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.
Institut für Ionenphysik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck, Austria.
Martin
M
Graus
Jörg-Peter
JP
Schnitzler
Armin
A
Hansel
Cristian
C
Cojocariu
Heinz
H
Rennenberg
Armin
A
Wisthaler
Jürgen
J
Kreuzwieser
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