title: Induction of stress volatiles and changes in essential oil content and composition upon microwave exposure in the aromatic plant Ocimum basilicum.
abstract: Exposure to sustained low intensity microwaves can constitute a stress for the plants, but its effects on plant secondary chemistry are poorly known. We studied the influence of GSM and WLAN-frequency microwaves on emissions of volatile organic compounds and content of essential oil in the aromatic plant Ocimum basilicum L. hypothesizing that microwave exposure leads to enhanced emissions of stress volatiles and overall greater investment in secondary compounds. Compared to the control plants, microwave irradiation led to decreased emissions of β-pinene, α-phellandrene, bornyl acetate, β-myrcene, α-caryophyllene and benzaldehyde, but increased emissions of eucalyptol, estragole, caryophyllene oxide, and α-bergamotene. The highest increase in emission, 21 times greater compared to control, was observed for caryophyllene oxide. The irradiation resulted in increases in the essential oil content, except for the content of phytol which decreased by 41% in the case of GSM-frequency, and 82% in the case of WLAN-frequency microwave irradiation. The strongest increase in response to WLAN irradiation, >17 times greater, was observed for hexadecane and octane contents. Comparisons of volatile compositions by multivariate analyses demonstrated a clear separation of different irradiance treatments, and according to the changes in the volatile emissions, the WLAN-frequency irradiation represented a more severe stress than the GSM-frequency irradiation. Overall, these results demonstrating important modifications in the emission rates, essential oil content and composition indicate that microwave irradiation influences the quality of herbage of this economically important spice plant.
authors.affiliation: National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, Cluj-Napoca 400293, Romania.
authors.forename: Ildikó
authors.initials: I
authors.lastname: Lung
authors.affiliation: National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, Cluj-Napoca 400293, Romania. Electronic address: loredana.soran@itim-cj.ro.
authors.forename: Maria-Loredana
authors.initials: ML
authors.lastname: Soran
authors.affiliation: National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, Cluj-Napoca 400293, Romania.
authors.forename: Ocsana
authors.initials: O
authors.lastname: Opriş
authors.affiliation: National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, Cluj-Napoca 400293, Romania.
authors.forename: Mihail Radu Cătălin
authors.initials: MRC
authors.lastname: Truşcă
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 1 Kreutzwaldi Street, Tartu 51014, Estonia.
authors.forename: Ülo
authors.initials: Ü
authors.lastname: Niinemets
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 1 Kreutzwaldi Street, Tartu 51014, Estonia; Institute of Technical and Natural Sciences Research-Development of "Aurel Vlaicu" University, 2 Elena Drăgoi Street, Arad 310330, Romania.
authors.forename: Lucian
authors.initials: L
authors.lastname: Copolovici
mesh_terms: D040421:Cell Phone; D008122:Local Area Networks; D008872:Microwaves / Q000009:adverse effects* / Q000145:classification; D018649:Ocimum basilicum / Q000737:chemistry / Q000528:radiation effects*; D009822:Oils, Volatile / Q000378:metabolism* / Q000528:radiation effects; D055549:Volatile Organic Compounds / Q000378:metabolism* / Q000528:radiation effects; D059015:Wireless Technology
chemical_list: D009822:Oils, Volatile; D055549:Volatile Organic Compounds
keywords: Constitutive emissions; Essential oils; Induced emissions; Microwave irradiation; Ocimum basilicum