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1.
Chemosphere ; 254: 126918, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957302

RESUMO

The increasing application of various surfactants nowadays, may lead to the contamination of the natural environment and represent potential threat to terrestrial higher plants. In this article, the effect of 13 surfactants, with dodecyl alkyl chain and various aromatic (imidazolium, pyridinium, thiazolium) and aliphatic (guanidinium, ammonium, thiosemicarbazidium) polar heads, on germination, development and growth of wheat and cucumber was investigated. The study aimed to prove how changes in lipophilicity of surfactants and their various structural modifications (existence of the aliphatic or aromatic polar group, the introduction of oxygen and sulfur) influence toxicity towards investigated plants. The calculated lipophilic parameter (AlogP) is shown to be a useful parameter for predicting potential toxicity of the compound. The strategy of using surfactants with aliphatic polar heads instead of aromatic prove to be a promising strategy in reducing harmful effect, as well as the introduction of polar groups in the structure of cation. From all investigated compounds, surfactants with imidazolium polar head displayed the most harmful effect towards wheat and cucumber. The cucumber seeds were more sensitive to the addition of surfactants comparing to wheat. All obtained experimental results were additionally investigated using computational methods, simulating the transport of surfactants through a lipid bilayer. The influence of cation tendency to fit in lipid bilayer structure was correlated with toxicity. For the first time, it is concluded that cation ability to mimic the structure of bilayer have less harmful effect on plant development.


Assuntos
Cucumis sativus/efeitos dos fármacos , Imidazóis/toxicidade , Compostos de Piridínio/toxicidade , Tensoativos/toxicidade , Triticum/efeitos dos fármacos , Cátions , Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Cucumis sativus/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Imidazóis/química , Bicamadas Lipídicas/química , Simulação de Dinâmica Molecular , Compostos de Piridínio/química , Compostos de Piridínio/farmacologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tensoativos/química , Triticum/crescimento & desenvolvimento
2.
Ecotoxicol Environ Saf ; 203: 111054, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888616

RESUMO

Quinclorac (3,7-dichloroquinoline-8-carboxylic acid, QNC) is a highly selective auxin herbicide that is typically applied to paddy rice fields. Its residue is a serious problem in crop rotations. In this study, Oryza sativa L. seedlings was used as a model plant to explore its biochemical response to abiotic stress caused by QNC and nZVI coexposure, as well as the interactions between QNC and nZVI treatments. Exposure to 5 and 10 mg/L QNC reduced the fresh biomass by 26.6% and 33.9%, respectively, compared to the control. The presence of 50 and 250 mg/L nZVI alleviated the QNC toxicity, but the nZVI toxicity was aggravated by the coexist of QNC. Root length was enhanced upon exposure to low or medium doses of both QNC and nZVI, whereas root length was inhibited under high-dose coexposure. Both nZVI and QNC, either alone or in combination, significantly inhibited the biosynthesis of chlorophyll, and the inhibition rate increased with elevated nZVI and QNC concentration. It was indicated that nZVI or QNC can affect the plant photosynthesis, and there was a significant interaction between the two treatments. Effects of QNC on the antioxidant response of Oryza sativa L. differed in the shoots and roots; generally, the introduction of 50 and 250 mg/L nZVI alleviated the oxidative stress (POD in shoots, SOD and MDA in roots) induced by QNC. However, 750 mg/kg nZVI seriously damaged Oryza sativa L. seedlings, which likely resulted from active iron deficiency. QNC could be removed from the culture solution by nZVI; as a result, nZVI suppressed QNC uptake by 20%-30%.


Assuntos
Antioxidantes/metabolismo , Ferro/toxicidade , Nanopartículas/toxicidade , Oryza/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Quinolinas/toxicidade , Poluentes do Solo/toxicidade , Transporte Biológico , Biomassa , Clorofila/metabolismo , Relação Dose-Resposta a Droga , Interações Medicamentosas , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
3.
Bull Environ Contam Toxicol ; 105(4): 553-558, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32918155

RESUMO

The aim of this study was to evaluate, through nonlinear regression models, the initial development of soybean (Glycine max L. Merr. cv. BRS 257) in soil supplemented with different copper levels. The experiment was performed in a greenhouse under natural light and temperature conditions. The seeds were sowed in soil containing different copper levels (11.20, 32.28, 52.31, 64.51, 79.42, 117.70, 133.53, 144.32, or 164.00 mg kg- 1). Germination percentage was not affected by the increase of copper content in the soil, but there was a delay in the germination process. There was no influence of copper levels on the seedling emergence speed index until 98.42 mg kg- 1; however, higher copper amounts reduced this parameter. Low copper concentrations increased plant development, but higher concentrations compromised mainly root growth. Overall, these results suggest that copper supplementation in the soil exerted dose-dependent dual effects on soybean seedlings.


Assuntos
Cobre/efeitos adversos , Germinação/efeitos dos fármacos , Poluentes do Solo/efeitos adversos , Soja/efeitos dos fármacos , Relação Dose-Resposta a Droga , Dinâmica não Linear , Análise de Regressão , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Solo/química , Soja/crescimento & desenvolvimento
4.
Ecotoxicol Environ Saf ; 203: 111007, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888586

RESUMO

Soil acidification is one of the crucial global environmental problems, affecting sustainable land use, crop yield, and ecosystem stability. Previous research reported the tolerance of crops to acid soil stress. However, the molecular response of woody plant to acid conditions remains largely unclear. Rhododendron L. is a widely distributed woody plant genus and prefers to grow in acidic soils. Herein, weighted gene coexpression network analysis was performed on R. protistum var. giganteum seedlings subjected to five pH treatments (3.5, 4.5, 5.5, 6.0, 7.0), and their ecophysiological characteristics were determined for the identification of their molecular responses to acidic environments. Through pairwise comparison, 855 differentially expressed genes (DEGs) associated with photosynthesis, cell wall, and phenylpropanoid metabolism were identified. Most of the DEGs related to photosynthesis and cell wall were up-regulated after pH 4.5 treatment. Results implied that the species improves its photosynthetic abilities and changes its cell wall characteristics to adapt to acidic conditions. Weighted gene co-expression network analyses showed that most of the hub genes were annotated to the biosynthetic pathways of ribosomal proteins and photosynthesis. Expression pattern analysis showed that genes encoding subunit ribosomal proteins decreased at pH 7.0 treatment, suggesting that pH 7.0 treatment led to cell injury in the seedlings. The species regulates protein synthesis in response to high pH stress (pH 7.0). The present study revealed the molecular response mechanism of woody plant R. protistum var. giganteum to acid environments. These findings can be useful in enriching current knowledge of how woody species adapt to soil acidification under global environmental changes.


Assuntos
Ácidos/farmacologia , Parede Celular/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Madeira/efeitos dos fármacos , Parede Celular/genética , Parede Celular/metabolismo , Perfilação da Expressão Gênica , Redes Reguladoras de Genes/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Fotossíntese/genética , Plântula/efeitos dos fármacos , Plântula/metabolismo , Solo/química , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Madeira/genética , Madeira/metabolismo
5.
Ecotoxicol Environ Saf ; 203: 111016, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888590

RESUMO

Selenium (Se) is considered a beneficial element to higher plants based on its regulation of antioxidative system under abiotic or biotic stresses. However, the limit of beneficial and toxic physiological effects of Se is very narrow. In the present study, the antioxidant performance, nutritional composition, long-distance transport of Se, photosynthetic pigments, and growth of Coffea arabica genotypes in response to Se concentration in solution were evaluated. Five Coffea arabica genotypes (Obatã, IPR99, IAC125, IPR100 and Catucaí) were used, which were grown in the absence and presence of Se (0 and 1.0 mmol L-1) in nutrient solution. The application of 1 mmol L-1 Se promoted root browning in all genotypes. There were no visual symptoms of leaf toxicity, but there was a reduction in the concentration of phosphorus and sulfur in the shoots of plants exposed to high Se concentration. Except for genotype Obatã, the coffee seedlings presented strategies for regulating Se uptake by reducing long-distance transport of Se from roots to shoots. The concentrations of total chlorophyll, total pheophytin, and carotenoids were negatively affected in genotypes Obatã, IPR99, and IAC125 upon exposure to Se at 1 mmol L-1. H2O2 production was reduced in genotypes IPR99, IPR100, and IAC125 upon exposure to Se, resulting in lower activity of superoxide dismutase (SOD), and catalase (CAT). These results suggest that antioxidant metabolism was effective in regulating oxidative stress in plants treated with Se. The increase in sucrose, and decrease in SOD, CAT and ascorbate peroxidase (APX) activities, as well as Se compartmentalization in the roots, were the main biochemical and physiological modulatory effects of coffee seedlings under stress conditions due to excess of Se.


Assuntos
Antioxidantes/metabolismo , Coffea/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Selênio/farmacologia , Coffea/genética , Coffea/metabolismo , Coffea/fisiologia , Genótipo , Oxirredução , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/metabolismo , Plântula/fisiologia , Selênio/análise , Selênio/metabolismo , Especificidade da Espécie
6.
Ecotoxicol Environ Saf ; 204: 111104, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32791360

RESUMO

Since development of antioxidant defence system is high energy demanding event, innate defence system and stress tolerance of plant is strictly governed by plant age. This study is aimed towards evaluating variation of tolerance in germinating seeds and seedlings of Oryza sativa L. cv. Swarna against nano-scale zero valent iron (nZVI). A comparative study of several physiological and biochemical parameters have been carried out among 2 distinct plant groups, Group I treated with variable concentrations of nZVI (50, 100, 150 and 200 mg L-1) during germination and Group II treated with similar nZVI doses on 7th day after germination. Upon treatment with higher nZVI concentrations, Group I seedlings showed susceptibility towards oxidative stress while Group II seedlings showed tolerance against these higher doses of nZVI. Significant growth enhancement was observed upon treatment with 50-150 mg L-1 nZVI, since up-regulation of plant's endogenous antioxidant system protected relatively aged Group II seedlings from oxidative damages. Hierarchical clustering based on overall physiological, biochemical and stress parameters confirmed that in Group I seedlings 100-200 mg L-1 nZVI treatments were toxic where as in Group II seedlings 50-150 mg L-1 nZVI treatments showed growth promoting effects. This differential response is due to developmental stage related resistance in plants.


Assuntos
Germinação/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Oryza/crescimento & desenvolvimento , Antioxidantes/metabolismo , Ferro/metabolismo , Oryza/efeitos dos fármacos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Sementes/metabolismo
7.
Artigo em Inglês | MEDLINE | ID: mdl-32666147

RESUMO

Several invasive alien plants (IAP) can trigger evidently allelopathy on the seed germination and seedling growth (SgSg) of native plant species (NPS). The getting worse condition with heavy metal pollution (e.g., cadmium) can significantly impact SgSg of plant species. Silicon can offset the adverse effects of environmental pressure on the growth and development of plant species. Thus, it is important to evaluate the influences of silicon on the allelopathy of IAP on SgSg of NPS under cadmium stress to better understand the mechanism driving the successful colonization of IAP. This study focuses on the allelopathy of the infamous IAP Solidago canadensis L. (Canada goldenrod; by using leaf extracts) on SgSg of NPS Lactuca sativa L. under the separated and mixed silicon and cadmium addition. S. canadensis triggers notably allelopathy on SgSg of L. sativa and gradually upsurges with increasing leaf extract concentration. Thus, the growth performance of NPS will be gradually reduced with an increasing degree of S. canadensis invasion. Cadmium evidently declines SgSg of L. sativa due to the broken balance of plant species for nutrient absorption. The mixed S. canadensis leaf extracts and cadmium synergistically impact seed germination of L. sativa but antagonistically affect seedling growth of L. sativa. The mixed silicon and cadmium intensify the allelopathy of S. canadensis on SgSg of L. sativa probably due to the increased effective content of cadmium in plant roots under silicon addition. Thus, the mixed silicon and cadmium will be advantageous to the following invasion process of IAP largely via the depressed SgSg of NPS.


Assuntos
Alelopatia/efeitos dos fármacos , Cádmio/efeitos adversos , Alface/crescimento & desenvolvimento , Substâncias Protetoras/farmacologia , Silício/farmacologia , Poluentes do Solo/efeitos adversos , Solidago/efeitos dos fármacos , Germinação/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Solidago/fisiologia
8.
Ecotoxicol Environ Saf ; 203: 110978, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678757

RESUMO

In this study, hydroponic experiments were conducted to elucidate mechanism(s) that are associated with differential effects of low (5 µM) and high (25 µM) dose of cadmium (Cd) stress in tomato. Furthermore, emphasis has also been focused on any involvement of endogenous hydrogen sulfide (H2S) in differential behaviour of low and high doses of Cd stress. At low dose of Cd, root growth i.e. root fresh weight, length and fitness did not significantly alter when compared to the control seedlings. Though at low dose of Cd, cellular accumulation of Cd was slightly increased but this was accompanied by higher endogenous H2S and phytochelatins, L-cysteine desulfhydrase (DES) activity, activities of glutathione biosynthetic and AsA-GSH cycle enzymes, and maintained redox status of ascorbate and glutathione. However, addition of hypotaurine (HT, a scavenger of H2S) resulted in greater toxicity, even at low dose of Cd, and these responses resembled with higher dose of Cd stress such as greater decline in root growth, endogenous H2S and phytochelatins, activities of DES, glutathione biosynthesis and AsA-GSH cycle enzymes, disturbed redox status of ascorbate and glutathione which collectively led to higher oxidative stress in tomato roots. Moreover, addition of HT with higher dose of Cd also further enhanced its toxicity. Collectively, the results showed that differential behaviour of low and high dose of Cd stress is mediated by differential regulation of biochemical attributes in which endogenous H2S has a crucial role.


Assuntos
Cádmio/toxicidade , Sulfeto de Hidrogênio/metabolismo , Lycopersicon esculentum/efeitos dos fármacos , Fitoquelatinas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Ácido Ascórbico/metabolismo , Glutationa/metabolismo , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
9.
Chemosphere ; 260: 127533, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32679374

RESUMO

In recent decades, nanoscale zero valent iron (nZVI) has been found to be a promising approach for heavy metal remediation. This study is the first report highlighting the role of nZVI to ameliorate Cadmium (Cd) stress in rice along with its effects in expressions of transporter genes, agronomic parameters and grain nutrient status. Initially, 3 concentration of Cd (10, 50, 250 µM) and nZVI (50, 100, 200 mg L-1) were selected. PCA analysis based on growth parameters, photosynthetic pigment contents and lipid peroxidation rate confirmed that 100 mg L-1 nZVI was most suitable for remediation of 10 µM Cd. It was evident that, nZVI can alleviate Cd-induced toxic effects by enhancing antioxidant defense mechanisms and other physiological processes in plants. nZVI treated rice seedlings also showed upregulation of phytochelatins which aided in Cd chelation within vacuoles. Study of root morphology with scanning electron microscopy and ROS imaging with confocal microscopy confirmed that nZVI could alleviate oxidative stress due to Cd uptake. In nZVI treated rice seedlings, gene expressions of iron (Fe) transporters (like, IRT1,IRT2,YSL2,YSL15) which are responsible for both Fe and Cd uptake were significantly down-regulated whereas, OsVIT1 and OsCAX4 genes were over expressed which lead to sequestration of Cd in vacuoles. Cd localization assay with leadmium proved that Cd translocation was reduced with nZVI treatment. To further validate our findings a pot experiment was carried out where it was found that nZVI could immobilize Cd in soil prevented accumulation of Cd in rice grains in addition to improving yield.


Assuntos
Cádmio/química , Poluentes do Solo/química , Antioxidantes/metabolismo , Transporte Biológico , Cádmio/análise , Grão Comestível/química , Ferro/análise , Metais Pesados/análise , Oryza/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fitoquelatinas/metabolismo , Plântula/efeitos dos fármacos , Solo , Poluentes do Solo/análise
10.
Ecotoxicol Environ Saf ; 202: 110854, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32585484

RESUMO

Atrazine as a kind of herbicide could cause damage to the sensitive plants. Though plant growth promoting rhizobacteria (PGPR) have been proven with the potential to enhance the resistance of plants against various abiotic stresses, whether it could alleviate phytotoxicity caused by atrazine is sill unclear. In present study, the effects of strain Pseudomonas chlororaphis PAS18, a kind of PGPR enable to produce indole-3-acetic acid (IAA), on the growth and physiological responses of Pennisetum americanum (L.) K.Schum seedlings were investigated under three different levels (0, 20 and 100 mg kg-1) of atrazine in pot experiment. The results suggest that strain PAS18 could alleviate the growth and physiological interference caused by 20 mg kg-1 of atrazine. Physiological analysis showed strain PAS18 could further decrease the damaged extent of photosystem II, superoxide radical level and malondialdehyde content of test plant via up-regulating psbA expression, enhancing superoxide dismutase activity and reducing atrazine accumulation in the test plant. Moreover, ion flux measurements suggest that IAA could alleviate the Ca2+ exflux state of the test plant which caused by atrazine stress. Hence, it is plausible that strain PAS18 could alleviate atrazine-induced stress to P. americanum by enhancing the photosystem II repair and antioxidant defense ability as well as balancing the Ca2+ flux.


Assuntos
Atrazina/toxicidade , Ácidos Indolacéticos/metabolismo , Pennisetum/fisiologia , Pseudomonas chlororaphis/fisiologia , Antioxidantes/metabolismo , Atrazina/metabolismo , Tolerância a Medicamentos , Herbicidas/metabolismo , Malondialdeído/metabolismo , Pennisetum/efeitos dos fármacos , Fotossíntese , Pseudomonas chlororaphis/metabolismo , Plântula/efeitos dos fármacos , Estresse Fisiológico
11.
Ecotoxicol Environ Saf ; 201: 110853, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32563160

RESUMO

The phytotoxicity caused by 500 µM ZnSO4.7H2O and its detoxifying by co-application of 100 µM of MT melatonin (MT) and glutathione (GSH) in 6-week-old safflower plants have been investigated. Reduced biomass production and total chlorophyll content on the one hand and increased content of hydrogen peroxide (H2O2), malondialdehyde (MDA) with increase in lipoxygenase activity, on the other hand, showed Zn- induced oxidative damage in safflower seedlings. When MT, GSH and especially MT + GSH exogenously were applied to Zn-stressed seedlings, the content of H2O2, MDA and the activity of lipoxygenase considerably decreased. In Zn- treated seedlings, the application of these signaling molecules led to a considerable increment in ascorbate (ASC), GSH and phytochelatin (PC) contents along with the induction of activity of antioxidant enzymes including ascorbate-glutathione cycle enzymes when compared with the plants stressed with Zn only. In Zn-stressed safflower seedlings treated with MT, GSH and MT + GSH, decreased activity of enzymes involved in glyoxalase system may be associated with the role of MT and GSH in reducing Zn uptake and reducing Zn-induced toxicity and subsequently, lower plant's defense responses. The data showed that the effects of MT and GSH, in particular, the combination of these two molecules in reducing Zn uptake and diminishing its accumulation in the shoots of safflower seedlings, and also the participation of MT and GSH on increasing plant ability to tolerate high amount of Zn through stimulation of various antioxidant defense systems suggest them as suitable candidates to better the survival of safflower in soils contaminated with Zn excess.


Assuntos
Antioxidantes/farmacologia , Carthamus tinctorius/efeitos dos fármacos , Glutationa/farmacologia , Melatonina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Zinco/toxicidade , Ácido Ascórbico/metabolismo , Carthamus tinctorius/crescimento & desenvolvimento , Carthamus tinctorius/metabolismo , Clorofila/metabolismo , Sinergismo Farmacológico , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Oxirredução , Fitoquelatinas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
12.
PLoS One ; 15(6): e0234045, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32544208

RESUMO

A study was conducted to determine the impact of applying different sources of Mg, namely kieserite, ground magnesium limestone (GML) and Mg-rich synthetic gypsum (MRSG) on an acid tropical soil, oil palm growth and production. Besides high amount of Mg and Ca, MRSG contains S. Exchangeable Ca in the untreated soil of the plantation was 0.64 cmolc kg-1, but its critical level to sustain oil palm growth was 0.9 cmolc kg-1. MRSG was applied in the plantation as Mg-fertilizer; however, since Ca is also a limiting nutrient, oil palm growth was correlated (r = 0.69) with Ca supplied by the MRSG. Mg needed to sustain oil palm production is normally supplied by kieserite. Its requirement can be met at a lower cost compared to that of the kieserite by using MRSG. Due to MRSG treatment, exchangeable Ca in the soil increased steadily to satisfy the requirement of oil palm for fruit bunches production. From the glasshouse and field study, it was observed that MRSG applied at 1.5 times the recommended rate gave results comparable to that of the kieserite. MRSG treatment resulted in the increase of soil pH to >5 that precipitated Al3+ as inert Al-hydroxides, which eventually enhanced oil palm seedlings growth. Thus, MRSG can also replace GML to increase soil pH and satisfy the Ca and Mg requirement of oil palm. It can be concluded that MRSG has the potential to be used as a source of Mg as well as Ca for oil palm grown on acidic soil.


Assuntos
Sulfato de Cálcio/química , Sulfato de Cálcio/farmacologia , Magnésio/química , Magnoliopsida/efeitos dos fármacos , Magnoliopsida/crescimento & desenvolvimento , Solo/química , Calibragem , Concentração de Íons de Hidrogênio , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento
13.
Chemosphere ; 257: 127241, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32526468

RESUMO

The role of endogenous hydrogen sulphide (H2S) in silicon-induced improvement in boron toxicity (BT) tolerance in pepper plants was studied. Two-week old seedlings were subjected to control (0.05 mM B) or 2.0 mM BT in a nutrient solution. These two treatments were combined with 2.0 mM Si. BT caused considerable reduction in biomass, chlorophyll a &b, photosystem II maximum quantum efficiency (Fv/Fm), glutathione and ascorbate in the pepper seedlings. However, it enhanced malondialdehyde (MDA) and hydrogen peroxide, electrolyte leakage, proline, H2S, and activities of catalase, superoxide dismutase, peroxidase, and L-DES. Silicon stimulated growth, proline content and activities of various antioxidant biomolecules and enzymes, leaf Ca2+, K+ and N, endogenous H2S and L-DES activity, but reduced H2O2 and MDA contents, membrane leakage and leaf B. Silicon-induced B tolerance was further enhanced by 0.2 mM NaHS, a H2S donor. A scavenger of H2S, hypotaurine (0.1 mM HT), was supplied together with Si and Si + NaHS to assess the involvement of H2S in Si-induced BT tolerance of pepper plants. Hypotaurine inverted the positive role of Si on the antioxidant defence system by reducing endogenous H2S, but NaHS supply along with Si + HT reversed the negative effects of HT, showing that H2S participated in Si-induced BT tolerance of pepper plants.


Assuntos
Boro/toxicidade , Sulfeto de Hidrogênio/química , Poluentes do Solo/toxicidade , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Catalase/metabolismo , Clorofila A , Glutationa/metabolismo , Peróxido de Hidrogênio/farmacologia , Malondialdeído , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Silício/química , Sulfetos , Superóxido Dismutase/metabolismo
14.
Chemosphere ; 257: 127247, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32534296

RESUMO

Chelate-assisted phytoextraction by high biomass producing macrophyte plant Typha latifolia L. commonly known as cattail, is gaining much attention worldwide. The present study investigated the effects of Lead (Pb) and Mercury (Hg) on physiology and biochemistry of plant, Pb and Hg uptake in T. latifolia with and without citric acid (CA) amendment. The uniform seedlings of T. latifolia were treated with various concentrations in the hydroponics as: Pb and Hg (1, 2.5, 5 mM) each alone and/or with CA (5 mM). After four weeks of treatments, the results revealed that Pb and Hg significantly reduced the plant agronomic traits as compare to non-treated plants. The addition of CA improved the plant physiology and enhanced the antioxidant enzymes activities to overcome Pb and Hg induced oxidative damage and electrolyte leakage. Our results depicted that Pb and Hg uptake and accumulation by T. latifolia was dose depend whereas, the addition of CA further increased the concentration and accumulation of Pb and Hg by up to 22 & 35% Pb and 72 & 40% Hg in roots, 25 & 26% Pb and 85 & 60% Hg in stems and 22 & 15 Pb and 100 & 58% Hg in leaves respectively compared to Pb and Hg treated only plants. On other hand, the root-shoot translocation factor was ≥1 and bioconcentration factor was also ≥2 for both Pb & Hg. The results also revealed that T. latifolia showed greater tolerance towards Hg and accumulated higher Hg in all parts compared with Pb.


Assuntos
Ácido Cítrico/metabolismo , Chumbo/metabolismo , Mercúrio/metabolismo , Poluentes do Solo/metabolismo , Typhaceae/fisiologia , Biodegradação Ambiental , Biomassa , Folhas de Planta/química , Raízes de Plantas/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/análise , Typhaceae/efeitos dos fármacos
15.
Chemosphere ; 259: 127445, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593005

RESUMO

Iron oxide nanoparticles (nFe2O3)-filled materials have been widely employed in various products and their effects on plants have attracted considerable attention because of their potential release into the environment. Currently, numerous studies reporting the influences of iron-bearing nanoparticles on plants are focused on root or seed exposure. However, plants exposed to atmospheric iron-bearing nanoparticles through the leaves and their impacts on plants are still not well understood. This study focused on the uptake, translocation, and effects of foliar exposure of nFe2O3 on wheat seedlings. Wheat seedlings were foliar applied to various concentrations of nFe2O3 (0, 60 and 180 µg per plant) for 1, 7, 14 or 21 d. Our results demonstrated that after exposure for 21 d, the concentrations of Fe in leaves, stems, and roots were 1100, 280 and 160 µg kg-1, respectively. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), as well as the backscattered electron (BSE) images, revealed the stomatal opening was likely the pathway for nFe2O3 uptake. Analysis of the transfer rate, translocation of Fe from leaves to stems and roots, suggested the involvement of plant Fe regulation processes. Particularly, the antioxidant enzymatic activities and malondialdehyde levels in leaves were modified, which was ascribed to the excessive hydroxyl radical (OH) generated via the Fenton-like reaction mediated by nFe2O3. Finally, the OH facilitated the degradation of chlorophyll, posting a negative impact on the photosynthesis, and thus inhibited the biomass production. These findings are meaningful to understand the fate and physiological effects of atmospheric nFe2O3 in crops.


Assuntos
Compostos Férricos/toxicidade , Nanopartículas/toxicidade , Fotossíntese/efeitos dos fármacos , Triticum/efeitos dos fármacos , Antioxidantes/metabolismo , Transporte Biológico , Biomassa , Clorofila/metabolismo , Compostos Férricos/metabolismo , Ferro/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Sementes/metabolismo , Triticum/metabolismo , Triticum/fisiologia
16.
Ecotoxicol Environ Saf ; 201: 110735, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32480163

RESUMO

Methyl jasmonate (Me-JA) is a plant growth regulator known for modulating plant responses to various abiotic and biotic stresses. The unavoidable arsenic (As) contamination in rice (Oryza sativa) results in reduced crop yield and greater carcinogenic risk to humans. The present work examines the significance of Me-JA induced molecular signaling and tolerance towards arsenic toxicity in rice. The arsenite (AsIII; 25 µM) stress hampered the overall growth and development of the rice seedling. However, the co-application (25 µM AsIII+0.25 µM Me-JA) resulted in increased biomass, chlorophyll content, enhanced antioxidant enzyme activities as compared to AsIII treated plants. The co-application also demonstrated a marked decrease in malondialdehyde content, electrolyte leakage and accumulation of total AsIII content (root + shoot) as compared to AsIII treated plants. The co-application also modulated the expression of genes involved in downstream JA signaling pathway (OsCOI, OsJAZ3, OsMYC2), AsIII uptake (OsLsi1, OsLsi2, OsNIP1;1, OsNIP3;1), translocation (OsLsi6, and OsINT5) and detoxification (OsNRAMP1, OsPCS2, and OsABCC2) which revealed the probable adaptive response of the rice plant to cope up arsenic stress. Our findings reveal that Me-JA alleviates AsIII toxicity by modulating signaling components involved in As uptake, translocation, and detoxification and JA signaling in rice. This study augments our knowledge for the future use of Me-JA in improving tolerance against AsIII stress.


Assuntos
Acetatos/farmacologia , Arsênico/toxicidade , Ciclopentanos/farmacologia , Oryza/efeitos dos fármacos , Oxilipinas/farmacologia , Reguladores de Crescimento de Planta/farmacologia , Acetatos/metabolismo , Arsênico/metabolismo , Arsenitos/metabolismo , Arsenitos/toxicidade , Transporte Biológico , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Humanos , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Transdução de Sinais/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos
17.
Food Chem ; 331: 127282, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32559597

RESUMO

Phenolics are important secondary metabolites in plants with strong antioxidant effects. Seeds germination and exogenous stimulation could activate endogenous enzymes to enhance the content of phenolic acids and flavonoids. Barley seeds geminated under NaCl (1-20 mM) treatment to evaluate the accumulation of phenolics in this study. Results showed that NaCl treatment significantly enhanced the growth of seedlings, especially bud length. NaCl treatment up-regulated genes and proteins expression of phenylalanine ammonia lyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate-CoA ligase (4CL), resulting in the enhancement of their activities. As a result, phenolic acids and flavonoids contents increased by 11.19% and 32.54%, respectively, in which gallic acid, protocatechuic, fisetin, myricetin and quercetin were affected mostly. Moreover, NaCl treatment enhanced 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging capacity. Hence, NaCl stimulated the synthesis of phenolic components via enhancing gene, protein expression and the activity of key enzymes.


Assuntos
Hordeum/efeitos dos fármacos , Hordeum/metabolismo , Fenóis/metabolismo , Plântula/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Antioxidantes/análise , Flavonoides/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Germinação/efeitos dos fármacos , Fenóis/análise , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/metabolismo , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/metabolismo , Plântula/metabolismo , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Transcinamato 4-Mono-Oxigenase/genética , Transcinamato 4-Mono-Oxigenase/metabolismo
18.
Chemosphere ; 258: 127350, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554012

RESUMO

The adverse effects of glyphosate herbicide on plants are well recognised, however, potential hormetic effects have not been well studied. This study aimed to use tomato as a model organism to explore the potential hormetic effects of glyphosate in water (0-30 mg L-1) and in compost soil (0-30 mg kg-1). The growth-promoting effects of glyphosate at concentrations of 0.03-1 mg L-1 in water or 0.03-1 mg kg-1 in compost were demonstrated in tomato for the first time. These hormetic effects were manifest as increased hypocotyl and radicle growth of seedlings germinated on paper towel soaked in glyphosate solution and also in crops which had been sprayed with glyphosate. Increased rates of photosynthesis (up to 2-fold) were observed in 4-week old crops when seeds were sown in compost amended with glyphosate and also when leaves were sprayed with glyphosate. The examination of chloroplast morphology using transmission electron microscopy revealed that the hormetic effects were associated with elongation of chloroplasts, possibly due to lateral expansion of thylakoid grana.


Assuntos
Germinação/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/toxicidade , Lycopersicon esculentum/fisiologia , Cloroplastos/efeitos dos fármacos , Produtos Agrícolas/efeitos dos fármacos , Glicina/toxicidade , Hormese/efeitos dos fármacos , Lycopersicon esculentum/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Plântula/efeitos dos fármacos , Sementes/efeitos dos fármacos , Solo
19.
Artigo em Inglês | MEDLINE | ID: mdl-32594380

RESUMO

Influence of arsenic (As) in As tolerant and sensitive rice genotypes based chloroplastic pigments, leaf gas exchange attributes and their influence on carbohydrate metabolism were investigated in the present study. As retards growth of crop plants and increase several health ailments by contaminating food chain. Photosynthetic inhibition is known to be the prime target of As toxicity due to over-production of ROS. Hydroponically grown rice seedlings of twelve cultivars were exposed to 25, 50, and 75 µM arsenate (AsV) that exerted negative impact on plastidial pigments content and resulted into inhibition of Hill activity. Internal CO2 concentration lowered gradually due to interference of As with stomatal conductance and transpiration rate that subsequently led to drop in net photosynthesis. Twelve contrasting rice genotypes responded differentially to As(V) stress. Present study evaluated As tolerant and sensitive rice cultivars with respect to As(V) imposed alterations in pigments content, photosynthetic attributes along with sugar metabolism. Starch contents, the principle carbohydrate storage declined differentially among As(V) stressed test cultivars, being more pronounced in cvs. Swarnadhan, Tulaipanji, Pusa basmati, Badshabhog, Tulsibhog and IR-20 compared to cvs. Bhutmuri, Kumargore, Binni, Vijaya, TN-1 and IR-64. Therefore, the six former cultivars tried to adapt defensive mechanisms by accumulating higher levels of reducing and non-reducing sugars to carry out basal metabolism to withstand As(V) induced alterations in photosynthesis. This study could help to screen As tolerant and sensitive rice genotypes based on their photosynthetic efficiency in As polluted agricultural fields to reduce As contamination assisted ecotoxicological risk.


Assuntos
Arseniatos/efeitos adversos , Metabolismo dos Carboidratos/efeitos dos fármacos , Oryza/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Poluentes do Solo/efeitos adversos , Genótipo , Oryza/genética , Oryza/fisiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Estresse Fisiológico
20.
Ecotoxicol Environ Saf ; 201: 110822, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32534334

RESUMO

Boron (B) toxicity is an important abiotic constraint that limits crop productivity mainly in arid and semi-arid areas of the world. High levels of B in soil disturbs several physiological and biochemical processes in plant. The aim of this study was to investigate the function of melatonin (Mel) in the regulation of carbohydrate and proline (Pro) metabolism, photosynthesis process and antioxidant system of wheat seedlings under B toxicity conditions. High levels of B inhibited net photosynthetic rate (PN), stomatal conductance (gs), content of chlorophyll (Chl) a, b, δ-aminolevulinic acid (δ-ALA), nitrogen (N) and phosphorus (P), and increased accumulation of B, Chl degradation and activity of chlorophyllase (Chlase; a Chl degrading enzyme), and downregulated the activity of enzymes (δ-ALAD; δ-aminolevulinic acid dehydratase) involved in the biosynthesis of photosynthesis pigments, photosynthesis (carbonic anhydrase and ribulose-1,5-bisphosphate carboxylase/oxygenase) and carbohydrate metabolism (cell wall invertase, CWI) in wheat seedlings. Also, high levels of B caused oxidative damage by increasing the content of malondialdehyde, superoxide anion and H2O2, and activity of glycolate oxidase (an H2O2-producing enzyme) in leaves of seedlings. However, foliar application of Mel significantly improved photosynthetic pigments concentration by increasing δ-ALA, δ-ALAD and decreasing Chl degradation and Chlase activity and led to an increase of plant growth attributes under both B toxicity and non-toxicity conditions. Under normal and B toxicity conditions, exogenous Mel also improved content of N, P, total soluble carbohydrates (TSCs) and Pro, and upregulated activity of CWI and Δ1-pyrroline-5-carboxylate synthetase. Mel significantly suppressed the adverse effects of excess B by alleviating cellular oxidative damage through enhanced reactive oxygen species scavenging by superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and lipoxygenase, and content of total phenolic compounds (TPC), ascorbate and reduced glutathione. These results postulate that Mel induced plant defense mechanisms by enhancing Pro, TSCs, TPC, nutrients (N and P) uptake and enzymatic and non-enzymatic antioxidants.


Assuntos
Antioxidantes/metabolismo , Boro/toxicidade , Melatonina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Metabolismo dos Carboidratos/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
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