title: Long-term photosynthetic response in single leaves of A C3 and C4 salt marsh species grown at elevated atmospheric CO2in situ.
abstract: Mono-specific communities of the C3sedge, Scirpus olneyi and the C4grass, Spartina patens, were exposed to normal ambient or elevated CO2, (ca. 680 μl l-1) throughout the 1987 and 1988 growing seasons in open-top field chambers located on a tidal marsh. Single stems of C3plants grown in ambient or elevated CO2showed an increased photosynthetic rate when tested at elevated CO2for both seasons. This increase in photosynthetic response in the C3species was maintained throughout the 1987 and 1988 growing season. The stimulation of photosynthesis with elevated CO2appeared to increase as temperature increased and decreased as photosynthetic photon flux (PPF) increased. Analysis of the photosynthetic response of the C3species during the 1988 season indicated that significant differences in light-saturated photosynthetic rate between ambient and elevated CO2conditions continued until October. In contrast to the C3sedge, the C4grass showed no significant photosynthetic increase to elevated CO2except at the beginning of the 1988 season.
authors.affiliation: Smithsonian Environmental Research Center, P.O. Box 28, 21037, Edgewater, MD, USA.
authors.forename: Lewis H
authors.initials: LH
authors.lastname: Ziska
authors.affiliation: Smithsonian Environmental Research Center, P.O. Box 28, 21037, Edgewater, MD, USA.
authors.forename: Bert G
authors.initials: BG
authors.lastname: Drake
authors.affiliation: Smithsonian Environmental Research Center, P.O. Box 28, 21037, Edgewater, MD, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Chamberlain
keywords: Acclimation; Elevated CO2; Photosynthetic photon flux; Scirpus olneyi; Spartina patens