Cadmium (Cd) contamination in soil threatens global food production and human health. This study investigated zinc (Zn) addition as a potential strategy to mitigate Cd stress using two barley genotypes, Dong-17 (Cd-sensitive) and WSBZ (Cd-tolerant). Hydroponically grown seedlings were treated with different Cd (0, 1.0, 10 mu M) and Zn (0, 5, 50 mu M) levels. Results showed that Zn addition effectively alleviated Cd induced growth inhibition, improving SPAD values, photosynthetic parameters, fluorescence efficiency (Fv/Fm), and biomass. Zn reduced Cd contents in roots and shoots, inhibited Cd translocation, and ameliorated Cd induced ultrastructural damage to organelles. Transcriptomic analysis revealed distinct gene expression patterns between genotypes, with WSBZ showing enhanced expression of metal transporters, antioxidant defense, and stress signaling genes. Significantly, cell wall related pathways were upregulated in WSBZ, particularly lignin biosynthesis genes (PAL, C4H, 4CL, COMT, CAD/SAD), suggesting cell wall reinforcement as a key Cd tolerance mechanism. Zn induced upregulation of ZIP family transporters and downregulation of Cd transporters (HvHMA) aligned with reduced Cd accumulation. These findings provide comprehensive insights into molecular mechanisms of Zn mediated alleviation of Cd toxicity in barley, supporting improved agronomic practices for Cd contaminated soils.

Soil cadmium (Cd) contamination threatens plant growth and agricultural productivity. Hibiscus syriacus L., valued for its ornamental, edible, and medicinal properties, is widely cultivated in Cd-contaminated areas of southern China.This study aimed to evaluate the effectiveness of nano-zinc oxide (nZnO) in alleviating Cd toxicity in H. syriacus, examining plant phenotypes, physiological and biochemical responses, root ultrastructure, and the accumulation and distribution of Cd and Zn within the soil-H. syriacus system. Pot experiments included Cd treatment (100 mg/kg) and combined soil or foliar applications of nZnO (50 and 100 mg/L), with plants harvested after 45 days. Compared to Cd treatment alone, the combined application of nZnO significantly increased biomass in roots, stems, and leaves, improved photosynthetic performance, osmotic regulation, and antioxidant levels, and mitigated root cell damage; Cd concentrated mainly in roots, and nZnO reduced root Cd levels by 0.24 %-9.06 %. SEM-EDS observations revealed that Cd predominantly accumulated in the root epidermis and cortex, with Cd stress leading to increased levels and localized aggregation of Cd in the xylem. By contrast, nZnO treatment alleviated this disruption. Leaf application of 50 mg/L nZnO showed the best results. These findings highlight nZnO as a promising nano fertilizer for alleviating Cd stress in plants.

Zinc (Zn), an essential nutrient element, exhibits hormesis in plants-beneficial at low doses but toxic at high concentrations. To understand the molecular mechanisms underlying this hormetic response with low-dose stimulation and high-dose inhibition in wheat, we conducted transcriptomic analysis under different Zn treatments. Low Zn concentration (50 mu M) promoted plant growth by maintaining chlorophyll content, enhancing MAPK signaling, phytohormone signaling, glutathione metabolism, nitrogen metabolism, and cell wall polysaccharide biosynthesis. High Zn concentration (500 mu M) induced ultrastructural damage and suppressed photosynthesis, chlorophyll metabolism, and secondary metabolisms, while upregulating glutathione metabolism. Molecular docking revealed that hydrogen bonds between Zn and antioxidant enzymes facilitated reactive oxygen species scavenging. Notably, exogenous glutathione (GSH) application enhanced wheat tolerance to Zn stress by strengthening the antioxidant defense system and improving photosynthetic capacity. Our findings elucidate the underlying mechanisms of Zn hormesis in wheat and demonstrate the application potential of glutathione in mitigating Zn toxicity, providing strategies for managing Zn-contaminated soils.

Microbially Induced Magnesium Carbonate Precipitation (MIMP) technology provides an innovative method for solidifying and stabilizing heavy metal-contaminated soils. However, the mechanical strength and microstructure of the soil following remediation require further investigation. This study evaluates the mechanical properties of zinc-contaminated soil solidified using MIMP technology under varying zinc ion concentrations, cementing solution concentrations, and curing times. Unconfined compressive strength tests, carbonate production tests, and microscopic analyses are employed to assess microstructural changes. The results indicate that MIMP enhances the unconfined compressive strength of red clay, with significantly higher strength observed in samples without zinc contamination than those with zinc contamination. The maximum unconfined compressive strength is achieved at a cementing solution concentration of 1.25 mol/L and a curing time of 15 days, conditions under which the production of magnesium carbonate also peaks. As the zinc ion concentration increases, the unconfined compressive strength of the samples gradually decrease, accompanied by a reduction in magnesium carbonate production. With longer curing times, the unconfined compressive strength increases while the amount of magnesium carbonate rises and stabilizes. Microscopic analysis reveals that MIMP treatment fills internal pores, reducing their number and enhancing the bonding strength between soil particles. The primary mineral composition consists predominantly of hydromagnesite and magnesium carbonate.

Phytoremediation is a promising approach grounded in green and sustainable development principles for decontaminating water and soil. Among the studied duckweed species (Spirodela polyrhiza, Wolffia arrhizal, and Lemna minor), S. polyrhiza exhibited the highest zinc removal efficiency of 88.50% by day 7, followed by L. minor and W. arrhiza with removal efficiency of 78.69 and 38.59%, respectively. This study investigated the effects of environmental factors, including initial zinc ion concentration (50, 100, 150, 200, and 250 mg/L), solution pH (pH 5, 6, 7, and 8), and macrophytes mass (5, 10, 15, 20, and 25 g) on the phytoremediation of the zinc ion from synthetic wastewater by S. polyrhiza. The process effectively treated 500 mL of synthetic wastewater containing 100 ppm zinc ion and the process could be enhanced to achieve the removal efficiency of 90% by adjusting the solution pH to slightly acidic (pH 5) and increasing the mass of duckweed to its saturation point (20 g). Excessive zinc intake by duckweed led to chlorophyll reduction, negatively impacting the duckweed growth rate. Scanning electron microscopy (SEM) analysis revealed that the duckweed fronds' surface became uneven after the treatment, with the irregular small particles attached due to cellular damage. The energy dispersive X-ray (EDX) analysis confirmed the successful uptake and accumulation of zinc in the duckweed cells from the synthetic wastewater. In conclusion, duckweed-based phytoremediation demonstrates significant potential for removing zinc ion from wastewater, at low and moderate concentrations.

Nickel (Ni) is a trace element that is toxic to plants and consequently results in toxicity symptoms and hazardous fitness problems in human beings through food chains. Nanoparticles (NPs) are being used in new ways to directly help plants handle Ni stress and act as nano-fertilizers. The purpose of the current study was to establish the use of biogenically produced zinc oxide nanoparticles (ZnONPs) to reduce Ni-induced toxic effect on the growth and development of watermelon (Citrullus lanatus). Watermelon seeds were sown in pot filled with five kg of soil and placed in a greenhouse. The watermelon plants were treated with Ni stress (70 mg/kg soil) at 20 DAS (days after sowing), and the treatment was applied directly into the soil. The supply of ZnONPs (100 mg/L) as foliar spray was given at 30 DAS and 38 DAS, and the sampling was performed at 55-60 DAS for biochemical and physiological analysis. The results showed that watermelon plants that were exposed to Ni had oxidative damage, which was shown by more electrolyte leakage, hydrogen peroxide, lipid peroxidation, pigment and osmolyte loss, and a loss of ultrastructural integrity in the chloroplasts. However, watermelon plants supplemented with ZnONPs under the Ni toxicity revealed significantly increased plant fresh weight (53.18%), plant dry weight (51.25%), and root length (32.14%). Moreover, the ZnONPs supplement has beneficial impacts on photosynthesis attributes, SPAD value (21.93%), and chloroplast structure observed by transmission electron microscopy (TEM) under Ni stress. Application of ZnONPs also substantially reduced the oxidative stress by lowering the levels of superoxide radical (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:{\text{O}}_{2}{-\cdot\:}$$\end{document}; 22.68%), hydrogen peroxide (H2O2; 21.18%), malondialdehyde (MDA; 21.34%), and electrolyte leakage (EL; 34.613%). The results showed that ZnONPs enhanced enzymatic activities of superoxide dismutase (SOD; 39.95%), peroxidase (POD; 19.95%), catalase (CAT; 32.85%), ascorbate peroxidase (APX; 25%) that metabolize reactive oxygen species (ROS); these increases correlated with the changes observed in the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:{\text{O}}_{2}{-\cdot\:}$$\end{document}, H2O2 and MDA after ZnONPs application. Application of ZnONPs increased the transcriptional levels of antioxidant defense genes as compared to the Ni plants alone. In conclusion, spraying ZnONPs on foliage has high effectiveness in increasing biomass, photosynthesis, protein and antioxidant enzymes, mineral nutrient concentrations, and lowering Ni concentrations in watermelon. The results indicate biogenically produced ZnONPs can be a promising technique for the remediation of Ni-contaminated soils.

Drought and soil salinization significantly constrain agricultural productivity, driving the need for molecular breeding strategies to enhance stress resistance. Zinc finger proteins play a critical role in plant response to abiotic stress. In this study, a gene encoding a C2H2-type zinc finger protein (AfZFP5) was cloned from Amorpha fruticosa, a species known for its strong adaptability. qRT-PCR analysis revealed that AfZFP5 expression is regulated by sorbitol, H2O2, NaCl, and NaHCO3. And all four treatments can cause upregulation of AFZFP5 expression in the roots or leaves of Amorpha fruticosa within 48 h. Transgenic tobacco lines overexpressing AfZFP5 demonstrated enhanced tolerance to drought and salt-alkali stress at germination, seedling, and vegetative stages. Compared to wild-type plants, transgenic lines exhibited significantly higher germination rates, root lengths, and fresh weights when treated with sorbitol, NaCl, and NaHCO3. Under natural drought and salt-alkali stress conditions, transgenic plants showed elevated activities of superoxide dismutase (SOD) and peroxidase (POD), and upregulated expression of oxidative stress-related kinase genes (NtSOD, NtPOD) during the vegetative stage. Additionally, transgenic tobacco displayed lower malondialdehyde (MDA) content and reduced staining levels with 3,3 ' diaminobenzidine (DAB) and Nitro blue tetrazolium (NBT), indicating enhanced reactive oxygen species (ROS) scavenging capacity by AfZFP5 upon salt-alkali stress. Under simulated drought with PEG6000 and salt-alkali stress, chlorophyll fluorescence intensity and Fv/Fm values in transgenic tobacco were significantly higher than in wild-type plants during the vegetative stage, suggesting that AfZFP5 mitigates stress-induced damage to the photosynthetic system. This study highlights the role of AfZFP5 in conferring drought and salt-alkali stress tolerance, providing genetic resources and a theoretical foundation for breeding stress-resistance crops.

Zinc, an important micronutrient, offers a crucial role in plant growth and development. However, its deficiency can significantly impair plant growth by disrupting essential physiological processes, leading to stunted growth and reduced reproductive capacity. Agronomic Zn biofortification offers the dual benefits of enhancing yield and improving grain Zn concentration. In this study, we evaluated various doses of zinc sulfate (ZnSO4; 0, 100, 200, 300, 400, and 500 mM) for their effectiveness in improving the performance of rice cultivars (Basmati-198 and PK-386) in alkaline Zn-deficient soil. Our results showed that ZnSO4 application significantly enhanced seedlings performance where 400 mM dose outperformed other treatments. Notably, ZnSO4 application at 400 mM increased seedling Zn accumulation by 152.40% and 125.96% in Basmati-198 and PK-386, respectively, over control. This dose also improved root dry weight by 74.52%, net photosynthesis by 41%, the activities of catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and superoxide dismutase (SOD) by 79.88%, 23.80%, 58.77% and 75.72%, respectively, in Basmati-198 compared with PK-386. Moreover, ZnSO4 application (at 400 mM) alleviated oxidative damage by reducing malondialdehyde (58.12% and 56.63%), hydrogen peroxide (60.13% and 58.15%), and electrolyte leakage (31.39% and 29.06%) in Basmati-198 and PK-386, respectively, compared with the control without ZnSO4 supplementation. This study also demonstrated that ZnSO4 application increased the expression of bZIP genes, including OsbZIP08, OsbZIP16, OsbZIP21, and OsbZIP60, which are highly responsive to Zn deficiency in rice. Notably, the expression levels of these genes were highest following ZnSO4 application at 400 mM, resulting in a 7.1- and eightfold increase in OsbZIP21 expression, a 6.2- and 7.4-fold increase in OsbZIP16 expression, a 5- and 6.3-fold increase in OsbZIP08 expression, and a 4.5- and fivefold increase in OsbZIP60 expression in PK-386 and Basmati-198, respectively, compared to the control. The highest fold-change expression was observed for OsbZIP21 gene in Basmati-198, followed by OsbZIP16 and OsbZIP08, while OsbZIP60 exhibited the lowest fold change in the same cultivar. These findings contribute to ongoing efforts to enhance plant nutrient uptake efficiency and deepen our understanding of the mechanisms governing Zn assimilation in plants.

Cadmium (Cd) is a widespread and strongly toxic environmental pollutant. In this study, the interaction between Cd and essential nutritional metals, such as iron (Fe) and zinc (Zn), was investigated in banana plants (Musa spp. cultivar Grand Nain), cultured in vitro, using Fourier-transform infrared (FT-IR) and physiological analysis. Plantlets were treated in vitro with Fe and Zn (200 and 500 mg/L) under 500 mg/L Cd exposure. The results showed that Cd toxicity increased Cd uptake and raised % of damage. However, Fe and Zn addition ameliorated the negative impact of Cd stress by reducing Cd and enhancing Fe, Zn, P, and K contents. The FT-IR analysis showed alterations within the bands correlated to the foremost macromolecules in plants under Cd stress and its interactions with Fe or Zn. The peaks of some functional groups at 3381.7 cm-1 for carbohydrates, proteins, alcohols, and phenolic compounds, 2922.02 cm-1 for lipids, 1643.97 cm-1 for amide I, 1517.46 cm-1 for amide II, 1057.63 cm-1 for cellulose and hemicellulose, and 616.94 cm-1 for aromatic compounds were negatively shifted by Cd stress. However, Fe and Zn regulated transmittance and intensity of these bands, showing improved tolerance to Cd. Moreover, Fe and Zn modulated the total antioxidants and enzymatic antioxidant activities for catalase and ascorbate peroxidase. The study concluded that the nutrition with Fe and Zn enhanced banana tolerance against Cd toxicity. It also highlighted the powerful role of FT-IR in understanding the mechanisms involved in minimizing Cd toxicity in banana shoots under Fe and Zn.

Zinc-ion capacitors (ZICs) are viewed as a promising energy storage solution for portable electronics and biocompatible devices. Nevertheless, current ZICs technology faces challenges such as restricted specific capacitance, suboptimal cycling performance, and ongoing validation efforts regarding their biocompatibility. Herein, hierarchical porous carbon materials were prepared through a two-step carbonization-activation method using kapok fiber biomass as the precursor. The kapok fibers-based cathodes contain abundant micropores and mesopores, which provide abundant active sites for Zn2+ storage and optimize reaction kinetics. The ZICs demonstrate an ultra-high cycling life exceeding 240,000 cycles. Meanwhile, theoretical calculations verify that large micropores exhibit a reduced diffusion energy barrier for [Zn(H2O)6]2+, which accelerates [Zn(H2O)6]2+ adsorption/desorption and increases the available reversible capacitance. Furthermore, the ZICs exhibit excellent biodegradability in soil, simulated human body fluids and real seawater, and low cytotoxicity to human cells and minimal tissue damage in animal. This research presents a potential pathway for the advancement and verification of biocompatible ZICs, thereby contributing to their prospective practical utilization in biomedical and environmental field.