Search

Background: A modified version of the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method has been tested for quantifying six active compounds of pharmaceuticals (PhACs), i.e., two different antibiotics, two anti-inflammatories, one antifungal, and one anti-depressant, extracted from roots, leaves and stems, pulp, pits, and oil obtained from olive trees. The different matrices have been polluted with all contaminants at 25, 50, and 250 µg L−1 and the recoveries were determined by liquid chromatography tandem–mass spectrometry. The validation of the method has been carried out by determining linearity, recovery, precision, limits of detection (LODs), and limits of quantification (LOQs) values. A matrix-matched calibration for each matrix has been adopted in order to avoid the matrix effect at the aforementioned levels of fortification. Results: The recoveries of PhACs from the different matrices were always above 70% and the relative standard deviation (RSD) always ≤ 20%, conditions required for the validation of the method. The LOD and LOQ values were always lower than 25 µg L−1, i.e., always lower than the minimum concentration used in the experiment; therefore, the method can be validated at 25, 50, and 250 µg L−1. Conclusions: This method can represent a valid alternative to the traditional extraction methods to quantify pharmaceuticals extracted also from fatty matrices. [ABSTRACT FROM AUTHOR]

Aims: The conventional management adopted in many Mediterranean olive orchards makes them more vulnerable to climate change and attacks by pathogens, due to the decreased chemical plant defenses. In this scenario, a metabolomic analysis was carried out on the xylem sap (Xsap) of olive plants (Olea europaea L.) grown in the Salento peninsula (Italy). Methods: Trials were carried out in two olive groves, one organically and one conventionally managed (controls), successively both converted to sustainable management (i.e. frequent light pruning, soil and foliar fertilization, cover crops). The Xsap was extracted from the shoots of olive plants using a Scholander pressure chamber pressurized with N2 and gas chromatography-mass spectrometry metabolite profiling was performed in the Xsap. Results: An untargeted gas chromatography mass spectrometry (GC-MS) based metabolomic analysis of primary metabolites (including underivatized volatiles) of the Xsap revealed relative abundances of 153 identified metabolites and 336 unknown features across the 12 samples from four groups of samples. Among them, more than half were involved in the primary metabolism. Many of the compounds with increased levels under sustainable management (such as amino acids, soluble sugars, sugar alcohols) have a well-known role as osmoprotectants or are involved in plant defense, growth and development during stress or recovery stages. Conclusions: Sustainable management in olive groves can increase the ability of plants to overcome environmental stressors and enhance ecosystem balance. [ABSTRACT FROM AUTHOR]

A field study and an experiment under controlled conditions using pressure-flux relationships were conducted to compare the stem and whole-plant conductance in olive ( Olea europaea) and kiwifruit ( Actinidia deliciosa) species. Anatomical observations were also made on one-year-old stem to determine the conductive area of vessels ( A) and the total xylem area ( A). Results show that A of kiwifruit twigs was ~2.5-fold of that in olive twigs, and the hydraulically weighted mean diameter was up to threefold that of the olive ones. One-year-old olive twigs had lower hydraulic conductivity ( k) than the kiwifruit, while values of leaf-specific conductivity (i.e. k normalised per unit leaf area) were higher than the kiwifruit (i.e. ~49 and 29 × 10 kg m s MPa, respectively). In the field experiment, the flux of sap (heat balance method) and differences in water potential through the soil-plant system (Δ P) were used for both species to calculate the whole-plant conductance that was normalised per unit leaf area (leaf-specific whole-plant conductance, K). Values of K are attributable to the combined effect of the Δ P and anatomical features of conduits. Olive species showed a larger Δ P (2.4 MPa at midday) than the kiwifruit (0.5 MPa) which contributed to lower K in Olea than the Actinidia plants. This information, combined with vessel density data, contributes to explain differences amidst olive and kiwifruit species, in terms of susceptibility to some drought-related hydraulic impairments induced by the Mediterranean environment. [ABSTRACT FROM AUTHOR]

The aim of the present work was to evaluate the effects of regulated deficit irrigation (RDI) applied in the post-harvest stage of peach trees. The 3-year trial was carried out in Italy (N 40°20′, E 16°48′) on mature peach plants (cv “Springcrest”) trained to transverse Y. From bud break to harvest, irrigation was carried out by applying 100% ETc, while from harvest to early autumn, plants were separated into three groups and subjected to different irrigation treatments (100, 57 and 34% ETc). The decrease in soil water content caused a reduction in the values of tissue water potential and gas exchange both in 57% ETc and 34% ETc treatments. RDI determined the reduction in the growth of waterspouts and lateral shoots but did not influence the growth of fruiting shoots. During the trial, no significant reductions in crop yield and quality were observed in the 57% ETc treatment, whereas about 1,100, 1,800 and 2,500 m3 ha−1 of water were saved in the first, the second and the third year, respectively. In the second year of the trial, the use of RDI in the post-harvest stage determined carbohydrate and nitrogen accumulation in roots, branches, shoots and floral buds. The results demonstrate that, under scarce water supply conditions, a clear benefit can be obtained through the use of RDI during the post-harvest stage. This confirms the possibility to reduce the irrigation water by applying RDI during phenological stages less sensitive to water deficit without negatively affecting peach growth and yield. [ABSTRACT FROM AUTHOR]

The effects of water stress on water potential components, tissue water content, mean elastic modulus and the osmoregulation capacity of olive ( Olea europaea L. cv. Coratina) leaves was determined. Artificial rehydration of olive leaf tissues altered the P-V relationships so that a plateau phenomenon occurred. Points in the P-V curve in the region affected by the plateau, generally up to -0.5 MPa, were corrected for all the samples analyzed. In the corrected P-V relationship, an osmotic adjustment was found in drought-stressed leaf tissues. Osmotic potentials at full turgor (Ψ0 (sat)) and osmotic potential at turgor-loss (Ψ0 (TVT)) decreased from -2.06±0.01 MPa and -3.07±0.16 MPa in controls to -2.81±0.03 MPa and -3.85±0.12 MPa in most stressed plants. Osmotic adjustment values obtained from the P-V curves agreed with those obtained using an osmometer. An active osmotic adjustment of 1.42 MPa was also observed in 1–4 mm- diameter roots. Mannitol is the main carbohydrate involved in osmotic potential decrease in all treatments. The maximum elastic modulus increased from 11.6±0.95 MPa in the controls to 18.6±0.61 MPa in the most stressed plants. [ABSTRACT FROM AUTHOR]