Amir Fotovat

Previous studies on the difference in accumulation and translocation of cadmium (Cd) among different wheat cultivars have typically focused on a small number of cultivars or used a culture medium with a single Cd level while selecting a specific plant vegetative stage. However, the present study aimed to assess the effect of the mentioned factors on the uptake, translocation, and accumulation of this toxic element among ten wheat cultivars grown in soil with three levels of Cd (0, 10, and 20 mg kg-1). The cultivars included five spring bread wheat (Triticum aestivum L.) (Pishgam, Sirvan, Rakhshan, Talaei, and Parsi) and five spring durum wheat (Triticum durum Desf.) (Behrang, Hana, Aran, Shabrang, and Sana). At maturity, plant organs were harvested and digested by the wet oxidation method (using nitric acid and hydrogen peroxide). Then, the concentrations of the metal in grain, leaves, stem, and root were determined. Moreover, translocation Factors from shoot to grain (TFG: Sh) and root to grain (TFG: R) were calculated for the cultivars. The results revealed that different wheat cultivars exhibited varying behaviors in Cd absorption and transfer at each level of soil contamination. TFG:Sh seems to be the main agent for the difference in grain Cd accumulation in different cultivars. The highest and lowest amounts of grain Cd belonged to Behrang and Sana (durum cultivars), respectively. However, the concentration of Cd in plant organs in the control samples was not detectable. Additionally, durum wheat behavior changed at the higher level of soil Cd and in contrast to previous efforts, bread wheat cultivars surprisingly accumulated more Cd in the grain and other parts of the plant than durum cultivars at levels of 20 mg kg-1. As a result, Cd accumulation in wheat can be different among cultivars due to their physiological characteristics, regardless of whether they are durum or bread.

In the study, an adsorptive removal strategy as a straightforward and fast procedure was developed to remove four aflatoxins, including aflatoxin B1 (AF-B1), aflatoxin B2 (AF-B2), aflatoxin G1 (AF-G1), and aflatoxin G2 (AF-G2). A simple and green sorbent consisting of two components (activated nanobentonite and Fe₃O₄ nanoparticles) was synthesized based on three steps using acidic treatment, ultrasonic procedure, and chemical precipitation method. The sorbent was characterized by several techniques such as FTIR, FESEM, TEM, XRD, and VSM to determine the sorbent structure and morphology. An experimental design based on a central composite design was utilized to optimize factors in the removal of AFs. The optimum values of the factors (pH, sorbent amount, shaking rate) were 6.8, 0.076 g, and 160 rpm, respectively. Three models, including pseudo-first-order, pseudo-second-order, and intra-particle diffusion models, were used to investigate the kinetics of the removal process. The removal of AFs using magnetic nanobentonite was fitted with the pseudo-second-order model better than other models with an equilibrium time lower than 30 min. The thermodynamic data show that the adsorption of AFs on the sorbent is a spontaneous and feasible process due to negative values of the Gibbs-free energy change (ΔG) at different temperatures. Two models (Langmuir and Freundlich models) were chosen to study the isotherm of the removal procedure, indicating that the Freundlich model describes the results better than the Langmuir model. The maximum adsorption capacity of the sorbent for removing AF-B1, AF-B2, AF-G1, and AF-G2 is 357.14, 400.0, 370.37, and 400.0 mg g⁻¹, respectively. The sorbent reusability was also evaluated to study the sorbent’s ability for the removal of AFs, indicating that the sorbent was used for 5 cycles without a significant reduction in the ability to remove AFs.

Numerous applications of silver nanoparticles (AgNPs), as well as the toxic effects of these particles on soil organisms and microorganisms, raise the question of how reasonable the entry of these nanoparticles into the environment is. Studying the behavior of these nanoparticles with soil organisms and also their effect on soil microorganisms may be the first step to finding out the answer. Structural and form differences in these nanoparticles for use in different conditions can change their behavior. The surface of these nanoparticles is covered with diverse coatings with differing surface charges affecting their fate in soil environments. Naturally, studying this aspect is essential to better understand how these particles impact the environment. In the present study, urease and dehydrogenase enzymes were used as soil health indicators to evaluate the effect of AgNPs and silver nitrate (AgNO₃). In order to investigate the effect of surface charge, concentration, and exposure time, three concentration levels (5, 25, 125 mg/kg soil), three different types of charged coatings (citrate (Cit), polyvinylpyrrolidone (PVP) and polyethyleneimine (PEI)) were added to the soil as a treatment and the activities of dehydrogenase (as an indicator of overall microbial activity) and urease (indicator of nitrogen cycle) were measured at three times (1 h, 1 day and 90 days) after soil contamination. The results showed that with increasing the concentration of AgNO₃ and AgNPs, the amount of dehydrogenase and urease activity decreased significantly. In the case of urease enzyme, nanoparticles with PEI coating (positive charge) had the greatest effect on reducing activity. In the case of dehydrogenase the opposite was true, and nanoparticles with Cit coating (negative charged) showed a greater inhibitory effect. With increasing incubation time, the amount of enzymatic activity of both types of enzymes showed less decrease, so that the greatest decrease in activity was in the first hour, then in the first day, and finally in 90 days. By comparing silver nitrate and nanoparticles it was found that the effect of AgNPs on enzymatic activity was greater than silver nitrate.

In this research, the potential application of phosphate containing zinc-aluminum-layered double hydroxide (Zn-Al-P-LDH) to enhance the availability of P and Zn compared to triple superphosphate (TSP) in a calcareous soil was investigated. First, soil availability of P and Zn at two P levels (18 and 45 mg kg^–1) of Zn-Al-P-LDH and TSP were compared in a 70-day incubation procedure. Second, a pot experiment was performed to study the effect of these treatments on growth and on P and Zn uptake by maize. Incubation experiment showed that, in contrast to the TSP, addition of both P levels of LDH increased P availability during the incubation period. Furthermore, the soil-available Zn in LDH was significantly enhanced compared to TSP and control treatments. This observation suggested that ion exchange accompanied by partial dissolution mechanism possibility happened for studied LDH. However, the values of shoot dry weight and leaves P uptake were significantly higher for LDH than TSP treatment just at 18 mg P kg^-1 level probably due to its effect on adequate Zn supply along with P. Therefore, Zn-Al-P-LDH might be a candidate as dual-purpose fertilizer if its limitations in terms of high Zn content to be overcome.

It has been proposed that glutathione can relieve the effects of Fe deficiency. This study tested the effects of glutathione foliar treatments to prevent Fe chlorosis, using as positive controls soil and foliar Fe fertilisation.Medicago scutellataplants were grown in soil (5.7% CaCO₃) supplemented or not with 4 and 8% CaCO₃. Two Fe(III)‐EDDHA soil treatments (5 and 10 mg Fe kg⁻¹), and three foliar treatments (three applications each of 2.14 mM Fe(III)‐EDDHA, 1 mM glutathione, and the previous two combined) were applied. Measurements include leaf chlorophyll and Fe concentrations, biomass, leaf enzymatic and non‐enzymatic antioxidant systems and carboxylates. The addition of CaCO₃caused typical Fe deficiency symptoms, including changes in chlorophyll, Fe, antioxidant systems and carboxylates, which were prevented by soil and foliar Fe fertilisation. The foliar treatment with glutathione also led to higher chlorophyll, leaf extractable Fe and root Fe, as well as decreases in some antioxidant systems, whereas leaf Fe concentrations decreased. The combined foliar application of glutathione and Fe was even more efficient in preventing chlorosis. Including glutathione in foliar fertilisation programs should be considered as an option for Fe chlorosis prevention, especially when relatively large leaf total Fe concentrations occur in the so called chlorosis paradox.

Understanding the potential of clinoptilolite (CLI) for adsorption of NH₄⁺ and K⁺, providing appropriate fertilizer formula, and evaluation of the produced zeolitic nutrient sources (ZNSs) to meet the plant need are the main objectives of this study. Three ZNSs (NH₄⁺-saturated, K⁺-saturated and dual-purpose NH₄⁺-K⁺ saturated clinoptilolite) were produced, assessed, and compared with commercial N and K fertilizers (CFs) on corn growth in greenhouse. The results indicated that CLI can potentially adsorb both NH₄⁺ and K⁺ to maximum values of 25.00 mg-NH₄⁺ g⁻¹ and 47.61 mg-K g⁻¹, respectively, and chemisorptions mainly followed the process of adsorption. Saturation of zeolite by NH₄⁺ and K⁺ occurred after 10 and 15 d which lead to ZNSs with 2% and 5% of N and K, respectively. NH₄⁺-K⁺ saturated clinoptilolite contained 1% N and 1% K. The greenhouse experiment showed no significant difference between ZNSs and CFs on plant growth. However, the application of both N and K in the form of zeolitic sources significantly increased the uptake of N by the plant. The highest uptake of K (2.05 g pot⁻¹) occurred in plants supplied with both natural zeolite and CFs. The present results may benefit the future utilization of ZNSs in environmental friendly farming practices.