Search

Nanoparticles (NPs) have been progressively applied in the last decades, which may impact the environment. Synthesis of pigments and nutrient elements uptake by plants can also be affected by NPs. The influence of lanthanum oxide nanoparticles (La2O3 NPs) on growth, pigments synthesis and nutrient elements uptake by Pfaffia glomerata (Spreng.) Pedersen, a medicinal plant native in South America, were evaluated in the present study. P. glomerata plantlets were cultivated for 28 days in the absence (control) and presence of 100, 200 and 400 mg L−1 of La2O3 NPs or bulk-La2O3 (b-La2O3) at the same cultivation conditions. Root development, aerial part growth and pigments concentration in plants were affected by b-La2O3 and La2O3 NPs, mainly by La2O3 NPs. Calcium, Cu, Fe, K, La, Mg, Mn, Mo, P, S and Zn determination in stems and leaves revealed drastically and similar decrease of nutrient elements in plants cultivated in presence of 400 mg L−1 of La2O3 NPs or b-La2O3. Alteration of nutrient elements concentration was also observed for the other treatments. Mapping of elements (using laser ablation inductively coupled plasma mass spectrometry) in leaves of plants submitted to treatment with 400 mg L−1 of b-La2O3 or La2O3 NPs showed differences in the distribution of elements, indicating distinct effects of b-La2O3 and La2O3 NPs on P. glomerata. As such, this study demonstrated that La2O3 NPs may impact plants growth.

Nanoparticles (NPs) have been progressively applied in the last decades, which may impact the environment. Synthesis of pigments, growing, and nutrient element uptake by plants can also be affected by NPs. The influence of lanthanum oxide nanoparticles (La

Accumulation of lanthanum oxide nanoparticles (La2O3NPs) in the femur bone of rats after 30 days of oral administration was explored. Also, the influence of La2O3NPs on macro and trace elements in the rats’ femur bone was assessed. Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical spectrometry (ICP OES) were used for total element determination in the bone after decomposition while laser ablation-ICP-MS (LA-ICP-MS) was used to investigate element distribution (bio-imaging) in the bone. Some differences in element concentrations in the bone between the rats treated with La2O3NPs at 1.0 mg kg−1 (T1), 10.0 mg kg−1 (T2), and 100 mg kg−1 (T3) body weight (bw) and the control rats (CTR) were observed. More differences were observed in the bone of rat treated with 10.0 mg kg−1 La2O3NPs bw. However, the highest change observed was for Mg, which concentration ranged from 5230 ± 12 μg kg−1 for the CTR group to 4130 ± 138 μg kg−1 for the T3 group. Minor changes were observed for Ba, Ca, Cr, Cu, Fe, Mg, Na, Pb, Sr, and Zn between CTR and animals treated with La2O3NPs at the different levels of concentration. It was possible to observe from LA-ICP-MS analysis that La2O3NPs were accumulated only on the surface of the bone, not deeper than about 5 μm. LA-ICP-MS allowed also to investigate the distribution of La and the other elements in a cross section of the femur bone head, where higher amounts of the elements are present at the external part of the bone. Therefore, it was demonstrated that La2O3NPs are incorporated on the surface of the bone and it has a small influence on some of the other elements evaluated.

The production and use of nanoparticles (NPs) in different fields increased in the last years. However, some NPs have toxicological properties, making these materials potential emerging pollutants. Therefore, it is important to investigate the uptake, transformation, translocation, and deposition of NPs in plants. In this work, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and micro X-ray fluorescence (μ-XRF) were used to investigate the uptake and translocation of La2O3 NPs to stem and leaves of Pfaffia glomerata (Spreng.) Pedersen after in vitro cultivation of plants in the presence of 400 mg L-1 of La2O3 NPs. By using LA-ICP-MS and μ-XRF, image of the spatial distribution of La in the leaves was obtained, where higher concentration of La was observed in the main veins. Differences in the signal profile of La in leaves of plants cultivated in the presence of bulk La2O3 (b-La2O3) and La2O3 NPs were observed. Sharp peaks of La indicated that NPs were transported to the stems and leaves of plants treated with La2O3 NPs. Both LA-ICP-MS and μ-XRF techniques have shown to be useful for detecting NPs in plants, but LA-ICP-MS is more sensitive than μ-XRF and allowed better detection and visualization of La distribution in the whole leaf.

Copper (Cu) is an essential element for plants, especially in photosynthesis, as it is required for plastocyanin function in electron transfer reactions at thylakoid membranes. In Arabidopsis thaliana, Cu deficiency leads to the Cu economy response, in which plants prioritize Cu usage by plastocyanin in detriment of non-essential cupric proteins. In rice (Oryza sativa), however, this response has not been characterized. Rice OsHMA5 is a Cu xylem-loading transporter involved in Cu translocation from roots to shoots, as suggested by the analysis of oshma5 mutant plants. Aiming to understand how rice plants respond to Cu deficiency and how decreased Cu translocation to shoots can affect this response, we characterized the physiological and molecular responses of WT and oshma5 plants under control and Cu deficiency treatments. We found evidence that shoots of oshma5 plants are more prone to Cu deficiency compared to shoots of WT plants, as demonstrated by decreased chlorophyll and Cu concentrations, and electron transport rate. Gene expression analysis revealed that Cu high-affinity transporters OsCOPT1 and OsCOPT5, along with a set of miRNAs and three Cu/Zn superoxide dismutases are responsive to Cu deficiency in both WT and oshma5 plants, suggesting their involvement in the Cu economy response. However, Fe superoxide dismutase was not up-regulated in rice, indicating a difference compared to the A. thaliana Cu economy model. Therefore, we provide evidence for a partially conserved Cu economy response in rice, in comparison to A. thaliana.

The need to determine mercury in environmental samples is well known, along with its related difficulty. Most methods require samples to be decomposed, involving the use of concentrated acids; this requires considerable time and is liable to lead to analyte loss. The aim of this work is to develop a simple electrothermal vaporization (ETV) system coupled to inductively coupled plasma mass spectrometry (ICP-MS) for Hg determination by direct solid sample analysis (DSSA). The ETV system consists of a high-power lamp enclosed in glass chamber equipped with solenoid valves to control the flow of argon gas (Ar) during pyrolysis and vaporization steps. The system is controlled by a printed circuit board and software developed in the LabVIEW environment. In this system, the analyte vapour was extracted through a glass tube positioned just above the sample, avoiding the analyte deposition on the chamber wall and consequently reducing memory effect. The heating program was optimised and the pyrolysis step was not necessary since it was possible to vaporize the analyte at relatively low temperature (700 °C) without matrix interference. Soil mass between 0.500 and 5.000 mg can be analysed with the ETV system. Calibration was carried out by using a certified reference material (CRM) of soil (NIST2709) ranged from 0.1 to 1.0 ng of Hg. The relative standard deviation was lower than 20% (n = 3) and the limit of quantification (10σ) of Hg was 3.1 ng g−1. The accuracy was evaluated by comparison of results obtained for Hg in CRMs and no statistical differences were observed (paired t-test at a confidence level of 95%). To evaluate the performance of ETV system, soil samples with different concentration levels were analysed and the results were in good agreement (paired t-test at a confidence level of 95%) with those obtained by nebulization-ICP-MS (NEB-ICP-MS) after acid extraction. Therefore, the proposed method can be used for routine analysis, where the time of analysis of approximately 60 s per sample, risk of contamination, analyte losses and generation of residues are drastically reduced in comparison with techniques that require sample extraction for Hg determination by NEB-ICP-MS.

Rare earth elements (REEs) have several applications but the effects on environment are not well known. Therefore, the aim of this work is to establish a method for direct solid sample analysis by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) to evaluate the concentration and distribution of REEs in cultivated and non-cultivated soil. Samples were collected in two areas to 40 cm of depth. The LA-ICP-MS method is easy to be implemented and the sample treatment is very fast comprising only its drying, grounding and pressing as a pellet. The accuracy of the method was evaluated by using a certified reference material (BCR 667 – Estuarine Sediment, Institute for Reference Materials and Measurements (IRMM)) where good agreement with the certified values was obtained. Analyte recovery at two levels of concentration (2.5 and 15.0 μg g−1) was also performed and recoveries in the range of 85%–120% were achieved, values that are acceptable for LA-ICP-MS analysis. In general, the concentration of the REEs is higher in the cultivated soil and increased from the surface to deeper layers, which can be a consequence of fertilizer application.

Zinc (Zn) is a micronutrient, but its excessive concentration can impair plant growth and development. Fertilizers, liming materials, pesticides and fungicides containing Zn have contributed to increase its concentration in agricultural soils. The aim of the present study is to evaluate the effect of Zn excess on the non-enzymatic (anthocyanin and β-ecdysone) and enzymatic (superoxide dismutase-SOD and guaiacol peroxidase-GPX) antioxidant system of two P. glomerata accessions (JB and GD) grown in hydroponic system and soil, under short- and long-term exposure times. Three Zn levels (2, 100 and 200 μM) and two short-term exposure times (7 and 14 d) were tested in the hydroponic experiment. Three Zn levels (2, 100 and 200 mg kg−1) and two long-term exposure times (34 and 74 d) were tested in the soil experiment. The effects of Zn excess on P. glomerata accessions depended on the growth system and exposure time. Zinc excess in both tested growth systems resulted in significant change in the tissue oxidative process (MDA concentration) in both accessions, as well as broadened the antioxidant system response, which was based on antioxidant enzymes (SOD and GPX) and secondary metabolites (anthocyanins and β-ecdysone). The highest anthocyanin concentration was observed in accession JB, which was grown in hydroponics, but tissue anthocyanin concentration increased in both accessions, regardless of growth medium and exposure time. The β-ecdysone concentration in the roots increased in both accessions, but accession GD was more responsive to Zn excess. There was significant physiological variation in P.glomerata accessions in response to Zn excess.