Ozone induced emissions of biogenic VOC from tobacco: relationships between ozone uptake and emission of LOX products

Abstract

ABSTRACT Volatile organic compound (VOC) emissions from tobacco ( Nicotiana tabacum L. var. Bel W3) plants exposed to ozone (O 3 ) were investigated using proton‐transfer‐reaction mass‐spectrometry (PTR‐MS) and gas chromatography mass‐spectrometry (GC‐MS) to find a quantitative reference for plants’ responses to O 3 stress. O 3 exposures to illuminated plants induced post‐exposure VOC emission bursts. The lag time for the onset of volatile C 6 emissions produced within the octadecanoid pathway was found to be inversely proportional to O 3 uptake, or more precisely, to the O 3 flux density into the plants. In cases of short O 3 pulses of identical duration the total amount of these emitted C 6 VOC was related to the O 3 flux density into the plants, and not to ozone concentrations or dose–response relationships such as AOT 40 values. Approximately one C 6 product was emitted per five O 3 molecules taken up by the plant. A threshold flux density of O 3 inducing emissions of C 6 products was found to be (1.6 ± 0.7) × 10 −8 mol m −2 s −1 .