title: Functional, histological and biomechanical characterization of wheat water-mutant leaves.
abstract: A wheat (Triticum turgidum subsp. durum) mutant, generated with sodium azide from wild-type (WT) cv. 'Trinakria', differs in its water affinity of dry leaves, and was designated as a water-mutant. Compared with the WT, water-mutant leaves have lower rates of water uptake, while stomatal and cuticular transpiration do not differ. The nuclear magnetic resonance proton signals used for image reconstruction of leaf cross sections showed differences between these genotypes for the T1 proton spin-density and the T2 proton spin-spin relaxation time. Structural and histochemical analyses at midrib level showed that the water-mutant has thinner leaves, with more and smaller cells per unit area of mesophyll and sclerenchyma, and has altered staining patterns of lignin and pectin-like substances. Stress-strain curves to examine the rheological properties of the leaves showed a biphasic trend, which reveals that the tensile strength at break load and the elastic modulus of the second phase of the water-mutant are significantly higher than for the WT. These data support the proposal of interrelationships among local biophysical properties of the leaf, the microscopic water structure, the rheological properties and the water flux rate across the leaf. This water-mutant can be used for analysis of the genetic basis of these differences, and for identification of gene(s) that govern these traits.
authors.affiliation: Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per la Cerealicoltura S.S. 673 Km 25,200, 71122 Foggia, Italy.
authors.forename: Agata
authors.initials: A
authors.lastname: Rascio
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, viale Colombo 3, 35121 Padova, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Rascio
authors.affiliation: Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per la Cerealicoltura S.S. 673 Km 25,200, 71122 Foggia, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Rinaldi
authors.affiliation: Consiglio per la Ricerca e la Sperimentazione in Agricoltura - Centro di Ricerca per la Nutrizione e gli Alimenti, Via Ardeatina 546, 00178 Rome, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Valentini
mesh_terms: D001692:Biological Transport; D005838:Genotype; D008279:Magnetic Resonance Imaging; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000502:physiology; D054046:Plant Stomata / Q000166:cytology / Q000235:genetics / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology; D014908:Triticum / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D014867:Water / Q000378:metabolism*
chemical_list: D014867:Water