Effects of microplastics on lentil (Lens culinaris) seed germination and seedling growth

The varied effects of different microplastics on stem development and carbon-nitrogen metabolism in tomato

Microplastics (MPs) pollution negatively impacts agricultural production, posing serious challenges to food security. However, research on the effects of different MPs types on plant growth, particularly on anatomical structures and carbon-nitrogen metabolism, is limited. This study investigates the effects of six MPs types on tomato (Solanum lycopersicum cv. Micro Tom) seedlings, including four non-degradable plastics (polyethylene [PE], polypropylene [PP], polystyrene [PS], and polyvinyl chloride [PVC]) and two biodegradable plastics (polybutylene succinate [PBS] and polylactic acid [PLA]). Results showed that MPs exposure inhibited seedling growth, with the degree of inhibition dependent on both the concentration and MPs type. MPs exert a significant negative impact on the development of the cortex (ct), vascular bundles (VBs), and pith tissues (pi) in tomato stems. Among them, PS-MPs induce relatively weaker negative effects. Analyses of key enzyme activities and gene expression revealed that MPs inhibited glycolysis pathway (EMP) and the tricarboxylic acid cycle (TCA), while enhancing the pentose phosphate pathway (PPP). Specifically, PBS-MPs and PVC-MPs strongly suppressed carbon assimilation, while PBS-MPs severely inhibited nitrogen assimilation. The results indicate that the negative impacts of biodegradable plastics on plants are comparable to those of traditional plastics. This study improves our understanding of the specific toxic effects of various MPs types on plant growth and metabolism.

Dynamics and Impacts of Microplastics (MPs) and Nanoplastics (NPs) on Ecosystems and Biogeochemical Processes: The Need for Robust Regulatory Frameworks

Microplastics (MPs) and nanoplastics (NPs) pose significant threats to aquatic and terrestrial ecosystems, disrupting nutrient cycling, altering soil properties, and affecting microbial communities. MPs and NPs bioaccumulate and contribute to global nutrient and water cycle disruptions, intensifying the impact of climate change. Despite the widespread use of plastics, inadequate plastic waste management leads to persistent environmental pollution. Toxic compounds are transported by MPs and NPs, affecting food chains, nutrient cycles, and overall ecosystem health. MPs impact soil biogeochemistry, microbial activity, and greenhouse gas emissions by altering the nitrogen and carbon cycles. One of the largest gaps in microplastic (MP) research today is the lack of standardized sampling and analytical methods. This lack of standardization significantly complicates the comparison of results across different studies. Multidisciplinary research and strict regulatory measures are needed to address MP pollution. This review highlights the critical need for mitigation methods to maintain ecosystem integrity and suggests standardization of sampling and data analysis. It offers insights into MP distribution, best practices for data analysis, and the impacts and interactions of MPs with biogeochemical processes. The Environmental Protection Agency has identified a critical need to improve the identification of nanoplastics. Particles smaller than 10 μm become increasingly difficult to quantify using standard MP detection practices.

Intergenerational transfer of micro(nano)plastics in different organisms

Micro(nano)plastics (MNPs), widely distributed in the environment, can be ingested and accumulated by various organisms. Recently, the transgenerational transport of MNPs from parental organisms to their offspring has attracted increasing attention. In this review, we summarize the patterns, specific pathways, and related mechanisms of intergenerational transfer of MNPs in plants, non-mammals (zooplankton and fish) and mammals. The knowledge gaps are also discussed. For plant, MNPs can accumulate in fruits and seeds by intercellular and cellular internalization pathways after uptake by roots or leaves. In zooplankton (e.g., Daphnia magna), MNPs are capable of maternal transfer via two different pathways: gut-ovary-egg and brood chamber-embryo. Intergenerational transfer of MNPs in egg-laying fish can occur through direct maternal transfer. However, MNPs may be transported through follicular pseudoplacenta, surface epithelia, and trophotaeniae pathways in ovoviviparous fish. In mammals, the maternal-fetal transport of MNPs primarily occurs through the placenta, amniotic fluid, and breastfeeding. The placental barrier is the main limitation to transfer, and the ability of MNPs to cross this barrier largely depends on the trophoblast cells via internalization and intercellular pathways. Additionally, we discuss the physicochemical properties (e.g., size, shape, and ageing) of MNPs and environmental factors (e.g., salinity, minerals, organic matter) that influence intergenerational transfer. Current challenges regarding the transfer pathways and related mechanisms, as well as future perspectives, are also addressed. This review provides valuable information for assessing the fate of MNPs in organisms and potential risks to population, community, ecosystems, and human health.

Exploring omics solutions to reduce micro/nanoplastic toxicity in plants: A comprehensive overview

The proliferation of plastic waste, particularly in the form of microplastics (MPs) and nanoplastics (NPs), has emerged as a significant environmental challenge with profound implications for agricultural ecosystems. These pervasive pollutants accumulate in soil, altering its physicochemical properties and disrupting microbial communities. MPs/NPs can infiltrate plant systems, leading to oxidative stress and cytotoxic effects, which in turn compromise essential physiological functions such as water uptake, nutrient absorption, and photosynthesis. This situation threatens crop yield and health, while also posing risks to human health and food security through potential accumulation in the food chain. Despite increasing awareness of this issue, substantial gaps still remain in our understanding of the physiological and molecular mechanisms that govern plant responses to MP/NP stress. This review employs integrative omics techniques including genomics, transcriptomics, proteomics, metabolomics, and epigenomics to elucidate these responses. High-throughput methodologies have revealed significant genetic and metabolic alterations that enable plants to mitigate the toxicity associated with MPs/NPs. The findings indicate a reconfiguration of metabolic pathways aimed at maintaining cellular homeostasis, activation of antioxidant mechanisms, and modulation of gene expression related to stress responses. Additionally, epigenetic modifications suggest that plants adapt to prolonged plastics exposure, highlighting unexplored avenues for targeted research. By integrating various omics approaches, a comprehensive understanding of molecular interactions and their effects on plant systems can be achieved. This review underscores potential targets for biotechnological and agronomic interventions aimed at enhancing plant resilience by identifying key stress-responsive genes, proteins, and metabolites. Ultimately, this work addresses critical knowledge gaps and highlights the importance of multi-omics strategies in developing sustainable solutions to mitigate the adverse effects of MP/NP pollution in agriculture, thereby ensuring the integrity of food systems and ecosystems.

Effects of polyethylene microplastics on seed germination, growth performance, biomass production and physiological function of cowpea (Vigna unguiculata) young seedlings

Microplastics (MPs) in terrestrial ecosystems have recently raised concerns; here, we performed a pot experiment and investigated the growth and development by different doses of polyethylene microplastics (PE MPs) in a net house under natural conditions and tested the effects of PE MPs on seed germination, growth performance, physiological function and biomass production of cowpea (Vigna unguiculata) for 25 days. According to the hypothesis, a significant dose-dependent inhibition of cowpea seedling's growth and development was observed depicting the phytotoxicity of PE MPs. Results indicate that high concentrations of PE MPs have antagonistic effects on the growth of plant such as plant height, leaf length and root length within a short period of time. Plants grown in PE MPs show less nutritional characters and exhibit a significant drop in leghemoglobin content as the concentration of MP increases which is one of the novel findings. The results showed a significantly increased antioxidant enzyme activity indicating the stress condition of plants due to exposure to PE MPs. PE MPs undergo initial stage of partial disintegration when it contacts with soil which were detected through SEM analysis when compared to control. Comprehensive field study involving MPs at different concentrations throughout the cowpea's whole life cycle until harvest is needed to better clarify the effects of PE MPs and produce reliable results.

Degradation Characteristics of Reed-Based PBAT Mulch and Their Effects on Plant Growth and Soil Properties

Poly (butylene adipate-co-terephthalate) (PBAT) and PBAT/reed fiber (RF) mulch films were prepared. The molecular structural changes and surface morphological evolution during the degradation process were systematically characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The prepared PBAT/RF mulch film biodegradation rate reached 90.43% within 91 days under controlled composting conditions, which was 9.52% higher than a pure PBAT mulch film. The effects of adding PBAT and PBAT/RF microplastics on soil properties and soybean physiological indicators were dynamic. The study demonstrated that the incorporation of 5% PBAT/RF mulch film fragments into soil led to a 5.1% reduction in soil pH and a 17.2% increase in soluble organic carbon content. While the effects of 5% PBAT/RF on soil urease and neutral phosphatase activities were non-significant, sucrase activity decreased by 7.4% and catalase activity was reduced to 0.38 U/g. Additionally, the addition of 5% PBAT/RF resulted in a soybean germination rate of 93.74%, which was 4.0% higher than that observed in the group treated with 5% PBAT alone. The experimental data revealed a 7.2% reduction in leaf chlorophyll content, with concomitant growth inhibition in the soybean seedlings. The study demonstrated that the PBAT/RF composite film achieved 89% biodegradation within 180 days under field conditions, effectively mitigating post-application effects on agroecosystems compared to conventional polyethylene mulch.

Seed priming with alpha-tocopherol alleviates microplastic stress in Brassica rapa through modulations in morphological, physiological and biochemical attributes

Microplastics (MPs) have been regarded as emerging pollutants globally, and understanding of the injurious impacts of MPs on food crops is still scarce. MPs toxicity can disrupt the growth and physic-chemical characteristics of turnip seedlings. Hence, sustainable remediation techniques by employing growth regulators can alleviate harmful impacts and confer MPs tolerance in vegetables. It was aimed to explore the impact of α-tocopherol for the alleviation of MPs toxicity in Brassica rapa seedlings. During present investigation, seed priming was executed with 25, 50 and 100 mg L-1α-tocopherol and then concerned soaked seeds of B. rapa were grown in Perti dishes treated with MPs (50 mg L-1). The current study showed that MPs toxicity significantly reduced seed germination, growth attributes, and photosynthetic activity while remarkably boosting the level of enzymatic and non-enzymatic antioxidants. Nevertheless, seed priming with α-tocopherol mitigated the MPs stress in Brassica rapa by augmenting growth attributes, photosynthetic machinery, phenol, flavonoid, proline and antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). Furthermore, α-tocopherol supply meaningfully lowered the malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents of B. rapa under MPs stressed conditions. Hence, seed priming with α-tocopherol can be a promising strategy for promoting turnip crop production in MPs-contaminated environments. These outcomes will offer new insights into the sustainable management of the harmful effects of MPs on food crops.

Microplastic accumulation and oxidative stress in sweet pepper (Capsicum annuum Linn.): Role of the size effect

Microplastics (MPs), which are widely dispersed in terrestrial environments, threaten crop growth and human food security. However, plant accumulation and phytotoxicity related to the size effects of MPs remain insufficiently explored. This study investigated the accumulation and toxicity of two sizes of MPs on Capsicum annuum Linn. (C. annuum) through fluorescence tracing and antioxidant defense system assessment. The results revealed that the size of MPs significantly impacts their accumulation characteristics in C. annuum roots, leading to variations in toxic mechanisms, including oxidative stress and damage. Smaller MPs and higher exposure concentrations result in more pronounced growth inhibition. C. annuum roots have a critical size threshold for the absorption of MPs of approximately 1.2 μm. MPs that enter the root tissue exhibit an aggregated form, with smaller-sized MPs displaying a greater degree of aggregation. MP exposure induces oxidative stress in root tissues, with high concentrations of smaller MPs causing lipid peroxidation. Analysis of the IBR values revealed that C. annuum roots utilize ascorbic acid (ASA) to prevent oxidative damage caused by larger MPs. Conversely, smaller MPs primarily induce superoxide dismutase (SOD) and glutathione (GSH). These results emphasize the significant impact of MP size on plant antioxidant defense response mechanisms, laying the foundation for further investigating the implications for human health.

Integrating automated machine learning and metabolic reprogramming for the identification of microplastic in soil: A case study on soybean

The accumulation of polyethylene microplastic (PE-MPs) in soil can significantly impact plant quality and yield, as well as affect human health and food chain cycles. Therefore, developing rapid and effective detection methods is crucial. In this study, traditional machine learning (ML) and H2O automated machine learning (H2O AutoML) were utilized to offer a powerful framework for detecting PE-MPs (0.1 %, 1 %, and 2 % by dry soil weight) and the co-contamination of PE-MPs and fomesafen (a common herbicide) in soil. The development of the framework was based on the results of the metabolic reprogramming of soybean plants. Our study stated that traditional ML exhibits lower accuracy due to the challenges associated with optimizing complex parameters. H2O AutoML can accurately distinguish between clean soil and contaminated soil. Notably, H2O AutoML can detect PE-MPs as low as 0.1 % (with 100 % accuracy) and co-contamination of PE-MPs and fomesafen (with 90 % accuracy) in soil. The VIP and SHAP analyses of the H2O AutoML showed that PE-MPs and the co-contamination of PE-MPs and fomesafen significantly interfered with the antioxidant system and energy regulation of soybean. We hope this study can provide a reliable scientific basis for sustainable development of the environment.

The bioaccumulation and ecotoxicity of co-exposure of per(poly)fluoroalkyl substances and polystyrene microplastics to Eichhornia crassipes

Gen X and F-53B have been popularized as alternatives to PFOA and PFOS, respectively. These per(poly)fluoroalkyl substances pervasively coexist with microplastics (MPs) in aquatic environments. However, there are knowledge gaps regarding their potential eco-environmental risks. In this study, a typical free-floating macrophyte, Eichhornia crassipes (E. crassipes), was selected for hydroponic simulation of a single exposure to PFOA, PFOS, Gen X, and F-53B, and co-exposure with polystyrene (PS) microspheres. F-53B exhibited the highest bioaccumulation followed by Gen X, PFOA, and PFOS. In the presence of PS MPs, the bioavailabilities of the four PFASs shifted and the whole plant bioconcentration factors improved. All four PFASs induced severe lipid peroxidation, which was exacerbated by PS MPs. The highest integrated biomarker response (IBR) was observed for E. crassipes (IBR of shoot: 30.01, IBR of root: 22.79, and IBR of whole plant: 34.96) co-exposed to PS MPs and F-53B. The effect addition index (EAI) model revealed that PS MPs showed antagonistic toxicity with PFOA and PFOS (EAI < 0) and synergistic toxicity with Gen X and F-53B (EAI > 0). These results are helpful to compare the eco-environmental impacts of legacy and alternative PFASs for renewal process of PFAS consumption and provide toxicological, botanical, and ecoengineering insights under co-contamination with MPs.

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.

Nitrogen supply neutralizes the nanoplastic-plant interaction in a coastal wetland

The presence of nanoplastics posed a potential threat to coastal saline-alkaline wetlands where nitrogen (N) fertilizer is being implemented as an important ecological restoration measure. Notwithstanding, the effects of N inputs on plant community in polypropylene-nanoplastics (PP-NPs) coexistence environments are largely unknown. To address this, we investigated the effects of PP-NPs addition alone or combined N supply on community aboveground biomass, morphological traits, diversity, composition, niche differentiation, interspecific interactions, and assembly. Our results showed that the PP-NPs addition alone reduced community aboveground biomass and morphological traits. However, the addition of high concentration (0.5%) PP-NPs alone favored community α-diversity and reduced community stability, which could be weakened through combined N supply. Overall, the effect of PP-NPs addition alone on plant community composition was greater than that of combined N supply. We also demonstrated PP-NPs addition alone and combined N supply reduced the niche breadth of the plant community and affected the niche overlap of dominant species. In the assembly of plant communities, stochastic processes played a dominant role. We conclude that N fertilization can amend the terrestrial nanoplastics pollution, thus mitigating the effects of PP-NPs on the plant community.

A Study on the Growth and Physiological Toxicity Effects of the Combined Exposure of Microplastics and Cadmium on the Vicia faba L. Seedlings

To investigate the toxicological effects of polystyrene microplastics (PS-MPs), cadmium (Cd), and their combined contamination on the growth and physiological responses of V. faba seedlings, this experiment employed a hydroponic method. The Hoagland nutrient solution served as the control, changes in root growth, physiological and biochemical indicators of V. faba seedlings under different concentrations of PS-MPs (10, 100 mg/L) alone and combined with 0.5 mg/L Cd. The results demonstrated that the root biomass, root vitality, generation rate of superoxide radicals (O2·-), malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity increased with increasing concentration under the influence of PS-MPs alone, while the soluble sugar content and peroxidase (POD) activity decreased. In the combined treatment with Cd, the trends of these indicators are generally similar to the PS-MPs alone treatment group. However, root vitality and SOD activity showed an inverse relationship with the concentration of PS-MPs. Furthermore, laser confocal and electron microscopy scanning revealed that the green fluorescent polystyrene microspheres entered the root tips of the V. faba and underwent agglomeration in the treatment group with a low concentration of PS-MPs alone and a high concentration of composite PS-MPs with Cd.

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.

Micro/nanoplastics: Critical review of their impacts on plants, interactions with other contaminants (antibiotics, heavy metals, and polycyclic aromatic hydrocarbons), and management strategies

Microplastic/nanoplastics (MPs/NPs) contamination is not only emerging threat to the agricultural system but also constitute global hazard to the environment worldwide. Recent review articles have addressed the environmental distribution of MPs/NPs and their single-exposure phytotoxicity in various plant species. However, the mechanisms of MPs/NPs-induced phytotoxicity in conjunction with that of other contaminants remain unknown, and there is a need for strategies to ameliorate such phytotoxicity. To address this, we comprehensively review the sources of MPs/NPs, their uptake by and effects on various plant species, and their phytotoxicity in conjunction with antibiotics, heavy metals, polycyclic aromatic hydrocarbons (PAHs), and other toxicants. We examine mechanisms to ameliorate MP/NP-induced phytotoxicity, including the use of phytohormones, biochar, and other plant-growth regulators. We discuss the effects of MPs/NPs -induced phytotoxicity in terms of its ability to inhibit plant growth and photosynthesis, disrupt nutrient metabolism, inhibit seed germination, promote oxidative stress, alter the antioxidant defense system, and induce genotoxicity. This review summarizes the novel strategies for mitigating MPs/NPs phytotoxicity, presents recent advances, and highlights research gaps, providing a foundation for future studies aimed at overcoming the emerging problem of MPs/NPs phytotoxicity in edible crops.

Discrepancy of Growth Toxicity of Polystyrene Nanoplastics on Soybean (Glycine max) and Mung Bean (Vigna radiata)

Nanoplastics, as a hot topic of novel contaminants, lack extensive concern in higher plants; especially the potential impact and mechanism of nanoplastics on legume crops remains elusive. In this study, the toxicity of polystyrene nanoplastics (PS-NPs, 200 nm) with diverse doses (control, 10, 50, 100, 200, 500 mg/L) to soybean and mung bean plants grown hydroponically for 7 d was investigated at both the macroscopic and molecular levels. The results demonstrated that the root length of both plants was markedly suppressed to varying degrees. Similarly, mineral elements (Fe, Zn) were notably decreased in soybean roots, consistent with Cu alteration in mung bean. Moreover, PS-NPs considerably elevated malondialdehyde (MDA) levels only in soybean roots. Enzyme activity data indicated mung bean exhibited significant damage only at higher doses of PS-NPs stress than soybean, implying mung bean is more resilient. Transcriptome analysis showed that PS-NPs stimulated the expression of genes associated with the antioxidant system in plant roots. Furthermore, starch and sucrose metabolism might play a key role in coping with PS-NPs to enhance soybean resistance, but the MAPK pathway was enriched in mung bean. Our findings provide valuable perspectives for an in-depth understanding of the performance of plants growing in waters contaminated by nanoplastics.

Responses of lettuce (Lactuca sativa L.) growth and soil properties to conventional non-biodegradable and new biodegradable microplastics

Residual plastic films in soils are posing a potential threat to agricultural ecosystem. However, little is known about the impacts of microplastics (MPs) derived from biodegradable and non-biodegradable plastic films on plant-soil systems. Here, we carried out a pot experiment using soil-cultivated lettuce treated by two types of MPs, degradable poly(butylene adipate-co-terephthalate) (PBAT-MPs) and non-biodegradable polyethylene (PE-MPs). MPs resulted in different degrees of reduction in shoot biomass, chlorophyll content, photosynthetic parameters, and leaf contents of nitrogen (N), phosphorus (P), and potassium (K), accelerated accumulation of hydrogen peroxide and superoxide, and increased malondialdehyde content in lettuce leaves. Moreover, MPs obviously decreased contents of total N, nitrate, ammonium, and available K in soils, and increased available P, thus altering soil nutrient availability. MPs also significantly decreased proportions of macroaggregates, and decreased soil electrical conductivity and microbial activity. PBAT-MPs had significantly greater impacts on oxidative damage, photosynthetic rate, soil aggregation, microbial activity, and soil ammonium than those of PE-MPs. Our results suggested that MPs caused oxidative damages, nutrient uptake inhibition, soil properties alteration, ultimately leading to growth reduction, and PBAT-MPs exhibited stronger impacts. Therefore, it is urgent to further study the ecological effects of MPs, especially biodegradable MPs, on soil-plant systems.

A bibliometric analysis of global research hotspots and progress on microplastics in soil‒plant systems

Plastic pollution has become a global and persistent challenge, posing threats to ecosystems and organisms. In recent years, there has been a rapid increase in scientific research focused on understanding microplastics in the soil‒plant system. This surge is primarily driven by the direct impact of microplastics on agricultural productivity and their association with human activities. In this study, we conducted a comprehensive bibliometric analysis to provide an overview of the current research on microplastics in soil‒plant systems. We systematically analysed 192 articles and observed a significant rise in research interests since 2017. Notably, China has emerged as a leading contributor in terms of published papers, closely followed by Germany and the Netherlands. Through co-authorship network analysis, we identified 634 different institutions that participated in publishing papers in this field, with the Chinese Academy of Sciences having the most collaborations. In the co-occurrence keyword network, we identified four clusters focusing on the diversity of microplastics within the agroecosystem, transportation, and quantification of microplastics in soil, analysis of plastic contamination type and impact, and investigation of microplastic phytotoxicity. Furthermore, we identified ten research priorities, categorized into the effects of microplastics in "soil" and "plant". The research hotspots were found to be the effect of microplastics on soil physicochemical properties and the synergistic phytotoxicity of microplastics with other pollutants. Overall, this bibliometric analysis holds significant value, serving as an important reference point and offering valuable suggestions for future researchers in this rapidly advancing field.

Exploring the impact of PVC and PVA microplastics on zebrafish tissue using multi-spectral imaging, Optical Coherence Tomography (OCT) and biospeckle OCT (bOCT)

Plastics are widely used in industry and households, but improper disposal has caused their accumulation in aquatic systems worldwide. As a result, mechanical and photochemical processes break down these plastics into microplastics or nano plastics, posing a severe threat to marine organisms and humans as they enter the food chain. This study investigates the effect of Polyvinyl chloride (PVC) and Polyvinyl alcohol (PVA) microplastics in zebrafish by using multi-spectral imaging (MSI), Optical Coherence Tomography (OCT), and Biospeckle OCT (bOCT). These techniques allow for long-term studies in the fish without invasive procedures in real-time. Zebrafish were exposed to Nile red labeled PVC and PVA for 21 days with 500mg/L concentration. Image acquisition and analysis were performed every five days till the end of the study. MSI images revealed deposition of microplastics in the gills region of the fish; some diffused deposition was seen throughout the body in the PVA group towards the end of the experiment. The effect of these MPs on the structure of the gills and their exact location was determined by capturing OCT images. bOCT was used to determine the average speckle contrast for all the OCT images to determine the change in biological activity within the gills region. An increase in bioscpeckle contrast was observed for the MPs treated groups compared to the control group. PVC appeared to cause a more considerable rise in activity compared to PVA. The results indicated that the MPs exert stress on the gills and increase activity within the gills, possibly due to the blockage of the gills and disruption of the water filtration process, which could be monitored non-invasively only by using bOCT. Overall, our study demonstrates the usefulness of non-invasive, robust techniques like MSI, bOCT, and biospeckle for long-term zebrafish studies and real-time analyses.

The synergy of microplastics with the heavy metal zinc has resulted in reducing the toxic effects of zinc on lentil (Lens culinaris) seed germination and seedling growth

There is growing recognition of the impact of the rising presence of microplastics (MPs) on terrestrial plant growth and, in general, the terrestrial ecosystem. Simultaneously, there is growing heavy metal accumulation in agricultural lands at an astonishing rate owing to the overwhelming use of chemical fertilizers, herbicides, and weedicides. Thus, there is a need to investigate the synergetic effect of MPs along with heavy metals on the inducing combined toxicity. This study investigates effects at smaller exposure periods of a few hours using a novel optical imaging technique, Biospeckle Coherence Tomography. Biospeckle Optical Coherence Tomography (bOCT) is a novel optical imaging technique that we successfully demonstrated earlier in visualizing the internal activity of plants. Previous studies of authors using the bOCT technique have demonstrated its potential in the independent application of polyethylene microplastic (PEMPs) as well as zinc within 6 h after their treatments. The strong inhibitory effect of 100 mg L-1, Zn, and PEMPs alone on the germination of Lens culinaris could be visualized with bOCT. The current study demonstrated that against expectation, combined effects of Zn toxicity were reduced when combined with MPs. This is suggested due to the significant reduction of Zn uptake by the seedlings through the interaction of Zn and MPs in an aqueous solution. Mass-spectrometry results also indicate a reduced intake of Zn. Our findings suggest that PEMPs could be able to reduce the over-availability of Zn, thus mitigating the Zn toxicity on lentils.

Impacts of Plastics on Plant Development: Recent Advances and Future Research Directions

Plastics have inundated the world, with microplastics (MPs) being small particles, less than 5 mm in size, originating from various sources. They pervade ecosystems such as freshwater and marine environments, soils, and the atmosphere. MPs, due to their small size and strong adsorption capacity, pose a threat to plants by inhibiting seed germination, root elongation, and nutrient absorption. The accumulation of MPs induces oxidative stress, cytotoxicity, and genotoxicity in plants, which also impacts plant development, mineral nutrition, photosynthesis, toxic accumulation, and metabolite production in plant tissues. Furthermore, roots can absorb nanoplastics (NPs), which are then distributed to stems, leaves, and fruits. As MPs and NPs harm organisms and ecosystems, they raise concerns about physical damage and toxic effects on animals, and the potential impact on human health via food webs. Understanding the environmental fate and effects of MPs is essential, along with strategies to reduce their release and mitigate consequences. However, a full understanding of the effects of different plastics, whether traditional or biodegradable, on plant development is yet to be achieved. This review offers an up-to-date overview of the latest known effects of plastics on plants.

Phytotoxicity assessment of dandelion exposed to microplastics using membership function value and integrated biological response index

Microplastic (MP) pollution is a critical environmental issue. Dandelions could be used as a biomonitor of environmental pollution. However, the ecotoxicology of MPs in dandelions remains unclear. Therefore, the toxic effects of polyethylene (PE), polystyrene (PS), and polypropylene (PP) at concentrations of 0, 10, 100, and 1000 mg L-1 on the germination and early seedling growth of dandelion were investigated. PS and PP inhibited seed germination and decreased root length and biomass while promoting membrane lipid peroxidation, increasing O2•-, H2O2, SP, and proline contents, and enhancing the activities of SOD, POD, and CAT. Principal component analysis (PCA) and membership function value (MFV) analysis indicated that PS and PP could be more harmful than PE in dandelion, especially at 1000 mg L-1. In addition, according to the integrated biological response (IBRv2) index analysis, O2•-, CAT, and proline were sensitive biomarkers of dandelion contamination by MPs. Here we provide evidence that dandelion has the potential to be a biomonitor to assess the phytotoxicity of MPs pollution, especially PS with high toxicity. Meanwhile, we believe that if dandelion is to be used as a biomonitor for MPs, attention should also be paid to the practical safety of dandelion.

Microplastic stress in plants: effects on plant growth and their remediations

Microplastic (MP) pollution is becoming a global problem due to the resilience, long-term persistence, and robustness of MPs in different ecosystems. In terrestrial ecosystems, plants are exposed to MP stress, thereby affecting overall plant growth and development. This review article has critically analyzed the effects of MP stress in plants. We found that MP stress-induced reduction in plant physical growth is accompanied by two complementary effects: (i) blockage of pores in seed coat or roots to alter water and nutrient uptake, and (ii) induction of drought due to increased soil cracking effects of MPs. Nonetheless, the reduction in physiological growth under MP stress is accompanied by four complementary effects: (i) excessive production of ROS, (ii) alteration in leaf and root ionome, (iii) impaired hormonal regulation, and (iv) decline in chlorophyll and photosynthesis. Considering that, we suggested that targeting the redox regulatory mechanisms could be beneficial in improving tolerance to MPs in plants; however, antioxidant activities are highly dependent on plant species, plant tissue, MP type, and MP dose. MP stress also indirectly reduces plant growth by altering soil productivity. However, MP-induced negative effects vary due to the presence of different surface functional groups and particle sizes. In the end, we suggested the utilization of agronomic approaches, including the application of growth regulators, biochar, and replacing plastic mulch with crop residues, crop diversification, and biological degradation, to ameliorate the effects of MP stress in plants. The efficiency of these methods is also MP-type-specific and dose-dependent.

Physiological analysis and transcriptome profiling reveals the impact of microplastic on melon (Cucumis melo L.) seed germination and seedling growth

The wide application of agricultural plastics leads to microplastic (MP) accumulation in the soil and inevitably result in MP pollution. Melon is an economically important horticultural crop that is widely cultivated with plastic film mulching. However, the impact of MP pollution on plant growth remains largely unclear. Here we reported the morphological, physiological, biochemical responses and transcriptome re-programing of melon responses to MP on seed germination and seedling growth. Polyvinyl chloride particles were added to potting mix to simulate MP exposure environment (MEE). The results showed that low and medium concentrations (1-4 g kg-1) of MEE had a significant adverse effect on seed germination and seedling growth. In both cases, the germination potential was decreased, young root forks increased, and tips decreased; and the dry weight of seedlings, the total length, surface area, forks and tips of root were also decreased. However, the root activity was increased. The concentration of MEE to give the best parameters was at 2 g kg-1. Catalase enzymatic activity and reactive oxygen species (ROS) in roots were decreased continuously with increased MEE concentrations. The peak values of peroxidase activity, O2.- content and generation rate, ROS enrichment and malondialdehyde content all reached the highest at 2 g kg-1. MEE also increased the proline content and decreased the contents of ascorbic acid, soluble sugar and soluble protein in these seedlings. Medium and high concentrations of MEE (4-8 g kg-1) also increased the chlorophyll b content. Low concentrations MEE (1-2 g kg-1) inhibited actual photochemical efficiency of photosystem II and photochemical quenching, two key chlorophyll fluorescence parameters. Transcriptome analysis showed that the differentially expressed genes caused by the MEE were mainly belonged to defense response, signal transduction, hormone metabolism, plant-pathogen interaction, and phenylpropanoid biosynthesis. The results of this study will help to understand the ecotoxicological effects of MEE on melons and provide data for ecological risk assessment of Cucurbitaceae vegetable cultivation.

Label-free optical interferometric microscopy to characterize morphodynamics in living plants

During the last century, fluorescence microscopy has played a pivotal role in a range of scientific discoveries. The success of fluorescence microscopy has prevailed despite several shortcomings like measurement time, photobleaching, temporal resolution, and specific sample preparation. To bypass these obstacles, label-free interferometric methods have been developed. Interferometry exploits the full wavefront information of laser light after interaction with biological material to yield interference patterns that contain information about structure and activity. Here, we review recent studies in interferometric imaging of plant cells and tissues, using techniques such as biospeckle imaging, optical coherence tomography, and digital holography. These methods enable quantification of cell morphology and dynamic intracellular measurements over extended periods of time. Recent investigations have showcased the potential of interferometric techniques for precise identification of seed viability and germination, plant diseases, plant growth and cell texture, intracellular activity and cytoplasmic transport. We envision that further developments of these label-free approaches, will allow for high-resolution, dynamic imaging of plants and their organelles, ranging in scales from sub-cellular to tissue and from milliseconds to hours.

Type-dependent effects of microplastics on tomato (Lycopersicon esculentum L.): Focus on root exudates and metabolic reprogramming

Much attention has been paid to the prevalence of microplastics (MPs) in terrestrial systems. MPs have been shown to affect the physio-biochemical properties of plants. Different MPs may have distinctive behaviors and diverse effects on plant growth. In the present study, the effects of polystyrene (PS), polyethylene (PE), and polypropylene (PP) MPs on physio-biochemical properties, root exudates, and metabolomics of tomato (Lycopersicon esculentum L.) under hydroponic conditions were investigated. Our results show that MPs exposure has adverse effects on tomato growth. MPs exposure had a significant type-dependent effect (p < 0.001) on photosynthetic gas parameters, chlorophyll content, and antioxidant enzyme activities. After exposure to MPs, the content of low molecular weight organic acids in tomato root exudates was significantly increased, which was considered as a strategy to alleviate the toxicity of MPs. In addition, MPs treatment significantly changed the metabolites of tomato root and leaf. Metabolic pathway analysis showed that MPs treatment had a great effect on amino acid metabolism. We also found that plants exposed to PS and PP MPs produced more significant metabolic reprogramming than those exposed to PE MPs. This study provides important implications for the mechanism studies on the toxic effect of various MPs on crops and their future risk assessment.

Three typical microplastics affect the germination and growth of amaranth (Amaranthus mangostanus L.) seedlings

Microplastics (MPs) have been a global emerging contaminant and have aroused wide public concern. Currently, it is still unknown the phytotoxicity effect of MPs on amaranth (Amaranthus mangostanus L.). This study investigated the early responses of amaranth by exposing its seeds to suspensions of polystyrene (PS), polyethylene (PE), and polypropylene (PP) MPs. We observed the effects of MPs on seed germination and growth of amaranth, especially on the oxidative damage in amaranth roots. Impacts of MPs on the germination and growth of amaranth varied with the type, concentration, and particle size of MPs. PE MPs and PP MPs inhibited the shoot extension of amaranth, while the root length under PP MPs treatment was generally shorter than that under PS MPs and PE MPs. The accumulation of H₂O₂ in amaranth roots increased with the rising of MPs concentration. Compared with the control, a little number of dead cells were found in the roots of amaranth under high MPs treatment. It is noteworthy that only under 100 mg/L PP treatment, the amaranthus seedlings root cells were disorganized, due to the reactive oxygen species (ROS) damage in the roots. These findings provide essential information to assess the phytotoxicity of MPs in agricultural products, and provide insights into the underlying mechanisms of the observed phytotoxicity.