Detection of Plant Volatiles after Leaf Wounding and Darkening by Proton Transfer Reaction “Time-of-Flight” Mass Spectrometry (PTR-TOF)

Abstract

Proton transfer reaction-time of flight (PTR-TOF) mass spectrometry was used to improve detection of biogenic volatiles organic compounds (BVOCs) induced by leaf wounding and darkening. PTR-TOF measurements unambiguously captured the kinetic of the large emissions of green leaf volatiles (GLVs) and acetaldehyde after wounding and darkening. GLVs emission correlated with the extent of wounding, thus confirming to be an excellent indicator of mechanical damage. Transient emissions of methanol, C5 compounds and isoprene from plant species that do not emit isoprene constitutively were also detected after wounding. In the strong isoprene-emitter Populus alba, light-dependent isoprene emission was sustained and even enhanced for hours after photosynthesis inhibition due to leaf cutting. Thus isoprene emission can uncouple from photosynthesis and may occur even after cutting leaves or branches, e.g., by agricultural practices or because of abiotic and biotic stresses. This observation may have important implications for assessments of isoprene sources and budget in the atmosphere, and consequences for tropospheric chemistry.

Off-season biogenic volatile organic compound emissions from heath mesocosms: responses to vegetation cutting

“…However, in contrast with the earlier studies reporting high emissions of C6 compounds (so called green leaf volatiles, GLVs) (Fall et al, 1999; Loreto et al, 2006; Brilli et al, 2011), the induced emissions here mainly consisted of C8-ketones, C8-alcohols and sesquiterpenes. The C8-compounds such as 1-octen-3-ol, 3-octanol, 3-octanone have common precursors with the commonly observed GLVs, namely linoleic and linolenic acid (Wurzenberger and Grosch, 1982; Hatanaka, 1993).…”

“…Cutting the aboveground vegetation caused large emission bursts, which is a common observation in response to mechanical wounding of plants (Fall et al, 1999; Loreto et al, 2006; Brilli et al, 2011). However, in contrast with the earlier studies reporting high emissions of C6 compounds (so called green leaf volatiles, GLVs) (Fall et al, 1999; Loreto et al, 2006; Brilli et al, 2011), the induced emissions here mainly consisted of C8-ketones, C8-alcohols and sesquiterpenes.…”

“…Studies using online monitoring by PTR-MS of BVOCs produced in connection with mechanical wounding of plants have shown that the instantaneous release of C6 aldehydes originating from membrane rupture and the consequent oxidation of unsaturated fatty acids shifts to the production of alcohols and acetates within a couple of minutes from wounding (Fall et al, 1999; Brilli et al, 2011). In this study, the BVOC measurement was started within 10 min from finishing the cutting, which means that the compounds immediately released from the ruptured plant tissues were most probably not caught by our measurements.…”

Photochemical reflectance index as an indirect estimator of foliar isoprenoid emissions at the ecosystem level

“…For instance, soil water deficits reduce photosynthetic carbon assimilation, whereas isoprene emissions can continue at a high level 52 . Light-dependent isoprene emission has been observed in leaves that have been severed at the stem and have ceased to photosynthesize 53,54 .…”

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

“…In addition, several C5 LOX products are emitted during some stresses such as wounding and leaf drying (Fall et al, 1999(Fall et al, , 2001Brilli et al, 2011). Parent ions of several C5 volatiles such as 1-penten-3-ol, 3-methylbutanal, and 2-methylbutanal have an m/z of 87+, but after water abstraction, they produce fragments with m/z of 69+ and are indistinguishable from isoprene in PTR-MS measurements.…”