RESUMO
In this study, two wheat-derived cadmium (Cd)-immobilizing endophytic Pseudomonas paralactis M14 and Priestia megaterium R27 were evaluated for their effects on wheat tissue Cd uptake under hydroponic conditions. Then, the impacts of the biochar (BC), M14+R27 (MR), and BC+MR treatments on wheat Cd uptake and the mechanisms involved were investigated at the jointing, heading, and mature stages of wheat plants under field-plot conditions. A hydroponic experiment showed that the MR treatment significantly decreased the above-ground tissue Cd content compared with the M14 or R27 treatment. The BC+MR treatment reduced the grain Cd content by 51.5%-67.7% and Cd translocation factor at the mature stage of wheat plants and increased the organic matter-bound Cd content by 31%-75% in the rhizosphere soils compared with the BC or MR treatment. Compared with the BC or MR treatment, the relative abundances of the biomarkers associated with Gemmatimonas, Altererythrobacter, Gammaproteobacteria, Xanthomonadaceae, Phenylobacterium, and Nocardioides in the BC+MR-treated rhizosphere microbiome decreased and negatively correlated with the organic matter-bound Cd contents. In the BC+MR-treated root interior microbiome, the relative abundance of the biomarker belonging to Exiguobacterium increased and negatively correlated with the Cd translocation factor, while the relative abundance of the biomarker belonging to Pseudonocardiaceae decreased and positively correlated with the Cd translocation factor. Our findings suggested that the BC+MR treatment reduced Cd availability and Cd transfer through affecting the abundances of these specific biomarkers in the rhizosphere soil and root interior microbiomes, leading to decreased wheat grain Cd uptake in the contaminated soil.
Assuntos
Cádmio , Carvão Vegetal , Microbiologia do Solo , Poluentes do Solo , Triticum , Triticum/metabolismo , Triticum/microbiologia , Cádmio/metabolismo , Poluentes do Solo/metabolismo , Endófitos/fisiologia , Rizosfera , Solo/química , Biodegradação Ambiental , Microbiota/efeitos dos fármacosRESUMO
Pollution accident of nonferrous metallurgy industry often lead to serious heavy metal pollution of the surrounding soil. Phytoremediation of contaminated soil is an environmental and sustainable technology, and soil native microorganisms in the process of phytoremediation also participate in the remediation of heavy metals. However, the effects of high concentrations of multiple heavy metals (HCMHMs) on plants and native soil microorganisms remain uncertain. Thus, further clarification of the mechanism of phytoremediation of HCMHMs soil by plants and native soil microorganisms is required. Using the plant Sedum alfredii (S. alfredii) to restore HCMHM-contaminated soil, we further explored the mechanism of S. alfredii and native soil microorganisms in the remediation of HCMHM soils. The results showed that (i) S. alfredii can promote heavy metals from non-rhizosphere soil to rhizosphere soil, which is conducive to the effect of plants on heavy metals. In addition, it can also enrich the absorbed heavy metals in its roots and leaves; (ii) native soil bacteria can increase the abundance of signal molecule-synthesizing enzymes, such as trpE, trpG, bjaI, rpfF, ACSL, and yidC, and promote the expression of the pathway that converts serine to cysteine, then synthesize substances to chelate heavy metals. In addition, we speculated that genes such as K19703, K07891, K09711, K19703, K07891, and K09711 in native bacteria may be involved in the stabilization or absorption of heavy metals. The results provide scientific basis for S. alfredii to remediate heavy metals contaminated soils, and confirm the potential of phytoremediation of HCMHM contaminated soil.
Assuntos
Biodegradação Ambiental , Metais Pesados , Sedum , Microbiologia do Solo , Poluentes do Solo , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Sedum/metabolismo , Metais Pesados/análise , Rizosfera , Solo/químicaRESUMO
Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened. The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II) and Mn(II) by Pseudomonas taiwanensis (marked as P4) and Pseudomonas plecoglossicida (marked as G1) contains rich reactive oxygen functional groups, which play critical roles in the removal efficiency and immobilization of heavy metal(loid)s in co-contamination system. The isolated strains P4 and G1 can grow well in the following environments: pH 5-9, NaCl 0-4%, and temperature 20-30°C. The removal efficiencies of Fe, Pb, As, Zn, Cd, Cu, and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system (the initial concentrations of heavy metal(loid) were 1 mg/L), approximately reaching 96%, 92%, 85%, 67%, 70%, 54% and 15%, respectively. The exchangeable and carbonate bound As, Cd, Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil, thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s. This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.
Assuntos
Metais Pesados , Poluentes do Solo , Poluentes Químicos da Água , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/análise , Poluentes do Solo/metabolismo , Oxirredução , Pseudomonas/metabolismo , Manganês , Ferro/química , Ferro/metabolismo , Solo/química , Biodegradação Ambiental , Microbiologia do SoloRESUMO
Harnessing bacteria for superoxide production in bioremediation holds immense promise, yet its practical application is hindered by slow production rates and the relatively weak redox potential of superoxide. This study delves into a cost-effective approach to amplify superoxide production using an Arthrobacter strain, a prevalent soil bacterial genus. Our research reveals that introducing a carbon source along with specific iron-binding ligands, including deferoxamine (DFO), diethylenetriamine pentaacetate (DTPA), citrate, and oxalate, robustly augments microbial superoxide generation. Moreover, our findings suggest that these iron-binding ligands play a pivotal role in converting superoxide into hydroxyl radicals by modulating the electron transfer rate between Fe(III)/Fe(II) and superoxide. Remarkably, among the tested ligands, only DTPA emerges as a potent promoter of this conversion process when complexed with Fe(III). We identify an optimal Fe(III) to DTPA ratio of approximately 1:1 for enhancing hydroxyl radical production within the Arthrobacter culture. This research underscores the efficacy of simultaneously introducing carbon sources and DTPA in facilitating superoxide production and its subsequent conversion to hydroxyl radicals, significantly elevating bioremediation performance. Furthermore, our study reveals that DTPA augments superoxide production in cultures of diverse soils, with various soil microorganisms beyond Arthrobacter identified as contributors to superoxide generation. This emphasizes the universal applicability of DTPA across multiple bacterial genera. In conclusion, our study introduces a promising methodology for enhancing microbial superoxide production and its conversion into hydroxyl radicals. These findings hold substantial implications for the deployment of microbial reactive oxygen species in bioremediation, offering innovative solutions for addressing environmental contamination challenges.
Assuntos
Arthrobacter , Biodegradação Ambiental , Radical Hidroxila , Ferro , Superóxidos , Radical Hidroxila/metabolismo , Superóxidos/metabolismo , Arthrobacter/metabolismo , Ferro/metabolismo , Ligantes , Microbiologia do Solo , Poluentes do Solo/metabolismo , Desferroxamina/metabolismoRESUMO
The land application of livestock manure has been widely acknowledged as a beneficial approach for nutrient recycling and environmental protection. However, the impact of residual antibiotics, a common contaminant of manure, on the degradation of organic compounds and nutrient release in Eutric Regosol is not well understood. Here, we studied, how oxytetracycline (OTC) and ciprofloxacin (CIP) affect the decomposition, microbial community structure, extracellular enzyme activities and nutrient release from cattle and pig manure using litterbag incubation experiments. Results showed that OTC and CIP greatly inhibited livestock manure decomposition, causing a decreased rate of carbon (28%-87%), nitrogen (15%-44%) and phosphorus (26%-43%) release. The relative abundance of gram-negative (G-) bacteria was reduced by 4.0%-13% while fungi increased by 7.0%-71% during a 28-day incubation period. Co-occurrence network analysis showed that antibiotic exposure disrupted microbial interactions, particularly among G- bacteria, G+ bacteria, and actinomycetes. These changes in microbial community structure and function resulted in decreased activity of urease, ß-1,4-N-acetyl-glucosaminidase, alkaline protease, chitinase, and catalase, causing reduced decomposition and nutrient release in cattle and pig manures. These findings advance our understanding of decomposition and nutrient recycling from manure-contaminated antibiotics, which will help facilitate sustainable agricultural production and soil carbon sequestration.
Assuntos
Antibacterianos , Gado , Esterco , Microbiologia do Solo , Animais , Solo/química , Sequestro de Carbono , Carbono/metabolismo , Fósforo , Reciclagem , Poluentes do Solo/metabolismo , Bovinos , Suínos , Nitrogênio/análise , OxitetraciclinaRESUMO
Soil and wastewater samples contaminated by petroleum-related industries were collected from various locations in Saudi Arabia, a country known for its vast oil reserves. The samples were analyzed for their physicochemical properties, including the presence of metals, petroleum hydrocarbons, and aromatic compounds. A total of 264 fungal isolates were analyzed and categorized into eight groups of Aspergillus (194 isolates) and four groups of Penicillium (70 isolates). The potential of these fungal groups to grow in oil or its derivatives was investigated. Two isolates, Aspergillus tubingensis FA-KSU5 and A. niger FU-KSU69, were utilized in two remediation experiments-one targeting wastewater and the other focusing on polluted soil. The FA-KSU5 strain demonstrated complete removal of Fe3+, As3+, Cr6+, Zn2+, Mn2+, Cu2+ and Cd2+, with bioremediation efficiency for petroleum hydrocarbons in the wastewater from these sites ranging between 90.80 and 98.58%. Additionally, the FU-KSU69 strain achieved up to 100% reduction of Co2+, Ba2+, B3+, V+, Ni2+, Pb2+ and Hg2+, with removal efficiency ranging from 93.17 to 96.02% for aromatic hydrocarbons after 180 min of wastewater treatment. After 21 days of soil incubation with Aspergillus tubingensis FA-KSU5, there was a 93.15% to 98.48% reduction in total petroleum hydrocarbons (TPHs) and an 88.11% to 97.31% decrease in polycyclic aromatic hydrocarbons (PAHs). This strain exhibited the highest removal rates for Cd2+ and As3+ followed by Fe3+, Zn2+, Cr6+, Se4+ and Cu2+. Aspergillus niger FU-KSU69 achieved a 90.37% to 94.90% reduction in TPHs and a 95.13% to 98.15% decrease in PAHs, with significant removal of Ni2+, Pb2+ and Hg2+, followed by Co2+, V+, Ba2+ and B3+. The enzymatic activity in the treated soils increased by 1.54- to 3.57-fold compared to the polluted soil. Although the mixture of wastewater and polluted soil exhibited high cytotoxicity against normal human cell lines, following mycoremediation, all treated soils and effluents with the dead fungal biomass showed no toxicity against normal human cell lines at concentrations up to 500 µL/mL, with IC50 values ≥ 1000 µL/mL. SEM and IR analysis revealed morphological and biochemical alterations in the biomass of A. tubingensis FA-KSU5 and A. niger FA-KSU69 when exposed to petroleum effluents. This study successfully introduces non-toxigenic and environmentally friendly fungal strains play a crucial role in the bioremediation of contaminated environments. Both strains serve as low-cost and effective adsorbents for bio-remediating petroleum wastewater and oil-contaminated soil. Heavy metals and hydrocarbons, the primary pollutants, were either completely removed or reduced to permissible levels according to international guidelines using the dead biomass of FA-KSU5 and FA-KSU69 fungi. Consequently, the environments associated with this globally significant industry are rendered biologically safe, particularly for humans, as evidenced by the absence of cytotoxicity in samples treated with A. tubingensis FA-KSU5 and A. niger FA-KSU69 on various human cell types.
Assuntos
Aspergillus , Biodegradação Ambiental , Petróleo , Microbiologia do Solo , Poluentes do Solo , Águas Residuárias , Águas Residuárias/microbiologia , Águas Residuárias/química , Petróleo/metabolismo , Poluentes do Solo/metabolismo , Aspergillus/metabolismo , Aspergillus/isolamento & purificação , Aspergillus/crescimento & desenvolvimento , Aspergillus/classificação , Penicillium/metabolismo , Penicillium/isolamento & purificação , Arábia Saudita , Poluição por Petróleo , Fungos/metabolismo , Fungos/classificação , Fungos/isolamento & purificação , Metais/metabolismo , Solo/química , Hidrocarbonetos/metabolismoRESUMO
This study evaluated the responses of sweet potatoes to Cadmium (Cd) stress through pot experiments to theoretically substantiate their comprehensive applications in Cd-polluted agricultural land. The experiments included a CK treatment and three Cd stress treatments with 3, 30, and 150 mg/kg concentrations, respectively. We analyzed specified indicators of sweet potato at different growth periods, such as the individual plant growth, photosynthesis, antioxidant capacity, and carbohydrate Cd accumulation distribution. On this basis, the characteristics of the plant carbon metabolism in response to Cd stress throughout the growth cycle were explored. The results showed that T2 and T3 treatments inhibited the vine growth, leaf area expansion, stem diameter elongation, and tuberous root growth of sweet potato; notably, T3 treatment significantly increased the number of sweet potato branches. Under Cd stress, the synthesis of chlorophyll in sweet potato was significantly suppressed, and the Rubisco activity experienced significant reductions. With the increasing Cd concentration, the function of PS II was also affected. The soluble sugar content underwent no significant change in low Cd concentration treatments. In contrast, it decreased significantly under high Cd concentrations. Additionally, the tuberous root starch content decreased significantly with the increase in Cd concentration. Throughout the plant growth, the activity levels of catalase, peroxidase, and superoxide dismutase increased significantly in T2 and T3 treatments. By comparison, the superoxide dismutase activity in T1 treatment was significantly lower than that of CK. With the increasing application of Cd, its accumulation accordingly increased in various sweet potato organs. The the highest bioconcentration factor was detected in absorbing roots, while the tuberous roots had a lower bioconcentration factor and Cd accumulation. Moreover, the transfer factor from stem to petiole was the highest of the potato organs. These results demonstrated that sweet potatoes had a high Cd tolerance and a restoration potential for Cd-contaminated farmland.
Assuntos
Cádmio , Ipomoea batatas , Fotossíntese , Ipomoea batatas/crescimento & desenvolvimento , Ipomoea batatas/efeitos dos fármacos , Ipomoea batatas/metabolismo , Ipomoea batatas/fisiologia , Cádmio/toxicidade , Cádmio/metabolismo , Fotossíntese/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Clorofila/metabolismo , Antioxidantes/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Poluentes do Solo/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismoRESUMO
This study investigates the phytoremediation potential of non-productive seedlings of Ailanthus altissima, Acer pseudoplatanus, and Fraxinus excelsior for lead, cadmium, and zinc accumulation in contaminated soils of Zanjan Province, an industrial area with significant pollution. The evaluation employed a completely randomized design, with three treatment levels for each element, alongside a control treatment, replicated three times over a two-year period. A total of 810 one-year-old seedlings from the three species were involved in the study. Soil contamination levels, ranging from 0 to 2000 mg/kg for lead and zinc and from 0 to 200 mg/kg for cadmium, were administered through soil pot irrigation. Sampling of seedling stems and pot soils was conducted in November of 2021 and 2022. The absorption levels of elements in the samples were determined using the dry acid digestion method and an ICP-OES atomic absorption spectrometer. Results indicate species-specific variations in metal absorption, with Ailanthus showing the highest accumulation rates. Findings suggest Ailanthus as a promising candidate for soil improvement in polluted environments, particularly in contaminated soils of Zanjan Province.
Assuntos
Acer , Ailanthus , Biodegradação Ambiental , Fraxinus , Metais Pesados , Plântula , Poluentes do Solo , Poluentes do Solo/metabolismo , Poluentes do Solo/análise , Fraxinus/metabolismo , Ailanthus/metabolismo , Metais Pesados/metabolismo , Metais Pesados/análise , Acer/metabolismo , Plântula/metabolismo , Solo/química , Zinco/metabolismo , Zinco/análise , Cádmio/metabolismo , Cádmio/análise , Chumbo/metabolismo , Chumbo/análiseRESUMO
Heavy metals have been recognized as a prominent hazard in today's world, causing pollution in the air environment. Woody tree species can play a significant role in the extraction and remediation of metal pollutants from the air, therefore promoting the air quality index. This study investigated the potential of four species of the Ficus genus (F. benjamina, F. microcarpa, F. religiosa, and F. virens) to remediate varying levels of heavy metal contamination in industrial, residential, and highway areas of Faisalabad City, Pakistan. For this purpose, six heavy metals (cadmium, chromium, copper, lead, zinc, and manganese) were assessed in young leaves (YL) as well as old leaves (OL) of subjected tree species at selected study sites. Eight fully expanded leaves were selected from each tree species: two from each cardinal direction from the shoot of the current year (young leaves, YL), as well as from the shoot of the previous year (old leaves, OL). The results showed that the same genus has different capabilities to accumulate different heavy metals, and the overall trend was in the following order: F. virens > F. religiosa > F. benjamina > F. microcarpa at all study sites. The heavy metal contents in both YL and OL of selected tree species decreased in the order of Manganese (Mn)> Zinc (Zn)> Copper (Cu) > Chromium (Cr) > Lead (Pb) > Cadmium (Cd) at all study sites. The metal accumulation index (MAI) values ranged between 2.14-5.42 for F. benjamina, 2.09-3.89 for F. microcarpa, 3.61-7.01 for F. religiosa and 4.77-6.48 for F. virens across all study sites. Among the studied tree species, it has been determined that F. virens and F. religiosa are well-suited for urban areas with significant heavy metal contamination and can be strategically planted in barrier areas to effectively combat atmospheric pollution.
Assuntos
Biodegradação Ambiental , Ficus , Metais Pesados , Folhas de Planta , Ficus/metabolismo , Ficus/química , Metais Pesados/análise , Metais Pesados/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/química , Paquistão , Poluentes do Solo/análise , Poluentes do Solo/metabolismoRESUMO
Considering the toxicological effects of some heavy metals (HMs) in which directly related to mortality and carcinogenicity in the population by their entrance from plants through livestock grazing, and medical skin cream, the rehabilitation of contaminated sites through phytoremediation by native plants might be quite challenging. Diplotaenia damavandica Mozaff. ex-Hedge & Lamond, is used as medical skin creams due to the existence of specific ingredients, which can be effective in treating skin disease. In the present study, the plant and associated soil sampling were performed around the boundary of D. damavandica. The concentration was measured using the Inductively coupled plasma mass spectrometry (ICP-MS). The results revealed the effect of existing endemic plants on reducing the average concentration of lead and zinc in soil by 40 and 60%, respectively, due to phytoremediation. EDX confirmed the presence of Pb and Zn in root and shoot tissues. Based on the results of this study, D. damavandica is an endemic perennial herbaceous plant with 60% biomass and prosperous root systems, which can grow in low contaminated areas of Pb in the southeast of Damavand Mt. Hence, the HMs pattern indicated less often in the aerial parts except for lead, which should be examined more carefully for skin cream uses.
Assuntos
Biodegradação Ambiental , Metais Pesados , Poluentes do Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Poluentes do Solo/metabolismo , Metais Pesados/análise , Metais Pesados/metabolismo , Metais Pesados/toxicidade , Irã (Geográfico) , Solo/química , Chumbo/toxicidade , Chumbo/análise , Chumbo/metabolismo , Humanos , Zinco/análise , Zinco/metabolismo , Zinco/toxicidade , Monitoramento Ambiental/métodos , Raízes de Plantas/metabolismo , Raízes de Plantas/químicaRESUMO
Imidacloprid (IDP) is an active ingredient of the Admire brand pesticide used to control the vector (Asian citrus psyllid) that transmits the causative organism Candidatus Liberibacter asiaticus (CLas) for citrus greening or huanglongbing disease. Imidacloprid products are applied via soil drench where citrus roots are mostly concentrated which is between 0 and 60 cm depth. These soil depths exhibit different characteristics that may affect IDP leaching beyond the rooting zone. Representative soil samples were collected from Entisols and Ultisols, which are the dominant soil orders under citrus production in central Florida, at 15 cm increments up to 60 cm to estimate and understand the batch sorption, kinetics, equilibria, and degradation of IDP. Results showed that the equilibrium time for IDP at 0-15 cm depth (10 hours) was 2 times faster than at 15-60 cm (20 hours) for the Entisol. Nevertheless, all depths reached equilibrium within 24 hours for the Entisol. The 0-30 cm depth adsorbed 2 times more IDP than the 30-60 cm depth for both soils. Nevertheless, the adsorption coefficient was approximately ≤ 1 mL g-1 for both soils. The half-life of IDP in both soils ranged from 10 to 17 days. The Entisol showed higher adsorption than the Ultisol at both depths, probably due to relatively lower organic carbon (OC) content in the Ultisol compared to the Entisol. Thus, the Ultisol showed high IDP leaching vulnerability compared to the Entisol. Movement of IDP is affected by the amount of OC in the citrus critical zone.
Assuntos
Citrus , Neonicotinoides , Nitrocompostos , Poluentes do Solo , Solo , Neonicotinoides/química , Neonicotinoides/metabolismo , Nitrocompostos/química , Nitrocompostos/metabolismo , Florida , Solo/química , Adsorção , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Citrus/química , Cinética , Meia-Vida , Inseticidas/química , Inseticidas/metabolismo , Imidazóis/química , Imidazóis/metabolismoRESUMO
The risk of arsenic contamination is rising globally, and it has negative impacts on the physiological processes and growth of plants. Metal removal from contaminated soils can be accomplished affordably and effectively with plant growth promoting rhizobacteria (PGPR)-based microbial management. From this angle, this research evaluated the mitigation of arsenic toxicity using the bacteria isolated from contaminated site, Mettur, Salem district, South India. The newly isolated bacterial strain was screened for plant growth promotion potential and arsenic tolerance such as (100 ppm, 250 ppm, 500 ppm, 800 ppm and 1200 ppm). The metal tolerant rhizobacteria was identified using 16S rRNA gene sequence analysis as Pseudomonas alcaliphila strain PAS1 (GenBank accession number: OQ804624). Pigeon pea (Cajanus cajan) plants were used in pot culture experiments with varying concentrations of arsenic, (5 ppm, 10 ppm and 25 ppm) both with and without bacterial culture, for a period of 45 days. At the concentration of 25 ppm after the application of PAS1 enhanced the plant growth, protein and carbohydrate by 35.69%, 18.31% respectively. Interestingly, P. alcaliphila strain PAS1 significantly reduced the stress-induced elevated levels of proline, flavonoid, phenol and antioxidant enzyme in pigeon pea plants was 40%, 31.11%, 27.80% and 20.12%, respectively. Consequently, PAS1 may significantly reduce the adverse effects that arsenic causes to plant development in acidic soils, improve plant uptake of nutrients, and increase plant production. The findings of this study reveal that P. alcaliphila PAS1 is intrinsic for phytoremediation by reducing arsenic accumulation in the root and shoot.
Assuntos
Arsênio , Biodegradação Ambiental , Cajanus , Metais Pesados , Pseudomonas , Microbiologia do Solo , Poluentes do Solo , Cajanus/microbiologia , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidade , Pseudomonas/metabolismo , Metais Pesados/toxicidade , Arsênio/metabolismo , Arsênio/toxicidade , RNA Ribossômico 16S/genética , Índia , Raízes de Plantas/microbiologiaRESUMO
There is a long-standing debate over the effectiveness of chemical extraction methods in assessing soil metal phytoavailability. This study addresses the limitations of widely-used chemical extraction methods and presents the water-extractable pool as a more reliable indicator based on wheat pot experiments using homogenized agricultural soil amended with lime materials, phosphate, and biochar. Over 120 days' pot experiments, Cd accumulation in whole wheat plants and tissues exhibited positive relationships with water-extractable Cd concentrations at heading and maturity stage (Spearman's rho: 0.521-0.851; P < 0.05), revealing that the water-extractable pool instead of other pools better indicates wheat metal accumulation. Water-extractable metal concentrations are effective in assessing phytoavailability of metals primarily in ionic forms in soil solution (e.g, Zn, Cd), but less reliable for metals strongly complexed with dissolved organic matter (DOM) or sensitive to redox conditions. It demonstrated that water-extractable metal concentrations and chemical forms are key factors, fundamentally determined by metal properties and impacted by environmental factors. This study clarifies a more direct link between chemical extraction and plant metal uptake mechanisms. Given the extensive application of chemical extraction methods over several decades, this study will help advance soil metal risk assessment and remediation practices.
Assuntos
Metais Pesados , Poluentes do Solo , Triticum , Água , Triticum/metabolismo , Triticum/química , Poluentes do Solo/metabolismo , Poluentes do Solo/química , Metais Pesados/metabolismo , Metais Pesados/química , Água/química , Óxidos/química , Compostos de Cálcio/química , Carvão Vegetal/química , Solo/químicaRESUMO
Although extensive research has been conducted on the environmental impact of microplastics (MPs), their effects on microorganisms during the composting process and on the compost-soil system remain unclear. Our research investigates the microbial response to polylactic acid microplastics (PLAMPs) during aerobic composting and examines how compost enriched with PLAMPs affects plants. Our findings reveal that PLAMPs play a dual role in the composting process, influencing microorganisms differently depending on the composting phase. PLAMPs reduce the relative abundance of sensitive bacterial ASVs, specifically those belonging to Limnochordaceae and Enterobacteriaceae, during composting, while increasing the relative abundance of ASVs belonging to Steroidobacteriaceae and Bacillaceae. The impact of PLAMPs on microbial community assembly and niche width was found to be phase-dependent. In the stabilization phase (S5), the presence of PLAMPs caused a shift in the core microbial network from bacterial dominance to fungal dominance, accompanied by heightened microbial antagonism. Additionally, these intricate microbial interactions can be transferred to the soil ecosystem. Our study indicates that composting, as a method of managing PLAMPs, is also influenced by PLAMPs. This influence is transferred to the soil through the use of compost, resulting in severe oxidative stress in plants. Our research is pivotal for devising future strategies for PLAMPs management and predicting the subsequent changes in compost quality and environmental equilibrium.
Assuntos
Bactérias , Compostagem , Microplásticos , Poliésteres , Microbiologia do Solo , Poluentes do Solo , Microplásticos/toxicidade , Poliésteres/metabolismo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Poluentes do Solo/metabolismo , Bactérias/metabolismo , Bactérias/classificação , Ecossistema , Microbiota/efeitos dos fármacos , Fungos/metabolismo , Solo/química , Plantas/metabolismo , Plantas/efeitos dos fármacosRESUMO
Assessing the bioaccessibility and bioavailability of cadmium (Cd) is crucial for effective evaluation of the exposure risk associated with intake of Cd-contaminated rice. However, limited studies have investigated the influence of gut microbiota on these two significant factors. In this study, we utilized in vitro gastrointestinal simulators, specifically the RIVM-M (with human gut microbial communities) and the RIVM model (without gut microbial communities), to determine the bioaccessibility of Cd in rice. Additionally, we employed the Caco-2 cell model to assess bioavailability. Our findings provide compelling evidence that gut microbiota significantly reduces Cd bioaccessibility and bioavailability (p<0.05). Notably, strong in vivo-in vitro correlations (IVIVC) were observed between the in vitro bioaccessibilities and bioavailabilities, as compared to the results obtained from an in vivo mouse bioassay (R2 = 0.63-0.65 and 0.45-0.70, respectively). Minerals such as copper (Cu) and iron (Fe) in the food matrix were found to be negatively correlated with Cd bioaccessibility in rice. Furthermore, the results obtained from the toxicokinetic (TK) model revealed that the predicted urinary Cd levels in the Chinese population, based on dietary Cd intake adjusted by in vitro bioaccessibility from the RIVM-M model, were consistent with the actual measured levels (p > 0.05). These results indicated that the RIVM-M model represents a potent approach for measuring Cd bioaccessibility and underscore the crucial role of gut microbiota in the digestion and absorption process of Cd. The implementation of these in vitro methods holds promise for reducing uncertainties in dietary exposure assessment.
Assuntos
Disponibilidade Biológica , Cádmio , Microbioma Gastrointestinal , Oryza , Oryza/metabolismo , Cádmio/metabolismo , Humanos , Animais , Camundongos , Células CACO-2 , Contaminação de Alimentos/análise , Poluentes do Solo/metabolismo , Poluentes do Solo/análiseRESUMO
Combined Cd (cadmium) and As (arsenic) pollution in cultivated land affects the safety of crops production and endangers human health. Rice (Oryza sativa L.) is a crop that uptakes Si (silicon), and Si can effectively promote rice growth and mitigate heavy metal toxicity. This study examined the effect and mechanism of Si-rich amendment (HA) prepared by aerobic combustion of rice husk on Cd and As accumulation in iron plaque and rice seedlings via hydroponic experiments. HA enhanced the vitality of rice growth because of its Si content and increased the amount of amorphous fraction iron plaques, furthermore, Cd content was decreased while the As was increased in both amorphous fraction and crystalline fraction iron plaques, resulting in the contents of Cd and As decreases by 10.0%-38.3% and 9.6%-42.8% for the shoots, and by 13.4%-45.2% and 9.9%-20.0% for the roots, respectively. In addition, X-ray diffraction and X-ray photoelectron spectroscopy illustrated significantly more Fe2O, MnO2 and MnO in the iron plaque after HA supply and the simultaneous existence of Mn-As and Mn-Si compounds. This result revealed less Cd from iron plaque and more As retention with HA supply, reducing the amount of Cd and As up taking and accumulation by rice seedlings. HA is beneficial to rice growth and reduce the absorption of heavy metals in plants. At the same time, HA is environmentally friendly, it can be used for the remediation of paddy fields contaminated by Cd and As.
Assuntos
Arsênio , Cádmio , Ferro , Oryza , Plântula , Silício , Poluentes do Solo , Oryza/metabolismo , Oryza/crescimento & desenvolvimento , Cádmio/metabolismo , Arsênio/metabolismo , Ferro/metabolismo , Plântula/metabolismo , Plântula/crescimento & desenvolvimento , Silício/metabolismo , Poluentes do Solo/metabolismo , Raízes de Plantas/metabolismo , Solo/químicaRESUMO
The relationship between plants and soil microbial communities is complex and subtle, with microbes playing a crucial role in plant growth. Autochthonous bioaugmentation and nutrient biostimulation are promising bioremediation methods for herbicides in contaminated agricultural soils, but how microbes interact to promote biodegradation and plant growth on barren fields, especially in response to the treatment of the herbicide bromoxynil after wheat seedlings, remains poorly understood. In this study, we explored the microbial community reassembly process from the three-leaf stage to the tillering stage of wheat and put forward the idea of using the overlapping results of three methods (network Zi-Pi analysis, LEfSe analysis, and Random Forest analysis) as keystones for the simplification and optimization of key microbial species in the soil. Then we used genome-scale metabolic models (GSMMs) to design a targeted synthetic microbiome for promoting wheat seedling growing. The results showed that carbon source was more helpful in enriching soil microbial diversity and promoting the role of functional microbial communities, which facilitated the degradation of bromoxynil. Designed a multifunctional synthetic consortium consisting of seven non-degraders which unexpectedly assisted in the degradation of indigenous bacteria, which increased the degradation rate of bromoxynil by 2.05 times, and when adding nutritional supplementation, it increased the degradation rate by 3.65 times. In summary, this study provides important insights for rational fertilization and precise microbial consortium management to improve plant seedling growth in contaminated fields.
Assuntos
Biodegradação Ambiental , Microbiota , Microbiologia do Solo , Poluentes do Solo , Triticum , Poluentes do Solo/metabolismo , Herbicidas/metabolismoRESUMO
The rare earth element lanthanum (La(III)) has been found to effectively enhance crop yields and improve plant growth and development. Arsenic (As), as a class of toxic metals widely found in the environment, poses a serious threat to both ecological and human health. Research on the application of La(III) in phytoremediation to enhance remediation efficiency is currently lacking. This study examined the impact of La(III) on physiological and biochemical indicators of Solanum nigrum L. (S. nigrum) exposed to Sodium hydrogen arsenate (SA) and Roxarsone (ROX) treatments under hydroponic conditions. Results indicated that La(III) treatment increased S. nigrum's aboveground As transport capacity by 58.68 %-213 % compared to no La(III) application. Additionally, foliar spraying of La(III) significantly inhibited the expression of toxic metabolites in the root system of S. nigrum, reducing Benzamide by 99.79 % under SA treatment and ZON by 87.72 % under ROX treatment. La(III) is likely to promote the transport of toxins and nutrients within and out of cells by activating ABC transporters, thereby enhancing S. nigrum's arsenic tolerance and metabolic activity. These findings provide molecular-scale insights into La(III) enhancement of the resilience of hyper-enriched plants and the remediation potential of contaminated sites.
Assuntos
Arseniatos , Lantânio , Roxarsona , Poluentes do Solo , Solanum nigrum , Solanum nigrum/metabolismo , Solanum nigrum/efeitos dos fármacos , Arseniatos/metabolismo , Arseniatos/toxicidade , Roxarsona/metabolismo , Poluentes do Solo/metabolismo , Biodegradação Ambiental , MetabolômicaRESUMO
In recent times, increased geogenic and human-centric activities have caused significant heavy metal(loid) (HM) contamination of soil, adversely impacting environmental, plant, and human health. Phytoremediation is an evolving, cost-effective, environment-friendly, in situ technology that employs indigenous/exotic plant species as natural purifiers to remove toxic HM(s) from deteriorated ambient soil. Interestingly, the plant's rhizomicrobiome is pivotal in promoting overall plant nutrition, health, and phytoremediation. Certain secondary metabolites produced by plant growth-promoting rhizobacteria (PGPR) directly participate in HM bioremediation through chelation/mobilization/sequestration/bioadsorption/bioaccumulation, thus altering metal(loid) bioavailability for their uptake, accumulation, and translocation by plants. Moreover, the metallotolerance of the PGPR and the host plant is another critical factor for the successful phytoremediation of metal(loid)-polluted soil. Among the phytotechniques available for HM remediation, phytoextraction/phytoaccumulation (HM mobilization, uptake, and accumulation within the different plant tissues) and phytosequestration/phytostabilization (HM immobilization within the soil) have gained momentum in recent years. Natural metal(loid)-hyperaccumulating plants have the potential to assimilate increased levels of metal(loid)s, and several such species have already been identified as potential candidates for HM phytoremediation. Furthermore, the development of transgenic rhizobacterial and/or plant strains with enhanced environmental adaptability and metal(loid) uptake ability using genetic engineering might open new avenues in PGPR-assisted phytoremediation technologies. With the use of the Geographic Information System (GIS) for identifying metal(loid)-impacted lands and an appropriate combination of normal/transgenic (hyper)accumulator plant(s) and rhizobacterial inoculant(s), it is possible to develop efficient integrated phytobial remediation strategies in boosting the clean-up process over vast regions of HM-contaminated sites and eventually restore ecosystem health.
Assuntos
Biodegradação Ambiental , Metais Pesados , Poluentes do Solo , Metais Pesados/metabolismo , Poluentes do Solo/metabolismo , Desenvolvimento Vegetal , Plantas/metabolismo , Microbiologia do SoloRESUMO
Iron (Fe) plaque, which forms on the surface of rice roots, plays a crucial role in immobilizing heavy metal(loids), thus reducing their accumulation in rice plants. However, the principal factors influencing Fe plaque formation and its adsorption capacity for heavy metal(loid)s throughout the rice plant's lifecycle remain poorly understood. Thus, this study investigated the dynamics of Fe plaque formation and its ability to adsorb cadmium (Cd) and arsenic (As) across different growth stages, aiming to identify the key drivers behind these processes. The findings reveal that the rate of radial oxygen loss (ROL) and the abundance of plaque-associated microbes are the primary drivers of Fe plaque formation, with their relative importance ranging from 1.4% to 81%. Similarly, the adsorption of As by Fe plaque is principally determined by the rate of ROL and the quantity of Fe plaque, with subsequent effects from the total Fe in rhizospheric soil, arsenate-reducing bacteria, and organic matter-degrading bacteria. The relative importance of these factors ranges from 6.0% to 11.7%. By contrast, the adsorption of Cd onto Fe plaque is primarily affected by competition for adsorption sites with ammonium in soils and the presence of organic matter-degrading bacteria, contributing 25.5% and 23.5% to the adsorption process, respectively. These findings provide significant insights into the development of Fe plaque and its absorption of heavy metal(loid)s throughout the lifecycle of rice plants.