title: Non-destructive optical monitoring of grape maturation by proximal sensing.
abstract: A new, commercial, fluorescence-based optical sensor for plant constituent assessment was recently introduced. This sensor, called the Multiplex(®) (FORCE-A, Orsay, France), was used to monitor grape maturation by specifically monitoring anthocyanin accumulation. We derived the empirical anthocyanin content calibration curves for Champagne red grape cultivars, and we also propose a general model for the influence of the proportion of red berries, skin anthocyanin content and berry size on Multiplex(®) indices. The Multiplex(®) was used on both berry samples in the laboratory and on intact clusters in the vineyard. We found that the inverted and log-transformed far-red fluorescence signal called the FERARI index, although sensitive to sample size and distance, is potentially the most widely applicable. The more robust indices, based on chlorophyll fluorescence excitation ratios, showed three ranges of dependence on anthocyanin content. We found that up to 0.16 mg cm(-2), equivalent to approximately 0.6 mg g(-1), all indices increase with accumulation of skin anthocyanin content. Excitation ratio-based indices decrease with anthocyanin accumulation beyond 0.27 mg cm(-2). We showed that the Multiplex(®) can be advantageously used in vineyards on intact clusters for the non-destructive assessment of anthocyanin content of vine blocks and can now be tested on other fruits and vegetables based on the same model.
authors.affiliation: CNRS, Laboratoire Écologie, Systématique et Évolution, UMR 8079, Bât 362, Orsay, Université Paris-Sud, Orsay, AgroParisTech, Paris F-75231, France. naima.ghozlen@u-psud.fr
authors.forename: Naïma
authors.initials: N
authors.lastname: Ben Ghozlen
authors.forename: Zoran G
authors.initials: ZG
authors.lastname: Cerovic
authors.forename: Claire
authors.initials: C
authors.lastname: Germain
authors.forename: Sandrine
authors.initials: S
authors.lastname: Toutain
authors.forename: Gwendal
authors.initials: G
authors.lastname: Latouche
mesh_terms: D000872:Anthocyanins / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D002734:Chlorophyll / Q000737:chemistry; D005638:Fruit / Q000737:chemistry*; D055096:Optical Devices; D027843:Vitis / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D002734:Chlorophyll