Metabolomics revealing the response of rice (Oryza sativa L.) exposed to polystyrene microplastics

Polycaprolactam microplastics reduce allelopathic potential of Iris pseudacorus via toxic effects on stimulatory bacteria

Many studies have investigated the toxic effects of microplastics (MPs) ingested by aquatic animals, but the effects of MPs that adhere to the roots of macrophytes require further exploration. Thus, the present study investigated the dose-dependent toxic effects of adding 10-500 mg/kg of polycaprolactam microplastics (PCM) on allelopathic cyanobacterial inhibition by a wetland macrophyte due to the influence on rhizosphere bacteria in a pot trial. First, comparisons of sterilized and unsterilized Iris pseudacorus rhizosphere soil showed that the unsterilized soil could enhance the root activity and allelopathic inhibition of Microcystis aeruginosa cyanobacteria. Furthermore, adding 50-100 mg/kg PCM to the unsterilized soil significantly altered the abundances of many types of bacteria, and decreased the root activity and bacterial biodiversity in the rhizosphere. Importantly, PCM changed the secondary metabolites profile in the roots, as well as decreasing production of the allelochemical palmitic acid and the allelopathic potential of I. pseudacorus. Moreover, a dominant strain of functional bacterium AAP51 was identified as an allelopathic promoter, isolated, and successfully inoculated into the sterilized soil. The decomposition of PCM produced the toxic monomer caprolactam in the rhizosphere soil at an average rate of 0.067 mg/kg·d under treatment with 50 mg/kg PCM. Toxicological testing showed that 5 mg/kg caprolactam inhibited the activities of the dominant bacteria and expression of the allelopathic gene FAD2 to weaken the allelopathic effect of I. pseudacorus. Thus, the findings obtained in this study indicate that PCM inhibited the allelopathic potential of the macrophyte due to the release of toxic caprolactam damaging bacteria in the rhizosphere. Consequently, it is necessary to remove MP pollutants from aquatic ecosystems in order to maintain the strong allelopathic potential of macrophytes and efficiently control cyanobacterial blooms.

Biodegradable microplastics affect tomato (Solanum lycopersicum L.) growth by interfering rhizosphere key phylotypes

Biodegradable microplastics (BMPs), which form as biodegradable plastics degrade in agricultural settings, may influence plant growth and soil health. This study investigates the effects of BMPs on tomato growth and the microbial mechanisms involved. A greenhouse experiment applied BMPs-polyhydroxyalkanoate (PHA), polylactic acid (PLA), poly(butylene succinate-co-butylene adipate) (PBSA), and poly(butylene-adipate-co-terephthalate) (PBAT)-to tomato plants. The study analyzed their effects on plant growth, soil properties, and rhizosphere microbial communities. BMP treatments significantly reduced tomato biomass, height, and chlorophyll content compared to the control. PLA0.1 decreased the chlorophyll a/b ratio, while PLA1 increased it. Elemental analysis showed PLA1 increased phosphorus, calcium, and potassium in leaves, whereas all BMPs reduced nitrogen levels. BMPs also altered soil nitrogen and DOC levels, significantly shifting rhizosphere microbial communities, with a notable increase in Betaproteobacteria abundance. Ecological network analysis revealed that BMPs disrupted key microbial modules linked to plant growth. Beneficial modules positively associated with biomass and nutrient uptake were reduced under BMP treatments, whereas harmful microbial taxa in module 3, associated to poor plant health, were promoted. These shifts suggest that BMPs disrupt microbial ecological relationships critical for optimal plant growth. The findings highlight the potential negative impacts of BMPs on tomato growth through changes in microbial dynamics and soil properties.

Assessing the impact of micro and nanoplastics on the productivity of vegetable crops in terrestrial horticulture: a comprehensive review

Micro and nano plastics (MNPs) pollution has emerged as a significant environmental issue in recent years. Plastic contamination in the environment poses risks to both human health and other organisms within the ecosystem. This review discusses the overall impact of MNPs on the performance of vegetable crops, including a global perspective on the topic. Bibliometric analysis reveals that most research on this subject has been concentrated in a few countries, although the number of studies has notably increased in recent years. MNPs accumulate in arable lands due to human activities, often altering the soil's physical, chemical, and biological properties in the rhizosphere. Vegetable crops absorb these MNPs mainly through their roots, leading to accumulation in the edible parts of the plants. Consequently, this results in phytotoxic symptoms and poor growth and development. The phytotoxic effects of MNPs are attributed to genetic and metabolic changes within the plant's cellular structure. Current research on MNPs has been limited to a few vegetable cultivars. Future studies should encompass a broader range of vegetable crops under both laboratory and field conditions to advance this burgeoning field of research. Additionally, examining various types of plastics is essential to comprehensively understanding their impact.

Combined transcriptome and metabolome analysis revealed the toxicity mechanism of individual or combined of microplastic and salt stress on maize

In saline alkaline soils, microplastics inevitably form a combined stress with NaCl to limit crop growth, but the molecular mechanisms of their toxic effects remain vague and inadequate. We analyzed the molecular mechanisms underlying the response of maize seedlings to single or combined stresses of MPs and NaCl by means of combined metabolomic and transcriptomic analyses. MPs and NaCl single or combined stresses reduced plant fresh weight by 36.78 %, 50.65 % and 73.97 %, respectively. Analyses showed 2476 differentially expressed genes (DEGs) and 809 differential metabolites (DMs) for MPs, 2306 DEGs and 901 DMs for NaCl, and 2706 DEGs and 938 DMs for the combined stresses, compared to CK. Single or combined stresses mainly altered amino acid synthesis and phenylpropane biosynthetic metabolic pathways. Stress up-regulated glutamine synthetase (glnA), alanine transaminase (ALT), aspartate aminotransferase (ASP), ornithine carbamoyl transferase (argF), and glycine hydroxymethyl transferase (SHM) genes expression and promotes glutamine, 2-oxoglutarate, glutamate, fumarate, arginine, aspartate, L-isoleucine, L-valine, and serine synthesis. NaCl stimulated phenylpropanoid biosynthesis (tyrosine, 4-coumarate, and ferulate), whereas MPs decreased it. In addition, both individual or combined NaCl and MPs stress increased the expression of cinnamyl-alcohol dehydrogenase (CAD) and cinnamoyl-CoA reductase (CCR) to promote sinapaldehyde synthesis. Our study provides a molecular perspective on the response of crops, such as maize, to individual or combined NaCl and MPs stress.

Coding and non-coding transcripts modulated by transparent and blue PET micro-nanoplastics in Arabidopsis thaliana

To get further insights on the micro-nanoplastic (MNP) effects on plants, the aim of this study was to evaluate the response of hydroponically cultivated Arabidopsis thaliana to the presence of differentially colored polyethylene terephthalate (PET) particles. MNP impacts on the root organ were studied at a molecular level, with a special focus on the role of long non-coding RNAs (lncRNAS) in the regulation of gene expression after PET exposure. MNPs of transparent (Tr-PET) and blue (Bl-PET) material at environmentally realistic concentration caused a significant reduction in root length, while only Bl-PET significantly reduced rosette area. MNPs induced oxidative stress markers. Tr-PET upregulated genes involved in signaling of xenobiotics, whereas Bl-PET scarcely affected root transcriptomic profile, activating few gene categories for abiotic stresses. Regarding hormones, genes involved in ABA response were repressed, while brassinosteroid-related genes were differentially regulated by Tr-PET. Both MNPs, but especially Tr-PET, upregulated major latex protein-related genes. Plant molecular response to MNPs was linked to differential abundance of lncRNAs on both comparisons. Tr-PET affected the expression of much more lncRNAs than bl-PET (80 and 11 respectively). These lncRNAs were predicted to interact with several repressed protein-coding genes (i.e. glucosyltransferase UGT2, oxidative stress genes etc.), with possible effects on their regulation. A lncRNA (AT1G09297) interacted with CYP81D8, a key gene of cytochrome P450 gene family involved in xenobiotics detoxification. Two lncRNAs interacted with two members of repressed HSP (HSP90 and HSP17.4) family. Finally, genes involved in redox detoxification and stress responses were inhibited by the interaction with two microplastics-regulated lncRNAs. These data highlighted the need of investigating non-coding RNAs in the future in addition to the mostly studied protein coding transcriptome.

Flavonoids Mitigate Nanoplastic Stress in Ginkgo biloba

Microplastics/nanoplastics are a top global environmental concern and have stimulated surging research into plant-nanoplastic interactions. Previous studies have examined the responses of plants to nanoplastic stress at various levels. Plant-specialized (secondary) metabolites play crucial roles in plant responses to environmental stress, whereas their roles in response to nanoplastic stress remain unknown. Here, we systematically examined the physiological and biochemical responses of Ginkgo biloba, a species with robust metabolite-driven defenses, to polystyrene nanoplastics (PSNPs). PSNPs negatively affected seedling growth and induced phytotoxicity, oxidative stress, and nuclear damage. Notably, PSNPs caused significant flavonoid accumulation, which enhances plant tolerance and detoxification against PSNP stress. To determine whether this finding is universal in plants, we subjected Arabidopsis, poplar, and tomato to PSNP stress and verified the common response of enhanced flavonoids across these species. To further confirm the role of flavonoids, we employed genetic transformation and staining techniques, validating the importance of flavonoids in mitigating excessive oxidative stress induced by NPs. Matrix analysis of transgenic plants with enhanced flavonoids further demonstrated altered downstream pathways, allocating more energy towards resilience against nanoplastic stress. Collectively, our results reveal the flavonoid multifaceted roles in enhancing plant resilience to nanoplastic stress, providing new knowledge about plant responses to nanoplastic contamination.

Toxicological effects and molecular metabolic of polystyrene nanoplastics on soybean (Glycine max L.): Strengthening defense ability by enhancing secondary metabolisms

Nanoplastics, as emerging pollutants, have attracted worldwide concern for their possible environmental dangers. The ingestion and accumulation of nanoplastics in crops can contaminate the food chain and have unintended consequences for human health. In this study, we revealed the effects of polystyrene nanoplastics (PS-NPs; 80 nm) at different concentrations (0, 10, 100 mg L-1) on soybean (Glycine max L.) seedling growth, antioxidant enzyme system and secondary metabolism. Using laser confocal microscopy, we demonstrated that the absorption and translocation of PS-NPs in soybean. Plant growth inhibition was observed by changes in plant height, root length, and leaf area after 7 days of exposure to PS-NPs. The effect of PS-NPs on photosynthetic characteristics was reflected by a significant reduction in total chlorophyll content at 10 mg L-1. Activation of the antioxidant system was observed with increased malondialdehyde (MDA) content, and elevated activities of superoxide dismutase (SOD) and catalase (CAT). Non-targeted metabolomics analysis identified a total of 159 secondary metabolites, and exposure to 10 and 100 mg L-1 PS-NPs resulted in the production of 61 and 62 differential secondary metabolites. Metabolomics analysis showed that PS-NPs treatment altered the secondary metabolic profile of soybean leaves through the biosynthesis pathways of flavonoid, flavone flavonol, and isoflavones, which is expected to provide new insights into the tolerance mechanisms of plants to nanoplastics. Overall, the results of this study deepen our understanding of the negative impacts of nanoplastics in agricultural systems, which is crucial for assessing the risks of nanoplastics to ecological security.

Metabolomics combined with physiology and transcriptomics reveal the regulation of key nitrogen metabolic pathways in alfalfa by foliar spraying with nano-selenium

Selenium promotes plant growth and improves nutritional quality, and the role of nano-selenium in alfalfa in regulating nutritional quality is unknown. In this study, using the 15N labeling method, it was found that nano-selenium could promote plant nitrogen metabolism and photosynthesis by increasing the light energy capture capacity and the activities of key enzymes of the nitrogen metabolism process, leading to an increase in alfalfa nitrogen accumulation and dry matter content. The transcriptome and metabolome revealed that nano-selenium mainly affected the pathways of 'biosynthesis of amino acids', 'starch and sucrose metabolism', 'pentose and glucuronate interconversions', 'pentose phosphate pathway', and 'flavonoid biosynthesis'. At the early stage of nano-selenium treatment, the nitrogen metabolism, sugar metabolism, and flavonoid metabolism pathways were regulated by modulating the expression of genes such as NR, Nir, GS, GOGAT, E3.1.1.11, adh, CHS, FLS, etc., which increased the amount of L-glutamic, L-histidine, glycerone-P, coniferin, naringenin chalcone, and other beneficial substances, thus promoting the acceleration of nitrogen accumulation by plants. In summary, this study provides a better understanding of the mechanisms by which nano-selenium regulates key nitrogen metabolic pathways in alfalfa.

Unveiling the mechanism of micro-and-nano plastic phytotoxicity on terrestrial plants: A comprehensive review of omics approaches

Micro-and-nano plastics (MNPs) are pervasive in terrestrial ecosystems and represent an increasing threat to plant health; however, the mechanisms underlying their phytotoxicity remain inadequately understood. MNPs can infiltrate plants through roots or leaves, causing a range of toxic effects, including inhibiting water and nutrient uptake, reducing seed germination rates, and impeding photosynthesis, resulting in oxidative damage within the plant system. The effects of MNPs are complex and influenced by various factors including size, shape, functional groups, and concentration. Recent advancements in omics technologies such as proteomics, metabolomics, transcriptomics, and microbiomics, coupled with emerging technologies like 4D omics, phenomics, spatial transcriptomics, and single-cell omics, offer unprecedented insight into the physiological, molecular, and cellular responses of terrestrial plants to MNPs exposure. This literature review synthesizes current findings regarding MNPs-induced phytotoxicity, emphasizing alterations in gene expression, protein synthesis, metabolic pathways, and physiological disruptions as revealed through omics analyses. We summarize how MNPs interact with plant cellular structures, disrupt metabolic processes, and induce oxidative stress, ultimately affecting plant growth and productivity. Furthermore, we have identified critical knowledge gaps and proposed future research directions, highlighting the necessity for integrative omics studies to elucidate the complex pathways of MNPs toxicity in terrestrial plants. In conclusion, this review underscores the potential of omics approaches to elucidate the mechanisms of MNPs-phytotoxicity and to develop strategies for mitigating the environmental impact of MNPs on plant health.

Metabolic profiles and protein expression responses of Pacific oyster (Crassostrea gigas) to polystyrene microplastic stress

The underlying toxicity mechanisms of microplastics on oysters have rarely been explored. To fill this gap, the present study investigated the metabolic profile and protein expression responses of oysters to microplastic stress through metabolomics and biochemical analyses. Oysters were exposed to microplastics for 21 days, and the results indicated that the microplastics induced oxidative stress, with a significant decrease in SOD activity in the 0.1 mg/L exposure group. Metabolomics revealed that exposure to microplastics disturbed many metabolic pathways, such as amino acid metabolism, lipid metabolism, biosynthesis of amino acids, aminoacyl-tRNA biosynthesis, and that different concentrations of microplastics induced diverse metabolomic profiles in oysters. Overall, the current study provides new reference data and insights for assessing food safety and consumer health risks caused by microplastic contamination.

Microplastics in Agricultural Crops and Their Possible Impact on Farmers' Health: A Review

The indiscriminate use of plastic products and their inappropriate management and disposal contribute to the increasing presence and accumulation of this material in all environmental zones. The chemical properties of plastics and their resistance to natural degradation lead over time to the production of microplastics (MPs) and nanoplastics, which are dispersed in soil, water, and air and can be absorbed by plants, including those grown for food. In agriculture, MPs can come from many sources (mulch film, tractor tires, compost, fertilizers, and pesticides). The possible effects of this type of pollution on living organisms, especially humans, increase the need to carry out studies to assess occupational exposure in agriculture. It would also be desirable to promote alternative materials to plastic and sustainable agronomic practices to protect the safety and health of agricultural workers.

Understanding the possible cellular responses in plants under micro(nano)-plastic (MNPs): Balancing the structural harmony with functions

The harmful impacts of micro(nano)-plastics (MNPs) on plants have gained significant attention in the last decades. Plants have a greater tendency to aggregate positively charged (+ve) MNPs on leaf surfaces and root tips, and it can be more challenging to enter the plant body than the negatively charged (-ve) MNPs. MNPs <20 nm can directly cross the cell wall and enter mainly via leaf stomata and root crack portion. Additionally, plants with aerenchyma tissue or higher water requirement might be more vulnerable to MNPs as well as environmental factors also affected MNPs uptake like porosity and structure (i.e. crack of soil) of soil, wind speed, etc. The subsequent translocation of MNPs hamper regular morphological, physiological, and biochemical functions by causing oxidative stress, altering several plant metabolic pathways, reducing the rate of photosynthesis and nutrient intake, etc. These induce cellular toxicity and chromosomal alteration; as a result, the total biomass and productivity reduce vigorously. However, there is a knowledge gap regarding MNPs' uptake by plants and related variables affecting phytotoxicity at the omics levels. So, the present literature review represents a comprehensive theoretical framework that includes genomics, transcriptomics, miRNAomics, proteomics, metabolomics, and ionomics/metallomics, which is established to understand the effects of MNPs on plants at the molecular level. As well as it will also help in further studies of the research community in the future because this field is still in the preliminary stages due to a lack of study.

Effects of polystyrene microplastics on the growth and metabolism of highland barley seedlings based on LC-MS

Microplastics are widely present in the environment and can adversely affect plants. In this paper, the effects of different concentrations of microplastics on physiological indices and metabolites of highland barley were investigated for the first time using a metabolomics approach, and revealed the response mechanism of barley seedlings to polystyrene microplastics (PS-MPs) was revealed. The results showed that the aboveground biomass of highland barley exposed to low (10 mg/L) and medium (50 mg/L) concentrations of PS-MPs increased by 32.2% and 48.2%, respectively. The root length also increased by 16.4% and 21.6%, respectively. However, the aboveground biomass of highland barley exposed to high (100 mg/L) concentrations of PS-MPs decreased by 34.8%, leaf length by 20.7%, and root length by 25.9%. Microplastic exposure increased the levels of antioxidant activity, suggesting that highland barley responds to microplastic stress through oxidative stress. Metabolome analysis revealed that the contents of 4 metabolites increased significantly with increasing PS-MPs concentration in positive ionmode, while the contents of 8 metabolites increased significantly with increasing PS-MPs concentration in negative ionmode (P < 0.05), including prunin, dactylorhin E, and schisantherin B. Additionally, PS-MPs significantly interfered with highland barley flavonoid biosynthesis, pyrimidine metabolism, purine metabolism, fatty acid biosynthesis, and phenylpropanoid biosynthesis metabolic pathways. This study provides a new theoretical basis for a deeper understanding of the effects of different concentrations of PS-MPs on highland barley.

Microbial strategies for effective microplastics biodegradation: Insights and innovations in environmental remediation

Microplastics (MPs), diminutive yet ubiquitous fragments arising from the degradation of plastic waste, pervade environmental matrices, posing substantial risks to ecological systems and trophic dynamics. This review meticulously examines the origins, distribution, and biological impacts of MPs, with an incisive focus on elucidating the molecular and cellular mechanisms underpinning their toxicity. We highlight the indispensable role of microbial consortia and enzymatic pathways in the oxidative degradation of MPs, offering insights into enhanced biodegradation processes facilitated by innovative pretreatment methodologies. Central to our discourse is the interplay between MPs and biota, emphasizing the detoxification capabilities of microbial metabolisms and enzymatic functions in ameliorating MPs' deleterious effects. Additionally, we address the practical implementations of MP biodegradation in environmental remediation, advocating for intensified research to unravel the complex biodegradation pathways and to forge effective strategies for the expeditious elimination of MPs from diverse ecosystems. This review not only articulates the pervasive challenges posed by MPs but also positions microbial strategies at the forefront of remedial interventions, thereby paving the way for groundbreaking advancements in environmental conservation.

Impact of microplastics on plant physiology: A meta-analysis of dose, particle size, and crop type interactions in agricultural ecosystems

The increasing prevalence of plastic pollution has led to widespread environmental concerns, particularly with microplastics (MPs) that persist in various ecosystems. As MPs accumulate in terrestrial environments, their potential impact on plant health and agricultural productivity has become a growing area of focus. This study presents a comprehensive meta-analysis evaluating the effects of MPs on plant physiological and biochemical parameters, synthesizing data from 37 studies comprising 2886 observations. Our findings indicate that MPs significantly decrease plant biomass by 13 % (95 % CI: 7-19 %) and chlorophyll content by 28 % (95 % CI: 23-34 %), impairing crop growth and quality. Notably, higher doses and smaller MP particle sizes exert more pronounced inhibitory effects, particularly on root activity and biomass, while larger MPs predominantly damage plant roots. Furthermore, MPs were found to significantly increase oxidative stress in plants, evidenced by a 20 % rise in oxidative damage (95 % CI: 15-25 %) and a 14 % increase in antioxidant capacity (95 % CI: 8-19 %). This study highlights intricate interactions between MP type, particle size, dose, and plant species, with particle size having a greater impact than dose. This study emphasizes the importance of accounting for crop diversity and environmental factors to fully elucidate the potential risks posed by MP pollution to agricultural ecosystems.

Mechanistic insight into interactive effect of microplastics and arsenic on growth of rice (Oryza sativa L.) and soil health indicators

Microplastics (MPs) pollution has recently become a major concern for agroecosystems. The interplay between MPs, and heavy metal(loid)s in the soil can intensify the risks to plant growth and human health. The current study investigated the interactive effects of arsenic (As) and biodegradable and petroleum-based conventional MPs on rice growth, As bioavailability, soil bacterial communities, and soil enzyme activities. As-contaminated soil (5 mg kg-1) was treated with conventional MPs i.e., polystyrene (PS) and polyethylene (PE) and biodegradable MPs i.e., polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) at 0.1 % and 1 % rates. In a pot experiment, rice plants were cultivated in soil co-contaminated with As and MPs. PLA-MPs exhibited significant interactions with As, increasing its bioavailability and impairing rice plant growth by enhancing plant oxidative stress. The results illustrated that T2 treatment (PLA-MPs @ 1 % + As 5 mg kg-1) significantly decreased the root and shoot lengths, root and shoot dry weights as well as the rates of photosynthesis, transpiration, intercellular CO2, and stomatal conductance in rice plants. Biodegradable PLA-MPs @ 1 % resulted in increased uptake of As in rice roots, stems, and leaves by 13.4 %, 38.9 %, and 20.6 %, respectively. In contrast, conventional PE-MPs @ 1 % showed contradictory results with As uptake declined by 2.2 %, 5.1 %, and 9.9 % in rice roots, stem and leaves. Soil enzyme kinetics showed that biodegradable MPs increased the activities of soil catalase, dehydrogenase, and phytase enzymes, whereas both conventional PS and PE-MPs decreased their activities. Moreover, As and PLA-MPs combined stress altered soil bacterial communities by increasing the relative abundance of Protobacteria, Acidobacteria, Chloroflexi, and Firmicutes phyla by 49 %, 29 %, 82 %, and 57 %, respectively. This study provides new insights into MPs-As interactions in soil-plant system and ecological risks associated with their coexistence.

Impacts of plastic pollution on soil-plant properties and greenhouse gas emissions in wetlands: A meta-analysis

Plastic pollution in wetlands has recently emerged as an urgent environmental problem. However, the impacts of plastic contamination on soil-plant properties and greenhouse gas (GHG) emissions in wetlands remain unclear. Thus, this study conducted a meta-analysis based on 44 study sites to explore the influence of plastic pollution on soil physicochemical variables, soil microorganisms, enzyme activity, functional genes, plant characteristics, and GHG emissions (CO2, CH4, and N2O) in different wetland types. Based on the collected dataset, the plastic pollution significantly increased soil organic matter and organic carbon by on average 28.9 % and 34.2 %, respectively, while decreased inorganic nutrient elements, bacteria alpha diversity and enzyme activities by an average of 5.9 -14.2 %. The response of bacterial abundance to plastic pollution varied depending on phylum classes. Plant biomass and photosynthetic efficiency were decreased by an average of 12.8 % and 18.4 % due to plastic pollution. The concentration and exposure time of plastics play a key role in influencing the soil and plant properties in wetlands. Furthermore, plastic exposure notably increased the abundance of the functional genes related to C degradation and the ammonia oxidizing microorganisms, and the consequent CO2 and N2O emissions (with effect sizes of 2.10 and 1.94, respectively). We also found that plastic concentrations and exposure duration affected the wetland soil-plant system. Our results might be helpful to design further investigations on plastic effects and develop appropriate measures for mitigating plastic pollution in wetlands.

Metabolomics combined with physiology reveal how white clover (Trifolium repens L.) respond to 6PPD stress

As a ubiquitous tire antioxidant, N-(1,3-Dimethyl-butyl)-N'-phenyl-p-phenylene- diamine (6PPD) exists widely in various environmental media and has been detected at high levels in the environment. However, the effects of 6PPD on plants are still poorly understood. In this study, a hydroponic experiment was carried out to investigate the response of white clover (Trifolium repens L.) stressed by 6PPD on physiology and metabolomics. The results indicated that the length of stem and root, as well as biomass were significantly reduced after 500 μg L-1 6PPD treatment. Photosynthetic performances including photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) and chlorophyll content of leaves decreased in all treatments except 500 μg L-1 of 6PPD. The malondialdehyde (MDA) content in the shoot of white clover increased by 66.33 % when exposed to 500 μg L-1 of 6PPD compared to control group (CK). Hydrogen peroxide and superoxide anion presented a U-shape trend and began to increase at 500 μg L-1. Besides, peroxidase and catalase significantly decreased compared to CK after exposure to 500 μg L-1. Metabolic analysis of clover showed that 6PPD treatment induced changes in 10 metabolic pathways of white clover. Metabolites were significantly down-regulated after exposure to 500 μg L-1 in shoot, while significantly down-regulated in all treatment groups except 500 μg L-1 in root. These findings may provide a novel perspective for phytotoxicity assessment and phytoremediation of 6PPD.

Metabolomics reveals the size effect of microplastics impeding membrane synthesis in rice cells

The global-scale production of plastics has led to a significant accumulation in the environment, and it has become a major stressor to environmental sustainability, agricultural crops, and human health. Here we report the particle size effect of polystyrene (PS, typically microplastic) on the impact on rice suspension cells. This study used PS of different particle sizes (30 nm, 200 nm, and 2 μm) in a three-day co-culture experiment, the results showed that 30 nm, 200 nm, and 2 μm PS at the same concentration (100 μg/mL) caused 4.6 %, 55.8 %, and 66.4 % decrease in rice suspension cell viability, respectively. Furthermore, a substantial reduction in protein content, amounting to 26.53 % and 48.47 %, was observed in cells treated with 200 nm and 2 μm PS, and the DNA and RNA content of rice suspension cells also decreased substantially at 100 μg/mL PS. Non-targeted metabolomics analyses showed that PS disrupted fatty acid biosynthesis with a clear size effect, wherein 2 μm PS caused a decrease of 64.9 % in hexadecanoic acid content. Consequently, this finding provides valuable perspectives on the potential ecotoxicity of microplastics at the single-cell level of rice and will facilitate the formulation of an environmental management program specifically tailored for addressing the challenges posed by microplastics.

Combined effects of polyamide microplastic and sulfamethoxazole in modulating the growth and transcriptome profile of hydroponically grown rice (Oryza sativa L.)

The use of reclaimed water from wastewater treatment plants for irrigation has a risk of introducing micropollutants such as microplastics (MPs) and antimicrobials (AMs) into the agroecosystem. This study was conducted to investigate the effects of single and combined treatment of 0.1 % polyamide (PA ∼15 μm), and varying sulfamethoxazole (SMX) levels 0, 10, 50, and 150 mg/L on rice seedlings (Oryza sativa L.) for 12 days. The study aimed to assess the impact of these contaminants on the morphological, physiological, and biochemical parameters of the rice plants. The findings revealed that rice seedlings were not sensitive to PA alone. However, SMX alone or in combination with PA, significantly inhibited shoot and root growth, total biomass, and affected photosynthetic pigments. Higher concentrations of SMX increased antioxidant enzyme activity, indicating oxidative stress. The roots had a higher SMX content than the shoots, and the concentration of minerals such as iron, copper, and magnesium were reduced in roots treated with SMX. RNA-seq analysis showed changes in the expression of genes related to stress, metabolism, and transport in response to the micropollutants. Overall, this study provides valuable insights on the combined impacts of MPs and AMs on food crops, the environment, and human health in future risk assessments and management strategies in using reclaimed water.

Unveiling the impacts of microplastic pollution on soil health: A comprehensive review

Soil contamination by microplastics (MPs) has emerged as a significant global concern. Although traditionally associated with crop production, contemporary understanding of soil health has expanded to include a broader range of factors, including animal safety, microbial diversity, ecological functions, and human health protection. This paradigm shifts underscores the imperative need for a comprehensive assessment of the effects of MPs on soil health. Through an investigation of various soil health indicators, this review endeavors to fill existing knowledge gaps, drawing insights from recent studies conducted between 2021 and 2024, to elucidate how MPs may disrupt soil ecosystems and compromise their crucial functions. This review provides a thorough analysis of the processes leading to MP contamination in soil environments and highlights film residues as major contributors to agricultural soils. MPs entering the soil detrimentally affect crop productivity by hindering growth and other physiological processes. Moreover, MPs hinder the survival, growth, and reproductive rates of the soil fauna, posing potential health risks. Additionally, a systematic evaluation of the impact of MPs on soil microbes and nutrient cycling highlights the diverse repercussions of MP contamination. Moreover, within soil-plant systems, MPs interact with other pollutants, resulting in combined pollution. For example, MPs contain oxygen-containing functional groups on their surfaces that form high-affinity hydrogen bonds with other pollutants, leading to prolonged persistence in the soil environment thereby increasing the risk to soil health. In conclusion, we succinctly summarize the current research challenges related to the mediating effects of MPs on soil health and suggest promising directions for future studies. Addressing these challenges and adopting interdisciplinary approaches will advance our understanding of the intricate interplay between MPs and soil ecosystems, thereby providing evidence-based strategies for mitigating their adverse effects.

Single and combined effect of polyethylene microplastics (virgin and naturally aged) and cadmium on pakchoi (Brassica rapa subsp. chinensis) under different growth stages

To protect agro-systems and food security, study on the effect of microplastics and heavy metals on edible plants is of great significance. Existing studies mostly used virgin microplastics to evaluate their effects on plants, effects of naturally aged microplastics and their combined effects with heavy metals are rarely explored. In this study, single and combined effect of polyethylene microplastics (PE, both virgin and naturally aged) and cadmium (Cd) on pakchoi under seedling and mature stages were analyzed from perspectives of growth inhibition, oxidative damage, nutrition content and soil enzyme activities. Results showed that inhibiting effects of naturally aged PE (PEa) on the growth of pakchoi were stronger than virgin PE (PEv), whereas co-contamination of PEa and Cd was less toxic than that of PEv and Cd. The co-contamination of PE and Cd could inhibit pakchoi dry biomass by over 85 %. Both single and combined contamination of PE and Cd promoted soil fluorescein diacetate hydrolase (FDA) activities, which were 1.11 to 2.04 times of that in control group. Soluble sugar contents under co-contamination of PEa and Cd were 14 % to 22 % higher than those in control group. PEa and PEv showed different effects on oxidative damage of pakchoi. Compared with PEv, catalase (CAT) activities were more sensitive with PEa, whereas PEa had lower effect on superoxide dismutase (SOD) activities. The response of pakchoi to PE and Cd changed with growth stage. Chlorophyll contents in pakchoi under seedling stage were generally higher than those under mature stage. For Cd contaminated soils, PE benefited pakchoi growth under seedling stage, i.e. antagonistic effect between Cd and PE but hindered their growth under mature stage, i.e. synergistic effect. The results unraveled here emphasized PE, especially PEa, could trigger negative effects on agro-systems, whereas PE could be beneficial for heavy metal contaminated agro-systems under specific situations.

Environmental concentrations of 6PPD and 6PPD-Q cause oxidative damage and alter metabolism in Eichhornia crassipes

N-(1,3-dimethylbutyl)-N '-phenyl-p-phenylenediamine (6PPD) and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) are ubiquitous in the environment and can cause toxicity to aquatic animals. However, research on the toxicological effects of 6PPD and 6PPD-Q on aquatic plants remains limited. The present study investigated the physiological, biochemical, and metabolic responses of the floating aquatic plant Eichhornia crassipes (E. crassipes) to environmentally relevant concentrations (0.1, 1, and 10 μg·L-1) of 6PPD and 6PPD-Q. We found that 6PPD and 6PPD-Q elicited minimal effects on plant growth, but 6PPD induced a concentration-dependent decrease in the content of photosynthetic pigments. Low doses (0.1 μg·L-1 and 1 μg·L-1) of 6PPD-Q significantly elevated Reactive Oxygen Species (ROS) content in E. crassipes roots, indicating oxidative damage. Furthermore, 6PPD-Q induced a more pronounced osmotic stress compared to 6PPD. Metabolic analyses revealed that carbohydrates were significantly altered under 6PPD and 6PPD-Q treatments. The findings of this study enhance the understanding of the environmental risks posed by 6PPD and 6PPD-Q to plants and reveal the potential mechanisms of phytotoxicity.

Microplastics and nanoplastics in soil: Sources, impacts, and solutions for soil health and environmental sustainability

The present review discusses the growing concern of microplastics (MPs) and nanoplastics (NPs) in soil, together with their sources, concentration, distribution, and impact on soil microorganisms, human health, and ecosystems. MPs and NPs can enter the soil through various pathways, such as agricultural activities, sewage sludge application, and atmospheric deposition. Once in the soil, they can accumulate in the upper layers and affect soil structure, water retention, and nutrient availability. The presence of MPs and NPs in soil can also have ecological consequences, acting as carriers for pollutants and contaminants, such as heavy metals and persistent organic pollutants. Additionally, the leaching of chemicals and additives from MPs and NPs can pose public health risks through the food web and groundwater contamination. The detection and analyses of MPs and NPs in soil can be challenging, and methods involve spectroscopic and microscopy techniques, such as Fourier-transform infrared spectroscopy and scanning electron microscopy. To mitigate the presence and effects of MPs and NPs in soil, it is essential to reduce plastic waste production, improve waste management practices, and adopt sustainable agricultural practices. Effective mitigation measures include implementing stricter regulations on plastic use, promoting biodegradable alternatives, and enhancing recycling infrastructure. Additionally, soil amendments, such as biochar and compost, can help immobilize MPs and NPs, reducing their mobility and bioavailability. This review article aims to provide a comprehensive understanding of these emerging environmental issues and identify potential solutions to alleviate their impact on soil health, ecosystem functioning, and community health.

From Flourish to Nourish: Cultivating Soil Health for Sustainable Floriculture

Despite its rapid growth and economic success, the sustainability of the floriculture industry as it is presently conducted is debatable, due to the huge environmental impacts it initiates and incurs. Achieving sustainability requires joint efforts from all stakeholders, a fact that is often neglected in discussions that frequently focus upon economically driven management concerns. This review attempts to raise awareness and collective responsibility among the key practitioners in floriculture by discussing its sustainability in the context of soil health, as soil is the foundation of agriculture systems. Major challenges posed to soil health arise from soil acidification and salinization stimulated by the abusive use of fertilizers. The poisoning of soil biota by pesticide residues and plastic debris due to the excessive application of pesticides and disposal of plastics is another significant issue and concern. The consequence of continuous cropping obstacles are further elucidated by the concept of plant-soil feedback. Based on these challenges, we propose the adoption and implementation of several sustainable practices including breeding stress-resistant and nutrient-efficient cultivars, making sustainable soil management a goal of floriculture production, and the recycling of plastics to overcome and mitigate the decline in soil health. The problems created by flower waste materials are highlighted and efficient treatment by biochar synthesis is suggested. We acknowledge the complexity of developing and implementing the proposed practices in floriculture as there is limited collaboration among the research and operational communities, and the policymakers. Additional research examining the impacts the floriculture industry has upon soils is needed to develop more sustainable production practices that can help resolve the current threats and to bridge the understanding gap between researchers and stakeholders in floriculture.

Microplastics in the soil-water-food nexus: Inclusive insight into global research findings

Nuisance imposed by biotic and abiotic stressors on diverse agroecosystems remains an area of focus for the scientific fraternity. However, emerging contaminants such as microplastics (MP) have imposed additional dimension (alone or in combinations with other stressors) in agroecosystems and keep escalating the challenges to achieve sustainability. MP are recognized as persistent anthropogenic contaminants, fetch global attention due to their unique chemical features that keeps themselves unresponsive to the decaying process. This review has been theorized to assess the current research trends (along with possible gap areas), widespread use of MP, enhancement of the harshness of heavy metals (HMs), complex interactions with physico-chemical constituents of arable soil, accumulation in the edible parts of field crops, dairy products, and other sources to penetrate the food web. So far, the available review articles are oriented to a certain aspect of MP and lack a totality when considered from in soil-water-food perspective. In short, a comprehensive perspective of the adverse effects of MP on human health has been assessed. Moreover, an agro-techno-socio-health prospective-oriented critical assessment of policies and remedial measures linked with MP has provided an extra edge over other similar articles in influential future courses of research.

Low-frequency ultrasound assisted contact-electro-catalysis for efficient inactivation of Microcystis aeruginosa

Frequent cyanobacterial blooms pose a serious threat to the aquatic ecosystem and human health, so developing an efficient algae removal method is a long-term goal for bloom management. Current technologies for algal bloom control need urgent improvement in terms of algicide recovery, eco-friendliness and cost. Here we propose a contact-electro-catalytic method, using polytetrafluoroethylene (PTFE) film as a reusable catalyst. This contact-electro-catalytic approach involves the generation of reactive oxygen species (e.g., O2•-, HO•, 1O2 and H2O2) through water-PTFE contact electrification under the low-frequency ultrasonic waves, facilitating the inactivation of algae. The removal rate of the cyanobacterium Microcystis aeruginosa (M. aeruginosa) exposured to the water-PTFE contact-electro-catalytic system is almost five times greater than that of ultrasound alone after 5 h. A mechanistic investigation revealed that the contact-electro-catalytic system damaged the photosynthetic activity, antioxidant system and membrane integrity of the cells. Additionally, LC-MS metabolomic analysis indicated that this system caused substantial significant disruptions in the TCA cycle, amino acid metabolism, purine metabolism and phospholipid metabolism. Three-dimensional fluorescence spectroscopy suggested contact-electro-catalysis could further availably degrade the organic matter. We anticipate that this method can provide an eco-friendly, highly efficient and economic approach for effective control of harmful algal blooms.

Visual observation of polystyrene nano-plastics in grape seedlings of Thompson Seedless and assessing their effects via transcriptomics and metabolomics

Micro/nano-plastics (MNPs) are emerging non-point source pollutants that have garnered increasing attention owing to their threat to ecosystems. Studies on the effects of MNPs on horticultural crops are scarce. Specifically, whether MNPs can be absorbed and transported by grapevines have not been reported. To fill this gap, we added polystyrene nanoplastics (PS-NPs, 100 nm) to a hydroponic environment and observed their distribution in grape seedlings of Thompson Seedless (TS, Vitis vinifera L.). After 15 d of exposure, plastic nanospheres were detected on the cell walls of the roots, stems, and leaves using confocal microscopy and scanning electron microscopy. This indicated that PS-NPs can also be absorbed by the root system through the epidermis-cortex interface in grapevines and transported upward along the xylem conduit. Furthermore, we analyzed the molecular response mechanisms of TS grapes to the PS-NPs. Through the measurement of relevant indicators and combined omics analysis, we found that plant hormone signal transduction, flavonoid and flavonol biosynthesis, phenylpropanoid biosynthesis, and MAPK signaling pathway biosynthesis played crucial roles in its response to PS-NPs. The results not only revealed the potential risk of MNPs being absorbed by grapevines and eventually entering the food chain but also provided valuable scientific evidence and data for the assessment of plant health and ecological risk.

Characteristics of biofilms on polylactic acid microplastics and their inhibitory effects on the growth of rice seedlings: A comparative study of petroleum-based microplastics

Increasing evidence highlights the negative effects of microplastics (MPs) on crops and bio-based plastics offer an alternative to conventional plastics. However, there is limited knowledge on the impacts and mechanisms of bio-based MPs on crop physiology. In this study, bio-based polylactic acid (PLA) and petroleum-based MPs [polyamide (PA) and polypropylene (PP)] were added to hydroponic cultures planted with rice (Oryza sativa L.) seedlings to assess their toxicity. Compared to PA and PP MPs, PLA MPs experienced greater aging after 28 days of exposure, and their surfaces were loaded with more rod-shaped microorganisms with potential plastic degradation ability, such as Proteobacteria and Bacteroidota, which competed with rice seedlings for carbon and nitrogen sources for self-multiplication, thus altering the carbon fixation and nitrogen cycling processes during rice seedling growth. Down-regulation of amino acid and lipid metabolisms in the PLA treatment inhibited the normal synthesis of chlorophyll in rice seedling leaves. Consequently, decreases in the biomass and height of rice seedling roots and shoots were observed in the PLA MP treatment. This study provides evidence that bio-based MPs may have a more severe impact on crop growth than petroleum-based MPs.

Microplastic and Nanoplastic in Crops: Possible Adverse Effects to Crop Production and Contaminant Transfer in the Food Chain

With the increasing amounts of microplastic (MP) deposited in soil from various agricultural activities, crop plants can become an important source of MP in food products. The last three years of studies gave enough evidence showing that plastic in the form of nanoparticles (<100 nm) can be taken up by the root system and transferred to aboveground plant parts. Furthermore, the presence of microplastic in soil affects plant growth disturbing metabolic processes in plants, thus reducing yields and crop quality. Some of the adverse effects of microplastic on plants have been already described in the meta-analysis; however, this review provides a comprehensive overview of the latest findings about possible adverse effects and risks related to wide microplastic occurrence in soil on crop production safety, including topics related to changes of pesticides behavior and plant pathogen spreading under the presence MP and possibly threaten to human health.

Toxicological effects of di(2-ethylhexyl)phthalate on dandelions: Insights into physiological, metabolic, and molecular docking perspectives

Di(2-ethylhexyl)phthalate (DEHP) is one of the most widely used plasticizers in plastic manufacturing. However, the toxicological effects of DEHP on dandelions remain poorly understood. This study comprehensively analyzed and explored the response mechanisms of dandelions to 1, 10, 50, and 100 mg L-1 DEHP influencing the morphophysiological growth, metabolomics, and molecular docking. DEHP reduced chlorophyll synthesis, inhibited plant growth, and induced oxidative-state-associated stress, which was manifested by the excessive production of reactive oxygen species, an increase in antioxidant enzyme activities, and enhanced synthesis of some osmoregulatory compounds, including proline and soluble protein. An analysis of the integrated biological response index showed that the toxicity was dose-dependent. Molecular docking demonstrated that DEHP could bind stably to three enzymes, and the binding energy was peroxidase (POD) > catalase (CAT) > superoxide dismutase (SOD). Metabolomics revealed that metabolite abundance and metabolic pathways were altered by DEHP, with 88 and 72 primary metabolites identified in shoots and roots, respectively. Amino acid, sugar, and organic acid metabolism were severely disturbed, with the most significant effects being on carbohydrate metabolism, valine, leucine, and isoleucine biosynthesis. Our study elucidated the influence of DEHP exposure on dandelions, providing new insights into the toxicity mechanisms and toxicological risk assessment.

Toxicity of Moxifloxacin on the Growth, Photosynthesis, Antioxidant System, and Metabolism of Microcystis aeruginosa at Different Phosphorus Levels

Moxifloxacin (MOX), a widely used novel antibiotic, may pose ecological risks at its actual environmental concentrations, as has been detected in aquatic systems. However, its ecotoxicity to aquatic organisms and regulatory mechanisms of phosphorus in eutrophic aqueous environments are still limited. This study aimed to analyze its physiological and biochemical parameters, including cellular growth, chlorophyll fluorescence, photosynthetic pigments, oxidative stress biomarkers, and metabolomics to elucidate the toxicity induced by environmental concentrations of MOX in Microcystis aeruginosa at different phosphorus levels. The results revealed that the EC50 values of MOX on M. aeruginosa at different phosphorus concentrations were 8.03, 7.84, and 6.91 μg/L, respectively, indicating MOX toxicity was exacerbated with increasing phosphorus levels. High phosphorus intensified the suppression of chlorophyll fluorescence and photosynthetic pigments, while activating the antioxidant enzyme, indicating severe peroxidation damage. Metabolomic analysis showed MOX induced different discriminating metabolites under different phosphorus levels, and perturbed more biological pathways at higher phosphorus concentrations, such as starch and sucrose metabolism, pyrimidine metabolism, and glycerolipid metabolism. This indicates that phosphorus plays an important role in regulating metabolism in M. aeruginosa exposed to MOX. The findings provide valuable information on the mechanisms involved in cyanobacteria responses to antibiotic stress, and offer a theoretical basis for accurately assessing antibiotic toxicity in eutrophic aqueous environments.

Multiomics analysis reveals a substantial decrease in nanoplastics uptake and associated impacts by nano zinc oxide in fragrant rice (Oryza sativa L.)

Nanoplastics (NPs) have emerged as global environmental pollutants with concerning implications for sustainable agriculture. Understanding the underlying mechanisms of NPs toxicity and devising strategies to mitigate their impact is crucial for crop growth and development. Here, we investigated the nanoparticles of zinc oxide (nZnO) to mitigate the adverse effects of 80 nm NPs on fragrant rice. Our results showed that optimized nZnO (25 mg L-1) concentration rescued root length and structural deficits by improving oxidative stress response, antioxidant defense mechanism and balanced nutrient levels, compared to seedlings subjected only to NPs stress (50 mg L-1). Consequently, microscopy observations, Zeta potential and Fourier transform infrared (FTIR) results revealed that NPs were mainly accumulated on the initiation joints of secondary roots and between cortical cells that blocks the nutrients uptake, while the supplementation of nZnO led to the formation of aggregates with NPs, which effectively impedes the uptake of NPs by the roots of fragrant rice. Transcriptomic analysis identified a total of 3973, 3513 and 3380 differentially expressed genes (DEGs) in response to NPs, nZnO and NPs+nZnO, respectively, compared to the control. Moreover, DEGs were significantly enriched in multiple pathways including biosynthesis of secondary metabolite, phenylpropanoid biosynthesis, amino sugar and nucleotide sugar metabolism, carotenoid biosynthesis, plant-pathogen interactions, MAPK signaling pathway, starch and sucrose metabolism, and plant hormone signal transduction. These pathways could play a significant role in alleviating NPs toxicity and restoring fragrant rice roots. Furthermore, metabolomic analysis demonstrated that nZnO application restored 2-acetyl-1-pyrroline (2-AP) pathways genes expression, enzymatic activities, and the content of essential precursors related to 2-AP biosynthesis under NPs toxicity, which ultimately led to the restoration of 2-AP content in the leaves. In conclusion, this study shows that optimized nZnO application effectively alleviates NPs toxic effects and restores both root structure and aroma production in fragrant rice leaves. This research offers a sustainable and practical strategy to enhance crop production under NPs toxicity while emphasizing the pivotal role of essential micronutrient nanomaterials in agriculture.

Effect of microplastics used in agronomic practices on agricultural soil properties and plant functions: Potential contribution to the circular economy of rural areas

The extensive use of plastic materials and their improper disposal results in high amounts of plastic waste in the environment. Aging of plastics leads to their breakdown into smaller particles, such as microplastics (MPs) and nanoplastics. This research investigates plastics used in agricultural practices as they contribute to MP pollution in agricultural soils. The distribution and characteristics of MPs in agricultural soils were evaluated. In addition, the effect of MPs on soil properties, the relationship between MPs and metals in soil, the effect of MPs on the fate of pesticides in agricultural soils and the influence of MPs on plant growth were analysed, discussing legume, cereal and vegetable crops. Finally, a brief description of the main methods of chemical analysis and identification of MPs is presented. This study will contribute to a better understanding of MPs in agricultural soils and their effect on the soil-plant system. The changes induced by MPs in soil parameters can lead to potential benefits as it is possible to increase the availability of micronutrients and reduce plant uptake of toxic elements. Furthermore, although plastic pollution remains an emerging threat to soil ecosystems, their presence may result in benefits to agricultural soils, highlighting the principles of the circular economy.

Fluorescent carbon dot embedded polystyrene: an alternative for micro/nanoplastic translocation study in leguminous plants

Micro/nanoplastics are widespread in terrestrial ecosystem. Even though many studies have been reported on the effects of these in marine environment, studies concerning their accumulation and impact on terrestrial ecosystem have been scanty. The current study was designed to determine how terrestrial plants, especially legumes, interact with micro/nanoplastics to gain insights into their uptake and translocation. The paper describes the synthesis of fluorescent carbon dot embedded polystyrene (CDPS) followed by its characterization. Translocation studies at different concentrations from 2 to 100% (v/v) for tracking the movement and accumulation of microplastics in Vigna radiata and Vigna angularis were performed. The optical properties of the synthesized CDPS were investigated, and their translocation within the plants was visualized using fluorescence microscopy. These findings were further validated by scanning electron microscopy (SEM) imaging of the plant sections. The results showed that concentrations higher than 6% (v/v) displayed noticeable fluorescence in the vascular region and on the cell walls, while concentrations below this threshold did not. The study highlights the potential of utilizing fluorescent CDPS as markers for investigating the ecological consequences and biological absorption of microplastics in agricultural systems. This method offers a unique technique for monitoring and analyzing the routes of microplastic accumulation in edible plants, with significant implications for both food safety and environmental health.

Unveiling the impact of microplastics and nanoplastics on vascular plants: A cellular metabolomic and transcriptomic review

With increasing plastic manufacture and consumption, microplastics/nanoplastics (MP/NP) pollution has become one of the world's pressing global environmental issues, which poses significant threats to ecosystems and human health. In recent years, sharp increasing researches have confirmed that MP/NP had direct or indirect effects on vegetative growth and sexual process of vascular plant. But the potential mechanisms remain ambiguous. MP/NP particles can be adsorbed and/or absorbed by plant roots or leaves and thus cause diverse effects on plant. This holistic review aims to discuss the direct effects of MP/NP on vascular plant, with special emphasis on the changes of metabolic and molecular levels. MP/NP can alter substance and energy metabolism, as well as shifts in gene expression patterns. Key aspects affected by MP/NP stress include carbon and nitrogen metabolism, amino acids biosynthesis and plant hormone signal transduction, expression of stress related genes, carbon and nitrogen metabolism related genes, as well as those involved in pathogen defense. Additionally, the review provides updated insights into the growth and physiological responses of plants exposed to MP/NP, encompassing phenomena such as seed/spore germination, photosynthesis, oxidative stress, cytotoxicity, and genotoxicity. By examining the direct impact of MP/NP from both physiological and molecular perspectives, this review sets the stage for future investigations into the complex interactions between plants and plastic pollutants.

A metabolomics perspective on the effect of environmental micro and nanoplastics on living organisms: A review

The increasing trend regarding the use of plastics has arisen an exponential concern on the fate of their derived products to the environment. Among these derivatives, microplastics and nanoplastics (MNPs) have been featured for their associated environmental impact due to their low molecular size and high surface area, which has prompted their ubiquitous transference among all environmental interfaces. Due to the heterogenous chemical composition of MNPs, the study of these particles has focused a high number of studies, as a result of the myriad of associated physicochemical properties that contribute to the co-transference of a wide range of contaminants, thus becoming a major challenge for the scientific community. In this sense, both primary and secondary MNPs are well-known to be adscribed to industrial and urbanized areas, from which they are massively released to the environment through a multiscale level, involving the atmosphere, hydrosphere, and lithosphere. Consequently, much research has been conducted on the understanding of the interconnection between those interfaces, that motivate the spread of these contaminants to biological systems, being mostly represented by the biosphere, especially phytosphere and, finally, the anthroposphere. These findings have highlighted the potential hazardous risk for human health through different mechanisms from the environment, requiring a much deeper approach to define the real risk of MNPs exposure. As a result, there is a gap of knowledge regarding the environmental impact of MNPs from a high-throughput perspective. In this review, a metabolomics-based overview on the impact of MNPs to all environmental interfaces was proposed, considering this technology a highly valuable tool to decipher the real impact of MNPs on biological systems, thus opening a novel perspective on the study of these contaminants.

Comparative analysis of the effects of microplastics and nitrogen on maize and wheat: Growth, redox homeostasis, photosynthesis, and AsA-GSH cycle

Microplastics (MPs) pose a significant threat to the function of agro-ecosystems. At present, research on MPs has mainly focused on the effects of different concentrations or types of MPs on a crop, while ignoring other environmental factors. In agricultural production, the application of nitrogen (N) fertilizer is an important means to maintain the high yield of crops. The effects of MPs and N on growth parameters, photosynthetic system, active oxygen metabolism, nutrient content, and ascorbate-glutathione (AsA-GSH) cycle of maize and wheat were studied in order to explicit whether N addition could effectively alleviate the effects of MPs on maize and wheat. The results showed that MPs inhibited the plant height of both maize and wheat, and MPs effects on physiological traits of maize were more severe than those of wheat, reflecting in reactive oxygen metabolism and restriction of photosynthetic capacity. Under the condition of N supply, AsA-GSH cycle of two plants has different response strategies to MPs: Maize promoted enzyme activity and co-accumulation of AsA and GSH, while wheat tended to consume AsA and accumulate GSH. N application induced slight oxidative stress on maize, which was manifested as an increase in hydrogen peroxide and malonaldehyde contents, and activities of polyphenol oxidase and peroxidase. The antioxidant capacity of maize treated with the combination of MPs + N was better than that treated with N or MPs alone. N could effectively alleviate the adverse effects of MPs on wheat by improving the antioxidant capacity.

Microplastics increase cadmium absorption and impair nutrient uptake and growth in red amaranth (Amaranthus tricolor L.) in the presence of cadmium and biochar

Microplastic (MP) pollution in terrestrial ecosystems is gaining attention, but there is limited research on its effects on leafy vegetables when combined with heavy metals. This study examines the impact of three MP types-polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS)-at concentrations of 0.02, 0.05, and 0.1% w/w, along with cadmium (Cd) and biochar (B), on germination, growth, nutrient absorption, and heavy metal uptake in red amaranth (Amaranthus tricolor L.). We found that different MP types and concentrations did not negatively affect germination parameters like germination rate, relative germination rate, germination vigor, relative germination vigor, and germination speed. However, they increased phytotoxicity and decreased stress tolerance compared to an untreated control (CK1). The presence of MPs, particularly the PS type, reduced phosphorus and potassium uptake while enhancing Cd uptake. For example, treatments PS0.02CdB, PS0.05CdB, and PS0.1CdB increased Cd content in A. tricolor seedlings by 158%, 126%, and 44%, respectively, compared to the treatment CdB (CK2). Additionally, MP contamination led to reduced plant height, leaf dry matter content, and fresh and dry weights, indicating adverse effects on plant growth. Moreover, the presence of MPs increased bioconcentration factors and translocation factors for Cd, suggesting that MPs might act as carriers for heavy metal absorption in plants. On the positive side, the addition of biochar improved several root parameters, including root length, volume, surface area, and the number of root tips in the presence of MPs, indicating potential benefits for plant growth. Our study shows that the combination of MPs and Cd reduces plant growth and increases the risk of heavy metal contamination in food crops. Further research is needed to understand how different MP types and concentrations affect various plant species, which will aid in developing targeted mitigation strategies and in exploring the mechanisms through which MPs impact plant growth and heavy metal uptake. Finally, investigating the potential of biochar application in conjunction with other amendments in mitigating these effects could be key to addressing MP and heavy metal contamination in agricultural systems.

Polystyrene nanoplastics distinctly impact cadmium uptake and toxicity in Arabidopsis thaliana

The ubiquitous presence of micro- and nanoplastics (MNPs) in soil has raised concerns regarding their potential effects on terrestrial plants. The coexistence and interactions between MNPs and heavy metals altering their phytotoxicity deserves further investigation. In this study, we explored the impacts of various concentrations of polystyrene nanoplastics (PS-NPs) and cadmium (Cd) alone or in combination on the growth and development of Arabidopsis thaliana. Additionally, we examined the effects of combined stress on the uptake and translocation of Cd within Arabidopsis thaliana. Our findings revealed several key insights: PS-NPs exhibited the capability to internalize in the maturation zone of Arabidopsis roots; the presence of Cd changed the particle size and zeta potential of PS-NPs; the presence of PS-NPs heightened Cd accumulation in the underground parts of Arabidopsis seedlings, leading to a stronger oxidative stress response in these regions; the composite stress exerted a more pronounced effect on the growth and development of Arabidopsis compared to individual stresses. Interestingly, while higher PS-NPs concentrations hindered Cd migration from roots to leaves, they also acted as carriers for Cd uptake in Arabidopsis roots. These findings shed light on the combined impacts of MNPs and heavy metals on plant physiology, offering theoretical insights to guide risk assessment strategies for MNPs and heavy metals in terrestrial ecosystems.

Regulatory potential of secondary metabolite DIMBOA and baicalein to imazethapyr-induced toxicity in wheat seedlings

Controlling and mitigating the toxicity of herbicides to non-target plants is of significant importance in reducing ecological risks. The development of green and natural herbicide control technologies has become an urgent necessity. In this paper, how 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazine-3(4H)-one (DIMBOA) and baicalein alleviated oxidative stress induced by imazethapyr (IM) in wheat seedlings was investigated. We found that DIMBOA and baicalein enhanced the antioxidant enzyme activities in wheat seedlings exposed to IM and reduced the excessive reactive oxygen species due to IM stress by 21.3% and 23.5%, respectively. DIMBOA and baicalein also restored the iron content reduced by IM and effectively mitigated Fe2+ overload by alleviating the response of heme oxygenase 1 to IM stress. The antioxidant and iron homeostatic maintenance properties of DIMBOA and baicalein enhanced the defenses of wheat seedlings against IM stress. Our results highlight the potential implication of secondary metabolites as natural products to modulate herbicide toxicity to non-target plants.

Mechanistic insight into the impact of polystyrene microparticle on submerged plant during asexual propagules germination to seedling: Internalization in functional organs and alterations of physiological phenotypes

Asexual reproduction is one of the most important propagations in aquatic plants. However, there is a lack of information about the growth-limiting mechanisms induced by microplastics on the submerged plant during asexual propagule germination to seedling. Hence, we investigated the effects of two sizes (2 µm, 0.2 µm) and three concentrations (0.5 mg/L, 5 mg/L, and 50 mg/L) of polystyrene microplastics (PSMPs) on Potamogeton crispus turion germination and seedling growth. Both PSMPs sizes were found in P. crispus seedling tissues. Metabolic profile alterations were observed in leaves, particularly affecting secondary metabolic pathways and ATP-binding cassette transporters. Metal elements are indispensable cofactors for photosynthesis; however, alterations in the metabolic profile led to varying degrees of reduced concentrations in magnesium, iron, copper, and zinc within P. crispus. Therefore, the maximum quantum yield of photosystem II significantly decreased in all concentrations with 0.2 µm-PSMPs, and at 50 mg/L with 2 µm-PSMPs. These findings reveal that internalization of microplastics, nutrient absorption inhibition, and metabolic changes contribute to the negative impact on P. crispus seedlings.

Unveiling the detrimental effects of polylactic acid microplastics on rice seedlings and soil health

The environmental impact of biodegradable polylactic acid microplastics (PLA-MPs) has become a global concern, with documented effects on soil health, nutrient cycling, water retention, and crop growth. This study aimed to assess the repercussions of varying concentrations of PLA-MPs on rice, encompassing aspects such as growth, physiology, and biochemistry. Additionally, the investigation delved into the influence of PLA-MPs on soil bacterial composition and soil enzyme activities. The results illustrated that the highest levels of PLA-MPs (2.5%) impaired the photosynthesis activity of rice plants and hampered plant growth. Plants exposed to the highest concentration of PLA-MPs (2.5%) displayed a significant reduction of 51.3% and 47.7% in their root and shoot dry weights, as well as a reduction of 53% and 49% in chlorophyll a and b contents, respectively. The activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX) in rice leaves increased by 3.1, 2.8, 3.5, and 5.2 folds, respectively, with the highest level of PLA-MPs (2.5%). Soil enzyme activities, such as CAT, urease, and dehydrogenase (DHA) increased by 19.2%, 10.4%, and 22.5%, respectively, in response to the highest level of PLA-MPs (2.5%) application. In addition, PLA-MPs (2.5%) resulted in a remarkable increase in the relative abundance of soil Proteobacteria, Nitrospirae, and Firmicutes by 60%, 31%, and 98.2%, respectively. These findings highlight the potential adverse effects of PLA-MPs on crops and soils. This study provides valuable insights into soil-rice interactions, environmental risks, and biodegradable plastic regulation, underscoring the need for further research.

Plant and microbial response in constructed wetland treating tetracycline antibiotic polluted water: Evaluating the effects of microplastic size and concentration

Microplastics (MPs) and antibiotics are novel water pollutants that have attracted increasing attention. Constructed wetlands (CWs) are widely applied treating various types of polluted water. How these two new pollutants affect plants and microorganisms in CWs, especially deciphering the unknown roles of MPs size and concentration, is of great essential. Here, five CW treatments with submerged macrophyte Myriophyllum aquaticum were established to treat oxytetracycline (OTC) antibiotic-polluted water. The effects of polystyrene (PS) nanoplastics (NPs) (700 nm) and MPs (90-110 μm) on plant and microbial communities at 10 μg/L and 1 mg/L, respectively, were systematically evaluated. PS reduced the nitrogen and phosphorus removal efficiencies and inhibited OTC removal. Low doses (10 μg/L) of NPs and high doses (1 mg/L) of MPs had the greatest effects on plant and microbial responses. The overall effect of MPs was greater than that of NPs. Compared with high NPs concentration (1 mg/L), low concentrations (10 μg/L) had higher catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) content. However, the activity and content of MPs at low concentrations (10 μg/L) were lower than those at high concentrations (1 mg/L). The coexistence of OTC and MPs/NPs decreased the microbial diversity and abundance. Low doses of NPs and high doses of MPs decreased the relative abundance of Abditibacteriota, Deinococccota, and Zixibacteria. Redundancy and network analyses revealed a strong correlation between pollutant removal and plant and microbial responses. NH4+-N and OTC removal was positively and negatively correlated with CAT, SOD, and MDA content, respectively. MDA positively correlated to chlorophyll content, whereas SOD showed a negative correlation with Chloroflexi. This study highlighted the scale effect of MPs in wastewater treatment via CWs. It enhances our understanding of the response of plants and microorganisms to the remediation of water co-polluted with MPs and antibiotics.

Uptake and effect of carboxyl-modified polystyrene microplastics on cotton plants

Microplastics (MPs) have emerged as a significant global environmental concern, particularly within agricultural soil systems. The extensive use of plastic film mulching in cotton cultivation has led to the alarming presence of MP pollution in cotton fields. However, the uptake and effects of MPs on the growth of cotton plants are poorly understood. In this study, we conducted a comprehensive analysis of hydroponically cultured cotton seedlings at the phenotypic, transcriptional, and metabolic levels after exposure to carboxyl-modified polystyrene microplastics (PS-COOH). Treatment with three concentrations of PS-COOH (100, 300, and 500 mg/L) resulted in notable growth inhibition of treated plants and exhibited a dose-dependent effect. And, PS-COOH can invade cotton roots and be absorbed through the intercellular spaces via apoplastic uptake, with accumulation commensurate with treatment duration. Transcriptomic analysis showed significant up-regulation of genes associated with antioxidant activity in response to 300 mg/L PS-COOH treatment, suggesting the induction of oxidative stress. In addition, the PS-COOH treatment activated the phenylpropanoid biosynthesis pathway, leading to lignin and flavonoid accumulation, and altered sucrose catabolism. These findings illustrate the absorption and effects of MPs on cotton seedlings and offer valuable insights into the potential toxicity of MPs to plants in soil mulched with plastic film.

Polyethylene microplastic modulates lettuce root exudates and induces oxidative damage under prolonged hydroponic exposure

Root exudates are pivotal in plant stress responses, however, the impact of microplastics (MPs) on their release and characteristics remains poorly understood. This study delves into the effects of 0.05 % and 0.1 % (w/w) additions of polyethylene (PE) MPs on the growth and physiological properties of lettuce (Lactuca sativa L.) following 28 days of exposure. The release characteristics of root exudates were assessed using UV-vis and 3D-EEM. The results indicated that PE increased leaf number but did not significantly affect other agronomic traits or pigment contents. Notably, 0.05 % PE increased the total root length and surface area compared to the 0.1 % addition, while a non-significant trend towards decreased root activity was observed with PE MPs. PE MPs with 0.1 % addition notably reduced the DOC concentration in root exudates by 37.5 %, while 0.05 % PE had no impact on DOC and DON concentrations. PE addition increased the SUVA254, SUVA260, and SUVA280 values of root exudates, with the most pronounced effect seen in the 0.05 % PE treatment. This suggests an increase of aromaticity and hydrophobic components induced by PE addition. Fluorescence Regional Integration (FRI) analysis of 3D-EEM revealed that aromatic proteins (region I and II) were dominant in root exudates, with a slight increase in fulvic acid-like substances (region III) under 0.1 % PE addition. Moreover, prolonged PE exposure induced ROS damage in lettuce leaves, evidenced by a significant increase in content and production rate of O2·-. The decrease in CAT and POD activities may account for the lettuce's response to environmental stress, potentially surpassing its tolerance threshold or undergoing adaptive regulation. These findings underscore the potential risk of prolonged exposure to PE MPs on lettuce growth.

The effects of Micro/Nano-plastics exposure on plants and their toxic mechanisms: A review from multi-omics perspectives

In recent years, plastic pollution has become a global environmental problem, posing a potential threat to agricultural ecosystems and human health, and may further exacerbate global food security problems. Studies have revealed that exposure to micro/nano-plastics (MPs/NPs) might cause various aspects of physiological toxicities, including plant biomass reduction, intracellular oxidative stress burst, photosynthesis inhibition, water and nutrient absorption reduction, cellular and genotoxicity, seed germination retardation, and that the effects were closely related to MP/NP properties (type, particle size, functional groups), exposure concentration, exposure duration and plant characteristics (species, tissue, growth stage). Based on a brief review of the physiological toxicity of MPs/NPs to plant growth, this paper comprehensively reviews the potential molecular mechanism of MPs/NPs on plant growth from perspectives of multi-omics, including transcriptome, metabolome, proteome and microbiome, thus to reveal the role of MPs/NPs in plant transcriptional regulation, metabolic pathway reprogramming, protein translational and post-translational modification, as well as rhizosphere microbial remodeling at multiple levels. Meanwhile, this paper also provides prospects for future research, and clarifies the future research directions and the technologies adopted.

Microplastics alter the equilibrium of plant-soil-microbial system: A meta-analysis

Microplastics (MPs) are widely identified as emerging hazards causing considerable eco-toxicity in terrestrial ecosystems, but the impacts differ in different ecosystem functions among different chemical compositions, morphology, sizes, concentrations, and experiment duration. Given the close relationships and trade-offs between plant and soil systems, probing the "whole ecosystem" instead of individual functions must yield novel insights into MPs affecting terrestrial ecosystems. Here, a comprehensive meta-analysis was employed to reveal an unambiguous response of the plant-soil-microbial system to MPs. Results showed that in view of plant, soil, and microbial functions, the general response patterns of plant and soil functions to MPs were obviously opposite. For example, polyethylene (PE) and polyvinyl chloride (PVC) MPs highly increased plant functions, while posed negative effects on soil functions. Polystyrene (PS) and biodegradable (Bio) MPs decreased plant functions, while stimulating soil functions. Additionally, low-density polyethylene (LDPE), PE, PS, PVC, Bio, and granular MPs significantly decreased soil microbial functions. These results clearly revealed that MPs alter the equilibrium of the plant-soil-microbial system. More importantly, our results further revealed that MPs tended to increase ecosystem multifunctionality, e.g., LDPE and PVC MPs posed positive effects on ecosystem multifunctionality, PE, PS, and Bio MPs showed neutral effects on ecosystem multifunctionality. Linear regression analysis showed that under low MPs size (<100 µm), ecosystem multifunctionality was gradually reduced with the increased size of MPs. The response of ecosystem multifunctionality showed a concave shape pattern along the gradient of experimental duration which was lower than 70 days. More importantly, there was a threshold (i.e., 5% w/w) for the effects of MPs concentration on ecosystem multifunctionality, i.e., under low concentration (< 5% w/w), ecosystem multifunctionality was gradually increased with the increased concentration of MPs, while ecosystem multifunctionality was gradually decreased under high concentration (i.e., > 5% w/w). These findings emphasize the importance of studying the effects of MPs on plant-soil-microbial systems and help us identify ways to reduce the eco-toxicity of MPs and maintain environmental safety in view of an ecology perspective.

Occurrence, transport, and toxicity of microplastics in tropical food chains: perspectives view and way forward

Microplastics, which have a diameter of less than 5 mm, are becoming an increasingly prevalent contaminant in terrestrial and aquatic ecosystems due to the dramatic increase in plastic production to 390.7 million tonnes in 2021. Among all the plastics produced since 1950, nearly 80% ended up in the environment or landfills and eventually reached the oceans. Currently, 82-358 trillion plastic particles, equivalent to 1.1-4.9 million tonnes by weight, are floating on the ocean's surface. The interactions between microorganisms and microplastics have led to the transportation of other associated pollutants to higher trophic levels of the food chain, where microplastics eventually reach plants, animals, and top predators. This review paper focuses on the interactions and origins of microplastics in diverse environmental compartments that involve terrestrial and aquatic food chains. The present review study also critically discusses the toxicity potential of microplastics in the food chain. This systematic review critically identified 206 publications from 2010 to 2022, specifically reported on microplastic transport and ecotoxicological impact in aquatic and terrestrial food chains. Based on the ScienceDirect database, the total number of studies with "microplastic" as the keyword in their title increased from 75 to 4813 between 2010 and 2022. Furthermore, various contaminants are discussed, including how microplastics act as a vector to reach organisms after ingestion. This review paper would provide useful perspectives in comprehending the possible effects of microplastics and associated contaminants from primary producers to the highest trophic level (i.e. human health).

Harnessing microbial interactions with rice: Strategies for abiotic stress alleviation in the face of environmental challenges and climate change

Rice, which feeds more than half of the world's population, confronts significant challenges due to environmental and climatic changes. Abiotic stressors such as extreme temperatures, drought, heavy metals, organic pollutants, and salinity disrupt its cellular balance, impair photosynthetic efficiency, and degrade grain quality. Beneficial microorganisms from rice and soil microbiomes have emerged as crucial in enhancing rice's tolerance to these stresses. This review delves into the multifaceted impacts of these abiotic stressors on rice growth, exploring the origins of the interacting microorganisms and the intricate dynamics between rice-associated and soil microbiomes. We highlight their synergistic roles in mitigating rice's abiotic stresses and outline rice's strategies for recruiting these microorganisms under various environmental conditions, including the development of techniques to maximize their benefits. Through an in-depth analysis, we shed light on the multifarious mechanisms through which microorganisms fortify rice resilience, such as modulation of antioxidant enzymes, enhanced nutrient uptake, plant hormone adjustments, exopolysaccharide secretion, and strategic gene expression regulation, emphasizing the objective of leveraging microorganisms to boost rice's stress tolerance. The review also recognizes the growing prominence of microbial inoculants in modern rice cultivation for their eco-friendliness and sustainability. We discuss ongoing efforts to optimize these inoculants, providing insights into the rigorous processes involved in their formulation and strategic deployment. In conclusion, this review emphasizes the importance of microbial interventions in bolstering rice agriculture and ensuring its resilience in the face of rising environmental challenges.