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1.
BMC Plant Biol ; 21(1): 477, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34670492

RESUMO

BACKGROUND: Both underground rhizomes/buds and above-ground Moso bamboo (Phyllostachys heterocycla) shoots/culms/branches are connected together into a close inter-connecting system in which nutrients are transported and shared among each organ. However, the starch storage and utilization mechanisms during bamboo shoot growth remain unclear. This study aimed to reveal in which organs starch was stored, how carbohydrates were transformed among each organ, and how the expression of key genes was regulated during bamboo shoot growth and developmental stages which should lay a foundation for developing new theoretical techniques for bamboo cultivation. RESULTS: Based on changes of the NSC content, starch metabolism-related enzyme activity and gene expression from S0 to S3, we observed that starch grains were mainly elliptical in shape and proliferated through budding and constriction. Content of both soluble sugar and starch in bamboo shoot peaked at S0, in which the former decreased gradually, and the latter initially decreased and then increased as shoots grew. Starch synthesis-related enzymes (AGPase, GBSS and SBE) and starch hydrolase (α-amylase and ß-amylase) activities exhibited the same dynamic change patterns as those of the starch content. From S0 to S3, the activity of starch synthesis-related enzyme and starch amylase in bamboo rhizome was significantly higher than that in bamboo shoot, while the NSC content in rhizomes was obviously lower than that in bamboo shoots. It was revealed by the comparative transcriptome analysis that the expression of starch synthesis-related enzyme-encoding genes were increased at S0, but reduced thereafter, with almost the same dynamic change tendency as the starch content and metabolism-related enzymes, especially during S0 and S1. It was revealed by the gene interaction analysis that AGPase and SBE were core genes for the starch and sucrose metabolism pathway. CONCLUSIONS: Bamboo shoots were the main organ in which starch was stored, while bamboo rhizome should be mainly functioned as a carbohydrate transportation channel and the second carbohydrate sink. Starch metabolism-related genes were expressed at the transcriptional level during underground growth, but at the post-transcriptional level during above-ground growth. It may be possible to enhance edible bamboo shoot quality for an alternative starch source through genetic engineering.


Assuntos
Metabolismo dos Carboidratos/genética , Proteínas de Plantas/metabolismo , Poaceae/genética , Amido/metabolismo , Transcriptoma , Enzima Ramificadora de 1,4-alfa-Glucana/genética , Enzima Ramificadora de 1,4-alfa-Glucana/metabolismo , Amilases/genética , Amilases/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/fisiologia , Brotos de Planta/ultraestrutura , Poaceae/crescimento & desenvolvimento , Poaceae/fisiologia , Poaceae/ultraestrutura , Rizoma/genética , Rizoma/crescimento & desenvolvimento , Rizoma/fisiologia , Rizoma/ultraestrutura
2.
Sci Rep ; 11(1): 9661, 2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-33958620

RESUMO

Somatic embryogenesis (SE) is the most important plant biotechnology process for plant regeneration, propagation, genetic transformation and genome editing of coffee, Coffea arabica L. Somatic embryo (SEs) conversion to plantlets is the principal bottleneck for basic and applied use of this process. In this study we focus on the maturation of SEs of C. arabica var. Typica. SEs conversion to plantlet up to 95.9% was achieved under osmotic stress, using 9 g/L gelrite, as compared with only 39.34% in non-osmotic stress. Mature SEs induced in osmotic stress developed shoot and root apical meristems, while untreated SEs were unable to do it. C. arabica regenerated plants from osmotic stress were robust, with higher leaf and root area and internode length. To understand a possible regulatory mechanism, gene expression of key genes of C. arabica, homologous to sequences in the Arabidopsis thaliana genome, were analyzed. A set of two component system and cytokinin signaling-related coding genes (AHK1, AHK3, AHP4 and ARR1) which interact with WUSCHEL and WOX5 homedomains and morphogenic genes, BABY-BOOM, LEC1, FUS3 and AGL15, underwent significant changes during maturation of SEs of C. arabica var. Typica. This protocol is currently being applied in genetic transformation with high rate of success.


Assuntos
Coffea/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Pressão Osmótica , Raízes de Plantas/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Coffea/embriologia , Coffea/ultraestrutura , Meristema/ultraestrutura , Pressão Osmótica/fisiologia , Raízes de Plantas/ultraestrutura , Brotos de Planta/ultraestrutura , Sementes/ultraestrutura , Transcriptoma
3.
Plant Sci ; 303: 110770, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33487354

RESUMO

Dodder is a holoparasitic flowering plant that re-establishes parasitism with the host when broken off from the host. However, how in vitro dodder shoots recycle stored nutrients to maintain growth for reparasitizing hosts is not well characterized. Here, the spatial and temporal distribution characteristics of carbohydrates and reactive oxygen species (ROS) were analysed to explore the mechanism of recycling stored nutrients in dodder shoots in vitro. Our results showed that in vitro dodder shoots grew actively for more than 10 d, while dry mass decreased continuously. During this process, the transcript levels and activities of amylases gradually increased until 2 d and then declined in basal stems, which induced starch degradation at the tissue, cellular and subcellular levels. Additionally, the distribution characteristics of H2O2 and the activities and transcript levels of antioxidant enzymes indicated that shoot tips exhibited more robust ROS-scavenging capacity, and basal stems maintained higher ROS accumulation. Comparative proteomics analysis revealed that starch in basal stems acted as an energy source, and the glycolysis, TCA cycle and pentose phosphate pathway represented the energy supply for shoot tip elongation with time. These results indicated that efficient nutrient recycling and ROS modulation facilitated the parasitism of dodder grown in vitro by promoting shoot elongation growth to reach the host.


Assuntos
Antioxidantes/metabolismo , Carbono/metabolismo , Cuscuta/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento , Metabolismo dos Carboidratos , Cuscuta/metabolismo , Cuscuta/ultraestrutura , Microscopia Eletrônica de Transmissão , Brotos de Planta/metabolismo , Brotos de Planta/ultraestrutura , Proteômica , Espécies Reativas de Oxigênio/metabolismo
4.
Sci Rep ; 10(1): 17569, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33067571

RESUMO

Silver nanoparticles (AgNPs) are presently the most commonly generated engineered nanomaterials and are found in a wide range of agro-commercial products. The present study was designed to synthesize AgNPs biologically using Ochradenus arabicus leaves and investigate their effect on the morphophysiological properties of Maerua oblongifolia raised in vitro. Physicochemical methods (ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy were performed for characterization and for obtaining microphotographs of the AgNPs. Shoots of M. oblongifolia (2-3 cm) grown in Murashige and Skoog medium supplemented with different concentrations of AgNPs (0, 10, 20, 30, 40, or 50 mg L-1) were used. Following 6 weeks of in vitro shoot regeneration, the shoot number, shoot length, leaf number, fresh weight, dry weight, chlorophyll content, total protein, proline level, and antioxidant enzyme activities of the plants were quantified. We found that 20 mg L-1 AgNPs increased the shoot number, shoot length, fresh weight, dry weight, and chlorophyll content of the plants. The maximum total protein was recorded in plants that were administered the lowest dose of AgNPs (10 mg L-1), while high concentrations of AgNPs (40 and 50 mg L-1) increased the levels of proline and the enzymes superoxide dismutase and catalase. Our results indicate that green-synthesized AgNPs may be of agricultural and medicinal interest owing to their effects on plants in vitro.


Assuntos
Magnoliopsida/efeitos dos fármacos , Magnoliopsida/metabolismo , Nanopartículas Metálicas , Prata , Antioxidantes/análise , Catalase/análise , Clorofila/análise , Meios de Cultura , Química Verde , Técnicas In Vitro , Magnoliopsida/fisiologia , Microscopia Eletrônica , Tamanho do Órgão , Folhas de Planta/metabolismo , Proteínas de Plantas/análise , Brotos de Planta/química , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/ultraestrutura , Prolina/análise , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Superóxido Dismutase/análise
5.
Ecotoxicol Environ Saf ; 204: 111086, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32781345

RESUMO

In the present research, Silene vulgaris as a representative species growing on both unpolluted and heavy metal (HM) polluted terrains were used to identify ecotype-specific responses to metallic stress. Growth, cell ultrastructure and element accumulations were compared between non-metallicolous (NM), calamine (CAL) and serpentine (SER) specimens untreated with HMs and treated with Pb, Cd and Zn ions under in vitro conditions. Moreover, proteins' modifications related to their level, carbonylation and degradations via vacuolar proteases were verified and linked with potential mechanisms to cope with ions toxicity. Our experiment revealed diversified strategy of HM uptake in NM and both metallicolous ecotypes, in which antagonistic relationship of Zn and Pb/Cd ions provided survival benefits for the whole organism. Despite this similarity, growth rate and metabolic pathways induced in CAL and SER shoots varied significantly. Exposition to HMs in CAL culture led to drop in protein level by approximately 16% compared to the control. This parameter nearly correlated with the enhanced activity of proteases at pH 5.2 as well as possible glutamate changes to proline and reduced glutathione, resulting in intensified growth and first signs of cell senescence. In turn, SER shoots were characterized by growth retardation (to 53% of the control), although protein level and carbonylation were not modified, while a deeper insight into protein network showed its remodeling towards production of polyamines and 2-oxoglutarate delivered to the Krebs cycle. Contrary, an uncontrolled HM influx in NM shoots contributed to morpho-structural disorders accompanied by an increase activity of proteases involved in the degradation of oxidized proteins, what pointed to metal-induced autophagy. Taken together, S. vulgaris ecotypes respond to stress by triggering various mechanisms engaged their survival and/or death under HM treatment.


Assuntos
Cádmio/toxicidade , Chumbo/toxicidade , Proteínas de Plantas/metabolismo , Silene/efeitos dos fármacos , Poluentes do Solo/toxicidade , Zinco/toxicidade , Autofagia/efeitos dos fármacos , Bioacumulação/efeitos dos fármacos , Cádmio/metabolismo , Ecótipo , Glutationa/metabolismo , Chumbo/metabolismo , Modelos Teóricos , Estresse Oxidativo/efeitos dos fármacos , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Brotos de Planta/ultraestrutura , Silene/crescimento & desenvolvimento , Silene/metabolismo , Silene/ultraestrutura , Poluentes do Solo/metabolismo , Zinco/metabolismo
6.
Sci Rep ; 9(1): 10372, 2019 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-31316123

RESUMO

The impact of nanotechnology in the field of agricultural sciences creates the need to study in greater detail the effect of products offering nanoparticles for application in plant species of agricultural interest. The objective of this study was to determine the response of stevia (Stevia rebaudiana B.) in vitro to different concentrations of AgNPs (silver nanoparticles), as well as to characterize and identify their absorption, translocation and accumulation mechanisms. Nodal segments of stevia grown in MS medium supplemented with AgNPs (0,12.5, 25, 50,100 and 200 mg L-1) were used. After 30 days of in vitro shoot proliferation, the number of shoots per explant, shoot length, chlorophyll content, dry matter content and the metallic silver (Ag) content of the plants were quantified. In addition, characterization, transport and accumulation of silver nanoparticles were performed by microscopic analysis. AgNPs were shown to be present in epidermal stem cells, within vascular bundles and in intermembrane spaces. In leaves, they were observed in ribs and stomata. The current and future use of AgNPs in agricultural sciences opens up the possibility of studying their effects on different plant species.


Assuntos
Nanopartículas Metálicas , Prata/farmacologia , Stevia/metabolismo , Transporte Biológico , Clorofila/metabolismo , Relação Dose-Resposta a Droga , Ferro/metabolismo , Magnésio/metabolismo , Microscopia Eletrônica , Microscopia de Fluorescência , Nitrogênio/metabolismo , Tamanho da Partícula , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Brotos de Planta/ultraestrutura , Prata/administração & dosagem , Prata/metabolismo , Stevia/efeitos dos fármacos , Stevia/ultraestrutura , Técnicas de Cultura de Tecidos
7.
Methods Mol Biol ; 1992: 239-255, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31148043

RESUMO

Complex geometry of plant organs and various types of organ surface deformation, including growth or hygroscopic movements, can be analyzed using sequential replica method. It enables obtaining a time-lapse series of high resolution images visualizing details of the examined surface and provides data sufficient for detailed computation of parameters characterizing surface deformation and geometry. Series of molds, made in dental polymer, representing the examined surface are used to obtain casts in epoxy resin or nail polish replicas, which are ready for microscopic examination, while the structure itself remains intact. Images obtained from the epoxy casts in scanning electron microscopy can be further used for 3D reconstruction and computation of local geometry. The sequential replica method is a universal method and can be applied to image complex shapes of a range of structures, like meristems, flowers, leaves, scarious bracts, or trichomes. Different plant species growing in various conditions can be studied.


Assuntos
Arabidopsis/ultraestrutura , Microscopia Eletrônica de Varredura/métodos , Folhas de Planta/ultraestrutura , Brotos de Planta/ultraestrutura , Técnicas de Réplica/métodos , Arabidopsis/crescimento & desenvolvimento , Fenômenos Biomecânicos , Proliferação de Células , Meristema/crescimento & desenvolvimento , Meristema/ultraestrutura , Microscopia/métodos , Folhas de Planta/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento
8.
Methods Mol Biol ; 1992: 257-268, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31148044

RESUMO

Analysis of meristem shape and gene expression pattern has been conducted in many species over the past decades. Recent live imaging techniques have allowed for an unprecedented accumulation of data on the biology of meristematic cells, as well as a better understanding of the molecular and biophysical mechanisms behind shape changes in this tissue. Here we describe in detail how to prepare shoot apices of both Arabidopsis and tomato, in order to image them over time using a confocal microscope equipped with a long distance water-dipping lens.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Microscopia Confocal/métodos , Brotos de Planta/crescimento & desenvolvimento , Imagem com Lapso de Tempo/métodos , Arabidopsis/ultraestrutura , Meristema/ultraestrutura , Brotos de Planta/ultraestrutura
9.
Methods Mol Biol ; 1992: 269-290, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31148045

RESUMO

Confocal microscopy is widely used to live-image plant tissue. Cell outlines can be visualized using fluorescent probes that mark the cell wall or plasma membrane, enabling the confocal microscope to be used as a 3D scanner with submicron precision. After imaging, the data needs to be analyzed by specialized software to quantify the features of interest, such as cell size and shape, growth rates and anisotropy, and gene expression. Here we present a protocol for the 3D image processing software MorphoGraphX ( www.MorphoGraphX.org ) using time-lapse images of an Arabidopsis thaliana sepal and the shoot apex of tomato.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Imageamento Tridimensional/métodos , Lycopersicon esculentum/crescimento & desenvolvimento , Microscopia Confocal/métodos , Arabidopsis/citologia , Arabidopsis/ultraestrutura , Proliferação de Células , Flores/citologia , Flores/crescimento & desenvolvimento , Flores/ultraestrutura , Lycopersicon esculentum/citologia , Lycopersicon esculentum/ultraestrutura , Desenvolvimento Vegetal , Brotos de Planta/citologia , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/ultraestrutura , Software
10.
Commun Biol ; 2: 134, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31044159

RESUMO

Shoot meristems, which harbor a small population of stem cells, are responsible for generating new above-ground organs in plants. The proliferation and differentiation of these stem cells is regulated by a genetic pathway involving two key meristematic genes: CLAVATA3 (CLV3) and WUSCHEL (WUS). However, it is not well understood how CLV3 and WUS expression domains in the shoot meristems are specified and maintained during post-embryogenic development. Here, we show that a tomato mutant with fasciated stems, flowers and fruits, due to impaired stem cell activity, is defective in a LITTLE ZIPPER gene denoted as DEFECTIVE TOMATO MERISTEM (DTM). DTM forms a negative feedback loop with class III homeodomain-leucine zipper (HD-ZIP III) transcription factors to confine CLV3 and WUS expression to specific domains of the shoot meristems. Our findings reveal a new layer of complexity in the regulation of plant stem cell homeostasis.


Assuntos
Regulação da Expressão Gênica de Plantas , Genes de Plantas , Lycopersicon esculentum/genética , Meristema/metabolismo , Mutação de Sentido Incorreto , Proteínas de Plantas/fisiologia , Sequência de Aminoácidos , Substituição de Aminoácidos , Proteínas de Arabidopsis/química , Sistemas CRISPR-Cas , Cruzamentos Genéticos , DNA de Plantas/genética , Retroalimentação Fisiológica , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Homeodomínio/fisiologia , Proteínas de Plantas/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Brotos de Planta/ultraestrutura , Ligação Proteica , Multimerização Proteica , Plântula/crescimento & desenvolvimento , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/fisiologia
11.
PLoS One ; 13(8): e0202324, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30133505

RESUMO

Induction of somatic embryogenesis and complete plantlet regeneration from callus culture of Hibiscus sabdariffa L. var. HS4288 has been made. Leaf and root explants were cultured on Murashige and Skoog (MS) and Driver-Kuniyuki Walnut (DKW) basal media supplemented with different concentrations of synthetic auxins and cytokinins. Root explants on DKW medium supplemented with 2.26µM 2, 4-Dichlorophenoxyacetic acid (2, 4-D) and 4.65µM kinetin (KIN) induced highest percentage (70%) of embryogenic calli. Average number of globular embryos per root derived callus produced within 6 weeks of culture initiation on MS media with different plant growth regulators (PGRs) ranged from 2.27±0.12 to 8.80±0.17 and that of cotyledonary embryos ranged from 0.00 to 2.53±0.20. On DKW medium comparatively more globular embryos (2.70±0.15 to 14.53±0.23) and cotyledonary embryos (0.00 to 8.90±0.17) were produced than that of MS medium. Regeneration of complete plantlets was highest (76.67%) when embryogenic calli with mature somatic embryos were grown on DKW medium containing 2.32µM KIN and 2.22µM 6-Benzyladenine (BA). Plants were primarily hardened in humidity, temperature and light controlled chamber and finally in a greenhouse showed 70% survival ability. Different stages of somatic embryogenesis process in the root derived embryogenic calli were elaborated in detail by morphological, histological and SEM study. The data were statistically analyzed by Duncan Multiple range test (p ≤ 0.05) and Principal component analysis (PCA). Flow cytometry and Inter-simple sequence repeats (ISSR) marker analysis confirmed that there was no genetic variation within the regenerated plants.


Assuntos
Hibiscus/crescimento & desenvolvimento , Hibiscus/genética , Técnicas de Embriogênese Somática de Plantas , Meios de Cultura , Citometria de Fluxo , Hibiscus/ultraestrutura , Microscopia Eletrônica de Varredura , Reguladores de Crescimento de Plantas , Raízes de Plantas , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/ultraestrutura , Sequências Repetitivas de Ácido Nucleico , Análise de Sequência de DNA
12.
Ann Bot ; 121(6): 1163-1172, 2018 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-29415162

RESUMO

Background and Aims: Setaria viridis is being promoted as a model C4 photosynthetic plant because it has a small genome (~515 Mb), a short life cycle (~60 d) and it can be transformed. Unlike other C4 grasses such as maize, however, there is very little information about how C4 leaf anatomy (Kranz anatomy) develops in S. viridis. As a foundation for future developmental genetic studies, we provide an anatomical and ultrastructural framework of early shoot development in S. viridis, focusing on the initiation of Kranz anatomy in seed leaves. Methods: Setaria viridis seeds were germinated and divided into five stages covering development from the dry seed (stage S0) to 36 h after germination (stage S4). Material at each of these stages was examined using conventional light, scanning and transmission electron microscopy. Key Results: Dry seeds contained three embryonic leaf primordia at different developmental stages (plastochron 1-3 primordia). The oldest (P3) leaf primordium possessed several procambial centres whereas P2 displayed only ground meristem. At the tip of P3 primordia at stage S4, C4 leaf anatomy typical of the malate dehydrogenase-dependent nicotinamide dinucleotide phosphate (NADP-ME) subtype was evident in that vascular bundles lacked a mestome layer and were surrounded by a single layer of bundle sheath cells that contained large, centrifugally located chloroplasts. Two to three mesophyll cells separated adjacent vascular bundles and one mesophyll cell layer on each of the abaxial and adaxial sides delimited vascular bundles from the epidermis. Conclusions: The morphological trajectory reported here provides a foundation for studies of gene regulation during early leaf development in S. viridis and a framework for comparative analyses with other C4 grasses.


Assuntos
Folhas de Planta/embriologia , Setaria (Planta)/embriologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Floema/ultraestrutura , Folhas de Planta/anatomia & histologia , Folhas de Planta/ultraestrutura , Brotos de Planta/anatomia & histologia , Brotos de Planta/embriologia , Brotos de Planta/ultraestrutura , Sementes/crescimento & desenvolvimento , Setaria (Planta)/anatomia & histologia , Setaria (Planta)/ultraestrutura , Xilema/ultraestrutura
13.
Nat Genet ; 49(7): 1082-1088, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28530677

RESUMO

Pigeonpea (Cajanus cajan), a tropical grain legume with low input requirements, is expected to continue to have an important role in supplying food and nutritional security in developing countries in Asia, Africa and the tropical Americas. From whole-genome resequencing of 292 Cajanus accessions encompassing breeding lines, landraces and wild species, we characterize genome-wide variation. On the basis of a scan for selective sweeps, we find several genomic regions that were likely targets of domestication and breeding. Using genome-wide association analysis, we identify associations between several candidate genes and agronomically important traits. Candidate genes for these traits in pigeonpea have sequence similarity to genes functionally characterized in other plants for flowering time control, seed development and pod dehiscence. Our findings will allow acceleration of genetic gains for key traits to improve yield and sustainability in pigeonpea.


Assuntos
Agricultura/métodos , Cajanus/genética , Genoma de Planta , África , Ásia , Cajanus/classificação , Cajanus/ultraestrutura , Clima , Comércio , DNA de Plantas/genética , Domesticação , Genes de Plantas , Variação Genética , Estudo de Associação Genômica Ampla , Tamanho do Órgão , Filogenia , Melhoramento Vegetal , Brotos de Planta/ultraestrutura , Polimorfismo de Nucleotídeo Único , Sementes , Análise de Sequência de DNA , América do Sul , Especificidade da Espécie
14.
Am J Bot ; 104(1): 8-23, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28039129

RESUMO

PREMISE OF THE STUDY: Fibonacci phyllotactic patterns in seed plants are well documented, but whether such predominance holds true for lower vascular plants is relatively unknown. We investigated Diphasiastrum digitatum (Lycopodiaceae) phyllotaxis throughout its ontogeny to extend our knowledge of pattern frequency of lower vascular plants and to measure quantitative variables associated with discontinuous phyllotactic transitions. These investigations allowed us to test whether the same mechanisms inherent in shoot apical meristem (SAM) development of seed plants are applicable to early-diverged lower vascular plants SAM development. METHODS: Divergence angle, plastochron ratio, leaf insertion angle, circumferential ratio, radial ratio, half conic angle, area, circumference, and circularity of the shoot apical meristem were compared among different phyllotactic patterns and different meristem types observed throughout D. digitatum ontogeny, using scanning electron microscopy. KEY RESULTS: Fibonacci patterns were not predominant during six stages of D. digitatum ontogeny. In all five cases of discontinuous transition associated with strobili formation, divergence angle was the only variable that has changed consistently. CONCLUSIONS: The predominance of non-Fibonacci patterns/series in D. digitatum is inconsistent with the prediction of interpretive model of phyllotaxis. We hypothesize this is because its SAM, due to its frequent dichotomy, is not circular and primordia initiation is restricted spatially and temporally at the beginning of pattern formation. Change in divergence angle associated with discontinuous transitions is most likely due to the change of the location of new auxin maxima, due to the change of SAM shape and size.


Assuntos
Lycopodiaceae/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Folhas de Planta/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento , Caules de Planta/crescimento & desenvolvimento , Algoritmos , Lycopodiaceae/ultraestrutura , Meristema/ultraestrutura , Microscopia Eletrônica de Varredura , Modelos Biológicos , Folhas de Planta/ultraestrutura , Brotos de Planta/ultraestrutura , Caules de Planta/ultraestrutura
15.
Protoplasma ; 254(4): 1661-1674, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27957603

RESUMO

This study investigates the histology and subcellular features of secretory cavities during the development of the shoot apex of Metrodorea nigra A. St.-Hil. in order to better understand the functioning of these glands. This Rutaceae species is a very suitable model for studying secretory cavity life span, since the shoot apex exhibits both dormant and growth stages during its annual cycle. Shoot apices were collected during the dormant and growth stages from populations of M. nigra growing under natural conditions. Materials were processed using standard techniques for light and electron microscopy. The secretory cavities originate under the protodermis, and their initiation is restricted to the early developmental stage of shoot organs, which are protected by a hood-shaped structure. Secretory cavities have a multi-seriate epithelium surrounding a lumen that expands schizolysigenously. Oil production begins before lumen formation. When the shoot apex resumes development after the dormant stage, the glands remain active in oil secretion in the developing shoot apex and fully expanded leaves. The mature epithelial cells are flattened and exhibit very thin walls, large oil bodies, leucoplasts surrounded by endoplasmic reticulum, and mitochondria with unusual morphology. The tangential walls of the epithelial cells facing the lumen undergo continuous peeling. The vacuole extrusion appears to be the primary mode of release oil into the lumen, in an exocytotic way. The continuity of oil secretion is ensured by the replacement of the damaged inner epithelial cells by divisions in the parenchyma layer that surround the oil gland, likely a meristematic sheath.


Assuntos
Óleos Vegetais/metabolismo , Brotos de Planta/ultraestrutura , Rutaceae/ultraestrutura , Diferenciação Celular , Óleos Voláteis/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Rutaceae/crescimento & desenvolvimento , Rutaceae/metabolismo , Vacúolos/metabolismo , Vacúolos/ultraestrutura
16.
New Phytol ; 214(1): 81-96, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27859288

RESUMO

The primary thickening growth of Moso (Phyllostachys edulis) underground shoots largely determines the culm circumference. However, its developmental mechanisms remain largely unknown. Using an integrated anatomy, mathematics and genomics approach, we systematically studied cellular and molecular mechanisms underlying the growth of Moso underground shoots. We discovered that the growth displayed a spiral pattern and pith played an important role in promoting the primary thickening process of Moso underground shoots and driving the evolution of culms with different sizes among different bamboo species. Different with model plants, the shoot apical meristem (SAM) of Moso is composed of six layers of cells. Comparative transcriptome analysis identified a large number of genes related to the vascular tissue formation that were significantly upregulated in a thick wall variant with narrow pith cavity, mildly spiral growth, and flat and enlarged SAM, including those related to plant hormones and those involved in cell wall development. These results provide a systematic perspective on the primary thickening growth of Moso underground shoots, and support a plausible mechanism resulting in the narrow pith cavity, weak spiral growth but increased vascular bundle of the thick wall Moso.


Assuntos
Genes de Plantas , Estudos de Associação Genética , Brotos de Planta/citologia , Brotos de Planta/crescimento & desenvolvimento , Poaceae/crescimento & desenvolvimento , Poaceae/genética , Evolução Biológica , Diferenciação Celular/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Parede Celular/genética , Parede Celular/ultraestrutura , Celulose/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Meristema/citologia , Meristema/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Brotos de Planta/genética , Brotos de Planta/ultraestrutura , Feixe Vascular de Plantas/citologia , Feixe Vascular de Plantas/efeitos dos fármacos , Poaceae/citologia , Poaceae/ultraestrutura , Transcriptoma/efeitos dos fármacos , Transcriptoma/genética
17.
Plant Physiol ; 172(1): 416-26, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27474116

RESUMO

The ability of plants to match their reproductive output with favorable environmental conditions has major consequences both for lifetime fitness and geographic patterns of diversity. In temperate ecosystems, some plant species have evolved the ability to use winter nonfreezing cold (vernalization) as a cue to ready them for spring flowering. However, it is unknown how important the evolution of vernalization responsiveness has been for the colonization and subsequent diversification of taxa within the northern and southern temperate zones. Grasses of subfamily Pooideae, including several important crops, such as wheat (Triticum aestivum), barley (Hordeum vulgare), and oats (Avena sativa), predominate in the northern temperate zone, and it is hypothesized that their radiation was facilitated by the early evolution of vernalization responsiveness. Predictions of this early origin hypothesis are that a response to vernalization is widespread within the subfamily and that the genetic basis of this trait is conserved. To test these predictions, we determined and reconstructed vernalization responsiveness across Pooideae and compared expression of wheat vernalization gene orthologs VERNALIZATION1 (VRN1) and VRN3 in phylogenetically representative taxa under cold and control conditions. Our results demonstrate that vernalization responsive Pooideae species are widespread, suggesting that this trait evolved early in the lineage and that at least part of the vernalization gene network is conserved throughout the subfamily. These results are consistent with the hypothesis that the evolution of vernalization responsiveness was important for the initial transition of Pooideae out of the tropics and into the temperate zone.


Assuntos
Temperatura Baixa , Flores/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Poaceae/genética , Avena/genética , Avena/crescimento & desenvolvimento , Teorema de Bayes , Evolução Molecular , Flores/crescimento & desenvolvimento , Hordeum/genética , Hordeum/crescimento & desenvolvimento , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/ultraestrutura , Microscopia Eletrônica de Varredura , Filogenia , Proteínas de Plantas/classificação , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/ultraestrutura , Poaceae/classificação , Poaceae/crescimento & desenvolvimento , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Triticum/genética , Triticum/crescimento & desenvolvimento
18.
Plant Biol (Stuttg) ; 18(5): 851-8, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27208391

RESUMO

Colleters are secretory structure present on many families including Rubiaceae. Particular characteristics have been described about colleters secretory cells, however senescence process are still under debate. Tocoyena bullata (Vell.) Mart. (Rubiaceae) shoot apex were collected at Jardim Botânico do Rio de Janeiro, RJ/Brazil. Stipules were separated and fragments were fixed in 2.5% glutaraldehyde and 4.0% formaldehyde in 0.05 m sodium cacodylate buffer, pH 7.2, post fixed in 1.0% osmium tetroxide in the same buffer, dehydrated in acetone, critical-point-drying, sputtered coated and observed. For light microscopy fragments were fixed and dehydrated, infiltrated with historesin and stained with 1% toluidine blue. For transmission electron microscopy, the samples were infiltrated with Epoxi resin. Colleters are present on stipule adaxial surface. On the beginning of development, these structures are recognized as small projections. Later on, colleters differentiated and secrete by cuticle rupture. The colleters senescence occurs in a concomitant and indissoluble way of programmed cell death. Ultrastructural analyses during the process strongly suggest the senescence is based on a non-autolitic programmed cell death. T. bullata colleters, present at stipule abaxial surface are cylindrical secretory structures. Colleters secretory cells originated as stipule projections; differentiate; secrete and senesce by programmed cell death. The secretion and the cell dead occurs in a concomitantly and indissoluble way.


Assuntos
Rubiaceae/fisiologia , Apoptose , Brasil , Dessecação , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/fisiologia , Brotos de Planta/ultraestrutura , Rubiaceae/crescimento & desenvolvimento , Rubiaceae/ultraestrutura , Especificidade da Espécie
19.
Dev Biol ; 419(1): 114-120, 2016 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-26992363

RESUMO

Recent advances in confocal microscopy, coupled with the development of numerous fluorescent reporters, provide us with a powerful tool to study the development of plants. Live confocal imaging has been used extensively to further our understanding of the mechanisms underlying the formation of roots, shoots and leaves. However, it has not been widely applied to flowers, partly because of specific challenges associated with the imaging of flower buds. Here, we describe how to prepare and grow shoot apices of Arabidopsis in vitro, to perform both single-point and time-lapse imaging of live, developing flower buds with either an upright or an inverted confocal microscope.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Botânica/métodos , Flores/crescimento & desenvolvimento , Microscopia Confocal/métodos , Imagem com Lapso de Tempo/métodos , Arabidopsis/genética , Arabidopsis/ultraestrutura , Botânica/instrumentação , Desenho de Equipamento , Flores/ultraestrutura , Genes Reporter , Inflorescência/crescimento & desenvolvimento , Proteínas Luminescentes/análise , Proteínas Luminescentes/genética , Meristema/crescimento & desenvolvimento , Microscopia Confocal/instrumentação , Fotomicrografia/métodos , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/ultraestrutura , Plantas Geneticamente Modificadas , Imagem com Lapso de Tempo/instrumentação
20.
Biomed Res Int ; 2016: 2820454, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26885503

RESUMO

An efficient protocol for micropropagation of Canna indica L., an economically and pharmaceutically important plant, was standardized using rhizome explants, excised from two-month-old aseptic seedlings. Complete plant regeneration was induced on MS medium supplemented with 3.0 mg/L BAP plus 1.5 mg/L NAA, which produced the highest number of shoots (73.3 ± 0.5%) and roots (86.7 ± 0.4%) after 2 weeks. Furthermore, the optimum media for multiple shoots regeneration were recorded on MS enriched with 7.0 mg/L BAP (33.0 ± 0.5%). Plantlets obtained were transplanted to pots after two months and acclimatized in the greenhouse, with 75% survival. In addition, ultrastructural studies showed that rhizomes of in vitro grown specimens were underdeveloped compared to the in vivo specimens, possibly due to the presence of wide spaces. Meanwhile, the leaves of in vivo specimens had more open stomata compared to in vitro specimens, yet their paracytic stomata structures were similar. Hence, there were no abnormalities or major differences between in vitro regenerants and mother plants.


Assuntos
Técnicas de Cultura de Células/métodos , Organogênese , Plantas Medicinais/crescimento & desenvolvimento , Zingiberales/crescimento & desenvolvimento , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/ultraestrutura , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/ultraestrutura , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/ultraestrutura , Plantas Medicinais/ultraestrutura , Plântula/crescimento & desenvolvimento , Plântula/ultraestrutura , Zingiberales/ultraestrutura
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