title: Effect of chromium species on phytochemical and physiological parameters in Datura innoxia.
abstract: In soil, chromium can be found in two main valence states: hexavalent Cr(VI) and trivalent Cr(III). In this study, we investigated the impact of Cr on photosynthetic gas exchange, photosystem II (PSII) activity, Cr translocation and accumulation, proline content and alkaloids production, i.e. scopolamine and hyoscyamine, in Datura innoxia. Cr uptake was influenced by its oxidation state and its concentration in growth medium. The plant roots were determined as being the main organ of Cr accumulation. Cr(VI) was more toxic than Cr(III) as indicated by reduction in plant biomass and net photosynthesis. The stomatal conductance showed a similar trend to that of photosynthetic capacity. Cr(III) and Cr(VI) had a different impact on substomatal CO(2) concentration then Cr toxicity was related to its oxidation states. In plants stressed with a Cr(VI) excess, a down regulation of PSII activity was observed with an impairment of photochemical activity. Indeed, the maximum quantum yield of PSII (F(v)/F(m)), the quantum yield of PSII (PhiPSII) and the efficiency of excitation capture by open centers (F'(v)/F'(m)) decreased. Cr(III) had little effects on PSII primary photochemistry, whatever its form induces an increase of scopolamine content without changes in hyoscyamine content in leaves of D. innoxia. These results provide that chromium contamination can change the secondary metabolites composition of leaves, thereby, impacting the quality, safety and efficacy of natural plant products synthesized by D. innoxia plants.
authors.affiliation: Laboratoire de Physiologie et Biotechnologies Végétales (UPBV EA 3296), Université Blaise Pascal/IUT de l'Université d'Auvergne, IUT de Clermont-Ferrand, Aurillac, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Vernay
authors.forename: Cécile
authors.initials: C
authors.lastname: Gauthier-Moussard
authors.forename: Liliane
authors.initials: L
authors.lastname: Jean
authors.forename: François
authors.initials: F
authors.lastname: Bordas
authors.forename: Olivier
authors.initials: O
authors.lastname: Faure
authors.forename: Gérard
authors.initials: G
authors.lastname: Ledoigt
authors.forename: Adnane
authors.initials: A
authors.lastname: Hitmi
mesh_terms: D000470:Alkaloids / Q000096:biosynthesis; D002849:Chromatography, Gas; D017608:Chromium Compounds / Q000633:toxicity*; D032302:Datura / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D004579:Electron Transport / Q000502:physiology; D007700:Kinetics; D009747:Nutritional Physiological Phenomena; D010788:Photosynthesis / Q000187:drug effects; D018526:Plant Transpiration / Q000187:drug effects / Q000502:physiology; D011392:Proline / Q000032:analysis / Q000378:metabolism
chemical_list: D000470:Alkaloids; D017608:Chromium Compounds; D011392:Proline