Photosynthesis

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Gerald E Edwards - One of the best experts on this subject based on the ideXlab platform.

  • kranz anatomy is not essential for terrestrial c4 plant Photosynthesis
    Nature, 2001
    Co-Authors: Elena V Voznesenskaya, Vincent R. Franceschi, Olavi Kiirats, Helmut Freitag, Gerald E Edwards
    Abstract:

    An important adaptation to CO2-limited Photosynthesis in cyanobacteria, algae and some plants was development of CO2-concentrating mechanisms (CCM). Evolution of a CCM occurred many times in flowering plants, beginning at least 15-20 million years ago, in response to atmospheric CO2 reduction, climate change, geological trends, and evolutionary diversification of species. In plants, this is achieved through a biochemical inorganic carbon pump called C4 Photosynthesis, discovered 35 years ago. C4 Photosynthesis is advantageous when limitations on carbon acquisition are imposed by high temperature, drought and saline conditions. It has been thought that a specialized leaf anatomy, composed of two, distinctive photosynthetic cell types (Kranz anatomy), is required for C4 Photosynthesis. We provide evidence that C4 Photosynthesis can function within a single photosynthetic cell in terrestrial plants. Borszczowia aralocaspica (Chenopodiaceae) has the photosynthetic features of C4 plants, yet lacks Kranz anatomy. This species accomplishes C4 Photosynthesis through spatial compartmentation of photosynthetic enzymes, and by separation of two types of chloroplasts and other organelles in distinct positions within the chlorenchyma cell cytoplasm.

  • occurrence of c3 and c4 Photosynthesis in cotyledons and leaves of salsola species chenopodiaceae
    Photosynthesis Research, 2000
    Co-Authors: Vladimir I Pyankov, Vincent R. Franceschi, Elena V Voznesenskaya, Clanton C Black, Alexander N Kuzmin, Eric Ganko, Gerald E Edwards
    Abstract:

    Most species of the genus Salsola (Chenopodiaceae) that have been examined exhibit C4 Photosynthesis in leaves. Four Salsola species from Central Asia were investigated in this study to determine the structural and functional relationships in Photosynthesis of cotyledons compared to leaves, using anatomical (Kranz versus non-Kranz anatomy, chloroplast ultrastructure) and biochemical (activities of photosynthetic enzymes of the C3 and C4 pathways, 14C labeling of primary Photosynthesis products and 13C/12C carbon isotope fractionation) criteria. The species included S. paulsenii from section Salsola, S. richteri from section Coccosalsola, S. laricina from section Caroxylon, and S. gemmascens from section Malpigipila. The results show that all four species have a C4 type of Photosynthesis in leaves with a Salsoloid type Kranz anatomy, whereas both C3 and C4 types of Photosynthesis were found in cotyledons. S. paulsenii and S. richteri have NADP- (NADP-ME) C4 type biochemistry with Salsoloid Kranz anatomy in both leaves and cotyledons. In S. laricina, both cotyledons and leaves have NAD-malic enzyme (NAD-ME) C4 type Photosynthesis; however, while the leaves have Salsoloid type Kranz anatomy, cotyledons have Atriplicoid type Kranz anatomy. In S. gemmascens, cotyledons exhibit C3 type Photosynthesis, while leaves perform NAD-ME type Photosynthesis. Since the four species studied belong to different Salsola sections, this suggests that differences in photosynthetic types of leaves and cotyledons may be used as a basis or studies of the origin and evolution of C4 Photosynthesis in the family Chenopodiaceae.

  • occurrence of c 3 and c 4 Photosynthesis in cotyledons and leaves of salsola species chenopodiaceae
    Photosynthesis Research, 2000
    Co-Authors: Vladimir I Pyankov, Vincent R. Franceschi, Elena V Voznesenskaya, Clanton C Black, Alexander N Kuzmin, Eric Ganko, Gerald E Edwards
    Abstract:

    Most species of the genus Salsola (Chenopodiaceae) that have been examined exhibit C4 Photosynthesis in leaves. Four Salsola species from Central Asia were investigated in this study to determine the structural and functional relationships in Photosynthesis of cotyledons compared to leaves, using anatomical (Kranz versus non-Kranz anatomy, chloroplast ultrastructure) and biochemical (activities of photosynthetic enzymes of the C3 and C4 pathways, 14C labeling of primary Photosynthesis products and 13C/12C carbon isotope fractionation) criteria. The species included S. paulsenii from section Salsola, S. richteri from section Coccosalsola, S. laricina from section Caroxylon, and S. gemmascens from section Malpigipila. The results show that all four species have a C4 type of Photosynthesis in leaves with a Salsoloid type Kranz anatomy, whereas both C3 and C4 types of Photosynthesis were found in cotyledons. S. paulsenii and S. richteri have NADP- (NADP-ME) C4 type biochemistry with Salsoloid Kranz anatomy in both leaves and cotyledons. In S. laricina, both cotyledons and leaves have NAD-malic enzyme (NAD-ME) C4 type Photosynthesis; however, while the leaves have Salsoloid type Kranz anatomy, cotyledons have Atriplicoid type Kranz anatomy. In S. gemmascens, cotyledons exhibit C3 type Photosynthesis, while leaves perform NAD-ME type Photosynthesis. Since the four species studied belong to different Salsola sections, this suggests that differences in photosynthetic types of leaves and cotyledons may be used as a basis or studies of the origin and evolution of C4 Photosynthesis in the family Chenopodiaceae.

Liisa Kulmala - One of the best experts on this subject based on the ideXlab platform.

  • inter and intra annual dynamics of Photosynthesis differ between forest floor vegetation and tree canopy in a subarctic scots pine stand
    Agricultural and Forest Meteorology, 2019
    Co-Authors: Pasi Kolari, Jukka Pumpanen, Liisa Kulmala, Sigrid Dengel, Frank Berninger, Kajar Koster, Laura Matkala, Anni Vanhatalo, Timo Vesala
    Abstract:

    Abstract We studied the inter- and intra-annual dynamics of the Photosynthesis of forest floor vegetation and tree canopy in a subarctic Scots pine stand at the northern timberline in Finland. We tackled the issue using three different approaches: 1) measuring carbon dioxide exchange above and below canopy with the eddy covariance technique, 2) modelling the Photosynthesis of the tree canopy based on shoot chamber measurements, and 3) upscaling the forest floor Photosynthesis using biomass estimates and available information on the annual cycle of photosynthetic capacity of those species. The studied ecosystem was generally a weak sink of carbon but the sink strength showed notable year-to-year variation. Total ecosystem respiration and Photosynthesis indicated a clear temperature limitation for the carbon exchange. However, the increase in photosynthetic production was steeper than the increase in respiration with temperature, indicating that warm temperatures increase the sink strength and do not stimulate the total ecosystem respiration as much in the 4-year window studied. The interannual variation in the photosynthetic production of the forest stand mainly resulted from the forest floor vegetation, whereas the Photosynthesis of the tree canopy seemed to be more stable from year to year. Tree canopy Photosynthesis increased earlier in the spring, whereas that of the forest floor increased after snowmelt, highlighting that models for Photosynthesis in the northern area should also include snow cover in order to accurately estimate the seasonal dynamics of Photosynthesis in these forests.

Clanton C Black - One of the best experts on this subject based on the ideXlab platform.

  • crassulacean acid metabolism Photosynthesis working the night shift
    Photosynthesis Research, 2003
    Co-Authors: Clanton C Black, Barry C Osmond
    Abstract:

    Crassulacean acid metabolism (CAM) can be traced from Roman times through persons who noted a morning acid taste of some common house plants. From India in 1815, Benjamin-Heyne described a ‘daily acid taste cycle’ with some succulent garden plants. Recent work has shown that the nocturnally formed acid is decarboxylated during the day to become the CO2 for Photosynthesis. Thus, CAM Photosynthesis extends over a 24-hour day using several daily interlocking cycles. To understand CAM Photosynthesis, several landmark discoveries were made at the following times: daily reciprocal acid and carbohydrate cycles were found during 1870 to 1887; their precise identification, as malic acid and starch, and accurate quantification occurred from 1940 to 1954; diffusive gas resistance methods were introduced in the early 1960s that led to understanding the powerful stomatal control of daily gas exchanges; C4 Photosynthesis in two different types of cells was discovered from 1965 to ∼1974 and the resultant information was used to elucidate the day and night portions of CAM Photosynthesis in one cell; and exceptionally high internal green tissue CO2 levels, 0.2 to 2.5%, upon the daytime decarboxylation of malic acid, were discovered in 1979. These discoveries then were combined with related information from C3 and C4 Photosynthesis, carbon biochemistry, cellular anatomy, and ecological physiology. Therefore by ∼1980, CAM Photosynthesis finally was rigorously outlined. In a nutshell, 24-hour CAM occurs by phosphoenol pyruvate (PEP) carboxylase fixing CO2(HCO3 −) over the night to form malic acid that is stored in plant cell vacuoles. While stomata are tightly closed the following day, malic acid is decarboxylated releasing CO2 for C3 Photosynthesis via ribulose bisphosphate carboxylase oxygenase (Rubisco). The CO2 acceptor, PEP, is formed via glycolysis at night from starch or other stored carbohydrates and after decarboxylation the three carbons are restored each day. In mid to late afternoon the stomata can open and mostly C3 Photosynthesis occurs until darkness. CAM Photosynthesis can be both inducible and constitutive and is known in 33 families with an estimated 15 to 20 000 species. CAM plants express the most plastic and tenacious Photosynthesis known in that they can switch Photosynthesis pathways and they can live and conduct Photosynthesis for years even in the virtual absence of external H2O and CO2, i.e., CAM tenaciously protects its Photosynthesis from both H2O and CO2 stresses.

  • occurrence of c3 and c4 Photosynthesis in cotyledons and leaves of salsola species chenopodiaceae
    Photosynthesis Research, 2000
    Co-Authors: Vladimir I Pyankov, Vincent R. Franceschi, Elena V Voznesenskaya, Clanton C Black, Alexander N Kuzmin, Eric Ganko, Gerald E Edwards
    Abstract:

    Most species of the genus Salsola (Chenopodiaceae) that have been examined exhibit C4 Photosynthesis in leaves. Four Salsola species from Central Asia were investigated in this study to determine the structural and functional relationships in Photosynthesis of cotyledons compared to leaves, using anatomical (Kranz versus non-Kranz anatomy, chloroplast ultrastructure) and biochemical (activities of photosynthetic enzymes of the C3 and C4 pathways, 14C labeling of primary Photosynthesis products and 13C/12C carbon isotope fractionation) criteria. The species included S. paulsenii from section Salsola, S. richteri from section Coccosalsola, S. laricina from section Caroxylon, and S. gemmascens from section Malpigipila. The results show that all four species have a C4 type of Photosynthesis in leaves with a Salsoloid type Kranz anatomy, whereas both C3 and C4 types of Photosynthesis were found in cotyledons. S. paulsenii and S. richteri have NADP- (NADP-ME) C4 type biochemistry with Salsoloid Kranz anatomy in both leaves and cotyledons. In S. laricina, both cotyledons and leaves have NAD-malic enzyme (NAD-ME) C4 type Photosynthesis; however, while the leaves have Salsoloid type Kranz anatomy, cotyledons have Atriplicoid type Kranz anatomy. In S. gemmascens, cotyledons exhibit C3 type Photosynthesis, while leaves perform NAD-ME type Photosynthesis. Since the four species studied belong to different Salsola sections, this suggests that differences in photosynthetic types of leaves and cotyledons may be used as a basis or studies of the origin and evolution of C4 Photosynthesis in the family Chenopodiaceae.

  • occurrence of c 3 and c 4 Photosynthesis in cotyledons and leaves of salsola species chenopodiaceae
    Photosynthesis Research, 2000
    Co-Authors: Vladimir I Pyankov, Vincent R. Franceschi, Elena V Voznesenskaya, Clanton C Black, Alexander N Kuzmin, Eric Ganko, Gerald E Edwards
    Abstract:

    Most species of the genus Salsola (Chenopodiaceae) that have been examined exhibit C4 Photosynthesis in leaves. Four Salsola species from Central Asia were investigated in this study to determine the structural and functional relationships in Photosynthesis of cotyledons compared to leaves, using anatomical (Kranz versus non-Kranz anatomy, chloroplast ultrastructure) and biochemical (activities of photosynthetic enzymes of the C3 and C4 pathways, 14C labeling of primary Photosynthesis products and 13C/12C carbon isotope fractionation) criteria. The species included S. paulsenii from section Salsola, S. richteri from section Coccosalsola, S. laricina from section Caroxylon, and S. gemmascens from section Malpigipila. The results show that all four species have a C4 type of Photosynthesis in leaves with a Salsoloid type Kranz anatomy, whereas both C3 and C4 types of Photosynthesis were found in cotyledons. S. paulsenii and S. richteri have NADP- (NADP-ME) C4 type biochemistry with Salsoloid Kranz anatomy in both leaves and cotyledons. In S. laricina, both cotyledons and leaves have NAD-malic enzyme (NAD-ME) C4 type Photosynthesis; however, while the leaves have Salsoloid type Kranz anatomy, cotyledons have Atriplicoid type Kranz anatomy. In S. gemmascens, cotyledons exhibit C3 type Photosynthesis, while leaves perform NAD-ME type Photosynthesis. Since the four species studied belong to different Salsola sections, this suggests that differences in photosynthetic types of leaves and cotyledons may be used as a basis or studies of the origin and evolution of C4 Photosynthesis in the family Chenopodiaceae.

Rowan F Sage - One of the best experts on this subject based on the ideXlab platform.

  • is c4 Photosynthesis less phenotypically plastic than c3 Photosynthesis
    Journal of Experimental Botany, 2006
    Co-Authors: Rowan F Sage, Athena D Mckown
    Abstract:

    C4 Photosynthesis is a complex specialization that enhances carbon gain in hot, often arid habitats where photorespiration rates can be high. Certain features unique to C4 Photosynthesis may reduce the potential for phenotypic plasticity and photosynthetic acclimation to environmental change relative to what is possible with C3 Photosynthesis. During acclimation, the structural and physiological integrity of the mesophyll-bundle sheath (M-BS) complex has to be maintained if C4 Photosynthesis is to function efficiently in the new environment. Disruption of the M-BS structure could interfere with metabolic co-ordination between the C3 and C4 cycles, decrease metabolite flow rate between the tissues, increase CO2 leakage from the bundle sheath, and slow enzyme activity. C4 plants have substantial acclimation potential, but in most cases lag behind the acclimation responses in C3 plants. For example, some C4 species are unable to maintain high quantum yields when grown in low-light conditions. Others fail to reduce carboxylase content in shade, leaving substantial over-capacity of Rubisco and PEP carboxylase in place. Shade-tolerant C4 grasses lack the capacity for maintaining a high state of photosynthetic induction following sunflecks, and thus may be poorly suited to exploit subsequent sunflecks compared with C3 species. In total, the evidence indicates that C4 Photosynthesis is less phenotypically plastic than C3 Photosynthesis, and this may contribute to the more restricted ecological and geographical distribution of C4 plants across the Earth.

  • the evolution of c4 Photosynthesis
    New Phytologist, 2004
    Co-Authors: Rowan F Sage
    Abstract:

    Contents Summary 341 I.  Introduction 342 II.  What is C4 Photosynthesis? 343 III.  Why did C4 Photosynthesis evolve? 347 IV.  Evolutionary lineages of C4 Photosynthesis 348 V.  Where did C4 Photosynthesis evolve? 350 VI.  How did C4 Photosynthesis evolve? 352 VII.  Molecular evolution of C4 Photosynthesis 361 VIII. When did C4 Photosynthesis evolve 362 IX.  The rise of C4 Photosynthesis in relation to climate and CO2 363 X.  Final thoughts: the future evolution of C4 Photosynthesis 365 Acknowledgements 365 References 365 Summary C4 Photosynthesis is a series of anatomical and biochemical modifications that concentrate CO2 around the carboxylating enzyme Rubisco, thereby increasing photosynthetic efficiency in conditions promoting high rates of photorespiration. The C4 pathway independently evolved over 45 times in 19 families of angiosperms, and thus represents one of the most convergent of evolutionary phenomena. Most origins of C4 Photosynthesis occurred in the dicots, with at least 30 lineages. C4 Photosynthesis first arose in grasses, probably during the Oligocene epoch (24–35 million yr ago). The earliest C4 dicots are likely members of the Chenopodiaceae dating back 15–21 million yr; however, most C4 dicot lineages are estimated to have appeared relatively recently, perhaps less than 5 million yr ago. C4 Photosynthesis in the dicots originated in arid regions of low latitude, implicating combined effects of heat, drought and/or salinity as important conditions promoting C4 evolution. Low atmospheric CO2 is a significant contributing factor, because it is required for high rates of photorespiration. Consistently, the appearance of C4 plants in the evolutionary record coincides with periods of increasing global aridification and declining atmospheric CO2. Gene duplication followed by neo- and nonfunctionalization are the leading mechanisms for creating C4 genomes, with selection for carbon conservation traits under conditions promoting high photorespiration being the ultimate factor behind the origin of C4 Photosynthesis.

Elena V Voznesenskaya - One of the best experts on this subject based on the ideXlab platform.

  • kranz anatomy is not essential for terrestrial c4 plant Photosynthesis
    Nature, 2001
    Co-Authors: Elena V Voznesenskaya, Vincent R. Franceschi, Olavi Kiirats, Helmut Freitag, Gerald E Edwards
    Abstract:

    An important adaptation to CO2-limited Photosynthesis in cyanobacteria, algae and some plants was development of CO2-concentrating mechanisms (CCM). Evolution of a CCM occurred many times in flowering plants, beginning at least 15-20 million years ago, in response to atmospheric CO2 reduction, climate change, geological trends, and evolutionary diversification of species. In plants, this is achieved through a biochemical inorganic carbon pump called C4 Photosynthesis, discovered 35 years ago. C4 Photosynthesis is advantageous when limitations on carbon acquisition are imposed by high temperature, drought and saline conditions. It has been thought that a specialized leaf anatomy, composed of two, distinctive photosynthetic cell types (Kranz anatomy), is required for C4 Photosynthesis. We provide evidence that C4 Photosynthesis can function within a single photosynthetic cell in terrestrial plants. Borszczowia aralocaspica (Chenopodiaceae) has the photosynthetic features of C4 plants, yet lacks Kranz anatomy. This species accomplishes C4 Photosynthesis through spatial compartmentation of photosynthetic enzymes, and by separation of two types of chloroplasts and other organelles in distinct positions within the chlorenchyma cell cytoplasm.

  • occurrence of c3 and c4 Photosynthesis in cotyledons and leaves of salsola species chenopodiaceae
    Photosynthesis Research, 2000
    Co-Authors: Vladimir I Pyankov, Vincent R. Franceschi, Elena V Voznesenskaya, Clanton C Black, Alexander N Kuzmin, Eric Ganko, Gerald E Edwards
    Abstract:

    Most species of the genus Salsola (Chenopodiaceae) that have been examined exhibit C4 Photosynthesis in leaves. Four Salsola species from Central Asia were investigated in this study to determine the structural and functional relationships in Photosynthesis of cotyledons compared to leaves, using anatomical (Kranz versus non-Kranz anatomy, chloroplast ultrastructure) and biochemical (activities of photosynthetic enzymes of the C3 and C4 pathways, 14C labeling of primary Photosynthesis products and 13C/12C carbon isotope fractionation) criteria. The species included S. paulsenii from section Salsola, S. richteri from section Coccosalsola, S. laricina from section Caroxylon, and S. gemmascens from section Malpigipila. The results show that all four species have a C4 type of Photosynthesis in leaves with a Salsoloid type Kranz anatomy, whereas both C3 and C4 types of Photosynthesis were found in cotyledons. S. paulsenii and S. richteri have NADP- (NADP-ME) C4 type biochemistry with Salsoloid Kranz anatomy in both leaves and cotyledons. In S. laricina, both cotyledons and leaves have NAD-malic enzyme (NAD-ME) C4 type Photosynthesis; however, while the leaves have Salsoloid type Kranz anatomy, cotyledons have Atriplicoid type Kranz anatomy. In S. gemmascens, cotyledons exhibit C3 type Photosynthesis, while leaves perform NAD-ME type Photosynthesis. Since the four species studied belong to different Salsola sections, this suggests that differences in photosynthetic types of leaves and cotyledons may be used as a basis or studies of the origin and evolution of C4 Photosynthesis in the family Chenopodiaceae.

  • occurrence of c 3 and c 4 Photosynthesis in cotyledons and leaves of salsola species chenopodiaceae
    Photosynthesis Research, 2000
    Co-Authors: Vladimir I Pyankov, Vincent R. Franceschi, Elena V Voznesenskaya, Clanton C Black, Alexander N Kuzmin, Eric Ganko, Gerald E Edwards
    Abstract:

    Most species of the genus Salsola (Chenopodiaceae) that have been examined exhibit C4 Photosynthesis in leaves. Four Salsola species from Central Asia were investigated in this study to determine the structural and functional relationships in Photosynthesis of cotyledons compared to leaves, using anatomical (Kranz versus non-Kranz anatomy, chloroplast ultrastructure) and biochemical (activities of photosynthetic enzymes of the C3 and C4 pathways, 14C labeling of primary Photosynthesis products and 13C/12C carbon isotope fractionation) criteria. The species included S. paulsenii from section Salsola, S. richteri from section Coccosalsola, S. laricina from section Caroxylon, and S. gemmascens from section Malpigipila. The results show that all four species have a C4 type of Photosynthesis in leaves with a Salsoloid type Kranz anatomy, whereas both C3 and C4 types of Photosynthesis were found in cotyledons. S. paulsenii and S. richteri have NADP- (NADP-ME) C4 type biochemistry with Salsoloid Kranz anatomy in both leaves and cotyledons. In S. laricina, both cotyledons and leaves have NAD-malic enzyme (NAD-ME) C4 type Photosynthesis; however, while the leaves have Salsoloid type Kranz anatomy, cotyledons have Atriplicoid type Kranz anatomy. In S. gemmascens, cotyledons exhibit C3 type Photosynthesis, while leaves perform NAD-ME type Photosynthesis. Since the four species studied belong to different Salsola sections, this suggests that differences in photosynthetic types of leaves and cotyledons may be used as a basis or studies of the origin and evolution of C4 Photosynthesis in the family Chenopodiaceae.