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Xylem- and Phloem-Based Transport of CuO Nanoparticles in Maize (Zea mays L.)
Abstract
This work reports on the toxicity of CuO nanoparticles (NPs) to maize (Zea mays L.) and their transport and redistribution in the plant. CuO NPs (100 mg L(-1)) had no effect on germination, but inhibited the growth of maize seedlings; in comparison the dissolved Cu(2+) ions and CuO bulk particles had no obvious effect on maize growth. CuO NPs were present in xylem sap as examined by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS), showing that CuO NPs were transported from roots to shoots via xylem. Split-root experiments and high-resolution TEM observation further showed that CuO NPs could translocate from shoots back to roots via phloem. During this translocation, CuO NPs could be reduced from Cu (II) to Cu (I). To our knowledge, this is the first report of root-shoot-root redistribution of CuO NPs within maize. The current study provides direct evidence for the bioaccumulation and biotransformation of CuO NPs (20-40 nm) in maize, which has significant implications on the potential risk of NPs and food safety.
... Micronutrients such as zinc, copper, and iron play vital roles in enzyme and biomolecule structures and functions [19]. However, conventional fertilizers face challenges in providing these nutrients to plants as they have lower bioavailability [20,21]. Compared to conventional fertilizers, nano-fertilizers (NFs) offer numerous advantages, including variable solubility, consistent and effective performance, controlled release over time, targeted activity with optimal concentration, and reduced eco-toxicity. ...
... The results, as depicted in Figure 4, demonstrated the impact of different fertilizer treatments on survival and the age-specific fecundity of S. graminum. The highest agespecific fecundity of the aphid was observed on days 19,18,21,20,20, and 14 in the nano-Fe, nano-Zn, nano-Cu, N, Hog, and water treatments, respectively. Hog and N treatments showed the highest age-specific fecundity values, and the lowest was in thenano-Cu and nano-Fe treatments. ...
... The results, as depicted in Figure 4, demonstrated the impact of different fertilizer treatments on survival and the age-specific fecundity of S. graminum. The highest agespecific fecundity of the aphid was observed on days 19,18,21,20,20, and 14 in the nano-Fe, nano-Zn, nano-Cu, N, Hog, and water treatments, respectively. Hog and N treatments showed the highest age-specific fecundity values, and the lowest was in thenano-Cu and nano-Fe treatments. ...
The use of nanofertilizers has both advantages and concerns. One benefit is that nano-fertilizers can enhance plant resistance against insect pests, making them a valuable strategy in integrated pest management (IPM). This study focused on the effect of wheat leaves treated with nano-chelated fertilizers and nitrogen (N) fertilizer on the wheat aphid (Schizaphis graminum Rondani), a harmful pest of wheat plants that transmits dangerous viruses. The nano-Cu treatment showed the longest pre-adult longevity. Additionally, the nano-Cu treatment resulted in the lowest adult longevity, fecundity, nymphoposition day number, intrinsic rate of population growth (r), finite rate of population increase (λ), and net reproductive rate (R0) and gross reproductive rate (GRR). Also, nano-Cu treatment led to the highest amount of (T). The N treatment led to the highest levels of fecundity, nymphoposition days, r, λ, and R0. Nano-Fe and nano-Zn demonstrated fewer negative effects on S. graminum life table parameters than nano-Cu. Our results indicate that N treatment yielded numerous advantageous effects on the wheat aphid while simultaneously impeding the efficacy of the aphid control program. Conversely, nano-Cu treatment exhibited a detrimental influence on various parameters of the aphid’s life table, resulting in a reduction in the pest’s fitness. Consequently, the integration of nano-Cu should be seriously considered as a viable option in the IPM of the wheat aphid.
... The uptake of ZnO and CuO NPs may lead to the accumulation of NPs along the terrestrial food chain (Kim et al., 2023). It is shown that CuO NPs can be absorbed and translocated from roots to shoots via xylem in maize (Zea mays L.) (Wang et al., 2012). The uptake of CuO NPs was also observed in other plants with translocation factors of 0.05-0.10 in rice (Oryza sativa L.) (Peng et al., 2018) and 0.14-0.20 in bell pepper (Capsicum annum L.) (Peng et al., 2018). ...
... The damage of plasma membrane integrity in root cells after ZnO NPs treatment was observed; however, this was not observed in root cells after CuO NPs treatment (Fig. 4A-E). It is proposed that ZnO NPs entered the root cells through membrane disruption and nanoparticle uptake by endocytosis, while endocytosis played an important role in the uptake of CuO NPs into the root cells (Wang et al., 2012). Dark aggregates of ZnO The different lowercase letters indicate statistically significant differences between treatments at p < 0.05. ...
... or CuO NPs like those observed in the root cells were also seen in the shoot cells, suggesting that ZnO or CuO NPs can be transported to the shoots. The xylem-based transportation from root to shoot of metal NPs has been reported in different plants (Ahmed et al., 2021a;Wang et al., 2012;Zhao et al., 2017). The particle sizes in the spherical agglomerates seem smaller than those of pristine ZnO and CuO NPs (Figs. 1 and 4). ...
The increasing application of metal nanoparticles (NPs) via agrochemicals and sewage sludge results in non-negligible phytotoxicological risks. Herein, the potential phytotoxicity of ZnO and CuO NPs on wheat was determined using integrative chemical, physiological, and metabolomics analyses, in comparison to Zn 2+ and Cu 2+. It was found that ZnO or CuO NPs had a stronger inhibitory effect on wheat growth than Zn 2+ or Cu 2+. After exposure to ZnO or CuO NPs, wheat seedlings accumulated significantly higher levels of Zn or Cu than the corresponding Zn 2+ or Cu 2+ treatments, indicating the active uptake of NPs via wheat root. TEM analysis further confirmed the intake of NPs. Moreover, ZnO or CuO NPs exposure altered micronutrients (Fe, Mn, Cu, and Zn) accumulation in the tissues and decreased the activities of antioxidant enzymes. The metabolomics analysis identified 312, 357, 145, and 188 significantly changed metabolites (SCMs) in wheat root exposed to ZnO NPs, CuO NPs, Zn 2+ , and Cu 2+ , respectively. Most SCMs were nano-specific to ZnO (80%) and CuO NPs (58%), suggesting greater metabolic reprogramming by NPs than metal ions. Overall, nanospecific toxicity dominated the phytotoxicity of ZnO and CuO NPs, and our results provide a molecular perspective on the phytotoxicity of metal oxide NPs.
... However, these methods have drawbacks that limit the size of the particles that can be transported. When particles are introduced through the roots, they can be absorbed by the plant and transported to various parts of the plant through the xylem and phloem-which form the vascular system of plants (Wang et al., 2012). However, the sizes of particles that can be transported are limited because of the cell walls and their pores. ...
... Ma et al. (2017) reported that xylemand phloem-based transport of CeO 2 nanoparticles (25 nm in size) in cucumber plants showed Ce distribution and speciation in different plant tissues. Another study demonstrated the transport of CuO nanoparticles with a size of 20-40 nm in the xylem sap of Zea mays L (Wang et al., 2012). However, previous studies have only used particle sizes below 40 nm. ...
... One hundred and twelve glass bottles were used for 28 experimental treatments, each with four replicates. The treatments were combinations of four particle concentrations (0, 10, 100, and 1000 mg/L) and four immersion times (3, 6, 12, and 24 h) (Wang et al., 2012). Cut seedlings were immersed into the silica particle suspension only via the green part and not outside this part. ...
The introduction of exogenous particles into plants has promising applications in agriculture and biotechnology. Nanoparticles can be transported into plants through foliar application or root uptake. However, both methods have limitations in terms of the size of the particles (<40 nm) that can be transported due to the barriers of the cell wall and cuticle. In the present study, we proposed a novel method to deliver particles of up to 110 nm into plants by cutting the stem of tomato seedlings. We demonstrated for the first time, using water-insoluble silica colloids, that not only nanoparticles but also submicron particles can be transported toward the leaves when the plant stem is used as the entry point of particles. Thirty-five-day-old tomato seedlings were used as the target plants. When the cut stem seedlings were immersed in the colloidal particle suspension for up to 24 hours, significant particle accumulation was observed in the nodes and leaves. The relatively low particle concentrations (10 mg/L) allowed effective transport throughout the plants. Silica particles with average diameters of 10 nm and 110 nm were both well transported and moved through the stem. Even after the particles entered the plant, adventitious roots were formed, resulting in the formation of whole plants with roots, stems, and leaves. This method can be applied not only to tomatoes but also to other food crops for various applications in plant biotechnology.
... Phytonanotechnology has the potential to modify the plant's production systems, thus permitting efficient, controlled and stable agrochemicals release such as fertilizers, several pesticides and specific type of the biomolecules. 3 Understanding the interaction of nanoparticles at advanced level with the plant responses like localization and uptake can transfigure the production of crops with high disease resistance, efficient nutrients utilization and crop yields. 4 Nanomaterials are characterized by unique physicochemical features such as surface charge, surface area, agglomeration rate, surface coating and particle morphology. ...
... The NPs having size > 10 nm enter via stomata, and transportation is carried out via apo-symplastic routes in plant's vascular system. 3 The internalized NPs are transported through phloem tubes alongside sugar flow. Due to vascular transportation via phloem the NPs travel two-way and ultimately accumulated in varying organs such as fruiting bodies, stems, roots and young leaves because these plant parts can act out as potential sinks for cell sap. ...
... [107][108][109] Different consequences have been observed in plants due to ROS generation such as induction of damage due to oxidation, peroxidation of lipids, 110 change in ion transportation through cell membranes, 111 intracellular and extracellular harm to cell membrane. 3 Moreover, ROS generation in plants owing to the exposure to NPs also damage DNA by breaking its strands or point mutations resulting in expression of death receptor genes. 86 It results in leakage of intracellular Ca 2+ ions followed by disruption of mitochondria and certain proteins to be encoded are malfunctioned. ...
Phytonanotechnology plays a crucial part in the production of good quality and high-yield food. It can also alter the plant's production systems, hence permitting the efficient, controlled and stable release of agrochemicals such as fertilizers and pesticides. An advanced understanding of nanomaterials interaction with plant responses like localization and uptake, etc. could transfigure the production of crops with high disease resistance and efficient nutrients utilization. In agriculture, the use of nanomaterials has gained acceptance due to their wide-range applications. However, their toxicity and bioavailability are the major hurdles for their massive employment. Undoubtedly, nanoparticles positively influence seeds germination, growth and development, stress management and post-harvest handling of vegetables and fruits. These nanoparticles may also cause toxicity in plants through oxidative stress by generation of excessive reactive oxygen species thus affecting the cellular biomolecules and targeting different channels. Nanoparticles have shown to exert various effects on plants that are mainly affected by various attributes such as physicochemical features of nanomaterials, coating materials for nanoparticles, type of plant, growth stages and growth medium for plants. This article discusses the interaction, accretion and toxicity of nanomaterials in plants. The factors inducing nanotoxicity and the mechanisms followed by nanomaterials causing toxicity are also instructed. At the end, detoxification mechanism of plant is also presented.
... Different studies have traced ZNP movement from mature leaves toward roots and grains in plants such as wheat, rice, and maize. However, the efficiency of translocation varies with particle properties such as size, coating, and plant species [69]. Smaller ZNPs below 10-20 nm that avoid filtration through plasmodesmata show enhanced long-distance transport. ...
... Electron microscopy techniques have detected ZNPs in various intracellular compartments following their uptake. ZNPs were observed in the cytoplasm, vacuoles, cell walls, starch granules, and nuclei of root cells in maize [69]. ZNPs were localized inside epidermal cells and vascular tissues in spinach after foliar exposure [14,71]. ...
Micronutrient deficiency poses a formidable challenge to global agriculture and human nutrition, particularly in cereal crop-dependent regions. Zinc, an essential micronutrient, plays a pivotal role in both plant growth and human health. Its deficiency in cereal crops results in diminished yields, inferior nutritional quality, and contributes to widespread human zinc deficiency, known as "hidden hunger." Conventional methods of zinc supplementation in agriculture have encountered limitations in terms of efficiency and environmental sustainability. Zinc nanoparticles (ZnPs), owing to their unique nanoscale properties, represent a novel approach to enhancing crop nutrition. Their high surface area facilitates improved interaction with plant roots, resulting in enhanced zinc uptake. In addition, ZnPs can be engineered for higher solubility in soil, enabling a readily available source of zinc for plant absorption throughout the growing season. Recent research has demonstrated the remarkable potential of ZnPs to effectively address zinc deficiencies in cereal crops. Studies have shown substantial increases in crop yields and nutritional quality, underscoring the promise of this innovative approach. Furthermore, the controlled release of zinc from nanoparticles reduces the environmental concerns associated with zinc runoff into water bodies, aligning with sustainable agricultural practices. This environmentally conscious approach ensures efficient utilization of resources while mitigating adverse ecological impacts. In an era where food security and nutrition are of paramount importance, the integration of ZnNPs into cereal crop management represents a promising avenue to simultaneously enhance crop yields, improve nutritional quality, and address the global issue of hidden hunger. This novel approach has the potential to revolutionize cereal crop micronutrient management, ulti-✶
... Decreased K levels may indicate membrane leakage in plants exposed to nCuO. Wang et al. (2012) showed that nCu increased K leakage in Zea mays L. root and shoot. Further, the combined effect of negative surface charge and higher surface-to-volume ratio of nCuO may promote complex formation with K + and reduce its bioavailability . ...
Increased impetus on the application of nano-fertilizers to improve sustainable food production warrants understanding of nanophytotoxicity and its underlying mechanisms before its application could be fully realized. In this study, we evaluated the potential particle size-dependent effects of soil-applied copper oxide nanoparticles (nCuO) on crop yield and quality attributes (photosynthetic pigments, seed yield and nutrient quality, seed protein, and seed oil), including root and seed Cu bioaccumulation and a suite of oxidative stress biomarkers, in soybean (Glycine max L.) grown in field environment. We synthesized three distinct sized (25 nm = S [small], 50 nm = M [medium], and 250 nm = L [large]) nCuO with same surface charge and compared with soluble Cu²⁺ ions (CuCl2) and water-only controls. Results showed particle size-dependent effects of nCuO on the photosynthetic pigments (Chla and Chlb), seed yield, potassium and phosphorus accumulation in seed, and protein and oil yields, with nCuO-S showing higher inhibitory effects. Further, increased root and seed Cu bioaccumulation led to concomitant increase in oxidative stress (H2O2, MDA), and as a response, several antioxidants (SOD, CAT, POX, and APX) increased proportionally, with nCuO treatments including Cu²⁺ ion treatment. These results are corroborated with TEM ultrastructure analysis showing altered seed oil bodies and protein storage vacuoles with nCuO-S treatment compared to control. Taken together, we propose particle size-dependent Cu bioaccumulation-mediated oxidative stress as a mechanism of nCuO toxicity. Future research investigating the potential fate of varied size nCuO, with a focus on speciation at the soil-root interface, within the root, and edible parts such as seed, will guide health risk assessment of nCuO.
Graphical Abstract
... Similarly, Ahmed et al. (2021) observed nano CuO produced a higher accumulation of Cu in cucumber plants than CuSO 4 in a neutral soil. Due to the casparian strip is not yet fully developed at the root apex, CuO NPs may move to the stele via apoplastic pathway and are then transported to the aerial parts via xylem (Wang et al. 2012). By the combination of bio-transmission electron microscopy and micro-CT analysis, Huang et al. (2022) found that CuO NPs entered Ipomoea aquatica Forssk. ...
The increasing use of copper oxide nano particles (nCuO) as nano-fertilizers and pesticides have raised concerns over their impact on soil environment and agricultural products. In this study, two nCuO with different shapes, namely spherical nCuO (CuO NPs) and tubular nCuO (CuO NTs), were selected to investigate their bioavailability and toxicity to pakchoi in two soils with different properties. At the meantime, CuO bulk particles (CuO BPs) and Cu(NO3)2 were used for comparison. Results showed that all the Cu treatments increased the DTPA extractable (DTPA-Cu) concentrations in GD soil (acidic) more than in HN soil (alkaline). The DTPA-Cu concentrations increased in the order of Cu(NO3)2 ≈ CuO NPs > CuO BPs ≈ CuO NTs in GD soil and Cu(NO3)2 > CuO NPs > CuO BPs ≈ CuO NTs in HN soil. While for the contents of Cu in the aerial parts of pakchoi, the order is CuO NPs > Cu(NO3)2 > CuO NTs ≈ CuO BPs in GD soil and CuO NPs ≈ Cu(NO3)2 > CuO BPs ≈ CuO NTs in HN soil. Only CuO NPs reduced pakchoi biomass in GD soil. There are no significant difference among CuO NPs, CuO BPs, and Cu(NO3)2 in reducing the chlorophyll contents in pakchoi in HN soil, whereas in GD soil, CuO NPs and CuO BPs led to significantly lower chlorophyll contents in pakchoi compared to Cu(NO3)2. Additionally, CuO NPs and Cu(NO3)2 increased Mn and Mo in pakchoi leaf in HN soil, while increased Zn in pakchoi leaf in GD soil. These results indicated that CuO NPs showed higher or comparable toxicity and bioavailability to pakchoi compared with Cu(NO3)2 depending on soil properties, and nCuO are more easily to be transferred from roots to the aerial parts than CuO BPs and Cu(NO3)2.
... Nanoparticles are de ned as particles with a size of less than 100 nm in at least one dimension [24]. Improvements in seed germination, seedling growth, biomass, total nitrogen content, protein and sugar contents, photosynthetic e ciency, and nutrient uptake are all documented as positive impacts of nanoparticles (NPs) on plant growth in crops such as cucumber, mung, spinach, wheat, and tomato [25][26][27][28][29]. Research shows that NPs can enter plant tissues and then move inside a plant's body systemically [30][31][32]. Among the di erent NPs used, ZnO NPs are currently the fourth most widely used in the world [33]. ...
Background: The present research is based on the hypothesis that foliar spray of zinc oxide nanoparticles (ZnO NPs) or application of biofertilizers such as vesicular arbuscular mycorrhiza (VAM) or arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSBs) are more e cient than generally used chemical fertilizers supplementation such as nitrogen (N), phosphorus (P) and supplementation of zinc (Zn). Methods: In this study, six mustard varieties, Brassica juncea var. Alankar, Pusa Jai Kisan, Varuna, Sakha, Rohini, and Pusa Bold were tested for their comparative growth responses. Out of the six tested varieties, only two screened varieties (Alankar and Rohini) were further tested for their comparative growth responses among the foliar spray of zinc oxide nanoparticles (ZnO NPs), soil-applied chemical fertilizers to supplement nitrogen (N) phosphorus (P) and zinc (Zn) as zinc sulfate and soil-applied biofertilizers as phosphate solubilizing bacteria (PSBs) and vesicular arbuscular mycorrhiza (VAM) or arbuscular mycorrhizal fungi (AMF). Results: The results revealed that out of these three treatments, ZnO NPs signi cantly (p≤0.05) increased the growth morphology of the two mustard varieties, followed by VAM/AMF and PSBs, which were followed by chemical supplementation of N, P, and Zn. The e ects were more pronounced in Alankar than in the Rohini variety of mustard. Conclusions: From the present study, it is concluded that foliar spray of ZnO NPs and the application of biofertilizers can be a potent alternative to costly chemical fertilizers in the cultivation of mustard crops. ABSTRACT Zinc
... Additionally, it is difficult to control plant diseases and pests because there are only a few management methods available, and it is also tough to identify diseases in time. Apart from this, traditional chemical fertilizers are less effective due to low nutrient use efficiency (NUE) (Elmer & White, 2016;Wang et al., 2012). Therefore it becomes important to adopt sustainable alternative ways to increase agricultural productivity by adopting nano-formulations for growth enhancement and productivity, and to control plant pests and diseases. ...
The global population is continuously expanding at an unpredictable rate, so food insecurity is the biggest threat that puts excessive pressure on the agriculture system to meet the food demand for everyone. It is imperative to develop and utilize innovative agriculture solutions to overcome food insecurity. The integration of nanotechnology and fertilizers has a significant advantage over conventional fertilizers due to enhanced nutrient uptake, nutrient use efficiency, and overall plant growth and development. The application of nanofertilizers in agriculture aims to improve the delivery and availability of nutrients to plants, thereby increasing crop yield and reducing environmental impacts. Nano-formulations can also be utilized to enhance plant resilience to various environmental stresses, like drought, salinity, and temperature extremes. It can act as signaling molecules or activators of stress-responsive genes, thereby helping plants to withstand adverse conditions by improving water and nutrient retention in the root zone and reducing the impact of drought or salinity stress. However, comprehensive research and validation are required to fully understand the potential benefits, risks, and long-term effects of these nanotechnology-based approaches on plants, ecosystems, and human health. The present chapter deals with the emerging field of nano nutrition and the application of nano macronutrients and nano micronutrients and their potential benefits.
... There are studies that have focused on the path followed by these ENMs after their application on plants, which varies with the mode of application. In a study conducted on maize, it was reported that the CuNPs were translocated through the xylem and phloem (Wang et al., 2012), and similarly, the vascular system of rice worked as the pathway for NP movement (Lin et al., 2010). ...
... 97 In earlier research, it was observed that maize seedlings exhibited toxic effects upon exposure to 100 mg L −1 of CuO-NPs. 98 More recently, it has been demonstrated that CeO 2 -NPs can inhibit the growth of soybean plants and decrease their yield by interrupting the nitrogen fixation. 80 In another study it was found that the use of VO 2 -NPs at concentrations of 10 mg L −1 or higher had toxic effects on pea seedlings. ...
Nanotechnology is a rapidly developing discipline that has the potential to transform the way we approach problems in a variety of fields, including agriculture. The utilization of nanotechnology in sustainable agriculture has gained popularity in recent years. Nanotechnology has various applications in agriculture, such as development of nanoscale materials and devices to boost agricultural productivity, enhance food quality and safety, improve the efficiency of water and nutrient usage, and decrease environmental pollution. Nanotechnology has proven to be highly beneficial in the field of agriculture, particularly in the development of nanoscale delivery systems for agrochemicals such as pesticides, fertilizers, and growth regulators. These nanoscale delivery technologies offer various benefits over conventional delivery systems, including better penetration and distribution, enhanced efficacy, and lower environmental impact. Encapsulating agrochemicals in nanoscale particles enables direct delivery to the targeted site in the plant, thereby reducing waste and minimizing off‐target effects. Plants are fundamental building blocks of all ecosystems and evaluating the interaction between nanoparticles (NPs) and plants is a crucial aspect of risk assessment. Therefore, this critical review aims to provide an overview of the latest advancements regarding the positive and negative effects of nanotechnology in agriculture. Additionally, we have also explored potential future research directions focused on ensuring the safe utilization of NPs in this field, which will lead us to sustainable development.
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... On the contrary, some investigators reported that some NFs had no effect on germination but did influence plants' growth. For example, graphene and CuO nanoparticles had no obvious effects on the germination of wheat and maize seeds, respectively, whereas root elongation was inhibited (Wang et al., 2012;Hu et al., 2014). Similarly, the effects of Fe 3 O 4 , TiO 2 , and carbon NPs were evaluated using cucumber seeds, and the tested NPs negatively affected root length, germination rate, and index (Mushtaq, 2011). ...
Fertilizers are important in the agricultural production system and have a critical function in intensifying food production and quality (Manikandan and Subramanian, 2016). It is applied by different methods, such as soil application, foliar feeding, and irrigation water (fertigation). However, the excessive use of chemical fertilizers has led to serious issues such as environmental pollution, soil degradation, reduction in soil organic matter, loss of soil carbon, disruption of the agricultural ecosystem, and soil quality depression (Dimkpa and Bindraban, 2018; Cui et al., 2020; Badawy et al., 2021).Hence, to control these economic and environmental barriers, innovative and highly efficient fertilizers are developed to improve nutrient retention for optimal growth and minimize environmental disruptions in globally sustainable agriculture.
Recently, nanotechnology has attracted strong intentions in the agriculture field to produce innovative nanofertilizers for increasing the efficacy and bioavailability of such fertilizers as well as reducing the loss of nutrients to the surrounding
environment (Salama et al., 2019; Seleiman et al., 2022). In addition, nanofertilizers offer a great surface area that increases photosynthesis rate, improves crop biomass, and helps the crop combat environmental stress. The choice of using agro-industry wastes for economic gain and waste utilization could provide food security, environmental safety, and sustainability to mankind. These natural materials are cheap, biodegradable, bioabsorbable, and nontoxic, and they contribute to soil quality improvement (Cerri et al., 2020; Perez Bravo and François, 2020). Application of NPs and NFs in soil and water remediation has offered a significant benefit in alleviating the detrimental effects of used chemicals on crops and increasing food quality and production. Abiotic stresses have a detrimental effect on the life cycle of plants and hamper crop growth and productivity (Elsheery et al., 2020; Manzoor et al., 2021; Yan et al., 2021; Seleiman et al., 2022). The minute size of NPs permits an efficient intersection of biological barriers in plants to remediate abiotic stresses (Gagliardi et al., 2021; Pereira et al., 2021; Van Nguyen et al., 2022). Application of nanofertilizers has been reported to improve germination attributes, nutrients availability, plants’ resistance to diseases, photosynthesis, chlorophyll formation, crop yield, and quality parameters (Ahmed et al., 2021; Badawy et al., 2021; El-Saadony et al., 2021a,b; El-Ashry et al., 2022).
The objectives of the present chapter are to provide the basic concepts and potential use of nanofertilizers as an essential source of nutrients that can maximize crop production and minimize nutrient losses compared to traditional chemical
fertilizers and to further outline the knowledge gaps in the role of NFs in mitigating abiotic stresses caused by climate change in plants and their potential limitations in respect of the environment and human health. Therefore, we have presented a novel body of information that represents the accumulation and integration of previous and updated research for scientists to use to evaluate and alleviate different kinds of abiotic stresses in crops with the aid of NFs.
... In addition, Xylem-phloem-xylem transport has been previously documented (Z. [99]), making redistribution of particles throughout plant possible via xylem-phloem loading, though xylem have restrictive nanometric pores unlike micrometric phloem pores [85]. However, another work reported no translocation of 37 nm nanoparticles in maize [10]. ...
... Indeed, in-plant transformation of nanomaterials has been demonstrated previously. 31 Molybdate in plants can undergo further transformation into organic forms, including Mo-COOH (organic acid-bound Mo, including Mo-malate and Mo-citrate, etc.) and Mo-thiol (thiol-bound Mo, including Mocysteine and Mo-GSH, etc.) in soybean (Figure 3b). These two forms of Mo can be generated in different plant compartments, including the xylem and phloem walls and cell walls (which are abundant in carboxyl groups), as well as in the cytosol, during the translocation of molybdate. ...
Molybdenum disulfide (nano-MoS2) nanomaterials have shown great potential for biomedical and catalytic applications due to their unique enzyme-mimicking properties. However, their potential agricultural applications have been largely unexplored. A key factor prior to the application of nano-MoS2 in agriculture is understanding its behavior in a complex soil–plant system, particularly in terms of its transformation. Here, we investigate the distribution and transformation of two types of nano-MoS2 (MoS2 nanoparticles and MoS2 nanosheets) in a soil–soybean system through a combination of synchrotron radiation-based X-ray absorption near-edge spectroscopy (XANES) and single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS). We found that MoS2 nanoparticles (NPs) transform dynamically in soil and plant tissues, releasing molybdenum (Mo) and sulfur (S) that can be incorporated gradually into the key enzymes involved in nitrogen metabolism and the antioxidant system, while the rest remain intact and act as nanozymes. Notably, there is 247.9 mg/kg of organic Mo in the nodule, while there is only 49.9 mg/kg of MoS2 NPs. This study demonstrates that it is the transformation that leads to the multifunctionality of MoS2, which can improve the biological nitrogen fixation (BNF) and growth. Therefore, MoS2 NPs enable a 30% increase in yield compared to the traditional molybdenum fertilizer (Na2MoO4). Excessive transformation of MoS2 nanosheets (NS) leads to the overaccumulation of Mo and sulfate in the plant, which damages the nodule function and yield. The study highlights the importance of understanding the transformation of nanomaterials for agricultural applications in future studies.
... On the other hand, some authors have contrary results to the present study. Authors like Wang et al. [27] reported an inhibition in the growth of maize plants. The inhibition tendencies of copper and copper oxide nanoparticles was further demonstrated in the reduced growth attributes and germination as reported by Nair et al. [28] in seed germination, growth in mustard seeds. ...
Copper is a nutrient required in small quantity by maize during growth, but it is not readily available to maize. Nanotechnology may however be helpful in the effective delivery of this nutrient. This study investigates the impact of copper nanoparticles (CuNPs) on growth attributes, stress enzymes, and the bioaccumulation potential of maize grown on CuNPs amended soils. The research was conducted in a screenhouse located at Kwara State University, Malete with the following coordinates (latitude 8 ⁰ 43' '' 8 and longitude 4 ⁰ 29' 11"). The Experiment was a Randomized Block Design experiment (RBD) with four seeds of maize planted separately in 2 kg of sandy loam soil pre-treated with 4, 8 and 12 mg/kg CuNPs while the control was the pots without CuNPs and these were replicated thrice making a total of 12 pots. Chlorophyll content, enzymatic antioxidants, bioaccumulation potential and proximate contents were determined following standard methods. Data obtained from the experiment were subjected to one-way Analysis of variance (ANOVA) while its mean value were analyzed with Duncan Multiple Range Test (DMRT) at P≤0.05. Bar chart was drawn using Origin Scientific Graphing and analysis software. CuNPs greatly enhanced plant growth, productivity, chlorophyll content, stress enzymes: [(Malondialdehyde (MDA), Catalase (CAT), Hydrogen peroxide (H 2 O 2 ) and Superoxide dismutase (SOD)] and bioaccumulation. This study concludes that at high concentrations, application of CuNPs on maize can hinder or arrest its growth and productivity as well as the death of the entire plants despite the fact that it is a micronutrient.
... The ENMs have significant surface effects, and changing their size and shape alters their properties (Kumar et al., 2022). In general, the higher the mass concentration and the smaller the size of ENMs, the greater the toxic effects on organisms are (Sun et al., 2022;Wang et al., 2012). Free exposure to ENMs is likely to affect the environment and human health, thus, researchers are increasingly interested in the pollution effects, the behavioral effects on soil, and the remediation mechanisms of ENMs in soil (Lewis et al., 2019). ...
... It has been shown that the transpiration rate positively influences NP uptake by plant roots. For example, transmission electron microscopy and energy dispersive analysis of xylem revealed that copper NPs travelled along with the water in the xylem, facilitating their translocation from roots to aerial parts of maize [116]. ...
Nanoparticles (NPs) have emerged as a revolutionary strategy in the field of agriculture, offering innovative solutions
for enhancing plant health, disease management, and sustainable crop production. This review summarizes the multifaceted
roles of NPs, synthesized chemically and biologically, in crop disease management, encompassing the NP
modulation of plant immunity against pathogens, mechanisms of NP uptake, and potential applications in disease
control. The integration of NPs as delivery vehicles for bioactive molecules, enabling targeted delivery of nutrients,
hormones, RNA interference molecules, and chemical protectants for growth regulation and disease management,
is also discussed in detail. The review also critically examines the safety and environmental considerations associated
with the potential application of NPs in the agriculture sector, including environmental toxicity, fate, and risks.
Future perspectives encompass precision agriculture, eco-friendly disease management, unraveling intricate plant-
NP interactions, and the necessity for responsible innovation. At the nexus of nanotechnology and agriculture, this
review underscores the transformative potential of NPs in revolutionizing plant health and crop disease management,
while highlighting the importance of responsible application to ensure sustainable and resilient agricultural systems.
... FM images provided evidence of the high abundance of PS nanoplastics in and near the stem's vascular system, supporting the leaf-to-root translocation through the vascular bundle, which is consistent with previous studies on engineered nanoparticles (e.g. Fe 2 O 3 , CuO, and carbon-coated magnetic nanoparticles) in plants (Cifuentes et al., 2010;Wang et al., 2012;Su et al., 2019). The phloem, which serves as the channel for transporting nutrients with water for plant growth, is believed to be the essential transport pathway for the movement of PS nanoplastics from leaves to roots, driven by the sourcesink pressure gradient (Cifuentes et al., 2010;Wang et al., 2013). ...
Oilseeds play a crucial role in the national economy. To enhance their productivity, innovative approaches such
as nano fertilizers are essential in the present-day context. The environmentally friendly synthesis approach was
employed to produce stabilized nano sulphur using Simarouba glauca leaf extractant. The characterization of the
nanoparticles involved identifying functional groups through various analytical techniques, including Raman
spectroscopy and UV–visible spectroscopy, as well as examining the electronic properties of sulphur nanoparticles.
Structural analysis of the sulphur nanoparticles revealed an orthorhombic configuration through
Powder X-ray diffraction tests. In-depth examinations using scanning electron microscopy and transmission
electron microscopy showcased particle sizes below 100 nm. In a laboratory experiment, sunflower seeds treated
with 600 ppm green-synthesized nano sulphur demonstrated remarkable root morphology and achieved the
highest root growth parameters, surpassing other concentration levels and control treatment. Importantly, the
environmentally friendly synthesized nanoparticles exhibited longer stability and greater efficacy when
compared to both chemically synthesized nanoparticles and conventional fertilizers.
Nanomaterials (NMs) have proven to be a game-changer in agriculture, showcasing their potential to boost plant growth and safeguarding crops. The agricultural sector has widely adopted NMs, benefiting from their small size, high surface area, and optical properties to augment crop productivity and provide protection against various stressors. This is attributed to their unique characteristics, contributing to their widespread use in agriculture. Human exposure from various components of agro-environmental sectors (soil, crops) NMs residues are likely to upsurge with exposure paths may stimulates bioaccumulation in food chain. With the aim to achieve sustainability, nanotechnology (NTs) do exhibit its potentials in various domains of agriculture also have its flip side too. In this review article we have opted a fusion approach using bibliometric based analysis of global research trend followed by a holistic assessment of pros and cons i.e. toxicological aspect too. Moreover, we have also tried to analyse the current scenario of policy associated with the application of NMs in agro-environment.
The treatment on pests relies heavily on the Stomach Toxicosis as the
mode of action is Nuclear Polyhedrosis Virus (NPV). For the administration
of lepidopterans at the field level, it was recommended. Virion bearing a
polyhedral structure that causes tree top disease, commonly known as
wipfelkrankheit, in larva. In comparison with chemical pesticides, residue,
resistance, and resurgence were not as commonly reported in this biocontrol
agent.
Nanotechnology offers a viable solution to enhancing agricultural sustainability by supporting seed germination and crop growth. Besides augmenting crop yields and mitigating the effects of abiotic stresses on crops, nanoparticles (NPs) can also serve as carriers to amplify the effectiveness of fertilizers and pesticides by facilitating their gradual or highly targeted release. However, application of NPs in agricultural systems can result in interaction with crops and pave the way for transfer along the food chain, which raises concerns for consumers. To address these matters, this article provides a comprehensive review of the tracking of various NPs delivered to crops through different uptake pathways. Three types of NPs (including inorganic, carbon-based, and organic NPs) are highlighted for uptake, transport, and their impact on crop growth in agricultural crops. NPs can enter the plant via seeds, roots, and leaves, while the translocation of NPs mainly involves the apoplastic and symplastic pathways. The influence of NPs on plant growth highly depends on the specific plant species as well as the type, size, charge, and concentration of NPs. NPs emit fluorescence through inherent photoluminescence or in combination with fluorescent dyes, which enables monitoring of their distribution within the crop. The benefits and challenges of NPs are discussed, establishing signposts for future research that will enable NPs to contribute to precise and sustainable agriculture.
Calcium (Ca) is an indispensable nutrient in plant development. Nanoparticles (NPs) are widely used in agricultural production, among which calcium L-aspartate nanoparticles (Ca(L-asp)-NPs), as a new type of Ca fertilizer,...
Silicon (Si) is a widely recognized beneficial element in plants. With the emergence of nanotechnology in agriculture, silicon nanoparticles (SiNPs) demonstrate promising applicability in sustainable agriculture. Particularly, the application of SiNPs has proven to be a high-efficiency and cost-effective strategy for protecting plant against various biotic and abiotic stresses such as insect pests, pathogen diseases, metal stress, drought stress, and salt stress. To date, rapid progress has been made in unveiling the multiple functions and related mechanisms of SiNPs in promoting the sustainability of agricultural production in the recent decade, while a comprehensive summary is still lacking. Here, the review provides an up-to-date overview of the synthesis, uptake and translocation, and application of SiNPs in alleviating stresses aiming for the reasonable usage of SiNPs in nano-enabled agriculture. The major points are listed as following: (1) SiNPs can be synthesized by using physical, chemical, and biological (green synthesis) approaches, while green synthesis using agricultural wastes as raw materials is more suitable for large-scale production and recycling agriculture. (2) The uptake and translocation of SiNPs in plants differs significantly from that of Si, which is determined by plant factors and the properties of SiNPs. (3) Under stressful conditions, SiNPs can regulate plant stress acclimation at morphological, physiological, and molecular levels as growth stimulator; as well as deliver pesticides and plant growth regulating chemicals as nanocarrier, thereby enhancing plant growth and yield. (4) Several key issues deserve further investigation including effective approaches of SiNPs synthesis and modification, molecular basis of SiNPs-induced plant stress resistance, and systematic effects of SiNPs on agricultural ecosystem.
Poor germination and seedlings growth can lead to significant economic losses for farmers, therefore, sustainable agricultural strategies to improve germination and early growth of crops are urgently needed. The objective of this work was to evaluate selenium nanoparticles (Se NPs) as nanopriming agents for tomato (Solanum lycopersicum) seeds germinated without stress conditions in both trays and Petri dishes. Germination quality, seedlings growth, synergism-antagonism of Se with other elements, and fate of Se NPs, were determined as function of different Se NPs concentrations (1, 10 and 50 ppm). Results indicated that the germination rate in Petri dishes improved with 10 ppm, while germination trays presented the best results at 1 ppm, increasing by 10 and 32.5%, respectively. Therefore, seedlings growth was measured only in germination trays. Proline content decreased up to 22.19% with 10 ppm, while for same treatment, the total antioxidant capacity (TAC) and total chlorophyll content increased up to 38.97% and 21.28%, respectively. Antagonisms between Se with Mg, K, Mn, Zn, Fe, Cu and Mo in the seed were confirmed. In the case of seedlings, the N content decreased as the Se content increased. Transmission Electron Microscopy (TEM) imaging confirmed that Se NPs surrounded the plastids of the seed cells. By this finding, it can be inferred that Se NPs can reach the embryo, which is supported by the antagonism of Se with important nutrients involved in embryogenesis, such as K, Mg and Fe, and resulted in a better germination quality. Moreover, the positive effect of Se NPs on total chlorophyll and TAC, and the negative correlation with proline content with Se content in the seed, can be explained by Se NPs interactions with proplastids and other organelles within the cells, resulting with the highest length and fresh weight when seeds were exposed to 1 ppm.
The study investigated the impact of copper oxide nanoparticles (CuONPs) on Fusarium wilt in chickpea. CuONPs, synthesized using coffee powder, were subjected to washing and sonication using Milli-Q water as the solvent during the purification process. Subsequently the nanoparticles were characterized through UV–vis spectroscopy, DLS, Zeta Potential and FTIR analysis. The NPs exhibited a size range of 85–100 nm with a zeta potential of −25.3 mV. Seven days old chickpea seedlings treated with different concentrations of CuONP (10, 25, 50 ppm) via root immersion showed a significant reduction in Fusarium infection severity. Treatment with 10 and 25 ppm CuONPs led to a remarkable 74.5% and 50% decrease in wilt incidence, along with increased root and shoot length, protein, tannin, phenolics, and flavonoid content in chickpea seedlings, grown in Fusarium infected soil. Enzyme activity (PAL, PPO, NR) was enhanced, while proline, H2O2, and MDA content decreased in 10 and 25 ppm CuONPs treated seedlings. A reduced activity of APX and SOD was also recorded in 10 and 25 ppm CuONPs treated seedlings. Chlorophyll content increased by 50.08% in 10 ppm treated seedlings but decreased with 25 and 50 ppm. The findings emphasize the protective role of copper oxide nanoparticles (CuONPs) at a lower concentration of 10 ppm against Fusarium wilt disease. This protective effect is manifested through the reduction of oxidative stress, decreased wilt incidence, and an increased biomass.
Molecular and Physiological Insights into Plant Stress Tolerance and Applications in Agriculture Part 2 is an edited volume that presents research on plant stress responses at both molecular and physiological levels. This volume builds on the previous volume to provide additional knowledge in studies on the subject.
Key Features
- Explains aspects of plant genetics central to research such as the role of cytosine methylation and demethylation in plant stress responses, and the importance of epigenetic genetics in regulating plant stress responses.
- Explores how Late Embryogenesis Abundant proteins affect plant cellular stress tolerance with an emphasis on their molecular mechanisms and potential implications.
- Focuses on beneficial microorganisms including rhizobacteria, endophytes, and mycorrhizal fungi, which are expected to be alternative fertilizers with the advantages of being cost-effective, toxin-free, and eco-friendly.
- Highlights the potential use of endophytic bacteria for protecting crops against pathogens
- Presents an in-depth analysis of the molecular level to understand the impact of ATP-binding cassette transporters on plant defense mechanisms with a discussion of the potential anti-pathogenic agents based on terpenes and terpenoids.
The content of the book is aimed at addressing UN SDG goals 2, 12, and 15 to achieve zero hunger and responsible consumption and production, and to sustainable use of terrestrial ecosystems, respectively.
This comprehensive resource is suitable for researchers, students, teachers, agriculturists, and readers in plant science, and allied disciplines.
Nanotechnology applications in plants are the driver for effective agricultural systems under different environmental conditions. The benefits and applications of nanoparticles (NPs) in plants have received substantial attention; it is of great concern to ensure sustainable and safer crop production. NPs are synthesized through biological, chemical, and physical methods and can be characterized by high-tech apparatus. However, biological synthesis is an eco-friendly and non-toxic route for the synthesis of NPs. Therefore, this chapter will describe the types of microorganisms (algae, bacteria, and fungi), and plants (trees, shrubs, and herbs) employed for the synthesis of different NPs. Moderation of abiotic stress on plants through NP applications has been a substantial tendency in recent agronomic research. Numerous causes of stress, such as flooding, light, drought, high and low temperature, salinity, darkness, microbial pathogens, and heavy metals, have been mitigated by NPs. This chapter will provide a complete overview of the application of nanotechnology in various aspects of plants, from NPs synthesis to targeted and meticulous delivery, uptake, recognition, translocation, interaction with plant cells, and the potential of NPs to mitigate complexes when applied to plant cells. Changes in gene expression, mechanisms of molecular defense, and proteomic and transcriptomic responses related to the improvement of plant tolerance by NPs under stress conditions will be described in this chapter. The chapter will critically assess what is and is not recognized in the field of nano-facilitated agriculture in response to abiotic stresses.
Nanoparticle transport into plants is an evolving field of research with diverse applications in agriculture and biotechnology. This article provides an overview of the challenges and prospects associated with the transport of nanoparticles in plants, focusing on delivery methods and the detection of nanoparticles within plant tissues. Passive and assisted delivery methods, including the use of roots and leaves as introduction sites, are discussed, along with their respective advantages and limitations. The barriers encountered in nanoparticle delivery to plants are highlighted, emphasizing the need for innovative approaches (e.g., the stem as a new recognition site) to optimize transport efficiency. In recent years, research efforts have intensified, leading to an evendeeper understanding of the intricate mechanisms governing the interaction of nanomaterials with plant tissues and cells. Investigations into the uptake pathways and translocation mechanisms within plants have revealed nuanced responses to different types of nanoparticles. Additionally, this article delves into the importance of detection methods for studying nanoparticle localization and quantification within plant tissues. Various techniques are presented as valuable tools for comprehensively understanding nanoparticle-plant interactions. The reliance on multiple detection methods for data validation is emphasized to enhance the reliability of the research findings. The future outlooks of this field are explored, including the potential use of alternative introduction sites, such as stems, and the continued development of nanoparticle formulations that improve adhesion and penetration. By addressing these challenges and fostering multidisciplinary research, the field of nanoparticle transport in plants is poised to make significant contributions to sustainable agriculture and environmental management.
Biomass is currently seen as a potential to be used as bioenergy resources. Its high availability and renewability generate extensive interest for further valorization. In Indonesia, research and development of transforming biomass into bioenergy via different pathways is expanding. Conversion of biomass via physical/mechanical, biochemical, and thermochemical offers produces bioenergy in the form of liquid (i.e., biodiesel, bioethanol, and bio-oil), gasses (i.e., biogas and syngas), and solid (i.e., biopellets, biochars, and briquettes). These types of bioenergy are essential for substituting fossil-based fuels, hence have positive impacts on reducing carbon emissions and climate change. Different mechanisms of process occur during the conversion. Specific measures to the influencing factors are crucial to ensure the optimum performance efficacy. This chapter discusses various bioenergy routes from biomass substrates from the process’ mechanisms to examples, in particular anaerobic digestion, transesterification, fermentation, densification, and thermochemical pathways.
Contaminated soil is one of today’s most difficult environmental issues, posing serious hazards to human health and the environment. Contaminants, particularly micro-nano plastics, have become more prevalent around the world, eventually ending up in the soil. Numerous studies have been conducted to investigate the interactions of micro-nano plastics in plants and agroecosystems. However, viable remediation of micro-nano plastics in soil remains limited. In this review, a powerful in situ soil remediation technology known as phytoremediation is emphasized for addressing micro-nano-plastic contamination in soil and plants. It is based on the synergistic effects of plants and the microorganisms that live in their rhizosphere. As a result, the purpose of this review is to investigate the mechanism of micro-nano plastic (MNP) uptake by plants as well as the limitations of existing MNP removal methods. Different phytoremediation options for removing micro-nano plastics from soil are also described. Phytoremediation improvements (endophytic-bacteria, hyperaccumulator species, omics investigations, and CRISPR-Cas9) have been proposed to enhance MNP degradation in agroecosystems. Finally, the limitations and future prospects of phytoremediation strategies have been highlighted in order to provide a better understanding for effective MNP decontamination from soil.
Graphical Abstract
Iron (Fe) oxide nanoparticles (NPs) improve crop growth. However, the comparative effect of root and foliar-applied different sources of Fe oxide NPs on plant performance at morphological and physiological levels still needs to be discovered. In this study, we characterized the growth and physiological responses of hydroponic-cultured maize seedlings to four sources of Fe (i.e., α-Fe2O3, γ-Fe2O3, Fe3O4 NPs, and bulk Fe3O4) and two application methods (root vs. foliar). Results showed that Fe concentration in root and shoot increased by elevating the level of NPs from 100 mg L−1 to 500 mg L−1. Overall, the responses of maize seedlings to different sources of Fe oxide NPs were as
follows: Fe3O4 > γ-Fe2O3 > α-Fe2O3 > bulk Fe3O4. The application of Fe at concentrations ranging from 100 mg L−1 to 500 mg L−1 had no significant effects on various growth parameters of maize, including biomass, chlorophyll content, and root length. Iron oxide NPs increased the plant biomass by 23–37% by root application, whereas it was 5–9% by foliar application. Chlorophyll contents were increased by 29–34% and 18–22% by foliar and root applications, respectively. The non-significant
response of reactive oxygen species (i.e., superoxide dismutase, catalase, and peroxidase) suggested optimum maize performance for supplementing Fe oxide NPs. A confocal laser scanning microscope suggested that Fe oxide NPs entered through the epidermis and from the cortex to the endodermis. Our results provide a scientific basis that the root application of Fe3O4 at the rate of 100 mg L−1 is a promising approach to obtain higher maize performance and reduce the quantity of fertilizer used in agriculture to minimize environmental effects while improving crop productivity and quality. These findings demonstrated the tremendous potential of Fe NPs as an environmentally friendly and
sustainable crop approach.
Sustainable crop production is the key to global food security. With progress in industrialization, threats of pollution have increased, and one of them is metal toxicity. An increase in metal concentration in soil, over the prescribed safety limits, affects crop productivity and enhances the chances of food toxicity. To overcome the toxic effects of metal adulteration, it is necessary to understand crop responses to metal toxicity. In this chapter, the physiological, biochemical, and morphological changes in crop responses to metal toxicity are discussed. Moreover, various management options to alleviate metal toxicity are also discussed. This chapter will provide a deep understanding of the metal toxicity in plants and also its possible remediation.
Human health is being seriously affected by nutrient deficiencies in food crops, particularly in underdeveloped and remote areas. The availability of sufficient and safe nutrition to prevent malnutrition and cure various diseases may be an aspect of improving human health. To overcome the present issue; biofortification, a method to enhance nutritional status of food crops, can address the issue of hidden hunger. Nanotechnology may contribute to improving the quality of food through biofortification and may prove to be an effective and sustainable remedy to this issue by foliar application of essentials nutrients (Zn, Cu, Fe and Se) nanoparticles and their nano-based fertilizers in the soil to improve nutrient deficiency. This review highlights the use of nanomaterials in biofortification of plant nutrients, specifically their absorption and translocation, which have positive outcomes for alleviation of hidden hunger and improving nutrient levels. Additionally, the significance of nano-biofortification is discussed in relation to the COVID-19 pandemic and the problem of nutritional security. By understanding the various issues related to the safe use of nanoparticles and their future prospects, we can improve their effectiveness in fulfilling dietary needs through nano-biofortification.
The control of plant’s optimal nutrition for long-term crop quality and productivity is one of the top areas of agricultural research emphasis. A new trend of the industry embraces the use of nano-fertilizers that increase the agricultural output and leads to the bio-fortification of the crops. Different nano-carriers have been reported in the literature that is being utilized for transferring the nutrients to plants more effectively than their conventional way of applications. In various ways, these nano-carriers increase the availability of both micro- and macronutrients for plants along with their own supportive behavior for the soil and crops. The present study is designed to present a comprehensive overview of novel developing strategies that are increasing nutrient availability for crops, including their effects on crop growth, yield, and fortification; their required concentration and application rate; their mechanism of action; unfavorable outcomes; and research gaps. The article is concluded with remarks on the future opportunities of the presented work.
BACKGROUND
To address the challenges of food security for the ever‐increasing population, the emergence of nanotechnology provides an alternate technology of choice for the production of safer pesticides which serves as a substitute for conventional fertilizer. The antidrug resistance of Xanthomonas oryzae pv. oryzae (Xoo) and build‐up of chemicals in the environment has made it necessary to find alternative safe techniques for effective disease management. Hence, in this study, copper oxide nanoparticles (CuONPs) were produced by green synthesis using a Hibiscus rosa‐sinensis L. flower extract.
RESULTS
The characterization of CuONPs using ultraviolet–visible spectrophotometry, scanning electron microscopy with an energy‐dispersive spectrum profile, Fourier transform infrared spectroscopy, and X‐ray diffraction ascertained the presence of CuONPs, which were nanorods of 28.1 nm. CuONPs significantly obstructed the growth and biofilm development of Xoo by 79.65% and 79.17% respectively. The antibacterial mechanism of CuONPs was found to result from wounding the cell membrane, giving rise to an exodus of intracellular content and generation of oxidative reactive oxygen species that invariably inhibited Xoo respiration and growth. A toxicity study under greenhouse conditions revealed that CuONPs significantly increased growth variables and the biomass of rice, and reduced bacterial leaf blight. Application of CuONPs on Arabidopsis improved the chlorophyll fluorescence parameters; the ΦPSII was significantly increased by 152.05% in comparison to the control.
CONCLUSION
Altogether, these results suggest that CuONPs in low concentration (200.0 μg mL⁻¹) are not toxic to plants and can serve as nano‐fertilizers and nano‐pesticides. © 2023 Society of Chemical Industry.
In spite of the mounting concerns, current understanding of the extent and mechanisms of phytotoxicity of manufactured nanomaterials remains limited. Here we show that in Arabidopsis thaliana, ultra-small anatase TiO(2) nanoparticles cause reorganization and elimination of microtubules followed by the accelerated and 26S proteasome-dependent degradation of tubulin monomers. Similar to other microtubule-disrupting agents, TiO(2) nanoparticles induce isotropic growth of root cells. Because microtubules are essential for the normal function of all eukaryotic cells, these results reveal a potentially important consequence of environmental pollution by this widely used nanomaterial.
The development of nanodevices for agriculture and plant research will allow several new applications, ranging from treatments with agrochemicals to delivery of nucleic acids for genetic transformation. But a long way for research is still in front of us until such nanodevices could be widely used. Their behaviour inside the plants is not yet well known and the putative toxic effects for both, the plants directly exposed and/or the animals and humans, if the nanodevices reach the food chain, remain uncertain. In this work we show that magnetic carbon-coated nanoparticles forming a biocompatible magnetic fluid (bioferrofluid) can easily penetrate through the root in four different crop plants (pea, sunflower, tomato and wheat). They reach the vascular cylinder, move using the transpiration stream in the xylem vessels and spread through the aerial part of the plants in less than 24 hours. Accumulation of nanoparticles was detected in wheat leaf trichomes, suggesting a way for excretion/detoxification. This kind of studies is of great interest in order to unveil the movement and accumulation of nanoparticles in plant tissues for assessing further applications in the field or laboratory.
A laboratory investigation was conducted to determine whether colloidal suspensions of inorganic nanoparticulate materials of natural or industrial origin in the external water supplied to the primary root of maize seedlings (Zea mays L.) could interfere with water transport and induce associated leaf responses. Water flow through excised roots was reduced, together with root hydraulic conductivity, within minutes of exposure to colloidal suspensions of naturally derived bentonite clay or industrially produced TiO2 nanoparticles. Similar nanoparticle additions to the hydroponic solution surrounding the primary root of intact seedlings rapidly inhibited leaf growth and transpiration. The reduced water availability caused by external nanoparticles and the associated leaf responses appeared to involve a rapid physical inhibition of apoplastic flow through nanosized root cell wall pores rather than toxic effects. Thus: (1) bentonite and TiO2 treatments also reduced the hydraulic conductivity of cell wall ghosts of killed roots left after hot alcohol disruption of the cell membranes; and (2) the average particle exclusion diameter of root cell wall pores was reduced from 6.6 to 3.0 nm by prior nanoparticle treatments. Irrigation of soil-grown plants with nanoparticle suspensions had mostly insignificant inhibitory effects on long-term shoot production, and a possible developmental adaptation is suggested.
Thioredoxins, the ubiquitous small proteins with a redox active disulfide bridge, are important regulatory elements in plant metabolism. Initially recognized as regulatory proteins in the reversible light activation of key photosynthetic enzymes, they have subsequently been found in the cytoplasm and in mitochondria. The various plant thioredoxins are different in structure and function. Depending on their intracellular location they are reduced enzymatically by an NADP-dependent or by a ferredoxin (light)-dependent reductase and transmit the regulatory signal to selected target enzymes through disulfide/dithiol interchange reactions. In this review we summarize recent developments that have provided new insights into the structures of several components and into the mechanism of action of the thioredoxin systems in plants.
Nanomaterials are engineered structures with at least one dimension of 100 nanometers or less. These materials are increasingly
being used for commercial purposes such as fillers, opacifiers, catalysts, semiconductors, cosmetics, microelectronics, and
drug carriers. Materials in this size range may approach the length scale at which some specific physical or chemical interactions
with their environment can occur. As a result, their properties differ substantially from those bulk materials of the same
composition, allowing them to perform exceptional feats of conductivity, reactivity, and optical sensitivity. Possible undesirable
results of these capabilities are harmful interactions with biological systems and the environment, with the potential to
generate toxicity. The establishment of principles and test procedures to ensure safe manufacture and use of nanomaterials
in the marketplace is urgently required and achievable.
Nanotechnology is a major innovative scientific and economic growth area, which may present a variety of hazards for environmental and human health. The surface properties and very small size of nanoparticles and nanotubes provide surfaces that may bind and transport toxic chemical pollutants, as well as possibly being toxic in their own right by generating reactive radicals. There is a wealth of evidence for the harmful effects of nanoscale combustion-derived particulates (ultrafines), which when inhaled can cause a number of pulmonary pathologies in mammals and humans. However, release of manufactured nanoparticles into the aquatic environment is largely an unknown. This review addresses the possible hazards associated with nanomaterials and harmful effects that may result from exposure of aquatic animals to nanoparticles. Possible nanoparticle association with naturally occurring colloids and particles is considered together with how this could affect their bioavailability and uptake into cells and organisms. Uptake by endocytotic routes are identified as probable major mechanisms of entry into cells; potentially leading to various types of toxic cell injury. The higher level consequences for damage to animal health, ecological risk and possible food chain risks for humans are also considered based on known behaviours and toxicities for inhaled and ingested nanoparticles in the terrestrial environment. It is concluded that a precautionary approach is required with individual evaluation of new nanomaterials for risk to the health of the environment. Although current toxicity testing protocols should be generally applicable to identify harmful effects associated with nanoparticles, research into new methods is required to address the special properties of nanomaterials.
We recently identified multivesicular bodies (MVBs) as prevacuolar compartments (PVCs) in the secretory and endocytic pathways to the lytic vacuole in tobacco (Nicotiana tabacum) BY-2 cells. Secretory carrier membrane proteins (SCAMPs) are post-Golgi, integral membrane proteins mediating endocytosis in animal cells. To define the endocytic pathway in plants, we cloned the rice (Oryza sativa) homolog of animal SCAMP1 and generated transgenic tobacco BY-2 cells expressing yellow fluorescent protein (YFP)-SCAMP1 or SCAMP1-YFP fusions. Confocal immunofluorescence and immunogold electron microscopy studies demonstrated that YFP-SCAMP1 fusions and native SCAMP1 localize to the plasma membrane and mobile structures in the cytoplasm of transgenic BY-2 cells. Drug treatments and confocal immunofluorescence studies demonstrated that the punctate cytosolic organelles labeled by YFP-SCAMP1 or SCAMP1 were distinct from the Golgi apparatus and PVCs. SCAMP1-labeled organelles may represent an early endosome because the internalized endocytic markers FM4-64 and AM4-64 reached these organelles before PVCs. In addition, wortmannin caused the redistribution of SCAMP1 from the early endosomes to PVCs, probably as a result of fusions between the two compartments. Immunogold electron microscopy with high-pressure frozen/freeze-substituted samples identified the SCAMP1-positive organelles as tubular-vesicular structures at the trans-Golgi with clathrin coats. These early endosomal compartments resemble the previously described partially coated reticulum and trans-Golgi network in plant cells.
We studied the response of maize (Zea mays L. cv. Anjou 256) to a simultaneous, but separated supply of ammonium and nitrate (localized supply, LS). A split-root system was used to supply half of the roots with ammonium and the other half with nitrate. A homogeneously distributed supply of both nitrogen forms (HS) was the control treatment. Seedlings were grown for 12 d from the two-leaf to the three-leaf stage in hydroponics at three pH levels (4, 5·5 and 7). The total N concentration was 3 mol m-3. The split-root system was established by removing the seminal root system and using only four nodal roots per plant. Total root length and root surface area were recorded automatically with a modified Delta- T area meter. Other morphological root traits (such as main axis length and diameter, number, density, and length of laterals) were recorded manually. Uptake of ammonium and nitrate was measured by the depletion of the nutrient solution. As compared with LS, HS was superior in shoot and root DM, total root length and root surface area, ammonium and nitrate uptake and shoot nitrogen concentration, irrespective of pH level. This indicates that, also under field conditions, mixed ammonium and nitrate fertilization is only beneficial to plant growth if both N forms are evenly distributed in the soil. At both HS and LS, ascending pH increased the ammonium:nitrate uptake ratio. At LS, declining pH induced a considerable shift in the distribution of root DM, root length, and root surface area the nitrate-fed compartment.
Highly dispersed copper oxide (CuO) nanoparticles with an average size of 6 nm have been successfully prepared by a novel quick-precipitation method. The as-prepared CuO nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–Visible absorption spectroscopy and BET nitrogen adsorption. The results show that the as-prepared CuO nanoparticles have high dispersion and narrow size distribution. The influence of reaction conditions on morphology of CuO nanocrystals was discussed. Spherical, ellipsoidal and needle-shaped CuO nanocrystals can be obtained simply by varying the reaction temperature and controlling the addition of NaOH.
Plants of three commercial cultivars of Hordeum vulgaris L. (Barberousse, Gerbel, Panda) were continuously exposed to two concentrations of SO2 (40±5 and 117±20 ppb) against a control (charcoal-filtered air). Experiments were performed in fumigation chambers. Fumigation was started 9 days after seeding and plant material was harvested after 48 days. In none of the three cultivars did visible symptoms of injury appear on the leaves after exposure to SO2, while they all showed a reduction in plant height and dry matter of shoots and roots and a significant increase in the shoot/root dry weight ratios depending on the cultivars. The time course of conductivity, and K+ Ca2+ and sugar effluxes were determined for 24 h. Leaves from cvs Gerbel and Panda exposed to SO2 exhibited a progressive increase in conductivity, and in Ca2+ and sugar efflux (expressed as percentages of their total effluxes). Plusmn; efflux of the three cultivars and conductivity in cv. Barberousse increased only after 24 h incubation. A relative leakage ratio (RLR) was calculated from the UV absorption at 280 nm after 24 h incubation of the leaf strips and the total 280 nm UV absorption, obtained after liquid N2 killing of the tissues. The RLR was well correlated with the total amino acids and sugars found in the leachate and can be used as a test for determining the tissue response to SO2.
Lors de leur passage d’éléments nutritifs, en solution dans le sol, vers le mécanisme actif d’absorption, localisé a la surface
symplasmique, les ions, absorbés au plasmalemma des cellules de racine, doivent en premier lieu passer à travers les espaces
libres de la membrane cellulaire. Cet article discute les propriétés des racines au point de vue de l’échange de cations en
termes d’intéractions ioniques à l’interieur de l’apoplasme racinaire et les conséquences de telles intéractions sur l’accumulation
d’ions par la plante.
Les espaces libres dans la membrane cellulaire des racines sont considérés comme un libre continuum diffusible de la solution
ionique externe, mais ses propriétés sont modifiées par les charges ioniques des substances localisées à l’intérieur de la
matrice de la membrane cellulaire. Le rôle de ces espaces libres dans le transport radial des ions est examiné et les intéractions
ioniques complexes qui se jouent a l’intérieur des espaces libres est discuté. Il est conclu que plus de recherche est nécéssaire
pour élucider clairement le rôle des espaces libres dans l’accumulation des ions par les plantes. Cependant, les resultats
indiquent que, sous certaines conditions expérimentales, les intéractions ioniques à l’intérieur des espaces libres des racines
influencent qualitativement la composition ionique des plantes.
Samples of ash from municipal refuse incinerators in six Connecticut towns as well as samples of incinerated sewage sludge were collected during 1988 and 1989. The samples were analyzed for pH, metal content by HNO3 + H2O2 digestion, extractable metals by solvents including NaOAc, DTPA, H2CO3 and H2O. Two samples were examined for metals that could be leached by H2O from laboratory columns. Most ash samples were highly alkaline and their pH changed slowly, decreasing by about two pH units over a 6-week period. The variability in metal content of ash from different incinerators was similar to that observed in samples obtained from the same facility at different times. Only a portion of the metals were extracted by the solvents in the order NaOAc > DTPA > H2CO3 > H2O. The relative amounts of the total metals in the ash that could be extracted with specific solvents varied widely, suggesting different chemical forms in different ashes. After the initial removal of large concentrations of metals in the leachates from laboratory columns over 2 to 3 days, leaching of metals continued at extremely low concentrations that were generally below drinking water standards.
Maize roots were grown between 1 mm glass beads on which a pressure of 40 kPa was applied. The roots were supplied with a constant flow of aerated nutrient solution. Compared with roots grown in a nutrient solution, the impeded crown roots showed a reduction in length of about 75%, whereas the diameter was about 50% increased.
These changes in root morphology have been attributed to changes in cell wall structure of the cortex cells, which also occur as a result of the influence of ethylene.
It is suggested that ethylene acts as an intermediate factor in the effect of mechanical impedance on root growth.
Whole-plant carbohydrate partitioning is the process whereby carbon assimilated through photosynthesis is distributed from the leaves to the rest of the plant by transport through the phloem. Allocation of carbohydrates underlies all aspects of plant growth and crop yield. Yet, in spite of the extremely critical role this process has on plant function and development, very little is known about the genetic and molecular mechanisms that control carbohydrate partitioning. Plants employ different strategies for importing photoassimilates into the phloem. Recent findings have uncovered plasticity both in the modes of phloem loading and carbohydrates translocated. Sugar transporters play essential roles in phloem loading in many plant species, but it is not known how they are regulated. Studies into the transcriptional and post-translational regulation of sugar transporters provide insights into the cellular mechanisms governing their expression and functions. Recent exciting potential breakthroughs include the observations that sucrose transporter multimerization, subcellular localization and activity are regulated by reduction/oxidation (redox) potentials, and the identification of a protein that physically interacts with multiple sugar transporters, modulating their activities. In addition, redox-regulation influences starch synthesis in both source and sink tissues. Tantalizing clues are emerging relating to redox-regulation of phloem function and of long-distance carbohydrate partitioning.
The successful application of various nanoplatforms in medicine under in vitro conditions has generated some interest in agri-nanotechnology. This technology holds the promise of controlled release of agrochemicals and site targeted delivery of various macromolecules needed for improved plant disease resistance, efficient nutrient utilization and enhanced plant growth. Processes such as nanoencapsulation show the benefit of more efficient use and safer handling of pesticides with less exposure to the environment that guarantees ecoprotection. The uptake efficiency and effects of various nanoparticles on the growth and metabolic functions vary differently among plants. Nanoparticle mediated plant transformation has the potential for genetic modification of plants for further improvement. Specifically, application of nanoparticle technology in plant pathology targets specific agricultural problems in plant–pathogen interactions and provide new ways for crop protection. Herein we reviewed the delivery of nanoparticulate materials to plants and their ultimate effects which could provide some insights for the safe use of this novel technology for the improvement of crops.
The acute toxicity of CuO and ZnO nanoparticles in artificial freshwater (AFW) and in natural waters to crustaceans Daphnia magna and Thamnocephalus platyurus and protozoan Tetrahymena thermophila was compared. The L(E)C50 values of nanoCuO for both crustaceans in natural water ranged from 90 to 224 mg Cu/l and were about 10-fold lower than L(E)C50 values of bulk CuO. In all test media, the L(E)C50 values for both bulk and nanoZnO (1.1–16 mg Zn/l) were considerably lower than those of nanoCuO. The natural waters remarkably (up to 140-fold) decreased the toxicity of nanoCuO (but not that of nanoZnO) to crustaceans depending mainly on the concentration of dissolved organic carbon (DOC). The toxicity of both nanoCuO and nanoZnO was mostly due to the solubilised ions as determined by specific metal-sensing bacteria.
Extensive application of metal nanoparticles is attracting more attention because of their potential environmental risks. Many studies have focused on the uptake of metal nanoparticles (NPs) by plant, but the adsorption of nanoparticles on root surface is often mistakenly regarded as their uptake. This study optimized the methods to distinguish the adsorption and uptake of CuO-NPs on the wheat root by applying different metal competing ions (Na+, Mg2+, and La3+), surfactant (i.e., sodium dodecyl benzene sulfonate, SDBS), or complexing agents like NaOAc and Na4EDTA, as well as ultrasonic technique. The results indicated that some CuO-NPs is strongly adsorbed on the plant root surface, and part of them by mechanical adhesion. Competing ions could not desorb the CuO-NPs from the root surface, while NaOAc and Na4EDTA well dissolved the adsorbed CuO-NPs. In addition, the uptake and adsorption of CuO-NPs increased with increasing exposure concentrations of CuO-NPs in the range of 5-200 mg/L. The amount of CuO-NPs adsorption is always lower than that of their uptake.
Engineered nanoparticles, due to their unique electrical, mechanical, and catalytic properties, are presently found in many commercial products and will be intentionally or inadvertently released at increasing concentrations into the natural environment. Metal- and metal oxide-based nanomaterials have been shown to act as mediators of DNA damage in mammalian cells, organisms, and even in bacteria, but the molecular mechanisms through which this occurs are poorly understood. For the first time, we report that copper oxide nanoparticles induce DNA damage in agricultural and grassland plants. Significant accumulation of oxidatively modified, mutagenic DNA lesions (7,8-dihydro-8-oxoguanine; 2,6-diamino-4-hydroxy-5-formamidopyrimidine; 4,6-diamino-5-formamidopyrimidine) and strong plant growth inhibition were observed for radish (Raphanus sativus), perennial ryegrass (Lolium perenne), and annual ryegrass (Lolium rigidum) under controlled laboratory conditions. Lesion accumulation levels mediated by copper ions and macroscale copper particles were measured in tandem to clarify the mechanisms of DNA damage. To our knowledge, this is the first evidence of multiple DNA lesion formation and accumulation in plants. These findings provide impetus for future investigations on nanoparticle-mediated DNA damage and repair mechanisms in plants.
Adverse effect of engineered nanoparticles (NPs) on the aquatic environment and organisms has recently drawn much attention. This paper reports on the toxicity of CuO NPs to juvenile carp (Cyprinus carpio) and their distribution in the fish. CuO NPs and its counterpart bulk particles (BPs) (10, 50, 100, 200, 300, 500 and 1000 mg L(-1)) exhibited no acute toxicity (96 h), while during the 30 day sub-acute toxicity test, carp growth was significantly inhibited by CuO NPs (100 mg L(-1)) in comparison to control, CuO BPs and Cu(2+) groups. CuO NPs (or released Cu(2+) ions inside the fish body) could distribute in various tissues/organs and followed an order: intestine>gill>muscle>skin and scale>liver>brain. For time-related distribution, Cu content (expressed on a dry mass basis) in intestine, gill and liver increased faster (within 1 day) and they had obviously higher Cu content than other tissues/organs at all exposure times. CuO NPs could be excreted by carp to lower their toxicity. Cholinesterase activity was inhibited during CuO NPs exposure, suggesting NPs exposure could have potential neurotoxicity, and free Cu(2+) ions dissolved inside the carp body was responsible for the cholinesterase inhibition. Finally, actual suspended NPs concentrations should be used instead of initially added concentrations whenever possible in nanotoxicity studies.
The presence and release of nanoparticles (NPs) into the environment have important implications for human health and the environment. A critical aspect of the risk assessment of nanoparticles is to understand the interactions of manufactured nanoparticles with plants. In this study, the uptake and distribution characteristics of two types of ceria nanoparticles with sizes of ca. 7 nm and 25 nm in cucumber plants were investigated using a radiotracer method and other techniques. With increasing concentration of the nanoparticles, concentration dependent absorption by the plant roots was noticed, but the majority of the particles only loosely adhered to the root surface. The seedlings treated with 7 nm ceria particles showed significantly higher ceria contents in both roots and shoots than those exposed to 25 nm ceria particles at all test concentrations (2, 20, and 200 mg L(-1)). Only very limited amounts of ceria nanoparticles could be transferred from the roots to shoots because the entry of nanoparticles into the roots was difficult. However, the results of tissue distributions of ceria nanoparticles in the plants and two dimensional distributions of the particles in the leaves imply that once they have entered into the vascular cylinder, ceria nanoparticles could move smoothly to the end of the vascular bundle along with water flow. To the best of our knowledge, this is the first detailed study of uptake and distribution of metal oxide nanoparticles in plants.
This is the first study investigating the toxicity of nanoparticles (NPs) to algae in the presence of dissolved organic matter (DOM). Suwannee river fulvic acid (SRFA), a type of DOM, could significantly increase the toxicity of CuO NPs to prokaryotic alga Microcystis aeruginosa. Internalization of CuO NPs was observed for the first time in the intact algal cells using high resolution transmission electron microscopy (HRTEM), and the cell uptake was enhanced by SRFA. A fast Fourier transformation (FFT)/inversed FFT (IFFT) process revealed that a main form of intracellular NPs was Cu(2)O, and an intracellular environment may reduce CuO into Cu(2)O. The internalization behavior alone did not seem to pose a hazard to membrane integrity as shown from the flow cytometry data. Elevated CuO nanotoxicity by SRFA was related to a combination of a lesser degree of aggregation, higher Cu(2+) release, and enhanced internalization of CuO NPs.
Induced formation of metal nanoparticles in living plants is poorly understood. The sites for the reduction of Ag(+) and Au(3+) to Ag(0) and Au(0) metal nanoparticles in vivo in plants were investigated in order to better understand the mechanism of the reduction processes. Brassica juncea was grown hydroponically, followed by growth in solutions of AgNO(3), [Ag(NH(3))(2)]NO(3) or HAuCl(4). Harvested plants were sectioned and studied by transmission electron microscopy. Total metal content was analysed by atomic absorption spectroscopy. The chemical state of the metals was determined by X-ray absorption spectroscopy. Nanoparticles of Ag(0) and Au(0) were found in leaves, stem, roots and cell walls of the plants at a concentration of 0.40% Ag and 0.44% Au in the leaves. Particles which were approximately spherical were formed with sizes of 2-100 nm. The sites of the most abundant reduction of metal salts to nanoparticles were the chloroplasts, regions of high reducing sugar (glucose and fructose) content. We propose that these sugars are responsible for the reduction of these metals and other metal salts with reduction potentials over +0.16 V and that the amount of reducing sugar present or produced determines the quantity of metal nanoparticles that may be formed.
Major barriers to delivery of biomolecules are crossing the cellular membranes and achieving a high cytoplasmic concentration by circumventing entrapment into endosomes and other lytic organelles. Motivated by such aim, we have investigated the capability of multiwalled carbon nanotubes (MWCNTs) to penetrate the cell membrane of plant protoplasts (plant cells made devoid of their cell walls via enzymatic treatment) and studied their internalization mechanism via confocal imaging and TEM techniques. Our results indentified an endosome-escaping uptake mode of MWCNTs by plant protoplasts. Moreover, short MWCNTs (<100 nm) were observed to target specific cellular substructures including the nucleus, plastids, and vacuoles. These findings are expected to have a significant impact on plant cell biology and transformation technologies.
The effect of water-soluble fullerene C(70)(C(COOH)(2))(4-8) on plant growth was investigated, using the transgenic seedling lines expressing fluorescent makers. The retarded roots with shortened length and loss of root gravitropism were observed for seedlings grown in the fullerene-containing medium. Fluorescence imaging revealed the abnormalities of root tips in hormone distribution, cell division, microtubule organization, and mitochondrial activity. The study of the inhibitory effects at the cellular level provides new information on the phytotoxicity mechanism of fullerene.
We propose a novel combination of high-throughput luminescent bacterial tests for the evaluation of the reactive oxygen species (ROS)-generating potential of engineered nanoparticles (eNPs) and the role of solubilised metal ions in this process. The set of tests consists of differently engineered recombinant Escherichia coli strains: (1) a new sensor strain, which bioluminescence is induced by superoxide anions; (2) six recombinant E. coli strains (superoxide dismutase (sod) single, double and triple mutants and a respective wild-type strain), transformed with luxCDABE genes responding to toxic compounds by decreasing their luminescence; and (3) three strains in which bioluminescence is specifically induced by bioavailable metals (Cu, Zn and Ag). The applicability of this battery of tests in profiling oxidative potential of eNPs was evaluated on nTiO2, nCuO, nZnO and nAg (25, 30, 70 and <100 nm, respectively) NPs and fullerenes. As controls for the size or solubility, the bulk formulations (bTiO2, bCuO and bZnO) and soluble salts (ZnSO4, CuSO4 and AgNO3) were also analysed. Bacterial toxicity tests showed that nCuO was four-fold more toxic, and nAg was 15-fold more toxic to triple sod mutant than to wild type (2-h EC50 values were 8.1 and 2.0 mg Cu l−1, respectively, and 46 and 3.1 mg Ag l−1, respectively). Formation of ROS by nCuO and nAg was proved by superoxide anion-inducible strain. The metal sensor bacteria showed that the ROS formation by CuO NPs was caused by solubilised Cu ions, but in case of nAg, particles also had an effect. nZnO was remarkably more toxic to sod triple mutant than to wild type strain (2-h EC50 were 4.5 and 54 mg Zn l−1, respectively). Fullerenes inhibited the bioluminescence of sod triple mutant at 3,882 mg l−1 but had no effect on the wild-type strain even at 20,800 mg l−1. Nano and bTiO2 showed some effect on viability of bacteria only at high concentrations (>4,000 mg l−1) although nTiO2 (but not bTiO2) induced the bioluminescence of the superoxide anion sensing bacteria starting from 100 mg l−1. Thus, our innovative combined approach is expected to provide more consistent and informative data concerning the general toxicity, ROS-production potential and also solubilisation of metals in the case of metallic NPs.
Figure
This study discusses the potential of nTiO2, nCuO, nZnO, nAg and fullerene to generate reactive oxygen species and release metal ions as analysed by a combined set of bacterial tests.
While few publications have documented the uptake of nanoparticles in plants, this is the first study describing uptake and distribution of the ultrasmall anatase TiO(2) in the plant model system Arabidopsis. We modified the nanoparticle surface with Alizarin red S and sucrose and demonstrated that nanoconjugates traversed cell walls, entered into plant cells, and accumulated in specific subcellular locations. Optical and X-ray fluorescence microscopy coregistered the nanoconjugates in cell vacuoles and nuclei.
The effects of five nanomaterials (multiwalled carbon nanotubes [MWCNTs], Ag, Cu, ZnO, Si) and their corresponding bulk counterparts on seed germination, root elongation, and biomass of Cucurbita pepo (zucchini) were investigated. The plants were grown in hydroponic solutions amended with nanoparticles or bulk material suspensions at 1000 mg/L. Seed germination was unaffected by any of the treatments, but Cu nanoparticles reduced emerging root length by 77% and 64% relative to unamended controls and seeds exposed to bulk Cu powder, respectively. During a 15-day hydroponic trial, the biomass of plants exposed to MWCNTs and Ag nanoparticles was reduced by 60% and 75%, respectively, as compared to control plants and corresponding bulk carbon and Ag powder solutions. Although bulk Cu powder reduced biomass by 69%, Cu nanoparticle exposure resulted in 90% reduction relative to control plants. Both Ag and Cu ion controls (1-1000 mg/L) and supernatant from centrifuged nanoparticle solutions (1000 mg/L) indicate that half the observed phytotoxicity is from the elemental nanoparticles themselves. The biomass and transpiration volume of zucchini exposed to Ag nanoparticles or bulk powder at 0-1000 mg/mL for 17 days was measured. Exposure to Ag nanoparticles at 500 and 100 mg/L resulted in 57% and 41% decreases in plant biomass and transpiration, respectively, as compared to controls or to plants exposed to bulk Ag. On average, zucchini shoots exposed to Ag nanoparticles contained 4.7 greater Ag concentration than did the plants from the corresponding bulk solutions. These findings demonstrate that standard phytotoxicity tests such as germination and root elongation may not be sensitive enough or appropriate when evaluating nanoparticle toxicity to terrestrial plant species.
In commercial growth of horticultural plants in greenhouses, high financial losses are being suffered due to the so-called thick root syndrome (TRS), a phenomenon characterized by severe deterioration of the root system. The early symptoms of TRS in cucumber ( Cucumis sativus L.) are strongly curving roots that are swollen and superficially damaged. Research focused on ethylene, as both the culture practice of cucumber and the known effects of ethylene on root growth point to a possible role for this phytohormone in TRS. Ethylene induced root curvature and swelling as well as damage of the epidermal layer and outer cortex of roots of cucumber plants similar to TRS symptoms. Formation of root hairs was stimulated and root elongation was also severely inhibited by exogenous ethylene. However, based on experiments with the ethylene inhibitor α-aminoisobutyric acid (AIB), a causal relation between ethylene and TRS in cucumber is doubted. Copyright 1999 Annals of Botany Company
The first evidence on the uptake, accumulation, and generational transmission of natural organic matter (NOM)-suspended carbon nanoparticles in rice plants, was provided. Newly harvested rice seeds were incubated in Petri dishes that contained 15 mL of different concentrations of C70-NOM and MWNT-NOM in rice generated buffer. Results show black aggregates in the seeds and roots, which is less frequent in stems and leaves, indicating that the sequence of nanoparticles uptake is results from seeds and roots to the stems and leaves. C70 is found to be present in or near the stems vascular systems and less in the leaves seeds due to the multiplied uptake rates. Two sets of rice seeds germinated show that the seeds start germination to first produce shoots and then stems, while after 3 weeks, the seeds are no longer able to provide sufficient nutrients for the newly germinated plants, detached from the seedlings.
We have investigated the capability of single-walled carbon nanotubes (SWNTs) to penetrate the cell wall and cell membrane of intact plant cells. Confocal fluorescence images revealed the cellular uptake of both SWNT/fluorescein isothiocyanate and SWNT/DNA conjugates, demonstrating that SWNTs also hold great promise as nanotransporters for walled plant cells. Moreover, the result suggested that SWNTs could deliver different cargoes into different plant cell organelles.
Increasing application of nanotechnology highlights the need to clarify nanotoxicity. However, few researches have focused on phytotoxicity of nanomaterials; it is unknown whether plants can uptake and transport nanoparticles. This study was to examine cell internalization and upward translocation of ZnO nanoparticles by Lolium perenne (ryegrass). The dissolution of ZnO nanoparticles and its contribution to the toxicity on ryegrass were also investigated. Zn2+ ions were used to compare and verify the root uptake and phytotoxicity of ZnO nanoparticles in a hydroponic culture system. The root uptake and phytotoxicity were visualized by light scanning electron, and transmission electron microscopies. In the presence of ZnO nanoparticles, ryegrass biomass significantly reduced, root tips shrank, and root epidermal and cortical cells highly vacuolated or collapsed. Zn2+ ion concentrations in bulk nutrient solutions with ZnO nanoparticles were lower than the toxicity threshold of Zn2+ to the ryegrass; shoot Zn contents under ZnO nanoparticle treatments were much lower than that under Zn2+ treatments. Therefore, the phytotoxicity of ZnO nanoparticles was not directly from their limited dissolution in the bulk nutrient solution or rhizosphere. ZnO nanoparticles greatly adhered on to the rootsurface. Individual ZnO nanoparticles were observed present in apoplast and protoplast of the root endodermis and stele. However, translocation factors of Zn from root to shoot remained very low under ZnO nanoparticle treatments, and were much lower than that under Zn2+ treatments, implying that little (if any) ZnO nanoparticles could translocate up in the ryegrass in this study.
Xylem sap from broccoli (Brassica oleracea L. cv. Calabrais), rape (Brassica napus L. cv. Drakkar), pumpkin (Cucurbita maxima Duch. cv. gelber Zentner) and cucumber (Cucumis sativus L. cv. Hoffmanns Giganta) was collected by root pressure exudation from the surface of cut stems of healthy, adult plants. Total protein concentrations were in the range of 100 microg ml(-1). One-dimensional gel electrophoresis (SDS-PAGE) resulted in 10-20 visible protein bands in a molecular mass range from 10 to 100 kDa. The main bands were cut out, digested with trypsin, and analysed using tandem mass spectrometry. Fifty bands resulted in amino acid sequence information that was used to perform database similarity searches. Sequences from 30 bands showed high homology to proteins present in databases. Among them, we found mostly peroxidases, but could also identify the lectin-like xylem protein XSP30, a glycine-rich protein, serine proteases, an aspartyl protease family protein, chitinases, and a lipid transfer protein-like polypeptide. Sequence analysis predicted apoplastic secretion signals for all database entries similar to the partial xylem protein sequences. This and the lack of cross-reactivity with phloem protein-specific antibodies suggest that the proteins really originate from the xylem and do not result from phloem contamination. Most of the highly similar proteins probably function in repair and defence reactions. Some of the most abundant proteins (peroxidases, chitinases, serine proteases) were present in xylem exudate of all species analysed, often in more than one band. This indicates an important basic role of these proteins in maintaining xylem function.
Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Effects of five types of nanoparticles (multi-walled carbon nanotube, aluminum, alumina, zinc, and zinc oxide) on seed germination and root growth of six higher plant species (radish, rape, ryegrass, lettuce, corn, and cucumber) were investigated. Seed germination was not affected except for the inhibition of nanoscale zinc (nano-Zn) on ryegrass and zinc oxide (nano-ZnO) on corn at 2000 mg/L. Inhibition on root growth varied greatly among nanoparticles and plants. Suspensions of 2000 mg/L nano-Zn or nano-ZnO practically terminated root elongation of the tested plant species. Fifty percent inhibitory concentrations (IC50) of nano-Zn and nano-ZnO were estimated to be near 50mg/L for radish, and about 20mg/L for rape and ryegrass. The inhibition occurred during the seed incubation process rather than seed soaking stage. These results are significant in terms of use and disposal of engineered nanoparticles.
Transition metal transporters are of central importance in the plant metal homeostasis network which maintains internal metal concentrations within physiological limits. An overview is given of the functions of known transition metal transporters in the context of the unique chemical properties of their substrates. The modifications of the metal homeostasis network associated with the adaptation to an extreme metalliferous environment are illustrated in two Brassicaceae metal hyperaccumulator model plants based on cross-species transcriptomics studies. In a comparison between higher plants and unicellular algae, hypotheses are generated for evolutionary changes in metal transporter complements associated with the transition to multicellularity.
Rapid development and application of nanomaterials and nanotechnology make assessment of their potential health and environmental impacts on humans, non-human biota, and ecosystems imperative. Here we show that pumpkin plants (Cucurbita maxima), grown in an aqueous medium containing magnetite (Fe3O4) nanoparticles, can absorb, translocate, and accumulate the particles in the plant tissues. These results suggest that plants, as an important component of the environmental and ecological systems, need to be included when evaluating the overall fate, transport and exposure pathways of nanoparticles in the environment.
Phytotoxicity of nanoparticles: Inhibition of seed germination and root growth Heavy metals and their leachability in incinerator ash. Water Air Soil Poll
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Ecotoxicity of nanoparticles of CuO and ZnO in natural water Distribution of CuO nanoparticles in juvenile carp (Cyprinus carpio) and their potential toxicity
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Growth and solute leakage in Hordeum valgare exposed to long-term fumigation with low concentrations of SO 2 Xylem sap protein composition is conserved among different plant species
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Silver and gold nanoparticles in plants: sites for the reduction to metal Schü rmann, P.; Jacquot, J. P. Plant thioredoxin systems revisited Current perspectives on the regulation of whole-plant carbohydrate partitioning
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