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Dinis L.-T.,University of Tras os Montes e Alto Douro | Oliveira M.M.,University of Tras os Montes e Alto Douro | Almeida J.,University of Tras os Montes e Alto Douro | Costa R.,National Institute of Biological Resources L INIA | And 2 more authors.
Food Chemistry

The antioxidant properties of different ecotypes of chestnut nut (cv. Judia) were studied. Total phenolics and flavonoids were also determinated. Total phenolics amount ranged from 9.6 mg/g of GAE (hottest ecotype, Mura) to 19.4 mg/g of GAE (coldest ecotype, Valpaos). Gallic and ellagic acid were the predominant compounds and Valpaos had the highest values while, Mura had the lowest ones. The antioxidant capacity of ethanolic extracts were evaluated through several biochemical essays: ABTS (2,2′-azinobis-(3- ethylbenzothiazoline-6-sulphonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging activity, FRAP (ferric reducing/antioxidant power) and inhibition of oxidative haemolysis in erythrocytes. In order to evaluate the antioxidant efficiency of each ecotype, the EC 50 values were calculated. Once again Valpaos revealed the best antioxidant properties, presenting much lower EC 50 values. Climatic conditions influence seems to be a limiting factor for production of phenolic compounds and consequently for the antioxidant properties of chestnut nuts. © 2011 Elsevier Ltd. All rights reserved. Source

Dinis L.-T.,University of Tras os Montes e Alto Douro | Peixoto F.,University of Tras os Montes e Alto Douro | Zhang C.,University of Tras os Montes e Alto Douro | Martins L.,University of Tras os Montes e Alto Douro | And 2 more authors.
Physiological and Molecular Plant Pathology

Different changes in physiological and biochemical parameters were observed between resistant and sensitive chestnut plantlets upon inoculation with the ink disease pathogen Phytophthora cinnamomi. Infection led to shoot death in 87.5% of the sensitive plants (cv. Judia) in 30 days, while all resistant plants (Ca90, hybrid C. crenata× C sativa progeny) survived. Judia plants exhibited a decrease of 92.9% in leaf water potential 16 days after infection, while in Ca90 plants the decrease was only 35.8%. After infection, the photosynthetic rate of Judia plants decreased significantly by 58.3%. A significant increase in the level of total phenols (50%) was observed in the leaves in infected Ca90 plants; whereas in sensitive Judia plants, no difference in phenol content was observed upon the oomycete infection. Infection also resulted in an increase in soluble sugars and a decrease in starch content in the resistant genotype. These results provided new insights into the mechanisms of resistance to chestnut ink disease. © 2011 Elsevier Ltd. Source

Dinis L.T.,University of Tras os Montes e Alto Douro | Peixoto F.,University of Tras os Montes e Alto Douro | Pinto T.,National Institute of Biological Resources L INIA | Costa R.,National Institute of Biological Resources L INIA | And 2 more authors.
Environmental and Experimental Botany

Morphological and histological adaptation of chestnut leaves at the different altitudes and edaphoclimate conditions were shown. The study was carried out on Castanea sativa Mill. var. 'Judia'. The growth range altitudes of 'Judia' were between 709ma.s.l. and 860ma.s.l. (above sea level), corresponding to a variation in the sum of temperatures (expressed in degree-day values - °D) of 2751°D to 2316°D in 2006 and 2338°D to 1700°D in 2007, between May and October. In 2007 the thickest leaves (319.9μm), the highest stomata density (469.1 stomata mm-2), one of the largest leaf areas (69.2cm2) and the highest fruit size (71.7 fruit kg-1) were observed in Alfândega da Fé (759ma.s.l., 2186°D, during the May-October period) whereas in 2006 the highest fruit size (86.8 fruit kg-1) was observed in Valpaços (860ma.s.l., 2316°D, during the same period).Additionally, the leaves of the trees grown in this locality (Valpaços) displayed one of the largest areas (57.0cm2). Overall results suggest that annual climate conditions do significantly influence both fruit and leaf biometric characteristics, and that the range of temperatures from 2100°D to 2300°D (between May and October) correspond to the optimal temperature sum, which can be ascribed to different places, depending on the year in question. Concerning the molecular characterisation using nuclear microsatellites, the individuals more distant are those from Macedo de Cavaleiros and Alfândega da Fé (genetic distance=0.227), while the ecotypes with closer similarities were those collected in Murça and Vinhais (genetic identity=1.171). The current results suggest that the morphological and phenological differences among ecotypes are not related to the small genetic differences, but are simply phenotypic adaptations to diffent climatic conditions. © 2010 Elsevier B.V. Source

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