Browsing by Author "Rangel, Maria"
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- Advanced nanofertilizers for iron uptake in calcareous alkaline soilsPublication . Pinho, Simão; Santos, Carla; Rangel, Maria; Vasconcelos, Marta; Reis, Salette; Moniz, Tânia
- Assessment of the impact synthetic Fe(III)-chelates amendment in soil microbial community dynamicsPublication . Machado, Ana; Mesquita, Letícia S.; Rangel, Maria; Mesquita, Raquel B. R.; Rangel, António O. S. S.; Bordalo, Adriano A.
- Assessment of the impact synthetic Fe(III)-chelates amendment in soil microbial community dynamicsPublication . Machado, Ana; Mesquita, Raquel B. R.; Mesquita, Letícia S.; Rangel, Maria; Rangel, António O. S. S.; Bordalo, Adriano A.Background Iron has a crucial role in plant nutrition, being an essential element for plant growth. However, one-third of the Earth soil is iron deficient, resulting in iron deficiency chlorosis (IDC) growth of several crops worldwide, including staple foods. The use of synthetic Fe(III)-chelates is one of the most effective measures to correct IDC in plants, but their environmental impact must be mastered. Therefore, the search for more effective Fe-chelates remains an important issue. Previously [1], a 3,4-HPO Fe-chelate was proposed as a novel-fertilizing agent. Since the increase of nutrients availability in soil is thought to have an impact on the microbial composition, this question needs to be addressed. Therefore, the aim of the study was to investigate the effect of iron complexes of the 3,4-HPO class of ligands on soil bacterial dynamics to better understand their pathways. Method Laboratory scale soil columns (LSSC) were set up, with different soils origin and characteristics (Agricultural, Forestry and Urban), and exposed to two iron-chelates using rain simulations. The structure and abundance of the bacterial community was evaluated by automated ribosomal intergenic spacer analysis (ARISA) and qPCR (rpoB) approaches. Results & Conclusions Cluster analysis of ARISA profiles revealed that the soil characteristics were the major driving selection for the microbial community composition, with the samples from the same soil type clustering together, disregarding the amendment performed. Also, it emerged that the microbial community of forestry and agricultural soils were more similar (46%) than the one present in urban soil, as expected due to the plant influence. Considering each soil type individually, it was possible to observe a clear response to Fe(III) amendment on the microbial assemblage. Additionally, it seems that one of the compounds, the Fe-chelate derived from the ligand Deferiprone, induced greater and/or faster changes, and that the forestry soil was more prone to the microbial shift. These changes can underline a selection for bacteria that can use Fe(III) in its metabolism, or more tolerant to its presence, that needs to be better understood.
- Construction of an Iron (III) selective electrode with a rhodamine-based newly synthesized chelatorPublication . Mesquita, Letícia; Mesquita, Raquel B. R.; Andreia, Leite; Rangel, Maria; Rangel, António O. S. S.
- Determination of iron(III) in water samples by microsequential injection solid phase spectrometry using an hexadentate 3-hydroxy-4-pyridinone chelator as reagentPublication . Miranda, Joana L. A.; Mesquita, Raquel B. R.; Nunes, Ana; Rangel, Maria; Rangel, António O. S. S.In this work, the hexadentate 3,4–hydroxypyridinone ligand was used as reagent for the spectrophotometric quantification of iron(III) in fresh and sea waters, using a micro sequential injection lab-on-valve (μSI-LOV) system in a solid phase spectrometry (SPS) mode. To implement SPS, thus eliminating the sample matrix, a packed column in the flow cell was used; the chosen sorbent was Nitrilotriacetic Acid Superflow resin (NTA). The possibility of performing an analytical curve resorting to just one standard was also demonstrated. The consumption of the hexadentante ligand was about 30 μg per determination and the effluent production lower than 2.5 mL. The dynamic concentration range was 0.45–9.0 μmol L−1, with a limit of detection of 0.13 μmol L−1 and limit of quantification 0.43 μmol L−1. The proposed μSI-LOV-SPS methodology was successfully applied to river, ground, estuarine, tap, and sea waters.
- Development of a sequential injection methodology for iron speciation in waters using an hexadentate 3,4 – hydroxypiridinone chelatorPublication . Miranda, Joana L. A.; Mesquita, Raquel B. R.; Rangel, Maria; Rangel, António O. S. S.
- Effect of tris(3-hydroxy-4-pyridinonate) iron(III) complexes on iron uptake and storage in soybean (Glycine max L.)Publication . Santos, Carla S.; Carvalho, Susana M.P.; Leite, Andreia; Moniz, Tânia; Roriz, Mariana; Rangel, António O. S. S.; Rangel, Maria; Vasconcelos, Marta W.Iron deficiency chlorosis (IDC) is a serious environmental problem affecting the growth of several crops in the world. The application of synthetic Fe(III) chelates is still one of the most common measures to correct IDC and the search for more effective Fe chelates remains an important issue. Herein, we propose a tris(3-hydroxy-4-pyridinonate) iron(III) complex, Fe(mpp)3, as an IDC corrector. Different morphological, biochemical and molecular parameters were assessed as a first step towards understanding its mode of action, compared with that of the commercial fertilizer FeEDDHA. Plants treated with the pyridinone iron(III) complexes were significantly greener and had increased biomass. The total Fe content was measured using ICP-OES and plants treated with pyridinone complexes accumulated about 50% more Fe than those treated with the commercial chelate. In particular, plants supplied with compound Fe(mpp)3 were able to translocate iron from the roots to the shoots and did not elicit the expression of the Fe-stress related genes FRO2 and IRT1. These results suggest that 3,4-HPO iron(III) chelates could be a potential new class of plant fertilizing agents.
- Evaluation of the effect of tris(3-hydroxy-4-pyridinonate) Fe(III) chelates to treat Iron Deficiency ChlorosisPublication . Santos, Carla S.; Ferreira, Sofia; Moniz, Tânia; Leite, Andreia; Vasconcelos, Marta W.; Rangel, MariaIron (Fe) is an essential nutrient for most organisms including plants. However, due to the existence of the element in very insoluble forms in earth crust, the uptake of Fe by plants is seriously compromised in alkaline soils, which correspond to 30% of the world’s arable land. As a consequence, plants suffer from Fe deficiency chlorosis (IDC), characterized by chlorosis, yield losses, and lower concentrations of Fe in edible plant parts. Farmers rely on supplementing their crops with Fe-chelates to avoid serious growth deficiencies and Fe-EDTA and Fe-EDDHA are the available commercial products. The limited number of distinct Fe chelates that are used as fertilizers calls for the identification of new ligands capable of producing Fe-complexes with properties that allow more efficient pathways for root uptake, root to shoot translocation and maintenance of metal homeostasis. Herein we report studies regarding the capacity of two tris(3-hydroxy-4-pyridinonate) Fe(III) complexes [Fe(mpp)3] and [Fe(dmpp)3] to amend IDC in hydroponically grown soybean (Glycine max) plants. The application of all complexes improved plants condition when compared to those grown with no added Fe treatment. Moreover, plants treated with [Fe(mpp)3] exhibited the best overall results. Plants presented: (a) higher relative chlorophyll content; (b) higher biomass development and (c) higher Fe accumulation. Plants treated with the compound [Fe(mpp)3] were able to translocate more iron from the roots to the shoots not eliciting the expression of the Fe stress related genes. The results suggest that 3,4-HPO Fe-chelates could be economically and environmentally favourable in agricultural contexts
- Exploiting the lab-on-valve concept to study the 3,4-HPO chelator as non-toxc reagent for the determination of iron in costal and inland bathing watersPublication . Mesquita, Raquel; Suarez, Ruth; Rangel, Maria; Bordalo, Adriano A.; Cerdà, Víctor; Rangel, António O. S. S.
- Exploiting the use of 3,4-HP Oligands as non toxic reagents for the determination of iron in natural waters with a sequential injection approachPublication . Mesquita, Raquel B. R.; Suárez, Ruth; Cerdà, Víctor; Rangel, Maria; Rangel, António O.S.S.In this paper, the use of 3-hydroxy-4-pyridinone (3,4-HPO) chelators as nontoxic chromogenic reagents for iron determination is proposed. The potential application of these compounds was studied in a sequential injection system. The 3,4-HPO ligands used in this work were specially designed to complex iron(III) at physiologic pH for clinical applications. The developed sequential injection method enabled to study the reaction conditions, such as buffering and interferences. Then, to further improve the low consumption levels, a microsequential injection method was developed and effectively applied to iron determination in bathing waters using 3,4-HPO ligands. The formed iron complex has a maximum absorbance at 460 nm. The advantage of using minimal consumption values associated with sequential injection, together with the lack of toxicity of 3,4-HPO ligands, enabled to present a greener chemistry approach for iron determination in environmental samples within the range 0.10-2.00 mg Fe/L with a LOD of 7 mu g/L. The overall effluent production was 350 mu L corresponding to the consumption of 0.48 mg of 3,4-HPO ligand, 0.11 mg of NaHCO3, 0.16 mg of HNO3 and 50 mu L. of sample. Three reference samples were assessed for accuracy studies and a relative deviation < 5% was obtained. The results obtained for the assessment of iron in inland bathing waters were statistically comparable to those obtained by the reference procedure.