Transient release of oxygenated volatile organic compounds during light-dark transitions in Grey poplar leaves.
In this study, we investigated the prompt release of acetaldehyde and other oxygenated volatile organic compounds (VOCs) from leaves of Grey poplar [Populus x canescens (Aiton) Smith] following light-dark transitions. Mass scans utilizing the extremely fast and sensitive proton transfer reaction-mass spectrometry technique revealed the following temporal pattern after light-dark transitions: hexenal was emitted first, followed by acetaldehyde and other C(6)-VOCs. Under anoxic conditions, acetaldehyde was the only compound released after switching off the light. This clearly indicated that hexenal and other C(6)-VOCs were released from the lipoxygenase reaction taking place during light-dark transitions under aerobic conditions. Experiments with enzyme inhibitors that artificially increased cytosolic pyruvate demonstrated that the acetaldehyde burst after light-dark transition could not be explained by the recently suggested pyruvate overflow mechanism. The simulation of light fleck situations in the canopy by exposing leaves to alternating light-dark and dark-light transitions or fast changes from high to low photosynthetic photon flux density showed that this process is of minor importance for acetaldehyde emission into the Earth's atmosphere.
Graus
Martin
M
Institut für Ionenphysik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck, Austria.
Schnitzler
Jörg-Peter
JP
Hansel
Armin
A
Cojocariu
Cristian
C
Rennenberg
Heinz
H
Wisthaler
Armin
A
Kreuzwieser
Jürgen
J
D000079:Acetaldehyde / Q000378:metabolism*; D000332:Aerobiosis; D000693:Anaerobiosis; D003624:Darkness; D005740:Gases / Q000378:metabolism; D008027:Light; D009930:Organic Chemicals / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism*; D032107:Populus / Q000378:metabolism*; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism; D014835:Volatilization
D005740:Gases; D009930:Organic Chemicals; D011768:Pyruvate Dehydrogenase Complex; D000079:Acetaldehyde