title: Detection of herbicide effects on pigment composition and PSII photochemistry in Helianthus annuus by Raman spectroscopy and chlorophyll a fluorescence.
abstract: The effects of herbicides from three mode-of-action groups - inhibitors of protoporphyrinogen oxidase (carfentrazone-ethyl), inhibitors of carotenoid biosynthesis (mesotrione, clomazone, and diflufenican), and inhibitors of acetolactate synthase (amidosulfuron) - were studied in sunflower plants (Helianthus annuus). Raman spectroscopy, chlorophyll fluorescence (ChlF) imaging, and UV screening of ChlF were combined to evaluate changes in pigment composition, photosystem II (PSII) photochemistry, and non-photochemical quenching in plant leaves 6d after herbicide application. The Raman signals of phenolic compounds, carotenoids, and chlorophyll were evaluated and differences in their intensity ratios were observed. Strongly augmented relative content of phenolic compounds was observed in the case of amidosulfuron-treated plants, with a simultaneous decrease in the chlorophyll/carotenoid intensity ratio. The results were confirmed by in vivo measurement of flavonols using UV screening of ChlF. Herbicides from the group of carotenoid biosynthesis inhibitors significantly decreased both the maximum quantum efficiency of PSII and non-photochemical quenching as determined by ChlF. Resonance Raman imaging (mapping) data with high resolution (150,000-200,000 spectra) are presented, showing the distribution of carotenoids in H. annuus leaves treated by two of the herbicides acting as inhibitors of carotenoid biosynthesis (clomazone or diflufenican). Clear signs were observed that the treatment induced carotenoid depletion within sunflower leaves. The depletion spatial pattern registered differed depending on the type of herbicide applied.
authors.affiliation: Global Change Research Institute CAS, v.v.i., Bělidla 4a, 603 00 Brno, Czech Republic. Electronic address: vitek.p@czechglobe.cz.
authors.forename: Petr
authors.initials: P
authors.lastname: Vítek
authors.affiliation: Global Change Research Institute CAS, v.v.i., Bělidla 4a, 603 00 Brno, Czech Republic. Electronic address: novotna.k@czechglobe.cz.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Novotná
authors.affiliation: Global Change Research Institute CAS, v.v.i., Bělidla 4a, 603 00 Brno, Czech Republic. Electronic address: rajsnerova.p@czechglobe.cz.
authors.forename: Petra
authors.initials: P
authors.lastname: Hodaňová
authors.affiliation: Global Change Research Institute CAS, v.v.i., Bělidla 4a, 603 00 Brno, Czech Republic. Electronic address: rapantova.b@czechglobe.cz.
authors.forename: Barbora
authors.initials: B
authors.lastname: Rapantová
authors.affiliation: Global Change Research Institute CAS, v.v.i., Bělidla 4a, 603 00 Brno, Czech Republic. Electronic address: klem.k@czechglobe.cz.
authors.forename: Karel
authors.initials: K
authors.lastname: Klem
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D044948:Flavonols / Q000032:analysis; D005453:Fluorescence; D006368:Helianthus / Q000737:chemistry* / Q000187:drug effects; D006540:Herbicides / Q000633:toxicity*; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D019441:Plant Epidermis / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry; D012015:Reference Standards; D013059:Spectrum Analysis, Raman
chemical_list: D044948:Flavonols; D006540:Herbicides; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D000077194:Chlorophyll A
keywords: Carotenoids; Chlorophyll fluorescence; Flavonoids; Photosynthesis; Raman mapping; Secondary metabolites