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A comparative study was conducted to evaluate the effect of location on the chemical composition and quality of monovarietal virgin olive oils obtained from the Chétoui cultivar in relation to the fruit ripening stages. Three sites representative of two Tunisian olive growing regions were examined, Selten (region I (RI): original site of plantation of Chétoui variety in the north of the country), Ousletia and Jelma (region II (RII): in the central part of the country away from the original plantation site). In this study, Chétoui olive cultivar was found to have different responses to environmental conditions. Chétoui olive oils showed lower values in phenol and o-diphenol contents and were less stable to oxidation (weaker oxidative stability and antioxidant activity levels) when the olive trees were cultivated away from the original plantation site. These Chétoui olive oils are also characterized by decreased oil content and higher values of quality parameters such as free acidity, peroxide value and UV absorbance due probably to the drought during the flowering and olive ripening periods. Furthermore, many analytical parameters, i.e., chlorophyll pigments, carotenoids, oleic acid contents, total phenol and o-diphenol amounts, oxidative stability, antioxidative capacity and quality parameters showed nearly the same changes during fruit ripening but in different degrees depending on the site of the plantation.

The use of plant growth‐promoting rhizobacteria (PGPR) in agriculture is one of the most promising approaches to improve plants' growth under salt stress and to support sustainable agriculture under climate change. In this context, our goal was to grow and enhance quinoa growth using native rhizobacteria that can withstand salt stress. To achieve this objective, we isolated rhizobacteria from three saline localities in a semi‐arid region in Tunisia, which are characterized by different halophyte species and tested their plant growth‐promoting (PGP) activities. Then, we inoculated quinoa seedlings cultivated on 300 mM NaCl with the three most efficient rhizobacteria. A positive effect of the three‐salt tolerant rhizobacteria on the growth of quinoa under salinity was observed. In fact, the results of principal component analysis indicated that the inoculation of quinoa by salt‐tolerant PGPR under high salinity had a prominent beneficial effect on various growth and physiological parameters of stressed plant, such as the biomass production, the roots length, the secondary roots number, proline content and photosynthesis activities. Three rhizobacteria were utilized in this investigation, and the molecular identification revealed that strain 1 is related to the Bacillus inaquosorum species, strain 2 to Bacillus thuringiensis species and strain 3 to Bacillus proteolyticus species. We can conclude that the saline soil, especially the halophytic rhizosphere, is a potential source of salt‐tolerant plant growth‐promoting rhizobacteria (ST‐PGPR), which stimulate the growth of quinoa and improve its tolerance to salinity. [ABSTRACT FROM AUTHOR]

Most crop species are cultivated in nutrient-deficient soils, in combination with other challenging constraints that are exacerbated by the current climate changes. The significance of micronutrient shortage in stress management is often underappreciated, although their deficiency restricts both plant growth and resistance to abiotic stresses and diseases. While the application of nutrients to growing plants is a potential strategy to improve plant resistance to abiotic stresses, seed nutrient status may also play a role in crop stress tolerance as a storage and accumulation site of nutrients. To avoid hidden hunger problems, developing countries need to increase domestic cereal production, enhance their resilience to extreme weather events, and improve their nutritional status and quality. Here, we analyze the accumulated knowledge about the effects of nutri-priming in cereal crop species with a focus on mechanisms of application and stress tolerance, keeping in mind the risk of crop damage mostly caused by global climate change, which is driving an alarming increase in the frequency and intensity of abiotic stresses. We also propose new approaches to food production, which may be promising solutions for global warming, emerging diseases, and geopolitical conflicts recognized as major drivers of food insecurity. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether silicon (Si) supply was able to alleviate the harmful effects caused by salinity stress on sorghum-sudangrass (Sorghum bicolor × Sorghum sudanense), a species of grass raised for forage and grain. Plants were grown in the presence or absence of 150 mM NaCl, supplemented or not with Si (0.5 mM Si). Biomass production, water and mineral status, photosynthetic pigment contents, and gas exchange parameters were investigated. Special focus was accorded to evaluating the PSI and PSII. Salinity stress significantly reduced plant growth and tissue hydration, and led to a significant decrease in all other studied parameters. Si supply enhanced whole plant biomass production by 50%, improved water status, decreased Na+ and Cl− accumulation, and even restored chlorophyll a , chlorophyll b , and carotenoid contents. Interestingly, both photosystem activities (PSI and PSII) were enhanced with Si addition. However, a more pronounced enhancement was noted in PSI compared with PSII, with a greater oxidation state upon Si supply. Our findings confirm that Si mitigated the adverse effects of salinity on sorghum-sudangrass throughout adverse approaches. Application of Si in sorghum appears to be an efficient key solution for managing salt-damaging effects on plants. Soil salinity is a worldwide environmental constraint that affects crops growth and productivity. Silicon supply has been observed to ameliorate crops growth under various stresses. In this study, silicon supply was found to significantly enhance the decline the growth of sorghum-sudangrass (Sorghum bicolor × Sorghum sudanense) under salinity stress, increasing productivity and enhancing plants vigour throughout many aspects. Hence, silicon seems to be a promising approach to strengthen agriculture yield. [ABSTRACT FROM AUTHOR]

The current investigation aims to underline the impact of salicylic acid or calcium chloride seed pre-treatments on mineral status and oxidative stress markers, namely levels of electrolyte leakage (EL) and lipid peroxidation levels, measured as thiobarbituric reactive substances (TBARS), and the activity of some antioxidant enzymes in roots and leaves of plants in two barley species grown under various salt treatments. Overall, our results revealed that salinity inhibits essential nutrient absorption such as iron, calcium, magnesium and potassium and stimulates the absorption of sodium. Also, this environmental constraint induced oxidative stress in plants in comparison with the control conditions. This state of oxidative stress is reflected by an increase in TBARS content as well as the stimulation of EL values. In addition, salinity induced disturbances in the activity of antioxidant enzymes, which were mainly dependent on the applied salt concentration and the species. In addition, Hordeum marinum maintained high antioxidant enzyme activity and low levels of oxidative stress parameters, which reinforces its salt-tolerant character. Importantly, salicylic acid or calcium chloride seed priming alleviated the mineral imbalance and the oxidative damage induced by salinity. Moreover, seed priming improves iron, calcium magnesium and potassium content and limitsthe accumulation of sodium. Also, both treatments not only decrease TBARS levels and limit EL, but they also stimulate the antioxidant enzyme activities in the leaves and roots of the stressed plants as compared with stressed plants grown from non-primed seeds. Interestingly, the beneficial effects of the mentioned treatments were more notable on Hordeum vulgare species. [ABSTRACT FROM AUTHOR]

The current study aimed to evaluate Tunisian Tamarix africana Poir biological activities. In this study, novel biological activities of the shoot extracts related to their phenolics investigated. Secondary metabolite contents, antioxidant, anti-inflammatory and cytotoxic activities of four extracts (hexane, dichloromethane, methanol and water) were investigated. Antioxidant activities were assessed via in vitro and ex vivo assays. Besides, anticancer activity was investigated against human lung carcinoma (A-549) and colon adenocarcinoma (DLD-1) cells. The anti-inflammatory ability was evaluated via inhibition of LPS-induced NO production in RAW 264.7 macrophage cell lines. Methanol and water extracts displayed the highest antioxidant (IC50 = 3.3 and 4.3 µg/mL respectively), which are correlated activities correlated with phenolic contents. Hexane extract exhibited an important anti-inflammatory effect inhibiting NO ability by 100% at 80 µg/mL. Besides, T. africana extracts were found to be active against A-549 lung carcinoma cells with IC50 values ranging from 20 to 34 µg/mL. These results suggested that T. africana is considered as a potential source of readily accessible natural molecules with a promising effect on human health and diseases. [ABSTRACT FROM AUTHOR]