Transient Release of Oxygenated Volatile Organic Compounds during Light-Dark Transitions in Grey Poplar Leaves

Abstract

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 C6-VOCs. Under anoxic conditions, acetaldehyde was the only compound released after switching off the light. This clearly indicated that hexenal and other C6-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.

Chemical sensing of plant stress at the ecosystem scale

“…The correlation coefficient between C 6 wound VOCs and MeSA noontime fluxes was 0.82. C 6 wound VOCs such as 3-Z-hexenal are commonly observed when lipids are damaged and have been detected during mechanical wounding (Fall et al, 1999), herbivore infestations (Arimura et al, 2005), freezing ) and drying ) events, acute ozone exposure (Heiden et al, 1999) and after drastic changes of a plant's light environment (Graus et al, 2004). From Fig.…”

The bi-directional exchange of oxygenated VOCs between a loblolly pine (<I>Pinus taeda</I>) plantation and the atmosphere

“…The temperature dependence points toward competing enzyme reactions similar as observed for CO 2 uptake in plants. Multiple competing enzyme reactions involved with acetaldehyde metabolisms in plants have been proposed in previous studies (Kreuzwieser et al, 2000;Karl et al, 2002a;Graus et al, 2004). The production rate per ppb of acetaldehyde (slope in Fig.…”

“…While acetone is believed to originate from cyanogenesis and the decarboxylation of acetoacetate, acetaldehyde has been shown to be emitted as a result of the oxidation of ethanol arising in anoxic tissues (Kreuzwieser et al, 2000). Labeling studies using 13 C suggest that acetaldehyde can also originate from recently fixed carbon and could be produced from cytosolic pyruvate, which could trigger its formation under rapidly changing light conditions (Karl et al, 2002a;Graus et al, 2004) have hypothesized that Acetyl-Co A might also be linked to the production of acetaldehyde and related to wound VOCs Hatanaka, 1996).…”

Bisphosphonate Inhibitors Reveal a Large Elasticity of Plastidic Isoprenoid Synthesis Pathway in Isoprene-Emitting Hybrid Aspen

“…CO 2 concentration was measured by an LI-6251 infrared gas analyzer (LI-Cor, Inc.), water vapor concentration by a custom-made micropsychrometer, and isoprene concentration (protonated parent ion with mass-to-charge ratio [m/z] of 69+) by PTR-MS (high-sensitivity version with a response time of approximately 0.1 s; Ionicon Analytik GmbH). Protonated ions corresponding to the main fragments of LOX pathway volatiles, hexenals (m/z = 81+), and other C6 volatiles (m/z = 83+, sum of hexenols, hexanal, and hexenyl acetates) and protonated parent ions corresponding to monoterpenes (m/z = 137+) were also recorded (Graus et al, 2004;Rasulov et al, 2014). A standard gas containing a spectrum of key volatiles (Ionimed GmbH) was used to calibrate PTR-MS.…”