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Olive mill wastewater (OMWW) was used in ferti-irrigation due to its high water content, as well as its organic and mineral richness. However, this by-product also contains elevated levels of polyphenols, which may pose phytotoxic risks to soil microbiota and plants over time. To address this concern, we conducted a thorough examination of the phenolic composition of OMWW and the phenolic content of amended soils using HPLC analysis. Additionally, we assessed the residual phytotoxicity of OMWW across various soil rhizospheric layers (0-30 cm, 30-60 cm, and 60-90 cm). Standard germination tests were performed using soil extracts with sorghum (Sorghum bicolor) and tomato (Solanum lycopersicum) seeds. We also measured α-amylase activities in the germinated seeds for both species, comparing them to raw OMWW and control soil extracts. HPLC analysis revealed that tyrosol, ferulic acid, and hydroxytyrosol were the predominant phenolic compounds in crude OMWW, while no detectable compounds were found in the soil extracts. Germination tests indicated minimal toxicity in the topsoil amended with OMWW, with a noticeable reduction in residual phytotoxicity at greater depths. These results aligned with the α-amylase activity assessments, which demonstrated significantly higher enzyme activity in the deeper soil layers (30-60 cm and 60-90 cm), with no substantial differences compared to control extracts., Competing Interests: Declarations Ethics approval All authors have read, understood, and have complied as applicable with the statement on “Ethical responsibilities of Authors” as found in the Instructions for Authors. Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The effect of water stress, salinity and temperature on the germination of Stipa capensis seeds were estimated herein. Seed germination was determined over different temperatures (10 °C, 15 °C, 20 °C, 25 °C and 30 °C), across a range of osmotic potentials of the polyethylene glycol solutions (0.0; −0.2; −0.5; −0.8; −1.6 MPa) and four salinity levels (0, 50; 100; 150 mmol/l−1) in four replicates of 50 caryopses for a period of 20 d. Results showed that temperature significantly affected the germinative percentage of Stipa capensis seeds (p <.001). The optimum temperature was 20 °C. The final germination percentage increased at the sub-optimal temperature range (10 °C–20 °C). However, from 20 to 30 °C, the final germination percentage decreased. The base temperature (Tb) was thus determined at 11.36 °C and the ceiling temperature (Tc) at 31.55 °C. Moreover, the highest germination percentage was found in osmotic potential 0 MPa (81 ± 2.4%). The increase in PEG6000 concentration resulted in an important decrease of germination percentage, with only 40% of seeds germinating at 0.8 MPa. Stipa capensis was also sensitive to high salinity (150 mmol/l−1) with a 29 ± 1.5 germination percentage. Overall, the study has shown the ability of Stipa capensis seed to germinate under low temperatures, water and salt stress that characterize most arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

Periploca angustifolia (Labill.) is a multipurpose xerophytic shrub in the Apocynaceae, which is widely disturbed in arid zones. This shrub is often used in programs for the rehabilitation of degraded areas, so it is essential to investigate the impact of environmental factors (drought, burial depth) on seed germination patterns. During 20 days, germination responses of seeds were determined over a wide range of constant temperatures (25 °C), polyethylene glycol PEG-6000 solutions of different osmotic potentials (0 to -1.6 MPa), and burial depths (1–8 cm). The highest germination percentages (99%) were obtained under control conditions without PEG, and increasing osmotic pressure progressively inhibited seed germination, which was about 2% at -1.6 MPa. When seeds were buried deep, there was a significant decrease in seedling emergence percentage and rate. Seedlings of P. angustifolia emerged well at depths of 1–2 cm with the highest emergence percentage of 74 and 69%, respectively. They could not emerge when the sand burial depth was higher than 4 cm. [ABSTRACT FROM AUTHOR]

The salinity of soils and irrigation water is among the main factors that limit plant productivity worldwide. Several alternatives have been proposed to get around this problem. However, these alternatives have faced difficulties in their implementation. As an alternative, the adverse effects of salinity on crop yield can be minimized by selecting species and varieties better adapted to salinity and/or by finding priming agents that give plants a certain tolerance during the vegetative and reproductive stages. The latter are strictly dependent on germination and seedling establishment. For this purpose, a laboratory experiment was conducted on three Tunisian wheat cultivars (Karim, Razeg, and Maali) subjected to moderate salinity stress (MSS, 5 g L−1 NaCl), severe salinity stress (SSS, 10 g L−1 NaCl), or control (0 NaCl) after soaking the seeds in a solution of KNO3 or ZnSO4 (0.5 g L−1). Salinity stress significantly decreased germination capacity (GC) and induced osmotic stress under MSS, which declined under SSS in favor of toxic stress. Pretreatment of seeds with KNO3 or ZnSO4 alleviated the toxic effect, and seedlings recovered initial vigor and GC even under SSS. The Karim cultivar showed better tolerance to salinity and a higher ability to react to priming agents. The calculated sensitivity tolerance index (STI) based on germination capacity, seedling growth, and initial vigor decreased in all cultivars under salt stress; however, this parameter clearly discriminated the studied cultivars. Karim was the most tolerant as compared to Razeg and Maali. We conclude that halopriming provides a benefit by alleviating the harmful effects of salt toxicity and that cultivars differ in their response to priming and extent of salt stress. KNO3 and ZnSO4 effectively alleviated the inhibitory effect of salt stress on seed germination and seedling establishment while significantly improving initial vigor. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This work stands for a modelling approach to identify the cardinal temperature of germination of Stipa tenacissima L., its capacity to recover and its adaptation potential considering dormancy and viability after exposure to salinity and drought. Seed traits characterised before germination were tested. The seeds were incubated at temperatures of 10 to 30 °C and low osmotic potentials were induced using sodium chloride (NaCl) or polyethylene glycol (PEG 6000) solutions of 0 to −1.6 MPa. The capacity of seeds to recover and remain viable under stress conditions was quantified. Our results proved that the seed yields and sizes were uniform. The analysis of cardinal temperature by thermal time model exhibited an optimal germination temperature (To) of about 19 °C, a base temperature (Tb) of 0.6 °C and a ceiling temperature (Tc) of 31 °C at 0 MPa. The base water potential Ψb (50) values ranged between −0.83 and −1.54 MPa and between −0.97 and −2.27 MPa for osmotic and salt stresses, at 30 °C and 20 °C, respectively. In conclusion, the species showed a lower seed recruitment related to a low drought tolerance (drought tolerance index = −0.5 MPa), To requirement and threshold sensitivity. Under salt stress, S. tenacissima used osmotic adjustment in order to germinate in a lower osmotic potential. [ABSTRACT FROM AUTHOR]

Reforestation projects are considered key climate change mitigation strategies, especially while considering native tree species as Ceratonia siliqua. The aims of this study were to evaluate the seed germination responses of three Tunisian accessions of Ceratonia siliqua, (Ichkeul (A1), Melloulech (A2), and Matmata (A3)), to temperature, water and salt stresses and their combination on germination aptitude. To overcome integumentary inhibition, we tested the different physical and chemical pre-treatments. Then, we subjected the seeds to different concentrations of NaCl and PEG (0 to −2 MPa), at different temperatures (from 10 to 35 °C). Results showed that the best pretreatment is soaking the seeds with 98% sulfuric acid for 20 minutes at 24 °C. The highest germination rate was observed at a temperature of 20 °C for A1 and 25 °C for A2 and A3. Using the hydrothermal time model, we found that the base water potential (Ψb), showed lower values in optimal range temperature (-2,19 MPa). All Ceratonia siliqua accessions showed a greater sensitivity to drought stress in germination and root growth in comparison with salt stress. The Ichkeul accession showed faster germination and better tolerance to stress. In conclusion, Ceratonia siliqua is thus recommended for restoration programs in arid and semi-arid ecosystems. [ABSTRACT FROM AUTHOR]

Restoration practices in arid ecosystems based on native species are urgently required to face desertification. In this context, knowledge about germination of species of arid ecosystems and seed enhancement technologies, such as seed priming to improve plant establishment, could be a basis to plan a restoration project. We assessed the effect of priming treatments to enhance germination in Stipa lagascae and Cenchrus ciliaris. Pretreated S. lagascae and C. ciliaris seeds (two levels of hydropriming, osmopriming and hardening) were subjected to diverse temperatures (20°C, 25°C and 30°C) and increasing drought stress levels (Ψw: −0.3 to −2 MPa). The priming tools, successfully implemented, enhanced seed and seedling performance. Hardened and osmoprimed C. ciliaris and S. lagascae seeds were found to germinate the most at 25°C and 20°C, up to about 96.7% and 90.84%, respectively. At Ψw = −1.6 MPa, no seed germination was observed in the two species in all priming pre-treatments. Pretreated grass seedlings exhibited sturdy strategies (seedling vigour up to 343), great plasticity (RDPI over 0.5) and a significant resource use efficiency. The hydrotime model analysis showed that priming slightly aids seeds of the two species in germination under lower water potential. In conclusion, priming could be a useful tool to improve germination rates, seedling establishment and plasticity under stressful drought conditions. Considering these results in the field of seed-based restoration and the identification of the most urgent research lines is paramount to guide the restoration practices. [ABSTRACT FROM AUTHOR]

In the saline depressions (Sebkhas) of Tunisia, Sulla carnosa expresses anarchic distribution, sometimes in association with halophytes sometimes individually. In order to explain this distribution, we investigated the effects of salinity on seed germination, the osmotic and toxic limiting factors, and the importance of some stimulating agents (priming agents) in the improvement of the tolerance to salinity at the germinating stage. A study was conducted on seeds harvested from the natural biotope Sebkha d'El Kelbia (35°50′34″N, 10°16′18″E), and an increasing concentration of NaCl (0, 5, 10, 15, and 20 g L−1) was applied. Some priming agents were used to propose efficient, rapid, and low‐cost tools to improve the seed germination and tolerance of Sulla carnosa (Desf.) in saline depression. Salinity stress significantly decreased germination capacity and rate and delayed its initiation and maximum. Until 15‐g L−1 NaCl, the most limiting factor of seed germination is the osmotic effect. At 20‐g L−1 NaCl, the toxic effect dominates, and germination is irreversibly inhibited. Some priming agents have shown their efficiency in improving the germination capacity at 10‐g L−1 NaCl and conferring a salt tolerance of up to 15‐g L−1 NaCl. [ABSTRACT FROM AUTHOR]

Abstract: The interest of the scientific community in biological soil crusts has grown exponentially over the last decades. One of the scientific research interests is the study of the effect of these crusts on plant establishment. Findings in this topic have been controversial, and some differences were attributed to crust types. Biological soil crusts dominated by lichens are common components of Stipa tenacissima steppes in arid and semi‐arid environments of the southern Mediterranean. In the current study, we conducted growth chamber experiments to investigate the differential effects of two lichen species with continuous crustose thalli (Diploschistes diacapsis) and with squamulose semicontinuous thalli (Fulgensia bracteata) on seed germination, root penetration, shoot emergence and seed viability of the tussock grass species S. tenacissima. Our results showed that under laboratory conditions, two distinct lichen species had significantly different effects on the establishment of S. tenacissima. Our findings clearly demonstrated that D. diacapsis significantly decreased germination, root penetration and shoot emergence of S. tenacissima compared to F. bracteata. This can be related to differences in morphological and physiological characteristics between crustose and squamulose lichens. Overall, we suggest that D. diacapsis and crustose lichens generally can act as natural barrier to the establishment of S. tenacissima. [ABSTRACT FROM AUTHOR]

Highlights • Olive oil industry is the most important sector in the Mediterranean countries. • Olive oil industry generates massive amounts of olive mill wastewater (OMW). • OMW constitutes a serious environmental and economic problem. • OMW can be used as soil organic fertilizer. Abstract Produced in huge quantities, olive mill wastewater (OMW) causes serious environmental problems in the Mediterranean basin, where olive growing is concentrated. The purpose of this study has been to evaluate the short term effects of various OMW quantities application on several Sorghum bicolor agro-physiological and biochemical parameters as well as the effects on the main properties of the amended soils. Four doses of OMW (25, 50, 75 and 100 m³ haˉ¹) have been applied in comparison to control soil not treated with OMW. Results have showed an improvement of the organic matter, total nitrogen and minerals contents in soils treated with OMW proportionally to the increase of the doses applied. Moreover, soils microbiological activities have been strongly enhanced in comparison with control soil. Furthermore, the study of the effects of OMW on the Sorghum bicolor seeds germination has showed that raw OMW has blocked germination seeds. However, various effects on Sorghum bicolor seeds germination have been observed for the OMW amended soils extracts related to quantities applied. An improvement of the main agro-physiological and biochemical parameters as stems height, stems thickness, leaves number, leaves circumferences', roots lengths, plant productivity, proteins content and essential minerals elements rates for the plants growing in soil treated with 25 m3 ha−1 OMW dose has been reported. Nevertheless, clear inhibitions have been observed for the highest OMW doses applied as 75 and 100 m3 ha−1. [ABSTRACT FROM AUTHOR]

Abstract: Given its importance in the functioning of arid ecosystems, Ephedra alata ssp. alenda has drawn some attention and appeared to be suitable for desert re-vegetation. An experimental study has been carried out on the germination properties of seeds of this strictly Saharan species. Analyses of temperature effects, and fungicide seed treatments in the laboratory and the field enabled to determine the optimum germination conditions. The predominant microorganisms isolated from the E. alata ssp. alenda seeds before treatment were Alternaria alternata and Rhizopus spp. The germination capacity was significantly greater between 20 and 25°C. Captab (61.1 %) and propiconazole (53.2%) fungicides significantly increased the germination of E. alata seeds. These results are confirmed by experiments in the field where all treatments (except treatments with NaOCl and benomyl) significantly increased the emergence percentage. None of the treatments (except benomyl) affected the shoot and root length of the plants. Benomyl treatment resulted in a significant decrease in the shoot and root length. [Copyright &y& Elsevier]