The antioxidant metabolism of higher plants undergoes alterations according to a seasonal cycle. Studies have demonstrated that free radicals are formed in dormant buds, where their removal seems to be associated with bud break. Protection against free oxygen radicals is achieved through the action of antioxidant compounds and enzymes. In flower buds of two apricot cultivars with different chilling requirement, changes in antioxidant enzymes (catalase, peroxidase, ascorbate peroxidase), sulfhydryl compounds and glutathione content during the winter season were determined. In both cultivars, the activities of oxygen-scavenging enzymes and glutathione underwent change during the winter season. During deep dormancy such activities were low, subsequently increasing but reaching different levels between cultivars. Increases were particularly high in the cultivar with low chilling requirement, and occurred in concomitance with the end of endo-dormancy. Lowest antioxidant activity was detected in the cultivar with high chilling requirement. These results suggest that minimum thresholds in antioxidant activities could be crucial for scavenging free radicals generated during the winter season.
Changes in antioxidant compounds in flower buds of two apricot cultivars during in winter season
VITI, RAFFAELLA
2006-01-01
Abstract
The antioxidant metabolism of higher plants undergoes alterations according to a seasonal cycle. Studies have demonstrated that free radicals are formed in dormant buds, where their removal seems to be associated with bud break. Protection against free oxygen radicals is achieved through the action of antioxidant compounds and enzymes. In flower buds of two apricot cultivars with different chilling requirement, changes in antioxidant enzymes (catalase, peroxidase, ascorbate peroxidase), sulfhydryl compounds and glutathione content during the winter season were determined. In both cultivars, the activities of oxygen-scavenging enzymes and glutathione underwent change during the winter season. During deep dormancy such activities were low, subsequently increasing but reaching different levels between cultivars. Increases were particularly high in the cultivar with low chilling requirement, and occurred in concomitance with the end of endo-dormancy. Lowest antioxidant activity was detected in the cultivar with high chilling requirement. These results suggest that minimum thresholds in antioxidant activities could be crucial for scavenging free radicals generated during the winter season.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
