A highly efficient antioxidative defence system, including both nonenzymatic and enzymatic constituents, is present in plant cells to counteract the toxicity of reactive oxygen species (ROS). Several environmental stresses, such as light excess, exert their effect by producing ROS . Overproduction of ROS causes oxidative damage to cellular components and their involvement in a number of abiotic stresses is well documented (Mittler R., 2002. Oxidative stress: antioxidants and stress tolerance. Trends Plant Sci. 7: 505-410). An antioxidant defence system provides protection against ROS, consisting of enzymes such as superoxide dismutase (SOD) and peroxidase (POD) or metabolites participating in redox reactions like poliphenols and glutathione. We examined the effect of sunlight exposure and water management on two native cultivars of grapevine (Cornalin e Petit rouge) from Aosta Valley. Grape berries were sampled in 2008 and 2009 during two growing seasons (from June to September) before véraison. The fruits sampled differ for: i) exposition to direct solar radiation (SUN); ii) shading from direct solar radiation (SHADE); iii) vineyard exposition (EAST, WEST); iv) water management (IRR, NO IRR). Since some Petit rouge berries showed sunburn on the skin in all ripening condition, not detected in Cornalin, we preliminarily performed the histochemical detection of H2O2 by optical microscopy. The information collected by histochemical analysis evidenced that the H2O2 accumulation occurs in the skin tissue of all symptomatic Petit rouge berries, confirming that modification of antioxidant system occurs in sunburned berries. To investigate the biochemical behaviour underlying the histochemical evidences, we have analyzed the POD activity involved in ROS scavenging. The results relative to 2008-2009 growing years showed the lowest activity in Cornalin. In sunburned berries of Petit rouge we detected the highest POD activity. POD activity increased only in the presence of burn symptoms suggesting its involvement as a consequence of senescence rather than to prevent a possible damage due to excess of solar radiation. The analysis of phenolic compounds in grapes is of considerable importance, since it is known that their contribute to the flavour and colour of wine in addition to an antioxidant role. The content of total poliphenols (mg g -1 F.W.) decreased steadily during the development of fruit in the summer season, probably as a consequence of dilution effect of skin components. Petit rouge SUN NO IRR WEST showed higher content of total poliphenols. A relevant defence system against oxidative stress is represented by glutathione, which protects many cellular components and preserves the thiol status of proteins. Glutathione redox status was determined in berries sampled in 2008 and 2009.

Evaluation of some parameters related to oxidative stress on two native cultivars of grapevine (Cornalin and Petit rouge) from Aosta Valley : effect of canopy exposure and irrigation / S. Donnini, P. De Nisi , M. Dell’Orto, G. Zocchi, O. Zecca. ((Intervento presentato al 17. convegno International Symposium GIESCO 2011 Group of International Experts of Vitivinicultural Systems for Cooperation tenutosi a Asti ; Alba nel 2011.

Evaluation of some parameters related to oxidative stress on two native cultivars of grapevine (Cornalin and Petit rouge) from Aosta Valley : effect of canopy exposure and irrigation

S. Donnini;P. De Nisi;M. Dell’Orto;G. Zocchi;
2011

Abstract

A highly efficient antioxidative defence system, including both nonenzymatic and enzymatic constituents, is present in plant cells to counteract the toxicity of reactive oxygen species (ROS). Several environmental stresses, such as light excess, exert their effect by producing ROS . Overproduction of ROS causes oxidative damage to cellular components and their involvement in a number of abiotic stresses is well documented (Mittler R., 2002. Oxidative stress: antioxidants and stress tolerance. Trends Plant Sci. 7: 505-410). An antioxidant defence system provides protection against ROS, consisting of enzymes such as superoxide dismutase (SOD) and peroxidase (POD) or metabolites participating in redox reactions like poliphenols and glutathione. We examined the effect of sunlight exposure and water management on two native cultivars of grapevine (Cornalin e Petit rouge) from Aosta Valley. Grape berries were sampled in 2008 and 2009 during two growing seasons (from June to September) before véraison. The fruits sampled differ for: i) exposition to direct solar radiation (SUN); ii) shading from direct solar radiation (SHADE); iii) vineyard exposition (EAST, WEST); iv) water management (IRR, NO IRR). Since some Petit rouge berries showed sunburn on the skin in all ripening condition, not detected in Cornalin, we preliminarily performed the histochemical detection of H2O2 by optical microscopy. The information collected by histochemical analysis evidenced that the H2O2 accumulation occurs in the skin tissue of all symptomatic Petit rouge berries, confirming that modification of antioxidant system occurs in sunburned berries. To investigate the biochemical behaviour underlying the histochemical evidences, we have analyzed the POD activity involved in ROS scavenging. The results relative to 2008-2009 growing years showed the lowest activity in Cornalin. In sunburned berries of Petit rouge we detected the highest POD activity. POD activity increased only in the presence of burn symptoms suggesting its involvement as a consequence of senescence rather than to prevent a possible damage due to excess of solar radiation. The analysis of phenolic compounds in grapes is of considerable importance, since it is known that their contribute to the flavour and colour of wine in addition to an antioxidant role. The content of total poliphenols (mg g -1 F.W.) decreased steadily during the development of fruit in the summer season, probably as a consequence of dilution effect of skin components. Petit rouge SUN NO IRR WEST showed higher content of total poliphenols. A relevant defence system against oxidative stress is represented by glutathione, which protects many cellular components and preserves the thiol status of proteins. Glutathione redox status was determined in berries sampled in 2008 and 2009.
Settore AGR/13 - Chimica Agraria
Evaluation of some parameters related to oxidative stress on two native cultivars of grapevine (Cornalin and Petit rouge) from Aosta Valley : effect of canopy exposure and irrigation / S. Donnini, P. De Nisi , M. Dell’Orto, G. Zocchi, O. Zecca. ((Intervento presentato al 17. convegno International Symposium GIESCO 2011 Group of International Experts of Vitivinicultural Systems for Cooperation tenutosi a Asti ; Alba nel 2011.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/191120
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