caa a22 4500 445892358 CHVBK 20180317145620.0 cr unu---uuuuu 170323e20110701xx s 000 0 eng 10.1007/s10750-011-0681-9 doi (NATIONALLICENCE)springer-10.1007/s10750-011-0681-9 Physiological responses of Spartina alterniflora to varying environmental conditions in Virginia marshes [Elektronische Daten] [James Kathilankal, Thomas Mozdzer, José Fuentes, Karen McGlathery, Paolo D'Odorico, Jay Zieman] Physiological measurements were used to investigate the dependence of photosynthesis on light, temperature, and intercellular carbon dioxide (CO2) levels in the C4 marsh grass Spartina alterniflora. Functional relationships between these environmental variables and S. alterniflora physiological responses were then used to improve C4-leaf photosynthesis models. Field studies were conducted in monocultures of S. alterniflora in Virginia, USA. On average, S. alterniflora exhibited lower light saturation values (~1000μmolm−2s−1) than observed in other C4 plants. Maximum carbon assimilation rates and stomatal conductance to water vapor diffusion were 36μmol (CO2) m−2s−1 and 200mmol (H2O)m−2s−1, respectively. Analysis of assimilation-intercellular CO2 and light response relationships were used to determine Arrhenius-type temperature functions for maximum rate of carboxylation (V cmax), phosphoenolpyruvate carboxylase activity (V pmax), and maximum electron transport rate (J max). Maximum V cmax values of 105μmolm−2s−1 were observed at the leaf temperature of 311K. Optimum V pmax values (80.6μmolm−2s−1) were observed at the foliage temperature of 308K. The observed V pmax values were lower than those in other C4 plants, whereas V cmax values were higher, and more representative of C3 plants. Optimum J max values reached 138μmol (electrons)m−2s−1 at the foliage temperature of 305K. In addition, the estimated CO2 compensation points were in the range of C3 or C3-C4 intermediate plants, not those typical of C4 plants. The present results indicate the possibility of a C3-C4 intermediate or C4-like photosynthetic mechanism rather than the expected C4-biochemical pathway in S. alterniflora under field conditions. In a scenario of atmospheric warming and increased atmospheric CO2 concentrations, S. alterniflora will likely respond positively to both changes. Such responses will result in increased S. alterniflora productivity, which is uncharacteristic of C4 plants. Springer Science+Business Media B.V., 2011 Salt marshes nationallicence Carbon cycling nationallicence Photosynthesis nationallicence Stomatal conductance nationallicence Environmental change nationallicence Sea level rise nationallicence Atmospheric warming nationallicence Stable carbon isotopes nationallicence Kathilankal James Li-Cor Inc., Biosciences Division, Lincoln, NB, USA aut Mozdzer Thomas Smithsonian Environmental Research Center, 21037, Edgewater, MD, USA aut Fuentes José Department of Meteorology, The Pennsylvania State University, 16802, University Park, PA, USA aut McGlathery Karen Department of Environmental Sciences, University of Virginia, 22904, Charlottesville, VA, USA aut D'Odorico Paolo Department of Environmental Sciences, University of Virginia, 22904, Charlottesville, VA, USA aut Zieman Jay Department of Environmental Sciences, University of Virginia, 22904, Charlottesville, VA, USA aut Hydrobiologia Springer Netherlands 669/1(2011-07-01), 167-181 0018-8158 669:1<167 2011 669 10750 https://doi.org/10.1007/s10750-011-0681-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10750-011-0681-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kathilankal James Li-Cor Inc., Biosciences Division, Lincoln, NB, USA aut NATIONALLICENCE 700 1- Mozdzer Thomas Smithsonian Environmental Research Center, 21037, Edgewater, MD, USA aut NATIONALLICENCE 700 1- Fuentes José Department of Meteorology, The Pennsylvania State University, 16802, University Park, PA, USA aut NATIONALLICENCE 700 1- McGlathery Karen Department of Environmental Sciences, University of Virginia, 22904, Charlottesville, VA, USA aut NATIONALLICENCE 700 1- D'Odorico Paolo Department of Environmental Sciences, University of Virginia, 22904, Charlottesville, VA, USA aut NATIONALLICENCE 700 1- Zieman Jay Department of Environmental Sciences, University of Virginia, 22904, Charlottesville, VA, USA aut NATIONALLICENCE 773 0- Hydrobiologia Springer Netherlands 669/1(2011-07-01), 167-181 0018-8158 669:1<167 2011 669 10750 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer