the total chlorophylls content and an increase of MDA level. The total chlorophylls content decline could also be followed via an increase of the chlorophyll fluorescence ratio F(690)/F(735). PMID:20829059

  16. 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)

  17. Analysis of Red and Far-Red Sun-Induced Chlorophyll Fluorescence and Their Ratio in Different Canopies Based on Observed and Modeled Data

    Directory of Open Access Journals (Sweden)

    Micol Rossini

    2016-05-01

    Full Text Available Sun-induced canopy chlorophyll fluorescence in both the red (FR and far-red (FFR regions was estimated across a range of temporal scales and a range of species from different plant functional types using high resolution radiance spectra collected on the ground. Field measurements were collected with a state-of-the-art spectrometer setup and standardized methodology. Results showed that different plant species were characterized by different fluorescence magnitude. In general, the highest fluorescence emissions were measured in crops followed by broadleaf and then needleleaf species. Red fluorescence values were generally lower than those measured in the far-red region due to the reabsorption of FR by photosynthetic pigments within the canopy layers. Canopy chlorophyll fluorescence was related to plant photosynthetic capacity, but also varied according to leaf and canopy characteristics, such as leaf chlorophyll concentration and Leaf Area Index (LAI. Results gathered from field measurements were compared to radiative transfer model simulations with the Soil-Canopy Observation of Photochemistry and Energy fluxes (SCOPE model. Overall, simulation results confirmed a major contribution of leaf chlorophyll concentration and LAI to the fluorescence signal. However, some discrepancies between simulated and experimental data were found in broadleaf species. These discrepancies may be explained by uncertainties in individual species LAI estimation in mixed forests or by the effect of other model parameters and/or model representation errors. This is the first study showing sun-induced fluorescence experimental data on the variations in the two emission regions and providing quantitative information about the absolute magnitude of fluorescence emission from a range of vegetation types.

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

    International Nuclear Information System (INIS)

    The aggregation dependent correlation between fluorescence quenching and the electronic carotenoid-chlorophyll interactions, φCouplingCar S1-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 φCouplingCar S1-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.

  19. Remote sensing of chlorophyll a fluorescence of vegetation canopies. 1. Near and far field measurement techniques

    International Nuclear Information System (INIS)

    This article presents instruments and techniques, used in several vegetation monitoring experiments. Simultaneous monitoring was performed with different approaches, including fluorescence lidar and passive remote sensing, leaf level reflectance, and laser fluorimetry, and compared with physiological measurements. Most of the instrumentation described was designed and built for this application. Experiments were carried out in the laboratory and in the field, to investigate the relationship between chlorophyll fluorescence spectra and plant ecophysiology. Remote sensing, spectroscopy, and ecophysiology data were then collected by an intensive research team, joining different experiences and working in national and international projects

  20. 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

    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...

  1. 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. PMID:25150973

  2. Measurement of chlorophyll a fluorescence with an airborne fluorosensor

    Science.gov (United States)

    Jarrett, O., Jr.; Brown, C. A., Jr.; Campbell, J. W.; Houghton, W. M.; Poole, L. R.

    1979-01-01

    Phytoplankton biomass and diversity among various algal species are important for marine productivity assessments. The spatial heterogeneity of phytoplankton in coastal and estuarine environments complicates estimates of total biomass using conventional surface sampling techniques. Since synoptic or near-synoptic data can be quite useful in these studies, this area is a natural focal point for development of remote sensors. However, it is very difficult to sense phytoplankton density and diversity with spacecraft-borne passive sensors primarily because modulation in the signal due to phytoplankton is of the same order as that of atmospheric effects. The same sensors mounted on aircraft may be able to detect and quantify high concentrations of phytoplankton (blooms), but the current lack of knowledge about the spectral reflectance signatures of the major phytoplankton color groups rules out any diversity measurements by this type of sensor. An active fluorosensor mounted on a low-flying aircraft or helicopter is not limited by any of these constraints. A brief survey of the four currently active systems is presented.

  3. 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.

  4. Use of O-J-I-P Chlorophyll Fluorescence Transients to Probe Multiple Effects of UV-C Radiation on the Photosynthetic Apparatus of Euglena

    Directory of Open Access Journals (Sweden)

    Chalinda Koshitha Beneragama

    2014-12-01

    Full Text Available Although the kinetic chlorophyll fluorescence signals are rich in information, most of the chlorophyll fluorescence related studies deal only with the quantum yield of primary photochemistry (Fv/Fm. JIP-test based OJIP fluorescence transient analysis is relatively a new technique to investigate the environmental stress responses of photosynthetic organisms. In the present study, the deleterious effects of ultraviolet (UV radiation on the photosynthetic machinery were probed by the JIP-test in Euglena, one of the most potent organisms for the future space stations. The cells were exposed to a series of UV-C doses and immediately after exposure, survival percentage was determined with Neutral Red staining, and the chlorophyll fluorescence was measured using AquaPen AP-C 100 fluorometer. Resultant OJIP transients were analyzed according to JIP-test, and several functional and structural parameters were derived to explain the PSII behavior. Results indicated that the UV-C induced inhibition of electron transport is severely affected due to higher sensitivity of dark reactions after QA -, represented as ψo, the electron transfer probability, than of the light dependent reactions, represented as φPo, the trapping probability. The performance index (PIABS of PSII, which is a combination of the indices of three independent parameters, decreased markedly in exponential manner in response to UVC. Results illustrate the advantage of using a number of fluorescent parameters over the use of one parameter, often the Fv/Fm.

  5. The Use of Chlorophyll Fluorescence Lifetime to Assess Phytoplankton Physiology within a River-Dominated Environment

    Science.gov (United States)

    Hall, Callie M.; Miller, Richard L.; Redalje, Donald G.; Fernandez, Salvador M.

    2002-01-01

    Chlorophyll a fluorescence lifetime was measured for phytoplankton populations inhabiting the three physical zones surrounding the Mississippi River's terminus in the Gulf of Mexico. Observations of river discharge volume, nitrate + nitrite, silicate, phosphate, PAR (Photosynthetically Active Radiation) diffuse attenuation within the water column, salinity, temperature, SPM, and chl a concentration were used to characterize the distribution of chl fluorescence lifetime within a given region within restricted periods of time. 33 stations extending from the Mississippi River plume to the shelf break of the Louisiana coast were surveyed for analysis of chlorophyll fluorescence lifetime during two cruises conducted March 31 - April 6, 2000, and October 24 - November 1, 2000. At each station, two to three depths were chosen for fluorescence lifetime measurement to represent the vertical characteristics of the water column. Where possible, samples were taken from just below the surface and from just above and below the pycnocline. All samples collected were within the 1% light level of the water column (the euphotic zone). Upon collection, samples were transferred to amber Nalgene bottles and left in the dark for at least 15 minutes to reduce the effects of non-photochemical quenching and to insure that photosynthetic reaction centers were open. Before measurements within the phase fluorometer were begun, the instrument was allowed to warm up for no less than one hour.

  6. Error in interpreting field chlorophyll fluorescence measurements: heat gain from solar radiation

    International Nuclear Information System (INIS)

    Temperature and chlorophyll fluorescence characteristics were determined on leaves of various horticultural species following a dark adaptation period where dark adaptation cuvettes were shielded from or exposed to solar radiation. In one study, temperature of Swietenia mahagoni (L.) Jacq. leaflets within cuvettes increased from approximately 36C to approximately 50C during a 30-minute exposure to solar radiation. Alternatively, when the leaflets and cuvettes were shielded from solar radiation, leaflet temperature declined to 33C in 10 to 15 minutes. In a second study, 16 horticultural species exhibited a lower variable: maximum fluorescence (Fv:Fm) when cuvettes were exposed to solar radiation during the 30-minute dark adaptation than when cuvettes were shielded. In a third study with S. mahagoni, the influence of self-shielding the cuvettes by wrapping them with white tape, white paper, or aluminum foil on temperature and fluorescence was compared to exposing or shielding the entire leaflet and cuvette. All of the shielding methods reduced leaflet temperature and increased the Fv:Fm ratio compared to leaving cuvettes exposed. These results indicate that heat stress from direct exposure to solar radiation is a potential source of error when interpreting chlorophyll fluorescence measurements on intact leaves. Methods for moderating or minimizing radiation interception during dark adaptation are recommended. (author)

  7. Quenching action of monofunctional sulfur mustard on chlorophyll fluorescence: towards an ultrasensitive biosensor.

    Science.gov (United States)

    Kaur, Simerjit; Singh, Minni; Flora, Swaran Jeet Singh

    2013-11-01

    An ultrasensitive fluorimetric biosensor for the detection of chemical warfare agent sulfur mustard (SM) was developed using its monofunctional analogue. SM is a vesicant and a potent chemical threat owing to its direct toxic effects on eyes, lungs, skin and DNA. This work investigates the quenching action of the analyte on chlorophyll fluorescence as elucidated by nuclear magnetic resonance, Fourier transform infrared spectroscopy and mass spectrometry studies suggesting the electrophilic attack of carbonium ion on nitrogens of the porphyrin moiety of chlorophyll. The properties of immobilisation matrix were optimised and scanning electron microscope observations confirmed improvement in pore size of sol-gels by addition of 32 % (v/v) glycerol, a feature enabling enhanced sensitivity towards the analyte. Chlorophyll embedded sol-gel was treated with increasing concentrations of monofunctional SM and the corresponding drop in maximum fluorescence intensity as measured by emission at 673 nm was observed, which varied linearly and had a detection limit of 7.68 × 10(-16) M. The biosensor was found to be 6 orders of magnitude more sensitive than the glass microfibre-based disc biosensor previously reported by us. PMID:23955347

  8. Xanthophyll cycle-dependent quenching of photosystem II chlorophyll a fluorescence: formation of a quenching complex with a short fluorescence lifetime.

    OpenAIRE

    Gilmore, A M; Hazlett, T. L.; Govindjee

    1995-01-01

    Excess light triggers protective nonradiative dissipation of excitation energy in photosystem II through the formation of a trans-thylakoid pH gradient that in turn stimulates formation of zeaxanthin and antheraxanthin. These xanthophylls when combined with protonation of antenna pigment-protein complexes may increase nonradiative dissipation and, thus, quench chlorophyll a fluorescence. Here we measured, in parallel, the chlorophyll a fluorescence lifetime and intensity to understand the mec...

  9. 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

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

    Science.gov (United States)

    Zhou, Xijia; Liu, Zhigang; Xu, Shan; Zhang, Weiwei; Wu, Jun

    2016-01-01

    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

  11. 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

  12. Relationship between the Fluorescence Lifetime of Chlorophyll 'a' and Primary Productivity within the Mississippi River Plume and Adjacent Shelf Region

    Science.gov (United States)

    Hall, Callie; Miller, Richard L.; Fernandez, Salvador M.; McKee, Brent A.

    2000-01-01

    In situ measurements of chlorophyll fluorescence intensity have been widely used to estimate phytoplankton biomass. However, because the fluorescence quantum yield of chlorophyll a in vivo can be highly variable, measurements of chlorophyll fluorescence intensity cannot be directly correlated with phytoplankton biomass and do not provide information on the physiological state of the phytoplankton under study. Conversely, lifetime-based measurements of chlorophyll fluorescence provide a framework in which photosynthetic rates of phytoplankton can be analyzed according to phytoplankton physiology. Along with the measurement of primary production and ambient nutrient concentrations within the Mississippi River plume in the northern Gulf of Mexico, phytoplankton fluorescence lifetimes were measured using a Fluorescence Lifetime Phytoplankton Analyzer (developed under a NASA Small Business Innovative Research contract to Ciencia, Inc.). Variability of fluorescence lifetimes within the plume can be used as a background from which to interpret variations in the maximum quantum yield of photochemistry. The extent to which nutrient and effluent loading in this dynamic coastal area affect the photosynthetic performance of phytoplankton will be presented as a function of phytoplankton fluorescence lifetimes.

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

    OpenAIRE

    François Perreault; Abdallah Oukarroum; Laura Pirastru; Louka Sirois; William Gerson Matias; Radovan Popovic

    2010-01-01

    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 ...

  14. High night temperature-induced accelerated maturation of rice panicles can be detected by chlorophyll fluorescence

    Czech Academy of Sciences Publication Activity Database

    Šebela, David; Quiňones, C.; Olejníčková, Julie; Jagadish, K. S. V.

    Brno: Global Change Research Centre, The Czech Academy of Sciences, v. v. i., 2015 - (Urban, O.; Šprtová, M.; Klem, K.), s. 134-137 ISBN 978-80-87902-10-3. [Global Change: A Complex Challenge /4th/. Brno (CZ), 23.03.2015-24.03.2015] R&D Projects: GA MŠk EE2.3.20.0246; GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : temperature * chlorophyll fluorescence Subject RIV: EH - Ecology, Behaviour

  15. Evaluation of Chlorophyll Content and Fluorescence Parameters as Indicators of Drought Tolerance in Barley

    Institute of Scientific and Technical Information of China (English)

    LI Rong-hua; GUO Pei-guo; Michael Baum; Stefania Grando; Salvatore Ceccarelli

    2006-01-01

    Drought is a major abiotic stress that severely affects food production worldwide. Agronomic and physiological traits associated with drought tolerance are suitable indicators for selection of drought tolerance genotypes to reduce the impact of water deficit on crop yield in breeding program. The objective of this study was to identify indicators related to drought tolerance through analysis of photosynthetic traits in barley (Hordeum vulgare L.). These traits included chlorophyll content, initial fluorescence (Fo), maximum primary yield of photochemistry of pho tosystem Ⅱ (Fv / Fo) and maximum quantum yield of photosystem Ⅱ (Fv/Fm). Four genotypes (Tadmor, Arta, Morocco9-75 and WI2291) variable in drought tolerance were used to investigate the correlation between these traits and drought tolerance. The results reflected that all of these traits were affected negatively in the four genotypes at different levels of post-anthesis drought stress, but the decrease in drought tolerant genotypes was much less than that of drought sensitive genotypes. The results further revealed that the components of the photosynthetic apparatus could be damaged significantly in drought sensitive genotypes, while drought tolerant genotypes were relatively less affected. On the other hand, the values of chlorophyll content, Fo, Fv/Fo and Fv/Fm in drought tolerance genotypes were significantly higher than those in drought sensitive genotypes under drought stress. It was concluded that chlorophyll content, Fo, Fv / Fo and Fv / Fm could be considered as reliable indicators in screening barley germplasm for drought tolerance.

  16. Vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: a first database for the global ocean

    OpenAIRE

    R. Sauzède; Lavigne, H.; Claustre, H.; J. Uitz; C. Schmechtig; F. D'Ortenzio; Guinet, C.; Pesant, S.

    2015-01-01

    In vivo chlorophyll a fluorescence is a proxy of chlorophyll a concentration, and is one of the most frequently measured biogeochemical properties in the ocean. Thousands of profiles are available from historical databases and the integration of fluorescence sensors to autonomous platforms has led to a significant increase of chlorophyll fluorescence profile acquisition. To our knowledge, this important source of environmental data has not yet been included in global analyse...

  17. Vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: a first database for the global ocean

    OpenAIRE

    R. Sauzède; Lavigne, H.; Claustre, H.; J. Uitz; C. Schmechtig; F. D'Ortenzio; Guinet, C.; Pesant, S.

    2015-01-01

    In vivo chlorophyll a fluorescence is a proxy of chlorophyll a concentration, and is one of the most frequently measured biogeochemical properties in the ocean. Thousands of profiles are available from historical databases and the integration of fluorescence sensors to autonomous platforms led to a significant increase of chlorophyll fluorescence profile acquisition. To our knowledge, this important source of environmental data has not yet been included in global analyses. A total o...

  18. 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.

  19. 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).

  20. Application of Chlorophyll Fluorescence Imaging Technology for Fresh Quality Control of Grape Fruit Preserved Under Different Storage Conditions

    OpenAIRE

    Sung Yung Yoo; Sok Samait; Jong Yong Park; Tae Wan Kim

    2014-01-01

    The objective of this study was to find a rapid determination of the freshness of grape (Vitis vinifera. L.) fruits using portable chlorophyll fluorescence imaging instrument. To assess the fresh quality of grape fruits, an imaging technique of the photochemical responses of pericarp of grape fruit was performed with fruits preserved under the different storage conditions. The observed chlorophyll imaging photos were numerically transformed to the photochemical parameters on the basis of chlo...

  1. Seaglider observations of variability in daytime fluorescence quenching of chlorophyll-a in Northeastern Pacific coastal waters

    OpenAIRE

    B. S. Sackmann; M.J. Perry; C. C. Eriksen

    2008-01-01

    The use of new autonomous and Lagrangian platforms (e.g. gliders, drifters, etc.) has revolutionized sampling of the ocean. The incorporation of in vivo chlorophyll-a fluorometers into these platforms for characterizing chlorophyll-a concentrations and phytoplankton biomass has reinforced the need for a thorough understanding of the variability and biases associated with basic fluorescence measurements. Seaglider, a long-range autonomous glider, has been deployed routinely i...

  2. Measurement of leaf epidermal transmittance of UV radiation by chlorophyll fluorescence

    International Nuclear Information System (INIS)

    In higher plants one of the important functions of the leaf epidermis is the effective screening of ultraviolet-B (280–320 nm, UV-B) radiation, due mostly to phenolic compounds. The assessment of the contribution of this function is necessary for an evaluation of the impact of increasing UV-B radiation. A method is proposed to estimate epidermal transmittance on the basis of chlorophyll fluorescence measurements. Fluorescence of chlorophyll induced by UV-A (320–400 nm, measuring beam centered at 366 nm, half band width 32 nm) or UV-B (measuring beam centered at 314 nm, half band width 18 nm) is compared to that induced by a blue-green measuring light (475 nm, half band width 140 nm). It is shown that the ratios of UV-and blue-green (BG)-induced fluorescence, F(UV-A)/F(BG) and F(UV-B)/F(BG), are relatively constant among leaf samples of various species (Vicia faba, Spinacia oleracea, Rumex scutatus) from which the epidermis was removed. In epidermis-free leaves no significant differences were found between adaxial and abaxial leaf sides, suggesting that leaf structure has negligible influence on the F(UV)/F(BG) ratios. On the other hand, fluorescence excitation ratios varied over a vast range when intact leaves from different species and habitats were investigated. Ratios were low in sun leaves and relatively high in shade- and greenhouse-grown leaves. By relating these results to those obtained with epidermis-free leaves, epidermal transmittances for UV-B radiation could be estimated, with values ranging between 1 and 45%. The data demonstrate a large adaptability of epidermal UV-A and UV-B transmittance in higher plants. The proposed method may prove a versatile and relatively simple tool for investigating epidermal UV transmittance complementing established methods. (author)

  3. Chlorophyll Fluorescence as a Tool to Assess the Regeneration Potential of African Violet Leaf Explants

    Directory of Open Access Journals (Sweden)

    Norbert KEUTGEN

    2016-06-01

    Full Text Available Micropropagation of many ornamentals has enabled their efficient commercialisation and many problems have been solved by the elaboration of adequate culture protocols. Nevertheless, a non-destructive technique for monitoring the developmental progress of explants would be desirable. The present study focussed on the applicability of chlorophyll fluorescence in leaf explants of African violet (a Saintpaulia ionantha × confusa – hybrid explanted onto Murashige and Skoog basic medium. The explants that survived on the medium without additional phytohormones had the capacity to develop further into two different kinds of explants: light green explants, characterized by a non-regular size growth and stiffer appearance, and dark green explants capable of organogenesis. Compared to the source leaves of African violet plants, explants were characterized by reduced chlorophyll (Chl and carotenoid (Car contents as well as a tendency towards a higher Car/Chl ratio. The Chl a/b ratio decreased significantly in the light green explants. A reduction of maximum quantum efficiency of photosystem II (Fv/Fm accompanied by a high percentage (> 50% of thermal energy dissipation as a consequence of an elevated light intensity (800 µmol m-2 s-1 quanta indicated photoinhibition in the light green explants, whereas in the dark green explants the largest percentage (> 50% of the light energy was dissipated into the fraction of photon energy trapped by ‘closed’ photosystem II reaction centres. These results suggest that the capacity of organogenesis of leaf explants of African violet can be monitored using chlorophyll fluorescence, because it is related to modifications of the photosynthetic system.

  4. Changes in Chlorophyll Fluorescence of Rice Mutants Induced by High Hydrostatic Pressure

    Institute of Scientific and Technical Information of China (English)

    BAI; Cheng-ke; LI; Gui-shuang; PENG; Chang-lian; DUAN; Jun

    2003-01-01

    Three mutants of rice (Oryza sativa L. ), Mutant 1, Mutant 2and Mutant 3, which were selected by high hydrostatic pressure (75 MPa), and their parent Yuexiangzhan were used to study the changes in chlorophyll fluorescence during different growth stages. In all the three mutants, the function of PSⅡ was improved, Fy/Fm ratio of mutants increased compared to their parent at tillering and heading stage, and φPS Ⅱ also improved except for Mutant 2 at heading stage. Similar to their parent, the mutants exhibited slight photoinhibition at noon and almost complete recovery to initial levels of 6:00 after 18:00 at heading stage. At milking stage, the photoinhibition in the mutants was obvious, and recovered rapidly compared to the parent. Yields of individual plant and grain/straw ratio were also higher in three mutants than the parent. Results indicated that characteristics of chlorophyll fluorescence in leaves of mutants and their photoinhibition in the field had changed. It is suggested that high hydrostatic pressure induction could be applied as a new effective approach in high-yield rice breeding in the future.

  5. Millimeter scale profiles of chlorophyll fluorescence: Deciphering the microscale spatial structure of phytoplankton

    Science.gov (United States)

    Doubell, Mark J.; Prairie, Jennifer C.; Yamazaki, Hidekatsu

    2014-03-01

    Marine food webs and biogeochemical cycles are driven by interactions between individual phytoplankton and other micro-organisms embedded within turbulent flows. Understanding the causes and ecological consequences of these interactions requires measurement of the spatial distribution of organisms across sub-meter scales relevant to their activities. However, estimates of many microscale processes (e.g., encounter rates, competition) are implicitly based on a random distribution of plankton despite increasing evidence of patchy distributions of turbulence and phytoplankton at the oceans microscale. Further complicating our understanding of microscale phytoplankton ecology, recent studies have suggested that the high levels of fluorescence variability measured at sub-centimeter scales may be due to the detection of separate, large phytoplankton particles (i.e. large cells, chains and aggregates) rather than 'patches' of increased cell abundances. By comparing coincident fluorescence estimates measured with millimeter (μL) and centimeter (mL) scale resolution, we show that estimates of phytoplankton biomass made at centimeter scales are consistent with averaging discrete variations in fluorescence measured at millimeter scales and that a critical scale exists where measures of fluorescence variability transitions from representing an individual to a patch. Application of nearest neighbor analysis to the discrete fluorescence patterns showed deviations from complete spatial randomness towards clustering across scales of millimeters to tens of centimeters. The strength of the deviation from random increased significantly in regions of elevated phytoplankton concentrations. No relationship was observed between fluorescent particle concentrations or nearest neighbor distances with the rate of dissipation of turbulent kinetic energy. Our results provide empirical evidence that the scale at which phytoplankton distributions are estimated by chlorophyll fluorescence may be

  6. Chlorophyll Fluorescence Emissions of Vegetation Canopies From High Resolution Field Reflectance Spectra

    Science.gov (United States)

    Middleton, E. M.; Corp, L. A.; Daughtry, C. S. T.; Campbell, P. K. Entcheva

    2006-01-01

    A two-year experiment was performed on corn (Zea mays L.) crops under nitrogen (N) fertilization regimes to examine the use of hyperspectral canopy reflectance information for estimating chlorophyll fluorescence (ChlF) and vegetation production. 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 ChlF peaks centered at 685V10 nm and 735V5 nm. Methods have been developed elsewhere to extract steady state solar induced fluorescence (SF) 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, as part of an ongoing multi-year experiment at the USDA/Agriculture Research Service in Beltsville, MD. A spectroradiometer (ASD-FR Fieldspec Pro, Analytical Spectral Devices, Inc., Boulder, CO) was used to measure canopy radiances 1 m above plant canopies with a 22deg field of view and a 0deg nadir view zenith angle. Canopy and plant measurements were made at the R3 grain fill reproductive stage on 3-4 replicate N application plots provided seasonal inputs of 280, 140, 70, and 28 kg N/ha. Leaf level measurements were also made which included ChlF, photosynthesis, and leaf constituents (photosynthetic pigment, carbon (C), and N contents). Crop yields were determined at harvest. SIF intensities for ChlF were derived directly from canopy reflectance spectra in specific narrowband regions associated with atmospheric oxygen absorption features centered at 688 and 760 nm. The red/far-red S F ratio derived from these field reflectance spectra successfully discriminated foliar pigment levels (e.g., total chlorophyll, Chl) associated with N application rates in both corn crops. This canopy-level spectral ratio was also

  7. Temporal variability in chlorophyll fluorescence of back-reef corals in Ofu, American Samoa

    Science.gov (United States)

    Piniak, G.A.; Brown, E.K.

    2009-01-01

    Change in the yield of chlorophyll a fluorescence is a common indicator of thermal stress in corals. The present study reports temporal variability in quantum yield measurements for 10 coral species in Ofu, American Samoa - a place known to experience elevated and variable seawater temperatures. In winter, the zooxanthellae generally had higher dark-adapted maximum quantum yield (F v/Fm), higher light- adapted effective quantum yield (??F/F'm), and lower relative electron transport rates (rETR) than in the summer. Temporal changes appeared unrelated to the expected bleaching sensitivity of corals. All species surveyed, with the exception of Montipora grisea, demonstrated significant temporal changes in the three fluorescence parameters. Fluorescence responses were influenced by the microhabitat - temporal differences in fluorescence parameters were usually observed in the habitat with a more variable temperature regime (pool 300), while differences in Fv/Fm between species were observed only in the more environmentally stable habitat (pool 400). Such species-specific responses and microhabitat variability should be considered when attempting to determine whether observed in situ changes are normal seasonal changes or early signs of bleaching. ?? 2009 Marine Biological Laboratory.

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

    OpenAIRE

    Elżbieta Kaczmarska; Władysław Michałek

    2014-01-01

    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 fluore...

  9. Changes in chlorophyll fluorescence and photosynthetic activity of French bean leaves induced by gamma radiation

    International Nuclear Information System (INIS)

    When exposed to gamma-radiation (12, 8 and 3.5 kGy), the growth of bean seedlings (Phaseolus vulgaris L.) was stopped and after some hours or days the plants began to wilt in a dose-dependent manner, starting from the leaf rim. The rate of the dark respiration (R) of leaves increased and that of net photosynthesis (P(N)) was strongly reduced. The regulation of stomata opening and closure was lost and the stomatal conductance (g(s)) of the gamma-ray exposed plants was strongly reduced. The reduced P(N) was only partly due to either the partial or almost full stomata closure. Chlorophyll (Chl) fluorescence measurements witha two-wavelength fluorometer and a PAM fluorometer showed an increasingly reduced variable fluorescence F(v), lower values of R(fd), of ground fluorescence F0, and of the fluorescence ratios F(v)/F(m) and F(v)/F(o). This indicated a damage to the photosynthetic apparatus. The increasing loss of photosynthetic pigments in the 350 krad exposed plants was also detected via an increase in the fluorescence ratio F690/F730. The performance of the light driven xanthophyll cycle (violaxanthin/zeaxanthin transformation) proceeded in the gamma-ray treated plants only at reduced rates. The gamma-ray damage of plants can best be detected by measurements of stomatal conductance, P(N) and various Chl fluorescence ratios such as R(fd), F(v)/F(o) and F(v)/F(m)

  10. 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.

  11. [Flag leaf photosynthetic characteristics, change in chlorophyll fluorescence parameters, and their relationships with yield of winter wheat sowed in spring].

    Science.gov (United States)

    Xu, Lan; Gao, Zhi-qang; An, Wei; Li, Yan-liang; Jiao, Xiong-fei; Wang, Chuang-yun

    2016-01-01

    With five good winter wheat cultivars selected from the middle and lower reaches of Yangtze River and Southwest China as test materials, a field experiment in Xinding basin area of Shanxi Province was conducted to study the photosynthetic characteristics, chlorophyll content, and chlorophyll fluorescence parameters of flag leaf at different sowing dates, as well as the correlations between these indices and yield for two years (2013-2014). The results showed that the difference in most fluorescence parameters except chlorophyll content among cultivars was significant. The correlations between these fluorescence parameters and yield were significant. The variation coefficient of chlorophyll (Chl) content was low (0.12-0.17), and that of performance index based on absorption (PIabs) was high (0.32-0.39), with the partial correlation coefficients of them with grain yield from 2013 to 2014 ranged in 0.70-0.81. Under the early sowing condition, the grain yield positively correlated with PIabs at flowering and filling stages and chlorophyll content at grain filling stage, but negatively correlated with the relative variable fluorescence at I point (Vi) at grain filling stage. About 81.1%-82.8% of grain yield were determined by the variations of PIabs, Chl, and Vi. Wheat cultivars had various performances in the treatments with different sowing dates and a consistent trend was observed in the two experimental years. Among these 5 cultivars, Yangmai 13 was suitable for early sowing, with the flag leaf photosynthetic rate (Pn), Chl, most fluorescence parame-ters, and grain yield showed obviously high levels. In conclusion, under early sowing condition chlorophyll content at grain filling stages, PIabs at flowering and filling stages, and Pn were important indices for selecting wheat cultivars with high photosynthetic efficiency. PMID:27228602

  12. 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

  13. High-light stress and photoprotection in Umbilicaria antarctica monitored by chlorophyll fluorescence imaging and changes in zeaxanthin and glutathione.

    Science.gov (United States)

    Barták, M; Hájek, J; Vráblíková, H; Dubová, J

    2004-05-01

    The effect of high light on spatial distribution of chlorophyll (Chl) fluorescence parameters over a lichen thallus (Umbilicaria antarctica) was investigated by imaging of Chl fluorescence parameters before and after exposure to high light (1500 micro mol m (-2) s (-1), 30 min at 5 degrees C). False colour images of F (V)/F (M) and Phi (II) distribution, taken over thallus with 0.1 mm (2) resolution, showed that maximum F (V)/F (M) and Phi (II) values were located close to the thallus centre. Minimum values were typical for thallus margins. After exposure to high light, a differential response of F (V)/F (M) and Phi (II) was found. The marginal thallus part exhibited a loss of photosynthetic activity, manifested as a lack of Chl fluorescence signal, and close-to-centre parts showed a different extent of F (V)/F (M) and Phi (II) decrease. Subsequent recovery in the dark led to a gradual return of F (V)/F (M) and Phi (II) to their initial values. Fast (30 min) and slow (1 - 22 h) phase of recovery were distinguished, suggesting a sufficient capacity of photoprotective mechanisms in U. antarctica to cope with low-temperature photoinhibition. Glutathione and xanthophyll cycle pigments were analyzed by HPLC. High light led to an increase in oxidized glutathione (GSSG), and a conversion of violaxanthin to zeaxanthin, expressed as their de-epoxidation state (DEPS). The responses of GSSG and DEPS were reversible during subsequent recovery in the dark. GSSG and DEPS were highly correlated to non-photochemical quenching (NPQ), indicating involvement of these antioxidants in the resistance of U. antarctica to high-light stress. Heterogeneity of Chl fluorescence parameters over the thallus and differential response to high light are discussed in relation to thallus anatomy and intrathalline distribution of the symbiotic alga Trebouxia sp. PMID:15143442

  14. Geomagnetic and strong static magnetic field effects on growth and chlorophyll a fluorescence in Lemna minor.

    Science.gov (United States)

    Jan, Luka; Fefer, Dušan; Košmelj, Katarina; Gaberščik, Alenka; Jerman, Igor

    2015-04-01

    The geomagnetic field (GMF) varies over Earth's surface and changes over time, but it is generally not considered as a factor that could influence plant growth. The effects of reduced and enhanced GMFs and a strong static magnetic field on growth and chlorophyll a (Chl a) fluorescence of Lemna minor plants were investigated under controlled conditions. A standard 7 day test was conducted in extreme geomagnetic environments of 4 µT and 100 µT as well as in a strong static magnetic field environment of 150 mT. Specific growth rates as well as slow and fast Chl a fluorescence kinetics were measured after 7 days incubation. The results, compared to those of controls, showed that the reduced GMF significantly stimulated growth rate of the total frond area in the magnetically treated plants. However, the enhanced GMF pointed towards inhibition of growth rate in exposed plants in comparison to control, but the difference was not statistically significant. This trend was not observed in the case of treatments with strong static magnetic fields. Our measurements suggest that the efficiency of photosystem II is not affected by variations in GMF. In contrast, the strong static magnetic field seems to have the potential to increase initial Chl a fluorescence and energy dissipation in Lemna minor plants. PMID:25708622

  15. Examination of chlorophyll fluorescence decay kinetics in sulfur deprived algae Chlamydomonas reinhardtii.

    Science.gov (United States)

    Volgusheva, A A; Zagidullin, V E; Antal, T K; Korvatovsky, B N; Krendeleva, T E; Paschenko, V Z; Rubin, A B

    2007-06-01

    Chlorophyll fluorescence decay kinetics was measured in sulfur deprived cells of green alga Chlamydomonas reinhardtii with a home made picosecond fluorescence laser spectrometer. The measurements were carried out on samples either shortly adapted to the dark ('Fo conditions') or treated to reduce Qa ('Fm conditions'). Bi-exponential fitting of decay kinetics was applied to distinguish two components one of them related to energy trapping (fast component) and the other to charge stabilization and recombination in PS 2 reaction centers (slow component). It was found that the slow component yield increased by 2.0 and 1.2 times when measured under 'Fo' and 'Fm conditions', respectively, in sulfur deprived cells as compared to control ones. An additional rapid rise of the slow component yield was observed when incubation was carried out in a sealed bioreactor and cell culture turned to anaerobic conditions. The obtained results strongly indicate the existence of the redox control of PS 2 activity during multiphase adaptation of C. reinhardtii to sulfur deficiency stress. Probable mechanisms responsible for the observed increased recombinant fluorescence yield in starved cells are discussed. PMID:17543273

  16. [Remote sensing of chlorophyll fluorescence at airborne level based on unmanned airship platform and hyperspectral sensor].

    Science.gov (United States)

    Yang, Pei-Qi; Liu, Zhi-Gang; Ni, Zhuo-Ya; Wang, Ran; Wang, Qing-Shan

    2013-11-01

    The solar-induced chlorophyll fluorescence (ChlF) has a close relationship with photosynthetic and is considered as a probe of plant photosynthetic activity. In this study, an airborne fluorescence detecting system was constructed by using a hyperspectral imager on board an unmanned airship. Both Fraunhofer Line Discriminator (FLD) and 3FLD used to extract ChlF require the incident solar irradiance, which is always difficult to receive at airborne level. Alternative FLD (aFLD) can overcome the problem by selecting non-fluorescent emitter in the image. However, aFLD is based on the assumption that reflectance is identical around the Fraunhofer line, which is not realistic. A new method, a3FLD, is proposed, which assumes that reflectance varies linearly with the wavelength around Fraunhofer line. The result of simulated data shows that ChlF retrieval error of a3FLD is significantly lower than that of aFLD when vegetation reflectance varies near the Fraunhofer line. The results of hyperspectral remote sensing data with the airborne fluorescence detecting system show that the relative values of retrieved ChlF of 5 kinds of plants extracted by both aFLD and a3FLD are consistent with vegetation growth stage and the ground-level ChlF. The ChlF values of aFLD are about 15% greater than a3FLD. In addition, using aFLD, some non-fluorescent objects have considerable ChlF value, while a3FLD can effectively overcome the problem. PMID:24555390

  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...... 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 of...

  18. Effects of space environment on chlorophyll fluorescence and photosynthesis characteristics of wheat

    International Nuclear Information System (INIS)

    The effects of the space environment on the chlorophyll fluorescence parameters and photosynthesis characteristics of wheat cultivars, Xinong 1043 M1 and Shaan253 M1, were studied. The results showed that the decrement of contents of PS II primary photochemical efficiency (Fv/Fm), potential activity (Fv/F0), photochemical quenching coefficient (qP) and photosynthesis rate (Pn) were less than that of control, increment of non-photochemical quenching coefficient (qN) were more than that of control. The results suggested that photosynthetic apparatus were damaged, photosynthetic electron transport, photosynthetic primary reaction were inhibited, rate of photosynthesis decreased and growth of M1 plant were retarded, which leading to thousand kernel weights decreased. (authors)

  19. 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.

  20. 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.

  1. Temperature and light tolerance of representative brown,green and red algae in tumble culture revealed by chlorophyll fluorescence measurements

    Institute of Scientific and Technical Information of China (English)

    PANG Shaojun; SHAN Tifeng

    2008-01-01

    Laminaria japonica,Undaria pinnatifida,Ulva lactuca,Grateloupia turuturu and Palmaria palmata are suitable species that fit the requirements of a seaweed-animal integrated aquaculture system in terms of their viable biomass,rapid growth and promising nutrient uptake rates. In this investigation,the responses of the optimal chlorophyll fluolescence yield of the five algal species in tumble culture were assessed at a temperature range of 10~30℃.The results revealed that Ulva lactuca was the most resistant species to high temperature,withstanding 30℃ for 4 h without apparent decline in the optimal chlorophyll fluorescence yield. While the arctic alga Palmaria palmata was the most vulnerable one,showing significant decline in the optimal chlorophyll fluorescence yield at 25℃ for 2 h.The cold-water species Laminaria japonica,however,demonstrated strong ability to cope with higher temperature(24~26℃)for shorter time(within 24 h)without significant decline in the optimal chlorophyll fluorescence yield.Grateloupia turuturu showed a general decrease in the optimal chiorophyll fluores-cence yield with the rising temperature from 23 to 30℃,similar to the temperate kelp Undaria pinnatifida.Changes of chio-rophyll fluorescence yields of these algae were characterized differently indicating the existence of species-unique strategy to cope with high light.Measurements of the optimal chlorophyll fluorescence yield after short exposure to direct solar irradiance revealed how long these exposures could be without significant photoinhibition or with promising recovery in photosynthetic activities. Seasonal pattern of alternation of algal species in tank culture in the Northern Hemisphere at the latitude of 36°Nwas proposed according to these basic measurements.

  2. [Effects of controlled-release fertilizer on chrysanthemum leaf chlorophyll fluorescence characteristics and ornamental quality].

    Science.gov (United States)

    Song, Xu-xu; Zheng, Cheng-shu; Sun, Xia; Ma, Hai-yan

    2011-07-01

    Taking cut flower chrysanthemum 'Baima' as test material, a pot experiment was conducted to study the effects of controlled-release fertilizer on the leaf chlorophyll fluorescence parameters, chlorophyll and nutrient contents, and ornamental quality of chrysanthemum. Under no fertilization, the maximal photochemical efficiency of PS II in dark (F(v)/F(m)), potential photochemical efficiency of PS II (F(v)/F(0)), and quantum yield of PS II electron transport (phi(PS II)) decreased significantly, compared with those under fertilization. With the application of conventional compound fertilizers CCFA (N:P:K=20:8:10) and CCFB (N:P:K= 14:14:14), the F(v)/F(m), F(v)/F(0) and phi(PS II) had a slight increase in early period (30-60 d) but a remarkable decrease in mid and later periods (75 - 120 d), compared with those under the application of controlled-release fertilizers CRFA (N:P:K = 20:8:10) and CRFB (N:P:K= 14:14:14). Under the application of CRFA, the F(v)/F(m), phi(PS II), and photochemical quenching (q(P)) had somewhat increase, as compared with the application of CRFB. The non-photochemical quenching (NPQ) under the application of CRFA and CRFB decreased significantly, compared with that under the application of CCFA and CCFB and the control. The chlorophyll content had a similar change trend with F(v)/F(m), F(v)/F(0), and phi(PS II). The leaf N, P, and K contents, flower stalk length and stalk diameter, flower diameter, and flower fresh and dry mass at harvest stage all increased under the application of CRFA and CRFB, compared with those under the application of CCFA and CCFB and the control, and the flower fresh and dry mass was significantly higher under the application of CRFA than of CRFB. This study showed that controlled-release fertilizer could improve the ornamental quality of chrysanthemum via improving the leaf chlorophyll content, photochemical transduction rate, and nutrient uptake, and CRFA had better effects than CRFB. PMID:22007449

  3. The photosynthesis of individual algal cells during the cell cycle of Scenedesmus quadricauda studied by chlorophyll fluorescence kinetic microscopy

    Czech Academy of Sciences Publication Activity Database

    Šetlíková, Eva; Šetlík, Ivan; Kupper, H.; Kasalický, Vojtěch; Prášil, Ondřej

    2005-01-01

    Roč. 84, - (2005), s. 113-120. ISSN 0166-8595 R&D Projects: GA MŠk LN00A141; GA MŠk 1P05ME824 Grant ostatní: NATO EST CLG 981009 Institutional research plan: CEZ:AV0Z5020903 Keywords : cell cycle * chlorophyll fluorescence kinetics * fluorescence microscopy Subject RIV: EE - Microbiology, Virology Impact factor: 2.295, year: 2005

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

    OpenAIRE

    Kang Yu; Georg Leufen; Mauricio Hunsche; Georg Noga; Xinping Chen; Georg Bareth

    2013-01-01

    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...

  5. Chlorophyll fluorescence remote sensing from space in scattering atmospheres: implications for its retrieval and interferences with atmospheric CO2 retrievals

    OpenAIRE

    J. McDuffie; L. Guanter; C. O'Dell; C. Frankenberg

    2012-01-01

    With the advent of dedicated greenhouse-gas space-borne spectrometers sporting high resolution spectra in the O2 A-band spectral region (755–774 nm), the retrieval of chlorophyll fluorescence has become feasible on a global scale. If unaccounted for, however, fluorescence can indirectly perturb the greenhouse gas retrievals as it perturbs the oxygen absorption features. As atmospheric CO2 measurements are used to invert net fluxes at the land-atmosphere interface, a bias caused by fluore...

  6. Method 445.0 In Vitro Determination of Chlorophyll a and Pheophytin ain Marine and Freshwater Algae by Fluorescence

    Science.gov (United States)

    This method provides a procedure for low level determination of chlorophyll a (chl a) and its magnesium free derivative, pheophytin a (pheo a), in marine and freshwater phytoplankton using fluorescence detection.(1,2) Phaeophorbides present in the sample are determined collective...

  7. The effect of UV-B radiation on the chlorophyll fluorescence parameters of the husked and the naked oat

    OpenAIRE

    Elżbieta Skórska

    2013-01-01

    Naked oat variety of STH296 showed higher tolerance than traditional variety Bajka on short-term UV-B radiation (UV-BBE=1 1 kJ·m-2) on the stage of primary photosynthesis reaction recorded using chlorophyll fluorescence induction of the leaves.

  8. Modeling of Chlorophyll a fluorescence kinetics in plnat cells: Derřivation of a descriptive algorithm

    Czech Academy of Sciences Publication Activity Database

    Vredenberg, W.; Prášil, Ondřej

    Dordrecht: Springer, 2009 - (Laisk, A.; Nedbal, L.; Govindjee), s. 125-149 ISBN 978-1-4020-9236-7 R&D Projects: GA ČR GA206/05/0335; GA AV ČR 1QS500200570 Institutional research plan: CEZ:AV0Z50200510 Keywords : Chlorophyll a * variable fluorescence * photosystem II Subject RIV: EE - Microbiology, Virology

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

    Czech Academy of Sciences Publication Activity Database

    Vredenberg, W.; Prášil, Ondřej

    2013-01-01

    Roč. 117, 1-3 (2013), s. 321-337. ISSN 0166-8595 R&D Projects: GA MŠk(CZ) ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : Chlorophyll a fluorescence * Photosystem II * Quenching kinetics Subject RIV: EE - Microbiology, Virology Impact factor: 3.185, year: 2013

  10. Effect of four levels of shade on survival, morphology and chlorophyll fluorescence of Nothofagus alessandrii container-grown seedlings

    Directory of Open Access Journals (Sweden)

    Santelices R

    2015-10-01

    Full Text Available Nothofagus alessandrii (ruil is a threatened, endemic tree of the Mediterranean zone of Chile. As a result of past anthropogenic activities, its current cover has been reduced to only 314 hectares across several fragmented and degraded areas. Although activities to conserve and recover such forests have been developed, little is known about their propagation and nursery cultivation, since the plant’s quality is one of the most important factors for restoration and reforestation plans, re-vegetation, or forest enrichment. The success of restoration programs in these areas will require improvements in plant production, being important to test the shade effects on seedling survival and growth. This paper reports the results of testing for survival, morphological and chlorophyll fluorescence differences in N. alessandrii seedlings grown for approximately 32 weeks in unshaded conditions and under three different levels of shading (18%, 50%, and 80% shade. Morphological traits (stem height, root collar diameter, specific leaf area, shoot and root biomass, and quality indexes and survival were measured. Chlorophyll fluorescence was also measured to analyze the shade tolerance of the species. Analysis showed significant differences for most traits as a consequence of the shade level. Seedlings exposed to 18% shade showed the highest total dry biomass, while those exposed to 80% shade showed the highest survival rate (92%. Chlorophyll fluorescence was high in the unshaded conditions and medium in the 18-50% shade. Morphological and chlorophyll fluorescence responses differed greatly among shade levels and corresponded with the degree of shade tolerance of the species.

  11. Using violet laser-induced chlorophyll fluorescence emission spectra for crop yield assessment of cowpea (Vigna unguiculata (L) Walp) varieties

    Science.gov (United States)

    Anderson, Benjamin; Buah-Bassuah, Paul K.; Tetteh, Jonathan P.

    2004-07-01

    The use of violet laser-induced chlorophyll fluorescence (LICF) emission spectra to monitor the growth of five varieties of cowpea in the University of Cape Coast Botanical Garden is presented. Radiation from a continuous-wave violet laser diode emitting at 396 nm through a fibre is closely incident on in vivo leaves of cowpea to excite chlorophyll fluorescence, which is detected by an integrated spectrometer with CCD readout. The chlorophyll fluorescence spectra with peaks at 683 and 731 nm were used for growth monitoring of the cowpea plants over three weeks and analysed using Gaussian spectral functions with curve fitted parameters to determine the peak positions, area under the spectral curve and the intensity ratio F683/F731. The variation in the intensity ratio of the chlorophyll bands showed sensitive changes indicating the photosynthetic activity of the cowpea varieties. A discussion of the fluorescence result as compared to conventional assessment is presented with regard to discrimination between the cowpea varieties in terms of crop yield performance.

  12. Near-distance imaging spectroscopy investigating chlorophyll fluorescence and photosynthetic activity of grassland in the daily course

    Czech Academy of Sciences Publication Activity Database

    Ač, Alexander; Marek, Michal V.; Malenovský, Z.; Hanuš, Jan; Urban, Otmar; Tomášková, Ivana

    -, - (2009), od 1006 do 1015. ISSN 1445-4408 R&D Projects: GA MŠk 2B06068 Institutional research plan: CEZ:AV0Z60870520 Keywords : imaging spectroscopy * chlorophyll fluorescence * grassland Subject RIV: ED - Physiology Impact factor: 1.678, year: 2009

  13. 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.

  14. The effect of UV-B and UV-C radiation on Hibiscus leaves determined by ultraweak luminescence and fluorescence induction [chlorophyll fluorescence induction, ultraweak luminescence

    International Nuclear Information System (INIS)

    The effects of UV-C (254 nm) and UV-B (280-320 nm) on chlorophyll fluorescence induction and ultraweak luminescence (UL) in detached leaves of Hibiscus rosa-sinensis L. were investigated. UL from leaves exposed to UV-B and UV-C radiation reached a maximum 72 h after irradiation. In both cases most of the light was of a wavelength over 600 nm. An increase in the percentage of long wavelength light with time was detected. UV radiation increased peroxidase activity, which also reached a maximum 72 h after irradiation. UV-B and UV-C both reduced variable chlorophyll fluorescence. No effect on the amount of chlorophyll or UV screening pigments was observed with the short-term irradiation used in this investigation. (author)

  15. Alterations in Chlorophyll a Fluorescence and Pigments Concentration in the Leaves of Cauliflower and Broccoli Transplants Subjected to Chilling

    Directory of Open Access Journals (Sweden)

    Renata WOJCIECHOWSKA

    2016-06-01

    Full Text Available Chlorophyll a fluorescence parameters and photosynthetic pigments content in leaves of broccoli (Brassica oleracea L. var. italica cv. ‘Monaco’ F1 and cauliflower (Brassica oleracea L. var. botrytis cv. ‘Bruce’ F1 transplants were analyzed to investigate the effects of chilling temperatures (6 and 10 °C and the exposure length (1 or 2 weeks on the photosynthetic apparatus condition in 3-year experiment. Data were compared to control plants exposed to 14 °C for 1 and 2 weeks. The lowest values of maximum quantum efficiency of photosystem II (Fv/Fm and the performance index (PI were observed in cauliflower chilled at 6 °C for 2 weeks. This was not accompanied by any substantial reduction in chlorophylls concentration, however, significant correlations between Fv/Fm or PI and chlorophylls content in cauliflower leaves were found. There was no negative effects of chilling on photosynthetic activity and chlorophyll content in broccoli leaves, the amount of carotenoids significantly increased in the broccoli chilled for 2 weeks in 6 °C. The chlorophyll a fluorescence indices and accelerated carotenoids synthesis showed that broccoli had less vulnerable photosynthetic apparatus to stress-induced temperatures and more efficient protection mechanisms in comparison to cauliflower transplants.

  16. Effect of Methanol on Photosynthesis and Chlorophyll Fluorescence of Flag Leaves of Winter Wheat

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yue-jin; YANG Yue-qin; LIANG Shan-shan; YI Xian-feng

    2008-01-01

    Photosynthesis and chlorophyll a fluorescence parameters, photochemical efficiency of PS II (Fv/Fm), photochemical quenching of PS II (qP), nonphotochemical quenching of PS II (NPQ), maximum activity of PS II (Fv/Fo) as well as electron transport rate (ETR), and quantum yield of PS II (ΦPS II) were measured on flag leaves of the winter wheat treated by methanol at different concentrations. The results revealed that photosynthesis was greatly improved by methanol, as indicated by higher photosynthetic rates and stomatal conductance. The enhancement effect of methanol on photosynthesis was maintained for 3-4 days. Different methanol concentration treatments also increased intercellular CO2 concentration and transpiration rates. No significant decline was found in Fv/Fm, Fv/Fo, and ΦPS II, which revealed no photoinhibition during methanol application in different methanol concentrations. Methanol showing no apparent inhibitory effects indicated higher potential photosynthetic capacity of flag leaves of winter wheat. However, the increase in photosynthesis was not followed by an increase in the photosynthetic activity (Fv/Fm), and fluorescence parameters did not indicate an improvement in intercellular CO2 concentration and PS II photochemical efficiency compared with the control, thereby encouraging us to propose that lower leaf temperatures caused by applied methanol would reduce both dark respiration and photorespiration (most importantly), thus, increasing net CO2 uptake and photosynthetic rates.

  17. Diffuse reflectance of the ocean - The theory of its augmentation by chlorophyll a fluorescence at 685 nm

    Science.gov (United States)

    Gordon, H. R.

    1979-01-01

    The radiative transfer equation is modified to include the effect of fluorescent substances and solved in the quasi-single scattering approximation for a homogeneous ocean containing fluorescent particles with wavelength independent quantum efficiency and a Gaussian shaped emission line. The results are applied to the in vivo fluorescence of chlorophyll a (in phytoplankton) in the ocean to determine if the observed quantum efficiencies are large enough to explain the enhancement of the ocean's diffuse reflectance near 685 nm in chlorophyll rich waters without resorting to anomalous dispersion. The computations indicate that the required efficiencies are sufficiently low to account completely for the enhanced reflectance. The validity of the theory is further demonstrated by deriving values for the upwelling irradiance attenuation coefficient at 685 nm which are in close agreement with the observations.

  18. Potential of chlorophyll fluorescence imaging for assessing bio-viability changes of biodeteriogen growths on stone monuments

    Science.gov (United States)

    Osticioli, I.; Mascalchi, M.; Pinna, D.; Siano, S.

    2013-05-01

    A systematic study on the use of Chlorophyll Fluorescence (CF) imaging in Pulsed Amplitude Modulated (PAM) for assessing viability changes of biodeteriogen on stone artifacts has been carried out. The experimentation has been performed on different phototrophic organisms of gravestone slabs from the monumental British Cemetery of Florence (Italy). Since the viability of these organisms and then their chlorophyll fluorescence emission is strongly dependent on the environmental conditions, a preliminary study on the effects of local patterns during the season was carried out. The trend of the fluorescence quantum yield (QYmax) at different dark adapted times in different periods of the year was determined. The results achieved in our work proves the effectiveness of the CF-PAM imaging for in situ lichen characterizations in conservation studies and defines an optimized application protocol.

  19. 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

  20. Assessing boreal forest photosynthetic dynamics through space-borne measurements of greenness, chlorophyll fluorescence and model GPP

    Science.gov (United States)

    Walther, Sophia; Guanter, Luis; Voigt, Maximilian; Köhler, Philipp; Jung, Martin; Joiner, Joanna

    2015-04-01

    sophia.walther@gfz-potsdam.de The seasonality of photosynthesis of boreal forests is an essential driver of the terrestrial carbon, water and energy cycles. However, current carbon cycle model results only poorly represent interannual variability and predict very different magnitudes and timings of carbon fluxes between the atmosphere and the land surface (e.g. Jung et al. 2011, Richardson et al. 2012). Reflectance-based satellite measurements, which give an indication of the amount of green biomass on the Earth's surface, have so far been used as input to global carbon cycle simulations, but they have limitations as they are not directly linked to instantaneous photosynthesis. As an alternative, space-borne retrievals of sun-induced chlorophyll fluorescence (SIF) boast the potential to provide a direct indication of the seasonality of boreal forest photosynthetic activity and thus to improve carbon model performances. SIF is a small electromagnetic signal that is re-emitted from the photosystems in the chloroplasts, which results in a direct relationship to photosynthetic efficiency. In this contribution we examine the seasonality of the boreal forests with three different vegetation parameters, namely greenness, SIF and model simulations of gross primary production (gross carbon flux into the plants by photosynthesis, GPP). We use the enhanced vegetation index (EVI) to represent green biomass. EVI is calculated from NBAR MODIS reflectance measurements (0.05deg, 16 days temporal resolution) for the time from January 2007-May 2013. SIF data originate from GOME-2 measurements on board the MetOp-A satellite in a spatial resolution of 0.5deg for the time from 2007-2011 (Joiner et al. (2013), Köhler et al. (2014)). As a third data source, data-driven GPP model results are used for the time from 2006-2012 with 0.5deg spatial resolution. The method to quantify phenology developed by Gonsamo et al. (2013) is applied to infer the main phenological phases (greenup/onset of

  1. Comparison of green and variegated foliage plant species based on chlorophyll fluorescence parameters under different light intensities

    International Nuclear Information System (INIS)

    To compare green and variegated foliage plants namely; Hedera helix, Ardisia pusilla and Scindapsus aureus were treated under three different light intensities (2, 10 and 20 micro mol-m-2-s-1) using florescent lights for three months, and photosynthetic characteristics and chlorophyll content were measured. IMAGING-PAM chlorophyll fluorescence system was used to determine photosynthetic characteristics. The results showed that Fv/Fm (maximal PS-II quantum yield) and Y (II) (effective PS-II quantum yield) values were lower in variegated species compared to those in green species at 2 micro mol-m-2-s-1 light intensity. Although, Fv/Fm and Y (II) values in variegated S. aureus was lower than variegated H. helix, but variegated S. aureus survived and Hedera helix plants died after low light treatment. In contrast, Fv/Fm and Y (II) values were increased in green and variegated species with increasing the light intensity, except Fv/Fm value for variegated S. aureus which was slightly decreased at 20 micro mol-m-2-s-1 light intensity. The ETR (electron transport rate) value was also lower in both green and variegated species at 2 micro mol-m-2-s-1 intensity. ETR values saturated in green and variegated plants with increasing the light intensity. Higher level of chlorophyll was obtained in green species compared to variegated species for both low and high light intensity treatments. Chlorophyll content in green species decreased at 20 micro mol-m-2-s-1 light intensity, whereas in variegated species, chlorophyll content increased with increasing the light intensities. The results of chlorophyll fluorescence parameters showed that especially low light intensity created stress condition in variegated foliage plants compared to green plants, and affected the normal growth and development. (author)

  2. Influence of foliar application of silicon on chlorophyll fluorescence, photosynthetic pigments, and growth in water-stressed wheat cultivars differing in drought tolerance

    OpenAIRE

    MAGHSOUDI, KOBRA; Emam, Yahya; Ashraf, Muhammad

    2015-01-01

    The influence of foliar application of silicon (Si) on chlorophyll contents, chlorophyll fluorescence, and growth of four wheat cultivars differing in drought tolerance (Sirvan and Chamran, as relatively drought tolerant, and Shiraz and Marvdasht, as drought sensitive) was examined under water deficit (100% and 40% F.C.) created in a greenhouse. The results showed that water deficit decreased shoot and root lengths, shoot dry weight, root dry weight, water utilization efficiency, chlorophyll ...

  3. 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.

  4. Effect of seabuckthorn extract on delayed chlorophyll fluorescence on Cd and Co ions treated wheat seedlings.

    Science.gov (United States)

    Ganiyeva, R A; Novruzov, E M; Bayramova, S A; Kurbanova, I M; Hasanov, R A

    2009-11-01

    The protecting effect of "Hypporamine PL" compound isolated from dry leaves of seabuckthorn (Hippophae rhamneides L.) on photosystem 2 (PS2) activity suppression induced by CdCl2 and CoCl2 treatment in the 7-day-old wheat seedlings (Triticum aestivum L.) under different pH of growth medium was investigated by measurement of millisecond delayed fluorescence (ms-DF) of chlorophyll intact leaves. The value o-i/p-s of ms-DF ratio was reduced under the Cd2+ and Co2+ treatments on 60 and 65% respectively at pH 6.7. Acidification of medium (pH 5.0) results in decreasing of ratio o-i/p-s only approximately on 30% in average. In the alkaline medium the lowering of o-i/p-s on 41% is observed in both ions treatments. This decreasing of o-i/p-s ratio occurred due to decreasing of fast phase o-i amplitude. At the same time the widening and increasing of slow phase p-s amplitude was observed. The compound "Hypporamine PL" limited the decrease of ms-DF components induced by heavy metals. It is suggested that the protective effect of "Hypporamine PL" on the photochemical reactions in the PS2 is due to catechins, epicatechins, quercetin and other polyphenols, containing in this compound, preventing the free radicals formation in the PS2 under treatment by heavy metal ions. PMID:20329404

  5. 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; Moran, M. Susan; Ponce-Campos, Guillermo; Beer, Christian; Camps-Valls, Gustavo; Buchmann, Nina; Gianelle, Damiano; Klumpp, Katja; Cescatti, Alessandro; Baker, John M.; Griffis, Timothy J.

    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.

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

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Andersen, Svend Bode; Ottosen, Carl-Otto; Rosenqvist, Eva

    2012-01-01

    Abstract. In view of the global climate change, heat stress is an increasing constraint for the productivity of wheat (Triticum aestivum L.). Our aim was to identify contrasting cultivars in terms of heat tolerance by mass screening of 1274 wheat cultivars of diverse origin, based on a...... a milder heat stress of 38Cin 300 mmolm–2 s–1 for 2 h with preheating at 33–35Cfor 19 h in 7–14 mmolm–2 s–1 light showed a genetic determination of 8.52.7%.Aheat treatment of 40Cin 300 mmolm–2 s–1 for 72 h in the second screening with 138 selected cultivars resulted in larger differentiation of...... cultivars 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...

  7. Global Monitoring of Terrestrial Chlorophyll Fluorescence from Moderate-spectral-resolution Near-infrared Satellite Measurements: Methodology, Simulations, and Application to GOME-2

    Science.gov (United States)

    Joiner, J.; Gaunter, L.; Lindstrot, R.; Voigt, M.; Vasilkov, A. P.; Middleton, E. M.; Huemmrich, K. F.; Yoshida, Y.; Frankenberg, C.

    2013-01-01

    Globally mapped terrestrial chlorophyll fluorescence retrievals are of high interest because they can provide information on the functional status of vegetation including light-use efficiency and global primary productivity that can be used for global carbon cycle modeling and agricultural applications. Previous satellite retrievals of fluorescence have relied solely upon the filling-in of solar Fraunhofer lines that are not significantly affected by atmospheric absorption. Although these measurements provide near-global coverage on a monthly basis, they suffer from relatively low precision and sparse spatial sampling. Here, we describe a new methodology to retrieve global far-red fluorescence information; we use hyperspectral data with a simplified radiative transfer model to disentangle the spectral signatures of three basic components: atmospheric absorption, surface reflectance, and fluorescence radiance. An empirically based principal component analysis approach is employed, primarily using cloudy data over ocean, to model and solve for the atmospheric absorption. Through detailed simulations, we demonstrate the feasibility of the approach and show that moderate-spectral-resolution measurements with a relatively high signal-to-noise ratio can be used to retrieve far-red fluorescence information with good precision and accuracy. The method is then applied to data from the Global Ozone Monitoring Instrument 2 (GOME-2). The GOME-2 fluorescence retrievals display similar spatial structure as compared with those from a simpler technique applied to the Greenhouse gases Observing SATellite (GOSAT). GOME-2 enables global mapping of far-red fluorescence with higher precision over smaller spatial and temporal scales than is possible with GOSAT. Near-global coverage is provided within a few days. We are able to show clearly for the first time physically plausible variations in fluorescence over the course of a single month at a spatial resolution of 0.5 deg × 0.5 deg

  8. Effects of nitrogen form on growth, CO2 assimilation, chlorophyll fluorescence, and photosynthetic electron allocation in cucumber and rice plants*

    OpenAIRE

    Zhou, Yan-Hong; Zhang, Yi-li; Wang, Xue-Min; Cui, Jin-xia; Xia, Xiao-Jian; Kai SHI; Yu, Jing-quan

    2011-01-01

    Cucumber and rice plants with varying ammonium (NH4 +) sensitivities were used to examine the effects of different nitrogen (N) sources on gas exchange, chlorophyll (Chl) fluorescence quenching, and photosynthetic electron allocation. Compared to nitrate (NO3 −)-grown plants, cucumber plants grown under NH4 +-nutrition showed decreased plant growth, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide (CO2) level, transpiration rate, maximum phot...

  9. Gas Exchange, Chlorophyll Fluorescence and Antioxidants as Bioindicators of Airborne Heavy Metal Pollution in Jeddah, Saudi Arabia

    OpenAIRE

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

    2013-01-01

    Lettuce (Lactuca sativa L. cv. Romaine) plants were exposed to different levels of urbanization in Jeddah city, Saudi Arabia. They showed different degrees of visible injury symptoms and dramatic changes in enzymatic activities as well as net photosynthetic rates (PN), variable to maximum chlorophyll fluorescence (Fv/Fm) and stomatal conductance (gs).Visual symptoms of phytotoxicity of heavy metals were observed on plants grown at industrial and urban areas, where the concentrations of metals...

  10. Spatial location of photosystem pigment-protein complexes in thylakoid membranes of chloroplasts of Pisum sativum studied by chlorophyll fluorescence

    International Nuclear Information System (INIS)

    Ultrastructure of plant chloroplasts was studied by a single-molecule spectroscopy setup at a temperature of 77 K exploring spatial location of photosystems. Two chloroplast thylakoid membrane regions were visualized by fluorescence microscopy and detected at different wavelengths. The size of these regions and the spatial resolution of the microscope allowed us to measure their chlorophyll fluorescence emission spectra of these membrane domains. While the grana regions are characterized by a predominant presence of Photosystem II pigment-protein complexes emitting at 685 nm, Photosystem I complexes are localized in stroma regions and emit at 730 nm

  11. Spatial location of photosystem pigment-protein complexes in thylakoid membranes of chloroplasts of Pisum sativum studied by chlorophyll fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Vacha, F. [Institute of Physical Biology, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic) and Biological centre, Academy of Sciences of the Czech Republic, UMBR, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic)]. E-mail: vacha@jcu.cz; Adamec, F. [Institute of Physical Biology, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Biological centre, Academy of Sciences of the Czech Republic, UMBR, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Valenta, J. [Institute of Physical Biology, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2 (Czech Republic); Vacha, M. [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1-S8, Meguro-ku, Tokyo, 152-8552 (Japan)

    2007-01-15

    Ultrastructure of plant chloroplasts was studied by a single-molecule spectroscopy setup at a temperature of 77 K exploring spatial location of photosystems. Two chloroplast thylakoid membrane regions were visualized by fluorescence microscopy and detected at different wavelengths. The size of these regions and the spatial resolution of the microscope allowed us to measure their chlorophyll fluorescence emission spectra of these membrane domains. While the grana regions are characterized by a predominant presence of Photosystem II pigment-protein complexes emitting at 685 nm, Photosystem I complexes are localized in stroma regions and emit at 730 nm.

  12. VERTEX: biological implications of total attenuation and chlorophyll and phycoerythrin fluorescence distributions along a 2000 m deep section in the Gulf of Alaska

    Science.gov (United States)

    Broenkow, William W.; Yuen, Marilyn A.; Yarbrough, Mark A.

    1992-04-01

    A 2000 m deep section of total attenuation and chlorophyll and phycoerythrin fluorescence from 26° to 59°N latitude in the northeast Pacific is discussed in terms of inferred biological processes. Photic zone distributions of these quantities vary from nutrient-limited conditions in the subtropics to light-limited conditions in the subarctic. Phycoerythrin-containing organisms, probably Synechococcus, contribute to a strong, near-surface orange fluorescence signal in the Gulf of Alaska. We now recognize that the fluorescence minimum (about 300 m) between the photic zone and the tertiary fluorescence maximum may be related to secondary producers that "repackage" organic matter produced in the photic zone. The tertiary fluorescence maximum (about 1000 m) is a continuous feature of the oxygen minimum zone in the North Pacific. The presence of phycoerythrin in the tertiary maximum is consistent with heterotrophic cyanobacteria and other unidentified microbial assemblages in the oxygen minimum, though there is no strong biological evidence that this is true.

  13. Consistent space-based retrievals of chlorophyll fluorescence and atmospheric CO2 and CH4 for improved estimates of carbon fluxes

    OpenAIRE

    Hahne, Philipp

    2015-01-01

    Understanding the natural carbon cycle and its feedback to climate change requires atmospheric carbon observations to constrain carbon surface fluxes. The retrieval method RemoTeC uses satellite measurements to retrieve atmospheric CO2 and CH4. This work improves the retrieval such that it accounts for chlorophyll fluorescence. Furthermore, this work shows that the CO2 retrieval accounting for chlorophyll fluorescence provides observational constraints on carbon surface flux estimates.

  14. 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 ...

  15. Global retrieval of marine and terrestrial chlorophyll fluorescence at its red peak using hyperspectral top of atmosphere radiance measurements: Feasibilirty study and first results.

    OpenAIRE

    Wolanin, Aleksandra; Rozanov, V. V.; S. Noël; Dinter, Tilman; Vountas, M.; J. P. Burrows; Bracher, Astrid

    2015-01-01

    Chlorophyll fluorescence is directly linked to the physiology of phytoplankton or plants. Here, we present a new satellite remote sensing approach to retrieve chlorophyll fluorescence at its red peak (~ 685 nm) by using measurements from the hyperspectral instruments SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) and Global Ozone Monitoring Experiment-2 (GOME-2). This method, which is based on the Differential Optical Absorption Spectroscopy (DOAS) technique...

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

    Directory of Open Access Journals (Sweden)

    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. Vegetation Red-edge Spectral Modeling for Solar-induced Chlorophyll Fluorescence Retrieval at O2-B Band

    Science.gov (United States)

    Huang, C.; Zhang, L.; Qiao, N.; Zhang, X.; Li, Y.

    2015-12-01

    Remotely sensed solar-induced chlorophyll fluorescence (SIF) has been considered an ideal probe in monitoring global vegetation photosynthesis. However, challenges in accurate estimate of faint SIF (less than 5% of the total reflected radiation in near infrared bands) from the observed apparent reflected radiation greatly limit its wide applications. Currently, the telluric O2-B (~688nm) and O2-A (~761nm) have been proved to be capable of SIF retrieval based on Fraunhofer line depth (FLD) principle. They may still work well even using conventional ground-based commercial spectrometers with typical spectral resolutions of 2~5 nm and high enough signal-to-noise ratio (e.g., the ASD spectrometer). Nevertheless, almost all current FLD based algorithms were mainly developed for O2-A, a few concentrating on the other SIF emission peak in O2-B. One of the critical reasons is that it is very difficult to model the sudden varying reflectance around O2-B band located in the red-edge spectral region (about 680-800 nm). This study investigates a new method by combining the established inverted Gaussian reflectance model (IGM) and FLD principle using diurnal canopy spectra with relative low spectral resolutions of 1 nm (FluorMOD simulations) and 3 nm (measured by ASD spectrometer) respectively. The IGM has been reported to be an objective and good method to characterize the entire vegetation red-edge reflectance. Consequently, the proposed SIF retrieval method (hereinafter called IGMFLD) could exploit all the spectral information along the whole red-edge (680-800 nm) to obtain more reasonable reflectance and fluorescence correction coefficients than traditional FLD methods such as the iFLD. Initial results show that the IGMFLD can better capture the spectrally non-linear characterization of the reflectance in 680-800 nm and thereby yields much more accurate SIFs in O2-B than typical FLD methods, including sFLD, 3FLD and iFLD (see figure 1). Finally, uncertainties and prospect

  18. 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; Qin, Yuanwei; Wang, Jie; Moore, Berrien, III

    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.

  19. 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.

  20. 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.

  1. Underwater Optical Fiber Fluorescent System for Measuring Chlorophyll-a Concentration

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using optical fiber fluorescent technology,a new method for measuring alga concentration in water is presented. The system can realize on-line measurement for alga concentration using He-Ne laser as the light source. It can also effectively detect weak signals. The system with a passive sensor head has such advantages as simple structure, high sensitivity and high accuracy. It has been demonstrated that this system can be used to monitor water quality and can also be used to survey some matter.

  2. The drought impact on satellite solar-induced chlorophyll fluorescence in China during 2007-2015

    Science.gov (United States)

    Li, Ruitao

    2016-04-01

    Drought is one of the most damaging and complicated natural hazards in the world. China is one of the countries which are most severely affected by drought. And there is a severe drought event in China every 2-3 years. From the beginning of the 1980s, some vegetation indices have been used to monitor vegetation under water stress. With the development of remote sensing technology, satellite solar-induced chlorophyll fluorescence (SIF) has emerged as a new method to monitor vegetation in recent years. Some studies have shown that compared with vegetation indices, SIF is more sensitive for vegetation functioning. However, the related studies using the satellite SIF is relatively limited in China. The objective of this study is to investigate the impact of drought on SIF by analyzing the relationships of SIF and crucial land surface parameter under the drought condition and to assess the adaption of satellite SIF in China. The SIF data are from the Global Ozone Monitoring Experiment 2 (GOME-2). Firstly, the widely used Palmer Drought Severity Index (PDSI) was used for drought events identification from 2007 to 2015 in China. On the basis of the identification results, we chose a number of areas of interest according to different land cover types and drought intensity. Then, we analyzed the relationships of SIF and land surface variables, i.e. normalized difference vegetation index (NDVI), the fraction of absorbed photosynthetically active radiation (fPAR), root-zone soil moisture (SMC) and surface skin temperatures (Tskin). The results show that the spatial patterns of negative SIF anomalies are closely relevant to the drought intensity. The decrease of SIF is aggravated in the phase of drought occurs. Moreover we find that the GOME-2 SIF is sensitive to fPAR and fluorescence yield. And the SIF is strongly correlated with SMC, Tskin and NDVI. But the SIF decreases more rapidly during the early time of drought events than NDVI. In other words, the SIF can well capture

  3. Estimation of the depth of sunlight penetration in natural waters for the remote sensing of chlorophyll a via in vivo fluorescence

    Science.gov (United States)

    Gordon, H. R.

    1979-01-01

    In attempting to measure remotely the constituents of the ocean through spectral analysis of diffusely reflected sunlight, it is important to know the depth over which constituent concentrations can be estimated. Recently, considerable interest has been generated in the use of sunlight-excited fluorescence of chlorophyll a contained in photoplankton (in vivo) to determine remotely the chlorophyll a concentration in surface waters. In the present paper an estimate is provided for the depth to which chlorophyll a concentration can be determined from observations of the fluorescence.

  4. Valinomycin sensitivity proves that light-induced thylakoid voltages result in millisecond phase of chlorophyll fluorescence transients.

    Science.gov (United States)

    Pospísil, Pavel; Dau, Holger

    2002-04-22

    Upon sudden exposure of plants to an actinic light of saturating intensity, the yield of chlorophyll fluorescence increases typically by 200-400% of the initial O-level. At least three distinct phases of these O-J-I-P transients can be resolved: O-J (0.05-5 ms), J-I (5-50 ms), and I-P (50-1000 ms). In thylakoid membranes, the J-I increase accounts for approximately 30% of the total fluorescence increase; in Photosystem II membranes, the J-I phase is always lacking. In the presence of the ionophore valinomycin, which is known to inhibit specifically the formation of membrane voltages, the magnitude of the J-I phase is clearly diminished; in the presence of valinomycin supplemented by potassium, the J-I phase is fully suppressed. We conclude that the light-driven formation of the thylakoid-membrane voltage results in an increase of the chlorophyll excited-state lifetime, a phenomenon explainable by the electric-field-induced shift of the free-energy level of the primary radical pair [Dau and Sauer, Biochim. Biophys. Acta 1102 (1992) 91]. The assignment of the J-I increase in the fluorescence yield enhances the potential of using O-J-I-P fluorescence transients for investigations on photosynthesis in intact organisms. A putative role of thylakoid voltages in protection of PSII against photoinhibitory damage is discussed. PMID:12034474

  5. Monitoring the Photosynthetic Apparatus During Space Flight: Interspecific Variation in Chlorophyll Fluorescence Signatures Induced by Different Root Zone Stresses

    Science.gov (United States)

    Bubenheim, David L.; Patterson, Mark T.; Kliss, Mark H. (Technical Monitor)

    1996-01-01

    Chlorophyll fluorescence has been used extensively as a tool to indicate stress to the photosynthetic apparatus in green plants. A rise in fluorescence has been attributed to the blockage of photosystem II photochemistry, and patterns of fluorescence decay (quenching) from dark adapted leaves can be related to specific photochemical and non-photochemical deexcitation pathways of light trapped by the photosynthetic apparatus and thus result in characteristically different fluorescence signatures. Four distantly related plant species, Hypocharis radicata (Asteraceae), Brassica rapa (Brassicaceae), Spinacea oleracea (Chenopodiaceae) and Triticum aestivum (Poaceae), were grown hydroponically for three weeks before the initiation of three different root zone stresses (10 mM Cu, 100 mM NaCl and nitrogen deficient nutrition). After 10 days, characteristic fluorescence signatures for each stress could be noted although the degree varied between species. Fast kinetics analysis showed a reduction in plastoquinone pool size for copper and nitrogen stress for all species but a more species specific result with NaCl stress. Photochemical quenching kinetics varied between species and stress treatments from no quenching in S. oleracea in copper treatments to increased photochemical quenching in NaCl treatments. Non-photochemical quenching kinetics demonstrated a distinct pattern between stresses for all species. Copper treatments characteristically exhibited a shallow, flat non-photochemical quenching profile suggesting a general blockage of electron transport whereas NaCl treatments exhibited a slow rising profile that suggested damage to thylakoid acidification kinetics and nitrogen deficiency exhibited a fast rising and declining profile that suggested an altered state 1-state 2 transition regulated by the phosphorylation of LHCII. These results demonstrate characteristic fluorescence signatures for specific plant stresses that may be applied to different, unrelated plant

  6. Satellite chlorophyll fluorescence measurements reveal large-scale decoupling of photosynthesis and greenness dynamics in boreal evergreen forests.

    Science.gov (United States)

    Walther, Sophia; Voigt, Maximilian; Thum, Tea; Gonsamo, Alemu; Zhang, Yongguang; Köhler, Philipp; Jung, Martin; Varlagin, Andrej; Guanter, Luis

    2016-09-01

    Mid-to-high latitude forests play an important role in the terrestrial carbon cycle, but the representation of photosynthesis in boreal forests by current modelling and observational methods is still challenging. In particular, the applicability of existing satellite-based proxies of greenness to indicate photosynthetic activity is hindered by small annual changes in green biomass of the often evergreen tree population and by the confounding effects of background materials such as snow. As an alternative, satellite measurements of sun-induced chlorophyll fluorescence (SIF) can be used as a direct proxy of photosynthetic activity. In this study, the start and end of the photosynthetically active season of the main boreal forests are analysed using spaceborne SIF measurements retrieved from the GOME-2 instrument and compared to that of green biomass, proxied by vegetation indices including the Enhanced Vegetation Index (EVI) derived from MODIS data. We find that photosynthesis and greenness show a similar seasonality in deciduous forests. In high-latitude evergreen needleleaf forests, however, the length of the photosynthetically active period indicated by SIF is up to 6 weeks longer than the green biomass changing period proxied by EVI, with SIF showing a start-of-season of approximately 1 month earlier than EVI. On average, the photosynthetic spring recovery as signalled by SIF occurs as soon as air temperatures exceed the freezing point (2-3 °C) and when the snow on the ground has not yet completely melted. These findings are supported by model data of gross primary production and a number of other studies which evaluated in situ observations of CO2 fluxes, meteorology and the physiological state of the needles. Our results demonstrate the sensitivity of space-based SIF measurements to light-use efficiency of boreal forests and their potential for an unbiased detection of photosynthetic activity even under the challenging conditions interposed by evergreen

  7. Vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: a first database for the global ocean

    Science.gov (United States)

    Sauzède, R.; Lavigne, H.; Claustre, H.; Uitz, J.; Schmechtig, C.; D'Ortenzio, F.; Guinet, C.; Pesant, S.

    2015-10-01

    In vivo chlorophyll a fluorescence is a proxy of chlorophyll a concentration, and is one of the most frequently measured biogeochemical properties in the ocean. Thousands of profiles are available from historical databases and the integration of fluorescence sensors to autonomous platforms has led to a significant increase of chlorophyll fluorescence profile acquisition. To our knowledge, this important source of environmental data has not yet been included in global analyses. A total of 268 127 chlorophyll fluorescence profiles from several databases as well as published and unpublished individual sources were compiled. Following a robust quality control procedure detailed in the present paper, about 49 000 chlorophyll fluorescence profiles were converted into phytoplankton biomass (i.e., chlorophyll a concentration) and size-based community composition (i.e., microphytoplankton, nanophytoplankton and picophytoplankton), using a method specifically developed to harmonize fluorescence profiles from diverse sources. The data span over 5 decades from 1958 to 2015, including observations from all major oceanic basins and all seasons, and depths ranging from the surface to a median maximum sampling depth of around 700 m. Global maps of chlorophyll a concentration and phytoplankton community composition are presented here for the first time. Monthly climatologies were computed for three of Longhurst's ecological provinces in order to exemplify the potential use of the data product. Original data sets (raw fluorescence profiles) as well as calibrated profiles of phytoplankton biomass and community composition are available on open access at PANGAEA, Data Publisher for Earth and Environmental Science. Raw fluorescence profiles: http://doi.pangaea.de/10.1594/PANGAEA.844212 and Phytoplankton biomass and community composition: http://doi.pangaea.de/10.1594/PANGAEA.844485

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

    Science.gov (United States)

    Li, Tianyu; Zhang, Ye; Gong, Nan; Li, Zuowei; Sun, Chenglin; Men, Zhiwei

    2016-01-01

    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. PMID:27338363

  9. 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.

  10. Comparison of sun-induced chlorophyll fluorescence estimates from commercial spectroradiometers: an optimal setup for field measurement and aerial product validation.

    Science.gov (United States)

    Celesti, Marco; Rossini, Micol; Cogliati, Sergio; Panigada, Cinzia; Tagliabue, Giulia; Fava, Francesco; Julitta, Tommaso; MacArthur, Alasdair; Colombo, Roberto

    2016-04-01

    Sun-induced chlorophyll fluorescence signal is explored as a novel remote sensing method, notable for its potential to be used as a direct indicator of photosynthetic efficiency. In the last years, there was an increasing interest of the scientific community on the remote sensing of Sun-Induced chlorophyll Fluorescence (SIF). Several SIF estimates in the far-red region have been produced from spaceborne sensors, and the future FLEX satellite mission (European Space Agency, Earth-Explorer 8) aims to detect canopy level SIF in both red and far-red regions at global scale. In the context of FLEX calibration/validation activities, a network of ground station to calibrate/validate SIF estimates from space can be considered crucial, but few studies have proposed optimal technical requirements for commercially available spectroradiometers. At canopy level, SIF is traditionally retrieved from incoming and upwelling radiance measurements, exploiting two narrow oxygen absorption bands, within the O2-B and O2-A spectral regions. Only recently, the feasibility of retrieving the SIF spectrum was demonstrated. The rationale behind the exploitation of narrow spectral regions, characterized by strong absorptions, resides in the higher contribution of SIF with respect to the reflected radiance. In order to detect the signal in those narrow spectral regions, high spectral resolution observation is needed. In this study, we compared several high resolution field spectroradiometers with different Full Width at Half Maximum (FWHM), Spectral Sampling Interval (SSI) and Signal-to-Noise Ratio (SNR), to evaluate their performance in SIF estimates. We applied several state-of-the-art, radiance-based retrieval algorithms to radiance measurements taken with the FluoWAT. This device allows to measure leaf reflected and transmitted radiance, solar incident radiance and, upward and downward leaf fluorescence spectrum by means of a low pass filter, that were used as a reference.. Results show

  11. 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

  12. Effects of ozone exposure or fungal pathogen on white lupin leaves as determined by imaging of chlorophyll a fluorescence.

    Science.gov (United States)

    Guidi, Lucia; Mori, Sauro; Degl'Innocenti, Elena; Pecchia, Susanna

    2007-01-01

    Chlorophyll fluorescence has been used routinely to investigate photosynthetic activity in plants subjected to both biotic and abiotic stresses. The aim of this work was to compare the perturbations in photosynthesis induced by ozone and by a pathogen. By using a conventional fluorometer a similar response pattern was observed in inoculated and O(3)-fumigated leaves. The application of chlorophyll fluorescence imaging provided further detailed information on the spatial-temporal heterogeneity of the response of white lupin leaves to fungal pathogen or to ozone fumigation. In particular, 48 h after artificial inoculation with the necrotrophic fungal pathogen Pleiochaeta setosa, the leaves showed a remarkable alteration in PSII operating efficiency (Phi(PSII)), which affected the whole surface. Afterwards, the infection site was surrounded by a ring of increased photosynthetic activity. The response of ozonated leaves was quite different. The reduction in Phi(PSII) was already evident 24h after fumigation; moreover, a distinct heterogeneity of the fluorescence yield was observed and the major veins displayed a lowered Phi(PSII). PMID:17900916

  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 fluoromete

  14. Effects of ozone on photosynthetic CO{sub 2} exchange, chlorophyll a fluorescence and intioxidant systems in lettuce leaves

    Energy Technology Data Exchange (ETDEWEB)

    Calatayud, A.; Ramirez, J.W.; Barreno, E. [Univ. de Valencia, Inst. Facultad de Ciencias Biologicas, Burjasot (Spain); Iglesias, D.J. [Dpto. Citricultura Inst. Valenciano de Investigaciones Agrarias, Valencia (Spain)

    2002-11-01

    The effects of ozone exposure on lettuce leaves were investigated by means of gas exchange, modulated chlorophyll a fluorescence and antioxidants systems. High ozone concentration decreased the rate of photosynthesis at light saturation level and changes in stomatal conductance and transpiration rate. However, an increase in intercellular CO{sub 2} concentration indicated a decrease in the carboxylation efficiency. These data agreed with a reduction of non-cyclic electron flow and lower capacity to reduce the quinone pool. Ozone affected the ascorbate pool and decreased ascorbate peroxidase activity, increased lipid peroxidation, altered membrane properties and reduced the development of non-photochemical quenching. (au)

  15. Gas Exchange, Chlorophyll Fluorescence and Antioxidants as Bioindicators of Airborne Heavy Metal Pollution in Jeddah, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    I.A. Hassan

    2013-08-01

    Full Text Available Lettuce (Lactuca sativa L. cv. Romaine plants were exposed to different levels of urbanization in Jeddah city, Saudi Arabia. They showed different degrees of visible injury symptoms and dramatic changes in enzymatic activities as well as net photosynthetic rates (PN, variable to maximum chlorophyll fluorescence (Fv/Fm and stomatal conductance (gs.Visual symptoms of phytotoxicity of heavy metals were observed on plants grown at industrial and urban areas, where the concentrations of metals was about 36 times higher than in other sites. The decrease in chlorophyll reached 70 and 64% in plants cultivated in the industrial and urban regions, while lengths of shoots reduced by 50 and 41% in plants collected from the same locations, respectively. The reduction in chlorophyll and other physiological and biochemical parameters were correlated with the concentrations of airborne pollutants measured in the atmosphere of the locations examined. Moreover, lettuce plants cultivated in the industrial region accumulated more heavy metals than others, which can pass into the human food chain.Photosynthetic efficiency was significantly decreased and lipid peroxidation was enhanced. Antioxidant enzymes were significantly altered during exposure.The biochemical and physiological parameters measured in the present study clearly showed that they could form the basis of a plant biomarkers battery for monitoring and predicting early effects of exposure to airborne heavy metals.

  16. Spectral analysis on origination of the bands at 437 nm and 475.5 nm of chlorophyll fluorescence excitation spectrum in Arabidopsis chloroplasts.

    Science.gov (United States)

    Zeng, Lizhang; Wang, Yongqiang; Zhou, Jun

    2016-05-01

    Chlorophyll fluorescence has been often used as an intrinsic optical molecular probe to study photosynthesis. In this study, the origin of bands at 437 and 475.5 nm in the chlorophyll fluorescence excitation spectrum for emission at 685 nm in Arabidopsis chloroplasts was investigated using various optical analysis methods. The results revealed that this fluorescence excitation spectrum was related to the absorption characteristics of pigment molecules in PSII complexes. Moreover, the excitation band centred at 475.5 nm had a blue shift, but the excitation band at 437 nm changed relatively less due to induction of non-photochemical quenching (NPQ). Furthermore, fluorescence emission spectra showed that this blue shift occurred when excitation energy transfer from both chlorophyll b (Chl b) and carotenoids (Cars) to chlorophyll a (Chl a) was blocked. These results demonstrate that the excitation band at 437 nm was mainly contributed by Chl a, while the excitation band at 475.5 nm was mainly contributed by Chl b and Cars. The chlorophyll fluorescence excitation spectrum, therefore, could serve as a useful tool to describe specific characteristics of light absorption and energy transfer between light-harvesting pigments. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26358732

  17. 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

    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......We examined the effect of light emitting diode (LED) lighting in greenhouse facilities on growth, chlorophyll fluorescence and pigmentation in Phalaenopsis 'Vivien' and 'Purple Star' under purpose-built LED arrays yielding c. 200μmolm-2s-1 at plant height for 14h per day and 24/18°Cday...... 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...

  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...... responses of the same cultivars to heat stress were compared between the two methods of heat treatment. The results showed that in detached leaves, all of the fluorescence parameters remained almost unaffected in control (20°C at all durations tested), indicating that the detachment itself did not affect...... 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...

  19. 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.

  20. 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: 6.393, year: 2014

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

    OpenAIRE

    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 fluorometer revealed that the efficiency of photosystem II decreased both with increasing time of UV-B radiation and with increasing intensity of the UV-B. Fluorescence induction rise curves were analyzed us...

  2. 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. PMID:27161580

  3. 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.

  4. Effects of Nitrogen Fertilizer Level on Chlorophyll Fluorescence Characteristics in Flag Leaf of Super Hybrid Rice at Late Growth Stage

    Institute of Scientific and Technical Information of China (English)

    LONG Ji-rui; MA Guo-hui; WAN Yi-zheng; SONG Chun-fang; SUN Jian; QIN Rui-jun

    2013-01-01

    To compare the effects of slow-release nitrogen fertilizer at six different levels on the flag leaf chlorophyll fluorescence characteristics of super hybrid rice,a field fertilization experiment was conducted with super hybrid rice Y Liangyou 1 as a test material.The photosynthetic electron transport rate (ETR),effective quantum yield (EQY),photochemical quenching coefficient (qp),and non-photochemical quenching coefficient (NPQ) of flag leaves were measured at the initial heading,full heading,10 d after full heading and 20 d after full heading stages.Results showed that the values of ETR,EQY and qp increased with rice development from initial heading to 20 d after full heading,whereas the NPQ decreased.During the measured stages,ETR,EQY and qp increased initially and then decreased as nitrogen application amount increased,but they peaked at different nitrogen fertilizer levels.The maximum ETR and EQY values appeared at the treatment of 135 kg/hm2 N.In conclusion,the optimum nitrogen amount for chlorophyll fluorescence characteristics of super hybrid rice was 135-180 kg/hm2.

  5. Photosynthesis monitoring to optimize growth of microalgal mass cultures: application of chlorophyll fluorescence techniques

    Czech Academy of Sciences Publication Activity Database

    Malapascua, José R.F.; Jerez, Celia G.; Sergejevova, Magda; Figueroa, Felix L.; Masojídek, Jiří

    2014-01-01

    Roč. 22, č. 2014 (2014), s. 123-140. ISSN 1864-7790 R&D Projects: GA MŠk ED2.1.00/03.0110; GA MŠk EE2.3.30.0059 Grant ostatní: ACTION(AT) CTM2011-15659-E Institutional support: RVO:61388971 Keywords : chlorophyll * biomass * photosynthesis Subject RIV: EE - Microbiology, Virology Impact factor: 1.258, year: 2014

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

    OpenAIRE

    García-Sánchez, M. A.; I. N. Serratos; R. Sosa; T. Tapia-Esquivel; F. González-García; F. Rojas-González; S. R. Tello-Solís; A. Y. Palacios-Enriquez; J. M. Esparza Schulz; A. Arrieta

    2016-01-01

    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 ...

  7. Assessment of salt tolerance of some newly developed and candidate wheat (triticum aestivum l.) cultivars using gas exchange and chlorophyll fluorescence attributes

    International Nuclear Information System (INIS)

    The present study was aimed to assess salt tolerance of some newly developed and candidate cultivars of wheat using gas exchange and chlorophyll fluorescence parameters. Ten wheat cultivars including five newly developed (S-24, Saher-2006, Fsd-2008, Lasani and Inqlab-91) and five candidate (P .B-18, M.P-65, S.H-20, AARI-10 and G.A-20) were grown in sand culture. Salt stress (150 mM NaCl in Hoagland's nutrient solution) was applied at the seedling stage. A significant reduction in plant biomass production was recorded in all wheat cultivars. Cultivars S-24, Saher-2006 and Fsd-2008 showed less reduction in biomass production as compared with the other cultivars. Different gas exchange attributes such as leaf net photosynthetic rate (A), transpiration rate ( E), and stomatal conductance (gs) were also adversely affected due to salt stress and were positively associated with the plant biomass production of the genotypes under saline stress. More negative effects in relation to these gas exchange attributes were recorded in cvs. Lasani, G.A-20 and ARRI-10 than those in the other cultivars. Leaf maximum chlorophyll fluorescence (Fm), maximum fluorescence at steady state (Fms ), and photochemical fluorescence quenching (Qp) increased while maximum quantum yield (Fv/Fm), quantum yield of electron transport (Qp), electron transport rate ( ETR ) and non-photochemical quenching (Qn) decreased due to imposition of salt stress. The adverse effects of salt stress on these chlorophyll fluorescence attributes were minimum in cultivars S-24, Saher-2006 and Fsd-2008. A significant positive correlation was recorded between biomass production, different gas exchange attributes and chlorophyll fluorescence parameters. Overall, cvs. S-24, Saher-2006 and Fsd-2008 were ranked as salt tolerant on the basis of their performance in biomass production, gas exchange attributes and chlorophyll fluorescence parameters. (author)

  8. 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.; Berry, J.; Lee, J. -E.; Walker, G.; Reichle, R.; Lyapustin, A.; Joiner, J.; Tucker, C.; Koster, R.; 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).

  9. Natural faecal fluorophores and the potential of chlorophyll based markers to optimise fluorescence as a real-time solution for the detection of faecal contamination on carcasses.

    Science.gov (United States)

    Lee, M R F; Theobald, V J; Ougham, H J; Dahl, A Veberg; Lundby, F; Scollan, N D; Wold, J-P

    2010-12-01

    More accurate and sensitive visualisation of faecal contamination in the abattoir would significantly reduce the risk posed by harbouring pathogenic micro-organisms. We carried out a preliminary investigation of the range of fluorophores found naturally in faeces from typical ruminant diets. Sixteen ewes were offered either: i) fresh forage (FF), ii) grass silage (GS), iii) grass hay (GH) or iv) concentrate and barley straw (CB). Animals offered FF diets had a greater concentration (PSpirulina (Chlorophyll a extract from blue green algae, Sp). The last group received no supplement as the control (Con). The appearance of chlorophyllin markers and their derivatives in faeces was similar with mean concentrations of 3.1 and 7.2 μg/g DM, respectively. The most intense fluorescent signal was shown with MgC followed by ZnC, FeC, Sp and Con at 685 nm. The use of markers in pre-slaughter diets would improve the accuracy of faecal detection as a result of greater fluorescence and specific emission wavelengths which do not overlap with natural meat components to help with visualisation. PMID:20813464

  10. Experimental effects of sand-dust storm on tolerance index, percentage phototoxicity and chlorophyll a fluorescence of Vigna radiata L.

    Directory of Open Access Journals (Sweden)

    M. Alavi

    2015-03-01

    Full Text Available In arid and semi-arid parts of the world excessive mineral aerosol carried by air parcels is a common climatic incident with well-known environmental side effects. In this way, we studied the role of sand-dust accumulation on various aspects of productivity of Vigna radiata L. including dry mass (DM, chlorophyll (Chl a, b, Chlorophyll a fluorescence (effective quantum yield of PSII photochemistry (ФPSII, maximal quantum yield of PSII photochemistry (Fv/Fm and electron transport rate (ETR. V. radiata was exposed to a gradient of dust concentrations in a dust chamber (0.5 (T1, 1(T2 and 1.5 g/m3 (T3 simulated by a dust generator for a period of 60 days. Results of this experiment indicate that DM and Chl content of shoot are negatively correlated with the intensity of the dust exposure. Exposure of V. radiata to dust compared with the control was caused 5% (T1, 14% (T2 and 27% (T3 reduction in leaf DM (p≤0.05, ANOVA. Also, exposure to the dust induced a significant (p≤0.05 reduction in the Total Chl content in (T3 25%. Also, we showed that ФPSII, ETR and Fv/Fm were affected by increasing of the dust concentrations. Exposure to the dust resulted in a significant reduction in ETR of 15%, 22%, and 43%.

  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.; Gu, L.; Marchesini, L. Belelli

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

    International Nuclear Information System (INIS)

    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, O3 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 O3 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 O3 conductance. - Leaves of birch were more affected by ozone fumigation than corresponding stems, due to a higher ozone uptake rate

  13. [Extraction and analysis of solar-induced chlorophyll fluorescence of wheat with ground-based hyperspectral imaging system].

    Science.gov (United States)

    Wang, Ran; Liu, Zhi-gang; Feng, Hai-kuan; Yang, Pei-qi; Wang, Qing-shan; Ni, Zhuo-ya

    2013-09-01

    Dataset simulated with FluorMOD and images of wheat in heading stage taken by a ground-based hyperspectral imaging system with 3.3 nm spectral resolution and 0. 71-0. 74 nm spectral sampling interval were used test the feasibility and accuracy of three FLD methods (named FLD, 3FLD and iFLD). The results show that when spectral resolution is 3.3 nm, solar-induced chlorophyll fluorescence could be extracted effectively in O2-A band (around 760 nm) instead of O2-B band (around 687 nm). As to the extraction results of data with noises, both FLD and 3FLD are stabler than iFLD method. The results of FLD tend to be higher than true value. PMID:24369651

  14. Remote sensing of near-infrared chlorophyll fluorescence from space in scattering atmospheres: implications for its retrieval and interferences with atmospheric CO2 retrievals

    OpenAIRE

    J. McDuffie; L. Guanter; C. O'Dell; C. Frankenberg

    2012-01-01

    With the advent of dedicated greenhouse gas space-borne spectrometers sporting high resolution spectra in the O2 A-band spectral region (755–774 nm), the retrieval of chlorophyll fluorescence has become feasible on a global scale. If unaccounted for, however, fluorescence can indirectly perturb the greenhouse gas retrievals as it perturbs the oxygen absorption features. As atmospheric CO2 measurements are used to invert net fluxes at the land–atmosphere interface, a bias caused by fluore...

  15. Analysis of Red and Far-Red Sun-Induced Chlorophyll Fluorescence and Their Ratio in Different Canopies Based on Observed and Modeled Data

    OpenAIRE

    Micol Rossini; Michele Meroni; Marco Celesti; Sergio Cogliati; Tommaso Julitta; Cinzia Panigada; Uwe Rascher; Christiaan van der Tol; Roberto Colombo

    2016-01-01

    Sun-induced canopy chlorophyll fluorescence in both the red (FR) and far-red (FFR) regions was estimated across a range of temporal scales and a range of species from different plant functional types using high resolution radiance spectra collected on the ground. Field measurements were collected with a state-of-the-art spectrometer setup and standardized methodology. Results showed that different plant species were characterized by different fluorescence magnitude. In general, the highest fl...

  16. Detection of water stress in orchard trees with a high-resolution spectrometer through Chlorophyll fluorescence in-filling of the O-2-A band

    OpenAIRE

    Miller, John R.; Pérez-Priego, Óscar; Zarco-Tejada, Pablo J.; Fereres Castiel, Elías; Sepulcre-Cantó, Guadalupe

    2005-01-01

    A high spectral resolution spectrometer with 0.065-nm full-width half-maximum was used for collecting spectral measurements in an orchard field under three water stress treatments. The study was part of the FluorMOD project funded by the European Space Agency to develop a leaf-canopy reflectance model to simulate the effects of fluorescence. Water deficit protocols generated a gradient in solar-induced Chlorophyll fluorescence emission and tree physiological measures. Diurnal steady-state Chl...

  17. 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

  18. 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...

  19. Responses of ‘d’Anjou’ Pear (Pyrus communis L.) fruit to storage at low oxygen setpoints determined by monitoring fruit chlorophyll fluorescence

    Science.gov (United States)

    ‘d’Anjou’ pears, a superficial scald-susceptible cultivar, were stored in air or controlled atmospheres containing 1.5 kPa O2 or a minimal partial pressure determined using real-time monitoring of fruit chlorophyll fluorescence. In two experiments, the low O2 setpoints were 0.4 and 0.5 kPa. During...

  20. Chlorophyll a fluorescence as a tool for a study of the Potato virus Y effects on photosynthesis of nontransgenic and transgenic Pssu-ipt tobacco

    Czech Academy of Sciences Publication Activity Database

    Spoustová, Petra; Synková, Helena; Valcke, R.; Čeřovská, Noemi

    2013-01-01

    Roč. 51, č. 2 (2013), s. 191-201. ISSN 0300-3604 Institutional research plan: CEZ:AV0Z50380511 Keywords : gas-exchange parameters * cytokinins * chlorophyll a fluorescence imaging Subject RIV: EF - Botanics Impact factor: 1.007, year: 2013

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

    International Nuclear Information System (INIS)

    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.

  2. Diurnal changes in chlorophyll fluorescence and light utilization in Colocasia esculenta leaves grown in marshy waterlogged area

    International Nuclear Information System (INIS)

    Diurnal cycle of chlorophyll fluorescence was evaluated in Colocasia esculenta grown in marshy land under sun or under shade. The sun leaves maintained higher electron transport rate (ETR) and steady state to initial fluorescence ratio (Fs/F0) than shade leaves. In spite of lower ETR, higher photochemical quenching (PQ) and effective quantum yield of photosystem 2 (PS 2) was evident in shade plants compared to plants exposed to higher irradiance. ETR increased linearly with increase in irradiance more under low irradiance (r2 = 0.84) compared to higher irradiance (r2 = 0.62). The maximum quantum yield of PS 2 (Fv/Fm) did not differ much in sun and shade leaves with the exception of midday when excess of light energy absorbed by plants under sun was thermally dissipated. Hence swamp taro plants adopted different strategies to utilize radiation under different irradiances. At higher irradiance, there was faster decline in proportion of open PS 2 centers (PQ) and excess light energy was dissipated through non-photochemical quenching. Under shade, absorbed energy was effectively utilized resulting in higher PS2

  3. Red and far red Sun-induced chlorophyll fluorescence as a measure of plant photosynthesis

    Czech Academy of Sciences Publication Activity Database

    Rossini, P. M.; Nedbal, L.; Guanter, L.; Ač, Alexander; Alonso, L.; Burkart, A.; Cogliati, S.; Colombo, R.; Damm, A.; Drusch, M.; Hanuš, Jan; Janoutová, Růžena; Julitta, T.; Kokkalis, P.; Moreno, J.; Novotný, Jan; Panigada, C.; Pinto, F.; Schickling, A.; Schuettemeyer, D.; Zemek, František; Rascher, U.

    2015-01-01

    Roč. 42, č. 6 (2015), s. 1632-1639. ISSN 0094-8276 Institutional support: RVO:67179843 Keywords : sun-induced fluorescence * remote sensing * stress detection * airborne images * HyPlant Subject RIV: EH - Ecology, Behaviour Impact factor: 4.456, year: 2013

  4. Early fluorescence signals detect transitions at mammalian serotonin transporters.

    OpenAIRE

    Li, Ming; Lester, Henry A.

    2002-01-01

    The mammalian serotonin transporters rSERT or hSERT were expressed in oocytes and labeled with sulforhodamine-MTS. The endogenous Cys-109 residue contributes most of the signal, and the labeled transporter shows normal function. The SERT fluorescence decreases in the presence of 5-HT and also depends on the inorganic substrates of SERT. The fluorescence also increases with membrane depolarization. During voltage-jump experiments, fluorescence relaxations show little inactivation or history de...

  5. The Validity Chlorophyll-a Estimation by Sun Induced Fluorescence in Estuarine Waters: An Analysis of Long-term (2003-2011) Water Quality Data from Tampa Bay, Florida (USA)

    Science.gov (United States)

    Moreno-Madrinan, Max Jacobo; Fischer, Andrew

    2012-01-01

    Satellite observation of phytoplankton concentration or chlorophyll-a 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 chlorophyll-a inaccurate. Measurement of sun-induced 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 baseline algorithms based on the sun induced chlorophyll fluorescence signal, few have examined the empirical validity of these algorithms using a comprehensive long term in situ data set. In an unprecedented analysis of a long term (2003-2011) in situ monitoring data from Tampa Bay, Florida (USA), we assess the validity of the FLH product from the Moderate Resolution Imaging Spectrometer (MODIS) against chlorophyll ]a and a suite of water quality parameters taken in a variety of conditions throughout a large optically complex estuarine system. A systematic analysis of sampling sites throughout the bay is undertaken to understand how the relationship between FLH and in situ chlorophyll-a responds to varying conditions within the estuary including water depth, distance from shore and structures and eight water quality parameters. From the 39 station for which data was derived, 22 stations showed significant correlations when the FLH product was matched with in situ chlorophyll-alpha data. The correlations (r2) for individual stations within Tampa Bay ranged between 0.67 (n=28, pless than 0.01) and-0.457 (n=12, p=.016), indicating that

  6. Electron-Vibrational Coupling and Fluorescence Spectra of Tetra-, Penta-, and Hexacoordinated Chlorophylls c1 and c2.

    Science.gov (United States)

    Etinski, Mihajlo; Petković, Milena; Ristić, Miroslav M; Marian, Christel M

    2015-08-13

    Chlorophylls (Chls) are a group of pigments related to light absorption, excitation energy, and electron transfer in photosynthetic complexes. Given the importance of intramolecular nuclear motion for these electronic processes, many experimental studies were performed in order to relate its coupling to electronic coordinates of these pigments, but a detailed analysis is still lacking for isolated Chls c1 and c2. To gain insight into the intramolecular motion and fluoroscence spectra of these two pigments in tetra-, penta-, and hexacoodinated states, we performed a quantum chemical study based on density functional theory and multimode harmonic approximation with displaced, distorted, and rotated normal modes. In order to benchmark the employed methods, we simulated the high-resolution fluorescence spectra of tetracoodinated Chls a, b, and d and compared them with available experimental spectra obtained with fluorescence line-narrowing techniques. Although the experimental spectra were obtained for ligand coordinated Chls, qualitatively good agreement was found between the simulated and experimental spectra. Almost all resonances were reproduced in the spectroscopically interesting region from 200 to 1700 cm(-1). The significance of mode distortion and rotation for the simulated spectra is discussed. The fluorescence spectra of Chls c1 and c2 consist of a group of peaks in the 200-450 cm(-1) spectral range, a group of weak peaks from 700 to 1000 cm(-1), and a large group of strong peaks from 1100 to 1600 cm(-1). Ligand effects are also addressed, and a mode is identified as a sensitive probe for the coordination state of Chls c1 and c2. PMID:26189597

  7. Simultaneous time resolution of the emission spectra of fluorescent proteins and zooxanthellar chlorophyll in reef-building corals.

    Science.gov (United States)

    Gilmore, Adam M; Larkum, Anthony W D; Salih, Anya; Itoh, Shigeru; Shibata, Yutaka; Bena, Chiaki; Yamasaki, Hideo; Papina, Marina; Van Woesik, Robert

    2003-05-01

    Light is absorbed by photosynthetic algal symbionts (i.e. zooxanthellae) and by chromophoric fluorescent proteins (FP) in reef-building coral tissue. We used a streak-camera spectrograph equipped with a pulsed, blue laser diode (50 ps, 405 nm) to simultaneously resolve the fluorescence spectra and kinetics for both the FP and the zooxanthellae. Shallow water (corals showed rapidly decaying species and reciprocal rises in greener emission components indicating Förster resonance energy transfer (FRET) between FP populations. The energy transfer modes were around 250 ps, and the main decay modes of the acceptor FP were typically 1900-2800 ps. All zooxanthellae emitted similar spectra and kinetics with peak emission (approximately 683 nm) mainly from photosystem II (PSII) chlorophyll (chl) a. Compared with the FP, the PSII emission exhibited similar rise times but much faster decay times, typically around 640-760 ps. The fluorescence kinetics and excitation versus emission mapping indicated that the FP emission played only a minor role, if any, in chl excitation. We thus suggest the FP could only indirectly act to absorb, screen and scatter light to protect PSII and underlying and surrounding animal tissue from excess visible and UV light. We conclude that our time-resolved spectral analysis and simulation revealed new FP emission components that would not be easily resolved at steady state because of their relatively rapid decays due to efficient FRET. We believe the methods show promise for future studies of coral bleaching and for potentially identifying FP species for use as genetic markers and FRET partners, like the related green FP from Aequorea spp. PMID:12812294

  8. Influence of UV-B radiation and Cd2+ on chlorophyll fluorescence, growth and nutrient content in Brassica napus

    International Nuclear Information System (INIS)

    The possible interaction of two stresses, UV-B radiation and cadmium, applied simultaneously, was investigated in Brassica napus L. cv. Paroll with respect to chlorophyll fluorescence, growth and uptake of selected elements. Plants were grown in nutrient solution containing CdCl2, (0, 0.5, 2 or 5 μM) and irradiated with photosynthetically active radiation (PAR, 400–700 nm, 800 μmol m−2 s−1) with or without supplemental ultraviolet-B radiation (UV-B, 280–320 nm, 15 kJ m−2 d−1, weighted irradiance). After 14 d of treatment, the most pronounced effects were found at 2 and 5 μM CdCl2 with and without supplemental UV-B radiation. Exposure to cadmium significantly increased the amount of Cd in both roots and shoots. In addition, increases occurred in the concentration of Fe, Zn, Cu, and P in roots, while K was reduced. In shoots the S content rose significantly both in the presence and absence of UV-B radiation, while significant increases in Mg, Ca, P, Cu, and K occurred only in plants exposed to Cd and UV-B radiation. Manganese decreased significantly under the combined exposure treatment. The rise in S content may have been due to stimulated glutathione and phytochelatin synthesis. Cadmium exposure significantly decreased root dry weight, leaf area, total chlorophyll content, carotenoid content, and the photochemical quantum yield of photosynthesis. As an estimation of energy dissipation processes in photosynthesis, non photochemical quenching (qNPQ) was measured using a pulse amplitude modulated fluorometer. The qNPQ increased with increasing Cd, while the combination of cadmium and UV-B reduced the qNPQ compared to that in plants exposed only to cadmium or UV-B radiation. The chlorophyll a : b ratio showed a reduction with UV-B at no or low Cd concentrations (0 μM, 0.5 μM CdCl2), but not at the higher Cd concentrations used (2 μM, 5 μM CdCl2). Thus in some instances there appeared to be a UV-B and Cd interaction, while in others plant response

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

    OpenAIRE

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

    2012-01-01

    Understanding the ocean carbon cycle requires a precise assessment of phytoplankton biomass in the oceans. In terms of numbers of observations, satellite data represents 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 operate routinely on oceanographic cruise since the seventies. Nevertheless,...

  10. The interrelationship between the lower oxygen limit, chlorophyll fluorescence and the xanthophyll cycle in plants.

    Science.gov (United States)

    Wright, A Harrison; DeLong, John M; Gunawardena, Arunika H L A N; Prange, Robert K

    2011-03-01

    The lower oxygen limit (LOL) in plants may be identified through the measure of respiratory gases [i.e. the anaerobic compensation point (ACP) or the respiratory quotient breakpoint (RQB)], but recent work shows it may also be identified by a sudden rise in dark minimum fluorescence (F(o)). The interrelationship between aerobic respiration and fermentative metabolism, which occur in the mitochondria and cytosol, respectively, and fluorescence, which emanates from the chloroplasts, is not well documented in the literature. Using spinach (Spinacia oleracea), this study showed that F(o) and photochemical quenching (q(P)) remained relatively unchanged until O(2) levels dropped below the LOL. An over-reduction of the plastoquinone (PQ) pool is believed to increase F(o) under dark + anoxic conditions. It is proposed that excess cytosolic reductant due to inhibition of the mitochondria's cytochrome oxidase under low-O(2), may be the primary reductant source. The maximum fluorescence (F(m)) is largely unaffected by low-O(2) in the dark, but was severely quenched, mirroring changes to the xanthophyll de-epoxidation state (DEPS), under even low-intensity light (≈4 μmol m(-2) s(-1)). In low light, the low-O(2)-induced increase in F(o) was also quenched, likely by non-photochemical and photochemical means. The degree of quenching in the light was negatively correlated with the level of ethanol fermentation in the dark. A discussion detailing the possible roles of cyclic electron flow, the xanthophyll cycle, chlororespiration and a pathway we termed 'chlorofermentation' were used to interpret fluorescence phenomena of both spinach and apple (Malus domestica) over a range of atmospheric conditions under both dark and low-light. PMID:21290261

  11. Can CO2 assimilation in maize leaves be predicted accurately from chlorophyll fluorescence analysis?

    Science.gov (United States)

    Edwards, G E; Baker, N R

    1993-08-01

    Analysis is made of the energetics of CO2 fixation, the photochemical quantum requirement per CO2 fixed, and sinks for utilising reductive power in the C4 plant maize. CO2 assimilation is the primary sink for energy derived from photochemistry, whereas photorespiration and nitrogen assimilation are relatively small sinks, particularly in developed leaves. Measurement of O2 exchange by mass spectrometry and CO2 exchange by infrared gas analysis under varying levels of CO2 indicate that there is a very close relationship between the true rate of O2 evolution from PS II and the net rate of CO2 fixation. Consideration is given to measurements of the quantum yields of PS II (φ PS II) from fluorescence analysis and of CO2 assimilation ([Formula: see text]) in maize over a wide range of conditions. The[Formula: see text] ratio was found to remain reasonably constant (ca. 12) over a range of physiological conditions in developed leaves, with varying temperature, CO2 concentrations, light intensities (from 5% to 100% of full sunlight), and following photoinhibition under high light and low temperature. A simple model for predicting CO2 assimilation from fluorescence parameters is presented and evaluated. It is concluded that under a wide range of conditions fluorescence parameters can be used to predict accurately and rapidly CO2 assimilation rates in maize. PMID:24317706

  12. 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.

  13. Defects in leaf carbohydrate metabolism compromise acclimation to high light and lead to a high chlorophyll fluorescence phenotype in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Schmitz Jessica

    2012-01-01

    Full Text Available Abstract Background We have studied the impact of carbohydrate-starvation on the acclimation response to high light using Arabidopsis thaliana double mutants strongly impaired in the day- and night path of photoassimilate export from the chloroplast. A complete knock-out mutant of the triose phosphate/phosphate translocator (TPT; tpt-2 mutant was crossed to mutants defective in (i starch biosynthesis (adg1-1, pgm1 and pgi1-1; knock-outs of ADP-glucose pyrophosphorylase, plastidial phosphoglucomutase and phosphoglucose isomerase or (ii starch mobilization (sex1-3, knock-out of glucan water dikinase as well as in (iii maltose export from the chloroplast (mex1-2. Results All double mutants were viable and indistinguishable from the wild type when grown under low light conditions, but - except for sex1-3/tpt-2 - developed a high chlorophyll fluorescence (HCF phenotype and growth retardation when grown in high light. Immunoblots of thylakoid proteins, Blue-Native gel electrophoresis and chlorophyll fluorescence emission analyses at 77 Kelvin with the adg1-1/tpt-2 double mutant revealed that HCF was linked to a specific decrease in plastome-encoded core proteins of both photosystems (with the exception of the PSII component cytochrome b559, whereas nuclear-encoded antennae (LHCs accumulated normally, but were predominantly not attached to their photosystems. Uncoupled antennae are the major cause for HCF of dark-adapted plants. Feeding of sucrose or glucose to high light-grown adg1-1/tpt-2 plants rescued the HCF- and growth phenotypes. Elevated sugar levels induce the expression of the glucose-6-phosphate/phosphate translocator2 (GPT2, which in principle could compensate for the deficiency in the TPT. A triple mutant with an additional defect in GPT2 (adg1-1/tpt-2/gpt2-1 exhibited an identical rescue of the HCF- and growth phenotype in response to sugar feeding as the adg1-1/tpt-2 double mutant, indicating that this rescue is independent from the

  14. Signal Improvement Strategies for Fluorescence Detection of Biomacromolecules.

    Science.gov (United States)

    Luan, Chengxin; Yang, Zixue; Chen, Baoan

    2016-05-01

    For analysis of biomacromolecules, a sensitive, specified and reliable method is indispensable. Fluorescent dyes or fluorophores have been widely used as mediums to obtain readout signals in various assays or bioimaging because of their versatilities such as biocompatibility. Those fluorescent dyes based techniques manipulate many molecular interactions for analysis of biomacromolecules including antibody-protein interaction, base complementation, glycan-lectin interaction, etc. The strategies to manipulate those molecular interactions are various and always updating due to the development of biotechnological tools and instruments. In this minireview, we summarize the state of the art of signal improvement techniques for fluorescence detection of biomacromolecules especially proteins and nucleic acids. We focus on the principle and mechanism of those techniques for fluorescence detection of biomacromolecules. We also discuss the future trend of the techniques for fluorescence detection of biomacromolecules. PMID:27063869

  15. SIGNALS REGARDING THE ISOLATION OF CHLOROPHYL-FREE ALGAE IN THE MILK OF SOME HEALTHY COWS AND SOME WITH MAMITTIS

    OpenAIRE

    OGNEAN, Laurent; Dana PUSTA; Oana, Liviu

    2002-01-01

    In the microbiological investigation, made on samples of normal; (n=412) and mastitic (n=482) milk, proceeded from eight dairy cows farm, in Transilvania, it was signal the presence of the algae without chlorophyl belonging to Prototheca, forming together with bacteria and fungi the micro flora of the mammary gland. The alga content of normal milk was signaled only in two farms (2.27%, respectively 1.21%), being established to 0.72%. In the case of mastitic milk the percentage of ...

  16. Drought onset mechanisms revealed by satellite solar-induced chlorophyll fluorescence: Insights from two contrasting extreme events

    Science.gov (United States)

    Sun, Ying; Fu, Rong; Dickinson, Robert; Joiner, Joanna; Frankenberg, Christian; Gu, Lianhong; Xia, Youlong; Fernando, Nelun

    2015-11-01

    This study uses the droughts of 2011 in Texas and 2012 over the central Great Plains as case studies to explore the potential of satellite-observed solar-induced chlorophyll fluorescence (SIF) for monitoring drought dynamics. We find that the spatial patterns of negative SIF anomalies from the Global Ozone Monitoring Experiment 2 (GOME-2) closely resembled drought intensity maps from the U.S. Drought Monitor for both events. The drought-induced suppression of SIF occurred throughout 2011 but was exacerbated in summer in the Texas drought. This event was characterized by a persistent depletion of root zone soil moisture caused by yearlong below-normal precipitation. In contrast, for the central Great Plains drought, warmer temperatures and relatively normal precipitation boosted SIF in the spring of 2012; however, a sudden drop in precipitation coupled with unusually high temperatures rapidly depleted soil moisture through evapotranspiration, leading to a rapid onset of drought in early summer. Accordingly, SIF reversed from above to below normal. For both regions, the GOME-2 SIF anomalies were significantly correlated with those of root zone soil moisture, indicating that the former can potentially be used as proxy of the latter for monitoring agricultural droughts with different onset mechanisms. Further analyses indicate that the contrasting dynamics of SIF during these two extreme events were caused by changes in both fraction of absorbed photosynthetically active radiation fPAR and fluorescence yield, suggesting that satellite SIF is sensitive to both structural and physiological/biochemical variations of vegetation. We conclude that the emerging satellite SIF has excellent potential for dynamic drought monitoring.

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

    Directory of Open Access Journals (Sweden)

    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

    Science.gov (United States)

    Moriyuki, Shogo; Fukuda, Hirokazu

    2016-01-01

    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 plants at an early stage, using so-called seedlings 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 5000 lettuce plants every day. At an early stage (6 days after sowing), a CF image of 7200 seedlings was captured every 4 h 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. A linear method for the retrieval of sun-induced chlorophyll fluorescence from GOME-2 and SCIAMACHY data

    Science.gov (United States)

    Köhler, P.; Guanter, L.; Joiner, J.

    2015-06-01

    Global retrievals of near-infrared sun-induced chlorophyll fluorescence (SIF) have been achieved in the last few years by means of a number of space-borne atmospheric spectrometers. Here, we present a new retrieval method for medium spectral resolution instruments such as the Global Ozone Monitoring Experiment-2 (GOME-2) and the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY). Building upon the previous work by Guanter et al. (2013) and Joiner et al. (2013), our approach provides a solution for the selection of the number of free parameters. In particular, a backward elimination algorithm is applied to optimize the number of coefficients to fit, which reduces also the retrieval noise and selects the number of state vector elements automatically. A sensitivity analysis with simulated spectra has been utilized to evaluate the performance of our retrieval approach. The method has also been applied to estimate SIF at 740 nm from real spectra from GOME-2 and for the first time, from SCIAMACHY. We find a good correspondence of the absolute SIF values and the spatial patterns from the two sensors, which suggests the robustness of the proposed retrieval method. In addition, we compare our results to existing SIF data sets, examine uncertainties and use our GOME-2 retrievals to show empirically the relatively low sensitivity of the SIF retrieval to cloud contamination.

  20. Solar-induced chlorophyll fluorescence that correlates with canopy photosynthesis on diurnal and seasonal scales in a temperate deciduous forest

    Science.gov (United States)

    Yang, Xi; Tang, Jianwu; Mustard, John F.; Lee, Jung-Eun; Rossini, Micol; Joiner, Joanna; Munger, J. William; Kornfeld, Ari; Richardson, Andrew D.

    2015-04-01

    Previous studies have suggested that solar-induced chlorophyll fluorescence (SIF) is correlated with Gross Primary Production (GPP). However, it remains unclear to what extent this relationship is due to absorbed photosynthetically active radiation (APAR) and/or light use efficiency (LUE). Here we present the first time series of near-surface measurement of canopy-scale SIF at 760 nm in temperate deciduous forests. SIF correlated with GPP estimated with eddy covariance at diurnal and seasonal scales (r2 = 0.82 and 0.73, respectively), as well as with APAR diurnally and seasonally (r2 = 0.90 and 0.80, respectively). SIF/APAR is significantly positively correlated with LUE and is higher during cloudy days than sunny days. Weekly tower-based SIF agreed with SIF from the Global Ozone Monitoring Experiment-2 (r2 = 0.82). Our results provide ground-based evidence that SIF is directly related to both APAR and LUE and thus GPP, and confirm that satellite SIF can be used as a proxy for GPP.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    Ramin; Lotfi; Mohammad; Pessarakli; Puriya; Gharavi-Kouchebagh; Hossein; Khoshvaghti

    2015-01-01

    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 Foto Fmand 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.

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

    Institute of Scientific and Technical Information of China (English)

    Ramin Lotfi; Mohammad Pessarakli; Puriya Gharavi-Kouchebagh; Hossein Khoshvaghti

    2015-01-01

    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.

  4. Effects of NaCl Stress on Chlorophyll Fluorescence Parameters in Cinnamomum japonicum var. chenii%NaCl胁迫对普陀樟叶绿素荧光参数的影响

    Institute of Scientific and Technical Information of China (English)

    李影丽; 汪奎宏; 杜国坚; 许利群; 杨华; 肖纪军

    2008-01-01

    [Objective] Study on the changes of chlorophyll fluorescence parameters in Cinnamomum japonicum var. chenii under NaCl stress. [Method] The seedling growth increment, chlorophyll content and chlorophyll fluorescence parameters in leaves of 1-year old Cinnamomum japonicum var. chenii were investigated in field experiment. [Result] Under NaCl stress, seedling growth increment reduced and the chlorophyll content decreased to a stable value; changes of Fv/Fm and Fv/Fo showed identical increasing trend and double peak type. With the aggravation of salt stress, most variations were ob- served in Fo, correlations among chlorophyll fluorescence parameters presented "rise-drop" trend (in the treatment of 7 g/L NaCl). [Condusion] Cinna-momum japonicum var. chenii is endowed with strong salt resistance and wide adaptability.

  5. Observation of silicon-mediated alleviation of cadmium stress in maize (Zea mays L.) seedlings via LED-induced chlorophyll fluorescence

    Science.gov (United States)

    Gouveia-Neto, Artur S.; Silva, Elias A.; da Silva, Airon José; do Nascimento, Clístenes W. A.

    2013-02-01

    LED-induced chlorophyll fluorescence analysis is exploited to observe, and monitor the time evolution of silicon-induced alleviation of toxicity in maize (Zea mays L.) seedlings in cadmium contaminated soil. Red, and far-red emissions were examined as a function of cadmium-silicon concentrations, during the 20 days period of the seedlings growing process under stress. The chlorophyll fluorescence spectral analysis provided detection, and evaluation of the damage imposed by the metal stress in the early stages of the plant growing process. The technique also provided the time evolution evaluation of the silicon-induced tolerance enhancement of maize plants to cadmium, which is not viable using conventional in vitro spectral analysis techniques

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

    OpenAIRE

    Siheng Wang; Changping Huang; Lifu Zhang; Yi Lin; Yi Cen; Taixia Wu

    2016-01-01

    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 ...

  7. Effect of modified montmorillonite and polyacrylamide on growth parameters and chlorophyll fluorescence of corn in Cd- and Pb-polluted soils

    OpenAIRE

    Hosseini, H; H. Shirani; M. Hamidpour; Shamshiri, H; H. Dashti; R. Ranjbar-Karimi

    2012-01-01

    Heavy metals decrease plant growth due to disorder in enzyme activities and destroying of protein structure. Since corn is an important crop in human and poultry nutrition, in this greenhouse experiment, the effect of modified polyacrylamide and montmorillonite on growth parameters and chlorophyll fluorescence of corn (Zea mays L.) grown in two polluted soils with Cd and Pb (sandy and sandy loam) was investigated. This experiment was performed using completely randomized design with four repl...

  8. 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. PMID:16666615

  9. Latent manganese deficiency in barley can be diagnosed and remediated on the basis of chlorophyll a fluorescence measurements

    DEFF Research Database (Denmark)

    Schmidt, Sidsel Birkelund; Pedas, Pai; Laursen, Kristian Holst;

    2013-01-01

    Background and aims: Manganese (Mn) deficiency represents a major plant nutritional disorder in winter cereals. The deficiency frequently occurs latently and the lack of visual symptoms prevents timely remediation and cause significant yield reductions. These problems prompted us to investigate....... Chlorophyll a fluorescence measurements constitute a powerful and valuable tool for diagnosis and remediation of latent Mn deficiency. © 2013 Springer Science+Business Media Dordrecht....

  10. Effects of different concentrations of nitrogen and phosphorus on chlorophyll biosynthesis,chlorophyll a fluorescence,and photosynthesis In Larix olgensis seedlings

    Institute of Scientific and Technical Information of China (English)

    Wu Chu; Wang Zhengquan; Sun Hailong; Guo Shenglei

    2006-01-01

    In our experiments,one-year-old Larix olgensis seedlings were cultivated in sand,and supplied with solutions with different concentrations of nitrate or phosphate.The effects of nitrogen and phosphorus supply on chlorophyll biosynthesis,total nitrogen content,and photosynthetic rate were studied.The experimental results are listed below: 1) 5-aminolevulinic acid (ALA) synthetic rate increased as nitrate concentrations supplied to larch seedlings increased from 1 to 8 mmol/L.But the rate decreased by 17% when nitrate concentration increased to 16 mmol/L,in contrast to the control.Under phosphate treatments,ALA synthetic rates were similar to those under nitrate treatments.The activities of porphobilinogen (PBG)synthase reached a maximum when larch seedlings were supplied with 8 mmol/L of nitrate or 1 mmol/L of phosphate.2) When larch seedlings were supplied with 8 mmol/L of nitrate and 0.5 mmol/L of phosphate,the contents of chlorophyll a,chlorophyll b,total chlorophyll,and carotenoids reached a maximum.The total nitrogen contents in leaves increased as nitrate concentrations increased.3) When phosphate concentrations increased from 0.125 to 1 mmol/L,the total nitrogen contents in leaves slightly increased;however,continuous increase of phosphate concentrations resulted in the decrease in total nitrogen contents in leaves.When nitrate concentrations increased from 1 to 8 mmol/L,soluble protein contents in leaves increased in general,and continuous increase of nitrate concentrations induced a decrease in soluble protein contents in leaves.Under treatment of 0.25 mmol/L of phosphate,the soluble protein contents reached a maximum.4) In general,Fv/Fm increased as nitrate concentrations increased from 1 to 8 mmol/L,and continuous increase of nitrate concentration resulted in decrease in FvlFm.The similar changes occurred under phosphate treatments.As nitrate concentrations increased from 1 to 8 mmol/L,photosynthetic rates gradually increased,but when nitrate

  11. Ratiometric fluorescence signalling of fluoride ions by an amidophthalimide derivative

    Indian Academy of Sciences (India)

    Moloy Sarkar; Raghavendra Yellampalli; Bhaswati Bhattacharya; Ravi Kumar Kanaparthi; Anunay Samanta

    2007-03-01

    Fluorescence behaviour of 4-benzoylamido-N-methylphthalimide (1), designed and developed for selective detection of fluoride ions, is reported. 1 displays F--induced colour change that allows its detection with the naked eye. The F- specificity of the sensor system is evident from the fact that unlike F-, other halides do not affect the absorption characteristics of 1. Apart from the colorimetric response, the fluorescence output of 1 is also modulated by F- in a manner that permits ratiometric fluorescence signalling of F- as well. It is found that the system can detect F- in the concentration range of 10- 60 M. The results of the experiments and theoretical calculations unambiguously suggest that the changes of the electronic absorption and fluorescence behaviour of 1, which have been exploited for signalling purpose, are due to F--induced deprotonation of the 4-amido moiety of the sensor system.

  12. Upward and downward solar-induced chlorophyll fluorescence yield indices of four tree species as indicators of traffic pollution in Valencia

    International Nuclear Information System (INIS)

    Passive steady-state chlorophyll fluorescence (Fs) provides a direct diagnosis of the functional status of vegetation photosynthesis. With the prospect of mapping Fs using remote sensing techniques, field measurements are mandatory to understand to which extent Fs allows detecting plant stress in different environments. Trees of four common species in Valencia were classified in either a low or a high local traffic exposure class based on their leaf magnetic value. Upward and downward hyperspectral fluorescence yield (FY) and indices based on the two Fs peaks (at 687 and 741 nm) were calculated. FY indices of P. canariensis and P. x acerifolia were significantly different between the two traffic exposure classes defined, but not for C. australis nor M. alba. While chlorophyll content could not indicate the difference between low and high traffic exposure, the FY(687)/FY(741) peak ratio increased significantly (p < 0.05) for both leaf sides for the higher traffic exposure class. - Highlights: ► Potential of fluorescence yield parameters as stress detectors for traffic pollution. ► SIRM functions as a measure for local traffic emissions at tree level. ► Some urban trees show a fluorescence yield response to increased traffic exposure. ► Fs is a more sensitive indicator of (traffic) pollution stress than Chl content as such. - Fluorescence yield parameters as stress detectors for traffic-exposed urban trees are tested.

  13. The development of attenuation compensation models of fluorescence spectroscopy signals

    Science.gov (United States)

    Dremin, Victor V.; Zherebtsov, Evgeny A.; Rafailov, Ilya E.; Vinokurov, Andrey Y.; Novikova, Irina N.; Zherebtsova, Angelina I.; Litvinova, Karina S.; Dunaev, Andrey V.

    2016-04-01

    This study examines the effect of blood absorption on the endogenous fluorescence signal intensity of biological tissues. Experimental studies were conducted to identify these effects. To register the fluorescence intensity, the fluorescence spectroscopy method was employed. The intensity of the blood flow was measured by laser Doppler flowmetry. We proposed one possible implementation of the Monte Carlo method for the theoretical analysis of the effect of blood on the fluorescence signals. The simulation is constructed as a four-layer skin optical model based on the known optical parameters of the skin with different levels of blood supply. With the help of the simulation, we demonstrate how the level of blood supply can affect the appearance of the fluorescence spectra. In addition, to describe the properties of biological tissue, which may affect the fluorescence spectra, we turned to the method of diffuse reflectance spectroscopy (DRS). Using the spectral data provided by the DRS, the tissue attenuation effect can be extracted and used to correct the fluorescence spectra.

  14. FluorMODgui V3.0: A graphic user interface for the spectral simulation of leaf and canopy chlorophyll fluorescence

    Science.gov (United States)

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

    2006-06-01

    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 the measurement of solar-induced chlorophyll fluorescence using remote-sensing instruments require physical methods for quantitative feasibility analysis and sensor specification studies. The FluorMODgui model developed as part of this project is designed to simulate the effects of chlorophyll fluorescence at leaf and canopy levels using atmospheric inputs, running the leaf model, FluorMODleaf, and the canopy model, FluorSAIL, independently, through a coupling scheme, and by a multiple iteration protocol to simulate changes in the viewing geometry and atmospheric characteristics. Inputs for the FluorMODleaf model are the number of leaf layers, chlorophyll a+ b content, water equivalent thickness, dry matter content, fluorescence quantum efficiency, temperature, species type, and stoichiometry. Inputs for the FluorSAIL canopy model are a MODTRAN-4 6-parameter spectra or measured direct horizontal irradiance and diffuse irradiance spectra, a soil reflectance spectrum, leaf reflectance & transmittance spectra and a excitation-fluorescence response matrix in upward and downward directions (all from FluorMODleaf), 2 PAR-dependent coefficients for the fluorescence response to light level, relative azimuth angle and viewing zenith angle, canopy leaf area index, leaf inclination distribution function, and a hot spot parameter. Outputs available in the 400-1000 nm spectral range from the graphical user interface, FluorMODgui, are the leaf spectral reflectance and transmittance, and the

  15. Chlorophyll fluorescence induction kinetics and yield responses in rainfed crops with variable potassium nutrition in K deficient semi-arid alfisols.

    Science.gov (United States)

    Srinivasarao, Ch; Shanker, Arun K; Kundu, Sumanta; Reddy, Sharanbhoopal

    2016-07-01

    Optimum potassium (K) nutrition in semi-arid regions may help crop plants to overcome constraints in their growth and development such as moisture stress, leading to higher productivity of rainfed crops, thus judicious K management is essential. A study was conducted to evaluate the importance of K nutrition on physiological processes like photosynthesis through chlorophyll a fluorescence and chlorophyll fluorescence induction kinetics (OJIP) of rainfed crops viz., maize (Zea mays L.), pearl millet (Pennisetum glaucum), groundnut (Arachis hypogaea), sunflower (Helianthus annuus), castor (Ricinus communis L.) and cotton (Gossypium hirsutum) under water stress conditions by studying their growth attributes, water relations, yield, K uptake and use efficiency under varied K levels. Highest chlorophyll content was observed under K60 in maize and pearl millet. Narrow and wide Chl a:b ratio was observed in castor and groundnut respectively. The fluorescence yield decreased in the crops as K dosage increased, evidenced by increasing of all points (O, J, I and P) of the OJIP curves. The fluorescence transient curve for K60 was lower than K0 and K40 for all the crops. Potassium levels altered the fluorescence induction and impaired photosynthetic systems in all the crops studied. There was no distinct trend observed in leaf water potential of crops under study. Uptake of K was high in sunflower with increased rate of K application. Quantitatively, K uptake by castor crop was lesser compared to all other crops. Our results indicate that the yield reduction under low K was due to the low capacity of the crops to translocate K from non-photosynthetic organs such as stems and petioles to upper leaves and harvested organs and this in turn influenced the capacity of the crops to produce a high economic yield per unit of K taken up thus reducing utilization efficiency of K. PMID:27101276

  16. 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. PMID:26423334

  17. Sun-induced chlorophyll fluorescence reveals strong representation of photosynthesis at ecosystem level in rice paddy field in Japan

    Science.gov (United States)

    Kato, T.; Tsujimoto, K.; Nasahara, K. N.; Akitsu, T.; Ono, K.; Miyata, A.

    2015-12-01

    Chlorophyll fluorescence emission from ecosystem induced by sunlight (Sun-Induced Fluorescence: SIF) is now a key factor to accurately estimate the ecosystem-level photosynthesis activity as suggested by satellite studies, and has been recently detected by satellites [Frankenberg et al., 2011; Guanter et al., 2012; Joiner et al., 2013] and measured at field stations [Daumard et al., 2010; Porcar-Castell, 2011]. However, the few example of field-based assessment on the representation ability reduces its value for the availability to better understand the dynamics in CO2uptake by land ecosystem. To elucidate the potential of SIF to estimate ecosystem GPP in typical Asian crop type, the canopy-top SIF was calculated from the spectrum data in Japanese rice paddy field in Mase in central Japan (36°03'N, 140°01'E, 11 m a.s.l.), and compared with eddy-tower measured GPP on half-hourly and daily bases during seven years from 2006 to 2012. The rice (Oriza sativa L.; cultivar Koshihikari) was transplanted in May and harvested in September normally. The SIF was estimated from the spectrums of downward Sun irradiance and upward canopy-reflected radiance measured at the height of 3m above ground by HemiSpherical Spectro-Radiometer (HSSR), consisting of the spectroradiometer (MS-700, Eko inc., Tokyo, Japan) with the full-width at half maximum (FWHM) of 10 nm and wavelength interval of 3.3 nm. The SIF around 760nm (O2-A band: Fs760) was calculated according to the Fraunhofer Line Depth principle [Maier et al., 2003] with several additional arrangements. The GPP increased almost linearly as both Fs760 and APAR (Absorbed Photosyntethically Active Radiation) increased based on monthly-averaged diurnal courses during the growing season in 2006. The slopes of their regression lines differed much among the months in APAR, but in Fs760. These nearly constant relationships among the months between GPP and Fs760 were kept for all the observation years. Daily averaged GPP and Fs760

  18. Mg chelatase in chlorophyll synthesis and retrograde signaling in Chlamydomonas reinhardtii: CHLI2 cannot substitute for CHLI1.

    Science.gov (United States)

    Brzezowski, Pawel; Sharifi, Marina N; Dent, Rachel M; Morhard, Marius K; Niyogi, Krishna K; Grimm, Bernhard

    2016-06-01

    The oligomeric Mg chelatase (MgCh), consisting of the subunits CHLH, CHLI, and CHLD, is located at the central site of chlorophyll synthesis, but is also thought to have an additional function in regulatory feedback control of the tetrapyrrole biosynthesis pathway and in chloroplast retrograde signaling. In Arabidopsis thaliana and Chlamydomonas reinhardtii, two genes have been proposed to encode the CHLI subunit of MgCh. While the role of CHLI1 in A. thaliana MgCh has been substantially elucidated, different reports provide inconsistent results with regard to the function of CHLI2 in Mg chelation and retrograde signaling. In the present report, the possible functions of both isoforms were analyzed in C. reinhardtii Knockout of the CHLI1 gene resulted in complete loss of MgCh activity, absence of chlorophyll, acute light sensitivity, and, as a consequence, down-regulation of tetrapyrrole biosynthesis and photosynthesis-associated nuclear genes. These observations indicate a phenotypical resemblance of chli1 to the chlh and chld C. reinhardtii mutants previously reported. The key role of CHLI1 for MgCh reaction in comparison with the second isoform was confirmed by the rescue of chli1 with genomic CHLI1 Because CHLI2 in C. reinhardtii shows lower expression than CHLI1, strains overexpressing CHLI2 were produced in the chli1 background. However, no complementation of the chli1 phenotype was observed. Silencing of CHLI2 in the wild-type background did not result in any changes in the accumulation of tetrapyrrole intermediates or of chlorophyll. The results suggest that, unlike in A. thaliana, changes in CHLI2 content observed in the present studies do not affect formation and activity of MgCh in C. reinhardtii. PMID:26809558

  19. Correlation signals in resonance fluorescence : interpretation via photon scattering amplitudes

    OpenAIRE

    Dalibard, J.; Reynaud, S.

    1983-01-01

    Resonance fluorescence is treated as a collision process where incident laser photons are scattered by an atom. Correlation signals are extracted from an expansion to the second order of the post collision field state. Photon antibunching effect appears as a quantum interference between all the possible scattering amplitudes. When Rayleigh photons are rejected, some amplitudes vanish, leading to a bunching behaviour.

  20. 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

  1. The fluorescence of chlorophyll and yellow substances in natural waters: A note on the problems of measurement and the importance of their remote sensing

    Science.gov (United States)

    Yentsch, C. S.

    1975-01-01

    There are two chromophylls which, if sensed remotely from high altitude, would revolutionize the ability to survey large areas of the world's oceans. The chromophylls of importance are: the photosynthetic pigments of plankton algae and a group of organic materials frequently termed dissolved yellow substances. These are derived from plants and carried into the ocean by fresh water inflow. The attenuation of light by phytoplankton is characterized by two distinctive bands (450, 675 nm) which represent absorption by chloroplastic pigments. Yellow substances are characterized by a strong ultraviolet absorption which tails over into the visible region. It is emphasized that chlorophyll determination could be a unique technique for estimating the extent of eutrophication in coastal waters, and that a high altitude observer equipped with temperature, chlorophyll and yellow substance sensors has the possibility of detecting the magnitude of eutrophication and its sources by using laser induced fluorescent devices.

  2. SIGNALS REGARDING THE ISOLATION OF CHLOROPHYL-FREE ALGAE IN THE MILK OF SOME HEALTHY COWS AND SOME WITH MAMITTIS

    Directory of Open Access Journals (Sweden)

    Laurent OGNEAN

    2002-03-01

    Full Text Available In the microbiological investigation, made on samples of normal; (n=412 and mastitic (n=482 milk, proceeded from eight dairy cows farm, in Transilvania, it was signal the presence of the algae without chlorophyl belonging to Prototheca, forming together with bacteria and fungi the micro flora of the mammary gland. The alga content of normal milk was signaled only in two farms (2.27%, respectively 1.21%, being established to 0.72%. In the case of mastitic milk the percentage of positive samples raised up to 3.3%, the isolating frequency being important only in one farm (9.6%, where were episodes of antibiotic resistant mastitis. The alga were well developed on gelose and Sabouraud agar, at 20-37°C, and their identification as Prototheca, was based on making evident the typical morphological elements, big sporangium (10-30μm containing 4-8 daughter cells.

  3. Red fluorescence in reef fish: A novel signalling mechanism?

    Directory of Open Access Journals (Sweden)

    Siebeck Ulrike E

    2008-09-01

    Full Text Available Abstract Background At depths below 10 m, reefs are dominated by blue-green light because seawater selectively absorbs the longer, 'red' wavelengths beyond 600 nm from the downwelling sunlight. Consequently, the visual pigments of many reef fish are matched to shorter wavelengths, which are transmitted better by water. Combining the typically poor long-wavelength sensitivity of fish eyes with the presumed lack of ambient red light, red light is currently considered irrelevant for reef fish. However, previous studies ignore the fact that several marine organisms, including deep sea fish, produce their own red luminescence and are capable of seeing it. Results We here report that at least 32 reef fishes from 16 genera and 5 families show pronounced red fluorescence under natural, daytime conditions at depths where downwelling red light is virtually absent. Fluorescence was confirmed by extensive spectrometry in the laboratory. In most cases peak emission was around 600 nm and fluorescence was associated with guanine crystals, which thus far were known for their light reflecting properties only. Our data indicate that red fluorescence may function in a context of intraspecific communication. Fluorescence patterns were typically associated with the eyes or the head, varying substantially even between species of the same genus. Moreover red fluorescence was particularly strong in fins that are involved in intraspecific signalling. Finally, microspectrometry in one fluorescent goby, Eviota pellucida, showed a long-wave sensitivity that overlapped with its own red fluorescence, indicating that this species is capable of seeing its own fluorescence. Conclusion We show that red fluorescence is widespread among marine fishes. Many features indicate that it is used as a private communication mechanism in small, benthic, pair- or group-living fishes. Many of these species show quite cryptic colouration in other parts of the visible spectrum. High inter

  4. O2 exchange and chlorophyll fluorescent measurements in Australian native grasses: a comparison on NADP-ME and NAD-ME C4 subtypes

    International Nuclear Information System (INIS)

    Full text: C4 grasses dominate the vegetation of Australia's tropical and arid grasslands. They have very diverse origins; however biochemically, they fall into three main types: NAD-ME, PCK and NADP-ME. The most notable differences among these subtypes are the contrasting leaf dry matter δ13C and geographic distribution according to rainfall. Our long-term aim is to understand the physiological significance of the biochemical diversification of C4 photosynthesis in grasses. Here we have investigated the O2 exchange and fluorescence characteristics in NADP-ME (C. ciliaris, B. bladhii, P. antidotale, P. alopecuroides) and NAD-ME (A. Iappacea, E. superba, L. dubia, P. coloratum) grasses. The plants were 3.5 to 5 weeks old and grown under well-watered conditions in a growth cabinet with 10/5/4/5 h of 0/400/700/400 μmol m-2 S-1 PAR. Mass spectrometric measurements of 16O2 and 18O2 exchange were made concurrently with measurements of chlorophyll fluorescence on leaf discs in a closed leaf chamber. There was a good correlation between electron transport rates estimated from chlorophyll fluorescence and 16O2 measurements (within 10%) at high light and high CO2 concentrations. At low light estimates from chlorophyll fluorescence were 15 to 20% greater than estimates obtained form 16O2 evolution. Maximal electron transport rates at saturating CO2 were similar between the two C4 subtypes at all irradiances. However, both chlorophyll fluorescence and measurements of 16O2 evolution, revealed that NAD-ME species had significantly greater electron transport rates at the CO2-compensation point than the NADP-ME species1'8O2 uptake at saturating CO2 increased with increasing irradiance and was approximately 20% of 16O2 evolution at all irradiances and for both C4 subtypes. It was approximately 3.5 times greater than dark 18O-2 uptake indicating a significant amount of O2 uptake was associated with the Mehler reaction. The observed differences between NAD and NADP ME grasses will

  5. Chlorophyll fluorescence of tropical tree species in a semi-deciduous forest gap Fluorescência da clorofila de espécies arbóreas tropicais em uma clareira de floresta semidecídua

    OpenAIRE

    Rafael Vasconcelos Ribeiro; Gustavo Maia Souza; Angelo Gilberto Manzatto; Eduardo Caruso Machado; Ricardo Ferraz de Oliveira

    2004-01-01

    The characterization of different ecological groups in a forest formation/succession is unclear. To better define the different successional classes, we have to consider ecophysiological aspects, such as the capacity to use or dissipate the light energy available. The main objective of this work was to assess the chlorophyll fluorescence emission of tropical tree species growing in a gap of a semi-deciduous forest. Three species of different ecological groups were selected: Croton floribundus...

  6. Comparison of solar-induced chlorophyll fluorescence, light-use efficiency, and process-based GPP models in maize.

    Science.gov (United States)

    Wagle, Pradeep; Zhang, Yongguang; Jin, Cui; Xiao, Xiangming

    2016-06-01

    Accurately quantifying cropland gross primary production (GPP) is of great importance to monitor cropland status and carbon budgets. Satellite-based light-use efficiency (LUE) models and process-based terrestrial biosphere models (TBMs) have been widely used to quantify cropland GPP at different scales in past decades. However, model estimates of GPP are still subject to large uncertainties, especially for croplands. More recently, space-borne solar-induced chlorophyll fluorescence (SIF) has shown the ability to monitor photosynthesis from space, providing new insights into actual photosynthesis monitoring. In this study, we examined the potential of SIF data to describe maize phenology and evaluated three GPP modeling approaches (space-borne SIF retrievals, a LUE-based vegetation photosynthesis model [VPM], and a process-based soil canopy observation of photochemistry and energy flux [SCOPE] model constrained by SIF) at a maize (Zea mays L.) site in Mead, Nebraska, USA. The result shows that SIF captured the seasonal variations (particularly during the early and late growing season) of tower-derived GPP (GPP_EC) much better than did satellite-based vegetation indices (enhanced vegetation index [EVI] and land surface water index [LSWI]). Consequently, SIF was strongly correlated with GPP_EC than were EVI and LSWI. Evaluation of GPP estimates against GPP_EC during the growing season demonstrated that all three modeling approaches provided reasonable estimates of maize GPP, with Pearson's correlation coefficients (r) of 0.97, 0.94, and 0.93 for the SCOPE, VPM, and SIF models, respectively. The SCOPE model provided the best simulation of maize GPP when SIF observations were incorporated through optimizing the key parameter of maximum carboxylation capacity (Vcmax). Our results illustrate the potential of SIF data to offer an additional way to investigate the seasonality of photosynthetic activity, to constrain process-based models for improving GPP estimates, and to

  7. 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.

  8. Evaluation the vigour of urban green lawn grown under long-term shade conditions by the use of chlorophyll fluorescence technique

    Directory of Open Access Journals (Sweden)

    Dąbrowski Piotr

    2015-09-01

    Full Text Available Unfavorable light conditions in urban areas are one of the most important cause of inappropriate grass communities condition. The possibility to detect the plant stress caused by shade is an important element in shaping the environment. The answer to following questions: what is the ability to detect the stress caused by shade in chosen lawn varieties of Perennial ryegrass by using the chlorophyll a fluorescence (O-J-I-P test and which of tested varieties has the best properties to create grasslands in reduced light conditions is the aim of this work. Two-factor experimental micro-plot was conducted with three varieties and three different shadowing variants. Chlorophyll a fluorescence measurements were provided and were compared to leaf density. Our results explored significant difference between selected varieties in the terms of their photosynthetic apparatus adaption to light conditions. During May, all tested varieties were characterized by the rise of all fluorescence curve points under lower light intensity. The largest changes under shade conditions were noticed for the variety ‘Taya’. During next months a declining trend of photosynthetic efficiency for this variety was observed. On the basis of our results, we assume that each variety has unique threshold and needs of light intensity.

  9. Effect of Different Norms of Under-Mulch-Drip Irrigation on Diurnal Changes of Photosynthesis and Chlorophyll Fluorescence Parameter in High Yield Cotton of Xinjiang

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wang-feng; REN Li-tong; WANG Zhen-lin; LI Shao-kun; GOU Ling; YU Songlie; CAO Lian-pu

    2003-01-01

    Under-mulch-drip irrigation is an advanced irrigation technique, which combines plastic-film-covered cultivation with drip irrigation. The influence of different norms of under-mulch-drip irrigation on di-urnal changes of photosynthetic rates and chlorophyll fluorescence parameters of cotton was studied, in orderto understand the physiological mechanisms of water-saving and high-yielding farming in Xinjiang. Results in-dicated that limited drip irrigation, which supplies 2/3 of 375 m3 ha-1 , the widely-used irrigation norm in cot-ton cultivation in Xinjiang, caused a water deficit in cotton field. Compared with the proper drip irrigation,the leaf photosynthetic rate under limited drip irrigation decreased during 9:00 to 11:00 a. m., and was sig-nificantly suppressed at midday, and then recovered afterwards. Using the chlorophyll fluorescence method,the absorption, transfer and transformation features of solar radiation by cotton leaf were investigated. Underlimited drip irrigation, the variable fluorescence (Fy) and primary light transfer efficiency of PSII (Fv/Fm)in cotton leaves were reduced because of the high light intensities and high temperatures at noon, and the de-crease in Xinluzao8 was greater than that in Xinluzao6. Therefore, it could be concluded that Xinluzao6 has ahigher drought-tolerance, and the Fv/Fm ratio could be used as a drought-resistance index for cotton.

  10. Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon FluxMeasurements ofMontanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone

    Czech Academy of Sciences Publication Activity Database

    Ač, Alexander; Malenovský, Z.; Urban, Otmar; Hanuš, Jan; Zitová, Martina; Navrátil, M.; Vráblová, M.; Olejníčková, Julie; Špunda, V.; Marek, Michal V.

    2012-01-01

    Roč. 2012, č. 2012 (2012), s. 1-13. ISSN 1537-744X R&D Projects: GA MŽP(CZ) SP/2D1/70/08; GA MŽP(CZ) SP/2D1/93/07; GA MŠk(CZ) LM2010007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional research plan: CEZ:AV0Z60870520 Keywords : Chlorophyll fluorescence * carbon flux * forest ecosystems * Norway Spruce * temperate zone Subject RIV: EH - Ecology, Behaviour Impact factor: 1.730, year: 2012

  11. Effect of photosystem I inactivation on chlorophyll a fluorescence induction in wheat leaves: Does activity of photosystem I play any role in OJIP rise?

    Science.gov (United States)

    Zivcak, Marek; Brestic, Marian; Kunderlikova, Kristyna; Olsovska, Katarina; Allakhverdiev, Suleyman I

    2015-11-01

    Interpretation of the fast chlorophyll a fluorescence induction is still a subject of continuing discussion. One of the contentious issues is the influence of photosystem I (PSI) activity on the kinetics of the thermal JIP-phase of OJIP rise. To demonstrate this influence, we realized a series of measurements in wheat leaves subjected to PSI photoinactivation by the sequence of red saturation pulses (15,000 μmol photons m(-2) s(-1) for 0.3 s, every 10 s) applied in darkness. Such a treatment led to a moderate decrease of maximum quantum efficiency of PSII (by ~8%), but a strong decrease of the number of oxidizable PSI (by ~55%), which considerably limited linear electron transport and CO2 assimilation. Surprisingly, the PSI photoinactivation had low effects on OJIP kinetics of variable fluorescence. In particular, the amplitude of variable fluorescence of IP-step (ΔVIP), which has been considered to be a measure of PSI content, was not decreased, despite the low content of photooxidizable PSI. On the other hand, the slower relaxation of chlorophyll fluorescence after saturation pulse as well as the results of the double-hit method suggest that PSI inactivation treatment led to an increase of the fraction of QB-nonreducing PSII reaction centers. Our results somewhat challenge the mainstream interpretations of JIP-thermal phase, and at least suggest that the IP amplitude cannot serve to estimate reliably the PSI content or the PSI to PSII ratio. Moreover, these results recommend the use of the novel method of PSI inactivation, which might help clarify some important issues needed for the correct understanding of the OJIP fluorescence rise. PMID:26388470

  12. Airborne simultaneous spectroscopic detection of laser-induced water Raman backscatter and fluorescence from chlorophyll a and other naturally occurring pigments

    Science.gov (United States)

    Hoge, F. E.; Swift, R. N.

    1981-01-01

    The airborne laser-induced spectral emission bands obtained simultaneously from water Raman backscatter and the fluorescence of chlorophyll and other naturally occurring waterborne pigments are reported here for the first time. The importance of this type data lies not only in its single-shot multispectral character but also in the application of the Raman line for correction or calibration of the spatial variation of the laser penetration depth without the need for in situ water attenuation measurements. The entire laser-induced fluorescence and Raman scatter emissions resulting from each separate 532-nm 10-nsec laser pulse are collected and spectrally dispersed in a diffraction grating spectrometer having forty photomultiplier tube detectors. Results from field experiments conducted in the North Sea and the Chesapeake Bay/Potomac River are presented. Difficulties involving the multispectral resolution of the induced emissions are addressed, and feasible solutions are suggested together with new instrument configurations and future research directions.

  13. 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

    Modern highly insulated greenhouses are more energy efficient than conventional types. Furthermore applying dynamic greenhouse climate control regimes will increase energy efficiency relatively more in modern structures. However, this combination may result in higher air and crop temperatures. Too...... mol−1 and with a photosynthetic photon flux density (PPFD) of 800 μmol m−2 s−1, net photosynthesis (Pn) reached its maximum at 35 °C. The thermal index (IG), calculated from the leaf temperature and the temperature of a dry and wet reference leaf, showed a strong correlation with gs. We conclude...... that 1) chlorophyll a fluorescence and a combination of fluorescence parameters can be used as early stress indicators as well as to detect the temperature limit of PSII damage, and 2) the strong relation between gs and IG enables gs to be estimated non-invasively, which is an important first step...

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

    International Nuclear Information System (INIS)

    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. - Highlights: • Ozone (O3) concentrations recorded were within the ranges of phytotoxicity. • O3 has a clear influence on the physiological parameters. • O3 decreased Photosynthetic rates, chlorophyll fluorescence parameters. • The

  15. Small-scale variability of chlorophyll, CDOM, and suspended matter in the Lake Balaton as obtained by shipborne UV fluorescent lidar

    Science.gov (United States)

    Pelevin, Vadim; Palmer, Stephanie; Khymchenko, Lisa

    2015-04-01

    Despite a long history in oceanography, few attempts have been made to use fluorescent lidars to evaluate water quality in lakes. We report lidar measurements taken on the Lake Balaton over the period of five days in August, 2012. Lake Balaton, the largest lake in Central Europe in area (597 km2), is very shallow (average depth of 3.5m). The lake is mesotrophic exhibiting a strong trophic gradient from SW to NE. The UV fluorescent lidar UFL-9 used in this study was developed at the Shirshov Institute of Oceanology. It can be used for CDOM, organic pollutants, chlorophyll, and suspended matter concentrations measurements at very high spatial resolution (up to ~1 m). The data were collected continuously during daytime while the boat was travelling. The entire area of the lake was covered by the measurement. The lidar data were calibrated against those obtained in situ through water sampling and then converted from the optical units into the mass concentrations of the above mentioned constituents. Based on this data set, we mapped and investigated in detail the small-scale spatial variability of CDOM, chlorophyll-a, and suspended matter concentrations. In particular, the characteristics of patchiness for the selected parameters were quantified and inter-compared, and their relations with the background forcing conditions were analyzed. We also discuss the applicability of lidar techniques for assessing the hydrological and ecological conditions in shallow inland water bodies. The study was partly supported by the Russian Science Foundation, Grant 14-50-00095.

  16. Effects of Chilling Stress on Photosynthetic Rate and Chlorophyll Fluorescence Parameter in Seedlings of Two Rice Cultivars Differing in Cold Tolerance

    Institute of Scientific and Technical Information of China (English)

    WANG Guo-li; GUO Zhen-fei

    2005-01-01

    A cold-tolerant cultivar, Xiangnuo 1, and a cold-sensitive cultivar, IR50, were used to study the influence of chilling on photosynthetic rate and chlorophyll fluorescence parameters in rice seedlings. The photosynthetic rates declined dramatically during chilling, and decreased by 48.7% and 67.5% in Xiangnuo 1 and IR50 seedlings, respectively, after being subjected to chilling treatment for two days. Chlorophyll fluorescence measurements showed that relatively higher qP and qNP in Xiangnuo 1 were maintained to dissipate the redundant excitation energy and protect the reaction centers from chill injury; accordingly, redundant excitation energy accumulated less in the reaction centers, and antenna systems were less injured by chilling in Xiangnuo 1. On the contrary, in IR50, qP and qNP declined rapidly while Ex increased, as the chilling persisted. This result indicated that the reaction centers and antenna systems in IR50 were damaged severely by chilling, which led to the lower photosynthetic rate.

  17. Signal enhanced holographic fluorescence microscopy with guide-star reconstruction

    Science.gov (United States)

    Jang, Changwon; Clark, David C.; Kim, Jonghyun; Lee, Byoungho; Kim, Myung K.

    2016-01-01

    We propose a signal enhanced guide-star reconstruction method for holographic fluorescence microscopy. In the late 00’s, incoherent digital holography started to be vigorously studied by several groups to overcome the limitations of conventional digital holography. The basic concept of incoherent digital holography is to acquire the complex hologram from incoherent light by utilizing temporal coherency of a spatially incoherent light source. The advent of incoherent digital holography opened new possibility of holographic fluorescence microscopy (HFM), which was difficult to achieve with conventional digital holography. However there has been an important issue of low and noisy signal in HFM which slows down the system speed and degrades the imaging quality. When guide-star reconstruction is adopted, the image reconstruction gives an improved result compared to the conventional propagation reconstruction method. The guide-star reconstruction method gives higher imaging signal-to-noise ratio since the acquired complex point spread function provides optimal system-adaptive information and can restore the signal buried in the noise more efficiently. We present theoretical explanation and simulation as well as experimental results.

  18. 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. PMID:27556995

  19. Comparison of Measurements and FluorMOD Simulations for Solar Induced Chlorophyll Fluorescence and Reflectance of a Corn Crop under Nitrogen Treatments [SIF and Reflectance for Corn

    Science.gov (United States)

    Middleton, Elizabeth M.; Corp, Lawrence A.; Campbell, Petya K. E.

    2007-01-01

    The FLuorescence Explorer (FLEX) satellite concept is one of six semifinalist mission proposals selected in 2006 for pre-Phase studies by the European Space Agency (ESA). The FLEX concept proposes to measure passive solar induced chlorophyll fluorescence (SIF) of terrestrial ecosystems. A new spectral vegetation Fluorescence Model (FluorMOD) was developed to include the effects of steady state SIF on canopy reflectance. We used our laboratory and field measurements previously acquired from foliage and canopies of corn (Zea mays L.) under controlled nitrogen (N) fertilization to parameterize and evaluate FluorMOD. Our data included biophysical properties, fluorescence (F) and reflectance spectra for leaves; reflectance spectra of canopies and soil; solar irradiance; plot-level leaf area index; and canopy SIF emissions determined using the Fraunhofer Line Depth principal for the atmospheric telluric oxygen absorption features at 688 nm (O2-beta) and 760 nm (O2-alpha). FluorMOD simulations implemented in the default "look-up-table" mode did not reproduce the observed magnitudes of leaf F, canopy SIF, or canopy reflectance. However, simulations for all of these parameters agreed with observations when the default FluorMOD information was replaced with measurements, although N treatment responses were underestimated. Recommendations were provided to enhance FluorMOD's potential utility in support of SIF field experiments and studies of agriculture and ecosystems.

  20. Optofluidic chlorophyll lasers.

    Science.gov (United States)

    Chen, Yu-Cheng; Chen, Qiushu; Fan, Xudong

    2016-06-21

    Chlorophylls are essential for photosynthesis and also one of the most abundant pigments on earth. Using an optofluidic ring resonator of extremely high Q-factors (>10(7)), we investigated the unique characteristics and underlying mechanism of chlorophyll lasers. Chlorophyll lasers with dual lasing bands at 680 nm and 730 nm were observed for the first time in isolated chlorophyll a (Chla). Particularly, a laser at the 730 nm band was realized in 0.1 mM Chla with a lasing threshold of only 8 μJ mm(-2). Additionally, we observed lasing competition between the two lasing bands. The presence of laser emission at the 680 nm band can lead to quenching or significant reduction of laser emission at the 730 nm band, effectively increasing the lasing threshold for the 730 nm band. Further concentration-dependent studies, along with theoretical analysis, elucidated the mechanism that determines when and why the laser emission band appears at one of the two bands, or concomitantly at both bands. Finally, Chla was exploited as the donor in fluorescence resonance energy transfer to extend the laser emission to the near infrared regime with an unprecedented wavelength shift as large as 380 nm. Our work will open a door to the development of novel biocompatible and biodegradable chlorophyll-based lasers for various applications such as miniaturized tunable coherent light sources and in vitro/in vivo biosensing. It will also provide important insight into the chlorophyll fluorescence and photosynthesis processes inside plants. PMID:27220992

  1. Monitoring Wnt Signaling in Zebrafish Using Fluorescent Biosensors.

    Science.gov (United States)

    Facchinello, Nicola; Schiavone, Marco; Vettori, Andrea; Argenton, Francesco; Tiso, Natascia

    2016-01-01

    In this chapter, we are presenting methods to monitor and quantify in vivo canonical Wnt signaling activities at single-cell resolution in zebrafish. Our technology is based on artificial enhancers, obtained by polymerization of TCF binding elements, cloned upstream to ubiquitous or tissue-specific promoters. The different promoter/enhancer combinations are used to drive fluorescent protein reporter constructs integrated in the zebrafish germline by microinjection of fertilized zebrafish eggs. Fish with a single integration site are selected by Mendelian analysis of fluorescent carriers, and heterozygous offspring are used to monitor and quantify canonical Wnt activities. Open source public domain software such as ImageJ/Fiji is used to calculate the integrated densities in the region of interest and compare the effect of experimental conditions on control and treated animals. PMID:27590154

  2. [Effects of plastic film mulching and rain harvesting modes on chlorophyll fluorescence characteristics, yield and water use efficiency of dryland maize].

    Science.gov (United States)

    Li, Shang-Zhong; Fan, Ting-Lu; Wang, Yong; Zhao, Gang; Wang, Lei; Tang, Xiao-Ming; Dang, Yi; Zhao, Hui

    2014-02-01

    The differences on chlorophyll fluorescence parameters, yield and water use efficiency of dryland maize were compared among full plastic film mulching on double ridges and planting in catchment furrows (FFDRF), half plastic film mulching on double ridges and planting in catchment furrows (HFDRF), plastic film mulching on ridge and planting in film-side (FS), and flat planting with no plastic film mulching (NM) under field conditions in dry highland of Loess Plateau in 2007-2012. The results showed that fluorescence yield (Fo), the maximum fluorescence yield (Fm), light-adapted fluorescence yield when PS II reaction centers were totally open (F), light-adapted fluorescence yield when PS II reaction centers closed (Fm'), the maximal photochemical efficiency of PS II (Fv/Fm), the actual photochemical efficiency of PS II in the light (Phi PS II), the relative electron transport rate (ETR), photochemical quenching (qP) and non-photochemical quenching (qN) in maize leaves of FFDRF were higher than that of control (NM), and the value of 1-qP was lower than that of control, at 13:00, chlorophyll fluorescence parameters values of FFDRF was significantly higher than control, which were increased by 5.3%, 56.8%, 10.7%, 36.3%, 23.6%, 56.7%, 64.4%, 45.5%, 23.6% and -55.6%, respectively, compared with the control. Yield and water use efficiency of FFDRF were the highest in every year no matter dry year, normal year, humid year and hail disaster year. Average yield and water use efficiency of FFDRF were 12,650 kg x hm(-2) and 40.4 kg x mm(-1) x hm(-2) during 2007-2012, increased by 57.8% and 61.6% compared with the control, respectively, and also significantly higher compared with HFDRF and PS. Therefore, it was concluded that FFDRF had significantly increased the efficiency of light energy conversion and improved the production capacity of dryland maize. PMID:24830246

  3. Effects of di-n-butyl phthalate and di (2-ethylhexyl) phthalate on the growth, photosynthesis, and chlorophyll fluorescence of wheat seedlings.

    Science.gov (United States)

    Gao, Minling; Qi, Yun; Song, Wenhua; Xu, Haoran

    2016-05-01

    Phthalates are commonly used man-made chemicals that can be released into soil, water, and the atmosphere. The potential toxicity of phthalates on wheat seedlings has not been well studied. To better understand the deleterious effects of di-n-butyl phthalate (DBP) and di (2-ethylhexyl) phthalate (DEHP) on wheat seedlings, their influences on the following were investigated: plant growth, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), intercellular CO2 concentration (Ci), chlorophyll content, initial fluorescence (F0), maximal photochemical efficiency (Fv/Fm), photochemical quenching (qP), non-photochemical quenching (qN), effective quantum yield of photosystem II (ΦPSII), and photosynthetic electron transport rate (ETR). Compared with the control, the growth indices (plant height, fresh and dry weights of shoots, fresh and dry weights of roots), Pn, Gs, Tr, Ci, chlorophyll content, Fv/Fm, qP, ΦPSII, and ETR decreased in the 5 μg mL(-1) and 10 μg mL(-1) DBP and DEHP treatments, whereas F0 and qN increased. When wheat seedlings were treated with 20 μg mL(-1) of DBP and DEHP, the growth indices, Pn, Gs, Tr, chlorophyll content, Fv/Fm, qP, qN, ΦPSII, and ETR decreased significantly, whereas Ci and F0 increased. A decrease in the Pn of wheat seedlings was mainly caused by stomatal limitation in the 5 μg mL(-1) and 10 μg mL(-1) DBP and DEHP treatments. However, stomatal and non-stomatal limitations may have caused the reduction in Pn in the 20 μg mL(-1) DBP and DEHP treatments. Notably, the noxious effect of DBP on the wheat seedlings was significantly greater than that of DEHP. PMID:26928333

  4. The chlorophyll a fluorescence induction curve in the green microalga Haematococcus pluvialis: further insight into the nature of the P-S-M fluctuation and its relationship with the "low-wave" phenomenon at steady-state.

    Science.gov (United States)

    Fratamico, Anthony; Tocquin, Pierre; Franck, Fabrice

    2016-06-01

    Chlorophyll fluorescence is an information-rich signal which provides an access to the management of light absorbed by PSII. A good example of this is the succession of fast fluorescence fluctuations during light-induced photosynthetic induction after dark-adaptation. During this period, the fluorescence trace exhibits several inflexion points: O-J-I-P-S-M-T. Whereas the OJIP part of this kinetics has been the subject of many studies, the processes that underly the PSMT transient are less understood. Here, we report an analysis of the PSMT phase in the green microalga Haematococcus pluvialis in terms of electron acceptors and light use by photochemistry, fluorescence and non-photochemical quenching (NPQ). We identify additional sub-phases between P and S delimited by an inflexion point, that we name Q, found in the second time scale. The P-Q phase expresses a transient photochemical quenching specifically due to alternative electron transport to oxygen. During the transition from Q to S, the NPQ increases and then relaxes during the S-M phase in about 1 min. It is suggested that this transient NPQ observed during induction is a high energy state quenching (qE) dependent on the alternative electron transport to molecular oxygen. We further show that this NPQ is of the same nature than the NPQ, known as the low-wave phenomenon, which is transiently observed after a saturating light pulse given at steady-state. In both cases, the NPQ is oxygen-dependent. This NPQ is observed at external pH 6.0, but not at pH 7.5, which seems correlated with faster saturation of the PQ pool at pH 6.0. PMID:26980274

  5. Photosynthetic activity, chlorophyll-fluorescence parameters and pigment content of differently damaged spruces at the Schoellkopf (Northern Black Forest). Photosyntheseaktivitaet, Chlorophyllfluoreszenzparameter und Pigmentgehalt unterschiedlich geschaedigter Fichten am Schoellkopf (Nordschwarzwald)

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenthaler, H.K.; Rinderle, U.; Burkart, S.; Hak, R. (Karlsruhe Univ. (T.H.) (Germany, F.R.). Botanisches Inst. 2)

    1990-04-01

    At the new PEF-site Schoellkopf (840 m above see level) various physiological parameters were determined from one relatively healthy (tree No. 13) and two differently damaged spruces (tree No. 17 and 2): The netto assimilation rate P{sub N} (on a needle area and a chlorophyl basis), respiration, transpiration and stomata conductivity (gH{sub 2}O), the content of photosynthetic pigments (chlorophyll a+b, carotenoids x+c), the pigment ratios (a/b; a+b/x+c) and various parameters of the in vivo chlorophyll fluorescence (Rfd-values at 690 and 730 nm, the fluorescence ratio F690/F730; quenching-coefficients qP and qNP, the ratio Fm/Fo and Fv/Fm). Stress and damage are preferentially indicated by lower values of the chlorophyll content, the pigment ratio a+b/x+c, the assimilation rate P{sub N} and the hight of the saturation pulse spikes (g-h) as well as increased values of the coefficient qNP and the fluorescence ratio F690/F730. The differential dynamics of the chlorophyll content and the photosynthetic activity between the needles of 'healthy' and damaged spruces during the year 1989 (4 sampling dates) are presented. (orig.).

  6. Varietal differences in photosynthetic characters and chlorophyll fluorescence induction kinetics parameters among intergeneric progeny derived from Oryza×Sorghum, its parents, and hybrid rice

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A comparative study on the photosynthetic parameters among intergeneric progenies derived from Oryza sativa L.×Sorghum vulgare L., its maternal parent Gui 630 and commercial 3-line hybrid rice Shanyou 63 in pot experiment in greenhouse was conducted. The morphological and photosynthetic characters of canopy leaves and chlorophyll fluorescence kinetic parameters including Fv/Fm, Fv/F0, photochemical quenching coefficient and non-photochemical coefficient of canopy leaves of 3 varieties were measured. The results showed the progeny, Yuanyou 1, derived from an intergeneric cross of rice and sorghum possesses better canopy spatial architecture with thicker, heavier and bigger canopy leaf than its maternal parent Gui 630. Higher photosynthetic rate due to higher chlorophyll content, higher primary energy transformation efficiency, potential of PSII and non-photochemical quenching coefficient (qE) were also measured in Yuanyou 1. These explain partly why the intergeneric progeny has higher biomass production, and better tolerance to adverse conditions and higher field yields even under stress conditions.

  7. Effects of sand burial on biomass, chlorophyll fluores-cence and extracellular polysaccharides of man-made cyanobacterial crusts under experimental conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Soil cyanobacterial crusts occur throughout the world, especially in the semiarid and arid regions. It always encounters sand burial, which is an important feature of mobile sand dunes. A greenhouse study was conducted to determine the effects of sand burial on biomass, chlorophyll fluorescence and extracellular polysaccharides of man-made cyanobacterial crusts in six periods of time (0, 5, 10, 15, 20 and 30 d after burying) and at five depths (0, 0.2, 0.5, 1 and 2cm). The results indicated that with the increase of the burial time and burial depth extracellular polysaccharides content and Fv/Fm decreased correspondingly and there were no significant differences between 20 and 30 burial days under dif-ferent burial depths. The degradation of chlorophyll a content appeared only at 20 and 30 burial days and there was also no significant difference between them under different burial depths. It was also observed a simultaneous decrease of the values of the Fv/Fm and the content of extracellular poly-saccharides happened in the crusted cyanobacterium Microcoleus vaginatus Gom. It may suggest that there exists a relationship between extracellular polysaccharides and recovery of the activity of pho-tosystem II (PS II) after rehydration.

  8. Varietal differences in photosynthetic characters and chlorophyll fluorescence induction kinetics parameters among intergeneric progeny derived from Oryza×Sorghum, its parents, and hybrid rice

    Institute of Scientific and Technical Information of China (English)

    KatsuyoshiShimizu; 唐建军; 陈欣

    2002-01-01

    A comparative study on the photosynthetic parameters among intergeneric progenies derived from Oryza sativa L.× Sorghum vulgare L. , its maternal parent Gui 630 and commercial 3-line hybrid rice Shanyou 63 in pot experiment in greenhouse was conducted. The morphological and photosynthetic characters of canopy leaves and chlorophyll fluorescence kinetic pm'mneters including Fv/Fm, Fv/F0, photochemical quenching coefficient and non-photochemical coefficient of canopy leaves of 3 varieties were measured. The results showed the progeny, Yuanyou 1, derived from an intergeneric cross of rice and sorghum possesses better canopy spatial architecture with thicker, heavier and bigger canopy leaf than its maternal parent Gui 630.Higher photosynthetic rate due to higher chlorophyll content, higher primary energy transformation efficiency,potential of PSII and non-photochemieal quenching coefficient (qE) were also measured in Yuanyou 1. These explain partly why the intergeneric progeny has higher biomass production, and better tolerance to adverse conditions and higher field yields even under stress conditions.

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

    International Nuclear Information System (INIS)

    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+. QA- reoxidation test revealed that amoxicillin hinders electron transfer from QA- to QB/QB- and more QA- is oxidized through S2(QAQB)- charge recombination. Analysis of PSII heterogeneity demonstrated that an exposure to amoxicillin increases the proportion of inactive PSII (PSIIX) centers and the proportion of PSII centers with small antenna (PSIIβ). These changes finally result in deterioration of full photosynthesis performance

  10. 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

  11. On the calibration of large-scale fluorometric chlorophyll measurements from towed undulating vehicles

    Science.gov (United States)

    Strass, Volker

    1990-03-01

    Calibrating in situ fluorescence profiles to give the concentration of chlorophyll a at high resolution on the oceanic gyre scale must take into account large variations of fluorescence yield R (the ratio of the fluorescence signal and the chlorophyll concentration within the fluorometer detection volume). The calibration method suggested in this paper has been developed to handle fluorescence measurements made from a towed undulating vehicle along a section about 2000 km long between the Azores and Greenland repeated during the years 1984-1986. The calibration is based on equally spaced samples with photometrically determined near-surface chlorophyll concentrations and incorporates profiles of solar irradiance as auxillary variable. Judging from the auto-correlation function of R, the large variations of fluorescence yield are well resolved by the time interval of 4 h (corresponding to a horizontal distance of about 65 km) between adjacent chlorophyll samples. Using a filter based on the auto-correlation function the variability of yield is smoothed; the smoothed yield function is employed to calibrate the fluoresence signal continuously, in which yield between supporting points is interpreted linearly. Significant correlations of R with solar irradiance appear to be negative; this ambient-light-dependent fluorescence quenching is eliminated during calibration. The relative error in the chlorophyll concentration derived in this way is estimated to be 4% near the surface and 15% deeper down. The suggested calibration method is as accurate as more expensive procedures involving bottle cast series.

  12. 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

  13. 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.

  14. The impact of cell-specific absorption properties on the correlation of electron transport rates measured by chlorophyll fluorescence and photosynthetic oxygen production in planktonic algae.

    Science.gov (United States)

    Blache, Ulrich; Jakob, Torsten; Su, Wanwen; Wilhelm, Christian

    2011-08-01

    Photosynthesis-irradiance (P-E)-curves describe the photosynthetic performance of autotrophic organisms. From these P-E-curves the photosynthetic parameters α-slope, P(max), and E(k) can be deduced which are often used to characterize and to compare different organisms or organisms in acclimation to different environmental conditions. Particularly, for in situ-measurements of P-E curves of phytoplankton the analysis of variable chlorophyll fluorescence proved its potential as a sensitive and rapid method. By using Chlorella vulgaris (Trebouxiophyceae), Nannochloropsis salina (Eustigmatophyceae), Skeletonema costatum and Cyclotella meneghiniana (Bacillariophyceae), the present study investigated the influence of cellular bio-optical properties on the correlation of the photosynthetic parameters derived from fluorescence-based P-E-curves with photosynthetic parameters obtained from the measurement of oxygen evolution. It is demonstrated that small planktonic algae show a wide range of cellular absorptivity which was subject to species-specifity, growth stage and environmental conditions, e.g. nutrient limitation. This variability in bio-optical properties resulted in a great deviation of relative electron transport rates (rETRs) from oxygen-based photosynthesis rates. Thus, the photosynthetic parameters α-slope and P(max) derived from rETRs strongly depend on the specific cellular absorptivity and cannot be used to compare the photosynthetic performance of cells with different optical properties. However, it was shown that E(k) is independent of cellular absorptivity and could be used to compare samples with unknown optical properties. PMID:21571541

  15. Effects of Shading Stress and Light Recovery on the Photosynthesis Characteristic and Chlorophyll Fluorescence Characteristic of Fragaria Ananassa Duch. cv. Toyonoka

    Directory of Open Access Journals (Sweden)

    Renyan Duan

    2013-06-01

    Full Text Available Light is an important resource for plant growth and development, crops need to change their physiological characteristics to different light environments. Fragaria ananassa Duch. cv. Toyonoka. is an important economic plant which is widely planted at home. A greenhouse experiment was conducted from April 2010 with different sun-shading treatment, 85% (CK, 60% (T1, 35% (T2 and 10% (T3. After 7 days of shading stress, the physiological characteristics were slowly recovered. The results showed that (1 Under shading condition, Light saturation rate (Amax, Apparent Quantum Yield (AQY, Carboxylation Efficiency (CE, dark respiration (Rd, Light Saturation Point (LSP and Light Compensation Point (LCP became lower. (2 The maximal fluorescence (Fm, light energy transformation efficiency of PS II (Fv/Fm, actual photochemical efficiency of PS II in the light (Yield, photochemical quenching coefficient (qP declined with shading stress increase. (3 There were significant difference in the chlorophyll fluorescence parameters among different treatment groups by the end of sun-shading treatment (p<0.05. After the light was recovered, the physiological characteristics could rapidly recover under low shading stress and moderate shading stress, while in severe shading stress the physiological characteristics hardly recover.

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

    Science.gov (United States)

    Singh, Shardendu K; Reddy, Vangimalla R

    2015-10-01

    To evaluate the response of CO2 assimilation rate (PN) and various chlorophyll fluorescence (CF) parameters to phosphorus (P) nutrition, soybean plants were grown in controlled environment with sufficient (0.50mM) and deficient (0.10 and 0.01 mM) phosphate (P) supply under ambient and elevated CO2 (aCO2, 400 and eCO2, 800 μmol mol(-1), respectively). Measurements were made at ambient (21%) and low (2%) O2 concentrations. Results showed strong correlation of leaf P concentration with PN and CF parameters. The P deficiency showed parallel decreases in PN, and CF parameters including quantum efficiency (Fv'/Fm'), quantum yield of photosystem II (ΦPSII), electron transport rate (JF), and photochemical quenching (qP). The Fv'/Fm' decreased as a result of greater decline in maximal (Fm') than minimal (Fo') fluorescence. The eCO2 stimulated PN especially under higher leaf P concentrations. Low O2 also stimulated PN but only at aCO2. The photosynthetic carbon reduction (PCR, signified by PN) and photorespiratory carbon oxidation cycles (PCO, signified photorespiration as indicated by ratio of JF to gross PN and % increase in PN at 2% O2) was the major electron sinks. However, the presence of alternative electron sink was also evident as determined by the difference between the electron transport calculated from chlorophyll fluorescence and gas exchange measurements. Alternative electron sink declined at lower leaf P concentration suggesting its minor role in photochemical energy consumption, thus dissipation of the excess excitation pressure of PSII reaction center under P deficiency. The JF/PG and % increase in PN at 2 versus 21% O2 remained consistent across leaf P concentration suggesting PCO cycle as an important mechanism to dissipate excess excitation energy in P deficient leaves. The severe decline of Fv'/Fm', ΦPSII, JF and qP under P deficiency also suggested the occurrences of excess radiant energy dissipation by non-photochemical quenching mechanisms. Critical

  17. Diurnal and seasonal dynamics of canopy-level solar-induced chlorophyll fluorescence and spectral reflectance indices in a cornfield

    Science.gov (United States)

    A collaborative field campaign was undertaken to examine the temporal dynamics of canopy-level solar-induced fluorescence (SIF) and the Photochemical Reflectance Index (PRI) in conjunction with photosynthetic light use efficiency (LUE) obtained from fluxes measured at an instrumented tower. We condu...

  18. Sun-induced Chlorophyll fluorescence and PRI improve remote sensing GPP estimates under varying nutrient availability in a typical Mediterranean savanna ecosystem

    Directory of Open Access Journals (Sweden)

    O. Perez-Priego

    2015-07-01

    Full Text Available This study investigates the performances of different optical indices to estimate gross primary production (GPP of herbaceous stratum in a Mediterranean savanna with different Nitrogen (N and Phosphorous (P availability. Sun-induced chlorophyll Fluorescence yield computed at 760 nm (Fy760, scaled-photochemical reflectance index (sPRI, MERIS terrestrial-chlorophyll index (MTCI and Normalized difference vegetation index (NDVI were computed from near-surface field spectroscopy measurements collected using high spectral resolution spectrometers covering the visible near-infrared regions. GPP was measured using canopy-chambers on the same locations sampled by the spectrometers. We hypothesized that light-use efficiency (LUE models driven by remote sensing quantities (RSM can better track changes in GPP caused by nutrient supplies compared to those driven exclusively by meteorological data (MM. Particularly, we compared the performances of different RSM formulations – relying on the use of Fy760 or sPRI as proxy for LUE and NDVI or MTCI as fraction of absorbed photosynthetically active radiation (fAPAR – with those of classical MM. Results showed significantly higher GPP in the N fertilized experimental plots during the growing period. These differences in GPP disappeared in the drying period when senescence effects masked out potential differences due to plant N content. Consequently, although MTCI was tightly related to plant N content (r2 = 0.86, p r2 = 0.45, p cv = 127, MEcv = 0.879 outperformed RSM (AICcv = 140, MEcv = 0.8737 when soil moisture was used to constrain the seasonal dynamic of LUE. However, residual analyses demonstrated that MM is predictively inaccurate whenever no climatic variable explicitly reveals nutrient-related changes in the LUE parameter. These results put forward that RSM is a valuable means to diagnose nutrient-induced effects on the photosynthetic activity.

  19. 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.

  20. Responses of chlorophyll fluorescence and nitrogen level of Leymus chinensis Seedling to changes of soil moisture and temperature

    Institute of Scientific and Technical Information of China (English)

    XU Zhen-zhu; ZHOU Guang-sheng; LI Hui

    2004-01-01

    Controlled experiment of Leymus chinensis seedlings grown in the environmental growth chambers at 3 soilmoisture levels and 3 temperature levels was conducted in order to improve the understanding how leafphotosynthetic parameters will respond to climatic change. The results indicated that soil drought and hightemperature decreased the photochemical efficiency of photosystem (Fv/Fm ), the overall photochemical quantumyield of PSIl(yield), the coefficient of photochemical fluorescence quenching(qp), but increased the coefficient ofnon-photochemical fluorescence quenching(qN). Severe soil drought would decrease Fv/Fm and yield by 3.12% and 37.04% under 26℃ condition, respectively, and 6.60% and 73.33% under 32℃ condition, respectively, suggesting that higher temperature may enhance the negative effects of soil drought. All the soil drought treatments resulted in the decline in leaf nitrogen content. There was no significant effect of temperature on leaf nitrogen level, but higher temperature significantly reduced the root nitrogen content and the ratio of root nitrogen to leaf nitrogen, indicating the different strategies of adaptation to soil drought and temperature. It was also implied that higher temperature would enhance the effect of soil drought on leaf photosynthetic capacity, decrease the adaptability of Leymus chinensis to drought.

  1. 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

  2. Effects of nitrogen form on growth,CO2 assimilation,chlorophyll fluorescence,and photosynthetic electron allocation in cucumber and rice plants

    Institute of Scientific and Technical Information of China (English)

    Yan-hong ZHOU; Yi-li ZHANG; Xue-min WANG; Jin-xia CUI; Xiao-jian XIA; Kai SHI; Jing-quan YU

    2011-01-01

    Cucumber and rice plants with varying ammonium(NH4+)sensitivities were used to examine the effects of different nitrogen(N)sources on gas exchange,chlorophyll(ChI)fluorescence quenching,and photosynthetic electron allocation.Compared to nitrate(NO3-)-grown plants,cucumber plants grown under NH4+-nutdtion showed decreased plant growth,net photosynthetic rate,stomatal conductance,intercellular carbon dioxide(CO2)level,transpiration rate,maximum photochemical efficiency of photosystem Ⅱ,and O2-independent alternative electron flux,and increased O2-dependent alternative electron flux.However,the N source had little effect on gas exchange,ChI a fluorescence parameters,and photosynthetic electron allocation in rice plants,except that NH4+-grown plants had a higher O2-independent alternative electron flux than NO3--grown plants.NO3-reduction activity was rarely detected in leaves of NH4+-grown cucumber plants,but was high in NH4+-grown rice plants.These results demonstrate that significant amounts of photosynthetic electron transport were coupled to NO3-assimilation,an effect more significant in NO3--grown plants than in NH4+-grown plants.Meanwhile,NH4+-tolerant plants exhibited a higher demand for the reduced form of nicotinamide adenine dinucleotide phosphate(NADPH)for NO3-reduction,regardless of the N form supplied,while NH4+-sensitive plants had a high water-water cycle activity when NH4+was supplied as the sole N source.

  3. 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.

  4. Mapping intercellular CO2 mole fraction (Ci) in rosa rubiginosa leaves fed with abscisic acid by using chlorophyll fluorescence imaging. Significance Of ci estimated from leaf gas exchange

    Science.gov (United States)

    Meyer; Genty

    1998-03-01

    Imaging of photochemical yield of photosystem II (PSII) computed from leaf chlorophyll fluorescence images and gas-exchange measurements were performed on Rosa rubiginosa leaflets during abscisic acid (ABA) addition. In air ABA induced a decrease of both the net CO2 assimilation (An) and the stomatal water vapor conductance (gs). After ABA treatment, imaging in transient nonphotorespiratory conditions (0.1% O2) revealed a heterogeneous decrease of PSII photochemical yield. This decline was fully reversed by a transient high CO2 concentration (7400 mol mol-1) in the leaf atmosphere. It was concluded that ABA primarily affected An by decreasing the CO2 supply at ribulose-1,5-bisphosphate carboxylase/oxygenase. Therefore, the An versus intercellular mole fraction (Ci) relationship was assumed not to be affected by ABA, and images of Ci and gs were constructed from images of PSII photochemical yield under nonphotorespiratory conditions. The distribution of gs remained unimodal following ABA treatment. A comparison of calculations of Ci from images and gas exchange in ABA-treated leaves showed that the overestimation of Ci estimated from gas exchange was only partly due to heterogeneity. This overestimation was also attributed to the cuticular transpiration, which largely affects the calculation of the leaf conductance to CO2, when leaf conductance to water is low. PMID:9501127

  5. HIGH CHLOROPHYLL FLUORESCENCE145 Binds to and Stabilizes the psaA 5' UTR via a Newly Defined Repeat Motif in Embryophyta.

    Science.gov (United States)

    Manavski, Nikolay; Torabi, Salar; Lezhneva, Lina; Arif, Muhammad Asif; Frank, Wolfgang; Meurer, Jörg

    2015-09-01

    The seedling-lethal Arabidopsis thaliana high chlorophyll fluorescence145 (hcf145) mutation leads to reduced stability of the plastid tricistronic psaA-psaB-rps14 mRNA and photosystem I (PSI) deficiency. Here, we genetically mapped the HCF145 gene, which encodes a plant-specific, chloroplast-localized, modular protein containing two homologous domains related to the polyketide cyclase family comprising 37 annotated Arabidopsis proteins of unknown function. Two further highly conserved and previously uncharacterized tandem repeat motifs at the C terminus, herein designated the transcript binding motif repeat (TMR) domains, confer sequence-specific RNA binding capability to HCF145. Homologous TMR motifs are often found as multiple repeats in quite diverse proteins of green and red algae and in the cyanobacterium Microcoleus sp PCC 7113 with unknown function. HCF145 represents the only TMR protein found in vascular plants. Detailed analysis of hcf145 mutants in Arabidopsis and Physcomitrella patens as well as in vivo and in vitro RNA binding assays indicate that HCF145 has been recruited in embryophyta for the stabilization of the psaA-psaB-rps14 mRNA via specific binding to its 5' untranslated region. The polyketide cyclase-related motifs support association of the TMRs to the psaA RNA, presumably pointing to a regulatory role in adjusting PSI levels according to the requirements of the plant cell. PMID:26307378

  6. 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.

  7. Sun-induced chlorophyll fluorescence from high-resolution imaging spectroscopy data to quantify spatio-temporal patterns of photosynthetic function in crop canopies.

    Science.gov (United States)

    Pinto, Francisco; Damm, Alexander; Schickling, Anke; Panigada, Cinzia; Cogliati, Sergio; Müller-Linow, Mark; Balvora, Agim; Rascher, Uwe

    2016-07-01

    Passive detection of sun-induced chlorophyll fluorescence (SIF) using spectroscopy has been proposed as a proxy to quantify changes in photochemical efficiency at canopy level under natural light conditions. In this study, we explored the use of imaging spectroscopy to quantify spatio-temporal dynamics of SIF within crop canopies and its sensitivity to track patterns of photosynthetic activity originating from the interaction between vegetation structure and incoming radiation as well as variations in plant function. SIF was retrieved using the Fraunhofer Line Depth (FLD) principle from imaging spectroscopy data acquired at different time scales a few metres above several crop canopies growing under natural illumination. We report the first maps of canopy SIF in high spatial resolution. Changes of SIF were monitored at different time scales ranging from quick variations under induced stress conditions to seasonal dynamics. Natural changes were primarily determined by varying levels and distribution of photosynthetic active radiation (PAR). However, this relationship changed throughout the day demonstrating an additional physiological component modulating spatio-temporal patterns of SIF emission. We successfully used detailed SIF maps to track changes in the canopy's photochemical activity under field conditions, providing a new tool to evaluate complex patterns of photosynthesis within the canopy. PMID:26763162

  8. 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. PMID:25923517

  9. Deriving C4 photosynthetic parameters from combined gas exchange and chlorophyll fluorescence using an Excel tool: theory and practice.

    Science.gov (United States)

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

    2016-06-01

    The higher photosynthetic potential of C4 plants has led to extensive research over the past 50 years, including C4 -dominated natural biomes, crops such as maize, or for evaluating the transfer of C4 traits into C3 lineages. Photosynthetic gas exchange can be measured in air or in a 2% Oxygen mixture using readily available commercial gas exchange and modulated PSII fluorescence systems. Interpretation of these data, however, requires an understanding (or the development) of various modelling approaches, which limit the use by non-specialists. In this paper we present an accessible summary of the theory behind the analysis and derivation of C4 photosynthetic parameters, and provide a freely available Excel Fitting Tool (EFT), making rigorous C4 data analysis accessible to a broader audience. Outputs include those defining C4 photochemical and biochemical efficiency, the rate of photorespiration, bundle sheath conductance to CO2 diffusion and the in vivo biochemical constants for PEP carboxylase. The EFT compares several methodological variants proposed by different investigators, allowing users to choose the level of complexity required to interpret data. We provide a complete analysis of gas exchange data on maize (as a model C4 organism and key global crop) to illustrate the approaches, their analysis and interpretation. © 2015 John Wiley & Sons Ltd. PMID:26286697

  10. Sun-induced Chlorophyll fluorescence and PRI improve remote sensing GPP estimates under varying nutrient availability in a typical Mediterranean savanna ecosystem

    Science.gov (United States)

    Perez-Priego, O.; Guan, J.; Rossini, M.; Fava, F.; Wutzler, T.; Moreno, G.; Carvalhais, N.; Carrara, A.; Kolle, O.; Julitta, T.; Schrumpf, M.; Reichstein, M.; Migliavacca, M.

    2015-07-01

    This study investigates the performances of different optical indices to estimate gross primary production (GPP) of herbaceous stratum in a Mediterranean savanna with different Nitrogen (N) and Phosphorous (P) availability. Sun-induced chlorophyll Fluorescence yield computed at 760 nm (Fy760), scaled-photochemical reflectance index (sPRI), MERIS terrestrial-chlorophyll index (MTCI) and Normalized difference vegetation index (NDVI) were computed from near-surface field spectroscopy measurements collected using high spectral resolution spectrometers covering the visible near-infrared regions. GPP was measured using canopy-chambers on the same locations sampled by the spectrometers. We hypothesized that light-use efficiency (LUE) models driven by remote sensing quantities (RSM) can better track changes in GPP caused by nutrient supplies compared to those driven exclusively by meteorological data (MM). Particularly, we compared the performances of different RSM formulations - relying on the use of Fy760 or sPRI as proxy for LUE and NDVI or MTCI as fraction of absorbed photosynthetically active radiation (fAPAR) - with those of classical MM. Results showed significantly higher GPP in the N fertilized experimental plots during the growing period. These differences in GPP disappeared in the drying period when senescence effects masked out potential differences due to plant N content. Consequently, although MTCI was tightly related to plant N content (r2 = 0.86, p < 0.01), it was poorly related to GPP (r2 = 0.45, p < 0.05). On the contrary sPRI and Fy760 correlated well with GPP during the whole measurement period. Results revealed that the relationship between GPP and Fy760 is not unique across treatments but it is affected by N availability. Results from a cross validation analysis showed that MM (AICcv = 127, MEcv = 0.879) outperformed RSM (AICcv = 140, MEcv = 0.8737) when soil moisture was used to constrain the seasonal dynamic of LUE. However, residual analyses

  11. Sun-induced chlorophyll fluorescence and photochemical reflectance index improve remote-sensing gross primary production estimates under varying nutrient availability in a typical Mediterranean savanna ecosystem

    Science.gov (United States)

    Perez-Priego, O.; Guan, J.; Rossini, M.; Fava, F.; Wutzler, T.; Moreno, G.; Carvalhais, N.; Carrara, A.; Kolle, O.; Julitta, T.; Schrumpf, M.; Reichstein, M.; Migliavacca, M.

    2015-11-01

    This study investigates the performances of different optical indices to estimate gross primary production (GPP) of herbaceous stratum in a Mediterranean savanna with different nitrogen (N) and phosphorous (P) availability. Sun-induced chlorophyll fluorescence yield computed at 760 nm (Fy760), scaled photochemical reflectance index (sPRI), MERIS terrestrial-chlorophyll index (MTCI) and normalized difference vegetation index (NDVI) were computed from near-surface field spectroscopy measurements collected using high spectral resolution spectrometers covering the visible near-infrared regions. GPP was measured using canopy chambers on the same locations sampled by the spectrometers. We tested whether light-use efficiency (LUE) models driven by remote-sensing quantities (RSMs) can better track changes in GPP caused by nutrient supplies compared to those driven exclusively by meteorological data (MM). Particularly, we compared the performances of different RSM formulations - relying on the use of Fy760 or sPRI as a proxy for LUE and NDVI or MTCI as a fraction of absorbed photosynthetically active radiation (fAPAR) - with those of classical MM. Results showed higher GPP in the N-fertilized experimental plots during the growing period. These differences in GPP disappeared in the drying period when senescence effects masked out potential differences due to plant N content. Consequently, although MTCI was closely related to the mean of plant N content across treatments (r2 = 0.86, p < 0.01), it was poorly related to GPP (r2 = 0.45, p < 0.05). On the contrary sPRI and Fy760 correlated well with GPP during the whole measurement period. Results revealed that the relationship between GPP and Fy760 is not unique across treatments, but it is affected by N availability. Results from a cross-validation analysis showed that MM (AICcv = 127, MEcv = 0.879) outperformed RSM (AICcv =140, MEcv = 0.8737) when soil moisture was used to constrain the seasonal dynamic of LUE. However

  12. 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

  13. 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.

  14. 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

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

    OpenAIRE

    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 seed coat but low levels of chlorophyll were also detected in the embryo, mainly in the radicle tip. Seed chlorophyll fluorescence appeared to be a sensitive indicator of physiological maturity of tomato see...

  16. Gold nanoparticle-fluorophore complex for conditionally fluorescing signal mediator

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jianting [Department of Chemical Engineering University of, Louisville, KY 40292 (United States); Achilefu, Samuel [Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Nantz, Michael [Department of Chemistry, University of Louisville, Louisville, KY 40292 (United States); Kang, Kyung A., E-mail: kyung.kang@louisville.edu [Department of Chemical Engineering University of, Louisville, KY 40292 (United States)

    2011-06-10

    Fluorescent contrast agents with high specificity and sensitivity are valuable for accurate disease detection and diagnosis. Spherical gold nanoparticles (GNPs) can be smartly utilized for developing highly effective agents. The strong electromagnetic (plasmon) field on their surface can be very effective in influencing the electrons of fluorophores and, thus, manipulating the fluorescence output (i.e., either quenching or enhancement). Fluorescence quenching can be used for negative sensing, or for conditional de-quenching to increase the specificity. Fluorescence enhancement allows sensing to be more sensitive. The level of fluorescence alteration depends on the GNP size, the excitation and emission wavelengths and quantum yield of the fluorophore, and the distance between the GNP and the fluorophore. To understand the mechanisms of the fluorescence change by GNP, we have theoretically analyzed the parameters involved in the fluorescence alteration for commonly used fluorophores, with an emphasis on quenching. The results showed that the fluorescence of fluorophores with the excitation (Ex) and emission (Ex) wavelengths close to the GNP resonance peak tended to be significantly quenched by GNPs. For those fluorophores emitting fluorescence in red or near infrared, to achieve quenching, the distance between GNP and the fluorophore was required to be very short. In general, a shorter distance resulted in more quenching. Bigger GNPs require a shorter distance to achieve the same level of quenching. The fluorescence of a fluorophore with a lower quantum yield (especially the one with emission in far-red or near-infrared) is more difficult to be quenched by GNPs (requires very short distance). Instead, it can be enhanced. Based on the theoretical study, we have developed a near-infrared contrast agent, i.e., Cypate conjugated GNP via a short peptide spacer. Normally the fluorescence of Cypate was quenched. The spacer has a motif of a substrate for urokinase type

  17. Response of grapevine leaves to plasmopara viticola infection by means of measurement of reflectance and fluorescence signals

    Czech Academy of Sciences Publication Activity Database

    Šebela, David; Olejníčková, Julie; Župčanová, A.; Sotolář, R.

    2012-01-01

    Roč. 27, č. 8 (2012), s. 229-237. ISSN 1211-8516 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Plasmopara viticola * downy mildew * grapevine * leaf tissue * susceptible varieties * chlorophyll fluorescence imaging * reflectance Subject RIV: GM - Food Processing

  18. Enhancement of Single Molecule Fluorescence Signals by Colloidal Silver Nanoparticles in Studies of Protein Translation

    OpenAIRE

    Bharill, Shashank; Chen, Chunlai; Stevens, Benjamin; Kaur, Jaskiran; Smilansky, Zeev; Mandecki, Wlodek; Gryczynski, Ignacy; Gryczynski, Zygmunt; Cooperman, Barry S.; Goldman, Yale E.

    2010-01-01

    Metal enhanced fluorescence (MEF) increased total photon emission of Cy3- and Cy5-labeled ribosomal initiation complexes near 50 nm silver particles 4- and 5.5-fold respectively. Fluorescence intensity fluctuations above shot noise, at 0.1 – 5 Hz, were greater on silver particles. Overall signal to noise ratio was similar or slightly improved near the particles. Proximity to silver particles did not compromise ribosome function, as measured by codon-dependent binding of fluorescent tRNA, dyna...

  19. Photosynthetic acclimation to photon irradiance and its relation to chlorophyll fluorescence and carbon assimilation in the halotolerant green alga Dunaliella viridis.

    Science.gov (United States)

    Gordillo, F J; Jiménez, C; Chavarría, J; Xavier Niell, F

    2001-01-01

    This work describes the long-term acclimation of the halotolerant microalga Dunaliella viridis to different photon irradiance, ranging from darkness to 1500 mumol m(-2) s(-1). In order to assess the effects of long-term photoinhibition, changes in oxygen production rate, pigment composition, xanthophyll cycle and in vivo chlorophyll fluorescence using the saturating pulse method were measured. Growth rate was maximal at intermediate irradiance (250 and 700 mumol m(-2) s(-1)). The increase in growth irradiance from 700 to 1500 mumol m(-2) s(-1) did not lead to further significant changes in pigment composition or EPS, indicating saturation in the pigment response to high light. Changes in Photosystem II optimum quantum yield (F(v)/F(m)) evidenced photoinhibition at 700 and especially at 1500 mumol m(-2) s(-1). The relation between photosynthetic electron flow rate and photosyntetic O(2) evolution was linear for cultures in darkness shifting to curvilinear as growth irradiance increased, suggesting the interference of the energy dissipation processes in oxygen evolution. Carbon assimilation efficiencies were studied in relation to changes in growth rate, internal carbon and nitrogen composition, and organic carbon released to the external medium. All illuminated cultures showed a high capability to maintain a C:N ratio between 6 and 7. The percentage of organic carbon released to the external medium increased to its maximum under high irradiance (1500 mumol m(-2) s(-1)). These results suggest that the release of organic carbon could act as a secondary dissipation process when the xanthophyll cycle is saturated. PMID:16228345

  20. Natural leaf senescence: probed by chlorophyll fluorescence, CO2 photosynthetic rate and antioxidant enzyme activities during grain filling in different rice cultivars.

    Science.gov (United States)

    Panda, Debabrata; Sarkar, Ramani Kumar

    2013-01-01

    Natural leaf senescence was investigated in four rainfed lowland rice cultivars, FR 13A (tolerant to submergence), Sabita and Sarala (adapted to medium depth, 0-50 cm stagnant flooding) and Dengi (conventional farmers' cultivar). Changes in the levels of pigment content, CO2 photosynthetic rate, photosystem II photochemistry and anti-oxidant enzyme activities of flag leaves during grain-filling stage were investigated. Chlorophyll content, photochemical efficiency of photosystem II and CO2 photosynthetic rate decreased significantly with the progress of grain-filling. Likely, the activities of antioxidant enzymes namely, superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase decreased with progress of grain-filling. A substantial difference was observed among the four cultivars for the sustainability index (SI) of different photosynthetic parameters and antioxidant enzyme activities; SIs of those parameters, in general, were lower in low yielding cultivar FR 13A compared to the other three cultivars. Among the four cultivars Sabita gave maximum grain yield. Yet, SI of Pn was greater in Sarala and Dengi compared to the Sabita. SIs of electron transport (ETo/CS), maximal photochemical efficiency (Fv/Fm), area above Fo and Fm, catalase and ascorbate peroxidase were also greater in Sarala and Dengi. The data showed that among the different Chl a fluorescence parameters, PI could be used with greater accuracy to distinguish slow and fast senescence rice cultivars during grain-filling period. It was concluded that maintaining the vitality of rice plants during grain-filling gave guarantee to synthesize carbohydrate, however greater yield could be realized provided superior yield attributing parameters are present. PMID:24381436

  1. Chlorophyll Fluorescence Characteristics of Physiologically Etiolated Cinnamomum camphora leaves%生理性黄化香樟叶绿素荧光特性的研究

    Institute of Scientific and Technical Information of China (English)

    袁梦; 陈晓娟; 秦金舟; 刘桂华

    2013-01-01

    The daily changes of chlorophyll fluorescence parameters of Cinnamomum camphora leaves at different levels of etiolation were studied .The results showed that the F0(minimal fluorescence ),Fm(maximal flu-orescence),Fm′(actual maximal fluorescence ),Fv(variable fluorescence ),Fv/Fm(optimal/maximal photochemi-cal efficiency of PSⅡ),Fm/F0(electron transfer rate ),and Fv/F0(potential activity of PSⅡ) first increased and then descended in the healthy and light-etiolated camphor leaves between 08:00-16:00,and the highest values occurred between 12:00 to 14:00.The daily change trend of N P,Q(non-photochemical quenching ) was contrary to those parameters mentioned above ,the trend was first increasing and then descending ,and the lowest values of Fm/F0 and Fv/F0 occurred in the period of 12:00 to 14:00,the chlorophyll fluorescence parameters showed a flat trend in moderate-and severe-etiolated camphor leaves .The average values of Fv/Fm in health camphor leaves were obviously higher than those in the etiolated camphor leaves .The maximal photochemical efficiency of PSⅡin the healthy camphor leaves was higher ,the average electron transfer rate and the potential activity of PSⅡshowed a descending trend .The daily average value of N P,Q in the etiolated camphora leaves was obviously higher than that in the healthy camphor leaves ,and increased with the increase of etiolation degree ,indicating that the more seriously the leaves were etiolated the higher proportion of light energy was absorbed by camphor leaves to avoid the destruction of photosynthetic tissue through hot dissipation .%对冬季不同黄化等级的香樟叶片主要叶绿素荧光参数的日变化进行了测定。结果表明:从08:00-16:00,健康和轻度黄化香樟F0(最小荧光)、Fm(最大荧光)、Fm′(光适应下的最大荧光)、Fv(可变荧光)、Fv/Fm (PSⅡ最大光能转换效率)、Fm/F0(电子传递效率)、Fv/F0(PSⅡ潜在活性)均呈现

  2. Fluorescence signals of quantum dots influenced by spatially controlled array structures

    International Nuclear Information System (INIS)

    Fluorescence signals of quantum dots (QDs) influenced by different array structures of gold-coated silicon nanorods (SiNRs) were investigated via experimental observations and two-dimensional (2D) finite element method (FEM) simulations. On the densest gold-coated SiNRs array structure, the highest QD fluorescence quenching rates were observed and on the sparsest array structure, the highest QD fluorescence enhancement rates were observed. By developing a new technique which obtains the optical image of the array structures without losing information about the QD locations, we were able to further investigate how the QD fluorescence is influenced by spatially controlled array structures.

  3. Enhancement of Single Molecule Fluorescence Signals by Colloidal Silver Nanoparticles in Studies of Protein Translation

    Science.gov (United States)

    Bharill, Shashank; Chen, Chunlai; Stevens, Benjamin; Kaur, Jaskiran; Smilansky, Zeev; Mandecki, Wlodek; Gryczynski, Ignacy; Gryczynski, Zygmunt; Cooperman, Barry S.; Goldman, Yale E.

    2011-01-01

    Metal enhanced fluorescence (MEF) increased total photon emission of Cy3- and Cy5-labeled ribosomal initiation complexes near 50 nm silver particles 4- and 5.5-fold respectively. Fluorescence intensity fluctuations above shot noise, at 0.1 – 5 Hz, were greater on silver particles. Overall signal to noise ratio was similar or slightly improved near the particles. Proximity to silver particles did not compromise ribosome function, as measured by codon-dependent binding of fluorescent tRNA, dynamics of fluorescence resonance energy transfer between adjacent tRNAs in the ribosome, and tRNA translocation induced by elongation factor G. PMID:21158483

  4. Enhancement of single-molecule fluorescence signals by colloidal silver nanoparticles in studies of protein translation.

    Science.gov (United States)

    Bharill, Shashank; Chen, Chunlai; Stevens, Benjamin; Kaur, Jaskiran; Smilansky, Zeev; Mandecki, Wlodek; Gryczynski, Ignacy; Gryczynski, Zygmunt; Cooperman, Barry S; Goldman, Yale E

    2011-01-25

    Metal-enhanced fluorescence (MEF) increased total photon emission of Cy3- and Cy5-labeled ribosomal initiation complexes near 50 nm silver particles 4- and 5.5-fold, respectively. Fluorescence intensity fluctuations above shot noise, at 0.1-5 Hz, were greater on silver particles. Overall signal-to-noise ratio was similar or slightly improved near the particles. Proximity to silver particles did not compromise ribosome function, as measured by codon-dependent binding of fluorescent tRNA, dynamics of fluorescence resonance energy transfer between adjacent tRNAs in the ribosome, and tRNA translocation induced by elongation factor G. PMID:21158483

  5. Optical Probe for Near-Infrared (NIR) Fluorescence Signal Detection with High Optical Performance and Thermal Stability

    OpenAIRE

    In Hee Shin; Joo Beom Eom; Jae Seok Park; Hyeong Ju Park; Byeong-Il Lee

    2014-01-01

    We propose a new optical probe for near-infrared (NIR) fluorescence signal detection with high optical performance and thermal stability. The optical probe is composed of an optical source part for efficient excitation of NIR fluorescence signal, a heat dissipation part for stable operation of the NIR fluorescence probe, and an optical detection part for efficient detection of NIR fluorescence signal. From a simulation by use of an optical simulation tool, Light ToolsTM, we could confirm that...

  6. Efficient signal processing for time-resolved fluorescence detection of nitrogen-vacancy spins in diamond

    Science.gov (United States)

    Gupta, A.; Hacquebard, L.; Childress, L.

    2016-03-01

    Room-temperature fluorescence detection of the nitrogen-vacancy center electronic spin typically has low signal to noise, requiring long experiments to reveal an averaged signal. Here, we present a simple approach to analysis of time-resolved fluorescence data that permits an improvement in measurement precision through signal processing alone. Applying our technique to experimental data reveals an improvement in signal to noise equivalent to a 14% increase in photon collection efficiency. We further explore the dependence of the signal to noise ratio on excitation power, and analyze our results using a rate equation model. Our results provide a rubric for optimizing fluorescence spin detection, which has direct implications for improving precision of nitrogen-vacancy-based sensors.

  7. A capillary-based probe for in situ detection of enhanced fluorescence signals

    International Nuclear Information System (INIS)

    A simple, compact, and high sensitivity capillary-based probe for the in situ detection of fluorescence signals with high sensitivity is demonstrated. A home-made single–multi-mode fiber coupler that is coaxially aligned with the capillary-based probe provides for the transmission of excitation light and the collection and transmission of fluorescence. We propose a conceptually straightforward theoretical model to optimize the factors affecting the fluorescence-capture capability of the capillary-based probe. The fluorescence signal detected by fiber-optic spectroscopy non-linearly increases with the length of the capillary-based probe. In addition, the thicker the capillary tube wall is, the less the fluorescence signals determined are. The performance of the proposed probe is evaluated experimentally by measuring the fluorescence spectra of Cy5.5 dye and blue-green algae. The experimental results show that the proposed probe provides more than a ten-fold increase in fluorescence signal compared with direct measurements by a flat-tipped multi-mode fiber probe. The advantages of the capillary-based probe, which include its simple and compact structure, excellent light collection efficiency, requirement of small sample volume, and recoverability of samples, allow its wide application to in situ detection in the medical, forensic, biological, geological, and environmental fields with high sensitivity. (letter)

  8. Chlorophyll fluorescence characteristics of Amaranthus tricolor L.under high temperature stress%高温胁迫下苋菜的叶绿素荧光特性

    Institute of Scientific and Technical Information of China (English)

    陈梅; 唐运来

    2013-01-01

    为了探明高温胁迫对苋菜(Amaranthus tricolor L.)光合过程的影响,用不同温度(25、30、35、40、45℃)处理苋菜植株1h后,随即测定了其叶绿素荧光动力学参数和快速光响应曲线特征参数的变化.结果表明:40℃以上高温胁迫下,苋菜叶片的光系统Ⅱ(PSⅡ)潜在光化学效率(Fv/Fo)、最大光化学效率(Fv/Fm)下降;最大荧光(Fm)、光合电子传递速率(ETR)、PSⅡ实际光化学效率(Yield)、光化学淬灭系数(qP)也均有所下降;而初始荧光(F.)和非光化学淬灭系数(NPQ)在40℃以上高温胁迫下显著上升.叶绿素荧光快速光响应曲线测定结果表明,初始斜率α、最大相对电子传递速率ETRmax和半饱和光强Ik在40℃以上高温胁迫下有所下降.研究表明,40℃以上高温胁迫对苋菜的光能的吸收、转换、光合电子传递和强光耐受能力等均有一定的影响.%Amaranth (Amaranthus tricolor L.) plants were exposed to several temperature levels (25,30,35,40,and 45 ℃) for 1 h,and then,the characteristic parameters of chlorophyll fluorescence and the rapid light response curves of photosynthesis were measured,aimed to understand the effects of high temperature stress on the photosynthesis process of amaranth.High temperature stress (>40 ℃) decreased the maximum fluorescence (Fm),potential photochemical efficiency (Fv/Fo),and maximum photochemical efficiency of PS Ⅱ (Fv/Fm).Simultaneously,the electron transport rate (ETR),actual photochemical efficiency of PS Ⅱ (Yield),and photochemical quenching coefficient (qP) also had some decrease.In contrast,the initial fluorescence (Fo) and non-photochemical quenching coefficient (NPQ) were increased significantly.The initial slope rate (a),maximum apparent electron transport rates (ETRmax),and half-saturation light intensity (Ik) under high temperature stress also had some decline.These results indicated that the photosynthesis of A.tricolor plants was very sensitive to high

  9. 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 t

  10. Promotion versus suppression of rat colon carcinogenesis by chlorophyllin and chlorophyll: modulation of apoptosis, cell proliferation, and β-catenin/Tcf signaling

    International Nuclear Information System (INIS)

    effect and copper promoted the number of small ACF induced by IQ. The results suggest that further investigation of the dose-response for suppression versus promotion by chlorophyll and chlorophyllin is warranted, including studies of the β-catenin/Tcf signaling pathway and its influence on cell proliferation and apoptosis in the colonic crypt

  11. Micro-scale fluorescence signals: a transition from continuous to discrete scale

    Science.gov (United States)

    Yamazaki, H.; Doubell, M. J.; Prairie, J.; Sagara, Y.; Locke, C.; Nimmo-Smith, A.

    2012-12-01

    Micro-scale aquatic ecosystems are the engine for earth's biogeochemical cycles. Phytoplankton fix inorganic carbon to organic carbon through the photosynthetic process. Although phytoplankton are single-cell organisms, they often appear in an aggregated form that elevates local fluorescence signal intensity. How intermittent are these features? We have developed a new free-fall microstructure profiler (TurboMAP-L). Fluorescence profiles measured by TurboMAP-L and a conventional fluorescence probe are in good agreement at one-meter scale average. However, the fluorescence signals revealed by the LED fluorescence probe are intermittent at cm scale. Millimeter scale fluorescence signals obtained from the laser probe are even more intermittent than the cm scale LED signals. The source of the millimeter-scale strong signals identified from the DSL images are coagulated discrete material ranging between a few 100 μm and a few millimeters scale. Unfortunately, the DSL images are not well focused, so the details of the coagulated matter are not clear. Therefore, a recently developed holographic imaging system was combined with the TurboMAP-L operation in order to identify the detail of the millimeter scale coagulated material. We show that fluorescence signals at millimeter scale exhibit high values of coefficient of variation and the signals are no longer a Gaussian process. We found a transition scale that separates a continuous Gaussian process to a discrete event series. We are also developing a new NPZ ecosystem model based on our finding. We will present the consequence of our new model that may alter the way in which the global biogeochemical cycle should be treated.

  12. Chlorophyll fluorescence of tropical tree species in a semi-deciduous forest gap Fluorescência da clorofila de espécies arbóreas tropicais em uma clareira de floresta semidecídua

    Directory of Open Access Journals (Sweden)

    Rafael Vasconcelos Ribeiro

    2004-02-01

    Full Text Available The characterization of different ecological groups in a forest formation/succession is unclear. To better define the different successional classes, we have to consider ecophysiological aspects, such as the capacity to use or dissipate the light energy available. The main objective of this work was to assess the chlorophyll fluorescence emission of tropical tree species growing in a gap of a semi-deciduous forest. Three species of different ecological groups were selected: Croton floribundus Spreng. (pioneer, P, Astronium graveolens Jacq. (early secondary, Si, and Esenbeckia febrifuga A. Juss. (late secondary, St. The potential (Fv/Fm and effective (deltaF/Fm' quantum efficiency of photosystem II, apparent electron transport rate (ETR, non-photochemical (qN and photochemical (qP quenching of fluorescence were evaluated, using a modulated fluorometer, between 7:30 and 11:00 h. Values of Fv/Fm remained constant in St, decreasing in P and Si after 9:30 h, indicating the occurrence of photoinhibition. Concerning the measurements taken under light conditions (deltaF/Fm', ETR, qP and qN, P and Si showed better photochemical performance, i.e., values of deltaF/Fm', ETR and qP were higher than St when light intensity was increased. Values of qN indicated that P and Si had an increasing tendency of dissipating the excess of energy absorbed by the leaf, whereas the opposite was found for St. The principal component analysis (PCA, considering all evaluated parameters, showed a clear distinction between St, P and Si, with P and Si being closer. The PCA results suggest that chlorophyll fluorescence may be a potential tool to differentiate tree species from distinct successional groups.A caracterização dos diferentes grupos ecológicos envolvidos nos processos de formação/sucessão florestal é ainda pouco precisa. Para melhor distinção das classes sucessionais deve-se levar em consideração aspectos ecofisiológicos, como a capacidade de

  13. Spermine detection via metal-mediated ethynylarene ‘turn-on’ fluorescence signaling

    OpenAIRE

    Fletcher, James T.; Bruck, Brent S.

    2015-01-01

    A dicarboxylated ethynylarene was shown to behave as a fluorescent chemosensor for millimolar concentrations of polyamines when mixed with Cd(II), Pb(II) or Zn(II) ions at micromolar concentrations. A bathochromic shift and intensification of fluorescence emission was observed with increasing amounts of metal ion in the presence of aqueous polyamines buffered at pH = 7.6. Such perturbations manifested as ‘turn-on’ signals from a ratiometric comparison of emission intensities at 390 nm versus ...

  14. Enhanced fluorescence cyanide detection at physiologically lethal levels: reduced ICT-based signal transduction.

    Science.gov (United States)

    Badugu, Ramachandram; Lakowicz, Joseph R; Geddes, Chris D

    2005-03-16

    Three water-soluble fluorescent probes have been specifically designed to determine free cyanide concentrations up to physiologically lethal levels, >20 microM. The probes have been designed in such a way as to afford many notable sensing features, which render them unique with regard to signal transduction, photophysical characteristics, and their application to physiological cyanide determination and safeguard. The probes are readily able to reversibly bind free aqueous cyanide with dissociation constants around 4 microM3. Subsequent cyanide binding modulates the intramolecular charge transfer within the probes, a change in the electronic properties within the probes, resulting in enhanced fluorescence optical signals as a function of increased solution cyanide concentration. The ground-state chelation with cyanide produces wavelength shifts, which also enable the probes to sense cyanide in both an excitation and emission ratiometric manner, in addition to enhanced fluorescence signaling. This has enabled a generic cyanide sensing platform to be realized that is not dependent on fluorescent probe concentration, probe photodegradation, or fluctuations in the intensity of any employed excitation sources, ideal for remote cyanide sensing applications. Further, the >600 nm fluorescence emission of the probes potentially allows for enhanced fluorescence ratiometric cyanide sensing in the optical window of tissues and blood, facilitating their use for the transdermal monitoring of cyanide for mammalian safeguard or postmortem in fire victims, both areas of active research. PMID:15755185

  15. 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

  16. Development of output signal-to-noise ratio tester for microchannel plate and fluorescent screen component

    Science.gov (United States)

    Wu, Xinglin; Qiu, Yafeng; Zhou, Jin; Qian, Yunsheng

    The core components of Image intensifier is microchannel plate (MCP) and fluorescent screen component. The present paper deeply studies output signal-to-noise ratio (SNR) characteristics of MCP and fluorescent screen component. A tester system using to the evaluation of characteristics of the output SNR of MCP and fluorescent screen component, consists of a vacuum system, a surface electron source, mechanical mechanism components ,a high-voltage power supply system, a signal processing system, communication interfaces, a data acquisition and control system, computer system, and testing software. a hot cathode used as an electron source, generates a surface electron flow to provide the input signal. A photomultiplier tube is used to detection faceplate output brightness of the light spot. Then, the output SNR of MCP and fluorescent screen component is processed with a combination of methods of the hardware filter and digital filtering software. The output SNR of MCP and fluorescent screen component is measured under different conditions, and the results are analyzed. This test system Provide a technical to promote the image intensifier research, and experience to testing other parameters or in other areas of research.

  17. 竹炭有机肥对有机卷心菜叶绿素荧光特性和相对叶绿素含量的影响%Effect of bamboo charcoal organic fertilizer on chlorophyll fluores-cence characteristics and relative chlorophyll content of organic cab-bage

    Institute of Scientific and Technical Information of China (English)

    马锦丽; 黄鹤凤; 江洪; 舒海燕; 张金梦; 吴丹娜; 孙文文; 吴孟霖; 方成圆; 陈晓峰

    2015-01-01

    Selecting organic cabbage in Chongming of Shanghai dol y farm as the research object, and set up three bamboo charcoal organic fertilizer processing:BC180 (180 kg/20 m × 20 m), BC60 (60 kg/20 m × 20 m), CK (control), During July(Rosette period) and August(Fruit period) in 2014, its chlorophyl fluorescence kinetics parameter and relative chlorophyl content is determined by a random and relative method, in order to analyze the influence of bamboo charcoal organic fertilizer on the organic cabbage.The results showed that different growth period under the same processing, organic cabbage leaf blade light systemⅡ(PSⅡ), initial fluorescence (F0), the largest fluorescence (Fm), maximum photochemical efficiency (Fv/Fm), potential photosynthetic activity (Fv/F0), the actual photochemical efficiency (Yield) were rosette period > fruit period; Apparent photosynthetic electron transport rate (ETR), coefficient of photochemical quenching (qP) and relative chlorophyl content (SPAD) was fruit period>rosette period. The same growth period under different processing, Fv/Fm, Fv/F0, Yield, ETR, qP were increasing as fertilizer rate increasing, NPQ increases during rosette period, and became lower during knot bal period. Different growth period and fertilizer's interaction on Fm, Fv/Fm, Fv/F0, NPQ were very significant (P结球期;表观光合电子传递速率(ETR)、光化学淬灭系数(qP)、相对叶绿素含量(SPAD)为结球期>莲座期。同一生长期不同处理下,Fv/Fm、Fv/F0、Yield、ETR、qP均是随着施肥量增加而增加,NPQ则为莲座期增加,结球期又降低。不同生长期不同施肥量交互作用对Fm、Fv/Fm、Fv/F0、NPQ影响极显著(P<0.01),对qP影响显著(P<0.05)。这说明增施竹炭有机肥对有机卷心菜叶绿素荧光指标和相对叶绿素含量有显著影响,且BC60处理下更有助于其光合固碳,增加产量,符合低碳有机农业宗旨。

  18. Fluorescence signalling of the transition metal ions: Design strategy based on the choice of the fluorophore component

    Indian Academy of Sciences (India)

    N B Sankaran; S Banthia; A Samanta

    2002-12-01

    Transition metal ions are notorious for their fluorescence quenching abilities. In this paper, we discuss the design strategies for the development of efficient off-on fluorescence signalling systems for the transition metal ions. It is shown that even simple fluorophore-spacer-receptor systems can display excellent off-on fluorescence signalling towards the quenching metal ions when the fluorophore component is chosen judiciously.

  19. Fluorescence signaling of Zr4+ by hydrogen peroxide assisted selective desulfurization of thioamide.

    Science.gov (United States)

    Hwang, Jiyoung; Choi, Myung Gil; Eor, Suyoung; Chang, Suk-Kyu

    2012-02-01

    Thioamide derivative with a pyrene fluorophore was smoothly transformed to its corresponding amide by Zr(4+) ions in the presence of hydrogen peroxide. The transformation was evidenced by (1)H NMR spectroscopy and the signaling was completed within 10 min after sample preparation. Interference from Ag(+) and Hg(2+) ions in Zr(4+)-selective fluorescence signaling was readily suppressed with the use of Sn(2+) as a reducing additive. Discrimination of Zr(4+) from closely related hafnium, which is a frequent contaminant in commercial zirconium, was not possible. Prominent Zr(4+)-selective turn-on type fluorescence signaling was possible with a detection limit of 4.6 × 10(-6) M in an aqueous 99% ethanol solution. PMID:22260347

  20. Signal Discrimination Between Fluorescent Proteins in Live Cells by Long-wavelength Optical Modulation.

    Science.gov (United States)

    Jablonski, Amy E; Hsiang, Jung-Cheng; Bagchi, Pritha; Hull, Nathan; Richards, Chris I; Fahrni, Christoph J; Dickson, Robert M

    2012-12-01

    Fluorescent proteins (FPs) have revolutionized molecular and cellular biology; yet, discrimination over cellular autofluorescence, spectral deconvolution, or detection at low concentrations remain challenging problems in many biological applications. By optically depopulating a photoinduced dark state with orange secondary laser co-excitation, the higher-energy green AcGFP fluorescence is dynamically increased. Modulating this secondary laser then modulates the higher-energy, collected fluorescence; enabling its selective detection by removing heterogeneous background from other FPs. Order-of-magnitude reduction in obscuring fluorophore background emission has been achieved in both fixed and live cells. This longwavelength modulation expands the dimensionality to discriminate FP emitters based on dark state lifetimes and enables signal of interest to be recovered by removing heterogeneous background emitter signals. Thus, AcGFP is not only useful for extracting weak signals from systems plagued by high background, but it is a springboard for further FP optimization and utilization for improving sensitivity and selectivity in biological fluorescence imaging. PMID:23419973

  1. 基于叶绿素荧光光谱的生菜硝酸盐含量检测%Detection of nitrate content in lettuce based on chlorophyll fluorescence spectrum

    Institute of Scientific and Technical Information of China (English)

    王琳琳; 于海业; 张蕾; 赵红星

    2016-01-01

    为了寻求生菜叶片硝酸盐含量的快速无损检测方法,该文利用叶绿素荧光光谱分析技术对生菜(Lactuca sativa L.)叶片硝酸盐含量进行检测研究。对比及分析500~550、650~715和715~800 nm 3个波段的叶绿素荧光光谱特征参数与生菜叶片硝酸盐含量的关系,得出650~715 nm 波段的叶绿素荧光光谱特征参数与生菜叶片硝酸盐含量之间线性关系显著,决定系数 R2为0.816,标准误差为0.147,以此建立的回归模型能够很好地反映生菜叶片硝酸盐含量与叶绿素荧光光谱特征参数的关系;将同批进行试验的30个样本作为回归方程的校验集,进行模型验证,预测值与实测值之间决定系数R2为0.752,表明回归模型对生菜叶片硝酸盐含量有良好的预测效果。研究结果为生菜叶片硝酸盐含量的快速无损检测提供参考。%With the development of spectral technology, many researchers have done a lot of research on the nondestructive testing methods of nitrate content in leaves and have achieved some results. However, most of the studies have used visible and near infrared spectroscopy or mid infrared spectroscopy technology, and the chlorophyll fluorescence spectrum technology is still not used. Therefore, this paper used chlorophyll fluorescence spectrum analysis technology to study the relationship between nitrate content and fluorescence spectrum. With aerosol cultured lettuce as the research object, the chlorophyll fluorescence spectrum characteristic parameters were extracted to establish the function relationship between the characteristic parameters of chlorophyll fluorescence spectrum and the nitrate content of lettuce leaves, which laid a theoretical foundation for the rapid and nondestructive detection of nitrate content in lettuce leaves. The peak values of fluorescence intensity of 500-550, 650-715 and 715-800 nm were the characteristic parameters of chlorophyll fluorescence

  2. Influence of UV-B radiation on photosynthetic activity and chlorophyll fluorescence kinetics in Norway spruce (Picea abies (L.) Karst.) seedlings

    International Nuclear Information System (INIS)

    Norway spruce [Picea abies (L.) Karst.] seedlings were grown in greenhouses with two supplemental levels of ultraviolet-B (UV-B) radiation. Photochemical efficiency of photosystem II and vitality index were determined monthly. At the end of the experiment, growth, chlorophyll content and photosynthetic rates were measured. The data indicate that low temperature in winter affected light dependent processes in experimental plants including control, while the rise of ambient temperatures, moderate this effect. The synergistic effects of UV-B radiation and low temperatures could only be observed in the second winter period. Measurements of net photosynthetic activity in the second winter period showed significant differences between treated and untreated plants. (author)

  3. Larval vision contributes to gregarious settlement in barnacles: adult red fluorescence as a possible visual signal

    KAUST Repository

    Matsumura, K.

    2014-02-26

    Gregarious settlement, an essential behavior for many barnacle species that can only reproduce by mating with a nearby barnacle, has long been thought to rely on larval ability to recognize chemical signals from conspecifics during settlement. However, the cyprid, the settlement stage larva in barnacles, has one pair of compound eyes that appear only at the late nauplius VI and cyprid stages, but the function(s) of these eyes remains unknown. Here we show that cyprids of the intertidal barnacle Balanus (=Amphibalanus) amphitrite can locate adult barnacles even in the absence of chemical cues, and prefer to settle around them probably via larval sense of vision. We also show that the cyprids can discriminate color and preferred to settle on red surfaces. Moreover, we found that shells of adult B. amphitrite emit red auto-fluorescence and the adult extracts with the fluorescence as a visual signal attracted cyprid larvae to settle around it. We propose that the perception of specific visual signals can be involved in behavior of zooplankton including marine invertebrate larvae, and that barnacle auto-fluorescence may be a specific signal involved in gregarious larval settlement.

  4. [Rapid and high throughput measurement of lipase thermo-stability through ANS fluorescence signal assay].

    Science.gov (United States)

    Feng, Weizong; Lin, Junhan; Cai, Shaoli; Zou, Youtu; Chen, Guoren; Huang, Ping; Lin, Yajing; Wang, Bingbing; Lin, Lin

    2011-04-01

    We have developed a rapid and high throughput lipase-ANS (8-Anilino-l-naphthalenesulfonic acid) assay to evaluate the thermo-stability of lipases based on the ANS fluorescence signal's increasing and shifting when this small fluorescence probes binds to lipase. The testing lipase samples were incubated at a temperature range of 25 degrees C to 65 degrees C for 30 min before mixed with ANS solution (0.20 mg/mL lipase and 0.05 mmol/L ANS in the buffer of 20 mmol/L Tris-HCl, 100 mmol/L NaCl, pH 7.2) in a cuvette or microplate. Fluorescence signals of the samples were measured at EX 378 nm, EM 465 nm with a fluorescence photometer or a plate reader, and Tm was calculated with the software of GraphPad Prism5.0. The Tm values of several mutants of Penicillium expansum lipase (PEL) were measured with this ANS assay and conventional method simultaneously and the results show that Tm values are comparative and consistent between these methods, suggesting that the lipase-ANS assay is a reliable, rapid and high throughput method for lipase thermo-stability measurement. PMID:21847993

  5. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-01-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  6. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-02-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  7. 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.

  8. Beyond "turn-on" readout: from zero background to signal amplification by combination of magnetic separation and plasmon enhanced fluorescence.

    Science.gov (United States)

    Gong, Suqin; Xia, Yunsheng

    2016-08-11

    By magnetic separation and subsequent plasmon enhanced fluorescence, an assay platform with a signal output from completely "zero" background to fluorescence amplification is achieved, using quantum dots as reporters. So, it well breaks through the conventional "turn-on" strategy in both lower and upper limits. The sensitivity for hyaluronidase sensing is enhanced 10(4)-10(6) times as compared with previous fluorescence methods. PMID:27398675

  9. Photoswitching Near-Infrared Fluorescence from Polymer Nanoparticles Catapults Signals over the Region of Noises and Interferences for Enhanced Sensitivity.

    Science.gov (United States)

    Wang, Jie; Lv, Yanlin; Wan, Wei; Wang, Xuefei; Li, Alexander D Q; Tian, Zhiyuan

    2016-02-24

    As a very sensitive technique, photoswitchable fluorescence not only gains ultrasensitivity but also imparts many novel and unexpected applications. Applications of near-infrared (NIR) fluorescence have demonstrated low background noises, high tissue-penetrating ability, and an ability to reduce photodamage to live cells. Because of these desired features, NIR-fluorescent dyes have been the premium among fluorescent dyes, and probes with photoswitchable NIR fluorescence are even more desirable for enhanced signal quality in the emerging optical imaging modalities but rarely used because they are extremely challenging to design and construct. Using a spiropyran derivative functioning as both a photoswitch and a fluorophore to launch its periodically modulated red fluorescence excitation energy into a NIR acceptor, we fabricated core-shell polymer nanoparticles exhibiting a photoswitchable fluorescence signal within the biological window (∼700-1000 nm) with a peak maximum of 776 nm. Live cells constantly synthesize new molecules, including fluorescent molecules, and also endocytose exogenous particles, including fluorescent particles. Upon excitation at different wavelengths, these fluorescent species bring about background noises and interferences covering nearly the whole visible region and therefore render many intracellular targets unaddressable. The oscillating NIR fluorescence signal with an on/off ratio of up to 67 that the polymer nanoparticles display is beyond the typical background noises and interferences, thus producing superior sharpness, reliability, and signal-to-noise ratios in cellular imaging. Taking these salient features, we anticipate that these types of nanoparticles will be useful for in vivo imaging of biological tissue and other complex specimens, where two-photon activation and excitation are used in combination with NIR-fluorescence photoswitching. PMID:26859429

  10. 叶绿素荧光技术在珊瑚礁研究中的应用%Application of Chlorophyll Fluorescence Technique in the Study of Coral Reefs

    Institute of Scientific and Technical Information of China (English)

    周洁; 施祺; 余克服

    2011-01-01

    Mutualism between corals and their zooxanthellae is the essential feature of reef formation. Through performing photosynthesis, zooxanthellae nourish the host coral as well as help it deposit its skeleton. Thus, the chlorophyll fluorescence technique, previously being used in the study of photosynthesis of plants, including algae, can shed light on the research of coral reefs, and has been widely spread in the field. Its application contains several aspects: revealing of photophysiology principles of symbiont dinoflagelates, explanation of the machanism of coral bleaching, early warning of coral bleaching, monitoring the responses of coral to pollutions, monitoring the effects of turbidity to coral growth, and exploring the ecological pattern of coral reef. PAM fluorometry has good potential for such applications, as fluorescence yield is a sensitive, non-invasive indicator of sublethal stress. Therefore, the study of physiological ecology of scleractinian corals may be more effective in the aid of chlorophyll fluorescence technique.%珊瑚礁生态系统最基本的生态特征是虫黄藻与珊瑚虫的共生,虫黄藻的光合作用在珊瑚礁生态系统中发挥着重要作用,因此用于测定植物光合作用的叶绿素荧光技术在认识珊瑚礁生态系统中得到越来越广泛的应用.应用方面主要包括:①揭示珊瑚共生藻光生理学原理;②探索珊瑚白化的机制;③监测及预警珊瑚白化事件;④研究珊瑚对污染的响应;⑤监测珊瑚对水体浑浊的响应;⑥探寻珊瑚礁生态模式.叶绿素荧光技术具有快速、灵敏和非破坏性测量等优点,在造礁珊瑚生理生态研究方面将有广阔的应用前景.

  11. Detection and Quantification of Heme and Chlorophyll Precursors Using a High Performance Liquid Chromatography (HPLC) System Equipped with Two Fluorescence Detectors

    Czech Academy of Sciences Publication Activity Database

    Pilný, Jan; Kopečná, Jana; Noda, J. A.; Sobotka, Roman

    2015-01-01

    Roč. 5, č. 3 (2015), s. 1-5. ISSN 2331-8325 R&D Projects: GA MŠk EE2.3.30.0059; GA MŠk ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : fluorescence detector Subject RIV: EE - Microbiology, Virology

  12. In vitro complexes of copper and zinc with chlorophyll

    OpenAIRE

    JELENA PETROVIC; GORAN NIKOLIC; DEJAN MARKOVIC

    2006-01-01

    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 allome...

  13. 增强UV-B辐射对水稻叶绿素荧光特性的影响%Influence of Enhanced UV-B Radiation on Chlorophyll Fluorescence Characteristics of Rice

    Institute of Scientific and Technical Information of China (English)

    乔媛; 殷红; 李虎; 杨振兴; 高敏

    2014-01-01

    以沈农265水稻为试材,自然光为对照,研究了2种增强紫外辐射处理下(分别增加5%和10%),水稻不同生育时期光合色素含量和叶绿素荧光动力学参数的变化特征。研究结果显示,两处理下的叶绿素含量在拔节期减少最多,叶绿素a分别下降13.87%和23.30%,叶绿素b分别下降10.76%和17.70%;而类胡萝卜素含量均有所增加,其中抽穗期增幅最大,分别比对照增加了21.55%和31.02%。2种处理下的PSⅡ原初光能转换效率( Fv/Fm )在灌浆期下降最多,分别比对照下降了4.4%和7.83%;PSⅡ潜在活性(Fv/Fo)也比对照降低了9.02%和17.03%;实际量子产量(ΦPSⅡ)在抽穗期降幅较大,但处理间差异不显著(P<0.05);2种处理下的光化学荧光淬灭系数(qP)均有所降低,且降幅随生育进程逐渐减小;2种处理下的非光化学荧光淬灭( NPQ)在各生育时期的变化截然相反,分别比对照升高和降低。%It was used to investigate the contents of photosynthetic pigment and the characteristics of chloro-phyll fluorescence kinetics parameters in the different growth stages of rice ( Shennong 265 ) at different treatments (UV radiation intensity increased by 5% and 10% respectively),compared with natural lighting. Results showed that the contents of chlorophyll-a and chlorophyll-b were diminished significantly in the jointing stage. The content of chlorophyll-a was diminished by 13. 87% and 23. 30% respectively. The content of chlorophyll-b was diminished by 10. 76% and 17. 70% respectively. The contents of carotenoids were increased by 21. 55% and 31. 02% respec-tively,especially in the heading stage. The intrinsic photochemical efficiency (Fv/Fm) of two treatments was dimin-ished by 4. 4% and 7. 83% respectively in the filling stage,and the potential activities (Fv/Fo) were diminished by 9. 02% and 17. 03% respectively. Decreasing amplitude of effective quantum yield (ΦPSⅡ) in the heading stage was

  14. 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.

  15. 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.

  16. Determining Photosynthetic Parameters from Leaf CO2 Exchange and Chlorophyll Fluorescence (Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Specificity Factor, Dark Respiration in the Light, Excitation Distribution between Photosystems, Alternative Electron Transport Rate, and Mesophyll Diffusion Resistance.

    Science.gov (United States)

    Laisk, A.; Loreto, F.

    1996-03-01

    Using simultaneous measurements of leaf gas exchange and chlorophyll fluorescence, we determined the excitation partitioning to photosystem II (PSII), the CO2/O2 specificity of ribulose-1,5-bisphosphate carboxylase/oxygenase, the dark respiration in the light, and the alternative electron transport rate to acceptors other than bisphosphoglycerate, and the transport resistance for CO2 in the mesophyll cells for individual leaves of herbaceous and tree species. The specificity of ribulose-1,5-bisphosphate carboxylase/oxygenase for CO2 was determined from the slope of the O2 dependence of the CO2 compensation point between 1.5 and 21% O2. Its value, on the basis of dissolved CO2 and O2 concentrations at 25.5[deg]C, varied between 86 and 89. Dark respiration in the light, estimated from the difference between the CO2 compensation point and the CO2 photocompensation point, was about 20 to 50% of the respiration rate in the dark. The excitation distribution to PSII was estimated from the extrapolation of the dependence of the PSII quantum yield on F/Fm to F = 0, where F is steady-state and Fm is pulse-satuarated fluorescence, and varied between 0.45 and 0.6. The alternative electron transport rate was found as the difference between the electron transport rates calculated from fluorescence and from gas exchange, and at low CO2 concentrations and 10 to 21% O2, it was 25 to 30% of the maximum electron transport. The calculated mesophyll diffusion resistance accounted for about 20 to 30% of the total mesophyll resistance, which also includes carboxylation resistance. Whole-leaf photosynthesis is limited by gas phase, mesophyll diffusion, and carboxylation resistances in nearly the same proportion in both herbaceous species and trees. PMID:12226229

  17. 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 seed coat

  18. Recognition- and reactivity-based fluorescent probes for studying transition metal signaling in living systems.

    Science.gov (United States)

    Aron, Allegra T; Ramos-Torres, Karla M; Cotruvo, Joseph A; Chang, Christopher J

    2015-08-18

    Metals are essential for life, playing critical roles in all aspects of the central dogma of biology (e.g., the transcription and translation of nucleic acids and synthesis of proteins). Redox-inactive alkali, alkaline earth, and transition metals such as sodium, potassium, calcium, and zinc are widely recognized as dynamic signals, whereas redox-active transition metals such as copper and iron are traditionally thought of as sequestered by protein ligands, including as static enzyme cofactors, in part because of their potential to trigger oxidative stress and damage via Fenton chemistry. Metals in biology can be broadly categorized into two pools: static and labile. In the former, proteins and other macromolecules tightly bind metals; in the latter, metals are bound relatively weakly to cellular ligands, including proteins and low molecular weight ligands. Fluorescent probes can be useful tools for studying the roles of transition metals in their labile forms. Probes for imaging transition metal dynamics in living systems must meet several stringent criteria. In addition to exhibiting desirable photophysical properties and biocompatibility, they must be selective and show a fluorescence turn-on response to the metal of interest. To meet this challenge, we have pursued two general strategies for metal detection, termed "recognition" and "reactivity". Our design of transition metal probes makes use of a recognition-based approach for copper and nickel and a reactivity-based approach for cobalt and iron. This Account summarizes progress in our laboratory on both the development and application of fluorescent probes to identify and study the signaling roles of transition metals in biology. In conjunction with complementary methods for direct metal detection and genetic and/or pharmacological manipulations, fluorescent probes for transition metals have helped reveal a number of principles underlying transition metal dynamics. In this Account, we give three recent

  19. A fast responsive two-photon fluorescent probe for imaging H₂O₂ in lysosomes with a large turn-on fluorescence signal.

    Science.gov (United States)

    Ren, Mingguang; Deng, Beibei; Wang, Jian-Yong; Kong, Xiuqi; Liu, Zhan-Rong; Zhou, Kai; He, Longwei; Lin, Weiying

    2016-05-15

    Hydrogen peroxide (H2O2) plays a crucial role in many biological processes in the human body. As our understanding of the complexity of physiological H2O2 in lysosome, investigative tools are required to make sense of this interconnectivity. Toward this goal, we have developed a new example of a fast responsive and lysosome-targeted two-photon H2O2 fluorescent probe (Lyso-HP) with a large turn-on fluorescence signal (80-fold fluorescence enhancement). The addition of H2O2 to Lyso-HP results a dramatic fluorescence enhancement around 550 nm. The probe could image exogenous and endogenous H2O2 in living cells and the probe was located in lysosomes with high colocalization coefficient (0.96) compared with LysoTracker. The large fluorescence enhancement of the two-photon probe Lyso-HP renders it attractive for imaging H2O2 in living tissues with deep tissue penetration. Significantly, the probe is feasible for fluorescently monitoring H2O2 level changes in lysosomes and suitable for fluorescence imaging of H2O2 in living tissues with deep penetration by using two-photon microscopy. PMID:26710341

  20. Fluorescence signals of core-shell quantum dots enhanced by single crystalline gold caps on silicon nanowires

    International Nuclear Information System (INIS)

    We use nanoscale (20-300 nm in diameter) single crystalline gold (Au)-caps on silicon nanowires (NWs) grown by the vapor-liquid-solid (VLS) growth mechanism to enhance the fluorescence photoluminescence (PL) signals of highly dilute core/shell CdSeTe/ZnS quantum dots (QDs) in aqueous solution (10-5 M). For NWs without Au-caps, as they appear, for example, after Au etching in aqua regia or buffered KI/I2-solution, essentially no fluorescence signal of the same diluted QDs could be observed. Fluorescence PL signals were measured using excitation with a laser wavelength of 633 nm. The signal enhancement by single crystalline, nanoscale Au-caps is discussed and interpreted based on finite element modeling (FEM).

  1. Acquisition and reconstruction of Raman and fluorescence signals for rat leg imaging

    Science.gov (United States)

    Demers, Jennifer-Lynn; Pogue, Brian; Leblond, Frederic; Esmonde-White, Francis; Okagbare, Paul; Morris, Michael

    2011-03-01

    Recovery of Raman or Fluorescence signatures from within thin tissues benefits from model-based estimation of where the signal came from, especially if the signal passes through layers in which the absorption or scattering signatures distort the signal. Estimation of the signal strength requires appropriate normalization or model-based recovery, but the key to achieving good results is a good model of light transport. While diffusion models are routinely used for optical tomography of tissue, there's some thought that more precise radiation transport modeling is required for accurate estimation. However, diffusion is often used for small animal imaging, because it's a practical approach, which doesn't require knowledge of the scatter phase function at each point in the tissue. The question asked in this study is, whether experimentally acquired data in small volumes such as a rodent leg can be accurately modeled and reconstructed using diffusion theory. This study uses leg geometries extracted from animal CT scans and liquid phantoms to study the diffusion approximations. The preliminary results show that under certain conditions the collected data follows the expected trend.

  2. A dual-color fluorescence-based platform to identify selective inhibitors of Akt signaling.

    Directory of Open Access Journals (Sweden)

    Aranzazú Rosado

    Full Text Available BACKGROUND: Inhibition of Akt signaling is considered one of the most promising therapeutic strategies for many cancers. However, rational target-orientated approaches to cell based drug screens for anti-cancer agents have historically been compromised by the notorious absence of suitable control cells. METHODOLOGY/PRINCIPAL FINDINGS: In order to address this fundamental problem, we have developed BaFiso, a live-cell screening platform to identify specific inhibitors of this pathway. BaFiso relies on the co-culture of isogenic cell lines that have been engineered to sustain interleukin-3 independent survival of the parental Ba/F3 cells, and that are individually tagged with different fluorescent proteins. Whilst in the first of these two lines cell survival in the absence of IL-3 is dependent on the expression of activated Akt, the cells expressing constitutively-activated Stat5 signaling display IL-3 independent growth and survival in an Akt-independent manner. Small molecules can then be screened in these lines to identify inhibitors that rescue IL-3 dependence. CONCLUSIONS/SIGNIFICANCE: BaFiso measures differential cell survival using multiparametric live cell imaging and permits selective inhibitors of Akt signaling to be identified. BaFiso is a platform technology suitable for the identification of small molecule inhibitors of IL-3 mediated survival signaling.

  3. 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).

  4. Measurement of radiative lifetime in atomic samarium using simultaneous detection of laser-induced fluorescence and photoionization signals

    Indian Academy of Sciences (India)

    A C Sahoo; M L Shah; P K Mandal; A K Pulhani; G P Gupta; Vas Dev; B M Suri

    2014-02-01

    In this paper, we report the investigations of lifetime measurement of odd-parity energy level 19009.52 cm-1 of Sm I using simultaneous detection of laser-induced fluorescence and laserinduced photoionization signals employing pump–probe technique. To the best of our knowledge, this is for the first time that the results obtained using laser-induced fluorescence and photoionization techniques have been compared with each other. The obtained results match well with those reported in the literature.

  5. NaCl胁迫对马齿苋离子吸收及荧光特性的影响%Effects of NaCl Stress on the Ion Distribution and Chlorophyll Fluorescence in Portulaca oleracea L.

    Institute of Scientific and Technical Information of China (English)

    丁海荣; 王茂文; 朱小梅; 刘冲; 邢锦城; 赵宝泉; 陈昌乾; 洪立洲

    2012-01-01

    以马齿苋为材料采用温室盆栽法,研究了NaCl胁迫处理对其生长发育、品质积累、离子分布和叶绿素荧光特性的影响.结果表明,马齿苋种子发芽率、幼苗的鲜质量和株高在25~50 mmol/L NaCl胁迫时比对照略有下降,但其随着NaCl浓度的继续增加均显著降低.0~75 mmol/L NaCl处理浓度可提高马齿苋幼苗维生素C含量.盐胁迫影响植物组织的离子分布,Na+浓度持续增加,K+、Ca2+和Mg2浓度下降.NaCl胁迫下,马齿苋幼苗叶片的初始荧光(Fo)、最大荧光(Fm)、PSⅡ潜在光化学效率(Fv/Fo)和PSⅡ实际光化学效率(ΦPSⅡ)均降低.但在0~50 mmol/LNaCl浓度下,各荧光参数与对照差异不显著.可见,NaCl胁迫下,马齿苋产生了光合作用的光抑制伤害.低浓度下,植株能够较多地将光能用于光化学反应,光抑制程度较低,保持了较高的净光合速率,最终明显减轻盐胁迫对植株生长的影响.%Pot experiments were carried out to study the effects of NaCl stress on the growth, quality, ion distribution and chlorophyll fluorescence in Portulaca oleracea L. Eight different concentrations of NaCl were applied ;0, 25,50,75,100,150,200,250 mmol/L. The results showed as follows;The germination rate,plant fresh weights and heights of seedlings had no difference with the control when the concentration of NaCl was 25 -50 mmol/L,but decreased when the NaCl concentration was above 50 mmol/L. When the concentration of NaCl was 0-75 mmol/L, the Vc content of Portulaca oleracea L. increased. Increased treatment of NaCl induces increased of Na + and decreased of K+ , Mg2+ and Ca2+. Minimal fluorescence (Fo) ,maximum fluorescence (Fm) ,PS II potential fluorescence efficiency (Fv/Fo) and PS H actual fluorescence efficiency ( ΦPSⅡ ) all decreased when stressed by NaCl. And at low concentrations NaCl (0-50 mmol/L) stress,the fluorescence parameters changed slightly. So Portulaca oleracea L. was injured by photo

  6. Fluorescence-enhancement with different ionic inputs in a cryptand-based multi-receptor signalling system

    Indian Academy of Sciences (India)

    Bamaprasad Bag; Parimal K Bharadwaj

    2005-03-01

    Two molecules of a laterally non-symmetric aza cryptand have been attached to 9,10-dimethylanthracene to obtain a multi-receptor fluorescent signalling system in the ``receptor-spacer-fluorophore- spacer-receptor” format. In the absence of a metal ion, weak fluorescence is observed upon excitation of the anthryl group owing to efficient photo-induced electron transfer (PET) of the lone pair of N attached to the anthryl group. However, when a metal salt is added, the lone pair is engaged, thus in blocking of the PET and leading to recovery of fluorescence to different extents depending upon the nature of the metal ion.

  7. Remote sensing vegetation status by laser-induced fluorescence

    International Nuclear Information System (INIS)

    In November 1989 the EUREKA project LASFLEUR (EU 380) started as an European research effort to investigate the future application of far-field laser-induced plant fluorescence for synoptic, airborne environmental monitoring of vegetation. This report includes a brief introduction in a theoretically approach for the laser-induced fluorescence signals of leaves and their spectral and radiometric behaviour. In addition, a detailed description of the design and realization of the second generation of the far-field fluorescence lidar (DLidaR-2) is given with special regard to the optical and electronical setup, followed by a short explanation of the data processing. The main objectives of the far field measurements are to demonstrate the link between laser-induced fluorescence data and plant physiology and to show the reliability of remote single shot lidar measurements. The data sets include the typical daily cycles of the fluorescence for different global irradiation. As expected from biophysical models, the remotely sensed chlorophyll fluorescence is highly correlated with the carbon fixation rate, while the fluorescence ratio F685 / F730 is only dependent on the chlorophyll concentration. Drought stress measurement of evergreen oaks Quercus pubescens confirm the findings of healthy plants with regard to the fluorescence ratio F685 / F730 while the fluorescence signals of stressed plants show a different behavior than nonstressed plants. Additionally, the corresponding physiological data (porometer and PAM data) are presented. (author)

  8. Chlorophyll Degradation in Horticultural Crops

    OpenAIRE

    Kaewsuksaeng, Samak

    2011-01-01

    One of the symptoms of senescence in harvested horticultural crops is the loss of greenness that comes with the degradation of chlorophyll. With senescence, the chlorophyll-degrading enzyme activities such as chlorophyllase, Mg-dechelatase or Mg-dechelation activity, a new chlorophyll-degrading enzyme, pheophytinase, pheophorbidase and chlorophyll-degrading peroxidase, which are involved in chlorophyll degradation, affected greatly in stored horticultural crops. The chlorophyll derivatives, e...

  9. Amplification of the Signal Intensity of Fluorescence-Based Fiber-Optic Biosensors Using a Fabry-Perot Resonator Structure

    Directory of Open Access Journals (Sweden)

    Meng-Chang Hsieh

    2015-02-01

    Full Text Available Fluorescent biosensors have been widely used in biomedical applications. To amplify the intensity of fluorescence signals, this study developed a novel structure for an evanescent wave fiber-optic biosensor by using a Fabry-Perot resonator structure. An excitation light was coupled into the optical fiber through a laser-drilled hole on the proximal end of the resonator. After entering the resonator, the excitation light was reflected back and forth inside the resonator, thereby amplifying the intensity of the light in the fiber. Subsequently, the light was used to excite the fluorescent molecules in the reactive region of the sensor. The experimental results showed that the biosensor signal was amplified eight-fold when the resonator reflector was formed using a 92% reflective coating. Furthermore, in a simulation, the biosensor signal could be amplified 20-fold by using a 99% reflector.

  10. Investigation of signal-to-noise ratio in frequency-domain multiphoton fluorescence lifetime imaging microscopy.

    Science.gov (United States)

    Zhang, Yide; Khan, Aamir A; Vigil, Genevieve D; Howard, Scott S

    2016-07-01

    Multiphoton microscopy (MPM) combined with fluorescence lifetime imaging microscopy (FLIM) has enabled three-dimensional quantitative molecular microscopy in vivo. The signal-to-noise ratio (SNR), and thus the imaging rate of MPM-FLIM, which is fundamentally limited by the shot noise and fluorescence saturation, has not been quantitatively studied yet. In this paper, we investigate the SNR performance of the frequency-domain (FD) MPM-FLIM with two figures of merit: the photon economy in the limit of shot noise, and the normalized SNR in the limit of saturation. The theoretical results and Monte Carlo simulations find that two-photon FD-FLIM requires 50% fewer photons to achieve the same SNR as conventional one-photon FLIM. We also analytically show that the MPM-FD-FLIM can exploit the DC and higher harmonic components generated by nonlinear optical mixing of the excitation light to improve SNR, reducing the required number of photons by an additional 50%. Finally, the effect of fluorophore saturation on the experimental SNR performance is discussed. PMID:27409702

  11. A signal sequence is sufficient for green fluorescent protein to be routed to regulated secretory granules.

    Science.gov (United States)

    El Meskini, R; Jin, L; Marx, R; Bruzzaniti, A; Lee, J; Emeson, R; Mains, R

    2001-02-01

    To investigate trafficking in neuroendocrine cells, green fluorescent protein (GFP) tags were fused to various portions of the preproneuropeptide Y (NPY) precursor. Two neuroendocrine cell lines, AtT-20 corticotrope tumor cells and PC-12 pheochromocytoma cells, along with primary anterior pituitary cells, were examined. Expression of chimeric constructs did not disrupt trafficking or regulated secretion of endogenous ACTH and prohormone convertase 1 in AtT-20 cells. Western blot and immunocytochemical analyses demonstrated that the chimeric constructs remained intact, as long as the Lys-Arg cleavage site within preproNPY was deleted. GFP was stored in, and released from, regulated granules in cells expressing half of the NPY precursor fused to GFP, and also in cells in which only the signal sequence of preproNPY was fused to GFP. Thus, in neuroendocrine cells, entering the lumen of the secretory pathway is sufficient to target GFP to regulated secretory granules. PMID:11159860

  12. Identification of a functional nuclear export signal in the green fluorescent protein asFP499

    International Nuclear Information System (INIS)

    The green fluorescent protein (GFP) asFP499 from Anemonia sulcata is a distant homologue of the GFP from Aequorea victoria. We cloned the asFP499 gene into a mammalian expression vector and showed that this protein was expressed in the human lymphoblast cell line Ramos RA1 and in the embryonic kidney 293T cell line (HEK 293T). In HEK 293T cells, asFP499 was localized mainly in the cytoplasm, suggesting that the protein was excluded from the nucleus. We identified 194LRMEKLNI201 as a candidate nuclear export signal in asFP499 and mutated the isoleucine at position 201 to an alanine. Unlike the wildtype form, the mutant protein was distributed throughout the cytoplasm and nucleus. This is First report of a GFP that contains a functional NES

  13. Correlation of hemodynamic and fluorescence signals under resting state conditions in mice's barrel field cortex.

    Science.gov (United States)

    Bélanger, Samuel; Oliveira Ferreira de Souza, Bruno; Casanova, Christian; Lesage, Frédéric

    2016-03-11

    Both neurons and astrocytes are known to affect local vascular response in the brain following neuronal activity. In order to differentiate the contributions of each cell type to the hemodynamic response during stimulation and resting state, intrinsic optical signal (IOI) was recorded synchronized with fluorescence imaging of calcium concentration sensitive dye Oregon Green BAPTA-1 AM. By changing the stimulation parameters (frequency and duration), it was possible to individually promote neuronal and glial responses and to compare them to levels of oxy (HbO), deoxy (HbR) and total (HbT) hemoglobin concentrations. Finally, resting state recordings were done to investigate the possible correlation between hemoglobin fluctuation and calcium transients, based on different frequency bands associated either with neuronal or glial activity. PMID:26850574

  14. Photochemical reactions of chlorophyll in dehydrated photosystem II: two chlorophyll forms (680 and 700 nm).

    Science.gov (United States)

    Heber, Ulrich; Shuvalov, Vladimir A

    2005-06-01

    Lichens and phototolerant poikilohydric mosses differ from spinach leaves, fern fronds or photosensitive mosses in that they show strongly decreased Fo chlorophyll fluorescence after drying. This desiccation-induced fluorescence loss is rapidly reversible under rehydration. Fluorescence emission from Photosystem II at 685 nm was decreased more strongly by dehydration than 720 nm emission. Reaction centers of Photosystem II lose activity on dehydration and regain it on hydration. Heating of desiccated lichens increased Fo chlorophyll fluorescence. The activation energy for the reversible part of the temperature-dependent fluorescence increase was 0.045 eV, which corresponds to the energy difference between the 680 and 697 nm absorption bands. In desiccated chlorolichens such as Parmelia sulcata, heating induces the appearance of positive variable fluorescence related to the reversible reduction of QA due to overcoming the energy barrier. This is interpreted to provide information on the mechanism of photoprotection: energy is dissipated by changing Chl680 or P680 into a chlorophyll form, which absorbs at 700 nm and emits light at 720 nm (Chl-720 or P680(700)) with a low quantum yield. Dissipation of light energy in this trap is activated by desiccation. PMID:16049759

  15. Small molecule aptamer assays based on fluorescence anisotropy signal-enhancer oligonucleotides.

    Science.gov (United States)

    Perrier, Sandrine; Bouilloud, Prisca; De Oliveira Coelho, Gisella; Henry, Mickael; Peyrin, Eric

    2016-08-15

    Herein, we design novel fluorescence anisotropy (FA) aptamer sensing platforms dedicated to small molecule detection. The assay strategy relied on enhanced fluctuations of segmental motion dynamics of the aptamer tracer mediated by an unlabelled, partially complementary oligonucleotide. The signal-enhancer oligonucleotide (SEO) essentially served as a free probe fraction revealer. By targeting specific regions of the signalling functional nucleic acid, the SEO binding to the unbound aptamer triggered perturbations of both the internal DNA flexibility and the localized dye environment upon the free probe to duplex structure transition. This potentiating effect determined increased FA variations between the duplex and target bound states of the aptameric probe. FA assay responses were obtained with both pre-structured (adenosine) and unstructured (tyrosinamide) aptamers and with dyes of different photochemical properties (fluorescein and texas red). The multiplexed analysis ability was further demonstrated through the simultaneous multicolour detection of the two small targets. The FA method appears to be especially simple, sensitive and widely applicable. PMID:27085946

  16. 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...

  17. 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...

  18. Chlorophyll: The wonder pigment

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.R.

    juice or grow our own sprouts, instead we try to get the benefits of green foods through capsules, tablets or powder of dehydrated or freeze dried forms of wheat grass, blue green algae, or different cereal grasses. Chlorophyll or its derivative... vegetables rich in micronutrients are spinach, drum stick leaves, lettuce, cucumber, beans and green peas. SCIENCE REPORTER, July 2005 31 Feature Article Chlorophyll in Algae Amazingly, some freshwater and marine algae, yet to find place in our daily diet...

  19. Use of a Novel Rover-mounted Fluorescence Imager and Fluorescent Probes to Detect Biological Material in the Atacama Desert in Daylight

    Science.gov (United States)

    Weinstein, S.; Pane, D.; Warren-Rhodes, K.; Cockell, C.; Ernst, L. A.; Minkley, E.; Fisher, G.; Emani, S.; Wettergreen, D. S.; Wagner, M.

    2005-01-01

    We have developed an imaging system, the Fluorescence Imager (FI), for detecting fluorescence signals from sparse microorganisms and biofilms during autonomous rover exploration. The fluorescence signals arise both from naturally occurring chromophores, such as chlorophyll of cyanobacteria and lichens, and from fluorescent probes applied to soil and rocks. Daylight imaging has been accomplished by a novel use of a high-powered flashlamp synchronized to a CCD camera. The fluorescent probes are cell permanent stains that have extremely low intrinsic fluorescence (quantum yields less than 0.01) and a large fluorescence enhancement (quantum yields greater than 0.4) when bound to the target. Each probe specifically targets either carbohydrates, proteins, nucleic acids or membrane lipids, the four classes of macromolecules found in terrestrial life. The intent of the probes is to interrogate the environment for surface and endolithic life forms.

  20. Chlorophyll Fluorescence Characteristic of Ten Bamboo Species of Bambusa in Coastal Sandy Area%滨海沙地簕竹属10个竹种叶绿素荧光特性研究

    Institute of Scientific and Technical Information of China (English)

    涂志华; 潘瑞; 洪雪沿; 荣俊冬; 陈礼光; 郑郁善

    2012-01-01

    通过利用叶绿素荧光测定技术测定滨海沙地簕竹属10个竹种的叶绿素荧光参数试验研究,结果表明:(1)鼓节竹、观音竹、凤尾竹的初始荧光(Fo)、可变荧光(Fv)、最大荧光(Fm)值较高于其它竹种;(2)河边竹、观音竹、青皮竹、青竿竹的PSⅡ最大光化学效率(Fv/Fm)、PSⅡ的潜在活性(Fv/Fo)、PS Ⅱ实际光化学效率(QY)、PSⅡ电子传递量子产率(ΦPSⅡ)等值均高于其它竹种;(3)河边竹、花孝顺竹、破蔑黄竹、青竿竹的光化学猝灭系数(Qp)相对较高;(4)河边竹、青皮竹、青竿竹、鼓节竹的非光化学猝灭系数(NPQ)值相对较低.综上可以看出簕竹属中河边竹、观音竹、青皮竹、青竿竹具有较好的光合生理功能,可作为沿海沙地竹子引种的优选竹种.%Chlorophyll fluorescence parameters of ten bamboo species of Bambusa in the coastal sandy area, i. e. B. tuldoides Munro, B. multiplex cv. Fernleaf, B. mutiplex var. riviereorum R. Maire, B. tuldoides cv. Swolleninternode,B. contracta,B. textilis,B. multiplex var. strigosa, B. ventricosa, B. multiplex cv. alphonse-karr and B. vulgaris cv. vittata, were measured. The results showed that the minimal fluorescence ( Fo) , the variable fluorescence (Fv) , the maximal fluorescence (Fm)of B. tuldoides cv. Swolleninternode, B. mutiplex var. riviereorum R. Maire and B. multiplex cv. Fernleaf were higher than the other species. The PS II maximal photochemical efficiency ( Fv/Fm) , the PSⅡpotential photochemical efficiency ( Fv/ Fo) , the PS II actual photochemical efficiency ( QY ) , and the PS Ⅱ quantum yield of linear electron (ΦPS Ⅱ ) of B. multiplex var. strigosa, B. mutiplex var. riviereorum R. Maire, B. textilis McClure, B. tuldoides Munro were higher than the other species. The photochemical quenching coefficient ( Qp ) of B. multiplex var. strigosa , B. multiplex cv. Alphonse-Karr, B. contracta and B. tuldoides Munro were higher than the other species. The

  1. Dopamine Receptor Signaling in MIN6 β-Cells Revealed by Fluorescence Fluctuation Spectroscopy.

    Science.gov (United States)

    Caldwell, Brittany; Ustione, Alessandro; Piston, David W

    2016-08-01

    Insulin secretion defects are central to the development of type II diabetes mellitus. Glucose stimulation of insulin secretion has been extensively studied, but its regulation by other stimuli such as incretins and neurotransmitters is not as well understood. We investigated the mechanisms underlying the inhibition of insulin secretion by dopamine, which is synthesized in pancreatic β-cells from circulating L-dopa. Previous research has shown that this inhibition is mediated primarily by activation of the dopamine receptor D3 subtype (DRD3), even though both DRD2 and DRD3 are expressed in β-cells. To understand this dichotomy, we investigated the dynamic interactions between the dopamine receptor subtypes and their G-proteins using two-color fluorescence fluctuation spectroscopy (FFS) of mouse MIN6 β-cells. We show that proper membrane localization of exogenous G-proteins depends on both the Gβ and Gγ subunits being overexpressed in the cell. Triple transfections of the dopamine receptor subtype and Gβ and Gγ subunits, each labeled with a different-colored fluorescent protein (FP), yielded plasma membrane expression of all three FPs and permitted an FFS evaluation of interactions between the dopamine receptors and the Gβγ complex. Upon dopamine stimulation, we measured a significant decrease in interactions between DRD3 and the Gβγ complex, which is consistent with receptor activation. In contrast, dopamine stimulation did not cause significant changes in the interactions between DRD2 and the Gβγ complex. These results demonstrate that two-color FFS is a powerful tool for measuring dynamic protein interactions in living cells, and show that preferential DRD3 signaling in β-cells occurs at the level of G-protein release. PMID:27508444

  2. Marine fluorescence from high spectrally resolved satellite measurements

    Science.gov (United States)

    Wolanin, Aleksandra; Dinter, Tilman; Rozanov, Vladimir; Noël, Stefan; Vountas, Marco; Burrows, John P.; Bracher, Astrid

    2014-05-01

    ). Based on the simulated data, we also calculated corrections the influence of for water vapor, Raman scattering and solar zenith angle on the retrieved fluorescence emissions. Our fluorescence results from SCIAMACHY and GOME-2 show similar spatial patterns when compared to the MODIS FLH. The fluorescence is generally stronger in areas of high chlorophyll concentration. The observed differences between SCIAMACHY and GOME-2 DOAS FLH and MODIS FLH arise from differences among instruments, retrieval methods, spatial and temporal sampling and overpass time. Our hyperspectral retrieval shows noisier results than MODIS FLH, but is not susceptible to certain problems as the multispectral FLH, which arise from backscattered light by particulate matter or phycocyanin fluorescence (Abbott and Letelier, 1999). For our fluorescence retrieval, we acquired better quality for the SCIAMACHY data than for GOME-2, due to the higher spectral resolution and the smaller size of the footprint. Our results demonstrate that it is feasible to detect the weak fluorescence signal from the oceans within hyperspectral data from satellite measurements. The method presented is generic and can be applied to other instruments in the future.

  3. 桑沟湾常见温带海草叶绿素荧光特性的比较%Chlorophyll fluorescence characteristics of common temperate seagrass species in Sanggou Bay

    Institute of Scientific and Technical Information of China (English)

    唐望; 方建光; 高亚平; 邹健; 吴桃; 杜美荣

    2012-01-01

    The chlorophyll fluorescence of the blades of three common seagrass species (Zostera marina, Z. caespitosa and Phyllospadix iwatensis) in eastern waters of Chudao, south coast of Sanggou Bay, was determined using the pulse amplitude modulated (PAM) fluo-rometer. The absorbance factor (AF) of seagrass blades were also determined,and the absolute electron transport rates of the seagrass species were calculated. It was found that the photosyn-thetic activity of Z. marina, Z. caespitosa and P. iwatensis, was strongly influenced by leaf age. The chlorophyll content and the AF values increased with blade age in respective plants. Young blades showed higher electron transport rate than older ones (Zm: Leaf 1 = 26. 56, Leaf 2 = 16.3, Leaf 3= 19.98; Pi: Leaf 1 =22.31, Leaf 2=19. 23, Leaf 3 = 17. 06; and Zc: Leaf 1 = 20. 16, Leaf 2 =16. 10,Leaf 3 = 13. 10). Among three species, Z. marina showed the highest photosynthetic activity (ETRmax=22. 67), in accordance with its highest productivity in the field compared with the other two species.%2011年7~8月在桑沟湾楮岛南岸东部海域,利用水下调制脉冲式荧光仪(DIVING-PAM)原位测定了中国北方3种常见温带海草大叶藻、丛生大叶藻以及红纤维虾海藻的不同叶龄叶片的叶绿素荧光特性,并确定了几种海草的吸光系数(AF)和叶片叶绿素含量,计算出海草绝对电子传递速率.实验结果表明,叶龄对海草的光合活性有较大影响,同种海草的AF值和叶绿素含量都随叶龄增加而增加,叶龄小的叶片明显具有较大的最大电子传递速率(ETRmx)(大叶藻∶叶1=26.56,叶2=21.45,叶3=19.98;红纤维虾海藻叶1=22.31,叶2=19.23,叶3=17.06;丛生叶藻∶叶1=20.16,叶2=16.10;叶3=13.10).相比于丛生大叶藻和红纤维虾形藻,大叶藻具有最高的光合活性(ETRmax=22.67),这也与大叶藻在3种海草中所具有最高的初级生产力是相符合的.

  4. An optimised method for correcting quenched fluorescence yield

    Directory of Open Access Journals (Sweden)

    L. Biermann

    2014-05-01

    Full Text Available Under high light intensity, phytoplankton protect their photosystems from bleaching through non-photochemical quenching processes. The consequence of this is suppression of fluorescence emission, which must be corrected when measuring in situ yield with fluorometers. Previously, this has been done using the limit of the mixed layer, assuming that phytoplankton are uniformly mixed from the surface to this depth. However, the assumption of homogeneity is not robust in oceanic regimes that support deep chlorophyll maxima. To account for these features, we correct from the limit of the euphotic zone, defined as the depth at which light is at ~1% of the surface value. This method was applied to fluorescence data collected by eleven animal-borne fluorometers deployed in the Southern Ocean over four austral summers. Six tags returned data showing evidence of deep chlorophyll features. Using the depth of the euphotic layer, quenching was corrected without masking subsurface fluorescence signals.

  5. Quantification of Plant Chlorophyll Content Using Google Glass

    OpenAIRE

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

    2015-01-01

    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 rel...

  6. Interphase fluorescence in situ hybridization signal detection by computing intensity variance along the optical axis

    Science.gov (United States)

    Li, Zheng; Zheng, Bin; Ren, Liqiang; Liu, Hong

    2014-02-01

    Fluorescence in situ Hybridization technology is a commonly used tool to detect chromosome aberrations, which are often pathologically significant. Since manual FISH analysis is a tedious and time-consuming procedure, reliable and robust automated image acquisition and analysis are in demand. Under high magnification objective lenses such as 60x and 100x, the depth of field will often be too small and the FISH probes may not always lie in the same focal plane. A statistical variance based automated FISH analysis method is developed in order to address this problem. On a stack of slices at consecutive image planes with a step size d, the statistical variance alone the z-axis is calculated to form a 2-D matrix. Since pixels shift dramatically to high intensity at FISH probe location, the probes will manifest high peak values in the matrix. A computer-aided detection scheme based on top-hat transform is applied to the matrix to detect FISH probe signals. This study demonstrates a simple and robust method for FISH probe detection as well as a way of 2- D representation of 3-D data.

  7. G-quadruplex − based homogenous fluorescence platform for ultrasensitive DNA detection through isothermal cycling and cascade signal amplification

    International Nuclear Information System (INIS)

    We describe a simple and homogenous fluorimetric method for sensitive determination of DNA. It is based on target-triggered isothermal cycling and a cascade exponential amplification reaction that generates a large amount of a G-quadruplex. This results in strong fluorescence signal when using thioflavin T as a G-quadruplex-specific light-up fluorescent probe. Tedious handling after amplification is widely eliminated by the addition of thioflavin T. No other exogenous reagent is required. This detection platform is inexpensive and rapid, and displays high sensitivity for target DNA, with a detection limit as low as 91 pM. (author)

  8. Lil3 Assembles with Proteins Regulating Chlorophyll Synthesis in Barley.

    Directory of Open Access Journals (Sweden)

    Astrid Mork-Jansson

    Full Text Available The light-harvesting-like (LIL proteins are a family of membrane proteins that share a chlorophyll a/b-binding motif with the major light-harvesting antenna proteins of oxygenic photoautotrophs. LIL proteins have been associated with the regulation of tetrapyrrol biosynthesis, and plant responses to light-stress. Here, it was found in a native PAGE approach that chlorophyllide, and chlorophyllide plus geranylgeraniolpyrophosphate trigger assembly of Lil3 in three chlorine binding fluorescent protein bands, termed F1, F2, and F3. It is shown that light and chlorophyllide trigger accumulation of protochlorophyllide-oxidoreductase, and chlorophyll synthase in band F3. Chlorophyllide and chlorophyll esterified to geranylgeraniol were identified as basis of fluorescence recorded from band F3. A direct interaction between Lil3, CHS and POR was confirmed in a split ubiquitin assay. In the presence of light or chlorophyllide, geranylgeraniolpyrophosphate was shown to trigger a loss of the F3 band and accumulation of Lil3 and geranylgeranyl reductase in F1 and F2. No direct interaction between Lil3 and geranylgeraniolreductase was identified in a split ubiquitin assay; however, accumulation of chlorophyll esterified to phytol in F1 and F2 corroborated the enzymes assembly. Chlorophyll esterified to phytol and the reaction center protein psbD of photosystem II were identified to accumulate together with psb29, and APX in the fluorescent band F2. Data show that Lil3 assembles with proteins regulating chlorophyll synthesis in etioplasts from barley (Hordeum vulgare L..

  9. Temperature-dependency of changes in the relaxation of electrochromic shifts, of chlorophyll fluorescence, and in the levels of mRNA transcripts in detached leaves from Pisum sativum exposed to supplementary UV-B radiation

    International Nuclear Information System (INIS)

    Detached Pisum sativum leaves were used to study temperature-dependent and temperature-independent effects of supplementary UV-B radiation on chloroplast-associated components and properties. Temperature-independent effects were considered to be due to direct physical damage by the UV-B radiation itself, whereas temperature-dependent damage was thought to be a result of UV-B-triggered chemical reactions. Supplementary UV-B radiation caused a lowering in chlorophyll fluorescence (Fv Fm) at both 2 and 22°C (by about 20 and 2%, respectively); it is likely to be caused by direct interaction of UV-B quanta with Photosystem II (PS II), since no additional decrease was seen in Fv Fm when leaves irradiated at 2°C were subsequently incubated in darkness for 4 h at 22°C. However, chilling made PS II more prone to UV-B damage. The development of the UV-B effect on the relaxation of the electrochromic shift (t1), caused by the trans-thylakoid membrane potential, showed a greater temperature dependency which indicates that UV-B induces chemical reactions that in turn cause the damage. Exposure for 4 h to supplementary UV-B radiation led to a 75% decrease in t1 at 22°C, whereas the effect at 2°C was much smaller (<50%), even smaller than the effect of the chilling itself. Leaves which were first exposed to UV-B at 2°C, and then left in the dark for 4 h, displayed an additional 37% drop in t1 if the leaves were held at 22°C during the dark period but only a 12% drop if they were held at 2°C in the darkness. This indicates that the UV-B exposure triggers changes in the thylakoid membrane at 2°C which are not fully manifested at this temperature. The lowering of lhc mRNA levels were 34% compared to the control in leaves UV-B-treated at 22°C for 4 h, but only 11% when exposed at 2°C. Interestingly, the mRNA levels of lhc transcripts were increased at 2°C compared with the corresponding sample held at 22°C under both control and UV-B-supplemented light regimes, e.g. a 2

  10. Centimeter-deep tissue fluorescence microscopic imaging with high signal-to-noise ratio and picomole sensitivity

    CERN Document Server

    Cheng, Bingbing; Wei, Ming-Yuan; Pei, Yanbo; DSouza, Francis; Nguyen, Kytai T; Hong, Yi; Tang, Liping; Yuan, Baohong

    2015-01-01

    Fluorescence microscopic imaging in centimeter-deep tissue has been highly sought-after for many years because much interesting in vivo micro-information, such as microcirculation, tumor angiogenesis, and metastasis, may deeply locate in tissue. In this study, for the first time this goal has been achieved in 3-centimeter deep tissue with high signal-to-noise ratio (SNR) and picomole sensitivity under radiation safety thresholds. These results are demonstrated not only in tissue-mimic phantoms but also in actual tissues, such as porcine muscle, ex vivo mouse liver, ex vivo spleen, and in vivo mouse tissue. These results are achieved based on three unique technologies: excellent near infrared ultrasound-switchable fluorescence (USF) contrast agents, a sensitive USF imaging system, and an effective correlation method. Multiplex USF fluorescence imaging is also achieved. It is useful to simultaneously image multiple targets and observe their interactions. This work opens the door for future studies of centimeter...

  11. A dual-site two-photon fluorescent probe for visualizing lysosomes and tracking lysosomal hydrogen sulfide with two different sets of fluorescence signals in the living cells and mouse liver tissues.

    Science.gov (United States)

    Liu, Yong; Meng, Fangfang; He, Longwei; Liu, Keyin; Lin, Weiying

    2016-05-19

    Herein, we have developed a novel dual-site two-photon fluorescent probe as the first paradigm of the probes, which can concurrently report lysosomes and lysosomal H2S with two different sets of fluorescence signals in the living cells and tissues. PMID:27159054

  12. Single Molecule Detection of H2O2 Mediating Angiogenic Redox Signaling on Fluorescent Single-Walled Carbon Nanotube Array

    OpenAIRE

    Kim, Jong-Ho; Arkalgud, Jyoti R.; Boghossian, Ardemis A; Zhang, Jingqing; Han, Jae-Hee; Reuel, Nigel F.; Ahn, Jin-Ho; Mukhopadhyay, Debabrata; Strano, Michael S.

    2011-01-01

    Reactive oxygen species, specifically hydrogen peroxide (H2O2), activate signal transduction pathways during angiogenesis, and therefore play an important role in physiological development as well as various pathophysiologies. Herein, we utilize a near infrared fluorescent single-walled carbon nanotube (SWNT) sensor array to measure the single molecule efflux of H2O2 from human umbilical vein endothelial cells (HUVEC) in response to angiogenic stimulation. Two angiogenic agents were investiga...

  13. 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.

  14. Cleavable DNA-protein hybrid molecular beacon: A novel efficient signal translator for sensitive fluorescence anisotropy bioassay.

    Science.gov (United States)

    Hu, Pan; Yang, Bin

    2016-01-15

    Due to its unique features such as high sensitivity, homogeneous format, and independence on fluorescent intensity, fluorescence anisotropy (FA) assay has become a hotspot of study in oligonucleotide-based bioassays. However, until now most FA probes require carefully customized structure designs, and thus are neither generalizable for different sensing systems nor effective to obtain sufficient signal response. To address this issue, a cleavable DNA-protein hybrid molecular beacon was successfully engineered for signal amplified FA bioassay, via combining the unique stable structure of molecular beacon and the large molecular mass of streptavidin. Compared with single DNA strand probe or conventional molecular beacon, the DNA-protein hybrid molecular beacon exhibited a much higher FA value, which was potential to obtain high signal-background ratio in sensing process. As proof-of-principle, this novel DNA-protein hybrid molecular beacon was further applied for FA bioassay using DNAzyme-Pb(2+) as a model sensing system. This FA assay approach could selectively detect as low as 0.5nM Pb(2+) in buffer solution, and also be successful for real samples analysis with good recovery values. Compatible with most of oligonucleotide probes' designs and enzyme-based signal amplification strategies, the molecular beacon can serve as a novel signal translator to expand the application prospect of FA technology in various bioassays. PMID:26592607

  15. Study of 660 nm laser-induced photoluminescence of chlorophyll-a and its applications

    International Nuclear Information System (INIS)

    Based on the phenomenon of chlorophyll a photoluminescence, this paper introduces a new method to measure the chlorophyll a content, using 660nm laser diode as a new kind of light source to stimulate fluorescence as well as combining a fiber and spectrum technique. We analyze the characteristics of laser-induced fluorescence spectrum of chlorophyll a and then put forward the new method using two parameters, the relative fluorescence intensity and fluorescence intensity ratio F685/F735, to measure the chlorophyll a content in the water and green leaves respectively. The experimental results indicate that it is completely feasible to give a visual judgment for chlorophyll a content, according to the fluorescence emission spectrum of chlorophyll a. Subsequently, it is verified by three kinds of typical applications. All of these provide a new kind of light source to develop the chlorophyll a fluorometry and further give a technical foundation of on-spot monitoring the chlorophyll a content in the ocean or in green leaves

  16. Time-resolved interaction investigations of carbocyanine dyes and chlorophyll a in solution

    International Nuclear Information System (INIS)

    Using a Nd:YAG laser/streak camera system of 30 ps time resolution the quenching of the fluorescence of the carbocyanine dye ICC by chlorophyll a in methanolic solution was investigated. The fluorescence lifetime of ICC decreased within the chlorophyll concentration range 0 - 9x10-5 mol/l from 170 ps to 135 ps. The observed very effective fluorescence quenching process suggests that the formation of heteroaggregates from ICC and chlorophyll is responsible for the rapid energy transfer. (author)

  17. 外源NO对NaCl胁迫下长春花幼苗生物量和叶绿素荧光的影响%Effects of exogenous nitric oxide on biomass and chlorophyll fluorescence of Catharanthus roseus seedlings under NaCl stress

    Institute of Scientific and Technical Information of China (English)

    胡凡波; 刘玲; 隆小华; 刘兆普

    2011-01-01

    A pot experiment in greenhouse was carried out to study the effects of different concentration exogenous NO donor ( sodium nitroprusside, SNP) on the biomass, chlorophyll content, and chlorophyll fluorescence of Catharanthus roseus seedlings under the stress of 50 mmol NaCl · L-1. Among the treatments with SNP, the seedlings treated with 50 mmol NaCl · L-1+ 0. 1 mmol SNP · L-1 had the highest fresh weight and dry weight, being significantly higher (18. 8% and 13. 9% , respectively) than the control (50 mmol NaCl · L-1). Similar to biomass, the chlorophyll a, chlorophyll b, and carotenoid contents in treatment 50 mmol NaCl · L-1 + 0. 1 mmol SNP · L-1 were the highest, but had no significant differences with the control. The variation trend of chlorophyll a/b was more complicated. Applying 0. 1 mmol · L-1 of SNP had the best effect in mitigating the salt damage to Ps Ⅱ reaction center, which increased the fluorescence ( Fv ) , maximal fluorescence ( Fm ) , light energy transformation efficiency of PS Ⅱ ( Fv/Fm ) , activity potential of PS Ⅱ ( Fv/Fo) , actual photochemical efficiency of PS Ⅱ ( (¢)PSⅡ ) , and photochemical quenching (qp) markedly, and decreased the minimal fluorescence (Fo) and non-photochemical quenching (qN) obviously. To sum up, 0. 1 mmol · L-1 of SNP had the best effect in protecting chlorophyll and PS Ⅱ reaction center against salt damage, and also, could promote the growth of the seedlings and enhance their tolerance to 50 mmol Ⅱ L-1 NaCl stress.%在温室条件下采用盆栽法,研究了50mmol· L-1 NaCl胁迫下5个不同浓度外源NO供体硝普钠(sodium nitroprusside,SNP)对长春花(Catharanthus roseus)幼苗生物量、叶绿素含量和叶绿素荧光的影响.结果表明:(1)鲜重和干重均在S2(50mmol·L-1NaCl+0.1mmol·L-1SNP)处理下达到最高,分别较对照So(50mmol·L-1 NaCl)显著增加18.8%和13.9%.叶绿素a、叶绿素b和类胡萝卜素与生物量相似,均在S2处理下

  18. A two-photon fluorescent probe with a large turn-on signal for imaging hydrogen sulfide in living tissues

    International Nuclear Information System (INIS)

    Highlights: • A two-photon fluorescent probe for sensing H2S was developed. • The probe shows a large turn on signal (120-fold enhancement). • The probe is suitable for fluorescence imaging of H2S in living cells and tissues. • The probe was capable of detecting H2S up to 170 μm depth in live tissues. - Abstract: A two-photon fluorescence turn-on H2S probe GCTPOC–H2S based on a two-photon platform with a large cross-section, GCTPOC, and a sensitive H2S recognition site, dinitrophenyl ether was constructed. The probe GCTPOC–H2S exhibits desirable properties such as high sensitivity, high selectivity, functioning well at physiological pH and low cytotoxicity. In particular, the probe shows a 120-fold enhancement in the presence of Na2S (500 μM), which is larger than the reported two-photon fluorescent H2S probes. The large fluorescence enhancement of the two-photon probe GCTPOC–H2S renders it attractive for imaging H2S in living tissues with deep tissue penetration. Significantly, we have demonstrated that the probe GCTPOC–H2S is suitable for fluorescence imaging of H2S in living tissues with deep penetration by using two-photon microscopy. The further application of the two-photon probe for the investigation of biological functions and pathological roles of H2S in living systems is under progress

  19. 基于叶绿素荧光技术的紫菜光适应特征研究%Light adaptation characteristics of porphyra studied by chlorophyll fluorescence technology

    Institute of Scientific and Technical Information of China (English)

    张涛; 沈宗根; 姚春燕; 陆勤勤; 姜红霞; 朱建一; 许璞

    2011-01-01

    通过水样调制式叶绿素荧光仪,对坛紫菜、条斑紫菜叶状体和丝状体在不同光照条件下叶绿素荧光特性进行研究.结果表明:紫菜叶状体和丝状体实际量子效率在光照处理后逐步下降,且随着处理光强的上升,实际量子效率的下降速率更为明显.快速光曲线初始斜率(α)结果与实际量子效率相似,表明光照时间的延长以及光照强度的升高均引起样品实际光能利用效率的下降.快速光曲线结果也显示样品半饱和光强低于150 μmol/(m2·s),说明紫菜这类海藻偏向较低光强的适应性.随着处理光强的上升,样品Ik值逐步升高,说明紫菜具备适应光强变化的光能调节机制.方差分析结果表明,两种紫菜丝状体实际量子效率、快速光曲线初始斜率(α)和最大相对电子传递速率均因光强的上升而显著降低(P<0.05),叶状体实际量子效率、快速光曲线初始斜率也随光强上升而下降,但最大相对电子传递速率基本维持不变,表明紫菜两个生长世代的藻体对光强具有不同的响应机制.诱导曲线测定结果表明,经强光适应的紫菜叶状体光化学猝灭较高,而非光化学猝灭较低,显示强光处理能够提高叶状体对光强的适应能力.%The chlorophyll fluorescence characteristics of thallus and eonchocelis in both species of Por phyra grown under different light intensities were investigated with Water-PAM chlorophyll fluorometer.Results showed that the effective quantum yield of PSⅡ (Yield) of Porphyra decreased after the treatment, and the effective quantum yield of sample decreased obviously with the increasing of light intensity.Results of the initial slop of rapid light cnrvc (α) are sirnilar with the effective quantum yield of sample,which meant both the time after treatment and the increasing of light intensities Would induce the decreasing of actual light energy use efficieney of Porphyra.lhe minimum saturating

  20. 农药胁迫对生菜叶片叶绿素荧光图像参数的影响%Effects of Pesticides on Chlorophyll Fluorescence Image Parameters of Lettuce Leaves

    Institute of Scientific and Technical Information of China (English)

    孙俊; 宋彩惠; 毛罕平; 金夏明; 方敏; 张梅霞

    2014-01-01

    对生菜(Lactuca sativa)分别均匀喷洒浓度为70、140、280μg/L的杀虫剂氰戊菊酯,以清水为对照,以意大利全年耐抽薹生菜为试材,结果表明,随着农药浓度的增加,光系统Ⅱ的最大光化学效率、实际光化学效率、光化学淬灭系数和相对电子传递速率均下降,非光化学淬灭系数、非调节性能量耗散的量子产额和调节性能量耗散的量子产额上升,综合影响造成光系统Ⅱ的中心活性区域缩小、光合速率下降。另外生菜叶片自身的光化合保护机制能在一定程度上减轻农药的胁迫作用。与对照相比,光系统Ⅱ的实际光化学效率受农药影响最大,喷洒浓度为280μg/L的杀虫剂会对生菜光合作用过程产生持续性的、不可逆转的影响。%The Italy lettuce samples were sprayed evenly with water and pesticide fenvalerate with concentrations of 70,140,280 μg/L to study the adverse effect of pesticide on chlorophyll fluorescence parameters of lettuce leaves.With the increase of concentration of pesticide sprayed on the lettuce leaves,the biggest photosynthetic efficiency of photosystem Ⅱ(Fv/Fm),actual photosynthetic efficiency YI,photochemical quenching coefficient (qP) and relative electron transport rate declined and showed a clear decrease,meanwhile the non-photochemical quenching coefficient (qN),regulatory quantum yield of energy dissipation (Y NPQ) and non-regulatory quantum yield of energy dissipation (Y NO) increased significantly. Because of these disturbances,centre activity area of photosystem Ⅱ and actual photochemical efficiency was reduced. Light protection mechanisms of the lettuce leaves alleviated the impact of pesticides to a certain extent.Compared with control group,the actual photosynthetic efficiency of photosystem Ⅱ was one of the most exposed to effects from pesticide.The influence of 280μg/L pesticides on lettuce photosynthesis was continuous and irreversible.

  1. As clorofilas The chlorophylls

    Directory of Open Access Journals (Sweden)

    Nivia Maria Streit

    2005-06-01

    Full Text Available As clorofilas são pigmentos verdes, comuns em todas as células fotossintéticas. Por sua estrutura química ser instável, são facilmente degradadas, resultando em produtos de decomposição que modificam a percepção e qualidade dos alimentos. Esta revisão trata dos vários fatores que interferem na degradação das clorofilas, como a luz, radiação, calor, ácidos, oxigênio, alteração enzimática e interação com outros pigmentos. Também, outro aspecto a ser abordado é a utilização das clorofilas como corantes, através da formação de complexos que tornam esses pigmentos mais estáveis à decomposição.The Chlorophylls are a common green pigment to all photosynthetic cells. They are easily degraded, because of their unstable chemical structure. Degradation results in products alter the perception and quality of foods. This review discusses the various factors, that interfere on chlorophyll degradation such as light, irradiation, heat, acids, oxygen, enzymatical alteration and the interaction with other pigments. Also, the other topic that was mentioned the utilization of the chlorophylls as dyes through a complex formation that make this pigment more stable to degradation.

  2. Extracting fluorescence signal due to direct excitation of the energy acceptor from quantum dot-based FRET

    International Nuclear Information System (INIS)

    An 'in situ' strategy for extracting the fluorescence signal of dye acceptors due to direct excitation from Qdot-based FRET systems has been reported. The relevant theory model was developed to describe the present strategy. This strategy involves selective control of the quantum yield of Qdot donors 'in situ', not only providing a straightforward approach to qualitatively confirm the FRET-based fluorescence enhancement but also allowing us to quantitatively separate the fluorescence signal of dye acceptors due to direct excitation and FRET enhancement from each other with high precision and convenient procedures. Different from existing method which was commonly used in literatures, our 'in situ' strategy does not involve complicated quantification of the dye acceptors conjugated on the surface of Qdots. Results indicated that the fraction of the emission from the dye acceptors due to FRET process decreases with the increase in the amount of dye acceptors on the Qdot surface. In addition, the relation between the quantum yield of Qdot donors and the FRET enhancement factor of the dye acceptors have also been explored for the first time by the present 'in situ' strategy.

  3. Cell abundance and fluorescence of picoplankton in relation to growth irradiance and nitrogen availability in the red sea

    Science.gov (United States)

    Veldhuis, Marcel J. W.; Kraay, Gijsbert W.

    The vertical distribution and cellular fluorescence characteristics (chlorophyll and phycoerythrin, PE) of picoplankton (cyanobacteria and prochlorophytes) in the southern Red Sea were investigated in relation to physico-chemical properties of the water column. At all stations two subpopulations of Synechococcus sp. (type A and B) co-occurred, with maximal numbers up to 75 000·cm -3. Type B, with dim fluorescence signals, dominated the surface waters whereas type A, with bright fluorescence signals, dominated at greater depth. The divinyl a and b containing Prochlorococcus sp. peaked below the cyanobacteria at the deep chlorophyll maximum (DCM) with maximal cell numbers of 276 000·cm -3. Due to thermal stratification the cellular fluorescence (chlorophyll and phycoerythrin) increased with decreasing growth (PAR) irradiance, in an S-shaped manner, but magnitude and slope for the three picoplankters differed. The Synechococcus sp. type B had only a moderate increase in chlorophyll and phycoerythrin fluorescence signals with depth (3.4 and 6.6 fold, respectively), with values saturating at 3% (L d) of the surface irradiance. The deeper-water type not only possessed much higher values for cellular fluorescence than the B type, but the increase with decreasing light level was also much higer (for chlorophyll by a factor of 11 and PE increased by a factor of 23). In addition, maximal values for these fluorescence signals occurred at an isolume of 1 to 0.5%. These differences in concentrations and responses of the pigment content to the prevailing light climate explain the variation in abundance of both types over the water column. Although the prochlorophytes dominated almost the entire euphotic zone, their adaptation to low light levels was even better than in the two types of cyanobacteria. With depth their increase in chlorophyll fluorescence was similar to that observed in the cyanobacteria (with an increase from surface to bottom of the euphotic zone by a factor

  4. From chlorophyll a towards bacteriochlorophyll a: Excited-state processes of modified pigments

    OpenAIRE

    Teuchner, K.; Stiel, H.; Leupold, D; Katheder, Ingrid; Scheer, Hugo

    1994-01-01

    By means of fluorescence spectroscopy and nonlinear absorption experiments, excited-state processes of the modified pigments [3-acetyl]-chlorophyll a, [31-OH]-bacteriochlorophyll a and [3-vinyl]-bacteriochlorophyll a were investigated and compared with those of chlorophyll a and bacteriochlorophyll a.

  5. Characterization of the latent membrane protein 1 signaling complex of Epstein-Barr virus in the membrane of mammalian cells with bimolecular fluorescence complementation

    OpenAIRE

    Everly David N; Emery Amanda; Talaty Pooja

    2011-01-01

    Abstract Background Bimolecular fluorescence complementation (BiFC) is a novel technique to examine protein-protein interaction through the assembly of fluorescent proteins. In the present study, BiFC was used to study the assembly of the Epstein-Barr virus latent membrane protein 1 (LMP1) signaling complex within the membrane of mammalian cells. LMP1 signaling requires oligomerization, localization to lipid rafts, and association of the cytoplasmic domain to adaptor proteins, such as the tum...

  6. On the influence of dissolved organic-matter on remote-sensing of chlorophyll in the straits of skagerrak and kattegat

    OpenAIRE

    Karabashev, Gs

    1992-01-01

    An experimental techniques to estimate the influence of dissolved organic matter (DOM) on remote sensing of chlorophyll in water has been developed, based on the relationship between fluorescence and absorption of light by a substance. The profiles of fluorescence, chlorophyll content in sea water and estimates of light attenuation in water samples were used in the paper. These data have permitted to calculate the regressions linking fluorescence and light absorption at 450 nm by chlorophyll ...

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

    DEFF Research Database (Denmark)

    Frydenvang, Jens

    trustworthy results 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....

  8. Fluorescent and colorimetric chemosensors for cations based on 1,8-naphthalimide derivatives: design principles and optical signalling mechanisms

    International Nuclear Information System (INIS)

    The application of 1,8-naphthalimide derivatives as the photoactive units for the design of optical chemosensors for metal cations and protons with different mechanisms of analyte binding signal transduction and different receptors is discussed. Examples are given of fluorescent and colorimetric cation chemosensors in which the change of the spectral characteristics of the naphthalimide chromophore upon complex formation is due to switching of photophysical processes of charge transfer, electron transfer, energy transfer or excimer formation. The problems of detection of heavy and transition metal cations as well as development of ratiometric optical probes are discussed. The bibliography includes 170 references

  9. Measurements of excited-state-to-excited-state transition probabilities and photoionization cross-sections using laser-induced fluorescence and photoionization signals

    International Nuclear Information System (INIS)

    Laser-induced photoionization and fluorescence signals were simultaneously observed in atomic samarium using Nd:YAG-pumped dye lasers. Two-color, three-photon photoionization and two-color fluorescence signals were recorded simultaneously as a function of the second-step laser power for two photoionization pathways. The density matrix formalism has been employed to analyze these signals. Two-color laser-induced fluorescence signal depends on the laser powers used for the first and second-step transitions as well as the first and second-step transition probability whereas two-color, three-photon photoionization signal depends on the third-step transition cross-section at the second-step laser wavelength along with the laser powers and transition probability for the first and second-step transitions. Two-color laser-induced fluorescence was used to measure the second-step transition probability. The second-step transition probability obtained was used to infer the photoionization cross-section. Thus, the methodology combining two-color, three-photon photoionization and two-color fluorescence signals in a single experiment has been established for the first time to measure the second-step transition probability as well as the photoionization cross-section. - Highlights: • Laser-induced photoionization and fluorescence signals have been simultaneously observed. • The density matrix formalism has been employed to analyze these signals. • Two-color laser-induced fluorescence was used to measure the second-step transition probability. • The second-step transition probability obtained was used to infer the photoionization cross-section. • Transition probability and photoionization cross-section have been measured in a single experiment

  10. 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

  11. Fluorescence/bioluminescence resonance energy transfer techniques to study G-protein-coupled receptor activation and signaling.

    Science.gov (United States)

    Lohse, Martin J; Nuber, Susanne; Hoffmann, Carsten

    2012-04-01

    Fluorescence and bioluminescence resonance energy transfer (FRET and BRET) techniques allow the sensitive monitoring of distances between two labels at the nanometer scale. Depending on the placement of the labels, this permits the analysis of conformational changes within a single protein (for example of a receptor) or the monitoring of protein-protein interactions (for example, between receptors and G-protein subunits). Over the past decade, numerous such techniques have been developed to monitor the activation and signaling of G-protein-coupled receptors (GPCRs) in both the purified, reconstituted state and in intact cells. These techniques span the entire spectrum from ligand binding to the receptors down to intracellular second messengers. They allow the determination and the visualization of signaling processes with high temporal and spatial resolution. With these techniques, it has been demonstrated that GPCR signals may show spatial and temporal patterning. In particular, evidence has been provided for spatial compartmentalization of GPCRs and their signals in intact cells and for distinct physiological consequences of such spatial patterning. We review here the FRET and BRET technologies that have been developed for G-protein-coupled receptors and their signaling proteins (G-proteins, effectors) and the concepts that result from such experiments. PMID:22407612

  12. Fluorescence detection of telomerase activity in cancer cell extracts based on autonomous exonuclease III-assisted isothermal cycling signal amplification.

    Science.gov (United States)

    Ding, Caifeng; Li, Xiaoqian; Wang, Wei; Chen, Yaoyao

    2016-09-15

    Based on the extension reaction of a telomerase substrate (TS) primer in the presence of the telomerase, strand-displacement process to perform more stable longer duplex chain, and stepwise hydrolysis of mononucleotides from the blunt or the recessed 3'-hydroxyl termini of duplex DNA in the presence of Exonuclease III (Exo III), an amplified fluorescence detection of telomerase activity in the cancer cells was described in this manuscript. A fluorescence probe DNA, a quencher DNA, and a TS primer were mixed to construct a three-chain DNA structure and a two-chain DNA structure because the amount of the TS primer was less than the other two DNA. In the presence of the telomerase, the quencher DNA was replaced from the probe DNA and the telomerase activity could be determined with the fluorescence enhancement. The telomerase activity in HeLa extracts equivalent to 6-2000 cells was detected by this method. Moreover, the strategy was further proved by using telomerase extracted from Romas cells. With the multiple rounds of isothermal strand displacement and the hydrolysis process, constituted consecutive of signal amplification for the novel detection paradigm that allowed measuring of telomerase activity in crude cancer cell extracts confirmed the reliability and practicality of the protocol, which reveal this platform holds great promise in the biochemical assay for the telomerase activity in early diagnosis for cancers. PMID:27108253

  13. Improved signal-to-noise ratio for non-perpendicular detection angles in x-ray fluorescence computed tomography (XFCT)

    Science.gov (United States)

    Sjölin, Martin; Danielsson, Mats

    2014-11-01

    The standard imaging setup in x-ray fluorescence computed tomography detects the fluorescence emission at a right angle with respect to the axis of the excitation beam. In this paper we have studied how the detection angle affects the signal-to-noise ratio (S/N), which is a major factor influencing the low-contrast sensitivity of the imaging system. This is done for an imaging setup using a collimated detector and a pencil beam of excitation x-rays. An ideal detection process is simulated for a generalized imaging case with gold/platinum tracers and experimental measurements are performed using a diagnostic x-ray tube. For monochromatic excitation, the results indicate that order-of-magnitude improvements of the S/N can be achieved by optimizing the detection angle. The maximal S/N, when exciting with an energy just above the K-edge, is achieved for large detection angles, i.e. with the detector close to the source. The improvements also transfer to polychromatic excitation sources and the experimental results show up to four-fold improvements of the S/N when changing the detection angle from 90° to 150°. Also, the changes of the S/N behavior when switching the fluorescent tracer is briefly demonstrated. These results suggest that the choice of detection angle should be taken seriously in the design of future XFCT imaging systems.

  14. Fluorescent detection of ATP based on signaling DNA aptamer attached silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yanyan; Wang Yusong; Liu Bin [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117567 (Singapore)], E-mail: cheliub@nus.edu.sg

    2008-10-15

    Novel methods for rapid, sensitive and low-cost biomolecule detection have attracted particular interest because of their wide use in medical diagnostics, food inspection and biomedical research applications. In this work, we report a simple and efficient silica nanoparticle (NP)-based fluorescent assay for ATP detection. It takes advantage of the washing and separation properties of NPs and the structure-switch property of DNA aptamers, resulting in fluorescence change of the supernatant in the presence of targets. A linear response for ATP detection was observed from 0 to 6 mM with a detection limit of {approx}34 {mu}M. This detection strategy could be generalized to other aptamer-based detection systems.

  15. Improvement of the signal-to-noise ratio of laser-induced-fluorescence photon-counting signals of single-atoms magneto-optical trap

    International Nuclear Information System (INIS)

    Employing grating extended-cavity diode lasers as the cooling/trapping and repumping lasers for preparing and manipulating single atoms, we have implemented a large-magnetic-gradient caesium magneto-optical trap (MOT). To detect and evaluate single caesium atoms trapped in MOT, laser-induced-fluorescence (LIF) photons of trapped atoms driven by MOT lasers are collected and counted by an avalanched photodiode worked in photon-counting mode. The dependences of LIF photon-counting signals of single atoms on a cooling laser's intensity, frequency detuning and frequency fluctuation are analysed and investigated. Remarkable improvement of the signal-to-noise ratio of LIF photon-counting signals is achieved by optimizing the cooling laser's intensity and frequency detuning and using the modulation-free polarization spectroscopic technique with feedback to both the slow channel (piezoelectric transducer channel with typical bandwidth of ∼2 kHz in the grating extended cavity) and the fast channel (current modulation channel with typical bandwidth of ∼200 kHz in the current driver).

  16. Quantification of plant chlorophyll content using Google Glass.

    Science.gov (United States)

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

    2015-04-01

    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. PMID:25669673

  17. Endolithic chlorophyll d-containing phototrophs

    DEFF Research Database (Denmark)

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

    2011-01-01

    Cyanobacteria in the genus Acaryochloris are the only known oxyphototrophs that have exchanged chlorophyll a (Chl a) with Chl d as their primary photopigment, facilitating oxygenic photosynthesis with near infrared (NIR) light. Yet their ecology and natural habitats are largely unknown. We used...... 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...... of Chl d-containing cyanobacteria in a range of hitherto unexplored endolithic habitats, where NIR light-driven oxygenic photosynthesis may be significant....

  18. 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...

  19. Automated segmentation and analysis of fluorescent in situ hybridization (FISH) signals in interphase nuclei of pap-smear specimens

    Science.gov (United States)

    Wang, Xingwei; Zheng, Bin; Li, Shibo; Zhang, Roy R.; Li, Yuhua; Mulvihill, John J.; Chen, Wei R.; Liu, Hong

    2009-02-01

    Interphase fluorescence in situ hybridization (FISH) technology is a potential and promising molecular imaging tool, which can be applied to screen and detect cervical cancer. However, manual FISH detection method is a subjective, tedious, and time-consuming process that results in a large inter-reader variability and possible detection error (in particular for heterogeneous cases). Automatic FISH image analysis aims to potentially improve detection efficiency and also produce more accurate and consistent results. In this preliminary study, a new computerized scheme is developed to automatically segment analyzable interaphase cells and detect FISH signals using digital fluorescence microscopic images acquired from Pap-smear specimens. First, due to the large intensity variations of the acquired interphase cells and overlapping cells, an iterative (multiple) threshold method and a feature-based classifier are applied to detect and segment all potentially analyzable interphase nuclei depicted on a single image frame. Second, a region labeling algorithm followed up a knowledge-based classifier is implemented to identify splitting and diffused FISH signals. Finally, each detected analyzable cell is classified as normal or abnormal based on the automatically counted number of FISH signals. To test the performance of this scheme, an image dataset involving 250 Pap-smear FISH image frames was collected and used in this study. The overall accuracy rate for segmenting analyzable interphase nuclei is 86.6% (360/424). The sensitivity and specificity for classifying abnormal and normal cells are 88.5% and 86.6%, respectively. The overall cell classification agreement rate between our scheme and a cytogeneticist is 86.6%. The testing results demonstrate the feasibility of applying this automated scheme in FISH image analysis.

  20. Performance of fluorescence retrieval methods and fluorescence spectrum reconstruction under various sensor spectral configurations

    Science.gov (United States)

    Li, Rong; Zhao, Feng

    2015-10-01

    Solar-induced chlorophyll fluorescence is closely related to photosynthesis and can serve as an indicator of plant status. Several methods have been proposed to retrieve fluorescence signal (Fs) either at specific spectral bands or within the whole fluorescence emission region. In this study, we investigated the precision of the fluorescence signal obtained through these methods under various sensor spectral characteristics. Simulated datasets generated by the SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes) model with known `true' Fs as well as an experimental dataset are exploited to investigate four commonly used Fs retrieval methods, namely the original Fraunhofer Line Discriminator method (FLD), the 3 bands FLD (3FLD), the improved FLD (iFLD), and the Spectral Fitting Methods (SFMs). Fluorescence Spectrum Reconstruction (FSR) method is also investigated using simulated datasets. The sensor characteristics of spectral resolution (SR) and signal-to-noise ratio (SNR) are taken into account. According to the results, finer SR and SNR both lead to better accuracy. Lowest precision is obtained for the FLD method with strong overestimation. Some improvements are made by the 3FLD method, but it still tends to overestimate. Generally, the iFLD method and the SFMs provide better accuracy. As to FSR, the shape and magnitude of reconstructed Fs are generally consistent with the `true' Fs distributions when fine SR is exploited. With coarser SR, however, though R2 of the retrieved Fs may be high, large bias is likely to be obtained as well.

  1. Resolution and signal-to-noise ratio improvement in confocal fluorescence microscopy using array detection and maximum-likelihood processing

    Science.gov (United States)

    Kakade, Rohan; Walker, John G.; Phillips, Andrew J.

    2016-08-01

    Confocal fluorescence microscopy (CFM) is widely used in biological sciences because of its enhanced 3D resolution that allows image sectioning and removal of out-of-focus blur. This is achieved by rejection of the light outside a detection pinhole in a plane confocal with the illuminated object. In this paper, an alternative detection arrangement is examined in which the entire detection/image plane is recorded using an array detector rather than a pinhole detector. Using this recorded data an attempt is then made to recover the object from the whole set of recorded photon array data; in this paper maximum-likelihood estimation has been applied. The recovered object estimates are shown (through computer simulation) to have good resolution, image sectioning and signal-to-noise ratio compared with conventional pinhole CFM images.

  2. 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.

  3. Photoprotective Energy Dissipation in Higher Plants Involves Alteration of the Excited State Energy of the Emitting Chlorophyll(s) in the Light Harvesting Antenna II (LHCII)*

    OpenAIRE

    Johnson, Matthew P.; Ruban, Alexander V.

    2009-01-01

    Non-photochemical quenching (NPQ), a mechanism of energy dissipation in higher plants protects photosystem II (PSII) reaction centers from damage by excess light. NPQ involves a reduction in the chlorophyll excited state lifetime in the PSII harvesting antenna (LHCII) by a quencher. Yet, little is known about the effect of the quencher on chlorophyll excited state energy and dynamics. Application of picosecond time-resolved fluorescence spectroscopy demonstrated that NPQ involves a red-shift ...

  4. Recognition- and Reactivity-Based Fluorescent Probes for Studying Transition Metal Signaling in Living Systems

    OpenAIRE

    Aron, Allegra T.; Ramos-Torres, Karla M.; Cotruvo, Joseph A.; Chang, Christopher J.

    2015-01-01

    Conspectus Metals are essential for life, playing critical roles in all aspects of the central dogma of biology (e.g., the transcription and translation of nucleic acids and synthesis of proteins). Redox-inactive alkali, alkaline earth, and transition metals such as sodium, potassium, calcium, and zinc are widely recognized as dynamic signals, whereas redox-active transition metals such as copper and iron are traditionally thought of as sequestered by protein ligands, including as static enzy...

  5. Aggregation-induced emissive nanoparticles for fluorescence signaling in a low cost paper-based immunoassay.

    Science.gov (United States)

    Engels, Jan F; Roose, Jesse; Zhai, Demi Shuang; Yip, Ka Man; Lee, Mei Suet; Tang, Ben Zhong; Renneberg, Reinhard

    2016-07-01

    Low cost paper based immunoassays are receiving interest due to their fast performance and small amounts of biomolecules needed for developing an immunoassay complex. In this work aggregation-induced emissive (AIE) nanoparticles, obtained from a diastereoisomeric mixture of 1,2-di-(4-hydroxyphenyl)-1,2-diphenylethene (TPEDH) in a one-step top-down method, are characterized through Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and Zeta potential. By measuring the Zeta potential before and after labeling the nanoparticles with antibodies we demonstrate that the colloidal system is stable in a wide pH-range. The AIE-active nanoparticles are deposited on chitosan and glutaraldehyde modified paper pads overcoming the common aggregation-caused quenching (ACQ) effect. Analyte concentrations from 1000ng and below are applied in a model immunocomplex using Goat anti-Rabbit IgG and Rabbit IgG. In the range of 7.81ng-250ng, linear trends with a high R(2) are observed, which leads to a strong increase of the blue fluorescence from the TPEDH nanoparticles. PMID:27037781

  6. Characterization of the latent membrane protein 1 signaling complex of Epstein-Barr virus in the membrane of mammalian cells with bimolecular fluorescence complementation

    Directory of Open Access Journals (Sweden)

    Everly David N

    2011-08-01

    Full Text Available Abstract Background Bimolecular fluorescence complementation (BiFC is a novel technique to examine protein-protein interaction through the assembly of fluorescent proteins. In the present study, BiFC was used to study the assembly of the Epstein-Barr virus latent membrane protein 1 (LMP1 signaling complex within the membrane of mammalian cells. LMP1 signaling requires oligomerization, localization to lipid rafts, and association of the cytoplasmic domain to adaptor proteins, such as the tumor necrosis factor receptor associated factors (TRAFs. Methods LMP1-TRAF and LMP1-LMP1 interactions were assayed by BiFC using fluorescence microscopy and flow cytometry. Function of LMP1 BiFC contructs were confirmed by transformation assays and nuclear factor- κB (NF-κB reporter assays. Results BiFC was observed between LMP1 and TRAF2 or TRAF3 and mutation of the LMP1 signaling domains reduced complementation. Fluorescence was observed in previously described LMP1 signaling locations. Oligomerization of LMP1 with itself induced complementation and BiFC. LMP1-BiFC constructs were fully functional in rodent fibroblast transformation assays and activation of NF-κB reporter activity. The BiFC domain partially suppressed some LMP1 mutant phenotypes. Conclusions Together these data suggest that BiFC is a unique and novel platform to identify and characterize proteins recruited to the LMP1-signaling complex.

  7. EFFECTS OF SIMULATED ACID RAIN STRESS ON GAS EXCHANGE AND CHLOROPHYLL A FLUORESCENCE PARAMETERS IN LEAVES OF LONGAN%模拟酸雨对龙眼叶片气体交换和叶绿素a荧光参数的影响

    Institute of Scientific and Technical Information of China (English)

    邱栋梁; 刘星辉; 郭素枝

    2002-01-01

    Longan (Dimorcarpus longana Lour. cv. Wulongling) seedlings of two different ages grown in pots were selected to study the effects of acid rain stress on gas exchange, and chlorophyll a fluorescence parameters and their recovery. Sulfuric acid and nitric acid were selected for the preparation of artificial acid rain, based on the mole ratio 1:5 of sulfuric acid to nitric acid in the precipitation of southern Fujian. Dilution of reagent grade acid was done with distilled water and determined by Phsj-4 acidity analyzer. A series of solutions of simulated acid rains with pH 5.6, 3.0 and 2.5 were prepared. A sprayer was used to apply the acid solution to young trees. At each application, leaves were thoroughly wetted. Sprays were repeated 12 times in 6 h at 30 min intervals. Gas exchange was detected with an open gas analyzer CID-301PS, and chlorophyll a fluorescence parameters with OS5-FL modulated chlorophyll fluorometer.The results showed that photosynthesis was inhibited by acid rain stress, and light compensation point (LCP) of stressed leaves increased. Gas exchange and chlorophyll a fluorescence parameters of leaves were reduced after 6 h stress with acid rain of pH 3.0, and could be recovered to the level of control 72 h after the treatment ended. Net photosynthetic rate (Pn), stomatal conductance (Cs), transpiration rate (Tr), ratio of variable fluorescence to initial fluorescence (Fv/F0), ratio of variable fluorescence to maximum fluorescence (Fv/Fm), quantum yield of PSⅡelectron transport (ΦPSⅡ), ratio of fluorescence decrease (Rfd), nonphotochemical quenching (qN) and photochemical quenching (qP) were reduced after a 6 h stress with acid rain of pH 2.5, and could not be recovered 72 h after the stress ceased. Intercellular CO2 concentration (Ci) decreased under treatment with acid rain of pH 2.5, rose in the first day and surpassed the level of control 72 h after the acid rain spraying stopped. Dark respiration (Rd) was increased by acid rain, and

  8. Novel type of red-shifted chlorophyll a antenna complex from Chromera velia: II. Biochemistry and spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Bína, David; Gardian, Zdenko; Herbstová, Miroslava; Kotabová, Eva; Koník, P.; Litvín, Radek; Prášil, Ondřej; Tichý, Josef; Vácha, František

    2014-01-01

    Roč. 1837, č. 6 (2014), s. 802-810. ISSN 0005-2728 R&D Projects: GA ČR GBP501/12/G055 Institutional support: RVO:60077344 ; RVO:61388971 Keywords : Chromera velia * red-shifted chlorophyll * Chlorophyll fluorescence Subject RIV: CE - Biochemistry; CE - Biochemistry (MBU-M) Impact factor: 5.353, year: 2014

  9. Effects of Reduced Solar Radiation on Chlorophyll Fluorescence Parameters and Gas Exchange in Winter Wheat of Grain Filling Periods%太阳辐射减弱对冬小麦灌浆期叶绿素荧光及气体交换的影响

    Institute of Scientific and Technical Information of China (English)

    郑有飞; 倪艳利; 麦博儒; 冯妍; 孙健; 李健; 徐静馨

    2011-01-01

    In the recent years, global dimming of solar irradiance is growing due to the increase of aerosols, air pollutants and population density. In order to elucidate the effects of reduced solar irradiance on chlorophyll fluorescence parameters and gas exchange of winter wheat cultivar, we conducted a field experiment in Nanjing city by using the Triticum aestivum L. (cv.Yang mai 13) as the experimental plants. Five reduced solar radiation treatments were set up in the experiments, including 15%(T4), 20%(T3), 40%(T2), 60%(T1 )and 100%(CK)of natural solar radiation, while using Diving-PAM chlorophyll fluorometer and Lcpro+ photosynthesis to measured at different grain filling stages of crop chlorophyll fluorescence and gas exchange of the dynamic changes. The results showed that reducing solar radiation significantly increased chlorophyll and lutein content of winter wheat in the grain filling stage, but the Chla/Chlb and photosynthetic rate( Pn) continued to decrease. Fv/Fm, qP, Y( NO), ( 1 -qP)INPQ and the actual photochemical efficiency(Yield) increased with solar radiation intensity decreased, and show a downward trend, but NPQ, Y (NPQ) and L (PFD) rised. Visible, less solar radiationis cut in winter wheat leaves, when the primary photochemical reaction of PS II electron transfers efficiency met the energy shortage of stress( a decline in photochemical quenching qP). Meanwhile, reducing the electronic delivery of the body (PQ) activity (quantum efficiency Yield was lower), was to increase the heat dissipation leaves, resulting in reduced photosynthetic capacity.%以冬小麦为供试材料,在大用试验条件下研究了模拟太阳辐射减弱对冬小麦旗叶光合色素、叶绿素荧光参数及气体交换的影响.试验中设计了15%、20% 、40% 、60%和100%(CK)自然太阳总辐射5种太阳总辐射处理,同时采用Diving-PAM叶绿素荧光仪和LCpro+光合仪测定了不同灌浆阶段作物叶绿素荧光及气体交换参数的动态

  10. 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

  11. Quantitative Estimation of Fluorescence Parameters for Crop Leaves with Bayesian Inversion

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2015-10-01

    Full Text Available In this study, backward and forward fluorescence radiance within the emission spectrum of 640–850 nm were measured for leaves of soybean, cotton, peanut and wheat using a hyperspectral spectroradiometer coupled with an integration sphere. Fluorescence parameters of crop leaves were retrieved from the leaf hyperspectral measurements by inverting the FluorMODleaf model, a leaf-level fluorescence model able to simulate chlorophyll fluorescence spectra for both sides of leaves. This model is based on the widely used and validated PROSPECT (leaf optical properties model. Firstly, a sensitivity analysis of the FluorMODleaf model was performed to identify and quantify influential parameters to assist the strategy for the inversion. Implementation of the Extended Fourier Amplitude Sensitivity Test (EFAST method showed that the leaf chlorophyll content and the fluorescence lifetimes of photosystem I (PSI and photosystem II (PSII were the most sensitive parameters among all eight inputs of the FluorMODleaf model. Based on results of sensitivity analysis, the FluorMODleaf model was inverted using the leaf fluorescence spectra measured from both sides of crop leaves. In order to achieve stable inversion results, the Bayesian inference theory was applied. The relative absorption cross section of PSI and PSII and the fluorescence lifetimes of PSI and PSII of the FluorMODleaf model were retrieved with the Bayesian inversion approach. Results showed that the coefficient of determination (R2 and root mean square error (RMSE between the fluorescence signal reconstructed from the inverted fluorescence parameters and measured in the experiment were 0.96 and 3.14 × 10−6 W·m−2·sr−1·nm−1, respectively, for backward fluorescence, and 0.92 and 3.84 × 10−6 W·m−2·sr−1·nm−1 for forward fluorescence. Based on results, the inverted values of the fluorescence parameters were analyzed, and the potential of this method was investigated.

  12. The Application of Variable Chlorophyll Fluorescenceto Microphytobenthic Biofilms

    OpenAIRE

    Perkins, Rupert G.; Kromkamp, Jacco C.; Serôdio, Joao; Lavaud, Johann; Jesus, Bruno; Mouget, Jean-Luc; Lefebvre, Sébastien; Forster, R. M.

    2010-01-01

    Community assemblages of diatoms, green algae andcyanobacteria comprise the microphytobenthos (MPB),which inhabit benthic sediment ecosystems (Admiraal1984; Underwood and Kromkamp 1999; Consalvey et al. 2004). Particular attention has been paid to theanalysis of intertidal soft sediment systems, e.g. cohesivemudflat and sandy substrata typical of estuarine habitats.Variable chlorophyll fluorescence has been applied tothese systems since the 1990s, in an attempt to investigatethe primary produ...

  13. Effect of supplementary VB radiation on chlorophyll synthesis and accumulation of photosystems during chloroplast development in Spirodela oligorrhiza

    International Nuclear Information System (INIS)

    Although the effects of ultraviolet B (UVB, 290-320 nm) radiation have been studied in plants extensively, little is known about the potential impacts on maturation of chloroplasts. To address this problem, the effects of supplementary UVB on chloroplast development were examined in the aquatic higher plant Spirodela oligorrhiza. Dark-grown Spirodela-containing proplastids were exposed to photosynthetically active radiation (PAR) and ultraviolet A (UVA, 320-400 nm), plus supplementary UVB equivalent to 1% of PAR on a photon basis. The biosynthesis and assembly of chlorophyll (Chl) into reaction centers was followed for 4 days in situ by low temperature (77 K) Chl fluorescence. Impacts on chloroplast development were detected after only 1 h incubation in light with supplementary UVB. Fluorescence emission signals from Chl associated with the photosystem (PS) II antenna, PSII reaction centers and PSI reaction centers were detected at the same time with or without UVB, but the magnitude of PS fluorescence was diminished up to 60% in plants incubated in UVB. The Chl content was also lower in UVB-treated plants, but to a lesser degree than anticipated by low temperature fluorescence, suggesting lack of organization and/or association of Chl with PS. Electron transport, measured with room temperature fluorescence induction, was not consistently different in plants exposed to UVB. These results suggest that with UVB, fewer and/or smaller PS form during chloroplast development, but there is not a large inhibition of Chl synthesis or PSII activity. (Author)

  14. Probing of chlorophyll a with pulsed tunable laser

    International Nuclear Information System (INIS)

    Probing with a tunable pulsed dye laser of a solution of chlorophyll a in pyridine is reported. Transmission studies at fixed wavelengths as function of laser intensity reveal that various levels within the singlet and triplet system become populated and the life-time of these excited states is determined. Fluorescence in the blue part of the electromagnetic spectrum is recorded and the spectrum is induced as a result of the consecutive absorption of two red photons. Using time resolved spectroscopical detection methods, the fluorescence spectra of dimers, free from interference of that due to the monomer, are recorded. (orig.)

  15. Design of a Real-time Signal Processing System for LIF Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Xiande; Zheng Wengang; Dong Daming; Shen Changjun; Zhang Xin; Zhou Jianjun; Yan Hua; Wu Wenbiao, E-mail: zhengwg@nercita.org.cn [National Engineering Research Center for Information Technology in Agriculture, 100097 (China)

    2011-02-01

    Laser Induced Fluorescence (LIF) sensor is one of the most sensitive approaches available for a variety of analytical applications, such as determination of nitrogen content of plant leaves, detection of chlorophyll content in water, etal. As a core instrumental requirements of real time LIF sensor, signal processing system is used to store effective processing and identification algorithms in a short time. By analyzing the working principle of LIF sensor in detail, a novel platform of signal processing system used in LIF sensor is proposed in this paper. The design solutions and hardware architecture of the system are described in this paper, include Digital Signal Processor (DSP), data transmission block, and memory block. Several steps of signal processing methods are proposed, according to the characteristic of LIF sensor. At last, an application of using the signal processing system designed in this paper for measuring chlorophyll content in plant leaves is shown.

  16. Effects of magnesium on chlorophyll fluorescence and active oxygen scavenging system of fruiting-node leaves of muskmelon%镁对厚皮甜瓜坐果节位叶片叶绿素荧光特性和活性氧清除系统的影响

    Institute of Scientific and Technical Information of China (English)

    朱立保; 刘海河; 张彦萍; 张利云; 王正

    2015-01-01

    [Objectives] Muskmelon leaves are often premature senescent at the fruit ripening stage, especially the leaves located on the fruiting-node, seriously decreasing the functions of photosynthetic system and fruit growth. The effects of magnesium on improving function of chlorophyll fluorescence and active oxygen scavenging system were studied. [Methods] Muskmelon cultivar‘Yingchun( F1 ) ’ was used as test material and sprayed with MgSO4 solution of 0 , 2 , 4 and 6 mmol/L on the day when female flowers on fruiting-nodes were opening and being hand-pollinated. The sprays were made once a week and 3 sprays in all. Every other week, the physiological indexes of leaves on fruiting-nodes were determined after the first spray. The chlorophyll fluorescence and photosynthesischaracteristics were measured using imaging fluorescence spectrometer MINI-IMAGING-PAM and portable photosynthesis system Li-6400, the leaf Mg content by ICP-OES method, and the enzyme activities and the contents of malondialdehyde( MDA) , soluble sugar and soluble protein in the fruits were measured referring to the LI He-sheng’s experiment method, the soluble solids with a handheld sugar meter, and the Vc content by 2, 6-dichloro phenol indophenol titration method. [Results] From analyzing physiological indexes of leaves on fruiting-nodes and fruits, the following results can be obtained: the spray of 2 mmol/L and 4 mmol/L Mg2+ could significantly increase the Mg levels in fruiting-node leaves, and delay the degradation rate of chlorophyll during the process of leaf senescence at the same time. Some chlorophyll fluorescence and photosynthesis characteristic parameters, including the maximal photochemical efficiency(Fv/Fm), quantum yield of PSII electron transport (ФPSⅡ) , apparent electron transport rate( ETR) and net photosynthetic rate are promoted at various degrees under the 2 mmol/L and 4 mmol/L Mg2+treatments, while the minimal fluorescence( Fo) is decreased dramatically. The antioxidant

  17. Construction of fluorescence resonance energy transfer vectors and their application in study of structure and function of signal transducers and activators of transcription 1

    Institute of Scientific and Technical Information of China (English)

    Fujun Han; Yongfeng Luo; Nanhai Ge; Jun Xu

    2008-01-01

    Protein-protein interactions have been studied extensively by green fluorescent protein-based fluorescence resonance energy transfer (FRET). The fluorescent proteins (FP) can be fused either to the N- or C-terminus of a host protein, but it is difficult to predict which order will perturb the host protein the least and provide the largest FRET. Therefore, a researcher needs to fuse host proteins with FP at both the N- and C-termini and test every possible combination (N-N,N-C, or C-C) to promote the energy transfer efficiency.Consequently, researchers required to do many subelonings.Herein, we designed FRET vectors to make them more efficient. The expression vectors ofpCTP.YFP and pYFP-CFP were constructed with both cyan fluorescent protein (CFP)-yellow fluorescent protein (YFP) and YFP-CFP coding sequences flanked by two restriction enzyme sites, and with multiple cloning regions in the middle of both coding sequences. To select an optimal combination for FRET detection, we created plasmids encoding various fusion proteins of FP and signal transducers and activators of transcription 1 (STAT1). We found that the nuclear:cytoplasmic fluorescence intensity ratios of STAT1 -FP were significantly higher than those of FP-STAT1 at steady state,and fluorescence redistribution was only observed for STAT1-FP upon interferon gamma (IFNΥ) stimulation. In addition, positive FRET signals were only detected in the C-C interactions of STAT 1 homodimer. Taken together, these data indicate that fusing STATI at the N.terminus with Fpimpairs the interactions ofunphospborylated STAT1 homodimers and possibly diminishes its binding with DNA. In contrast, STATIFP was functional with respect to its activation. Moreover, the FRET vectors are able to facilitate FRET studies.

  18. Near-infrared fluorescence imaging of cancer mediated by tumor hypoxia and HIF1α/OATPs signaling axis

    Science.gov (United States)

    Wu, Jason Boyang; Shao, Chen; Li, Xiangyan; Shi, Changhong; Li, Qinlong; Hu, Peizhen; Chen, Yi-Ting; Dou, Xiaoliang; Sahu, Divya; Li, Wei; Harada, Hiroshi; Zhang, Yi; Wang, Ruoxiang; Zhau, Haiyen E.; Chung, Leland W.K.

    2014-01-01

    Near-infrared fluorescence (NIRF) imaging agents are promising tools for noninvasive cancer imaging. Here, we explored the mechanistic properties of a specific group of NIR heptamethine carbocyanines including MHI-148 dye we identified and synthesized, and demonstrated these dyes to achieve cancer-specific imaging and targeting via a hypoxia-mediated mechanism. We found that cancer cells and tumor xenografts exhibited hypoxia-dependent MHI-148 dye uptake in vitro and in vivo, which was directly mediated by hypoxia-inducible factor 1α (HIF1α). Microarray analysis and dye uptake assay further revealed a group of hypoxia-inducible organic anion-transporting polypeptides (OATPs) responsible for dye uptake, and the correlation between OATPs and HIF1α was manifested in progressive clinical cancer specimens. Finally, we demonstrated increased uptake of MHI-148 dye in situ in perfused clinical tumor samples with activated HIF1α/OATPs signaling. Our results establish these NIRF dyes as potential tumor hypoxia-dependent cancer-targeting agents and provide a mechanistic rationale for continued development of NIRF imaging agents for improved cancer detection, prognosis and therapy. PMID:24957295

  19. The signal sequence of exported protein-1 directs the green fluorescent protein to the parasitophorous vacuole of transfected malaria parasites.

    Science.gov (United States)

    Adisa, Akinola; Rug, Melanie; Klonis, Nectarios; Foley, Michael; Cowman, Alan F; Tilley, Leann

    2003-02-21

    The malaria parasite, Plasmodium falciparum, spends part of its life cycle inside the erythrocytes of its human host. In the mature stages of intraerythrocytic growth, the parasite undertakes extensive remodeling of its adopted cellular home by exporting proteins beyond the confines of its own plasma membrane. To examine the signals involved in export of parasite proteins, we have prepared transfected parasites expressing a chimeric protein comprising the N-terminal region of the Plasmodium falciparum exported protein-1 appended to green fluorescent protein. The majority of the population of the chimeric protein appears to be correctly processed and trafficked to the parasitophorous vacuole, indicating that this is the default destination for protein secretion. Some of the protein is redirected to the parasite food vacuole and further degraded. Photobleaching studies reveal that the parasitophorous vacuole contains subcompartments that are only partially interconnected. Dual labeling with the lipid probe, BODIPY-TR-ceramide, reveals the presence of membrane-bound extensions that can bleb from the parasitophorous vacuole to produce double membrane-bound compartments. We also observed regions and extensions of the parasitophorous vacuole, where there is segregation of the lumenal chimera from the lipid components. These regions may represent sites for the sorting of proteins destined for the trafficking to sites beyond the parasitophorous vacuole membrane. PMID:12456681

  20. Investigating the Control of Chlorophyll Degradation by Genomic Correlation Mining.

    Science.gov (United States)

    Ghandchi, Frederick P; Caetano-Anolles, Gustavo; Clough, Steven J; Ort, Donald R

    2016-01-01

    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 network includes the

  1. Study on the Correlation Between Chlorophyll Maximum and Remote Sensing Data

    Institute of Scientific and Technical Information of China (English)

    XIU Peng; LIU Yuguang

    2006-01-01

    Based on the in situ optical measurements in the Bohai Sea of China, which belongs to a typical case-2 water area, we studied the characteristics of DCM (deep chlorophyll maximum) such as its spatial distribution, vertical profile,etc.We found that when the depth of the chlorophyll maximum is comparatively small, even in turbid coastal water regions,there is always a good correlation between the concentrations of chlorophyll maximum and the satellite-received signals in blue-green spectral bands; the correlation is even better than that between the surface chlorophyll concentrations and the satellite-received signals.The strong correlation existing even in turbid coastal water regions indicates that an ocean color model to retrieve the concentration of DCM can be constructed for coastal waters if a comprehensive knowledge of the vertical distribution of chlorophyll concentration in the Bohai Sea of China is available.

  2. Optical Reflectance and Fluorescence for Detecting Nitrogen Needs in Zea mays L.

    Science.gov (United States)

    McMurtrey, J. E.; Middleton, E. M.; Corp. L. A.; Campbell, P. K. Entcheva; Butcher, L. M.; Daughtry, C. S. T.

    2003-01-01

    Nitrogen (N) status in field grown corn (Zea mays L.) was assessed using spectral techniques. Passive reflectance remote sensing and, both passive and active fluorescence sensing methods were investigated. Reflectance and fluorescence methods are reported to detect changes in the primary plant pigments (chlorophylls a and b; carotenoids) in higher plant species. As a general rule, foliar chlorophyll a (Chl a) and chlorophyll b (Chl b) usually exist in approx.3:l ratio. In plants under stress, Chl b content is affected before Chl a reductions occur. For reflectance, a version of the chlorophyll absorption in reflectance index (CARI) method was tested with narrow bands from the Airborne Imaging Spectroradiometer for Applications (ASIA). CARI minimizes the effects of soil background on the signal from green canopies. A modified CARI (MCARI) was used to track total Chl a levels in the red dip of the spectrum from the corn canopy. A second MCARI was used to track the auxiliary plant pigments (Chl b and the carotenoids) in the yellow/orange/red edge part of the reflectance spectrum. The difference between these two MCARI indices detected variations in N levels across the field plot canopies using ASIA data. At the leaf level, ratios of fluorescence emissions in the blue, green, red and far-red wavelengths sensed responses that were associated with the plant pigments, and were indicative of energy transfer in the photosynthetic process. N stressed corn stands could be distinguish from those with optimally applied N with fluorescence emission spectra obtained from individual corn leaves. Both reflectance and fluorescence methods are sensitive in detecting corn N needs and may be especially powerful in monitoring crop conditions if both types of information can be combined.

  3. Chlorophyll modulation of mixed layer thermodynamics in a mixed-layer isopycnal General Circulation Model - An example from Arabian Sea and equatorial Pacific

    Indian Academy of Sciences (India)

    S Nakamoto; S Prasanna Kumar; J M Oberhuber; H Saito; K Muneyama; R Frouin

    2002-09-01

    Western tropical Indian Ocean, Arabian Sea, and the equatorial Pacific are known as regions of intense bio-chemical-physical interactions: the Arabian Sea has the largest phytoplankton bloom with seasonal signal, while the equatorial Pacific bloom is perennial with quasi-permanent upwelling. Here, we studied three dimensional ocean thermodynamics comparing recent ocean observation with ocean general circulation model (OPYC) experiment combined with remotely sensed chlorophyll pigment concentrations from the Coastal Zone Color Scanner (CZCS). Using solar radiation parameterization representing observations that a higher abundance of chlorophyll increases absorption of solar irradiance and heating rate in the upper ocean, we showed that the mixed layer thickness decreases more than they would be under clear water conditions. These changes in the model mixed layer were consistent with Joint Global Ocean Flux Study (JGOFS) observations during the 1994-1995 Arabian Sea experiment and epi-fluorescence microscopy (EFM) on samples collected during Equatorial Pacific Ocean Climate Study (EPOCS) in November, 1988. 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 increases. In the equatorial Pacific, modest concentrations of chlorophyll less than 0.3mg/m3 is enough to introduce a meridional differential heating, which results in reducing the equatorial mixed layer thickness to more than 20 m. The anomalous meridional tilting of the mixed layer bottom enhances off equatorial westward geostrophic currents. Consequently, the equatorial undercurrent transports more water from west to east. We proposed that these numerical model experiments with use of satellite and in situ ocean observations are consistent under three

  4. 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.

  5. Chlorophylls, Symmetry, Chirality, and Photosynthesis.

    OpenAIRE

    Mathias O. Senge; Aoife A. Ryan; Kristie A. Letchford; Stuart A. MacGowan; Tamara Mielke

    2014-01-01

    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 ...

  6. Double-staining chromogenic in situ hybridization as a useful alternative to split-signal fluorescence in situ hybridization in lymphoma diagnostics

    DEFF Research Database (Denmark)

    van Rijk, A.; Svenstroup-Poulsen, T.; Jones, M.;

    2010-01-01

    Background Malignant lymphomas are classified based on morphology, immunophenotype, genetics and clinical features. The pathological diagnosis is generally considered difficult and prone to mistakes. Since non-random chromosomal translocations are specifically involved in specific entities, their...... detection is an important adjunct for increasing the reliability of the diagnosis. Recently, split-signal fluorescence hi situ hybridization has become available as a robust method to detect chromosomal breaks in paraffin-embedded formalin-fixed tissues. A bright field approach would bring this technology...... within the reach of every pathology laboratory. Design and Methods Our study was initiated to determine the consistency between chromogenic in situ hybridization and fluorescence in situ hybridization, both using split-signal probes developed for the detection of chromosomal breaks. Five hundred and...

  7. A Graphene Oxide-Based Sensing Platform for the Determination of Methicillin-Resistant Staphylococcus aureus Based on Strand-Displacement Polymerization Recycling and Synchronous Fluorescent Signal Amplification.

    Science.gov (United States)

    Ning, Yi; Gao, Qiang; Zhang, Xiaoqing; Wei, Ke; Chen, Lingli

    2016-09-01

    To develop new technology for detecting methicillin-resistant Staphylococcus aureus (MRSA), a novel fluorescent biosensor based on Klenow fragment (KF)-assisted target recycling amplification and synchronous fluorescence analysis was created. Carboxy-fluorescein (FAM)-labeled single-stranded DNA (ssDNA) containing a capture probe and a signal probe was adsorbed onto the surface of graphene oxide (GO) via π-stacking interactions, resulting in the fluorescence quenching of the dye. When target and primer were introduced, the fluorescence was restored due to P0 being completely released from the surface of the GO. Meanwhile, by using the KF and exploiting the synergistic effect of FAM and the double-stranded DNA (dsDNA)-SYBR Green I duplex structure, the fluorescence in this detection system was considerably amplified and the sensitivity was improved. The proposed strategy for mecA gene analysis showed a good linear range from 1 to 40 nmol/L, with a lower limit of detection of 0.5 nmol/L. In addition, a bacterial sample harboring the mecA gene was also detected, and its lower detection limit was up to 300 colony-forming units (CFU)/mL. Accordingly, this biosensor exhibits high sensitivity and selectivity and has great potential for early clinical diagnosis and treatment. PMID:27286718

  8. A unique "turn-on" fluorescence signalling strategy for highly specific detection of ascorbic acid using carbon dots as sensing probe.

    Science.gov (United States)

    Fong, Jessica Fung Yee; Chin, Suk Fun; Ng, Sing Muk

    2016-11-15

    Carbon dots (CDs) that showed strong blue fluorescence were successfully synthesised from sodium alginate via furnace pyrolysis. The single step pyrolytic synthesis was simple to perform while yielded CDs with high photostability, good water solubility and minimum by-products. In order to design the probe with "turn-on" sensing capability, the CDs were screened against a series of metal cations to first "turn-off" the fluorescence. It was found that ferric ions (Fe(3+)) were most responsive and effective in quenching the fluorescence of CDs. Based on this observation, the conditioning of the probe was performed to ensure the fluorescence was completely quenched, while not overloading the system with Fe(3+). At the optimised condition, the CDs-Fe(3+) mixture served as a highly specific detection probe for ascorbic acid (AA). The analytical potential of the probe was evaluated and showed a good linear range of response for AA concentration of 24-40μg/mL. The selectivity study against other possible co-existing species was carried out and proved that our unique "turn-on" fluorescence signalling strategy was highly effective and selective towards AA as the target analyte. The probe was demonstrated for quantification of AA in real samples, which was the commercially available vitamin C supplement. The result showed good accuracy with minimum deviation from standard method adopted for validation purpose. PMID:27290666

  9. Spectral luminescence and photochemical properties of chlorophyll a in solution containing carbon tetrachloride

    International Nuclear Information System (INIS)

    Studies were conducted on photophysical and photochemical processes in chlorophyll a in carbon tetrachloride and ether by means of flash photolysis, electron spin resonance, and fluorescence spectroscopy. Lifetimes and quenching of triplet states were analyzed and absorption spectra and fluorescence decay times are given. The kinetics of triplet-triplet absorption and hyperfine structure were determined. An absolute quantum yield of the photochemical reaction was measured within the range of linear dependence of the optical density on the time of chlorophyll a irradiation by a krypton laser and the excitation wavelength of 647.1 nm

  10. Detection of microRNAs in frozen tissue sections by fluorescence in situ hybridization using locked nucleic acid probes and tyramide signal amplification

    DEFF Research Database (Denmark)

    Silahtaroglu, Asli; Nolting, Dorrit; Andersen, Lars Dyrskjøt; Berezikov, Eugene; Møller, Morten; Tommerup, Niels; Kauppinen, Markus Sakari

    2007-01-01

    RNAs in frozen tissue sections using fluorescence in situ hybridization (FISH). The method combines the unique miRNA recognition properties of locked nucleic acid (LNA)-modified oligonucleotide probes with FISH using the tyramide signal amplification (TSA) technology. Although both approaches have...... protocol can be completed within approximately 6 h and allows miRNA detection in a wide variety of animal tissue cryosections as well as in human tumor biopsies at high cellular resolution....

  11. Parallel and miniaturised Analysis of Protein-Protein Interactions in T-Cell Signal Transduction by Fluorescence Cross-Correlation Spectroscopy and Peptide Microarrays

    OpenAIRE

    Stoevesandt, Oda

    2006-01-01

    The aim of this thesis was to develop methods for the parallel analysis of complexes of endogenous proteins in T-cell signal transduction. We opted for detection in cell lysates, as the labelling of proteins in lysates is more versatile and more amenable to parallelisation compared to the labelling of proteins in life cells. Two approaches were developed, based on peptide microarrays and on fluorescence correlation and cross correlation spectroscopy (FCS / FCCS). It is shown that peptide m...

  12. Viral Preprotoxin Signal Sequence Allows Efficient Secretion of Green Fluorescent Protein by Candida glabrata, Pichia pastoris, Saccharomyces cerevisiae, and Schizosaccharomyces pombe

    OpenAIRE

    Eiden-Plach, Antje; Zagorc, Tatjana; Heintel, Tanja; Carius, Yvonne; Breinig, Frank; Manfred J Schmitt

    2004-01-01

    Besides its importance as model organism in eukaryotic cell biology, yeast species have also developed into an attractive host for the expression, processing, and secretion of recombinant proteins. Here we investigated foreign protein secretion in four distantly related yeasts (Candida glabrata, Pichia pastoris, Saccharomyces cerevisiae, and Schizosaccharomyces pombe) by using green fluorescent protein (GFP) as a reporter and a viral secretion signal sequence derived from the K28 preprotoxin ...

  13. Double-staining chromogenic in situ hybridization as a useful alternative to split-signal fluorescence in situ hybridization in lymphoma diagnostics

    OpenAIRE

    Rijk, A.; Svenstroup-Poulsen, T.; Jones, M.(Purdue University, West Lafayette, U.S.A.); Cabecadas, J.; Cigudosa, J. C.; Leoncini, L.; Mottok, A; Bergman, C.C.; Pouliou, E.; Dutoit, S H; van Krieken, J H J M

    2009-01-01

    BACKGROUND: Malignant lymphomas are classified based on morphology, immunophenotype, genetics and clinical features. The pathological diagnosis is generally considered difficult and prone to mistakes. Since non-random chromosomal translocations are specifically involved in specific entities, their detection is an important adjunct for increasing the reliability of the diagnosis. Recently, split-signal fluorescence in situ hybridization has become available as a robust method to detect chromos...

  14. Direct patterning of probe proteins on an antifouling PLL-g-dextran coating for reducing the background signal of fluorescent immunoassays

    OpenAIRE

    Egea, Amandine M. C.; Trévisiol, Emmanuelle

    2013-01-01

    The limit of detection of advanced immunoassays, biochips and micro/nano biodetection devices is impacted by the non-specific adsorption of target molecules at the sample surface. In this paper, we present a simple and versatile low cost method for generating active surfaces composed of antibodies arrays surrounded by an efficient anti-fouling layer, capable to decrease drastically the fluorescence background signal obtained after interaction with a solution to be analyzed. The technological ...

  15. 铜胁迫对苋菜叶片叶绿素a荧光诱导动力学的影响%Effects of Copper Stress on the Chlorophyll a Fluorescence Induction Kinetics of Amaranthus mangostanus L.

    Institute of Scientific and Technical Information of China (English)

    林碧英; 谢秋梅; 林义章; 朱海生; 李永裕

    2011-01-01

    The effect of Cu-added nutrient fluid on the root of A rnaranthus mangostanus L. was investigated in this experiment. Also, the function changes of the photosystem Ⅱ (PS Ⅱ ) reaction center in A maranthus mangostanus L.,and the influences of copper in donor and acceptor sides of this system were investigated by the method of fluorescence induction kinetics. The results showed that copper stress inactivated the PS Ⅱ reaction center in the leaves of Amaranthus mangostanus L., decreased the maximal photochemical efficiency of PSⅡ (FV/FM), and damaged the acceptor side of PS Ⅱ seriously and inhibited the transfer of linear electrons, and also did harm to the oxygen evolving complexes (OEC) of the donor side of PS Ⅱ. It could be concluded that the damage of copper stress in Amaranthus mangostanus L. was begun from the donor and acceptor sides of PsⅡin leaves.%以苋菜(Amaranthus mangostanus L.)为材料,采用营养液中添加铜的培养方法,观测了根部生长变化:运用叶绿素荧光分析技术研究了铜胁迫下苋菜光系统Ⅱ(PSⅡ)反应中心结构和功能的变化以及PSⅡ反应中心供体侧和受体侧氧化还原状态的影响.结果表明:铜胁迫使苋菜根部生长受到抑制,叶片PSⅡ反应中心失活:最大光化学效率(FV/FM)下降;叶片PSⅡ受体侧产生严重的伤害,线性电子传递受阻;PSⅡ供体侧的放氧复合体(0EC)受损;铜胁迫对苋菜叶片PSⅡ的伤害从PSⅡ供体侧和受体侧开始.

  16. Differential effects of glyphosate and aminomethylphosphonic acid (AMPA) on photosynthesis and chlorophyll metabolism in willow plants.

    Science.gov (United States)

    Gomes, Marcelo Pedrosa; Le Manac'h, Sarah Gingras; Maccario, Sophie; Labrecque, Michel; Lucotte, Marc; Juneau, Philippe

    2016-06-01

    We used a willow species (Salix miyabeana cultivar SX64) to examine the differential secondary-effects of glyphosate and aminomethylphosphonic acid (AMPA), the principal glyphosate by-product, on chlorophyll metabolism and photosynthesis. Willow plants were treated with different concentrations of glyphosate (equivalent to 0, 1.4, 2.1 and 2.8kgha(-1)) and AMPA (equivalent to 0, 0.28, 1.4 and 2.8kgha(-1)) and evaluations of pigment contents, chlorophyll fluorescence, and oxidative stress markers (hydrogen peroxide content and antioxidant enzyme activities) in leaves were performed after 12h of exposure. We observed that AMPA and glyphosate trigger different mechanisms leading to decreases in chlorophyll content and photosynthesis rates in willow plants. Both chemicals induced ROS accumulation in willow leaves although only glyphosate-induced oxidative damage through lipid peroxidation. By disturbing chlorophyll biosynthesis, AMPA induced decreases in chlorophyll contents, with consequent effects on photosynthesis. With glyphosate, ROS increases were higher than the ROS-sensitive threshold, provoking chlorophyll degradation (as seen by pheophytin accumulation) and invariable decreases in photosynthesis. Peroxide accumulation in both AMPA and glyphosate-treated plants was due to the inhibition of antioxidant enzyme activities. The different effects of glyphosate on chlorophyll contents and photosynthesis as described in the literature may be due to various glyphosate:AMPA ratios in those plants. PMID:27155486

  17. Cyanobacterial chlorophyll as a sensitizer for colloidal TiO 2

    Science.gov (United States)

    Kathiravan, A.; Chandramohan, M.; Renganathan, R.; Sekar, S.

    2009-01-01

    Chlorophyll has been extracted from cyanobacteria. The adsorption of chlorophyll on the surface of colloidal TiO 2 through electrostatic interaction was observed. The apparent association constant ( Kapp) of chlorophyll-TiO 2 obtained from absorption spectra is 3.78 × 10 4 M -1. The Kapp value of chlorophyll-TiO 2 as determined from fluorescence spectra is 1.81 × 10 4 M -1, which matches well with that determined from the absorption spectra changes. These data indicate that there is an interaction between chlorophyll and colloidal TiO 2 nanoparticle surface. The dynamics of photoinduced electron transfer from chlorophyll to the conduction band of colloidal TiO 2 nanoparticle has been observed and the mechanism of electron transfer has been confirmed by the calculation of free energy change (Δ Get) by applying Rehm-Weller equation as well as energy level diagram. Lifetime measurements gave the rate constant ( ket) for electron injection from the excited state chlorophyll into the conduction band of TiO 2 is 4.2 × 10 8 s -1.

  18. Reconstitution of Photosystem Ⅱ Reaction Center with Cu-Chlorophyll a

    Institute of Scientific and Technical Information of China (English)

    Shuang Liu; Feng-Qin Dong; Chun-Hong Yang; Chong-Qin Tang; Ting-Yun Kuang

    2006-01-01

    An isolated photosystem (PS) Ⅱ reaction center (RC) with altered pigment content was obtained by chemical exchange of native chlorophyll a (Chl) with externally added Cu-Chl a (Cu-Chl). Pigment composition and spectroscopic properties of the RC exchanged with Cu-Chl were compared with native RC and RC treated with Chl in the same way. High-performance liquid chromatography analysis showed approximately 0.5 Cu-Chl per two pheophytin in the Cu-Chl-reconstituted RC preparation. Insertion of Cu-Chl resulted in a decrease in absorption at 670 nm and an increase at 660 nm, suggesting that the peripheral Chl may have been displaced. Fluorescence emission spectra of the Cu-Chl-reconstituted RC displayed a marked decrease in fluorescence yield and a blue shift of the band maximum, accompanied by the appearance of a broad peak at a shorter wavelength, indicating that energy transfer in the modified RC was disturbed by Cu-Chl, a quencher of the excited state. However, there were few differences in the circular dichroism (CD) spectra,suggesting that the arrangement of pigments and proteins responsible for the CD signal was not significantly affected. In addition, no obvious change in peptide components was found after the exchange procedure.

  19. Field Detection of Chlorophyll-a Concentration in the Sea Surface Layer by an Airborne Oceanographic Lidar

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An airborne oceanographic lidar, with a frequency-tripled Q-switched Nd: YAG laser of 355 nm, has been designed to measure chlorophyll-a (Chl-a) concentration in the sea surface layer by the Ocean Remote Sensing Institute, OUC. The field experiment was carried out in the bay which is located south of the Liaodong Peninsula on the 10th of September 2005. After the flight, the raw data were processed and analyzed by the fluorescence-to-Raman ratio method with seawater attenuation coefficients calculated from signal profiles. The results of Chl-a concentration measurements by lidar are shown. The measurements in clear sea water were also compared with those of Chl-a concentration by a Moderate Resolution Imaging Spectroradiometer (MODIS).

  20. Characterization of a Synechococcus sp. strain PCC 7002 spontaneous mutant strain defective in accumulation of photosystem II core chlorophyll-protein complexes.

    OpenAIRE

    Webb, R.; Punnett, T

    1989-01-01

    Two photosystem II-associated chlorophyll-protein complexes of Synechococcus sp. strain PCC 7002 were identified. Their polypeptide compositions were similar to those of chlorophyll-containing antenna complexes of other cyanobacteria. Strain GT8B did not possess the complex responsible for 695-nm fluorescence and was unable to grow photoautotrophically; hence, this complex is necessary for photosystem II function in vivo.

  1. Heat-induced disassembly and degradation of chlorophyll-containing protein complexes in vivo. A study with linearly heated barley leaves

    Czech Academy of Sciences Publication Activity Database

    Lípová, L.; Krchňák, P.; Komenda, Josef; Ilík, P.

    2010-01-01

    Roč. 1797, č. 1 (2010), s. 63-70. ISSN 0005-2728 Institutional research plan: CEZ:AV0Z50200510 Keywords : Chlorophyll-containing protein complex * Chlorophyll fluorescence temperature curve * Disassembly Subject RIV: EE - Microbiology, Virology Impact factor: 5.132, year: 2010

  2. Extraction and Analysis of Solar-Induced Chlorophyll Fluorescence of Wheat with Ground-Based Hyperspectral Imaging System%基于近地面高光谱影像的冬小麦日光诱导叶绿素荧光提取与分析

    Institute of Scientific and Technical Information of China (English)

    王冉; 刘志刚; 冯海宽; 杨沛琦; 王庆山; 倪卓娅

    2013-01-01

    结合FluorMOD模型模拟数据与利用光谱分辨率3.3nm、光谱采样间隔为0.71~0.74 nm近地面成像高光谱系统获取的抽穗期小麦高光谱影像比较3种基于夫琅和费线暗线的提取方法(FLD,3FLD和iFLD)的精确性和稳定性.结果表明当光谱分辨率为3.3nm时,在760 m附近的O2-A波段可以有效提取日光诱导叶绿素荧光,而在687 nm附近的O2-B波段不适合.当存在噪声时,FLD和3FLD的稳定性高于iFLD,FLD倾向于高估荧光值.%Dataset simulated with FluorMOD and images of wheat in heading stage taken by a ground-based hyperspectral imaging system with 3.3 nm spectral resolution and 0.71~0.74 nm spectral sampling interval were used test the feasibility and accuracy of three FLD methods (named FLD,3FLD and iFLD).The results show that when spectral resolution is 3.3 nm,solarinduced chlorophyll fluorescence could be extracted effectively in O2-A band (around 760 nm) instead of O2-B band (around 687nm).As to the extraction results of data with noises,both FLD and 3FLD are stabler than iFLD method.The results of FLD tend to be higher than true value.

  3. 铝胁迫下外源有机酸对油菜根系形态及叶绿素荧光特性的影响%Effects of exogenous organic acids on root morphology and chlorophyll fluorescence characteristics of oilseed rape under aluminum stress

    Institute of Scientific and Technical Information of China (English)

    王志颖; 刘鹏; 李锦山; 吴惠芳; 刘莹; 芦伯鑫

    2011-01-01

    Aluminum toxicity in acidic soil has become a major limiting factor in China' s rapeseed oil production. To investigate the effects of exogenous organic acids (citric acid or malic acid) on root morphology and chlorophyll fluorescence characteristics of different Al-tolerant varieties of oilseed rape (Huayou 2790 and Zhongshuang No. 7) , relative root length and total root length as well as chlorophyll fluorescence parameters [ the chlorophyll content, Fm(maximal fluorescence) , Fv/Fo(PS II potential activity) ,φPS II (photochemical quantum yield) ] of oilseed rape with interactive treatments of aluminum (0μmol/L, 50μmol/L,100μmol/L,200μmol/L) and two organic acids (citric acid or malic acid, 20μmol/L) were determined under hydroponics condition. Results showed that, in single aluminum treatment, ail the parameters mentioned above reduced as the Al concentration increased, the sensitive cultivar Huayou 2790 dropping morethan tolerant cultivar Zhongshuang No. 7. After adding exogenous organic acids, the above parameters were unproved. In 200μmol/L Al and organic acid interactive treatment, the relative root length was increased by 14. 9% for Al-tolerant cultivar compared with the same concentration of single Al. The increment of chlorophyllfluorescence parameters in Al-tolerant cultivar were larger than those in Al-sensitive one, and the alleviating effects of citric acid was slightly better than malic acid. It indicated that aluminum stress could inhibit the root growth and photosynthesis of oilseed rape, and adding exogenous organic acids could alleviate the toxicity of aluminum to a certain extent.%为探明铝胁迫下外源有机酸(柠檬酸和苹果酸)对不同耐性油菜品种(华油2790和中双7号)根系形态和叶绿素荧光特性的影响,该研究采用水培法,用分光光度计、根系扫描仪等测定0 μmol/L、50 μmol/L、100μmol/L、200 μmol/L铝和20 μmol/L柠檬酸或苹果酸瓦作处理下油菜根系的形态指标及叶

  4. Studying Photosynthesis by Measuring Fluorescence

    Science.gov (United States)

    Sanchez, Jose Francisco; Quiles, Maria Jose

    2006-01-01

    This paper describes an easy experiment to study the absorption and action spectrum of photosynthesis, as well as the inhibition by heat, high light intensity and the presence of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on the photosynthetic process. The method involves measuring the chlorophyll fluorescence emitted by intact…

  5. Plankton studies in San Francisco Bay; I, Chlorophyll distributions and hydrographic properties, July 1977-December 1979

    Science.gov (United States)

    Alpine, Andrea E.; Cloern, James E.; Cole, Brian E.

    1981-01-01

    This report summarizes the distribution of phytoplankton biomass and selected hydrographic properties measured in the San Francisco Bay Estuary, on a near-monthly basis, from July 1977 through December 1979. Parameters measured were: chlorophyll a, phaeopigments, in-vivo fluorescence, turbidity, size distribution of phytoplankton, salinity and temperature. (USGS)

  6. Modeling hyperspectral observations of vegetation fluorescence from photosystem level to top-of-atmosphere radiance spectra

    Science.gov (United States)

    Verhoef, W.

    2011-12-01

    In support of the candidate ESA mission FLEX, models have been developed to simulate vegetation chlorophyll fluorescence and its observation on the level of single leaves, the canopy and from space. The Fluspect model is based on the PROSPECT leaf model and includes an additional module which calculates the excitation-fluorescence matrix for both sides of the leaf by means of an efficient doubling algorithm. Fluorescence spectra for white incident light, and of course the spectra of reflectance and transmittance, are computed as well. The FluorSAIL model is a numerical variant of SAIL which calculates top-of-canopy fluorescent radiance in the direction of viewing for given incident radiation spectra from the sun and the sky, obtained from the MODTRAN radiative transfer code. In a recent version called FluorSAIL3, high spectral resolution data (0.1 nm) from MODTRAN5 (beta) are used by the model to simulate observations by the candidate FLEX mission. The model computes the directional canopy reflectance with and without fluorescence for the given incident radiation spectra obtained from MODTRAN and the results have been used to evaluate several algorithms for the retrieval of fluorescence from the apparent reflectance signal. In this contribution emphasis will be on the detection of the fluorescence signal, the dependence of fluorescence observations on leaf chlorophyll content and other PROSPECT parameters, canopy structure, and observational conditions, including the properties of the atmosphere. In addition, some attention is paid to the definition of fluorescence quantum efficiencies at photosystem level, leaf level, and canopy level. This is important for the study of the relation between canopy fluorescence and actual photosynthesis. From the simulations it can be concluded that the interpretation of the fluorescence signal is complex, and probably the comparison of actual observations of spectra of fluorescence and reflectance with spectra simulated by a

  7. Green Fluorescent Protein (GFP)-tagged Cysteine-rich Domains from Protein Kinase C as Fluorescent Indicators for Diacylglycerol Signaling in Living Cells

    OpenAIRE

    Oancea, Elena; Teruel, Mary N.; Quest, Andrew F.G.; Meyer, Tobias

    1998-01-01

    Cysteine-rich domains (Cys-domains) are ∼50–amino acid–long protein domains that complex two zinc ions and include a consensus sequence with six cysteine and two histidine residues. In vitro studies have shown that Cys-domains from several protein kinase C (PKC) isoforms and a number of other signaling proteins bind lipid membranes in the presence of diacylglycerol or phorbol ester. Here we examine the second messenger functions of diacylglycerol in living cells by monitoring the membrane tra...

  8. Research Resource: Real-Time Analysis of Somatostatin and Dopamine Receptor Signaling in Pituitary Cells Using a Fluorescence-Based Membrane Potential Assay.

    Science.gov (United States)

    Günther, Thomas; Culler, Michael; Schulz, Stefan

    2016-04-01

    Stable somatostatin analogues and dopamine receptor agonists are the mainstay for the pharmacological treatment of functional pituitary adenomas; however, only a few cellular assays have been developed to detect receptor activation of novel compounds without disrupting cells to obtain the second messenger content. Here, we adapted a novel fluorescence-based membrane potential assay to characterize receptor signaling in a time-dependent manner. This minimally invasive technique provides a robust and reliable read-out for ligand-induced receptor activation in permanent and primary pituitary cells. The mouse corticotropic cell line AtT-20 endogenously expresses both the somatostatin receptors 2 (sst2) and 5 (sst5). Exposure of wild-type AtT-20 cells to the sst2- and sst5-selective agonists BIM-23120 and BIM-23268, respectively, promoted a pertussis toxin- and tertiapin-Q-sensitive reduction in fluorescent signal intensity, which is indicative of activation of G protein-coupled inwardly rectifying potassium (GIRK) channels. After heterologous expression, sst1, sst3, and sst4 receptors also coupled to GIRK channels in AtT-20 cells. Similar activation of GIRK channels by dopamine required overexpression of dopamine D2 receptors (D2Rs). Interestingly, the presence of D2Rs in AtT-20 cells strongly facilitated GIRK channel activation elicited by the sst2-D2 chimeric ligand BIM-23A760, suggesting a synergistic action of sst2 and D2Rs. Furthermore, stable somatostatin analogues produced strong responses in primary pituitary cultures from wild-type mice; however, in cultures from sst2 receptor-deficient mice, only pasireotide and somatoprim, but not octreotide, induced a reduction in fluorescent signal intensity, suggesting that octreotide mediates its pharmacological action primarily via the sst2 receptor. PMID:26967369

  9. Excitation energy transfer between chlorophyll a and chlorophyll b obtained from fluorescence meaeurment's

    OpenAIRE

    Szurkowski, J.; Hotchandanl, S.; Leblanc, R M; Frąckowiak, D.

    1986-01-01

    Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej naukę.

  10. 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;...

  11. Is It Possible to Distinguish Between Dust and Salt Aerosol Over Waters with Unknown Chlorophyll Concentrations Using Spectral Remote Sensing?

    Science.gov (United States)

    Levy, R. C.; Kaufman, Y. J.

    1999-01-01

    Atmospheric aerosol has uncertain impacts on the global climate system, as well as on atmospheric and bio-geo-chemical processes of regional and local scales. EOS-MODIS is one example of a satellite sensor designed to improve understanding of the aerosols' type, size and distribution at all temporal and spatial scales. Ocean scientists also plan to use data from EOS-MODIS to assess the temporal and spatial coverage of in-water chlorophyll. MODIS is the first sensor planned to observe the combined ocean-atmosphere system with a wide spectral range (from 410 to 2200 nm). Dust aerosol and salt aerosol have similar spectral signals for wavelengths longer than 550 nm, but because dust selectively absorbs blue light, they have divergent signals in the blue wavelength regions (412 to 490 nm). Chlorophyll also selectively absorbs blue radiation, so that varying chlorophyll concentrations produces a highly varying signal in the blue regions, but less variability in the green, and almost no signal in the red to mid-infrared regions. Thus, theoretically, it may be difficult to differentiate dust and salt in the presence of unknown chlorophyll in the ocean. This study attempts to address the cases in which aerosol and chlorophyll signals can and cannot be separated. For the aerosol spectra, we use the aerosol lookup table from the operational MODIS aerosol-over-ocean algorithm, and for chlorophyll spectra, we use the SeaBAM data set (created for SeaWiFS). We compare the signals using Principal Component Analysis and attempt to retrieve both chlorophyll and aerosol properties using a variant of the operational MODIS aerosol-over-ocean algorithm. Results show that for small optical depths, less than 0.5, it is not possible to differentiate between dust and salt and to determine the chlorophyll concentration at the same time. For larger aerosol optical depths, the chlorophyll signals are comparatively insignificant, and we can hope to distinguish between dust and salt.

  12. Novel fluorescent ELISA for the sensitive detection of zearalenone based on H2O2-sensitive quantum dots for signal transduction.

    Science.gov (United States)

    Zhan, Shengnan; Huang, Xiaolin; Chen, Rui; Li, Juan; Xiong, Yonghua

    2016-09-01

    A direct competitive fluorescent enzyme-linked immunosorbent assay (ELISA) was developed for the detection of zearalenone (ZEN) using ZEN labeled catalase (CAT) as a competing antigen with H2O2-sensitive CdTe quantum dots (QDs) for signal transduction. The novel fluorescent ELISA showed very high sensitivity for ZEN detection because it combined the high catalytic activity of CAT to H2O2 and H2O2-sensitive property of QDs. Under optimal conditions, the developed method showed a good dynamic linear detection for ZEN in the range of 2.4pg/mL to 1.25ng/mL with a detection limit of 4.1pg/mL. The median inhibition concentration (IC50) of ZEN was 75pg/mL, which was approximately 17-fold lower than that of horseradish peroxidase-based conventional ELISA. Moreover, our developed method also showed a high reproducibility and an excellent selectivity. In brief, the novel fluorescent ELISA shows great potential for the sensitive and economic detection of mycotoxins and other analytes in food analysis, clinical diagnosis and environmental monitoring. PMID:27343577

  13. 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...

  14. 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...

  15. Sensitive aptamer-based fluorescence polarization assay for mercury(II) ions and cysteine using silver nanoparticles as a signal amplifier

    International Nuclear Information System (INIS)

    We report here a signal amplifying strategy to construct polarization aptamer probes for small molecules. The method is based on the use of silver nanoparticles acting as a fluorescence polarization signal amplifier. It was applied to the sensitive and selective detection of the two model analytes mercury (II) and cysteine. The aptamer probes were conjugated to CdTe-CdS quantum dots and are shown to work well for both analytes. The analytical range for Hg(II) is from 10 nM to 0.4 μM, and the limit of detection is 6.6 nM. The respective range for cysteine is from 20 nM to 0.7 μM, and the LOD is 11 nM. (author)

  16. Ultraviolet radiation effects on fruit surface respiration and chlorophyll fluorescence

    Science.gov (United States)

    High-value fruit crops are exposed to a range of environmental conditions that can reduce fruit quality. Solar injury (SI) or sunburn is a common disorder in tropical, subtropical and temperate climates and is related to: 1) high fruit surface temperature, 2) high visible light intensity, and 3) ul...

  17. Chlorophyll fluorescence as a marker for herbicide mechanisms of action

    Science.gov (United States)

    Photosynthesis is the single most important source of O2 and organic chemical energy necessary to support all non-autotrophic life forms. Plants compartmentalize this elaborate biochemical process within chloroplasts in order to safely harness the power of solar energy and convert it into usable ch...

  18. Kinetic imaging of chlorophyll fluorescence using modulated light

    Czech Academy of Sciences Publication Activity Database

    Nedbal, Ladislav; Soukupová, Julie; Kaftan, David; Whitmarsh, J.; Trtílek, M.

    2000-01-01

    Roč. 66, 1 - 2 (2000), s. 3-12. ISSN 0166-8595 Institutional research plan: CEZ:AV0Z6087904 Keywords : herbicide * instrumentation * mutant selection Subject RIV: BO - Biophysics Impact factor: 1.633, year: 2000

  19. A Hyperspectral Multispectral Algorithm for Fluorescence and Reflectance Retrieval from Space

    Science.gov (United States)

    Mazzoni, Marina; Falorni, Pierluigi; Verhoef, Wouter

    2010-12-01

    A model inversion by optimization was investigated for very small (less than 1% of the total sensor radiance) fluorescence signal retrievals from space. For this reason, the retrieval was done in special spectral regions (atmospheric absorption bands) in which solar radiation is attenuated. For the simulations we considered a complete model system of coupled radiative soil-canopy radiation. A four-stream atmospheric flux (i.e. direct solar flux, diffuse downward flux, diffuse upward flux, direct observed flux) at very high spectral resolution (0.1 cm-1) was used for the retrieval of the canopy chlorophyll fluorescence. Only one mathematical function was contemporarily used to fit fluorescence in both the oxygen A and B windows (multispectral fitting).

  20. Novel signal-amplifying fluorescent nanofibers for naked-eye-based ultrasensitive detection of buried explosives and explosive vapors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ying; La, Anthony; Ding, Yu; Liu, Yixin; Lei, Yu [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT (United States)

    2012-09-11

    A novel electrospun fluorescent nanofiberous membrane with a function like ''molecular wires'' was developed via electrospinning for the detection of ultra-trace nitro explosive vapors and buried explosives by naked eye under UV excitation. The high binding affinity between the electron-deficient nitro explosives and the sensing film results in a rapid, dramatic quenching in its fluorescence emission. A wide spectrum of nitro explosives, in particular, TNT, Tetryl, RDX, PETN and HMX could be ''visually'' detected at their sub-equilibrium vapors (less than 10 ppb, 74 ppt, 5 ppt, 7 ppt and 0.1 ppt, respectively) released from 1 ng explosives residues. Such outstanding sensing performance could be attributed to the proposed ''sandwich-like'' conformation between pyrene and phenyl pendants of PS which may allow efficient long-range energy migration similar to ''molecular wire'', thus achieving amplified fluorescence quenching. Its application for the detection of buried explosives in soil by naked eye was also demonstrated, indicating its potential application for landmine mapping. To the best of our knowledge, this is the first report about the detection of buried explosives without the use of any advanced analytical instrumentation. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)