Nanoparticle Uptake in Plants: Gold Nanomaterial Localized in Roots of Arabidopsis thaliana by X-ray Computed Nanotomography and Hyperspectral Imaging

The role of iron materials in the abiotic transformation and biotransformation of polybrominated diphenyl ethers (PBDEs): A review

Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants, easily enter the environment, thus posing environmental and health risks. Iron materials play a key role during the migration and transformation of PBDEs. This article reviews the processes and mechanisms of adsorption, degradation, and biological uptake and transformation of PBDEs affected by iron materials in the environment. Iron materials can effectively adsorb PBDEs through hydrophobic interactions, π-π interactions, hydrogen/halogen bonds, electrostatic interactions, coordination interactions, and pore filling interactions. In addition, they are beneficial for the photodegradation, reduction debromination, and advanced oxidation degradation and debromination of PBDEs. The iron material-microorganism coupling technology affects the uptake and transformation of PBDEs. In addition, iron materials can reduce the uptake of PBDEs in plants, affecting their bioavailability. The species, concentration, and size of iron materials affect plant physiology. Overall, iron materials play a bidirectional role in the biological uptake and transformation of PBDEs. It is necessary to strengthen the positive role of iron materials in reducing the environmental and health risks caused by PBDEs. This article provides innovative ideas for the rational use of iron materials in controlling the migration and transformation of PBDEs in the environment.

Nanoparticle-mediated defense priming: A review of strategies for enhancing plant resilience against biotic and abiotic stresses

Nanotechnology has emerged as a promising field with the potential to revolutionize agriculture, particularly in enhancing plant defense mechanisms. Nanoparticles (NPs) are instrumental in plant defense priming, where plants are pre-exposed to controlled levels of stress to heighten their alertness and responsiveness to subsequent stressors. This process improves overall plant performance by enabling quicker and more effective responses to secondary stimuli. This review explores the application of NPs as priming agents, utilizing their unique physicochemical properties to bolster plants' innate defense mechanisms. It discusses key findings in NP-based plant defense priming, including various NP types such as metallic, metal oxide, and carbon-based NPs. The review also investigates the intricate mechanisms by which NPs interact with plants, including uptake, translocation, and their effects on plant physiology, morphology, and molecular processes. Additionally, the review examines how NPs can enhance plant responses to a range of stressors, from pathogen attacks and herbivore infestations to environmental stresses. It also discusses NPs' ability to improve plants' tolerance to abiotic stresses like drought, salinity, and heavy metals. Safety and regulatory aspects of NP use in agriculture are thoroughly addressed, emphasizing responsible and ethical deployment for environmental and human health safety. By harnessing the potential of NPs, this approach shows promise in reducing crop losses, increasing yields, and enhancing global food security while minimizing the environmental impact of traditional agricultural practices. The review concludes by emphasizing the importance of ongoing research to optimize NP formulations, dosages, and delivery methods for practical application in diverse agricultural settings.

Plant-nano interactions: A new insight of nano-phytotoxicity

Whether nanoparticles (NPs) are boon or bane for society has been a centre of in-depth debate and key consideration in recent times. Exclusive physicochemical properties like small size, large surface area-to-volume ratio, robust catalytic activity, immense surface energy, magnetism and superior biocompatibility make NPs obligatory in many scientific, biomedical and industrial ventures. Nano-enabled products are newer entrants in the present era. To attenuate environmental stress and maximize crop yields, scientists are tempted to introduce NPs as augmented supplements in agriculture. The feasible approaches for NPs delivery are irrigation, foliar spraying or seed priming. Internalization of excessive NPs to plants endorses negative implications at higher trophic levels via biomagnification. The characteristics of NPs (dimensions, type, solubility, surface charge), applied concentration and duration of exposure are prime factors conferring nanotoxicity in plants. Several reports approved NPs persuaded toxicity can precisely mimic abiotic stress effects. The signature effects of nanotoxicity include poor root outgrowth, biomass reduction, oxidative stress evolution, lipid peroxidation, biomolecular damage, perturbed antioxidants, genotoxicity and nutrient imbalance in plants. NPs stress impels mitogen-activated protein kinase signaling cascade and urges stress responsive defence gene expression to counteract stress in plants. Exogenous supplementation of nitric oxide (NO), arbuscular mycorrhizal fungus (AMF), phytohormones, and melatonin (ME) is novel strategy to circumvent nanotoxicity. Briefly, this review appraises plants' physio-biochemical responses and adaptation scenarios to endure NPs stress. As NPs stress represents large-scale contaminants, advanced research is indispensable to avert indiscriminate NPs usage for synchronizing nano-security in multinational markets.

Facile engineering of aptamer-coupled silk fibroin encapsulated myogenic gold nanocomposites: investigation of antiproliferative activity and apoptosis induction

Nanocomposites selectively induce cancer cell death, holding potential for precise liver cancer treatment breakthroughs. This study assessed the cytotoxicity of gold nanocomposites (Au NCs) enclosed within silk fibroin (SF), aptamer (Ap), and the myogenic Talaromyces purpureogenus (TP) against a human liver cancer cell (HepG2). The ultimate product, Ap-SF-TP@Au NCs, results from a three-step process. This process involves the myogenic synthesis of TP@Au NCs derived from TP mycelial extract, encapsulation of SF on TP@Au NCs (SF-TP@Au NCs), and the conjugation of Ap within SF-TP@Au NCs. The synthesized NCs are analyzed by various characteristic techniques. Ap-SF-TP@Au NCs induced potential cell death in HepG2 cells but exhibited no cytotoxicity in non-cancerous cells (NIH3T3). The morphological changes in cells were examined through various biochemical staining methods. Thus, Ap-SF-TP@Au NCs emerge as a promising nanocomposite for treating diverse cancer cells.

Comprehensive framework for overcoming scientific challenges related to assessing radioactive ultra-fine (nano/micro) particles transfer at the atmosphere-leaf interface

Food products are prone into contamination after a nuclear emission of radionuclides. While the mechanisms of emission and deposition of ultrafine radioactive particles are well documented, the transfer of these species from the atmosphere into plants is poorly assessed. This is evident in the lack of quantification of particles distributed within plants, especially regarding particles physical-chemical criteria to plant of different properties. Such knowledge gaps raise the concern about the representativeness of risk assessment tools designed for the transfer evaluation of ionic/soluble species to be qualified for simulating insoluble species exposure and proposes a possible underestimation. This highlights the possible need for special particle codes development to be implemented in models for future emissions. In addition, the later tools utilize transfer factors aggregating relevant sub-processes, suggesting another weak point in their overall reliability. As researchers specialized in the nuclear safety and protection, we intend in this perspective, to develop a compressive analysis of the interaction of ultrafine particles with plants of different specificities at different level processes starting from particles retention and gradual translocation to sink organs. This analysis is leveraged in providing insights for possible improvements in the current modeling tools for better real-life scenarios representation.

Critical Review: Uptake and Translocation of Organic Nanodelivery Vehicles in Plants

Nanodelivery vehicles (NDVs) are engineered nanomaterials (ENMs) that, within the agricultural sector, have been investigated for their ability to improve uptake and translocation of agrochemicals, control release, or target specific tissues or subcellular compartments. Both inorganic and organic NDVs have been studied for agrochemical delivery in the literature, but research on the latter has been slower to develop than the literature on the former. Since the two classes of nanomaterials exhibit significant differences in surface chemistry, physical deformability, and even colloidal stability, trends that apply to inorganic NDVs may not hold for organic NDVs, and vice versa. We here review the current literature on the uptake, translocation, biotransformation, and cellular and subcellular internalization of organic NDVs in plants following foliar or root administration. A background on nanomaterials and plant physiology is provided as a leveling ground for researchers in the field. Trends in uptake and translocation are examined as a function of NDV properties and compared to those reported for inorganic nanomaterials. Methods for assessing fate and transport of organic NDVs in plants (a major bottleneck in the field) are discussed. We end by identifying knowledge gaps in the literature that must be understood in order to rationally design organic NDVs for precision agrochemical nanodelivery.

Border cell population size and oxidative stress in the root apex of Triticum aestivum seedlings exposed to fungicides

Fungicides reduce the risk of mycopathologies and reduce the content of mycotoxins in commercial grain. The effect of fungicides on the structural and functional status of the root system of grain crops has not been studied enough. In this regard, we studied the phytocytotoxic effects tebuconazole (TEB) and epoxiconazole (EPO) and azoxystrobin (AZO) in the roots of Triticum aestivum seedlings in hydroponic culture. In the presence of EPO and AZO (but not TEB) inhibition of the root growth was accompanied by a dose-dependent increase in the content of malondialdehyde, carbonylated proteins, and proline in roots. TEB was characterized by a dose-dependent decrease in the total amount of border cells (BCs) and the protein content in root extracellular trap (RET). For EPO and AZO, the dose curves of changes in the total number of BCs were bell-shaped. AZO did not affect the protein content in RET. The protein content in RET significantly decreased by 3 times for an EPO concentration of 1 µg/mL. The obtained results reveal that the BC-RET system is one of the functional targets of fungicides in the root system of wheat seedlings. Studied fungicides induce oxidative stress and structural and functional alterations in the BC-RET system that can affect their toxicity to the root system of crops.

Silicon nanoparticles in sustainable agriculture: synthesis, absorption, and plant stress alleviation

Silicon (Si) is a widely recognized beneficial element in plants. With the emergence of nanotechnology in agriculture, silicon nanoparticles (SiNPs) demonstrate promising applicability in sustainable agriculture. Particularly, the application of SiNPs has proven to be a high-efficiency and cost-effective strategy for protecting plant against various biotic and abiotic stresses such as insect pests, pathogen diseases, metal stress, drought stress, and salt stress. To date, rapid progress has been made in unveiling the multiple functions and related mechanisms of SiNPs in promoting the sustainability of agricultural production in the recent decade, while a comprehensive summary is still lacking. Here, the review provides an up-to-date overview of the synthesis, uptake and translocation, and application of SiNPs in alleviating stresses aiming for the reasonable usage of SiNPs in nano-enabled agriculture. The major points are listed as following: (1) SiNPs can be synthesized by using physical, chemical, and biological (green synthesis) approaches, while green synthesis using agricultural wastes as raw materials is more suitable for large-scale production and recycling agriculture. (2) The uptake and translocation of SiNPs in plants differs significantly from that of Si, which is determined by plant factors and the properties of SiNPs. (3) Under stressful conditions, SiNPs can regulate plant stress acclimation at morphological, physiological, and molecular levels as growth stimulator; as well as deliver pesticides and plant growth regulating chemicals as nanocarrier, thereby enhancing plant growth and yield. (4) Several key issues deserve further investigation including effective approaches of SiNPs synthesis and modification, molecular basis of SiNPs-induced plant stress resistance, and systematic effects of SiNPs on agricultural ecosystem.

Pemetrexed loaded gold nanoparticles as cytotoxic and apoptosis inducers in lung cancer cells through ROS generation and mitochondrial dysfunction pathway

Supramolecular nanoparticles containing peptides and drugs have recently gained recognition as an effective tumor treatment drug delivery system. A multitarget drug termed pemetrexed is effective against various cancers, including nonsmall cell lung cancer. The work aims to establish the capability of pemetrexed gold nanoparticles (PEM-AuNPs) to induce apoptosis and explore molecular changes. X-ray diffraction, Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscope, and transmission electron microscope were used to investigate the synthesized nanoparticles. The MTT assay was utilized to investigate the anticancer properties of PEM-AuNPs at varying concentrations (50, 100, and 200 µM). PEM-AuNPs demonstrated a decrease in cell viability with 55.87%, 43.04%, and 25.59% for A549 cells and 54.31%, 37.40%, and 25.84% for H1299 cells at the respective concentrations. To assess apoptosis and perform morphological analysis, diverse biochemical staining techniques, including acridine orange-ethidium bromide and 4',6-diamidino-2-phenylindole nuclear staining assays, were employed. Additionally, 2',7'-dichlorofluorescein diacetate staining confirmed the induction of reactive oxygen species generation, while JC-1 staining validated the impact on the mitochondrial membrane at the IC50 concentration of PEM-AuNPs. Thus, the study demonstrated that the synthesized  PEM-AuNPs exhibited enhanced anticancer activity against both A549 and H1299 cells.

Proteomic insights to decipher nanoparticle uptake, translocation, and intercellular mechanisms in plants

Advent of proteomic techniques has made it possible to identify a broad spectrum of proteins in living systems. Studying the impact of nanoparticle (NP)-mediated plant protein responses is an emerging field. NPs are continuously being released into the environment and directly or indirectly affect plant's biochemistry. Exposure of plants to NPs, especially crops, poses a significant risk to the food chain, leading to changes in underlying metabolic processes. Once absorbed by plants, NPs interact with cellular proteins, thereby inducing changes in plant protein patterns. Based on the reactivity, properties, and translocation of nanoparticles, NPs can interfere with proteins involved in various cellular processes in plants such as energy regulation, redox metabolism, and cytotoxicity. Such interactions of NPs at the subcellular level enhance ROS scavenging activity, especially under stress conditions. Although higher concentrations of NPs induce ROS production and hinder oxidative mechanisms under stress conditions, NPs also mediate metabolic changes from fermentation to normal cellular processes. Although there has been lots of work conducted to understand the different effects of NPs on plants, the knowledge of proteomic responses of plants toward NPs is still very limited. This review has focused on the multi-omic analysis of NP interaction mechanisms with crop plants mainly centering on the proteomic perspective in response to both stress and non-stressed conditions. Furthermore, NP-specific interaction mechanisms with the biological pathways are discussed in detail.

Quantification of nanoplastic uptake and distribution in the root, stem and leaves of the edible herb Lepidum sativum

This study confirms the uptake, translocation and bioaccumulation of 100 nm polystyrene nanoplastics in the root, stem and leaves of the plant Lepidum sativum at exposure concentrations ranging from environmentally realistic 10 μg/L up to a high of 100 mg/L. Accumulation in plant tissues was characterised by aggregation in the intercellular spaces and heterogeneous distribution. Nanoplastic presence was confirmed in the root tips, root surface and stele, lateral roots, root hairs, stem vascular bundles, leaf veins and mesophyll, as well as leaf epidermis including stomatal sites. Quantification results show that majority of the particles were retained in the root and accumulation in stem and leaves was only 13 to 18 % of the median value in roots. There was a reduction of 38.89 ± 9.62 % in the germination rate, 55 % in plant fresh weight, as well as in root weight (> 80 %), root length (> 60 %), shoot weight (51 to 78 %) and number of lateral roots (> 28 %) at exposure concentrations at and above 50 mg/L. However, lower, environmentally probable exposure concentrations did not affect the plant health significantly. Our results highlight the urgent need for further exploration of this issue from the point of view of food safety and security. STATEMENT OF ENVIRONMENTAL IMPLICATION: Micro and nanoplastics have been reported in agricultural environments across the globe and reports regarding their hazardous effects over agricultural and plant health call for an urgent exploration of this issue. This work demonstrates the uptake, bioaccumulation and distribution of nanoplastics in an edible plant at an environmentally realistic concentration and raises serious concerns regarding the possible implications for food safety and security. It presents a novel approach which addresses the quantification of nanoplastic accumulation in plant tissues and helps identify the mechanism and trends behind this phenomenon which has been a challenge up until now.

Insights into the effect of manganese-based nanomaterials on the distribution trait and nutrition of radish (Raphanus sativus L.)

Manganese (Mn) is one of the essential elements for plant growth and is involved in the process of photosynthesis and seed germination. Herein, we applied two Mn-based nanoparticles, MnO2 and Mn3O4, to the soil to investigate their effects on radish growth, antioxidant system, and nutrients. The radish plant height after treatment with 10 mg/kg of MnO2 and Mn3O4 NPs were increased, compare to the control. In radish's shoot, MnO2 NPs at high concentrations (100 mg/kg) increased MDA activity by 58 % compared to the control group, while exposure to Mn3O4 NPs at the same concentration decreased MDA activity by 14 %. The nutrient content of radishes, such as soluble sugar and vitamin C, was improved. Moreover, single particle inductively coupled plasma mass spectrometry (SP ICP-MS) was used to understand the patterns of migration of Mn-based NPs in radish and subsequent impact on nutrients. We found that Mn-based NPs accumulated mainly in the roots of radish. Interestingly, the accumulation characteristics of MnO2 NPs and Mn3O4 NPs were different. MnO2 NPs accumulated more in radish leaves than in fruits, while the accumulation of Mn3O4 NPs gradually decreased from roots to leaves. Finally, we determined the mineral element content of the leaves, fruits, and roots of radish, and found that the uptake of main metallic mineral elements (e.g. Cu, Fe, Mg, Zn, Na, K) was inhibited by the application of Mn-based NPs. These findings underscore the importance of considering species and multifaceted impacts of Mn-based NPs as nanofertilizers for their wide application in agriculture.

Transport of Nanoparticles into Plants and Their Detection Methods

Nanoparticle transport into plants is an evolving field of research with diverse applications in agriculture and biotechnology. This article provides an overview of the challenges and prospects associated with the transport of nanoparticles in plants, focusing on delivery methods and the detection of nanoparticles within plant tissues. Passive and assisted delivery methods, including the use of roots and leaves as introduction sites, are discussed, along with their respective advantages and limitations. The barriers encountered in nanoparticle delivery to plants are highlighted, emphasizing the need for innovative approaches (e.g., the stem as a new recognition site) to optimize transport efficiency. In recent years, research efforts have intensified, leading to an evendeeper understanding of the intricate mechanisms governing the interaction of nanomaterials with plant tissues and cells. Investigations into the uptake pathways and translocation mechanisms within plants have revealed nuanced responses to different types of nanoparticles. Additionally, this article delves into the importance of detection methods for studying nanoparticle localization and quantification within plant tissues. Various techniques are presented as valuable tools for comprehensively understanding nanoparticle-plant interactions. The reliance on multiple detection methods for data validation is emphasized to enhance the reliability of the research findings. The future outlooks of this field are explored, including the potential use of alternative introduction sites, such as stems, and the continued development of nanoparticle formulations that improve adhesion and penetration. By addressing these challenges and fostering multidisciplinary research, the field of nanoparticle transport in plants is poised to make significant contributions to sustainable agriculture and environmental management.

The threat of micro/nanoplastic to aquatic plants: current knowledge, gaps, and future perspectives

Plastics have been recognized as an emerging pollutant and have raised global concerns due to their widespread distribution in the environment and potential harm to living systems. However, research on the threat of micro/nanoplastics (MPs/NPs) to the unique group of aquatic plants is far behind, necessitating a comprehensive review to summarize current research progress and identify future research needs. This review explores the sources and distribution patterns of MPs/NPs in aquatic environments, highlighting their uptake by aquatic plants through roots and leaves, and subsequent translocation via the vascular system facilitated by the transpiration stream. Exposure to MPs/NPs elicits diverse effects on the growth, physiology, and ecological interactions of aquatic plants, with variations influenced by plastic properties, plant species, and experimental conditions. Furthermore, the presence of MPs/NPs can impact the toxicity and bioavailability of other associated toxicants to aquatic plants. This review shows critical knowledge gaps and emphasizes the need for future research to bridge the current understanding of the limitations and challenges posed by MPs/NPs in aquatic ecosystems.

Micro (nano) plastics uptake, toxicity and detoxification in plants: Challenges and prospects

Plastic pollution has emerged as a global challenge affecting ecosystem health and biodiversity conservation. Terrestrial environments exhibit significantly higher plastic concentrations compared to aquatic systems. Micro/nano plastics (MNPs) have the potential to disrupt soil biology, alter soil properties, and influence soil-borne pathogens and roundworms. However, limited research has explored the presence and impact of MNPs on aquaculture systems. MNPs have been found to inhibit plant and seedling growth and affect gene expression, leading to cytogenotoxicity through increased oxygen radical production. The article discusses the potential phytotoxicity process caused by large-scale microplastics, particularly those unable to penetrate cell pores. It also examines the available data, albeit limited, to assess the potential risks to human health through plant uptake.

Impacts of Micro(nano)plastics on Terrestrial Plants: Germination, Growth, and Litter

Micro(nano)plastics (MNP) are pervasive in various environmental media and pose a global environmental pollution issue, particularly in terrestrial ecosystems, where they exert a significant impact on plant growth and development. This paper builds upon prior research to analyze and consolidate the effects of MNP on soil properties, seed germination, plant growth, and litter decomposition. The objective is to elucidate the environmental behavior of MNP and their mechanisms of influence on the plant life cycle. The unique physicochemical and electrical properties of MNP enable them to modify soil structure, water retention capacity, and pH. They can potentially act as "electron shuttles" or disrupt natural "electron shuttles" in litter decomposition, thereby interfering with nutrient transport and availability in the soil. Furthermore, MNP can physically obstruct nutrient and water channels within plants, impacting nutrient and water absorption. Once infiltrating plant tissues, MNP can form eco-coronas with plant proteins. Together with MNP adsorbed on the plant's surface and within its tissues, they disrupt normal physiological processes, leading to changes in photosynthesis, biomass, cellular toxicity, genetics, nutrient uptake, and gene expression. These changes, in turn, influence seed germination and plant growth and development. As a burgeoning research field, future studies should delve deeper into various aspects of these changes, such as elucidating the pathways and mechanisms through which MNP enter plant tissues, assessing their intensity and mechanisms of toxicity on different plant species, and exploring the relationship between micro(nano)plastics and "electron shuttles". These endeavors will contribute to establishing a more comprehensive theoretical framework for understanding the environmental behavior of MNP and their impact on plants.

Alleviation of chromium stress in plants using metal and metal oxide nanoparticles

Chromium (Cr), one of the hazardous pollutants, exists predominantly as Cr(VI) and Cr(III) in the environment. Cr(VI) is more toxic than Cr(III) due to its high mobility and solubility. Elevated levels of Cr in agricultural soil due to various anthropogenic activities cause Cr accumulation in plants, resulting in a significant reduction in plant yield and quality due to Cr-induced physiological, biochemical and molecular alterations. It can infiltrate the food chain through crop plants and cause harmful effects in humans via biomagnification. Cr(VI) is linked to cancer in humans. Therefore, mitigation strategies are required to remediate Cr-polluted soils and limit its accumulation in plants for safe food production. Recent research on metal and metal oxide nanoparticles (NPs) has shown that they can effectively reduce Cr accumulation and phytotoxicity. The effects of these NPs are influenced by their type and dose, exposure method, plant species and experimental settings. In this review, we present an up-to-date compilation and comprehensive analysis of the existing literature regarding the process of uptake and distribution of Cr and impact and potential mechanisms of metal and metal oxide nanoparticles led mitigation of Cr-induced stress in plants. We have also discussed recent developments, existing research gaps and future research directions in the field of Cr stress mitigation by NPs in plants. Overall, this review can provide valuable insights in reducing Cr accumulation and toxicity using metal and metal oxide nanoparticles, thereby promoting safe and sustainable cultivation of food and phytostabilization of Cr-polluted soil.

An unrecognized entry pathway of submicrometre plastics into crop root: The split of hole in protective layer

Threats to food safety caused by the continuous accumulation of plastic particles in the terrestrial environment is currently a worldwide concern. To date, descriptions of how plastic particles pass the external biological barrier of crop root have been vague. Here, we demonstrated that submicrometre polystyrene particles passed unimpededly the external biological barrier of maize through the split of holes in the protective layer. We identified plastic particles induced the apical epidermal cells of root tips become round, thereby expanding the intercellular space. It further pulled apart the protective layer between the epidermal cells, and eventually formed the entry pathway for plastic particles. The enhancement of oxidative stress level induced by plastic particles was the main reason for the deformation of the apical epidermal cells (increased roundness values: 15.5%), comparing to the control. Our findings further indicated that the presence of cadmium was conducive to the "holes" formation. Our results highlighted the critical insights into the fracture mechanisms of plastic particles for the external biological barriers of crop roots, providing a strong incentive to access the risk of plastic particles in agriculture security.

Visual tracking of label-free microplastics in wheat seedlings and their effects on crop growth and physiology

The effects of microplastics on crop plants have attracted growing attention. However, little is known about the effects of microplastics and their extracts on the growth and physiology of wheat seedlings. In this study, hyperspectral-enhanced dark field microscopy and scanning electron microscopy were used to accurately track the accumulation of 200 nm label-free polystyrene microplastics (PS) in wheat seedlings. The PS accumulated along the root xylem cell wall and in the xylem vessel member and then moved toward to the shoots. In addition, lower concentration (≤ 5 mg·L^-1) of microplastics increased root hydraulic conductivity by 80.6 %- 117.0 %. While higher PS treatment (200 mg·L^-1) considerably decreased plant pigments content (chlorophyll a, b, and total chlorophyll) by 14.8 %, 19.9 %, and 17.2 %, respectively, and decreased root hydraulic conductivity by 50.7 %. Similarly, catalase activity was reduced by 17.7 % in root and 36.8 % in shoot. However, extracts from the PS solution showed no physiological effect on wheat. The result confirmed that it was the plastic particle, rather than the chemical reagents added in the microplastics, contributed to the physiological variation. These data will benefit to better understanding on the behavior of microplastics in soil plants, and to providing of convincing evidence for the effects of terrestrial microplastics.

Silicon nanoparticles: Synthesis, uptake and their role in mitigation of biotic stress

In the current scenario of global warming and climate change, plants face many biotic stresses, which restrain growth, development and productivity. Nanotechnology is gaining precedence over other means to deal with biotic and abiotic constraints for sustainable agriculture. One of nature's most beneficial metalloids, silicon (Si) shows ameliorative effect against environmental challenges. Silicon/Silica nanoparticles (Si/SiO₂NPs) have gained special attention due to their significant chemical and optoelectronic capabilities. Its mesoporous nature, easy availability and least biological toxicity has made it very attractive to researchers. Si/SiO₂NPs can be synthesised by chemical, physical and biological methods and supplied to plants by foliar, soil, or seed priming. Upon uptake and translocation, Si/SiO₂NPs reach their destined cells and cause optimum growth, development and tolerance against environmental stresses as well as pest attack and pathogen infection. Using Si/SiO₂NPs as a supplement can be an eco-friendly and cost-effective option for sustainable agriculture as they facilitate the delivery of nutrients, assist plants to mitigate biotic stress and enhances plant resistance. This review aims to present an overview of the methods of formulation of Si/SiO₂NPs, their application, uptake, translocation and emphasize the role of Si/SiO₂NPs in boosting growth and development of plants as well as their conventional advantage as fertilizers with special consideration on their mitigating effects towards biotic stress.

Nanoparticles in Plants: Uptake, Transport and Physiological Activity in Leaf and Root

Due to their unique characteristics, nanoparticles are increasingly used in agricultural production through foliage spraying and soil application. The use of nanoparticles can improve the efficiency of agricultural chemicals and reduce the pollution caused by the use of agricultural chemicals. However, introducing nanoparticles into agricultural production may pose risks to the environment, food and even human health. Therefore, it is crucial to pay attention to the absorption migration, and transformation in crops, and to the interaction with higher plants and plant toxicity of nanoparticles in agriculture. Research shows that nanoparticles can be absorbed by plants and have an impact on plant physiological activities, but the absorption and transport mechanism of nanoparticles is still unclear. This paper summarizes the research progress of the absorption and transportation of nanoparticles in plants, especially the effect of size, surface charge and chemical composition of nanoparticle on the absorption and transportation in leaf and root through different ways. This paper also reviews the impact of nanoparticles on plant physiological activity. The content of the paper is helpful to guide the rational application of nanoparticles in agricultural production and ensure the sustainability of nanoparticles in agricultural production.

Plasmonic nanorod probes' journey inside plant cells for in vivo SERS sensing and multimodal imaging

Nanoparticle-based platforms are gaining strong interest in plant biology and bioenergy research to monitor and control biological processes in whole plants. However, in vivo monitoring of biomolecules using nanoparticles inside plant cells remains challenging due to the impenetrability of the plant cell wall to nanoparticles beyond the exclusion limits (5-20 nm). To overcome this physical barrier, we have designed unique bimetallic silver-coated gold nanorods (AuNR@Ag) capable of entering plant cells, while conserving key plasmonic properties in the near-infrared (NIR). To demonstrate cellular internalization and tracking of the nanorods inside plant tissue, we used a comprehensive multimodal imaging approach that included transmission electron microscopy (TEM), confocal fluorescence microscopy, two-photon luminescence (TPL), X-ray fluorescence microscopy (XRF), and photoacoustics imaging (PAI). We successfully acquired SERS signals of nanorods in vivo inside plant cells of tobacco leaves. On the same leaf samples, we applied orthogonal imaging methods, TPL and PAI techniques for in vivo imaging of the nanorods. This study first demonstrates the intracellular internalization of AuNR@Ag inside whole plant systems for in vivo SERS analysis in tobacco cells. This work demonstrates the potential of this nanoplatform as a new nanotool for intracellular in vivo biosensing for plant biology.

Accumulation, translocation, and transformation of two CdSe/ZnS quantum dots in rice and pumpkin plants

As a widely applied semiconductor nanomaterial, quantum dots (QDs) have drawn considerable interest. In this study, pumpkin and rice seedlings were hydroponically exposed to two core/shell CdSe/ZnS QDs coated with cysteamine (CdSe/ZnS-CA) and polyethylene glycol-carboxy (CdSe/ZnS-PEG-COOH) for 10 days to analyze their time-varying uptake, translocation, and transformation behaviors in plants. Both QDs were mainly adsorbed/absorbed by the roots in the particulate state, and more CdSe/ZnS-CA accumulated than CdSe/ZnS-PEG-COOH. For CdSe/ZnS-CA-treated plants, the Se and Cd concentrations (CSe and CCd) associated with the roots were 561 ± 75 and 580 ± 73 μg/g (dw) for rice and 474 ± 49 and 546 ± 53 μg/g (dw) for pumpkin, respectively, on day 10. For CdSe/ZnS-PEG-COOH-treated plants, the concentrations of Se and Cd associated with roots were 392 ± 56 and 453 ± 56 μg/g (dw) for rice and 363 ± 52 and 417 ± 52 μg/g (dw) for pumpkin, respectively. The surface charges and coatings significantly affected the accumulation of QDs at the beginning of exposure; however, the impaction decreased with time. The ratios between the Cd and Se concentrations (CCd/CSe) in the stems and leaves varied from those of the QD standards, indicating the transformation of the QDs in the exposure system. Se and Cd were more likely to translocate in CdSe/ZnS-PEG-COOH-treated plants than in CdSe/ZnS-CA-treated plants. The vertical translocation of Se was greater than that of Cd. Rice showed greater abilities of accumulation and translocation of Se and Cd from both QDs than pumpkin. These findings improve our understanding of the interference of QDs with plants and their environmental fate.

Synthesis of Nickel-Chitosan Nanoparticles for Controlling Blast Diseases in Asian Rice

Rice blast caused by Pyricularia oryzae is one of most devastating fungal diseases in rice, reducing the annual yield of rice worldwide. As an alternative to fungicide for curbing rice blast, synthesis of nickel-chitosan nanoparticles (Ni-Ch NPs) was performed with nickel chloride and assessed its efficacy in inflating plant growth and hindrance of Pyricularia oryzae (blast pathogen). Characterization of Ni-Ch NPs from SEM, TEM, and DLS analyses showed smooth- and spherical-shaped nanoparticles in the range of 20-70 nm. Colloidal stability of NPs was revealed from Zeta potential exhibiting polydispersity index of 0.22. EDX spectroscopy corroborated the presence of nickel (14.05%) in synthesized Ni-Ch NPs. A significant increase in germination and growth attributes in terms of shoot and root length and number of lateral roots over control was observed in paddy seeds on the treatment with Ni-Ch NPs. Furthermore, the application of NPs in paddy plants under glasshouse condition demonstrated a remarkable improvement in plant growth. Protein profiling of NP-treated plants revealed new polypeptides (Rubisco units) enlightening the enhanced photosynthetic rate. Also, Asian rice exhibited reduced blast symptoms on leaves treated with NPs under glasshouse condition while displaying 64% mycelia inhibition in Petri plates. All these results suggest that nickel-chitosan nanoparticles could be exploited as an effective plant growth promoter cohort in controlling rice blast disease.

A high-resolution study of PM2.5 accumulation inside leaves in leaf stomata compared with non-stomatal areas using three-dimensional X-ray microscopy

Plant leaves retain atmospheric particulate matter (PM) on their surfaces, helping PM removal and risk reduction of respiratory tract infection. Several processes (deposition, resuspension, rainfall removal) can influence the PM accumulation on leaves and different leaf microstructures (e.g., trichomes, epicuticular waxes) can also be involved in retaining PM. However, the accumulation and distribution of PM on leaves, particularly at the stomata, are unclear, and the lack of characterization methods limits our understanding of this process. Thus, in this study, we aimed to explore the pathway through which PM_2.5 (aerodynamic diameter ≤ 2.5 μm) enters plant leaves, and the penetration depth of PM_2.5 along the entry route. Here, an indoor experiment using diamond powder as a tracer to simulate PM_2.5 deposition on leaves was carried out. Then, the treated and non-treated leaves were scanned by using three-dimensional (3D) X-ray microscopy. Next, the grayscale value of the scanned images was used to compare PM_2.5 accumulation in stomatal and non-stomatal areas of the treated and non-treated leaves, respectively. Finally, a total PM_2.5 volume from the abaxial epidermis was calculated. The results showed that, first, a large amount of PM_2.5 accumulates within leaf stomata, whereas PM_2.5 does not accumulate at non-stomatal areas. Then, the penetration depth of PM_2.5 in stomata of most tree species was 5-14 μm from the abaxial epidermis. For the first time, 3D X-ray microscope scanning was used to confirm that a pathway by which PM_2.5 enters the leaves is through the stomata, which is fundamental for further research on how PM_2.5 translocates and interacts with tissues and cells in leaves.

Effect of zinc and iron oxide nanoparticles on plant physiology, seed quality and microbial community structure in a rice-soil-microbial ecosystem

In this study, we assessed the impact of zinc oxide (ZnO) and iron oxide (FeO) (<36 nm) nanoparticles (NPs) as well as their sulphate salt (bulk) counterpart (0, 25, 100 mg/kg) on rice growth and seed quality as well as the microbial community in the rhizosphere environment of rice. During the rice growing season 2021-22, all experiments were conducted in a greenhouse (temperature: day 30 °C; night 20 °C; relative humidity: 70%; light period: 16 h/8 h, day/night) in rice field soil. Results showed that low concentrations of FeO and ZnO NPs (25 mg/kg) promoted rice growth (height (29%, 16%), pigment content (2%, 3%)) and grain quality parameters such as grains per spike (8%, 9%), dry weight of grains (12%, 14%) respectively. As compared to the control group, the Zn (2%) and Fe (5%) accumulations at their respective low concentrations of NP treatments showed stimulation. Interestingly, our results showed that at low concentration of both the NPs the soil microbes had more diversity and richness than those in the bulk treated and control soil group. Although a number of phyla were affected by the presence of NPs, the strongest effects were observed for change in the abundance of the three phyla for Proteobacteria, Actinobacteria, and Planctomycetes. The rhizosphere environment was notably enriched with potential streptomycin producers, carbon and nitrogen fixers, and lignin degraders with regard to functional groups of microorganisms. However, microbial communities mainly responsible for chitin degradation, ammonia oxidation, and nitrite reduction were found to be decreased. The results from this study highlight significant changes in several plant-based endpoints, as well as the rhizosphere soil microorganisms. It further adds information to our understanding of the nanoscale-specific impacts of important micronutrient oxides on both rice and its associated soil microbiome.

Nanoparticle's uptake and translocation mechanisms in plants via seed priming, foliar treatment, and root exposure: a review

Nanotechnology is one of the promising techniques and shares wide ranges of applications almost in every field of life. Nanomaterials are getting continuous attractions due to specific physical and chemical properties and being applied as multifunctional material. The use of nanomaterials/nanoparticles in agriculture sector for crop improvement and protection against various environmental threats have attained greater significance. Size and nature of nanoparticles, mode of application, environmental conditions, rhizospheric and phyllospheric environment, and plant species are major factors that influence the action of nanoparticles. The mode or method of nanoparticle applications to plants is attaining greater attentions. Recently, different methods for nanoparticle applications (seed priming, foliar, and root application) are being used to improve crop growth. It is of quite worth that which method is suitable for nanoparticle application, and how nanoparticles can possibly translocate to various plant tissues from root to shoot or vice versa. These information's are poorly understood and need more investigations to explore the comprehensive mechanism by which nanoparticles make their possible entry through different plant organs and how they transport to regulate various physiological and molecular functions in plant cells. Therefore, this study comprehensively provides the knowledge of nanoparticles uptake via seed priming, foliar exposure, and root application, and their possible translocation mechanism within plants influenced by various factors that has not clearly presented. This study will provide new insights to find out an actual uptake and translocation mechanism of nanoparticles that may help researchers to develop nanoparticle-based new strategies for plants to cope with various environmental challenges. This study also focuses on different soil factors or above ground factors that are involved in nanoparticles uptake and translocation and ultimately their functioning in plants.

Nano-enabled agriculture: How do nanoparticles cross barriers in plants?

Nano-enabled agriculture is a topic of intense research interest. However, our knowledge of how nanoparticles enter plants, plant cells, and organelles is still insufficient. Here, we discuss the barriers that limit the efficient delivery of nanoparticles at the whole-plant and single-cell levels. Some commonly overlooked factors, such as light conditions and surface tension of applied nano-formulations, are discussed. Knowledge gaps regarding plant cell uptake of nanoparticles, such as the effect of electrochemical gradients across organelle membranes on nanoparticle delivery, are analyzed and discussed. The importance of controlling factors such as size, charge, stability, and dispersibility when properly designing nanomaterials for plants is outlined. We mainly focus on understanding how nanoparticles travel across barriers in plants and plant cells and the major factors that limit the efficient delivery of nanoparticles, promoting a better understanding of nanoparticle-plant interactions. We also provide suggestions on the design of nanomaterials for nano-enabled agriculture.

Interplay of plastic pollution with algae and plants: hidden danger or a blessing?

In the era of plastic pollution, plants have been discarded as a system that is not affected by micro and nanoplastics, but contrary to beliefs that plants cannot absorb plastic particles, recent research proved otherwise. The presented review gives insight into known aspects of plants' interplay with plastics and how plants' ability to absorb plastic particles can be utilized to remove plastics from water and soil systems. Microplastics usually cannot be absorbed by plant root systems due to their size, but some reports indicate they might enter plant tissues through stomata. On the other hand, nanoparticles can enter plant root systems, and reports of their transport via xylem to upper plant parts have been recorded. Bioaccumulation of nanoplastics in upper plant parts is still not confirmed. The prospects of using biosystems for the remediation of soils contaminated with plastics are still unknown. However, algae could be used to degrade plastic particles in water systems through enzyme facilitated degradation processes. Considering the amount of plastic pollution, especially in the oceans, further research is necessary on the utilization of algae in plastic degradation. Special attention should be given to the research concerning utilization of algae with restricted algal growth, ensuring that a different problem is not induced, "sea blooming", during the degradation of plastics.

Root Hair Apex is the Key Site for Symplastic Delivery of Graphene into Plants

Uptake kinetics and delivery mechanisms of nanoparticles (NPs) in crop plants need to be urgently understood for the application of nanotechnology in agriculture as delivery systems for eco-friendly nanoagrochemicals. Here, we investigated the uptake kinetics, translocation pathway, and key internalization process of graphene in wheat (Triticum aestivum L.) by applying three specific hydroponic cultivation methods (submerging, hanging, and split-root). Quantification results on the uptake of carbon-14 radiolabeled graphene in each tissue indicated that graphene could enter the root of wheat and further translocate to the shoot with a low delivery rate (<2%). Transmission electron microscopy (TEM) images showed that internalized graphene was transported to adjacent cells through the plasmodesmata, clearly indicating the symplastic pathway of graphene translocation. The key site for the introduction of graphene into root cells for translocation through the symplastic pathway is evidenced to be the apex of growing root hair, where the newly constructed primary cell wall is much thinner. The confirmation of uptake kinetics and delivery mechanisms is useful for the development of nanotechnology in sustainable agriculture, especially for graphene serving as the delivery vector for pesticides, genes, and sensors.

Overview on Recent Developments in the Design, Application, and Impacts of Nanofertilizers in Agriculture

Nutrient management is always a great concern for better crop production. The optimized use of nutrients plays a key role in sustainable crop production, which is a major global challenge as it depends mainly on synthetic fertilizers. A novel fertilizer approach is required that can boost agricultural system production while being more ecologically friendly than synthetic fertilizers. As nanotechnology has left no field untouched, including agriculture, by its scientific innovations. The use of nanofertilizers in agriculture is in the early stage of development, but they appear to have significant potential in different ways, such as increased nutrient-use efficiency, the slow release of nutrients to prevent nutrient loss, targeted delivery, improved abiotic stress tolerance, etc. This review summarizes the current knowledge on various developments in the design and formulation of nanoparticles used as nanofertilizers, their types, their mode of application, and their potential impacts on agricultural crops. The main emphasis is given on the potential benefits of nanofertilizers, and we highlight the current limitations and future challenges related to the wide-scale application before field applications. In particular, the unprecedent release of these nanomaterials into the environment may jeopardize human health and the ecosystem. As the green revolution has occurred, the production of food grains has increased at the cost of the disproportionate use of synthetic fertilizers and pesticides, which have severely damaged our ecosystem. We need to make sure that the use of these nanofertilizers reduces environmental damage, rather than increasing it. Therefore, future studies should also check the environmental risks associated with these nanofertilizers, if there are any; moreover, it should focus on green manufactured and biosynthesized nanofertilizers, as well as their safety, bioavailability, and toxicity issues, to safeguard their application for sustainable agriculture environments.

Recent Advances in Metal-Based Nanoparticle-Mediated Biological Effects in Arabidopsis thaliana: A Mini Review

The widespread application of metal-based nanoparticles (MNPs) has prompted great interest in nano-biosafety. Consequently, as more and more MNPs are released into the environment and eventually sink into the soil, plants, as an essential component of the ecosystem, are at greater risk of exposure and response to these MNPs. Therefore, to understand the potential impact of nanoparticles on the environment, their effects should be thoroughly investigated. Arabidopsis (Arabidopsis thaliana L.) is an ideal model plant for studying the impact of environmental stress on plants’ growth and development because the ways in which Arabidopsis adapt to these stresses resemble those of many plants, and therefore, conclusions obtained from these scientific studies have often been used as the universal reference for other plants. This study reviewed the main findings of present-day interactions between MNPs and Arabidopsis thaliana from plant internalization to phytotoxic effects to reveal the mechanisms by which nanomaterials affect plant growth and development. We also analyzed the remaining unsolved problems in this field and provide a perspective for future research directions.

Imaging plant tissues: advances and promising clearing practices

The study of the organ structure of plants and understanding their physiological complexity requires 3D imaging with subcellular resolution. Most plant organs are highly opaque to light, and their study under optical sectioning microscopes is therefore difficult. In animals, many protocols have been developed to make organs transparent to light using clearing protocols (CPs). By contrast, clearing plant tissues is challenging because of the presence of fibers and pigments. We describe progress in the development of plant CPs over the past 20 years through a modified taxonomy of CPs based on their physical and optical parameters that affect tissue properties. We also discuss successful approaches that combine CPs with new microscopy methods and their future applications in plant science research.

Assessing implications of nanoplastics exposure to plants with advanced nanometrology techniques

Despite the increasing attention given to the impacts of nanoplastics in terrestrial environments, there is limited data about the effects on plants, and the quantitative information on uptake. In the present study, wheat plants grown in hydroponics were exposed to Pd-doped nanoplastics. This allowed us to quantify nanoplastics uptake and translocation to the shoots. Visualization of nanoplastics in roots was performed with synchrotron micro X-ray fluorescence (µXRF). Nanoplastics accumulated on the root epidermis, especially at the root tip and in root maturation zones. A close relationship between plant roots, rhizodeposits and nanoplastics behaviour was shown. Reinforcement of the cell wall in roots was evidenced using Fourier transform infrared spectroscopy (FTIR) and synchrotron-computed microtomography (µCT). Synchrotron-computed nanotomography (nanoCT) evidenced the presence of globular structures but they could not be identified as nanoplastics since they were observed both in the control and treated roots. By utilizing the inorganic tracer in the doped-nanoplastics, this study paves the road for elucidating interactions in more complex systems by using an integrative approach combining classical phytotoxicity markers with advanced nanometrology techniques.

Nitric oxide-releasing nanomaterials: from basic research to potential biotechnological applications in agriculture

Nitric oxide (NO) is a multifunctional gaseous signal that modulates the growth, development and stress tolerance of higher plants. NO donors have been used to boost plant endogenous NO levels and to activate NO-related responses, but this strategy is often hindered by the relative instability of donors. Alternatively, nanoscience offers a new, promising way to enhance NO delivery to plants, as NO-releasing nanomaterials (e.g. S-nitrosothiol-containing chitosan nanoparticles) have many beneficial physicochemical and biochemical properties compared to non-encapsulated NO donors. Nano NO donors are effective in increasing tissue NO levels and enhancing NO effects both in animal and human systems. The authors believe, and would like to emphasize, that new trends and technologies are essential for advancing plant NO research and nanotechnology may represent a breakthrough in traditional agriculture and environmental science. Herein, we aim to draw the attention of the scientific community to the potential of NO-releasing nanomaterials in both basic and applied plant research as alternatives to conventional NO donors, providing a brief overview of the current knowledge and identifying future research directions. We also express our opinion about the challenges for the application of nano NO donors, such as the environmental footprint and stakeholder's acceptance of these materials.

Nanofertilizers for agricultural and environmental sustainability

Indiscriminate use of chemical fertilizers in the agricultural production systems to keep pace with the food and nutritional demand of the galloping population had an adverse impact on ecosystem services and environmental quality. Hence, an alternative mechanism is to be developed to enhance farm production and environmental sustainability. A nanohybrid construct like nanofertilizers (NFs) is an excellent alternative to overcome the negative impact of traditional chemical fertilizers. The NFs provide smart nutrient delivery to the plants and proves their efficacy in terms of crop productivity and environmental sustainability over bulky chemical fertilizers. Plants can absorb NFs by foliage or roots depending upon the application methods and properties of the particles. NFs enhance the biotic and abiotic stresses tolerance in plants. It reduces the production cost and mitigates the environmental footprint. Multitude benefits of the NFs open new vistas towards sustainable agriculture and climate change mitigation. Although supra-optimal doses of NFs have a detrimental effect on crop growth, soil health, and environmental outcomes. The extensive release of NFs into the environment and food chain may pose a risk to human health, hence, need careful assessment. Thus, a thorough review on the role of different NFs and their impact on crop growth, productivity, soil, and environmental quality is required, which would be helpful for the research of sustainable agriculture.

Surface-enhanced Raman scattering labeled nanoplastic models for reliable bio-nano interaction investigations

Nanoplastics (NPs) have attracted great attention as an emerging pollution. To date, their interaction with biological systems has been studied mostly by using fluorescent-labeled NPs, which suffered from serious drawbacks such as biological autofluorescence interference and false-positive results. Reliable optically labeled NP models are eagerly desired until now. Herein, a novel near-infrared (NIR) surface-enhanced Raman scattering (SERS) labeled NP model was proposed, which gained single-particle ultra-sensitivity, deep tissue detection, multiplex labeling ability, and anti-interference property. More importantly, the NP demonstrated satisfactory in vivo signal stability which completely prevented the positive-false problems. The advantages of the NPs enabled direct, dynamic in vivo behavior imaging study in living zebrafish embryo, adult zebrafish and green vegetable Brassica rapa. It was found for the first time that NPs entered blood circulation system of zebrafish larva via dermal uptake route, which only occurred in a short 48 h-window post-hatch. NPs widely distributed in roots, shoots and leaves of Brassica rapa seedlings germinating and growing in the NP-containing hydroponic culture. Different depths of one root showed varied adsorption capabilities towards NPs with fulvic acid, lipid and sodium dodecyl sulfate eco-coronas. This work provided an ideal tool for reliable bio-NP interaction study for a variety of organisms, which could promote the research of NPs.

Cross-examination of engineered nanomaterials in crop production: Application and related implications

The review presents the current knowledge on the development and implementation of nanotechnology in crop production, giving particular attention to potential opportunities and challenges of the use of nano-sensors, nano-pesticides, and nano-fertilizers. Due to the size-dependent properties, e.g. high reactivity, targeted and controlled delivery of active ingredients, engineered nanomaterials (ENMs) are expected to be more efficient agrochemicals than conventional agents. Growing production and usage of ENMs result in the spread of ENMs in the environment. Because plants constitute an important component of the agri-ecosystem, they are subjected to the ENMs activity. A number of studies have confirmed the uptake and translocation of ENMs by plants as well as their positive/negative effects on plants. Here, these endpoints are briefly summarized to show the diversity of plant responses to ENMs. The review includes a detailed molecular analysis of ENMs-plant interactions. The transcriptomics, proteomics and metabolomics tools have been very recently employed to explore ENMs-induced effects in planta. The omics approach allows a comprehensive understanding of the specific machinery of ENMs occurring at the molecular level. The summary of data will be valuable in defining future studies on the ENMs-plant system, which is crucial for developing a suitable strategy for the ENMs usage.

The dichotomy of nanotechnology as the cutting edge of agriculture: Nano-farming as an asset versus nanotoxicity

The unprecedented setbacks and environmental complications, faced by global agro-farming industry, have led to the advent of nanotechnology in agriculture, which has been recognized as a novel and innovative approach in development of sustainable farming practices. The agricultural regimen is the "head honcho" of the world, however presently certain approaches have been imposing grave danger to the environment and human civilization. The nano-farming paradigm has successfully elevated the growth and development of plants, parallel to the production, quality, germination/transpiration index, photosynthetic machinery, genetic progression, and so on. This has optimized the traditional farming into precision farming, utilising nano-based sensors and nanobionics, smart delivery tools, nanotech facets in plant disease management, nanofertilizers, enhancement of plant adaptive potential to external stress, role in bioenergy conservation and so on. These applications portray nanorevolution as "the big cheese" of global agriculture, mitigating the bottlenecks of conventional practices. Besides the applications of nanotechnology, the review identifies the limitations, like possible harmful impact on environment, mankind and plants, as the "Achilles heel" in agro-industry, aiming to establish its defined role in agriculture, while simultaneously considering the risks, in order to resolve them, thus abiding by "technology-yes, but safety-must". The authors aim to provide a significant opportunity to the nanotech researchers, Botanists and environmentalists, to promote judicial use of nanoparticles and establish a secure and safe environment.

Uptake, translocation, and transformation of silver nanoparticles in plants

This article reviews the plant uptake of silver nanoparticles (AgNPs) that occurred in soil systems and the in planta fate of Ag.

Recent advances in responses of arbuscular mycorrhizal fungi - Plant symbiosis to engineered nanoparticles

The application of engineered nanomaterials (ENMs) is increasing in all walks of life, inevitably resulting in a high risk of ENMs entering the natural environment. Recent studies have demonstrated that phytoaccumulation of ENMs in the environment may be detrimental to plants to varying degrees. However, plants primarily assimilate ENMs through the roots, which are inevitably affected by rhizomicroorganisms. In this review, we focus on a group of common rhizomicroorganisms-arbuscular mycorrhizal fungi (AMF). These fungi contribute to ENMs immobilization and inhibition of phytoaccumulation, improvement of host plant growth and activation of systematic protection in response to excess ENMs stress. In present review, we summarize the biological responses of plants to ENMs and the modulatory mechanisms of AMF on the immobilization of ENMs in substrate-plant interfaces, and indirectly regulatory mechanisms of AMF on the deleterious effects of ENMs on host plants. In addition, the information of feedback of ENMs on mycorrhizal symbiosis and the prospects of future research on the fate and mechanism of phyto-toxicity of ENMs mediated by AMF in the environment are also addressed. In view of above, synergistic reaction of plants and AMF may prove to be a cost-effective and eco-friendly technology to bio-control potential ENMs contamination on a sustainable basis.

Selectively Tracking Nanoparticles in Aquatic Plant Using Core-Shell Nanoparticle-Enhanced Raman Spectroscopy Imaging

Nanoparticles contribute to enormous environmental processes, but, due to analytical challenges, the understanding of nanoparticle fate remains elusive in complex environmental matrices. To address the challenge, a core-shell nanoparticle-enhanced Raman spectroscopy (CSNERS) imaging method was developed to selectively track prevalent SiO₂ nanoparticles in an aquatic plant, Lemna minor. By encapsulating gold nanoparticles and Raman reporters inside, the resonance Raman signature was enhanced, thus enabling the sensitive and selective detection of SiO₂ nanoparticles at an environmentally relevant concentration. The panoramic visualization of the translocation pathway of nanoparticles shows an unexpected, fast (in hours) and a preferential accumulation of nanoparticles on the node, leaf edge, root cap, etc., implying the ability of CSNERS to spectroscopically determine nanotoxicity. The core-shell design in CSNERS was capable of multiplex labeling two differently charged nanoparticles and distinguishing their biobehavior simultaneously. Meanwhile, the CSNERS method can be further applied for a variety of nanoparticles, implying its promising applications for nanotoxicity research and biogeochemical study.

Growth-Promoting Gold Nanoparticles Decrease Stress Responses in Arabidopsis Seedlings

The global economic success of man-made nanoscale materials has led to a higher production rate and diversification of emission sources in the environment. For these reasons, novel nanosafety approaches to assess the environmental impact of engineered nanomaterials are required. While studying the potential toxicity of metal nanoparticles (NPs), we realized that gold nanoparticles (AuNPs) have a growth-promoting rather than a stress-inducing effect. In this study we established stable short- and long-term exposition systems for testing plant responses to NPs. Exposure of plants to moderate concentrations of AuNPs resulted in enhanced growth of the plants with longer primary roots, more and longer lateral roots and increased rosette diameter, and reduced oxidative stress responses elicited by the immune-stimulatory PAMP flg22. Our data did not reveal any detrimental effects of AuNPs on plants but clearly showed positive effects on growth, presumably by their protective influence on oxidative stress responses. Differential transcriptomics and proteomics analyses revealed that oxidative stress responses are downregulated whereas growth-promoting genes/proteins are upregulated. These omics datasets after AuNP exposure can now be exploited to study the underlying molecular mechanisms of AuNP-induced growth-promotion.

Uptake and Accumulation of Nano/Microplastics in Plants: A Critical Review

The ubiquitous presence of microplastics (MPs) and nanoplastics (NPs) in the environment is an undeniable and serious concern due to their higher persistence and extensive use in agricultural production. This review highlights the sources and fate of MPs and NPs in soil and their uptake, translocation, and physiological effects in the plant system. We provide the current snapshot of the latest reported studies with the majority of literature spanning the last five years. We draw attention to the potential risk of MPs and NPs in modern agriculture and their effects on plant growth and development. We also highlight their uptake and transport pathways in roots and leaves via different exposure methods in plants. Conclusively, agricultural practices, climate changes (wet weather and heavy rainfall), and soil organisms play a major role in transporting MPs and NPs in soil. NPs are more prone to enter plant cell walls as compared to MPs. Furthermore, transpiration pull is the dominant factor in the plant uptake and translocation of plastic particles. MPs have negligible negative effects on plant physiological and biochemical indicators. Overall, there is a dire need to establish long-term studies for a better understanding of their fate and associated risks mechanisms in realistic environment scenarios for safe agricultural functions.

X-ray computed tomography for 3D plant imaging

X-ray computed tomography (CT) is a valuable tool for 3D imaging of plant tissues and organs. Applications include the study of plant development and organ morphogenesis, as well as modeling of transport processes in plants. Some challenges remain, however, including attaining higher contrast for easier quantification, increasing the resolution for imaging subcellular features, and decreasing image acquisition and processing time for high-throughput phenotyping. In addition, phase contrast, multispectral, dark-field, soft X-ray, and time-resolved imaging are emerging. At the same time, a large amount of 3D image data are becoming available, posing challenges for data management. We review recent advances in the area of X-ray CT for plant imaging, and describe opportunities for using such images for studying transport processes in plants.

Engineering of 177Lu-labeled gold encapsulated into dendrimeric nanomaterials for the treatment of lung cancer

As a novel type of theranostic radioactive agents, ¹⁷⁷Lu-labeled nanomaterials conjugated to macromolecules have been described. The study aimed to fabricate PAMAM-G4-(¹⁷⁷Lu-dendrimer)-bombesin-folate in the dendrimeric cavity, assess the radiopharmaceutical ability for specifically targeted radiotherapy and simultaneously detects gastrin-releasing peptide receptors (GRPR) and folate receptors (FRs) overexpressed in lung carcinoma cells, respectively. In an aqueous-basic media, p-SCN-benzyl-DOTA was conjugated to the dendrimer. This dendrimer was formed by activating the carboxylic acid groups of DOTA-folic acid and bombesin with HATU and conjugating them to develop the dendrimer. As part of this process, the conjugate was combined with 1% HAuCl₄, added NaBH₄ and filtered by ultrafiltration. Infrared, UV-Vis, TEM analysis, dynamic light scattering (DLS), and fluorescence spectroscopy were employed to observe the composition of the fabricated sample. Radio-labeled ¹⁷⁷LuCl₃ was used to label the conjugate, which was then evaluated using the radio-HPLC method. Findings demonstrated dendrimeric functionalization with remarkable radiochemical composition purity up to >96%. Because of fluorescence studies, it was determined that the occurrence of AuNMs in the dendrimeric cavities gives beneficial photo-physical characteristics to the radiopharmaceutical for bio-imaging. HEL-299 lung cancer cells exhibited a selective absorption of the drug (%). It might be helpful as nuclear and optical imaging agents for lung cancers that overexpress FRs and GRPR and as a specific target for radiation therapy if combined with folate-bombesin.

In Planta Nanosensors: Understanding Biocorona Formation for Functional Design

Climate change and population growth are straining agricultural output. To counter these changes and meet the growing demand for food and energy, the monitoring and engineering of crops are becoming increasingly necessary. Nanoparticle-based sensors have emerged in recent years as new tools to advance agricultural practices. As these nanoparticle-based sensors enter and travel through the complex biofluids within plants, biomolecules including proteins, metabolites, lipids, and carbohydrates adsorb onto the nanoparticle surfaces, forming a coating known as the "bio-corona". Understanding these nanoparticle-biomolecule interactions that govern nanosensor function in plants will be essential to successfully develop and translate nanoparticle-based sensors into broader agricultural practice.

Cross-Species Comparisons of Nanoparticle Interactions with Innate Immune Systems: A Methodological Review

Many components of the innate immune system are evolutionarily conserved and shared across many living organisms, from plants and invertebrates to humans. Therefore, these shared features can allow the comparative study of potentially dangerous substances, such as engineered nanoparticles (NPs). However, differences of methodology and procedure between diverse species and models make comparison of innate immune responses to NPs between organisms difficult in many cases. To this aim, this review provides an overview of suitable methods and assays that can be used to measure NP immune interactions across species in a multidisciplinary approach. The first part of this review describes the main innate immune defense characteristics of the selected models that can be associated to NPs exposure. In the second part, the different modes of exposure to NPs across models (considering isolated cells or whole organisms) and the main endpoints measured are discussed. In this synergistic perspective, we provide an overview of the current state of important cross-disciplinary immunological models to study NP-immune interactions and identify future research needs. As such, this paper could be used as a methodological reference point for future nano-immunosafety studies.

Advantage of Nanotechnology-Based Genome Editing System and Its Application in Crop Improvement

Agriculture is an important source of human food. However, current agricultural practices need modernizing and strengthening to fulfill the increasing food requirements of the growing worldwide population. Genome editing (GE) technology has been used to produce plants with improved yields and nutritional value as well as with higher resilience to herbicides, insects, and diseases. Several GE tools have been developed recently, including clustered regularly interspaced short palindromic repeats (CRISPR) with nucleases, a customizable and successful method. The main steps of the GE process involve introducing transgenes or CRISPR into plants via specific gene delivery systems. However, GE tools have certain limitations, including time-consuming and complicated protocols, potential tissue damage, DNA incorporation in the host genome, and low transformation efficiency. To overcome these issues, nanotechnology has emerged as a groundbreaking and modern technique. Nanoparticle-mediated gene delivery is superior to conventional biomolecular approaches because it enhances the transformation efficiency for both temporal (transient) and permanent (stable) genetic modifications in various plant species. However, with the discoveries of various advanced technologies, certain challenges in developing a short-term breeding strategy in plants remain. Thus, in this review, nanobased delivery systems and plant genetic engineering challenges are discussed in detail. Moreover, we have suggested an effective method to hasten crop improvement programs by combining current technologies, such as speed breeding and CRISPR/Cas, with nanotechnology. The overall aim of this review is to provide a detailed overview of nanotechnology-based CRISPR techniques for plant transformation and suggest applications for possible crop enhancement.