title: Herbicide isoproturon-specific binding in the freshwater macrophyte Elodea densa--a single-cell fluorescence study.
abstract: The experimental approach to the effects of the phenylurea herbicide Isoproturon (IPU), on the photosynthesis activity of leaf cells of the freshwater macrophyte Elodea densa was based on the fast induction kinetics of the PSII chlorophyll a in vivo fluorescence. FI/FP ratios determined on the induction curves exhibited a noticeable effect at 5 micrograms IPU.liter-1. They appeared to be the most reliable parameter for the quantitative evaluation of the dissociation constant of the complex "IPU/D1 protein" (Kd = 1.2 x 10(-7) M) and of the concentration of free IPU either at the thylakoid level or in the surrounding medium of the leaf epithelial cells. Total IPU bioaccumulation at the whole plant level as a function of [IPU] in the medium indicated that the D1 protein represented the main binding site for IPU in this aquatic plant species.
authors.affiliation: Centre de Recherche Paul Pascal, CNRS, Pessac, France.
authors.forename: M
authors.initials: M
authors.lastname: Grouselle
authors.forename: T
authors.initials: T
authors.lastname: Grollier
authors.forename: A
authors.initials: A
authors.lastname: Feurtet-Mazel
authors.forename: F
authors.initials: F
authors.lastname: Ribeyre
authors.forename: A
authors.initials: A
authors.lastname: Boudou
mesh_terms: D001665:Binding Sites; D002734:Chlorophyll / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005618:Fresh Water / Q000737:chemistry*; D006540:Herbicides / Q000378:metabolism* / Q000633:toxicity; D045342:Light-Harvesting Protein Complexes; D008782:Methylurea Compounds / Q000378:metabolism* / Q000633:toxicity; D008962:Models, Theoretical; D010671:Phenylurea Compounds; D010788:Photosynthesis / Q000187:drug effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism; D045332:Photosystem II Protein Complex; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity
chemical_list: D006540:Herbicides; D045342:Light-Harvesting Protein Complexes; D008782:Methylurea Compounds; D010671:Phenylurea Compounds; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D014874:Water Pollutants, Chemical; D002734:Chlorophyll; C028904:isoproturon