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Biostimulants contribute to the physiological growth of plants by enhancing the quality characteristics of fruit without harming the environment. In addition, biostimulants applied to plants strengthen nutritional efficiency, abiotic stress tolerance, and fruit biochemical traits. We investigated the effectiveness of specific organic biostimulants. Five treatments were tested: (1) control (H2O, no biostimulants); (2) Magnablue + Keyplex 350 (Mgl + Kpl350); (3) Cropobiolife + Keyplex 120 (Cpl + Kpl120); (4) Keyplex 120 (Kpl120); and (5) Magnablue + Cropobiolife + Keyplex 120 (Mgl + Cpl + Kpl120) on the mineral uptake and physiology in black chokeberry (Aronia) plants, as well as the quality of their berries. The different treatments were applied to three-year-old chokeberry plants, and the experimental process in the field lasted from May to September 2022 until the harvest of ripe fruits. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) revealed that the fifth treatment significantly increased concentrations of P, Ca, and K. Additionally, the fifth treatment enhanced photochemical efficiency (Fv/Fm), water-splitting efficiency (Fv/Fo) in PSII, and the performance index (PI) of both PSI and PSII in chokeberry leaves. Improvements in photosynthesis, such as CO2 assimilation (A), transpiration (E), and water-use efficiency (A/E), were also noted under biostimulant applications. Upon harvesting the ripe fruits, part of them was placed at room temperature at 25 °C, while the rest were stored at 4 °C, RH 90% for 7 days. The cultivation with biostimulants had beneficial effects on the maintenance of flesh consistency, ascorbic acid concentration, and weight of berries at 4 and 25 °C, especially in the 5th treatment. Moreover, the total antioxidant capacity, anthocyanin concentration, and total phenols of the berries were notably higher in the third and fifth treatments compared to the control. These data suggest that selecting appropriate biostimulants can enhance plant yield and fruit quality by potentially activating secondary metabolite pathways. [ABSTRACT FROM AUTHOR]

Mentha spicata L., Origanum dictamnus L., and Origanum onites L. are aromatic plants that produce very important essential oils. They are considered model plants with beneficial health properties due to their antioxidant content. Enhancing the yield while maintaining the quality of essential oil is of significant commercial importance. Salinization and drought cause various effects on the yield and quality of the bioactive constituents in essential oil. By assessing the response of these plants and their secondary metabolites accumulation to different salt stress and irrigation levels, this study aims to gain insights into how plants adapt to and cope with salinity and drought. A pot experiment was conducted in the spring of 2020 to assess the effect of salinity and drought stress on the growth and essential oils content of the three aromatic plant species mentioned above. The soil mixture used was perlite and peat in a ratio of 1:1:6, while four salinity treatments (25, 50, 100, and 150 mΜ NaCl) and two levels of irrigation were applied (100% and 50%). Salinity significantly affects total chlorophyll concentration especially in higher concentrations (100 and 150 mM) in M. spicata plants, especially under 50% soil water irrigation. Under the same conditions, M. spicata contained the higher proline concentration, which was significantly greater than that in O. dictamnus and O. onites. Similar variations of malondialdehyde and hydrogen hyperoxide were revealed among the three species, with significantly higher values in M. spicata when subjected to both excess salinity and drought conditions. The major compounds identified in M. spicata were carvone, in O. dictamnus carvacrol, and p-cymene and in O. onites carvacrol. It is important to highlight that O. onites had the highest concentration of essential oil, and that the concentration increased with the increase of NaCl. This suggests that the presence of NaCl in the soil may have a stimulating effect on the production of essential oil in O. onites. However, it is plausible that the stress caused by NaCl triggers a physiological response in O. onites, leading to increased production of essential oil. This could be a protective mechanism to enhance the plant's resistance to the stressor. Overall, O. onites and O. dictamnus appeared to be more resistant to these stress conditions than M. spicata, since they maintained their growth and essential oil quality indicators at higher levels. These two species possess mechanisms that prevent or minimize lipid peroxidation, thus protecting their cell membranes and maintaining their ultrastructure integrity. [ABSTRACT FROM AUTHOR]

Since drought stress is one of the key risks for the future of agriculture, exploring the molecular mechanisms of photosynthetic responses to water deficit stress is, therefore, fundamental. By using chlorophyll fluorescence imaging analysis, we evaluated the responses of photosystem II (PSII) photochemistry in young and mature leaves of Arabidopsis thaliana Col-0 (cv Columbia-0) at the onset of water deficit stress (OnWDS) and under mild water deficit stress (MiWDS) and moderate water deficit stress (MoWDS). Moreover, we tried to illuminate the underlying mechanisms in the differential response of PSII in young and mature leaves to water deficit stress in the model plant A. thaliana. Water deficit stress induced a hormetic dose response of PSII function in both leaf types. A U-shaped biphasic response curve of the effective quantum yield of PSII photochemistry (ΦPSII) in A. thaliana young and mature leaves was observed, with an inhibition at MiWDS that was followed by an increase in ΦPSII at MoWDS. Young leaves exhibited lower oxidative stress, evaluated by malondialdehyde (MDA), and higher levels of anthocyanin content compared to mature leaves under both MiWDS (+16%) and MoWDS (+20%). The higher ΦPSII of young leaves resulted in a decreased quantum yield of non-regulated energy loss in PSII (ΦNO), under both MiWDS (−13%) and MoWDS (−19%), compared to mature leaves. Since ΦNO represents singlet-excited oxygen (1O2) generation, this decrease resulted in lower excess excitation energy at PSII, in young leaves under both MiWDS (−10%) and MoWDS (−23%), compared to mature leaves. The hormetic response of PSII function in both young and mature leaves is suggested to be triggered, under MiWDS, by the intensified reactive oxygen species (ROS) generation, which is considered to be beneficial for activating stress defense responses. This stress defense response that was induced at MiWDS triggered an acclimation response in A. thaliana young leaves and provided tolerance to PSII when water deficit stress became more severe (MoWDS). We concluded that the hormesis responses of PSII in A. thaliana under water deficit stress are regulated by the leaf developmental stage that modulates anthocyanin accumulation in a stress-dependent dose. [ABSTRACT FROM AUTHOR]

Olive-mill wastewater (OMW) constitutes a major agricultural waste stream for which disposal is associated with significant environmental repercussions. No data are available on the effects of biotreated OMW and of the protective role of exogenously provided proline on plant physiology. In the present study, OMW was administered, either raw or previously treated by the white-rot fungus Pleurotus ostreatus, with or without proline amendment, to lettuce plants growing in sterilized sand. Biotreated OMW and proline addition resulted in significant moderation of OMW adverse effects on plant biomass production and ascorbic acid content, while their synergistic action alleviated the severe negative impact on net photosynthetic rate, water use efficiency and photosynthetic activity (Fv/Fo) invoked by the effluent. Moreover, biotreated OMW supplemented with proline, moderated the decrease in chlorophylls exerted by raw OMW, but it did not contribute at restoring carotenoids content. Restoration of plant transpiration was complete when biotreated OMW was used (with or without proline); proline alone mitigated the negative impact of OMW on photosynthetic efficiency (Fv/Fm and Fv′/Fm′). It seems that key photosynthetic parameters could be exploited as suitable evaluators of wastewater-induced plant toxicity, while plant fertigation with biotreated and/or supplemented OMW could be an interesting prospect in valorizing this effluent. [ABSTRACT FROM PUBLISHER]

The effect of Cu toxicity on photosynthetic function, chlorophyll and Ca2+ content of Cu-tolerant Silene compacta plants grown in nutrient solution was studied. Since, in plants grown under 8 µM Cu, the chlorophyll and Ca2+ concentration as well as the photosystem II (PSII) photochemistry were increased, compared to the control, the development of an adaptive mechanism of the Cu-tolerant ecotype of S. compacta to 8 µM Cu is suggested. Increased Cu tolerance of the S. compacta ecotype reflects modulation of the photosynthetic apparatus to optimize photosynthesis. However, exposure of plants to 160 µM Cu resulted in a marked increase of the fraction of closed PSII centres and decreased quantum yield of PSII electron transport (ΦPSII) which was accompanied by a significant decline of relative quantum yield for O2 evolution (Aox/Apt). The concentration of chlorophyll and Ca2+ in leaves also decreased significantly under 160 µM Cu treatment. Photochemical quenching (qp) displayed a reduction as a result of perturbation of the photosynthetic electron transfer chain, while non-photochemical quenching (qN) increased. High Cu treatment reduced photosynthetic productivity of S. compacta plants which can be attributed, in part, to perturbation of photosynthetic process and photosynthetic pigments as well as to Ca2+ loss. [ABSTRACT FROM AUTHOR]

The dynamics of maturation index, water and oil concentrations, and total phenols in olive fruit, together with fatty acids and total phenols content in olive oil, was studied as a function of time after flowering for super-high-density 'Arbequina', 'Arbosana' and 'Koroneiki' using data collected in three seasons. Oil concentration increased linearly from the middle of August until reaching a plateau by the end of November for all three cultivars, with 'Koroneiki' (45.7 g/100 g) and 'Arbosana' (45.4 g/100 g) showing higher maximum oil concentration than 'Arbequina' (41.8 g/100 g). While total phenols in the fruit decreased linearly during the harvest for all three cultivars, phenolics in oil peaked at 180 days after flowering (400 mg/kg) for 'Arbequina' and at 160 days after flowering (600 mg/kg) for 'Koroneiki'. For 'Arbosana', total phenols in oil decreased linearly with a maximum of 400 mg/kg for early harvest oils. Fatty acid dynamics was largely affected by genotype, with 'Arbequina' displaying the largest variation in fatty acid concentrations along the season. 'Koroneiki' presented the highest values of oleic acid (73.0–77.1%), followed by 'Arbosana' (70.2–72.4%) and 'Arbequina' (64.4–74.0%). Results presented here are useful for growers to make planting and harvesting decisions, for producers to understand the differences in oil made from the most common super-high-density cultivars during the harvest seasons, and for regulators to consider legal standards for authentic olive oil. [ABSTRACT FROM AUTHOR]

Global climate change, especially global warming, is affecting olive production efficiency as well as its product quality. The size and water content of fruit varies depending on the olive fruit yield along with the region, climate, and geographical position as well as agricultural applications. Anthropogenic activities also affect its ecology to a great extent. The plant prefers areas with mild winters and short rainy seasons but is facing long and dry summers, sunny habitats, well drained dry, poor, loamy, clayey-loamy, slightly calcareous, pebbly and nutrient-rich soils, with a pH around 6–8. It is resistant to drought but suffers much from harsh winters and air pollutants, which affect its production. Although the olive plant tolerates temperatures between −7 °C to 40 °C, the optimum temperature demanded for growth, development, and fruit yield is 15–25 °C. The annual precipitation demand lies between 700–850 mm. An important part of the composition of its fruit consists of water and oil or the "liquid gold". Main ingredients are additionally fat-soluble vitamins, minerals, organic sugars, and phenolics. Phenolic substances are responsible for many beneficial health effects as well as the taste and aroma of olive fruit. Oleuropein stands out due to its inhibition of oxidation of low density lipoproteins and its hypoglycemic and cholesterolemic effects. It is also a component that protects the olive tree against various parasites and diseases, one of the reasons why olive is recorded as the "immortal tree". Olive trees are cultivated in different regions of Turkey. A series of changes occur in morphological, physiological, and biochemical features to overcome different types of stress. In this review, information about the botanical aspects, eco-physiology, and pharmaceutical features of the oil, fruit, and leaves has been evaluated. [ABSTRACT FROM AUTHOR]