title: MRI investigation of subcellular water compartmentalization and gas distribution in apples.
abstract: Water status and distribution at subcellular level in whole apple fruit were evaluated by Magnetic Resonance Imaging (MRI) measurement of the multi-exponential transverse (T2) relaxation of water protons. Apparent microporosity, also estimated by MRI, provided mapping of gas distribution in fruit tissues. Measuring for the first time the multi-exponential relaxation of water and apparent tissue microporosity in whole fruit and combining these with histological measurements provided a more reliable interpretation of the origins of variations in the transverse relaxation time (T2) and better characterization of the fruit tissue. Measurements were performed on 54 fruits from 3 different cultivars. Fruits of different sizes were selected for each cultivar to provide tissues with cells of different dimensions. Macrovision measurements were carried out on parenchymal tissue from all fruits to investigate the impact of cell size on T2 value. The results showed that the MRI transverse relaxation signal is well fitted by a tri-exponential decay curve that reflects cell compartmentalization. Variations in cell size partially explained the different T2 observed. This study highlighted the heterogeneity of apple tissues in terms of relaxation parameters, apparent microporosity and cell morphology and in relation to specific variations between fruit of different cultivars.
authors.affiliation: Irstea, UR TERE, 17 Avenue de Cucillé, CS 64427, F-35044 Rennes, France; INRA, UR1268 BIA, rue de la Géraudière, BP 71627, F-44316 Nantes, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Winisdorffer
authors.affiliation: Irstea, UR TERE, 17 Avenue de Cucillé, CS 64427, F-35044 Rennes, France. Electronic address: maja.musse@irstea.fr.
authors.forename: Maja
authors.initials: M
authors.lastname: Musse
authors.affiliation: Irstea, UR TERE, 17 Avenue de Cucillé, CS 64427, F-35044 Rennes, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Quellec
authors.affiliation: INRA, UR1268 BIA, rue de la Géraudière, BP 71627, F-44316 Nantes, France.
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Devaux
authors.affiliation: INRA, UR1268 BIA, rue de la Géraudière, BP 71627, F-44316 Nantes, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Lahaye
authors.affiliation: Irstea, UR TERE, 17 Avenue de Cucillé, CS 64427, F-35044 Rennes, France.
authors.forename: François
authors.initials: F
authors.lastname: Mariette
mesh_terms: D005740:Gases; D008279:Magnetic Resonance Imaging; D027845:Malus / Q000737:chemistry*; D014867:Water
chemical_list: D005740:Gases; D014867:Water
keywords: Apple parenchyma tissue; Macrovision; Microporosity; Multi-exponential transverse (T2) relaxation