RESUMO
Recent technological developments pave the path for deep learning-based techniques to be used in almost every domain of life. The precision of deep learning techniques make it possible for these to be used in the medical field for the classification and detection of various diseases. Recently, the coronavirus (COVID-19) pandemic has put a lot of pressure on the health system all around the world. The diagnosis of COVID-19 is possible by PCR testing and medical imagining. Since COVID-19 is highly contagious, diagnosis using chest X-ray is considered safe in various situations. In this study, a deep learning-based technique is proposed to classify COVID-19 infection from other non-COVID-19 infections. To classify COVID-19, three different pre-trained models named EfficientNetB1, NasNetMobile and MobileNetV2 are used. The augmented dataset is used for training deep learning models while two different training strategies have been used for classification. In this study, not only are the deep learning model fine-tuned but also the hyperparameters are fine-tuned, which significantly improves the performance of the fine-tuned deep learning models. Moreover, the classification head is regularized to improve the performance. For the evaluation of the proposed techniques, several performance parameters are used to gauge the performance. EfficientNetB1 with regularized classification head outperforms the other models. The proposed technique successfully classifies four classes that include COVID-19, viral pneumonia, lung opacity, and normal, with an accuracy of 96.13%. The proposed technique shows superiority in terms of accuracy when compared with recent techniques present in the literature.
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COVID-19 , Aprendizado Profundo , Algoritmos , Humanos , Redes Neurais de Computação , SARS-CoV-2 , Raios XRESUMO
Low use efficiency of nitrogen (N) and phosphorus (P) is major challenge of modern agriculture. Coating of conventional fertilizers with nanomaterials is a promising technique for improved nutrient use efficiency. In current study, nanoparticles (NPs) of potassium ferrite (KFeO2 NPs) were coated on di-ammonium phosphate (DAP) fertilizer with three rates (2, 5, 10%) of KFeO2 NPs and were evaluated for release of N, P, K and Fe supplementation in clay loam and loam soil up to 60 days. The NPs were characterized for crystal assemblage, bond formation, morphology and configuration using the x-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform-infra red spectroscopy (FT-IR). The results showed that size of NPs ranged between 7 and 18 nm. The controlled release of P in 10% KFeO2 nano-coated DAP was observed throughout the incubation period. The P release kept on increasing from day-1 (14.5 µg g-1) to day-60 (178.6 µg g-1) in coated DAP (10%) in loam soil. The maximum release of 50.4 µg g-1 NH4+1-N in coated DAP (10%) was observed after 30 days of incubation. The release of NO3-1-N was consistent up to 45 and 60 days in clay loam and loam soil, respectively. The average release of potassium and iron in 60 days was 19.7 µg g-1 and 7.3 µg g-1 higher in 10% coated DAP than traditional DAP in clay loam soil. It was concluded that KFeO2 nano-coated DAP supplied P and mineral N for longer period of time in both soils, and some higher coating levels should be tested in future.
Assuntos
Fertilizantes/análise , Nanopartículas/química , Fosfatos/química , Potássio , Agricultura , Argila , Compostos Férricos , Nitrogênio , Nutrientes , Fósforo/química , Solo/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios XRESUMO
Agricultural soils are receiving higher inputs of trace elements (TEs) from anthropogenic activities. Application of nanoparticles (NPs) in agriculture as nano-pesticides and nano-fertilizers has gained rapid momentum worldwide. The NPs-based fertilizers can facilitate controlled-release of nutrients which may be absorbed by plants more efficiently than conventional fertilizers. Due to their large surface area with high sorption capacity, NPs can be used to reduce excess TEs uptake by plants. The present review summarizes the effects of NPs on plant growth, photosynthesis, mineral nutrients uptake and TEs concentrations. It also highlights the possible mechanisms underlying NPs-mediated reduction of TEs toxicity at the soil and plant interphase. Nanoparticles are effective in immobilization of TEs in soil through alteration of their speciation and improving soil physical, chemical, and biological properties. At the plant level, NPs reduce TEs translocation from roots to shoots by promoting structural alterations, modifying gene expression, and improving antioxidant defense systems. However, the mechanisms underlying NPs-mediated TEs uptake and toxicity reduction vary with NPs type, mode of application, time of NPs exposure, and plant conditions (e.g., species, cultivars, and growth rate). The review emphasizes that NPs may provide new perspectives to resolve the problem of TEs toxicity in crop plants which may also reduce the food security risks. However, the potential of NPs in metal-contaminated soils is only just starting to be realized, and additional studies are required to explore the mechanisms of NPs-mediated TEs immobilization in soil and uptake by plants. Such future knowledge gap has been highlighted and discussed.
Assuntos
Nanopartículas , Plantas/efeitos dos fármacos , Oligoelementos/metabolismo , Oligoelementos/toxicidade , Agricultura , Metais/metabolismo , Metais/toxicidade , Raízes de Plantas/metabolismo , Plantas/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidadeRESUMO
Nanotechnology is capturing great interest worldwide due to their stirring applications in various fields. Among nanoparticles (NPs), titanium dioxide (TiO2) NPs have been widely used in daily life and can be synthesized through various physical, chemical, and green methods. Green synthesis is a non-toxic, cost-effective, and eco-friendly route for the synthesis of NPs. Plenty of work has been reported on the green, chemical, physical and biological synthesis of TiO2 NPs and these NPs can be characterized through high tech. instruments. In the present review, dense data have been presented on the comparative synthesis of TiO2 NPs with different characteristics and their wide range of applications. Among the TiO2 NPs synthesis techniques, the green methods have been proven to be efficient than chemical synthesis methods because of the less use of precursors, time-effectiveness, and energy-efficiency during the green synthesis procedures. Moreover, this review describes the types of plants (shrubs, herbs and trees), microorganisms (bacteria, fungi and algae), biological derivatives (proteins, peptides, and starches) employed for the synthesis of TiO2 NPs. The TiO2 NPs can be effectively used for the treatment of polluted water and positively affected the plant physiology especially under abiotic stresses but the response varied with types, size, shapes, doses, duration of exposure, metal species along with other factors. This review also highlights the regulating features and future standpoints for the measurable enrichment in TiO2 NPs product and perspectives of TiO2 NPs reliable application.
Assuntos
Nanopartículas , Titânio , Nanopartículas Metálicas/química , Extratos Vegetais , Plantas/químicaRESUMO
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.
Assuntos
Cádmio/metabolismo , Nanopartículas/química , Poluentes do Solo/metabolismo , Triticum/fisiologia , Antioxidantes , Cádmio/análise , Cádmio/toxicidade , Clorofila , Grão Comestível/química , Poluição Ambiental , Folhas de Planta/química , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Triticum/crescimento & desenvolvimento , Zinco/análise , Óxido de ZincoRESUMO
Amine functionalized carbon (AFC) was synthesized from raw oil fly ash and later utilized it for simultaneous removal of methyl orange (MO) and rhodamine 6G (Rh6G) pollutant dyes from aqueous medium. AFC was analyzed through scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area and Fourier transform infrared spectroscopy (FTIR) to examine its morphology, porosity and structural characteristics, respectively. The effect of various process parameters like mixing time, pollutant concentration, adsorbent dose, initial solution pH, and temperature of the medium were investigated for dye removal process. The experimental findings showed that the percentage removal of Rh6G was higher than MO and both dyes showed synergism during the adsorption from binary dye solution. Pseudo-second-order model was most appropriate model for both dyes and thermodynamic parameters showed that the dyes removal process was endothermic in nature. Among various isotherm models, Hill and Toth isotherms best explain the adsorption of Rh6G and MO from binary dye solution.
Assuntos
Corantes , Poluentes Químicos da Água , Adsorção , Aminas , Carbono , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , ÁguaRESUMO
The present study demonstrated the possible impacts of iron oxide nanoparticles (Fe NPs) on the alleviation of toxic effects of cadmium (Cd) in wheat and enhance its growth, yield, and Fe biofortification. A pot experiment was conducted in historically Cd-contaminated soil using five levels of Fe NPs (0, 5, 10, 15, and 20â¯ppm) by soil and foliar application methods. The plants were harvested after 125 days of growth while vegetative parameters, antioxidant capacity, electrolyte leakage (EL) in leaves as well as Cd, and Fe concentrations in wheat grains, roots, and shoots were measured. The results showed that the application of Fe NPs mitigated the Cd toxicity on wheat growth and yield parameters. The exogenous application of Fe NPs enhanced the wheat morphological parameters, photosynthetic pigments, and dry biomass of shoots, roots, spike husks and grains. The activities of super oxide dismutase and peroxidase increased, whereas EL reduced from wheat leaves over control. The Cd concentrations were reduced in wheat tissues and grains whereas Fe concentrations increased with Fe NPs application in a dose-additive manner. The current work suggested that the application of Fe NPs on wheat in Cd-contaminated soils could be employed to improve growth, yield and Fe biofortification as well as reduction in Cd concentrations in plants.
Assuntos
Cádmio/toxicidade , Compostos Férricos/farmacologia , Nanopartículas , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Antioxidantes/metabolismo , Biomassa , Cádmio/metabolismo , Clorofila/metabolismo , Compostos Férricos/química , Compostos Férricos/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Solo , Poluentes do Solo/metabolismo , Triticum/crescimento & desenvolvimento , Triticum/metabolismoRESUMO
Heavy metals are among the major environmental pollutants and the accumulation of these metals in soils is of great concern in agricultural production due to the toxic effects on crop growth and food quality. Phytoremediation is a promising technique which is being considered as an alternative and low-cost technology for the remediation of metal-contaminated soils. Solanum nigrum is widely studied for the remediation of heavy metal-contaminated soils owing to its ability for metal uptake and tolerance. S. nigrum can tolerate excess amount of certain metals through different mechanism including enhancing the activities of antioxidant enzymes and metal deposition in non-active parts of the plant. An overview of heavy metal uptake and tolerance in S. nigrum is given. Both endophytic and soil microorganisms can play a role in enhancing metal tolerance in S. nigrum. Additionally, optimization of soil management practices and exogenous application of amendments can also be used to enhance metal uptake and tolerance in this plant. The main objective of the present review is to highlight and discuss the recent progresses in using S. nigrum for remediation of metal contaminated soils.
Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Solanum nigrum/metabolismo , Biodegradação Ambiental , Metais Pesados/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Solanum nigrum/crescimento & desenvolvimentoRESUMO
Nickel (Ni) toxicity in agricultural crops is a widespread problem while little is known about the role of biochar (BC) and other organic amendments like farm manure (FM) from cattle farm and compost (Cmp) on its alleviation. A greenhouse experiment was conducted to evaluate the effects of BC, Cmp and FM on physiological and biochemical characteristics of maize (Zea mays L.) under Ni stress. Maize was grown in Ni spiked soil without and with two rates of the amendments (equivalent to 1% and 2% organic carbon, OC) applied separately to the soil. After harvest, plant height, root length, dry weight, chlorophyll contents, gas exchange characteristics and trace elements in plants were determined. In addition, post-harvest soil characteristics like pHs, ECe and bioavailable Ni were also determined. Compared to the control, all of the amendments increased plant height, root length, shoot and root dry weight with the maximum increase in all parameters by FM (2% OC) treatment. Similarly, total chlorophyll contents and gas exchange characteristics significantly increased with the application of amendments being maximum with FM (2% OC) application. Amendments significantly increased copper, zinc, manganese and iron concentrations and decreased Ni concentrations in the plants. The highest reduction in shoot Ni concentration was recorded with FM (2% OC) followed by BC (2% OC) being 73.2% and 61.1% lower compared to the control, respectively. The maximum increase in soil pH and decrease in AB-DTPA extractable Ni was recorded with BC (2% OC) followed by FM (2% OC). It is concluded that FM (2% OC) was the most effective in reducing Ni toxicity to plants by reducing Ni uptake while BC (2% OC) was the most effective in decreasing bioavailable Ni in the soil through increasing soil pH. However, long-term field studies are needed to evaluate the effects of these amendments in reducing Ni toxicity in plants.
Assuntos
Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Esterco , Níquel/toxicidade , Poluentes do Solo/toxicidade , Zea mays/efeitos dos fármacos , Animais , Bovinos , Clorofila/metabolismo , Fazendas , Níquel/análise , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/química , Solo/química , Poluentes do Solo/análise , Zea mays/fisiologia , Zinco/análiseRESUMO
This research introduces a novel dual-pathway convolutional neural network (DP-CNN) architecture tailored for robust performance in Log-Mel spectrogram image analysis derived from raw multichannel electromyography signals. The primary objective is to assess the effectiveness of the proposed DP-CNN architecture across three datasets (NinaPro DB1, DB2, and DB3), encompassing both able-bodied and amputee subjects. Performance metrics, including accuracy, precision, recall, and F1-score, are employed for comprehensive evaluation. The DP-CNN demonstrates notable mean accuracies of 94.93 ± 1.71% and 94.00 ± 3.65% on NinaPro DB1 and DB2 for healthy subjects, respectively. Additionally, it achieves a robust mean classification accuracy of 85.36 ± 0.82% on amputee subjects in DB3, affirming its efficacy. Comparative analysis with previous methodologies on the same datasets reveals substantial improvements of 28.33%, 26.92%, and 39.09% over the baseline for DB1, DB2, and DB3, respectively. The DP-CNN's superior performance extends to comparisons with transfer learning models for image classification, reaffirming its efficacy. Across diverse datasets involving both able-bodied and amputee subjects, the DP-CNN exhibits enhanced capabilities, holding promise for advancing myoelectric control.
Assuntos
Algoritmos , Amputados , Eletromiografia , Gestos , Redes Neurais de Computação , Processamento de Sinais Assistido por Computador , Extremidade Superior , Humanos , Eletromiografia/métodos , Extremidade Superior/fisiologia , Masculino , Adulto , Feminino , Adulto Jovem , Pessoa de Meia-Idade , Reprodutibilidade dos TestesRESUMO
Pesticides are becoming more prevalent in agriculture to protect crops and increase crop yields. However, nearly all pesticides used for this purpose reach non-target crops and remain as residues for extended periods. Contamination of soil by widespread pesticide use, as well as its toxicity to humans and other living organisms, is a global concern. This has prompted us to find solutions and develop alternative remediation technologies for sustainable management. This article reviews recent technological developments for remediating pesticides from contaminated soil, focusing on the following major points: (1) The application of various pesticide types and their properties, the sources of pesticides related to soil pollution, their transport and distribution, their fate, the impact on soil and human health, and the extrinsic and intrinsic factors that affect the remediation process are the main points of focus. (2) Sustainable pesticide degradation mechanisms and various emerging nano- and bioelectrochemical soil remediation technologies. (3) The feasible and long-term sustainable research and development approaches that are required for on-site pesticide removal from soils, as well as prospects for applying them directly in agricultural fields. In this critical analysis, we found that bioremediation technology has the potential for up to 90% pesticide removal from the soil. The complete removal of pesticides through a single biological treatment approach is still a challenging task; however, the combination of electrochemical oxidation and bioelectrochemical system approaches can achieve the complete removal of pesticides from soil. Further research is required to remove pesticides directly from soils in agricultural fields on a large-scale.
Assuntos
Agricultura , Biodegradação Ambiental , Recuperação e Remediação Ambiental , Praguicidas , Poluentes do Solo , Solo , Poluentes do Solo/análise , Praguicidas/análise , Praguicidas/química , Agricultura/métodos , Recuperação e Remediação Ambiental/métodos , Solo/química , HumanosRESUMO
Introduction: The increasing use of cerium nanoparticles (CeO2-NPs) has made their influx in agroecosystems imminent through air and soil deposition or untreated wastewater irrigation. Another major pollutant associated with anthropogenic activities is Cd, which has adverse effects on plants, animals, and humans. The major source of the influx of Cd and Ce metals in the human food chain is contaminated food, making it an alarming issue; thus, there is a need to understand the factors that can reduce the potential damage of these heavy metals. Methods: The present investigation was conducted to evaluate the effect of CeO2-10-nm-NPs and Cd (alone and in combination) on Zea mays growth. A pot experiment (in sand) was conducted to check the effect of 0, 200, 400, 600, 1,000, and 2,000 mg of CeO2-10 nm-NPs/kg-1 dry sand alone and in combination with 0 and 0.5 mg Cd/kg-1 dry sand on maize seedlings grown in a partially controlled greenhouse environment, making a total of 12 treatments applied in four replicates under a factorial design. Maize seedling biomass, shoot and root growth, nutrient content, and root anatomy were measured. Results and discussion: The NPs were toxic to plant biomass (shoot and root dry weight), and growth at 2,000 ppm was the most toxic in Cd-0 sets. For Cd-0.5 sets, NPs applied at 1,000 ppm somewhat reverted Cd toxicity compared with the contaminated control (CC). Additionally, CeO2-NPs affected Cd translocation, and variable Ce uptake was observed in the presence of Cd compared with non-Cd applied sets. Furthermore, CeO2-NPs partially controlled the elemental content of roots and shoots (micronutrients such as B, Mn, Ni, Cu, Zn, Mo, and Fe and the elements Co and Si) and affected root anatomy.
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The effects of foliar supply of silicon nanoparticles (Si-NPs) on growth, physiology, and cadmium (Cd) uptake by wheat (Triticum aestivum L.) were examined in different soil moisture levels. Seeds were sown in soil containing excess Cd (7.67 mg kg-1) and Si-NPs were applied through foliar dressing with various levels (0, 25, 50, 100 mg L-1) at different time intervals during growth period. Initially, all pots were irrigated with normal moisture level (70% water-holding capacity) and two moisture levels (35%, 70% WHC) were initiated after 6 weeks of plant growth for remaining growth duration and harvesting was done after 124 days of sowing. The results demonstrated the lowest plant growth, yield, and chlorophyll concentrations while the highest oxidative stress and Cd concentrations in plant tissues in water-stressed control (35% WHC) followed by normal control (75% WHC). Si-NPs enhanced the growth, photosynthesis, leaf defense system, and Si concentrations in tissues while minimized the Cd in wheat parts particularly in grains either soil normal or water-stressed conditions. Of the foliar spray, 100 mg L-1 of Si-NPs showed the best results with respect to growth, Cd and Si uptake by plants, and soil post-harvest bioavailable Cd irrespective of soil water levels. In grain, Cd concentration was below threshold limit (0.2 mg kg-1) for cereals in 100-mg kg-1 Si-NPs treatment irrespective of soil water levels. Si-NPs foliar dressing under Cd and water-limited stress might be an effective strategy in increasing growth, yield, and decreasing Cd concentration in wheat grains under experimental conditions. Thus, foliar dressing of Si-NPs minimized the Cd risk in food crops and NPs entry to surroundings, which might be possible after harvesting of crops in soil-applied NPs.
Assuntos
Nanopartículas , Poluentes do Solo , Cádmio/análise , Triticum , Silício/farmacologia , Poluentes do Solo/análise , Solo , Clorofila/farmacologia , Grão Comestível/química , ÁguaRESUMO
The present experiment was conducted to appraise the role of different seed priming agents in circumventing the negative impact of chromium (Cr) toxicity on canola plants. Chromium toxicity resulted in significant decline in photosynthetic pigments and growth attributes of two canola cultivars (Puriga and MS-007). Cr toxicity also resulted in higher oxidative stress mirrored as greater accumulation of hydrogen peroxide (H2O2) superoxide radical (O2â¢â), electrolyte leakage (EL) and malondialdehyde (MDA). Further, lipoxygenase enzyme activity that catalyzes the peroxidation of membrane lipids was also enhanced due to Cr toxicity. Canola plants also manifested impaired methylglyoxal (MG) detoxification due to the downregulation of glyoxalase enzymes (GlyI and II) under Cr stress. Seed priming treatments viz. osmo-priming with calcium chloride (CaCl2) and hormonal priming with salicylic acid (SA) remarkably improved growth and chlorophyll content in both canola cultivars under Cr toxicity as compared to other priming treatments such as hydro-priming, redox priming (H2O2) and chemical priming (Se; selenium). Moreover, CaCl2 and SA seed priming also resulted in lower oxidative stress and improved enzymatic (SOD, POD, CAT, APX, GR, GST) and non-enzymatic (GSH, phenolics, flavonoids, proline) antioxidant system of both cultivars under Cr toxicity. Further, hormonal and osmo-priming strengthened glyoxalase and antioxidant systems, thus improving reactive oxygen species (ROS) and MG detoxification. In this background, the cultivar Puriga is considered Cr tolerant as it exhibited better growth and lesser oxidative stress in both seed priming and non-primed conditions under Cr toxicity than cv. MS-007.
Assuntos
Brassica napus , Selênio , Antioxidantes/metabolismo , Cloreto de Cálcio , Cromo , Peróxido de Hidrogênio/farmacologia , Oxirredução , Estresse Oxidativo , Sementes/metabolismo , Selênio/farmacologiaRESUMO
Phosphorous (P) fixation in alkaline calcareous soils is a serious concern worldwide and acidified-biochar application has been proposed to improve the agronomic benefits of applied P. The present study aims to improve understanding of P transformation process in an alkaline soil following different biochar amendments (rice-husk biochar (RHB), sugarcane-bagasse biochar (SWB) and wheat-straw biochar (WSB)), chemically engineered (acidification with 1 N HCl or washing with distilled water (pristine biochar)) along with or without P at 60 mg kg-1. A pot experiment was conducted with three biochars (RHB, SWB, WSB) and control, two chemical modifications (acidic and pristine), and two P-levels (without or with P). A pot study by growing spring maize and a parallel incubation study were done to test the treatment effects on P transformation. Results demonstrated that acidified SBC and WSB increased the plant P uptake and dry-matter yield by 40% and 29.7%, respectively, with P-supply. Both pristine or acidified RHB produced 80.5% and 110.7%, more root dry-matter, respectively, compared to respective controls without P. Non-acidified WSB along with P showed significantly higher Olson's P in incubation study. While in case of acidification along with P addition, RHB exhibited greater P availability, but it was inconsistent at different times during incubation. It can be concluded that acidified biochar amendments have potential to improve P management with inconsistent results. It is difficult to rule out that acidification of biochars is a pre-requisite for alkaline soils for P improvement. Further research is needed to explore site-specific P management for sustainable crop production.
Assuntos
Poluentes do Solo , Solo , Disponibilidade Biológica , Carvão Vegetal , Fósforo , Poluentes do Solo/análise , Zea maysRESUMO
A field study was designed to explore the impacts of foliar-applied chemically and green synthesized titanium dioxide nanoparticles (TiO2 NPs) on cadmium (Cd) uptake in wheat plants. The wheat was grown in field which was contaminated with Cd and plants were subjected to foliar episodes of TiO2 NPs during plant growth period. Leaf extracts of two plant species (Trianthema portulacastrum, Chenopodium quinoa) were used for green synthesis while sol-gel method was used for chemical preparation of TiO2 NPs. Results showed that TiO2 NPs significantly enhanced the plant height, length of spikes photosynthesis, and straw and grain yield compared to control. TiO2 NPs minimized the oxidative burst in leaves and improved the enzyme activities than control. Cadmium concentrations of straw, roots and grains decreased after TiO2 NPs treatments than control. The grain Cd contents were below recommended threshold (0.2 mg Cd /kg grain DW) for cereals upon NPs exposure. The health risk index by the dietary use of grains for adults was below threshold upon NPs exposure. Overall, foliar use of TiO2 NPs prepared from plant extracts was appropriate in minimizing Cd contents in wheat grains, thereby reducing risk of Cd to human health via food chain.
Assuntos
Nanopartículas , Poluentes do Solo , Cádmio/análise , Cádmio/toxicidade , Humanos , Solo , Poluentes do Solo/análise , Titânio , TriticumRESUMO
Cadmium (Cd) availability in arable soils is a serious issue while little is known about the role of co-composted organic amendments and zinc oxide nanoparticles (ZnO-NPs) foliar spray on biomass and Cd accumulation in wheat grains. The current study investigated the soil application of organic amendment (composted biochar and farmyard manure) at a level of 0, 1, and 2% w/w and foliar spray of ZnO-NPs (0, 100, and 200 mg/L) on biomass, yield, and Cd in wheat grains cultivated in an aged Cd-contaminated agricultural soil. The results indicated that organic amendment increased the biomass, chlorophyll concentrations, yield, and activities of peroxidase and superoxide dismutase of wheat while decreased the electrolyte leakage and Cd concentrations in different parts of wheat such as shoots, roots, husks, and grains. This effect of organic amendment was further enhanced by the foliar spray of ZnO-NPs in a dose-additive manner. Cadmium concentration in grains was below threshold level (0.2 mg/kg DW) for cereals in combined application of 200 mg/L ZnO-NPs and 1% organic amendment as well as in higher treatment (2%) of organic amendment and NPs. Thus, combined use of organic materials and NPs might be a suitable way of reducing Cd and probably other toxic trace element concentrations in wheat and other cereals.
Assuntos
Nanopartículas , Poluentes do Solo/análise , Óxido de Zinco , Cádmio/análise , Solo , TriticumRESUMO
Wheat (Triticum aestivum L.) cultivation in cadmium (Cd) polluted soil is a core concern to food quality and food security all over the world. Cadmium toxicity is mainly associated with a Cd influx from contaminated soils to human via grain consumption. Organic amendments are widely used for Cd immobilization and enhancement in plant growth, but the residual effects of these amendments are mostly unknown. The present study addressed the long-term effects of organic amendments in contaminated soils by evaluating their residual effects on 3rd crop (wheat) in the sequence. Initially six organic amendments viz. rice husk biochar (RHB), wheat-straw biochar (WSB), cotton-stick biochar (CSB), poultry manure (PM), press mud (PrMd) and farm manure (FM) were applied once at a rate of 2% in Cd (50 mg kg-1) contaminated soil with wheat-rice rotation. After the harvest of wheat and rice crops, wheat (Var. Galaxy) was again grown in the same pots. Results revealed that plants grown under Cd stress (without any amendment) contain more tissue (root, shoot and grain) and soil AB-DTPA extractable Cd. The soil amended with RHB has shown lowest AB-DTPA extractable Cd (69% lower than control). Similarly, RHB application has significantly reduced wheat root, shoot and grain Cd concentrations compared to control and other amendments. Results have confirmed the effectiveness of RHB residual contents as an active amendment for restriction of Cd in non-bioavailable pool of soil and better growth and yield of wheat.
Assuntos
Cádmio/metabolismo , Poluentes do Solo/metabolismo , Triticum/metabolismo , Disponibilidade Biológica , Cádmio/análise , Carvão Vegetal , Produtos Agrícolas , Grão Comestível/química , Esterco , Oryza/crescimento & desenvolvimento , Solo , Poluentes do Solo/análise , Triticum/crescimento & desenvolvimentoRESUMO
Increasing cadmium (Cd) pollution in agricultural soils has raised serious concerns worldwide. Several exogenous substances can be used to mitigate the toxic effects of Cd in plants. Zinc (Zn) is one of the essential plant micronutrients and is involved in several physiological functions in plants. Zn may alleviate Cd toxicity in plants owing to the chemical similarity of Zn with Cd. Published reports demonstrated that Zn can alleviate toxic effects of Cd in plants by increasing plant growth, regulating Cd uptake, increasing photosynthesis, and reducing oxidative stress. Literature demonstrated that the role of Zn on Cd accumulation by plants is very controversial and depends upon several factors including concentrations of Cd and Zn in the medium, exposure duration, plant species and genotypes, and growth conditions. This review highlights the role of Zn in reducing Cd toxicity in plants and provides new insight that proper level of Zn in plants may enhance plant resistance to excess Cd.
Assuntos
Cádmio/toxicidade , Plantas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Zinco/farmacologia , Agricultura , Micronutrientes/farmacologia , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Desenvolvimento Vegetal/efeitos dos fármacos , SoloRESUMO
Food contamination with cadmium (Cd) is a serious health threat to humans worldwide and Cd accumulation by rice is a major source of Cd entrance to the food chain. Silicon (Si) application decreases the Cd content in rice but the timing of Si application may need further investigation. The present study investigated the effect of split application of Si in the soil (600 kg/ha of Si) at different growth stages of rice on the growth and Cd accumulation by rice under Cd stress. Rice plants were grown in the presence and absence of Cd and Si was applied in the soil at different growth stages of rice under Cd stress. The results indicated that Cd stress alone reduced the growth and photosynthesis and increased the Cd content in different tissues and grains of rice. Silicon application improved the plant growth and reduced the Cd accumulation, translocation factor, and bioaccumulation factor in rice especially in grains, whereas the response of Si varied with the application of Si at different growth stages. The application of Si in three splits (transplanting (S1), tillering (S2), panicle initiation (S3)) was the best in improving growth and reducing Cd concentrations in plants compared to other combinations of Si application. Silicon application in three splits (S1+S2+S3) reduced the grain Cd concentrations below the threshold level (0.2 mg/kg) and reduced the Cd health risk index under the experimental conditions. Overall, split application of Si at three growth stages may function as remediator and diminishes Cd uptake into rice grains.