Relationship Between Nanoparticles and Higher Plants

The study of relationship between vascular plants and nanoparticles was subdivided in two branches, in particular the first part of the research was focused on the investigation the plants capacity to synthetize nanoparticles (NPs) inside their tissues and which are the principal molecules involved in the process. Subsequently the principal aim of the research was focused on the study of possible toxic effects caused by the NPs when they enter in contact with the plants during their first development stages and along their entire life cycle. In order to investigate the plant capacity to synthetize NPs B. juncea, M. sativa and F. rubra plants were exposed for 24 hours in a hydroponic system to a solution of silver nitrate (AgNO3) at 1000 ppm. All three plant species show high uptake and translocation of Ag. The ultrastructural analyses and microanalyses of electron dense aggregates present in roots stems and leaves in all three plant species confirm the presence of AgNPs and for the first time was confirmed in F. rubra. The content of reducing sugars and antioxidant substances analyzed were quite different between species thus suggesting it is unlikely that a single substance is responsible for this process. The focus of experiments move to the investigation of possible toxic effects caused by the interaction of NPs with plants during their first development stages. For this purpose H. vulgare seedlings were exposed to increasing concentration of cerium (Ce) and titanium (Ti) NPs for 24 hours in order to check the possible genotoxic effects and H. vulgare seeds for 7 days for testing the possible phytotoxic effects. Difference between treated plants with CeNPs and controls were observed in RAPD band pattern and a reduction in the in cell division, while the TiNPs resulted ineffective. The phytotoxic effects were checked at cellular level by monitoring the oxidative stress in term of reactive oxygen species (ROS) generation and ATP content. Again the CeNPs result to have an effect on these parameters while the TiNPs resulted ineffective. The materials were used also for check the NPs uptake and their translocation in the seedling tissues. The NPs uptake were confirmed at root level for both NPs whereas the NPs translocation weren\u2019t confirmed but only the elements. The toxic effects of NPs were checked along the entire plant life cycle, for this purpose H. vulgare plants were grown to physiological maturity in soil enriched with either Ce NPs or TiNPs at increasing concentration and their combination. The growth cycle of CeNPs and TiNPs plants was about 10 days longer than the controls. In CeNPs treated plants the number of tillers, leaf area and the number of spikes per plant were reduced whereas TiNPs stimulated plant growth and compensated for the adverse effects of nCeO2. Concentrations of Ce and Ti in aboveground plant fractions were minute. The fate of nanomaterials within the plant tissues was different. Crystalline TiNPs aggregates were detected within the leaf tissues whereas CeNPs was not present in the form of nanoclusters. The kernels obtained from the previous experiment were used to check if the treatment have got some effects on their nutritional quality. For this purpose the mineral nutrients, amylose, \u3b2-glucan, amino acid and crude protein (CP) concentrations in H. vulgare kernels were measured. Ce and Ti accumulation were not enhanced by MeNPs trereatments. However, CeNPs and TiNPs impacted the nutritional quality of H. vulgare kernels in contrasting ways. Both MeNPs reduced amylose and increased amino acid and CP content. Potassium and S were both negatively impacted by MeNPs, while B only under at lower concentration of CeNPs. On the contrary Zn and Mn concentrations were improved under lower concentration TiNPs and Ca at both nTiO2 treatments

Application of Nanotechnology in Agriculture: Assessment of TiO2 Nanoparticle Effects on Barley

Many aspects associated with the application of nanotechnology to agricultural activities are still unknown. In particular, there is not enough information on nanotoxicology in crops and we do not know the fate of nanoparticles in crops. Multiple experiments were carried out to study the effects of titanium oxide nanoparticles (nTiO2) on barley (Hordeum vulgare). Germinating seeds were exposed to 0, 500, 1000, and 2000 mg l−1nTiO2. Seed germination percentage, mitotic index, root elongation, and Ti concentration in seedlings were observed. In a greenhouse experiment, plants of barley were grown to physiological maturity in control soil and soil enriched with 500 and 1000 mg nTiO2 mg kg−1, respectively. The duration of the growth cycle and the plant biomass was influenced by nTiO2 compared to control plants. Concentrations of Ti were not very high with the exception of roots. However, the nTiO2 soil amendment had an impact on composition and nutritional quality of barley grains. Concentrations of Ca, Mn, and Zn in kernels were increased by nTiO2 treatments. Concentration of amino acids was affected by the treatments as well. nTiO2 treatments have the potential to influence the food chain and processing and economics of barley

Influence of Cerium Oxide Nanoparticles on Two Terrestrial Wild Plant Species

Most current studies on the relationships between plans and engineered nanomaterials (ENMs) are focused on food crops, while the effects on spontaneous plants have been neglected so far. However, from an ecological perspective, the ENMs impacts on the wild plants could have dire consequences on food webs and ecosystem services. Therefore, they should not be considered less critical. A pot trial was carried out in greenhouse conditions to evaluate the growth of Holcus lanatus L. (monocot) and Diplotaxis tenuifolia L. DC. (dicot) exposed to cerium oxide nanoparticles (nCeO2). Plants were grown for their entire cycle in a substrate amended with 200 mg kg1 nCeO2 having the size of 25 nm and 50 nm, respectively. nCeO2 were taken up by plant roots and then translocated towards leaf tissues of both species. However, the mean size of nCeO2 found in the roots of the species was different. In D. tenuifolia, there was evidence of more significant particle aggregation compared to H. lanatus. Further, biomass variables (dry weight of plant fractions and leaf area) showed that plant species responded differently to the treatments. In the experimental conditions, there were recorded stimulating effects on plant growth. However, nutritional imbalances for macro and micronutrients were observed, as well

Influence of Cerium Oxide Nanoparticles on Two Terrestrial Wild Plant Species

Most current studies on the relationships between plans and engineered nanomaterials (ENMs) are focused on food crops, while the effects on spontaneous plants have been neglected so far. However, from an ecological perspective, the ENMs impacts on the wild plants could have dire consequences on food webs and ecosystem services. Therefore, they should not be considered less critical. A pot trial was carried out in greenhouse conditions to evaluate the growth of Holcus lanatus L. (monocot) and Diplotaxis tenuifolia L. DC. (dicot) exposed to cerium oxide nanoparticles (nCeO2). Plants were grown for their entire cycle in a substrate amended with 200 mg kg1 nCeO2 having the size of 25 nm and 50 nm, respectively. nCeO2 were taken up by plant roots and then translocated towards leaf tissues of both species. However, the mean size of nCeO2 found in the roots of the species was different. In D. tenuifolia, there was evidence of more significant particle aggregation compared to H. lanatus. Further, biomass variables (dry weight of plant fractions and leaf area) showed that plant species responded differently to the treatments. In the experimental conditions, there were recorded stimulating effects on plant growth. However, nutritional imbalances for macro and micronutrients were observed, as well

Changes in Physiological and Agronomical Parameters of Barley (Hordeum vulgare) Exposed to Cerium and Titanium Dioxide Nanoparticles

The aims of our experiment were to evaluate the uptake and translocation of cerium and titaniumoxide nanoparticles and to verify their effects on the growth cycle of barley (Hordeum vulgare L.). Barley plants were grown to physiological maturity in soil enriched with either 0, 500 or 1000 mg kg1 cerium oxide nanoparticles (nCeO2) or titanium oxide nanoparticles (nTiO2) and their combination. The growth cycle of nCeO2 and nTiO2 treated plants was about 10 days longer than the controls. In nCeO2 treated plants the number of tillers, leaf area and the number of spikes per plant were reduced respectively by 35.5%, 28.3% and 30% (p \ua4 0.05). nTiO2 stimulated plant growth and compensated for the adverse effects of nCeO2. Concentrations of Ce and Ti in aboveground plant fractions were minute. The fate of nanomaterials within the plant tissues was different. Crystalline nTiO2 aggregates were detected within the leaf tissues of barley, whereas nCeO2 was not present in the form of nanoclusters

Focal Stroke in the Developing Rat Motor Cortex Induces Age- and Experience-Dependent Maladaptive Plasticity of Corticospinal System

Motor system development is characterized by an activity-dependent competition between ipsilateral and contralateral corticospinal tracts (CST). Clinical evidence suggests that age is crucial for developmental stroke outcome, with early lesions inducing a "maladaptive" strengthening of ipsilateral projections from the healthy hemisphere and worse motor impairment. Here, we investigated in developing rats the relation between lesion timing, motor outcome and CST remodeling pattern. We induced a focal ischemia into forelimb motor cortex (fM1) at two distinct pre-weaning ages: P14 and P21. We compared long-term motor outcome with changes in axonal sprouting of contralesional CST at red nucleus and spinal cord level using anterograde tracing. We found that P14 stroke caused a more severe long-term motor impairment than at P21, and induced a strong and aberrant contralesional CST sprouting onto denervated spinal cord and red nucleus. The mistargeted sprouting of CST, and the worse motor outcome of the P14 stroke rats were reversed by an early skilled motor training, underscoring the potential of early activity-dependent plasticity in modulating lesion outcome. Thus, changes in the mechanisms controlling CST plasticity occurring during the third postnatal week are associated with age-dependent regulation of the motor outcome after stroke

Focal Stroke in the Developing Rat Motor Cortex Induces Age- and Experience-Dependent Maladaptive Plasticity of Corticospinal System

Motor system development is characterized by an activity-dependent competition between ipsilateral and contralateral corticospinal tracts (CST). Clinical evidence suggests that age is crucial for developmental stroke outcome, with early lesions inducing a “maladaptive” strengthening of ipsilateral projections from the healthy hemisphere and worse motor impairment. Here, we investigated in developing rats the relation between lesion timing, motor outcome and CST remodeling pattern. We induced a focal ischemia into forelimb motor cortex (fM1) at two distinct pre-weaning ages: P14 and P21. We compared long-term motor outcome with changes in axonal sprouting of contralesional CST at red nucleus and spinal cord level using anterograde tracing. We found that P14 stroke caused a more severe long-term motor impairment than at P21, and induced a strong and aberrant contralesional CST sprouting onto denervated spinal cord and red nucleus. The mistargeted sprouting of CST, and the worse motor outcome of the P14 stroke rats were reversed by an early skilled motor training, underscoring the potential of early activity-dependent plasticity in modulating lesion outcome. Thus, changes in the mechanisms controlling CST plasticity occurring during the third postnatal week are associated with age-dependent regulation of the motor outcome after stroke

Influence of hydroxyapatite nanoparticles on germination and plant metabolism of tomato (Solanum lycopersicum L.): Preliminary evidence

The Nutrient Use Efficiency in intensive agriculture is lower than 50% for macronutrients. This feature results in unsustainable financial and environmental costs. Nanofertilizers are a promising application of nanotechnology in agriculture. The use of nanofertilizers in an efficient and safe manner calls for knowledge about the actual effects of nanoproducts on the plant metabolism and eventually on the carrier release kinetics and nutrient accumulation. Hydroxyapatite (Ca10(PO4)6(OH)2) nanoparticles (nHA) have an interesting potential to be used as nanofertilizers. In this study, the effects of different nHA solutions stabilized with carboxymethylcellulose (CMC) were evaluated on germination, seedling growth, and metabolism of Solanum lycopersicum L., used as model species. Our observations showed that the percentage germination of S. lycopersicum is not influenced by increasing concentrations of nHa, while root elongation is strongly stimulated. Tomato plants grown in hydroponics in the presence of nHA have not suffered phytotoxic effects. We conclude that nHA had nontoxic effects on our model plant and therefore it could be used both as a P supplier and carrier of other elements and molecules