title: Dualex: a new instrument for field measurements of epidermal ultraviolet absorbance by chlorophyll fluorescence.
abstract: Dualex (dual excitation) is a field-portable instrument, hereby described, for the assessment of polyphenolic compounds in leaves from the measurement of UV absorbance of the leaf epidermis by double excitation of chlorophyll fluorescence. The instrument takes advantage of a feedback loop that equalizes the fluorescence level induced by a reference red light to the UV-light-induced fluorescence level. This allows quick measurement from attached leaves even under field conditions. The use of light-emitting diodes and of a leaf-clip configuration makes Dualex a user-friendly instrument with potential applications in ecophysiological research, light climate analysis, agriculture, forestry, horticulture, pest management, selection of medicinal plants, and wherever accumulation of leaf polyphenolics is involved in plant responses to the environment.
authors.affiliation: Centre National de la Recherche Scientifique, Batiment 203, Centre Universitaire Paris-Sud, BP 34, F91898 Orsay Cedex, France. yves.goulas@lure.u-psud.fr
authors.forename: Yves
authors.initials: Y
authors.lastname: Goulas
authors.forename: Zoran G
authors.initials: ZG
authors.lastname: Cerovic
authors.forename: Aurélie
authors.initials: A
authors.lastname: Cartelat
authors.forename: Ismaël
authors.initials: I
authors.lastname: Moya
mesh_terms: D002734:Chlorophyll / Q000032:analysis / Q000378:metabolism*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005419:Flavonoids / Q000032:analysis / Q000378:metabolism*; D008904:Miniaturization; D010636:Phenols / Q000032:analysis / Q000378:metabolism*; D019441:Plant Epidermis / Q000378:metabolism* / Q000528:radiation effects; D018515:Plant Leaves / Q000378:metabolism* / Q000528:radiation effects; D059808:Polyphenols; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*; D013056:Spectrophotometry, Ultraviolet / Q000295:instrumentation* / Q000379:methods; D014466:Ultraviolet Rays
chemical_list: D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D002734:Chlorophyll