Search Results (437)

The olive tree (Olea europaea L.), a cornerstone of Mediterranean agriculture, is widely recognized for its inherent drought tolerance. However, the increasing frequency and intensity of water deficit events driven by climate change are challenging its growth, productivity, and long-term sustainability. This review synthesizes current knowledge on the morphological and phenological adaptations of olive trees to water stress. In fact, under drought conditions, olive trees develop a suite of structural and anatomical adjustments that collectively enhance water-use efficiency and help maintain plant water status. These adjustments include reduced leaf area, thickened cuticles, mesophyll rearrangements, remodeling of xylem vessel architecture, and reinforced root systems. These morpho-anatomical responses influence phenology, through changes in the timing and duration of key phenological stages, leading to reduced flower induction, lower flowering intensity, decreased fruit set, and overall lower yields, while the most pronounced effects are observed in sensitive cultivars. Among all stages, flowering is the most vulnerable to water deficit, while pit hardening and fruit development show comparatively more tolerance. The combination of morphological, anatomical, and phenological responses could provide a mechanistic elucidation of drought tolerance variability within olive cultivars. Understanding this interplay is likely to offer valuable criteria in selecting and breeding resistant varieties, thus ensuring productive and sustainable olive cultivation under increasingly severe climatic conditions. Full article

The olive tree (Olea europaea L.) is a keystone species in Mediterranean agroecosystems, where it plays a central economic and cultural role. However, the Mediterranean Basin is increasingly exposed to climate change, with rising temperatures and prolonged droughts threatening the long-term sustainability of olive cultivation. Understanding the adaptive responses of olive trees to water scarcity is critical for ensuring resilience in olive-based agroecosystems. This study investigates the functional responses of the Moroccan Menara olive cultivar under different controlled deficit irrigation (DI) strategies, namely regulated (RDI) and sustained (SDI) deficit irrigation. By analyzing key leaf functional and biochemical traits, we assessed how varying levels of water stress influence resource allocation and stress mitigation mechanisms. Under full irrigation (100% of crop water evapotranspiration) throughout the growing season and during sensitive growth periods, trees exhibited increased stomatal density, leaf area, and higher leaf carbon, nitrogen, and phosphorus contents, traits associated with enhanced growth and photosynthetic capacity. Meanwhile, under RDI treatments, with a 20% water reduction during sensitive periods and 40% during non-sensitive periods, Menara trees showed increased leaf tissue density and accumulation of polyphenols. SDI treatments, however, triggered higher concentrations of osmoprotectants (glycine, sugars, and proline), reduced stomatal density, and smaller leaf area associated with increased stomatal size. Principal component analysis revealed a major trade-off between growth-related and stress-protective traits, primarily driven by water availability during phenological growth stages. Notably, the strength of this trade-off was positively associated with olive fruit yield, underscoring the importance of strategically timed irrigation in balancing physiological resilience and productivity. These findings emphasize the crucial role of irrigation strategy in modulating functional responses of olive trees to water deficit, offering insights into optimizing water use under future climate scenarios. Full article

Olive (Olea europaea L.) is an important woody oil crop worldwide, and accurate estimation of leaf chlorophyll content is critical for assessing nutritional status, photosynthetic capacity, and precision crop management. Unmanned aerial vehicle (UAV) remote sensing, with high spatiotemporal resolution, has increasingly been applied in crop growth monitoring. However, the small, thick, waxy leaves of olive, together with its complex canopy structure and dense arrangement, may reduce estimation accuracy. To identify sensitive features related to olive leaf chlorophyll and to evaluate the feasibility of UAV-based estimation methods for olive trees with complex canopy structures, UAV multispectral orthophotos were acquired, and leaf chlorophyll was measured using a SPAD (Soil Plant Analysis Development) meter to provide ground-truth data. A dataset including single-band reflectance, vegetation indices, and texture features was built, and sensitive variables were identified by Pearson correlation. Modeling was performed with linear regression (LR), Random Forest (RF), Extreme Gradient Boosting (XGBoost), Partial Least Squares Regression (PLSR), and Support Vector Machine (SVM). Results showed that two spectral bands (green and red), one vegetation index (TCARI/OSAVI), and twelve texture features correlated strongly with SPAD values. Among the machine learning models, XGBoost achieved the highest accuracy, demonstrating the effectiveness of integrating multi-feature UAV data for complex olive canopies. This study demonstrates that combining reflectance, vegetation indices, and texture features within the XGBoost model enables reliable chlorophyll estimation for olive canopies, highlighting the potential of UAV-based multispectral approaches for precision monitoring and providing a foundation for applications in other woody crops with complex canopy structures. Full article

The study aimed to identify mineral determinants of potential therapeutic effects of Olea europaea L. leaves from introduced cultivars of the Southern Coast of Crimea and to assess their suitability for functional aqueous tisanes. Using ICP-OES, eighteen macro- and micro-elements were identified in dried leaves, with K and Ca predominant (>10.0 g/kg), followed by P, S, and Mg (>1.0 g/kg). Maximum values occurred in ‘Nikitskaya’ (K 15.6 g/kg; S 2.05 g/kg; and P 1.97 g/kg) and ‘Tlemcen’ (Ca 18.6 g/kg and Mg 1.46 g/kg). Extractability into infusion (2 g/100 mL, 60 min) reached 325 mg/L for K, 26 mg/L for Ca, 48 mg/L for S, 18 mg/L for P, and 9 mg/L for Mg. Potentially toxic elements were below detection limits, indicating the safety of both the raw material and beverage. Principal component, correlation, and Ward clustering analyses highlighted ‘Nikitskaya’, ‘Lomashenskaya’, and ‘Coregiolo’ as having the highest cumulative mineral value among the tested six cultivars. Overall, the findings support the feasibility of olive-leaf tisanes as accessible sources of K, Ca, S, P, and Mg, with potential contributions to antioxidant defense, blood-pressure regulation, and lipid and carbohydrate metabolism. Full article

Sesame bacterial wilt, caused by the pathogen Ralstonia solanacearum, is a major constraint for continuous cropping. Deciphering the defense mechanisms of sesame is therefore essential to the development of novel and effective control strategies. The Non-expressor of Pathogenesis-Related 1 (NPR1) plays a key role in regulating salicylic acid (SA)-mediated systemic acquired resistance (SAR). In this study, we reported that leaf treatments with 50 μg/mL benzothiadiazole (BTH) resulted in increased protection of sesame against Ralstonia solanacearum. We clarified the structure, expression patterns, and function of a NPR1 homologous gene, SiNPR1, in sesame. The SiNPR1 gene open reading frame comprises 1758 bp, and it encodes 585 amino acids. Phylogenetic analysis revealed that SiNPR1 is closely related to NPR1-like in Olea europaea and clustered with other members of the families Monocotyledon and Dicotyledon. Quantitative real-time PCR (qRT-PCR) results demonstrated that the expression of the SiNPR1 gene was organ-specific and could be induced by BTH. The yeast two-hybrid assay confirmed that SiNPR1 directly interacts with SiTGA2. In conclusion, these results suggest that SiNPR1 plays a pivotal role in the BTH-dependent systemic acquired resistance in sesame. Full article

Increasing the tocopherol content in plant-derived foods not only improves their nutritional quality but may also enhance plant resilience against abiotic stress factors. Tyrosine catabolism is the origin of homogentisic acid, which constitutes the core aromatic ring in the structure of tocopherols. Two olive tyrosine aminotransferase genes, OeTAT1 and OeTAT2, have been cloned, and the corresponding recombinant proteins have been functionally validated. Both proteins showed significant differences in substrate specificity and catalytic efficiency. OeTAT1 protein exhibited a marked substrate preference for tyrosine (K_m 0.57 mM and V_max of 47.61 U mg⁻¹), forming 4-hydroxyphenyl pyruvic acid, which is the direct precursor of homogentisic acid. On the contrary, OeTAT2, with significantly lower catalytic activity, displayed broad substrate specificity and was less efficient with tyrosine (K_m 6.80 mM and V_max 5.72 U mg⁻¹). The expression analysis of OeTAT1 and OeTAT2 during the development and ripening of fruits in seven olive cultivars, as well as in olive trees grown under water stress, suggests different roles for both genes. The data suggest that OeTAT1 seems to play a key role in tocopherol biosynthesis during olive fruit development, while OeTAT2 may be more closely associated with other metabolic pathways unrelated to tocopherol biosynthesis. Furthermore, both genes were found to be upregulated under water stress conditions in olive. Full article

Background/Objectives: Olive leaf (Olea europaea L.), a by-product of olive oil production, is rich in bioactive phenolics but limited in application due to poor solubility and stability. To improve their bioavailability, this study presents a comparative encapsulation strategy using three phospholipid-based liposomal systems (AL, PG90, and PH90) loaded with ethanolic olive leaf extract. Methods: Liposomes were characterized by physicochemical parameters, encapsulation efficiency (EE), antioxidant activity, morphology, release kinetics under simulated physiological conditions, and 60-day stability. To the best of our knowledge, this is the first direct comparison of AL, PG90, and PH90 matrices for olive leaf extract encapsulation. Results: HPLC and GC-MS confirmed successful encapsulation, with oleuropein showing the highest EE (up to 76.18%). PH90 favored retention of non-polar triterpenes, while AL and PG90 preferentially encapsulated polar flavonoid glycosides. FT-IR analysis verified extract integration into phospholipid bilayers. Antioxidant activity remained high in all loaded formulations, with negligible activity in empty liposomes. Extract-loaded systems exhibited reduced particle size, higher viscosity, and more negative electrophoretic mobility, enhancing colloidal stability. PG90 liposomes displayed the most stable mobility profile over 60 days. Transmission electron microscopy and nanoparticle tracking analysis revealed formulation-dependent vesicle morphology and concentration profiles. Release studies demonstrated significantly prolonged polyphenol diffusion from PG90 liposomes compared to the free extract. Conclusions: Phospholipid composition critically governs encapsulation selectivity, stability, and release behavior. Tailored liposomal systems offer a promising strategy to enhance the stability and delivery of olive leaf polyphenols, supporting their application in bioactive delivery platforms. Full article

The increasing demand for sustainable substrates in agriculture and urban greening calls for alternatives to peat, whose extraction poses significant environmental risks. This study assesses the potential of olive pomace biochar (OB), wood biochar (WB), and green compost (GC), alone or in combination, to partially replace peat in growing media and improve substrate properties and plant development. Ten different substrates were formulated by substituting 10–20% of a commercial peat-based substrate with these organic amendments, using the commercial substrate alone as a control. The effects of such replacements were evaluated in the following experiments: a germination test conducted in Petri dishes using four forage species (Medicago polymorpha, Lolium perenne, Festuca arundinacea, and Lolium rigidum); and two parallel pot experiments lasting 100 days each (one with M. polymorpha and L. perenne, and another with young Olea Europaea var. Arbequina saplings). This study evaluated the impact on plant development, as well as the physical properties and composition of the substrates during the incubation process. Germination and survival of forage species were comparable or improved in most treatments, except those including 20% OB, which consistently reduced germination—likely due to high electrical conductivity (>10dS/m). In the pot experiments, substrate pH and total carbon content increased significantly with biochar addition, particularly with 20% WB, which doubled total C relative to control. Both forage species (Medicago polymorpha and Lolium perenne) and the olive saplings (Olea Europaea) exhibited normal growth, with no significant differences in biomass, water content, or physiological stress indicators when compared to the control group. Nutrient uptake was found to be stable across treatments, although magnesium levels were below sufficiency thresholds without triggering visible deficiency symptoms. Overall, combining compost and biochar—particularly WB and GC—proved to be a viable strategy to reduce peat use while maintaining substrate quality and supporting robust plant growth. This approach proved effective across the different plant varieties tested, including Medicago polymorpha, Lolium perenne, and young olive plants, which together encompass a wide spectrum of agronomic and horticultural applications as well as contrasting growth and nutrient requirements. Adverse effects on early plant development can be avoided by carefully selecting and characterizing biochars, with specific attention to salinity and C/N ratio. This finding is crucial for the successful large-scale implementation of sustainable alternatives to peat. Full article

The olive tree has exceptional agricultural and economic importance in Mediterranean regions due to its fruit, which is used to produce olive oil. However, the olive oil industry generates a significant amount of waste, including leaves from Olea europaea L. These leaves contain a high concentration of bioactive compounds, predominantly phenolic ones, which are well known for their antioxidant properties and health benefits. Determining antioxidant capacity involves the use of different assays based on absorbance (DPPH, 2,2-diphenyl-1-picrylhydrazyl; and ABTS, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and fluorescence (ORAC, Oxygen Radical Absorbance Capacity), which require reagents and long waiting times. Therefore, having a non-destructive technique capable of providing this information would be useful. To explore this, 120 olive leaf samples were analyzed using the three antioxidant assays to quantify their total antioxidant capacity. Predictive models were successfully developed for each of the three methods, achieving coefficients of determination (R²) between 0.9 and 1 across calibration, validation, and prediction. Additionally, high residual predictive deviation (RPD) values were obtained, indicating that the models exhibit strong reliability and predictive performance. Full article

The olive tree (Olea europaea L.) has been cultivated for millennia, with olive oil representing both a cornerstone of the Mediterranean diet and a major agricultural commodity. Its composition, rich in monounsaturated fatty acids, polyphenols, tocopherols and squalene, supports well-documented cardioprotective, antioxidant and anti-inflammatory benefits. Olive oil production generates substantial secondary streams, including pomace, leaves, pits and mill wastewater, which are rich in phenols, triterpenes and fibers. This review consolidates recent advances in their phytochemical characterization, innovative extraction technologies and health-promoting effects, while highlighting the economic and regulatory prospects for industrial adoption. Comparative analysis shows that olive leaves can produce up to 16,674.0–50,594.3 mg/kg total phenolics; oleuropein 4570.0–27,547.7 mg/kg, pomace retains 2.24 g GAE/100 g dried matrix (DM)total phenolics; oil 13.66% DM; protein 6.64% DM, and wastewater contains high concentration of phenolics content of olives. Innovative extraction techniques, such as ultrasound and microwave-assisted methods, allow for a recovery, while reducing solvent use and energy input. The analysis highlights opportunities for integrating these by-products into circular bioeconomy models, supporting the development of functional foods, nutraceutical applications and sustainable waste management. Future research should address techno-economic feasibility, regulatory harmonization and large-scale clinical validation to accelerate market translation. Full article

Climate change poses serious challenges to Mediterranean crops such as the olive tree (Olea europaea L. subsp. europaea), underscoring the need for cultivars with improved drought tolerance and disease resistance. This study investigates variability in leaf and wood traits among Moroccan and introduced olive cultivars and their crossbreed genotypes grown under similar conditions. Specifically, we assessed (1) variation in key functional traits, (2) the effects of crossbreeding combinations, and (3) trait syndromes shaped by selection. Results showed substantial intraspecific variation in leaf traits, including specific leaf area (SLA), specific leaf water content (SLWC), stomatal size (SS), and density (SD), indicating diverse strategies for resource use and plasticity. Crossbreed genotypes generally displayed higher SLWC and lower SLA, reflecting adaptation to water stress. Wood traits, particularly vessel size (SVS) and number (NVS), also varied, revealing trade-offs between hydraulic efficiency and safety. Notably, an increase in vessel size and hydraulic conductivity was correlated with oil content (OC%), while OC% increased with higher vessel and stomatal densities. Larger stomata increased conductance and fruit growth, while lower SLA was linked to higher yield. Multivariate analysis distinguished two genotype groups, consistent with parental combinations. Overall, crossbreeding generated novel functional diversity that may enhance adaptive potential. These findings highlight the value of integrating functional and anatomical traits into olive breeding programs to improve resilience and productivity under climate change. Full article

The adaptability of several Italian olive cultivars to high-density cultivation was evaluated from 2020 to 2024 in central Italy by assessing their agronomic behavior, with the aim of identifying which Italian olive cultivars can combine high productivity and suitability for intensive mechanization—through high- and very high-density planting systems—allowing biodiversity valorization. The cultivars were Borgiona, Don Carlo, FS17, Gentile di Anghiari, Gentile di Montone, Giulia, Leccio del Corno, Maurino, Moraiolo, Pendolino, Piantone di Falerone, and Piantone di Mogliano. The international cultivar Arbequina was used as a reference. The olive orchard was planted in 2015, at a tree spacing of 5 m × 2 m (1000 trees/ha). Arbequina was found to have limited vigor and high production efficiency, as reported in other works, therefore confirming its suitability for high-density and super-high-density cultivation. Some cultivars, such as Leccio del Corno, Maurino, FS17, Piantone di Mogliano, and Piantone di Falerone, had a production and yield efficiency that was not different from or even higher than Arbequina. Other cultivars found to be promising were Don Carlo and Gentile di Anghiari, which had a slightly lower productive performance than Arbequina. Overall, the results are encouraging and suggest that some of these cultivars may be suitable candidates for high- and super-high-density olive orchards. This suitability is further supported by their favorable fruit characteristics, which appear to facilitate efficient mechanical harvesting. However, additional data is necessary to enable a more comprehensive assessment of these cultivars, particularly their capacity to maintain canopy dimensions compatible with straddle harvester operation, while maintaining a stable vegetative–reproductive balance over time. Full article

After a brief review of the concept of fertility in antiquity—from mythological, historical, religious, and artistic perspectives—this conceptual review examines the evolution of the notion of fertility in fruit growing, considering both its biological and agronomic dimensions. The discussion addresses the phenomena underlying the production process and the quantitative and qualitative yields of fruit trees, including the interactions between vegetative growth and reproductive aspects, as well as various interferences—such as alternate bearing or sterility—that mediate between potential and actual fertility. These aspects are analyzed in light of both well-established studies and the most recent research findings. Furthermore, a holistic and comprehensive approach is presented, aiming to transcend the limitations of a purely biological interpretation and to clarify certain ambiguities in the use of the term “fertility,” with particular focus on the physiology of flowering and fruiting in a paradigmatic Mediterranean fruit tree species (Olea europaea L. subsp. europaea var. europaea). Finally, the potential contributions of recent advances in the understanding of flowering and fruiting biology are discussed, particularly in relation to genetic improvement and the development of simulation models for the bio-agronomic behavior of fruit trees. Future perspectives are also explored, especially regarding bio-agronomic strategies to address alternate bearing. Full article

Somatic embryogenesis (SE) is a powerful biotechnological tool for large-scale clonal plant propagation. However, most woody species exhibit a recalcitrant response. Olea europaea L., a highly valuable tree crop, is among these recalcitrant species. Unravelling the molecular mechanisms underlying SE efficiency in O. europaea is, therefore, essential. Access to embryogenic lines with contrasting capacities for somatic embryo differentiation is a key requirement for such studies. Mature fruits of olive cultivars ‘Galega Vulgar’ and ‘Arbequina’ were collected from open-pollinated orchard-grown plants, and various explants taken from zygotic embryos were used to establish SE. A differentiated response was observed both within each cultivar and between cultivars, with cv. ‘Arbequina’ showing the highest embryogenic induction, particularly when radicles were used. Secondary SE was successfully established for both high- and low-efficiency lines, providing valuable material for future molecular studies. Somatic embryo conversion into plants, a key indicator of embryo quality, was successfully achieved in both cultivars. Flow cytometry analysis revealed a high degree of chromosomal stability. This study presents a reliable procedure to obtain and maintain distinct embryogenic responses in O. europaea, identifying lines with both high and low embryogenic efficiency that can serve as model systems for future molecular investigations. Full article

This study investigates the changes in mechanically harvested ‘Leccino’ olives stored under cold and room-temperature conditions from harvest up to 23 days of storage during two consecutive seasons. Variations in quality parameters, including maturity index, weight, firmness, and colour, were monitored throughout the storage period. In addition, the phenolic profile of the olives was analysed using HPLC, and the fatty acid composition was determined by GC–MS. These analyses enabled a comparison of changes across different storage durations, seasons, and storage conditions. Results show that fruit ripeness at harvest differed notably between the two seasons. In the second season, the olives displayed a higher maturity index, lower firmness, and lower content of certain individual phenolic compounds, indicating a more advanced stage of ripening compared to that of the previous year. These initial differences strongly influenced the subsequent development of fruit quality and biochemical characteristics during storage. Storage temperature had a significant effect on the quality parameters and metabolism. As expected, olives stored at room temperature lost their firmness and weight more quickly than those stored under cold conditions. The most abundant phenolic in olive fruit, oleuropein, degraded more rapidly at room temperature, resulting in a quicker accumulation of its derivatives. Fatty acids were more stable than phenolic compounds during storage, likely due to their lower susceptibility to enzymatic degradation and oxidative reactions under the tested conditions. While saturated fatty acids remained largely unchanged, a slight increase in unsaturated fatty acids was observed after 23 days of cold storage, possibly as a result of adaptations of the membrane to cold storage conditions. Full article