Although information is available regarding the content of various metabolites such as sugars and organic/amino acids in blackberry (Rubus L.), little is known about its enzyme composition. The aim of this study was to investigate changes in the abundance of various enzymes during the ripening of blackberry. Blackberry is an aggregate fruit, composed of a receptacle and several drupelets attached to it, which in turn, are composed of the flesh (mesocarp plus epicarp) and seed enclosed in the endocarp; therefore, these parts were analyzed separately along with the pedicel. The enzymes studied participate in organic/amino acid and sugar metabolism and photosynthesis, processes known to be important in fruit development. These enzymes were phosphoenolpyruvate carboxykinase [PEPCK (EC:184.108.40.206)], phosphoenolpyruvate carboxylase [PEPC (EC:220.127.116.11)], pyruvate, orthophosphate dikinase [PPDK (EC:18.104.22.168)], cytosolic aspartate aminotransferase [cyt AspAT (EC:22.214.171.124)], aldolase (EC:126.96.36.199), glutamine synthetase [GS (EC:188.8.131.52)], and ribulose-1,5-bisphosphate carboxylase/oxygenase [RUBISCO (EC:184.108.40.206)]. To avoid problems in measuring enzyme activity, the approach taken was to use antibodies specific for each enzyme in conjunction with immunoblotting of sodium dodecyl sulfate polyacrylamide gel electrophoresis. During ripening, there were marked changes in abundance of several of these enzymes and these changes were dependent on the tissue investigated. PEPCK appeared when organic acids decreased in the flesh and was only detected in this tissue, whereas PPDK was not detected in any tissue. In the flesh, there was a large decrease in abundance of RUBISCO, plastidic GS, and plastidic aldolase, but little change in cytosolic GS, cytosolic aldolase, and PEPC. In seeds, there was a decrease in the abundance of all enzymes. In the receptacle and pedicel, apart from a large decrease in RUBISCO in the receptacle, there was little change in enzyme abundance.
Adolfo Rosati, Andrea Paoletti, Giorgio Pannelli and Franco Famiani
The modern olive industry is increasingly interested in olive cultivars that start producing early and remain relatively small, because they are suitable for super high-density orchards. Some cultivars are better suited to this than others but it is not clear why. Understanding the mechanisms that lead to early production and reduced canopy size is therefore important. The object of this study was to investigate whether differences in vigor across olive cultivars are related to earliness and abundance of bearing. We analyzed tree growth and productivity in young coetaneous trees of 12 olive cultivars, grown together in the same orchard. Trunk diameter increased over the observation period, reaching significantly different values across cultivars. Canopy volume also increased, reaching 2-fold differences between the minimum and the maximum values. Cumulative yield increased, reaching up to 3-fold differences. When the cumulative yield at the end of the experiment was plotted against the final trunk diameter, no correlation was found. A significant correlation was found when cumulative yield was plotted against the increment in trunk diameter during the observation period for which yield data were collected. This relationship improved (i.e., R 2 rose from 0.57 to 0.83) when yield efficiency [i.e., cumulative yield per unit of final trunk cross-sectional area (TCSA) or per unit of canopy volume] was used instead of yield. These results clearly showed that trees that produced proportionally more (i.e., higher yield efficiencies) grew less. We conclude that, in young olive trees, vigor is inversely related to early bearing efficiency, which differs significantly across cultivars. The results support the hypothesis that early and abundant bearing is a major factor in explaining differences in vigor across olive cultivars.
Juan Guillermo Cruz-Castillo, Juan Ángel Tinoco-Rueda and Franco Famiani
The fruit of Persea schiedeana is consumed in various rural regions of Mexico and Central America and is mainly sold in local markets. Information regarding the ecological conditions where it grows and the potential for its distribution in Mexico has been little studied. The States of Chiapas, Hidalgo, Oaxaca, Puebla, Tabasco, and Veracruz in Mexico were explored to locate P. schiedeana trees. The ecological conditions of the places where P. schiedeana was found were characterized using thematic cartography and by evaluating the ecological niches to identify potential areas for its distribution. The trees were found in wide physiographic, geological, and edaphic conditions, but they were primarily located in semiwarm humid and warm humid climates. Persea schiedeana trees grow from almost sea level to 2000 m in altitude. Zones with the best developmental conditions for P. schiedeana were in the region of the high mountains in the center of Veracruz and the highland zone of northern Oaxaca. The oil obtained from the fruit of P. schiedeana trees growing at 1300 m had high oleic acid content. This wild fruit has the potential for obtaining new products for cosmetic and alimentary industries.
Jorge Andres Agustin, Matha Soto, Franco Famiani and Juan Guillermo Cruz-Castillo
Fifty-six accessions of white sapote (Casimiroa edulis Llave & Lex.) grown in situ in 11 municipalities in the state of Michoacán, Mexico, were characterized using 14 morphometric variables (six of fruit and eight of seed). There was a high cv for fruit weight (0.50), the number of developed seeds (NDS) (0.48), and total seed weight (0.45). Principal component analysis (PCA) showed that the main differences among the C. edulis accessions were fruit weight, seed projected area, Feret diameter (FD), the length of polar and equatorial axes of the fruit, the number of undeveloped seeds (NUS), the NDS, hardness of the skin (HS), and total soluble solids content of the fruits. Three groups of accessions were determined by cluster analysis (CA). The first group was made up of 53 accessions with intermediate values of fruit size and seed size. The second group, comprising two accessions, had the lowest values of fruit size. The third group showed an outstanding individual with the highest values for fruit size/weight, seed weight, and total soluble solids. Through an in-depth examination of the genotypes of the first group, four genotypes were identified for their positive characteristics. The results indicate an extremely high variability in the fruit and seed characteristics produced by different trees/genotypes of white sapote in Mexico. Hence, an initial, preliminary individuation/selection of five genotypes could be considered for the development of new cultivars for establishing white sapote orchards in Mexico.
Adolfo Rosati, Andrea Paoletti, Raeed Al Hariri, Alessio Morelli and Franco Famiani
Low vigor and early and abundant production are desirable traits for modern tree crops. In olive, most cultivars are too vigorous and cannot be successfully constrained in the small volume allowed by the straddle harvester used in the so-called superhigh-density (SHD) orchards. Only few cultivars appear to have sufficiently low vigor to be suitable for this system. These cultivars combine low vigor with earlier and higher yield. This study investigated the hypothesis that differences in vigor between Arbequina, a low vigor and the most commonly used cultivar in SHD orchards, and Frantoio, a highly vigorous cultivar not suitable for such orchards, are related to their differences in early bearing and consequent differences in dry matter partitioning into fruit. Young trees of both cultivars were deflowered either in 2014, 2015, both years, or neither one, resulting in a range of cumulative yields over the 2 years. Tree trunk cross-sectional area (TCSA) was measured at the beginning of each year. This was closely related to total tree mass, as assessed at the beginning and at the end of the experiment. Cumulative yield, in terms of fruit dry matter, was also assessed. TCSA increased less in fruiting trees in both years. As expected, when not deflowered, ‘Frantoio’ was less productive and more vigorous than ‘Arbequina’. However, there was no difference in TCSA increment when both cultivars were completely deflowered. TCSA increments were closely inversely related to yield across all treatments and cultivars (R 2 = 0.90). The regressions improved further when data from 2015 only were used (R 2 = 0.99). The results represent the first quantitative report showing that differences in vigor among cultivars can be completely explained in terms of different dry matter partitioning into fruit, supporting the hypothesis that early bearing is a major cause, rather than merely a consequence, of lower vigor in young ‘Arbequina’ trees. These results provide new understanding on vigor differences across cultivars, which will be useful for breeding and selection of new genotypes.
Maurizio Micheli, Daniel Fernandes da Silva, Daniela Farinelli, Graziana Agate, Rafael Pio and Franco Famiani
Shoots of the olive cultivar Moraiolo were previously cultured in aseptic conditions on Olive Medium (OM), with the addition of 4 mg·L−1 of zeatin, 30 g·L−1 of sucrose, and 7 g·L−1 of agar. Then, 1-cm long uninodal explants with two leaves and two axillary buds were excised from the proliferated masses and placed on the same proliferation medium enriched with four concentrations of neem oil (0—control, 0.1, 0.5, and 1.0 mL·L−1), added before sterilization. The addition of 0.1 mL·L−1 of neem oil to the medium gave an improvement in shoot regeneration. More vigorous shoots (longer proliferated shoots) were obtained along with a higher number of nodes (multiplication rate). Overall, there was a significant increase in the total fresh and dry proliferated weights. To our knowledge, this is the first report showing a strong and beneficial effect of neem oil, used as a “complex mixture,” on in vitro plant regeneration.
Oscar Andrés Del Angel-Coronel, Juan Guillermo Cruz-Castillo, Javier De La Cruz-Medina and Franco Famiani
In terms of color, firmness, respiration, and ethylene production during the postharvest period, ripening is here characterized for the first time in the fruit of Persea schiedeana Nees. The results show a respiratory peak (respiratory climacteric) and an ethylene production peak, indicating that the fruit of P. schiedeana can be classified as climacteric. The fruit ripened rapidly, and senescence effects appeared 5 days after harvest. Together with appreciable weight loss during the postharvest period, this makes the fruit very perishable. Preliminary values for quantitative ripening indices are provided (fruit firmness, color lightness, hue angle, and chroma).
Simona Proietti, Stefano Moscatello, Fiorella Villani, Federica Mecucci, Robert P. Walker, Franco Famiani and Alberto Battistelli
Key nutritional characteristics of the fruit flesh of 41 sour cherries growing in the region of Umbria in central Italy have been determined. Fruit size, flesh dry matter content, nonstructural carbohydrates, organic acids, and anthocyanins were the analyzed parameters. Both the growing environment and genotype were statistically significant for most of the characteristics. Morello sour cherries were characterized by a large amount of sorbitol (up to 44.2 mg·g−1 FW), which contributed significantly to the dry matter content of the flesh, malic acid content that was higher (up to 48.4 mg·g−1 FW) than any published values for cherry flesh, and high anthocyanin content (up to 383.4 mg per 100 g FW). Cyanidin 3-glucosyl rutinoside was the most abundant compound. The analyzed germplasm could be the basis for breeding programs and new industrial products with high nutritional value.