Effects of heat and drought stress on post‐illumination bursts of volatile organic compounds in isoprene‐emitting and non‐emitting poplar

Abstract

Over the last decades, post‐illumination bursts (PIBs) of isoprene, acetaldehyde and green leaf volatiles (GLVs) following rapid light‐to‐dark transitions have been reported for a variety of different plant species. However, the mechanisms triggering their release still remain unclear. Here we measured PIBs of isoprene‐emitting (IE) and isoprene non‐emitting (NE) grey poplar plants grown under different climate scenarios (ambient control and three scenarios with elevated CO2 concentrations: elevated control, periodic heat and temperature stress, chronic heat and temperature stress, followed by recovery periods). PIBs of isoprene were unaffected by elevated CO2 and heat and drought stress in IE, while they were absent in NE plants. On the other hand, PIBs of acetaldehyde and also GLVs were strongly reduced in stress‐affected plants of all genotypes. After recovery from stress, distinct differences in PIB emissions in both genotypes confirmed different precursor pools for acetaldehyde and GLV emissions. Changes in PIBs of GLVs, almost absent in stressed plants and enhanced after recovery, could be mainly attributed to changes in lipoxygenase activity. Our results indicate that acetaldehyde PIBs, which recovered only partly, derive from a new mechanism in which acetaldehyde is produced from methylerythritol phosphate pathway intermediates, driven by deoxyxylulose phosphate synthase activity.

Total OH Reactivity Changes Over the Amazon Rainforest During an El Niño Event

“…The 2015 OH reactivity maximum occurred during the lightdark transition of sunset. Several studies have shown VOC bursts of isoprene, acetaldehyde, and/or (stress-related) greenleaf volatiles after light-dark transitions (Karl et al, 2002;Graus et al, 2004;Hayward et al, 2004;Brilli et al, 2011;Jardine et al, 2012;Jud et al, 2016). These so-called "post-illumination bursts" are thought to be associated with fast changes in intracellular pH in fast light-to-dark-transitions (Brilli et al, 2011), a "pyruvate overflow mechanism" (Karl et al, 2002;Hayward et al, 2004), or a "pyruvate dehydrogenase bypass pathway" (Jardine et al, 2012).…”

Host Selection, Oviposition and Feeding by a Phytopathogen Vector, Diaphorina citri (Hemiptera: Liviidae), Modulated by Plant Exposure to Formic Acid

“…Electroantennographic studies showed that formic and acetic acids elicit psyllid antennal responses (George et al, 2016), and act as phagostimulants that increase psyllid probing/feeding behavior (Lapointe et al, 2016). Other studies reported that photochemical oxidation of VOCs in general can lead to formation of a wide range of gaseous reaction or aerosol products (Bergström et al, 2014;Jud et al, 2016). These oxidative products may have ecological consequences for plantinsect interactions, when plant surfaces are exposed by gaseous contact or direct deposition.…”

The Uncertain Role of Biogenic VOC for Boundary-Layer Ozone Concentration: Example Investigation of Emissions from Two Forest Types with a Box Model

“…This effect is most likely due to the reduced availability of the substrate of the relevant biosynthetic pathways due to strongly impaired photosynthesis. In contrast, emission of stress-induced compounds, such as sesquiterpenes or green leaf volatiles (products of the lipoxygenase reaction) can increase in response to drought stress [65,72]. The results of our simulations could be affected by better considering the influence of drought and heat on BVOC emission, which most likely strongly depends on individual tree species' drought sensitivity.…”

“…Several studies have indicated that moderately reduced soil water availability does not affect or rather slightly stimulates isoprenoid emissions [65][66][67]. In contrast, strongly reduced water availability affects the biosynthesis of isoprenoids, thereby decreasing their emissions [66][67][68][69][70][71][72][73]. This effect is most likely due to the reduced availability of the substrate of the relevant biosynthetic pathways due to strongly impaired photosynthesis.…”