Chemotaxonomy vs Genotaxonomy of Viola genus: Can native volatile compounds of flowers be genuine tracers for violets differentiation?
Résumé
Violets are odorous flowers known in the Mediterranean basin since Antiquity and were a part of the first perfumes created. Toulouse has an historical relationship with this flower which is the symbol of the town and the home of the famous Viola Tolosa, Parma of Toulouse variety (Viola alba subsp. dehnhardtii). As a part of the regional Viola Tolosa project, a chemotaxonomy study of the hundred varieties/cultivars of violets belonging to the French Violet Conservatory hosted by the Toulouse Municipal Greenhouses will be set up. Based on headspace analysis of native volatile compounds emitted by flowers at maturity, dual chemical-sensory fingerprints were established for a rapid and efficient differentiation. A HS-SPME-GC/O method was used on two types of volatile samplings: an in-vivo and non-destructive analysis on the whole plant with the use of a bell-shaped glass covering to trap the volatiles as well as an ex-vivo analysis on the fresh cut flowers placed in a vial. First, experimental analytical conditions were optimized by experimental design methodology in order to determine the best suited protocols to obtain the richest volatile cocktails. Then optimized methods were applied to a sampling of ten plants of the collection selected according to the colour of flowers and their geographical origins. In parallel, genetic analyses were conducted on the same plants to confirm the putative varieties or cultivars. Finally, all the results were combined to match the chromatographic profiles with the genetic affiliation to a group. Acknowledgements: The Regional Council Languedoc-Roussillon Midi-Pyrénées (Project CLE ) for sponsoring 16