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1.
Int J Mol Sci ; 22(17)2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34502129

RESUMO

Size control is a fundamental question in biology, showing incremental complexity in plants, whose cells possess a rigid cell wall. The phytohormone auxin is a vital growth regulator with central importance for differential growth control. Our results indicate that auxin-reliant growth programs affect the molecular complexity of xyloglucans, the major type of cell wall hemicellulose in eudicots. Auxin-dependent induction and repression of growth coincide with reduced and enhanced molecular complexity of xyloglucans, respectively. In agreement with a proposed function in growth control, genetic interference with xyloglucan side decorations distinctly modulates auxin-dependent differential growth rates. Our work proposes that auxin-dependent growth programs have a spatially defined effect on xyloglucan's molecular structure, which in turn affects cell wall mechanics and specifies differential, gravitropic hypocotyl growth.


Assuntos
Glucanos/metabolismo , Ácidos Indolacéticos/metabolismo , Células Vegetais/metabolismo , Desenvolvimento Vegetal , Fenômenos Fisiológicos Vegetais , Xilanos/metabolismo , Arabidopsis/fisiologia , Parede Celular/metabolismo , Imunofluorescência , Regulação da Expressão Gênica de Plantas , Glucanos/química , Ervilhas/fisiologia , Transdução de Sinais , Xilanos/química
2.
Biochemistry (Mosc) ; 86(7): 878-886, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34284711

RESUMO

The effects of superoxide dismutase (SOD) inhibitors, diethyldithiocarbamate (DDC), triethylenetetramine (trien), and their combination with glucose on cells of the epidermis from pea leaves of different age (rapidly growing young leaves and slowly growing old leaves) was investigated. DDC and trien caused death of the guard cells as determined by destruction of their nuclei. Glucose did not affect destruction of the nuclei induced by SOD inhibitors in the cells from old leaves, but intensified it in the cells from young leaves. 2-Deoxyglucose, an inhibitor of glycolysis, and propyl gallate, SOD-mimic and antioxidant, suppressed destruction of the nuclei that was caused by SOD inhibitors and glucose in cells of the epidermis from the young, but not from the old leaves. Glucose and trien stimulated, and propyl gallate reduced generation of reactive oxygen species (ROS) in the pea epidermis as determined by the fluorescence of 2',7'-dichlorofluorescein (DCF). Carbonyl cyanide m-chlorophenylhydrazone (CCCP), a protonophoric uncoupler of oxidative and photosynthetic phosphorylation, suppressed the DCF fluorescence in the guard cells. Treatment of the cells with CCCP followed by its removal with washing increased destruction of the nuclei caused by SOD inhibitors and glucose. In young leaves, CCCP was less effective than in old ones. The findings demonstrate the effects of SOD inhibitors and glucose on the cell death and generation of ROS and could indicate glycolysis-dependent ROS production.


Assuntos
Ditiocarb/farmacologia , Glucose/metabolismo , Ervilhas/efeitos dos fármacos , Epiderme Vegetal/efeitos dos fármacos , Espécies Reativas de Oxigênio , Superóxido Dismutase/antagonistas & inibidores , Trientina/farmacologia , Morte Celular , Quelantes/farmacologia , Inibidores Enzimáticos/farmacologia , Glucose/farmacologia , Ervilhas/enzimologia , Ervilhas/metabolismo , Ervilhas/fisiologia , Epiderme Vegetal/enzimologia , Epiderme Vegetal/metabolismo , Epiderme Vegetal/fisiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia
3.
Int J Mol Sci ; 22(9)2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-34063012

RESUMO

Single-walled carbon nanotubes (SWCNTs) emerge as promising novel carbon-based nanoparticles for use in biomedicine, pharmacology and precision agriculture. They were shown to penetrate cell walls and membranes and to physically interact and exchange electrons with photosynthetic complexes in vitro. Here, for the first time, we studied the concentration-dependent effect of foliar application of copolymer-grafted SWCNTs on the structural and functional characteristics of intact pea plants. The lowest used concentration of 10 mg L-1 did not cause any harmful effects on the studied leaf characteristics, while abundant epicuticular wax generation on both leaf surfaces was observed after 300 mg L-1 treatment. Swelling of both the granal and the stromal regions of thylakoid membranes was detected after application of 100 mg L-1 and was most pronounced after 300 mg L-1. Higher SWCNT doses lead to impaired photosynthesis in terms of lower proton motive force generation, slower generation of non-photochemical quenching and reduced zeaxanthin content; however, the photosystem II function was largely preserved. Our results clearly indicate that SWCNTs affect the photosynthetic apparatus in a concentration-dependent manner. Low doses (10 mg L-1) of SWCNTs appear to be a safe suitable object for future development of nanocarriers for substances that are beneficial for plant growth.


Assuntos
Cloroplastos/ultraestrutura , Nanotubos de Carbono/química , Ervilhas/fisiologia , Ervilhas/ultraestrutura , Fotossíntese , Folhas de Planta/anatomia & histologia , Dióxido de Carbono/metabolismo , Carotenoides/metabolismo , Permeabilidade da Membrana Celular , Clorofila/metabolismo , Fluorescência , Nanotubos de Carbono/ultraestrutura , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/ultraestrutura , Prótons , Tilacoides/metabolismo , Fatores de Tempo , Xantofilas/metabolismo
4.
Cells ; 10(4)2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33923901

RESUMO

The accumulation of proline is one of the defense mechanisms of plants against the harmful effects of adverse environmental conditions; however, when pea plants were treated for 12 h with CdCl2, the proline concentration decreased in the youngest A (not expanded) and B1 (expanded) leaves, and did not change significantly in the B2 (mature, expanded) or C (the oldest) leaves. After 24 h of cadmium (Cd) stress, the proline concentration remained low in A and B1 leaves, while in B2 and C leaves, it increased, and after 48 h, an increase in the proline concentration in the leaves at each stage of development was observed. The role of proline in the different phases of plant response to the Cd treatment is discussed. Changes in proline accumulation corresponded closely with changes in the transcript levels of PsP5CS2, a gene encoding D1-pyrroline-5-carboxylate synthetase involved in proline synthesis, and PsPDH1, a gene encoding proline dehydrogenase engaged in proline degradation. CdCl2 application induced the expression of PsProT1 and PsProT2, genes encoding proline transporters, especially during the first 12 h of treatment in A and B1 leaves. When the time courses of abscisic acid (ABA) and proline accumulation were compared, it was concluded that an increase in the proline concentration in the leaves of Cd-treated pea plants was more related to a decrease in chlorophyll concentration (leaves B2 and C) and an increase in the malondialdehyde level (A and B1 leaves) than with an increase in ABA concentration alone. Exogenous application of ABA (0.5, 5, 50 µM) significantly increased the proline concentration in the A leaves of pea plants only, and was accompanied by an elevated and repressed expression of PsP5CS2 and PsPDH1 in these leaves, respectively. The presented results suggest that under Cd stress, the accumulation of proline in leaves of pea plants may take place independently of the ABA signaling.


Assuntos
Ácido Abscísico/farmacologia , Cádmio/toxicidade , Ervilhas/metabolismo , Ervilhas/fisiologia , Folhas de Planta/metabolismo , Prolina/metabolismo , Estresse Fisiológico , Sequência de Bases , Transporte Biológico/genética , Clorofila/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Malondialdeído/metabolismo , Ervilhas/efeitos dos fármacos , Ervilhas/genética , Folhas de Planta/efeitos dos fármacos , Prolina/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Estresse Fisiológico/efeitos dos fármacos
5.
Cells ; 10(1)2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33451018

RESUMO

Photosynthesis is an important target of action of numerous environmental factors; in particular, stressors can strongly affect photosynthetic light reactions. Considering relations of photosynthetic light reactions to electron and proton transport, it can be supposed that extremely low frequency magnetic field (ELFMF) may influence these reactions; however, this problem has been weakly investigated. In this paper, we experimentally tested a hypothesis about the potential influence of ELFMF of 18 µT intensity with Schumann resonance frequencies (7.8, 14.3, and 20.8 Hz) on photosynthetic light reactions in wheat and pea seedlings. It was shown that ELFMF decreased non-photochemical quenching in wheat and weakly influenced quantum yield of photosystem II at short-term treatment; in contrast, the changes in potential and effective quantum yields of photosystem II were observed mainly under chronic action of ELFMF. It is interesting that both short-term and chronic treatment decreased the time periods for 50% activation of quantum yield and non-photochemical quenching under illumination. Influence of ELFMF on pea was not observed at both short-term and chronic treatment. Thus, we showed that ELFMF with Schumann resonance frequencies could influence photosynthetic light processes; however, this effect depends on plant species (wheat or pea) and type of treatment (short-term or chronic).


Assuntos
Luz , Campos Magnéticos , Ervilhas/fisiologia , Ervilhas/efeitos da radiação , Fotossíntese/efeitos da radiação , Triticum/fisiologia , Triticum/efeitos da radiação , Complexo de Proteína do Fotossistema II/metabolismo , Teoria Quântica
6.
J Plant Physiol ; 256: 153314, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33197828

RESUMO

Four semi-leafless pea (Pisum sativum L.) cultivars at the vegetative stage of growth were exposed to progressive soil drought, which lasted for 18 days until the plants began to wilt, after which a 7-day period of the recovery from stress followed, when plant watering was resumed. The soil drought negatively affected plant growth, slowing down the rate of shoot elongation, decreasing the accumulation of fresh and dry weight, inhibiting the development of new leaves, and delaying the flowering of plants. Changes in the levels of 41 polar metabolites (identified by GC-MS) were established by the GC-FID method in the shoot tip, stem, stipules and tendrils, separately. Drought caused re-arrangement in the metabolism in all parts of the pea shoot, leading to a significant increase in the content of total polar metabolites. Although changes in most metabolites in the same parts of shoot were not identical among the pea cultivars studied, some metabolites were uniformly accumulated until 18th day of drought and decreased after recovery. They were i) proline and malate in all, while myo-inositol in most parts of shoot (of all the pea cultivars), ii) sucrose and glycine in the shoot tip, iii) homoserine in the stem and iv) GABA in stipules. These findings signify that the pea adjustment to progressive soil drought includes both accumulation of osmolytes and osmoprotectants and translocation of some of them (proline, sucrose, myo-inositol) to the shoot tip, thereby protecting the youngest tissues from damage caused by water deficit.


Assuntos
Desidratação/fisiopatologia , Secas , Ervilhas/genética , Ervilhas/metabolismo , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Água/metabolismo , Desidratação/genética , Variação Genética , Genótipo , Ervilhas/fisiologia
7.
Sci Rep ; 10(1): 18818, 2020 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-33139772

RESUMO

A polyhouse study was conducted to evaluate the relative effectiveness of different micronutrient fertilizer formulation and application methods on wheat, pea and canola, as indicated by yield response and fate of micronutrients in contrasting mineral soils. The underlying factors controlling micronutrient bioavailability in a soil-plant system were examined using chemical and spectroscopic speciation techniques. Application of Cu significantly improved grain and straw biomass yields of wheat on two of the five soils (Ukalta and Sceptre), of which the Ukalta soil was critically Cu deficient according to soil extraction with DTPA. The deficiency problem was corrected by either soil or foliar application of Cu fertilizers. There were no significant yield responses of pea to Zn fertilization on any of the five soils. For canola, soil placement of boric acid was effective in correcting the deficiency problem in Whitefox soil, while foliar application was not. Soil extractable Cu, Zn, and B concentration in post-harvest soils were increased with soil placement of fertilizers, indicating that following crops in rotation could benefit from this application method. The chemical and XANES spectroscopic speciation indicates that carbonate associated is the dominant form of Cu and Zn in prairie soils, where chemisorption to carbonates is likely the major process that determines the fate of added Cu and Zn fertilizer.


Assuntos
Brassica/fisiologia , Fertilizantes , Micronutrientes , Fenômenos Fisiológicos da Nutrição/fisiologia , Ervilhas/fisiologia , Fenômenos Fisiológicos Vegetais , Solo/química , Triticum/fisiologia , Boro/análise , Carbonatos , Cobre/análise , Micronutrientes/análise , Zinco/análise
8.
Chemosphere ; 258: 127411, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947668

RESUMO

Non-steroidal anti-inflammatory drugs as an important group of emerging environmental contaminants in irrigation water and soils can influence biochemical and physiological processes essential for growth and development in plants as non-target organisms. Plants are able to take up, transport, transform, and accumulate drugs in the roots. Root biomass in ten-days old pea plants was lowered by 6% already under 0.1 mg/L naproxen (NPX) due to a lowered number of lateral roots, although 0.5 mg/L NPX stimulated the total root length by 30% as against control. Higher section area (by 40%) in root tip, area of xylem (by 150%) or stele-to-section ratio (by 10%) in zone of maturation, and lower section area in zone of lateral roots (by 18%) prove the changes in primary root anatomy and its earlier differentiation at 10 mg/L NPX. Accumulated NPX (up to 10 µg/g DW at 10 mg/L) and products of its metabolization in roots increased the amounts of hydrogen peroxide (by 33%), and superoxide (by 62%), which was reflected in elevated lipid peroxidation (by 32%), disruption of membrane integrity (by 89%) and lowering both oxidoreductase and dehydrogenase activities (by up to 40%). Elevated antioxidant capacity (SOD, APX, and other molecules) under low treatments decreased at 10 mg/L NPX (both by approx. 30%). Naproxen was proved to cause changes at both cellular and tissue levels in roots, which was also reflected in their anatomy and morphology. Higher environmental loading through drugs thus can influence even the root function.


Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Naproxeno/toxicidade , Ervilhas/fisiologia , Antioxidantes/metabolismo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Estresse Oxidativo/efeitos dos fármacos , Ervilhas/efeitos dos fármacos , Raízes de Plantas
9.
Plant Sci ; 298: 110566, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32771167

RESUMO

Pisum fulvum is an annual legume native to Syria, Lebanon, Israel and Jordan. In certain locations, P. fulvum individuals were documented to display a reproductive dimorphism - amphicarpy, with both above and below ground flowers and pods. Herein we aimed to study the possible role of soil texture on amphicarpy in P. fulvum, to investigate the possible bio-climatic associations of P. fulvum amphicarpy and to identify genetic markers associated with this phenotype. A set of 127 germplasm accessions sampled across the Israeli distribution range of the species was phenotyped in two common garden nurseries. Land use and bioclimatic data were used to delineate the eco-geographic clustering of accession's sampling sites. Single nucleotide polymorphism (SNP) markers were employed in genome-wide association study to identify associated loci. Amphicarpy was subject to strong experimental site x genotype interaction with higher phenotypic expression in fine textured soil relative to sandy loam. Amphicarpy was more prevalent among accessions sampled in eastern Judea and Samaria and was weakly associated with early phenology and relatively modest above ground biomass production. Twelve SNP markers were significantly associated with amphicarpy, each explaining between 8 and 12 % of the phenotypic variation. In P. fulvum amphicarpy seems to be a polygenetic trait controlled by an array of genes that is likely to be affected by environmental stimuli. The probable selective advantage of the association between amphicarpy and early flowering is in line with its relative prevalence in drought prone territories subject to heavy grazing.


Assuntos
Clima , Interação Gene-Ambiente , Ervilhas/fisiologia , Polimorfismo de Nucleotídeo Único , Reprodução/fisiologia , Solo/química , Marcadores Genéticos , Estudo de Associação Genômica Ampla , Fenótipo , Reprodução/genética
10.
Ecotoxicol Environ Saf ; 201: 110778, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32480161

RESUMO

Field peas (Pisum sativum L.) are widely cultivated throughout the world as a cool season grain and forage crop. Boron (B) toxicity is caused by high B concentration in the soil or irrigation water, and is particularly problematic in medium or heavier textured soil types with moderate alkalinity and low annual rainfall. Previous studies have indicated that B-toxicity increases oxidative stress in plants, and B-tolerance has been considered an important target in field pea plant breeding programmes. Inducers of tolerance may be a promising alternative for plant breeding. Little research has been conducted on the combined use of silicon (Si) and salicylic acid (SA) to remediate B-toxicity in field peas. The present study revealed the physiological and biochemical plant responses of applying Si + SA under B-toxicity (15 mg B L-1) on two Brazilian field pea cultivars (Iapar 83 and BRS Forrageira). A semi-hydroponic experiment was conducted using a completely randomized factorial design (2 × 5): with two field pea cultivars and five treatments which were formed by individual and combined applications of Si and SA under B-toxicity plus a control (control, B, B + Si, B + SA, and B + Si + SA). Si (2 mmol L-1) was applied to plants in two forms (root and leaf), while for SA (36 µmol L-1) only foliar applications were applied. Our results demonstrated that the combined use of exogenous Si + SA in field peas increased tolerance to B-toxicity through an intensified antioxidant plant defence system, resulting in a better regulation of reactive oxygen species (ROS) production and degradation. It significantly increased total chlorophyll and carotenoids contents, the activities of major antioxidant enzymes, and reduced MDA and H2O2 contents, resulting in increased fresh shoot and total plant dry biomass. The application of Si + SA alleviated the inhibitory effects of boron toxicity in field peas, resulting in greater plant growth by preventing oxidative membrane damage through an increased tolerance to B-excess within the plant tissue. Therefore, the use of Si + SA is an important and sustainable strategy to alleviate B-toxicity in field pea cultivation.


Assuntos
Antioxidantes/metabolismo , Boro/toxicidade , Ervilhas/fisiologia , Ácido Salicílico/metabolismo , Silício/metabolismo , Poluentes do Solo/toxicidade , Brasil , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ervilhas/efeitos dos fármacos , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo
11.
Psychon Bull Rev ; 27(5): 966-973, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32542481

RESUMO

Speed-accuracy trade-off (SAT) is the tendency for decision speed to covary with decision accuracy. SAT is an inescapable property of aimed movements being present in a wide range of species, from insects to primates. An aspect that remains unsolved is whether SAT extends to plants' movement. Here, we tested this possibility by examining the swaying in circles of the tips of shoots exhibited by climbing plants (Pisum sativum L.) as they approach to grasp a potential support. In particular, by means of three-dimensional kinematical analysis, we investigated whether climbing plants scale movement velocity as a function of the difficulty to coil a support. Results showed that plants are able to process the properties of the support before contact and, similarly to animal species, strategically modulate movement velocity according to task difficulty.


Assuntos
Fenômenos Biomecânicos/fisiologia , Movimento/fisiologia , Ervilhas/fisiologia
12.
Plant Signal Behav ; 15(4): 1737786, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32149565

RESUMO

Electrical signals (ESs) can be induced by local action of stressors in plants; they influence numerous physiological processes (photosynthesis, transpiration, respiration, genes expression, synthesis of phytohormones, etc.) and, thereby, induce a systemic adaptation response. Development of optical methods of a remote sensing of this response can be important for agricultural and ecological monitoring. Preliminarily, we showed (Sukhova et al., Plant Sign Behav 2019; 14:e1610301) that burning-induced ESs induced changes in leaf reflectance at broad spectral bands (400-500, 500-600, 600-700, and 700-800 nm). The aims of the present work were (i) investigation of ESs influence on difference reflectance indices (RIs) calculated on the basis of these broad spectral bands and (ii) analysis of connection of the indices with water content in plants. Pea seedlings were investigated. ESs were induced by burning of the first mature leaf; ESs had high amplitudes in the second leaf and had low amplitudes in the fourth leaf. It was shown that ESs induced significant changes in RIs, which were calculated on basis of intensities of the reflected light at (i) 400-500 and 600-700 nm, (ii) 500-600 and 700-800 nm, and (iii) 600-700 and 700-800 nm. The effect was strong in the second leaf and weak in the fourth leaf; that is, the response was dependent on the magnitude of ESs. ESs-induced changes in RI were strongly connected with ESs-induced decrease of leaf water content which was estimated on basis of decrease of water index. Thus, broadband RIs can be used for revealing the ESs-induced systemic stress response in plants.


Assuntos
Fenômenos Eletrofisiológicos , Incêndios , Fenômenos Ópticos , Ervilhas/fisiologia , Folhas de Planta/fisiologia , Água/metabolismo , Fotossíntese
13.
PLoS One ; 15(2): e0228993, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053664

RESUMO

Bioirrigation has been defined as the transfer of hydraulically lifted water by a deep-rooted plant to a neighbouring shallow-rooted plant which cannot access deep soil moisture. In this study, we tested if facilitative effects of bioirrigation or the competition for water dominate the interaction of two intercropped plants-deep-rooted pigeon pea (PP) and shallow-rooted finger millet (FM) before and during a drought. Additionally, we tested how the presence of a common mycorrhizal network (CMN) affects the balance between facilitative (i.e. bioirrigation) and competitive interactions between two intercropping species. Our results show that PP can indeed promote the water relations of FM during a drought event. Specifically, stomatal conductance in FM controls dropped to low values of 27.1 to 33.6 mmol m-2s-1, while FM in intercropping treatments were able to maintain its stomatal conductance at 60 mmol m-2s-1. In addition, the presence of PP reduced the drought-induced foliar damage and mortality of FM. The observed facilitative effects of PP on FM were partially enhanced by the presence of a CMN. In contrast to the facilitative effects under drought, PP exerted strong competitive effects on FM before the onset of drought. This hindered growth and biomass production of FM when intercropped with PP, an effect that was even enhanced in the presence of a CMN. The results from our study thus indicate that in intercropping, deep-rooted plants may act as "bioirrigators" for shallow-rooted crops and that a CMN can promote these facilitative effects. However, the interspecific competition between the intercropped plants under conditions of abundant moisture supply can be strong and are enhanced by the presence of a CMN. In more general terms, our study shows that the extent by which the antagonistic effects of facilitation and competition are expressed in an intercropping system strongly depends on the availability of resources, which in the case of the present study was water and the presence of biotic interactions (i.e. the presence of a CMN).


Assuntos
Secas , Milhetes/fisiologia , Ervilhas/metabolismo , Ervilhas/fisiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Água/metabolismo , Biomassa , Milhetes/metabolismo
14.
J Plant Physiol ; 246-247: 153133, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32065920

RESUMO

Reports on the effect of nitric oxide (NO) or reactive oxygen species (ROS) on photosynthesis and respiration in leaf tissues are intriguing; therefore, the effects of exogenous addition of sodium nitroprusside (SNP, releases NO) or H2O2 on the photosynthetic O2 evolution and respiratory O2 uptake by mesophyll protoplasts in pea (Pisum sativum) were evaluated in the present study. Low concentrations of SNP or H2O2 were used to minimize nonspecific effects. The effects of NO or H2O2 on respiration and photosynthesis were different. The presence of NO decreased the rate of photosynthesis but caused a marginal stimulation of dark respiration. Conversely, externally administered H2O2 drastically decreased the rate of respiration but only slightly decreased photosynthesis. The PS I activity was more sensitive to NO than PS II. On the other hand, 100 µM H2O2 had no effect on the photochemical reactions of either PS I or PS II. The sensitivity of photosynthesis to antimycin A or SHAM (reflecting the interplay between chloroplasts and mitochondria) was not affected by NO. By contrast, H2O2 markedly decreased the sensitivity of photosynthesis to antimycin A and SHAM. It can be concluded that chloroplasts are the primary targets of NO, while mitochondria are the primary targets of ROS in plant cells. We propose that H2O2 can be an important signal to modulate the crosstalk between chloroplasts and mitochondria.


Assuntos
Peróxido de Hidrogênio/metabolismo , Óxido Nítrico/metabolismo , Nitroprussiato/metabolismo , Ervilhas/fisiologia , Fotossíntese , Espécies Reativas de Oxigênio/metabolismo , Peróxido de Hidrogênio/administração & dosagem , Células do Mesofilo/efeitos dos fármacos , Células do Mesofilo/fisiologia , Óxido Nítrico/administração & dosagem , Nitroprussiato/administração & dosagem , Ervilhas/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/fisiologia , Protoplastos/efeitos dos fármacos , Protoplastos/fisiologia , Espécies Reativas de Oxigênio/administração & dosagem
15.
Photosynth Res ; 146(1-3): 175-187, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32043219

RESUMO

The remote sensing of a plant's physiological state is a key problem of precision agriculture. The photochemical reflectance index (PRI), which is based on the intensities of the reflected light at 531 and 570 nm, is an important tool for the remote sensing of photosynthetic processes in plants. In particular, the PRI can be strongly connected with the non-photochemical quenching of chlorophyll fluorescence (NPQ) and the quantum yield of photosystem II (ФPSII); however, this connection is dependent on illumination, the intensity of stressor actions, the time scale of measurements, etc. The aim of the present work was to analyze the connection of PRI with the energy-dependent component of NPQ (NPQF) and ФPSII under heating and soil drought conditions. Pea, wheat, and pumpkin seedlings, which were grown under controlled conditions, were investigated. A PAM fluorometer Dual-PAM-100 and spectrometer S-100 were used for measurements of photosynthetic parameters and PRI, respectively. It was shown that heat stress increased the NPQF and the magnitude of light-induced changes in PRI (ΔPRI) and decreased ФPSII in pea seedlings. The decreased ФPSII and increased ΔPRI were observed in wheat after heating, but significant changes in NPQF were absent; the significant decrease in ФPSII was observed in pumpkin seedlings, while there were no significant changes in the other parameters. ΔPRI and NPQF after heating were significantly correlated. However, a significant correlation of the absolute values of PRI with photosynthetic parameters was absent. The soil drought increased NPQF and the magnitude of ΔPRI and decreased ФPSII in peas. ΔPRI was strongly correlated with photosynthetic parameters, but this correlation was absent for the absolute value of PRI. Thus, ΔPRI is strongly connected with the magnitude of NPQF and can be used as an estimator of this parameter.


Assuntos
Cucurbita/fisiologia , Ervilhas/fisiologia , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema II/metabolismo , Triticum/fisiologia , Secas , Resposta ao Choque Térmico , Solo/química
16.
Plant Cell Physiol ; 61(2): 403-415, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31693150

RESUMO

Although control of xylem ion loading is essential to confer salinity stress tolerance, specific details behind this process remain elusive. In this work, we compared the kinetics of xylem Na+ and K+ loading between two halophytes (Atriplex lentiformis and quinoa) and two glycophyte (pea and beans) species, to understand the mechanistic basis of the above process. Halophyte plants had high initial amounts of Na+ in the leaf, even when grown in the absence of the salt stress. This was matched by 7-fold higher xylem sap Na+ concentration compared with glycophyte plants. Upon salinity exposure, the xylem sap Na+ concentration increased rapidly but transiently in halophytes, while in glycophytes this increase was much delayed. Electrophysiological experiments using the microelectrode ion flux measuring technique showed that glycophyte plants tend to re-absorb Na+ back into the stele, thus reducing xylem Na+ load at the early stages of salinity exposure. The halophyte plants, however, were capable to release Na+ even in the presence of high Na+ concentrations in the xylem. The presence of hydrogen peroxide (H2O2) [mimicking NaCl stress-induced reactive oxygen species (ROS) accumulation in the root] caused a massive Na+ and Ca2+ uptake into the root stele, while triggering a substantial K+ efflux from the cytosol into apoplast in glycophyte but not halophytes species. The peak in H2O2 production was achieved faster in halophytes (30 min vs 4 h) and was attributed to the increased transcript levels of RbohE. Pharmacological data suggested that non-selective cation channels are unlikely to play a major role in ROS-mediated xylem Na+ loading.


Assuntos
Tolerância ao Sal/fisiologia , Plantas Tolerantes a Sal/fisiologia , Xilema/fisiologia , Atriplex/fisiologia , Chenopodium quinoa/fisiologia , Fenômenos Eletrofisiológicos , Fabaceae/fisiologia , Peróxido de Hidrogênio/metabolismo , Íons , Cinética , Ervilhas/fisiologia , Folhas de Planta , Raízes de Plantas/metabolismo , Potássio , Espécies Reativas de Oxigênio , Salinidade , Tolerância ao Sal/genética , Plantas Tolerantes a Sal/genética , Sódio , Transcriptoma
17.
Physiol Plant ; 168(2): 406-421, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31503325

RESUMO

In plants, investigation on heavy metal toxicity and its mitigation by nutrient elements have gained much attention. However, mechanism(s) associated with nutrients-mediated mitigation of metal toxicity remain elusive. In this study, we have investigated the role and interrelation of glutathione (GSH) and hydrogen sulfide (H2 S) in the regulation of hexavalent chromium [Cr(VI)] toxicity in tomato (Solanum lycopersicum), pea (Pisum sativum) and brinjal (Solanum melongena) seedlings, supplemented with additional sulfur (S). The results show that Cr(VI) significantly reduced growth, total chlorophyll and photosynthetic quantum yield of tomato, pea and brinjal seedlings which was accompanied by enhanced intracellular accumulation of Cr(VI) in roots. Moreover, Cr(VI) enhanced the generation of reactive oxygen species in the studied vegetables, while antioxidant defense system exhibited differential responses. However, additional supply of S alleviated Cr(VI) toxicity. Interestingly, addition of l-buthionine sulfoximine (BSO, a glutathione biosynthesis inhibitor) further increased Cr(VI) toxicity even in the presence of additional S but GSH addition reverses the effect of BSO. Under similar condition, endogenous H2 S, l-cysteine desulfhydrase (DES) activity and cysteine content did not significantly differ when compared to controls. Hydroxylamine (HA, an inhibitor of DES) also increased Cr(VI) toxicity even in the presence of additional S but sodium hydrosulfide (NaHS, an H2 S donor) reverses the effect of HA. Moreover, Cr(VI) toxicity amelioration by NaHS was reversed by the addition of hypotaurine (HT, an H2 S scavenger). Taken together, the results show that GSH which might be derived from supplied S is involved in the mitigation of Cr(VI) toxicity in which H2 S signaling preceded GSH biosynthesis.


Assuntos
Cromo/toxicidade , Glutationa/fisiologia , Sulfeto de Hidrogênio/metabolismo , Lycopersicon esculentum/fisiologia , Ervilhas/fisiologia , Solanum melongena/fisiologia , Lycopersicon esculentum/efeitos dos fármacos , Ervilhas/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/fisiologia , Solanum melongena/efeitos dos fármacos
18.
Plant Cell Environ ; 43(4): 1023-1035, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31884709

RESUMO

The cultivation of legumes shows promise for the development of sustainable agriculture, but yield instability remains one of the main obstacles for its adoption. Here, we tested whether the yield stability (i.e., resistance and resilience) of pea plants subjected to drought could be enhanced by soil microbial diversity. We used a dilution approach to manipulate the microbial diversity, with a genotype approach to distinguish the effect of symbionts from that of microbial diversity as a whole. We investigated the physiology of plants in response to drought when grown on a soil containing high or low level of microbial diversity. Plants grown under high microbial diversity displayed higher productivity and greater resilience after drought. Yield losses were mitigated by 15% on average in the presence of high soil microbial diversity at sowing. Our study provides proof of concept that the soil microbial community as a whole plays a key role for yield stability after drought even in plant species living in relationships with microbial symbionts. These results emphasize the need to restore soil biodiversity for sustainable crop management and climate change adaptation.


Assuntos
Fabaceae/fisiologia , Microbiologia do Solo , Biodiversidade , Desidratação , Fabaceae/crescimento & desenvolvimento , Ervilhas/crescimento & desenvolvimento , Ervilhas/fisiologia
19.
Sci Rep ; 9(1): 16570, 2019 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-31719580

RESUMO

Although plants are essentially sessile in nature, these organisms are very much in tune with their environment and are capable of a variety of movements. This may come as a surprise to many non-botanists, but not to Charles Darwin, who reported that plants do produce movements. Following Darwin's specific interest on climbing plants, this paper will focus on the attachment mechanisms by the tendrils. We draw attention to an unsolved problem in available literature: whether during the approach phase the tendrils of climbing plants consider the structure of the support they intend to grasp and plan the movement accordingly ahead of time. Here we report the first empirical evidence that this might be the case. The three-dimensional (3D) kinematic analysis of a climbing plant (Pisum sativum L.) demonstrates that the plant not only perceives the support, but it scales the kinematics of tendrils' aperture according to its thickness. When the same support is represented in two-dimensions (2D), and thus unclimbable, there is no evidence for such scaling. In these circumstances the tendrils' kinematics resemble those observed for the condition in which no support was offered. We discuss these data in light of the evidence suggesting that plants are equipped with sensory mechanisms able to provide the necessary information to plan and control a movement.


Assuntos
Ervilhas/fisiologia , Pontos de Referência Anatômicos , Fenômenos Biomecânicos , Movimento , Ervilhas/anatomia & histologia
20.
Planta ; 251(1): 11, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31776673

RESUMO

MAIN CONCLUSION: Components of the photosynthetic electron transport chain in pea (Pisum sativum L.) leaves under in vivo conditions showed the following sensitivity to the inhibitory action of chromium(VI): intersystem electron transport > photosystem I > photosystem II. Inhibitory effects of chromium (VI) (K2Cr2O7, Cr) on the light reactions of photosynthesis were studied in vivo in Pisum sativum L. by using Multi-function Plant Efficiency Analyser (M-PEA-2). Photosynthetic parameters related to photosystem (PS) II, PSI and intersystem electron carriers were calculated from the light-induced kinetics of prompt chlorophyll a fluorescence (OJIP transient), delayed chlorophyll a fluorescence (DF), and 820 nm modulated reflection (MR). We showed that the I2 step of DF induction is sensitive to inhibition of the Q0 site of the cytochrome b6f complex. Such parameters as δRo of the JIP test related to the functional state of photosynthetic reactions beyond the PQ pool, Vred of the MR induction assigned to the overall rate of P700+ and plastocyanin reduction, and I2 step of the DF induction were significantly altered in the presence of low-dose Cr(VI). Moderate doses of Cr affected mainly PSI-related parameters including Vox and ΔMR parameters of the MR induction, whereas high-dose treatment influenced JIP test parameters φPo(= FV/FM) and ψEo related to PSII. The obtained results showed that the earliest Cr(VI) effect on the photosynthetic electron transport chain manifests itself by inhibition of the intersystem electron transport, rather, at the level of the cytochrome b6f complex. Inhibitory effects of Cr on PSI were more pronounced than those on PSII. Sensitivity of the used kinetic parameters toward the functional state of photosynthetic reactions makes this approach suitable for early diagnostics of toxic action of pollutants on plants.


Assuntos
Cromo/farmacologia , Ervilhas/metabolismo , Fotossíntese/fisiologia , Clorofila A/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Transporte de Elétrons/fisiologia , Metais Pesados/metabolismo , Ervilhas/fisiologia , Fotossíntese/efeitos dos fármacos
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