R. Viti

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’.

The self compatibility trait of the main apricot cultivars and new selections from breeding programmes.

SummaryKnowledge of the self-compatible trait for commercial apricot cultivars and selections from breeding programmes is of great importance for apricot breeders and growers. A study on self-incompatibility of the main growing cultivars in Europe as well as selections from European and American breeding programmes has been carried out. Out of 123 cultivars tested, 72 were found to be self-compatible while 42 were self-incompatible. For nine cultivars results were not conclusive. Many of the self-incompatible cultivars were obtained from breeding programmes, which indicates that not enough attention has been paid to this undesirable characteristic during the selection processes.

Physiological characterization of two peach seedling rootstocks in bicarbonate nutrient solution. I. Root iron reduction and iron uptake

Investigations were conducted on two peach seedling rootstocks, Nemaguard and TXR4989-2 (hybrid Titan × Nemared’), grown in bicarbonate-containing nutrient solution with 50 μM Fe-DTPA. Root-associated Fe(III)-reductase activity and iron absorption were determined to elucidate the physiological differences which cause the different tolerance of the two rootstocks in calcareous soils. Reductase activity was detectable in intact plants after several weeks and visualized on excised roots in gelrite medium. The physiological responses of NMG and TXR rootstocks suggest that stress conditions increase the Fe-reduction capacity and the iron uptake enormously. Both assays indicated interesting differences in behaviour between rootstocks.

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.

Lime‐induced chlorosis in quince rootstocks: Methodological and physiological aspects

Abstract Two quince rootstocks for pear, clone MA and Ct.S.306, were screened to evaluate their threshold tolerance rate to lime‐induced chlorosis. Another important objective was to correlate the results of a chlorophyll analysis with observed chlorosis symptoms. The ron content in leaves was insufficient to determine the amount of iron available to the plant. The use of sodium bicarbonate (NaHCO3) in the hydroponic culture of pear was found to be the preferable over calcium carbonate (CaCO3) because of its higher solubility.

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.

Application of tissue culture on quince rootstock in iron‐limiting conditions 1

Abstract Two quince rootstocks for pear, clones “MA”; and “Ct.S.212”;, were screened under iron (Fe)‐limiting conditions in in vitro culture. The most important objectives of this work were: first, to develop use of the tissue culture technique as a rapid screening methodology for evaluation of Fe efficiency in quince, and second, to identify morphophysiological characters associated with variation in response. Iron content of the MS medium (200 meq FeEDTA) was reduced to 80%, 65%, 50%, 25%, and 15% of standard content in order to induce chlorosis symptoms. Results showed that “Ct.S.212”; presented a higher proliferation rate and greater growth than clone “MA”; in the 15 and 25% Fe treatments, but clear symptoms of chlorosis were observed in both clones at the two lowest Fe concentrations. Parameters of vegetative development commonly used in in vitro culture proved to be difficult to interpret for this type of screening, and further tests will be necessary. In contrast, type and content of chlorophyll we...