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  1. Lodging Update: Providence, Rhode Island

    Directory of Open Access Journals (Sweden)

    Ragel Roginsky

    2013-04-01

    Full Text Available Each quarter, Pinnacle Advisory Group prepares an analysis of the New England lodging industry, which provides a regional summary and then focuses in depth on a particular market. These reviews look at recent and proposed supply changes, factors affecting demand and growth rates, and the effects of interactions between such supply and demand trends. In this issue, the authors spotlight the lodging market in Providence, Rhode Island.

  2. Rhode Island Hurricane Evacuation Study Technical Data Report

    National Research Council Canada - National Science Library

    1995-01-01

    .... The purpose of the study is to provide the Rhode Island Emergency Management Agency and Rhode Island coastal communities with realistic data quantifying the major factors involved in hurricane...

  3. Rhode Island unemployment

    OpenAIRE

    Leonard Lardaro

    2010-01-01

    How can a state like Rhode Island have such a high unemployment rate? This question has been asked often over the past year, especially since at one point, Rhode Island found itself with the dubious distinction of having the highest unemployment rate in the United States. Following that extreme, Rhode Island seemed to settle into a niche where its rank was third nationally.

  4. Meeting changing conditoins at the Rhode Island Medical Center cogeneration plant

    International Nuclear Information System (INIS)

    Galamaga, D.P.; Bowen, P.T.

    1993-01-01

    The Rhode Island Department of Mental Health, Retardation and Hospitals is one state department in Rhode Island whose basic function is to provide services to seriously disabled individuals throughout the state. Savings in operating expenses from the Rhode Island Medical Center Central Power Plant have accruded to provide operating funds for the major programs. Operating under a Director who reports to the Governor of Rhode Island, the Department has three major divisions, approximately 2500 employees, and a budget of 200 million dollars. Its operations extend throughout the state and the major focus for hospital or institutional levels of care reside in three major locations, the Dr. U.E. Zambarano Memorial Hospital in northern Rhode Island, the Dr. Joseph Ladd Center in southern Rhode Island, and the Rhode Island Medical Center in the middle of the state. Besides these institution-based operations, the Department sponsors a wide range of rehabilitative programming in the community other through direct operations of facilities such as group homes or through contracts with private non-profit providers of service

  5. Willingness of Rhode Island Dentists to Provide Limited Preventive Primary Care.

    Science.gov (United States)

    Dang, Catherine Tuyet Mai; Shield, Renee R; Giddon, Donald B

    2016-07-01

    In response to the shortage of primary care physicians and the need for greater intercollaboration among health professionals, dentists with sufficient medical and surgical training are an untapped resource to provide limited preventive primary care (LPPC), such as chairside screening for chronic diseases. The objective of this study was to determine attitudes of Rhode Island dentists toward becoming more involved in the overall health of their patients. Using a 5-point scale (1 being highest), a pretested survey was administered to 92 respondent RI dentists who were asked to indicate their willingness to become more involved in patients' overall health, and undergo additional training to provide LPPC. Their moderate level of willingness was offset by great concern for liability, with older dentists being significantly more willing to assume these additional responsibilities than younger dentists (pstomiatrist was still dentist first, but with no significant difference between the mean ranks of dentist and oral physician.[Full article available at http://rimed.org/rimedicaljournal-2016-07.asp, free with no login].

  6. More Rhode Island Adults Have Dental Coverage After the Medicaid Expansion: Did More Adults Receive Dental Services? Did More Dentists Provide Services?

    Science.gov (United States)

    Zwetchkenbaum, Samuel; Oh, Junhie

    2017-10-02

    Under the Affordable Care Act (ACA) Medicaid expansion since 2014, 68,000 more adults under age 65 years were enrolled in Rhode Island Medicaid as of December 2015, a 78% increase from 2013 enrollment. This report assesses changes in dental utilization associated with this expansion. Medicaid enrollment and dental claims for calendar years 2012-2015 were extracted from the RI Medicaid Management Information System. Among adults aged 18-64 years, annual numbers and percentages of Medicaid enrollees who received any dental service were summarized. Additionally, dental service claims were assessed by provider type (private practice or health center). Although 15,000 more adults utilized dental services by the end of 2015, the annual percentage of Medicaid enrollees who received any dental services decreased over the reporting periods, compared to pre-ACA years (2012-13: 39%, 2014: 35%, 2015: 32%). From 2012 to 2015, dental patient increases in community health centers were larger than in private dental offices (78% vs. 34%). Contrary to the Medicaid population increase, the number of dentists that submitted Medicaid claims decreased, particularly among dentists in private dental offices; the percentage of RI private dentists who provided any dental service to adult Medicaid enrollees decreased from 29% in 2012 to 21% in 2015. Implementation of Medicaid expansion has played a critical role in increasing the number of Rhode Islanders with dental coverage, particularly among low-income adults under age 65. However, policymakers must address the persistent and worsening shortage of dental providers that accept Medicaid to provide a more accessible source of oral healthcare for all Rhode Islanders. [Full article available at http://rimed.org/rimedicaljournal-2017-10.asp].

  7. RI State Profile. Rhode Island: New England Common Assessments Program (NCAP)

    Science.gov (United States)

    Center on Education Policy, 2010

    2010-01-01

    This paper provides information about Rhode Island's New England Common Assessments Program (NCAP), a comprehensive test. Its purpose is to measure each student's overall proficiency for graduation in the six core academic areas. In 2008, the Board of Regents in Rhode Island established new regulations for high school diplomas. Beginning with the…

  8. Updating Rhode Island's strategic highway safety plan (SHSP).

    Science.gov (United States)

    2012-05-01

    This report summarizes the peer exchange sponsored by the Rhode Island : Department of Transportation (RIDOT) that focused on Rhode Islands SHSP : update. : Rhode Islands goals for the peer exchange included learning from other States : expe...

  9. Alternative Fuels Data Center: Rhode Island Transportation Data for

    Science.gov (United States)

    stations in Rhode Island with alternative fuels Fuel Public Private Biodiesel (B20 and above) 3 3 More Rhode Island Videos on YouTube Video thumbnail for Cooking Oil Powers Biodiesel Vehicles in Rhode Island Cooking Oil Powers Biodiesel Vehicles in Rhode Island July 14, 2017 https://www.youtube.com/embed

  10. National Uranium Resource Evaluation: Providence Quadrangle, Connecticut, Rhode Island, and Massachusetts

    International Nuclear Information System (INIS)

    Zollinger, R.C.; Blauvelt, R.P.; Chew, R.T. III.

    1982-09-01

    The Providence Quadrangle, Connecticut, Rhode Island, and Massachusetts, was evaluated to a depth of 1500 m to identify environments and delineate areas favorable for uranium deposits. Criteria for this evaluation were developed by the National Uranium Resource Evaluation program. Environments were recognized after literature research, surface and subsurface geologic reconnaissance, and examination of known uranium occurrences and aeroradioactivity anomalies. Environments favorable for authigenic uranium deposits were found in the Quincy and Cowesett Granites. An environment favorable for contact-metasomatic deposits is in and around the borders of the Narragansett Pier Granite where it intrudes the Pennsylvanian sediments of the Narragansett Basin. An environment favorable for authigenic deposits in metamorphic rocks is in a migmatite on the eastern edge of the Scituate Granite Gneiss batholith. Environments favorable for contact-metasomatic deposits occur at the contacts between many of the granitic rocks and metamorphic rocks of the Blackstone Series. Results of this study also indicate environments favorable for sandstone-type uranium deposits are present in the rocks of the Narragansett Basin. Environments unfavorable for uranium deposits in the quadrangle include all granites not classified as favorable and the metamorphic rocks of eastern Connecticut. Glacial deposits and Cretaceous-Tertiary sediments remain unevaluated

  11. Cost-Effectiveness Analysis of the Residential Provisions of the 2015 IECC for Rhode Island

    Energy Technology Data Exchange (ETDEWEB)

    Mendon, Vrushali V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhao, Mingjie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Taylor, Zachary T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poehlman, Eric A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-02-15

    The 2015 IECC provides cost-effective savings for residential buildings in Rhode Island. Moving to the 2015 IECC from the 2012 IECC base code is cost-effective for residential buildings in all climate zones in Rhode Island.

  12. Rhode Island State Briefing Book on low-level radioactive-waste management

    Energy Technology Data Exchange (ETDEWEB)

    1981-07-01

    The Rhode Island State Briefing Book is one of a series of state briefing books on low-level radioactive waste management practices. It has been prepared to assist state and federal agency officials in planning for safe low-level radioactive waste disposal. The report contains a profile of low-level radioactive waste generators in Rhode Island. The profile is the result of a survey of radioactive material licensees in Rhode Island. The briefing book also contains a comprehensive assessment of low-level radioactive waste management issues and concerns as defined by all major interested parties including industry, government, the media, and interest groups. The assessment was developed through personal communications with representatives of interested parties, and through a review of media sources. Lastly, the briefing book provides demographic and socioeconomic data and a discussion of relevant government agencies and activities, all of which may affect waste management practices in Rhode Island.

  13. Rhode Island State Briefing Book on low-level radioactive-waste management

    International Nuclear Information System (INIS)

    1981-07-01

    The Rhode Island State Briefing Book is one of a series of state briefing books on low-level radioactive waste management practices. It has been prepared to assist state and federal agency officials in planning for safe low-level radioactive waste disposal. The report contains a profile of low-level radioactive waste generators in Rhode Island. The profile is the result of a survey of radioactive material licensees in Rhode Island. The briefing book also contains a comprehensive assessment of low-level radioactive waste management issues and concerns as defined by all major interested parties including industry, government, the media, and interest groups. The assessment was developed through personal communications with representatives of interested parties, and through a review of media sources. Lastly, the briefing book provides demographic and socioeconomic data and a discussion of relevant government agencies and activities, all of which may affect waste management practices in Rhode Island

  14. Rhodes University

    African Journals Online (AJOL)

    Samridhi Sharma

    2013-10-29

    Oct 29, 2013 ... been taken may improve the reception, by the target audience, of the intended communication. This may ... alcohol marketing. Similarly .... of the intended users (Rhodes University support staff ..... Digital Human Modeling and.

  15. 77 FR 43514 - Anchorage Regulations; Narragansett Bay and Rhode Island Sound, RI

    Science.gov (United States)

    2012-07-25

    ...-AA01 Anchorage Regulations; Narragansett Bay and Rhode Island Sound, RI AGENCY: Coast Guard, DHS... Narragansett Bay, Rhode Island, and adding an offshore anchorage in Rhode Island Sound south of Brenton Point... rulemaking (NPRM) entitled ``Anchorage Regulations; Narragansett Bay and Rhode Island Sound, RI,'' in the...

  16. Rhode Island crystalline repository project: Technical progress report, 1984-1986

    International Nuclear Information System (INIS)

    1986-01-01

    A Nuclear Waste Fund established by the Nuclear Waste Policy Act of 1982 provided financial support to the State of Rhode Island for its participation in the high-level radioactive waste repository siting program. In 1984, the Office of the Governor set up a multidisciplinary Project Review Team consisting of staff from three State agencies and the University of Rhode Island. Members of the Review Team attended several meetings throughout the reporting period to voice their concerns about siting directly to the US Department of Energy (DOE). Written comments were also submitted on draft plans and reports. Many of Rhode Island's recommendations in these comments were later adopted. In May, 1986, Secretary of Energy John Herrington announced the suspension of the crystalline repository siting program. The remainder of the year was spent monitoring litigation challenging that decision and pending legislation. Administrative phase-down of the program was essentially complete by the close of the calendar year

  17. Soil Survey Geographic (SSURGO) Soil Polygons for the State of Rhode Island: Bristol, Kent, Newport, Providence, and Washington Counties

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — 2013 VERSION 6 Spatial: This data set is a digital soil survey and generally is the most detailed level of soil geographic data developed by the National Cooperative...

  18. 76 FR 60850 - Rhode Island; Emergency and Related Determinations

    Science.gov (United States)

    2011-09-30

    ... Hurricane Irene beginning on August 26, 2011, and continuing, are of sufficient severity and magnitude to... State of Rhode Island have been designated as adversely affected by this declared emergency: Providence..., Disaster Unemployment Assistance (DUA); 97.046, Fire Management Assistance Grant; 97.048, Disaster Housing...

  19. Perceptions of electronic health record implementation: a statewide survey of physicians in Rhode Island.

    Science.gov (United States)

    Wylie, Matthew C; Baier, Rosa R; Gardner, Rebekah L

    2014-10-01

    Although electronic health record use improves healthcare delivery, adoption into clinical practice is incomplete. We sought to identify the extent of adoption in Rhode Island and the characteristics of physicians and electronic health records associated with positive experience. We performed a cross-sectional study of data collected by the Rhode Island Department of Health for the Health Information Technology Survey 2009 to 2013. Survey questions included provider and practice demographics, health record information, and Likert-type scaled questions regarding how electronic health record use affected clinical practice. The survey response rate ranged from 50% to 65%, with 62% in 2013. Increasing numbers of physicians in Rhode Island use an electronic health record. In 2013, 81% of physicians used one, and adoption varied by clinical subspecialty. Most providers think that electronic health record use improves billing and quality improvement but has not improved job satisfaction. Physicians with longer and more sophisticated electronic health record use report positive effects of introduction on all aspects of practice examined (P electronic health record introduction (P electronic health record vendors most frequently used in Rhode Island, 5 were associated with improved job satisfaction. We report the largest statewide study of electronic health record adoption to date. We found increasing physician use in Rhode Island, and the extent of adoption varies by subspecialty. Although older physicians are less likely to be positive about electronic health record adoption, longer and more sophisticated use are associated with more positive opinions, suggesting acceptance will grow over time. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Soil Survey Geographic (SSURGO) Special Point Features for the State of Rhode Island: Bristol, Kent, Newport, Providence, and Washington Counties

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This data set is a digital soil survey and generally is the most detailed level of soil geographic data developed by the National Cooperative Soil Survey. The...

  1. Soil Survey Geographic (SSURGO) Special Line Features for the State of Rhode Island: Bristol, Kent, Newport, Providence, and Washington County

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This data set is a digital soil survey and generally is the most detailed level of soil geographic data developed by the National Cooperative Soil Survey. The...

  2. 76 FR 15246 - Anchorage Regulations; Narragansett Bay and Rhode Island Sound, RI

    Science.gov (United States)

    2011-03-21

    ...-AA01 Anchorage Regulations; Narragansett Bay and Rhode Island Sound, RI AGENCY: Coast Guard, DHS... Rhode Island Sound south of Brenton Point, Rhode Island, for use by vessels waiting to enter... Sound that under current informal practice is routinely used by mariners as an anchorage while waiting...

  3. Rubisco catalytic properties of wild and domesticated relatives provide scope for improving wheat photosynthesis.

    Science.gov (United States)

    Prins, Anneke; Orr, Douglas J; Andralojc, P John; Reynolds, Matthew P; Carmo-Silva, Elizabete; Parry, Martin A J

    2016-03-01

    Rubisco is a major target for improving crop photosynthesis and yield, yet natural diversity in catalytic properties of this enzyme is poorly understood. Rubisco from 25 genotypes of the Triticeae tribe, including wild relatives of bread wheat (Triticum aestivum), were surveyed to identify superior enzymes for improving photosynthesis in this crop. In vitro Rubisco carboxylation velocity (V c), Michaelis-Menten constants for CO2 (K c) and O2 (K o) and specificity factor (S c/o) were measured at 25 and 35 °C. V c and K c correlated positively, while V c and S c/o were inversely related. Rubisco large subunit genes (rbcL) were sequenced, and predicted corresponding amino acid differences analysed in relation to the corresponding catalytic properties. The effect of replacing native wheat Rubisco with counterparts from closely related species was analysed by modelling the response of photosynthesis to varying CO2 concentrations. The model predicted that two Rubisco enzymes would increase photosynthetic performance at 25 °C while only one of these also increased photosynthesis at 35 °C. Thus, under otherwise identical conditions, catalytic variation in the Rubiscos analysed is predicted to improve photosynthetic rates at physiological CO2 concentrations. Naturally occurring Rubiscos with superior properties amongst the Triticeae tribe can be exploited to improve wheat photosynthesis and crop productivity. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  4. Video Review: Better Places: The Hmong of Rhode Island a Generation Later

    Directory of Open Access Journals (Sweden)

    Chia Youyee Vang

    2011-12-01

    Full Text Available This article provides a review of Better Places: a documentary that follows up with Hmong families who were originally part of a film produced in the early 1980s about the resettlement experiences of Hmong refugees in Providence, Rhode Island.

  5. Can net photosynthesis and water relations provide a clue on the ...

    African Journals Online (AJOL)

    user

    2011-02-28

    Feb 28, 2011 ... cuvette of the Licor-6400 portable photosynthesis system (Licor,. Lincoln, NE, USA). The leaf ... We would like to thank KOICA for the financial supoort. We thank the KOTUCOP (Korea-Tunisian Coperation. Project) research ...

  6. Rhode Island Flood Plain Management Services; Bench & Reference Mark Catalogue Portsmouth, Newport and Warwick, Rhode Island

    National Research Council Canada - National Science Library

    Hatfield, Christopher

    1994-01-01

    This study, which developed a catalog of bench and reference marks for several communities in Rhode Island, was conducted by the Long Range Planning Branch, Planning Directorate, New England Division, U.S...

  7. Photosynthesis solutions to enhance productivity.

    Science.gov (United States)

    Foyer, Christine H; Ruban, Alexander V; Nixon, Peter J

    2017-09-26

    The concept that photosynthesis is a highly inefficient process in terms of conversion of light energy into biomass is embedded in the literature. It is only in the past decade that the processes limiting photosynthetic efficiency have been understood to an extent that allows a step change in our ability to manipulate light energy assimilation into carbon gain. We can therefore envisage that future increases in the grain yield potential of our major crops may depend largely on increasing the efficiency of photosynthesis. The papers in this issue provide new insights into the nature of current limitations on photosynthesis and identify new targets that can be used for crop improvement, together with information on the impacts of a changing environment on the productivity of photosynthesis on land and in our oceans.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Author(s).

  8. Photosynthesis and Bioconversion

    International Nuclear Information System (INIS)

    Broda, E.

    1983-01-01

    This text summarises a talk held by Engelbert Broda at a conference on non-convential energy sources. The talk about photosynthesis and bioconversion is devided in 6 sections: the great physicist and photosynthesis; the influence of photosynthesis on the biosphere (in the past, present and future); the light reactions in photosynthesis; the dark reactions in photosynthesis; bioconversion; respiration and photorespiration. (nowak)

  9. Can net photosynthesis and water relations provide a clue on the ...

    African Journals Online (AJOL)

    Net photosynthesis, sap flow density (SFD) and water use efficiency (WUE) were measured in a Quercus suber forest in north Tunisia in an attempt to explain the forest decline. In general, sap flow was positively related to light intensity and water loss, indicating that high light intensities can increase the SFD up to the ...

  10. A Precipitation-Runoff Model for the Blackstone River Basin, Massachusetts and Rhode Island

    Science.gov (United States)

    Barbaro, Jeffrey R.; Zarriello, Phillip J.

    2007-01-01

    Survey cooperative streamflow-gaging network, and at seven partial-record stations installed in 2004 for this study. Because the model-calibration period preceded data collection at the partial-record stations, a continuous streamflow record was estimated at these stations by correlation with flows at nearby continuous-record stations to provide additional streamflow data for model calibration. Water-use information was compiled for 1996-2001 and included municipal and commercial/industrial withdrawals, private residential withdrawals, golf-course withdrawals, municipal wastewater-return flows, and on-site septic effluent return flows. Streamflow depletion was computed for all time-varying ground-water withdrawals prior to simulation. Water-use data were included in the model to represent the net effect of water use on simulated hydrographs. Consequently, the calibrated values of the hydrologic parameters better represent the hydrologic response of the basin to precipitation. The model was calibrated for 1997-2001 to coincide with the land-use and water-use data compiled for the study. Four long-term stations (Nipmuc River near Harrisville, Rhode Island; Quinsigamond River at North Grafton, Massachusetts; Branch River at Forestdale, Rhode Island; and Blackstone River at Woonsocket, Rhode Island) that monitor flow at 3.3, 5.4, 19, and 88 percent of the total basin area, respectively, provided the primary model-calibration points. Hydrographs, scatter plots, and flow-duration curves of observed and simulated discharges, along with various model-fit statistics, indicated that the model performed well over a range of hydrologic conditions. For example, the total runoff volume for the calibration period simulated at the Nipmuc River near Harrisville, Rhode Island; Quinsigamond River at North Grafton, Massachusetts; Branch River at Forestdale, Rhode Island; and Blackstone River at Woonsocket, Rhode Island streamflow-gaging stations differed from the observed runoff v

  11. Carotenoids and Photosynthesis.

    Science.gov (United States)

    Hashimoto, Hideki; Uragami, Chiasa; Cogdell, Richard J

    2016-01-01

    Carotenoids are ubiquitous and essential pigments in photosynthesis. They absorb in the blue-green region of the solar spectrum and transfer the absorbed energy to (bacterio-)chlorophylls, and so expand the wavelength range of light that is able to drive photosynthesis. This is an example of singlet-singlet energy transfer, and so carotenoids serve to enhance the overall efficiency of photosynthetic light reactions. Carotenoids also act to protect photosynthetic organisms from the harmful effects of excess exposure to light. Triplet-triplet energy transfer from chlorophylls to carotenoids plays a key role in this photoprotective reaction. In the light-harvesting pigment-protein complexes from purple photosynthetic bacteria and chlorophytes, carotenoids have an additional role of structural stabilization of those complexes. In this article we review what is currently known about how carotenoids discharge these functions. The molecular architecture of photosynthetic systems will be outlined first to provide a basis from which to describe carotenoid photochemistry, which underlies most of their important functions in photosynthesis.

  12. Residential Energy Efficiency Potential: Rhode Island

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Eric J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-02

    Energy used by Rhode Island single-family homes that can be saved through cost-effective improvements. Prepared by Eric Wilson and Noel Merket, NREL, and Erin Boyd, U.S. Department of Energy Office of Energy Policy and Systems Analysis.

  13. Scientific information in support of water resource management of the Big River area, Rhode Island

    Science.gov (United States)

    Armstrong, David S.; Masterson, John P.; Robinson, Keith W.; Crawley, Kathleen M.

    2015-01-01

    The Rhode Island Water Resources Board (RIWRB) is concerned that the demand for water may exceed the available public water supply in central and southern Rhode Island. Although water is often assumed to be plentiful in Rhode Island because of abundant rainfall, an adequate supply of water is not always available everywhere in the state during dry periods. Concerns that water demand may exceed supply are greatest during the summer, when lower water levels and increased drought potential combine with seasonal increases in peak water demand (Rhode Island Water Resources Board, 2012). High summer water demands are due to increases in outdoor water use, such as lawn watering and agricultural irrigation, and to increased summer population in coastal areas. Water-supply concerns are particularly acute in central and southern Rhode Island, where groundwater is the primary source of drinking water.

  14. Regulation in photosynthesis

    International Nuclear Information System (INIS)

    Heber, U.

    1989-01-01

    This short paper focus on an overall perspective of photosynthesis. The author points out that although much progress has been made into the molecular mechanisms of photosynthesis, the picture is still far from complete. The study of interactions in photosynthesis is important because such a complex process must have regulatory mechanisms. The author also discusses the importance of photosynthesis study in the practical world of survival of man and production of food

  15. Combined multibeam and bathymetry data from Rhode Island Sound and Block Island Sound: a regional perspective

    Science.gov (United States)

    Poppe, Lawrence J.; McMullen, Katherine Y.; Danforth, William W.; Blankenship, Mark R.; Clos, Andrew R.; Glomb, Kimberly A.; Lewit, Peter G.; Nadeau, Megan A.; Wood, Douglas A.; Parker, Castleton E.

    2014-01-01

    Detailed bathymetric maps of the sea floor in Rhode Island and Block Island Sounds are of great interest to the New York, Rhode Island, and Massachusetts research and management communities because of this area's ecological, recreational, and commercial importance. Geologically interpreted digital terrain models from individual surveys provide important benthic environmental information, yet many applications of this information require a geographically broader perspective. For example, individual surveys are of limited use for the planning and construction of cross-sound infrastructure, such as cables and pipelines, or for the testing of regional circulation models. To address this need, we integrated 14 contiguous multibeam bathymetric datasets that were produced by the National Oceanic and Atmospheric Administration during charting operations into one digital terrain model that covers much of Block Island Sound and extends eastward across Rhode Island Sound. The new dataset, which covers over 1244 square kilometers, is adjusted to mean lower low water, gridded to 4-meter resolution, and provided in Universal Transverse Mercator Zone 19, North American Datum of 1983 and geographic World Geodetic Survey of 1984 projections. This resolution is adequate for sea-floor feature and process interpretation but is small enough to be queried and manipulated with standard Geographic Information System programs and to allow for future growth. Natural features visible in the data include boulder lag deposits of winnowed Pleistocene strata, sand-wave fields, and scour depressions that reflect the strength of oscillating tidal currents and scour by storm-induced waves. Bedform asymmetry allows interpretations of net sediment transport. Anthropogenic features visible in the data include shipwrecks and dredged channels. Together the merged data reveal a larger, more continuous perspective of bathymetric topography than previously available, providing a fundamental framework for

  16. Dynamic photosynthesis in different environmental conditions.

    Science.gov (United States)

    Kaiser, Elias; Morales, Alejandro; Harbinson, Jeremy; Kromdijk, Johannes; Heuvelink, Ep; Marcelis, Leo F M

    2015-05-01

    Incident irradiance on plant leaves often fluctuates, causing dynamic photosynthesis. Whereas steady-state photosynthetic responses to environmental factors have been extensively studied, knowledge of dynamic modulation of photosynthesis remains scarce and scattered. This review addresses this discrepancy by summarizing available data and identifying the research questions necessary to advance our understanding of interactions between environmental factors and dynamic behaviour of photosynthesis using a mechanistic framework. Firstly, dynamic photosynthesis is separated into sub-processes related to proton and electron transport, non-photochemical quenching, control of metabolite flux through the Calvin cycle (activation states of Rubisco and RuBP regeneration, and post-illumination metabolite turnover), and control of CO₂ supply to Rubisco (stomatal and mesophyll conductance changes). Secondly, the modulation of dynamic photosynthesis and its sub-processes by environmental factors is described. Increases in ambient CO₂ concentration and temperature (up to ~35°C) enhance rates of photosynthetic induction and decrease its loss, facilitating more efficient dynamic photosynthesis. Depending on the sensitivity of stomatal conductance, dynamic photosynthesis may additionally be modulated by air humidity. Major knowledge gaps exist regarding environmental modulation of loss of photosynthetic induction, dynamic changes in mesophyll conductance, and the extent of limitations imposed by stomatal conductance for different species and environmental conditions. The study of mutants or genetic transformants for specific processes under various environmental conditions could provide significant progress in understanding the control of dynamic photosynthesis. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  17. Identification and characterization of nuclear genes involved in photosynthesis in Populus

    Science.gov (United States)

    2014-01-01

    Background The gap between the real and potential photosynthetic rate under field conditions suggests that photosynthesis could potentially be improved. Nuclear genes provide possible targets for improving photosynthetic efficiency. Hence, genome-wide identification and characterization of the nuclear genes affecting photosynthetic traits in woody plants would provide key insights on genetic regulation of photosynthesis and identify candidate processes for improvement of photosynthesis. Results Using microarray and bulked segregant analysis strategies, we identified differentially expressed nuclear genes for photosynthesis traits in a segregating population of poplar. We identified 515 differentially expressed genes in this population (FC ≥ 2 or FC ≤ 0.5, P photosynthesis by the nuclear genome mainly involves transport, metabolism and response to stimulus functions. Conclusions This study provides new genome-scale strategies for the discovery of potential candidate genes affecting photosynthesis in Populus, and for identification of the functions of genes involved in regulation of photosynthesis. This work also suggests that improving photosynthetic efficiency under field conditions will require the consideration of multiple factors, such as stress responses. PMID:24673936

  18. Libraries, The locations and contact information for academic, private and public libraries in Rhode Island. The intention of this dataset was to provide an overview of data. Additional information pertinent to the state is also available from the RI Department of, Published in 2007, 1:4800 (1in=400ft) scale, Rhode Island and Providence Plantations.

    Data.gov (United States)

    NSGIC State | GIS Inventory — Libraries dataset current as of 2007. The locations and contact information for academic, private and public libraries in Rhode Island. The intention of this dataset...

  19. The Rhode Island "Washington": Meaning Making in Social Studies through Art History

    Science.gov (United States)

    Piro, Joseph M.

    2005-01-01

    The Rhode Island State House in Providence is an imposing structure. It is also an architecturally significant one. Built of white Georgia marble between 1895 and 1904, it has one of only four self-supporting marble covered domes found in the world. It was placed in the National Register of Historic Places in 1971. Looking around, one encounters…

  20. Availability of ground water in the Blackstone River area Rhode Island and Massachusetts

    Science.gov (United States)

    Johnston, Herbert E.; Dickerman, David C.

    1974-01-01

    The Blackstone River study area covers 83 square miles of northern Rhode Island and 5 square miles of adjacent Massachusetts (fig. 1). It includes parts of the Blackstone, Moshassuck, and Tenmile River basins, and a coastal area that drains to the brackish Seekonk and Providence Rivers. In Rhode Island, all or parts of the suburban towns of Cumberland, Lincoln, North Smithfield, and Smithfield and all or parts of the cities of Central Falls, East Povidence, Pawtucket, Providence, and Woonsocket are within the study area. Also included are parts of the towns Attleboro and North Attleborough in Massachusetts. In 1970, total population was about 240,000, which was equivalent to about one-fourth of the total population of Rhode Island. Fresh water usage in 1970 by public-supply systems and self-supplied industry was about 33 mgd (million gallons per day), which was equal to 22 percent of total fresh water use in Rhode Island for all purposes except generation of electric power (fig. 2). Anticipated increases in population and per capita water requirements are likely to cause the demand for water to more than double within the next 50 years. A significant part of this demand can be met from wells that tap the principal streams. This aquifer yielded an average of 10 mgd in 1970 and is capable of sustaining a much higher yield. The primary objectives of the study were to determine and map the saturated thickness and transmissivity of the stratified-drift aquifer and to assess the potential sustained yield of those parts of the aquifer favorable for large-scale development of water. A secondary objective was to describe ground-water quality and to evaluate the impact of induced infiltration of polluted stream water on the quality of native ground water. This report is based on analysis of drillers' records of more than 700 wells and borings which include 462 lithologic logs; 35 specific-capacity determinations; 12 aquifer tests, including detailed tests at two sites to

  1. Climate changes and photosynthesis

    Directory of Open Access Journals (Sweden)

    G.Sh Tkemaladze

    2016-06-01

    Solar energy is environmentally friendly and its conversion to energy of chemical substances is carried out only by photosynthesis – effective mechanism characteristic of plants. However, microorganism photosynthesis occurs more frequently than higher plant photosynthesis. More than half of photosynthesis taking place on the earth surface occurs in single-celled organisms, especially algae, in particular, diatomic organisms.

  2. Tourism development and impacts: lessons from the Island of Rhodes, Greece

    OpenAIRE

    Pappas, Nikolaos; Tsartas, Paris

    2009-01-01

    During the post Second World War period, the island of Rhodes experienced significant changes at several levels of its economy, society, and environment, associated directly or indirectly with rapid tourism development. The tourism impacts are profound on both locals and visitors. The purpose of this paper is to examine the key informants’ perceptions in Rhodes toward tourism impacts. Moreover it correlates the respondents’ perceptions with the previous studies’ outcomes in the region. Finall...

  3. REWSET: A prototype seismic and tsunami early warning system in Rhodes island, Greece

    Science.gov (United States)

    Papadopoulos, Gerasimos; Argyris, Ilias; Aggelou, Savvas; Karastathis, Vasilis

    2014-05-01

    Tsunami warning in near-field conditions is a critical issue in the Mediterranean Sea since the most important tsunami sources are situated within tsunami wave travel times starting from about five minutes. The project NEARTOWARN (2012-2013) supported by the EU-DG ECHO contributed substantially to the development of new tools for the near-field tsunami early warning in the Mediterranean. One of the main achievements is the development of a local warning system in the test-site of Rhodes island (Rhodes Early Warning System for Earthquakes and Tsunamis - REWSET). The system is composed by three main subsystems: (1) a network of eight seismic early warning devices installed in four different localities of the island, one in the civil protection, another in the Fire Brigade and another two in municipality buildings; (2) two radar-type (ultrasonic) tide-gauges installed in the eastern coastal zine of the island which was selected since research on the historical earthquake and tsunami activity has indicated that the most important, near-field tsunami sources are situated offshore to the east of Rhodes; (3) a crisis Geographic Management System (GMS), which is a web-based and GIS-based application incorporating a variety of thematic maps and other information types. The seismic early warning devices activate by strong (magnitude around 6 or more) earthquakes occurring at distances up to about 100 km from Rhodes, thus providing immediate mobilization of the civil protection. The tide-gauges transmit sea level data, while during the crisis the GMS supports decisions to be made by civil protection. In the near future it is planned the REWSET system to be integrated with national and international systems. REWSET is a prototype which certainly could be developed in other coastal areas of the Mediterranean and beyond.

  4. Estimating the Economic Boost of Marriage Equality in Rhode Island

    OpenAIRE

    Kastanis, Angeliki; Badgett, Lee

    2013-01-01

    Extending marriage rights to same-sex couples in Rhode Island would bring an estimated $7 million to the state and local economy, including $5.5 million in additional wedding spending and $1.5 million in tourism expenditures made by out-of-town guests. Based on Rhode Island’s rates of 7 percent sales tax and 6 percent hotel and lodging tax, $530,000 in tax revenue will be generated for the state in the first three years same-sex couples may marry. The boost in travel spending will generate ap...

  5. Rhode Island ITS/CVO business plan : final report

    Science.gov (United States)

    1998-01-01

    The Rhode Island Intelligent Transportation Systems/Commercial Vehicle Operations (ITS/CVO) Institutional Issues Study completed July 1996, substantiated the need for enhanced efficiency and safety in commercial transportation systems and regulation....

  6. Legislative Districts, Rhode Island Senate Districts; risen07; State legislature district boundaries for the RI State Senate as determined in 2002 and revised in 2004 as designated in Rhode Island General Law 17-11. Corrected for renumbering of districts 9,12,24,and 32 in 2007, Published in 2007, 1:100000 (1in=8333ft) scale, Rhode Island and Providence Plantations.

    Data.gov (United States)

    NSGIC State | GIS Inventory — Legislative Districts dataset current as of 2007. Rhode Island Senate Districts; risen07; State legislature district boundaries for the RI State Senate as determined...

  7. Leaking Underground Tanks in Rhode Island; LUSTs12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset shows the location of storage tanks and associated piping used for petroleum and certain hazardous substances that have experienced leaks as determined...

  8. 76 FR 52656 - Rhode Island Department of Environmental Management; Notice of Preliminary Permit Application...

    Science.gov (United States)

    2011-08-23

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 14211-000] Rhode Island Department of Environmental Management; Notice of Preliminary Permit Application Accepted for Filing and Soliciting Comments, Motions To Intervene, and Competing Applications On June 10, 2011, the Rhode Island Department of Environmental Management...

  9. Contribution of chronic petroleum inputs to Narragansett Bay and Rhode Island Sound sediments

    Energy Technology Data Exchange (ETDEWEB)

    Van Vleet, E S; Quin, J G

    1978-05-01

    Sediment cores from Narragansett Bay and Rhode Island Sound have been analyzed for petroleum hydrocarbons and compared with a relatively unpolluted sediment core from the Gulf of Maine. The sediments were analyzed for unbound hydrocarbons, hydrocarbons bound or closely associated with humic substances, and residual hydrocarbons bound or closely associated with the clay mineral or kerogen matrix. Results indicated that in general 90-100% of the hydrocarbons were in the unbound form and could be easily extracted with organic solvents. The petroleum hydrocarbons decreased with depth at all stations. Biogenic hydrocarbons (nC/sub 25/, nC/sub 27/, nC/sub 29/, and nC/sub 31/) made up an increasingly greater percentage of the total with increasing depth. The hydrocarbons in the Narragansett Bay sediments and near surface Rhode Island Sound sediments strongly resembled the hydrocarbons previously reported for the Providence River and upper Narragansett Bay. These petroleum-like hydrocarbons were shown to be largely introduced to the river and bay through chronic inputs from a municipal wastewater treatment plant. These hydrocarbons then undergo sedimentation throughout the entire bay and into Rhode Island Sound. Preliminary calculations indicate that over 0.2 million t (tonne) of petroleum hydrocarbons may be transported to the marine environment annually from municipal treatment plants. Most of these hydrocarbons appear to accumulate in estuarine and coastal sediments.

  10. Microbial photosynthesis in the harnessing of solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Pirt, S J

    1982-01-01

    The shortage of fossil fuels restricts the world supply of reduced carbon compounds and energy sources. Biotechnology offers the most feasible route to renewing the supplies of reduced carbon compounds. This involves recycling of CO/sub 2/ through photosynthesis. Conventional agriculture has little or no potential for supplying biomass and its derivatives on sufficient scale to offer an alternative to the fossil fuels. The agricultural wastes, on the whole, are intractable to conversion into useful carbon and energy sources and in any case are not available in amounts to provide a significant alternative to the fossil fuels. In contrast, microbial photosynthesis, optimised in photobioreactors, has vast potential to provide organic matter on a scale to match the consumption of fossil fuels. The quantative study of microbial photosynthesis as a biotechnological route to biomass has been neglected. As a result there is a chaos of conflicting data on fundamental parameters, for example, the photosynthetic efficiency of biomass production. New photosynthetic biotechnology with fully controlled continuous-culture systems is providing unequivocal values for the parameters. For the scale-up of microbial photosynthesis a tubular-loop reactor is proposed. (Refs. 14).

  11. One million served: Rhode Island`s recycling facility

    Energy Technology Data Exchange (ETDEWEB)

    Malloy, M.G.

    1997-11-01

    Rhode Island`s landfill and adjacent materials recovery facility (MRF) in Johnston, both owned by the quasi-public Rhode Island Resource Recovery Corp. (RIRRC, Johnston), serve the entire state. The $12-million recycling facility was built in 1989 next to the state`s sole landfill, the Central Landfill, which accepts only in-state trash. The MRF is operated for RIRRC by New England CRInc. (Hampton, N.H.), a unit of Waste Management, Inc. (WMI, Oak Brook, Ill.). It handles a wide variety of materials, from the usual newspaper, cardboard, and mixed containers to new streams such as wood waste, scrap metal, aseptic packaging (milk and juice boxes), and even textiles. State municipalities are in the process of adding many of these new recyclable streams into their curbside collection programs, all of which feed the facility.

  12. Daily xanthophyll cycle photoprotection in developing leaves prior to photosynthesis

    Science.gov (United States)

    M.N. Angelov; Shi-Jean S. Sung; C.C. Black

    1995-01-01

    There is widespread agreement that the xanthophyll cycle provides a major photoprotection system for photosynthesis in green leaves.Indeed this type of photoprotection seem to be ubiquitous for photosynthetic organisms. Photoprotection is provided via a rapid, near 10-13 sec, ability of zeaxanthin (Z) to dissipate excess light energy from photosynthesis because the...

  13. Many Rhodes: Travelling Scholarships and Imperial Citizenship in the British Academic World, 1880-1940

    Science.gov (United States)

    Pietsch, Tamson

    2011-01-01

    Since its Foundation in 1901, the Rhodes Scholarships scheme has been held up as the archetype of a programme designed to foster imperial citizens. However, though impressive in scale, Cecil Rhodes's foundation was not the first to bring colonial students to Britain. Over the course of the previous half-century, governments, universities and…

  14. Investigation of grapevine photosynthesis using hyperspectral techniques and development of hyperspectral band ratio indices sensitive to photosynthesis.

    Science.gov (United States)

    Ozelkan, Emre; Karaman, Muhittin; Candar, Serkan; Coskun, Zafer; Ormeci, Cankut

    2015-01-01

    The photosynthetic rate of 9 different grapevines were analyzed with simultaneous photosynthesis and spectroradiometric measurements on 08.08.2012 (veraison) and 06.09.2012 (harvest). The wavelengths and spectral regions, which most properly express photosynthetic rate, were determined using correlation and regression analysis. In addition, hyperspectral band ratio (BR) indices sensitive to photosynthesis were developed using optimum band ratio (OBRA) method. The relation of BR results with photosynthesis values are presented with the correlation matrix maps created in this study. The examinations were performed for both specific dates (i.e., veraison and harvest) and also in aggregate (i.e., correlation between total spectra and photosynthesis data). For specific dates wavelength based analysis, the photosynthesis were best determined with -0.929 correlation coefficient (r) 609 nm of yellow region at veraison stage, and -0.870 at 641 nm of red region at harvest stage. For wavelength based aggregate analysis, 640 nm of red region was found to be correlated with 0.921 and -0.867 r values respectively and red edge (RE) (695 nm) was found to be correlated with -0.922 and -0.860 r values, respectively. When BR indices results were analyzed with photosynthetic values for specific dates, -0.987 r with R8../R, at veraison stage and -0.911 r with R696/R944 at harvest stage were found most correlated. For aggregate analysis of BR, common BR presenting great correlation with photosynthesis for both measurements was found to be R632/R971 with -0.974, -0.881 r values, respectively and other R610/R760 with -0.976, -0.879 r values. The final results of this study indicate that the proportion of RE region to a region with direct or indirect correlation with photosynthetic provides information about rate of photosynthesis. With the indices created in this study, the photosynthesis rate of vineyards can be determined using in-situ hyperspectral remote sensing. The findings of this

  15. Rhode Island hurricanes and tropical storms: A fifty-six year summary 1936-1991. Technical memo

    International Nuclear Information System (INIS)

    Vallee, D.R.

    1993-03-01

    The paper was compiled to provide a general overview of all tropical cyclone activity near Rhode Island since 1936. The year of 1936 is arbitrary, chosen mainly to include a 'not so well known' system prior to the well documented Great New England Hurricane of 1938. Thirty-one such storms have affected the state in the past 56 years, either making landfall along the coast of southern New England, or passing close enough over the offshore waters to spread tropical storm or hurricane force conditions into the area. The intensities of these systems have ranged from weak, disorganized tropical storms to full fledged major hurricanes. The one feature common to almost all of the storms was a rapid acceleration toward Rhode Island, which greatly reduced the time to prepare and evacuate

  16. Energy conversion in natural and artificial photosynthesis.

    Science.gov (United States)

    McConnell, Iain; Li, Gonghu; Brudvig, Gary W

    2010-05-28

    Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil-fuel dependence has severe consequences, including energy security issues and greenhouse gas emissions. The consequences of fossil-fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and in artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices, including photoelectrochemical cells, for solar energy conversion. 2010 Elsevier Ltd. All rights reserved.

  17. Manganese-based Materials Inspired by Photosynthesis for Water-Splitting

    Directory of Open Access Journals (Sweden)

    Harvey J.M. Hou

    2011-09-01

    Full Text Available In nature, the water-splitting reaction via photosynthesis driven by sunlight in plants, algae, and cyanobacteria stores the vast solar energy and provides vital oxygen to life on earth. The recent advances in elucidating the structures and functions of natural photosynthesis has provided firm framework and solid foundation in applying the knowledge to transform the carbon-based energy to renewable solar energy into our energy systems. In this review, inspired by photosynthesis robust photo water-splitting systems using manganese-containing materials including Mn-terpy dimer/titanium oxide, Mn-oxo tetramer/Nafion, and Mn-terpy oligomer/tungsten oxide, in solar fuel production are summarized and evaluated. Potential problems and future endeavors are also discussed.

  18. Anoxygenic Photosynthesis Controls Oxygenic Photosynthesis in a Cyanobacterium from a Sulfidic Spring

    KAUST Repository

    Klatt, Judith M.; Alnajjar, Mohammad Ahmad; Yilmaz, Pelin; Lavik, Gaute; de Beer, Dirk; Polerecky, Lubos

    2015-01-01

    Before the Earth's complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium, Pseudanabaena strain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism's affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However, Pseudanabaena FS39 additionally assimilated NO3 - during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life.

  19. Anoxygenic Photosynthesis Controls Oxygenic Photosynthesis in a Cyanobacterium from a Sulfidic Spring

    KAUST Repository

    Klatt, Judith M.

    2015-03-15

    Before the Earth\\'s complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium, Pseudanabaena strain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism\\'s affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However, Pseudanabaena FS39 additionally assimilated NO3 - during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life.

  20. The timber resources of Rhode Island

    Science.gov (United States)

    Roland H. Ferguson; John R. McGuire; John R. McGuire

    1957-01-01

    This is a report on the first comprehensive survey ever made of the timber resources of Rhode Island. It shows, for the years 1952 and 1953, the area and condition of the forest land, the volume and quality of standing timber, the rates of timber growth and mortality, and the extent of timber cutting for forest products. The survey was made by the Forest Service as...

  1. Photosynthesis in the Archean era.

    Science.gov (United States)

    Olson, John M

    2006-05-01

    The earliest reductant for photosynthesis may have been H2. The carbon isotope composition measured in graphite from the 3.8-Ga Isua Supercrustal Belt in Greenland is attributed to H2-driven photosynthesis, rather than to oxygenic photosynthesis as there would have been no evolutionary pressure for oxygenic photosynthesis in the presence of H2. Anoxygenic photosynthesis may also be responsible for the filamentous mats found in the 3.4-Ga Buck Reef Chert in South Africa. Another early reductant was probably H2S. Eventually the supply of H2 in the atmosphere was likely to have been attenuated by the production of CH4 by methanogens, and the supply of H2S was likely to have been restricted to special environments near volcanos. Evaporites, possible stromatolites, and possible microfossils found in the 3.5-Ga Warrawoona Megasequence in Australia are attributed to sulfur-driven photosynthesis. Proteobacteria and protocyanobacteria are assumed to have evolved to use ferrous iron as reductant sometime around 3.0 Ga or earlier. This type of photosynthesis could have produced banded iron formations similar to those produced by oxygenic photosynthesis. Microfossils, stromatolites, and chemical biomarkers in Australia and South Africa show that cyanobacteria containing chlorophyll a and carrying out oxygenic photosynthesis appeared by 2.8 Ga, but the oxygen level in the atmosphere did not begin to increase until about 2.3 Ga.

  2. Improving Photosynthesis

    Science.gov (United States)

    Evans, John R.

    2013-01-01

    Photosynthesis is the basis of plant growth, and improving photosynthesis can contribute toward greater food security in the coming decades as world population increases. Multiple targets have been identified that could be manipulated to increase crop photosynthesis. The most important target is Rubisco because it catalyses both carboxylation and oxygenation reactions and the majority of responses of photosynthesis to light, CO2, and temperature are reflected in its kinetic properties. Oxygenase activity can be reduced either by concentrating CO2 around Rubisco or by modifying the kinetic properties of Rubisco. The C4 photosynthetic pathway is a CO2-concentrating mechanism that generally enables C4 plants to achieve greater efficiency in their use of light, nitrogen, and water than C3 plants. To capitalize on these advantages, attempts have been made to engineer the C4 pathway into C3 rice (Oryza sativa). A simpler approach is to transfer bicarbonate transporters from cyanobacteria into chloroplasts and prevent CO2 leakage. Recent technological breakthroughs now allow higher plant Rubisco to be engineered and assembled successfully in planta. Novel amino acid sequences can be introduced that have been impossible to reach via normal evolution, potentially enlarging the range of kinetic properties and breaking free from the constraints associated with covariation that have been observed between certain kinetic parameters. Capturing the promise of improved photosynthesis in greater yield potential will require continued efforts to improve carbon allocation within the plant as well as to maintain grain quality and resistance to disease and lodging. PMID:23812345

  3. Anoxygenic photosynthesis controls oxygenic photosynthesis in a cyanobacterium from a sulfidic spring.

    Science.gov (United States)

    Klatt, Judith M; Al-Najjar, Mohammad A A; Yilmaz, Pelin; Lavik, Gaute; de Beer, Dirk; Polerecky, Lubos

    2015-03-01

    Before the Earth's complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium, Pseudanabaena strain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism's affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However, Pseudanabaena FS39 additionally assimilated NO3 (-) during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  4. Five Lectures on Photosynthesis

    International Nuclear Information System (INIS)

    Broda, E.

    1979-01-01

    These five lectures were held by E. Broda during the International Symposium on Alternative Energies, in September 1979. Lecture 1 – The Great Physicists and Photosynthesis; Lecture 2 – The Influence of Photosynthesis on the Biosphere. Past, Present and Future; Lecture 3 – The Origin of Photosynthesis; Lecture 4 – The Evolution from Photosynthetic Bacteria to Plants; Lecture 5 – Respiration and Photorespiration. (nowak)

  5. Final report, Feedback limitations of photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Sharkey, Thomas D.

    1999-07-22

    Final report of research on carbon metabolism of photosynthesis. The feedback from carbon metabolism to primary photosynthetic processes is summarized, and a comprehensive list of published scientific papers is provided.

  6. The Montessori Experiment in Rhode Island (1913-1940): Tracing Theory to Implementation over 25 Years

    Science.gov (United States)

    Zoll, Susan

    2017-01-01

    This article highlights archived documents pertaining to a 25-year experimental classroom implemented by Clara Craig, then supervisor of training at the Rhode Island Normal School. Craig is notable as she was the only participant in the first International Montessori Training Course in Rome, Italy, in 1913, to gain approval from the Rhode Island…

  7. Feeding Dairy Cows to Increase Performance on Rhodes Grass Ley

    International Nuclear Information System (INIS)

    Irungu, K.R.G.; Mbugua, P.N.

    1999-01-01

    Majority of dairy farmers in Kenya produce milk from cows fed on roughage. The cow performance follows seasonal variability in quality and quantity of roughage. The objective of the current study was to increase cow performance and maintain productivity of a rhodes grass (chloris gayana) ley. Twenty-four Freisian cows in their second to third lactation were strip grazed on fertilized irrigated Rhodes grass at a stocking rate of 0.034 ha per cow. Four dietary groups of six cows were allocated to one of our diets. one group got no dairy meal while the other three groups were supplemented at a 1kg of dairy meal per 10, 5 and 2.5 kg of 4% fat corrected milk dairy. this amount to 0, 386, 750 and 1542 kg dairy meal (89.4%, DM, 93.7 OM, 16.8, CP and CF) during the lactation. during the 43 - week lactation, records on pasture nutrient yield, nutrient intake, milk yield, liveweight, reproduction and subsequent calf birth weight were collected. The Rhodes grass ley produced 20.7 (ranging from 16.7 to 28.7) t of dry matter (DM) per hectare and cows harvested 16.0 (12.0 to 24.0) t during the 43 weeks.The Rhodes grass contained 32.1, 87.7, 10.8, and 32.3% DM, organic matter (OM), crude protein (CP) and crude fiber (CF) respectively. Mean stubble of 4.7 (3.9 to 6.0) t DM per hectare was left at pasture. Feeding dairy meals significantly increased (P 0.05) affect batter fat content (3.78 to 3.96%). It maintained (P > 0.05) cow liveweight and increased (P < 0.05) calf birth weight from 32.7 to 37.2 kg. Feeding dairy meal did not affect oestrus cycling. Extreme supplementation, 1542 kg dairy meal, decreased (P < 0.05) fertility. Insemination per conception and calving interval increased (P < 0.05) from 1.5 to 3.5 and 522 days. The findings in the current study show that pasture yield can be increased by over 590% dry matter from 3.5 t obtained from natural pasture containing Kikuyu and Star grasses. The Rhodes grass yield can be increased to 232% of national average yield of 1300

  8. Fruit photosynthesis in Satsuma mandarin.

    Science.gov (United States)

    Hiratsuka, Shin; Suzuki, Mayu; Nishimura, Hiroshi; Nada, Kazuyoshi

    2015-12-01

    To clarify detailed characteristics of fruit photosynthesis, possible gas exchange pathway and photosynthetic response to different environments were investigated in Satsuma mandarin (Citrus unshiu). About 300 mm(-2) stomata were present on fruit surface during young stages (∼10-30 mm diameter fruit) and each stoma increased in size until approximately 88 days after full bloom (DAFB), while the stomata collapsed steadily thereafter; more than 50% stomata deformed at 153 DAFB. The transpiration rate of the fruit appeared to match with stoma development and its intactness rather than the density. Gross photosynthetic rate of the rind increased gradually with increasing CO2 up to 500 ppm but decreased at higher concentrations, which may resemble C4 photosynthesis. In contrast, leaf photosynthesis increased constantly with CO2 increment. Although both fruit and leaf photosynthesis were accelerated by rising photosynthetic photon flux density (PPFD), fruit photosynthesis was greater under considerably lower PPFD from 13.5 to 68 μmolm(-2)s(-1). Thus, Satsuma mandarin fruit appears to incorporate CO2 through fully developed and non-collapsed stomata, and subject it to fruit photosynthesis, which may be characterized as intermediate status among C3, C4 and shade plant photosynthesis. The device of fruit photosynthesis may develop differently from its leaf to capture CO2 efficiently. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Teaching Photosynthesis with ELL Students

    Science.gov (United States)

    Piper, Susan; Shaw, Edward Lewis, Jr.

    2010-01-01

    Although the teaching of photosynthesis occurs yearly in elementary classrooms, one thing that makes it challenging is the inclusion of English language learners (ELLs). This article presents several activities for teaching and assessing of photosynthesis in a third grade classroom. The activities incorporate the photosynthesis content, teaching…

  10. The Evolution of Photosynthesis

    International Nuclear Information System (INIS)

    Broda, E.

    1976-01-01

    This Review was written by Engelbert Broda, an Austrian Chemist and Physicist, on February the 10th 1976. The merits of the inductive and the deductive approach in tracing the pathways of evolution are discussed. Using the latter approach, it is concluded that photosynthesis followed fermentation as a method of obtaining energy-rich compounds, especially ATP. Photosynthesis probably arose by utilization of membranes for bioenergetic processes. Originally photosynthesis served photophosphorylation (ATP production), later reducing power was also made, either by open-ended, light-powered, electron flow or driven by ATP; ultimate electron donors were at first hydrogen or sulfur compounds, and later water, the last-named capability Was acquired by prokaryotic algae the earliest plants, similar to the recent blue-greens. When free oxygen entered the atmosphere for the first time, various forms of respiration (oxidative phosphorylation) became possible. Mechanistically, respiration evolved from photosynthesis (‘conversion hypotheses’). Prokaryotic algae are probably the ancestors of the chloroplasts in the eukaryotes, In the evolution of the eukaryotes, not much change in the basic processes of photosynthesis occurred.(author)

  11. Photosynthesis in Hydrogen-Dominated Atmospheres

    Science.gov (United States)

    Bains, William; Seager, Sara; Zsom, Andras

    2014-01-01

    The diversity of extrasolar planets discovered in the last decade shows that we should not be constrained to look for life in environments similar to early or present-day Earth. Super-Earth exoplanets are being discovered with increasing frequency, and some will be able to retain a stable, hydrogen-dominated atmosphere. We explore the possibilities for photosynthesis on a rocky planet with a thin H2-dominated atmosphere. If a rocky, H2-dominated planet harbors life, then that life is likely to convert atmospheric carbon into methane. Outgassing may also build an atmosphere in which methane is the principal carbon species. We describe the possible chemical routes for photosynthesis starting from methane and show that less energy and lower energy photons could drive CH4-based photosynthesis as compared with CO2-based photosynthesis. We find that a by-product biosignature gas is likely to be H2, which is not distinct from the hydrogen already present in the environment. Ammonia is a potential biosignature gas of hydrogenic photosynthesis that is unlikely to be generated abiologically. We suggest that the evolution of methane-based photosynthesis is at least as likely as the evolution of anoxygenic photosynthesis on Earth and may support the evolution of complex life. PMID:25411926

  12. Photosynthesis in Hydrogen-Dominated Atmospheres

    Directory of Open Access Journals (Sweden)

    William Bains

    2014-11-01

    Full Text Available The diversity of extrasolar planets discovered in the last decade shows that we should not be constrained to look for life in environments similar to early or present-day Earth. Super-Earth exoplanets are being discovered with increasing frequency, and some will be able to retain a stable, hydrogen-dominated atmosphere. We explore the possibilities for photosynthesis on a rocky planet with a thin H2-dominated atmosphere. If a rocky, H2-dominated planet harbors life, then that life is likely to convert atmospheric carbon into methane. Outgassing may also build an atmosphere in which methane is the principal carbon species. We describe the possible chemical routes for photosynthesis starting from methane and show that less energy and lower energy photons could drive CH4-based photosynthesis as compared with CO2-based photosynthesis. We find that a by-product biosignature gas is likely to be H2, which is not distinct from the hydrogen already present in the environment. Ammonia is a potential biosignature gas of hydrogenic photosynthesis that is unlikely to be generated abiologically. We suggest that the evolution of methane-based photosynthesis is at least as likely as the evolution of anoxygenic photosynthesis on Earth and may support the evolution of complex life.

  13. New Orleans on His Mind: A Rhode Island Choral Director Brings Katrina Victims Music--And Hope

    Science.gov (United States)

    Olson, Catherine Applefeld

    2009-01-01

    Westerly, Rhode Island, is a long way from New Orleans. But the physical distance has not stopped David DeAngelis, choral director at Westerly High School, from providing his students with one heck of a lesson: The opportunity to truly connect with others through music. Under DeAngelis' direction, Westerly's various vocal ensembles have held…

  14. Toward a mechanistic modeling of nitrogen limitation for photosynthesis

    Science.gov (United States)

    Xu, C.; Fisher, R. A.; Travis, B. J.; Wilson, C. J.; McDowell, N. G.

    2011-12-01

    photosynthesis rate. Our model can predict the variability of relationship between leaf nitrogen and photosynthesis at different light, CO2 and temperature conditions and thus provides a better understanding of nitrogen limitation for photosynthesis. We expect that our model will improve the prediction accuracy for vegetation growth and thus global carbon cycles under future climate that has not been experienced by the current plants if the model is incorporated in global earth system models.

  15. PHOTOSYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Donald A. [Pennsylvania State Univ., University Park, PA (United States)

    2002-06-21

    The Gordon Research Conference (GRC) on PHOTOSYNTHESIS was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  16. Broadband Wireline Provider Service Summary; BBRI_wirelineSum12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of broadband Internet access in Rhode Island via all wireline technologies assessed by Broadband Rhode Island. Broadband...

  17. 77 FR 68797 - Rhode Island; Emergency and Related Determinations

    Science.gov (United States)

    2012-11-16

    ... Hurricane Sandy beginning on October 26, 2012, and continuing, are of sufficient severity and magnitude to... emergency. The following areas of the State of Rhode Island have been designated as adversely affected by...; 97.048, Disaster Housing Assistance to Individuals and Households In Presidentially Declared Disaster...

  18. Artificial Photosynthesis: Beyond Mimicking Nature

    International Nuclear Information System (INIS)

    Dau, Holger; Fujita, Etsuko; Sun, Licheng

    2017-01-01

    In this Editorial, Guest Editors Holger Dau, Etsuko Fujita, and Licheng Sun introduce the Special Issue of ChemSusChem on “Artificial Photosynthesis for Sustainable Fuels”. Here, they discuss the need for non-fossil based fuels, introduce both biological and artificial photosynthesis, and outline various important concepts in artificial photosynthesis, including molecular and solid-state catalysts for water oxidation and hydrogen evolution, catalytic CO 2 reduction, and photoelectrochemical systems.

  19. How Will Rhode Island's New Hybrid Pension Plan Affect Teachers? A Report of the Public Pension Project

    Science.gov (United States)

    Johnson, Richard W.; Butrica, Barbara A.; Haaga, Owen; Southgate, Benjamin G.

    2014-01-01

    In 2011 Rhode Island replaced the stand-alone defined benefit pension plan it provided to state employees with a hybrid plan that reduced the defined benefit component and added a 401(k)-type, defined contribution component. Although controversial, the new hybrid plan will boost retirement incomes for most of the states public school teachers. Our…

  20. Annual cycle of Scots pine photosynthesis

    Directory of Open Access Journals (Sweden)

    P. Hari

    2017-12-01

    Full Text Available Photosynthesis, i.e. the assimilation of atmospheric carbon to organic molecules with the help of solar energy, is a fundamental and well-understood process. Here, we connect theoretically the fundamental concepts affecting C3 photosynthesis with the main environmental drivers (ambient temperature and solar light intensity, using six axioms based on physiological and physical knowledge, and yield straightforward and simple mathematical equations. The light and carbon reactions in photosynthesis are based on the coherent operation of the photosynthetic machinery, which is formed of a complicated chain of enzymes, membrane pumps and pigments. A powerful biochemical regulation system has emerged through evolution to match photosynthesis with the annual cycle of solar light and temperature. The action of the biochemical regulation system generates the annual cycle of photosynthesis and emergent properties, the state of the photosynthetic machinery and the efficiency of photosynthesis. The state and the efficiency of the photosynthetic machinery is dynamically changing due to biosynthesis and decomposition of the molecules. The mathematical analysis of the system, defined by the very fundamental concepts and axioms, resulted in exact predictions of the behaviour of daily and annual patterns in photosynthesis. We tested the predictions with extensive field measurements of Scots pine (Pinus sylvestris L. photosynthesis on a branch scale in northern Finland. Our theory gained strong support through rigorous testing.

  1. Annual cycle of Scots pine photosynthesis

    Science.gov (United States)

    Hari, Pertti; Kerminen, Veli-Matti; Kulmala, Liisa; Kulmala, Markku; Noe, Steffen; Petäjä, Tuukka; Vanhatalo, Anni; Bäck, Jaana

    2017-12-01

    Photosynthesis, i.e. the assimilation of atmospheric carbon to organic molecules with the help of solar energy, is a fundamental and well-understood process. Here, we connect theoretically the fundamental concepts affecting C3 photosynthesis with the main environmental drivers (ambient temperature and solar light intensity), using six axioms based on physiological and physical knowledge, and yield straightforward and simple mathematical equations. The light and carbon reactions in photosynthesis are based on the coherent operation of the photosynthetic machinery, which is formed of a complicated chain of enzymes, membrane pumps and pigments. A powerful biochemical regulation system has emerged through evolution to match photosynthesis with the annual cycle of solar light and temperature. The action of the biochemical regulation system generates the annual cycle of photosynthesis and emergent properties, the state of the photosynthetic machinery and the efficiency of photosynthesis. The state and the efficiency of the photosynthetic machinery is dynamically changing due to biosynthesis and decomposition of the molecules. The mathematical analysis of the system, defined by the very fundamental concepts and axioms, resulted in exact predictions of the behaviour of daily and annual patterns in photosynthesis. We tested the predictions with extensive field measurements of Scots pine (Pinus sylvestris L.) photosynthesis on a branch scale in northern Finland. Our theory gained strong support through rigorous testing.

  2. Photosynthesis in high definition

    Science.gov (United States)

    Hilton, Timothy W.

    2018-01-01

    Photosynthesis is the foundation for almost all known life, but quantifying it at scales above a single plant is difficult. A new satellite illuminates plants' molecular machinery at much-improved spatial resolution, taking us one step closer to combined `inside-outside' insights into large-scale photosynthesis.

  3. The Rhodes Scholarship in the Current Era of Student Activism: What Do We Consider "Prestigious" and Who Benefits?

    Science.gov (United States)

    Adam, LeAnn

    2016-01-01

    Contemporary student activism has revealed deep feelings of alienation on college campuses, prompting strong reactions to current and historical racial injustice, including the history of Cecil Rhodes. Can advisors promote restorative justice by encouraging reflection upon privileges afforded to Rhodes scholars and their responsibility to address…

  4. General lighting requirements for photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, D.R. [Univ. of Dayton, OH (United States)

    1994-12-31

    A review of the general lighting requirements for photosynthesis reveals that four aspects of light are important: irradiance, quality, timing and duration. These properties of light affect photosynthesis by providing the energy that drives carbon assimilation as well as by exerting control over physiology, structure and morphology of plants. Irradiance, expressed as energy flux, W m{sup -2}, or photon irradiance, {mu}mol m{sup -2} s{sup -1}, determines the rate at which energy is being delivered to the photosynthetic reaction centers. Spectral quality, the wavelength composition of light, is important because photons differ in their probability of being absorbed by the light harvesting complex and hence their ability to drive carbon assimilation. Also the various light receptors for light-mediated regulation of plant form and physiology have characteristic absorption spectra and hence photons differ in their effectiveness for eliciting responses. Duration is important because both carbon assimilation and regulation are affected by the total energy or integrated irradiance delivered during a given period. Many processes associated with photosynthesis are time-dependent, increasing or decreasing with duration. Timing is important because the effectiveness of light in the regulation of plant processes varies with the phase of the diumal cycle as determined by the plant`s time-measuring mechanisms.

  5. 2011 Photosynthesis Gordon Research Conference & Seminar (June 11-17, 2011, Davidson College, Davidson, North Carolina)

    Energy Technology Data Exchange (ETDEWEB)

    Prof. Krishna Niyogi

    2011-06-17

    Photosynthesis is the biological process that converts solar energy into chemical energy. Elucidation of the mechanisms of photosynthetic energy conversion at a molecular level is fundamentally important for understanding the biology of photosynthetic organisms, for optimizing biological solar fuels production, and for developing biologically inspired approaches to solar energy conversion. The 2011 Gordon Conference on Photosynthesis will present cutting-edge research focusing on the biochemical aspects of photosynthesis, including: (1) structure, assembly, and function of photosynthetic complexes; (2) the mechanism of water splitting by PSII; (3) light harvesting and quenching; (4) alternative electron transport pathways; (5) biosynthesis of pigments and cofactors; and (6) improvement of photosynthesis for bioenergy and food production. Reflecting the interdisciplinary nature of photosynthesis research, a diverse group of invited speakers will represent a variety of scientific approaches to investigate photosynthesis, such as biochemistry, molecular genetics, structural biology, systems biology, and spectroscopy. Highly interactive poster sessions provide opportunities for graduate students and postdocs to present their work and exchange ideas with leaders in the field. One of the highlights of the Conference is a session featuring short talks by junior investigators selected from the poster presentations. The collegial atmosphere of the Photosynthesis GRC, with programmed discussion sessions as well as informal gatherings in the afternoons and evenings, enables participants to brainstorm, exchange ideas, and forge new collaborations. For the second time, this Conference will be immediately preceded by a Gordon Research Seminar on Photosynthesis (June 11-12, 2011, at the same location), with a focus on 'Photosynthesis, Bioenergy, and the Environment.' The GRS provides an additional opportunity for graduate students and postdocs to present their research

  6. Environmental management of mosquito-borne viruses in Rhode Island

    Science.gov (United States)

    Ginsberg, Howard S.; Gettman, Alan; Becker, Elisabeth; Bandyopadhyay, Ananda S.; LeBrun, Roger A.

    2013-01-01

    West Nile Virus (WNV) and Eastern Equine Encephalitis Virus (EEEV) are both primarily bird viruses, which can be transmitted by several mosquito species. Differences in larval habitats, flight, and biting patterns of the primary vector species result in substantial differences in epidemiology, with WNV more common, primarily occurring in urban areas, and EEEV relatively rare, typically occurring near swamp habitats. The complex transmission ecology of these viruses complicates prediction of disease outbreaks. The Rhode Island Department of Environmental Management (DEM) and Department of Health (DoH) provide prevention assistance to towns and maintain a mosquito surveillance program to identify potential disease risk. Responses to potential outbreaks follow a protocol based on surveillance results, assessment of human risk, and technical consultation.

  7. Violence Against Women: Injuries and Deaths in Rhode Island Yongwen Jiang, PhD; Deborah Debare, MMHS; Lynne-Marie Shea, BA; Samara Viner-Brown, MS.

    Science.gov (United States)

    Jiang, Yongwen; DeBare, Deborah; Shea, Lynne-Marie; Viner-Brown, Samara

    2017-12-01

    Violence against women is a public health issue. Monitoring assault-related injury and homicide death among women is imperative for understanding this public health issue. We used data from the 2014 Rhode Island emergency department (ED), hospital discharge (HD), and 2004-2014 Rhode Island violent death reporting system (RIVDRS) to provide a broad picture for violence against women injuries and deaths in Rhode Island. ED visit and HD data show that the majority of female assault injuries occurred among women aged 25-44, resided in the core cities, and had public insurance. RIVDRS data showed that over half of the homicides among women were aged 25-64; nearly two in five were non-Hispanic black or Hispanic. Precipitating circumstances include intimate partner violence, a preceding argument or a conflict, and precipitated by another crime. Evidence-informed interventions need to target high-risk populations and urban areas to effectively reduce violence against women. [Full article available at http://rimed.org/rimedicaljournal-2017-12.asp].

  8. Collection and analysis of remotely sensed data from the Rhode River Estuary Watershed. [ecological parameters of Chesapeake Bay

    Science.gov (United States)

    Jenkins, D. W.

    1972-01-01

    NASA chose the watershed of Rhode River, a small sub-estuary of the Bay, as a representative test area for intensive studies of remote sensing, the results of which could be extrapolated to other estuarine watersheds around the Bay. A broad program of ecological research was already underway within the watershed, conducted by the Smithsonian Institution's Chesapeake Bay Center for Environmental Studies (CBCES) and cooperating universities. This research program offered a unique opportunity to explore potential applications for remote sensing techniques. This led to a joint NASA-CBCES project with two basic objectives: to evaluate remote sensing data for the interpretation of ecological parameters, and to provide essential data for ongoing research at the CBCES. A third objective, dependent upon realization of the first two, was to extrapolate photointerpretive expertise gained at the Rhode River watershed to other portions of the Chesapeake Bay.

  9. The Myth of the Citizen Soldier: Rhode Island Provincial Soldiers in the French and Indian War

    Science.gov (United States)

    2016-06-10

    14 Revolution, is an excellent account of social, economic, and political factors in colonial America that influenced the concept of the citizen ...THE MYTH OF THE CITIZEN -SOLDIER: RHODE ISLAND PROVINCIAL SOLDIERS IN THE FRENCH AND INDIAN WAR A thesis presented to the...From - To) AUG 2015 – JUN 2016 4. TITLE AND SUBTITLE The Myth of the Citizen Soldier: Rhode Island Provincial Soldiers in the French and Indian War

  10. Promoting Independence in Rhode Island: Weatherization Assistance Close-Up Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    D& R International

    2001-10-10

    Rhode Island demonstrates its commitment to technology and efficiency through the Weatherization Program. Weatherization uses advanced technologies and techniques to reduce energy costs for low-income families by increasing the energy efficiency of their homes.

  11. Chronic interstitial lung disease in nylon flocking industry workers--Rhode Island, 1992-1996.

    Science.gov (United States)

    1997-09-26

    Interstitial lung disease (ILD) occurs infrequently; some cases are attributed to sarcoidosis, pulmonary hemorrhage syndromes, connective tissue diseases, hypersensitivity pneumonitis, drugs, radiation, and mineral dusts (e.g., silica or asbestos). However, most cases of ILD are of uncertain classification or etiology. This report describes preliminary findings of the investigation in Rhode Island of an outbreak of ILD among workers involved in the manufacture of finely cut nylon (flock) and flocked fabric (used for upholstery, clothing, and automobiles); the findings provide evidence of a newly recognized occupational illness.

  12. Analysis of Offshore Wind Energy Leasing Areas for the Rhode Island/Massachusetts Wind Energy Area

    Energy Technology Data Exchange (ETDEWEB)

    Musial, W.; Elliott, D.; Fields, J.; Parker, Z.; Scott, G.

    2013-04-01

    The National Renewable Energy Laboratory (NREL), under an interagency agreement with the Bureau of Ocean Energy Management (BOEM), is providing technical assistance to BOEM on the identification and delineation of offshore leasing areas for offshore wind energy development within the Atlantic Coast Wind Energy Areas (WEAs) established by BOEM in 2012. This report focuses on NREL's evaluation of BOEM's Rhode Island/Massachusetts (RIMA) WEA leasing areas. The objective of the NREL evaluation was to assess the proposed delineation of the two leasing areas and determine if the division is reasonable and technically sound. Additionally, the evaluation aimed to identify any deficiencies in the delineation. As part of the review, NREL performed the following tasks: 1. Performed a limited review of relevant literature and RIMA call nominations. 2. Executed a quantitative analysis and comparison of the two proposed leasing areas 3. Conducted interviews with University of Rhode Island (URI) staff involved with the URI Special Area Management Plan (SAMP) 4. Prepared this draft report summarizing the key findings.

  13. LIDAR Products, State of Rhode Island: LIDAR for the North East – ARRA and LiDAR for the North East Part II; LiDAR was collected in the Winter and Spring 2011 at a 1 meter or better nominal post spacing (1m GSD) for approximately 1,074 square miles of Rhode Island, whi, Published in 2012, 1:9600 (1in=800ft) scale, Rhode Island and Providence Plantations.

    Data.gov (United States)

    NSGIC State | GIS Inventory — LIDAR Products dataset current as of 2012. State of Rhode Island: LIDAR for the North East – ARRA and LiDAR for the North East Part II; LiDAR was collected in the...

  14. Children's mental health and family functioning in Rhode Island.

    Science.gov (United States)

    Kim, Hyun Hanna K; Viner-Brown, Samara I; Garcia, Jorge

    2007-02-01

    Our objectives were to (a) estimate the prevalence of children's mental health problems, (b) assess family functioning, and (c) investigate the relationship between children's mental health and family functioning in Rhode Island. From the 2003 National Survey of Children's Health, Rhode Island data for children 6 to 17 years of age were used for the analyses (N = 1326). Two aspects of family functioning measures, parental stress and parental involvement, were constructed and were examined by children's mental health problems, as well as other child and family characteristics (child's age, gender, race/ethnicity, special needs, parent's education, income, employment, family structure, number of children, and mother's general and mental health). Bivariate analyses and multivariate logistic regression were used to investigate the relationship. Among Rhode Island children, nearly 1 (19.0%) in 5 had mental health problems, 1 (15.6%) in 6 lived with a highly stressed parent, and one third (32.7%) had parents with low involvement. Bivariate analyses showed that high parental stress and low parental involvement were higher among parents of children with mental health problems than parents of children without those problems (33.2% vs 11.0% and 41.0% vs 30.3%, respectively). In multivariate logistic regression, parents of children with mental health problems had nearly 4 times the odds of high stress compared with parents of children without those problems. When children's mental health problems were severe, the odds of high parental stress were elevated. However, children's mental health was not associated with parental involvement. Children's mental health was strongly associated with parental stress, but it was not associated with parental involvement. The findings indicate that when examining the mental health issues of children, parental mental health and stress must be considered.

  15. Photosynthesis down-regulation precedes carbohydrate accumulation under sink limitation in Citrus.

    Science.gov (United States)

    Nebauer, Sergio G; Renau-Morata, Begoña; Guardiola, José Luis; Molina, Rosa-Victoria

    2011-02-01

    Photosynthesis down-regulation due to an imbalance between sources and sinks in Citrus leaves could be mediated by excessive accumulation of carbohydrates. However, there is limited understanding of the physiological role of soluble and insoluble carbohydrates in photosynthesis regulation and the elements triggering the down-regulation process. In this work, the role of non-structural carbohydrates in the regulation of photosynthesis under a broad spectrum of source-sink relationships has been investigated in the Salustiana sweet orange. Soluble sugar and starch accumulation in leaves, induced by girdling experiments, did not induce down-regulation of the photosynthetic rate in the presence of sinks (fruits). The leaf-to-fruit ratio did not modulate photosynthesis but allocation of photoassimilates to the fruits. The lack of strong sink activity led to a decrease in the photosynthetic rate and starch accumulation in leaves. However, photosynthesis down-regulation due to an excess of total soluble sugars or starch was discarded because photosynthesis and stomatal conductance reduction occurred prior to any significant accumulation of these carbohydrates. Gas exchange and fluorescence parameters suggested biochemical limitations to photosynthesis. In addition, the expression of carbon metabolism-related genes was altered within 24 h when strong sinks were removed. Sucrose synthesis and export genes were inhibited, whereas the expression of ADP-glucose pyrophosphorylase was increased to cope with the excess of assimilates. In conclusion, changes in starch and soluble sugar turnover, but not sugar content per se, could provide the signal for photosynthesis regulation. In these conditions, non-stomatal limitations strongly inhibited the photosynthetic rate prior to any significant increase in carbohydrate levels.

  16. Analysis of Human Trafficking Cases in Rhode Island, 2009-2013

    Directory of Open Access Journals (Sweden)

    Faith Skodmin

    2016-06-01

    Full Text Available This article is an analysis of law enforcement identified cases of human trafficking in Rhode Island from 2009 to 2013. Information was collected from police and court records, prosecutors’ press releases, and reports in the media. During this period, there was one case of forced labor of a domestic worker and six cases of domestic sex trafficking. Many of the characteristics of the Rhode Island cases were consistent with other human trafficking cases in the United States. Discussions of key findings include (a outcomes of a criminal case using a new human trafficking statute on fraud in foreign contracting and a civil suit, (b how online prostitution ads are used to market victims to sex buyers using ethnicity of the victims and age and social standing of the sex buyers, and (c how mothers of victims are involved in locating their daughters and making reports to the police that initiated investigations.

  17. Predicting photosynthesis and transpiration responses to ozone: decoupling modeled photosynthesis and stomatal conductance

    Directory of Open Access Journals (Sweden)

    D. Lombardozzi

    2012-08-01

    Full Text Available Plants exchange greenhouse gases carbon dioxide and water with the atmosphere through the processes of photosynthesis and transpiration, making them essential in climate regulation. Carbon dioxide and water exchange are typically coupled through the control of stomatal conductance, and the parameterization in many models often predict conductance based on photosynthesis values. Some environmental conditions, like exposure to high ozone (O3 concentrations, alter photosynthesis independent of stomatal conductance, so models that couple these processes cannot accurately predict both. The goals of this study were to test direct and indirect photosynthesis and stomatal conductance modifications based on O3 damage to tulip poplar (Liriodendron tulipifera in a coupled Farquhar/Ball-Berry model. The same modifications were then tested in the Community Land Model (CLM to determine the impacts on gross primary productivity (GPP and transpiration at a constant O3 concentration of 100 parts per billion (ppb. Modifying the Vcmax parameter and directly modifying stomatal conductance best predicts photosynthesis and stomatal conductance responses to chronic O3 over a range of environmental conditions. On a global scale, directly modifying conductance reduces the effect of O3 on both transpiration and GPP compared to indirectly modifying conductance, particularly in the tropics. The results of this study suggest that independently modifying stomatal conductance can improve the ability of models to predict hydrologic cycling, and therefore improve future climate predictions.

  18. Rhode Island, Connecticut, New York, and New Jersey ESI: INVERT (Invertebrate Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and terrestrial invertebrate species in coastal Rhode Island, Connecticut, New York,...

  19. Can miscanthus C4 photosynthesis compete with festulolium C3 photosynthesis in a temperate climate?

    DEFF Research Database (Denmark)

    Jiao, Xiurong; Kørup, Kirsten; Andersen, Mathias Neumann

    2017-01-01

    Miscanthus, a perennial grass with C4 photosynthesis, is regarded as a promising energy crop due to its high biomass productivity. Compared with other C4 species, most miscanthus genotypes have high cold tolerances at 14 °C. However, in temperate climates, temperatures below 14 °C are common...... at each temperature level and still maintained photosynthesis after growing for a longer period at 6/4 °C. Only two of five measured miscanthus genotypes increased photosynthesis immediately after the temperature was raised again. The photosynthetic capacity of festulolium was significantly higher at 10...

  20. Environmental Compliance Assessment System (ECAS). Rhode Island Supplement

    Science.gov (United States)

    1994-07-01

    ft from the center line of Ashaway, Beaver, Blackstone , Chepechet, Clear, Falls, Flat, Hunt, Moshassuck., Moosup, Narrow, Pawcatuck, Pascoag...municipal recycling regulations, the Rhode Island Battery Deposit and Control Regulations, or oil subject to the hard-to- dispose-of tax . " Recyclable...designed to backfire into the feed hopper. avoid backfire into the feed hopper (RIDEM Verify that the feed hopper is designed to allow removal of refuse

  1. Influence of insemination time on fertility of Rhodes island white ...

    African Journals Online (AJOL)

    Influence of insemination time on fertility of Rhodes island white chicken (Gallus domestica) raised in northern guinea savannah zone of Nigeria. D Zahraddeen, ISR Butswat, KM Bello, AA Washik. Abstract. No Abstract. International Journal of Tropical Agriculture and Food Systems Vol. 1 (4) 2007: pp. 378-383. Full Text:.

  2. Rhode Island, Connecticut, New York, and New Jersey ESI: INVERTPT (Invertebrate Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for rare terrestrial invertebrates in coastal Rhode Island, Connecticut, New York, and New Jersey. Vector...

  3. Broadband Wireline Provider Service: Other Copper Wireline; BBRI_otherCopper12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via "Other Copper Wireline" technology. In Rhode Island, this category...

  4. Photosynthesis research in the USSR

    Energy Technology Data Exchange (ETDEWEB)

    Hall, D.O.

    1979-09-27

    Current research programs in photosynthesis in the USSR are described. Some of the programs include: (1) research on hydrogenases; (2) computer facilities (3) photochemical reduction of low potential compounds; (4) hydrogen-producing systems using model pigment systems; (5) stabilization of chloroplast membranes; (6) construction of fuel cells using immobilized enzymes; (7) carbon, hydrogen, and nitrogen metabolism of photosynthetic bacteria; (8) methane producing bacteria; (9) growth of photosynthetic bacteria under dark and light conditions; (10) efficiency of photosynthesis and plant productivity; (11) biomass as a future source of energy; (12) mycology; (13) isolation of photosystems; and (14) factors limiting photosynthesis in the leaf. (DC)

  5. Numerical simulation of the 2002 Northern Rhodes Slide (Greece) and evaluation of the generated tsunami

    Science.gov (United States)

    Zaniboni, Filippo; Armigliato, Alberto; Pagnoni, Gianluca; Tinti, Stefano

    2013-04-01

    Small landslides are very common along the submarine margins, due to steep slopes and continuous material deposition that increment mass instability and supply collapse occurrences, even without earthquake triggering. This kind of events can have relevant consequences when occurring close to the coast, because they are characterized by sudden change of velocity and relevant speed achievement, reflecting into high tsunamigenic potential. This is the case for example of the slide of Rhodes Island (Greece), named Northern Rhodes Slide (NRS), where unusual 3-4 m waves were registered on 24 March 2002, provoking some damage in the coastal stretch of the city of Rhodes (Papadopoulos et al., 2007). The event was not associated with earthquake occurrence, and eyewitnesses supported the hypothesis of a non-seismic source for the tsunami, placed 1 km offshore. Subsequent marine geophysical surveys (Sakellariou et al., 2002) evidenced the presence of several detachment niches at about 300-400 m depth along the northern steep slope, one of which can be considered responsible of the observed tsunami, fitting with the previously mentioned supposition. In this work, that is carried out in the frame of the European funded project NearToWarn, we evaluated the tsunami effects due to the NRS by means of numerical modelling: after having reconstructed the sliding body basing on morphological assumptions (obtaining an esteemed volume of 33 million m3), we simulated the sliding motion through the in-house built code UBO-BLOCK1, adopting a Lagrangian approach and splitting the sliding mass into a "chain" of interacting blocks. This provides the complete dynamics of the landslide, including the shape changes that relevantly influence the tsunami generation. After the application of an intermediate code, accounting for the slide impulse filtering through the water depth, the tsunami propagation in the sea around the island of Rhodes and up to near coasts of Turkey was simulated via the

  6. Rhode Island, Connecticut, New York, and New Jersey ESI: FISH (Fish Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and anadromous fish species in coastal Rhode Island, Connecticut, New York, and New...

  7. "It's been a long road to acceptance": midwives in Rhode Island, 1970-2000.

    Science.gov (United States)

    Caron, Simone M

    2014-01-01

    A resurgence of midwifery came to Rhode Island in the 1970s. Midwives acted as modern health care professionals to conserve a traditional woman-centered birth, but the battle was long and arduous, from Dr. Ellen Stone attempting to eliminate midwives in the state in 1912 to doctors using the death of 2 home birth infants in the 1980s to undermine the growing presence of professional nurse-midwives in the state. Midwives prevailed when the state legislature passed measures in 1988 and 1990 increasing the power and authority of midwives, and when a federal grant in 1993 allowed the University of Rhode Island to open the first training program for nurse-midwives in the state.

  8. "Into Your Hands His Life and Liberty...." A Collection of Significant Cases from the Rhode Island Courts. First Edition.

    Science.gov (United States)

    Leonard, Donald E.; Mattson, John O., Ed.

    Six cases from Rhode Island court history are presented in this document. The cases, dating from the time of Roger Williams to the 1970s, examine religious freedom, personal freedom, treason, robbery, murder, and drug possession. Each case is summarized and questions are supplied to help students understand crime and punishment in Rhode Island. A…

  9. Digital Learning Compass: Distance Education State Almanac 2017. Rhode Island

    Science.gov (United States)

    Seaman, Julia E.; Seaman, Jeff

    2017-01-01

    This brief report uses data collected under the U.S. Department of Education's National Center for Educational Statistics (NCES) Integrated Postsecondary Education Data System (IPEDS) Fall Enrollment survey to highlight distance education data in the state of Rhode Island. The sample for this analysis is comprised of all active, degree-granting…

  10. Physiological and Environmental Aspects of Photosynthesis

    OpenAIRE

    Ricardo Alfredo Kluge; Universidade de São Paulo; Jaqueline V. Tezotto-Uliana; Universidade de São Paulo; Paula P. M. da Silva; Universidade de São Paulo

    2015-01-01

    Undoubtedly, photosynthesis is one of the most important process for the life planet maintenance. The sun releases radiant energy that is able to boost the photosynthetic apparatus of the plants, which produce carbohydrates that will be used in the respiration. Among the most important reactions of photosynthesis is the release of oxygen, essential for respiration, which happens in photosystem II. The products generated in the first phase of photosynthesis or photochemical phase (ATP and NADP...

  11. Retrospective analysis of heavy metal contamination in Rhode Island based on old and new herbarium specimens.

    Science.gov (United States)

    Rudin, Sofia M; Murray, David W; Whitfeld, Timothy J S

    2017-01-01

    Herbarium specimens may provide a record of past environmental conditions, including heavy metal pollution. To explore this potential, we compared concentrations of copper, lead, and zinc in historical and new collections from four sites in Rhode Island, USA. We compared historical specimens (1846 to 1916) to congener specimens collected in 2015 at three former industrial sites in Providence, Rhode Island, and one nonindustrial site on Block Island. Leaf material was prepared by UltraWAVE SRC Microwave Digestion, and heavy metal concentrations were measured by inductively coupled plasma-atomic emission spectroscopy. Heavy metal concentrations in the historical and new specimens were measurable for all elements tested, and levels of copper and zinc were comparable in the historical and 2015 collections. By contrast, the concentration of lead declined at all sites over time. Significant variability in heavy metal concentration was observed between taxa, reflecting their varied potential for elemental accumulation. It seems clear that herbarium specimens can be used to evaluate past levels of pollution and assess local environmental changes. With careful sampling effort, these specimens can be a valuable part of environmental science research. Broadening the possible applications for herbarium collections in this way increases their relevance in an era of reduced funding for collections-based research.

  12. 2012 USACE Post Sandy Topographic LiDAR: Rhode Island and Massachusetts Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This topographic elevation point data derived from multiple return light detection and ranging (LiDAR) represents 354.272 square miles of coastline for Rhode Island...

  13. Rhode Island, Connecticut, New York, and New Jersey ESI: FISHL (Fish Lines)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for anadromous fish species in coastal Rhode Island, Connecticut, New York, and New Jersey. Vector arcs in...

  14. Rhode Island, Connecticut, New York, and New Jersey ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting birds in coastal Rhode Island, Connecticut, New York, and New Jersey. Vector points in this...

  15. Providence Sponsors Diocesan Teacher Recruiting Campaign.

    Science.gov (United States)

    Dygert, William

    2001-01-01

    Addresses the issue of teacher recruitment in Providence, Rhode Island. Explains that the Catholic education staff designed a campaign that involved creating marketing materials, advertising in daily newspapers, and holding job fairs and open houses. Stresses the importance of promoting teaching at Catholic schools as both rewarding and…

  16. CTD data from Rhode Island Sound collected from R/V Hope Hudner in 2009-2010 in support of Rhode Island Ocean Special Area Management Plan (NODC Accession 0109929)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset consists of 173 CTD casts in Rhode Island and Block Island Sounds obtained during 4 surveys. The surveys were performed during 22-24 September 2009, 7-8...

  17. Semen bacterial flora of Rhode Island Breeder cocks in Zaria ...

    African Journals Online (AJOL)

    The semen used in this study was collected from 77 Rhode Island Breeder cocks reared in battery cages under intensive management from a private farm in Zaria, Kaduna State, Nigeria using the back massage procedure, 27 of the 77 semen samples (35.1%) contained bacterial isolates. None of the samples grew fungi.

  18. Microclimate, canopy structure and photosynthesis in canopies of three contrasting temperate forage grasses. III. Canopy photosynthesis, individual leaf photosynthesis and the distribution of current assimilate

    Energy Technology Data Exchange (ETDEWEB)

    Sheehy, J E

    1977-01-01

    The rates of canopy and individual leaf photosynthesis and /sup 14/C distribution for three temperate forage grasses Lolium perenne cv. S24, L. perenne cv. Reveille and Festuca arundinacea cv. S170 were determined in the field during a summer growth period. Canopy photosynthesis declined as the growth period progressed, reflecting a decline in the photosynthetic capacity of successive youngest fully expanded leaves. The decline in the maximum photosynthetic capacity of the canopies was correlated with a decline in their quantum efficiencies at low irradiance. Changes in canopy structure resulted in changes in canopy net photosynthesis and dark respiration. No clear relationships between changes in the environment and changes in canopy net photosynthesis and dark respiration were established. The relative distributions of /sup 14/C in the shoots of the varieties gave a good indication of the amount of dry matter per ground area in the varieties. 21 references, 4 figures, 1 table.

  19. Hydrogeologic data for the Big River-Mishnock River stream-aquifer system, central Rhode Island

    Science.gov (United States)

    Craft, P.A.

    2001-01-01

    Hydrogeology, ground-water development alternatives, and water quality in the BigMishnock stream-aquifer system in central Rhode Island are being investigated as part of a long-term cooperative program between the Rhode Island Water Resources Board and the U.S. Geological Survey to evaluate the ground-water resources throughout Rhode Island. The study area includes the Big River drainage basin and that portion of the Mishnock River drainage basin upstream from the Mishnock River at State Route 3. This report presents geologic data and hydrologic and water-quality data for ground and surface water. Ground-water data were collected from July 1996 through September 1998 from a network of observation wells consisting of existing wells and wells installed for this study, which provided a broad distribution of data-collection sites throughout the study area. Streambed piezometers were used to obtain differences in head data between surface-water levels and ground-water levels to help evaluate stream-aquifer interactions throughout the study area. The types of data presented include monthly ground-water levels, average daily ground-water withdrawals, drawdown data from aquifer tests, and water-quality data. Historical water-level data from other wells within the study area also are presented in this report. Surface-water data were obtained from a network consisting of surface-water impoundments, such as ponds and reservoirs, existing and newly established partial-record stream-discharge sites, and synoptic surface-water-quality sites. Water levels were collected monthly from the surface-water impoundments. Stream-discharge measurements were made at partial-record sites to provide measurements of inflow, outflow, and internal flow throughout the study area. Specific conductance was measured monthly at partial-record sites during the study, and also during the fall and spring of 1997 and 1998 at 41 synoptic sites throughout the study area. General geologic data, such as

  20. Potential photosynthesis of crop surfaces.

    NARCIS (Netherlands)

    Wit, de C.T.

    1959-01-01

    A formula for calculating the potential photosynthesis of a closed crop surface is proposed, assuming that the leaves of the crop are not arranged in any definite direction. In the Netherlands, values for potential photosynthesis vary from 290 kg. CH2O/ha./day in June to 50 kg./ha./day in December.

  1. Leaf absorbance and photosynthesis

    Science.gov (United States)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  2. Measurement of solar spectra relating to photosynthesis and solar cells: an inquiry lab for secondary science.

    Science.gov (United States)

    Ruggirello, Rachel M; Balcerzak, Phyllis; May, Victoria L; Blankenship, Robert E

    2012-07-01

    The process of photosynthesis is central to science curriculum at all levels. This article describes an inquiry-based laboratory investigation developed to explore the impact of light quality on photosynthesis and to connect this process to current research on harvesting solar energy, including bioenergy, artificial photosynthesis, and solar cells. This laboratory was used with high-school science teachers who then took this experience back to their classrooms. During this exercise, teachers used an economical spectroradiometer to measure the solar spectrum and relate this to photosynthetic light absorption by determining the quality of light beneath trees. Following this investigation, teachers learned about the plant-inspired dye-sensitized solar cells and constructed one. To connect their light quality investigation to the efficiency of photosynthesis and solar cells, teachers then collected data at locations with varying quality and intensity of light. In sum, this investigation provides a crucial connection between photosynthesis and cutting edge research on solar energy technologies. Our learning experience provides a new instructional model for understanding a little investigated aspect of photosynthesis and connects to authentic scientific research. Copyright © 2012 Wiley Periodicals, Inc.

  3. Could photosynthesis function on Proxima Centauri b?

    Science.gov (United States)

    Ritchie, Raymond J.; Larkum, Anthony W. D.; Ribas, Ignasi

    2018-04-01

    Could oxygenic and/or anoxygenic photosynthesis exist on planet Proxima Centauri b? Proxima Centauri (spectral type - M5.5 V, 3050 K) is a red dwarf, whereas the Sun is type G2 V (5780 K). The light regimes on Earth and Proxima Centauri b are compared with estimates of the planet's suitability for Chlorophyll a (Chl a) and Chl d-based oxygenic photosynthesis and for bacteriochlorophyll (BChl)-based anoxygenic photosynthesis. Proxima Centauri b has low irradiance in the oxygenic photosynthesis range (400-749 nm: 64-132 µmol quanta m-2 s-1). Much larger amounts of light would be available for BChl-based anoxygenic photosynthesis (350-1100 nm: 724-1538 µmol quanta m-2 s-1). We estimated primary production under these light regimes. We used the oxygenic algae Synechocystis PCC6803, Prochlorothrix hollandica, Acaryochloris marina, Chlorella vulgaris, Rhodomonas sp. and Phaeodactylum tricornutum and the anoxygenic photosynthetic bacteria Rhodopseudomonas palustris (BChl a), Afifella marina (BChl a), Thermochromatium tepidum (BChl a), Chlorobaculum tepidum (BChl a + c) and Blastochloris viridis (BChl b) as representative photosynthetic organisms. Proxima Centauri b has only ~3% of the PAR (400-700 nm) of Earth irradiance, but we found that potential gross photosynthesis (P g) on Proxima Centauri b could be surprisingly high (oxygenic photosynthesis: earth ~0.8 gC m-2 h-1 Proxima Centauri b ~0.14 gC m-2 h-1). The proportion of PAR irradiance useable by oxygenic photosynthetic organisms (the sum of Blue + Red irradiance) is similar for the Earth and Proxima Centauri b. The oxygenic photic zone would be only ~10 m deep in water compared with ~200 m on Earth. The P g of an anoxic Earth (gC m-2 h-1) is ~0.34-0.59 (land) and could be as high as ~0.29-0.44 on Proxima Centauri b. 1 m of water does not affect oxygenic or anoxygenic photosynthesis on Earth, but on Proxima Centauri b oxygenic P g is reduced by ~50%. Effective elimination of near IR limits P g by photosynthetic

  4. The History of the Rhodes State College Dental Hygiene Program

    Science.gov (United States)

    Bowers, Denise E.

    2012-01-01

    The historiography of the Rhodes State College Dental Hygiene Program (Program) presents a historical journey of health care, as it relates to oral health, in the United States, in Ohio, and in Lima. This study bridges the gap between the history of higher education and the history of an academic program, dental hygiene. Prior to this study, there…

  5. Estimating phytoplankton photosynthesis by active fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Falkowski, P.G.; Kolber, Z.

    1992-01-01

    Photosynthesis can be described by target theory, At low photon flux densities, photosynthesis is a linear function of irradiance (I), The number of reaction centers (n), their effective absorption capture cross section {sigma}, and a quantum yield {phi}. As photosynthesis becomes increasingly light saturated, an increased fraction of reaction centers close. At light saturation the maximum photosynthetic rate is given as the product of the number of reaction centers (n) and their maximum electron transport rate (I/{tau}). Using active fluorometry it is possible to measure non-destructively and in real time the fraction of open or closed reaction centers under ambient irradiance conditions in situ, as well as {sigma} and {phi} {tau} can be readily, calculated from knowledge of the light saturation parameter, I{sub k} (which can be deduced by in situ by active fluorescence measurements) and {sigma}. We built a pump and probe fluorometer, which is interfaced with a CTD. The instrument measures the fluorescence yield of a weak probe flash preceding (f{sub 0}) and succeeding (f{sub 0}) a saturating pump flash. Profiles of the these fluorescence yields are used to derive the instantaneous rate of gross photosynthesis in natural phytoplankton communities without any incubation. Correlations with short-term simulated in situ radiocarbon measurements are extremely high. The average slope between photosynthesis derived from fluorescence and that measured by radiocarbon is 1.15 and corresponds to the average photosynthetic quotient. The intercept is about 15% of the maximum radiocarbon uptake and corresponds to the average net community respiration. Profiles of photosynthesis and sections showing the variability in its composite parameters reveal a significant effect of nutrient availability on biomass specific rates of photosynthesis in the ocean.

  6. Estimating phytoplankton photosynthesis by active fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Falkowski, P.G.; Kolber, Z.

    1992-10-01

    Photosynthesis can be described by target theory, At low photon flux densities, photosynthesis is a linear function of irradiance (I), The number of reaction centers (n), their effective absorption capture cross section {sigma}, and a quantum yield {phi}. As photosynthesis becomes increasingly light saturated, an increased fraction of reaction centers close. At light saturation the maximum photosynthetic rate is given as the product of the number of reaction centers (n) and their maximum electron transport rate (I/{tau}). Using active fluorometry it is possible to measure non-destructively and in real time the fraction of open or closed reaction centers under ambient irradiance conditions in situ, as well as {sigma} and {phi} {tau} can be readily, calculated from knowledge of the light saturation parameter, I{sub k} (which can be deduced by in situ by active fluorescence measurements) and {sigma}. We built a pump and probe fluorometer, which is interfaced with a CTD. The instrument measures the fluorescence yield of a weak probe flash preceding (f{sub 0}) and succeeding (f{sub 0}) a saturating pump flash. Profiles of the these fluorescence yields are used to derive the instantaneous rate of gross photosynthesis in natural phytoplankton communities without any incubation. Correlations with short-term simulated in situ radiocarbon measurements are extremely high. The average slope between photosynthesis derived from fluorescence and that measured by radiocarbon is 1.15 and corresponds to the average photosynthetic quotient. The intercept is about 15% of the maximum radiocarbon uptake and corresponds to the average net community respiration. Profiles of photosynthesis and sections showing the variability in its composite parameters reveal a significant effect of nutrient availability on biomass specific rates of photosynthesis in the ocean.

  7. Retrospective analysis of heavy metal contamination in Rhode Island based on old and new herbarium specimens1

    Science.gov (United States)

    Rudin, Sofia M.; Murray, David W.; Whitfeld, Timothy J. S.

    2017-01-01

    Premise of the study: Herbarium specimens may provide a record of past environmental conditions, including heavy metal pollution. To explore this potential, we compared concentrations of copper, lead, and zinc in historical and new collections from four sites in Rhode Island, USA. Methods: We compared historical specimens (1846 to 1916) to congener specimens collected in 2015 at three former industrial sites in Providence, Rhode Island, and one nonindustrial site on Block Island. Leaf material was prepared by UltraWAVE SRC Microwave Digestion, and heavy metal concentrations were measured by inductively coupled plasma–atomic emission spectroscopy. Results: Heavy metal concentrations in the historical and new specimens were measurable for all elements tested, and levels of copper and zinc were comparable in the historical and 2015 collections. By contrast, the concentration of lead declined at all sites over time. Significant variability in heavy metal concentration was observed between taxa, reflecting their varied potential for elemental accumulation. Discussion: It seems clear that herbarium specimens can be used to evaluate past levels of pollution and assess local environmental changes. With careful sampling effort, these specimens can be a valuable part of environmental science research. Broadening the possible applications for herbarium collections in this way increases their relevance in an era of reduced funding for collections-based research. PMID:28090410

  8. Phytotoxicity of chiral herbicide bromacil: Enantioselectivity of photosynthesis in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zunwei; Zou, Yuqin; Wang, Jia [MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Li, Meichao [Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032 (China); Wen, Yuezhong, E-mail: wenyuezhong@zju.edu.cn [MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

    2016-04-01

    With the wide application of chiral herbicides and the frequent detection of photosystem II (PSII) herbicides, it is of great importance to assess the direct effects of PSII herbicides on photosynthesis in an enantiomeric level. In the present study, the enantioselective phytotoxicity of bromacil (BRO), typical photosynthesis inhibition herbicide, on Arabidopsis thaliana was investigated. The results showed that S-BRO exhibited a greater inhibition of electron transmission in photosystem I (PSI) of A. thaliana than R-BRO by inhibiting the transcription of fnr 1. S-BRO also changed the chlorophyll fluorescence parameters Y (II), Y (NO), and Y (NPQ) to a greater extent than R-Bro. Transcription of genes psbO2, Lhcb3 and Lhcb6 was down-regulated in an enantioselective rhythm and S-BRO caused more serious influence, indicating that S-BRO did worse damage to the photosystem II (PSII) of A. thaliana than R-BRO. This study suggested that S-BRO disturbed the photosynthesis of plants to a larger extent than R-BRO and provided a new sight to evaluate the phytotoxicity of chiral herbicides. - Highlights: • It is necessary to assess the direct effects of PSII herbicides on photosynthesis. • Phytotoxicity of bromacil is investigated in an enantiomeric level. • Bromacil disturbed enantioselectively the photosystem II of Arabidopsis thaliana. • S-bromacil caused severer damage to photosynthesis of Arabidopsis than R-bromacil. • Photosynthesis should be considered for phytotoxicity assessment of herbicides.

  9. Phytotoxicity of chiral herbicide bromacil: Enantioselectivity of photosynthesis in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Chen, Zunwei; Zou, Yuqin; Wang, Jia; Li, Meichao; Wen, Yuezhong

    2016-01-01

    With the wide application of chiral herbicides and the frequent detection of photosystem II (PSII) herbicides, it is of great importance to assess the direct effects of PSII herbicides on photosynthesis in an enantiomeric level. In the present study, the enantioselective phytotoxicity of bromacil (BRO), typical photosynthesis inhibition herbicide, on Arabidopsis thaliana was investigated. The results showed that S-BRO exhibited a greater inhibition of electron transmission in photosystem I (PSI) of A. thaliana than R-BRO by inhibiting the transcription of fnr 1. S-BRO also changed the chlorophyll fluorescence parameters Y (II), Y (NO), and Y (NPQ) to a greater extent than R-Bro. Transcription of genes psbO2, Lhcb3 and Lhcb6 was down-regulated in an enantioselective rhythm and S-BRO caused more serious influence, indicating that S-BRO did worse damage to the photosystem II (PSII) of A. thaliana than R-BRO. This study suggested that S-BRO disturbed the photosynthesis of plants to a larger extent than R-BRO and provided a new sight to evaluate the phytotoxicity of chiral herbicides. - Highlights: • It is necessary to assess the direct effects of PSII herbicides on photosynthesis. • Phytotoxicity of bromacil is investigated in an enantiomeric level. • Bromacil disturbed enantioselectively the photosystem II of Arabidopsis thaliana. • S-bromacil caused severer damage to photosynthesis of Arabidopsis than R-bromacil. • Photosynthesis should be considered for phytotoxicity assessment of herbicides.

  10. Photosynthesis Activates Plasma Membrane H+-ATPase via Sugar Accumulation.

    Science.gov (United States)

    Okumura, Masaki; Inoue, Shin-Ichiro; Kuwata, Keiko; Kinoshita, Toshinori

    2016-05-01

    Plant plasma membrane H(+)-ATPase acts as a primary transporter via proton pumping and regulates diverse physiological responses by controlling secondary solute transport, pH homeostasis, and membrane potential. Phosphorylation of the penultimate threonine and the subsequent binding of 14-3-3 proteins in the carboxyl terminus of the enzyme are required for H(+)-ATPase activation. We showed previously that photosynthesis induces phosphorylation of the penultimate threonine in the nonvascular bryophyte Marchantia polymorpha However, (1) whether this response is conserved in vascular plants and (2) the process by which photosynthesis regulates H(+)-ATPase phosphorylation at the plasma membrane remain unresolved issues. Here, we report that photosynthesis induced the phosphorylation and activation of H(+)-ATPase in Arabidopsis (Arabidopsis thaliana) leaves via sugar accumulation. Light reversibly phosphorylated leaf H(+)-ATPase, and this process was inhibited by pharmacological and genetic suppression of photosynthesis. Immunohistochemical and biochemical analyses indicated that light-induced phosphorylation of H(+)-ATPase occurred autonomously in mesophyll cells. We also show that the phosphorylation status of H(+)-ATPase and photosynthetic sugar accumulation in leaves were positively correlated and that sugar treatment promoted phosphorylation. Furthermore, light-induced phosphorylation of H(+)-ATPase was strongly suppressed in a double mutant defective in ADP-glucose pyrophosphorylase and triose phosphate/phosphate translocator (adg1-1 tpt-2); these mutations strongly inhibited endogenous sugar accumulation. Overall, we show that photosynthesis activated H(+)-ATPase via sugar production in the mesophyll cells of vascular plants. Our work provides new insight into signaling from chloroplasts to the plasma membrane ion transport mechanism. © 2016 American Society of Plant Biologists. All Rights Reserved.

  11. What is the most prominent factor limiting photosynthesis in different layers of a greenhouse cucumber canopy?

    Science.gov (United States)

    Chen, Tsu-Wei; Henke, Michael; de Visser, Pieter H B; Buck-Sorlin, Gerhard; Wiechers, Dirk; Kahlen, Katrin; Stützel, Hartmut

    2014-09-01

    Maximizing photosynthesis at the canopy level is important for enhancing crop yield, and this requires insights into the limiting factors of photosynthesis. Using greenhouse cucumber (Cucumis sativus) as an example, this study provides a novel approach to quantify different components of photosynthetic limitations at the leaf level and to upscale these limitations to different canopy layers and the whole plant. A static virtual three-dimensional canopy structure was constructed using digitized plant data in GroIMP. Light interception of the leaves was simulated by a ray-tracer and used to compute leaf photosynthesis. Different components of photosynthetic limitations, namely stomatal (S(L)), mesophyll (M(L)), biochemical (B(L)) and light (L(L)) limitations, were calculated by a quantitative limitation analysis of photosynthesis under different light regimes. In the virtual cucumber canopy, B(L) and L(L) were the most prominent factors limiting whole-plant photosynthesis. Diffusional limitations (S(L) + M(L)) contributed Photosynthesis in the lower canopy was more limited by the biochemical capacity, and the upper canopy was more sensitive to light than other canopy parts. Although leaves in the upper canopy received more light, their photosynthesis was more light restricted than in the leaves of the lower canopy, especially when the light condition above the canopy was poor. An increase in whole-plant photosynthesis under diffuse light did not result from an improvement of light use efficiency but from an increase in light interception. Diffuse light increased the photosynthesis of leaves that were directly shaded by other leaves in the canopy by up to 55%. Based on the results, maintaining biochemical capacity of the middle-lower canopy and increasing the leaf area of the upper canopy would be promising strategies to improve canopy photosynthesis in a high-wire cucumber cropping system. Further analyses using the approach described in this study can be expected to

  12. Circumstantial Evidence of Possible Hot Spot Activity Outside Rhodes, Eastern Mediterranean Sea

    OpenAIRE

    Miliaresis, George

    2014-01-01

    Zouzias Dimitrios, St Seymour Karen, Miliaresis George, Vamvoukakis Costas (2008). Circumstantial Evidence of Possible Hot Spot Activity Outside Rhodes, Eastern Mediterranean Sea. 3rd International Conference on the Geology of the Tethys (8-11 January, 2008, South Valley University - Aswan). [Abstract in Program

  13. Regulation of bacterial photosynthesis genes by the small noncoding RNA PcrZ.

    Science.gov (United States)

    Mank, Nils N; Berghoff, Bork A; Hermanns, Yannick N; Klug, Gabriele

    2012-10-02

    The small RNA PcrZ (photosynthesis control RNA Z) of the facultative phototrophic bacterium Rhodobacter sphaeroides is induced upon a drop of oxygen tension with similar kinetics to those of genes for components of photosynthetic complexes. High expression of PcrZ depends on PrrA, the response regulator of the PrrB/PrrA two-component system with a central role in redox regulation in R. sphaeroides. In addition the FnrL protein, an activator of some photosynthesis genes at low oxygen tension, is involved in redox-dependent expression of this small (s)RNA. Overexpression of full-length PcrZ in R. sphaeroides affects expression of a small subset of genes, most of them with a function in photosynthesis. Some mRNAs from the photosynthetic gene cluster were predicted to be putative PcrZ targets and results from an in vivo reporter system support these predictions. Our data reveal a negative effect of PcrZ on expression of its target mRNAs. Thus, PcrZ counteracts the redox-dependent induction of photosynthesis genes, which is mediated by protein regulators. Because PrrA directly activates photosynthesis genes and at the same time PcrZ, which negatively affects photosynthesis gene expression, this is one of the rare cases of an incoherent feed-forward loop including an sRNA. Our data identified PcrZ as a trans acting sRNA with a direct regulatory function in formation of photosynthetic complexes and provide a model for the control of photosynthesis gene expression by a regulatory network consisting of proteins and a small noncoding RNA.

  14. Rhode Island, Connecticut, New York, and New Jersey ESI: HABITATS (Habitat and Plant Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for eelgrass, macroalgae, submerged aquatic vegetation, and rare terrestrial plants in coastal Rhode...

  15. Consumer Behavior and Greenhouse Gas Emissions at the University of Rhode Island

    Science.gov (United States)

    2009-12-31

    Of the 16,000 students at the University of Rhode Island, about 55% percent commute to campus. Between students, staff and faculty there could be up to 11,000 commuters at the University, most of which drive alone. A high volume of single-occupancy v...

  16. 40 CFR 81.31 - Metropolitan Providence Interstate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ... Quality Control Region. 81.31 Section 81.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.31 Metropolitan Providence Interstate Air Quality Control Region. The Metropolitan Providence Interstate Air Quality Control Region (Rhode Island-Massachusetts) consists of the...

  17. Proteomic approaches in research of cyanobacterial photosynthesis.

    Science.gov (United States)

    Battchikova, Natalia; Angeleri, Martina; Aro, Eva-Mari

    2015-10-01

    Oxygenic photosynthesis in cyanobacteria, algae, and plants is carried out by a fabulous pigment-protein machinery that is amazingly complicated in structure and function. Many different approaches have been undertaken to characterize the most important aspects of photosynthesis, and proteomics has become the essential component in this research. Here we describe various methods which have been used in proteomic research of cyanobacteria, and demonstrate how proteomics is implemented into on-going studies of photosynthesis in cyanobacterial cells.

  18. Long-Term Ground-Water Levels and Transmissivity in the Blackstone River Basin, Northern Rhode Island

    Science.gov (United States)

    Eggleston, Jack R.; Church, Peter E.; Barbaro, Jeffrey R.

    2007-01-01

    Ground water provides about 7.7 million gallons per day, or 28 percent of total water use in the Rhode Island part of the Blackstone River Basin. Primary aquifers in the basin are stratified glacial deposits, composed mostly of sand and gravel along valley bottoms. The ground-water and surface-water system in the Blackstone River Basin is under stress due to population growth, out-of-basin water transfers, industrialization, and changing land-use patterns. Streamflow periodically drops below the Aquatic Base Flow standard, and ground-water withdrawals add to stress on aquatic habitat during low-flow periods. Existing hydrogeologic data were reviewed to examine historical water-level trends and to generate contour maps of water-table altitudes and transmissivity of the sand and gravel aquifer in the Blackstone River Basin in Rhode Island. On the basis of data from four long-term observation wells, water levels appear to have risen slightly in the study area during the past 55 years. Analysis of available data indicates that increased rainfall during the same period is a likely contributor to the water-level rise. Spatial patterns of transmissivity are shown over larger areas and have been refined on the basis of more detailed data coverage as compared to previous mapping studies.

  19. Rhode Island, Connecticut, New York, and New Jersey ESI: REPTILES (Reptile and Amphibian Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for threatened/endangered sea turtles, diamondback terrapins, and rare reptiles/amphibians in coastal Rhode...

  20. Evaluation of the impact of the 2012 Rhode Island health care worker influenza vaccination regulations: implementation process and vaccination coverage.

    Science.gov (United States)

    Kim, Hanna; Lindley, Megan C; Dube, Donna; Kalayil, Elizabeth J; Paiva, Kristi A; Raymond, Patricia

    2015-01-01

    In October 2012, the Rhode Island Department of Health (HEALTH) amended its health care worker (HCW) vaccination regulations to require all HCWs to receive annual influenza vaccination or wear a surgical mask during direct patient contact when influenza is widespread. Unvaccinated HCWs failing to wear a mask are subject to a fine and disciplinary action. To describe the implementation of the 2012 Rhode Island HCW influenza vaccination regulations and examine their impact on vaccination coverage. Two data sources were used: (1) a survey of all health care facilities subject to the HCW regulations and (2) HCW influenza vaccination coverage data reported to HEALTH by health care facilities. Descriptive statistics and paired t tests were performed using SAS Release 9.2. For the 2012-2013 influenza season, 271 inpatient and outpatient health care facilities in Rhode Island were subject to the HCW regulations. Increase in HCW influenza vaccination coverage. Of the 271 facilities, 117 facilities completed the survey (43.2%) and 160 facilities reported vaccination data to HEALTH (59.0%). Between the 2011-2012 and 2012-2013 influenza seasons, the proportion of facilities having a masking policy, as required by the revised regulations, increased from 9.4% to 94.0% (P employee HCWs in Rhode Island increased from 69.7% in the 2011-2012 influenza season to 87.2% in the 2012-2013 season. Rhode Island's experience demonstrates that statewide HCW influenza vaccination requirements incorporating mask wearing and moderate penalties for noncompliance can be effective in improving influenza vaccination coverage among HCWs.

  1. School District Regionalization in Rhode Island: Relationship with Spending and Achievement

    Science.gov (United States)

    Masterson, Jason R.

    2012-01-01

    In Rhode Island, unless costs for education are controlled, taxpayers could face increased property taxes, increased sales tax on goods and services, and tax increases to existing fees to raise revenue (NEEP, 2010). Reducing the number of school districts was cited as the number two solution by the New England Economic Partnership in 2010 to…

  2. Modelling C₃ photosynthesis from the chloroplast to the ecosystem.

    Science.gov (United States)

    Bernacchi, Carl J; Bagley, Justin E; Serbin, Shawn P; Ruiz-Vera, Ursula M; Rosenthal, David M; Vanloocke, Andy

    2013-09-01

    Globally, photosynthesis accounts for the largest flux of CO₂ from the atmosphere into ecosystems and is the driving process for terrestrial ecosystem function. The importance of accurate predictions of photosynthesis over a range of plant growth conditions led to the development of a C₃ photosynthesis model by Farquhar, von Caemmerer & Berry that has become increasingly important as society places greater pressures on vegetation. The photosynthesis model has played a major role in defining the path towards scientific understanding of photosynthetic carbon uptake and the role of photosynthesis on regulating the earth's climate and biogeochemical systems. In this review, we summarize the photosynthesis model, including its continued development and applications. We also review the implications these developments have on quantifying photosynthesis at a wide range of spatial and temporal scales, and discuss the model's role in determining photosynthetic responses to changes in environmental conditions. Finally, the review includes a discussion of the larger-scale modelling and remote-sensing applications that rely on the leaf photosynthesis model and are likely to open new scientific avenues to address the increasing challenges to plant productivity over the next century. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  3. The interactive systems framework applied to the strategic prevention framework: the Rhode Island experience.

    Science.gov (United States)

    Florin, Paul; Friend, Karen B; Buka, Stephen; Egan, Crystelle; Barovier, Linda; Amodei, Brenda

    2012-12-01

    The Interactive Systems Framework for Dissemination and Implementation (ISF) was introduced as a heuristic systems level model to help bridge the gap between research and practice (Wandersman et al., in Am J Commun Psychol 41:171-181, 2008). This model describes three interacting systems with distinct functions that (1) distill knowledge to develop innovations; (2) provide supportive training and technical assistance for dissemination to; (3) a prevention delivery system responsible for implementation in the field. The Strategic Prevention Framework (SPF) is a major prevention innovation launched by the Center for Substance Abuse Prevention (CSAP) of the Substance Abuse and Mental Health Services Administration (SAMHSA). The SPF offers a structured, sequential, data-driven approach that explicitly targets environmental conditions in the community and aims for change in substance use and problems at the population level. This paper describes how the ISF was applied to the challenges of implementing the SPF in 14 Rhode Island communities, with a focus on the development of a new Training and Technical Assistance Resources Center to support SPF efforts. More specifically, we (1) describe each of the three ISF interacting systems as they evolved in Rhode Island; (2) articulate the lines of communication between the three systems; and (3) examine selected evaluation data to understand relationships between training and technical assistance and SPF implementation and outcomes.

  4. What is the most prominent factor limiting photosynthesis in different layers of a greenhouse cucumber canopy?

    NARCIS (Netherlands)

    Chen, T.W.; Henke, M.; Visser, de P.H.B.; Buck-Sorlin, G.H.; Wiechers, D.; Kahlen, K.; Stützel, H.

    2014-01-01

    Background and Aims Maximizing photosynthesis at the canopy level is important for enhancing crop yield, and this requires insights into the limiting factors of photosynthesis. Using greenhouse cucumber (Cucumis sativus) as an example, this study provides a novel approach to quantify different

  5. Magnitude of flood flows for selected annual exceedance probabilities in Rhode Island through 2010

    Science.gov (United States)

    Zarriello, Phillip J.; Ahearn, Elizabeth A.; Levin, Sara B.

    2012-01-01

    Heavy persistent rains from late February through March 2010 caused severe widespread flooding in Rhode Island that set or nearly set record flows and water levels at many long-term streamgages in the State. In response, the U.S. Geological Survey, in partnership with the Federal Emergency Management Agency, conducted a study to update estimates of flood magnitudes at streamgages and regional equations for estimating flood flows at ungaged locations. This report provides information needed for flood plain management, transportation infrastructure design, flood insurance studies, and other purposes that can help minimize future flood damages and risks. The magnitudes of floods were determined from the annual peak flows at 43 streamgages in Rhode Island (20 sites), Connecticut (14 sites), and Massachusetts (9 sites) using the standard Bulletin 17B log-Pearson type III method and a modification of this method called the expected moments algorithm (EMA) for 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probability (AEP) floods. Annual-peak flows were analyzed for the period of record through the 2010 water year; however, records were extended at 23 streamgages using the maintenance of variance extension (MOVE) procedure to best represent the longest period possible for determining the generalized skew and flood magnitudes. Generalized least square regression equations were developed from the flood quantiles computed at 41 streamgages (2 streamgages in Rhode Island with reported flood quantiles were not used in the regional regression because of regulation or redundancy) and their respective basin characteristics to estimate magnitude of floods at ungaged sites. Of 55 basin characteristics evaluated as potential explanatory variables, 3 were statistically significant—drainage area, stream density, and basin storage. The pseudo-coefficient of determination (pseudo-R2) indicates these three explanatory variables explain 95 to 96 percent of the variance

  6. Water-quality trends in the Scituate reservoir drainage area, Rhode Island, 1983-2012

    Science.gov (United States)

    Smith, Kirk P.

    2015-01-01

    The Scituate Reservoir is the primary source of drinking water for more than 60 percent of the population of Rhode Island. Water-quality and streamflow data collected at 37 surface-water monitoring stations in the Scituate Reservoir drainage area, Rhode Island, from October 2001 through September 2012, water years (WYs) 2002-12, were analyzed to determine water-quality conditions and constituent loads in the drainage area. Trends in water quality, including physical properties and concentrations of constituents, were investigated for the same period and for a longer period from October 1982 through September 2012 (WYs 1983-2012). Water samples were collected and analyzed by the Providence Water Supply Board, the agency that manages the Scituate Reservoir. Streamflow data were collected by the U.S. Geological Survey. Median values and other summary statistics for pH, color, turbidity, alkalinity, chloride, nitrite, nitrate, total coliform bacteria, Escherichia coli (E. coli), and orthophosphate were calculated for WYs 2003-12 for all 37 monitoring stations. Instantaneous loads and yields (loads per unit area) of total coliform bacteria and E. coli, chloride, nitrite, nitrate, and orthophosphate were calculated for all sampling dates during WYs 2003-12 for 23 monitoring stations with streamflow data. Values of physical properties and concentrations of constituents were compared with State and Federal water-quality standards and guidelines and were related to streamflow, land-use characteristics, varying classes of timber operations, and impervious surface areas.

  7. Rhode Island, Connecticut, New York, and New Jersey ESI: M_MAMMAL (Marine Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seals, whales, and dolphins in coastal Rhode Island, Connecticut, and the New York/New Jersey...

  8. Social Vulnerability Index (SoVI) for Rhode Island based on 2000 Census Block Groups

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data depicts the social vulnerability of Rhode Island census block groups to environmental hazards. Data were culled primarily from the 2000 Decennial Census.

  9. Rhode Island, Connecticut, New York, and New Jersey ESI: HABPT (Habitat and Plant Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for rare terrestrial plants in coastal Rhode Island, Connecticut, New York, and New Jersey. Vector points...

  10. Rhode Island, Connecticut, New York, and New Jersey ESI: HYDRO (Hydrography Lines and Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Rhode Island,...

  11. Social and Intel lectual Trends at Rhodes in the Early Sixties and ...

    African Journals Online (AJOL)

    canberry

    When I arrived at Rhodes in 1962, the only graduates I had ever met were doctors .... expect me to fail at university, were aston ished at the end of my first year to find .... Irving was a socialist and a deter mined one, but his best friend was fellow.

  12. Measuring the Influences That Affect Technological Literacy in Rhode Island High Schools

    Science.gov (United States)

    Walach, Michael

    2015-01-01

    This study sampled the current state of technological literacy in Rhode Island high schools using a new instrument, the Technological Literacy Assessment, which was developed for this study. Gender inequalities in technological literacy were discovered, and possible causes and solutions are presented. This study suggests possible next steps for…

  13. Metabolic flux ratio analysis and cell staining suggest the existence of C4 photosynthesis in Phaeodactylum tricornutum.

    Science.gov (United States)

    Huang, A; Liu, L; Zhao, P; Yang, C; Wang, G C

    2016-03-01

    Mechanisms for carbon fixation via photosynthesis in the diatom Phaeodactylum tricornutum Bohlin were studied recently but there remains a long-standing debate concerning the occurrence of C4 photosynthesis in this species. A thorough investigation of carbon metabolism and the evidence for C4 photosynthesis based on organelle partitioning was needed. In this study, we identified the flux ratios between C3 and C4 compounds in P. tricornutum using (13)C-labelling metabolic flux ratio analysis, and stained cells with various cell-permeant fluorescent probes to investigate the likely organelle partitioning required for single-cell C4 photosynthesis. Metabolic flux ratio analysis indicated the C3/C4 exchange ratios were high. Cell staining indicated organelle partitioning required for single-cell C4 photosynthesis might exist in P. tricornutum. The results of (13)C-labelling metabolic flux ratio analysis and cell staining suggest single-cell C4 photosynthesis exists in P. tricornutum. This study provides insights into photosynthesis patterns of P. tricornutum and the evidence for C4 photosynthesis based on (13)C-labelling metabolic flux ratio analysis and organelle partitioning. © 2015 The Society for Applied Microbiology.

  14. Rhode Island, Connecticut, New York, and New Jersey ESI: T_MAMMAL (Terrestrial Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for small mammal species in coastal Rhode Island, Connecticut, New York, and New Jersey. Vector polygons in...

  15. Global Analysis of Photosynthesis Transcriptional Regulatory Networks

    Science.gov (United States)

    Imam, Saheed; Noguera, Daniel R.; Donohue, Timothy J.

    2014-01-01

    Photosynthesis is a crucial biological process that depends on the interplay of many components. This work analyzed the gene targets for 4 transcription factors: FnrL, PrrA, CrpK and MppG (RSP_2888), which are known or predicted to control photosynthesis in Rhodobacter sphaeroides. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) identified 52 operons under direct control of FnrL, illustrating its regulatory role in photosynthesis, iron homeostasis, nitrogen metabolism and regulation of sRNA synthesis. Using global gene expression analysis combined with ChIP-seq, we mapped the regulons of PrrA, CrpK and MppG. PrrA regulates ∼34 operons encoding mainly photosynthesis and electron transport functions, while CrpK, a previously uncharacterized Crp-family protein, regulates genes involved in photosynthesis and maintenance of iron homeostasis. Furthermore, CrpK and FnrL share similar DNA binding determinants, possibly explaining our observation of the ability of CrpK to partially compensate for the growth defects of a ΔFnrL mutant. We show that the Rrf2 family protein, MppG, plays an important role in photopigment biosynthesis, as part of an incoherent feed-forward loop with PrrA. Our results reveal a previously unrealized, high degree of combinatorial regulation of photosynthetic genes and significant cross-talk between their transcriptional regulators, while illustrating previously unidentified links between photosynthesis and the maintenance of iron homeostasis. PMID:25503406

  16. Global analysis of photosynthesis transcriptional regulatory networks.

    Directory of Open Access Journals (Sweden)

    Saheed Imam

    2014-12-01

    Full Text Available Photosynthesis is a crucial biological process that depends on the interplay of many components. This work analyzed the gene targets for 4 transcription factors: FnrL, PrrA, CrpK and MppG (RSP_2888, which are known or predicted to control photosynthesis in Rhodobacter sphaeroides. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq identified 52 operons under direct control of FnrL, illustrating its regulatory role in photosynthesis, iron homeostasis, nitrogen metabolism and regulation of sRNA synthesis. Using global gene expression analysis combined with ChIP-seq, we mapped the regulons of PrrA, CrpK and MppG. PrrA regulates ∼34 operons encoding mainly photosynthesis and electron transport functions, while CrpK, a previously uncharacterized Crp-family protein, regulates genes involved in photosynthesis and maintenance of iron homeostasis. Furthermore, CrpK and FnrL share similar DNA binding determinants, possibly explaining our observation of the ability of CrpK to partially compensate for the growth defects of a ΔFnrL mutant. We show that the Rrf2 family protein, MppG, plays an important role in photopigment biosynthesis, as part of an incoherent feed-forward loop with PrrA. Our results reveal a previously unrealized, high degree of combinatorial regulation of photosynthetic genes and significant cross-talk between their transcriptional regulators, while illustrating previously unidentified links between photosynthesis and the maintenance of iron homeostasis.

  17. Rhode Island, Connecticut, New York, and New Jersey ESI: M_MAMPT (Marine Mammal Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seal haul-out sites in coastal Rhode Island, Connecticut, New York, and New Jersey. Vector points in...

  18. Effects of high temperature on photosynthesis and related gene expression in poplar

    Science.gov (United States)

    2014-01-01

    Background High temperature, whether transitory or constant, causes physiological, biochemical and molecular changes that adversely affect tree growth and productivity by reducing photosynthesis. To elucidate the photosynthetic adaption response and examine the recovery capacity of trees under heat stress, we measured gas exchange, chlorophyll fluorescence, electron transport, water use efficiency, and reactive oxygen-producing enzyme activities in heat-stressed plants. Results We found that photosynthesis could completely recover after less than six hours of high temperature treatment, which might be a turning point in the photosynthetic response to heat stress. Genome-wide gene expression analysis at six hours of heat stress identified 29,896 differentially expressed genes (15,670 up-regulated and 14,226 down-regulated), including multiple classes of transcription factors. These interact with each other and regulate the expression of photosynthesis-related genes in response to heat stress, controlling carbon fixation and changes in stomatal conductance. Heat stress of more than twelve hours caused reduced electron transport, damaged photosystems, activated the glycolate pathway and caused H2O2 production; as a result, photosynthetic capacity did not recover completely. Conclusions This study provides a systematic physiological and global gene expression profile of the poplar photosynthetic response to heat stress and identifies the main limitations and threshold of photosynthesis under heat stress. It will expand our understanding of plant thermostability and provides a robust dataset for future studies. PMID:24774695

  19. Association genetics and transcriptome analysis reveal a gibberellin-responsive pathway involved in regulating photosynthesis.

    Science.gov (United States)

    Xie, Jianbo; Tian, Jiaxing; Du, Qingzhang; Chen, Jinhui; Li, Ying; Yang, Xiaohui; Li, Bailian; Zhang, Deqiang

    2016-05-01

    Gibberellins (GAs) regulate a wide range of important processes in plant growth and development, including photosynthesis. However, the mechanism by which GAs regulate photosynthesis remains to be understood. Here, we used multi-gene association to investigate the effect of genes in the GA-responsive pathway, as constructed by RNA sequencing, on photosynthesis, growth, and wood property traits, in a population of 435 Populus tomentosa By analyzing changes in the transcriptome following GA treatment, we identified many key photosynthetic genes, in agreement with the observed increase in measurements of photosynthesis. Regulatory motif enrichment analysis revealed that 37 differentially expressed genes related to photosynthesis shared two essential GA-related cis-regulatory elements, the GA response element and the pyrimidine box. Thus, we constructed a GA-responsive pathway consisting of 47 genes involved in regulating photosynthesis, including GID1, RGA, GID2, MYBGa, and 37 photosynthetic differentially expressed genes. Single nucleotide polymorphism (SNP)-based association analysis showed that 142 SNPs, representing 40 candidate genes in this pathway, were significantly associated with photosynthesis, growth, and wood property traits. Epistasis analysis uncovered interactions between 310 SNP-SNP pairs from 37 genes in this pathway, revealing possible genetic interactions. Moreover, a structural gene-gene matrix based on a time-course of transcript abundances provided a better understanding of the multi-gene pathway affecting photosynthesis. The results imply a functional role for these genes in mediating photosynthesis, growth, and wood properties, demonstrating the potential of combining transcriptome-based regulatory pathway construction and genetic association approaches to detect the complex genetic networks underlying quantitative traits. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights

  20. Broadband Wireline Provider Service: Asymmetric xDSL; BBRI_DSLasym12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via Asymmetric xDSL technology. Broadband availability is summarized...

  1. Reintroducing Photosynthesis

    Science.gov (United States)

    Vila, F.; Sanz, A.

    2012-01-01

    This article reports on conceptual difficulties related to photosynthesis and respiratory metabolism of a Plant Physiology course for undergraduate students that could hinder their better learning of metabolic processes. A survey of results obtained in this area during the last 10 academic years was performed, as well as a specific test, aimed to…

  2. A natural variant of NAL1, selected in high-yield rice breeding programs, pleiotropically increases photosynthesis rate

    Science.gov (United States)

    Takai, Toshiyuki; Adachi, Shunsuke; Taguchi-Shiobara, Fumio; Sanoh-Arai, Yumiko; Iwasawa, Norio; Yoshinaga, Satoshi; Hirose, Sakiko; Taniguchi, Yojiro; Yamanouchi, Utako; Wu, Jianzhong; Matsumoto, Takashi; Sugimoto, Kazuhiko; Kondo, Katsuhiko; Ikka, Takashi; Ando, Tsuyu; Kono, Izumi; Ito, Sachie; Shomura, Ayahiko; Ookawa, Taiichiro; Hirasawa, Tadashi; Yano, Masahiro; Kondo, Motohiko; Yamamoto, Toshio

    2013-01-01

    Improvement of leaf photosynthesis is an important strategy for greater crop productivity. Here we show that the quantitative trait locus GPS (GREEN FOR PHOTOSYNTHESIS) in rice (Oryza sativa L.) controls photosynthesis rate by regulating carboxylation efficiency. Map-based cloning revealed that GPS is identical to NAL1 (NARROW LEAF1), a gene previously reported to control lateral leaf growth. The high-photosynthesis allele of GPS was found to be a partial loss-of-function allele of NAL1. This allele increased mesophyll cell number between vascular bundles, which led to thickened leaves, and it pleiotropically enhanced photosynthesis rate without the detrimental side effects observed in previously identified nal1 mutants, such as dwarf plant stature. Furthermore, pedigree analysis suggested that rice breeders have repeatedly selected the high-photosynthesis allele in high-yield breeding programs. The identification and utilization of NAL1 (GPS) can enhance future high-yield breeding and provides a new strategy for increasing rice productivity. PMID:23985993

  3. Broadband Wireline Provider Service: Symmetric xDSL; BBRI_DSLsym12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via Symmetric xDSL technology. Broadband availability is summarized at...

  4. Occurrence of the lessepsian species Portunus pelagicus (Crustacea and Apogon pharaonis (Pisces in the marine area of Rhodes Island

    Directory of Open Access Journals (Sweden)

    M. CORSINI-FOKA

    2004-06-01

    Full Text Available A large number of Red Sea species are colonizing the eastern Mediterranean Sea via the Suez Canal, mainly following the Anatolian coasts and spreading westwards. Portunus pelagicus is one of the most common Red Sea swimming crabs, first recorded in the Levantine Basin in 1898. Four specimens of P. pelagicus were collected in different marine areas of Rhodes Island from 1991 to 2000, while three specimens of the lessepsian fish Apogon pharaonis, first recorded in the Mediterranean in 1947, were caught during 2002 in the NW coast of Rhodes. The sub-tropical character of the marine area around Rhodes seems to facilitate the propagation of lessepsian species. These migrants have reached the island at different velocity and degree of establishment of their populations. The occurrence of the blue swimmer crab P. pelagicus and of the bullseye cardinal fish A. pharaonis increases the number of the decapod Crustacea and fish species of Red Sea origin observed in Greek waters.

  5. Seasonality of temperate forest photosynthesis and daytime respiration.

    Science.gov (United States)

    Wehr, R; Munger, J W; McManus, J B; Nelson, D D; Zahniser, M S; Davidson, E A; Wofsy, S C; Saleska, S R

    2016-06-30

    Terrestrial ecosystems currently offset one-quarter of anthropogenic carbon dioxide (CO2) emissions because of a slight imbalance between global terrestrial photosynthesis and respiration. Understanding what controls these two biological fluxes is therefore crucial to predicting climate change. Yet there is no way of directly measuring the photosynthesis or daytime respiration of a whole ecosystem of interacting organisms; instead, these fluxes are generally inferred from measurements of net ecosystem-atmosphere CO2 exchange (NEE), in a way that is based on assumed ecosystem-scale responses to the environment. The consequent view of temperate deciduous forests (an important CO2 sink) is that, first, ecosystem respiration is greater during the day than at night; and second, ecosystem photosynthetic light-use efficiency peaks after leaf expansion in spring and then declines, presumably because of leaf ageing or water stress. This view has underlain the development of terrestrial biosphere models used in climate prediction and of remote sensing indices of global biosphere productivity. Here, we use new isotopic instrumentation to determine ecosystem photosynthesis and daytime respiration in a temperate deciduous forest over a three-year period. We find that ecosystem respiration is lower during the day than at night-the first robust evidence of the inhibition of leaf respiration by light at the ecosystem scale. Because they do not capture this effect, standard approaches overestimate ecosystem photosynthesis and daytime respiration in the first half of the growing season at our site, and inaccurately portray ecosystem photosynthetic light-use efficiency. These findings revise our understanding of forest-atmosphere carbon exchange, and provide a basis for investigating how leaf-level physiological dynamics manifest at the canopy scale in other ecosystems.

  6. Community photosynthesis of aquatic macrophytes

    DEFF Research Database (Denmark)

    Binzer, T.; Sand-Jensen, K.; Middelboe, A. L.

    2006-01-01

    We compared 190 photosynthesis-irradiance (P-E) experiments with single- and multispecies communities of macroalgae and vascular plants from freshwater and marine habitats. We found a typical hyperbolic P-E relation in all communities and no sign of photosaturation or photoinhibition of photosynt......We compared 190 photosynthesis-irradiance (P-E) experiments with single- and multispecies communities of macroalgae and vascular plants from freshwater and marine habitats. We found a typical hyperbolic P-E relation in all communities and no sign of photosaturation or photoinhibition...

  7. A roadmap for improving the representation of photosynthesis in Earth system models.

    Science.gov (United States)

    Rogers, Alistair; Medlyn, Belinda E; Dukes, Jeffrey S; Bonan, Gordon; von Caemmerer, Susanne; Dietze, Michael C; Kattge, Jens; Leakey, Andrew D B; Mercado, Lina M; Niinemets, Ülo; Prentice, I Colin; Serbin, Shawn P; Sitch, Stephen; Way, Danielle A; Zaehle, Sönke

    2017-01-01

    Accurate representation of photosynthesis in terrestrial biosphere models (TBMs) is essential for robust projections of global change. However, current representations vary markedly between TBMs, contributing uncertainty to projections of global carbon fluxes. Here we compared the representation of photosynthesis in seven TBMs by examining leaf and canopy level responses of photosynthetic CO 2 assimilation (A) to key environmental variables: light, temperature, CO 2 concentration, vapor pressure deficit and soil water content. We identified research areas where limited process knowledge prevents inclusion of physiological phenomena in current TBMs and research areas where data are urgently needed for model parameterization or evaluation. We provide a roadmap for new science needed to improve the representation of photosynthesis in the next generation of terrestrial biosphere and Earth system models. No claim to original US Government works New Phytologist © 2016 New Phytologist Trust.

  8. Enhancing (crop) plant photosynthesis by introducing novel genetic diversity.

    Science.gov (United States)

    Dann, Marcel; Leister, Dario

    2017-09-26

    Although some elements of the photosynthetic light reactions might appear to be ideal, the overall efficiency of light conversion to biomass has not been optimized during evolution. Because crop plants are depleted of genetic diversity for photosynthesis, efforts to enhance its efficiency with respect to light conversion to yield must generate new variation. In principle, three sources of natural variation are available: (i) rare diversity within extant higher plant species, (ii) photosynthetic variants from algae, and (iii) reconstruction of no longer extant types of plant photosynthesis. Here, we argue for a novel approach that outsources crop photosynthesis to a cyanobacterium that is amenable to adaptive evolution. This system offers numerous advantages, including a short generation time, virtually unlimited population sizes and high mutation rates, together with a versatile toolbox for genetic manipulation. On such a synthetic bacterial platform, 10 000 years of (crop) plant evolution can be recapitulated within weeks. Limitations of this system arise from its unicellular nature, which cannot reproduce all aspects of crop photosynthesis. But successful establishment of such a bacterial host for crop photosynthesis promises not only to enhance the performance of eukaryotic photosynthesis but will also reveal novel facets of the molecular basis of photosynthetic flexibility.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Author(s).

  9. Broadband Wireline Provider Service: Cable Modem - Other; BBRI_cableOther12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via "Cable Modem - Other" technology. Broadband availability is...

  10. Rhode Island crystalline repository siting project: Technical progress report, Calendar year 1986

    International Nuclear Information System (INIS)

    Vild, B.

    1987-01-01

    A Nuclear Waste Fund established by the Nuclear Waste Policy Act of 1982 provides financial support to affected states to participate in the high-level radioactive waste repository siting program of the US Department of Energy. In Rhode Island, that function was performed by a multidisciplinary Project Review Team consisting of staff from three State agencies. Members of the Review Team attended several meetings in 1986 to discuss mutual concerns with Federal, State and Tribal officials. Comments were developed on DOE's Draft Area Recommendation Report. Members of the Review Team also testified at a public hearing in Providence on the Draft ARR, and developed and distributed a public information booklet. In May, Secretary of Energy John Herrington announced the suspension of the crystalline repository siting program. The remainder of the year was spent monitoring litigation challenging that decision and pending legislation. Administrative phase-down of the program was essentially complete by the close of the calendar year

  11. Elements Required for an Efficient NADP-Malic Enzyme Type C4 Photosynthesis1[C][W][OPEN

    Science.gov (United States)

    Wang, Yu; Long, Stephen P.; Zhu, Xin-Guang

    2014-01-01

    C4 photosynthesis has higher light, nitrogen, and water use efficiencies than C3 photosynthesis. Although the basic anatomical, cellular, and biochemical features of C4 photosynthesis are well understood, the quantitative significance of each element of C4 photosynthesis to the high photosynthetic efficiency are not well defined. Here, we addressed this question by developing and using a systems model of C4 photosynthesis, which includes not only the Calvin-Benson cycle, starch synthesis, sucrose synthesis, C4 shuttle, and CO2 leakage, but also photorespiration and metabolite transport between the bundle sheath cells and mesophyll cells. The model effectively simulated the CO2 uptake rates, and the changes of metabolite concentrations under varied CO2 and light levels. Analyses show that triose phosphate transport and CO2 leakage can help maintain a high photosynthetic rate by balancing ATP and NADPH amounts in bundle sheath cells and mesophyll cells. Finally, we used the model to define the optimal enzyme properties and a blueprint for C4 engineering. As such, this model provides a theoretical framework for guiding C4 engineering and studying C4 photosynthesis in general. PMID:24521879

  12. City of Rhodes: residents' attitudes toward tourism impacts and development

    OpenAIRE

    Pappas, Nikolaos

    2011-01-01

    One of the most important issues of research in tourism is the exploration of residents' attitudes in local communities, since viable and sustainable tourism development can only be successful when it serves the actual needs and demands of the destination’s population, and any tourism evolution is directly dependant on locals’ acceptance and support. The purpose of this paper is to examine the host population perceptions in the city of Rhodes toward economic, social, and environmental tourism...

  13. The effect of irradiance on long-term skeletal growth and net photosynthesis in Galaxea fascicularis under four light conditions.

    NARCIS (Netherlands)

    Schutter, M.; Velthoven, van B.; Janse, M.; Osinga, R.; Janssen, M.G.J.; Wijffels, R.H.; Verreth, J.A.J.

    2008-01-01

    The relation between irradiance, skeletal growth and net photosynthesis was studied for the scleractinian coral Galaxea fascicularis to provide experimental evidence for mediation of light-enhanced calcification through photosynthesis. The hypothesis was tested that skeletal growth and

  14. Soil Temperature Triggers the Onset of Photosynthesis in Korean Pine

    Science.gov (United States)

    Wu, Jiabing; Guan, Dexin; Yuan, Fenhui; Wang, Anzhi; Jin, Changjie

    2013-01-01

    In forest ecosystems, the onset of spring photosynthesis may have an important influence on the annual carbon balance. However, triggers for the onset of photosynthesis have yet to be clearly identified, especially for temperate evergreen conifers. The effects of climatic factors on recovery of photosynthetic capacity in a Korean pine forest were investigated in the field. No photosynthesis was detectable when the soil temperature was below 0°C even if the air temperature was far beyond 15°C. The onset of photosynthesis and sap flow was coincident with the time of soil thawing. The rates of recovery of photosynthetic capacity highly fluctuated with air temperature after onset of photosynthesis, and intermittent frost events remarkably inhibited the photosynthetic capacity of the needles. The results suggest that earlier soil thawing is more important than air temperature increases in triggering the onset of photosynthesis in Korean pine in temperate zones under global warming scenarios. PMID:23755227

  15. Recruitment of pre-existing networks during the evolution of C4 photosynthesis.

    Science.gov (United States)

    Reyna-Llorens, Ivan; Hibberd, Julian M

    2017-09-26

    During C 4 photosynthesis, CO 2 is concentrated around the enzyme RuBisCO. The net effect is to reduce photorespiration while increasing water and nitrogen use efficiencies. Species that use C 4 photosynthesis have evolved independently from their C 3 ancestors on more than 60 occasions. Along with mimicry and the camera-like eye, the C 4 pathway therefore represents a remarkable example of the repeated evolution of a highly complex trait. In this review, we provide evidence that the polyphyletic evolution of C 4 photosynthesis is built upon pre-existing metabolic and genetic networks. For example, cells around veins of C 3 species show similarities to those of the C 4 bundle sheath in terms of C 4 acid decarboxylase activity and also the photosynthetic electron transport chain. Enzymes of C 4 photosynthesis function together in gluconeogenesis during early seedling growth of C 3 Arabidopsis thaliana Furthermore, multiple C 4 genes appear to be under control of both light and chloroplast signals in the ancestral C 3 state. We, therefore, hypothesize that relatively minor rewiring of pre-existing genetic and metabolic networks has facilitated the recurrent evolution of this trait. Understanding how these changes are likely to have occurred could inform attempts to install C 4 traits into C 3 crops.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Author(s).

  16. When growth and photosynthesis don't match: implications for carbon balance models

    Science.gov (United States)

    Medlyn, B.; Mahmud, K.; Duursma, R.; Pfautsch, S.; Campany, C.

    2017-12-01

    Most models of terrestrial plant growth are based on the principle of carbon balance: that growth can be predicted from net uptake of carbon via photosynthesis. A key criticism leveled at these models by plant physiologists is that there are many circumstances in which plant growth appears to be independent of photosynthesis: for example, during the onset of drought, or with rising atmospheric CO2 concentration. A crucial problem for terrestrial carbon cycle models is to develop better representations of plant carbon balance when there is a mismatch between growth and photosynthesis. Here we present two studies providing insight into this mismatch. In the first, effects of root restriction on plant growth were examined by comparing Eucalyptus tereticornis seedlings growing in containers of varying sizes with freely-rooted seedlings. Root restriction caused a reduction in photosynthesis, but this reduction was insufficient to explain the even larger reduction observed in growth. We applied data assimilation to a simple carbon balance model to quantify the response of carbon balance as a whole in this experiment. We inferred that, in addition to photosynthesis, there are significant effects of root restriction on growth respiration, carbon allocation, and carbohydrate utilization. The second study was carried out at the EucFACE Free-Air CO2 Enrichment experiment. At this experiment, photosynthesis of the overstorey trees is increased with enriched CO2, but there is no significant effect on above-ground productivity. These mature trees have reached their maximum height but are at significant risk of canopy loss through disturbance, and we hypothesized that additional carbon taken up through photosynthesis is preferentially allocated to storage rather than growth. We tested this hypothesis by measuring stemwood non-structural carbohydrates (NSC) during a psyllid outbreak that completely defoliated the canopy in 2015. There was a significant drawdown of NSC during

  17. New Concept of Photosynthesis

    Directory of Open Access Journals (Sweden)

    Komissarov Gennadiy Germanovich

    2014-12-01

    Full Text Available The history of the formation of a new concept of photosynthesis proposed by the author is considered for the period since 1966 to 2013. Its essence consists in the following facts: the photosynthetic oxygen (hydrogen source is not water, but exo- and endogenous hydrogen peroxide; thermal energy is a necessary part of the photosynthetic process; along with the carbon dioxide the air (oxygen, inert gases is included in the photosynthetic equation. The mechanism of the photovoltaic (Becquerel effect in films of chlorophyll and its synthetic analogue - phthalocyanine are briefly touched upon in the article. The article presents the works on artificial photosynthesis performed in the laboratory of Photobionics of N.N. Semenov Institute of Chemical Physics, RAS.

  18. Salinity critical threshold values for photosynthesis of two cosmopolitan seaweed species: providing baselines for potential shifts on seaweed assemblages.

    Science.gov (United States)

    Scherner, Fernando; Ventura, Robson; Barufi, José Bonomi; Horta, Paulo Antunes

    2013-10-01

    Climate change has increased precipitation in several South American regions leading to higher freshwater inputs into marine systems with potential to cause salinity declines along the coast. The current salinity profile on the southern coast of Brazil was surveyed during four years providing a baseline of the current salinity pattern in the region. Additionally, the effects of salinity decreases on the photosynthesis of the seaweeds Ulva lactuca and Sargassum stenophyllum were investigated in laboratory. Seaweeds were cultured at salinities 5, 15 and 34 and at the mean winter and summer temperatures. Photosynthetic performance was measured following 24 and 96 h from the beginning of experiment. U. lactuca remained practically unaltered by low salinities while S. stenophyllum presented declines of important photosynthetic parameters. This is due to the different regulation abilities of energy distribution at the PSII of the two species. These differences have potential to lead to seaweed community shifts. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Techniques in studies of photosynthesis

    International Nuclear Information System (INIS)

    Kumarasinghe, K.S.

    1990-01-01

    The use of both stable and radioactive isotopes has led to major advances in the understanding of the basic mechanisms of photosynthesis. An early use of isotopic material in photosynthetic investigations was the demonstration using 18 O, that O 2 evolved in photosynthesis was derived from water rather than from CO 2 . When the long-lived isotope of carbon, 14 C, became available in 1945, its use, coupled with two-dimensional chromatography developed a few years earlier, enabled Calvin and Benson (1948) to devise experiments to elucidate the pathway of photosynthetic 14 CO 2 fixation, 12 refs, 6 figs, 10 tabs

  20. The paleobiological record of photosynthesis.

    Science.gov (United States)

    William Schopf, J

    2011-01-01

    Fossil evidence of photosynthesis, documented in Precambrian sediments by microbially laminated stromatolites, cyanobacterial microscopic fossils, and carbon isotopic data consistent with the presence of Rubisco-mediated CO2-fixation, extends from the present to ~3,500 million years ago. Such data, however, do not resolve time of origin of O2-producing photoautotrophy from its anoxygenic, bacterial, evolutionary precursor. Though it is well established that Earth's ecosystem has been based on autotrophy since its very early stages, the time of origin of oxygenic photosynthesis, more than 2,450 million years ago, has yet to be established.

  1. Surveillance of Travel-Related Mosquito-borne Illness in Rhode Island.

    Science.gov (United States)

    Alang, Neha; Glavis-Bloom, Justin; Alexander-Scott, Nicole; Mermel, Leonard A; Mileno, Maria D

    2016-07-01

    Malaria and Dengue are some of the common infections occurring in persons traveling to countries endemic for these infections. Chinkungunya virus infection is another illness that can occur in people who have travelled to areas endemic for chikungunya virus infection. Herein we report cases of malaria, dengue, and chikungunya in Newport Hospital, The Miriam Hospital and Rhode Island Hospital between January 1, 2010 and December 31, 2014. [Full article available at http://rimed.org/rimedicaljournal-2016-07.asp, free with no login].

  2. Challenges in Understanding Photosynthesis in a University Introductory Biosciences Class

    Science.gov (United States)

    Södervik, Ilona; Virtanen, Viivi; Mikkilä-Erdmann, Mirjamaija

    2015-01-01

    University students' understanding of photosynthesis was examined in a large introductory biosciences class. The focus of this study was to first examine the conceptions of photosynthesis among students in class and then to investigate how a certain type of text could enhance students' understanding of photosynthesis. The study was based on pre-…

  3. Technical progress report: Rhode Island crystalline repository project, calendar year 1985

    International Nuclear Information System (INIS)

    Vild, B.F.

    1985-01-01

    A Nuclear Waste Fund established by the Nuclear Waste Policy Act of 1982 provides financial support to affected states to participate in the high-level radioactive waste repository siting program of the US Department of Energy. In Rhode Island, that function is performed by a multidisciplinary Project Review Team consisting of staff from three State agencies. Members of the Review Team attended several meetings in 1985 to voice their concerns directly to DOE. Written comments were also submitted on draft plans and reports. Among the issues raised were inconsistencies in the geologic and environmental data used to screen potential repository sites, the role of Monitored Retrievable Storage (MRS) in the repository program, and regulations regarding the transportation and storage of nuclear waste. The Review Team also began work on a public information booklet describing the repository program in nontechnical terms. That booklet will be distributed widely upon completion

  4. Profiles of medicinal cannabis patients attending compassion centers in rhode island.

    Science.gov (United States)

    Zaller, Nickolas; Topletz, Ariel; Frater, Susan; Yates, Gail; Lally, Michelle

    2015-01-01

    Little is understood regarding medicinal marijuana dispensary users. We sought to characterize socio-demographics and reasons for medicinal marijuana use among medical cannabis dispensary patients in Rhode Island. Participants (n=200) were recruited from one of two Compassion Centers in Rhode Island and asked to participate in a short survey, which included assessment of pain interference using the Brief Pain Inventory (BPI). The majority of participants were male (73%), Caucasian (80%), college educated (68%), and had health insurance (89%). The most common reason for medicinal marijuana use was determined to be chronic pain management. Participants were more likely to have BPI pain interference scores of > 5 if they were older (OR: 1.36, 95% CI: 1.04-1.78) or reported using cannabis as a substitute for prescription medications (OR: 2.47, 95% CI: 1.23-4.95), and were less likely to have interference scores of >5 if they had higher income levels (OR: 0.53, 95% CI: 0.40-0.70) or reported having ever received treatment for an alcohol use disorder. One-fifth of participants had a history of a drug or alcohol use disorder. Most participants report that medicinal cannabis improves their pain symptomology, and are interested in alternative treatment options to opioid-based treatment regimens.

  5. Numerical simulation of groundwater and surface-water interactions in the Big River Management Area, central Rhode Island

    Science.gov (United States)

    Masterson, John P.; Granato, Gregory E.

    2013-01-01

    The Rhode Island Water Resources Board is considering use of groundwater resources from the Big River Management Area in central Rhode Island because increasing water demands in Rhode Island may exceed the capacity of current sources. Previous water-resources investigations in this glacially derived, valley-fill aquifer system have focused primarily on the effects of potential groundwater-pumping scenarios on streamflow depletion; however, the effects of groundwater withdrawals on wetlands have not been assessed, and such assessments are a requirement of the State’s permitting process to develop a water supply in this area. A need for an assessment of the potential effects of pumping on wetlands in the Big River Management Area led to a cooperative agreement in 2008 between the Rhode Island Water Resources Board, the U.S. Geological Survey, and the University of Rhode Island. This partnership was formed with the goal of developing methods for characterizing wetland vegetation, soil type, and hydrologic conditions, and monitoring and modeling water levels for pre- and post-water-supply development to assess potential effects of groundwater withdrawals on wetlands. This report describes the hydrogeology of the area and the numerical simulations that were used to analyze the interaction between groundwater and surface water in response to simulated groundwater withdrawals. The results of this analysis suggest that, given the hydrogeologic conditions in the Big River Management Area, a standard 5-day aquifer test may not be sufficient to determine the effects of pumping on water levels in nearby wetlands. Model simulations showed water levels beneath Reynolds Swamp declined by about 0.1 foot after 5 days of continuous pumping, but continued to decline by an additional 4 to 6 feet as pumping times were increased from a 5-day simulation period to a simulation period representative of long-term average monthly conditions. This continued decline in water levels with

  6. Water relations and photosynthesis along an elevation gradient for Artemisia tridentata during an historic drought.

    Science.gov (United States)

    Reed, Charlotte C; Loik, Michael E

    2016-05-01

    Quantifying the variation in plant-water relations and photosynthesis over environmental gradients and during unique events can provide a better understanding of vegetation patterns in a future climate. We evaluated the hypotheses that photosynthesis and plant water potential would correspond to gradients in precipitation and soil moisture during a lengthy drought, and that experimental water additions would increase photosynthesis for the widespread evergreen shrub Artemisia tridentata ssp. vaseyana. We quantified abiotic conditions and physiological characteristics for control and watered plants at 2135, 2315, and 2835 m near Mammoth Lakes, CA, USA, at the ecotone of the Sierra Nevada and Great Basin ecoregions. Snowfall, total precipitation, and soil moisture increased with elevation, but air temperature and soil N content did not. Plant water potential (Ψ), stomatal conductance (g s), maximum photosynthetic rate (A max), carboxylation rate (V cmax), and electron transport rate (J max) all significantly increased with elevations. Addition of water increased Ψ, g s, J max, and A max only at the lowest elevation; g s contributed about 30 % of the constraints on photosynthesis at the lowest elevation and 23 % at the other two elevations. The physiology of this foundational shrub species was quite resilient to this 1-in-1200 year drought. However, plant water potential and photosynthesis corresponded to differences in soil moisture across the gradient. Soil re-wetting in early summer increased water potential and photosynthesis at the lowest elevation. Effects on water relations and photosynthesis of this widespread, cold desert shrub species may be disproportionate at lower elevations as drought length increases in a future climate.

  7. [Experimental study on crop photosynthesis, transpiration and high efficient water use].

    Science.gov (United States)

    Wang, Huixiao; Liu, Changming

    2003-10-01

    It is well known that the development of water-saving agriculture is a strategic choice for getting rid of the crisis of water shortage. In this paper, the crop photosynthesis, transpiration, stomatic behavior, and their affecting factors were studied in view of increasing the crop water use efficiency. The experimental results showed that there was a parabola relationship between photosynthesis and transpiration. The transpiration at the maximum photosynthesis was a critical value, above which, transpiration was the luxurious part. The luxurious transpiration could be controlled without affecting photosynthetic production. It is possible that the measures for increasing stomatic resistance and preventing transpiration could save water, and improve photosynthesis and yield as well. The photosynthesis rate increased with photosynthetic active radiation, and the light saturation point for photosynthesis existed. The light saturation point of dry treatment was much lower than that of wet treatment, and the relationship between transpiration and radiation was linear. When the photosynthetic active radiation was bigger than 1,000 mumol.m-2.s-1, some treatments could be carried out for decreasing transpiration and improving photosynthesis.

  8. Photosynthesis-related quantities for education and modeling.

    Science.gov (United States)

    Antal, Taras K; Kovalenko, Ilya B; Rubin, Andrew B; Tyystjärvi, Esa

    2013-11-01

    A quantitative understanding of the photosynthetic machinery depends largely on quantities, such as concentrations, sizes, absorption wavelengths, redox potentials, and rate constants. The present contribution is a collection of numbers and quantities related mainly to photosynthesis in higher plants. All numbers are taken directly from a literature or database source and the corresponding reference is provided. The numerical values, presented in this paper, provide ranges of values, obtained in specific experiments for specific organisms. However, the presented numbers can be useful for understanding the principles of structure and function of photosynthetic machinery and for guidance of future research.

  9. Preface: photosynthesis and hydrogen energy research for sustainability.

    Science.gov (United States)

    Tomo, Tatsuya; Allakhverdiev, Suleyman I

    2017-09-01

    Energy supply, climate change, and global food security are among the main chalenges facing humanity in the twenty-first century. Despite global energy demand is continuing to increase, the availability of low cost energy is decreasing. Together with the urgent problem of climate change due to CO 2 release from the combustion of fossil fuels, there is a strong requirement of developing the clean and renewable energy system for the hydrogen production. Solar fuel, biofuel, and hydrogen energy production gained unlimited possibility and feasibility due to understanding of the detailed photosynthetic system structures. This special issue contains selected papers on photosynthetic and biomimetic hydrogen production presented at the International Conference "Photosynthesis Research for Sustainability-2016", that was held in Pushchino (Russia), during June 19-25, 2016, with the sponsorship of the International Society of Photosynthesis Research (ISPR) and of the International Association for Hydrogen Energy (IAHE). This issue is intended to provide recent information on the photosynthetic and biohydrogen production to our readers.

  10. Investing in Low-Wage Workers: Lessons from Family Child Care in Rhode Island

    Science.gov (United States)

    Roder, Anne; Seavey, Dorie

    2006-01-01

    While child care is one of the fastest growing occupations in the country, most employment in this field is precarious and low-wage. Investing in Low-Wage Workers profiles the Day Care Justice Co-op, a group of largely Latina and African American women living and working in some of Rhode Island's poorest communities. Determined to improve family…

  11. Rhode Island Pension Reform: Implications and Opportunities for Education. Education Sector Policy Briefs

    Science.gov (United States)

    Herriot-Hatfield, Jennie; Monahan, Amy; Rosenberg, Sarah; Tucker, Bill

    2011-01-01

    On August 24, 2010, the state of Rhode Island received some outstanding news. Its yearlong, bipartisan effort to develop new policies to spur educational improvement was about to pay off. The state, along with eight others and the District of Columbia, was named a winner of the U.S. Department of Education's Race to the Top grant competition. The…

  12. Estimated medical cost savings in Rhode Island by implementation of a primary seat belt law

    Science.gov (United States)

    2008-09-01

    This report examines 2006 hospital discharge data reporting cases where the external cause of injury to a vehicle occupant was a motor vehicle crash to predict the estimated savings to Rhode Island if a primary seat belt law is implemented. The savin...

  13. Secondary Students' Interpretations of Photosynthesis and Plant Nutrition.

    Science.gov (United States)

    Ozay, Esra; Oztas, Haydar

    2003-01-01

    Studies misconceptions held by grade 9 students (14-15-years old) in Turkey about photosynthesis and plant nutrition. Uses a questionnaire to test students' conceptions and reports conflicting and often incorrect ideas about photosynthesis, respiration, and energy flow in plants. Suggests that there are difficulties in changing students' prior…

  14. Aerosol-induced thermal effects increase modelled terrestrial photosynthesis and transpiration

    International Nuclear Information System (INIS)

    Steiner, Allison L.; Chameides, W.L.

    2005-01-01

    Previous studies suggest that the radiative effects of atmospheric aerosols (reducing total radiation while increasing the diffuse fraction) can enhance terrestrial productivity. Here, simulations using a regional climate/terrestrial biosphere model suggest that atmospheric aerosols could also enhance terrestrial photosynthesis and transpiration through an interaction between solar radiation, leaf temperature and stomatal conductance. During midday, clear-sky conditions, sunlit-leaf temperatures can exceed the optimum for photosynthesis, depressing both photosynthesis and transpiration. Aerosols decrease surface solar radiation, thereby reducing leaf temperatures and enhancing sunlit-leaf photosynthesis and transpiration. This modelling study finds that, under certain conditions, this thermal response of aerosols can have a greater impact on photosynthesis and transpiration than the radiative response. This implies that a full understanding of the impact of aerosols on climate and the global carbon cycle requires consideration of the biophysical responses of terrestrial vegetation as well as atmospheric radiative and thermodynamic effects

  15. Elevated CO2 increases photosynthesis in fluctuating irradiance regardless of photosynthetic induction state

    NARCIS (Netherlands)

    Kaiser, Elias; Zhou, Dianfan; Heuvelink, Ep; Harbinson, Jeremy; Morales Sierra, A.; Marcelis, Leo F.M.

    2017-01-01

    Leaves are often exposed to fluctuating irradiance, which limits assimilation. Elevated CO2 enhances dynamic photosynthesis (i.e. photosynthesis in fluctuating irradiance) beyond its effects on steady-state photosynthesis rates. Studying the role of CO2 in dynamic photosynthesis is important for

  16. 76 FR 51383 - Commercial Leasing for Wind Power on the Outer Continental Shelf (OCS) Offshore Rhode Island and...

    Science.gov (United States)

    2011-08-18

    ... Rhode Island and Massachusetts recognizes the benefits of collaborating in the evaluation and potential... appropriate; (3) A preliminary schedule of proposed activities, including those leading to commercial...

  17. Models for estimating photosynthesis parameters from in situ production profiles

    Science.gov (United States)

    Kovač, Žarko; Platt, Trevor; Sathyendranath, Shubha; Antunović, Suzana

    2017-12-01

    The rate of carbon assimilation in phytoplankton primary production models is mathematically prescribed with photosynthesis irradiance functions, which convert a light flux (energy) into a material flux (carbon). Information on this rate is contained in photosynthesis parameters: the initial slope and the assimilation number. The exactness of parameter values is crucial for precise calculation of primary production. Here we use a model of the daily production profile based on a suite of photosynthesis irradiance functions and extract photosynthesis parameters from in situ measured daily production profiles at the Hawaii Ocean Time-series station Aloha. For each function we recover parameter values, establish parameter distributions and quantify model skill. We observe that the choice of the photosynthesis irradiance function to estimate the photosynthesis parameters affects the magnitudes of parameter values as recovered from in situ profiles. We also tackle the problem of parameter exchange amongst the models and the effect it has on model performance. All models displayed little or no bias prior to parameter exchange, but significant bias following parameter exchange. The best model performance resulted from using optimal parameter values. Model formulation was extended further by accounting for spectral effects and deriving a spectral analytical solution for the daily production profile. The daily production profile was also formulated with time dependent growing biomass governed by a growth equation. The work on parameter recovery was further extended by exploring how to extract photosynthesis parameters from information on watercolumn production. It was demonstrated how to estimate parameter values based on a linearization of the full analytical solution for normalized watercolumn production and from the solution itself, without linearization. The paper complements previous works on photosynthesis irradiance models by analysing the skill and consistency of

  18. Photosynthesis and the world food problem

    Directory of Open Access Journals (Sweden)

    Jerzy Poskuta

    2014-01-01

    Full Text Available Studies in the field of photosynthesis are particularly predisposed to play an important role in the solving of the main problem of today food for the world's growing population. The article presents data on the rate of population increase, the size of food production and yields of the most important crop plants. The relationship between the photosynthetic productivity of C3 and C4 plants and their yields is discussed. The problem of the rising atmospheric CO2 concentration and its influence on photosynthesis, photorespiration and accumulation of plant biomass is presented.

  19. The Path of Carbon in Photosynthesis

    Science.gov (United States)

    Bassham, J. A.; Calvin, Melvin

    1960-10-01

    Biosynthesis begins with photosynthesis. Green plants and other photosynthetic organisms use the energy of absorbed visible light to make organic compounds from inorganic compounds. These organic compounds are the starting point for all other biosynthetic pathways. The products of photosynthesis provide not only the substrate material but also chemical energy for all subsequent biosynthesis. For example, nonphotosynthetic organisms making fats from sugars would first break down the sugars to smaller organic molecules. Some of the smaller molecules might be oxidized with O{sub 2} to CO{sub 2} and water. These reactions are accompanied by a release of chemical energy because O{sub 2} and sugar have a high chemical potential energy towards conversion to CO{sub 2} and H{sub 2}O. In a biochemical system only part of this energy would be released as heat. The heat would be used to bring about the conversion of certain enzymic cofactors to their more energetic forms. These cofactors would then enter into specific enzymic reactions in such a way as to supply energy to drive reactions in the direction of fat synthesis. Fats would be formed from the small organic molecules resulting from the breakdown of sugars. Thus sugar, a photosynthetic product, can supply both the energy and the material for the biosynthesis of fats.

  20. THE PATH OF CARBON IN PHOTOSYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Bassham, J.A.; Calvin, Melvin

    1960-10-01

    Biosynthesis begins with photosynthesis. Green plants and other photosynthetic organisms use the energy of absorbed visible light to make organic compounds from inorganic compounds. These organic compounds are the starting point for all other biosynthetic pathways. The products of photosynthesis provide not only the substrate material but also chemical energy for all subsequent biosynthesis. For example, nonphotosynthetic organisms making fats from sugars would first break down the sugars to smaller organic molecules. Some of the smaller molecules might be oxidized with O{sub 2} to CO{sub 2} and water. These reactions are accompanied by a release of chemical energy because O{sub 2} and sugar have a high chemical potential energy towards conversion to CO{sub 2} and H{sub 2}O. In a biochemical system only part of this energy would be released as heat. The heat would be used to bring about the conversion of certain enzymic cofactors to their more energetic forms. These cofactors would then enter into specific enzymic reactions in such a way as to supply energy to drive reactions in the direction of fat synthesis. Fats would be formed from the small organic molecules resulting from the breakdown of sugars. Thus sugar, a photosynthetic product, can supply both the energy and the material for the biosynthesis of fats.

  1. Photosynthesis 2008 Gordon Research Conferences - June 22-27, 2008

    Energy Technology Data Exchange (ETDEWEB)

    Willem Vermaas

    2009-08-28

    Photosynthesis is the most prevalent, natural way to convert solar energy to chemical energy in living systems, and is a major mechanism to ameliorate rising CO2 levels in the atmosphere and to contribute to sustainable biofuels production. Photosynthesis is a particularly interdisciplinary field of research, with contributions from plant and microbial physiology, biochemistry, spectroscopy, etc. The Photosynthesis GRC is a venue by which scientists with expertise in complementary approaches such as solar energy conversion, molecular mechanisms of electron transfer, and 'systems biology' (molecular physiology) of photosynthetic organisms come together to exchange data and ideas and to forge new collaborations. The 2008 Photosynthesis GRC will focus on important new findings related to, for example: (1) function, structure, assembly, degradation, motility and regulation of photosynthetic complexes; (2) energy and electron transfer in photosynthetic systems; regulation and rate limitations; (3) synthesis, degradation and regulation of cofactors (pigments, etc.); (4) functional, structural and regulatory interactions between photosynthesis and the physiology of the organism; (5) organisms with unusual photosynthetic properties, and insights from metagenomics and evolution; and (6) bioenergy strategies involving solar energy conversion, and practical applications for photosynthetic organisms.

  2. Broadband Wireline Provider Service: Cable Modem - DOCSIS 3.0; BBRI_cableDOCSIS12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via "Cable Modem - DOCSIS 3.0" technology. Broadband availability is...

  3. Collection and analysis of remotely sensed data from the Rhode River Estuary Watershed

    Science.gov (United States)

    Jenkins, D. W.; Williamson, F. S. L.

    1973-01-01

    The remote sensing study to survey the Rhode River watershed for spray irrigation with secondarily treated sewage is reported. The standardization of Autumn coloration changes with Munsell color chips is described along with the mapping of old field vegetation for the spray irrigation project. The interpretation and verification of salt marsh vegetation by remote sensing of the water shed is discussed.

  4. Scientific Conceptions of Photosynthesis among Primary School Pupils and Student Teachers of Biology

    Directory of Open Access Journals (Sweden)

    Darja Skribe Dimec

    2017-03-01

    Full Text Available Photosynthesis is the most important biochemical process on Earth. Most living beings depend on it directly or indirectly. Knowledge about photosynthesis enables us to understand how the world functions as an ecosystem and how photosynthesis acts as a bridge between the non-living and living worlds. It is, therefore, understandable that photosynthesis is included in national curricula around the world. The practice unfortunately shows that students at all school levels mostly learn about photosynthesis by rote. Consequently, they have difficulties understanding this vital process. Research also shows many misconceptions in relation to photosynthesis among students of different ages. Based on these, the main aim of our study was to explore the scientific conceptions about photosynthesis held by primary school pupils and student teachers of biology. Data were collected using a questionnaire containing seven biology content questions. The sample consisted of 634 participants, 427 primary school pupils (aged 11–14, and 207 student teachers of biology (aged 20–23. We found that the populations of primary school pupils and student teachers of biology differ greatly concerning scientific conceptions of photosynthesis. The student teachers showed good and complex understanding of photosynthesis, while pupils showed some misconceptions (location of chlorophyll and photosynthesis in a plant, transformation of energy in photosynthesis. Analysis of the development of scientific conceptions about photosynthesis with age showed that there is very little progress among primary school pupils and none among biology student teachers. More involvement of student teachers of biology in practical work at primary schools during their study was suggested to make student teachers aware of, and better understand pupils’ misconceptions.

  5. 77 FR 30551 - Commercial Renewable Energy Transmission on the Outer Continental Shelf (OCS) Offshore Rhode...

    Science.gov (United States)

    2012-05-23

    ... transmission grid on the Rhode Island mainland to Block Island. Deepwater Wind proposes to connect an onshore... Island LLC (Deepwater Wind) Transmission System (BITS) proposal submitted to the Bureau of Ocean Energy... electrical power from Deepwater Wind's proposed 30 megawatt (MW) offshore wind energy project located in...

  6. 33 CFR 165.121 - Safety and Security Zones: High Interest Vessels, Narragansett Bay, Rhode Island.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety and Security Zones: High... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION... Guard District § 165.121 Safety and Security Zones: High Interest Vessels, Narragansett Bay, Rhode...

  7. The 3D Elevation Program: summary for Rhode Island

    Science.gov (United States)

    Carswell, William J.

    2013-01-01

    Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of Rhode Island, elevation data are critical for flood risk management, natural resources conservation, coastal zone management, sea level rise and subsidence, agriculture and precision farming, and other business uses. Today, high-quality light detection and ranging (lidar) data are the sources for creating elevation models and other elevation datasets. Federal, State, and local agencies work in partnership to (1) replace data, on a national basis, that are (on average) 30 years old and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The new 3D Elevation Program (3DEP) initiative (Snyder, 2012a,b), managed by the U.S. Geological Survey (USGS), responds to the growing need for high-quality topographic data and a wide range of other three-dimensional representations of the Nation’s natural and constructed features.

  8. Increase in Drug Overdose Deaths Involving Fentanyl-Rhode Island, January 2012-March 2014.

    Science.gov (United States)

    Mercado, Melissa C; Sumner, Steven A; Spelke, M Bridget; Bohm, Michele K; Sugerman, David E; Stanley, Christina

    2018-03-01

    This study identified sociodemographic, substance use, and multiple opioid prescriber and dispenser risk factors among drug overdose decedents in Rhode Island, in response to an increase in overdose deaths (ODs) involving fentanyl. This cross-sectional investigation comprised all ODs reviewed by Rhode Island's Office of the State Medical Examiners (OSME) during January 2012 to March 2014. Data for 536 decedents were abstracted from OSME's charts, death certificates, toxicology reports, and Prescription Monitoring Program (PMP) databases. Decedents whose cause of death involved illicit fentanyl (N = 69) were compared with decedents whose causes of death did not involve fentanyl (other drug decedents; N = 467). Illicit-fentanyl decedents were younger than other drug decedents (P = 0.005). While more other-drug decedents than illicit fentanyl decedents had postmortem toxicological evidence of consuming heroin (31.9% vs 19.8%, P < 0.001) and various pharmaceutical substances (P = 0.002-0.027), third party reports indicated more recent heroin use among illicit fentanyl decedents (62.3% vs 45.6%, P = 0.002). Approximately 35% of decedents filled an opioid prescription within 90 days of death; of these, one-third had a mean daily dosage greater than 100 morphine milligram equivalents (MME/day). Most decedents' opioid prescriptions were filled at one to two dispensers (83.9%) and written by one to two prescribers (75.8%). Notably, 29.2% of illicit fentanyl and 10.5% of other drug decedents filled prescriptions for buprenorphine, which is used to treat opioid use disorders. Illicit-fentanyl deaths frequently involved other illicit drugs (e.g., cocaine, heroin). The proportion of all decedents acquiring greater than 100 MME/day prescription dosages written and/or filled by few prescribers and dispensers is concerning. To protect patients, prescribers and dispensers should review PMP records and substance abuse history prior to providing opioids.

  9. "AfterZone:" Outcomes for Youth Participating in Providence's Citywide After-School System. Executive Summary

    Science.gov (United States)

    Kauh, Tina J.

    2011-01-01

    This executive summary highlights the main findings from our participation and outcomes analysis of the "AfterZone" initiative--a citywide system-building effort in Providence, Rhode Island, that aims to provide high-quality, accessible out-of-school-time services to middle school youth. The summary briefly defines the AfterZone's unique…

  10. Reevaluation of the plant "gemstones": Calcium oxalate crystals sustain photosynthesis under drought conditions.

    Science.gov (United States)

    Tooulakou, Georgia; Giannopoulos, Andreas; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Dotsika, Elissavet; Orkoula, Malvina G; Kontoyannis, Christos G; Fasseas, Costas; Liakopoulos, Georgios; Klapa, Maria I; Karabourniotis, George

    2016-09-01

    Land plants face the perpetual dilemma of using atmospheric carbon dioxide for photosynthesis and losing water vapors, or saving water and reducing photosynthesis and thus growth. The reason behind this dilemma is that this simultaneous exchange of gases is accomplished through the same minute pores on leaf surfaces, called stomata. In a recent study we provided evidence that pigweed, an aggressive weed, attenuates this problem exploiting large crystals of calcium oxalate as dynamic carbon pools. This plant is able to photosynthesize even under drought conditions, when stomata are closed and water losses are limited, using carbon dioxide from crystal decomposition instead from the atmosphere. Abscisic acid, an alarm signal that causes stomatal closure seems to be implicated in this function and for this reason we named this path "alarm photosynthesis." The so-far "enigmatic," but highly conserved and widespread among plant species calcium oxalate crystals seem to play a crucial role in the survival of plants.

  11. Manganese and the Evolution of Photosynthesis

    Science.gov (United States)

    Fischer, Woodward W.; Hemp, James; Johnson, Jena E.

    2015-09-01

    Oxygenic photosynthesis is the most important bioenergetic event in the history of our planet—it evolved once within the Cyanobacteria, and remained largely unchanged as it was transferred to algae and plants via endosymbiosis. Manganese plays a fundamental role in this history because it lends the critical redox behavior of the water-oxidizing complex of photosystem II. Constraints from the photoassembly of the Mn-bearing water-oxidizing complex fuel the hypothesis that Mn(II) once played a key role as an electron donor for anoxygenic photosynthesis prior to the evolution of oxygenic photosynthesis. Here we review the growing body of geological and geochemical evidence from the Archean and Paleoproterozoic sedimentary records that supports this idea and demonstrates that the oxidative branch of the Mn cycle switched on prior to the rise of oxygen. This Mn-oxidizing phototrophy hypothesis also receives support from the biological record of extant phototrophs, and can be made more explicit by leveraging constraints from structural biology and biochemistry of photosystem II in Cyanobacteria. These observations highlight that water-splitting in photosystem II evolved independently from a homodimeric ancestral type II reaction center capable of high potential photosynthesis and Mn(II) oxidation, which is required by the presence of homologous redox-active tyrosines in the modern heterodimer. The ancestral homodimer reaction center also evolved a C-terminal extension that sterically precluded standard phototrophic electron donors like cytochrome c, cupredoxins, or high-potential iron-sulfur proteins, and could only complete direct oxidation of small molecules like Mn2+, and ultimately water.

  12. Artificial photosynthesis combines biology with technology for sustainable energy transformation

    Science.gov (United States)

    Moore, Thomas A.; Moore, Ana L.; Gust, Devens

    2013-03-01

    Photosynthesis supports the biosphere. Currently, human activity appropriates about one fourth of terrestrial photosynthetic net primary production (NPP) to support our GDP and nutrition. The cost to Earth systems of "our cut" of NPP is thought to be rapidly driving several Earth systems outside of bounds that were established on the geological time scale. Even with a fundamental realignment of human priorities, changing the unsustainable trajectory of the anthropocene will require reengineering photosynthesis to more efficiently meet human needs. Artificial photosynthetic systems are envisioned that can both supply renewable fuels and serve as platforms for exploring redesign strategies for photosynthesis. These strategies can be used in the nascent field of synthetic biology to make vast, much needed improvements in the biomass production efficiency of photosynthesis.

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

    Science.gov (United States)

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

    2014-01-01

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

  14. Photosynthesis: The Path of Carbon in Photosynthesis and the Primary Quantum Conversion Act of Photosynthesis

    Science.gov (United States)

    Calvin, Melvin

    1952-11-22

    This constitutes a review of the path of carbon in photosynthesis as it has been elaborated through the summer of 1952, with particular attention focused on those aspects of carbon metabolism and its variation which have led to some direct information regarding the primary quantum conversion act. An introduction to the arguments which have been adduced in support of the idea that chlorophyll is a physical sensitizer handing its excitation on to thioctic acid, a compound containing a strained 1, 2 -dithiolcyclopentane ring, is given.

  15. Underwater Photosynthesis of Submerged Plants – Recent Advances and Methods

    Science.gov (United States)

    Pedersen, Ole; Colmer, Timothy D.; Sand-Jensen, Kaj

    2013-01-01

    We describe the general background and the recent advances in research on underwater photosynthesis of leaf segments, whole communities, and plant dominated aquatic ecosystems and present contemporary methods tailor made to quantify photosynthesis and carbon fixation under water. The majority of studies of aquatic photosynthesis have been carried out with detached leaves or thalli and this selectiveness influences the perception of the regulation of aquatic photosynthesis. We thus recommend assessing the influence of inorganic carbon and temperature on natural aquatic communities of variable density in addition to studying detached leaves in the scenarios of rising CO2 and temperature. Moreover, a growing number of researchers are interested in tolerance of terrestrial plants during flooding as torrential rains sometimes result in overland floods that inundate terrestrial plants. We propose to undertake studies to elucidate the importance of leaf acclimation of terrestrial plants to facilitate gas exchange and light utilization under water as these acclimations influence underwater photosynthesis as well as internal aeration of plant tissues during submergence. PMID:23734154

  16. Increased sink strength offsets the inhibitory effect of sucrose on sugarcane photosynthesis.

    Science.gov (United States)

    Ribeiro, Rafael V; Machado, Eduardo C; Magalhães Filho, José R; Lobo, Ana Karla M; Martins, Márcio O; Silveira, Joaquim A G; Yin, Xinyou; Struik, Paul C

    2017-01-01

    Spraying sucrose inhibits photosynthesis by impairing Rubisco activity and stomatal conductance (g s ), whereas increasing sink demand by partially darkening the plant stimulates sugarcane photosynthesis. We hypothesized that the stimulatory effect of darkness can offset the inhibitory effect of exogenous sucrose on photosynthesis. Source-sink relationship was perturbed in two sugarcane cultivars by imposing partial darkness, spraying a sucrose solution (50mM) and their combination. Five days after the onset of the treatments, the maximum Rubisco carboxylation rate (V cmax ) and the initial slope of A-C i curve (k) were estimated by measuring leaf gas exchange and chlorophyll fluorescence. Photosynthesis was inhibited by sucrose spraying in both genotypes, through decreases in V cmax , k, g s and ATP production driven by electron transport (J atp ). Photosynthesis of plants subjected to the combination of partial darkness and sucrose spraying was similar to photosynthesis of reference plants for both genotypes. Significant increases in V cmax , g s and J atp and marginal increases in k were noticed when combining partial darkness and sucrose spraying compared with sucrose spraying alone. Our data also revealed that increases in sink strength due to partial darkness offset the inhibition of sugarcane photosynthesis caused by sucrose spraying, enhancing the knowledge on endogenous regulation of sugarcane photosynthesis through the source-sink relationship. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. Broadband Wireline Provider Service: Optical Carrier - Fiber to the End User; BBRI_fiber12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via "Optical Carrier - Fiber to the End User" technology. Broadband...

  18. Temporal and spatial transcriptomic and microRNA dynamics of CAM photosynthesis in pineapple.

    Science.gov (United States)

    Wai, Ching M; VanBuren, Robert; Zhang, Jisen; Huang, Lixian; Miao, Wenjing; Edger, Patrick P; Yim, Won C; Priest, Henry D; Meyers, Blake C; Mockler, Todd; Smith, J Andrew C; Cushman, John C; Ming, Ray

    2017-10-01

    The altered carbon assimilation pathway of crassulacean acid metabolism (CAM) photosynthesis results in an up to 80% higher water-use efficiency than C 3 photosynthesis in plants making it a potentially useful pathway for engineering crop plants with improved drought tolerance. Here we surveyed detailed temporal (diel time course) and spatial (across a leaf gradient) gene and microRNA (miRNA) expression patterns in the obligate CAM plant pineapple [Ananas comosus (L.) Merr.]. The high-resolution transcriptome atlas allowed us to distinguish between CAM-related and non-CAM gene copies. A differential gene co-expression network across green and white leaf diel datasets identified genes with circadian oscillation, CAM-related functions, and source-sink relations. Gene co-expression clusters containing CAM pathway genes are enriched with clock-associated cis-elements, suggesting circadian regulation of CAM. About 20% of pineapple microRNAs have diel expression patterns, with several that target key CAM-related genes. Expression and physiology data provide a model for CAM-specific carbohydrate flux and long-distance hexose transport. Together these resources provide a list of candidate genes for targeted engineering of CAM into C 3 photosynthesis crop species. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  19. Observed and predicted measurements of photosynthesis in a phytoplankton culture exposed to natural irradiance

    International Nuclear Information System (INIS)

    Marra, J.; Heinemann, K.; Landriau, G. Jr.

    1985-01-01

    Photosynthesis-irradiance (P-I) curves were produced (using artificial illumination) from samples taken at one or more times per day from a continuous culture illuminated with sunlight. The continuous culture housed an oxygen electrode used to measure photosynthesis semi-continuously. Rates of photosynthesis predicted from P-I curves agreed with photosynthesis observed in the culture only for days of low irradiance. For sunny days or for days of variable irradiance, P-I curves predicted neither the morning photosynthesis maximum nor the afternoon depression. Daily integrals of predicted and observed photosynthesis, however, were probably within the possible errors of measurement. (orig.)

  20. Auxin transport in leafy pea stem cuttings is partially driven by photosynthesis

    International Nuclear Information System (INIS)

    Kumpula, C.L.; Potter, J.R.

    1987-01-01

    When 14 C-IAA was applied to the apex of disbudded leafy pea stem cuttings (15 cm long), the movement of 14 C-IAA to the base of the cuttings after 24 h was influenced by the photosynthetic rate. In the absence of photosynthesis, light did not influence 14 C-IAA movement. Photosynthesis was altered by varying light, CO 2 concentration, or stomatal aperature (blocked with an antitranspirant). Radioactivity (identified by co-chromatography) was 25, 60, and 5% IAA, IAA-aspartate, and indolealdehyde respectively regardless of treatment. Adventitious root formation was reduced 50 to 95% and movement of IAA was inhibited 50 to 70% by decreasing gross photosynthesis 90 to 100%. Apparently, photosynthesis partially drives the movement of IAA from the apex to the base where roots arise. This gives a probably role of photosynthesis in rooting, because in this system virtually no rooting will take place without exogenous auxin and at least a low level of gross photosynthesis

  1. Photosynthesis efficiency for different wavelengths; Fotosynthese-efficiency bij verschillende golflengten

    Energy Technology Data Exchange (ETDEWEB)

    Snel, J.F.H.; Meinen, E.; Bruins, M.A.; Van Ieperen, W.; Hogewoning, S.W.; Marcelis, L.F.M. [Wageningen UR Glastuinbouw, Wageningen (Netherlands)

    2012-04-15

    LED lighting has recently been introduced into Dutch horticulture. LED development so far indicates that in the near future LED's will be more energy efficient than high pressure sodium lamps. Crop light interception and photosynthesis efficiency are wavelength dependent. Therefore, LED colours for maximum crop photosynthesis, growth and development should be identified. Wageningen UR has investigated light interception and photosynthesis at different wavelengths for tomato, cucumber and rose. Measuring protocols and equipment were developed for leaf photosynthesis measurements in the laboratory and in greenhouses. A crop simulation model was used for up-scaling the leaf level results to crop level photosynthesis. For the vegetable crops the photosynthesis spectra are very similar to the generalised photosynthesis spectrum. Red light is most efficient for leaf photosynthesis. Light from red (ca. 645nm) LED's was maximally 13% more efficient than High Pressure Sodium light. For reddish leaves of the rose cultivar Prestige, red LED light was up to 35% more efficient. These figures apply to the momentary efficiency of leaf photosynthesis at 100 {mu}mol.m{sup -2}.s{sup -1} (PAR) and suggest that use of red light can lead to higher photosynthesis, especially for certain rose cultivars [Dutch] LED verlichting heeft zijn intrede gedaan in de Nederlandse glastuinbouw. De LED ontwikkeling laat zien dat in de nabije toekomst LED's efficiënter zijn dan SON-T verlichting. Lichtonderschepping en fotosynthese efficiëntie zijn afhankelijk van de kleur van het licht. Voor optimale fotosynthese, groei en ontwikkeling zouden de beste LED kleuren uitgezocht moeten worden. Wageningen UR heeft lichtonderschepping en fotosynthese bij verschillende lichtkleuren onderzocht bij tomaat, komkommer en roos. Protocollen en apparatuur werden ontwikkeld voor meting van bladfotosynthese en lichtonderschepping in het laboratorium en in de kas. Met een gewassimulatiemodel werd de

  2. Acetylome analysis reveals the involvement of lysine acetylation in photosynthesis and carbon metabolism in the model cyanobacterium Synechocystis sp. PCC 6803.

    Science.gov (United States)

    Mo, Ran; Yang, Mingkun; Chen, Zhuo; Cheng, Zhongyi; Yi, Xingling; Li, Chongyang; He, Chenliu; Xiong, Qian; Chen, Hui; Wang, Qiang; Ge, Feng

    2015-02-06

    Cyanobacteria are the oldest known life form inhabiting Earth and the only prokaryotes capable of performing oxygenic photosynthesis. Synechocystis sp. PCC 6803 (Synechocystis) is a model cyanobacterium used extensively in research on photosynthesis and environmental adaptation. Posttranslational protein modification by lysine acetylation plays a critical regulatory role in both eukaryotes and prokaryotes; however, its extent and function in cyanobacteria remain unexplored. Herein, we performed a global acetylome analysis on Synechocystis through peptide prefractionation, antibody enrichment, and high accuracy LC-MS/MS analysis; identified 776 acetylation sites on 513 acetylated proteins; and functionally categorized them into an interaction map showing their involvement in various biological processes. Consistent with previous reports, a large fraction of the acetylation sites are present on proteins involved in cellular metabolism. Interestingly, for the first time, many proteins involved in photosynthesis, including the subunits of phycocyanin (CpcA, CpcB, CpcC, and CpcG) and allophycocyanin (ApcA, ApcB, ApcD, ApcE, and ApcF), were found to be lysine acetylated, suggesting that lysine acetylation may play regulatory roles in the photosynthesis process. Six identified acetylated proteins associated with photosynthesis and carbon metabolism were further validated by immunoprecipitation and Western blotting. Our data provide the first global survey of lysine acetylation in cyanobacteria and reveal previously unappreciated roles of lysine acetylation in the regulation of photosynthesis. The provided data set may serve as an important resource for the functional analysis of lysine acetylation in cyanobacteria and facilitate the elucidation of the entire metabolic networks and photosynthesis process in this model cyanobacterium.

  3. Exploring Undergraduates' Understanding of Photosynthesis Using Diagnostic Question Clusters

    Science.gov (United States)

    Parker, Joyce M.; Anderson, Charles W.; Heidemann, Merle; Merrill, John; Merritt, Brett; Richmond, Gail; Urban-Lurain, Mark

    2012-01-01

    We present a diagnostic question cluster (DQC) that assesses undergraduates' thinking about photosynthesis. This assessment tool is not designed to identify individual misconceptions. Rather, it is focused on students' abilities to apply basic concepts about photosynthesis by reasoning with a coordinated set of practices based on a few scientific…

  4. The Path of Carbon in Photosynthesis XIV.

    Science.gov (United States)

    Calvin, Melvin; Bassham, J. A.; Benson, A. A.; Kawaguchi, S.; Lynch, V. H.; Stepka, W.; Tolbert, N. E.

    1951-06-30

    It seems hardly necessary to repeat to an audience of this kind the importance of the process known as photosynthesis in the interaction and the interdependence of organisms and in the very existence of life as we know it. This process by which green plants are able to capture electromagnetic energy in the form of sunlight and transform it into stored chemical energy in the form of a wide variety of reduced (relative to carbon dioxide) carbon compounds provides the only major source of energy for the maintenance and propagation of all life.

  5. The Path of Carbon in Photosynthesis. XIV.

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Melvin; Bassham, J.A.; Benson, A.A.; Kawaguchi, S.; Lynch, V.H.; Stepka, W.; Tolbert, N.E.

    1951-06-30

    It seems hardly necessary to repeat to an audience of this kind the importance of the process known as photosynthesis in the interaction and the interdependence of organisms and in the very existence of life as we know it. This process by which green plants are able to capture electromagnetic energy in the form of sunlight and transform it into stored chemical energy in the form of a wide variety of reduced (relative to carbon dioxide) carbon compounds provides the only major source of energy for the maintenance and propagation of all life.

  6. Conceptual change through the use of student-generated analogies of photosynthesis and respiration by college non-science majors

    Science.gov (United States)

    Hill, Gary D.

    Two of the most important and difficult concepts in biology are photosynthesis and respiration. A pilot study was performed using student volunteers from introductory biology classes to assess student alternative frameworks regarding photosynthesis and respiration. The results of the pilot study were used to construct the Instrument for the Assessment of Respiration and Photosynthesis (IFARP). This was an 11-item, three-tier multiple choice instrument designed to conveniently assess the common misconceptions students have about these concepts upon entering a biology course. The first tier of each item of the IFARP contained a multiple choice question about photosynthesis or respiration. The second tier had a multiple choice question regarding the reason for the choice in the first tier. The third tier asked the students to indicate how confident they were in their responses, on a scale from 1 (not very confident) to 5 (very confident). The IFARP was administered as a pretest and posttest to a group of science non-majors in an introductory biology course. No significant changes were observed in student performance as measured by the IFARP between the pretest and posttest administrations. The students did, however, demonstrate a statistical increase in mean confidence levels regarding their knowledge of photosynthesis and respiration. Even though their comprehension and understanding regarding photosynthesis and respiration had not increased, the confidence they had in their responses about these two concepts had increased. The IFARP was also administered to a group of nursing student volunteers in an introductory microbiology course. This group of students also participated in the use of student-generated analogies as a learning strategy to alter conceptual frameworks. One test group of students provided analogies to photosynthesis and respiration, while the other test group provided analogies to two other concepts. No significant changes were observed in the

  7. Tracking diurnal changes of photosynthesis and evapotranspiration using fluorescence, gas exchange and hyperspectral remote sensing measurements

    Science.gov (United States)

    Wang, S.; Zhang, L.; Guanter, L.; Huang, C.

    2017-12-01

    Photosynthesis and evapotranspiration (ET) are the two most important activities of vegetation and make a great contribution to carbon, water and energy exchanges. Remote sensing provides opportunities for monitoring these processes across time and space. This study focuses on tracking diurnal changes of photosynthesis and evapotranspiration over soybean using multiple measurement techniques. Diurnal changes of both remote sensing-based indicators, including active and passive chlorophyll fluorescence and biophysical-related parameters, including photosynthesis rate (photo) and leaf stomatal conductance (cond), were observed. Results showed that both leaf-level steady-state fluorescence (Fs) and canopy-level solar-induced chlorophyll fluorescence were linearly correlated to photosynthetically active radiation (PAR) during the daytime. A double-peak diurnal change curve was observed for leaf-level photo and cond but not for Fs or SIF. Photo and cond showed a strong nonlinear (second-order) correlation, indicating that photosynthesis, which might be remotely sensed by SIF, has the opportunity to track short-term changes of ET. Results presented in this report will be helpful for better understanding the relationship between remote-sensing-based indices and vegetation's biophysical processes.

  8. Powered by light: Phototrophy and photosynthesis in prokaryotes and its evolution.

    Science.gov (United States)

    Nowicka, Beatrycze; Kruk, Jerzy

    2016-01-01

    Photosynthesis is a complex metabolic process enabling photosynthetic organisms to use solar energy for the reduction of carbon dioxide into biomass. This ancient pathway has revolutionized life on Earth. The most important event was the development of oxygenic photosynthesis. It had a tremendous impact on the Earth's geochemistry and the evolution of living beings, as the rise of atmospheric molecular oxygen enabled the development of a highly efficient aerobic metabolism, which later led to the evolution of complex multicellular organisms. The mechanism of photosynthesis has been the subject of intensive research and a great body of data has been accumulated. However, the evolution of this process is not fully understood, and the development of photosynthesis in prokaryota in particular remains an unresolved question. This review is devoted to the occurrence and main features of phototrophy and photosynthesis in prokaryotes. Hypotheses concerning the origin and spread of photosynthetic traits in bacteria are also discussed. Copyright © 2016 Elsevier GmbH. All rights reserved.

  9. The Path of Carbon in Photosynthesis VIII. The Role of Malic Acid

    Science.gov (United States)

    Bassham, James A.; Benson, Andrew A.; Calvin, Melvin

    1950-01-25

    Malonate has been found to inhibit the formation of malic acid during short periods of photosynthesis with radioactive carbon dioxide. This result, together with studies which show the photosynthetic cycle to be operating normally at the same time, indicates that malic acid is not an intermediate in photosynthesis but is probably closely related to some intermediate of the cycle. Absence of labeled succinic and fumaric acids in these experiments, in addition to the failure of malonate to inhibit photosynthesis, precludes the participation of these acids as intermediates in photosynthesis.

  10. Inorganic carbon availability in benthic diatom communities: photosynthesis and migration.

    Science.gov (United States)

    Marques da Silva, Jorge; Cruz, Sónia; Cartaxana, Paulo

    2017-09-05

    Diatom-dominated microphytobenthos (MPB) is the main primary producer of many intertidal and shallow subtidal environments, being therefore of critical importance to estuarine and coastal food webs. Owing to tidal cycles, intertidal MPB diatoms are subjected to environmental conditions far more variable than the ones experienced by pelagic diatoms (e.g. light, temperature, salinity, desiccation and nutrient availability). Nevertheless, benthic diatoms evolved adaptation mechanisms to these harsh conditions, including the capacity to move within steep physical and chemical gradients, allowing them to perform photosynthesis efficiently. In this contribution, we will review present knowledge on the effects of dissolved inorganic carbon (DIC) availability on photosynthesis and productivity of diatom-dominated MPB. We present evidence of carbon limitation of photosynthesis in benthic diatom mats and highly productive MPB natural communities. Furthermore, we hypothesize that active vertical migration of epipelic motile diatoms could overcome local depletion of DIC in the photic layer, providing the cells alternately with light and inorganic carbon supply. The few available longer-term experiments on the effects of inorganic carbon enrichment on the productivity of diatom-dominated MPB have yielded inconsistent results. Therefore, further studies are needed to properly assess the response of MPB communities to increased CO 2 and ocean acidification related to climate change.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'. © 2017 The Author(s).

  11. Enhanced Thermostability of Arabidopsis Rubisco activase improves photosynthesis and growth rates under moderate heat stress.

    Science.gov (United States)

    Kurek, Itzhak; Chang, Thom Kai; Bertain, Sean M; Madrigal, Alfredo; Liu, Lu; Lassner, Michael W; Zhu, Genhai

    2007-10-01

    Plant photosynthesis declines when the temperature exceeds its optimum range. Recent evidence indicates that the reduction in photosynthesis is linked to ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) deactivation due to the inhibition of Rubisco activase (RCA) under moderately elevated temperatures. To test the hypothesis that thermostable RCA can improve photosynthesis under elevated temperatures, we used gene shuffling technology to generate several Arabidopsis thaliana RCA1 (short isoform) variants exhibiting improved thermostability. Wild-type RCA1 and selected thermostable RCA1 variants were introduced into an Arabidopsis RCA deletion (Deltarca) line. In a long-term growth test at either constant 26 degrees C or daily 4-h 30 degrees C exposure, the transgenic lines with the thermostable RCA1 variants exhibited higher photosynthetic rates, improved development patterns, higher biomass, and increased seed yields compared with the lines expressing wild-type RCA1 and a slight improvement compared with untransformed Arabidopsis plants. These results provide clear evidence that RCA is a major limiting factor in plant photosynthesis under moderately elevated temperatures and a potential target for genetic manipulation to improve crop plants productivity under heat stress conditions.

  12. Exploring Photosynthesis and Plant Stress Using Inexpensive Chlorophyll Fluorometers

    Science.gov (United States)

    Cessna, Stephen; Demmig-Adams, Barbara; Adams, William W., III

    2010-01-01

    Mastering the concept of photosynthesis is of critical importance to learning plant physiology and its applications, but seems to be one of the more challenging concepts in biology. This teaching challenge is no doubt compounded by the complexity by which plants alter photosynthesis in different environments. Here we suggest the use of chlorophyll…

  13. Reevaluation of the plant “gemstones”: Calcium oxalate crystals sustain photosynthesis under drought conditions

    Science.gov (United States)

    Tooulakou, Georgia; Giannopoulos, Andreas; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Dotsika, Elissavet; Orkoula, Malvina G.; Kontoyannis, Christos G.; Fasseas, Costas; Liakopoulos, Georgios; Klapa, Maria I.; Karabourniotis, George

    2016-01-01

    ABSTRACT Land plants face the perpetual dilemma of using atmospheric carbon dioxide for photosynthesis and losing water vapors, or saving water and reducing photosynthesis and thus growth. The reason behind this dilemma is that this simultaneous exchange of gases is accomplished through the same minute pores on leaf surfaces, called stomata. In a recent study we provided evidence that pigweed, an aggressive weed, attenuates this problem exploiting large crystals of calcium oxalate as dynamic carbon pools. This plant is able to photosynthesize even under drought conditions, when stomata are closed and water losses are limited, using carbon dioxide from crystal decomposition instead from the atmosphere. Abscisic acid, an alarm signal that causes stomatal closure seems to be implicated in this function and for this reason we named this path “alarm photosynthesis.” The so-far “enigmatic,” but highly conserved and widespread among plant species calcium oxalate crystals seem to play a crucial role in the survival of plants. PMID:27471886

  14. On the relation between phototaxis and photosynthesis in Rhodospirillum Rubrum

    NARCIS (Netherlands)

    Thomas, J.B.; Nijenhuis, L.E.

    1950-01-01

    The relation between phototaxis and photosynthesis in Rhodospirillum rubrum has been studied. The light intensity at which saturation is reached in photosynthesis proved to coincide with that at which the contrast sensitivity starts to decrease. Potassium cyanide, which preferably inhibits the

  15. The Brave New World of GEC Evaluation: The Experience of the Rhode Island Geriatric Education Center

    Science.gov (United States)

    Filinson, Rachel; Clark, Phillip G.; Evans, Joann; Padula, Cynthia; Willey, Cynthia

    2012-01-01

    In 2007, the Health Resources Services Administration introduced new mandates that raised the standards on program evaluation for Geriatric Education Centers. Described in this article are the primary and secondary evaluation efforts undertaken for one program within the Rhode Island Geriatric Education Center (RIGEC), the findings from these…

  16. Particle-bound metal transport after removal of a small dam in the Pawtuxet River, Rhode Island, USA

    Science.gov (United States)

    The Pawtuxet River in Rhode Island, USA, has a long history of industrial activity and pollutant discharges. Metal contamination of the river sediments is well documented and historically exceeded toxicity thresholds for a variety of organisms. The Pawtuxet River dam, a low-head ...

  17. Photosynthesis-fermentation hybrid system to produce lipid feedstock for algal biofuel.

    Science.gov (United States)

    Lu, Yue; Dai, Junbiao; Wu, Qingyu

    2013-01-01

    To avoid bacterial contamination due to medium replacement in the expanded application of a photosynthesis-fermentation model, an integrated photosynthesis-fermentation hybrid system was set up and evaluated for algal lipid production using Chlorella protothecoides. In this system, the CO2-rich off-gas from the fermentation process was recycled to agitate medium in thephotobioreactor, which could provide initial cells for the heterotrophic fermentation. The cell concentration reached 1.03 +/- 0.07 g/L during photoautotrophic growth and then the concentrated green cells were switched to heterotrophic fermentation after removing over 99.5% ofnitrogen in the medium by a nitrogen removal device. At the end offermentation in the system, the cell concentration could reach as high as 100.51 +/- 2.03 g/L, and 60.05 +/- 1.38% lipid content was achieved simultaneously. The lipid yield (60.36 +/- 2.63 g/L) in the hybrid system was over 700 times higher than that in a photobioreactor and exceeded that by fermentation alone (47.56 +/- 7.31 g/L). The developed photosynthesis-fermentation hybrid system in this study was not only a feasible option to enhance microalgal lipid production, but also an environment-friendly approach to produce biofuel feedstock through concurrent utilization of ammonia nitrogen, CO2, and organic carbons.

  18. The primary steps of photosynthesis

    International Nuclear Information System (INIS)

    Fleming, G.R.; Van Grondelle, R.

    1996-01-01

    The two important initial steps of photosynthesis-electron transfer and energy transfer occur with great speed and efficiency. New techniques in laser optics and genetic engineering age helping us to understand why. (author). 24 refs. 8 figs

  19. Adolescent suicide and health risk behaviors: Rhode Island's 2007 Youth Risk Behavior Survey.

    Science.gov (United States)

    Jiang, Yongwen; Perry, Donald K; Hesser, Jana E

    2010-05-01

    Suicide is the third-leading cause of death among high school students in the U.S. This study examined the relationships among indicators of depressed mood, suicidal thoughts, suicide attempts, and demographics and risk behaviors in Rhode Island high school students. Data from Rhode Island's 2007 Youth Risk Behavior Survey were utilized for this study. The statewide sample contained 2210 randomly selected public high school students. Data were analyzed in 2008 to model for each of five depressed mood/suicide indicators using multivariable logistic regression. By examining depressed mood and suicide indicators through a multivariable approach, the strongest predictors were identified, for multiple as well as specific suicide indicators. These predictors included being female, having low grades, speaking a language other than English at home, being lesbian/gay/bisexual/unsure of sexual orientation, not going to school as a result of feeling unsafe, having been a victim of forced sexual intercourse, being a current cigarette smoker, and having a self-perception of being overweight. The strength of associations between three factors (immigrant status, feeling unsafe, and having forced sex) and suicide indicators adds new information about potential predictors of suicidal behavior in adolescents. 2010 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  20. Impact of the ion transportome of chloroplasts on the optimization of photosynthesis.

    Science.gov (United States)

    Szabò, Ildikò; Spetea, Cornelia

    2017-06-01

    Ions play fundamental roles in all living cells, and their gradients are often essential to fuel transport, regulate enzyme activities, and transduce energy within cells. Regulation of their homeostasis is essential for cell metabolism. Recent results indicate that modulation of ion fluxes might also represent a useful strategy to regulate one of the most important physiological processes taking place in chloroplasts, photosynthesis. Photosynthesis is highly regulated, due to its unique role as a cellular engine for growth in the light. Controlling the balance between ATP and NADPH synthesis is a critical task, and availability of these molecules can limit the overall photosynthetic yield. Photosynthetic organisms optimize photosynthesis in low light, where excitation energy limits CO2 fixation, and minimize photo-oxidative damage in high light by dissipating excess photons. Despite extensive studies of these phenomena, the mechanism governing light utilization in plants is still poorly understood. In this review, we provide an update of the recently identified chloroplast-located ion channels and transporters whose function impacts photosynthetic efficiency in plants. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. Quantum design of photosynthesis for bio-inspired solar-energy conversion

    NARCIS (Netherlands)

    Romero, Elisabet; Novoderezhkin, Vladimir I.; van Grondelle, Rienk

    2017-01-01

    Photosynthesis is the natural process that converts solar photons into energy-rich products that are needed to drive the biochemistry of life. Two ultrafast processes form the basis of photosynthesis: excitation energy transfer and charge separation. Under optimal conditions, every photon that is

  2. [Photosynthesis and transpiration characteristics of female and male Trichosanthes kirilowii Maxim individuals].

    Science.gov (United States)

    Liu, Yun; Zhong, Zhang-cheng; Wang, Xiao-xue; Xie, Jun; Yang, Wen-ying

    2011-03-01

    A field research was conducted on the photosynthesis and transpiration characteristics of dioecious Trichosanthes kirilowii individuals at four key development stages. At vegetative growth stage, the photosynthesis rate, transpiration rate, stomatal conductance, and water use efficiency of male individuals were higher than those of female individuals, and hence, male individuals entered into reproductive growth stage 22 days earlier than female individuals. After entering into reproductive growth stage, male individuals had higher photosynthesis rate, transpiration rate, and stomatal conductance, but slightly lower water use efficiency than female individuals. As the female individuals started to reproductive growth, their photosynthesis rate and water use efficiency were significantly lower, while the transpiration rate and stomatal conductance were higher than those of the male individuals. The effects of climate factors on the growth and development of T. kirilowii mainly occurred at its vegetative growth and early reproductive growth stages, and weakened at later reproductive growth stages. Higher temperature and lower relative humidity benefited the growth and development of T. kirilowii, and illumination could enhance the photosynthesis rate of T. kirilowii, especially its male individuals. After entering into reproductive growth stage, the photosynthesis rate of male individuals increased significantly with increasing illumination, but that of female individuals only had a slight increase, and the transpiration rate of male individuals as well as the photosynthesis rate of female individuals all increased significantly with increasing temperature.

  3. 75 FR 57188 - Rhode Island: Final Authorization of State Hazardous Waste Management Program Revisions

    Science.gov (United States)

    2010-09-20

    ... implementation of the Land Disposal Restrictions (LDR) requirements in 40 CFR part 268 because Rhode Island has..., April 24, 2006 (other than LDR requirements): Rules 2.2 C, 2.2 C.4, 2.2 F, 2.2 G, 2.2 I, 2.2 J, 7.0 B.82...)), but Safe Food and Fertilizer disagrees with the EPA determinations and states that the ``use of...

  4. Cyanobacterial photosynthesis under sulfidic conditions: insights from the isolate Leptolyngbya sp. strain hensonii

    Science.gov (United States)

    Hamilton, Trinity L; Klatt, Judith M; de Beer, Dirk; Macalady, Jennifer L

    2018-01-01

    We report the isolation of a pinnacle-forming cyanobacterium isolated from a microbial mat covering the sediment surface at Little Salt Spring—a flooded sinkhole in Florida with a perennially microoxic and sulfidic water column. The draft genome of the isolate encodes all of the enzymatic machinery necessary for both oxygenic and anoxygenic photosynthesis, as well as genes for methylating hopanoids at the C-2 position. The physiological response of the isolate to H2S is complex: (i) no induction time is necessary for anoxygenic photosynthesis; (ii) rates of anoxygenic photosynthesis are regulated by both H2S and irradiance; (iii) O2 production is inhibited by H2S concentrations as low as 1 μM and the recovery rate of oxygenic photosynthesis is dependent on irradiance; (iv) under the optimal light conditions for oxygenic photosynthesis, rates of anoxygenic photosynthesis are nearly double those of oxygenic photosynthesis. We hypothesize that the specific adaptation mechanisms of the isolate to H2S emerged from a close spatial interaction with sulfate-reducing bacteria. The new isolate, Leptolyngbya sp. strain hensonii, is not closely related to other well-characterized Cyanobacteria that can perform anoxygenic photosynthesis, which further highlights the need to characterize the diversity and biogeography of metabolically versatile Cyanobacteria. The isolate will be an ideal model organism for exploring the adaptation of Cyanobacteria to sulfidic conditions. PMID:29328062

  5. Cyanobacterial photosynthesis under sulfidic conditions: insights from the isolate Leptolyngbya sp. strain hensonii.

    Science.gov (United States)

    Hamilton, Trinity L; Klatt, Judith M; de Beer, Dirk; Macalady, Jennifer L

    2018-02-01

    We report the isolation of a pinnacle-forming cyanobacterium isolated from a microbial mat covering the sediment surface at Little Salt Spring-a flooded sinkhole in Florida with a perennially microoxic and sulfidic water column. The draft genome of the isolate encodes all of the enzymatic machinery necessary for both oxygenic and anoxygenic photosynthesis, as well as genes for methylating hopanoids at the C-2 position. The physiological response of the isolate to H 2 S is complex: (i) no induction time is necessary for anoxygenic photosynthesis; (ii) rates of anoxygenic photosynthesis are regulated by both H 2 S and irradiance; (iii) O 2 production is inhibited by H 2 S concentrations as low as 1 μM and the recovery rate of oxygenic photosynthesis is dependent on irradiance; (iv) under the optimal light conditions for oxygenic photosynthesis, rates of anoxygenic photosynthesis are nearly double those of oxygenic photosynthesis. We hypothesize that the specific adaptation mechanisms of the isolate to H 2 S emerged from a close spatial interaction with sulfate-reducing bacteria. The new isolate, Leptolyngbya sp. strain hensonii, is not closely related to other well-characterized Cyanobacteria that can perform anoxygenic photosynthesis, which further highlights the need to characterize the diversity and biogeography of metabolically versatile Cyanobacteria. The isolate will be an ideal model organism for exploring the adaptation of Cyanobacteria to sulfidic conditions.

  6. How Will Teachers Fare in Rhode Island's New Hybrid Pension Plan? Public Pension Project Brief 4

    Science.gov (United States)

    Johnson, Richard W.; Butrica, Barbara A.; Haaga, Owen; Southgate, Benjamin G.

    2014-01-01

    Hybrid retirement plans that combine defined benefit pensions with 401(k) type, defined contribution accounts can play important roles in the reform of public-sector pensions. Summarizing results from our longer report ["How Will Rhode Island's New Hybrid Pension Plan Affect Teachers? A Report of the Public Pension Project" (2014)], this…

  7. 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

  8. From molecules to materials pathways to artificial photosynthesis

    CERN Document Server

    Rozhkova, Elena A

    2015-01-01

    This interdisciplinary book focuses on the various aspects transformation of the energy from sunlight into the chemical bonds of a fuel, known as the artificial photosynthesis, and addresses the emergent challenges connected with growing societal demands for clean and sustainable energy technologies. The editors assemble the research of world-recognized experts in the field of both molecular and materials artificial systems for energy production. Contributors cover the full scope of research on photosynthesis and related energy processes.

  9. A mixed incoherent feed-forward loop contributes to the regulation of bacterial photosynthesis genes.

    Science.gov (United States)

    Mank, Nils N; Berghoff, Bork A; Klug, Gabriele

    2013-03-01

    Living cells use a variety of regulatory network motifs for accurate gene expression in response to changes in their environment or during differentiation processes. In Rhodobacter sphaeroides, a complex regulatory network controls expression of photosynthesis genes to guarantee optimal energy supply on one hand and to avoid photooxidative stress on the other hand. Recently, we identified a mixed incoherent feed-forward loop comprising the transcription factor PrrA, the sRNA PcrZ and photosynthesis target genes as part of this regulatory network. This point-of-view provides a comparison to other described feed-forward loops and discusses the physiological relevance of PcrZ in more detail.

  10. The pineapple genome and the evolution of CAM photosynthesis.

    Science.gov (United States)

    Ming, Ray; VanBuren, Robert; Wai, Ching Man; Tang, Haibao; Schatz, Michael C; Bowers, John E; Lyons, Eric; Wang, Ming-Li; Chen, Jung; Biggers, Eric; Zhang, Jisen; Huang, Lixian; Zhang, Lingmao; Miao, Wenjing; Zhang, Jian; Ye, Zhangyao; Miao, Chenyong; Lin, Zhicong; Wang, Hao; Zhou, Hongye; Yim, Won C; Priest, Henry D; Zheng, Chunfang; Woodhouse, Margaret; Edger, Patrick P; Guyot, Romain; Guo, Hao-Bo; Guo, Hong; Zheng, Guangyong; Singh, Ratnesh; Sharma, Anupma; Min, Xiangjia; Zheng, Yun; Lee, Hayan; Gurtowski, James; Sedlazeck, Fritz J; Harkess, Alex; McKain, Michael R; Liao, Zhenyang; Fang, Jingping; Liu, Juan; Zhang, Xiaodan; Zhang, Qing; Hu, Weichang; Qin, Yuan; Wang, Kai; Chen, Li-Yu; Shirley, Neil; Lin, Yann-Rong; Liu, Li-Yu; Hernandez, Alvaro G; Wright, Chris L; Bulone, Vincent; Tuskan, Gerald A; Heath, Katy; Zee, Francis; Moore, Paul H; Sunkar, Ramanjulu; Leebens-Mack, James H; Mockler, Todd; Bennetzen, Jeffrey L; Freeling, Michael; Sankoff, David; Paterson, Andrew H; Zhu, Xinguang; Yang, Xiaohan; Smith, J Andrew C; Cushman, John C; Paull, Robert E; Yu, Qingyi

    2015-12-01

    Pineapple (Ananas comosus (L.) Merr.) is the most economically valuable crop possessing crassulacean acid metabolism (CAM), a photosynthetic carbon assimilation pathway with high water-use efficiency, and the second most important tropical fruit. We sequenced the genomes of pineapple varieties F153 and MD2 and a wild pineapple relative, Ananas bracteatus accession CB5. The pineapple genome has one fewer ancient whole-genome duplication event than sequenced grass genomes and a conserved karyotype with seven chromosomes from before the ρ duplication event. The pineapple lineage has transitioned from C3 photosynthesis to CAM, with CAM-related genes exhibiting a diel expression pattern in photosynthetic tissues. CAM pathway genes were enriched with cis-regulatory elements associated with the regulation of circadian clock genes, providing the first cis-regulatory link between CAM and circadian clock regulation. Pineapple CAM photosynthesis evolved by the reconfiguration of pathways in C3 plants, through the regulatory neofunctionalization of preexisting genes and not through the acquisition of neofunctionalized genes via whole-genome or tandem gene duplication.

  11. Photosynthesis-dependent H2O2 transfer from chloroplasts to nuclei provides a high-light signalling mechanism.

    Science.gov (United States)

    Exposito-Rodriguez, Marino; Laissue, Pierre Philippe; Yvon-Durocher, Gabriel; Smirnoff, Nicholas; Mullineaux, Philip M

    2017-06-29

    Chloroplasts communicate information by signalling to nuclei during acclimation to fluctuating light. Several potential operating signals originating from chloroplasts have been proposed, but none have been shown to move to nuclei to modulate gene expression. One proposed signal is hydrogen peroxide (H 2 O 2 ) produced by chloroplasts in a light-dependent manner. Using HyPer2, a genetically encoded fluorescent H 2 O 2 sensor, we show that in photosynthetic Nicotiana benthamiana epidermal cells, exposure to high light increases H 2 O 2 production in chloroplast stroma, cytosol and nuclei. Critically, over-expression of stromal ascorbate peroxidase (H 2 O 2 scavenger) or treatment with DCMU (photosynthesis inhibitor) attenuates nuclear H 2 O 2 accumulation and high light-responsive gene expression. Cytosolic ascorbate peroxidase over-expression has little effect on nuclear H 2 O 2 accumulation and high light-responsive gene expression. This is because the H 2 O 2 derives from a sub-population of chloroplasts closely associated with nuclei. Therefore, direct H 2 O 2 transfer from chloroplasts to nuclei, avoiding the cytosol, enables photosynthetic control over gene expression.Multiple plastid-derived signals have been proposed but not shown to move to the nucleus to promote plant acclimation to fluctuating light. Here the authors use a fluorescent hydrogen peroxide sensor to provide evidence that H 2 O 2 is transferred directly from chloroplasts to nuclei to control nuclear gene expression.

  12. Novel Genetic Tools to Accelerate Our Understanding of Photosynthesis and Lipid Accumulation

    Science.gov (United States)

    2014-08-20

    understanding of photosynthesis and lipid accumulation Martin C. Jonikas, Ph.D. Carnegie Institution for Science, Department of Plant Biology 260...knowledge of algal lipid metabolism and photosynthesis . Advances in our basic understanding of these processes will facilitate genetic engineering of...algae to improve lipid yields. Currently, one of the greatest roadblocks in the study of algal photosynthesis and lipid metabolism is the slow pace of

  13. Enhanced Thermostability of Arabidopsis Rubisco Activase Improves Photosynthesis and Growth Rates under Moderate Heat Stress[OA

    Science.gov (United States)

    Kurek, Itzhak; Chang, Thom Kai; Bertain, Sean M.; Madrigal, Alfredo; Liu, Lu; Lassner, Michael W.; Zhu, Genhai

    2007-01-01

    Plant photosynthesis declines when the temperature exceeds its optimum range. Recent evidence indicates that the reduction in photosynthesis is linked to ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) deactivation due to the inhibition of Rubisco activase (RCA) under moderately elevated temperatures. To test the hypothesis that thermostable RCA can improve photosynthesis under elevated temperatures, we used gene shuffling technology to generate several Arabidopsis thaliana RCA1 (short isoform) variants exhibiting improved thermostability. Wild-type RCA1 and selected thermostable RCA1 variants were introduced into an Arabidopsis RCA deletion (Δrca) line. In a long-term growth test at either constant 26°C or daily 4-h 30°C exposure, the transgenic lines with the thermostable RCA1 variants exhibited higher photosynthetic rates, improved development patterns, higher biomass, and increased seed yields compared with the lines expressing wild-type RCA1 and a slight improvement compared with untransformed Arabidopsis plants. These results provide clear evidence that RCA is a major limiting factor in plant photosynthesis under moderately elevated temperatures and a potential target for genetic manipulation to improve crop plants productivity under heat stress conditions. PMID:17933901

  14. Global artificial photosynthesis project: a scientific and legal introduction.

    Science.gov (United States)

    Faunce, Thomas

    2011-12-01

    With the global human population set to exceed 10 billion by 2050, its collective energy consumption to rise from 400 to over 500 EJ/yr and with the natural environment under increasing pressure from these sources as well as from anthropogenic climate change, political solutions such as the creation of an efficient carbon price and trading scheme may arrive too late. In this context, the scientific community is exploring technological remedies. Central to these options is artificial photosynthesis--the creation, particularly through nanotechnology, of devices capable to doing what plants have done for millions of years - transforming sunlight, water and carbon dioxide into food and fuel. This article argues that a Global Artificial Photosynthesis (GAP) project can raise the public profile and encourage the pace, complexity and funding of scientific collaborations in artificial photosynthesis research. The legal structure of a GAP project will be critical to prevent issues such as state sovereignty over energy and food resources and corporate intellectual monopoly privileges unduly inhibiting the important contribution of artificial photosynthesis to global public health and environmental sustainability. The article presents an introduction to the scientific and legal concepts behind a GAP project.

  15. Growth, water relations and photosynthesis of seedlings and resprouts after fire

    Science.gov (United States)

    Clemente, Adelaide S.; Rego, Francisco C.; Correia, Otília A.

    2005-05-01

    Seasonal patterns of growth, water relations, photosynthesis and leaf characteristics were compared between obligate seeders ( Cistus monspeliensis and Cistus ladanifer) and resprouters ( Arbutus unedo and Pistacia lentiscus) from the first to the second year after fire. We hypothesized that seedlings would be more water-limited than resprouts due to their shallower root systems. Regarding water use strategies, Cistus species are drought semi-deciduous and A. unedo and P. lentiscus are evergreen sclerophylls, therefore, comparisons were based on the relative deviation from mature conspecific plants. Seedlings and resprouts had higher shoot elongation and leaf production than mature plants, and over an extended period. Differences from mature plants were larger in resprouts, with two-fold transpiration, leaf conductance and photosynthesis in late spring/early summer. Seedlings of C. monspeliensis exhibited higher transpiration and leaf conductance than mature plants, while those of C. ladanifer only exhibited higher water potential. Growth increments and ameliorated water relations and photosynthesis after fire were attributed to an increase in water and nutrient availability. The small differences in water relations and photosynthesis between seedlings and mature conspecifics are in accordance with the prediction of seedlings experiencing higher water limitation than resprouts. We attribute these results to differences in root systems: resprouters benefited from an increase in root/shoot ratios and the presence of deep roots whereas Cistus seedlings relied on very shallow roots, which cannot provide assess to deep water during summer. Nevertheless, seedlings did not show evidence of experiencing a more severe water limitation than mature conspecifics, which we attributed to the presence of efficient mechanisms of avoiding and tolerating water stress. The results are discussed in relation to post-fire demography of seeders and resprouters in Mediterranean

  16. A list of personal perspectives with selected quotations, along with lists of tributes, historical notes, Nobel and Kettering awards related to photosynthesis.

    Science.gov (United States)

    Krogmann, David W

    2002-01-01

    The history of photosynthesis research can be found in original papers and books. However, a special history is available from the prefatory chapters and the personal perspectives of various researchers who published them in several journals over the last 40 years. We have compiled a list of such perspectives published since 1964. Selection is not easy, especially of authors who were not directly engaged in photosynthesis research; some are included for their special insights related to central issues in the study of photosynthesis. Our journal, Photosynthesis Research, contains other valuable historic data in the occasional tributes, obituaries and historical notes, that have been published. Lists of these items are included. This article ends by listing the Nobel prizes related to photosynthesis and the Kettering Awards for Excellence in Photosynthesis Research. Wherever possible, a web page address is provided. The web page addresses have been taken from the article 'Photosynthesis and the Web: 2001' by Larry Orr and Govindjee, available at http://www.life.uiuc.edu/govindjee/photoweb and at http://photoscience.la.asu.edu/photosyn/ photoweb/default.html.When I find a bit of leisureI trifle with my papers.This is one of the lesserfrailities.'- Horace, Satires I, IV.

  17. Application of microbial photosynthesis to energy production and CO2 fixation

    International Nuclear Information System (INIS)

    Asada, Y.; Miyake, J.

    1994-01-01

    This paper presents different applications of microbial photosynthesis for energy production and carbon dioxide fixation. The authors discuss about energetic aspects of photosynthesis and features of biological way for solar energy conversion. (TEC). 4 figs., 12 refs

  18. Vegetation Function and Physiology: Photosynthesis, Fluorescence and Non-photochemical Quenching (NPQ)

    Science.gov (United States)

    Zhang, Q.; Yao, T.

    2017-12-01

    Photosynthesis is a basic physiological function of vegetation that relies on PAR provided through photosynthetic pigments (mainly chlorophyll) for plant growth and biomass accumulation. Vegetation chlorophyll (chl) content and non-chlorophyll (non-chl) components vary with plant functional types (PFTs) and growing stages. The PAR absorbed by canopy chlorophyll (APARchl) is associated with photosynthesis (i.e., gross primary production, GPP) while the PAR absorbed by canopy non-chl components (APARnon-chl) is not associated with photosynthesis. Under non-optimal environmental conditions, vegetation is "stressed" and both photosynthesis (GPP) and light use efficiency are reduced, therefore, excess portions of APARchl are discarded as fluorescence or non-photochemical quenching (NPQ). The photochemical reflectance index (PRI) is a measurement related to NPQ. Both PRI and yield of solar induced chlorophyll fluorescence (SIFyield = SIF/APARchl) have been proposed as possible bio-indicators of LUEchl. We have successfully developed an algorithm to distinguish between chlorophyll and non-chl components of vegetation, and to retrieve fractional absorptions of PAR by chlorophyll (fAPARchl) and by non-chl components (fAPARnon-chl) with surface reflectance of MODIS bands 1 - 7. A method originally pioneered by Hanan et al. (2002) has been used to retrieve fAPAR for vegetation photosynthesis (fAPARPSN) at flux tower sites based on the light response curve of tower net ecosystem exchange (NEE) and incident PAR at low light intensity. We have also retrieved the PRI from MODIS data (bands 11 and 1) and have derived SIFyield with the Global Ozone Monitoring Experiment - 2 (GOME-2) SIF data. We find that fAPARPSN at flux tower sites matches well with site fAPARchl, and ratio fAPARnon-chl/fAPARchl varies largely. APARchl can explain >=78% variation in seasonal GPP . We disentangle the possible impact of fAPARchl on PRI from physiological stress response, disentangle the possible

  19. Photosynthesis

    DEFF Research Database (Denmark)

    Pribil, Mathias; Leister, Dario Michael

    2017-01-01

    on the genetic engineering of developmental or bioenergetic processes, such as photosynthesis. These approaches offer the prospect of a renewal of the Green Revolution, which is urgently required tomeet the continuously increasing demand for superior high-yield crop varieties for human sustenance and industrial...... by exponential population growth and increased demand for crop plants as sources of renewable energy or high-value products. The foreseeable intensification of competition between agronomical and industrial use makes it imperative that the available supply of cropland be used more efficiently. During the Green...... Revolution that began in the 1960s, significant increases in yield could be achieved by more effective farming strategies, innovations in fertilization, and the introduction of dwarfing genes into important crop species like rice (Oryza sativa) and wheat (Triticum aestivum). The last resulted in a shift...

  20. Character, distribution, and ecological significance of storm wave-induced scour in Rhode Island Sound, USA

    Science.gov (United States)

    McMullen, Katherine Y.; Poppe, Lawrence J.; Parker, Castle E.

    2015-01-01

    Multibeam bathymetry, collected during NOAA hydrographic surveys in 2008 and 2009, is coupled with USGS data from sampling and photographic stations to map the seabed morphology and composition of Rhode Island Sound along the US Atlantic coast, and to provide information on sediment transport and benthic habitats. Patchworks of scour depressions cover large areas on seaward-facing slopes and bathymetric highs in the sound. These depressions average 0.5-0.8 m deep and occur in water depths reaching as much as 42 m. They have relatively steep well-defined sides and coarser-grained floors, and vary strongly in shape, size, and configuration. Some individual scour depressions have apparently expanded to combine with adjacent depressions, forming larger eroded areas that commonly contain outliers of the original seafloor sediments. Where cobbles and scattered boulders are present on the depression floors, the muddy Holocene sands have been completely removed and the winnowed relict Pleistocene deposits exposed. Low tidal-current velocities and the lack of obstacle marks suggest that bidirectional tidal currents alone are not capable of forming these features. These depressions are formed and maintained under high-energy shelf conditions owing to repetitive cyclic loading imposed by high-amplitude, long-period, storm-driven waves that reduce the effective shear strength of the sediment, cause resuspension, and expose the suspended sediments to erosion by wind-driven and tidal currents. Because epifauna dominate on gravel floors of the depressions and infauna are prevalent in the finer-grained Holocene deposits, it is concluded that the resultant close juxtaposition of silty sand-, sand-, and gravel-dependent communities promotes regional faunal complexity. These findings expand on earlier interpretations, documenting how storm wave-induced scour produces sorted bedforms that control much of the benthic geologic and biologic diversity in Rhode Island Sound.

  1. The role of carbonic anhydrase in C4 photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Studer, Anthony [Life Sciences Research Foundation, Baltimore, MD (United States)

    2015-10-01

    Current pressures on the global food supply have accelerated the urgency for a second green revolution using novel and sustainable approaches to increase crop yield and efficiency. This proposal outlines experiments to address fundamental questions regarding the biology of C4 photosynthesis, the method of carbon fixation utilized by the most productive food, feed and bioenergy crops. Carbonic anhydrase (CA) has been implicated in multiple cellular functions including nitrogen metabolism, water use efficiency, and photosynthesis. CA catalyzes the first dedicated step in C4 photosynthesis, the hydration of CO2 into bicarbonate, and is potentially rate limiting in C4 grasses. Using insertional mutagenesis, we have generated CA mutants in maize, and propose the characterization of these mutants using phenotypic, physiological, and transcriptomic profiling to assay the plant’s response to altered CA activity. In addition, florescent protein tagging experiments will be employed to study the subcellular localization of CA paralogs, providing critical data for modeling carbon fixation in C4 plants. Finally, I propose parallel experiments in Setaria viridis to explore its relevance as model C4 grass. Using a multifaceted approach, this proposal addresses important questions in basic biology, as well as the need for translation research in response to looming global food challenges.

  2. NDH-Mediated Cyclic Electron Flow Around Photosystem I is Crucial for C4 Photosynthesis.

    Science.gov (United States)

    Ishikawa, Noriko; Takabayashi, Atsushi; Noguchi, Ko; Tazoe, Youshi; Yamamoto, Hiroshi; von Caemmerer, Susanne; Sato, Fumihiko; Endo, Tsuyoshi

    2016-10-01

    C 4 photosynthesis exhibits efficient CO 2 assimilation in ambient air by concentrating CO 2 around ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) through a metabolic pathway called the C 4 cycle. It has been suggested that cyclic electron flow (CEF) around PSI mediated by chloroplast NADH dehydrogenase-like complex (NDH), an alternative pathway of photosynthetic electron transport (PET), plays a crucial role in C 4 photosynthesis, although the contribution of NDH-mediated CEF is small in C 3 photosynthesis. Here, we generated NDH-suppressed transformants of a C 4 plant, Flaveria bidentis, and showed that the NDH-suppressed plants grow poorly, especially under low-light conditions. CO 2 assimilation rates were consistently decreased in the NDH-suppressed plants under low and medium light intensities. Measurements of non-photochemical quenching (NPQ) of Chl fluorescence, the oxidation state of the reaction center of PSI (P700) and the electrochromic shift (ECS) of pigment absorbance indicated that proton translocation across the thylakoid membrane is impaired in the NDH-suppressed plants. Since proton translocation across the thylakoid membrane induces ATP production, these results suggest that NDH-mediated CEF plays a role in the supply of ATP which is required for C 4 photosynthesis. Such a role is more crucial when the light that is available for photosynthesis is limited and the energy production by PET becomes rate-determining for C 4 photosynthesis. Our results demonstrate that the physiological contribution of NDH-mediated CEF is greater in C 4 photosynthesis than in C 3 photosynthesis, suggesting that the mechanism of PET in C 4 photosynthesis has changed from that in C 3 photosynthesis accompanying the changes in the mechanism of CO 2 assimilation. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  3. Growth and photosynthesis of lettuce

    NARCIS (Netherlands)

    Holsteijn, van H.M.C.

    1981-01-01

    Butterhead lettuce is an important glass-house crop in the poor light period in The Netherlands. Fundamental data about the influence of temperature, light and CO 2 on growth and photosynthesis are important e.g. to facilitate selection criteria for new cultivars. In

  4. Assessing Photosynthesis by Fluorescence Imaging

    Science.gov (United States)

    Saura, Pedro; Quiles, Maria Jose

    2011-01-01

    This practical paper describes a novel fluorescence imaging experiment to study the three processes of photochemistry, fluorescence and thermal energy dissipation, which compete during the dissipation of excitation energy in photosynthesis. The technique represents a non-invasive tool for revealing and understanding the spatial heterogeneity in…

  5. Inhibition of apparent photosynthesis by nitrogen oxides

    Energy Technology Data Exchange (ETDEWEB)

    Hill, A C; Bennett, J H

    1970-01-01

    The nitrogen oxides (NO/sub 2/ and NO) inhibited apparent photosynthesis of oats and alfalfa at concentrations below those required to cause visible injury. There appeared to be a threshold concentration of about 0.6 ppm for each pollutant. An additive effect in depressing apparent photosynthesis occurred when the plants were exposed to a mixture of NO and NO/sub 2/. Although NO produced a more rapid effect on the plants, lower concentrations of NO/sub 2/ were required to cause a given inhibition after 2 hour of exposure. Inhibition by nitric oxide was more closely related to its partial pressure than was inhibition by NO/sub 2/.

  6. Photosynthesis: From De Saussure To Liebig.

    Science.gov (United States)

    Pennazio, Sergio

    2017-01-01

    The dawn of photosynthesis, characterized by the research of Priestley, Ingen- Housz and Senebier, culminated in 1804 with a historical essay of Théodore De Saussure. According to the historians, during the first half of the nineteenth century in which the genesis of the cell theory started off, the research on photosynthesis met a phase of stagnation. Indeed, the literature review of the period does not report particular innovation; however, several scientists (botanists, physiologists, and chemists) supported the thesis of De Saussure with a series of analyses that, in our opinion, deserve to be known. Mirbel, De Candolle, Raspail, Berzelius, Payen, Dutrochet, von Mohl, and other scholars attempted to expand knowledge on photosynthesis but were not able to arrive at a theory that was consistent with a functional mechanism, nor with a suitable chemical model to explain the transformation of the water and carbon dioxide into sugars. A classic case of such inadequacy concerns the discovery of chlorophyll. This compound, isolated in 1818 by Pelletier and Caventou, remained an enigma for many years and was never put in relation with the synthesis of starch. The accurate research of von Mohl led this scientist to believe that the granules of chlorophyll were entirely independent of starch granules, although in many cases these latter were observable inside the granules of chlorophyll. Only in the early forties, Justus von Liebig realized that the assimilation of carbon and hydrogen required a series of chemical reactions that, starting from some organic acids, ended in the formation of sugar. In conclusion, our analysis does not lead to define this period as stagnation but rather as transition, in which the concept of photosynthesis was clear, even though difficult to treat under physiological and chemical views. From the sixties, the researches of Julius von Sachs will open a new road, thanks also to the research carried out in the transition period. Copyright:

  7. Advantages and disadvantages on photosynthesis measurement ...

    African Journals Online (AJOL)

    PROMOTING ACCESS TO AFRICAN RESEARCH ... Through photosynthesis, green plants and cyanobacteria are able to transfer sunlight energy to ... Measurements of this process are useful in order to understand how it might be controlled ...

  8. Enhancement of crop photosynthesis by diffuse light: quantifying the contributing factors.

    Science.gov (United States)

    Li, T; Heuvelink, E; Dueck, T A; Janse, J; Gort, G; Marcelis, L F M

    2014-07-01

    Plants use diffuse light more efficiently than direct light. However, experimental comparisons between diffuse and direct light have been obscured by co-occurring differences in environmental conditions (e.g. light intensity). This study aims to analyse the factors that contribute to an increase in crop photosynthesis in diffuse light and to quantify their relative contribution under different levels of diffuseness at similar light intensities. The hypothesis is that the enhancement of crop photosynthesis in diffuse light results not only from the direct effects of more uniform vertical and horizontal light distribution in the crop canopy, but also from crop physiological and morphological acclimation. Tomato (Solanum lycopersicum) crops were grown in three greenhouse compartments that were covered by glass with different degrees of light diffuseness (0, 45 and 71 % of the direct light being converted into diffuse light) while maintaining similar light transmission. Measurements of horizontal and vertical photosynthetic photon flux density (PPFD) distribution in the crop, leaf photosynthesis light response curves and leaf area index (LAI) were used to quantify each factor's contribution to an increase in crop photosynthesis in diffuse light. In addition, leaf temperature, photoinhibition, and leaf biochemical and anatomical properties were studied. The highest degree of light diffuseness (71 %) increased the calculated crop photosynthesis by 7·2 %. This effect was mainly attributed to a more uniform horizontal (33 % of the total effect) and vertical PPFD distribution (21 %) in the crop. In addition, plants acclimated to the high level of diffuseness by gaining a higher photosynthetic capacity of leaves in the middle of the crop and a higher LAI, which contributed 23 and 13 %, respectively, to the total increase in crop photosynthesis in diffuse light. Moreover, diffuse light resulted in lower leaf temperatures and less photoinhibition at the top of the canopy when

  9. Water relations, thallus structure and photosynthesis in Negev Desert lichens

    Science.gov (United States)

    Palmer, R. J. Jr; Friedmann, E. I.

    1990-01-01

    The role of lichen thallus structure in water relations and photosynthesis was studied in Ramalina maciformis (Del.) Bory and Teloschistes lacunosus (Rupr.) Sav. Water-vapour adsorption and photosynthesis are dependent upon thallus integrity and are significantly lower in crushed thalli. Cultured phycobiont (Trebouxia sp.) cells are capable of photosynthesis over the same relative humidity range (> 80% RH) as are intact lichens. Thus, water-vapour adsorption by the thallus and physiological adaptation of the phycobiont contribute to the ability of these lichens to photosynthesize in an arid environment. Despite differences in their anatomical structure and water-uptake characteristics, their CO2 incorporation is similar. The two lichens use liquid water differently and they occupy different niches.

  10. Realizing InGaN monolithic solar-photoelectrochemical cells for artificial photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Dahal, R.; Pantha, B. N.; Li, J.; Lin, J. Y.; Jiang, H. X., E-mail: hx.jiang@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

    2014-04-07

    InGaN alloys are very promising for solar water splitting because they have direct bandgaps that cover almost the whole solar spectrum. The demonstration of direct solar-to-fuel conversion without external bias with the sunlight being the only energy input would pave the way for realizing photoelectrochemical (PEC) production of hydrogen by using InGaN. A monolithic solar-PEC cell based on InGaN/GaN multiple quantum wells capable to directly generate hydrogen gas under zero bias via solar water splitting is reported. Under the irradiation by a simulated sunlight (1-sun with 100 mW/cm{sup 2}), a 1.5% solar-to-fuel conversion efficiency has been achieved under zero bias, setting a fresh benchmark of employing III-nitrides for artificial photosynthesis. Time dependent hydrogen gas production photocurrent measured over a prolonged period (measured for 7 days) revealed an excellent chemical stability of InGaN in aqueous solution of hydrobromic acid. The results provide insights into the architecture design of using InGaN for artificial photosynthesis to provide usable clean fuel (hydrogen gas) with the sunlight being the only energy input.

  11. Pattern of photosynthesis in saline indica var. of rice Kala Rata

    International Nuclear Information System (INIS)

    Hegde, B.A.; Joshi, G.V.

    1975-01-01

    The present investigation on Kala Rata deals with the pattern of photosynthesis and the salt stress effect on the photosynthetic efficiency in rice. It is evident from the investigation that chlorophyll synthesis is enhanced with the increasing concentration of NaCl in the bathing medium. However, the efficiency of photosynthesis does not increase with increased chlorophyll production. All ions in leaves can stimulate CO 2 incorporation but inhibit at higher concentration. Analysis of short term products of photosynthesis revealed that aspartate is the major product to be heavily labelled which is evident from autoradiogram. PGA has also appreciable label, where as, malate has the least. It appears therefore, that in rice, both, Calvin as well as C 4 type of pathways are operating. 'Aspartate former' type of rice does not seem to be efficient in photosynthesis as it has C 3 pathway also in operation. (author)

  12. Glucose Synthesis in a Protein-Based Artificial Photosynthesis System.

    Science.gov (United States)

    Lu, Hao; Yuan, Wenqiao; Zhou, Jack; Chong, Parkson Lee-Gau

    2015-09-01

    The objective of this study was to understand glucose synthesis of a protein-based artificial photosynthesis system affected by operating conditions, including the concentrations of reactants, reaction temperature, and illumination. Results from non-vesicle-based glyceraldehyde-3-phosphate (GAP) and glucose synthesis showed that the initial concentrations of ribulose-1,5-bisphosphate (RuBP) and adenosine triphosphate (ATP), lighting source, and temperature significantly affected glucose synthesis. Higher initial concentrations of RuBP and ATP significantly enhanced GAP synthesis, which was linearly correlated to glucose synthesis, confirming the proper functions of all catalyzing enzymes in the system. White fluorescent light inhibited artificial photosynthesis and reduced glucose synthesis by 79.2 % compared to in the dark. The reaction temperature of 40 °C was optimum, whereas lower or higher temperature reduced glucose synthesis. Glucose synthesis in the vesicle-based artificial photosynthesis system reconstituted with bacteriorhodopsin, F 0 F 1 ATP synthase, and polydimethylsiloxane-methyloxazoline-polydimethylsiloxane triblock copolymer was successfully demonstrated. This system efficiently utilized light-induced ATP to drive glucose synthesis, and 5.2 μg ml(-1) glucose was synthesized in 0.78-ml reaction buffer in 7 h. Light-dependent reactions were found to be the bottleneck of the studied artificial photosynthesis system.

  13. The influence of temperature on photosynthesis of different tomato genotypes

    NARCIS (Netherlands)

    Gosiewski, W.; Nilwik, H.J.M.; Bierhuizen, J.F.

    1982-01-01

    Net photosynthesis and dark respiration from whole plants of various tomato genotypes were measured in a closed system. At low irradiance (27 W m−2) and low external CO2 concentration (550 mg m−3), net photosynthesis of 10 genotypes was found to vary between 0.122 and 0.209 mg CO2 m−2 s−1.

  14. 2009 Photosynthesis to be held June 28 - July 3, 2009

    Energy Technology Data Exchange (ETDEWEB)

    Doug Bruce

    2009-07-06

    The capture of solar energy by photosynthesis has had a most profound influence on the development and sustenance of life on earth. It is the engine that has driven the proliferation of life and, as the source of both energy and oxygen, has had a major hand in shaping the forms that life has taken. Both ancient and present day photosynthetic carbon fixation is intimately tied to issues of immediate human concern, global energy and global warming. Decreasing our reliance on fossil fuels by tapping photosynthesis in a more direct way is an attractive goal for sustainable energy. Meeting this challenge means understanding photosynthetic energy conversion at a molecular level, a task requiring perspectives ranging through all disciplines of science. Researchers in photosynthesis have a strong history of working across conventional boundaries and engaging in multidisciplinary collaborations. The Gordon conference in photosynthesis has been a key focal point for the dissemination of new results and the establishment of powerful research collaborations. In this spirit the 2009 Gordon conference on biophysical aspects of photosynthesis will bring together top international researchers from diverse and complementary disciplines, all working towards understanding how photosynthesis converts light into the stable chemical energy that powers so much of our world. Focal points for talks and discussions will include: (1) Watersplitting, structure and function of the oxygen evolving complex; (2) Antenna, the diversity, optimization and regulation of energy capture and transfer; (3) Reaction center structure and function, including functional roles for the protein; (4) Electron transport, proton transport and energy coupling; (5) Photoprotection mechanisms, including secondary electron transport pathways; (6) Biofuels, hydrogen production; and (7) Artificial photosynthesis and solar energy conversion strategies. The 2009 conference will have a close eye on practical applications

  15. Increased SBPase activity improves photosynthesis and grain yield in wheat grown in greenhouse conditions.

    Science.gov (United States)

    Driever, Steven M; Simkin, Andrew J; Alotaibi, Saqer; Fisk, Stuart J; Madgwick, Pippa J; Sparks, Caroline A; Jones, Huw D; Lawson, Tracy; Parry, Martin A J; Raines, Christine A

    2017-09-26

    To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf photosynthesis in wheat, the level of the Calvin-Benson cycle enzyme sedoheptulose-1,7-biphosphatase (SBPase) has been increased through transformation and expression of a Brachypodium distachyon SBPase gene construct. Transgenic lines with increased SBPase protein levels and activity were grown under greenhouse conditions and showed enhanced leaf photosynthesis and increased total biomass and dry seed yield. This showed the potential of improving yield potential by increasing leaf photosynthesis in a crop species such as wheat. The results are discussed with regard to future strategies for further improvement of photosynthesis in wheat.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Authors.

  16. Inhibition of seagrass photosynthesis by ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Trocine, R.P.; Rice, J.D.; Wells, G.N.

    1981-01-01

    Effects of ultraviolet-B radiation on the photosynthesis of seagrasses (Halophila engelmanni Aschers, Halodule wrightii Aschers, and Syringodium filiforme (Kuetz) were examined. The intrinsic tolerance of each seagrass to ultraviolet-B, the presence and effectiveness of photorepair mechanisms to ultraviolet-B-induced photosynthetic inhibition, and the role of epiphytic growth as a shield from ultraviolet-B were investigated. Halodule was found to possess the greatest photosynthetic tolerance for ultraviolet-B. Photosynthesis in Syringodium was slightly more sensitive to ultraviolet-B while Halophila showed relatively little photosynthetic tolerance. Evidence for a photorepair mechanism was found only in Halodule. Syringodium appeared to rely primarily on a thick epidermal cell layer to reduce photosynthetic damage. Halophila seemed to have no morphological or photorepair capabilities to deal with ultraviolet-B. This species appeared to rely on epiphytic and detrital shielding and the shade provided by other seagrasses to reduce ultraviolet-B irradiation to tolerable levels. The presence of epiphytes on leaf surfaces was found to reduce the extent of photosynthetic inhibition from ultraviolet-B exposure in all species. Halophila appears to obtain an increased photosynthetic tolerance to ultraviolet-B as an indirect benefit of chloroplast clumping to avoid photo-oxidation by intense levels of photosynthetically active radiation

  17. The effect of elevated CO{sub 2} concentration on photosynthesis of Sphagnum fuscum

    Energy Technology Data Exchange (ETDEWEB)

    Jauhiainen, J; Silvola, J [Joensuu Univ. (Finland). Dept. of Biology

    1997-12-31

    The objectives of the research were to measure photosynthesis of Sphagnum fuscum in long term exposure to four CO{sub 2} levels at semi-natural conditions, to find out if there is an acclimation of net photosynthesis into prevailing CO{sub 2} concentrations and to measure the moisture dependent net photosynthesis at various CO{sub 2} concentrations of samples grown at different CO{sub 2} concentrations

  18. The effect of elevated CO{sub 2} concentration on photosynthesis of Sphagnum fuscum

    Energy Technology Data Exchange (ETDEWEB)

    Jauhiainen, J.; Silvola, J. [Joensuu Univ. (Finland). Dept. of Biology

    1996-12-31

    The objectives of the research were to measure photosynthesis of Sphagnum fuscum in long term exposure to four CO{sub 2} levels at semi-natural conditions, to find out if there is an acclimation of net photosynthesis into prevailing CO{sub 2} concentrations and to measure the moisture dependent net photosynthesis at various CO{sub 2} concentrations of samples grown at different CO{sub 2} concentrations

  19. The Clinical Research Landscape in Rhode Island.

    Science.gov (United States)

    Mao, George; Ramratnam, Bharat

    2017-01-06

    To present an overview of clinical research activity and the state of medical research funding in Rhode Island. We utilized clinicaltrials.gov registry to profile clinical studies between 2011 to 2016. NIH RePORT and other federal databases were used to extract information on levels of federal funding. Previously published hospital financial reports were reviewed for data on hospital-specific total external research funding. During 2011-2016, 1651 clinical studies were registered in clinicaltrials.gov. Nearly a third of all clinical studies were in oncology (21%) and cardiovascular diseases (10%). Alzheimer's dementia, breast cancer, HIV, and hepatitis C accounted for nearly 17% of all clinical trials. Seventy-five percent (75%) of clinical trials in RI were conducted in hospitals affiliated with Lifespan or Care New England. Financial support for clinical trials largely came from industry (60%) with 23% being supported by the National Institutes of Health (NIH). The rest are funded by nonprofit organizations, charitable foundations, educational institutions, and unlisted concerns. [Full article available at http://rimed.org/rimedicaljournal-2017-01.asp].

  20. A quantum protective mechanism in photosynthesis

    NARCIS (Netherlands)

    Marais, A.; Sinayskiy, I.; Petruccione, F.; van Grondelle, R.

    2015-01-01

    Since the emergence of oxygenic photosynthesis, living systems have developed protective mechanisms against reactive oxygen species. During charge separation in photosynthetic reaction centres, triplet states can react with molecular oxygen generating destructive singlet oxygen. The triplet product

  1. Aquatic CAM photosynthesis: a brief history of its discovery

    Science.gov (United States)

    Keeley, Jon E.

    2014-01-01

    Aquatic CAM (Crassulacean Acid Metabolism) photosynthesis was discovered while investigating an unrelated biochemical pathway concerned with anaerobic metabolism. George Bowes was a significant contributor to this project early in its infancy. Not only did he provide me with some valuable perspectives on peer review rejections, but by working with his gas exchange system I was able to take our initial observations of diel fluctuations in malic acid to the next level, showing this aquatic plant exhibited dark CO2 uptake. CAM is universal in all aquatic species of the worldwide Lycophyta genus Isoetes and non-existent in terrestrial Isoetes. Outside of this genus aquatic CAM has a limited occurrence in three other families, including the Crassulaceae. This discovery led to fascinating adventures in the highlands of the Peruvian Andes in search of Stylites, a terrestrial relative of Isoetes. Stylites is a plant that is hermetically sealed from the atmosphere and obtains all of its carbon from terrestrial sources and recycles carbon through CAM. Considering the Mesozoic origin of Isoetes in shallow pools, coupled with the fact that aquatic Isoetes universally possess CAM, suggests the earliest evolution of CAM photosynthesis was most likely not in terrestrial plants.

  2. Leaf photosynthesis and respiration of three bioenergy crops in relation to temperature and leaf nitrogen: how conserved are biochemical model parameters among crop species?

    Science.gov (United States)

    Archontoulis, S. V.; Yin, X.; Vos, J.; Danalatos, N. G.; Struik, P. C.

    2012-01-01

    Given the need for parallel increases in food and energy production from crops in the context of global change, crop simulation models and data sets to feed these models with photosynthesis and respiration parameters are increasingly important. This study provides information on photosynthesis and respiration for three energy crops (sunflower, kenaf, and cynara), reviews relevant information for five other crops (wheat, barley, cotton, tobacco, and grape), and assesses how conserved photosynthesis parameters are among crops. Using large data sets and optimization techniques, the C3 leaf photosynthesis model of Farquhar, von Caemmerer, and Berry (FvCB) and an empirical night respiration model for tested energy crops accounting for effects of temperature and leaf nitrogen were parameterized. Instead of the common approach of using information on net photosynthesis response to CO2 at the stomatal cavity (An–Ci), the model was parameterized by analysing the photosynthesis response to incident light intensity (An–Iinc). Convincing evidence is provided that the maximum Rubisco carboxylation rate or the maximum electron transport rate was very similar whether derived from An–Ci or from An–Iinc data sets. Parameters characterizing Rubisco limitation, electron transport limitation, the degree to which light inhibits leaf respiration, night respiration, and the minimum leaf nitrogen required for photosynthesis were then determined. Model predictions were validated against independent sets. Only a few FvCB parameters were conserved among crop species, thus species-specific FvCB model parameters are needed for crop modelling. Therefore, information from readily available but underexplored An–Iinc data should be re-analysed, thereby expanding the potential of combining classical photosynthetic data and the biochemical model. PMID:22021569

  3. Conference Support, 23rd Western Photosynthesis Conference 2014, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, Rebekka [Arizona State Univ., Tempe, AZ (United States)

    2015-01-12

    The Western Photosynthesis Conference is a regional conference that is held on an annual basis to bring together researchers primarily from the Western United States to share their newest research advances on photosynthetic processes. The 23rd conference was focused on both fundamental and more applied research on the biological conversion of solar energy to various energy storage forms. Several particular areas of solar energy conversion were emphasized in this conference (see below). Some of these topics, such as carbon limitations on photosynthesis, biomimicry and phenotyping, have traditionally not been incorporated extensively in the Western Photosynthesis Conference. We found that these topics have substantially broadened of the scope of this meeting.

  4. Biochemical approaches to C4 photosynthesis evolution studies: the case of malic enzymes decarboxylases.

    Science.gov (United States)

    Saigo, Mariana; Tronconi, Marcos A; Gerrard Wheeler, Mariel C; Alvarez, Clarisa E; Drincovich, María F; Andreo, Carlos S

    2013-11-01

    C4 photosynthesis enables the capture of atmospheric CO2 and its concentration at the site of RuBisCO, thus counteracting the negative effects of low atmospheric levels of CO2 and high atmospheric levels of O2 (21 %) on photosynthesis. The evolution of this complex syndrome was a multistep process. It did not occur by simply recruiting pre-exiting components of the pathway from C3 ancestors which were already optimized for C4 function. Rather it involved modifications in the kinetics and regulatory properties of pre-existing isoforms of non-photosynthetic enzymes in C3 plants. Thus, biochemical studies aimed at elucidating the functional adaptations of these enzymes are central to the development of an integrative view of the C4 mechanism. In the present review, the most important biochemical approaches that we currently use to understand the evolution of the C4 isoforms of malic enzyme are summarized. It is expected that this information will help in the rational design of the best decarboxylation processes to provide CO2 for RuBisCO in engineering C3 species to perform C4 photosynthesis.

  5. Effect of Bradyrhizobium photosynthesis on stem nodulation of Aeschynomene sensitiva

    OpenAIRE

    Giraud, Eric; Hannibal, Laure; Fardoux, Joël; Verméglio, A.; Dreyfus, Bernard

    2000-01-01

    Some leguminous species of the genus #Aeschynomene$ are specifically stem-nodulated by photosynthetic bradyrhizobia. To study the effect of bacterial photosynthesis during symbiosis, we generated a photosynthesis-negative mutant of the #Bradyrhizobium$ sp. strain ORS278 symbiont of #Aeschynomene sensitiva$. The presence of a functional photosynthetic unit in bacterioids and the high expression of the photosynthetic genes observed in stem nodules demonstrate that the bacteria are photosyntheti...

  6. Estimating Photosynthetic Radiation Use Efficiency Using Incident Light and Photosynthesis of Individual Leaves

    OpenAIRE

    ROSATI, A.; DEJONG, T. M.

    2003-01-01

    It has been theorized that photosynthetic radiation use efficiency (PhRUE) over the course of a day is constant for leaves throughout a canopy if leaf nitrogen content and photosynthetic properties are adapted to local light so that canopy photosynthesis over a day is optimized. To test this hypothesis, ‘daily’ photosynthesis of individual leaves of Solanum melongena plants was calculated from instantaneous rates of photosynthesis integrated over the daylight hours. Instantaneous photosynthes...

  7. International conference on "Photosynthesis research for sustainability-2013: in honor of Jalal A. Aliyev", held during June 5-9, 2013, Baku, Azerbaijan.

    Science.gov (United States)

    Allakhverdiev, Suleyman I; Huseynova, Irada M; Govindjee

    2013-12-01

    In this brief report, we provide a pictorial essay on an international conference "Photosynthesis Research for Sustainability-2013 in honor of Jalal A. Aliyev" that was held in Baku, Azerbaijan, during June 5-9, 2013 ( http://photosynthesis2013.cellreg.org/ ). We begin this report with a brief note on Jalal Aliyev, the honored scientist, and on John Walker (1997 Nobel laureate in Chemistry) who was a distinguished guest and lecturer at the Conference. We briefly describe the Conference, and the program. In addition to the excellent scientific program, a special feature of the Conference was the presentation of awards to nine outstanding young investigators; they are recognized in this report. We have also included several photographs to show the pleasant ambience at this conference. (See http://photosynthesis2013.cellreg.org/Photo-Gallery.php ; https://www.dropbox.com/sh/qcr124dajwffwh6/TlcHBvFu4H?m ; and https://www.copy.com/s/UDlxb9fgFXG9/Baku for more photographs taken by the authors as well as by others.) We invite the readers to the next conferences on "Photosynthesis Research for Sustainability-2014: in honor of Vladimir A. Shuvalov" to be held during June 2-7, 2014, in Pushchino, Russia. Detailed information for this will be posted at the Website: http://photosynthesis2014.cellreg.org/ , and for the subsequent conference on "Photosynthesis Research for Sustainability-2015" to be held in May or June 2015, in Baku, Azerbaijan, at http://photosynthesis2015.cellreg.org/ .

  8. Leaf area and net photosynthesis during development of Prunus serotina seedlings

    Science.gov (United States)

    Stephen B. Horsley; Kurt W. Gottschalk

    1993-01-01

    We used the plastochron index to study the relationship between plant age, leaf age and development, and net photosynthesis of black cherry (Prtmus serotina Ehrh.) seedlings. Leaf area and net photosynthesis were measured on all leaves >=75 mm of plants ranging in age from 7 to 20 plastochrons. Effects of plant developmental stage...

  9. Solar fuels via artificial photosynthesis: From homogeneous photocatalysis in solution to a photoelectrochemical cell

    NARCIS (Netherlands)

    Chen, H.-C.

    2016-01-01

    The conversion and storage of solar energy into fuels provides a valuable solution for the future energy demand of our society. Making fuels via artificial photosynthesis, the so-called solar-to-fuel approach, is viewed as one of the most promising ways to produce clean and renewable energy.

  10. Using Evolution as a Guide to Engineer Kranz-Type C4 photosynthesis

    Directory of Open Access Journals (Sweden)

    Thomas L. Slewinski

    2013-07-01

    Full Text Available Kranz-type C4 photosynthesis has independently and rapidly evolved over sixty times to dramatically increase radiation use efficiency in both monocots and eudicots. Indeed, it is one of the most exceptional examples of convergent evolution in the history of life. The repeated and rapid evolution of Kranz-type C4 suggests that it may be a derivative of a conserved developmental pathway that is present in all angiosperms. Here, I argue that the Kranz-type C4 photosynthetic system is an extension of the endodermis/starch sheath, that is normally only found in the roots and stems, into photosynthetic structures such as leaves. Support for this hypothesis was recently provided by a study that showed that the same genetic pathway that gives rise to the endodermis in roots, the SCARECROW/SHORT-ROOT radial pattering system, also regulates the development of Kranz anatomy and C4 physiology in leaves. This new hypothesis for the evolution of Kranz-type C4 photosynthesis has opened new opportunities to explore the underlying genetic networks that regulate the development and physiology of C4 and provides new potential avenues for the engineering of the mechanism into C3 crops.

  11. Enhancement of photosynthesis in Sorghum bicolor by ultraviolet radiation

    International Nuclear Information System (INIS)

    Johnson, G.A.; Day, T.A.

    2002-01-01

    We assessed the influence of ultraviolet radiation (UV) on net photosynthetic CO 2 assimilation rate (Pn) in Sorghum bicolor, with particular attention to examining whether UV can enhance Pn via direct absorption of UV and absorption of UV-induced blue fluorescence by photosynthetic pigments. A polychromatic UV response spectrum of leaves was constructed by measuring Pn under different UV supplements using filters that had sharp transmission cut-offs from 280 to 382 nm, against a background of non-saturating visible light. When the abaxial surface was irradiated, P n averaged 4.6% higher with the UV supplement that cut-off UV at 311 nm, compared to lower and higher UV wavelength supplements. This former supplement differed from higher wavelength supplements by primarily providing more UV between 320 and 350 nm. To assess the possibility of direct absorption of UV by photosynthetic pigments, we measured the absorbance of extracted chlorophylls. Chlorophyll a had absorbance peaks at 340 and 389 nm that were 49 and 72% of that at the sorét peak. Chlorophyll b had absorbance peaks at 315 and 346 nm that were both 35% of that at the sorét peak. Since the epidermis transmits some UV, the strong UV absorbance of chlorophyll implies a potential role for irradiance beyond the bounds of the conventionally defined photosynthetically active radiation waveband (400–700 nm). To assess the role of absorption of UV-induced blue fluorescence, we measured the UV-induced fluorescence excitation and emission spectra of leaves. Abaxial excitation peaked at 328 nm, while emission peaked at 446 nm. In this analysis, we used our abaxial fluorescence excitation spectrum and the UV photosynthetic inhibition spectrum of Caldwell et al. (1986) to weight the UV irradiance with each cut-off filter, thereby estimating the potential contribution of UV-induced blue fluorescence to photosynthesis and the inhibitory effects of UV irradiance on photosynthesis, respectively. With a non

  12. Evolution of the 3-hydroxypropionate bicycle and recent transfer of anoxygenic photosynthesis into the Chloroflexi

    Science.gov (United States)

    Shih, Patrick M.; Ward, Lewis M.; Fischer, Woodward W.

    2017-10-01

    Various lines of evidence from both comparative biology and the geologic record make it clear that the biochemical machinery for anoxygenic photosynthesis was present on early Earth and provided the evolutionary stock from which oxygenic photosynthesis evolved ca. 2.3 billion years ago. However, the taxonomic identity of these early anoxygenic phototrophs is uncertain, including whether or not they remain extant. Several phototrophic bacterial clades are thought to have evolved before oxygenic photosynthesis emerged, including the Chloroflexi, a phylum common across a wide range of modern environments. Although Chloroflexi have traditionally been thought to be an ancient phototrophic lineage, genomics has revealed a much greater metabolic diversity than previously appreciated. Here, using a combination of comparative genomics and molecular clock analyses, we show that phototrophic members of the Chloroflexi phylum are not particularly ancient, having evolved well after the rise of oxygen (ca. 867 million years ago), and thus cannot be progenitors of oxygenic photosynthesis. Similarly, results show that the carbon fixation pathway that defines this clade—the 3-hydroxypropionate bicycle—evolved late in Earth history as a result of a series of horizontal gene transfer events, explaining the lack of geological evidence for this pathway based on the carbon isotope record. These results demonstrate the role of horizontal gene transfer in the recent metabolic innovations expressed within this phylum, including its importance in the development of a novel carbon fixation pathway.

  13. Effects of high CO2 levels on dynamic photosynthesis: carbon gain, mechanisms, and environmental interactions.

    Science.gov (United States)

    Tomimatsu, Hajime; Tang, Yanhong

    2016-05-01

    Understanding the photosynthetic responses of terrestrial plants to environments with high levels of CO2 is essential to address the ecological effects of elevated atmospheric CO2. Most photosynthetic models used for global carbon issues are based on steady-state photosynthesis, whereby photosynthesis is measured under constant environmental conditions; however, terrestrial plant photosynthesis under natural conditions is highly dynamic, and photosynthetic rates change in response to rapid changes in environmental factors. To predict future contributions of photosynthesis to the global carbon cycle, it is necessary to understand the dynamic nature of photosynthesis in relation to high CO2 levels. In this review, we summarize the current body of knowledge on the photosynthetic response to changes in light intensity under experimentally elevated CO2 conditions. We found that short-term exposure to high CO2 enhances photosynthetic rate, reduces photosynthetic induction time, and reduces post-illumination CO2 burst, resulting in increased leaf carbon gain during dynamic photosynthesis. However, long-term exposure to high CO2 during plant growth has varying effects on dynamic photosynthesis. High levels of CO2 increase the carbon gain in photosynthetic induction in some species, but have no significant effects in other species. Some studies have shown that high CO2 levels reduce the biochemical limitation on RuBP regeneration and Rubisco activation during photosynthetic induction, whereas the effects of high levels of CO2 on stomatal conductance differ among species. Few studies have examined the influence of environmental factors on effects of high levels of CO2 on dynamic photosynthesis. We identified several knowledge gaps that should be addressed to aid future predictions of photosynthesis in high-CO2 environments.

  14. Broad-Scale Comparison of Photosynthesis in Terrestrial and Aquatic Plant Communities

    DEFF Research Database (Denmark)

    Sand-Jensen, Kaj; Krause-Jensen, D.

    1997-01-01

    Comparisons of photosynthesis in terrestrial and aquatic habitats have been impaired by differences in methods and time-scales of measurements. We compiled information on gross photosynthesis at high irradiance and photosynthetic efficiency at low irradiance from 109 published terrestrial studies...... communities probably due to more efficient light utilization and gas exchange in the terrestrial habitats. By contrast only small differences were found within different aquatic plant communities or within different terrestrial plant communities....... of forests, grasslands and crops and 319 aquatic studies of phytoplankton, macrophyte and attached microalgal communities to test if specific differences existed between the communities. Maximum gross photosynthesis and photosynthetic efficiency were systematically higher in terrestrial than in aquatic...

  15. Mathematical-statistical model for analysis of Ulva algal net photosynthesis in Venice lagoon

    International Nuclear Information System (INIS)

    Izzo, G.; Rizzo, V.; Bella, A.; Picci, M.; Giordano, P.

    1996-08-01

    The algal net photosynthesis, an important factor for the characterization of water quality in Venice lagoon, has been studied experimentally providing a mathematical model, validated by using statistical methods. This model relates oxygen production with irradiance, according to a well known law in biological literature. Its observed an inverted proportion between algal oxygen production and temperature, thus seasonality

  16. Invitation to the 17th international congress on photosynthesis research in 2016 : photosynthesis in a changing world

    NARCIS (Netherlands)

    van Amerongen, Herbert; Croce, Roberta

    2016-01-01

    The 17th International Congress on Photosynthesis will be held from August 7 to 12, 2016 in Maastricht, The Netherlands. The congress will include an opening reception, 15 plenary lectures, 28 scientific symposia, many poster sessions, displays by scientific companies, excursions, congress dinner,

  17. The Path of Carbon in Photosynthesis XVI. Kinetic Relationships of the Intermediates in Steady State Photosynthesis

    Science.gov (United States)

    Benson, A. A.; Kawaguchi, S.; Hayes, P.; Calvin, M.

    1952-06-05

    A kinetic study of the accumulation of C{sup 14} in the intermediates of steady state photosynthesis in C{sup 14}O{sub 2} provides information regarding the sequence of reactions involved. The work described applied the radio-chromatographic technique for analysis of the labeled early products. The simultaneous carboxylation reaction resulting in malic acid as well as phosphoglycerate is demonstrated in experiments at high light intensity. A comparison of radioactivities in a number of phosphorylated sugars as a function of time reveals concurrent synthesis of fructose and sedoheptulose phosphates followed by that of ribulose phosphates and later by that of glucose phosphates. The possibility that the cleavage of C{sub 4} compounds to C{sub 2} carbon dioxide acceptors may involve C{sub 7} and C{sub 5} sugars and evidence for this mechanism is presented.

  18. PHOTOSYNTHESIS AT THE FOREFRONT OF A SUSTAINABLE LIFE

    Directory of Open Access Journals (Sweden)

    Paul J.D. Janssen

    2014-06-01

    Full Text Available The development of a sustainable bio-based economy has drawn much attention in recent years, and research to find smart solutions to the many inherent challenges has intensified. In nature, perhaps the best example of an authentic sustainable system is oxygenic photosynthesis. The biochemistry of this intricate process is empowered by solar radiation influx and performed by hierarchically organized complexes composed by photoreceptors, inorganic catalysts, and enzymes which define specific niches for optimizing light-to-energy conversion. The success of this process relies on its capability to exploit the almost inexhaustible reservoirs of sunlight, water, and carbon dioxide to transform photonic energy into chemical energy such as stored in adenosine triphosphate. Oxygenic photosynthesis is responsible for most of the oxygen, fossil fuels, and biomass on our planet. So, even after a few billion years of evolution, this process unceasingly supports life on earth, and probably soon also in outer-space, and inspires the development of enabling technologies for a sustainable global economy and ecosystem. The following review covers some of the major milestones reached in photosynthesis research, each reflecting lasting routes of innovation in agriculture, environmental protection, and clean energy production.

  19. Inhibition of photosynthesis and bleaching of zooxanthellae by the coral pathogen Vibrio shiloi.

    Science.gov (United States)

    Ben-Haim, Y; Banim, E; Kushmaro, A; Loya, Y; Rosenberg, E

    1999-06-01

    Vibrio shiloi is the causative agent of bleaching (loss of endosymbiotic zooxanthellae) of the coral Oculina patagonica in the Mediterranean Sea. To obtain information on the mechanism of bleaching, we examined the effect of secreted material (AK1-S) produced by V. shiloi on zooxanthellae isolated from corals. AK1-S caused a rapid inhibition of photosynthesis of the algae, as measured with a Mini-PAM fluorometer. The inhibition of photosynthesis was caused by (i) ammonia produced during the growth of V. shiloi on protein-containing media and (ii) a non-dialysable heat-resistant factor. This latter material did not inhibit photosynthesis of the algae by itself but, when added to different concentrations of NH4Cl, enhanced the inhibition approximately two- to threefold. Ammonia and the enhancer were effective to different degrees on zooxanthellae isolated from four species of coral examined. In addition to the rapid inhibition of photosynthesis, AK1-S caused bleaching (loss of pigmentation) and lysis of zooxanthellae. Bleaching was more rapid than lysis, reaching a peak (25% bleached algae) after 6 h. The factors in AK1-S responsible for bleaching and lysis were different from those responsible for the inhibition of photosynthesis, because they were heat sensitive, non-dialysable and active in the dark. Thus, the coral pathogen V. shiloi produces an array of extracellular materials that can inhibit photosynthesis, bleach and lyse zooxanthellae.

  20. Canopy Photosynthesis: From Basics to Applications

    NARCIS (Netherlands)

    Hikosaka, Kouki; Niinemets, Ülo; Anten, N.P.R.

    2016-01-01

    A plant canopy, a collection of leaves, is an ecosystem-level unit of photosynthesis that assimilates carbon dioxide and exchanges other gases and energy with the atmosphere in a manner highly sensitive to ambient conditions including atmospheric carbon dioxide and water vapor concentrations, light

  1. A Forgotten Application of the Starch Test: C[subscript 4] Photosynthesis

    Science.gov (United States)

    Harley, Suzanne M.

    2013-01-01

    In many labs on photosynthesis, the presence of starch in leaves is used as an indirect indicator of photosynthetic activity. Students do starch tests on leaves from plants that have been kept under a variety of conditions in order to check parameters for photosynthesis. The starch test can also be used to enable students to discover differences…

  2. Phenotypic engineering of photosynthesis related traits in Arabidopsis thaliana using genome interrogation

    NARCIS (Netherlands)

    Tol, Niels van

    2016-01-01

    Photosynthesis is the process that harvests energy from light, and fixes it as chemical energy. It is performed by cyanobacteria, algae, and plants. The overall solar energy to biomass conversion efficiency of plant photosynthesis is widely considered to be very low. Recent models have indicated

  3. Connecting Biochemical Photosynthesis Models with Crop Models to Support Crop Improvement.

    Science.gov (United States)

    Wu, Alex; Song, Youhong; van Oosterom, Erik J; Hammer, Graeme L

    2016-01-01

    The next advance in field crop productivity will likely need to come from improving crop use efficiency of resources (e.g., light, water, and nitrogen), aspects of which are closely linked with overall crop photosynthetic efficiency. Progress in genetic manipulation of photosynthesis is confounded by uncertainties of consequences at crop level because of difficulties connecting across scales. Crop growth and development simulation models that integrate across biological levels of organization and use a gene-to-phenotype modeling approach may present a way forward. There has been a long history of development of crop models capable of simulating dynamics of crop physiological attributes. Many crop models incorporate canopy photosynthesis (source) as a key driver for crop growth, while others derive crop growth from the balance between source- and sink-limitations. Modeling leaf photosynthesis has progressed from empirical modeling via light response curves to a more mechanistic basis, having clearer links to the underlying biochemical processes of photosynthesis. Cross-scale modeling that connects models at the biochemical and crop levels and utilizes developments in upscaling leaf-level models to canopy models has the potential to bridge the gap between photosynthetic manipulation at the biochemical level and its consequences on crop productivity. Here we review approaches to this emerging cross-scale modeling framework and reinforce the need for connections across levels of modeling. Further, we propose strategies for connecting biochemical models of photosynthesis into the cross-scale modeling framework to support crop improvement through photosynthetic manipulation.

  4. Connecting Biochemical Photosynthesis Models with Crop Models to Support Crop Improvement

    Science.gov (United States)

    Wu, Alex; Song, Youhong; van Oosterom, Erik J.; Hammer, Graeme L.

    2016-01-01

    The next advance in field crop productivity will likely need to come from improving crop use efficiency of resources (e.g., light, water, and nitrogen), aspects of which are closely linked with overall crop photosynthetic efficiency. Progress in genetic manipulation of photosynthesis is confounded by uncertainties of consequences at crop level because of difficulties connecting across scales. Crop growth and development simulation models that integrate across biological levels of organization and use a gene-to-phenotype modeling approach may present a way forward. There has been a long history of development of crop models capable of simulating dynamics of crop physiological attributes. Many crop models incorporate canopy photosynthesis (source) as a key driver for crop growth, while others derive crop growth from the balance between source- and sink-limitations. Modeling leaf photosynthesis has progressed from empirical modeling via light response curves to a more mechanistic basis, having clearer links to the underlying biochemical processes of photosynthesis. Cross-scale modeling that connects models at the biochemical and crop levels and utilizes developments in upscaling leaf-level models to canopy models has the potential to bridge the gap between photosynthetic manipulation at the biochemical level and its consequences on crop productivity. Here we review approaches to this emerging cross-scale modeling framework and reinforce the need for connections across levels of modeling. Further, we propose strategies for connecting biochemical models of photosynthesis into the cross-scale modeling framework to support crop improvement through photosynthetic manipulation. PMID:27790232

  5. Cyanobacteria as an Experimental Platform for Modifying Bacterial and Plant Photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Poul Erik [Copenhagen Plant Science Center (CPSC), Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen (Denmark); Leister, Dario, E-mail: leister@lmu.de [Copenhagen Plant Science Center (CPSC), Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen (Denmark); Plant Molecular Biology (Botany), Department of Biology I, Ludwig-Maximilians-University Munich, Munich (Germany)

    2014-04-21

    One of the fascinating characteristics of photosynthesis is its capacity for repair, self-renewal, and energy storage within chemical bonds. Given the evolutionary history of plant photosynthesis and the patchwork nature of many of its components, it is safe to assume that the light reactions of plant photosynthesis can be improved by genetic engineering (Leister, 2012). The evolutionary precursor of chloroplasts was a microorganism whose biochemistry was very similar to that of present-day cyanobacteria. Many cyanobacterial species are easy to manipulate genetically and grow robustly in liquid cultures that can be easily scaled up into photobioreactors. Therefore, cyanobacteria such as Synechocystis sp. PCC 6803 (hereafter “Synechocystis”) have widely been used for decades as model systems to study the principles of photosynthesis (Table 1). Indeed, genetic engineering based on homologous recombination is well-established in Synechocystis. Moreover, new genetic engineering toolkits, including marker-less gene deletion and replacement strategies needing only a single transformation step (Viola et al., 2014) and novel approaches for chromosomal integration and expression of synthetic gene operons (Bentley et al., 2014), allow for large-scale replacement and/or integration of dozens of genes in reasonable time frames. This makes Synechocystis a very attractive basis for the experimental modification of important processes like photosynthesis, and it also suggests innovative ways of improving modules of related eukaryotic pathways, among them the combination of cyanobacterial and eukaryotic elements using the tools of synthetic biology.

  6. Cyanobacteria as an Experimental Platform for Modifying Bacterial and Plant Photosynthesis

    International Nuclear Information System (INIS)

    Jensen, Poul Erik; Leister, Dario

    2014-01-01

    One of the fascinating characteristics of photosynthesis is its capacity for repair, self-renewal, and energy storage within chemical bonds. Given the evolutionary history of plant photosynthesis and the patchwork nature of many of its components, it is safe to assume that the light reactions of plant photosynthesis can be improved by genetic engineering (Leister, 2012). The evolutionary precursor of chloroplasts was a microorganism whose biochemistry was very similar to that of present-day cyanobacteria. Many cyanobacterial species are easy to manipulate genetically and grow robustly in liquid cultures that can be easily scaled up into photobioreactors. Therefore, cyanobacteria such as Synechocystis sp. PCC 6803 (hereafter “Synechocystis”) have widely been used for decades as model systems to study the principles of photosynthesis (Table 1). Indeed, genetic engineering based on homologous recombination is well-established in Synechocystis. Moreover, new genetic engineering toolkits, including marker-less gene deletion and replacement strategies needing only a single transformation step (Viola et al., 2014) and novel approaches for chromosomal integration and expression of synthetic gene operons (Bentley et al., 2014), allow for large-scale replacement and/or integration of dozens of genes in reasonable time frames. This makes Synechocystis a very attractive basis for the experimental modification of important processes like photosynthesis, and it also suggests innovative ways of improving modules of related eukaryotic pathways, among them the combination of cyanobacterial and eukaryotic elements using the tools of synthetic biology.

  7. Chlorophyll Can Be Reduced in Crop Canopies with Little Penalty to Photosynthesis1[OPEN

    Science.gov (United States)

    Drewry, Darren T.; VanLoocke, Andy; Cho, Young B.

    2018-01-01

    The hypothesis that reducing chlorophyll content (Chl) can increase canopy photosynthesis in soybeans was tested using an advanced model of canopy photosynthesis. The relationship among leaf Chl, leaf optical properties, and photosynthetic biochemical capacity was measured in 67 soybean (Glycine max) accessions showing large variation in leaf Chl. These relationships were integrated into a biophysical model of canopy-scale photosynthesis to simulate the intercanopy light environment and carbon assimilation capacity of canopies with wild type, a Chl-deficient mutant (Y11y11), and 67 other mutants spanning the extremes of Chl to quantify the impact of variation in leaf-level Chl on canopy-scale photosynthetic assimilation and identify possible opportunities for improving canopy photosynthesis through Chl reduction. These simulations demonstrate that canopy photosynthesis should not increase with Chl reduction due to increases in leaf reflectance and nonoptimal distribution of canopy nitrogen. However, similar rates of canopy photosynthesis can be maintained with a 9% savings in leaf nitrogen resulting from decreased Chl. Additionally, analysis of these simulations indicate that the inability of Chl reductions to increase photosynthesis arises primarily from the connection between Chl and leaf reflectance and secondarily from the mismatch between the vertical distribution of leaf nitrogen and the light absorption profile. These simulations suggest that future work should explore the possibility of using reduced Chl to improve canopy performance by adapting the distribution of the “saved” nitrogen within the canopy to take greater advantage of the more deeply penetrating light. PMID:29061904

  8. NOAA Digital Oblique Imagery Collection for the Coasts of Main/New Hampshire, Massachusetts/Rhode Island/Connecticut, and Hudson River/Long Island /NY/NJ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Project: NOAA Digital Orthophotography and Ancillary Oblique Imagery Collection for the Coasts of Main/New Hampshire, Massachusetts/Rhode Island/Connecticut, and...

  9. Sea-floor morphology and sedimentary environments in southern Narragansett Bay, Rhode Island

    Science.gov (United States)

    McMullen, Katherine Y.; Poppe, Lawrence J.; Blackwood, Dann S.; Nardi, Matthew J.; Andring, Matthew A.

    2015-09-09

    Multibeam echosounder data collected by the National Oceanic and Atmospheric Administration along with sediment samples and still and video photography of the sea floor collected by the U.S. Geological Survey were used to interpret sea-floor features and sedimentary environments in southern Narragansett Bay, Rhode Island, as part of a long-term effort to map the sea floor along the northeastern coast of the United States. Sea-floor features include rocky areas and scour depressions in high-energy environments characterized by erosion or nondeposition, and sand waves and megaripples in environments characterized by coarse-grained bedload transport. Two shipwrecks are also located in the study area. Much of the sea floor is relatively featureless within the resolution of the multibeam data; sedimentary environments in these areas are characterized by processes associated with sorting and reworking. This report releases bathymetric data from the multibeam echosounder, grain-size analyses of sediment samples, and photographs of the sea floor and interpretations of the sea-floor features and sedimentary environments. It provides base maps that can be used for resource management and studies of topics such as benthic ecology, contaminant inventories, and sediment transport.

  10. Selective pressures on C4 photosynthesis evolution in grasses through the lens of optimality

    OpenAIRE

    Akcay, Erol; Zhou, Haoran; Helliker, Brent

    2016-01-01

    CO2, temperature, water availability and light intensity were potential selective pressures to propel the initial evolution and global expansion of C4 photosynthesis in grasses. To tease apart the primary selective pressures along the evolutionary trajectory, we coupled photosynthesis and hydraulics models and optimized photosynthesis over stomatal resistance and leaf/fine-root allocation. We also examined the importance of nitrogen reallocation from the dark to the light reactions. Our resul...

  11. Moessbauer spectroscopy in studies of photosynthesis

    International Nuclear Information System (INIS)

    Burda, Kvetoslava

    2008-01-01

    Photosynthesis is a process occurring in certain species of bacteria, algae and higher plants. It transforms solar energy into various forms of energy-rich organic molecules. Photosystem II (PSII) is the 'heart' of the photosynthetic apparatus because it delivers electrons and protons for further steps of the light-driven phases of photosynthesis. There are two enigmatic iron binding structures within the core of photosynthetic apparatus, which play an important role in the electron transfer within PSII. Many investigations focus on the determination of their function which is the key to the understanding of the molecular mechanism of the energy and electron transfer within PSII. Among many methods used in this research field, the Moessbauer spectroscopy is a unique one, which gives the possibility to study changes of the valence and spin states of those two iron sites and the dynamical properties of their protein matrix in the presence of various physiological and stress conditions.

  12. Physical stage of photosynthesis charge separation

    Science.gov (United States)

    Yakovlev, A. G.; Shuvalov, V. A.

    2016-06-01

    An analytical review is given concerning the biophysical aspects of light-driven primary charge separation in photosynthesis reaction centers (RCs) which are special pigment-protein complexes residing in a cell membrane. The primary (physical) stage of charge separation occurs in the pico- and femtosecond ranges and consists of transferring an electron along the active A-branch of pigments. The review presents vast factual material on both the general issues of primary photosynthesis and some more specific topics, including (1) the role of the inactive B-branch of pigments, (2) the effect of the protein environment on the charge separation, and (3) the participation of monomeric bacteriochlorophyll BA in primary electron acceptance. It is shown that the electron transfer and stabilization are strongly influenced by crystallographic water and tyrosine M210 molecules from the nearest environment of BA. A linkage between collective nuclear motions and electron transfer upon charge separation is demonstrated. The nature of the high quantum efficiency of primary charge separation reactions is discussed.

  13. A quantum protective mechanism in photosynthesis

    Science.gov (United States)

    Marais, Adriana; Sinayskiy, Ilya; Petruccione, Francesco; van Grondelle, Rienk

    2015-03-01

    Since the emergence of oxygenic photosynthesis, living systems have developed protective mechanisms against reactive oxygen species. During charge separation in photosynthetic reaction centres, triplet states can react with molecular oxygen generating destructive singlet oxygen. The triplet product yield in bacteria is observed to be reduced by weak magnetic fields. Reaction centres from plants' photosystem II share many features with bacterial reaction centres, including a high-spin iron whose function has remained obscure. To explain observations that the magnetic field effect is reduced by the iron, we propose that its fast-relaxing spin plays a protective role in photosynthesis by generating an effective magnetic field. We consider a simple model of the system, derive an analytical expression for the effective magnetic field and analyse the resulting triplet yield reduction. The protective mechanism is robust for realistic parameter ranges, constituting a clear example of a quantum effect playing a macroscopic role vital for life.

  14. Performance Results for Massachusetts and Rhode Island Deep Energy Retrofit Pilot Community

    Energy Technology Data Exchange (ETDEWEB)

    Gates, C. [Building Science Corporation, Somerville, MA (United States); Neuhauser, K. [Building Science Corporation, Somerville, MA (United States)

    2014-03-01

    Between December, 2009 and December, 2012, 42 deep energy retrofit (DER) projects were completed through a pilot program sponsored by National Grid and conducted in Massachusetts and Rhode Island. Thirty-seven of these projects were comprehensive retrofits while five were partial DERs, meaning that high performance retrofit was implemented for a single major enclosure component or a limited number of major enclosure components. Building Science Corporation developed a consistent "package" of measures in terms of the performance targeted for major building components. Based on the community experience, this DER package is expected to result in yearly source energy use near 110 MMBtu/year or approximately 40% below the Northeast regional average.

  15. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2008-01-01

    ). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower...... during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis...... on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B....

  16. Estimating photosynthetic radiation use efficiency using incident light and photosynthesis of individual leaves.

    Science.gov (United States)

    Rosati, A; Dejong, T M

    2003-06-01

    It has been theorized that photosynthetic radiation use efficiency (PhRUE) over the course of a day is constant for leaves throughout a canopy if leaf nitrogen content and photosynthetic properties are adapted to local light so that canopy photosynthesis over a day is optimized. To test this hypothesis, 'daily' photosynthesis of individual leaves of Solanum melongena plants was calculated from instantaneous rates of photosynthesis integrated over the daylight hours. Instantaneous photosynthesis was estimated from the photosynthetic responses to photosynthetically active radiation (PAR) and from the incident PAR measured on individual leaves during clear and overcast days. Plants were grown with either abundant or scarce N fertilization. Both net and gross daily photosynthesis of leaves were linearly related to daily incident PAR exposure of individual leaves, which implies constant PhRUE over a day throughout the canopy. The slope of these relationships (i.e. PhRUE) increased with N fertilization. When the relationship was calculated for hourly instead of daily periods, the regressions were curvilinear, implying that PhRUE changed with time of the day and incident radiation. Thus, linearity (i.e. constant PhRUE) was achieved only when data were integrated over the entire day. Using average PAR in place of instantaneous incident PAR increased the slope of the relationship between daily photosynthesis and incident PAR of individual leaves, and the regression became curvilinear. The slope of the relationship between daily gross photosynthesis and incident PAR of individual leaves increased for an overcast compared with a clear day, but the slope remained constant for net photosynthesis. This suggests that net PhRUE of all leaves (and thus of the whole canopy) may be constant when integrated over a day, not only when the incident PAR changes with depth in the canopy, but also when it varies on the same leaf owing to changes in daily incident PAR above the canopy. The

  17. Native Bee Diversity and Pollen Foraging Specificity in Cultivated Highbush Blueberry (Ericaceae: Vaccinium corymbosum) in Rhode Island.

    Science.gov (United States)

    Scott, Zachary; Ginsberg, Howard S; Alm, Steven R

    2016-12-01

    We identified 41 species of native bees from a total of 1,083 specimens collected at cultivated highbush blueberry plantings throughout Rhode Island in 2014 and 2015. Andrena spp., Bombus spp., and Xylocopa virginica (L.) were collected most often. Bombus griseocollis (DeGeer), B. impatiens Cresson, B. bimaculatus Cresson, B. perplexus Cresson, and Andrena vicina Smith collected the largest mean numbers of blueberry pollen tetrads. The largest mean percent blueberry pollen loads were carried by the miner bees Andrena bradleyi Viereck (91%), A. carolina Viereck (90%), and Colletes validus Cresson (87%). The largest mean total pollen grain loads were carried by B. griseocollis (549,844), B. impatiens (389,558), X. virginica (233,500), and B. bimaculatus (193,132). Xylocopa virginica was the fourth and fifth most commonly collected bee species in 2014 and 2015, respectively. They exhibit nectar robbing and females carried relatively low blueberry pollen loads (mean 33%). Overall, we found 10 species of bees to be the primary pollinators of blueberries in Rhode Island. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Photosynthesis: an interactive didactic model’s use to the learning and teaching process

    Directory of Open Access Journals (Sweden)

    Vanessa Liesenfeld

    2015-06-01

    Full Text Available Photosynthesis is a complex process that involves the implementation of several reactions which, many times, makes this content difficult for students to understand. The objective of this study was to investigate if an interactive didactic model, crafted with simple materials, could facilitate the understanding and learning of students on photosynthesis. Initially students of first year high school class from a public school Western of Paraná were asked to diagram what they knew about photosynthesis and respond to a questionnaire. It was concluded that many of the students’ prior concepts were general or inaccurate, such as the idea of photosynthesis being the process of respiration in plants, and O2 coming from the CO2, not from the photo-oxidation of water. These prior conceptions were important for planning the approach to the subject. The process of photosynthesis was then covered in lecture and dialogued, using the interactive didactic model to highlight the explanations. A new questionnaire was completed by the students, and concluded that the use of the interactive didactic model was efficient, since it helped to consolidate correct concepts and simultaneously, introduced new ones as well it shook the equivocal relations.

  19. Exploring undergraduates' understanding of photosynthesis using diagnostic question clusters.

    Science.gov (United States)

    Parker, Joyce M; Anderson, Charles W; Heidemann, Merle; Merrill, John; Merritt, Brett; Richmond, Gail; Urban-Lurain, Mark

    2012-01-01

    We present a diagnostic question cluster (DQC) that assesses undergraduates' thinking about photosynthesis. This assessment tool is not designed to identify individual misconceptions. Rather, it is focused on students' abilities to apply basic concepts about photosynthesis by reasoning with a coordinated set of practices based on a few scientific principles: conservation of matter, conservation of energy, and the hierarchical nature of biological systems. Data on students' responses to the cluster items and uses of some of the questions in multiple-choice, multiple-true/false, and essay formats are compared. A cross-over study indicates that the multiple-true/false format shows promise as a machine-gradable format that identifies students who have a mixture of accurate and inaccurate ideas. In addition, interviews with students about their choices on three multiple-choice questions reveal the fragility of students' understanding. Collectively, the data show that many undergraduates lack both a basic understanding of the role of photosynthesis in plant metabolism and the ability to reason with scientific principles when learning new content. Implications for instruction are discussed.

  20. APPARENT DIGESTIBILITY OF RHODE ISLAND RED HEN DIETS CONTAINING Leucaena leucocephala AND Moringa oleifera LEAF MEALS

    Directory of Open Access Journals (Sweden)

    Khaled Abouelezz Fouad Mohammed

    2012-05-01

    Full Text Available This study consisted of two trials aimed to evaluate the dietary digestibility by Rhode Island Red (RIR hens' fed on different levels of Leucaena leucocephala (LLM or Moringa oleifera (MOLM. In each experiment, thirty six Rhode Island Red hens at 36 weeks of age were randomly divided into four groups each of nine birds which were allocated in individual cages. The four groups were corresponded to four dietary treatments containing 0 (control, 5, 10 and 15 % of LLM (Exp 1 or MOLM (Exp 2. All groups received smashed diets containing similar metabolizable energy and crude protein (16% CP and 2900 kcal ME/kg diet, as fed basis. The hens were fed the experimental diets for six weeks and during the last four days, feed intake was individually recorded every day and excreta was totally collected twice daily and weighed individually. Considerable amounts of CP were found in LLM (23.61% DM and MOLM (19.76% DM. The dietary treatments had no significant effect on the intake of dry matter (DM, organic matter (OM, gross energy (GE, crude protein (CP or neutral detergent fiber (NDF in both experiments, while the acid detergent fibers (ADF consumption increased linearly (P

  1. How carotenoids protect bacterial photosynthesis.

    OpenAIRE

    Cogdell, R J; Howard, T D; Bittl, R; Schlodder, E; Geisenheimer, I; Lubitz, W

    2000-01-01

    The essential function of carotenoids in photosynthesis is to act as photoprotective agents, preventing chlorophylls and bacteriochlorophylls from sensitizing harmful photodestructive reactions in the presence of oxygen. Based upon recent structural studies on reaction centres and antenna complexes from purple photosynthetic bacteria, the detailed organization of the carotenoids is described. Then with specific reference to bacterial antenna complexes the details of the photoprotective role, ...

  2. Photosynthetic Properties and Potentials for Improvement of Photosynthesis in Pale Green Leaf Rice under High Light Conditions

    Directory of Open Access Journals (Sweden)

    Junfei Gu

    2017-06-01

    Full Text Available Light is the driving force of plant growth, providing the energy required for photosynthesis. However, photosynthesis is also vulnerable to light-induced damage caused by the production of reactive oxygen species (ROS. Plants have therefore evolved various protective mechanisms such as non-photochemical quenching (NPQ to dissipate excessively absorbed solar energy as heat; however, photoinhibition and NPQ represent a significant loss in solar energy and photosynthetic efficiency, which lowers the yield potential in crops. To estimate light capture and light energy conversion in rice, a genotype with pale green leaves (pgl and a normally pigmented control (Z802 were subjected to high (HL and low light (LL. Chlorophyll content, light absorption, chloroplast micrographs, abundance of light-harvesting complex (LHC binding proteins, electron transport rates (ETR, photochemical and non-photochemical quenching, and generation of ROS were subsequently examined. Pgl had a smaller size of light-harvesting chlorophyll antenna and absorbed less photons than Z802. NPQ and the generation of ROS were also low, while photosystem II efficiency and ETR were high, resulting in improved photosynthesis and less photoinhibition in pgl than Z802. Chlorophyll synthesis and solar conversion efficiency were higher in pgl under HL compared to LL treatment, while Z802 showed an opposite trend due to the high level of photoinhibition under HL. In Z802, excessive absorption of solar energy not only increased the generation of ROS and NPQ, but also exacerbated the effects of increases in temperature, causing midday depression in photosynthesis. These results suggest that photosynthesis and yield potential in rice could be enhanced by truncated light-harvesting chlorophyll antenna size.

  3. Photosynthetic Properties and Potentials for Improvement of Photosynthesis in Pale Green Leaf Rice under High Light Conditions

    Science.gov (United States)

    Gu, Junfei; Zhou, Zhenxiang; Li, Zhikang; Chen, Ying; Wang, Zhiqin; Zhang, Hao; Yang, Jianchang

    2017-01-01

    Light is the driving force of plant growth, providing the energy required for photosynthesis. However, photosynthesis is also vulnerable to light-induced damage caused by the production of reactive oxygen species (ROS). Plants have therefore evolved various protective mechanisms such as non-photochemical quenching (NPQ) to dissipate excessively absorbed solar energy as heat; however, photoinhibition and NPQ represent a significant loss in solar energy and photosynthetic efficiency, which lowers the yield potential in crops. To estimate light capture and light energy conversion in rice, a genotype with pale green leaves (pgl) and a normally pigmented control (Z802) were subjected to high (HL) and low light (LL). Chlorophyll content, light absorption, chloroplast micrographs, abundance of light-harvesting complex (LHC) binding proteins, electron transport rates (ETR), photochemical and non-photochemical quenching, and generation of ROS were subsequently examined. Pgl had a smaller size of light-harvesting chlorophyll antenna and absorbed less photons than Z802. NPQ and the generation of ROS were also low, while photosystem II efficiency and ETR were high, resulting in improved photosynthesis and less photoinhibition in pgl than Z802. Chlorophyll synthesis and solar conversion efficiency were higher in pgl under HL compared to LL treatment, while Z802 showed an opposite trend due to the high level of photoinhibition under HL. In Z802, excessive absorption of solar energy not only increased the generation of ROS and NPQ, but also exacerbated the effects of increases in temperature, causing midday depression in photosynthesis. These results suggest that photosynthesis and yield potential in rice could be enhanced by truncated light-harvesting chlorophyll antenna size. PMID:28676818

  4. Carrying photosynthesis genes increases ecological fitness of cyanophage in silico.

    Science.gov (United States)

    Hellweger, Ferdi L

    2009-06-01

    Several viruses infecting marine cyanobacteria carry photosynthesis genes (e.g. psbA, hli) that are expressed, yield proteins (D1, HLIP) and help maintain the cell's photosynthesis apparatus during the latent period. This increases energy and speeds up virus production, allowing for a reduced latent period (a fitness benefit), but it also increases the DNA size, which slows down new virus production and reduces burst size (a fitness cost). How do these genes affect the net ecological fitness of the virus? Here, this question is explored using a combined systems biology and systems ecology ('systems bioecology') approach. A novel agent-based model simulates individual cyanobacteria cells and virus particles, each with their own genes, transcripts, proteins and other properties. The effect of D1 and HLIP proteins is explicitly considered using a mechanistic photosynthesis component. The model is calibrated to the available database for Prochlorococcus ecotype MED4 and podovirus P-SSP7. Laboratory- and field-scale in silico survival, competition and evolution (gene packaging error) experiments with wild type and genetically engineered viruses are performed to develop vertical survival and fitness profiles, and to determine the optimal gene content. The results suggest that photosynthesis genes are nonessential, increase fitness in a manner correlated with irradiance, and that the wild type has an optimal gene content.

  5. The Forests of Southern New England, 2007: A report on the forest resources of Connecticut, Massachusetts, and Rhode Island

    Science.gov (United States)

    Brett J. Butler; Charles J. Barnett; Susan J. Crocker; Grant M. Domke; Dale Gormanson; William N. Hill; Cassandra M. Kurtz; Tonya Lister; Christopher Martin; Patrick D. Miles; Randall Morin; W. Keith Moser; Mark D. Nelson; Barbara O' Connell; Bruce Payton; Charles H. Perry; Ronald J. Piva; Rachel Riemann; Christopher W. Woodall

    2011-01-01

    This report summarizes the results of the fifth forest inventory of the forests of Southern New England, defined as Connecticut, Massachusetts, and Rhode Island, conducted by the U.S. Forest Service, Forest Inventory and analysis program. Information on forest attributes, ownership, land use change, carbon, timber products, forest health, and statistics and quality...

  6. Measurement of Solar Spectra Relating to Photosynthesis and Solar Cells: An Inquiry Lab for Secondary Science

    Science.gov (United States)

    Ruggirello, Rachel M.; Balcerzak, Phyllis; May, Victoria L.; Blankenship, Robert E.

    2012-01-01

    The process of photosynthesis is central to science curriculum at all levels. This article describes an inquiry-based laboratory investigation developed to explore the impact of light quality on photosynthesis and to connect this process to current research on harvesting solar energy, including bioenergy, artificial photosynthesis, and solar…

  7. Overview of the Plio-Pleistocene geology of Rhodes, Greece. Lithology, calcareous nannofossil biostratigraphy, and sampling of the Kallithea Bay section

    DEFF Research Database (Denmark)

    Thomsen, Erik; Rasmussen, Tine Lander; Hastrup, Annette

    2005-01-01

    The Kallithea Bay section on the east coast of Rhodes represents an overall transgressive succession ranging from fluviatile and brackish water gravel at the base to deep-water marl at the top. The brackish water and near-shore deposits are assigned to the Kritika Formation, while the deep-water ...

  8. Ecosystem respiration depends strongly on photosynthesis in a temperate heath

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, Andreas; Beier, Claus

    2007-01-01

    We measured net ecosystem CO2 flux (F-n) and ecosystem respiration (R-E), and estimated gross ecosystem photosynthesis (P-g) by difference, for two years in a temperate heath ecosystem using a chamber method. The exchange rates of carbon were high and of similar magnitude as for productive forest...... ecosystems with a net ecosystem carbon gain during the second year of 293 +/- 11 g C m(-2) year(-1) showing that the carbon sink strength of heather-dominated ecosystems may be considerable when C. vulgaris is in the building phase of its life cycle. The estimated gross ecosystem photosynthesis and ecosystem.......65) was improved when the P-g rate was incorporated into the model (second year; R-2 = 0.79), suggesting that daytime R-E increased with increasing photosynthesis. Furthermore, the temperature sensitivity of R-E decreased from apparent Q(10) values of 3.3 to 3.9 by the classic equation to a more realistic Q(10...

  9. Electromagnetic Radiation Disturbed the Photosynthesis of Microcystis aeruginosa at the Proteomics Level.

    Science.gov (United States)

    Tang, Chao; Yang, Chuanjun; Yu, Hui; Tian, Shen; Huang, Xiaomei; Wang, Weiyi; Cai, Peng

    2018-01-11

    Photosynthesis of Microcystis aeruginosa under Electromagnetic Radiation (1.8 GHz, 40 V/m) was studied by using the proteomics. A total of 30 differentially expressed proteins, including 15 up-regulated and 15 down-regulated proteins, were obtained in this study. The differentially expressed proteins were significantly enriched in the photosynthesis pathway, in which the protein expression levels of photosystems II cytochrome b559 α subunit, cytochrome C550, PsbY, and F-type ATP synthase (a, b) decreased. Our results indicated that electromagnetic radiation altered the photosynthesis-related protein expression levels, and aimed at the function of photosynthetic pigments, photosystems II potential activity, photosynthetic electron transport process, and photosynthetic phosphorylation process of M. aeruginosa. Based on the above evidence, that photoreaction system may be deduced as a target of electromagnetic radiation on the photosynthesis in cyanobacteria; the photoreaction system of cyanobacteria is a hypothetical "shared target effector" that responds to light and electromagnetic radiation; moreover, electromagnetic radiation does not act on the functional proteins themselves but their expression processes.

  10. Fiscal Year 1988 program report: Rhode Island Water Resources Center

    International Nuclear Information System (INIS)

    Poon, C.P.C.

    1989-07-01

    The State of Rhode Island is active in water resources planning, development, and management activities which include legislation, upgrading of wastewater treatment facilities, upgrading and implementing pretreatment programs, protecting watersheds and aquifers throughout the state. Current and anticipated state water problems are contamination and clean up of aquifers to protect the valuable groundwater resources; protection of watersheds by controlling non-point source pollution; development of pretreatment technologies; and deterioring groundwater quality from landfill leachate or drainage from septic tank leaching field. Seven projects were included covering the following subjects: (1) Radon and its nuclei parents in bedrocks; (2) Model for natural flushing of aquifer; (3) Microbial treatment of heavy metals; (4) Vegetative uptake of nitrate; (5) Microbial process in vegetative buffer strips; (6) Leachate characterization in landfills; and (7) Electrochemical treatment of heavy metals and cyanide

  11. O2-insensitive photosynthesis in C3 plants: its occurrence and a possible explanation

    International Nuclear Information System (INIS)

    Sharkey, T.D.

    1985-01-01

    Leaves of C 3 plants which exhibit a normal O 2 inhibition of CO 2 fixation at less than saturating light intensity were found to exhibit O 2 -insensitive photosynthesis at high light. This behavior was observed in Phaseolus vulgaris L., Xanthium strumarium L., and Scrophularia desertorum (Shaw.) Munz. O 2 -insensitive photosynthesis has been reported in nine other C 3 species and usually occurred when the intercellular CO 2 pressure was about double the normal pressure. A lack of O 2 inhibition of photosynthesis was always accompanied by a failure of increased CO 2 pressure to stimulate photosynthesis to the expected degree. O 2 -insensitive photosynthesis also occurred after plants had been water stressed. Under such conditions, however, photosynthesis became O 2 and CO 2 insensitive at physiological CO 2 pressures. Postillumination CO 2 exchange kinetics showed that O 2 and CO 2 insensitivity was not the result of elimination of photorespiration. It is proposed that O 2 and CO 2 insensitivity occurs when the concentration of phosphate in the chloroplast stroma cannot be both high enough to allow photophosphorylation and low enough to allow starch and sucrose synthesis at the rates required by the rest of the photosynthetic component processes. Under these conditions, the energy diverted to photorespiration does not adversely affect the potential for CO 2 assimilation

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

    International Nuclear Information System (INIS)

    Lu Li; Lv Jinyin; Gong Qingzhu; Gao Junfeng

    2006-01-01

    The effects of the space environment on the chlorophyll fluorescence parameters and photosynthesis characteristics of wheat cultivars, Xinong 1043 M1 and Shaan253 M 1 , were studied. The results showed that the decrement of contents of PS II primary photochemical efficiency (F v /F m ), potential activity (F v /F 0 ), photochemical quenching coefficient (qP) and photosynthesis rate (Pn) were less than that of control, increment of non-photochemical quenching coefficient (qN) were more than that of control. The results suggested that photosynthetic apparatus were damaged, photosynthetic electron transport, photosynthetic primary reaction were inhibited, rate of photosynthesis decreased and growth of M 1 plant were retarded, which leading to thousand kernel weights decreased. (authors)

  13. Archive of Geosample Data and Information from the University of Rhode Island (URI) Graduate School of Oceanography (GSO), Marine Geological Samples Laboratory (MGSL)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Geological Samples Laboratory (MGSL) of the Graduate School of Oceanography (GSO), University of Rhode Island is a partner in the Index to Marine and...

  14. Cost Effectiveness of ASHRAE Standard 90.1-2013 for the State of Rhode Island

    Energy Technology Data Exchange (ETDEWEB)

    Hart, Philip R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Athalye, Rahul A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xie, YuLong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhuge, Jing Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Halverson, Mark A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Loper, Susan A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rosenberg, Michael I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Richman, Eric E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-12-01

    Moving to the ASHRAE Standard 90.1-2013 (ASHRAE 2013) edition from Standard 90.1-2010 (ASHRAE 2010) is cost-effective for the State of Rhode Island. The table below shows the state-wide economic impact of upgrading to Standard 90.1-2013 in terms of the annual energy cost savings in dollars per square foot, additional construction cost per square foot required by the upgrade, and life-cycle cost (LCC) per square foot. These results are weighted averages for all building types in all climate zones in the state, based on weightings shown in Table 4. The methodology used for this analysis is consistent with the methodology used in the national cost-effectiveness analysis. Additional results and details on the methodology are presented in the following sections. The report provides analysis of two LCC scenarios: Scenario 1, representing publicly-owned buildings, considers initial costs, energy costs, maintenance costs, and replacement costs—without borrowing or taxes. Scenario 2, representing privately-owned buildings, adds borrowing costs and tax impacts.

  15. On the wind power rejection in the islands of Crete and Rhodes

    International Nuclear Information System (INIS)

    Katsaprakakis, Dimitris Al.; Papadakis, Nikos; Christakis, Dimitris G.; Zervos, Arthouros

    2007-01-01

    Crete and Rhodes represent the two biggest isolated power systems in Greece. The energy production in both islands is based on thermal power plants. The annual wind energy rejection percentage is calculated for Crete and Rhodes in this paper. The rejected wind energy is defined as the electric energy produced by the wind turbines and not absorbed by the utility network, mainly due to power production system's stability and dynamic security reasons. A parametric calculation of the annual wind energy rejection percentage, in terms of the installed wind power, the power demand and the maximum allowed wind power instant penetration percentage, is accomplished. The methodology takes into account (i) the wind power penetration probability, restricted by the thermal generators technical minima and the maximum allowed wind power instant penetration percentage over the instant power demand; and (ii) the wind power production probability, derived by the islands' wind potential. The present paper indicates that isolated power systems which are based on thermal power plants have a limited wind power installation capacity - in order to achieve and maintain an adequate level of system stability. For a maximum wind power instant penetration percentage of 30% of the power demand, in order to ensure an annual wind energy rejection percentage less than 10%, the total installed wind power should not exceed the 40% of the mean annual power demand. The results of this paper are applicable to medium and great size isolated power systems, with particular features: (i) the power production is based on thermal power plants; (ii) the power demand exhibits intensive seasonal variations and is uncorrelated to the wind data; (iii) the mean annual power demand is greater than 10MW; and (iv) a high wind potential, presenting mean annual wind velocity values greater than 7.5ms-1, is recorded. (Author)

  16. The importance of micrometeorological variations for photosynthesis and transpiration in a boreal coniferous forest

    DEFF Research Database (Denmark)

    Schurgers, Guy; Lagergren, F.; Molder, M.

    2015-01-01

    the importance of vertical variations in light, temperature, CO2 concentration and humidity within the canopy for fluxes of photosynthesis and transpiration of a boreal coniferous forest in central Sweden. A leaf-level photosynthesis-stomatal conductance model was used for aggregating these processes to canopy...... abovecanopy and within-canopy humidity, and despite large gradients in CO2 concentration during early morning hours after nights with stable conditions, neither humidity nor CO2 played an important role for vertical heterogeneity of photosynthesis and transpiration....

  17. Modeling photosynthesis of Spartina alterniflora (smooth cordgrass) impacted by the Deepwater Horizon oil spill using Bayesian inference

    International Nuclear Information System (INIS)

    Wu Wei; Biber, Patrick D; Peterson, Mark S; Gong Chongfeng

    2012-01-01

    To study the impact of the Deepwater Horizon oil spill on photosynthesis of coastal salt marsh plants in Mississippi, we developed a hierarchical Bayesian (HB) model based on field measurements collected from July 2010 to November 2011. We sampled three locations in Davis Bayou, Mississippi (30.375°N, 88.790°W) representative of a range of oil spill impacts. Measured photosynthesis was negative (respiration only) at the heavily oiled location in July 2010 only, and rates started to increase by August 2010. Photosynthesis at the medium oiling location was lower than at the control location in July 2010 and it continued to decrease in September 2010. During winter 2010–2011, the contrast between the control and the two impacted locations was not as obvious as in the growing season of 2010. Photosynthesis increased through spring 2011 at the three locations and decreased starting with October at the control location and a month earlier (September) at the impacted locations. Using the field data, we developed an HB model. The model simulations agreed well with the measured photosynthesis, capturing most of the variability of the measured data. On the basis of the posteriors of the parameters, we found that air temperature and photosynthetic active radiation positively influenced photosynthesis whereas the leaf stress level negatively affected photosynthesis. The photosynthesis rates at the heavily impacted location had recovered to the status of the control location about 140 days after the initial impact, while the impact at the medium impact location was never severe enough to make photosynthesis significantly lower than that at the control location over the study period. The uncertainty in modeling photosynthesis rates mainly came from the individual and micro-site scales, and to a lesser extent from the leaf scale. (letter)

  18. Surviving metabolic arrest: photosynthesis during desiccation and rehydration in resurrection plants.

    Science.gov (United States)

    Challabathula, Dinakar; Puthur, Jos T; Bartels, Dorothea

    2016-02-01

    Photosynthesis is the key process that is affected by dehydration in plants. Desiccation-tolerant resurrection plants can survive conditions of very low relative water content. During desiccation, photosynthesis is not operational, but is recovered within a short period after rehydration. While homoiochlorophyllous resurrection plants retain their photosynthetic apparatus during desiccation, poikilochlorophyllous resurrection species dismantle chloroplasts and degrade chlorophyll but resynthesize them again during rehydration. Dismantling the chloroplasts avoids the photooxidative stress in poikilochlorophyllous resurrection plants, whereas it is minimized in homoiochlorophyllous plants through the synthesis of antioxidant enzymes and protective proteins or metabolites. Although the cellular protection mechanisms in both of these species vary, these mechanisms protect cells from desiccation-induced damage and restore photosynthesis upon rehydration. Several of the proteins synthesized during dehydration are localized in chloroplasts and are believed to play major roles in the protection of photosynthetic structures and in recovery in resurrection species. This review focuses on the strategies of resurrection plants in terms of how they protect their photosynthetic apparatus from oxidative stress during desiccation without membrane damage and with full recovery during rehydration. We review the role of the dehydration-induced protection mechanisms in chloroplasts and how photosynthesis is restored during rehydration. © 2015 New York Academy of Sciences.

  19. Rising CO2 widens the transpiration-photosynthesis optimality space

    Science.gov (United States)

    de Boer, Hugo J.; Eppinga, Maarten B.; Dekker, Stefan C.

    2016-04-01

    Stomatal conductance (gs) and photosynthetic biochemistry, typically expressed by the temperature-adjusted maximum rates of carboxylation (V cmax) and electron transport (Jmax), are key traits in land ecosystem models. Contrary to the many approaches available for simulating gs responses, the biochemical parameters V cmax and Jmax are often treated as static traits in ecosystem models. However, observational evidence indicates that V cmax and Jmax respond to persistent changes in atmospheric CO2. Hence, ecosystem models may be improved by incorporating coordinated responses of photosynthetic biochemistry and gs to atmospheric CO2. Recently, Prentice et al. (2014) proposed an optimality framework (referred to as the Prentice framework from here on) to predict relationships between V cmax and gs based on Fick's law, Rubisco-limited photosynthesis and the carbon costs of transpiration and photosynthesis. Here we show that this framework is, in principle, suited to predict CO2-induced changes in the V cmax -gs relationships. The framework predicts an increase in the V cmax:gs-ratio with higher atmospheric CO2, whereby the slope of this relationship is determined by the carbon costs of transpiration and photosynthesis. For our empirical analyses we consider that the carbon cost of transpiration is positively related to the plant's Huber value (sapwood area/leaf area), while the carbon cost of photosynthesis is positively related to the maintenance cost of the photosynthetic proteins. We empirically tested the predicted effect of CO2 on the V cmax:gs-ratio in two genotypes of Solanum dulcamara (bittersweet) that were grown from seeds to maturity under 200, 400 and 800 ppm CO2 in walk-in growth chambers with tight control on light, temperature and humidity. Seeds of the two Solanum genotypes were obtained from two distinct natural populations; one adapted to well-drained sandy soil (the 'dry' genotype) and one adapted to poorly-drained clayey soil (the 'wet' genotype

  20. Carbon dioxide fixation by artificial photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ibusuki, Takashi; Koike, Kazuhide; Ishitani, Osamu [National Inst. for Resources and Environment, AIST, MITI, Tsukuba, Ibaraki (Japan)

    1993-12-31

    Green plants can absorb atmospheric CO{sub 2} and transform it to sugars, carbohydrates through their photosynthetic systems, but they become the source of CO{sub 2} when they are dead. This is the reason why artificial leaves which can be alive forever should be developed to meet with global warming due to the increase of CO{sub 2} concentration. The goal of artificial photosynthesis is not to construct the same system as the photosynthetic one, but to mimic the ability of green plants to utilize solar energy to make high energy chemicals. Needless to say, the artificial photosynthetic system is desired to be as simple as possible and to be as efficient as possible. From the knowledge on photosynthesis and the results of previous investigations, the critical components of artificial photosynthetic system are understood as follows: (1) light harvesting chromophore, (2) a center for electron transfer and charge separation, (3) catalytic sites for converting small molecules like water and CO{sub 2} (mutilelectron reactions) which are schematically described.

  1. Box photosynthesis modeling results for WRF/CMAQ LSM

    Data.gov (United States)

    U.S. Environmental Protection Agency — Box Photosynthesis model simulations for latent heat and ozone at 6 different FLUXNET sites. This dataset is associated with the following publication: Ran, L., J....

  2. Did Respiration or Photosynthesis Come First

    International Nuclear Information System (INIS)

    Broda, E.

    1979-01-01

    The similarity of the mechanisms in photosynthetic and in oxidative phosphorylation suggests a common origin ( convers ion hypothesis). It is proposed that an early form of electron flow with oxidative phosphorylation ("prerespiration"), to terminal electron acceptors available in a reducing biosphere, was supplemented by a photocatalyst capable of a redox reaction. In this way, cyclic photophosphorylation arose. Further stages in evolution were reverse electron flow powered by ATP, to make NADH as a reductant for CO2 , and subsequently noncyclic electron flow. These processes concomitantly provided the oxidants indispensable for full development of oxidative phosphorylation, i.e. for normal respiration: sulphate, O2 and with participation of the nitrificants, nitrite and nitrate. Thus, prerespiration preceded photosynthesis, and this preceded respiration. It is also suggested that nonredox photoprocesses of the Halobacterium type are not part of the mainstream of bioenergetic evolution. They do not lead to photoprocesses with electron flow. (author)

  3. Evolution of the Z-scheme of photosynthesis: a perspective.

    Science.gov (United States)

    Govindjee; Shevela, Dmitriy; Björn, Lars Olof

    2017-09-01

    The concept of the Z-scheme of oxygenic photosynthesis is in all the textbooks. However, its evolution is not. We focus here mainly on some of the history of its biophysical aspects. We have arbitrarily divided here the 1941-2016 period into three sub-periods: (a) Origin of the concept of two light reactions: first hinted at, in 1941, by James Franck and Karl Herzfeld; described and explained, in 1945, by Eugene Rabinowitch; and a clear hypothesis, given in 1956 by Rabinowitch, of the then available cytochrome experiments: one light oxidizing it and another reducing it; (b) Experimental discovery of the two light reactions and two pigment systems and the Z-scheme of photosynthesis: Robert Emerson's discovery, in 1957, of enhancement in photosynthesis when two light beams (one in the far-red region, and the other of shorter wavelengths) are given together than when given separately; and the 1960 scheme of Robin Hill & Fay Bendall; and (c) Evolution of the many versions of the Z-Scheme: Louis Duysens and Jan Amesz's 1961 experiments on oxidation and reduction of cytochrome f by two different wavelengths of light, followed by the work of many others for more than 50 years.

  4. Operation of trans-thylakoid thiol-metabolizing pathways in photosynthesis

    Directory of Open Access Journals (Sweden)

    Mohamed eKaramoko

    2013-11-01

    Full Text Available Thiol oxidation to disulfides and the reverse reaction, i.e. disulfide reduction to free thiols, are under the control of catalysts in vivo. Enzymatically assisted thiol-disulfide chemistry is required for the biogenesis of all energy-transducing membrane systems. However, until recently, this had only been demonstrated for the bacterial plasma membrane. Long considered to be vacant, the thylakoid lumen has now moved to the forefront of photosynthesis research with the realization that its proteome is far more complicated than initially anticipated. Several lumenal proteins are known to be disulfide bonded in Arabidopsis, highlighting the importance of sulfhydryl oxidation in the thylakoid lumen. While disulfide reduction in the plastid stroma is known to activate several enzymatic activities, it appears that it is the reverse reaction, i.e. thiol oxidation that is required for the activity of several lumen-resident proteins. This paradigm for redox regulation in the thylakoid lumen has opened a new frontier for research in the field of photosynthesis. Of particular significance in this context is the discovery of trans-thylakoid redox pathways controlling disulfide bond formation and reduction, which are required for photosynthesis.

  5. Effects of SO/sub 2/ on photosynthesis and nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)

    Haellgren, J E; Huss, K

    1975-06-15

    Responses of photosynthesis and nitrogen fixation to NaHSO/sub 3/ (10/sup -5/ to 5 x 10/sup -3/ M) were investigated in the lichen Stereocaulon paschale (L.) Fr. and the blue-green alga Anabaena cylindrica Lemmermann. The treatments were performed in buffered media with varying pH (5.8 to 8.1) and light conditions (0 to 32 W x m/sup -2/). The activities of the intact organisms were investigated, under the same environmental conditions, with /sup 14/C liquid scintillation and acetylene reduction techniques respectively. The nitrogen fixation proved to be more susceptible than photosynthesis, in both organisms, and in all cases treatments at pH 5.8 were more inhibitory than at higher pH-values. Treatment with 5 x 10/sup -4/ M NaHSO/sub 3/ at pH 5.8 caused no reduction of photosynthesis in S. paschale, while the inhibition of nitrogen fixation was 97%. For A. cylindrica the corresponding values were 40% and 75% respectively. Short-time treatments of A. cylindrica showed that the nitrogen fixation was more rapidly affected than photosynthesis. The inhibition of nitrogenase activity and CO/sub 2/-fixation was smaller in the dark and increased at higher light intensities. Both processes showed a good capacity for recovery after removal of the NaHSO/sub 3/ solution. Also the clumping ability of A. cylindrica was disturbed by NaHSO/sub 3/ treatments.

  6. Photochemistry and enzymology of photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Radmer, R.

    1979-07-30

    In the first task, a specially designed mass spectrometer system monitors the gas exchange occurring in response to single short flashes of light. This apparatus will be primarily used to study photosystem II donor reactions, such as the photooxidation of hydroxylamine, hydrazine, and hydrogen peroxide. This technique will also be used to study the light-induced exchange of O/sub 2/ and CO/sub 2/ in algae. The second task, biochemical studies, will focus on the role of chloroplast copper in photosynthesis. We propose to isolate, purify, and characterize the chloroplast copper enzyme polyphenol oxidase, and attempt to elucidate its role in photosynthesis. These studies will be integrated with a new program devoted to the biochemical response of the photosynthetic membrane to stress. The third task is a series of studies on the light-harvesting and electron-transport mechanisms of C/sub 4/ plants. This program will address three basic problems: (1) the effect of different preparative procedures on various photosynthetic reactions, with particular emphasis on photosystem II reactions in corn bundle sheath chloroplasts; (2) the development and testing of photosystem II assays; and (3) studies of the stoichiometry of electron carriers in bundle sheath chloroplasts, and whether cyclic phosphorylation could be a major pathway in this tissue.

  7. The Path of Carbon in Photosynthesis VII. Respiration and Photosynthesis

    Science.gov (United States)

    Benson, A. A.; Calvin, M.

    1949-07-21

    The relationship of respiration to photosynthesis in barley seedling leaves and the algae, Chlorella and Scenedesmus, has been investigated using radioactive carbon dioxide and the techniques of paper chromatography and radioautography. The plants are allowed to photosynthesize normally for thirty seconds in c{sup 14}O{sub 2} after which they are allowed to respire in air or helium in the light or dark. Respiration of photosynthetic intermediates as evidenced by the appearance of labeled glutomic, isocitric, fumaric and succinic acids is slower in the light than in the dark. Labeled glycolic acid is observed in barley and algae. It disappears rapidly in the dark and is maintained and increased in quantity in the light in C0{sub 2}-free air.

  8. Insights into heliobacterial photosynthesis and physiology from the genome of Heliobacterium modesticaldum.

    Science.gov (United States)

    Sattley, W Matthew; Blankenship, Robert E

    2010-06-01

    The complete annotated genome sequence of Heliobacterium modesticaldum strain Ice1 provides our first glimpse into the genetic potential of the Heliobacteriaceae, a unique family of anoxygenic phototrophic bacteria. H. modesticaldum str. Ice1 is the first completely sequenced phototrophic representative of the Firmicutes, and heliobacteria are the only phototrophic members of this large bacterial phylum. The H. modesticaldum genome consists of a single 3.1-Mb circular chromosome with no plasmids. Of special interest are genomic features that lend insight to the physiology and ecology of heliobacteria, including the genetic inventory of the photosynthesis gene cluster. Genes involved in transport, photosynthesis, and central intermediary metabolism are described and catalogued. The obligately heterotrophic metabolism of heliobacteria is a key feature of the physiology and evolution of these phototrophs. The conspicuous absence of recognizable genes encoding the enzyme ATP-citrate lyase prevents autotrophic growth via the reverse citric acid cycle in heliobacteria, thus being a distinguishing differential characteristic between heliobacteria and green sulfur bacteria. The identities of electron carriers that enable energy conservation by cyclic light-driven electron transfer remain in question.

  9. THE GENESIS OF PHOTOSYNTHESIS TYPES AS THE BASIS OF ECOLOGICAL EXPANSION OF HALOPHYTIC PLANTS

    Directory of Open Access Journals (Sweden)

    Pyurko O.Ye.

    2011-12-01

    Full Text Available The C3, C4, and CAM photosynthesis types are considerably differed by CO2 absorption intensity, its biochemistry, saturation level, water productivity, biological productivity, and other different features, which secure the plants survival at stress and extreme conditions. The aim of current research was to discover the photosynthesis peculiarities at halophytic plants species (Salicornia europaea L., Halimione pedunculata, Artemisia santonica L., Plantago lanceolata L. by salinity at model and natural conditions, and to generalize data in historical aspect. It was constituted that S. europaea L. was characterized by C3 photosynthesis passage which was switched on CAM CO2 fixation under soil salinity conditions till 4-4,5 %, but glycophyte A.santonica was immanent C4assimilation way of aspartate type.Analysis of literature data and own research allows to find out that in majority the C3photosynthesis dependence from environmental factors described by determinate curve with matched mathematical expression. It was suggested to generalize the data by Lagrange polynomial. The obtained results proved that the pattern of photosynthesis evolution is: C3 → C4 → CAM with commute possibilities: C3 → CAM; C4 → CAM.

  10. Dorsoventral variations in dark chilling effects on photosynthesis and stomatal function in Paspalum dilatatum leaves.

    Science.gov (United States)

    Soares-Cordeiro, Ana Sofia; Driscoll, Simon P; Arrabaça, Maria Celeste; Foyer, Christine H

    2011-01-01

    The effects of dark chilling on the leaf-side-specific regulation of photosynthesis were characterized in the C(4) grass Paspalum dilatatum. CO(2)- and light-response curves for photosynthesis and associated parameters were measured on whole leaves and on each leaf side independently under adaxial and abaxial illumination before and after plants were exposed to dark chilling for one or two consecutive nights. The stomata closed on the adaxial sides of the leaves under abaxial illumination and no CO(2) uptake could be detected on this surface. However, high rates of whole leaf photosynthesis were still observed because CO(2) assimilation rates were increased on the abaxial sides of the leaves under abaxial illumination. Under adaxial illumination both leaf surfaces contributed to the inhibition of whole leaf photosynthesis observed after one night of chilling. After two nights of chilling photosynthesis remained inhibited on the abaxial side of the leaf but the adaxial side had recovered, an effect related to increased maximal ribulose-1,5-bisphosphate carboxylation rates (V(cmax)) and enhanced maximal electron transport rates (J(max)). Under abaxial illumination, whole leaf photosynthesis was decreased only after the second night of chilling. The chilling-dependent inhibition of photosynthesis was located largely on the abaxial side of the leaf and was related to decreased V(cmax) and J(max), but not to the maximal phosphoenolpyruvate carboxylase carboxylation rate (V(pmax)). Each side of the leaf therefore exhibits a unique sensitivity to stress and recovery. Side-specific responses to stress are related to differences in the control of enzyme and photosynthetic electron transport activities.

  11. The paleobiological record of photosynthesis

    OpenAIRE

    William Schopf, J.

    2010-01-01

    Fossil evidence of photosynthesis, documented in Precambrian sediments by microbially laminated stromatolites, cyanobacterial microscopic fossils, and carbon isotopic data consistent with the presence of Rubisco-mediated CO2-fixation, extends from the present to ~3,500 million years ago. Such data, however, do not resolve time of origin of O2-producing photoautotrophy from its anoxygenic, bacterial, evolutionary precursor. Though it is well established that Earth’s ecosystem has been based on...

  12. Algal photosynthesis as the primary driver for a sustainable development in energy, feed, and food production.

    Science.gov (United States)

    Anemaet, Ida G; Bekker, Martijn; Hellingwerf, Klaas J

    2010-11-01

    High oil prices and global warming that accompany the use of fossil fuels are an incentive to find alternative forms of energy supply. Photosynthetic biofuel production represents one of these since for this, one uses renewable resources. Sunlight is used for the conversion of water and CO₂ into biomass. Two strategies are used in parallel: plant-based production via sugar fermentation into ethanol and biodiesel production through transesterification. Both, however, exacerbate other problems, including regional nutrient balancing and the world's food supply, and suffer from the modest efficiency of photosynthesis. Maximizing the efficiency of natural and engineered photosynthesis is therefore of utmost importance. Algal photosynthesis is the system of choice for this particularly for energy applications. Complete conversion of CO₂ into biomass is not necessary for this. Innovative methods of synthetic biology allow one to combine photosynthetic and fermentative metabolism via the so-called Photanol approach to form biofuel directly from Calvin cycle intermediates through use of the naturally transformable cyanobacterium Synechocystis sp. PCC 6803. Beyond providing transport energy and chemical feedstocks, photosynthesis will continue to be used for food and feed applications. Also for this application, arguments of efficiency will become more and more important as the size of the world population continues to increase. Photosynthetic cells can be used for food applications in various innovative forms, e.g., as a substitute for the fish proteins in the diet supplied to carnivorous fish or perhaps--after acid hydrolysis--as a complex, animal-free serum for growth of mammalian cells in vitro.

  13. Algal Photosynthesis as the Primary Driver for a Sustainable Development in Energy, Feed, and Food Production

    Energy Technology Data Exchange (ETDEWEB)

    Anemaet, I.G.; Bekker, G.; Hellingwerf, K.J. [Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV, Amsterdam (Netherlands)

    2010-11-15

    High oil prices and global warming that accompany the use of fossil fuels are an incentive to find alternative forms of energy supply. Photosynthetic biofuel production represents one of these since for this, one uses renewable resources. Sunlight is used for the conversion of water and CO2 into biomass. Two strategies are used in parallel: plant-based production via sugar fermentation into ethanol and biodiesel production through transesterification. Both, however, exacerbate other problems, including regional nutrient balancing and the world's food supply, and suffer from the modest efficiency of photosynthesis. Maximizing the efficiency of natural and engineered photosynthesis is therefore of utmost importance. Algal photosynthesis is the system of choice for this particularly for energy applications. Complete conversion of CO2 into biomass is not necessary for this. Innovative methods of synthetic biology allow one to combine photosynthetic and fermentative metabolism via the so-called Photanol approach to form biofuel directly from Calvin cycle intermediates through use of the naturally transformable cyanobacterium Synechocystis sp. PCC 6803. Beyond providing transport energy and chemical feedstocks, photosynthesis will continue to be used for food and feed applications. Also for this application, arguments of efficiency will become more and more important as the size of the world population continues to increase. Photosynthetic cells can be used for food applications in various innovative forms, e.g., as a substitute for the fish proteins in the diet supplied to carnivorous fish or perhaps-after acid hydrolysis-as a complex, animal-free serum for growth of mammalian cells in vitro.

  14. Algal Photosynthesis as the Primary Driver for a Sustainable Development in Energy, Feed, and Food Production

    Energy Technology Data Exchange (ETDEWEB)

    Anemaet, I G; Bekker, G; Hellingwerf, K J [Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV, Amsterdam (Netherlands)

    2010-11-15

    High oil prices and global warming that accompany the use of fossil fuels are an incentive to find alternative forms of energy supply. Photosynthetic biofuel production represents one of these since for this, one uses renewable resources. Sunlight is used for the conversion of water and CO2 into biomass. Two strategies are used in parallel: plant-based production via sugar fermentation into ethanol and biodiesel production through transesterification. Both, however, exacerbate other problems, including regional nutrient balancing and the world's food supply, and suffer from the modest efficiency of photosynthesis. Maximizing the efficiency of natural and engineered photosynthesis is therefore of utmost importance. Algal photosynthesis is the system of choice for this particularly for energy applications. Complete conversion of CO2 into biomass is not necessary for this. Innovative methods of synthetic biology allow one to combine photosynthetic and fermentative metabolism via the so-called Photanol approach to form biofuel directly from Calvin cycle intermediates through use of the naturally transformable cyanobacterium Synechocystis sp. PCC 6803. Beyond providing transport energy and chemical feedstocks, photosynthesis will continue to be used for food and feed applications. Also for this application, arguments of efficiency will become more and more important as the size of the world population continues to increase. Photosynthetic cells can be used for food applications in various innovative forms, e.g., as a substitute for the fish proteins in the diet supplied to carnivorous fish or perhaps-after acid hydrolysis-as a complex, animal-free serum for growth of mammalian cells in vitro.

  15. Big bang photosynthesis and pregalactic nucleosynthesis of light elements

    Science.gov (United States)

    Audouze, J.; Lindley, D.; Silk, J.

    1985-01-01

    Two nonstandard scenarios for pregalactic synthesis of the light elements (H-2, He-3, He-4, and Li-7) are developed. Big bang photosynthesis occurs if energetic photons, produced by the decay of massive neutrinos or gravitinos, partially photodisintegrate He-4 (formed in the standard hot big bang) to produce H-2 and He-3. In this case, primordial nucleosynthesis no longer constrains the baryon density of the universe, or the number of neutrino species. Alternatively, one may dispense partially or completely with the hot big bang and produce the light elements by bombardment of primordial gas, provided that He-4 is synthesized by a later generation of massive stars.

  16. Big bang photosynthesis and pregalactic nucleosynthesis of light elements

    International Nuclear Information System (INIS)

    Audouze, J.; Lindley, D.; Silk, J.; and Laboratoire Rene Bernas, Orsay, France)

    1985-01-01

    Two nonstandard scenarios for pregalactic synthesis of the light elements ( 2 H, 3 He, 4 He, and 7 Li) are developed. Big bang photosynthesis occurs if energetic photons, produced by the decay of massive neutrinos or gravitinos, partially photodisintegrate 4 He (formed in the standard hot big bang) to produce 2 H and 3 He. In this case, primordial nucleosynthesis no longer constrains the baryon density of the universe, or the number of neutrino species. Alternatively, one may dispense partially or completely with the hot big bang and produce the light elements by bombardment of primordial gas, provided that 4 He is synthesized by a later generation of massive stars

  17. Misconception of biology education student of teacher training and education of Sriwijaya University to the concept of photosynthesis and respiration

    Science.gov (United States)

    Susanti, Rahmi

    2018-05-01

    This study aimed to gain an overview of misconceptions on the concept of photosynthesis and respiration. The study involved 58 students from Biology Education of Sriwijaya University. Collecting data used written test of 16 questions, which are 10 questions of multiple choice and 6 of choice with reason. The results showed that:photosynthesis occurs continuously (37.9%), energy used for photosynthesis are light and heat energy (34.5%), plants take CO2to respiration (47%), plants carry on respiration in the absence of light for photosynthesis (22.4%), respiration in plants occurs only in leaf cells (76.4%), and only animals that take O2 of photosynthesis to respiration (68.9%). The conclusion: 1) on the concept of photosynthesis is still prevailing misconceptions about the concept of the place and time of the occurrence of photosynthesis in plants, the role of the sun in photosynthesis, energy is required in the form of photosynthesis, and the role of photosynthesis for the plant. 2) on the concept of respiration is still prevailing misconceptions about the place of the respiration in plants, gas necessary for respiration of plants, and the plants perform respiration time, as well as the cycle of CO2 and O2 that occurs in nature.

  18. An apparatus for field measurement of photosynthesis activity in plants using radioactive carbon dioxide

    International Nuclear Information System (INIS)

    Varshney, O.P.

    1994-01-01

    An apparatus was designed for rapid and accurate determination of photosynthesis rates in the field. It was standardised with respect to exposure time during which maize leaf was exposed to 14 CO 2 labelled air and the photosynthesis rates were measured

  19. Attitudinal Factors and Personal Characteristics Influence Support for Shellfish Aquaculture in Rhode Island (US) Coastal Waters.

    Science.gov (United States)

    Dalton, Tracey M; Jin, Di

    2018-05-01

    This study explores public interests associated with shellfish aquaculture development in coastal waters of Rhode Island (US). Specifically, we examine (1) the levels of public support for (or opposition to) shellfish aquaculture development and (2) factors driving the levels of support, using survey data and ordinal logistic regressions. Results of the analysis identify several key attitudinal factors affecting individual's support for shellfish aquaculture in Rhode Island (RI). The level of support is positively associated with attitudes related to shellfish aquaculture's benefits to the local economy and its role as a nutritional food option, and negatively influenced by attitudes related to aquaculture farms' effects on aesthetic quality and their interference with other uses. Findings highlight that support for (or opposition to) aquaculture in RI is driven more by attitudes associated with social impacts than by those associated with environmental impacts. The level of support is also affected by personal characteristics related to an individual's participation in recreational activities. For instance, bicycle riders tend to be supportive of shellfish aquaculture while respondents who participate in sailing and birding are less supportive. By identifying the broader public's interests in shellfish aquaculture, findings from this study and others like it can be used to address public concerns, incorporate public perceptions and attitudes into permitting decisions, and develop outreach targeted at specific stakeholder groups.

  20. Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought

    Science.gov (United States)

    Li, Xing; Xiao, Jingfeng; He, Binbin

    2018-04-01

    Amazon forests play an important role in the global carbon cycle and Earth’s climate. The vulnerability of Amazon forests to drought remains highly controversial. Here we examine the impacts of the 2015 drought on the photosynthesis of Amazon forests to understand how solar radiation and precipitation jointly control forest photosynthesis during the severe drought. We use a variety of gridded vegetation and climate datasets, including solar-induced chlorophyll fluorescence (SIF), photosynthetic active radiation (PAR), the fraction of absorbed PAR (APAR), leaf area index (LAI), precipitation, soil moisture, cloud cover, and vapor pressure deficit (VPD) in our analysis. Satellite-derived SIF observations provide a direct diagnosis of plant photosynthesis from space. The decomposition of SIF to SIF yield (SIFyield) and APAR (the product of PAR and fPAR) reveals the relative effects of precipitation and solar radiation on photosynthesis. We found that the drought significantly reduced SIFyield, the emitted SIF per photon absorbed. The higher APAR resulting from lower cloud cover and higher LAI partly offset the negative effects of water stress on the photosynthesis of Amazon forests, leading to a smaller reduction in SIF than in SIFyield and precipitation. We further found that SIFyield anomalies were more sensitive to precipitation and VPD anomalies in the southern regions of the Amazon than in the central and northern regions. Our findings shed light on the relative and combined effects of precipitation and solar radiation on photosynthesis, and can improve our understanding of the responses of Amazon forests to drought.

  1. Variation in photosynthesis and stomatal conductance among red maple (Acer rubrum) urban planted cultivars and wildtype trees in the southeastern United States.

    Science.gov (United States)

    Lahr, Eleanor C; Dunn, Robert R; Frank, Steven D

    2018-01-01

    Photosynthesis is a fundamental process that trees perform over fluctuating environmental conditions. This study of red maple (Acer rubrum L.) characterizes photosynthesis, stomatal conductance, and water use efficiency in planted cultivars relative to wildtype trees. Red maple is common in cities, yet there is little understanding of how physiological processes affect the long-term growth, condition, and ecosystem services provided by urban trees. In the first year of our study, we measured leaf-level gas exchange and performed short-term temperature curves on urban planted cultivars and on suburban and rural wildtype trees. In the second year, we compared urban planted cultivars and urban wildtype trees. In the first year, urban planted trees had higher maximum rates of photosynthesis and higher overall rates of photosynthesis and stomatal conductance throughout the summer, relative to suburban or rural wildtype trees. Urban planted trees again had higher maximum rates of photosynthesis in the second year. However, urban wildtype trees had higher water use efficiency as air temperatures increased and similar overall rates of photosynthesis, relative to cultivars, in mid and late summer. Our results show that physiological differences between cultivars and wildtype trees may relate to differences in their genetic background and their responses to local environmental conditions, contingent on the identity of the horticultural variety. Overall, our results suggest that wildtype trees should be considered for some urban locations, and our study is valuable in demonstrating how site type and tree type can inform tree planting strategies and improve long-term urban forest sustainability.

  2. Promoting the Understanding of Photosynthesis among Elementary School Student Teachers through Text Design

    Science.gov (United States)

    Södervik, Ilona; Mikkilä-Erdmann, Mirjamaija; Vilppu, Henna

    2014-01-01

    The purpose of this study was to investigate elementary school pre-service teachers' understanding of photosynthesis and to examine if a refutational text can support understanding of photosynthesis better than a non-refutational text. A total of 91 elementary school pre-service teachers read either a refutational or a non-refutational text…

  3. Pawtuxet River, Warwick, Rhode Island. Local Flood Damage Reduction Study. Detailed Project Report for Water Resources Development.

    Science.gov (United States)

    1982-06-01

    Warwich (Belmont Park) Rhode Island. Cover Title Reads: Flood Damage Reduction IS. KEY WORDS (Ce൘.. asm towvee aide of mogoseem aid 1~110j IV MeMAw...cost of the premium paid by policy holders. The actual premium is less than the actuarial rate by the amount of the subsidy which represents one facet...coverage limits, therefore it was not necessary to calculate additional coverage premiums based on actuarial rates. The annual average subsidized

  4. Mössbauer spectroscopy in studies of photosynthesis

    Science.gov (United States)

    Burda, Květoslava

    2008-02-01

    Photosynthesis is a process occurring in certain species of bacteria, algae and higher plants. It transforms solar energy into various forms of energy-rich organic molecules. Photosystem II (PSII) is the “heart” of the photosynthetic apparatus because it delivers electrons and protons for further steps of the light-driven phases of photosynthesis. There are two enigmatic iron binding structures within the core of photosynthetic apparatus, which play an important role in the electron transfer within PSII. Many investigations focus on the determination of their function which is the key to the understanding of the molecular mechanism of the energy and electron transfer within PSII. Among many methods used in this research field, the Mössbauer spectroscopy is a unique one, which gives the possibility to study changes of the valence and spin states of those two iron sites and the dynamical properties of their protein matrix in the presence of various physiological and stress conditions.

  5. How to Improve the Mastery of Students’ Concept on Photosynthesis Topic?

    Science.gov (United States)

    Ulfa, K.; Anggraeni, S.; Supriatno, B.

    2017-09-01

    The PPDP learning strategy in this research is the acronym of Practicum method, Presentation-discussion method, Demonstration method, and Presentation-discussion method. This study aims to describe the effect of applying PPDP learning strategies to mastery of high school students’ concepts on photosynthesis topic. The research method is a weak experiment, with the research design “The One-Group Pretest-Postetst Design”. The implementation of the study involved 35 students in one of the high schools in the city of Palembang. The research instrument used is in the form of test equipment, assessment rubric and questionnaire. Data were analyzed using Microsoft Excel and SPSS 24 Program. The statistical result showed that PPDP learning strategy had an effect on improving conceptual and Effective on the achievement of the value on the minimum criteria set by the school. This is due to the transformation of knowledge from hands-on to minds-on through the discovery of facts about the concept of photosynthesis. This fact leads to the construction of further understanding through cognitive sharing when the activities of the discussions formed similarity and consolidation of the concept of photosynthesis intact. In addition, demonstration activities also cause students’ logic of thinking to develop through observation of factors that may affect the rate of photosynthesis. This PPDP learning strategy can be utilized by teachers in explaining photosynthetic topic.

  6. Continuous background light significantly increases flashing-light enhancement of photosynthesis and growth of microalgae.

    Science.gov (United States)

    Abu-Ghosh, Said; Fixler, Dror; Dubinsky, Zvy; Iluz, David

    2015-01-01

    Under specific conditions, flashing light enhances the photosynthesis rate in comparison to continuous illumination. Here we show that a combination of flashing light and continuous background light with the same integrated photon dose as continuous or flashing light alone can be used to significantly enhance photosynthesis and increase microalgae growth. To test this hypothesis, the green microalga Dunaliella salina was exposed to three different light regimes: continuous light, flashing light, and concomitant application of both. Algal growth was compared under three different integrated light quantities; low, intermediate, and moderately high. Under the combined light regime, there was a substantial increase in all algal growth parameters, with an enhanced photosynthesis rate, within 3days. Our strategy demonstrates a hitherto undescribed significant increase in photosynthesis and algal growth rates, which is beyond the increase by flashing light alone. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Plant mineral nutrition, gas exchange and photosynthesis in space: A review

    Science.gov (United States)

    Wolff, S. A.; Coelho, L. H.; Zabrodina, M.; Brinckmann, E.; Kittang, A.-I.

    2013-02-01

    Successful growth and development of higher plants in space rely on adequate availability and uptake of water and nutrients, and efficient energy distribution through photosynthesis and gas exchange. In the present review, literature has been reviewed to assemble the relevant knowledge within space plant research for future planetary missions. Focus has been on fractional gravity, space radiation, magnetic fields and ultimately a combined effect of these factors on gas exchange, photosynthesis and transport of water and solutes. Reduced gravity prevents buoyancy driven thermal convection in the physical environment around the plant and alters transport and exchange of gases and liquids between the plant and its surroundings. In space experiments, indications of root zone hypoxia have frequently been reported, but studies on the influences of the space environment on plant nutrition and water transport are limited or inconclusive. Some studies indicate that uptake of potassium is elevated when plants are grown under microgravity conditions. Based on the current knowledge, gas exchange, metabolism and photosynthesis seem to work properly in space when plants are provided with a well stirred atmosphere and grown at moderate light levels. Effects of space radiation on plant metabolism, however, have not been studied so far in orbit. Ground experiments indicated that shielding from the Earth's magnetic field alters plant gas exchange and metabolism, though more studies are required to understand the effects of magnetic fields on plant growth. It has been shown that plants can grow and reproduce in the space environment and adapt to space conditions. However, the influences of the space environment may result in a long term effect over multiple generations or have an impact on the plants' role as food and part of a regenerative life support system. Suggestions for future plant biology research in space are discussed.

  8. The Path of Carbon in Photosynthesis XV. Ribulose and Sedoheptulose

    Science.gov (United States)

    Benson, A. A.; Bassham, J. A.; Calvin, M.; Hall, A. G.; Hirsch, H.; Kawaguchi, S.; Lynch, V.; Tolbert, N. E.

    1952-01-01

    The intermediates of carbon dioxide reduction by plants include phosphorylated derivatives of hydroxy acids and sugars. Their identification became possible when the use of labeled carbon dioxide permitted discrimination between the earliest products and the many other components of photosynthetic tissues. A number of compounds were identified by virtue of the chemical and physical properties of the radioactive compounds in tracer amounts and by direct comparison of these properties with those of suspected known metabolic intermediates. It became apparent that several labeled compounds found in short exposures to radioactive carbon dioxide were not substances previously identified as metabolic intermediates. Two phosphate esters in particular were observed in the products of the first few seconds of steady-state photosynthesis by all the photosynthetic microorganisms and higher plants examined in this laboratory. These esters have been isolated by paper chromatography in tracer quantities and enzymatically hydrolyzed to give two sugars, ribulose and sedoheptulose. This paper contains a description of the chemical identification of these sugars and some observations and suggestions regarding the function of their esters. The general importance of these compounds in photosynthesis was summarized before their identification. The products of photosynthesis with C{sup 14}O{sub 2} by each plant included phosphate esters of the same two then unknown compounds in addition to those of the expected glucose, fructose, dihydroxyacetone and glyceric acid. As the time of steady-state photosynthesis in C{sup 14}O{sub 2} decreased, the fractions of total fixed radiocarbon in the esters of the two unidentified compounds increased.

  9. Photosynthesis of amphibious and obligately submerged plants in CO2-rich lowland streams.

    Science.gov (United States)

    Sand-Jensen, Kaj; Frost-Christensen, Henning

    1998-11-01

    Small unshaded streams in lowland regions receive drainage water with high concentrations of free␣CO 2 , and they support an abundant growth of amphibious and obligately submerged plants. Our first objective was to measure the CO 2 regime during summer in a wide range of small alkaline Danish streams subject to wide variation in temperature, O 2 and CO 2 during the day. The second objective was to determine the effect of these variations on daily changes in light-saturated photosynthesis in water of a homophyllous and a heterophyllous amphibious species that only used CO 2 , and an obligately submerged species capable of using both HCO - 3 and CO 2 . We found that the median CO 2 concentrations of the streams were 11 and 6 times above air saturation in the morning and the afternoon, respectively, but stream sites with dense plant growth had CO 2 concentrations approaching air saturation in the afternoon. In contrast, outlets from lakes had low CO 2 concentrations close to, or below, air saturation. The amphibious species showed a reduction of photosynthesis in water from morning to afternoon along with the decline in CO 2 concentrations, while increasing temperature and O 2 had little effect on photosynthesis. Photosynthesis of the obligately submerged species varied little with the change of CO 2 because of HCO 3 - - use, and variations were mostly due to changes in O 2 concentration. Independent measurements showed that changes in temperature, O 2 and CO 2 could account for the daily variability of photosynthesis of all three species in water. The results imply that CO 2 supersaturation in small lowland streams is important for the rich representation of amphibious species and their contribution to system photosynthesis.

  10. Prokaryotic photosynthesis and phototrophy illuminated

    DEFF Research Database (Denmark)

    Bryant, Donald A; Frigaard, Niels-Ulrik

    2006-01-01

    Genome sequencing projects are revealing new information about the distribution and evolution of photosynthesis and phototrophy. Although coverage of the five phyla containing photosynthetic prokaryotes (Chlorobi, Chloroflexi, Cyanobacteria, Proteobacteria and Firmicutes) is limited and uneven...... components that have not yet been described. Metagenomics has already shown how the relatively simple phototrophy based upon rhodopsins has spread laterally throughout Archaea, Bacteria and eukaryotes. In this review, we present examples that reflect recent advances in phototroph biology as a result...

  11. Inhibition of seagrass photosynthesis by ultraviolet-B radiation.

    Science.gov (United States)

    Trocine, R P; Rice, J D; Wells, G N

    1981-07-01

    Effects of ultraviolet-B radiation on the photosynthesis of seagrasses (Halophila engelmanni Aschers, Halodule wrightii Aschers, and Syringodium filiforme Kütz) were examined. The intrinsic tolerance of each seagrass to ultraviolet-B, the presence and effectiveness of photorepair mechanisms to ultraviolet-B-induced photosynthetic inhibition, and the role of epiphytic growth as a shield from ultraviolet-B were investigated.Halodule was found to possess the greatest photosynthetic tolerance for ultraviolet-B. Photosynthesis in Syringodium was slightly more sensitive to ultraviolet-B while Halophila showed relatively little photosynthetic tolerance. Evidence for a photorepair mechanism was found only in Halodule. This mechanism effectively attenuated photosynthetic inhibition induced by ultraviolet-B dose rates and dosages in excess of natural conditions. Syringodium appeared to rely primarily on a thick epidermal cell layer to reduce photosynthetic damage. Halophila seemed to have no morphological or photorepair capabilities to deal with ultraviolet-B. This species appeared to rely on epiphytic and detrital shielding and the shade provided by other seagrasses to reduce ultraviolet-B irradiation to tolerable levels. The presence of epiphytes on leaf surfaces was found to reduce the extent of photosynthetic inhibition from ultraviolet-B exposure in all species.Observations obtained in this study seem to suggest the possibility of anthocyanin and/or other flavonoid synthesis as an adaptation to long term ultraviolet-B irradiation by these species. In addition, Halophila appears to obtain an increased photosynthetic tolerance to ultraviolet-B as an indirect benefit of chloroplast clumping to avoid photo-oxidation by intense levels of photosynthetically active radiation.

  12. Origin and spread of photosynthesis based upon conserved sequence features in key bacteriochlorophyll biosynthesis proteins.

    Science.gov (United States)

    Gupta, Radhey S

    2012-11-01

    The origin of photosynthesis and how this capability has spread to other bacterial phyla remain important unresolved questions. I describe here a number of conserved signature indels (CSIs) in key proteins involved in bacteriochlorophyll (Bchl) biosynthesis that provide important insights in these regards. The proteins BchL and BchX, which are essential for Bchl biosynthesis, are derived by gene duplication in a common ancestor of all phototrophs. More ancient gene duplication gave rise to the BchX-BchL proteins and the NifH protein of the nitrogenase complex. The sequence alignment of NifH-BchX-BchL proteins contain two CSIs that are uniquely shared by all NifH and BchX homologs, but not by any BchL homologs. These CSIs and phylogenetic analysis of NifH-BchX-BchL protein sequences strongly suggest that the BchX homologs are ancestral to BchL and that the Bchl-based anoxygenic photosynthesis originated prior to the chlorophyll (Chl)-based photosynthesis in cyanobacteria. Another CSI in the BchX-BchL sequence alignment that is uniquely shared by all BchX homologs and the BchL sequences from Heliobacteriaceae, but absent in all other BchL homologs, suggests that the BchL homologs from Heliobacteriaceae are primitive in comparison to all other photosynthetic lineages. Several other identified CSIs in the BchN homologs are commonly shared by all proteobacterial homologs and a clade consisting of the marine unicellular Cyanobacteria (Clade C). These CSIs in conjunction with the results of phylogenetic analyses and pair-wise sequence similarity on the BchL, BchN, and BchB proteins, where the homologs from Clade C Cyanobacteria and Proteobacteria exhibited close relationship, provide strong evidence that these two groups have incurred lateral gene transfers. Additionally, phylogenetic analyses and several CSIs in the BchL-N-B proteins that are uniquely shared by all Chlorobi and Chloroflexi homologs provide evidence that the genes for these proteins have also been

  13. Strategies for Efficient Charge Separation and Transfer in Artificial Photosynthesis of Solar Fuels.

    Science.gov (United States)

    Xu, Yuxing; Li, Ailong; Yao, Tingting; Ma, Changtong; Zhang, Xianwen; Shah, Jafar Hussain; Han, Hongxian

    2017-11-23

    Converting sunlight to solar fuels by artificial photosynthesis is an innovative science and technology for renewable energy. Light harvesting, photogenerated charge separation and transfer (CST), and catalytic reactions are the three primary steps in the processes involved in the conversion of solar energy to chemical energy (SE-CE). Among the processes, CST is the key "energy pump and delivery" step in determining the overall solar-energy conversion efficiency. Efficient CST is always high priority in designing and assembling artificial photosynthesis systems for solar-fuel production. This Review not only introduces the fundamental strategies for CST but also the combinatory application of these strategies to five types of the most-investigated semiconductor-based artificial photosynthesis systems: particulate, Z-scheme, hybrid, photoelectrochemical, and photovoltaics-assisted systems. We show that artificial photosynthesis systems with high SE-CE efficiency can be rationally designed and constructed through combinatory application of these strategies, setting a promising blueprint for the future of solar fuels. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Chloroplast two-component systems: evolution of the link between photosynthesis and gene expression.

    Science.gov (United States)

    Puthiyaveetil, Sujith; Allen, John F

    2009-06-22

    Two-component signal transduction, consisting of sensor kinases and response regulators, is the predominant signalling mechanism in bacteria. This signalling system originated in prokaryotes and has spread throughout the eukaryotic domain of life through endosymbiotic, lateral gene transfer from the bacterial ancestors and early evolutionary precursors of eukaryotic, cytoplasmic, bioenergetic organelles-chloroplasts and mitochondria. Until recently, it was thought that two-component systems inherited from an ancestral cyanobacterial symbiont are no longer present in chloroplasts. Recent research now shows that two-component systems have survived in chloroplasts as products of both chloroplast and nuclear genes. Comparative genomic analysis of photosynthetic eukaryotes shows a lineage-specific distribution of chloroplast two-component systems. The components and the systems they comprise have homologues in extant cyanobacterial lineages, indicating their ancient cyanobacterial origin. Sequence and functional characteristics of chloroplast two-component systems point to their fundamental role in linking photosynthesis with gene expression. We propose that two-component systems provide a coupling between photosynthesis and gene expression that serves to retain genes in chloroplasts, thus providing the basis of cytoplasmic, non-Mendelian inheritance of plastid-associated characters. We discuss the role of this coupling in the chronobiology of cells and in the dialogue between nuclear and cytoplasmic genetic systems.

  15. Gaseous NO2 effects on stomatal behavior, photosynthesis and respiration of hybrid poplar leaves

    Science.gov (United States)

    In this study, we used poplar as a model plant and investigated the effects of gaseous nitrogen dioxide (NO2, 4 microliter per liter) on stomatal conductance, photosynthesis, dark- and photorespiration of Populus alba x Populus berolinensis hybrid leaves using the photosynthesis system and scanning...

  16. 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)

  17. Effects of primitive photosynthesis on Earth's early climate system

    Science.gov (United States)

    Ozaki, Kazumi; Tajika, Eiichi; Hong, Peng K.; Nakagawa, Yusuke; Reinhard, Christopher T.

    2018-01-01

    The evolution of different forms of photosynthetic life has profoundly altered the activity level of the biosphere, radically reshaping the composition of Earth's oceans and atmosphere over time. However, the mechanistic impacts of a primitive photosynthetic biosphere on Earth's early atmospheric chemistry and climate are poorly understood. Here, we use a global redox balance model to explore the biogeochemical and climatological effects of different forms of primitive photosynthesis. We find that a hybrid ecosystem of H2-based and Fe2+-based anoxygenic photoautotrophs—organisms that perform photosynthesis without producing oxygen—gives rise to a strong nonlinear amplification of Earth's methane (CH4) cycle, and would thus have represented a critical component of Earth's early climate system before the advent of oxygenic photosynthesis. Using a Monte Carlo approach, we find that a hybrid photosynthetic biosphere widens the range of geochemical conditions that allow for warm climate states well beyond either of these metabolic processes acting in isolation. Our results imply that the Earth's early climate was governed by a novel and poorly explored set of regulatory feedbacks linking the anoxic biosphere and the coupled H, C and Fe cycles. We suggest that similar processes should be considered when assessing the potential for sustained habitability on Earth-like planets with reducing atmospheres.

  18. Regulation of Calcium on Peanut Photosynthesis Under Low Night Temperature Stress

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-fei; HAN Xiao-ri; ZHAN Xiu-mei; YANG Jin-feng; WANG Yu-zhi; SONG Qiao-bo; CHEN Xin

    2013-01-01

    The effects of different levels of CaCl2 on photosynthesis under low night temperature (8°C) stress in peanuts were studied in order to ifnd out the appropriate concentration of Ca2+ through the artiifcial climate chamber potted culture test. The results indicated that Ca2+, by means of improving the stomatal conductivity of peanut leaves under low night temperature stress, may mitigate the decline of photosynthetic rate in the peanut leaves. The regulation with 15 mmol L-1 CaCl2 (Ca15) was the most effective, compared with other treatments. Subsequently, the improvement of Ca2+ on peanut photosynthesis under low night temperature stress was validated further through spraying withCa15, Ca2+ chelator (ethylene glycol bis(2-aminoethyl) tetraacetic acid; EGTA) and calmodulin antagonists (trilfuonerazine; TFP).And CaM (Ca2+-modulin) played an important role in the nutritional signal transduction for Ca2+ mitigating photosynthesis limitations in peanuts under low night temperature stress.

  19. Crassulacean acid metabolism enhances underwater photosynthesis and diminishes photorespiration in the aquatic plant Isoetes australis

    DEFF Research Database (Denmark)

    Pedersen, Ole; Rich, S.M.; Pulido Pérez, Cristina

    2011-01-01

    Underwater photosynthesis by aquatic plants is often limited by low availability of CO2, and photorespiration can be high. Some aquatic plants utilize crassulacean acid metabolism (CAM) photosynthesis. The benefits of CAM for increased underwater photosynthesis and suppression of photorespiration...... photorespiration was evident at a range of O2 concentrations, including values below air equilibrium. At a high O2 concentration of 2.2-fold the atmospheric equilibrium concentration, net photosynthesis was reduced substantially and, although it remained positive in leaves containing high malate concentrations...... were evaluated for Isoetes australis, a submerged plant that inhabits shallow temporary rock pools. • Leaves high or low in malate were evaluated for underwater net photosynthesis and apparent photorespiration at a range of CO2 and O2 concentrations. • CAM activity was indicated by 9.7-fold higher leaf...

  20. Ecosystem warming does not affect photosynthesis or aboveground autotrophic respiration for boreal black spruce

    Energy Technology Data Exchange (ETDEWEB)

    Bronson, D.R. [Wyoming Univ., Laramie, WY (United States). Dept. of Renewable Resources; Gower, S.T. [Wisconsin Univ., Madison, WI (United States). Dept. of Forest Ecology and Management

    2010-04-15

    Substantial increases in climatic temperatures may cause boreal forests to become a carbon source. An improved understanding of the effect of climatic warming on photosynthesis and autotrophic respiration is needed in order to determine the impact of temperature increases on net carbon balances. This study measured the light-saturated photosynthesis foliage respiration and stem respiration of black spruce in heated and control plots during a 3-year period at a site located in Thompson, Manitoba. Greenhouses and soil-heating cables were used to maintain air and soil temperatures at 5 degrees C above ambient air and soil temperatures. Studies were conducted to determine the influence of soil and air warming; soil-only warming; and greenhouses maintained at ambient temperatures. The study showed that treatment differences for photosynthesis, foliage respiration, and stem respiration were not significant over the 3-year period. Results suggested that black spruce may not have significant changes in photosynthesis or respiration rates in warmer climates. 38 refs., 3 tabs., 4 figs.

  1. Role of seagrass photosynthesis in root aerobic processes.

    Science.gov (United States)

    Smith, R D; Dennison, W C; Alberte, R S

    1984-04-01

    The role of shoot photosynthesis as a means of supporting aerobic respiration in the roots of the seagrass Zostera marina was examined. O(2) was transported rapidly (10-15 minutes) from the shoots to the root-rhizome tissues upon shoot illumination. The highest rates of transport were in shoots possessing the greatest biomass and leaf area. The rates of O(2) transport do not support a simple gas phase diffusion mechanism. O(2) transport to the root-rhizome system supported aerobic root respiration and in many cases exceeded respiratory requirements leading to O(2) release from the subterranean tissue. Release of O(2) can support aerobic processes in reducing sediments typical of Z. marina habitats. Since the root-rhizome respiration is supported primarily under shoot photosynthetic conditions, then the daily period of photosynthesis determines the diurnal period of root aerobiosis.

  2. Anthocyanin-dependent anoxygenic photosynthesis in coloured flower petals?

    Science.gov (United States)

    Lysenko, Vladimir; Varduny, Tatyana

    2013-11-01

    Chlorophylless flower petals are known to be composed of non-photosynthetic tissues. Here, we show that the light energy storage that can be photoacoustically measured in flower petals of Petunia hybrida is approximately 10-12%. We found that the supposed chlorophylless photosynthesis is an anoxygenic, anthocyanin-dependent process occurring in blue flower petals (ADAPFP), accompanied by non-respiratory light-dependent oxygen uptake and a 1.5-fold photoinduced increase in ATP levels. Using a simple, adhesive tape stripping technique, we have obtained a backside image of an intact flower petal epidermis, revealing sword-shaped ingrowths connecting the cell wall and vacuole, which is of interest for the further study of possible vacuole-related photosynthesis. Approaches to the interpretations of ADAPFP are discussed, and we conclude that these results are not impossible in terms of the known photochemistry of anthocyanins.

  3. Ecological Understanding 1: Ways of Experiencing Photosynthesis.

    Science.gov (United States)

    Carlsson, Britta

    2002-01-01

    Investigates 10 student teachers' understanding of the different ways in which the function of the ecosystem could be experienced. Explores the functional aspects of the ecosystem using a system approach. Concludes that the idea of transformation is crucial to more complex ways of understanding photosynthesis. (Contains 62 references.) (Author/YDS)

  4. Salinity-dependent limitation of photosynthesis and oxygen exchange in microbial mats

    DEFF Research Database (Denmark)

    Garcia-Pichel, F.; Kühl, Michael; Nübel, U.

    1999-01-01

    was specific for each community and in accordance with optimal performance at the respective salinity of origin. This pattern was lost after long-term exposure to varying salinities when responses to salinity were found to approach a general pattern of decreasing photosynthesis and oxygen exchange capacity...... with increasing salinity. Exhaustive measurements of oxygen export in the light, oxygen consumption in the dark and gross photosynthesis indicated that a salinity-dependent limitation of all three parameters occurred. Maximal values for all three parameters decreased exponentially with increasing salinity...

  5. Estimating photosynthesis and concurrent export rates in C3 and C4 species at ambient and elevated CO2

    International Nuclear Information System (INIS)

    Grodzinski, B.; Jiao, J.; Leonardos, E.D.

    1998-01-01

    The ability of 21 C3 and C4 monocot and dicot species to rapidly export newly fixed C in the light at both ambient and enriched CO2 levels was compared. Photosynthesis and concurrent export rates were estimated during isotopic equilibrium of the transport sugars using a steady-state 14CO2-labeling procedure. At ambient CO2 photosynthesis and export rates for C3 species were 5 to 15 and 1 to 10 micromole C m-2 s-1, respectively, and 20 to 30 and 15 to 22 micromole C m-2 s-1, respectively, for C4 species. A linear regression plot of export on photosynthesis rate of all species had a correlation coefficient of 0.87. When concurrent export was expressed as a percentage of photosynthesis, several C3 dicots that produced transport sugars other than Suc had high efflux rates relative to photosynthesis, comparable to those of C4 species. At high CO2 photosynthetic and export rates were only slightly altered in C4 species, and photosynthesis increased but export rates did not in all C3 species. The C3 species that had high efflux rates relative to photosynthesis at ambient CO2 exported at rates comparable to those of C4 species on both an absolute basis and as a percentage of photosynthesis. At ambient CO2 there were strong linear relationships between photosynthesis, sugar synthesis, and concurrent export. However, at high CO2 the relationships between photosynthesis and export rate and between sugar synthesis and export rate were not as strong because sugars and starch were accumulated

  6. Stomatal and non-stomatal factors regulated the photosynthesis of soybean seedlings in the present of exogenous bisphenol A.

    Science.gov (United States)

    Jiao, Liya; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2017-11-01

    Bisphenol A (BPA) is an emerging environmental endocrine disruptor that has toxic effects on plants growth. Photosynthesis supplies the substances and energy required for plant growth, and regulated by stomatal and non-stomatal factors. Therefore, in this study, to reveal how BPA affects photosynthesis in soybean seedlings (Glycine max L.) from the perspective of stomatal and non-stomatal factors, the stomatal factors (stomatal conductance and behaviours) and non-stomatal factors (Hill reaction, apparent quantum efficiency, Rubisco activity, carboxylation efficiency, the maximum Rubisco carboxylation velocity, ribulose-1,5-bisphospate regeneration capacities mediated by maximum electron transport rates, and triose phosphate utilization rate) were investigated using a portable photosynthesis system. Moreover, the pollution of BPA in the environment was simulated. The results indicate that low-dose BPA enhanced net photosynthetic rate (P n ) primarily by promoting stomatal factors, resulting in increased relative growth rates and accelerated soybean seedling growth. High-dose BPA decreases the P n by simultaneously inhibiting stomatal and non-stomatal factors, and this inhibition decreases the relative growth rates further reducing soybean seedling growth. Following the withdrawal of BPA, all of the indices were restored to varying degrees. In conclusion, low-dose BPA increased the P n by promoting stomatal factors while high-dose BPA decreased the P n by simultaneously inhibiting stomatal and non-stomatal factors. These findings provide a model (or, hypothesis) for the effects of BPA on plant photosynthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Temperature effects on respiration and photosynthesis in three diatom-dominated benthic communities

    DEFF Research Database (Denmark)

    Hancke, Kasper; Glud, R.N.

    2004-01-01

    ABSTRACT: Short-term temperature effects on respiration and photosynthesis were investigated in intact diatom-dominated benthic communities, collected at 2 temperate and 1 high-arctic subtidal sites. Areal rates of total (TOE) and diffusive (DOE) O2 exchange were determined from O2-microsensor....... This can be ascribed to changes in physical and biological controls during resuspension. Gross photosynthesis was measured with the light-dark shift method at the 2 temperate sites. Both areal (Pgross) and volumetric (Pgross,vol) rates increased with temperature to an optimum temperature at 12 and 15°C......, with a Q10 for Pgross of 2.2 and 2.6 for the 2 sites, respectively. The gross photosynthesis response could be categorised as psychrotrophic for both sites and no temperature adaptation was observed between the 2 sites. Our measurements document that temperature stimulates heterotrophic activity more than...

  8. Hypergravity of 10 g Changes Plant Growth, Anatomy, Chloroplast Size, and Photosynthesis in the Moss Physcomitrella patens

    Science.gov (United States)

    Takemura, Kaori; Watanabe, Rina; Kameishi, Ryuji; Sakaguchi, Naoya; Kamachi, Hiroyuki; Kume, Atsushi; Karahara, Ichirou; Hanba, Yuko T.; Fujita, Tomomichi

    2017-12-01

    The photosynthetic and anatomical responses of bryophytes to changes in gravity will provide crucial information for estimating how these plant traits evolved to adapt to changes in gravity in land plant history. We performed long-term hypergravity experiments at 10 g for 4 and 8 weeks using the moss Physcomitrella patens with two centrifuges equipped with lighting systems that enable long-term plant growth under hypergravity with irradiance. The aims of this study are (1) to quantify changes in the anatomy and morphology of P. patens, and (2) to analyze the post-effects of hypergravity on photosynthesis by P. patens in relation to these changes. We measured photosynthesis by P. patens for a population of gametophores (e.g., canopy) in Petri dishes and plant culture boxes. Gametophore numbers increased by 9% for a canopy of P. patens, with 24-27% increases in chloroplast sizes (diameter and thickness) in leaf cells. In a canopy of P. patens, the area-based photosynthesis rate ( A canopy) was increased by 57% at 10 g. The increase observed in A canopy was associated with greater plant numbers and chloroplast sizes, both of which involved enhanced CO2 diffusion from the atmosphere to chloroplasts in the canopies of P. patens. These results suggest that changes in gravity are important environmental stimuli to induce changes in plant growth and photosynthesis by P. patens, in which an alteration in chloroplast size is one of the key traits. We are now planning an ISS experiment to investigate the responses of P. patens to microgravity.

  9. In vivo Microscale Measurements of Light and Photosynthesis during Coral Bleaching: Evidence for the Optical Feedback Loop?

    Science.gov (United States)

    Wangpraseurt, Daniel; Holm, Jacob B; Larkum, Anthony W D; Pernice, Mathieu; Ralph, Peter J; Suggett, David J; Kühl, Michael

    2017-01-01

    Climate change-related coral bleaching, i.e., the visible loss of zooxanthellae from the coral host, is increasing in frequency and extent and presents a major threat to coral reefs globally. Coral bleaching has been proposed to involve accelerating light stress of their microalgal endosymbionts via a positive feedback loop of photodamage, symbiont expulsion and excess in vivo light exposure. To test this hypothesis, we used light and O 2 microsensors to characterize in vivo light exposure and photosynthesis of Symbiodinium during a thermal stress experiment. We created tissue areas with different densities of Symbiodinium cells in order to understand the optical properties and light microenvironment of corals during bleaching. Our results showed that in bleached Pocillopora damicornis corals, Symbiodinium light exposure was up to fivefold enhanced relative to healthy corals, and the relationship between symbiont loss and light enhancement was well-described by a power-law function. Cell-specific rates of Symbiodinium gross photosynthesis and light respiration were enhanced in bleached P. damicornis compared to healthy corals, while areal rates of net photosynthesis decreased. Symbiodinium light exposure in Favites sp. revealed the presence of low light microniches in bleached coral tissues, suggesting that light scattering in thick coral tissues can enable photoprotection of cryptic symbionts. Our study provides evidence for the acceleration of in vivo light exposure during coral bleaching but this optical feedback mechanism differs between coral hosts. Enhanced photosynthesis in relation to accelerating light exposure shows that coral microscale optics exerts a key role on coral photophysiology and the subsequent degree of radiative stress during coral bleaching.

  10. The role of photorespiration during the evolution of C4 photosynthesis in the genus Flaveria.

    Science.gov (United States)

    Mallmann, Julia; Heckmann, David; Bräutigam, Andrea; Lercher, Martin J; Weber, Andreas P M; Westhoff, Peter; Gowik, Udo

    2014-06-16

    C4 photosynthesis represents a most remarkable case of convergent evolution of a complex trait, which includes the reprogramming of the expression patterns of thousands of genes. Anatomical, physiological, and phylogenetic and analyses as well as computational modeling indicate that the establishment of a photorespiratory carbon pump (termed C2 photosynthesis) is a prerequisite for the evolution of C4. However, a mechanistic model explaining the tight connection between the evolution of C4 and C2 photosynthesis is currently lacking. Here we address this question through comparative transcriptomic and biochemical analyses of closely related C3, C3-C4, and C4 species, combined with Flux Balance Analysis constrained through a mechanistic model of carbon fixation. We show that C2 photosynthesis creates a misbalance in nitrogen metabolism between bundle sheath and mesophyll cells. Rebalancing nitrogen metabolism requires anaplerotic reactions that resemble at least parts of a basic C4 cycle. Our findings thus show how C2 photosynthesis represents a pre-adaptation for the C4 system, where the evolution of the C2 system establishes important C4 components as a side effect.

  11. Photosynthesis and photosynthetic electron flow in the alpine evergreen species Quercus guyavifolia in winter

    Directory of Open Access Journals (Sweden)

    Wei Huang

    2016-10-01

    Full Text Available Alpine evergreen broadleaf tree species must regularly cope with low night temperatures in winter. However, the effects of low night temperatures on photosynthesis in alpine evergreen broadleaf tree species are unclear. We measured the diurnal photosynthetic parameters before and after cold snap for leaves of Quercus guyavifolia growing in its native habitat at 3290 m. On 11 and 12 December 2013 (before cold snap, stomatal and mesophyll conductances (gs and gm, CO2 assimilation rate (An, and total electron flow through PSII (JPSII at daytime were maintained at high levels. The major action of alternative electron flow was to provide extra ATP for primary metabolisms. On 20 December 2013 (after cold snap, the diurnal values of gs, gm, An and JPSII at daytime largely decreased, mainly due to the large decrease in night air temperature. Meanwhile, the ratio of photorespiration and alternative electron flow to JPSII largely increased on 20 December. Furthermore, the high levels of alternative electron flow were accompanied with low rates of extra ATP production. A quantitative limitation analysis reveals that the gm limitation increased on 20 December with decreased night air temperature. Therefore, the night air temperature was an important determinant of stomatal/mesophyll conductance and photosynthesis. When photosynthesis is inhibited following freezing night temperatures, photorespiration and alternative electron flow are important electron sinks, which support the role of photorespiration and alternative electron flow in photoportection for alpine plants under low temperatures.

  12. Exposure to fentanyl-contaminated heroin and overdose risk among illicit opioid users in Rhode Island: A mixed methods study.

    Science.gov (United States)

    Carroll, Jennifer J; Marshall, Brandon D L; Rich, Josiah D; Green, Traci C

    2017-08-01

    Illicit fentanyl use has become wide spread in the US, causing high rates of overdose deaths among people who use drugs. This study describes patterns and perceptions of fentanyl exposure among opioid users in Rhode Island. A mixed methods study was conducted via questionnaire with a convenience sample of 149 individuals using illicit opioids or misusing prescription opioids in Rhode Island between January and November 2016. Of these, 121 knew of fentanyl and reported known or suspected exposure to fentanyl in the past year. Semi-structured interviews were conducted with the first 47 participants. Study participants were predominantly male (64%) and white (61%). Demographic variables were similar across sample strata. Heroin was the most frequently reported drug of choice (72%). Self-reported exposure to illicit fentanyl in the past year was common (50.4%, n=61). In multivariate models, regular (at least weekly) heroin use was independently associated with known or suspected fentanyl exposure in the past year (adjusted prevalence ratio (APR)=4.07, 95% CI: 1.24-13.3, p=0.020). In interviews, users described fentanyl as unpleasant, potentially deadly, and to be avoided. Participants reporting fentanyl exposure routinely experienced or encountered non-fatal overdose. Heroin users reported limited ability to identify fentanyl in their drugs. Harm reduction strategies used to protect themselves from fentanyl exposure and overdose, included test hits, seeking prescription opioids in lieu of heroin, and seeking treatment with combination buprenorphine/naloxone. Participants were often unsuccessful in accessing structured treatment programs. Among illicit opioid users in Rhode Island, known or suspected fentanyl exposure is common, yet demand for fentanyl is low. Fentanyl-contaminated drugs are generating user interest in effective risk mitigation strategies, including treatment. Responses to the fentanyl epidemic should be informed by the perceptions and experiences of

  13. Pectin Methylesterification Impacts the Relationship between Photosynthesis and Plant Growth.

    Science.gov (United States)

    M Weraduwage, Sarathi; Kim, Sang-Jin; Renna, Luciana; C Anozie, Fransisca; D Sharkey, Thomas; Brandizzi, Federica

    2016-06-01

    Photosynthesis occurs in mesophyll cells of specialized organs such as leaves. The rigid cell wall encapsulating photosynthetic cells controls the expansion and distribution of cells within photosynthetic tissues. The relationship between photosynthesis and plant growth is affected by leaf area. However, the underlying genetic mechanisms affecting carbon partitioning to different aspects of leaf growth are not known. To fill this gap, we analyzed Arabidopsis plants with altered levels of pectin methylesterification, which is known to modulate cell wall plasticity and plant growth. Pectin methylesterification levels were varied through manipulation of cotton Golgi-related (CGR) 2 or 3 genes encoding two functionally redundant pectin methyltransferases. Increased levels of methylesterification in a line over-expressing CGR2 (CGR2OX) resulted in highly expanded leaves with enhanced intercellular air spaces; reduced methylesterification in a mutant lacking both CGR-genes 2 and 3 (cgr2/3) resulted in thin but dense leaf mesophyll that limited CO2 diffusion to chloroplasts. Leaf, root, and plant dry weight were enhanced in CGR2OX but decreased in cgr2/3. Differences in growth between wild type and the CGR-mutants can be explained by carbon partitioning but not by variations in area-based photosynthesis. Therefore, photosynthesis drives growth through alterations in carbon partitioning to new leaf area growth and leaf mass per unit leaf area; however, CGR-mediated pectin methylesterification acts as a primary factor in this relationship through modulation of the expansion and positioning of the cells in leaves, which in turn drive carbon partitioning by generating dynamic carbon demands in leaf area growth and leaf mass per unit leaf area. © 2016 American Society of Plant Biologists. All Rights Reserved.

  14. The social acceptance of artificial photosynthesis: towards a conceptual framework

    Science.gov (United States)

    Sovacool, Benjamin K.; Gross, Allan

    2015-01-01

    Advancements in artificial photosynthesis have the potential to radically transform how societies convert and use energy. Their successful development, however, hinges not only on technical breakthroughs, but also acceptance and adoption by energy users. This article introduces a conceptual framework enabling analysts, planners and even investors to determine environments where artificial photosynthesis may thrive, and those where it may struggle. Drawn from work looking at the barriers and acceptance of solar photovoltaic and wind energy systems, the article proposes that social acceptance has multiple dimensions—socio-political, community and market—that must be met holistically in order for investors and users to embrace new technologies. The article argues that any future market acceptance for artificial photosynthesis will depend upon the prevalence of nine factors, which create conducive environments; the lack of the conditions engenders environments where they will likely be rejected. The conditions are (i) strong institutional capacity; (ii) political commitment; (iii) favourable legal and regulatory frameworks; (iv) competitive installation and/or production costs; (v) mechanisms for information and feedback; (vi) access to financing; (vii) prolific community and/or individual ownership and use; (viii) participatory project siting; and (ix) recognition of externalities or positive public image. PMID:26052424

  15. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs

    NARCIS (Netherlands)

    Klatt, Judith M.; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2S: (i) H2S accelerated the recovery of

  16. Interactive effects of oxygen, carbon dioxide and flow on photosynthesis and respiration in the scleractinian coral Galaxea fascicularis.

    Science.gov (United States)

    Osinga, Ronald; Derksen-Hooijberg, Marlous; Wijgerde, Tim; Verreth, Johan A J

    2017-06-15

    Rates of dark respiration and net photosynthesis were measured for six replicate clonal fragments of the stony coral Galaxea fascicularis (Linnaeus 1767), which were incubated under 12 different combinations of dissolved oxygen (20%, 100% and 150% saturation), dissolved carbon dioxide (9.5 and 19.1 µmol l -1 ) and water flow (1-1.6 versus 4-13 cm s -1 ) in a repeated measures design. Dark respiration was enhanced by increased flow and increased oxygen saturation in an interactive way, which relates to improved oxygen influx into the coral tissue. Oxygen saturation did not influence net photosynthesis: neither hypoxia nor hyperoxia affected net photosynthesis, irrespective of flow and pH, which suggests that hyperoxia does not induce high rates of photorespiration in this coral. Flow and pH had a synergistic effect on net photosynthesis: at high flow, a decrease in pH stimulated net photosynthesis by 14%. These results indicate that for this individual of G. fascicularis , increased uptake of carbon dioxide rather than increased efflux of oxygen explains the beneficial effect of water flow on photosynthesis. Rates of net photosynthesis measured in this study are among the highest ever recorded for scleractinian corals and confirm a strong scope for growth. © 2017. Published by The Company of Biologists Ltd.

  17. Exploring the spatial distribution of light interception and photosynthesis of canopies by means of a functional–structural plant model

    Science.gov (United States)

    Sarlikioti, V.; de Visser, P. H. B.; Marcelis, L. F. M.

    2011-01-01

    Background and Aims At present most process-based models and the majority of three-dimensional models include simplifications of plant architecture that can compromise the accuracy of light interception simulations and, accordingly, canopy photosynthesis. The aim of this paper is to analyse canopy heterogeneity of an explicitly described tomato canopy in relation to temporal dynamics of horizontal and vertical light distribution and photosynthesis under direct- and diffuse-light conditions. Methods Detailed measurements of canopy architecture, light interception and leaf photosynthesis were carried out on a tomato crop. These data were used for the development and calibration of a functional–structural tomato model. The model consisted of an architectural static virtual plant coupled with a nested radiosity model for light calculations and a leaf photosynthesis module. Different scenarios of horizontal and vertical distribution of light interception, incident light and photosynthesis were investigated under diffuse and direct light conditions. Key Results Simulated light interception showed a good correspondence to the measured values. Explicitly described leaf angles resulted in higher light interception in the middle of the plant canopy compared with fixed and ellipsoidal leaf-angle distribution models, although the total light interception remained the same. The fraction of light intercepted at a north–south orientation of rows differed from east–west orientation by 10 % on winter and 23 % on summer days. The horizontal distribution of photosynthesis differed significantly between the top, middle and lower canopy layer. Taking into account the vertical variation of leaf photosynthetic parameters in the canopy, led to approx. 8 % increase on simulated canopy photosynthesis. Conclusions Leaf angles of heterogeneous canopies should be explicitly described as they have a big impact both on light distribution and photosynthesis. Especially, the vertical

  18. Exploring the spatial distribution of light interception and photosynthesis of canopies by means of a functional-structural plant model.

    Science.gov (United States)

    Sarlikioti, V; de Visser, P H B; Marcelis, L F M

    2011-04-01

    At present most process-based models and the majority of three-dimensional models include simplifications of plant architecture that can compromise the accuracy of light interception simulations and, accordingly, canopy photosynthesis. The aim of this paper is to analyse canopy heterogeneity of an explicitly described tomato canopy in relation to temporal dynamics of horizontal and vertical light distribution and photosynthesis under direct- and diffuse-light conditions. Detailed measurements of canopy architecture, light interception and leaf photosynthesis were carried out on a tomato crop. These data were used for the development and calibration of a functional-structural tomato model. The model consisted of an architectural static virtual plant coupled with a nested radiosity model for light calculations and a leaf photosynthesis module. Different scenarios of horizontal and vertical distribution of light interception, incident light and photosynthesis were investigated under diffuse and direct light conditions. Simulated light interception showed a good correspondence to the measured values. Explicitly described leaf angles resulted in higher light interception in the middle of the plant canopy compared with fixed and ellipsoidal leaf-angle distribution models, although the total light interception remained the same. The fraction of light intercepted at a north-south orientation of rows differed from east-west orientation by 10 % on winter and 23 % on summer days. The horizontal distribution of photosynthesis differed significantly between the top, middle and lower canopy layer. Taking into account the vertical variation of leaf photosynthetic parameters in the canopy, led to approx. 8 % increase on simulated canopy photosynthesis. Leaf angles of heterogeneous canopies should be explicitly described as they have a big impact both on light distribution and photosynthesis. Especially, the vertical variation of photosynthesis in canopy is such that the

  19. Connecting Photosynthesis and Cellular Respiration: Preservice Teachers' Conceptions

    Science.gov (United States)

    Brown, Mary H.; Schwartz, Renee S.

    2009-01-01

    The biological processes of photosynthesis and plant cellular respiration include multiple biochemical steps, occur simultaneously within plant cells, and share common molecular components. Yet, learners often compartmentalize functions and specialization of cell organelles relevant to these two processes, without considering the interconnections…

  20. Bibliography of reviews and methods of photosynthesis-85

    Czech Academy of Sciences Publication Activity Database

    Šesták, Zdeněk; Čatský, Jiří

    2002-01-01

    Roč. 39, č. 4 (2002), s. 615-640 ISSN 0300-3604 R&D Projects: GA AV ČR KSK5020115 Institutional research plan: CEZ:AV0Z5038910 Keywords : methods of photosynthesis Subject RIV: EF - Botanics Impact factor: 0.773, year: 2002

  1. In situ temperature relationships of biochemical and stomatal controls of photosynthesis in four lowland tropical tree species.

    Science.gov (United States)

    Slot, Martijn; Winter, Klaus

    2017-12-01

    Net photosynthetic carbon uptake of Panamanian lowland tropical forest species is typically optimal at 30-32 °C. The processes responsible for the decrease in photosynthesis at higher temperatures are not fully understood for tropical trees. We determined temperature responses of maximum rates of RuBP-carboxylation (V CMax ) and RuBP-regeneration (J Max ), stomatal conductance (G s ), and respiration in the light (R Light ) in situ for 4 lowland tropical tree species in Panama. G s had the lowest temperature optimum (T Opt ), similar to that of net photosynthesis, and photosynthesis became increasingly limited by stomatal conductance as temperature increased. J Max peaked at 34-37 °C and V CMax ~2 °C above that, except in the late-successional species Calophyllum longifolium, in which both peaked at ~33 °C. R Light significantly increased with increasing temperature, but simulations with a photosynthesis model indicated that this had only a small effect on net photosynthesis. We found no evidence for Rubisco-activase limitation of photosynthesis. T Opt of V CMax and J Max fell within the observed in situ leaf temperature range, but our study nonetheless suggests that net photosynthesis of tropical trees is more strongly influenced by the indirect effects of high temperature-for example, through elevated vapour pressure deficit and resulting decreases in stomatal conductance-than by direct temperature effects on photosynthetic biochemistry and respiration. © 2017 John Wiley & Sons Ltd.

  2. Applying photosynthesis research to increase crop yields

    Science.gov (United States)

    Clayton C. Black; Shi-Jean S. Sung; Kristina Toderich; Pavel Yu Voronin

    2010-01-01

    This account is dedicated to Dr. Guivi Sanadze for his career long devotion to science and in recognition of his discovery of isoprene emission by trees during photosynthesis. Investigations on the emission of isoprene and other monoterpenes now have been extended globally to encompass other terrestrial vegetation, algae, waters, and marine life in the world's...

  3. Photosynthate supply and utilization in alfalfa: a developmental shift from a source to a sink limitation of photosynthesis

    International Nuclear Information System (INIS)

    Baysdorfer, C.; Bassham, J.A.

    1985-01-01

    Long-term carbon dioxide enrichment, 14 CO 2 feeding, and partial defoliation were employed as probes to investigate source/sink limitations of photosynthesis during the development of symbiotically grown alfalfa. In the mature crop, long-term CO 2 enrichment does not affect the rates of net photosynthesis, relative growth, 14 C export to nonphotosynthetic organs, or the rates of 14 C label incorporation into leaf sucrose, starch, or malate. The rate of glycolate labeling is, however, substantially reduced under these conditions. When the mature crop was partially defoliated, a considerable increase in net photosynthesis occurred in the remaining leaves. In the seedling crop, long-term CO 2 enrichment increased dry matter accumulation, primarily as a result of increases in leaf starch content. Although the higher rates of starch synthesis are not maintained, the growth enhancement of the enriched plants persisted throughout the experimental period. These results imply a source limitation of seedling photosynthesis and a sink limitation of photosynthesis in more mature plants. Consequently, both the supply and the utilization of photosynthate may limit seasonal photosynthesis in alfalfa

  4. Automated photosynthesis of 11C-glucose

    International Nuclear Information System (INIS)

    Ishiwata, K.; Monma, M.; Iwata, R.; Ido, T.

    1982-01-01

    Glucose and fructose, labelled with 11 C, were produced by passing 11 CO 2 into an evacuated chamber containing spinach leaves. Photosynthesis was carried out by day light lamp illumination. 75-95% of the 11 CO 2 was absorbed by the leaves and the radioactivity in the leaves was extracted in ethanol as sugars. Radiochemical purity was determined by HPLC. The automated system was controlled by timers. (U.K.)

  5. Significance of cold-season respiration and photosynthesis in a subarctic heath ecosystem in Northern Sweden

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, Andreas; Jonasson, S.

    2007-01-01

    While substantial cold-season respiration has been documented in most arctic and alpine ecosystems in recent years, the significance of cold-season photosynthesis in these biomes is still believed to be small. In a mesic, subartic heath during both the cold and warm season, we measured in situ...... ecosystem respiration and photosynthesis with a chamber technique at ambient conditions and at artificially, increased frequency of freeze-thaw (FT) cycles during fall and spring. We fitted the measured ecosystem exchange rates to respiration and photosynthesis models with R-2-values ranging from 0.81 to 0.......85. As expected, estimated cold-season (October, November, April and May) respiration was significant and accounted for at least 22% of the annual respiratory CO2 flux. More surprisingly, estimated photosynthesis during this period accounted for up to 19% of the annual gross CO2 uptake, suggesting that cold...

  6. Suppression of nighttime sap flux with lower stem photosynthesis in Eucalyptus trees.

    Science.gov (United States)

    Gao, Jianguo; Zhou, Juan; Sun, Zhenwei; Niu, Junfeng; Zhou, Cuiming; Gu, Daxing; Huang, Yuqing; Zhao, Ping

    2016-04-01

    It is widely accepted that substantial nighttime sap flux (J s,n) or transpiration (E) occurs in most plants, but the physiological implications are poorly known. It has been hypothesized that J s,n or E serves to enhance nitrogen uptake or deliver oxygen; however, no clear evidence is currently available. In this study, sap flux (J s) in Eucalyptus grandis × urophylla with apparent stem photosynthesis was measured, including control trees which were covered by aluminum foil (approximately 1/3 of tree height) to block stem photosynthesis. We hypothesized that the nighttime water flux would be suppressed in trees with lower stem photosynthesis. The results showed that the green tissue degraded after 3 months, demonstrating a decrease in stem photosynthesis. The daytime J s decreased by 21.47%, while J s,n decreased by 12.03% in covered trees as compared to that of control, and the difference was statistically significant (P photosynthesis in covered trees. Predawn (ψ pd) of covered trees was marginally higher than that of control while lower at predawn stomatal conductance (g s), indicating a suppressed water flux in covered trees. There was no difference in leaf carbon content and δ(13)C between the two groups, while leaf nitrogen content and δ(15)N were significantly higher in covered trees than that of the control (P < 0.05), indicating that J s,n was not used for nitrogen uptake. These results suggest that J s,n may act as an oxygen pathway since green tissue has a higher respiration or oxygen demand than non-green tissue. Thus, this study demonstrated the physiological implications of J s,n and the possible benefits of nighttime water use or E by the tree.

  7. Siting high-level nuclear waste repositories: A progress report for Rhode Island

    International Nuclear Information System (INIS)

    Frohlich, R.K.; Vild, B.F.

    1986-03-01

    In this booklet, we will not try to argue the pros and cons of nuclear power or weapons production. We will focus instead on the issue of nuclear waste disposal. With the passage of the Nuclear Waste Policy Act (NWPA) of 1982, the US Congress and the President charged federal and state regulators with the responsibility of settling that issue by the end of this century - with extensive public involvement. This booklet, now in its second printing, is designed to explain the nature of ''high-level'' nuclear waste, the essential criteria for its safe and permanent disposal, and Rhode Island's participation in the federal repository program. It has been funded from a USDOE grant derived from a utility-financed Nuclear Waste Fund established under the NWPA. 17 refs., 10 figs., 2 tabs

  8. Association between photosynthesis and contrasting features of minor veins in leaves of summer annuals loading phloem via symplastic versus apoplastic routes.

    Science.gov (United States)

    Muller, Onno; Cohu, Christopher M; Stewart, Jared J; Protheroe, Johanna A; Demmig-Adams, Barbara; Adams, William W

    2014-09-01

    Foliar vascular anatomy and photosynthesis were evaluated for a number of summer annual species that either load sugars into the phloem via a symplastic route (Cucumis sativus L. cv. Straight Eight; Cucurbita pepo L. cv. Italian Zucchini Romanesco; Citrullus lanatus L. cv. Faerie Hybrid; Cucurbita pepo L. cv. Autumn Gold) or an apoplastic route (Nicotiana tabacum L.; Solanum lycopersicum L. cv. Brandywine; Gossypium hirsutum L.; Helianthus annuus L. cv. Soraya), as well as winter annual apoplastic loaders (Spinacia oleracea L. cv. Giant Nobel; Arabidopsis thaliana (L.) Heynhold Col-0, Swedish and Italian ecotypes). For all summer annuals, minor vein cross-sectional xylem area and tracheid number as well as the ratio of phloem loading cells to phloem sieve elements, each when normalized for foliar vein density (VD), was correlated with photosynthesis. These links presumably reflect (1) the xylem's role in providing water to meet foliar transpirational demand supporting photosynthesis and (2) the importance of the driving force of phloem loading as well as the cross-sectional area for phloem sap flux to match foliar photosynthate production. While photosynthesis correlated with the product of VD and cross-sectional phloem cell area among symplastic loaders, photosynthesis correlated with the product of VD and phloem cell number per vein among summer annual apoplastic loaders. Phloem cell size has thus apparently been a target of selection among symplastic loaders (where loading depends on enzyme concentration within loading cells) versus phloem cell number among apoplastic loaders (where loading depends on membrane transporter numbers). © 2014 Scandinavian Plant Physiology Society.

  9. Synthesis of Phenolics and Flavonoids in Ginger (Zingiber officinale Roscoe and Their Effects on Photosynthesis Rate

    Directory of Open Access Journals (Sweden)

    Asmah Rahmat

    2010-11-01

    Full Text Available The relationship between phenolics and flavonoids synthesis/accumulation and photosynthesis rate was investigated for two Malaysian ginger (Zingiber officinale varieties grown under four levels of glasshouse light intensity, namely 310, 460, 630 and 790 μmol m−2s−1. High performance liquid chromatography (HPLC was employed to identify and quantify the polyphenolic components. The results of HPLC analysis indicated that synthesis and partitioning of quercetin, rutin, catechin, epicatechin and naringenin were high in plants grown under 310 µmol m−2s−1. The average value of flavonoids synthesis in leaves for both varieties increased (Halia Bentong 26.1%; Halia Bara 19.5% when light intensity decreased. Photosynthetic rate and plant biomass increased in both varieties with increasing light intensity. More specifically, a high photosynthesis rate (12.25 µmol CO2 m−2s−1 in Halia Bara and plant biomass (79.47 g in Halia Bentong were observed at 790 µmol m−2s−1. Furthermore, plants with the lowest rate of photosynthesis had highest flavonoids content. Previous studies have shown that quercetin inhibits and salicylic acid induces the electron transport rate in photosynthesis photosystems. In the current study, quercetin was an abundant flavonoid in both ginger varieties. Moreover, higher concentration of quercetin (1.12 mg/g dry weight was found in Halia Bara leaves grown under 310 µmol m−2s−1 with a low photosynthesis rate. Furthermore, a high content of salicylic acid (0.673 mg/g dry weight was detected in Halia Bara leaves exposed under 790 µmol m−2s−1 with a high photosynthesis rate. No salicylic acid was detected in gingers grown under 310 µmol m−2s−1. Ginger is a semi-shade loving plant that does not require high light intensity for photosynthesis. Different photosynthesis rates at different light intensities may be related to the absence or presence of some flavonoid and phenolic compounds.

  10. Synthesis of Phenolics and Flavonoids in Ginger (Zingiber officinale Roscoe) and Their Effects on Photosynthesis Rate

    Science.gov (United States)

    Ghasemzadeh, Ali; Jaafar, Hawa Z. E.; Rahmat, Asmah

    2010-01-01

    The relationship between phenolics and flavonoids synthesis/accumulation and photosynthesis rate was investigated for two Malaysian ginger (Zingiber officinale) varieties grown under four levels of glasshouse light intensity, namely 310, 460, 630 and 790 μmol m−2s−1. High performance liquid chromatography (HPLC) was employed to identify and quantify the polyphenolic components. The results of HPLC analysis indicated that synthesis and partitioning of quercetin, rutin, catechin, epicatechin and naringenin were high in plants grown under 310 μmol m−2s−1. The average value of flavonoids synthesis in leaves for both varieties increased (Halia Bentong 26.1%; Halia Bara 19.5%) when light intensity decreased. Photosynthetic rate and plant biomass increased in both varieties with increasing light intensity. More specifically, a high photosynthesis rate (12.25 μmol CO2 m−2s−1 in Halia Bara) and plant biomass (79.47 g in Halia Bentong) were observed at 790 μmol m−2s−1. Furthermore, plants with the lowest rate of photosynthesis had highest flavonoids content. Previous studies have shown that quercetin inhibits and salicylic acid induces the electron transport rate in photosynthesis photosystems. In the current study, quercetin was an abundant flavonoid in both ginger varieties. Moreover, higher concentration of quercetin (1.12 mg/g dry weight) was found in Halia Bara leaves grown under 310 μmol m−2s−1 with a low photosynthesis rate. Furthermore, a high content of salicylic acid (0.673 mg/g dry weight) was detected in Halia Bara leaves exposed under 790 μmol m−2s−1 with a high photosynthesis rate. No salicylic acid was detected in gingers grown under 310 μmol m−2s−1. Ginger is a semi-shade loving plant that does not require high light intensity for photosynthesis. Different photosynthesis rates at different light intensities may be related to the absence or presence of some flavonoid and phenolic compounds. PMID:21151455

  11. Comparative proteomic analysis reveals the positive effect of exogenous spermidine on photosynthesis and salinity tolerance in cucumber seedlings.

    Science.gov (United States)

    Sang, Ting; Shan, Xi; Li, Bin; Shu, Sheng; Sun, Jin; Guo, Shirong

    2016-08-01

    Our results based on proteomics data and physiological alterations proposed the putative mechanism of exogenous Spd enhanced salinity tolerance in cucumber seedlings. Current studies showed that exogenous spermidine (Spd) could alleviate harmful effects of salinity. It is important to increase our understanding of the beneficial physiological responses of exogenous Spd treatment, and to determine the molecular responses underlying these responses. Here, we combined a physiological analysis with iTRAQ-based comparative proteomics of cucumber (Cucumis sativus L.) leaves, treated with 0.1 mM exogenous Spd, 75 mM NaCl and/or exogenous Spd. A total of 221 differentially expressed proteins were found and involved in 30 metabolic pathways, such as photosynthesis, carbohydrate metabolism, amino acid metabolism, stress response, signal transduction and antioxidant. Based on functional classification of the differentially expressed proteins and the physiological responses, we found cucumber seedlings treated with Spd under salt stress had higher photosynthesis efficiency, upregulated tetrapyrrole synthesis, stronger ROS scavenging ability and more protein biosynthesis activity than NaCl treatment, suggesting that these pathways may promote salt tolerance under high salinity. This study provided insights into how exogenous Spd protects photosynthesis and enhances salt tolerance in cucumber seedlings.

  12. Chloroplastic and stomatal aspects of ozone-induced reduction of net photosynthesis in plants

    Energy Technology Data Exchange (ETDEWEB)

    Torsethaugen, Gro

    1998-09-01

    The present thesis relates to ozone-induced reduction of photosynthesis in plants. As a photochemical oxidant O{sub 3} is formed by the interaction of hydrocarbons, nitrogen oxides and oxygen in sunlight. Ozone (O{sub 3}) is the most phytotoxic of all the air pollutants and is known to reduce plant growth and net photosynthesis, cause stomatal closure, induce visible injury, accelerate senescence and induce or inhibit transcription of a variety of genes with a corresponding increase/decrease in protein products. The underlying cellular mechanisms for many of these changes are unknown. Following fields are investigated: Ozone-induced reduction of net photosynthesis; ozone and the photosynthetic apparatus in the chloroplasts; ozone and stomata; ozone effects on plant membranes; protection against ozone injury in plants. 249 refs., 22 figs., 4 tabs.

  13. The role of photorespiration during the evolution of C4 photosynthesis in the genus Flaveria

    Science.gov (United States)

    Mallmann, Julia; Heckmann, David; Bräutigam, Andrea; Lercher, Martin J; Weber, Andreas PM; Westhoff, Peter; Gowik, Udo

    2014-01-01

    C4 photosynthesis represents a most remarkable case of convergent evolution of a complex trait, which includes the reprogramming of the expression patterns of thousands of genes. Anatomical, physiological, and phylogenetic and analyses as well as computational modeling indicate that the establishment of a photorespiratory carbon pump (termed C2 photosynthesis) is a prerequisite for the evolution of C4. However, a mechanistic model explaining the tight connection between the evolution of C4 and C2 photosynthesis is currently lacking. Here we address this question through comparative transcriptomic and biochemical analyses of closely related C3, C3–C4, and C4 species, combined with Flux Balance Analysis constrained through a mechanistic model of carbon fixation. We show that C2 photosynthesis creates a misbalance in nitrogen metabolism between bundle sheath and mesophyll cells. Rebalancing nitrogen metabolism requires anaplerotic reactions that resemble at least parts of a basic C4 cycle. Our findings thus show how C2 photosynthesis represents a pre-adaptation for the C4 system, where the evolution of the C2 system establishes important C4 components as a side effect. DOI: http://dx.doi.org/10.7554/eLife.02478.001 PMID:24935935

  14. Physiological and Proteomics Analyses Reveal Low-Phosphorus Stress Affected the Regulation of Photosynthesis in Soybean.

    Science.gov (United States)

    Chu, Shanshan; Li, Hongyan; Zhang, Xiangqian; Yu, Kaiye; Chao, Maoni; Han, Suoyi; Zhang, Dan

    2018-06-06

    Previous studies have revealed a significant genetic relationship between phosphorus (P)-efficiency and photosynthesis-related traits in soybean. In this study, we used proteome profiling in combination with expression analysis, biochemical investigations, and leaf ultrastructural analysis to identify the underlying physiological and molecular responses. The expression analysis and ultrastructural analysis showed that the photosynthesis key genes were decreased at transcript levels and the leaf mesophyll and chloroplast were severely damaged after low-P stress. Approximately 55 protein spots showed changes under low-P condition by mass spectrometry, of which 17 were involved in various photosynthetic processes. Further analysis revealed the depression of photosynthesis caused by low-P stress mainly involves the regulation of leaf structure, adenosine triphosphate (ATP) synthesis, absorption and transportation of CO₂, photosynthetic electron transport, production of assimilatory power, and levels of enzymes related to the Calvin cycle. In summary, our findings indicated that the existence of a stringent relationship between P supply and the genomic control of photosynthesis in soybean. As an important strategy to protect soybean photosynthesis, P could maintain the stability of cell structure, up-regulate the enzymes’ activities, recover the process of photosystem II (PSII), and induce the expression of low-P responsive genes and proteins.

  15. Nutrient, suspended sediment, and trace element loads in the Blackstone River Basin in Massachusetts and Rhode Island, 2007 to 2009

    Science.gov (United States)

    Zimmerman, Marc J.; Waldron, Marcus C.; DeSimone, Leslie A.

    2015-01-01

    Nutrients, suspended sediment, and trace element loads in the Blackstone River and selected tributaries were estimated from composite water-quality samples in order to better understand the distribution and sources of these constituents in the river basin. The flow-proportional composite water-quality samples were collected during sequential 2-week periods at six stations along the river’s main stem, at three stations on tributaries, and at four wastewater treatment plants in the Massachusetts segment of the basin from June 2007 to September 2009. Samples were collected at an additional station on the Blackstone River near the mouth in Pawtucket, Rhode Island, from September 2008 to September 2009. The flow-proportional composite samples were used to estimate average daily loads during the sampling periods; annual loads for water years 2008 and 2009 also were estimated for the monitoring station on the Blackstone River near the Massachusetts-Rhode Island border. The effects of hydrologic conditions and net attenuation of nitrogen were investigated for loads in the Massachusetts segment of the basin. Sediment resuspension and contaminant loading dynamics were evaluated in two Blackstone River impoundments, the former Rockdale Pond (a breached impoundment) and Rice City Pond.

  16. Acclimation of biochemical and diffusive components of photosynthesis in rice, wheat and maize to heat and water deficit: implications for modeling photosynthesis

    Directory of Open Access Journals (Sweden)

    Juan Alejandro Perdomo

    2016-11-01

    Full Text Available The impact of the combined effects of heat stress, increased vapor pressure deficit (VPD and water deficit on the physiology of major crops needs to be better understood to help identifying the expected negative consequences of climate change and heat waves on global agricultural productivity. To address this issue, rice, wheat and maize plants were grown under control temperature (CT, 25°C, VPD 1.8 kPa, and a high temperature (HT, 38°C, VPD 3.5 kPa, both under well-watered (WW and water deficit (WD conditions. Gas-exchange measurements showed that, in general, WD conditions affected the leaf conductance to CO2, while growth at HT had a more marked effect on the biochemistry of photosynthesis. When combined, HT and WD had an additive effect in limiting photosynthesis. The negative impacts of the imposed treatments on the processes governing leaf gas-exchange were species-dependent. Wheat presented a higher sensitivity while rice and maize showed a higher acclimation potential to increased temperature. Rubisco and PEPC kinetic constants determined in vitro at 25°C and 38°C were used to estimate Vcmax, Jmax and Vpmax in the modeling of C3 and C4 photosynthesis. The results here obtained reiterate the need to use species-specific and temperature-specific values for Rubisco and PEPC kinetic constants for a precise parameterization of the photosynthetic response to changing environmental conditions in different crop species.

  17. Elevated Temperature and CO2 Stimulate Late-Season Photosynthesis But Impair Cold Hardening in Pine.

    Science.gov (United States)

    Chang, Christine Y; Fréchette, Emmanuelle; Unda, Faride; Mansfield, Shawn D; Ensminger, Ingo

    2016-10-01

    Rising global temperature and CO 2 levels may sustain late-season net photosynthesis of evergreen conifers but could also impair the development of cold hardiness. Our study investigated how elevated temperature, and the combination of elevated temperature with elevated CO 2 , affected photosynthetic rates, leaf carbohydrates, freezing tolerance, and proteins involved in photosynthesis and cold hardening in Eastern white pine (Pinus strobus). We designed an experiment where control seedlings were acclimated to long photoperiod (day/night 14/10 h), warm temperature (22°C/15°C), and either ambient (400 μL L -1 ) or elevated (800 μmol mol -1 ) CO 2 , and then shifted seedlings to growth conditions with short photoperiod (8/16 h) and low temperature/ambient CO 2 (LTAC), elevated temperature/ambient CO 2 (ETAC), or elevated temperature/elevated CO 2 (ETEC). Exposure to LTAC induced down-regulation of photosynthesis, development of sustained nonphotochemical quenching, accumulation of soluble carbohydrates, expression of a 16-kD dehydrin absent under long photoperiod, and increased freezing tolerance. In ETAC seedlings, photosynthesis was not down-regulated, while accumulation of soluble carbohydrates, dehydrin expression, and freezing tolerance were impaired. ETEC seedlings revealed increased photosynthesis and improved water use efficiency but impaired dehydrin expression and freezing tolerance similar to ETAC seedlings. Sixteen-kilodalton dehydrin expression strongly correlated with increases in freezing tolerance, suggesting its involvement in the development of cold hardiness in P. strobus Our findings suggest that exposure to elevated temperature and CO 2 during autumn can delay down-regulation of photosynthesis and stimulate late-season net photosynthesis in P. strobus seedlings. However, this comes at the cost of impaired freezing tolerance. Elevated temperature and CO 2 also impaired freezing tolerance. However, unless the frequency and timing of extreme low

  18. NO MECHANISTIC DEPENDENCE OF PHOTOSYNTHESIS ON CALCIFICATION IN THE COCCOLITHOPHORID EMILIANIA HUXLEYI (HAPTOPHYTA)(1).

    Science.gov (United States)

    Leonardos, Nikos; Read, Betsy; Thake, Brenda; Young, Jeremy R

    2009-10-01

    There is still considerable uncertainty about the relationship between calcification and photosynthesis. It has been suggested that since calcification in coccolithophorids is an intracellular process that releases CO2 , it enhances photosynthesis in a manner analogous to a carbon-concentrating mechanism (CCM). The ubiquitous, bloom-forming, and numerically abundant coccolithophorid Emiliania huxleyi (Lohmann) W. W. Hay et H. Mohler was studied in nutrient-replete, pH and [CO2 ] controlled, continuous cultures (turbidostats) under a range of [Ca(2+) ] from 0 to 9 mM. We examined the long-term, fully acclimated photosynthesis-light responses and analyzed the crystalline structure of the coccoliths using SEM. The E. huxleyi cells completely lost their coccosphere when grown in 0 [Ca(2+) ], while thin, undercalcified and brittle coccoliths were evident at 1 mM [Ca(2+) ]. Coccoliths showed increasing levels of calcification with increasing [Ca(2+) ]. More robust coccoliths were noted, with no discernable differences in coccolith morphology when the cells were grown in either 5 or 9 mM (ambient seawater) [Ca(2+) ]. In contrast to calcification, photosynthesis was not affected by the [Ca(2+) ] in the media. Cells showed no correlation of their light-dependent O2 evolution with [Ca(2+) ], and in all [Ca(2+) ]-containing turbidostats, there were no significant differences in growth rate. The results show unequivocally that as a process, photosynthesis in E. huxleyi is mechanistically independent from calcification. © 2009 Phycological Society of America.

  19. Elevated Temperature and CO2 Stimulate Late-Season Photosynthesis But Impair Cold Hardening in Pine[OPEN

    Science.gov (United States)

    2016-01-01

    Rising global temperature and CO2 levels may sustain late-season net photosynthesis of evergreen conifers but could also impair the development of cold hardiness. Our study investigated how elevated temperature, and the combination of elevated temperature with elevated CO2, affected photosynthetic rates, leaf carbohydrates, freezing tolerance, and proteins involved in photosynthesis and cold hardening in Eastern white pine (Pinus strobus). We designed an experiment where control seedlings were acclimated to long photoperiod (day/night 14/10 h), warm temperature (22°C/15°C), and either ambient (400 μL L−1) or elevated (800 μmol mol−1) CO2, and then shifted seedlings to growth conditions with short photoperiod (8/16 h) and low temperature/ambient CO2 (LTAC), elevated temperature/ambient CO2 (ETAC), or elevated temperature/elevated CO2 (ETEC). Exposure to LTAC induced down-regulation of photosynthesis, development of sustained nonphotochemical quenching, accumulation of soluble carbohydrates, expression of a 16-kD dehydrin absent under long photoperiod, and increased freezing tolerance. In ETAC seedlings, photosynthesis was not down-regulated, while accumulation of soluble carbohydrates, dehydrin expression, and freezing tolerance were impaired. ETEC seedlings revealed increased photosynthesis and improved water use efficiency but impaired dehydrin expression and freezing tolerance similar to ETAC seedlings. Sixteen-kilodalton dehydrin expression strongly correlated with increases in freezing tolerance, suggesting its involvement in the development of cold hardiness in P. strobus. Our findings suggest that exposure to elevated temperature and CO2 during autumn can delay down-regulation of photosynthesis and stimulate late-season net photosynthesis in P. strobus seedlings. However, this comes at the cost of impaired freezing tolerance. Elevated temperature and CO2 also impaired freezing tolerance. However, unless the frequency and timing of extreme low

  20. significance of rice sheath photosynthesis: yield determination by c ...

    African Journals Online (AJOL)

    ACSS

    1State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, P.R. China. 2School of ... for contribution rates of sheath photosynthesis to economical yield. ..... related processes during ripening in rice plants.

  1. Aerobic Anoxygenic Photosynthesis Is Commonly Present within the Genus Limnohabitans.

    Science.gov (United States)

    Kasalický, Vojtěch; Zeng, Yonghui; Piwosz, Kasia; Šimek, Karel; Kratochvilová, Hana; Koblížek, Michal

    2018-01-01

    The genus Limnohabitans ( Comamonadaceae , Betaproteobacteria ) is a common and a highly active component of freshwater bacterioplanktonic communities. To date, the genus has been considered to contain only heterotrophic species. In this study, we detected the photosynthesis genes pufLM and bchY in 28 of 46 strains from three Limnohabitans lineages. The pufM sequences obtained are very closely related to environmental pufM sequences detected in various freshwater habitats, indicating the ubiquity and potential importance of photoheterotrophic Limnohabitans in nature. Additionally, we sequenced and analyzed the genomes of 5 potentially photoheterotrophic Limnohabitans strains, to gain further insights into their phototrophic capacity. The structure of the photosynthesis gene cluster turned out to be highly conserved within the genus Limnohabitans and also among all potentially photosynthetic Betaproteobacteria strains. The expression of photosynthetic complexes was detected in a culture of Limnohabitans planktonicus II-D5 T using spectroscopic and pigment analyses. This was further verified by a novel combination of infrared microscopy and fluorescent in situ hybridization. IMPORTANCE The data presented document that the capacity to perform anoxygenic photosynthesis is common among the members of the genus Limnohabitans , indicating that they may have a novel role in freshwater habitats. Copyright © 2017 American Society for Microbiology.

  2. 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.

  3. Radio photosynthesis of some 14 C-labelled sugars using the unicellular green alga scenedesmus ACUTUS

    International Nuclear Information System (INIS)

    Barakat, M.F.; Farag, A.N.; Ragab, M.T.; El-Fouly, M.M.; El-Baz, F.K.

    1993-01-01

    Radiosynthesis has been carried out using the unicellular green alga scenedesmus acutus together with Na H 14 CO 3 solution as a carbon-14 source, in an ordinary photosynthesis chamber. The process is more easier and less laborious than the techniques involving the use of gaseous 14 CO 2 in a tight photosynthesis chamber. Uniformly labelled 14 C-glucose, 14 C-fructose and 14 C-sucrose have been prepared with specific activities of several micro curies per milli mole. The specific activity of the products was found to increase on increasing the photosynthesis time or the initial activity of the Na H 14 CO 3 solution used. 3 tabs

  4. Bibliography of reviews and methods of photosynthesis - 88

    Czech Academy of Sciences Publication Activity Database

    Šesták, Zdeněk; Čatský, Jiří

    2004-01-01

    Roč. 42, č. 4 (2004), s. 619-640 ISSN 0300-3604 R&D Projects: GA ČR GA206/97/0120 Institutional research plan: CEZ:AV0Z5038910 Keywords : Bibliographic survey * processes of photosynthesis * accumulation of energy Subject RIV: EF - Botanics Impact factor: 0.734, year: 2004

  5. Dynamics of photosynthesis in Eichhornia crassipes Solms of ...

    African Journals Online (AJOL)

    2009-11-14

    With LI-6400 portable photosynthesis system, the photosynthetic characteristics of artificially cultured Eichhornia crassipes in Jiangsu, China, were monitored from June 1 to November 14, 2009. Both the net photosynthetic rate (Pn) in different positions and light and temperature-response curves of the top fourth leaf were ...

  6. 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

  7. Understanding of photosynthesis among students of biology and non-biology programmes of study

    OpenAIRE

    Lekan, Erika

    2016-01-01

    Photosynthesis is one of the most important processes on Earth, thus knowing at least its basic principles is essential. In Slovenia, the students become acquainted with these principles in the fifth form of elementary school. Due to the complexity of the photosynthesis process, the students hold misconceptions about it since the very beginning of the learning process. Due to several factors and reasons, these misconceptions persist throughout the secondary school and university studies. ...

  8. Plants growth, water relations and photosynthesis of two bean ...

    African Journals Online (AJOL)

    ... almost all physiological activities were suppressed. The superiority of the genotype Tema against Djadida genotype was attributed to quantitative rather than qualitative physiological response differences. Keywords: Salinity, fluridone, bean, growth, photosynthesis, stomatal conductance. African Journal of Biotechnology ...

  9. Areas contributing recharge to production wells and effects of climate change on the groundwater system in the Chipuxet River and Chickasheen Brook Basins, Rhode Island

    Science.gov (United States)

    Friesz, Paul J.; Stone, Janet R.

    2015-01-01

    The Chipuxet River and Chickasheen Brook Basins in southern Rhode Island are an important water resource for public and domestic supply, irrigation, recreation, and aquatic habitat. The U.S. Geological Survey, in cooperation with the Rhode Island Department of Health, began a study in 2012 as part of an effort to protect the source of water to six large-capacity production wells that supply drinking water and to increase understanding of how climate change might affect the water resources in the basins. Soil-water-balance and groundwater-flow models were developed to delineate the areas contributing recharge to the wells and to quantify the hydrologic response to climate change. Surficial deposits of glacial origin ranging from a few feet to more than 200 feet thick overlie bedrock in the 24.4-square mile study area. These deposits comprise a complex and productive aquifer system.

  10. Promotion of Cyclic Electron Transport Around Photosystem I with the Development of C4 Photosynthesis.

    Science.gov (United States)

    Munekage, Yuri Nakajima; Taniguchi, Yukimi Y

    2016-05-01

    C4 photosynthesis is present in approximately 7,500 species classified into 19 families, including monocots and eudicots. In the majority of documented cases, a two-celled CO2-concentrating system that uses a metabolic cycle of four-carbon compounds is employed. C4 photosynthesis repeatedly evolved from C3 photosynthesis, possibly driven by the survival advantages it bestows in the hot, often dry, and nutrient-poor soils of the tropics and subtropics. The development of the C4 metabolic cycle greatly increased the ATP demand in chloroplasts during the evolution of malic enzyme-type C4 photosynthesis, and the additional ATP required for C4 metabolism may be produced by the cyclic electron transport around PSI. Recent studies have revealed the nature of cyclic electron transport and the elevation of its components during C4 evolution. In this review, we discuss the energy requirements of C3 and C4 photosynthesis, the current model of cyclic electron transport around PSI and how cyclic electron transport is promoted during C4 evolution using studies on the genus Flaveria, which contains a number of closely related C3, C4 and C3-C4 intermediate species. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  11. First chelonian eggs and carapace fragments from the Pliocene of Rhodes, Greece

    DEFF Research Database (Denmark)

    Mueller-Töwe, Inken J.; Kjeldahl-Vallon, Tina A.; Milàn, Jesper

    2011-01-01

    Well-preserved fossil eggs and eggshell fragments from the Pliocene Apolakkia Formation of Rhodes (Greece) are described. The eggs were found in-situ in a clutch. They are sub-spherical with lengths of 53-60 mm and widths of about 40 mm. All eggs are diagenetically compressed and their original...... diameters are estimated at 45-50 mm. The eggshells are 0.3-0.5 mm thick, partly recrystallized, but widely still aragonitic. They consist of needle-like crystals that form individual shell units. A few pores are preserved between these shell units. This shell-structure allows assignment to chelonian eggs...... in the oofamily Testudoolithidae and the oogenus Testudolithus. The external morphology, microstructure and mineralogical composition of the eggshells show close resemblance to eggs of the extant tortoise Geochelone elephantopus. Together with a small association of turtle carapace fragments from the same...

  12. Comparative sensitivity of photosynthesis and translocation to sulfur dioxide damage in Phaseolus vulgaris L

    International Nuclear Information System (INIS)

    Noyes, R.D.

    1978-01-01

    The inhibiting effect of sulfur dioxide on photosynthesis in a mature bean leaf and, simultaneously, on the rate of carbohydrate translocation from this same leaf has been examined. The results show a reduction of 0, 13, and 73% in net photosynthesis and 39, 44, and 69% in translocation, at concentrations of 0.1, 1, and 3 ppm sulfur dioxide, respectively. The inhibition of translocation at 0.1 ppm sulfur dioxide without any accompanying inhibition of net photosynthesis indicates that translocation is considerably more sensitive to sulfur dioxide damage. The mechanism of translocation inhibition at 1 ppm sulfur dioxide or less is shown to be independent of photosynthetic inhibition. Whereas, it is suggested that at higher concentrations significant inhibition of photosynthesis causes an additive reduction of translocation due to reduced levels of transport sugars. Autoradiograms of 14 C-labeled source leaves indicate that one possible mechanism of sulfur dioxide damage to translocation is the inhibition of sieve-tube loading. Inhibition of phloem translocation at common ambient levels (0.1 ppm) of sulfur dioxide is important to the overall growth and yield of major agricultural crops sensitive to sulfur dioxide

  13. Estimating Net Photosynthesis of Biological Soil Crusts in the Atacama Using Hyperspectral Remote Sensing

    Directory of Open Access Journals (Sweden)

    Lukas W. Lehnert

    2018-06-01

    Full Text Available Biological soil crusts (BSC encompassing green algae, cyanobacteria, lichens, bryophytes, heterotrophic bacteria and microfungi are keystone species in arid environments because of their role in nitrogen- and carbon-fixation, weathering and soil stabilization, all depending on the photosynthesis of the BSC. Despite their importance, little is known about the BSCs of the Atacama Desert, although especially crustose chlorolichens account for a large proportion of biomass in the arid coastal zone, where photosynthesis is mainly limited due to low water availability. Here, we present the first hyperspectral reflectance data for the most wide-spread BSC species of the southern Atacama Desert. Combining laboratory and field measurements, we establish transfer functions that allow us to estimate net photosynthesis rates for the most common BSC species. We found that spectral differences among species are high, and differences between the background soil and the BSC at inactive stages are low. Additionally, we found that the water absorption feature at 1420 nm is a more robust indicator for photosynthetic activity than the chlorophyll absorption bands. Therefore, we conclude that common vegetation indices must be taken with care to analyze the photosynthesis of BSC with multispectral data.

  14. Relationships between net photosynthesis and foliar nitrogen concentrations in a loblobby pine forest ecosystem grown in elevated atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Springer, C. J.; Thomas, R. B.; Delucia, E. H.

    2005-01-01

    The effects of elevated carbon dioxide concentration on the relationship between light-saturated net photosynthesis and area-based foliar nitrogen concentration in the canopy of a loblobby pine forest at the Duke Forest FACE experiment was examined. Two overstory and four understory tree species were examined at their growth carbon dioxide concentrations during the early summer and late summer of 1999, 2001 and 2002. Light-saturated net photosynthesis and foliar nitrogen relationship were compared to determine if the stimulatory effects of elevated carbon dioxide on net photosynthesis had declined. Results at all three sample times showed no difference in either the slopes, or in the y-intercepts of the net photosynthesis-foliar nitrogen relationship when measured at common carbon dioxide concentrations. Net photosynthesis was also unaffected by growth in elevated carbon dioxide, indicating that these overstory and understory trees continued to show strong stimulation of photosynthesis by elevated carbon dioxide. 46 refs., 6 tabs., 3 figs

  15. Carbohydrate regulation of photosynthesis and respiration from branch girdling in four species of wet tropical rain forest trees.

    Science.gov (United States)

    Asao, Shinichi; Ryan, Michael G

    2015-06-01

    How trees sense source-sink carbon balance remains unclear. One potential mechanism is a feedback from non-structural carbohydrates regulating photosynthesis and removing excess as waste respiration when the balance of photosynthesis against growth and metabolic activity changes. We tested this carbohydrate regulation of photosynthesis and respiration using branch girdling in four tree species in a wet tropical rainforest in Costa Rica. Because girdling severs phloem to stop carbohydrate export while leaving xylem intact to allow photosynthesis, we expected carbohydrates to accumulate in leaves to simulate a carbon imbalance. We varied girdling intensity by removing phloem in increments of one-quarter of the circumference (zero, one--quarter, half, three-quarters, full) and surrounded a target branch with fully girdled ones to create a gradient in leaf carbohydrate content. Light saturated photosynthesis rate was measured in situ, and foliar respiration rate and leaf carbohydrate content were measured after destructive harvest at the end of the treatment. Girdling intensity created no consistent or strong responses in leaf carbohydrates. Glucose and fructose slightly increased in all species by 3.4% per one-quarter girdle, total carbon content and leaf mass per area increased only in one species by 5.4 and 5.5% per one-quarter girdle, and starch did not change. Only full girdling lowered photosynthesis in three of four species by 59-69%, but the decrease in photosynthesis was unrelated to the increase in glucose and fructose content. Girdling did not affect respiration. The results suggest that leaf carbohydrate content remains relatively constant under carbon imbalance, and any changes are unlikely to regulate photosynthesis or respiration. Because girdling also stops the export of hormones and reactive oxygen species, girdling may induce physiological changes unrelated to carbohydrate accumulation and may not be an effective method to study carbohydrate feedback

  16. 2012 Photosynthesis Gordon Research Conference and Seminar, JUL 7-13, 2012

    Energy Technology Data Exchange (ETDEWEB)

    Debus, Richard [Univ. of California, Riverside, CA (United States)

    2012-07-13

    The Gordon Research Conference on PHOTOSYNTHESIS was held at Davidson College, Davidson, North Carolina, July 8-13, 2012. The Conference was well-attended with 150 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. Of the 150 attendees, 65 voluntarily responded to a general inquiry regarding ethnicity which appears on our registration forms. Of the 65 respondents, 20% were Minorities$-$ 5% Hispanic, 15% Asian and 0% African American. Approximately 28% of the participants at the 2012 meeting were women. The Gordon Research Seminar on PHOTOSYNTHESIS held at Davidson College, Davidson, North Carolina, July 7-8, 2012.. The Conference was well-attended with 51 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. Of the 51 attendees, 22 voluntarily responded to a general inquiry regarding ethnicity which appears on our registration forms. Of the 22 respondents, 14% were Minorities $-$0% Hispanic, 14% Asian and 0% African American. Approximately 35% of the participants at the 2012 meeting were women. Focal points for talks and discussions will include: Artificial photosynthesis and solar energy conversion strategies; Engineering organisms for biofuels and hydrogen production; Electron transport, proton transport, and energy coupling; Photoprotection mechanisms; Photosynthetic reaction center structure and function, including rewiring reaction centers for artificial photosynthesis; Energy capture and light harvesting solutions, including quantum coherence; Structure of the oxygen evolving complex and the mechanism of oxygen production.

  17. Future Elementary School Teachers' Conceptual Change Concerning Photosynthesis

    Science.gov (United States)

    Ahopelto, Ilona; Mikkila-Erdmann, Mirjamaija; Anto, Erkki; Penttinen, Marjaana

    2011-01-01

    The purpose of this study was to examine conceptual change among future elementary school teachers while studying a scientific text concerning photosynthesis. Students' learning goals in relation to their learning outcomes were also examined. The participants were future elementary school teachers. The design consisted of pre- and post-tests. The…

  18. Photosynthesis versus irradiance relationships in the Atlantic sector ...

    African Journals Online (AJOL)

    The results show substantial variability in the photosynthesis–irradiance (P vs E) parameters, with phytoplankton communities at stations that were considered iron (Fe)-limited showing low maximum photosynthetic capacity (PBmax) and low quantum efficiency of photosynthesis (αB) for ρNO3, but high PBmax and αB for ...

  19. Significance of rice sheath photosynthesis: Yield determination by ...

    African Journals Online (AJOL)

    Using high-yielding hybrid rice Liangyopeijiu (LYP9), its male parent 9311 and hybrid rice Shanyou 63 (SY63) as the experimental materials, the photosynthesis of rice sheath was studied by 14C radio-autography. The results showed that rice sheath could trap sunlight and produce photosynthates, and these ...

  20. INTERACTIVE ILUSTRATION FOR PHOTOSYNTHESIS TEACHING

    Directory of Open Access Journals (Sweden)

    M.R. Pereira

    2004-05-01

    Full Text Available Computational resources became the major tool in the challenge of making high education moreeasy and motivating. Complex Biochemical pathways can now be presented in interactive and three-dimensional animations. One of the most complex (detailed and interesting metabolic pathway thatstudents must understand in biochemical courses is photosynthesis. The light-dependent reactionsare of special interest since they involve many dierent kinds of mechanisms, as light absorptionby membrane complexes, proteins movement inside membranes, reactions of water hydrolysis, andelectrons ow; making it dicult to understand by static bi-dimensional representations.The resources of animation and ActionScript programming were used to make an interactive ani-mation of photosynthesis, which at some times even simulates three-dimensionality. The animationbegins with a leaf and progressively zooms in, until we have a scheme of a tylakoyd membrane, whereeach of the dierent steps of the pathway can be clicked to reveal a more detailed scheme of it. Whereappropriate, the energy graphs are shown side by side with the reactions. The electron is representedwith a face, so it can be shown to be stressing while going up in the energy graphs. Finally, there isa simplied version of the whole pathway, to illustrate how it all goes together.The objective is to help professors on teaching the subject in regular classes, since currently allthe explanations are omitted. In a future version, texts will be added to each step so it can beself-explicative to the students, helping them even on home or on-line learning.

  1. Interaction of two photoreceptors in the regulation of bacterial photosynthesis genes.

    Science.gov (United States)

    Metz, Sebastian; Haberzettl, Kerstin; Frühwirth, Sebastian; Teich, Kristin; Hasewinkel, Christian; Klug, Gabriele

    2012-07-01

    The expression of photosynthesis genes in the facultatively photosynthetic bacterium Rhodobacter sphaeroides is controlled by the oxygen tension and by light quantity. Two photoreceptor proteins, AppA and CryB, have been identified in the past, which are involved in this regulation. AppA senses light by its N-terminal BLUF domain, its C-terminal part binds heme and is redox-responsive. Through its interaction to the transcriptional repressor PpsR the AppA photoreceptor controls expression of photosynthesis genes. The cryptochrome-like protein CryB was shown to affect regulation of photosynthesis genes, but the underlying signal chain remained unknown. Here we show that CryB interacts with the C-terminal domain of AppA and modulates the binding of AppA to the transcriptional repressor PpsR in a light-dependent manner. Consequently, binding of the transcription factor PpsR to its DNA target is affected by CryB. In agreement with this, all genes of the PpsR regulon showed altered expression levels in a CryB deletion strain after blue-light illumination. These results elucidate for the first time how a bacterial cryptochrome affects gene expression.

  2. Fiscal Year 1987 program report: Rhode Island Water Resource Research Center

    International Nuclear Information System (INIS)

    Poon, P.C.

    1988-07-01

    The 1987 program objective was to conduct studies and research of value to the New England region as well as to assist in the solution of problems in the State of Rhode Island. Current and anticipated state and regional-water problems are contamination of surface and groundwater by natural radioactivity such as radon, by chemicals from industrial and agricultural activities, septic tank and leach field, improperly managed landfills and the lack of public awareness and public participation in water-quality protection and management. It was found in the 1987 program that an epithermal neutron-activation analysis was best suitable for measuring uranium and thorium of which radon is the decayed product. Lower U and Th were found in calc-alkalic and mafic volcanic rocks while higher concentrations were found in the alkalic and peraluminous rocks. A computer model using finite-element method to simulate fluid flows through fractured porous media was developed for predicting the extent of ground-water contamination in the State

  3. The regulation of the chloroplast proton motive force plays a key role for photosynthesis in fluctuating light.

    Science.gov (United States)

    Armbruster, Ute; Correa Galvis, Viviana; Kunz, Hans-Henning; Strand, Deserah D

    2017-06-01

    Plants use sunlight as their primary energy source. During photosynthesis, absorbed light energy generates reducing power by driving electron transfer reactions. These are coupled to the transfer of protons into the thylakoid lumen, generating a proton motive force (pmf) required for ATP synthesis. Sudden alterations in light availability have to be met by regulatory mechanisms to avoid the over-accumulation of reactive intermediates and maximize energy efficiency. Here, the acidification of the lumen, as an intermediate product of photosynthesis, plays an important role by regulating photosynthesis in response to excitation energy levels. Recent findings reveal pmf regulation and the modulation of its composition as key determinants for efficient photosynthesis, plant growth, and survival in fluctuating light environments. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Effects of light intensity on the morphology and CAM photosynthesis of Vanilla planifolia Andrews

    Directory of Open Access Journals (Sweden)

    María Claudia Díez

    2017-01-01

    Full Text Available Vanilla planifolia is a neotropical orchid, whose fruits produce the natural vanilla, a fundamental ingredient for the food and cosmetic industry. Because of its importance in the world market, it is cultivated in many tropical countries and recently its cultivation has started in Colombia. This species requires shade for its development; however, the optimal of light conditions are unknown. This work evaluates the effect of different light intensities on CAM photosynthesis, physiology, morphology, and growth of this species. For this, vanilla seedlings were subjected to four treatments of relative illumination (RI (T1=8%, T2=17%, T3=31% and T4=67%. Most CO2 assimilation occurred along night in all treatments, which confirms that vanilla is a strong CAM species. Plants grown under high lighting (67% RI had almost half of the photosynthesis in treatments of intermediate lighting (17 and 31%, which is consistent with the lower nocturnal acid accumulation in that treatment. Likewise, the photochemical efficiency of photosystem II (Fv / Fm showed that in plants of the 67% RI occurred high radiation stress. On the other hand, vanilla plants reached greater length, leaf area, and total biomass when grown under intermediate radiation (17 and 31% RI. These results suggest that high radiation alters the functioning of vanilla plants, inhibiting photosynthesis and growth, and that highly shaded environments not significantly affected the CAM photosynthesis of vanilla; however, in the long-term this species showed higher photosynthesis and growth under intermediate levels of radiation

  5. Modelling basin-wide variations in Amazon forest photosynthesis

    Science.gov (United States)

    Mercado, Lina; Lloyd, Jon; Domingues, Tomas; Fyllas, Nikolaos; Patino, Sandra; Dolman, Han; Sitch, Stephen

    2010-05-01

    Given the importance of Amazon rainforest in the global carbon and hydrological cycles, there is a need to use parameterized and validated ecosystem gas exchange and vegetation models for this region in order to adequately simulate present and future carbon and water balances. Recent research has found major differences in above-ground net primary productivity (ANPP), above ground biomass and tree dynamics across Amazonia. West Amazonia is more dynamic, with younger trees, higher stem growth rates and lower biomass than central and eastern Amazon (Baker et al. 2004; Malhi et al. 2004; Phillips et al. 2004). A factor of three variation in above-ground net primary productivity has been estimated across Amazonia by Malhi et al. (2004). Different hypotheses have been proposed to explain the observed spatial variability in ANPP (Malhi et al. 2004). First, due to the proximity to the Andes, sites from western Amazonia tend to have richer soils than central and eastern Amazon and therefore soil fertility could possibly be highly related to the high wood productivity found in western sites. Second, if GPP does not vary across the Amazon basin then different patterns of carbon allocation to respiration could also explain the observed ANPP gradient. However since plant growth depends on the interaction between photosynthesis, transport of assimilates, plant respiration, water relations and mineral nutrition, variations in plant gross photosynthesis (GPP) could also explain the observed variations in ANPP. In this study we investigate whether Amazon GPP can explain variations of observed ANPP. We use a sun and shade canopy gas exchange model that has been calibrated and evaluated at five rainforest sites (Mercado et al. 2009) to simulate gross primary productivity of 50 sites across the Amazon basin during the period 1980-2001. Such simulation differs from the ones performed with global vegetation models (Cox et al. 1998; Sitch et al. 2003) where i) single plant functional

  6. Major alterations in transcript profiles between C3-C4 and C4 photosynthesis of an amphibious species Eleocharis baldwinii.

    Science.gov (United States)

    Chen, Taiyu; Zhu, Xin-Guang; Lin, Yongjun

    2014-09-01

    Engineering C4 photosynthetic metabolism into C3 crops is regarded as a major strategy to increase crop productivity, and clarification of the evolutionary processes of C4 photosynthesis can help the better use of this strategy. Here, Eleocharis baldwinii, a species in which C4 photosynthesis can be induced from a C3-C4 state under either environmental or ABA treatments, was used to identify the major transcriptional modifications during the process from C3-C4 to C4. The transcriptomic comparison suggested that in addition to the major differences in C4 core pathway, the pathways of glycolysis, citrate acid metabolism and protein synthesis were dramatically modified during the inducement of C4 photosynthetic states. Transcripts of many transporters, including not only metabolite transporters but also ion transporters, were dramatically increased in C4 photosynthetic state. Many candidate regulatory genes with unidentified functions were differentially expressed in C3-C4 and C4 photosynthetic states. Finally, it was indicated that ABA, auxin signaling and DNA methylation play critical roles in the regulation of C4 photosynthesis. In summary, by studying the different photosynthetic states of the same species, this work provides the major transcriptional differences between C3-C4 and C4 photosynthesis, and many of the transcriptional differences are potentially related to C4 development and therefore are the potential targets for reverse genetics studies.

  7. The brave new world of GEC evaluation: the experience of the Rhode Island Geriatric Education Center.

    Science.gov (United States)

    Filinson, Rachel; Clark, Phillip G; Evans, Joann; Padula, Cynthia; Willey, Cynthia

    2012-01-01

    In 2007, the Health Resources Services Administration introduced new mandates that raised the standards on program evaluation for Geriatric Education Centers. Described in this article are the primary and secondary evaluation efforts undertaken for one program within the Rhode Island Geriatric Education Center (RIGEC), the findings from these efforts, and the modifications to assessment that ensued in response to the increased accountability requirements. The evaluation focused on RIGEC's series of continuing education, day-long workshops for health and social service professionals, the completion of all seven of which leads to a Certificate in Interdisciplinary Practice in Geriatrics.

  8. Assessing parameter variability in a photosynthesis model within and between plant functional types using global Fluxnet eddy covariance data

    NARCIS (Netherlands)

    Groenendijk, M.; Dolman, A.J.; Molen, van der M.K.; Leuning, R.; Arneth, A.; Delpierre, N.; Gash, J.H.C.; Lindroth, A.; Richardson, A.D.; Verbeeck, H.; Wohlfahrt, G.

    2011-01-01

    The vegetation component in climate models has advanced since the late 1960s from a uniform prescription of surface parameters to plant functional types (PFTs). PFTs are used in global land-surface models to provide parameter values for every model grid cell. With a simple photosynthesis model we

  9. Effects of iron limitation on photosynthesis and carbohydrate metabolism in the Antarctic diatom Chaetoceros brevis (Bacillariophyceae)

    NARCIS (Netherlands)

    van Oijen, T; van Leeuwe, MA; Gieskes, WWC; de Baar, HJW

    Iron, one of the structural elements of organic components that play an essential role in photosynthesis and nitrogen assimilation of plants, is available at extremely low concentrations in large parts of the Southern Ocean's surface waters. We tested the hypothesis that photosynthesis is the

  10. Estimation of effects of photosynthesis response functions on rice yields and seasonal variation of CO2 fixation using a photosynthesis-sterility type of crop yield model

    International Nuclear Information System (INIS)

    Kaneko, D.; Moriwaki, Y.

    2008-01-01

    This study presents a crop production model improvement: the previously adopted Michaelis-Menten (MM) type photosynthesis response function (fsub(rad-MM)) was replaced with a Prioul-Chartier (PC) type function (fsub(rad-PC)). The authors' analysis reflects concerns regarding the background effect of global warming, under simultaneous conditions of high air temperature and strong solar radiation. The MM type function fsub(rad-MM) can give excessive values leading to an overestimate of photosynthesis rate (PSN) and grain yield for paddy-rice. The MM model is applicable to many plants whose (PSN) increases concomitant with increased insolation: wheat, maize, soybean, etc. For paddy rice, the PSN apparently shows a maximum PSN. This paper proves that the MM model overestimated the PSN for paddy rice for sufficient solar radiation: the PSN using the PC model yields 10% lower values. However, the unit crop production index (CPIsub(U)) is almost independent of the MM and PC models because of respective standardization of both PSN and crop production index using average PSNsub(0) and CPIsub(0). The authors improved the estimation method using a photosynthesis-and-sterility based crop situation index (CSIsub(E)) to produce a crop yield index (CYIsub(E)), which is used to estimate rice yields in place of the crop situation index (CSI); the CSI gives a percentage of rice yields compared to normal annual production. The model calculates PSN including biomass effects, low-temperature sterility, and high-temperature injury by incorporating insolation, effective air temperature, the normalized difference vegetation index (NDVI), and effects of temperature on photosynthesis. Based on routine observation data, the method enables automated crop-production monitoring in remote regions without special observations. This method can quantify grain production early to raise an alarm in Southeast Asian countries, which must confront climate fluctuation through this era of global

  11. Native and alien ichthyofauna in coastal fishery of Rhodes (eastern Mediterranean (2002-2010

    Directory of Open Access Journals (Sweden)

    Maria Corsini-Foka

    2015-11-01

    Full Text Available Rhodes Island (southeastern Aegean is located in a geographically crucial region subjected to biological invasions. Among the 108 alien species recorded, 30 are fish, all of Indo-Pacific/Red Sea origin introduced via Suez through Lessepsian migration (Corsini-Foka et al., 2015; Corsini-Foka and Kondylatos, In press; Kondylatos and Corsini-Foka, In press. In this oligotrophic area, fishery production is limited, due to the paucity of species of commercial interest and their low abundance, while adapted infrastructures for fish landing and marketing are absent. Coastal fishery has dominated during the last twenty years (ELSTAT, 2015. Within 2002-2010, the Hydrobiological Station of Rhodes conducted experimental boat seining surveys, using exclusively a professional 12m fishing boat, at 5-30 m depth, in the Gulf of Trianda (sandy mud, Posidonia meadows. The 94 carried out hauls (7-18 hauls/year, produced a total fish biomass of approximately 4400 Kg, recording 97 fish (86 native, 11 alien and 4 cephalopod species (3 native, 1 alien. Fish species ranged from 32 to 63/year, whereas aliens ranged from 5 to 8 species. Almost steadily present since 2002, were earlier colonizers such as Apogonichthyoides pharaonis, Siganus rivulatus, Siganus luridus, Stephanolepis diaspros and more recent ones as Pteragogus trispilus, Sphyraena chrysotaenia and Fistularia commersonii, while Lagocephalus sceleratus, firstly recorded in 2005, occurred regularly since 2007; the presence of Lagocephalus suezensis, Sphyraena flavicauda and Upeneus pori was scattered since their first records in 2004-2005. Alien fish commercially important are the Siganids, S. chrysotaenia and surprisingly F. commersonii. In terms of biomass per haul, alien fish ranged from 0 to 18.5 Kg, native from 1.5 to 182 Kg. Catches were dominated by Centracanthidae (Spicara spp. and Sparidae (Boops boops, sometimes by other native such as Oblada melanura, Diplodus spp., Chromis Chromis and others. The

  12. Oxygenic photosynthesis: translation to solar fuel technologies

    Directory of Open Access Journals (Sweden)

    Julian David Janna Olmos

    2014-12-01

    Full Text Available Mitigation of man-made climate change, rapid depletion of readily available fossil fuel reserves and facing the growing energy demand that faces mankind in the near future drive the rapid development of economically viable, renewable energy production technologies. It is very likely that greenhouse gas emissions will lead to the significant climate change over the next fifty years. World energy consumption has doubled over the last twenty-five years, and is expected to double again in the next quarter of the 21st century. Our biosphere is at the verge of a severe energy crisis that can no longer be overlooked. Solar radiation represents the most abundant source of clean, renewable energy that is readily available for conversion to solar fuels. Developing clean technologies that utilize practically inexhaustible solar energy that reaches our planet and convert it into the high energy density solar fuels provides an attractive solution to resolving the global energy crisis that mankind faces in the not too distant future. Nature’s oxygenic photosynthesis is the most fundamental process that has sustained life on Earth for more than 3.5 billion years through conversion of solar energy into energy of chemical bonds captured in biomass, food and fossil fuels. It is this process that has led to evolution of various forms of life as we know them today. Recent advances in imitating the natural process of photosynthesis by developing biohybrid and synthetic “artificial leaves” capable of solar energy conversion into clean fuels and other high value products, as well as advances in the mechanistic and structural aspects of the natural solar energy converters, photosystem I and photosystem II, allow to address the main challenges: how to maximize solar-to-fuel conversion efficiency, and most importantly: how to store the energy efficiently and use it without significant losses. Last but not least, the question of how to make the process of solar

  13. Short-term light and leaf photosynthetic dynamics affect estimates of daily understory photosynthesis in four tree species.

    Science.gov (United States)

    Naumburg, Elke; Ellsworth, David S

    2002-04-01

    Instantaneous measurements of photosynthesis are often implicitly or explicitly scaled to longer time frames to provide an understanding of plant performance in a given environment. For plants growing in a forest understory, results from photosynthetic light response curves in conjunction with diurnal light data are frequently extrapolated to daily photosynthesis (A(day)), ignoring dynamic photosynthetic responses to light. In this study, we evaluated the importance of two factors on A(day) estimates: dynamic physiological responses to photosynthetic photon flux density (PPFD); and time-resolution of the PPFD data used for modeling. We used a dynamic photosynthesis model to investigate how these factors interact with species-specific photosynthetic traits, forest type, and sky conditions to affect the accuracy of A(day) predictions. Increasing time-averaging of PPFD significantly increased the relative overestimation of A(day) similarly for all study species because of the nonlinear response of photosynthesis to PPFD (15% with 5-min PPFD means). Depending on the light environment characteristics and species-specific dynamic responses to PPFD, understory tree A(day) can be overestimated by 6-42% for the study species by ignoring these dynamics. Although these overestimates decrease under cloudy conditions where direct sunlight and consequently understory sunfleck radiation is reduced, they are still significant. Within a species, overestimation of A(day) as a result of ignoring dynamic responses was highly dependent on daily sunfleck PPFD and the frequency and irradiance of sunflecks. Overall, large overestimates of A(day) in understory trees may cause misleading inferences concerning species growth and competition in forest understories with sunlight. We conclude that comparisons of A(day) among co-occurring understory species in deep shade will be enhanced by consideration of sunflecks by using high-resolution PPFD data and understanding the physiological

  14. Ecosystem Phenology from Eddy-covariance Measurements: Spring Photosynthesis in a Cool Temperate Bog

    Science.gov (United States)

    Lafleur, P.; Moore, T. R.; Poon, D.; Seaquist, J.

    2005-12-01

    The onset and increase of spring photosynthetic flux of carbon dioxide is an important attribute of the carbon budget of northern ecosystems and we used eddy-covariance measurements from March to May over 5 years at the Mer Bleue ombrotrophic bog to establish the important controls. The onset of ecosystem photosynthesis (day-of-year from 86 to 101) was associated with the disappearance on the snow cover and there is evidence that photosynthesis can continue after a thin new snowfall. The growth of photosynthesis during the spring period was partially associated with light (daily photosynthetically active radiation) but primarily with temperature, with the strongest correlation being observed with peat temperature at a depth of 5 and 10 cm, except in one year in which there was a long snow cover. The vegetation comprises mosses, which are able to photosynthesize very early, evergreen shrubs, which appear dependent on soil warming, and deciduous shrubs, which leaf-out only in late spring. We observed changes in shrub leaf colour from brown to green and concomitant increases in foliar nitrogen and chlorophyll concentrations during the spring in this "evergreen" system. We analyzed MODIS images for periods of overlap of tower and satellite data and found a generally strong correlation, though the infrequent satellite measurements were unable to pick out the onset and timing of rapid growth of photosynthesis in this ecosystem.

  15. Photosynthesis by isolated chloroplasts. IV. General concept and comparison of three photochemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Arnon, D I; Allen, M B; Whatley, F R

    1956-01-01

    Procedures are described for the preparation of chloroplasts capable of carrying out three photochemical reactions, each representing an increasingly complex phase of photosynthesis: photolysis of water (Hill reaction), esterification of inorganic phosphate into adenosine triphosphate (photosynthetic phosphorylation) and the reduction of carbon dioxide to the level of carbohydrates with a simultaneous evolution of oxygen. The three photochemical reactions were separable by variations in the technique for preparation of chloroplasts and by differential inhibition by several reagents. Inhibition of a more complex phase of photosynthesis does not affect the simpler one which precedes it and, conversely, the inhibition of a simpler phase of photosynthesis is paralleled by an inhibition of the more complex phase which follows. Reversible inhibition of CO/sub 2/ fixation and photosynthetic phosphorylation, but not of photolysis, by sulfhydryl group inhibitors suggests that sulfhydryl compounds (enzymes, cofactors, or both) are involved in phosphorylation and CO/sub 2/ fixation, but not in the primary conversion of light into chemical energy as measured by the Hill reaction. Evidence is presented in support of the conclusion that the synthesis of ATP by green cells occurs at two distinct sites: anaerobically in chloroplasts by photosynthetic phosphorylation, and acrobically in smaller cytoplasmic particles, presumably mitochondria, by oxidative phosphorylation independent of light. A general scheme of photosynthesis by chloroplasts, consistent with these findings, is presented. 44 references, 8 figures, 4 tables.

  16. Are changes in sulfate assimilation pathway needed for evolution of C4 photosynthesis?

    Directory of Open Access Journals (Sweden)

    Silke Christine Weckopp

    2015-01-01

    Full Text Available C4 photosynthesis characteristically features a cell-specific localization of enzymes involved in CO2 assimilation in bundle sheath cells or mesophyll cells. Interestingly, enzymes of sulfur assimilation are also specifically present in bundle sheath cells of maize and many other C4 species. This localization, however, could not be confirmed in C4 species of the genus Flaveria. It was, therefore, concluded that the bundle sheath localization of sulfate assimilation occurs only in C4 monocots. However, recently the sulfate assimilation pathway was found coordinately enriched in bundle sheath cells of Arabidopsis, opening new questions about the significance of such cell-specific localization of the pathway. In addition, next generation sequencing revealed expression gradients of many genes from C3 to C4 species and mathematical modelling proposed a sequence of adaptations during the evolutionary path from C3 to C4. Indeed, such gradient, with higher expression of genes for sulfate reduction in C4 species, has been observed within the genus Flaveria. These new tools provide the basis for reexamining the intriguing question of compartmentalization of sulfur assimilation. Therefore, this review summarizes the findings on spatial separation of sulfur assimilation in C4 plants and Arabidopsis, assesses the information on sulfur assimilation provided by the recent transcriptomics data and discusses their possible impact on understanding this interesting feature of plant sulfur metabolism to find out whether changes in sulfate assimilation are part of a general evolutionary trajectory towards C4 photosynthesis.

  17. 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.

  18. Complete chloroplast genome sequence of green foxtail (Setaria viridis), a promising model system for C4 photosynthesis.

    Science.gov (United States)

    Wang, Shuo; Gao, Li-Zhi

    2016-09-01

    The complete chloroplast genome of green foxtail (Setaria viridis), a promising model system for C4 photosynthesis, is first reported in this study. The genome harbors a large single copy (LSC) region of 81 016 bp and a small single copy (SSC) region of 12 456  bp separated by a pair of inverted repeat (IRa and IRb) regions of 22 315 bp. GC content is 38.92%. The proportion of coding sequence is 57.97%, comprising of 111 (19 duplicated in IR regions) unique genes, 71 of which are protein-coding genes, four are rRNA genes, and 36 are tRNA genes. Phylogenetic analysis indicated that S. viridis was clustered with its cultivated species S. italica in the tribe Paniceae of the family Poaceae. This newly determined chloroplast genome will provide valuable genetic resources to assist future studies on C4 photosynthesis in grasses.

  19. The potential feasibility of chlorinic photosynthesis on exoplanets.

    Science.gov (United States)

    Haas, Johnson R

    2010-11-01

    The modern search for life-bearing exoplanets emphasizes the potential detection of O(2) and O(3) absorption spectra in exoplanetary atmospheres as ideal signatures of biology. However, oxygenic photosynthesis may not arise ubiquitously in exoplanetary biospheres. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This paper defines chlorinic photosynthesis (CPS) as biologically mediated photolytic oxidation of aqueous Cl(-) to form halocarbon or dihalogen products, coupled with CO(2) assimilation. This hypothetical metabolism appears to be feasible energetically, physically, and geochemically, and could potentially develop under conditions that approximate the terrestrial Archean. It is hypothesized that an exoplanetary biosphere in which chlorinic photosynthesis dominates primary production would tend to evolve a strongly oxidizing, halogen-enriched atmosphere over geologic time. It is recommended that astronomical observations of exoplanetary outgoing thermal emission spectra consider signs of halogenated chemical species as likely indicators of the presence of a chlorinic biosphere. Planets that favor the evolution of CPS would probably receive equivalent or greater surface UV flux than is produced by the Sun, which would promote stronger abiotic UV photolysis of aqueous halides than occurred during Earth's Archean era and impose stronger evolutionary selection pressures on endemic life to accommodate and utilize halogenated compounds. Ocean-bearing planets of stars with metallicities equivalent to, or greater than, the Sun should especially favor the evolution of chlorinic biospheres because of the higher relative seawater abundances of Cl, Br, and I such planets would tend to host. Directed searches for chlorinic biospheres should probably focus on G0-G2, F, and A spectral class stars that have bulk metallicities of +0.0 Dex or greater.

  20. Effects of light and temperature on duckweed photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Wedge, R M; Burris, J E

    1982-06-01

    Rates of photosynthesis of Lemna minor L. and Spirodela punctata, two aquatic angiosperms, were measured at different temperatures and light intensities. Photosynthesis was measured both as oxygen evolution and /sup 14/CO/sub 2/ fixation. At temperatures ranging from 15 to 35/sup 0/C, light saturation of photosynthetic O/sub 2/ evolution of Lemna occured from 300-600 ..mu..E m/sup -2/ s/sup -1/, while in Spirodela photosynthetic O/sub 2/ evolution was light saturated at 5600-1200 ..mu..E m/sup -2/ s/sup -1/. Photosynthetic O/sub 2/ evolution of both species was photoinhibited at light intensities greater than 1200 ..mu..E m/sup -2/ s/sup -1/. The optimal temperature for Lemna photosynthetic O/sub 2/ evolution was 30/sup 0/C, while the optimal temperatures for /sup 14/CO/sub 2/ fixation were from 20 to 30/sup 0/C. For Spirodela maximum photosynthetic O/sub 2/, evolution occurred at 35/sup 0/C, while maximum /sup 14/CO/sub 2/ fixation was at 30/sup 0/C.

  1. Biocatalytic photosynthesis with water as an electron donor.

    Science.gov (United States)

    Ryu, Jungki; Nam, Dong Heon; Lee, Sahng Ha; Park, Chan Beum

    2014-09-15

    Efficient harvesting of unlimited solar energy and its conversion into valuable chemicals is one of the ultimate goals of scientists. With the ever-increasing concerns about sustainable growth and environmental issues, numerous efforts have been made to develop artificial photosynthetic process for the production of fuels and fine chemicals, thus mimicking natural photosynthesis. Despite the research progress made over the decades, the technology is still in its infancy because of the difficulties in kinetic coupling of whole photocatalytic cycles. Herein, we report a new type of artificial photosynthesis system that can avoid such problems by integrally coupling biocatalytic redox reactions with photocatalytic water splitting. We found that photocatalytic water splitting can be efficiently coupled with biocatalytic redox reactions by using tetracobalt polyoxometalate and Rh-based organometallic compound as hole and electron scavengers, respectively, for photoexcited [Ru(bpy)3](2+). Based on these results, we could successfully photosynthesize a model chiral compound (L-glutamate) using a model redox enzyme (glutamate dehydrogenase) upon in situ photoregeneration of cofactors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Relative Sensitivity of Photosynthesis and Respiration to Freeze-Thaw Stress in Herbaceous Species 1

    Science.gov (United States)

    Steffen, Kenneth L.; Arora, Rajeev; Palta, Jiwan P.

    1989-01-01

    The relative effect of a freeze-thaw cycle on photosynthesis, respiration, and ion leakage of potato leaf tissue was examined in two potato species, Solanum acaule Bitt. and Solanum commersonii Dun. Photosynthesis was found to be much more sensitive to freezing stress than was respiration, and demonstrated more than a 60% inhibition before any impairment of respiratory function was observed. Photosynthesis showed a slight to moderate inhibition when only 5 to 10% of the total electrolytes had leaked from the tissue (reversible injury). This was in contrast to respiration which showed no impairment until temperatures at which about 50% ion leakage (irreversible injury) had occurred. The influence of freeze-thaw protocol was further examined in S. acaule and S. commersonii, in order to explore discrepancies in the literature as to the relative sensitivities of photosynthesis and respiration. As bath cooling rates increased from 1°C/hour to about 3 or 6°C/hour, there was a dramatic increase in the level of damage to all measured cellular functions. The initiation of ice formation in deeply supercooled tissue caused even greater damage. As the cooling rates used in stress treatments increased, the differential sensitivity between photosynthesis and respiration nearly disappeared. Examination of agriculturally relevant, climatological data from an 11 year period confirmed that air cooling rates in the freezing range do not exceed 2°C/hour. It was demonstrated, in the studies presented here, that simply increasing the actual cooling rate from 1.0 to 2.9°C/hour, in frozen tissue from paired leaflet halves, meant the difference between cell survival and cell death. Images Figure 4 Figure 5 PMID:16666712

  3. Photosynthesis and Ribulose 1,5-Bisphosphate Concentrations in Intact Leaves of Xanthium strumarium L.

    Science.gov (United States)

    Mott, K A; Jensen, R G; O'leary, J W; Berry, J A

    1984-12-01

    The interacting effects of the rate of ribulose 1,5-bisphosphate (RuBP) regeneration and the rate of RuBP utilization as influenced by the amount and activation of RuBP carboxylase on photosynthesis and RuBP concentrations were resolved in experiments which examined the kinetics of the response of photosynthesis and RuBP concentrations after step changes from a rate-saturating to a rate-limiting light intensity in Xanthium strumarium. Because RuBP carboxylase requires several minutes to deactivate in vivo, it was possible to observe the effect of reducing the rate of RuBP regeneration on the RuBP concentration at constant enzyme activation state by sampling very soon after reducing the light intensity. Samples taken over longer time periods showed the effect of changes in enzyme activation at constant RuBP regeneration rate on RuBP concentration and photosynthetic rate. Within 15 s of lowering the light intensity from 1500 to 600 microEinsteins per square meter per second the RuBP concentration in the leaves dropped below the enzyme active site concentration, indicating that RuBP regeneration rate was limiting for photosynthesis. After longer intervals of time, the RuBP concentration in the leaf increased as the RuBP carboxylase assumed a new steady state activation level. No change in the rate of photosynthesis was observed during the interval that RuBP concentration increased. It is concluded that the rate of photosynthesis at the lower light intensity was limited by the rate of RuBP regeneration and that parallel changes in the activation of RuBP carboxylase occurred such that concentrations of RuBP at steady state were not altered by changes in light intensity.

  4. Artificial photosynthesis: from basic biology to industrial application

    National Research Council Canada - National Science Library

    Collings, Anthony F; Critchley, Christa

    2005-01-01

    ... some of the same outcomes at rates and scales that far exceed those found in nature. In this field the ubiquitous process is photosynthesis - an ancient process inherent to almost all plants and many prokaryotes on the planet that ultimately enabled the development of earth's animal kingdom. From a practical perspective, the natural process of photosynth...

  5. 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.

  6. A two-dimensional microscale model of gas exchange during photosynthesis in maize (Zea mays L.) leaves.

    Science.gov (United States)

    Retta, Moges; Ho, Quang Tri; Yin, Xinyou; Verboven, Pieter; Berghuijs, Herman N C; Struik, Paul C; Nicolaï, Bart M

    2016-05-01

    CO2 exchange in leaves of maize (Zea mays L.) was examined using a microscale model of combined gas diffusion and C4 photosynthesis kinetics at the leaf tissue level. Based on a generalized scheme of photosynthesis in NADP-malic enzyme type C4 plants, the model accounted for CO2 diffusion in a leaf tissue, CO2 hydration and assimilation in mesophyll cells, CO2 release from decarboxylation of C4 acids, CO2 fixation in bundle sheath cells and CO2 retro-diffusion from bundle sheath cells. The transport equations were solved over a realistic 2-D geometry of the Kranz anatomy obtained from light microscopy images. The predicted responses of photosynthesis rate to changes in ambient CO2 and irradiance compared well with those obtained from gas exchange measurements. A sensitivity analysis showed that the CO2 permeability of the mesophyll-bundle sheath and airspace-mesophyll interfaces strongly affected the rate of photosynthesis and bundle sheath conductance. Carbonic anhydrase influenced the rate of photosynthesis, especially at low intercellular CO2 levels. In addition, the suberin layer at the exposed surface of the bundle sheath cells was found beneficial in reducing the retro-diffusion. The model may serve as a tool to investigate CO2 diffusion further in relation to the Kranz anatomy in C4 plants. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. Physiological basis of genetic variation in leaf photosynthesis among rice (Oryza sativa L.) introgression lines under drought and well-watered conditions

    Science.gov (United States)

    Yin, Xinyou

    2012-01-01

    To understand the physiological basis of genetic variation and resulting quantitative trait loci (QTLs) for photosynthesis in a rice (Oryza sativa L.) introgression line population, 13 lines were studied under drought and well-watered conditions, at flowering and grain filling. Simultaneous gas exchange and chlorophyll fluorescence measurements were conducted at various levels of incident irradiance and ambient CO2 to estimate parameters of a model that dissects photosynthesis into stomatal conductance (g s), mesophyll conductance (g m), electron transport capacity (J max), and Rubisco carboxylation capacity (V cmax). Significant genetic variation in these parameters was found, although drought and leaf age accounted for larger proportions of the total variation. Genetic variation in light-saturated photosynthesis and transpiration efficiency (TE) were mainly associated with variation in g s and g m. One previously mapped major QTL of photosynthesis was associated with variation in g s and g m, but also in J max and V cmax at flowering. Thus, g s and g m, which were demonstrated in the literature to be responsible for environmental variation in photosynthesis, were found also to be associated with genetic variation in photosynthesis. Furthermore, relationships between these parameters and leaf nitrogen or dry matter per unit area, which were previously found across environmental treatments, were shown to be valid for variation across genotypes. Finally, the extent to which photosynthesis rate and TE can be improved was evaluated. Virtual ideotypes were estimated to have 17.0% higher photosynthesis and 25.1% higher TE compared with the best genotype investigated. This analysis using introgression lines highlights possibilities of improving both photosynthesis and TE within the same genetic background. PMID:22888131

  8. Effects of enhances ultra violet irradiation on photosynthesis in ...

    African Journals Online (AJOL)

    Effects of enhances ultra violet irradiation on photosynthesis in anabaena variabilis and phormidium uncinatum. VA Donkor. Abstract. No Abstract. Journal of the Ghana Association Vol. 2 (3) 1999: pp.16-23. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  9. Photosynthesis-dependent isoprene emission from leaf to planet in a global carbon-chemistry-climate model

    OpenAIRE

    Unger, N.; Harper, K.; Zheng, Y.; Kiang, N. Y.; Aleinov, I.; Arneth, A.; Schurgers, G.; Amelynyck, C.; Goldstein, A.; Guenther, A.; Heinesch, B.; Hewitt, C. N.; Karl, T.; Laffineur, Q.; Langford, B.

    2013-01-01

    We describe the implementation of a biochemical model of isoprene emission that depends on the electron requirement for isoprene synthesis into the Farquhar–Ball–Berry leaf model of photosynthesis and stomatal conductance that is embedded within a global chemistry-climate simulation framework. The isoprene production is calculated as a function of electron transport-limited photosynthesis, intercellular and atmospheric carbon dioxide concentration, and canopy temperature. Th...

  10. A two-dimensional microscale model of gas exchange during photosynthesis in maize (Zea mays L.) leaves

    NARCIS (Netherlands)

    Retta, Moges; Ho, Quang Tri; Yin, Xinyou; Verboven, Pieter; Berghuijs, Herman N.C.; Struik, Paul C.; Nicolaï, Bart M.

    2016-01-01

    CO2 exchange in leaves of maize (Zea mays L.) was examined using a microscale model of combined gas diffusion and C4 photosynthesis kinetics at the leaf tissue level. Based on a generalized scheme of photosynthesis in NADP-malic enzyme type C4 plants, the model

  11. Crown structure, radiation absorption, photosynthesis and transpiration

    OpenAIRE

    Wang, Yingping

    1988-01-01

    A complex simulation model, MAESTRO, has been developed and validated against field measurements in plantation in both Scotland and Australia. It has been shown that MAESTRO can reasonably predict the daily course of PAR (photosynetically active radiation) transmittance at points below the canopies of radiata pine and Sitka spruce plantations. 1. Four structural properties of the Sitka spruce tree crown have been identified and evaluation in relation to PAR absorption, photosynthesis and ...

  12. In situ autumn ozone fumigation of mature Norway spruce - Effects on net photosynthesis

    DEFF Research Database (Denmark)

    Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2002-01-01

    concentration. The experiment was conducted during 70 days during the autumn. Our system could not detect any ozone effects on dark respiration, but eventually effects on dark respiration could be masked in signal noise. An inhibition of daily net photosynthesis in ozone treated shoots was apparent......, and it is was found that a mean increase in ozone concentration of 10 nl l(-1) reduced net photosynthesis with 7.4 %. This effect should be related to a pre-exposure during the season of AOT40 12.5 mul l(-1) h....

  13. UV-B sensitivity of plant photosynthesis as influenced by visible irradiation

    International Nuclear Information System (INIS)

    Caldwell, M.M.; Warner, C.W.

    1982-01-01

    Experiments were made to separate the effects of preconditioning and concomitant visible irradiation and to investigate this with respect to both light-limited and light-saturated photosynthesis. (orig./AJ)

  14. Pectin Methylesterification Impacts the Relationship between Photosynthesis and Plant Growth1[OPEN

    Science.gov (United States)

    Kim, Sang-Jin; Renna, Luciana; Brandizzi, Federica

    2016-01-01

    Photosynthesis occurs in mesophyll cells of specialized organs such as leaves. The rigid cell wall encapsulating photosynthetic cells controls the expansion and distribution of cells within photosynthetic tissues. The relationship between photosynthesis and plant growth is affected by leaf area. However, the underlying genetic mechanisms affecting carbon partitioning to different aspects of leaf growth are not known. To fill this gap, we analyzed Arabidopsis plants with altered levels of pectin methylesterification, which is known to modulate cell wall plasticity and plant growth. Pectin methylesterification levels were varied through manipulation of cotton Golgi-related (CGR) 2 or 3 genes encoding two functionally redundant pectin methyltransferases. Increased levels of methylesterification in a line over-expressing CGR2 (CGR2OX) resulted in highly expanded leaves with enhanced intercellular air spaces; reduced methylesterification in a mutant lacking both CGR-genes 2 and 3 (cgr2/3) resulted in thin but dense leaf mesophyll that limited CO2 diffusion to chloroplasts. Leaf, root, and plant dry weight were enhanced in CGR2OX but decreased in cgr2/3. Differences in growth between wild type and the CGR-mutants can be explained by carbon partitioning but not by variations in area-based photosynthesis. Therefore, photosynthesis drives growth through alterations in carbon partitioning to new leaf area growth and leaf mass per unit leaf area; however, CGR-mediated pectin methylesterification acts as a primary factor in this relationship through modulation of the expansion and positioning of the cells in leaves, which in turn drive carbon partitioning by generating dynamic carbon demands in leaf area growth and leaf mass per unit leaf area. PMID:27208234

  15. Changes in photosynthesis and activities of enzymes involved in ...

    African Journals Online (AJOL)

    AJL

    2012-04-26

    Apr 26, 2012 ... oxygen and carbohydrates. In photosynthesis, a series of redox reactions occur in the electron transport system present in the chloroplast thylakoid membranes. Oxi- dation of water is catalyzed by photosystem II (PSII), a multi-subunit pigment protein complex located in the thylakoid membrane (Hillier and ...

  16. Effects of proline on photosynthesis, root reactive oxygen species ...

    African Journals Online (AJOL)

    use

    2011-12-14

    Dec 14, 2011 ... Hoagland's nutrient solution (pH 6.3 to 6.5, EC 2.0 to 2.2 dS m-1). The nutrient .... photosynthesis system (LI-6400, LI-COR, Lincoln, NE, USA). The ..... Duan JJ, Li J, Guo SR, Kang YY (2008). ... Foster JG, Hess JL (1980).

  17. From systems biology to photosynthesis and whole-plant physiology: a conceptual model for integrating multi-scale networks.

    Science.gov (United States)

    Weston, David J; Hanson, Paul J; Norby, Richard J; Tuskan, Gerald A; Wullschleger, Stan D

    2012-02-01

    Network analysis is now a common statistical tool for molecular biologists. Network algorithms are readily used to model gene, protein and metabolic correlations providing insight into pathways driving biological phenomenon. One output from such an analysis is a candidate gene list that can be responsible, in part, for the biological process of interest. The question remains, however, as to whether molecular network analysis can be used to inform process models at higher levels of biological organization. In our previous work, transcriptional networks derived from three plant species were constructed, interrogated for orthology and then correlated with photosynthetic inhibition at elevated temperature. One unique aspect of that study was the link from co-expression networks to net photosynthesis. In this addendum, we propose a conceptual model where traditional network analysis can be linked to whole-plant models thereby informing predictions on key processes such as photosynthesis, nutrient uptake and assimilation, and C partitioning.

  18. Limited effect of ozone reductions on the 20-year photosynthesis trend at Harvard forest.

    Science.gov (United States)

    Yue, Xu; Keenan, Trevor F; Munger, William; Unger, Nadine

    2016-11-01

    Ozone (O 3 ) damage to leaves can reduce plant photosynthesis, which suggests that declines in ambient O 3 concentrations ([O 3 ]) in the United States may have helped increase gross primary production (GPP) in recent decades. Here, we assess the effect of long-term changes in ambient [O 3 ] using 20 years of observations at Harvard forest. Using artificial neural networks, we found that the effect of the inclusion of [O 3 ] as a predictor was slight, and independent of O 3 concentrations, which suggests limited high-frequency O 3 inhibition of GPP at this site. Simulations with a terrestrial biosphere model, however, suggest an average long-term O 3 inhibition of 10.4% for 1992-2011. A decline of [O 3 ] over the measurement period resulted in moderate predicted GPP trends of 0.02-0.04 μmol C m -2  s -1  yr -1 , which is negligible relative to the total observed GPP trend of 0.41 μmol C m -2  s -1  yr -1 . A similar conclusion is achieved with the widely used AOT40 metric. Combined, our results suggest that ozone reductions at Harvard forest are unlikely to have had a large impact on the photosynthesis trend over the past 20 years. Such limited effects are mainly related to the slow responses of photosynthesis to changes in [O 3 ]. Furthermore, we estimate that 40% of photosynthesis happens in the shade, where stomatal conductance and thus [O 3 ] deposition is lower than for sunlit leaves. This portion of GPP remains unaffected by [O 3 ], thus helping to buffer the changes of total photosynthesis due to varied [O 3 ]. Our analyses suggest that current ozone reductions, although significant, cannot substantially alleviate the damages to forest ecosystems. © 2016 John Wiley & Sons Ltd.

  19. Toxic effects of chlorinated organic compounds and potassium dichromate on growth rate and photosynthesis of marine phytoplankton

    DEFF Research Database (Denmark)

    Kusk, Kresten Ole; Nyholm, Niels

    1992-01-01

    The toxic effects of potassium dichromate (K2Cr2O7), 3,4-dichloroaniline (DCA) and 2,4-dichlorophenol (DCP) on the photosynthesis of natural marine phytoplankton and five species of marine microalgae were investigated. Effect concentrations corresponding to a 50 % depression of photosynthesis (6h...

  20. Changes in leaf area, nitrogen content and canopy photosynthesis in soybean exposed to an ozone concentration gradient

    Science.gov (United States)

    Influences of ozone (O3) on light-saturated rates of photosynthesis in crop leaves have been well documented. To increase our understanding of O3 effects on individual- or stand level productivity, a mechanistic understanding of factors determining canopy photosynthesis is necessary. We used a canop...

  1. Effects of ultraviolet light on photosynthesis and pigments of Antarctic marine phytoplankton

    International Nuclear Information System (INIS)

    Stephens, F.C.

    1989-01-01

    This field study was conducted at Palmer Station, Anvers Island, Antarctica, during November-December, 1987. The main objectives were to quantify the effects on photosynthetic rates and pigmentation of short-term and long-term exposures of Antarctic phytoplankton to different levels of UV radiation. Phytoplankton and ice algae were exposed to four levels of UV radiation in outdoor incubation chambers: near ambient UV; UV enhanced by approximately 5% over ambient levels; reduced UV-B; and essentially no UV. Results of 4-hour studies showed that rates of phytoplankton photosynthesis were generally inversely related to UV exposure. Higher photosynthetic rates were maintained over a greater range of irradiance levels when UV was removed in photosynthesis-irradiance studies. Photosynthetic pigments did not change with variations in either visible or UV light. After adaptation for 24 hours, photosynthetic rate measured under conditions of essentially no UV was approximately twice that measured under near ambient UV conditions. Results of photosynthesis-irradiance experiments indicate that photosynthetic efficiencies (α), maximum photosynthetic rates (P max ) and the index of inhibition (I b ) were inversely related to UV levels, probably due at least in part to the loss of chlorophyll a

  2. Inorganic Carbon Source for Photosynthesis in the Seagrass Thalassia hemprichii (Ehrenb.) Aschers.

    Science.gov (United States)

    Abel, K M

    1984-11-01

    Photosynthetic carbon uptake of the tropical seagrass Thalassia hemprichii (Ehrenb.) Aschers was studied by several methods. Photosynthesis in buffered seawater in media in the range of pH 6 to pH 9 showed an exponentially increasing rate with decreasing pH, thus indicating that free CO(2) was a photosynthetic substrate. However, these experiments were unable to determine whether photosynthesis at alkaline pH also contained some component due to HCO(3) (-) uptake. This aspect was further investigated by studying photosynthetic rates in a number of media of varying pH (7.8-8.61) and total inorganic carbon (0.75-13.17 millimolar). In these media, photosynthetic rate was correlated with free CO(2) concentration and was independent of the HCO(3) (-) concentration in the medium. Short time-course experiments were conducted during equilibration of free CO(2) and HCO(3) (-) after injection of (14)C labeled solution at acid or alkaline pH. High initial photosynthetic rates were observed when acidic solutions (largely free CO(2)) were used but not with alkaline solutions. The concentration of free CO(2) was found to be a limiting factor for photosynthesis in this plant.

  3. Regressive Evolution of Photosynthesis in the Roseobacter Clade

    Czech Academy of Sciences Publication Activity Database

    Koblížek, Michal; Zeng, Yonghui; Horák, A.; Oborník, Miroslav

    2013-01-01

    Roč. 66, č. 2013 (2013), s. 385-405 ISSN 0065-2296 R&D Projects: GA ČR GAP501/10/0221; GA ČR GBP501/12/G055; GA MŠk ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : roseobacter clade * photosynthesis * marine microbial communities Subject RIV: EE - Microbiology, Virology Impact factor: 1.740, year: 2013

  4. The Center for the Study of Early Events in Photosynthesis. Final report, September 1, 1988--August 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Orr, L.A.

    1994-12-31

    The ASU Center for the Study of Early Events in Photosynthesis was established in 1988 with funding through a five-year grant from the USDA/DOE/NSF Plant Science Center program and a grant from the NSF Biological Facilities program. Its scientific objective is to elucidate the basic principles that govern photosynthetic energy collection and storage. Understanding these principles is vital to mankind, as photosynthesis provides most of our food, fiber and energy needs. The Center attempts to fulfill this objective through research of the highest standard, coupled inextricably with quality education at the undergraduate, graduate and postdoctoral levels. These goals are met via a network of collaborative, interdisciplinary research groups comprising 100 personnel within the Department of Chemistry and Biochemistry, the Department of Botany, and the Department of Physics and Astronomy. The work of these research groups is facilitated by the Center through a variety of important infrastructural functions.

  5. Light dependence of carboxylation capacity for C3 photosynthesis models

    Science.gov (United States)

    Photosynthesis at high light is often modelled by assuming limitation by the maximum capacity of Rubisco carboxylation at low carbon dioxide concentrations, by electron transport capacity at higher concentrations, and sometimes by triose-phosphate utilization rate at the highest concentrations. Pho...

  6. An Initial evaluation of law enforcement overdose training in Rhode Island.

    Science.gov (United States)

    Saucier, Cory D; Zaller, Nickolas; Macmadu, Alexandria; Green, Traci C

    2016-05-01

    To assess initial change in knowledge, self-efficacy, and anticipated behaviors among Rhode Island law enforcement officers on drug overdose response and prevention. Law enforcement officers (N=316) voluntarily completed a pre-post evaluation immediately before and after taking part in overdose prevention and response trainings. Assessment items included measures of knowledge (Brief Overdose Recognition and Response Assessment (BORRA)), self-efficacy, attitudes toward drugs and overdose prevention, awareness of the Good Samaritan Law, and open-ended items pertaining to overdose knowledge and response behaviors. Non-parametric tests measured within-group and between-group differences. Wilcoxon Signed Rank tests and Kruskal-Wallis tests evaluated changes in BORRA scores and self-efficacy items. McNemar's tests assessed changes regarding the Good Samaritan law and open-ended items. Wilcoxon Signed Rank tests measured post-training change in attitudes. Law enforcement officers demonstrated statistically significant improvements in self-efficacy (identifying signs of opioid overdose, naloxone indication, counseling witnesses in overdose prevention, and referring witnesses for more information), overdose identification knowledge (BORRA mean increased from 7.00 to 10.39), naloxone administration knowledge (BORRA mean increased from 10.15 to 12.59), Good Samaritan Law awareness (17.9% increase after training), and anticipated behaviors in response to future observed overdose (65.7% changed from passive to active response post training). Harm reduction programs can provide law enforcement officers with the knowledge and skills necessary to intervene and reduce overdose mortality. Given the statistically significant improvements in self-efficacy, attitudinal changes, and Good Samaritan law awareness, law enforcement officers are more prepared to actively interact with drug users during a drug-involved emergency. Copyright © 2016. Published by Elsevier Ireland Ltd.

  7. Pea p68, a DEAD-box helicase, provides salinity stress tolerance in transgenic tobacco by reducing oxidative stress and improving photosynthesis machinery.

    Science.gov (United States)

    Tuteja, Narendra; Banu, Mst Sufara Akhter; Huda, Kazi Md Kamrul; Gill, Sarvajeet Singh; Jain, Parul; Pham, Xuan Hoi; Tuteja, Renu

    2014-01-01

    The DEAD-box helicases are required mostly in all aspects of RNA and DNA metabolism and they play a significant role in various abiotic stresses, including salinity. The p68 is an important member of the DEAD-box proteins family and, in animal system, it is involved in RNA metabolism including pre-RNA processing and splicing. In plant system, it has not been well characterized. Here we report the cloning and characterization of p68 from pea (Pisum sativum) and its novel function in salinity stress tolerance in plant. The pea p68 protein self-interacts and is localized in the cytosol as well as the surrounding of cell nucleus. The transcript of pea p68 is upregulated in response to high salinity stress in pea. Overexpression of p68 driven by constitutive cauliflower mosaic virus-35S promoter in tobacco transgenic plants confers enhanced tolerances to salinity stress by improving the growth, photosynthesis and antioxidant machinery. Under stress treatment, pea p68 overexpressing tobacco accumulated higher K+ and lower Na+ level than the wild-type plants. Reactive oxygen species (ROS) accumulation was remarkably regulated by the overexpression of pea p68 under salinity stress conditions, as shown from TBARS content, electrolyte leakage, hydrogen peroxide accumulation and 8-OHdG content and antioxidant enzyme activities. To the best of our knowledge this is the first direct report, which provides the novel function of pea p68 helicase in salinity stress tolerance. The results suggest that p68 can also be exploited for engineering abiotic stress tolerance in crop plants of economic importance.

  8. Enhanced limonene production in cyanobacteria reveals photosynthesis limitations.

    Science.gov (United States)

    Wang, Xin; Liu, Wei; Xin, Changpeng; Zheng, Yi; Cheng, Yanbing; Sun, Su; Li, Runze; Zhu, Xin-Guang; Dai, Susie Y; Rentzepis, Peter M; Yuan, Joshua S

    2016-12-13

    Terpenes are the major secondary metabolites produced by plants, and have diverse industrial applications as pharmaceuticals, fragrance, solvents, and biofuels. Cyanobacteria are equipped with efficient carbon fixation mechanism, and are ideal cell factories to produce various fuel and chemical products. Past efforts to produce terpenes in photosynthetic organisms have gained only limited success. Here we engineered the cyanobacterium Synechococcus elongatus PCC 7942 to efficiently produce limonene through modeling guided study. Computational modeling of limonene flux in response to photosynthetic output has revealed the downstream terpene synthase as a key metabolic flux-controlling node in the MEP (2-C-methyl-d-erythritol 4-phosphate) pathway-derived terpene biosynthesis. By enhancing the downstream limonene carbon sink, we achieved over 100-fold increase in limonene productivity, in contrast to the marginal increase achieved through stepwise metabolic engineering. The establishment of a strong limonene flux revealed potential synergy between photosynthate output and terpene biosynthesis, leading to enhanced carbon flux into the MEP pathway. Moreover, we show that enhanced limonene flux would lead to NADPH accumulation, and slow down photosynthesis electron flow. Fine-tuning ATP/NADPH toward terpene biosynthesis could be a key parameter to adapt photosynthesis to support biofuel/bioproduct production in cyanobacteria.

  9. Phytoremediation capacity of poplar (Populus spp. and willow (Salix spp. clonesin relation to photosynthesis

    Directory of Open Access Journals (Sweden)

    Pajević Slobodanka

    2009-01-01

    Full Text Available Good photosynthetic features and a favorable water regimes of woody plants improve their survival and remediation potential under unfavorable ecological conditions. Accordingly, we here present results of testing plant tolerance of Pb, Cd, Ni, and diesel fuel based on gas exchange parameters and WUE of four poplar and two willow clones grown in a greenhouse on soil culture. Photosynthesis and transpiration of plants grown on soils with individually applied heavy metals decreased significantly, but this was less obvious in the case of Cd treatment. A heavy metal mixture in the soil induced significant reduction in photosynthesis (by more than 50%. Diesel fuel as the only pollutant in soil caused very strong and significant inhibition of photosynthesis and transpiration of willow clones. The results indicate genotypic specificity of all investigated physiological parameters and mark poplar clones as very useful in phytoextraction technology for the bio-cleaning of chemically polluted soils.

  10. An Experimental Comparison of Two Methods on Photosynthesis Driving Soil Respiration: Girdling and Defoliation.

    Science.gov (United States)

    Jing, Yanli; Guan, Dexin; Wu, Jiabing; Wang, Anzhi; Jin, Changjie; Yuan, Fenghui

    2015-01-01

    Previous studies with different experimental methods have demonstrated that photosynthesis significantly influences soil respiration (RS). To compare the experimental results of different methods, RS after girdling and defoliation was measured in five-year-old seedlings of Fraxinus mandshurica from June to September. Girdling and defoliation significantly reduced RS by 33% and 25% within 4 days, and 40% and 32% within the entire treatment period, respectively. The differential response of RS to girdling and defoliation was a result of the over-compensation for RS after girdling and redistribution of stored carbon after defoliation. No significant effect on RS was observed between girdling and defoliation treatment, while the soluble sugar content in fine roots was higher in defoliation than in girdling treatment, indicating that defoliation had less compensation effect for RS after interrupting photosynthates supply. We confirm the close coupling of RS with photosynthesis and recommend defoliation for further studies to estimate the effect of photosynthesis on RS.

  11. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum

    Energy Technology Data Exchange (ETDEWEB)

    Albert, K.R.; Ro-Poulsen, H. (Univ. of Copenhagen, Dept. of Terrestrial Ecology, Copenhagen (DK)); Mikkelsen, T.N. (Technical Univ. of Denmark, Risoe National Laboratory for Sustainable Energy, Biosystems Dept., Roskilde (DK))

    2008-06-15

    An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis but also the effects on other parts of the photosynthetic machinery, e.g. the Calvin cycle, might be important. The 60% reduction of the UV-B irradiance used in this study implies a higher relative change in the UV-B load than many of the supplemental experiments do, but the substantial effect on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B. (au)

  12. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum.

    Science.gov (United States)

    Albert, Kristian R; Mikkelsen, Teis N; Ro-Poulsen, Helge

    2008-06-01

    An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis but also the effects on other parts of the photosynthetic machinery, e.g. the Calvin cycle, might be important. The 60% reduction of the UV-B irradiance used in this study implies a higher relative change in the UV-B load than many of the supplemental experiments do, but the substantial effect on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B.

  13. Effects of Kaolin Application on Light Absorption and Distribution, Radiation Use Efficiency and Photosynthesis of Almond and Walnut Canopies

    Science.gov (United States)

    Rosati, Adolfo; Metcalf, Samuel G.; Buchner, Richard P.; Fulton, Allan E.; Lampinen, Bruce D.

    2007-01-01

    Background and Aims Kaolin applied as a suspension to plant canopies forms a film on leaves that increases reflection and reduces absorption of light. Photosynthesis of individual leaves is decreased while the photosynthesis of the whole canopy remains unaffected or even increases. This may result from a better distribution of light within the canopy following kaolin application, but this explanation has not been tested. The objective of this work was to study the effects of kaolin application on light distribution and absorption within tree canopies and, ultimately, on canopy photosynthesis and radiation use efficiency. Methods Photosynthetically active radiation (PAR) incident on individual leaves within the canopy of almond (Prunus dulcis) and walnut (Juglans regia) trees was measured before and after kaolin application in order to study PAR distribution within the canopy. The PAR incident on, and reflected and transmitted by, the canopy was measured on the same day for kaolin-sprayed and control trees in order to calculate canopy PAR absorption. These data were then used to model canopy photosynthesis and radiation use efficiency by a simple method proposed in previous work, based on the photosynthetic response to incident PAR of a top-canopy leaf. Key Results Kaolin increased incident PAR on surfaces of inner-canopy leaves, although there was an estimated 20 % loss in PAR reaching the photosynthetic apparatus, due to increased reflection. Assuming a 20 % loss of PAR, modelled photosynthesis and photosynthetic radiation use efficiency (PRUE) of kaolin-coated leaves decreased by only 6·3 %. This was due to (1) more beneficial PAR distribution within the kaolin-sprayed canopy, and (2) with decreasing PAR, leaf photosynthesis decreases less than proportionally, due to the curvature of the photosynthesis response-curve to PAR. The relatively small loss in canopy PRUE (per unit of incident PAR), coupled with the increased incident PAR on the leaf surface on

  14. Expression profiling and functional analysis reveals that TOR is a key player in regulating photosynthesis and phytohormone signaling pathways in Arabidopsis.

    Science.gov (United States)

    Dong, Pan; Xiong, Fangjie; Que, Yumei; Wang, Kai; Yu, Lihua; Li, Zhengguo; Ren, Maozhi

    2015-01-01

    Target of rapamycin (TOR) acts as a master regulator to control cell growth by integrating nutrient, energy, and growth factors in all eukaryotic species. TOR plays an evolutionarily conserved role in regulating the transcription of genes associated with anabolic and catabolic processes in Arabidopsis, but little is known about the functions of TOR in photosynthesis and phytohormone signaling, which are unique features of plants. In this study, AZD8055 (AZD) was screened as the strongest active-site TOR inhibitor (asTORi) in Arabidopsis compared with TORIN1 and KU63794 (KU). Gene expression profiles were evaluated using RNA-seq after treating Arabidopsis seedlings with AZD. More than three-fold differentially expressed genes (DEGs) were identified in AZD-treated plants relative to rapamycin-treated plants in previous studies. Most of the DEGs and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways involved in cell wall elongation, ribosome biogenesis, and cell autophagy were common to both AZD- and rapamycin-treated samples, but AZD displayed much broader and more efficient inhibition of TOR compared with rapamycin. Importantly, the suppression of TOR by AZD resulted in remodeling of the expression profile of the genes associated with photosynthesis and various phytohormones, indicating that TOR plays a crucial role in modulating photosynthesis and phytohormone signaling in Arabidopsis. These newly identified DEGs expand the understanding of TOR signaling in plants. This study elucidates the novel functions of TOR in photosynthesis and phytohormone signaling and provides a platform to study the downstream targets of TOR in Arabidopsis.

  15. Songs about Cancer, Gene Expression, and the Biochemistry of Photosynthesis

    Science.gov (United States)

    Heineman, Richard H.

    2018-01-01

    These three biology songs can be used for educational purposes to teach about biochemical concepts. They touch on three different topics: (1) cancer progression and germ cells, (2) gene expression, promoters, and repressors, and (3) electronegativity and the biochemical basis of photosynthesis.

  16. Selective effects of H2O2 on cyanobacterial photosynthesis

    Czech Academy of Sciences Publication Activity Database

    Drábková, Michaela; Matthijs, H. C. P.; Admiraal, W.; Maršálek, Blahoslav

    2007-01-01

    Roč. 45, č. 3 (2007), s. 363-369 ISSN 0300-3604 Grant - others:-(XE) EVK2-CT-2002-57004 Institutional research plan: CEZ:AV0Z60050516 Keywords : hydrogen peroxide * cyanobacteria * photosynthesis Subject RIV: EF - Botanics Impact factor: 0.976, year: 2007

  17. Photosynthesis and sink activity of wasp-induced galls in Acacia pycnantha.

    Science.gov (United States)

    Dorchin, Netta; Cramer, Michael D; Hoffmann, John H

    2006-07-01

    Although insect galls are widely known to influence source-sink relationships in plants, the relationship between photosynthesis and gall activity has not been extensively studied. In this study we used 14CO2, photosynthesis, and respiration measurements to examine the capacity of bud galls induced by the wasp Trichilogaster signiventris (Pteromalidae) as carbon sinks in Acacia pycnantha. Galls of this species develop either in vegetative or reproductive buds, depending on the availability of tissues at different times of the year, and effectively eliminate seed production by the plant. Photosynthetic rates in phyllodes subtending clusters of galls were greater than rates in control phyllodes, a result we attributed to photosynthesis compensating for increased carbon demand by the galls. Contrary to previous studies, we found that photosynthesis within galls contributed substantially to the carbon budgets of the galls, particularly in large, mature galls, which exhibited lower specific respiration rates allowing for a net carbon gain in the light. To determine the sink capacity and competitive potential of galls, we measured the proportion of specific radioactivity in galls originating from either vegetative or reproductive buds and found no difference between them. The proportion of the total amount of phyllode-derived 14C accumulated in both clustered and solitary galls was less than that in fruits. Galls and fruits were predominantly reliant on subtending rather than on distant phyllodes for photosynthate. Solitary galls that developed in vegetative buds constituted considerably stronger sinks than galls in clusters on inflorescences where there was competition between galls or fruits for resources from the subtending phyllode. Wasps developing in solitary vegetative galls were correspondingly significantly larger than those from clustered galls. We conclude that, in the absence of inflorescence buds during summer and fall, the ability of the wasps to cause gall

  18. DNA sequence analysis of the photosynthesis region of Rhodobacter sphaeroides 2.4.1T

    OpenAIRE

    Choudhary, M.; Kaplan, Samuel

    2000-01-01

    This paper describes the DNA sequence of the photosynthesis region of Rhodobacter sphaeroides 2.4.1T. The photosynthesis gene cluster is located within a ~73 kb AseI genomic DNA fragment containing the puf, puhA, cycA and puc operons. A total of 65 open reading frames (ORFs) have been identified, of which 61 showed significant similarity to genes/proteins of other organisms while only four did not reveal any significant sequence similarity to any gene/protein sequences in the database. The da...

  19. Effect of traffic pollution on photosynthesis | Durrani | Journal of ...

    African Journals Online (AJOL)

    Vehicular exhaust is considered as one of the worst form of environmental pollution. To assess the effect of traffic pollution on photosynthesis, leaf samples of four different types of plants at different distances from the busy traffic road were collected from Wah. The samples consisted of sunny, shady and semi shady leaves of ...

  20. Streamflow, water quality, and constituent loads and yields, Scituate Reservoir drainage area, Rhode Island, water year 2013

    Science.gov (United States)

    Smith, Kirk P.

    2015-01-01

    Streamflow and concentrations of sodium and chloride estimated from records of specific conductance were used to calculate loads of sodium and chloride during water year (WY) 2013 (October 1, 2012, through September 30, 2013) for tributaries to the Scituate Reservoir, Rhode Island. Streamflow and water-quality data used in the study were collected by the U.S. Geological Survey (USGS) or the Providence Water Supply Board (PWSB) in the cooperative study. Streamflow was measured or estimated by the USGS following standard methods at 23 streamgages; 14 of these streamgages are equipped with instrumentation capable of continuously monitoring water level, specific conductance, and water temperature. Water-quality samples were collected at 37 sampling stations by the PWSB and at 14 continuous-record streamgages by the USGS during WY 2013 as part of a long-term sampling program; all stations are in the Scituate Reservoir drainage area. Water-quality data collected by the PWSB are summarized by using values of central tendency and are used, in combination with measured (or estimated) streamflows, to calculate loads and yields (loads per unit area) of selected water-quality constituents for WY 2013.