title: Pollen Morphology and Boron Concentration in Floral Tissues as Factors Triggering Natural and GA-Induced Parthenocarpic Fruit Development in Grapevine.
abstract: Parthenocarpic fruit development (PFD) reduces fruit yield and quality in grapevine. Parthenocarpic seedless berries arise from fruit set without effective fertilization due to defective pollen germination. PFD has been associated to micronutrient deficiency but the relation of this phenomenon with pollen polymorphism has not been reported before. In this work, six grapevine cultivars with different tendency for PFD and grown under micronutrient-sufficient conditions were analyzed to determine pollen structure and germination capability as well as PFD rates. Wide variation in non-germinative abnormal pollen was detected either among cultivars as well as for the same cultivar in different growing seasons. A straight correlation with PFD rates was found (R2 = 0.9896), suggesting that natural parthenocarpy is related to defective pollen development. Such relation was not observed when PFD was analyzed in grapevine plants exposed to exogenous gibberellin (GA) or abscissic acid (ABA) applications at pre-anthesis. Increase (GA treatment) or reduction (ABA treatment) in PFD rates without significative changes in abnormal pollen was determined. Although these plants were maintained at sufficient boron (B) condition, a down-regulation of the floral genes VvBOR3 and VvBOR4 together with a reduction of floral B content in GA-treated plants was established. These results suggest that impairment in B mobility to reproductive tissues and restriction of pollen tube growth could be involved in the GA-induced parthenocarpy.
authors.affiliation: Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile.
authors.forename: Orlando
authors.initials: O
authors.lastname: Alva
authors.affiliation: Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile.
authors.forename: Rosa Nair
authors.initials: RN
authors.lastname: Roa-Roco
authors.affiliation: Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Pérez-Díaz
authors.affiliation: Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile.
authors.forename: Mónica
authors.initials: M
authors.lastname: Yáñez
authors.affiliation: Instituto de Química de Recursos naturales, Universidad de Talca, Talca, Chile.
authors.forename: Jaime
authors.initials: J
authors.lastname: Tapia
authors.affiliation: Centro Tecnológico de la Vid y el Vino, Facultad de Ciencias Agrarias, Universidad de Talca, Talca, Chile.
authors.forename: Yerko
authors.initials: Y
authors.lastname: Moreno
authors.affiliation: Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile.
authors.forename: Simón
authors.initials: S
authors.lastname: Ruiz-Lara
authors.affiliation: Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile.
authors.forename: Enrique
authors.initials: E
authors.lastname: González
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D001895:Boron / Q000378:metabolism*; D035264:Flowers / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D005638:Fruit / Q000187:drug effects / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000494:pharmacology; D010312:Parthenogenesis / Q000187:drug effects / Q000235:genetics; D011058:Pollen / Q000033:anatomy & histology*; D054817:Pollination / Q000235:genetics*; D027843:Vitis / Q000033:anatomy & histology* / Q000235:genetics / Q000378:metabolism
chemical_list: D005875:Gibberellins; D000040:Abscisic Acid; D001895:Boron