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1.
Funct Plant Biol ; 512024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38163648

RESUMO

Environments originating from banded iron formations, such as the canga , are important reference ecosystems for the recovery of degraded areas by mining. The objective of this work was to evaluate if the relationship between morphofunctional and photosynthetic attributes of native canga species from different functional group results in distinct responses when grown in iron mining tailings substrate. The experiment was carried out with species belonging to different functional groups: a widespread semi-deciduous tree-shrub, Myrcia splendens ; an endemic deciduous shrub, Jacaranda caroba ; and a nitrogen-fixing herbaceous species, Periandra mediterranea . The species were grown in two conditions, reference soil and iron ore tailing. Despite belonging to different functional groups when grown in tailings, the morphofunctional attributes presented similar responses between species. M. splendens was the species most affected by the conditions imposed by the iron ore mining tailings, with decreased light-use efficiency and electron transport. P. mediterranea had satisfactory growth and maintenance of photosynthetic attributes. J. caroba growing in the tailings increased the effective quantum yield of PSII. The photochemical and growth assessments were able to better explain the adaptive strategies developed by the species, guaranteeing a greater chance of success during the rehabilitation of mining substrates.


Assuntos
Ecossistema , Ferro , Plantas/metabolismo , Árvores/metabolismo , Mineração
2.
Environ Sci Pollut Res Int ; 30(2): 3760-3773, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35948796

RESUMO

The iron ore tailings released into the Rio Doce basin after the Fundão dam collapse (Brazil), suppressed a large extent of local vegetation. The use of native species and appropriate fertilization techniques, with less economic and environmental impact, must be considered in the process for the restoration of affected areas by the tailings. For this purpose, six native tree species, pioneer (Anadenanthera colubrina, Bixa orellana, and Peltophorum dubium) and secondary (Cedrela fissilis, Handroanthus impetiginosus, and Handroanthus serratifolius), were selected. We used different conditions of fertilization: (1) inorganic fertilization, (2) inoculation with arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria, (3) combined treatment (fertilizer + inoculum), to evaluate leaf nutrient concentrations, photosynthetic capacity [chlorophyll index, maximum quantum efficiency of photosystem II (Fv/Fm) and gas exchange variables], and oxidative metabolism (H2O2, MDA, and antioxidant enzymes). Inoculation resulted in higher concentrations of foliar nitrogen, especially in pioneer species. In all treatments, the secondary species exhibited iron values considered phytotoxic, but showed reduced photosynthetic capacity only when inoculated. The highest concentrations of MDA were observed in inoculated plants of both successional groups. The antioxidant system proved to be effective in preventing oxidative damage for most of the species. These results showed that the use of inoculum can be considered an ecological alternative to inorganic additives in the area affected by iron ore tailings. Despite presenting different photosynthetic and antioxidant strategies, the evaluated species demonstrated potential for use in tailings revegetation projects.


Assuntos
Compostos de Ferro , Árvores , Árvores/metabolismo , Antioxidantes , Peróxido de Hidrogênio , Ferro/metabolismo , Fertilização
3.
Ecology ; 104(1): e3852, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36053857

RESUMO

Advancing functional ecology depends fundamentally on the availability of data on reproductive traits, including those from tropical plants, which have been historically underrepresented in global trait databases. Although some valuable databases have been created recently, they are mainly restricted to temperate areas and vegetative traits such as leaf and wood traits. Here, we present Rock n' Seeds, a database of seed functional traits and germination experiments from Brazilian rock outcrop vegetation, recognized as outstanding centers of diversity and endemism. Data were compiled through a systematic literature search, resulting in 103 publications from which seed functional traits were extracted. The database includes information on 16 functional traits for 383 taxa from 148 genera, 50 families, and 25 orders. These 16 traits include two dispersal, six production, four morphological, two biophysical, and two germination traits-the major axes of the seed ecological spectrum. The database also provides raw data for 48 germination experiments, for a total of 10,187 records for 281 taxa. Germination experiments in the database assessed the effect of a wide range of abiotic and biotic factors on germination and different dormancy-breaking treatments. Notably, 8255 of these records include daily germination counts. This input will facilitate synthesizing germination data and using this database for a myriad of ecological questions. Given the variety of seed traits and the extensive germination information made available by this database, we expect it to be a valuable resource advancing comparative functional ecology and guiding seed-based restoration and biodiversity conservation in tropical megadiverse ecosystems. There are no copyright restrictions on the data; please cite this paper when using the current data in publications; also the authors would appreciate notification of how the data are used in publications.


O avanço da ecologia funcional depende fundamentalmente da disponibilidade de dados sobre traços reprodutivos, incluindo dados de plantas tropicais, que têm sido historicamente subrepresentados em bancos de dados de traços funcionais globais. Embora alguns bancos de dados valiosos tenham sido criados recentemente, eles são restritos principalmente a áreas temperadas e a traços vegetativos, como traços de folhas e madeira. Neste artigo apresentamos Rock n' Seeds, um banco de dados de traços funcionais de sementes e experimentos de germinação de vegetações associadas a afloramentos rochosos do Brasil, os quais são reconhecidos como centros notáveis de diversidade e endemismo. Os dados foram compilados através de uma revisão sistemática na literatura, resultando em 103 publicações das quais foram extraídos os traços funcionais das sementes. O banco de dados inclui informações de 16 traços funcionais para 383 taxa de 148 gêneros, 50 famílias e 25 ordens. Estes dezesseis traços incluem dois traços de dispersão, seis de produção, quatro morfológicos, dois biofísicos e dois germinativos; os eixos principais do espectro ecológico da semente. O banco de dados também fornece os dados brutos para 48 experimentos de germinação para um total de 10.187 registros para 281 taxa. Os experimentos de germinação no banco de dados avaliaram o efeito de uma ampla gama de fatores abióticos e bióticos sobre a germinação e diferentes tratamentos de quebra de dormência. Particularmente, 8.255 desses registros incluem a contagem diária da germinação. Estas informações facilitarão a síntese de dados de germinação e a utilização deste banco de dados para uma grande variedade de questões ecológicas. Dada a variedade de traços das sementes e as amplas informações sobre germinação disponibilizadas por este banco de dados, esperamos que ele seja um recurso valioso para o avanço da ecologia funcional comparativa e para orientar a restauração baseada em sementes e a conservação da biodiversidade em ecossistemas tropicais megadiversos. Não há restrições de direitos autorais sobre os dados; favor citar este artigo ao utilizar os dados nas publicações e os autores agradeceriam uma notificação de como os dados são utilizados nas publicações.


El avance de la ecología funcional depende fundamentalmente de la disponibilidad de datos sobre rasgos reproductivos-incluyendo los de las plantas tropicales-los cuales han estado poco representados en las bases de datos globales de rasgos. Aunque recientemente se han creado algunas bases de datos valiosas, estas se encuentran restringidas principalmente a las zonas templadas y a los rasgos vegetativos, como los de las hojas y la madera. En este artículo presentamos Rock n' Seeds, una base de datos de rasgos funcionales de semillas y experimentos de germinación de la vegetación asociada a afloramientos rocosos de Brasil, los cuales son destacados centros de diversidad y endemismo. Los datos se recopilaron mediante una búsqueda bibliográfica sistemática, que dio como resultado 103 publicaciones de las que se extrajeron los rasgos funcionales de las semillas. La base de datos incluye información de dieciséis rasgos funcionales para 383 taxones de 148 géneros, 50 familias y 25 órdenes. Estos rasgos incluyen dos rasgos de dispersión, seis de producción, cuatro morfológicos, dos biofísicos y dos de germinación; siendo estos los principales ejes del espectro ecológico de las semillas. La base de datos también proporciona los datos brutos de 48 experimentos de germinación, para un total de 10.187 registros de 281 taxones. Dichos experimentos de germinación evaluaron el efecto de una amplia gama de factores abióticos y bióticos sobre la germinación y de diferentes tratamientos para romper la dormancia. En particular, 8.255 de estos registros cuentan con conteos diarios de germinación. Esto facilitará la síntesis de los datos de germinación y el uso de esta base de datos para una gran diversidad de preguntas ecológicas. Dada la variedad de rasgos de las semillas y la amplia información sobre germinación que ofrece esta base de datos, esperamos que sea un recurso valioso para el avance de la ecología funcional comparativa y para orientar la restauración basada en semillas y la conservación de la biodiversidad en ecosistemas tropicales megadiversos. No hay restricciones de derechos de autor sobre los datos; se solicita citar este documento cuando se utilicen los datos en publicaciones y los autores agradecerán ser notificados sobre cómo se utilizan los datos en las publicaciones.


Assuntos
Ecossistema , Germinação , Humanos , Brasil , Sementes , Plantas
4.
Environ Monit Assess ; 194(6): 410, 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35532857

RESUMO

A great amount of iron ore tailings from the collapse of the Fundão dam in Southeast Brazil was deposited in an extensive agricultural area. The presence of this material creates insecurity for the resumption of agricultural activities, especially the cultivation of vegetables, which can accumulate metals at potentially toxic levels. In this study, two vegetables consumed in the affected area, arugula and radish, were cultivated in tailings and in soil. Productivity, photosynthetic pigment content, photosynthetic performance, metal accumulation, and the possible risk to food safety were analyzed. The productivity of both vegetables, arugula and radish, did not differ between cultivation in tailings and in soil. There were no differences in pigment content nor substantial differences in the photosynthetic parameters of plants grown in the two substrates. Plants grown in tailings had higher Fe, Mn, and Na contents than those grown in soil, reflecting the higher levels of these elements in the former. There were no visual signs of metal toxicity for plants grown in the tailings. The levels of metals potentially ingested through estimated consumption of arugula and radish grown in the tailings were below the maximum allowable limits for human consumption. In addition, calculated risk indices suggest a low potential for harm to the health of consumers of cultivated vegetables in the tailings. The results presented here suggest that agricultural cultivation in the tailings is viable and contribute to the resumption of vegetable cultivation in the region affected by the tailings released with the collapse of the Fundão dam.


Assuntos
Metais Pesados , Poluentes do Solo , Colapso Estrutural , Brasil , Monitoramento Ambiental , Inocuidade dos Alimentos , Humanos , Metais , Metais Pesados/análise , Plantas , Solo , Poluentes do Solo/análise , Verduras
5.
Environ Sci Pollut Res Int ; 29(12): 18047-18062, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34686954

RESUMO

The rupture of Fundão dam was the biggest environmental disaster of the worlds' mining industry, dumping tons of iron ore tailings into the environment. Studies have shown that the Fundão dam's tailings are poor in nutrients and have high Fe and Mn concentration. In this context, our objective was to evaluate the growth performance of two native tree species (Bowdichia virgilioides and Dictyoloma vandellianum) in two treatments: fertilized soil and fertilized tailings. We hypothesize that the high concentrations of iron and manganese in the tailings can impair the growth performance of plants by interfering with the absorption of nutrients made available through fertilization. Soil and tailings samples were collected in the municipality of Barra Longa (MG, Brazil), and then fertilized with mixed mineral fertilizer ("Osmocote Plus 15-9-12" at 7.5 g L-1). The experiment was conducted for 75 days in a greenhouse using 180 cm3 tubes. We evaluate chlorophyll content, maximal PSII quantum yield, root length, shoot length, root:shoot ratio, leaf area, specific leaf area and leaf area ratio, dry mass, macro- and micronutrients concentration in the tissues, and metal translocation factor. Although assuring the adequate levels of the main nutrients to plant growth (N, P, K, Ca, and Mg), the fertilization did not reverse the negative effect of tailing on these species. The high concentration of Fe in the tissues associated with less biomass production, lower plant height, smaller leaf area, bigger specific leaf area, and reduced chlorophyll content indicates a probable phytotoxic effect of iron present in the tailings for D. vandellianum. Our results base further field evaluations and longer experiments, which will facilitate the understanding of the performance of tree species submitted to tailings with fertilization. So far, this study suggests that B. virgilioides are more tolerant to excess Fe from the tailings of Fundão dam than D. vandellianum.


Assuntos
Poluentes do Solo , Brasil , Fertilização , Ferro , Minerais , Solo , Poluentes do Solo/análise
6.
Physiol Plant ; 174(1): e13595, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34766358

RESUMO

Increasing global temperatures could result in decreasing crop production by decreasing seed germination in the field due to thermodormancy acquisition. Certain metals appear to modulate seed thermodormancy, although the exact mechanisms of that effect have not yet been elucidated. We report here the effects of Zn on the thermodormancy of sorghum seeds. Seeds treated with 0 or 200 mg Zn L-1 were germinated at optimal (30°C) and supra-optimal (40°C) temperatures and their germinability and oxidative stress markers were evaluated. The integrative effects of Zn, abscisic acid (ABA), gibberellin (GA), and H2 O2 on the physiology of seed thermodormancy were examined. The supra-optimal germination temperature (40°C) induced seed thermodormancy, which was, however, alleviated by treatment with 200 mg Zn L-1 . Thermodormancy acquired at supra-optimal temperatures in sorghum seeds must reflect de novo synthesis and accumulation of ABA. Although Zn treatment did not prevent ABA accumulation, it increased the activities of mitochondrial ETC enzymes and decreased the antioxidant enzymes' activity, leading to the accumulation of H2 O2 . By increasing mitochondria activity and H2 O2 production, Zn may induce GA synthesis and alleviate thermodormancy in sorghum seeds. The pretreatment of sorghum seeds with Zn may therefore improve seed germination and assure increased crop performance under normal (30°C) or rising (up to 40°C) temperatures.


Assuntos
Giberelinas , Sorghum , Ácido Abscísico/farmacologia , Germinação , Giberelinas/farmacologia , Peróxido de Hidrogênio/farmacologia , Sementes/fisiologia , Zinco/farmacologia
7.
Ecotoxicol Environ Saf ; 189: 110021, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31830604

RESUMO

The failure of the Fundão dam, the largest environmental disaster in the world's mining sector, was responsible for releasing millions of cubic meters of iron ore tailings into the environment. It affected thousands of hectares of the Atlantic Forest domain, one of the biodiversity hotspots for conservation. Considering the urgency to restore the flora of the affected area, we evaluated the effects that iron ore tailings from the Fundão reservoir have on the germination and initial growth of tree species native to the Atlantic Forest in the Rio Doce basin. We demonstrated that the tailings do not affect the seed germination, but do negatively interfere with plant growth. Lower biomass production, height, leaf area, chlorophyll concentration and photosynthesis as well as high concentration of iron was observed in plants grown in the tailings. Thus, we investigated if these deleterious effects were due to the presence of potentially toxic metals or nutritional deficiency imposed by low fertility of the tailings. We concluded that reduced growth was a result of nutritional limitations due to low nutrient availability, low organic matter content and low cation exchange capacity of the tailings. This conclusion was further supported by the application of fertilization, which reversed the deleterious effect of the waste on the growth of plants, assuring physiological levels of iron and nutrients in the shoot. Thus, this strategy should be considered for in situ recovery projects aiming to improve the performance of native plants.


Assuntos
Solo/química , Árvores/crescimento & desenvolvimento , Biomassa , Recuperação e Remediação Ambiental , Fertilização , Ferro/análise , Ferro/metabolismo , Mineração , Nutrientes/análise , Nutrientes/deficiência , Nutrientes/metabolismo , Floresta Úmida , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Árvores/classificação , Árvores/metabolismo
8.
Chemosphere ; 233: 905-912, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340418

RESUMO

We investigated the interconnected roles of reactive oxygen species (ROS) generated upon seed exposure to glyphosate and/or gibberellic acid (GA3), and the possible interaction between the herbicide and the plant hormone during germination of sorghum seeds. GA3 decreased antioxidant enzyme activity in embryos, and the over accumulation of hydrogen peroxide (H2O2) in 1000 mM GA3-treated seeds resulted in the lowest germinability among treatments. The deleterious effects of glyphosate on germination rate, in contrast, were not related to H2O2 accumulation, but to its interference with the mitochondrial electron transport chain. However, interactions among glyphosate, GA3 and H2O2 during seed germination were observed. Similar to paclobutrazol, glyphosate appears to interfere with the de novo synthesis of gibberellin, which modulates seed germination through oxidative metabolism. Seeds experiencing increased oxidative status due to GA3 (100 mM) or H2O2 (50 mM) applications had the effects of glyphosate on germination rate reversed. Since decreased ATP synthesis is a secondary effect of glyphosate, increased H2O2 concentrations in embryos must facilitate germination by decreasing the energy required by ATP-demanding metabolism. Our results showed that glyphosate affect seed germination of sorghum, and that the herbicide interacts with oxidative and gibberellin metabolisms.


Assuntos
Germinação/efeitos dos fármacos , Giberelinas/metabolismo , Glicina/análogos & derivados , Herbicidas/farmacologia , Peróxido de Hidrogênio/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Sorghum/metabolismo , Antioxidantes/metabolismo , Grão Comestível/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Glicina/farmacologia , Sementes/efeitos dos fármacos , Glifosato
9.
Sci Total Environ ; 651(Pt 2): 2671-2678, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30463122

RESUMO

Their continuous release into the environment, associated with their inherent biological activity, has motivated investigations into the detrimental effects of antibiotics and herbicides in natural and agricultural ecosystems. In this study, the interactive effects of the antibiotic ciprofloxacin (Cipro) and the herbicide Roundup on seed germination and root development were investigated. Although both compounds act as inhibitors of the mitochondrial electron transport chain in seeds, neither Cipro nor Roundup disrupted germinability of maize seeds. However, Cipro accelerated germination by promoting ROS accumulation in seeds, while the stimulatory effect of Roundup on ROS-scavenging enzymes (catalase and ascorbate peroxidase) seems to prevent ROS-signaling, delaying the germination process. Roundup reduced root elongation, possibly due to its interference with auxin production, thereby preventing cell division, while Cipro stimulated root elongation by increasing root oxidative status. Cipro and Roundup showed antagonistic effects on maize seeds and root physiology. The presence of the antibiotic is likely not to disturb plant development; however, its stimulatory effects were not sufficient to overcome the deleterious effects of Roundup. According to our results, glyphosate-based herbicides must be carefully used during maize cropping and although antibiotics such as Cipro may not negatively impact agricultural production, their accumulation by crops must be investigated since this can be a pathway of antibiotic-insertion into the food chain.


Assuntos
Antibacterianos/toxicidade , Ciprofloxacina/toxicidade , Germinação/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/toxicidade , Testes de Toxicidade , Zea mays/efeitos dos fármacos , Catalase/metabolismo , Glicina/toxicidade , Sementes/efeitos dos fármacos , Zea mays/fisiologia , Glifosato
10.
Chemosphere ; 202: 410-419, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29579676

RESUMO

The physiological responses of the aquatic liverwort Ricciocarpus natans to ciprofloxacin (Cipro) exposure under different growth temperatures were investigated. Cipro appears to act as an inhibitor of mitochondrial Complex III by blocking the oxidation of quinol, resulting in the formation of hydrogen peroxide (H2O2). H2O2 accumulation upon Cipro exposure is responsible for decreased photosynthesis in plants. The amount of H2O2 in plants is kept under control by antioxidant enzymes, whose activities are central to the responses of plants to Cipro yet are influenced by temperature. Increased temperature favored Cipro uptake by plants as well as its deleterious effects on mitochondrial activity; however, it also favored the activity of antioxidant enzymes, thereby preventing the exacerbation of the deleterious effects of Cipro. The uptake of Cipro by plants appears to be largely a passive process, although some uptake must be driven by an energy-consuming process. Ricciocarpus natans should be considered for programs aimed at the reclamation of Cipro since this plant exhibits high Cipro-tolerance, the capacity for accumulation and increased uptake rates of the antibiotic with increasing temperatures (from 20 to 30 °C).


Assuntos
Ciprofloxacina/farmacocinética , Hepatófitas/metabolismo , Temperatura , Antibacterianos/toxicidade , Antioxidantes , Ciprofloxacina/toxicidade , Mudança Climática , Hepatófitas/enzimologia , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/farmacologia , Fotossíntese/efeitos dos fármacos , Plantas/metabolismo
11.
Environ Pollut ; 232: 293-299, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28958725

RESUMO

We investigated the ability of the aquatic fern Azolla to take up ciprofloxacin (Cipro), as well as the effects of that antibiotic on the N-fixing process in plants grown in medium deprived (-N) or provided (+N) with nitrogen (N). Azolla was seen to accumulate Cipro at concentrations greater than 160 µg g-1 dry weight when cultivated in 3.05 mg Cipro l-1, indicating it as a candidate for Cipro recovery from water. Although Cipro was not seen to interfere with the heterocyst/vegetative cell ratios, the antibiotic promoted changes with carbon and nitrogen metabolism in plants. Decreased photosynthesis and nitrogenase activity, and altered plant's amino acid profile, with decreases in cell N concentrations, were observed. The removal of N from the growth medium accentuated the deleterious effects of Cipro, resulting in lower photosynthesis, N-fixation, and assimilation rates, and increased hydrogen peroxide accumulation. Our results shown that Cipro may constrain the use of Azolla as a biofertilizer species due to its interference with nitrogen fixation processes.


Assuntos
Antibacterianos/toxicidade , Ciprofloxacina/toxicidade , Gleiquênias/fisiologia , Poluentes Químicos da Água/toxicidade , Gleiquênias/crescimento & desenvolvimento , Nitrogênio/metabolismo , Fixação de Nitrogênio , Fotossíntese/efeitos dos fármacos , Testes de Toxicidade , Água/metabolismo
12.
Plant Physiol Biochem ; 118: 168-177, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28641139

RESUMO

Little information is currently available concerning the mechanisms controlling palm seed germination. We compared the anatomical and physiological aspects of seeds of two neotropical palm species showing different levels of dormancy. The seeds of Attalea vitrivir and Butia capitata were evaluated for the endogenous contents of hormones (ABA, GAs, CKs, BRs, IAA, JA, SA and the ethylene precursor ACC) in their cotyledonary petiole and operculum (structures involved in germination control), the force necessary to displace the operculum, endo-ß-mannanase activities, and embryo cell elongation. The analyses were carried out on with intact dry and imbibed seeds as well as with seeds with the operculum mechanically removed, 2, 5 and 10 days after sowing. The germinabilities of the intact seeds of A. vitrivir and B. capitata were 68% and 3%, respectively; the removal of the operculum increased germination to more than 90% in both species. Reductions of ABA and increases in GAs contents coincided with cell elongation, although there is no evidence that hormonal balance and endo-ß-mannanase activity are involved in operculum weakening. The ratio between the embryo length and the force required for operculum displacement (EL/OF) was found to be 1.9 times greater in A. vitrivir than in B. capitata, which means that very small elongations in each cell would be sufficient to promote germination, resulting in a lower level of dormancy in the former species. EL/OF and cell growth control are therefore important for defining dormancy level in palm seeds.


Assuntos
Germinação/fisiologia , Magnoliopsida/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/metabolismo , Sementes/metabolismo , Magnoliopsida/citologia , Sementes/citologia , Especificidade da Espécie
13.
J Agric Food Chem ; 65(11): 2279-2286, 2017 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-28245120

RESUMO

We investigated the effects of different concentrations of glyphosate acid and one of its formulations (Roundup) on seed germination of two glyphosate-resistant (GR) and one non-GR variety of soybean. As expected, the herbicide affected the shikimate pathway in non-GR seeds but not in GR seeds. We observed that glyphosate can disturb the mitochondrial electron transport chain, leading to H2O2 accumulation in soybean seeds, which was, in turn, related to lower seed germination. In addition, GR seeds showed increased activity of antioxidant systems when compared to non-GR seeds, making them less vulnerable to oxidative stress induced by glyphosate. The differences in the responses of GR varieties to glyphosate exposure corresponded to their differences in enzymatic activity related to H2O2 scavenging and mitochondrial complex III (the proposed site of ROS induction by glyphosate). Our results showed that glyphosate ought to be used carefully as a pre-emergence herbicide in soybean field crop systems because this practice may reduce seed germination.


Assuntos
Germinação/efeitos dos fármacos , Glycine max/efeitos dos fármacos , Glicina/análogos & derivados , Resistência a Herbicidas , Herbicidas/farmacologia , Glicina/farmacologia , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Glycine max/crescimento & desenvolvimento , Glifosato
14.
Environ Toxicol Chem ; 36(8): 2036-2042, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28052377

RESUMO

The integrative effects of zinc (Zn; 0 mg L-1 , 75 mg L-1 , 150 mg L-1 , and 200 mg L-1 ) and temperature (25 °C, 30 °C, and 35 °C) on seed germination of the threatened Brazilian species Dimorphandra wilsonii were evaluated. Zinc effects on seed germination were only observed at 30 °C and 35 °C. By stimulating respiration rates, rising temperatures accentuate hydrogen peroxide (H2 O2 ) formation in germinating seeds in the presence of Zn. Seed Zn tolerance was related to the activation of enzymatic antioxidants, and ascorbate peroxidase (APX) activity had a central role in H2 O2 scavenging under the highest temperatures tested. Increased APX activity allowed successful germination, whereas decreasing APX activity was accompanied by decreasing germination rates in Zn-treated seeds at 35 °C. Within a scenario of future climate change, it will be extremely important to avoid increasing Zn concentrations in natural habitats that would threaten conservation efforts directed toward this endangered plant species. Environ Toxicol Chem 2017;36:2036-2042. © 2017 SETAC.


Assuntos
Mudança Climática , Fabaceae/efeitos dos fármacos , Germinação/efeitos dos fármacos , Temperatura Alta , Poluentes do Solo/toxicidade , Zinco/toxicidade , Antioxidantes/metabolismo , Brasil , Fabaceae/crescimento & desenvolvimento , Fabaceae/metabolismo , Peróxido de Hidrogênio/metabolismo , Oxirredução , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Sementes/metabolismo
15.
J Hazard Mater ; 328: 140-149, 2017 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-28110148

RESUMO

We investigate the physiological responses and antibiotic-uptake capacity of Lemna minor exposed to ciprofloxacin. Ciprofloxacin (Cipro) induced toxic effects and hormesis in plants by significantly modifying photosynthesis and respiration pathways. A toxic effect was induced by a concentration ≥1.05mg ciprofloxacin l-1 while hormesis occurs at the lowest concentration studied (0.75mg ciprofloxacin l-1). By impairing normal electron flow in the respiratory electron transport chain, ciprofloxacin induces hydrogen peroxide (H2O2) production. The ability of plants to cope with H2O2 accumulation using antioxidant systems resulted in stimulation/deleterious effects to photosynthesis by Cipro. Cipro-induced oxidative stress was also associated with the ability of L. minor plants to uptake the antibiotic and, therefore, with plant-uptake capacity. Our results indicate that instead of being a photosystem II binding molecule, Cipro induces oxidative stress by targeting the mitochondrial ETC, which would explain the observed effects of the antibiotic on non-target eukaryotic organisms. The selection of plants species with a high capacity to tolerate oxidative stress may constitute a strategy to be used in Cipro-remediation programs.


Assuntos
Antibacterianos/toxicidade , Araceae/efeitos dos fármacos , Ciprofloxacina/toxicidade , Metabolismo Energético/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Antibacterianos/metabolismo , Araceae/metabolismo , Clorofila/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Peróxido de Hidrogênio/análise , Peróxido de Hidrogênio/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/efeitos dos fármacos
16.
Environ Pollut ; 220(Pt A): 452-459, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27726979

RESUMO

Glyphosate-formulations are widely used in the Brazilian Cerrado (neotropical savanna) with little or no control, threatening population of the endangered species Dimorphandra wilsonii. We investigated the toxicity of different concentrations (0, 5, 25 and 50 mg l-1) of glyphosate acid and one of its formulations (Roundup®) on seed germination in D. wilsonii. Glyphosate acid and Roundup drastically decreased seed germination by decreasing seed respiration rates. The activation of antioxidant enzymes, ascorbate peroxidase and catalase assure no hydrogen peroxide accumulation in exposed seeds. Glyphosate acid and the Roundup-formulation negatively affected the activities of enzymes associated with the mitochondrial electron transport chain (ETC), with Complex III as its precise target. The toxicity of Roundup-formulation was greater than that of glyphosate acid due to its greater effects on respiration. The herbicide glyphosate must impair D. wilsonii seed germination by disrupting the mitochondrial ETC, resulting in decreased energy (ATP) production. Our results therefore indicate the importance of avoiding (or closely regulating) the use of glyphosate-based herbicides in natural Cerrado habitats of D. wilsonni as they are toxic to seed germination and therefore threaten conservation efforts. It will likewise be important to investigate the effects of glyphosate on the seeds of other species and to investigate the impacts of these pesticides elsewhere in the world.


Assuntos
Fabaceae/efeitos dos fármacos , Germinação/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/toxicidade , Animais , Antioxidantes/metabolismo , Brasil , Glicina/toxicidade , Sementes/metabolismo , Glifosato
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