title: Gating in grapevine: relationship between application of the fungicide fludioxonil and circadian rhythm on photosynthesis.
abstract: The aim of this study was to determine the impact of the fludioxonil (fdx) fungicide on the diurnal fluctuation in grapevine photosynthesis. Therefore, fdx treatment was performed at the end of flowering, at 8 am, 12 am or 7 pm. The study was performed in experimental field and several photosynthesis parameters were followed one day after treatment. Morning fdx treatment induced (i) a significant and simultaneous drop of both photosynthesis (Pn) and stomatal conductance between 8 am and 4 pm and (ii) an increase of intercellular CO(2) concentration when compared to control plants. On the contrary, evening fdx treatment did not affect Pn whereas midday treatment caused Pn increase after 4 pm. These data suggest that (i) morning fdx treatment results in a non-stomatal limitation of Pn, (ii) midday treatment is more suitable to treat grapevine with fdx and (iii) a phenomenon of gating was noticed.
authors.affiliation: Laboratoire de Stress, Défenses et Reproduction des Plantes, URVVC-SE EA 2069, Université de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, F-51687 Reims Cedex 2, France. petit081@etudiant.univ-reims.fr
authors.forename: Anne-Noëlle
authors.initials: AN
authors.lastname: Petit
authors.forename: Florence
authors.initials: F
authors.lastname: Fontaine
authors.forename: Christophe
authors.initials: C
authors.lastname: Clement
authors.forename: Nathalie
authors.initials: N
authors.lastname: Vaillant-Gaveau
mesh_terms: D000383:Agriculture; D015415:Biomarkers / Q000032:analysis; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism; D002940:Circadian Rhythm; D004149:Dioxoles / Q000009:adverse effects*; D005659:Fungicides, Industrial / Q000009:adverse effects*; D010788:Photosynthesis / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D011758:Pyrroles / Q000009:adverse effects*; D027843:Vitis / Q000187:drug effects / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D004149:Dioxoles; D005659:Fungicides, Industrial; D011758:Pyrroles; D002245:Carbon Dioxide; C108339:fludioxonil