Zinc Availability Research Articles

Spray-Drying Microencapsulation of Bacillus megaterium in PVA/Cationic Starch/Zinc Oxide for Promoting Growth and Zinc Availability in Soybean Plants

Spray-Drying Microencapsulation of <i>Bacillus megaterium</i> in PVA/Cationic Starch/Zinc Oxide for Promoting Growth and Zinc Availability in Soybean Plants

The efflux system CdfX exports zinc that cannot be transported by ZntA in Cupriavidus metallidurans.

Cupriavidus metallidurans is able to survive exposure to high concentrations of transition metals, but is also able to grow under metal starvation conditions. A prerequisite of cellular zinc homeostasis is a flow equilibrium combining zinc uptake and efflux processes. The mutant strain ∆e4 of the parental plasmid-free strain AE104 with a deletion of all four chromosomally encoded genes of previously known efflux systems ZntA, CadA, DmeF, and FieF was still able to efflux zinc in a pulse-chase experiment, indicating the existence of a fifth efflux system. The gene cdfX, encoding a protein of the cation diffusion facilitator (CDF) family, is located in proximity to the cadA gene, encoding a P-type ATPase. Deletion of cdfX in the ∆e4 mutant resulted in a further decrease in zinc resistance. Pulse-chase experiments with radioactive 65Zn(II) and stable-isotope-enriched 67Zn(II) provided evidence that CdfX was responsible for the residual zinc efflux activity of the mutant strain ∆e4. Reporter gene fusions with cdfX-lacZ indicated that the MerR-type regulator ZntR, the main regulator of zntA expression, was responsible for zinc- and cadmium-dependent upregulation of cdfX expression, especially in mutant cells lacking one or both of the previously characterized efflux systems, ZntA and CadA. Expression of zntR also proved to be controlled by ZntR itself as well as by zinc and cadmium availability. These data indicate that the cdfX-cadA region provides C. metallidurans with a backup system for the zinc-cadmium-exporting P-type ATPase ZntA, with CdfX exporting zinc and CadA cadmium.IMPORTANCEBacteria have evolved the ability to supply the important trace element zinc to zinc-dependent proteins, despite external zinc concentrations varying over a wide range. Zinc homeostasis can be understood as adaptive layering of homeostatic systems, allowing coverage from extreme starvation to extreme resistance. Central to zinc homeostasis is a flow equilibrium of zinc comprising uptake and efflux reactions, which adjusts the cytoplasmic zinc content. This report describes what happens when an imbalance in zinc and cadmium concentrations impairs the central inner-membrane zinc efflux system for zinc by competitive inhibition for this exporter. The problem is solved by activation of Cd-exporting CadA or Zn-exporting CdfX as additional efflux systems.

Study on Nano-Zn, Inorganic, and Organic Nutrient Management Practices and Their Impact on Nutrient Availability in Kharif Maize (Zea mays L.)

A study was conducted to assess the impact of Nano-Zn, inorganic, and organic nutrient management practices on the physico-chemical properties and nutrient availability in Kharif maize (Zea mays L.) grown during 2022 and 2023 at Chandra Shekhar Azad University of Agriculture &amp; Technology, Kanpur. The experiment followed a split-plot design, with organic manures (Control, FYM at 10 t/ha, and Vermicompost at 5 t/ha) as the main plot treatments and various nutrient management strategies (Control, 75% RDF, 75% RDF + ZnSO4 at 25 kg/ha, 75% RDF + Nano-Zn at 10 ml/litre, 100% RDF, 100% RDF + ZnSO4, and 100% RDF + Nano-Zn) as the subplot treatments. Results showed that combining 100% RDF with Nano-Zn and ZnSO4 significantly enhanced soil nutrient availability and improved physico-chemical properties compared to control treatments. The organic carbon content was highest in the 100% RDF + Nano-Zn treatment (0.492%), suggesting an increase in soil organic matter. Nitrogen availability was significantly higher in this treatment, with a pooled value of 151.167 kg/ha, compared to 143.443 kg/ha in the control. Phosphorus availability also increased in the 100% RDF + Nano-Zn treatment (16.337 kg/ha), indicating better phosphorus mobilization. Potassium availability was enhanced, with the highest recorded value (216.39 kg/ha) in the 100% RDF + Nano-Zn treatment, while the control treatment had 213.597 kg/ha. Zinc availability was markedly improved, with the 100% RDF + Nano-Zn treatment reaching 0.853 mg/kg, compared to 0.79 mg/kg in the control. This study demonstrated that integrating Nano-Zn and ZnSO4 with inorganic fertilizers significantly improved soil fertility, nutrient availability, and potentially enhanced crop performance in Kharif maize. These findings indicate that combining inorganic and nano-fertilizers could be an effective nutrient management strategy, contributing to sustainable agricultural practices and improved productivity in maize cultivation, alongside better soil health.

Effects of ZinT-Mediated Zinc Sequestration on Metallo-β-Lactamase Function in Escherichia coli

β-lactams are the most prescribed antibiotic class, but their clinical utility is threatened by the production of metallo-β-lactamase (MBL) enzymes by resistant bacteria. MBLs such as NDM-1 employ zinc ions as cofactors, allowing them to degrade β-lactams. The zinc chaperone ZinT transports zinc into the cytoplasm for intracellular functions, potentially decreasing the availability of zinc in the periplasm for MBLs. We hypothesize that when zinc is limited, ZinT could impair NDM-1 activity and make bacteria more susceptible to β-lactams. To determine whether ZinT and NDM-1 compete for periplasmic zinc, bacterial growth and NDM-1 activity were tested in zinc-poor M9 minimal media for NDM-1-producing Escherichia coli strains with different levels of zinT expression. In addition to wild-type and ΔzinT knockout strains, a recombinant zinT-containing plasmid was transformed into ΔzinT knockout cells to produce a complementation strain with increased zinT expression. Growth assays were conducted in M9 with various concentrations of the β-lactam antibiotic, meropenem. Under these conditions, the ΔzinT strain grew in significantly higher meropenem concentrations than the other strains tested. NDM-1 activity assays revealed that the ΔzinT strain hydrolyzed meropenem notably faster than wild-type cells, whereas the complementation strain showed almost no hydrolysis. This suggests that the increased ZinT production in the complementation strain effectively sequestered zinc from NDM-1. These differences in meropenem hydrolysis and bacterial growth were absent in zinc-sufficient Cation-Adjusted Mueller-Hinton Broth, providing evidence that ZinT and NDM-1 compete for periplasmic zinc under nutrient deficiency. Overall, our results elucidate the effects of competing zinc requirements under zinc-deficient conditions resembling the host environment during a bacterial infection. In these zinc-deficient environments, ZinT can deprive NDM-1 of zinc, causing impaired enzymatic activity and bacterial survival. By better understanding how MBLs function under physiological conditions, future investigations can more reliably explore countermeasures to the growing threat of antibiotic resistance.

Significant effect of salinity on zinc adsorption on tropical coastal and floodplain soils

AbstractRising sea levels due to climate change are causing increased salinisation of low‐lying coastal and floodplain soils, and the impact of this process on the bioavailability of plant nutrients needs to be understood as mitigation strategies are adapted. Zinc (Zn) is an element of particular importance due to its function as a micronutrient for plants including rice and other staple foods. In the current study, our aim was to investigate the effects of salinisation on zinc adsorption onto soils representing at‐risk coastal and floodplain environments, addressing in particular our knowledge gap concerning the roles that solution chemistry and soil composition play. To this end, we conducted batch adsorption experiments in the laboratory and ran geochemical models in saline solutions up to 0.7 mol L−1 ion strength incorporating both (i) a multi surface model (MSM) for surface reactions containing three phases, that is iron hydroxides, organic matter and phyllosilicate clays, and (ii) aqueous‐phase complexation to dissolved organic and inorganic ligands. Surface reactions were modelled using the diffuse double layer model, the NICA–Donnan model and an ion exchange model using the Gaines–Thomas convention. We combined the experimentally determined mass composition of surface phases with generic modelling parameters taken from the literature. We first show that increasing salinity enhances the formation of aqueous Zn‐chloride complexes in the presence of dissolved organic matter and bicarbonate, thereby decreasing the availability of free Zn2+ and supressing the partitioning of zinc to the adsorbed phase. We demonstrate using batch adsorption experiments with a calcareous hydraquent and a tropaquept, that salinity decreases zinc adsorption strongly in the pH range between 3 and 6. Satisfactory agreement between experiments and model calculations was achieved with root‐mean‐square errors ranging for different salinities between 2.88% and 2.92% for the hydraquent and between 4.59% and 2.74% for the tropaquept soil. Model predictions of adsorption were slightly inferior at low salinity for the hydraquent soil and at high salinity for the tropaquept soil, pointing possibly to an incomplete geochemical model or to a need to parametrise surface adsorption models at higher ionic strengths. Present surface models have been largely parametrised at lower ionic strength. We lastly apply the MSM to examine zinc adsorption in five endoaquepts soils, representing soil series from Bangladesh. We show that increasing salinity decreases zinc adsorption to the soil organic matter and the clay fractions. We conclude from our findings that increased soil salinity due to rising sea levels and climate change will have a significant impact on zinc cycling and possibly other micronutrients in areas where coastal soils and floodplain soils overlap, such as deltas and estuaries. In particular, we predict a decrease in zinc adsorption in acidic to neutral soils. The availability of zinc for biouptake through the roots of crop plants including rice will be significantly disturbed following salinisation, most likely affecting crop production. Our study demonstrates the potential that geochemical modelling combined with experimental data has to improve our capability to assess the effects of salinity due to rising seawater levels in vulnerable regions of the world.

Zinc in ammoniated phosphate fertilizers: Solid‐phase speciation, solubility, and use of barrier coatings to enhance zinc availability

AbstractZinc (Zn) is the micronutrient commonly found deficient in agricultural soils worldwide, limiting crop yield and reducing food quality. Zinc‐enriched fertilizers have been successfully used to tackle crop Zn deficiency. However, Zn solubility is reduced after addition to phosphate fertilizers due to the formation of sparingly soluble precipitates, decreasing Zn availability to crops. We hypothesized that the availability of Zn in the fertilizer to plants is related to its speciation in the fertilizer. We evaluated a range of ammonium phosphate fertilizers using X‐ray absorption near‐edge structure and assessed the water‐solubility of Zn in the formulations. Four Zn species were identified in these fertilizers, with zinc ammonium phosphate the most abundant one. The speciation of Zn in the fertilizer had little relationship with the water solubility of Zn in the final product. Zinc solubility was driven by fertilizer pH, with lower pH resulting in higher solubility. We concluded that added Zn reacts with the fertilizer matrix to form mainly zinc (ammonium) phosphates, and when the fertilizer is dissolved in water, hopeite controls the solubility. Based on these findings, we tested whether a barrier coating between the P granule and the Zn compound could prevent reaction between Zn and P and thus enhance Zn availability. Indeed, higher Zn uptake was observed in an isotopically labeled fertilizer growth trial when a barrier coating physically separated Zn and P in the fertilizer. In summary, Zn availability to crops can be maximized by decreasing fertilizer pH and separating P and Zn in the granule.

Zinc Supplementation Reduces the Formation of Neutrophil Extracellular Traps by Decreasing the Expression of Peptidyl Arginine Deiminase 4.

Neutrophils play a decisive role during the immediate defense against infections. However, as observed during rheumatoid arthritis, activated neutrophils can also cause tissue damage. Previous studies indicate that zinc supplementation may alter certain neutrophil functions. However, precise underlying mechanisms and possible effects of zinc deficiency remain incompletely understood. The objective of this study is to investigate the effects of changes in zinc status on formation of neutrophil extracellular traps (NETs) and other fundamental neutrophil functions. Interleukin (IL)-17 and tumor necrosis factor (TNF)-α are used to simulate the inflammatory environment observed in autoimmune diseases. The study analyzes the impact of the zinc status on NETs release, using a fluorescence plate reader, and on the expression of peptidylarginine deiminase 4 (PAD4), S100A8/A9, and certain cytokines by PCR and western blot. These results show that zinc supplementation significantly reduces NETs formation and downregulates PAD4 protein expression. Zinc supplementation results in increased protein expression of interleukin-1 receptor antagonist (IL-1RA) and IL-8 in stimulated cells. The results suggest that changes in extracellular zinc availability may influence the functions of neutrophils. Therefore, maintaining an appropriate zinc level is advisable for preserving innate immunity and to prevent hyper-activation of neutrophils.

Impact of Zinc and Silica Solubilizing Bacterial Consortia on Soil Nutrient Availability and Direct Sown Paddy

Effect of zinc and silica solubilizing bacteria and their consortia on paddy was studied under field conditions at Agricultural Research Station, Janagamaheswarapuram, Andhra Pradesh. Thirteen treatments were assessed for availability of nutrients viz., Nitrogen, Phosphorus, Potassium, Zinc and Silica in soil and concentration of Nitrogen, Phosphorus and Potassium in plant at 45, 90 and 120 days after sowing (DAS).Significantly highest nitrogen (198.9, 262.3 and 240.2 kg ha-1), available phosphorus (36.7, 64.7 and 40.6 kg ha-1), potassium (221.4, 349.6 and 263.5 kg ha-1), zinc (0.86, 1.14 and 0.98 ppm) and silica (66.8, 98.9 and 84.8 ppm) were recorded in T13 (RDF + ZnKJJ-4 &amp; ZnPGG-1 + SiKPP-1 &amp; SiPYY-3) at 45, 90 and 120DAS, respectively. In the plant, nitrogen (0.89, 1.10 and 0.98 %), phosphorus (0.46, 0.67 and 0.58 %) and potassium (1.87, 2.29 and 1.98 %) were significantly highest at 45, 90 and 120DAS, respectively, in T13. There was increase in the available nutrient content upto90 DAS which then decreased at 120DAS. It is inferred that consortia of two zinc solubilizing and two silica solubilizing microorganisms (T13) is useful for increased availability of Nitrogen, Phosphorus, Potassium, Zinc and Silica in soil and increased uptake of NPK by rice plant, which in turn reduce exogenous chemical fertilizers.

The metal-binding GTPases CobW2 and CobW3 are at the crossroads of zinc and cobalt homeostasis in Cupriavidus metallidurans.

The metal-resistant beta-proteobacterium Cupriavidus metallidurans is also able to survive conditions of metal starvation. We show that zinc-starved cells can substitute some of the required zinc with cobalt but not with nickel ions. The zinc importer ZupT was necessary for this process but was not essential for either zinc or cobalt import. The cellular cobalt content was also influenced by the two COG0523-family proteins, CobW2 and CobW3. Pulse-chase experiments with radioactive and isotope-enriched zinc demonstrated that both proteins interacted with ZupT to control the cellular flow-equilibrium of zinc, a central process of zinc homeostasis. Moreover, an antagonistic interplay of CobW2 and CobW3 in the presence of added cobalt caused a growth defect in mutant cells devoid of the cobalt efflux system DmeF. Full cobalt resistance also required a synergistic interaction of ZupT and DmeF. Thus, the two transporters along with CobW2 and CobW3 interact to control cobalt homeostasis in a process that depends on zinc availability. Because ZupT, CobW2, and CobW3 also direct zinc homeostasis, this process links the control of cobalt and zinc homeostasis, which subsequently protects C. metallidurans against cadmium stress and general metal starvation.IMPORTANCEIn bacterial cells, zinc ions need to be allocated to zinc-dependent proteins without disturbance of this process by other transition metal cations. Under zinc-starvation conditions, C. metallidurans floods the cell with cobalt ions, which protect the cell against cadmium toxicity, help withstand metal starvation, and provide cobalt to metal-promiscuous paralogs of essential zinc-dependent proteins. The number of cobalt ions needs to be carefully controlled to avoid a toxic cobalt overload. This is accomplished by an interplay of the zinc importer ZupT with the COG0523-family proteins, CobW3, and CobW2. At high external cobalt concentrations, this trio of proteins additionally interacts with the cobalt efflux system, DmeF, so that these four proteins form an inextricable link between zinc and cobalt homeostasis.

Effect of Zinc and Silica Solubilizing Microbial Consortia on Soil and Plant Nutrient Status in Paddy

Effect of zinc and silica solubilizing bacteria and their consortia on paddy was studied under pot culture conditions at Agricultural Research Station, Janagamaheswarapuram, Andhra Pradesh, India. Thirteen treatments were assessed for availability of nutrients viz., Nitrogen, Phosphorus, Potassium, Zinc and Silica in soil and concentration of Nitrogen, Phosphorus and Potassium in plant at 45, 90 and 120 days after sowing (DAS). Significantly highest nitrogen (189.3, 249.4 and 239.7 kg ha-1), available phosphorus (34.6, 61.8 and 38.5 kg ha-1), potassium (214.2, 347.9 and 232.1 kg ha-1), zinc (0.78, 0.99 and 0.86 ppm) and silica (60.1, 90.8 and 78.4 ppm) were recorded in T13 (RDF + ZnKJJ-4 &amp; ZnPGG-1 + SiKPP-1 &amp; SiPYY-3) at 45, 90 and 120DAS. In plant, nitrogen (0.79, 0.99 and 0.89 %), phosphorus (0.37, 0.58 and 0.49 %) and potassium (1.78, 2.18 and 1.89 %) were significantly highest in T13. There was increase in available nutrient content upto 90 DAS which then decreased at 120DAS. It is inferred that consortia of two zinc solubilizing and two silica solubilizing microorganisms (T13) is useful for increased availability of Nitrogen, Phosphorus, Potassium, Zinc and Silica in soil and increased uptake of NPK by rice plant.

Application of zinc modified biochars to enhance zinc availability, speciation and bajra growth in Zn-deficient soil

Zinc deficiency poses a serious threat to numerous crops and global human populations. Recently, soil biochar amendment has being promoted as a sustainable farming method. However, its consequence on the bioavailability of Zn in cereal crop has not been fully addressed. In the present study, 0.01% Zn-SO4 (w/w) was loaded in fruit waste, farmyard manure and coconut shell pyrolysis at 400 ℃, for 2 h to make fruit waste Zn-modified biochar (FWZn-MBC), farmyard manure Zn-modified biochar (FYZn-MBC) and coconut shell Zn-modified biochar (CSZn-MBC). Except control treatment, all the modified biochars were applied at 1, 2 and 4% doses on zinc availability, speciation, bajra growth and chemical properties in Zn-deficient soil. The obtained results showed that Zn mobility in soil was 70.04% with application of FYZn-MBC 4% as compared with other treatments. The maximum uptake of Zn in shoot and root by bajra plant was observed by 74.02% and 53% with addition of FYZn-MBC 4% as compared with control soil, due to an increase of soil organic matter. The chlorophyll SPAD values in the bajra aerial surface was increased from 30.23 to 39.24 with application FYZn-MBC 4% than control. The exchangeable fraction of Zn was increased from 7.34 to 14.71% with application of FYZn-MBC 4%. The correlation matrix results indicated that CaCO3 was positively correlated with soil pH. Soil organic matter was highly significant correlated with chlorophyll. Overall, future studies must be carried out to examine the long-term impact of FYZn-MBC 4% on Zn phytoavailbility in Zn-deficient soil.

Response of Different Level of Nitrogen and Foliar Application of Nano Zinc on Physico-chemical Properties of Soil in Wheat (Triticum aestivum. L) Var. PWB-373

A field experiment was conducted during the of 2023-24 at the Research Farm, Department of Soil Science and Agricultural Chemistry, Naini Agriculture Institute, Sam Higginbottom University of Agriculture Technology and Sciences, to investigate the Response of different levels of Nitrogen and Foliar application of nano zinc on Soil Health and Yield of Wheat (Triticum aestivum L.). We designed the experiment using a Randomized Block Design (RBD) with 10 treatments and three replications. Results indicated that the application of nano fertilizers significantly influenced various soil physico chemical properties. Bulk density was 1.27Mg m⁻³ to 1.31 Mg m⁻³ at 0-15 cm soil depth, and 1.29 to 1.32 Mg m⁻³ at 0-15 and 15-30 cm soil depth. Particle density was 2.65 to 2.67 Mg m⁻³ at 0-15 cm depth, and from 2.60 to 2.62 Mg m⁻³ at 15-30 cm depth. Pore space was 47.09% to 48.99% at 0-15 cm depth and 47.09% and 48.84% at 0-15 and 15-30 cm depth. Water holding capacity varied between 45.22% and 46.64% at 0-15 cm depth, and 45.14% and 46.89% at 15-30 cm depth. Soil pH was 6.98 to 7.04 at 0-15 cm depth and from 7.00 to 7.05 at 15-30 cm depth. Electrical conductivity (EC) was 0.13 dS m⁻¹ to 0.19 dS m⁻¹ at 0-15 cm depth, and from 0.13 dS m⁻¹ to 0.19 dS m⁻¹ at 15-30 cm depth. Organic carbon content was 0.423%-0.493% at 0-15 cm depth and 0.261% to 0.334% at 15-30 cm depth. The use of NPK and nano zinc also significantly influenced the availability of available nitrogen, phosphorus, potassium, and zinc. These findings suggest that nano fertilizers can effectively enhance soil health and wheat productivity.

Application of Zinc Modified Biochars to Enhance Zinc Availability, Speciation and Pearl Millet Growth in Zn-Deficient Soil

Application of Zinc Modified Biochars to Enhance Zinc Availability, Speciation and Pearl Millet Growth in Zn-Deficient Soil

Mandatory large-scale food fortification programmes can reduce the estimated prevalence of inadequate zinc intake by up to 50% globally

Large-scale food fortification (LSFF) can increase dietary micronutrient intake and improve micronutrient status. Here we used food balance sheet data from the Food and Agriculture Organization of the United Nations to estimate current country-specific prevalences of inadequate zinc intake. We assessed the potential effects of improving existing LSFF programmes for cereal grains or implementing new programmes in 40 countries where zinc deficiency is a potential public health problem. Accounting for LSFF programmes as currently implemented, 15% of the global population (1.13 billion individuals) is estimated to have inadequate zinc intake. In countries where zinc deficiency is a potential public health problem, the implementation of high-quality mandatory LSFF programmes that include zinc as a fortificant would substantially increase the availability of zinc in the national food supply, reducing the estimated prevalence of inadequate zinc intake by up to 50% globally. Investments in strong LSFF programmes could have a substantial impact on population zinc status.

Exploring the potential of Canavalia ensiformis for phytoremediation of B10 biodiesel-contaminated soil: insights on aromatic compound degradation and soil fertility

The widespread use of petroleum-based fuels poses a significant environmental problem due to the risks associated with accidental spills. Among the treatments available, phytoremediation is increasingly accepted as an effective and low-cost solution. This study aimed to evaluate the degradation of the aromatic fraction of biodiesel B10 and the soil fertility analysis in artificially contaminated soils treated with phytoremediation. The experimental design consisted of a 3x3 factorial, with three types of soil treatment: control, autoclaved, and planted with C. ensiformis L, and three levels of B10 biodiesel contamination: 0, 1, and 2%, to simulate spills of 30,000 and 60,000 L ha−1. The soil was analyzed at three depths: 0–10, 10–20, and 20–30 cm. The results indicated that aromatic compound degradation after phytoremediation was superior to 92,76% and 88,65% for 1% and 2% B10 soil contamination, respectively. The fuel contamination affected soil fertility, reducing the availability of phosphorus and zinc while increasing the Total Organic Carbon (TOC), pH, and the availability of manganese and iron for plants.

Effects of Returning Green Manure-Chinese Milk Vetch on the Availability and Transformation of Zinc in Purple Tidal Mud Soil under Rice Cultivation

This study aimed to investigate the impact of different levels of Chinese milk vetch (Astragalus sinicus L.) incorporation on the availability and transformation of zinc in purple tidal mud soil under rice cultivation. A two-year pot experiment was conducted, comprising seven treatments: a control group without fertilizer, a control group with Chinese milk vetch application, a control group with chemical fertilizer application, and four treatment groups with varying levels of Chinese milk vetch application following chemical fertilizer application. Results showed that Chinese milk vetch application increased the content of available zinc (DTPA-Zn) in purple tidal mud soil. Sole application of Chinese milk vetch ultimately enhanced the transfer factor of zinc in purple tidal mud soil and reduced the distribution index. However, applying Chinese milk vetch after chemical fertilizer application ultimately decreased the transfer factor of zinc and increased the distribution index. Furthermore, sole application of Chinese milk vetch facilitated the conversion of zinc in purple tidal mud soil into available forms, while applying it after chemical fertilizer application promoted the transformation of zinc into ineffective forms, with a greater conversion observed at higher levels of Chinese milk vetch application.

Biofortification of wheat in salt-affected soil through seed priming and soil application of zinc

ContextGiven the global significance of wheat production and consumption, it is imperative to achieve high yields of nutritious wheat grains. However, the inadequate availability of zinc (Zn) in salt-affected soils can aggravate salt stress, decrease wheat grain yield, and grain Zn concentration. This study compared the effectiveness of soil Zn application and seed Zn priming in increasing Zn biofortification and grain yield of Zn-biofortified wheat grown in alkaline-calcareous soil affected by salts. MethodsEighteen pots were filled with alkaline-calcareous soil containing elevated levels of soluble salts and exchangeable sodium (Na). The pots were subjected to soil Zn application (0 or 8 mg kg−1) and seed priming (control/non-, hydro-, or Zn-primed seeds) treatments, applied to a Zn-biofortified wheat (cv. Zincol-2016). Plant samples were collected at the heading and maturity stages to measure parameters related to plant growth and grain quality. FindingsSoil Zn application increased grain and straw yields across seed priming treatments by a maximum of 23 %, and seed Zn priming increased grain and straw yields across soil Zn rates by a maximum of 21 %. This yield response was accompanied by significant increases in grain potassium and Zn concentrations at maturity, as well as non-significant to significant increases in photosynthetic parameters (stomatal conductance, photosynthetic rate and transpiration rate) in flag leaves during heading. Additionally, compared to control, the combined treatment of soil Zn application and seed Zn priming decreased grain Na concentration by 14 %. Compared to control, both soil Zn application and seed Zn priming significantly increased grain Zn concentration. With the combined application treatment, the grain Zn concentration reached 27 mg kg−1, but it remained significantly below the desired level of >37 mg kg−1. Seed Zn priming decreased the phytate-to-Zn molar ratio in grains, while the treatments that received soil Zn application exhibited the lowest values of this ratio, potentially increasing Zn bioavailability to humans. ConclusionsThe findings suggest that soil Zn application is more effective in enhancing grain yield and Zn concentration, while seed Zn priming remains crucial in low-Zn and high-salt soils. Future research should optimize Zn application strategies for Zn-biofortified wheat cultivated in salt-affected fields.

Zn Check: Revolutionizing Plant Nutrition with Amino Acid-based Zinc Chelation

Zinc plays a vital role in plant growth and development, impacting essential physiological processes such as cell division, nitrogen, carbohydrate metabolism and chloroplast development. However, zinc deficiency poses a significant challenge in agriculture, particularly in crops grown on calcareous soils. Traditional zinc fertilizers, like Zn EDTA, face limitations in alkaline soils, prompting the need for innovative solutions. This study introduces an amino acid-based chelating agent, Zinc Check, synthesized to address these challenges effectively. The research demonstrates the stability and efficacy of Zinc Check across diverse soil conditions, ensuring zinc availability to plants. Through various analytical techniques and pot trials with Pak choi plants, the study confirms the effectiveness of Zinc Check in promoting plant growth and chlorophyll synthesis, surpassing the performance of conventional zinc fertilizers. Moreover, the investigation explores the pH tolerance of Zinc Check, highlighting its stability across a wide pH range. Overall, this study underscores the importance of innovative solutions like Zinc Check in addressing zinc deficiency and enhancing agricultural productivity, contributing to global food security efforts.

Low zinc availability limits the response to phosphorus fertilization in cotton

AbstractBackgroundCotton productivity is commonly limited by the imbalanced nutritional status of phosphorus (P) and zinc (Zn) in Brazil. Evaluating the effect of the P–Zn interaction on nutrient availability in soil is crucial, as this interaction promotes plant adaptations that modify the availability of these nutrients in the rhizosphere. However, the influence of root growth on the P–Zn interaction and its adsorption in rhizosphere soil remains poorly understood.AimWe tested the interaction of P and Zn rates in two classes of soil cultivated with cotton. The aim of this investigation was to evaluate the P and Zn availability and adsorption capacity by rhizosphere soils cultivated with cotton plants subjected to P and Zn rates.MethodsCotton plants were grown under greenhouse conditions in two different soils (Entisol and Oxisol), with different P and Zn rates. Phosphorus fractionation and Zn sequential extraction were assessed in rhizosphere soil, while total P and Zn concentrations were measured in the shoot and roots.ResultsSoil type significantly affected the P–Zn availabilities on rhizosphere soils. Although increased P‐rates raised P‐soil availability on bulk and rhizosphere soils, cotton growth was not increased under low soil‐Zn availability. The labile inorganic P content was influenced by P and Zn rates just in Oxisol. In both soils, the Zn‐ Zn‐exchangeable content was decreased by P rates, while Zn bound to oxides increased.ConclusionsSoil‐type effects on P–Zn interaction could have important implications for increasing cotton productivity. Increased cotton productivity by P application was only achieved with an adequate supply of Zn.

Enhancing sunflower resilience: Zinc-solubilizing bacteria mitigate cadmium uptake and translocation

&lt;p&gt;Cadmium (Cd) is a highly hazardous metal known for its easy absorption and accumulation in plants, particularly in edible vegetable oils. Sunflower (Helianthus annuus L.) holds global significance as an oil crop. This study aims to assess the potential of zinc-solubilizing bacterial strains in reducing cadmium uptake by enhancing zinc availability in sunflower plants. For this investigation, we selected twelve pre-isolated zinc-solubilizing bacterial (ZSB) strains for screening against cadmium tolerance and were evaluated for their exopolysaccharides (EPS) and siderophore production capabilities. Four strains exhibiting excellent tolerance to cadmium, EPS production, and siderophore production were subsequently inoculated into sunflower plants to determine the cadmium concentration to determine EC50 at various cadmium levels (ranging from 0 to 200 mg kg-1). Following the compatibility assessment of these strains as single and consortium inoculation, sunflower seeds were cultivated in jars containing soil with two cadmium levels (0 and 125 mg kg-1), totaling 600 g of soil. Our findings demonstrated that the application of ZSB significantly enhanced sunflower growth while simultaneously reducing cadmium uptake. Particularly noteworthy was the performance of the bacterial consortium, composed of strains ZM27 and AN31, which resulted in a remarkable 96% reduction in cadmium translocation, an 86% decrease in cadmium bioaccumulation, and a 97% reduction in overall cadmium uptake compared to the control group. Moreover, the same treatment has caused increase in root length (21.6%), shoot length (18.8%), chlorophyll contents (23.5%), Zn in shoot (30.8%), root Zn contents (13.5%), seedling vigor (49.6%) and leaf area (23.1%) of sunflower under Cd stress as compared to control. The present study concludes that zinc-solubilizing bacterial strains, in consortium ZM27+AN31 were found effective in mitigating the adverse effects of cadmium uptake in sunflower plants. These results suggest that bacterial inoculation strategies hold significant promise for reducing cadmium content in sunflower crops, thereby enhancing the safety and suitability of sunflower-derived edible oils for human consumption and safeguarding human health.&lt;/p&gt;