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In this study, the biosorption ability of various potentially toxic elements from phosphate-processing effluent (PPE) using the indigenous bacterium Serratia rubidaea NCTC12971 immobilized in Ca-alginate beads was investigated. The experimental data analyzed by the Langmuir isotherm revealed that the optimum dose of 2 g·100 ml

To investigate the effects of salinity stress on durum wheat cultivars at the critical stages of germination and seedling establishment under salinity stress, a study was conducted on eight durum wheat cultivars (Karim, Khiar, Inrat100, Maali, Monastir, Portodur, Razeg, and Salim) subjected to an increasing salinity concentration by using sodium chloride (NaC) (0, 2, 4, 6, and 10 g L−1). Germination and seedling physiological parameters were measured and thoroughly analyzed. Salinity stress significantly decreased germination capacity (GC), germination rate (GR), final germination capacity (FGC), germination index (GI), mean daily germination (MDG), and velocity coefficient (Vc), whereas mean germination time (MGT) and the stress index (SI) increased. Plantlet growth and initial vigor (IV) were also significantly hampered. Regarding all these traits, the cultivars’ differences were revealed: Karim and Salim were the least affected, whereas Razeg and Maali were the most affected, and the other cultivars occupied an intermediate position. Depending on cultivar, salinity stress decreased the germination capacity and delayed its initiation. At low salinity stress (2–4 g L−1 NaCl), the osmotic effect (OE) was the main cause of germination inhibition, whereas at high salinity stress (6–10 g L−1 NaCl), the toxic effect (TE) dominated and irreversibly inhibited the germination process. The initial vigor and the stress index that clearly discriminate among the studied cultivars are useful traits for screening tolerant genotypes. Otherwise, durum wheat showed a higher plasticity with salinity at the germination stage, allowing it to develop better tolerance at this stage, as compared to early stage plantlet growth.

Organic extracts of aerial parts from Tricholaena teneriffae L. (Poaceae), a wild grass largely distributed in the arid regions, were screened for their phenolic compounds, antioxidant and antibacterial activities. LC-ESI-MS analysis resulted in the identification of 21 compounds distributed into 8 phenolic acids and 13 flavonoids. Phenolic acids represented 80% of the identified compounds in alcoholic extracts. In fact, quinic acid was the major compound (11.68 mg/g) followed by 4,5-di-O-caffeoylquinic acid (3.72 mg/g) measured in the methanol extract. The methanol extract presented the highest total antioxidant capacity (617 mg AAE/g) followed by the ethyl acetate extract (437 mg AAE/g). In addition, these extracts also showed the highest DPPH• scavenging activity as evidenced by the lowest IC50 values (IC50 = 0.10–0.11 mg/ml). The ferric reducing power was also measured and the better results (EC0.5 = 0.25–0.32 mg/ml) were obtained for ethyl acetate and ethanol extracts. The methanol extract (3 mg/well) was found to be the most potent (11–16 mm) againt most tested strains and Micrococcus luteus was the most vulnerable bacteria with MIC value of 2.5 mg/ml.

Trace metal pollution is increasing worldwide due to human activities. In this study, we investigated the physiological and biochemical effects of heavy metals on henna plants (Lawsonia inermis L.) grown in oases situated at various distances from an industrial complex in arid southern Tunisia. Our results showed that leaves had higher mean Zn and Cu concentrations than roots, while the reverse was true for Pb and Cd. Such metal immobilization in root cells is related to an exclusion strategy. The biological concentration factor (BCF) of Cu was > 1 at all studied sites, indicating the potential of henna plants to accumulate Cu from the soil. Heavy metals affected various physiological parameters of henna, including water status, macronutrient content, and photosynthetic activity, and increased the rate of hydrogen peroxide (H2O2) production and lipid peroxidation in leaves and roots, indicating oxidative stress. Deleterious heavy metal effects induced biochemical mechanisms in henna plants by accumulating proline and soluble sugars and activated the antioxidant system by enhancing the activities of superoxide dismutase, catalase, and glutathione peroxidase. The magnitude of accumulation and activation was proportional to the concentration of heavy metals in the plant tissues. The stimulation of enzymatic and non-enzymatic antioxidant systems reflects the ability of henna plants to survive in highly polluted environments.

This paper presents analysis, design, and optimization of a high-power permanent-magnet synchronous generator (PMSG). This generator is introduced in a large-scale wind turbine which can be used in a big wind farm. This generator is used in gearless configuration. The work focuses on the geometric sizing and the finite element analysis (FEA) of the PMSG. FEA is a good choice for analyzing problems over complicated domains. The flux, the electromotive force, the cogging torque, and the torque are calculated using analytical equations. Then, these parameters are obtained using finite element method (FEM) in the software FEMM and the compared with analytical results in order to validate our study. The second part presents the formulation of the optimization problem, including the optimization space, constraints, and objectives. The genetic algorithm (GA) is adopted in this design optimization in order to minimize the generator cost.

Bioremediation using microorganisms have become innovative efficient tools for detoxifying a wide variety of urban and industrial wastewaters. In this study, we investigated for the first time the ...

Predicted climate change in the Mediterranean region has raised concerns about the possible impacts on Alphagrass (Stipa tenacissima L.) steppes. To understand the vulnerability degree and acclimation capacity of S. tenacissima populations to climate warming and the CO2 mitigation potential of Alfa steppes, we measured the physiological and morphological traits in five populations across a Mediterranean rainfall range from 100 to 600 mm/year. Results showed different response patterns to the precipitation gradient. Major differences were found in the gas exchange and leaf traits in the mesic to xeric sites. Xeric populations exhibited moderate gas exchange rates together with thicker and smaller leaves (i.e., low leaf dry matter content (LDMC), and high leaf thickness (Lth). They also presented differences in several functional traits related to water economy and earlier stomatal closure with drought. Furthermore, internal water use efficiency (IWUE) and apparent carboxylation efficiency (CE) were the lowest, and dark respiration (RD) was the highest in the arid site (Sfax) due to high temperatures. The relative water content at the turgor loss point (RWCtlp) varied from 0.91 to 0.85 from mesic to xeric sites, which demonstrates a high degree of osmotic adjustment. The leaf water retention capacity by osmotic adjustment and high cell turgor with a reduction in gas exchange activity through stomatal closure promote to S. tenacissima a sustain physiological activities under severe drought. These results suggest that S. tenacissima may have high adaptability to drought by regulating physiological activity and maintaining turgor pressure associated with suitable leaf structure. AV's work was partially funded by Projects CGL-2011-30531-CO2-02 and CGL2015- 69773-C2-2-P MINECO/FEDER by the Spanish Government, and by the Prometeo Program (FEEDBACK project, 2009/006) by the Generalitat Valenciana. CEAM is supported by the Generalitat Valenciana.

Currently, the parallel hybrid electric vehicle (PHEV) is the most common type of architecture on the hybrid vehicle market. Therefore, a PHEV can be a solution to reduce emission and fuel consumption. The main challenge in the development of HEVs is the power management between the components that ensure vehicle movement. Energy management is now highly necessary by applying a control strategy (CS) in the vehicle’s traction chain, which directly affects the PHEV emission and fuel economy. The CSs have different performances, namely the control of the different power sources operation mode and the control of the battery state of charge. For this purpose, we propose a fuzzy logic CS to optimize emissions (FLCS-em) for PHEV. To assess this approach, we compare it with the most commonly used and recent EMS, in particular the strategy to optimize fuel use (FLCS-f), the efficiency optimization strategy (FLCS-eff) and the electric assist CS (EACS), in urban and highway driving cycles. The results show that the elaborate FLCS-em, characterized by a limited number of rulers, provide significant advantage than CSs mentioned in terms of the efficiency of PHEV performance and emissions and fuel consumption minimization.

The potential of treating agro-wastes by recovering organic amendments for agricultural soils is promising for Mediterranean countries that produce olive oils. In this study, olive mill by-products...

Keystone plant species are known to provide various essential ecosystem services. The Mediterranean keystone species Stipa tenacissima improves soil functioning and facilitates the establishment of different plant species, so it is used in restoration programmes. In this paper, we aimed to predict the impacts of climate (aridity) and soil texture (sand content) on the establishment and development of S. tenacissima (number, cover and width of tussocks) and on soil properties underneath S. tenacissima tussocks. This research demonstrated a significant positive effect of S. tenacissima on LFA (landscape function analysis) indices, revealing the importance of this key species in the soil stabilization, water infiltration and nutrient cycling. Similarly, soil nutrient contents (organic carbon and total nitrogen) and enzyme activities (s-glucosidase and phosphatase) were highly improved underneath S. tenacissima compared to bare ground areas. However, increases of aridity and sand content showed strong negative effects on soil organic carbon, total nitrogen and activities of the hydrolytic enzymes both on bare ground areas and underneath S. tenacissima tussocks. Furthermore, we found that the climate is the main controller of the number of S. tenacissima tussocks, cover and width. Soil sand content influences the colonization of S. tenacissima, as it affects soil water potentials. In general, this study demonstrates the non-sustainability of S. tenacissima under a warmer and drier climate, which will negatively affect its ability to create islands of fertility in South Mediterranean grasslands.

Weeds thrive in agricultural environments. However, in certain areas of the world, they are consumed by humans as food, and they can represent a source of valuable active ingredients of ethnomedical interest. In this study, three North African parasitic plants of the Orobanchaceae family, Cistanche violacea, Orobanche crenata and Orobanche lavandulacea , normally considered as weeds, were studied to compare their biological activities. The antioxidant activity of hexane, ethyl acetate, acetone, methanol, and water extracts obtained by sequential maceration was estimated by DPPH, ABTS and FRAP assays. The metabolic profiles of aqueous extracts were studied by 1 H NMR spectroscopy. The oils extracted using hexane as solvent were analyzed by GC-FID and HPLC-DAD to characterize the fatty acid profile. The cytotoxic effect of the oil from the parasitic plants was also studied on B16F10 melanoma cancer cells. All extracts showed antioxidant activity and differences between extracts obtained using different solvents as well as for different plants have been highlighted. The highest total phenolic content was determined in O. crenata acetone extract (3.53±0.20 mmol GAE/g) and in O. lavandulacea methanol extract (2.29±0.02 mmol GAE/g). 1 H NMR spectroscopy revealed the presence of amino acids, organic acids and carbohydrates. The major fatty acids in the oils were 18:2 n -6, 16:0, 18:1 n -9, and 18:3 n -3. O. lavandulacea revealed to be a highly cytotoxic species for B16F10 melanoma cells. These data suggest that, despite the extreme climate conditions and the damage that can result, the studied desert parasitic plants can represent a novel and precious source of metabolites, with promising biological activities.

A process of continuous degradation of plant communities, due mainly to long-term overgrazing has been revealed by most ecological studies in North African arid climate. Notably, this degradation appeared across the depletion of perennial grass species exhibiting low density in the majority of range ecosystems. This study aimed to examine the phenology and the aboveground phytomass production of Stipagrostis ciliata (Desf.) De Winter accessions, a perennial grass, growing under the same environment but coming from different climates of Tunisia. Additionally, the extent of genetic variation in phenological parameters, root and shoot phytomass productivity and the correlations among these parameters were also analyzed. Significant differences in all morphological parameters of S. ciliata accessions were revealed by ANOVA test and were corroborated with significant and positive correlation indicated by Pearson’s correlation analysis. Plant diameter, biovolume, root biomass with protective sleeve and spike number exhibited significant differences and high distinctiveness between S. ciliata accessions. Tukey’s HDS tests indicated the presence of three groups of accessions. Principal component analysis (PCA) applied on a table with eight observations and 13 variables, and dispersion of S. ciliata accessions on the first two axes of PCA confirmed the presence of three groups of accessions. Trait variability in the field for the five accessions is more likely to be the result of phenotypic plasticity rather than of genetic differentiation between accessions. Overall, the characterization of S. ciliata accessions exhibited significant differences in terms of morphological and biomass productivity.

The objective of this study is to examine the viability of recycling olive industry wastes by co-composting with poultry manures, describe the evolution of the physic-chemical and microbiological composting parameters, and evaluate the maturity of the obtained compost. The co-composting process applied was a windrow composting process. A pile was prepared by mixing olive mill pomace (OMP) and olive mill solid husk (OMSH) as carbon source, poultry manure (PM) as nitrogen source, green wastes (GW) as bilking agents and olive mill wastewater (OMW) as humidifier. The mixture was prepared based on fresh weight (FW) according to the following proportions: OMP + OMSH = 51.72% FW; GW = 27.58% FW; PM = 20.68% FW and C/N ratio = 29.25. The windrow was arranged in a pile of 1.5 m height, 2 m wide and 2 m length. Results showed that during the composting process, a high microbiological activity was depicted by a quickly increase in temperature (65 °C) in 09 days. An exponential increase in the number of aerobic microorganisms in the pile with a maximum (156 × 108 CFU g−1 FM) after 09 days of incubation and a progressive decrease in the C/N ratio over time were recorded. The obtained compost had a homogeneous particle size with a fine majority fraction (70.41%

This study tests the diurnal variations of water status, leaf gas exchanges and chlorophyll fluorescence in Pistacia vera L. (P. vera L.) and Pistacia atlantica Desf. (P. atlantica Desf.) seedlings. At 40% of field capacity, diurnal variations in water uptake, relative water content (RWC) were estimated every hour between 5:00 am and 7:00 pm. The daily course of light, temperature, photosynthesis (A), stomatal conductance (gs), transpiration rate (E), intrinsic water use efficiency (A/gs), mesophyll efficiency (A/Ci), internal CO2 concentration (Ci) and chlorophyll fluorescence were measured every 3 h from 05:30 am to 7:30 pm in irrigated and stressed seedlings of the two studied species. The results showed a significant variation in all surveyed parameters over diurnal cycle. The stressed seedlings of P. atlantica exhibited considerably higher RWC, water uptake, A, gs, E, A/gs and A/Ci over diurnal cycles compared to P. vera stressed seedlings. In contrast, P. vera was more sensitive to water stress and excess light and temperature over the diurnal cycle. The midday stomatal conductance and photosynthesis decrease was more likely the result of low RWC caused by high transpiration rates, stomatal closture and photoinhibition. Photoinhibition is a protective mechanism of PSII, rather than a result of photo-damage of photosynthetic apparatus. P. atlantica revealed an important physiological feature that is maintaining photosynthesis at midday compared to P. vera. This might be due to internal regulation through several mechanisms mainly better osmotic adjustment, photoprotective mechanisms of PSII.

This study was conducted to assess the phytodiversity distribution in relation to altitudinal gradient in Salma Mountains, a naturally protected habitat in Ha’il region in the north of Saudi Arabia. Seventeen (17) sampling sites covering three altitudinal zones (i.e. valley, foot and top mountain) were randomly selected within the study area. Within each site and altitudinal zone, the floristic composition and the potential plant species of economic values were assessed and evaluated. A total number of 163 plant species belong to 101 genera and 41 families were identified in this study. Their economic values were also classified into forage (32%), edible (8.7%), medicinal (21.3%), ornamental (30.7%), weeds (18%) and rare species (14%). In addition, results obtained from different altitudinal zones of Salma Mountains, showed that 24 species were spread in the adjacent valley to the mountains, where 32 species spreading at the foot of the mountains and 40 found occupying the top of the mountains. The rest of species have been found to occupy larger geographical distribution in all altitudinal parts. Across the altitudinal gradients, species richness has been found to be consistent with a monotonically increasing pattern with a high richness at high altitudes. The current study suggests that such naturally protected ecosystem can provide a refuge for native plant species and serve as seed bank for a future restoration program in Ha’il region and other similar habitats in Saudi Arabia.

Assessing differences in plant functional traits (PFTs) along climatic gradients is potentially useful for understanding variation within and across populations, and for predicting their responses to climate change. This study investigates the intraspecific variability of several PFTs in Stipa tenacissima (Alpha grass) seedlings from different populations distributed across a climatic gradient. Seven populations from Tunisia to Spain within a 100–600 mm/year rainfall range were selected. Seedlings from each population were grown in a common garden. We expected the functional characteristics to differ among seedling populations according to their climatic gradient. The response patterns were helpful to predict acclimation and fitness under future climatic conditions in these populations. The seedling development analysis showed differences in PFTs among S. tenacissima populations. The biomass traits analysis revealed that higher above-ground biomass was related to higher below-ground development. The leaf traits proved that seedlings with longer leaf length would have less sclerophyllous leaves, a trade-off between productivity and drought resistance. The root traits analysis reflects seedling strategies to maximize resource uptake efficiency. PFTs showed several significant relationships with climatic conditions. The less rainfall, the higher plant allocation to root systems exploring soil. Higher mean temperatures were related to reduced root/plant development. The PFT analysis proves that species followed the ‘optimal partitioning theory’, in that plants preferentially allocate biomass to acquire the resource that most limits their development. However, both the environmental conditions and genetic diversity in S. tenacissima populations influenced seedling growth and behaviour to face ongoing climate change. AV’s work was partially funded by Projects CGL-2011-30531-CO2-02 and CGL2015-69773-C2-2-P MINECO/FEDER by the Spanish Government, and by the Prometeo Program (FEEDBACK project, 2009/006) by the Generalitat Valenciana. CEAM is supported by the Generalitat Valenciana.

A greenhouse pot experiment was conducted at the faculty of sciences of Gafsa to evaluate the effect of phosphorus treatment on two pistachio species. The seedlings of Pistacia vera and Pistacia atlantica were subjected to six levels of phosphoric acid (P2O5) (0, 5, 15, 30, 60 and 120 ppm). Stomatal conductance, net photosynthesis, chlorophyll fluorescence (OJIP) and total chlorophyll content were measured after 1, 2, 3, 6, 8, 9 and 12 weeks of treatment. During the experiment, phosphorus application at 5 ppm increased photosynthesis and stomatal conductance, relative to the treatment 0 ppm only in P. atlantica. However, phosphorus supply at 60 and 120 ppm induced toxicity leading to an inhibition of CO2 photo-assimilation rate, an alteration of photosystem II (PSII) structure and function and reduction in leaf chlorophyll content in both species. The (OJIP) transient showed complex changes in O-J, J-I and I–P phases of fluorescence. Due to phosphorus toxicity, both donor and acceptor sides of PSII were damaged, electron transport perturbed and chlorophyll pigment reduced which resulted in the fall of CO2 photo-assimilation rate, followed by mortality in both species.