Direct analysis of nectar and floral volatile organic compounds in hybrid onions by HS-SPME/GC?MS: Relationship with pollination and seed production

VERONICA CAROLINA SOTO VARGAS; IRMA B. MALDONADO; JOFRÉ, VIVIANA; GALMARINI, CLAUDIO; M. FERNANDA SILVA

MICROCHEMICAL JOURNAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 122 p. 110 - 118

0026-265X

In this study, a simple and solvent-free method using headspace solid-phase microextraction (SPME) and gaschromatography?mass spectrometry (GC?MS) was developed for determination of the volatile compoundsfromfresh flowers and nectar of male sterile and fertile lines of Alliumcepa L. The SPME parameters were studied;the optimum conditions of 85 μm carboxen/polydimethylsiloxane (CAR/PDMS), extraction temperature of 30 °Cand extraction time of 30 min were obtained. The analytical method was applied to characterize different onionlines according to the chemical composition of the volatile fraction of nectar and flowers. On the other hand, itwas determined which odor components contribute to the pollination of onions lines and relate the content ofspecific analytes with foraging behavior and seed production. More than 90 compounds were identified. Thesamples studied showed differences in the volatile profiles of flowers and nectar among the different lines. Theresults demonstrated that headspace SPME?GCMS is a simple, rapid and solvent-free method suitable foranalysis of volatile compounds emitted from onion plants. Furthermore, a great difference was found for thenumber of bee visits and seed yield among the onion lines analyzed. This study demonstrates that the combinationof chemical information and statistical analysis is able to differentiate onion male sterile lines from fertilelines, as well as among male sterile lines. Repellent compounds, such as dioxolanes, piperidines andorganosulfurs may contribute negatively to pollination, since the higher content of these analytes, the less beevisits and seed production yield.