Progettazione e impianto dell'oliveto

The establishment of new olive orchards represents the main way to renovate the olive sector in Italy, because they allow high yields and mechanization of cultural practices, particularly harvesting. The design of an olive orchard implies several important choices (area, cultivar, training system, planting density, orientation of the rows, type of trees) which must be made in relation to several factors, such as farm size, type of product that the grower wants to obtain (commercial target), system to mechanize harvesting, kind of cultivation (conventional, integrated or organic). The application of correct techniques for the preparation of the site, disposal of excessive water, execution of basal fertilization, kind of breaking ploughing to use, execution of the plantation, along with the application of correct cultural practices in the first year after planting, allow to create the best conditions for a fast and intense growth of the trees. All the choices and techniques related to new olive orchards are here reviewed to provide growers and experts a quick, easy-to-read, guide.Realizzato nell'ambito del progetto "Ricerca ed Innovazione per l'Olivicoltura Meridionale", finanziato dal MiPAA

Gluconeogenesis in plants:A key interface between organic acid/amino Acid/Lipid and sugar metabolism

Gluconeogenesis is a key interface between organic acid/amino acid/lipid and sugar metabolism. The aims of this article are four-fold. First, to provide a concise overview of plant gluconeogenesis. Second, to emphasise the widespread occurrence of gluconeogenesis and its utilisation in diverse processes. Third, to stress the importance of the vacuolar storage and release of Krebs cycle acids/nitrogenous compounds, and of the role of gluconeogenesis and malic enzyme in this process. Fourth, to outline the contribution of fine control of enzyme activity to the coordinate-regulation of gluconeogenesis and malate metabolism, and the importance of cytosolic pH in this

Growth Is Inversely Correlated with Yield Efficiency across Cultivars in Young Olive (Olea europaea L.) Trees

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., R2 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

Zinc phosphate protects tomato plants against Pseudomonas syringae pv. tomato

AbstractThe purpose of this study was to determine whether zinc phosphate treatments of tomato plants (Solanum lycopersicum L.) can attenuate bacterial speck disease severity through reduction of Pseudomonas syringae pv. tomato (Pst) growth in planta and induce morphological and biochemical plant defence responses. Tomato plants were treated with 10 ppm (25.90 µM) zinc phosphate and then spray inoculated with strain DAPP-PG 215, race 0 of Pst. Disease symptoms were recorded as chlorosis and/or necrosis per leaf (%) and as numbers of necrotic spots. Soil treatments with zinc phosphate protected susceptible tomato plants against Pst, with reductions in both disease severity and pathogen growth in planta. The reduction of Pst growth in planta combined with significantly higher zinc levels in zinc-phosphate-treated plants indicated direct antimicrobial toxicity of this microelement, as also confirmed by in vitro assays. Morphological (i.e. callose apposition) and biochemical (i.e., expression of salicylic-acid-dependent pathogenesis-related protein PR1b1 gene) defence responses were induced by the zinc phosphate treatment, as demonstrated by histochemical and qPCR analyses, respectively. In conclusion, soil treatments with zinc phosphate can protect tomato plants against Pst attacks through direct antimicrobial activity and induction of morphological and biochemical plant defence responses

Cultivar ideotype for intensive olive orchards: plant vigor, biomass partitioning, tree architecture and fruiting characteristics

In order to achieve higher and earlier yield, modern olive orchards are increasingly intensified, with tree densities up to > 1500 trees hectare-1. With increasing tree densities, individual-tree canopy volume must be proportionally reduced. Not all cultivars are adaptable to high and very high orchard densities, because of excessive vigor and/or insufficient bearing when the canopy is pruned to a small volume. However, what makes an olive cultivar suitable for intensive and super intensive orchards is not clear. Recently, few studies have addressed this topic, suggesting that tree architecture and early bearing are essential traits. Yet, what architectural and productive features are important, how they work and whether they are interrelated remains elusive. This review summarizes and interprets the literature on olive, as well as the more abundant literature available for other fruit species, aiming to provide a comprehensive knowledge framework for understanding how tree architectural characteristics, plant vigor, and fruiting vary across olive genotypes, and how they are interconnected. It is concluded that, among the architectural characteristics, greater branching and smaller diameters of woody structures are particularly important features for cultivar suitability to intensive and super intensive olive orchards. Greater branching allows to produce more fruiting sites in the small volume of canopy allowed in these systems. It also reduces investments in woody structures, liberating resources for fruiting. Additional resources are liberated with smaller structure diameters. Greater branching also increases resources by increasing biomass partitioning into leaves (i.e. the photosynthetic organs), relative to wood. Since yield is affected by the competition for resources with vegetative growth, reducing resource investments in woody structures and/or increasing resource directly, increases yield. Yield, in turn, depresses vegetative growth, reducing vigor and the need for pruning. High yields also produce short shoots which have relatively greater investments in leaf mass and area, and lower in the woody stem, making them more suitable than long shoots to support concurrent fruit growth. This single framework of interpretation of how the different architectural and fruiting characteristics work and interact with one-another, will provide guidance for cultivar selection and breeding for intensive and super intensive olive orchards

Partitioning of Dry Matter into Fruit Explains Cultivar Differences in Vigor in Young Olive (Olea europaea L.) Trees

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 (R2 = 0.90). The regressions improved further when data from 2015 only were used (R2 = 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

Neem Oil Used as a "Complex Mixture" to Improve In Vitro Shoot Proliferation in Olive

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

Antioxidants in processed fruit, essential oil, and seed oils of feijoa

The degradation of nutraceutical properties during processing of the fruits of feijoa (Acca sellowiana), and the characterization of seed oils, and volatile compounds were evaluated. In feijoa fruit dehydrated by a standard convective air process, the total phenols and total flavonoids declined 42%, and the antioxidant capacity determined by ABTS, DPPH, and FRAP declined 26% with respect to lyophilized fruit. In feijoa jam, the reduction of total phenols and flavonoids was 52%, and the reduction in antioxidant capacity was 72%. Vitamin C in the jam was also reduced by the processing. Feijoa seeds had 69.4% unsaturated fatty acids, mainly linoleic (46.2%) and linolenic (3.7%) acids. Behenic acid was also detected in the seeds but in small amounts (0.91%). The feijoa skin had 31 volatile compounds in two orchards with different climate, one in a tropical highland and the other in a temperate zone. The extraction yield was on average 0.45%. The major compounds in the essential oil of the feijoa skin were 3-hexen-1-yl benzoate, elixene, spathulenol, D-germacrene and alpha-cadinol. In general, the concentration of volatile oils was higher in the temperate zone

Front. Plant Sci.

Temperature, water, solar radiation, and atmospheric CO2 concentration are the main abiotic factors that are changing in the course of global warming. These abiotic factors govern the synthesis and degradation of primary (sugars, amino acids, organic acids, etc.) and secondary (phenolic and volatile flavor compounds and their precursors) metabolites directly, via the regulation of their biosynthetic pathways, or indirectly, via their effects on vine physiology and phenology. Several hundred secondary metabolites have been identified in the grape berry. Their biosynthesis and degradation have been characterized and have been shown to occur during different developmental stages of the berry. The understanding of how the different abiotic factors modulate secondary metabolism and thus berry quality is of crucial importance for breeders and growers to develop plant material and viticultural practices to maintain high-quality fruit and wine production in the context of global warming. Here, we review the main secondary metabolites of the grape berry, their biosynthesis, and how their accumulation and degradation is influenced by abiotic factors. The first part of the review provides an update on structure, biosynthesis, and degradation of phenolic compounds (flavonoids and non-flavonoids) and major aroma compounds (terpenes, thiols, methoxypyrazines, and C13 norisoprenoids). The second part gives an update on the influence of abiotic factors, such as water availability, temperature, radiation, and CO2 concentration, on berry secondary metabolism. At the end of the paper, we raise some critical questions regarding intracluster berry heterogeneity and dilution effects and how the sampling strategy can impact the outcome of studies on the grapevine berry response to abiotic factors