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Resource capture by single leaves

Description: Leaves show a variety of strategies for maximizing CO{sub 2} and light capture. These are more meaningfully explained if they are considered in the context of maximizing capture relative to the utilization of water, nutrients and carbohydrates reserves. There is considerable variation between crops in their efficiency of CO{sub 2} and light capture at the leaf level. Understanding of these mechanisms indicate some ways in which efficiency of resource capture could be level cannot be meaningfull… more
Date: May 1, 1992
Creator: Long, S.P.
Partner: UNT Libraries Government Documents Department
open access

The bioenergetics of salt tolerance

Description: The aim of this project was to try to understand the adaptive mechanisms that organisms develop in order to respond to a sudden transformation in their environment to a salt shock.'' To study this problem we used a fresh water oxygenic photosynthetic cyanobacterium known as Synecoccus 6311. This organism suffers injury after this sudden exposure to high concentrations of sodium chloride equivalent to or even higher than that in sea water. Yet they are able to re-establish their photosynthetic a… more
Date: January 1, 1991
Creator: Packer, L.
Partner: UNT Libraries Government Documents Department
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Effects of energy related activities on the plankton of the Chesapeake Bay. Section 1. Progress report, 1 August 1976--30 September 1977

Description: Progress is reported on a comprehensive study of the ecology of the Chesapeake Bay estuary system. Emphasis is placed on seasonal variations of initial energy fixation by phytoplankton primary producers and subsequent energy transfer to herbivours and becterial heterotrophs. The impact of chemical and radioactive effluents from electric power plants on the ecology of Chesapeake Bay will be assessed. Data are included on the role of plankton metabolism in regenerating nutrients, nutrient exchang… more
Date: 1977~
Creator: Taft, Jay L.
Partner: UNT Libraries Government Documents Department
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Walker Branch Watershed: site description and research scope

Description: Walker Branch Watershed is located on the Oak Ridge Reservation in the Ridge and Valley section of Tennessee. The watershed (97 ha consisting of 2 subwatersheds) is underlain by Knox Dolomite; soils formed over the dolomitic substrate are deep, well-drained Typic Paleudults. The watershed is forested. The overstory is predominantly oak-hickory with lesser amounts of pine and mesic hardwoods. The Walker Branch Watershed Project was initiated in 1967 to: relate the productivity and water quality … more
Date: January 1, 1977
Creator: Harris, W. F.
Partner: UNT Libraries Government Documents Department
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Studies of air pollution effects on vegetation

Description: The report consists of three parts which summarize pollutant-vegetation effects research studies. These include: oxidant effects of primary productivity in ponderosa pine in the San Bernardino National Forest; air pollution effects on vegetation related to geothermal power development; and regional assessment of air pollution impact on vegetation by mathematical modeling. A list of publications that report results of the studies is included in an appendix.
Date: January 1, 1978
Partner: UNT Libraries Government Documents Department
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Life sciences

Description: This document is the 1989--1990 Annual Report for the Life Sciences Divisions of the University of California/Lawrence Berkeley Laboratory. Specific progress reports are included for the Cell and Molecular Biology Division, the Research Medicine and Radiation Biophysics Division (including the Advanced Light Source Life Sciences Center), and the Chemical Biodynamics Division. 450 refs., 46 figs. (MHB)
Date: April 1, 1991
Creator: Day, L.
Partner: UNT Libraries Government Documents Department
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Energetic control of intact chloroplast photosynthesis

Description: The induction phase of photosynthesis was studied in intact chloroplasts isolated from spinach. Within 15 sec of illumination, stromal ADP is phosphorylated to give an ATP/ADP ratio of 1.4. A transthylakoid pH gradient of about 4.1 units developed during the first min, and was associated with a low note of linear electron flow from H/sub 2/O to NADP/sup +/. In the following 2 to 3 min, both the pH gradient and ATP/ADP ratio declined to new steady state levels (3.9 pH units and a ratio of 0.9), … more
Date: unknown
Creator: Slovacek, R E & Hind, G
Partner: UNT Libraries Government Documents Department
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Vectorially photoinduced electron-transfer processes across water-in-oil interfaces of microemulsions

Description: Artificial photosynthetic devices are potential fuel sources. The basic idea in the design of such devices is a photosensitized electron-transfer that yields chemical species capable of reducing and oxidizing water to hydrogen and oxygen. A fundamental difficulty in effecting this transfer is the thermodynamically favored back reactions of the intermediary redox species. An interfacial model composed of a water-in-oil microemulsion is suggested to provide the separation of these redox species, … more
Date: July 1, 1980
Creator: Willner, I.; Otvos, J. W. & Calvin, M.
Partner: UNT Libraries Government Documents Department
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Post transcriptional regulation of chloroplast gene expression by nuclear encoded gene products

Description: The following is a review of research accomplished in the first two years of funding for the above mentioned project. The work performed is a molecular characterization of nuclear mutants of Chlamydomonas reinhardtii which are deficient in different stages in the post-transcriptional expression of a single chloroplast encoded polypeptide, the D2 protein of Photosystem II. Our long-term goals are to understand the molecular mechanisms by which nuclear gene products affect the expression of chlor… more
Date: January 1, 1992
Creator: Kuchka, Michael R.
Partner: UNT Libraries Government Documents Department
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Electron microscopy of hydrocarbon production in parthenium argentatum (guayule)

Description: The electron microscope was used to study the biological processes involved in hydrocarbon production. The little desert shrub Guayule (Parthenium argentatum) was selected for study. This shrub can produce hydrocarbons (rubber) in concentrations up to 1/4 of its dry weight. It grows on semi-arid land and has been extensively studied. The potential of Guayule is described in detail. Results of an investigation into the morphology of Guayule at the electron microscope level are given. Experiments… more
Date: November 1, 1977
Creator: Bauer, T.E.
Partner: UNT Libraries Government Documents Department
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Division of Energy Biosciences annual report and summaries of FY 1991 activities

Description: As a component of the Department of Energy, the Energy Biosciences (EB) program of the Office of Basic Energy Sciences supports long-term research aimed at addressing energy-related problems utilizing biological systems. There are three main components of the EB program. The first, Primary Biological Energy Conversion, concentrates on research on plant and microbial photosynthesis, but also deals with plant growth control, stress reactions, and interaction with pathogens. The second, Bioconvers… more
Date: September 1, 1991
Partner: UNT Libraries Government Documents Department
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Photochemistry and enzymology of photosynthesis. Progress report, November 1, 1979-March 31, 1980

Description: Progress is reported for the period November 1979 through March 1980. Specific projects reported on are: (1) light harvesting and electron transport in C/sub 4/ plants; (2) mass spectrometer studies of photosynthetic O/sub 2/ evolution; (3) biochemical studies on chloroplast copper proteins; and (4) electron transport in green plants. (ACR)
Date: April 1, 1980
Creator: Radmer, R.; Golbeck, J. & Velthuys, B.
Partner: UNT Libraries Government Documents Department
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Synthetic chloroplasts

Description: The principal function of the chloroplast is to capture solar quanta and to store them in some stable form. We are in the process of trying to construct a totally synthetic system that would simulate some of the reactions of the two photosystems which occur in natural chloroplasts. Toward this end, we have demonstrated a number of the reactions required in separated systems. We have shown that it is possible to transfer electrons across an insulating membrane barrier with a surfactant photosens… more
Date: June 1, 1980
Creator: Calvin, M.
Partner: UNT Libraries Government Documents Department
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Primary change separation and a biomimetic model of photosynthetic oxygen evolution

Description: The transformation of light into the chemical energy that drives the fixation of CO/sub 2/ and the evolution of O/sub 2/ in green plant photosynthesis is mediated by two photosystems (PS I and PS II). The initial photoreactions in both photosystems consist of the absorption of light by chlorophyll a (Chl a) and the subsequent formation of chlorophyll ..pi..-cation radicals by photoejection of electrons to nearby acceptors. The identity and chemical nature of the primary donor and acceptor of PS… more
Date: January 1, 1980
Creator: Davis, M S; Forman, A; Fujita, I; Netzel, T L & Fajer, J
Partner: UNT Libraries Government Documents Department
open access

High-flux solar photon processes

Description: This study was commissioned by the National Renewable Energy Laboratory (NREL) for the purpose of identifying high-flux photoprocesses that would lead to beneficial national and commercial applications. The specific focus on high-flux photoprocesses is based on the recent development by NREL of solar concentrator technology capable of delivering record flux levels. We examined photolytic and photocatalytic chemical processes as well as photothermal processes in the search for processes where co… more
Date: June 1, 1992
Creator: Lorents, D C; Narang, S; Huestis, D C; Mooney, J L; Mill, T; Song, H K et al.
Partner: UNT Libraries Government Documents Department
open access

Simulations of the carbon cycle in the oceans

Description: This study includes models of oceanic CO{sub 2} uptake. This perturbation simulation of carbon dioxide uptake gives strong support to estimates of oceanic uptake of fossil CO{sub 2} of order 2 GtC/yr. over the last decade. Carbon and carbon-nitrogen models are considered.
Date: January 1, 1992
Partner: UNT Libraries Government Documents Department
open access

Pigment-protein complexes

Description: The photosynthetically-active pigment protein complexes of procaryotes and eucaryotes include chlorophyll proteins, carotenochlorophyll proteins, and biliproteins. They are either integral components or attached to photosynthetic membranes. Detergents are frequently required to solubilize the pigment-protein complexes. The membrane localization and detergent solubilization strongly suggest that the pigment-protein complexes are bound to the membranes by hydrophobic interactions. Hydrophobic int… more
Date: January 1, 1980
Creator: Siegelman, H W
Partner: UNT Libraries Government Documents Department
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Energy transfer and utilization in biological systems. Final report, September 1, 1967--September 15, 1976. [Fluorescence studies of photosynthesis]

Description: In fluorescence studies of the photosynthetic process it was shown that the photosynthetic rate and light loss via chlorophyll fluorescence are strictly complementary. The exciplex state of matter responsible for most photochemistry was discovered and a wide variety of information about the state gained from studies of indole exciplexes. In addition to the nature of the bonding, degree of stability and general excited state behavior of indole exciplexes, their ability to lose electrons in a hig… more
Date: March 1, 1978
Creator: Lumry, R.W.
Partner: UNT Libraries Government Documents Department
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Picosecond electron transfer in diporphyrin models of Photosystem II of green plants

Description: Green plants and photosynthetic bacteria efficiently transform the energy of an absorbed photon into redox products. Current in vivo and in vitro studies on Photosystem II (PS II) suggest the electron donor is a chlorophyll monomer, ligated to produce the high oxidation potential of P680, and the electron acceptor is pheophytin, a metal-free chlorophyll. This study probes the behavior of this PS II model in solvents of high dielectric constant and tests the sensitivity of its charge transfer re… more
Date: January 1, 1980
Creator: Netzel, T L; Fujita, I; Wang, C B & Fajer, J
Partner: UNT Libraries Government Documents Department
open access

Report on picosecond studies of electron transfer in photosynthetic models

Description: Considerable spectroscopic work on reaction centers 8RC) from photosynthetic bacteria and on photosystem I (PSI) particles from green plants has established that the initial photochemical step in these systems is the subnanosecond tranfer of an electron resulting in the creation of an oxidized donor and a reduced acceptor. For both of these systems the electron donor is a dimer. The acceptor for bacterial RC's is bacteriopheophytin, a metal-free bacteriochlorophyll. The acceptor for PSI is… more
Date: January 1, 1980
Creator: Netzel, T L; Bucks, R R; Boxer, S G & Fujita, I
Partner: UNT Libraries Government Documents Department
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