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1.
J Environ Manage ; 289: 112517, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33836437

RESUMEN

Ureolytic bacteria can be a promising mediator used for the immobilization of potentially toxic elements via microbially-induced carbonate precipitation (MICP) process from biodegradable ions to carbonate form. Electronic waste (E-waste) environment is very complex compared to general metal contaminated soil, however, MICP has not been studied under such an environment. In this study, three bacterial strains were successfully isolated from an E-waste area in Guiyu, China, and indicated to have positive ureolytic behavior with significant heavy metal resistance (specific to Cu and Pb), among which, a strain of Lysinibacillus sp. was proven to show a great persistence in heavy metal immobilization. This featured strain can tolerate up to 100 ppm copper and 1000 ppm lead according to minimal inhibitory concentration (MIC) results, and its urease activity was well-adapted to metal effects. Results also revealed the positive correlation (R2 = 0.9819) between metal concentrations and surface layer protein content present in bacterial cells. The underlying mechanism on the role of S-layer protein in heavy metal immobilization during biocalcification was elucidated. The metabolic system of heavy metal resistance for these E-waste derived isolates is novel and represents a point of interest for possible environmental applications to immobilize toxic heavy metals from electronic waste sites.


Asunto(s)
Residuos Electrónicos , Metales Pesados , Contaminantes del Suelo , Bacterias/genética , China , Suelo , Contaminantes del Suelo/toxicidad
2.
Bull Environ Contam Toxicol ; 106(3): 528-535, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33661312

RESUMEN

Phytoremediation is a green, simple, eco-friendly, sustainable, and cost-effective remediation technology to remove and degrade contaminants from soil. In this study, a germination experiment and a pot experiment were performed in greenhouse to evaluate cadmium toxicity and phytoremediation capacity. The results showed that there was the highest membership function value of cadmium (MFVC) in KFJT-3 than that of KFJT-CK and KFJT-1, the value being 0.473, 0.456 and 0.413, respectively. Furthermore, the highest biomass was discovered in KFJT-3 compared to the other genotypes under 50 mg/kg cadmium stress. Physiological analysis showed that proline content significantly increased in KFJT-3, the value being 31.88%. In addition, Bioaccumulation factor (BAF) and Translocation factor (TF) value were 3.80 and 1.02 for KFJT-3, respectively. In conclusion, BAF and TF values showed that the cadmium tolerance of KFJT-1 and KFJT-3 could be higher than that of KFJT-CK, which could be the genotype for phytoremediation of cadmium contaminated soil.


Asunto(s)
Contaminantes del Suelo , Sorghum , Biodegradación Ambiental , Cadmio/análisis , Cadmio/toxicidad , Raíces de Plantas/química , Prolina , Plantones/química , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
3.
Ying Yong Sheng Tai Xue Bao ; 32(3): 1096-1104, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33754577

RESUMEN

Silicon (Si) application could significantly alleviate the toxic effects of cadmium (Cd) on the growth and development of rice. Here, we examined the regulatory effects of Si on Cd accumulation and stress response in rice seedlings through a hydroponic root separation test. The results showed that the biomass of rice seedlings decreased significantly under Cd stress, while the addition of Si could alleviate such negative effect. The uptake, transfer, and accumulation of Cd in rice seedling were significantly affected by Si addition under Cd stress. Si application under the unilateral Cd stress (Si-Cd+Si, Si-Cd) increased Cd-retention coefficient of root by 83.3%-83.6%, which restricted the transfer of Cd from root to aboveground. However, the treatment with Si added to the non-stressed side (Si-Cd) elevated the uptake and accumulation of Cd in rice seedling, with the accumulation in root being increased by 48.2% when compared to the treatment under the unilateral Cd stress without the addition of Si (CK-Cd). The treatment with Si added in two sides (Si-Cd+Si) decreased the uptake of Cd both in root and aboveground parts by 36.7% and 54.9%, respectively. The addition of Si under bilateral Cd stress (Cd-Cd+Si) significantly reduced the Cd uptake of both the root and aboveground parts by 57.8% and 46.5%, respectively, compared to the treatment of bilateral Cd stress (Cd-Cd). Higher Si concentration in rice seedling was found under the Cd stress. More Si was accumulated in rice seedling to resist the Cd stress when Si was added. The addition of Si affected the absorption of other metal elements in rice seedlings, including calcium (Ca), magnesium (Mg) and manganese (Mn). The concentrations of Ca and Mg in root and aboveground parts were significantly increased by Si addition under bilateral Cd-stress (Cd-Cd+Si), but Mn concentration was changed with the stress degree of Cd. The activities of superoxide dismutase (SOD) and peroxidase (POD) in root were affected by Si under Cd stress, especially for the Si-Cd treatment. The activity of POD in the root of the Cd-stress side and that of SOD in non-stress side were significantly increased, which benefit to scavenging the free radicals induced by Cd stress. In conclusion, Si could regulate the growth of rice seedlings, the uptake of elements such as Cd and Si, and the antioxidant reaction of the root system under the Cd stress. High Si concentration in plant is conducive to enhancing Cd tolerance.


Asunto(s)
Oryza , Contaminantes del Suelo , Cadmio/toxicidad , Estrés Oxidativo , Raíces de Plantas , Plantones , Silicio/farmacología , Contaminantes del Suelo/toxicidad
4.
Sensors (Basel) ; 21(5)2021 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-33668135

RESUMEN

This study aimed to determine the impact of tetrabutylphosphonium bromide [TBP][Br] on the soil environment through an experiment on loamy sand samples. The tested salt was added to soil samples at doses of 0 (control), 1, 10, 100, and 1000 mg kg-1 dry matter (DM). During the experiment, the activity of selected enzymes involved in carbon, phosphorus, and nitrogen cycles, characteristics of organic matter with Fourier-transform infrared (FT-IR) spectroscopy, and toxicity of soil samples in relation to Aliivibrio fischeri were determined at weekly intervals. The results showed that low doses of [TBP][Br] (1 and 10 mg kg-1 DM) did not have much influence on the analyzed parameters. However, the addition of higher doses of the salt into the soil samples (100 and 1000 mg kg-1 DM) resulted in a decrease in the activity of enzymes participating in the carbon and phosphorus cycle and affected the activation of those enzymes involved in the nitrogen cycle. This may be due to changes in aerobic conditions and in the qualitative and quantitative composition of soil microorganisms. It was also observed that the hydrophobicity of soil organic matter was increased. Moreover, the findings suggested that the soil samples containing the highest dose of [TBP][Br] (1000 mg kg-1 DM) can be characterized as acute environmental hazard based on their toxicity to Aliivibrio fischeri bacteria. The increased hydrophobicity and ecotoxicity of the soil samples exposed to the tested salt were also positively correlated with the activity of dehydrogenases, proteases, and nitrate reductase. Observed changes may indicate a disturbance of the soil ecochemical state caused by the presence of [TBP][Br].


Asunto(s)
Aliivibrio fischeri/efectos de los fármacos , Aliivibrio fischeri/enzimología , Compuestos Organofosforados/toxicidad , Contaminantes del Suelo/toxicidad , Suelo , Espectroscopía Infrarroja por Transformada de Fourier
5.
Environ Int ; 151: 106451, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33647835

RESUMEN

Polyfluoroalkyl phosphate esters (PAPs) are high production volume surfactants used in the food contact paper and packaging industries. They are prone to partition to soil due to their strong hydrophobicity and may biotransform into recalcitrant perfluoroalkyl carboxylic acids (PFCAs); little is known about their fate and behaviors in terrestrial organisms. Here, geophagous earthworms (M. guillelmi) were exposed to 6:2 fluorotelomer phosphate diester (6:2 diPAP)-contaminated soil to examine tissue-specific accumulation and biotransformation. 6:2 diPAP quickly accumulated in M. guillelmi with the highest biota-soil-accumulation factor (BSAF) in the gut, followed by the organs, skin, and body fluid. The total amount of 6:2 diPAP accumulated in the skin was the highest due to its high mass content. These results indicated that skin absorption and gut processes were two major pathways for earthworms to accumulate 6:2 diPAP from soil. In vitro desorption experiments indicated that the gut digestion fluid greatly promoted the desorption of 6:2 diPAP from the soil and enhanced its bioavailability. Degradation of 6:2 diPAP in the soil was stimulated when the earthworm appeared. In contrast to the soil, a more extensive transformation occurred in the earthworm. Perfluorohexanoic acid (PFHxA) was the primary phase Ⅰ product, followed by perfluoropentyl propanoic acid (FPePA), perfluoropentanoic acid (PFPeA), 2-perfluorohexyl ethanoic acid (FHEA), and perfluoroheptanoic acid (PFHpA), which confirmed the occurrence of α- and ß-oxidation in earthworms. For the first time, a new phase II product, namely, a 6:2 fluorotelomer alcohol sulfate conjugate, was identified in earthworms at unexpectedly high levels, which might be the primary way earthworms eliminate 6:2 diPAP. Both in vivo and in vitro experiments suggested that 6:2 diPAP experienced faster and more extensive biotransformation in the gut than in the organs. This work sheds light on the bioaccumulation and biotransformation of 6:2 diPAP in terrestrial invertebrates, providing strong evidence of indirect sources of PFCAs in the environment.


Asunto(s)
Oligoquetos , Contaminantes del Suelo , Animales , Biotransformación , Organofosfatos/toxicidad , Fosfatos/análisis , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
6.
Environ Pollut ; 278: 116837, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33706243

RESUMEN

Sedum alfredii is a Cd/Zn hyperaccumulator native to China, which was collected from a mined area where Mn content in soil was extremely high, together with Zn and Cd content. We investigated the tolerance and accumulation ability of Mn and its possible association with Cd hyperaccumulation in this plant species by using MP-AES, SR-µ-XRF, and RT-PCR. The results showed that the hyperaccumulating ecotype (HE) S. alfredii exhibited high tolerance to Mn and accumulating around 10,000 and 12,000 mg kg-1 Mn in roots and shoots, respectively, without exhibiting toxicity under 5000 mg kg-1 Mn treatment for 4 weeks. Exposure to Cd significantly reduced plant uptake of Mn. In contrast, exogenous Mn application significantly improved root uptake and root-to-shoot translocation of Cd, resulting in the increased Cd accumulation in the shoots of HE S. alfredii. SR-µ-XRF analysis demonstrated that high Mn (20 µM) exposure resulted in higher intensities of Cd localized in both stem vascular bundles and cortex, as well as leaf mesophyll cells, than in those treated with low Mn levels (0.2 µM or 2.0 µM). RT-PCR analysis of several genes possibly involved in Mn/Cd transportation showed that expression of SaNramp3 in roots was significantly reduced under high Mn exposure. These results suggested a significant interaction between Cd and Mn in the HE S. alfredii plants, possibly through their competition for transporters and theoretically provided a strategy to improve the efficiency of Cd extraction from polluted soils by this plant species, after using appropriate nutrient management of Mn.


Asunto(s)
Sedum , Contaminantes del Suelo , Cadmio , China , Raíces de Plantas/química , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad , Zinc
7.
Ecotoxicol Environ Saf ; 215: 112139, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33761378

RESUMEN

Cadmium (Cd) accumulation in arable lands has become a serious matter for food security. Among various approaches, the application of nanoparticles (NPs) for remediation of contaminated water and soils is attaining more popularity worldwide. The current field experiment was executed to explore the impacts of single and combined use of ZnO NPs, Fe NPs and Si NPs on wheat growth and Cd intake by plants in a Cd-contaminated field. Wheat was sown in a field which was contaminated with Cd and was irrigated with the raw-city-effluent while NPs were applied as foliar spray alone and in all possible combinations. The data revealed that straw and grain yields were enhanced in the presence of NPs over control. Chlorophyll, carotenoids contents and antioxidants activities were enhanced while electrolyte leakage was reduced with all NPs over control. In comparison with control, Cd uptake in wheat straw was reduced by 84% and Cd uptake in grain was reduced by 99% in T8 where all three NPs were foliar-applied simultaneously. Zinc (Zn) and iron (Fe) contents were increased in those plants where ZnO and Fe NPs were exogenously applied which revealed that ZnO and Fe NPs enhanced the bio-fortification of Zn and Fe in wheat grains. Overall, foliar application of different NPs is beneficial for better wheat growth, yield, nutrients uptake and to lessen the Cd intake by plants grown in Cd-contaminated soil under real field conditions.


Asunto(s)
Cadmio/metabolismo , Nanopartículas/química , Contaminantes del Suelo/metabolismo , Triticum/fisiología , Antioxidantes , Cadmio/análisis , Cadmio/toxicidad , Clorofila , Grano Comestible/química , Contaminación Ambiental , Hojas de la Planta/química , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad , Triticum/crecimiento & desarrollo , Zinc/análisis , Óxido de Zinc
8.
Environ Pollut ; 277: 116758, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33652182

RESUMEN

Rhizobia and arbuscular mycorrhiza fungi (AMF) are important symbiotic microbes that are advantageous to plants growing in metal-contaminated soil. However, it remains unclear how inoculated microbes affect rhizosphere microbial communities or whether subsequent changes in rhizosphere microbiomes contribute to improving plant resistance under metal stress. This study investigated the effects of rhizobia and AMF inoculation on alfalfa resistance to Cd stress. The response of rhizosphere microbial communities to inoculation and its role in increasing alfalfa' ability to cope with stress were further analyzed using high-throughput sequencing of 16S and ITS rRNA genes. Results showed that single rhizobia or AMF inoculation significantly improved alfalfa resistance to Cd stress, while their co-inoculation resulted in the greatest overall improvement. Improved resistance was reflected by the significant mitigation of Cd-induced lipid peroxidation and reactive oxygen species (ROS) stress caused by increases in antioxidant enzyme activities along with co-inoculation. Furthermore, co-inoculation significantly altered the rhizosphere microbial community structure by decreasing fungal community diversity and increasing bacterial community diversity. Results of partial least squares path modeling (PLS-PM) and variation partitioning analysis (VPA) showed that the rhizosphere bacterial community predominated over the fungal community with respected to improvements in resistance to Cd stress under the co-inoculation treatments. This improvement was specifically seen in the enrichment of certain key bacterial taxa (including Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi) induced by the rhizobia and AMF co-inoculation, enhancing alfalfa' ability to uptake rhizosphere nutrients and reduce its release of photosynthetically-derived carbon (C) into soil. Our findings revealed that the co-inoculation of multiple symbiotic microbes can assist plants to effectively cope with Cd stress, providing a greater understanding of rhizosphere bacterial taxa in the microbe-induced phytomanagement.


Asunto(s)
Micorrizas , Rhizobium , Contaminantes del Suelo , Cadmio/toxicidad , Hongos , Medicago sativa , Micorrizas/química , Raíces de Plantas/química , Rizosfera , Suelo , Microbiología del Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
9.
Environ Pollut ; 279: 116891, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33751947

RESUMEN

In this paper, cadmium (Cd) stress tests were performed on Eisenia fetida in sterile artificial soil, and its regulatory mechanism between microbial communities in vivo and in vitro after Cd stress was explored. In the test, 0, 50, 100, 125, 250 and 500 mg kg-1 Cd stress concentrations were implemented. After long-term and short-term stress, the microbes in the earthworms and the soil were cultured with ECO plates. The data statistics of carbon source utilization intensity were carried out using the method developed by our team. CCA was scientifically integrated into TOPSIS to establish a new data analysis model to find the regulatory nodes after stress (Ning et al., 2020). Macro gene sequencing technology revealed that the species with the highest absolute abundance in the microbial communities in vivo and in vitro were all unnamed new species. It was confirmed that the HBA gene, NEUROD1 gene and ABCA3 gene were the regulatory genes of the microbial community in the earthworms under Cd stress, while the TC.FEV.OM gene and cheBR gene were the main regulatory genes of the microbial community in the soil. These results provide a scientific and theoretical reference and model basis for the bioremediation of Cd-contaminated soil and the detoxification mechanism of earthworms.


Asunto(s)
Microbiota , Oligoquetos , Contaminantes del Suelo , Animales , Cadmio/análisis , Cadmio/toxicidad , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
10.
Chemosphere ; 271: 129808, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33736226

RESUMEN

Pb, Ni, and Co are among the most toxic heavy metals that pose direct risks to humans and biota. There are no published studies on biochars produced at low temperatures (i.e., 300 °C), which possess high sorption capacity for heavy metal remediation and reclamation of contaminated sandy soils. This research studied the effect of catalytic microwave pyrolysis of switchgrass (SG) using bentonite and K3PO4 to produce biochar at low temperature (300 °C) with high sorption capacity for reducing the phytotoxicity of heavy metals, and investigated the synergistic effects of catalyst mixture on biochar sorption capacity. The quality of the biochars was examined in terms of their impacts on plant growth, reducing phytotoxicity and uptake of heavy metals in sandy soil spiked with Pb, Ni, and Co. All catalysts increased the micropore surface area and cation-exchange capacity of biochars, and resulted in biochars rich in plant nutrients, which not only decreased heavy metal phytotoxicity, but also boosted plant growth in the spiked soil by up to 140% compared to the sample without biochar. By mixing bentonite and K3PO4 with SG during microwave pyrolysis, the efficacy of biochar in reducing phytotoxicity and heavy metals uptake was further enhanced because of the highest micropore surface area (402 m2/g), moderate contents of Ca, Mg, K, and Fe for ion-exchange and moderate concentration of phosphorus for the formation of insoluble heavy metal compounds. Generally, the biochar created at 300 °C (300-30KP) showed similar performance to the biochar created at 400 °C (400-30KP) in terms of reducing heavy metal bioavailability.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Carbón Orgánico , Humanos , Metales Pesados/análisis , Metales Pesados/toxicidad , Microondas , Pirólisis , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
11.
Sci Total Environ ; 769: 145246, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33736251

RESUMEN

Potentially Toxic Elements (PTEs) otherwise known as heavy metals are ubiquitous in soils and can have a range of negative health and environmental impacts. In terrestrial systems understanding how PTEs move in the environment is made challenging by the complex interactions within soil and the wider environment and the compositional nature of PTEs. PTEs are compositional because data of individual PTEs within in a sample are ratios which may be under a sum constraint, where individual components sum up to a whole. In this study three different scenarios were considered, one using the centred log ratio transformation (clr) a compositional transformation, the more "traditional" log10 transformation (log10) and untransformed data acting as a comparison (unt) were applied to four different datasets. Three were the Liver, Muscle and Kidney tissue of Eurasian Badgers (Meles meles) and the fourth was soil and data were extracted from a regional geospatial survey. Cluster analysis demonstrated that the clr and log10 transformation were able to resolve compositional trends at the point of the individual sample, whilst unt could not and did not meet the preconditions for the next phase of analysis. At the level of compositional trends between PTEs complex heatmaps demonstrated that clr was able to isolate PTE relationships and highlight commonalities between different datasets, whilst log10 could not. In the final phase, principal component analysis (PCA) of the clr transformation showed similarities between the signals in the soft tissues and the disparities they had with soil, whilst the log10 transformation was unable to achieve this. Overall, the clr transformation was shown to perform more consistently under a variety of analytical scenarios and the compositional approach will provide more realistic interpretations about PTEs in both soil and animal soft tissue than the log10 or unt conditions.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Animales , Ecotoxicología , Monitoreo del Ambiente , Metales Pesados/análisis , Metales Pesados/toxicidad , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
12.
Sci Total Environ ; 769: 145221, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33736258

RESUMEN

Cadmium and salinity are the major threats to environmental resources and agricultural practice worldwide. The present work aims green synthesis, characterization, and application of iron oxide nanoparticles for co-alleviation of Cd and salt stresses in wheat plants. The iron oxide NPs were synthesized from a native bacterial strain, Pantoea ananatis strain RNT4, yielding a spherical FeO-NPs with a size ranging from 19 to 40 nm evidenced by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. Results showed that application of 100 mg kg-1 of the bioengineered FeO-NPs in an original saline soil stimulated wheat plant growth, gaining 36.7% of additional length as compared with the control scenarios, via alleviating the detrimental effects of abiotic stresses and thereby reprogramming the morpho-physiological state of wheat plants. In addition, the presence of FeO-NPs in soil significantly increased the nutrient concentrations of N, P and K+, while reducing the Na+ and Cl- components in the wheat grain. Interestingly, application of the FeO-NPs in Cd-polluted soils eventually reduced wheat plant uptake of Cd by 72.5%, probably due to the adsorption of Cd onto the large surface of NPs and thereby, constraining Cd bioavailability to the plants. It provides the first evidence that a FeO-NPs-based treatment could be a candidate agricultural strategy for mitigating the Cd and salt stresses in Cd-polluted saline soils for safe agriculture practice.


Asunto(s)
Cadmio , Contaminantes del Suelo , Cadmio/análisis , Cadmio/toxicidad , Pantoea , Salinidad , Estrés Salino , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad , Triticum
13.
Sci Total Environ ; 769: 144648, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33736260

RESUMEN

Arsenic (As)-reducing bacteria are able to influence As-speciation and, in this way, change As bio-availability. In consequence, this has an impact on As uptake by plants growing on polluted soil and on the effectiveness of the phytoremediation process. To be able to efficiently utilize these bacteria for As-phytoremediation in the field, a better understanding of the plant-bacterial interactions involved in As-tolerance or toxicity is needed. In this work, seedlings of a clone of Salix atrocinerea derived from a specimen naturally growing on an As-polluted brownfield were grown under gnotobiotic conditions exposed to As, and in the presence or absence of two of its field-associated and in vitro characterized plant growth-promoting (PGP) bacteria. The inoculation with Pantoea sp., induced a moderate reduction of AsV to AsIII in the exposure medium that, together with a coordinated plant response of As uptake, chelation and sequestration, increased As accumulation in roots; which is reflected into a higher phytostabilization. However, inoculation with Rhodococcus erythropolis due to a higher disproportionate reduction of AsV to AsIII in the medium caused less As accumulation in roots that non-bioaugmented plants and despite the lower As content, the concentrations of AsIII present in the medium and the damage suffered in roots and leaves, indicated that As tolerance mechanisms (such as prevention of AsIII uptake and efflux) did not occur in time to avoid physical disturbance and plants growth reduction. Interestingly, by two different metabolic pathways -coordinated by different key transporters mediating As uptake, tolerance, distribution and vacuolar accumulation at the roots- both bacteria limited As accumulation in Salix shoots. Our results provide for the first time a detailed insight in the plant-bacterial responses and physiological changes contributing to As tolerance in S. atrocinerea, that will facilitate the design of effective strategies for exploitation of plant-associated microorganisms for phytoremediation.


Asunto(s)
Arsénico , Rhodococcus , Salix , Contaminantes del Suelo , Arseniatos , Biodegradación Ambiental , Raíces de Plantas/química , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
14.
Huan Jing Ke Xue ; 42(2): 952-959, 2021 Feb 08.
Artículo en Chino | MEDLINE | ID: mdl-33742891

RESUMEN

Peppers are a high Cd-enriched vegetable. On the basis of a preliminary screening experiment of 91 pepper varieties and soil culture experiments during the entire growth period of 26 varieties, a high Cd variety (X15), medium Cd variety (X39), and two low varieties (X45 and X55) were selected to study the effect of different cadmium levels (0, 5, and 10 mg·kg-1 Cd) on enrichment, transport, and accumulation as well as its subcellular distribution and chemical form. Based on the results, 5 mg·kg-1 and 10 mg·kg-1 of Cd inhibited shoot dry weights of four pepper varieties but increased the root dry weights of X15, X45, and X55 varieties. Sodium chloride-bound cadmium and acetate-bound cadmium are the main forms of cadmium in the pepper fruits. Subcellular cadmium concentrations in the roots, leaves, and fruits of pepper plants were ranked in order cytoplasm > cell wall > organelle, and in the stems the order was cell wall > cytoplasm > organelle. Cd compartmentalization plays an important role in pepper resistance to cadmium stress. Under dosages of 5 mg·kg-1 Cd and 10 mg·kg-1 Cd, Cd concentrations in stems and leaves were ranked in order X39 > X15 > X55 > X45, with fruit Cd concentrations ranked in order X15 > X39 > X55 > X45. The Cd concentration was lowest in the roots of X15 whereas this variety has the highest concentrations in its fruit. The Cd concentrations in the roots, stems, and leaves of X39 were the highest among the four varieties whereas the concentration in the fruit was lower than in the X15 variety. The concentration of Cd in pepper fruits depends on the Cd transport capacity redistribution ability to the shoots.


Asunto(s)
Cadmio , Contaminantes del Suelo , Cadmio/análisis , Cadmio/toxicidad , Frutas/química , Hojas de la Planta/química , Raíces de Plantas/química , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad , Verduras
15.
Huan Jing Ke Xue ; 42(3): 1177-1184, 2021 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-33742914

RESUMEN

A pot experiment was conducted to investigate the growth response and Cd accumulation characteristics among different populations of Hylotelephium spectabile in Cd-contaminated cinnamon soil (2.22 mg·kg-1) with the addition of different concentrations of NaCl. Results showed that the biomasses and Cd concentrations of H. spectabile showed significant differences among different populations under Cd alone or Cd-salt combined stress. Moreover, salt stress aggravated the growth inhibition of H. spectabile and the Cd concentrations in different H. spectabile populations showed a declining trend, which may be related to the salt-derived pH increase leading to a decrease in Cd bioavailability. In addition, the growth and Cd absorption responses of H. spectabile under salt stress were significantly different in the different populations. The shoot biomasses of the LN population were significantly higher than in other populations under different treatment, and showed no significant decrease with the addition of 1% NaCl when compared with the control treatment and the tolerance index remained 0.91. At the same time, the shoot Cd concentration of the LN population was significantly higher than in other populations under different treatments. The result may be attributed to the Cd accumulation and detoxification mechanisms in LN are prior than other populations that may also have important physiological mechanisms for tolerance of salt stress. In summary, although Cd uptake in H. spectabile decreased with salt stress, there were significant differences among different populations. LN populations accumulated 84.4 µg·plant-1 Cd in shoots with 2% NaCl addition, which was 48.4%-89.3% higher than in other populations. Therefore, H. spectabile, especially LN populations, is a good candidate for phytoremediation of Cd-contaminated saline soil.


Asunto(s)
Cadmio , Contaminantes del Suelo , Biodegradación Ambiental , Cadmio/toxicidad , Raíces de Plantas , Estrés Salino , Contaminantes del Suelo/toxicidad
16.
Huan Jing Ke Xue ; 42(3): 1197-1204, 2021 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-33742917

RESUMEN

With the rapid development of industry, chromium (Cr) has become one of the main soil heavy metal pollutants in China, seriously affecting the soil ecological environment and health of residents. In this study, contaminated soil samples were taken around the tannery sludge yard area in Heibei Province. The Illumina MiSeq high-throughput sequencing technology was employed to analyze the structure and assembly processes of soil bacterial communities at different pollution levels. Results showed that chromium pollution significantly influences soil properties and soil bacterial communities. The composition and structure of bacterial communities were significantly shifted at different pollution levels. Furthermore, the α diversity of bacterial communities may decrease with relatively high concentrations of chromium. Bacterial communities in chromium polluted soil can be divided into 55 phyla, where Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, and Firmicutes are the dominant phyla (relative abundance>5%). Moreover, the soil bacterial communities were dominated by the deterministic assembly process (homogeneous selection) and the stochastic ratios decreased with increases in the concentration of chromium in soil. The total concentration of chromium, soil moisture, pH, and organic matter were significantly correlated (P<0.05) with the bacterial communities. Therefore, these soil properties might be the driving factors affecting the structure of bacterial communities.


Asunto(s)
Contaminantes del Suelo , Suelo , China , Cromo/análisis , Cromo/toxicidad , Microbiología del Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
17.
Huan Jing Ke Xue ; 42(3): 1545-1558, 2021 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-33742952

RESUMEN

Residual tetracycline antibiotics (TCs) in farmland soils with the application of livestock manure cause risks to the growth of vegetables and soil ecology. Here, pot experiments are carried out using through exogenous addition of different levels of oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC), to study the physiological toxicity, uptake, and transportation of TCs in lettuce. The subsequent degradation of TCs in soil was also evaluated along with analyses of soil enzyme activity and microbial population dynamics. The results showed that the biomass of lettuce decreased with application of TCs as well as the chlorophyll-a, chlorophyll-b, and carotenoid content. Consequently, net photosynthetic rates were inhibited, and SOD, POD, and CAT increased under the stress imposed by the TCs. With an increase in the level of TC application, uptake by lettuce plants increased while the bioconcentration and translocation factors decreased. When OTC, TC, and CTC in the soil were below 150 mg·kg-1, the health risk from the edible parts of lettuce was low (HQ<0.1). The TC degradation rate in different soils was ranked in the order of control soil > rhizosphere soil > bulk soil. The OTC degradation rates in the soils were significantly lower than for TC and CTC. TCs (150-1350 mg·kg-1) significantly inhibited urease and rhizosphere catalase activity in soil and reduced the number of soil culturable bacteria and fungi.


Asunto(s)
Clortetraciclina , Oxitetraciclina , Contaminantes del Suelo , Animales , Antibacterianos , Lechuga , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad , Tetraciclina
18.
Ecotoxicol Environ Saf ; 214: 112097, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33667736

RESUMEN

Plant ZIP genes represent an important transporter family and may be involved in cadmium (Cd) accumulation and Cd resistance. In order to explore the function of SmZIP isolated from Salix matsudana, the roles of SmZIP in Cd tolerance, uptake, translocation, and distribution were determined in the present investigation. The transgenic SmZIP tobacco was found to respond to external Cd stress differently from WT tobacco by exhibiting a higher growth rate and more vigorous phenotype. The overexpression of SmZIP in tobacco resulted in the reduction of Cd stress-induced phytotoxic effects. Compared to WT tobacco, the Cd content of the root, stem, and leaf in the transgenic tobacco increased, and the zinc, iron, copper, and manganese contents also increased. The assimilation factor, translocation factor and bioconcentration factor of Cd were improved. The scanning electron microscopy and energy dispersive X-ray analysis results of the root maturation zone exposed to Cd for 24 h showed that Cd was transferred through the root epidermis, cortex, and vascular cylinder and migrated to the aboveground parts via the vascular cylinder, resulting in the transgenic tobacco accumulating more Cd than the WT plants. Based on the transverse section of the leaf main vein and leaf blade, Cd was transported through the vascular tissues to the leaves and accumulated more greatly in the leaf epidermis, but less in the leaf mesophyll cells, following the overexpression of SmZIP to reduce the photosynthetic toxicity. The overexpression of SmZIP resulted in the redistribution of Cd at the subcellular level, a decrease in the percentage of Cd in the cell wall, and an increase of the Cd in the soluble fraction in both the roots and leaves. It also changed the percentage composition of different Cd chemical forms by elevating the proportion of Cd extracted using 2% HAc and 0.6 mol/L HCl, but lowering that of the Cd extracted using 1 mol/L NaCl in both the leaves and roots under 10 and 100 µmol/L Cd stress for 28 d. The results implied that SmZIP played important roles in advancing Cd uptake, accumulation, and translocation, as well as in enhancing Cd resistance by altering the Cd subcellular distribution and chemical forms in the transgenic tobacco. The study will be useful for future phytoremediation applications to clean up Cd-contaminated soil.


Asunto(s)
Cadmio/toxicidad , Contaminantes del Suelo/toxicidad , Tabaco/fisiología , Biodegradación Ambiental , Cadmio/análisis , Pared Celular/química , Genes de Plantas , Hojas de la Planta/efectos de los fármacos , Raíces de Plantas/efectos de los fármacos , Salix , Contaminantes del Suelo/análisis , Tabaco/efectos de los fármacos , Zinc/análisis
19.
Bull Environ Contam Toxicol ; 106(3): 507-515, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33559032

RESUMEN

Heavy metal contamination of soil is of increasing concern because of its potential risk to human health. In this study, two AMFs (Rhizophagus intraradices and Funneliformis mosseae) substantially increased the biomass of bashfulgrass in Zn-contaminated soil, even at Zn levels of up to 600 mg kg-1. Zn uptake in R. intraradices- and F. mosseae-mycorrhizal bashfulgrass was increased by 40-fold and 7-fold, respectively, when plants grown in Zn-contaminated (400 mg kg-1) soil. Elemental analysis showed that neither AMF had an effect on Zn concentration in plant tissues, including the roots and shoots. However, a significant increase of phosphorus (P) concentration was observed, suggesting the increased is from the improved use efficiency of soil nutrients by AMFs. Comparing the two AMFs, better growth performance with more biomass occurred with R. intraradices-inoculated bashfulgrass in Zn-contaminated soil. This is consistent with R. intraradices being more tolerant to Zn than F. mosseae, indicated by a higher colonization percentage in bashfulgrass roots. Taken together, our data indicate that AMFs possibly improve acquisition and translocation of P to promote increased biomass. Moreover, mycorrhiza did not enhance Zn accumulation in shoots and roots of bashfulgrass at the same Zn level. In the future, developing AMF (especially R. intraradices) inoculation of plants might be a desirable means of safe production of ornamental plants in metal-polluted soil.


Asunto(s)
Mimosa , Micorrizas , Contaminantes del Suelo , Hongos , Humanos , Fósforo , Raíces de Plantas , Suelo , Contaminantes del Suelo/toxicidad , Zinc/toxicidad
20.
Ecotoxicol Environ Saf ; 213: 112023, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33578096

RESUMEN

Arbuscular mycorrhizal fungi (AMF) play an important role in improving plant tolerance and accumulation of zinc (Zn) and cadmium (Cd). The growth, physiology and absorption of elements and transport in Phragmites australis (P. australis) were investigated under Zn and Cd stress to identify the transport mechanisms of toxic trace elements (TE) under the influence of AMF. Thus, AMF were observed to alleviate the toxic effects of Zn and Cd on P. australis by increasing plant biomass and through different regulatory patterns under different TE concentrations. The activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) increased under Zn stress, and the activities of SOD, catalase (CAT), peroxidase (POD), and APX significantly increased under high concentrations of Cd. AMF differ in their strategies of regulating the transport of different metals under TE stress. Under Zn stress, the concentration of Zn in P. australis decreased by 10-57%, and the effect on Zn translocation factor (TFZn) was concentration-dependent. AMF increased the TFZn under low concentration stress, but decreased under high concentration stress. Under Cd stress, the concentration of Cd increased by as much as 17-40%, and the TFCd decreased. AMF were also found to change the interaction of Zn×Cd. In the absence of AMF, Cd exposure decreased the Zn concentrations in P. australis at Zn100 mg/L and Zn300 mg/L, while it increased the contents of Zn at Zn700 mg/L. The opposite trend was observed following treatment with AMF. However, regardless of the concentration of Cd, the addition of Zn decreased the concentration of Cd in both treatments in both the presence and absence of AMF. Under different TE stress conditions, the regulation of metal elements by AMF in host plants does not follow a single strategy but a trade-off between different trends of transportations. The findings of our study are important for applying AMF-P. australis systems in the phytoremediation of Zn-Cd co-contaminated ecosystems.


Asunto(s)
Micorrizas/fisiología , Poaceae/fisiología , Contaminantes del Suelo/toxicidad , Biodegradación Ambiental , Biomasa , Cadmio/metabolismo , Cadmio/toxicidad , Ecosistema , Raíces de Plantas/efectos de los fármacos , Plantas/efectos de los fármacos , Poaceae/efectos de los fármacos , Poaceae/microbiología , Contaminantes del Suelo/análisis , Contaminantes del Suelo/metabolismo , Oligoelementos/metabolismo , Oligoelementos/toxicidad , Zinc/farmacología
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