Science.gov

Sample records for chlorophyll fluorescence estimation

  1. [Chlorophyll fluorescence induction and estimation of plant resistance to stress factors].

    PubMed

    Nesterenko, T V; Tikhomirov, A A; Shikhov, V N

    2007-01-01

    The usage of chlorophyll fluorescence induction (CFI) for estimating various types of plant resistance (primary, general, initial, adaptive) to stress factors is reviewed. The necessity of ontogenetic approach (considering the age-specific properties of the photosynthetic apparatus) in determining general and adaptive resistance of plants to prolonged action of stress factors by the CFI method is argued. In the plant Cucumbis sativus L., the possibility is shown of using age-specific qualitative and quantitative traits of leaf CFI (changes in the shape of chlorophyll fluorescence induction curves and in the dynamics of CFI parameters in the course of leaf ontogeny) for comparative study of differences between fully active and stressed plants. Possible criteria are suggested for estimating the effect of outer stress factors by the presence or absence of a steady-state phase in the dynamics of CFI parameters during leaf ontogeny. It is also suggested to use the duration of the steady-state phase following the termination of leaf growth (estimated by the dynamics of the slow phase of CFI as the ratio of fluorescence intensity at the peak P and the steady-state fluorescence intensity, Fp/Fs, or as the viability index Rfd) and the variability of CFI parameters during this period as qualitative estimates of plant resistance to prolonged action of stress factors.

  2. Simplified, rapid, and inexpensive estimation of water primary productivity based on chlorophyll fluorescence parameter Fo.

    PubMed

    Chen, Hui; Zhou, Wei; Chen, Weixian; Xie, Wei; Jiang, Liping; Liang, Qinlang; Huang, Mingjun; Wu, Zongwen; Wang, Qiang

    2017-04-01

    Primary productivity in water environment relies on the photosynthetic production of microalgae. Chlorophyll fluorescence is widely used to detect the growth status and photosynthetic efficiency of microalgae. In this study, a method was established to determine the Chl a content, cell density of microalgae, and water primary productivity by measuring chlorophyll fluorescence parameter Fo. A significant linear relationship between chlorophyll fluorescence parameter Fo and Chl a content of microalgae, as well as between Fo and cell density, was observed under pure-culture conditions. Furthermore, water samples collected from natural aquaculture ponds were used to validate the correlation between Fo and water primary productivity, which is closely related to Chl a content in water. Thus, for a given pure culture of microalgae or phytoplankton (mainly microalgae) in aquaculture ponds or other natural ponds for which the relationship between the Fo value and Chl a content or cell density could be established, Chl a content or cell density could be determined by measuring the Fo value, thereby making it possible to calculate the water primary productivity. It is believed that this method can provide a convenient way of efficiently estimating the primary productivity in natural aquaculture ponds and bringing economic value in limnetic ecology assessment, as well as in algal bloom monitoring. Copyright © 2017 Elsevier GmbH. All rights reserved.

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  4. Improving the estimation of terrestrial gross primary productivity by downscaling global sun-induced chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    Cescatti, A.; Duveiller, G.

    2015-12-01

    The synoptic nature of satellite remote sensing makes this technique a key tool to contribute to estimating the amount of Carbon fixed by vegetation at global scale. From the various types of information that can be derived from space, the recent capacity to create global datasets of sun-induced chlorophyll fluorescence (SIF) may prove to be a game-changer. SIF is a signal emitted by the photosynthetic machinery itself that, under the illumination conditions in which it can be estimated by satellite, has been shown to be proportional to gross primary productivity (GPP). However, this relationship is dependent on vegetation types that are typically spatially mixed at the coarse spatial resolution of SIF datasets (at best 0.5°), which in turn is a consequence of the complexity of the SIF retrieval itself. This study demonstrates how 0.5° SIF derived from GOME-2 data can be downscaled to a more adequate spatial resolution of 0.05° by combining 3 explanatory biophysical variables derived from the MODIS sensor (NDVI, land surface temperature and evapotranspiration) under a semi-empirical light-use efficiency framework. The finer spatial resolution results in a cleaner signal when aggregating it per land cover type. The signal is also better correlated in time with GPP estimated from flux towers, reaching the same level of performance than global GPP products calibrated on such flux towers and driven by meteorological and remote sensing variables (other than SIF). Establishing linear relationships between SIF and flux-tower GPP at vegetation type level allows to estimate values of global terrestrial vegetation gross productivity that have different magnitude but similar temporal patterns as other GPP products. Based on downscaled SIF, the mean global GPP values over the period 2007 to 2013 are (for deciduous broadleaf and mixed forests) 13.7, (for evergreen needleleaf forests) 2.5, (for grasslands) 12.5 and (savannahs and woody savannas) 36.8 Pg of Carbon per year.

  5. Rapid field estimation of biochemical oxygen demand in a subtropical eutrophic urban lake with chlorophyll a fluorescence.

    PubMed

    Xu, Zhen; Xu, Y Jun

    2015-01-01

    Development of a technique for rapid field estimation of biochemical oxygen demand (BOD) is necessary for cost-effective monitoring and management of urban lakes. While several studies reported the usefulness of laboratory tryptophan-like fluorescence technique in predicting 5-day BOD (BOD₅) of wastewater and leachates, little is known about the predictability of field chlorophyll fluorescence measurements for BOD of urban lake waters that are constantly exposed to the mixture of chemical compounds. This study was conducted to develop a numeric relationship between chlorophyll a fluorescence and BOD for a eutrophic urban lake that is widely representative of lake water conditions in the subtropical southern USA. From October 2012 to September 2013, in situ measurements at the studied lake were made every 2 weeks on chlorophyll a fluorescence and other water quality parameters including water temperature, pH, dissolved oxygen, and specific conductivity. Water samples were taken for 5-day BOD and 10-day BOD (BOD₁₀) analysis with and without incubation. The results showed a clear seasonal trend of both BOD measurements being high during the summer and low during the winter. There was a linear, positive relationship between chlorophyll a fluorescence and BOD, and the relationship appeared to be stronger with the 10-day BOD (r(2) = 0.83) than with the 5-day BOD (r(2) = 0.76). BOD dropped each day with declining chlorophyll a fluorescence, suggesting that die-off of phytoplankton has been the main consumption of oxygen in the studied lake. Ambient conditions such as rainfall and water temperature may have partially affected BOD variation.

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

    PubMed Central

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

    2015-01-01

    This paper illustrates the possibility of measuring chlorophyll (Chl) content and Chl fluorescence parameters by the solar-induced Chl fluorescence (SIF) method using the Fraunhofer line depth (FLD) principle, and compares the results with the standard measurement methods. A high-spectral resolution HR2000+ and an ordinary USB4000 spectrometer were used to measure leaf reflectance under solar and artificial light, respectively, to estimate Chl fluorescence. Using leaves of Capsicum annuum cv. ‘Sven’ (paprika), the relationships between the Chl content and the steady-state Chl fluorescence near oxygen absorption bands of O2B (686nm) and O2A (760nm), measured under artificial and solar light at different growing stages of leaves, were evaluated. The Chl fluorescence yields of ΦF 686nm/ΦF 760nm ratios obtained from both methods correlated well with the Chl content (steady-state solar light: R2 = 0.73; artificial light: R2 = 0.94). The SIF method was less accurate for Chl content estimation when Chl content was high. The steady-state solar-induced Chl fluorescence yield ratio correlated very well with the artificial-light-induced one (R2 = 0.84). A new methodology is then presented to estimate photochemical yield of photosystem II (ΦPSII) from the SIF measurements, which was verified against the standard Chl fluorescence measurement method (pulse-amplitude modulated method). The high coefficient of determination (R2 = 0.74) between the ΦPSII of the two methods shows that photosynthesis process parameters can be successfully estimated using the presented methodology. PMID:26071530

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

    PubMed

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

    2015-09-01

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

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

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

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

    2014-12-01

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

  10. [Fluorescence characteristics of different chlorophyll a concentration in Lake Taihu].

    PubMed

    Li, Li; Yin, Qiu; Gong, Cai-Lan; Xu, Hua; Chen, Li-Xiong

    2011-01-01

    The spectral reflectance and water qualities of 27 stations were acquired in the lake Taihu during the months from May to August, 2008 when blue algal bloomed. Based on the fluorescence characteristics analysis of different chlorophyll a concentration, it was obvious that the position and height of fluorescence peak both have a positive correlation with chlorophyll a concentration, and the correlation coefficients between chlorophyll a concentration and position and half width of fluorescence peak are larger than those of the reference baseline and the normalized height of fluorescence. Estimating of chlorophyll a concentration in case 2 water using fluorescence characteristics is obviously better than the empirical algorithm based on blue to green ratio. Moreover, the common algorithm based on near infrared band to red band ratio is essentially consistent with the normalized height method.

  11. Chlorophyll Fluorescence and Dynamic Xanthophyll Reflectance as Methods to Estimate Photosynthesis with Remote Sensors - A Modelling Approach

    NASA Astrophysics Data System (ADS)

    Vilfan, N.; Van der Tol, C.; Verhoef, W.

    2016-12-01

    Chlorophyll fluorescence (ChlF) has been proven valuable in studying the dynamics of photosynthesis: together with the photochemical reflectance index (PRI), which reflects the changes in reflectance around 535 nm due to the xanthophyll cycle effect, it offers a powerful way to non-destructively quantify plant photosynthetic and dissipation activity from leaf to potentially global scale. We present an extended simulation model, Fluspect, for the transfer of light within the leaf as a function of its pigment contents and structure. Output of the model are reflectance and transmittance spectra of the leaf as well as ChlF spectra. From ChlF spectra, fluorescence quantum efficiency parameters (η) of photosystems I and II can be retrieved. Moreover, we extended and parameterized Fluspect by including a physically based description of the dynamic xanthophyll reflectance (XR). We introduced a new, retrievable parameter, V2Z, for the status of the XR. Finally, we combined the model Fluspect with a simple enzyme kinetics model of photosynthesis. In this study, we explore the combined model by using relations among photochemical quenching (PQ), non-photochemical quenching (NPQ), V2Z and η. We explore these relationships by using multiple available datasets, where measurements were by different combinations of the following methods: (1) hyperspectral leaf reflectance in visible to NIR region together with ChlF spectra, (2) gas exchange, and (3) Pulse Amplitude Modulated (PAM) fluorescence. The aim of the study is to explore the relationships between the two fundamentally different components, namely the transfer of light within the leaf and the enzyme kinetics of photosynthesis. Moreover, it is now possible to simulate dynamic xanthophyll reflectance and chlorophyll fluorescence quenching simultaneously, which is relevant for the remote sensing of photosynthesis.

  12. Bowel perforation detection using metabolic fluorescent chlorophylls

    NASA Astrophysics Data System (ADS)

    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.

  13. Rethinking Chlorophyll Responses To Stress: Fluorescence and Flectance Remote Sensing in a Coastal Environment

    DTIC Science & Technology

    2010-11-15

    fluorescence emission of vegetation for mapping vegetation stress as chlorophyll content and/or carotenoid content changes. 1. REPORT DATE (DD-MM-YYYY...that estimate fluorescence emission of vegetation for mapping vegetation stress as chlorophyll content and/or carotenoid content changes...not related to changes in chlorophyll content or the carotenoids /chlorophyll ratio. PRI is an indicator of chronic salinity stress and may be used as

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

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

    2017-02-01

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

  16. Evaluating a new method to estimate the rate of leaf respiration in the light by analysis of combined gas exchange and chlorophyll fluorescence measurements.

    PubMed

    Yin, Xinyou; Sun, Zhouping; Struik, Paul C; Gu, Junfei

    2011-06-01

    Day respiration (R(d)) is an important parameter in leaf ecophysiology. It is difficult to measure directly and is indirectly estimated from gas exchange (GE) measurements of the net photosynthetic rate (A), commonly using the Laisk method or the Kok method. Recently a new method was proposed to estimate R(d) indirectly from combined GE and chlorophyll fluorescence (CF) measurements across a range of low irradiances. Here this method is tested for estimating R(d) in five C(3) and one C(4) crop species. Values estimated by this new method agreed with those by the Laisk method for the C(3) species. The Laisk method, however, is only valid for C(3) species and requires measurements at very low CO(2) levels. In contrast, the new method can be applied to both C(3) and C(4) plants and at any CO(2) level. The R(d) estimates by the new method were consistently somewhat higher than those by the Kok method, because using CF data corrects for errors due to any non-linearity between A and irradiance of the used data range. Like the Kok and Laisk methods, the new method is based on the assumption that R(d) varies little with light intensity, which is still subject to debate. Theoretically, the new method, like the Kok method, works best for non-photorespiratory conditions. As CF information is required, data for the new method are usually collected using a small leaf chamber, whereas the Kok and Laisk methods use only GE data, allowing the use of a larger chamber to reduce the noise-to-signal ratio of GE measurements.

  17. Evaluating a new method to estimate the rate of leaf respiration in the light by analysis of combined gas exchange and chlorophyll fluorescence measurements

    PubMed Central

    Yin, Xinyou; Sun, Zhouping; Struik, Paul C.; Gu, Junfei

    2011-01-01

    Day respiration (Rd) is an important parameter in leaf ecophysiology. It is difficult to measure directly and is indirectly estimated from gas exchange (GE) measurements of the net photosynthetic rate (A), commonly using the Laisk method or the Kok method. Recently a new method was proposed to estimate Rd indirectly from combined GE and chlorophyll fluorescence (CF) measurements across a range of low irradiances. Here this method is tested for estimating Rd in five C3 and one C4 crop species. Values estimated by this new method agreed with those by the Laisk method for the C3 species. The Laisk method, however, is only valid for C3 species and requires measurements at very low CO2 levels. In contrast, the new method can be applied to both C3 and C4 plants and at any CO2 level. The Rd estimates by the new method were consistently somewhat higher than those by the Kok method, because using CF data corrects for errors due to any non-linearity between A and irradiance of the used data range. Like the Kok and Laisk methods, the new method is based on the assumption that Rd varies little with light intensity, which is still subject to debate. Theoretically, the new method, like the Kok method, works best for non-photorespiratory conditions. As CF information is required, data for the new method are usually collected using a small leaf chamber, whereas the Kok and Laisk methods use only GE data, allowing the use of a larger chamber to reduce the noise-to-signal ratio of GE measurements. PMID:21382918

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

    USDA-ARS?s Scientific Manuscript database

    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...

  19. Remote sensing of chlorophyll fluorescence with GOSAT

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  1. 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

    NASA Astrophysics Data System (ADS)

    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

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  4. Tomato seeds maturity detection system based on chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    Li, Cuiling; Wang, Xiu; Meng, Zhijun

    2016-10-01

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

  5. Contribution of chlorophyll fluorescence to the apparent vegetation reflectance.

    PubMed

    Campbell, P K Entcheva; Middleton, E M; Corp, L A; Kim, M S

    2008-10-15

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

  6. An overview of remote sensing of chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. 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)

    NASA Technical Reports Server (NTRS)

    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

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

    NASA Astrophysics Data System (ADS)

    Rossini, M.; Nedbal, L.; Guanter, L.; Ač, A.; Alonso, L.; Burkart, A.; Cogliati, S.; Colombo, R.; Damm, A.; Drusch, M.; Hanus, J.; Janoutova, R.; Julitta, T.; Kokkalis, P.; Moreno, J.; Novotny, J.; Panigada, C.; Pinto, F.; Schickling, A.; Schüttemeyer, D.; Zemek, F.; Rascher, U.

    2015-03-01

    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 using a novel airborne imaging spectrometer over a grass carpet treated with an herbicide known to inhibit photosynthesis was significantly higher than the corresponding signal from an equivalent untreated grass carpet. The reflectance signal of the two grass carpets was indistinguishable, confirming that the fast dynamic changes in fluorescence emission were related to variations in the functional status of actual photosynthesis induced by herbicide application. Our results from a controlled experiment at the local scale illustrate the potential for the global mapping of terrestrial photosynthesis through space-borne measurements of chlorophyll fluorescence.

  10. Chlorophyll Fluorescence Imaging Uncovers Photosynthetic Fingerprint of Citrus Huanglongbing.

    PubMed

    Cen, Haiyan; Weng, Haiyong; Yao, Jieni; He, Mubin; Lv, Jingwen; Hua, Shijia; Li, Hongye; He, Yong

    2017-01-01

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

  11. Chlorophyll Fluorescence Imaging Uncovers Photosynthetic Fingerprint of Citrus Huanglongbing

    PubMed Central

    Cen, Haiyan; Weng, Haiyong; Yao, Jieni; He, Mubin; Lv, Jingwen; Hua, Shijia; Li, Hongye; He, Yong

    2017-01-01

    Huanglongbing (HLB) is one of the most destructive diseases of citrus, which has posed a serious threat to the global citrus production. This research was aimed to explore the use of chlorophyll fluorescence imaging combined with feature selection to characterize and detect the HLB disease. Chlorophyll fluorescence images of citrus leaf samples were measured by an in-house chlorophyll fluorescence imaging system. The commonly used chlorophyll fluorescence parameters provided the first screening of HLB disease. To further explore the photosynthetic fingerprint of HLB infected leaves, three feature selection methods combined with the supervised classifiers were employed to identify the unique fluorescence signature of HLB and perform the three-class classification (i.e., healthy, HLB infected, and nutrient deficient leaves). Unlike the commonly used fluorescence parameters, this novel data-driven approach by using the combination of the mean fluorescence parameters and image features gave the best classification performance with the accuracy of 97%, and presented a better interpretation for the spatial heterogeneity of photochemical and non-photochemical components in HLB infected citrus leaves. These results imply the potential of the proposed approach for the citrus HLB disease diagnosis, and also provide a valuable insight for the photosynthetic response to the HLB disease. PMID:28900440

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Instrumentation in Developing Chlorophyll Fluorescence Biosensing: A Review

    PubMed Central

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

    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

  15. Quenching of chlorophyll fluorescence by quinones.

    PubMed

    Samuilov, V D; Borisov AYu; Barsky, E L; Borisova, O F; Kitashov, A V

    1998-10-01

    Quinones caused quenching of Chl a fluorescence in native and model systems. Menadione quenched twofold the fluorescence of Chl a and BChl a in pea chloroplasts, chromatophores of purple bacteria, and liposomes at concentrations of 50-80 microM. To obtain twofold quenching in Triton X-100 micelles and in ethanol, the addition of 1.3 mM and 11 mM menadione was required, respectively. A proportional decrease in the lifetime and yield of Chl a fluorescence in chloroplasts, observed as the menadione concentration increased, is indicative of the efficient excitation energy transfer from bulk Chl to menadione. The decrease in the lifetime and yield of fluorescence was close to proportional in liposomes, but not in detergent micelles. The insensitivity of the menadione quenching effect to DCMU in chloroplasts, and similarity of its action in chloroplasts and liposomes indicate that menadione in chloroplasts interacts with antenna Chl, i.e., nonphotochemical quenching of fluorescence occurs.

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

    PubMed

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

    2012-04-01

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

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  19. Effects of bisphenol A on chlorophyll fluorescence in five plants.

    PubMed

    Zhang, Jiazhi; Wang, Lihong; Li, Man; Jiao, Liya; Zhou, Qing; Huang, Xiaohua

    2015-11-01

    The aim of this study was to evaluate the effects of bisphenol A (BPA) on plant photosynthesis and determine whether the photosynthetic response to BPA exposure varies in different plants. Chlorophyll fluorescence techniques were used to investigate the effects of BPA on chlorophyll fluorescence parameters in tomato (Lycopersicum esculentum), lettuce (Lactuca sativa), soybean (Glycine max), maize (Zea mays), and rice (Oryza sativa) seedlings. Low-dose (1.5 or 3.0 mg L(-1)) BPA exposure improved photosystem II efficiency, increased the absorption and conversion efficiency of primary light energy, and accelerated photosynthetic electron transport in each plant, all of which increased photosynthesis. These effects weakened or disappeared after the withdrawal of BPA. High-dose (10.0 mg L(-1)) BPA exposure damaged the photosystem II reaction center, inhibited the photochemical reaction, and caused excess energy to be released as heat. These effects were more evident after the highest BPA dose (17.2 mg L(-1)), but they weakened after the withdrawal of BPA. The magnitude of BPA exposure effects on the chlorophyll fluorescence parameters in the five plants followed the order: lettuce > tomato > soybean > maize > rice. The opposite order was observed following the removal of BPA. In conclusion, the chlorophyll fluorescence response in plants exposed to BPA depended on BPA dose and plant species.

  20. Molecular environments of divinyl chlorophylls in Prochlorococcus and Synechocystis: differences in fluorescence properties with chlorophyll replacement.

    PubMed

    Mimuro, Mamoru; Murakami, Akio; Tomo, Tatsuya; Tsuchiya, Tohru; Watabe, Kazuyuki; Yokono, Makio; Akimoto, Seiji

    2011-05-01

    A marine cyanobacterium, Prochlorococcus, is a unique oxygenic photosynthetic organism, which accumulates divinyl chlorophylls instead of the monovinyl chlorophylls. To investigate the molecular environment of pigments after pigment replacement but before optimization of the protein moiety in photosynthetic organisms, we compared the fluorescence properties of the divinyl Chl a-containing cyanobacteria, Prochlorococcus marinus (CCMP 1986, CCMP 2773 and CCMP 1375), by a Synechocystis sp. PCC 6803 (Synechocystis) mutant in which monovinyl Chl a was replaced with divinyl Chl a. P. marinus showed a single fluorescence band for photosystem (PS) II at 687nm at 77K; this was accompanied with change in pigment, because the Synechocystis mutant showed the identical shift. No fluorescence bands corresponding to the PS II 696-nm component and PS I longer-wavelength component were detected in P. marinus, although the presence of the former was suggested using time-resolved fluorescence spectra. Delayed fluorescence (DF) was detected at approximately 688nm with a lifetime of approximately 29ns. In striking contrast, the Synechocystis mutant showed three fluorescence bands at 687, 696, and 727nm, but suppressed DF. These differences in fluorescence behaviors might not only reflect differences in the molecular structure of pigments but also differences in molecular environments of pigments, including pigment-pigment and/or pigment-protein interactions, in the antenna and electron transfer systems. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Photosynthetic bark: Use of chlorophyll absorption continuum index to estimate Boswellia papyrifera bark chlorophyll content

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    Quantification of chlorophyll content provides useful insight into the physiological performance of plants. Several leaf chlorophyll estimation techniques, using hyperspectral instruments, are available. However, to our knowledge, a non-destructive bark chlorophyll estimation technique is not available. We set out to assess Boswellia papyrifera tree bark chlorophyll content and to provide an appropriate bark chlorophyll estimation technique using hyperspectral remote sensing techniques. In contrast to the leaves, the bark of B. papyrifera has several outer layers masking the inner photosynthetic bark layer. Thus, our interest includes understanding how much light energy is transmitted to the photosynthetic inner bark and to what extent the inner photosynthetic bark chlorophyll activity could be remotely sensed during both the wet and the dry season. In this study, chlorophyll estimation using the chlorophyll absorption continuum index (CACI) yielded a higher R2 (0.87) than others indices and methods, such as the use of single band, simple ratios, normalized differences, and conventional red edge position (REP) based estimation techniques. The chlorophyll absorption continuum index approach considers the increase or widening in area of the chlorophyll absorption region, attributed to high concentrations of chlorophyll causing spectral shifts in both the yellow and the red edge. During the wet season B. papyrifera trees contain more bark layers than during the dry season. Having less bark layers during the dry season (leaf off condition) is an advantage for the plants as then their inner photosynthetic bark is more exposed to light, enabling them to trap light energy. It is concluded that B. papyrifera bark chlorophyll content can be reliably estimated using the chlorophyll absorption continuum index analysis. Further research on the use of bark signatures is recommended, in order to discriminate the deciduous B. papyrifera from other species during the dry season.

  2. Frequently asked questions about chlorophyll fluorescence, the sequel.

    PubMed

    Kalaji, Hazem M; Schansker, Gert; Brestic, Marian; Bussotti, Filippo; Calatayud, Angeles; Ferroni, Lorenzo; Goltsev, Vasilij; Guidi, Lucia; Jajoo, Anjana; Li, Pengmin; Losciale, Pasquale; Mishra, Vinod K; Misra, Amarendra N; Nebauer, Sergio G; Pancaldi, Simonetta; Penella, Consuelo; Pollastrini, Martina; Suresh, Kancherla; Tambussi, Eduardo; Yanniccari, Marcos; Zivcak, Marek; Cetner, Magdalena D; Samborska, Izabela A; Stirbet, Alexandrina; Olsovska, Katarina; Kunderlikova, Kristyna; Shelonzek, Henry; Rusinowski, Szymon; Bąba, Wojciech

    2017-04-01

    Using chlorophyll (Chl) a fluorescence many aspects of the photosynthetic apparatus can be studied, both in vitro and, noninvasively, in vivo. Complementary techniques can help to interpret changes in the Chl a fluorescence kinetics. Kalaji et al. (Photosynth Res 122:121-158, 2014a) addressed several questions about instruments, methods and applications based on Chl a fluorescence. Here, additional Chl a fluorescence-related topics are discussed again in a question and answer format. Examples are the effect of connectivity on photochemical quenching, the correction of F V /F M values for PSI fluorescence, the energy partitioning concept, the interpretation of the complementary area, probing the donor side of PSII, the assignment of bands of 77 K fluorescence emission spectra to fluorescence emitters, the relationship between prompt and delayed fluorescence, potential problems when sampling tree canopies, the use of fluorescence parameters in QTL studies, the use of Chl a fluorescence in biosensor applications and the application of neural network approaches for the analysis of fluorescence measurements. The answers draw on knowledge from different Chl a fluorescence analysis domains, yielding in several cases new insights.

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

    PubMed Central

    van der Tol, C; Berry, J A; Campbell, P K E; 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 xanthophyll pigment concentrations. The relationship was quantified after analyzing data sets of pulse amplitude modulated measurements of chlorophyll fluorescence and gas exchange of leaves of different species exposed to different levels of light, CO2, temperature, nitrogen fertilization treatments, and drought. We used this relationship in a photosynthesis model. The coupled model enabled us to quantify the relationships between steady state chlorophyll fluorescence yield, electron transport rate, and photosynthesis in leaves under different environmental conditions. Key Points Light saturation of photosynthesis determines quenching of leaf fluorescence We incorporated steady state leaf fluorescence in a photosynthesis model PMID:27398266

  4. Estimate chlorophyll a and POC concentrations in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Haëntjens, N.; Boss, E.; Talley, L. D.

    2016-02-01

    The Southern Ocean Carbon and Climate Observations and Modeling project (SOCCOM) is deploying hundreds of profiling floats with (NASA-funded) bio-optical sensors in the Southern Ocean. The optical sensor measure chlorophyll fluorescence (Ex/Em 470/685nm) and the backscattering coefficient at 700nm, which are routinely as proxies for chlorophyll a (chl-a) and particulate organic carbon (POC) concentrations. To assess the quality of the chl-a and POC derived from the float's measurements we compare them with chl-a and POC samples collected near the times the floats were deployed. Through the life of a float, we also compare its measurements to estimates of chl-a and the backscattering coefficient derived from remotely sensed ocean color. In addition, on most cruises where floats are deployed, a `golden' sensor is deployed on the CTD rosette for cross-calibration between floats. For fluorescence measurements done when there is significant irradiance in the upper ocean we correct for non-photochemical quenching of fluorescence with an average of Xing et al. (2012) and Sackmann et al.'s (2008) methods. To date we have found the backscattering measurement to be consistent with previous studies while chl-a estimated with fluorescence is significantly over estimated when using the manufacturer calibration (factor of 7 relative to HPLC, 3.5 relative to local ocean color algorithms). We hope that our work will provide for an unprecedented, quality-controlled, dataset of chl-a and POC for the Southern Ocean to be used in biogeochemical studies.

  5. Quenching of chlorophyll fluorescence induced by silver nanoparticles.

    PubMed

    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

    2016-11-05

    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.

  6. Quenching of chlorophyll fluorescence induced by silver nanoparticles

    NASA Astrophysics Data System (ADS)

    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 100 nm 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 678 nm. 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.

  7. Chlorophyll fluorescence control in microalgae by biogenic guanine crystals

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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.

  9. Metal-enhanced fluorescence of chlorophylls in light-harvesting complexes coupled to silver nanowires.

    PubMed

    Kowalska, Dorota; Krajnik, Bartosz; Olejnik, Maria; Twardowska, Magdalena; Czechowski, Nikodem; Hofmann, Eckhard; Mackowski, Sebastian

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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 xanthophyll pigment concentrations. The relationship was quantified after analyzing data sets of pulse amplitude modulated measurements of chlorophyll fluorescence and gas exchange of leaves of different species exposed to different levels of light, CO2, temperature, nitrogen fertilization treatments, and drought. We used this relationship in a photosynthesis model. The coupled model enabled us to quantify the relationships between steady state chlorophyll fluorescence yield, electron transport rate, and photosynthesis in leaves under different environmental conditions.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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 xanthophyll pigment concentrations. The relationship was quantified after analyzing data sets of pulse amplitude modulated measurements of chlorophyll fluorescence and gas exchange of leaves of different species exposed to different levels of light, CO2, temperature, nitrogen fertilization treatments, and drought. We used this relationship in a photosynthesis model. The coupled model enabled us to quantify the relationships between steady state chlorophyll fluorescence yield, electron transport rate, and photosynthesis in leaves under different environmental conditions.

  12. Modelling canopy scale solar induced chlorophyll fluorescence simulated by the three dimensional radiative transfer model

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Nagai, S.; Inoue, T.; Yang, W.; Ichii, K.

    2014-12-01

    Recent studies show that the vegetation canopy scale sun-induced chlorophyll fluorescence (SIF) can be observed from satellite. To understand how the canopy scale bidirectional fluorescence observations are related to three-dimensional fluorescence distribution within a plant canopy, it is necessary to evaluate canopy scale fluorescence emission using a detailed plant canopy radiative transfer model. In this study, we developed a three-dimensional plant canopy radiative transfer model that can simulate the bidirectional chlorophyll fluorescence radiance and show several preliminary results of fluorescence distribution at the tree level. To simulate the three dimensional variations in chlorophyll fluorescence from trees, we measured tree structures using a terrestrial LiDAR instrument. The measurements were conducted in Yokohama, Japan (35°22'49" N 139°37'29" E). Three Japanese cherry trees (Cerasus Speciosa) were chosen for our study (Figure 1). Leaf-level sun-induced chlorophyll fluorescence (SIF) is also necessary as an input of radiative transfer model. To measure the leaf-level SIF, we used high spectral resolution spectroradiometer (HR 4000, Ocean Optics Inc. USA). The spectral resolution of this instrument is 0.05 nm (full width half maximum). The spectral range measured was 720 to 780 nm. From the spectral radiance measurements, we estimated SIF using the three band Fraunhofer Line Depth (3FLD) method. The effect of solar and view zenith angles, multiple scattering depends on many factors such as back ground reflectance, leaf reflectance transmittance and landscape structures. To understand how the SIF from both sparse and dense forest stands vary with sun and view angles and optical variables, it is necessary to conduct further sensitivity analysis. Radiative transfer simulation will help understand SIF emission at variety of forest canopy cases.

  13. [Estimation of canopy chlorophyll content using hyperspectral data].

    PubMed

    Dong, Jing-Jing; Wang, Li; Niu, Zheng

    2009-11-01

    Many researches have developed models to estimate chlorophyl content at leaf and canopy level, but they were species-specific. The objective of the present paper was to develop a new model. First, canopy reflectance was simulated for different species and different canopy architecture using radiative transfer models. Based on the simulated canopy reflectance, the relationship between canopy reflectance and canopy chlorophyll content was studied, and then a chlorophyll estimation model was built using the method of spectral index. The coefficient of determination (R2) between spectral index based model and canopy chlorophyll content reached 0.75 for simulated data. To investigate the applicability of this chlorophyll model, the authors chose a field sample area in Gansu Province to carry out the measurement of leaf chlorophyll content, canopy reflectance and other parameters. Besides, the authors also ordered the synchronous Hyperion data, a hyperspectral image with a spatial resolution of 30 m. Canopy reflectance from field measurment and reflectance from Hyperion image were respectively used as the input parameter for the chlorophyll estimation model. Both of them got good results, which indicated that the model could be used for accurate canopy chlorophyll estimation using canopy reflectance. However, while using spaceborne hyperspectral data to estimate canopy chlorophyll content, good atmospheric correction is required.

  14. Photo-physiological variability in phytoplankton chlorophyll fluorescence and assessment of chlorophyll concentration.

    PubMed

    Chekalyuk, Alexander; Hafez, Mark

    2011-11-07

    Photo-physiological variability of in vivo chlorophyll fluorescence (CF) per unit of chlorophyll concentration (CC) is analyzed using a biophysical model to improve the accuracy of CC assessments. Field measurements of CF and photosystem II (PSII) photochemical yield (PY) with the Advanced Laser Fluorometer (ALF) in the Delaware and Chesapeake Bays are analyzed vs. high-performance liquid chromatography (HPLC) CC retrievals. It is shown that isolation from ambient light, PSII saturating excitation, optimized phytoplankton exposure to excitation, and phytoplankton dark adaptation may provide accurate in vivo CC fluorescence measurements (R2 = 0.90-0.95 vs. HPLC retrievals). For in situ or flow-through measurements that do not allow for dark adaptation, concurrent PY measurements can be used to adjust for CF non-photochemical quenching (NPQ) and improve the accuracy of CC fluorescence assessments. Field evaluation has shown the NPQ-invariance of CF/PY and CF(PY-1-1) parameters and their high correlation with HPLC CC retrievals (R2 = 0.74-0.96), while the NPQ-affected CF measurements correlated poorly with CC (R2 = -0.22).

  15. Laser and sunlight-induced fluorescence from chlorophyll pigments

    NASA Technical Reports Server (NTRS)

    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.

  16. Laser and sunlight-induced fluorescence from chlorophyll pigments

    NASA Technical Reports Server (NTRS)

    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.

  17. Chlorophyll fluorescence, photochemical reflective index and normalized difference vegetative index during plant senescence.

    PubMed

    Cordon, Gabriela; Lagorio, M Gabriela; Paruelo, José M

    2016-07-20

    The relationship between the Photochemical Reflectance Index (PRI), Normalized Difference Vegetation Index (NDVI) and chlorophyll fluorescence along senescence was investigated in this work. Reflectance and radiance measurements were performed at canopy level in grass species presenting different photosynthetic metabolism: Avena sativa (C3) and Setaria italica (C4), at different stages of the natural senescence process. Sun induced-chlorophyll fluorescence at 760nm (SIF760) and the apparent fluorescence yield (SIF760/a, with a=irradiance at time of measurement) were extracted from the radiance spectra of canopies using the Fraunhofer Line Discrimination-method. The photosynthetic parameters derived from Kautsky kinetics and pigment content were also calculated at leaf level. Whilst stand level NDVI patterns were related to changes in the structure of canopies and not in pigment content, stand level PRI patterns suggested changes both in terms of canopy and of pigment content in leaves. Both SIF760/a and ΦPSII decreased progressively along senescence in both species. A strong increment in NPQ was evident in A. sativa while in S. italica NPQ values were lower. Our most important finding was that two chlorophyll fluorescence signals, ΦPSII and SIF760/a, correlated with the canopy PRI values in the two grasses assessed, even when tissues at different ontogenic stages were present. Even though significant changes occurred in the Total Chlr/Car ratio along senescence in both studied species, significant correlations between PRI and chlorophyll fluorescence signals might indicate the usefulness of this reflectance index as a proxy of photosynthetic RUE, at least under the conditions of this study. The relationships between stand level PRI and the fluorescence estimators (ΦPSII and SIF760/a) were positive in both cases. Therefore, an increase in PRI values as in the fluorescence parameters would indicate higher RUE. Copyright © 2016 Elsevier GmbH. All rights reserved.

  18. In Vivo Single-Cell Fluorescence and Size Scaling of Phytoplankton Chlorophyll Content.

    PubMed

    Álvarez, Eva; Nogueira, Enrique; López-Urrutia, Ángel

    2017-04-01

    In unicellular phytoplankton, the size scaling exponent of chlorophyll content per cell decreases with increasing light limitation. Empirical studies have explored this allometry by combining data from several species, using average values of pigment content and cell size for each species. The resulting allometry thus includes phylogenetic and size scaling effects. The possibility of measuring single-cell fluorescence with imaging-in-flow cytometry devices allows the study of the size scaling of chlorophyll content at both the inter- and intraspecific levels. In this work, the changing allometry of chlorophyll content was estimated for the first time for single phytoplankton populations by using data from a series of incubations with monocultures exposed to different light levels. Interspecifically, our experiments confirm previous modeling and experimental results of increasing size scaling exponents with increasing irradiance. A similar pattern was observed intraspecifically but with a larger variability in size scaling exponents. Our results show that size-based processes and geometrical approaches explain variations in chlorophyll content. We also show that the single-cell fluorescence measurements provided by imaging-in-flow devices can be applied to field samples to understand the changes in the size dependence of chlorophyll content in response to environmental variables affecting primary production.IMPORTANCE The chlorophyll concentrations in phytoplankton register physiological adjustments in cellular pigmentation arising mainly from changes in light conditions. The extent of these adjustments is constrained by the size of the phytoplankton cells, even within single populations. Hence, variations in community chlorophyll derived from photoacclimation are also dependent on the phytoplankton size distribution.

  19. Modeling chlorophyll a fluorescence transient: relation to photosynthesis.

    PubMed

    Stirbet, A; Riznichenko, G Yu; Rubin, A B; Govindjee

    2014-04-01

    To honor Academician Alexander Abramovitch Krasnovsky, we present here an educational review on the relation of chlorophyll a fluorescence transient to various processes in photosynthesis. The initial event in oxygenic photosynthesis is light absorption by chlorophylls (Chls), carotenoids, and, in some cases, phycobilins; these pigments form the antenna. Most of the energy is transferred to reaction centers where it is used for charge separation. The small part of energy that is not used in photochemistry is dissipated as heat or re-emitted as fluorescence. When a photosynthetic sample is transferred from dark to light, Chl a fluorescence (ChlF) intensity shows characteristic changes in time called fluorescence transient, the OJIPSMT transient, where O (the origin) is for the first measured minimum fluorescence level; J and I for intermediate inflections; P for peak; S for semi-steady state level; M for maximum; and T for terminal steady state level. This transient is a real signature of photosynthesis, since diverse events can be related to it, such as: changes in redox states of components of the linear electron transport flow, involvement of alternative electron routes, the build-up of a transmembrane pH gradient and membrane potential, activation of different nonphotochemical quenching processes, activation of the Calvin-Benson cycle, and other processes. In this review, we present our views on how different segments of the OJIPSMT transient are influenced by various photosynthetic processes, and discuss a number of studies involving mathematical modeling and simulation of the ChlF transient. A special emphasis is given to the slower PSMT phase, for which many studies have been recently published, but they are less known than on the faster OJIP phase.

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

    NASA Astrophysics Data System (ADS)

    Tucker, Compton

    2016-04-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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

  3. Chlorophyll fluorescence from creosote-exposed plants in mesocosms: Validation of a bioindicator

    SciTech Connect

    Marwood, C.A.; Harris, M.L.; Day, K.E.; Greenberg, B.M.; Solomon, K.R.

    1995-12-31

    The chlorophyll fluorescence assay is a rapid, sensitive measure of photosynthetic competence in higher plants and algae that can be used to detect the impact of toxicants at many sites in the plant cell. Chlorophyll fluorescence was examined in plants exposed to PAHs as part of a study to validate chlorophyll fluorescence as a bioindicator by correlating effects on fluorescence with population-level effects in outdoor mesocosms. The wood preservative creosote was used as a mixed PAH source. Two species of aquatic plants, Lemna gibba and Myriophyllum sp., were exposed to 0.1--100 uL/L of creosote in 12,000 L artificial ponds. Creosote was introduced into the mesocosms using different dosing schemes to simulate leaching and spill events. The pulse amplitude modulated fluorescence technique was used to measure several parameters from plants in situ during a 60-day exposure. Chlorophyll fluorescence parameters were compared to creosote effects on population-level growth. Chlorophyll fluorescence was inhibited by creosote at concentrations above 3 uL/L, which also caused a similar inhibition of plant growth in the mesocosms. However, chlorophyll fluorescence was more sensitive than growth endpoints at low creosote concentrations. The chlorophyll fluorescence assay also detected damage to the photosynthetic apparatus in plants after only a few days exposure to creosote. Thus, chlorophyll fluorescence from plants exposed to creosote was well correlated with environmentally relevant endpoints at the population level. The effects of the different dosing schemes on creosote toxicity will also be discussed.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  7. Chlorophyll Fluorescence in Leaves of Ficus tikoua Under Arsenic Stress.

    PubMed

    Wang, Yong; Chai, Liyuan; Yang, Zhihui; Mubarak, Hussani; Tang, Chongjian

    2016-10-01

    A greenhouse culture experiment was used to quantify effects of arsenic (As) stress on the growth and photochemical efficiency of Ficus tikoua (F. tikoua). Results showed growth of F. tikoua leaves was significantly inhibited at As concentrations higher than 80 μmol/L in solution. Root arsenic concentration was significantly higher than that in stem and leaf. The 320 and 480 μmol/L As concentrations in solution resulted in significant decreases in maximum quantum efficiency of photosystem II (PSII) (Fv/Fm), variable to initial chlorophyll fluorescence (Fv/Fo), and quantum yield of PSII electron transport (Y(II)) of F. tikoua leaves, whereas significantly higher non-photochemical quenching of fluorescence and photochemical quenching of fluorescence values were found at 160, 320 and 480 μmol/L As concentrations in solution, implying that PSII reaction centers were damaged at high As concentrations and that F. tikoua eliminates excess energy stress on the photochemical apparatus to adapt to As stress.

  8. Visualizing photosynthesis through processing of chlorophyll fluorescence images

    NASA Astrophysics Data System (ADS)

    Daley, Paul F.; Ball, J. Timothy; Berry, Joseph A.; Patzke, Juergen; Raschke, Klaus E.

    1990-05-01

    Measurements of terrestrial plant photosynthesis frequently exploit sensing of gas exchange from leaves enclosed in gas-tight, climate controlled chambers. These methods are typically slow, and do not resolve variation in photosynthesis below the whole leaf level. A photosynthesis visualization technique is presented that uses images of leaves employing light from chlorophyll (Chl) fluorescence. Images of Chl fluorescence from whole leaves undergoing steady-state photosynthesis, photosynthesis induction, or response to stress agents were digitized during light flashes that saturated photochemical reactions. Use of saturating flashes permitted deconvolution of photochemical energy use from biochemical quenching mechanisms (qN) that dissipate excess excitation energy, otherwise damaging to the light harvesting apparatus. Combination of the digital image frames of variable fluorescence with reference frames obtained from the same leaves when dark-adapted permitted derivation of frames in which grey scale represented the magnitude of qN. Simultaneous measurements with gas-exchange apparatus provided data for non-linear calibration filters for subsequent rendering of grey-scale "images" of photosynthesis. In several experiments significant non-homogeneity of photosynthetic activity was observed following treatment with growth hormones, or shifts in light or humidity, and following infection by virus. The technique provides a rapid, non-invasive probe for stress physiology and plant disease detection.

  9. Photosynthesis, chlorophyll fluorescence characteristics, and chlorophyll content of soybean seedlings under combined stress of bisphenol A and cadmium.

    PubMed

    Hu, Huiqing; Wang, Lihong; Wang, Qingqing; Jiao, Liya; Hua, Weiqi; Zhou, Qing; Huang, Xiaohua

    2014-11-01

    Bisphenol A (BPA) is ubiquitous in the environment because of its continual application in plastics and the epoxy resin industry. Cadmium (Cd) is a highly toxic heavy metal element mainly used in smelting, electroplating, and plastic and dye manufacturing. Pollution as a result of BPA and Cd exists simultaneously in many agricultural regions. However, little information is available regarding the combined effects of BPA and Cd on plants. The combined effects of BPA and Cd on the photosynthesis, chlorophyll fluorescence, and chlorophyll content of soybean seedlings were investigated using noninvasive technology. Combined treatment with 1.5 mg/L BPA and 0.2 mg/L Cd synergistically improved the net photosynthetic rate (Pn ), initial fluorescence (F0 ), maximal photochemical efficiency (Fv /Fm ), effective quantum yield of photosystem II (ΦPSII ), photosynthetic electron transport rate (ETR), and chlorophyll content. Combined treatment with 1.5 mg/L BPA and 3.0 mg/L Cd increased the F0 and decreased the Pn , Fv /Fm , ΦPSII , and ETR, whereas BPA and Cd exhibited an antagonistic effect. Furthermore, combined treatment with 17.2/50.0 mg/L BPA and 3.0/10.0 mg/L Cd synergistically decreased the Pn , Fv /Fm , ΦPSII , ETR, and chlorophyll content, although it increased the F0 . Finally, the effects of BPA and Cd on photosynthesis, chlorophyll fluorescence, and chlorophyll content ceased when BPA stress was stopped.

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

    NASA Technical Reports Server (NTRS)

    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. Contribution of Chlorophyll Fluorescence to the Reflectance of Corn Foliage

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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

  13. Continental shelf fish production estimation from CZCS chlorophyll data

    NASA Technical Reports Server (NTRS)

    Iverson, Richard L.

    1989-01-01

    A method for ocean fish production estimation was proposed for development. The method was to use data acquired with the Coastal Zone Color Scanner, and processed into chlorophyll concentrations by the GSFC ocean Sciences Division, in combination with fish production and primary production data acquired from different ocean areas. A linear relation exits between annual fish production and annual phytoplankton carbon production for a wide range of coastal ocean environments. The uses of several existing algorithms which relate primary production to CZCS chlorophyll data as input to the fish production regression model is proposed. A question relating phytoplankton production to CZCS chlorophyll was obtained by Eppley (1984) using chlorophyll data obtained from field samples, equivalent to chlorophyll data obtained from CZCS imagery, and primary production data obtained from ship-board observations on a wide variety of coastal and open ocean environments. This equation was modified with additional data and was successfully tested using CZCS data and field chlorophyll and phytoplankton production data obtained from northeastern North American continental shelf waters and Atlantic open ocean waters. The modified Eppley (1984) relation also estimated phytoplankton annual carbon production in the Sargasso Sea within the confidence limits of a mean value obtained from the Eppley (1984) equation for oceanic waters that provide about 90 percent of total ocean primary production. The modified Eppley production formula applied to CZCS chlorophyll data obtained from several northeastern North American coastal environments gave phytoplankton annual carbon production values similar to the values used in the fish production regression equation.

  14. Diurnal patterns of chlorophyll fluorescence and CO2 fixation in orchard grown Torreya taxifolia (Arn.).

    Treesearch

    Anita C. Koehn; Robert L. Doudrick

    1999-01-01

    Diurnal patterns of chlorophyll fluorescence and CO2 fixation in orchard measurements were taken on sunny days in October 1996, on three Torreya taxifolia (Arn.) plants grown in an open canopy orchard. Information from chlorophyll fluorescence quenching analysis indicated that during periods of highest light intensity and temperatures there were...

  15. Effects of Salinity on Chlorophyll Fluorescence of Nitrogen Fixing Soybean Plants (Glycine max L.)

    NASA Astrophysics Data System (ADS)

    Iliev, Ilko Ts.; Krezhova, Dora D.; Yanev, Tony K.; Kirova, Elisaveta B.

    2010-01-01

    Leaf chlorophyll ffluorescence was measured in order to assess the effect of salinity on nitrogen fixing soybean plants. Three day's seedlings were inoculated with suspension of Bradyrhizobium japonicum strain 273. The plants were grown at nutrient solution of Helrigel and salinyzed at stage of 2nd trifoliate expanded leaves by adding of NaCl at concentrations 40 mM and 80 mM. The chlorophyll fluorescence was registered by an USB2000 spectrometer in the spectral range 600-850 nm. As a source of actinic light a light emitting diode with the maximum of the light output at 470 nm was used. The course of the fluorescence spectra and the slow transient fluorescence kinetics were investigated. The Student's t-criterion and discriminant analysis were applied to estimate the changes between fluorescence spectra of control and treated soybean plants in five characteristic wavelengths in the spectral range 600-850 nm. Statistically significant differences were established by the t-criterion at p<0.05 for data at the first three wavelengths (at the middle of the leading edge, first maximum and at the middle of the first and second maximum) for both NaCl concentrations. The discriminant analysis confirmed these findings. A comparative analysis was performed with leaf spectral reflectance of the same plants collected in the spectral range 450-850 nm by the same spectrometer. All measurements were performed on the 14th day after the salinity treatment. The results from the implementation of the two remote sensing techniques (chlorophyll fluorescence and spectral reflectance) revealed that both NaCl concentrations brought to salinity stress in the nitrogen fixing soybean plants.

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

    PubMed

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

    2010-12-02

    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). Copyright © 2010 Elsevier B.V. All rights reserved.

  17. In vivo chlorophyll fluorescence study of hazardous waste site vegetation under field and controlled conditions

    SciTech Connect

    Mayasich, S.A.; Zygmont, N.J. CDM Federal Programs Corp., South Plainfield, NJ )

    1993-06-01

    Cattail (Typha sp.) and Arrow Arum (Peltandra virginica) were studied to determine the effects of cadmium and nickel contamination in a freshwater tidal marsh. An in vivo chlorophyll fluorescence instrument was used in the field to estimate photosynthetic capacity. No definitive effects on photosynthesis were observed. A laboratory study was then designed to determine whether fluorescence could detect sublethal impacts of cadmium and whether tolerant plants had developed in the contaminated area. Arrow Arum seeds collected from a reference wetland and from the contaminated wetland were grown in horticultural vermiculite with cadmium concentrations of 0, 1, 2, 5 and 10 mg/L. Results indicate that, regardless of seed origin, fluorescence can detect an effect at cadmium levels at which there are no visual signs of stress. However, the plants from the contaminated wetland exhibited reduced growth, and deformities in several individuals.

  18. A Graphical User Interface for Parameterizing Biochemical Models of Photosynthesis and Chlorophyll Fluorescence

    NASA Astrophysics Data System (ADS)

    Kornfeld, A.; Van der Tol, C.; Berry, J. A.

    2015-12-01

    Recent advances in optical remote sensing of photosynthesis offer great promise for estimating gross primary productivity (GPP) at leaf, canopy and even global scale. These methods -including solar-induced chlorophyll fluorescence (SIF) emission, fluorescence spectra, and hyperspectral features such as the red edge and the photochemical reflectance index (PRI) - can be used to greatly enhance the predictive power of global circulation models (GCMs) by providing better constraints on GPP. The way to use measured optical data to parameterize existing models such as SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes) is not trivial, however. We have therefore extended a biochemical model to include fluorescence and other parameters in a coupled treatment. To help parameterize the model, we then use nonlinear curve-fitting routines to determine the parameter set that enables model results to best fit leaf-level gas exchange and optical data measurements. To make the tool more accessible to all practitioners, we have further designed a graphical user interface (GUI) based front-end to allow researchers to analyze data with a minimum of effort while, at the same time, allowing them to change parameters interactively to visualize how variation in model parameters affect predicted outcomes such as photosynthetic rates, electron transport, and chlorophyll fluorescence. Here we discuss the tool and its effectiveness, using recently-gathered leaf-level data.

  19. Role of formation of statistical aggregates in chlorophyll fluorescence concentration quenching.

    PubMed

    Shi, Wu-Jun; Barber, James; Zhao, Yang

    2013-04-18

    Using extensive Monte Carlo simulations, a comprehensive investigation has been carried out on the phenomenon of chlorophyll fluorescence concentration quenching. Our results reveal that statistical aggregations of chlorophylls act mainly as trapping sites for excitation energy and lead to fluorescence quenching. Due to transition dipolar-dipolar interactions between the chlorophylls within a statistical aggregate, the associated oscillator strength changes in comparison to a monomer, and excited energy states show splitting. Further, as the lower energy states are more likely associated with lower oscillator strengths, the fluorescence intensity is observed to decrease. Due to the rapid energy transfer between chlorophyll molecules after photoexcitation, the excitonic energy can easily reach a statistical aggregate, where trapping of the exciton and its subsequent decay occur. With an increase in the chlorophyll concentration, the probability of statistical aggregation increases, thereby accentuating the fluorescence quenching effect.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed Central

    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 Fv/Fm and wood density and the quantity of wood decay in summer, but not in spring or autumn. Leaf chlorophyll fluorescence at 0.05 ms (the O step) could predict the quantity of wood decay in trees in spring. Bark chlorophyll fluorescence could predict wood density in spring using the Fv/Fm parameter, but not in summer or autumn. There was a consistent statistical relationship in spring, summer and autumn between the bark chlorophyll fluorescence parameter Fv/Fm and wood decay. This study indicates a relationship between chlorophyll fluorescence and wood structural changes, particularly with bark chlorenchyma. PMID:24790120

  3. Optical properties of intact leaves for estimating chlorophyll concentration

    NASA Technical Reports Server (NTRS)

    Carter, Gregory A.; Spiering, Bruce A.

    2002-01-01

    Changes in leaf chlorophyll content can serve as relative indicators of plant vigor and environmental quality. This study identified reflectance, transmittance, and absorptance wavebands and band ratios within the 400- to 850-nm range for intact leaves that could be used to estimate extracted leaf chlorophyll per unit leaf area (areal concentration) with minimal error. Leaf optical properties along with chlorophyll a, b, and a + b concentrations were measured for the planar-leaved sweetgum (Liquidambar styraciflua L.), red maple (Acer rubrum L.), wild grape (Vitis rotundifolia Michx.), and switchcane [Arundinaria gigantea (Walter) Muhl.], and for needles of longleaf pine (Pinus palustris Miller). Generally, reflectance, transmittance, and absorptance corresponded most precisely with chlorophyll concentrations at wavelengths near 700 nm, although regressions were also strong in the 550- to 625-nm range. A power function was superior to a simple linear function in yielding low standard deviations of the estimate (s). When data were combined among the planar-leaved species, s values were low at approximately 50 mumol/m2 out of a 940 mumol/m2 range in chlorophyll a + b at best-fit wavelengths of 707 to 709 nm. Minimal s values for chlorophyll a + b ranged from 32 to 62 mumol/m2 across species when band ratios having numerator wavelengths of 693 to 720 nm were used with the application of a power function. Optimal denominator wavelengths for the band ratios were 850 nm for reflectance and transmittance and 400 nm for absorptance. This information can be applied in designing field portable chlorophyll meters and in the landscape-scale remote sensing of plant responses to the environment.

  4. Optical properties of intact leaves for estimating chlorophyll concentration.

    PubMed

    Carter, Gregory A; Spiering, Bruce A

    2002-01-01

    Changes in leaf chlorophyll content can serve as relative indicators of plant vigor and environmental quality. This study identified reflectance, transmittance, and absorptance wavebands and band ratios within the 400- to 850-nm range for intact leaves that could be used to estimate extracted leaf chlorophyll per unit leaf area (areal concentration) with minimal error. Leaf optical properties along with chlorophyll a, b, and a + b concentrations were measured for the planar-leaved sweetgum (Liquidambar styraciflua L.), red maple (Acer rubrum L.), wild grape (Vitis rotundifolia Michx.), and switchcane [Arundinaria gigantea (Walter) Muhl.], and for needles of longleaf pine (Pinus palustris Miller). Generally, reflectance, transmittance, and absorptance corresponded most precisely with chlorophyll concentrations at wavelengths near 700 nm, although regressions were also strong in the 550- to 625-nm range. A power function was superior to a simple linear function in yielding low standard deviations of the estimate (s). When data were combined among the planar-leaved species, s values were low at approximately 50 mumol/m2 out of a 940 mumol/m2 range in chlorophyll a + b at best-fit wavelengths of 707 to 709 nm. Minimal s values for chlorophyll a + b ranged from 32 to 62 mumol/m2 across species when band ratios having numerator wavelengths of 693 to 720 nm were used with the application of a power function. Optimal denominator wavelengths for the band ratios were 850 nm for reflectance and transmittance and 400 nm for absorptance. This information can be applied in designing field portable chlorophyll meters and in the landscape-scale remote sensing of plant responses to the environment.

  5. Optical properties of intact leaves for estimating chlorophyll concentration

    NASA Technical Reports Server (NTRS)

    Carter, Gregory A.; Spiering, Bruce A.

    2002-01-01

    Changes in leaf chlorophyll content can serve as relative indicators of plant vigor and environmental quality. This study identified reflectance, transmittance, and absorptance wavebands and band ratios within the 400- to 850-nm range for intact leaves that could be used to estimate extracted leaf chlorophyll per unit leaf area (areal concentration) with minimal error. Leaf optical properties along with chlorophyll a, b, and a + b concentrations were measured for the planar-leaved sweetgum (Liquidambar styraciflua L.), red maple (Acer rubrum L.), wild grape (Vitis rotundifolia Michx.), and switchcane [Arundinaria gigantea (Walter) Muhl.], and for needles of longleaf pine (Pinus palustris Miller). Generally, reflectance, transmittance, and absorptance corresponded most precisely with chlorophyll concentrations at wavelengths near 700 nm, although regressions were also strong in the 550- to 625-nm range. A power function was superior to a simple linear function in yielding low standard deviations of the estimate (s). When data were combined among the planar-leaved species, s values were low at approximately 50 mumol/m2 out of a 940 mumol/m2 range in chlorophyll a + b at best-fit wavelengths of 707 to 709 nm. Minimal s values for chlorophyll a + b ranged from 32 to 62 mumol/m2 across species when band ratios having numerator wavelengths of 693 to 720 nm were used with the application of a power function. Optimal denominator wavelengths for the band ratios were 850 nm for reflectance and transmittance and 400 nm for absorptance. This information can be applied in designing field portable chlorophyll meters and in the landscape-scale remote sensing of plant responses to the environment.

  6. Time-resolved principal component imaging analysis of chlorophyll fluorescence induction for monitoring leaf water stress.

    PubMed

    Kobori, Hikaru; Tsuchikawa, Satoru

    2013-06-01

    Chlorophyll fluorescence induction is widely applied to investigate plant growth conditions by calculating the ratio of its intensity at oxidized and reduced states. We examined the applicability of a time-resolved profile of chlorophyll fluorescence induction with the aid of multivariate analysis to monitor the leaf water stress. Principal component (PC) analysis of time-resolved images of chlorophyll fluorescence induction and their score images were reconstructed. Control leaves (non-stressed leaves) and water-stressed leaves could be classified by normalized PC3 score images. This technique has the potential to monitor the water stress condition of plants by using a simple device.

  7. Chlorophyll content and chlorophyll fluorescence in tomato leaves infested with an invasive mealybug, Phenacoccus solenopsis (Hemiptera: Pseudococcidae).

    PubMed

    Huang, Jun; Zhang, Peng-Jun; Zhang, Juan; Lu, Yao-Bin; Huang, Fang; Li, Ming-Jiang

    2013-10-01

    Herbivore injury has indirect effects on the growth and performance of host plants through photosynthetic suppression. It causes uncertain reduction in photosynthesis, which likely depends on the degree of infestation. Rapid light curves provide detailed information on the saturation characteristics of electron transport as well as the overall photosynthetic performance of a plant. We examined the effects of different intensities of infestation of the invasive mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae), on the relative chlorophyll content and rapid light curves of tomato Solanum lycopersicum L. leaves using a chlorophyll meter and chlorophyll fluorescence measurement system, respectively, under greenhouse conditions. After 38 d of P. solenopsis feeding, relative chlorophyll content of tomato plants with initial high of P. solenopsis was reduced by 57.3%. Light utilization efficiency (α) for the initial high-density treatment was reduced by 42.4%. However, no significant difference between initial low-density treatment and uninfested control was found. The values of the maximum electron transport rate and minimum saturating irradiance for initial high-density treatment were reduced by 82.0 and 69.7%, respectively, whereas the corresponding values for low-density treatment were reduced by 55.9 and 58.1%, respectively. These data indicated that changes were induced by P. solenopsis feeding in the relative chlorophyll content and chlorophyll fluorescence of infested tomato plants. The results indicating that low initial infestation by P. solenopsis caused no change in relative leaf chlorophyll content or light utilization efficiency could have been because the plants rapidly adapted to P. solenopsis feeding or because of compensatory photosynthesis.

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

    NASA Astrophysics Data System (ADS)

    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

  9. Tundra photosynthesis captured by satellite-observed solar-induced chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    Luus, K. A.; Commane, R.; Parazoo, N. C.; Benmergui, J.; Euskirchen, E. S.; Frankenberg, C.; Joiner, J.; Lindaas, J.; Miller, C. E.; Oechel, W. C.; Zona, D.; Wofsy, S.; Lin, J. C.

    2017-02-01

    Accurately quantifying the timing and magnitude of respiration and photosynthesis by high-latitude ecosystems is important for understanding how a warming climate influences global carbon cycling. Data-driven estimates of photosynthesis across Arctic regions often rely on satellite-derived enhanced vegetation index (EVI); we find that satellite observations of solar-induced chlorophyll fluorescence (SIF) provide a more direct proxy for photosynthesis. We model Alaskan tundra CO2 cycling (2012-2014) according to temperature and shortwave radiation and alternately input EVI or SIF to prescribe the annual seasonal cycle of photosynthesis. We find that EVI-based seasonality indicates spring "green-up" to occur 9 days prior to SIF-based estimates, and that SIF-based estimates agree with aircraft and tower measurements of CO2. Adopting SIF, instead of EVI, for modeling the seasonal cycle of tundra photosynthesis can result in more accurate estimates of growing season duration and net carbon uptake by arctic vegetation.

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

    PubMed

    Fan, Lina; Wu, Qiang; Chu, Maoquan

    2012-01-01

    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. 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. 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.

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

    PubMed Central

    Fan, Lina; Wu, Qiang; Chu, Maoquan

    2012-01-01

    Background 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. PMID:22787402

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  13. Chlorophyll Breakdown in Senescent Banana Leaves: Catabolism Reprogrammed for Biosynthesis of Persistent Blue Fluorescent Tetrapyrroles

    PubMed Central

    Vergeiner, Clemens; Banala, Srinivas; Kräutler, Bernhard

    2013-01-01

    Chlorophyll breakdown is a visual phenomenon of leaf senescence and fruit ripening. It leads to the formation of colorless chlorophyll catabolites, a group of (chlorophyll-derived bilin-type) linear tetrapyrroles. Here, analysis and structure elucidation of the chlorophyll breakdown products in leaves of banana (Musa acuminata) is reported. In senescent leaves of this monocot all chlorophyll catabolites identified were hypermodified fluorescent chlorophyll catabolites (hmFCCs). Surprisingly, nonfluorescent chlorophyll catabolites (NCCs) were not found, the often abundant and apparently typical final chlorophyll breakdown products in senescent leaves. As a rule, FCCs exist only fleetingly, and they isomerize rapidly to NCCs in the senescent plant cell. Amazingly, in the leaves of banana plants, persistent hmFCCs were identified that accounted for about 80 % of the chlorophyll broken down, and yellow leaves of M. acuminata display a strong blue luminescence. The structures of eight hmFCCs from banana leaves were analyzed by spectroscopic means. The massive accumulation of the hmFCCs in banana leaves, and their functional group characteristics, indicate a chlorophyll breakdown path, the downstream transformations of which are entirely reprogrammed towards the generation of persistent and blue fluorescent FCCs. As expressed earlier in related studies, the present findings call for attention, as to still elusive biological roles of these linear tetrapyrroles. PMID:23946204

  14. Chlorophyll fluorescence: What is it and what do the numbers mean?

    Treesearch

    Gary A. Ritchie

    2006-01-01

    Although results of chlorophyll fluorescence (CF) measurements in nursery seedlings are becoming widely reported in the literature, the theory, terminology, and interpretation of these data are often obscure and confusing to nursery practitioners. This report outlines the underlying physiological basis for chlorophyll fluorometry and discusses measurement protocols and...

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

    PubMed

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

    2016-12-14

    Accurate estimation of terrestrial gross primary productivity (GPP) remains a challenge despite its importance in the global carbon cycle. Chlorophyll fluorescence (ChlF) has been recently adopted to understand photosynthesis and its response to the environment, particularly with remote sensing data. However, it remains unclear how ChlF and photosynthesis are linked at different spatial scales across the growing season. We examined seasonal relationships between ChlF and photosynthesis at the leaf, canopy, and ecosystem scales and explored how leaf-level ChlF was linked with canopy-scale solar-induced chlorophyll fluorescence (SIF) in a temperate deciduous forest at Harvard Forest, Massachusetts, USA. Our results show that ChlF captured the seasonal variations of photosynthesis with significant linear relationships between ChlF and photosynthesis across the growing season over different spatial scales (R(2 ) = 0.73, 0.77, and 0.86 at leaf, canopy, and satellite scales, respectively; P < 0.0001). We developed a model to estimate GPP from the tower-based measurement of SIF and leaf-level ChlF parameters. The estimation of GPP from this model agreed well with flux tower observations of GPP (R(2 ) = 0.68; P < 0.0001), demonstrating the potential of SIF for modeling GPP. At the leaf scale, we found that leaf Fq '/Fm ', the fraction of absorbed photons that are used for photochemistry for a light-adapted measurement from a pulse amplitude modulation fluorometer, was the best leaf fluorescence parameter to correlate with canopy SIF yield (SIF/APAR, R(2 ) = 0.79; P < 0.0001). We also found that canopy SIF and SIF-derived GPP (GPPSIF ) were strongly correlated to leaf-level biochemistry and canopy structure, including chlorophyll content (R(2 ) = 0.65 for canopy GPPSIF and chlorophyll content; P < 0.0001), leaf area index (LAI) (R(2 ) = 0.35 for canopy GPPSIF and LAI; P < 0.0001), and normalized difference vegetation index (NDVI) (R(2 ) = 0.36 for

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

    NASA Astrophysics Data System (ADS)

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

    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.

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

    NASA Technical Reports Server (NTRS)

    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

  18. Field experiments of multi-channel oceanographic fluorescence lidar for oil spill and chlorophyll- a detection

    NASA Astrophysics Data System (ADS)

    Li, Xiaolong; Zhao, Chaofang; Ma, Youjun; Liu, Zhishen

    2014-08-01

    A Multi-channel Oceanographic Fluorescence Lidar (MOFL), with a UV excitation at 355 nm and multiple receiving channels at typical wavelengths of fluorescence from oil spills and chlorophyll- a (Chl- a), has been developed using the Laser-induced Fluorescence (LIF) technique. The sketch of the MOFL system equipped with a compact multi-channel photomultiplier tube (MPMT) is introduced in the paper. The methods of differentiating the oil fluorescence from the background water fluorescence and evaluating the Chl- a concentration are described. Two field experiments were carried out to investigate the field performance of the system, i.e., an experiment in coastal areas for oil pollution detection and an experiment over the Yellow Sea for Chl- a monitoring. In the coastal experiment, several oil samples and other fluorescence substances were used to analyze the fluorescence spectral characteristics for oil identification, and to estimate the thickness of oil films at the water surface. The experiment shows that both the spectral shape of fluorescence induced from surface water and the intensity ratio of two channels ( I 495/ I 405) are essential to determine oil-spill occurrence. In the airborne experiment, MOFL was applied to measure relative Chl- a concentrations in the upper layer of the ocean. A comparison of relative Chl- a concentration measurements by MOFL and the Moderate Resolution Imaging Spectroradiometer (MODIS) indicates that the two datasets are in good agreement. The results show that the MOFL system is capable of monitoring oil spills and Chl- a in the upper layer of ocean water.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  20. [Photosynthetic Parameters Inversion Algorithm Study Based on Chlorophyll Fluorescence Induction Kinetics Curve].

    PubMed

    Qiu, Xiao-han; Zhang, Yu-jun; Yin, Gao-fang; Shi, Chao-yi; Yu, Xiao-ya; Zhao, Nan-jing; Liu, Wen-qing

    2015-08-01

    The fast chlorophyll fluorescence induction curve contains rich information of photosynthesis. It can reflect various information of vegetation, such as, the survival status, the pathological condition and the physiology trends under the stress state. Through the acquisition of algae fluorescence and induced optical signal, the fast phase of chlorophyll fluorescence kinetics curve was fitted. Based on least square fitting method, we introduced adaptive minimum error approaching method for fast multivariate nonlinear regression fitting toward chlorophyll fluorescence kinetics curve. We realized Fo (fixedfluorescent), Fm (maximum fluorescence yield), σPSII (PSII functional absorption cross section) details parameters inversion and the photosynthetic parameters inversion of Chlorella pyrenoidosa. And we also studied physiological variation of Chlorella pyrenoidosa under the stress of Cu(2+).

  1. A rapid, non-invasive procedure for quantitative assessment of drought survival using chlorophyll fluorescence

    PubMed Central

    Woo, Nick S; Badger, Murray R; Pogson, Barry J

    2008-01-01

    Background Analysis of survival is commonly used as a means of comparing the performance of plant lines under drought. However, the assessment of plant water status during such studies typically involves detachment to estimate water shock, imprecise methods of estimation or invasive measurements such as osmotic adjustment that influence or annul further evaluation of a specimen's response to drought. Results This article presents a procedure for rapid, inexpensive and non-invasive assessment of the survival of soil-grown plants during drought treatment. The changes in major photosynthetic parameters during increasing water deficit were monitored via chlorophyll fluorescence imaging and the selection of the maximum efficiency of photosystem II (Fv/Fm) parameter as the most straightforward and practical means of monitoring survival is described. The veracity of this technique is validated through application to a variety of Arabidopsis thaliana ecotypes and mutant lines with altered tolerance to drought or reduced photosynthetic efficiencies. Conclusion The method presented here allows the acquisition of quantitative numerical estimates of Arabidopsis drought survival times that are amenable to statistical analysis. Furthermore, the required measurements can be obtained quickly and non-invasively using inexpensive equipment and with minimal expertise in chlorophyll fluorometry. This technique enables the rapid assessment and comparison of the relative viability of germplasm during drought, and may complement detailed physiological and water relations studies. PMID:19014425

  2. Chlorophyll fluorescence lifetime imaging provides new insight into the chlorosis induced by plant virus infection.

    PubMed

    Lei, Rong; Jiang, Hongshan; Hu, Fan; Yan, Jin; Zhu, Shuifang

    2017-02-01

    Leaf chlorosis induced by plant virus infection has a short fluorescence lifetime, which reflects damaged photosynthetic complexes and degraded chloroplasts. Plant viruses often induce chlorosis and necrosis, which are intimately related to photosynthetic functions. Chlorophyll fluorescence lifetime measurement is a valuable noninvasive tool for analyzing photosynthetic processes and is a sensitive indicator of the environment surrounding the fluorescent molecules. In this study, our central goal was to explore the effect of viral infection on photosynthesis by employing chlorophyll fluorescence lifetime imaging (FLIM), steady-state fluorescence, non-photochemical quenching (NPQ), transmission electron microscopy (TEM), and pigment analysis. The data indicated that the chlorophyll fluorescence lifetime of chlorotic leaves was significantly shorter than that of healthy control leaves, and the fitted short lifetime component of chlorophyll fluorescence of chlorotic leaves was dominant. This dominant short lifetime component may result from damage to the structure of thylakoid, which was confirmed by TEM. The NPQ value of chlorotic leaves was slightly higher than that of healthy green leaves, which can be explained by increased neoxanthin, lutein and violaxanthin content relative to chlorophyll a. The difference in NPQ is slight, but FLIM can provide simple and direct characterization of PSII structure and photosynthetic function. Therefore, this technique shows great potential as a simple and rapid method for studying mechanisms of plant virus infection.

  3. Monitoring dynamical vegetation processes with solar-induced chlorophyll fluorescence measurements from space (Invited)

    NASA Astrophysics Data System (ADS)

    Moreno, J. F.; Guanter, L.; Alonso, L.; Gomez-Chova, L.; Drusch, M.; Kraft, S.; Carnicero, B.; Bezy, J.

    2009-12-01

    Fluorescence is a powerful non-invasive tool to track the status, resilience, and recovery of photochemical processes and moreover provides important information on overall vegetation photosynthetic performance with implications for related carbon sequestration, allowing to measure planetary photosynthesis by means of a global monitoring of steady-state chlorophyll fluorescence in terrestrial vegetation. The FLuorescence EXperiment (FLEX) is designed to observe the photosynthetic activity of the vegetation layer, by using a completely novel technique measuring the chlorophyll fluorescence signal that originates from the core of the photosynthetic machinery, i.e. the ‘breathing’ of the vegetation layer of the living planet. Conceived as a technology demonstration mission, it proposes a set of instruments for the measurement of the interrelated features of fluorescence, spectral reflectance, and canopy temperature, by using a dedicated small satellite flying in tandem with GMES Sentinel-3. This will provide a completely new possibility to quantify the photosynthetic efficiency of terrestrial ecosystems at the global scale, to improve the predictability of dynamical vegetation models on scales comprising canopies and biomes, and to provide an improved estimate of GPP for a better understanding of the global carbon cycle. It will also improve understanding of the role of vegetation in the coupled global carbon / water cycles, the global assessment of the vegetation health conditions and vegetation stress and the support the development of future crop production strategies in a changing climate. The measurement represent a challenge: the weak fluorescence signal is masked by the reflected background radiance, and accurate compensation of all perturbing effects becomes essential. Recent developments have demonstrated the feasibility of the measurements of canopy fluorescence from space. Recent model developments and data processing tools have made possible to

  4. Chlorophyll Fluorescence Near the Shoreline: Connections to Waves and Wave-Driven Currents

    NASA Astrophysics Data System (ADS)

    Omand, M. M.; Leichter, J. J.; Feddersen, F.; Franks, P. J.; McKenna, M. F.; Rippy, M.; Guza, R.

    2006-12-01

    Coastal phytoplankton communities may be significantly affected by breaking internal and surface gravity waves. For example, internal surges have been implicated in cross-shore transport, and rip currents (generated in the surf zone by breaking surface waves) are associated with mixing of water and organisms between the surf zone and the inner shelf. A month-long study at Huntington Beach CA in Fall 2006 will explore the connections between breaking wave driven currents and nutrients, chlorophyll-a fluorescence, phytoplankton taxa and abundance in the nearshore water. Two cross-shore mooring transects (deployed by USGS and Orange County Sanitation District) will sample the vertical structure of currents, temperature and salinity between 8 and 50 m water depth. Surface gravity waves will be measured with a directional wave buoy in 22 m depth. We will acquire additional small boat CTD+F, optical nitrate, Wire-Walker CTD+F, and bottle estimates of macronutrients, phytoplankton taxa and biomass. Different observing techniques are required in the surfzone. Currents, temperature, and waves will be measured on 7 durable, bottom-mounted tripods deployed between the shoreline and 4m depth. In situ chlorophyll-a fluorescence will be observed at 4 cross-shore locations. A novel jetski platform will provide high spatial resolution maps of chlorophyll and temperature, 20 cm below the water surface. Strong stratification is expected during the experiment, and results relevant to the propagation of internal waves and effects for phytoplankton and nutrients fluxes in the surfzone will be presented. Funded by CA Seagrant, CA Coastal Conservancy, and ONR.

  5. Prospects for chlorophyll fluorescence and vegetation remote sensing from the Orbiting Carbon Observatory-2

    NASA Astrophysics Data System (ADS)

    Frankenberg, C.; O'Dell, C.; Berry, J. A.; Guanter, L.; Joiner, J.; Pollock, H.; Taylor, T.

    2013-12-01

    The Orbiting Carbon Observatory-2 is a NASA mission designed to measure atmospheric CO2 and is scheduled to launch in July 2014. It's 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 μm range. Recently, it was shown that solar-induced chlorophyll fluorescence, a proxy for gross primary production (GPP, carbon uptake through photosynthesis), could be accurately retrieved from space using high-resolution spectra in the 750 nm range. 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 0.3-0.5Wm-2sr-1μm-1, 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 errors for global carbon cycle research. Eventually, the combination of net ecosystem exchange (NEE) and proxy-estimates of GPP from the same satellite will provide a more process-based understanding of the global carbon cycle. Highlights from fluorescence results of the GOSAT satellite will be shown to emphasize the potential of OCO-2.

  6. Chlorophyll fluorescence response to water and nitrogen deficit

    NASA Astrophysics Data System (ADS)

    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

  7. Measuring solar induced chlorophyll fluorescence (SIF) in the Amazon rainforest

    NASA Astrophysics Data System (ADS)

    Kornfeld, A.; Stutz, J.; Berry, J. A.

    2016-12-01

    Measurement of solar induced chlorophyll fluorescence (SIF) has, in our hands, been fraught with missteps and puzzling problems. Here we describe lessons we have learned and the resulting novel system recently installed in the Amazon rainforest near Manaus, Brazil. The system is designed to measure light from 740 - 780 nm, enabling us to compare SIF computed from Fraunhofer lines in an optically transparent band of the atmosphere (745 - 759 nm) with SIF computed using the telluric O2A band (760 - 770 nm). Fraunhofer line analysis requires high optical resolution (better than 0.2 nm) to detect the relatively narrow lines, but we discovered that fiber-optic diffraction-grating spectrometers are sensitive to very small inhomogeneities in the lighting. Errors resulting from this autocorrelated but random noise were similar in magnitude to the SIF signal itself. Optical diffusers reduce this problem, leading to our final design: a sealed cylinder, dubbed Rotaprism, in which a rotatable prism selects whether light from upward- or downward-looking windows enters an axially-placed optical fiber. Cosine-correcting opal glass covering the windows not only solves the noise issue but also makes the measurements correspond to photon flux. Rotaprism also maximizes the amount of light reaching the spectrometer - maximizing the signal:noise ratio - by avoiding the need for lossy optical switches and fiber splitters. Rotaprism is driven by a pneumatic actuator that is controlled by electronic valves attached to a pressurized N2 source. The gas exhausts into the temperature-controlled spectrometer enclosure to help purge the optics. Finally, custom software provides fault-tolerant control and data acquisition, ensuring that measurements continue with little or no intervention at the remote field site despite unreliable power. Analysis of initial data demonstrates the advantage of Fraunhofer line SIF analysis: due to the atmosphere transparency in this band, the results are more

  8. Water stress response of conventional and transgenic soybean plants monitored by chlorophyll a fluorescence.

    PubMed

    Caires, A R L; Scherer, M D; Santos, T S B; Pontim, B C A; Gavassoni, W L; Oliveira, S L

    2010-05-01

    Two soybean cultivars, one conventional and a glyphosate-tolerant (transgenic), were submitted to the water stress and the chlorophyll a fluorescence induced by UV light was monitored daily during 16 days. In this work, 40 pots in total, 20 per cultivar were used in the investigation. Each cultivar was divided in two groups, the control group and the group submitted to the water stress. The stress response of the cultivars was monitored by red to far-red fluorescence ratio. The data indicate that the water stress induced the earliest changes on the fluorescence ratio and chlorophyll content for the conventional cultivar. In addition, a comparative analysis of the fluorescence ratios of the cultivars reveals that conventional plants have higher chlorophyll content than transgenic ones. This result might be useful in the development of methodologies able to distinguish conventional to transgenic apart.

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

    NASA Technical Reports Server (NTRS)

    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

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

    NASA Technical Reports Server (NTRS)

    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

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

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

    PubMed Central

    Mishra, Anamika; 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 established electrolyte leakage method on detached leaves. We found that, during progressive cooling, the minimal chlorophyll fluorescence emission rose strongly and that this rise was highly dependent on the cold tolerance of the accessions. Maximum quantum yield of PSII photochemistry and steady state fluorescence normalized to minimal fluorescence were also highly correlated to the cold tolerance measured by the electrolyte leakage method. In order to further increase the capacity of the fluorescence detection to reveal the low temperature tolerance, we applied combinatorial imaging that employs plant classification based on multiple fluorescence features. We found that this method, by including the resolving power of several fluorescence features, can be well employed to detect cold tolerance already at mild sub-zero temperatures. Therefore, there is no need to freeze the screened plants to the largely damaging temperatures of around −15°C. This, together with the method's easy applicability, represents a major advantage of the fluorescence technique over the conventional electrolyte leakage method. PMID:21427532

  13. Chlorophyll breakdown in senescent banana leaves: catabolism reprogrammed for biosynthesis of persistent blue fluorescent tetrapyrroles.

    PubMed

    Vergeiner, Clemens; Banala, Srinivas; Kräutler, Bernhard

    2013-09-09

    Chlorophyll breakdown is a visual phenomenon of leaf senescence and fruit ripening. It leads to the formation of colorless chlorophyll catabolites, a group of (chlorophyll-derived bilin-type) linear tetrapyrroles. Here, analysis and structure elucidation of the chlorophyll breakdown products in leaves of banana (Musa acuminata) is reported. In senescent leaves of this monocot all chlorophyll catabolites identified were hypermodified fluorescent chlorophyll catabolites (hmFCCs). Surprisingly, nonfluorescent chlorophyll catabolites (NCCs) were not found, the often abundant and apparently typical final chlorophyll breakdown products in senescent leaves. As a rule, FCCs exist only fleetingly, and they isomerize rapidly to NCCs in the senescent plant cell. Amazingly, in the leaves of banana plants, persistent hmFCCs were identified that accounted for about 80 % of the chlorophyll broken down, and yellow leaves of M. acuminata display a strong blue luminescence. The structures of eight hmFCCs from banana leaves were analyzed by spectroscopic means. The massive accumulation of the hmFCCs in banana leaves, and their functional group characteristics, indicate a chlorophyll breakdown path, the downstream transformations of which are entirely reprogrammed towards the generation of persistent and blue fluorescent FCCs. As expressed earlier in related studies, the present findings call for attention, as to still elusive biological roles of these linear tetrapyrroles. © 2013 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

  14. [Changes of photosynthesis parameters and chlorophyll fluorescence around sprout tumble of Pinellia ternata under high temperature stress].

    PubMed

    Xue, Jianping; Wang, Xing; Zhang, Aimin; Chang, Li

    2010-09-01

    To study the change of photosynthesis and chlorophyll fluorescence characteristics of Pinellia ternata around sprout tumble. Tubers of P. ternata were cultured firstly at (25 +/- 1) degrees C for certain days, and then they were coerced under 37 degrees C stress in the same artificial climate boxes. The chlorophyll contents, photosynthesis and chlorophyll fluorescence during different stages of high temperature stress were measured. After under high temperature stress, the chlorophyll contents, the ratio of chlorophyll a/b, photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), maximum fluorescence (Fm), quantum yield of PS II (phi (PS II)), intrinsic photochemical efficiency of PS II (Fv/Fm) and the chlorophyll photochemical quenching (qP) decreased, but the intercellular CO2 concentration (Ci), minimal fluorescence (F0), the chlorophyll nonphotochemical quenching (NPQ) increased.

  15. Estimating global chlorophyll changes over the past century

    NASA Astrophysics Data System (ADS)

    Boyce, Daniel G.; Dowd, Michael; Lewis, Marlon R.; Worm, Boris

    2014-03-01

    Marine phytoplankton account for approximately half of the production of organic matter on earth, support virtually all marine ecosystems, constrain fisheries yields, and influence climate and weather. Despite this importance, long-term trajectories of phytoplankton abundance or biomass are difficult to estimate, and the extent of changes is unresolved. Here, we use a new, publicly-available database of historical shipboard oceanographic measurements to estimate long-term changes in chlorophyll concentration (Chl; a widely used proxy for phytoplankton biomass) from 1890 to 2010. This work builds upon an earlier analysis (Boyce et al., 2010) by taking published criticisms into account, and by using recalibrated data, and novel analysis methods. Rates of long-term chlorophyll change were estimated using generalized additive models within a multi-model inference framework, and post hoc sensitivity analyses were undertaken to test the robustness of results. Our analysis revealed statistically significant Chl declines over 62% of the global ocean surface area where data were present, and in 8 of 11 large ocean regions. While Chl increases have occurred in many locations, weighted syntheses of local- and regional-scale estimates confirmed that average chlorophyll concentrations have declined across the majority of the global ocean area over the past century. Sensitivity analyses indicate that these changes do not arise from any bias between data types, nor do they depend upon the method of spatial or temporal aggregation, nor the use of a particular statistical model. The wider consequences of this long-term decline of marine phytoplankton are presently unresolved, but will need to be considered in future studies of marine ecosystem structure, geochemical cycling, and fishery yields.

  16. Chlorophyll fluorescence induction, chlorophyll content, and chromaticity characteristics of leaves as indicators of photosynthetic apparatus senescence in arboreous plants.

    PubMed

    Ptushenko, V V; Ptushenko, O S; Tikhonov, A N

    2014-03-01

    Parameters of chlorophyll fluorescence induction (CFI) are widely used for assessment of the physiological state of higher plant leaves in biochemical, physiological, and ecological studies and in agricultural applications. In this work we have analyzed data on variability of some CFI parameters - ΦPSII(max) = Fv/Fm (relative value of variable fluorescence), qNPQ (non-photochemical quenching coefficient), RFd ("vitality index") - in autumnal leaves of ten arboreous plant species of the temperate climatic zone. The correlation between the chlorophyll content in the leaves and fluorescence parameters characterizing photosynthetic activity is shown for two representative species, the small-leaved linden Tilia cordata and the rowan tree Sorbus aucuparia. During the period of mass yellowing of the leaves, the ΦPSII(max) value can be used as an adequate characteristic of their photochemical activity, while in summer the qNPQ or RFd values are more informative. We have established a correlation between the ΦPSII(max) value, which characterizes the maximal photochemical activity of the photosystem II, and "chromaticity coordinates" of a leaf characterizing its color features. The chromaticity coordinates determined from the optical reflection spectra of the leaves serve as a quantitative measure of their hues, and this creates certain prerequisites for a visual expert assessment of the physiological state of the leaves.

  17. Modelling satellite-level solar-induced chlorophyll fluorescence and its comparison with OCO-2 observations

    NASA Astrophysics Data System (ADS)

    Pradhan, Rohit; Gohel, Ankit

    2016-04-01

    Solar Induced chlorophyll Fluorescence (SIF) is a direct measure of photosynthesis rate as it is emitted by the photosynthetic system. This paper reports a method to model SIF over India by assimilating spatial inputs (LAI, Chlorophyll content etc.) into FluorMOD leaf and canopy model. Modelled SIF was then compared to Orbiting Carbon Observatory (OCO-2) SIF observations from September 2014 to August 2015. Modelled SIF at 757 nm averaged over the country varied between 0.18 to 0.33 W m-2 sr-1 μm-1 whereas SIF at 771 nm varied between 0.10 to 0.19 W m-2 sr-1 μm-1. OCO-2 observed SIF at 757 nm averaged over the country ranged from 0.18 to 0.42 Wm-2sr-1μm-1. Fairly good agreement (r=0.77, p<0.01 at 757nm; r=0.71, p<0.05 at 771 nm) was observed between modelled and observed SIF except for summer months of April and May. This paper presents a new approach to upscale a leaf and canopy level model to estimate SIF over entire country.

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

    PubMed

    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.

  19. Lunisolar tidal force and its relationship to chlorophyll fluorescence in Arabidopsis thaliana

    PubMed Central

    Fisahn, Joachim; Klingelé, Emile; Barlow, Peter

    2015-01-01

    The yield of chlorophyll fluorescence Ft was measured in leaves of Arabidopsis thaliana over periods of several days under conditions of continuous illumination (LL) without the application of saturating light pulses. After linearization of the time series of the chlorophyll fluorescence yield (ΔFt), oscillations became apparent with periodicities in the circatidal range. Alignments of these linearized time series ΔFt with the lunisolar tidal acceleration revealed high degrees of synchrony and phase congruence. Similar congruence with the lunisolar tide was obtained with the linearized quantum yield of PSII (ΔФII), recorded after application of saturating light pulses. These findings strongly suggest that there is an exogenous timekeeper which is a stimulus for the oscillations detected in both the linearized yield of chlorophyll fluorescence (ΔFt) and the linearized quantum yield of PSII (ΔФII). PMID:26376108

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

    PubMed

    Chen, Chen; Gong, Nan; Li, Zuowei; Sun, Chenglin; Men, Zhiwei

    2017-09-21

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

  1. The Chlorophyll Fluorescence Imaging Spectrometer (CFIS): A New Airborne Instrument for Quantifying Solar-Induced Fluorescence

    NASA Astrophysics Data System (ADS)

    Drewry, D.; Frankenberg, C.; Verma, M.; Berry, J. A.; Schimel, D.; Geier, S.; Schwochert, M.

    2015-12-01

    Recent demonstrations of the retrieval of vegetation solar-induced fluorescence (SIF) emission from satellite platforms have opened up the possibility of remotely monitoring photosynthetic function, in addition to the structural and biochemical parameters that characterize the current capabilities of vegetation observing systems. These satellite retrievals, from platforms such as GOSAT, GOME-2, and most recently NASA's Orbiting Carbon Observatory 2 (OCO-2), provide powerful evidence of the correlation between vegetation productivity and SIF at seasonal to annual timescales, and at spatial resolutions of tens to hundreds of kilometers. The Chlorophyll Fluorescence Imaging Spectrometer (CFIS) was recently developed for OCO-2 validation purposes and provides an airborne capability to help fill the spatial gap between leaf- or canopy-level observations of SIF flux and extensive satellite footprints. The flexibility of an airborne instrument likewise allows for studies of the temporal variability of SIF emission over consecutive days, or with meteorological variability throughout a day. CFIS is a high resolution (<0.1nm) spectrometer covering the 740-770nm wavelength range, optimized for SIF quantification. Here we present an overview of the instrument design and capabilities, along with the retrieval methodology. An evaluation of data collected during initial campaigns conducted during the spring and summer of 2015 are also presented, demonstrating variability within and between days for campaigns spanning multiple days in the Midwest US and Northern California. Results will be compared to OCO-2 data as well as flux-tower measurements made during the CFIS flights.

  2. Phenology and gross primary production of maize croplands from chlorophyll light absorption, solar-induced chlorophyll fluorescence and CO2 flux tower approaches

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    It is important to accurately quantify cropland gross primary productivity (GPP) for monitoring cropland status and the carbon budgets. Both sattellite-based light-use efficiency (LUE) models and process-based terrestrial biosphere models (TBM) have been widely used to quantify cropland GPP at different scales. Space-borne solar-induced chlorophyll fluorescence (SIF) has recently shown the ability to monitor photosynthesis from space. In this presentation, we compared the three approaches for estimating seasonal dynamics and magnitudes of maize cropland GPP during 2007-2011 at a cropland site in Nebraska, USA. Three approaches used were a satellite-based Vegetation Photosynthsis Model (VPM) with the concept of light absorption by chlorophyll, the process-based Soil-Canopy Observation of Photosynthesis and Energy (SCOPE), and space-borne SIF. Validations against flux tower estimates demonstrate that maize GPP can be accurately estimated with the three models. The SCOPE model provides the best simulation of maize GPP by incorporation of satellite SIF measurements. On the other hand, satellite-based VPM model shows the potential for scaling-up GPP estimation of intensified managed croplands with higher spatial resolution data from MODIS. The results show that the space-borne SIF data can be simply and directly used not only to monitor actual photosynthesis of crop without much ancillary information, but also to improve cropland GPP modeling by constraining process-based TBM.

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

    NASA Technical Reports Server (NTRS)

    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.

  4. Remote estimation of canopy chlorophyll content in crops

    NASA Astrophysics Data System (ADS)

    Gitelson, Anatoly A.; Viña, Andrés; Ciganda, Verónica; Rundquist, Donald C.; Arkebauer, Timothy J.

    2005-04-01

    Accurate estimation of spatially distributed chlorophyll content (Chl) in crops is of great importance for regional and global studies of carbon balance and responses to fertilizer (e.g., nitrogen) application. In this paper a recently developed conceptual model was applied for remotely estimating Chl in maize and soybean canopies. We tuned the spectral regions to be included in the model, according to the optical characteristics of the crops studied, and showed that the developed technique allowed accurate estimation of total Chl in both crops, explaining more than 92% of Chl variation. This new technique shows great potential for remotely tracking the physiological status of crops, with contrasting canopy architectures, and their responses to environmental changes.

  5. Chlorophyll Fluorescence as a Possible Tool for Salinity Tolerance Screening in Barley (Hordeum vulgare L.).

    PubMed Central

    Belkhodja, R.; Morales, F.; Abadia, A.; Gomez-Aparisi, J.; Abadia, J.

    1994-01-01

    The application of chlorophyll fluorescence measurements to screening barley (Hordeum vulgare L.) genotypes for salinity tolerance has been investigated. Excised barley leaves were cut under water and incubated with the cut end immersed in water or in a 100-mM NaCl solution, either in the dark or in high light. Changes in rapid fluorescence kinetics occurred in excised barley leaves exposed to the saline solution only when the incubation was carried out in the presence of high light. Fluorescence changes consisted of decreases in the variable to maximum fluorescence ratio and in increases in the relative proportion of variable fluorescence leading to point I in the Kautsky fluorescence induction curve. These relative increases in fluorescence at point I appeared to arise from a delayed plastoquinone reoxidation in the dark, since they disappeared after short, far-red illumination, which is known to excite photosystem I preferentially. We show that a significant correlation existed between some fluorescence parameters, measured after a combined salt and high-light treatment, and other independent measurements of salinity tolerance. These results suggest that chlorophyll fluorescence, and especially the relative fluorescence at point I in the Kautsky fluorescence induction curve, could be used for the screening of barley genotypes for salinity tolerance. PMID:12232117

  6. Modeling regional cropland GPP by empirically incorporating sun-induced chlorophyll fluorescence into a coupled photosynthesis-fluorescence model

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Guanter, L.; Van der Tol, C.; Joiner, J.; Berry, J. A.

    2015-12-01

    Global sun-induced chlorophyll fluorescence (SIF) retrievals are currently available from several satellites. SIF is intrinsically linked to photosynthesis, so the new data sets allow to link remotely-sensed vegetation parameters and the actual photosynthetic activity of plants. In this study, we used space measurements of SIF together with the Soil-Canopy Observation of Photosynthesis and Energy (SCOPE) balance model in order to simulate regional photosynthetic uptake of croplands in the US corn belt. SCOPE couples fluorescence and photosynthesis at leaf and canopy levels. To do this, we first retrieved a key parameter of photosynthesis model, the maximum rate of carboxylation (Vcmax), from field measurements of CO2 and water flux during 2007-2012 at some crop eddy covariance flux sites in the Midwestern US. Then we empirically calibrated Vcmax with apparent fluorescence yield which is SIF divided by PAR. SIF retrievals are from the European GOME-2 instrument onboard the MetOp-A platform. The resulting apparent fluorescence yield shows a stronger relationship with Vcmax during the growing season than widely-used vegetation index, EVI and NDVI. New seasonal and regional Vcmax maps were derived based on the calibration model for the cropland of the corn belt. The uncertainties of Vcmax were also estimated through Gaussian error propagation. With the newly derived Vcmax maps, we modeled regional cropland GPP during the growing season for the Midwestern USA, with meteorological data from MERRA reanalysis data and LAI from MODIS product (MCD15A2). The results show the improvement in the seasonal and spatial patterns of cropland productivity in comparisons with both flux tower and agricultural inventory data.

  7. Diurnal and directional responses of chlorophyll fluorescence and pri in a cornfield

    USDA-ARS?s Scientific Manuscript database

    Two high spectral resolution reflectance-based indices were used to assess whether vegetation in a cornfield was performing near-optimally or exhibiting symptoms of environmental stress. These were the Photochemical Reflectance Index (PRI) and solar-induced Chlorophyll Fluorescence (SIF). This study...

  8. Plant Chlorophyll fluorescence: active and passive measurements at canopy and leaf scales with different nitrogen treatments

    USDA-ARS?s Scientific Manuscript database

    Most studies assessing chlorophyll fluorescence (ChlF) have examined leaf responses to environmental stress conditions using active techniques. Alternatively, passive techniques are able to measure ChlF at both leaf and canopy scales. However, although the measurement principles of both techniques a...

  9. Water deficit and salt stress diagnosis through LED induced chlorophyll fluorescence analysis in Jatropha curcas L.

    PubMed

    Silva, E A; Gouveia-Neto, A S; Oliveira, R A; Moura, D S; Cunha, P C; Costa, E B; Câmara, T J R; Willadino, L G

    2012-03-01

    LED induced chlorophyll fluorescence analysis is employed to investigate the effect of water deficit and salt stress upon the growth process of Jatropha curcas L.. Red(Fr) and far-red(FFr) chlorophyll fluorescence around 685 nm and 735 nm, respectively, were observed and examined as a function of the stress intensity(salt concentration and water deficit). The fluorescence ratio Fr/FFr which is a valuable nondestructive and nonintrusive indicator of the chlorophyll content of leaves was exploited to monitor the jatropha plants under stress. The data indicated that salinity plays a minor role in the chlorophyll concentration of leaves for NaCl concentrations in the 25 to 200 mM range. The fluorescence ratio also permitted the detection of damage caused by water deficit in the early stages of the plants growing process. A significant variation of the Fr/FFr ratio was observed in the first 10 days of the experiment, and before signs of visual stress became apparent. The results suggest that the Fr/FFr ratio is an early-warning indicator of water deficit stress.

  10. Global and time-resolved monitoring of crop photosynthesis with chlorophyll fluorescence

    USDA-ARS?s Scientific Manuscript database

    Global monitoring of agricultural productivity is critical in a world under a continuous increase of food demand. Here we have used new spaceborne retrievals of chlorophyll fluorescence, an emission quantity intrinsically linked to photosynthesis, to derive spatially explicit photosynthetic uptake r...

  11. Interregional difference in spring neap variations in stratification and chlorophyll fluorescence during summer in a tidal sea (Yatsushiro Sea, Japan)

    NASA Astrophysics Data System (ADS)

    Aoki, Kazuhiro; Onitsuka, Goh; Shimizu, Manabu; Matsuo, Hitoshi; Kitadai, Yuuki; Ochiai, Hironori; Yamamoto, Takeshi; Furukawa, Shinpei

    2016-10-01

    Spring neap variations in stratification and chlorophyll fluorescence were studied during the summers of 2011-2014 in a tidal sea (Yatsushiro Sea, Japan) using monitoring data and hydrodynamic models. Vertical profiles of salinity, temperature and chlorophyll fluorescence were collected nearly weekly from nine stations in this sea during the same period. Composite analysis using vertical profiles of density clearly indicated enhancement of the stratification during the neap tide and a vertically mixed water column during the spring tide in the tidal area. Interregional differences were revealed in the variation of chlorophyll fluorescence with the spring neap tidal cycle. More notable increases in chlorophyll fluorescence were observed during the neap tide in the tidal area around the narrow strait than in the inner area. Temporal stratification led to an increase in the chlorophyll fluorescence in the tidal strait during the neap tide.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  14. [Vegetation index estimation by chlorophyll content of grassland based on spectral analysis].

    PubMed

    Xiao, Han; Chen, Xiu-Wan; Yang, Zhen-Yu; Li, Huai-Yu; Zhu, Han

    2014-11-01

    Comparing the methods of existing remote sensing research on the estimation of chlorophyll content, the present paper confirms that the vegetation index is one of the most practical and popular research methods. In recent years, the increasingly serious problem of grassland degradation. This paper, firstly, analyzes the measured reflectance spectral curve and its first derivative curve in the grasslands of Songpan, Sichuan and Gongger, Inner Mongolia, conducts correlation analysis between these two spectral curves and chlorophyll content, and finds out the regulation between REP (red edge position) and grassland chlorophyll content, that is, the higher the chlorophyll content is, the higher the REIP (red-edge inflection point) value would be. Then, this paper constructs GCI (grassland chlorophyll index) and selects the most suitable band for retrieval. Finally, this paper calculates the GCI by the use of satellite hyperspectral image, conducts the verification and accuracy analysis of the calculation results compared with chlorophyll content data collected from field of twice experiments. The result shows that for grassland chlorophyll content, GCI has stronger sensitivity than other indices of chlorophyll, and has higher estimation accuracy. GCI is the first proposed to estimate the grassland chlorophyll content, and has wide application potential for the remote sensing retrieval of grassland chlorophyll content. In addition, the grassland chlorophyll content estimation method based on remote sensing retrieval in this paper provides new research ideas for other vegetation biochemical parameters' estimation, vegetation growth status' evaluation and grassland ecological environment change's monitoring.

  15. Variability in chlorophyll fluorescence spectra of eggplant fruit grown under different light environments: a case study.

    PubMed

    Ospina Calvo, Brian; Parapugna, Tamara L; Lagorio, M Gabriela

    2017-03-13

    The main goal of the present work was to clarify physiological strategies in plants whose chloroplasts were developed under different light environments. The specific objective was to elucidate the influence of the spectral distribution of light on the chlorophyll fluorescence ratio and on photosynthetic parameters. To achieve this purpose, three species of eggplant fruit (black, purple and white striped and white) were used as a case study and their chlorophyll fluorescence was analyzed in detail. Spectra of the non-variable fluorescence in each part of the fruit were corrected for distortions by light reabsorption processes using a physical model. The main conclusion of this work was that the corrected fluorescence ratio was dependent on the contribution of each photosystem to the fluorescence and consequently on the environmental lighting conditions, becoming higher when illumination was rich in long wavelengths. Variable chlorophyll fluorescence, similar to that observed from plant leaves, was detected for the pulp of the black eggplant, for the pulp of the purple and white striped eggplant and for the intact fruit of the black eggplant. The maximum quantum efficiency of photosystem II in the light-adapted state (F'v/F'm), the quantum efficiency of photosystem II (ΦPSII), and the photochemical and non-photochemical quenching coefficients (qP and qNP/NPQ respectively) were determined in each case. The results could be explained very interestingly, in relation with the proportion of exciting light reaching each photosystem (I and II). The photochemical parameters obtained from variable chlorophyll fluorescence, allowed us to monitor non-destructively the physiological state of the black fruit during storage under both chilled or room-temperature conditions.

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

    PubMed

    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.

  17. Variability in particle attenuation and chlorophyll fluorescence in the tropical Pacific: Scales, patterns, and biogeochemical implications

    NASA Astrophysics Data System (ADS)

    Claustre, Hervé; Morel, André; Babin, Marcel; Cailliau, Caroline; Marie, Dominique; Marty, Jean-Claude; Tailliez, Dominique; Vaulot, Daniel

    1999-02-01

    The variability in particle attenuation (cp) and in chlorophyll in situ fluorescence (Fis) was examined in November 1994 along 150°W in the Pacific Ocean. Two main sources of variation in cp and Fis profiles are identified by analyzing data from a 16°S-1°N transect, and from two 5 day stations (5°S and 16°S). The first source reflects changes in the trophic status resulting from prevailing hydrodynamical regimes at large scales. By using flow cytometric data and some assumptions about the size distribution of the different biological stocks, a decomposition of cp into its vegetal (cveg) and nonvegetal (cnveg) components is attempted. Within the euphotic layer, cveg accounts for 43% of the total cp signal at the equator and for only 20% in the South Pacific gyre. The nonvegetal component is then subdivided into heterotrophic organisms and detritus contributions. The detrital material is an important contributor with 43% of cp at 5°S and 55% at 16°S. A further decomposition of Fis and cveg into the three dominant phytoplanktonic groups (Prochlorococcus, Synechococcus, and picoeucaryotes) confirms that picoeucaryotes are important contributors of the vegetal biomass, especially within and below the deep chlorophyll maximum (DCM) (>50% of the algal stock) at 16°S. The second, and essentially local, source of variation is related to specific rhythms in biological and physiological processes. The prominent signals detected during the time series occur at the daily scale: besides the pronounced fluorescence depression at noon in upper layers, particle attenuation in all the layers examined and fluorescence in the DCM display conspicuous daily oscillations. They result from the balance between daytime accumulation and night removal of particles, of algal cells in particular. Finally, the estimation of cp-based growth rates points out the surprisingly rapid turnover time of the whole particulate matter stock in oligotrophic waters (16°S), not only in the euphotic

  18. Metal accumulation and toxicity measured by PAM--chlorophyll fluorescence in seven species of marine macroalgae.

    PubMed

    Baumann, Hans A; Morrison, Liam; Stengel, Dagmar B

    2009-05-01

    The effects of five metals, copper (Cu), chromium (Cr), Zinc (Zn), cadmium (Cd) and lead (Pb), on photosynthetic activity, measured as pulse amplitude modulation (PAM) chlorophyll fluorescence yield, was monitored in seven species of green, red and brown macroalgae over a 14d period. The 10micromoll(-1) of Cr and Zn reduced chlorophyll fluorescence of all species by day 4, and 10micromoll(-1) of Cu and Cd reduced the fluorescence of some species; however, fluorescence yields of all species were unaffected by 10micromoll(-1) of Pb. Metals were generally accumulated in the order of Cu>Pb>Zn>Cr>Cd. Ulva intestinalis accumulated the highest amounts of all metals, and Cladophora rupestris the lowest. A relationship between internal metal concentration and fluorescence was not always evident as in some cases fluorescence was reduced at low metal contents. In the case of Zn, fluorescence was lowest in plants which contained lowest concentrations after 14d-exposure, possibly because plants had died and Zn leached out of the algal cells. The relationship between internal metal concentration and fluorescence was algal species and metal-specific.

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

    PubMed

    Vredenberg, Wim; Durchan, Milan; Prásil, Ondrej

    2009-12-01

    This paper deals with kinetics and properties of variable fluorescence in leaves and thylakoids upon excitation with low intensity multi-turnover actinic light pulses corresponding with an excitation rate of about 10 Hz. These show a relatively small and amply documented rise in the sub-s time range towards the plateau level F(pl) followed by a delayed and S-shaped rise towards a steady state level F(m) which is between three and four fold the initial dark fluorescence level F(o). Properties of this retarded slow rise are i) rate of dark recovery is (1-6 s)(-1), ii) suppression by low concentration of protonophores, iii) responsiveness to complementary single turnover flash excitation with transient amplitude towards a level F(m) which is between five and six fold the initial dark fluorescence level F(o) and iv) in harmony with and quantitatively interpretable in terms of a release of photoelectrochemical quenching controlled by the trans-thylakoid proton pump powered by the light-driven Q cycle. Data show evidence for a sizeable fluorescence increase upon release of (photo) electrochemical quenching, defined as qPE. Release of qPE occurs independent of photochemical quenching defined here as qPP even under conditions at which qPP = 1. The term photochemical quenching, hitherto symbolized by qP, will require a new definition, because it incorporates in its present form a sizeable photoelectrochemical component. The same is likely to be true for definition and use of qN as an indicator of non photochemical quenching.

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

    PubMed

    Murchie, E H; Lawson, T

    2013-10-01

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

  1. Algal photosynthetic responses to toxic metals and herbicides assessed by chlorophyll a fluorescence.

    PubMed

    Kumar, K Suresh; Dahms, Hans-Uwe; Lee, Jae-Seong; Kim, Hyung Chul; Lee, Won Chan; Shin, Kyung-Hoon

    2014-06-01

    Chlorophyll a fluorescence is established as a rapid, non-intrusive technique to monitor photosynthetic performance of plants and algae, as well as to analyze their protective responses. Apart from its utility in determining the physiological status of photosynthesizers in the natural environment, chlorophyll a fluorescence-based methods are applied in ecophysiological and toxicological studies to examine the effect of environmental changes and pollutants on plants and algae (microalgae and seaweeds). Pollutants or environmental changes cause alteration of the photosynthetic capacity which could be evaluated by fluorescence kinetics. Hence, evaluating key fluorescence parameters and assessing photosynthetic performances would provide an insight regarding the probable causes of changes in photosynthetic performances. This technique quintessentially provides non-invasive determination of changes in the photosynthetic apparatus prior to the appearance of visible damage. It is reliable, economically feasible, time-saving, highly sensitive, versatile, accurate, non-invasive and portable; thereby comprising an excellent alternative for detecting pollution. The present review demonstrates the applicability of chlorophyll a fluorescence in determining photochemical responses of algae exposed to environmental toxicants (such as toxic metals and herbicides). Copyright © 2014 Elsevier Inc. All rights reserved.

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

    PubMed Central

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

    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 angle and the plant height. The method fails with wilted plants when leaves overlap obscuring their true area. This effect, naturally, also interferes when the method is applied to measure plant growth under water stress. The method is, however, very potent in capturing the plant dynamics under mild stress and without stress. The 3D reconstruction is also highly effective in correcting geometrical factors that distort measurements of chlorophyll fluorescence emission of naturally positioned plant leaves. PMID:22368511

  3. Computer reconstruction of plant growth and chlorophyll fluorescence emission in three spatial dimensions.

    PubMed

    Bellasio, Chandra; Olejníčková, Julie; Tesař, Radek; Sebela, David; Nedbal, Ladislav

    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 angle and the plant height. The method fails with wilted plants when leaves overlap obscuring their true area. This effect, naturally, also interferes when the method is applied to measure plant growth under water stress. The method is, however, very potent in capturing the plant dynamics under mild stress and without stress. The 3D reconstruction is also highly effective in correcting geometrical factors that distort measurements of chlorophyll fluorescence emission of naturally positioned plant leaves.

  4. Plant chlorophyll fluorescence: active and passive measurements at canopy and leaf scales with different nitrogen treatments

    PubMed Central

    Cendrero-Mateo, M. Pilar; Moran, M. Susan; Papuga, Shirley A.; Thorp, K.R.; Alonso, L.; Moreno, J.; Ponce-Campos, G.; Rascher, U.; Wang, G.

    2016-01-01

    Most studies assessing chlorophyll fluorescence (ChlF) have examined leaf responses to environmental stress conditions using active techniques. Alternatively, passive techniques are able to measure ChlF at both leaf and canopy scales. However, the measurement principles of both techniques are different, and only a few datasets concerning the relationships between them are reported in the literature. In this study, we investigated the potential for interchanging ChlF measurements using active techniques with passive measurements at different temporal and spatial scales. The ultimate objective was to determine the limits within which active and passive techniques are comparable. The results presented in this study showed that active and passive measurements were highly correlated over the growing season across nitrogen treatments at both canopy and leaf-average scale. At the single-leaf scale, the seasonal relation between techniques was weaker, but still significant. The variability within single-leaf measurements was largely related to leaf heterogeneity associated with variations in CO2 assimilation and stomatal conductance, and less so to variations in leaf chlorophyll content, leaf size or measurement inputs (e.g. light reflected and emitted by the leaf and illumination conditions and leaf spectrum). This uncertainty was exacerbated when single-leaf analysis was limited to a particular day rather than the entire season. We concluded that daily measurements of active and passive ChlF at the single-leaf scale are not comparable. However, canopy and leaf-average active measurements can be used to better understand the daily and seasonal behaviour of passive ChlF measurements. In turn, this can be used to better estimate plant photosynthetic capacity and therefore to provide improved information for crop management. PMID:26482242

  5. Plant chlorophyll fluorescence: active and passive measurements at canopy and leaf scales with different nitrogen treatments.

    PubMed

    Cendrero-Mateo, M Pilar; Moran, M Susan; Papuga, Shirley A; Thorp, K R; Alonso, L; Moreno, J; Ponce-Campos, G; Rascher, U; Wang, G

    2016-01-01

    Most studies assessing chlorophyll fluorescence (ChlF) have examined leaf responses to environmental stress conditions using active techniques. Alternatively, passive techniques are able to measure ChlF at both leaf and canopy scales. However, the measurement principles of both techniques are different, and only a few datasets concerning the relationships between them are reported in the literature. In this study, we investigated the potential for interchanging ChlF measurements using active techniques with passive measurements at different temporal and spatial scales. The ultimate objective was to determine the limits within which active and passive techniques are comparable. The results presented in this study showed that active and passive measurements were highly correlated over the growing season across nitrogen treatments at both canopy and leaf-average scale. At the single-leaf scale, the seasonal relation between techniques was weaker, but still significant. The variability within single-leaf measurements was largely related to leaf heterogeneity associated with variations in CO2 assimilation and stomatal conductance, and less so to variations in leaf chlorophyll content, leaf size or measurement inputs (e.g. light reflected and emitted by the leaf and illumination conditions and leaf spectrum). This uncertainty was exacerbated when single-leaf analysis was limited to a particular day rather than the entire season. We concluded that daily measurements of active and passive ChlF at the single-leaf scale are not comparable. However, canopy and leaf-average active measurements can be used to better understand the daily and seasonal behaviour of passive ChlF measurements. In turn, this can be used to better estimate plant photosynthetic capacity and therefore to provide improved information for crop management. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  6. Fluorescent chlorophyll catabolites in bananas light up blue halos of cell death.

    PubMed

    Moser, Simone; Müller, Thomas; Holzinger, Andreas; Lütz, Cornelius; Jockusch, Steffen; Turro, Nicholas J; Kräutler, Bernhard

    2009-09-15

    Breakdown of chlorophyll is a major contributor to the diagnostic color changes in fall leaves, and in ripening apples and pears, where it commonly provides colorless, nonfluorescent tetrapyrroles. In contrast, in ripening bananas (Musa acuminata) chlorophylls fade to give unique fluorescent catabolites (FCCs), causing yellow bananas to glow blue, when observed under UV light. Here, we demonstrate the capacity of the blue fluorescent chlorophyll catabolites to signal symptoms of programmed cell death in a plant. We report on studies of bright blue luminescent rings on the peel of very ripe bananas, which arise as halos around necrotic areas in 'senescence associated' dark spots. These dark spots appear naturally on the peel of ripe bananas and occur in the vicinity of stomata. Wavelength, space, and time resolved fluorescence measurements allowed the luminescent areas to be monitored on whole bananas. Our studies revealed an accumulation of FCCs in luminescent rings, within senescing cells undergoing the transition to dead tissue, as was observable by morphological textural cellular changes. FCCs typically are short lived intermediates of chlorophyll breakdown. In some plants, FCCs are uniquely persistent, as is seen in bananas, and can thus be used as luminescent in vivo markers in tissue undergoing senescence. While FCCs still remain to be tested for their own hypothetical physiological role in plants, they may help fill the demand for specific endogenous molecular reporters in noninvasive assays of plant senescence. Thus, they allow for in vivo studies, which provide insights into critical stages preceding cell death.

  7. Fluorescent chlorophyll catabolites in bananas light up blue halos of cell death

    PubMed Central

    Moser, Simone; Müller, Thomas; Holzinger, Andreas; Lütz, Cornelius; Jockusch, Steffen; Turro, Nicholas J.; Kräutler, Bernhard

    2009-01-01

    Breakdown of chlorophyll is a major contributor to the diagnostic color changes in fall leaves, and in ripening apples and pears, where it commonly provides colorless, nonfluorescent tetrapyrroles. In contrast, in ripening bananas (Musa acuminata) chlorophylls fade to give unique fluorescent catabolites (FCCs), causing yellow bananas to glow blue, when observed under UV light. Here, we demonstrate the capacity of the blue fluorescent chlorophyll catabolites to signal symptoms of programmed cell death in a plant. We report on studies of bright blue luminescent rings on the peel of very ripe bananas, which arise as halos around necrotic areas in ‘senescence associated’ dark spots. These dark spots appear naturally on the peel of ripe bananas and occur in the vicinity of stomata. Wavelength, space, and time resolved fluorescence measurements allowed the luminescent areas to be monitored on whole bananas. Our studies revealed an accumulation of FCCs in luminescent rings, within senescing cells undergoing the transition to dead tissue, as was observable by morphological textural cellular changes. FCCs typically are short lived intermediates of chlorophyll breakdown. In some plants, FCCs are uniquely persistent, as is seen in bananas, and can thus be used as luminescent in vivo markers in tissue undergoing senescence. While FCCs still remain to be tested for their own hypothetical physiological role in plants, they may help fill the demand for specific endogenous molecular reporters in noninvasive assays of plant senescence. Thus, they allow for in vivo studies, which provide insights into critical stages preceding cell death. PMID:19805212

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  9. Global and time-resolved monitoring of crop photosynthesis with chlorophyll fluorescence.

    PubMed

    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

    2014-04-08

    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.

  10. Global and time-resolved monitoring of crop photosynthesis with chlorophyll fluorescence

    PubMed Central

    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. PMID:24706867

  11. Assimilation of remotely sensed chlorophyll fluorescence data into the land surface model CLM4

    NASA Astrophysics Data System (ADS)

    Wieneke, S.; Ahrends, H. E.; Rascher, U.; Schween, J.; Schickling, A.; Crewell, S.

    2013-12-01

    Photosynthesis is the most important exchange process of CO2 between the atmosphere and the land-surface. Therefore, the prediction of vegetation response to environmental conditions like increasing CO2 concentrations or plant stress is crucial for a reliable prediction of climate change. Photosynthesis is a complex physiological process that consists of numerous bio-physical sub-processes and chemical reactions. Spatial and temporal patterns of photosynthesis depend on dynamic plant-specific adaptation strategies to highly variable environmental conditions. Photosynthesis can be estimated using land-surface models, but, while state-of-the-art models often rely on Plant Functional Type (PFT) specific constants, they poorly simulate the dynamic adaptation of the physiological status of plant canopies in space and time. Remotely sensed sun-induced chlorophyll fluorescence (SICF) gives us now the possibility to estimate the diurnal dynamic vitality of the photosynthetic apparatus at both, the leaf and canopy levels. We installed within the framework of the Transregio32 project (www.tr32.de) automated hyperspectral fluorescence sensors at an agricultural site (winter wheat) in the Rur catchment area in West Germany at the end of July 2012. End of August, additional measurements of SIFC on nearby temperate grassland site (riparian meadow) and on a sugar beet field were performed. Spatial covering SICF data of the region were obtained during a measurement campaign using the newly developed air-borne hyperspectral sensor HyPlant on the 23 and 27 August 2012. SIFC data and data provided by eddy covariance measurements will be used to update certain model parameters that are normally set as constants. First model results demonstrate that the assimilation of SIFC into the Community Land Model 4 (CLM4) will result in a more realistic simulation of plant-specific adaptation strategies and therefore in a more realistic simulation of photosynthesis in space and time.

  12. Carotenoid-chlorophyll coupling and fluorescence quenching correlate with protein packing density in grana-thylakoids.

    PubMed

    Holleboom, Christoph-Peter; Yoo, Sunny; Liao, Pen-Nan; Compton, Ian; Haase, Winfried; Kirchhoff, Helmut; Walla, Peter Jomo

    2013-09-26

    The regulation of light-harvesting in photosynthesis under conditions of varying solar light irradiation is essential for the survival and fitness of plants and algae. It has been proposed that rearrangements of protein distribution in the stacked grana region of thylakoid membranes connected to changes in the electronic pigment-interaction play a key role for this regulation. In particular, carotenoid-chlorophyll interactions seem to be crucial for the down-regulation of photosynthetic light-harvesting. So far, it has been difficult to determine the influence of the dense protein packing found in native photosynthetic membrane on these interactions. We investigated the changes of the electronic couplings between carotenoids and chlorophylls and the quenching in grana thylakoids of varying protein packing density by two-photon spectroscopy, conventional chlorophyll fluorometry, low-temperature fluorescence spectroscopy, and electron micrographs of freeze-fracture membranes. We observed an increasing carotenoid-chlorophyll coupling and fluorescence quenching with increasing packing density. Simultaneously, the antennas size and excitonic connectivity of Photosystem II increased with increasing quenching and carotenoid-chlorophyll coupling whereas isolated, decoupled LHCII trimers decreased. Two distinct quenching data regimes could be identified that show up at different protein packing densities. In the regime corresponding to higher protein packing densities, quenching is strongly correlated to carotenoid-chlorophyll interactions whereas in the second regime, a weak correlation is apparent with low protein packing densities. Native membranes are in the strong-coupling data regime. Consequently, PSII and LHCII in grana membranes of plants are already quenched by protein crowding. We concluded that this ensures efficient electronic connection of all pigment-protein complexes for intermolecular energy transfer to the reaction centers and allows simultaneously

  13. [Effects of soil acidity on Pinus resinosa seedlings photosynthesis and chlorophyll fluorescence].

    PubMed

    Liu, Shuang; Wang, Qing-cheng; Liu, Ya-li; Tian, Yu-ming; Sun, Jing; Xu, Jing

    2009-12-01

    Red pine (Pinus resinosa) is one of the most important tree species for timber plantation in North America, and preliminary success has been achieved in its introduction to the mountainous area of Northeast China since 2004. In order to expand its growth area in other parts of Northeast China, a pot experiment was conducted to study the adaptability of this tree species to varying soil acidity. P. resinosa seedlings were grown in soils with different acidity (pH = 4.5, 5.5, 6.5, 7.5, and 8.0) to test the responses of their photosynthesis and chlorophyll fluorescence parameters to soil pH levels, and the appropriate soil acidity was evaluated. Dramatic responses in chlorophyll a and b contents, Pn and chlorophyll fluorescence parameters (Fo, Fm, Fv, Fv/Fm, and phi(PS II)) were detected under different soil acidity (P < 0.05), with the highest chlorophyll content and Pn under soil pH 5.5, and significantly lower chlorophyll content and Pn under soil pH 7.5 and 8.0. The chlorophyll content and Pn were 41% and 50%, and 61% and 88% higher under soil pH 5.5 than under soil pH 7.5 and 8.0. The seedlings had a significant photosynthetic inhibition under soil pH 7.5 and 8.0, but the highest Fv/Fm and phi (PS II) under soil pH 5.5. Comparing with those under soil pH 7.5 and 8.0, the Fv/Fm and phi (PS II) under soil pH 5.5 were 8% and 12%, and 22% and 35% higher, respectively. It was suggested that soil pH 5.5 was most appropriate for P. resinosa growth.

  14. Mapping cropland GPP in the north temperate region with space measurements of chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    Guanter, L.; Zhang, Y.; Jung, M.; Joiner, J.; Voigt, M.; Huete, A. R.; Zarco-Tejada, P.; Frankenberg, C.; Lee, J.; Berry, J. A.; Moran, S. M.; Ponce-Campos, G.; Beer, C.; Camps-Valls, G.; Buchmann, N. C.; Gianelle, D.; Klumpp, K.; Cescatti, A.; Baker, J. M.; Griffis, T.

    2013-12-01

    Monitoring agricultural productivity is important for optimizing management practices in a world under a continuous increase of food and biofuel demand. We used new space measurements of sun-induced chlorophyll fluorescence (SIF), a vegetation parameter intrinsically linked to photosynthesis, to capture photosynthetic uptake of the crop belts in the north temperate region. The following data streams and procedures have been used in this analysis: (1) SIF retrievals have been derived from measurements of the MetOp-A / GOME-2 instrument in the 2007-2011 time period; (2) ensembles of process-based and data-driven biogeochemistry models have been analyzed in order to assess the capability of global models to represent crop gross primary production (GPP); (3) flux tower-based GPP estimates covering the 2007-2011 time period have been extracted over 18 cropland and grassland sites in the Midwest US and Western Europe from the Ameriflux and the European Fluxes Database networks; (4) large-scale NPP estimates have been derived by the agricultural inventory data sets developed by USDA-NASS and Monfreda et al. The strong linear correlation between the SIF space retrievals and the flux tower-based GPP, found to be significantly higher than that between reflectance-based vegetation indices (EVI, NDVI and MTCI) and GPP, has enabled the direct upscaling of SIF to cropland GPP maps at the synoptic scale. The new crop GPP estimates we derive from the scaling of SIF space retrievals are consistent with both flux tower GPP estimates and agricultural inventory data. These new GPP estimates show that crop productivity in the US Western Corn Belt, and most likely also in the rice production areas in the Indo-Gangetic plain and China, is up to 50-75% higher than estimates by state-of-the-art data-driven and process-oriented biogeochemistry models. From our analysis we conclude that current carbon models have difficulties in reproducing the special conditions of those highly productive

  15. Chlorophyll-a determination via continuous measurement of plankton fluorescence: methodology development.

    PubMed

    Pinto, A M; Von Sperling, E; Moreira, R M

    2001-11-01

    A methodology is presented for the continuous measurement of chlorophyll-a concentration due to plankton, in surface water environments. A Turner 10-AU fluorometer equipped with the F4T5.B2/BP lamp (blue lamp), a Cs 5-60 equivalent excitation path filter, and a 680 nm emission filter, has been used. This configuration allows the in vivo, in situ determination of chlorophyll-a by measuring the fluorescence due to the pigments. In field work the fluorometer, data logging and positioning equipment were placed aboard a manageable boat which navigated following a scheme of regularly spaced crossings. Some water samples were collected during the measurement for laboratory chlorophyll-a measurements by the spectrophotometric method, thus providing for calibration and comparison. Spatial chlorophyll-a concentration distributions can be easily defined in large volumes, such as reservoirs, etc. Two distinct environments have been monitored: in the Vargem das Flores reservoir chlorophyll-a concentrations varied between 0.7 and 2.6 mg/m3, whereas in the Lagoa Santa lake these values lied in the 12 to 18 mg/m3 range. The simplicity, versatility and economy of the method, added to the large amount of data that can be gathered in a single run, clearly justify its use in field environmental studies.

  16. Simultaneous Measurement of Oscillations in Oxygen Evolution and Chlorophyll a Fluorescence in Leaf Pieces 1

    PubMed Central

    Walker, David A.; Sivak, Mirta N.; Prinsley, Roslyn T.; Cheesbrough, John K.

    1983-01-01

    In spinach (Spinacia oleracea) and barley (Hordeum vulgare) leaves, chlorophyll a fluorescence and O2 evolution have been measured simultaneously following re-illumination after a dark interval or when steady state photosynthesis has been perturbed by changes in the gas phase. In high CO2 concentrations, both O2 and fluorescence can display marked dampening oscillations that are antiparallel but slightly out of phase (a rise or fall in fluorescence anticipating a corresponding fall or rise in O2 by about 10 to 15 seconds). Infrared gas analysis measurements showed that CO2 uptake behaved like O2 evolution both in the period of oscillation (about 1 minute) and in its relation to fluorescence. In the steady state, oscillations were initiated by increases in CO2 or by increases or decreases in O2. Oscillations in O2 or CO2 did not occur without associated oscillations in fluorescence and the latter were a sensitive indicator of the former. The relationship between such oscillations in photosynthetic carbon assimilation and chlorophyl a fluorescence is discussed in the context of the effect of ATP or NADPH consumption on known quenching mechanisms. PMID:16663255

  17. Simultaneous measurement of oscillations in oxygen evolution and chlorophyll a fluorescence in leaf pieces.

    PubMed

    Walker, D A; Sivak, M N; Prinsley, R T; Cheesbrough, J K

    1983-11-01

    In spinach (Spinacia oleracea) and barley (Hordeum vulgare) leaves, chlorophyll a fluorescence and O(2) evolution have been measured simultaneously following re-illumination after a dark interval or when steady state photosynthesis has been perturbed by changes in the gas phase. In high CO(2) concentrations, both O(2) and fluorescence can display marked dampening oscillations that are antiparallel but slightly out of phase (a rise or fall in fluorescence anticipating a corresponding fall or rise in O(2) by about 10 to 15 seconds). Infrared gas analysis measurements showed that CO(2) uptake behaved like O(2) evolution both in the period of oscillation (about 1 minute) and in its relation to fluorescence. In the steady state, oscillations were initiated by increases in CO(2) or by increases or decreases in O(2). Oscillations in O(2) or CO(2) did not occur without associated oscillations in fluorescence and the latter were a sensitive indicator of the former. The relationship between such oscillations in photosynthetic carbon assimilation and chlorophyl a fluorescence is discussed in the context of the effect of ATP or NADPH consumption on known quenching mechanisms.

  18. CO2, CH4, CO and Chlorophyll Fluorescence Retrievals for the Geostationary Carbon Process Investigation

    NASA Astrophysics Data System (ADS)

    Xi, X.; Natraj, V.; Luo, M.; Shia, R.; Sander, S. P.; Yung, Y. L.

    2013-12-01

    The Geostationary Carbon Process Investigation (GCPI) combines an imaging Fourier Transform Spectrometer instrument with a geostationary Earth orbit vantage point to realize a transformational advance in carbon monitoring beyond the synoptic capabilities of Low Earth Orbit instruments such as SCIAMACHY, GOSAT and OCO-2. GCPI follows the paradigm of numerical weather prediction and aims to provide orders of magnitude improvement in observational density for atmospheric CO2, CH4, CO, and new measurements of chlorophyll fluorescence (CF). These new observations could be used to drive and constrain Earth system models, improve our understanding of the underlying carbon cycle processes and evaluate model forecasting capabilities. GCPI is designed to deliver simultaneous measurements of CF and column averaged CO2, CH4 and CO dry air mole fractions to disentangle biogenic and anthropogenic sources of carbon. Here, we perform radiative transfer simulations over a range of conditions expected to be observed by GCPI and estimate prospective performance of retrievals based on results from Bayesian error analysis and characterizations. The potential benefits from the measurements of CF are also investigated.

  19. [Estimation of forest canopy chlorophyll content based on PROSPECT and SAIL models].

    PubMed

    Yang, Xi-guang; Fan, Wen-yi; Yu, Ying

    2010-11-01

    The forest canopy chlorophyll content directly reflects the health and stress of forest. The accurate estimation of the forest canopy chlorophyll content is a significant foundation for researching forest ecosystem cycle models. In the present paper, the inversion of the forest canopy chlorophyll content was based on PROSPECT and SAIL models from the physical mechanism angle. First, leaf spectrum and canopy spectrum were simulated by PROSPECT and SAIL models respectively. And leaf chlorophyll content look-up-table was established for leaf chlorophyll content retrieval. Then leaf chlorophyll content was converted into canopy chlorophyll content by Leaf Area Index (LAD). Finally, canopy chlorophyll content was estimated from Hyperion image. The results indicated that the main effect bands of chlorophyll content were 400-900 nm, the simulation of leaf and canopy spectrum by PROSPECT and SAIL models fit better with the measured spectrum with 7.06% and 16.49% relative error respectively, the RMSE of LAI inversion was 0. 542 6 and the forest canopy chlorophyll content was estimated better by PROSPECT and SAIL models with precision = 77.02%.

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

    NASA Astrophysics Data System (ADS)

    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 (< 1 nm, between 750-770 nm) of the near infrared (NIR) region of Earth's reflected radiation have been achieved from satellites, including the Japanese GOSAT and the European Space Agency's Sciamachy/Envisat. However, these retrievals 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

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

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

  2. Photoprotective function of chloroplast avoidance movement: in vivo chlorophyll fluorescence study.

    PubMed

    Sztatelman, Olga; Waloszek, Andrzej; Banaś, Agnieszka Katarzyna; Gabryś, Halina

    2010-06-15

    Light-induced chloroplast avoidance movement has long been considered to be a photoprotective mechanism. Here, we present an experimental model in which this function can be shown for wild type Arabidopsis thaliana. We used blue light of different fluence rates for chloroplast positioning, and strong red light inactive in chloroplast positioning as a stressing light. The performance of photosystem II was measured by means of chlorophyll fluorescence. After stressing light treatment, a smaller decrease in photosystem II quantum yield was observed for leaves with chloroplasts in profile position as compared with leaves with chloroplasts in face position. Three Arabidopsis mutants, phot2 (no avoidance response), npq1 (impaired zeaxanhtin accumulation) and stn7 (no state transition), were examined for their chloroplast positioning and chlorophyll fluorescence parameters under identical experimental conditions. The results obtained for these mutants revealed additional stressing effects of blue light as compared with red light.

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

    PubMed Central

    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 (Fv/Fm). A seasonal dip - as well as a larger variation - of Fv/Fm in spring compared to the rest of the year was observed. Over the year, the upper leaves of the plant perform better than the bottom leaves. These findings were linked to environmental factors such as light intensity, air temperature and precipitation, as increased light intensities, decreasing air temperatures and their interactions, also with precipitation levels have an effect on the photosynthetic efficiency (Fv/Fm) in these plants. PMID:23967282

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

    SciTech Connect

    Nordlund, T.M.; Knox, W.H.

    1981-10-01

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

  5. [Chlorophyll fluorescence spectrum analysis of greenhouse cucumber disease and insect damage].

    PubMed

    Sui, Yuan-yuan; Yu, Hai-ye; Zhang, Lei; Luo, Han; Ren, Shun; Zhao, Guo-gang

    2012-05-01

    The present paper is based on chlorophyll fluorescence spectrum analysis. The wavelength 685 nm was determined as the primary characteristic point for the analysis of healthy or disease and insect damaged leaf by spectrum configuration. Dimensionality reduction of the spectrum was achieved by combining simple intercorrelation bands selection and principal component analysis (PCA). The principal component factor was reduced from 10 to 5 while the spectrum information was kept reaching 99.999%. By comparing and analysing three modeling methods, namely the partial least square regression (PLSR), BP neural network (BP) and least square support vector machine regression (LSSVMR), regarding correlation coefficient of true value and predicted value as evaluation criterion, eventually, LSSVMR was confirmed as the appropriate method for modeling of greenhouse cucumber disease and insect damage chlorophyll fluorescence spectrum analysis.

  6. Photosynthetic properties of spring geophytes assessed by chlorophyll fluorescence analysis.

    PubMed

    Recchia, Irene; Sparla, Francesca; Pupillo, Paolo

    2017-09-01

    Since spring ephemerals are credited to be all "sun" species with unusually elevate photosynthesis, in contrast to shade-tolerant trees and understory geophytes with a long aboveground cycle, we examined the photosynthetic efficiency of 6 woody species, 9 long-cycle geophytes, and 8 spring ephemeral geophytes using blue flashes of increasing energy with the Imaging PAM fluorometer. Several parameters were obtained: quantum yield of electron transport (ΦETR) or of PSII (ΦPSII), maximum measured photosynthesis rate (ETRhv), maximum extrapolated rate of photosynthesis (ETRem), half-saturating photon flux density (KPAR), and in some cases photochemical (qP) and non-photochemical quenching (NPQ). Results confirm the ecological consistency of the three plant groups, with internal differences. Woody species have low ETRem and KPAR values with good ΦETR; long-cycle herbs have low ETRem and ΦETR and moderate KPAR values; spring ephemerals have elevate ΦETR, ETRem and KPAR values. The mean ETRem of ephemerals of 91 μmol m(-2) s(-1) exceeds that of long-cycle herbs 2.9-fold and woody species 4.8-fold, and corresponds to 19 μmol CO2 m(-2) s(-1) by assuming an ETR/ΦCO2 ratio of 4.7. Highest photosynthesis rates and KPAR were exhibited by five ephemerals (Eranthis, Erythronium, Narcissus, Scilla, Tulipa) with peak ETRem values equivalent to ∼40 μmol CO2 m(-2) s(-1) or ∼60 μmol CO2 (g Chl)(-1) s(-1) ("sun" species). According to a new, fluorescence based heliophily index, all trees and five long-cycle herbs were definitely "shade" species, while four long-cycle herbs and three ephemerals were intermediate shade-tolerant. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

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

    PubMed

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

    2015-06-01

    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. 200 µmol m(-2)  s(-1) at plant height for 14 h per day and 24/18°C day/night temperature, respectively, from January to April 2013. The light treatments were (1) 40% blue in 60% red (40% B/R), (2) 0% blue in 100% red (0% B/R) and (3) white LEDs with 32% blue in white (32% B/W, control), with background daylight under shade screens. The plants were harvested twice for leaf growth and pigmentation. There was no clear pattern in the spectral effect on growth since the order of leaf size differed between harvests in March and April. Fv /Fm was in the range of 0.52-0.72, but overall slightly higher in the control, which indicated a permanent downregulation of PSII in the colored treatments. The fluorescence quenching showed no acclimation to color in 'Purple Star', while 'Vivien' had lower ETR and higher NPQ in the 40% B/R, resembling low light acclimation. The pigmentation showed corresponding spectral response with increasing concentration of lutein while increasing the fraction of blue light, which increased the light absorption in the green/yellow part of the spectrum. The permanent downregulation of PSII moved a substantial part of the thermal dissipation from the light regulated NPQ to non-regulated energy losses estimated by ΦNPQ and ΦNO and the difference found in the balance between ΦPSII and ΦNPQ in 'Vivien' disappeared when ΦNO was included in the thermal dissipation. © 2014 Scandinavian Plant Physiology Society.

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

    PubMed

    Mishra, Kumud Bandhu; Iannacone, Rina; Petrozza, Angelo; Mishra, Anamika; Armentano, Nadia; La Vecchia, Giovanna; Trtílek, Martin; Cellini, Francesco; Nedbal, Ladislav

    2012-01-01

    Drought stress is one of the most important factors that limit crop productivity worldwide. In order to obtain tomato plants with enhanced drought tolerance, we inserted the transcription factor gene ATHB-7 into the tomato genome. This gene was demonstrated earlier to be up-regulated during drought stress in Arabidopsis thaliana thus acting as a negative regulator of growth. We compared the performance of wild type and transgenic tomato line DTL-20, carrying ATHB-7 gene, under well-irrigated and water limited conditions. We found that transgenic plants had reduced stomatal density and stomatal pore size and exhibited an enhanced resistance to soil water deficit. We used the transgenic plants to investigate the potential of chlorophyll fluorescence to report drought tolerance in a simulated high-throughput screening procedure. Wild type and transgenic tomato plants were exposed to drought stress lasting 18 days. The stress was then terminated by rehydration after which recovery was studied for another 2 days. Plant growth, leaf water potential, and chlorophyll fluorescence were measured during the entire experimental period. We found that water potential in wild type and drought tolerant transgenic plants diverged around day 11 of induced drought stress. The chlorophyll fluorescence parameters: the non-photochemical quenching, effective quantum efficiency of PSII, and the maximum quantum yield of PSII photochemistry yielded a good contrast between wild type and transgenic plants from day 7, day 12, and day 14 of induced stress, respectively. We propose that chlorophyll fluorescence emission reports well on the level of water stress and, thus, can be used to identify elevated drought tolerance in high-throughput screens for selection of resistant genotypes.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

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

    PubMed

    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

    2016-07-22

    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

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

    PubMed Central

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

    2017-01-01

    In order to increase the monitoring capabilities of inland and coastal waters, there is a need for new, affordable, sensitive and mobile instruments that could be operated semi-automatically in the field. This paper presents a prototype device to measure chlorophyll a fluorescence: the SmartFluo. The device is a combination of a smartphone offering an intuitive operation interface and an adapter implying a cuvette holder, as well as a suitable illumination source. SmartFluo is based on stimulated fluorescence of water constituents such as chlorophyll a. The red band of the digital smartphone camera is sensitive enough to detect quantitatively the characteristic red fluorescence emission. The adapter contains a light source, a strong light emitting diode and additional filters to enhance the signal-to-noise ratio and to suppress the impact of scattering. A novel algorithm utilizing the red band of the camera is provided. Laboratory experiments of the SmartFluo show a linear correlation (R2 = 0.98) to the chlorophyll a concentrations measured by reference instruments, such as a high-performance benchtop laboratory fluorometer (LS 55, PerkinElmer). PMID:28346338

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

    PubMed

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

    2017-03-25

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

  14. A nondestructive method to estimate the chlorophyll content of Arabidopsis seedlings.

    PubMed

    Liang, Ying; Urano, Daisuke; Liao, Kang-Ling; Hedrick, Tyson L; Gao, Yajun; Jones, Alan M

    2017-01-01

    Chlorophyll content decreases in plants under stress conditions, therefore it is used commonly as an indicator of plant health. Arabidopsis thaliana offers a convenient and fast way to test physiological phenotypes of mutations and treatments. However, chlorophyll measurements with conventional solvent extraction are not applicable to Arabidopsis leaves due to their small size, especially when grown on culture dishes. We provide a nondestructive method for chlorophyll measurement whereby the red, green and blue (RGB) values of a color leaf image is used to estimate the chlorophyll content from Arabidopsis leaves. The method accommodates different profiles of digital cameras by incorporating the ColorChecker chart to make the digital negative profiles, to adjust the white balance, and to calibrate the exposure rate differences caused by the environment so that this method is applicable in any environment. We chose an exponential function model to estimate chlorophyll content from the RGB values, and fitted the model parameters with physical measurements of chlorophyll contents. As proof of utility, this method was used to estimate chlorophyll content of G protein mutants grown on different sugar to nitrogen ratios. This method is a simple, fast, inexpensive, and nondestructive estimation of chlorophyll content of Arabidopsis seedlings. This method lead to the discovery that G proteins are important in sensing the C/N balance to control chlorophyll content in Arabidopsis.

  15. A nondestructive method to estimate the chlorophyll content of Arabidopsis seedlings

    DOE PAGES

    Liang, Ying; Urano, Daisuke; Liao, Kang-Ling; ...

    2017-04-14

    Chlorophyll content decreases in plants under stress conditions, therefore it is used commonly as an indicator of plant health. Arabidopsis thaliana offers a convenient and fast way to test physiological phenotypes of mutations and treatments. But, chlorophyll measurements with conventional solvent extraction are not applicable to Arabidopsis leaves due to their small size, especially when grown on culture dishes. We provide a nondestructive method for chlorophyll measurement whereby the red, green and blue (RGB) values of a color leaf image is used to estimate the chlorophyll content from Arabidopsis leaves. The method accommodates different profiles of digital cameras by incorporatingmore » the ColorChecker chart to make the digital negative profiles, to adjust the white balance, and to calibrate the exposure rate differences caused by the environment so that this method is applicable in any environment. We chose an exponential function model to estimate chlorophyll content from the RGB values, and fitted the model parameters with physical measurements of chlorophyll contents. As further proof of utility, this method was used to estimate chlorophyll content of G protein mutants grown on different sugar to nitrogen ratios. Our method is a simple, fast, inexpensive, and nondestructive estimation of chlorophyll content of Arabidopsis seedlings. This method lead to the discovery that G proteins are important in sensing the C/N balance to control chlorophyll content in Arabidopsis.« less

  16. Relationship between photosynthetic pigments and chlorophyll fluorescence in soybean under varying phosphorus nutrition at ambient and elevated CO2

    USDA-ARS?s Scientific Manuscript database

    Photosynthetic pigments such as chlorophyll (Chl) a, Chl b and carotenoids concentration, and chlorophyll fluorescence (CF) have widely been used as indicators of stress and photosynthetic performance in plants. Although photosynthetic pigments and CF are partly interdependent due to absorption and ...

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

    Lee, Jung-Eun; Frankenberg, Christian; van der Tol, Christiaan; Berry, Joseph A.; Guanter, Luis; Boyce, C. Kevin; Fisher, Joshua B.; Morrow, Eric; Worden, John R.; Asefi, Salvi; Badgley, Grayson; Saatchi, Sassan

    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 QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r2 = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r2 = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009. PMID:23760636

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

    PubMed

    Lee, Jung-Eun; Frankenberg, Christian; van der Tol, Christiaan; Berry, Joseph A; Guanter, Luis; Boyce, C Kevin; Fisher, Joshua B; Morrow, Eric; Worden, John R; Asefi, Salvi; Badgley, Grayson; Saatchi, Sassan

    2013-06-22

    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 QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r(2) = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r(2) = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009.

  20. A model considering light reabsorption processes to correct in vivo chlorophyll fluorescence spectra in apples.

    PubMed

    Ramos, María E; Lagorio, María G

    2006-05-01

    Chlorophyll-a contained in the peel of Granny Smith apples emits fluorescence upon excitation with blue light. The observed emission, collected by an external detector and corrected by its spectral response, is still distorted by light reabsorption processes taking place in the fruit skin and differs appreciably from the true spectral distribution of fluorescence emerging from chlorophyll molecules in the biological tissue. Reabsorption processes particularly affect the ratio of fluorescence intensities at 680 nm and at 730 nm. A model to obtain the correct spectral distribution of the emission, from the experimental fluorescence recorded at a fluorometer detector and corrected for the detector spectral sensitivity, is developed in the present work. Measurements of the whole fruit reflectance, the peel transmittance and the flesh reflectance allow the calculation of the reabsorption-corrected spectra. The model is validated by comparing the corrected emission spectra with that obtained for a thin layer of apple-peel-chloroplasts, where no reabsorption takes place. It is recommended to correct distortions in emission spectra of intact fruits due to light reabsorption effects whenever a correlation between the physiological state of the fruit and its fluorescence spectra is investigated.

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

    NASA Astrophysics Data System (ADS)

    Liao, Pen-Nan; Bode, Stefan; Wilk, Laura; Hafi, Nour; Walla, Peter J.

    2010-07-01

    The aggregation dependent correlation between fluorescence quenching and the electronic carotenoid-chlorophyll interactions, ϕCouplingCar S-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 S-Chl and the fluorescence quenching was observed as previously reported for the pH and Zea-dependent quenching of LHC II [1]. 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.

  2. Mechanism of strong quenching of photosystem II chlorophyll fluorescence under drought stress in a lichen, Physciella melanchla, studied by subpicosecond fluorescence spectroscopy.

    PubMed

    Komura, Masayuki; Yamagishi, Atsushi; Shibata, Yutaka; Iwasaki, Ikuko; Itoh, Shigeru

    2010-03-01

    The mechanism of the severe quenching of chlorophyll (Chl) fluorescence under drought stress was studied in a lichen Physciella melanchla, which contains a photobiont green alga, Trebouxia sp., using a streak camera and a reflection-mode fluorescence up-conversion system. We detected a large 0.31 ps rise of fluorescence at 715 and 740 nm in the dry lichen suggesting the rapid energy influx to the 715-740 nm bands from the shorter-wavelength Chls with a small contribution from the internal conversion from Soret bands. The fluorescence, then, decayed with time constants of 23 and 112 ps, suggesting the rapid dissipation into heat through the quencher. The result confirms the accelerated 40 ps decay of fluorescence reported in another lichen (Veerman et al., 2007 [36]) and gives a direct evidence for the rapid energy transfer from bulk Chls to the longer-wavelength quencher. We simulated the entire PS II fluorescence kinetics by a global analysis and estimated the 20.2 ns(-1) or 55.0 ns(-1) energy transfer rate to the quencher that is connected either to the LHC II or to the PS II core antenna. The strong quenching with the 3-12 times higher rate compared to the reported NPQ rate, suggests the operation of a new type of quenching, such as the extreme case of Chl-aggregation in LHCII or a new type of quenching in PS II core antenna in dry lichens.

  3. [Spatio-temporal distribution of chlorophyll a concentration and its estimation in Taihu Lake].

    PubMed

    Le, Cheng-Feng; Li, Yun-Mei; Sun, De-Yong; Wang, Hai-Jun; Huang, Chang-Chun

    2008-03-01

    The temporal and spatial distribution of chlorophyll a concentration in Taihu Lake was analyzed using the data measured from January to October in 2005. Otherwise, chlorophyll a retrieval model was built using the synchronous spectrum data obtained in different season to evaluate the effect of chlorophyll a concentration temporal and spatial variation on the retrieval model. Firstly, temporal distribution of chlorophyll a concentration was analyzed. Then, chlorophyll a concentration was induced by Inverse Distance Weight method. Lastly, the chlorophyll a concentration estimation models based on spring, summer, autumn and different trophic states were built. An obvious spatial-temporal distribution was found for chlorophyll a concentration in Taihu. Chlorophyll a concentration had the maximal value in summer and the minimal value in winter,and the average chlorophyll a concentration was 56.29 microg/L, 13.61 microg/L respectively. Due to the effect of autumn, the average chlorophyll a concentration in autumn was higher than that in spring, and the average chlorophyll a concentration was 26.43 microg/L, 34.78 microg/L respectively. Marked spatial difference for chlorophyll a concentration was found in summer,while in winterthe spatial variation was ambiguous. The spatial variation in autumn was greater than that in spring as influenced by summer. Spatially, the variation in north area was greater than those in the other areas and the south area had less variation during the year. Because of the different chlorophyll a concentration, different season had different retrieval model. Band-ratio had better retrieval result in spring and autumn as there were lower concentration and less variation correspondingly. While in summer, because of the high chlorophyll a concentration and great spatial variation, among the arithmetic built in summer, the differential arithmetic was the optimal model, and the difference of Chl-a concentration retrieval model of different trophic

  4. [Winter wheat GPC estimation based on leaf and canopy chlorophyll parameters].

    PubMed

    Song, Xiao-Yu; Wang, Ji-Hua; Yang, Gui-Jun; Cui, Bei; Chang, Hong

    2014-07-01

    . The study reveals that SPAD value is a good indicator of single plant activity while SFR_G and SFR_R are better indicators for the wheat group activity. Wheat leaf SPAD value and canopy chlorophyll fluorescence information SFR are all feasible and valuable for GPC estimation before wheat harvesting.

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

    PubMed

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

    2017-09-21

    Estimating terrestrial gross primary production is an important task when studying the carbon cycle. In this study, the ability of a two-leaf light use efficiency model to simulate regional gross primary production in China was validated using satellite Global Ozone Monitoring Instrument - 2 sun-induced chlorophyll fluorescence data. The two-leaf light use efficiency model was used to estimate daily gross primary production in China's terrestrial ecosystems with 500-m resolution for the period from 2007 to 2014. Gross primary production simulated with the two-leaf light use efficiency model was resampled to a spatial resolution of 0.5° and then compared with sun-induced chlorophyll fluorescence. During the study period, sun-induced chlorophyll fluorescence and gross primary production simulated by the two-leaf light use efficiency model exhibited similar spatial and temporal patterns in China. The correlation coefficient between sun-induced chlorophyll fluorescence and monthly gross primary production simulated by the two-leaf light use efficiency model was significant (p<0.05, n=96) in 88.9% of vegetated areas in China (average value 0.78) and varied among vegetation types. The interannual variations in monthly sun-induced chlorophyll fluorescence and gross primary production simulated by the two-leaf light use efficiency model were similar in spring and autumn in most vegetated regions, but dissimilar in winter and summer. The spatial variability of sun-induced chlorophyll fluorescence and gross primary production simulated by the two-leaf light use efficiency model was similar in spring, summer, and autumn. The proportion of spatial variations of sun-induced chlorophyll fluorescence and annual gross primary production simulated by the two-leaf light use efficiency model explained by ranged from 0.76 (2011) to 0.80 (2013) during the study period. Overall, the two-leaf light use efficiency model was capable of capturing spatial and temporal variations in gross

  6. Quenching of chlorophyll fluorescence in the major light-harvesting complex of photosystem II: a systematic study of the effect of carotenoid structure.

    PubMed Central

    Phillip, D; Ruban, A V; Horton, P; Asato, A; Young, A J

    1996-01-01

    The role of carotenoids in quenching of chlorophyll fluorescence in the major light-harvesting complex of photosystem II has been studied with a view to understanding the molecular basis of the control of photoprotective nonradiative energy dissipation by the xanthophyll cycle in vivo. The control of chlorophyll fluorescence quenching in the isolated complex has been investigated in terms of the number of the conjugated double bonds for a series of carotenoids ranging from n = 5-19, giving an estimated first excited singlet state energy from 20,700 cm-1 to 10,120 cm-1. At pH 7.8 the addition of exogenous carotenoids with >=10 conjugated double bonds (including zeaxanthin) stimulated fluorescence quenching relative to the control with no added carotenoid, whereas those with n fluorescence. When quenching in the light-harvesting complex of photosystem II was induced by a lowering of pH to 5.5, carotenoids with n fluorescence quenching relative to the control. Of the 10 carotenoids tested, quenching induced by the addition of the tertiary amine compound, dibucaine, to isolated light-harvesting complex of photosystem II could only be reversed by violaxanthin. These results are discussed in terms of the two theories developed to explain the role of zeaxanthin and violaxanthin in nonphotochemical quenching of chlorophyll fluorescence. PMID:11607629

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    PubMed

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

    2011-10-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  10. Estimating chlorophyll content and bathymetry of Lake Tahoe using AVIRIS data

    NASA Technical Reports Server (NTRS)

    Hamilton, Michael K.; Davis, Curtiss O.; Rhea, W. J.; Pilorz, Stuart H.; Carder, Kendall L.

    1993-01-01

    Data on chlorophyll content and bathymetry of Lake Tahoe obtained on August 9, 1990 by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) are compared to concurrent in situ surface and in-water measurements. Measured parameters included profiles of percent transmission of monochromatic light, stimulated chlorophyll fluorescence, photosynthetically available radiation, spectral upwelling and downwelling irradiance, and upwelling radiance. Several analyses were performed illustrating the utility of the AVIRIS over a dark water scene. Image-derived chlorophyll concentration compared extremely well with that measured with bottle samples. A bathymetry map of the shallow parts of the lake was constructed which compares favorably with published lake soundings.

  11. Estimating chlorophyll content and bathymetry of Lake Tahoe using AVIRIS data

    NASA Technical Reports Server (NTRS)

    Hamilton, Michael K.; Davis, Curtiss O.; Rhea, W. J.; Pilorz, Stuart H.; Carder, Kendall L.

    1993-01-01

    Data on chlorophyll content and bathymetry of Lake Tahoe obtained on August 9, 1990 by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) are compared to concurrent in situ surface and in-water measurements. Measured parameters included profiles of percent transmission of monochromatic light, stimulated chlorophyll fluorescence, photosynthetically available radiation, spectral upwelling and downwelling irradiance, and upwelling radiance. Several analyses were performed illustrating the utility of the AVIRIS over a dark water scene. Image-derived chlorophyll concentration compared extremely well with that measured with bottle samples. A bathymetry map of the shallow parts of the lake was constructed which compares favorably with published lake soundings.

  12. Photochemical studies of a fluorescent chlorophyll catabolite--source of bright blue fluorescence in plant tissue and efficient sensitizer of singlet oxygen.

    PubMed

    Jockusch, Steffen; Turro, Nicholas J; Banala, Srinivas; Kräutler, Bernhard

    2014-02-01

    Fluorescent chlorophyll catabolites (FCCs) are fleeting intermediates of chlorophyll breakdown, which is seen as an enzyme controlled detoxification process of the chlorophylls in plants. However, some plants accumulate large amounts of persistent FCCs, such as in senescent leaves and in peels of yellow bananas. The photophysical properties of such a persistent FCC (Me-sFCC) were investigated in detail. FCCs absorb in the near UV spectral region and show blue fluorescence (max at 437 nm). The Me-sFCC fluorescence had a quantum yield of 0.21 (lifetime 1.6 ns). Photoexcited Me-sFCC intersystem crosses into the triplet state (quantum yield 0.6) and generates efficiently singlet oxygen (quantum yield 0.59). The efficient generation of singlet oxygen makes fluorescent chlorophyll catabolites phototoxic, but might also be useful as a (stress) signal and for defense of the plant tissue against infection by pathogens.

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Solar Induced Chlorophyll Fluorescence from the leaf through the global scale

    NASA Astrophysics Data System (ADS)

    Frankenberg, C.; Stutz, J.; Grossmann, K.; Drewry, D.; Geier, S.; Verma, M.; Sun, Y.; Magney, T. S.

    2016-12-01

    New satellite measurements from space as well as the FLEX mission have spurred research in the use of Solar Induced Chlorophyll Fluorescence (SIF) for investigations into the carbon cycle from the regional through the global scale. The Orbiting Carbon Observatory, launched in July 2014, now provides SIF data at unprecedented spatial resolution of less than 3km2. In addition, JPL built the airborne Chlorophyll Fluorescence Imaging Spectrometer (CFIS) for OCO-2 validation and local studies. For the local scale, the PhotoSpec project, funded by the Keck Institute for Space Studies and JPL now enables the acquisition of high resolution spectra on the ground at flux-tower sites. For the leaf level scale, we developed a system to combine Pulse Amplitude Modulated fluorescence measurements with spectrally resolved measurements of SIF and saturation pulse induced maximum fluorescence. This talk will summarize recent measurement advances for SIF, with a particular focus on the CFIS instrument and campaigns in 2015/2016 in the continental US.

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

    PubMed

    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.

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

    PubMed

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

    2016-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    PubMed

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

    2010-06-01

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

  19. Dualex: A New Instrument for Field Measurements of Epidermal Ultraviolet Absorbance by Chlorophyll Fluorescence

    NASA Astrophysics Data System (ADS)

    Goulas, Yves; Cerovic, Zoran G.; Cartelat, Aurélie; Moya, Ismaël

    2004-08-01

    Dualex (dual excitation) is a field-portable instrument, hereby described, for the assessment of polyphenolic compounds in leaves from the measurement of UV absorbance of the leaf epidermis by double excitation of chlorophyll fluorescence. The instrument takes advantage of a feedback loop that equalizes the fluorescence level induced by a reference red light to the UV-light-induced fluorescence level. This allows quick measurement from attached leaves even under field conditions. The use of light-emitting diodes and of a leaf-clip configuration makes Dualex a user-friendly instrument with potential applications in ecophysiological research, light climate analysis, agriculture, forestry, horticulture, pest management, selection of medicinal plants, and wherever accumulation of leaf polyphenolics is involved in plant responses to the environment.

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

    PubMed

    Janka, Eshetu; Körner, Oliver; Rosenqvist, Eva; Ottosen, Carl-Otto

    2013-06-01

    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 high temperature affects the plant photosynthetic responses, resulting in a lower rate of photosynthesis. To predict and analyse physiological responses as stress indicators, two independent experiments were conducted, to detect the effect of high temperature on photosynthesis: analysing photosystem II (PSII) and stomatal conductance (gs). A combination of chlorophyll a fluorescence, gas exchange measurements and infrared thermography was applied using Chrysanthemum (Dendranthema grandiflora Tzvelev) 'Coral Charm' as a model species. Increasing temperature had a highly significant effect on PSII when the temperature exceeded 38 °C for a period of 7 (±1.8) days. High temperature decreased the maximum photochemical efficiency of PSII (Fv/Fm), the conformation term for primary photochemistry (Fv/Fo) and performance index (PI), as well as increased minimal fluorescence (Fo). However, at elevated CO2 of 1000 μmol 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 in modelling leaf temperature to predict unfavourable growing conditions in a (dynamic) semi closed greenhouse.

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

    PubMed

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

    2009-09-01

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

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

    PubMed

    Dobránszki, Judit; Mendler-Drienyovszki, Nóra

    2014-10-15

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

  3. Ocean Primary Production Estimates from Terra MODIS and Their Dependency on Satellite Chlorophyll Alpha Algorithms

    NASA Technical Reports Server (NTRS)

    Essias, Wayne E.; Abbott, Mark; Carder, Kendall; Campbell, Janet; Clark, Dennis; Evans, Robert; Brown, Otis; Kearns, Ed; Kilpatrick, Kay; Balch, W.

    2003-01-01

    Simplistic models relating global satellite ocean color, temperature, and light to ocean net primary production (ONPP) are sensitive to the accuracy and limitations of the satellite estimate of chlorophyll and other input fields, as well as the primary productivity model. The standard MODIS ONPP product uses the new semi-analytic chlorophyll algorithm as its input for two ONPP indexes. The three primary MODIS chlorophyll Q estimates from MODIS, as well as the SeaWiFS 4 chlorophyll product, were used to assess global and regional performance in estimating ONPP for the full mission, but concentrating on 2001. The two standard ONPP algorithms were examined with 8-day and 39 kilometer resolution to quantify chlorophyll algorithm dependency of ONPP. Ancillary data (MLD from FNMOC, MODIS SSTD1, and PAR from the GSFC DAO) were identical. The standard MODIS ONPP estimates for annual production in 2001 was 59 and 58 GT C for the two ONPP algorithms. Differences in ONPP using alternate chlorophylls were on the order of 10% for global annual ONPP, but ranged to 100% regionally. On all scales the differences in ONPP were smaller between MODIS and SeaWiFS than between ONPP models, or among chlorophyll algorithms within MODIS. Largest regional ONPP differences were found in the Southern Ocean (SO). In the SO, application of the semi-analytic chlorophyll resulted in not only a magnitude difference in ONPP (2x), but also a temporal shift in the time of maximum production compared to empirical algorithms when summed over standard oceanic areas. The resulting increase in global ONPP (6-7 GT) is supported by better performance of the semi-analytic chlorophyll in the SO and other high chlorophyll regions. The differences are significant in terms of understanding regional differences and dynamics of ocean carbon transformations.

  4. Ocean Primary Production Estimates from Terra MODIS and Their Dependency on Satellite Chlorophyll Alpha Algorithms

    NASA Technical Reports Server (NTRS)

    Essias, Wayne E.; Abbott, Mark; Carder, Kendall; Campbell, Janet; Clark, Dennis; Evans, Robert; Brown, Otis; Kearns, Ed; Kilpatrick, Kay; Balch, W.

    2003-01-01

    Simplistic models relating global satellite ocean color, temperature, and light to ocean net primary production (ONPP) are sensitive to the accuracy and limitations of the satellite estimate of chlorophyll and other input fields, as well as the primary productivity model. The standard MODIS ONPP product uses the new semi-analytic chlorophyll algorithm as its input for two ONPP indexes. The three primary MODIS chlorophyll Q estimates from MODIS, as well as the SeaWiFS 4 chlorophyll product, were used to assess global and regional performance in estimating ONPP for the full mission, but concentrating on 2001. The two standard ONPP algorithms were examined with 8-day and 39 kilometer resolution to quantify chlorophyll algorithm dependency of ONPP. Ancillary data (MLD from FNMOC, MODIS SSTD1, and PAR from the GSFC DAO) were identical. The standard MODIS ONPP estimates for annual production in 2001 was 59 and 58 GT C for the two ONPP algorithms. Differences in ONPP using alternate chlorophylls were on the order of 10% for global annual ONPP, but ranged to 100% regionally. On all scales the differences in ONPP were smaller between MODIS and SeaWiFS than between ONPP models, or among chlorophyll algorithms within MODIS. Largest regional ONPP differences were found in the Southern Ocean (SO). In the SO, application of the semi-analytic chlorophyll resulted in not only a magnitude difference in ONPP (2x), but also a temporal shift in the time of maximum production compared to empirical algorithms when summed over standard oceanic areas. The resulting increase in global ONPP (6-7 GT) is supported by better performance of the semi-analytic chlorophyll in the SO and other high chlorophyll regions. The differences are significant in terms of understanding regional differences and dynamics of ocean carbon transformations.

  5. An investigation into robust spectral indices for leaf chlorophyll estimation

    NASA Astrophysics Data System (ADS)

    Main, Russell; Cho, Moses Azong; Mathieu, Renaud; O'Kennedy, Martha M.; Ramoelo, Abel; Koch, Susan

    2011-11-01

    Quantifying photosynthetic activity at the regional scale can provide important information to resource managers, planners and global ecosystem modelling efforts. With increasing availability of both hyperspectral and narrow band multispectral remote sensing data, new users are faced with a plethora of options when choosing an optical index to relate to their chosen or canopy parameter. The literature base regarding optical indices (particularly chlorophyll indices) is wide ranging and extensive, however it is without much consensus regarding robust indices. The wider spectral community could benefit from studies that apply a variety of published indices to differing sets of species data. The consistency and robustness of 73 published chlorophyll spectral indices have been assessed, using leaf level hyperspectral data collected from three crop species and a variety of savanna tree species. Linear regression between total leaf chlorophyll content and bootstrapping were used to determine the leafpredictive capabilities of the various indices. The indices were then ranked based on the prediction error (the average root mean square error (RMSE)) derived from the bootstrapping process involving 1000 iterative resampling with replacement. The results show two red-edge derivative based indices (red-edge position via linear extrapolation index and the modified red-edge inflection point index) as the most consistent and robust, and that the majority of the top performing indices (in spite of species variability) were simple ratio or normalised difference indices that are based on off-chlorophyll absorption centre wavebands (690-730 nm).

  6. Quantitative genetic analysis of chlorophyll a fluorescence parameters in maize in the field environments.

    PubMed

    Šimić, Domagoj; Lepeduš, Hrvoje; Jurković, Vlatka; Antunović, Jasenka; Cesar, Vera

    2014-07-01

    Chlorophyll fluorescence transient from initial to maximum fluorescence ("P" step) throughout two intermediate steps ("J" and "I") (JIP-test) is considered a reliable early quantitative indicator of stress in plants. The JIP-test is particularly useful for crop plants when applied in variable field environments. The aim of the present study was to conduct a quantitative trait loci (QTL) analysis for nine JIP-test parameters in maize during flowering in four field environments differing in weather conditions. QTL analysis and identification of putative candidate genes might help to explain the genetic relationship between photosynthesis and different field scenarios in maize plants. The JIP-test parameters were analyzed in the intermated B73 × Mo17 (IBM) maize population of 205 recombinant inbred lines. A set of 2,178 molecular markers across the whole maize genome was used for QTL analysis revealing 10 significant QTLs for seven JIP-test parameters, of which five were co-localized when combined over the four environments indicating polygenic inheritance and pleiotropy. Our results demonstrate that QTL analysis of chlorophyll fluorescence parameters was capable of detecting one pleiotropic locus on chromosome 7, coinciding with the gene gst23 that may be associated with efficient photosynthesis under different field scenarios. © 2014 Institute of Botany, Chinese Academy of Sciences.

  7. Sensitive Detection of Phosphorus Deficiency in Plants Using Chlorophyll a Fluorescence.

    PubMed

    Frydenvang, Jens; van Maarschalkerweerd, Marie; Carstensen, Andreas; Mundus, Simon; Schmidt, Sidsel Birkelund; Pedas, Pai Rosager; Laursen, Kristian Holst; Schjoerring, Jan K; Husted, Søren

    2015-09-01

    Phosphorus (P) is a finite natural resource and an essential plant macronutrient with major impact on crop productivity and global food security. Here, we demonstrate that time-resolved chlorophyll a fluorescence is a unique tool to monitor bioactive P in plants and can be used to detect latent P deficiency. When plants suffer from P deficiency, the shape of the time-dependent fluorescence transients is altered distinctively, as the so-called I step gradually straightens and eventually disappears. This effect is shown to be fully reversible, as P resupply leads to a rapid restoration of the I step. The fading I step suggests that the electron transport at photosystem I (PSI) is affected in P-deficient plants. This is corroborated by the observation that differences at the I step in chlorophyll a fluorescence transients from healthy and P-deficient plants can be completely eliminated through prior reduction of PSI by far-red illumination. Moreover, it is observed that the barley (Hordeum vulgare) mutant Viridis-zb(63), which is devoid of PSI activity, similarly does not display the I step. Among the essential plant nutrients, the effect of P deficiency is shown to be specific and sufficiently sensitive to enable rapid in situ determination of latent P deficiency across different plant species, thereby providing a unique tool for timely remediation of P deficiency in agriculture.

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

    PubMed

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

    2015-01-01

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

  9. Laser Induced Chlorophyll Fluorescence Spectra of Cajanus Cajan L Plant Growing Under Cadmium Stress

    NASA Astrophysics Data System (ADS)

    Gopal, Ram; Pandey, J. K.

    2010-06-01

    Laser-induced Chlorophyll fluorescence (LICF) spectra of Cajanus cajan L leaves treated with different concentrations of Cd (0.05, 0.5 and 1 mM) are recorded at 10 and 20 days after first treatment of cadmium. LICF spectra are recorded in the region of 650-780 nm using violet diode laser (405 nm). LICF spectra of plant leaves show two maxima near 685 and 730nm. Fluorescence induction kinetics (FIK) curve are recorded at 685 and 730 nm with red diode laser (635 nm) for excitation. The fluorescence intensity ratios (FIR) F685/F730 are calculated from LICF spectra and vitality index (Rfd) are determined from FIK curve. FIR and Rfd value are good stress indicator of plant health. These parameters along with chlorophyll content are used to analyze the effect of Cd on wheat plants. The result indicates that higher concentrations of Cd hazardous for photosynthetic activity and health of Arhar plants. The lower concentration of 0.05 mM shows stimulatory response up to 10 days while after 20 days this concentration also shows inhibitory response. R. Gopal, K. B. Mishra, M. Zeeshan, S. M. Prasad, and M. M. Joshi Curr. Sci., 83, 880, 2002 K. B. Mishra and R. Gopal Int. J. Rem. Sen., 29, 157, 2008 R. Maurya, S. M. Prasad, and R. Gopal J. Photochem. Photobio. C: Photochem. Rev., 9, 29, 2008

  10. Sensitive Detection of Phosphorus Deficiency in Plants Using Chlorophyll a Fluorescence1

    PubMed Central

    Frydenvang, Jens; van Maarschalkerweerd, Marie; Carstensen, Andreas; Mundus, Simon; Schmidt, Sidsel Birkelund; Pedas, Pai Rosager; Laursen, Kristian Holst; Schjoerring, Jan K.; Husted, Søren

    2015-01-01

    Phosphorus (P) is a finite natural resource and an essential plant macronutrient with major impact on crop productivity and global food security. Here, we demonstrate that time-resolved chlorophyll a fluorescence is a unique tool to monitor bioactive P in plants and can be used to detect latent P deficiency. When plants suffer from P deficiency, the shape of the time-dependent fluorescence transients is altered distinctively, as the so-called I step gradually straightens and eventually disappears. This effect is shown to be fully reversible, as P resupply leads to a rapid restoration of the I step. The fading I step suggests that the electron transport at photosystem I (PSI) is affected in P-deficient plants. This is corroborated by the observation that differences at the I step in chlorophyll a fluorescence transients from healthy and P-deficient plants can be completely eliminated through prior reduction of PSI by far-red illumination. Moreover, it is observed that the barley (Hordeum vulgare) mutant Viridis-zb63, which is devoid of PSI activity, similarly does not display the I step. Among the essential plant nutrients, the effect of P deficiency is shown to be specific and sufficiently sensitive to enable rapid in situ determination of latent P deficiency across different plant species, thereby providing a unique tool for timely remediation of P deficiency in agriculture. PMID:26162430

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

    PubMed

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

    2016-08-01

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

  12. Photosynthesis, chlorophyll fluorescence and spectral reflectance in Sphagnum moss at varying water contents.

    PubMed

    Van Gaalen, K Eric; Flanagan, Lawrence B; Peddle, Derek R

    2007-08-01

    Moss samples from the Fluxnet-Canada western peatland flux station in the Boreal Region of Alberta were measured in the laboratory to obtain the net photosynthesis rate and chlorophyll fluorescence of the moss under controlled environmental conditions, including the regulation of moss water content, simultaneously with measurements of moss spectral reflectance. One objective was to test whether the photochemical reflectance index (PRI) detected changes in moss photosynthetic light-use efficiency that were consistent with short-term (minutes to hours) changes in xanthophyll cycle pigments and associated changes in non-photochemical quenching (NPQ), as recorded by chlorophyll fluorescence. The rate of net photosynthesis was strongly inhibited by water content at values exceeding approximately 9 (fresh weight/dry weight) and declined as the water content fell below values of approximately 8. Chlorophyll fluorescence measurements of maximum photosystem II efficiency generally remained high until the water content was reduced from the maximum of about 20 to values of approximately 10-11, and then declined with further reductions in moss water content. A significant linear decline in NPQ was observed as moss water content was reduced from maximum to low water content values. There was a strong negative correlation between changes in NPQ and PRI. These data suggest that PRI measurements are a good proxy for short-term shifts in photosynthetic activity in Sphagnum moss. A second objective was to test how accurately the water band index (WBI, ratio of reflectance at 900 and 970 nm) recorded changes in moss water content during controlled laboratory studies. Strong linear relationships occurred between changes in moss water content and the WBI, although the slopes of the linear relationships were significantly different among sample replicates. Therefore, WBI appeared to be a useful tool to determine sample-specific water content without destructive measurements.

  13. Fluorescence imaging and chlorophyll fluorescence to evaluate the role of EDU in UV-B protection in cucumber

    NASA Astrophysics Data System (ADS)

    Sandhu, Ravinder K.; Kim, Moon S.; Krizek, Donald T.; Middleton, Elizabeth M.

    1997-07-01

    A fluorescence imaging system and chlorophyll fluorescence emissions were used to evaluate whether EDU, N-[2-(2-oxo-1- imidazolidinyl) ethyl]-N'-phenylurea, provided protection against ultraviolet-B (UV-B) irradiation (290 - 320 nm) in cucumber (Cucumis sativus L.) leaves. Plants were grown in growth chambers illuminated for 14 h per day with 400 W high pressure sodium and metal halide lamps. Photosynthetically active radiation (PAR) for 1 hr at the beginning and end of each cycle was provided at 270 micrometers ol m-2 s-1 PAR; during the other 12 hr of the photoperiod, the plants received 840 micrometers ol m-2 s-1 PAR. Beginning on the twelfth day, the plants were exposed to UV-B radiation (0.2 & 18.0 kJ m-2d-1) for 2 days at 8 h per day centered in the photoperiod. Rapidly acquired (less than 1 s), high spatial resolution (less than 1 mm2) images were obtained for whole adaxial leaf surfaces using a fluorescence imaging system. The steady-state fluorescence images were acquired in four spectral regions: blue (F450 nm), green (F550 nm), red (F680 nm), and far-red (F740 nm). Fluorescence emission spectra for leaf pigments extracted in dimethyl sulfoxide (DMSO) were obtained by excitation at 280 and 380 nm (280EX 300 - 530 nm; 380EX 400 - 800 nm). Both UV-B and EDU induced stress responses in cucumber leaves that altered the fluorescence emissions obtained from extracts. In the fluorescence images only UV-B induced stress responses were observed but this damage was detected before it was visually apparent. There was no evidence that EDU afforded protection against UV-B irradiation. Use of fluorescence imaging may provide an early stress detection capability for helping to assess damage to the photosynthetic apparatus of plants.

  14. Analysis of Sun-Induced Chlorophyll Fluorescence and Biophysical Variable Patterns in a Mixed Forest

    NASA Astrophysics Data System (ADS)

    Tagliabue, Giulia; Panigada, Cinzia; Baret, Frederic; Cogliati, Sergio; Colombo, Roberto; Guanter, Luis; Pinto, Francisco; Rascher, Uwe; Schickling, Anke; Van der Tol, Christiaan; Zarco-Tejada, Pablo; Rossini, Micol

    2016-08-01

    This work aims to analyse far-red Sun-induced chlorophyll fluorescence (F760) and vegetation optical properties in a forest ecosystem (Forêt de Hardt, FR) using ground measurements and airborne data acquired with the novel high-resolution imaging spectrometer HyPlant. The validated forest species map and F760 map obtained from HyPlant images were used to analyse F across a range of species. Results showed that different species are characterised by different F emission and that F can provide additional information in green and dense canopies where vegetation indices tend to saturate.

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

    PubMed

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

    2012-01-01

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

  16. Optimal Reflectance, Transmittance, and Absorptance Wavebands and Band Ratios for the Estimation of Leaf Chlorophyll Concentration

    NASA Technical Reports Server (NTRS)

    Carter, Gregory A.; Spiering, Bruce A.

    2000-01-01

    The present study utilized regression analysis to identify: wavebands and band ratios within the 400-850 nm range that could be used to estimate total chlorophyll concentration with minimal error; and simple regression models that were most effective in estimating chlorophyll concentrations were measured for two broadleaved species, a broadleaved vine, a needle-leaved conifer, and a representative of the grass family.Overall, reflectance, transmittance, and absorptance corresponded most precisely with chlorophyll concentration at wavelengths near 700 nm, although regressions were strong as well in the 550-625 nm range.

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

    PubMed

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

    2016-07-01

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

  18. A Dioxobilin-Type Fluorescent Chlorophyll Catabolite as a Transient Early Intermediate of the Dioxobilin-Branch of Chlorophyll Breakdown in Arabidopsis thaliana.

    PubMed

    Süssenbacher, Iris; Hörtensteiner, Stefan; Kräutler, Bernhard

    2015-11-09

    Chlorophyll breakdown in higher plants occurs by the so called "PaO/phyllobilin" path. It generates two major types of phyllobilins, the characteristic 1-formyl-19-oxobilins and the more recently discovered 1,19-dioxobilins. The hypothetical branching point at which the original 1-formyl-19-oxobilins are transformed into 1,19-dioxobilins is still elusive. Here, we clarify this hypothetical crucial transition on the basis of the identification of the first natural 1,19-dioxobilin-type fluorescent chlorophyll catabolite (DFCC). This transient chlorophyll breakdown intermediate was isolated from leaf extracts of Arabidopsis thaliana at an early stage of senescence. The fleetingly existent DFCC was then shown to represent the direct precursor of the major nonfluorescent 1,19-dioxobilin that accumulated in fully senescent leaves.

  19. Changes in foliar spectral reflectance and chlorophyll fluorescence of four temperate species following branch cutting.

    PubMed

    Richardson, Andrew D; Berlyn, Graeme P

    2002-05-01

    Spectral reflectance and chlorophyll fluorescence are rapid non-invasive methods that can be used to quantify plant stress. Because variation in ambient light (e.g., diurnal patterns of solar radiation) may have a confounding effect on these measurements, branches are often excised in the field and then measured under controlled conditions in the laboratory. We studied four temperate tree species (Abies balsamea (L.) Mill. (balsam fir), Betula papyrifera var. cordifolia (Regel) Fern. (paper birch), Picea rubens Sarg. (red spruce) and Sorbus americana Marsh. (mountain-ash)) to determine how quickly reflectance and fluorescence change following branch cutting. We hypothesized that conifer species, which have tough xeromorphic foliage, would exhibit changes more slowly than broadleaf species. Furthermore, we hypothesized that keeping broadleaf samples cool and moist would delay the onset of reflectance and fluorescence changes. In one set of experiments, we did not use any treatments to maintain the freshness of cut branches. During the first 12 h following cutting, changes in reflectance and fluorescence were slight for all species. Two or 3 days after branch cutting, the two conifers still showed only small changes in the ratio of variable to maximum fluorescence (Fv/Fm) and most reflectance indices, whereas paper birch and mountain-ash showed larger and more rapid declines in Fv/Fm and most reflectance indices. We attribute these declines to loss of water. As a consequence of xeromorphic leaf structure, the conifers were better able to minimize water loss than the two broadleaf species. In another experiment, paper birch that had been kept cool and moist after cutting showed only slight changes in fluorescence and reflectance, even after 3 days, indicating that with careful handling the time interval between collection and measurement of reflectance and fluorescence of many broadleaf specimens can be extended to several days. We conclude that measurements of

  20. Chlorophyll Concentration Estimates for Coastal Waters using Pixel-Based Atmospheric Correction of Landsat Images

    NASA Astrophysics Data System (ADS)

    Kouba, E.; Xie, H.

    2014-12-01

    Ocean color analysis is more challenging for coastal regions than the global ocean due the effects of optical brightness, shallow and turbid water, higher phytoplankton growth rates, and the complex geometry of coastal bays and estuaries. Also, one of the key atmospheric correction assumptions (zero water leaving radiance in the near infrared) is not valid for these complex conditions. This makes it difficult to estimate the spectral radiance noise caused by atmospheric aerosols, which can vary rapidly with time and space. This project evaluated using Landsat-7 ETM+ observations over a set of coastal bays, and allowing atmospheric correction calculations to vary with time and location as much as practical. Precise satellite orbit vector data was combined with operational weather and climate data to create interpolated arrays of atmospheric profiles which varied with time and location, allowing separate calculation of the Rayleigh and aerosol radiance corrections for all pixels. The resulting normalized water-leaving radiance values were compared with chlorophyll fluorescence measurements made at five in-situ stations inside a set of Texas coastal bays: the Mission-Aransas National Estuarine Research Reserve. Curve-fitting analysis showed it was possible to estimate chlorophyll surface area concentrations by using ETM+ water-leaving radiance values and a third-order polynomial equation. Two pairs of ETM+ bands were identified as inputs (Bands 1 and 3, and the Log10 values of Bands 3 and 4), both achieving R2 of 0.69. Additional research efforts were recommended to obtain additional data, identify better curve fitting equations, and potentially extend the radiative transfer model into the water column.

  1. Chlorophyll concentration estimates for coastal water using pixel-based atmospheric correction of Landsat images

    NASA Astrophysics Data System (ADS)

    Kouba, Eric

    Ocean color analysis is more challenging for coastal regions than the global ocean due the effects of optical brightness, shallow and turbid water, higher phytoplankton growth rates, and the complex geometry of coastal bays and estuaries. Also, one of the key atmospheric correction assumptions (zero water leaving radiance in the near infrared) is not valid for these complex conditions. This makes it difficult to estimate the spectral radiance noise caused by atmospheric aerosols, which can vary rapidly with time and space. This study conducts pixel-based atmospheric correction of Landsat-7 ETM+ images over the Texas coast. Precise satellite orbit data, operational weather data, and climate data are combined to create interpolated arrays of viewing angles and atmospheric profiles. These arrays vary with time and location, allowing calculation of the Rayleigh and aerosol radiances separately for all pixels. The resulting normalized water-leaving radiances are then compared with in situ chlorophyll fluorescence measurements from five locations inside a set of Texas coastal bays: the Mission-Aransas National Estuarine Research Reserve. Curve-fitting analysis shows it is possible to estimate chlorophyll-a surface area concentrations by using ETM+ water-leaving radiance values and a third-order polynomial equation. Two pairs of ETM+ bands are identified as inputs (Bands 1 and 3, and the Log10 values of Bands 3 and 4), both achieving good performance (R2 of 0.69). Further research efforts are recommended to obtain additional data, identify better curve fitting equations, and potentially extend the radiative transfer model into the water column.

  2. Spermine and lutein quench chlorophyll fluorescence in isolated PSII antenna complexes.

    PubMed

    Malliarakis, Dimitris; Tsiavos, Theodoros; Ioannidis, Nikolaos E; Kotzabasis, Kiriakos

    2015-07-01

    Non photochemical quenching is a spontaneous mechanism that protects plants and algae from photodamage. In the last two decades, carotenoids through the xanthophylls cycle have been proposed to play a key role in quenching of chlorophyll. More recently, the involvement of endogenous polyamines in energy-dependent component of non photochemical quenching has been suggested by several research groups. In the present contribution, the combined effect of spermine and the xanthophylls, zeaxanthin and lutein on the fluorescence of antenna complexes of photosystem II was tested in vitro. Lutein caused significant quenching on trimeric and monomeric antenna complexes, whereas zeaxanthin under our experimental conditions had negligible effect. Spermine has been shown to allow fluorescence quenching to be induced in isolated antenna in the absence of ΔpH and to accelerate quenching formation. The simultaneous treatment of spermine and lutein maximizes quenching even at relatively low concentrations.

  3. Modified in situ antimicrobial susceptibility testing method based on cyanobacteria chlorophyll a fluorescence.

    PubMed

    Heliopoulos, Nikolaos S; Galeou, Angeliki; Papageorgiou, Sergios K; Favvas, Evangelos P; Katsaros, Fotios K; Stamatakis, Kostas

    2016-02-01

    The chlorophyll a fluorescence based antimicrobial susceptibility testing (AST) method presented in a previous work was based on the measurement of Chl a fluorescence of the gram(-) cyanobacterium Synechococcus sp. PCC 7942. Synechococcus sp. PCC 7942 as a gram(-) bacterium is affected by antibacterial agents via mechanisms affecting all gram(-) bacteria, however, as an exclusively phototrophic organism it would also be affected by photosynthesis inhibitory action of an agent that otherwise has no antibacterial properties. In this report, the method is modified by replacing the exclusively phototrophic Synechococcus sp. PCC 7942 with the Synechocystis sp. PCC 6714, capable of both phototrophic and heterotrophic growth in order to add versatility and better reflect the antibacterial effects of surfaces under study towards nonphotosynthetic bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Chlorophyll a fluorescence in evaluation of the effect of heavy metal soil contamination on perennial grasses.

    PubMed

    Żurek, Grzegorz; Rybka, Krystyna; Pogrzeba, Marta; Krzyżak, Jacek; Prokopiuk, Kamil

    2014-01-01

    Chlorophyll a fluorescence gives information about the plant physiological status due to its coupling to the photosynthetic electron transfer chain and to the further biochemical processes. Environmental stresses, which acts synergistically, disturbs the photosynthesis. The OJIP test, elaborated by Strasser and co-workers, enables comparison of the physiological status of plants grown on polluted vs. control areas. The paper shows that the Chl a measurements are very useful tool in evaluating of heavy metal ions influence on perennial grasses, tested as potential phytoremediators. Among 5 cultivars tested, the highest concentration of Cd and Zn ions, not associated with the yield reduction, was detected in the biomass of tall fescue cv. Rahela. Chl a fluorescence interpreted as double normalized curves pointed out Rahela as the outstanding cultivar under the HM ions stress.

  5. Chlorophyll a Fluorescence in Evaluation of the Effect of Heavy Metal Soil Contamination on Perennial Grasses

    PubMed Central

    Żurek, Grzegorz; Rybka, Krystyna; Pogrzeba, Marta; Krzyżak, Jacek; Prokopiuk, Kamil

    2014-01-01

    Chlorophyll a fluorescence gives information about the plant physiological status due to its coupling to the photosynthetic electron transfer chain and to the further biochemical processes. Environmental stresses, which acts synergistically, disturbs the photosynthesis. The OJIP test, elaborated by Strasser and co-workers, enables comparison of the physiological status of plants grown on polluted vs. control areas. The paper shows that the Chl a measurements are very useful tool in evaluating of heavy metal ions influence on perennial grasses, tested as potential phytoremediators. Among 5 cultivars tested, the highest concentration of Cd and Zn ions, not associated with the yield reduction, was detected in the biomass of tall fescue cv. Rahela. Chl a fluorescence interpreted as double normalized curves pointed out Rahela as the outstanding cultivar under the HM ions stress. PMID:24633293

  6. Topography of Photosynthetic Activity of Leaves Obtained from Video Images of Chlorophyll Fluorescence 1

    PubMed Central

    Daley, Paul F.; Raschke, Klaus; Ball, J. Timothy; Berry, Joseph A.

    1989-01-01

    The distribution of photosynthetic activity over the area of a leaf and its change with time was determined (at low partial pressure of O2) by recording images of chlorophyll fluorescence during saturating light flashes. Simultaneously, the gas exchange was being measured. Reductions of local fluorescence intensity quantitatively displayed the extent of nonphotochemical quenching; quench coefficients, qN, were computed pixel by pixel. Because rates of photosynthetic electron transport are positively correlated with (1 − qN), computed images of (1 − qN) represented topographies of photosynthetic activity. Following application of abscisic acid to the heterobaric leaves of Xanthium strumarium L., clearly delineated regions varying in nonphotochemical quenching appeared that coincided with areoles formed by minor veins and indicated stomatal closure in groups. Images Figure 2 Figure 4 Figure 6 PMID:16666912

  7. Chlorophyll fluorescence as a bioindicator of effects on growth in aquatic macrophytes from mixtures of polycyclic aromatic hydrocarbons.

    PubMed

    Marwood, C A; Solomon, K R; Greenberg, B M

    2001-04-01

    Chlorophyll-a fluorescence induction is a rapid technique for measuring photosynthetic electron transport in plants. To assess chlorophyll-a fluorescence as a bioindicator of effects of polycyclic aromatic hydrocarbon mixtures, chlorophyll-a fluorescence parameters and plant growth responses to exposure to the wood preservative creosote were examined in the aquatic plants Lemna gibba and Myriophyllum spicatum. Exposure to creosote inhibited growth of L. gibba (EC50 = 7.2 mg/L total polycyclic aromatic hydrocarbons) and M. spicatum (EC50 = 2.6 mg/L) despite differences in physiology. Creosote also diminished maximum PSII efficiency (Fv/Fm) (EC50 = 36 and 13 mg/L for L. gibba and M. spicatum) and the effective yield of photosystem II photochemistry (deltaF/Fm') (EC50 = 13 and 15 mg/L for L. gibba and M. spicatum). The similarity between growth and chlorophyll-a fluorescence EC50s and slopes of the response curves suggests a close mechanistic link between these end points. The predictive power of chlorophyll-a fluorescence as a bioindicator of whole-organism effects applied to complex contaminant mixtures is discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  9. A procedure for maize genotypes discrimination to drought by chlorophyll fluorescence imaging rapid light curves.

    PubMed

    de Sousa, Carlos Antônio Ferreira; de Paiva, Dayane Silva; Casari, Raphael Augusto das Chagas Noqueli; de Oliveira, Nelson Geraldo; Molinari, Hugo Bruno Correa; Kobayashi, Adilson Kenji; Magalhães, Paulo Cesar; Gomide, Reinaldo Lúcio; Souza, Manoel Teixeira

    2017-01-01

    Photosynthesis can be roughly separated into biochemical and photochemical processes. Both are affected by drought and can be assessed by non-invasive standard methods. Gas exchange, which mainly assesses the first process, has well-defined protocols. It is considered a standard method for evaluation of plant responses to drought. Under such stress, assessment of photochemical apparatus by chlorophyll fluorescence needs improvement to become faster and reproducible, especially in growing plants under field conditions. For this, we developed a protocol based on chlorophyll fluorescence imaging, using a rapid light curve approach. Almost all parameters obtained by rapid light curves have shown statistical differences between control and drought stressed maize plants. However, most of them were affected by induction processes, relaxation rate, and/or differences in chlorophyll content; while they all were influenced by actinic light intensity on each light step of light curve. Only the normalized parameters related to photochemical and non-photochemical quenching were strongly correlated with data obtained by gas exchange, but only from the light step in which the linear electron flow reached saturation. The procedure developed in this study for discrimination of plant responses to water deficit stress proved to be as fast, efficient and reliable as the standard technique of gas exchange in order to discriminate the responses of maize genotypes to drought. However, unlike that, there is no need to perform daily and time consuming calibration routines. Moreover, plant acclimation to the dark is not required. The protocol can be applied to plants growing in both controlled conditions and full sunlight in the field. In addition, it generates parameters in a fast and accurate measurement process, which enables evaluating several plants in a short period of time.

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

    NASA Astrophysics Data System (ADS)

    Van Wittenberghe, Shari

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

  11. Effects of fosmidomycin on plant photosynthesis as measured by gas exchange and chlorophyll fluorescence.

    PubMed

    Possell, Malcolm; Ryan, Annette; Vickers, Claudia E; Mullineaux, Philip M; Hewitt, C Nicholas

    2010-04-01

    In higher plants, many isoprenoids are synthesised via the chloroplastic 1-deoxy-D-xylulose 5-phosphate/2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Attempts to elucidate the function of individual isoprenoids have used the antibiotic/herbicidal compound fosmidomycin (3-[N-formyl-N-hydroxy amino] propyl phosphonic acid) to inhibit this pathway. Examination of the effect of fosmidomycin on the major components of photosynthesis in leaves of white poplar (Populus alba) and tobacco (Nicotiana tabacum) was made. Fosmidomycin reduced net photosynthesis in both species within 1 h of application, but only when photosynthesis was light-saturated. In P. alba, these reductions were confounded by high light and fosmidomycin inducing stomatal patchiness. In tobacco, this was caused by significant reductions in PSII chlorophyll fluorescence and reductions in V(cmax) and J(max). Our data indicate that the diminution of photosynthesis is likely a complex effect resulting from the inhibition of multiple MEP pathway products, resulting in photoinhibition and photo-damage. These effects should be accounted for in experimental design and analysis when using fosmidomycin to avoid misinterpretation of results as measured by gas exchange and chlorophyll fluorescence.

  12. Image Analysis of Chlorophyll Fluorescence Transients for Diagnosing the Photosynthetic System of Attached Leaves

    PubMed Central

    Omasa, Kenji; Shimazaki, Ken-Ichiro; Aiga, Ichiro; Larcher, Walter; Onoe, Morio

    1987-01-01

    A new image instrumentation system for quantitative analysis of the rapid change in intensity of chlorophyll fluorescence during dark-light transition (CFI, chlorophyll fluorescence induction), which is a sensitive indicator of the various reactions of photosynthesis, was developed and its performance was evaluated. This system made it possible to resolve CFI at any small leaf area (about 1 square millimeter) of a whole leaf when the plant was illuminated by blue-green light at more than 50 micromoles photons per square meter per second. In order to test the usefulness of this system, we applied it to analyze the effect of SO2 on photosynthetic apparatus in attached sunflower leaves. Dynamic CFI imaging over the whole single leaf, where there was no visible injury, indicated not only the local changes in photosynthetic activity but also the site of inhibition in photosynthetic electron transport system in chloroplasts. The new instrumentation system will be useful for the analytical diagnosis of various stress-actions on plants in situ. Images Fig. 1 Fig. 5 Fig. 6 PMID:16665515

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

    NASA Astrophysics Data System (ADS)

    Sun, G.; Wang, X.; Niu, Zh; Chen, F.

    2014-02-01

    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.

  14. [Fluorescence peak shift corresponding to high chlorophyll concentrations in inland water].

    PubMed

    Duan, Hong-Tao; Ma, Rong-Hua; Zhang, Yuan-Zhi; Zhang, Bai

    2009-01-01

    Hyperspectral remote sensing offers the potential to detect water quality variables such as Chl-a by using narrow spectral channels of less than 10 nm, which could otherwise be masked by broadband satellites such as Landsat TM. Fluorescence peak of the red region is very important for the remote sensing of inland and coastal waters, which is unique to phytoplankton Chl-a that takes place in this region. Based on in situ water sampling and field spectral measurement from 2004 to 2006 in Nanhu Lake, the features of the spectral reflectance were analyzed in detail with peak position shift. The results showed: An exponential fitting model, peak position = a(Chl-a)b, was developed between chlorophyll-a concentration and fluorescence peak shift, where a varies between 686.11 and 686.29, while b between 0.0062 and 0.0065. It was found that the better the spectral resolution, the higher the precision of the model. Except that, the average of peak shift showed a high correlation with the average of different Chl-a grades, and the determination coefficient (R2) was higher than 0.81. It contributed significantly to the increase in the accuracy of the derivation of chlorophyll values from remote sensing data in Nanhu Lake. There is satisfactory correspondence between hyperspectral models and chl-a concentration, therefore, it is possible to monitor the water quality of Nanhu lake throngh the hyperspetral remote sensing data.

  15. Interactions between iron and titanium metabolism in spinach: a chlorophyll fluorescence study in hydropony.

    PubMed

    Cigler, Petr; Olejnickova, Julie; Hruby, Martin; Csefalvay, Ladislav; Peterka, Jiri; Kuzel, Stanislav

    2010-12-15

    One of the elements showing strong beneficial effect on plants at low concentrations and toxic effects at higher concentrations is titanium (Ti). We investigated the interconnection between the Fe uptake and the Ti intoxication in model experiment on Fe-deficient spinach (Spinacia oleracea) plants to help to elucidate the mechanism of the biological activity of titanium in plants. The two different Ti (0 and 20 mg L⁻¹) and two different Fe (0 and 1.35 mg L⁻¹) concentrations in hydroponic medium were used in all four possible combinations. We compared chemical analysis of Ti and Fe in roots and shoots with the changes of the in vivo chlorophyll fluorescence. Although Fe and Ti concentration found in shoots of Ti-non-treated Fe-deficient plants was comparable with that in Ti-treated Fe-deficient plants, the soluble form of Ti present in the growth media had a negative effect on photosynthetic activity monitored by chlorophyll fluorescence measurements. The presence of Fe in growth medium significantly decreased the Ti concentration in shoots and increased the photosynthetic activity. Here, we propose that Ti affect components of electron transport chain containing Fe in their structure (particularly photosystem I) and decrease the photosystem II efficiency.

  16. Detection of Photosynthetic Performance of Stipa bungeana Seedlings under Climatic Change using Chlorophyll Fluorescence Imaging

    PubMed Central

    Song, Xiliang; Zhou, Guangsheng; Xu, Zhenzhu; Lv, Xiaomin; Wang, Yuhui

    2016-01-01

    In this study, the impact of future climate change on photosynthetic efficiency as well as energy partitioning in the Stipa bungeana was investigated by using chlorophyll fluorescence imaging (CFI) technique. Two thermal regimes (room temperature, T0: 23.0/17.0°C; High temperature, T6: 29.0/23.0°C) and three water conditions (Control, W0; Water deficit, W−30; excess precipitation, W+30) were set up in artificial control chambers. The results showed that excess precipitation had no significant effect on chlorophyll fluorescence parameters, while water deficit decreased the maximal quantum yield of photosystem II (PSII) photochemistry for the dark-adapted state (Fv/Fm) by 16.7%, with no large change in maximal quantum yield of PSII photochemistry for the light-adapted state (FV′/FM′) and coefficient of the photochemical quenching (qP) at T0 condition. Under T6 condition, high temperature offset the negative effect of water deficit on Fv/Fm and enhanced the positive effect of excess precipitation on Fv/Fm, Fv′/Fm′, and qP, the values of which all increased. This indicates that the temperature higher by 6°C will be beneficial to the photosynthetic performance of S. bungeana. Spatial changes of photosynthetic performance were monitored in three areas of interest (AOIs) located on the bottom, middle and upper position of leaf. Chlorophyll fluorescence images (Fv/Fm, actual quantum yield of PSII photochemistry for the light-adapted state (ΦPSII), quantum yield of non-regulated energy dissipation for the light-adapted state (ΦNO) at T0 condition, and ΦPSII at T6 condition) showed a large spatial variation, with greater value of ΦNO and lower values of Fv/Fm and ΦPSII in the upper position of leaves. Moreover, there was a closer relationship between ΦPSII and ΦNO, suggesting that the energy dissipation by non-regulated quenching mechanisms played a dominant role in the yield of PSII photochemistry. It was also found that, among all measured fluorescence

  17. Detection of Photosynthetic Performance of Stipa bungeana Seedlings under Climatic Change using Chlorophyll Fluorescence Imaging.

    PubMed

    Song, Xiliang; Zhou, Guangsheng; Xu, Zhenzhu; Lv, Xiaomin; Wang, Yuhui

    2015-01-01

    In this study, the impact of future climate change on photosynthetic efficiency as well as energy partitioning in the Stipa bungeana was investigated by using chlorophyll fluorescence imaging (CFI) technique. Two thermal regimes (room temperature, T0: 23.0/17.0°C; High temperature, T6: 29.0/23.0°C) and three water conditions (Control, W0; Water deficit, W-30; excess precipitation, W+30) were set up in artificial control chambers. The results showed that excess precipitation had no significant effect on chlorophyll fluorescence parameters, while water deficit decreased the maximal quantum yield of photosystem II (PSII) photochemistry for the dark-adapted state (F v/F m) by 16.7%, with no large change in maximal quantum yield of PSII photochemistry for the light-adapted state (F V'/F M') and coefficient of the photochemical quenching (q P ) at T0 condition. Under T6 condition, high temperature offset the negative effect of water deficit on F v/F m and enhanced the positive effect of excess precipitation on F v/F m, F v'/F m', and q P , the values of which all increased. This indicates that the temperature higher by 6°C will be beneficial to the photosynthetic performance of S. bungeana. Spatial changes of photosynthetic performance were monitored in three areas of interest (AOIs) located on the bottom, middle and upper position of leaf. Chlorophyll fluorescence images (F v/F m, actual quantum yield of PSII photochemistry for the light-adapted state (ΦPSII), quantum yield of non-regulated energy dissipation for the light-adapted state (ΦNO) at T0 condition, and ΦPSII at T6 condition) showed a large spatial variation, with greater value of ΦNO and lower values of F v/F m and ΦPSII in the upper position of leaves. Moreover, there was a closer relationship between ΦPSII and ΦNO, suggesting that the energy dissipation by non-regulated quenching mechanisms played a dominant role in the yield of PSII photochemistry. It was also found that, among all measured

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

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    Kristoffersen, Arne S; Hamre, Børge; Frette, Øyvind; Erga, Svein R

    2016-04-01

    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 laser scanning microscope. The lifetimes were measured in the time domain by time-correlated single-photon counting. Under normal conditions, the fluorescence lifetime was 262 ps, while after 2 h of exposure to UV radiation the lifetime increased to 389 ps, indicating decreased photochemical quenching, likely caused by a damaged and down-regulated photosynthetic apparatus. This was supported by a similar increase in the lifetime to 425 ps when inhibiting photosynthesis chemically using DCMU. Furthermore, the UV-stressed sample was dark-adapted overnight, resulting in a return of the lifetime to 280 ps, revealing that the damage caused by UV radiation is repairable on a relatively short time scale. This reversal of photosynthetic activity was also confirmed by [Formula: see text] measurements.

  1. [Fluorescence parameters of chlorophyll in leaves of caules plants in different environmental conditions].

    PubMed

    Iakovleva, O V; Talipova, E V; Kukarskikh, G P; Krendeleeva, T E; Rubin, A B

    2005-01-01

    The functional state of medicinal plants of Convallaria majalis L., Vaccinium vitis-idaeae L., Arctostaphylos uva-ursi L. in connection with heavy metal accumulation in their leaves under man impact was studied by the pulse-amplitude-modulation (PAM) fluorometric method. The relative yield of variable fluorescence (F(v)/F(m)), induction of fluorescence of chlorophyll, and fluorescence quenching processes in leaves at different distances from the local Kirov-Sovetsk, Kirov-Omutninsk road in Kirov region were analyzed. Changes in biophysical characteristics with the increasing content of heavy metals in leaves were demonstrated. The most informative characteristic is F(v)/F(m). Its value correlates with the activity of the photosynthetic apparatus and reflects the potential effeciency of photosynthesis. The better are the environmental conditions of plant growth, the higher is the F(v)/F(m) ratio and the lower is its average statistical deviation. Fluorescence induction curves do not always vary in shape under our ecological conditions, indicating relatively favorable conditions at places of plant growth investigated. The rate of the environmental pollution in the investigated region is not critical, since the content of heavy metal in leaves does not change considerably with the distance from the road.

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

    USGS Publications Warehouse

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

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

  4. Inferred influence of nutrient availability on the relationship between Sun-induced chlorophyll fluorescence and incident irradiance in the Bering Sea

    NASA Astrophysics Data System (ADS)

    Schallenberg, Christina; Lewis, Marlon R.; Kelley, Dan E.; Cullen, John J.

    2008-07-01

    This study examines variability in the relationship between Sun-induced chlorophyll fluorescence and incident solar irradiance as a potential diagnostic of the nutritional status of phytoplankton. The study site is the Bering Sea, where two optical drifters were caught for more than 100 days in an anticyclonic eddy, while two others provided data from adjacent waters. Estimates of fluorescence emission normalized to the absorption of light by pigments were analyzed as a function of irradiance to describe variability of the quantum yield of fluorescence. Yields in bright sunlight and under lower light varied by a factor of 5 or more on the scale of days to weeks. For the one drifter that remained in the high-velocity region of the eddy, there was a lagged correlation between the eddy rotation period and fluorescence parameters, with higher fluorescence yields in both low and high irradiance associated with slower rotation. Since nutrient input to the photic zone may increase with increasing shear of the eddy flow, this is consistent with the established suggestion that Sun-induced fluorescence increases with nutrient stress in phytoplankton. Independent measurements of variable fluorescence (Fv/Fm, an indicator of photosynthetic efficiency) further support this interpretation. However, modeling shows that the established hypothesis of competition between photosynthesis and fluorescence for absorbed photons (i.e., photochemical quenching), with high fluorescence yields reflecting photosynthetic debility, does not apply near the sea surface, where photosynthesis is saturated, and dissipation of excess absorbed radiation by nonphotochemical quenching is the dominant influence on fluorescence yield.

  5. Vegetation chlorophyll estimates in the Amazon from multi-angle MODIS observations and canopy reflectance model

    NASA Astrophysics Data System (ADS)

    Hilker, Thomas; Galvão, Lênio Soares; Aragão, Luiz E. O. C.; de Moura, Yhasmin M.; do Amaral, Cibele H.; Lyapustin, Alexei I.; Wu, Jin; Albert, Loren P.; Ferreira, Marciel José; Anderson, Liana O.; dos Santos, Victor A. H. F.; Prohaska, Neill; Tribuzy, Edgard; Barbosa Ceron, João Vitor; Saleska, Scott R.; Wang, Yujie; de Carvalho Gonçalves, José Francisco; de Oliveira Junior, Raimundo Cosme; Cardoso Rodrigues, João Victor Figueiredo; Garcia, Maquelle Neves

    2017-06-01

    As a preparatory study for future hyperspectral missions that can measure canopy chemistry, we introduce a novel approach to investigate whether multi-angle Moderate Resolution Imaging Spectroradiometer (MODIS) data can be used to generate a preliminary database with long-term estimates of chlorophyll. MODIS monthly chlorophyll estimates between 2000 and 2015, derived from a fully coupled canopy reflectance model (ProSAIL), were inspected for consistency with eddy covariance fluxes, tower-based hyperspectral images and chlorophyll measurements. MODIS chlorophyll estimates from the inverse model showed strong seasonal variations across two flux-tower sites in central and eastern Amazon. Marked increases in chlorophyll concentrations were observed during the early dry season. Remotely sensed chlorophyll concentrations were correlated to field measurements (r2 = 0.73 and r2 = 0.98) but the data deviated from the 1:1 line with root mean square errors (RMSE) ranging from 0.355 μg cm-2 (Tapajós tower) to 0.470 μg cm-2 (Manaus tower). The chlorophyll estimates were consistent with flux tower measurements of photosynthetically active radiation (PAR) and net ecosystem productivity (NEP). We also applied ProSAIL to mono-angle hyperspectral observations from a camera installed on a tower to scale modeled chlorophyll pigments to MODIS observations (r2 = 0.73). Chlorophyll pigment concentrations (ChlA+B) were correlated to changes in the amount of young and mature leaf area per month (0.59 ≤ r2 ≤ 0.64). Increases in MODIS observed ChlA+B were preceded by increased PAR during the dry season (0.61 ≤ r2 ≤ 0.62) and followed by changes in net carbon uptake. We conclude that, at these two sites, changes in LAI, coupled with changes in leaf chlorophyll, are comparable with seasonality of plant productivity. Our results allowed the preliminary development of a 15-year time series of chlorophyll estimates over the Amazon to support canopy chemistry studies using future

  6. Automated observation of diurnal solar-induced chlorophyll fluorescence for better understanding of crop photosynthesis

    NASA Astrophysics Data System (ADS)

    Huang, C.; Zhang, L.; Wang, S.; Qiao, N.

    2016-12-01

    Remotely sensed solar-induced chlorophyll fluorescence (SIF) has been considered an ideal probe in monitoring vegetation photosynthesis. However, numerous challenges have greatly limited its wide applications, including accurate estimate of faint SIF from the observed apparent reflected radiation, uncertainties in inferring the vegetation photosynthesis as well as lack of validation. These difficulties should be resolved at ground-based controlled scales before the launch of SIF satellite platforms such as ESA's FLEX (to be launched 2021). Currently, increasing continuous and long-term automated SIF measurement systems have been reported for better understanding the diurnal and seasonal changes of vegetation photosynthesis. This study introduces a newly developed automated SIF field measurement system (Auto-SIF, 500-800 nm, FWHM=0.74 nm, SSI=0.38 nm, SNR=1000:1, see figure 1) in China and its initial results for inferring photosynthesis of different crops including soybean (three types), maize (two types) and rice (two types). The experiments were conducted at the test crop field affiliated to the Institute of Genetics and Development Biology, Chinese Academy of Sciences. The Auto-SIF incorporates two observation modes, i.e., reference panel mode and target mode (see figure 1), and the two modes can be switched very quickly through an electrical motor. All diurnal super-spectra data and SIFs of crops were collected in clear days and with a finer time interval of 1minute, therefore they can be easily resampled to different time intervals (see figure 2) in order for convenient comparisons with other data from different observation platforms, like 30-minute tower-flux GPP data. For better understanding of crop photosynthesis, Li-6400 XT (LI-COR, Inc.) and TES-1339R light meter were respectively used in this study to simultaneously obtain diurnal dynamics of leaf-level SIFs and sun incoming flux. Due to the availability of wide spectral range of Auto-SIF (500-800 nm

  7. Quantifying spatial heterogeneity of chlorophyll fluorescence during plant growth and in response to water stress.

    PubMed

    Bresson, Justine; Vasseur, François; Dauzat, Myriam; Koch, Garance; Granier, Christine; Vile, Denis

    2015-01-01

    Effects of abiotic and biotic stresses on plant photosynthetic performance lead to fitness and yield decrease. The maximum quantum efficiency of photosystem II (F v/F m) is a parameter of chlorophyll fluorescence (ChlF) classically used to track changes in photosynthetic performance. Despite recent technical and methodological advances in ChlF imaging, the spatio-temporal heterogeneity of F v/F m still awaits for standardized and accurate quantification. We developed a method to quantify the dynamics of spatial heterogeneity of photosynthetic efficiency through the distribution-based analysis of F v/F m values. The method was applied to Arabidopsis thaliana grown under well-watered and severe water deficit (survival rate of 40%). First, whole-plant F v/F m shifted from unimodal to bimodal distributions during plant development despite a constant mean F v/F m under well-watered conditions. The establishment of a bimodal distribution of F v/F m reflects the occurrence of two types of leaf regions with contrasted photosynthetic efficiency. The distance between the two modes (called S) quantified the whole-plant photosynthetic heterogeneity. The weighted contribution of the most efficient/healthiest leaf regions to whole-plant performance (called W max) quantified the spatial efficiency of a photosynthetically heterogeneous plant. Plant survival to water deficit was associated to high S values, as well as with strong and fast recovery of W max following soil rewatering. Hence, during stress surviving plants had higher, but more efficient photosynthetic heterogeneity compared to perishing plants. Importantly, S allowed the discrimination between surviving and perishing plants four days earlier than the mean F v/F m. A sensitivity analysis from simulated dynamics of F v/F m showed that parameters indicative of plant tolerance and/or stress intensity caused identifiable changes in S and W max. Finally, an independent comparison of six Arabidopsis accessions grown under

  8. [Estimation of chlorophyll content in apple tree canopy based on hyperspectral parameters].

    PubMed

    Pan, Bei; Zhao, Geng-Xing; Zhu, Xi-Cun; Liu, Hai-Teng; Liang, Shuang; Tian, Da-De

    2013-08-01

    The hyperspectral reflectance of apple tree canopy during spring shoots stopping growth period was measured using ASD FieldSpec3 field spectrometer. Original spectral data were processed in deviation forms, and significant spectrum parameters correlated with chlorophyll content were found out with correlation analysis. The best vegetation indices were chosen and the apple canopy chlorophyll content estimation model was established by analyzing vegetation index of two-band combination in the sensitive region 400-1 350 nm. The result showed that (1) The sensitive band region of apple canopy chlorophyll content is 400-1 350 nm. (2) The vegetation index CCI(D(794)/D(763)) can commendably estimate the apple canopy chlorophyll content. (3) The model with CCI(D(794)/D(763)) as the independent variables was determined to be the best for chlorophyll content prediction of apple tree canopy. Therefore, using hyperspectral technology can estimate apple canopy chlorophyll content more rapidly and accurately, and provides a theoretical basis for rapid apple tree canopy nutrition diagnosis and growth monitoring.

  9. Fluorescence and absorption spectroscopy of the weakly fluorescent chlorophyll a in cytochrome b6f of Synechocystis PCC6803.

    PubMed Central

    Peterman, E J; Wenk, S O; Pullerits, T; Pâlsson, L O; van Grondelle, R; Dekker, J P; Rögner, M; van Amerongen, H

    1998-01-01

    A spectroscopic characterization of the chlorophyll a (Chl) molecule in the monomeric cytochrome b6f complex (Cytb6f) isolated from the cyanobacterium Synechocystis PCC6803 is presented. The fluorescence lifetime and quantum yield have been determined, and it is shown that Chl in Cytb6f has an excited-state lifetime that is 20 times smaller than that of Chl in methanol. This shortening of the Chl excited state lifetime is not caused by an increased rate of intersystem crossing. Most probably it is due to quenching by a nearby amino acid. It is suggested that this quenching is a mechanism for preventing the formation of Chl triplets, which can lead to the formation of harmful singlet oxygen. Using site-selected fluorescence spectroscopy, detailed information on vibrational frequencies in both the ground and Qy excited states has been obtained. The vibrational frequencies indicate that the Chl molecule has one axial ligand bound to its central magnesium and accepts a hydrogen bond to its 13(1)-keto carbonyl. The results show that the Chl binds to a well-defined pocket of the protein and experiences several close contacts with nearby amino acids. From the site-selected fluorescence spectra, it is further concluded that the electron-phonon coupling is moderately strong. Simulations of both the site-selected fluorescence spectra and the temperature dependence of absorption and fluorescence spectra are presented. These simulations indicate that the Huang-Rhys factor characterizing the electron-phonon coupling strength is between 0.6 and 0.9. The width of the Gaussian inhomogeneous distribution function is 210 +/- 10 cm-1. PMID:9649396

  10. Global simulation of canopy scale sun-induced chlorophyll fluorescence with a 3 dimensional radiative transfer model

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Yang, W.; Ichii, K.

    2015-12-01

    Global simulation of canopy scale sun-induced chlorophyll fluorescence with a 3 dimensional radiative transfer modelHideki Kobayashi, Wei Yang, and Kazuhito IchiiDepartment of Environmental Geochemical Cycle Research, Japan Agency for Marine-Earth Science and Technology3173-25, Showa-machi, Kanazawa-ku, Yokohama, Japan.Plant canopy scale sun-induced chlorophyll fluorescence (SIF) can be observed from satellites, such as Greenhouse gases Observation Satellite (GOSAT), Orbiting Carbon Observatory-2 (OCO-2), and Global Ozone Monitoring Experiment-2 (GOME-2), using Fraunhofer lines in the near infrared spectral domain [1]. SIF is used to infer photosynthetic capacity of plant canopy [2]. However, it is not well understoond how the leaf-level SIF emission contributes to the top of canopy directional SIF because SIFs observed by the satellites use the near infrared spectral domain where the multiple scatterings among leaves are not negligible. It is necessary to quantify the fraction of emission for each satellite observation angle. Absorbed photosynthetically active radiation of sunlit leaves are 100 times higher than that of shaded leaves. Thus, contribution of sunlit and shaded leaves to canopy scale directional SIF emission should also be quantified. Here, we show the results of global simulation of SIF using a 3 dimensional radiative transfer simulation with MODIS atmospheric (aerosol optical thickness) and land (land cover and leaf area index) products and a forest landscape data sets prepared for each land cover category. The results are compared with satellite-based SIF (e.g. GOME-2) and the gross primary production empirically estimated by FLUXNET and remote sensing data.

  11. Neural network-based estimation of chlorophyll-a concentration in coastal waters

    NASA Astrophysics Data System (ADS)

    Musavi, Mohamad T.; Miller, Richard L.; Ressom, Habtom; Natarajan, Padma

    2002-01-01

    The estimation of chlorophyll-a is one of the key indices of monitoring the phytoplankton populations. In this paper, an approach for estimating chlorophyll-a concentration using a neural network model is prose. A dat set assembled form various sources during the SeaWiFS Bio-optical Algorithm Mini-Workshop containing coincident in-situ chlorophyll and remote sensing reflectance measurements is used to evaluate the efficacy of the proposed neural network model. The data comprises of 919 stations and has chlorophyll-a concentrations ranging between 0.019 and 32.79 (mu) g/l. There are approximately 20 observations form more turbid coastal waters. A feed-forward neural network model with 10 noes in the hidden layer has been constructed to estimate chlorophyll-a concentration. The remote sensing reflectances form five SeaWiFS wavelengths are used as inputs to our model. The network is trained using the Levenberg-Marquardt algorithm. A neural network model can deal with non-linear relationships more accurately. Neural networks can effectively include variables that tend to co-vary non- linearly relationships more accurately. Neural networks can effectively include variables that tend to co-vary non- linearly with the output variable. They are flexible towards the choice of inputs and are tolerant to noise and require no a priori knowledge about the effect of these parameters. This makes them an ideal candidate for estimating chlorophyll-a concentration in coastal waters, where the presence of suspended sediments, detritus, and dissolved organic matter creates an optically complex situation. By allowing the neural network model to include several optical parameters as additional inputs to account for the scattering and absorption phenomena the model can be extended to estimate chlorophyll-a concentration turbid coastal waters.

  12. Design of chlorophyll-a and turbidity sensor based on fluorescence induction and scattering-light detection

    NASA Astrophysics Data System (ADS)

    Zhang, Keke; Liu, Shixuan; Chen, Shizhe; Qi, Yong; Miao, Bin; Yan, Xingkui; Bai, Xuejiao

    2014-07-01

    The chlorophyll-a and turbidity sensor based on the principles of fluorescence induction and scattering-light detection is designed. Using fluorescence induction technology, scattering-light detection technology and weak signal detection technology, chlorophyll-a concentration measurement and turbidity measurement in seawater are integrated in a set of testing equipment to implement software and hardware reuse and improve the integration of the device, which has the features of small size and easy operation. The comparative experiments and repetitive experiments are completed with ALEC ACLW-CAR chlorophyll / turbidity sensor. Experiment results show that chlorophyll-a concentration, turbidity and the system output values have good linear relationships, and the fitting coefficients are 0.999. Repeatability standard deviations of chlorophyll-a detection and turbidity detection are better than 0.08 μg/L and 0.04 FTU, respectively, and the accuracy of the device within +/- 2%. Chlorophyll-a and turbidity in-situ monitoring in seawater can be achieved using this testing equipment.

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

    PubMed

    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.

  14. Changes in chlorophyll a fluorescence of glyphosate-tolerant soybean plants induced by glyphosate: in vivo analysis by laser-induced fluorescence spectroscopy.

    PubMed

    Fernandes, Joelson; Falco, William Ferreira; Oliveira, Samuel Leite; Caires, Anderson Rodrigues Lima

    2013-05-01

    A significant increase in the use of the herbicide glyphosate has generated many questions about its residual accumulation in the environment and possible damage to crops. In this study, changes in chlorophyll a (chl-a) fluorescence induced by glyphosate in three varieties of glyphosate-resistant soybean plants were determined with an in vivo analysis based on a portable laser-induced fluorescence system. Strong suppression of chl-a fluorescence was observed for all plants treated with the herbicide. Moreover, the ratio of the emission bands in the red and far-red regions (685 nm/735 nm) indicates that the application of glyphosate led to chlorophyll degradation. The results also indicated that the use of glyphosate, even at concentrations recommended by the manufacturer, suppressed chl-a fluorescence. In summary, this study shows that fluorescence spectroscopy can detect, in vivo, very early changes in the photosynthetic status of transgenic soybeans treated with this herbicide.

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

    PubMed

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

    2006-10-01

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

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

    PubMed

    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.

  17. A simple chlorophyll fluorescence parameter that correlates with the rate coefficient of photoinactivation of photosystem II.

    PubMed

    Hendrickson, Luke; Förster, Britta; Pogson, Barry J; Chow, Wah Soon

    2005-06-01

    A method of partitioning the energy in a mixed population of active and photoinactivated Photosystem II (PS II) complexes based on chlorophyll fluorescence measurements is presented. There are four energy fluxes, each with its quantum efficiency: a flux associated with photochemical electron flow in active PS II reaction centres (JPS II), thermal dissipation in photoinactivated, non-functional PS IIs (JNF), light-regulated thermal dissipation in active PS IIs (JNPQ) and a combined flux of fluorescence and constitutive, light-independent thermal dissipation (Jf,D). The four quantum efficiencies add up to 1.0, without the need to introduce an 'excess' term E, which in other studies has been claimed to be linearly correlated with the rate coefficient of photoinactivation of PS II (kpi). We examined the correlation of kpi with various fluxes, and found that the combined flux (JNPQ + Jf,D= Jpi) is as well correlated with kpi as is E. This combined flux arises from Fs/Fm ', the ratio of steady-state to maximum fluorescence during illumination, which represents the quantum efficiency of combined non-photochemical dissipation pathways in active PS IIs. Since Fs/Fm ' or its equivalent, Jpi, is a likely source of events leading to photoinactivation of PS II, we conclude that Fs/Fm ' is a simple predictor of kpi.

  18. Chloroplast Ultrastructure, Chlorophyll Fluorescence, and Pigment Composition in Chilling-Stressed Soybeans 1

    PubMed Central

    Musser, Robert L.; Thomas, Shirley A.; Wise, Robert R.; Peeler, Thomas C.; Naylor, Aubrey W.

    1984-01-01

    Shoots of 16-day-old soybeans (Glycine max L. Merr. cv Ransom) were chilled to 10°C for 7 days and monitored for visible signs of damage, ultrastructural changes, perturbations in fluorescence of chlorophyll (Chl), and quantitative changes in Chl a and b and associated pigments. Precautions were taken to prevent the confounding effects of water stress. A technique for the separation of lutein and zeaxanthin was developed utilizing a step gradient with the high performance liquid chromatograph. Visible losses in Chl were detectable within the first day of chilling, and regreening did not occur until the shoots were returned to 25°C. Ultrastructurally, unstacking of chloroplast grana occurred, and the envelope membranes developed protrusions. Furthermore, the lipids were altered to the point that the membranes were poorly stabilized by a glutaraldehyde/osmium double-fixation procedure. Chl fluorescence rates were greatly reduced within 2 hours after chilling began and returned to normal only after rewarming. The rapid loss of Chl that occurred during chilling was accompanied by the appearance of zeaxanthin and a decline in violaxanthin. Apparently a zeaxanthin-violaxanthin epoxidation/de-epoxidation cycle was operating. When only the roots were chilled, no substantial changes were detected in ultrastructure, fluorescence rates, or pigment levels. Images Fig. 1 Fig. 2 Fig. 3 PMID:16663504

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

    PubMed

    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.

  20. Effects of ozone fumigation on epiphytic macrolichens: ultrastructure, CO2 gas exchange and chlorophyll fluorescence.

    PubMed

    Scheidegger, C; Schroeter, B

    1995-01-01

    The lichen species Anaptychia ciliaris, Collema nigrescens, Evernia prunastri, Hypogymnia bitteri, Lobaria pulmonaria, Pseudevernia furfuracea and Usnea rigida s.l. were fumigated with site-relevant concentrations (for Central Europe) of ozone over 80 days (180 microg m(-3) during daytime, 80 microg m(-3) during the night). Chlorophyll fluorescence measurements revealed a significant reduction of Fv/Fm after ozone fumigation in five of the species investigated, indicating severe stress on photosystem II due to ozone. The physiological impairment paralleled our fine structural investigations, revealing a significantly higher percentage of collapsed photobiont cells. This indicates that the effects of ambient ozone concentrations under experimental conditions included biophysical and physiological, as well as structural impairment in the lichens studied.

  1. Does sun-induced Chlorophyll fluorescence well capture canopy photosynthesis in a rice paddy?

    NASA Astrophysics Data System (ADS)

    Kimm, H.; Ryu, Y.; Kang, M.; Kim, J.

    2015-12-01

    Sun-induced chlorophyll fluorescence (SiF) has emerged as a convincing indicator of carbon assimilation rates under diverse environmental conditions. Here, we present a continuous observation system of SiF at a sporadically irrigated rice paddy site in South Korea. Our site also includes automatic observation systems for eddy covariance, water table depth, and spectral sensors which are composed of LED sensors, and RGB- and NIR cameras. Additionally, we conducted manual observations of photosynthetic parameters (Li-6400), leaf area index (LAI-2200), NDVI and PRI (ASD FieldSpec) once per ten days on average. By analyzing manual- and automatic field observations, we quantify carbon budget of the site. Finally, we investigate how accurately SiF detects canopy photosynthesis, and discuss what factors mainly control canopy photosynthesis.

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

    PubMed

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

    2014-10-01

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

  3. An in situ antimicrobial susceptibility testing method based on in vivo measurements of chlorophyll α fluorescence.

    PubMed

    Heliopoulos, Nikolaos S; Galeou, Angeliki; Papageorgiou, Sergios K; Favvas, Evangelos P; Katsaros, Fotios K; Stamatakis, Kostas

    2015-05-01

    Up to now antimicrobial susceptibility testing (AST) methods are indirect and generally involve the manual counting of bacterial colonies following the extraction of microorganisms from the surface under study and their inoculation in a separate procedure. In this work, an in situ, direct and instrumental method for the evaluation and assessment of antibacterial properties of materials and surfaces is proposed. Instead of indirectly determining antibacterial activity using the typical gram(-) test organisms with the subsequent manual colony count or inhibition zone measurement, the proposed procedure, employs photosynthetic gram(-) cyanobacteria deposited directly onto the surface under study and assesses cell proliferation and viability by a quick, accurate and reproducible instrumental chlorophyll fluorescence spectrophotometric technique. In contrast with existing methods of determination of antibacterial properties, it produces high resolution and quantitative results and is so versatile that it could be used to evaluate the antibacterial properties of any compound (organic, inorganic, natural or man-made) under any experimental conditions, depending on the targeted application.

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

    PubMed

    Dreuw, Andreas; Wormit, Michael

    2008-03-01

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

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

    PubMed

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

    2017-03-01

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

  6. Linking chlorophyll a fluorescence to photosynthesis for remote sensing applications: mechanisms and challenges.

    PubMed

    Porcar-Castell, Albert; Tyystjärvi, Esa; Atherton, Jon; van der Tol, Christiaan; Flexas, Jaume; Pfündel, Erhard E; Moreno, Jose; Frankenberg, Christian; Berry, Joseph A

    2014-08-01

    Chlorophyll a fluorescence (ChlF) has been used for decades to study the organization, functioning, and physiology of photosynthesis at the leaf and subcellular levels. ChlF is now measurable from remote sensing platforms. This provides a new optical means to track photosynthesis and gross primary productivity of terrestrial ecosystems. Importantly, the spatiotemporal and methodological context of the new applications is dramatically different compared with most of the available ChlF literature, which raises a number of important considerations. Although we have a good mechanistic understanding of the processes that control the ChlF signal over the short term, the seasonal link between ChlF and photosynthesis remains obscure. Additionally, while the current understanding of in vivo ChlF is based on pulse amplitude-modulated (PAM) measurements, remote sensing applications are based on the measurement of the passive solar-induced chlorophyll fluorescence (SIF), which entails important differences and new challenges that remain to be solved. In this review we introduce and revisit the physical, physiological, and methodological factors that control the leaf-level ChlF signal in the context of the new remote sensing applications. Specifically, we present the basis of photosynthetic acclimation and its optical signals, we introduce the physical and physiological basis of ChlF from the molecular to the leaf level and beyond, and we introduce and compare PAM and SIF methodology. Finally, we evaluate and identify the challenges that still remain to be answered in order to consolidate our mechanistic understanding of the remotely sensed SIF signal.

  7. Compost may affect volatile and semi-volatile plant emissions through nitrogen supply and chlorophyll fluorescence.

    PubMed

    Ormeño, Elena; Olivier, Romain; Mévy, Jean Philippe; Baldy, Virginie; Fernandez, Catherine

    2009-09-01

    The use of composted biosolids as an amendment for forest regeneration in degraded ecosystems is growing since sewage-sludge dumping has been banned in the European Community. Its consequences on plant terpenes are however unknown. Terpene emissions of both Rosmarinus officinalis (a terpene-storing species) and Quercus coccifera (a non-storing species) and terpene content of the former, were studied after a middle-term exposure to compost at intermediate (50tha(-1): D50) and high (100tha(-1): D100) compost rates, in a seven-year-old post-fire shrubland ecosystem. Some chlorophyll fluorescence parameters (Fv/Fm, ETR, Phi(PSII)), soil and plant enrichment in phosphorus (P) and nitrogen (N) were monitored simultaneously in amended and non-amended plots in order to establish what factors were responsible for possible compost effect on terpenes. Compost affected all studied parameters with the exception of Fv/Fm and terpene content. For both species, mono- and sesquiterpene basal emissions were intensified solely under D50 plots. On the contrary leaf P, leaf N levels reached in D50 were partly responsible of terpene changes, suggesting that optimal N conditions occurred therein. N also affected ETR and Phi(PSII) which were, in turn, robustly correlated to terpene emissions. These results imply that emissions of terpene-storing and non-storing species were under nitrogen and chlorophyll fluorescence control, and that a correct management of compost rates applied on soil may modify terpene emission rate of plants, which in turn has consequences in air quality and plant defense mechanisms.

  8. Laser-induced chlorophyll fluorescence: a technique for detection of dimethoate effect on chlorophyll content and photosynthetic activity of wheat plant.

    PubMed

    Pandey, Jitendra Kumar; Gopal, R

    2011-03-01

    Laser-induced chlorophyll fluorescence (LICF) spectra and fluorescence induction kinetics (FIK) curves of wheat plant leaves treated with different concentrations (50, 100 and 200 ppm) of dimethoate are recorded. LICF spectra are recorded in the region of 650-780 nm using violet diode laser (405 nm) and FIK curve at 685 and 730 nm with red diode laser (635 nm) for excitation. The fluorescence intensity ratios (FIR) are determined from LICF spectra and vitality index (R(fd)) from FIK curves. These parameters along with photosynthetic pigment contents and growth parameters are used to analyze the effect of dimethoate on wheat plants. The result indicates that lower concentration of 50 ppm shows stimulatory response while higher concentrations of dimethoate are hazardous for growth, photosynthetic pigments and activity of wheat plants.

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

    PubMed

    Sharma, Dew Kumari; Fernández, Juan Olivares; Rosenqvist, Eva; Ottosen, Carl-Otto; Andersen, Sven Bode

    2014-05-01

    The genotypic response of wheat cultivars as affected by two methods of heat stress treatment (treatment of intact plants in growth chambers versus treatment of detached leaves in test tubes) in a temperature controlled water bath were compared to investigate how such different methods of heat treatment affect chlorophyll fluorescence parameters. A set of 41 spring wheat cultivars differing in their maximum photochemical efficiency of photosystem (PS) II (Fv/Fm) under heat stress conditions was used. These cultivars were previously evaluated based on the heat treatment of intact plants. The 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 the fluorescence parameters. In contrast, heat induced reduction in the maximum photochemical efficiency of PSII of detached leaves occurred within 2h at 40°C and within 30min at 45°C, and the response was more pronounced than when intact plants were heat stressed for three days at 40°C. The proportion of total variation that can be ascribed to the genetic differences among cultivars for a trait was estimated as genetic determination. During heat treatment, the genetic determination of most of the fluorescence parameters was lower in detached leaves than in intact plants. In addition, the correlation of the cultivar response in intact plants versus detached leaves was low (r=0.13 (with expt.1) and 0.02 with expt.2). The most important difference between the two methods was the pronounced difference in time scale of reaction, which may indicate the involvement of different physiological mechanisms in response to high temperatures. Further, the results suggest that genetic factors associated with cultivar differences are different for the two methods of heat treatment

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2004-10-01

    The chlorophyll fluorescence was studied in Petiveria alliacea plants exposed to different nitrogen concentrations and light radiation, the response was measured by two different forms; (1) measuring the photosynthetic efficiency with a pulse amplitude modulated fluorometro (PAM) emitted by a 650 nm diode and (2) measuring the fluorescence spectra caused by high power 452 nm diode with a SD2000 spectrometer. It was found out that the photosynthetic efficiency decreased in the plants exposed to high radiance and low nitrogen. Two chlorophyll fluorescence peaks were observed on 684 nm and 739 nm, the intensities in this wavelengths are inversely related with the light radiance. The correlation between the FIR and photosynthetic efficiency was very strong (r2 = -0.809, p <<0.01) this let us conclude that the fluorescence spectral analysis induced by the diode (excitation at 452 nm) is an efficient technique to detect stress by high light intensity and nitrogen in P. Alliacea plants.

  12. Chemical bonding of chlorophylls and plant aminic axial ligands impact harvesting of visible light and quenching of fluorescence.

    PubMed

    Ioannidis, Nikolaos E; Tsiavos, Theodoros; Kotzabasis, Kiriakos

    2012-01-01

    In the present work, we tested the mode of interaction of all three polyamines (putrescine, spermidine and spermine) with chlorophyll a and b, as well as pheophytin a and b. The results showed that all three polyamines bind to the Mg ion of chlorophyll ring as probed by Raman spectroscopy. The coordination of spermine with Chl b has the most interesting features from all pigments tested. Spermine induces reversible increases and decreases of the fluorescence yield of Chl b at about 661 nm. Interestingly, equilibrium between a high-fluorescence yield conformation and a low yield is feasible by the interaction of chlorophyll b and aminic ligands. Furthermore, absorption data for the diagnostic regions of 518 and 535 nm are provided for all combinations of pigments and ligands. The significance and consistence of these results with respect to photochemical and bioenergetic principles are discussed.

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

    PubMed

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

    2014-08-01

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

  14. A statistical algorithm for estimating chlorophyll concentration from MODIS data

    NASA Astrophysics Data System (ADS)

    Wattelez, Guillaume; Dupouy, Cécile; Mangeas, Morgan; Lèfevre, Jérôme; Touraivane, T.; Frouin, Robert J.

    2014-11-01

    We propose a statistical algorithm to assess chlorophyll-a concentration ([chl-a]) using remote sensing reflectance (Rrs) derived from MODerate Resolution Imaging Spectroradiometer (MODIS) data. This algorithm is a combination of two models: one for low [chl-a] (oligotrophic waters) and one for high [chl-a]. A satellite pixel is classified as low or high [chla] according to the Rrs ratio (488 and 555 nm channels). If a pixel is considered as a low [chl-a] pixel, a log-linear model is applied; otherwise, a more sophisticated model (Support Vector Machine) is applied. The log-linear model was developed thanks to supervised learning on Rrs and [chl-a] data from SeaBASS and more than 15 campaigns accomplished from 2002 to 2010 around New Caledonia. Several models to assess high [chl-a] were also tested with statistical methods. This novel approach outperforms the standard reflectance ratio approach. Compared with algorithms such as the current NASA OC3, Root Mean Square Error is 30% lower in New Caledonian waters.

  15. Remote chlorophyll fluorescence measurements with the laser-induced fluorescence transient approach.

    PubMed

    Pieruschka, Roland; Klimov, Denis; Berry, Joseph A; Osmond, C Barry; Rascher, Uwe; Kolber, Zbigniew S

    2012-01-01

    The interaction of plants with their environment is very dynamic. Studying the underlying processes is important for understanding and modeling plant response to changing environmental conditions. Photosynthesis varies largely between different plants and at different locations within a canopy of a single plant. Thus, continuous and spatially distributed monitoring is necessary to assess the dynamic response of photosynthesis to the environment. Limited scale of observation with portable instrumentation makes it difficult to examine large numbers of plants under different environmental conditions. We report here on the application of a recently developed technique, laser-induced fluorescence transient (LIFT), for continuous remote measurement of photosynthetic efficiency of selected leaves at a distance of up to 50 m. The ability to make continuous, automatic, and remote measurements of photosynthetic efficiency of leaves with the LIFT provides a new approach for studying the interaction of plants with the environment and may become an important tool in phenotyping photosynthetic properties in field applications.

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

    EPA Science Inventory

    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...

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

    EPA Science Inventory

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  19. Combined effects of phosphorus nutrition and elevated carbon dioxide concentration on chlorophyll fluorescence, photosynthesis, and nutrient efficiency of cotton

    USDA-ARS?s Scientific Manuscript database

    To examine the combined effects of phosphorus nutrition and CO2 on photosynthetic and chlorophyll fluorescence (CF) processes, and nutrient utilization and uptake, two controlled environment experiments were conducted using 0.20, 0.05 and 0.01 mM external phosphate (Pi) nutrition each at ambient and...

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

    NASA Astrophysics Data System (ADS)

    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.

  1. On the relation between the Kautsky effect (chlorophyll a fluorescence induction) and Photosystem II: basics and applications of the OJIP fluorescence transient.

    PubMed

    Stirbet, Alexandrina; Govindjee

    2011-01-01

    Chlorophyll a fluorescence is a highly sensitive, non-destructive, and reliable tool for measuring, rather quickly, photosynthetic efficiency, particularly of Photosystem II (PSII), the water-plastoquinone oxidoreductase. We briefly review here the connection between the fast (up to 2 s) chlorophyll fluorescence rise and PSII, as well as the empirical use of the fluorescence rise kinetics in understanding photosynthetic reactions, particularly of PSII. When dark-adapted photosynthetic samples are exposed to light, a fluorescence induction is observed, known as the Kautsky effect, after Hans Kautsky, the discoverer of the phenomenon showing the existence of variable fluorescence. The chlorophyll fluorescence intensity rises from a minimum level (the O level), in less than 1 s, to a maximum level (the P-level) via two intermediate steps labeled J and I. This is followed by a decline to a lower semi-steady state level, the S level, which is reached in about one minute. We provide here an educational review on how this phenomenon has been exploited through analysis of the fast OJIP fluorescence transient, by discussing basic assumptions, derivation of equations, as well as application to PSII-related questions. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Leaf Chlorophyll Content Estimation of Winter Wheat Based on Visible and Near-Infrared Sensors.

    PubMed

    Zhang, Jianfeng; Han, Wenting; Huang, Lvwen; Zhang, Zhiyong; Ma, Yimian; Hu, Yamin

    2016-03-25

    The leaf chlorophyll content is one of the most important factors for the growth of winter wheat. Visual and near-infrared sensors are a quick and non-destructive testing technology for the estimation of crop leaf chlorophyll content. In this paper, a new approach is developed for leaf chlorophyll content estimation of winter wheat based on visible and near-infrared sensors. First, the sliding window smoothing (SWS) was integrated with the multiplicative scatter correction (MSC) or the standard normal variable transformation (SNV) to preprocess the reflectance spectra images of wheat leaves. Then, a model for the relationship between the leaf relative chlorophyll content and the reflectance spectra was developed using the partial least squares (PLS) and the back propagation neural network. A total of 300 samples from areas surrounding Yangling, China, were used for the experimental studies. The samples of visible and near-infrared spectroscopy at the wavelength of 450,900 nm were preprocessed using SWS, MSC and SNV. The experimental results indicate that the preprocessing using SWS and SNV and then modeling using PLS can achieve the most accurate estimation, with the correlation coefficient at 0.8492 and the root mean square error at 1.7216. Thus, the proposed approach can be widely used for winter wheat chlorophyll content analysis.

  3. An Evaluation of an In Situ Fluorometer for the Estimation of Chlorophyll a

    DTIC Science & Technology

    1993-05-01

    acidification ) was measured on a Turner 111 fluorometer calibrated using pure chlorophyll a. Laboratory Calibration. For the phytoplankton culture, we used...Whitledge and Wirick, 1983; Weller et al., 1985; Marra et al. 1990) and in lakes (e.g., Heaney, 1978; Abbott et al., 1982). However, worries have...indicative of photoadaptation of the phytoplankton populations (Fig. 1). The data from OC3 are perhaps clearest in showing a pure fluorescence maximum

  4. MES16, a Member of the Methylesterase Protein Family, Specifically Demethylates Fluorescent Chlorophyll Catabolites during Chlorophyll Breakdown in Arabidopsis12[W][OA

    PubMed Central

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

    2012-01-01

    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 C132-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

  5. Stress-induced alteration of chlorophyll fluorescence polarization and spectrum in leaves of Alocasia macrorrhiza L. Schott.

    PubMed

    Lin, Zhi-Fang; Liu, Nan; Lin, Gui-Zhu; Pan, Xiao-Ping; Peng, Chang-Lian

    2007-11-01

    The value of intrinsic chlorophyll fluorescence polarization, and the intensity in emission spectrum were investigated in leaf segments of Alocasia macrorrhiza under several stress conditions including different temperatures (25-50 degrees C), various concentrations of NaCl (0-250 mM), methyl viologen (MV, 0-25 microM), SDS (0-1.0%) and NaHSO(3) (0-80 microM). Fluorescence emission spectrum of leaves at wavelength regions of 500-800 nm was monitored by excitation at 436 nm. The value of fluorescence polarization (P value), as result of energy transfer and mutual orientation between chlorophyll molecules, was determined by excitation at 436 nm and emission at 685 nm. The results showed that elevated temperature and concentrations of salt (NaCl), photooxidant (MV), surfactant (SDS) and simulated SO(2) (NaHSO(3)) treatments all induced a reduction of fluorescence polarization to various degrees. However, alteration of the fluorescence spectrum and emission intensity of F(685) and F(731) depended on the individual treatment. Increase in temperature and concentration of NaHSO(3) enhanced fluorescence intensity mainly at F(685), while an increase in MV concentration led to a decrease at both F(685) and F(731). On the contrary, NaCl and SDS did not cause remarkable change in fluorescence spectrum. Among different treatments, the negative correlation between polarization and fluorescence intensity was found with NaHSO(3) treatments only. We concluded that P value being measured with intrinsic chlorophyll fluorescence as probe in leaves is a susceptible indicator responding to changes in environmental conditions. The alteration of P value and fluorescence intensity might not always be shown a functional relation pattern. The possible reasons of differed response to various treatments were discussed.

  6. Effects of artemisinin on photosystem II performance of Microcystis aeruginosa by in vivo chlorophyll fluorescence.

    PubMed

    Ni, Lixiao; Acharya, Kumud; Hao, Xiangyang; Li, Shiyin; Li, Yong; Li, Yiping

    2012-12-01

    Effects of artemisinin (derived from Artemisia annua) on the photosynthetic activity of Microcystis aeruginosa was investigated by using chlorophyll a (Chl a) fluorescence transient O-J-I-P and JIP-test after exposure to elevated artemisinin concentration. High artemisinin concentration resulted in a significant suppression in photosynthesis and respiration. Results showed that the OJIP curves flattened and the maximal fluorescence yield reached at the J step under artemisinin stress. The decreased values of the energy needed for the RCs' closure (Sm) and the number of oxidation and reduction (N) suggested that the reduction times of primary bound plastoquinone (Q(A)) was also decreased. The absorption flux (ABS/RC) per photosystem II (PSII) reaction center and the electron transport flux (ET(0)/RC) decreased with increasing artemisinin concentration. Excess artemisinin had little effect on the trapping flux (TR(0)/RC). The results showed that the decrease of photosynthesis in exposure to excess artemisinin may be a result of the inactivation of PSII reaction centers and the inhibition of electron transport in the acceptor side.

  7. Relaxation of the non-photochemical chlorophyll fluorescence quenching in diatoms: kinetics, components and mechanisms

    PubMed Central

    Roháček, Karel; Bertrand, Martine; Moreau, Brigitte; Jacquette, Boris; Caplat, Christelle; Morant-Manceau, Annick; Schoefs, Benoît

    2014-01-01

    Diatoms are especially important microorganisms because they constitute the larger group of microalgae. To survive the constant variations of the light environment, diatoms have developed mechanisms aiming at the dissipation of excess energy, such as the xanthophyll cycle and the non-photochemical chlorophyll (Chl) fluorescence quenching. This contribution is dedicated to the relaxation of the latter process when the adverse conditions cease. An original nonlinear regression analysis of the relaxation of non-photochemical Chl fluorescence quenching, qN, in diatoms is presented. It was used to obtain experimental evidence for the existence of three time-resolved components in the diatom Phaeodactylum tricornutum: qNf, qNi and qNs. qNf (s time-scale) and qNs (h time-scale) are exponential in shape. By contrast, qNi (min time-scale) is of sigmoidal nature and is dominant among the three components. The application of metabolic inhibitors (dithiothreitol, ammonium chloride, cadmium and diphenyleneiodonium chloride) allowed the identification of the mechanisms on which each component mostly relies. qNi is linked to the relaxation of the ΔpH gradient and the reversal of the xanthophyll cycle. qNs quantifies the stage of photoinhibition caused by the high light exposure, qNf seems to reflect fast conformational changes within thylakoid membranes in the vicinity of the photosystem II complexes. PMID:24591721

  8. Pico-projector-based optical sectioning microscopy for 3D chlorophyll fluorescence imaging of mesophyll cells

    NASA Astrophysics Data System (ADS)

    Chen, Szu-Yu; Hsu, Yu John; Yeh, Chia-Hua; Chen, S.-Wei; Chung, Chien-Han

    2015-03-01

    A pico-projector-based optical sectioning microscope (POSM) was constructed using a pico-projector to generate structured illumination patterns. A net rate of 5.8 × 106 pixel/s and sub-micron spatial resolution in three-dimensions (3D) were achieved. Based on the pico-projector’s flexibility in pattern generation, the characteristics of POSM with different modulation periods and at different imaging depths were measured and discussed. With the application of different modulation periods, 3D chlorophyll fluorescence imaging of mesophyll cells was carried out in freshly plucked leaves of four species without sectioning or staining. For each leaf, an average penetration depth of 120 μm was achieved. Increasing the modulation period along with the increment of imaging depth, optical sectioning images can be obtained with a compromise between the axial resolution and signal-to-noise ratio. After ∼30 min imaging on the same area, photodamage was hardly observed. Taking the advantages of high speed and low damages of POSM, the investigation of the dynamic fluorescence responses to temperature changes was performed under three different treatment temperatures. The three embedded blue, green and red light-emitting diode light sources were applied to observe the responses of the leaves with different wavelength excitation.

  9. [Estimation and forecast of chlorophyll a concentration in Taihu Lake based on ensemble square root filters].

    PubMed

    Li, Yuan; Li, Yun-Mei; Wang, Qiao; Zhang, Zhuo; Guo, Fei; Lü, Heng; Bi, Kun; Huang, Chang-Chun; Guo, Yu-Long

    2013-01-01

    Chlorophyll a concentration is one of the important parameters for the characterization of water quality, which reflects the degree of eutrophication and algae content in the water body. It is also an important factor in determining water spectral reflectance. Chlorophyll a concentration is an important water quality parameter in water quality remote sensing. Remote sensing quantitative retrieval of chlorophyll a concentration can provide new ideas and methods for the monitoring and evaluation of lake water quality. In this work, we developed a data assimilation scheme based on ensemble square root filters and three-dimensional numerical modeling for wind-driven circulation and pollutant transport to assimilate the concentration of chlorophyll a. We also conducted some assimilation experiments using buoy observation data on May 20, 2010. We estimated the concentration of chlorophyll a in Taihu Lake, and then used this result to forecast the concentration of chlorophyll a. During the assimilation stage, the root mean square error reduced from 1.58, 1.025, and 2.76 to 0.465, 0.276, and 1.01, respectively, and the average relative error reduced from 0.2 to 0.05, 0.046, and 0.069, respectively. During the prediction stage, the root mean square error reduced from 1.486, 1.143, and 2.38 to 0.017, 0.147, and 0.23, respectively, and the average relative error reduced from 0.2 to 0.002, 0.025, and 0.019, respectively. The final results indicate that the method of data assimilation can significantly improve the accuracy in the estimation and prediction of chlorophyll a concentration in Taihu Lake.

  10. The effect of increased levels of carbon dioxide on chlorophyll fluorescence and photosynthetic pigments in pinus ponderosa

    SciTech Connect

    Anschel, D.

    1994-05-06

    Levels of atmospheric carbon dioxide have been increasing at an unprecedented rate in modern times. In response to this situation, we have initiated a long-term study of a forest species` response to elevated carbon dioxide levels. We have set up a facility for subjecting P. ponderosa to ambient, ambient + 175 {mu}1 1{sup {minus}1}, and ambient + 350 {mu}1 1{sup {minus}1} CO{sub 2}. This report specifically concentrates on the effects of elevated CO{sub 2} on the photosynthetic system, as indicated by chlorophyll fluorescence and pigment assays. We tested for intraspecific variability by selecting nine different families of trees from five different geographic areas of California. There are differential responses to carbon dioxide treatments which appear to be dependent upon the tree`s genotype, as indicated by the relative efficiencies of photochemical electron flow in photosystem II (Fv/Fm). During the same testing period Fv/Fm varied by as much as 21.1% relative to ambient in the treated groups. Total chlorophyll, chlorophyll {alpha} and carotenoid values all showed statistically significant (p<0.05) drops in the treatment groups regardless of genotype. Chlorophyll {alpha} at one time showed the most dramatic drop of 3 mg/m2 in the + 350 {mu}1 1{sup {minus}1} CO{sub 2} group versus the ambient. Findings for both photosynthetic pigments and chlorophyll fluorescence vary somewhat over the course of several months.

  11. Chlorophyll Fluorescence and Photon Yield of Oxygen Evolution in Iron-Deficient Sugar Beet (Beta vulgaris L.) Leaves 12

    PubMed Central

    Morales, Fermín; Abadía, Anunciación; Abadía, Javier

    1991-01-01

    The response of sugar beet (Beta vulgaris L.) leaves to iron deficiency can be described as consisting of two phases. In the first phase, leaves may lose a large part of their chlorophyll while maintaining a roughly constant efficiency of photosystem II photochemistry; ratios of variable to maximum fluorescence decreased by only 6%, and photon yields of oxygen evolution decreased by 30% when chlorophyll decreased by 70%. In the second phase, when chlorophyll decreased below a threshold level, iron deficiency caused major decreases in the efficiency of photosystem II photochemistry and in the photon yield of oxygen evolution. These decreases in photosystem II photochemical efficiency were found both in plants dark-adapted for 30 minutes and in plants dark-adapted overnight, indicating that photochemical efficiency cannot be repaired in that time scale. Decreases in photosystem II photochemical efficiency and in the photon yield of oxygen evolution were similar when measurements were made (a) with light absorbed by carotenoids and chlorophylls and (b) with light absorbed only by chlorophylls. Leaves of iron-deficient plants exhibited a room temperature fluorescence induction curve with a characteristic intermediate peak I that increases with deficiency symptoms. PMID:16668527

  12. Assessment of oak forest condition based on leaf biochemical variables and chlorophyll fluorescence.

    PubMed

    Rossini, Micol; Panigada, Cinzia; Meroni, Michele; Colombo, Roberto

    2006-11-01

    Pedunculate oak forests (Quercus robur L.) in the Ticino Regional Park, Italy, are declining as a result of insect attacks, summer droughts and air pollution. The assessment and monitoring of forest condition can provide a basis for managing and conserving forest ecosystems and thereby avoid loss of valuable natural resources. Currently, most forest assessments are limited to ground-based visual evaluations that are local and subjective. It is therefore difficult to compare data collected by different crews or to define reliable trends over years. We examined vegetation variables that can be quantitatively estimated by remote observations and, thus, are suitable for objective monitoring over extended forested areas. We found that total chlorophyll (Chl) concentration is the most suitable variable for assessing pedunculate oak decline. It is highly correlated with visual assessments of discoloration. Furthermore, Chl concentration can be accurately estimated from leaf optical properties, making it feasible to map Chl concentration at the canopy level from satellite and airborne remote observations.

  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

    NASA Technical Reports Server (NTRS)

    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. Estimation of chlorophyll-a concentration in turbid productive waters using airborne hyperspectral data.

    PubMed

    Moses, Wesley J; Gitelson, Anatoly A; Perk, Richard L; Gurlin, Daniela; Rundquist, Donald C; Leavitt, Bryan C; Barrow, Tadd M; Brakhage, Paul

    2012-03-15

    Algorithms based on red and near infra-red (NIR) reflectances measured using field spectrometers have been previously shown to yield accurate estimates of chlorophyll-a concentration in turbid productive waters, irrespective of variations in the bio-optical characteristics of water. The objective of this study was to investigate the performance of NIR-red models when applied to multi-temporal airborne reflectance data acquired by the hyperspectral sensor, Airborne Imaging Spectrometer for Applications (AISA), with non-uniform atmospheric effects across the dates of data acquisition. The results demonstrated the capability of the NIR-red models to capture the spatial distribution of chlorophyll-a in surface waters without the need for atmospheric correction. However, the variable atmospheric effects did affect the accuracy of chlorophyll-a retrieval. Two atmospheric correction procedures, namely, Fast Line-of-sight Atmospheric Adjustment of Spectral Hypercubes (FLAASH) and QUick Atmospheric Correction (QUAC), were applied to AISA data and their results were compared. QUAC produced a robust atmospheric correction, which led to NIR-red algorithms that were able to accurately estimate chlorophyll-a concentration, with a root mean square error of 5.54 mg m(-3) for chlorophyll-a concentrations in the range 2.27-81.17 mg m(-3). Copyright © 2011 Elsevier Ltd. All rights reserved.

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

    NASA Technical Reports Server (NTRS)

    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.

  16. Effects of bisphenol A on growth, photosynthesis and chlorophyll fluorescence in above-ground organs of soybean seedlings.

    PubMed

    Qiu, Zhiyong; Wang, Lihong; Zhou, Qing

    2013-01-01

    Bisphenol A (BPA) is a representatively endocrine disruptor, which shows a highly toxic effect on life system. Its potential toxicity on plants that are the primary producers in earth's ecosystem is not well documented. Here, the effects of BPA on the growth, photosynthesis, content of chlorophyll (Chl), initial fluorescence (F(0)), maximal photochemical efficiency (F(v)/F(m)), effective quantum yield of photosystem II (Φ(PSII)) and photosynthetic electron transport rate (ETR) in soybean seedlings were investigated by using gas exchange measurement system and chlorophyll fluorometer to understand the toxic effect of BPA on plants. It was found that when soybean seedlings were treated with BPA at the low concentration (1.5 mg L(-1)), the growth indices (the plant height, fresh and dry weights of stems, fresh and dry weights of leaves, leaf area) were increased obviously compared with those of the control, which was not related with the photosynthesis, the content of Chl and the chlorophyll fluorescence. When soybean seedlings were treated with BPA at the high concentrations (7.0, 12.0, 17.2 and 50.0 mg L(-1)), the growth indices, net photosynthetic rate, the content of chlorophyll, F(v)/F(m), Φ(PSII), ETR were decreased, while F(0) was increased, compared with those of the control. Obviously, BPA at the high concentrations showed the toxic effect on soybean seedlings. The results from correlation analysis indicated that the inhibition in the growth of soybean seedlings treated with BPA was related to the decrease in photosynthesis because of the decrease in the content of chlorophyll and the change in chlorophyll fluorescence. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2005-11-01

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

  1. [Effect of dibromothymoquinone on chlorophyll a fluorescence in Chlamydomonas reinhardtii cells incubated in complete or sulfur-depleted medium].

    PubMed

    Volgusheva, A A; Kukarskikh, G P; Antal, T K; Lavrukhina, O G; Krendeleva, T E; Rubin, A B

    2008-01-01

    The influence of dibromothymoquinone on chlorophyll fluorescence was studied in Chlamydomonas reinhardtii cells using PAM and PEA fluorometers. The reagent affected differently control cells incubated in complete medium and S-starved cells. Thus, the fluorescence yield in the control essentially increased in the presence of dibromothymoquinone, which can be due to the inactivation of light-harvesting complex II protein kinase, followed by the suppression of membrane transition from high-fluorescence state 1 to low-fluorescence state 2. On the contrary, S-starved cells with membranes in state 2 showed a lower fluorescence yield in the presence of dibromothymoquinone than without it. The JIP test of OJIP fluorescence transients suggests that dibromothymoquinone inhibits both light-harvesting complex II kinase and photosynthetic electron transport when added to control, while in starved cells, it acts predominantly as an electron acceptor.

  2. Study of the effect of reducing conditions on the initial chlorophyll fluorescence rise in the green microalgae Chlamydomonas reinhardtii.

    PubMed

    Antal, T K; Kolacheva, A; Maslakov, A; Riznichenko, G Yu; Krendeleva, T E; Rubin, A B

    2013-03-01

    Incubation of Chlamydomonas reinhardtii cells under nutrient deficiency results in the faster initial rise in the light-induced chlorophyll fluorescence kinetic curve. We showed that short-term anaerobic incubation of algal cells altered initial fluorescence in a way similar to nutrient starvation, suggesting an important role of the plastoquinones redox state in the observed effect. Bi-component analysis of highly resolved initial fluorescence rise kinetics in sulfur- or oxygen-depleted C. reinhardtii cells suggested that one of the mechanisms underlying the observed phenomenon involves primary closure (photochemical inactivation via Qa reduction) of β-type PSII as compared to α-PSII. Moreover, results of modeling of the fluorescence curve brought us to the conclusion that accumulation of closed centers in α-PSII supercomplexes may also cause a faster initial fluorescence rise. The observed correlations between nutrient supply rate and initial fluorescence rise pattern in green algae can serve to characterize culture nutritional status in vivo.

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

    NASA Astrophysics Data System (ADS)

    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

  4. Color measurements as a reliable method for estimating chlorophyll degradation to phaeopigments.

    PubMed

    Sanmartín, P; Villa, F; Silva, B; Cappitelli, F; Prieto, B

    2011-07-01

    The application of biocides is a traditional method of controlling biodecay of outdoor cultural heritage. Chlorophyll degradation to phaeopigments is used to test the biocidal efficacy of the antimicrobial agents. In the present study, the usefulness of color measurements in estimating chlorophyll degradation was investigated. An aeroterrestrial stone biofilm-forming cyanobacterium of the genus Nostoc was chosen as test organism, comparing its different behaviour in both planktonic and biofilm mode of growth against the isothiazoline biocide Biotin T®. Changes in A(435 nm)/A(415 nm) and A(665 nm)/A(665a nm) and in the chlorophyll a and adenosine triphosphate (ATP) cell content were compared with the variations in the CIELAB color parameters (L*, a*, b*, C*(ab) and h(ab)). Our findings showed that both the phaeophytination indexes are useful in describing degradation of chlorophyl a to phaeopigments. Moreover, the CIELAB color parameters represented an effective tool in describing chlorophyll degradation. L* CIELAB parameter appeared to be the most informative parameter in describing the biocidal activity of Biotin T® against Nostoc sp. in both planktonic and biofilm mode of growth.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  6. New Methods for Retrieval of Chlorophyll Red Fluorescence from Hyperspectral Satellite Instruments: Simulations and Application to GOME-2 and SCIAMACHY

    NASA Technical Reports Server (NTRS)

    Joiner, Joanna; Yoshida, Yasuko; Guanter, Luis; Middleton, Elizabeth M.

    2016-01-01

    Global satellite measurements of solar-induced fluorescence (SIF) from chlorophyll over land and ocean have proven useful for a number of different applications related to physiology, phenology, and productivity of plants and phytoplankton. Terrestrial chlorophyll fluorescence is emitted throughout the red and far-red spectrum, producing two broad peaks near 683 and 736nm. From ocean surfaces, phytoplankton fluorescence emissions are entirely from the red region (683nm peak). Studies using satellite-derived SIF over land have focused almost exclusively on measurements in the far red (wavelengths greater than 712nm), since those are the most easily obtained with existing instrumentation. Here, we examine new ways to use existing hyperspectral satellite data sets to retrieve red SIF (wavelengths less than 712nm) over both land and ocean. Red SIF is thought to provide complementary information to that from the far red for terrestrial vegetation. The satellite instruments that we use were designed to make atmospheric trace-gas measurements and are therefore not optimal for observing SIF; they have coarse spatial resolution and only moderate spectral resolution (0.5nm). Nevertheless, these instruments, the Global Ozone Monitoring Instrument 2 (GOME-2) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY), offer a unique opportunity to compare red and far-red terrestrial SIF at regional spatial scales. Terrestrial SIF has been estimated with ground-, aircraft-, or satellite-based instruments by measuring the filling-in of atmospheric andor solar absorption spectral features by SIF. Our approach makes use of the oxygen (O2) gamma band that is not affected by SIF. The SIF-free O2 gamma band helps to estimate absorption within the spectrally variable O2 B band, which is filled in by red SIF. SIF also fills in the spectrally stable solar Fraunhofer lines (SFLs) at wavelengths both inside and just outside the O2 B band, which further helps

  7. New Methods for Retrieval of Chlorophyll Red Fluorescence from Hyperspectral Satellite Instruments: Simulations and Application to GOME-2 and SCIAMACHY

    NASA Technical Reports Server (NTRS)

    Joiner, Joanna; Yoshida, Yasuko; Guanter, Luis; Middleton, Elizabeth M.

    2016-01-01

    Global satellite measurements of solar-induced fluorescence (SIF) from chlorophyll over land and ocean have proven useful for a number of different applications related to physiology, phenology, and productivity of plants and phytoplankton. Terrestrial chlorophyll fluorescence is emitted throughout the red and far-red spectrum, producing two broad peaks near 683 and 736nm. From ocean surfaces, phytoplankton fluorescence emissions are entirely from the red region (683nm peak). Studies using satellite-derived SIF over land have focused almost exclusively on measurements in the far red (wavelengths greater than 712nm), since those are the most easily obtained with existing instrumentation. Here, we examine new ways to use existing hyperspectral satellite data sets to retrieve red SIF (wavelengths less than 712nm) over both land and ocean. Red SIF is thought to provide complementary information to that from the far red for terrestrial vegetation. The satellite instruments that we use were designed to make atmospheric trace-gas measurements and are therefore not optimal for observing SIF; they have coarse spatial resolution and only moderate spectral resolution (0.5nm). Nevertheless, these instruments, the Global Ozone Monitoring Instrument 2 (GOME-2) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY), offer a unique opportunity to compare red and far-red terrestrial SIF at regional spatial scales. Terrestrial SIF has been estimated with ground-, aircraft-, or satellite-based instruments by measuring the filling-in of atmospheric andor solar absorption spectral features by SIF. Our approach makes use of the oxygen (O2) gamma band that is not affected by SIF. The SIF-free O2 gamma band helps to estimate absorption within the spectrally variable O2 B band, which is filled in by red SIF. SIF also fills in the spectrally stable solar Fraunhofer lines (SFLs) at wavelengths both inside and just outside the O2 B band, which further helps

  8. Effects of Dihydroartemisinin and Artemether on the Growth, Chlorophyll Fluorescence, and Extracellular Alkaline Phosphatase Activity of the Cyanobacterium Microcystis aeruginosa.

    PubMed

    Wang, Shoubing; Xu, Ziran

    2016-01-01

    Increased eutrophication in the recent years has resulted in considerable research focus on identification of methods for preventing cyanobacterial blooms that are rapid and efficient. The objectives of this study were to investigate the effects of dihydroartemisinin and artemether on the growth of Microcystis aeruginosa and to elucidate its mode of action. Variations in cell density, chlorophyll a, soluble protein, malondialdehyde, extracellular alkaline phosphatase activity (APA), and chlorophyll fluorescence parameters (Fv/Fm, ΦPSII, ETR, rapid light curves, fast chlorophyll fluorescence curves on fluorescence intensity, and relative variable fluorescence) were evaluated by lab-cultured experiments. Our results demonstrated that both dihydroartemisinin and artemether inhibited the growth of M.aeruginosa by impairing the photosynthetic center in photosystem II and reducing extracellular APA, with a higher sensitivity exhibited toward artemether. The inhibitory effects of dihydroartemisinin on M.aeruginosa increased with concentration, and the maximum growth inhibitory rate was 42.17% at 24 mg·L-1 after 120h exposure, whereas it was 55.72% at 6 mg·L-1 artemetherafter 120h exposure. Moreover, the chlorophyll fluorescence was significantly inhibited (p<0.05) after 120h exposure to 12 and 24 mg·L-1 dihydroartemisinin. Furthermore, after 120h exposure to 6 mg·L-1 artemether, Fv/Fm, ΦPSII, ETR and rETRmax showed a significant decrease (p<0.01) from initial values of 0.490, 0.516, 17.333, and 104.800, respectively, to 0. One-way analysis of variance showed that 6 mg·L-1 artemether and 24 mg·L-1 dihydroartemisinin had significant inhibitory effects on extracellular APA (p<0.01). The results of this study would be useful to further studies to validate the feasibility of dihydroartemisinin and artemether treatment to inhibit overall cyanobacterial growth in water bodies, before this can be put into practice.

  9. Effects of Dihydroartemisinin and Artemether on the Growth, Chlorophyll Fluorescence, and Extracellular Alkaline Phosphatase Activity of the Cyanobacterium Microcystis aeruginosa

    PubMed Central

    Wang, Shoubing; Xu, Ziran

    2016-01-01

    Increased eutrophication in the recent years has resulted in considerable research focus on identification of methods for preventing cyanobacterial blooms that are rapid and efficient. The objectives of this study were to investigate the effects of dihydroartemisinin and artemether on the growth of Microcystis aeruginosa and to elucidate its mode of action. Variations in cell density, chlorophyll a, soluble protein, malondialdehyde, extracellular alkaline phosphatase activity (APA), and chlorophyll fluorescence parameters (Fv/Fm, ΦPSII, ETR, rapid light curves, fast chlorophyll fluorescence curves on fluorescence intensity, and relative variable fluorescence) were evaluated by lab-cultured experiments. Our results demonstrated that both dihydroartemisinin and artemether inhibited the growth of M.aeruginosa by impairing the photosynthetic center in photosystem II and reducing extracellular APA, with a higher sensitivity exhibited toward artemether. The inhibitory effects of dihydroartemisinin on M.aeruginosa increased with concentration, and the maximum growth inhibitory rate was 42.17% at 24 mg·L-1 after 120h exposure, whereas it was 55.72% at 6 mg·L-1 artemetherafter 120h exposure. Moreover, the chlorophyll fluorescence was significantly inhibited (p<0.05) after 120h exposure to 12 and 24 mg·L-1 dihydroartemisinin. Furthermore, after 120h exposure to 6 mg·L-1 artemether, Fv/Fm, ΦPSII, ETR and rETRmax showed a significant decrease (p<0.01) from initial values of 0.490, 0.516, 17.333, and 104.800, respectively, to 0. One-way analysis of variance showed that 6 mg·L-1 artemether and 24 mg·L-1 dihydroartemisinin had significant inhibitory effects on extracellular APA (p<0.01). The results of this study would be useful to further studies to validate the feasibility of dihydroartemisinin and artemether treatment to inhibit overall cyanobacterial growth in water bodies, before this can be put into practice. PMID:27755566

  10. Assessment of the relationship between chlorophyll fluorescence and photosynthesis across scales from measurements and simulations

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Guanter, L.; Berry, J. A.; Tol, C. V. D.

    2016-12-01

    Solar-induced chlorophyll fluorescence (SIF) is a novel optical tool for assessment of terrestrial photosynthesis (GPP). Recent work have shown the strong link between GPP and satellite retrievals of SIF at broad scales. However, critical gaps remain between short term small-scale mechanistic understanding and seasonal global observations. In this presentation, we provide a model-based analysis of the relationship between SIF and GPP across scales for diverse vegetation types and a range of meteorological conditions, with the ultimate focus on reproducing the environmental conditions during remote sensing measurements. The coupled fluorescence-photosynthesis model SCOPE is used to simulate GPP and SIF at the both leaf and canopy levels for 13 flux sites. Analyses were conducted to investigate the effects of temporal scaling, canopy structure, overpass time, and spectral domain on the relationship between SIF and GPP. The simulated SIF is highly non-linear with GPP at the leaf level and instantaneous time scale and tends to linearize when scaling to the canopy level and daily to seasonal scales. These relationships are consistent across a wide range of vegetation types. The relationship between SIF and GPP is primarily driven by absorbed photosynthetically active radiation (APAR), especially at the seasonal scale, although the photosynthetic efficiency also contributes to strengthen the link between them. The linearization of their relationship from leaf to canopy and averaging over time is because the overall conditions of the canopy fall within the range of the linear responses of GPP and SIF to light and the photosynthetic capacity. Our results further show that the top-of-canopy relationships between simulated SIF and GPP have similar linearity regardless of whether we used the morning or midday satellite overpass times. These findings are confirmed by field measurements. In addition, the simulated red SIF at 685 nm has a similar relationship with GPP as that of

  11. Satellite Solar-induced Chlorophyll Fluorescence Reveals Drought Onset Mechanisms: Insights from Two Contrasting Extreme Events

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Fu, R.; Dickinson, R. E.; Joiner, J.; Frankenberg, C.; Gu, L.; Xia, Y.; Fernando, N.

    2015-12-01

    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 Instrument 2 (GOME-2) closely resembled drought intensity maps from the US 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 year-long below-normal precipitation. In contrast, for the central Great Plains drought, warmer temperatures and ample 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.

  12. Assessment of anthocyanins in grape (Vitis vinifera L.) berries using a noninvasive chlorophyll fluorescence method.

    PubMed

    Agati, Giovanni; Meyer, Sylvie; Matteini, Paolo; Cerovic, Zoran G

    2007-02-21

    Anthocyanins (Anths) in grape (Vitis vinifera L.) berries harvested at véraison from Pinot Noir and Pinot Meunier cultivars were assessed nondestructively by measuring chlorophyll fluorescence (ChlF) excitation spectra. With increasing Anth content, less excitation light was transmitted to the deeper Chl layers, and thus the ChlF signal decreased proportionally. By applying Beer-Lambert's law, the logarithm of the ratio between the fluorescence excitation spectra (log FER) from a green and a red berry gave the in vivo absorption spectrum of Anths, which peaked at about 540 nm. Absolute quantitative nondestructive determination of Anths for each berry was obtained by the log FER calculated for two excitation wavelengths, 540 and 635 nm (absorbed and not-absorbed by Anths, respectively) of ChlF at 685 nm. Over a range of skin colors going from green to purple, the relationship between the log [ChlF(635)/ChlF(540)] and the Anth concentration of berry extracts was fairly well fitted (r 2 = 0.92) using a power function. Reflectance spectra on the same berry samples were also measured, and Anth reflectance indices, which were originally developed for apples and table grapes, were derived. The log FER Anth index was superior to the reflectance-ratio-based index, but was as good as the color index for red grapes (CIRG) calculated from the whole visible reflectance spectrum. The proposed log FER method, applied by means of suitable portable devices, may represent a new, rapid, and noninvasive tool for the assessment of grape phenolic maturity in vineyards.

  13. Nondestructive evaluation of anthocyanins in olive (Olea europaea) fruits by in situ chlorophyll fluorescence spectroscopy.

    PubMed

    Agati, Giovanni; Pinelli, Patrizia; Cortés Ebner, Solange; Romani, Annalisa; Cartelat, Aurélie; Cerovic, Zoran G

    2005-03-09

    Anthocyanins (Anths) in olive (Olea europaea L.) fruits at different degrees of pigmentation were assessed nondestructively by measuring chlorophyll fluorescence (ChlF). The method is based on the comparison of the ChlF excitation spectra from olives with different pigmentation from green to green-red, reddish-purple, and purple. The logarithm of the ratio between the fluorescence excitation spectra (logFER) from two different colored zones gave the difference in the absorption spectrum between them. The absorbance spectrum derived from the logFER between a red olive and the same olive devoid of the skin showed the typical Anth green band (at 550 nm). It matched that recorded by microspectrophotometry on a single pulp cell and the in vitro absorbance spectrum of the olive skin extract. As expected, the in vivo Anths absorption maximum increased in intensity going from less to more mature olives and was higher in the sun-exposed olive side with respect to the sun-shaded side. Absolute quantitative nondestructive determination of Anths for each olive sample was obtained by the logFER calculated for two excitation wavelengths, 550 and 625 nm, of ChlF at 740 nm. Going from green to purple skin colors, the Log[ChlF(625)/ChlF(550)] was fairly well-correlated to the extract Anths concentration. Finally, the relationship between the Anths and the other main phenolics present in the olives analyzed by high-performance liquid chromatography was evaluated. The main result was a net increase of verbascoside with increasing Anths content. On the basis of our results, the development of a new rapid and noninvasive method for the monitoring of olive development and ripening can be envisaged.

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

    PubMed

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

    2014-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2017-01-01

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

  16. Response to ozone in two lettuce varieties on chlorophyll a fluorescence, photosynthetic pigments and lipid peroxidation.

    PubMed

    Calatayud, Angeles; Barreno, Eva

    2004-06-01

    The effect of different O3 concentrations on two lettuce (Lactuca sativa L.) varieties (Valladolid and Morella) was investigated through chlorophyll (Chl) a fluorescence parameters, photosynthetic pigments (Chl a, b and total carotenoid), lipid peroxidation and crop yield. Ozone fumigation caused: a decrease in maximum quantum yield of photosystem II (PSII) photochemistry (Fv/Fm) in mature leaves, a reduction in the non-cyclic electron flow (phiPSII) and a lower capacity to reoxidize the QA pool (qP). These reductions were significant in the Valladolid var. but not in the Morella var. A significant decrease in Chl a, b and in the total carotenoids was observed in the Valladolid var. but not in the Morella var. mainly under O3 fumigation conditions. We observed that the NPQ parameter did not increase in parallel to the qP reduction seen in the Valladolid var. O3 fumigation with respect to air charcoal filtered air conditions. This fact could be associated with a lower capacity for dissipation of non-radiative excess energy and it may be closely correlated with significant decreases in photosynthetic pigment concentration. A decrease in NPQ from air ozone-free to ozone fumigation in the Morella var. can be explained by the need to maintain the photochemical quenching under O3 stress. It may also be associated with a slight increase in photosynthetic pigments. The differences between the two varieties may indicate that the Valladolid var. is more susceptible to O3 damage.

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

    PubMed

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

    2016-09-01

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

  18. Nonphotochemical Chlorophyll Fluorescence Quenching: Mechanism and Effectiveness in Protecting Plants from Photodamage1

    PubMed Central

    2016-01-01

    We review the mechanism underlying nonphotochemical chlorophyll fluorescence quenching (NPQ) and its role in protecting plants against photoinhibition. This review includes an introduction to this phenomenon, a brief history of major milestones in our understanding of NPQ, definitions, and a discussion of quantitative measurements of NPQ. We discuss the current knowledge and unknown aspects in the NPQ scenario, including the following: ΔpH, the proton gradient (trigger); light-harvesting complex II (LHCII), PSII light harvesting antenna (site); and changes in the antenna induced by ΔpH (change), which lead to the creation of the quencher. We conclude that the minimum requirements for NPQ in vivo are ΔpH, LHCII complexes, and the PsbS protein. We highlight the most important unknown in the NPQ scenario, the mechanism by which PsbS acts upon the LHCII antenna. Finally, we describe a novel, emerging technology for assessing the photoprotective “power” of NPQ and the important findings obtained through this technology. PMID:26864015

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

    PubMed

    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.

  20. Assessment of phytotoxicity of anthracene in soybean (Glycine max) with a quick method of chlorophyll fluorescence.

    PubMed

    Tomar, R S; Sharma, A; Jajoo, A

    2015-07-01

    A decrease in photosynthetic efficiency may indicate the toxic effects of environmental pollutants on higher plants. Measurement of chlorophyll (Chl) a fluorescence to assess the performance of photosystem II (PSII) was used as an bioindicator of toxicity of the polycyclic aromatic hydrocarbon (PAH) anthracene (ANT) in soybean plants. The results revealed that ANT treatment caused a reduction in quantum yield of PSII, damage to the oxygen evolving complex, as well as a significant reduction in performance index of PSII. However, change in performance index was more prominent, and it seems that the performance index is a more sensitive parameter to environmental contaminants. Moreover, a change in heterogeneity of PSII was also observed. The number of active reaction centres decreased with increasing concentration of ANT, as secondary plastoquinone reducing centres were converted into non-reducing centres, and PSIIα centres were converted into PSIIβ and PSIIγ centres. The influence of ANT on PSII heterogeneity could be an important reason for reductions in the PSII performance.

  1. Wavelet analysis of pulse-amplitude-modulated chlorophyll fluorescence for differentiation of plant samples.

    PubMed

    Guo, Ya; Zhou, Yesen; Tan, Jinglu

    2015-04-07

    Pulse-amplitude-modulated (PAM) chlorophyll fluorescence (ChlF) from photosystem II (PSII) of plants has been routinely measured for the analysis of photosynthesis and environmental changes. PAM ChlF from PSII is non-stationary and has time-varying frequency characteristics; however, existing analysis of PAM ChlF has been limited to selected characteristic values in the time domain. Wavelet transform is recognized as an efficient tool for analyzing non-stationary signals. In this research, an attempt was made to analyze PAM ChlF through wavelet transform. Features of PAM ChlF signals were computed from wavelet decomposition to classify two tree species and to detect chilling and detachment stresses. The wavelet-based features were compared with the commonly-used maximal PSII efficiency Fv/Fm. Both the wavelet-based features and Fv/Fm could effectively classify two tree species, but the former showed superiority than the latter in detecting the stresses. Wavelet transform revealed chilling stress earlier than Fv/Fm and detected detachment stress Fv/Fm failed to show. The results show that wavelet transform is a useful technique for analysis of PAM ChlF. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Isolation of Chlamydomonas reinhardtii mutants with altered mitochondrial respiration by chlorophyll fluorescence measurement.

    PubMed

    Massoz, Simon; Larosa, Véronique; Horrion, Bastien; Matagne, René F; Remacle, Claire; Cardol, Pierre

    2015-12-10

    The unicellular green alga Chlamydomonas reinhardtii is a model organism for studying energetic metabolism. Most mitochondrial respiratory-deficient mutants characterized to date have been isolated on the basis of their reduced ability to grow in heterotrophic conditions. Mitochondrial deficiencies are usually partly compensated by adjustment of photosynthetic activity and more particularly by transition to state 2. In this work, we explored the opportunity to select mutants impaired in respiration and/or altered in dark metabolism by measuring maximum photosynthetic efficiency by chlorophyll fluorescence analyses (FV/FM). Out of about 2900 hygromycin-resistant insertional mutants generated from wild type or from a mutant strain deficient in state transitions (stt7 strain), 22 were found to grow slowly in heterotrophic conditions and 8 of them also showed a lower FV/FM value. Several disrupted coding sequences were identified, including genes coding for three different subunits of respiratory-chain complex I (NUO9, NUOA9, NUOP4) or for isocitrate lyase (ICL1). Overall, the comparison of respiratory mutants obtained in wild-type or stt7 genetic backgrounds indicated that the FV/FM value can be used to isolate mutants severely impaired in dark metabolism.

  3. Scaling effect on the estimation of chlorophyll content using narrow band NDVIs based on radiative transfer model

    NASA Astrophysics Data System (ADS)

    Wang, Hong; Shi, Runhe; Liu, Pudong; Cong, Zhou

    2015-09-01

    The aim of this work is to use narrow band normalized difference vegetation indices to compare the estimations of chlorophyll contents at foliar level and canopy level, through a large number of simulated canopy reflectance spectra under different chlorophyll contents based on PROSPECT model and SAIL model. 10 narrow band NDVIs were selected at the identified ranges that can effectively assess foliar chlorophyll content. We analyzed the correlations between canopy chlorophyll contents and the ten narrow band NDVIs firstly, and then analyze these indices' sensitivities to all canopy parameters, the adaptation of the 10 narrow band NDVIs used in assessing the canopy chlorophyll content were evaluated finally. We found that only two narrow band NDVIs (i.e., NDVI(875, 725) and NDVI(900,720)) can be applied for the estimation of chlorophyll contents at canopy level.

  4. Demonstration of thermal dissipation of absorbed quanta during energy-dependent quenching of chlorophyll fluorescence in photosynthetic membranes.

    PubMed

    Yahyaoui, W; Harnois, J; Carpentier, R

    1998-11-27

    When plant leaves or chloroplasts are exposed to illumination that exceeds their photosynthetic capacity, photoprotective mechanisms such as described by the energy-dependent (non-photochemical) quenching of chlorophyll fluorescence are involved. The protective action is attributed to an increased rate constant for thermal dissipation of absorbed quanta. We applied photoacoustic spectroscopy to monitor thermal dissipation in spinach thylakoid membranes together with simultaneous measurement of chlorophyll fluorescence in the presence of inhibitors of opposite action on the formation of delta pH across the thylakoid membrane (tentoxin and nigericin/valinomycin). A linear relationship between the appearance of fluorescence quenching during formation of the delta pH and the reciprocal variation of thermal dissipation was demonstrated. Dicyclohexylcarbodiimide, which is known to prevent protonation of the minor light-harvesting complexes of photosystem II, significantly reduced the formation of fluorescence quenching and the concurrent increase in thermal dissipation. However, the addition of exogenous ascorbate to activate the xanthophyll de-epoxidase increased non-photochemical fluorescence quenching without affecting the measured thermal dissipation. It is concluded that a portion of energy-dependent fluorescence quenching that is independent of de-epoxidase activity can be readily measured by photoacoustic spectroscopy as an increase in thermal deactivation processes.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. A linear method for the retrieval of sun-induced chlorophyll fluorescence from GOME-2 and SCIAMACHY data

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Global retrievals of near-infrared sun-induced chlorophyll fluorescence (SIF) have been achieved in the last 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 (GOME-2) and the SCanning Imaging Absorption SpectroMeter for Atmospheric ChartographY (SCIAMACHY). Building upon the previous work by Joiner et al. (2013), our approach solves existing issues in the retrieval such as the non-linearity of the forward model and the arbitrary selection of the number of free parameters. In particular, we use a backward elimination algorithm 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 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 examine uncertainties and use our GOME-2 retrievals to show empirically the low sensitivity of the SIF retrieval to cloud contamination.

  7. A linear method for the retrieval of sun-induced chlorophyll fluorescence from GOME-2 and SCIAMACHY data

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-06-01

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

  9. [Influence of dehydration and diurnal variation on characteristics of chlorophyll fluorescence of leaves in Haloxylon ammodendron and H. persicum].

    PubMed

    Shen, Liang; Chen, Jun; Liu, Sai; Xu, Rong; Xu, Chang-qing; Liu, Tong-ning

    2015-08-01

    To evaluate the ecological adaptation mechanism of Haloxylon ammodendron and H. persicum from Ningxia, the host of Cistanche deserticola, the chlorophyll fluorescence under dehydration and diurnal variation was determined by IMAGING-PAM method. The results showed that H. ammodendron had higher photosynthetic electron transport activity (Fv/Fm), photosynthetic efficiency (qP), and PS II electron transport activity (ETR) than H. persicum. After 48 h dehydration, the chlorophyll fluorescence and water-retaining property of H. ammodendron were significantly higher than those of H. persicum. The significant difference in diurnal variation between H. ammo- dendron and H. persicum was observed and a 'V' trend was exhibited. It suggested that H. ammodendron had a stronger ability to adapt to the environment and had wider distribution, while H. persicum was limited by water and light and had narrow distribution.

  10. [Effects of perchlorate on growth and chlorophyll fluorescence parameters of Alternanthera philoxeroides].

    PubMed

    Xie, Yin-feng; Cai, Xian-lei; Liu, Wei-long; Deng, Wei

    2009-08-15

    Perchlorate is a new emerging persistent pollutant, while no studies about its effects on plants have been reported both home and abroad. In order to explore the effects of perchlorate on growth and physiology of aquatic plant, Alternanthera philoxeroides were treated by 1/20 Hoagland nutrient solution with different concentrations (0, 1, 5, 20, 100, 500 mg/L) of ClO4- under the controlled conditions. The results showed as follow. (1) Under perchlorate treatment, relative growth yield,dry weight of root,shoot and leaves were inhibited at different degrees, in which root biomass under different treatments showed significant difference to the control. After treatment for 40 d, relative growth yield of different treatments at concentration from 1 mg/L to 500 mg/L were about 61.6%, 60.8%, 53.1%, 20.4% and 3.3% separately of the control. And the order of variation coefficients of biomass in different organ were as follows: leaf > root biomass > stem; the relationship of biomass allocation in different organs of Alternanthera philoxeroides under perchlorate treatment changed, and the proportion of stem biomass increased,while leaf decreased, in which 100 and 500 mg/L ClO4- treatment showed significant difference to the control. (2) Under perchlorate treatment, young leaves of Alternanthera philoxeroides presented injury symptoms (such as parietal roiling reversely, leaf edge getting black and withered etc), and the damaged degree of Alternanthera philoxeroides increased with the increase of treatment concentration and time. (3) Under perchlorate treatment, the relative chlorophyll content (SPAD value), primary maximal PSII efficiency(Fv/Fm), efficiency of excitation capture by open PSII centre (F'v,/F'm), actual photochemical efficiency of PSII (phi(PS II)), electron transport rate (ETR), maximal electron transport rate(ETR ,) and other indexes were inhibited at different degrees. SPAD and chlorophyll fluorescence parameters (phi(PS II)) etc. could be used as sensitive

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

    PubMed

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

    2012-05-15

    Chlorophyll a fluorescence of microalgae is a compelling indicator of toxicity of dissolved water contaminants, because it is easily measured and responds rapidly. While different chl a fluorescence parameters have been examined, most studies have focused on single species and/or a narrow range of toxins. We assessed the utility of one chl a fluorescence parameter, the maximum quantum yield of PSII (F(v)/F(m)), for detecting effects of nine environmental pollutants from a range of toxin classes on 5 commonly found freshwater algal species, as well as the USEPA model species, Pseudokirchneriella subcapitata. F(v)/F(m) declined rapidly over <20 min in response to low concentrations of photosynthesis-specific herbicides Diuron(®) and metribuzin (both <40 nM), atrazine (<460 nM) and terbuthylazine (<400 nM). However, F(v)/F(m) also responded rapidly and in a dose-dependent way to toxins glyphosate (<90 μM), and KCN (<1 mM) which have modes of action not specific to photosynthesis. F(v)/F(m) was insensitive to 30-40 μM insecticides methyl parathion, carbofuran and malathion. Algal species varied in their sensitivity to toxins. No single species was the most sensitive to all nine toxins, but for six toxins to which algal F(v)/F(m) responded significantly, the model species P. subcapitata was less sensitive than other taxa. In terms of suppression of F(v)/F(m) within 80 min, patterns of concentration-dependence differed among toxins; most showed Michaelis-Menten saturation kinetics, with half-saturation constant (K(m)) values for the PSII inhibitors ranging from 0.14 μM for Diuron(®) to 6.6 μM for terbuthylazine, compared with a K(m) of 330 μM for KCN. Percent suppression of F(v)/F(m) by glyphosate increased exponentially with concentration. F(v)/F(m) provides a sensitive and easily-measured parameter for rapid and cost-effective detection of effects of many dissolved toxins. Field-portable fluorometers will facilitate field testing, however distinct responses

  12. Effects of DCMU on chlorophyll fluorescence ratio F685/F735 in marine red, brown and green algae

    NASA Astrophysics Data System (ADS)

    Wu, Bao-Gan; Zuo, Dong-Mei; Zang, Ru-Bo

    1996-03-01

    The chlorophyll fluorescence ratio F685/F735 in vivo can be a useful indicator for stress detection in higher plants and seaweeds. DCMU [3-(3,4-dichlorophenyl)-1, 1-dimethylurea] treatment influences this ratio. The effets of DCMU on F685/F735 of marine red, brown and green algae under excitation light of different wavelengths were investigated. In the brown algae, Laminaria japonica and Undaria pinnatifida, DCMU did not increase this ratio under blue light excitation but increased the ratio slightly under excitation by green light. For the red algae, Halymenia sinensis, DCMU increased the ratio markedly under both blue and green light excitation. The percentage increase could reach 50% (under green light excitation) and was due to unequal enhancement at the two emission maxima by DCMU. A fraction of chlorophyll which contributed to fluorescence in the 735 nm region was less sensitive to DCMU and was likely from photosystem I of red algae. In the green alga, Ulva pertusa, DCMU caused a slight increase in F685/F735 value under blue, green and red light. Green light excitation during DCMU treatment increased the ratio most (16%) but induced the lowest ratio in the control (without DCMU). It is proposed that a considerable fraction of fluorescence from the 735 nm region at room temperature may be emitted by the chlorophyll of photosystem I in red algae.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

  15. Age-dependent response of maize leaf segments to cadmium treatment: effect on chlorophyll fluorescence and phytochelatin accumulation.

    PubMed

    Drazkiewicz, Maria; Tukendorf, Anna; Baszyński, Tadeusz

    2003-03-01

    The relationship between the age of leaf tissue and response of the photosynthetic apparatus and phytochelatin accumulation to Cd treatment was studied. Studies were carried out with seedlings of Zea mays L. cv. Hidosil grown in the presence of 100-200 mumol/L Cd for 14 days under low light conditions. The third leaf was divided into 3 segments of equal length differing in the stage of tissue maturity and used for measurements of chlorophyll content, chlorophyll fluorescence, glutathione and phytochelatin content and Cd accumulation. A close relationship between the age of leaf tissue and response of the photosynthetic apparatus to Cd was shown. Cadmium (200 mumol/L) reduced photochemical processes more in older than younger leaf segments as seen in the Chl fluorescence parameters Fv/F0, and t1/2, while the chlorophyll fluorescence decrease ratio (Rfd) was inhibited more strongly in younger ones. Fv/Fm was slightly affected. Cd-induced enhancement of GSH content was correlated with higher phytochelatin accumulation to a greater extent in younger than in older leaf segments. Phytochelatin level corresponded to changes of photochemical processes in older leaves. The peptide thiol:Cd molar ratio for the phytochelatins varied depending on Cd concentration and age of leaf segments. The protective role of phytochelatins for the photosynthetic apparatus is discussed.

  16. A chlorophyll a fluorescence-based Lemna minor bioassay to monitor microbial degradation of nanomolar to micromolar concentrations of linuron.

    PubMed

    Hulsen, Kris; Minne, Veerle; Lootens, Peter; Vandecasteele, Paul; Höfte, Monica

    2002-06-01

    A plant-microbial bioassay, based on the aquatic macrophyte Lemna minor L. (duckweed), was used to monitor biodegradation of nano- and micromolar concentrations of the phenylurea herbicide linuron. After 7 days of exposure to linuron, log-logistic-based dose-response analysis revealed significant growth inhibition on the total frond area of L. minor when linuron concentrations > or = 80 nM were added to the bioassay. A plant-protective effect was obtained for all concentrations > 80 nM by inoculation with either a bacterial consortium or Variovorax paradoxus WDL1, which is probably the main actor in this consortium. The outcome of the plant-microbe-toxicant interaction was also assessed using pulse amplitude-modulated chlorophyll a fluorescence and chlorophyll a fluorescence imaging. Linuron toxicity to L. minor became apparent as a significant decrease in the effective quantum yield (Delta F/Fm') within 90 min after exposure of the plants to linuron concentrations > or = 160 nM. Inoculation of the bioassay with the linuron-degrading bacteria neutralized the effect on the effective quantum yield at concentrations > or = 160 nM, indicating microbial degradation of these concentrations. The chlorophyll a fluorescence-based Lemna bioassay described here offers a sensitive, fast and cost-effective approach to study the potential of biodegrading microorganisms to break down minute concentrations of photosynthesis-inhibiting xenobiotics.

  17. The comparison for leaf nitrogen estimating in rice by chlorophyll meters and reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Fenfang; Wang, Ke

    Handheld chlorophyll sensors is a very important technique to determine the timing and number of N applications, which can improve the fertilizer-N use efficiency and monitor leaf N status of irrigated rice. One solution-culture and two field experiments with four rice genotypes were conducted to obtain variables reflecting nitrogen (N) status at different developmental stages. The paper systemically compared SPAD indices calculated from the SPAD readings of various leaf positions and hyperspectral vegetation indices. The results showed that the indices RSI and RDSI were more reliable SPAD indices for estimating foliar N status in rice plant; In addition, from view of quickness and cheapness, chlorophyll meters are more suitable for estimating foliar N status in rice than reflectance spectroscopy on the basis of meeting accuracy requirements.

  18. Spectral Feature Analysis for Quantitative Estimation of Cyanobacteria Chlorophyll-A

    NASA Astrophysics Data System (ADS)

    Lin, Yi; Ye, Zhanglin; Zhang, Yugan; Yu, Jie

    2016-06-01

    In recent years, lake eutrophication caused a large of Cyanobacteria bloom which not only brought serious ecological disaster but also restricted the sustainable development of regional economy in our country. Chlorophyll-a is a very important environmental factor to monitor water quality, especially for lake eutrophication. Remote sensed technique has been widely utilized in estimating the concentration of chlorophyll-a by different kind of vegetation indices and monitoring its distribution in lakes, rivers or along coastline. For each vegetation index, its quantitative estimation accuracy for different satellite data might change since there might be a discrepancy of spectral resolution and channel center between different satellites. The purpose this paper is to analyze the spectral feature of chlorophyll-a with hyperspectral data (totally 651 bands) and use the result to choose the optimal band combination for different satellites. The analysis method developed here in this study could be useful to recognize and monitor cyanobacteria bloom automatically and accrately. In our experiment, the reflectance (from 350nm to 1000nm) of wild cyanobacteria in different consistency (from 0 to 1362.11ug/L) and the corresponding chlorophyll-a concentration were measured simultaneously. Two kinds of hyperspectral vegetation indices were applied in this study: simple ratio (SR) and narrow band normalized difference vegetation index (NDVI), both of which consists of any two bands in the entire 651 narrow bands. Then multivariate statistical analysis was used to construct the linear, power and exponential models. After analyzing the correlation between chlorophyll-a and single band reflectance, SR, NDVI respetively, the optimal spectral index for quantitative estimation of cyanobacteria chlorophyll-a, as well corresponding central wavelength and band width were extracted. Results show that: Under the condition of water disturbance, SR and NDVI are both suitable for quantitative

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

    PubMed

    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.

  20. Estimation of leaf chlorophyll content and the fraction of light absorption by chlorophyll using MODIS images and a radiative transfer model

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Xiao, X.; Braswell, B.; Linder, E.; Moore, B.

    2005-12-01

    Photosynthetically actively radiation (PAR) absorbed by leaf chlorophyll is used for photosynthesis, therefore, there is a need to quantify the fraction of PAR absorbed by leaf chlorophyll (FAPARchl) within a vegetation canopy. We recently developed a theoretical and modeling framework to estimate leaf chlorophyll content and FAPARchl.in a vegetation canopy The modeling framework coupled a leaf radiative transfer model (PROPSECT) with a canopy radiative transfer model (SAIL-2) and incorporated a Markov Chain Monte Carlo (MCMC) method (the Metropolis algorithm) for model inversion, which provides posterior distributions of retrieved variables. Our two-step procedure is: (1) to invert biophysical and biochemical variables (including leaf chlorophyll content) with the coupled PROSPECT+SAIL-2 (PROSAIL-2) model and multiple daily images (five spectral bands) from MODerate resolution Imaging Spectroradiometer (MODIS) sensor , (2) to reproduce MODIS spectral reflectance and to calculate FAPARchl with the inverted variables from step (1). We ran the PROSAIL-2 model for a deciduous broadleaf forest, an evergreen forest and an agricultural site using MODIS data in 2001-2003. The PROSAIL-2 -reproduced reflectance agrees well with observed MODIS reflectance for the five MODIS spectral bands. The retrieved variables (leaf area index, leaf chlorophyll content) were also evaluated with available literature data. Estimated FAPARchl is substantially lower than the fraction of PAR absorbed by leaf (FAPARleaf) and by vegetation canopy (FAPARcanopy). Biogeochemical models that use either the fraction of PAR absorbed by canopy (FAPARcanopy) or the fraction of PAR absorbed by leaf (FAPARleaf) in estimating gross and net primary production are likely to overestimate the amount of PAR used in photosynthesis process, which represents one large source of error and uncertainty. The results of this study highlight the needs of field works and the potential of a radiative transfer model

  1. Thermostability and photostability of photosystem II of the resurrection plant Haberlea rhodopensis studied by chlorophyll fluorescence.

    PubMed

    Georgieva, Katya; Maslenkova, Liliana

    2006-01-01

    The stability of PSII in leaves of the resurrection plant Haberlea rhodopensis to high temperature and high light intensities was studied by means of chlorophyll fluorescence measurements. The photochemical efficiency of PSII in well-hydrated Haberlea leaves was not significantly influenced by temperatures up to 40 degrees C. Fo reached a maximum at 50 degrees C, which is connected with blocking of electron transport in reaction center II. The intrinsic efficiency of PSII photochemistry, monitored as Fv/Fm was less vulnerable to heat stress than the quantum yield of PSII electron transport under illumination (phiPSII). The reduction of phiPSII values was mainly due to a decrease in the proportion of open PSII centers (qP). Haberlea rhodopensis was very sensitive to photoinhibition. The light intensity of 120 micromol m(-2) s(-1) sharply decreased the quantum yield of PSII photochemistry and it was almost fully inhibited at 350 micromol m(-2) s(-1). As could be expected decreased photochemical efficiency of PSII was accompanied by increased proportion of thermal energy dissipation, which is considered as a protective effect regulating the light energy distribution in PSII. When differentiating between the three components of qN it was evident that the energy-dependent quenching, qE, was prevailing over photoinhibitory quenching, qI, and the quenching related to state 1-state 2 transitions, qT, at all light intensities at 25 degrees C. However, the qE values declined with increasing temperature and light intensities. The qI was higher than qE at 40 degrees C and it was the major part of qN at 45 degrees C, indicating a progressing photoinhibition of the photosynthetic apparatus.

  2. [Effects of suspended silts in waters on the growth and chlorophyll fluorescence characteristics of Hydrilla verticillata].

    PubMed

    Li, Qiang; Wang, Guo-Xiang

    2009-10-01

    Silt particles smaller than 100 microm in diameter were used to make the waters with a turbidity of 30 NTU, 60 NTU, and 90 NTU. Hydrilla verticillata seedlings were planted in the turbid waters, and their branch length, branch number, and fresh mass were measured at definite periods of time. In the meanwhile, the leaf chlorophyll fluorescence parameters were determined in situ by a submersible pulse-amplitude modulated (PAM) fluorometer (Walz GmbH, Effeltrich, Germany). With the increase of water turbidity, the branch number of the seedlings decreased remarkably, biomass also decreased, but branch length increased significantly. In turbid waters, the Fv/Fm value decreased with time, but was still higher than that in the control waters. Under the actinic light of 17 micromol x m(-2) x s(-1) PPFD, the effective quantum yield (DeltaFv'/Fm') of seedling leaves on the 60th day in the waters with turbidity of 30 NTU, 60 NTU, and 90 NTU increased by 48.9%, 36.8%, and 17.2% (P < 0.01), and the relative electron transport rate (rETR) increased by 56.7%, 42.2%, and 21.4% (P < 0.01), respectively, compared with those on the 30th day. However, under the actinic light of 104 micromol x m(-2) s(-1) PPFD, the DeltaFv'/Fm', qp, and rETR on the 60th day decreased significantly, and the heat dissipation capability (qN) also reduced evidently. All the results suggested that the H. verticillata seedlings in turbid waters could adapt to low light environment, but their leaves were easy to be damaged under high light intensity. Therefore, it would be possible to introduce H. verticillata seedlings in shallow turbid waters.

  3. Dynamic Response of Plant Chlorophyll Fluorescence to Light, Water and Nutrient Availability

    NASA Astrophysics Data System (ADS)

    Cendrero Mateo, M. D. P.; Moran, S. M.; Porcar-Castell, A.; Carmo-Silva, A. E.; Papuga, S. A.; Matveeva, M.; Wieneke, S.; Rascher, U.

    2014-12-01

    Photosynthesis is the most important exchange process of CO2 between the atmosphere and the land-surface. Spatial and temporal patterns of photosynthesis depend on dynamic plant-specific adaptation strategies to highly variable environmental conditions e.g. light, water, and nutrient availability. Chlorophyll fluorescence (ChF) has been proposed as a direct indicator of photosynthesis, and several studies have demonstrated its relationship with vegetation functioning at leaf and canopy level. In this study, two 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) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? The results of this study indicated that when the differences between treatments (water or nitrogen) drive the relationship between photosynthesis and ChF, ChF has a direct relationship with photosynthesis. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a simple linear function due to the complex physiological relation between photosynthesis and ChF. Our study showed that at times in the season when nitrogen was sufficient and photosynthesis was highest, ChF decreased because these two processes compete for available energy. The results from this study demonstrated that ChF is a reliable indicator of plant stress and has great potential as a tool for better understand where, when, and how CO2 is exchanged between the land and atmosphere.

  4. PhotoSpec - Ground-based Remote Sensing of Solar-Induced Chlorophyll Fluorescence: First Results

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    Solar-Induced Chlorophyll Fluorescence (SIF) emitted from vegetation can be used as a proxy for photosynthetic activity and is 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 from environmental conditions, water stress, or radiation. We have developed a novel ground-based spectrometer system for measuring SIF from natural ecosystems. 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, and also includes a commercial photosynthetic active radiation (PAR) sensor. The spectrometers cover a SIF retrieval wavelength range at high spectral resolution (670 - 780 nm, 0.1 nm FWHM), and also provide moderate resolution spectra (400 - 800 nm, 1.5 nm FWHM) to retrieve vegetation indices and the photochemical reflectance index (PRI). We report on results of the first continuous field measurements of this novel system at Stunt Ranch Santa Monica Mountains UC Reserve, where the PhotoSpec instrument was monitoring SIF of four native Californian shrubland species with different adaptations to seasonal summer drought. We report on the correlation with CO2 fluxes over both the growing season and the hot summer period in 2016. We also show detailed measurements of the diurnal cycle of the SIF signal of single broad leaves, as well as dark-light transitions, under controlled experimental conditions. In addition to demonstrating the instrumental set-up, retrieval algorithm, and instrument performance, our results illustrate that SIF measurements at the leaf to ecosystem scale are needed to understand and interpret the SIF signals retrieved at larger scales.

  5. Energetics of Photosystem II charge recombination in Acaryochloris marina studied by thermoluminescence and flash-induced chlorophyll fluorescence measurements.

    PubMed

    Cser, Krisztián; Deák, Zsuzsanna; Telfer, Alison; Barber, James; Vass, Imre

    2008-01-01

    We studied the charge recombination characteristics of Photosystem II (PSII) redox components in whole cells of the chlorophyll (Chl) d-dominated cyanobacterium, Acaryochloris marina, by flash-induced chlorophyll fluorescence and thermoluminescence measurements. Flash-induced chlorophyll fluorescence decay was retarded in the mus and ms time ranges and accelerated in the s time range in Acaryochloris marina relative to that in the Chl a-containing cyanobacterium, Synechocystis PCC 6803. In the presence of 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, which blocks the Q(B) site, the relaxation of fluorescence decay arising from S(2)Q(A)(-) recombination was somewhat faster in Acaryochloris marina than in Synechocystis PCC 6803. Thermoluminescence intensity of the so called B band, arising from the recombination of the S(2)Q(B)(-) charge separated state, was enhanced significantly (2.5 fold) on the basis of equal amounts of PSII in Acaryochloris marina as compared with Synechocystis 6803. Our data show that the energetics of charge recombination is modified in Acaryochloris marina leading to a approximately 15 meV decrease of the free energy gap between the Q(A) and Q(B) acceptors. In addition, the total free energy gap between the ground state and the excited state of the reaction center chlorophyll is at least approximately 25-30 meV smaller in Acaryochloris marina, suggesting that the primary donor species cannot consist entirely of Chl a in Acaryochloris marina, and there is a contribution from Chl d as well.

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

    PubMed

    Liu, Xinjie; Liu, Liangyun; Hu, Jiaochan; Du, Shanshan

    2017-05-16

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

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

    PubMed Central

    Liu, Xinjie; Liu, Liangyun; Hu, Jiaochan; Du, Shanshan

    2017-01-01

    The measurement of solar-induced chlorophyll fluorescence (SIF) is a new tool for estimating gross primary production (GPP). Continuous tower-based spectral observations together with flux measurements are an efficient way of linking the SIF to the GPP. Compared to conical observations, hemispherical observations made with cosine-corrected foreoptic have a much larger field of view and can better match the footprint of the tower-based flux measurements. However, estimating the equivalent radiation transfer path length (ERTPL) for hemispherical observations is more complex than for conical observations and this is a key problem that needs to be addressed before accurate retrieval of SIF can be made. In this paper, we first modeled the footprint of hemispherical spectral measurements and found that, under convective conditions with light winds, 90% of the total radiation came from an FOV of width 72°, which in turn covered 75.68% of the source area of the flux measurements. In contrast, conical spectral observations covered only 1.93% of the flux footprint. Secondly, using theoretical considerations, we modeled the ERTPL of the hemispherical spectral observations made with cosine-corrected foreoptic and found that the ERTPL was approximately equal to twice the sensor height above the canopy. Finally, the modeled ERTPL was evaluated using a simulated dataset. The ERTPL calculated using the simulated data was about 1.89 times the sensor’s height above the target surface, which was quite close to the results for the modeled ERTPL. Furthermore, the SIF retrieved from atmospherically corrected spectra using the modeled ERTPL fitted well with the reference values, giving a relative root mean square error of 18.22%. These results show that the modeled ERTPL was reasonable and that this method is applicable to tower-based hemispherical observations of SIF. PMID:28509843

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

    PubMed Central

    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 basically same

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

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

    2016-05-27

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  13. A linear method for the retrieval of sun-induced chlorophyll fluorescence from GOME-2 and SCIAMACHY data

    NASA Astrophysics Data System (ADS)

    Köhler, Philipp; Guanter, Luis; Joiner, Joanna

    2015-04-01

    Global retrievals of near-infrared sun-induced chlorophyll fluorescence (SIF) have been achieved in the last several years by means of space-borne atmospheric spectrometers. SIF is an electromagnetic signal emitted by the chlorophyll-a of photosynthetically active vegetation in the 650-850 nm spectral range. It represents a part of the excess energy during the process of photosynthesis and provides a measure of photosynthetic activity. The key challenge to retrieve SIF from space is to isolate the signal from the about 100 times more intense reflected solar radiation in the measured top of atmosphere (TOA) radiance spectrum. Nevertheless, it has been demonstrated that a number of satellite sensors provide the necessary spectral and radiometric performance to evaluate the in-filling of solar Fraunhofer lines and/or atmospheric absorption features by SIF. We will present recent developments for the retrieval of SIF from medium spectral resolution space-borne spectrometers such as the Global Ozone Monitoring Experiment (GOME-2) and the Scanning Imaging Absorption SpectroMeter for Atmospheric ChartographY (SCIAMACHY). Building upon the previous work by Joiner et al. 2013, our approach solves existing issues in the retrieval such as the non-linearity of the forward model and the arbitrary selection of the number of free parameters. In particular, we use a backward elimination algorithm 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 from real spectra from GOME-2 and for the first time, from SCIAMACHY. We are able to present a time series of GOME-2 SIF results covering the 2007-2011 time period and SCIAMACHY SIF results between 2003-2011. This represents an almost one decade long record of global SIF. We

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

    NASA Astrophysics Data System (ADS)

    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

  15. Optimal estimator for tomographic fluorescence lifetime multiplexing

    PubMed Central

    Hou, Steven S.; Bacskai, Brian J.; Kumar, Anand T. N.

    2016-01-01

    We use the model resolution matrix to analytically derive an optimal Bayesian estimator for multiparameter inverse problems that simultaneously minimizes inter-parameter cross talk and the total reconstruction error. Application of this estimator to time-domain diffuse fluorescence imaging shows that the optimal estimator for lifetime multiplexing is identical to a previously developed asymptotic time-domain (ATD) approach, except for the inclusion of a diagonal regularization term containing decay amplitude uncertainties. We show that, while the optimal estimator and ATD provide zero cross talk, the optimal estimator provides lower reconstruction error, while ATD results in superior relative quantitation. The framework presented here is generally applicable to other multiplexing problems where the simultaneous and accurate relative quantitation of multiple parameters is of interest. PMID:27192234

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

    NASA Technical Reports Server (NTRS)

    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

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

    NASA Technical Reports Server (NTRS)

    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

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

    NASA Astrophysics Data System (ADS)

    Zavoruev, Valerii; Zavorueva, Elena

    2003-04-01

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

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

    PubMed

    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

  20. LAI and chlorophyll estimation for a heterogeneous grassland using hyperspectral measurements

    NASA Astrophysics Data System (ADS)

    Darvishzadeh, Roshanak; Skidmore, Andrew; Schlerf, Martin; Atzberger, Clement; Corsi, Fabio; Cho, Moses

    The study shows that leaf area index (LAI), leaf chlorophyll content (LCC) and canopy chlorophyll content (CCC) can be mapped in a heterogeneous Mediterranean grassland from canopy spectral reflectance measurements. Canopy spectral measurements were made in the field using a GER 3700 spectroradiometer, along with concomitant in situ measurements of LAI and LCC. We tested the utility of univariate techniques involving narrow band vegetation indices and the red edge inflection point, as well as multivariate calibration techniques, including stepwise multiple linear regression and partial least squares regression. Among the various investigated models, CCC was estimated with the highest accuracy ( Rcv2=0.74, nRMSE=0.35). All methods failed to estimate LCC ( Rcv2≤0.40), while LAI was estimated with intermediate accuracy ( Rcv2 values ranged from 0.49 to 0.69). Compared with narrow band indices and red edge inflection point, stepwise multiple linear regression generally improved the estimation of LAI. The estimations were further improved when partial least squares regression was used. When a subset of wavelengths was analyzed, it was found that partial least squares regression had reduced the error in the retrieved parameters. The results of the study highlight the significance of multivariate techniques, such as partial least squares regression, rather than univariate methods such as vegetation indices in estimating heterogeneous grass canopy characteristics.

  1. Estimating a carbon/chlorophyll ratio in nannoplankton (Creteil Lake, S-E Paris, France)

    SciTech Connect

    Garnier, J.; Benest, D. ); Blanc, P. )

    1989-08-01

    The phytoplankton biomass of the Creteil Lake was characterized through 47 paired measurements of particulate organic carbon and chlorophyll. When determining the transfers of organic carbon in the lake, the need to convert the phytoplankton biomass into carbon units led to the estimation of a carbon to chlorophyll ratio using regression analyses. An average C:Chl ratio of 80 was found. C:Chl has been found to be highly variable but the value commonly used is C:Chl = 40. In Creteil Lake, the high C:Chl value would characterize the nannoplankton that dominated in the lake. No general conversion factor apparently exists for natural populations; thus, more studies may be necessary for a better knowledge of the carbon budget in lakes.

  2. Simulations show that a small part of variable chlorophyll a fluorescence originates in photosystem I and contributes to overall fluorescence rise.

    PubMed

    Lazár, Dušan

    2013-10-21

    Photosystem I (PSI) is generally assumed not to emit variable chlorophyll (Chl) fluorescence during light-induced Chl fluorescence rise (FLR), which occurs in a time window upto 1s under high intensity of excitation light. Therefore, the measured FLR and its changes caused by any treatment are usually interpreted by changes only in photosystem II (PSII) fluorescence. But examples can be found in the literature indicating that PSI can emit variable Chl fluorescence at least under certain conditions. As it is impossible to determine the PSI variable Chl fluorescence in vivo solely based on experiments, a way to explore a possible existence of PSI variable Chl fluorescence is to construct a mathematical model of reactions occurring inside and around PSI and to simulate a hypothetical FLR. Based on our present knowledge about the function of PSI, a detailed model describing reactions occurring inside and around PSI was constructed and used for the simulation of FLR originating exclusively in PSI. These simulations show that PSI, in principle, can emit variable Chl fluorescence. Several in silico experiments are performed showing the effect of particular reactions on the FLR. The theoretical PSI variable Chl fluorescence is also compared with theoretical variable fluorescence originating in PSII simulated on the basis of an improved model of PSII showing that variable fluorescence originating in PSI can be as high as 8-17% of overall maximal fluorescence signal originating in both photosystems. The overall FLR obtained as a sum of the simulated FLRs originating in PSI and PSII shows a peak which is similar to an H-peak measured with certain type of samples. We suggest that new experiments be planned to prove the new concept of variable PSI fluorescence. © 2013 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2016-06-21

    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.

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

    PubMed Central

    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

  5. Linking leaf chlorophyll fluorescence properties to physiological responses for detection of salt and drought stress in coastal plant species.

    PubMed

    Naumann, Julie C; Young, Donald R; Anderson, John E

    2007-11-01

    Effects of salinity and drought on physiology and chlorophyll fluorescence were used to evaluate stress in two coastal plants, Myrica cerifera (L.) and Phragmites australis (Cav.) Trin. ex Steud. Drought and salinity stress were induced and measurements of stomatal conductance, photosynthesis, xylem pressure potential (psi) and fluorescence were conducted following treatment. The onset of stress began at 2 g l(-1) for M. cerifera, and 5 g l(-1) for P. australis, as seen by significant decreases in physiological measurements. Despite the physiological effects of salinity, there was no significant difference in dark-adapted fluorescence (F(v)/F(m), where F(m) is the maximal fluorescence in dark-adapted leaves) for either species at any salinity level. Significant decreases in the light-adapted measurement Delta F/F'(m) (F'(m) is maximal fluorescence in light-adapted leaves) occurred at 10 g l(-1) in M. cerifera and P. australis, days before visible stress was evident. The quantum yield of xanthophyll-regulated thermal energy dissipation (Phi(NPQ), where NPQ is non-photochemical quenching of chlorophyll fluorescence) increased with decreasing Delta F/F'(m). Drought studies showed similar results, with significant decreases in physiological measurements occurring by day 2 in M. cerifera and day 4 in P. australis. Differences in Delta F/F'(m) were seen by day 5 for both species, whereas F(v)/F(m) showed no indication of stress, despite apparent visible signs. Xanthophyll-cycle-dependent energy dissipation may be the underlying mechanism in protecting photosystem II from excess energy in salinity- and drought-treated plants.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Chlorophyll fluorescence (CF) results from non-photochemical quenching during plant photosynthesis under excessive radiation. We explore the relationship between gross primary productivity (GPP) and CF using a process ecosystem model, which separates a vegetation canopy into sunlit and shaded leaf groups and simulates the total canopy GPP as the sum of sunlit and shaded leaf GPP. Using GOME-2 and GOSAT data acquired in 2010 over the global land surface, we found that measured CF signals gridded in 1 degree resolution are well correlated with simulated total GPP and its sunlit and shaded components, but the correlation coefficients (R) are largest for the sunlit GPP and smallest for shaded GPP. The seasonal R2 values vary from 0.57 to 0.74, 0.58 to 0.71, and 0.48 to 0.56 for sunlit, total and shaded GPP, respectively. The significance levels for these correlations are all greater than p<0.01. Averaged over the globe, the total simulated shaded GPP is 39% of the total GPP. Theoretically, CF from vegetation comes mostly from sunlit leaves. The significant correlation between measured canopy-level CF and the shaded GPP is likely due to the correlation between shaded and sunlit GPP as both increase with leaf area index. Our simulation confirms the validity of using canopy-level CF measurements to assess the total GPP as the first approximation, although these measurements are a consistently better indicator of sunlit GPP than total GPP. In previous studies, the R2 values for the correlation between CF and total GPP were found to range from 0.76 to 0.88, 0.56 to 0.78, and 0.57 to 0.77 for MPI-BGC, MODIS and CASA model results, respectively. These values are similar or larger than those for sunlit GPP simulated in our study, but are considerably larger than those for total GPP in our study because the correlation for total GPP is contaminated by the inclusion of shaded GPP. All these three models use canopy total light use efficiency without considering the differences

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

    PubMed

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

    2010-01-01

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

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

    NASA Technical Reports Server (NTRS)

    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

  9. Estimation of time averages from irregularly spaced observations - With application to coastal zone color scanner estimates of chlorophyll concentration

    NASA Technical Reports Server (NTRS)

    Chelton, Dudley B.; Schlax, Michael G.

    1991-01-01

    The sampling error of an arbitrary linear estimate of a time-averaged quantity constructed from a time series of irregularly spaced observations at a fixed located is quantified through a formalism. The method is applied to satellite observations of chlorophyll from the coastal zone color scanner. The two specific linear estimates under consideration are the composite average formed from the simple average of all observations within the averaging period and the optimal estimate formed by minimizing the mean squared error of the temporal average based on all the observations in the time series. The resulting suboptimal estimates are shown to be more accurate than composite averages. Suboptimal estimates are also found to be nearly as accurate as optimal estimates using the correct signal and measurement error variances and correlation functions for realistic ranges of these parameters, which makes it a viable practical alternative to the composite average method generally employed at present.

  10. Hyperspectral indices for leaf and pixel chlorophyll estimation in open-canopy tree

    NASA Astrophysics Data System (ADS)

    Zhao, Jin; Chen, Xi; Japper, Guli; Chang, Huaitian; Ma, Zhongguo; Duan, Yuanbin

    2007-06-01

    In this paper, the goal is to found indices best for Cab estimation with leaves and heperion pixels. There are several indices chosen, which showed best results for Cab estimation at both leaf and canopy levels in other studies. Forty-eight typical leaves were sampled in middle and lower reach of the Tarim River, Xinjiang, China. Leaf reflectance and Chlorophyll of leaves collected. Result demonstrated that Indices such as red edge and derivative indices R750/R710, R740/R720, (R734-R747)/(R715+R720), Blog(1/R737), D715/D705,(R734-R747)/(R715+R726), (R694-R680)/(R732-R760) were shown to be the good indicators for Cab estimation at leaf. Hyperion data were acquired for Aqike section in the middle reaches of the Tarim River in Nine 28, 2006. Field data were collected at same day to coincide with the Hyperion, including Chlorophyll of each tree, LAI, green vegetation cover. LAI derived from scanopy 2006. Inventory field plots were 120m×120m quadrants, and Chlorophyll of pixel is deduced from field data of 360 trees. Generally good results are found for Cab estimation at pixel level with indices such as, (R734-R747)/(R715+R726), Blog(1/R737), (R694-R680)/(R732-R760), TCARI, TCARI/OSAVI, MCARI/OSAVI and so on. It was found that (R734-R747)/(R715+R720), Blog(1/R737), D715/D705, (R734-R747)/(R715+R726), (R694-R680)/(R732-R760),R740/R720 were successfully test on leaves and piexls. On the other hand, the "modified" indices (TCARI, MCAVI, TCARI/OSAVI, MCARI/OSAVI) already give good results at the piexl level.

  11. Thermotolerance of apple tree leaves probed by chlorophyll a fluorescence and modulated 820 nm reflection during seasonal shift.

    PubMed

    Duan, Ying; Zhang, Mengxia; Gao, Jin; Li, Pengmin; Goltsev, Vasilij; Ma, Fengwang

    2015-11-01

    During the seasonal shift from June to August, air temperatures increase. To explore how apple trees improve their thermotolerance during this shift, we examined the photochemical reaction capacity of apple tree leaves by simultaneous measurement of prompt chlorophyll fluorescence, delayed chlorophyll fluorescence, and modulated 820 nm reflection at varying temperatures. It was found that the reaction centers and antennae of photosystem II (PSII) and photosystem I (PSI), the donor side of PSII, the electron transfer capacity from QA to QB, and the reoxidation capacity of plastoquinol were all sensitive to heat stress, particularly in June. As the season shifted, apple tree leaves improved in thermotolerance. Interestingly, the acclimation to seasonal shift enhanced the thermotolerance of PSII and PSI reaction centers more than that of their antennae, and the activity of PSII more than that of PSI. This may be a strategy for plant adaptation to changes in environmental temperatures. In addition, results from prompt and delayed fluorescence, as well as modulated 820 nm reflection corroborate each other. We suggest that the simultaneous measurement of the three independent signals may provide more information on thermal acclimation mechanisms of photochemical reactions in plant leaves.

  12. Primary sites of ozone-induced perturbations of photosynthesis in leaves: identification and characterization in Phaseolus vulgaris using high resolution chlorophyll fluorescence imaging.

    PubMed

    Leipner, J; Oxborough, K; Baker, N R

    2001-08-01

    High resolution imaging of chlorophyll a fluorescence was used to identify the sites at which ozone initially induces perturbations of photosynthesis in leaves of Phaseolus vulgaris. Leaves were exposed to 250 and 500 nmol mol(-1) ozone at a photosynthetically active photon flux density of 300 micromol m(-2) s(-1) for 3 h. Images of fluorescence parameters indicated that large decreases in both the maximum and operating quantum efficiencies of photosystem II had occurred in cells adjacent to stomata in the upper, but not lower, leaf surfaces. However, this treatment did not produce any significant changes in the maximum or operating quantum efficiencies of photosystem II in the leaves when estimated from fluorescence parameters measured with a conventional, integrating fluorometer. The localized decreases in photosystem II photochemical efficiencies were accompanied by an increase in the minimal fluorescence level, which is indicative of photoinactivation of photosystem II complexes and a decrease in stomatal conductance. Perturbations of photochemical efficiencies were not observed in cells associated with all of the stomata on the upper leaf surface or within cells distant from the upper leaf surface. It is concluded that ozone penetrates the leaf through stomata and initially damages only cells close to stomatal pores.

  13. 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.

    PubMed

    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.

  14. Spatial distribution and seasonal variability of chlorophyll-a concentration in the Azov Sea turbid waters by means of remote sensing and continuous fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Saprygin, V. V.

    2011-12-01

    The goal of this study was to apply continuous fluorometric and remote estimation of chlorophyll-a concentration (Cchl) techniques to complex turbid waters of Azov Sea and explore Cchl temporal variation and spatial pattern. Azov Sea is the shallowest sea in the world with maximum depth below 15 m. Its maximum salinity is about 14%; total suspended solids and chlorophyll-a concentrations reach 120 [tex]g m^{-3}[/tex] and 100 [tex]mg m^{-3}[/tex] respectively in Taganrog Bay, daily production varies up to 3.5 [tex]gC_{org} m^{-3}[/tex]. Chlorophyll-a concentrations were measured in 2008-2010 year-round spectrophotometrically, 446 water samples were taken to calibrate fluorometerical and remote sensing data. The highest recorded concentration was 149.3, the lowest - 0.3 [tex]mg m^{-3}[/tex]. Continuous-flow fluorometer was applied in the course of 3 expeditions to Taganrog Bay to measure chlorophyll-a fluorescence (Fchl) each 30 meters along the ship path. Two-cuvette fluorometer was used to discount the influence of dissolved organic matter. Fchl measurements were calibrated and Cchl profiles derieved to estimate Cchl spatial heterogeneity in close scale. Fchl measurements were also made during moorings each 6 seconds to estimate temporal Cchl variability. Recently published algorithm based on reflectance in the red and the near-infrared (NIR) spectral regions was applied to MERIS data for the remote estimation of Cchl. Taking in account fluorometric Cchl spatial heterogeneity estimation, the algorithm for culling the outliers in Cchl fields derived from satellite data was developed. 74 images were processed to Cchl maps and then averaged monthly. Consequently, Cchl spatial distribution and seasonal variability were studied. Spectrophotometric, flourumetric measurements and values obtained by NIR-red algorithm showed strong correlation in turbid Case II waters of Azov Sea. Fluorometric and remote measurements showed high Cchl variations in short and long terms

  15. [A Three Band Chlorophyll-a Concentration Estimation Model Based on GOCI Imagery].

    PubMed

    Guo, Yu-long; Li, Yun-mei; Li, Yuan; Lü, Heng; Liu, Ge; Wang, Xu-dong; Zhang, Si-min

    2015-09-01

    A GOCI-based three band model is proposed for chlorophyll-a concentration estimation based on the classical three band model. The model was built based on 289 in-situ measured chlorophyll-a concentration and hyperspectral spectrums-simulated GOCI spectrums, and was compared with MERIS-based three band model and GOCI band ratio model. At last, the model was validated using several GOCI images and an independent in-situ sampling dataset. The results showed that: (1) For the current dataset, the ratio of aph (680) and aph (660) was relatively stable. (2) The GOCI-based three band algorithm had a similar performance with MERIS-based three band algorithm in the modeling dataset. The R2 value of the GOCI-based three band model was 0. 809, which was a little lower than that of the MERIS-based three band model (R2 = 0. 820), but was obviously higher than that of GOCI band ratio model (R2 = 0. 450). (3) The performance of GOCI-based three band model in the validation dataset was similar with that in the modeling dataset, which was close to that of the MERIS-based three band model, and significantly better than that of GOCI band ratio model. (4) The GOCI image data validation indicated that GOCI band ratio model would clearly underestimate chlorophyll-a concentration in Taihu Lake. The spatial difference of chlorophyll-a concentration that yielded by the band ratio model was not clear. Compared with the widely used band ratio algorithm, the GOCI-based three band algorithm has higher stability, better accuracy, and stronger potential in application.

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

    PubMed

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

    2013-09-01

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

  17. Seasonal and intraspecific variability of chlorophyll fluorescence, pigmentation and growth of Pinus ponderosa subjected to elevated CO{sub 2}

    SciTech Connect

    Houpis, J.L.J.; Anschel, D.; Pushnik, J.C.; Demaree, R.S.; Anderson, P.D.

    1994-12-01

    Atmospheric CO{sub 2}2 is expected to double in the next century, and these increases will have substantial impact on forest ecosystems. However, the database on the effects of elevated CO{sub 2} on forests is limited, and the extent of intraspecific variability remains unknown. We are investigating the effects of elevated CO{sub 2} on the intraspecific variability of quantum yield (as measured through chlorophyll fluorescence Fv/Fm ratio) and pigmentation, and how these are correlated to variability in growth. Four-year-old Pinus ponderosa seedlings were obtained from nine different sources across California. These seedlings were grown in standard outdoor exposure chambers for sixteen months at either ambient levels of CO{sub 2}, ambient+175ppm CO{sub 2}, or ambient+350ppm CO{sub 2}. The seedlings were periodically measured for growth, pigmentation, and chlorophyll fluorescence. The results showed a variable growth response of the nine sources during all measurement periods. Increasing CO{sub 2} resulted in a decrease in Fv/Fm among sources ranging from {minus}2.1% to {minus}23.2% in February, and 3.1% to {minus}12.5% in June. The source that had the best growth throughout the study, also had a minimal reduction in quantum yield (Fv/Fm) in the presence of elevated CO{sub 2}. For the seedlings of fastest growing sources, the correspondence between total growth and chlorophyll fluorescence was strongest during the February measurement period. Our results also showed a significant reduction in pigmentation due to increased CO{sub 2}. There are at least three explanations for the different responses during each measurement periods. First, the trees could be adapting favorably to increasing CO{sub 2}. Secondly, 1993 needles could be under less physiological stress than the current year needles. Third, there is a seasonal effect dependent upon temperature or light which is influencing the Fv/Fm ratio and pigmentation.

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

    PubMed

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

    2011-09-01

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

  19. An Exact One-Dimensional Solution to the Problem of Chlorophyll Fluorescence from the Ocean,

    DTIC Science & Technology

    1982-03-03

    N00014-80-C-0113. I I I I I Table I. Scattering (BS), absorption (0 a), and total extinction co- efficients (OT) for the water, hydrosol , and chlorophyll... Hydrosol Chlorophyll a (m- 1 ) (m- 1 ) (m-l/(mg-m3 )) Oa 3.802+ 9.10-4 1.00-2 ;0 0.826 OS 1.20-2 3.00-2 - OT 5.00-2 3.09-2 1.00-2 Pa 2.20-2 8.50-4...means that the number is multipied by 10-N s’W U 4 %IV vs% I.."% ’d X(nm) HDo(w/ m 2 - nm) water hydrosol chlorophyll a 0a 2.57-2 5.70-4 1.80-2 500

  20. FluorWPS: A Monte Carlo ray-tracing model to compute sun-induced chlorophyll fluorescence of three-dimensional canopy

    USDA-ARS?s Scientific Manuscript database

    A model to simulate radiative transfer (RT) of sun-induced chlorophyll fluorescence (SIF) of three-dimensional (3-D) canopy, FluorWPS, was proposed and evaluated. The inclusion of fluorescence excitation was implemented with the ‘weight reduction’ and ‘photon spread’ concepts based on Monte Carlo ra...

  1. Heavy metal stress detection and monitoring via LED-induced chlorophyll fluorescence analysis of Zea mays L. seedlings aimed at polluted soil phytoremediation

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    Chlorophyll fluorescence spectroscopy is employed to detect and study the time evolution of metal stress of Zea mays L. seedlings aiming polluted soil phytoremediation. The chlorophyll fluorescence spectra of intact leaves are analyzed using 405 nm LED excitation. Red (Fr) and far-red (FFr) emissions around 685 nm and 735 nm, respectively, are examined as a function of the heavy metal concentration. The fluorescence ratio Fr/FFr was employed to monitor the effect of heavy metal upon the physiological state of the plants before signs of visual stress became apparent. The chlorophyll fluorescence analysis permitted detection and evaluation of the damage caused by heavy metal soil contamination in the early stages of the plants growing process, which is not feasible using conventional in vitro spectral analysis.

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

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

    PubMed

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

    2014-02-01

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

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

    PubMed

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

    2017-01-05

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

  5. Relationships between the photochemical reflectance index (PRI) and chlorophyll fluorescence parameters and plant pigment indices at different leaf growth stages.

    PubMed

    Rahimzadeh-Bajgiran, Parinaz; Munehiro, Masashi; Omasa, Kenji

    2012-09-01

    This study aimed to evaluate the photochemical reflectance index (PRI) for assessing plant photosynthetic performance throughout the plant life cycle. The relationships between PRI, chlorophyll fluorescence parameters, and leaf pigment indices in Solanum melongena L. (aubergine; eggplant) were studied using photosynthetic induction curves both in short-term (diurnal) and long-term (seasonal) periods under different light intensities. We found good correlations between PRI/non-photochemical quenching (NPQ) and PRI/electron transport rate (ETR) in the short term at the same site of a single leaf but these relationships did not hold throughout the life of the plant. In general, changes in PRI owing to NPQ or ETR variations in the short term were <20 % of those that occurred with leaf aging. Results also showed that PRI was highly correlated to plant pigments, especially chlorophyll indices measured by spectral reflectance. Moreover, relationships of steady-state PRI/ETR and steady-state PRI/photochemical yield of photosystem II (Φ(PSII)) measured at uniform light intensity at different life stages proved that overall photosynthesis capacity and steady-state PRI were better correlated through chlorophyll content than NPQ and xanthophylls. The calibrated PRI index accommodated these pigments effects and gave better correlation with NPQ and ETR than PRI. Further studies of PRI indices based on pigments other than xanthophylls, and studies on PRI mechanisms in different species are recommended.

  6. Sunlight induced chlorophyll fluorescence in the near-infrared spectral region in natural waters: Interpretation of the narrow reflectance peak around 761 nm

    NASA Astrophysics Data System (ADS)

    Lu, Yingcheng; Li, Linhai; Hu, Chuanmin; Li, Lin; Zhang, Minwei; Sun, Shaojie; Lv, Chunguang

    2016-07-01

    Sunlight induced chlorophyll a fluorescence (SICF) can be used as a probe to estimate chlorophyll a concentrations (Chl) and infer phytoplankton physiology. SICF at ˜685 nm has been widely applied to studies of natural waters. SICF around 740 nm has been demonstrated to cause a narrow reflectance peak at ˜761 nm in the reflectance spectra of terrestrial vegetation. This narrow peak has also been observed in the reflectance spectra of natural waters, but its mechanism and applications have not yet been investigated and it has often been treated as measurement artifacts. In this study, we aimed to interpret this reflectance peak at ˜761 nm and discuss its potential applications for remote monitoring of natural waters. A derivative analysis of the spectral reflectance suggests that the 761 nm peak is due to SICF. It was also found that the fluorescence line height (FLH) at 761 nm significantly and linearly correlates with Chl. FLH(761 nm) showed a tighter relationship with Chl than the relationship between FLH(˜685 nm) and Chl mainly due to weaker perturbations by nonalgal materials around 761 nm. While it is not conclusive, a combination of FLH(761 nm) and FLH(˜685 nm) might have some potentials to discriminate cyanobacteria from other phytoplankton due to their different fluorescence responses at the two wavelengths. It was further found that reflectance spectra with a 5 nm spectral resolution are adequate to capture the spectral SICF feature at ˜761 nm. These preliminary results suggest that FLH(761 nm) need to be explored more for future applications in optically complex coastal and inland waters.

  7. The fast and slow kinetics of chlorophyll a fluorescence induction in plants, algae and cyanobacteria: a viewpoint.

    PubMed

    Papageorgiou, George C; Tsimilli-Michael, Merope; Stamatakis, Kostas

    2007-01-01

    The light-induced/dark-reversible changes in the chlorophyll (Chl) a fluorescence of photosynthetic cells and membranes in the mus-to-several min time window (fluorescence induction, FI; or Kautsky transient) reflect quantum yield changes (quenching/de-quenching) as well as changes in the number of Chls a in photosystem II (PS II; state transitions). Both relate to excitation trapping in PS II and the ensuing photosynthetic electron transport (PSET), and to secondary PSET effects, such as ion translocation across thylakoid membranes and filling or depletion of post-PS II and post-PS I pools of metabolites. In addition, high actinic light doses may depress Chl a fluorescence irreversibly (photoinhibitory lowering; q(I)). FI has been studied quite extensively in plants an algae (less so in cyanobacteria) as it affords a low resolution panoramic view of the photosynthesis process. Total FI comprises two transients, a fast initial (OPS; for Origin, Peak, Steady state) and a second slower transient (SMT; for Steady state, Maximum, Terminal state), whose details are characteristically different in eukaryotic (plants and algae) and prokaryotic (cyanobacteria) oxygenic photosynthetic organisms. In the former, maximal fluorescence output occurs at peak P, with peak M lying much lower or being absent, in which case the PSMT phases are replaced by a monotonous PT fluorescence decay. In contrast, in phycobilisome (PBS)-containing cyanobacteria maximal fluorescence occurs at M which lies much higher than peak P. It will be argued that this difference is caused by a fluorescence lowering trend (state 1 --> 2 transition) that dominates the FI pattern of plants and algae, and correspondingly by a fluorescence increasing trend (state 2 --> 1 transition) that dominates the FI of PBS-containing cyanobacteria. Characteristically, however, the FI pattern of the PBS-minus cyanobacterium Acaryochloris marina resembles the FI patterns of algae and plants and not of the PBS

  8. Imaging of chlorophyll a fluorescence: theoretical and practical aspects of an emerging technique for the monitoring of photosynthetic performance.

    PubMed

    Oxborough, Kevin

    2004-05-01

    The development of chlorophyll (Chl) a fluorescence imaging systems has greatly increased the versatility of Chl a fluorometry as a non-invasive technique for the investigation of photosynthesis in plants and algae. For example, systems that image at the microscopic level have made it possible to measure PSII photochemical efficiencies from chloroplasts within intact leaves and from individual algal cells within mixed populations, while systems that image over much larger areas have been used to investigate heterogeneous patterns of photosynthetic performance across leaves and in screening programmes that image tens or even hundreds of plants simultaneously. In addition, it is now practical to use fluorescence imaging systems as real-time, multi-channel fluorometers, which can be used to record continuous fluorescence traces from multiple leaves, plants, or algal cells. This paper discusses some of the theoretical and practical issues associated with the imaging of Chl a fluorescence and with Chl a fluorometry in general. This discussion includes a review of the most commonly used Chl a fluorescence parameters.

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

    PubMed

    Vredenberg, Wim; Pavlovič, Andrej

    2013-02-15

    This paper describes experiments on transient changes in chlorophyll a fluorescence in traps of the carnivorous plant Venus flytrap (Dionaea muscipula) that occur in association with mechanical stimulation of trigger hairs and propagation of action potentials (APs). The experiments show the following reproducible effects of APs on the fluorescence induction (Kautsky-, or OJIPSMT curve) in a 100 s low intensity light pulse (i) no change in the OJ phase attributed to release of photochemical quenching, (ii) a small enhancement, if at all of increase in the thermal JIP phase, (iii) a two- to threefold deceleration of the fluorescence decline (quenching) during the PSMT phase in the 2-100 s time range, and (iv) a transient 15-50% increase in variable fluorescence within ~20 s under steady state light condition with, after ~80 s, a 10% undershoot that reverses in several tens of seconds to the original steady state. The results are discussed in terms of a hypothesis that the fluorescence decline during the SMT phase of the Kautsky induction curve, attributed to NPQ, is caused by the Δμ(H+)-driven increase in proton conductance of the CF(o) channel of the ATPase during its activation. A signal-transducing role of Ca(2+) is suggested.

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

    PubMed

    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.

  11. Using Chlorophyll Fluorescence to Assess the Impact of Agriculture on Northern Hemisphere CO2 Seasonality

    NASA Astrophysics Data System (ADS)

    Butterfield, Z.; Keppel-Aleks, G.

    2015-12-01

    The seasonality of carbon dioxide (CO2) concentrations in the northern hemisphere (NH) has increased by up to 50% over the previous five decades. A significant portion of this increase may be explained by enhanced agricultural productivity. The impact that increased crop production has on CO­­2 seasonality is dependent on the fraction of the crop Gross Primary Product (GPP) that occurs during the natural carbon uptake period (CUP). Solar Induced Fluorescence (SIF), an artifact of photosynthesis, can be used to assess GPP directly via remote sensing. New methods for measuring SIF from space provide tools for obtaining GPP data at regional and global levels. We use SIF data from the GOSAT and OCO-2 satellites to obtain observational estimates of the fraction of GPP occurring within the CUP in NH agricultural regions. We compare these fractions with estimates made using crop calendars and inventories and, where available, with CO2 flux data from eddy covariance towers. Our results offer insight into the impact that increased agricultural productivity has on the seasonal amplitude of NH CO2 concentrations.

  12. Linking Leaf Chlorophyll Fluorescence Properties to Physiological Responses for Stress Detection in Coastal Plant Species

    DTIC Science & Technology

    2007-01-01

    conductance, photosynthesis, xylem pressure potential (c) and fluorescence were conducted following treatment. The onset of stress began at 2 g l21 for M...stress were induced and measurements of stomatal conductance, photosynthesis, xylem pressure potential (c) and fluorescence were conducted following...were induced and measurements of stomatal conductance, photosynthesis, xylem pressure potential (c) and fluorescence were conducted following

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

    PubMed

    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.

  14. Identification of nutrient deficiency in maize and tomato plants by in vivo chlorophyll a fluorescence measurements.

    PubMed

    Kalaji, Hazem M; Oukarroum, Abdallah; Alexandrov, Vladimir; Kouzmanova, Margarita; Brestic, Marian; Zivcak, Marek; Samborska, Izabela A; Cetner, Magdalena D; Allakhverdiev, Suleyman I; Goltsev, Vasilij

    2014-08-01

    The impact of some macro (Ca, S, Mg, K, N, P) and micro (Fe) nutrients deficiency on the functioning of the photosynthetic machinery in tomato (Solanum lycopersicum L.) and maize (Zea mays L.) plants grown in hydroponic cultures were investigated. Plants grown on a complete nutrient solution (control) were compared with those grown in a medium, which lacked one of macro- or microelements. The physiological state of the photosynthetic machinery in vivo was analysed after 14-days of deficient condition by the parameters of JIP-test based on fast chlorophyll a fluorescence records. In most of the nutrient-deficient samples, the decrease of photochemical efficiency, increase in non-photochemical dissipation and decrease of the number of active photosystem II (PSII) reaction centres were observed. However, lack of individual nutrients also had nutrient-specific effects on the photochemical processes. In Mg and Ca-deficient plants, the most severe decrease in electron donation by oxygen evolving complex (OEC) was indicated. Sulphur deficiency caused limitation of electron transport beyond PSI, probably due to decrease in the PSI content or activity of PSI electron acceptors; in contrary, Ca deficiency had an opposite effect, where the PSII activity was affected much more than PSI. Despite the fact that clear differences in nutrient deficiency responses between tomato and maize plants were observed, our results indicate that some of presented fluorescence parameters could be used as fluorescence phenotype markers. The principal component analysis of selected JIP-test parameters was presented as a possible species-specific approach to identify/predict the nutrient deficiency using the fast chlorophyll fluorescence records.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  16. O2-dependent electron flow, membrane energization and the mechanism of non-photochemical quenching of chlorophyll fluorescence.

    PubMed

    Schreiber, U; Neubauer, C

    1990-09-01

    Recent progress in chlorophyll fluorescence research is reviewed, with emphasis on separation of photochemical and non-photochemical quenching coefficients (qP and qN) by the 'saturation pulse method'. This is part of an introductory talk at the Wageningen Meeting on 'The use of chlorophyll fluorescence and other non-invasive techniques in plant stress physiology'. The sequence of events is investigated which leads to down-regulation of PS II quantum yield in vivo, expressed in formation of qN. The role of O2-dependent electron flow for ΔpH- and qN-formation is emphasized. Previous conclusions on the rate of 'pseudocyclic' transport are re-evaluated in view of high ascorbate peroxidase activity observed in intact chloroplasts. It is proposed that the combined Mehler-Peroxidase reaction is responsible for most of the qN developed when CO2-assimilation is limited. Dithiothreitol is shown to inhibit part of qN-formation as well as peroxidase-induced electron flow. As to the actual mechanism of non-photochemical quenching, it is demonstrated that quenching is favored by treatments which slow down reactions at the PS II donor side. The same treatments are shown to stimulate charge recombination, as measured via 50 μs luminescence. It is suggested that also in vivo internal thylakoid acidification leads to stimulation of charge recombination, although on a more rapid time scale. A unifying model is proposed, incorporating reaction center and antenna quenching, with primary control of ΔpH at the PS II reaction center, involving radical pair spin transition and charge recombination to the triplet state in a first quenching step. In a second step, triplet excitation is trapped by zeaxanthin (if present) which in its triplet excited state causes additional quenching of singlet excited chlorophyll.

  17. Dead or Alive? Using Membrane Failure and Chlorophyll a Fluorescence to Predict Plant Mortality from Drought1[OPEN

    PubMed Central

    Speckman, Heather N.; Huhn, Bridger J.; Strawn, Rachel N.; Weinig, Cynthia

    2017-01-01

    Climate models predict widespread increases in both drought intensity and duration in the next decades. Although water deficiency is a significant determinant of plant survival, limited understanding of plant responses to extreme drought impedes forecasts of both forest and crop productivity under increasing aridity. Drought induces a suite of physiological responses; however, we lack an accurate mechanistic description of plant response to lethal drought that would improve predictive understanding of mortality under altered climate conditions. Here, proxies for leaf cellular damage, chlorophyll a fluorescence, and electrolyte leakage were directly associated with failure to recover from drought upon rewatering in Brassica rapa (genotype R500) and thus define the exact timing of drought-induced death. We validated our results using a second genotype (imb211) that differs substantially in life history traits. Our study demonstrates that whereas changes in carbon dynamics and water transport are critical indicators of drought stress, they can be unrelated to visible metrics of mortality, i.e. lack of meristematic activity and regrowth. In contrast, membrane failure at the cellular scale is the most proximate cause of death. This hypothesis was corroborated in two gymnosperms (Picea engelmannii and Pinus contorta) that experienced lethal water stress in the field and in laboratory conditions. We suggest that measurement of chlorophyll a fluorescence can be used to operationally define plant death arising from drought, and improved plant characterization can enhance surface model predictions of drought mortality and its consequences to ecosystem services at a global scale. PMID:28710130

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

    PubMed Central

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

    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 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. PMID:24287532

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

    PubMed

    Marques, Marise Conceição; do Nascimento, Clístenes Williams Araújo

    2013-10-05

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

  20. [Effects of groundwater level on chlorophyll fluorescence characteristics of Tamarix hispida in lower reaches of Tarim River].

    PubMed

    Zhu, Cheng-gang; Li, Wei-hong; Ma, Jian-xin; Ma, Xiao-dong

    2010-07-01

    Based on the monitoring data of groundwater level at the typical sections in lower reaches of Tarim River, three survey plots nearby the ecological monitoring wells with groundwater depths > 6 m were selected to investigate the chlorophyll fluorescence characteristics of Tamarix hispida and its photosynthetic activity of PSII under effects of different groundwater depths. With increasing groundwater depth, the chlorophyll fluorescence parameters such as actual photochemical efficiency of PSII in the light (phi(PSII)), electron transport rate (ETR), and photochemistry quenching (q(p)) of T. hispida decreased, while the non-photochemistry quenching (q(N), NPQ) and the yield for dissipation by down-regulation (Y(NPQ)) increased remarkably, and the maximal photochemical efficiency of PSII (Fv/Fm) maintained an optimum value. All the results suggested that the PSII photosynthetic activity of T. hispida under drought stress declined with increasing groundwater depth, and the greater excess energy could result in more risk of photo-inhibition. However, the good adaptability and drought tolerance of T. hispida could make its PSII not seriously damaged, though the drought stress actually existed.

  1. Oceanic primary production 2. Estimation at global scale from satellite (coastal zone color scanner) chlorophyll

    NASA Astrophysics Data System (ADS)

    Antoine, David; André, Jean-Michel; Morel, André

    A fast method has been proposed [Antoine and Morel, this issue] to compute the oceanic primary production from the upper ocean chlorophyll-like pigment concentration, as it can be routinely detected by a spaceborne ocean color sensor. This method is applied here to the monthly global maps of the photosynthetic pigments that were derived from the coastal zone color scanner (CZCS) data archive [Feldman et al., 1989]. The photosynthetically active radiation (PAR) field is computed from the astronomical constant and by using an atmospheric model, thereafter combined with averaged cloud information, derived from the International Satellite Cloud Climatology Project (ISCCP). The aim is to assess the seasonal evolution, as well as the spatial distribution of the photosynthetic carbon fixation within the world ocean and for a ``climatological year,'' to the extent that both the chlorophyll information and the cloud coverage statistics actually are averages obtained over several years. The computed global annual production actually ranges between 36.5 and 45.6 Gt C yr-1 according to the assumption which is made (0.8 or 1) about the ratio of active-to-total pigments (recall that chlorophyll and pheopigments are not radiometrically resolved by CZCS). The relative contributions to the global productivity of the various oceans and zonal belts are examined. By considering the hypotheses needed in such computations, the nature of the data used as inputs, and the results of the sensitivity studies, the global numbers have to be cautiously considered. Improving the reliability of the primary production estimates implies (1) new global data sets allowing a higher temporal resolution and a better coverage, (2) progress in the knowledge of physiological responses of phytoplankton and therefore refinements of the time and space dependent parameterizations of these responses.

  2. Towards a unified approach for remote estimation of chlorophyll-a in both terrestrial vegetation and turbid productive waters

    NASA Astrophysics Data System (ADS)

    dall Olmo, G.; Gitelson, A. A.; Rundquist, D. C.

    2003-12-01

    The photosynthetic pigment chlorophyll-a is an indicator of biomass and productivity of both terrestrial and aquatic ecosystems. Numerous medium specific, independent techniques to extract information on chlorophyll-a concentration from reflectance have been developedŸn. However, the differences and similarities of methods for extracting chlorophyll-a amounts from reflectance spectral data collected over different types of media (e.g. water bodies and plant leaves) have not been compared and generalized. Recently a conceptual model, relating remotely sensed reflectance and pigment content in higher plant leaves has been developed. The model was devised to isolate the absorption coefficient of the pigment of interest from reflectance spectra using three spectral regions. The model allowed accurate estimation of chlorophyll content in leaves and leaf area index in crops. In this study we tested the applicability of the model to retrieve chlorophyll-a concentrations from reflectance spectra of turbid productive waters. We tuned the conceptual model according to the optical characteristics of the aquatic medium, and accurately predicted chlorophyll-a concentrations in water bodies over a wide range of optical conditions (chlorophyll from 7 to 194 mg m-3; total suspended matter from 0.1 to 214 mg L-1; absorption coefficient of dissolved organic matter from 0.7 to 2.3 m-1). Three spectral bands (the red, red edge and near infra-red) were used in the model, which accounted for 94% of the variance (p<0.0001) of chlorophyll-a concentrations measured analytically. In the range of chlorophyll variation from 7 to 194 mg m-3, the root mean square error (RMSE) of chlorophyll-a estimation was less than 11 mg m-3. The model was validated by independent data set yielding a RMSE of chlorophyll-a prediction lower than 13 mg m-3. Our results provide evidence that this technique may be considered as a general solution, independent of the type of medium, for assessing chlorophyll

  3. Using the UFL-8 UV fluorescent LIDAR to collect ground truth data for calibrating MODIS based CDOM, chlorophyll and suspended sediment measurements

    NASA Astrophysics Data System (ADS)

    Zlinszky, A.; Pelevin, V.; Goncharenko, I.; Soloviev, D.; Molnár, G.

    2009-04-01

    Satellite remote sensing of water quality parameters is becoming a routine method in oceanological applications around the world. One of the main difficulties of calibrating satellite images to map water quality parameters is the large number and high spatial coverage of ground truth data needed. The UFL-8 fluorescent LIDAR developed by the Shirshov Oceanological Institute of the Russian Academy of Sciences measures CDOM, chlorophyll and suspended sediment near-surface concentrations optically in situ, on a travelling boat, and so is capable of a large number of widespread measurements very quickly. The registration of the measured values is connected to a GPS, so all measurements are geo-tagged and can be used for interpolating maps of the measured parameters. Since this instrument also has to be calibrated, some water samples have to be collected, but the optical measurements usually show very strong correlation to the water sample data. This approach was tested on Lake Balaton, Hungary in September 2008. Lake Balaton is characterized by its large area (597 km2), elongated shape and relatively shallow water depth (avg 3,2 m). The lake has a strong trophic gradient from the SW to the NE, the main tributary river carries large amounts of CDOM and suspended sediment concentrations can be very high because the lake is shallow and the sediment is fine grained. We measured in diverse weather conditions, and in an enclosed bay, a narrow strait and a large area of open water. 28 water samples were collected during the LIDAR measurement and the CDOM, chlorophyll and suspended sediment concentrations were measured in the laboratory using classic hydrological methods. These results were used to calibrate the LIDAR measurements with R2 values between 0,90 and 0,95. The relative values measured by the LIDAR were converted to absolute values using this regression, and the point-by-point results were interpolated into a raster with a cell size equal to the spatial resolution of

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

    PubMed

    Lysenko, Vladimir

    2012-05-01

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

  5. [Effects of NaCl stress on Hovenia dulcis and Gleditsia sinensis seedlings growth, chlorophyll fluorescence, and active oxygen metabolism].

    PubMed

    Feng, Lei; Bai, Zhi-ying; Lu, Bing-she; Cai, Sheng-wen; Feng, Li-na

    2008-11-01

    With potted Hovenia dulcis and Gleditsia sinensis seedlings as test materials, their plant growth, chlorophyll fluorescence characteristics, and active oxygen metabolism under stress of different concentration (0, 0.15%, 0.30%, 0.45%, and 0.60%) NaCl were studied. The results showed that with increasing concentration of NaCl, the plant growth, leaf chlorophyll content, photochemical efficiency of PS II (Fv/Fm), quantum yield of PS II (phi(PS II)), and photochemical quenching (q(P)) decreased gradually, while the non-photochemical quenching of fluorescence (q(N)) was in adverse. After 10 days of 0. 15% NaCl stress, the leaf chlorophyll content, Fv/Fm, phi(PS II), and q(P) of H. dulcis seedlings decreased by 19.77%, 2.94%, 29.03%, and 8.16%, respectively, with significant differences (P<0.05) to the control, while no significant differences were observed for G. sinensis seedlings. Compared with the control, the Fv/Fm and phi(PS II), of G. sinensis seedlings in treatment 0.30% NaCl decreased significantly by 1.91% and 14.66%, and the chlorophyll content and q(P) of the seedling in treatment 0.45% NaCl decreased significantly by 29.28% and 11.36%, respectively (P<0.05). With increasing concentration of NaCl, the SOD activity of G. sinensis seedlings showed a consistent increasing trend, and that of H. dulcis seedlings increased first and decreased then. The POD and CAT activities of G. sinensis and H. dulci seedlings tended to increase first and decrease then, with the increment being higher for G. sinensis than for H. dulci, while the MDA content of the seedlings had an increasing trend, with the increment being higher for H. dulcis than for G. sinensis, suggesting that the cell membrane lipid peroxidation of H. dulcis was more serious than that of G. sinensis. It was concluded that G. sinensis had greater salt tolerance than H. dulcis, which was related toits higher anti-oxidation enzyme activities.

  6. Photosynthetic acclimation to light in woody and herbaceous species: a comparison of leaf structure, pigment content and chlorophyll fluorescence characteristics measured in the field.

    PubMed

    Hallik, L; Niinemets, U; Kull, O

    2012-01-01

    Acclimation of foliage photosynthetic properties occurs with varying time kinetics, but structural, chemical and physiological factors controlling the kinetics of acclimation are poorly understood, especially in field environments. We measured chlorophyll fluorescence characteristics, leaf total carotenoid (Car), chlorophyll (Chl) and nitrogen (N) content and leaf dry mass per area (LMA) along vertical light gradients in natural canopies of the herb species, Inula salicina and Centaurea jacea, and tree species, Populus tremula and Tilia cordata, in the middle of the growing season. Presence of stress was assessed on the basis of night measurements of chlorophyll fluorescence. Our aim was to compare the light acclimation of leaf traits, which respond to light availability at long (LMA and N), medium (Chl a/b ratio, Car/Chl ratio) and short time scales (fluorescence characteristics). We found that light acclimation of nitrogen content per unit leaf area (N(area)), chlorophyll content per unit dry mass (Chl(mass)) and Chl/N ratio were related to modifications in LMA. The maximum PSII quantum yield (F(v) /F(m)) increased with increasing growth irradiance in I. salicina and P. tremula but decreased in T. cordata. Leaf growth irradiance, N content and plant species explained the majority of variability in chlorophyll fluorescence characteristics, up to 90% for steady-state fluorescence yield, while the contribution of leaf total carotenoid content was generally not significant. Chlorophyll fluorescence characteristics did not differ strongly between growth forms, but differed among species within a given growth form. These data highlight that foliage acclimation to light is driven by interactions between traits with varying time kinetics.

  7. Global spectral-kinetic analysis of room temperature chlorophyll a fluorescence from light-harvesting antenna mutants of barley.

    PubMed

    Gilmor, A M; Itoh, S; Govindjee

    2000-10-29

    This study presents a novel measurement, and simulation, of the time-resolved room temperature chlorophyll a fluorescence emission spectra from leaves of the barley wild-type and chlorophyll-b-deficient chlorina (clo) f2 and f104 mutants. The primary data were collected with a streak-camera-based picosecond-pulsed fluorometer that simultaneously records the spectral distribution and time dependence of the fluorescence decay. A new global spectral-kinetic analysis programme method, termed the double convolution integral (DCI) method, was developed to convolve the exciting laser pulse shape with a multimodal-distributed decay profile function that is again convolved with the spectral emission band amplitude functions. We report several key results obtained by the simultaneous spectral-kinetic acquisition and DCI methods. First, under conditions of dark-level fluorescence, when photosystem II (PS II) photochemistry is at a maximum at room temperature, both the clo f2 and clo f104 mutants exhibit very similar PS II spectral-decay contours as the wild-type (wt), with the main band centred around 685 nm. Second, dark-level fluorescence is strongly influenced beyond 700 nm by broad emission bands from PS I, and its associated antennae proteins, which exhibit much more rapid decay kinetics and strong integrated amplitudes. In particular a 705-720 nm band is present in all three samples, with a 710 nm band predominating in the clo f2 leaves. When the PS II photochemistry becomes inhibited, maximizing the fluorescence yield, both the clo f104 mutant and the wt exhibit lifetime increases for their major distribution modes from the minimal 205-500 ps range to the maximal 1500-2500 ps range for both the 685 nm and 740 nm bands. The clo f2 mutant, however, exhibits several unique spectral-kinetic properties, attributed to its unique PS I antennae and thylakoid structure, indicating changes in both PS II fluorescence reabsorption and PS II to PS I energy transfer pathways

  8. Chlorophyll fluorescence imaging as a tool to monitor the progress of a root pathogen in a perennial plant.

    PubMed

    Ivanov, Dimitre A; Bernards, Mark A

    2016-01-01

    The chlorophyll fluorescence parameter ΦNO is an excellent metric for the non-destructive monitoring of disease progression, measured over a broad range of light intensities. The suitability of the slow induction chlorophyll fluorescence parameters ΦPSII, ΦNPQ, and ΦNO to monitor in vivo disease progression in a host-root pathogen pathosystem was evaluated and compared to the established method of monitoring disease by measuring Fv/Fm. Using the infection of ginseng plants (Panax quinquefolius L.) with Pythium irregulare Buisman as a model, light response curves were used to establish the optimal irradiance for the resolution of differences between fluorescence parameters ΦPSII, ΦNPQ and ΦNO. As infection progressed only changes in ΦNO remained consistent with increased irradiance, and increased as infection progressed. Furthermore, ΦNO showed a high sensitivity for distinguishing increased disease load. In contrast, the magnitude in change of ΦPSII and ΦNPQ were sensitive to irradiance levels. The magnitude of increase in ΦNO per unit disease score was equivalent to the corresponding decline in Fv/Fm values. Thus ΦNO is as sensitive as Fv/Fm in monitoring biotic stress. The ability to measure ΦNO under a wide range of light intensities, including natural light, potentially without the need for dark adaptation, means that it can be used in the development of a general protocol for non-invasive, in vivo monitoring of plant health, from the laboratory to the field scale.

  9. Estimating chlorophyll concentrations in the optically complex waters of the North Aegean Sea from field and satellite ocean colour measurements

    NASA Astrophysics Data System (ADS)

    Drakopoulos, P. G.; Banks, A. C.; Kakagiannis, G.; Karageorgis, A. P.; Lagaria, A.; Papadopoulou, A.; Psarra, S.; Spyridakis, N.; Zervakis, V.

    2015-06-01

    In the Aegean Sea and Eastern Mediterranean there are large discrepancies between in situ and satellite ocean colour derived chlorophyll concentrations. The quantity that is monitored by ocean colour satellites and that can be used in the estimation of chlorophyll concentration is the remote sensing reflectance, defined as the ratio of the water leaving spectral radiance to the downwelling spectral irradiance. It can be determined in the field, with either above or in-water radiance and irradiance measurements. The complex optical properties of the North-East Aegean Sea, including radiance and irradiance, were studied during the AegeanMarTech project. Chlorophyll concentration estimates were derived from simultaneous above and in-water radiometric measurements. These were validated against chlorophyll concentration field data and compared against concurrent MODIS data from which chlorophyll was derived using two simple empirical algorithms. It was found that the MedOC3 algorithm outperforms the operational OC3M-547 algorithm and produces the least bias when compared against HPLC derived in situ chlorophyll. It is concluded that the greatest uncertainty in the inversion arises due to CDOM absorption below the 488 nm band. The reflectance ratios indicated that there is always an excess of yellow matter present in the study area and the water type could not be characterized optically as `'typical open ocean" Case 1.

  10. The application of unmanned aerial vehicle to precision agriculture: Chlorophyll, nitrogen, and evapotranspiration estimation

    NASA Astrophysics Data System (ADS)

    Elarab, Manal

    Precision agriculture (PA) is an integration of a set of technologies aiming to improve productivity and profitability while sustaining the quality of the surrounding environment. It is a process that vastly relies on high-resolution information to enable greater precision in the management of inputs to production. This dissertation explored the usage of multispectral high resolution aerial imagery acquired by an unmanned aerial systems (UAS) platform to serve precision agriculture application. The UAS acquired imagery in the visual, near infrared and thermal infrared spectra with a resolution of less than a meter (15--60 cm). This research focused on developing two models to estimate cm-scale chlorophyll content and leaf nitrogen. To achieve the estimations a well-established machine learning algorithm (relevance vector machine) was used. The two models were trained on a dataset of in situ collected leaf chlorophyll and leaf nitrogen measurements, and the machine learning algorithm intelligently selected the most appropriate bands and indices for building regressions with the highest prediction accuracy. In addition, this research explored the usage of the high resolution imagery to estimate crop evapotranspiration (ET) at 15 cm resolution. A comparison was also made between the high resolution ET and Landsat derived ET over two different crop cover (field crops and vineyards) to assess the advantages of UAS based high resolution ET. This research aimed to bridge the information embedded in the high resolution imagery with ground crop parameters to provide site specific information to assist farmers adopting precision agriculture. The framework of this dissertation consisted of three components that provide tools to support precision agriculture operational decisions. In general, the results for each of the methods developed were satisfactory, relevant, and encouraging.

  11. Light-induced changes in the fluorescence yield of chlorophyll a in vivo. II. Chlorella pyrenoidosa.

    PubMed

    Papageorgiou, G; Govindjee

    1968-11-01

    The long-term fluorescence induction in Chlorella pyrenoidosa consists of a fast rise of the fluorescence yield from the level S (of the first wave transient) to a maximum M, followed by slower decay to a terminal stationary level T. The maximum M is attained within 40 seconds from the onset of illumination while the decay to the terminal level T lasts for several minutes. The fluorescence rise (S --> M) coincides with an increase in the rate of oxygen evolution, which, however, remains constant during the fluorescence decay (M --> T). Poisons of photosynthesis 3, (3,4-dichlorophenyl)-1,1 dimethylurea (DCMU, o-phenathroline) inhibit the fluorescence induction, while uncouplers of photophosphorylation affect the fluorescence time course only when they function at an early stage of the coupling sequence e.g., carbonyl cyanide p-trifluoremethoxy phenylhydrazone, (FCCP, atabrin). Phosphorylation inhibitors affecting only the terminal esterification step (phlorizin) have little effect on the fluorescence kinetics. These results suggest that the fluorescence induction requires the operation of a phosphorylating electron transport and that it is possibly related to the light-induced structural changes which accompany photophosphorylation.

  12. Linking chlorophyll fluorescence, hyperspectral reflectance and plant physiological responses to detect stress using the photochemical reflectance index (PRI) (Invited)

    NASA Astrophysics Data System (ADS)

    Naumann, J. C.; Young, D.; Anderson, J.

    2009-12-01

    The concept of using vegetation as sentinels to indicate natural or anthropogenic stress is not new and could potentially provide an ideal mechanism for large-scale detection. Advances in fluorescence spectroscopy and reflectance-derived fluorescence have made possible earlier detection of stress in plants, especially before changes in chlorophyll content are visible. Our studies have been used to fuse leaf fluorescence and reflectance characteristics to remotely sense and rapidly detect vegetation stress and terrain characteristics. Laboratory studies have indicated that light-adapted fluorescence (ΔF/F‧m) measurements have been successful in all experiments at detecting stress from flooding, salinity, drought, herbicide and TNT contamination prior to visible signs of damage. ΔF/F‧m was related to plant physiological status in natural stress conditions, as seen in the relationships with stomatal conductance and photosynthesis The photochemical reflectance index (PRI) and other reflectance ratios were effective at tracking changes in ΔF/F‧m at the leaf and canopy-level scales. At the landscape-level, chlorophyll fluorescence and airborne reflectance imagery were used to evaluate spatial variations in stress in the dominant shrub on a barrier island, Myrica cerifera, during a severe drought and compared to an extremely wet year. Measurements of relative water content and the water band index (WBI970) indicated that water stress did not vary across the island. In contrast, there were significant differences in tissue chlorides across sites. Using PRI we were able to detect salinity stress across the landscape. PRI did not differ between wet and dry years. There was a positive relationship between PRI and ΔF/F‧m for M. cerifera (r2 = 0.79). The normalized difference vegetation index (NDVI), the chlorophyll index (CI) and WBI970 were higher during the wet summer but varied little across the island. PRI was not significantly related to NDVI, suggesting that

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

    PubMed

    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.

  14. [Effects of foliar spraying methyl jasmonate on leaf chlorophyll fluorescence characteristics of flue-cured tobacco seedlings under drought and re-watering].

    PubMed

    Jin, Wei-Wei; Wang, Yan; Zhang, Hui-Hui; Jiao, Zhi-Li; Wang, Peng; Li, Xin; Yue, Bing-Bing; Sun, Guang-Yu

    2011-12-01

    Taking the flue-cured tobacco variety of "Longjiang 911" from Heilongjiang Province of Northeast China as test material, a pot experiment was conducted to study the effects of foliar spraying different concentration methyl jasmonate (MeJA) on the seedlings leaf chlorophyll content and chlorophyll fluorescence characteristics during the transplantation stage under drought and re-watering. Under drought condition, the leaf chlorophyll content, maximum fluorescence (F(m)), potential activities of PSII (F(v)/F(o)), maximum photochemical efficiency (F(v)/F(m)), actual photochemical efficiency (psi(PSII)), apparent electron transport rate (ETR), and photochemical quenching (q(P)) decreased, but the minimal fluorescence (F(o)) and non-photochemical quenching (q(N)) increased. Foliar spraying 0.2 and 0.5 mmol x L(-1) of MeJA had obvious positive effects in mitigating the decrease of F(v)/F(m), F(v)/F(o), phi(PSII), ETR, and q(P) and the increase of q(N) under drought stress, while spraying 1.0 mmol x L(-1) of MeJA had lesser effects. After re-watering, all the leaf chlorophyll fluorescence indices had obvious recovery, and spraying MeJA made the indices more close to the original levels before drought. It was suggested that foliar spraying MeJA could alleviate the degradation of chlorophyll and play definite role in protecting the PSII under drought stress, decrease the damage of drought stress on the seedlings, promote the rapid MeJA recovery of chlorophyll fluorescence parameters after re-watering, and thus, ensure the regrowth of flue-cured tobacco seedlings.

  15. Chlorophyll fluorescence quenching during ozone exposure of leaves of Phaseolus vulgaris (pinto)

    SciTech Connect

    Guralnick, L.J. ); Miller, R.; Heath, R.L. )

    1990-05-01

    During ozone exposure, observations have noted an initial decrease in CO{sub 2} uptake followed by a decrease in stomatal conductance. We examined this response utilizing the technique of fluorescence quenching. Fourteen day old plants were exposed to 0.3 ul/l ozone for 1 hour. Fluorescence quenching was monitored using the Hanstech modulated fluorescence system. This enabled us to measure changes in photochemical quenching (qQ) and non-photochemical quenching (qE) in control and ozone treated plants. Results have indicated no differences in qQ and qE between ozone treated and control plants. We are initiating further studies utilizing different ozone levels.

  16. On the relationship between the non-photochemical quenching of the chlorophyll fluorescence and the Photosystem II light harvesting efficiency. A repetitive flash fluorescence induction study.

    PubMed

    Koblízek, M; Kaftan, D; Nedbal, L

    2001-01-01

    Plants respond to excess light by a photoprotective reduction of the light harvesting efficiency. The notion that the non-photochemical quenching of chlorophyll fluorescence can be reliably used as an indicator of the photoprotection is put to a test here. The technique of the repetitive flash fluorescence induction is employed to measure in parallel the non-photochemical quenching of the maximum fluorescence and the functional cross-section (sigma(PS II)) which is a product of the photosystem II optical cross-section a(PS II) and of its photochemical yield Phi(PS II) (sigma (PS II) = a(PS II) Phi(PS II)). The quenching is measured for both, the maximum fluorescence found in a single-turnover flash (F(M) (ST)) and in a multiple turnover light pulse (F(M) (MT)). The experiment with the diatom Phaeodactylum tricornutum confirmed that, in line with the prevalent model, the PS II functional cross-section sigma (PS II) is reduced in high light and restored in the dark with kinetics and amplitude that are closely matching the changes of the F(M) (ST) and F(M) (MT) quenching. In contrast, a poor correlation between the light-induced changes in the PS II functional cross-section sigma (PS II) and the quenching of the multiple-turnover F(M) (MT) fluorescence was found in the green alga Scenedesmus quadricauda. The non-photochemical quenching in Scenedesmus quadricauda was further investigated using series of single-turnover flashes given with different frequencies. Several mechanisms that modulate the fluorescence emission in parallel to the Q(A) redox state and to the membrane energization were resolved and classified in relation to the light harvesting capacity of Photosystem II.

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

    PubMed

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

    2014-01-15

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

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

    PubMed

    Wang, WeiBo; Yang, CuiYun; Tang, DongShan; Li, DunHai; Liu, YongDing; Hu, ChunXiang

    2007-08-01

    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 2 cm). 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 different 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 polysaccharides 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 photosystem II (PS II) after rehydration.

  19. Mapping grape berry photosynthesis by chlorophyll fluorescence imaging: the effect of saturating pulse intensity in different tissues.

    PubMed

    Breia, Richard; Vieira, Sónia; da Silva, Jorge Marques; Gerós, Hernâni; Cunha, Ana

    2013-01-01

    Grape berry development and ripening depends mainly on imported photosynthates from leaves, however, fruit photosynthesis may also contribute to the carbon economy of the fruit. In this study pulse amplitude modulated chlorophyll fluorescence imaging (imaging-PAM) was used to assess photosynthetic properties of tissues of green grape berries. In particular, the effect of the saturation pulse (SP) intensity was investigated. A clear tissue-specific distribution pattern of photosynthetic competence was observed. The exocarp revealed the highest photosynthetic capacity and the lowest susceptibility to photoinhibition, and the mesocarp exhibited very low fluorescence signals and photochemical competence. Remarkably, the seed outer integument revealed a photosynthetic ability similar to that of the exocarp. At a SP intensity of 5000 μmol m(-2) s(-1) several photochemical parameters were decreased, including maximum fluorescence in dark-adapted (F(m)) and light-adapted (F'(m)) samples and effective quantum yield of PSII (Φ(II)), but the inner tissues were susceptible to a SP intensity as low as 3200 μmol m(-2) s(-1) under light-adapted conditions, indicating a photoinhibitory interaction between SP and actinic light intensities and repetitive exposure to SP. These results open the way to further studies concerning the involvement of tissue-specific photosynthesis in the highly compartmentalized production and accumulation of organic compounds during grape berry development. © 2013 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2013 The American Society of Photobiology.

  20. Chlorophyll a and NADPH fluorescence lifetimes in the microalgae Haematococcus pluvialis (Chlorophyceae) under normal and astaxanthin-accumulating conditions.

    PubMed

    Kristoffersen, Arne S; Svensen, Øyvind; Ssebiyonga, Nicolausi; Erga, Svein R; Stamnes, Jakob J; Frette, Øyvind

    2012-10-01

    In vivo fluorescence lifetimes of chlorophyll-a (chl-a) and nicotinamide adenine dinucleotide phosphate (NADPH) were obtained from the green microalgae Haematococcus pluvialis under normal and nutrient-stressed conditions (green stage and red stage, respectively), using two-photon excitation provided by a laser generating pulses in the femtosecond range, and a Leica microscope setup. Analysis of the fluorescence lifetime decay curve revealed two separate lifetime components in all our measurements. A short-lifetime component for chl-a of ~250 ps was completely dominant, contributing more than 90% of overall intensity in both green-stage and red-stage cells. Green-stage cells inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethyl-urea (DCMU) displayed a significant chl-a lifetime increase for the short component. However, this was not the case for red-stage cells, in which DCMU inhibition did not significantly affect the lifetime. For green-stage cells, we found a short NADPH (free) lifetime component at ~150 ps to be completely dominating, but for red-stage cells, a longer component (protein bound) at ~3 ns contributed as much as 35% of the total intensity. We hypothesize that the long lifetime component of NADPH is connected to photoprotection in the cells and coupled to production of astaxanthin. DCMU does not seem to affect the fluorescence lifetimes of NADPH.

  1. Effects of UVB radiation on Photosynthesis Activity of Wolffia arrhiza as Probed by Chlorophyll Fluorescence Transient

    NASA Astrophysics Data System (ADS)

    Wang, Gaohong; Hao, Zongjie; Chen, Kun; Liu, Yongding

    UV radiation is one major environmental stress for growth of Wolffia arrhiza which is regarded as a good candidate producer for establishing CELSS during extraterrestrial colonization and spaceflight. In this study, we found that UVB radiation inhibited photosynthetic CO2 assimilation activity significantly, and the content of chlorophyll a, chlorophyll b and carotenoids decreased obviously when plants were exposed to UVB radiation for 6 h. High UVB radiation also declined the quantum yield of primary photochemistry (φPo), the quantum yield for electron transport (φEo) and the efficiency per trapped excitation (ψo) in the cells of Wolffia arrhiza simultaneously, while the amount of active PSII reaction centers per excited cross section (RC/CS) and the total number of active reaction center per absorption (RC/ABS) had the same changes under UV-B radiation stress. These results indicated that the effects of UV- B radiation on photosynthesis of Wolffia arrhiza maybe functioned by inhibition the electron transport and inactivation of reaction centers, but the inhibition maybe happen in more than one site in photosynthetic apparatus which is different to that in salt adaptation.

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

    PubMed

    Wittmann, Christiane; Matyssek, Rainer; Pfanz, Hardy; Humar, Maja

    2007-11-01

    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.

  3. LETTERS TO THE EDITOR: Emission of fluorescence from chlorophyll a in vivo due to nanosecond pulsed laser excitation

    NASA Astrophysics Data System (ADS)

    Bunin, D. K.; Gorbunov, M. Yu; Fadeev, V. V.; Chekalyuk, A. M.

    1992-05-01

    A model was proposed and tested experimentally to describe the emission of fluorescence by chlorophyll a in vivo as a result of pulsed laser excitation. This model takes into account the migration of excitons between various photosynthetic units, singlet-singlet annihilation of excitons, pigment bleaching, and also the influence of various states of the photosystem II reaction centers. A method was developed to measure the average number of excitons reaching a photosystem II reaction center during a pulse. This involved two-pulse laser excitation. It was found that the rates of exciton capture by the reaction centers were the same for the PIQ and P +IQ - states of the photosystem II reaction centers, whereas the rate of exciton capture in the P +I -Q - state was half that for the PIQ - state.

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

    PubMed

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

    2015-10-01

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

  5. Effects of Cadmium Stress on Leaf Chlorophyll Fluorescence and Photosynthesis of Elsholtzia argyi--A Cadmium Accumulating Plant.

    PubMed

    Li, Siliang; Yang, Wenhao; Yang, Tingting; Chen, Yan; Ni, Wuzhong

    2015-01-01

    A hydroponic experiment was conducted to investigate the effects of cadmium (Cd) on chlorophyll fluorescence and photosynthetic parameters on a Cd accumulating plant of Elsholtzia argyi. Four weeks-seedlings of E. argyi were treated with 0 (CK) 5, 10, 15, 20, 25, 30, 40, 50 and 100 μmol L(-1) Cd for 21 days. Fv/Fo, Fv/Fm, qP, ΦPSП, ETR and Fv'/Fm' were significantly increased under low Cd (5-15 μmol L(-1) for Fv/Fo, Fv/Fm and qP, 5-10 μmol L(-1) for ΦPSП, ETR and Fv'/Fm') stress, and these parameters were similar to control under Cd≤50 μmol L(-1). All above parameters were significantly decreased at 100 μmol L(-1) Cd. Compared with control, Pn was significantly (P<0.05) increased under 5-30 μmol L(-1) Cd. However, 50 and 100 μmol L(-1) Cd significantly (P < 0.05) reduced it. Gs and Tr were substantially decreased at 50-100 and 40-100 μmol L(-1) Cd, respectively. Ci was significantly increased at 50 and 100 μmol L(-1) Cd. High Cd-induced decrease of Pn is not only connected to stomatal limitation but also to the inhibition of Fv/Fo, Fv/Fm, ΦPSП, qP, ETR and increase of NPQ. Maintain chlorophyll fluorescence and photosynthesis parameters under its Cd tolerance threshold were one of tolerance mechanisms in E. argyi.

  6. Hyperspectral and Chlorophyll Fluorescence Imaging to Analyse the Impact of Fusarium culmorum on the Photosynthetic Integrity of Infected Wheat Ears

    PubMed Central

    Bauriegel, Elke; Giebel, Antje; Herppich, Werner B.

    2011-01-01

    Head blight on wheat, caused by Fusarium spp., is a serious problem for both farmers and food production due to the concomitant production of highly toxic mycotoxins in infected cereals. For selective mycotoxin analyses, information about the on-field status of infestation would be helpful. Early symptom detection directly on ears, together with the corresponding geographic position, would be important for selective harvesting. Hence, the capabilities of various digital imaging methods to detect head blight disease on winter wheat were tested. Time series of images of healthy and artificially Fusarium-infected ears were recorded with a laboratory hyperspectral imaging system (wavelength range: 400 nm to 1,000 nm). Disease-specific spectral signatures were evaluated with an imaging software. Applying the ‘Spectral Angle Mapper’ method, healthy and infected ear tissue could be clearly classified. Simultaneously, chlorophyll fluorescence imaging of healthy and infected ears, and visual rating of the severity of disease was performed. Between six and eleven days after artificial inoculation, photosynthetic efficiency of infected compared to healthy ears decreased. The severity of disease highly correlated with photosynthetic efficiency. Above an infection limit of 5% severity of disease, chlorophyll fluorescence imaging reliably recognised infected ears. With this technique, differentiation of the severity of disease was successful in steps of 10%. Depending on the quality of chosen regions of interests, hyperspectral imaging readily detects head blight 7 d after inoculation up to a severity of disease of 50%. After beginning of ripening, healthy and diseased ears were hardly distinguishable with the evaluated methods. PMID:22163820

  7. Non-destructive estimation of foliar chlorophyll and carotenoid contents: Focus on informative spectral bands

    NASA Astrophysics Data System (ADS)

    Kira, Oz; Linker, Raphael; Gitelson, Anatoly

    2015-06-01

    Leaf pigment content provides valuable insight into the productivity, physiological and phenological status of vegetation. Measurement of spectral reflectance offers a fast, nondestructive method for pigment estimation. A number of methods were used previously for estimation of leaf pigment content, however, spectral bands employed varied widely among the models and data used. Our objective was to find informative spectral bands in three types of models, vegetation indices (VI), neural network (NN) and partial least squares (PLS) regression, for estimating leaf chlorophyll (Chl) and carotenoids (Car) contents of three unrelated tree species and to assess the accuracy of the models using a minimal number of bands. The bands selected by PLS, NN and VIs were in close agreement and did not depend on the data used. The results of the uninformative variable elimination PLS approach, where the reliability parameter was used as an indicator of the information contained in the spectral bands, confirmed the bands selected by the VIs, NN, and PLS models. All three types of models were able to accurately estimate Chl content with coefficient of variation below 12% for all three species with VI showing the best performance. NN and PLS using reflectance in four spectral bands were able to estimate accurately Car content with coefficient of variation below 14%. The quantitative framework presented here offers a new way of estimating foliar pigment content not requiring model re-parameterization for different species. The approach was tested using the spectral bands of the future Sentinel-2 satellite and the results of these simulations showed that accurate pigment estimation from satellite would be possible.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    As well as a proxy of ecosystem level photosynthesis, sun-induced fluorescence (SIF) is expected to be an indicator of plant physiological information in photosynthesis (Frankenberg et al., 2011). Zhang et al. (2014) especially suggested that the SIF can be used to estimate the capacity of RuBP carboxylation, Vcmax, at the ecosystem scale by the simple inversion approach with the combination of both observation and modeling. However, the seasonal pattern of the relationships between SIF and such gas exchange physiological parameters has not been confirmed by the direct field observation, yet. Here, we present the field ob