Knowledge domain and emerging trends in nanoparticles and plants interaction research: A scientometric analysis

Effects of particle size on toxicity, bioaccumulation, and translocation of zinc oxide nanoparticles to bok choy (Brassica chinensis L.) in garden soil

The indiscriminate use of zinc oxide nanoparticles (ZnO NPs) in daily life can lead to their release into soil environment. These ZnO NPs can be taken up by crops and translocated to their edible part, potentially causing risks to the ecosystem and human health. In this study, we conducted pot experiments to determine phytotoxicity, bioaccumulation and translocation depending on the size (10 - 30 nm, 80 - 200 nm and 300 nm diameter) and concentration (0, 100, 500 and 1000 mg Zn/kg) of ZnO NPs and Zn ion (Zn2+) in bok choy, a leafy green vegetable crop. After 14 days of exposure, our results showed that large-sized ZnO NPs (i.e., 300 nm) at the highest concentration exhibited greater phytotoxicity, including obstruction of leaf and root weight (42.5 % and 33.8 %, respectively) and reduction of chlorophyll a and b content (50.2 % and 85.2 %, respectively), as well as changes in the activities of oxidative stress responses compared to those of small-sized ZnO NPs, although their translocation ability was relatively lower than that of smaller ones. The translocation factor (TF) values decreased as the size of ZnO NPs increased, with TF values of 0.68 for 10 - 30 nm, 0.55 for 80 - 200 nm, and 0.27 for 300 nm ZnO NPs, all at the highest exposure concentration. Both the results of micro X-ray fluorescence (μ-XRF) spectrometer and bio-transmission electron microscopy (bio-TEM) showed that the Zn elements were mainly localized at the edges of leaves exposed to small-sized ZnO NPs. However, the Zn elements upon exposure to large-sized ZnO NP were primarily observed in the primary veins of leaves in the μ-XRF data, indicating a limitation in their ability to translocate from roots to leaves. This study not only advances our comprehension of the environmental impact of nanotechnology but also holds considerable implications for the future of sustainable agriculture and food safety.

Articles in the field of infertility (2013-2022): a bibliometric analysis

To carry out an in-depth analysis of the scientific research on infertility, we performed the first bibliometric analysis focusing on studies involving global literature on infertility during the period 2013-2022. Analysis of 33239 articles in the field of infertility showed a significant increasing trend in the number of publications over the period 2013-2022, with authors mainly from the USA and China. Shanghai Jiao Tong University published the most articles. This study is the first to analyze the global field of infertility (2013-2022) from multiple indicators by bibliometrics, thus providing new insights into the research hotspots and development trends in the field of infertility.

Toxicity effects of polystyrene nanoplastics and arsenite on Microcystis aeruginosa

Despite the increasing research on the fate of nanoplastics (NPs, <100 nm) in freshwater systems, little is known about the joint toxic effects of metal(loid)s and NPs modified with different functional groups on microalgae. Here, we explored the joint toxic effects of two types of polystyrene NPs [one modified with a sulfonic acid group (PSNPs-SO₃H), and one without this functional group (PSNPs)] and arsenic (As) on the microalgae Microcystis aeruginosa. The results highlighted that PSNPs-SO₃H showed a smaller hydrodynamic diameter and greater potential to adsorb positively charged ions than PSNPs, contributing to the more severe growth inhibition, while both of them produced oxidative stress. Metabolomics further revealed that the fatty acid metabolism of the microalgae was significantly up-regulated under both NPs exposure, while PSNPs-SO₃H down-regulated the tricarboxylic acid cycle (TCA cycle) of the microalgae. As uptake by algae was significantly reduced by 82.58 % and 59.65 % in the presence of 100 mg/L PSNPs and PSNPs-SO₃H, respectively. The independent action model showed that the joint toxicity of both NPs with As was assessed as antagonistic. In addition, PSNPs and PSNPs-SO₃H had dissimilar effects on the composition of the microalgae extracellular polymeric substances (EPS), resulting in different uptake and adsorption of As, thereby affecting the physiology and biochemistry of algae. Overall, our findings propose that the specific properties of NPs should be considered in future environmental risk assessments.

Modulations in protein phosphorylation explain the physiological responses of barley (Hordeum vulgare) to nanoplastics and ZnO nanoparticles

To address the knowledge gap on the effects of the co-existence of nanomaterials on plant growth, barley (Hordeum vulgare L.) plants were irrigated with zinc oxide nanoparticles (0.5 g L^-1), nanoplastics (1 g L^-1), and the combination of these two nanomaterials for 10 days. The co-existence of nanoplastics and ZnO nanoparticles increased H₂O₂ concentration by 12.76% and 38.30%, compared with the ZnO nanoparticles and nanoplastics exposure. The concentration of abscisic acid (ABA) in plants under the co-existence of nanoplastics and ZnO nanoparticles was 29.53% and 10.42% higher than that in ZnO nanoparticles treated plants and nanoplastics treated plants. The global analysis of phosphoproteomics identified 132 phosphorylated proteins and 173 phosphorylation sites in barley leaves exposed to the nanomaterial combination, which were related to photosynthesis, carbon fixation, nitrogen metabolism, and arginine and proline metabolisms. Further physiological analysis indicated that the combination of ZnO nanoparticles and nanoplastics caused larger damage to the systems of antioxidant and carbohydrate metabolisms as exemplified by decreased activities of apoplastic peroxidases (25.10%-48.60%), glutathione reductase (91.07%-94.94%), and sucrose synthase (53.59%-61.19%) in roots and increased cell wall invertase activity (12.97%-17.61%) in leaves, compared with the single nanomaterial treatments. These results indicate that the modulations in protein phosphorylation were closely related to the physiological responses to nanomaterial exposure, suggesting that the co-existence of nanomaterials may lead to greater impacts than single ones.

Metabolomics as a Tool to Understand Nano-Plant Interactions: The Case Study of Metal-Based Nanoparticles

Metabolomics is a powerful tool in diverse research areas, enabling an understanding of the response of organisms, such as plants, to external factors, their resistance and tolerance mechanisms against stressors, the biochemical changes and signals during plant development, and the role of specialized metabolites. Despite its advantages, metabolomics is still underused in areas such as nano-plant interactions. Nanoparticles (NPs) are all around us and have a great potential to improve and revolutionize the agri-food sector and modernize agriculture. They can drive precision and sustainability in agriculture as they can act as fertilizers, improve plant performance, protect or defend, mitigate environmental stresses, and/or remediate soil contaminants. Given their high applicability, an in-depth understanding of NPs' impact on plants and their mechanistic action is crucial. Being aware that, in nano-plant interaction work, metabolomics is much less addressed than physiology, and that it is lacking a comprehensive review focusing on metabolomics, this review gathers the information available concerning the metabolomic tools used in studies focused on NP-plant interactions, highlighting the impact of metal-based NPs on plant metabolome, metabolite reconfiguration, and the reprogramming of metabolic pathways.

Engineered Zn-based nano-pesticides as an opportunity for treatment of phytopathogens in agriculture

People's desire for food has never slowed, despite the deterioration of the global agricultural environment and the threat to food security. People rely on agrochemicals to ensure normal crop growth and to relieve the existing demand pressure. Phytopathogens have acquired resistance to traditional pesticides as a result of pesticdes' abuse. Compared with traditional formulations, nano-pesticides have superior antimicrobial performance and are environmentally friendly. Zn-based nanoparticles (NPs) have shown their potential as strong antipathogen activity. However, their full potential has not been demonstrated yet. Here, we analyzed the prerequisites for the use of Zn-based NPs as nano-pesticides in agriculture including both intrinsic properties of the materials and environmental conditions. We also summarized the mechanisms of Zn-based NPs against phytopathogens including direct and indirect strategies to alleviate plant disease stress. Finally, the current challenges and future directions are highlighted to advance our understanding of this field and guide future studies.

Phytotoxicity of polystyrene, polyethylene and polypropylene microplastics on tomato (Lycopersicon esculentum L.)

Despite the fact that microplastic pollution in terrestrial ecosystems has received increasing attention, there are few studies on the potential effects of different microplastics on terrestrial plants. In this study, the toxicity of polystyrene (PS), polyethylene (PE) and polypropylene (PP) microplastics with different concentrations (0, 10, 100, 500 and 1000 mg/L) to tomato (Lycopersicon esculentum L.) were studied by a hydroponic experiment. The results showed that the three microplastics had inhibitory effects on seed germination when the concentration was less than or equal to 500 mg/L, and the inhibition rate ranged from 10.1% to 23.6%. Interestingly, the inhibition effect was alleviated under 1000 mg/L microplastic treatment. Generally, PE was more toxic to seedling growth than PS and PP. Additionally, it was confirmed that microplastics could cause oxidative stress in plants, and PP was relatively less toxic to antioxidant enzymes than PS and PE. These results can provide a theoretical basis and data support for further investigation on the toxicity of microplastics to tomatoes, and contribute to understanding the type specificity of microplastics' toxic effects on plants.

Cooling the City? A Scientometric Study on Urban Green and Blue Infrastructure and Climate Change-Induced Public Health Effects

Climate change causes global effects on multiple levels. The anthropogenic input of greenhouse gases increases the atmospheric mean temperature. It furthermore leads to a higher probability of extreme weather events (e.g., heat waves, floods) and thus strongly impacts the habitats of humans, animals, and plants. Against this background, research and innovation activities are increasingly focusing on potential health-related aspects and feasible adaptation and mitigation strategies. Progressing urbanization and demographic change paired with the climate change-induced heat island effect exposes humans living in urban habitats to increasing health risks. By employing scientometric methods, this scoping study provides a systematic bird’s eye view on the epistemic landscapes of climate change, its health-related effects, and possible technological and nature-based interventions and strategies in order to make urban areas climate proof. Based on a literature corpus consisting of 2614 research articles collected in SCOPUS, we applied network-based analysis and visualization techniques to map the different scientific communities, discourses and their interrelations. From a public health perspective, the results demonstrate the range of either direct or indirect health effects of climate change. Furthermore, the results indicate that a public health-related scientific discourse is converging with an urban planning and building science driven discourse oriented towards urban blue and green infrastructure. We conclude that this development might mirror the socio-political demand to tackle emerging climate change-induced challenges by transgressing disciplinary boundaries.

Phytotoxic effect of sub-3-nm crystalline ceria nanoparticles on the hydroponic growth of Daikon radish microgreens

Cerium oxide nanoparticles (ceria NPs) have been widely used in many industrial applications. They have been proposed as a potential remedy for reducing oxidative stress in biological systems. General concerns over the toxicity of engineered ceria NPs have led to studies of their phytotoxicity in plants. Most of these plant growth studies were conducted in soil using grain crops and commercial ceria NPs of sizes from 6 nm to 100's nm. In this paper, we report our evaluation of the phytotoxicity and uptake of sub-3-nm crystalline ceria NPs by exposing Daikon radish (Raphanus sativus var. longipinnatus) microgreens to these NPs with environmentally relevant concentrations under hydroponic growth conditions. Aqueous suspensions of different concentrations of these ceria NPs (0.1 ppm, 1 ppm, and 10 ppm) were applied to these microgreens for the last 7 days of the 12-day growth period. Our results revealed the uptake of cerium by plant roots and the translocation of cerium to the stems and the cotyledons (seed leaves). The accumulation of cerium was found to be maximum at the roots, followed by the cotyledons and the stems of the plants. Even at the lowest concentration (0.1 ppm) of the sub-3-nm ceria NPs, the accumulation of cerium at the roots significantly stunted the root growth. However, these NP treatments did not show significant changes to the distributions of macro-minerals (Mg, K, and Ca) and micro-minerals (Zn and Cu) in the microgreens at the end of the 12-day growth period. The phytotoxic effect of sub-3-nm crystalline ceria nanoparticles on the hydroponic growth of Daikon radish microgreens was studied. The cerium uptake by the plant and its effect on the bioavailability of major macro-minerals and micro-minerals within the plant were examined.

Bioaccumulation and phytotoxicity of ZnO nanoparticles in soil-grown Brassica chinensis L. and potential risks

Zinc oxide nanoparticles (ZnO NPs) widely used have caught the attention of researchers, nevertheless, phytotoxicity, bioaccumulation, and potential risks thereof to the green leafy still have knowledge defects. A pot experiment was intended to cultivate pakchoi (Brassica chinensis L.) following root exposure to ZnO NPs and Zn²⁺. ZnO NPs promoted plant growth and Zn accumulation, formed a dose-dependent effect on chlorophyll and carotenoids, and induced fluctuations in antioxidant enzyme activities and alleviated the oxidative damage of pakchoi. Particularly, 1000 mg kg^-1 ZnO NPs resulted in malondialdehyde (MDA) content of pakchoi shoots that was 87% higher than control. TEM was used to observe ZnO NPs of root cells and found that its possible way to enter the plant was endocytosis. Research on the content of several co-existing nutrients showed that 100 mg kg^-1 ZnO NPs significantly (p < 0.05) promoted the absorption of Ca, P and Fe by pakchoi shoots. In parallel, the hazard quotient (HQ) was used to assess the potential health risk of ZnO NPs.

Environment and food safety: a novel integrative review

Environment protection and food safety are two critical issues in the world. In this review, a novel approach which integrates statistical study and subjective discussion was adopted to review recent advances on environment and food safety. Firstly, a scientometric-based statistical study was conducted based on 4904 publications collected from the Web of Science Core Collection database. It was found that the research on environment and food safety was growing steadily from 2001 to 2020. Interestingly, the statistical analysis of most-cited papers, titles, abstracts, keywords, and research areas revealed that the research on environment and food safety was diverse and multidisciplinary. In addition to the scientometric study, strategies to protect environment and ensure food safety were critically discussed, followed by a discussion on the emerging research topics, including emerging contaminates (e.g., microplastics), rapid detection of contaminants (e.g., biosensors), and environment friendly food packaging materials (e.g., biodegradable polymers). Finally, current challenges and future research directions were proposed.

Effects of ceria nanoparticles and CeCl3 on growth, physiological and biochemical parameters of corn (Zea mays) plants grown in soil

The release of toxic ions from metal-based nanoparticles (NPs) may play an important role in biological effects of NPs. In this life cycle study, physiological and biochemical responses of soil-grown corn (Zea mays) plants exposed to ceria NPs and its ionic counterparts Ce³⁺ ions at 0, 25, 75 and 225 mg Ce/kg were investigated. Both treatments tended to reduce the fresh weight and height of the plants at 28 days after sowing (DAS), and delay silk appearance and finally decrease fruit weight at harvest. Uptake and distribution of some mineral nutrients, Ca, P, Fe, B, Zn and Mn in the plants were disturbed. None of the treatments significantly affected activities of antioxidant enzymes and MDA contents in the roots and leaves at 28 DAS. At 90 DAS, ceria NPs and Ce³⁺ ions disturbed the homeostasis of antioxidative systems in the plants, Ce³⁺ ions at all concentrations provoked significant oxidative damage in the roots and significantly increased MDA levels as compare to the control. The results indicate that the effects of ceria NPs and Ce³⁺ ions on corn plants varied with different growth stages and ceria NPs had similar but less severe impacts than Ce³⁺ ions. Speciation analysis revealed there was mutual transformation between CeO₂ and Ce³⁺ in the soil-plant system. It is speculated that Ce³⁺ ions play a key role in toxicity. To the authors' knowledge, this is the first report of a life cycle study on comparative toxicity of CeO₂ NPs and Ce³⁺ ions on corn plants.