title: Glandular trichomes and essential oil composition of endemic Sideritis italica (Mill.) Greuter et Burdet from central Italy.
abstract: Sideritis italica (Mill.) Greuter et Burdet belongs to the Lamiaceae family and is endemic to Italy. The glandular trichomes (morphology, distribution, histochemistry, and ultrastructure) of the plant were studied for the first time, along with the chemical composition of the essential oils. Abundant non-glandular hairs and peltate (type A) and capitate (types B, C(1), and C(x)) glandular trichomes were observed both on the vegetative and reproductive organs. The histochemical procedures and the ultrastructural investigation enabled specific location of the main site of essential oil production mainly in type-A peltate hairs. Particular emphasis is given to the release mechanism of the secreted material in all of the types of glands, and the potential taxonomic value of the indumentum in the Lamiaceae family is briefly discussed. Essential oils were hydrodistilled from flowering aerial parts of S. italica, and 136 compounds (112 in flowerheads, 79 in vegetative parts) were identified. The quantitative prevalence of diterpenoids (43.4% in flowerheads and 22.3% in vegetative parts) was the most significant characteristic of the essential oil of S. italica that could be classified as a diterpene-rich essential oil according to the classification of Kirimer.
authors.affiliation: Department of Plant Biology, University of Florence, Florence.
authors.forename: Claudia
authors.initials: C
authors.lastname: Giuliani
authors.forename: Laura Maleci
authors.initials: LM
authors.lastname: Bini
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Papa
authors.forename: Gloria
authors.initials: G
authors.lastname: Cristalli
authors.forename: Gianni
authors.initials: G
authors.lastname: Sagratini
authors.forename: Sauro
authors.initials: S
authors.lastname: Vittori
authors.forename: Domenico
authors.initials: D
authors.lastname: Lucarini
authors.forename: Filippo
authors.initials: F
authors.lastname: Maggi
mesh_terms: D007558:Italy; D008855:Microscopy, Electron, Scanning; D009822:Oils, Volatile / Q000737:chemistry / Q000302:isolation & purification*; D035261:Plant Components, Aerial / Q000737:chemistry* / Q000254:growth & development / Q000648:ultrastructure; D010938:Plant Oils / Q000737:chemistry / Q000302:isolation & purification*; D031365:Sideritis / Q000737:chemistry* / Q000254:growth & development / Q000648:ultrastructure
chemical_list: D009822:Oils, Volatile; D010938:Plant Oils