The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Peng Wang - One of the best experts on this subject based on the ideXlab platform.
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defining appropriate methods for studying toxicities of trace metals in Nutrient Solutions
Ecotoxicology and Environmental Safety, 2018Co-Authors: Peng Wang, Neal W. Menzies, Peter M. KopittkeAbstract:The use of inappropriate experimental conditions for examining trace metal phytotoxicity results in data of questionable value. The present study aimed to identify suitable parameters for study of phytotoxic metals in Nutrient Solutions. First, the literature was reviewed to determine the concentration of six metals (Cd, Cu, Hg, Ni, Pb, and Zn) from solution of contaminated soils. Next, the effects of pH, P, Cl, NO3, and four Fe-chelators were investigated by using thermodynamic modelling and by examining changes in root elongation rate of soybean (Glycine max cv. Bunya). The literature review identified that the solution concentrations of metals in soils were low, ranging from (µM) 0.069-11Cd, 0.19-15.8 Cu, 0.000027-0.000079 Hg, 1.0-8.7 Ni, 0.004-0.55 Pb, and 0.4-36.3 Zn. For studies in Nutrient solution, pH should generally be low given its effects on solubility and speciation, as should the P concentration due to the formation of insoluble phosphate salts. The concentrations of Cl, NO3, and various chelators also influence metal toxicity through alteration of metal speciation. The Nutrient Solutions used to study metal toxicity should consider environmentally-relevant conditions especially for metal concentrations, with concentrations of other components added at levels that do not substantially alter metal toxicity.
Peter M. Kopittke - One of the best experts on this subject based on the ideXlab platform.
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defining appropriate methods for studying toxicities of trace metals in Nutrient Solutions
Ecotoxicology and Environmental Safety, 2018Co-Authors: Peng Wang, Neal W. Menzies, Peter M. KopittkeAbstract:The use of inappropriate experimental conditions for examining trace metal phytotoxicity results in data of questionable value. The present study aimed to identify suitable parameters for study of phytotoxic metals in Nutrient Solutions. First, the literature was reviewed to determine the concentration of six metals (Cd, Cu, Hg, Ni, Pb, and Zn) from solution of contaminated soils. Next, the effects of pH, P, Cl, NO3, and four Fe-chelators were investigated by using thermodynamic modelling and by examining changes in root elongation rate of soybean (Glycine max cv. Bunya). The literature review identified that the solution concentrations of metals in soils were low, ranging from (µM) 0.069-11Cd, 0.19-15.8 Cu, 0.000027-0.000079 Hg, 1.0-8.7 Ni, 0.004-0.55 Pb, and 0.4-36.3 Zn. For studies in Nutrient solution, pH should generally be low given its effects on solubility and speciation, as should the P concentration due to the formation of insoluble phosphate salts. The concentrations of Cl, NO3, and various chelators also influence metal toxicity through alteration of metal speciation. The Nutrient Solutions used to study metal toxicity should consider environmentally-relevant conditions especially for metal concentrations, with concentrations of other components added at levels that do not substantially alter metal toxicity.
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Prediction of Pb speciation in concentrated and dilute Nutrient Solutions
Environmental pollution (Barking Essex : 1987), 2007Co-Authors: Peter M. Kopittke, Colin J. Asher, Neal W. MenziesAbstract:Despite the presence of numerous studies in the literature examining the phytotoxicity of Pb, there is a lack of precise quantitative data on limiting concentrations of Pb for plant growth. Using the PhreeqcI chemical equilibrium model, simulations were conducted to examine the speciation of Pb in concentrated and dilute Nutrient Solutions. Due to the higher P concentration of Hoagland's solution (1000microM), precipitation of chloropyromorphite (Pb5(PO4)3Cl) was predicted to occur at lower pH values, and at lower Pb concentrations, than for a dilute Nutrient solution (2microM P). Although Nutrient Solutions prepared in the glasshouse were supersaturated (and Pb concentrations were substantially higher than predicted by modeling), they confirmed the importance of the P concentration in influencing the precipitation of Pb. Given the low solubility of Pb-phosphates, Nutrient Solutions with low P concentrations should be utilized, and plant growth should be related to measured Pb concentrations rather than to the quantity of Pb initially added.
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control of Nutrient Solutions for studies at high ph
Plant and Soil, 2005Co-Authors: Peter M. Kopittke, Neal W. MenziesAbstract:Little is known about factors effecting plant growth at high pH, with research often limited by the inability to separate nutritional deficiencies and HCO3- toxicity from the direct limitations imposed under high pH conditions. Various methods of controlling dilute Nutrient Solutions for studies at high pH were investigated. For short-term studies, it was found that a solution without Cu, Fe, Mn and Zn and aerated with CO2 depleted air, greatly reduced Nutrient precipitation at high pH, thus eliminating nutritional differences between treatments. Manual pH adjustment and the use of ion exchange resins as pH buffers were unsuitable methods of pH control. However, pH control by automated titration had little effect on solution composition while maintaining constant pH. The system described is suitable for studies in which the pH of the bulk Nutrient solution must be maintained. The system was used to examine OH- toxicity in mungbeans (Vigna radiata (L.) Wilczek cv. Emerald), with root length reduced at a bulk solution pH of 8.5 and greater.
Leo F. M. Marcelis - One of the best experts on this subject based on the ideXlab platform.
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Nutrient Solutions for Arabidopsis thaliana : A study on Nutrient solution composition in hydroponics systems
Plant methods, 2020Co-Authors: Sander H. Van Delden, Mohammad Javad Nazarideljou, Leo F. M. MarcelisAbstract:There is little information on the effect of Nutrient Solutions composition on Arabidopsis growth. Therefore, we compared growth performance of Arabidopsis thaliana (Col-0) grown on the most commonly used Nutrient Solutions in deep water culture: Hoagland and Arnon, Murashige and Skoog, Tocquin, Hermans, and Conn. In addition to these Nutrient solution composition experiments, we established Arabidopsis growth response curves for Nutrient solution concentration and salt stress (NaCl). Arabidopsis rosette fresh and dry weight showed an approximate linear decline with NaCl dose in deep water culture, i.e. 9% reduction relative to control per unit of electrical conductivity (EC in dS m−1, for scale comprehension 1 dS m−1 equals ~ 10 mM NaCl). The Tocquin, ½Hoagland and Conn Nutrient Solutions had equal and optimal growth performance. Optimal Nutrient solution concentration for Tocquin and Hoagland was 0.8 to 0.9 dS m−1. Close to the EC of ½Hoagland (1.1 dS m−1), which is frequently used in Arabidopsis research. Conn solution showed optimal growth at much higher EC (2 dS m−1) indicating that it is a balanced Nutrient solution that matches the needs of Arabidopsis. Full Murashige and Skoog solution (5.9 dS m−1) was lethal and diluted Solutions (EC of 1.6 and 1.1 dS m−1) caused stress symptoms and severe growth retardation at later developmental stages. Arabidopsis thaliana (Col-0) plants grown in deep water culture showed a sixfold growth difference when commonly used Nutrient Solutions were compared. Murashige and Skoog solution should not be used as Nutrient solution in deep water culture. Conn, Tocquin and ½Hoagland are balanced Nutrient Solutions which result in optimal Arabidopsis growth in hydroponic systems.
Neal W. Menzies - One of the best experts on this subject based on the ideXlab platform.
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defining appropriate methods for studying toxicities of trace metals in Nutrient Solutions
Ecotoxicology and Environmental Safety, 2018Co-Authors: Peng Wang, Neal W. Menzies, Peter M. KopittkeAbstract:The use of inappropriate experimental conditions for examining trace metal phytotoxicity results in data of questionable value. The present study aimed to identify suitable parameters for study of phytotoxic metals in Nutrient Solutions. First, the literature was reviewed to determine the concentration of six metals (Cd, Cu, Hg, Ni, Pb, and Zn) from solution of contaminated soils. Next, the effects of pH, P, Cl, NO3, and four Fe-chelators were investigated by using thermodynamic modelling and by examining changes in root elongation rate of soybean (Glycine max cv. Bunya). The literature review identified that the solution concentrations of metals in soils were low, ranging from (µM) 0.069-11Cd, 0.19-15.8 Cu, 0.000027-0.000079 Hg, 1.0-8.7 Ni, 0.004-0.55 Pb, and 0.4-36.3 Zn. For studies in Nutrient solution, pH should generally be low given its effects on solubility and speciation, as should the P concentration due to the formation of insoluble phosphate salts. The concentrations of Cl, NO3, and various chelators also influence metal toxicity through alteration of metal speciation. The Nutrient Solutions used to study metal toxicity should consider environmentally-relevant conditions especially for metal concentrations, with concentrations of other components added at levels that do not substantially alter metal toxicity.
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Prediction of Pb speciation in concentrated and dilute Nutrient Solutions
Environmental pollution (Barking Essex : 1987), 2007Co-Authors: Peter M. Kopittke, Colin J. Asher, Neal W. MenziesAbstract:Despite the presence of numerous studies in the literature examining the phytotoxicity of Pb, there is a lack of precise quantitative data on limiting concentrations of Pb for plant growth. Using the PhreeqcI chemical equilibrium model, simulations were conducted to examine the speciation of Pb in concentrated and dilute Nutrient Solutions. Due to the higher P concentration of Hoagland's solution (1000microM), precipitation of chloropyromorphite (Pb5(PO4)3Cl) was predicted to occur at lower pH values, and at lower Pb concentrations, than for a dilute Nutrient solution (2microM P). Although Nutrient Solutions prepared in the glasshouse were supersaturated (and Pb concentrations were substantially higher than predicted by modeling), they confirmed the importance of the P concentration in influencing the precipitation of Pb. Given the low solubility of Pb-phosphates, Nutrient Solutions with low P concentrations should be utilized, and plant growth should be related to measured Pb concentrations rather than to the quantity of Pb initially added.
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control of Nutrient Solutions for studies at high ph
Plant and Soil, 2005Co-Authors: Peter M. Kopittke, Neal W. MenziesAbstract:Little is known about factors effecting plant growth at high pH, with research often limited by the inability to separate nutritional deficiencies and HCO3- toxicity from the direct limitations imposed under high pH conditions. Various methods of controlling dilute Nutrient Solutions for studies at high pH were investigated. For short-term studies, it was found that a solution without Cu, Fe, Mn and Zn and aerated with CO2 depleted air, greatly reduced Nutrient precipitation at high pH, thus eliminating nutritional differences between treatments. Manual pH adjustment and the use of ion exchange resins as pH buffers were unsuitable methods of pH control. However, pH control by automated titration had little effect on solution composition while maintaining constant pH. The system described is suitable for studies in which the pH of the bulk Nutrient solution must be maintained. The system was used to examine OH- toxicity in mungbeans (Vigna radiata (L.) Wilczek cv. Emerald), with root length reduced at a bulk solution pH of 8.5 and greater.
Bowen Li - One of the best experts on this subject based on the ideXlab platform.
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Do Si/As ratios in growth medium affect arsenic uptake, arsenite efflux and translocation of arsenite in rice (Oryza sativa)?☆
Environmental Pollution, 2017Co-Authors: Min Zhang, Quanli Zhao, Shijie Zhang, Bowen LiAbstract:Abstract Silicon (Si) may decrease the uptake and accumulation of arsenic (As) in rice. However, the effects of Si/As ratios in growth medium on arsenic uptake, arsenite efflux to the external medium and translocation of arsenite in rice are currently unclear. Rice seedlings (Oryza sativa L.) were exposed to Nutrient Solutions with 10 μM arsenite [As(III)] or 10 μM arsenate [As(V)] to explore the influence of different silicic acid concentrations (0, 10, 100, 1000 μM) on arsenic uptake and translocation of arsenite with or without 91 μM phosphate for 24 h. Arsenic speciation was determined in Nutrient Solutions, roots, and shoots. In the arsenite treatments, different Si/As ratios (1:1, 10:1, 100:1) did not affect As(III) uptake by rice roots, however they did inhibit translocation of As(III) from roots to shoots significantly (P
