IDENTIFICATION OF VOLATILES ORGANIC COMPOUNDS IN SOYBEAN FLOWERS BY HS-SPME-GC-MS

Abstract

Flowers release a variety of volatile organic compounds (VOCs) to attract pollinators. In soybean fields, bees are commonly observed foraging during the flowering, possibly attracted by visual and/or olfactory stimuli. Thus, the aim of this study was to identify the compounds produced by soybean cultivars with flowers with white and purple petals. The plants were grown in a greenhouse and the flowers collected and packed in headspace (HS) vials. For VOCs capture, the divinylbenzene/carboxene/polydimethylsiloxane SPME-fiber (DVB/CAR/PDMS) was used, and the analyses were performed on the gas chromatograph coupled to the mass spectrometer (GC-MS). In purple petal from the cultivars ‘BRS 399RR’, ‘BRS 1001IPRO’ and ‘Monsoy 6410IPRO’, 21, 39 and 35 COVs were detected, respectively. In white petals, 26 compounds were observed in ‘BRS 388 RR’, 24 in ‘DonMario 6563IPRO’ and 21 in ‘TMG 7063IPRO’. Chemometric analyses were performed and, based on PCA, PLS-DA and VIP, in all cultivars 2-hexenal; 1-hexanol; hexanal; 1-octen-3-ol; 1-hepten-3-one and furan, 2 -pentyl were detected. Multivariate statistical data showed that only 1-octen-3-ol was the compound with the highest intensity in relation to the other metabolites identified in soybean flowers. 1-hepten-one was the second compound with the largest chromatographic area, in purple petal cultivars, and 2-pentylfuran in white petal cultivars.1-Octen-3-ol was previously described in the literature as possessing stimulatory activity to Apis mellifera ligustica. Therefore, future studies of pollinator behaviour using the electroantennogram should be performed to understand the relationship of attractiveness and/or repellence to bees in response to VOCs released by soybean flowers.