S. Bartolini

Anatomical and morphological study of apple (Malus x domestica Borkh.) flower buds growing under inadequate winter chilling

Summary Some apples cultivars produce low yields when grown in regions with inadequate winter chilling. Their unsatisfactory development is attributed to the lack of climatic adaptation which causes some abnormalities in bud differentiation. The development of reproductive spurs is erratic, leading to vegetative shoots, and the flower index is very low. The purpose of this work is to understand the flower differentiation problem. An assessment was made through morphological and histological studies, also an analysis of climatic data was performed in an attempt to identify the responsible factors. The number of chilling hours recorded was about 695. Defoliation was delayed and happened during the second week of January. Bud break was advanced by 10 d in comparison with the average period. The spurs density (12 and 23 spurs per m of twigs) was similar to the values observed in normal situation. The buds carried by these spurs evolved into vegetative shoots for all variety × rootstock combination used in this study. The average of this transformation was 47 and 50% for ‘Golden Delicious’ and ‘Starking Delicious’, respectively. A flowering index obtained was very low (1.3 kg per tree). Anatomical observations carried out on buds collected in October showed that differentiation was undertaken and the floral primordium was already formed with some abnormalities in flower development in later stage. At anthesis, internal structures of the buds showed primordia disorganized. Reproductive organs presented pistil abortion with low microsporogenesis. Xylem vessel elements were not observed at the base of the bud and vascular connection was not established. This problem in flower development occurred at this stage which was affected by external factors. The winter was characterized by periods of high temperatures which affect negatively the accumulation of chilling units. The mode of action of temperature, notably of chilling on the formation of flowering organs and vessels, remains to be determined.

Pomological and Nutraceutical Properties in Apricot Fruit: Cultivation Systems and Cold Storage Fruit Management

We have investigated the effect of cultivation systems and fruit post-harvest management on the antioxidant properties of apricot fruits. Trees of five cultivars ‘Tyrinthos’, ‘Cafona’, ‘Bella d’Italia’, ‘Vitillo’ and ‘Pellecchiella’ were cultivated under integrated and organic systems. Fruits were collected at full maturity stage and analyzed either immediately or after storage at 4±0.5 °C and 85% of relative humidity for seven and 14 days. The main pomological traits (weight, colour, flesh firmness, total soluble sugars, titratable acidity) and antioxidant properties were analyzed. The total antioxidant capacity (TAC by TEAC method), total phenols content (TP by Folin-Ciocalteu method) and carotenoid content by HPLC-DAD were monitored. Cultivar characterization by principal component analysis (PCA) indicated a large variability on pomological and antioxidant properties of apricot fruits. ‘Bella d’Italia’ showed better TAC and TP values compared to the other cultivars. ANOVA interactions between cultivar and cultivation system (organic/integrated) were found for the antioxidant properties. These interactions may help to select a set of genotypes with better performances under organic system, which in our study might be indicated in ‘Cafona’ and ‘Bella d’Italia’.

Genotype, harvest season and cold storage influence on fruit quality and antioxidant properties of apricot

The total antioxidant capacity, total phenols, and selected pomological traits of fresh apricots belonging to 12 genotypes were investigated over a 3-year period. These analyses were carried out on apricots at the ready-to-eat stage and after 7 and 14 days at 4°C cold storage. Total antioxidant capacity and total phenols ranged from 1.14 ± 0.10 μmolTE gFW−1 to 9.93 ± 0.73 μmolTE gFW−1 and from 0.22 ± 0.01 mgGAE gFW−1 to 1.37 ± 0.11 mgGAE gFW−1, respectively. An effect of the harvest year on the antioxidant properties was also found to be dependent on the cultivars. The most storage-susceptible parameter was the flesh firmness of fruits, while the antioxidant level was maintained during storage. The influence of the genotype on fruit quality, which involves pomological and nutraceutical properties, was highlighted by analysis of variance, hierarchical clustering, and principal component analysis.

Total Antioxidant Capacity and Phenolics Content in Apricot Fruits

ABSTRACT Food quality analysis that addresses the nutraceutical profile of produce is fast becoming an accepted profile, primarily highlighting the antioxidant capacity as a further quality index for many fruit and vegetables species. In this study the total antioxidant status of several apricot cultivars differing in ripening season, pomological traits and geographical origin was determined by Trolox Equivalent Antioxidant Capacity (TEAC) assay and total phenol content by Folin-Ciocalteu (F-C) method. Among the cultivars analysed, the variability on the antioxidant capacity and total phenol content was consistent, showing an increasing amount of antioxidants in the late ripening genotypes. These genotypes exhibited the best combination of pomological and nutraceutical traits with an excellent fruit qualitative profile.

The effect of solvent extraction on antioxidant properties of apricot fruit

Two solvent extraction procedures were used to investigate the extraction efficiency in terms of total antioxidant capacity and total phenols in apricot fruit. Samples were either sequentially extracted with aqueous ethanol (ethanol/water 80% v/v) and tetrahydrofuran or directly extracted with tetrahydrofuran. Each extract was analyzed for total antioxidant capacity by the Trolox Equivalent Antioxidant Capacity (TEAC) assay and total phenols by the Folin-Ciocalteu assay. The results showed that using sequential solvent extraction, the majority (85%) of the total antioxidant capacity and total phenols was due to hydrophilic compounds. In tetrahydrofuran direct extractions, the total antioxidant capacity and total phenols were higher than values obtained with aqueous ethanol and the sum of results obtained from sequential extracts for either total antioxidant capacity or total phenols was similar to the tetrahydrofuran-extract antioxidant values. A linear correlation between total antioxidant capacity and total phenols was found and was independent of the solvent extraction method. In conclusion, the choice of solvent is related to the antioxidant potential of fruit and depends on the food hydrophilic/lipophilic composition.

Antioxidant properties of peel and flesh in ‘GoldRush’ and ‘Fiorina’ scab‐resistant apple (Malus domestica) cultivars

Abstract In the human diet, apples (Malus domestica) are the most consumed fruit worldwide throughout the whole year and are valued for their organoleptic characteristics (aroma, taste, and flavour). Apples are also an important source of phytochemicals, represented by flavonols, flavanols, cinnamic acid, dihydrochalcones, and anthocyanins, which have a known antioxidant activity that can prevent or reduce the insurgence of several chronic and degenerative diseases. These compounds have been found especially in the peel tissue. Apple orchards are often treated chemically against several diseases and particularly against the fungal pathogen Venturia inaequalis. This pathogen causes the growth of small and rough fruits (scab‐apples) with black circular lesions on the peel. New resistant genotypes to V. inaequalis have been obtained but until now they have covered restricted markets aimed at organic production. The aim of this study was to evaluate the quality characteristics of two scab‐resistant cultivars ‘GoldRush’ and ‘Fiorina’, focusing on pomological traits, total antioxidant capacity (TAC), and total phenol (TP) content in the peel and flesh tissues of the fruit. These genotypes were compared with the well‐known cultivar ‘Golden Delicious’ clone B (scab‐susceptible). In all the tested cultivars, TAC and TP content were higher in the peel than the flesh. In particular, the highest TAC and TP values were found in the peel of the two scab‐resistant cultivars, ‘GoldRush’ and ‘Fiorina’, which showed interesting and valuable attributes.

The relationship between xylem differentiation and dormancy evolution in apricot flower buds (Prunus armeniaca L.): the influence of environmental conditions in two Mediterranean areas

Environmental and climatic conditions affect the flower bud growth, flowering and yield performance of fruit species. Temperature and water availability appear to be important factors for temperate fruit trees in mild climates. The aim of this research was to study the involvement of temperature regime on biological processes, such as xylem differentiation and dormancy evolution, in apricot flower buds (Prunus armeniaca L.). Over 3 consecutive years, biological and anatomical investigations were carried out in Tuscany (Italy) and Murcia (Spain) on two cultivars characterized by a different chilling requirement (CR): Currot, a traditional Spanish cultivar with a very low CR, and Stark Early Orange (SEO), a North American cultivar with a very high CR. Currot had a regular bearing, and was characterized by a synchronism between endodormancy release and xylem differentiation. On the other hand, SEO showed an irregular flower bud growth leading to flowering and fruit-set failure, even with a high level of chilling accumulation. No relationship was found in SEO between xylem development and flower bud growth reactivation. The de-synchronism between these processes could determine the poor adaptability to different environmental areas of SEO cultivar, and its very high CR is not the main hypothesised cause of the altered flower bud development.

Morphological structure of the stigma and style of several genotypes of Prunus armeniaca L.

ABSTRACT The morphology of the stigmatic surface and style of apricot (Prunus armeniaca L.) is described, in order to extend current knowledge of stylar and stigmatic structures. Eight apricot cultivars of different geographical origin and characterised by a different self-compatibility behaviour were analysed. Whole pistils were removed from flowers at different phenological stages. Analyses were performed on frozen-hydrated specimens by Low-Temperature SEM. Morphological observations were conducted on: stigma (shape, size and presence of exudate), stigmatic papillae (shape, size, density and distribution) and style (inner structures). A comparative study of the different apricot cultivars showed several morphological differences related to the genotype.

Influence of canopy fruit location on morphological, histochemical and biochemical changes in two oil olive cultivars

The influence of different irradiance conditions was evaluated under natural solar radiation by comparing well-exposed (in) and shaded fruit (out) in canopies of olive trees (Olea europaea L). Over a 2-year period, from 50 days after full bloom up to harvest time, “in” and “out” olive samples of two genotypes (“Frantoio Millennio” and “Coratina 5/19”) were periodically collected. Morphological, histochemical, and biochemical analysis were performed to study the changes on fruit morphometric traits, oil body accumulation, and β-glucosidase enzyme activity. Some parameters were modified by shading inside the canopy in which the proportion of incident photosynthetically active radiation intercepted by the crop was 47%. Shaded fruits developed at slow rate and were characterized by late darkgoing time, reduced size, with a tendency toward oblong shape. The rapid histochemical procedure proposed to estimate the oil body accumulation during fruit ripening showed that a reduced irradiance caused a decrease in oil body density. The canopy position influenced, in a different way, the β-glucosidase activity in relation to the fruit-ripening stage in both genotypes. These findings indicate that providing an adequate and uniform lighting of the olive canopy by careful choices of orchard management practices can be a key factor for several yield components.

Quality and Antioxidant Properties of Apricot Fruits at Ready-to-Eat: Influence of the Weather Conditions under Mediterranean Coastal Area

The effect of different weather conditions on fruit quality of ‘Pisana’ apricot cultivar (Prunus armeniaca L.) was evaluated over seven consecutive harvesting seasons in central Italy. The main physical-chemical traits, total antioxidant capacity and total phenols of fresh apricots at ready-to-eat were studied. The fruit quality showed a high variability in relation to the climatic conditions, particularly due to the summer rainfall. The most influenced quality parameters were TSS, TA and antioxidant levels: under wet seasons a huge reduction was observed, while strong drought conditions increased these chemical compounds. To improve fruit quality, ‘Pisana’ cultivar benefits of environmental conditions typical of temperate and semi-temperate regions, where water is usually limited.