title: Isolation and characterization of allelopathic volatiles from mugwort (Artemisia vulgaris).
abstract: Several volatile allelochemicals were identified and characterized from fresh leaf tissue of three distinct populations of the invasive perennial weed, mugwort (Artemisia vulgaris). A unique bioassay was used to demonstrate the release of volatile allelochemicals from leaf tissues. Leaf volatiles were trapped and analyzed via gas chromatography coupled with mass spectrometry. Some of the components identified were terpenes, including camphor, eucalyptol, alpha-pinene, and beta-pinene. Those commercially available were tested individually to determine their phytotoxicity. Concentrations of detectable volatiles differed in both absolute and relative proportions among the mugwort populations. The three mugwort populations consisted of a taller, highly branched population (ITH-1); a shorter, lesser-branched population (ITH-2) (both grown from rhizome fragments from managed landscapes); and a population grown from seed with lobed leaves (VT). Considerable interspecific variation existed in leaf morphology and leaf surface chemistry. Bioassays revealed that none of the individual monoterpenes could account for the observed phytotoxicity imparted by total leaf volatiles, suggesting a synergistic effect or activity of a component not tested. Despite inability to detect a single dominant phytotoxic compound, decreases in total terpene concentration with increase in leaf age correlated with decreases in phytotoxicity. The presence of bioactive terpenoids in leaf surface chemistry of younger mugwort tissue suggests a potential role for terpenoids in mugwort establishment and proliferation in introduced habitats.
authors.affiliation: Department of Horticulture, Cornell University, Ithaca, New York 14853, USA. jnb22@cornell.edu
authors.forename: Jacob N
authors.initials: JN
authors.lastname: Barney
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Hay
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Weston
mesh_terms: D019306:Artemisia / Q000737:chemistry*; D000081008:Bicyclic Monoterpenes; D001643:Bridged Bicyclo Compounds / Q000302:isolation & purification / Q000633:toxicity; D002164:Camphor / Q000302:isolation & purification / Q000633:toxicity; D003511:Cyclohexanols / Q000302:isolation & purification / Q000633:toxicity; D000077591:Eucalyptol; D008401:Gas Chromatography-Mass Spectrometry; D039821:Monoterpenes / Q000302:isolation & purification* / Q000633:toxicity; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000033:anatomy & histology / Q000737:chemistry* / Q000254:growth & development; D018517:Plant Roots / Q000737:chemistry / Q000254:growth & development; D010946:Plants, Medicinal; D011157:Population Dynamics; D012639:Seeds / Q000254:growth & development; D014835:Volatilization
chemical_list: D000081008:Bicyclic Monoterpenes; D001643:Bridged Bicyclo Compounds; D003511:Cyclohexanols; D039821:Monoterpenes; D010936:Plant Extracts; C010789:beta-pinene; D002164:Camphor; C005451:alpha-pinene; D000077591:Eucalyptol