title: The Evolution of Total Phenolic Compounds and Antioxidant Activities during Ripening of Grapes (Vitis vinifera L., cv. Tempranillo) Grown in Semiarid Region: Effects of Cluster Thinning and Water Deficit.
abstract: A study was made of how water status (rainfed vs. irrigated) and crop load (no cluster thinning vs. cluster thinning) can together affect the grapes ofVitis viniferacv. Tempranillo vines growing in a semiarid zone of Extremadura (Spain). The grapes were monitored at different stages of ripening, measuring the peroxidase (POX) and superoxide dismutase (SOD) antioxidant activities and the phenolic content (flavonoids and phenylpropanoids), together with other parameters. The irrigation regime was adjusted to provide 100% of crop evapotranspiration (ETc). The findings confirmed previous results that both thinning and water deficit advance ripening, while irrigation and high crop load (no thinning) lengthen the growth cycle. The SOD activity remained practically constant throughout ripening in the thinned treatments and was always lower than in the unthinned treatments, an aspect which could have been the cause of the observed greater level of lipid peroxidation in the water deficit, thinned treatment. The nonspecific peroxidase activity was very low, especially in the thinned treatments. The effect of thinning was enhanced when combined with water deficit, inducing increases in phenylpropanoids and, above all, flavonoids at the harvest stage of ripening, while leaving the polyphenol oxidase activity (PPO) unaffected.
authors.affiliation: Department of Plant Biology, Ecology and Earth Sciences, University of Extremadura, 06006 Badajoz, Spain. igarridoc@unex.es.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Garrido
authors.affiliation: CICYTEX-Institute of Agricultural Research Finca La Orden-Valdesequera, Ctra. A-V, Km 372, 06187 Badajoz, Spain. david.uriarte@gobex.es.
authors.forename: David
authors.initials: D
authors.lastname: Uriarte
authors.affiliation: Aula Dei Scientific Technological Park Foundation, Av. Montañana 930, 50059 Zaragoza, Spain. marcoshsuarez@gmail.com.
authors.forename: Marcos
authors.initials: M
authors.lastname: Hernández
authors.affiliation: Department of Plant Biology, Ecology and Earth Sciences, University of Extremadura, 06006 Badajoz, Spain. jllerena@ctaex.com.|Agri-Food Technological Center of Extremadura-CTAEX, 06195 Badajoz, Spain. jllerena@ctaex.com.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Llerena
authors.affiliation: CICYTEX-Technological Institute of Food and Agriculture-INTAEX, Av. Adolfo Suárez s/n, 06071 Badajoz, Spain. esperanza.valdes@gobex.es.
authors.forename: María Esperanza
authors.initials: ME
authors.lastname: Valdés
authors.affiliation: Department of Plant Biology, Ecology and Earth Sciences, University of Extremadura, 06006 Badajoz, Spain. espinosa@unex.es.
authors.forename: Francisco
authors.initials: F
authors.lastname: Espinosa
mesh_terms: D057914:Agricultural Irrigation; D000975:Antioxidants / Q000378:metabolism*; D003681:Dehydration; D005419:Flavonoids / Q000378:metabolism; D005638:Fruit / Q000254:growth & development / Q000378:metabolism*; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D009195:Peroxidase / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D027843:Vitis / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010940:Plant Proteins; D009195:Peroxidase; D013482:Superoxide Dismutase
keywords: Vitis vinifera; antioxidant activities; irrigation; phenols; thinning