Nanomaterials are used in practically every aspect of modern life, including agriculture. The aim of this study was to evaluate the effectiveness of iron oxide nanoparticles (Fe₂O₃ NPs) as a fertilizer to replace traditional Fe fertilizers, which have various shortcomings. The effects of the Fe₂O₃ NPs and a chelated-Fe fertilizer (ethylenediaminetetraacetic acid-Fe; EDTA-Fe) fertilizer on the growth and development of peanut (Arachis hypogaea), a crop that is very sensitive to Fe deficiency, were studied in a pot experiment. The results showed that Fe₂O₃ NPs increased root length, plant height, biomass, and SPAD values of peanut plants. The Fe₂O₃ NPs promoted the growth of peanut by regulating phytohormone contents and antioxidant enzyme activity. The Fe contents in peanut plants with Fe₂O₃ NPs and EDTA-Fe treatments were higher than the control group. We used energy dispersive X-ray spectroscopy (EDS) to quantitatively analyze Fe in the soil. Peanut is usually cultivated in sandy soil, which is readily leached of fertilizers. However, the Fe₂O₃ NPs adsorbed onto sandy soil and improved the availability of Fe to the plants. Together, these results show that Fe₂O₃ NPs can replace traditional Fe fertilizers in the cultivation of peanut plants. To the best of our knowledge, this is the first research on the Fe₂O₃ NPs as the iron fertilizer.

Diverse applications of nanoparticles (NPs) have revolutionized various sectors in society. In the recent decade, particularly magnetic nanoparticles (MNPs) have gained enormous interest owing to their applications in specialized areas such as medicine, cancer theranostics, biosensing, catalysis, agriculture, and the environment. Controlled surface engineering for the design of multi-functional MNPs is vital for achieving desired application. The MNPs have demonstrated great efficacy as thermoelectric materials, imaging agents, drug delivery vehicles, and biosensors. In the present review, first we have briefly discussed main synthetic methods of MNPs, followed by their characterizations and composition. Then we have discussed the potential applications of MNPs in different with representative examples. At the end, we gave an overview on the current challenges and future prospects of MNPs. This comprehensive review not only provides the mechanistic insight into the synthesis, functionalization, and application of MNPs but also outlines the limits and potential prospects.

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.

With the rapid development of nanotechnology, the potential releases of nanoparticles (NPs) have drawn considerable attention. Plants are essential fundamental components of all ecosystems, and the interaction between NPs and plants is an indispensable aspect of the risk assessment. Originally, this review focuses on NP phytotoxicity, which is an important precondition to promote the application of nanotechnology and to avoid the potential ecological risks. Both enhancive and inhibitive effects of various NPs on different plants’ growth have been documented. In this paper, the influence factors of nanotoxicity and the mechanisms of these toxic effects are also summarized. Subsequently, the defense mechanisms are presented as well. Eventually, this review puts forward the prospects of research direction of the environmental behavior and the biological toxicity of NPs, hoping to bring new ideas to the further research on NP phytotoxicity. Abbreviations: ¹O₂: singlet oxygen; AA: ascorbate; ABA: abscisic acid; APX: ascorbate peroxidase; B-Ag NPs: biosynthesized silver nanoparticles; Bt: Bacillus thuringiensis; CAT: catalase; CDs: carbon dots; Cu/Zn-SOD: copper/Zinc SOD; DHA: dehydroascorbate; DHAR: dehydroascorbate reductase; GA: gibberellic acid: GA-Ag NPs: coated silver nanoparticles; GPOX: guaiacol peroxidase; GPX: glutathione peroxidase; GR: glutathione reductase; GSH: glutathione; GSSG: oxidized glutathione; GST: glutathione S-transferases; •OH: hydroxyl radical; HA: high amylose; IAA: indole-3-acetic acid; LA: low amylose; MA: medium amylose; MDA: malondialdehyde; MDHAR: monodehydroascorbate reductase; NPs: nanoparticles; ${\text{O}}_2^{\bullet -}$: superoxide radical; POD: promoting peroxidase; ROS: reactive oxygen species; SOD: superoxide dismutase; t-ZR: trans-zeatin-riboside

Heavy metal pollution is not only a hazard to living organisms but also an important worldwide environmental concern. Experiments were performed to investigate the physiological mechanisms of magnetic (Fe₃O₄) nanoparticles (nano-Fe₃O₄) mitigation of the toxicity of heavy metals (Pb, Zn, Cd and Cu) in wheat seedlings. All the Petri dishes with germinating seedlings (1d) were covered, sealed with parafilm, and placed in a dark growth chamber. All parameters (seedling growth inhibition, heavy metal accumulation, enzymatic activities, and reducing effects of nano-Fe₃O₄ on heavy metal toxicity) were analyzed only after five days. The results showed that the tested heavy metals significantly affected the growth of wheat seedling by decreasing root length, shoot length and even death at 10 mM concentration in the case of Cd and Cu. Heavy metals exposure also showed that superoxide dismutase (SOD) and peroxidases (POD) activities decreased significantly when the malondialdehyde (MDA) content was significantly higher in wheat seedlings. Addition of magnetic (Fe₃O₄) nanoparticles (2000 mg/L) in each heavy metal solution (1 mM) significantly decreased the growth inhibition and activated protective mechanisms to reduce oxidative stress induced by heavy metals in the wheat seedlings. The reducing effects of nano-Fe₃O₄ against heavy metals stress could be dependent on the increase in the enzyme activity (SOD and POD). Their protective role was confirmed by the decrease in MDA content. The alleviating effect of nano-Fe₃O₄ is associated with their adsorption capacity of heavy metals.

Nanotechnology is playing a significant role in addressing a vast range of environmental challenges by providing innovative and effective solutions. Heavy metal (HM) contamination has gained considerable attention in recent years due their rapidly increasing concentrations in agricultural soil. Due to their unique physiochemical properties, nanoparticles (NPs) can be effectively applied for stress alleviation. In this review, we explore the current status of the literature regarding nano-enabled agriculture retrieved from the Web of Science databases and published from January 2010 to November 2020, with most of our sources spanning the past five years. We briefly discuss uptake and transport mechanisms, application methods (soil, hydroponic and foliar), exposure concentrations, and their impact on plant growth and development. The current literature contained sufficient information about NPs behavior in plants in the presence of pollutants, highlighting the alleviation mechanism to overcome the HM stress. Furthermore, we present a broad overview of recent advances regarding HM stress and the possible mechanism of interaction between NPs and HM in the agricultural system. Additionally, this review article will be supportive for the understanding of phytoremediation and micro-remediation of contaminated soils and also highlights the future research needs for the combined application of NPs in the soil for sustainable agriculture.