Recent Advances and Perspectives of Nanomaterials in Agricultural Management and Associated Environmental Risk: A Review

Evaluation of the altered enzymatic and pollen activity in sunflower on application of nanoparticles

Nanoparticles play a significant role in enhancing crop yield and reducing nutrient loss through precise nutrient delivery mechanisms. However, it is imperative to ascertain the specific plant physiology altered by these nanoparticles. This study investigates the effects of green-synthesized nanoparticles, specifically boron nitride and sulphur, on sunflower yield, seed quality, and physiological activities. Conducted over two field experiments in 2019 and 2020, the research assesses the efficacy of these nanoparticles compared to traditional fertilizers. The first experiment revealed that a foliar application of green-synthesized nano boron nitride at 1500 ppm significantly enhanced seed yield (65.45 g in 2019 and 63.27 g in 2020), increased filled seed count, and reduced chaffiness. Additionally, this treatment improved pollen fertility, germination rates, and pollen tube growth compared to higher concentrations and borax treatments. These findings indicate that nano boron nitride enhances esterase activity, contributing to improved reproductive performance in sunflower. The second experiment focused on green-synthesized nano sulphur, comparing foliar application and seed treatment. Results showed that a foliar application at 600 ppm led to increased head diameter, head weight, and 100-seed weight outperforming both seed treatment and chemically synthesized alternatives. Overall, this research demonstrates the potential of green-synthesized nanoparticles to enhance sunflower crop characteristics and oil production, offering valuable insights for sustainable agricultural practices.

Biogenic nanoparticles and its application in crop protection against abiotic stress: A new dimension in agri-nanotechnology

The food demand to support the growing population worldwide is expected to increase up to 60 % by 2050. But, various abiotic stress including heat, drought, salinity, and heavy metal stress are becoming more prevalent due to global warming and seriously affecting the crop productivity. Nanotechnology has a great potential to solve this issue, as various nanoparticles (NPs) with their unique physical and chemical characteristics, have shown promising ability to enhance the stress tolerance and subsequently, improving the plant growth and development. Although NPs can be synthesized either via physically or chemically or biologically, application of biogenic NPs in agriculture are gaining strong attention due to their economic, environmental friendly, and sustainable benefits. The implementations of biogenic NPs have been reported to be enhancing both the quantitative and qualitative properties of crop production significantly by mitigating abiotic stress. Hence, this review paper critically discussed the application of biogenic NPs, synthesized using various biological methods i.e. bacteria, fungi, algae, and plant-based, in enhancing the abiotic stress resilience and crop production. Adverse effects of the major abiotic stresses on crops have also been highlighted in the paper. The paper also focused on the mechanistic insights of plant-NPs interactions, uptake, translocation and NPs-induced biochemical and molecular changes in plants to help mitigating the abiotic stress. The potential challenges and environmental implications of extensive use of biogenic NPs in agriculture compared to the chemogenic NPs has also been critically assessed. Future research direction is provided to delve into the potential of biogenic NPs as promising tools for mitigating abiotic stress, and improving plant growth and development for a sustainable agriculture via nanotechnology.

Rhamnolipid Modified Silica Nanoparticles Control Rice Blast Disease by Enhancing Antifungal Activity In Vivo and Antioxidant Defense System of Rice (Oryza sativa L.)

Blast disease caused by Magnaporthe oryzae is a devastating disease that limits rice grain production. Here, we synthesized rhamnolipid (RL) modified silica nanoparticles (SiO2NPs) based on the excellent antimicrobial activity of RL against various phytopathogens and the role of SiO2NPs in alleviating plant diseases and investigated the roles and mechanisms of RL@SiO2NPs application in controlling rice blast disease. Two-week-old rice seedlings were sprayed with 100 mL/L of different materials before pathogen inoculation, and blast incidence was investigated 5 days after inoculation. The results showed that RL0.1@SiO2NPs were the most suitable mixture ratio in suppressing blast and enhanced plant resistance. Compared with the control, application of RL0.1@SiO2NPs significantly reduced rice blast disease incidence by 10.80% and the relative growth of fungus by 97.05% and increased the shoot dry biomass by 13.33%, which alleviated the infection pressure of rice blast fungus. Additionally, after RL0.1@SiO2NPs treatment, peroxidase, ascorbate peroxidase, and polyphenol oxidase activities in rice leaves were significantly increased by 47.02%, 34.26%, and 44.36%, respectively, the total phenolics content was significantly increased by 24.14%, and the malondialdehyde and hydrogen peroxide content was decreased by 5.28% and 14.58%, respectively. RL0.1@SiO2NPs also improved plant nutrient status and enhanced disease resistance of infected plants by restoring nutrient balance or ion homeostasis, including increased potassium concentration (23.84%) in leaves and Si concentration (60.34%) in roots and decreased magnesium (11.89%) and iron concentrations (30.55%) in rice leaves. In summary, our results suggest that RL0.1@SiO2NPs enhance rice plant resistance against blast by enhancing the antifungal activity in vivo, activating the antioxidant defense system, and affecting nutrient acquisition in rice seedlings. RL@SiO2NPs have shown potential application as green and efficient agricultural chemical substitutes in plant disease management.

Plant nutrition challenges for a sustainable agriculture of the future

This article offers a comprehensive review of sustainable plant nutrition concepts, examining a multitude of cutting-edge techniques that are revolutionizing the modern area. The review copes with the crucial role of biostimulants as products that stimulate plant nutrition processes, including their potential for biofertilization, followed by an exploration of the significance of micronutrients in plant health and growth. We then delve into strategies for enhancing plants' tolerance to mineral nutrient contaminants and the promising realm of biofortification to increase the essential nutrients necessary for human health. Furthermore, this work also provides a concise overview of the burgeoning field of nanotechnologies in fertilization, while the integration of circular economy principles underscores the importance of sustainable resource management. Then, with examined the interrelation between micronutrients. We conclude with the future challenges and opportunities that lie ahead in the pursuit of more sustainable and resilient plant systems.

Nanotechnology in sustainable agriculture: A double-edged sword

Nanotechnology is a rapidly developing discipline that has the potential to transform the way we approach problems in a variety of fields, including agriculture. The use of nanotechnology in sustainable agriculture has gained popularity in recent years. It has various applications in agriculture, such as the development of nanoscale materials and devices to boost agricultural productivity, enhance food quality and safety, improve the efficiency of water and nutrient usage, and reduce environmental pollution. Nanotechnology has proven to be very beneficial in this field, particularly in the development of nanoscale delivery systems for agrochemicals such as pesticides, fertilizers, and growth regulators. These nanoscale delivery technologies offer various benefits over conventional delivery systems, including better penetration and distribution, enhanced efficacy, and lower environmental impact. Encapsulating agrochemicals in nanoscale particles enables direct delivery to the targeted site in the plant, thereby reducing waste and minimizing off-target effects. Plants are fundamental building blocks of all ecosystems and evaluating the interaction between nanoparticles (NPs) and plants is a crucial aspect of risk assessment. This critical review therefore aims to provide an overview of the latest advances regarding the positive and negative effects of nanotechnology in agriculture. It also explores potential future research directions focused on ensuring the safe utilization of NPs in this field, which could lead to sustainable development. © 2024 Society of Chemical Industry.

Redox Regulation by Priming Agents Toward a Sustainable Agriculture

Plants are sessile organisms that are often subjected to a multitude of environmental stresses, with the occurrence of these events being further intensified by global climate change. Crop species therefore require specific adaptations to tolerate climatic variability for sustainable food production. Plant stress results in excess accumulation of reactive oxygen species leading to oxidative stress and loss of cellular redox balance in the plant cells. Moreover, enhancement of cellular oxidation as well as oxidative signals has been recently recognized as crucial players in plant growth regulation under stress conditions. Multiple roles of redox regulation in crop production have been well documented, and major emphasis has focused on key redox-regulated proteins and non-protein molecules, such as NAD(P)H, glutathione, peroxiredoxins, glutaredoxins, ascorbate, thioredoxins and reduced ferredoxin. These have been widely implicated in the regulation of (epi)genetic factors modulating growth and health of crop plants, with an agricultural context. In this regard, priming with the employment of chemical and biological agents has emerged as a fascinating approach to improve plant tolerance against various abiotic and biotic stressors. Priming in plants is a physiological process, where prior exposure to specific stressors induces a state of heightened alertness, enabling a more rapid and effective defense response upon subsequent encounters with similar challenges. Priming is reported to play a crucial role in the modulation of cellular redox homeostasis, maximizing crop productivity under stress conditions and thus achieving yield security. By taking this into consideration, the present review is an up-to-date critical evaluation of promising plant priming technologies and their role in the regulation of redox components toward enhanced plant adaptations to extreme unfavorable environmental conditions. The challenges and opportunities of plant priming are discussed, with an aim of encouraging future research in this field toward effective application of priming in stress management in crops including horticultural species.

Biofortification of crops with nutrients by the application of nanofertilizers for effective agriculture

The agricultural industry is rapidly accepting daily changes and updates, and expanding to meet the basic demands of humanity. The main objective of modern agricultural practices is high profits with minimal investment, without upsetting any other form of life or abiotic factors. According to this principle, nanofertilizers are recommended for use in agriculture and are classified in different ways based on their nutritive value, functional role in the environment, chemical composition, and form of application to ensure their persistent availability in the required quantities. These nanofertilizers meet the global crop nutrient requirement of 191.8 million metric tons along with multitudes of added value, and which are highly endorsed in the agricultural field compared to other chemical fertilizers, or their usage can be reduced to less than 50% by the use of nanofertilizers. In this review, we discuss different types of nanofertilizers, their effects on crop yield, stress tolerance, and their impact on the environment. Furthermore, the different types of nanofertilizer delivery, modes of action, and toxic impacts of nanofertilizers have been discussed. Although a large number of commercially successful effects of nanofertilizers have been demonstrated, the effects of biomagnification and cellular transformation are still disputed. The effect of the biomagnification of nanofertilizers remains unclear. A suitable strategy must be developed to easily recycle nanofertilizers. It is the need of the hour to accept the use of nanofertilizers in parallel to addressing this issue.

Nanoparticles and root traits: mineral nutrition, stress tolerance and interaction with rhizosphere microbiota

MAIN CONCLUSION

This review article highlights a broader perspective of NPs and plant-root interaction by focusing on their beneficial and deleterious impacts on root system architecture (RSA). The root performs a vital function by securing itself in the soil, absorbing and transporting water and nutrients to facilitate plant growth and productivity. In dicots, the architecture of the root system (RSA) is markedly shaped by the development of the primary root and its branches, showcasing considerable adaptability in response to changes in the environment. For promoting agriculture and combating global food hunger, the use of nanoparticles (NPs) may be an exciting option, for which it is essential to understand the behaviour of plants under NPs exposure. The nature of NPs and their physicochemical characteristics play a significant role in the positive/negative response of roots and shoots. Root morphological features, such as root length, root mass and root development features, may regulated positively/negatively by different types of NPs. In addition, application of NPs may also enhance nutrient transport and soil fertility by the promotion of soil microorganisms including plant growth-promoting rhizobacteria (PGPRs) and also soil enzymes. Interestingly the interaction of nanomaterials (NMs) with rhizospheric bacteria can enhance plant development and soil health. However, some studies also suggested that the increased use of several types of engineered nanoparticles (ENPs) may disrupt the equilibrium of the soil-root interface and unsafe morphogenesis by causing the browning of roots and suppressing the growth of root and soil microbes. Thus, this review article has sought to compile a broader perspective of NPs and plant-root interaction by focusing on their beneficial or deleterious impacts on RSA.

Role of particle size-dependent copper bioaccumulation-mediated oxidative stress on Glycine max (L.) yield parameters with soil-applied copper oxide nanoparticles

Increased impetus on the application of nano-fertilizers to improve sustainable food production warrants understanding of nanophytotoxicity and its underlying mechanisms before its application could be fully realized. In this study, we evaluated the potential particle size-dependent effects of soil-applied copper oxide nanoparticles (nCuO) on crop yield and quality attributes (photosynthetic pigments, seed yield and nutrient quality, seed protein, and seed oil), including root and seed Cu bioaccumulation and a suite of oxidative stress biomarkers, in soybean (Glycine max L.) grown in field environment. We synthesized three distinct sized (25 nm = S [small], 50 nm = M [medium], and 250 nm = L [large]) nCuO with same surface charge and compared with soluble Cu2+ ions (CuCl2) and water-only controls. Results showed particle size-dependent effects of nCuO on the photosynthetic pigments (Chla and Chlb), seed yield, potassium and phosphorus accumulation in seed, and protein and oil yields, with nCuO-S showing higher inhibitory effects. Further, increased root and seed Cu bioaccumulation led to concomitant increase in oxidative stress (H2O2, MDA), and as a response, several antioxidants (SOD, CAT, POX, and APX) increased proportionally, with nCuO treatments including Cu2+ ion treatment. These results are corroborated with TEM ultrastructure analysis showing altered seed oil bodies and protein storage vacuoles with nCuO-S treatment compared to control. Taken together, we propose particle size-dependent Cu bioaccumulation-mediated oxidative stress as a mechanism of nCuO toxicity. Future research investigating the potential fate of varied size nCuO, with a focus on speciation at the soil-root interface, within the root, and edible parts such as seed, will guide health risk assessment of nCuO.

Bioinspired silver nanoparticle-based nanocomposites for effective control of plant pathogens: A review

Plant pathogens, including bacteria, fungi, and viruses, pose significant challenges to the farming community due to their extensive diversity, the rapidly evolving phenomenon of multi-drug resistance (MDR), and the limited availability of effective control measures. Amid mounting global pressure, particularly from the World Health Organization, to limit the use of antibiotics in agriculture and livestock management, there is increasing consideration of engineered nanomaterials (ENMs) as promising alternatives for antimicrobial applications. Studies focusing on the application of ENMs in the fight against MDR pathogens are receiving increasing attention, driven by significant losses in agriculture and critical knowledge gaps in this crucial field. In this review, we explore the potential contributions of silver nanoparticles (AgNPs) and their nanocomposites in combating plant diseases, within the emerging interdisciplinary arena of nano-phytopathology. AgNPs and their nanocomposites are increasingly acknowledged as promising countermeasures against plant pathogens, owing to their unique physicochemical characteristics and inherent antimicrobial properties. This review explores recent advancements in engineered nanocomposites, highlights their diverse mechanisms for pathogen control, and draws attention to their potential in antibacterial, antifungal, and antiviral applications. In the discussion, we briefly address three crucial dimensions of combating plant pathogens: green synthesis approaches, toxicity-environmental concerns, and factors influencing antimicrobial efficacy. Finally, we outline recent advancements, existing challenges, and prospects in scholarly research to facilitate the integration of nanotechnology across interdisciplinary fields for more effective treatment and prevention of plant diseases.