Improvement of Commercially Valuable Traits of Industrial Crops by Application of Carbon-based Nanomaterials

Gelatin Nanoparticles can Improve Pesticide Delivery Performance to Plants

Nanomaterials associated with plant growth and crop cultivation revolutionize traditional concepts of agriculture. However, the poor reiterability of these materials in agricultural applications necessitates the development of environmentally-friendly approaches. To address this, biocompatible gelatin nanoparticles (GNPs) as nanofertilizers with a small size (≈150 nm) and a positively charged surface (≈30 mV) that serve as a versatile tool in agricultural practices is designed. GNPs load agrochemical agents to improve maintenance and delivery. The biocompatible nature and small size of GNPs ensure unrestricted nutrient absorption on root surfaces. Furthermore, when combined with pesticides, GNPs demonstrate remarkable enhancements in insecticidal (≈15%) and weed-killing effects (≈20%) while preserving the efficacy of the pesticide. That GNPs have great potential for use in sustainable agriculture, particularly in inducing plant growth, specifically plant root growth, without fertilization and in enhancing the functions of agrochemical agents is proposed. It is suggested conceptual applications of GNPs in real-world agricultural practices.

Effects of Graphene-Based Metal Composite and Urea on Seed Germination and Performance of Berberis chitria Buch.-Ham. ex Lindl

Being an important source of berberine, Berberis chitria Buch.-Ham. ex Lindl. (Berberidaceae) has high demand in pharmaceutical industries. Its populations are diminishing due to overexploitation, habitat loss, slow-growing nature, and climate change. It is important to develop propagation protocols to sustain its natural populations and ensure its survival in the future. Fertilizers play an essential role in the yield and productivity of different crops. Among others, urea is the most abundantly used fertilizer in crops. Its effects on the yield and survival of medicinal plants are poorly studied. However, it is known that applying urea for a long time affects the soil negatively. Due to these negative effects, alternative fertilizers such as graphene-based metal composite (GMC) are being tested for their efficiency. In the present study, for the first time, we tested the effects of urea and GMC on the germination and performance of B. chitria. GMC showed maximum germination at 30 ppm (75%) and urea at 15 ppm (79%). Findings reveal non-significant effects of GMC and urea on germination and performance of B. chitria, suggesting the use of GMC as an alternative fertilizer.

Graphene enhances artemisinin production in the traditional medicinal plant Artemisia annua via dynamic physiological processes and miRNA regulation

We investigated the effects of graphene on the model herb Artemisia annua, which is renowned for producing artemisinin, a widely used pharmacological compound. Seedling growth and biomass were promoted when A. annua was cultivated with low concentrations of graphene, an effect which was attributed to a 1.4-fold increase in nitrogen uptake, a 15%-22% increase in chlorophyll fluorescence, and greater abundance of carbon cycling-related bacteria. Exposure to 10 or 20 mg/L graphene resulted in a ∼60% increase in H2O2, and graphene could act as a catalyst accelerator, leading to a 9-fold increase in catalase (CAT) activity in vitro and thereby maintaining reactive oxygen species (ROS) homeostasis. Importantly, graphene exposure led to an 80% increase in the density of glandular secreting trichomes (GSTs), in which artemisinin is biosynthesized and stored. This contributed to a 5% increase in artemisinin content in mature leaves. Interestingly, expression of miR828 was reduced by both graphene and H2O2 treatments, resulting in induction of its target gene AaMYB17, a positive regulator of GST initiation. Subsequent molecular and genetic assays showed that graphene-induced H2O2 inhibits micro-RNA (miRNA) biogenesis through Dicers and regulates the miR828-AaMYB17 module, thus affecting GST density. Our results suggest that graphene may contribute to yield improvement in A. annua via dynamic physiological processes together with miRNA regulation, and it may thus represent a new cultivation strategy for increasing yield capacity through nanobiotechnology.

Graphene promotes the growth of Vigna angularis by regulating the nitrogen metabolism and photosynthesis

Graphene has promising applications in agriculture and forestry. In the current study, six different concentrations of graphene (0mg/L, 0.01mg/L, 0.10mg/L, 1.00mg/L, 10.00mg/L, and 100.00mg/L) were used to investigate its effect on the growth and development of V. angularis plants in soil culture. The results showed that the group treated with 1.00mg/L graphene (G-1) had significantly increased plant height (19.86%), stem diameter (24.33%), and leaf area (13.69%), compared to the control group (CK). Moreover, all concentrations of graphene had positive effects on the total root length, total root surface area, and the number of root tips of V. angularis. Compared to the CK group, the G-1 group had significantly increased leaf water potential (37.89%), leaf conductivity (2.25%), and SOD, POD, and CAT activities (47.67%, 35.22%, and 199.3%, respectively). The G-1 group also showed improved leaf net photosynthetic rate, chlorophyll content, and soluble sugar content (51.28%, 24.25%, and 38.35%, respectively), compared to the CK group. Additionally, 1.00mg/L graphene led to a 23.88% increase in the podding rate and a 17.04% increase in the yield of V. angularis plants. The rhizosphere soil of V. angularis treated with 1.00mg/L graphene had a 25.14% increase in hydrolyzable nitrogen content and a 66.67% increase in available phosphorus content. RNA-seq data indicated that 1.00mg/L graphene induced the expression of photosynthesis and nitrogen transmembrane transport genes, including ATP synthase subunit b, photosystem I reaction center subunit XI, photosystem I reaction center subunit IV A, ferredoxin, and psbP-like protein 1, as well as genes for photosynthesis antenna proteins, glutamine synthetase, glutamate dehydrogenase 1, cyanate hydratase, protein fluG-like, and NRT1/PTR family, suggesting that graphene promoted the growth and development of V. angularis by enhancing the photosynthesis and nitrogen metabolism processes in V. angularis plants. Our results indicated that a suitable concentration of graphene could significantly promote the growth of V. angularis plants in soil.

Regulatory effect of graphene on growth and carbon/nitrogen metabolism of maize (Zea mays L.)

BACKGROUND

Leakage of graphene into the environment has resulted from its increasing use. Although the impact of graphene on ecosystems is already in full swing, information regarding its impact on plants is lacking. In particular, the effects of graphene on plant growth and development vary, and basic information on the regulation of carbon and nitrogen metabolism is missing. In the current study, the way in which graphene (0, 25, 50, 100, and 200 g kg-1 ) affects maize seedlings was studied in terms of morphological and biochemical indicators. The purpose of this study was to understand better how graphene regulates plant carbon and nitrogen metabolism and to understand its interactions with leaf structure and plant growth.

RESULTS

The results showed that 50 g kg-1 graphene increased plant height, stem diameter, leaf area, and dry weight; however, this was inhibited by the high level of graphene (200 g kg-1 ). Further studies indicated that different concentrations of graphene could increase leaf thickness and vascular bundle area as well as the net photosynthetic rate (Pn) of leaves; 25 and 50 g kg-1 graphene enhanced the leaves stomatal conductance (Cond), transpiration rate (Tr), intercellular carbon dioxide (Ci), and chlorophyll content. Higher concentrations decreased the above indicators. At 50 g kg-1 , graphene increased the activity of carbon/nitrogen metabolism enzymes by increasing carbon metabolites (fructose, sucrose, and soluble sugars) and soluble proteins (nitrogen metabolites). These enzymes included sucrose synthase (SS), sucrose phosphate synthase (SPS), nitrate reductase (NR), glutamine synthase (GS), and glutamate synthase (GOGAT).

CONCLUSION

These results indicate that graphene can regulate the activities of key enzymes involved in carbon and nitrogen metabolism effectively and supplement nitrogen metabolism through substances produced by carbon metabolism by improving photosynthetic efficiency, thus maintaining the balance between carbon and nitrogen and promoting plant growth and development. The relationship between these indexes explained the mechanism by which graphene supported the growth of maize seedlings by enhancing photosynthetic carbon metabolism and maintaining metabolic balance. For maize seedling growth, graphene treatment with 50 g kg-1 soil is recommended. © 2023 Society of Chemical Industry.

Graphene oxide decreases the effects of salt stress on Persian clover seed germination

Among biotic and abiotic stresses, the most restrictive for plant distribution is salt stress, where different concentrations might exert harmful effects on seed germination. Recently, nanomaterials were used successfully to mitigate these stresses, indicating that plants may be able to develop normally in adverse conditions. The aim of this study was to examine the effects of graphene oxide (GO) on the germination of Persian clover seedlings under salt stress conditions. Following sown on substrate paper, seeds were tested after exposure to different concentrations of graphene oxide (0, 125, 250, or 500 mg L-1 GO), sodium chloride (0; -0.1; -0.2; -0.3, or -0.4 MPa NaCl) and/or GO + salt concomitantly, and then stored for 7 days in a germination chamber at 20°C in the presence of light. Seed germination and growth parameters of seedlings were determined. Graphene oxide demonstrated protective effect against salt stress as evident by no marked adverse effects on seed germination where GO blocked the salt-induced reduction in germination. The results obtained provide references for the safe application of nanomaterials and emphasize the significance of GO as a promising material for reducing the toxicity of salts in agriculture.

Selenium nanoparticles based on Amphipterygium glaucum extract with antibacterial, antioxidant, and plant biostimulant properties

BACKGROUND

In recent years, crop production has expanded due to the variety of commercially available species. This increase in production has led to global competition and the search for biostimulant products that improve crop quality and yield. At the same time, agricultural products that protect against diseases caused by phytopathogenic microorganisms are needed. Thus, the green synthesis of selenium nanoparticles (SeNPs) is a proposal for achieving these needs. In this research, SeNPs were synthesized from methanolic extract of Amphipterygium glaucum leaves, and chemically and biologically characterized.

RESULTS

The characterization of SeNPs was conducted by ultraviolet-visible spectrophotometry (UV-Vis), scanning electron microscopy (SEM), electron microscopy transmission (TEM), Dynamic Light Scattering (DLS), energy dispersion X-ray spectroscopy (EDX), and infrared spectrophotometry (FTIR) techniques. SeNPs with an average size of 40-60 nm and spherical and needle-shaped morphologies were obtained. The antibacterial activity of SeNPs against Serratia marcescens, Enterobacter cloacae, and Alcaligenes faecalis was evaluated. The results indicate that the methanolic extracts of A. glaucum and SeNPs presented a high antioxidant activity. The biostimulant effect of SeNPs (10, 20, 50, and 100 µM) was evaluated in vinca (Catharanthus roseus), and calendula (Calendula officinalis) plants under greenhouse conditions, and they improved growth parameters such as the height, the fresh and dry weight of roots, stems, and leaves; and the number of flowers of vinca and calendula.

CONCLUSIONS

The antibacterial, antioxidant, and biostimulant properties of SeNPs synthesized from A. glaucum extract demonstrated in this study support their use as a promising tool in crop production.

Plant nanobionics: Fortifying food security via engineered plant productivity

The world's human population is increasing exponentially, increasing the demand for high-quality food sources. As a result, there is a major global concern over hunger and malnutrition in developing countries with limited food resources. To address this issue, researchers worldwide must focus on developing improved crop varieties with greater productivity to overcome hunger. However, conventional crop breeding methods require extensive periods to develop new varieties with desirable traits. To tackle this challenge, an innovative approach termed plant nanobionics introduces nanomaterials (NMs) into cell organelles to enhance or modify plant function and thus crop productivity and yield. A comprehensive review of nanomaterials affect crop yield is needed to guide nanotechnology research. This article critically reviews nanotechnology applications for engineering plant productivity, seed germination, crop growth, enhancing photosynthesis, and improving crop yield and quality, and discusses nanobionic approaches such as smart drug delivery systems and plant nanobiosensors. Moreover, the review describes NM classification and synthesis and human health-related and plant toxicity hazards. Our findings suggest that nanotechnology application in agricultural production could significantly increase crop yields to alleviate global hunger pressures. However, the environmental risks associated with NMs should be investigated thoroughly before their widespread adoption in agriculture.

Effect of graphene oxide on the uptake, translocation and toxicity of metal mixture to Lepidium sativum L. plants: Mitigation of metal phytotoxicity due to nanosorption

Due to its unique structure and exceptional properties, graphene oxide (GO) is increasingly used in various fields of industry and therefore is inevitably released into the environment, where it interacts with different contaminants. However, the information relating to the ability of GO to affect the toxicity of contaminants is still limited. Therefore, the aim of our study was to synthesize GO, to examine the phytotoxicity of different concentrations of GO and its co-exposure with the metal mixture using garden cress (Lepidium sativum L.) as a test organism and to evaluate the potential of GO to affect toxicity of metals and their uptake by plants. The metal mixture (MIX) containing Ni (II), Zn (II), Cr (III) and Cu (II) was prepared in accordance with the maximum-permissible-concentrations (MPC) accepted for the inland waters in the EU. Additionally, the capacity of GO to adsorb metals was studied in specific conditions of the phytotoxicity test and assessed using adsorption isotherms. Our data indicate that in most cases the tested concentrations of MIX, GO and MIX + GO did not affect seed germination, root growth and biomass of roots and seedlings, however, they were found to alter photosynthesis processes, enhance production of carotenoids and H₂O₂ as well as to activate lipid peroxidation. Additionally, our study revealed that GO affects the accumulation of tested metals in roots and shoots of the MIX-exposed L. sativum. This is due to the capacity of GO to adsorb metals from the growth medium. Therefore, low concentrations of GO can be used for water decontamination.

The physio-chemical properties and applications of 2D nanomaterials in agricultural and environmental sustainability

Global hunger and nutritional deficiency demand the advancement of existing and conventional approaches to food production. The application of nanoenabled strategies in agriculture has opened up new avenues for enhancing crop yield and productivity. Recently, two-dimensional (2D) nanomaterials (NMs) have manifested new possibilities for increasing food production and nutrition. Graphene nanosheets, the 2D form of graphene has been exemplary in enhancing the loading capacity of agro-active ingredients, their target-specific delivery, bioavailability, and controlled release with slow degradation, resulting in the increased shelf-life/active time of the agro-active components. Also, the development of novel formulations/composites of MXenes and Transition Metal Dichalcogenides (TMDs) can foster plant growth, metabolism, crop production, protection and improvement of soil quality. Additionally, the 2D NM-based biosensors can monitor the nutrient levels and other parameters affecting agronomical traits in plants. This review provides an insight into the details of 2D NM synthesis and functionalization methods. Notably, the review highlights the broad-range of 2D NM applications and their suitability in the development of nanotechnology-based agriformulations. The 2D NM-based derivatives have shown immense potential in enhancing the pedologic parameters, crop productivity, pest-protection and nutritional value. Thus, assisting in achieving food and environmental sustainability goals.

Comprehensive Risk Assessment of Carbon Nanotubes Used for Agricultural Applications

Carbon-based nanomaterials (CBNs) are often used for potential agricultural applications. Since CBNs applied to plants can easily enter plant organs and reach the human diet, the consequences of the introduction of CBNs into the food chain need to be investigated. We created a platform for a comprehensive investigation of the possible health risks of multiwalled carbon nanotubes (CNTs) accumulated in the organs of exposed tomato plants. Quantification and visualization of CNTs absorbed by plant organs were determined by microwave-induced heating (MIH) and radio frequency (RF) heating methods. Feeding mice with CNT-contaminated tomatoes showed an absence of toxicity for all assessed animal organs. The amount of CNTs accumulated inside the organs of mice fed with CNT-containing fruits was assessed by an RF heating technique and was found to be negligible. Our work provides the experimental evidence that the amount of CNTs accumulated in plant organs as a result of nanofertilization is not sufficient to induce toxicity in mice.

Multi-walled carbon nanotubes wrapped with polyvinylpyrrolidone can control the leaf yellowing of Alstroemeria cut flowers

The rapid yellowing of the leaves on cut flowers with leafy stems severely limits their vase life and commercial value. In this study, the effect of a composite of multi-walled carbon nanotubes (MWCNTs) and polyvinyl pyrrolidone (PVP) on the longevity of cut Alstroemeria flowers (Alstroemeria hybrida) was investigated to obtain a solution to this problem. A range of MWCNTs/PVP composite concentrations (0, 3, 6, and 9 mg L-1) was applied in a vase solution (for 24 h) as pulse treatments. Our findings indicate that the composite of MWCNTs and PVP exhibits excellent dispersibility in a vase solution. The results demonstrate that a 3 mg L-1 MWCNTs/PVP concentration was the most effective, extending the vase life of cut Alstroemeria flowers by up to 27 days. Pulsing with MWCNTs/PVP delayed the onset of floret abscission and leaf yellowing by 5 and 18 days, respectively. Additionally, when MWCNTs/PVP solution was applied to cut stems, water uptake remained consistently greater than that of the control. Additionally, MWCNTs/PVP increased the total chlorophyll content, soluble protein content, and POX enzyme activity of leaves while decreasing the malondialdehyde (MDA) content. The results indicate that this composite exhibited antimicrobial activity against gram-positive and -negative bacteria, particularly at a concentration of 3 mg L-1. This study demonstrated that adding MWCNTs/PVP to a vase solution of Alstroemeria cut flowers increased their longevity with minimal leaf yellowing symptoms compared to untreated cut stems. As a result, this nanocomposite can be used safely and effectively in vase solutions and in combination with other preservatives.

Changes of physico-chemical properties of nano-biomaterials by digestion fluids affect the physiological properties of epithelial intestinal cells and barrier models

Background

The widespread use of nano-biomaterials (NBMs) has increased the chance of human exposure. Although ingestion is one of the major routes of exposure to NBMs, it is not thoroughly studied to date. NBMs are expected to be dramatically modified following the transit into the oral-gastric-intestinal (OGI) tract. How these transformations affect their interaction with intestinal cells is still poorly understood. NBMs of different chemical nature—lipid-surfactant nanoparticles (LSNPs), carbon nanoparticles (CNPs), surface modified Fe₃O₄ nanoparticles (FNPs) and hydroxyapatite nanoparticles (HNPs)—were treated in a simulated human digestive system (SHDS) and then characterised. The biological effects of SHDS-treated and untreated NBMs were evaluated on primary (HCoEpiC) and immortalised (Caco-2, HCT116) epithelial intestinal cells and on an intestinal barrier model.

Results

The application of the in vitro SDHS modified the biocompatibility of NBMs on gastrointestinal cells. The differences between SHDS-treated and untreated NBMs could be attributed to the irreversible modification of the NBMs in the SHDS. Aggregation was detected for all NBMs regardless of their chemical nature, while pH- or enzyme-mediated partial degradation was detected for hydroxyapatite or polymer-coated iron oxide nanoparticles and lipid nanoparticles, respectively. The formation of a bio-corona, which contains proteases, was also demonstrated on all the analysed NBMs. In viability assays, undifferentiated primary cells were more sensitive than immortalised cells to digested NBMs, but neither pristine nor treated NBMs affected the intestinal barrier viability and permeability. SHDS-treated NBMs up-regulated the tight junction genes (claudin 3 and 5, occludin, zonula occludens 1) in intestinal barrier, with different patterns between each NBM, and increase the expression of both pro- and anti-inflammatory cytokines (IL-1β, TNF-α, IL-22, IL-10). Notably, none of these NBMs showed any significant genotoxic effect.

Conclusions

Overall, the results add a piece of evidence on the importance of applying validated in vitro SHDS models for the assessment of NBM intestinal toxicity/biocompatibility. We propose the association of chemical and microscopic characterization, SHDS and in vitro tests on both immortalised and primary cells as a robust screening pipeline useful to monitor the changes in the physico-chemical properties of ingested NBMs and their effects on intestinal cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00491-w.

Advances in Biologically Applicable Graphene-Based 2D Nanomaterials

Climate change and increasing contamination of the environment, due to anthropogenic activities, are accompanied with a growing negative impact on human life. Nowadays, humanity is threatened by the increasing incidence of difficult-to-treat cancer and various infectious diseases caused by resistant pathogens, but, on the other hand, ensuring sufficient safe food for balanced human nutrition is threatened by a growing infestation of agriculturally important plants, by various pathogens or by the deteriorating condition of agricultural land. One way to deal with all these undesirable facts is to try to develop technologies and sophisticated materials that could help overcome these negative effects/gloomy prospects. One possibility is to try to use nanotechnology and, within this broad field, to focus also on the study of two-dimensional carbon-based nanomaterials, which have excellent prospects to be used in various economic sectors. In this brief up-to-date overview, attention is paid to recent applications of graphene-based nanomaterials, i.e., graphene, graphene quantum dots, graphene oxide, graphene oxide quantum dots, and reduced graphene oxide. These materials and their various modifications and combinations with other compounds are discussed, regarding their biomedical and agro-ecological applications, i.e., as materials investigated for their antineoplastic and anti-invasive effects, for their effects against various plant pathogens, and as carriers of bioactive agents (drugs, pesticides, fertilizers) as well as materials suitable to be used in theranostics. The negative effects of graphene-based nanomaterials on living organisms, including their mode of action, are analyzed as well.

New analytical strategies amplified with carbon-based nanomaterial for sensing food pollutants

The most significant topic currently under the moonlight is Nanobiotechnology and engineered nanomaterials. The novel characteristics displayed by engineered Nanomaterials, especially carbon-based nanomaterials, have spurred interest in its potential application in the food industry. It has provided opportunities for finding solutions to the long-standing challenges in the food industry to assess food safety, maintain food quality, extend the shelf life of produce, and efficiently deliver nutrients. Nanomaterials can be incorporated in food sensors facilitating efficient monitoring of crop maturity and detecting biological and chemical contaminants. When integrated into food packages, nanomaterials could aid in assessing the freshness and improving the quality of packaged foods. In addition, more efficient delivery of nutrients could be possible in foods fortified using nano compounds. The initial section of this review gives an overview of the broad application of nanotechnology in the food industry and carbon-based nanomaterials. The latter part focuses on nanotechnology in biosensors for food safety and quality monitoring.

The Effects of Graphene-Family Nanomaterials on Plant Growth: A Review

Numerous reports of graphene-family nanomaterials (GFNs) promoting plant growth have opened up a wide range of promising potential applications in agroforestry. However, several toxicity studies have raised growing concerns about the biosafety of GFNs. Although these studies have provided clues about the role of GFNs from different perspectives (such as plant physiology, biochemistry, cytology, and molecular biology), the mechanisms by which GFNs affect plant growth remain poorly understood. In particular, a systematic collection of data regarding differentially expressed genes in response to GFN treatment has not been conducted. We summarize here the fate and biological effects of GFNs in plants. We propose that soil environments may be conducive to the positive effects of GFNs but may be detrimental to the absorption of GFNs. Alterations in plant physiology, biochemistry, cytological structure, and gene expression in response to GFN treatment are discussed. Coincidentally, many changes from the morphological to biochemical scales, which are caused by GFNs treatment, such as affecting root growth, disrupting cell membrane structure, and altering antioxidant systems and hormone concentrations, can all be mapped to gene expression level. This review provides a comprehensive understanding of the effects of GFNs on plant growth to promote their safe and efficient use.

Metal/Metalloid-Based Nanomaterials for Plant Abiotic Stress Tolerance: An Overview of the Mechanisms

In agriculture, abiotic stress is one of the critical issues impacting the crop productivity and yield. Such stress factors lead to the generation of reactive oxygen species, membrane damage, and other plant metabolic activities. To neutralize the harmful effects of abiotic stress, several strategies have been employed that include the utilization of nanomaterials. Nanomaterials are now gaining attention worldwide to protect plant growth against abiotic stresses such as drought, salinity, heavy metals, extreme temperatures, flooding, etc. However, their behavior is significantly impacted by the dose in which they are being used in agriculture. Furthermore, the action of nanomaterials in plants under various stresses still require understanding. Hence, with this background, the present review envisages to highlight beneficial role of nanomaterials in plants, their mode of action, and their mechanism in overcoming various abiotic stresses. It also emphasizes upon antioxidant activities of different nanomaterials and their dose-dependent variability in plants' growth under stress. Nevertheless, limitations of using nanomaterials in agriculture are also presented in this review.

Biofertilizers and nanofertilizers for sustainable agriculture: Phycoprospects and challenges

Increased food demands and ceasing nutrient deposits have resulted in a great shortfall between the food supply and demand and would be worse in the years to come. Higher inputs of synthetic fertilizers on lands have resulted in environmental pollution, persistent changes in the soil ecology, and physicochemical conditions. This has greatly decreased the natural soil fertility thereby hindering agricultural productivity, human health, and hygiene. Bio-based resilient nutrient sources as wastewater-derived algae are promising as a complete nutrient for agriculture and have the potential to be used in soilless cultivations. Innovations in nano-fortification and nano-sizing of minerals and algae have the potential to facilitate nutrients bioavailability and efficacy for a multifold increase in productivity. In this context, various options on minerals nanofertilizer application in agricultural food production besides efficient biofertilizer have been investigated. Algal biofertilizer with the nanoscale application has huge prospects for further agriculture productivities and fosters suitable development.

Implication of Wood-Derived Hierarchical Carbon Nanotubes for Micronutrient Delivery and Crop Biofortification

A similarity of metal alloy encapsulation with the micronutrient loading in carbon nanoarchitecture can be fueled by exploring carbon nanocarriers to load micronutrient and controlled delivery for crop biofortification. A wood-derived nanoarchitecture model contains a few-graphene-layer that holds infiltrated alloy nanoparticles. Such wood-driven carbonized framework materials with legions of open porous architectures and minimized-tortuosity units further decorated carbon nanotubes (CNTs), which originate from heat treatment to carbonized wood samples. These wood-derived samples can alleviate micronutrient nanoparticle permeation and delivery to the soil. A rapid heat shock treatment can help in distributing N-C-NiFe metal alloy encapsulation in carbon frameworks uniformly in that case; higher heating and rapid extinction of heat shock have led to formation of good dispersion of nanoparticles. The wood-carbon framework decorated with metal alloys displays promising electrocatalytic features and cyclic stability for hydrogen evolution. Envisaged from this strategy, we obtain enough evidence to form an opinion that a singular heat shock process can even lead to a strategy of faster growth of a wood-carbon network with well-dispersed micronutrient metal salts in porous matrices for high-efficiency delivery to the soil. Having envisaged the formation of ultrafine nanoparticles with a good dispersion profile in the case of transition metals and alloy encapsulation in the carbon network due to the rapid heating and quenching rates, we anticipate that the loading of micronutrients in the wood-derived nanoarchitecture of carbonized wood derived carbon nanotube (CW-CNT), which can offer an application in seed germination and enhance growth rates of crops. The experience of controlled experiments on germination of tomato seeds on a medium containing CW-CNT that can diffuse the seed coat with the promotion of water uptake inside seeds for enhanced germination and growth of tomato seedlings can be further extended to cereal crops.

Effects of graphene on morphology, microstructure and transcriptomic profiling of Pinus tabuliformis Carr. roots

Graphene has shown great potential for improving growth of many plants, but its effect on woody plants remains essentially unstudied. In this work, Pinus tabuliformis Carr. bare-rooted seedlings grown outdoors in pots were irrigated with a graphene solution over a concentration range of 0-50 mg/L for six months. Graphene was found to stimulate root growth, with a maximal effect at 25 mg/L. We then investigated root microstructure and carried out transcript profiling of root materials treated with 0 and 25 mg/L graphene. Graphene treatment resulted in plasma-wall separation and destruction of membrane integrity in root cells. More than 50 thousand of differentially expressed genes (DEGs) were obtained by RNA sequencing, among which 6477 could be annotated using other plant databases. The GO enrichment analysis and KEGG pathway analysis of the annotated DEGs indicated that abiotic stress responses, which resemble salt stress, were induced by graphene treatment in roots, while responses to biotic stimuli were inhibited. Numerous metabolic processes and hormone signal transduction pathways were altered by the treatment. The growth promotion effects of graphene may be mediated by encouraging proline synthesis, and suppression of the expression of the auxin response gene SMALL AUXIN UP-REGULATED RNA 41 (SAUR41), PYL genes which encode ABA receptors, and GSK3 homologs.

Comparative study of response of four crop species exposed to carbon nanotube contamination in soil

Crop plants are exposed to a variety of contaminants through sewage sludge spreading but very little is known about the impact of emerging contaminants such as nanomaterials. To date their impact on plants is still very controversial with many works claiming negative impacts while some authors suggest their use as plant growth regulator in agriculture. In this study, aiming to better understand where these discrepancies may come from, we investigated the influence of plant species (tomato, rapeseed, cucumber and maize) on plant response to a carbon nanotube contamination in soil condition. Our results demonstrate that the same CNT contamination can lead to different effects depending on plant species with positive impacts on cucumber and rapeseed (more than 50% increase in leaf biomass and surface area and 29% increase in chlorophyll for cucumber) but negative impact on maize (-14% for plant height), while tomato was insensitive. FTIR analysis of biomacromolecule composition suggested that these differences could be related with plant cell wall composition (in particular: pectins, xyloglucans and lignins). As a summary, no overall conclusion can be drawn about the toxicity of a specific nanomaterial for all plant species.

Graphene oxide exhibited positive effects on the growth of Aloe vera L

There is increasing evidence for graphene associated plant growth promotion, however, the chronic effects of soil-applied graphene remain largely unexplored. The present study investigated the morphological, physiological and biochemical responses of graphene oxide (GO) on Aloe vera L. over the concentration range of 0-100 mg/L for four months. Our results demonstrated that GO, with the best efficiency at 50 mg/L, could enhance the photosynthetic capacity of leaves, increase the yield and morphological characters of root and leaf, improve the nutrient (protein and amino acid) contents of leaf, without reducing the content of the main bioactive compound aloin. Compared with leaves, the effect of GO on root growth was more obvious. Although the electrolyte leakage and MDA content were raised at high concentrations, GO treatment did not increase the root antioxidant enzymes activity or decrease the root vigor, which excluding typical stress response. Furthermore, injection experiments showed that the GO in vivo did not change the plant growth state obviously. Taken together, our study revealed the role of GO in promoting Aloe vera growth by stimulating root growth and photosynthesis, which would provide theory basis for GO application in agriculture and forestry.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-021-00979-3.

Influence of graphene on the multiple metabolic pathways of Zea mays roots based on transcriptome analysis

Graphene reportedly exerts positive effects on plant root growth and development, although the corresponding molecular response mechanism remains to be elucidated. Maize seeds were randomly divided into a control and experimental group, and the roots of Zea mays L. seedlings were watered with different concentrations (0-100 mg/L) of graphene to explore the effects and molecular mechanism of graphene on the growth and development of Z. mays L. Upon evaluating root growth indices, 50 mg/L graphene remarkably increased total root length, root volume, and the number of root tips and forks of maize seedlings compared to those of the control group. We observed that the contents of nitrogen and potassium in rhizosphere soil increased following the 50 mg/L graphene treatment. Thereafter, we compared the transcriptome changes in Z. mays roots in response to the 50 mg/L graphene treatment. Transcriptional factor regulation, plant hormone signal transduction, nitrogen and potassium metabolism, as well as secondary metabolism in maize roots subjected to graphene treatment, exhibited significantly upregulated expression, all of which could be related to mechanisms underlying the response to graphene. Based on qPCR validations, we proposed several candidate genes that might have been affected with the graphene treatment of maize roots. The transcriptional profiles presented here provide a foundation for deciphering the mechanism underlying graphene and maize root interaction.

Nanoparticle-Based Sustainable Agriculture and Food Science: Recent Advances and Future Outlook

In the current scenario, it is an urgent requirement to satisfy the nutritional demands of the rapidly growing global population. Using conventional farming, nearly one third of crops get damaged, mainly due to pest infestation, microbial attacks, natural disasters, poor soil quality, and lesser nutrient availability. More innovative technologies are immediately required to overcome these issues. In this regard, nanotechnology has contributed to the agrotechnological revolution that has imminent potential to reform the resilient agricultural system while promising food security. Therefore, nanoparticles are becoming a new-age material to transform modern agricultural practices. The variety of nanoparticle-based formulations, including nano-sized pesticides, herbicides, fungicides, fertilizers, and sensors, have been widely investigated for plant health management and soil improvement. In-depth understanding of plant and nanomaterial interactions opens new avenues toward improving crop practices through increased properties such as disease resistance, crop yield, and nutrient utilization. In this review, we highlight the critical points to address current nanotechnology-based agricultural research that could benefit productivity and food security in future.

Guest Edited Collection: Nanotechnology in agriculture

Agriculture must overcome several challenges in order to increase—or even maintain—production, while also reducing negative environmental impact. Nanotechnology, fundamentally through the development of smart delivery systems and nanocarriers, can contribute to engineering more efficient and less contaminant agrochemicals. This Collection presents recent related works, covering nanodevices that improve crop protection against pests and diseases, nanoformulations for enhancing plant nutrition, and nanomaterials strengthening the general crop performance.