From ancient olice agroforestry systems to modern conventional and organic olive monocultures: historical evolution of greenhouse gas emissions

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Erratum to "Selenium as stressor and antioxidant affects pollen performance in Olea europaea" [FLORA 215 (2015) 16–22]

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Selenium as stressor and antioxidant affects pollen performance in Olea europaea

Abstract Selenium (Se) as an antioxidant is a trace element essential to wellness and the maintenance of human health. Although it has not been confirmed to be an essential micronutrient in higher plants, there is increasing evidence of its benefits in plants in which it inhibits the detrimental effects of environmental stressors, while only few studies refer to its action on pollen germination. Selenium enhances the stress tolerance regulating the production and quenching of reactive oxygen species (ROS); however, the endogenous ROS are essential to the cross-talk between pollen and stigma and promote pollen tube growth. The action of Se has many mechanisms, not all yet fully clarified. In order to deepen the knowledge and fill the gaps in the role of Se as an inhibitor of ROS and, at the same time, a promoter of pollen germination, we attempted this research, enriching olive trees growing in pots and in the field with Se. The plants in pots were kept at a controlled water regime in order to induce drought stress. To test the effect of antioxidant on pollen performance, a single application of Se was supplied to the plants at the beginning of pollen development. Two olive cultivars (Arbequina and Maurino) were used in three different experiments in which Se enrichment was carried out through (i) endo-xylematic drip injection, (ii) foliar spray, (iii) soil application. The pollen performance was assessed at anthesis. The results showed that Se enrichment in non-stressed plants induced a higher rate of pollen viability and germination, but it did not always stimulate their reproductive performance. Different responses were obtained in drought stressed plants, in which Se induced pollen germination, obtaining a performance similar to non-stressed plants. The ROS detection by a quantitative method, applied on hydrated pollen, verified the results just discussed

The Influence of Light on Olive (Olea europaea L.) Fruit Development Is Cultivar Dependent

In olive, the response to environmental conditions, such as light availability, is under genetic control and requires a combination of biochemical and physiological events. We investigated the effect of irradiance in fruit development in two Italian cultivars, Leccino and Frantoio. Morphological and cyto-histological analyses, as well as water and oil content determination, were carried out in fruits exposed to a different light regime (named as light and shade fruits). Results demonstrated that the influence of light availability on fruit development depends on the cultivar. In Leccino, the fresh and the dry weight, the percentage of dry matter, the kernel and fruit diameter, the mesocarp thickness and the mesocarp cell size were higher in the light exposed fruits than in the ones grown in the shade. In Frantoio, differences between light and shade fruits were observed only at 140 DAF (Days After Flowering) and only in the kernel and fruit diameter and in the dry and fresh weight, which were higher in the light exposed fruits. Leccino, therefore, showed a greater sensitivity to the light availability. This may be related to the observed delay in the endocarp lignification as compared to the Frantoio cultivar. In each cultivar, moreover, shade and light fruits did not show differences in the timing of cell differentiation. Finally, the investigation of oil storage carried out in cyto-histological studies demonstrated that differences in oil content between fruit subjected to different light regimes correlated with the number of oil containing cells, rather than the oil content per cell. A different behaviour was observed in the two cultivars: in Leccino, the mesocarp cell size was almost twice of Frantoio, while oil drops were only 30% larger; therefore, the percentage of cell volume occupied by the oil drops was lower in Leccino than in Frantoio. The chemical analysis confirmed this observation

Melatonin MT1 receptors as a target for the psychopharmacology of bipolar disorder: a translational study

The treatment of bipolar disorder (BD) still remains a challenge. Melatonin (MLT), acting through its two receptors MT1 and MT2, plays a key role in regulating circadian rhythms which are dysfunctional in BD. Using a translational approach, we examined the implication and potential of MT1 receptors in the pathophysiology and psychopharmacology of BD. We employed a murine model of the manic phase of BD (Clock mutant (ClockΔ19) mice) to study the activation of MT1 receptors by UCM871, a selective partial agonist, in behavioral pharmacology tests and in-vivo electrophysiology. We then performed a high-resolution Nuclear Magnetic Resonance study on isolated membranes to characterize the molecular mechanism of interaction of UCM871. Finally, in a cohort of BD patients, we investigated the link between clinical measures of BD and genetic variants located in the MT1 receptor and CLOCK genes. We demonstrated that: 1) UCM871 can revert behavioral and electrophysiological abnormalities of ClockΔ19 mice; 2) UCM871 promotes the activation state of MT1 receptors; 3) there is a significant association between the number of severe manic episodes and MLT levels, depending on the genetic configuration of the MT1 rs2165666 variant. Overall, this work lends support to the potentiality of MT1 receptors as target for the treatment of BD

Productive and vegetative behavior of olive cultivars in super high-density olive grove

In recent years, there has been an increase in interest in super high-density (SHD) olive (Olea europaea L.) groves because they offer early entry into production, increased productivity and the possibility of using modified mechanical vine harvesters. This study was carried out in a young SHD olive grove to examine vegetative, histo-anatomical and productive characteristics and oil quality of the Spanish Arbequina and Italian Maurino and Leccino cultivars, characterized by low, low-to-medium and high vigor, respectively. Arbequina had low vigor and limited development in height and width, as well as a high leaf/wood ratio. Maurino had a canopy volume similar to that of Arbequina and, despite a great tendency to grow in height, had low vigor, a rather compact vegetative habitus, but good lighting in the canopy and high production efficiency. In Maurino, a greater palisade parenchyma height and a larger exposed lateral surface area of the palisade parenchyma cells were observed. In the fourth year after planting, fruit production of Arbequina was about 30 % less than Leccino and Maurino. The oil content on a dry weight basis was slightly higher in Arbequina and Maurino than in Leccino. Oil quality was good for all cultivars

Herbicide Uptake and Regrowth Ability of Tall Fescue and Orchardgrass in S-Metolachlor-Contaminated Leachates from Sand Pot Experiment

The ability of tall fescue (Festuca arundinacea L.) and orchardgrass (Dactylis glomerata L.), to remediate leachates polluted with S-metolachlor (SMR) has been assessed in static hydroponic cultures. Different SMR concentrations (0.25, 1.00, and 2.00 mg L−1) were applied in the growth media to test the capacity of the two grasses to tolerate and uptake this herbicide, and to regrowth after mowing. S-metolachlor did not severely affect the dry weight aerial biomass of D. glomerata and F. arundinacea, which were reduced by 5% and 10%, respectively, when compared to the untreated control, regardless of the SMR concentrations in the leachate. The regrowth ability of aerial biomass after mowing was reduced at the different SMR concentrations, according to a dose–response model. The SMR concentrations, which reduced the regrowth ability of F. arundinacea and D. glomerata of 10% and 30%, were found to be EC10 (Effective Concentration) of 0.21 and 0.38 mg L−1 and EC30 of 0.45 and 0.74 mg L−1, respectively. These values could be assumed as the SMR concentrations that were well tolerated by both the species, without compromising their aerial biomass regrowth. Finally, tall fescue was found to be more effective and faster than orchardgrass in decreasing the SMR in the leachate and, therefore, this species should be preferred to be used in the vegetative buffer strips (VBS)

The First Molecular Identification of an Olive Collection Applying Standard Simple Sequence Repeats and Novel Expressed Sequence Tag Markers

Germplasm collections of tree crop species represent fundamental tools for conservation of diversity and key steps for its characterization and evaluation. For the olive tree, several collections were created all over the world, but only few of them have been fully characterized and molecularly identified. The olive collection of Perugia University (UNIPG), established in the years’ 60, represents one of the first attempts to gather and safeguard olive diversity, keeping together cultivars from different countries. In the present study, a set of 370 olive trees previously uncharacterized was screened with 10 standard simple sequence repeats (SSRs) and nine new EST-SSR markers, to correctly and thoroughly identify all genotypes, verify their representativeness of the entire cultivated olive variation, and validate the effectiveness of new markers in comparison to standard genotyping tools. The SSR analysis revealed the presence of 59 genotypes, corresponding to 72 well known cultivars, 13 of them resulting exclusively present in this collection. The new EST-SSRs have shown values of diversity parameters quite similar to those of best standard SSRs. When compared to hundreds of Mediterranean cultivars, the UNIPG olive accessions were splitted into the three main populations (East, Center and West Mediterranean), confirming that the collection has a good representativeness of the entire olive variability. Furthermore, Bayesian analysis, performed on the 59 genotypes of the collection by the use of both sets of markers, have demonstrated their splitting into four clusters, with a well balanced membership obtained by EST respect to standard SSRs. The new OLEST (Olea expressed sequence tags) SSR markers resulted as effective as the best standard markers. The information obtained from this study represents a high valuable tool for ex situ conservation and management of olive genetic resources, useful to build a common database from worldwide olive cultivar collections, also based on recently developed markers

Carbon footprint of an olive tree grove

In recent years, the role of Life Cycle Assessment (LCA) of products and processes has increased in importance, since it is the best technique to quantify environmental impacts associated with a process or product. The study was carried out in an olive grove located in Central Italy with “Leccino” cultivar. The olive grove was established in year 2000 with a planting distance of 5.5 × 5.5 m, trained to the vase system, under dry conditions. The same methodology used for forestry trees (“model tree”) was adopted to estimate the biomass and the respective carbon stock of the belowground and above-ground parts of the olive tree as well as quantification of the non-permanent components periodically removed, i.e. fruits and prunings. The environmental impacts associated with management processes were evaluated according to LCA standards (UNI EN ISO 14040 and 14044). In relation to the impact on climate change, the CO2 sources and sinks were calculated in order to obtain the net carbon stock of the olive grove. These data were confirmed by experimental measurement of the tree biomass in three representative olive trees. The treatments and processes that had the greatest impact were identified and the individual phases and materials were then analysed in order to propose possible actions for reducing emissions throughout the entire olive grove life cycle. Removals and emissions were compared on a time scale, in order to identify the break-even point. The results allow to assess the carbon footprint of an olive grove, at different stages of its life cycle, as a support tool for creating a sustainable production chain in the olive sector. The paper proposes a methodological approach that can be adopted also in other olive groves with different horticultural management models