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BACKGROUND: Selenium (Se) fertilizer and arbuscular mycorrhizal fungi (AMF) are known to modulate cadmium (Cd) toxicity in plants. However, the effects of their co-application on wheat growth and soil microbial communities in Cd-contaminated soil are unclear. RESULTS: A pot experiment inoculation with two types of AMF and the application of Se fertilizer under Cd stress in wheat showed that inoculation AMF alone or combined with Se fertilizer significantly increased wheat biomass. Se and AMF alone or in combination significantly reduced available Cd concentration in wheat and soil, especially in the Se combined with Ri treatment. High throughput sequencing of soil samples indicated that Se and AMF application had stronger influence on bacterial community compared to fungal community and the bacterial network seemed to have more complex interconnections than the fungal network, and finally shaped the formation of specific microflora to affect Cd availability. CONCLUSION: These results indicate that the application of Se and AMF, particularly in combination, could successfully decrease soil Cd availability and relieve the harm of Cd in wheat by modifying rhizosphere soil microbial communities.
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Biomassa , Cádmio , Fertilizantes , Micorrizas , Rizosfera , Selênio , Microbiologia do Solo , Triticum , Triticum/crescimento & desenvolvimento , Triticum/microbiologia , Triticum/efeitos dos fármacos , Micorrizas/fisiologia , Cádmio/análise , Cádmio/toxicidade , Fertilizantes/análise , Selênio/metabolismo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Microbiota/efeitos dos fármacosRESUMO
INTRODUCTION: In glioma patients that have undergone surgical tumor resection, the ability to reliably distinguish between pseudoprogression (PsP) and a recurrent tumor (RT) is of key clinical importance. Accordingly, this meta-analysis evaluated the utility of dynamic susceptibility contrast-enhanced perfusion-weighted imaging as a means of distinguishing between PsP and RT when analyzing patients with high-grade glioma. MATERIALS AND METHODS: The PubMed, Web of Science, and Wanfang databases were searched for relevant studies. Pooled analyses of sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) values were conducted, after which the area under the curve (AUC) for summary receiver operating characteristic curves was computed. RESULTS: This meta-analysis ultimately included 21 studies enrolling 879 patients with 888 lesions. Cerebral blood volume-associated diagnostic results were reported in 20 of the analyzed studies, and the respective pooled sensitivity, specificity, PLR, and NLR values were 86% (95% confidence interval [CI], 0.81-0.89), 83% (95% CI, 0.77-0.87), 4.94 (95% CI, 3.61-6.75), and 0.18 (95% CI, 0.13-0.23) for these 20 studies. The corresponding AUC value was 0.91 (95% CI, 0.88-0.93), and the publication bias risk was low ( P = 0.976). Cerebral blood flow-related diagnostic results were additionally reported in 6 of the analyzed studies, with respective pooled sensitivity, specificity, PLR, and NLR values of 85% (95% CI, 0.78-0.90), 85% (95% CI, 0.76-0.91), 5.54 (95% CI, 3.40-9.01), and 0.18 (95% CI, 0.12-0.26). The corresponding AUC value was 0.92 (95% CI, 0.89-0.94), and the publication bias risk was low ( P = 0.373). CONCLUSIONS: The present meta-analysis results suggest that dynamic susceptibility contrast-enhanced perfusion-weighted imaging represents an effective diagnostic approach to distinguishing between PsP and RT in high-grade glioma patients.
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Neoplasias Encefálicas , Glioma , Humanos , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Sensibilidade e Especificidade , Glioma/diagnóstico por imagem , Glioma/patologia , Angiografia por Ressonância Magnética , PerfusãoRESUMO
The application of nitrification inhibitors (nitrapyrin) and urease inhibitors (N-(N-butyl) thiophosphoric triamide) under conventional water resources has been considered as an effective means to improve nitrogen utilization efficiency and mitigate soil greenhouse gas emissions. However, it is not known whether the inhibitors still have an inhibitory effect under unconventional water resources (reclaimed water and livestock wastewater) irrigation and whether their use in combination with biochar improves the mitigation effect. Therefore, unconventional water resources were used for irrigation, with groundwater (GW) control. Nitrapyrin and N-(N-butyl) thiophosphoric triamide were used alone or in combination with biochar in a pot experiment, and CO2, N2O, and CH4 emissions were measured. The results showed that irrigation of unconventional water resources exacerbated global warming potential (GWP). All exogenous substance treatments increased CO2 and CH4 emissions and suppressed N2O emissions, independent of the type of water, compared to no substances (NS). The inhibitors were ineffective in reducing the GWP whether or not in combination with biochar, and the combined application of inhibitors with biochar further increased the GWP. This study suggests that using inhibitors and biochar in combination to regulate the greenhouse effect under unconventional water resources irrigation should be done with caution.
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Agricultura , Carvão Vegetal , Gado , Compostos Organofosforados , Animais , Agricultura/métodos , Águas Residuárias , Aquecimento Global , Dióxido de Carbono/análise , Óxido Nitroso/análise , Solo , Fertilizantes , MetanoRESUMO
BACKGROUND: Selenium (Se) deficiency causes a series of health disorders in humans, and Se concentrations in the edible parts of crops can be improved by altering exogenous Se species. However, the uptake, transport, subcellular distribution and metabolism of selenite, selenate and SeMet (selenomethionine) under the influence of phosphorus (P) has not been well characterized. RESULTS: The results showed that increasing the P application rate enhanced photosynthesis and then increased the dry matter weight of shoots with selenite and SeMet treatment, and an appropriate amount of P combined with selenite treatment increased the dry matter weight of roots by enhancing root growth. With selenite treatment, increasing the P application rate significantly decreased the concentration and accumulation of Se in roots and shoots. P1 decreased the Se migration coefficient, which could be attributed to the inhibited distribution of Se in the root cell wall, but increased distribution of Se in the root soluble fraction, as well as the promoted proportion of SeMet and MeSeCys (Se-methyl-selenocysteine) in roots. With selenate treatment, P0.1 and P1 significantly increased the Se concentration and distribution in shoots and the Se migration coefficient, which could be attributed to the enhanced proportion of Se (IV) in roots but decreased proportion of SeMet in roots. With SeMet treatment, increasing the P application rate significantly decreased the Se concentration in shoots and roots but increased the proportion of SeCys2 (selenocystine) in roots. CONCLUSION: Compared with selenate or SeMet treatment, treatment with an appropriate amount of P combined with selenite could promote plant growth, reduce Se uptake, alter Se subcellular distribution and speciation, and affect Se bioavailability in wheat.
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Selênio , Humanos , Selênio/metabolismo , Ácido Selênico , Triticum/metabolismo , Fertilizantes , Fósforo/metabolismo , Ácido Selenioso/metabolismoRESUMO
Boron (B) is an essential microelement for plant growth and has been shown to reduce cadmium (Cd) toxicity in wheat through modulating gene expression. However, there is not enough information about the effects of different applications of B fertilizer on the accumulation of Cd, particularly throughout the wheat growth period. This experiment employed two different B fertilization methods. The soil application method utilized 1.5 mg B kg-1 soil (Cd+B) and foliar application utilized 0.1% (F0.1%), 0.3% (F0.3%), and 0.6% (F0.6%) B concentrations along with 4 mg kg-1 Cd. The results showed that B application in the soil reduced Cd concentrations per plant by 43.9% at the seedling stage, 74.59% in the roots, and 52.11% in the shoots at the elongation stage. At the same time, Cd concentrations in the roots were higher by B application at the anthesis and maturity stages, suggesting that B retains more Cd in the roots. The gray correlation analysis showed that the gray relational coefficients followed the following order: F0.3% > F0.1% > Cd+B > F0.6%. According to quantitative real-time PCR analysis, the six Cd transporters were mostly expressed in the roots at the seedling stage and anthesis stage. In addition, the expression of TCONS1113, TRIAE1060, and TRIAE5370 showed a negative correlation relationship with Cd concentration at the seedling stage, both in roots and shoots. At the anthesis stage, the expression of TCONS1113 and TRIAE5370 in roots was higher in Cd-treated plants compared to B-treated plants, and a similar tendency was noted for the expression of TRIAE5770 and TRIAE1060 in shoots as well. These results suggest that B application could significantly inhibit Cd uptake and translocation by regulating the expression of Cd transporter genes, especially at the seedling stage and the elongation phase in wheat.
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Cádmio , Poluentes do Solo , Boro/análise , Boro/toxicidade , Cádmio/metabolismo , Raízes de Plantas/metabolismo , Plântula/metabolismo , Solo , Poluentes do Solo/análise , TriticumRESUMO
BACKGROUND: Cadmium (Cd) accumulation in crops affects the yield and quality of crops and harms human health. The application of selenium (Se) can reduce the absorption and transport of Cd in winter wheat. RESULTS: The results showed that increasing Se supply significantly decreased Cd concentration and accumulation in the shoot and root of winter wheat and the root-to-shoot translocation of Cd. Se application increased the root length, surface area and root volume but decreased the average root diameter. Increasing Se supply significantly decreased Cd concentration in the cell wall, soluble fraction and cell organelles in root and shoot. An increase in Se supply inhibited Cd distribution in the organelles of shoot and root but enhanced Cd distribution in the soluble fraction of shoot and the cell wall of root. The Se supply also decreased the proportion of active Cd (ethanol-extractable (FE) Cd and deionized water-extractable (FW) Cd) in root. In addition, the expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 significantly increased with increasing Cd concentration in root, and the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root was downregulated by increasing Se supply, regardless of Se supply or Cd stress. The expression of TaHMA3-b in root was significantly downregulated by 10 µM Se at both the 5 µM and 25 µM Cd level but upregulated by 5 µM Se at the 25 µM Cd level. The expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 in shoot was downregulated by increasing Se supply at 5 µM Cd level, and 5 µM Se upregulated the expression of those genes in shoot at 25 µM Cd level. CONCLUSIONS: The results confirm that Se application limits Cd accumulation in wheat by regulating the subcellular distribution and chemical forms of Cd in winter wheat tissues, as well as the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root.
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Cádmio/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Plantas/metabolismo , Selênio/metabolismo , Triticum/metabolismo , Transporte Biológico , Cádmio/química , Regulação da Expressão Gênica de Plantas , Proteínas de Membrana Transportadoras/genética , Proteínas de Plantas/genética , Raízes de Plantas/química , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Brotos de Planta/química , Brotos de Planta/genética , Brotos de Planta/metabolismo , Plântula/química , Plântula/genética , Plântula/metabolismo , Frações Subcelulares/química , Triticum/química , Triticum/genéticaRESUMO
The different wheat varieties have different tolerance to cadmium stress, while the mechanisms underlying the Cd tolerance are still poorly understood. A pot experiment was conducted to study the changes of antioxidant enzyme activities and endogenous hormones in wheat (Triticum aestivum) genotypes differing in cadmium (Cd) accumulation (low = Pingan 8 and high = Bainong 160) in different growth stages under Cd stress. The Cd treatment (3â¯mg/kg) increased the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and concentrations of malondialdehyde (MDA) and abscisic acid (ABA); in contrast, it reduced the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), intercellular carbon dioxide concentration (Ci) and the concentrations of gibberellin (GA3), auxin (IAA) and zeatin nucleoside (ZR) in wheat leaves compared to the CK (without Cd). The antioxidant enzyme activities were higher in Bainong 160 than Pingan 8 under Cd stress. In addition, the changes in endogenous hormone concentration were smaller in Bainong 160 than Pingan 8 leaves. The correlation coefficients of Bainong 160 and Pingan 8 were 0.87 and 0.66, respectively. Our results suggest that high Cd accumulation (greater Cd tolerance) in Bainong 160 is associated with higher photosynthetic parameters, higher activities of antioxidant enzyme and higher concentration of hormones than Pingan 8.
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Cádmio/toxicidade , Estresse Fisiológico , Triticum/efeitos dos fármacos , Ácido Abscísico/análise , Catalase/metabolismo , Giberelinas/análise , Ácidos Indolacéticos/análise , Malondialdeído/metabolismo , Peroxidases/metabolismo , Fotossíntese/efeitos dos fármacos , Reguladores de Crescimento de Plantas/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Superóxido Dismutase/metabolismo , Triticum/enzimologia , Zeatina/análiseRESUMO
Wheat (Triticum aestivum L.) has relatively high tolerance to cadmium (Cd), but the underlying mechanisms are poorly understood. Growth and physiological parameters of wheat exposed to different Cd concentrations (0, 0.5, 5 and 50 µM) were characterized. The fresh weight, leaf chlorophyll and carotenoid concentrations and photosynthesis parameters did not differ among Cd treatments, suggesting relatively high Cd tolerance in wheat. However, the soluble sugar concentrations increased with the increasing Cd concentration and the soluble protein concentrations decreased in both shoots and roots, suggesting that the Cd application promoted nitrogen metabolism over carbon metabolism. In addition, the higher concentrations of MDA, GSH and AsA and activities of antioxidant enzymes (SOD, POD, and CAT) were observed in leaves and roots in the Cd50 treatment. Our results reveal that wheat can tolerate Cd by enhancing the antioxidant enzymes activities and increasing the concentration of ascorbate and glutathione.
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Antioxidantes/metabolismo , Cádmio/metabolismo , Glutationa/metabolismo , Triticum/metabolismo , Ácido Ascórbico/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Fotossíntese , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Superóxido Dismutase/metabolismoRESUMO
PURPOSE OF REVIEW: Intraoperative changes in somatosensory (SEP) and motor evoked potentials (MEPs) may indicate potential injury to the spinal cord and will require timely intervention to prevent permanent damage. This review focuses on the validity of currently recommended warning criteria for intraoperative evoked potential monitoring. RECENT FINDINGS: Current guideline recommends a decrease in SEP amplitude by 50% and MEP amplitude by 50-100% as warning signals for injury to the ascending sensory and descending motor pathway, respectively. On the basis of cohort studies, the diagnostic accuracy of SEP and MEP to predict postoperative neurologic deficits was variable. Importantly, 0.1-4.1% of monitored patients suffered postoperative neurologic deficit despite apparently normal SEP and MEP recordings (i.e. false negative events). These data suggested that the true warning criteria may be lower than previously acknowledged. A systematic review of studies that reported changes in SEP or MEP monitoring and postoperative neurological outcome showed an association between changes in monitoring signals and postoperative neurological deficits. However, the confidence intervals were wide and it is not possible to determine a threshold value in SEP or MEP amplitude beyond which may indicate neurologic deficit. SUMMARY: Current recommendations for warning criteria during intraoperative evoked potential monitoring are empirically derived. Until a threshold that predicts spinal cord injury can be accurately determined, it remains difficult to define the clinical utility of intraoperative neurophysiologic monitoring.
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Potencial Evocado Motor , Potenciais Somatossensoriais Evocados , Monitorização Neurofisiológica Intraoperatória , Humanos , Traumatismos da Medula Espinal/prevenção & controleRESUMO
[This corrects the article DOI: 10.3389/fpsyg.2024.1363562.].
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Numerous studies have explored the effects of background music on reading comprehension, however, little is known about how native language (L1) lyrics and second language (L2) lyrics in background music influence reading comprehension performance for college students. The present study used a mixed experimental design to examine the effects of listening habits (between-participants variable: non-listeners or listeners), music type (between-participants variable: L1 (Mandarin) pop music, L2 (English) pop music or no music) and text language (within-participants variable: L1 or L2) on reading comprehension of college students in East China. A total of 90 participants (50 females) were screened into non- listeners (n = 45) and listeners (n = 45), and then were randomly assigned to one of three groups: Mandarin pop music group (n = 30), English pop music group (n = 30) and no music group (n = 30). The results showed that reading comprehension performance was negatively affected by music with lyrics compared to the no music condition. Furthermore, Chinese/English reading comprehension was reduced more by pop music in the same language as the written texts. As expected, non-listeners were more negatively affected by music with lyrics than listeners. For both listeners and non-listeners, average reading comprehension accuracy rates were the lowest in the condition of music with native language lyrics. Overall, our research findings indicate that listening to pop music with lyrics reduces reading comprehension performance. However, listening to background music cause much less distraction if the students commonly listen to music while reading. The current study supports the duplex-mechanism account of auditory distraction.
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Cadmium (Cd) contamination in agricultural soils has emerged as a significant concern, particularly due to its potential impact on plant-based food. Soil pH reductions can exacerbate Cd mobility, leading to excessive accumulation in crops. While liming has been demonstrated as an effective method to mitigate Cd accumulation in rice grains in acid soils of southern China, its efficacy in remediating acid soils in northern China remains unclear. In this study, a multi-year field experiment was conducted on farmland impacted by zinc ore smelting at coordinates of 33.92° N 112.46° E to investigate the use of limestone for controlling Cd accumulation in wheat and maize grains. The results indicated that applying 7.5 t ha-1 of limestone significantly raised the soil pH from 4.5 to 6.8 as anticipated. Different rates of limestone application (2.25, 4.45, and 7.50 t ha-1) reduced Cd bioavailability in the soil by 20-54%, and Cd accumulation in wheat grains by 5-38% and maize grains by 21-63%, without yield penalty. The remediation effects were sustained for at least 27 months, highlighting limestone as a promising ameliorant for smelting-affected farmland in northern China.
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There are many heavy metal stresses in agricultural biological systems, especially cadmium (Cd) stress, which prevent the full growth of plants, lead to a serious decline in crop yield, and endanger human health. Molybdenum (Mo), an essential nutrient element for plants, regulates plant growth mainly by reducing the absorption of heavy metals and protecting plants from oxidative damage. The aim of this study was to determine the protective effect of Mo (1 µM) application on wheat plants under conditions of Cd (10 µM) toxicity. The biomass, Cd and Mo contents, photosynthesis, leaf and root ultrastructure, antioxidant system, and active oxygen content of the wheat plants were determined. Mo increased the total chlorophyll content of wheat leaves by 43.02% and the net photosynthetic rate by 38.67%, and ameliorated the inhibitory effect of cadmium on photosynthesis by up-regulating photosynthesis-related genes and light-trapping genes. In addition, Mo reduced the content of superoxide anion (O2â¢-) by 16.55% and 31.12%, malondialdehyde (MDA) by 20.75% and 7.17%, hydrogen peroxide (H2O2) by 24.69% and 8.17%, and electrolyte leakage (EL) by 27.59% and 16.82% in wheat leaves and roots, respectively, and enhanced the antioxidant system to reduce the burst of reactive oxygen species and alleviate the damage of Cd stress on wheat. According to the above results, Mo is considered a plant essential nutrient that enhances Cd tolerance in wheat by limiting the absorption, accumulation and transport of Cd and by regulating antioxidant defence mechanisms. ENVIRONMENTAL IMPLICATION: Cadmium (Cd)ï¼is one of the most toxic heavy metals in the environment, and Cd pollution is a global environmental problem that threatens food security and human health. Molybdenum (Mo), as an essential plant nutrient, is often used to resist environmental stress. However, the mechanism of Mo treatment on wheat subjected to Cd stress has not been reported. In this study, we systematically analysed the effects of Mo on the phenotype, physiology, biochemistry, ultrastructure and Cd content of wheat subjected to Cd stress, and comprehensively analysed the transcriptomics. It not only reveals the mechanism of Mo tolerance to Cd stress in wheat, but also provides new insights into phytoremediation and plant growth in Cd-contaminated soil.
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Cádmio , Molibdênio , Fotossíntese , Folhas de Planta , Triticum , Triticum/efeitos dos fármacos , Triticum/metabolismo , Triticum/genética , Cádmio/toxicidade , Molibdênio/toxicidade , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Transcriptoma/efeitos dos fármacos , Clorofila/metabolismo , Peróxido de Hidrogênio , Estresse Oxidativo/efeitos dos fármacos , Malondialdeído/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacosRESUMO
Cadmium (Cd) contamination is a serious challenge in agricultural soils worldwide, resulting in Cd entering the food chain mainly through plant-based food and threatening human health. Minimizing Cd bioaccumulation in wheat is an important way to prevent Cd hazards to humans. Hydroponic and pot experiments were conducted to comprehensively evaluate the effects of zinc sulfate (ZnSO4) and zinc oxide nanoparticles (nZnO) on Cd uptake, translocation, subcellular distribution, cellular ultrastructure, and gene expression in two wheat genotypes that differ in grain Zn accumulation. Results showed that high-dose nZnO significantly reduced root Cd concentration (52.44%â¼56.85%) in two wheats, in contrast to ZnSO4. The S216 exhibited higher tolerance to Cd compared to Z797. Importantly, Zn supplementation enhanced Cd sequestration into vacuoles and binding to cell walls, which conferred stability to ultracellular structures and photosynthetic apparatus. Down-regulation of influx transporter (TaHMA2 and TaLCT1) and up-regulation of efflux transporters (TaTM20 and TaHMA3) in Z797 might contribute to Zn-dependent alleviation of Cd toxicity and enhance its Cd tolerance. Down-regulation of ZIP transporters (TaZIP3, -5, and -7) might contribute to an increase in root Zn concentration and inhibit Cd absorption. Additionally, soil Zn provided an effective strategy for the reduction of grain Cd concentrations in both wheats, with a reduction of 26%â¼32% (high ZnSO4) and 11%â¼67% (high nZnO), respectively. Collectively, these findings provide new insights and perspectives on the mechanisms of Cd mitigation in wheats with different Zn fertilizers and demonstrate that the effect of nZnO in mitigating Cd stress is greater than that of ZnSO4 fertilizers.
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Nanopartículas , Poluentes do Solo , Óxido de Zinco , Humanos , Óxido de Zinco/farmacologia , Cádmio/metabolismo , Zinco/farmacologia , Zinco/metabolismo , Triticum/metabolismo , Fertilizantes , Solo , Proteínas de Membrana Transportadoras/metabolismo , Expressão Gênica , Poluentes do Solo/metabolismoRESUMO
Hierarchically porous magnetic biochar (HMB) had been found to act as an effective amendment to remediate cadmium (Cd) in water and soil in a previous study, but the effects on wheat growth, Cd uptake and translocation mechanisms, and soil microorganisms were unknown. Therefore, soil Cd form transformation, soil enzyme activity, soil microbial diversity, wheat Cd uptake and migration, and wheat growth were explored by adding different amounts of HMB to alkaline Cd-contaminated soil under pot experiments. The results showed that application of HMB (0.5 %-2.0 %) raised soil pH, electrical conductivity (EC) and available Fe concentration, decreased soil available Cd concentration (35.11 %-50.91 %), and promoted Cd conversion to less bioavailable Cd forms. HMB treatments could reduce Cd enrichment in wheat, inhibit Cd migration from root to stem, rachis to glume, glume to grain, and promote Cd migration from stem to leaf and stem to rachis. HMB (0.5 %-1.0 %) boosted antioxidant enzyme activity, reduced oxidative stress, and enhanced photosynthesis in wheat seedlings. Application of 1.0 % HMB increased wheat grain biomass by 40.32 %. Besides, the addition of HMB (0.5 %-1.0 %) could reduce soil Cd bioavailability, increase soil enzyme activity, and increase the abundance and diversity of soil bacteria. Higher soil EC brought forth by HMB (2.0 %) made the wheat plants and soil bacteria poisonous. This study suggests that applying the right amount of HMB to alkaline Cd-contaminated soil could be a potential remediation strategy to decrease Cd in plants' edible parts and enhance soil quality.
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Microbiota , Poluentes do Solo , Cádmio/toxicidade , Cádmio/análise , Solo/química , Triticum , Porosidade , Poluentes do Solo/análise , Carvão Vegetal/química , Grão Comestível/química , Antioxidantes/análise , Fenômenos MagnéticosRESUMO
Calcium (Ca2+) and phosphorous (PO43-) significantly influence the form and effectiveness of nitrogen (N), however, the precise mechanisms governing the adsorption of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) are still lacking. This study employed batch adsorption experiments, charge distribution and multi-site complexation (CD-MUSIC) models and density functional theory (DFT) calculations to elucidate the mechanism by which Ca2+ and PO43- affect the adsorption of NH4+-N and NO3--N on the goethite (GT) surface. The results showed that the adsorption of NH4+-N on the GT exhibited an initial increase followed by a decrease as pH increased, peaking at a pH of 8.5. Conversely, the adsorption of NO3--N decreased with rising pH. According to the CD-MUSIC model, Ca2+ minimally affected the NH4+-N adsorption on the GT but enhanced NO3--N adsorption via electrostatic interaction, promoting the adsorption of ≡FeOH-NO3- and ≡Fe3O-NO3- species. Similarly, PO43- inhibited the adsorption of ≡FeOH-NO3- and ≡Fe3O-NO3- species. However, PO43- boosted NH4+-N adsorption by facilitating the formation of ≡Fe3O-NH4+ via electrostatic interaction and site competition. DFT calculations indicates that although bidentate phosphate (BP) was beneficial to stabilize NH4+-N than monodentate phosphate (SP), SP-NH4+ was the main adsorption configuration at pH 5.5-9.5 owing the prevalence of SP on the GT surface under site competition of NH4+-N. The results of CD-MUSIC model and DFT calculation were verified mutually, and provide novel insights into the mechanisms underlying N fixation and migration in soil.
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Compostos de Amônio , Cálcio , Teoria da Densidade Funcional , Nitratos , Nitrogênio , Fósforo , Adsorção , Cálcio/química , Nitrogênio/química , Fósforo/química , Nitratos/química , Compostos de Amônio/química , Compostos Férricos/química , Modelos Químicos , Concentração de Íons de HidrogênioRESUMO
A possible mechanism for the improved availability of zinc (Zn) in soil by combining nitrogen (N) with Zn supply was investigated based on the root exudates of winter wheat. N, Zn supply as well as their combination significantly regulated nine root exudates in winter wheat; in which, the secretion of cis-aconitic acid involving in the TCA cycle, C5-branched dibasic acid metabolism, glyoxylate and dicarboxylate metabolism and 2-oxocarboxylic acid metabolism was upregulated by N, Zn supply as well as their combination. N-Zn combination induced the activities of citrate synthase and cis-aconitase in roots and shoots of winter wheat thus to increase the concentrations of citric and aconitic acid; the decrease of isocitric acid concentrations in shoots indicated the inhibited conversion of aconitic acid to isocitric acid by N-Zn combination. It revealed a possible reason for the enhanced secretion of cis-aconitic acid by N-Zn combination. Exogenous addition of 10 µ plant-1 cis-aconitate significantly increased available Zn concentrations in soil and Zn concentrations in winter wheat under N-Zn combination. Thus, the N-Zn combination regulated the metabolism of cis-aconitic acid in winter wheat, thus enhancing the secretion of cis-aconitic acid to increase the bioavailability of Zn in soil.
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Triticum , Zinco , Zinco/metabolismo , Triticum/metabolismo , Solo , Nitrogênio/metabolismo , Ácido Aconítico , Exsudatos e Transudatos/metabolismoRESUMO
Although the autopsies of reverse osmosis (RO) membranes from full-scale, brackish water desalination plants identify the co-presence of silica and Ca-based minerals in scaling layers, minimal research exists on their formation process and mechanisms. Therefore, combined scaling by silica and either gypsum (non-alkaline) or amorphous calcium phosphate (ACP, alkaline) was investigated in this study for their distinctive impacts on membrane performance. The obtained results demonstrate that the coexistence of silica and Ca-based mineral salts in feedwaters significantly reduced water flux decline as compared to single type of Ca-based mineral salts. This antagonistic effect was primarily attributed to the silica-mediated alleviation of Ca-based mineral scaling. In the presence of silica, silica skins were immediately established around Ca-based mineral precipitates once they emerged. Sheathing by the siliceous skins hindered the aggregation and thus the morphological evolution of Ca-based mineral species. Unlike sulfate precipitates, ACP precipitates can induce the formation of dense and thick silica skins via an additional condensation reaction. Such a phenomenon rationalized the notion concerning a stronger mitigating effect of silica on ACP scaling than gypsum scaling. Meanwhile, coating by silica skins altered the surface chemistries of Ca-based mineral precipitates, which should be fully considered in regulating membrane surface properties for combined scaling control. Our findings advance the mechanistic understanding on combined mineral scaling of RO membranes, and may guide the appropriate design of membrane surface properties for scaling-resistant membrane tailored to brackish water desalination.
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Dióxido de Silício , Purificação da Água , Cálcio , Sulfato de Cálcio , Sais , Purificação da Água/métodos , Osmose , Minerais , Águas Salinas , Membranas ArtificiaisRESUMO
The hormetic response of microbes to cadmium (Cd) is often observed in soil, but the mechanisms are unclear. In this study, we proposed a novel perspective of hormesis that successfully explained the temporal hermetic response of soil enzymes and microbes, and the variation of soil physicochemical properties. Several soil enzymatic and microbial activities were stimulated by 0.5 mg·kg-1 exogenous Cd, but inhibited at higher Cd dosages. The phenomena suggested the hormetic response to 0.5 mg·kg-1 Cd was highly generalizable concerning soil enzymes and microbial activity. However, the response disappeared after incubation for >10 days. Soil respiration was also initially enhanced by exogenous Cd and decreased after consumption of labile soil organic matter. The metagenomic results revealed Cd stimulation of genes involved in labile soil organic matter decomposition. Additionally, Cd enriched the antioxidant enzymatic activity and abundances of the corresponding marker genes, rather than genes involved in the efflux-mediated heavy metal resistance. The microbes enhanced their primary metabolism to make up the energy gaps, with hormesis evident. The hormetic response disappeared after the labile compounds in soil were exhausted. Overall, this study illustrates the dose-dependence and temporal variation of stimulants and provides a novel and feasible strategy for the study of Cd in soil microorganisms.
Assuntos
Metais Pesados , Poluentes do Solo , Cádmio/análise , Hormese , Solo/química , Poluentes do Solo/análise , Microbiologia do SoloRESUMO
Over the years, microbial community composition in the rhizosphere has been extensively studied as the most fascinating topic in microbial ecology. In general, plants affect soil microbiota through rhizodeposits and changes in abiotic conditions. However, a consensus on the response of microbiota traits to the rhizosphere and bulk soils in various ecosystems worldwide regarding community diversity and structure has not been reached yet. Here, we conducted a meta-analysis of 101 studies to investigate the microbial community changes between the rhizosphere and bulk soils across various plant species (maize, rice, vegetables, other crops, herbaceous, and woody plants). Our results showed that across all plant species, plant rhizosphere effects tended to reduce the rhizosphere soil pH, especially in neutral or slightly alkaline soils. Beta-diversity of bacterial community was significantly separated between into rhizosphere and bulk soils. Moreover, r-strategists and copiotrophs (e.g. Proteobacteria and Bacteroidetes) enriched by 24-27% in the rhizosphere across all plant species, while K-strategists and oligotrophic (e.g. Acidobacteria, Gemmatimonadete, Nitrospirae, and Planctomycetes) decreased by 15-42% in the rhizosphere. Actinobacteria, Firmicutes, and Chloroflexi are also depleted by in the plant rhizosphere compared with the bulk soil by 7-14%. The Actinobacteria exhibited consistently negative effect sizes across all plant species, except for maize and vegetables. In Firmicutes, both herbaceous and woody plants showed negative responses to rhizosphere effects, but those in maize and rice were contrarily enriched in the rhizosphere. With regards to Chloroflexi, apart from herbaceous plants showing a positive effect size, the plant rhizosphere effects were consistently negative across all other plant types. Verrucomicrobia exhibited a significantly positive effect size in maize, whereas herbaceous plants displayed a negative effect size in the rhizosphere. Overall, our meta-analysis exhibited significant changes in microbial community structure and diversity responding to the plant rhizosphere effects depending on plant species, further suggesting the importance of plant rhizosphere to environmental changes influencing plants and subsequently their controls over the rhizosphere microbiota related to nutrient cycling and soil health.