Increasing Copper Content Research Articles

Electrodeposited Ni-Cu alloy coatings on mild steel for enhanced corrosion properties

Ni rich single-phase Ni-Cu alloy coatings were obtained on mild steel substrates by electrodeposition from stable alkaline citrate baths. Three different baths were prepared with varying Cu2+ concentration. Electrodeposition experiments were performed in the galvanostatic mode at three different current densities of 10, 20 and 30 mA cm−2. The coating compositions calculated from EDAX analysis showed that copper content in the coating increased with an increase in copper content of the bath, but decreased with an increase in current density. It was observed that the morphology of the deposits changed from globular to cauliflower with an increase in current density. Deposits from baths containing lower copper content showed more separated and localised cauliflower structures. The roughness of the deposits was also observed to increase with an increase in current density and to some extent with increase in deposition time. The corrosion potential for all coatings was less negative compared to mild steel, indicating barrier protection properties. Corrosion rate was largely affected by the morphology and roughness of the coatings. At higher current densities and higher deposition time, rougher surfaces and gaps and separations between the cauliflower structures were responsible for higher corrosion rate.

Osteogenic, Angiogenic, and Antibacterial Bioactive Nano-Hydroxyapatite Co-Synthesized Using γ-Polyglutamic Acid and Copper.

Nano-antibacterial calcium phosphate (CaP) has attracted intense attention with regard to its wide variety of medical and biological applications. The γ-polyglutamic acid and copper cosynthesized hydroxyapatite (γ-PGA/CuxHAp) was synthesized using the wet method. Structural and chemical characterizations demonstrate that copper was quantitatively incorporated into the hydroxyapatite structure, and the degree of Cu substitution was up to 20 mol % in the synthesized nanocrystals. Morphology characterization showed that the size of the γ-PGA/CuxHAp nanoparticles decreases with the increased copper content. γ-PGA/CuxHAp exhibited a steady release of Cu ions. Two experimental protocols were applied to compare the antibacterial activity of the γ-PGA/CuxHAp samples. A positive correlation was observed between Cu content and the inhibition of bacterial growth. The study also showed that nanoparticles with smaller particle sizes exhibited higher antibacterial activities than the larger particles. Endothelial and osteoblast cells rapidly proliferated on γ-PGA/CuxHAp, whereas high concentrations (20 mol %) of Cu ions reduced cell proliferation. In the rat calvarial defect model, some γ-PGA/CuxHAp samples such as γ-PGA/CuxHAp (x = 8, 16) showed efficient bone regeneration capacities at 12 weeks post implantation. Thus, the multibiofunctional γ-PGA/CuxHAp nanocomposite exhibited degradative, angiogenic, bactericidal and bone regenerative properties, providing a potential means to address some of the critical challenges in the field of bone tissue engineering.

Changes of the Nitric Oxide and Copper Content in the Olfactory Bulbs of Rat Brain After Modeling of Brain Stroke and Intranasal Administration of Mesenchymal Stem Cells

A comparative experimental analysis by EPR spectroscopy of the intensity of nitric oxide (NO) production and the content of the copper in the tissues of olfactory bulb of the brain of male Wistar rats were performed after modeling of ischemic stroke and treatment with immediate intranasal injection of mesenchymal stem cells (MSCs). Brain ischemia was simulated by ligation at the level of bifurcation of the common carotid arteries. It was found a significant reduction of NO content in the olfactory bulb of the brain of rats on the 1st and 2nd days after modeling of ischemia. The level of NO production was also reduced on the 1st and 2nd days after ischemia with MSCs’ administration as compared to intact animals. It was not found the significant difference of the NO content in rats after ischemia with MSCs’ administration relative to ischemic rats. The copper content in the olfactory bulb of the rat, which corresponds to the level of superoxide dismutase 1 and 3, tended to increase after modeling ischemia and remained for 2 days. The MSCs’ administration was accompanied by a significant increase in copper content on the 1st day after modeling of ischemia and by decrease of its content on 2nd day after ischemia. The experiments showed that MSCs’ administration did not affect the intensity of NO production on the 1st and 2nd days after the modeling of brain ischemia, but was accompanied by an increase in the antioxidant protection of the nervous tissue 1 day after ischemia.

In vitro studies of solution precursor plasma-sprayed copper-doped hydroxyapatite coatings with increasing copper content.

In this present study, in vitro characterization on bioactivity and biocompatibility of the copper-doped hydroxyapatite (Cu-HA) coatings deposited onto Ti6Al4V alloy with increasing copper content obtained using solution precursor plasma spray process were evaluated under simulated body fluid (SBF) and cytotoxicity tests. The growth of flake-like structures was observed at the coatings' surface after 7 days of immersion in SBF. Elemental composition analysis showed a calcium-deficient carbonate-containing apatite for the grown layer. Broadening of the HA peaks were also observed in the X-ray diffraction patterns and infrared absorption spectra of the immersed coatings associated with the possible formation of an amorphous layer at the surface of the coatings. Copper incorporation does not alter the bioactivity of HA but only slowed down for 10 mol% copper content. Cytotoxicity evaluation using MTT assays showed that 3 mol% Cu-HA coating was not toxic under in vitro characterizations.

Surface-plasmon-resonance induced photocatalysis by Cu(0)/Cu(II)@g-C3N4/MCM-41 nanosphere towards phenol oxidation under solar light

A series of ternary Cu(0)/Cu(II)@g-C3N4/MCM-41 composites have been fabricated by varying the different weight percentage of Cu (2, 4, 6 and 8) with the help of wetness impregnation and thermal condensation methods. The different characterization techniques were adopted to evaluate the morphological studies of as prepared composites provides a better support to distribute g-C3N4 on its surface. Again copper was impregnated onto the surface of g-C3N4/MCM-41 surface as co-catalyst. With increase in copper content, it reduces from Cu(II) to Cu(0) without using a reducing agent. The presence of g-C3N4 helps to shift the Fermi level of CuO towards more negative values due to accumulation of photogenerated electrons on the surface of Cu nanoparticle. Due to the surface plasmon resonance effect of Cu(0), more polarized light was absorbed by the composite and also favours charge separation by creating a Schottky barrier at the junction. The 4 wt% Cu loaded over g-C3N4/MCM-41 exhibits highest percentage of phenol oxidation (97%) under visible light irradiation with different byproduct like benzoquinone (BQ), hydroquinone (HQ) and catechol (CT) with selectivity of 92%, 3% and 2% respectively. The enhancement in catalytic activity has been explained on the basis of synergism between g-C3N4 and Cu(II) and the SPR effect of Cu(0) which also acts as a co-catalyst present on the surface.

Assessment of Serum Zinc and Copper Levels, and Cu / Zn Ratio Among Patients of Côte D’Ivoire with Type 2 Diabetes

Type 2 diabetes or diabetes mellitus is a metabolic disorder characterized by an increase in blood sugar level. It is caused by a lack of insulin secretion, insulin action, or both. There are approximately 501,530 people living with diabetes in Cote d’Ivoire with an estimated prevalence of 5.19% in 2013. Unfortunately impairment of zinc and copper leads to increased oxidative stress, insulin resistance and diabetic complications. The study aimed to assess the zinc and copper status in patients with type 2 diabetes. This study involved 80 type 2 diabetics and 80 non-diabetic as controls. Glycated hemoglobin (HbA1c) was analyzed in whole blood using the Hitachi Roche Cobas C311. The serum assays of zinc and copper then of glycemia were carried out using a flame-air / acetylene atomic absorption spectrophotometer (AAS) of the brand Varian Spectr AA-20 Victoria, Australia and on the Cobas C311 respectively. A significant decrease in zinc content (P ˂ 0.0001) and a significant increase in copper content as well as the Cu / Zn ratio (P ˂ 0.0001) were observed in type 2 diabetic patients compared to non-diabetic control. The lower serum zinc values and the high Cu / Zn ratio could justify the high level of oxidative stress in patients with type 2 diabetes. Assessment of zinc and copper is essential in the monitoring of complications due to type 2 diabetes.

Preparation of TiC based Cermet with Different Ratio of Cu and Al

TiC based cermet belongs to superhard tool material, which has high melting point, high hardness and excellent chemical stability. It is the preferred material for cutting tools and wear-resistant components. At the same time, it has excellent conductivity and is also the preferred material for electrode. In this experiment, TiC based cermet was prepared by atmosphere protection sintering method with TiC, Cu and Al as raw materials. The phase analysis was carried out by X-ray diffractometer(XRD), the microstructure was observed by scanning electron microscope (SEM), the element analysis was carried out by energy spectrometer, and the bending strength was tested by universal material tester. The different sintering temperature and the ratio of additive Cu and Al were systematically studied under the premise of controlling the total mass of TiC based cermet, which effect on microstructure and mechanical properties of TiC based cermet. The experimental results show that the bending strength of cermet increases obviously with the increase of copper content in a certain range, and the best mechanical properties of cermet are obtained when the ratio of Cu and Al is 6:4. With the increase of sintering temperature, the mechanical properties of TiC based cermet are significantly strengthened. When the sintering temperature reaches 1100 °C, the grain size is fine and uniform, and the comprehensive properties of the material are the best.

Установление границ допустимого содержания химических элементов в шерсти представителей семейства Хомяковые Cricetidae с применением центильных шкал

The aim of the study was to study the content of some heavy metals and arsenic in members of the Cricetidae family of hamsters and to develop centile scales for assessing the level of accumulation of these elements for the Central Federal District. In 2018–2020, hamster`s wool was studied for the accumulation of zinc, copper, iron, lead, cadmium and arsenic by the atomic absorption method. The data on the characteristics of the content of chemical elements in different sexes of animals are given. In the course of the study, it was found that, according to the value of the average content in the wool of animals of the family, the studied elements form the following decreasing series: Fe> Zn> Pb> Cu> Cd> As. When studying the features of the accumulation of chemical elements by different sexes, a significant increase in the concentration of zinc, iron, cadmium and arsenic in the wool of males was established, compared with females, depending on the species, from 1,38 to 3,98; from 1,28 to 1,52; from 2,00 to 304,00 times, respectively. With regard to the accumulation of copper in the body, the opposite trend is observed. In females, its concentration is 1,5–3,19 times higher. In the studied sample of animals, an increase in copper content was revealed in 44,83% of individuals and a decrease in cadmium in 44,82%.

Microstructure, Wettability, Corrosion Resistance and Antibacterial Property of Cu-MTa2O5 Multilayer Composite Coatings with Different Cu Incorporation Contents.

Bacterial infection and toxic metal ions releasing are the challenges in the clinical application of Ti6Al4V alloy implant materials. Copper is a kind of long-acting, broad-spectrum and safe antibacterial element, and Ta2O5 has good corrosion resistance, wear-resistance and biocompatibility, they are considered and chosen as a potential coating candidate for implant surface modification. In this paper, magnetron sputtering technology was used to prepare copper doped Ta2O5 multilayer composite coating Cu-Ta2O5/Ta2O5/Ta2O5-TiO2/TiO2/Ti (Cu-MTa2O5 for short) on Ti6Al4V alloy surface, for studying the effect of copper incorporation on the microstructure, wettability, anticorrosion and antibacterial activities of the composite coating. The results showed that Cu-MTa2O5 coating obviously improves the hydrophobicity, corrosion resistance and antibacterial property of Ti6Al4V alloy. In the coating, both copper and Ta2O5 exhibit an amorphous structure and copper mainly presents as an oxidation state (Cu2O and CuO). With the increase of the doping amount of copper, the grain size, roughness, and hydrophobicity of the modified surface of Ti6Al4V alloy are increased. Electrochemical experiment results demonstrated that the corrosion resistance of Cu-MTa2O5 coated Ti6Al4V alloy slightly decreased with the increase of copper concentration, but this coating still acts strong anticorrosion protection for Ti6Al4V alloy. Moreover, the Cu-MTa2O5 coating can kill more than 97% of Staphylococcus aureus in 24 h, and the antibacterial rate increases with the increase of copper content. Therefore, Cu-MTa2O5 composite coating is a good candidate for improving anticorrosion and antibacterial properties of Ti6Al4V alloy implant medical devices.

Leaching Kinetics of Arsenic Sulfide-Containing Materials by Copper Sulfate Solution

The overall decrease in the quality of mineral raw materials, combined with the use of arsenic-containing ores, results in large amounts of various intermediate products containing this highly toxic element. The use of hydrometallurgical technologies for these materials is complicated by the formation of multicomponent solutions and the difficulty of separating copper from arsenic. Previously, for the selective separation of As from copper–arsenic intermediates a leaching method in the presence of Cu(II) ions was proposed. This paper describes the investigation of the kinetics of arsenic sulfide-containing materials leaching by copper sulfate solution. The cakes after leaching of arsenic trisulfide with a solution of copper sulfate were described using methods such as X-ray diffraction spectrometry (XRD), X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy analysis (EDS). The effect of temperature (70–90 °C), the initial concentration of CuSO4 (0.23–0.28 M) and the time on the As recovery into the solution was studied. The process temperature has the greatest effect on the kinetics, while an increase in copper concentration from 0.23 to 0.28 M effects an increase in As transfer into solution from 93.2% to 97.8% for 120 min of leaching. However, the shrinking core model that best fits the kinetic data suggests that the process occurs by the intra-diffusion mode with the average activation energy of 44.9 kJ/mol. Using the time-to-a-given-fraction kinetics analysis, it was determined that the leaching mechanism does not change during the reaction. The semi-empirical expression describing the reaction rate under the studied conditions can be written as follows: 1/3ln(1 − X) + [(1 − X) − 1/3 − 1] = 4560000Cu3.61e−44900/RT t.

The counter defence system of antioxidants in Coelomycetous emerging human and plant pathogenic fungus Macrophomina phaseolina against copper toxicity.

Macrophomina phaseolina (Tassi) Goid. is primarily a phytopathogen but also exhibits potential to cause infection in human being due to its aggressive and robust nature. Adaptation potential in M. phaseolina was assessed after exposing to heavy metal copper through analysing macro- and microscopic as well as physiological attributes. Considerable modifications were observed in morphology with an increase in concentrations (25, 75, and 100ppm) of copper as compared with control. Total content of protein and activities of the antioxidant enzymes were affected differently at different copper concentrations. The fungal biomass, metal accumulation, metal uptake efficiency, and bioaccumulation factors were decreased due to the increase in copper concentrations. Fourier transformed infrared spectroscopic assessment showed hydroxyl, carboxyl, and amine groups as major metal accumulation sites. It is concluded that Cu-based fungicides can manage this pathogen but excessive application may accumulate in the plant that will transfer along the food chain, reaching ultimately the human body.

Effect of copper on microstructure, recrystallization and precipitation kinetics in strip cast low carbon steel

Strip cast samples with different copper content have been developed by simulated direct strip casting. The as-cast microstructures were characterized by optical microscopy and electron microscopy. The microstructures mainly consisted of polygonal ferrite and Widmanstatten ferrite in as cast condition. X-ray diffraction showed that the copper was in solid solution in the as-cast condition. It was found that the equivalent tensile yield and maximum strengths, both increased with an increase in copper content. The strip cast samples were cold rolled to 70% reduction and then annealed isothermally at 600, 650 and 700 °C for various times to study the recrystallization and precipitation kinetics. After annealing, the hardness and strength were found to be decreased due to recovery and recrystallization. It was found that an increase in copper content retarded the recrystallization kinetics. During annealing, precipitation of copper was observed. The copper precipitates were bimodal with respect to particle size and distribution. The size and spacing of the particles were measured and the Zener pinning effect of the particles was calculated. High pinning forces of more than 2 MPa were predicted, and this correlated well with the observed decrease in recrystallization kinetics.

Investigating the impact of copper leaching on combustion characteristics and particulate emissions in HPCR diesel engines

Copper leaching in diesel fuel and its impact on combustion and emission characteristics of a Direct Injection High Pressure Common Rail (DI HPCR) diesel engine was investigated. This work was performed using a single cylinder Ricardo Hydra research engine fitted with a cylinder head, piston assembly, and crankshaft from a production 2.2 L DI diesel engine. A fuel conditioning device consisting of a helicoidally shaped copper duct and electromagnetic coils powered from the battery was installed along the fuel line just before the high pressure pump. A diesel fuel with a copper content of less than 0.2 ppm was used. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed an increase of copper content to 1 ppm when fuel flowed through the conditioning device prior to the injection and returned from the engine back to the fuel tank. Copper leaching from the conditioning device was confirmed using a bespoke test rig. Combustion characteristics were analysed via post-processing pressure measurements, while an AVL Smoke Meter was used to monitor particulate emissions. A pilot plus main strategy was used to achieve a target Brake Mean Effect Pressure (BMEP) typical of medium load. Soot reduction in the range of 7–14% was measured when the device was connected to the fuel line, compared to the baseline. The initiation and early development of combustion was also investigated using an unstirred, quiescent combustion chamber with optical access. High-speed photography showed that ignition probability was enhanced in presence of the fuel conditioning device.

Effect of heat processing on the nutrient composition, colour, and volatile odour compounds of the long-horned grasshopper Ruspolia differens serville.

Heat processing is commonly used to prepare edible insects for consumption. This study aimed at determining the effect of boiling and subsequent oven roasting on Ruspolia differens' nutrient composition, colour and odor compounds. Boiling leads to: a significant increase in protein and decrease in fat content on a dry matter basis; a minimal influence on its amino and fatty acids profile; a significant reduction in its ash content due to leaching of phosphorus, potassium and sodium; a significant increase in iron, zinc, copper, manganese and calcium content; and a fivefold reduction in the amount of vitamin B12. Roasting leads to a relative increase in the amount of calcium and trace mineral elements but doesn't affect other nutrients. Roasting results into a more uniform colour intensity when green and brown polymorphs are roasted together. Lipid oxidation is responsible for the colour and aroma of heat processed R. differens.

Sublethal effects of waterborne copper and copper nanoparticles on the freshwater Neotropical teleost Prochilodus lineatus: A comparative approach

Copper nanoparticles can contaminate the aquatic environment, but their effects on fish and how they may differ from copper salts is not understood. Thus, in this work we compare the sublethal effects of copper nanoparticles (nCu) and copper chloride (Cu) on the freshwater teleost Prochilodus lineatus, known for its sensitivity to copper. Juveniles (n = 8/group) were exposed to 20 μg L−1 of copper as CuCl2 (Cu), 40 μg L−1 of copper nanoparticles (nCu), or only water (control), for 96 h. These concentrations were chosen to achieve similar dissolved copper concentration in both treatments (Cu: 10.29 ± 0.94 μg L−1; nCu: 12.16 ± 1.77 μg L−1). After the exposure, the following biological parameters were evaluated: copper accumulation in the gills, liver, gastrointestinal tract, kidney, and muscle; hematocrit (Ht) and hemoglobin content (Hb); branchial activity of Na+-K+-ATPase (NaKATP), H+-ATPase (HATP), Ca2+-ATPase (CaATP), and carbonic anhydrase (CA); glutathione content (GSH) and lipid peroxidation (LPO) in the liver; acetylcholinesterase activity (AChE) in the brain and muscle; and histopathology of the gills and liver. The gills of Cu-exposed fish were adversely affected, with increased copper content, inhibition of H+-ATPase and Ca2+-ATPase, and histological damage, including proliferation of mitochondria rich cells and/or mucous cells. In addition, LPO levels increased in the liver of Cu-exposed fish, indicating the occurrence of oxidative stress. Exposure to nCu promoted a decrease in Ht and Hb, indicating anemia, and an increase in branchial Na+-K+-ATPase and H+-ATPase activities, which can be an adaptive response to metabolic acidosis. Within the chosen biomarkers and the conditions tested, copper nanoparticles were less toxic than copper. However, the effects promoted by the nanoparticles were different from those promoted by copper. These results emphasize the need for a better understanding of copper nanoparticles toxicity in order to establish safe concentrations and avoid environment impacts.

Cu-Ce-La-Ox as efficient CO oxidation catalysts: Effect of Cu content

Nanograins of Ce-La-xCu-O mixed metal oxides (wherex = 3, 5, 7, 10, 20 at.%), of approximately 16 nm2 area size, and having all the metal cations homogeneously distributed, are tested as ternary catalytic materials towards the CO oxidation in the 100–475 °C range. Preservation of the cubic ceria lattice structure in those catalysts following La3+ (heavy) and Cu2+ (light) metal cations doping is confirmed based on the powder X-ray diffraction and Raman shift studies. From X-ray photoelectron spectroscopy studies, the presence of mixed Ce3+/Ce4+ and Cu2+/Cu1+ oxidation states was confirmed, which was more profound in the low Cu-content Ce-La-xCu-O catalysts. The copper doping is also found to increase the concentration of oxygen vacant sites in the doped-CeO2 solid as demonstrated from the increase of the Raman intensity ratio IOv/IF2g of 1.58 and 1.78 with the increase in copper content from 7 to 20 at.% as compared to the lower value of 0.44 obtained for the Cu-free catalyst (Ce-La). The mobility of the surface and bulk oxygen ions in the lattice of such doped-CeO2 materials is further investigated using 16O/18O transient isothermal isotopic exchange (TIIE) experiments, and is found to be Cu at.% dependent. For the case of Ce-La-20Cu, the participation of the lattice oxygen (OL) in the reaction mechanism has been demonstrated using transient experiments. Accordingly, the specific rate (μmol CO m−2s−1) of the CO oxidation reaction is found to be higher for the Ce-La-20Cu and Ce-La-7Cu catalysts, corroborating thus the presence of more mobile/labile oxygen species in those ternary catalysts as opposed to the other lower copper compositions.

Investigation on the structural and optical properties of copper doped NiO nanostructures thin films

Abstract In this research, copper is doped NiO nanostructures thin films by using various doping compositions (2, 4, 6 & 8%) have been prepared by chemical spray pyrolysis technique at a temperature of (400 °C). The optical, morphological and structural properties were investigated using UV–visible spectrophotometry, X-Ray diffraction (XRD) and atomic force microscopy (AFM). The results of (XRD) showed that all the prepared films are polycrystalline in nature with cubic structure with a strong (1 1 1) preferred orientation and the average crystallite size decreased with increase copper concentration, while the results of (AFM) indicate that the roughness of the surface decrease with increase doping. Enhancement of optical transmittance with doping decrease in the range (300–900 nm) was observed, and the absorption coefficient increased by increasing doping ratio, while the optical energy gap for allowing direct transmission decreased in the range (3.31 to 2.94 eV).

Copper Toxicity and Prediction Models of Copper Content in Leafy Vegetables

Copper (Cu), a toxic metal pollution found in the soil and water of industrialized areas, causes continuous issues for agriculture product contamination and human health hazards. However, information on copper phytotoxicity and its accumulation in vegetables is largely unknown. To evaluate the related agricultural loss and health risks, it is necessary to assess copper phytotoxicity and develop prediction models for copper concentration in vegetables. Here, we assess the growth performance and copper concentration of four leafy vegetables: Water spinach, amaranth, pakchoi, and garland chrysanthemum in copper-contaminated soil. The plant’s height and fresh weight is dramatically reduced when the soil copper concentration is over ~250 mg·kg−1. This yield reduction and copper accumulation are associated with an increase of soil copper concentration, suggesting high copper phytotoxicity levels in plants and soil. The prediction models of plant copper concentration were developed using multiple regressions based on one-step extractions of the soil copper as independent variables. One prediction model derived for amaranth copper using hydrochloric acid (HCl)-extractable and ethylenediaminetetraacetic acid (EDTA)-extractable copper from soil is able to describe 78.89% of the variance in the measured copper. As a result, the phytotoxic copper level for four leafy vegetables is revealed. Although the prediction models may not be universal, the predicted and phytotoxic copper levels are useful tools for evaluating vegetable yield and daily copper intake.

Copper oxide nanoparticles alter cellular morphology via disturbing the actin cytoskeleton dynamics in Arabidopsis roots

Copper oxide nanoparticles (CuO NPs) have severe nano-toxic effects on organisms. Limited data is available on influence of CuO NPs on plant cells. Here, the molecular mechanisms involved in the toxicity of CuO NPs are studied. Exposure to CuO NPs significantly increased copper content in roots (0.062–0.325 mg/g FW), but CuO NPs translocation rates from root to shoot were low (1.1–2.8%). Presented data were significant at p < 0.05 compared to control. CuO NPs inhibited longitudinal growth and promoted transverse growth in root tip cells. However, CuO NPs did not affect the leaf cells, implying that the transfer ability of CuO NPs was weak, and toxicity mainly affected roots. CuO NPs can conjugate with actin protein. The actin cytoskeleton experienced reorganization in the presence of CuO NPs. The longitudinal filamentous actin (F-actin) decreased, and the transverse F-actin increased. CuO NPs inhibited actin polymerization and promoted depolymerization. The behavior of individual F-actin was at steady state with time-lapse under CuO NPs treatment by time-lapse reflection fluorescence (TIRF) microscopy. The growth rate of actin filaments was weakened by CuO NPs. CuO NPs disturbed the subcellular localization of PINs and the gradient of auxin distribution in root tips in an actin-dependent manner. In conclusion, CuO NPs conjugated with actin and disturbed F-actin dynamics, triggering abnormal cell growth in the root tip, and findings provide theoretical basis for further study nano-toxicity in plants.

Excess Copper-Induced Changes in Antioxidative Enzyme Activity, Mineral Nutrient Uptake and Translocation in Sugarcane Seedlings.

Sugarcane is a potential species for use in heavy metal remediation. To analyze the effect of excess copper on sugarcane, the biomass, mineral nutrient content and activities of antioxidative enzymes were measured under copper stress. The results revealed that the biomass of roots and shoots significantly decreased with increasing copper concentration in solution. Most copper accumulated in the roots, and the translocation factor of copper decreased with an increase in copper stress. The MDA content in sugarcane roots notably increased under copper stress. The POD activity in sugarcane roots increased, and CAT activity decreased under copper stress. The Zn, Fe and Mn contents in shoots increased significantly under 200μmolL-1 Cu2+ treatments. The Zn and Mg contents in roots notably decreased under copper stress, while the Zn and Mg translocation factors increased. These results indicated that the increase in POD activity and the modification of mineral nutrient uptake and transfer might play an important role in reducing the detrimental effects of excess copper.