Application Of Zinc Oxide Nanoparticles Research Articles

Seed Priming and Coating by Nano-Scale Zinc Oxide Particles Improved Vegetative Growth, Yield and Quality of Fodder Maize (Zea mays)

Nano-fertilizers of essential plant nutrients, including micronutrients, have the potential to improve nutrient use efficiency and productivity of field crops in deficient soils. The present study reports the comparative influence of zinc oxide nanoparticles (ZnONPs) and bulk Zn salt (ZnSO4) on the growth, yield, and quality of fodder maize (Zea mays) (var. J-1006) cultivated under field conditions in the year 2019. Three levels (0, 20, and 40 mg L−1) of Zn fertilizers were used for seed priming and coating in triplicate following the randomized complete block design model. An increase in vegetative and yield parameters (number of plants, plant height, stover yield, plant biomass), acid detergent fiber (ADF%), and hemicellulose contents and shoot zinc (Zn) content on treatment of seeds with ZnONPs (20 mg L−1) concentration as compared to bulk ZnSO4 and control treatments was observed. The application of ZnONPs (40 mg L−1) significantly enhanced the total chlorophyll content, available soil nitrogen and phosphorus, neutral detergent fiber (NDF%), and cellulose contents and improved the total soil microbial counts and soil enzyme activities (dehydrogenase, acid and alkaline phosphatase enzyme activities), whereas a significant increase in available soil potassium and zinc contents was recorded under ZnONPs (20 mg L−1) treatments. These findings suggest an encouraging effect on the growth and yield attributing characteristics of fodder maize after ZnONPs seed coating at low concentration. Furthermore, ZnONPs seed coating can also be considered an effective tool for the delivery of Zn micronutrient to fodder maize crop.

Zinc oxide nanoparticles mediated substantial physiological and molecular changes in tomato.

There has long been debate about how nanoproducts meet agricultural requirements. This study aimed to investigate tomato responses to the long-time foliar application of zinc oxide nanoparticles (ZnO-NP; 0 and 3 mgl-1) or bulk type (BZnO). Both ZnO-NP and BZnO treatments, especially the nanoform, were significantly capable of improving growth, biomass, and yield. The ZnO-NP treatment upregulated the expression of the R2R3MYB transcription factor by 2.6 folds. The BZnO and ZnO-NP treatments transcriptionally up-regulated WRKY1 gene by 2.5 and 6.4 folds, respectively. The bHLH gene was also upregulated in response to BZnO (2.3-fold) or ZnO-NP (4.7-fold). Moreover, the ZnO-NP application made a contribution to upregulation in the EREB gene whereas the bulk compound did not make a significant change. Upregulation in the HsfA1a gene also resulted from the ZnO-NP (2.8-fold) or BZnO (1.6-fold) supplementation. The MKK2 and CAT genes displayed a similar upregulation trend in response to the supplements by an average of 3-folds. While the application of ZnO-NP slightly down-regulated the histone deacetylases (HDA3) gene by 1.9-fold, indicating epigenetic modification. The supplements, especially the nano-product, enhanced concentrations of K, Fe, and Zn in both leaves and fruits. The concentrations of Chla, Chlb, and carotenoids were increased in response to the BZnO or ZnO-NP treatments. Likewise, BZnO or ZnO-NP mediated an increase in activity of nitrate reductase and proline content in leaves. These treatments increased soluble phenols and phenylalanine ammonia-lyase activity. With a similar trend, the BZnO or ZnO-NP application improved the activities of catalase and peroxidase enzymes. The reinforcement in metaxylem and secondary tissues resulted from the applied supplements. This study provides comprehensive comparative evidence on how ZnO-NPs may remodel the chromatin ultrastructure and transcription program, and confer stress tolerance in crops. This study also underlines the necessity of providing integrated transcriptome and proteome data in future studies.

Antibacterial activities of synthesised Zno nanoparticles applied on reactive dyed batik fabrics

Batik is an Indonesian traditional cloth which has been recognised as an Intangible Cultural Heritage of Humanity by UNESCO for more than a decade. Batik cloth is popular among Indonesian people for daily use, both for formal and informal occasions. Commonly, batik cloth is made from cotton, which has many advantages, however prone to bacterial growth, particularly in the tropical climate. Therefore, it is important to develop batik cloth with antibacterial properties. The antibacterial properties of batik cloth were achieved by applying ZnO nanoparticles as antibacterial agent. The nanoparticles were synthesised using precipitation-sonication method. The formed ZnO nanoparticles were in an average particle size of 54.76 nm and 99.77% ZnO content. The batik making process utilized a synthetic reactive dye of remazol-turquoise blue. The effect of process sequence, the level of antibacterial properties, the morphology of the ZnO coated fabric, and the effect of the application of nanoparticle on the dyeing process were investigated. The results showed that ZnO nanoparticle application on the batik fabric led to antibacterial properties. The process sequences in adding the ZnO nanoparticles were confirmed to significantly affect the antibacterial effectivity and the colour strength. The application of ZnO nanoparticles did not affect the colour fastness to washing as the test showed similar value to that of without ZnO treatment. In addition, the application of ZnO nanoparticles affects the mechanical properties by increasing the tensile strength and decreasing the elongation at break. The application of ZnO after batik making process was shown to have a greater effect on the mechanical properties.

A review on application of ZnO nano particles as biosensors

Recently some of the metal nano composites are used in the semiconductor based electrical, electrochemical and optical bio-sensors. ZnO nano particles have drawn great interest due to its unique properties like low cost, wide range of band gap, biocompatible, easy to synthesize in different size and shapes and catalytic surface activity. The surface of the ZnO nano particles are perfect for immobilisation of bio molecules without hampering their biological activity. This property increase the sensitivity of bio-sensors. In this review we highlight the use of different ZnO nano particles in bio-sensors enhancing the efficiency of Bio-sensors.

Zinc oxide nanoparticles promotes liver cancer cell apoptosis through inducing autophagy and promoting p53.

Emerging evidence has highlighted the promising potential of the application of Zinc Oxide nanoparticles (nano-ZnO) but the mechanism by how it functions in liver cancer remains elusive. We aimed to explore the effect of nano-ZnO on liver cancer cells. Liver cancer cells Huh7 cells were transfected with GFP-LC3, and then, treated with DMSO, Sorafenib, and nano-ZnO respectively to set blank group, Sorafenib control group, and nano-ZnO group followed by the analysis of the expression of GFP-LC3, p53, and Caspase by Western blot and RT-qPCR, cell apoptosis and viability by flow cytometry and CCK-8 assay. With a diameter of nano-ZnO 14.13±0.92 nm, the amount of GFP-LC3 protein was increased after treatment of nano-ZnO. Besides, the expressions of GFP-LC3, p53, and Caspase in Sorafenib group and nano-ZnO group were significantly higher than that of control group, while their levels were highest in nano-ZnO group (p<0.05). In nano-ZnO group, the values of D450nm at 24 h, 48h, and 72 h were 0.56±0.06, 0.39±0.05, and 0.22±0.04, respectively, and the apoptotic rate (83.11±2.79%) was significantly lower than that of blank group and control group. Nano-ZnO induced autophagy, upregulated the p53 gene, and facilitated the apoptosis of liver cancer cells, indicating that nano-ZnO might be a therapeutic approach for the treatment of liver cancer patients.

An overview of recent progress in dental applications of zinc oxide nanoparticles.

Nanotechnology is an emerging field of science, engineering, and technology concerning the materials in nanoscale dimensions. Several materials are used in dentistry, which can be modified by applying nanotechnology. Nanotechnology has various applications in dentistry to achieve reliable treatment outcomes. The most common nanometals used in dental materials are gold, silver, copper oxide, magnesium oxide, iron oxide, cerium oxide, aluminum oxide, titanium dioxide, and zinc oxide (ZnO). ZnO nanoparticles (NPs), with their unparalleled properties such as high selectivity, enhanced cytotoxicity, biocompatibility, and easy synthesis as important materials were utilized in the field of dentistry. With this background, the present review aimed to discuss the current progress and gain an insight into applications of ZnO NPs in nanodentistry, including restorative, endodontic, implantology, periodontal, prosthodontics, and orthodontics fields.

Effect of Zinc Priming on Salt Response of Wheat Seedlings: Relieving or Worsening?

In an attempt to alleviate salt-induced damage, the application of ZnO nanoparticles has been suggested. As the use of these particles has also been associated with phytotoxicity, to better clarify the effect of zinc and its possible mitigation of salt stress, we treated wheat seedlings with ZnO (nanoparticles or their bulk-scale counterparts, amended either in the growth medium, NPs and B, or sprayed on the leaves, SPNPs and SPB) with or without subsequent treatment with salt. Growth, photosynthetic parameters, zinc and ion concentration, and in situ and biochemical determination of oxidative stress in wheat leaves and/or in roots were considered. Both Zn and NaCl significantly inhibited growth and induced severe alterations in root morphology. Oxidative stress and damage decreased or increased under ZnO treatment and in saline conditions depending on the organ and on the size and mode of application of particles. In spite of the higher stress conditions often recorded in treated leaves, neither pigment concentration nor photochemical efficiency were decreased. A large variability in the effects of ZnO treatment/priming on seedling salt response was recorded; however, the presence of a cumulative negative effect of priming and salt stress sometimes observed calls for caution in the use of ZnO in protection from saline stress.

Synthesis, characterization and tribological study of zinc oxide nanoparticles

This work presents and discusses the study of ZnO (zinc oxide) as nanoparticles and its idiosyncratic characteristics. Zinc oxide nanoparticles were synthesized employing a facile Sol- gel method, with zinc chloride, zinc nitrate and sodium hydroxide at room temperature as starting materials .The prepared ZnO nanoparticles were then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) ,UV–visible spectroscopy and Fourier transform infrared (FTIR) spectroscopy.SEM and TEM images provide morphological interpretation of the synthesized nanoparticles while its average crystalline size was ascertained from XRD peaks at full width at half maximum and incorporating the Debye-Scherrer’s model. Moreover, interpretation through UV–Visible absorption spectra supported a high absorption confirming its transcendent electrical and optoelectronic properties. The spectral characteristic peaks of the produced zinc oxide nanoparticles were studied using Fourier transform infrared (FTIR) spectroscopy at optimum condition. This paper further focuses on the application of zinc oxide nanoparticles on improving tribological performance as lubricant additives on the grounds of smoothing out the shearing surface and improving colloidal stability.

Application of Zinc Oxide Nanoparticles and Plant Growth Promoting Bacteria Reduces Genetic Impairment under Salt Stress in Tomato (Solanum lycopersicum L. ‘Linda’)

Salinity is an edaphic stress that dramatically restricts worldwide crop production. Nanomaterials and plant growth-promoting bacteria (PGPB) are currently used to alleviate the negative effects of various stresses on plant growth and development. This study investigates the protective effects of different levels of zinc oxide nanoparticles (ZnO-NPs) (0, 20, and 40 mg L−1) and PGPBs (no bacteria, Bacillus subtilis, Lactobacillus casei, Bacillus pumilus) on DNA damage and cytosine methylation changes in the tomato (Solanum lycopersicum L. ‘Linda’) seedlings under salinity stress (250 mM NaCl). Coupled Restriction Enzyme Digestion-Random Amplification (CRED-RA) and Randomly Amplified Polymorphic DNA (RAPD) approaches were used to analyze changes in cytosine methylation and to determine how genotoxic effects influence genomic stability. Salinity stress increased the polymorphism rate assessed by RAPD, while PGPB and ZnO-NPs reduced the adverse effects of salinity stress. Genomic template stability was increased by the PGPBs and ZnO-NPs application; this increase was significant when Lactobacillus casei and 40 mg L−1 of ZnO-NPs were used.A decreased level of DNA methylation was observed in all treatments. Taken together, the use of PGPB and ZnO-NPs had a general positive effect under salinity stress reducing genetic impairment in tomato seedlings.

Effect of zinc oxide nanoparticles embedded NPK fertilizer on growth, yield and zinc concentration and uptake of aromatic rice (Oryza sativa)

Application of ZnO nanoparticles in conjunction with NPK fertilizers helped in increasing growth parameters, enhancement in Zn concentration in rice grain and straw and also grain yield and could save a significant amount of nutrients. As highest grain yield was recorded with application of 100% NPK + 7.5 g ZnO Nps/ha which was statistically at par with 75% NPK + 7.5 g ZnO Nps/ha, hence it can be concluded that application of 75% NPK + 7.5 g ZnO Nps/ha is best as it required 25% less NPK. Likewise, ZnO nanoparticles application had a significant effect on Zn concentrations. Therefore, it can be inferred that ZnO nanoparticles application embedded with NPK fertilizer can save nutrients, increase nutrient concentration and also profit can be accrued due to less requirement of nutrients than recommended dose of fertilizers.

Application of zinc oxide nanoparticles on productive performance in rabbit nutrition: A Review

Nowadays, nanotechnology is more frequently used with the presence of new tools for utilizing nanoparticle-sized essential elements, enhancing the animal’s ability to absorb these elements and thereby improving their productive and reproductive performance. Zinc oxide nanoparticles (Nano-ZnO) can promote productive performance, act as antibacterial agents, and influence the immunity and reproduction of the rabbits. Moreover, zinc (Zn) increases semen volume, total live sperm concentration, percentage of sperm motility, and conception rate in heat-stressed rabbits. Several studies have already reported the effects of low and high zinc doses on rabbit performance. The most observed and analyzed reproductive performance variables are semen quality, spermatogonia, and meiosis of spermatocytes. Most of the studies showed slight positive effects; however, significant results were rare. Since there are almost unlimited possibilities regarding the zinc dosage, further research is still required. Nano-sized zinc particles can be used at low doses, resulting in better outcomes than conventional zinc sources. This review provides an overview of and illustrates the positive effects of zinc nanoparticles and their potential application as a mineral supplement to rabbit diets.

Aggregation behavior of zinc oxide nanoparticles and their biotoxicity to Daphnia magna: Influence of humic acid and sodium alginate

The widespread applications of zinc oxide nanoparticles (ZnO NPs) have raised increasing concerns due to their adverse environmental effects. The ubiquitous natural organic matter in natural aqueous environments can interact with ZnO NPs, thereby affecting their aggregation, sedimentation and biotoxicity. Here, we systematically investigated the effects of humic acid (HA) and sodium alginate (SA) on the aggregation behavior of ZnO NPs and their biotoxicity to Daphnia magna. High concentrations (9.0 mg/L) of HA and SA accelerated the aggregation of ZnO NPs with maximum aggregation rates (ΔD/Δt) of 22.1 and 19.2 nm/min, respectively. Both HA and SA led to 31.2% and 30.1% decrease of ZnO NPs concentration compared with the control experiment. The results calculated by Derjaguin-Landau-Verwey-Overbeek theoretical formula were consistent with these of aggregation and sedimentation of ZnO NPs. Furthermore, excitation-emission-matrix fluorescence spectroscopy verified that the carboxylic groups of HA and SA have high complexation capacity with ZnO NPs. Daphnia magna was used to evaluate the biotoxicity of ZnO NPs, and the toxicity of ZnO NPs to Daphnia magna was alleviated as the HA concentration increased from 0 to 1.2 mg/L. Toxicity mitigation experiments confirmed that photocatalytic generation of reactive oxygen species was more toxic to Daphnia magna than dissolved Zn2+ in acute and chronic toxicity tests. Moreover, the attacks of active oxygen free radical damaged the antioxidant system of Daphnia magna. The information obtained will help us to improve the understanding of the impacts of ZnO NPs on freshwater ecosystems.

Synthesis, characterization and cytotoxicity of zinc oxide nanoparticles by green synthesis method

The use of engineered nanoparticles (NPs) has increased considerably because of their almost universal applications, such as electronics, optical, pharmaceutical, biomedical and energy fields, which have been expanding rapidly during the past few decades. Due to the widespread applications of zinc oxide nanoparticles (ZnONPs), the potential exposure of workers, consumers and scientists to these particles has increased. We conducted a ZnONPs synthesis through a low cost, eco-friendly and sustainable method, where Beta vulgaris extract was utilized as a reducing agent. Characterization of ZnONPs was conducted by High-Resolution Transmission Electron Microscopy (HRTEM), Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis (XRD) to obtain the morphological properties. In this study, we evaluate ZnONPs toxicity in vitro in two mouse fibroblast cell lines C2C12 and L929 myoblast cell lines and human lymphocytes from peripheral blood (HLPB), using Trypan blue dye exclusion method. MTT assay method only in cell lines C2C12 and L929 after 24 h of exposure. The results show the ZnONPs size was between 16 and 24 nm, with hexagonal crystal structure and semi-spherical morphology. The toxic effects of ZnONPs were analyzed in the two cell lines after a 24 and 48 h incubation period. The value of TC50 ZnONPs was calculated after a 24 h exposure, which was found to be between 28 and 37 μg/mL and 20–30 μg/mL at a 48 h exposure. The viability value was reported non toxic at concentrations of 1 × 10−6-1x10−3 μg/mL.

Laboratory and Commercial Synthesized Zinc Oxide Nanoparticles Adsorption onto Coconut Husk: Characterization, Isotherm, Kinetic, and Thermodynamic Studies

The accelerating application of zinc oxide nanoparticles (ZnO-NPs) has called for attention to their potential environmental and human health risks. This work aimed to investigate the sorption efficiency of laboratory and commercial synthesized nanocrystalline zinc oxide onto raw coconut husk in a batch adsorption study. Characterization of samples was performed by employing spectroscopies techniques such as X-ray Diffraction Spectroscopy, Field Emission Scanning Electron Microscopy, Transmission Electron Spectroscopy, Fourier transform IR Spectroscopy, and Brunauer–Emmett–Teller. A spherical shaped nanocrystalline ZnO with a mean crystallite and particle size of 14.7 nm and 24 nm by XRD and TEM was synthesized as compared to the commercial ZnO-NPs of size &lt; 50 nm. The maximum percentage removal of 88% (0.13 mg/g) and 90% (0.16 mg/g) for laboratory synthesized and commercial ZnO-NPs respectively was recorded at an optimum contact time of 80 minutes. The data also indicated 2.0 g sorbent mass and pH of 8 as the optimum conditions for maximum percentage removal of these nanoparticles. Both Langmuir and Freundlich models fitted best for laboratory synthesized ZnO-NPs with a maximum capacity of 0.797 mg/g, whereas Langmuir isotherm model alone with a maximum capacity of 0.710 mg/g fitted well for commercial ZnO-NPs. The n-value from the Freundlich model, as well as separation factor (RL) were greater than unity suggesting a favorable adsorption process. The study obeyed pseudo-second-order, which was exothermic with a high degree of freedom of sorbent-sorbate interaction. The results suggested that coconut husk is potentially scalable for removing ZnO-NPs from wastewater.

Green synthesis of zinc oxide nanoparticles from the leaf, stem and in vitro grown callus of Mussaenda frondosa L.: characterization and their applications.

Biosynthesis of zinc oxide nanoparticles (ZnO-NPs) was achieved by utilizing the reducing and capping potential of leaf, stem and callus aqueous extracts of Mussaenda frondosa.The bioreduced ZnO-NPs were characterized using powder X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis spectroscopy), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS) techniques. UV–visible spectra of ZnO-NPs showed a strong absorption peak at 370, 376 and 373 nm corresponding to the band gap energy of 3.33, 3.27 and 3.30 eV for ZnO-NPs obtained from leaf (L-ZnO-NP), stem (S-ZnO-NP) and callus (C-ZnO-NP) aqueous extracts, respectively. XRD analysis confirmed the formation of hexagonal wurtzite structures having an average grain size between 5 and 20 nm in diameter. FTIR spectra revealed the presence of stretching vibrations of –O–H, C–H, C–N, C = O groups involved in reduction and stabilization of nanoparticles. SEM images recognize the presence of spongy, spherical, porous agglomerated nanoparticles. DLS analysis and zeta potential values validated the stability of ZnO-NPs. The present investigation puts light on the photocatalytic activity and biological (antioxidant, anti-inflammatory, antidiabetic, antimicrobial, anticancerous) applications of ZnO-NPs. The current study is an attempt to describe an effective, simple and eco-friendly method of ZnO-NP synthesis and to evaluate its potential for various industrial and medical applications.Electronic supplementary materialThe online version of this article (10.1007/s13204-020-01382-2) contains supplementary material, which is available to authorized users.

TRPC6-Mediated Ca2+ Entry Essential for the Regulation of Nano-ZnO Induced Autophagy in SH-SY5Y Cells.

Recently, possible applications of zinc oxide nanoparticles (nano-ZnO) have been extensively studied owing to their ease of synthesis. However, the effect of nano-ZnO on the nervous system remains unclear. This study investigates the action of nano-ZnO on SH-SY5Y neuroblastoma cells. We found that nano-ZnO (0-50 µg/mL) induced a significant decrease in cell survival rate in a dose-dependent manner, and increased LC3 puncta formation. However, the apoptosis was not affected by nano-ZnO, because the protein levels of cytochrome c, caspase-3, Bcl-xL, and BAX were not varied by the nano-ZnO treatment. Nano-ZnO increased Ca2+ entry and the expression of TRPC6.The results suggested that nano-ZnO increased [Ca2+] through the TRPC-dependent Ca2+ influx, since Ca2+ influx can be prevented by the TRPC inhibitor. Furthermore, cells on nano-ZnO-treatment groups displayed loss of F-actin in a dose dependent manner, which also could be prevented by TRPC inhibitor. Herein, we demonstrated that the nano-ZnO activated TRPC6 channel, thereby increasing the Ca2+ flux and resulting in increased autophagy. Nano-ZnO could have possible anticancer effects in neuroblastoma by inhibiting the proliferation of tumor cells. However, we should also pay attention toward the biosecurity of nano materials.

Gene Expression Profiling of the Liver and Lung in Mice After Exposure to ZnO Quantum Dots.

IntroductionZnO quantum dots (QDs) have drawn much attention recently as they are Cd-free, low-cost, and have excellent optical properties. With the expanded production and application of ZnO nanoparticles, concerns about their potential toxicity have also been raised.Materials and MethodsWe used RNA sequencing (RNA-seq) to analyze the global gene expression of liver and lung tissues after ZnO QDs treatment. Differentially expressed genes (DEGs) were screened, with a fold change >1.5 and padj <0.05. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed, and padj <0.05 was considered significantly enriched. The RNA-seq results were validated by quantitative real-time polymerase chain reaction (qRT-PCR).ResultsA total of 47 and 218 genes were significantly differentially expressed in the liver and lung. Eight GO terms were enriched in the liver and lung, and retinol metabolism and the peroxisome proliferator-activated receptor (PPAR) signaling pathway were shared in different tissues.DiscussionAccording to DEGs and pathway enrichment analyses, inflammation might be induced in liver and lung tissues after intravenous injection of ZnO QDs. These findings will be helpful for future research and application of ZnO QDs.

Modification of cotton fabric by ZnO nanoparticles for producing an antibacterial natural dyed batik

Batik is a traditional Indonesian cloth that has been recognized by UNESCO as the Intangible Cultural Heritage of Humanity on October 2, 2009. Nowadays batik with natural dyes is preferred because it is unique, natural and environmentally friendly. The disadvantage of natural dyed batik, especially those using cotton cloth, is easily overgrown with bacteria. This paper presents the results of research on the application of ZnO nanoparticles on cotton fabrics that produce batik with antibacterial activity. The application of ZnO nanoparticles was carried out with variations on concentration (1% and 2%), temperature (25°C and 80°C), and application stages, i.e before and after the batik process. Colouring process was conducted by natural dyes of Tingi (Ceriops tagal). To see the effect of ZnO application, the antibacterial activity, the colour fastness to washing, the colour strength (K/S) of natural dyed batik have been examined. The results showed that the ZnO application before and after the batik process can provide antibacterial activity and enhance colour strength on natural dyed batik. To maintain the colour fastness to washing, the ZnO application can be carried out before the batik process at temperature 80°C or after the batik process at 25°C.

Fabricating ZnO/lignin-derived flower-like carbon composite with excellent photocatalytic activity and recyclability

The application of ZnO nanoparticles as photocatalyst is significantly hampered by limited absorption range for solar spectrum, fast recombination of photogenerated carriers and poor recyclability. The modification with carbon structures has attracted attention as their advantageous performance in photocatalysis. Herein, we first report a lignin-derived flower-like carbon (LFC), which is used to modify ZnO. The resulting composite (ZnO/LFC) is composed of ZnO nanoparticles (∼10 nm) embedded on a flower-like carbon consisting of two-dimensional corrugated nanosheets. Especially, LFC exhibits stable three-dimensional structure and rich oxygen-containing functional groups. So ZnO can be uniformly anchored on the LFC. Composite presents an extended optical absorption and enhanced separation of photogenerated carriers due to the interface electronic interaction between ZnO and LFC. The hierarchical flower-like structure facilitates fast substance transfer and high light-harvesting efficiency. Therefore, ZnO/LFC presented an excellent photocatalytic activity toward degradation of sulfamethazine and hydrogen evolution, which were about 3.0 and 2.1 times that of pure ZnO, respectively. Moreover, the recyclability of composite photocatalyst was also significantly better than pure ZnO. This work not only provides a facile, low-cost and scalable strategy to promote practical application of photocatalyst but also opens new path toward the high-value utilization of industrial lignin.

Nano-ZnO-Induced Drought Tolerance Is Associated with Melatonin Synthesis and Metabolism in Maize.

The applications of ZnO nanoparticles in agriculture have largely contributed to crop growth regulation, quality enhancement, and induction of stress tolerance, while the underlying mechanisms remain elusive. Herein, the involvement of melatonin synthesis and metabolism in the process of nano-ZnO induced drought tolerance was investigated in maize. Drought stress resulted in the changes of subcellular ultrastructure, the accumulation of malondialdehyde and osmolytes in leaf. The nano-ZnO (100 mg L−1) application promoted the melatonin synthesis and activated the antioxidant enzyme system, which alleviated drought-induced damage to mitochondria and chloroplast. These changes were associated with upregulation of the relative transcript abundance of Fe/Mn SOD, Cu/Zn SOD, APX, CAT, TDC, SNAT, COMT, and ASMT induced by nano-ZnO application. It was suggested that modifications in endogenous melatonin synthesis were involved in the nano-ZnO induced drought tolerance in maize.