scholarly journals Silicon and Iron Differently Alleviate Copper Toxicity in Cucumber Leaves

Plants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 554 ◽  
Author(s):  
Dragana Bosnić ◽  
Predrag Bosnić ◽  
Dragana Nikolić ◽  
Miroslav Nikolić ◽  
Jelena Samardžić
Keyword(s):  
Copper Toxicity ◽  
Molar Ratio ◽  
Dramatic Decrease ◽  
Cucumis Sativus L ◽  
Molar Ratios ◽  
Cu Toxicity ◽  
Cu Accumulation ◽  
Cu Tolerance ◽  
Si Supply ◽  
Mn Concentrations

Copper (Cu) toxicity in plants may lead to iron (Fe), zinc (Zn) and manganese (Mn) deficiencies. Here, we investigated the effect of Si and Fe supply on the concentrations of micronutrients and metal-chelating amino acids nicotianamine (NA) and histidine (His) in leaves of cucumber plants exposed to Cu in excess. Cucumber (Cucumis sativus L.) was treated with 10 µM Cu, and additional 100 µM Fe or/and 1.5 mM Si for five days. High Cu and decreased Zn, Fe and Mn concentrations were found in Cu treatment. Additional Fe supply had a more pronounced effect in decreasing Cu accumulation and improving the molar ratio between micronutrients as compared to the Si supply. However, the simultaneous supply of Fe and Si was the most effective treatment in alleviation of Cu-induced deficiency of Fe, Zn and Mn. Additional Fe supply increased the His but not NA concentration, while Si supply significantly increased both NA and His whereby the NA:Cu and His:Cu molar ratios exceeded the control values indicating that Si recruits Cu-chelation to achieve Cu tolerance. In conclusion, Si-mediated alleviation of Cu toxicity was directed toward Cu tolerance while Fe-alleviative effect was due to a dramatic decrease in Cu accumulation.

scholarly journals Exogenous of Indole-3-Acetic Acid Application Alleviates Copper Toxicity in Spinach Seedlings by Enhancing Antioxidant Systems and Nitrogen Metabolism

Toxics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Qin Gong ◽  
Zhaohua Li ◽  
Ling Wang ◽  
Tongwei Dai ◽  
Qun Kang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Heavy Metal Contamination ◽  
Spinacia Oleracea ◽  
Antioxidant Systems ◽  
Cu Toxicity ◽  
Cu Accumulation ◽  
N Assimilation ◽  
Cu Tolerance ◽  
Indole 3 Acetic Acid ◽  
Exogenous Iaa

Indole-3-acetic acid (IAA) is a potential mediator in the protection of plants from copper (Cu) toxicity and the enhancement of Cu tolerance. In this paper, spinach (Spinacia oleracea L.) seedlings were cultivated in soil containing 700 mg kg−1 Cu and the leaves of seedlings were sprayed with different concentrations of IAA. Exogenous IAA treatment reduced the malondialdehyde (MDA) concentrations in Cu-stressed seedlings and increased biomass, proline content, and the activities of antioxidant enzymes. Exogenous IAA treatment also increased the levels of nitrogen (N) assimilation compounds and the activities of N-metabolizing enzymes, but reduced NH4+ content. Notably, lower concentrations of IAA (10–40 mg L−1) increased the Cu concentrations in roots and reduced the Cu concentrations in leaves, while higher concentrations of IAA (50 mg L−1) reduced the Cu concentrations in both roots and leaves to the lowest levels. The findings indicated that the application of IAA reduced Cu accumulation, alleviated Cu toxicity, and enhanced Cu tolerance in spinach seedlings. IAA application could be used as an alternative strategy for reducing Cu accumulation in vegetable crops and for remediating Cu-contaminated soil, in turn reducing the hazardous effects of heavy metal contamination on human health and the environment.

scholarly journals Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalyst Support ◽  
Oxidation Potential ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Optimum Parameters ◽  
Reduction Of Co2 ◽  
Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

scholarly journals Lipozyme 435-Mediated Synthesis of Xylose Oleate in Methyl Ethyl Ketone

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3317
Author(s):  
Maria Carolina Pereira Gonçalves ◽  
Jéssica Cristina Amaral ◽  
Roberto Fernandez-Lafuente ◽  
Ruy de Sousa Junior ◽  
Paulo Waldir Tardioli
Keyword(s):  
Oleic Acid ◽  
Methyl Ethyl Ketone ◽  
Molar Ratio ◽  
Methyl Ethyl ◽  
Sugar Ester ◽  
Molar Ratios ◽  
Emulsion Capacity ◽  
Ping Pong ◽  
Commercial Sugar ◽  
Repeated Use

In this paper, we have performed the Lipozyme 435-catalyzed synthesis of xylose oleate in methyl ethyl ketone (MEK) from xylose and oleic acid. The effects of substrates’ molar ratios, reaction temperature, reaction time on esterification rates, and Lipozyme 435 reuse were studied. Results showed that an excess of oleic acid (xylose: oleic acid molar ratio of 1:5) significantly favored the reaction, yielding 98% of xylose conversion and 31% oleic acid conversion after 24 h-reaction (mainly to xylose mono- and dioleate, as confirmed by mass spectrometry). The highest Lipozyme 435 activities occurred between 55 and 70 °C. The predicted Ping Pong Bi Bi kinetic model fitted very well to the experimental data and there was no evidence of inhibitions in the range assessed. The reaction product was purified and presented an emulsion capacity close to that of a commercial sugar ester detergent. Finally, the repeated use of Lipozyme 435 showed a reduction in the reaction yields (by 48 and 19% in the xylose and oleic acid conversions, respectively), after ten 12 h-cycles.

Appearance, corrosion properties, and leach resistance of spruce and pine wood treated with Mea modified micronized copper preservative (MCu)

Holzforschung ◽  
2014 ◽  
Vol 68 (4) ◽  
pp. 477-486 ◽  
Author(s):  
Myung Jae Lee ◽  
Sedric Pankras ◽  
Paul Cooper
Keyword(s):  
Wood Species ◽  
Wood Preservative ◽  
Molar Ratio ◽  
Corrosion Properties ◽  
Pine Wood ◽  
Molar Ratios ◽  
Copper Leaching ◽  
Mold Resistance ◽  
Refractory Wood

Abstract Canadian refractory wood species treated with micronized copper (MCu) wood preservative become mottled and streaky in appearance. To overcome this issue, the MCu system was modified by adding small amounts of monoethanolamine (Mea). The modified systems were evaluated to clarify the role of Mea in terms of leaching, corrosion, and mold resistance of MCu systems. The mottled and streaky surface on treated spruce was prevented at Mea/Cu molar ratios between 0.7 and 1.5. Copper leaching remained modest and was only slightly higher than that of MCu alone up to a Mea/Cu molar ratio of 1.2. However, adding even a small amount of Mea to the MCu formulation increased fastener corrosion compared with MCu. Protonated Mea increased as more Mea was added and was identified as the main corrosion-causing electrolyte in the system.

Hydrogen-bonded bent-core blue phase liquid crystal complexes containing various molar ratios of proton acceptors and donors

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 32319-32327 ◽  
Author(s):  
Chun-Chieh Han ◽  
Yu-Chaing Chou ◽  
San-Yuan Chen ◽  
Hong-Cheu Lin
Keyword(s):  
Liquid Crystal ◽  
Chain Length ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Chiral Center ◽  
Molar Ratio ◽  
Core Complex ◽  
Molar Ratios ◽  
Phase Liquid ◽  
Blue Phase

The molar ratio, alkyl chain length, lateral fluoro-substitution and the chiral center of H-bonded bent-core supramolecules would affect the BP ranges of BPLC complexes. H-bonded bent-core complex PIIIC9/AIIF* (3/7 mol mol−1) displayed the widest BPI range of ΔTBPI = 12 °C.

scholarly journals BrO/SO<sub>2</sub> molar ratios from scanning DOAS measurements in the NOVAC network

2013 ◽  
Vol 5 (2) ◽  
pp. 1845-1870 ◽  
Author(s):  
P. Lübcke ◽  
N. Bobrowski ◽  
S. Arellano ◽  
B. Galle ◽  
G. Garzón ◽  
...  
Keyword(s):  
Molar Ratio ◽  
Optical Absorption Spectroscopy ◽  
Short Term ◽  
Dynamic Changes ◽  
Volcanic System ◽  
Molar Ratios ◽  
Remote Sensing Technique ◽  
Field Campaigns ◽  
Term Field

Abstract. The molar ratio of BrO to SO2 is, like other halogen/sulphur ratios, a~possible precursor for dynamic changes in the shallow part of a volcanic system. While the predictive significance of the BrO/SO2 ratio has not been well constrained yet, it has the major advantage that this ratio can be readily measured using the remote-sensing technique Differential Optical Absorption Spectroscopy (DOAS) in the UV. While BrO/SO2 ratios have been measured during several short-term field campaigns this article presents an algorithm that can be used to obtain long-term time series of BrO/SO2 ratios from the scanning DOAS instruments of the Network for Observation of Volcanic and Atmospheric Change (NOVAC) or comparable networks. Parameters of the DOAS retrieval of both trace gases are given and the influence of co-adding spectra on the retrieval error will be investigated. Difficulties in the evaluation of spectroscopic data from monitoring instruments in volcanic environments and possible solutions are discussed. The new algorithm is demonstrated by evaluating data from the NOVAC scanning DOAS systems at Nevado del Ruiz, Colombia encompassing almost four years of measurements between November 2009 and end of June 2013. This dataset shows variations of the BrO/SO2 ratio several weeks prior to the eruption on 30 June 2012.

Structural characteristics of tetanolysin and its binding to lipid vesicles

1982 ◽  
Vol 152 (2) ◽  
pp. 888-892
Author(s):  
S Rottem ◽  
R M Cole ◽  
W H Habig ◽  
M F Barile ◽  
M C Hardegree
Keyword(s):  
Structural Characteristics ◽  
Lipid Vesicles ◽  
Molar Ratio ◽  
Molar Ratios ◽  
High Concentrations

Tetanolysin binding to lipid vesicles was found to depend on the molar ratio of cholesterol to phospholipid, being low in vesicles containing up to 20 mol% cholesterol and high in vesicles containing more than 33 mol%. High concentrations of purified tetanolysin preparations formed arc- and ring-shaped structures. The structures were not readily detectable in diluted preparations unless incubated with lipid vesicles containing high molar ratios of cholesterol to phospholipid. It is suggested that the toxin is concentrated on the vesicles to local concentrations high enough to form the arcs and rings.

scholarly journals Comprehensive characterization of humic-like substances in smoke PM<sub>2.5</sub> emitted from the combustion of biomass materials and fossil fuels

2016 ◽  
Vol 16 (20) ◽  
pp. 13321-13340 ◽  
Author(s):  
Xingjun Fan ◽  
Siye Wei ◽  
Mengbo Zhu ◽  
Jianzhong Song ◽  
Ping'an Peng
Keyword(s):  
Coal Combustion ◽  
Fossil Fuels ◽  
Solid Phase ◽  
Water Soluble ◽  
Total Carbon ◽  
Atmospheric Environment ◽  
Molar Ratio ◽  
Resonance Spectroscopy ◽  
Molar Ratios ◽  
Biomass Materials

Abstract. Humic-like substances (HULIS) in smoke fine particulate matter (PM2.5) emitted from the combustion of biomass materials (rice straw, corn straw, and pine branch) and fossil fuels (lignite coal and diesel fuel) were comprehensively studied in this work. The HULIS fractions were first isolated with a one-step solid-phase extraction method, and were then investigated with a series of analytical techniques: elemental analysis, total organic carbon analysis, UV–vis (ultraviolet–visible) spectroscopy, excitation–emission matrix (EEM) fluorescence spectroscopy, Fourier transform infrared spectroscopy, and 1H-nuclear magnetic resonance spectroscopy. The results show that HULIS account for 11.2–23.4 and 5.3 % of PM2.5 emitted from biomass burning (BB) and coal combustion, respectively. In addition, contributions of HULIS-C to total carbon and water-soluble carbon in smoke PM2.5 emitted from BB are 8.0–21.7 and 56.9–66.1 %, respectively. The corresponding contributions in smoke PM2.5 from coal combustion are 5.2 and 45.5 %, respectively. These results suggest that BB and coal combustion are both important sources of HULIS in atmospheric aerosols. However, HULIS in diesel soot only accounted for  ∼  0.8 % of the soot particles, suggesting that vehicular exhaust may not be a significant primary source of HULIS. Primary HULIS and atmospheric HULIS display many similar chemical characteristics, as indicated by the instrumental analytical characterization, while some distinct features were also apparent. A high spectral absorbance in the UV–vis spectra, a distinct band at λex∕λem ≈  280∕350 nm in EEM spectra, lower H ∕ C and O ∕ C molar ratios, and a high content of [Ar–H] were observed for primary HULIS. These results suggest that primary HULIS contain more aromatic structures, and have a lower content of aliphatic and oxygen-containing groups than atmospheric HULIS. Among the four primary sources of HULIS, HULIS from BB had the highest O ∕ C molar ratios (0.43–0.54) and [H–C–O] content (10–19 %), indicating that HULIS from this source mainly consisted of carbohydrate- and phenolic-like structures. HULIS from coal combustion had a lower O ∕ C molar ratio (0.27) and a higher content of [Ar–H] (31 %), suggesting that aromatic compounds were extremely abundant in HULIS from this source. Moreover, the absorption Ångström exponents of primary HULIS from BB and coal combustion were 6.7–8.2 and 13.6, respectively. The mass absorption efficiencies of primary HULIS from BB and coal combustion at 365 nm (MAE365) were 0.97–2.09 and 0.63 m2 gC−1, respectively. Noticeably higher MAE365 values for primary HULIS from BB than coal combustion indicate that the former has a stronger contribution to the light-absorbing properties of aerosols in the atmospheric environment.

The Control of the Reactions of Strontium Hexaferrite Formation by the Molar Ratio of Precursors

2007 ◽  
Vol 280-283 ◽  
pp. 471-472
Author(s):  
S.A. Seyyed Ebrahimi
Keyword(s):  
Critical Parameters ◽  
Molar Ratio ◽  
Strontium Hexaferrite ◽  
Strontium Oxide ◽  
Molar Ratios ◽  
Temperature Method ◽  
Wide Range ◽  
Method Of Production ◽  
Thermal Analysis Techniques

Strontium hexaferrite is one of the very important categories of magnetic materials with a wide range applications. One of the very critical parameters in the high temperature method of production of this material is molar ratio of iron oxide to strontium oxide. Although there could be found some reports on the effect of this parameter on the physical properties of the material in the literature but there are very few investigations about the role of this factor on the reactions occurred in the process. In this work the effect of different molar ratios of precursors on the reactions carried out for processing of strontium hexaferrite have been investigated by using thermal analysis techniques such as DTA/TG. Furthermore, the microstructure and the powder and bulk magnetic properties of the products have been studied by SEM, VSM and permeameter.

scholarly journals The effect of pH on copper toxicity to hydroponically grown maize.

1981 ◽  
Vol 29 (3) ◽  
pp. 217-238 ◽  
Author(s):  
T.M. Lexmond ◽  
P.D.J. van der Vorm
Keyword(s):  
Root Growth ◽  
Toxic Effect ◽  
Copper Toxicity ◽  
Effect Of Ph ◽  
Cu Toxicity ◽  
Hydroponically Grown

The effect of pH on Cu toxicity in maize cv. Capella was studied in 3 sol. culture experiments of different design. Raising the pH intensified the toxic effect of Cu which reduced root growth and enhanced association of Cu2+ ions with physiologically essential sites in the roots when competition from protons was lowered. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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