Changes in antioxidant compounds in flower buds of two apricot cultivars during in winter season

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

Apricot cultivars and cold storage affect the total antioxidant capacity and glutathione content in fruit

Fresh vegetables and fruits contain a significant amount of biologically-active components that prevent the formation or reduce the level of free radicals in the body. The aim of this research was to evaluate the Total Antioxidant Capacity (TAC) and the glutathione content in apricot fruits (Prunus armeniaea L.), for different maturing stages and cold-storage times. Three apricot cultivars were tested at different maturity times: 'San Castrese', 'Farmingdale', and 'Rapareddu'. The cultivars showed differences in TAC and glutathione levels, related to fruit developmental stage and cold-storage time

The cold hardiness of flower buds in two apricot cultivars

Flower buds are the most frost-sensitive parts of the trees in the cold season, in relation to their phenological and histological stage. For a protective effect, plants activate mechanisms involving many enzymes and antioxidative compounds. In particular, glutathione, the most predominant of the sulfhydryl compounds present in living cells, is involved in many metabolic detoxification processes, that avoid cold stress damage. The purpose of this research was to evaluate the cold hardiness of flower buds at different phenological stages and the changes in sulfhydryl compounds in two Italian apricot cultivars. The two cultivars showed a different susceptibility to cold stress as a function of flower bud phenological stage