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Relationship Between Nanoparticles and Higher Plants
Full text linkThe 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’t 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, β-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
Green synthesis of Ag nanoparticles using plant metabolites
No full textNano-biotechnology is one of the most promising areas in modern nanoscience and technology. In this
emerging area of research, nanoparticles (NPs) play an important role since the large-scale production and huge numbers
of utilization. Gold and silver nanoparticles are among the most extensively studied nanomaterials, since they show high
stability and low chemical reactivity in comparison to other metals. They are commonly synthesized using toxic chemical
reducing agents able to reduce metal ions into uncharged NPs and/or high energy supplied procedures. The most
commonly used method for the synthesis of NPs requires toxic chemicals like N,N-dimethyl formamide (DMF) or
trisodium citrate, but recently a green technique, based on natural reducing agents, has been suggested to substitute the
nature-unfriendly chemical methods. Many scientific works put in evidence the efficacy of plant extracts to reduce metal
salts into the respective NPs, but this process lacks a clear control of NPs shapes and dimensions, since many different
metabolites present into the extracts could participate to the process. This paper aims to clarify the reducing action of
single pure natural compounds usually present in plant tissues and to obtain a stable and reproducible protocol for NPs
synthesis
POPULATION GENETIC STRUCTURE OF PERENNIAL RYEGRASS (LOLIUM PERENNE) IS HIGHLY CORRELATED WITH PLANT AVAILABLE COPPER
Full text linkEvidences of genotoxicity and phytotoxicity in Zea mays and Hordeum vulgare exposed to CeO2 and TiO2 nanoparticles
No full textAre the reducing sugars the driving force for Ag nanoparticles biosynthesis in living plants?
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effects of cerium and titanium oxide nanoparticles in soil on the nutrient composition of barley (Hordeum vulgare L.) kernels
Full text linkThe implications of metal nanoparticles (MeNPs) are still unknown for many food crops. The purpose of this study was to evaluate the effects of cerium oxide (nCeO2) and titanium oxide (nTiO2) nanoparticles in soil at 0, 500 and 1000 mg· kg−1 on the nutritional parameters of barley (Hordeum vulgare L.) kernels. Mineral nutrients, amylose, β-glucans, amino acid and crude protein (CP) concentrations were measured in kernels. Whole flour samples were analyzed by ICP-AES/MS, HPLC and Elemental CHNS Analyzer. Results showed that Ce and Ti accumulation under MeNPs treatments did not differ from the control treatment. However, nCeO2 and nTiO2 had an impact on composition and nutritional quality of barley kernels in contrasting ways. Both MeNPs left β-glucans unaffected but reduced amylose content by approximately 21%. Most amino acids and CP increased. Among amino acids, lysine followed by proline saw the largest increase (51% and 37%, respectively). Potassium and S were both negatively impacted by MeNPs, while B was only affected by 500 mg nCeO2· kg−1. On the contrary Zn and Mn concentrations were improved by 500 mg nTiO2· kg−1, and Ca by both nTiO2 treatments. Generally, our findings demonstrated that kernels are negatively affected by nCeO2 while nTiO2 can potentially have beneficial effects. However, both MeNPs have the potential to negatively impact malt and feed production
Biochar influence on Ce nanoparticles leaching and plant uptake in Lepidium sativum from a packed-lysimeter experiment.
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