Identification of volatile organic compounds emitted in the field by oilseed rape (Brassica napus ssp. oleifera) over the growing season

Abstract

Oilseed rape has been associated by rural dwellers with seasonal symptoms, such as sneezing, coughing, headache and eye irritation, during its flowering season, for a number of years. This study was performed to identify the volatile chemicals emitted from oilseed rape in the field. The objective of this study was to establish which volatile chemicals may be causative factors of oilseed rape allergy/toxicity. The volatile organic compounds were sampled over the flowering period using a modified entrainment technique for headspace analysis under field conditions. These volatiles were then identified using thermal desorption-gas chromatography-mass spectrometry. The major constituents identified were the monoterpenes limonene, sabinene, β-myrcene, and cis-3-hexen-1-ol acetate, a ‘green leaf’ volatile. The minor constituents included monoterpenes, sesquiterpenes, short chain aldehydes and ketones, other ‘green leaf’ volatiles and organic sulphides including the respiratory irritant, dimethyl disulphide. This report highlights the diversity of volatile chemicals emitted by oilseed rape and confirms field emissions to be broadly similar to those found previously in laboratory studies. A review is carried out on the scientific literature already published on oilseed rape flower headspace analysis.