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1.
Phytopathology ; 109(11): 1878-1887, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31241407

RESUMO

Root parasitic weeds in Orobanchaceae pose a tremendous threat to agriculture worldwide. We used an in vitro assay to screen libraries of small molecules for those capable of inhibiting or enhancing haustorium development in the parasitic plant Triphysaria versicolor. Several redox-modifying molecules and one structural analog of 2,6-dimethoxybenzoquine (DMBQ) inhibited haustorium development in the presence of the haustorium-inducing factor DMBQ, some of these without apparent growth inhibition to the root. Triphysaria seedlings were able to acclimate to some of these redox inhibitors. Transcript levels of four early-stage haustorium genes were differentially influenced by inhibitors. These novel haustorium inhibitors highlight the importance of redox cycling for haustorium development and suggest the potential of controlling parasitic weeds by interrupting early-stage redox-signaling pathways.


Assuntos
Regulação da Expressão Gênica de Plantas , Orobanchaceae , Estruturas Vegetais , Bibliotecas de Moléculas Pequenas , Benzoquinonas/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Orobanchaceae/efeitos dos fármacos , Orobanchaceae/genética , Oxirredução , Doenças das Plantas/prevenção & controle , Estruturas Vegetais/efeitos dos fármacos , Estruturas Vegetais/genética , Estruturas Vegetais/crescimento & desenvolvimento , Transdução de Sinais/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia
2.
Plant Biol (Stuttg) ; 21(2): 352-360, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30472775

RESUMO

This study aimed to examine the evidence of direct interaction among actin, myosin and phosphatidylinositol 3-kinase (PI3K) in the polarisation and formation of the tetraspore germ tube of Gelidium floridanum. After release, tetraspores were exposed to cytochalasin B, latrunculin B, LY294002 and BDM for a period of 6 h. In control samples, formation of the germ tube occurred after the experimental period, with cellulose formation and elongated chloroplasts moving through the tube region in the presence of F-actin. In the presence of cytochalasin B, an inhibitor of F-actin, latrunculin B, an inhibitor of G-actin, and BDM, a myosin inhibitor, tetraspores showed no formation of the germ tube or cellulose. Spherical-shaped chloroplasts were observed in the central region with a few F-actin filaments in the periphery of the cytoplasm. Tetraspores treated with LY294002, a PI3K inhibitor, showed no formation of the tube at the highest concentrations. Polarisation of cytoplasmic contents did not occur, only cellulose formation. It was concluded that F-actin directs the cell wall components and contributes to the maintenance of chloroplast shape and elongation during germ tube formation. PI3K plays a fundamental role in signalling for the asymmetric polarisation of F-actin. Thus, F-actin regulates the polarisation and germination processes of tetraspores of G. floridanum.


Assuntos
Citoesqueleto de Actina/metabolismo , Miosinas/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Rodófitas/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Parede Celular/metabolismo , Cloroplastos/metabolismo , Cromonas/farmacologia , Citocalasinas , Diacetil/análogos & derivados , Diacetil/farmacologia , Morfolinas/farmacologia , Estruturas Vegetais/crescimento & desenvolvimento , Estruturas Vegetais/metabolismo , Rodófitas/efeitos dos fármacos , Rodófitas/crescimento & desenvolvimento , Tiazolidinas/farmacologia
3.
Sci Rep ; 8(1): 12511, 2018 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-30131566

RESUMO

Rice grain number directly affects crop yield. Identifying alleles that improve panicle architecture would greatly aid the development of high-yield varieties. Here, we show that the quantitative trait locus qSrn7 contains rice FRIZZY PANICLE (FZP), a previously reported gene encoding an ERF transcription factor that promotes floral transition. Reduced expression of FZP in the reproductive stage increases the extent of higher order branching of the panicle, resulting in increased grain number. Genotype analysis of this gene in cultivars from the publicly available National Institute of Agrobiological Sciences (NIAS) Core Collection demonstrated that the extent of higher order branching, especially in the upper panicle, was increased in those cultivars carrying the FZP allele associated with qSrn7. Furthermore, chromosome segment substitution lines resulting from a cross between Koshihikari and Kasalath, the latter of which carries qSrn7/FZP, also showed that upper panicle higher order branching and grain yield were increased by qSrn7/FZP. Our findings indicate that qSrn7/FZP influences panicle branching pattern and is thus useful in the breeding of high-yield rice varieties.


Assuntos
Oryza/fisiologia , Locos de Características Quantitativas , Fatores de Transcrição/genética , Cromossomos de Plantas , Evolução Molecular , Regulação da Expressão Gênica de Plantas , Oryza/genética , Fenótipo , Proteínas de Plantas/genética , Estruturas Vegetais/genética , Estruturas Vegetais/crescimento & desenvolvimento , Reprodução
4.
Sci Rep ; 8(1): 10983, 2018 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-30030488

RESUMO

Secondary cell wall (SCW) deposition in Arabidopsis is regulated among others by NAC transcription factors, where SND1 chiefly initiates xylem fibre differentiation while VND6 controls metaxylem vessel SCW development, especially programmed cell death and wall patterning. The translational relevance of Arabidopsis SCW regulation theory and the utility of characterized transcription factors as modular synthetic biology tools for improving commercial fibre crops is unclear. We investigated inter-lineage gene activation dynamics for potential fibre and vessel differentiation regulators from the widely grown hardwood Eucalyptus grandis (Myrtales). EgrNAC26, a VND6 homolog, and EgrNAC61, an SND1 homolog, were transiently expressed in Arabidopsis mesophyll protoplasts in parallel to determine early and late (i.e. 7 and 14 hours post-transfection) gene targets. Surprisingly, across the time series EgrNAC26 activated only a subset of SCW-related transcription factors and biosynthetic genes activated by EgrNAC61, specializing instead in targeting vessel-specific wall pit and programmed cell death markers. Promoters of EgrNAC26 and EgrNAC61 both induced reporter gene expression in vessels of young Arabidopsis plants, with EgrNAC61 also conferring xylem- and cork cambium-preferential expression in Populus. Our results demonstrate partial conservation, with notable exceptions, of SND1 and VND6 homologs in Eucalyptus and a first report of cork cambium expression for EgrNAC61.


Assuntos
Arabidopsis/genética , Eucalyptus/genética , Estruturas Vegetais/crescimento & desenvolvimento , Fatores de Transcrição/farmacologia , Ativação Transcricional/efeitos dos fármacos , Xilema/crescimento & desenvolvimento , Proteínas de Arabidopsis , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Plantas/genética , Estruturas Vegetais/genética , Homologia de Sequência de Aminoácidos , Fatores de Tempo , Xilema/genética
5.
Homeopathy ; 106(3): 145-154, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28844287

RESUMO

BACKGROUND: A previous study reported a significant statistical interaction between experiment date and treatment effect of Argentum nitricum 14x-30x on the growth rate of duckweed (Lemna gibba L.). The aim of the present study was to investigate the stability of the test system and intra-laboratory reproducibility of the effects found. METHODS: Duckweed was treated with A. nitricum potencies (14x-30x) as well as succussed and unsuccussed water controls. The outcome parameter area-related growth rate for day 0-7 was determined by a computerised image analysis system in two series of independent randomised and blinded experiments. Systematic negative control (SNC) experiments were carried out to investigate test system stability. Statistical analysis was performed with full two-way analysis of variance (ANOVA) and protected Fisher's Least Significant Difference (LSD) test. RESULTS: In the first repetition series we found a significant treatment effect (p = 0.016), while in the second series no effect was observed. The negative control experiments showed that the experimental system was stable. An a posteriori subgroup analysis concerning gibbosity revealed the importance of this growth state of L. gibba for successful reproduction of the statistically significant interaction in the original study; flat: no interaction (p = 0.762); slight gibbosity: no interaction (p = 0.356); medium gibbosity: significant interaction (p = 0.031), high gibbosity: highly significant interaction (p = 0.005). CONCLUSIONS: With the original study design (disregarding gibbosity status of L. gibba) results of the original study could not be reproduced sensu stricto. We conclude that the growth state gibbosity is crucial for successful reproduction of the original study. Different physiological states of the test organisms used for bioassays for homeopathic basic research must carefully be considered.


Assuntos
Araceae/efeitos dos fármacos , Sinergismo Farmacológico , Estruturas Vegetais/crescimento & desenvolvimento , Nitrato de Prata/farmacocinética , Análise de Variância , Humanos , Materia Medica/farmacocinética , Materia Medica/uso terapêutico , Reguladores de Crescimento de Planta/farmacologia , Reprodutibilidade dos Testes , Nitrato de Prata/administração & dosagem , Nitrato de Prata/uso terapêutico
6.
Ann Bot ; 119(4): 489-505, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28365757

RESUMO

Background: The origin of the Equisetum strobilus has long been debated and the fossil record has played an important role in these discussions. The paradigm underlying these debates has been the perspective of the shoot as node-internode alternation, with sporangiophores attached at nodes. However, fossils historically excluded from these discussions (e.g. Cruciaetheca and Peltotheca ) exhibit reproductive morphologies that suggest attachment of sporangiophores along internodes, challenging traditional views. This has rekindled discussions around the evolution of the Equisetum strobilus, but lack of mechanistic explanations has led discussions to a stalemate. Scope: A shift of focus from the node-internode view to a perspective emphasizing the phytomer as a modular unit of the shoot, frees the debate of homology constraints on the nature of the sporangiophore and inspires a mechanism-based hypothesis for the evolution of the strobilus. The hypothesis, drawing on data from developmental anatomy, regulatory mechanisms and the fossil record, rests on two tenets: (1) the equisetalean shoot grows by combined activity of the apical meristem, laying down the phytomer pattern, and intercalary meristems responsible for internode elongation; and (2) activation of reproductive growth programmes in the intercalary meristem produces sporangiophore whorls along internodes. Conclusions: Hierarchical expression of regulatory modules responsible for (1) transition to reproductive growth; (2) determinacy of apical growth; and (3) node-internode differentiation within phytomers, can explain reproductive morphologies illustrated by Cruciaetheca (module 1 only), Peltotheca (modules 1 and 2) and Equisetum (all three modules). This model has implications - testable by studies of the fossil record, phylogeny and development - for directionality in the evolution of reproductive morphology ( Cruciaetheca - Peltotheca - Equisetum ) and for the homology of the Equisetum stobilus. Furthermore, this model implies that sporangiophore development is independent of node-internode identity, suggesting that the sporangiophore represents the expression of an ancestral euphyllophyte developmental module that pre-dates the evolution of leaves.


Assuntos
Equisetum/anatomia & histologia , Evolução Biológica , Equisetum/crescimento & desenvolvimento , Fósseis/anatomia & histologia , Modelos Biológicos , Estruturas Vegetais/anatomia & histologia , Estruturas Vegetais/crescimento & desenvolvimento , Reprodução/fisiologia
7.
Plant Sci ; 256: 196-207, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28167033

RESUMO

Soil waterlogging events and high temperature conditions occur frequently in the Yangtze River Valley, yet the effects of these co-occurring stresses on fiber elongation have received little attention. In the current study, the combined effect of elevated temperature (ET) and soil waterlogging (SW) more negatively affected final fiber length (reduced by 5.4%-11.3%) than either stress alone by altering the composition of osmotically active solutes (sucrose, malate, and K+), where SW had the most pronounced effect. High temperature accelerated early fiber development, but limited the duration of elongation, thereby limiting final fiber length. Treatment of ET alone altered fiber sucrose content mainly through decreased source strength and the expression of the sucrose transporter gene GhSUT-1, making sucrose availability the primary determinant of final fiber length under ET. Waterlogging stress alone decreased source strength, down-regulated GhSUT-1 expression and enhanced SuSy catalytic activity for sucrose reduction. Waterlogging treatment alone also limited fiber malate production by down-regulating GhPEPC-1 & -2. However, combined elevated temperature and waterlogging limited primary cell wall synthesis by affecting GhCESAs genes and showed a negative impact on all three major osmotic solutes through the regulation of GhSUT-1, GhPEPC-1 & -2 and GhKT-1 expression and altered SuSy activity, which functioned together to produce a shorter fiber length.


Assuntos
Gossypium/metabolismo , Células Vegetais/fisiologia , Estruturas Vegetais/crescimento & desenvolvimento , Estresse Fisiológico , Temperatura Ambiente , Água , Parede Celular/metabolismo , Fibra de Algodão , Regulação para Baixo , Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas , Gossypium/crescimento & desenvolvimento , Malatos/metabolismo , Osmose , Estruturas Vegetais/citologia , Estruturas Vegetais/metabolismo , Potássio/metabolismo , Rios , Sementes/citologia , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Solo , Sacarose/metabolismo , Tricomas/citologia , Tricomas/crescimento & desenvolvimento , Tricomas/metabolismo
8.
Plant Sci ; 255: 72-81, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28131343

RESUMO

Ultraviolet-A radiation (UV-A: 315-400nm) is a component of solar radiation that exerts a wide range of physiological responses in plants. Currently, field attenuation experiments are the most reliable source of information on the effects of UV-A. Common plant responses to UV-A include both inhibitory and stimulatory effects on biomass accumulation and morphology. UV-A effects on biomass accumulation can differ from those on root: shoot ratio, and distinct responses are described for different leaf tissues. Inhibitory and enhancing effects of UV-A on photosynthesis are also analysed, as well as activation of photoprotective responses, including UV-absorbing pigments. UV-A-induced leaf flavonoids are highly compound-specific and species-dependent. Many of the effects on growth and development exerted by UV-A are distinct to those triggered by UV-B and vary considerably in terms of the direction the response takes. Such differences may reflect diverse UV-perception mechanisms with multiple photoreceptors operating in the UV-A range and/or variations in the experimental approaches used. This review highlights a role that various photoreceptors (UVR8, phototropins, phytochromes and cryptochromes) may play in plant responses to UV-A when dose, wavelength and other conditions are taken into account.


Assuntos
Embriófitas/efeitos da radiação , Fotorreceptores de Plantas/efeitos da radiação , Fotossíntese , Estruturas Vegetais/efeitos da radiação , Raios Ultravioleta , Biomassa , Embriófitas/crescimento & desenvolvimento , Embriófitas/metabolismo , Flavonoides/metabolismo , Fotorreceptores de Plantas/metabolismo , Pigmentos Biológicos/metabolismo , Estruturas Vegetais/crescimento & desenvolvimento , Estruturas Vegetais/metabolismo
9.
Plant J ; 89(1): 169-178, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27585732

RESUMO

Grain yield of the maize plant depends on the sizes, shapes, and numbers of ears and the kernels they bear. An automated pipeline that can measure these components of yield from easily-obtained digital images is needed to advance our understanding of this globally important crop. Here we present three custom algorithms designed to compute such yield components automatically from digital images acquired by a low-cost platform. One algorithm determines the average space each kernel occupies along the cob axis using a sliding-window Fourier transform analysis of image intensity features. A second counts individual kernels removed from ears, including those in clusters. A third measures each kernel's major and minor axis after a Bayesian analysis of contour points identifies the kernel tip. Dimensionless ear and kernel shape traits that may interrelate yield components are measured by principal components analysis of contour point sets. Increased objectivity and speed compared to typical manual methods are achieved without loss of accuracy as evidenced by high correlations with ground truth measurements and simulated data. Millimeter-scale differences among ear, cob, and kernel traits that ranged more than 2.5-fold across a diverse group of inbred maize lines were resolved. This system for measuring maize ear, cob, and kernel attributes is being used by multiple research groups as an automated Web service running on community high-throughput computing and distributed data storage infrastructure. Users may create their own workflow using the source code that is staged for download on a public repository.


Assuntos
Biologia Computacional/métodos , Processamento de Imagem Assistida por Computador/métodos , Estruturas Vegetais/anatomia & histologia , Zea mays/anatomia & histologia , Algoritmos , Produtos Agrícolas/anatomia & histologia , Estruturas Vegetais/crescimento & desenvolvimento , Análise de Componente Principal , Reprodutibilidade dos Testes , Zea mays/crescimento & desenvolvimento
10.
Acta Chim Slov ; 63(4): 738-746, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-28004101

RESUMO

Seed vigor is a complex physiological trait required to ensure the rapid and uniform emergence of plants in the field under different environmental conditions. Therefore, salicylic acid (SA, 0.5 mM) and calcium (Ca2+, 50 mM) priming were used as exogenous growth enhancers to stimulate wheat (Triticum durum Desf. cv. Yelken) seed vigor under high salinity. The main aim was to address whether priming of wheat with SA, Ca2+ and SA+Ca (SA, 0.5 mM + Ca2+, 50 mM; their combination) could bring about supplementary agronomic benefits particularly under stressful environments such as salinity. Exogenous application of SA or Ca2+ alone improved plant behavior in the presence of salinity stress. Nevertheless, the best results in terms of growth, seed vigor and total phenolic - flavonoids, chlorophyll - carotenoids contents and phenylalanine ammonia-lyase (PAL), ascorbic acide oxidase (AAO) activities and lipid peroxidation levels (LPO) were obtained in response to the combined SA+Ca treatment.


Assuntos
Cálcio/administração & dosagem , Lipídeos/análise , Fenóis/análise , Ácido Salicílico/administração & dosagem , Salinidade , Triticum/crescimento & desenvolvimento , Germinação , Estruturas Vegetais/crescimento & desenvolvimento , Triticum/química , Triticum/fisiologia
11.
Plant Physiol ; 168(4): 1590-602, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26077763

RESUMO

Xylem flow of water into fruits declines during fruit development, and the literature indicates a corresponding increase in hydraulic resistance in the pedicel. However, it is unknown how pedicel hydraulics change developmentally in relation to xylem anatomy and function. In this study on grape (Vitis vinifera), we determined pedicel hydraulic conductivity (kh) from pressure-flow relationships using hydrostatic and osmotic forces and investigated xylem anatomy and function using fluorescent light microscopy and x-ray computed microtomography. Hydrostatic kh (xylem pathway) was consistently 4 orders of magnitude greater than osmotic kh (intracellular pathway), but both declined before veraison by approximately 40% and substantially over fruit development. Hydrostatic kh declined most gradually for low (less than 0.08 MPa) pressures and for water inflow and outflow conditions. Specific kh (per xylem area) decreased in a similar fashion to kh despite substantial increases in xylem area. X-ray computed microtomography images provided direct evidence that losses in pedicel kh were associated with blockages in vessel elements, whereas air embolisms were negligible. However, vessel elements were interconnected and some remained continuous postveraison, suggesting that across the grape pedicel, a xylem pathway of reduced kh remains functional late into berry ripening.


Assuntos
Frutas/metabolismo , Vitis/metabolismo , Água/metabolismo , Microtomografia por Raio-X/métodos , Xilema/metabolismo , Transporte Biológico , Frutas/crescimento & desenvolvimento , Hidrodinâmica , Pressão Hidrostática , Modelos Anatômicos , Pressão Osmótica , Estruturas Vegetais/anatomia & histologia , Estruturas Vegetais/crescimento & desenvolvimento , Estruturas Vegetais/metabolismo , Vitis/anatomia & histologia , Vitis/crescimento & desenvolvimento , Xilema/anatomia & histologia
12.
Plant Biol (Stuttg) ; 17(6): 1218-26, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26012535

RESUMO

Plant growth-promoting rhizobacteria (PGPR) affect growth of host plants through various direct and indirect mechanisms. Three native PGPR (Pseudomonas putida) strains isolated from rhizospheric soil of a Mentha piperita (peppermint) crop field near Córdoba, Argentina, were characterised and screened in vitro for plant growth-promoting characteristics, such as indole-3-acetic acid (IAA) production, phosphate solubilisation and siderophore production, effects of direct inoculation on plant growth parameters (shoot fresh weight, root dry weight, leaf number, node number) and accumulation and composition of essential oils. Each of the three native strains was capable of phosphate solubilisation and IAA production. Only strain SJ04 produced siderophores. Plants directly inoculated with the native PGPR strains showed increased shoot fresh weight, glandular trichome number, ramification number and root dry weight in comparison with controls. The inoculated plants had increased essential oil yield (without alteration of essential oil composition) and biosynthesis of major essential oil components. Native strains of P. putida and other PGPR have clear potential as bio-inoculants for improving productivity of aromatic crop plants. There have been no comparative studies on the role of inoculation with native strains on plant growth and secondary metabolite production (specially monoterpenes). Native bacterial isolates are generally preferable for inoculation of crop plants because they are already adapted to the environment and have a competitive advantage over non-native strains.


Assuntos
Endófitos , Mentha piperita/crescimento & desenvolvimento , Óleos Voláteis/metabolismo , Estruturas Vegetais/crescimento & desenvolvimento , Pseudomonas , Microbiologia do Solo , Argentina , Endófitos/metabolismo , Ácidos Indolacéticos/metabolismo , Mentha piperita/metabolismo , Monoterpenos/metabolismo , Fosfatos/metabolismo , Desenvolvimento Vegetal , Estruturas Vegetais/metabolismo , Pseudomonas/metabolismo , Rizosfera , Sideróforos/metabolismo , Solo , Especificidade da Espécie
13.
Plant Signal Behav ; 10(3): e991566, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25658599

RESUMO

The common view that "plant cells cannot move relative to each other" is incorrect. Relative movement of plant cells relative to each other is expressed during fiber elongation, growth of arms of branched sclereids, intrusive growth of the tips of fusiform initials in the cambium, the increase in diameter of vessel members, growth in length of vessel-member elements in the secondary xylem of the few monocotyledons that express secondary growth, growth of laticifers, formation of tylosis, dilatation in the bark via parenchyma cell expansion, and growth of pollen tubes in the style. In all these cases, part of the plant cell remains in its original position, while other parts of the cell grow to the new locations, moving significantly relative to other cells. Not considering these movements will cause a delay in studying and understanding many aspects of differentiation of plant cells and tissues.


Assuntos
Movimento Celular , Células Vegetais/fisiologia , Desenvolvimento Vegetal , Estruturas Vegetais/citologia , Plantas , Arabidopsis/citologia , Arabidopsis/crescimento & desenvolvimento , Estruturas Vegetais/crescimento & desenvolvimento
14.
J Sci Food Agric ; 95(13): 2772-8, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25624024

RESUMO

BACKGROUND: We report investigations on the use of graphene quantum dots for growth enhancement in coriander (Coriandrum sativam L.) and garlic (Allium sativum) plants. The as-received seeds of coriander and garlic were treated with 0.2 mg mL(-1) of graphene quantum dots for 3 h before planting. RESULTS: Graphene quantum dots enhanced the growth rate in coriander and garlic plants, including leaves, roots, shoots, flowers and fruits, when the seeds were treated with graphene quantum dots. CONCLUSION: Our investigations open up the opportunity to use graphene quantum dots as plant growth regulators that can be used in a variety of other food plants for high yield.


Assuntos
Coriandrum/efeitos dos fármacos , Alho/efeitos dos fármacos , Grafite/farmacologia , Reguladores de Crescimento de Planta/farmacologia , Pontos Quânticos , Sementes/efeitos dos fármacos , Agricultura/métodos , Coriandrum/crescimento & desenvolvimento , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Alho/crescimento & desenvolvimento , Desenvolvimento Vegetal/efeitos dos fármacos , Estruturas Vegetais/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento
15.
Plant Sci ; 227: 157-64, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25219317

RESUMO

Micropropagation of Hypoxis hemerocallidea Fisch. and C.A. Mey was used as a model system to study the influence of cytokinins (CKs) on plant regeneration and biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in organ and callus cultures and their antioxidant activity. Fourteen free phenolic acids were detected using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) while antioxidant activity was evaluated using oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Cytokinins had a significant effect on the biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in H. hemerocallidea organ cultures. In particular, meta-topolin-treated organ cultures produced high concentrations of gallic, protocatechuic, gentisic, p-hydroxybenzoic, m-hydroxybenzoic, salicylic, chlorogenic and trans-cinnamic acids. The isoprenoid CK, N(6)-(2-isopentenyl)-adenine significantly increased the accumulation of hydroxycinnamic acid derivatives, namely, caffeic, p-coumaric, sinapic and ferulic acids. Cytokinin-treated organ cultures exhibited a significant increase in antioxidant activity, particularly in the ORAC model. In callus cultures, CKs decreased the concentrations of hydroxycinnamic acid derivatives and antioxidant activity when compared to the control. Overall, both CK type and concentration had a significant effect on plant regeneration, callus proliferation, biochemical accumulation of free phenolic acids and antioxidant activity of the resultant extracts.


Assuntos
Antioxidantes/metabolismo , Ácidos Cumáricos/metabolismo , Citocininas/farmacologia , Hidroxibenzoatos/metabolismo , Hypoxis/metabolismo , Fenóis/metabolismo , Reguladores de Crescimento de Planta/farmacologia , Antioxidantes/farmacologia , Compostos de Bifenilo/metabolismo , Ácidos Cumáricos/farmacologia , Hidroxibenzoatos/farmacologia , Hypoxis/crescimento & desenvolvimento , Isopenteniladenosina/farmacologia , Fenóis/farmacologia , Picratos/metabolismo , Técnicas de Embriogênese Somática de Plantas , Estruturas Vegetais/crescimento & desenvolvimento , Estruturas Vegetais/metabolismo , Regeneração
16.
Plant Sci ; 215-216: 134-40, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24388524

RESUMO

Chitooligosaccharides (COS) - water soluble derivatives from chitin, are an interesting group of molecules for several biological applications, for they can enter plant cells and bind negatively charged molecules. Several studies reported an enhanced plant growth and higher crop yield due to chitosan application in soil grown plants, but no studies have looked on the effect of COS application on plant mineral nutrient dynamics in hydroponically grown plants. In this study, Phaseolus vulgaris was grown in hydroponic culture and the effect of three different concentrations of COS on plant growth and mineral accumulation was assessed. There were significant changes in mineral allocations for Mo, B, Zn, P, Pb, Cd, Mn, Fe, Mg, Ca, Cu, Na, Al and K among treatments. Plant morphology was severely affected in high doses of COS, as well as lignin concentration in the stem and the leaves, but not in the roots. Chlorophyll A, B and carotenoid concentrations did not change significantly among treatments, suggesting that even at higher concentrations, COS application did not affect photosynthetic pigment accumulation. Plants grown at high COS levels had shorter shoots and roots, suggesting that COS can be phytotoxic to the plant. The present study is the first detailed report on the effect of COS application on mineral nutrition in plants, and opens the door for future studies that aim at utilizing COS in biofortification or phytoremediation programs.


Assuntos
Quitosana/farmacologia , Metais Pesados/metabolismo , Minerais/metabolismo , Oligossacarídeos/farmacologia , Phaseolus/efeitos dos fármacos , Estruturas Vegetais/efeitos dos fármacos , Oligoelementos/metabolismo , Carotenoides/metabolismo , Clorofila/metabolismo , Hidroponia , Lignina/metabolismo , Phaseolus/crescimento & desenvolvimento , Phaseolus/fisiologia , Fotossíntese/efeitos dos fármacos , Estruturas Vegetais/crescimento & desenvolvimento , Estruturas Vegetais/metabolismo
18.
Plant Biol (Stuttg) ; 16(2): 440-50, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24033882

RESUMO

This study evaluated effects of foliar spraying 24-epibrassinoide (24-EBL) on the growth of salt-stressed canola. Seedlings at the four-leaf stage were treated with 150 mM NaCl and different concentrations of 24-EBL (10(-6), 10(-8), 10(-10), 10(-12) M) for 15 days. A concentration of 10(-10) M 24-EBL was chosen as optimal and used in a subsequent experiment on plant biomass and leaf water potential parameters. The results showed that 24-EBL mainly promoted shoot growth of salt-stressed plants and also ameliorated leaf water status. Foliar spraying of salt-stressed canola with 24-EBL increased osmotic adjustment ability in all organs, especially in younger leaves and roots. This was mainly due to an increase of free amino acid content in upper leaves, soluble sugars in middle leaves, organic acids and proline in lower leaves, all of these compounds in roots, as well as essential inorganic ions. Na(+) and Cl(-) sharply increased in different organs under salt stress, and 24-EBL reduced their accumulation. 24-EBL improved the uptake of K(+), Ca(2+), Mg(2+) and NO3(-) in roots, which were mainly transported to upper leaves, while NO3(-) was mainly transported to middle leaves. Thus, 24-EBL improvements in ion homeostasis of K(+)/Na(+), Ca(2+)/Na(+), Mg(2+)/Na(+) and NO3(-)/Cl(-), especially in younger leaves and roots, could be explained. As most important parts, younger leaves and roots were the main organs protected by 24-EBL via improvement in osmotic adjustment ability and ion homeostasis. Further, physiological status of growth of salt-stressed canola was ameliorated after 24-EBL treatment.


Assuntos
Brassica napus/efeitos dos fármacos , Brassinosteroides/farmacologia , Íons/metabolismo , Osmose/efeitos dos fármacos , Pressão Osmótica/efeitos dos fármacos , Tolerância ao Sal/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Esteroides Heterocíclicos/farmacologia , Biomassa , Brassica napus/crescimento & desenvolvimento , Brassica napus/metabolismo , Brassinosteroides/metabolismo , Homeostase , Reguladores de Crescimento de Planta/metabolismo , Reguladores de Crescimento de Planta/farmacologia , Estruturas Vegetais/efeitos dos fármacos , Estruturas Vegetais/crescimento & desenvolvimento , Estruturas Vegetais/metabolismo , Sais , Sódio/metabolismo , Sódio/farmacologia , Cloreto de Sódio/metabolismo , Esteroides Heterocíclicos/metabolismo , Estresse Fisiológico , Água
19.
Plant Biol (Stuttg) ; 16(2): 428-39, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23944972

RESUMO

We have isolated a severe dwarf mutant derived from a Ds (Dissociation) insertion mutant rice (Oryza sativa var. japonica c.v. Dongjin). This severe dwarf phenotype, has short and dark green leaves, reduced shoot growth early in the seedling stage, and later severe dwarfism with failure to initiate flowering. When treated with bioactive GA3 , mutants are restored to the normal wild-type phenotype. Reverse transcription PCR analyses of 22 candidate genes related to the gibberellin (GA) biosynthesis pathway revealed that among 22 candidate genes tested, a dwarf mutant transcript was not expressed only in one OsKS2 gene. Genetic analysis revealed that the severe dwarf phenotype was controlled by recessive mutation of a single nuclear gene. The putative OsKS2 gene was a chromosome 4-located ent-kaurene synthase (KS), encoding the enzyme that catalyses an early step of the GA biosynthesis pathway. Sequence analysis revealed that osks2 carried a 1-bp deletion in the ORF region of OsKS2, which led to a loss-of-function mutation. The expression pattern of OsKS2 in wild-type cv Dongjin, showed that it is expressed in all organs, most prominently in the stem and floral organs. Morphological characteristics of the dwarf mutant showed dramatic modifications in internal structure and external morphology. We propose that dwarfism in this mutant is caused by a point mutation in OsKS2, which plays a significant role in growth and development of higher plants. Further investigation on OsKS2 and other OsKS-like proteins is underway and may yield better understanding of the putative role of OsKS in severe dwarf mutants.


Assuntos
Genes de Plantas , Giberelinas/genética , Oryza/genética , Fenótipo , Proteínas de Plantas/genética , Estruturas Vegetais/metabolismo , Deleção de Sequência , Alquil e Aril Transferases/genética , Alquil e Aril Transferases/metabolismo , Sequência de Aminoácidos , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Giberelinas/biossíntese , Dados de Sequência Molecular , Oryza/enzimologia , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Filogenia , Proteínas de Plantas/metabolismo , Estruturas Vegetais/enzimologia , Estruturas Vegetais/crescimento & desenvolvimento , Homologia de Sequência de Aminoácidos
20.
PLoS One ; 8(10): e78196, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24205154

RESUMO

The grain weight of wheat is strongly influenced by filling. Polyamines (PA) are involved in regulating plant growth. However, the effects of PA on wheat grain filling and its mechanism of action are unclear. The objective of the present study was to investigate the relationship between PAs and hormones in the regulation of wheat grain filling. Three PAs, spermidine (Spd), spermine (Spm), and putrescine (Put), were exogenously applied, and the grain filling characteristics and changes in endogenous PA and hormones, i.e., indole-3-acetic acid (IAA), zeatin (Z) + zeatin riboside (ZR), abscisic acid (ABA), ethylene (ETH) and gibberellin 1+4 (GAs), were quantified during wheat grain filling. Exogenous applications of Spd and Spm significantly increased the grain filling rate and weight, but exogenous Put had no significant effects on these measures. Exogenous Spd and Spm significantly increased the endogenous Spd, Spm, Z+ZR, ABA, and IAA contents and significantly decreased ETH evolution in grains. The endogenous Spd, Spm and Z+ZR contents were positively and significantly correlated with the grain filling rate and weight of wheat, and the endogenous ETH evolution was negatively and significantly correlated with the wheat grain filling rate and weight. Based upon these results, we concluded that PAs were involved in the balance of hormones that regulated the grain filling of wheat.


Assuntos
Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Estruturas Vegetais/crescimento & desenvolvimento , Poliaminas/metabolismo , Triticum/crescimento & desenvolvimento , Triticum/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Estruturas Vegetais/metabolismo , Putrescina/metabolismo , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Espermidina/metabolismo , Espermina/metabolismo
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