WorldWideScience

Sample records for coral chlorophyll contents

  1. Evaluation of Chlorophyll Content and Chlorophyll Fluorescence Parameters and Relationships between Chlorophyll a, b and Chlorophyll Content Index under Water Stress in Olea europaea cv. Dezful

    OpenAIRE

    E. Khaleghi; K. Arzani; N. Moallemi; M. Barzegar

    2012-01-01

    This study was conducted to determine effect of water stress on chlorophyll content and chlorophyll fluorescence parameter in young `Dezful- olive trees. Three irrigation regimes (40% ETcrop, 65% ETcrop and 100% ETcrop) were used. After irrigation treatments were applied, some of biochemical parameters including chlorophyll a, b, total chlorophyll, chlorophyll fluorescence and also chlorophyll content index (C.C.I) were measured. Results of Analysis of variance showed that irrigation treatmen...

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

    NARCIS (Netherlands)

    Girma, A.; Skidmore, A.K.; Bie, de C.A.J.M.; Bongers, F.; Schlerf, M.

    2013-01-01

    Quantification of chlorophyll content provides useful insight into the physiological performance of plants. Several leaf chlorophyll estimation techniques, using hyperspectral instruments, are available. However, to our knowledge, a non-destructive bark chlorophyll estimation technique is not

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

    NARCIS (Netherlands)

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

    2013-01-01

    Quantification of chlorophyll content provides useful insight into the physiological performance of plants. Several leaf chlorophyll estimation techniques, using hyperspectral instruments, are available. However, to our knowledge, a non-destructive bark chlorophyll estimation technique is not

  4. Chlorophyll meter reading and total nitrogen content applied as ...

    African Journals Online (AJOL)

    Ana Mascarello

    The present study was aimed to assess the relationship between the reading of the chlorophyll meter and the total nitrogen (N) content ... devices to measure chlorophyll index (SPAD) and N content in the leaf. The nitrogen levels were found ... absorption of other nutrients and the production of carbohydrates. The methods ...

  5. Optical Method for Estimating the Chlorophyll Contents in Plant Leaves.

    Science.gov (United States)

    Pérez-Patricio, Madaín; Camas-Anzueto, Jorge Luis; Sanchez-Alegría, Avisaí; Aguilar-González, Abiel; Gutiérrez-Miceli, Federico; Escobar-Gómez, Elías; Voisin, Yvon; Rios-Rojas, Carlos; Grajales-Coutiño, Ruben

    2018-02-22

    This work introduces a new vision-based approach for estimating chlorophyll contents in a plant leaf using reflectance and transmittance as base parameters. Images of the top and underside of the leaf are captured. To estimate the base parameters (reflectance/transmittance), a novel optical arrangement is proposed. The chlorophyll content is then estimated by using linear regression where the inputs are the reflectance and transmittance of the leaf. Performance of the proposed method for chlorophyll content estimation was compared with a spectrophotometer and a Soil Plant Analysis Development (SPAD) meter. Chlorophyll content estimation was realized for Lactuca sativa L., Azadirachta indica , Canavalia ensiforme , and Lycopersicon esculentum . Experimental results showed that-in terms of accuracy and processing speed-the proposed algorithm outperformed many of the previous vision-based approach methods that have used SPAD as a reference device. On the other hand, the accuracy reached is 91% for crops such as Azadirachta indica , where the chlorophyll value was obtained using the spectrophotometer. Additionally, it was possible to achieve an estimation of the chlorophyll content in the leaf every 200 ms with a low-cost camera and a simple optical arrangement. This non-destructive method increased accuracy in the chlorophyll content estimation by using an optical arrangement that yielded both the reflectance and transmittance information, while the required hardware is cheap.

  6. Optical Method for Estimating the Chlorophyll Contents in Plant Leaves

    Directory of Open Access Journals (Sweden)

    Madaín Pérez-Patricio

    2018-02-01

    Full Text Available This work introduces a new vision-based approach for estimating chlorophyll contents in a plant leaf using reflectance and transmittance as base parameters. Images of the top and underside of the leaf are captured. To estimate the base parameters (reflectance/transmittance, a novel optical arrangement is proposed. The chlorophyll content is then estimated by using linear regression where the inputs are the reflectance and transmittance of the leaf. Performance of the proposed method for chlorophyll content estimation was compared with a spectrophotometer and a Soil Plant Analysis Development (SPAD meter. Chlorophyll content estimation was realized for Lactuca sativa L., Azadirachta indica, Canavalia ensiforme, and Lycopersicon esculentum. Experimental results showed that—in terms of accuracy and processing speed—the proposed algorithm outperformed many of the previous vision-based approach methods that have used SPAD as a reference device. On the other hand, the accuracy reached is 91% for crops such as Azadirachta indica, where the chlorophyll value was obtained using the spectrophotometer. Additionally, it was possible to achieve an estimation of the chlorophyll content in the leaf every 200 ms with a low-cost camera and a simple optical arrangement. This non-destructive method increased accuracy in the chlorophyll content estimation by using an optical arrangement that yielded both the reflectance and transmittance information, while the required hardware is cheap.

  7. Effects of biocides on chlorophyll contents of detached basil leaves

    Directory of Open Access Journals (Sweden)

    Titima Arunrangsi

    2013-06-01

    Full Text Available Herbicides and insecticides have been widely and intensively used in agricultural areas worldwide to enhance crop yield. However, many biocides cause serious environmental problems. In addition, the biocides may also have some effects on the treated agricultural crops. To study effects of biocides on chlorophyll content in detached basil leaves, 2,4-D dimethylamine salt (2,4 D-Amine, paraquat, carbosulfan, and azadirachtin, were chosen as representatives of biocide. After applying the chemicals to detached basil leaves overnight in darkness, chlorophyll contents were determined. Only treatment with 2,4 D-Amine resulted in reduction of chlorophyll contents significantly compared to treatment with deionized (DI water. In the case of paraquat and carbosulfan, chlorophyll contents were not significantly changed, while slightly higher chlorophyll contents, compared to DI water, after the treatment with azadirachtin, were observed. The results indicated that 2,4 D-Amine shows an ability to accelerate chlorophyll degradation, but azadirachtin helps to retard chlorophyll degradation, when each biocide is used at the concentration recommended by the manufacturer.

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    Chlorophyll-a fluorescence was measured in six species of coral, using pulse-amplitude-modulated fluorometers employing fibre-optic probes with diameters of 8 mm, 1 mm and 140 µm. The 8-mm probe integrated responses over a large area, giving more weight to coenosarc than polyp tissue for Acropora...

  9. Estimating chlorophyll content from Eucalyptus dunnii leaves by reflectance values

    Directory of Open Access Journals (Sweden)

    João Alexandre Lopes Dranski

    2016-06-01

    Full Text Available This study aimed to estimate photosynthetic pigments contents from leaves of Eucalyptus dunni Maiden based on values of reflectance spectra of red, green and blue colors obtained with a digital color analyzer. We collected fifty leaves from the lower third of the crown of twenty trees including young as well as mature leaves. From each leaf an area of 14 cm2 of the leaf blade was cut in which we measured reflectance values on the red, green and blue spectra with a portable digital colorimeter, obtained relative index of chlorophyll with a SPAD – 502 and determined the content of the chlorophyll a, b, and a + b by classic method of solvent extraction. We submitted the data to multiple linear regression and nonlinear analysis at 5% of error probability. It was evaluated the occurrence of multicollinearity. The negative exponential model resulted in good fit when data from red spectrum was used for chlorophyll a, green spectrum for chlorophyll b and a + b, making possible correlation coefficients between the estimated values and the extracted above 0.85. Except for the chlorophyll a content, the accuracy in estimates of photosynthetic pigments were higher than estimated by the chlorophyll meter, even with linearity between methods. Therefore, it is possible to estimate photosynthetic pigments on E. dunni leaves through values of red and green wavelengths from a digital color analyser.

  10. Influence of vermicompost humic acid on chlorophyll content and ...

    African Journals Online (AJOL)

    Influence of vermicompost humic acid on chlorophyll content and acclimatization in banana clone, Enano Guantanamero. Marcia Beatriz Moya Fernández, Esteban Sánchez Chávez, Daniel Cabezas Montero, Andrés Calderín García, Dany Marrero López, Eduardo F. Héctor Ardisana, Sandra Pérez Álvarez ...

  11. Chlorophyll meter reading and total nitrogen content applied as ...

    African Journals Online (AJOL)

    The present study was aimed to assess the relationship between the reading of the chlorophyll meter and the total nitrogen (N) content in the leaf in different parts of the crambe plant, depending on the doses of nitrogen applied to the canopy. Randomized block design in a split plot experimental design was used. The plots ...

  12. Calibrations between chlorophyll meter values and chlorophyll contents vary as the result of differences in leaf structure

    Science.gov (United States)

    In order to relate leaf chlorophyll meter values with total leaf chlorophyll contents (µg cm-2), calibration equations are established with measured data on leaves. Many studies have documented differences in calibration equations using different species and using different growing conditions for th...

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

    Science.gov (United States)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    Science.gov (United States)

    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%.

  16. Estimate of Leaf Chlorophyll and Nitrogen Content in Asian Pear (Pyrus serotina Rehd. by CCM-200

    Directory of Open Access Journals (Sweden)

    Mostafa GHASEMI

    2011-03-01

    Full Text Available In many cases evaluation of chlorophyll and nitrogen content in plants need to destructive methods, more time and organic solvents. Application of chlorophyll meters save time and resources. The aim of this study was estimating of chlorophyll and nitrogen content in Asian pear leaves using non-destructive method and rapid quantification of chlorophyll by chlorophyll content meter (CCM-200. This study was conducted on 8 years old Asian pear trees during June 2008 in Tehran, Iran. To develop our regression model, the chlorophyll meter data were correlated with extracted chlorophyll and nitrogen content data obtained from DMSO and Kejeldal methods, respectively. The results showed that, there was positive and linear correlation between CCM-200 data and chlorophyll a (R�=0.7183, chlorophyll b (R�=0.8523, total chlorophyll (R�=0.90, and total nitrogen content (R�=0.76 in Asian pear leaves. Thus, it can be concluded that, CCM-200 can be used in order to predict both chlorophyll and nitrogen content in Asian pear leaves.

  17. The effects of heavy metal ions on the chlorophyll content and cell membrane permeability of charophytes

    International Nuclear Information System (INIS)

    Fu Hualong; Chen Hao; Dong Bin; Qing Renwei

    2001-01-01

    The authors studied the effects of several heavy metal ions in different concentrations (Cd 2+ , Hg 2+ , Pb 2+ , Cr 6+ ) on the chlorophyll content and cell membrane permeability of Chara vulgaris L. It was discovered that the effects of heavy metal ions on the chlorophyll content and cell membrane permeability of Chara vulgaris L. changed with their different concentration. The trend was that the chlorophyll content and cell membrane permeability were decreased with the increase of the heavy metal ions. The degree of chlorophyll content affected was Cr 6+ , Cd 2+ , Hg 2+ , Pb 2+ , and that of cell membrane permeability affected was Cd 2+ , Cr 6+ , Hg 2+ , Pb 2+

  18. Effect of automobile pollution on chlorophyll content of roadside urban trees

    Directory of Open Access Journals (Sweden)

    M. Iqbal

    2015-09-01

    Full Text Available The effect of automobile pollution was determined on chlorophyll content of four different tree species viz. Azadirachta indica L., Conocarpus erectus L., Guiacum officinale L.and Eucalyptus sp. growing along the roads of the city.  Significant changes in the level of chlorophyll “a”, chlorophyll “b” and total chlorophyll “a+b” were found in the leaves of four tree species (A. indica, C. erectus, G.officinale and Eucalyptus sp. collected from polluted sites (Airport, Malir Halt, Quaidabad as compared to control site (Karachi University Campus. Lowest concentration of chlorophyll “a”, chlorophyll “b” and chlorophyll “a+b” was recorded in the leaf samples of all tree species collected from Quaidabad site when compared with the leaf samples collected from control site. The highest levels of chlorophyll pigment were recorded in all tree species leave samples collected from Karachi University Campus.  Similarly, better levels of chlorophyll “a”, chlorophyll “b” and total chlorophyll “a+b” was observed in all tree species growing at Airport site as compared to plants growing at Malir Halt and Quaidabad sites.  This study clearly indicated that the vehicular activities induced air pollution problem and affected on the level of chlorophyll pigments in trees which were exposed to road side pollution.

  19. Influence of sulphur dioxide on chlorophyll content and catalase activity in some chosen lichen species

    Energy Technology Data Exchange (ETDEWEB)

    Kuziel, S

    1974-01-01

    The influence of SO/sub 2/ on changes in catalase activity and in chlorophyll content were investigated under laboratory conditions in several lichen species and in maize. In all the plants examined the chlorophyll content and catalase activity decreased after treatment with SO/sub 2/ as compared with that in the control plants.

  20. Using hyperspectral remote sensing data for retrieving canopy chlorophyll and nitrogen content

    NARCIS (Netherlands)

    Clevers, J.G.P.W.; Kooistra, L.

    2012-01-01

    Plant stress is often expressed as a reduction in amount of biomass or leaf area index (LAI). In addition, stress may affect the plant pigment system, influencing the photosynthetic capacity of plants. Chlorophyll content is the main driver for this primary production. The chlorophyll content is

  1. TOXICITY OF INDUSTRIAL EFFLUENT ON TOTAL CHLOROPHYLL CONTENT OF CERTAIN AQUATIC MACROPHYTES

    OpenAIRE

    Singh Priti; Vishen Ashish; Wadhwani R; Pandey Y.N

    2012-01-01

    To assess the toxicity of industrial effluents on certain macrophytes, the total chlorophyll content of free floating, submerged and emergent macrophytes were estimated in concentrations of industrial effluents at varying exposure duration. The result revealed reduction in total chlorophyll content of exposed macrophytes at higher concentrations of industrial effluents on prolonged duration.

  2. Influence of frequent magnetic field on chlorophyll content in leaves of sugar beet plants

    International Nuclear Information System (INIS)

    Rochalska, M.

    2005-01-01

    Chlorophyll content in plant leaves is correlated with the yield and nitrogen content in plants. Non-destructive investigations of chlorophyll content in leaves of 3 varieties of sugar beet grown from seeds revealed that a low frequent magnetic field, acting independently or in combination with other methods of seed improvement, increased chlorophyll content in leaves of the investigated plants. The treatment with the magnetic field increased nitrogen content in the examined plants. The effect was not connected with environmental conditions during vegetation seasons. (author)

  3. Rapid assessment of water pollution by airborne measurement of chlorophyll content.

    Science.gov (United States)

    Arvesen, J. C.; Weaver, E. C.; Millard, J. P.

    1971-01-01

    Present techniques of airborne chlorophyll measurement are discussed as an approach to water pollution assessment. The differential radiometer, the chlorophyll correlation radiometer, and an infrared radiometer for water temperature measurements are described as the key components of the equipment. Also covered are flight missions carried out to evaluate the capability of the chlorophyll correlation radiometer in measuring the chlorophyll content in water bodies with widely different levels of nutrients, such as fresh-water lakes of high and low eutrophic levels, marine waters of high and low productivity, and an estuary with a high sediment content. The feasibility and usefulness of these techniques are indicated.

  4. Hyperspectral imaging detection of decayed honey peaches based on their chlorophyll content.

    Science.gov (United States)

    Sun, Ye; Wang, Yihang; Xiao, Hui; Gu, Xinzhe; Pan, Leiqing; Tu, Kang

    2017-11-15

    Honey peach is a very common but highly perishable market fruit. When pathogens infect fruit, chlorophyll as one of the important components related to fruit quality, decreased significantly. Here, the feasibility of hyperspectral imaging to determine the chlorophyll content thus distinguishing diseased peaches was investigated. Three optimal wavelengths (617nm, 675nm, and 818nm) were selected according to chlorophyll content via successive projections algorithm. Partial least square regression models were established to determine chlorophyll content. Three band ratios were obtained using these optimal wavelengths, which improved spatial details, but also integrates the information of chemical composition from spectral characteristics. The band ratio values were suitable to classify the diseased peaches with 98.75% accuracy and clearly show the spatial distribution of diseased parts. This study provides a new perspective for the selection of optimal wavelengths of hyperspectral imaging via chlorophyll content, thus enabling the detection of fungal diseases in peaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Low light intensity and nitrogen starvation modulate the chlorophyll content of Scenedesmus dimorphus.

    Science.gov (United States)

    Ferreira, V S; Pinto, R F; Sant'Anna, C

    2016-03-01

    Chlorophyll is a photosynthetic pigment found in plants and algal organisms and is a bioproduct with human health benefits and a great potential for use in the food industry. The chlorophyll content in microalgae strains varies in response to environmental factors. In this work, we assessed the effect of nitrogen depletion and low light intensity on the chlorophyll content of the Scenedesmus dimorphus microalga. The growth of S. dimorphus under low light intensity led to a reduction in cell growth and volume as well as increased cellular chlorophyll content. Nitrogen starvation led to a reduction in cell growth and the chlorophyll content, changes in the yield and productivity of chlorophylls a and b. Transmission electron microscopy was used to investigate the ultrastructural changes in the S. dimorphus exposed to nitrogen and light deficiency. In contrast to nitrogen depletion, low light availability was an effective mean for increasing the total chlorophyll content of green microalga S. dimorphus. The findings acquired in this work are of great biotechnological importance to extend knowledge of choosing the right culture condition to stimulate the effectiveness of microalgae strains for chlorophyll production purposes. © 2015 The Society for Applied Microbiology.

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

    International Nuclear Information System (INIS)

    Ilyas, M.; Ilyas, N.; Arshad, M.; Kazi, A.G.

    2014-01-01

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

  7. Researches Regarding the Influence of Cold Storage on the Chlorophyll Content in Lettuce

    Directory of Open Access Journals (Sweden)

    Iuliana Cretescu

    2014-05-01

    Full Text Available The aim of the present investigations was to determine the effect of the cold storage period on the content of chlorophylls in the leaves of lettuce and arugula (rucola. The research material consisted in two types of lettuce (Lactuca sativa L. var. capitata; Lactuca sativa L. var. crispa and arugula (Eruca sativa purchased from supermarkets in Timisoara. The quantitative determination of chlorophyll pigments in leaves (SPAD was made by chlorophyll meter (SPAD 502 Konica-Minolta. During the few days cold storage at a temperature of 4ºC, the content of chlorophyll in the leaf significantly decreased, compared with that in the control group. After 3 days of cold storage arugula and lettuce (Lactuca sativa var. capitata values of chlorophyll content differ statistically very significantly (p<0.001 from the values found in the control group which for lettuce (Lactuca sativa L. var. crispa differs statistically significant (p < 0.05.

  8. Effect of gamma radiation on chlorophylls contents, net photosynthesis and respiration of chlorella pyrenoidosa

    International Nuclear Information System (INIS)

    Fernandez Gonzalez, J.; Martin Moreno, C.

    1983-01-01

    The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of chlorella pyrenoidosa has been studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and 5000 Gy, being, at first 'b' chlorophyll affected to a greater extent than 'a' chlorophyll. Net photosynthesis and respiration decline throughout the time of the observations after irradiation, this depressing effect being much more remarkable for the first one. Net photosynthesis inhibition levels of about 30% have got only five hours post irradiation at a dose of 5000 Gy. (author)

  9. The effect of shade on chlorophyll and anthocyanin content of upland red rice

    Science.gov (United States)

    Muhidin; Syam'un, E.; Kaimuddin; Musa, Y.; Sadimantara, G. R.; Usman; Leomo, S.; Rakian, T. C.

    2018-02-01

    Upland red rice (Oryza sativa) is a staple food and contains anthocyanin, which can act as antioxidants, plays an important role both for the plant itself and for human health. Levels of antioxidants in rice can be affected by the availability of light. The results showed that the difference of shade, cultivar, and interaction both significantly affect the content of chlorophyll a, chlorophyll b and total chlorophyll. The results also showed that shade could increase chlorophyll in all cultivars tested. The highest levels of chlorophyll a were present in the moderate shade level (n2), then decreased at the shelter level (n3) and increased again at high levels (n4). While on chlorophyll content b, it appears that shade increased chlorophyll b in all cultivars tested and this increase was linear to the increase of shade. The shade treatment may increase the anthocyanin content and the increase depending on the type of cultivar. Increased levels of anthocyanin highest due to shade occurred on Jangkobembe cultivar. The original level of anthocyanin on Jangkobembe cultivar averaged 0.096 mg g-1 increased to 2.487 mg g-1 or increased 26 fold. It is concluded that the shade had a significant effect on the chlorophyll and anthocyanin content.

  10. Estimating chlorophyll content of spartina alterniflora at leaf level using hyper-spectral data

    Science.gov (United States)

    Wang, Jiapeng; Shi, Runhe; Liu, Pudong; Zhang, Chao; Chen, Maosi

    2017-09-01

    Spartina alterniflora, one of most successful invasive species in the world, was firstly introduced to China in 1979 to accelerate sedimentation and land formation via so-called "ecological engineering", and it is now widely distributed in coastal saltmarshes in China. A key question is how to retrieve chlorophyll content to reflect growth status, which has important implication of potential invasiveness. In this work, an estimation model of chlorophyll content of S. alterniflora was developed based on hyper-spectral data in the Dongtan Wetland, Yangtze Estuary, China. The spectral reflectance of S. alterniflora leaves and their corresponding chlorophyll contents were measured, and then the correlation analysis and regression (i.e., linear, logarithmic, quadratic, power and exponential regression) method were established. The spectral reflectance was transformed and the feature parameters (i.e., "san bian", "lv feng" and "hong gu") were extracted to retrieve the chlorophyll content of S. alterniflora . The results showed that these parameters had a large correlation coefficient with chlorophyll content. On the basis of the correlation coefficient, mathematical models were established, and the models of power and exponential based on SDb had the least RMSE and larger R2 , which had a good performance regarding the inversion of chlorophyll content of S. alterniflora.

  11. Mutagentic effects of aerospace on Poa pratensis L.. Pt.2: Photosynthesis characters and chlorophyll contents

    International Nuclear Information System (INIS)

    Han Lei; Sun Zhenyuan; Ju Guansheng; Qian Yongqiang; Li Yinfeng; Peng Zhenhua

    2005-01-01

    The dry seeds of Poa pratensis L. 'Nassau' were carried by 'Shenzhou No.3' and three mutants were screened based on presentational characters from the treated plants and asexual reproduced them as PM 1 , PM 2 and PM 3 . The effects of the space environment on the photosynthesis characters and the contents of chlorophyll of the plants were investigated. Compared to CK, the contents of the chlorophyll a and b were reduced both in PM 1 and PM 3 , and the photosynthetic ability also decreased. The content of the chlorophyll in PM 2 increased greatly, but the ratio of the chlorophyll a/b was reduced, and the apparent quantum efficiency and the photosynthetic ability also decreased. The approximately CO 2 saturation point of the three mutants were higher than CK, but the CO 2 compensation points showed no difference between the mutants and CK. The carboxylation efficiency was PM 2 3 1 . (authors)

  12. Stomata character and chlorophyll content of tomato in response to Zn application under drought condition

    Science.gov (United States)

    Sakya, A. T.; Sulistyaningsih, E.; Indradewa, D.; Purwanto, B. H.

    2018-03-01

    This experiment was performed in order to evaluate the effects of Zn application under drought condition on tomato, especially its chlorophyll content and stomata character. This experiment was arranged in factorial using randomized complete block design with three replications. The treatment consisted of the Zn application method, namely: soil and foliar, the Zn dosage, namely: 0, 40 and 60 mg ZnSO4 kg-1 soil and two cultivars of tomato, namely: ‘Tyrana’ F1 and ‘Permata’ F1. The stress condition was induced by watering every 12 days of 3 weeks after transplanting until harvesting. The results showed that the soil with a Zn application under drought conditions increased the aperture stomata, chlorophyll b and chlorophyll a/b ratio. The response of stomata character, chlorophyll a and total chlorophyll in both cultivars was similar.

  13. Dustfall Effect on Hyperspectral Inversion of Chlorophyll Content - a Laboratory Experiment

    Science.gov (United States)

    Chen, Yuteng; Ma, Baodong; Li, Xuexin; Zhang, Song; Wu, Lixin

    2018-04-01

    Dust pollution is serious in many areas of China. It is of great significance to estimate chlorophyll content of vegetation accurately by hyperspectral remote sensing for assessing the vegetation growth status and monitoring the ecological environment in dusty areas. By using selected vegetation indices including Medium Resolution Imaging Spectrometer Terrestrial Chlorophyll Index (MTCI) Double Difference Index (DD) and Red Edge Position Index (REP), chlorophyll inversion models were built to study the accuracy of hyperspectral inversion of chlorophyll content based on a laboratory experiment. The results show that: (1) REP exponential model has the most stable accuracy for inversion of chlorophyll content in dusty environment. When dustfall amount is less than 80 g/m2, the inversion accuracy based on REP is stable with the variation of dustfall amount. When dustfall amount is greater than 80 g/m2, the inversion accuracy is slightly fluctuation. (2) Inversion accuracy of DD is worst among three models. (3) MTCI logarithm model has high inversion accuracy when dustfall amount is less than 80 g/m2; When dustfall amount is greater than 80 g/m2, inversion accuracy decreases regularly and inversion accuracy of modified MTCI (mMTCI) increases significantly. The results provide experimental basis and theoretical reference for hyperspectral remote sensing inversion of chlorophyll content.

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

    Science.gov (United States)

    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.

  15. Effect of drought stress on yield, proline and chlorophyll contents in three chickpea cultivars

    NARCIS (Netherlands)

    Mafakheri, A.; Siosemardeh, A.; Bahramnejad, B.; Struik, P.C.; Sohrabi, Y.

    2010-01-01

    Drought stress is one of the major abiotic stresses in agriculture worldwide. This study was carried out to investigate the effect of drought stress on proline content, chlorophyll content, photosynthesis and transpiration, stomatal conductance and yield characteristics in three varieties of

  16. Effect of gamma radiation on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa

    International Nuclear Information System (INIS)

    Martin Moreno, C.; Fernandez Gonzalez, J.

    1983-01-01

    The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa has been studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and 5000 Gy, being, at first b chlorophyll affected to a greater extent than a chlorophyll. Net photosynthesis and respiration decline throughout the time of the observation after irradiation, this depressing effect being much more remarkable for the first one. Met photosynthesis inhibition levels of about 30% are got only five hours post irradiation at a dose of 5000 Gy. Radio estimation by low doses, although obtained in some cases for tho 10 Gy dose, has not been statistically confirmed. (Author) 23 refs

  17. Effect of Drought Stress and Methanol on Chlorophyll Parameters, Chlorophyll Content and Relative Water Content of Soybean (Glycine max L., var. L 17

    Directory of Open Access Journals (Sweden)

    M Mirakhori

    2011-01-01

    Full Text Available Abstract In order to investigate the effects of methanol application on some physiological properties of soybean under low water stress, a factorial experiment was conducted at Research Field of Faculty of Agriculture and Natural Resources, Islamic Azad University-Karaj Branch, Karaj, Iran, during 2008, based on a randomized complete block design with three replications. The first factor was consisted of different levels of methanol equal to 0 (control, 7, 14, 21, 28 and 35 volumetric percentage (v/v, which were used as foliar applications at three times during growth season of soybean, with 15 days intervals. The second factor was water stress conditions in two levels, based on depletion of 40 and 70% of available soil moisture. Some traits such as grain yield (GY, relative water content (RWC, chlorophyll fluorescence parameters, and chlorophyll content were measured, one day before and after the third methanol application. Results showed that chlorophyll content (Chl, GY, electrolytes leakage (EL at second sampling, photochemical capacity of PSII (Fv/Fm, maximum and variable fluorescence (Fm and FV, respectively were affected by water stress significantly (p

  18. Plant leaf chlorophyll content retrieval based on a field imaging spectroscopy system.

    Science.gov (United States)

    Liu, Bo; Yue, Yue-Min; Li, Ru; Shen, Wen-Jing; Wang, Ke-Lin

    2014-10-23

    A field imaging spectrometer system (FISS; 380-870 nm and 344 bands) was designed for agriculture applications. In this study, FISS was used to gather spectral information from soybean leaves. The chlorophyll content was retrieved using a multiple linear regression (MLR), partial least squares (PLS) regression and support vector machine (SVM) regression. Our objective was to verify the performance of FISS in a quantitative spectral analysis through the estimation of chlorophyll content and to determine a proper quantitative spectral analysis method for processing FISS data. The results revealed that the derivative reflectance was a more sensitive indicator of chlorophyll content and could extract content information more efficiently than the spectral reflectance, which is more significant for FISS data compared to ASD (analytical spectral devices) data, reducing the corresponding RMSE (root mean squared error) by 3.3%-35.6%. Compared with the spectral features, the regression methods had smaller effects on the retrieval accuracy. A multivariate linear model could be the ideal model to retrieve chlorophyll information with a small number of significant wavelengths used. The smallest RMSE of the chlorophyll content retrieved using FISS data was 0.201 mg/g, a relative reduction of more than 30% compared with the RMSE based on a non-imaging ASD spectrometer, which represents a high estimation accuracy compared with the mean chlorophyll content of the sampled leaves (4.05 mg/g). Our study indicates that FISS could obtain both spectral and spatial detailed information of high quality. Its image-spectrum-in-one merit promotes the good performance of FISS in quantitative spectral analyses, and it can potentially be widely used in the agricultural sector.

  19. THE EFFECT OF ORGANIC SEDIMENT CONTENT ON CORAL DIVERSITY IN KARIMUNJAWA ISLAND, INDONESIA

    Directory of Open Access Journals (Sweden)

    Fajar Nugroho

    2018-06-01

    Full Text Available Coral reef now are under threats due to sedimentation. Fatal effect of organic rich sediment, leading corals mortality. Therefore, the study was conducted to investigate effect of organic sediment content to the coral diversity in Karimunjawa Island, Central Java, Indonesia. Field data was conducted at 6 locations.  Three sediment traps were deployed at each sites to measure organic sediment content. Twenty replicated quadrant transects were used to estimate coral density and coral diversity. Analysis of variance (ANOVA was used to examine the differences of organic sediment content in each station. The linear regression was used to assess the relationship between organic sediment content and coral diversity. Our field result demonstrated that sediment content significantly different between sites with value range from 0.42 mg/800 ml - 1.32 mg/800 ml. Based on the Simson’s Diversity Index, the highest coral diversity found at Alang-alang as site with low sedimentation while the lowest coral diversity was found at Legon Lele as site with high sedimentation. The study shown significant negative correlation between organic sediment content and coral diversity with the coefficient of regression 0.68. This study convinces that disturbance on coral reefs might affect coral diversity in Karimunjawa Island, in addition to other factors such as the influence of human activities, natural disruption and climate change. Keywords: sedimentation, organic, coral, diversity, Karimunjawa

  20. Using near infrared spectrum analysis to predict water and chlorophyll content in tomato leaves

    Science.gov (United States)

    Jiang, Huanyu; Ying, Yibin; Liu, Yande

    2004-11-01

    In this study, we developed a nondestructive way to analyze water and chlorophyll content in tomato leaves. A total of 200 leaves were collected as experimental materials, 120 of them were used to form a calibration data set. Drying chest, SPAD meter and NIR spectrometer were used to get water content, chlorophyll content and spectrums of tomato leaves respectively. The Fourier Transform Infrared (FTNIR) method with a smart Near-IR Updrift was used to test spectrums, and partial least squares (PLS) technique was used to analyze the data we get by normal experimentation and near infrared spectrometer, set up a calibration model to predict the leaf water and chlorophyll content based on the characteristics of diffuse reflectance spectrums of tomato leaves. Three different mathematical treatments were used in spectrums processing: different wavelength range, different smoothing points, first and second derivative. We can get best prediction model when we select full range (800-2500nm), 3 points for spectrums smoothing and spectrums by baseline correction, the best model of chlorophyll content has a root mean square error of prediction (RMSEP) of 8.16 and a calibration correlation coefficient (R2) value of 0.89452 and the best model of water content has a root mean square error of prediction (RMSEP) of 0.0214 and a calibration correlation coefficient (R2) value of 0.91043.

  1. Direct effect of acid rain on leaf chlorophyll content of terrestrial plants in China.

    Science.gov (United States)

    Du, Enzai; Dong, Dan; Zeng, Xuetong; Sun, Zhengzhong; Jiang, Xiaofei; de Vries, Wim

    2017-12-15

    Anthropogenic emissions of acid precursors in China have resulted in widespread acid rain since the 1980s. Although efforts have been made to assess the indirect, soil mediated ecological effects of acid rain, a systematic assessment of the direct foliage injury by acid rain across terrestrial plants is lacking. Leaf chlorophyll content is an important indicator of direct foliage damage and strongly related to plant productivity. We synthesized data from published literature on experiments of simulated acid rain, by directly exposing plants to acid solutions with varying pH levels, to assess the direct effect of acid rain on leaf chlorophyll content across 67 terrestrial plants in China. Our results indicate that acid rain substantially reduces leaf chlorophyll content by 6.71% per pH unit across the recorded plant species. The direct reduction of leaf chlorophyll content due to acid rain exposure showed no significant difference across calcicole, ubiquist or calcifuge species, implying that soil acidity preference does not influence the sensitivity to leaf injury by acid rain. On average, the direct effects of acid rain on leaf chlorophyll on trees, shrubs and herbs were comparable. The effects, however varied across functional groups and economic use types. Specifically, leaf chlorophyll content of deciduous species was more sensitive to acid rain in comparison to evergreen species. Moreover, vegetables and fruit trees were more sensitive to acid rain than other economically used plants. Our findings imply a potential production reduction and economic loss due to the direct foliage damage by acid rain. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Principal Component Analysis of Chlorophyll Content in Tobacco, Bean and Petunia Plants Exposed to Different Tropospheric Ozone Concentrations

    Science.gov (United States)

    Borowiak, Klaudia; Zbierska, Janina; Budka, Anna; Kayzer, Dariusz

    2014-06-01

    Three plant species were assessed in this study - ozone-sensitive and -resistant tobacco, ozone-sensitive petunia and bean. Plants were exposed to ambient air conditions for several weeks in two sites differing in tropospheric ozone concentrations in the growing season of 2009. Every week chlorophyll contents were analysed. Cumulative ozone effects on the chlorophyll content in relation to other meteorological parameters were evaluated using principal component analysis, while the relation between certain days of measurements of the plants were analysed using multivariate analysis of variance. Results revealed variability between plant species response. However, some similarities were noted. Positive relations of all chlorophyll forms to cumulative ozone concentration (AOT 40) were found for all the plant species that were examined. The chlorophyll b/a ratio revealed an opposite position to ozone concentration only in the ozone-resistant tobacco cultivar. In all the plant species the highest average chlorophyll content was noted after the 7th day of the experiment. Afterwards, the plants usually revealed various responses. Ozone-sensitive tobacco revealed decrease of chlorophyll content, and after few weeks of decline again an increase was observed. Probably, due to the accommodation for the stress factor. While during first three weeks relatively high levels of chlorophyll contents were noted in ozone-resistant tobacco. Petunia revealed a slow decrease of chlorophyll content and the lowest values at the end of the experiment. A comparison between the plant species revealed the highest level of chlorophyll contents in ozone-resistant tobacco.

  3. Effects of woody elements on simulated canopy reflectance: implications for forest chlorophyll content retrieval

    NARCIS (Netherlands)

    Verrelst, J.; Schaepman, M.E.; Malenovsky, Z.; Clevers, J.G.P.W.

    2010-01-01

    An important bio-indicator of actual plant health status, the foliar content of chlorophyll a and b (Cab), can be estimated using imaging spectroscopy. For forest canopies, however, the relationship between the spectral response and leaf chemistry is confounded by factors such as background (e.g.

  4. Chlorophyll content of Plešné Lake phytoplankton cells studied with image analysis

    Czech Academy of Sciences Publication Activity Database

    Nedoma, Jiří; Nedbalová, Linda

    2006-01-01

    Roč. 61, Suppl. 20 (2006), S491-S498 ISSN 0006-3088 Grant - others:MSMT(CZ) 0021620828 Institutional research plan: CEZ:AV0Z60170517; CEZ:AV0Z60050516 Keywords : cellular chlorophyll content * image analysis * vertical profile Subject RIV: EH - Ecology, Behaviour Impact factor: 0.213, year: 2006

  5. Spatial variability of chlorophyll and nitrogen content of rice from hyperspectral imagery

    Science.gov (United States)

    Moharana, Shreedevi; Dutta, Subashisa

    2016-12-01

    Chlorophyll and nitrogen are the most essential parameters for paddy crop growth. Spectroradiometric measurements were collected at canopy level during critical growth period of rice. Chemical analysis was performed to quantify the total leaf content. By exploiting the ground based measurements, regression models were established for chlorophyll and nitrogen aimed indices with their corresponding crop growth variables. Vegetation index models were developed for mapping these parameters from Hyperion imagery in an agriculture system. It was inferred that the present Simple Ratio (SR) and Leaf Nitrogen Concentration (LNC) indices, which followed a linear and nonlinear relationship respectively, were completely different from published Tian et al. (2011). The nitrogen content varied widely from 1 to 4% and only 2 to 3% for paddy crop using present modified index models and Tian et al. (2011) respectively. The modified LNC index model performed better than the established Tian et al. (2011) model as far as estimated nitrogen content from Hyperion imagery was concerned. Furthermore, within the observed chlorophyll range obtained from the studied rice varieties grown in the rice agriculture system, the index models (LNC, OASVI, Gitelson, mSR and MTCI) performed well in the spatial distribution of rice chlorophyll content from Hyperion imagery. Spatial distribution of total chlorophyll content varied widely from 1.77 to 5.81 mg/g (LNC), 3.0 to 13 mg/g (OASVI), 0.5 to 10.43 mg/g (Gitelson), 2.18 to 10.61 mg/g (mSR) and 2.90 to 5.40 mg/g (MTCI). The spatial information of these parameters will help in proper nutrient management, yield forecasting, and will serve as inputs for crop growth and forecasting models for a precision rice agriculture system.

  6. Relationship between color (instrumental and visual) and chlorophyll contents in soybean seeds during ripening.

    Science.gov (United States)

    Sinnecker, Patrícia; Gomes, M Salete O; Arêas, José A G; Lanfer-Marquez, Ursula M

    2002-07-03

    The correlation between chlorophyll content and quantitative color parameters was investigated in order to find an indirect method for predicting green pigment in ripening soybean seeds. Five Brazilian soybean varieties harvested at different maturity stages (R(6) to R(8) according to the scale of Fehr & Caviness) and dried under two conditions (in oven at 40 degrees C with circulating air and at ambient temperature around 25 degrees C) were analyzed in two consecutive years. The slow-dried seeds at 25 degrees C lost chlorophyll faster, whereas drying at 40 degrees C did not result in yellowing of seeds. High and significant linear correlations between a value and total chlorophyll were obtained over the whole maturation period and on both conditions of drying. From an industrial point of view it appears that a value, obtained by the CIE-L*a*b* method, seems to be a good tool to be applied for quality control and classifying soybean seeds for different purposes.

  7. Evaluating the capabilities of vegetation spectral indices on chlorophyll content estimation at Sentinel-2 spectral resolutions

    Science.gov (United States)

    Sun, Qi; Jiao, Quanjun; Dai, Huayang

    2018-03-01

    Chlorophyll is an important pigment in green plants for photosynthesis and obtaining the energy for growth and development. The rapid, nondestructive and accurate estimation of chlorophyll content is significant for understanding the crops growth, monitoring the disease and insect, and assessing the yield of crops. Sentinel-2 equipped with the Multi-Spectral Instrument (MSI), which will provide images with high spatial, spectral and temporal resolution. It covers the VNIR/SWIR spectral region in 13 bands and incorporates two new spectral bands in the red-edge region and a spatial resolution of 20nm, which can be used to derive vegetation indices using red-edge bands. In this paper, we will focus on assessing the potential of vegetation spectral indices for retrieving chlorophyll content from Sentinel-2 at different angles. Subsequently, we used in-situ spectral data and Sentinel-2 data to test the relationship between VIs and chlorophyll content. The REP, MTCI, CIred-edge, CIgreen, Macc01, TCARI/OSAVI [705,750], NDRE1 and NDRE2 were calculated. NDRE2 index displays a strongly similar result for hyperspectral and simulated Sentinel-2 spectral bands (R2 =0.53, R2 =0.51, for hyperspectral and Sentinel-2, respectively). At different observation angles, NDRE2 has the smallest difference in performance (R2 = 0.51, R2 =0.64, at 0° and 15° , respectively).

  8. Remote estimation of nitrogen and chlorophyll contents in maize at leaf and canopy levels

    Science.gov (United States)

    Schlemmer, M.; Gitelson, A.; Schepers, J.; Ferguson, R.; Peng, Y.; Shanahan, J.; Rundquist, D.

    2013-12-01

    Leaf and canopy nitrogen (N) status relates strongly to leaf and canopy chlorophyll (Chl) content. Remote sensing is a tool that has the potential to assess N content at leaf, plant, field, regional and global scales. In this study, remote sensing techniques were applied to estimate N and Chl contents of irrigated maize (Zea mays L.) fertilized at five N rates. Leaf N and Chl contents were determined using the red-edge chlorophyll index with R2 of 0.74 and 0.94, respectively. Results showed that at the canopy level, Chl and N contents can be accurately retrieved using green and red-edge Chl indices using near infrared (780-800 nm) and either green (540-560 nm) or red-edge (730-750 nm) spectral bands. Spectral bands that were found optimal for Chl and N estimations coincide well with the red-edge band of the MSI sensor onboard the near future Sentinel-2 satellite. The coefficient of determination for the relationships between the red-edge chlorophyll index, simulated in Sentinel-2 bands, and Chl and N content was 0.90 and 0.87, respectively.

  9. Effects of Cd2+ on chlorophyll content in flag and grain yield of wheats

    International Nuclear Information System (INIS)

    Zhu Zhiyong; Li Youjun; Liu Yingjie; Duan Youqiang; Li Qiang; Hao Yufen; Guo Jia

    2011-01-01

    A field experiment was conducted with wheat cultivars Luohan 6 and Yumai 18 to investigate the effects of Cd 2+ stress on chlorophyll contents in flag leaves, flag leave area, thousand kernel weight, kernel filling velocity and yield of wheat. Results indicated that, under low Cd 2+ stress (10 mg/kg), the average contents of chlorophyll a + b of Luohan 6 reduced by 1.6%, however, its average area of flag leave and yield increased by 3.8% and 1.6%, respectively. At the same time, the average content of chlorophyll a + b, area of flag leave yield of Yumai 18 reduced 8.0%, 9.6% and 5.4%. Under high Cd 2+ stress (100 mg/kg), the average contents of chlorophyll a + b, areas of flag leaves and yields of Luohan 6 and Yumai 18 reduced by 29.2% and 30.5%, 6.3% and 17.4%, 16.7% and 36.7%, respectively. The results demonstrated that Cd 2+ restrained synthesis and accumulation of chlorophyll and its components. This study even showed that within a range of Cd 2+ concentration could promote the growth of flag leaves, and it also had an equal positive effect on yield of wheat if the Cd 2+ concentration in grains were not out of limit. The growth of flag leave and yield of wheat would be limited when Cd 2+ concentration exceed that range. Overall, Yumai 18 bore more poison from Cd 2+ than Luohan 6. (authors)

  10. The effect of High Pressure and High Temperature processing on carotenoids and chlorophylls content in some vegetables.

    Science.gov (United States)

    Sánchez, Celia; Baranda, Ana Beatriz; Martínez de Marañón, Iñigo

    2014-11-15

    The effect of High Pressure (HP) and High Pressure High Temperature (HPHT) processing on carotenoid and chlorophyll content of six vegetables was evaluated. In general, carotenoid content was not significantly influenced by HP or HPHT treatments (625 MPa; 5 min; 20, 70 and 117 °C). Regarding chlorophylls, HP treatment caused no degradation or slight increases, while HPHT processes degraded both chlorophylls. Chlorophyll b was more stable than chlorophyll a at 70 °C, but both of them were highly degraded at 117 °C. HPHT treatment at 117 °C provided products with a good retention of carotenoids and colour in the case of red vegetables. Even though the carotenoids also remained in the green vegetables, their chlorophylls and therefore their colour were so affected that milder temperatures need to be applied. As an industrial scale equipment was used, results will be useful for future industrial implementation of this technology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Effects of sodium pentaborate pentahydrate exposure on Chlorella vulgaris growth, chlorophyll content, and enzyme activities.

    Science.gov (United States)

    Chen, Xueqing; Pei, Yuansheng

    2016-10-01

    Sodium pentaborate pentahydrate (SPP) is a rare mineral. In this study, SPP was synthesized from boric acid and borax through low-temperature crystallization, and its effects on the growth of the alga, Chlorella vulgaris (C. vulgaris) were assessed. The newly synthesized SPP was characterized by chemical analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, and differential thermal analysis. The changes in C. vulgaris growth, chlorophyll content, and enzyme activities upon exposure to SPP for 168h were evaluated. Results showed that SPP treatment was detrimental to C. vulgaris growth during the first 24-120h of exposure. The harmful effects, however, diminished over time (168h), even at an effective medium concentration of 226.37mg BL(-1) (the concentration of boron applied per liter of culture medium). A similar trend was observed for chlorophyll content (chlorophyll a and b) and indicated that the photosynthesis of C. vulgaris was not affected and that high levels of SPP may even promote chlorophyll synthesis. Superoxide dismutase and catalase activities of C. vulgaris increased during 24-120h exposure to SPP, but these activities gradually decreased as culture time progressed. In other words, the initial detrimental effects of synthetic SPP on C. vulgaris were temporary and reversible. This research provides a scientific basis for applications of SPP in the environment. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Involvement of Arabidopsis glutaredoxin S14 in the maintenance of chlorophyll content.

    Science.gov (United States)

    Rey, Pascal; Becuwe, Noëlle; Tourrette, Sébastien; Rouhier, Nicolas

    2017-10-01

    Plant class-II glutaredoxins (GRXs) are oxidoreductases carrying a CGFS active site signature and are able to bind iron-sulfur clusters in vitro. In order to explore the physiological functions of the 2 plastidial class-II isoforms, GRXS14 and GRXS16, we generated knockdown and overexpression Arabidopsis thaliana lines and characterized their phenotypes using physiological and biochemical approaches. Plants deficient in one GRX did not display any growth defect, whereas the growth of plants lacking both was slowed. Plants overexpressing GRXS14 exhibited reduced chlorophyll content in control, high-light, and high-salt conditions. However, when exposed to prolonged darkness, plants lacking GRXS14 showed accelerated chlorophyll loss compared to wild-type and overexpression lines. We observed that the GRXS14 abundance and the proportion of reduced form were modified in wild type upon darkness and high salt. The dark treatment also resulted in decreased abundance of proteins involved in the maturation of iron-sulfur proteins. We propose that the phenotype of GRXS14-modified lines results from its participation in the control of chlorophyll content in relation with light and osmotic conditions, possibly through a dual action in regulating the redox status of biosynthetic enzymes and contributing to the biogenesis of iron-sulfur clusters, which are essential cofactors in chlorophyll metabolism. © 2017 John Wiley & Sons Ltd.

  13. [Development and test of a wheat chlorophyll, nitrogen and water content meter].

    Science.gov (United States)

    Yu, Bo; Sun, Ming; Han, Shu-Qing; Xia, Jin-Wen

    2011-08-01

    A portable meter was developed which can detect chlorophyll, nitrogen and moisture content of wheat leaf simultaneously, and can supply enough data for guiding fertilization and irrigation. This meter is composed of light path and electronic circuit. And this meter uses 660, 940 and 1450 nm LED together with narrow band filters as the active light source. The hardware circuit consists of micro-controller, LED drive circuit, detector, communication circuit, keyboard and LCD circuit. The meter was tested in the field and performed well with good repeatability and accuracy. The relative errors of chlorophyll and nitrogen test were about 10%, relative error for water content was 4%. The coefficients of variation of the three indices were all below 1.5%. All of these prove that the meter can be applied under the field condition to guide the wheat production.

  14. The effect of salt stress on growth, chlorophyll content, proline and nutrient accumulation, and k/na ratio in walnut

    International Nuclear Information System (INIS)

    Akca, Y.; Samsunlu, E

    2012-01-01

    The effects of irrigation water salinity on growth, chlorophyll contents, proline and nutrients accumulation and K/Na ratio in three walnut cultivars was investigated. Three irrigation water salinity levels with electrical conductivities of 1,5, 3, and 5.0 dS/m and tap water as a control treatment were used in a randomized design with four replications. Irrigation practices were realized by considering the weight of each pot. Sodium, clor, proline, K/Na and Ca/Na ratio of leaf were increased under salinity conditions. But growth of plant and chlorophyll a, chlorophyll b content were decreased under saline condition. There were significant differences between in irrigation water salinity levels in proline and chlorophyll a, chlorophyll b, Na content. But there were not any significant differences in LRWC (%). Results showed that, regarding fresh shoot weight, dry shoot and root weight, there were significant differences between cultivars, but chlorophyll a, chlorophyll b, total chlorophyll, proline accumulation and leaf relative water content (LRWC) there weren't any significant differences between cultivars. Kaman 1 and Bilecik walnut cultivars showed higher accumulation of proline than Kaman 5 but was not observed significant difference between them. (author)

  15. Pigment content (chlorophyll and carotenoids) in 37 species of trees and shrubs in northeastern mexico during summer season

    International Nuclear Information System (INIS)

    Rodriguez, H.G.; Avendano, E.; Maiti, R.; Kumari, C.A.

    2017-01-01

    Plant pigments play an important role in plant assimilatory systems and plant growth. A study was undertaken to determine chlorophyll a, chlorophyll b and carotenoids contents of thirty seven species of trees and shrubs in summer season, in Linares, northeastern Mexico. Large variations were observed in the contents of chlorophyll (a, b and total) and also carotenoids among species. Chlorophyll a was minimum (around 0.6 mg) in Leucophyllum frutescens and Acacia berlandieri and maximum (1.8 mg) in Ebenopsis ebano. Chlorophyll b was minimum in Forestiera angustifolia, Acacia berlandieri, and Leucophyllum frutescens (0.1 to 0.2 mg), while Ebenopsis ebano contained maximum (0.4 mg). Carotenoids content was minimum (around 0.2 mg) in Leucophyllum frutescens, Acacia berlandieri and Parkinsonia aculeata and others but maximum value (around 0.6 mg) was observed in Berberis trifoliata. Total chlorophyll (a+b) content minimum values (around 0.6 mg) were recorded in Leucophyllum frutescens, Forestiera angustifolia, Croton suaveolens and Acacia berlandieri, while maximum value (around 2 mg) was obtained in Ebenopsis ebano. Maximum values of chlorophyll (a:b) ratio (around 7) was seen in Forestiera angustifolia, Salix lasiolepis followed by Diospyros texana (around 6). The ratio of total chlorophyll/carotenoids was maximum in Parkinsonia aculeata (nearing 8), while minimum value was obtained in Berberis trifoliata (around 2). (author)

  16. Photosynthesis rate, chlorophyll content and initial development of physic nut without micronutrient fertilization

    Directory of Open Access Journals (Sweden)

    Elcio Ferreira dos Santos

    2013-10-01

    Full Text Available Few studies in Brazil have addressed the need for micronutrients of physic nut focusing on physiological responses, especially in terms of photosynthesis. The objective of this study was to evaluate the effects of omission of boron (B, copper (Cu, iron (Fe, manganese (Mn and zinc (Zn on Jatropha curcas L.. The experimental design was a randomized block with four replications. The treatments were complete solution (control and solution without B, Cu, Fe, Mn, and Zn. We evaluated the chlorophyll content (SPAD units, photosynthetic rate, dry matter production and accumulation of micronutrients in plants, resulting from different treatments. The first signs of deficiency were observed for Fe and B, followed by Mn and Zn, while no symptoms were observed for Cu deficiency. The micronutrient omission reduced the dry matter yield, chlorophyll content and photosynthetic rate of the plants differently for each omitted nutrient. It was, however, the omission of Fe that most affected the development of this species in all parameters evaluated. The treatments negatively affected the chlorophyll content, evaluated in SPAD units, and the photosynthetic rate, except for the omission of B. However this result was probably due to the concentration effect, since there was a significant reduction in the dry matter production of B-deficient plants.

  17. EFFECT OF ARSENIC ON DRY WEIGHT AND RELATIVE CHLOROPHYLL CONTENT IN GREENINGMAIZE AND SUNFLOWER TISSUES

    Directory of Open Access Journals (Sweden)

    Szilvia Várallyay

    2015-02-01

    Full Text Available Arsenic is one of the most toxic elements that can be found in the environment. Excessive uptake of arsenic may cause physiological changes in plants. The aim of the study was to investigate the effect of different arsenic treatments on relative chlorophyll content and dry weight of shoot and root of maize and sunflower in the early phases of plant development. Seedlings were grown in climatic room in nutrient solution under strictly regulated environmental conditions. The plants were exposed to 3, 10 and 30 mg kg-1arsenic, whereas there was no arsenic treatment on the control plants. We applied arsenic in the form of arsenite (NaAsO2 and arsenate (KH2AsO4, respectively. After 14 days of arsenic treatments, changes in relative chlorophyll content and dry weight of maize shoots and roots were recorded. In the case of sunflower these physiological parameters were measured after 21 day. The applied arsenic decreased the relative chlorophyll content of maize and sunflower leaves, especially at concentration of30 mg kg-1. The increasing amount of As treatment were resulted the lower weight of the experimental plants, which was more considerable in the case of the roots. The results indicate that the sunflower plants is more sensitive to arsenic toxicity than maize plants and all data demonstrate that the As(III is more toxic to these crop plants than the As(V.

  18. Effect of crude oil contamination on the chlorophyll content and morpho-anatomy of Cyperus brevifolius (Rottb.) Hassk.

    Science.gov (United States)

    Baruah, Plabita; Saikia, Rashmi Rekha; Baruah, Partha Pratim; Deka, Suresh

    2014-11-01

    Chlorophyll plays a pivotal role in the plant physiology and its productivity. Cultivation of plants in crude oil contaminated soil has a great impact on the synthesis of chlorophyll pigment. Morpho-anatomy of the experimental plant also shows structural deformation in higher concentrations. Keeping this in mind, a laboratory investigation has been carried out to study the effect of crude oil on chlorophyll content and morpho-anatomy of Cyperus brevifolius plant. Fifteen-day-old seedling of the plant was planted in different concentrations of the crude oil mixed soil (i.e., 10,000, 20,000, 30,000, 40,000, and 50,000 ppm). A control setup was also maintained without adding crude oil. Results were recorded after 6 months of plantation. Investigation revealed that there is a great impact of crude oil contamination on chlorophyll content of the leaves of the experimental plant. It also showed that chlorophyll a, chlorophyll b, and total chlorophyll content of leaves grown in different concentrations of crude oil were found to be lower than those of the control plant. Further, results also demonstrated that chlorophyll content was lowest in the treatment that received maximum dose of crude oil. It also showed that chlorophyll content was decreased with increased concentration of crude oil. Results also demonstrated that there was a reduction in plant shoot and root biomass with the increase of crude oil concentration. Results also revealed that the shoot biomass is higher than root biomass. Morphology and anatomy of the experimental plant also show structural deformation in higher concentrations. Accumulation of crude oil on the cuticle of the transverse section of the leaves and shoot forms a thick dark layer. Estimation of the level of pollution in an environment due to oil spill is possible by the in-depth study of the harmful effects of oil on the morphology and anatomy and chlorophyll content of the plants grown in that particular environment.

  19. Leaf Surface Effects on Retrieving Chlorophyll Content from Hyperspectral Remote Sensing

    Science.gov (United States)

    Qiu, Feng; Chen, JingMing; Ju, Weimin; Wang, Jun; Zhang, Qian

    2017-04-01

    Light reflected directly from the leaf surface without entering the surface layer is not influenced by leaf internal biochemical content. Leaf surface reflectance varies from leaf to leaf due to differences in the surface roughness features and is relatively more important in strong absorption spectral regions. Therefore it introduces dispersion of data points in the relationship between biochemical concentration and reflectance (especially in the visible region). Separation of surface from total leaf reflection is important to improve the link between leaf pigments content and remote sensing data. This study aims to estimate leaf surface reflectance from hyperspectral remote sensing data and retrieve chlorophyll content by inverting a modified PROSPECT model. Considering leaf surface reflectance is almost the same in the visible and near infrared spectral regions, a surface layer with a reflectance independent of wavelength but varying from leaf to leaf was added to the PROSPECT model. The specific absorption coefficients of pigments were recalibrated. Then the modified model was inverted on independent datasets to check the performance of the model in predicting the chlorophyll content. Results show that differences in estimated surface layer reflectance of various species are noticeable. Surface reflectance of leaves with epicuticular waxes and trichomes is usually higher than other samples. Reconstruction of leaf reflectance and transmittance in the 400-1000 nm wavelength region using the modified PROSPECT model is excellent with low root mean square error (RMSE) and bias. Improvements for samples with high surface reflectance (e.g. maize) are significant, especially for high pigment leaves. Moreover, chlorophyll retrieved from inversion of the modified model is consequently improved (RMSE from 5.9-13.3 ug/cm2 with mean value 8.1 ug/cm2, while mean correlation coefficient is 0.90) compared to results of PROSPECT-5 (RMSE from 9.6-20.2 ug/cm2 with mean value 13

  20. Responses of wild husk tomato, Physalis angulata L. to growth regulators and gamma rays on chlorophyll content and fruit yield

    International Nuclear Information System (INIS)

    Raghava, R.P.; Raghava, Nisha

    1994-01-01

    Effect of different growth regulators and gamma rays on the total chlorophyll content and fruit yield were studied in wild species of husk tomato and concluded that indole-3-acetic acid (IAA) 200 and kinetin (KIN) 10 ppm showed remarkable enhancement in both total chlorophyll content and fruit yield, while maleic hydrazide (MH) 100, 200 ppm and coumarin (COU) in all the treatments enhanced total chlorophyll content. Gamma ray treatments significantly enhanced both the parameters. Amongst all the treatments maximum fruit yield was in 20 kR of gamma rays. (author). 31 refs., 1 tab

  1. Growth, chlorophyll content and combined output value in eggplant/garlic relay intercropping systems

    International Nuclear Information System (INIS)

    Wang, M.; Wu, C.; Yang, F.; Cheng, Z.; Meng, H.

    2015-01-01

    A plastic tunnel experiment was conducted to investigate the effect of eggplant/garlic relay intercropping on the eggplant growth, chlorophyll content and combined output value in 2011 and 2012. The experimental design was randomized block with three replications consisting of eggplant monoculture (CK), eggplant relay intercropping with normal garlic (NG) and eggplant relay intercropping with green garlic (GG). It is showed that the eggplant stem in 2011 was first thicker then thinner in CK than NG, and it was always thicker in CK than GG; the plant height and stem diameter were both higher in relay intercropping treatments than CK in 2012. The chlorophyll content and chlorophyll a/b ratio were lower in NG compared with CK in most cases. In 2011, the eggplant yield and combined output value in GG were lower than CK, but in 2012, they were higher and the difference of combined output value between GG and CK was significant; for NG, they were always promoted both in 2011 and 2012. Different results between 2011 and 2012 may be due to the different time of green garlic uprooted in the spring. It is proved that uprooting green garlic before eggplant transplanting in 2012 was better to eggplant growth than uprooting them after eggplant transplanting in 2011. The conclusions are drawn that relay intercropping with normal or green garlic can improve the eggplant growth, increase the yield and the combined output value. As a result, eggplant/garlic relay intercropping systems may contribute to sustainable production of eggplant. (author)

  2. Fluctuations in coral health of four common inshore reef corals in response to seasonal and anthropogenic changes in water quality.

    Science.gov (United States)

    Browne, Nicola K; Tay, Jason K L; Low, Jeffrey; Larson, Ole; Todd, Peter A

    2015-04-01

    Environmental drivers of coral condition (maximum quantum yield, symbiont density, chlorophyll a content and coral skeletal growth rates) were assessed in the equatorial inshore coastal waters of Singapore, where the amplitude of seasonal variation is low, but anthropogenic influence is relatively high. Water quality variables (sediments, nutrients, trace metals, temperature, light) explained between 52 and 83% of the variation in coral condition, with sediments and light availability as key drivers of foliose corals (Merulina ampliata, Pachyseris speciosa), and temperature exerting a greater influence on a branching coral (Pocillopora damicornis). Seasonal reductions in water quality led to high chlorophyll a concentrations and maximum quantum yields in corals, but low growth rates. These marginal coral communities are potentially vulnerable to climate change, hence, we propose water quality thresholds for coral growth with the aim of mitigating both local and global environmental impacts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Hyperspectral and multispectral satellite sensors for mapping chlorophyll content in a Mediterranean Pinus sylvestris L. plantation

    Science.gov (United States)

    Navarro-Cerrillo, Rafael Mª; Trujillo, Jesus; de la Orden, Manuel Sánchez; Hernández-Clemente, Rocío

    2014-02-01

    A new generation of narrow-band hyperspectral remote sensing data offers an alternative to broad-band multispectral data for the estimation of vegetation chlorophyll content. This paper examines the potential of some of these sensors comparing red-edge and simple ratio indices to develop a rapid and cost-effective system for monitoring Mediterranean pine plantations in Spain. Chlorophyll content retrieval was analyzed with the red-edge R750/R710 index and the simple ratio R800/R560 index using the PROSPECT-5 leaf model and the Discrete Anisotropic Radiative Transfer (DART) and experimental approach. Five sensors were used: AHS, CHRIS/Proba, Hyperion, Landsat and QuickBird. The model simulation results obtained with synthetic spectra demonstrated the feasibility of estimating Ca + b content in conifers using the simple ratio R800/R560 index formulated with different full widths at half maximum (FWHM) at the leaf level. This index yielded a r2 = 0.69 for a FWHM of 30 nm and r2 = 0.55 for a FWHM of 70 nm. Experimental results compared the regression coefficients obtained with various multispectral and hyperspectral images with different spatial resolutions at the stand level. The strongest relationships where obtained using high-resolution hyperspectral images acquired with the AHS sensor (r2 = 0.65) while coarser spatial and spectral resolution images yielded a lower root mean square error (QuickBird r2 = 0.42; Landsat r2 = 0.48; Hyperion r2 = 0.56; CHRIS/Proba r2 = 0.57). This study shows the need to estimate chlorophyll content in forest plantations at the stand level with high spatial and spectral resolution sensors. Nevertheless, these results also show the accuracy obtained with medium-resolution sensors when monitoring physiological processes. Generating biochemical maps at the stand level could play a critical rule in the early detection of forest decline processes enabling their use in precision forestry.

  4. Non-destructive evaluation of chlorophyll content in quinoa and amaranth leaves by simple and multiple regression analysis of RGB image components

    DEFF Research Database (Denmark)

    Riccardi, M.; Mele, G.; Pulvento, C.

    2014-01-01

    Leaf chlorophyll content provides valuable information about physiological status of plants; it is directly linked to photosynthetic potential and primary production. In vitro assessment by wet chemical extraction is the standard method for leaf chlorophyll determination. This measurement is expe...

  5. Chlorophyll a and turbidity patterns over coral reefs systems of La Parguera Natural Reserve,Puerto Rico

    Directory of Open Access Journals (Sweden)

    Ernesto Otero

    2005-05-01

    Full Text Available Studies of temporal and spatial changes in phytoplankton biomass and turbidity provide essential information on coral reef ecosystem function and health.Fluctuation of phytoplankton biomass responds to several factors including nutrient inputs,both anthropogenic and natural,while turbidity is mostly affected by sediment resuspension or transport from terrestrial systems.These parameters can be used as sentinels of significant environmental factors "modifying "coral reef systems.A chlorophyll a concentration (Chl a and turbidity (Turbin situ logger was installed at 10 stations from June 4 to July 7,2003 in La Parguera Natural Reserve (Southwestern Puerto Ricoto assess short-term temporal and geographic variation in patterns of phytoplankton biomass and turbidity at pre-selected sites as part of an interdisciplinary long-term study.Average station Chl a variation was 0.17-1.12 µg l -1 and 0.2-23.4 NTU for Turb.Results indicate that the western near-coastal stations had higher levels of Turb and Chl a .The easternmost mid shelf station,Romero reef,was similar to coastal stations probably due to nutrient and suspended sediment inputs from a source external to our study area to the east,Guánica Bay.Comparisons between different sampling days indicate significant differences between days for most stations suggesting that one-time discrete sampling may not be representative of average water column conditions and illustrate the dynamic nature of coral reef systems.Further work is warranted to assess seasonal changes that integrate short-term (dailyvariability in both Turb and Chl a .Los estudios sobre cambios temporales y espaciales de biomasa fitoplanctónica y de urbidad, proveen información esencial sobre la función y salud de los sistemas arrecifales.Fluctuaciones de la biomasa de fitoplancton responden a factores como entradas de nutrientes de fuentes antropogénicas y/o naturales,mientras que la turbidez responde mayormente a la resuspensi

  6. Red Light Represses the Photophysiology of the Scleractinian Coral

    NARCIS (Netherlands)

    Wijgerde, T.; van Melis, A.; Silva, C.I.F.; Leal, M.C.; Vogels, L.; Mutter, C.; Osinga, R.

    2014-01-01

    Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced

  7. Changes in chlorophyll and polyphenols content in Camellia sinensis var. sinensis at different stage of leaf maturity

    Science.gov (United States)

    Prawira-Atmaja, M. I.; Shabri; Khomaini, H. S.; Maulana, H.; Harianto, S.; Rohdiana, D.

    2018-03-01

    Chlorophyll and polyphenols are chemical compound related to parameter quality of green tea. We studied the variation of chlorophyll and polyphenol in the development stage of tea leaves (bud, 1st, 2nd, 3rd, and 4th). Five clones of tea (Camelia sinensis var. sinensis) from Indonesia and a clone from Japan were used in this study. The results showed that total chlorophyll and total polyphenol content in bud between 1.59-2.15 mg/g (db) and 12.24-14.59% respectively. The concentration of chlorophyll increased significantly with developments stage of leaf while total polyphenol tended to decrease with leaf maturity. Pearson Correlation analysis showed that chlorophyll content was negatively correlated (r = -0.83; p = 0.05) with total polyphenol during developmental stage of tea leaves. Results suggests that five clones of tea from Indonesia have similar quality with tea clone from Japan in chlorophyll and polyphenol content. The present study also provides guidelines on application plucking standard to produce high quality of green tea.

  8. Effects of Light Intensity on Development and Chlorophyll Content in the Arabidopsis Mutant Plants with Defects in Photosynthesis

    Directory of Open Access Journals (Sweden)

    E.Yu. Garnik

    2015-12-01

    Full Text Available The developmental stages and adaptability to different light intensity (150 µmol*m-2*s-1 and 100 µmol*m-2*s-1 in Arabidopsis mutant lines with defects of photosynthetic apparatus were analyzed. Plant development in the mutant lines depended on the light intensity to varying degrees. Lines ch1-1 (lack of the chlorophyllide a oxygenase and rtn16 (decreased chlorophyll a and b amounts were the most susceptible to the light decrease. No one of the investigated lines demonstrated chlorophyll a/b rate alteration under the different light conditions. The depleted chlorophyll content has had the major effect on the mutant plants development under the different light conditions. The different chlorophyll a/b rate correlated with the different adaptability of mutant plants to low light.

  9. Genetic Architecture of Natural Variation in Rice Chlorophyll Content Revealed by a Genome-Wide Association Study.

    Science.gov (United States)

    Wang, Quanxiu; Xie, Weibo; Xing, Hongkun; Yan, Ju; Meng, Xiangzhou; Li, Xinglei; Fu, Xiangkui; Xu, Jiuyue; Lian, Xingming; Yu, Sibin; Xing, Yongzhong; Wang, Gongwei

    2015-06-01

    Chlorophyll content is one of the most important physiological traits as it is closely related to leaf photosynthesis and crop yield potential. So far, few genes have been reported to be involved in natural variation of chlorophyll content in rice (Oryza sativa) and the extent of variations explored is very limited. We conducted a genome-wide association study (GWAS) using a diverse worldwide collection of 529 O. sativa accessions. A total of 46 significant association loci were identified. Three F2 mapping populations with parents selected from the association panel were tested for validation of GWAS signals. We clearly demonstrated that Grain number, plant height, and heading date7 (Ghd7) was a major locus for natural variation of chlorophyll content at the heading stage by combining evidence from near-isogenic lines and transgenic plants. The enhanced expression of Ghd7 decreased the chlorophyll content, mainly through down-regulating the expression of genes involved in the biosynthesis of chlorophyll and chloroplast. In addition, Narrow leaf1 (NAL1) corresponded to one significant association region repeatedly detected over two years. We revealed a high degree of polymorphism in the 5' UTR and four non-synonymous SNPs in the coding region of NAL1, and observed diverse effects of the major haplotypes. The loci or candidate genes identified would help to fine-tune and optimize the antenna size of canopies in rice breeding. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-05-01

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

  11. Effects of tributyltin on the chlorophyll contents of marine microalga Tetraselmis tetrathele, Nannochloropsis oculata and Dunaliella sp

    OpenAIRE

    Rumampuk, Natalie D. C.; Rumengan, Inneke F. M.; Ohji, Madoka; Arai, Takaomi; Miyazaki, Nobuyuki

    2004-01-01

    Three species of marine microalga Tetraselmis tetrathele, Nannochloropsis oculata and Dunaliella sp., the important phyto-plankton in many hatcheries, were used in an acute toxicity test of TBT with emphasis on the chlorophyll a and b contents. After a very short exposure time of three concentrations of TBT, 0.1, 0.5 and 1μgl^, the three species of algae showed different responses. The chlorophyll a and b contents of T. tetrathele in all treatments were higher than those in controls, even be ...

  12. Effect of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings

    International Nuclear Information System (INIS)

    Rupiasih, N. Nyoman; Vidyasagar, Pandit B.

    2016-01-01

    An investigation of the effects of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings has been done. The UV-C irradiation periods of exposure were 30, 60, 90, 120 and 180 minutes. The hypergravity used were 1000 g, 2000 g and 2500 g. The combination treatment is UV-C irradiation for 180 min followed by each hypergravity. The results showed that irradiation of UV-C on wheat seeds have stimulated the seed germination, but hypergravity and combination treatments on wheat seeds have inhibited the seed germination. Those treatments gave negative effects to growth rate, the content of chlorophyll a, b and total chlorophyll of wheat seedlings.

  13. Effect of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Rupiasih, N. Nyoman, E-mail: rupiasih@gmail.com [Department of Physics, Udayana University, Bali (Indonesia); Vidyasagar, Pandit B., E-mail: prof-pbv@yahoo.com [Biophysics Laboratory, Department of Physics, University of Pune, Pune-411007 (India)

    2016-03-11

    An investigation of the effects of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings has been done. The UV-C irradiation periods of exposure were 30, 60, 90, 120 and 180 minutes. The hypergravity used were 1000 g, 2000 g and 2500 g. The combination treatment is UV-C irradiation for 180 min followed by each hypergravity. The results showed that irradiation of UV-C on wheat seeds have stimulated the seed germination, but hypergravity and combination treatments on wheat seeds have inhibited the seed germination. Those treatments gave negative effects to growth rate, the content of chlorophyll a, b and total chlorophyll of wheat seedlings.

  14. Cadmium toxicity affects chlorophyll a and b content, antioxidant enzyme activities and mineral nutrient accumulation in strawberry

    Directory of Open Access Journals (Sweden)

    Ferhad Muradoglu

    2015-01-01

    Full Text Available BACKGROUND: Cadmium (Cd is well known as one of the most toxic metals affecting the environment and can severely restrict plant growth and development. In this study, Cd toxicities were studied in strawberry cv. Camarosa using pot experiment. Chlorophyll and malondialdehyde (MDA contents, catalase (CAT, superoxide dismutase (SOD, ascorbate peroxidase (APX activities and mineral nutrient concentrations were investigated in both roots and leaves of strawberry plant after exposure Cd. RESULTS: Cd content in both roots and leaves was increased with the application of increasing concentrations of Cd. We found higher Cd concentration in roots rather than in leaves. Chlorophyll a and b was decreased in leaves but MDA significantly increased under increased Cd concentration treatments in both roots and leaves. SOD and CAT activities was also increased with the increase Cd concentrations. K, Mn and Mg concentrations were found higher in leaves than roots under Cd stress. In general, increased Cd treatments increased K, Mg, Fe, Ca, Cu and Zn concentration in both roots and leaves. Excessive Cd treatments reduced chlorophyll contents, increased antioxidant enzyme activities and changes in plant nutrition concentrations in both roots and leaves. CONCLUSION: The results presented in this work suggested that Cd treatments have negative effect on chlorophyll content and nearly decreased 30% of plant growth in strawberry. Strawberry roots accumulated higher Cd than leaves. We found that MDA and antioxidant enzyme (CAT, SOD and APX contents may have considered a good indicator in determining Cd tolerance in strawberry plant.

  15. Microscopic observation of symbiotic and aposymbiotic juvenile corals in nutrient-enriched seawater.

    Science.gov (United States)

    Tanaka, Yasuaki; Iguchi, Akira; Inoue, Mayuri; Mori, Chiharu; Sakai, Kazuhiko; Suzuki, Atsushi; Kawahata, Hodaka; Nakamura, Takashi

    2013-03-15

    Symbiotic and aposymbiotic juvenile corals, which were grown in the laboratory from the gametes of the scleractinian coral Acropora digitifera and had settled down onto plastic culture plates, were observed with a microscope under different nutrient conditions. The symbiotic corals successfully removed the surrounding benthic microalgae (BMA), whereas the aposymbiotic corals were in close physical contact with BMA. The areal growth rate of the symbiotic corals was significantly higher than that of the aposymbiotic corals. The addition of nutrients to the culture seawater increased the chlorophyll a content in the symbiotic coral polyps and enhanced the growth of some of the symbiotic corals, however the average growth rate was not significantly affected, most likely because of the competition with BMA. The comparison between the symbiotic and aposymbiotic juvenile corals showed that the establishment of a symbiotic association could be imperative for post-settlement juvenile corals to survive in high-nutrient seawater. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Chlorophyll content in pine (Pinus silvestris L. needles exposed to flue dust from lead and zinc works

    Directory of Open Access Journals (Sweden)

    M. Świeboda

    2015-01-01

    Full Text Available Chlorophyll a and b, sulphur, zinc and lead contents were determined in annual and biennial needles of Scotch pine (Pinus silevstris L. exposed to flue dust-polluted air. Intoxication indexes were calculated on the basis of the obtained results.

  17. Identification and genetic assay of a high-chlorophyll-content mutant in Rice

    International Nuclear Information System (INIS)

    Liu Baofu; Chen Xifeng; Jin Yang; Gu Zhimin; Ma Bojun; Zhu Xudong

    2011-01-01

    A deep rice mutant ZM1120 was screened from the γ-rays irradiation mutation library of Zhonghua 11. Compared to the wild-type control, this mutant were darker (greener) in shoots and leaves, and after sowing 60 and 90 d, the content of chlorophyll were increased by 16.0% and 7.2%, respectively, and the content of carotenoid also increased by 23.1% and 24.2%, respectively. After sowing 90 d the net photosynthetic rate and transpiration rate were increased by 16.3% and 11.4%, respectively. The agronomical traits of this mutant significantly changed, and the traits of plant height, flag-leaf length, flag-leaf width, tiller number per plant, panicle length and setting rate decreased, but the grain length and 1000-grain weight increased by 7.9% and 2.6%. Genetic analysis revealed that the mutation phenotype was controlled by a single recessive nuclear gene, and further cloning and function assay will be useful for understanding the mechanism of photosynthesis and for rice breeding in future. (authors)

  18. Does elevated CO2 ameliorate the impact of O3 on chlorophyll content and photosynthesis in potato (Solanum tuberosum)?

    Science.gov (United States)

    Donnelly, Alison; Craigon, Jim; Black, Colin R.; Colls, Jeremy J.; Landon, Geoff

    2001-04-01

    This study examined the impact of season-long exposure to elevated carbon dioxide (CO2) and ozone (O3), individually and in combination, on leaf chlorophyll content and gas exchange characteristics in potato (Solanum tuberosum L. cv. Bintje). Plants grown in open-top chambers were exposed to three CO2 (ambient, 550 and 680 µmol mol-1) and two O3 treatments (ambient and elevated; 25 and 65 nmol mol-1, 8 h day-1 means, respectively) between crop emergence and maturity; plants were also grown in unchambered field plots. Non-destructive measurements of chlorophyll content and visible foliar injury were made for all treatments at 2-week intervals between 43 and 95 days after emergence. Gas exchange measurements were made for all except the intermediate 550 µmol mol-1 CO2 treatment. Season-long exposure to elevated O3 under ambient CO2 reduced chlorophyll content and induced extensive visible foliar damage, but had little effect on net assimilation rate or stomatal conductance. Elevated CO2 had no significant effect on chlorophyll content, but greatly reduced the damaging impact of O3 on chlorophyll content and visible foliar damage. Light-saturated assimilation rates for leaves grown under elevated CO2 were consistently lower when measured under either elevated or ambient CO2 than in equivalent leaves grown under ambient CO2. Analysis of CO2 response curves revealed that CO2-saturated assimilation rate, maximum rates of carboxylation and electron transport and respiration decreased with time. CO2-saturated assimilation rate was reduced by elevated O3 during the early stages of the season, while respiration was significantly greater under elevated CO2 as the crop approached maturity. The physiological origins of these responses and their implications for the performance of potato in a changing climate are discussed.

  19. Gas exchange, dry weights, and chlorophyll contents of Populus tremuloides seedlings grown from gamma-irradiated seeds

    International Nuclear Information System (INIS)

    Salmonson, B.J.; Zavitkovski, J.

    1977-01-01

    Photosynthesis and respiration rates of Populus tremuloides seedlings grown from seeds acutely irradiated with gamma rays (at levels of 0, 0.47, 0.94, 1.8, 3.7, 7.5, and 15 kr) were measured using a closed system and infrared (IR) gas analyzer. Dry weights of seedling roots and shoots and chlorophyll contents were also determined. In general, gamma irradiation of seed had little effect on subsequent gas-exchange processes in the plant. Net photosynthesis and dark respiration rates of the seedling at any radiation level were not significantly different from those of the control group. Pooled net photosynthesis of all irradiated seedlings was nonsignificantly lower than that of the control seedlings. The data suggested a slight stimulation in dry-matter production of shoots by low levels of gamma radiation. At the highest levels of radiation, shoot dry weight was significantly reduced. Root production displayed a pattern similar to that of shoots. No trends different from controls were evident in the shoot/root ratios. Total chlorophyll concentrations of the seedling increased over the controls by radiation treatment. Age and radiation effects were evident in the chlorophyll a/b ratios. The chlorophyll a/b ratios decreased with age in both the control and treatment groups. Although in seedlings 39 through 46 days old chlorophyll a/b ratios were higher in the control, chlorophyll a/b ratios were significantly higher in the treatment seedlings at 68 days. Changes in chlorophyll a were primarily responsible for this change

  20. Combining machine learning and remotely sensed bandratios to investigate chlorophyll content and photosynthetic processes

    Science.gov (United States)

    Gholizadeh, Hamed

    Photosynthesis in aquatic and terrestrial ecosystems is the key component of the food chain and the most important driver of the global carbon cycle. Therefore, estimation of photosynthesis at large spatial scales is of great scientific importance and can only practically be achieved by remote sensing data and techniques. In this dissertation, remotely sensed information and techniques, as well as field measurements, are used to improve current approaches of assessing photosynthetic processes. More specifically, three topics are the focus here: (1) investigating the application of spectral vegetation indices as proxies for terrestrial chlorophyll in a mangrove ecosystem, (2) evaluating and improving one of the most common empirical ocean-color algorithms (OC4), and (3) developing an improved approach based on sunlit-to-shaded scaled photochemical reflectance index (sPRI) ratios for detecting drought signals in a deciduous forest at eastern United States. The results indicated that although the green normalized difference vegetation index (GNDVI) is an efficient proxy for terrestrial chlorophyll content, there are opportunities to improve the performance of vegetation indices by optimizing the band weights. In regards to the second topic, we concluded that the parameters of the OC4 algorithm and similar empirical models should be tuned regionally and the addition of sea-surface temperature makes the global ocean-color approaches more valid. Results obtained from the third topic showed that considering shaded and sunlit portions of the canopy (i.e., two-leaf models instead of single big leaf models) and taking into account the divergent stomatal behavior of the species (i.e. isohydric and anisohydric) can improve the capability of sPRI in detecting drought. In addition to investigating the photosynthetic processes, the other common theme of the three research topics is the evaluation of "off- the-shelf" solutions to remote-sensing problems. Although widely used

  1. Red Light Represses the Photophysiology of the Scleractinian Coral Stylophora pistillata

    NARCIS (Netherlands)

    Wijgerde, T.H.M.; Melis, A.A.M.; Ferreira Da Silva, C.I.; Leal, M.C.; Vogels, L.; Mutter, C.; Osinga, R.

    2014-01-01

    Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced

  2. Hyperspectral Estimation of the Chlorophyll Content in Short-Term and Long-Term Restorations of Mangrove in Quanzhou Bay Estuary, China

    Directory of Open Access Journals (Sweden)

    Zhiguo Dou

    2018-04-01

    Full Text Available The chlorophyll content can indicate the general health of vegetation, and can be estimated from hyperspectral data. The aim of this study is to estimate the chlorophyll content of mangroves at different stages of restoration in a coastal wetland in Quanzhou, China, using proximal hyperspectral remote sensing techniques. We determine the hyperspectral reflectance of leaves from two mangrove species, Kandelia candel and Aegiceras corniculatum, from short-term and long-term restoration areas with a portable spectroradiometer. We also measure the leaf chlorophyll content (SPAD value. We use partial-least-squares stepwise regression to determine the relationships between the spectral reflectance and the chlorophyll content of the leaves, and establish two models, a full-wave-band spectrum model and a red-edge position regression model, to estimate the chlorophyll content of the mangroves. The coefficients of determination for the red-edge position model and the full-wave-band model exceed 0.72 and 0.82, respectively. The inverted chlorophyll contents are estimated more accurately for the long-term restoration mangroves than for the short-term restoration mangroves. Our results indicate that hyperspectral data can be used to estimate the chlorophyll content of mangroves at different stages of restoration, and could possibly be adapted to estimate biochemical constituents in leaves.

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

    Science.gov (United States)

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

    2009-03-01

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

  4. Plant Family-Specific Impacts of Petroleum Pollution on Biodiversity and Leaf Chlorophyll Content in the Amazon Rainforest of Ecuador.

    Science.gov (United States)

    Arellano, Paul; Tansey, Kevin; Balzter, Heiko; Tellkamp, Markus

    2017-01-01

    In recent decades petroleum pollution in the tropical rainforest has caused significant environmental damage in vast areas of the Amazon region. At present the extent of this damage is not entirely clear. Little is known about the specific impacts of petroleum pollution on tropical vegetation. In a field expedition to the Ecuadorian Amazon over 1100 leaf samples were collected from tropical trees in polluted and unpolluted sites. Plant families were identified for 739 of the leaf samples and compared between sites. Plant biodiversity indices show a reduction of the plant biodiversity when the site was affected by petroleum pollution. In addition, reflectance and transmittance were measured with a field spectroradiometer for every leaf sample and leaf chlorophyll content was estimated using reflectance model inversion with the radiative tranfer model PROSPECT. Four of the 15 plant families that are most representative of the ecoregion (Melastomataceae, Fabaceae, Rubiaceae and Euphorbiaceae) had significantly lower leaf chlorophyll content in the polluted areas compared to the unpolluted areas. This suggests that these families are more sensitive to petroleum pollution. The polluted site is dominated by Melastomataceae and Rubiaceae, suggesting that these plant families are particularly competitive in the presence of pollution. This study provides evidence of a decrease of plant diversity and richness caused by petroleum pollution and of a plant family-specific response of leaf chlorophyll content to petroleum pollution in the Ecuadorian Amazon using information from field spectroscopy and radiative transfer modelling.

  5. The effect of different uranium concentrations on physiological characteristics and chlorophyll contents in sunflowers and soy bean

    International Nuclear Information System (INIS)

    Bagherifam, S.; Lakzian, A.; Ahmadi, S. J.; Fotovat, A.; Rahimi, M. F.

    2009-01-01

    Uranium as a natural radioactive heavy metal, widely disperses throughout the earth's crust. In many cases, the natural abundance has been re-distributed due to anthropogenic activities, resulting in radionuclide contamination in groundwater and surface soil. A pot experiment had been conducted in the Agricultural College Research Greenhouse, at the Ferdowsi University of Mashhad under the controlled condition. The effect of six levels of uranium (0, 50, 100, 250, 500 and 1000 mg U kg -1 ) on physiological characteristics and chlorophyll contents in sunflower and soy bean were studied in a completely randomized design as a factorial experiment with three replications. Plants were harvested after 40 days and before the reproductive stages. Root and stem length, root dry weight, stem dry weight, biomass and chlorophyll contents were determined. The shoot and root length, fresh and dry mass as well as leaf area and chlorophyll contents showed a significant negative correlation with the applied uranium concentrations. The influence on plant growth was also measured in terms of tolerance index and grade of growth inhibition. The results showed that tolerance index increased and grade od growth inhibition decreased with the applied uranium concentration. Biomass and tolerance of sunflower during the experiment on higher uranium concentrations showed that sun flower is more resistant against uranium toxicity

  6. Plant Family-Specific Impacts of Petroleum Pollution on Biodiversity and Leaf Chlorophyll Content in the Amazon Rainforest of Ecuador.

    Directory of Open Access Journals (Sweden)

    Paul Arellano

    Full Text Available In recent decades petroleum pollution in the tropical rainforest has caused significant environmental damage in vast areas of the Amazon region. At present the extent of this damage is not entirely clear. Little is known about the specific impacts of petroleum pollution on tropical vegetation. In a field expedition to the Ecuadorian Amazon over 1100 leaf samples were collected from tropical trees in polluted and unpolluted sites. Plant families were identified for 739 of the leaf samples and compared between sites. Plant biodiversity indices show a reduction of the plant biodiversity when the site was affected by petroleum pollution. In addition, reflectance and transmittance were measured with a field spectroradiometer for every leaf sample and leaf chlorophyll content was estimated using reflectance model inversion with the radiative tranfer model PROSPECT. Four of the 15 plant families that are most representative of the ecoregion (Melastomataceae, Fabaceae, Rubiaceae and Euphorbiaceae had significantly lower leaf chlorophyll content in the polluted areas compared to the unpolluted areas. This suggests that these families are more sensitive to petroleum pollution. The polluted site is dominated by Melastomataceae and Rubiaceae, suggesting that these plant families are particularly competitive in the presence of pollution. This study provides evidence of a decrease of plant diversity and richness caused by petroleum pollution and of a plant family-specific response of leaf chlorophyll content to petroleum pollution in the Ecuadorian Amazon using information from field spectroscopy and radiative transfer modelling.

  7. Red Light Represses the Photophysiology of the Scleractinian Coral Stylophora pistillata

    OpenAIRE

    Wijgerde, Tim; van Melis, Anne; Silva, Catarina I. F.; Leal, Miguel C.; Vogels, Luc; Mutter, Claudia; Osinga, Ronald

    2014-01-01

    Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the individual and combined effects of blue and red light on the health, zooxanthellae density, photophysiology and colouration of the scleractinian coral S...

  8. Using a Chlorophyll Meter to Evaluate the Nitrogen Leaf Content in Flue-Cured Tobacco (Nicotiana tabacum L.

    Directory of Open Access Journals (Sweden)

    Fabio Castelli

    2009-06-01

    Full Text Available In flue-cured tobacco N fertilizer is commonly applied during pre-planting, and very often applied again later as a growth-starter. It is generally held that the efficiency of N-fertilizer use can be improved by evaluating the leaf Nstatus after transplanting and until flowering stage. N use efficiency in this context does not refer merely to the yield but also to the quality, in the meanwhile minimizing the negative effects on the environment. To investigate these aspects, we evaluated the capacity of a Minolta model SPAD-502 chlorophyll meter to estimate the N-status in flue-cured tobacco. The aims was to verify if a relationship exists between SPAD readings and leaf N content, and if a single leaf, in a well defined stalk position, could represent the nitrogen content of the whole plant. During the years 1995 and 1996, a pot experiment was conducted using two flue-cured tobacco varieties. SPAD values, total chlorophyll, total N contents and leaf area were measured throughout the growing season, on each odd leaf stalk position. SPAD values were well-correlated with both total chlorophyll and total N leaf concentration, and the regression coefficients were higher when relationships were calculated on a leaf-area basis. For both relationships, SPAD-total chlorophyll and SPAD-total N, the best fittings were obtained with quadratic equations. One leaf stalk position alone is able to monitor the N-status of the whole plant during the first six weeks after transplanting, without distinction of year and variety effects. The SPAD measurement of one leaf per plant, throughout the vegetative growing season, is therefore a valid tool to test the N-status of the crop in a period when a required N supply is still effective.

  9. Variation in chlorophyll content per unit leaf area in spring wheat and implications for selection in segregating material.

    Directory of Open Access Journals (Sweden)

    John Hamblin

    Full Text Available Reduced levels of leaf chlorophyll content per unit leaf area in crops may be of advantage in the search for higher yields. Possible reasons include better light distribution in the crop canopy and less photochemical damage to leaves absorbing more light energy than required for maximum photosynthesis. Reduced chlorophyll may also reduce the heat load at the top of canopy, reducing water requirements to cool leaves. Chloroplasts are nutrient rich and reducing their number may increase available nutrients for growth and development. To determine whether this hypothesis has any validity in spring wheat requires an understanding of genotypic differences in leaf chlorophyll content per unit area in diverse germplasm. This was measured with a SPAD 502 as SPAD units. The study was conducted in series of environments involving up to 28 genotypes, mainly spring wheat. In general, substantial and repeatable genotypic variation was observed. Consistent SPAD readings were recorded for different sampling positions on leaves, between different leaves on single plant, between different plants of the same genotype, and between different genotypes grown in the same or different environments. Plant nutrition affected SPAD units in nutrient poor environments. Wheat genotypes DBW 10 and Transfer were identified as having consistent and contrasting high and low average SPAD readings of 52 and 32 units, respectively, and a methodology to allow selection in segregating populations has been developed.

  10. Studying of Salinity Stress Effect on Germination, Proline, Sugar, Protein, Lipid and Chlorophyll Content in Purslane (Portulaca oleracea L. Leaves

    Directory of Open Access Journals (Sweden)

    Parvaneh Rahdari

    2012-04-01

    Full Text Available Approximately 30% of country regions are under influence of salt and one of the main important methods for increasing of hectare performance in salt soils, using of resistant plant against with salt such as medicinal annual plant of Purslane (Portulaca oleraceae L..Studying of the salt stress effect on germination and some physiological parameters in Purslane was carried out in completely random framework and with three replications and under controlled conditions. In this study, salinity was imposed by sodium chloride (NaCl and in five levels of framework included of Control (distilled water, 50, 100, 150 and 200 Mmol from NaCl. Studied physiological parameters included of proline, sugar, protein, lipid and chlorophyll in Purslane leaves.In relation with observed germination that increasing of salt level, germination rate was reduced that the least germination rate in 200 Mmol and the highest germination was observed in control which in statistical level 0.01 showed meaningful difference. Also, results showed an increasing of leaf proline and sugar that was synchronize with increasing of sodium chloride, this increasing in statistical level of P<0.01 was meaningful, while blank had the least rate and salt level 200 Mmol was observed. Synchronize with increasing of salinity level, lipid and protein concentration decreasing that was meaningful (P<0.01 which highest of leaf lipid and protein content in control level and least concentration was observed in 200 Mmol of salinity level. Also, salinity stress due to increasing of chlorophyll a and b levels in Purslane leaves which this increasing in leaf chlorophyll b concentrations in 0.01 statistical level was meaningful and the least level chlorophyll a and b in blank and the highest level of chlorophyll a and b by order in 150 and 200 Mmol of NaCl was observed. The results showed that plant for resistance against salinity increasing of proline, sugar and chlorophyll content in leaves are useful for

  11. The effects of different salt concentrations on growth and chlorophyll content of some pumpkin rootstocks

    Directory of Open Access Journals (Sweden)

    Köksal AYDİNŞAKİR

    2015-12-01

    Full Text Available This study was conducted to determine the effects of different salinity levels, (0.7, 4.0, 8.0, 12.0, 16.0 dS m-1 on some physiological parameters of Obez F1, Ferro F1, RS841 F1, which are used as rootstocks in watermelon cultivation. Salty irrigation water was obtained through mixing of NaCl and CaCl2 salt into tap water. When the plants were at the 3-4 leaf stage, different salinity levels were applied. Plants were harvested during the phase of florescence. The study was carried out using split plots in randomized complete block design while rootstocks are main plot, salinity levels are sub-plot with three replications. While the salinity level was increasing, the physiological parameters decreased in each three rootstocks. While the plant height changed between 14.4-107.1 cm, the plant leaf area varied between 152.0-2182.7 cm2. Chlorophyll-a, chlorophyll-b and total carotenoid values decreased as the salinity level increased. Excluding the maximum value obtained from control plot, the highest chlorophyll-a, chlorophyll-b, and total carotenoid values were obtained in Obez variety under 4.0 dS m-1 application with 14.8 mg l-1, 12.8 mg l-1 and 0.28 mg g-1 fw, respectively.

  12. Changes of Chlorophyll Index (SPAD, Relative Water Content, Electrolyte Leakage and Seed Yield in Spring Safflower Genotypes under Irrigation Termination

    Directory of Open Access Journals (Sweden)

    B.E. Moosavifar

    2012-04-01

    Full Text Available In order to evaluate the effect of irrigation termination and genotype on chlorophyll index (SPAD, relative water content, electrolyte leakage and seed yield in spring safflower, an experiment was conducted, in a spilt plot arrangement based on randomized complete block design with four replications at Research Farm, Faculty of Agriculture, the University of Birjand, during 2008. Irrigation regimes (full irrigation (whole season irrigation, irrigation until grain filling, flowering and heading-bud and genotypes (Mahali Isfahan (a local variety, Isfahan28 and IL111 were arranged in main and subplots, respectively. Results showed chlorophyll content, relative water content, cell membrane stability and seed yield were influenced by irrigation termination. Provided that with terminating irrigation at an earlier stage, an increase in electrolyte leakage and reduction in relative water content and seed yield was observed in plants. There were negative relations between electrolyte leakage from plants leaf cells and seed yield. Plants which experienced irrigation termination in an earlier growth stage, suffered more damage to their cell membranes, leading to depression of their production potential. Based on the results, Mahali Isfahan and Isfahan28 can be introduced as drought resistant genotypes, because of their lower electrolyte leakage and higher relative water content. But, in general, Mahali Isfahan had the highest seed yield due to its nativeness and high adaptation to arid conditions southern of Khorasan, and therefore this genotype suggests for planting in the region.

  13. Effect Of Heavy Metals Stress On Enzyme Activities And Chlorophyll Content Of Pea (Pisum Sativum) And Tomato Plants

    International Nuclear Information System (INIS)

    Ahmed, B.M.; El Maghrabi, G.; Hashem, M.F.

    2013-01-01

    The effects of heavy metal stress on the chlorophyll in addition to catalase and peroxidase activities were studied in the leaves and roots of tomato and pea plants. Four groups were studied; the control group and other three groups treated with heavy metals. Group 1HM was treated with 1.0 mg CuSO 4 /l + 0.2 mg CdSO 4 /l + 0.1 mg ZnNO 3 /l every 10 days while in group 5 HM and group 10 HM, the doses were 5 and 10 folds the 1 HM, respectively. Leaves and roots of control and heavy metal-stressed plants were harvested after 10 weeks for chlorophyll determination. The chlorophyll content, especially chlo. b, was significantly decreased with the increase in heavy metals stress in both plants. In leaves of heavy metal-stressed plants, the peroxidase level in different stress levels was increased with increasing stress levels in tomato and pea while catalase was unchanged in leaves of tomato in comparison with the control. The activities of catalase and peroxidase in roots of heavy metal-stressed plants were increased in group 5 HM then decreased in case of group 10 HM. The increase in enzyme activities demonstrated that tomato is more tolerant to heavy metals than pea

  14. Retrieval of spruce leaf chlorophyll content from airborne image data using continuum removal and radiative transfer

    Czech Academy of Sciences Publication Activity Database

    Malenovský, Z.; Homolová, L.; Zurita-Milla, R.; Lukeš, Petr; Kaplan, Věroslav; Hanuš, Jan; Gastellu-Etchegory, J.P.; Schaepman, M.E.

    2013-01-01

    Roč. 131, APR (2013), s. 85-102 ISSN 0034-4257 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:67179843 Keywords : Chlorophyll retrieval * Imaging spectroscopy * Continuum removal * Radiative transfer * PROSPECT * DART * Optical indices * Norway spruce * High spatial resolution * AISA Subject RIV: EH - Ecology, Behaviour Impact factor: 4.769, year: 2013

  15. Estimation of Spruce Needle-Leaf Chlorophyll Content Based on DART and PARAS Canopy Reflectance Models

    Czech Academy of Sciences Publication Activity Database

    Yáñez-Rausell, L.; Malenovský, Z.; Rautiainen, M.; Clevers, J G P W.; Lukeš, Petr; Hanuš, Jan; Schaepman, M. E.

    2015-01-01

    Roč. 8, č. 4 (2015), s. 1534-1544 ISSN 1939-1404 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Chlorophyll a plus b estimation * CHRIS-PROBA * coniferous forest * continuum removal * discrete anisotropic radiative transfer model (DART) * needle-leaf * Norway spruce * optical indices * PARAS * PROSPECT * radiative transfer * recollision probability Subject RIV: EH - Ecology, Behaviour Impact factor: 2.145, year: 2015

  16. Lipid content and composition of oocytes from five coral species: potential implications for future cryopreservation efforts.

    Directory of Open Access Journals (Sweden)

    Chiahsin Lin

    Full Text Available Given the previously documented importance of lipid concentration and composition in the successful cryopreservation of gorgonian corals, these parameters were assessed in oocytes of five species of scleractinian coral; Platygyra daedalea, Echinopora gemmacea, Echinophyllia aspera, Oxypora lacera and Astreopora expansa. Wax esters, phosphatidylethanolamine, phosphatidylcholine, and fatty acids were all measured at detectable levels, and the latter were produced at significantly elevated quantities in E. gemmacea, E. aspera, and O. lacera. On the other hand, phosphatidylethanolamine, phosphatidylcholine, and wax ester were found at significantly higher concentrations in A. expansa oocytes. Triacylglycerol was not present in any species. Interestingly, the total lipid content of oocytes from all five scleractinians was significantly lower than that of oocytes of two gorgonian species, Junceella juncea and Junceella fragilis. As higher total lipid concentrations may be correlated with greater degrees of cellular membrane fluidity at lower temperatures, it stands to reason that gorgonian coral oocytes may be more likely to survive the cryopreservation process than oocytes of scleractinian corals.

  17. Effects of Wood Ash Biomass Application on Growth Indices and Chlorophyll Content of Maize and Lima bean Intercrop

    Directory of Open Access Journals (Sweden)

    Rasheedat Ajala

    2017-07-01

    Full Text Available Wood ash generated from wood industries have enormous potential which can be utilized due to its properties which influences soil chemistry and fertility status of tropical acidic soils. Field experiments were conducted on an acidic sandy loam alfisol to investigate the effects of wood ash on the growth indices and chlorophyll content of maize and lima beans intercrop during the late and early seasons of 2014 and 2015 at Akure in the rainforest zone of southwestern Nigeria. The treatments were 100% sole maize with ash, 100% sole maize without ash, 75% maize + 25% lima beans with ash, 75% + 25% lima beans without ash, 50% maize + 50% lima beans with ash, 50% maize + 50% lima beans without ash, 25% maize + 75% lima beans with ash and 25% maize + 75% lima beans without ash. Wood ash was applied at 2.4kg/plot. Wood ash increased chlorophyll content in all amended treatments except in amended 25:75% maize-lima beans intercrop and 25:75% maize –lima beans intercrop without ash, however 75:25% maize-lima beans amended with wood ash significantly (P≥0.05 recorded the highest chlorophyll content. Growth parameters such as plant height, number of leaves, leaf area, leaf area index, leaf length, stem diameter, number of flowers, number of pods, weight of plant and total biomass of amended maize-lima beans intercrop were significantly (P≥0.05 increased by wood ash application. Based on experimental findings, 25:75% maize-lima beans intercrop and 75%:25% maize-lima beans intercrop amended with wood ash was concluded to be more recommendable in the study area.

  18. Effect of Elevated Atmospheric CO2 and Temperature on Leaf Optical Properties and Chlorophyll Content in Acer saccharum (Marsh.)

    Science.gov (United States)

    Carter, Gregory A.; Bahadur, Raj; Norby, Richard J.

    1999-01-01

    Elevated atmospheric CO2 pressure and numerous causes of plant stress often result in decreased leaf chlorophyll contents and thus would be expected to alter leaf optical properties. Hypotheses that elevated carbon dioxide pressure and air temperature would alter leaf optical properties were tested for sugar maple (Acer saccharum Marsh.) in the middle of its fourth growing season under treatment. The saplings had been growing since 1994 in open-top chambers at Oak Ridge, Tennessee under the following treatments: 1) Ambient CO2 pressure and air temperature (control); 2) CO2 pressure approximately 30 Pa above ambient; 3) Air temperatures 3 C above ambient; 4) Elevated CO2 and air temperature. Spectral reflectance, transmittance, and absorptance in the visible spectrum (400-720 nm) did not change significantly (rho = 0.05) in response to any treatment compared with control values. Although reflectance, transmittance, and absorptance at 700 nm correlated strongly with leaf chlorophyll content, chlorophyll content was not altered significantly by the treatments. The lack of treatment effects on pigmentation explained the non-significant change in optical properties in the visible spectrum. Optical properties in the near-infrared (721-850 nm) were similarly unresponsive to treatment with the exception of an increased absorptance in leaves that developed under elevated air temperature alone. This response could not be explained by the data, but might have resulted from effects of air temperature on leaf internal structure. Results indicated no significant potential for detecting leaf optical responses to elevated CO2 or temperature by the remote sensing of reflected radiation in the 400-850 nm spectrum.

  19. Influence of root-knot nematode infestation on antioxidant enzymes, chlorophyll content and growth in Pogostemon cablin (Blanco) Benth.

    Science.gov (United States)

    Bhau, B S; Borah, Bitupon; Ahmed, Reshma; Phukon, P; Gogoi, Barbi; Sarmah, D K; Lal, M; Wann, S B

    2016-04-01

    Plants adapt themselves to overcome adverse environmental conditions, and this involves a plethora of concurrent cellular activities. Physiological experiments or metabolic profiling can quantify this response. Among several diseases of Pogostemon cablin (Blanco) Benth. (Patchouli), root-knot nematode infection caused by Meloidogyne incognita (Kofoid and White) Chitwood causes severe damage to the plant and hence, the oil production. In the present study, we identified M. incognita morphologically and at molecular level using sequenced characterized amplified region marker (SCAR). M. incognita was artificially inoculated at different levels of second stage juveniles (J₂) to examine the effect on Patchouli plant growth parameters. Peroxidase and polyphenol oxidase enzyme activity and changes in the total phenol and chlorophyll contents in M. incognita was also evaluated in response to infection. The results have demonstrated that nematode infestation leads to increased peroxidase activities in the leaves of the patchouli plants and thereby, increase in phenolic content as a means of defence against nematode infestation. Chlorophyll content was also found decreased but no changes in polyphenol oxidase enzyme activity.

  20. Analysis of chlorophyll content and its correlation with yield attributing traits on early varieties of maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Bikal Ghimire

    2015-12-01

    Full Text Available Chlorophyll has direct roles on photosynthesis and hence closely relates to capacity for photosynthesis, development and yield of crops. With object to explore the roles of chlorophyll content and its relation with other yield attributing traits a field research was conducted using fourteen early genotypes of maize in RCBD design with three replications. Observations were made for Soil Plant Analysis Development (SPAD reading, ear weight, number of kernel row/ear, number of kernel/row, five hundred kernel weight and grain yield/hectare and these traits were analyzed using Analysis of Variance (ANOVA and correlation coefficient analysis. SPAD reading showed a non-significant variation among the genotypes while it revealed significant correlation with no. of kernel/row, grain yield/hectare and highly significant correlation with no. of kernel row/ear and ear weight which are the most yield determinative traits. For the trait grain yield/ha followed by number of kernel row/ear genotype ARUN-1EV has been found comparatively superior to ARUN-2 (standard check. Grain Yield/hectare was highly heritable (>0.6 while no. of kernel / row, SPAD reading, ear weight, number of kernel row/ear were moderately heritable (0.3-0.6. Correlation analysis and ANOVA revealed ARUN-1EV, comparatively superior to ARUN-2 (standard check, had higher SPAD reading than mean SPAD reading with significant correlation with no. of kernel/row, no. of kernel row/ear, ear weight and grain yield/ha which are all yield determinative traits . This showed positive and significant effect of chlorophyll content in grain yield of the maize.

  1. The global distribution of leaf chlorophyll content and seasonal controls on carbon uptake

    Science.gov (United States)

    Croft, H.; Chen, J. M.; Luo, X.; Bartlett, P. A.; Staebler, R. M.; He, L.; Mo, G.; Luo, S.; Simic, A.; Arabian, J.; He, Y.; Zhang, Y.; Beringer, J.; Hutley, L. B.; Noland, T. L.; Arellano, P.; Stahl, C.; Homolová, L.; Bonal, D.; Malenovský, Z.; Yi, Q.; Amiri, R.

    2017-12-01

    Leaf chlorophyll (ChlLeaf) is crucial to biosphere-atmosphere exchanges of carbon and water, and the functioning of terrestrial ecosystems. Improving the accuracy of modelled photosynthetic carbon uptake is a central priority for understanding ecosystem response to a changing climate. A source of uncertainty within gross primary productivity (GPP) estimates is the failure to explicitly consider seasonal controls on leaf photosynthetic potential. Whilst the inclusion of ChlLeafinto carbon models has shown potential to provide a physiological constraint, progress has been hampered by the absence of a spatially-gridded, global chlorophyll product. Here, we present the first spatially-continuous, global view of terrestrial ChlLeaf, at weekly intervals. Satellite-derived ChlLeaf was modelled using a physically-based radiative transfer modelling approach, with a two stage model inversion method. 4-Scale and SAIL canopy models were first used to model leaf-level reflectance from ENIVSAT MERIS 300m satellite data. The PROSPECT leaf model was then used to derive ChlLeaf from the modelled leaf reflectance. This algorithm was validated using measured ChlLeaf data from 248 measurements within 26 field locations, covering six plant functional types (PFTs). Modelled results show very good relationships with measured data, particularly for deciduous broadleaf forests (R2 = 0.67; pmake an important step towards improving the accuracy of global carbon budgets.

  2. Adaptive changes in chlorophyll content and photosynthetic features to low light in Physocarpus amurensis Maxim and Physocarpus opulifolius "Diabolo".

    Science.gov (United States)

    Zhang, Huihui; Zhong, Haixiu; Wang, Jifeng; Sui, Xin; Xu, Nan

    2016-01-01

    The present study aims to investigate the differences in leaf pigment content and the photosynthetic characteristics under natural and low light intensities between the Chinese native Physocarpus amurensis Maxim and the imported Physocarpus opulifolius "Diabolo" from North America. We aim to discuss the responses and the adaptive mechanism of these two cultivars of Physocarpus to a low light environment. The results show that the specific leaf area (SLA) and the chlorophyll content were significantly increased in the leaves of both Physocarpus cultivars in response to a low light intensity, and the SLA and chlorophyll content were higher in the leaves of low light-treated P. opulifolius "Diabolo" compared with the leaves of low light-treated P. amurensis Maxim. Moreover, the content of anthocyanin was markedly reduced in the leaves of P. opulifolius "Diabolo" under low light intensity, which allowed for a greater capacity of photon capture under the low light condition. Under natural light, the photosynthetic carbon assimilation capacity was greater in the leaves of P. amurensis Maxim compared with the leaves of P. opulifolius "Diabolo" that were rich with anthocyanin. However, in response to low light, AQY, P max, LCP and LSP decreased to a lesser extent in the leaves of P. opulifolius "Diabolo" compared with the leaves of P. amurensis Maxim. These results suggest that P. opulifolius "Diabolo" exhibits a greater ability in adaption to low light, and it is probably related to the relatively higher chlorophyll content and the smaller SLA in the leaves of P. opulifolius "Diabolo." In addition, the low light intensity resulted in a reduced photochemical activity of photosystem (PS) II in the leaves of both Physocarpus, as evidenced by increased values of the relative variable fluorescence at point J and point I on the OJIP curve. This result suggests that the electron acceptor in PS II was the major responsive site to the low light stress in the leaves of both

  3. Off-Nadir Hyperspectral Sensing for Estimation of Vertical Profile of Leaf Chlorophyll Content within Wheat Canopies.

    Science.gov (United States)

    Kong, Weiping; Huang, Wenjiang; Casa, Raffaele; Zhou, Xianfeng; Ye, Huichun; Dong, Yingying

    2017-11-23

    Monitoring the vertical profile of leaf chlorophyll (Chl) content within winter wheat canopies is of significant importance for revealing the real nutritional status of the crop. Information on the vertical profile of Chl content is not accessible to nadir-viewing remote or proximal sensing. Off-nadir or multi-angle sensing would provide effective means to detect leaf Chl content in different vertical layers. However, adequate information on the selection of sensitive spectral bands and spectral index formulas for vertical leaf Chl content estimation is not yet available. In this study, all possible two-band and three-band combinations over spectral bands in normalized difference vegetation index (NDVI)-, simple ratio (SR)- and chlorophyll index (CI)-like types of indices at different viewing angles were calculated and assessed for their capability of estimating leaf Chl for three vertical layers of wheat canopies. The vertical profiles of Chl showed top-down declining trends and the patterns of band combinations sensitive to leaf Chl content varied among different vertical layers. Results indicated that the combinations of green band (520 nm) with NIR bands were efficient in estimating upper leaf Chl content, whereas the red edge (695 nm) paired with NIR bands were dominant in quantifying leaf Chl in the lower layers. Correlations between published spectral indices and all NDVI-, SR- and CI-like types of indices and vertical distribution of Chl content showed that reflectance measured from 50°, 30° and 20° backscattering viewing angles were the most promising to obtain information on leaf Chl in the upper-, middle-, and bottom-layer, respectively. Three types of optimized spectral indices improved the accuracy for vertical leaf Chl content estimation. The optimized three-band CI-like index performed the best in the estimation of vertical distribution of leaf Chl content, with R² of 0.84-0.69, and RMSE of 5.37-5.56 µg/cm² from the top to the bottom layers

  4. Metabolomics reveals biotic and abiotic elicitor effects on the soft coral Sarcophyton ehrenbergi terpenoid content.

    Science.gov (United States)

    Farag, Mohamed A; Al-Mahdy, Dalia A; Meyer, Achim; Westphal, Hildegard; Wessjohann, Ludger A

    2017-04-05

    The effects of six biotic and abiotic elicitors, i.e. MeJA (methyl jasmonate), SA (salicylic acid), ZnCl 2 , glutathione and β-glucan BG (fungal elicitor), and wounding, on the secondary metabolite accumulation in the soft coral Sarcophyton ehrenbergi were assessed. Upon elicitation, metabolites were extracted and analysed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Except for MeJA, no differences in photosynthetic efficiency were observed after treatments, suggesting the absence of a remarkable stress on primary production. Chemometric analyses of UPLC-MS data showed clear segregation of SA and ZnCl 2 elicited samples at 24 and 48 h post elicitation. Levels of acetylated diterpene and sterol viz., sarcophytonolide I and cholesteryl acetate, was increased in ZnCl 2 and SA groups, respectively, suggesting an activation of specific acetyl transferases. Post elicitation, sarcophytonolide I level increased 132 and 17-folds at 48 h in 0.1 mM SA and 1 mM ZnCl 2 groups, respectively. Interestingly, decrease in sarcophine, a major diterpene was observed only in response to ZnCl 2 , whereas no change was observed in sesquiterpene content following treatments. To the best of our knowledge, this study provides the first documentation for elicitation effects on a soft corals secondary metabolome and suggests that SA could be applied to increase diterpenoid levels in corals.

  5. Agrobacterium rhizogenes rolB gene affects photosynthesis and chlorophyll content in transgenic tomato (Solanum lycopersicum L.) plants.

    Science.gov (United States)

    Bettini, Priscilla P; Marvasi, Massimiliano; Fani, Fabiola; Lazzara, Luigi; Cosi, Elena; Melani, Lorenzo; Mauro, Maria Luisa

    2016-10-01

    Insertion of Agrobacterium rhizogenes rolB gene into plant genome affects plant development, hormone balance and defence. However, beside the current research, the overall transcriptional response and gene expression of rolB as a modulator in plant is unknown. Transformed rolB tomato plant (Solanum lycopersicum L.) cultivar Tondino has been used to investigate the differential expression profile. Tomato is a well-known model organism both at the genetic and molecular level, and one of the most important commercial food crops in the world. Through the construction and characterization of a cDNA subtracted library, we have investigated the differential gene expression between transgenic clones of rolB and control tomato and have evaluated genes specifically transcribed in transgenic rolB plants. Among the selected genes, five genes encoding for chlorophyll a/b binding protein, carbonic anhydrase, cytochrome b 6 /f complex Fe-S subunit, potassium efflux antiporter 3, and chloroplast small heat-shock protein, all involved in chloroplast function, were identified. Measurement of photosynthesis efficiency by the level of three different photosynthetic parameters (F v /F m , rETR, NPQ) showed rolB significant increase in non-photochemical quenching and a, b chlorophyll content. Our results point to highlight the role of rolB on plant fitness by improving photosynthesis. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Estimating the chlorophyll content in the waters of Guanabara Bay from the LANDSAT multispectral scanning digital data

    Science.gov (United States)

    Dejesusparada, N. (Principal Investigator); Bentancurt, J. J. V.; Herz, B. R.; Molion, L. B.

    1980-01-01

    Detection of water quality in Guanabara Bay using multispectral scanning digital data taken from LANDSAT satellites was examined. To test these processes, an empirical (statistical) approach was choosen to observe the degree of relationship between LANDSAT data and the in situ data taken simultaneously. The linear and nonlinear regression analyses were taken from among those developed by INPE in 1978. Results indicate that the major regression was in the number six MSS band, atmospheric effects, which indicated a correction coefficient of 0.99 and an average error of 6.59 micrograms liter. This error was similar to that obtained in the laboratory. The chlorophyll content was between 0 and 100 micrograms/liter, as taken from the MSS of LANDSAT.

  7. Seasonal and inter-annual variation in the chlorophyll content of three co-existing Sphagnum species exceeds the effect of solar UV reduction in a subarctic peatland.

    Science.gov (United States)

    Hyyryläinen, Anna; Rautio, Pasi; Turunen, Minna; Huttunen, Satu

    2015-01-01

    We measured chlorophyll (chl) concentration and chl a/b ratio in Sphagnum balticum, S. jensenii, and S. lindbergii, sampled after 7 and 8 years of ultraviolet-B (UVB) and temperature manipulation in an open field experiment in Finnish Lapland (68°N). We used plastic filters with different transmittance of UVB radiation to manipulate the environmental conditions. The plants were exposed to (1) attenuated UVB and increased temperature, (2) ambient UVB and increased temperature and (3) ambient conditions. Chlorophyll was extracted from the capitula of the mosses and the content and a/b ratio were measured spectrophotometrically. Seasonal variation of chlorophyll concentration in the mosses was species specific. Temperature increase to 0.5-1 °C and/or attenuation of solar UVB radiation to ca. one fifth of the ambient (on average 12 vs. 59 uW/cm(2)) had little effect on the chlorophyll concentration or its seasonal variation. In the dominant S. lindbergii, UVB attenuation under increased temperature led to a transient decrease in chlorophyll concentration. Altogether, species-specific patterns of seasonal chlorophyll variation in the studied Sphagna were more pronounced than temperature and UVB treatment effects.

  8. Beneficial role of spermidine in chlorophyll metabolism and D1 protein content in tomato seedlings under salinity-alkalinity stress.

    Science.gov (United States)

    Hu, Lipan; Xiang, Lixia; Li, Shuting; Zou, Zhirong; Hu, Xiao-Hui

    2016-04-01

    Polyamines are important in protecting plants against various environmental stresses, including protection against photodamage to the photosynthetic apparatus. The molecular mechanism of this latter effect is not completely understood. Here, we have investigated the effects of salinity-alkalinity stress and spermidine (Spd) on tomato seedlings at both physiological and transcriptional levels. Salinity-alkalinity stress decreased leaf area, net photosynthetic rate, maximum net photosynthetic rate, light saturation point, apparent quantum efficiency, total chlorophyll, chlorophyll a and chlorophyll a:chlorophyll b relative to the control. The amount of D1 protein, an important component of photosystem II, was reduced compared with the control, as was the expression of psbA, which codes for D1. Expression of the chlorophyll biosynthesis gene porphobilinogen deaminase (PBGD) was reduced following salinity-alkalinity stress, whereas the expression of Chlase, which codes for chlorophyllase, was increased. These negative physiological effects of salinity-alkalinity stress were alleviated by exogenous Spd. Expression of PBGD and psbA were enhanced, whereas the expression of Chlase was reduced, when exogenous Spd was included in the stress treatment compared with when it was not. The protective effect of Spd on chlorophyll and D1 protein content during stress may maintain the photosynthetic apparatus, permitting continued photosynthesis and growth of tomato seedlings (Solanum lycopersicum cv. Jinpengchaoguan) under salinity-alkalinity stress. © 2015 Scandinavian Plant Physiology Society.

  9. Laser light and magnetic field stimulation effect on biochemical, enzymes activities and chlorophyll contents in soybean seeds and seedlings during early growth stages.

    Science.gov (United States)

    Asghar, Tehseen; Jamil, Yasir; Iqbal, Munawar; Zia-Ul-Haq; Abbas, Mazhar

    2016-12-01

    Laser and magnetic field bio-stimulation attracted the keen interest of scientific community in view of their potential to enhance seed germination, seedling growth, physiological, biochemical and yield attributes of plants, cereal crops and vegetables. Present study was conducted to appraise the laser and magnetic field pre-sowing seed treatment effects on soybean sugar, protein, nitrogen, hydrogen peroxide (H 2 O 2 ) ascorbic acid (AsA), proline, phenolic and malondialdehyde (MDA) along with chlorophyll contents (Chl "a" "b" and total chlorophyll contents). Specific activities of enzymes such as protease (PRT), amylase (AMY), catalyst (CAT), superoxide dismutase (SOD) and peroxides (POD) were also assayed. The specific activity of enzymes (during germination and early growth), biochemical and chlorophyll contents were enhanced significantly under the effect of both laser and magnetic pre-sowing treatments. Magnetic field treatment effect was slightly higher than laser treatment except PRT, AMY and ascorbic acid contents. However, both treatments (laser and magnetic field) effects were significantly higher versus control (un-treated seeds). Results revealed that laser and magnetic field pre-sowing seed treatments have potential to enhance soybean biological moieties, chlorophyll contents and metabolically important enzymes (degrade stored food and scavenge reactive oxygen species). Future study should be focused on growth characteristics at later stages and yield attributes. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Enhancement of carotenoid and chlorophyll content of an edible freshwater alga (Kai: Cladophora sp. by supplementary inorganic phosphate and investigation of its biomass production

    Directory of Open Access Journals (Sweden)

    Siripen Traichaiyaporn

    2012-01-01

    Full Text Available Enhancement of the carotenoid and chlorophyll content of an edible freshwater alga (Kai:Cladophora sp. by supplementary inorganic phosphate in canteen wastewater was investigated. Themass cultivation of the alga was conducted at ambient temperature and light intensity in dilutedcanteen wastewater enhanced with dipotassium hydrogen phosphate at 5-20 mg L-1. An increase intotal carotenoid and chlorophyll was observed. However, it had no effect on biomass production. Asa result of the algal cultivation, there was a dramatic improvement in the quality of canteen wastewater.

  11. Copy Number Variation of Cytokinin Oxidase Gene Tackx4 Associated with Grain Weight and Chlorophyll Content of Flag Leaf in Common Wheat.

    Science.gov (United States)

    Chang, Cheng; Lu, Jie; Zhang, Hai-Ping; Ma, Chuan-Xi; Sun, Genlou

    2015-01-01

    As the main pigment in photosynthesis, chlorophyll significantly affects grain filling and grain weight of crop. Cytokinin (CTK) can effectively increase chlorophyll content and chloroplast stability, but it is irreversibly inactivated by cytokinin oxidase (CKX). In this study, therefore, twenty-four pairs of primers were designed to identify variations of wheat CKX (Tackx) genes associated with flag leaf chlorophyll content after anthesis, as well as grain weight in 169 recombinant inbred lines (RIL) derived from Triticum aestivum Jing 411 × Hongmangchun 21. Results indicated variation of Tackx4, identified by primer pair T19-20, was proven to significantly associate with chlorophyll content and grain weight in the RIL population. Here, two Tackx4 patterns were identified: one with two co-segregated fragments (Tackx4-1/Tackx4-2) containing 618 bp and 620 bp in size (as in Jing 411), and another with no PCR product. The two genotypes were designated as genotype-A and genotype-B, respectively. Grain weight and leaf chlorophyll content at 5~15 days after anthesis (DAA) were significantly higher in genotype-A lines than those in genotype-B lines. Mapping analysis indicated Tackx4 was closely linked to Xwmc169 on chromosome 3AL, as well as co-segregated with a major quantitative trait locus (QTL) for both grain weight and chlorophyll content of flag leaf at 5~15 DAA. This QTL explained 8.9~22.3% phenotypic variations of the two traits across four cropping seasons. Among 102 wheat varieties, a third genotype of Tackx4 was found and designated as genotype-C, also having two co-segregated fragments, Tackx4-2 and Tackx4-3 (615bp). The sequences of three fragments, Tackx4-1, Tackx4-2, and Tackx4-3, showed high identity (>98%). Therefore, these fragments could be considered as different copies at Tackx4 locus on chromosome 3AL. The effect of copy number variation (CNV) of Tackx4 was further validated. In general, genotype-A contains both significantly higher grain weight

  12. Growth and content of Spirulina platensis biomass chlorophyll cultivated at different values of light intensity and temperature using different nitrogen sources

    Directory of Open Access Journals (Sweden)

    Eliane Dalva Godoy Danesi

    2011-03-01

    Full Text Available The effects of light intensity and temperature in S. platensis cultivation with potassium nitrate or urea as nitrogen source were investigated, as well as the biomass chlorophyll contents of this cyanobacteria, through the Response Surface Methodology. Experiments were performed at temperatures from 25 to 34.5ºC and light intensities from 15 to 69 µmol photons m-2 s-1, in mineral medium. In cultivations with both sources of nitrogen, KNO3 and urea, statistic evaluation through multiple regression, no interactions of such independent variables were detected in the results of the dependent variables maximum cell concentration, chlorophyll biomass contents, cell and chlorophyll productivities, as well as in the nitrogen-cell conversion factor. In cultivation performed with both sources of nitrogen, it was possible to obtain satisfactory adjustments to relate the dependent variables to the independent variables. The best results were achieved at temperature of 30ºC, at light intensity of 60 µmol photons m-2s-1, for cell growth, with cell productivity of approximately 95 mg L-1 d-1 in cultivations with urea. For the chlorophyll biomass content, the most adequate light intensity was 24 µmol photons m-2 s-1.

  13. Development of FT-NIR Models for the Simultaneous Estimation of Chlorophyll and Nitrogen Content in Fresh Apple (Malus Domestica Leaves

    Directory of Open Access Journals (Sweden)

    Elena Tamburini

    2015-01-01

    Full Text Available Agricultural practices determine the level of food production and, to great extent, the state of the global environment. During the last decades, the indiscriminate recourse to fertilizers as well as the nitrogen losses from land application have been recognized as serious issues of modern agriculture, globally contributing to nitrate pollution. The development of a reliable Near-Infra-Red Spectroscopy (NIRS-based method, for the simultaneous monitoring of nitrogen and chlorophyll in fresh apple (Malus domestica leaves, was investigated on a set of 133 samples, with the aim of estimating the nutritional and physiological status of trees, in real time, cheaply and non-destructively. By means of a FT (Fourier Transform-NIR instrument, Partial Least Squares (PLS regression models were developed, spanning a concentration range of 0.577%–0.817% for the total Kjeldahl nitrogen (TKN content (R2 = 0.983; SEC = 0.012; SEP = 0.028, and of 1.534–2.372 mg/g for the total chlorophyll content (R2 = 0.941; SEC = 0.132; SEP = 0.162. Chlorophyll-a and chlorophyll-b contents were also evaluated (R2 = 0.913; SEC = 0.076; SEP = 0.101 and R2 = 0.899; SEC = 0.059; SEP = 0.101, respectively. All calibration models were validated by means of 47 independent samples. The NIR approach allows a rapid evaluation of the nitrogen and chlorophyll contents, and may represent a useful tool for determining nutritional and physiological status of plants, in order to allow a correction of nutrition programs during the season.

  14. Integrating multiple vegetation indices via an artificial neural network model for estimating the leaf chlorophyll content of Spartina alterniflora under interspecies competition.

    Science.gov (United States)

    Liu, Pudong; Shi, Runhe; Zhang, Chao; Zeng, Yuyan; Wang, Jiapeng; Tao, Zhu; Gao, Wei

    2017-10-31

    The invasive species Spartina alterniflora and native species Phragmites australis display a significant co-occurrence zonation pattern and this co-exist region exerts most competitive situations between these two species, competing for the limited space, directly influencing the co-exist distribution in the future. However, these two species have different growth ratios in this area, which increase the difficulty to detect the distribution situation directly by remote sensing. As chlorophyll content is a key indicator of plant growth and physiological status, the objective of this study was to reduce the effect of interspecies competition when estimating Cab content; we evaluated 79 published representative indices to determine the optimal indices for estimating the chlorophyll a and b (Cab) content. After performing a sensitivity analysis for all 79 spectral indices, five spectral indices were selected and integrated using an artificial neural network (ANN) to estimate the Cab content of different competition ratios: the Gitelson ratio green index, the transformed chlorophyll absorption ratio index/optimized soil-adjusted vegetation index, the modified normalized difference vegetation index, the chlorophyll fluorescence index, and the Vogelmann chlorophyll index. The ANN method yielded better results (R 2  = 0.7110 and RMSE = 8.3829 μg cm -2 ) on average than the best single spectral index (R 2  = 0.6319 and RMSE = 9.3535 μg cm -2 ), representing an increase of 10.78% in R 2 and a decrease of 10.38% in RMSE. Our results indicated that integrating multiple vegetation indices with an ANN can alleviate the impact of interspecies competition and achieve higher estimation accuracy than the traditional approach using a single index.

  15. Does Primary Productivity Turn Up the Volume? Exploring the Relationship Between Chlorophyll a and the Soundscape of Coral Reefs in the Pacific.

    Science.gov (United States)

    Fisher-Pool, Pollyanna I; Lammers, Marc O; Gove, Jamison; Wong, Kevin B

    2016-01-01

    Chlorophyll is the basis for ecosystem productivity in most marine environments. We report on an ongoing effort to examine whether ambient sounds are tied to chlorophyll levels. We hypothesized that an increase in food-web available energy will be distributed across trophic levels, eventually reaching sound-producing animals and increasing acoustic levels. To test our hypothesis, we compared reef environments to explore links between soundscapes and chlorophyll a concentrations. The study sites resided in disparate oceanographic regimes that experienced substantially different oceanographic conditions. We anticipated that the results would show differing patterns of primary productivity between sites and therefore would be reflected in the soundscapes.

  16. Effects of external phosphorus on the cell ultrastructure and the chlorophyll content of maize under cadmium and zinc stress

    International Nuclear Information System (INIS)

    Jiang, H.M.; Yang, J.C.; Zhang, J.F.

    2007-01-01

    Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis, it was found that the ultrastructure of chloroplasts were changed, the shape of the chloroplasts altered and the numbers of grana that were asymmetrical increased; the numbers of grana and thylakoids decreased under the stress of Cd and Zn. The results indicated that the complex pollution involving Cd and Zn resulted in the membrane system of chloroplasts being damaged. When external phosphorus was applied, the numbers of damaged chloroplasts were significantly reduced and the nucleoli were better formed than those that did not receive phosphorus treatment. Moreover, many phosphate deposits were found in the vacuoles and on the surface of the roots, which were formed by phosphorus complexing with Cd (K sp = 2.53 x 10 -33 ) and Zn (K sp = 9.00 x 10 -33 ), respectively. Treatment with phosphorus conduced an increased chlorophyll content in plants compared with those that did not receive external phosphorus. - External P could decrease the bioavailability of Cd and Zn

  17. Effects of external phosphorus on the cell ultrastructure and the chlorophyll content of maize under cadmium and zinc stress

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, H.M. [Institute of Soil and Fertilizer, CAAS, 100081 Beijing (China); Key Laboratory of Plant Nutrition and Nutrient Cycling, MOA, 100081 Beijing (China); Key Laboratory of Agricultural Nuclear Technology and Aerospace Breeding, MOA, 100094 Beijing (China); Yang, J.C. [Institute of Soil and Fertilizer, CAAS, 100081 Beijing (China) and Key Laboratory of Plant Nutrition and Nutrient Cycling, MOA, 100081 Beijing (China) and Key Laboratory of Agricultural Nuclear Technology and Aerospace Breeding, MOA, 100094 Beijing (China)]. E-mail: yangjch@263.net; Zhang, J.F. [Institute of Soil and Fertilizer, CAAS, 100081 Beijing (China); Key Laboratory of Plant Nutrition and Nutrient Cycling, MOA, 100081 Beijing (China); Key Laboratory of Agricultural Nuclear Technology and Aerospace Breeding, MOA, 100094 Beijing (China)

    2007-06-15

    Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis, it was found that the ultrastructure of chloroplasts were changed, the shape of the chloroplasts altered and the numbers of grana that were asymmetrical increased; the numbers of grana and thylakoids decreased under the stress of Cd and Zn. The results indicated that the complex pollution involving Cd and Zn resulted in the membrane system of chloroplasts being damaged. When external phosphorus was applied, the numbers of damaged chloroplasts were significantly reduced and the nucleoli were better formed than those that did not receive phosphorus treatment. Moreover, many phosphate deposits were found in the vacuoles and on the surface of the roots, which were formed by phosphorus complexing with Cd (K {sub sp} = 2.53 x 10{sup -33}) and Zn (K {sub sp} = 9.00 x 10{sup -33}), respectively. Treatment with phosphorus conduced an increased chlorophyll content in plants compared with those that did not receive external phosphorus. - External P could decrease the bioavailability of Cd and Zn.

  18. Mycosporine-like amino acids in six scleractinian coral species

    OpenAIRE

    Ahmad A. Al-Utaibi; Gul Raze Niaz; Sultan S. Al-Lihaibi*

    2009-01-01

    Mycosporine-like amino acids (MAAs) were studied in stony coral species (Fungiidae) along the Eastern coast of the Red Sea. Six species - Fungia scutaria, F. danai, F. corona, F. repanda, Ctenactis echinata and Lithophyllor lobata - were examined for MAAs at water depths of 5, 10, 15 and 20 m. Protein and chlorophyll were also determined and showed higher contents in winter than in summer. Generally, the total content of MAAs in summer was found to be approximately three times greater than in...

  19. Effect of single varied doses of UV-C radiation on photosynthesis, traspiration and chlorophyll content in the leaves of two varieties of faba bean and pea

    International Nuclear Information System (INIS)

    Olszewski, J.; Pszczolkowska, A.

    2004-01-01

    The effect of single, varied (75, 120 and 165 min) UV-C radiation on photosynthesis and transpiration in leaves of two morphotypes of faba bean and pea was determined in a pot experiment. The SPAD leaf greenness index, which characterises the a and b chlorophyll contents (as well as changes in its content caused by radiation) were analysed. The experimental results indicated that the intensity of photosynthesis and transpiration in faba bean leaves was higher in the plants treated with the UV-C radiation. In addition, the intensity of photosynthesis and the chlorophyll content were higher in the Neptun variety than in the self-terminating faba bean variety. The Rola pea variety plants showed a significant decrease in photsynthesis intensity under radiation in the 3rd leaf phase and a slight decrease in later developmental phases. Moreover, transpiration was found to decrease at the beginning of the vegetation. In the case of the Ramrod variety, rather ambiguous results were obtained. The chlorophyll content in both pea varieties was high in the 3rd proper leaf phase and in the Rola plants it increased with increasing radiation doses in the stem extension phase

  20. Development relationship of color with anthocyanins and chlorophyll content in diferent degrees of maturity of mortiño (Vaccinium floribundum

    Directory of Open Access Journals (Sweden)

    Mónica Arteaga Dalgo

    2014-06-01

    Full Text Available The relationship between color development with anthocyanins and chlorophyll content at different stages of maturity of mortiño (Vaccinum floribundum was studied. The fruits were harvested by surface color from 100% green to 100% black. The color scale was measured according to CIE L* a* b* and color difference (∆E was determined. The anthocyanin and chlorophyll content was performed by UV-VIS spectrophotometry. The following scale was used to establish the stage of maturity: (1 green, (2 green/pink, (3 pink, (4 pink/black and (5 black; It was observed that increasing the maturation stage, the brightness and color saturation decrease. Results showed positive values of a* and negative of b* for maturity stages 3, 4 and 5 (red and blue; and negative values ​​of a * and positive of b * for states 1 and 2 (green and yellow. Smallest differences in color (∆E were found between states 4 and 5. Among the states 1 and 5 was evident a decreased of 0,052 mg/g in chlorophyll content and an increase of 13700mg/kg in anthocyanins. The degree of maturity of the fruit has a direct relationship between the color tone and content of components with antioxidant activity constituting a precedent for future researches and its use of this fruit in different stages of maturity.

  1. The influence of some environmental factors on cytological and biometric parameters and chlorophyll content of Deschampsia antarctica Desv. in the maritime Antarctic.

    Science.gov (United States)

    Parnikoza, I Yu; Loro, P; Miryuta, N Yu; Kunakh, V A; Kozeretska, I A

    2011-01-01

    Under the environmental conditions of the Point Thomas Oasis (King George Island, the South Shetland Islands), we studied the influence of month-long artificial treatment with fresh water, salt water, and guano solution on the biometric characteristics, chlorophyll content, as well as the nuclear area of leaf parenchymal cells and nuclear DNA content, in a maritime Antarctic aboriginal plant Deschampsia antarctica. The modeled factors induced an increase in the generative shoot height and the length of the largest leaf, but did not influence the number of flowers. Treatment with guano caused an increase in the chlorophyll a and b contents, while fresh water treatment only led to some increase in chlorophyll a. Fluctuations of physiologically significant traits, such as the nuclear area and DNA content in the leaf parenchyma cells of D. antarctica, have been traced under the influence of the studied factors. Understanding of the hierarchy of influence of these factors as well as and sensitivity of plants of this species to external agents require further investigation.

  2. Effects of salinity stress on chlorophyll and carotenoid contents and stomata size of grafted and ungrafted galia c8 melon cultivar

    International Nuclear Information System (INIS)

    Yarsi, G.; Sivaci, A.; Dasgan, H.Y.; Altuntas, O.

    2017-01-01

    Salinity is known as the most important abiotic stress that decreases crop production and plant growth, and changes the anatomy and morphology of plants. In this study, the growth rate of grafted and ungrafted melon plants were studied under salinity stress. Maximus F1, Shintoza F-90 F1 and Nun 9075 F1 (Cucurbita maxima x Cucurbita moschata) were used as a rootstock and Galia C8 melon cultivar was used as a scion. In this study, the stomata size and chlorophyll and carotenoid contents were investigated. According to the results, chlorophyll and carotenoid contents and stomata length and width of upper and lower surface of leaf were generally reduced under salinity stress. (author)

  3. Joint leaf chlorophyll content and leaf area index retrieval from Landsat data using a regularized model inversion system (REGFLEC)

    KAUST Repository

    Houborg, Rasmus

    2015-01-19

    Leaf area index (LAI) and leaf chlorophyll content (Chll) represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination, LAI and Chll provide critical information on vegetation density, vitality and photosynthetic potentials. However, simultaneous retrieval of LAI and Chll from space observations is extremely challenging. Regularization strategies are required to increase the robustness and accuracy of retrieved properties and enable more reliable separation of soil, leaf and canopy parameters. To address these challenges, the REGularized canopy reFLECtance model (REGFLEC) inversion system was refined to incorporate enhanced techniques for exploiting ancillary LAI and temporal information derived from multiple satellite scenes. In this current analysis, REGFLEC is applied to a time-series of Landsat data.A novel aspect of the REGFLEC approach is the fact that no site-specific data are required to calibrate the model, which may be run in a largely automated fashion using information extracted entirely from image-based and other widely available datasets. Validation results, based upon in-situ LAI and Chll observations collected over maize and soybean fields in central Nebraska for the period 2001-2005, demonstrate Chll retrieval with a relative root-mean-square-deviation (RMSD) on the order of 19% (RMSD=8.42μgcm-2). While Chll retrievals were clearly influenced by the version of the leaf optical properties model used (PROSPECT), the application of spatio-temporal regularization constraints was shown to be critical for estimating Chll with sufficient accuracy. REGFLEC also reproduced the dynamics of in-situ measured LAI well (r2 =0.85), but estimates were biased low, particularly over maize (LAI was underestimated by ~36 %). This disparity may be attributed to differences between effective and true LAI caused by significant foliage clumping not being properly accounted for in the canopy

  4. Recovery of the coral Montastrea annularis in the Florida Keys after the 1987 Caribbean ``bleaching event''

    Science.gov (United States)

    Fitt, William K.; Spero, Howard J.; Halas, John; White, Michael W.; Porter, James W.

    1993-07-01

    Many reef-building corals and other cnidarians lost photosynthetic pigments and symbiotic algae (zooxanthellae) during the coral bleaching event in the Caribbean in 1987. The Florida Reef Tract included some of the first documented cases, with widespread bleaching of the massive coral Montastrea annularis beginning in late August. Phototransects at Carysfort Reef showed discoloration of >90% of colonies of this species in March 1988 compared to 0% in July 1986; however no mortality was observed between 1986 and 1988. Samples of corals collected in February and June 1988 had zooxanthellae densities ranging from 0.1 in the most lightly colored corals, to 1.6x106 cells/cm2 in the darker corals. Minimum densities increased to 0.5x106 cells/cm2 by August 1989. Chlorophyll- a content of zooxanthellae and zooxanthellar mitotic indices were significantly higher in corals with lower densities of zooxanthellae, suggesting that zooxanthellar at low densities may be more nutrientsufficient than those in unbleached corals. Ash-free dry weight of coral tissue was positively correlated with zooxanthellae density at all sample times and was significantly lower in June 1988 compared to August 1989. Proteins and lipids per cm2 were significantly higher in August 1989 than in February or June, 1988. Although recovery of zooxanthellae density and coral pigmentation to normal levels may occur in less than one year, regrowth of tissue biomass and energy stores lost during the period of low symbiont densities may take significantly longer.

  5. The Effect of Irrigation and Nitrogen on Growth Attributes and Chlorophyll Content of Garlic in Line Source Sprinkler Irrigation System

    Directory of Open Access Journals (Sweden)

    rahim motalebifard

    2017-02-01

    Full Text Available Introduction: With 12 million tons production per year, garlic is the fourth important crop in world. In addition to its medical value, it has been used in food industry. The Hamedan province with 1900 ha cultivation area and 38 percent of production is one of the most important garlic area productions in Iran. Few studies on water use and management of garlic exist in the world. Garlic is very sensitive to water deficit especially in tubers initiation and ripening periods. The current research was done because of scarce research on garlic production under water deficit condition in Iran and importance of plant nutrition and nutrients especially nitrogen on garlic production under stressful conditions. Nitrogen is necessary and important element for increasing the yield and quality of garlic. Application of nitrogen increases the growth trend of garlic such as number of leaves, leaf length and plant body. Reports have shown that garlic has high nitrogen requirement, particularly in the early stages of growth. Materials and Methods: This study was conducted for evaluating the combined effects of nitrogen and irrigation on the yield and quality of garlic (Allium sativumL.. The study was performed as a split-block based on randomized complete blocks design with factors of irrigation at four levels (0-3(normal irrigation, 3-6 (slight water deficit, 6-9 (moderate water deficit and 9-12 (sever water deficit meters distance from main line source sprinkler system, nitrogen at four levels (0, 50,100 and 150 kg nitrogen per ha using three replications and line source sprinkler irrigation system. The total water of irrigation levels was measured by boxes that were fixed in meddle of each plot. The statistical analysis of results were performed using themethod described by Hanks (1980. The chlorophyll index was measured using the chlorophyll meter 502 (Minolta, Spain. The chlorophyll a and bwas measured by the method described by Arnon (1946 and Gross (1991

  6. Qualitative and quantitative studies on phytoplankton and chlorophyll content in the pelagic water of Lake Żarnowieckie in 1974

    Directory of Open Access Journals (Sweden)

    Józefa Sosnowska

    2015-01-01

    Full Text Available Species composition of phytoplankton, its biomass, share of nannoplankton, and concentration of chlorophyll and pheophytin in phytoplankton and nannoplankton were assessed basing on the materials collected from two pelagic stations of Lakę Żarnowieckie during the period 30 March - 6 December 1974. Average and maximal values of phytoplankton biomass (4-5 and 10-11 mg/1 respectively, as well as the concentration of chlorophyll (1.7 -10.0 μg/l together with pheophytin point to slightly advanced eutrophication of the lake. Share of nannoplankton in total phytoplankton biomass was very low (as a rule below 3% with an increase to 15% only in spring. Relatively slight taxonomic differentiation of phytoplankton (164 taxons, its qualitative composition with the predominance of Cyanophyceae in summer, and of Bacillariophyceae in spring and autumn, as also seasonal succession of algae, point to eutrophic character of the lake.

  7. Finding of 13(2) , 17(3) -cyclopheophorbide a enol as a degradation product of chlorophyll in shrunk zooxanthellae of the coral Montipora digitata.

    Science.gov (United States)

    Suzuki, Toshiyuki; Casareto, Beatriz Estela; Shioi, Yuzo; Ishikawa, Yoshio; Suzuki, Yoshimi

    2015-02-01

    We examined the morphology and pigment composition of zooxanthellae in corals subjected to normal temperature (27°C) and thermal stress (32°C). We observed several normal and abnormal morphological types of zooxanthellar cells. Normal cells were intact and their chloroplasts were unbroken (healthy); abnormal cells were shrunken and had partially degraded or broken chloroplasts, or they were bleached and without chloroplasts. At 27°C, most healthy zooxanthellar cells were retained in the coral tissue, whereas shrunken zooxanthellae were expelled. Under thermal stress, the abundance of healthy zooxanthellae declined and the proportion of shrunken/abnormal cells increased in coral tissues. The rate of algal cell expulsion was reduced under thermal stress. Within the shrunken cells, we detected the presence of a chl-like pigment that is not ordinarily found in healthy zooxanthellae. Analysis of the absorption spectrum, absorption maxima, and retention time (by HPLC) indicated that this pigment was 13(2) , 17(3) -cyclopheophorbide a enol (cPPB-aE), which is frequently found in marine and lacustrine sediments, and in protozoans that graze on phytoplankton. The production of cPPB-aE in shrunken zooxanthellae suggests that the chls have been degraded to cPPB-aE, a compound that is not fluorescent. The lack of a fluorescence function precludes the formation of reactive oxygen species. We therefore consider the formation of cPPB-aE in shrunken zooxanthellae to be a mechanism for avoiding oxidative stress. © 2014 The Authors. Journal of Phycology published by Wiley Periodicals, Inc. on behalf of Phycological Society of America.

  8. Manipulation of Contents of Nitrate, Phenolic Acids, Chlorophylls, and Carotenoids in Lettuce (Lactuca sativa L.) via Contrasting Responses to Nitrogen Fertilizer When Grown in a Controlled Environment.

    Science.gov (United States)

    Qadir, Othman; Siervo, Mario; Seal, Chris J; Brandt, Kirsten

    2017-11-22

    This study aimed to use different nitrogen fertilizer regimes to produce Butterhead lettuce with such large differences in nitrate content that they could be used as treatment and placebo to study the effect of inorganic nitrate on human health. Plants were grown under controlled conditions at 27/23 °C day/night with a relatively low photosynthetically active radiation (PAR) of 150 μmol m -2 s -1 for 14 h day -1 and nitrogen supplies ranging from 26 to 154 ppm of N as ammonium nitrate in the fertigation solution. This resulted in contrasting high (∼1078 mg nitrate 100 g -1 FW) or low (∼6 mg 100 g -1 ) nitrate contents in the leaves. Contents of carotenoids and chlorophylls in fresh weight did not differ significantly between the highest and the lowest N-supply levels. However, increased nitrogen supply reduced contents of phenolic compounds from 154 to 22 mg 100 g -1 FW, dry matter content from 8.9% to 4.6%, and fresh weight per plant from 108.52 to 47.57 g/plant FW (all P < 0.001). Thus, while fertilizer treatments can provide lettuce with substantially different nitrate contents, maintaining similar pigment contents (color), they also strongly influence the contents of phenolic acids and flavones.

  9. [Edge effect on lichen's distribution and chlorophyll content, in fragments of Polylepis quadrijuga (Rosaceae) in Páramo de la Rusia (Boyacá-Colombia)].

    Science.gov (United States)

    Pulido Herrera, Karen; Ramos Montaño, Carolina

    2016-12-01

    The ecosystems fragmentation is one of the anthropic phenomena with highest impact at global level and the edge effect causes that only the fragments interior conserve their original biotic and abiotic characteristics. Lichens are organisms especially susceptible to environmental variability, what could be useful for bio-indication of edge effect. In this work, we evaluated the edge effect in two fragments of Polylepis quadrijuga in the Páramo de la Rusia (Boyacá-Colombia) to determine if there is an edge effect on distribution of lichens associated to P. quadrijuga and their chlorophyll content. We used three transects of 70 m across the matrix-edge-interior gradient in each fragment. We chose nine phorophytes per transect to measure the environmental variables: photosynthetically active radiation, relative humidity and air temperature, and the biological variables: richness and cover per species. Besides, we employed the species that were present in all the three zones of the gradient to quantify the content of chlorophylls a and b, and determine if there are changes in the ratio of chlorophylls a/b that could suggest physiological plasticity as a response to the edge effect. Our results showed that fragment 2 had a higher edge exposition because of its high relation perimeter/area, allowing to an environmental homogenization and lose of biodiversity in relation with fragment 1. Overall, we found 55 differentially distributed species in relation with the fragments and the matrix-edge-interior gradient. The interior of fragment 1 was the most conserved zone, harboring a composition different in more than 40 % to the composition of any other zone. We classified the lichens according with their habits: gelatinous, fruticose, crusty or foliose, but we did not find any relationship between the habit distribution and the edge effect. Six species of wide distribution showed changes in the chlorophyll content along the matrix-edge-interior gradient, what is an evidence

  10. Endolithic chlorophyll d-containing phototrophs

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  11. The use of lipids and fatty acids to measure the trophic plasticity of the coral Stylophora subseriata.

    Science.gov (United States)

    Seemann, J; Sawall, Y; Auel, H; Richter, C

    2013-03-01

    Following up on previous investigations on the stress resistance of corals, this study assessed the trophic plasticity of the coral Stylophora subseriata in the Spermonde Archipelago (Indonesia) along an eutrophication gradient. Trophic plasticity was assessed in terms of lipid content and fatty acid composition in the holobiont relative to its plankton (50-300 μm) food as well as the zooxanthellae density, lipid, FA and chlorophyll a content. A cross-transplantation experiment was carried out for 1.5 months in order to assess the trophic potential of corals. Corals, which live in the eutrophied nearshore area showed higher zooxanthellae and chlorophyll a values and higher amounts of the dinoflagellate biomarker FA 18:4n-3. Their lipid contents were maintained at similar to levels from specimens further away from the anthropogenic impact source going up to 14.9 ± 0.9 %. A similarity percentage analysis of the groups holobiont, zooxanthellae and plankton >55 μm found that differences between the FA composition of the holobiont and zooxanthellae symbionts were more distinct in the site closer to the shore, thus heterotrophic feeding became more important. Transplanted corals attained very similar zooxanthellae, chlorophyll a and lipid values at all sites as the specimens originating from those sites, which indicates a high potential for trophic plasticity in the case of a change in food sources, which makes this species competitive and resistant to eutrophication.

  12. Effects of gamma radiation on chlorophyll content of Cladonia verticillaris (Raddi) Fr. (lichen) collected in different environments

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Helena P. de B.; Martins, Monica C.B.; Pereira, Eugenia C.; Barbosa, Clarissa R.; Silva, Nicacio; Franca, Andre Luiz Teixeira de; Colaco, Waldeciro, E-mail: barrosleny@hotmail.com, E-mail: monicabarmartins@hotmail.com, E-mail: verticillaris@gmail.com, E-mail: lissa_fer@hotmail.com, E-mail: nhsilva@uol.com.br, E-mail: wcolaco@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Maciel, Leonardo N. de Q., E-mail: lenoquema@yahoo.com.br [Instituto Federal de Educacao Ciencia e Tecnologia de Pernambuco (IFPE), Vitoria de Santo Antao, PE (Brazil)

    2013-07-01

    Lichens are formed by symbiosis between a fungus (mycobiont) and an alga (photobiont, chloroficeae and or cyanobacteria). The radiosensitivity in lichens is not in proportion to the symbiotic organisms, and the algae layer is more radiosensitive than the fungi. Thus, in order check to algae radiosensitivity, sought to quantify the levels of chlorophyll from C. verticillaris samples with different doses of gamma radiation, since the amount of this pigment is closely related to the percentage of living algal cells. Lichen samples were collected in Saloa-PE and Alhandra- PE, sites that have similar physiognomic characteristics, but with different altitudes. C. verticillaris samples (12 g) of both sampling sites were subjected to gamma irradiator (Co{sup 60} - irradiator, Gammacell 200 Excel, dose rates 7.795 kGy) at 0, 10, 50, 100, 500, 1.000, 5.000 and 10.000 Gy. Lichens samples were collected (1.5 g) and stored separately for further analysis. The results indicated that the total production of chlorophyll in all samples exposed to gamma radiation was lower than non-irradiated samples, demonstrating that way that gamma radiation causes likely to damage/changes in physiological characteristics C. verticillaris. (author)

  13. Effects of gamma radiation on chlorophyll content of Cladonia verticillaris (Raddi) Fr. (lichen) collected in different environments

    International Nuclear Information System (INIS)

    Silva, Helena P. de B.; Martins, Monica C.B.; Pereira, Eugenia C.; Barbosa, Clarissa R.; Silva, Nicacio; Franca, Andre Luiz Teixeira de; Colaco, Waldeciro; Maciel, Leonardo N. de Q.

    2013-01-01

    Lichens are formed by symbiosis between a fungus (mycobiont) and an alga (photobiont, chloroficeae and or cyanobacteria). The radiosensitivity in lichens is not in proportion to the symbiotic organisms, and the algae layer is more radiosensitive than the fungi. Thus, in order check to algae radiosensitivity, sought to quantify the levels of chlorophyll from C. verticillaris samples with different doses of gamma radiation, since the amount of this pigment is closely related to the percentage of living algal cells. Lichen samples were collected in Saloa-PE and Alhandra- PE, sites that have similar physiognomic characteristics, but with different altitudes. C. verticillaris samples (12 g) of both sampling sites were subjected to gamma irradiator (Co 60 - irradiator, Gammacell 200 Excel, dose rates 7.795 kGy) at 0, 10, 50, 100, 500, 1.000, 5.000 and 10.000 Gy. Lichens samples were collected (1.5 g) and stored separately for further analysis. The results indicated that the total production of chlorophyll in all samples exposed to gamma radiation was lower than non-irradiated samples, demonstrating that way that gamma radiation causes likely to damage/changes in physiological characteristics C. verticillaris. (author)

  14. Effect of pre-harvest foliar application of citric acid and malic acid on chlorophyll content and post-harvest vase life of Lilium cv. Brunello

    Directory of Open Access Journals (Sweden)

    Nafiseh eDarandeh

    2012-01-01

    Full Text Available Preharvest use of citric acid is a novel method in vase life extension of cut flowers, which is reported on tuberose earlier and confirmed here on lilium. In this research citric acid (0, 0.075, 0.15 percent v/v and malic acid (0, 0.075, 0.15 percent v/v were used together two times during growth period of lilium plants in a randomized factorial design with three replications. The results point out that 0.15% citric acid had increased vase life from 13.1 to 14 days (α=0.05. The interesting finding was the effect of citric acid on bulbil weight, which was decreased from 8.6 gr to 2.9 gr in 0.15% citric acid per cut flower. Malic acid while having no effect on pre-mentioned traits surprisingly increased the chlorophyll content significantly. The interaction effect between citric acid and malic acid on vase life and chlorophyll content proved significant and was evident in results both as antagonistic and synergistic in various traits. In mean comparison of factor-levels, the effect of citric acid on vase-life extension was more prominent increasing it from 11.8 to 14.3 days in treatment with 0.15% citric acid and without malic acid compared to control treatment.

  15. Identification of new SSR markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat under water stressed condition.

    Science.gov (United States)

    Barakat, Mohamed N; Saleh, Mohamed; Al-Doss, Abdullah A; Moustafa, Khaled A; Elshafei, Adel A; Al-Qurainy, Fahed H

    2015-03-01

    Segregating F4 families from the cross between drought sensitive (Yecora Rojo) and drought tolerant (Pavon 76) genotypes were made to identify SSR markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat (Triticum aestivum L.) under water-stressed condition and to map quantitative trait locus (QTL) for the three physiological traits. The parents and 150 F4 families were evaluated phenotypically for drought tolerance using two irrigation treatments (2500 and 7500 m3/ha). Using 400 SSR primers tested for polymorphism in testing parental and F4 families genotypes, the results revealed that QTL for leaf chlorophyll content, flag leaf senescence and cell membrane stability traits were associated with 12, 5 and 12 SSR markers, respectively and explained phenotypic variation ranged from 6 to 42%. The SSR markers for physiological traits had genetic distances ranged from 12.5 to 25.5 cM. These SSR markers can be further used in breeding programs for drought tolerance in wheat.

  16. Heavy metal contents in growth bands of Porites corals: Record of anthropogenic and human developments from the Jordanian Gulf of Aqaba

    International Nuclear Information System (INIS)

    Al-Rousan, Saber A.; Al-Shloul, Rashid N.; Al-Horani, Fuad A.; Abu-Hilal, Ahmad H.

    2007-01-01

    In order to assess pollutants and impact of environmental changes in the coastal region of the Jordanian Gulf of Aqaba, concentrations of six metals were traced through variations in 5 years growth bands sections of recent Porties coral skeleton. X-radiography showed annual growth band patterns extending back to the year 1925. Baseline metal concentrations in Porites corals were established using 35 years-long metal record from late Holocene coral (deposited in pristine environment) and coral from reef that is least exposed to pollution in the marine reserve in the Gulf of Aqaba. The skeleton samples of the collected corals were acid digested and analyzed for their Cd, Cu, Fe, Mn, Pb and Zn content using Flame Atomic Absorption Spectrophotometer (FAAS). All metal profiles (except Fe and Zn) recorded the same metal signature from recent coral (1925-2005) in which low steady baseline levels were displayed in growth bands older than 1965, similar to those obtained from fossil and unpolluted corals. Most metals showed dramatic increase (ranging from 17% to 300%) in growth band sections younger than 1965 suggesting an extensive contamination of the coastal area since the mid sixties. This date represents the beginning of a period that witnessed increasing coastal activities, constructions and urbanization. This has produced a significant reduction in coral skeletal extension rates. Results from this study strongly suggest that Porites corals have a high tendency to accumulate heavy metals in their skeletons and therefore can serve as proxy tools to monitor and record environmental pollution (bioindicators) in the Gulf of Aqaba

  17. Heavy metal contents in growth bands of Porites corals: Record of anthropogenic and human developments from the Jordanian Gulf of Aqaba

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rousan, Saber A. [Marine Science Station, University of Jordan and Yarmouk University, P.O. Box 195, Aqaba 77110 (Jordan)], E-mail: s.rousan@ju.edu.jo; Al-Shloul, Rashid N. [Department of Earth and Environmental Science, Faculty of Science, Yarmouk University, Irbid 21163 (Jordan); Al-Horani, Fuad A. [Marine Science Station, University of Jordan and Yarmouk University, P.O. Box 195, Aqaba 77110 (Jordan); Abu-Hilal, Ahmad H. [Department of Earth and Environmental Science, Faculty of Science, Yarmouk University, Irbid 21163 (Jordan)

    2007-12-15

    In order to assess pollutants and impact of environmental changes in the coastal region of the Jordanian Gulf of Aqaba, concentrations of six metals were traced through variations in 5 years growth bands sections of recent Porties coral skeleton. X-radiography showed annual growth band patterns extending back to the year 1925. Baseline metal concentrations in Porites corals were established using 35 years-long metal record from late Holocene coral (deposited in pristine environment) and coral from reef that is least exposed to pollution in the marine reserve in the Gulf of Aqaba. The skeleton samples of the collected corals were acid digested and analyzed for their Cd, Cu, Fe, Mn, Pb and Zn content using Flame Atomic Absorption Spectrophotometer (FAAS). All metal profiles (except Fe and Zn) recorded the same metal signature from recent coral (1925-2005) in which low steady baseline levels were displayed in growth bands older than 1965, similar to those obtained from fossil and unpolluted corals. Most metals showed dramatic increase (ranging from 17% to 300%) in growth band sections younger than 1965 suggesting an extensive contamination of the coastal area since the mid sixties. This date represents the beginning of a period that witnessed increasing coastal activities, constructions and urbanization. This has produced a significant reduction in coral skeletal extension rates. Results from this study strongly suggest that Porites corals have a high tendency to accumulate heavy metals in their skeletons and therefore can serve as proxy tools to monitor and record environmental pollution (bioindicators) in the Gulf of Aqaba.

  18. Phytoplankton chlorophyll

    NARCIS (Netherlands)

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

    2013-01-01

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

  19. Metabolomics reveals biotic and abiotic elicitor effects on the soft coral Sarcophyton ehrenbergi terpenoid content

    OpenAIRE

    Farag, Mohamed A.; Al-Mahdy, Dalia A.; Meyer, Achim; Westphal, Hildegard; Wessjohann, Ludger A.

    2017-01-01

    The effects of six biotic and abiotic elicitors, i.e. MeJA (methyl jasmonate), SA (salicylic acid), ZnCl2, glutathione and ?-glucan BG (fungal elicitor), and wounding, on the secondary metabolite accumulation in the soft coral Sarcophyton ehrenbergi were assessed. Upon elicitation, metabolites were extracted and analysed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Except for MeJA, no differences in photosynthetic efficiency were observed after treatments, suggestin...

  20. The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.

    Directory of Open Access Journals (Sweden)

    Tamar L Goulet

    Full Text Available Global climate change not only leads to elevated seawater temperatures but also to episodic anomalously high or low temperatures lasting for several hours to days. Scleractinian corals are detrimentally affected by thermal fluctuations, which often lead to an uncoupling of their mutualism with Symbiodinium spp. (coral bleaching and potentially coral death. Consequently, on many Caribbean reefs scleractinian coral cover has plummeted. Conversely, gorgonian corals persist, with their abundance even increasing. How gorgonians react to thermal anomalies has been investigated utilizing limited parameters of either the gorgonian, Symbiodinium or the combined symbiosis (holobiont. We employed a holistic approach to examine the effect of an experimental five-day elevated temperature episode on parameters of the host, symbiont, and the holobiont in Eunicea tourneforti, E. flexuosa and Pseudoplexaura porosa. These gorgonian corals reacted and coped with 32°C seawater temperatures. Neither Symbiodinium genotypes nor densities differed between the ambient 29.5°C and 32°C. Chlorophyll a and c2 per Symbiodinium cell, however, were lower at 32°C leading to a reduction in chlorophyll content in the branches and an associated reduction in estimated absorbance and increase in the chlorophyll a specific absorption coefficient. The adjustments in the photochemical parameters led to changes in photochemical efficiencies, although these too showed that the gorgonians were coping. For example, the maximum excitation pressure, Qm, was significantly lower at 32°C than at 29.5°C. In addition, although per dry weight the amount of protein and lipids were lower at 32°C, the overall energy content in the tissues did not differ between the temperatures. Antioxidant activity either remained the same or increased following exposure to 32°C further reiterating a response that dealt with the stressor. Taken together, the capability of Caribbean gorgonian corals to modify

  1. Effect of gamma radiation on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa; Efecto de la radiacion gamma sobre la fotosintesis neta y la respiracion de Chlorella pyrenoidosa

    Energy Technology Data Exchange (ETDEWEB)

    Martin, C; Fernandez, J

    1983-07-01

    The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa has been studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and 5000 Gy, being, at first b chlorophyll affected to a greater extent than a chlorophyll. Net photosynthesis and respiration decline throughout the time of the observation after irradiation, this depressing effect being much more remarkable for the first one. Met photosynthesis inhibition levels of about 30% are got only five hours post irradiation at a dose of 5000 Gy. Radio estimation by low doses, although obtained in some cases for tho 10 Gy dose, has not been statistically confirmed. (Author) 23 refs.

  2. Effects of nutrient enrichment on the release of dissolved organic carbon and nitrogen by the scleractinian coral Montipora digitata

    Science.gov (United States)

    Tanaka, Y.; Ogawa, H.; Miyajima, T.

    2010-09-01

    The effects of nutrient enrichment on the release of dissolved organic carbon and nitrogen (DOC and DON, respectively) from the coral Montipora digitata were investigated in the laboratory. Nitrate (NO3 -) and phosphate (PO4 3-) were supplied to the aquarium to get the final concentrations of 10 and 0.5 μmol l-1, respectively, and the corals were incubated for 8 days. The release rate of DON per unit coral surface area significantly decreased after the nutrient enrichment, while the release rate of DOC was constant. Because the chlorophyll a (chl a) content of zooxanthellae per unit surface area increased, the release rate of DOC significantly decreased when normalized to unit chl a. These results suggested that the incorporation of NO3 - and PO4 3- stimulated the synthesis of new cellular components in the coral colonies and consequently, reduced extracellular release of DOC and DON. Actually, significant increase in N and P contents relative to C content was observed in the coral’s tissue after the nutrient enrichment. The present study has concluded that inorganic nutrient enrichment not only affects coral-algal metabolism inside the colony but also affects a microbial community around the coral because the organic matter released from corals functions as energy carrier in the coral reef ecosystem.

  3. Cumulative effect of zinc oxide and titanium oxide nanoparticles on growth and chlorophyll a content of Picochlorum sp.

    Science.gov (United States)

    Hazeem, Layla J; Bououdina, Mohammed; Rashdan, Suad; Brunet, Loïc; Slomianny, Christian; Boukherroub, Rabah

    2016-02-01

    The use of nanoparticles (NPs) is of increasing significance due to their large potential for various applications. Great attention should be paid on the possible impacts of nanoparticles on the environment as large amounts of them may reach the environment by accident or voluntarily. Marine algae are potential organisms for usage in nanopollution bioremediation in aquatic system, because of their ability to adapt to long exposure to NPs. Thus, it is of prime importance to study the possible interactions of different NPs with microalgae in assessing their potential environmental risks. Most studies on potential environmental effects of ZnO and TiO2 NPs have been performed independently and following the widely accepted, standardized test systems, which had been developed for the characterization of chemicals. In this study, we have examined the cumulative effect of ZnO and TiO2 NPs on Picochlorum sp. in addition to the individual effects of these NPs over 32 days. Our results indicate that the toxicity and availability of NPs to marine algae are reduced by their aggregation and sedimentation. NPs are found to have a negative effect on algal growth and chlorophyll a concentration during the early growth stages. In contrast, the case is reversed during the late growth stages. There is no significant difference between the effect of the NPs when they are used separately and when both ZnO and TiO2 are used together in the test (P > 0.05).

  4. Plant growth-promoting bacterium Acinetobacter calcoaceticus P23 increases the chlorophyll content of the monocot Lemna minor (duckweed) and the dicot Lactuca sativa (lettuce).

    Science.gov (United States)

    Suzuki, Wakako; Sugawara, Masayuki; Miwa, Kyoko; Morikawa, Masaaki

    2014-07-01

    Acinetobacter calcoaceticus P23 is a plant growth-promoting bacterium that was isolated from the surface of duckweed (Lemna aoukikusa). The bacterium was observed to colonize on the plant surfaces and increase the chlorophyll content of not only the monocotyledon Lemna minor but also the dicotyledon Lactuca sativa in a hydroponic culture. This effect on the Lactuca sativa was significant in nutrient-poor (×1/100 dilution of H2 medium) and not nutrient-rich (×1 or ×1/10 dilutions of H2 medium) conditions. Strain P23 has the potential to play a part in the future development of fertilizers and energy-saving hydroponic agricultural technologies. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Acetyl salicylic acid and 24-epibrassinolide attenuate decline in photosynthesis, chlorophyll contents and membrane thermo- stability in tomato (lycopersicon esculentum mill.) under heat stress

    International Nuclear Information System (INIS)

    Khan, A.R.; Hui, C.Z.; Ghazanfar, B.

    2015-01-01

    The effect of exogenous application of varying levels of 24-epibrassinolide (0.75, 1.5 and 3 micro M) and acetyl salicylic acid (0.25, 0.75 and 1.25 micro M) for induction of heat tolerance in terms of their effect on photosynthesis, chlorophyll content, membrane integrity and survival in four weeks old tomato (cultivar: Mei Jie Lo) seedlings under high temperature stress (46 degree C/4 h daily) for 21 days was investigated. The daily heat stress treatment had deleterious effects on seedlings but chemical treatments significantly reduced the magnitude of losses to different extents. 24-epibrassinolide (3 micro M) was over all the best treatment to improve survival (86.11%), photosynthesis (39.4%) and chlorophyll contents (26.12%) accompanied with initiation of flower buds and improved vegetative growth. Whereas acetyl salicylic acid (1.25 mM) best improved photosynthetic activity (40.6%) as compared to the untreated heat stressed control seedlings. Moreover, 3 micro M 24-epibrassinolide and 0.75 micro M acetyl salicylic acid reduced cell membrane injury to 8.3 and 6.9% respectively as compared with 22.4% in heat stressed control seedlings. However lower doses of acetyl salicylic acid (0.25 and 0.75 micro M) had slight (5.6 and 12.8%) inhibition effect on the photosynthesis than the heat stressed controls. Overall both acetyl salicylic acid and 24-epibrassinolide up regulated basal heat tolerance in tomato seedlings and studied concentrations demonstrated signature affect upon different parameters. Thus both chemical agents can be potential candidates for further investigations for exogenous application aiming at extension of tomato growth season in summer. (author)

  6. Adaptive changes in chlorophyll content and photosynthetic features to low light in Physocarpus amurensis Maxim and Physocarpus opulifolius “Diabolo”

    Science.gov (United States)

    Zhang, Huihui; Zhong, Haixiu; Wang, JIfeng; Sui, Xin

    2016-01-01

    The present study aims to investigate the differences in leaf pigment content and the photosynthetic characteristics under natural and low light intensities between the Chinese native Physocarpus amurensis Maxim and the imported Physocarpus opulifolius “Diabolo” from North America. We aim to discuss the responses and the adaptive mechanism of these two cultivars of Physocarpus to a low light environment. The results show that the specific leaf area (SLA) and the chlorophyll content were significantly increased in the leaves of both Physocarpus cultivars in response to a low light intensity, and the SLA and chlorophyll content were higher in the leaves of low light-treated P. opulifolius “Diabolo” compared with the leaves of low light-treated P. amurensis Maxim. Moreover, the content of anthocyanin was markedly reduced in the leaves of P. opulifolius “Diabolo” under low light intensity, which allowed for a greater capacity of photon capture under the low light condition. Under natural light, the photosynthetic carbon assimilation capacity was greater in the leaves of P. amurensis Maxim compared with the leaves of P. opulifolius “Diabolo” that were rich with anthocyanin. However, in response to low light, AQY, Pmax, LCP and LSP decreased to a lesser extent in the leaves of P. opulifolius “Diabolo” compared with the leaves of P. amurensis Maxim. These results suggest that P. opulifolius “Diabolo” exhibits a greater ability in adaption to low light, and it is probably related to the relatively higher chlorophyll content and the smaller SLA in the leaves of P. opulifolius “Diabolo.” In addition, the low light intensity resulted in a reduced photochemical activity of photosystem (PS) II in the leaves of both Physocarpus, as evidenced by increased values of the relative variable fluorescence at point J and point I on the OJIP curve. This result suggests that the electron acceptor in PS II was the major responsive site to the low light stress in

  7. Adaptive changes in chlorophyll content and photosynthetic features to low light in Physocarpus amurensis Maxim and Physocarpus opulifolius “Diabolo”

    Directory of Open Access Journals (Sweden)

    Huihui Zhang

    2016-06-01

    Full Text Available The present study aims to investigate the differences in leaf pigment content and the photosynthetic characteristics under natural and low light intensities between the Chinese native Physocarpus amurensis Maxim and the imported Physocarpus opulifolius “Diabolo” from North America. We aim to discuss the responses and the adaptive mechanism of these two cultivars of Physocarpus to a low light environment. The results show that the specific leaf area (SLA and the chlorophyll content were significantly increased in the leaves of both Physocarpus cultivars in response to a low light intensity, and the SLA and chlorophyll content were higher in the leaves of low light-treated P. opulifolius “Diabolo” compared with the leaves of low light-treated P. amurensis Maxim. Moreover, the content of anthocyanin was markedly reduced in the leaves of P. opulifolius “Diabolo” under low light intensity, which allowed for a greater capacity of photon capture under the low light condition. Under natural light, the photosynthetic carbon assimilation capacity was greater in the leaves of P. amurensis Maxim compared with the leaves of P. opulifolius “Diabolo” that were rich with anthocyanin. However, in response to low light, AQY, Pmax, LCP and LSP decreased to a lesser extent in the leaves of P. opulifolius “Diabolo” compared with the leaves of P. amurensis Maxim. These results suggest that P. opulifolius “Diabolo” exhibits a greater ability in adaption to low light, and it is probably related to the relatively higher chlorophyll content and the smaller SLA in the leaves of P. opulifolius “Diabolo.” In addition, the low light intensity resulted in a reduced photochemical activity of photosystem (PS II in the leaves of both Physocarpus, as evidenced by increased values of the relative variable fluorescence at point J and point I on the OJIP curve. This result suggests that the electron acceptor in PS II was the major responsive site to the

  8. Comparison of leaf color chart observations with digital photographs and spectral measurements for estimating maize leaf chlorophyll content

    Science.gov (United States)

    Crop nitrogen management is important world-wide, as much for small fields as it is for large operations. Developed as a non-destructive aid for estimating nitrogen content in rice crops, leaf color charts (LCC) are a numbered series of plastic panels that range from yellowgreen to dark green. By vi...

  9. Processed vs. non-processed biowastes for agriculture: effects of post-harvest tomato plants and biochar on radish growth, chlorophyll content and protein production.

    Science.gov (United States)

    Mozzetti Monterumici, Chiara; Rosso, Daniele; Montoneri, Enzo; Ginepro, Marco; Baglieri, Andrea; Novotny, Etelvino Henrique; Kwapinski, Witold; Negre, Michèle

    2015-04-21

    The aim of this work was to address the issue of processed vs. non-processed biowastes for agriculture, by comparing materials widely differing for the amount of process energy consumption. Thus, residual post harvest tomato plants (TP), the TP hydrolysates obtained at pH 13 and 60 °C, and two known biochar products obtained by 650 °C pyrolysis were prepared. All products were characterized and used in a cultivation of radish plants. The chemical composition and molecular nature of the materials was investigated by solid state 13C NMR spectrometry, elemental analysis and potentiometric titration. The plants were analysed for growth and content of chlorophyll, carotenoids and soluble proteins. The results show that the TP and the alkaline hydrolysates contain lignin, hemicellulose, protein, peptide and/or amino acids moieties, and several mineral elements. The biochar samples contain also similar mineral elements, but the organic fraction is characterized mainly by fused aromatic rings. All materials had a positive effect on radish growth, mainly on the diameter of roots. The best performances in terms of plant growth were given by miscanthus originated biochar and TP. The most significant effect was the enhancement of soluble protein content in the plants treated with the lowest energy consumption non processed TP. The significance of these findings for agriculture and the environment is discussed.

  10. Effects of abscisic acid or benzyladenine on pigment contents, chlorophyll fluorescence, and chloroplast ultrastructure during water stress and after rehydration

    Czech Academy of Sciences Publication Activity Database

    Haisel, Daniel; Pospíšilová, Jana; Synková, Helena; Schnablová, Renáta; Baťková, Petra

    2006-01-01

    Roč. 44, č. 4 (2006), s. 606-614 ISSN 0300-3604 R&D Projects: GA ČR GA522/04/0549 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : Beta vulgaris * Nicotiana tabacum * Phaseolus vulgaris * starch content * Zea mays Subject RIV: ED - Physiology Impact factor: 0.782, year: 2006

  11. Indicators: Chlorophyll a

    Science.gov (United States)

    Chlorophyll allows plants (including algae) to photosynthesize, i.e., use sunlight to convert simple molecules into organic compounds. Chlorophyll a is the predominant type of chlorophyll found in green plants and algae.

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

    Directory of Open Access Journals (Sweden)

    Kaouther Zhani

    2012-11-01

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

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

    Science.gov (United States)

    Wu, Huanyang

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Huanyang Wu

    2016-01-01

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

  15. Effects of light, food availability and temperature stress on the function of photosystem II and photosystem I of coral symbionts.

    Directory of Open Access Journals (Sweden)

    Mia O Hoogenboom

    Full Text Available Reef corals are heterotrophic coelenterates that achieve high productivity through their photosynthetic dinoflagellate symbionts. Excessive seawater temperature destabilises this symbiosis and causes corals to "bleach," lowering their photosynthetic capacity. Bleaching poses a serious threat to the persistence of coral reefs on a global scale. Despite expanding research on the causes of bleaching, the mechanisms remain a subject of debate.This study determined how light and food availability modulate the effects of temperature stress on photosynthesis in two reef coral species. We quantified the activities of Photosystem II, Photosystem I and whole chain electron transport under combinations of normal and stressful growth temperatures, moderate and high light levels and the presence or absence of feeding of the coral hosts. Our results show that PS1 function is comparatively robust against temperature stress in both species, whereas PS2 and whole chain electron transport are susceptible to temperature stress. In the symbiotic dinoflagellates of Stylophora pistillata the contents of chlorophyll and major photosynthetic complexes were primarily affected by food availability. In Turbinaria reniformis growth temperature was the dominant influence on the contents of the photosynthetic complexes. In both species feeding the host significantly protected photosynthetic function from high temperature stress.Our findings support the photoinhibition model of coral bleaching and demonstrate that PS1 is not a major site for thermal damage during bleaching events. Feeding mitigates bleaching in two scleractinian corals, so that reef responses to temperature stresses will likely be influenced by the coinciding availabilities of prey for the host.

  16. Red light represses the photophysiology of the scleractinian coral Stylophora pistillata.

    Science.gov (United States)

    Wijgerde, Tim; van Melis, Anne; Silva, Catarina I F; Leal, Miguel C; Vogels, Luc; Mutter, Claudia; Osinga, Ronald

    2014-01-01

    Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the individual and combined effects of blue and red light on the health, zooxanthellae density, photophysiology and colouration of the scleractinian coral Stylophora pistillata over 6 weeks. Coral fragments were exposed to blue, red, and combined 50/50% blue red light, at two irradiance levels (128 and 256 μmol m(-2) s(-1)). Light spectrum affected the health/survival, zooxanthellae density, and NDVI (a proxy for chlorophyll a content) of S. pistillata. Blue light resulted in highest survival rates, whereas red light resulted in low survival at 256 μmol m(-2) s(-1). Blue light also resulted in higher zooxanthellae densities compared to red light at 256 μmol m(-2) s(-1), and a higher NDVI compared to red and combined blue red light. Overall, our results suggest that red light negatively affects the health, survival, symbiont density and NDVI of S. pistillata, with a dominance of red over blue light for NDVI.

  17. Red light represses the photophysiology of the scleractinian coral Stylophora pistillata.

    Directory of Open Access Journals (Sweden)

    Tim Wijgerde

    Full Text Available Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the individual and combined effects of blue and red light on the health, zooxanthellae density, photophysiology and colouration of the scleractinian coral Stylophora pistillata over 6 weeks. Coral fragments were exposed to blue, red, and combined 50/50% blue red light, at two irradiance levels (128 and 256 μmol m(-2 s(-1. Light spectrum affected the health/survival, zooxanthellae density, and NDVI (a proxy for chlorophyll a content of S. pistillata. Blue light resulted in highest survival rates, whereas red light resulted in low survival at 256 μmol m(-2 s(-1. Blue light also resulted in higher zooxanthellae densities compared to red light at 256 μmol m(-2 s(-1, and a higher NDVI compared to red and combined blue red light. Overall, our results suggest that red light negatively affects the health, survival, symbiont density and NDVI of S. pistillata, with a dominance of red over blue light for NDVI.

  18. Red Light Represses the Photophysiology of the Scleractinian Coral Stylophora pistillata

    Science.gov (United States)

    Wijgerde, Tim; van Melis, Anne; Silva, Catarina I. F.; Leal, Miguel C.; Vogels, Luc; Mutter, Claudia; Osinga, Ronald

    2014-01-01

    Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the individual and combined effects of blue and red light on the health, zooxanthellae density, photophysiology and colouration of the scleractinian coral Stylophora pistillata over 6 weeks. Coral fragments were exposed to blue, red, and combined 50/50% blue red light, at two irradiance levels (128 and 256 μmol m−2 s−1). Light spectrum affected the health/survival, zooxanthellae density, and NDVI (a proxy for chlorophyll a content) of S. pistillata. Blue light resulted in highest survival rates, whereas red light resulted in low survival at 256 μmol m−2 s−1. Blue light also resulted in higher zooxanthellae densities compared to red light at 256 μmol m−2 s−1, and a higher NDVI compared to red and combined blue red light. Overall, our results suggest that red light negatively affects the health, survival, symbiont density and NDVI of S. pistillata, with a dominance of red over blue light for NDVI. PMID:24658108

  19. O SPAD-502 como alternativa para a determinação dos teores de clorofila em espécies frutíferas The SPAD-502 as alternative for determining chlorophyll content in fruit tree species

    Directory of Open Access Journals (Sweden)

    Simone Verdes de Jesus

    2008-12-01

    Full Text Available A relação entre o teor absoluto de clorofila e o teor relativo de clorofila obtido pelo SPAD-502 foi determinada em quatro espécies frutíferas (cupuaçu, araçá-boi, limão e urucum. O teor absoluto de clorofila foi determinado usando um espectrofotômetro após a extração dos pigmentos em acetona 80%. O teor de clorofila total (y foi relacionado com os valores do SPAD (x, como segue: y = 93,95e0,0356x, r² = 0,80 para o urucum; y = 125,41e0,0205x, r² = 0,67 para o cupuaçu; y = 67,58e0,0374x, r² = 0,80 para o limão e y = 66,96e0,0365x, r² = 0,92 para o araçá-boi.The relationship between the absolute chlorophyll content and the relative chlorophyll content (SPAD-502 values was determined in four fruit trees species (cupuassu, araza, lemon, and annato. The absolute chlorophyll content was determined using a spectrophotometer after pigment extraction in 80% acetone. Chlorophyll content (y was related to SPAD values (x as follows: y = 93.95e0.0356x, r² = 0.80 for annato; y =125.41e0.0205x, r² = 0.67 for cupuassu; y =67.58e0.0374x, r² = 0.80 for lemon and y =66.96e0.0365x, r² = 0.92 for araza.

  20. Identification of Genes Associated with Chlorophyll Accumulation in Flower Petals

    Science.gov (United States)

    Ohmiya, Akemi; Hirashima, Masumi; Yagi, Masafumi; Tanase, Koji; Yamamizo, Chihiro

    2014-01-01

    Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of genes related to chlorophyll metabolism in different stages of non-green (red and white) petals (very low chlorophyll content), pale-green petals (low chlorophyll content), and leaves (high chlorophyll content) of carnation (Dianthus caryophyllus L.). The expression of many genes encoding chlorophyll biosynthesis enzymes, in particular Mg-chelatase, was lower in non-green petals than in leaves. Non-green petals also showed higher expression of genes involved in chlorophyll degradation, including STAY-GREEN gene and pheophytinase. These data suggest that the absence of chlorophylls in carnation petals may be caused by the low rate of chlorophyll biosynthesis and high rate of degradation. Similar results were obtained by the analysis of Arabidopsis microarray data. In carnation, most genes related to chlorophyll biosynthesis were expressed at similar levels in pale-green petals and leaves, whereas the expression of chlorophyll catabolic genes was higher in pale-green petals than in leaves. Therefore, we hypothesize that the difference in chlorophyll content between non-green and pale-green petals is due to different levels of chlorophyll biosynthesis. Our study provides a basis for future molecular and genetic studies on organ-specific chlorophyll accumulation. PMID:25470367

  1. Changes in scleractinian coral Seriatopora hystrix morphology and its endocellular Symbiodinium characteristics along a bathymetric gradient from shallow to mesophotic reef

    Science.gov (United States)

    Nir, O.; Gruber, D. F.; Einbinder, S.; Kark, S.; Tchernov, D.

    2011-12-01

    The algae living endosymbiotically within coral are thought to increase algal pigmentation with increasing depth to capture the diminishing light. Here, we follow distribution of the hermatypic coral Seriatopora hystrix along a 60-m bathymetric gradient in the Gulf of Eilat, Red Sea, to study coral ecophysiology and response to light regimes. Combining work on coral morphology, pigment content and genotyping of the photosymbiont, we found that total chlorophyll concentration per zooxanthellae cell and the dark- and light-acclimated quantum yield of photosystem II did not vary significantly along the 60-m gradient. However, the chlorophyll a/c ratio increased with depth. This suggests that the symbiotic algae in S. hystrix possess a mechanism for acclimatization or adaptation that differs from previously described pathways. The accepted photoacclimatory process involves an increase in chlorophyll content per alga as light intensity decreases. Based on corallite and branch morphology, this research suggests that S. hystrix has two depth-dependent ecophenotypes. Above 10 m depth, S. hystrix exhibits sturdier colony configurations with thick branches, while below 30 m depth, colonies are characterized by thin branches and the presence of a larger polyp area. Between 10 and 30 m depth, both ecophenotypes are present, suggesting that corallite morphology may act as another axis of photoacclimation with depth.

  2. Estimativa do teor de nitrogênio em arroz irrigado com o clorofilômetro e a cartela de cores Nitrogen content estimative in flooded rice by using of chlorophyll meter and color chart

    Directory of Open Access Journals (Sweden)

    Elisandra Pocojeski

    2012-11-01

    Full Text Available O clorofilômetro e a cartela de cores têm sido utilizados para monitorar a adubação nitrogenada em diferentes culturas, com o pressuposto de que há uma relação entre suas leituras e o teor de nitrogênio (N no tecido das plantas. O objetivo deste trabalho foi avaliar a utilização do clorofilômetro e da cartela de cores na estimativa do teor de N em folhas de arroz irrigado por alagamento. Foram utilizados dois experimentos instalados em um Planossolo Háplico, sendo o primeiro conduzido com cinco doses de N (0, 50, 80, 120 e 160kg ha-1 na forma de ureia e a cultivar 'IRGA 417', e o segundo com seis cultivares de arroz irrigado de diferentes ciclos ('BR-IRGA 409', 'BR-IRGA 410', 'IRGA 417', 'IRGA 421', 'EPAGRI 108' e 'HÍBRIDO 2' com uma única dose de N. Foram realizadas avaliações com clorofilômetro e a cartela de cores nas folhas do arroz em diferentes épocas. Simultaneamente às leituras, foram coletadas amostras de folhas e nelas determinado o teor de N. Quando variaram as doses de N, houve correlação significativa entre as leituras do clorofilômetro e da cartela de cores com o teor de N nas folhas, independente da época de avaliação. Já quando variaram as cultivares, as leituras do clorofilômetro se correlacionaram com o teor de N (r=0,78; PThe chlorophyll meter and the color chart have been applied to monitor nitrogen fertilization in different crops, based on the assumption that there is a correlation between their readings and the nitrogen content (N in the plant tissue. This research aims at assessing the use of the chlorophyll meter and the color chart to estimate the N content in leaves of flooded rice plants. Two experiments installed at a Albaqualf (Planossolo Háplico were used, the first using five N doses (0, 50, 80, 120 and 160kg ha-1 as urea and the cultivar 'IRGA 417', and the second with six flooded rice cultivars of different cycles ('BR-IRGA 409', 'BR-IRGA 410', 'IRGA 417', 'IRGA 421', 'EPAGRI 108' and

  3. Changes in the Chlorophyll Content and Cytokinin Levels in the Top Three Leaves of New Plant Type Rice During Grain Filling

    Czech Academy of Sciences Publication Activity Database

    Rubia, L.; Rangan, L.; Kamínek, Miroslav; Dobrev, Petre; Malbeck, Jiří; Fowler, M.; Khush, G.; Elliott, M.

    2014-01-01

    Roč. 33, č. 1 (2014), s. 66-76 ISSN 0721-7595 R&D Projects: GA MŠk 1M06030 Institutional support: RVO:61389030 Keywords : Chlorophyll * Cytokinins * Grain filling Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.237, year: 2014

  4. Improved estimation of leaf area index and leaf chlorophyll content of a potato crop using multi-angle spectral data - potential of unmanned aerial vehicle imagery

    Science.gov (United States)

    Roosjen, Peter P. J.; Brede, Benjamin; Suomalainen, Juha M.; Bartholomeus, Harm M.; Kooistra, Lammert; Clevers, Jan G. P. W.

    2018-04-01

    In addition to single-angle reflectance data, multi-angular observations can be used as an additional information source for the retrieval of properties of an observed target surface. In this paper, we studied the potential of multi-angular reflectance data for the improvement of leaf area index (LAI) and leaf chlorophyll content (LCC) estimation by numerical inversion of the PROSAIL model. The potential for improvement of LAI and LCC was evaluated for both measured data and simulated data. The measured data was collected on 19 July 2016 by a frame-camera mounted on an unmanned aerial vehicle (UAV) over a potato field, where eight experimental plots of 30 × 30 m were designed with different fertilization levels. Dozens of viewing angles, covering the hemisphere up to around 30° from nadir, were obtained by a large forward and sideways overlap of collected images. Simultaneously to the UAV flight, in situ measurements of LAI and LCC were performed. Inversion of the PROSAIL model was done based on nadir data and based on multi-angular data collected by the UAV. Inversion based on the multi-angular data performed slightly better than inversion based on nadir data, indicated by the decrease in RMSE from 0.70 to 0.65 m2/m2 for the estimation of LAI, and from 17.35 to 17.29 μg/cm2 for the estimation of LCC, when nadir data were used and when multi-angular data were used, respectively. In addition to inversions based on measured data, we simulated several datasets at different multi-angular configurations and compared the accuracy of the inversions of these datasets with the inversion based on data simulated at nadir position. In general, the results based on simulated (synthetic) data indicated that when more viewing angles, more well distributed viewing angles, and viewing angles up to larger zenith angles were available for inversion, the most accurate estimations were obtained. Interestingly, when using spectra simulated at multi-angular sampling configurations as

  5. Chlorophyll: The wonder pigment

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.R.

    Chlorophyll, the green plant pigment, a 'real life force' of living beings, besides synthesizing food, is a great source of vitamins, minerals and other phytochemicals. Adding chlorophyll rich food to our diet fortifies our body against health...

  6. Coral lipids and environmental stress.

    Science.gov (United States)

    Harriott, V J

    1993-04-01

    Environmental monitoring of coral reefs is presently limited by difficulties in recognising coral stress, other than by monitoring coral mortality over time. A recent report described an experiment demonstrating that a measured lipid index declined in shaded corals. The technique described might have application in monitoring coral health, with a decline in coral lipid index as an indicator of coral stress. The application of the technique as a practical monitoring tool was tested for two coral species from the Great Barrier Reef. Consistent with the previous results, lipid index for Pocillopora damicornis initially declined over a period of three weeks in corals maintained in filtered seawater in the dark, indicating possible utilization of lipid stored as energy reserves. However, lipid index subsequently rose to near normal levels. In contrast, lipid index of Acropora formosa increased after four weeks in the dark in filtered seawater. The results showed considerable variability in lipid content between samples from the same colony. Results were also found to be dependent on fixation times and sample weight, introducing potential error into the practical application of the technique. The method as described would be unsuitable for monitoring environmental stress in corals, but the search for a practical method to monitor coral health should continue, given its importance in coral reef management.

  7. Zooxanthellar symbiosis in planula larvae of the coral Pocillopora damicornis.

    Science.gov (United States)

    Gaither, Michelle R; Rowan, Rob

    2010-04-30

    We characterized the planular-zooxanthellae symbiosis of the coral Pocillopora damicornis using criteria that are familiar in studies on corals. Similar to adult corals, planulae exhibited photoacclimation, as changes in symbiont chlorophyll a (chl a); changes in the light-saturation constant for photosynthesis (I(k)); and, at insufficient light, fewer zooxanthellae, decreased respiration, increased weight loss, and increased sensitivity to photoinhibition. Numbers of zooxanthellae in newly-released planulae varied by at least three-fold within broods. Planulae with low versus high numbers of zooxanthellae (termed pale versus dark planulae, respectively) did not differ in symbiont chl-a content, I(k), or biomass-specific rate of dark respiration. Pale planulae had lower rates of photosynthesis, but this difference vanished after three weeks, when zooxanthellar numbers increased by 225% in pale planulae and by 31% in dark planulae. Numbers of zooxanthellae also increased significantly in planulae cultured in ammonium-enriched seawater; ammonium also apparently prevented weight loss and induced settlement. Approximately 70% of photosynthetically-fixed carbon (labeled using (14)C) apparently was translocated from the zooxanthellae to their host. A comparison of planulae cultured at 0.3% versus 11% sunlight suggested that photosynthesis provided ~ 31% of the energy utilized by the latter. Overall, we conclude that the physiology of symbiosis in planulae of P. damicornis is broadly similar to symbiosis physiology in adult corals.

  8. Uptake and partitioning of copper and cadmium in the coral Pocillopora damicornis

    International Nuclear Information System (INIS)

    Mitchelmore, Carys L.; Verde, E. Alan; Weis, Virginia M.

    2007-01-01

    Coral-reef ecosystems are increasingly being impacted by a wide variety of anthropogenic inputs, including heavy metals, which could be contributing to coral reef stress and bleaching episodes. Fragments of Pocillopora damicornis were exposed in the laboratory to cadmium (Cd) or copper (Cu) chlorides (0, 5, 50 μg l -1 ) for 14 days and analyzed for metal content in the whole association, algal or animal fractions. Various physiological and biochemical parameters were also measured, such as, algal cell counts, mitotic index, chlorophyll content and levels of the antioxidant glutathione (GSH). Cd and Cu accumulation were observed at all time points and doses; there was no evidence of differential metal partitioning between the algal or animal fractions. No changes in algal cell density, mitotic index or chlorophyll content from the controls were observed in any of the metal treatments. GSH levels were significantly higher in the 5 μg l -1 Cd (Day 4) and Cu (Days 4 and 14) treatments compared with controls at the same time point. Although no evidence of a bleaching response occurred, corals in both 50 μg l -1 metal exposures sloughed off tissues and did not survive the duration of the exposure period. Our results demonstrate the accumulation of Cd and Cu in P. damicornis and mortality in the absence of a bleaching response

  9. Uptake and partitioning of copper and cadmium in the coral Pocillopora damicornis

    Energy Technology Data Exchange (ETDEWEB)

    Mitchelmore, Carys L. [University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 1 Williams Street, P.O. Box 38, Solomons, MD 20688 (United States)], E-mail: Mitchelmore@cbl.umces.edu; Verde, E. Alan [Corning School of Ocean Studies, Maine Maritime Academy, Castine, ME 04420 (United States); Weis, Virginia M. [Department of Zoology, Oregon State University, 3029 Cordley Hall, Corvallis, OR 97331 (United States)

    2007-11-15

    Coral-reef ecosystems are increasingly being impacted by a wide variety of anthropogenic inputs, including heavy metals, which could be contributing to coral reef stress and bleaching episodes. Fragments of Pocillopora damicornis were exposed in the laboratory to cadmium (Cd) or copper (Cu) chlorides (0, 5, 50 {mu}g l{sup -1}) for 14 days and analyzed for metal content in the whole association, algal or animal fractions. Various physiological and biochemical parameters were also measured, such as, algal cell counts, mitotic index, chlorophyll content and levels of the antioxidant glutathione (GSH). Cd and Cu accumulation were observed at all time points and doses; there was no evidence of differential metal partitioning between the algal or animal fractions. No changes in algal cell density, mitotic index or chlorophyll content from the controls were observed in any of the metal treatments. GSH levels were significantly higher in the 5 {mu}g l{sup -1} Cd (Day 4) and Cu (Days 4 and 14) treatments compared with controls at the same time point. Although no evidence of a bleaching response occurred, corals in both 50 {mu}g l{sup -1} metal exposures sloughed off tissues and did not survive the duration of the exposure period. Our results demonstrate the accumulation of Cd and Cu in P. damicornis and mortality in the absence of a bleaching response.

  10. Novel adaptive photosynthetic characteristics of mesophotic symbiotic microalgae within the reef-building coral, Stylophora pistillata

    Directory of Open Access Journals (Sweden)

    Shai Einbinder

    2016-10-01

    Full Text Available Photosynthetic coral reef structures extend from the shallow sundrenched waters to the dimly lit, twilight mesophotic depths. For their resident endosymbiotic dinoflagellates, primarily from the genus Symbiodinium spp., this represents a photic environment that varies ~15 fold in intensity and also differs in spectral composition. We examined photosynthesis in the scleractinian coral Stylophora pistillata in shallow (3 m and mesophotic settings (65m in the northern Red Sea. Symbiodinium spp. in corals originating from the mesophotic environment consistently performed below their photosynthetic compensation point and also exhibited distinct light harvesting antenna organization. In addition, the non-photochemical quenching activity of Symbiodinium spp. from mesophotic corals was shown to be considerably lower than those found in shallow corals, showing they have fewer defenses to high-light settings. Over a period of almost four years, we extensively utilized closed circuit Trimix rebreather diving to perform the study. Phylogenetic analysis showed that shallow corals (3m transplanted to a deep reef environment (65 m maintained their initial Symbiodinium spp. community (clade A, rather than taking on deep low-light clades (clade C, demonstrating that shallow S. pistillata acclimate to low-light mesophotic environments while maintaining their shallow photosynthetic traits. Mesophotic corals exhibited static depth-related chlorophyll content per cell, a decrease in PSI activity and enhanced sigmoidal fluorescence rise kinetics. The sigmoidal fluorescence rise kinetics we observed in mesophotic corals is an indication of energy transfer between photosynthetic units. We postulate that at mesophotic depths, a community of adapted Symbiodinium spp. utilize a unique adaptation to lower light conditions by shifting their light harvesting to a PSII based system, where PSII is structured near PSI, with additional PCP soluble antenna also trapping light

  11. Coral reef health response to chronic and acute changes in water quality in St. Thomas, United States Virgin Islands.

    Science.gov (United States)

    Ennis, Rosmin S; Brandt, Marilyn E; Wilson Grimes, Kristin R; Smith, Tyler B

    2016-10-15

    It is suspected that land cover alteration on the southern coast of St. Thomas, USVI has increased runoff, degrading nearshore water quality and coral reef health. Chronic and acute changes in water quality, sediment deposition, and coral health metrics were assessed in three zones based upon perceived degree of human influence. Chlorophyll (pturbidity (p=0.0113) were significantly higher in nearshore zones and in the high impact zone during heavy precipitation. Net sediment deposition and terrigenous content increased in nearshore zones during periods of greater precipitation and port activity. Macroalgae overgrowth significantly increased along a gradient of decreasing water quality (p<0.0001). Coral bleaching in all zones peaked in November with a regional thermal stress event (p<0.0001). However, mean bleaching prevalence was significantly greater in the most impacted zone compared to the offshore zone (p=0.0396), suggesting a link between declining water quality and bleaching severity. Published by Elsevier Ltd.

  12. Comprehensive chlorophyll composition in the main edible seaweeds.

    Science.gov (United States)

    Chen, Kewei; Ríos, José Julián; Pérez-Gálvez, Antonio; Roca, María

    2017-08-01

    Natural chlorophylls present in seaweeds have been studied regarding their biological activities and health benefit effects. However, detailed studies regarding characterization of the complete chlorophyll profile either qualitatively and quantitatively are scarce. This work deals with the comprehensive spectrometric study of the chlorophyll derivatives present in the five main coloured edible seaweeds. The novel complete MS 2 characterization of five chlorophyll derivatives: chlorophyll c 2 , chlorophyll c 1 , purpurin-18 a, pheophytin d and phytyl-purpurin-18 a has allowed to obtain fragmentation patterns associated with their different structural features. New chlorophyll derivatives have been identified and quantified by first time in red, green and brown seaweeds, including some oxidative structures. Quantitative data of the chlorophyll content comes to achieve significant information for food composition databases in bioactive compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Effect of nitrogen and phosphorus supply on growth, chlorophyll content and tissue composition of the macroalga Chaetomorpha linum (O.F. Müll, Kütz, in a Mediterranean Coastal Lagoon

    Directory of Open Access Journals (Sweden)

    Margarita Menéndez

    2002-12-01

    Full Text Available The effect of dissolved nutrients on growth, nutrient content and uptake rates of Chaetomorpha linum in a Mediterranean coastal lagoon (Tancada, Ebro delta, NE Spain was studied in laboratory experiments. Water was enriched with distinct forms of nitrogen, such as nitrate or ammonium and phosphorus. Enrichment with N, P or with both nutrients resulted in a significant increase in the tissue content of these nutrients. N-enrichment was followed by an increase in chlorophyll content after 4 days of treatment, although the difference was only significant when nitrate was added without P. P-enrichment had no significant effect on chlorophyll content. In all the treatments an increase in biomass was obseved after 10 days. This increase was higher in the N+P treatments. In all the treatments the uptake rate was significantly higher when nutrients were added than in control jars. The uptake rate of N, as ammonium, and P were significantly higher when they were added alone while that of N as nitrate was higher in the N+P treatment. In the P-enriched cultures, the final P-content of macroalgal tissues was ten-fold that of the initial tissue concentrations, thereby indicating luxury P-uptake. Moreover, at the end of the incubation the N:P ratio increased to 80, showing that P rather than N was the limiting factor for C. linum in the Tancada lagoon. The relatively high availability of N is related to the N inputs from rice fields that surround the lagoon and to P binding in sediments.

  14. Teor de clorofila e perfil de sais minerais de Chlorella vulgaris cultivada em solução hidropônica residual Chlorophyll content and minerals profile in the microalgae Chlorella vulgaris cultivated in hydroponic wastewater

    Directory of Open Access Journals (Sweden)

    Fabiano Cleber Bertoldi

    2008-02-01

    Full Text Available O cultivo de microalgas representa uma potencial fonte de biomassa rica em clorofila e sais minerais como: fósforo, ferro, manganês, cobre, zinco, magnésio e cálcio. Este experimento teve como objetivo avaliar a composição de minerais, bem como determinar o teor de clorofila a e b da microalga Chlorella vulgaris cultivada em solução hidropônica residual em três diferentes concentrações comparadas com um cultivo controle. Os resultados mostraram que os teores de clorofila a e b da microalga não apresentaram diferença significativa entre os cultivos. Com relação à composição dos sais minerais, a Chlorella cultivada na solução residual mais concentrada apresentou valores superiores quando comparada com a cultivada nos demais cultivos. Dessa forma, a biomassa da Chlorella vulgaris demonstrou ser uma potencial fonte de clorofila e de sais minerais, quando cultivada em solução hidropônica residual, possibilitando a utilização desse resíduo de forma sustentável.The microalgaes cultive represents a potential source of biomass rich in chlorophyll and minerals as: P, Fe, Mn, Cu, Zn, Mg and Ca. This research was aimed at evaluating the composition of minerals, as well as, determining the content of chlorophyll a and b from the microalgae Chlorella vulgaris cultivated in hydroponic wastewater in three different concentrations compared with the control cultive. The results showed that the contents of chlorophyll a and b of the microalgae did not show significant difference between the cultives. In relation to the composition of the minerals, the Chlorella cultivated in the most concentrated wastewater, showed higher values when compared with the one cultivated in the others cultures. In this manner, the Chlorella vulgaris biomass demonstrated to be a potential source of chlorophyll and minerals, when cultivated in hydroponic wastewater, allowing the use of this residue in a sustainable way.

  15. Chlorophyll b degradation by chlorophyll b reductase under high-light conditions.

    Science.gov (United States)

    Sato, Rei; Ito, Hisashi; Tanaka, Ayumi

    2015-12-01

    The light-harvesting chlorophyll a/b binding protein complex of photosystem II (LHCII) is the main antenna complex of photosystem II (PSII). Plants change their LHCII content depending on the light environment. Under high-light conditions, the content of LHCII should decrease because over-excitation damages the photosystem. Chlorophyll b is indispensable for accumulating LHCII, and chlorophyll b degradation induces LHCII degradation. Chlorophyll b degradation is initiated by chlorophyll b reductase (CBR). In land plants, NON-YELLOW COLORING 1 (NYC1) and NYC1-Like (NOL) are isozymes of CBR. We analyzed these mutants to determine their functions under high-light conditions. During high-light treatment, the chlorophyll a/b ratio was stable in the wild-type (WT) and nol plants, and the LHCII content decreased in WT plants. The chlorophyll a/b ratio decreased in the nyc1 and nyc1/nol plants, and a substantial degree of LHCII was retained in nyc1/nol plants after the high-light treatment. These results demonstrate that NYC1 degrades the chlorophyll b on LHCII under high-light conditions, thus decreasing the LHCII content. After the high-light treatment, the maximum quantum efficiency of the PSII photochemistry was lower in nyc1 and nyc1/nol plants than in WT and nol plants. A larger light-harvesting system would damage PSII in nyc1 and nyc1/nol plants. The fluorescence spectroscopy of the leaves indicated that photosystem I was also damaged by the excess LHCII in nyc1/nol plants. These observations suggest that chlorophyll b degradation by NYC1 is the initial reaction for the optimization of the light-harvesting capacity under high-light conditions.

  16. Evaluation of seven different drying treatments in respect to total flavonoid, phenolic, vitamin C content, chlorophyll, antioxidant activity and color of green tea (Camellia sinensis or C. assamica) leaves.

    Science.gov (United States)

    Roshanak, Sahar; Rahimmalek, Mehdi; Goli, Sayed Amir Hossein

    2016-01-01

    The effect of seven drying treatments (sun, shade, oven 60 °C, oven 80 °C, oven 100 °C, microwave and freeze-drying) were evaluated with respect total flavonoid (TFC), phenolic (TPC), antioxidant activity, vitamin C and color characteristics of green tea. In general, drying increased antioxidant activity, TPC, TFC and chlorophyll content, while it led to a decrease in vitamin C. The highest TPC (209.17 mg Gallic acid/gdw) and TFC (38.18 mg Quercitin/gdw) were obtained in oven drying at 60 and 100 °C, respectively. Among methods, oven drying at 60 °C revealed the highest radical scavenging activity (IC50 = 167.166 μg/ml), while microwave showed the lowest one (IC50 = 505.5 μg/ml). Similar trend was also observed in reducing power assay. The highest vitamin C (16.36 mg/100gDM) and Chlorophyll a (17.35 mg/l) were obtained in freeze drying. Finally, sun and freeze drying methods were considered as the least and the most desirable drying methods, respectively the final color of green tea leaves.

  17. Assimilating solar-induced chlorophyll fluorescence into the terrestrial biosphere model BETHY-SCOPE v1.0: model description and information content

    Science.gov (United States)

    Norton, Alexander J.; Rayner, Peter J.; Koffi, Ernest N.; Scholze, Marko

    2018-04-01

    The synthesis of model and observational information using data assimilation can improve our understanding of the terrestrial carbon cycle, a key component of the Earth's climate-carbon system. Here we provide a data assimilation framework for combining observations of solar-induced chlorophyll fluorescence (SIF) and a process-based model to improve estimates of terrestrial carbon uptake or gross primary production (GPP). We then quantify and assess the constraint SIF provides on the uncertainty in global GPP through model process parameters in an error propagation study. By incorporating 1 year of SIF observations from the GOSAT satellite, we find that the parametric uncertainty in global annual GPP is reduced by 73 % from ±19.0 to ±5.2 Pg C yr-1. This improvement is achieved through strong constraint of leaf growth processes and weak to moderate constraint of physiological parameters. We also find that the inclusion of uncertainty in shortwave down-radiation forcing has a net-zero effect on uncertainty in GPP when incorporated into the SIF assimilation framework. This study demonstrates the powerful capacity of SIF to reduce uncertainties in process-based model estimates of GPP and the potential for improving our predictive capability of this uncertain carbon flux.

  18. Chlorophyll_Master

    Data.gov (United States)

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

  19. OSU Chlorophyll Bloom Product

    Data.gov (United States)

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

  20. The Use of a Chlorophyll Meter (SPAD-502) for Field Determinations of Red Mangrove (Rhizophora Mangle L.) Leaf Chlorophyll Amount

    Science.gov (United States)

    Connelly, Xana M.

    1997-01-01

    The red mangrove Rhizophora mangle L., is a halophytic woody spermatophyte common to the land-sea interface of tropical and subtropical intertidal zones. It has been reported that 60 to 75% of the coastline of the earth's tropical regions are lined with mangroves. Mangroves help prevent shoreline erosion, provide breeding, nesting and feeding areas for many marine animals and birds. Mangroves are important contributors of primary production in the coastal environment, and this is largely proportional to the standing crop of leaf chlorophylls. Higher intensities of ultraviolet radiation, resulting from stratospheric ozone depletion, can lead to a reduction of chlorophyll in terrestrial plants. Since the most common method for determining chlorophyll concentration is by extraction and this is labor intensive and time consuming, few studies on photosynthetic pigments of mangroves have been reported. Chlorophyll meter readings have been related to leaf chlorophyll content in apples and maples. It has also been correlated to nitrogen status in corn and cotton. Peterson et al., (1993) used a chlorophyll meter to detect nitrogen deficiency in crops and in determining the need for additional nitrogen fertilizer. Efforts to correlate chlorophyll meter measurements to chlorophyll content of mangroves have not been reported. This paper describes the use of a hand-held chlorophyll meter (Minolta SPAD-502) to determine the amount of red mangrove foliar chlorophyll present in the field.

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

    Science.gov (United States)

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

    2017-09-01

    In this study, we have compared the photosynthetic characteristics of two contrasting species of Tradescantia plants, T. fluminensis (shade-tolerant species), and T. sillamontana (light-resistant species), grown under the low light (LL, 50-125 µmol photons m -2  s -1 ) or high light (HL, 875-1000 µmol photons m -2  s -1 ) conditions during their entire growth period. For monitoring the functional state of photosynthetic apparatus (PSA), we measured chlorophyll (Chl) a emission fluorescence spectra and kinetics of light-induced changes in the heights of fluorescence peaks at 685 and 740 nm (F 685 and F 740 ). We also compared the light-induced oxidation of P 700 and assayed the composition of carotenoids in Tradescantia leaves grown under the LL and HL conditions. The analyses of slow induction of Chl a fluorescence (SIF) uncovered different traits in the LL- and HL-grown plants of ecologically contrasting Tradescantia species, which may have potential ecophysiological significance with respect to their tolerance to HL stress. The fluorometry and EPR studies of induction events in chloroplasts in situ demonstrated that acclimation of both Tradescantia species to HL conditions promoted faster responses of their PSA as compared to LL-grown plants. Acclimation of both species to HL also caused marked changes in the leaf anatomy and carotenoid composition (an increase in Violaxanthin + Antheraxantin + Zeaxanthin and Lutein pools), suggesting enhanced photoprotective capacity of the carotenoids in the plants grown in nature under high irradiance. Collectively, the results of the present work suggest that the mechanisms of long-term PSA photoprotection in Tradescantia are based predominantly on the light-induced remodeling of pigment-protein complexes in chloroplasts.

  2. The effect of acid rain stress on chlorophyll, peroxidase of the conservation of rare earth elements

    International Nuclear Information System (INIS)

    Chongling, Y.; Yetang, H.; Xianke, Y.; Shunzhen, F.; Shanql, W.

    1998-01-01

    Full text: Based on pot experiment, the effect of acid rain stress on chlorophyll, peroxidase of wheat, the relationship of them and the conservation of rare earth elements has been studied. The result showed: stress of acid rain resulted in decrease of chlorophyll content and a/b values, chlorophyll a/b value and chlorophyll content is positive correlation with pH value of acid rain: peroxidase activity was gradually rise with pH value decrease, which indirectly increased decomposition intensity of chlorophyll. Decreased content and a/b value of chlorophyll further speeded blade decay affected the transport and transformation of light energy and metabolism of carbohydrates. After being treated by rare earth elements content and pH value of chlorophyll and peroxidase activity could be relatively stable. Therefore, under lower acidity condition, rare earth elements can influence the effect of acid rain on chlorophyll and peroxidase activity of wheat

  3. The Impacts of Ex Situ Transplantation on the Physiology of the Taiwanese Reef-Building Coral Seriatopora hystrix

    Directory of Open Access Journals (Sweden)

    Anderson B. Mayfield

    2013-01-01

    Full Text Available We sought to determine whether the Indo-Pacific reef-building coral Seriatopora hystrix performs in a similar manner in the laboratory as it does in situ by measuring Symbiodinium density, chlorophyll a (chl-a concentration, and the maximum quantum yield of photosystem II (FV/FM at the time of field sampling (in situ, as well as after three weeks of acclimation and one week of experimentation (ex situ. Symbiodinium density was similar between corals of the two study sites, Houbihu (an upwelling reef and Houwan (a nonupwelling reef, and also remained at similar levels ex situ as in situ. On the other hand, both areal and cell-specific chl-a concentrations approximately doubled ex situ relative to in situ, an increase that may be due to having employed a light regime that differed from that experienced by these corals on the reefs of southern Taiwan from which they were collected. As this change in Symbiodinium chl-a content was documented in corals of both sites, the experiment itself was not biased by this difference. Furthermore, FV/FM increased by only 1% ex situ relative to in situ, indicating that the corals maintained a similar level of photosynthetic performance as displayed in situ even after one month in captivity.

  4. In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

    Science.gov (United States)

    Jessen, Christian; Villa Lizcano, Javier Felipe; Bayer, Till; Roder, Cornelia; Aranda, Manuel; Wild, Christian; Voolstra, Christian R

    2013-01-01

    Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acropora hemprichii after 1 and 16 weeks of in-situ inorganic nutrient enrichment (via fertilizer diffusion) and/or herbivore exclusion (via caging) in an offshore reef of the Central Red Sea. Simulated eutrophication and/or overfishing treatments did not affect coral physiology with respect to coral respiration rates, chlorophyll a content, zooxanthellae abundance, or δ (15)N isotopic signatures. The bacterial community of A. hemprichii was rich and uneven, and diversity increased over time in all treatments. While distinct bacterial species were identified as a consequence of eutrophication, overfishing, or both, two bacterial species that could be classified to the genus Endozoicomonas were consistently abundant and constituted two thirds of bacteria in the coral. Several nitrogen-fixing and denitrifying bacteria were found in the coral specimens that were exposed to experimentally increased nutrients. However, no particular bacterial species was consistently associated with the coral under a given treatment and the single effects of manipulated eutrophication and overfishing could not predict the combined effect. Our data underlines the importance of conducting field studies in a holobiont framework, taking both, physiological and molecular measures into account.

  5. In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

    Directory of Open Access Journals (Sweden)

    Christian Jessen

    Full Text Available Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acropora hemprichii after 1 and 16 weeks of in-situ inorganic nutrient enrichment (via fertilizer diffusion and/or herbivore exclusion (via caging in an offshore reef of the Central Red Sea. Simulated eutrophication and/or overfishing treatments did not affect coral physiology with respect to coral respiration rates, chlorophyll a content, zooxanthellae abundance, or δ (15N isotopic signatures. The bacterial community of A. hemprichii was rich and uneven, and diversity increased over time in all treatments. While distinct bacterial species were identified as a consequence of eutrophication, overfishing, or both, two bacterial species that could be classified to the genus Endozoicomonas were consistently abundant and constituted two thirds of bacteria in the coral. Several nitrogen-fixing and denitrifying bacteria were found in the coral specimens that were exposed to experimentally increased nutrients. However, no particular bacterial species was consistently associated with the coral under a given treatment and the single effects of manipulated eutrophication and overfishing could not predict the combined effect. Our data underlines the importance of conducting field studies in a holobiont framework, taking both, physiological and molecular measures into account.

  6. In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

    KAUST Repository

    Jessen, Christian

    2013-04-22

    Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acropora hemprichii after 1 and 16 weeks of in-situ inorganic nutrient enrichment (via fertilizer diffusion) and/or herbivore exclusion (via caging) in an offshore reef of the Central Red Sea. Simulated eutrophication and/or overfishing treatments did not affect coral physiology with respect to coral respiration rates, chlorophyll a content, zooxanthellae abundance, or δ (15)N isotopic signatures. The bacterial community of A. hemprichii was rich and uneven, and diversity increased over time in all treatments. While distinct bacterial species were identified as a consequence of eutrophication, overfishing, or both, two bacterial species that could be classified to the genus Endozoicomonas were consistently abundant and constituted two thirds of bacteria in the coral. Several nitrogen-fixing and denitrifying bacteria were found in the coral specimens that were exposed to experimentally increased nutrients. However, no particular bacterial species was consistently associated with the coral under a given treatment and the single effects of manipulated eutrophication and overfishing could not predict the combined effect. Our data underlines the importance of conducting field studies in a holobiont framework, taking both, physiological and molecular measures into account.

  7. Chlorophyll a is a favorable substrate for Chlamydomonas Mg-dechelatase encoded by STAY-GREEN.

    Science.gov (United States)

    Matsuda, Kaori; Shimoda, Yousuke; Tanaka, Ayumi; Ito, Hisashi

    2016-12-01

    Mg removal from chlorophyll by Mg-dechelatase is the first step of chlorophyll degradation. Recent studies showed that in Arabidopsis, Stay Green (SGR) encodes Mg-dechelatase. Though the Escherichia coli expression system is advantageous for investigating the properties of Mg-dechelatase, Arabidopsis Mg-dechelatase is not successfully expressed in E. coli. Chlamydomonas reinhardtii SGR (CrSGR) has a long, hydrophilic tail, suggesting that active CrSGR can be expressed in E. coli. After the incubation of chlorophyll a with CrSGR expressed in E. coli, pheophytin a accumulated, indicating that active CrSGR was expressed in E. coli. Substrate specificity of CrSGR against chlorophyll b and an intermediate molecule of the chlorophyll b degradation pathway was examined. CrSGR exhibited no activity against chlorophyll b and low activity against 7-hydroxymethyl chlorophyll a, consistent with the fact that chlorophyll b is degraded only after conversion to chlorophyll a. CrSGR exhibited low activity against divinyl chlorophyll a and chlorophyll a', and no activity against chlorophyllide a, protochlorophyll a, chlorophyll c 2 , and Zn-chlorophyll a. These observations indicate that chlorophyll a is the most favorable substrate for CrSGR. When CrSGR was expressed in Arabidopsis cells, the chlorophyll content decreased, further confirming that SGR has Mg-dechelating activity in chloroplasts. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  8. SPECTRAL CHARACTERISTICS OF SELECTED HERMATYPIC CORALS FROM GULF OF KACHCHH, INDIA

    Directory of Open Access Journals (Sweden)

    N. Ray Chaudhury

    2012-07-01

    Full Text Available Hermatypic, scleractinian corals are the most important benthic substrates in a coral reef ecosystem. The existing, high (spatial resolution, broad-band, multi-spectral, space-borne sensors have limited capability to spatially detect and spectrally discriminate coral substrates. In situ hyperspectral signatures of eight coral targets were collected with the help of Analytical Spectral Devices FieldSpec spectroradiometer from Paga and Laku Point reefs of Gulf of Kachchh, India to study the spectral behaviour of corals. The eight coral targets consisted of seven live corals representing four distinct colony morphologies and one bleached coral target. The coral spectra were studied over a continuous range of 350 to 1350 nm. The corals strongly reflected in the NIR and MIR regions with regional central maximas located at 820 and 1070 nm respectively. In the visible region the live coral spectra conformed to "brown mode" of coral reflectance with triple-peaked pattern at 575, 600 and 650 nm. All coral spectra are characterized with two distinct absorption features: chlorophyll absorption at 675 nm and water absorption at 975 nm. The live and the bleached corals get distinguished in the visible region over 400 to 600 nm region. Water column over the targets modifies the spectral shape and magnitude. First and second-order derivatives help in identifying spectral windows to distinguish live and bleached corals.

  9. Colony-specific investigations reveal highly variable responses among individual corals to ocean acidification and warming.

    Science.gov (United States)

    Kavousi, Javid; Reimer, James Davis; Tanaka, Yasuaki; Nakamura, Takashi

    2015-08-01

    As anthropogenic climate change is an ongoing concern, scientific investigations on its impacts on coral reefs are increasing. Although impacts of combined ocean acidification (OA) and temperature stress (T) on reef-building scleractinian corals have been studied at the genus, species and population levels, there are little data available on how individual corals respond to combined OA and anomalous temperatures. In this study, we exposed individual colonies of Acropora digitifera, Montipora digitata and Porites cylindrica to four pCO2-temperature treatments including 400 μatm-28 °C, 400 μatm-31 °C, 1000 μatm-28 °C and 1000 μatm-31 °C for 26 days. Physiological parameters including calcification, protein content, maximum photosynthetic efficiency, Symbiodinium density, and chlorophyll content along with Symbiodinium type of each colony were examined. Along with intercolonial responses, responses of individual colonies versus pooled data to the treatments were investigated. The main results were: 1) responses to either OA or T or their combination were different between individual colonies when considering physiological functions; 2) tolerance to either OA or T was not synonymous with tolerance to the other parameter; 3) tolerance to both OA and T did not necessarily lead to tolerance of OA and T combined (OAT) at the same time; 4) OAT had negative, positive or no impacts on physiological functions of coral colonies; and 5) pooled data were not representative of responses of all individual colonies. Indeed, the pooled data obscured actual responses of individual colonies or presented a response that was not observed in any individual. From the results of this study we recommend improving experimental designs of studies investigating physiological responses of corals to climate change by complementing them with colony-specific examinations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Chlorophyll formation and phytochrome

    NARCIS (Netherlands)

    Raven, C.W.

    1973-01-01

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

  11. Reef corals bleach to resist stress.

    Science.gov (United States)

    Obura, David O

    2009-02-01

    A rationale is presented here for a primary role of bleaching in regulation of the coral-zooxanthellae symbiosis under conditions of stress. Corals and zooxanthellae have fundamentally different metabolic rates, requiring active homeostasis to limit zooxanthellae production and manage translocated products to maintain the symbiosis. The control processes for homeostasis are compromised by environmental stress, resulting in metabolic imbalance between the symbionts. For the coral-zooxanthella symbiosis the most direct way to minimize metabolic imbalance under stress is to reduce photosynthetic production by zooxanthellae. Two mechanisms have been demonstrated that do this: reduction of the chlorophyll concentration in individual zooxanthellae and reduction of the relative biomass of zooxanthellae. Both mechanisms result in visual whitening of the coral, termed bleaching. Arguments are presented here that bleaching provides the final control to minimize physiological damage from stress as an adversity response to metabolic imbalance. As such, bleaching meets the requirements of a stress response syndrome/general adaptive mechanism that is sensitive to internal states rather than external parameters. Variation in bleaching responses among holobionts reflects genotypic and phenotypic differentiation, allowing evolutionary change by natural selection. Thus, reef corals bleach to resist stress, and thereby have some capacity to adapt to and survive change. The extreme thermal anomalies causing mass coral bleaching worldwide lie outside the reaction norms for most coral-zooxanthellae holobionts, revealing the limitations of bleaching as a control mechanism.

  12. Salinity reduced growth PS2 photochemistry and chlorophyll content in radish Crescimento reduzido por salinidade, fotoquímica PS2 e conteúdo de clorofila em rabanete

    Directory of Open Access Journals (Sweden)

    Muhammad Jamil

    2007-01-01

    Full Text Available When plants are grown under saline conditions, photosynthetic activity decreases leading to reduced plant growth, leaf area, chlorophyll content and chlorophyll fluorescence. Seeds and seedlings of radish (Raphanus sativus L. were grown in NaCl solutions under controlled greenhouse conditions. The NaCl concentrations in complete nutrient solutions were 0 (control, 4.7, 9.4 and 14.1 dS m-1. The salinity reduced germination percentage and also delayed the germination rate as the salt level increased. Lengths and fresh weights of root and shoot decreased with the increasing salt concentration. Furthermore, photochemical efficiency of PS2 (Fv/Fm, photochemical quenching coefficient (qP, non photochemical quenching coefficient (qN, leaf area and chlorophyll content (SPAD value were also reduced (P Quando plantas crescem sob condições de salinidade, sua atividade fotossintética diminui levando a um crescimento reduzido, menor área foliar, conteúdo de clorofila e fluorescência de clorofila. Sementes e plântulas de rabanete (Raphanus sativus L. foram germinadas e conduzidas em soluções de NaCl sob condições controladas de casa de vegetação. As concentrações de NaCl adicionado a solução nutritiva completa foram 0 (Controle, 4,7; 9,4 e 14,1 dS m-1. A salinidade diminui a percentagem de germinação e também atrasou a taxa de germinação com o aumento do nível de sal. Comprimento e peso fresco da parte aérea e da raiz decresceram com o aumento da concentração salina. Além disso, a eficiência fotoquímica de PS2 (Fv/Fm, o coeficiente fotoquímico de 'quenchin" (q p, o coeficiente não fotoquímico de "quenching" (q n, a área foliar e o teor de clorofila (valor SPAD também foram reduzidos (P < 0,001 por estresse de sal. Ao contrário, a relação Fo/Fm aumentou com a concentração salina, ao passo que a salinidade não teve efeito sobre a eficiência de excitação capturada pelo PS2 aberto (Fv'/Fm', taxa de transporte eletr

  13. Effects of copper stress on antioxidative enzymes, chlorophyll and ...

    African Journals Online (AJOL)

    Effects of copper stress on antioxidative enzymes, chlorophyll and protein content in Atriplex ... Journal Home > Vol 10, No 50 (2011) > ... The aim of this work was to investigate some enzymatic systems response of this plant to copper stress.

  14. Crowning corals

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.

    and build-awareness about the rich, diverse biological resources is warranted and a plea is made to manage the sewage, oil and thermal pollution to help preserve the biodiversity of coral and associated flora and fauna....

  15. Pulse amplitude modulated chlorophyll fluorometer

    Science.gov (United States)

    Greenbaum, Elias; Wu, Jie

    2015-12-29

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

  16. Liquid scintillation counting of chlorophyll

    International Nuclear Information System (INIS)

    Fric, F.; Horickova, B.; Haspel-Horvatovic, E.

    1975-01-01

    A precise and reproducible method of liquid scintillation counting was worked out for measuring the radioactivity of 14 C-labelled chlorophyll a and chlorophyll b solutions without previous bleaching. The spurious count rate caused by luminescence of the scintillant-chlorophyll system is eliminated by using a suitable scintillant and by measuring the radioactivity at 4 to 8 0 C after an appropriate time of dark adaptation. Bleaching of the chlorophyll solutions is necessary only for measuring of very low radioactivity. (author)

  17. [Light absorption by carotenoid peridinin in zooxanthellae cell and setting down of hermatypic coral to depth].

    Science.gov (United States)

    Leletkin, V A; Popova, L I

    2005-01-01

    Carotenoid peridinin absorbs ocean light which could penetrate deep into the water. Absolute and relative contents of symbiotic dinoflagellatae zooxanthellae are increased with depth of habitat of germatypic corals. To estimate whether the presence of peridinin in corals is chromatic adaptation or not, the absorbance of solar radiation by different amounts of peridinin and chlorophyll in natice zooxanthellae cells was evaluated. Calculations have shown that at the great depths the peredinin absorbance corresponds to 42% of total cell absorbance and that the increase of light absorbance correlating with changes of its spectral characteristics is entirely determined by presence of this carotenoid. The increase of amount of peridinin in cell is as much important as important the increase of all other pigments taken together. However, at the same time selective and preferential accumulation of peridinin and the change of its native state in the limits naturally occurred in zooxanthellae cells have only low impact on the light absorbance. The presence of peridinin could be considered as manifestation of chromatic adaptation of organism. The comparison of light absorption by zooxanthellae with different content of peridinin (or without peridinin) reveals that this pigment expands the habitat of hermatypic corals in ocean waters at 8-17 meters into the deep.

  18. Water column productivity and temperature predict coral reef regeneration across the Indo-Pacific

    Science.gov (United States)

    Riegl, B.; Glynn, P. W.; Wieters, E.; Purkis, S.; D'Angelo, C.; Wiedenmann, J.

    2015-02-01

    Predicted increases in seawater temperatures accelerate coral reef decline due to mortality by heat-driven coral bleaching. Alteration of the natural nutrient environment of reef corals reduces tolerance of corals to heat and light stress and thus will exacerbate impacts of global warming on reefs. Still, many reefs demonstrate remarkable regeneration from past stress events. This paper investigates the effects of sea surface temperature (SST) and water column productivity on recovery of coral reefs. In 71 Indo-Pacific sites, coral cover changes over the past 1-3 decades correlated negative-exponentially with mean SST, chlorophyll a, and SST rise. At six monitoring sites (Persian/Arabian Gulf, Red Sea, northern and southern Galápagos, Easter Island, Panama), over half of all corals were coral reefs presently have the best chances for survival. However, reefs best buffered against temperature and nutrient effects are those that current studies suggest to be most at peril from future ocean acidification.

  19. Revisiting chlorophyll extraction methods in biological soil crusts - methodology for determination of chlorophyll a and chlorophyll a + b as compared to previous methods

    Science.gov (United States)

    Caesar, Jennifer; Tamm, Alexandra; Ruckteschler, Nina; Lena Leifke, Anna; Weber, Bettina

    2018-03-01

    Chlorophyll concentrations of biological soil crust (biocrust) samples are commonly determined to quantify the relevance of photosynthetically active organisms within these surface soil communities. Whereas chlorophyll extraction methods for freshwater algae and leaf tissues of vascular plants are well established, there is still some uncertainty regarding the optimal extraction method for biocrusts, where organism composition is highly variable and samples comprise major amounts of soil. In this study we analyzed the efficiency of two different chlorophyll extraction solvents, the effect of grinding the soil samples prior to the extraction procedure, and the impact of shaking as an intermediate step during extraction. The analyses were conducted on four different types of biocrusts. Our results show that for all biocrust types chlorophyll contents obtained with ethanol were significantly lower than those obtained using dimethyl sulfoxide (DMSO) as a solvent. Grinding of biocrust samples prior to analysis caused a highly significant decrease in chlorophyll content for green algal lichen- and cyanolichen-dominated biocrusts, and a tendency towards lower values for moss- and algae-dominated biocrusts. Shaking of the samples after each extraction step had a significant positive effect on the chlorophyll content of green algal lichen- and cyanolichen-dominated biocrusts. Based on our results we confirm a DMSO-based chlorophyll extraction method without grinding pretreatment and suggest the addition of an intermediate shaking step for complete chlorophyll extraction (see Supplement S6 for detailed manual). Determination of a universal chlorophyll extraction method for biocrusts is essential for the inter-comparability of publications conducted across all continents.

  20. Revisiting chlorophyll extraction methods in biological soil crusts – methodology for determination of chlorophyll a and chlorophyll a + b as compared to previous methods

    Directory of Open Access Journals (Sweden)

    J. Caesar

    2018-03-01

    Full Text Available Chlorophyll concentrations of biological soil crust (biocrust samples are commonly determined to quantify the relevance of photosynthetically active organisms within these surface soil communities. Whereas chlorophyll extraction methods for freshwater algae and leaf tissues of vascular plants are well established, there is still some uncertainty regarding the optimal extraction method for biocrusts, where organism composition is highly variable and samples comprise major amounts of soil. In this study we analyzed the efficiency of two different chlorophyll extraction solvents, the effect of grinding the soil samples prior to the extraction procedure, and the impact of shaking as an intermediate step during extraction. The analyses were conducted on four different types of biocrusts. Our results show that for all biocrust types chlorophyll contents obtained with ethanol were significantly lower than those obtained using dimethyl sulfoxide (DMSO as a solvent. Grinding of biocrust samples prior to analysis caused a highly significant decrease in chlorophyll content for green algal lichen- and cyanolichen-dominated biocrusts, and a tendency towards lower values for moss- and algae-dominated biocrusts. Shaking of the samples after each extraction step had a significant positive effect on the chlorophyll content of green algal lichen- and cyanolichen-dominated biocrusts. Based on our results we confirm a DMSO-based chlorophyll extraction method without grinding pretreatment and suggest the addition of an intermediate shaking step for complete chlorophyll extraction (see Supplement S6 for detailed manual. Determination of a universal chlorophyll extraction method for biocrusts is essential for the inter-comparability of publications conducted across all continents.

  1. Chlorophyll loss associated with heat-induced senescence in bentgrass.

    Science.gov (United States)

    Jespersen, David; Zhang, Jing; Huang, Bingru

    2016-08-01

    Heat stress-induced leaf senescence is characterized by the loss of chlorophyll from leaf tissues. The objectives of this study were to examine genetic variations in the level of heat-induced leaf senescence in hybrids of colonial (Agrostis capillaris)×creeping bentgrass (Agrostis stolonifera) contrasting in heat tolerance, and determine whether loss of leaf chlorophyll during heat-induced leaf senescence was due to suppressed chlorophyll synthesis and/or accelerated chlorophyll degradation in the cool-season perennial grass species. Plants of two hybrid backcross genotypes ('ColxCB169' and 'ColxCB190') were exposed to heat stress (38/33°C, day/night) for 28 d in growth chambers. The analysis of turf quality, membrane stability, photochemical efficiency, and chlorophyll content demonstrated significant variations in the level of leaf senescence induced by heat stress between the two genotypes, with ColXCB169 exhibiting a lesser degree of decline in chlorophyll content, photochemical efficiency and membrane stability than ColXCB190. The assays of enzymatic activity or gene expression of several major chlorophyll-synthesizing (porphobilinogen deaminase, Mg-chelatase, protochlorophyllide-reductase) and chlorophyll-degrading enzymes (chlorophyllase, pheophytinase, and chlorophyll-degrading peroxidase) indicated heat-induced decline in leaf chlorophyll content was mainly due to accelerated chlorophyll degradation, as manifested by increased gene expression levels of chlorophyllase and pheophytinase, and the activity of pheophytinase (PPH), while chlorophyll-synthesizing genes and enzymatic activities were not differentially altered by heat stress in the two genotypes. The analysis of heat-induced leaf senescence of pph mutants of Arabidopsis further confirmed that PPH could be one enzymes that plays key roles in regulating heat-accelerated chlorophyll degradation. Further research on enzymes responsible in part for the loss of chlorophyll during heat

  2. Substratum as a driver of variation in periphyton chlorophyll and productivity in lakes

    DEFF Research Database (Denmark)

    Vadeboncoeur, Y.; Kalff, J.; Christoffersen, Kirsten Seestern

    2006-01-01

    content of periphyton on hard substrata (rocks and wood) was positively related to water-column total P (TP), whereas chlorophyll content of algae on sediment (epipelon) and TP were not significantly related. Chlorophyll content was up to 100× higher on sediments than on hard substrata. Within regions...... of the littoral zones in nutrient and energy cycles in lakes....

  3. Quantificação da área e do teor de clorofilas em folhas de plantas jovens de videira 'Cabernet Sauvignon' mediante métodos não destrutivos Non-destructive quantification of area and chlorophyll content in the leaves of young 'Cabernet Sauvignon' grapevines

    Directory of Open Access Journals (Sweden)

    Cassandro Vidal Talamini do Amarante

    2009-09-01

    Full Text Available Este trabalho foi conduzido visando a desenvolver métodos não destrutivos para estimar a área foliar e o conteúdo de clorofilas em folhas de plantas jovens de videira 'Cabernet Sauvignon'. Para a estimativa da área foliar, foram tomadas medidas de comprimento da nervura principal e das duas maiores nervuras secundárias em folhas representando uma grande amplitude de áreas foliares, seguindo-se da leitura em um integrador de área foliar. Para a quantificação de clorofilas, folhas com tonalidades variando de verde-amareladas (folha clorótica a verde-escuras foram avaliadas individualmente com um medidor de clorofila (Minolta SPAD-502 e um colorímetro (Minolta CR-400, no espaço de cores L, C e hº, nas faces abaxial (inferior e adaxial (superior, seguido de quantificações destrutivas de clorofilas a, b e totais. A quantificação do comprimento da nervura principal proporcionou boa estimativa da área foliar, sendo que a soma do comprimento das duas nervuras secundárias, bem como do somatório destes comprimentos com o comprimento da nervura principal, resultou em aumento muito pequeno na capacidade de estimativa da área foliar. Os valores das leituras do medidor de clorofila e da relação hº/(LxC do colorímetro, avaliados em ambas as faces das folhas, aumentaram com o incremento nos teores de clorofilas. Os modelos ajustados entre os teores de clorofilas e as leituras do medidor de clorofila e da relação hº/(LxC do colorímetro apresentaram valores de R² similares. Todavia, a medição da relação hº/(LxC do colorímetro, feita na face adaxial da folha, mostrou melhor estimativa do teor de clorofila, expresso em unidade de área (µg.cm-2 de folha.This work was carried out to develop non destructive methods to estimate the area and chlorophylls content in the leaves of young grapevines 'Cabernet Sauvignon'. For leaf area estimation, the lengths of main and two secondary leaf veins were measured, in leaves ranging from

  4. Population density and photosynthetic pigment content in symbiotic dinoflagellates in the Brazilian scleractinian coral Montastrea cavernosa (Linnaeus, 1767

    Directory of Open Access Journals (Sweden)

    Cristiane F. Costa

    2004-06-01

    Full Text Available The seasonal dynamics of cell density and photosynthetic pigment contents of the zooxanthellae hosted by Montastrea cavernosa were investigated on coastal reefs off Picãozinho (06º42'05"/07º07'30"S and 34º48'37"/34º50'00" W, Northeast Brazil between September 1999 and 2000. A distinct pattern of these parameters was found: cell numbers were greater during the rainy season (autumn/winter while photosynthetic pigments were greater during the dry season (summer. Both parameters showed drastic reductions during heavy rains (June and July 1999. We speculate that this pattern is largely influenced by the rain cycles which, owing to their magnitude and frequency, affect the water clarity and the seasonal physiological condition of the cells.A dinâmica sazonal na densidade de células e na concentração de pigmentos fotossintetizantes das zooxantelas de Montastrea cavernosa foram analisados no período setembro/1999 a setembro/2000 nos Recifes do Picãozinho (06º42'05"/07º07'30" S e 34º48'37"/34º50'00" W, Nordeste do Brasil. Verificou-se que existe um padrão distinto entre estes parâmetros, com maior quantidade de células no período chuvoso e maior concentração de pigmentos fotossintetizantes na época de estiagem. Ambos os parâmetros apresentaram, no entanto, uma nítida redução em seus valores nos meses de maiores índices pluviométricos (junho e julho /1999. Especulamos que tal fato deve estar relacionado com o regime de chuvas que pode variar em magnitude e freqüência, afetando a qualidade ótica da água e o estado fisiológico das células.

  5. Using EO-1 Hyperion to Simulate HyspIRI Products for a Coniferous Forest: The Fraction of PAR Absorbed by Chlorophyll (fAPAR(sub chl)) and Leaf Water Content(LWC)

    Science.gov (United States)

    Zhang, Qingyuan; Middleton, Elizabeth M.; Gao, Bo-Cai; Cheng, Yen-Ben

    2012-01-01

    This paper presents development of prototype products for terrestrial ecosystems in preparation for the future imaging spectrometer planned for the Hyperspectral Infrared Imager (HyspIRI) mission. We present a successful demonstration example in a coniferous forest of two product prototypes: fraction of photosynthetically active radiation (PAR) absorbed by chlorophyll of a canopy (fAPARchl) and leaf water content (LWC), for future HyspIRI implementation at 60-m spatial resolution. For this, we used existing 30-m resolution imaging spectrometer data available from the Earth Observing One (EO-1) Hyperion satellite to simulate and prototype the level one radiometrically corrected radiance (L1R) images expected from the HyspIRI visible through shortwave infrared spectrometer. The HyspIRIlike images were atmospherically corrected to obtain surface reflectance and spectrally resampled to produce 60-m reflectance images for wavelength regions that were comparable to all seven of the MODerate resolution Imaging Spectroradiometer (MODIS) land bands. Thus, we developed MODIS-like surface reflectance in seven spectral bands at the HyspIRI-like spatial scale, which was utilized to derive fAPARchl and LWC with a coupled canopy-leaf radiative transfer model (PROSAIL2) for the coniferous forest. With this paper, we provide additional evidence that the fAPARchl product is more realistic in describing the physiologically active canopy than the traditional fAPAR parameter for the whole canopy (fAPARcanopy), and thus, it should replace it in ecosystem process models to reduce uncertainties in terrestrial carbon cycle and ecosystem studies.

  6. The Effect of Supplemental Irrigation on Canopy Temperature Depression, Chlorophyll Content, and Water Use Efficiency in Three Wheat (Triticum aestivum L. and T. durum Desf. Varieties Grown in Dry Regions of Jordan

    Directory of Open Access Journals (Sweden)

    Abdul Latief A. Al-Ghzawi

    2018-05-01

    Full Text Available One critical challenge facing the world is the need to satisfy the food requirements of the dramatically growing population. Drought stress is one of the main limiting factors in the wheat-producing regions; therefore, wheat yield stability is a major objective of wheat-breeding programs in Jordan, which experience fluctuating climatic conditions in the context of global climate change. In the current study, a two-year field experiment was conducted for exploring the effect of four different water regimes on the yield, yield components, and stability of three wheat (Triticum aestivum L.; T. durum Desf. Jordanian cultivars as related to Canopy Temperature Depression (CTD, and Chlorophyll Content (measured by Soil-Plant Analysis Development, SPAD. A split plot design was used in this experiment with four replicates. Water treatment was applied as the main factor: with and without supplemental irrigation; 0%, 50%, 75%, and 100% of field capacity were applied. Two durum wheat cultivars and one bread wheat cultivar were split over irrigation treatments as a sub factor. In both growing seasons, supplemental irrigation showed a significant increase in grain yield compared to the rain-fed conditions. This increase in grain yield was due to the significantly positive effect of water availability on yield components. Values of CTD, SPAD, harvest index, and water use efficiency (WUE were increased significantly with an increase in soil moisture and highly correlated with grain yield. Ammon variety produced the highest grain yield across the four water regimes used in this study. This variety was characterized by the least thermal time to maturity and the highest values of CTD and SPAD. It was concluded that Ammon had the highest stability among the cultivars tested. Furthermore, CTD and SPAD can be used as important selection parameters in breeding programs in Jordan to assist in developing high-yielding genotypes under drought and heat stress conditions.

  7. Using EO-1 Hyperion to Simulate HyspIRI Products for a Coniferous Forest: The Fraction of PAR Absorbed by Chlorophyll (fAPAR(sub chl)) and Leaf Water Content (LWC)

    Science.gov (United States)

    Zhang, Qingyuan; Middleton, Elizabeth M.; Gao, Bo-Cai; Cheng, Yen-Ben

    2011-01-01

    This study presents development of prototype products for terrestrial ecosystems in preparation for the future imaging spectrometer planned for the Hyperspectral Infrared Imager (HyspIRI) mission. We present a successful demonstration example in a coniferous forest of two product prototypes: fraction of photosynthetic active radiation (PAR) absorbed by chlorophyll of a canopy (fAPAR(sub chl)) and leaf water content (LWC), for future HyspIRI implementation at 60 m spatial resolution. For this, we used existing 30 m resolution imaging spectrometer data available from the Earth Observing One (EO-1) Hyperion satellite to simulate and prototype the level one radiometrically corrected radiance (L1R) images expected from the HyspIRI visible through shortwave infrared spectrometer. The HyspIRI-like images were atmospherically corrected to obtain surface reflectance, and spectrally resampled to produce 60 m reflectance images for wavelength regions that were comparable to all seven of the MODerate resolution Imaging Spectroradiometer (MODIS) land bands. Thus, we developed MODIS-like surface reflectance in seven spectral bands at the HyspIRI-like spatial scale, which was utilized to derive fAPARchl and LWC with a coupled canopy-leaf radiative transfer model (PROSAIL2) for the coniferous forest[1]. With this study, we provide additional evidence that the fAPARchl product is more realistic for describing the physiologically active canopy than the traditional fAPAR parameter for the whole canopy (fAPAR(sub canopy)), and thus should replace it in ecosystem process models to reduce uncertainties in terrestrial carbon cycle studies and ecosystem studies.

  8. Fast growth may impair regeneration capacity in the branching coral Acropora muricata.

    Science.gov (United States)

    Denis, Vianney; Guillaume, Mireille M M; Goutx, Madeleine; de Palmas, Stéphane; Debreuil, Julien; Baker, Andrew C; Boonstra, Roxane K; Bruggemann, J Henrich

    2013-01-01

    Regeneration of artificially induced lesions was monitored in nubbins of the branching coral Acropora muricata at two reef-flat sites representing contrasting environments at Réunion Island (21°07'S, 55°32'E). Growth of these injured nubbins was examined in parallel, and compared to controls. Biochemical compositions of the holobiont and the zooxanthellae density were determined at the onset of the experiment, and the photosynthetic efficiency (Fv/Fm ) of zooxanthellae was monitored during the experiment. Acropora muricata rapidly regenerated small lesions, but regeneration rates significantly differed between sites. At the sheltered site characterized by high temperatures, temperature variations, and irradiance levels, regeneration took 192 days on average. At the exposed site, characterized by steadier temperatures and lower irradiation, nubbins demonstrated fast lesion repair (81 days), slower growth, lower zooxanthellae density, chlorophyll a concentration and lipid content than at the former site. A trade-off between growth and regeneration rates was evident here. High growth rates seem to impair regeneration capacity. We show that environmental conditions conducive to high zooxanthellae densities in corals are related to fast skeletal growth but also to reduced lesion regeneration rates. We hypothesize that a lowered regenerative capacity may be related to limited availability of energetic and cellular resources, consequences of coral holobionts operating at high levels of photosynthesis and associated growth.

  9. Fast growth may impair regeneration capacity in the branching coral Acropora muricata.

    Directory of Open Access Journals (Sweden)

    Vianney Denis

    Full Text Available Regeneration of artificially induced lesions was monitored in nubbins of the branching coral Acropora muricata at two reef-flat sites representing contrasting environments at Réunion Island (21°07'S, 55°32'E. Growth of these injured nubbins was examined in parallel, and compared to controls. Biochemical compositions of the holobiont and the zooxanthellae density were determined at the onset of the experiment, and the photosynthetic efficiency (Fv/Fm of zooxanthellae was monitored during the experiment. Acropora muricata rapidly regenerated small lesions, but regeneration rates significantly differed between sites. At the sheltered site characterized by high temperatures, temperature variations, and irradiance levels, regeneration took 192 days on average. At the exposed site, characterized by steadier temperatures and lower irradiation, nubbins demonstrated fast lesion repair (81 days, slower growth, lower zooxanthellae density, chlorophyll a concentration and lipid content than at the former site. A trade-off between growth and regeneration rates was evident here. High growth rates seem to impair regeneration capacity. We show that environmental conditions conducive to high zooxanthellae densities in corals are related to fast skeletal growth but also to reduced lesion regeneration rates. We hypothesize that a lowered regenerative capacity may be related to limited availability of energetic and cellular resources, consequences of coral holobionts operating at high levels of photosynthesis and associated growth.

  10. Discordant coral-symbiont structuring: factors shaping geographical variation of Symbiodinium communities in a facultative zooxanthellate coral genus, Oculina

    Science.gov (United States)

    Leydet, Karine Posbic; Hellberg, Michael E.

    2016-06-01

    Understanding the factors that help shape the association between corals and their algal symbionts, zooxanthellae ( Symbiodinium), is necessary to better understand the functional diversity and acclimatization potential of the coral host. However, most studies focus on tropical zooxanthellate corals and their obligate algal symbionts, thus limiting our full comprehension of coral-algal symbiont associations. Here, we examine algal associations in a facultative zooxanthellate coral. We survey the Symbiodinium communities associated with Oculina corals in the western North Atlantic and the Mediterranean using one clade-level marker ( psbA coding region) and three fine-scale markers ( cp23S- rDNA, b7sym15 flanking region, and b2sym17). We ask whether Oculina spp. harbor geographically different Symbiodinium communities across their geographic range and, if so, whether the host's genetics or habitat differences are correlated with this geographical variation. We found that Oculina corals harbor different Symbiodinium communities across their geographical range. Of the habitat differences (including chlorophyll a concentration and depth), sea surface temperature is better correlated with this geographical variation than the host's genetics, a pattern most evident in the Mediterranean. Our results suggest that although facultative zooxanthellate corals may be less dependent on their algal partners compared to obligate zooxanthellate corals, the Symbiodinium communities that they harbor may nevertheless reflect acclimatization to environmental variation among habitats.

  11. Evaluation of nitrogen status and total chlorophyll in longkong (Aglaia dookkoo Griff. leaves under water stress using a chlorophyll meter

    Directory of Open Access Journals (Sweden)

    Sdoodee, S.

    2005-07-01

    Full Text Available A chlorophyll meter (SPAD-502 was used to assess nitrogen status and total chlorophyll in longkong leaves, leaves from twelve of 10-year-old trees grown in the experimental plot at Prince of Songkla University, Songkhla province. The relationship between SPAD-502 meter reading and nitrogen status and total chlorophyll content analyzed in the laboratory was evaluated during 8 months (May-December 2003. It was found that the trend of the relationships in each month was similar. There was no significant differenceamong regression linears of all months. The data of 8 months showed that SPAD-reading and nitrogen content, and SPAD-reading and total chlorophyll content were related in a positive manner. They were Y = 0.19X+10.10, r = 0.76** (n = 240, and Y = 0.43X-7.89, r = 0.79** (n = 400, respectively. The SPAD-502 was then used to assess total nitrogen and total chlorophyll content during imposed water stress. Fifteen 4-yearold plants were grown in pots (each pot containing 50 kg soil volume. The experiment was arranged in acompletely randomized design with 3 treatments: (1 daily watering (2 once watering on day 7 (3 no watering with 5 replications during 14 days of the experimental period. Measurements showed a continuous decrease of SPAD-reading in the treatment of no watering. On day 14, a significant difference of SPAD- reading values between the treatment of daily watering and no watering was found. Then, the values of nitrogen content and total chlorophyll were assessed by using the linear regression equations. From the result, it is suggested that the measurement by chlorophyll meter is a rapid technique for the evaluation of total chlorophyll and nitrogen status in longkong leaves during water stress.

  12. Chlorophyllase in Piper betle L. has a role in chlorophyll homeostasis and senescence dependent chlorophyll breakdown.

    Science.gov (United States)

    Gupta, Supriya; Gupta, Sanjay Mohan; Sane, Aniruddha P; Kumar, Nikhil

    2012-06-01

    Total chlorophyll content and chlorophyllase (chlorophyll-chlorophyllido hydrolase EC 3.1.1.14) activity in fresh leaves of Piper betle L. landrace KS was, respectively, twofold higher and eight fold lower than KV, showing negative correlation between chlorophyll and chlorophyllase activity. Specific chlorophyllase activity was nearly eightfold more in KV than KS. ORF of 918 nt was found in cloned putative chlorophyllase cDNAs from KV and KS. The gene was present as single copy in both the landraces. The encoded polypeptide of 306 amino acids differed only at two positions between the KV and KS; 203 (cysteine to tyrosine) and 301 (glutamine to glycine). Difference in chlorophyllase gene expression between KV and KS was evident in fresh and excised leaves. Up regulation of chlorophyllase gene by ABA and down regulation by BAP was observed in both the landraces; however, there was quantitative difference between KV and KS. Data suggests that chlorophyllase in P. betle is involved in chlorophyll homeostasis and chlorophyll loss during post harvest senescence.

  13. Nutritional status and metabolism of the coral Stylophora subseriata along a eutrophication gradient in Spermonde Archipelago (Indonesia)

    Science.gov (United States)

    Sawall, Y.; Teichberg, M. C.; Seemann, J.; Litaay, M.; Jompa, J.; Richter, C.

    2011-09-01

    Coral responses to degrading water quality are highly variable between species and depend on their trophic plasticity, acclimatization potential, and stress resistance. To assess the nutritional status and metabolism of the common scleractinian coral, Stylophora subseriata, in situ experiments were carried along a eutrophication gradient in Spermonde Archipelago, Indonesia. Coral fragments were incubated in light and dark chambers to measure photosynthesis, respiration, and calcification in a number of shallow reefs along the gradient. Chlorophyll a (chl a), protein content, maximum quantum yield ( F v/ F m), and effective quantum yield (Φ PS II) were measured on the zooxanthellae, in addition to host tissue protein content and biomass. Photosynthetic rates were 2.5-fold higher near-shore than mid-shelf due to higher areal zooxanthellae and chl a concentrations and a higher photochemical efficiency (Φ PS II). A 2- and 3-fold increase in areal host tissue protein and biomass was found, indicating a higher nutritional supply in coastal waters. Dark respiration, however, showed no corresponding changes. There was a weak correlation between calcification and photosynthesis (Pearson r = 0.386) and a lack of metabolic stress, as indicated by constant respiration and F v/ F m and the "clean" and healthy appearance of the colonies in spite of high turbidity in near-shore waters. The latter suggests that part of the energetic gains through increased auto- and heterotrophy were spent on metabolic expenditures, e.g., mucus production. While coastal pollution is always deleterious to the reef ecosystem as a whole, our results show that the effect on corals may not always be negative. Thus, S. subseriata may be one of the few examples of corals actually profiting from land-based sources of pollution.

  14. Ontogenetic dietary changes of coral reef fishes in the mangrove-seagress-reef continuum: stable isotope and gut-content analysis

    NARCIS (Netherlands)

    Cocheret de la Morinière, E.; Pollux, B.J.A.; Nagelkerken, I.; Hemminga, M.A.; Huiskes, A.H.L.; Van der Velde, G.

    2003-01-01

    Juveniles of a number of reef fish species develop in shallow-water 'nursery' habitats such as mangroves and seagrass beds, and then migrate to the coral reef. This implies that some reef fish species are distributed over the mangrove-seagrass-reef continuum in subpopulations with different size

  15. Quantifying climatological ranges and anomalies for Pacific coral reef ecosystems.

    Science.gov (United States)

    Gove, Jamison M; Williams, Gareth J; McManus, Margaret A; Heron, Scott F; Sandin, Stuart A; Vetter, Oliver J; Foley, David G

    2013-01-01

    Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic-biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will help

  16. Quantifying Climatological Ranges and Anomalies for Pacific Coral Reef Ecosystems

    Science.gov (United States)

    Gove, Jamison M.; Williams, Gareth J.; McManus, Margaret A.; Heron, Scott F.; Sandin, Stuart A.; Vetter, Oliver J.; Foley, David G.

    2013-01-01

    Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic–biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will

  17. Quantifying climatological ranges and anomalies for Pacific coral reef ecosystems.

    Directory of Open Access Journals (Sweden)

    Jamison M Gove

    Full Text Available Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic-biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km from 85% of our study locations

  18. LAI and chlorophyll estimation for a heterogeneous grassland using hyperspectral measurements

    NARCIS (Netherlands)

    Darvishzadeh, R.; Skidmore, A.K.; Schlerf, M.; Atzberger, C.; Corsi, F.; Cho, M.A.

    2008-01-01

    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

  19. Chlorophyll d: the puzzle resolved

    DEFF Research Database (Denmark)

    Larkum, Anthony W D; Kühl, Michael

    2005-01-01

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

  20. Biology of corals and coral reefs

    Digital Repository Service at National Institute of Oceanography (India)

    Rajkumar, R.; Parulekar, A.H.

    on the systematic position is presented. The general structure is depicted with illustrations. Physiology part is updated to current knowledge on reproduction, nutrition and excretion of corals. The coral reefs section begins with status of world reefs...

  1. Notes on the instability of extracted chlorophyll and a reported effect of ozone on lichen algae

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D H

    1980-01-01

    Recently Rosentreter and Ahmadjian reported on the effects of ozone on the chlorophyll content of Cladonia arbuscula and isolated Trebouxia cells. However, the chlorophyll data they presented, even for the control, unozone-treated material, appears to be unusual. They reported values of the chlorophyll a/b ratio of 0.308-0.463 from Cladonia arbuscula and 0.345-0.476 for Trebouxia which are substantially lower than other published values. Because chlorophyll b is normally present in green plants as a minor accessory photosynthetic pigment, the suggestion that it was the major chlorophyll component requires some explanation. The purpose of this study is to show that chlorophyll is unstable when extracted into methanol and to suggest that the extraction and storage conditions used by Rosentreter and Ahmadjian may have allowed pigment degradation to occur which thereby accounted for the low chlorophyll a/b ratios they obtained.

  2. Identification of the 7-Hydroxymethyl Chlorophyll a Reductase of the Chlorophyll Cycle in Arabidopsis[W

    Science.gov (United States)

    Meguro, Miki; Ito, Hisashi; Takabayashi, Atsushi; Tanaka, Ryouichi; Tanaka, Ayumi

    2011-01-01

    The interconversion of chlorophyll a and chlorophyll b, referred to as the chlorophyll cycle, plays a crucial role in the processes of greening, acclimation to light intensity, and senescence. The chlorophyll cycle consists of three reactions: the conversions of chlorophyll a to chlorophyll b by chlorophyllide a oxygenase, chlorophyll b to 7-hydroxymethyl chlorophyll a by chlorophyll b reductase, and 7-hydroxymethyl chlorophyll a to chlorophyll a by 7-hydroxymethyl chlorophyll a reductase. We identified 7-hydroxymethyl chlorophyll a reductase, which is the last remaining unidentified enzyme of the chlorophyll cycle, from Arabidopsis thaliana by genetic and biochemical methods. Recombinant 7-hydroxymethyl chlorophyll a reductase converted 7-hydroxymethyl chlorophyll a to chlorophyll a using ferredoxin. Both sequence and biochemical analyses showed that 7-hydroxymethyl chlorophyll a reductase contains flavin adenine dinucleotide and an iron-sulfur center. In addition, a phylogenetic analysis elucidated the evolution of 7-hydroxymethyl chlorophyll a reductase from divinyl chlorophyllide vinyl reductase. A mutant lacking 7-hydroxymethyl chlorophyll a reductase was found to accumulate 7-hydroxymethyl chlorophyll a and pheophorbide a. Furthermore, this accumulation of pheophorbide a in the mutant was rescued by the inactivation of the chlorophyll b reductase gene. The downregulation of pheophorbide a oxygenase activity is discussed in relation to 7-hydroxymethyl chlorophyll a accumulation. PMID:21934147

  3. Coral uptake of inorganic phosphorus and nitrogen negatively affected by simultaneous changes in temperature and pH.

    Directory of Open Access Journals (Sweden)

    Claire Godinot

    Full Text Available The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO(2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i at three pH(T conditions (8.1, 7.8, and 7.5 and normal temperature (26°C, ii at three temperature conditions (26°, 29°C, and 33°C and normal pH(T (8.1, and iii at three pH(T conditions (8.1, 7.8, and 7.5 and elevated temperature (33°C. After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pH(T 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C and low pH(T (7.5 resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pH(T = 8.1. These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification.

  4. Coral Uptake of Inorganic Phosphorus and Nitrogen Negatively Affected by Simultaneous Changes in Temperature and pH

    Science.gov (United States)

    Godinot, Claire; Houlbrèque, Fanny

    2011-01-01

    The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i) at three pHT conditions (8.1, 7.8, and 7.5) and normal temperature (26°C), ii) at three temperature conditions (26°, 29°C, and 33°C) and normal pHT (8.1), and iii) at three pHT conditions (8.1, 7.8, and 7.5) and elevated temperature (33°C). After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pHT 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C) alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C) and low pHT (7.5) resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pHT = 8.1). These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification. PMID:21949839

  5. Content

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    secondary levels. In subject matter didactics, the question of content is more developed, but it is still mostly confined to teaching on lower levels. As for higher education didactics, discussions on selection of content are almost non-existent on the programmatic level. Nevertheless, teachers are forced...... curriculum, in higher education, and to generate analytical categories and criteria for selection of content, which can be used for systematic didactical reflection. The larger project also concerns reflection on and clarification of the concept of content, including the relation between content at the level......Aim, content and methods are fundamental categories of both theoretical and practical general didactics. A quick glance in recent pedagogical literature on higher education, however, reveals a strong preoccupation with methods, i.e. how teaching should be organized socially (Biggs & Tang, 2007...

  6. Efficiency of portable chlorophyll meters in assessing the nutritional status of wheat plants

    Directory of Open Access Journals (Sweden)

    Alessana F. Schlichting

    2015-12-01

    Full Text Available ABSTRACT The objective of this study was to verify the efficiency of two portable chlorophyll meters (Minolta SPAD® 502 and Falker ClorofiLOG® 1030 in assessing the nutritional status of wheat plants, correlating the indices from the devices and the direct determination of chlorophyll content with the concentration of nitrogen (N in the plant. The experiment was conducted in a greenhouse, in pots with 5 dm3 of Oxisol, in a completely randomized design, with six N doses (0, 80, 160, 240, 320 and 400 mg dm-3 and five replicates. At 47 days after emergence, the readings of SPAD and Falker indices and the quantification of chlorophyll content and N concentration in wheat plants were performed, as well as analysis of variance and correlation test, both at 0.05 probability level. The chlorophyll meters Minolta SPAD® 502 and Falker ClorofiLOG® 1030 do not differ with respect to the indirect determination of chlorophyll in wheat plants. The Falker chlorophyll index was statistically equal to the chlorophyll content. Indirect chlorophyll indices and chlorophyll content showed a high correlation with the N concentration in the plant.

  7. Mesopredator trophodynamics on thermally stressed coral reefs

    Science.gov (United States)

    Hempson, Tessa N.; Graham, Nicholas A. J.; MacNeil, M. Aaron; Hoey, Andrew S.; Almany, Glenn R.

    2018-03-01

    Ecosystems are becoming vastly modified through disturbance. In coral reef ecosystems, the differential susceptibility of coral taxa to climate-driven bleaching is predicted to shift coral assemblages towards reefs with an increased relative abundance of taxa with high thermal tolerance. Many thermally tolerant coral species are characterised by low structural complexity, with reduced habitat niche space for the small-bodied coral reef fishes on which piscivorous mesopredators feed. This study used a patch reef array to investigate the potential impacts of climate-driven shifts in coral assemblages on the trophodynamics of reef mesopredators and their prey communities. The `tolerant' reef treatment consisted only of coral taxa of low susceptibility to bleaching, while `vulnerable' reefs included species of moderate to high thermal vulnerability. `Vulnerable' reefs had higher structural complexity, and the fish assemblages that established on these reefs over 18 months had higher species diversity, abundance and biomass than those on `tolerant' reefs. Fish assemblages on `tolerant' reefs were also more strongly influenced by the introduction of a mesopredator ( Cephalopholis boenak). Mesopredators on `tolerant' reefs had lower lipid content in their muscle tissue by the end of the 6-week experiment. Such sublethal energetic costs can compromise growth, fecundity, and survivorship, resulting in unexpected population declines in long-lived mesopredators. This study provides valuable insight into the altered trophodynamics of future coral reef ecosystems, highlighting the potentially increased vulnerability of reef fish assemblages to predation as reef structure declines, and the cost of changing prey availability on mesopredator condition.

  8. Dietary shift in juvenile coral trout ( Plectropomus maculatus) following coral reef degradation from a flood plume disturbance

    Science.gov (United States)

    Wen, Colin K. C.; Bonin, Mary C.; Harrison, Hugo B.; Williamson, David H.; Jones, Geoffrey P.

    2016-06-01

    Acute environmental disturbances impact on habitat quality and resource availability, which can reverberate through trophic levels and become apparent in species' dietary composition. In this study, we observed a distinct dietary shift of newly settled and juvenile coral trout ( Plectropomus maculatus) following severe coral reef habitat degradation after a river flood plume affected the Keppel Islands, Australia. Hard coral cover declined by ~28 % in the 2 yr following the 2010-2011 floods, as did the abundance of young coral trout. Gut contents analysis revealed that diets had shifted from largely crustacean-based to non-preferred prey fishes following the disturbances. These results suggest that newly settled and juvenile coral trout modify their diet and foraging strategy in response to coral habitat degradation. This bottom-up effect of habitat degradation on the diet of a top coral reef predator may incur a metabolic cost, with subsequent effects on growth and survival.

  9. Mycosporine-like amino acids in six scleractinian coral species

    Directory of Open Access Journals (Sweden)

    Ahmad A. Al-Utaibi

    2009-03-01

    Full Text Available Mycosporine-like amino acids (MAAs were studied in stony coral species (Fungiidae along the Eastern coast of the Red Sea. Six species - Fungia scutaria, F. danai, F. corona, F. repanda, Ctenactis echinata and Lithophyllor lobata - were examined for MAAs at water depths of 5, 10, 15 and 20 m. Protein and chlorophyll were also determined and showed higher contents in winter than in summer. Generally, the total content of MAAs in summer was found to be approximately three times greater than in winter. Overall, concentrations of MAAs were greatest at a depth of 5 m. Porphyra-334 was the most abundant MAA in F. Scutaria and F. Danai, whereas asterina-330 was either not detectable (e.g. L. lobata or present in low concentrations (e.g. F. danai, F. repanda and C. echinata. Shinorine was not detected in F. danai or L. lobata. Both C. echinata and L. Lobata had the lowest concentrations of MAAs, presumably because of their large calcareous skeletons. The variation in MAA concentrations among seasons and water depths is probably due to a number of factors, including the intensity of solar radiation, turbidity and phylogenetic variation.

  10. Instability of chlorophyll in yellow lupin seedlings grown in soil contaminated with ciprofloxacin and tetracycline.

    Science.gov (United States)

    Rydzyński, Dariusz; Piotrowicz-Cieślak, Agnieszka I; Grajek, Hanna; Michalczyk, Dariusz J

    2017-10-01

    With increasing soil concentrations of ciprofloxacin and tetracycline a decrease of leaf chlorophyll content was observed. Tetracycline was more detrimental than ciprofloxacin. The chlorophyll content in plants growing for ten days on a tetracycline containing soil decreased by 68%. The decrease of chlorophyll concentration was even sharper in new leaves that formed after application of the antibiotic (up to 81% drop). The comparison of absorption spectra of commercial, reagent grade chlorophyll, alone and incubated with antibiotics, has shown that ciprofloxacin and tetracycline can react directly with chlorophyll and decrease its concentration by 47.7% and 48.5%, respectively. The changes in fluorescence spectra confirmed the formation of chlorophyll degradation product. The chlorophyll decay was a second order reaction and depended on antibiotic concentration and duration of exposure. Reaction rate constants differed with antibiotics and their soil concentrations. With increasing contents of antibiotics in soil the constant of chlorophyll degradation rate in lupin plants increased from k = 870 M -1 day -1 for 3 mg ciprofloxacin to k = 2490 M -1 day -1 for 90 mg ciprofloxacin, and in the case of tetracycline the reaction rate constant increased from k = 1330 M -1 day -1 to k = 2910 M -1 day -1 . The sensitivity of chlorophyll to ciprofloxacin and tetracycline was confirmed by determining EC and TU indices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Tomato seeds maturity detection system based on chlorophyll fluorescence

    Science.gov (United States)

    Li, Cuiling; Wang, Xiu; Meng, Zhijun

    2016-10-01

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

  12. In situ Analysis of Coral Recruits Using Fluorescence Imaging

    Directory of Open Access Journals (Sweden)

    Adi Zweifler

    2017-09-01

    Full Text Available Recruitment is a fundamental process that influences coral population dynamics as well as reef community structure. To date, coral recruitment success rates are poorly quantified because survey methods are labor-intensive and require manual interpretation. Thus, they are prone to human errors and have low repeatability—a gap we aim to bridge in this research. Since both corals and their symbiotic algae contain fluorescent pigments (chlorophyll and fluorescent proteins, we used the non-invasive Fluorescence Imaging System (FluorIS and developed a methodology to acquire daytime fluorescent photographs and identify coral recruits in them. We tested our method by monitoring 20 random quadrats at two sites in the Gulf of Aqaba, Israel. The quadrats were surveyed once a month for 8 months in order to track the settlement, mortality and survival rates of new coral recruits. We demonstrate daytime imaging using our method and identification of coral recruits as small as 1 mm in diameter, in a 20 × 20 cm quadrat. Our results show that this photographic method reduces surveyor errors and improves precision. The surveys revealed that on average, there are ~2 new coral recruit settlements (<2 cm for a quadrat (40 cm2 per month and that 83% of them survive the first month. Our study suggests a relative stability in the Gulf of Aqaba coral population during the survey period. The ability to survey recruits during the day using low-cost, easy-to-use photographic equipment has the potential to contribute significantly to the standardization of coral reef monitoring and management tools, at a time when the world's coral reefs are declining due to local and global stressors.

  13. Study of 660 nm laser-induced photoluminescence of chlorophyll-a and its applications

    International Nuclear Information System (INIS)

    Song, Y; Zhang, D X; Zhang, H J

    2007-01-01

    Based on the phenomenon of chlorophyll a photoluminescence, this paper introduces a new method to measure the chlorophyll a content, using 660nm laser diode as a new kind of light source to stimulate fluorescence as well as combining a fiber and spectrum technique. We analyze the characteristics of laser-induced fluorescence spectrum of chlorophyll a and then put forward the new method using two parameters, the relative fluorescence intensity and fluorescence intensity ratio F685/F735, to measure the chlorophyll a content in the water and green leaves respectively. The experimental results indicate that it is completely feasible to give a visual judgment for chlorophyll a content, according to the fluorescence emission spectrum of chlorophyll a. Subsequently, it is verified by three kinds of typical applications. All of these provide a new kind of light source to develop the chlorophyll a fluorometry and further give a technical foundation of on-spot monitoring the chlorophyll a content in the ocean or in green leaves

  14. Mahalanobis distance screening of Arabidopsis mutants with chlorophyll fluorescence

    Czech Academy of Sciences Publication Activity Database

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

    2010-01-01

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

  15. Effect of organic and inorganic fertilizer on yield and chlorophyll ...

    African Journals Online (AJOL)

    The effects of amending soil with organic (poultry manure) and inorganic fertilizer on yield and chlorophyll content of maize (Zea mays L.) and sorghum (Sorghum bicolour (L.) Moench) was carried out at the Teaching and Research (T&R) Farm of the Obafemi Awolowo University, (O.A.U.) Ile - Ife, Nigeria. The experiment ...

  16. Physiological and biogeochemical traits of bleaching and recovery in the mounding species of coral Porites lobata: implications for resilience in mounding corals.

    Directory of Open Access Journals (Sweden)

    Stephen J Levas

    Full Text Available Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ(13C of the skeletal, δ(13C, and δ(15N of the animal host and endosymbiont fractions. Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via (13C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic

  17. Feeding sustains photosynthetic quantum yield of a scleractinian coral during thermal stress.

    Science.gov (United States)

    Borell, Esther M; Bischof, Kai

    2008-10-01

    Thermal resistance of the coral-zooxanthellae symbiosis has been associated with chronic photoinhibition, increased antioxidant activity and protein repair involving high demands of nitrogen and energy. While the relative importance of heterotrophy as a source of nutrients and energy for cnidarian hosts, and as a means of nitrogen acquisition for their zooxanthellae, is well documented, the effect of feeding on the thermal sensitivity of the symbiotic association has been so far overlooked. Here we examine the effect of zooplankton feeding versus starvation on the bleaching susceptibility and photosynthetic activity of photosystem II (PSII) of zooxanthellae in the scleractinian coral Stylophora pistillata in response to thermal stress (daily temperature rises of 2-3 degrees C) over 10 days, employing pulse-amplitude-modulated chlorophyll fluorometry. Fed and starved corals displayed a decrease in daily maximum potential quantum yield (F (v)/F (m)) of PSII, effective quantum yield (F/F (m)') and relative electron transport rates over the course of 10 days. However after 10 days of exposure to elevated temperature, F (v)/F (m) of fed corals was still 50-70% higher than F (v)/F (m) of starved corals. Starved corals showed strong signs of chronic photoinhibition, which was reflected in a significant decline in nocturnal recovery rates of PSII relative to fed corals. This was paralleled by the progressive inability to dissipate excess excitation energy via non-photochemical quenching (NPQ). After 10 days, NPQ of starved corals had decreased by about 80% relative to fed corals. Feeding treatment had no significant effect on chlorophyll a and c (2) concentrations and zooxanthellae densities, but the mitotic indices were significantly lower in starved than in fed corals. Collectively the results indicate that exogenous food may reduce the photophysiological damage of zooxanthellae that typically leads to bleaching and could therefore play an important role in mediating the

  18. Coral reefs - Specialized ecosystems

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.

    This paper discusses briefly some aspects that characterize and differentiate coral reef ecosystems from other tropical marine ecosystems. A brief account on the resources that are extractable from coral reefs, their susceptibility to natural...

  19. Optimal leaf positions for chlorophyll meter measurement in rice

    Directory of Open Access Journals (Sweden)

    Zhaofeng eYuan

    2016-05-01

    Full Text Available The Soil Plant Analysis Development (SPAD chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.. A flatbed color scanner was used to map the dynamic chlorophyll distribution and irregular leaf shapes. Calculus algorithm was adopted to estimate the potential positions for SPAD meter measurement along the leaf blade. Data generated by the flatbed color scanner and SPAD meter were analysed simultaneously. The results suggested that a position 2/3 of the distance from the leaf base to the apex (2/3 position could represent the chlorophyll content of the entire leaf blade, as indicated by the relatively low variance of measurements at that positon. SPAD values based on di-positional leaves and the extracted chlorophyll a and b contents were compared. This comparison showed that the 2/3 position on the lower leaves tended to be more sensitive to changes in chlorophyll content. Finally, the 2/3 position and average SPAD values of the fourth fully expanded leaf from the top were compared with leaf nitrogen concentration. The results showed the 2/3 position on that leaf was most suitable for predicting the nitrogen status of rice. Based on these results, we recommend making SPAD measurements at the 2/3 position on the fourth fully expanded leaf from the top. The coupling of dynamic chlorophyll distribution and irregular leaf shapes information can provide a promising approach for the calibration of SPAD meter measurement, which can further benefit the in situ nitrogen management by providing reliable estimation of crops nitrogen nutrition status.

  20. Differential effects of glyphosate and aminomethylphosphonic acid (AMPA) on photosynthesis and chlorophyll metabolism in willow plants.

    Science.gov (United States)

    Gomes, Marcelo Pedrosa; Le Manac'h, Sarah Gingras; Maccario, Sophie; Labrecque, Michel; Lucotte, Marc; Juneau, Philippe

    2016-06-01

    We used a willow species (Salix miyabeana cultivar SX64) to examine the differential secondary-effects of glyphosate and aminomethylphosphonic acid (AMPA), the principal glyphosate by-product, on chlorophyll metabolism and photosynthesis. Willow plants were treated with different concentrations of glyphosate (equivalent to 0, 1.4, 2.1 and 2.8kgha(-1)) and AMPA (equivalent to 0, 0.28, 1.4 and 2.8kgha(-1)) and evaluations of pigment contents, chlorophyll fluorescence, and oxidative stress markers (hydrogen peroxide content and antioxidant enzyme activities) in leaves were performed after 12h of exposure. We observed that AMPA and glyphosate trigger different mechanisms leading to decreases in chlorophyll content and photosynthesis rates in willow plants. Both chemicals induced ROS accumulation in willow leaves although only glyphosate-induced oxidative damage through lipid peroxidation. By disturbing chlorophyll biosynthesis, AMPA induced decreases in chlorophyll contents, with consequent effects on photosynthesis. With glyphosate, ROS increases were higher than the ROS-sensitive threshold, provoking chlorophyll degradation (as seen by pheophytin accumulation) and invariable decreases in photosynthesis. Peroxide accumulation in both AMPA and glyphosate-treated plants was due to the inhibition of antioxidant enzyme activities. The different effects of glyphosate on chlorophyll contents and photosynthesis as described in the literature may be due to various glyphosate:AMPA ratios in those plants. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Complexes and aggregates of chlorophylls

    NARCIS (Netherlands)

    Kooyman, R.P.H.

    1980-01-01

    Chlorophyll (Chl) molecules can form complexes in two important ways: by ligation at the magnesium atom and/or by hydrogen bonding at the keto- carbonyl group. Under certain conditions these processes may give rise to dimer formation. This thesis describes some properties of complexes and dimers of

  2. Chlorophyll as a biomarker for early disease diagnosis

    Science.gov (United States)

    Manzoor Atta, Babar; Saleem, M.; Ali, Hina; Arshad, Hafiz Muhammad Imran; Ahmed, M.

    2018-06-01

    The current study was designed to identify the stage for the diagnosis of disease before visible symptoms appeared. Fluorescence spectroscopy has been employed to identify disease signatures for its early diagnosis in rice plant leaves. Bacterial leaf blight (BLB) diseased and healthy leaf samples were collected from the rice fields in September, 2017 which were then used to record spectra using an excitation wavelength at 410 nm. The spectral range of emission was set from 420 to 800 nm which covers the blue–green and the chlorophyll bands. It was found that diseased leaves have a narrower ‘chlorophyll a’ band than healthy ones, and furthermore, that the emission band at 730 nm was either declined or depleted in the sample with high infection symptoms. In contrast, the blue–green region was observed to increase due to the emergence of disease. As the band intensity of chlorophyll decreases during infection, this decrease in chlorophyll content and increase in the blue–green spectral region could provide a new approach for predicting BLB at an early stage. The important finding was that the chlorophyll degradation and rise in the blue–green region take place in leaves with BLB or during BLB infection. Principal component analysis has been applied to spectral data which successfully separated diseased samples from healthy ones even with very small spectral variations.

  3. Characterization of chlorophyll binding to LIL3.

    Science.gov (United States)

    Mork-Jansson, Astrid Elisabeth; Eichacker, Lutz Andreas

    2018-01-01

    The light harvesting like protein 3 (LIL 3) from higher plants, has been linked to functions in chlorophyll and tocopherol biosynthesis, photo-protection and chlorophyll transfer. However, the binding of chlorophyll to LIL3 is unclear. We present a reconstitution protocol for chlorophyll binding to LIL3 in DDM micelles. It is shown in the absence of lipids and carotenoids that reconstitution of chlorophyll binding to in vitro expressed LIL3 requires pre-incubation of reaction partners at room temperature. We show chlorophyll a but not chlorophyll b binding to LIL3 at a molar ratio of 1:1. Neither dynamic light scattering nor native PAGE, enabled a discrimination between binding of chlorophyll a and/or b to LIL3.

  4. HAAR TRANSFORM BASED ESTIMATION OF CHLOROPHYLL AND STRUCTURE OF THE LEAF

    OpenAIRE

    Abhinav Arora; R. Menaka; Shivangi Gupta; Archit Mishra

    2013-01-01

    In this paper, the health of a plant is estimated using various non-destructive Image Processing Techniques. Chlorophyll content was detected based on colour Image Processing. The Haar transform is applied to get size of leaf and the parameters.

  5. Chlorophyll metabolism in pollinated vs. parthenocarpic fig fruits throughout development and ripening.

    Science.gov (United States)

    Rosianskey, Yogev; Dahan, Yardena; Yadav, Sharawan; Freiman, Zohar E; Milo-Cochavi, Shira; Kerem, Zohar; Eyal, Yoram; Flaishman, Moshe A

    2016-08-01

    Expression of 13 genes encoding chlorophyll biosynthesis and degradation was evaluated. Chlorophyll degradation was differentially regulated in pollinated and parthenocarpic fig fruits, leading to earlier chlorophyll degradation in parthenocarpic fruits. Varieties of the common fig typically yield a commercial summer crop that requires no pollination, although it can be pollinated. Fig fruit pollination results in larger fruit size, greener skin and darker interior inflorescence color, and slows the ripening process compared to non-pollinated fruits. We evaluated the effect of pollination on chlorophyll content and levels of transcripts encoding enzymes of the chlorophyll metabolism in fruits of the common fig 'Brown Turkey'. We cloned and evaluated the expression of 13 different genes. All 13 genes showed high expression in the fruit skin, inflorescences and leaves, but extremely low expression in roots. Pollination delayed chlorophyll breakdown in the ripening fruit skin and inflorescences. This was correlated with the expression of genes encoding enzymes in the chlorophyll biosynthesis and degradation pathways. Expression of pheophorbide a oxygenase (PAO) was strongly negatively correlated with chlorophyll levels during ripening in pollinated fruits; along with its high expression levels in yellow leaves, this supports a pivotal role for PAO in chlorophyll degradation in figs. Normalizing expression levels of all chlorophyll metabolism genes in the pollinated and parthenocarpic fruit skin and inflorescences showed three synthesis (FcGluTR1, FcGluTR2 and FcCLS1) and three degradation (FcCLH1, FcCLH2 and FcRCCR1) genes with different temporal expression in the pollinated vs. parthenocarpic fruit skin and inflorescences. FcCAO also showed different expressions in the parthenocarpic fruit skin. Thus, chlorophyll degradation is differentially regulated in the pollinated and parthenocarpic fruit skin and inflorescences, leading to earlier and more sustained

  6. Contents

    Directory of Open Access Journals (Sweden)

    Editor IJRED

    2012-11-01

    Full Text Available International Journal of Renewable Energy Development www.ijred.com Volume 1             Number 3            October 2012                ISSN 2252- 4940   CONTENTS OF ARTICLES page Design and Economic Analysis of a Photovoltaic System: A Case Study 65-73 C.O.C. Oko , E.O. Diemuodeke, N.F. Omunakwe, and E. Nnamdi     Development of Formaldehyde Adsorption using Modified Activated Carbon – A Review 75-80 W.D.P Rengga , M. Sudibandriyo and M. Nasikin     Process Optimization for Ethyl Ester Production in Fixed Bed Reactor Using Calcium Oxide Impregnated Palm Shell Activated Carbon (CaO/PSAC 81-86 A. Buasri , B. Ksapabutr, M. Panapoy and N. Chaiyut     Wind Resource Assessment in Abadan Airport in Iran 87-97 Mojtaba Nedaei       The Energy Processing by Power Electronics and its Impact on Power Quality 99-105 J. E. Rocha and B. W. D. C. Sanchez       First Aspect of Conventional Power System Assessment for High Wind Power Plants Penetration 107-113 A. Merzic , M. Music, and M. Rascic   Experimental Study on the Production of Karanja Oil Methyl Ester and Its Effect on Diesel Engine 115-122 N. Shrivastava,  , S.N. Varma and M. Pandey  

  7. Isolation of chlorophyll a from spinach leaves

    Directory of Open Access Journals (Sweden)

    E.D. Dikio

    2008-08-01

    Full Text Available An efficient method for separating chlorophyll a from spinach leaves by column chromatography and solvent extraction techniques has been developed. The purity and identity of the chlorophyll a have been confirmed by UV-Vis, IR and mass spectrometry. Yields from 100 g of freeze-dried spinach were 23 – 24 mg of chlorophyll a.

  8. Relationship between chlorophyll density and SPAD chlorophyll meter reading for Jerusalem artichoke (Helianthus tuberosus L.)

    Science.gov (United States)

    Chlorophyll is an indicator of crop health and productivity. Measuring chlorophyll is usually done directly and requires significant time and resources. Indirect measurement of chlorophyll density using a handheld portable chlorophyll meter can reduce time. However, this information is very limit...

  9. Nondestructive and intuitive determination of circadian chlorophyll rhythms in soybean leaves using multispectral imaging

    Science.gov (United States)

    Pan, Wen-Juan; Wang, Xia; Deng, Yong-Ren; Li, Jia-Hang; Chen, Wei; Chiang, John Y.; Yang, Jian-Bo; Zheng, Lei

    2015-01-01

    The circadian clock, synchronized by daily cyclic environmental cues, regulates diverse aspects of plant growth and development and increases plant fitness. Even though much is known regarding the molecular mechanism of circadian clock, it remains challenging to quantify the temporal variation of major photosynthesis products as well as their metabolic output in higher plants in a real-time, nondestructive and intuitive manner. In order to reveal the spatial-temporal scenarios of photosynthesis and yield formation regulated by circadian clock, multispectral imaging technique has been employed for nondestructive determination of circadian chlorophyll rhythms in soybean leaves. By utilizing partial least square regression analysis, the determination coefficients R2, 0.9483 for chlorophyll a and 0.8906 for chlorophyll b, were reached, respectively. The predicted chlorophyll contents extracted from multispectral data showed an approximately 24-h rhythm which could be entrained by external light conditions, consistent with the chlorophyll contents measured by chemical analyses. Visualization of chlorophyll map in each pixel offers an effective way to analyse spatial-temporal distribution of chlorophyll. Our results revealed the potentiality of multispectral imaging as a feasible nondestructive universal assay for examining clock function and robustness, as well as monitoring chlorophyll a and b and other biochemical components in plants. PMID:26059057

  10. Bone marrow mesenchymal stem cells differentiation and proliferation on the surface of coral implant

    International Nuclear Information System (INIS)

    Al-Salihi, K.A.; Samsudin, A.R.

    2004-01-01

    This study was designed to evaluate the ability of natural coral implant to provide an environment for marrow cells to differentiate into osteoblasts and function suitable for mineralized tissue formation. DNA content, alkaline phosptatase (ALP) activity, calcium (Ca) content and mineralized nodules, were measured at day 3, day 7 and day 14, in rat bone marrow stromal cells cultured with coral discs glass discs, while cells alone and coral disc alone cultured as control. DNA content, ALP activity, Ca content measurements showed no difference between coral, glass and cells groups at 3 day which were higher than control (coral disc alone), but there were higher asurement at day 7 and 14 in the cell cultured on coral than on glass discs, control cells and control coral discs. Mineralized nodules formation (both in area and number) was more predominant on the coral surface than in control groups. These results showed that natural coral implant provided excellent and favorable situation for marrow cell to differentiate to osteoblasts, lead to large amount of mineralized tissue formation on coral surface. This in vitro result could explain the rapid bone bonding of coral in vivo. (Author)

  11. Corals diseases are a major cause of coral death

    Science.gov (United States)

    Corals, like humans, are susceptible to diseases. Some coral diseases are associated with pathogenic bacteria; however, the causes of most remain unknown. Some diseases trigger rapid and extensive mortality, while others slowly cause localized color changes or injure coral tiss...

  12. Changes in the fluorescence of the Caribbean coral Montastraea faveolata during heat-induced bleaching

    Science.gov (United States)

    Zawada, David G.; Jaffe, J.S.

    2003-01-01

    In order to evaluate the response of commonly occurring green and orange fluorescent host-based pigments, a thermal stress experiment was performed on specimens of the Caribbean coral Montastraea faveolata. Seven paired samples were collected from a small oceanic reef near Lee Stocking Island in the Bahamas. Seven of the fourteen corals were subjected to elevated temperatures for 28 d, followed by a recovery period lasting 53 d. Throughout the experiment, high-resolution (~400 µm pixel-1) multispectral images of induced fluorescence were recorded at wavelengths corresponding to the green and orange host pigments, plus chlorophyll. These images revealed that the fluorescence of both host pigments was concentrated at polyp centers and declined by 70–90% in regions between polyps. Chlorophyll fluorescence, however, was distributed almost uniformly across the entire coral surface, but with decreases of 10–30% around polyp centers. A normalized difference ratio between the green and orange pigments (GO ratio) was developed to facilitate comparison with chlorophyll fluorescence as a bleaching indicator. Analysis showed a high correspondence between a sustained GO ratio of less than zero and the death of corals. Finally, this ratio was resistant to contamination from other sources of chlorophyll fluorescence, such as filamentous algae.

  13. Control of quantum interference of an excitonic wave in a chlorophyll chain with a chlorophyll ring

    International Nuclear Information System (INIS)

    Hong, Suc-Kyoung; Nam, Seog-Woo; Yeon, Kyu-Hwang

    2010-01-01

    The quantum interference of an excitonic wave and its coherent control in a nanochain with a nanoring are studied. The nanochain is comprised of six chlorophylls, where four chlorophylls compose the nanoring and two chlorophylls are attached at two opposite sites on the nanoring. The exciton dynamics and the correlation of the excitation between chlorophylls are analyzed for a given configurational arrangement and dipolar orientation of the chlorophylls. The results of this study show that the excitation at specified chlorophylls is suppressed or enhanced by destructive or constructive interference of the excitonic wave in the chlorophyll nanochain.

  14. Additive effects of the herbicide glyphosate and elevated temperature on the branched coral Acropora formosa in Nha Trang, Vietnam.

    Science.gov (United States)

    Amid, C; Olstedt, M; Gunnarsson, J S; Le Lan, H; Tran Thi Minh, H; Van den Brink, P J; Hellström, M; Tedengren, M

    2018-05-01

    The combined effects of the herbicide glyphosate and elevated temperature were studied on the tropical staghorn coral Acropora formosa, in Nha Trang bay, Vietnam. The corals were collected from two different reefs, one close to a polluted fish farm and one in a marine-protected area (MPA). In the laboratory, branches of the corals were exposed to the herbicide glyphosate at ambient (28 °C) and at 3 °C elevated water temperatures (31 °C). Effects of herbicide and elevated temperature were studied on coral bleaching using photography and digital image analysis (new colorimetric method developed here based on grayscale), chlorophyll a analysis, and symbiotic dinoflagellate (Symbiodinium, referred to as zooxanthellae) counts. All corals from the MPA started to bleach in the laboratory before they were exposed to the treatments, indicating that they were very sensitive, as opposed to the corals collected from the more polluted site, which were more tolerant and showed no bleaching response to temperature increase or herbicide alone. However, the combined exposure to the stressors resulted in significant loss of color, proportional to loss in chlorophyll a and zooxanthellae. The difference in sensitivity of the corals collected from the polluted site versus the MPA site could be explained by different symbiont types: the resilient type C3u and the stress-sensitive types C21 and C23, respectively. The additive effect of elevated temperatures and herbicides adds further weight to the notion that the bleaching of coral reefs is accelerated in the presence of multiple stressors. These results suggest that the corals in Nha Trang bay have adapted to the ongoing pollution to become more tolerant to anthropogenic stressors, and that multiple stressors hamper this resilience. The loss of color and decrease of chlorophyll a suggest that bleaching is related to concentration of chloro-pigments. The colorimetric method could be further fine-tuned and used as a precise, non

  15. Negative response of photosynthesis to natural and projected high seawater temperatures estimated by pulse amplitude modulation fluorometry in a temperate coral.

    Science.gov (United States)

    Caroselli, Erik; Falini, Giuseppe; Goffredo, Stefano; Dubinsky, Zvy; Levy, Oren

    2015-01-01

    Balanophyllia europaea is a shallow water solitary zooxanthellate coral, endemic to the Mediterranean Sea. Extensive field studies across a latitudinal temperature gradient highlight detrimental effects of rising temperatures on its growth, demography, and skeletal characteristics, suggesting that depression of photosynthesis at high temperatures might cause these negative effects. Here we test this hypothesis by analyzing, by means of pulse amplitude modulation fluorometry, the photosynthetic efficiency of B. europaea specimens exposed in aquaria to the annual range of temperatures experienced in the field (13, 18, and 28°C), and two extreme temperatures expected for 2100 as a consequence of global warming (29 and 32°C). The indicators of photosynthetic performance analyzed (maximum and effective quantum yield) showed that maximum efficiency was reached at 20.0-21.6°C, slightly higher than the annual mean temperature in the field (18°C). Photosynthetic efficiency decreased from 20.0 to 13°C and even more strongly from 21.6 to 32°C. An unusual form of bleaching was observed, with a maximum zooxanthellae density at 18°C that strongly decreased from 18 to 32°C. Chlorophyll a concentration per zooxanthellae cell showed an opposite trend as it was minimal at 18°C and increased from 18 to 32°C. Since the areal chlorophyll concentration is the product of the zooxanthellae density and its cellular content, these trends resulted in a homogeneous chlorophyll concentration per coral surface across temperature treatments. This confirms that B. europaea photosynthesis is progressively depressed at temperatures >21.6°C, supporting previous hypotheses raised by the studies on growth and demography of this species. This study also confirms the threats posed to this species by the ongoing seawater warming.

  16. Negative response of photosynthesis to natural and projected high seawater temperatures estimated by pulse amplitude modulation fluorometry in a temperate coral

    Directory of Open Access Journals (Sweden)

    Erik eCaroselli

    2015-11-01

    Full Text Available Balanophyllia europaea is a shallow water solitary zooxanthellate coral, endemic to the Mediterranean Sea. Extensive field studies across a latitudinal temperature gradient highlight detrimental effects of rising temperatures on its growth, demography and skeletal characteristics, suggesting that depression of photosynthesis at high temperatures might cause these negative effects. Here we test this hypothesis by analyzing, by means of pulse amplitude modulation fluorometry, the photosynthetic efficiency of B. europaea specimens exposed in aquaria to the annual range of temperatures experienced in the field (13°C, 18°C, and 28°C, and two extreme temperatures expected for 2100 as a consequence of global warming (29°C and 32°C. The indicators of photosynthetic performance analyzed (maximum and effective quantum yield showed that maximum efficiency was reached at 20.0-21.6°C, slightly higher than the annual mean temperature in the field (18°C. Photosynthetic efficiency decreased from 20.0°C to 13°C and even more strongly from 21.6°C to 32°C. An unusual form of bleaching was observed, with a maximum zooxanthellae density at 18°C that strongly decreased from 18°C to 32°C. Chlorophyll a concentration per zooxanthellae cell showed an opposite trend as it was minimal at 18°C and increased from 18°C to 32°C. Since the areal chlorophyll concentration is the product of the zooxanthellae density and its cellular content, these trends resulted in a homogeneous chlorophyll concentration per coral surface across temperature treatments. This confirms that B. europaea photosynthesis is progressively depressed at temperatures >21.6°C, supporting previous hypotheses raised by the studies on growth and demography of this species. This study also confirms the threats posed to this species by the ongoing seawater warming.

  17. 443 ANTHROPOGENIC IMPACTS ON CORAL REEFS AND THEIR ...

    African Journals Online (AJOL)

    Osondu

    Data collection methodology included household questionnaire survey, key informant interviews, participant .... Anthropogenic Impacts on Coral Reefs and Their Effect on Fishery ................Mbije & ... common along Kilwa coastline, away of large markets ... questionnaire whereas content analysis was used for analyzing ...

  18. The ecotoxicology of vegetable versus mineral based lubricating oils 3. Coral fertilization and adult corals

    International Nuclear Information System (INIS)

    Mercurio, Philip; Negri, Andrew P.; Burns, Kathryn A.; Heyward, Andrew J.

    2004-01-01

    Biodegradable vegetable-derived lubricants (VDL) might be less toxic to marine organisms than mineral-derived oils (MDL) due to the absence of high molecular weight aromatics, but this remains largely untested. In this laboratory study, adult corals and coral gametes were exposed to various concentrations of a two-stroke VDL-1A and a corresponding MDL to determine which lubricant type was more toxic to each life stage. In the fertilization experiment, gametes from the scleractinian coral Acropora microphthalma were exposed to water-accommodated fractions (WAF) of VDL-1A and MDL for four hours. The MDL and VDL-1A WAFs inhibited normal fertilization of the corals at 200 μg l -1 total hydrocarbon content (THC) and 150 μg l -1 THC respectively. Disturbance of a stable coral-dinoflagellate symbiosis is regarded as a valid measure of sub-lethal stress in adult corals. The state of the symbiosis in branchlets of adult colonies of Acropora formosa was monitored using indicators such as dinoflagellate expulsion and dark-adapted photosystem II yields of dinoflagellate (using pulse amplitude modulation fluorescence). An effect on symbiosis was measurable following 48 h exposure to the lubricants at concentrations of 190 μg l -1 and 37 μg l -1 THC for the MDL and VDL-1A respectively. GC/MS revealed that the main constituent of the VDL-1A WAF was the compound coumarin, added by the manufacturer to improve odour. The fragrance containing coumarin was removed from the lubricant formulation and the toxicity towards adult corals re-examined. The coumarin-free VDL-2 exhibited significantly less toxicity towards the adult corals than all of the other oil types tested, with the only measurable effect being a slight but significant drop in photosynthetic efficiency at 280 μg l -1 . - Vegetable-derived lubricants were less toxic to adult corals than their mineral counterparts

  19. Effect of PEG-6000 Imposed Water Deficit on Chlorophyll Metabolism in Maize Leaves

    Directory of Open Access Journals (Sweden)

    Rekha Gadre

    2013-08-01

    Full Text Available Drought stress is one of the major abiotic constraint limiting plant growth and productivity world wide. The current study was undertaken with the aim to investigate the effect of water deficit imposed by PEG-6000, on chlorophyll metabolism in maize leaves to work out the mechanistic details. Leaf segments prepared from primary leaves of etiolated maize seedlings were treated with varying concentrations of polyethylene glycol-6000 (PEG-6000; w/v- 5%, 10%, 20%, 30% in continuous light of intensity 40 Wm-2 at 26±2 °C for 24 h in light chamber. The results demonstrate a concentration dependent decline in chlorophyll content with increasing concentration of polyethylene glycol-6000 (PEG-6000. Reduction in chlorophyll ‘a’ level was to a greater extent than the chlorophyll ‘b’. The RNA content decreased in a concentration dependent manner with PEG, however, proline content increased significantly. Relative water content decreased significantly with the supply of 30% PEG only. A substantial decrease in chlorophyll synthesis due to significant reduction in ALA content and ALAD activity, with no change in chlorophyllase activity with the supply of PEG suggests that water deficit affects chlorophyll formation rather than its degradation.

  20. Short-term assessment of the sediment deposition rate and water conditions during a rainy season on La Azufrada coral reef, Gorgona Island, Colombia

    Directory of Open Access Journals (Sweden)

    Diego F. Lozano-Cortés

    2014-02-01

    Full Text Available One of the major stresses on corals is the settlement of suspended sediment on their surfaces. This leads to the blocking of light, the covering of the coral mucus surface and an increased risk of disease. For this reason sediment deposition on a reef is considered a highly important variable in coral reef studies. With the use of sediment traps and oceanographic sensors, the sediment deposition rate and water conditions during a rainy season (April-May 2009 on a Tropical Eastern Pacific coral reef (La Azufrada at Gorgona Island in Colombia were investigated. To quantify sediment deposition, sediment traps were established in nine stations along the coral reef (three stations per reef zone: backreef, flat and slope. To minimize disturbance by aquatic organisms in the sediment traps these were filled with hypersaline borax-buffered 10% formaline solution before their deployment; animals found in the filter contents were fixed and stored in a 4% formalin solution, frozen and identified in the laboratory. To determine the water conditions, discrete samples of water from 1 m and 10 m depths were collected using a Niskin bottle. Oceanographic variables (temperature, salinity and dissolved oxygen as well as turbidity, chlorophyll and nutrient concentration (nitrite, nitrate and phosphorus were measured in the samples from both depths. Vertical records of temperature and salinity were carried out with a Seabird-19 CTD nearest to La Azufrada and water transparency was measured using a Secchi disk. We found a mean trap collection rate of 23.30±4.34gm-2d-1 and did not detect a significant difference in the trap collection rate among reef zones. The mean temperature and salinity in the coral reef depth zone (0-10m layer were 26.98±0.19°C and 32.60±0.52, respectively. Fourteen taxonomic groups of invertebrates were detected inside the sediment traps with bivalves and copepods being the most abundant and frequen. The findings presented here constitute

  1. Short-term assessment of the sediment deposition rate and water conditions during a rainy season on La Azufrada coral reef, Gorgona Island, Colombia

    KAUST Repository

    Lozano-Cortés, Diego F

    2014-02-01

    One of the major stresses on corals is the settlement of suspended sediment on their surfaces. This leads to the blocking of light, the covering of the coral mucus surface and an increased risk of disease. For this reason sediment deposition on a reef is considered a highly important variable in coral reef studies. With the use of sediment traps and oceanographic sensors, the sediment deposition rate and water conditions during a rainy season (April-May 2009) on a Tropical Eastern Pacific coral reef (La Azufrada) at Gorgona Island in Colombia were investigated. To quantify sediment deposition, sediment traps were established in nine stations along the coral reef (three stations per reef zone: backreef, flat and slope). To minimize disturbance by aquatic organisms in the sediment traps these were filled with hypersaline borax-buffered 10% formaline solution before their deployment; animals found in the filter contents were fixed and stored in a 4% formalin solution, frozen and identified in the laboratory. To determine the water conditions, discrete samples of water from 1 m and 10 m depths were collected using a Niskin bottle. Oceanographic variables (temperature, salinity and dissolved oxygen) as well as turbidity, chlorophyll and nutrient concentration (nitrite, nitrate and phosphorus) were measured in the samples from both depths. Vertical records of temperature and salinity were carried out with a Seabird-19 CTD nearest to La Azufrada and water transparency was measured using a Secchi disk. We found a mean trap collection rate of 23.30±4.34gm-2d-1 and did not detect a significant difference in the trap collection rate among reef zones. The mean temperature and salinity in the coral reef depth zone (0-10m layer) were 26.98±0.19°C and 32.60±0.52, respectively. Fourteen taxonomic groups of invertebrates were detected inside the sediment traps with bivalves and copepods being the most abundant and frequen. The findings presented here constitute the first report

  2. Coral reefs and eutrophication

    International Nuclear Information System (INIS)

    Stambler, N.

    1999-01-01

    Coral reefs are found in oligotrophic waters, which are poor in nutrients such as nitrogen, phosphate, and possibly iron. In spite of this, coral reefs exhibit high gross primary productivity rates. They thrive in oligotrophic conditions because of the symbiotic relationship between corals and dinoflagellate algae (zooxanthellae) embedded in the coral tissue. In their mutualistic symbiosis, the zooxanthellae contribute their photosynthetic capability as the basis for the metabolic energy of the whole association, and eventually of a great part of the entire reef ecosystem

  3. Field Spectroscopy And Spectral Analysis Of Caribbean Scleractinian Reef Corals And Related Benthic Biota

    Science.gov (United States)

    Torres-Perez, J. L.; Guild, L. S.; Armstrong, R.; Corredor, J. E.; Polanco, R.; Zuluaga-Montero, A. B.

    2013-05-01

    Coral reefs are highly heterogenic ecosystems with a plethora of photosynthetic organisms forming most of the benthic communities. Usually coral reef benthos is a composite of reef corals, different groups of algae, seagrasses, sandy bottoms, dead rubble, and even mangrove forests living in a relatively small area. The remote characterization of these important tropical ecosystems represents a challenge to scientists, particularly due to the similarity of the spectral signatures among some of these components. As such, we examined the similarities and differences between nine Scleractinian Caribbean shallow-water reef corals' spectral reflectance curves. Samples were also collected from each species for pigment analysis using High Performance Liquid Chromatography (HPLC). Reflectance curves were obtained with the aid of a GER-1500 hand-held field spectroradiometer enclosed in an underwater housing. Our findings showed that even though most of the pigmentation was directly related to the relationship of corals with their symbiotic dinoflagellates (zooxanthellae), the presence of other endolithic photosynthetic organisms can also contribute to the light absorption of corals and, hence, the reflectance spectra of each species. Also, the relative contribution of chlorophylls vs. carotenes or xanthophylls depends on the coral species with some species relying more on Chlorophyll a and other species relying on Chlorophyl c2 and Peridinin with a small Chlorophyll a component. Pigments associated with the xanthophyll cycle of dinoflagellates (Diadinoxanthin and Diatoxanthin) were detected in most species. Pigments typical of endolithic organisms such as Zeaxanthin, Fucoxanthin, Violaxanthin and Siphonaxanthin were also detected in some coral species. The influence of major pigments on the reflectance curve was evidenced with a 2nd derivative analysis. This could be used to discriminate among most species. Further, an analysis of the integration of the area under the

  4. Lead pollution: effects on chlorophyll. [Phalaris canariensis, Lemna minor, graminaceae

    Energy Technology Data Exchange (ETDEWEB)

    Fiussello, N

    1973-01-01

    The emissions of motors are responsible for the high concentrations of lead in soil and plants near roads. In man, when the concentration of lead in blood exceeds the value of 30 ..mu..g/100 ml, is shown a decrease of haemaglobin and an increase of ALA urinary content. Since the early stages of chlorophyll biosynthetic pathway are similar if not identical with those leading to haem as far as protoporphyrin IX, it is interesting to ascertain if lead can specifically interfere in chlorophyll biosynthesis. In sand cultures with 200 p.p.m. of lead (the conc. in roadside soils), after 2 weeks, wheat shows a diminution of 16,5% in fresh weight 7,5% in dry weight and 6,5% in chlorophyll; Phalaris canariensis shows a diminution of 68% f.w., 41% d.w. and 39% chl. in comparison with the controls. A water-plant, Lemna minor, is more sensitive: the chlorophyll content, referred to dry weight, shows after a week a diminution of 32% and 55% with 10/sup -4/M and 10/sup -3/M lead nitrate. Lead in 200 p.p.m. conc. is surely poisonous against the tested plants but a specific action on chlorophyll synthesis could be accepted, at present, only for Lemna minor. It is possible that in wheat and in Phalaris a part of lead is bound in root-system, the more damaged, while in Lemna it can reach more easily the chloroplasts. At present a detectable increase of ALA, in plants treated with lead, has not been proved both in Graminaceae and in Lemna minor.

  5. Water column productivity and temperature predict coral reef regeneration across the Indo-Pacific.

    Science.gov (United States)

    Riegl, B; Glynn, P W; Wieters, E; Purkis, S; d'Angelo, C; Wiedenmann, J

    2015-02-05

    Predicted increases in seawater temperatures accelerate coral reef decline due to mortality by heat-driven coral bleaching. Alteration of the natural nutrient environment of reef corals reduces tolerance of corals to heat and light stress and thus will exacerbate impacts of global warming on reefs. Still, many reefs demonstrate remarkable regeneration from past stress events. This paper investigates the effects of sea surface temperature (SST) and water column productivity on recovery of coral reefs. In 71 Indo-Pacific sites, coral cover changes over the past 1-3 decades correlated negative-exponentially with mean SST, chlorophyll a, and SST rise. At six monitoring sites (Persian/Arabian Gulf, Red Sea, northern and southern Galápagos, Easter Island, Panama), over half of all corals were <31 years, implying that measured environmental variables indeed shaped populations and community. An Indo-Pacific-wide model suggests reefs in the northwest and central Indian Ocean, as well as the central west Pacific, are at highest risk of degradation, and those at high latitudes the least. The model pinpoints regions where coral reefs presently have the best chances for survival. However, reefs best buffered against temperature and nutrient effects are those that current studies suggest to be most at peril from future ocean acidification.

  6. Chlorophyll as a measure of plant health: Agroecological aspects

    Directory of Open Access Journals (Sweden)

    Danijela Pavlović

    2014-03-01

    Full Text Available As photosynthesis is the basic process during which light energy is absorbed and converted into organic matter, the importance of the plant pigment chlorophyll (a and b forms as an intermediary in transformation of the absorbed solar energy and its activity in the process of photosynthesis and synthesis of organic substances in plants are crucial. Therefore, this paper provides an overview of methods for monitoring the optical activity of chlorophyll molecules and methods (non-destructive and destructive for quantification of chlorophyll in plants. These methods are used to estimate the effects of different stress factors (abiotic, biotic and xenobiotic on the efficiency of photosynthesis and bioproductivity, aiming to assess the impact that these limiting factors have on the yield of various cultivars. Also, those methods for analysis of chlorophyll optical activity and/or content are appropriate for assessing the reaction of weed species to different agricultural practices (mineral nutrition, treatment by herbicides, etc. and studies of different aspects of weed ecophysiology and their influence on crop harvest.

  7. Enzyme-assisted extraction of stabilized chlorophyll from spinach.

    Science.gov (United States)

    Özkan, Gülay; Ersus Bilek, Seda

    2015-06-01

    Zinc complex formation with chlorophyll derivatives in spinach pulp was studied by adding 300ppm Zn(2+) for production of stable food colorant, followed by the heating at 110°C for 15min. Zinc complex formation increased at pH values of 7.0 or greater. Pectinex Ultra SP-L was selected for enzyme-assisted release of zinc-chlorophyll derivatives from spinach pulp. Effect of enzyme concentration (1-9%), treatment temperature (30-60°C), and time (30-210min) on total chlorophyll content (TCC) were optimized using response surface methodology. A quadratic regression model (R(2)=0.9486) was obtained from the experimental design. Optimum treatment conditions were 8% enzyme concentration, 45°C, and 30min, which yielded a 50.747mgTCC/100g spinach pulp. Enzymatic treatment was followed by solvent extraction with ethanol at a solvent-to-sample ratio of 2.5:1 at 60°C for 45min for the highest TCC recovery. Pretreatment with enzyme and extraction in ethanol resulted in 39% increase in Zn-chlorophyll derivative yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Efficiency of chlorophyll in gross primary productivity: A proof of concept and application in crops.

    Science.gov (United States)

    Gitelson, Anatoly A; Peng, Yi; Viña, Andrés; Arkebauer, Timothy; Schepers, James S

    2016-08-20

    One of the main factors affecting vegetation productivity is absorbed light, which is largely governed by chlorophyll. In this paper, we introduce the concept of chlorophyll efficiency, representing the amount of gross primary production per unit of canopy chlorophyll content (Chl) and incident PAR. We analyzed chlorophyll efficiency in two contrasting crops (soybean and maize). Given that they have different photosynthetic pathways (C3 vs. C4), leaf structures (dicot vs. monocot) and canopy architectures (a heliotrophic leaf angle distribution vs. a spherical leaf angle distribution), they cover a large spectrum of biophysical conditions. Our results show that chlorophyll efficiency in primary productivity is highly variable and responds to various physiological and phenological conditions, and water availability. Since Chl is accessible through non-destructive, remotely sensed techniques, the use of chlorophyll efficiency for modeling and monitoring plant optimization patterns is practical at different scales (e.g., leaf, canopy) and under widely-varying environmental conditions. Through this analysis, we directly related a functional characteristic, gross primary production with a structural characteristic, canopy chlorophyll content. Understanding the efficiency of the structural characteristic is of great interest as it allows explaining functional components of the plant system. Copyright © 2016 Elsevier GmbH. All rights reserved.

  9. Chlorophyll and carbohydrates in Arachis pintoi plants under influence of water regimes and nitrogen fertilization

    Directory of Open Access Journals (Sweden)

    Rita Manuele Porto Sales

    2013-06-01

    Full Text Available In this experiment the chlorophyll and carbohydrate contents of Arachis pintoi were evaluated to verify if the presence of nitrogen in the soil could contribute to the effectiveness of the establishment of this legume. The design was completely randomized, in a 4 × 4 factorial arrangement, with four N rates (0, 40, 80 and 120 kg ha-1 and four irrigation levels (25, 50, 75 and 100% of field capacity, with four replications. The biochemical evaluations of chlorophylls a and b and total chlorophyll and total soluble sugars, sucrose and starch were performed. The highest contents of chlorophyll a and b and total chlorophyll in leaves were found at the dose of 120 kg ha-1. The water regime of 25% of field capacity was responsible for the lowest content of reducing sugars and total soluble sugars in leaves, stolons and roots. In the roots, the sucrose contents were higher in these conditions, which can be associated with a slight tolerance of the plant to water stress. The water deficiency was responsible for the decrease of reducing sugars and total N in the whole plant and positively influenced the levels of chlorophyll and sugars in the stolon, promoting growth, especially of shoots, at the beginning of establishment.

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

    International Nuclear Information System (INIS)

    Ralph, P.J.; Burchett, M.D.

    1998-01-01

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

  11. Species-specific interactions between algal endosymbionts and coral hosts define their bleaching response to heat and light stress

    DEFF Research Database (Denmark)

    Abrego, David; Ulstrup, Karin E; Willis, Bette L

    2008-01-01

    The impacts of warming seas on the frequency and severity of bleaching events are well documented, but the potential for different Symbiodinium types to enhance the physiological tolerance of reef corals is not well understood. Here we compare the functionality and physiological properties...... and a potential role for host factors in determining the physiological performance of reef corals....... of juvenile corals when experimentally infected with one of two homologous Symbiodinium types and exposed to combined heat and light stress. A suite of physiological indicators including chlorophyll a fluorescence, oxygen production and respiration, as well as pigment concentration consistently demonstrated...

  12. Cryobiology of coral fragments.

    Science.gov (United States)

    Hagedorn, Mary; Farrell, Ann; Carter, Virginia L

    2013-02-01

    Around the world, coral reefs are dying due to human influences, and saving habitat alone may not stop this destruction. This investigation focused on the biological processes that will provide the first steps in understanding the cryobiology of whole coral fragments. Coral fragments are a partnership of coral tissue and endosymbiotic algae, Symbiodinium sp., commonly called zooxanthellae. These data reflected their separate sensitivities to chilling and a cryoprotectant (dimethyl sulfoxide) for the coral Pocillopora damicornis, as measured by tissue loss and Pulse Amplitude Modulated fluorometry 3weeks post-treatment. Five cryoprotectant treatments maintained the viability of the coral tissue and zooxanthellae at control values (1M dimethyl sulfoxide at 1.0, 1.5 and 2.0h exposures, and 1.5M dimethyl sulfoxide at 1.0 and 1.5h exposures, P>0.05, ANOVA), whereas 2M concentrations did not (Pzooxanthellae. During the winter when the fragments were chilled, the coral tissue remained relatively intact (∼25% loss) post-treatment, but the zooxanthellae numbers in the tissue declined after 5min of chilling (Pzooxanthellae numbers declined in response to chilling alone (P0.05, ANOVA), but it did not protect against the loss of zooxanthellae (Pzooxanthellae are the most sensitive element in the coral fragment complex and future cryopreservation protocols must be guided by their greater sensitivity. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Coral mortality in reefs: The cause and effect; A central concern for reef monitoring

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.

    stream_size 4 stream_content_type text/plain stream_name Region_Workshop_Conserv_Sustain_Mgmt_Coral_Reefs_1997_C83.pdf.txt stream_source_info Region_Workshop_Conserv_Sustain_Mgmt_Coral_Reefs_1997_C83.pdf.txt Content-Encoding ISO-8859...

  14. Coral Reefs: Beyond Mortality?

    Directory of Open Access Journals (Sweden)

    Charles Sheppard

    2000-01-01

    Full Text Available The scale of the collapse of coral reef communities in 1998 following a warming episode (Wilkinson, 2000 was unprecedented, and took many people by surprise. The Indian Ocean was the worst affected with a coral mortality over 75% in many areas such as the Chagos Archipelago (Sheppard, 1999, Seychelles (Spencer et al., 2000 and Maldives (McClanahan, 2000. Several other locations were affected at least as much, with mortality reaching 100% (to the nearest whole number; this is being compiled by various authors (e.g., CORDIO, in press. For example, in the Arabian Gulf, coral mortality is almost total across many large areas of shallow water (Sheppard, unpublished; D. George and D. John, personal communication. The mortality is patchy of course, depending on currents, location inside or outside lagoons, etc., but it is now possible to swim for over 200 m and see not one remaining living coral or soft coral on some previously rich reefs.

  15. Short-term coral bleaching is not recorded by skeletal boron isotopes.

    Science.gov (United States)

    Schoepf, Verena; McCulloch, Malcolm T; Warner, Mark E; Levas, Stephen J; Matsui, Yohei; Aschaffenburg, Matthew D; Grottoli, Andréa G

    2014-01-01

    Coral skeletal boron isotopes have been established as a proxy for seawater pH, yet it remains unclear if and how this proxy is affected by seawater temperature. Specifically, it has never been directly tested whether coral bleaching caused by high water temperatures influences coral boron isotopes. Here we report the results from a controlled bleaching experiment conducted on the Caribbean corals Porites divaricata, Porites astreoides, and Orbicella faveolata. Stable boron (δ11B), carbon (δ13C), oxygen (δ18O) isotopes, Sr/Ca, Mg/Ca, U/Ca, and Ba/Ca ratios, as well as chlorophyll a concentrations and calcification rates were measured on coral skeletal material corresponding to the period during and immediately after the elevated temperature treatment and again after 6 weeks of recovery on the reef. We show that under these conditions, coral bleaching did not affect the boron isotopic signature in any coral species tested, despite significant changes in coral physiology. This contradicts published findings from coral cores, where significant decreases in boron isotopes were interpreted as corresponding to times of known mass bleaching events. In contrast, δ13C and δ18O exhibited major enrichment corresponding to decreases in calcification rates associated with bleaching. Sr/Ca of bleached corals did not consistently record the 1.2°C difference in seawater temperature during the bleaching treatment, or alternatively show a consistent increase due to impaired photosynthesis and calcification. Mg/Ca, U/Ca, and Ba/Ca were affected by coral bleaching in some of the coral species, but the observed patterns could not be satisfactorily explained by temperature dependence or changes in coral physiology. This demonstrates that coral boron isotopes do not record short-term bleaching events, and therefore cannot be used as a proxy for past bleaching events. The robustness of coral boron isotopes to changes in coral physiology, however, suggests that reconstruction of

  16. Coral reef connectivity within the Western Gulf of Mexico

    Science.gov (United States)

    Salas-Monreal, David; Marin-Hernandez, Mark; Salas-Perez, Jose de Jesus; Salas-de-Leon, David Alberto; Monreal-Gomez, Maria Adela; Perez-España, Horacio

    2018-03-01

    The yearlong monthly mean satellite data of the geostrophic velocities, the sea surface temperature and the chlorophyll-a values were used to elucidate any possible pathway among the different coral reef systems of the Western Gulf of Mexico (WGM). The geostrophic current velocities suggested different pathways connecting the coral reef areas. The typical coastal alongshore pathway constricted to the continental shelf, and two open ocean pathway, the first connecting the Campeche Reef System (CRS) with the Veracruz (VRS) and Tuxpan-Lobos Reef Systems (TLRS), and the second pathway connecting the Tuxpan-Lobos Reef System with the Flower Garden Reef System (FGRS). According to the pathways there should be more larvae transport from the southern Gulf of Mexico reef systems toward the FGRS than the other way. The connection from the southern Gulf of Mexico toward the FGRS took place during January, May, July, August and September (2015), while the connection from the FGRS toward the southern Gulf of Mexico reef system took place during January and February (2015), this was also suggested via model outputs. The density radio (R) was used as a first approximation to elucidate the influence of the freshwater continental discharges within the continental shelf. All coral reef areas were located where the Chlorophyll-a monthly mean values had values bellow 1 mg m- 2 with a density radio between 0 and 1, i.e. under the influence of continental discharges.

  17. Coral host transcriptomic states are correlated with Symbiodinium genotypes

    KAUST Repository

    DeSalvo, Michael K.

    2010-03-01

    A mutualistic relationship between reef-building corals and endosymbiotic dinoflagellates (Symbiodinium spp.) forms the basis for the existence of coral reefs. Genotyping tools for Symbiodinium spp. have added a new level of complexity to studies concerning cnidarian growth, nutrient acquisition, and stress. For example, the response of the coral holobiont to thermal stress is connected to the host-Symbiodinium genotypic combination, as different partnerships can have different bleaching susceptibilities. In this study, we monitored Symbiodinium physiological parameters and profiled the coral host transcriptional responses in acclimated, thermally stressed, and recovered fragments of the coral Montastraea faveolata using a custom cDNA gene expression microarray. Interestingly, gene expression was more similar among samples with the same Symbiodinium content rather than the same experimental condition. In order to discount for host-genotypic effects, we sampled fragments from a single colony of M. faveolata containing different symbiont types, and found that the host transcriptomic states grouped according to Symbiodinium genotype rather than thermal stress. As the first study that links coral host transcriptomic patterns to the clade content of their Symbiodinium community, our results provide a critical step to elucidating the molecular basis of the apparent variability seen among different coral-Symbiodinium partnerships. © 2010 Blackwell Publishing Ltd.

  18. Using X-Ray Fluorescence Technique to Quantify Metal Concentration in Coral Cores from Belize

    Science.gov (United States)

    Kingsley, C.; Bhattacharya, A.; Hangsterfer, A.; Carilli, J.; Field, D. B.

    2016-12-01

    Caribbean coral reefs are some of the most threatened marine ecosystems in the world. Research appears to suggest that environmental stressors of local origin, such as sediment run off, can reduce the resilience of these reefs to global threats such as ocean warming. Sedimentation can stunt coral growth, reduce its resilience, and it is possible that trapped material could render coral skeletons brittle (personal discussions). Material trapped in coral skeletons can provide information on the sources of particulate matter in the ocean ecosystem. Despite the importance of quantifying sources and types of materials trapped in corals, the research community is yet to fully develop techniques that allow accurate representation of trapped matter, which is potentially a major source of metal content in reef building coral skeletons. The dataset presented here explores the usefulness of X-Ray Fluorescence (XRF), a widely used tool in environmental studies (but generally not in corals), to estimate metal content in coral cores collected from four locations near Belize, with varying degrees of impact from coastal processes. The coral cores together cover a period of 1862-2006. Trace, major, and minor metal content from these cores have been well-studied using solution-based ICP-MS, providing us with the unique opportunity to test the efficacy of XRF technique in characterizing metal content in these coral cores. We have measured more than 50 metals using XRF every two millimeters along slabs removed from the middle of a coral core to characterize materials present in coral skeletons. We compared the results from XRF to solution-based ICP-MS - that involves dissolving subsamples of coral skeleton to measure metal content. Overall, it appears that the non-destructive XRF technique is a viable supplement in determining sediment and metal content in coral cores, and may be particularly helpful for assessing resistant phases such as grains of sediment that are not fully

  19. Annual coral bleaching and the long-term recovery capacity of coral.

    Science.gov (United States)

    Schoepf, Verena; Grottoli, Andréa G; Levas, Stephen J; Aschaffenburg, Matthew D; Baumann, Justin H; Matsui, Yohei; Warner, Mark E

    2015-11-22

    Mass bleaching events are predicted to occur annually later this century. Nevertheless, it remains unknown whether corals will be able to recover between annual bleaching events. Using a combined tank and field experiment, we simulated annual bleaching by exposing three Caribbean coral species (Porites divaricata, Porites astreoides and Orbicella faveolata) to elevated temperatures for 2.5 weeks in 2 consecutive years. The impact of annual bleaching stress on chlorophyll a, energy reserves, calcification, and tissue C and N isotopes was assessed immediately after the second bleaching and after both short- and long-term recovery on the reef (1.5 and 11 months, respectively). While P. divaricata and O. faveolata were able to recover from repeat bleaching within 1 year, P. astreoides experienced cumulative damage that prevented full recovery within this time frame, suggesting that repeat bleaching had diminished its recovery capacity. Specifically, P. astreoides was not able to recover protein and carbohydrate concentrations. As energy reserves promote bleaching resistance, failure to recover from annual bleaching within 1 year will likely result in the future demise of heat-sensitive coral species. © 2015 The Author(s).

  20. Annual coral bleaching and the long-term recovery capacity of coral

    Science.gov (United States)

    Schoepf, Verena; Grottoli, Andréa G.; Levas, Stephen J.; Aschaffenburg, Matthew D.; Baumann, Justin H.; Matsui, Yohei; Warner, Mark E.

    2015-01-01

    Mass bleaching events are predicted to occur annually later this century. Nevertheless, it remains unknown whether corals will be able to recover between annual bleaching events. Using a combined tank and field experiment, we simulated annual bleaching by exposing three Caribbean coral species (Porites divaricata, Porites astreoides and Orbicella faveolata) to elevated temperatures for 2.5 weeks in 2 consecutive years. The impact of annual bleaching stress on chlorophyll a, energy reserves, calcification, and tissue C and N isotopes was assessed immediately after the second bleaching and after both short- and long-term recovery on the reef (1.5 and 11 months, respectively). While P. divaricata and O. faveolata were able to recover from repeat bleaching within 1 year, P. astreoides experienced cumulative damage that prevented full recovery within this time frame, suggesting that repeat bleaching had diminished its recovery capacity. Specifically, P. astreoides was not able to recover protein and carbohydrate concentrations. As energy reserves promote bleaching resistance, failure to recover from annual bleaching within 1 year will likely result in the future demise of heat-sensitive coral species. PMID:26582020

  1. Distribution of nutrients, chlorophyll and phytoplankton primary ...

    African Journals Online (AJOL)

    Distribution of nutrients, chlorophyll and phytoplankton primary production in ... Two cruises were undertaken in the vicinity of the Cape Frio upwelling cell ... and concentrations of nitrate, phosphate, silicate, oxygen and chlorophyll a. ... Estimates of the annual primary production for each of the water bodies were calculated.

  2. Completing the Feedback Loop: The Impact of Chlorophyll Data Assimilation on the Ocean State

    Science.gov (United States)

    Borovikov, Anna; Keppenne, Christian; Kovach, Robin

    2015-01-01

    In anticipation of the integration of a full biochemical model into the next generation GMAO coupled system, an intermediate solution has been implemented to estimate the penetration depth (1Kd_PAR) of ocean radiation based on the chlorophyll concentration. The chlorophyll is modeled as a tracer with sources-sinks coming from the assimilation of MODIS chlorophyll data. Two experiments were conducted with the coupled ocean-atmosphere model. In the first, climatological values of Kpar were used. In the second, retrieved daily chlorophyll concentrations were assimilated and Kd_PAR was derived according to Morel et al (2007). No other data was assimilated to isolate the effects of the time-evolving chlorophyll field. The daily MODIS Kd_PAR product was used to validate the skill of the penetration depth estimation and the MERRA-OCEAN re-analysis was used as a benchmark to study the sensitivity of the upper ocean heat content and vertical temperature distribution to the chlorophyll input. In the experiment with daily chlorophyll data assimilation, the penetration depth was estimated more accurately, especially in the tropics. As a result, the temperature bias of the model was reduced. A notably robust albeit small (2-5 percent) improvement was found across the equatorial Pacific ocean, which is a critical region for seasonal to inter-annual prediction.

  3. Quantifying mangrove chlorophyll from high spatial resolution imagery

    NARCIS (Netherlands)

    Heenkenda, M.K.; Joyce, K.E.; Maier, S.W.; Bruin, de S.

    2015-01-01

    Lower than expected chlorophyll concentration of a plant can directly limit photosynthetic activity, and resultant primary production. Low chlorophyll concentration may also indicate plant physiological stress. Compared to other terrestrial vegetation, mangrove chlorophyll variations are poorly

  4. Non-intrusive Assessment of Photosystem II and Photosystem I in Whole Coral Tissues

    Directory of Open Access Journals (Sweden)

    Milán Szabó

    2017-08-01

    Full Text Available Reef building corals (phylum Cnidaria harbor endosymbiotic dinoflagellate algae (genus Symbiodinium that generate photosynthetic products to fuel their host's metabolism. Non-invasive techniques such as chlorophyll (Chl fluorescence analyses of Photosystem II (PSII have been widely used to estimate the photosynthetic performance of Symbiodinium in hospite. However, since the spatial origin of PSII chlorophyll fluorescence in coral tissues is uncertain, such signals give limited information on depth-integrated photosynthetic performance of the whole tissue. In contrast, detection of absorbance changes in the near infrared (NIR region integrates signals from deeper tissue layers due to weak absorption and multiple scattering of NIR light. While extensively utilized in higher plants, NIR bio-optical techniques are seldom applied to corals. We have developed a non-intrusive measurement method to examine photochemistry of intact corals, based on redox kinetics of the primary electron donor in Photosystem I (P700 and chlorophyll fluorescence kinetics (Fast-Repetition Rate fluorometry, FRRf. Since the redox state of P700 depends on the operation of both PSI and PSII, important information can be obtained on the PSII-PSI intersystem electron transfer kinetics. Under moderate, sub-lethal heat stress treatments (33°C for ~20 min, the coral Pavona decussata exhibited down-regulation of PSII electron transfer kinetics, indicated by slower rates of electron transport from QA to plastoquinone (PQ pool, and smaller relative size of oxidized PQ with concomitant decrease of a specifically-defined P700 kinetics area, which represents the active pool of PSII. The maximum quantum efficiency of PSII (Fv/Fm and functional absorption cross-section of PSII (σPSII remained unchanged. Based on the coordinated response of P700 parameters and PSII-PSI electron transport properties, we propose that simple P700 kinetics parameters as employed here serve as indicators of

  5. Impacts of turbidity on corals: The relative importance of light limitation and suspended sediments

    International Nuclear Information System (INIS)

    Bessell-Browne, Pia; Negri, Andrew P.; Fisher, Rebecca; Clode, Peta L.; Duckworth, Alan; Jones, Ross

    2017-01-01

    As part of an investigation of the effects of water quality from dredging/natural resuspension on reefs, the effects of suspended sediment concentrations (SSCs) (0, 30, 100 mg L −1 ) and light (~ 0, 1.1, 8.6 mol photons m −2 d −1 ) were examined alone and in combination, on the corals Acropora millepora, Montipora capricornis and Porites spp. over an extended (28 d) period. No effects were observed at any sediment concentrations when applied alone. All corals in the lowest light treatments lost chlorophyll a and discoloured (bleached) after a week. Coral mortality only occurred in the two lowest light treatments and was higher when simultaneously exposed to elevated SSCs. Compared to water quality data collected during large dredging programs and natural resuspension events (and in the absence of sediment deposition as a cause-effect pathway) these data suggest the light reduction associated with turbidity poses a proportionally greater risk than effects of elevated SSCs alone. - Highlights: • Exposure of corals to low light conditions results in reduced quantum yields followed by bleaching of tissue. • Suspended sediment concentrations, without a reduction in light, have no impact on coral health. • An interaction between elevated suspended sediment concentrations and reduced light result in partial mortality of corals. • Management of dredging should minimise exposure of corals to low light to avoid unnecessary stress and impacts upon health.

  6. Quantification of total and particulate dimethylsulfoniopropionate (DMSP) in five Bermudian coral species across a depth gradient

    Science.gov (United States)

    Yost, D. M.; Jones, R.; Rowe, C. L.; Mitchelmore, Carys Louise

    2012-06-01

    The symbiotic dinoflagellate microalgae of corals ( Symbiodinium spp.) contain high concentrations of dimethylsulfoniopropionate (DMSP), a multifunctional metabolite commonly found in many species of marine algae and dinoflagellates. A photoprotective antioxidant function for DMSP and its breakdown products has often been inferred in algae, but its role(s) in the coral-algal symbiosis remains elusive. To examine potential correlations between environmental and physiological parameters and DMSP, total DMSP (DMSPt, from the host coral and zooxanthellae), particulate DMSP (DMSPp, from the zooxanthellae only), coral surface area, and total protein, as well as zooxanthellae density, chlorophyll concentration, cell volume and genotype (i.e., clade) were measured in five coral species from the Diploria- Montastraea- Porites species complex in Bermuda along a depth gradient of 4, 12, 18, and 24 m. DMSPt concentrations were consistently greater than DMSPp concentrations in all species suggesting the possible translocation of DMSP from symbiont to host. D. labyrinthiformis was notably different from the other corals examined, showing DMSPp and DMSPt increases (per coral surface area or tissue biomass) with increasing water depth. However, overall, there were no consistent depth-related patterns in DMSPp and DMSPt concentrations. Further research, investigating dimethylsulfide (DMS), dimethylsulfoxide, and acrylate levels and DMSP-lyase activity in correlation with other biomarker endpoints that have been shown to be depth (i.e., temperature and light) responsive are needed to substantiate the significance of these findings.

  7. Photosynthesis, light use efficiency, and yield of reduced-chlorophyll soybean mutants in field conditions

    Science.gov (United States)

    Reducing chlorophyll (chl) content may improve the conversion efficiency of absorbed radiation into biomass (ec) and therefore yield in dense monoculture crops by improving light penetration and distribution within the canopy. Modeling suggests that reducing chl content may also reduce leaf temperat...

  8. Chlorophyll Synthase under Epigenetic Surveillance Is Critical for Vitamin E Synthesis, and Altered Expression Affects Tocopherol Levels in Arabidopsis.

    Science.gov (United States)

    Zhang, Chunyu; Zhang, Wei; Ren, Guodong; Li, Delin; Cahoon, Rebecca E; Chen, Ming; Zhou, Yongming; Yu, Bin; Cahoon, Edgar B

    2015-08-01

    Chlorophyll synthase catalyzes the final step in chlorophyll biosynthesis: the esterification of chlorophyllide with either geranylgeranyl diphosphate or phytyl diphosphate (PDP). Recent studies have pointed to the involvement of chlorophyll-linked reduction of geranylgeranyl by geranylgeranyl reductase as a major pathway for the synthesis of the PDP precursor of tocopherols. This indirect pathway of PDP synthesis suggests a key role of chlorophyll synthase in tocopherol production to generate the geranylgeranyl-chlorophyll substrate for geranylgeranyl reductase. In this study, contributions of chlorophyll synthase to tocopherol formation in Arabidopsis (Arabidopsis thaliana) were explored by disrupting and altering expression of the corresponding gene CHLOROPHYLL SYNTHASE (CHLSYN; At3g51820). Leaves from the homozygous chlysyn1-1 null mutant were nearly devoid of tocopherols, whereas seeds contained only approximately 25% of wild-type tocopherol levels. Leaves of RNA interference lines with partial suppression of CHLSYN displayed marked reductions in chlorophyll but up to a 2-fold increase in tocopherol concentrations. Cauliflower mosaic virus35S-mediated overexpression of CHLSYN unexpectedly caused a cosuppression phenotype at high frequencies accompanied by strongly reduced chlorophyll content and increased tocopherol levels. This phenotype and the associated detection of CHLSYN-derived small interfering RNAs were reversed with CHLSYN overexpression in rna-directed rna polymerase6 (rdr6), which is defective in RNA-dependent RNA polymerase6, a key enzyme in sense transgene-induced small interfering RNA production. CHLSYN overexpression in rdr6 had little effect on chlorophyll content but resulted in up to a 30% reduction in tocopherol levels in leaves. These findings show that altered CHLSYN expression impacts tocopherol levels and also, show a strong epigenetic surveillance of CHLSYN to control chlorophyll and tocopherol synthesis. © 2015 American Society of

  9. TRACKING CHANGES IN CHLOROPHYLL AND CAROTENOIDS IN THE PRODUCTION PROCESS OF FROZEN SPINACH PURÉE

    Directory of Open Access Journals (Sweden)

    Andrea Mendelová

    2014-02-01

    Full Text Available Spinach is in the professional and general public considered highly nutritious vegetable with many beneficial effects on human health. It is a rich source of antioxidant active substances, especially chlorophyll, carotenoids, flavonoids and minerals especially zinc and copper. This work studies the changes of chlorophyll and carotenoids that occur after mass production technology of freezing at -37 °C. Before freezing was used blanching operation. In this work we used a variety Boeing, Boa, Beaver, Hudson and Chica. The highest content of all monitored parameters are found in fresh leaves of sampled Hudson. We found that within the processing decreases chlorophyll in 16.6%, 13.8% of chlorophyll b and carotenoids of 6.15%. This decrease was in all cases statistically significant.

  10. Coral Reef Guidance

    Science.gov (United States)

    Guidance prepared by EPA and Army Corps of Engineers concerning coral reef protection under the Clean Water Act, Marine Protection, Research, and Sanctuaries Act, Rivers and Harbors Act, and Federal Project Authorities.

  11. All Framing Corals

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted habitat suitability for several taxa of deep-sea corals. Predictions were modeled using a statistical machine-learning algorithm called...

  12. Corals and Sclerosponges

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past climate and ocean environment derived from stable isotope, trace metal, and other measurements made on corals and sclerosponges. Parameter keywords...

  13. BOREAS TE-9 NSA Leaf Chlorophyll Density

    Science.gov (United States)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Margolis, Hank; Sy, Mikailou

    2000-01-01

    The BOREAS TE-9 team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. These data were collected to help provide an explanation of potential seasonal and spatial changes of leaf pigment properties in boreal forest species at the NSA. At different dates (FFC-Winter, FFC-Thaw, IFC-1, IFC-2, and IMC-3), foliage samples were collected from the upper third of the canopy for five NSA sites (YJP, OJP, OBS, UBS, and OA) near Thompson, Manitoba. Subsamples of 100 needles for black spruce, 20 needles for jack pine, and single leaf for trembling aspen were cut into pieces and immersed in a 20-mL DMF aliquot in a Nalgene test tube. The extracted foliage materials were then oven-dried at 68 C for 48 hours and weighed. Extracted leaf dry weight was converted to a total leaf area basis to express the chlorophyll content in mg/sq cm of total leaf area. The data are provided in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  14. Occurrence of thraustochytrid fungi in corals and coral mucus

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, S.; Balasubramanian

    Occurrence of thraustochytrid fungi in corals, fresh coral mucus and floating and attached mucus detritus from the Lakshadweep Islands in the Arabian Sea was studied. Corallochytrium limacisporum Raghukumar, Thraustochytrium motivum Goldstein...

  15. The effects of habitat on coral bleaching responses in Kenya.

    Science.gov (United States)

    Grimsditch, Gabriel; Mwaura, Jelvas M; Kilonzo, Joseph; Amiyo, Nassir

    2010-06-01

    This study examines the bleaching responses of scleractinian corals at four sites in Kenya (Kanamai, Vipingo, Mombasa and Nyali) representing two distinct lagoon habitats (relatively shallow and relatively deep). Bleaching incidence was monitored for the whole coral community, while zooxanthellae densities and chlorophyll levels were monitored for target species (Pocillopora damicornis, Porites lutea, and Porites cylindrica) during a non-bleaching year (2006) and a year of mild-bleaching (2007). Differences in bleaching responses between habitats were observed, with shallower sites Kanamai and Vipingo exhibiting lower bleaching incidence than deeper sites Nyali and Mombasa. These shallower lagoons display more fluctuating thermal and light environments than the deeper sites, suggesting that corals in the shallower lagoons have acclimatized and/or adapted to the fluctuating environmental conditions they endure on a daily basis and have become more resistant to bleaching stress. In deeper sites that did exhibit higher bleaching (Mombasa and Nyali), it was found that coral recovery occurred more quickly in the protected area than in the non-protected area.

  16. Carbon and nitrogen isotopic analysis of coral-associated nitrogen in rugose corals of the Middle Devonian, implications for paleoecology and paleoceanography.

    Science.gov (United States)

    Hickey, A. N.; Junium, C. K.; Uveges, B. T.; Ivany, L. C.; Martindale, R. C.

    2017-12-01

    The Middle Devonian Appalachian Basin of Central New York hosts an extraordinary diversity of well-studied fossil invertebrates within the shallow marine sequences of the Givetian Age, Hamilton Group. Of particular interest are a series of aerially expansive coral beds with diverse assemblages of rugose corals. These well-preserved specimens provide an excellent opportunity to test the feasibility of δ15N and δ13C analyses in rugose corals in an effort to resolve outstanding issues regarding their paleoecology and ontogeny as well environmental dynamics within the Devonian Appalachian Basin. Here we present carbon and nitrogen isotope analyses of the rugose corals Heliophyllum and Siphonophrentis from the Joshua Coral Bed. Corals were cleaned of the host calcareous shale and sonicated sequentially in deionized water and methanol, and then oxidatively cleaned. Cleaned corals were sectioned into 0.5cm billets to obtain enough residual organic material for analysis. The organic content of the corals is low, but nanoEA allows for serial sampling of 5-10 samples per coral. Coral sections were decarbonated and the residual organic material is filtered and dried prior to analysis. Coral organic matter is analyzed in triplicate using nanoEA, which is a cryo-trapping, capillary focusing technique for δ15N and δ13C. The δ15N of organic matter extracted from rugose corals is, on average, enriched by 2-4‰ relative to the bulk nitrogen in the host rock. As well, the δ13C of organic carbon from the corals is 13C-enriched relative to the bulk rock, but to a lesser degree (no more than 1.5‰). Assuming that the bulk rock carbon and nitrogen are largely representative of the long-term primary production background, the modest enrichment is consistent with a trophic effect, and that rugose corals are likely planktivores. In an individual coral, δ15N ranges by 3-4‰ over its length, and when adjusted for trophic enrichment varies around the average δ15N of bulk

  17. Radiation induced chlorophyll mutations in rice

    International Nuclear Information System (INIS)

    Bari, G.; Mustafa, G.; Soomro, A.M.; Baloch, A.W.

    1985-01-01

    Air dried grains of four local varieties of rice were treated with gamma-rays and fast neutrons for determining their mutagenic effectiveness through the occurence of chlorophyll mutations. Fast neutrons were more effective in inducing chlorophyll mutations and the rice variety Basmati 370 produced maximum number of mutations followed by varieties Sonahri Sugdasi, Jajai 77 and Sada Gulab. The highest frequency of chlorophyll mutations was that of albina types followed by striata types. The xantha, viridis and tigrina types of mutations were less frequent. (authors)

  18. Lettuce flavonoids screening and phenotyping by chlorophyll fluorescence excitation ratio.

    Science.gov (United States)

    Zivcak, Marek; Brückova, Klaudia; Sytar, Oksana; Brestic, Marian; Olsovska, Katarina; Allakhverdiev, Suleyman I

    2017-06-01

    Environmentally induced variation and the genotypic differences in flavonoid and phenolic content in lettuce can be reliably detected using the appropriate parameters derived from the records of rapid non-invasive fluorescence technique. The chlorophyll fluorescence excitation ratio method was designed as a rapid and non-invasive tool to estimate the content of UV-absorbing phenolic compounds in plants. Using this technique, we have assessed the dynamics of accumulation of flavonoids related to developmental changes and environmental effects. Moreover, we have tested appropriateness of the method to identify the genotypic differences and fluctuations in total phenolics and flavonoid content in lettuce. Six green and two red genotypes of lettuce (Lactuca sativa L.) grown in pots were exposed to two different environments for 50 days: direct sunlight (UV-exposed) and greenhouse conditions (low UV). The indices based on the measurements of chlorophyll fluorescence after red, green and UV excitation indicated increase of the content of UV-absorbing compounds and anthocyanins in the epidermis of lettuce leaves. In similar, the biochemical analyses performed at the end of the experiment confirmed significantly higher total phenolic and flavonoid content in lettuce plants exposed to direct sun compared to greenhouse conditions and in red compared to green genotypes. As the correlation between the standard fluorescence indices and the biochemical records was negatively influenced by the presence of red genotypes, we proposed the use of a new parameter named Modified Flavonoid Index (MFI) taking into an account both absorbance changes due to flavonol and anthocyanin content, for which the correlation with flavonoid and phenolic content was relatively good. Thus, our results confirmed that the fluorescence excitation ratio method is useful for identifying the major differences in phenolic and flavonoid content in lettuce plants and it can be used for high-throughput pre

  19. Osmoadjustment in the Coral Holobiont

    KAUST Repository

    Rö thig, Till

    2017-01-01

    and amino acids to be putatively involved in the osmoadjustment. Importantly, under high salinity the osmolyte floridoside was consistently increased. This could be corroborated in the coral model Aiptasia and in corals from the Persian/Arabian Gulf, where

  20. Seasonal Composite Chlorophyll Concentrations - Gulf of Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are seasonal composites, and were calculated...

  1. EmpiricalValues_Chlorophyll_GrandComposite

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are a composite of several years (1997-2005)...

  2. Monthly Composite Chlorophyll Concentrations - Gulf of Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are monthly composites, and were calculated...

  3. Using visible reflectance spectroscopy to reconstruct historical changes in chlorophyll a concentration in East Antarctic ponds

    Directory of Open Access Journals (Sweden)

    Qianqian Chen

    2013-12-01

    Full Text Available The visible reflectance spectroscopy (VRS and chlorophyll a concentration were determined in three sediment profiles collected from East Antarctica to investigate the potential application of VRS in reconstructing historical changes in Antarctic lake primary productivity. The results showed that the appearance of a trough at 650–700 nm is an important marker for chlorophyll a concentration and can therefore be used to distinguish the sedimentary organic matter source from guano and algae. The measured chlorophyll a content had significant positive correlations with the trough area between 650 and 700 nm, and no distinct trough was found in the sediments with organic matter completely derived from guano. Modelling results showed that the spectra spectrally inferred chlorophyll a content, and the measured data exhibit consistent trends with depth, showing that the dimensionless trough area can serve as an independent proxy for reconstructing historical fluctuations in the primary production of Antarctic ponds. The correlation of phosphorus (P with measured and inferred chlorophyll a contents in ornithogenic sediments near penguin colonies indicates that the change in primary productivity in the Antarctic ponds investigated was closely related to the amount of guano input from these birds.

  4. Induction of chlorophyll chimeras and chlorophyll mutations in mungbean (Vigna radiata) cv. T44

    International Nuclear Information System (INIS)

    Singh, V.P.; Yadav, R.D.S.

    1993-01-01

    Uniform and healthy seeds of mungbean (Vigna radiata) cv. T44 were exposed to varying doses of gamma rays, ethyl methane sulphonate (EMS) and combination treatment of gamma rays with EMS. The data were recorded for seed germination, plant survival, frequency and spectrum of chlorophyll chimeras in M 1 and chlorophyll mutations in M 2 generation. Among all, the combination treatments were found most effective for inducing chlorophyll chimeras and chlorophyll mutations than the gamma rays or EMS alone. Of the mutants under reference, the albino, xantha and chlorina showed monogenic recessive while viridis exhibited digenic recessive inheritance. (author). 8 refs., 2 tabs

  5. Organization of chlorophyll biosynthesis and insertion of chlorophyll into the chlorophyll-binding proteins in chloroplasts.

    Science.gov (United States)

    Wang, Peng; Grimm, Bernhard

    2015-12-01

    Oxygenic photosynthesis requires chlorophyll (Chl) for the absorption of light energy, and charge separation in the reaction center of photosystem I and II, to feed electrons into the photosynthetic electron transfer chain. Chl is bound to different Chl-binding proteins assembled in the core complexes of the two photosystems and their peripheral light-harvesting antenna complexes. The structure of the photosynthetic protein complexes has been elucidated, but mechanisms of their biogenesis are in most instances unknown. These processes involve not only the assembly of interacting proteins, but also the functional integration of pigments and other cofactors. As a precondition for the association of Chl with the Chl-binding proteins in both photosystems, the synthesis of the apoproteins is synchronized with Chl biosynthesis. This review aims to summarize the present knowledge on the posttranslational organization of Chl biosynthesis and current attempts to envision the proceedings of the successive synthesis and integration of Chl into Chl-binding proteins in the thylakoid membrane. Potential auxiliary factors, contributing to the control and organization of Chl biosynthesis and the association of Chl with the Chl-binding proteins during their integration into photosynthetic complexes, are discussed in this review.

  6. Mediterranean Ocean Colour Chlorophyll Trends.

    Science.gov (United States)

    Colella, Simone; Falcini, Federico; Rinaldi, Eleonora; Sammartino, Michela; Santoleri, Rosalia

    2016-01-01

    In being at the base of the marine food web, phytoplankton is particularly important for marine ecosystem functioning (e.g., biodiversity). Strong anthropization, over-exploitation of natural resources, and climate change affect the natural amount of phytoplankton and, therefore, represent a continuous threat to the biodiversity in marine waters. In particular, a concerning risks for coastal waters is the increase in nutrient inputs of terrestrial/anthropogenic origin that can lead to undesirable modifications of phytoplankton concentration (i.e., eutrophication). Monitoring chlorophyll (Chl) concentration, which is a proxy of phytoplankton biomass, is an efficient tool for recording and understanding the response of the marine ecosystem to human pressures and thus for detecting eutrophication. Here, we compute Chl trends over the Mediterranean Sea by using satellite data, also highlighting the fact that remote sensing may represent an efficient and reliable solution to synoptically control the "good environmental status" (i.e., the Marine Directive to achieve Good Environmental Status of EU marine waters by 2020) and to assess the application of international regulations and environmental directives. Our methodology includes the use of an ad hoc regional (i.e., Mediterranean) algorithm for Chl concentration retrieval, also accounting for the difference between offshore (i.e., Case I) and coastal (i.e., Case II) waters. We apply the Mann-Kendall test and the Sens's method for trend estimation to the Chl concentration de-seasonalized monthly time series, as obtained from the X-11 technique. We also provide a preliminary analysis of some particular trends by evaluating their associated inter-annual variability. The high spatial resolution of our approach allows a clear identification of intense trends in those coastal waters that are affected by river outflows. We do not attempt to attribute the observed trends to specific anthropogenic events. However, the trends

  7. Mediterranean Ocean Colour Chlorophyll Trends.

    Directory of Open Access Journals (Sweden)

    Simone Colella

    Full Text Available In being at the base of the marine food web, phytoplankton is particularly important for marine ecosystem functioning (e.g., biodiversity. Strong anthropization, over-exploitation of natural resources, and climate change affect the natural amount of phytoplankton and, therefore, represent a continuous threat to the biodiversity in marine waters. In particular, a concerning risks for coastal waters is the increase in nutrient inputs of terrestrial/anthropogenic origin that can lead to undesirable modifications of phytoplankton concentration (i.e., eutrophication. Monitoring chlorophyll (Chl concentration, which is a proxy of phytoplankton biomass, is an efficient tool for recording and understanding the response of the marine ecosystem to human pressures and thus for detecting eutrophication. Here, we compute Chl trends over the Mediterranean Sea by using satellite data, also highlighting the fact that remote sensing may represent an efficient and reliable solution to synoptically control the "good environmental status" (i.e., the Marine Directive to achieve Good Environmental Status of EU marine waters by 2020 and to assess the application of international regulations and environmental directives. Our methodology includes the use of an ad hoc regional (i.e., Mediterranean algorithm for Chl concentration retrieval, also accounting for the difference between offshore (i.e., Case I and coastal (i.e., Case II waters. We apply the Mann-Kendall test and the Sens's method for trend estimation to the Chl concentration de-seasonalized monthly time series, as obtained from the X-11 technique. We also provide a preliminary analysis of some particular trends by evaluating their associated inter-annual variability. The high spatial resolution of our approach allows a clear identification of intense trends in those coastal waters that are affected by river outflows. We do not attempt to attribute the observed trends to specific anthropogenic events. However

  8. Role of chlorophylls, amino acids and sugars in tea

    International Nuclear Information System (INIS)

    Dev Choudhury, M.N.

    1980-01-01

    Plucked tea shoots from clones of different varieties of tea were withered, rolled, fermented and fired by CTC and orthodox methods of manufacture. Quantitative changes in the levels of chlorophylls, amino acids and water soluble sugars during different stages of processing of tea and also changes in the contents of their degradation products were studied by feeding 14 C-labelled phenylalanine, glucose, sodium carbonate and sodium propionate to the excised shoots and subsequently analysing the products. Results are discussed and suggestions have been made about adjusting the conditions of manufacture so that the teas with desired chemical constituents are produced. (M.G.B.)

  9. Coral mucus functions as an energy carrier and particle trap in the reef ecosystem

    DEFF Research Database (Denmark)

    Wild, C.; Huettel, M.; Klueter, A.

    2004-01-01

    Zooxanthellae, endosymbiotic algae of reef-building corals, substantially contribute to the high gross primary production of coral reefs(1), but corals exude up to half of the carbon assimilated by their zooxanthellae as mucus(2,3). Here we show that released coral mucus efficiently traps organic...... matter from the water column and rapidly carries energy and nutrients to the reef lagoon sediment, which acts as a biocatalytic mineralizing filter. In the Great Barrier Reef, the dominant genus of hard corals, Acropora, exudes up to 4.8 litres of mucus per square metre of reef area per day. Between 56......% and 80% of this mucus dissolves in the reef water, which is filtered through the lagoon sands. Here, coral mucus is degraded at a turnover rate of at least 7% per hour. Detached undissolved mucus traps suspended particles, increasing its initial organic carbon and nitrogen content by three orders...

  10. Genetic Analysis and Molecular Mapping of a Novel Chlorophyll-Deficit Mutant Gene in Rice

    Directory of Open Access Journals (Sweden)

    Xiao-qun HUANG

    2008-03-01

    Full Text Available A rice etiolation mutant 824ys featured with chlorophyll deficiency was identified from a normal green rice variety 824B. It showed whole green-yellow plant from the seedling stage, reduced number of tillers and longer growth duration. The contents of chlorophyll, chlorophyll a, chlorophyll b and net photosynthetic rate in leaves of the mutant obviously decreased, as well as the number of spikelets per panicle, seed setting rate and 1000-grain weight compared with its wild-type parent. Genetic analyses on F1 and F2 generations of 824ys crossed with three normal green varieties showed that the chlorophyll-deficit mutant character was controlled by a pair of recessive nuclear gene. Genetic mapping of the mutant gene was conducted by using microsatellite markers and F2 mapping population of 495R/824ys, and the mutant gene of 824ys was mapped on the short arm of rice chromosome 3. The genetic distances from the target gene to the markers RM218, RM282 and RM6959 were 25.6 cM, 5.2 cM and 21.8 cM, respectively. It was considered to be a new chlorophyll-deficit mutant gene and tentatively named as chl11(t.

  11. Spatial-temporal variability of leaf chlorophyll and its relationship with cocoa yield

    Directory of Open Access Journals (Sweden)

    Caique C. Medauar

    Full Text Available ABSTRACT The objective of this study was to evaluate the spatial-temporal variability of leaf chlorophyll index and its relationship with cocoa yield. The experiment was carried out in an experimental area of cocoa production located in Ilhéus, Bahia State, Brazil. Leaf chlorophyll content was measured in September, October, January, February, March and April in the 2014/2015 season, at each sampling point of a regular grid by using a portable chlorophyll meter. Under the same conditions, yield was evaluated and the data were submitted to descriptive statistics and a linear correlation study. Geostatistical analysis was used to determine and quantify the spatial and temporal variability of leaf chlorophyll index and yield. Leaf chlorophyll index varied over the period evaluated, but the months of February, March and April showed no spatial dependence in the study area, indicating absence of temporal stability. Cocoa monthly yield, except in January, presented high spatial variability. Under the conditions of this study, it was not possible to establish a relationship between leaf chlorophyll index and cocoa yield.

  12. Assessing the ecological effects of human impacts on coral reefs in Bocas del Toro, Panama.

    Science.gov (United States)

    Seemann, Janina; González, Cindy T; Carballo-Bolaños, Rodrigo; Berry, Kathryn; Heiss, Georg A; Struck, Ulrich; Leinfelder, Reinhold R

    2014-03-01

    Environmental and biological reef monitoring was conducted in Almirante Bay (Bahía Almirante) in Bocas del Toro, Panama, to assess impacts from anthropogenic developments. An integrated monitoring investigated how seasonal temperature stress, turbidity, eutrophication and physical impacts threatened reef health and biodiversity throughout the region. Environmental parameters such as total suspended solids [TSS], carbon isotopes (δ(13)C), C/N ratios, chlorophyll a, irradiance, secchi depth, size fractions of the sediments and isotope composition of dissolved inorganic carbon [DIC] of the water were measured throughout the years 2010 and 2011 and were analysed in order to identify different impact sources. Compared to data from Collin et al. (Smithsonian Contributions to the Marine Sciences 38:324-334, 2009) chlorophyll a has doubled at sites close to the city and the port Almirante (from 0.46-0.49 to 0.78-0.97 μg l(-1)) and suspension load increased, visible by a decrease in secchi depth values. Visibility decreased from 9-13 m down to 4 m at the bay inlet Boca del Drago, which is strongly exposed to river run off and dredging for the shipping traffic. Eutrophication and turbidity levels seemed to be the determining factor for the loss of hard coral diversity, most significant at chlorophyll a levels higher than 0.5 μg l(-1) and TSS levels higher than 4.7 mg l(-1). Hard coral cover within the bay has also declined, at some sites down to turbidity and eutrophication compared to other hard coral species in the bay. Serious overfishing was detected in the region by a lack of adult and carnivorous fish species, such as grunts, snappers and groupers. Study sites less impacted by anthropogenic activities and/or those with local protection showed a higher hard coral cover and fish abundance; however, an overall loss of hard coral diversity was observed.

  13. Genetic dissection of chlorophyll content at different growth stages in ...

    Indian Academy of Sciences (India)

    57 were registered by Henan in 2006 (Hai and Kang 2007) and by state (China) ... autumn of 2006, the lines were grown in a plot with four 2-m rows spaced 25 ..... 1255–1264. Wang F. H., Wang G. X., Li X. Y., Huang J. L. and Zheng J. K. 2008.

  14. Influence of vermicompost humic acid on chlorophyll content and ...

    African Journals Online (AJOL)

    S

    2016-11-23

    Nov 23, 2016 ... cattle used was fed mainly with grasses, and the manure was processed with African red worm. This vermicompost was used for the humic substances extraction according to International humic substances society (2008) with NaOH (0.1 mol L-1) in a proportion of 1:10 (mg of vermicompost: mL dissolution) ...

  15. Coral physiology and microbiome dynamics under combined warming and ocean acidification.

    Directory of Open Access Journals (Sweden)

    Andréa G Grottoli

    Full Text Available Rising seawater temperature and ocean acidification threaten the survival of coral reefs. The relationship between coral physiology and its microbiome may reveal why some corals are more resilient to these global change conditions. Here, we conducted the first experiment to simultaneously investigate changes in the coral microbiome and coral physiology in response to the dual stress of elevated seawater temperature and ocean acidification expected by the end of this century. Two species of corals, Acropora millepora containing the thermally sensitive endosymbiont C21a and Turbinaria reniformis containing the thermally tolerant endosymbiont Symbiodinium trenchi, were exposed to control (26.5°C and pCO2 of 364 μatm and treatment (29.0°C and pCO2 of 750 μatm conditions for 24 days, after which we measured the microbial community composition. These microbial findings were interpreted within the context of previously published physiological measurements from the exact same corals in this study (calcification, organic carbon flux, ratio of photosynthesis to respiration, photosystem II maximal efficiency, total lipids, soluble animal protein, soluble animal carbohydrates, soluble algal protein, soluble algal carbohydrate, biomass, endosymbiotic algal density, and chlorophyll a. Overall, dually stressed A. millepora had reduced microbial diversity, experienced large changes in microbial community composition, and experienced dramatic physiological declines in calcification, photosystem II maximal efficiency, and algal carbohydrates. In contrast, the dually stressed coral T. reniformis experienced a stable and more diverse microbiome community with minimal physiological decline, coupled with very high total energy reserves and particulate organic carbon release rates. Thus, the microbiome changed and microbial diversity decreased in the physiologically sensitive coral with the thermally sensitive endosymbiotic algae but not in the physiologically

  16. Coral physiology and microbiome dynamics under combined warming and ocean acidification.

    Science.gov (United States)

    Grottoli, Andréa G; Dalcin Martins, Paula; Wilkins, Michael J; Johnston, Michael D; Warner, Mark E; Cai, Wei-Jun; Melman, Todd F; Hoadley, Kenneth D; Pettay, D Tye; Levas, Stephen; Schoepf, Verena

    2018-01-01

    Rising seawater temperature and ocean acidification threaten the survival of coral reefs. The relationship between coral physiology and its microbiome may reveal why some corals are more resilient to these global change conditions. Here, we conducted the first experiment to simultaneously investigate changes in the coral microbiome and coral physiology in response to the dual stress of elevated seawater temperature and ocean acidification expected by the end of this century. Two species of corals, Acropora millepora containing the thermally sensitive endosymbiont C21a and Turbinaria reniformis containing the thermally tolerant endosymbiont Symbiodinium trenchi, were exposed to control (26.5°C and pCO2 of 364 μatm) and treatment (29.0°C and pCO2 of 750 μatm) conditions for 24 days, after which we measured the microbial community composition. These microbial findings were interpreted within the context of previously published physiological measurements from the exact same corals in this study (calcification, organic carbon flux, ratio of photosynthesis to respiration, photosystem II maximal efficiency, total lipids, soluble animal protein, soluble animal carbohydrates, soluble algal protein, soluble algal carbohydrate, biomass, endosymbiotic algal density, and chlorophyll a). Overall, dually stressed A. millepora had reduced microbial diversity, experienced large changes in microbial community composition, and experienced dramatic physiological declines in calcification, photosystem II maximal efficiency, and algal carbohydrates. In contrast, the dually stressed coral T. reniformis experienced a stable and more diverse microbiome community with minimal physiological decline, coupled with very high total energy reserves and particulate organic carbon release rates. Thus, the microbiome changed and microbial diversity decreased in the physiologically sensitive coral with the thermally sensitive endosymbiotic algae but not in the physiologically tolerant coral with

  17. Light induced intraspecific variability in response to thermal stress in the hard coral Stylophora pistillata

    Directory of Open Access Journals (Sweden)

    Arjen Tilstra

    2017-10-01

    Full Text Available Recent research suggests that prior exposure of several months to elevated irradiance induces enhanced thermal tolerance in scleractinian corals. While this tolerance has been reported at the species level, individual coral colonies may react differently due to individual variability in thermal tolerance. As thermal anomalies are predicted to become common in the upcoming future, intraspecific variation may be key to the survival of coral populations. In order to study light-history based thermal stress responses on individual colonies, we developed a preliminary microcosm experiment where three randomly chosen, aquacultured colonies of the model coral Stylophora pistillata were exposed to two irradiance treatments (200 and 400 μmol photons m−2 s−1 for 31 days, followed by artificially induced heat stress (∼33.4 °C. We found different responses to occur at both the intraspecific and the intracolonial levels, as indicated by either equal, less severe, delayed, and/or even non-necrotic responses of corals previously exposed to the irradiance of 400 compared to 200 μmol photons m−2 s−1. In addition, all individual colonies revealed light-enhanced calcification. Finally, elevated irradiance resulted in a lower chlorophyll a concentration in one colony compared to the control treatment, and the same colony displayed more rapid bleaching compared to the other ones. Taken together, this study highlights the potential importance of intra-individual variability in physiological responses of scleractinian corals and provides recommendations for improving methodological designs for future studies.

  18. Mesoscale variation in the photophysiology of the reef building coral Pocillopora damicornis along an environmental gradient

    Science.gov (United States)

    Cooper, Timothy F.; Ulstrup, Karin E.

    2009-06-01

    Spatial variation in the photophysiology of symbiotic dinoflagellates (zooxanthellae) of the scleractinian coral Pocillopora damicornis was examined along an environmental gradient in the Whitsunday Islands (Great Barrier Reef) at two depths (3 m and 6 m). Chlorophyll a fluorescence of photosystem II (PSII) and PAR-absorptivity measurements were conducted using an Imaging-PAM (pulse-amplitude-modulation) fluorometer. Most photophysiological parameters correlated with changes in environmental conditions quantified by differences in water quality along the gradient. For example, maximum quantum yield ( Fv/ Fm) increased and PAR-absorptivity decreased as water quality improved along the gradient from nearshore reefs (low irradiance, elevated nutrients and sediments) to outer islands (high irradiance, low nutrients and sediments). For apparent photosynthetic rate (PS max) and minimum saturating irradiance ( Ek), the direction of change differed depending on sampling depth, suggesting that different mechanisms of photo-acclimatisation operated between shallow and deep corals. Deep corals conformed to typical patterns of light/shade acclimatisation whereas shallow corals exhibited reduced PS max and Ek with improving water quality coinciding with greater heat dissipation (NPQ 241). Furthermore, deep corals on nearshore reefs exhibited elevated Q241 in comparison to outer islands possibly due to effects of sedimentation and/or pollutants rather than irradiance. These results highlight the importance of mesoscale sampling to obtain useful estimates of the variability of photophysiological parameters, particularly if such measures are to be used as bioindicators of the condition of coral reefs.

  19. Investigations on gamma ray induced chlorophyll variegated mutants

    International Nuclear Information System (INIS)

    Datta, S.K.; Dwivedi, A.K.; Banerji, B.K.

    1995-01-01

    Considering economic importance of chlorophyll variegation in floriculture trade an attempt was made for cytological, anatomical and biochemical analysis of four Bougainvillea and Lantana depressa chlorophyll variegated mutants for better and clear understanding of origin of chlorophyll variegation. No cytological evidence could be detected for their origin. Anatomical and biochemical examinations revealed that chlorophyll variegation in these mutants were due to changes in biosynthesis pathways and time of chlorophyll synthesis in palisade and spongy mesophyll cells. (author). 7 refs., 3 figs., 3 tabs

  20. Photosynthesis and chlorophyll fluorescence reaction to different shade stresses of weak light sensitive maize

    International Nuclear Information System (INIS)

    Wang, J.; Li, F.; Shi, Z.; Huang, H.; Jia, S.

    2017-01-01

    A split-plot experimental study was conducted to evaluate the effect of different shade stresses on photosynthesis and chlorophyll fluorescence of maize leaves.The experiment was designed on the south farm of Special Corn Institute, Shenyang Agricultural University, China.Data was collected from the day maize tasseled (Jul. 21) to the beginning of grouting (Aug.12 ) under 18%, 28%, 38%, 60%, and 75% shade stress to determine indexes such as photosynthesis and chlorophyll fluorescence after 15 days of shade treatment. Pairs of near-isogenic lines (NILs) of Shennong 98A (a barren stalk inbred line) and Shennong 98B (an un-barren stalk inbred line) were used as experimental materials to further reveal photosynthetic mechanisms of weak light sensitive maize when exposed to weak light conditions. Thus, a foundation was established for high density-resistant (shade resistant) corn breeding,while identifying weak light sensitive varieties. After shading treatment, chlorophyll a and total chlorophyll content of both varieties increased, chlorophyll b content first increased, followed by a decrease, while the net photosynthetic rate and stomatal conductance showed a gradually decreasing trend. The changing trends of photochemical quenching coefficient(qp) and effective quantum yield of PSII photochemistry (FPSII)were similar, FPSII and qP increased significantly as shading stress increased from 18% to 38%;however, FPSII and qP declined significantly under 60% and 75% shading stresses. The changing trend of NPQ was opposite to FPSII and qP. A comparison of both inbred lines showed that photosynthesis and chlorophyll fluorescence characteristics of Shennong 98B were superior to Shennong 98A. This study revealed the relationships between weak light sensitive lines and shade intensities by comparing differences in photosynthesis and chlorophyll fluorescence parameters. (author)

  1. Bacterial communities of two ubiquitous Great Barrier Reef corals reveals both site- and species-specificity of common bacterial associates.

    Directory of Open Access Journals (Sweden)

    E Charlotte E Kvennefors

    Full Text Available BACKGROUND: Coral-associated bacteria are increasingly considered to be important in coral health, and altered bacterial community structures have been linked to both coral disease and bleaching. Despite this, assessments of bacterial communities on corals rarely apply sufficient replication to adequately describe the natural variability. Replicated data such as these are crucial in determining potential roles of bacteria on coral. METHODOLOGY/PRINCIPAL FINDINGS: Denaturing Gradient Gel Electrophoresis (DGGE of the V3 region of the 16S ribosomal DNA was used in a highly replicated approach to analyse bacterial communities on both healthy and diseased corals. Although site-specific variations in the bacterial communities of healthy corals were present, host species-specific bacterial associates within a distinct cluster of gamma-proteobacteria could be identified, which are potentially linked to coral health. Corals affected by "White Syndrome" (WS underwent pronounced changes in their bacterial communities in comparison to healthy colonies. However, the community structure and bacterial ribotypes identified in diseased corals did not support the previously suggested theory of a bacterial pathogen as the causative agent of the syndrome. CONCLUSIONS/SIGNIFICANCE: This is the first study to employ large numbers of replicated samples to assess the bacterial communities of healthy and diseased corals, and the first culture-independent assessment of bacterial communities on WS affected Acroporid corals on the GBR. Results indicate that a minimum of 6 replicate samples are required in order to draw inferences on species, spatial or health-related changes in community composition, as a set of clearly distinct bacterial community profiles exist in healthy corals. Coral bacterial communities may be both site and species specific. Furthermore, a cluster of gamma-proteobacterial ribotypes may represent a group of specific common coral and marine

  2. Massive bleaching of coral reefs induced by the 2010 ENSO, Puerto Cabello, Venezuela.

    Science.gov (United States)

    del Mónaco, Carlos; Haiek, Gerard; Narciso, Samuel; Galindo, Miguel

    2012-06-01

    El Niño Southern Oscillation (ENSO) has generated global coral massive bleaching. The aim of this work was to evaluate the massive bleaching of coral reefs in Puerto Cabello, Venezuela derived from ENSO 2010. We evaluated the bleaching of reefs at five localities both at three and five meter depth. The coral cover and densities of colonies were estimated. We recorded living coral cover, number and diameter of bleached and non-bleached colonies of each coral species. The colonies were classified according to the proportion of bleached area. Satellite images (Modis Scar) were analyzed for chlorophyll-a concentration and temperature in August, September, October and November from 2008-2010. Precipitation, wind speed and air temperature information was evaluated in meteorological data for 2009 and 2010. A total of 58.3% of colonies, belonging to 11 hexacoral species, were affected and the greatest responses were observed in Colpophyllia natans, Montastraea annularis and Montastraeafaveolata. The most affected localities were closer to the mainland and had a bleached proportion up to 62.73+/-36.55%, with the highest proportion of affected colonies, whereas the farthest locality showed 20.25+/-14.00% bleached and the smallest proportion. The salinity in situ varied between 30 and 33ppm and high levels of turbidity were observed. According to the satellite images, in 2010 the surface water temperature reached 31 degree C in August, September and October, and resulted higher than those registered in 2008 and 2009. Regionally, chlorophyll values were higher in 2010 than in 2008 and 2009. The meteorological data indicated that precipitation in November 2010 was three times higher than in November 2009. Massive coral bleaching occurred due to a three month period of high temperatures followed by one month of intense ENSO-associated precipitation. However, this latter factor was likely the trigger because of the bleaching gradient observed.

  3. Effect of road side dust pollution on the growth and total chlorophyll ...

    African Journals Online (AJOL)

    The effect of dust in Vitis vinifera L. on its pigmentation and growth was studied in 2012. Measurements were taken for plants in the Campus University of Balochistan, Quetta. A significant reduction in plant length, cover, number of leaves and total chlorophyll contents for V. vinifera L. was observed. The maximum reduction ...

  4. BEL1-LIKE HOMEODOMAIN 11 regulated chloroplast development and chlorophyll synthesis in tomato fruit

    Science.gov (United States)

    Chloroplast development and chlorophyll content and metabolism in unripe tomato contribute to the growth and development of the fruit, and also the ripe fruit quality, but the mechanism is poorly understood. In this work, seven homeobox-containing transcription factors (TFs) with specific ripening-a...

  5. Coral Reef Biological Criteria

    Science.gov (United States)

    Coral reefs worldwide are experiencing decline from a variety of stressors. Some important stressors are land-based sources of pollution and human activities in the coastal zone. However, few tools are available to offset the impact of these stressors. The Clean Water Act (CWA...

  6. Raiding the Coral Nurseries?

    Directory of Open Access Journals (Sweden)

    Alison M. Jones

    2011-08-01

    Full Text Available A recent shift in the pattern of commercial harvest in the Keppel Island region of the southern inshore Great Barrier Reef raises concern about the depletion of a number of relatively rare restricted range taxa. The shift appears to be driven by demand from the United States (US for corals for domestic aquaria. Data from the annual status reports from the Queensland Coral Fishery were compared with export trade data to the US from the Convention on International Trade in Endangered Species (CITES. Evidence was found of recent increases in the harvest of species from the Mussidae family (Acanthastrea spp. which appears to be largely driven by demand from the US. On present trends, the industry runs the risk of localized depletion of Blastomussa and Scolymia; evidenced by an increase in the harvest of small specimens and the trend of decreasing harvest despite a concurrent increase in demand. Considering their relatively high sediment tolerance compared to other reef-building species, and the current lack of information about their functional role in reef stability, the trend raises concerns about the impact of the harvest on local coral communities. The recent shift in harvest patterns could have impacts on slow-growing species by allowing harvest beyond the rate of population regeneration. In light of these factors, combined with the value of such species to local tourism, a commercial coral fishery based on uncommon but highly sought-after species may not be ecologically sustainable or economically viable in the Keppels.

  7. Recent Trends in Global Ocean Chlorophyll

    Science.gov (United States)

    Gregg, Watson; Casey, Nancy

    2004-01-01

    Recent analyses of SeaWiFS data have shown that global ocean chlorophyll has increased more than 5% since 1998. The North Pacific ocean basin has increased nearly 19%. To understand the causes of these trends we have applied the newly developed NASA Ocean Biogeochemical Assimilation Model (OBAM), which is driven in mechanistic fashion by surface winds, sea surface temperature, atmospheric iron deposition, sea ice, and surface irradiance. The mode1 utilizes chlorophyll from SeaWiFS in a daily assimilation. The model has in place many of the climatic variables that can be expected to produce the changes observed in SeaWiFS data. Ths enables us to diagnose the model performance, the assimilation performance, and possible causes for the increase in chlorophyll.

  8. The spontaneous chlorophyll mutation frequency in barley

    DEFF Research Database (Denmark)

    Jørgensen, Jørgen Helms; Jensen, Hans Peter

    1986-01-01

    A total of 1866 barley plants were progeny tested in the greenhouse. Twenty-five plants segregated for newly arisen, spontaneous chlorophyll mutant genes. Among the total of 470,129 seedlings screened there were 79 mutants (1.7 .+-. 0.6 .times. 10-4). The data are added to data from three similar...... materials and the resulting estimate of the chlorophyll mutant frequency is 1.6 .times. 10-4 in about 1.43 million seedlings. The estimate of the chlorophyll mutation rate per generation is close to 67.3 .times. 10-4 per diploid genome or in the order of 6 .times. 10-7 per locus and haploid genome....

  9. Temperature Regimes Impact Coral Assemblages along Environmental Gradients on Lagoonal Reefs in Belize.

    Directory of Open Access Journals (Sweden)

    Justin H Baumann

    Full Text Available Coral reefs are increasingly threatened by global and local anthropogenic stressors such as rising seawater temperature, nutrient enrichment, sedimentation, and overfishing. Although many studies have investigated the impacts of local and global stressors on coral reefs, we still do not fully understand how these stressors influence coral community structure, particularly across environmental gradients on a reef system. Here, we investigate coral community composition across three different temperature and productivity regimes along a nearshore-offshore gradient on lagoonal reefs of the Belize Mesoamerican Barrier Reef System (MBRS. A novel metric was developed using ultra-high-resolution satellite-derived estimates of sea surface temperatures (SST to classify reefs as exposed to low (lowTP, moderate (modTP, or high (highTP temperature parameters over 10 years (2003 to 2012. Coral species richness, abundance, diversity, density, and percent cover were lower at highTP sites relative to lowTP and modTP sites, but these coral community traits did not differ significantly between lowTP and modTP sites. Analysis of coral life history strategies revealed that highTP sites were dominated by hardy stress-tolerant and fast-growing weedy coral species, while lowTP and modTP sites consisted of competitive, generalist, weedy, and stress-tolerant coral species. Satellite-derived estimates of Chlorophyll-a (chl-a were obtained for 13-years (2003-2015 as a proxy for primary production. Chl-a concentrations were highest at highTP sites, medial at modTP sites, and lowest at lowTP sites. Notably, thermal parameters correlated better with coral community traits between site types than productivity, suggesting that temperature (specifically number of days above the thermal bleaching threshold played a greater role in defining coral community structure than productivity on the MBRS. Dominance of weedy and stress-tolerant genera at highTP sites suggests that corals

  10. Seasonal mesophotic coral bleaching of Stylophora pistillata in the Northern Red Sea.

    Science.gov (United States)

    Nir, Orit; Gruber, David F; Shemesh, Eli; Glasser, Eliezra; Tchernov, Dan

    2014-01-01

    Coral bleaching occurs when environmental stress induces breakdown of the coral-algae symbiosis and the host initiates algae expulsion. Two types of coral bleaching had been thoroughly discussed in the scientific literature; the first is primarily associated with mass coral bleaching events; the second is a seasonal loss of algae and/or pigments. Here, we describe a phenomenon that has been witnessed for repeated summers in the mesophotic zone (40-63 m) in the northern Red Sea: seasonal bleaching and recovery of several hermatypic coral species. In this study, we followed the recurring bleaching process of the common coral Stylophora pistillata. Bleaching occurred from April to September with a 66% decline in chlorophyll a concentration, while recovery began in October. Using aquarium and transplantation experiments, we explored environmental factors such as temperature, photon flux density and heterotrophic food availability. Our experiments and observations did not yield one single factor, alone, responsible for the seasonal bleaching. The dinoflagellate symbionts (of the genus Symbiodinium) in shallow (5 m) Stylophora pistillata were found to have a net photosynthetic rate of 56.98-92.19 µmol O2 cm(-2) day(-1). However, those from mesophotic depth (60 m) during months when they are not bleached are net consumers of oxygen having a net photosynthetic rate between -12.86 - (-10.24) µmol O2 cm(-2) day(-1). But during months when these mesophotic corals are partially-bleached, they yielded higher net production, between -2.83-0.76 µmol O2 cm(-2) day(-1). This study opens research questions as to why mesophotic zooxanthellae are more successfully meeting the corals metabolic requirements when Chl a concentration decreases by over 60% during summer and early fall.

  11. Seasonal mesophotic coral bleaching of Stylophora pistillata in the Northern Red Sea.

    Directory of Open Access Journals (Sweden)

    Orit Nir

    Full Text Available Coral bleaching occurs when environmental stress induces breakdown of the coral-algae symbiosis and the host initiates algae expulsion. Two types of coral bleaching had been thoroughly discussed in the scientific literature; the first is primarily associated with mass coral bleaching events; the second is a seasonal loss of algae and/or pigments. Here, we describe a phenomenon that has been witnessed for repeated summers in the mesophotic zone (40-63 m in the northern Red Sea: seasonal bleaching and recovery of several hermatypic coral species. In this study, we followed the recurring bleaching process of the common coral Stylophora pistillata. Bleaching occurred from April to September with a 66% decline in chlorophyll a concentration, while recovery began in October. Using aquarium and transplantation experiments, we explored environmental factors such as temperature, photon flux density and heterotrophic food availability. Our experiments and observations did not yield one single factor, alone, responsible for the seasonal bleaching. The dinoflagellate symbionts (of the genus Symbiodinium in shallow (5 m Stylophora pistillata were found to have a net photosynthetic rate of 56.98-92.19 µmol O2 cm(-2 day(-1. However, those from mesophotic depth (60 m during months when they are not bleached are net consumers of oxygen having a net photosynthetic rate between -12.86 - (-10.24 µmol O2 cm(-2 day(-1. But during months when these mesophotic corals are partially-bleached, they yielded higher net production, between -2.83-0.76 µmol O2 cm(-2 day(-1. This study opens research questions as to why mesophotic zooxanthellae are more successfully meeting the corals metabolic requirements when Chl a concentration decreases by over 60% during summer and early fall.

  12. Chlorophyll mutants in Phaseolus vulgaris (L.) Savi

    International Nuclear Information System (INIS)

    Svetleva, D.; Petkova, S.

    1991-01-01

    Three-year investigations were conducted on chlorophyll mutants of three type: viridissima, claroviridis, flavoviridis, viridocostata and xanthomarginata produced post gamma irradiation ( 60 Co, 8 krad, 280 rad/min). Cell division rate in spectrum and in quantity of induced aberrations was found to have no significant differences with the control. Chlorophyll mutations compared to the control are less developed and their productive characters are less manifested. Cell division rate and the quantity of induced aberrations have no relation to the elements of productivity in the mutants investigated. 3 tabs., 12 refs

  13. Epithermal neutron activation analysis of major and trace elements in Red Sea scleractinian corals

    International Nuclear Information System (INIS)

    Abdo, S.Y.; Sherif, M.M.; Frontasyeva, M.V.

    2017-01-01

    Five corals belonging to common scleractinian reef-building species, and collected from Gulf of Suez, Egypt were subjected to neutron activation analysis. The content of 26 elements: Na, Mg, Cl, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, As, Br, Rb, Sr, Sb, I, Cs, Ba, La, Ce, Gd, Hf, Th, and U was experimentally determined. Ca and Sr have the highest content i.e. 38.4-39.5% and 0.73-0.78% respectively while, the content of all other elements was within the ranges reported for the worldwide corals. For a better understanding of the coral exoskeleton elemental content, the partition coefficient calculated for all determined elements showed a wide range of values varying from 2 × 10 -4 in the case of Cl to 2 × 10 3 for Ce and other insoluble elements. Although all corals were collected in the vicinity of the Port Suez no traces of anthropogenic contamination were evidenced. (author)

  14. Identification of a Chlorophyll Dephytylase Involved in Chlorophyll Turnover in Arabidopsis[OPEN

    Science.gov (United States)

    2016-01-01

    Chlorophyll turns over in green organs during photosystem repair and is salvaged via de- and rephytylation, but the enzyme involved in dephytylation is unknown. We have identified an Arabidopsis thaliana thylakoid protein with a putative hydrolase domain that can dephytylate chlorophyll in vitro and in vivo. The corresponding locus, CHLOROPHYLL DEPHYTYLASE1 (CLD1), was identified by mapping a semidominant, heat-sensitive, missense allele (cld1-1). CLD1 is conserved in oxygenic photosynthetic organisms, sharing structural similarity with pheophytinase, which functions in chlorophyll breakdown during leaf senescence. Unlike pheophytinase, CLD1 is predominantly expressed in green organs and can dephytylate chlorophyll in vitro. The specific activity is significantly higher for the mutant protein encoded by cld1-1 than the wild-type enzyme, consistent with the semidominant nature of the cld1-1 mutation. Supraoptimal CLD1 activities in cld1-1 mutants and transgenic seedlings led to the proportional accumulation of chlorophyllides derived from chlorophyll dephytylation after heat shock, which resulted in light-dependent cotyledon bleaching. Reducing CLD1 expression diminished thermotolerance and the photochemical efficiency of photosystem II under prolonged moderate heat stress. Taken together, our results suggest that CLD1 is the long-sought enzyme for removing the phytol chain from chlorophyll during its turnover at steady state within the chloroplast. PMID:27920339

  15. Identification of a Chlorophyll Dephytylase Involved in Chlorophyll Turnover in Arabidopsis.

    Science.gov (United States)

    Lin, Yao-Pin; Wu, Meng-Chen; Charng, Yee-Yung

    2016-12-01

    Chlorophyll turns over in green organs during photosystem repair and is salvaged via de- and rephytylation, but the enzyme involved in dephytylation is unknown. We have identified an Arabidopsis thaliana thylakoid protein with a putative hydrolase domain that can dephytylate chlorophyll in vitro and in vivo. The corresponding locus, CHLOROPHYLL DEPHYTYLASE1 (CLD1), was identified by mapping a semidominant, heat-sensitive, missense allele (cld1-1). CLD1 is conserved in oxygenic photosynthetic organisms, sharing structural similarity with pheophytinase, which functions in chlorophyll breakdown during leaf senescence. Unlike pheophytinase, CLD1 is predominantly expressed in green organs and can dephytylate chlorophyll in vitro. The specific activity is significantly higher for the mutant protein encoded by cld1-1 than the wild-type enzyme, consistent with the semidominant nature of the cld1-1 mutation. Supraoptimal CLD1 activities in cld1-1 mutants and transgenic seedlings led to the proportional accumulation of chlorophyllides derived from chlorophyll dephytylation after heat shock, which resulted in light-dependent cotyledon bleaching. Reducing CLD1 expression diminished thermotolerance and the photochemical efficiency of photosystem II under prolonged moderate heat stress. Taken together, our results suggest that CLD1 is the long-sought enzyme for removing the phytol chain from chlorophyll during its turnover at steady state within the chloroplast. © 2016 American Society of Plant Biologists. All rights reserved.

  16. Seaweed-coral interactions: variance in seaweed allelopathy, coral susceptibility, and potential effects on coral resilience.

    Directory of Open Access Journals (Sweden)

    Roberta M Bonaldo

    Full Text Available Tropical reefs are in global decline with seaweeds commonly replacing corals. Negative associations between macroalgae and corals are well documented, but the mechanisms involved, the dynamics of the interactions, and variance in effects of different macroalgal-coral pairings are poorly investigated. We assessed the frequency, magnitude, and dynamics of macroalgal-coral competition involving allelopathic and non-allelopathic macroalgae on three, spatially grouped pairs of no-take Marine Protected Areas (MPAs and non-MPAs in Fiji. In non-MPAs, biomass of herbivorous fishes was 70-80% lower, macroalgal cover 4-9 fold higher, macroalgal-coral contacts 5-15 fold more frequent and 23-67 fold more extensive (measured as % of colony margin contacted by macroalgae, and coral cover 51-68% lower than in MPAs. Coral contacts with allelopathic macroalgae occurred less frequently than expected by chance across all sites, while contact with non-allelopathic macroalgae tended to occur more frequently than expected. Transplants of allelopathic macroalgae (Chlorodesmis fastigiata and Galaxaura filamentosa against coral edges inflicted damage to Acropora aspera and Pocillopora damicornis more rapidly and extensively than to Porites cylindrica and Porites lobata, which appeared more resistant to these macroalgae. Montipora digitata experienced intermediate damage. Extent of damage from macroalgal contact was independent of coral colony size for each of the 10 macroalgal-coral pairings we established. When natural contacts with Galaxaura filamentosa were removed in the field, recovery was rapid for Porites lobata, but Pocillopora damicornis did not recover and damage continued to expand. As macroalgae increase on overfished tropical reefs, allelopathy could produce feedbacks that suppress coral resilience, prevent coral recovery, and promote the stability of algal beds in habitats previously available to corals.

  17. How is the chlorophyll count affected by burned and unburned marsh areas?

    Science.gov (United States)

    Kendrick, C.

    2017-12-01

    Does marsh burnings, either man made or natural, hinder or help Louisiana's vitally important coastal plant life? Does the carbon produced from the fires have a negative effect on the chlorophyll count of these precious living protective barriers? Or does it help contribute to raising the plants chlorophyll count? Along Louisiana's Gulf Coast, marsh burnings are conducted every 2-4 years to destroy some of the Spartina patens. Fires and smoke may have an effect on the chlorophyll count of the plants found in Louisiana's marshes. Peat burns, root burns, and cover burns are the three types of marsh fires. These burns can be either man made or started by natural causes. Peat burns occur when the soil is dry due to a drained marsh. Root burns occur when plant roots are burned without the soil being consumed. Cover burns occur when several centimeters of water covers the soil. Cover burns are often used by Wildlife and Fisheries personnel to promote preferred plant food growth like Scirpus olneyi rather than the dominant Spartina patens. Our project was conducted by testing marsh plants and obtaining chlorophyll count of both a burned (cover burn) and an unburned area. Approximately one year after the burn, in August 2015, we tested the burned area's site. We retested the same site in December 2016. The results from our testing showed that there was a slightly higher chlorophyll count in the burned area. The chlorophyll count average from the two testing days was 33.5 in the burned area and 30.15 in the unburned area. Our hypothesis was that the chlorophyll content of "controlled" burned wetland areas will have a higher amount than the "no" burn area. The experiment results supported this hypothesis by showing an increase of 3.35 average in the burned area.

  18. Spectral response of the coral rubble, living corals, and dead corals: study case on the Spermonde Archipelago, Indonesia

    Science.gov (United States)

    Nurdin, Nurjannah; Komatsu, Teruhisa; Yamano, Hiroya; Arafat, Gulam; Rani, Chair; Akbar AS, M.

    2012-10-01

    Coral reefs play important ecological services such as providing foods, biodiversity, nutrient recycling etc. for human society. On the other hand, they are threatened by human impacts such as illegal fishing and environmental changes such as rises of sea water temperature and sea level due to global warming. Thus, it is very important to monitor dynamic spatial distributions of coral reefs and related habitats such as coral rubble, dead coral, bleached corals, seagrass, etc. Hyperspectral data, in particular, offer high potential for characterizing and mapping coral reefs because of their capability to identify individual reef components based on their detailed spectral response. We studied the optical properties by measuring in situ spectra of living corals, dead coral and coral rubble covered with algae. Study site was selected in Spermonde archipelago, South Sulawesi, Indonesia because this area is included in the highest diversity of corals in the world named as Coral Triangle, which is recognized as the global centre of marine biodiversity and a global priority for conservation. Correlation analysis and cluster analysis support that there are distinct differences in reflectance spectra among categories. Common spectral characteristic of living corals, dead corals and coral rubble covered with algae was a reflectance minimum at 674 nm. Healthy corals, dead coral covered with algae and coral rubble covered with algae showed high similarity of spectral reflectance. It is estimated that this is due to photsynthetic pigments.

  19. Threatened Caribbean coral is able to mitigate the adverse effects of ocean acidification on calcification by increasing feeding rate.

    Directory of Open Access Journals (Sweden)

    Erica K Towle

    Full Text Available Global climate change threatens coral growth and reef ecosystem health via ocean warming and ocean acidification (OA. Whereas the negative impacts of these stressors are increasingly well-documented, studies identifying pathways to resilience are still poorly understood. Heterotrophy has been shown to help corals experiencing decreases in growth due to either thermal or OA stress; however, the mechanism by which it mitigates these decreases remains unclear. This study tested the ability of coral heterotrophy to mitigate reductions in growth due to climate change stress in the critically endangered Caribbean coral Acropora cervicornis via changes in feeding rate and lipid content. Corals were either fed or unfed and exposed to elevated temperature (30°C, enriched pCO2 (800 ppm, or both (30°C/800 ppm as compared to a control (26°C/390 ppm for 8 weeks. Feeding rate and lipid content both increased in corals experiencing OA vs. present-day conditions, and were significantly correlated. Fed corals were able to maintain ambient growth rates at both elevated temperature and elevated CO2, while unfed corals experienced significant decreases in growth with respect to fed conspecifics. Our results show for the first time that a threatened coral species can buffer OA-reduced calcification by increasing feeding rates and lipid content.

  20. Afterglow of chlorophyll in vivo and photosynthesis

    NARCIS (Netherlands)

    Goedheer, J.C.

    1962-01-01

    Two pigment systems are involved in the afterglow of chlorophyll a-containing cells. Absorption in only one of these systems (promoting or “p” system) is effective in producing luminescence. If light is absorbed simultaneously by the other (quenching or “q” system), a decrease in luminescence

  1. SHORT COMMUNICATION ISOLATION OF CHLOROPHYLL A ...

    African Journals Online (AJOL)

    a

    chromatography (CCC) technique has been applied to the separation of chlorophyll a from ... auxiliary gas flow rate, 0.06 L min-1; ion spray voltage, 3.5 kV; capillary .... This work presents a successful application of column chromatography ...

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

    Science.gov (United States)

    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. Overview of remote sensing of chlorophyll flourescene in ocean waters

    African Journals Online (AJOL)

    Overview of remote sensing of chlorophyll flourescene in ocean waters. ... Besides empirical algorithms with the blue-green ratio, the algorithms based on ... between fluorescence and chlorophyll concentration and the red shift phenomena.

  4. Joint Leaf chlorophyll and leaf area index retrieval from Landsat data using a regularized model inversion system

    Science.gov (United States)

    Leaf area index (LAI) and leaf chlorophyll (Chl) content represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination, LAI and leaf Chl content provide critical information on vegetation density, vitality and photosynt...

  5. Nitrification in reef corals

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Wafar, S.; David, J.J.

    . An estimate of the density of nitrifying bacteria on living corals can be made by comparing the nitrifying rates of bacterial cells and the rate of production of NO,-. Kaplan (1983) summarized the growth con- stants of marine nitrifying bacteria... Reef Con=. 3: 395-399. -, C. R. WILKINSON, V. p. VICENTE, J. M. MORELL, AND E. OTERO. 1988. Nitrate release by Carib- bean reef sponges. Limnol. Oceanogr. 33: 114- 120. CROSSLAND, C. J., AND D. J. BARNES. 1983. Dissolved nutrients and organic...

  6. Physiological and isotopic responses of scleractinian corals to ocean acidification

    Science.gov (United States)

    Krief, Shani; Hendy, Erica J.; Fine, Maoz; Yam, Ruth; Meibom, Anders; Foster, Gavin L.; Shemesh, Aldo

    2010-09-01

    Uptake of anthropogenic CO 2 by the oceans is altering seawater chemistry with potentially serious consequences for coral reef ecosystems due to the reduction of seawater pH and aragonite saturation state ( Ωarag). The objectives of this long-term study were to investigate the viability of two ecologically important reef-building coral species, massive Porites sp. and Stylophora pistillata, exposed to high pCO 2 (or low pH) conditions and to observe possible changes in physiologically related parameters as well as skeletal isotopic composition. Fragments of Porites sp. and S. pistillata were kept for 6-14 months under controlled aquarium conditions characterized by normal and elevated pCO 2 conditions, corresponding to pH T values of 8.09, 7.49, and 7.19, respectively. In contrast with shorter, and therefore more transient experiments, the long experimental timescale achieved in this study ensures complete equilibration and steady state with the experimental environment and guarantees that the data provide insights into viable and stably growing corals. During the experiments, all coral fragments survived and added new skeleton, even at seawater Ωarag zooxanthellae, along with physiological data (such as skeletal growth, tissue biomass, zooxanthellae cell density, and chlorophyll concentration) allow for a direct comparison with corals living under normal conditions and sampled simultaneously. Skeletal growth and zooxanthellae density were found to decrease, whereas coral tissue biomass (measured as protein concentration) and zooxanthellae chlorophyll concentrations increased under high pCO 2 (low pH) conditions. Both species showed similar trends of δ 11B depletion and δ 18O enrichment under reduced pH, whereas the δ 13C results imply species-specific metabolic response to high pCO 2 conditions. The skeletal δ 11B values plot above seawater δ 11B vs. pH borate fractionation curves calculated using either the theoretically derived α B value of 1

  7. Chlorophyll Synthase under Epigenetic Surveillance Is Critical for Vitamin E Synthesis, and Altered Expression Affects Tocopherol Levels in Arabidopsis1[OPEN

    Science.gov (United States)

    Zhang, Chunyu; Zhang, Wei; Ren, Guodong; Li, Delin; Cahoon, Rebecca E.; Chen, Ming; Zhou, Yongming; Yu, Bin

    2015-01-01

    Chlorophyll synthase catalyzes the final step in chlorophyll biosynthesis: the esterification of chlorophyllide with either geranylgeranyl diphosphate or phytyl diphosphate (PDP). Recent studies have pointed to the involvement of chlorophyll-linked reduction of geranylgeranyl by geranylgeranyl reductase as a major pathway for the synthesis of the PDP precursor of tocopherols. This indirect pathway of PDP synthesis suggests a key role of chlorophyll synthase in tocopherol production to generate the geranylgeranyl-chlorophyll substrate for geranylgeranyl reductase. In this study, contributions of chlorophyll synthase to tocopherol formation in Arabidopsis (Arabidopsis thaliana) were explored by disrupting and altering expression of the corresponding gene CHLOROPHYLL SYNTHASE (CHLSYN; At3g51820). Leaves from the homozygous chlysyn1-1 null mutant were nearly devoid of tocopherols, whereas seeds contained only approximately 25% of wild-type tocopherol levels. Leaves of RNA interference lines with partial suppression of CHLSYN displayed marked reductions in chlorophyll but up to a 2-fold increase in tocopherol concentrations. Cauliflower mosaic virus35S-mediated overexpression of CHLSYN unexpectedly caused a cosuppression phenotype at high frequencies accompanied by strongly reduced chlorophyll content and increased tocopherol levels. This phenotype and the associated detection of CHLSYN-derived small interfering RNAs were reversed with CHLSYN overexpression in rna-directed rna polymerase6 (rdr6), which is defective in RNA-dependent RNA polymerase6, a key enzyme in sense transgene-induced small interfering RNA production. CHLSYN overexpression in rdr6 had little effect on chlorophyll content but resulted in up to a 30% reduction in tocopherol levels in leaves. These findings show that altered CHLSYN expression impacts tocopherol levels and also, show a strong epigenetic surveillance of CHLSYN to control chlorophyll and tocopherol synthesis. PMID:26048882

  8. Melatonin Improves the Photosynthetic Apparatus in Pea Leaves Stressed by Paraquat via Chlorophyll Breakdown Regulation and Its Accelerated de novo Synthesis

    Directory of Open Access Journals (Sweden)

    Katarzyna Szafrańska

    2017-05-01

    Full Text Available The positive effect of melatonin on the function of the photosynthetic apparatus is known, but little is known about the specific mechanisms of melatonin's action in plants. The influence of melatonin on chlorophyll metabolism of 24-day-old Pisum sativum L. seedlings during paraquat (PQ-induced oxidative stress was investigated in this study. Seeds were hydro-primed with water (H, 50 and 200 μM melatonin/water solutions (H-MEL50, H-MEL200, while non-primed seeds were used as controls (C. Increases in chlorophyllase activity (key enzyme in chlorophyll degradation and 5-aminolevulinic acid contents (the first compound in the porphyrin synthesis pathway were observed in H-MEL50 and H-MEL200 leaf disks. This suggests that melatonin may accelerate damaged chlorophyll breakdown and its de novo synthesis during the first hours of PQ treatment. Elevated level of pheophytin in control leaf disks following 24 h of PQ incubation probably was associated with an enhanced rate of chlorophyll degradation through formation of pheophytin as a chlorophyll derivative. This validates the hypothesis that chlorophyllide, considered for many years, as a first intermediate of chlorophyll breakdown is not. This is indicated by the almost unchanged chlorophyll to chlorophyllide ratio after 24 h of PQ treatment. However, prolonged effects of PQ-induced stress (48 h revealed extensive discolouration of control and water-treated leaf disks, while melatonin treatment alleviated PQ-induced photobleaching. Also the ratio of chlorophyll to chlorophyllide and porphyrin contents were significantly higher in plants treated with melatonin, which may indicate that this indoleamine both retards chlorophyll breakdown and stimulates its de novo synthesis during extended stress. We concluded that melatonin added into the seeds enhances the ability of pea seedlings to accelerate chlorophyll breakdown and its de novo synthesis before stress appeared and for several hours after, while

  9. Environmental Variability in the Florida Keys: Impacts on Coral Reef Resilience and Health

    Science.gov (United States)

    Soto, I. M.; Muller-Karger, F. E.

    2005-12-01

    Environmental variability contributes to both mass mortality and resilience in tropical coral reef communities. We assess variations in sea surface temperature (SST) and ocean color in the Florida Keys using satellite imagery, and provide insight into how this variability is associated with locations of resilient coral communities (those unaffected by or able to recover from major events). The project tests the hypothesis that areas with historically low environmental variability promote lower levels of coral reef resilience. Time series of SST from the Advanced Very High Resolution Radiometer (AVHRR) sensors and ocean color derived quantities (e.g., turbidity and chlorophyll) from the Sea-viewing Wide Field of View Sensor (SeaWiFS) are being constructed over the entire Florida Keys region for a period of twelve and nine years, respectively. These data will be compared with historical coral cover data derived from Landsat imagery (1984-2002). Improved understanding of the causes of coral reef decline or resilience will help protect and manage these natural treasures.

  10. Evaluation of Stony Coral Indicators for Coral Reef Management.

    Science.gov (United States)

    Colonies of reef-building stony corals at 57 stations around St. Croix, U.S. Virgin Islands were characterized by species, size and percentage of living tissue. Taxonomic, biological and physical indicators of coral condition were derived from these measurements and assessed for ...

  11. Assessing Coral Community Recovery from Coral Bleaching by ...

    African Journals Online (AJOL)

    The densities of small colonies were lowest at the northern sites, and small colonies of genera of corals that suffered from high bleaching and mortality during the El Niño Southern Oscillation in 1998 were less abundant in the north. These northern reefs are relatively isolated from sources of coral larvae from reefs in the ...

  12. Active oxygen participation in chlorophyll destruction and lipid peroxidation in SO/sub 2/-fumigated leaves of spinach

    Energy Technology Data Exchange (ETDEWEB)

    Shimazaki, K; Sakaki, T; Sugahara, K

    1980-01-01

    Chlorophyll a and carotenoids of spinach plants began to be destroyed in 2 to 3 hr after the initiation of fumigation with 2.0 ppM sulfur dioxide (SO/sub 2/) in light, whereas chlorophyll b was apparently undamaged during 8 hr of exposure to SO/sub 2/. The content of pheophytin a, chromatographically determined, was not changed by SO/sub 2/ fumigation. When leaf disks (phi = 10 mm), excised from the leaves fumigated with SO/sub 2/ at 2.0 ppM for 2 hr, were illuminated, chlorophyll a and carotenoids were broken down, but they were not destroyed in darkness. The destruction of chlorophyll a and carotenoids was suppressed under a stream of nitrogen. Chlorophyll a destruction was inhibited by free radical scavengers, 1,2-dihydroxbenzene-3,5-disulfonate (tiron), hydroquinone and ascorbate. The singlet oxygen scavengers, 1,4-diazabicyclo-(2,2,2)-octane (DABCO), methionine and histidine, and hydroxyl radical scavengers, benzoate and formate were without effect on the destruction of chlorophyll a. Chlorophyll a destruction was inhibited by the addition of superoxide dismutase (SOD) to the homogenate of SO/sub 2/-fumigated leaves. SO/sub 2/ fumigation for 2 hr reduced the activity of superoxide dismutase to 40% without producing the significant loss of chlorophyll. From these results we concluded that chlorophyll a destruction by SO/sub 2/ was due to superoxide radicals. Moreover, malondialdehyde (MDA), an indicator of lipid peroxidation, was accumulated in SO/sub 2/-fumigated leaves in light. MDA formation was inhibited by tiron and hydroquinone, and by DABCO but was not inhibited by benzoate and formate. MDA formation was increased by D/sub 2/O. From these results it was concluded that /sup 1/O/sub 2/ was involved in lipid peroxidation in SO/sub 2/-fumigated leaves.

  13. Osmoadjustment in the Coral Holobiont

    KAUST Repository

    Röthig, Till

    2017-04-01

    Coral reefs are under considerable decline. The framework builders in coral reefs are scleractinian corals, which comprise so-called holobionts, consisting of cnidarian host, algal symbionts (genus Symbiodinium), and other associated microbes. Corals are commonly considered stenohaline osmoconformers, possessing limited capability to adjust to salinity changes. However, corals differ in their ability to cope with different salinities. The underlying mechanisms have not yet been addressed. To further understand putative mechanisms involved, I examined coral holobiont osmoregulation conducting a range of experiments on the coral Fungia granulosa. In my research F. granulosa from the Red Sea exhibited pronounced physiological reactions (decreased photosynthesis, cessation of calcification) upon short-term incubations (4 h) to high salinity (55). However, during a 29-day in situ salinity transect experiment, coral holobiont photosynthesis was unimpaired under high salinity (49) indicating acclimatization. F. granulosa microbiome changes after the 29-day high salinity exposure aligned with a bacterial community restructuring that putatively supports the coral salinity acclimatization (osmolyte synthesis, nutrient fixation/cycling). Long-term incubations (7 d) of cultured Symbiodinium exhibited cell growth even at ‘extreme’ salinity levels of 25 and 55. Metabolic profiles of four Symbiodinium strains exposed to increased (55) and decreased (25) salinities for 4 h indicated distinct carbohydrates and amino acids to be putatively involved in the osmoadjustment. Importantly, under high salinity the osmolyte floridoside was consistently increased. This could be corroborated in the coral model Aiptasia and in corals from the Persian/Arabian Gulf, where floridoside was also markedly increased upon short- (15 h) and long-term (>24 months) exposure to high salinity, confirming an important role of floridoside in the osmoadjustment of cnidarian holobionts. This thesis

  14. A review of ocean chlorophyll algorithms and primary production models

    Science.gov (United States)

    Li, Jingwen; Zhou, Song; Lv, Nan

    2015-12-01

    This paper mainly introduces the five ocean chlorophyll concentration inversion algorithm and 3 main models for computing ocean primary production based on ocean chlorophyll concentration. Through the comparison of five ocean chlorophyll inversion algorithm, sums up the advantages and disadvantages of these algorithm,and briefly analyzes the trend of ocean primary production model.

  15. Contribution of chlorophyll fluorescence to the apparent vegetation reflectance

    International Nuclear Information System (INIS)

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

    2008-01-01

    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

  16. Chlorophyll Degradation: The Tocopherol Biosynthesis-Related Phytol Hydrolase in Arabidopsis Seeds Is Still Missing1[C][W][OPEN

    Science.gov (United States)

    Zhang, Wei; Liu, Tianqi; Ren, Guodong; Hörtensteiner, Stefan; Zhou, Yongming; Cahoon, Edgar B.; Zhang, Chunyu

    2014-01-01

    Phytyl diphosphate (PDP) is the prenyl precursor for tocopherol biosynthesis. Based on recent genetic evidence, PDP is supplied to the tocopherol biosynthetic pathway primarily by chlorophyll degradation and sequential phytol phosphorylation. Three enzymes of Arabidopsis (Arabidopsis thaliana) are known to be capable of removing the phytol chain from chlorophyll in vitro: chlorophyllase1 (CLH1), CLH2, and pheophytin pheophorbide hydrolase (PPH), which specifically hydrolyzes pheophytin. While PPH, but not chlorophyllases, is required for in vivo chlorophyll breakdown during Arabidopsis leaf senescence, little is known about the involvement of these phytol-releasing enzymes in tocopherol biosynthesis. To explore the origin of PDP for tocopherol synthesis, seed tocopherol concentrations were determined in Arabidopsis lines engineered for seed-specific overexpression of PPH and in single and multiple mutants in the three genes encoding known dephytylating enzymes. Except for modestly increasing tocopherol content observed in the PPH overexpressor, none of the remaining lines exhibited significantly reduced tocopherol concentrations, suggesting that the known chlorophyll-derived phytol-releasing enzymes do not play major roles in tocopherol biosynthesis. Tocopherol content of seeds from double mutants in NONYELLOWING1 (NYE1) and NYE2, regulators of chlorophyll degradation, had modest reduction compared with wild-type seeds, although mature seeds of the double mutant retained significantly higher chlorophyll levels. These findings suggest that NYEs may play limited roles in regulating an unknown tocopherol biosynthesis-related phytol hydrolase. Meanwhile, seeds of wild-type over-expressing NYE1 had lower tocopherol levels, suggesting that phytol derived from NYE1-dependent chlorophyll degradation probably doesn’t enter tocopherol biosynthesis. Potential routes of chlorophyll degradation are discussed in relation to tocopherol biosynthesis. PMID:25059706

  17. Effect of Water Stress and Sulfur Fertilizer on Grain Yield, Chlorophyll and Nutrient Status of Black Cumin (Nigella Sativa L.

    Directory of Open Access Journals (Sweden)

    M. Heidari

    2011-04-01

    Full Text Available In order to study the effects of water stress and different amounts of sulfur fertilizer on grain yield, nutrient status and chlorophyll content in black cumin (Nigella sativa L. a field experiment as split plot design with three replications was conducted at Ghaen city in 2009. Treatments included three levels of irrigation after 50, 100 and 150 mm evaporation from Class A pan as main plot and four levels of sulfur fertilizer including 0, 75, 150 and 225 kg/ha from bentonite-sulfur source as sub-plot. Statistical analysis of the results showed that water stress has significant effect on grain yield and essential oil of black cumin. At the level of 150 mm evaporation from Class A pan, the grain yield decreased by 22.8% and essential oil by 27.6%. Application of 225 kg/ha sulfur fertilizer increased grain yield up to 7.2%. Water stress and sulfur fertilizer treatments had only significant effect on chlorophyll a content. However, water stress decreased chlorophyll a content, but sulfur fertilizer application up to 225 kg/ha increased the content of chlorophyll a. In this study, water stress decreased potassium content in black cumin leaves, but increased the sodium and calcium accumulation. Although application of sulfur fertilizer affected significantly the potassium and magnesium contents in shoots, but did not have significant effect on sodium and calcium contents.

  18. Fungal invasion of massive corals

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Raghukumar, S.

    Five species of corals from the Andaman Islands in the Bay of Bengal (Indian Ocean) have been regularly found to have single or multiple necrotic patches. The occurrence of such corals with necrotic patches varied from 10-50% in the field. Sections...

  19. The Biology and Economics of Coral Growth

    NARCIS (Netherlands)

    Osinga, R.; Schutter, M.; Griffioen, B.; Wijffels, R.H.; Verreth, J.A.J.; Shafit, S.; Henard, S.; Taruffi, M.; Gili, C.; Lavorano, S.

    2011-01-01

    To protect natural coral reefs, it is of utmost importance to understand how the growth of the main reef-building organisms-the zooxanthellate scleractinian corals-is controlled. Understanding coral growth is also relevant for coral aquaculture, which is a rapidly developing business. This review

  20. Coral assemblages are structured along a turbidity gradient on the Southwestern Gulf of Mexico, Veracruz

    Science.gov (United States)

    Jordán-Garza, A. G.; González-Gándara, C.; Salas-Pérez, J. J.; Morales-Barragan, A. M.

    2017-04-01

    Corals on the reef corridor of the southwestern Gulf of Mexico have evolved on a terrigenous shallow continental shelf under the influence of several natural river systems. As a result, water turbidity on these reefs can be high, with visibility as low as turbidity and chlorophyll-a, the coral species composition and environmental variables were analyzed for the three main reef systems of the reef corridor of the southwestern Gulf of Mexico. Completeness of the data set was assessed using species accumulation curves and non-parametric estimators of species richness. Differences in coral assemblages' composition between the reef systems were investigated using univariate (ANOVA) and multivariate (nMDS, ANOSIM, SIMPER) analyses and the relationship between the assemblages and environmental data was assessed using a forward selection process in canonical correspondence analysis (CCA) to eliminate non-significant environmental variables. The northern and central Veracruz reef systems share a similar number of coral species (p=0.78 mult. comp.) and both showed higher species richness than the southern system (pturbidity and productivity were significant on the final CCA configuration, which showed a gradient of increasing turbidity from north to south. Reef geomorphology and the effect of turbidity help explain differences in coral assemblages' composition. More studies are necessary to establish if turbidity could function as a refuge for future environmental stress. Each Veracruz reef system is at the same time unique and shares a pool of coral species. To protect these ecosystems it is necessary to effectively manage water quality and consider coral diversity on the reef corridor of the southwestern Gulf of Mexico.

  1. Hyperspectral Distinction of Two Caribbean Shallow-Water Corals Based on Their Pigments and Corresponding Reflectance

    Directory of Open Access Journals (Sweden)

    Juan L. Torres-Pérez

    2012-11-01

    Full Text Available The coloration of tropical reef corals is mainly due to their association with photosynthetic dinoflagellates commonly known as zooxanthellae. Combining High Performance Liquid Chromatography (HPLC, spectroscopy and derivative analysis we provide a novel approach to discriminate between the Caribbean shallow-water corals Acropora cervicornis and Porites porites based on their associated pigments. To the best of our knowledge, this is the first time that the total array of pigments found within the coral holobiont is reported. A total of 20 different pigments were identified including chlorophylls, carotenes and xanthophylls. Of these, eleven pigments were common to both species, eight were present only in A. cervicornis, and three were present only in P. porites. Given that these corals are living in similar physical conditions, we hypothesize that this pigment composition difference is likely a consequence of harboring different zooxanthellae clades with a possible influence of endolithic green or brown algae. We tested the effect of this difference in pigments on the reflectance spectra of both species. An important outcome was the correlation of total pigment concentration with coral reflectance spectra up to a 97% confidence level. Derivative analysis of the reflectance curves showed particular differences between species at wavelengths where several chlorophylls, carotenes and xanthophylls absorb. Within species variability of spectral features was not significant while interspecies variability was highly significant. We recognize that the detection of such differences with actual airborne or satellite remote sensors is extremely difficult. Nonetheless, based on our results, the combination of these techniques (HPLC, spectroscopy and derivative analysis can be used as a robust approach for the development of a site specific spectral library for the identification of shallow-water coral species. Studies (Torres-Pérez, NASA Postdoctoral

  2. Remobilization of Phytol from Chlorophyll Degradation Is Essential for Tocopherol Synthesis and Growth of Arabidopsis

    Science.gov (United States)

    vom Dorp, Katharina; Hölzl, Georg; Plohmann, Christian; Eisenhut, Marion; Abraham, Marion

    2015-01-01

    Phytol from chlorophyll degradation can be phosphorylated to phytyl-phosphate and phytyl-diphosphate, the substrate for tocopherol (vitamin E) synthesis. A candidate for the phytyl-phosphate kinase from Arabidopsis thaliana (At1g78620) was identified via a phylogeny-based approach. This gene was designated VITAMIN E DEFICIENT6 (VTE6) because the leaves of the Arabidopsis vte6 mutants are tocopherol deficient. The vte6 mutant plants are incapable of photoautotrophic growth. Phytol and phytyl-phosphate accumulate, and the phytyl-diphosphate content is strongly decreased in vte6 leaves. Phytol feeding and enzyme assays with Arabidopsis and recombinant Escherichia coli cells demonstrated that VTE6 has phytyl-P kinase activity. Overexpression of VTE6 resulted in increased phytyl-diphosphate and tocopherol contents in seeds, indicating that VTE6 encodes phytyl-phosphate kinase. The severe growth retardation of vte6 mutants was partially rescued by introducing the phytol kinase mutation vte5. Double mutant plants (vte5 vte6) are tocopherol deficient and contain more chlorophyll, but reduced amounts of phytol and phytyl-phosphate compared with vte6 mutants, suggesting that phytol or phytyl-phosphate are detrimental to plant growth. Therefore, VTE6 represents the missing phytyl-phosphate kinase, linking phytol release from chlorophyll with tocopherol synthesis. Moreover, tocopherol synthesis in leaves depends on phytol derived from chlorophyll, not on de novo synthesis of phytyl-diphosphate from geranylgeranyl-diphosphate. PMID:26452599

  3. SPECTROPHOTOMETRIC DETERMINATION OF CHLOROPHYLLS AND CAROTENOIDS. AN EFFECT OF SONICATION AND SAMPLE PROCESSING

    Directory of Open Access Journals (Sweden)

    Jana Braniša

    2014-02-01

    Full Text Available Chlorophylls and carotenoids are abundant pigments in plants, algae and cyanobacteria. In this study we verified the applicability of two previously developed UV-vis spectrophotometric methods for simultaneous quantitative determination of chlorophylls (a, b and carotenoids (lycopene, β-carotene or total carotenoids. The pigments were extracted from the strawberries, apricots and raspberries in both the acetone-water and acetone-hexane mixtures. Based on the statistical evaluation of the results the combination of mechanical disruption and sonication of fruit samples seems to be a suitable way to improve the pigment extraction efficiency from fruits in both types of solvents. In the case of apricot and raspberry fruit extracts the amount of chlorophylls and carotenoids calculated from the proposed equations was comparable to those published by other authors. However, the spectrophotometric determination of β-carotene content in strawberry acetone-hexane extract appeared to be problematic mainly due to the fact that carotenoids exhibited overlapping chlorophyll absorption bands. Overlap of bands leads to the negative values calculated from the proposed equation for the β-carotene content. The results indicate the limitations in use of the proposed set of equations for plant samples with comparable amounts of studied pigments.

  4. Microphytoplankton variations during coral spawning at Los Roques, Southern Caribbean

    Directory of Open Access Journals (Sweden)

    Francoise Cavada-Blanco

    2016-03-01

    Full Text Available Phytoplankton drives primary productivity in marine pelagic systems. This is also true for the oligotrophic waters in coral reefs, where natural and anthropogenic sources of nutrients can alter pelagic trophic webs. In this study, microphytoplankton assemblages were characterized for the first time in relation to expected coral spawning dates in the Caribbean. A hierarchical experimental design was used to examine these assemblages in Los Roques archipelago, Venezuela, at various temporal and spatial scales for spawning events in both 2007 and 2008. At four reefs, superficial water samples were taken daily for 9 days after the full moon of August, including days before, during and after the expected days of coral spawning. Microphytoplankton assemblages comprised 100 microalgae taxa at up to 50 cells per mL (mean ± 8 SD and showed temporal and spatial variations related to the coral spawning only in 2007. However, chlorophyll a concentrations increased during and after the spawning events in both years, and this was better matched with analyses of higher taxonomical groups (diatoms, cyanophytes and dinoflagellates, that also varied in relation to spawning times in 2007 and 2008, but asynchronously among reefs. Heterotrophic and mixotrophic dinoflagellates increased in abundance, correlating with a decrease of the diatom Cerataulina pelagica and an increase of the diatom Rhizosolenia imbricata. These variations occurred during and after the coral spawning event for some reefs in 2007. For the first time, a fresh-water cyanobacteria species of Anabaena was ephemerally found (only 3 days in the archipelago, at reefs closest to human settlements. Variability among reefs in relation to spawning times indicated that reef-specific processes such as water residence time, re-mineralization rates, and benthic-pelagic coupling can be relevant to the observed patterns. These results suggest an important role of microheterotrophic grazers in re

  5. Chronic exposure of corals to fine sediments: lethal and sub-lethal impacts.

    Directory of Open Access Journals (Sweden)

    Florita Flores

    Full Text Available Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata more than the upright branching species (Acropora millepora. The lowest sediment treatments that caused full colony mortality were 30 mg l(-1 TSS (25 mg cm(-2 day(-1 for M. aequituberculata and 100 mg l(-1 TSS (83 mg cm(-2 day(-1 for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue.

  6. Microbiome structure of the fungid coral Ctenactis echinata aligns with environmental differences

    KAUST Repository

    Roder, Cornelia

    2015-06-19

    The significance of bacteria for eukaryotic functioning is increasingly recognized. Coral reef ecosystems critically rely on the relationship between coral hosts and their intracellular photosynthetic dinoflagellates, but the role of the associated bacteria remains largely theoretical. Here, we set out to relate coral-associated bacterial communities of the fungid host species Ctenactis echinata to environmental settings (geographic location, substrate cover, summer/winter, nutrient and suspended matter concentrations) and coral host abundance. We show that bacterial diversity of C. echinata aligns with ecological differences between sites and that coral colonies sampled at the species’ preferred habitats are primarily structured by one bacterial taxon (genus Endozoicomonas) representing more than 60% of all bacteria. In contrast, host microbiomes from lower populated coral habitats are less structured and more diverse. Our study demonstrates that the content and structure of the coral microbiome aligns with environmental differences and denotes habitat adequacy. Availability of a range of coral host habitats might be important for the conservation of distinct microbiome structures and diversity.

  7. Chronic Exposure of Corals to Fine Sediments: Lethal and Sub-Lethal Impacts

    Science.gov (United States)

    Flores, Florita; Hoogenboom, Mia O.; Smith, Luke D.; Cooper, Timothy F.; Abrego, David; Negri, Andrew P.

    2012-01-01

    Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS) for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata) more than the upright branching species (Acropora millepora). The lowest sediment treatments that caused full colony mortality were 30 mg l−1 TSS (25 mg cm−2 day−1) for M. aequituberculata and 100 mg l−1 TSS (83 mg cm−2 day−1) for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue. PMID:22662225

  8. First record of multi-species synchronous coral spawning from Malaysia.

    Science.gov (United States)

    Chelliah, Alvin; Amar, Halimi Bin; Hyde, Julian; Yewdall, Katie; Steinberg, Peter D; Guest, James R

    2015-01-01

    Knowledge about the timing and synchrony of coral spawning has important implications for both the ecology and management of coral reef ecosystems. Data on the timing of spawning and extent of synchrony, however, are still lacking for many coral reefs, particularly from equatorial regions and from locations within the coral triangle. Here we present the first documentation of a multi-species coral spawning event from reefs around Pulau Tioman, Peninsular Malaysia, a popular diving and tourist destination located on the edge of the coral triangle. At least 8 coral species from 3 genera (Acropora, Montipora and Porites) participated in multi-species spawning over five nights in April 2014, between two nights before and two nights after the full moon. In addition, two Acropora species were witnessed spawning one night prior to the full moon in October 2014. While two of the Acropora species that reproduced in April (A. millepora and A. nasuta) exhibited highly synchronous spawning (100% of sampled colonies), two other common species (A. hyacinthus and A. digitifera) did not contain visible eggs in the majority of colonies sampled (i.e., Malaysia. These data provide further support for the contention that this phenomenon is a feature of all speciose coral assemblages, including equatorial reefs. More research is needed, however, to determine the seasonal cycles and extent of spawning synchrony on these reefs and elsewhere in Malaysia.

  9. Microbiome structure of the fungid coral Ctenactis echinata aligns with environmental differences

    KAUST Repository

    Roder, Cornelia; Bayer, Till; Aranda, Manuel; Kruse, Maren; Voolstra, Christian R.

    2015-01-01

    The significance of bacteria for eukaryotic functioning is increasingly recognized. Coral reef ecosystems critically rely on the relationship between coral hosts and their intracellular photosynthetic dinoflagellates, but the role of the associated bacteria remains largely theoretical. Here, we set out to relate coral-associated bacterial communities of the fungid host species Ctenactis echinata to environmental settings (geographic location, substrate cover, summer/winter, nutrient and suspended matter concentrations) and coral host abundance. We show that bacterial diversity of C. echinata aligns with ecological differences between sites and that coral colonies sampled at the species’ preferred habitats are primarily structured by one bacterial taxon (genus Endozoicomonas) representing more than 60% of all bacteria. In contrast, host microbiomes from lower populated coral habitats are less structured and more diverse. Our study demonstrates that the content and structure of the coral microbiome aligns with environmental differences and denotes habitat adequacy. Availability of a range of coral host habitats might be important for the conservation of distinct microbiome structures and diversity.

  10. [Progress of heterotrophic studies on symbiotic corals].

    Science.gov (United States)

    Yang, Yang-Chu-Qiao; Hong, Wen Ting; Wang, Shu Hong

    2017-12-01

    Heterotrophy of zooxanthellae symbiotic corals refers to the nutrition directly coming from food absorption, not the nutrition obtained from photosynthesis. Most ex situ propagation of symbiotic corals focused on the effects of irradiation, flow rate and water quality on corals, few of them involved in the demand and supply of coral heterotrophic nutrition. This paper reviewed the significance of heterotrophic nutrient supply to symbiotic corals from the sources of coral heterotrophic nutrition, the factors affecting the supply of coral heterotrophic nutrient, and the methods of how to study the coral heterotrophy. In general, the research of coral heterotrophy is just at the beginning stage, and future studies should focus on the inherent mechanism of coral feeding selection and developing more effective research methods.

  11. Uranium in coral skeletons determined by epithermal neutron activation analysis

    International Nuclear Information System (INIS)

    Ohde, S.; Hossain, M.M.M.; Ozaki, H.; Masuzawa, T.

    2003-01-01

    A simple and non-destructive method has been proposed for the routine determination of uranium by epithermal neutron activation analysis in coral skeletons. Using a cadmium capsule, about 0.1-0.2 g samples were irradiated for 6 hours in the Triga Mark II Reactor. Measurements of γ-ray ( 239 Np via 239 U) were performed with each sample and standard after cooling for about three days. Compared with a non-destructive thermal NAA, the present method was found to improve the sensitivity because it reduced the intense Compton background induced by 24 Na. Uranium in coral standards was determined within 2% of analytical precision. The data obtained for the carbonate standards are mostly consistent with reported values. The present method could be usefully applied to determine uranium contents in fossil corals from the Funafuti Atoll in the Pacific. The distribution of uranium between seawater and coral skeletons is also discussed in order to understand the environmental media in which the coral grew. (author)

  12. Physiological and Biogeochemical Responses of Super-Corals to Thermal Stress from the Northern Gulf of Aqaba, Red Sea

    Directory of Open Access Journals (Sweden)

    Andréa G. Grottoli

    2017-07-01

    Full Text Available Mass coral bleaching is increasing in frequency and severity, leading to the loss of coral abundance and diversity. However, some corals are less susceptible to bleaching than others and can provide a model for identifying the physiological and biogeochemical traits that underlie coral resilience to thermal stress. Corals from Eilat in the Gulf of Aqaba in the northern Red Sea do not bleach unless seawater temperatures are sustained at +6°C or higher above their average summer maximum. This extreme thermal tolerance qualifies these as super-corals, as most corals bleach when exposed to temperatures that are only +1–2°C above their thermal maximum. Here, we conducted a controlled bleaching experiment (+6°C for 37 days (equivalent to 32° heating weeks on three species of corals from Eilat: Stylophora pistillata, Pocillopora damicornis, and Favia favus. To assess the response of the holobiont to thermal stress, the following variables were measured on each coral: endosymbiotic algal cell density, Chlorophyll a, endosymbiotic mitotic cell division, total lipids, protein, carbohydrate, and the stable carbon (δ13C and oxygen (δ18O isotopic composition of the skeleton and the δ13C of the animal host tissue and endosymbiotic algae. While all three species appeared visibly bleached, their physiological and biogeochemical responses were species-specific. S. pistillata catabolized lipids but still maintained total energy reserves and biomass. Increases in both skeletal δ13C and δ18O indicates that calcification declined in this species. P. damicornis was the least affected by bleaching. It maintained its total energy reserves and biomass, and isotopic evidence suggests that it maintained calcification and was not dependent on heterotrophy for meeting metabolic demand when bleached. Finally, F. favus catabolized protein and carbohydrates, and suffered losses in total energy reserves and biomass. Nevertheless, isotopic evidence suggest that

  13. Coral reef bleaching: ecological perspectives

    Science.gov (United States)

    Glynn, P. W.

    1993-03-01

    Coral reef bleaching, the whitening of diverse invertebrate taxa, results from the loss of symbiotic zooxanthellae and/or a reduction in photosynthetic pigment concentrations in zooxanthellae residing within the gastrodermal tissues of host animals. Of particular concern are the consequences of bleaching of large numbers of reef-building scleractinian corals and hydrocorals. Published records of coral reef bleaching events from 1870 to the present suggest that the frequency (60 major events from 1979 to 1990), scale (co-occurrence in many coral reef regions and often over the bathymetric depth range of corals) and severity (>95% mortality in some areas) of recent bleaching disturbances are unprecedented in the scientific literature. The causes of small scale, isolated bleaching events can often be explained by particular stressors (e.g., temperature, salinity, light, sedimentation, aerial exposure and pollutants), but attempts to explain large scale bleaching events in terms of possible global change (e.g., greenhouse warming, increased UV radiation flux, deteriorating ecosystem health, or some combination of the above) have not been convincing. Attempts to relate the severity and extent of large scale coral reef bleaching events to particular causes have been hampered by a lack of (a) standardized methods to assess bleaching and (b) continuous, long-term data bases of environmental conditions over the periods of interest. An effort must be made to understand the impact of bleaching on the remainder of the reef community and the long-term effects on competition, predation, symbioses, bioerosion and substrate condition, all factors that can influence coral recruitment and reef recovery. If projected rates of sea warming are realized by mid to late AD 2000, i.e. a 2°C increase in high latitude coral seas, the upper thermal tolerance limits of many reef-building corals could be exceeded. Present evidence suggests that many corals would be unable to adapt

  14. Screening by coral green fluorescent protein (GFP)-like chromoproteins supports a role in photoprotection of zooxanthellae

    Science.gov (United States)

    Smith, E. G.; D'Angelo, C.; Salih, A.; Wiedenmann, J.

    2013-06-01

    Green fluorescent protein (GFP)-like pigments are responsible for the vivid colouration of many reef-building corals and have been proposed to act as photoprotectants. Their role remains controversial because the functional mechanism has not been elucidated. We provide direct evidence to support a photoprotective role of the non-fluorescent chromoproteins (CPs) that form a biochemically and photophysically distinct group of GFP-like proteins. Based on observations of Acropora nobilis from the Great Barrier Reef, we explored the photoprotective role of CPs by analysing five coral species under controlled conditions. In vitro and in hospite analyses of chlorophyll excitation demonstrate that screening by CPs leads to a reduction in chlorophyll excitation corresponding to the spectral properties of the specific CPs present in the coral tissues. Between 562 and 586 nm, the CPs maximal absorption range, there was an up to 50 % reduction of chlorophyll excitation. The screening was consistent for established and regenerating tissue and amongst symbiont clades A, C and D. Moreover, among two differently pigmented morphs of Acropora valida grown under identical light conditions and hosting subclade type C3 symbionts, high CP expression correlated with reduced photodamage under acute light stress.

  15. Genetic analysis of sunflower chlorophyll mutants

    International Nuclear Information System (INIS)

    Mashkina, E.V.; Guskov, E.P.

    2001-01-01

    The method of getting the chlorophyll mutations in sunflower was developed by Y.D. Beletskii in 1969 with the use of N-nitroso-N-methylurea (NMH). Certain concentrations of NMH are known to induce plastid mutations in growing seeds, and their yield depends on the duration of the exposure. The given work presented studies on the influence of rifampicin (R) and 2,4-dinitrophenol (DNP) on the genetic activity NMH, as an inductor of plastid and nuclear mutations

  16. Evaluation of Stony Coral Indicators for Coral Reef ...

    Science.gov (United States)

    Colonies of reef-building stony corals at 57 stations around St. Croix, U.S. Virgin Islands were characterized by species, size and percentage of living tissue. Taxonomic, biological and physical indicators of coral condition were derived from these measurements and assessed for their response to gradients of human disturbance. The purpose of the study was to identify indicators that could be used for regulatory assessments under authority of the Clean Water Act--this requires that indicators distinguish anthropogenic disturbances from natural variation. Stony coral indicators were tested for correlation with human disturbance across gradients located on three different sides of the island. At the most intensely disturbed location, five of eight primary indicators were highly correlated with distance from the source of disturbance: Coral taxa richness, average colony size, the coefficient of variation of colony size (an indicator of colony size heterogeneity), total topographic coral surface area, and live coral surface area. An additional set of exploratory indicators related to rarity, reproductive and spawning mode, and taxonomic identity were also screened for association with disturbance at the same location. For the other two locations, there were no significant changes in indicator values and therefore no discernible effects of human activity. Coral indicators demonstrated sufficient precision to detect levels of change that would be applicable in a regio

  17. Assessment of coral health in the coastal areas of the Persian Gulf

    Science.gov (United States)

    Kourandeh, Mehdi Bolouki; Nabavi, S. Mohammad Bagher; Sinaei, Mahmood

    2013-09-01

    In this study, Zooxanthellae density, chlorophyll a concentration, and mitotic index (MI) were measured in the coral Porites compressa obtained from coastal areas of the Persian Gulf in early February to September 2008. During the summer, zooxanthellae density declined by approximately 30% compared to the winter peak (3,607,849 ± 229,894, n = 15) and reached a minimum of 2,536,732 ± 169,776, n = 15. The highest value of chlorophyll a (0.828 ± 0.043 μg/cm2) was recorded in the south while the lowest (0.604 ± 0.048 μg/cm2) was measured in the north sampling site at the cold season. There was a higher level of MI in the warm season followed by cold > and temperate seasons. The MI were significantly higher (p < 0.05) in the warm and cold seasons in comparison with the temperate season. Differences in response may be attributed to the drastic seasonal temperature changes. However, the significant decline found in the north sampling site indicates that anthropogenic stressors may adversely affect coral P. compressa. These results imply that there were negative impacts on coral P. compressa in our study site.

  18. Variation in the composition of corals, fishes, sponges, echinoderms, ascidians, molluscs, foraminifera and macroalgae across a pronounced in-to-offshore environmental gradient in the Jakarta Bay-Thousand Islands coral reef complex.

    Science.gov (United States)

    Cleary, D F R; Polónia, A R M; Renema, W; Hoeksema, B W; Rachello-Dolmen, P G; Moolenbeek, R G; Budiyanto, A; Yahmantoro; Tuti, Y; Giyanto; Draisma, S G A; Prud'homme van Reine, W F; Hariyanto, R; Gittenberger, A; Rikoh, M S; de Voogd, N J

    2016-09-30

    Substrate cover, water quality parameters and assemblages of corals, fishes, sponges, echinoderms, ascidians, molluscs, benthic foraminifera and macroalgae were sampled across a pronounced environmental gradient in the Jakarta Bay-Thousand Islands reef complex. Inshore sites mainly consisted of sand, rubble and turf algae with elevated temperature, dissolved oxygen, pH and chlorophyll concentrations and depauperate assemblages of all taxa. Live coral cover was very low inshore and mainly consisted of sparse massive coral heads and a few encrusting species. Faunal assemblages were more speciose and compositionally distinct mid- and offshore compared to inshore. There were, however, small-scale differences among taxa. Certain midshore sites, for example, housed assemblages resembling those typical of the inshore environment but this differed depending on the taxon. Substrate, water quality and spatial variables together explained from 31% (molluscs) to 72% (foraminifera) of the variation in composition. In general, satellite-derived parameters outperformed locally measured parameters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Coral diseases and bleaching on Colombian Caribbean coral reefs.

    Science.gov (United States)

    Navas-Camacho, Raúl; Gil-Agudelo, Diego Luis; Rodríguez-Ramírez, Alberto; Reyes-Nivia, María Catalina; Garzón-Ferreira, Jaime

    2010-05-01

    Since 1998 the National Monitoring System for the Coral Reefs of Colombia (SIMAC) has monitored the occurrence of coral bleaching and diseases in some Colombian coral reefs (permanent stations at San Andres Island, Rosario Islands, Tayrona, San Bernardo Islands and Urabá). The main purpose is to evaluate their health status and to understand the factors that have been contributing to their decline. To estimate these occurrences, annual surveys in 126 permanent belt transects (10 x 2m) with different depth intervals (3-6 meters, 9-12 meters and 15-18 meters) are performed at all reef sites. Data from the 1998-2004 period, revealed that San Andrés Island had many colonies with diseases (38.9 colonies/m2), and Urabá had high numbers with bleaching (54.4 colonies/m2). Of the seven reported coral diseases studied, Dark Spots Disease (DSD), and White Plague Disease (WPD) were noteworthy because they occurred in all Caribbean monitored sites, and because of their high interannual infection incidence. Thirty five species of scleractinian corals were affected by at least one disease and a high incidence of coral diseases on the main reef builders is documented. Bleaching was present in 34 species. During the whole monitoring period, Agaricia agaricites and Siderastrea siderea were the species most severely affected by DSD and bleaching, respectively. Diseases on species such as Agaricia fragilis, A. grahamae, A. humilis, Diploria clivosa, Eusmilia fastigiata, Millepora complanata, and Mycetophyllia aliciae are recorded for first time in Colombia. We present bleaching and disease incidences, kinds of diseases, coral species affected, reef localities studied, depth intervals of surveys, and temporal (years) variation for each geographic area. This variation makes difficult to clearly determine defined patterns or general trends for monitored reefs. This is the first long-term study of coral diseases and bleaching in the Southwestern Caribbean, and one of the few long

  20. One-electron oxidation of photosynthetic pigments in micelles. Bacteriochlorophyll a, chlorophyll a, chlorophyll b, and pheophytin a

    International Nuclear Information System (INIS)

    Chauvet, J.P.

    1981-01-01

    Chlorophyll a, chlorophyll b, and bacteriochlorophyll a in aqueous micellar solutions of Trition X 100 (2%) are readily oxidized by pulse-radiolytically generated N 3 ., Br 2 - ., and (SCN) 2 - . radicals at nearly diffusion-controlled rates. The kinetic study suggests that pigment molecules occupy multiple sites in the micelle. Pheophytin a is only oxidized by N 3 . and Br 2 - . radicals. The absolute spectra and the molar extinction coefficients of chlorophyll a, bacteriochlorophyll a, chlorophyll b, and pheophytin a cations have been determined. The chlorophyll a cation has been observed in the presence of pigment aggregates

  1. Coral reproduction in Western Australia

    Science.gov (United States)

    Speed, Conrad W.; Babcock, Russ

    2016-01-01

    Larval production and recruitment underpin the maintenance of coral populations, but these early life history stages are vulnerable to extreme variation in physical conditions. Environmental managers aim to minimise human impacts during significant periods of larval production and recruitment on reefs, but doing so requires knowledge of the modes and timing of coral reproduction. Most corals are hermaphroditic or gonochoric, with a brooding or broadcast spawning mode of reproduction. Brooding corals are a significant component of some reefs and produce larvae over consecutive months. Broadcast spawning corals are more common and display considerable variation in their patterns of spawning among reefs. Highly synchronous spawning can occur on reefs around Australia, particularly on the Great Barrier Reef. On Australia’s remote north-west coast there have been fewer studies of coral reproduction. The recent industrial expansion into these regions has facilitated research, but the associated data are often contained within confidential reports. Here we combine information in this grey-literature with that available publicly to update our knowledge of coral reproduction in WA, for tens of thousands of corals and hundreds of species from over a dozen reefs spanning 20° of latitude. We identified broad patterns in coral reproduction, but more detailed insights were hindered by biased sampling; most studies focused on species of Acropora sampled over a few months at several reefs. Within the existing data, there was a latitudinal gradient in spawning activity among seasons, with mass spawning during autumn occurring on all reefs (but the temperate south-west). Participation in a smaller, multi-specific spawning during spring decreased from approximately one quarter of corals on the Kimberley Oceanic reefs to little participation at Ningaloo. Within these seasons, spawning was concentrated in March and/or April, and October and/or November, depending on the timing of

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

    Directory of Open Access Journals (Sweden)

    Ronaldo Ribeiro de Morais

    2007-10-01

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

  3. Crescimento e teores de clorofila em mudas de bananeira em função da supressão do pseudocaule, de doses de nitrogênio e de boro Growth and chlorophyll content of banana suckers in function of pseudostem suppression and doses of nitrogen and boron

    Directory of Open Access Journals (Sweden)

    Walter Esfrain Pereira

    2010-12-01

    plant. The data were submitted the variance analysis and of regression. The suppression in the pseudostem of the mother plant with elimination of the apical meristem of the rhizome increased the sucker number, with larger growth, except of the diameter of the rhizome which it reduced. In the plants with suppression, it reduced the sucker number which presented smaller growth. On the other hand, it increased the content of total chlorophyll. For the production of ‘Pacovan’ banana suckers, is recommended the suppression in the pseudostem of the mother plant with elimination of the meristem apical of the rhizome and the application of the N.

  4. Coral reef ecosystem

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Wafar, S.

    ), on submerged banks like Gave shani bank (13°24'N; 73°45'E) (Nair and Qasim 1978) andSidere~ko Bank (13°43.5' N; 73°42'E) (Rao 1972) and as stray individual units off Visakhapatnam (Bakus, G. personal communication) and Pondicherry (Ramesh, A. personal... communication). Fossil reefs, drowned as a result of the Holocene sea level rise, occur at 92, 85, 75 and 55 m depth along .. ~ !! ":2 0. ~ Figure 3.1 Graphical Representation of the SO-Box Model of a Caribbean Coral Reef Key: 1. Benthic producers. 2. Detritus...

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

    Science.gov (United States)

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

    2016-01-01

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

  6. The effectiveness of laser diode induction to Carica Papaya L. chlorophyll extract to be ROS generating in the photodynamic inactivation mechanisms for C.albicans biofilms

    International Nuclear Information System (INIS)

    Astuty, S Dewi; Baktir, A

    2017-01-01

    Research on the effectiveness of photo inactivation of C.albicans biofilms led by a-PDT system mediated by chlorophyll-diode-laser-induced was done. This research was done using in vitro technique in order to effectively determine chlorophyll extract of ROS-generated Carica Papaya L. using in situ technique. This technique induced laser diode on different dose and C. albicans with reduced degree. This research is a preliminary study in efforts to find anew sensitizer agent candidate made of chlorophyll extract and antifungal of Carica Papaya L. The effectiveness of eradication has been tested with MDA’s content and OD of biomass biofilms as well as analyzed using ANOVA and Tukey Test (α=0.05). The characteristic of chlorophyll extract of Carica Papaya L. has maximum absorptions on blue areas (λ max = 420 nm) and red areas (λ max = 670 nm). The MIC value of Carica Papaya L. ’s chlorophyll extract against C. albicans planktonic and biofilms cell is 63.8 μM and 31.9 μM respectively. The result shows that treatment using laser which was combined with chlorophyll extract is more effective than that with laser only or chlorophyll extract only. The treatment using laser combined with chlorophyll extract obtained more than 65% (α=0.05) (more than that of negative control) for P 2 L 1 group with OD 595 0.915. The MDA’s content showed that group of laser which was mediated with chlorophyll extract had larger values than group of laser or chlorophyll extract only. (paper)

  7. New perspectives on ecological mechanisms affecting coral recruitment on reefs

    NARCIS (Netherlands)

    Ritson-Williams, R.; Arnold, S.N.; Fogarty, N.D.; Steneck, R.S.; Vermeij, M.J.A.; Paul, V.J.

    2009-01-01

    Coral mortality has increased in recent decades, making coral recruitment more important than ever in sustaining coral reef ecosystems and contributing to their resilience. This review summarizes existing information on ecological factors affecting scleractinian coral recruitment. Successful

  8. Human activities threaten coral reefs

    International Nuclear Information System (INIS)

    Tveitdal, Svein; Bjoerke, Aake

    2002-01-01

    Research indicates that 58 per cent of the coral reefs of the world are threatened by human activities. Pollution and global heating represent some of the threats. Coral reefs just beneath the surface of the sea are very sensitive to temperature changes. Since 1979, mass death of coral reefs has been reported increasingly often. More than 1000 marine species live in the coral reefs, among these are one fourth of all marine species of fish. It is imperative that the coral reefs be preserved, as coastal communities all over the world depend on them as sources of food and as they are the raw materials for important medicines. The article discusses the threats to the coral reefs in general and does not single out any particular energy-related activity as the principal threat. For instance, the El-Nino phenomenon of the Pacific Ocean is probably involved in mass death of coral reefs and in the North Sea large parts of deep-water reefs have been crushed by heavy beam trawlers fishing for bottom fish

  9. Temporal variability of chlorophyll distribution in the Gulf of Mexico: bio-optical data from profiling floats

    Science.gov (United States)

    Pasqueron de Fommervault, Orens; Perez-Brunius, Paula; Damien, Pierre; Camacho-Ibar, Victor F.; Sheinbaum, Julio

    2017-12-01

    Chlorophyll concentration is a key oceanic biogeochemical variable. In the Gulf of Mexico (GOM), its distribution, which is mainly obtained from satellite surface observations and scarce in situ experiments, is still poorly understood. In 2011-2012, eight profiling floats equipped with biogeochemical sensors were deployed for the first time in the GOM and generated an unprecedented dataset that significantly increased the number of chlorophyll vertical distribution measurements in the region. The analysis of these data, once calibrated, permits us to reconsider the spatial and temporal variability of the chlorophyll concentration in the water column. At a seasonal scale, results confirm the surface signal seen by satellites, presenting maximum concentrations in winter and low values in summer. It is shown that the deepening of the mixed layer is the primary factor triggering the chlorophyll surface increase in winter. In the GOM, a possible interpretation is that this surface increase corresponds to a biomass increase. However, the present dataset suggests that the basin-scale climatological surface increase in chlorophyll content results from a vertical redistribution of subsurface chlorophyll and/or photoacclimation processes, rather than a net increase of biomass. One plausible explanation for this is the decoupling between the mixed-layer depth and the deep nutrient reservoir since mixed-layer depth only reaches the nitracline in sporadic events in the observations. Float measurements also provide evidence that the depth and the magnitude of the deep chlorophyll maximum is strongly controlled by the mesoscale variability, with higher chlorophyll biomass generally observed in cyclones rather than anticyclones.

  10. Combining X-Ray Fluorescence and Magnetic Techniques to Quantify Elemental Concentrations in Coral Cores from Belize

    Science.gov (United States)

    Goldfarb, L. A.; Kingsley, C.; Urbalejo, A. A.; Hangsterfer, A.; Gee, J. S.; Carilli, J.; Feinberg, J. M.; Mitra, R.; Bhattacharya, A.; Field, D.

    2017-12-01

    Caribbean coral reefs are some of the most threatened marine ecosystems in the world. Research suggest that environmental stressors of local origin, such as sediment run off, can reduce the resilience of these reefs to global threats such as ocean warming. Material trapped in coral skeletons can provide information on the sources of particulate matter in the ocean ecosystem. Despite the importance of quantifying sources and types of materials trapped in corals, the research community is yet to fully develop techniques that allow accurate representation of trapped matter, which is potentially a major source of metal content in reef building coral skeletons. The dataset presented here is a progress and combination of two works presented at American Geophysical Union 2016 Fall Meeting; In this research, we explore the efficacy of X-Ray Fluorescence (XRF), a widely used tool in environmental studies (but generally not in corals), to estimate detrital metal content in coral cores collected from four locations near Belize, with varying degrees of impact from coastal processes. Four coral cores together cover a period of 1862-2006. Trace, major and minor metal content from these cores have been well-studied using solution-based ICP-MS, providing us with the unique opportunity to test the efficacy of XRF technique in characterizing metal content in these coral cores. We have measured more than 50 metals using XRF every two millimeters along slabs removed from the middle of a coral core spanning to characterize materials present in coral skeletons. We compare the results from XRF to elemental concentrations reported from solution-based ICP-MS. Furthermore, we also compare our XRF data to magnetic measurements we have made in these same coral cores. Overall, it appears that the non-destructive XRF technique is a viable supplement to the ICP-MS in determining sediment and metal content in coral cores, and may be particularly helpful for assessing resistant phases such as

  11. 75 FR 39917 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Coral and Coral Reefs off the...

    Science.gov (United States)

    2010-07-13

    ... the Caribbean, Gulf of Mexico, and South Atlantic; Coral and Coral Reefs off the Southern Atlantic... regulations implementing the Fishery Management Plan for Coral, Coral Reefs, and Live/Hardbottom Habitat of... Cancer Institute (http:// [[Page 39918

  12. Cu toxicity on growth and chlorophyll-a of Chaetoceros sp.

    Science.gov (United States)

    Puspitasari, R.; Suratno; Purbonegoro, T.; Agustin, A. T.

    2018-02-01

    Phytoplankton is a primary producer in marine aquatic ecosystem. Their sensitivity to metal makes them important to study to predict the environmental impact of pollution. Copper is an essential nutrient for aquatic life as micronutrients on an organism but toxic at high levels. The focus of this study was to assess the toxicity of copper to Chaetoceros sp. on growth and chlorophyll-a content. The result shows that inhibition concentration (IC50) of copper on the microalgae, Chaetoceros sp. was 30.25 μg L-1. Growth of Chaetoceros sp. decreased 16.84% in 16 μg L-1 and 81.97% in 44 μg L-1. Chlorophyll-a content decreased dramatically at 44 μg L-1 compared to control. Increase of the cell size, deformation of cell wall and loss of setae were observed at higher concentration of copper.

  13. Local stressors reduce coral resilience to bleaching.

    Science.gov (United States)

    Carilli, Jessica E; Norris, Richard D; Black, Bryan A; Walsh, Sheila M; McField, Melanie

    2009-07-22

    Coral bleaching, during which corals lose their symbiotic dinoflagellates, typically corresponds with periods of intense heat stress, and appears to be increasing in frequency and geographic extent as the climate warms. A fundamental question in coral reef ecology is whether chronic local stress reduces coral resistance and resilience from episodic stress such as bleaching, or alternatively promotes acclimatization, potentially increasing resistance and resilience. Here we show that following a major bleaching event, Montastraea faveolata coral growth rates at sites with higher local anthropogenic stressors remained suppressed for at least 8 years, while coral growth rates at sites with lower stress recovered in 2-3 years. Instead of promoting acclimatization, our data indicate that background stress reduces coral fitness and resilience to episodic events. We also suggest that reducing chronic stress through local coral reef management efforts may increase coral resilience to global climate change.

  14. Fungi and their role in corals and coral reef ecosystems

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Ravindran, J.

    fungal hyphae have on corals, their mechanism of penetration and the role their enzymes play in this process. 3.2. Fungi as pathogens in reef ecosystems Besides natural disasters and climate warming, diseases have contributed to coral decline... defence mechanisms against predation, biofouling, diseases, environmental perturbations and other stressors. These chemicals are either synthesized by the organisms themselves or their endobiontic microorganisms. If these valuable compounds...

  15. Physical and chemical characteristics of Vietnamese natural corals used as substitutes for bone grafts

    International Nuclear Information System (INIS)

    Tran Cong Toai; To Phuong Vu; Tran Bac Hai; Doan Binh

    1999-01-01

    Coral has been used as substitutes for bone grafts in France and the United State of American. In Vietnam, research on coral has been done at the Biomaterial Research Laboratory, The University Training Centre since 1994. Among the studies are the determination of physical and chemical characteristics of natural coral blocks obtained by the scientists of the NhaTrang Maritime Institute. We found that it was quite necessary to establish a standard formula for processing coral as biomaterial graft. The selected coral was cut into blocks approximately 1x1x1 cm or 1x1x2 cm and cleaned. We measured the density, porous rate, water loading speed (at room temperature and at boiled temperature with low pressure, mechanical strength and content of soluble protein, chitosan in coral rods. (1140 samples of three types of corals). The density of Porites australiensis was heavier than that of Porites lutea. But, Porites lutea has more porous rate than Porites australiensis. This experiment has also showed that mechanical strength of Porites australiensis was harder than that of Porites lutea. To measure the water loading speed, the coral rods were treated at boiled temperature with low pressure versus at room temperature. We found that the water loading speed of Porites australiensis at boiled temperature was faster than that at room temperature. Porites lutea and Montastrea annuligera showed as the same result. The efficiency of water loading rate is quite low approximately 116 - 121 % for 45 minutes at room temperature versus 135 - 155 % for only I 0 minutes at boiled temperature with low pressure. We measured the content of soluble protein by both Lowry and Biuret methods, the content of soluble protein after washing with 0.9% sodium chloride, 1210 degree C, 60 minutes is very low (below limit of tests). The content of chitosan from dried coral rods treated with HCI 36 - 38 % and NAOH 0.01N is about 0.1 - 0.6 %. Our study determined some physical and chemical characteristics

  16. Comparative study of polycyclic aromatic hydrocarbons in coral tissues and the ambient sediments from Kenting National Park, Taiwan

    International Nuclear Information System (INIS)

    Ko, Fung-Chi; Chang, Chiung-Wen; Cheng, Jing-O.

    2014-01-01

    Surface sediments and corals (Acropora sp. and Montipora sp.) from the coastline of Kenting were analyzed in 2009 and 2010 for content levels of polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry. The total PAH concentrations (t-PAH) in corasls (143–1715 ng g −1 dw) were significantly higher than in the ambient sediments (2–59 ng g −1 dw) indicating the bioaccumulation of PAHs in corals. The spatial and seasonal variation in PAH levels suggested that land-loaded contaminants may be the main source of PAHs in the Kenting coral reefs. Based on molecular indices, PAHs were substantially of petroleum origin. The major PAH components were phenanthrene, pyrene and fluorine, but PAH congeners in corals and sediments still have characteristic composition patterns which would be altered by the bio/accumulation mechanisms. Further study is essential to assess and understand the impacts of these chemicals on coral reefs. Highlights: • PAH concentrations in Kenting coral reefs ranked minor in the worldwide comparison. • Isomeric ratios of PAHs suggested an important contribution of petrogenic sources. • PAHs have characteristic composition patterns which would be altered by the bio/accumulation mechanisms. • Higher levels of PAHs were found in coral tissues than in sediments (bioaccumulation). • Coral body burdens of PAHs were significantly correlated to adjacent sediments only at the areas with higher levels of PAHs. -- PAH levels in coral tissues were higher than in adjacent sediments (bioaccumulation)

  17. Contribution of Polyphenol Oxidation, Chlorophyll and Vitamin C Degradation to the Blackening of Piper nigrum L.

    Science.gov (United States)

    Gu, Fenglin; Huang, Feifei; Wu, Guiping; Zhu, Hongying

    2018-02-09

    Black pepper ( Piper nigrum L.) is the most widely used spice in the world. Blackening is considered to be beneficial and important in the processing of black pepper because it contributes to its color and flavor. The purpose of this paper is to investigate polyphenol oxidation as well as the chlorophyll and vitamin C (VC) degradation in the blackening of Piper nigrum L. Black pepper was produced by four methods, and changes in polyphenols, chlorophyll and VC were studied by high performance liquid chromatography (HPLC) and ultraviolet-visible and visible (UV-Vis) spectrophotometry. The results show that polyphenol oxidase activity significantly decreased during the preparation of black pepper, and the concentrations of phenolic compounds, VC, and chlorophyll a and b also significantly decreased. Polyphenol oxidation and chlorophyll and VC degradation contribute to the blackening. A crude extract of phenolic compounds from black pepper was prepared by the system solvent method. The greater the polarity of the extraction solvent, the higher the extraction rates of the phenolic compounds and the total phenol content. Pepper phenolic compounds were analyzed by HPLC analysis.

  18. Contribution of Polyphenol Oxidation, Chlorophyll and Vitamin C Degradation to the Blackening of Piper nigrum L.

    Directory of Open Access Journals (Sweden)

    Fenglin Gu

    2018-02-01

    Full Text Available Black pepper (Piper nigrum L. is the most widely used spice in the world. Blackening is considered to be beneficial and important in the processing of black pepper because it contributes to its color and flavor. The purpose of this paper is to investigate polyphenol oxidation as well as the chlorophyll and vitamin C (VC degradation in the blackening of Piper nigrum L. Black pepper was produced by four methods, and changes in polyphenols, chlorophyll and VC were studied by high performance liquid chromatography (HPLC and ultraviolet-visible and visible (UV-Vis spectrophotometry. The results show that polyphenol oxidase activity significantly decreased during the preparation of black pepper, and the concentrations of phenolic compounds, VC, and chlorophyll a and b also significantly decreased. Polyphenol oxidation and chlorophyll and VC degradation contribute to the blackening. A crude extract of phenolic compounds from black pepper was prepared by the system solvent method. The greater the polarity of the extraction solvent, the higher the extraction rates of the phenolic compounds and the total phenol content. Pepper phenolic compounds were analyzed by HPLC analysis.

  19. The role of floridoside in osmoadaptation of coral-associated algal endosymbionts to high-salinity conditions

    KAUST Repository

    Ochsenkuhn, Michael A.; Rö thig, Till; D’ Angelo, Cecilia; Wiedenmann, Jö rg; Voolstra, Christian R.

    2017-01-01

    occur in the Persian/Arabian Gulf and the Red Sea, which also represent the most saline coral habitats. We studied whether Symbiodinium alter their metabolite content in response to high-salinity environments. We found that Symbiodinium cells exposed

  20. Salt stress change chlorophyll fluorescence in mango

    Directory of Open Access Journals (Sweden)

    Cicero Cartaxo de Lucena

    2012-12-01

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

  1. An extended PROSPECT: Advance in the leaf optical properties model separating total chlorophylls into chlorophyll a and b.

    Science.gov (United States)

    Zhang, Yao; Huang, Jingfeng; Wang, Fumin; Blackburn, George Alan; Zhang, Hankui K; Wang, Xiuzhen; Wei, Chuanwen; Zhang, Kangyu; Wei, Chen

    2017-07-25

    The PROSPECT leaf optical model has, to date, well-separated the effects of total chlorophyll and carotenoids on leaf reflectance and transmittance in the 400-800 nm. Considering variations in chlorophyll a:b ratio with leaf age and physiological stress, a further separation of total plant-based chlorophylls into chlorophyll a and chlorophyll b is necessary for advanced monitoring of plant growth. In this study, we present an extended version of PROSPECT model (hereafter referred to as PROSPECT-MP) that can combine the effects of chlorophyll a, chlorophyll b and carotenoids on leaf directional hemispherical reflectance and transmittance (DHR and DHT) in the 400-800 nm. The LOPEX93 dataset was used to evaluate the capabilities of PROSPECT-MP for spectra modelling and pigment retrieval. The results show that PROSPECT-MP can both simultaneously retrieve leaf chlorophyll a and b, and also performs better than PROSPECT-5 in retrieving carotenoids concentrations. As for the simulation of DHR and DHT, the performances of PROSPECT-MP are similar to that of PROSPECT-5. This study demonstrates the potential of PROSPECT-MP for improving capabilities of remote sensing of leaf photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) and for providing a framework for future refinements in the modelling of leaf optical properties.

  2. Teores de clorofila determinados por medidor portátil e sua relação com formas de nitrogênio em folhas de tomateiro cultivados em dois tipos de solo Relations among chlorophyll contents determined by a portable meter and nitrogen forms in leaves of tomatoes cultivated in two soil types

    Directory of Open Access Journals (Sweden)

    TADEU GRACIOLLI GUIMARÃES

    1999-01-01

    das leituras obtidas no medidor SPAD, permitiu o ajuste de equação linear (CP = -77,233 + 3,54725** SPAD R2 = 0,766.This work aimed to determine chlorophyll concentrations of tomato (Lycopersicon esculentum Mill. plants cv. Santa Clara fertilized with five nitrogen (N rates by means of conventional laboratory methodology and by the SPAD-502 portable chlorophyll meter. The relationship between chlorophyll and N values was determined by these two methods. Tomato plants were grown in pots with a clay soil classified as Cambic Red-Yellow Podsol (CRP and a sand-course soil classified as Quartzic Sand (QS, and received five N rates (25, 125, 225, 325 and 425 mg. dm-3 sidedressed as nutrient solutions. At the onset of 3rd cluster anthesis, chlorophyll concentrations were determined in leaves opposite to this cluster by the portable chlorophyll meter SPAD-502 and at laboratory by Arnon's methodology. NO3-N was determined in petiole sap and in dry matter, while NO3-N, org-N and total-N were determined in leaf blade dry matter. Chlorophyll concentrations increased with N rates irrespective of method of determination, in both soils. Critical levels in soils CRP and QS were, respectively, 77.3 and 83.6 mg. cm-2 by laboratory methodology and 45.5 and 43.8 SPAD units by the portable meter. Correlation coefficients of chlorophyll concentrations with top dry weight and N forms were greater for the SPAD method. Both methods of chlorophyll determination presented greatest correlation with sap NO3-N in soil CRP, and with org-N and total-N in soil QS. The estimative of chlorophyll concentrations (laboratory method by means of SPAD readings allowed the adjustment of a linear equation (CP = -77.233 + 3.54725** SPAD R2 = 0.766.

  3. Analysis of Biophysical, Optical and Genetic Diversity of DoD Coral Reef Communities Using Advanced Fluorescence and Molecular Biology Techniques (Addendum)

    Science.gov (United States)

    2011-08-01

    coloration and by a decrease in photosynthetic efficiency that resembles coral bleaching . For instance, early reports referred to Vibrio infection...in coral as “bacterial bleaching ”. We examined the physiological mechanisms and fluorescence signatures of YBD using laboratory cultures of isolated...pigment content (a sign similar to coral bleaching ), cell degeneration and lysis. The exposure to Vibrio was accompanied by a marked reduction (by

  4. The Magnesium Chelation Step in Chlorophyll Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gregory L. Dilworth, Ph.D Chemical Sciences, Geosciences and Biosciences Division Office of Basis Energy Sciences, greg.dilworth@science.doe.gov

    2001-01-17

    The progress described in this report encompasses work supported by DOE grant DE-FG09-89ER13989 for the period 2/15/92 to the present 6/14/94. The goals of the project were to continue investigating the enzymology of Mg-chelatase and to investigate the co-regulation of heme and chlorophyll formation in intact plastids. During this period the laboratory had additional support (two years) from USDA to investigate heme metabolism in chloroplasts. This report is arranged so that the progress is described by reference to manuscripts which are published, under review or in preparation.

  5. Coral Reef Protection Implementation Plan

    National Research Council Canada - National Science Library

    Lobel, Lisa

    2000-01-01

    This document identify policies and actions to implement the Department of Defense's responsibilities under Executive Order 13089 on Coral Reef Protection, and are a requirement of the interim Task...

  6. Advancing Ocean Monitoring Near Coral Reefs

    Science.gov (United States)

    Heron, Scott F.; Steinberg, Craig R.; Heron, Mal L.; Mantovanelli, Alessandra; Jaffrés, Jasmine B. D.; Skirving, William J.; McAllister, Felicity; Rigby, Paul; Wisdom, Daniel; Bainbridge, Scott

    2010-10-01

    Corals, the foundation of tropical marine ecosystems, exist in a symbiotic relationship with zooxanthellae (algae). The corals obtain much of their energy by consuming compounds derived from photosynthesis by these microorganisms; the microorganisms, which reside in the coral tissue, in turn use waste products from the corals to sustain photosynthesis. This symbiosis is very sensitive to subtle changes in environment, such as increased ocean acidity, temperature, and light. When unduly stressed, the colorful algae are expelled from the corals, causing the corals to “bleach” and potentially die [e.g., van Oppen and Lough, 2009].

  7. Contrasting effect of dark-chilling on chloroplast structure and arrangement of chlorophyll-protein complexes in pea and tomato : Plants with a different susceptibility to non-freezing temperature

    NARCIS (Netherlands)

    Garstka, Maciej; Venema, Jan Henk; Rumak, Izabela; Gieczewska, Katarzyna; Rosiak, Malgorzata; Koziol-Lipinska, Joanna; Kierdaszuk, Borys; Vredenberg, Wim J.; Mostowska, Agnieszka

    2007-01-01

    The effect of dark-chilling and subsequent photoactivation on chloroplast structure and arrangements of chlorophyll-protein complexes in thylakoid membranes was studied in chilling-tolerant (CT) pea and in chilling-sensitive (CS) tomato. Dark-chilling did not influence chlorophyll content and Chl

  8. Contrasting effect of dark-chilling on chloroplast structure and arrangement of chlorophyll-protein complexes in pea and tomato: plants with a different susceptibility to non-freezing temperature

    NARCIS (Netherlands)

    Garstka, M.; Venema, J.H.; Rumak, I.; Gieczewska, K.; Rosiak, M.; Koziol-Lipinska, J.; Vredenberg, W.J.; Mostowska, A.

    2007-01-01

    The effect of dark-chilling and subsequent photoactivation on chloroplast structure and arrangements of chlorophyll-protein complexes in thylakoid membranes was studied in chilling-tolerant (CT) pea and in chilling-sensitive (CS) tomato. Dark-chilling did not influence chlorophyll content and Chl

  9. Lil3 dimerization and chlorophyll binding in Arabidopsis thaliana.

    Science.gov (United States)

    Mork-Jansson, Astrid Elisabeth; Gargano, Daniela; Kmiec, Karol; Furnes, Clemens; Shevela, Dmitriy; Eichacker, Lutz Andreas

    2015-10-07

    The two-helix light harvesting like (Lil) protein Lil3 belongs to the family of chlorophyll binding light harvesting proteins of photosynthetic membranes. A function in tetrapyrrol synthesis and stabilization of geranylgeraniol reductase has been shown. Lil proteins contain the chlorophyll a/b-binding motif; however, binding of chlorophyll has not been demonstrated. We find that Lil3.2 from Arabidopsis thaliana forms heterodimers with Lil3.1 and binds chlorophyll. Lil3.2 heterodimerization (25±7.8 nM) is favored relative to homodimerization (431±59 nM). Interaction of Lil3.2 with chlorophyll a (231±49 nM) suggests that heterodimerization precedes binding of chlorophyll in Arabidopsis thaliana. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2011-02-01

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

  11. Coral Sr-U Thermometry

    Science.gov (United States)

    DeCarlo, T. M.; Gaetani, G. A.; Cohen, A. L.; Foster, G. L.; Alpert, A.; Stewart, J.

    2016-12-01

    Coral skeletons archive the past two millennia of climate variability in the oceans with unrivaled temporal resolution. However, extracting accurate temperature information from coral skeletons is confounded by "vital effects", which often override the temperature dependence of geochemical proxies. Here, we present a new approach to coral paleothermometry based on results of abiogenic precipitation experiments interpreted within a framework provided by a quantitative model of the coral biomineralization process. We conducted laboratory experiments to test the temperature and carbonate chemistry controls on abiogenic partitioning of Sr/Ca and U/Ca between aragonite and seawater, and we modeled the sensitivity of skeletal composition to processes occurring at the site of calcification. The model predicts that temperature can be accurately reconstructed from coral skeleton by combining Sr/Ca and U/Ca ratios into a new proxy, Sr-U. We tested the model predictions with measured Sr/Ca and U/Ca ratios of fourteen Porites sp. corals collected from the tropical Pacific Ocean and the Red Sea, with a subset also analyzed using the boron isotope (δ11B) pH proxy. Observed relationships among Sr/Ca, U/Ca, and δ11B agree with model predictions, indicating that the model accounts for the key features of the coral biomineralization process. We calibrated Sr-U to instrumental temperature records and found that it captures 93% of mean annual variability (26-30 °C) and predicts temperature within 0.5 °C (1 σ). Conversely, Sr/Ca alone has an error of prediction of 1 °C and often diverges from observed temperature by 3 °C or more. Many of the problems afflicting Sr/Ca - including offsets among neighboring corals and decouplings from temperature during coral stress events - are reconciled by Sr-U. By accounting for the influence of the coral biomineralization process, the Sr-U thermometer may offer significantly improved reliability for reconstructing ocean temperatures from coral

  12. Biological Responses of the Coral Montastraea annularis to the Removal of Filamentous Turf Algae

    Science.gov (United States)

    Cetz-Navarro, Neidy P.; Espinoza-Avalos, Julio; Hernández-Arana, Héctor A.; Carricart-Ganivet, Juan P.

    2013-01-01

    Coral reef degradation increases coral interactions with filamentous turf algae (FTA) and macroalgae, which may result in chronic stress for the corals. We evaluated the effects of short (2.5 month) and long (10 month) periods of FTA removal on tissue thickness (TT), zooxanthellae density (ZD), mitotic index (MI), and concentration of chlorophyll a (Chl a) in Montastraea annularis at the beginning and end of gametogenesis. Ramets (individual lobes within a colony) consistently surrounded by FTA and ramets surrounded by crustose coralline algae (CCA) were used as controls. FTA removal reduced coral stress, indicated by increased TT and ZD and lower MI. The measured effects were similar in magnitude for the short and long periods of algal removal. Ramets were more stressed at the end of gametogenesis compared with the beginning, with lower ZD and Chl a cm−2, and higher MI. However, it was not possible to distinguish the stress caused by the presence of FTA from that caused by seasonal changes in seawater temperature. Ramets surrounded by CCA showed less stress in comparison with ramets surrounded by FTA: with higher TT, Chl a cm−2 and ZD, and lower MI values. Coral responses indicated that ramets with FTA suffered the most deleterious effects and contrasted with those measured in ramets surrounded by CCA. According to published studies and our observations, there could be at least six mechanisms associated to FTA in the stress caused to M. annularis by FTA. Owing to the high cover of FTA (in contrast to macroalgae and CCA) in the Caribbean, the chronic stress, the overgrowth and mortality that this functional algal group can cause on M. annularis species complex, a further decline of this important reef-building coral in the Caribbean is expected. PMID:23372774

  13. Biological responses of the coral Montastraea annularis to the removal of filamentous turf algae.

    Directory of Open Access Journals (Sweden)

    Neidy P Cetz-Navarro

    Full Text Available Coral reef degradation increases coral interactions with filamentous turf algae (FTA and macroalgae, which may result in chronic stress for the corals. We evaluated the effects of short (2.5 month and long (10 month periods of FTA removal on tissue thickness (TT, zooxanthellae density (ZD, mitotic index (MI, and concentration of chlorophyll a (Chl a in Montastraea annularis at the beginning and end of gametogenesis. Ramets (individual lobes within a colony consistently surrounded by FTA and ramets surrounded by crustose coralline algae (CCA were used as controls. FTA removal reduced coral stress, indicated by increased TT and ZD and lower MI. The measured effects were similar in magnitude for the short and long periods of algal removal. Ramets were more stressed at the end of gametogenesis compared with the beginning, with lower ZD and Chl a cm(-2, and higher MI. However, it was not possible to distinguish the stress caused by the presence of FTA from that caused by seasonal changes in seawater temperature. Ramets surrounded by CCA showed less stress in comparison with ramets surrounded by FTA: with higher TT, Chl a cm(-2 and ZD, and lower MI values. Coral responses indicated that ramets with FTA suffered the most deleterious effects and contrasted with those measured in ramets surrounded by CCA. According to published studies and our observations, there could be at least six mechanisms associated to FTA in the stress caused to M. annularis by FTA. Owing to the high cover of FTA (in contrast to macroalgae and CCA in the Caribbean, the chronic stress, the overgrowth and mortality that this functional algal group can cause on M. annularis species complex, a further decline of this important reef-building coral in the Caribbean is expected.

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  15. Viruses: agents of coral disease?

    Science.gov (United States)

    Davy, S K; Burchett, S G; Dale, A L; Davies, P; Davy, J E; Muncke, C; Hoegh-Guldberg, O; Wilson, W H

    2006-03-23

    The potential role of viruses in coral disease has only recently begun to receive attention. Here we describe our attempts to determine whether viruses are present in thermally stressed corals Pavona danai, Acropora formosa and Stylophora pistillata and zoanthids Zoanthus sp., and their zooxanthellae. Heat-shocked P. danai, A. formosa and Zoanthus sp. all produced numerous virus-like particles (VLPs) that were evident in the animal tissue, zooxanthellae and the surrounding seawater; VLPs were also seen around heat-shocked freshly isolated zooxanthellae (FIZ) from P. danai and S. pistillata. The most commonly seen VLPs were tail-less, hexagonal and about 40 to 50 nm in diameter, though a diverse range of other VLP morphotypes (e.g. rounded, rod-shaped, droplet-shaped, filamentous) were also present around corals. When VLPs around heat-shocked FIZ from S. pistillata were added to non-stressed FIZ from this coral, they resulted in cell lysis, suggesting that an infectious agent was present; however, analysis with transmission electron microscopy provided no clear evidence of viral infection. The release of diverse VLPs was again apparent when flow cytometry was used to enumerate release by heat-stressed A. formosa nubbins. Our data support the infection of reef corals by viruses, though we cannot yet determine the precise origin (i.e. coral, zooxanthellae and/or surface microbes) of the VLPs seen. Furthermore, genome sequence data are required to establish the presence of viruses unequivocally.

  16. "Super-quenching" state protects Symbiodinium from thermal stress - Implications for coral bleaching.

    Science.gov (United States)

    Slavov, Chavdar; Schrameyer, Verena; Reus, Michael; Ralph, Peter J; Hill, Ross; Büchel, Claudia; Larkum, Anthony W D; Holzwarth, Alfred R

    2016-06-01

    The global rise in sea surface temperatures causes regular exposure of corals to high temperature and high light stress, leading to worldwide disastrous coral bleaching events (loss of symbiotic dinoflagellates (Symbiodinium) from reef-building corals). Our picosecond chlorophyll fluorescence experiments on cultured Symbiodinium clade C cells exposed to coral bleaching conditions uncovered the transformations of the alga's photosynthetic apparatus (PSA) that activate an extremely efficient non-photochemical "super-quenching" mechanism. The mechanism is associated with a transition from an initially heterogeneous photosystem II (PSII) pool to a homogeneous "spillover" pool, where nearly all excitation energy is transferred to photosystem I (PSI). There, the inherently higher stability of PSI and high quenching efficiency of P(700)(+) allow dumping of PSII excess excitation energy into heat, resulting in almost complete cessation of photosynthetic electron transport (PET). This potentially reversible "super-quenching" mechanism protects the PSA against destruction at the cost of a loss of photosynthetic activity. We suggest that the inhibition of PET and the consequent inhibition of organic carbon production (e.g. sugars) in the symbiotic Symbiodinium provide a trigger for the symbiont expulsion, i.e. bleaching. Copyright © 2016. Published by Elsevier B.V.

  17. Coral population trajectories, increased disturbance and management intervention: A sensitivity analysis

    KAUST Repository

    Riegl, Bernhard; Berumen, Michael L.; Bruckner, Andrew

    2013-01-01

    Coral reefs distant from human population were sampled in the Red Sea and one-third showed degradation by predator outbreaks (crown-of-thorns-starfish=COTS observed in all regions in all years) or bleaching (1998, 2010). Models were built to assess future trajectories. They assumed variable coral types (slow/fast growing), disturbance frequencies (5,10,20years), mortality (equal or not), and connectivity (un/connected to un/disturbed community). Known disturbances were used to parameterize models. Present and future disturbances were estimated from remote-sensing chlorophyll and temperature data. Simulations and sensitivity analysis suggest community resilience at >20-year disturbance frequency, but degradation at higher frequency. Trajectories move from fast-grower to slow-grower dominance at intermediate disturbance frequency, then again to fast-grower dominance. A similar succession was observed in the field: Acropora to Porites to Stylophora/Pocillopora dominance on shallow reefs, and a transition from large poritids to small faviids on deep reefs. Synthesis and application: Even distant reefs are impacted by global changes. COTS impacts and bleaching were key driver of coral degradation, coral population decline could be reduced if these outbreaks and bleaching susceptibility were managed by maintaining water quality and by other interventions. Just leaving reefs alone, seems no longer a satisfactory option. 2013 The Authors. Ecology and Evolution.

  18. Coral population trajectories, increased disturbance and management intervention: A sensitivity analysis

    KAUST Repository

    Riegl, Bernhard

    2013-03-07

    Coral reefs distant from human population were sampled in the Red Sea and one-third showed degradation by predator outbreaks (crown-of-thorns-starfish=COTS observed in all regions in all years) or bleaching (1998, 2010). Models were built to assess future trajectories. They assumed variable coral types (slow/fast growing), disturbance frequencies (5,10,20years), mortality (equal or not), and connectivity (un/connected to un/disturbed community). Known disturbances were used to parameterize models. Present and future disturbances were estimated from remote-sensing chlorophyll and temperature data. Simulations and sensitivity analysis suggest community resilience at >20-year disturbance frequency, but degradation at higher frequency. Trajectories move from fast-grower to slow-grower dominance at intermediate disturbance frequency, then again to fast-grower dominance. A similar succession was observed in the field: Acropora to Porites to Stylophora/Pocillopora dominance on shallow reefs, and a transition from large poritids to small faviids on deep reefs. Synthesis and application: Even distant reefs are impacted by global changes. COTS impacts and bleaching were key driver of coral degradation, coral population decline could be reduced if these outbreaks and bleaching susceptibility were managed by maintaining water quality and by other interventions. Just leaving reefs alone, seems no longer a satisfactory option. 2013 The Authors. Ecology and Evolution.

  19. Chlorophyll-a specific volume scattering function of phytoplankton.

    Science.gov (United States)

    Tan, Hiroyuki; Oishi, Tomohiko; Tanaka, Akihiko; Doerffer, Roland; Tan, Yasuhiro

    2017-06-12

    Chlorophyll-a specific light volume scattering functions (VSFs) by cultured phytoplankton in visible spectrum range is presented. Chlorophyll-a specific VSFs were determined based on the linear least squares method using a measured VSFs with different chlorophyll-a concentrations. We found obvious variability of it in terms of spectral and angular shapes of VSF between cultures. It was also presented that chlorophyll-a specific scattering significantly affected on spectral variation of the remote sensing reflectance, depending on spectral shape of b. This result is useful for developing an advance algorithm of ocean color remote sensing and for deep understanding of light in the sea.

  20. Natural disease resistance in threatened staghorn corals.

    Directory of Open Access Journals (Sweden)

    Steven V Vollmer

    Full Text Available Disease epidemics have caused extensive damage to tropical coral reefs and to the reef-building corals themselves, yet nothing is known about the abilities of the coral host to resist disease infection. Understanding the potential for natural disease resistance in corals is critically important, especially in the Caribbean where the two ecologically dominant shallow-water corals, Acropora cervicornis and A. palmata, have suffered an unprecedented mass die-off due to White Band Disease (WBD, and are now listed as threatened under the US Threatened Species Act and as critically endangered under the IUCN Red List criteria. Here we examine the potential for natural resistance to WBD in the staghorn coral Acropora cervicornis by combining microsatellite genotype information with in situ transmission assays and field monitoring of WBD on tagged genotypes. We show that six percent of staghorn coral genotypes (3 out of 49 are resistant to WBD. This natural resistance to WBD in staghorn corals represents the first evidence of host disease resistance in scleractinian corals and demonstrates that staghorn corals have an innate ability to resist WBD infection. These resistant staghorn coral genotypes may explain why pockets of Acropora have been able to survive the WBD epidemic. Understanding disease resistance in these corals may be the critical link to restoring populations of these once dominant corals throughout their range.

  1. THE CONDITION OF CORAL REEFS IN SOUTH FLORIDA (2000) USING CORAL DISEASE AND BLEACHING AS INDICATORS

    Science.gov (United States)

    The destruction for coral reef habitats is occurring at unprecedented levels. Coral disease epizootics in the Southwestern Atlantic have lead to coral replacement by turf algae, prompting a call to classify some coral species as endangered. In addition, a massive bleaching event ...

  2. The magnesium chelation step in chlorophyll biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, J.D.

    1991-01-01

    The biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins and lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX. Insertion of iron leads to heme, while insertion of magnesium leads to chlorophyll. The Mg-chelatase from intact cucumber chloroplasts has been characterized with regard to substrate specificity, regulation, ATP requirement, and a requirement for intact chloroplasts. Mg-chelatase was isolated from maize, barley and peas and characterized in order to circumvent the intact chloroplast requirement of cucumber Mg-chelatase. Pea Mg-chelatase activity is higher than cucumber Mg-chelatase activity, and lacks the requirement for intact chloroplasts. Studies on isolated pea Mg-chelatase have shown more cofactors are required for the reaction than are seen with ferrochelatase, indicating a greater opportunity for regulatory control of this pathway. Two of the cofactors are proteins, and there appears to be a requirement for a protease-sensitive component which is outside the outer envelope. We are developing a continuous spectrophotometric assay for Mg-chelatase activity, and an assay for free heme which has shown heme efflux from intact chloroplasts. 18 refs. (MHB)

  3. Stereoelectronic properties of aggregated chlorophyll systems

    Energy Technology Data Exchange (ETDEWEB)

    Christoffersen, R. E.; Maggiora, G. M.

    1979-09-01

    During the first nine months of the current contract, significant progress has occurred in several areas. All SCF CI studies of the singlet and triplet states of the neutral molecules Et-Chl a, Et-Pheo a, Et-BChl a, and Et-BPheo a, and the doublet states of the ..pi..-cation radicals Et-Chl a/sup +/. and Et-BChl a/sup +/. have now been completed. In addition, SCF CI calculations on BPheo a/sup -/. indicate that ..pi..-anion radicals can also be studied using the present approach. Similar work on a number of other ..pi..-cation and ..pi..-anion radicals is currently underway. Preliminary SCF CI studies have also been completed for benzoquinone and dihydroquinone, and studies on benzoquinone/sup -/. should be completed by the end of this year. The development and characterization of an empirical potential function is nearly complete, and data from selected systems is summarized. Implementation of a more efficient, quadratically convergent energy minimization procedure is also being carried out. This procedure should make it possible to study the geometry and properties of dimeric chlorophyll systems as well as various ligand-chlorophyll systems. Developmental work is continuing on the direct calculation of optical rotatory strengths.

  4. Coral calcification and ocean acidification

    Science.gov (United States)

    Jokiel, Paul L.; Jury, Christopher P.; Kuffner, Ilsa B.

    2016-01-01

    Over 60 years ago, the discovery that light increased calcification in the coral plant-animal symbiosis triggered interest in explaining the phenomenon and understanding the mechanisms involved. Major findings along the way include the observation that carbon fixed by photosynthesis in the zooxanthellae is translocated to animal cells throughout the colony and that corals can therefore live as autotrophs in many situations. Recent research has focused on explaining the observed reduction in calcification rate with increasing ocean acidification (OA). Experiments have shown a direct correlation between declining ocean pH, declining aragonite saturation state (Ωarag), declining [CO32_] and coral calcification. Nearly all previous reports on OA identify Ωarag or its surrogate [CO32] as the factor driving coral calcification. However, the alternate “Proton Flux Hypothesis” stated that coral calcification is controlled by diffusion limitation of net H+ transport through the boundary layer in relation to availability of dissolved inorganic carbon (DIC). The “Two Compartment Proton Flux Model” expanded this explanation and synthesized diverse observations into a universal model that explains many paradoxes of coral metabolism, morphology and plasticity of growth form in addition to observed coral skeletal growth response to OA. It is now clear that irradiance is the main driver of net photosynthesis (Pnet), which in turn drives net calcification (Gnet), and alters pH in the bulk water surrounding the coral. Pnet controls [CO32] and thus Ωarag of the bulk water over the diel cycle. Changes in Ωarag and pH lag behind Gnet throughout the daily cycle by two or more hours. The flux rate Pnet, rather than concentration-based parameters (e.g., Ωarag, [CO3 2], pH and [DIC]:[H+] ratio) is the primary driver of Gnet. Daytime coral metabolism rapidly removes DIC from the bulk seawater. Photosynthesis increases the bulk seawater pH while providing the energy that drives

  5. Biosynthesis of Chlorophyll a in a Purple Bacterial Phototroph and Assembly into a Plant Chlorophyll-Protein Complex.

    Science.gov (United States)

    Hitchcock, Andrew; Jackson, Philip J; Chidgey, Jack W; Dickman, Mark J; Hunter, C Neil; Canniffe, Daniel P

    2016-09-16

    Improvements to photosynthetic efficiency could be achieved by manipulating pigment biosynthetic pathways of photosynthetic organisms in order to increase the spectral coverage for light absorption. The development of organisms that can produce both bacteriochlorophylls and chlorophylls is one way to achieve this aim, and accordingly we have engineered the bacteriochlorophyll-utilizing anoxygenic phototroph Rhodobacter sphaeroides to make chlorophyll a. Bacteriochlorophyll and chlorophyll share a common biosynthetic pathway up to the precursor chlorophyllide. Deletion of genes responsible for the bacteriochlorophyll-specific modifications of chlorophyllide and replacement of the native bacteriochlorophyll synthase with a cyanobacterial chlorophyll synthase resulted in the production of chlorophyll a. This pigment could be assembled in vivo into the plant water-soluble chlorophyll protein, heterologously produced in Rhodobacter sphaeroides, which represents a proof-of-principle for the engineering of novel antenna complexes that enhance the spectral range of photosynthesis.

  6. Effects of Protection and Sediment Stress on Coral Reefs in Saint Lucia.

    Science.gov (United States)

    Bégin, Chantale; Schelten, Christiane K; Nugues, Maggy M; Hawkins, Julie; Roberts, Callum; Côté, Isabelle M

    2016-01-01

    The extent to which Marine Protected Areas (MPAs) benefit corals is contentious. On one hand, MPAs could enhance coral growth and survival through increases in herbivory within their borders; on the other, they are unlikely to prevent disturbances, such as terrestrial runoff, that originate outside their boundaries. We examined the effect of spatial protection and terrestrial sediment on the benthic composition of coral reefs in Saint Lucia. In 2011 (10 to 16 years after MPAs were created), we resurveyed 21 reefs that had been surveyed in 2001 and analyzed current benthic assemblages as well as changes in benthic cover over that decade in relation to protection status, terrestrial sediment influence (measured as the proportion of terrigenous material in reef-associated sediment) and depth. The cover of all benthic biotic components has changed significantly over the decade, including a decline in coral and increase in macroalgae. Protection status was not a significant predictor of either current benthic composition or changes in composition, but current cover and change in cover of several components were related to terrigenous content of sediment deposited recently. Sites with a higher proportion of terrigenous sediment had lower current coral cover, higher macroalgal cover and greater coral declines. Our results suggest that terrestrial sediment is an important factor in the recent degradation of coral reefs in Saint Lucia and that the current MPA network should be complemented by measures to reduce runoff from land.

  7. Effects of Protection and Sediment Stress on Coral Reefs in Saint Lucia.

    Directory of Open Access Journals (Sweden)

    Chantale Bégin

    Full Text Available The extent to which Marine Protected Areas (MPAs benefit corals is contentious. On one hand, MPAs could enhance coral growth and survival through increases in herbivory within their borders; on the other, they are unlikely to prevent disturbances, such as terrestrial runoff, that originate outside their boundaries. We examined the effect of spatial protection and terrestrial sediment on the benthic composition of coral reefs in Saint Lucia. In 2011 (10 to 16 years after MPAs were created, we resurveyed 21 reefs that had been surveyed in 2001 and analyzed current benthic assemblages as well as changes in benthic cover over that decade in relation to protection status, terrestrial sediment influence (measured as the proportion of terrigenous material in reef-associated sediment and depth. The cover of all benthic biotic components has changed significantly over the decade, including a decline in coral and increase in macroalgae. Protection status was not a significant predictor of either current benthic composition or changes in composition, but current cover and change in cover of several components were related to terrigenous content of sediment deposited recently. Sites with a higher proportion of terrigenous sediment had lower current coral cover, higher macroalgal cover and greater coral declines. Our results suggest that terrestrial sediment is an important factor in the recent degradation of coral reefs in Saint Lucia and that the current MPA network should be complemented by measures to reduce runoff from land.

  8. Bayesian object-based estimation of LAI and chlorophyll from a simulated Sentinel-2 top-of-atmosphere radiance image

    NARCIS (Netherlands)

    Laurent, V.C.E.; Schaepman, M.E.; Verhoef, W.; Weyermann, J.; Chavez Oyanadel, R.O.

    2014-01-01

    Leaf area index (LAI) and chlorophyll content (Cab) are important vegetation variables which can be monitored using remote sensing (RS). Physically-based approaches have higher transferability and are therefore better suited than empirically-based approaches for estimating LAI and Cab at global

  9. Do chestnut, northern red, and white oak germinant seedlings respond similary to light treatments? II. Gas exchange and chlorophyll responses

    Science.gov (United States)

    Joanne Rebbeck; Amy Scherzer; Kurt. Gottschalk

    2012-01-01

    Understanding differences in physiological and growth strategies in low-light environments among upland oak species may help managers address the challenges of oaks' poor regeneration. Gas exchange and chlorophyll content were measured for northern red oak (Quercus rubra L.), chestnut oak (Quercus prinus L.), and white oak (...

  10. Zooxanthellae Harvested by Ciliates Associated with Brown Band Syndrome of Corals Remain Photosynthetically Competent▿

    Science.gov (United States)

    Ulstrup, Karin E.; Kühl, Michael; Bourne, David G.

    2007-01-01

    Brown band syndrome is a new coral affliction characterized by a local accumulation of yet-unidentified ciliates migrating as a band along the branches of coral colonies. In the current study, morphologically intact zooxanthellae (= Symbiodinium) were observed in great numbers inside the ciliates (>50 dinoflagellates per ciliate). Microscale oxygen measurements and variable chlorophyll a fluorescence analysis along with microscopic observations demonstrated that zooxanthellae within the ciliates are photosynthetically competent and do not become compromised during the progression of the brown band zone. Zooxanthellae showed similar trends in light acclimation in a comparison of rapid light curve and steady-state light curve measures of variable chlorophyll a fluorescence. Extended light exposure of steady-state light curves resulted in higher quantum yields of photosystem II. The brown band tissue exhibited higher photosynthetically active radiation absorptivity, indicating more efficient light absorption due to a higher density of zooxanthellae in the ciliate-dominated zone. This caused relatively higher gross photosynthesis rates in the zone with zooxanthella-containing ciliates compared to healthy coral tissue. The observation of photosynthetically active intracellular zooxanthellae in the ciliates suggests that the latter can benefit from photosynthates produced by ingested zooxanthellae and from photosynthetic oxygen production that alleviates diffusion limitation of oxic respiration in the densely populated brown band tissue. It remains to be shown whether the zooxanthellae form a stable symbiotic association with the ciliate or are engulfed incidentally during grazing on coral tissue and then maintained as active inside the ciliate for a period before being digested and replaced by new zooxanthellae. PMID:17259357

  11. Zooxanthellae harvested by ciliates associated with brown band syndrome of corals remain photosynthetically competent.

    Science.gov (United States)

    Ulstrup, Karin E; Kühl, Michael; Bourne, David G

    2007-03-01

    Brown band syndrome is a new coral affliction characterized by a local accumulation of yet-unidentified ciliates migrating as a band along the branches of coral colonies. In the current study, morphologically intact zooxanthellae (= Symbiodinium) were observed in great numbers inside the ciliates (>50 dinoflagellates per ciliate). Microscale oxygen measurements and variable chlorophyll a fluorescence analysis along with microscopic observations demonstrated that zooxanthellae within the ciliates are photosynthetically competent and do not become compromised during the progression of the brown band zone. Zooxanthellae showed similar trends in light acclimation in a comparison of rapid light curve and steady-state light curve measures of variable chlorophyll a fluorescence. Extended light exposure of steady-state light curves resulted in higher quantum yields of photosystem II. The brown band tissue exhibited higher photosynthetically active radiation absorptivity, indicating more efficient light absorption due to a higher density of zooxanthellae in the ciliate-dominated zone. This caused relatively higher gross photosynthesis rates in the zone with zooxanthella-containing ciliates compared to healthy coral tissue. The observation of photosynthetically active intracellular zooxanthellae in the ciliates suggests that the latter can benefit from photosynthates produced by ingested zooxanthellae and from photosynthetic oxygen production that alleviates diffusion limitation of oxic respiration in the densely populated brown band tissue. It remains to be shown whether the zooxanthellae form a stable symbiotic association with the ciliate or are engulfed incidentally during grazing on coral tissue and then maintained as active inside the ciliate for a period before being digested and replaced by new zooxanthellae.

  12. Studies on the performance of TiO{sub 2} thin films as protective layer to chlorophyll in Ocimum tenuiflorum L from UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Malliga, P. [Department of Physics, V.V.Vanniaperumal College for Women, Virudhunagar – 626001 (India); Selvi, B. Karunai [Department of Botany, V.V.Vanniaperumal College for Women, Virudhunagar – 626001 (India); Pandiarajan, J.; Prithivikumaran, N. [Nanoscience Lab, Department of Physics, VHNSN College, Virudhunagar – 626001 (India); Neyvasagam, K., E-mail: srineyvas@yahoo.co.in [Department of Physics, The Madura College, Madurai - 625011 (India)

    2015-06-24

    Thin films of TiO{sub 2} were prepared on glass substrates using sol-gel dip coating technique. The films with 10 coatings were prepared and annealed at temperatures 350°C, 450°C and 550°C for 1 hour in muffle furnace. The annealed films were characterized by X – Ray diffraction (XRD), UV – Visible, AFM, Field Effect Scanning Electron Microscopy (FESEM) and EDAX studies. Chlorophyll has many health benefits due to its structural similarity to human blood and its good chelating ability. It has antimutagenic and anticarcinogenic properties. UV light impairs photosynthesis and reduces size, productivity, and quality in many of the crop plant species. Increased exposure of UV light reduces chlorophyll contents a, b and total content in plants. Titanium Dioxide (TiO{sub 2}) is a wide band gap semiconductor and efficient light harvester. TiO{sub 2} has strong UltraViolet (UV) light absorbing capability. Here, we have studied the performance of TiO{sub 2} thin films as a protective layer to the chlorophyll contents present in medicinal plant, tulsi (Ocimum tenuiflorum L) from UV radiation. The study reveals that crystallite size increases, transmittance decreases and chlorophyll contents increases with increase in annealing temperature. This study showed that TiO{sub 2} thin films are good absorber of UV light and protect the chlorophyll contents a, b and total content in medicinal plants.

  13. Studies on the performance of TiO2 thin films as protective layer to chlorophyll in Ocimum tenuiflorum L from UV radiation

    International Nuclear Information System (INIS)

    Malliga, P.; Selvi, B. Karunai; Pandiarajan, J.; Prithivikumaran, N.; Neyvasagam, K.

    2015-01-01

    Thin films of TiO 2 were prepared on glass substrates using sol-gel dip coating technique. The films with 10 coatings were prepared and annealed at temperatures 350°C, 450°C and 550°C for 1 hour in muffle furnace. The annealed films were characterized by X – Ray diffraction (XRD), UV – Visible, AFM, Field Effect Scanning Electron Microscopy (FESEM) and EDAX studies. Chlorophyll has many health benefits due to its structural similarity to human blood and its good chelating ability. It has antimutagenic and anticarcinogenic properties. UV light impairs photosynthesis and reduces size, productivity, and quality in many of the crop plant species. Increased exposure of UV light reduces chlorophyll contents a, b and total content in plants. Titanium Dioxide (TiO 2 ) is a wide band gap semiconductor and efficient light harvester. TiO 2 has strong UltraViolet (UV) light absorbing capability. Here, we have studied the performance of TiO 2 thin films as a protective layer to the chlorophyll contents present in medicinal plant, tulsi (Ocimum tenuiflorum L) from UV radiation. The study reveals that crystallite size increases, transmittance decreases and chlorophyll contents increases with increase in annealing temperature. This study showed that TiO 2 thin films are good absorber of UV light and protect the chlorophyll contents a, b and total content in medicinal plants

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

    Science.gov (United States)

    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 (SIF 760 ) and the apparent fluorescence yield (SIF 760 /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 SIF 760 /a and Φ PSII 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, Φ PSII and SIF 760 /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 (Φ PSII and SIF 760 /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

  15. Revealing Holobiont Structure and Function of Three Red Sea Deep-Sea Corals

    KAUST Repository

    Yum, Lauren

    2014-12-01

    Deep-sea corals have long been regarded as cold-water coral; however a reevaluation of their habitat limitations has been suggested after the discovery of deep-sea coral in the Red Sea where temperatures exceed 20˚C. To gain further insight into the biology of deep-sea corals at these temperatures, the work in this PhD employed a holotranscriptomic approach, looking at coral animal host and bacterial symbiont gene expression in Dendrophyllia sp., Eguchipsammia fistula, and Rhizotrochus sp. sampled from the deep Red Sea. Bacterial community composition was analyzed via amplicon-based 16S surveys and cultured bacterial strains were subjected to bioprospecting in order to gauge the pharmaceutical potential of coralassociated microbes. Coral host transcriptome data suggest that coral can employ mitochondrial hypometabolism, anaerobic glycolysis, and surface cilia to enhance mass transport rates to manage the low oxygen and highly oligotrophic Red Sea waters. In the microbial community associated with these corals, ribokinases and retron-type reverse transcriptases are abundantly expressed. In its first application to deep-sea coral associated microbial communities, 16S-based next-generation sequencing found that a single operational taxonomic unit can comprise the majority of sequence reads and that a large number of low abundance populations are present, which cannot be visualized with first generation sequencing. Bioactivity testing of selected bacterial isolates was surveyed over 100 cytological parameters with high content screening, covering several major organelles and key proteins involved in a variety of signaling cascades. Some of these cytological profiles were similar to those of several reference pharmacologically active compounds, which suggest that the bacteria isolates produce compounds with similar mechanisms of action as the reference compounds. The sum of this work offers several mechanisms by which Red Sea deep-sea corals cope with environmental

  16. Light Intensity-Dependent Modulation of Chlorophyll b Biosynthesis and Photosynthesis by Overexpression of Chlorophyllide a Oxygenase in Tobacco1[C][OA

    Science.gov (United States)

    Biswal, Ajaya K.; Pattanayak, Gopal K.; Pandey, Shiv S.; Leelavathi, Sadhu; Reddy, Vanga S.; Govindjee; Tripathy, Baishnab C.

    2012-01-01

    Chlorophyll b is synthesized by the oxidation of a methyl group on the B ring of a tetrapyrrole molecule to a formyl group by chlorophyllide a oxygenase (CAO). The full-length CAO from Arabidopsis (Arabidopsis thaliana) was overexpressed in tobacco (Nicotiana tabacum) that grows well at light intensities much higher than those tolerated by Arabidopsis. This resulted in an increased synthesis of glutamate semialdehyde, 5-aminolevulinic acid, magnesium-porphyrins, and chlorophylls. Overexpression of CAO resulted in increased chlorophyll b synthesis and a decreased chlorophyll a/b ratio in low light-grown as well as high light-grown tobacco plants; this effect, however, was more pronounced in high light. The increased potential of the protochlorophyllide oxidoreductase activity and chlorophyll biosynthesis compensated for the usual loss of chlorophylls in high light. Increased chlorophyll b synthesis in CAO-overexpressed plants was accompanied not only by an increased abundance of light-harvesting chlorophyll proteins but also of other proteins of the electron transport chain, which led to an increase in the capture of light as well as enhanced (40%–80%) electron transport rates of photosystems I and II at both limiting and saturating light intensities. Although the quantum yield of carbon dioxide fixation remained unchanged, the light-saturated photosynthetic carbon assimilation, starch content, and dry matter accumulation increased in CAO-overexpressed plants grown in both low- and high-light regimes. These results demonstrate that controlled up-regulation of chlorophyll b biosynthesis comodulates the expression of several thylakoid membrane proteins that increase both the antenna size and the electron transport rates and enhance carbon dioxide assimilation, starch content, and dry matter accumulation. PMID:22419827

  17. Status of coral reefs of India

    Digital Repository Service at National Institute of Oceanography (India)

    Muley, E.V.; Venkataraman, K.; Alfred, J.R.B.; Wafar, M.V.M.

    and economic significance of coral reefs and the threat perceptions, Government of India has initiated measures for their intensive conservation and management. Present paper deals with ecological status of coral reefs in the country and various national...

  18. Elkhorn and Staghorn Corals Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for elkhorn coral (Acropora palmata) and staghorn coral (A. cervicornis) as designated by 73 FR 72210, November 26, 2008,...

  19. Deep-Sea Soft Coral Habitat Suitability

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Deep-sea corals, also known as cold water corals, create complex communities that provide habitat for a variety of invertebrate and fish species, such as grouper,...

  20. Deep-Sea Stony Coral Habitat Suitability

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Deep-sea corals, also known as cold water corals, create complex communities that provide habitat for a variety of invertebrate and fish species, such as grouper,...

  1. Coral Reef Watch, Hotspots, 50 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Coral Reef Watch provides Coral Bleaching hotspot maps derived from NOAA's Polar Operational Environmental Satellites (POES). This data provides global area...

  2. Chlorophyll evaluation methods in Brachiaria brizantha brs Piatã added with poultry litter compost

    Directory of Open Access Journals (Sweden)

    Alexandre Antonio Pasqualini

    2013-12-01

    Full Text Available One of the major limitations for pastures high production is the low fertility of tropical soils. In general, the nutrient reposition through chemical fertilizers increases the cost of production and can unbalance the plant besides the environment pollution. Recycling solid residues from agribusiness is a sustainable alternative for farmers. Among the residues, the poultry litter (PL aerobically fermented is a very good bio fertilizer for pastures. The Piatã Grass (Brachiaria brizantha is a new option for the pasture market and can be used for bovine, equine or ovine. The fast diagnosis of the nutritional stage of this plant, based upon portable methods as the Dualex, measuring leaf light reflectance is a practical alternative.  By this way,  it is possible to offer to the herd high nutritional food, correcting eventual shortage, mainly nitrogen. Nitrogen nutrition is directely related to chlorophyll content in the leaf blade. This study aimed to verify the effects of doses of PL over total chlorophyll, in comparison to two methods of evaluation: Dualex Scientific 4.0 and Spectrophotometer Analysis according to Lichtenthaler & Wellburn (1983. The experiment was conducted in greenhouse conditions, at IZ, Nova Odessa, with a Haplortox soil, between May and July, 2013. Treatments consisted of five compost doses (PL: 0, 20, 40, 60 and 120 Mg ha-1, with the following chemical composition (%: 2.88 of N, 3.85 of P2O5, 2.50 of K2O, 9.06 of Ca and 1.16 of Mg. The experimental design was on randomized blocks with five replications. Data were analyzed using the GLM procedure of the SAS program. Chlorophyll data were taken from the third medium of the leaf blade from a third of the expanded leaf from the apical using the Dualex. At the same time, samples were harvested for the Spectrophotometer analyses according to methodology described by Lichtenthaler & Wellburn (1983. Total Chlorophyll amounts were increased with the higher doses of PL, adjusting

  3. Coral diseases and bleaching on Colombian Caribbean coral reefs

    Directory of Open Access Journals (Sweden)

    Raúl Navas-Camacho

    2010-05-01

    Full Text Available Since 1998 the National Monitoring System for the Coral Reefs of Colombia (SIMAC has monitored the occurrence of coral bleaching and diseases in some Colombian coral reefs (permanent stations at San Andres Island, Rosario Islands, Tayrona, San Bernardo Islands and Urabá. The main purpose is to evaluate their health status and to understand the factors that have been contributing to their decline. To estimate these occurrences, annual surveys in 126 permanent belt transects (10x2m with different depth intervals (3-6 meters, 9-12 meters and 15-18 meters are performed at all reef sites. Data from the 1998-2004 period, revealed that San Andrés Island had many colonies with diseases (38.9 colonies/m2, and Urabá had high numbers with bleaching (54.4 colonies/m2. Of the seven reported coral diseases studied, Dark Spots Disease (DSD, and White Plague Disease (WPD were noteworthy because they occurred in all Caribbean monitored sites, and because of their high interannual infection incidence. Thirty five species of scleractinian corals were affected by at least one disease and a high incidence of coral diseases on the main reef builders is documented. Bleaching was present in 34 species. During the whole monitoring period, Agaricia agaricites and Siderastrea siderea were the species most severely affected by DSD and bleaching, respectively. Diseases on species such as Agaricia fragilis, A.grahamae, A. humilis, Diploria clivosa, Eusmilia fastigiata, Millepora complanata, and Mycetophyllia aliciae are recorded for first time in Colombia. We present bleaching and disease incidences, kinds of diseases, coral species affected, reef localities studied, depth intervals of surveys, and temporal (years variation for each geographic area. This variation makes difficult to clearly determine defined patterns or general trends for monitored reefs. This is the first long-term study of coral diseases and bleaching in the Southwestern Caribbean, and one of the few

  4. Coastal nutrification and coral health at Porto Seguro reefs, Brazil

    Science.gov (United States)

    Costa, O.; Attrill, M.; Nimmo, M.

    2003-04-01

    Human activities have substantially increased the natural flux of nutrients to coastal systems worldwide. In Brazilian reefs, all major stresses (sedimentation, overfishing, tourism-related activities and nutrification) are human induced. To assess nutrification levels in Brazilian coastal reefs, measurements of the distribution patterns of nutrients and chlorophyll concentrations were conducted in three nearshore and offshore reefs with distinct nutrient inputs along the south coast of Bahia State. Seawater and porewater samples were analysed for soluble reactive phosphorus, total oxidised nitrogen and reactive silica. Benthic surveys were performed at all sites to investigate the relationships between benthic community composition and nutrient and chlorophyll concentrations. Sampling was undertaken in dry and rainy seasons. Results of both seawater and porewater nutrient measurements revealed the occurrence of consistent spatial and temporal patterns. An inshore-offshore gradient reflects the occurrence of land-based point sources, with significant amount of nutrients being delivered by human activities on the coast (untreated sewage and groundwater seepage). Another spatial gradient is related to distance from a localized source of pollution (an urban settlement without sewerage treatment) with two nearshore reefs presenting distinct nutrient and chlorophyll concentrations. Seasonal variations suggest that submarine groundwater discharge (SGD) is the primary source of nutrients for the coastal reefs during rainy season. The data also suggests that the SGD effect is not restricted to nearshore reefs, and may be an important factor controlling the differences between landward and seaward sides on the offshore reef. Benthic community assessment revealed that turf alga is the dominant group in all studied reefs and that zoanthids are the organisms most adapted to take advantage of nutrient increase in coastal areas. At nearshore reefs, there was a negative

  5. Geochemical study of coral skeletons from the Puerto Morelos Reef, southeastern Mexico

    Science.gov (United States)

    Kasper-Zubillaga, Juan J.; Armstrong-Altrin, John S.; Rosales-Hoz, Leticia

    2014-12-01

    Geochemical analyses in coral skeletons have been used as a proxy of marine environmental conditions and to understand the mechanisms of adsorption of chemical elements into the coral skeletons and growth forms. However, little attention has been given to show the possible differences in the growth rates of corals based upon major, trace, rare earth element and microprobe analyses to examine the physical-chemical conditions influencing those differences. Our goal is to show how branch and fan corals incorporate elements into their skeletons comparing them with their coral growth rates. We determine the development of the skeletons of two branching (Acropora palmata, Acropora cervicornis) and one fan shaped (Gorgonia ventalina) colonies in the Puerto Morelos Reef, southeastern Mexico based upon geochemical data and the influence of terrigenous input into the species. Mg and Sr concentrations were the most statistically significant elements among the species studied suggesting that Mg concentration in Gorgonia ventalina is probably not linked to its growth rate. Mn content in the sea water is adsorbed by the three corals during past growth rates during high rainfall events. Sr concentration may be associated with the growth rate of Acropora palmata. Little differences in the growth rate in Acropora palmata may be associated with low rates of calcitization, negligible changes in the Sr concentration and little influence of temperature and water depth in its growth. Trace elements like Cr, Co, Ni and V adsorbed by the corals are influenced by natural concentration of these elements in the sea-water. Rare earth elements in the corals studied suggests abundant inorganic ions CO32- with variable pH in modern shallow well-oxygenated sea water. Lack of terrigenous input seawards is supported by geochemical, geomorphological and biological evidences. This study is an example of how geochemical data are useful to observe the differences in environmental conditions related to

  6. First record of multi-species synchronous coral spawning from Malaysia

    Directory of Open Access Journals (Sweden)

    Alvin Chelliah

    2015-02-01

    Full Text Available Knowledge about the timing and synchrony of coral spawning has important implications for both the ecology and management of coral reef ecosystems. Data on the timing of spawning and extent of synchrony, however, are still lacking for many coral reefs, particularly from equatorial regions and from locations within the coral triangle. Here we present the first documentation of a multi-species coral spawning event from reefs around Pulau Tioman, Peninsular Malaysia, a popular diving and tourist destination located on the edge of the coral triangle. At least 8 coral species from 3 genera (Acropora, Montipora and Porites participated in multi-species spawning over five nights in April 2014, between two nights before and two nights after the full moon. In addition, two Acropora species were witnessed spawning one night prior to the full moon in October 2014. While two of the Acropora species that reproduced in April (A. millepora and A. nasuta exhibited highly synchronous spawning (100% of sampled colonies, two other common species (A. hyacinthus and A. digitifera did not contain visible eggs in the majority of colonies sampled (i.e., <15% of colonies in either April or October, suggesting that these species spawn at other times of the year. To the best of our knowledge, this is the first detailed documented observation of multi-species coral spawning from reefs in Malaysia. These data provide further support for the contention that this phenomenon is a feature of all speciose coral assemblages, including equatorial reefs. More research is needed, however, to determine the seasonal cycles and extent of spawning synchrony on these reefs and elsewhere in Malaysia.

  7. 40 CFR 230.44 - Coral reefs.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Coral reefs. 230.44 Section 230.44... Aquatic Sites § 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually of calcareous... organisms present in growing portions of the reef. (b) Possible loss of values: The discharge of dredged or...

  8. An optimal thermal condition for maximal chlorophyll extraction

    Directory of Open Access Journals (Sweden)

    Fu Jia-Jia

    2017-01-01

    Full Text Available This work describes an environmentally friendly process for chlorophyll extraction from bamboo leaves. Shaking water bath and ultrasound cleaner are adopted in this technology, and the influence of temperature of the water bath and ultrasonic cleaner is evaluated. Results indicated that there is an optimal condition for maximal yield of chlorophyll.

  9. Regional ocean-colour chlorophyll algorithms for the Red Sea

    KAUST Repository

    Brewin, Robert J.W.; Raitsos, Dionysios E.; Dall'Olmo, Giorgio; Zarokanellos, Nikolaos; Jackson, Thomas; Racault, Marie-Fanny; Boss, Emmanuel S.; Sathyendranath, Shubha; Jones, Burton; Hoteit, Ibrahim

    2015-01-01

    an ocean-colour model for the Red Sea, parameterised to data collected during the Tara Oceans expedition, that estimates remote-sensing reflectance as a function of chlorophyll concentration. We used the Red Sea model to tune the standard chlorophyll

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

    NARCIS (Netherlands)

    Suhartanto, M.R.

    2002-01-01

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

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

    NARCIS (Netherlands)

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

    2009-01-01

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

  12. Dinitrogen fixation in a unicellular chlorophyll d-containing cyanobacterium

    NARCIS (Netherlands)

    Pfreundt, U.; Stal, L.J.; Voss, B.; Hess, W.R.

    2012-01-01

    Marine cyanobacteria of the genus Acaryochloris are the only known organisms that use chlorophyll d as a photosynthetic pigment. However, based on chemical sediment analyses, chlorophyll d has been recognized to be widespread in oceanic and lacustrine environments. Therefore it is highly relevant to

  13. Influence of ambient sulphur dioxide on chlorophyll

    International Nuclear Information System (INIS)

    Shahare, C.B.; Varshney, C.K.

    1995-01-01

    For the evaluation of the injury due to SO 2 from Indraprashtha (IP) Thermal Power Plant, eight species of trees were selected. Experiment was divided in two sections. Section one include transplanted tree saplings of Bauhinia variegata, Delonix regia, Flcus benghalensis, Putranjiwa roxburghii, Morus indica, Polyalthia longifolia, Leucaena leucocephala and Tabernaemontana coronaria. Here one set of plants was transplanted to polluted site of IP and other set was maintained at non polluted site of Jawaharlal Nehru University (Ecological Nursery). Second section of the study have naturally growing trees of the same species in the vicinity of the transplanted plants. Findings of the present study show that tree species were not safe at polluted site. Maximum chlorophyll reduction occurred in Bauhinia variegata, that is 32.05% (transplanted saplings). In naturally growing trees up to 35.70% reduction was seen in B. variegata. (author). 11 refs., 2 tabs

  14. Phytohormone and Light Regulation of Chlorophyll Degradation

    Directory of Open Access Journals (Sweden)

    Xiaoyu Zhu

    2017-11-01

    Full Text Available Degreening, due to the net loss of chlorophyll (Chl, is the most prominent symptom during the processes of leaf senescence, fruit ripening, and seed maturation. Over the last decade or so, extensive identifications of Chl catabolic genes (CCGs have led to the revelation of the biochemical pathway of Chl degradation. As such, exploration of the regulatory mechanism of the degreening process is greatly facilitated. During the past few years, substantial progress has been made in elucidating the regulation of Chl degradation, particularly via the mediation of major phytohormones' signaling. Intriguingly, ethylene and abscisic acid's signaling have been demonstrated to interweave with light signaling in mediating the regulation of Chl degradation. In this review, we briefly summarize this progress, with an effort on providing a framework for further investigation of multifaceted and hierarchical regulations of Chl degradation.

  15. CORAL REEFS. Genomic determinants of coral heat tolerance across latitudes.

    Science.gov (United States)

    Dixon, Groves B; Davies, Sarah W; Aglyamova, Galina A; Meyer, Eli; Bay, Line K; Matz, Mikhail V

    2015-06-26

    As global warming continues, reef-building corals could avoid local population declines through "genetic rescue" involving exchange of heat-tolerant genotypes across latitudes, but only if latitudinal variation in thermal tolerance is heritable. Here, we show an up-to-10-fold increase in odds of survival of coral larvae under heat stress when their parents come from a warmer lower-latitude location. Elevated thermal tolerance was associated with heritable differences in expression of oxidative, extracellular, transport, and mitochondrial functions that indicated a lack of prior stress. Moreover, two genomic regions strongly responded to selection for thermal tolerance in interlatitudinal crosses. These results demonstrate that variation in coral thermal tolerance across latitudes has a strong genetic basis and could serve as raw material for natural selection. Copyright © 2015, American Association for the Advancement of Science.

  16. The magnesium chelation step in chlorophyll biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, J.

    1990-11-01

    In photosynthetic organisms, the biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins, and various lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX (Proto). Insertion of iron leads to the formation of hemes, while insertion of magnesium is the first step unique to chlorophyll formation. This project is directed toward identifying the enzyme(s) responsible for magnesium chelation and elucidating the mechanism which regulates the flux of precursors through the branch point enzymes in isolated chloroplasts. Using intact chloroplasts from greening cucumber cotyledons, we have confirmed the ATP requirement for Mg-Proto formation. Use of non-hydrolyzable ATP analogs, uncouplers and ionophores has led to the conclusions that ATP hydrolysis is necessary, but that this hydrolysis is not linked to the requirement for membrane intactness by transmembrane ion gradients or electrical potentials. The enzyme(s) are flexible with respect to the porphyrin substrate specificity, accepting porphyrins with -vinyl, -ethyl, or -H substituents at the 2 and 4 positions. The activity increases approximately four-fold during greening. Possible physiological feedback inhibitors such as heme, protochlorophyllide, and chlorophyllide had no specific effect on the activity. The activity has now been assayed in barely, corn and peas, with the system from peas almost ten-fold more active than the cucumber system. Work is continuing in pea chloroplasts with the development of a continuous assay and investigation of the feasibility of characterizing an active, organelle-free preparation. 6 figs.

  17. Portable plant chlorophyll fluorimeter based on blue LED rapid induced technology

    Science.gov (United States)

    Zheng, Yibo; Mi, Ting; Zhang, Lei; Zhao, Jun

    2018-01-01

    Fluorimeter is an effective device for detecting chlorophyll a content in plants. In order to realize real-time nondestructive detection of plant blades, a camera based fluorescence instrument based on two color mirrors has been developed. The blue light LED is used as the excitation light source, and the lens is used for shaping and focusing the excitation light to ensure the excitation intensity and uniform illumination of the light source. The device uses a 45 degree two color mirror to separate the chlorophyll a excited light path and the fluorescence receiving light path. Finally, the fluorescent signal is collected by the silicon photocell, and the signal is processed by the circuit to transmit the digital information to the display. Through the analysis of the experimental data, the device has the advantages of small size, easy to carry, fast induction, etc., and can be widely applied in outdoor teaching and field investigation.

  18. Global microbialization of coral reefs.

    Science.gov (United States)

    Haas, Andreas F; Fairoz, Mohamed F M; Kelly, Linda W; Nelson, Craig E; Dinsdale, Elizabeth A; Edwards, Robert A; Giles, Steve; Hatay, Mark; Hisakawa, Nao; Knowles, Ben; Lim, Yan Wei; Maughan, Heather; Pantos, Olga; Roach, Ty N F; Sanchez, Savannah E; Silveira, Cynthia B; Sandin, Stuart; Smith, Jennifer E; Rohwer, Forest

    2016-04-25

    Microbialization refers to the observed shift in ecosystem trophic structure towards higher microbial biomass and energy use. On coral reefs, the proximal causes of microbialization are overfishing and eutrophication, both of which facilitate enhanced growth of fleshy algae, conferring a competitive advantage over calcifying corals and coralline algae. The proposed mechanism for this competitive advantage is the DDAM positive feedback loop (dissolved organic carbon (DOC), disease, algae, microorganism), where DOC released by ungrazed fleshy algae supports copiotrophic, potentially pathogenic bacterial communities, ultimately harming corals and maintaining algal competitive dominance. Using an unprecedented data set of >400 samples from 60 coral reef sites, we show that the central DDAM predictions are consistent across three ocean basins. Reef algal cover is positively correlated with lower concentrations of DOC and higher microbial abundances. On turf and fleshy macroalgal-rich reefs, higher relative abundances of copiotrophic microbial taxa were identified. These microbial communities shift their metabolic potential for carbohydrate degradation from the more energy efficient Embden-Meyerhof-Parnas pathway on coral-dominated reefs to the less efficient Entner-Doudoroff and pentose phosphate pathways on algal-dominated reefs. This 'yield-to-power' switch by microorganism directly threatens reefs via increased hypoxia and greater CO2 release from the microbial respiration of DOC.

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

    Science.gov (United States)

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

    2017-07-01

    Accurate estimation of terrestrial gross primary productivity (GPP) remains a challenge despite its importance in the global carbon cycle. Chlorophyll fluorescence (ChlF) has been recently adopted to understand photosynthesis and its response to the environment, particularly with remote sensing data. However, it remains unclear how ChlF and photosynthesis are linked at different spatial scales across the growing season. We examined seasonal relationships between ChlF and photosynthesis at the leaf, canopy, and ecosystem scales and explored how leaf-level ChlF was linked with canopy-scale solar-induced chlorophyll fluorescence (SIF) in a temperate deciduous forest at Harvard Forest, Massachusetts, USA. Our results show that ChlF captured the seasonal variations of photosynthesis with significant linear relationships between ChlF and photosynthesis across the growing season over different spatial scales (R 2  = 0.73, 0.77, and 0.86 at leaf, canopy, and satellite scales, respectively; P chlorophyll content (R 2  = 0.65 for canopy GPP SIF and chlorophyll content; P < 0.0001), leaf area index (LAI) (R 2  = 0.35 for canopy GPP SIF and LAI; P < 0.0001), and normalized difference vegetation index (NDVI) (R 2  = 0.36 for canopy GPP SIF and NDVI; P < 0.0001). Our results suggest that ChlF can be a powerful tool to track photosynthetic rates at leaf, canopy, and ecosystem scales. © 2016 John Wiley & Sons Ltd.

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

    Science.gov (United States)

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

    2009-09-01

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

  1. Effect of water deficit stress on proline contents, soluble sugars ...

    African Journals Online (AJOL)

    Effect of water deficit stress on proline contents, soluble sugars, chlorophyll and grain yield of sunflower ... Journal Home > Vol 11, No 1 (2012) > ... The objective of the present work was to determine the mechanisms of tolerance of four ...

  2. Petroleum hydrocarbon toxicity to corals: A review.

    Science.gov (United States)

    Turner, Nicholas R; Renegar, D Abigail

    2017-06-30

    The proximity of coral reefs to coastal urban areas and shipping lanes predisposes corals to petroleum pollution from multiple sources. Previous research has evaluated petroleum toxicity to coral using a variety of methodology, including monitoring effects of acute and chronic spills, in situ exposures, and ex situ exposures with both adult and larval stage corals. Variability in toxicant, bioassay conditions, species and other methodological disparities between studies prevents comprehensive conclusions regarding the toxicity of hydrocarbons to corals. Following standardized protocols and quantifying the concentration and composition of toxicant will aid in comparison of results between studies and extrapolation to actual spills. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Oceanic forcing of coral reefs.

    Science.gov (United States)

    Lowe, Ryan J; Falter, James L

    2015-01-01

    Although the oceans play a fundamental role in shaping the distribution and function of coral reefs worldwide, a modern understanding of the complex interactions between ocean and reef processes is still only emerging. These dynamics are especially challenging owing to both the broad range of spatial scales (less than a meter to hundreds of kilometers) and the complex physical and biological feedbacks involved. Here, we review recent advances in our understanding of these processes, ranging from the small-scale mechanics of flow around coral communities and their influence on nutrient exchange to larger, reef-scale patterns of wave- and tide-driven circulation and their effects on reef water quality and perceived rates of metabolism. We also examine regional-scale drivers of reefs such as coastal upwelling, internal waves, and extreme disturbances such as cyclones. Our goal is to show how a wide range of ocean-driven processes ultimately shape the growth and metabolism of coral reefs.

  4. The AtCAO gene, encoding chlorophyll a oxygenase, is required for chlorophyll b synthesis in Arabidopsis thaliana

    Science.gov (United States)

    Espineda, Cromwell E.; Linford, Alicia S.; Devine, Domenica; Brusslan, Judy A.

    1999-01-01

    Chlorophyll b is synthesized from chlorophyll a and is found in the light-harvesting complexes of prochlorophytes, green algae, and both nonvascular and vascular plants. We have used conserved motifs from the chlorophyll a oxygenase (CAO) gene from Chlamydomonas reinhardtii to isolate a homologue from Arabidopsis thaliana. This gene, AtCAO, is mutated in both leaky and null chlorina1 alleles, and DNA sequence changes cosegregate with the mutant phenotype. AtCAO mRNA levels are higher in three different mutants that have reduced levels of chlorophyll b, suggesting that plants that do not have sufficient chlorophyll b up-regulate AtCAO gene expression. Additionally, AtCAO mRNA levels decrease in plants that are grown under dim-light conditions. We have also found that the six major Lhcb proteins do not accumulate in the null ch1-3 allele. PMID:10468639

  5. CORAL Server and CORAL Server Proxy: Scalable Access to Relational Databases from CORAL Applications

    CERN Document Server

    Valassi, A; Kalkhof, A; Salnikov, A; Wache, M

    2011-01-01

    The CORAL software is widely used at CERN for accessing the data stored by the LHC experiments using relational database technologies. CORAL provides a C++ abstraction layer that supports data persistency for several backends and deployment models, including local access to SQLite files, direct client access to Oracle and MySQL servers, and read-only access to Oracle through the FroNTier web server and cache. Two new components have recently been added to CORAL to implement a model involving a middle tier "CORAL server" deployed close to the database and a tree of "CORAL server proxy" instances, with data caching and multiplexing functionalities, deployed close to the client. The new components are meant to provide advantages for read-only and read-write data access, in both offline and online use cases, in the areas of scalability and performance (multiplexing for several incoming connections, optional data caching) and security (authentication via proxy certificates). A first implementation of the two new c...

  6. Microbial Regulation in Gorgonian Corals

    Directory of Open Access Journals (Sweden)

    Laura D. Mydlarz

    2012-06-01

    Full Text Available Gorgonian corals possess many novel natural products that could potentially mediate coral-bacterial interactions. Since many bacteria use quorum sensing (QS signals to facilitate colonization of host organisms, regulation of prokaryotic cell-to-cell communication may represent an important bacterial control mechanism. In the present study, we examined extracts of twelve species of Caribbean gorgonian corals, for mechanisms that regulate microbial colonization, such as antibacterial activity and QS regulatory activity. Ethanol extracts of gorgonians collected from Puerto Rico and the Florida Keys showed a range of both antibacterial and QS activities using a specific Pseudomonas aeruginosa QS reporter, sensitive to long chain AHLs and a short chain N-acylhomoserine lactones (AHL biosensor, Chromobacterium violaceium. Overall, the gorgonian corals had higher antimicrobial activity against non-marine strains when compared to marine strains. Pseudopterogorgia americana, Pseusopterogorgia acerosa, and Pseudoplexuara flexuosa had the highest QS inhibitory effect. Interestingly, Pseudoplexuara porosa extracts stimulated QS activity with a striking 17-fold increase in signal. The stimulation of QS by P. porosa or other elements of the holobiont may encourage colonization or recruitment of specific microbial species. Overall, these results suggest the presence of novel stimulatory QS, inhibitory QS and bactericidal compounds in gorgonian corals. A better understanding of these compounds may reveal insight into coral-microbial ecology and whether a therapeutic potential exists.

  7. Coral reefs in the Anthropocene.

    Science.gov (United States)

    Hughes, Terry P; Barnes, Michele L; Bellwood, David R; Cinner, Joshua E; Cumming, Graeme S; Jackson, Jeremy B C; Kleypas, Joanie; van de Leemput, Ingrid A; Lough, Janice M; Morrison, Tiffany H; Palumbi, Stephen R; van Nes, Egbert H; Scheffer, Marten

    2017-05-31

    Coral reefs support immense biodiversity and provide important ecosystem services to many millions of people. Yet reefs are degrading rapidly in response to numerous anthropogenic drivers. In the coming centuries, reefs will run the gauntlet of climate change, and rising temperatures will transform them into new configurations, unlike anything observed previously by humans. Returning reefs to past configurations is no longer an option. Instead, the global challenge is to steer reefs through the Anthropocene era in a way that maintains their biological functions. Successful navigation of this transition will require radical changes in the science, management and governance of coral reefs.

  8. Long term photoacclimation responses of the coral Stylophora pistillata to reciprocal deep to shallow transplantation: photosynthesis and calcification

    Directory of Open Access Journals (Sweden)

    Itay eCohen

    2015-06-01

    Full Text Available Reciprocal transplantation of Stylophora pistillata coral fragments between deep (30m and shallow sites (3m was conducted gradually and resulted with 100% survival. Photoacclimation of transplants at both depths showed two distinct phases: at the first phase, within two weeks, zooxanthellae density decreased below (at 3m and increased beyond (at 30m these of the control values at the new depth, while chlorophyll a per zooxanthellae cell remained as in the original depths, thereby fully adjusting areal chlorophyll concentration. On the second phase, after six months, zooxanthellae chlorophyll and their quantum yield (Fv/Fm were adjusted at both new depths. Such regulated acclimation was also observed in the maximal photosynthesis rate of both transplants, whereas respiration adjustment was rapid. These results differ from previously reported rapid shade and light acclimation strategies hence we suggest that acclimation mechanism changes when certain symbiont type is exposed to depth out of its boundary zone. Despite seemingly having become physiologically acclimated, calcification at both new depths was only half the rate achieved by the controls, suggesting that the coral host requires even longer time than the symbionts to acclimate.

  9. Advancing the integration of spatial data to map human and natural drivers on coral reefs

    Science.gov (United States)

    Gove, Jamison M.; Walecka, Hilary R.; Donovan, Mary K.; Williams, Gareth J.; Jouffray, Jean-Baptiste; Crowder, Larry B.; Erickson, Ashley; Falinski, Kim; Friedlander, Alan M.; Kappel, Carrie V.; Kittinger, John N.; McCoy, Kaylyn; Norström, Albert; Nyström, Magnus; Oleson, Kirsten L. L.; Stamoulis, Kostantinos A.; White, Crow; Selkoe, Kimberly A.

    2018-01-01

    A major challenge for coral reef conservation and management is understanding how a wide range of interacting human and natural drivers cumulatively impact and shape these ecosystems. Despite the importance of understanding these interactions, a methodological framework to synthesize spatially explicit data of such drivers is lacking. To fill this gap, we established a transferable data synthesis methodology to integrate spatial data on environmental and anthropogenic drivers of coral reefs, and applied this methodology to a case study location–the Main Hawaiian Islands (MHI). Environmental drivers were derived from time series (2002–2013) of climatological ranges and anomalies of remotely sensed sea surface temperature, chlorophyll-a, irradiance, and wave power. Anthropogenic drivers were characterized using empirically derived and modeled datasets of spatial fisheries catch, sedimentation, nutrient input, new development, habitat modification, and invasive species. Within our case study system, resulting driver maps showed high spatial heterogeneity across the MHI, with anthropogenic drivers generally greatest and most widespread on O‘ahu, where 70% of the state’s population resides, while sedimentation and nutrients were dominant in less populated islands. Together, the spatial integration of environmental and anthropogenic driver data described here provides a first-ever synthetic approach to visualize how the drivers of coral reef state vary in space and demonstrates a methodological framework for implementation of this approach in other regions of the world. By quantifying and synthesizing spatial drivers of change on coral reefs, we provide an avenue for further research to understand how drivers determine reef diversity and resilience, which can ultimately inform policies to protect coral reefs. PMID:29494613

  10. Leaf and canopy photosynthesis of a chlorophyll deficient soybean mutant.

    Science.gov (United States)

    Sakowska, Karolina; Alberti, Giorgio; Genesio, Lorenzo; Peressotti, Alessandro; Delle Vedove, Gemini; Gianelle, Damiano; Colombo, Roberto; Rodeghiero, Mirco; Panigada, Cinzia; Juszczak, Radosław; Celesti, Marco; Rossini, Micol; Haworth, Matthew; Campbell, Benjamin W; Mevy, Jean-Philippe; Vescovo, Loris; Cendrero-Mateo, M Pilar; Rascher, Uwe; Miglietta, Franco

    2018-03-02

    The photosynthetic, optical, and morphological characteristics of a chlorophyll-deficient (Chl-deficient) "yellow" soybean mutant (MinnGold) were examined in comparison with 2 green varieties (MN0095 and Eiko). Despite the large difference in Chl content, similar leaf photosynthesis rates were maintained in the Chl-deficient mutant by offsetting the reduced absorption of red photons by a small increase in photochemical efficiency and lower non-photochemical quenching. When grown in the field, at full canopy cover, the mutants reflected a significantly larger proportion of incoming shortwave radiation, but the total canopy light absorption was only slightly reduced, most likely due to a deeper penetration of light into the canopy space. As a consequence, canopy-scale gross primary production and ecosystem respiration were comparable between the Chl-deficient mutant and the green variety. However, total biomass production was lower in the mutant, which indicates that processes other than steady state photosynthesis caused a reduction in biomass accumulation over time. Analysis of non-photochemical quenching relaxation and gas exchange in Chl-deficient and green leaves after transitions from high to low light conditions suggested that dynamic photosynthesis might be responsible for the reduced biomass production in the Chl-deficient mutant under field conditions. © 2018 John Wiley & Sons Ltd.

  11. Change in algal symbiont communities after bleaching, not prior heat exposure, increases heat tolerance of reef corals.

    Science.gov (United States)

    Silverstein, Rachel N; Cunning, Ross; Baker, Andrew C

    2015-01-01

    Mutualistic organisms can be particularly susceptible to climate change stress, as their survivorship is often limited by the most vulnerable partner. However, symbiotic plasticity can also help organisms in changing environments by expanding their realized niche space. Coral-algal (Symbiodinium spp.) symbiosis exemplifies this dichotomy: the partnership is highly susceptible to 'bleaching' (stress-induced symbiosis breakdown), but stress-tolerant symbionts can also sometimes mitigate bleaching. Here, we investigate the role of diverse and mutable symbiotic partnerships in increasing corals' ability to thrive in high temperature conditions. We conducted repeat bleaching and recovery experiments on the coral Montastraea cavernosa, and used quantitative PCR and chlorophyll fluorometry to assess the structure and function of Symbiodinium communities within coral hosts. During an initial heat exposure (32 °C for 10 days), corals hosting only stress-sensitive symbionts (Symbiodinium C3) bleached, but recovered (at either 24 °C or 29 °C) with predominantly (>90%) stress-tolerant symbionts (Symbiodinium D1a), which were not detected before bleaching (either due to absence or extreme low abundance). When a second heat stress (also 32 °C for 10 days) was applied 3 months later, corals that previously bleached and were now dominated by D1a Symbiodinium experienced less photodamage and symbiont loss compared to control corals that had not been previously bleached, and were therefore still dominated by Symbiodinium C3. Additional corals that were initially bleached without heat by a herbicide (DCMU, at 24 °C) also recovered predominantly with D1a symbionts, and similarly lost fewer symbionts during subsequent thermal stress. Increased thermotolerance was also not observed in C3-dominated corals that were acclimated for 3 months to warmer temperatures (29 °C) before heat stress. These findings indicate that increased thermotolerance post-bleaching resulted from

  12. CORAL Server and CORAL Server Proxy: Scalable Access to Relational Databases from CORAL Applications

    International Nuclear Information System (INIS)

    Valassi, A; Kalkhof, A; Bartoldus, R; Salnikov, A; Wache, M

    2011-01-01

    The CORAL software is widely used at CERN by the LHC experiments to access the data they store on relational databases, such as Oracle. Two new components have recently been added to implement a model involving a middle tier 'CORAL server' deployed close to the database and a tree of 'CORAL server proxies', providing data caching and multiplexing, deployed close to the client. A first implementation of the two new components, released in the summer 2009, is now deployed in the ATLAS online system to read the data needed by the High Level Trigger, allowing the configuration of a farm of several thousand processes. This paper reviews the architecture of the software, its development status and its usage in ATLAS.

  13. Regional ocean-colour chlorophyll algorithms for the Red Sea

    KAUST Repository

    Brewin, Robert J.W.

    2015-05-18

    The Red Sea is a semi-enclosed tropical marine ecosystem that stretches from the Gulf of Suez and Gulf of Aqaba in the north, to the Gulf of Aden in the south. Despite its ecological and economic importance, its biological environment is relatively unexplored. Satellite ocean-colour estimates of chlorophyll concentration (an index of phytoplankton biomass) offer an observational platform to monitor the health of the Red Sea. However, little is known about the optical properties of the region. In this paper, we investigate the optical properties of the Red Sea in the context of satellite ocean-colour estimates of chlorophyll concentration. Making use of a new merged ocean-colour product, from the European Space Agency (ESA) Climate Change Initiative, and in situ data in the region, we test the performance of a series of ocean-colour chlorophyll algorithms. We find that standard algorithms systematically overestimate chlorophyll when compared with the in situ data. To investigate this bias we develop an ocean-colour model for the Red Sea, parameterised to data collected during the Tara Oceans expedition, that estimates remote-sensing reflectance as a function of chlorophyll concentration. We used the Red Sea model to tune the standard chlorophyll algorithms and the overestimation in chlorophyll originally observed was corrected. Results suggest that the overestimation was likely due to an excess of CDOM absorption per unit chlorophyll in the Red Sea when compared with average global conditions. However, we recognise that additional information is required to test the influence of other potential sources of the overestimation, such as aeolian dust, and we discuss uncertainties in the datasets used. We present a series of regional chlorophyll algorithms for the Red Sea, designed for a suite of ocean-colour sensors, that may be used for further testing.

  14. Chlorophyll derivatives for pest and disease control: Are they safe?

    International Nuclear Information System (INIS)

    Azizullah, Azizullah; Murad, Waheed

    2015-01-01

    Chlorophyll derivatives are getting widespread acceptance among the researchers as natural photosensitizers for photodynamic control of pests and disease vectors; however, rare attention has been given to evaluation of their toxicity to non-target organisms in the environment. This perspective article highlights that chlorophyll derivatives may not be as safe as believed and can possibly pose risk to non-target organisms in the environment. We invite the attention of environmental biologists, particularly ecotoxicologists, to contribute their role in making the application of chlorophyll derivatives more environmentally friendly and publicly acceptable

  15. Gamma ray induced chlorophyll and morphological mutants in grasspea

    International Nuclear Information System (INIS)

    Das, P.K.; Kundagrami, S.

    2000-01-01

    Higher dose of gamma ray treatment such as 30 kR promoted larger chlorophyll as well as morphological mutation frequency and spectrum. In both M 1 and M 2 generation marginata significantly out numbered other types of chlorophyll mutations. On the other hand, along morphological mutations stunted growth types were recovered more frequently. Both the genotypes Nirmal and P-24 differed greatly for their mutagenic specificity. In both M 1 and M 2 generation Nirmal recorded higher chlorophyll and morphological mutation frequency and spectrum indicating differential genotype response to different dosages of gamma ray treatment. (author)

  16. Chlorophyll derivatives for pest and disease control: Are they safe?

    Energy Technology Data Exchange (ETDEWEB)

    Azizullah, Azizullah, E-mail: azizswabi@gmail.com; Murad, Waheed

    2015-01-15

    Chlorophyll derivatives are getting widespread acceptance among the researchers as natural photosensitizers for photodynamic control of pests and disease vectors; however, rare attention has been given to evaluation of their toxicity to non-target organisms in the environment. This perspective article highlights that chlorophyll derivatives may not be as safe as believed and can possibly pose risk to non-target organisms in the environment. We invite the attention of environmental biologists, particularly ecotoxicologists, to contribute their role in making the application of chlorophyll derivatives more environmentally friendly and publicly acceptable.

  17. Stable Carbon Isotopes (δ 13C) in Coral Skeletons: Experimental Approach and Applications for Paleoceanography

    Science.gov (United States)

    Grottoli, A. G.

    2004-12-01

    Scleractinian corals obtain fixed carbon via photosynthesis by their endosymbiotic algae (zooxanthellae) and via hetertrophy (injestion of zooplankton, δ 13C ≈ -17 to -22‰ ). Carbon dioxide (CO2) used for photosynthesis is obtained from seawater (δ 13C ≈ 0%) or from respired CO2 within the coral host. The δ 13C of the carbon used in the formation of the underlying coral skeleton is fractionated as a result of both of these metabolic processes. Here I have pooled evidence from several field and tank experiments on the effect of photosynthesis and heterotrophy of coral skeletal δ 13C. In the experiments, decreases in light levels due to shading or depth resulted in a significant decrease in skeletal δ 13C in all species studied (Pavona gigantea, Pavona clavus, Porites compressa). Decreases in photosynthesis in bleached corals also resulted in a decrease in skeletal δ 13C compared to non-bleached corals growing under the same conditions and at the same location. Skeletal δ 13C also decreased at higher than normal light levels most likely due to photoinhibition. Thus, decreases in photosynthesis due to reduced light levels, due to bleaching-induced decreases in chlorophyll a concentrations, or due to photodamage-induced decreases in functional cholorphyll a, results in significant δ 13C decreases. Comprehensive interpretation of all of the data showed that changes in photosynthesis itself can drive the changes in δ 13C. In field experiments, the addition of natural concentrations of zooplankton to the diet resulted in decreases in skeletal δ 13C. Such a decrease was more pronounced with depth and in P. gigantea compared to P. clavus. In situ feeding experiments have since confirmed these findings. However under tank conditions with unaturally high feeding rates, enhanced nitrogen supply in the diet can disrupt the coral-algal symbiosis, stimlate zooxanthellae growth and photosynthesis, and cause an incrase in skeletal δ 13C. It is proposed that under

  18. Prooxidative and antioxidative properties of β-carotene in chlorophyll and riboflavin photosensitized oil-in-water emulsions.

    Science.gov (United States)

    Park, JungWoo; Kim, Tae Soo; Kim, Mi-Ja; Lee, JaeHwan

    2013-09-01

    Effects of β-carotene on the oxidative stability of chlorophyll or riboflavin photosensitized oil-in-water (O/W) emulsions were determined by analysing the depleted headspace oxygen content, lipid hydroperoxides, fluorescence intensity, and headspace volatiles. As the concentration of β-carotene increased from 0 to 10, 100, and 1000 μM, the oxidative stability of samples containing chlorophylls decreased in a concentration-dependent manner under light, indicating that β-carotene acted as a prooxidant. However, in riboflavin photosensitized O/W emulsions, 100 and 1000 μM β-carotene inhibited lipid oxidation. Although β-carotene protected both photosensitisers in O/W emulsions, β-carotene displayed antioxidative or prooxidative properties, which depended on the polarity of the photosensitisers. The development of t-2-heptenal and 1-octen-3-ol increased greatly in chlorophyll sensitised O/W emulsions with an increase in β-carotene concentration, implying that more singlet oxygen oxidation occurred due to the higher levels of remaining chlorophylls. However, the content of t-2-heptenal and 1-octen-3-ol in the riboflavin sensitised O/W emulsions was not significantly correlated with the β-carotene concentration, which indicates that β-carotene in the lipid particles effectively quenched singlet oxygen. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. The cumulative impact of annual coral bleaching can turn some coral species winners into losers.

    Science.gov (United States)

    Grottoli, Andréa G; Warner, Mark E; Levas, Stephen J; Aschaffenburg, Matthew D; Schoepf, Verena; McGinley, Michael; Baumann, Justin; Matsui, Yohei

    2014-12-01

    Mass coral bleaching events caused by elevated seawater temperatures result in extensive coral loss throughout the tropics, and are projected to increase in frequency and severity. If bleaching becomes an annual event later in this century, more than 90% of coral reefs worldwide may be at risk of long-term degradation. While corals can recover from single isolated bleaching and can acclimate to recurring bleaching events that are separated by multiple years, it is currently unknown if and how they will survive and possibly acclimatize to annual coral bleaching. Here, we demonstrate for the first time that annual coral bleaching can dramatically alter thermal tolerance in Caribbean corals. We found that high coral energy reserves and changes in the dominant algal endosymbiont type (Symbiodinium spp.) facilitated rapid acclimation in Porites divaricata, whereas low energy reserves and a lack of algal phenotypic plasticity significantly increased susceptibility in Porites astreoides to bleaching the following year. Phenotypic plasticity in the dominant endosymbiont type of Orbicella faveolata did not prevent repeat bleaching, but may have facilitated rapid recovery. Thus, coral holobiont response to an isolated single bleaching event is not an accurate predictor of its response to bleaching the following year. Rather, the cumulative impact of annual coral bleaching can turn some coral species 'winners' into 'losers', and can also facilitate acclimation and turn some coral species 'losers' into 'winners'. Overall, these findings indicate that cumulative impact of annual coral bleaching could result in some species becoming increasingly susceptible to bleaching and face a long-term decline, while phenotypically plastic coral species will acclimatize and persist. Thus, annual coral bleaching and recovery could contribute to the selective loss of coral diversity as well as the overall decline of coral reefs in the Caribbean. © 2014 John Wiley & Sons Ltd.

  20. Photogeneration of charges in microcrystalline chlorophyll a

    International Nuclear Information System (INIS)

    Kassi, Hassan; Barazzouk, Said; Brullemans, Marc; Leblanc, Roger M.; Hotchandani, Surat

    2010-01-01

    The electric-field and temperature dependence of hole photogeneration in chlorophyll a (Chla) have been analyzed in terms of electric-field assisted thermal dissociation of charge pairs based on Onsager theory. An excellent agreement between the experimental and theoretical values of the slope-to-intercept ratio, S/I, for the plot of photogeneration efficiency vs. electric field at low field strengths provides a proof for the applicability of the Onsager approach to the photogeneration of charges in Chla. A value of 19 nm has been obtained for Coulomb capture radius, r c , from S/I. From the temperature dependence of photogeneration, the initial separation, r 0 , of photogenerated electron-hole has been evaluated, and has a value of 1.24 nm. This smaller r 0 compared to r c leads to a feeble dissociation probability of electron-hole pairs into free carriers, and may, among other factors, explain the low power conversion efficiencies of Chla photovoltaic cells.

  1. Photogeneration of charges in microcrystalline chlorophyll a

    Energy Technology Data Exchange (ETDEWEB)

    Kassi, Hassan [Scientech R and D, Inc., 2200 Rue Didbec S., Bureau 203, Trois-Rivieres, Trois-Rivieres, QC, G8Z 4H1 (Canada); Barazzouk, Said, E-mail: barazzos@uqtr.c [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada); Brullemans, Marc [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada); Leblanc, Roger M. [Department of Chemistry, University of Miami, P.O. Box 249118, Coral Gables, FL 33124-0431 (United States); Hotchandani, Surat [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada)

    2010-07-01

    The electric-field and temperature dependence of hole photogeneration in chlorophyll a (Chla) have been analyzed in terms of electric-field assisted thermal dissociation of charge pairs based on Onsager theory. An excellent agreement between the experimental and theoretical values of the slope-to-intercept ratio, S/I, for the plot of photogeneration efficiency vs. electric field at low field strengths provides a proof for the applicability of the Onsager approach to the photogeneration of charges in Chla. A value of 19 nm has been obtained for Coulomb capture radius, r{sub c}, from S/I. From the temperature dependence of photogeneration, the initial separation, r{sub 0}, of photogenerated electron-hole has been evaluated, and has a value of 1.24 nm. This smaller r{sub 0} compared to r{sub c} leads to a feeble dissociation probability of electron-hole pairs into free carriers, and may, among other factors, explain the low power conversion efficiencies of Chla photovoltaic cells.

  2. Quantifying Coral Reef Ecosystem Services

    Science.gov (United States)

    Coral reefs have been declining during the last four decades as a result of both local and global anthropogenic stresses. Numerous research efforts to elucidate the nature, causes, magnitude, and potential remedies for the decline have led to the widely held belief that the recov...

  3. Primary Life Stage Boron Isotope and Trace Elements Incorporation in Aposymbiotic Acropora millepora Coral under Ocean Acidification and Warming

    Directory of Open Access Journals (Sweden)

    Henry C. Wu

    2017-05-01

    Full Text Available Early-life stages of reef-building corals are vital to coral existence and reef maintenance. It is therefore crucial to study juvenile coral response to future climate change pressures. Moreover, corals are known to be reliable recorders of environmental conditions in their skeletal materials. Aposymbiotic Acropora millepora larvae were cultured in different seawater temperature (27 and 29°C and pCO2 (390 and 750 μatm conditions to understand the impacts of “end of century” ocean acidification (OA and ocean warming (OW conditions on skeletal morphology and geochemistry. The experimental conditions impacted primary polyp juvenile coral skeletal morphology and growth resulting in asymmetric translucent appearances with brittle skeleton features. The impact of OA resulted in microstructure differences with decreased precipitation or lengthening of fasciculi and disorganized aragonite crystals that led to more concentrations of centers of calcifications. The coral skeletal δ11B composition measured by laser ablation MC-ICP-MS was significantly affected by pCO2 (p = 0.0024 and water temperature (p = 1.46 × 10−5. Reconstructed pH of the primary polyp skeleton using the δ11B proxy suggests a difference in coral calcification site and seawater pH consistent with previously observed coral pH up-regulation. Similarly, trace element results measured by laser ablation ICP-MS indicate the impact of pCO2. Primary polyp juvenile Sr/Ca ratio indicates a bias in reconstructed sea surface temperature (SST under higher pCO2 conditions. Coral microstructure content changes (center of calcification and fasciculi due to OA possibly contributed to the variability in B/Ca ratios. Our results imply that increasing OA and OW may lead to coral acclimation issues and species-specific inaccuracies of the commonly used Sr/Ca-SST proxy.

  4. Sharing the slope: depth partitioning of agariciid corals and associated

    NARCIS (Netherlands)

    Bongaerts, P.; Frade, P.R.; Ogier, J.J.; Hay, K.B.; van Bleijswijk, J.; Englebert, N.; Vermeij, M.J.A.; Bak, R.P.M.; Visser, P.M.; Hoegh-Guldberg, O.

    2013-01-01

    Background: Scleractinian