Publications by authors named "Aristéa Alves Azevedo"

12 Publications

  • Page 1 of 1

Anatomy, Flow Cytometry, and X-Ray Tomography Reveal Tissue Organization and Ploidy Distribution in Long-Term Cultures of Species.

Front Plant Sci 2020 31;11:1314. Epub 2020 Aug 31.

Laboratory of Plant Tissue Culture II-BIOAGRO, Plant Biology Department, Federal University of Viçosa (UFV), Viçosa, Brazil.

Cacti have a highly specialized stem that enables survival during extended dry periods. Despite the ornamental value of cacti and the fact that stems represent the main source of explants in tissue culture, there are no studies on their morpho-anatomical and cytological characteristics in . The present study seeks to address the occurrence of cells with mixed ploidy level in cacti tissues. Specifically, we aim to understand how stem tissue is organized, how mixoploidy is distributed when present, and whether detected patterns of ploidy change after long periods of culture. To analyze tissue organization, and plants that had been germinated and cultivated were analyzed for stem structure using toluidine blue, Xylidine Ponceau, Periodic Acid Schiff, ruthenium red, and acid floroglucin. To investigate patterns of ploidy, apical, medial, and basal zones of the stem, as well as, periphery, cortex, and stele (vascular tissue and pith) regions of the stem and root apexes from four- and ten-year old cultured were analyzed by flow cytometry. X-ray micro-computed tomography (XRµCT) was performed with fragments of stems from both species. The scarcity of support elements (, sclereids and fibers) indicates that epidermis, hypodermis, and wide-band tracheids present in cortical vascular bundles and stele, as well as water stored in aquifer parenchyma cells along the cortex, provide mechanical support to the stem. Parenchyma cells increase in volume with a four-fold increase in ploidy. and exhibit the same pattern of cell ploidy irrespective of topophysical region or age, but there is a marked difference in ploidy between the stem periphery (epidermis and hypodermis), cortex, stele, and roots. Mixoploidy in is not related to the age of the culture, but is a developmental trait, whereby endocycles promote cell differentiation to accumulate valuable water.
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http://dx.doi.org/10.3389/fpls.2020.01314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7488924PMC
August 2020

Rare earth elements induce cytoskeleton-dependent and PI4P-associated rearrangement of SYT1/SYT5 endoplasmic reticulum-plasma membrane contact site complexes in Arabidopsis.

J Exp Bot 2020 07;71(14):3986-3998

Department of Botany, University of British Columbia, Vancouver, Canada.

In plant cells, environmental stressors promote changes in connectivity between the cortical endoplasmic reticulum (ER) and the plasma membrane (PM). Although this process is tightly regulated in space and time, the molecular signals and structural components mediating these changes in interorganelle communication are only starting to be characterized. In this report, we confirm the presence of a putative tethering complex containing the synaptotagmins 1 and 5 (SYT1 and SYT5) and the Ca2+- and lipid-binding protein 1 (CLB1/SYT7). This complex is enriched at ER-PM contact sites (EPCSs), has slow responses to changes in extracellular Ca2+, and displays severe cytoskeleton-dependent rearrangements in response to the trivalent lanthanum (La3+) and gadolinium (Gd3+) rare earth elements (REEs). Although REEs are generally used as non-selective cation channel blockers at the PM, here we show that the slow internalization of REEs into the cytosol underlies the activation of the Ca2+/calmodulin intracellular signaling, the accumulation of phosphatidylinositol-4-phosphate (PI4P) at the PM, and the cytoskeleton-dependent rearrangement of the SYT1/SYT5 EPCS complexes. We propose that the observed EPCS rearrangements act as a slow adaptive response to sustained stress conditions, and that this process involves the accumulation of stress-specific phosphoinositide species at the PM.
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http://dx.doi.org/10.1093/jxb/eraa138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7337092PMC
July 2020

Calycinal secretory structures in Calolisianthus pedunculatus (Cham. & Schltdl) Gilg (Gentianaceae): anatomy, histochemistry, and functional aspects.

Protoplasma 2020 Jan 9;257(1):275-284. Epub 2019 Sep 9.

Programa de Pós-Graduação em Botânica, Departamento de Biologia Vegetal, Universidade Federal de Viçosa (UFV), Av. P.H. Rolfs, s/n, Campus Universitário, Viçosa, MG, 36570-900, Brazil.

Secretory structures were little studied in Gentianaceae. Glandular areas on the calyx dorsal region are commonly reported for Helieae species, the main tribe of Gentianaceae. So, the elucidation of nature of glandular areas is particularly relevant. Trichomes secreting mucilage, interpreted as colleters, are reported only for the sepals of Gentianinae species. We aimed to anatomically characterize and identify the nature of the calycinal secretory structures in Calolisianthus pedunculatus. Samples from floral buds, flowers, and fruits were collected, fixed, and processed following usual procedures for light and scanning electron microscopies. Histochemical tests were performed to determine the nature of the secretion. Glucose, fructose, and sucrose were measured with an ELISA reader. Colleters occur on the sepal ventral region and are composed of a multicellular secretory head and a stalk. These structures secrete polysaccharides and proteins, and the secretion is probably released through cuticle microchannels. Nectaries, on the other hand, occur on the sepal dorsal region. They are formed by 3-5 cells arranged in rosettes circling a central cell or pore. These structures also secrete polysaccharides (mainly fructose), lipids, and proteins. The identification of the secretory structures in the sepals of Calolisianthus pedunculatus highlights the importance of anatomical studies in this family. The interpretation of the glandular areas on the calyx of the Helieae species as nectaries has been proven, as well as the confirmation of colleters as common structures in the sepals of Gentianaceae. Besides the taxonomic and phylogenetic importance of nectars and colleters, we highlight the importance of the secretion for the protection of floral buds against dehydration.
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http://dx.doi.org/10.1007/s00709-019-01436-5DOI Listing
January 2020

Arsenic hyperaccumulation in Pityrogramma calomelanos L. (Link): adaptive traits to deal with high metalloid concentrations.

Environ Sci Pollut Res Int 2018 Apr 2;25(11):10720-10729. Epub 2018 Feb 2.

Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs, s/n, Viçosa, MG, 36570-900, Brazil.

Pityrogramma calomelanos is interestingly the single non-Pteris arsenic (As)-hyperaccumulating fern. It has been pointed as a potential species for phytoremediation and a model plant to study the As toxicity and its mechanisms of action. In order to investigate the morphoanatomical traits associated to As tolerance, P. calomelanos plants were exposed to different As concentrations in hydroponic solution. At low As dose (1 mM As), 90% of the As accumulated in plants was allocated in shoots, and no symptoms of As stress were observed in fronds and roots. Under higher As exposure (10 and 30 mM As), 81-74% of the total As in plants was present in shoots, and apical and marginal necroses on pinnae were observed. Anatomical observations showed that As induces damages mainly in the secondary veins and adjacent cells. High amounts of phenols were observed in pinna tissues of control and treated plants. In the roots, As promoted slight alterations as detachment of border-like cells and accumulation of granular substances in cortical cells. The high root-to-shoot As translocation and the constitutive presence of phenols and border-like cells protecting the root tips showed to be adaptive traits that allow P. calomelanos to survive in contaminated sites.
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http://dx.doi.org/10.1007/s11356-017-1085-9DOI Listing
April 2018

Clusia hilariana and Eugenia uniflora as bioindicators of atmospheric pollutants emitted by an iron pelletizing factory in Brazil.

Environ Sci Pollut Res Int 2017 Dec 9;24(36):28026-28035. Epub 2017 Oct 9.

Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brasil.

The objectives of this work were to evaluate if the pollution emitted by the pelletizing factory causes visual symptoms and/or anatomical changes in exposed Eugenia uniflora and Clusia hilariana, in active biomonitoring, at different distances from a pelletizing factory. We characterize the symptomatology, anatomical, and histochemistry alterations induced in the two species. There was no difference in the symptomatology in relation to the different distances of the emitting source. The foliar symptoms found in C. hilariana were chlorosis, necrosis, and foliar abscission and, in E. uniflora, were observed necrosis punctuais, purple spots in the leaves, and increase in the emission of new leaves completely purplish. The two species presented formation of a cicatrization tissue. E. uniflora presented reduction in the thickness of leaf. In C. hilariana, it was visualized hyperplasia of the cells and the adaxial epidermis did not appear collapsed due to thick cuticle and cuticular flanges. Leaves of C. hilariana showed positive staining for iron, protein, starch, and phenolic compounds. E. uniflora showed positive staining for total phenolic compounds and starch. Micromorphologically, there was accumulation of particulate matter on the leaf surface, obstruction of the stomata, and scaling of the epicuticular wax in both species. It was concluded that the visual and anatomical symptoms were efficient in the diagnosis of the stress factor. C. hilariana and E. uniflora showed to be good bioindicators of the atmospheric pollutants emitted by the pelletizing factory.
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http://dx.doi.org/10.1007/s11356-017-0386-3DOI Listing
December 2017

Differential responses of C3 and CAM native Brazilian plant species to a SO2- and SPMFe-contaminated Restinga.

Environ Sci Pollut Res Int 2015 Sep 9;22(18):14007-17. Epub 2015 May 9.

Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, Viçosa, MG, 36570-900, Brazil,

Aiming to evaluate responses in terms of growth rates, physiological parameters, and degree of sensitivity to SO2 and SPMFe in Eugenia uniflora L. (Myrtaceae, a C3 species) and Clusia hilariana Schlecht (Clusiaceae, a CAM species); saplings were exposed to emissions from a pelletizing factory for 7 months. The species were distributed along a transect (200, 500, 800, 1400, and 1700 m away from the emission source), and analyses were performed after 71, 118, and 211 days of exposure to the pollutants. E. uniflora received higher superficial deposition of particulate iron. The highest total iron foliar contents were observed 200 m away from the emission source in both plant species, while the highest total sulfur foliar contents were observed 200 m away in C. hilariana and 800 m away in E. uniflora. E. uniflora presented decreased values of height growth rate, number of necrotic leaves, chlorophyll analysis (SPAD index) and transpiration, in relation to the distances from the emission source. C. hilariana showed decreased values of height growth rate, number of leaves, number of necrotic leaves, total ionic permeability, stomatal conductance, transpiration, net CO2 assimilation, and total dry matter, in relation to distances from the emission source. In relation to the days of exposure, both species presented increased number of necrotic leaves and foliar phytotoxicity index, and decreased values in the chlorophyll analysis. The two native plant species, both of which occur in the Brazilian Restinga, showed damage when exposed to emissions from an iron ore pelletizing factory. C. hilariana was considered the most sensitive species due to the decreased values in a higher number of variables after exposition.
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http://dx.doi.org/10.1007/s11356-015-4391-0DOI Listing
September 2015

Morpho-anatomical and growth alterations induced by arsenic in Cajanus cajan (L.) DC (Fabaceae).

Environ Sci Pollut Res Int 2015 Aug 24;22(15):11265-74. Epub 2015 Mar 24.

Department of Plant Biology, Federal University of Viçosa, Viçosa, MG, 36570-000, Brazil.

Arsenic (As) is a toxic element to most organisms. Studies investigating anatomic alterations due to As exposure in plants are scarce but of utmost importance to the establishment of environmental biomonitoring techniques. So, this study aimed to investigate the effects of As on the development and initial root growth in Cajanus cajan (Fabaceae), characterize and quantify the possible damages, evaluate genotoxic effects, and identify structural markers to be used in environmental bioindication. Plants were exposed hydroponically to 0.5, 1.0, 1.5, and 2.0 mg As L(-1), as sodium arsenate. Growth parameters were measured, and in the end of the exposure, root samples were analyzed for qualitative and quantitative anatomical alterations. Arsenic genotoxicity was evaluated through analysis of the mitotic index in the root apex. Compared to the control, As-treated seedlings showed an altered architecture, with significantly decreased root length (due to the lower mitotic index in the apical meristem and reduced elongation of parenchyma cells) with darkened color, and abnormal development of the root cap. A significant increase in vascular cylinder/root diameter ratio was also detected, due to the reduction of the cellular spaces in the cortex. The secondary xylem vessel elements were reduced in diameter and had sinuous walls. The severest damage was visible in the ramification zone, where uncommon division planes of phellogen and cambium cells and disintegration of the parenchyma cells adjacent to lateral roots were observed. The high sensibility of C. cajan to As was confirmed, since it caused severe damages in root growth and anatomy. The main structural markers for As toxicity were the altered root architecture, with the reduction of the elongation zone and increase of ramification zone length, and the root primordia retained within the cortex. Our results show a new approach about As toxicity and indicate that C. cajan is a promising species to be used for bioindication of environmental contamination by As.
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http://dx.doi.org/10.1007/s11356-015-4342-9DOI Listing
August 2015

Morphoanatomical responses induced by excess iron in roots of two tolerant grass species.

Environ Sci Pollut Res Int 2015 Feb 31;22(3):2187-95. Epub 2014 Aug 31.

Universidade Federal de Viçosa, 36570-900, Viçosa, MG, Brazil.

We aimed to verify whether morphoanatomic alterations occur in response to excess iron, in roots of Setaria parviflora and Paspallum urvillei (Poaceae), and to localize the presence of the sites of iron accumulation. Plants were subjected to 0.009, 1, 2, 4, and 7 mM Fe-EDTA in nutrient solution. Both species presented iron contents in the roots above the critical toxicity level. The presence of iron plaque on roots of the two species was confirmed, and it may have reduced iron absorption by the plants. Roots from the two species showed typical visual symptoms of stress by excess iron: change in color and mucilaginous and flaccid appearance. Anatomical damage was observed in both species: aerenchyma disruption, alterations in endodermal cells, and irregular shape of both vessel and sieve tube elements. The metal was histolocalized in the cortex and in protoxylem and metaxylem cell walls in both species, which suggests a detoxification strategy for the excess iron. Phenolic compounds were not histolocalized in roots. Microscopic analyses were therefore effective in evaluating the real damage caused by excess iron.
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http://dx.doi.org/10.1007/s11356-014-3488-1DOI Listing
February 2015

Leaf morphoanatomy of species tolerant to excess iron and evaluation of their phytoextraction potential.

Environ Sci Pollut Res Int 2014 Feb 3;21(4):2550-62. Epub 2013 Oct 3.

Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.

Setaria parviflora (Poir.) Kerguélen and Paspalum urvillei Steudel are grasses that grow naturally in a soil with high iron contents. This study aimed to characterize morphoanatomically and histochemically the iron phytotoxicity on leaves and evaluate the phytoextraction potential of these grasses. Saplings were cultivated in hydroponic solution with and without excess Fe-EDTA. Regarding measurements taken on leaves, reduction was observed among treatments of Fe-EDTA on height values of abaxial epidermis and bundle sheath in both species. As for iron histolocalization, stronger reaction was observed in leaves of S. parviflora, in comparison with P. urvillei. Anatomical damage, such as protoplast retraction, irregular xylem, changes in cell volume, and cell collapse, and visual symptoms, like leaf bronzing, chlorosis, and necrosis, were similar in both species when exposed to excess iron; however, P. urvillei showed more severe damage. This species accumulated more iron in shoots than S. parviflora and therefore is more favorable for use in phytoextraction. The root system of both species accumulated higher iron concentrations in relation to shoots.
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http://dx.doi.org/10.1007/s11356-013-2160-5DOI Listing
February 2014

Tolerance to iron accumulation and its effects on mineral composition and growth of two grass species.

Environ Sci Pollut Res Int 2014 Feb 17;21(4):2777-84. Epub 2013 Oct 17.

Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, Minas Gerais, Brazil.

This study aimed to assess the influence of excess iron on the capacity of accumulation of this heavy metal, mineral composition, and growth of Setaria parviflora and Paspalum urvillei. Seedlings were submitted to 0.009; 1; 2; 4; and 7 mM of Fe-EDTA. In both species there was an increase in the concentration of Fe, Zn, P, and Ca and a decrease in Mn, K, and Mg in the iron plaque. Both species accumulated more iron in roots. In the shoots, S. parviflora showed higher iron content, except at 7 mM. Iron altered the contents of Fe, Cu, K, and Mg in roots, and of Fe, Mn, Zn, N, P, K, Ca, and Mg in shoots. The two species tolerated high iron concentrations and accumulated high content of this element in both shoots and roots. The iron did not reduce their growth. Both species are indicated for studies aiming restoration of iron-contaminated areas.
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http://dx.doi.org/10.1007/s11356-013-2201-0DOI Listing
February 2014

Extrafloral nectaries in neotropical Gentianaceae: occurrence, distribution patterns, and anatomical characterization.

Am J Bot 2013 Sep 5;100(9):1779-89. Epub 2013 Sep 5.

Departamento de Biologia Vegetal, Universidade Federal de Viçosa (UFV), Av. P.H. Rolfs, s/n, Campus Universitário, CEP 36570-000, Viçosa, Minas Gerais, Brasil.

Unlabelled:

Premise Of The Study: Extrafloral nectaries (EFNs) are structures that secrete nectar and protect plants against herbivores and pathogens. In Gentianaceae, these structures have been described in species of Calolisianthus, Fagraea, and Anthocleista and are important morphological markers for taxonomic and phylogenetic studies. To establish a foundation for further studies, we investigated the occurrence, distribution patterns, and anatomy of EFNs on leaves of 27 species belonging to 13 genera and three tribes of neotropical Gentianaceae. •

Methods: Leaf samples were diaphanized, stained with basic fuchsin, and mounted in glycerinated gelatin. Cross sections were obtained from material embedded in methacrylate or paraffin, stained, and mounted in Permount. Polysaccharides were histochemically stained with periodic acid-Schiff stain. Samples were also examined with scanning electron microscopy. •

Key Results: Unusual EFNs, visible only with light microscopy, were formed of modified epidermal cells. Each EFN consisted of 2-5 secretory cells encircling a central cell. The EFNs varied in size and in the shape and arrangement of the adjacent cells surrounding the secretory cells. EFNs occurred in all analyzed species as isolated units distributed throughout the leaf blade or as aggregates; aggregates were generally visible to the naked eye. Based on their occurrence as aggregates or isolated units and on their location on the leaf blade, six distribution patterns were identified. •

Conclusions: This is the first comprehensive study of EFNs on the leaves of neotropical Gentianaceae. The data suggested that NEFs evolved from isolated units for NEFs in aggregates. The results represent a new source of data for future ecological, systematic, and phylogenetic studies in Gentianaceae.
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http://dx.doi.org/10.3732/ajb.1300130DOI Listing
September 2013

Iron plaque formation and morphoanatomy of roots from species of restinga subjected to excess iron.

Ecotoxicol Environ Saf 2012 Apr 9;78:265-75. Epub 2011 Dec 9.

Departamento de Biologia Vegetal, Universidade Federal de Viçosa. PH Rolfs, s/n, Campus Universitário, Viçosa, Minas Gerais 36.570-000, Brazil.

The restingas, a sandy coastal plain ecosystem of Brazil, have received an additional amount of iron due to the activity of mining industries. The present study aims to characterize morphoanatomically and histochemically the iron plaque formation on roots of Ipomoea pes-caprae L. and Canavalia rosea DC, cultivated in hydroponic solution with and without excess iron. The iron plaque formation as well as changes in the external morphology of the lateral roots of both species were observed after the subjection to excess iron. Changes in the nutrient uptake, and in the organization and form of the pericycle and cortex cells were observed for both species. Scanning electron microscopy showed evident iron plaques on the whole surface of the root. The iron was histolocalized in all root tissues of both species. The species of restinga studied here formed iron plaque in their roots when exposed to excess of this element, which may compromise their development in environments polluted by particulated iron.
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http://dx.doi.org/10.1016/j.ecoenv.2011.11.030DOI Listing
April 2012
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