RT journal article
T1 CO2 and O2 dynamics in leaves of aquatic plants with C3 or CAM photosynthesis-application of a novel CO2 microsensor
A1 Pedersen, Ole
A1 Colmer, Timothy D.
A1 García Robledo, Emilio Guillermo
A1 Revsbech, Niels Peter
A2 Biología
K1 Aerenchyma
K1 Crassulacean Acid Metabolism
K1 CO2  microelectrode
K1 leaf CO2  and O2
K1 Littorella uniflora
K1 Lobelia dortmanna
K1 plant submergence
K1 root radial O2  loss
K1 Severinghaus electrode
K1 sediment O2  consumption
K1 shore-weed
K1 underwater photosynthesis
AB Background and Aims Leaf tissue CO2 partial pressure (pCO2) shows contrasting dynamics over a diurnal cycle in C3 and Crassulacean Acid Metabolism (CAM) plants. However, simultaneous and continuous monitoring of pCO2 and pO2 in C3 and CAM plants under the same conditions was lacking. Our aim was to use a new CO2 microsensor and an existing O2 microsensor for non-destructive measurements of leaf pCO2 and pO2 dynamics to compare a C3 and a CAM plant in an aquatic environment. Methods A new amperometric CO2 microsensor and an O2 microsensor elucidated with high temporal resolution the dynamics in leaf pCO2 and pO2 during light-dark cycles for C3 Lobelia dortmanna and CAM Littorella uniflora aquatic plants. Underwater photosynthesis, dark respiration, tissue malate concentrations and sediment CO2 and O2 were also measured. Key Results During the dark period, for the C3 plant, pCO2 increased to approx. 3.5 kPa, whereas for the CAM plant CO2 was mostly below 0.05 kPa owing to CO2 sequestration into malate. Upon darkness, the CAM plant had an initial peak in pCO2 (approx. 0.16 kPa) which then declined to a quasi-steady state for several hours and then pCO2 increased towards the end of the dark period. The C3 plant became severely hypoxic late in the dark period, whereas the CAM plant with greater cuticle permeability did not. Upon illumination, leaf pCO2 declined and pO2 increased, although aspects of these dynamics also differed between the two plants. Conclusions The continuous measurements of pCO2 and pO2 highlighted the contrasting tissue gas compositions in submerged C3 and CAM plants. The CAM leaf pCO2 dynamics indicate an initial lag in CO2 sequestration to malate, which after several hours of malate synthesis then slows. Like the use of O2 microsensors to resolve questions related to plant aeration, deployment of the new CO2 microsensor will benefit plant ecophysiology research.
PB Oxford University Press
SN 1095-8290
YR 2018
FD 2018
LK http://hdl.handle.net/10498/32944
UL http://hdl.handle.net/10498/32944
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 13-nov-2026