title: Physiological parameters and protective energy dissipation mechanisms expressed in the leaves of two Vitis vinifera L. genotypes under multiple summer stresses.
abstract: Photosynthetic performances and energy dissipation mechanisms were evaluated on the anisohydric cv. Sangiovese and on the isohydric cv. Montepulciano (Vitis vinifera L.) under conditions of multiple summer stresses. Potted vines of both cultivars were maintained at 90% and 40% of maximum water availability from fruit-set to veraison. One week before veraison, at predawn and midday, main gas-exchange and chlorophyll fluorescence parameters, chlorophyll content, xanthophyll pool and cycle and catalase activity were evaluated. Under water deficit and elevated irradiance and temperature, contrary to cv. Montepulciano and despite a significant leaf water potential decrease, Sangiovese's leaves kept their stomata more open and continued to assimilate CO2 while also showing higher water use efficiency. Under these environmental conditions, in comparison with the isohydric cv. Montepulciano, the protective mechanisms of energy dissipation exerted by the anisohydric cv. Sangiovese were: (i) higher stomatal conductance and thermoregulation linked to higher transpiration rate; (ii) greater ability at dissipating more efficiently the excess energy via the xanthophylls cycle activity (thermal dissipation) due to higher VAZ pool and greater increase of de-epoxidation activity.
authors: Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università di Perugia, Borgo XX Giugno 74, 06128 Perugia, Italy. Electronic address: alberto.palliotti@unipg.it.
authors: Alberto
authors: A
authors: Palliotti
authors: Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università di Perugia, Borgo XX Giugno 74, 06128 Perugia, Italy.
authors: Sergio
authors: S
authors: Tombesi
authors: Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università di Perugia, Borgo XX Giugno 74, 06128 Perugia, Italy.
authors: Tommaso
authors: T
authors: Frioni
authors: Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Via delle Brecce Bianche, 60131 Ancona, Italy.
authors: Oriana
authors: O
authors: Silvestroni
authors: Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Via delle Brecce Bianche, 60131 Ancona, Italy.
authors: Vania
authors: V
authors: Lanari
authors: Dipartimento di Scienze Agrarie, Alimentari ed Agro-Ambientali, Università di Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
authors: Claudio
authors: C
authors: D'Onofrio
authors: Dipartimento di Scienze Agrarie, Alimentari ed Agro-Ambientali, Università di Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
authors: Fabiola
authors: F
authors: Matarese
authors: Dipartimento per l'Innovazione dei Sistemi Biologici, Agroalimentari e Forestali, Università della Tuscia, Via S. Camillo de Lellis, Viterbo, Italy.
authors: Andrea
authors: A
authors: Bellincontro
authors: Dipartimento di Scienze delle Produzioni Vegetali Sostenibili, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29100 Piacenza, Italy.
authors: Stefano
authors: S
authors: Poni
mesh_terms: D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D005838:Genotype; D006358:Hot Temperature / Q000009:adverse effects*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008027:Light / Q000009:adverse effects*; D018384:Oxidative Stress; D010788:Photosynthesis; D018515:Plant Leaves / Q000502:physiology*; D013312:Stress, Physiological; D027843:Vitis / Q000235:genetics / Q000502:physiology*; D014867:Water / Q000494:pharmacology*; D024341:Xanthophylls / Q000378:metabolism
chemical_list: D024341:Xanthophylls; D014867:Water; D002734:Chlorophyll; D006861:Hydrogen Peroxide; D002374:Catalase
keywords: Catalase activity; Chlorophyll fluorescence; Grapevine; Multiple summer stresses; Photosynthesis; Xanthophylls