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Cadmium (Cd) is a highly toxic heavy metal. Its emission is suspected to be further increased due to the dramatic application of ash to agricultural soils and newly reclaimed ones. Thereby, Cd stress encountered by plants will exacerbate. Acute and chronic exposure to Cd can upset plant growth and development and ultimately causes plant death. Microorganisms as agriculturally important biofertilizers have constantly been arising as eco-friendly practices owing to their ability to built-in durability and adaptability mechanisms of plants. However, applying microbes as a biofertilizer agent necessitates the elucidation of the different mechanisms of microbe protection and stabilization of plants against toxic elements in the soil. A greenhouse experiment was performed using Trichoderma harzianum and plant growth-promoting (PGP) bacteria (Azotobacter chroococcum and Bacillus subtilis) individually and integrally to differentiate their potentiality in underpinning various resilience mechanisms versus various Cd levels (0, 50, 100, and 150 mg/kg of soil). Microorganisms were analyzed for Cd tolerance and biosorption capacity, indoleacetic acid production, and phosphate and potassium solubilization in vitro. Plant growth parameters, water relations, physiological and biochemical analysis, stress markers and membrane damage traits, and nutritional composition were estimated.
Results: Unequivocal inversion from a state of downregulation to upregulation was distinct under microbial inoculations. Inoculating soil with T. harzianum and PGPB markedly enhanced the plant parameters under Cd stress (150 mg/kg) compared with control plants by 4.9% and 13.9%, 5.6% and 11.1%, 55.6% and 5.7%, and 9.1% and 4.6% for plant fresh weight, dry weight, net assimilation rate, and transpiration rate, respectively; by 2.3% and 34.9%, 26.3% and 69.0%, 26.3% and 232.4%, 135.3% and 446.2%, 500% and 95.6%, and 60% and 300% for some metabolites such as starch, amino acids, phenolics, flavonoids, anthocyanin, and proline, respectively; by 134.0% and 604.6% for antioxidants including reduced glutathione; and by 64.8% and 91.2%, 21.9% and 72.7%, and 76.7% and 166.7% for enzymes activity including ascorbate peroxidase, glutathione peroxidase, and phenylalanine ammonia-lyase, respectively. Whereas a hampering effect mediated by PGP bacterial inoculation was registered on levels of superoxide anion, hydroxyl radical, electrolyte leakage, and polyphenol oxidase activity, with a decrease of 0.53%, 14.12%, 2.70%, and 5.70%, respectively, under a highest Cd level (150 mg/kg) compared with control plants. The available soil and plant Cd concentrations were decreased by 11.5% and 47.5%, and 3.8% and 45.0% with T. harzianum and PGP bacterial inoculation, respectively, compared with non-inoculated Cd-stressed plants. Whereas, non-significant alternation in antioxidant capacity of sunflower mediated by T. harzianum action even with elevated soil Cd concentrations indicates stable oxidative status. The uptake of nutrients, viz., K, Ca, Mg, Fe, nitrate, and phosphorus, was interestingly increased (34.0, 4.4, 3.3, 9.2, 30.0, and 1.0 mg/g dry weight, respectively) owing to the synergic inoculation in the presence of 150 mg of Cd/kg.
Conclusions: However, strategies of microbe-induced resilience are largely exclusive and divergent. Biofertilizing potential of T. harzianum showed that, owing to its Cd biosorption capability, a resilience strategy was induced via reducing Cd bioavailability to be in the range that turned its effect from toxicity to essentiality posing well-known low-dose stimulation phenomena (hormetic effect), whereas using Azotobacter chroococcum and Bacillus subtilis, owing to their PGP traits, manifested a resilience strategy by neutralizing the potential side effects of Cd toxicity. The synergistic use of fungi and bacteria proved the highest efficiency in imparting sunflower adaptability under Cd stress.
In this study, we utilized pomegranate peel and marine algae Ulva lactuca (U. lactuca) as rich and sustained sources of bioactive compounds to combat tomato-black spot disease. n-Hexane extracts from the peel of pomegranate (Punica granatum) (PPE) and the marine algal biomass U. lactuca (ULE) were used alone and in combinations to verify their impact against Alternaria alternata (A. alternata). The applied extracts exhibited severe destructive effects on both fungal growth and structure such as mycelia malformation, underdeveloped conidia, cell wall deformation, and shrinkage. Moreover, increased deformations and protrusions, and notch-like structures, were noticed in A. alternata mycelia treated with mixed extracts (PPE and ULE) compared to all other treatments. The protein and reduced sugar contents in tomato fruits were significantly increased in the infected fruits with A. alternata. The highest enzyme activities of pectinase, cellulase, catalase (CAT), and ascorbate peroxidase (APX) were recorded in infected tomatoes in comparison with the healthy ones. Molecular docking studies showed that each extract is rich with bioactive compounds that have a promising inhibition effect on A. alternata cellulases. Pomegranate and Ulva extract showed promising antifungal activity against A. alternata which revealed their feasibility and applicability as biocontrol agents in postharvest disease management and food preservation against fungal pathogens.
Global agriculture is a pivotal activity performed by various communities worldwide to produce essential
human food needs. Plant productivity is limited by several factors, such as salinity, water scarcity, and heat stress.
Salinity significantly causes short or long-term impacts on the plant photosynthesis mechanisms by reducing the
photosynthetic rate of CO 2 assimilation and limiting the stomatal conductance. Moreover, disturbing the plant water
status imbalance causes plant growth inhibition. Up-regulation of several plant phytohormones occurs in response to
increasing soil salt concentration. In addition, there are different physiological and biochemical mechanisms of salt
tolerance, including ion transport, uptake, homeostasis, synthesis of antioxidant enzymes, and osmoprotectants.
Besides that, microorganisms proved their ability to increase plant tolerance, Bacillus spp. represents the dominant
bacteria of the rhizosphere zone, characterised as harmless microbes with extraordinary abilities to synthesise many
chemical compounds to support plants in confronting salinity stress. In addition, applying arbuscular mycorrhizal
fungi (AMF) is a promising method to decrease salinity-induced plant damage as it could enhance the growth rate
relative to water content. In addition, there is a demand to search for new salt-tolerant crops with more yield and
adaptation to unfavourable environmental conditions. The negative impact of salinity on plant growth and
productivity, photosynthesis, stomatal conductance, and changes in plant phytohormones biosynthesis, including
abscisic acid and salicylic acid, jasmonic acid, ethylene, cytokinins, gibberellins, and brassinosteroids was discussed in
this review. The mechanisms evolved to adapt and/or survive the plants, including ion homeostasis, antioxidants, and
osmoprotectants biosynthesis, and the microbial mitigate salt stress. In addition, there are modern approaches to apply
innovative methods to modify plants to tolerate salinity, especially in the essential crops producing probable yield with
a notable result for further optimisation and investigations
Heterostructure Cu2O@CuO nanosheets are spontaneously formed during the kinetic-spraying of nanostructured CuO thin film on the fluorine-doped tin oxide (FTO) substrate at room temperature under low vacuum conditions by the NPDS technique. The Cu2O@CuO nanosheets fabricated as a heterogeneous electrocatalyst are utilized for free enzyme detection of glucose and H2O2 in 0.1 M NaOH, whereby the synergy between the multivalent copper species (I and II) results in an overall improvement of electrocatalytic performance. The in-situ formation of interfacial Cu2O@CuO heterostructure is verified using a high-resolution transmission microscope and x-ray photon electron spectroscopy. The fabricated electrocatalysts exhibit high sensitivity toward glucose oxidation of 818.5 μA·mM-1·cm-2 with a wide linear detection range extending from 0.02 to 5 mM and a limit of detection (LOD) of 5.8 μM. Also, the heterostructure Cu2O@CuO nanosheets show a very wide linear detection range of H2O2 oxidation from 0.02 to 11 mM with a good detection sensitivity of 168 μA·mM-1·cm-2 and a LOD of 8.75 μM. The long-term stability for around 30 min and high oxidation selectivity with other interfering species are verified. Furthermore, Cu2O@CuO nanosheets exhibit higher catalytic rate constant and diffusion coefficient toward glucose species compared with H2O2.
Abstract: Cadmium (Cd) deposition and salinity are combined environmental stresses in coastal or 16 dry areas irrigated with non-treated wastewater. In those areas, halophytes have been found to be 17 more effective in the phytoextraction of metals rather than Cd-hyperaccumulating glycophytes that 18 are unqualified for growing in saline soil. Nevertheless, the impact of salt on the accumulation pro-19 prieties of Cd in a variety of halophytic species remains undetermined. The hydroponic culture was 20 used to investigate the impact of salinity on Cd tolerance as well as accumulation in distinct halo-21 phyte Salicornia fruticosa. The plant was subjected to 0, 25, and 50 μg l−1 Cd (0-Cd, L-Cd, and H-Cd, 22 respectively) in combination with or without 50, 100, and 200 mM NaCl in the nutrient solution. 23 Data demonstrated that Cd individually induced depletion in biomass accumulation. The NaCl-24 amplified Cd tolerance induced by enhanced biomass gaining and root length was associated with 25 adequate transpiration, leaf succulence, elevated levels of ascorbic acid (ASA), reduced glutathi-26 one, and phytochelatins (PCs) and proline as well as antioxidant enzymatic capacity via upregula-27 tion of peroxidases (PO), glutathione peroxidase, ascorbate peroxidase, and superoxide dismutase. 28 All Cd treatments decreased the uptake of calcium (Ca) as well as potassium (K) and transit to the 29 shoots; however, sodium (Na) accumulation in the shoots was not influenced by Cd. Consequently, 30 S. fruticosa retained its halophytic properties. Based on the low transfer efficiency and high enrich-31 ment coefficient at 0-50 mM, an examination of Cd accumulation characteristics revealed that phy-32 tostabilization was the selected phytoremediation strategy. At 100-200 mM, the high ground parts 33 Cd-translocation and high absorption efficiency encourage phytoremediation via phytoextraction. 34 The results revealed that S. fruticosa could be potentially utilized to renovate saline soils tainted with 35 heavy metals (HMs) because of its maximized capacity for Cd tolerance as well as enrichment mag-36 nified by NaCl. Cd accumulation in S. fruticosa is affected differently depending on the NaCl con-37 centration. Future studies may be conducted to detect other heavy metal pollutants screening that 38 could be extracted and stabilized by the S. fruticosa plant. Furthermore, other substrates presenting 39 a high electrical conductivity should be identified for reclamation.
The subsurface and surface structural geometries of the United Arab Emirates (UAE) fold-andthrust
belt (FTB) and foreland basins are interpreted from seismic, well data, and surface geology. Twelve
horizons ranging in age from Miocene to Lower Jurassic were interpreted and mapped. Additionally,
we outlined subsurface extent of Sumeini and Hawasina allochthonous nappes. The tectonic subsidence
curves suggest that the final major passive margin rifting event occurred in the early Aalenian and lasted
till Oxfordian. Loading of the Semail ophiolite thrust sheet and accompanying allochthonous thrust sheets
resulted in uplift at ca. 95 Ma and rapid subsidence at ca. 83 Ma, indicating the transition of the Arabian
margin from a rifted passive margin to a foreland basin. The region witnessed an accelerated subsidence
during the late Oligocene-Miocene, attributed to the initial collision of the Central Iran and Arabian plates.
The Permian-Jurassic NW-SE oriented rift faults were reactivated as thrust faults during the Late Cretaceous
ophiolite obduction and late Oligocene-Miocene continental collision. Two different tectonic regimes are
identified in the FTB. The northern regime is characterized by major inversion of the rift faults with up to
3,700 m throw, whereas the southern regime has a major pop-up structure with possible basement origin.
Four major west-verging and east-dipping thrusts, which cross the northern area, form fault-propagation folds
and dissect the entire stratigraphy. Moreover, the Hawasina décollement, together with the inverted basement
structures formed the Jabal Hafit anticline as a backthrust structure.