title: Long-chain (C19-C29) 1-chloro-n-alkanes in leaf waxes of halophytes of the Chenopodiaceae.
abstract: The hydrocarbon fraction of leaf waxes of three halophytes of the Chenopodiaceae common to Mediterranean salt marshes (Suaeda vera, Sarcocornia fruticosa and Halimione portulacoides) revealed the presence of a minor series of odd and even chains 1-chloro-n-alkanes ranging from C(19) to C(29). The identification of these new chlorinated plant constituents was based on a combination of mass spectrometry data with selective chlorine detection (CPG-AED) and was confirmed by comparison with authentic standards. The qualitative and quantitative distributions of these 1-chloro-n-alkanes varied inter-specifically. Homologues with an odd carbon-chain were predominant in all species but maximised at C(25) and C(27) in S. vera and S. fruticosa, and at C(27) and C(29) in H. portulacoides. Remarkably, 1-chloro-nonacosane was an abundant homologue only in this latter species. Leaves of S. vera contained 4 to 7 times more of total chloroalkanes than leaves of the other two species. These compounds accounted for 10, 4 and 1% of the hydrocarbon fraction of leaf waxes of S. vera, S. fruticosa and H. portulacoides, respectively. Attempts to link the occurrence of these chloroalkanes with other classes of leaf waxes (n-alkenes, n-aldehydes and n-alcohols) did not allowed a clear precursor-product relationship to be established. The biological functions as well as the mode of synthesis of alkylchlorides in (halophyte) plants remain unknown but undoubtedly deserve further attention.
authors.affiliation: Laboratoire d'Océanographie et de Biogéochimie (UMR CNRS 6535), Centre d'Océanologie de Marseille (OSU), Campus de Luminy, case 901, F-13288 Marseille, France. grossi@com.univ-mrs.fr
authors.forename: Vincent
authors.initials: V
authors.lastname: Grossi
authors.forename: Danielle
authors.initials: D
authors.lastname: Raphel
mesh_terms: D000473:Alkanes / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D019663:Chenopodiaceae / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D014885:Waxes / Q000737:chemistry*
chemical_list: D000473:Alkanes; D014885:Waxes